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  • 1.
    Ahmed, Faisal
    et al.
    Department of Computer Science and Engineering, Premier University, Chattogram 4000, Bangladesh.
    Hossain, Mohammad Shahadat
    Department of Computer Science and Engineering, University of Chittagong, Chittagong 4331, Bangladesh.
    Islam, Raihan Ul
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Andersson, Karl
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    An Evolutionary Belief Rule-Based Clinical Decision Support System to Predict COVID-19 Severity under Uncertainty2021Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 11, nr 13, artikkel-id 5810Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Accurate and rapid identification of the severe and non-severe COVID-19 patients is necessary for reducing the risk of overloading the hospitals, effective hospital resource utilization, and minimizing the mortality rate in the pandemic. A conjunctive belief rule-based clinical decision support system is proposed in this paper to identify critical and non-critical COVID-19 patients in hospitals using only three blood test markers. The experts’ knowledge of COVID-19 is encoded in the form of belief rules in the proposed method. To fine-tune the initial belief rules provided by COVID-19 experts using the real patient’s data, a modified differential evolution algorithm that can solve the constraint optimization problem of the belief rule base is also proposed in this paper. Several experiments are performed using 485 COVID-19 patients’ data to evaluate the effectiveness of the proposed system. Experimental result shows that, after optimization, the conjunctive belief rule-based system achieved the accuracy, sensitivity, and specificity of 0.954, 0.923, and 0.959, respectively, while for disjunctive belief rule base, they are 0.927, 0.769, and 0.948. Moreover, with a 98.85% AUC value, our proposed method shows superior performance than the four traditional machine learning algorithms: LR, SVM, DT, and ANN. All these results validate the effectiveness of our proposed method. The proposed system will help the hospital authorities to identify severe and non-severe COVID-19 patients and adopt optimal treatment plans in pandemic situations.

    Fulltekst (pdf)
    fulltext
  • 2.
    Al-Jabban, Wathiq
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Laue, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Al-Ansari, Nadhir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    A Comparative Evaluation of Cement and By-Product Petrit T in Soil Stabilization2019Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 9, nr 23, artikkel-id 5238Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study presents a comparison between the effectiveness of adding low binder amounts of industrial by-product Petrit T as well as cement to modify and improve fine-grained soil. Binder amount was added by soil dry weight; cement at 1%, 2%, 4% and 7% and Petrit T at 2%, 4% and 7%. The unconfined compressive strength (UCS) was used as an indicator of soil strength. In addition, the consistency limits, laser particle size analysis, and pH tests were also conducted on the treated soil. The samples were cured at 20 °C for different periods from 7 to 90 days before testing. Results indicate that cement is more effective at improving the physical and engineering properties of the treated soil. Soil plasticity index decreases after treatment and with time. Liquidity index and the water content to plastic limit ratio are introduced as new indices to define the improvement in the workability of treated soil. Soil particle size distribution is changed by reducing the clay size fraction and increasing the silt size fraction after treatment. The findings confirm that adding small binder contents improve soil properties, which subsequently reduce the environmental threats and costs that are associated with using a high amount of binder.

    Fulltekst (pdf)
    fulltext
  • 3.
    Al-Jabban, Wathiq
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi. Engineering Dept., University of Babylon, Babylon, Iraq.
    Laue, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Al-Ansari, Nadhir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Effect of Disintegration Times of the Homogeneity of Soil prior to Treatment2019Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 9, nr 22, artikkel-id 4791Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents an experimental study to investigate the effect of various disintegration times on the homogeneity of pre-treated natural soil before mixing with cementitious binders. Various disintegration times were applied, ranging from 10 s to 120 s. Four different soils were used with different characteristics from high, medium and low plasticity properties. Visual and sieving assessment were used to evaluate the best disintegration times to allow for a uniform distribution of water content and small-sized particles that would produce a uniform distribution of the binder around the soil particles. Results showed that a proper mixing time to homogenize and disintegrate the soil prior to treatment depended on several factors: soil type, water content and plasticity properties. For high plasticity soil, the disintegration time should be kept as short as possible. Increasing the disintegration time ha negative effects on the uniformity of distribution of the binder around soil particles. The homogenizing and disintegration time were less important for low plasticity soils with low water content than for medium to high plasticity soils. The findings could assist various construction projects that deal with soil improvement through preparation of soil before adding a cementitious binder to ensure uniformity of distribution of the binder around soil particles and obtain uniform soil–binder mixtures

    Fulltekst (pdf)
    fulltext
  • 4.
    Al-Janabi, Ahmed Mohammed Sami
    et al.
    Department of Civil Engineering, Faculty of Engineering, Universiti Putra Malaysia, UPM Serdang, Selangor 43400, Malaysia.
    Ghazali, Abdul Halim
    Department of Civil Engineering, Faculty of Engineering, Universiti Putra Malaysia, UPM Serdang, Selangor 43400, Malaysia.
    Yusuf, Badronnisa
    Department of Civil Engineering, Faculty of Engineering, Universiti Putra Malaysia, UPM Serdang, Selangor 43400, Malaysia.
    Sammen, Saad Sh.
    Department of Civil Engineering, College of Engineering, University of Diyala, Diyala Governorate, Iraq.
    Afan, Haitham Abdulmohsin
    Institute of Research and Development, Duy Tan University, Da Nang 550000, Vietnam.
    Al-Ansari, Nadhir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Shahid, Shamsuddin
    School of Civil Engineering, Faculty of Engineering, Universiti Teknologi Malaysia (UTM), Johor Bahru 81310, Malaysia.
    Yaseen, Zaher Mundher
    Sustainable Developments in Civil Engineering Research Group, Faculty of Civil Engineering, Ton Duc Thang University, Ho Chi Minh City, Vietnam.
    Optimizing Height and Spacing of Check Dam Systems for Better Grassed Channel Infiltration Capacity2020Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 10, nr 11, artikkel-id 3725Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The check dams in grassed stormwater channels enhance infiltration capacity by temporarily blocking water flow. However, the design properties of check dams, such as their height and spacing, have a significant influence on the flow regime in grassed stormwater channels and thus channel infiltration capacity. In this study, a mass-balance method was applied to a grassed channel model to investigate the effects of height and spacing of check dams on channel infiltration capacity. Moreover, an empirical infiltration model was derived by improving the modified Kostiakov model for reliable estimation of infiltration capacity of a grassed stormwater channel due to check dams from four hydraulic parameters of channels, namely, the water level, channel base width, channel side slope, and flow velocity. The result revealed that channel infiltration was increased from 12% to 20% with the increase of check dam height from 10 to 20 cm. However, the infiltration was found to decrease from 20% to 19% when a 20 cm height check dam spacing was increased from 10 to 30 m. These results indicate the effectiveness of increasing height of check dams for maximizing the infiltration capacity of grassed stormwater channels and reduction of runoff volume.

    Fulltekst (pdf)
    fulltext
  • 5.
    Alonso-Rosa, Manuel
    et al.
    University of Cordoba.
    Gil-de-Castro, Aurora
    University of Cordoba.
    Moreno-Munoz, Antonio
    University of Cordoba.
    Garrido-Zafra, Joaquin
    University of Cordoba.
    Gutierrez-Ballesteros, Elena
    University of Cordoba.
    Cañete-Carmona, Eduardo
    University of Cordoba.
    An IoT based mobile augmented reality application for energy visualization in buildings environments2020Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 10, nr 2, artikkel-id 600Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Augmented reality (AR) improves how we acquire, understand, and display information without distracting us from the real world. These technologies can be used in different applications and industries as they can incorporate domain-specific visualizations on a real-world screen. Mobile augmented reality (MAR) essentially consists of superimposing virtual elements over real objects on the screen, to give added value and enrich the interaction with reality. In numerous plants, it is being used for maintenance and repair tasks, as well as training. The Internet of Things (IoT) is increasingly pervading every aspect of our lives, including the power infrastructure of our buildings. IoT-enabled devices offer many connectivity options for helping supervise all-important energy assets. Aggregating data to cloud-based platforms enables operations teams to have on-time information access to make fast decisions and have a fast response regarding energy use, while maintenance teams keep on top of the appliance power quality and reliability needed by using MAR. This paper presents a novel approximation for visualizing appliance-related power quality to enhance awareness about the consumed electricity. A combined solution of MAR with IoT technologies is employed. Engineered solutions’ hands-free way to get data about surrounding appliances reduces the complexity, saves energy, and speeds up the operations. An innovative way to measure things at the right time leads to a competitive advantage.

    Fulltekst (pdf)
    fulltext
  • 6.
    Amini, Ata
    et al.
    Kurdistan Agricultural and Natural Resources Research and Education Center, AREEO, Sanandaj, Iran.
    Kolahchi, Abdolnabi Abdeh
    Soil Conservation and Watershed Management Research Institute, SCWMRI, AREEO, Tehran, Iran.
    Al-Ansari, Nadhir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Moghadam, Mehdi Karami
    Department of Agriculture, Payame Noor University (PNU), Tehran, Iran.
    Mohammad, Thamer
    Department of Water Resources Engineering, College of Engineering, University of Baghdad, Baghdad, Iraq.
    Application of TRMM Precipitation Data to Evaluate Drought and Its Effects on Water Resources Instability2019Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 9, nr 24, artikkel-id 5377Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The present research was carried out to study drought and its effects upon water resources using remote sensing data. To this end, the tropical rainfall measuring mission (TRMM) satellite precipitation, the synoptic stations, and fountain discharge data were employed. For monitoring of drought in the study area, in Kermanshah province, Iran, the monthly precipitation data of the synoptic stations along with TRMM satellite precipitation datasets were collected and processed in the geographic information system (GIS) environment. Statistical indicators were applied to evaluate the accuracy of TRMM precipitation against the meteorological stations’ data. Standardized precipitation index, SPI, and normalized fountain discharge were used in the monitoring of drought conditions, and fountains discharge, respectively. The fountains were selected so that in addition to enjoying the most discharge rates, they spread along the study area. The evaluation of precipitation data showed that the TRMM precipitation data were of high accuracy. Studies in temporal scale are indicative of the strike of drought in this region to the effect that for most months of the year, frequency and duration in dry periods are much more than in wet periods. As for seasonal scales, apart from winter, the frequency and duration of drought in spring and autumn have been longer than in wet years. Moreover, the duration of these periods was different. A comparison between the results of changes in fountain discharges and drought index in the region has verified that the drought has caused a remarkable decline in the fountain discharges.

    Fulltekst (pdf)
    fulltext
  • 7.
    Andersson, Anton
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Brander, Linus
    Division of Built Environment—Infrastructure and Concrete, Research Institute of Sweden, SE-501 15 Borås, Sweden.
    Lennartsson, Andreas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Roos, Ake
    Boliden AB, SE-101 20 Stockholm, Sweden.
    Engström, Fredrik
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    A Method for Synthesizing Iron Silicate Slags to Evaluate Their Performance as Supplementary Cementitious Materials2023Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 13, nr 14, artikkel-id 8357Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Utilizing iron silicate copper slag as supplementary cementitious material (SCM) is a means to improve resource efficiency and lower the carbon dioxide emissions from cement production. Despite multiple studies on the performance of these slags in SCM applications, the variations in cooling procedure, grinding, and methods for evaluating reactivity limit the ability to assess the influence of chemical composition on reactivity from the literature data. In this study, a methodology was developed to synthesize iron silicate slags, which were then evaluated for their inherent reactivity using the R-3 calorimeter-based experiments. The results demonstrated that laboratory-scale granulation produced the same reactivity as industrially granulated slag. Furthermore, a synthesized triplicate sample showed high repeatability. Based on these two aspects, this method can be used to systematically study the influence of chemical composition on the inherent reactivity of iron silicate slags while producing results that are directly translatable to industrial slags.

    Fulltekst (pdf)
    fulltext
  • 8.
    Awad, Ali Ismail
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap. Faculty of Engineering, Al-Azhar University, Qena, Egypt. Centre for Security, Communications and Network Research, University of Plymouth, Plymouth, UK.
    Hassaballah, M.
    Department of Computer Science, Faculty of Computers and Information, South Valley University, Qena, Egypt.
    Bag-of-Visual-Words for Cattle Identification from Muzzle Print Images2019Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 9, nr 22, artikkel-id 4914Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cattle, buffalo and cow identification plays an influential role in cattle traceability from birth to slaughter, understanding disease trajectories and large-scale cattle ownership management. Muzzle print images are considered discriminating cattle biometric identifiers for biometric-based cattle identification and traceability. This paper presents an exploration of the performance of the bag-of-visual-words (BoVW) approach in cattle identification using local invariant features extracted from a database of muzzle print images. Two local invariant feature detectors—namely, speeded-up robust features (SURF) and maximally stable extremal regions (MSER)—are used as feature extraction engines in the BoVW model. The performance evaluation criteria include several factors, namely, the identification accuracy, processing time and the number of features. The experimental work measures the performance of the BoVW model under a variable number of input muzzle print images in the training, validation, and testing phases. The identification accuracy values when utilizing the SURF feature detector and descriptor were 75%, 83%, 91%, and 93% for when 30%, 45%, 60%, and 75% of the database was used in the training phase, respectively. However, using MSER as a points-of-interest detector combined with the SURF descriptor achieved accuracies of 52%, 60%, 67%, and 67%, respectively, when applying the same training sizes. The research findings have proven the feasibility of deploying the BoVW paradigm in cattle identification using local invariant features extracted from muzzle print images. 

  • 9.
    Belay, Birhanu
    et al.
    Department of Computer Science, University of Kaiserslautern, Germany; Faculty of Computing, Bahir Dar Institute of Technology, Ethiopia.
    Habtegebrial, Tewodros
    Department of Computer Science, University of Kaiserslautern, Germany.
    Meshesha, Million
    School of Information Science, Addis Ababa University, Ethiopia.
    Liwicki, Marcus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Belay, Gebeyehu
    Faculty of Computing, Bahir Dar Institute of Technology, Ethiopia.
    Stricker, Didier
    Department of Computer Science, University of Kaiserslautern, Germany; German Research Center for Artificial Intelligence, DFKI, Germany.
    Amharic OCR: An End-to-End Learning2020Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 10, nr 3, artikkel-id 1117Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this paper, we introduce an end-to-end Amharic text-line image recognition approach based on recurrent neural networks. Amharic is an indigenous Ethiopic script which follows a unique syllabic writing system adopted from an ancient Geez script. This script uses 34 consonant characters with the seven vowel variants of each (called basic characters) and other labialized characters derived by adding diacritical marks and/or removing parts of the basic characters. These associated diacritics on basic characters are relatively smaller in size, visually similar, and challenging to distinguish from the derived characters. Motivated by the recent success of end-to-end learning in pattern recognition, we propose a model which integrates a feature extractor, sequence learner, and transcriber in a unified module and then trained in an end-to-end fashion. The experimental results, on a printed and synthetic benchmark Amharic Optical Character Recognition (OCR) database called ADOCR, demonstrated that the proposed model outperforms state-of-the-art methods by 6.98% and 1.05%, respectively.

  • 10.
    Benti, Gudeta Berhanu
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Produkt- och produktionsutveckling.
    Aidanpää, Jan-Olov
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Produkt- och produktionsutveckling.
    Gustavsson, Rolf
    Vattenfall AB Research and Development, 814 26 Älvkarleby, Sweden.
    Cost-Effective Design Modification of a Sleeve Bearing with Large Bearing Clearance2024Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 14, nr 3, artikkel-id 1214Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In 2015, a 45 MW vertical hydropower machine exhibited excessive vibration after refurbishment. Measurements revealed a substantial bearing clearance at the lower generator guide bearing. Consequently, the bearing was unable to generate sufficient opposing force to drive the rotor toward the bearing center, resulting in more pronounced overall system vibration. Addressing this challenge required a cost-effective and feasible solution for mitigating the vibration problem. To this end, a design modification was implemented wherein the lower generator guide bearing (originally a sleeve bearing) was modified to a four-lobe bearing by offsetting the two halves of the bearing twice in two axes. Numerical simulations and experimentations were conducted, and the dynamics of the machine before and after the design modification were investigated. Both the simulation and experimental results showed that the machine with the four-lobe bearing improved the system stability and reduced the vibration amplitudes. The numerical simulation result demonstrated that, due to the design modification, the first and second critical speeds were effectively eliminated for a speed range of up to three times the nominal speed. Furthermore, for nominal operation with unbalanced magnetic pull, the four-lobe bearing provided a stability advantage in terms of the modal parameters relative to the original sleeve bearing.

    Fulltekst (pdf)
    fulltext
  • 11.
    Björling, Marcus
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Bair, Scott
    Georgia Institute of Technology, Centre for High Pressure Rheology, G.W. Woodruff School of Mechanical Engineering, Atlanta, GA.
    Mu, Liwen
    Intelligent Composites Laboratory, Department of Chemical and Biomolecular Engineering, The University of Akron.
    Zhu, Jiahua
    Intelligent Composites Laboratory, Department of Chemical and Biomolecular Engineering, The University of Akron.
    Shi, Yijun
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Elastohydrodynamic performance of a bio-based, non-corrosive ionic liquid2017Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 17, nr 10, artikkel-id 996Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    To improve performance of machine components, lubrication is one of the most important factors. Especially for use in extreme environments, researchers look for other solutions rather than common lubricant base stocks like mineral oils or vegetable oils. One such example is ionic liquids. Ionic liquids have been defined as molten salts with melting points below 100 °C that are entirely ionic in nature, comprising both cationic and anionic species. The industrial use of ionic liquids is mostly as solvents, electrolytes, extractants and catalysts. In tribological applications, ionic liquids are mainly studied in boundary lubrication and in pure sliding contacts. In this work, the elastohydrodynamic performance of a bio-based, non-corrosive, [choline][L-proline] ionic liquid is evaluated in terms of pressure-viscosity response, film forming capability and friction. The results show a pressure-viscosity coefficient of below 8 GPa-1 at 25 °C, among the lowest reported for any ionic liquid. The ionic liquid generated up to 70% lower friction than a reference paraffin oil with a calculated difference in film thickness of 11%. It was also shown that this ionic liquid is very hygroscopic, which is believed to explain part of the low friction results, but also has to be considered in practical applications since the water content will influence the properties and thus the performance of the lubricant.

  • 12.
    Borngrund, Carl
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Bodin, Ulf
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Andreasson, Henrik
    School of Science and Technology, Örebro University, Fakultetsgatan 1, Örebro, 70182, Sweden.
    Sandin, Fredrik
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Automating the Short-Loading Cycle: Survey and Integration Framework2024Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 14, nr 11, artikkel-id 4674Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The short-loading cycle is a construction task where a wheel loader scoops material from a nearby pile in order to move that material to the tipping body of a dump truck. The short-loading cycle is a vital task performed in high quantities and is often part of a more extensive never-ending process to move material for further refinement. This, together with the highly repetitive nature of the short-loading cycle, makes it a suitable candidate for automation. However, the short-loading cycle is a complex task where the mechanics of the wheel loader together with the interaction between the wheel loader and the environment needs to be considered. This must be achieved while maintaining some productivity goal and, concurrently, minimizing the used energy. The main objective of this work is to analyze the short-loading cycle, assess the current state of research in this field, and discuss the steps required to progress towards a minimal viable product consisting of individual automation solutions that can perform the short-loading cycle well enough to be used by early adopters. This is achieved through a comprehensive literature study and consequent analysis of the review results. From this analysis, the requirements of an MVP are defined and some gaps which are currently hindering the realization of the MVP are presented.

    Fulltekst (pdf)
    fulltext
  • 13.
    Chandran, Praneeth
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Thiery, Florian
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Odelius, Johan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Famurewa, Stephen Mayowa
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Lind, Håkan
    Bombardier Transport, 11743 Stockholm, Sweden.
    Rantatalo, Matti
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Supervised Machine Learning Approach for Detecting Missing Clamps in Rail Fastening System from Differential Eddy Current Measurements2021Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 11, nr 9, artikkel-id 4018Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The rail fastening system forms an integral part of rail tracks, as it maintains the rail in a fixed position, upholding the track stability and track gauge. Hence, it becomes necessary to monitor their conditions periodically to ensure safe and reliable operation of the railway. Inspection is normally carried out manually by trained operators or by employing 2-D visual inspection methods. However, these methods have drawbacks when visibility is minimal and are found to be expensive and time consuming. In the previous study, the authors proposed a train-based differential eddy current sensor system that uses the principle of electromagnetic induction for inspecting the railway fastening system that can overcome the above-mentioned challenges. The sensor system includes two individual differential eddy current sensors with a driving field frequency of 18 kHz and 27 kHz respectively. This study analyses the performance of a machine learning algorithm for detecting and analysing missing clamps within the fastening system, measured using a train-based differential eddy current sensor. The data required for the study was collected from field measurements carried out along a heavy haul railway line in the north of Sweden, using the train-based differential eddy current sensor system. Six classification algorithms are tested in this study and the best performing model achieved a precision and recall of 96.64% and 95.52% respectively. The results from the study shows that the performance of the machine learning algorithms improved when features from both the driving channels were used simultaneously to represent the fasteners. The best performing algorithm also maintained a good balance between the precision and recall scores during the test stage.

    Fulltekst (pdf)
    fulltext
  • 14.
    Dunst, Anna Katharina
    et al.
    Fachbereich Ausdauer, Institut für Angewandte Trainingswissenschaft, 04109 Leipzig, Germany.
    Grüneberger, René
    Monteverde Bicycles, 10625 Berlin, Germany.
    Holmberg, Hans-Christer
    Luleå tekniska universitet, Institutionen för hälsa, lärande och teknik, Hälsa, medicin och rehabilitering.
    Modeling optimal cadence as a function of time during maximal sprint exercises can improve performance by elite track cyclists2021Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 11, nr 24, artikkel-id 12105Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In track cycling sprint events, optimal cadence PRopt is a dynamic aspect of fatigue. It is currently unclear what cadence is optimal for an athlete’s performance in sprint races and how it can be calculated. We examined fatigue-induced changes in optimal cadence during a maximal sprint using a mathematical approach. Nine elite track cyclists completed a 6-s high-frequency pedaling test and a 60-s isokinetic all-out sprint on a bicycle ergometer with continuous monitoring of crank force and cadence. Fatigue-free force-velocity (F/v) and power-velocity (P/v) profiles were derived from both tests. The development of fatigue during the 60-s sprint was assessed by fixing the slope of the fatigue-free F/v profile. Fatigue-induced alterations in PRopt were determined by non-linear regression analysis using a mono-exponential equation at constant slope. The study revealed that PRopt at any instant during a 60-s maximal sprint can be estimated accurately using a mono-exponential equation. In an isokinetic mode, a mean PRopt can be identified that enables the athlete to generate the highest mean power output over the course of the effort. Adding the time domain to the fatigue-free F/v and P/v profiles allows time-dependent cycling power to be modelled independent of cadence. 

  • 15.
    Enrichi, Francesco
    et al.
    CNR-ISP Istituto di Scienze Polari, c/o campus scientifico Università Ca’ Foscari Venezia, via Torino 155, 30172 Mestre-Venezia, Italy. Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca’ Foscari Venezia, via Torino 155, 30172 Mestre-Venezia, Italy.
    Cattaruzza, Elti
    Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca’ Foscari Venezia, via Torino 155, 30172 Mestre-Venezia, Italy.
    Finotto, Tiziano
    Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca’ Foscari Venezia, via Torino 155, 30172 Mestre-Venezia, Italy.
    Riello, Pietro
    Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca’ Foscari Venezia, via Torino 155, 30172 Mestre-Venezia, Italy.
    Righini, Giancarlo C.
    Museo Storico della Fisica e Centro Studi e Ricerche “Enrico Fermi”, Piazza del Viminale 1, 00184 Roma, Italy. CNR-IFAC Istituto di Fisica Applicata Nello Carrara, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Firenze, Italy.
    Trave, Enrico
    Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca’ Foscari Venezia, via Torino 155, 30172 Mestre-Venezia, Italy.
    Vomiero, Alberto
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap. Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca’ Foscari Venezia, via Torino 155, 30172 Mestre-Venezia, Italy.
    Ag-Sensitized NIR-Emitting Yb3+-Doped Glass-Ceramics2020Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 10, nr 6, artikkel-id 2184Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The optical photoluminescent (PL) emission of Yb3+ ions in the near infrared (NIR) spectral region at about 950–1100 nm has many potential applications, from photovoltaics to lasers and visual devices. However, due to their simple energy-level structure, Yb3+ ions cannot directly absorb UV or visible light, putting serious limits on their use as light emitters. In this paper we describe a broadband and efficient strategy for sensitizing Yb3+ ions by Ag codoping, resulting in a strong 980 nm PL emission under UV and violet-blue light excitation. Yb-doped silica–zirconia–soda glass–ceramic films were synthesized by sol-gel and dip-coating, followed by annealing at 1000 °C. Ag was then introduced by ion-exchange in a molten salt bath for 1 h at 350 °C. Different post-exchange annealing temperatures for 1 h in air at 380 °C and 430 °C were compared to investigate the possibility of migration/aggregation of the metal ions. Studies of composition showed about 1–2 wt% Ag in the exchanged samples, not modified by annealing. Structural analysis reported the stabilization of cubic zirconia by Yb-doping. Optical measurements showed that, in particular for the highest annealing temperature of 430 °C, the potential improvement of the material’s quality, which would increase the PL emission, is less relevant than Ag-aggregation, which decreases the sensitizers number, resulting in a net reduction of the PL intensity. However, all the Ag-exchanged samples showed a broadband Yb3+ sensitization by energy transfer from Ag aggregates, clearly attested by a broad photoluminescence excitation spectra after Ag-exchange, paving the way for applications in various fields, such as solar cells and NIR-emitting devices.

  • 16.
    Fanizza, Elisabetta
    et al.
    Dipartimento di Chimica, Università degli Studi di Bari, Via Orabona 4, 70126 Bari, Italy. CNR-IPCF, SSO Bari, Via Orabona 4, 70126 Bari, Italy.
    Zhao, Haiguang
    State Key Laboratory of Bio-Fibers and Eco-Textiles, College of Physics, Qingdao University, No. 308 Ningxia Road, Qingdao 266071, China.
    De Zio, Simona
    Dipartimento di Chimica, Università degli Studi di Bari, Via Orabona 4, 70126 Bari, Italy. Dipartimento di Chimica “Giacomo Ciamician”, Università degli Studi di Bologna, Via Selmi 2, Bologna, Italy.
    Depalo, Nicoletta
    CNR-IPCF, SSO Bari, Via Orabona 4, 70126 Bari, Italy.
    Rosei, Federico
    Centre Énergie, Matériaux et Télécommunications, Institut National de la Recherche Scientifique, 1650 Boul. Lionel Boulet, Varennes, QC J3X 1S2, Canada.
    Vomiero, Alberto
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap. Department of Molecular Sciences and Nanosystems, Ca’ Foscari University of Venice, Via Torino 155, 30172 Venezia Mestre, Italy.
    Curri, M. Lucia
    Dipartimento di Chimica, Università degli Studi di Bari, Via Orabona 4, 70126 Bari, Italy. CNR-IPCF, SSO Bari, Via Orabona 4, 70126 Bari, Italy.
    Striccoli, Marinella
    CNR-IPCF, SSO Bari, Via Orabona 4, 70126 Bari, Italy.
    Encapsulation of Dual Emitting Giant Quantum Dots in Silica Nanoparticles for Optical Ratiometric Temperature Nanosensors2020Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 10, nr 8, artikkel-id 2767Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Accurate temperature measurements with a high spatial resolution for application in the biomedical fields demand novel nanosized thermometers with new advanced properties. Here, a water dispersible ratiometric temperature sensor is fabricated by encapsulating in silica nanoparticles, organic capped PbS@CdS@CdS “giant” quantum dots (GQDs), characterized by dual emission in the visible and near infrared spectral range, already assessed as efficient fluorescent nanothermometers. The chemical stability, easy surface functionalization, limited toxicity and transparency of the silica coating represent advantageous features for the realization of a nanoscale heterostructure suitable for temperature sensing. However, the strong dependence of the optical properties on the morphology of the final core–shell nanoparticle requires an accurate control of the encapsulation process. We carried out a systematic investigation of the synthetic conditions to achieve, by the microemulsion method, uniform and single core silica coated GQD (GQD@SiO2) nanoparticles and subsequently recorded temperature-dependent fluorescent spectra in the 281-313 K temperature range, suited for biological systems. The ratiometric response—the ratio between the two integrated PbS and CdS emission bands—is found to monotonically decrease with the temperature, showing a sensitivity comparable to bare GQDs, and thus confirming the effectiveness of the functionalization strategy and the potential of GQD@SiO2 in future biomedical applications.

  • 17.
    Garcia Represa, Jaime
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Larrinaga, Felix
    Information Systems, Faculty of Engineering, Mondragon Unibertsitatea, Gipuzkoa, Arrasate-Mondragon, Arrasate, 20500, Spain.
    Varga, Pal
    Department of Telecommunications and Media Informatics, Faculty of Electrical Engineering and Informatics, Budapest University of Technology and Economics, Műegyetem rkp. 3., Budapest, H-1111, Hungary.
    Ochoa, William
    Information Systems, Faculty of Engineering, Mondragon Unibertsitatea, Gipuzkoa, Arrasate-Mondragon, Arrasate, 20500, Spain.
    Perez, Alain
    Information Systems, Faculty of Engineering, Mondragon Unibertsitatea, Gipuzkoa, Arrasate-Mondragon, Arrasate, 20500, Spain.
    Kozma, Dániel
    Department of Telecommunications and Media Informatics, Faculty of Electrical Engineering and Informatics, Budapest University of Technology and Economics, Műegyetem rkp. 3., Budapest, H-1111, Hungary.
    Delsing, Jerker
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Investigation of Microservice-Based Workflow Management Solutions for Industrial Automation2023Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 13, nr 3, artikkel-id 1835Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In an era ruled by data and information, engineers need new tools to cope with the increased complexity of industrial operations. New architectural models for industry enable open communication environments, where workflows can play a major role in providing flexible and dynamic interactions between systems. Workflows help engineers maintain precise control over their factory equipment and Information Technology (IT) services, from the initial design stages to plant operations. The current application of workflows departs from the classic business workflows that focus on office automation systems in favor of a manufacturing-oriented approach that involves direct interaction with cyber-physical systems (CPSs) on the shop floor. This paper identifies relevant industry-related challenges that hinder the adoption of workflow technology, which are classified within the context of a cohesive workflow lifecycle. The classification compares the various workflow management solutions and systems used to monitor and execute workflows. These solutions have been developed alongside the Eclipse Arrowhead framework, which provides a common infrastructure for designing systems according to the microservice architectural principles. This paper investigates and compares various solutions for workflow management and execution in light of the associated industrial requirements. Further, it compares various microservice-based approaches and their implementation. The objective is to support industrial stakeholders in their decision-making with regard to choosing among workflow management solutions.

    Fulltekst (pdf)
    fulltext
  • 18.
    Garg, Kanika
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Kuhn, Thomas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Balloon design for Mars, Venus, and Titan atmospheres2020Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 10, nr 9, artikkel-id 3204Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper studies the specifications of balloons for the exploration of bodies with different atmospheric conditions. Three types of balloons, i.e., zero-pressure, super-pressure, and over-pressurized, with four different shapes, i.e., sphere, oblate, prolate, and airship, were analysed. First, the development of a simulation tool is described, which was used for analysing the behaviour of balloons for different exploration missions. Next, the developed software was verified by comparing its output with recorded data from a set of flights at the Esrange Space Center. Based on the simulation results, recommendations are given for different balloon types and shapes for operation on Mars, Venus, and Titan.

  • 19.
    Gunnvard, Per
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Mattsson, Hans
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Laue, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Evaluating the Design Criteria for Light Embankment Piling: Timber Piles in Road and Railway Foundations2022Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 12, nr 1, artikkel-id 166Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Three-dimensional finite element (FE) simulations were performed to further develop the Swedish design guidelines for geogrid-reinforced timber pile-supported embankments, also known as lightly piled embankments. Lightly piled embankments are constructed mainly in areas which typically have highly compressible soils, and the method utilises untreated timber piles as its key feature. The timber piles are installed in a triangular arrangement instead of the more common square arrangement, with a centre-to-centre distance of 0.8–1.2 m. The aim of this study was to evaluate the current standard using FE modelling setups with square and triangular pile arrangements with varying centre-to-centre distances, based on a typical road foundation case. The evaluation mainly focused on comparing the embankment settlements, as well as the load and stress distribution in the embankment, the piles and the geosynthetic reinforcement. As part of the evaluation, a state-of-the-art study was done on international design guidelines and analytical models. From the FE simulations, no evident difference in mechanical behaviour was found between the triangular and square piling patterns. The maximum allowed centre-to-centre distance between piles can potentially be increased to 1.4 m, decreasing the number of piles by as much as one third.

    Fulltekst (pdf)
    fulltext
  • 20.
    Hajiyan, Ebrahim
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Couceiro, José
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Hansson, Lars
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik. Department of Ocean Operations and Civil Engineering, Faculty of Engineering, Norwegian University of Science and Technology, 6025 Ålesund, Norway.
    Sandberg, Dick
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Drying Behaviour of Western Hemlock with Schedules Developed for Norway Spruce and Scots Pine2023Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 13, nr 19, artikkel-id 11083Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Determining moisture content (MC) distribution during the drying of porous materials such as wood is crucial for developing drying schedules and assessing their suitability to achieve optimised processes. This study aimed to determine the causes of the unique drying behaviour and the well-known unusual longer drying time of western hemlock compared to other similar softwoods. In situ X-ray computed tomography (CT) was used to study the evolution of MC in timber during the drying process. The drying behaviour of western hemlock (Tsuga heterophylla (Raf.) Sarg.) was compared with Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris L.) from green to oven-dried condition with industry-proposed drying schedules used for steering a custom-made experimental kiln combined with a CT scanner. CT scanning was performed at 30 min intervals during the complete drying period of 30 h, and the CT images were processed to calculate the MC evolution within the specimen. Western hemlock showed a considerably slower capillary-phase drying and did not go into the transition and diffusion phases when a schedule adapted to pine and spruce drying was applied for its drying. CT images and MC gradient calculations showed a lower drying rate and severe non-uniformity in MC distribution, which could be due to the effect of higher green MC and the presence of wet pockets. Furthermore, the evaporation front at the first 5 h of drying receded faster into the hemlock specimen, and as drying proceeded, it slowed down compared to other specimens.

    Fulltekst (pdf)
    fulltext
  • 21.
    Haluska, Jakub
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Koval, Anton
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Nikolakopoulos, George
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    On the Unification of Legged and Aerial Robots for Planetary Exploration Missions2022Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 12, nr 8, artikkel-id 3983Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this article, we address the task of developing a unified solution that incorporates quadruped and aerial robots for planetary exploration missions. The designing process takes recommendations provided by Boston Dynamics for building custom payloads for the Spot robot, as well as its kinematic constraints. The unification task itself encompasses design of a passive drone landing platform as a hardware link between the Spot robot and the drone, which has active locking and unlocking capabilities required to securely keep the drone on the Spot independently whether it is standing or moving. Thus, in the designed unification solution, the landing platform does not impact the overall robot mobility and has no interference with the robot’s legs. The initial solution design was extensively evaluated in a series of tests at the laboratory, which demonstrated its viability.

  • 22.
    Hashim, Bassim Mohammed
    et al.
    Ministry of Science and Technology, AL Mustansiriyah University, Baghdad, Iraq.
    Sultan, Maitham Abdullah
    Ministry of Science and Technology, AL Mustansiriyah University, Baghdad, Iraq.
    Attyia, Mazin Najem
    Iraqi Atomic Energy Commission, Baghdad, Iraq.
    Al Maliki, Ali A.
    Ministry of Science and Technology, AL Mustansiriyah University, Baghdad, Iraq.
    Al-Ansari, Nadhir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Change Detection and Impact of Climate Changes to Iraqi Southern Marshes Using Landsat 2 MSS, Landsat 8 OLI and Sentinel 2 MSI Data and GIS Applications2019Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 9, nr 10, artikkel-id 2016Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Marshes represent a unique ecosystem covering a large area of southern Iraq. In a major environmental disaster, the marshes of Iraq were drained, especially during the 1990s. Since then, droughts and the decrease in water imports from the Tigris and Euphrates rivers from Turkey and Iran have prevented them from regaining their former extent. The aim of this research is to extract the values of the normalized dierence vegetation index (NDVI) for the period 1977–2017 from Landsat 2 MSS (multispectral scanner), Landsat 8 OLI (operational land imager) and Sentinel 2 MSI (multi-spectral imaging mission) satellite images and use supervised classification to quantify land and water cover change. The results from the two satellites (Landsat 2 and Landsat 8) are compared with Sentinel 2 to determine the best tool for detecting changes in land and water cover. We also assess the potential impacts of climate change through the study of the annual average maximum temperature and recipitation in dierent areas in the marshes for the period 1981–2016. The NDVI analysis and image classification showed the degradation of vegetation and water bodies in the marshes, as vast areas of natural vegetation and agricultural lands disappeared and were replaced with barren areas. The marshes were influenced by climatic change, including rising emperature and the diminishing amount of precipitation during 1981–2016.

    Fulltekst (pdf)
    fulltext
  • 23.
    Hashmi, Khurram Azeem
    et al.
    Department of Computer Science, Technical University, 67663 Kaiserslautern, Germany; Mindgarage, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany; German Research Institute for Artificial Intelligence (DFKI), 67663 Kaiserslautern, Germany.
    Pagani, Alain
    German Research Institute for Artificial Intelligence (DFKI), 67663 Kaiserslautern, Germany.
    Liwicki, Marcus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Stricker, Didier
    Department of Computer Science, Technical University, 67663 Kaiserslautern, Germany; German Research Institute for Artificial Intelligence (DFKI), 67663 Kaiserslautern, Germany.
    Afzal, Muhammad Zeshan
    Department of Computer Science, Technical University, 67663 Kaiserslautern, Germany; Mindgarage, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany; German Research Institute for Artificial Intelligence (DFKI), 67663 Kaiserslautern, Germany.
    Cascade Network with Deformable Composite Backbone for Formula Detection in Scanned Document Images2021Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 11, nr 16, artikkel-id 7610Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents a novel architecture for detecting mathematical formulas in document images, which is an important step for reliable information extraction in several domains. Recently, Cascade Mask R-CNN networks have been introduced to solve object detection in computer vision. In this paper, we suggest a couple of modifications to the existing Cascade Mask R-CNN architecture: First, the proposed network uses deformable convolutions instead of conventional convolutions in the backbone network to spot areas of interest better. Second, it uses a dual backbone of ResNeXt-101, having composite connections at the parallel stages. Finally, our proposed network is end-to-end trainable. We evaluate the proposed approach on the ICDAR-2017 POD and Marmot datasets. The proposed approach demonstrates state-of-the-art performance on ICDAR-2017 POD at a higher IoU threshold with an f1-score of 0.917, reducing the relative error by 7.8%. Moreover, we accomplished correct detection accuracy of 81.3% on embedded formulas on the Marmot dataset, which results in a relative error reduction of 30%.

    Fulltekst (pdf)
    fulltext
  • 24.
    Hatamzad, Mahshid
    et al.
    Department of Industrial Engineering, UiT/The Arctic University of Norway, Narvik, 8514 Nordland, Norway.
    Polanco Pinerez, Geanette Cleotilde
    Department of Industrial Engineering, UiT/The Arctic University of Norway, Narvik, 8514 Nordland, Norway.
    Casselgren, Johan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Using Deep Learning to Predict the Amount of Chemicals Applied on the Wheel Track for Winter Road Maintenance2022Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 12, nr 7, artikkel-id 3508Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The decade of big data has emerged in recent years, which has led to entering the era of intelligent transportation. One of the main challenges to deploying intelligent transportation is dealing with winter roads in cold climate countries. Different operations can be used to protect the road from ice and snow, such as spreading chemicals (here salt) on the road surface. Using salt for de-icing and anti-icing increases road safety. However, the excess use of salt must be avoided since it is not cost-efficient and has negative impacts on the environment. Therefore, the accurate and timely prediction of salt quantity for winter road maintenance helps decision support systems to achieve effective and efficient winter road maintenance. Thus, this paper performs exploratory data analysis to determine the relationships among variables to find the best prediction model for this problem. Due to the stochastic nature of variables regarding weather and roads, a deep neural network/deep learning is selected to predict the amount of salt on the wheel track, using historical data measured by sensors and road weather stations. The results show that the proposed model performs perfectly to learn and predict the amount of salt on the wheel track, based on different metrics, including the loss function, scatter plot, mean absolute error, and explained variance.

  • 25.
    Hedemalm, Emil
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik.
    Kor, Ah-Lian
    School of Built Environment, Engineering, and Computing, Leeds Beckett University, Leeds LS6 3QS, UK.
    Hallberg, Josef
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Andersson, Karl
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Pattinson, Colin
    School of Built Environment, Engineering, and Computing, Leeds Beckett University, Leeds LS6 3QS, UK.
    Chinnici, Marta
    ENEA, C.R. Casaccia, Energy Technologies Department, ICT Division, 00123 Rome, Italy.
    Application of Online Transportation Mode Recognition in Games2021Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 11, nr 19, artikkel-id 8901Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    It is widely accepted that human activities largely contribute to global emissions and thus, greatly impact climate change. Awareness promotion and adoption of green transportation mode could make a difference in the long term. To achieve behavioural change, we investigate the use of a persuasive game utilising online transportation mode recognition to afford bonuses and penalties to users based on their daily choices of transportation mode. To facilitate an easy identification of transportation mode, classification predictive models are built based on accelerometer and gyroscope historical data. Preliminary results show that the classification true-positive rate for recognising 10 different transportation classes can reach up to 95% when using a historical set (66% without). Results also reveal that the random tree classification model is a viable choice compared to random forest in terms of sustainability. Qualitative studies of the trained classifiers and measurements of Android-device gravity also raise several issues that could be addressed in future work. This research work could be enhanced through acceleration normalisation to improve device and user ambiguity.

    Fulltekst (pdf)
    fulltext
  • 26.
    Hendl, Julius
    et al.
    Institute of Materials Science, Technische Universität Dresden, Helmholtzstr. 7, 01069 Dresden, Germany; Fraunhofer—Institute for Material and Beam Technology (IWS—Dresden), Winterbergstraße 28, 01069 Dresden, Germany.
    Daubner, Sina
    Institute of Materials Science, Technische Universität Dresden, Helmholtzstr. 7, 01069 Dresden, Germany.
    Marquardt, Axel
    Institute of Materials Science, Technische Universität Dresden, Helmholtzstr. 7, 01069 Dresden, Germany; Fraunhofer—Institute for Material and Beam Technology (IWS—Dresden), Winterbergstraße 28, 01069 Dresden, Germany.
    Stepien, Lukas
    Fraunhofer—Institute for Material and Beam Technology (IWS—Dresden), Winterbergstraße 28, 01069 Dresden, Germany.
    Lopez, Elena
    Fraunhofer—Institute for Material and Beam Technology (IWS—Dresden), Winterbergstraße 28, 01069 Dresden, Germany.
    Brückner, Frank
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Produkt- och produktionsutveckling. Fraunhofer—Institute for Material and Beam Technology (IWS—Dresden), Winterbergstraße 28, 01069 Dresden, Germany.
    Leyens, Christoph
    Institute of Materials Science, Technische Universität Dresden, Helmholtzstr. 7, 01069 Dresden, Germany; Fraunhofer—Institute for Material and Beam Technology (IWS—Dresden), Winterbergstraße 28, 01069 Dresden, Germany.
    In Situ CT Tensile Testing of an Additively Manufactured and Heat-Treated Metastable ß-Titanium Alloy (Ti-5Al-5Mo-5V-3Cr)2021Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 11, nr 21, artikkel-id 9875Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Additive manufacturing has been considered a suitable process for developing high-performance parts of medical or aerospace industries. The electron beam powder bed fusion process, EB-PBF, is a powder bed fusion process carried out in a vacuum, in which the parts are melted using a highly focused electron beam. The material class of metastable β-titanium alloys, and especially Ti-5Al-5Mo-5V-3Cr, show great potential for use as small and highly complex load-bearing parts. Specimens were additively manufactured with optimised process parameters and different heat treatments used in order to create tailored mechanical properties. These heat-treated specimens were analysed with regard to their microstructure (SEM) and their mechanical strength (tensile testing). Furthermore, in situ tensile tests, using a Deben CT5000 and a YXLON ff35 industrial µ-CT, were performed and failure-critical defects were detected, analysed and monitored. Experimental results indicate that, if EB-PBF-manufactured Ti-5553 is heat-treated differently, a variety of mechanical properties are possible. Regarding their fracture mechanisms, failure-critical defects can be detected at different stages of the tensile test and defect growth behaviour can be analysed.

  • 27.
    Jin, Jie
    et al.
    Key Laboratory of Concrete and Prestressed Concrete Structures of Ministry of Education, National Engineering Research Center for Prestressing Technology, School of Civil Engineering, Southeast University, Nanjing 211189, China.
    Liu, Dongyun
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Tu, Yongming
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand. Key Laboratory of Concrete and Prestressed Concrete Structures of Ministry of Education, National Engineering Research Center for Prestressing Technology, School of Civil Engineering, Southeast University, Nanjing 211189, China.
    Numerical Simulation of Aerodynamic Pressure on Sound Barriers from High-Speed Trains with Different Nose Lengths2024Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 14, nr 7, artikkel-id 2898Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    For high-speed railway sound barriers, determining the aerodynamic pressure generated by high-speed trains is crucial for their structural design. This paper investigates the distribution of aerodynamic pressure on the sound barrier caused by high-speed trains with different nose lengths, utilizing the computational fluid dynamics (CFD) simulation method. The accuracy of the numerical simulation method employed is verified through comparison with field test results from the literature. Research findings reveal that when a high-speed train passes through a sound barrier, significant “head wave” and “wake wave” effects occur, with the pressure peak of the “head wave” being notably greater than that of the “wake wave”. As the distance between the sound barrier and the center of the train gradually increases, the aerodynamic pressure on the sound barrier gradually decreases. The nose length of the train has a considerable impact on the aerodynamic pressure exerted on the sound barrier. The streamlined shape of longer-nose trains can significantly reduce the aerodynamic effects on the sound barrier, resulting in a notably smaller pressure peak compared to shorter-nose trains. Finally, by establishing the relationship between the train nose length and the aerodynamic pressure peak, a calculation formula for the train-induced aerodynamic pressure acting on the sound barrier is proposed, taking into account the nose length of the high-speed train.

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  • 28.
    Joloudari, Javad Hassannataj
    et al.
    Department of Computer Engineering, Faculty of Engineering, University of Birjand, Birjand 9717434765, Iran.
    Marefat, Abdolreza
    Department of Artificial Intelligence, Technical and Engineering Faculty, South Tehran Branch, Islamic Azad University, Tehran 1477893780, Iran.
    Nematollahi, Mohammad Ali
    Department of Computer Sciences, Fasa University, Fasa 7461686131, Iran.
    Oyelere, Solomon Sunday
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Hussain, Sadiq
    Examination Branch, Dibrugarh University, Dibrugarh 786004, Assam, India.
    Effective Class-Imbalance Learning Based on SMOTE and Convolutional Neural Networks2023Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 13, nr 6, artikkel-id 4006Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Imbalanced Data (ID) is a problem that deters Machine Learning (ML) models from achieving satisfactory results. ID is the occurrence of a situation where the quantity of the samples belonging to one class outnumbers that of the other by a wide margin, making such models’ learning process biased towards the majority class. In recent years, to address this issue, several solutions have been put forward, which opt for either synthetically generating new data for the minority class or reducing the number of majority classes to balance the data. Hence, in this paper, we investigate the effectiveness of methods based on Deep Neural Networks (DNNs) and Convolutional Neural Networks (CNNs) mixed with a variety of well-known imbalanced data solutions meaning oversampling and undersampling. Then, we propose a CNN-based model in combination with SMOTE to effectively handle imbalanced data. To evaluate our methods, we have used KEEL, breast cancer, and Z-Alizadeh Sani datasets. In order to achieve reliable results, we conducted our experiments 100 times with randomly shuffled data distributions. The classification results demonstrate that the mixed Synthetic Minority Oversampling Technique (SMOTE)-Normalization-CNN outperforms different methodologies achieving 99.08% accuracy on the 24 imbalanced datasets. Therefore, the proposed mixed model can be applied to imbalanced binary classification problems on other real datasets.

    Fulltekst (pdf)
    fulltext
  • 29.
    Kanchi, Shrinidhi
    et al.
    Department of Computer Science, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany.
    Pagani, Alain
    German Research Institute for Artificial Intelligence (DFKI), 67663 Kaiserslautern, Germany.
    Mokayed, Hamam
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Liwicki, Marcus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Stricker, Didier
    Department of Computer Science, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany; German Research Institute for Artificial Intelligence (DFKI), 67663 Kaiserslautern, Germany.
    Afzal, Muhammad Zeshan
    Department of Computer Science, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany; German Research Institute for Artificial Intelligence (DFKI), 67663 Kaiserslautern, Germany; Mindgarage, Department of Computer Science, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany.
    EmmDocClassifier: Efficient Multimodal Document Image Classifier for Scarce Data2022Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 12, nr 3, artikkel-id 1457Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Document classification is one of the most critical steps in the document analysis pipeline. There are two types of approaches for document classification, known as image-based and multimodal approaches. Image-based document classification approaches are solely based on the inherent visual cues of the document images. In contrast, the multimodal approach co-learns the visual and textual features, and it has proved to be more effective. Nonetheless, these approaches require a huge amount of data. This paper presents a novel approach for document classification that works with a small amount of data and outperforms other approaches. The proposed approach incorporates a hierarchical attention network (HAN) for the textual stream and the EfficientNet-B0 for the image stream. The hierarchical attention network in the textual stream uses dynamic word embedding through fine-tuned BERT. HAN incorporates both the word level and sentence level features. While earlier approaches rely on training on a large corpus (RVL-CDIP), we show that our approach works with a small amount of data (Tobacco-3482). To this end, we trained the neural network at Tobacco-3482 from scratch. Therefore, we outperform the state-of-the-art by obtaining an accuracy of 90.3%. This results in a relative error reduction rate of 7.9%.

  • 30.
    Kim, Joo Chan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Laine, Teemu H.
    Department of Digital Media, Ajou University, Suwon 16499, Korea.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Multimodal Interaction Systems Based on Internet of Things and Augmented Reality: A Systematic Literature Review2021Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 11, nr 4, artikkel-id 1738Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Technology developments have expanded the diversity of interaction modalities that can be used by an agent (either a human or machine) to interact with a computer system. This expansion has created the need for more natural and user-friendly interfaces in order to achieve effective user experience and usability. More than one modality can be provided to an agent for interaction with a system to accomplish this goal, which is referred to as a multimodal interaction (MI) system. The Internet of Things (IoT) and augmented reality (AR) are popular technologies that allow interaction systems to combine the real-world context of the agent and immersive AR content. However, although MI systems have been extensively studied, there are only several studies that reviewed MI systems that used IoT and AR. Therefore, this paper presents an in-depth review of studies that proposed various MI systems utilizing IoT and AR. A total of 23 studies were identified and analyzed through a rigorous systematic literature review protocol. The results of our analysis of MI system architectures, the relationship between system components, input/output interaction modalities, and open research challenges are presented and discussed to summarize the findings and identify future research and development avenues for researchers and MI developers.

  • 31.
    Kim, Joo Chan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Saguna, Saguna
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    The Effects of Augmented Reality Companion on User Engagement in Energy Management Mobile App2024Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 14, nr 7, artikkel-id 2621Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    As the impact of global warming on climate change becomes noticeable, the importance of energy efficiency for reducing greenhouse gas emissions grows immense. To this end, a platform, solution, and mobile apps are developed as part of the European Union’s Horizon 2020 research and innovation program to support energy optimization in residences. However, to ensure long-term energy optimization, it is crucial to keep users engaged with the apps. Since augmented reality (AR) and a virtual animal companion positively influenced user engagement, we designed an AR companion that represented the user’s residence states; thereby making the user aware of indoor information. We conducted user evaluations to determine the effect of the AR companion on user engagement and perceived usability in the context of energy management. We identified that the user interface (UI) with AR (ARUI) barely affected user engagement and perceived usability compared to the traditional UI without AR (TUI); however, we found that the ARUI positively affected one of the user engagement aspects. Our results show AR companion integration’s potential benefits and effects on energy management mobile apps. Furthermore, our findings provide insights into UI design elements for developers considering multiple interaction modalities with AR.

    Fulltekst (pdf)
    fulltext
  • 32.
    Krikigianni, Eleni
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Matsakas, Leonidas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Rova, Ulrika
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Christakopoulos, Paul
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Patel, Alok
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Investigating the Bioconversion Potential of Volatile Fatty Acids: Use of Oleaginous Yeasts Rhodosporidium toruloides and Cryptococcus curvatus towards the Sustainable Production of Biodiesel and Odd-Chain Fatty Acids2022Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 12, nr 13, artikkel-id 6541Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Oleaginous yeasts have attracted increasing scientific interest as single cell oil (SCO) producers. SCO can be used as a fossil-free fuel substitute, but also as a source of rarely found odd-chain fatty acids (OCFAs), such as C15, C17, and C25 fatty acids which have a wide range of nutritional and biological applications. Volatile fatty acids (VFAs) have gained interest as sustainable carbon source for yeasts. This study aims to improve current knowledge on yeast species that yield high amounts of SCO using VFAs as a carbon source. Specifically, the growth of the promising yeasts Cryptococcus curvatus and Rhodotorula toruloides was evaluated on individual VFAs, such as acetic, propionic, and butyric acid. C. curvatus proved to be more tolerant in higher concentrations of VFAs (up to 60 g/L), while butyric acid favored biomass and lipid conversion (0.65 and 0.23 g/gsubstrate, respectively). For R. toruloides, butyric acid favored biomass conversion (0.48 g/gsubstrate), but lipid conversion was favored using acetic acid, instead (0.14 g/gsubstrate). Propionic acid induced the formation of OCFAs, which yielded higher amounts for C. curvatus (up to 2.17 g/L). VFAs derived from the anaerobic digestion of brewer’s spent grain were tested as a cost-competitive carbon source and illustrated the significance of the combination of different VFAs in the quality of the produced SCO, by improving the biodiesel properties and OCFAs production.

  • 33.
    Kyösti, Petter
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, ProcessIT Innovations R&D Centre.
    Lindström, John
    Dielcon AB, 954 41 S Sunderbyn, Sweden.
    SOA-Based Platform Use in Development and Operation of Automation Solutions: Challenges, Opportunities, and Supporting Pillars towards Emerging Trends2022Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 12, nr 3, artikkel-id 1074Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The paper which is based on a literature review combined with a case study, spanning manufacturing and process industry contexts, set out to determine whether there is an emerging trend to use a service-oriented architecture (SOA)-based platform supporting microservices while developing and operating automation solutions while also considering effects and implications. The results point out that there is a significant potential, during the lifecycle, to save significant engineering time/effort during the development-related and operations phases while integrating systems and adding new types of sensors or other equipment. In addition, the results indicate that there are also business development advantages when promoting an SOA-based architecture supporting microservices towards monolith architectures and that a cybersecurity baseline can be included as part of the platform baseline. However, there is a threshold, before the benefits can be reaped, in terms of the need to build up a competency and skills set concerning the platform, SOA and microservices, as many providers of automation solutions are still doing the development in a traditional old monolithic style with hard-coded integrations between components and systems. Finally, we see an emerging trend to use a competent SOA-based platform in the development and operation of automation solutions.

    Fulltekst (pdf)
    fulltext
  • 34.
    Lindström, John
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Hermansson, Anders
    Adage AB, C/O BnearIT.
    Blomstedt, Fredrik
    BnearIT AB.
    Kyösti, Petter
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    A multi-usable cloud service platform: a case study on improved development pace and efficiency2018Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 8, nr 2, artikkel-id 316Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The case study, spanning three contexts, concerns a multi-usable cloud service platform for big data collection and analytics and how the development pace and efficiency of it has been improved 50-75% by using the Arrowhead framework and changing development processes/practices. Further, additional results captured during the case study are related to technology, competencies and skills, organization, management, infrastructure, and service and support. A conclusion is that when offering a complex offer such as an Industrial Product-Service System, comprising sensors, hardware, communications, software, cloud service platform, etc., it is necessary that the technology, business model, business set up and organization all go hand in hand during the development and later operation, as all “components” are required for a successful result.

    Fulltekst (pdf)
    fulltext
  • 35.
    Lindström, John
    et al.
    Combitech AB, Varvsgatan 31 7tr, 972 36 Luleå, Sweden.
    Kyösti, Petter
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Birk, Wolfgang
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system. Predge AB, Varvsgatan 11, 972 36 Luleå, Sweden.
    Lejon, Erik
    Gestamp HardTech AB, 972 45 Luleå, Sweden.
    An Initial Model for Zero Defect Manufacturing2020Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 10, nr 13, artikkel-id 4570Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper investigates an initial model for Zero Defect Manufacturing (ZDM) using a cost function where the operation and condition of a production process are reflected, and the quality of the output/product and the production process (as well as safety aspects) can be considered. The outset of the study is based on empirical data collected from five manufacturing companies, and proposes an initial model for ZDM with an Industry 4.0 perspective. The initial ZDM model has a generic setup for a real-life system and its replication as a digital twin using system models based on a representation of a generic production process with its connected control system, and potential interconnections between unit processes. It is based on concepts from system theory of dynamic systems and principles from condition monitoring and fault detection. In that way the model is deemed as highly generalizable for manufacturing and process industry companies as well as for some critical infrastructures with production and distribution systems. The proposed model with its cost function setup is analyzed and discussed in the context of ZDM. It is concluded that production processes in the manufacturing and process industry can be made more intelligent and interoperable using this approach. Improved sustainability, competitiveness, efficiency and profitability of companies are foreseen welcomed secondary effects. Finally, the proposed ZDM model further develops the ZDM by adding to it a systematic approach based on a solid mathematical foundation.

    Fulltekst (pdf)
    fulltext
  • 36.
    Lotfian, Samira
    et al.
    Boliden Mineral AB, Boliden, Sweden.
    Lennartsson, Andreas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Jokilaakso, Ari
    School of Chemical Engineering, Department of Chemical and Metallurgical Engineering, Aalto University, Aalto, Finland.
    Sustainable Management of the Plastic-Rich Fraction of WEEE by Utilization as a Reducing Agent in Metallurgical Processes2019Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 9, nr 20, artikkel-id 4224Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In modern society, there is a fast growth in the production of electrical and electronic equipment (EEE); however, rapid growth results in the frequent discarding of this equipment. During the treatment of discarded materials, a stream is generated that contains a high fraction of plastic materials, but also metals and oxides. This stream, which is called shredder residue material (SRM), is heterogeneous, which limits its recycling options. Utilizing this material in metallurgical processes allows the plastic fraction to be used as a reductant and energy source and the metallic fraction to be recycled and returned to the production of EEE. The aim of this study was to evaluate the potential of plastic-containing materials, especially SRM, as alternative reductants in metallurgical processes. The first step was to compare the thermal conversion characteristics of plastic-containing materials to the currently used reducing agent, i.e., coal. Three main candidates, polyurethane (PUR), polyethylene (PE), and SRM, were studied using a drop tube furnace and an optical single-particle burner. PE had the highest volatile content and the fastest conversion time, whereas PUR had the longest conversion time. Thereafter, plastic materials were tested at the industrial scale through injection to the zinc fuming process at the Boliden Rönnskär smelter. During the industrial trial, the amount of coal that was injected was reduced and substituted with plastic material. The results indicate the possibility of reducing the coal injection rate in favor of partial substitution with plastic materials.

  • 37.
    Lugnet, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Digitala tjänster och system.
    Ericson, Åsa
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Digitala tjänster och system. Department of Industrial Engineering, UiT The Arctic University of Norway, NO-8514 Narvik, Norway.
    Larsson, Andreas
    Department of Mechanical Engineering, Blekinge Institute of Technology, SE-37179 Karlskrona, Sweden.
    Realization of Agile Methods in Established Processes: Challenges and Barriers2021Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 11, nr 5, artikkel-id 2043Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents an explorative study and the results of 17 interviews with informants from different companies. Its purpose is to identify the challenges associated with implementing agile methods along with the established procedures for early design. The study exemplifies project leaders’ experiences and implementation efforts. As leaders of design projects, they have proposed the use of a new method that involves teams engaging in testing and evaluation, which aids in the understanding and introduction of change initiatives. The challenges that are identified are as follows: (1) a lack of approval not only from top managers but also from critical peers; (2) an unprepared organization that did not allow teamwork; and (3) a lack of specific company success factors to support new methods.

    Fulltekst (pdf)
    fulltext
  • 38.
    Majerič, Matej
    et al.
    Faculty of Sport, University of Ljubljana, 1000 Ljubljana, Slovenia.
    Verdel, Nina
    Department of Health Sciences, Mid Sweden University, 831 25 Östersund, Sweden.
    Ogrin, Jan
    Faculty of Sport, University of Ljubljana, 1000 Ljubljana, Slovenia.
    Holmberg, Hans-Christer
    Luleå tekniska universitet, Institutionen för hälsa, lärande och teknik, Hälsa, medicin och rehabilitering. Department of Physiology and Pharmacology, Biomedicum C5, Karolinska Institute, 171 77 Stockholm, Sweden.
    Supej, Matej
    Faculty of Sport, University of Ljubljana, 1000 Ljubljana, Slovenia; Department of Health Sciences, Mid Sweden University, 831 25 Östersund, Sweden.
    Application of Experimental Measurements in a Wind Tunnel to the Development of a Model for Aerodynamic Drag on Elite Slalom and Giant Slalom Alpine Skiers2022Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 12, nr 2, artikkel-id 902Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Aerodynamic drag is a major cause of energy losses during alpine ski racing. Here we developed two models for monitoring the aerodynamic drag on elite alpine skiers in the technical disciplines. While 10 skiers assumed standard positions (high, middle, tuck) with exposure to different wind speeds (40, 60, and 80 km/h) in a wind tunnel, aerodynamic drag was assessed with a force plate, shoulder height with video-based kinematics, and cross-sectional area with interactive image segmentation. The two regression models developed had 3.9–7.7% coefficients of variation and 4.5–16.5% relative limits of agreement. The first was based on the product of the coefficient of aerodynamic drag and cross-sectional area (Cd·S) and the second on the coefficient of aerodynamic drag Cd and normalized cross-sectional area of the skier Sn, both expressed as a function of normalized shoulder height (hn). In addition, normative values for Cd (0.75 ± 0.09–1.17 ± 0.09), Sn (0.51 ± 0.03–0.99 ± 0.05), hn (0.48 ± 0.03–0.79 ± 0.02), and Cd·S (0.23 ± 0.03–0.66 ± 0.09 m2) were determined for the three different positions and wind speeds. Since the uncertainty in the determination of energy losses due to aerodynamic drag relative to total energy loss with these models is expected to be <2.5%, they provide a valuable tool for analysis of skiing performance.

  • 39.
    Malekkhouyan, Roya
    et al.
    Department of Chemical Engineering, Isfahan University of Technology, Isfahan 84156-83111, Iran.
    Nouri Khorasani, Saied
    Department of Chemical Engineering, Isfahan University of Technology, Isfahan 84156-83111, Iran.
    Esmaeely Neisiany, Rasoul
    Department of Materials and Polymer Engineering, Faculty of Engineering, Hakim Sabzevari University, Sabzevar 9617976487, Iran.
    Torkaman, Reza
    Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111, Iran.
    Koochaki, Mohammad Sadegh
    Department of Chemical Engineering, Isfahan University of Technology, Isfahan 84156-83111, Iran.
    Das, Oisik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Preparation and Characterization of Electrosprayed Nanocapsules Containing Coconut-Oil-Based Alkyd Resin for the Fabrication of Self-Healing Epoxy Coatings2020Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 10, nr 9, artikkel-id 3171Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the present study, the preparation of nanocapsules using the coaxial electrospraying method was investigated. Poly(styrene-co-acrylonitrile) (SAN) was used as a shell material and coconut-oil-based alkyd resin (CAR) as a core. Chemical structure, thermal stability, and morphology of nanocapsules were characterized by Fourier transform infrared (FTIR) spectroscopy, thermal gravimetric analysis (TGA), and field emission scanning electron microscopy (FE-SEM), respectively. In addition, the formation of the core–shell structure was approved by transmission electron microscopy (TEM) and FE-SEM micrographs of the fractured nanocapsules. Furthermore, differential scanning calorimetry tests (DSC) were carried out to investigate the reactivity of released healing agents from the nanocapsules. The prepared nanocapsules were then incorporated into the epoxy resins and applied on the surfaces of the steel panels. The effect of capsule incorporation on the properties of the coating was evaluated. The self-healing performance of the coatings in the salty and acidic media was also assessed. The FTIR results revealed the presence of both shell and core in the prepared nanocapsules and proved that no reaction occurred between them. The morphological studies confirmed that the electrosprayed nanocapsules’ mean diameter was 708 ± 252 nm with an average shell thickness of 82 nm. The TGA test demonstrated the thermal stability of nanocapsules to be up to 270 °C while the DSC results reveal a successful reaction between CAR and epoxy resin, especially in the acidic media. The electrochemical impedance spectroscopy (EIS) test results demonstrate that the best self-healing performance was achieved for the 2 and 1 wt.% nanocapsules incorporation in the NaCl, and HCl solution, respectively.

  • 40.
    Manh Do, Tan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Laue, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Mattsson, Hans
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Jia, Qi
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Numerical Analysis of an Upstream Tailings Dam Subjected to Pond Filling Rates2021Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 11, nr 13, artikkel-id 6044Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    One of the challenges in upstream tailings dam projects is to ensure the allowable rate of deposition of tailings in the pond (i.e., pond filling rate) while maintaining the stability of the dam. This is due to the fact that an upstream tailings dam is constructed by placing dikes on top of previously deposited soft tailings, which could lead to a decrease in dam stability because of the build-up of excess pore water pressure. The main purpose of this work is to investigate the effects of pond filling rates on excess pore water pressure and the stability of an upstream tailings dam by a numerical study. A finite element software was used to simulate the time-dependent pond filling process and staged dam construction under various pond filling rates. As a result, excess pore water pressure increased in each raising phase and decreased in the subsequent consolidation phase. However, some of the excess pore water pressure remained after every consolidation phase (i.e., the build-up of excess pore water pressure), which could lead to a potentially critical situation in the stability of the dam. In addition, the remaining excess pore water pressure varied depending on the pond filling rates, being larger for high filling rates and smaller for low filling rates. It is believed that the approach used in this study could be a guide for dam owners to keep a sufficiently high pond filling rate but still ensure the desirable stability of an upstream tailings dam.

    Fulltekst (pdf)
    Numerical Analysis of an Upstream Tailings Dam Subjected to Pond Filling Rates
  • 41.
    Martinec, Tomislav
    et al.
    Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, 10000 Zagreb, Croatia.
    Škec, Stanko
    Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, 10000 Zagreb, Croatia.
    Perišić, Marija Majda
    Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, 10000 Zagreb, Croatia.
    Štorga, Mario
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Människa och teknik. Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, 10000 Zagreb, Croatia.
    Revisiting Problem-Solution Co-Evolution in the Context of Team Conceptual Design Activity2020Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 10, nr 18, artikkel-id 6303Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The conventional prescriptive and descriptive models of design typically decompose the overall design process into elementary processes, such as analysis, synthesis, and evaluation. This study revisits some of the assumptions established by these models and investigates whether they can also be applied for modelling of problem-solution co-evolution patterns that appear during team conceptual design activities. The first set of assumptions concerns the relationship between performing analysis, synthesis, and evaluation and exploring the problem and solution space. The second set concerns the dominant sequences of analysis, synthesis, and evaluation, whereas the third set concerns the nature of transitions between the problem and solution space. The assumptions were empirically tested as part of a protocol analysis study of team ideation and concept review activities. Besides revealing inconsistencies in how analysis, synthesis, and evaluation are defined and interpreted across the literature, the study demonstrates co-evolution patterns, which cannot be described by the conventional models. It highlights the important role of analysis-synthesis cycles during both divergent and convergent activities, which is co-evolution and refinement, respectively. The findings are summarised in the form of a model of the increase in the number of new problem and solution entities as the conceptual design phase progresses, with implications for both design research and design education.

    Fulltekst (pdf)
    fulltext
  • 42.
    Martinetti, Alberto
    et al.
    Design, Production and Management Department, University of Twente, Enschede, The Netherlands.
    Costa Marques, Henrique
    Logistics Engineering Laboratory, Aeronautics Institute of Technology, São José dos Campos, Brazil.
    Singh, Sarbjeet
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    van Dongen, Leo
    Design, Production and Management Department, University of Twente, Enschede, The Netherlands.
    Reflections on the Limited Pervasiveness of Augmented Reality in Industrial Sectors2019Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 9, nr 16, artikkel-id 3382Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The paper aims to investigate the reasons why Augmented Reality (AR) has not fully broken the industrial market yet, or found a wider application in industries. The main research question the paper tries to answer is: what are the factors (and to what extent) that are limiting AR? Firstly, a reflection on the state of art of AR applications in industries is proposed, to discover the sectors more commonly chosen for deploying the technology so far. Later, based on a survey conducted after that, three AR applications have been tested on manufacturing, automotive, and railway sectors, and the paper pinpoints key aspects that are conditioning its embedding in the daily working life. In order to compare whether the perception of employees from railway, automotive, and manufacturing sectors differs significantly, a one-way analysis of variance (ANOVA) has been used. Later, suggestions are formulated in order to improve these aspects in the industry world. Finally, the paper indicates the main conclusions, highlighting possible future researches to start.

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  • 43.
    Minami, Ichiro
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Molecular science of lubricant additives2017Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 7, nr 5, artikkel-id 445Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This review aims at introducing an engineering field of lubrication to researchers who are not familiar with tribology, thereby emphasizing the importance of lubricant chemistry in applied science. It provides initial guidance regarding additive chemistry in lubrication systems for researchers with different backgrounds. The readers will be introduced to molecular sciences underlying lubrication engineering. Currently, lubricant chemistry, especially "additive technology", looks like a very complicated field. It seems that scientific information is not always shared by researchers. The cause of this is that lubrication engineering is based on empirical methods and focuses on market requirements. In this regard, engineering knowhow is held by individuals and is not being disclosed to scientific communities. Under these circumstances, a bird's-eye view of lubricant chemistry in scientific words is necessary. The novelty of this review is to concisely explain the whole picture of additive technology in chemical terms. The roles and functions of additives as the leading actors in lubrication systems are highlighted within the scope of molecular science. First, I give an overview of the fundamental lubrication model and the role of lubricants in machine operations. The existing additives are categorized by the role and work mechanism in lubrication system. Examples of additives are shown with representative molecular structure. The second half of this review explains the scientific background of the lubrication engineering. It includes interactions of different components in lubrication systems. Finally, this review predicts the technical trends in lubricant chemistry and requirements in molecular science. This review does not aim to be a comprehensive chart or present manufacturing knowhow in lubrication engineering. References were carefully selected and cited to extract "the most common opinion" in lubricant chemistry and therefore many engineering articles were omitted for conciseness

  • 44.
    Mishra, Shashank
    et al.
    Department of Computer Science, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany.
    Hashmi, Khurram Azeem
    Department of Computer Science, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany; Mindgarage, Department of Computer Science, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany; German Research Institute for Artificial Intelligence (DFKI), 67663 Kaiserslautern, Germany.
    Pagani, Alain
    German Research Institute for Artificial Intelligence (DFKI), 67663 Kaiserslautern, Germany.
    Liwicki, Marcus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Stricker, Didier
    Department of Computer Science, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany; German Research Institute for Artificial Intelligence (DFKI), 67663 Kaiserslautern, Germany.
    Afzal, Muhammad Zeshan
    Department of Computer Science, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany; Mindgarage, Department of Computer Science, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany; German Research Institute for Artificial Intelligence (DFKI), 67663 Kaiserslautern, Germany.
    Towards Robust Object Detection in Floor Plan Images: A Data Augmentation Approach2021Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 11, nr 23, artikkel-id 11174Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Object detection is one of the most critical tasks in the field of Computer vision. This task comprises identifying and localizing an object in the image. Architectural floor plans represent the layout of buildings and apartments. The floor plans consist of walls, windows, stairs, and other furniture objects. While recognizing floor plan objects is straightforward for humans, automatically processing floor plans and recognizing objects is challenging. In this work, we investigate the performance of the recently introduced Cascade Mask R-CNN network to solve object detection in floor plan images. Furthermore, we experimentally establish that deformable convolution works better than conventional convolutions in the proposed framework. Prior datasets for object detection in floor plan images are either publicly unavailable or contain few samples. We introduce SFPI, a novel synthetic floor plan dataset consisting of 10,000 images to address this issue. Our proposed method conveniently exceeds the previous state-of-the-art results on the SESYD dataset with an mAP of 98.1%. Moreover, it sets impressive baseline results on our novel SFPI dataset with an mAP of 99.8%. We believe that introducing the modern dataset enables the researcher to enhance the research in this domain.

  • 45.
    Naik, Shivam
    et al.
    Department of Computer Science, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany.
    Hashmi, Khurram Azeem
    Department of Computer Science, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany; Mindgarage, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany; German Research Institute for Artificial Intelligence (DFKI), 67663 Kaiserslautern, Germany.
    Pagani, Alain
    German Research Institute for Artificial Intelligence (DFKI), 67663 Kaiserslautern, Germany.
    Liwicki, Marcus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Stricker, Didier
    Department of Computer Science, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany; German Research Institute for Artificial Intelligence (DFKI), 67663 Kaiserslautern, Germany.
    Afzal, Muhammad Zeshan
    Department of Computer Science, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany; Mindgarage, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany; German Research Institute for Artificial Intelligence (DFKI), 67663 Kaiserslautern, Germany.
    Investigating Attention Mechanism for Page Object Detection in Document Images2022Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 12, nr 15, artikkel-id 7486Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Page object detection in scanned document images is a complex task due to varying document layouts and diverse page objects. In the past, traditional methods such as Optical Character Recognition (OCR)-based techniques have been employed to extract textual information. However, these methods fail to comprehend complex page objects such as tables and figures. This paper addresses the localization problem and classification of graphical objects that visually summarize vital information in documents. Furthermore, this work examines the benefit of incorporating attention mechanisms in different object detection networks to perform page object detection on scanned document images. The model is designed with a Pytorch-based framework called Detectron2. The proposed pipelines can be optimized end-to-end and exhaustively evaluated on publicly available datasets such as DocBank, PublayNet, and IIIT-AR-13K. The achieved results reflect the effectiveness of incorporating the attention mechanism for page object detection in documents.

  • 46.
    Nazir, Danish
    et al.
    Department of Computer Science, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany; Mindgarage, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany.
    Hashmi, Khurram Azeem
    Department of Computer Science, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany; Mindgarage, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany; German Research Institute for Artificial Intelligence (DFKI), 67663 Kaiserslautern, Germany.
    Pagani, Alain
    German Research Institute for Artificial Intelligence (DFKI), 67663 Kaiserslautern, Germany.
    Liwicki, Marcus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Stricker, Didier
    Department of Computer Science, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany; German Research Institute for Artificial Intelligence (DFKI), 67663 Kaiserslautern, Germany.
    Afzal, Muhammad Zeshan
    Department of Computer Science, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany; Mindgarage, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany; German Research Institute for Artificial Intelligence (DFKI), 67663 Kaiserslautern, Germany.
    HybridTabNet: Towards Better Table Detection in Scanned Document Images2021Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 11, nr 18, artikkel-id 8396Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Tables in document images are an important entity since they contain crucial information. Therefore, accurate table detection can significantly improve the information extraction from documents. In this work, we present a novel end-to-end trainable pipeline, HybridTabNet, for table detection in scanned document images. Our two-stage table detector uses the ResNeXt-101 backbone for feature extraction and Hybrid Task Cascade (HTC) to localize the tables in scanned document images. Moreover, we replace conventional convolutions with deformable convolutions in the backbone network. This enables our network to detect tables of arbitrary layouts precisely. We evaluate our approach comprehensively on ICDAR-13, ICDAR-17 POD, ICDAR-19, TableBank, Marmot, and UNLV. Apart from the ICDAR-17 POD dataset, our proposed HybridTabNet outperformed earlier state-of-the-art results without depending on pre- and post-processing steps. Furthermore, to investigate how the proposed method generalizes unseen data, we conduct an exhaustive leave-one-out-evaluation. In comparison to prior state-of-the-art results, our method reduced the relative error by 27.57% on ICDAR-2019-TrackA-Modern, 42.64% on TableBank (Latex), 41.33% on TableBank (Word), 55.73% on TableBank (Latex + Word), 10% on Marmot, and 9.67% on the UNLV dataset. The achieved results reflect the superior performance of the proposed method.

  • 47.
    Nguyen, Phong Tung
    et al.
    Vietnam Academy for Water Resources, Hanoi 100000, Vietnam.
    Ha, Duong Hai
    Institute for Water and Environment, Hanoi 100000, Vietnam.
    Avand, Mohammadtaghi
    Department of Watershed Management Engineering, College of Natural Resources, TarbiatModares University, Tehran, P.O. Box 14115-111, Iran.
    Jaafari, Abolfazl
    Research Institute of Forests and Rangelands, Agricultural Research, Education, and Extension Organization (AREEO), P.O. Box 64414-356, Tehran, Iran.
    Nguyen, Huu Duy
    Faculty of Geography, VNU University of Science, Vietnam National University, 334 Nguyen Trai, Hanoi 100000, Vietnam.
    Al-Ansari, Nadhir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Phong, Tran Van
    Institute of Geological Sciences, Vietnam Academy of Sciences and Technology, 84 Chua Lang Street, Dong da, Hanoi 100000, Vietnam.
    Sharma, Rohit
    Department of Electronics & Communication Engineering, SRM Institute of Science and Technology, Ghaziabad 201204, India.
    Kumar, Raghvendra
    Department of Computer Science and Engineering, GIET University, Gunupur 765022, India.
    Le, Hiep Van
    University of Transport Technology, Hanoi 100000, Vietnam.
    Ho, Lanh Si
    Institute of Research and Development, Duy Tan University, Da Nang 550000, Vietnam.
    Prakash, Indra
    Department of Science & Technology, Bhaskarcharya Institute for Space Applications and Geo-Informatics (BISAG), Government of Gujarat, Gandhinagar 382002, India.
    Pham, Binh Thai
    University of Transport Technology, Hanoi 100000, Vietnam.
    Soft Computing Ensemble Models Based on Logistic Regression for Groundwater Potential Mapping2020Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 10, nr 7, artikkel-id 2469Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Groundwater potential maps are one of the most important tools for the management of groundwater storage resources. In this study, we proposed four ensemble soft computing models based on logistic regression (LR) combined with the dagging (DLR), bagging (BLR), random subspace (RSSLR), and cascade generalization (CGLR) ensemble techniques for groundwater potential mapping in Dak Lak Province, Vietnam. A suite of well yield data and twelve geo-environmental factors (aspect, elevation, slope, curvature, Sediment Transport Index, Topographic Wetness Index, flow direction, rainfall, river density, soil, land use, and geology) were used for generating the training and validation datasets required for the building and validation of the models. Based on the area under the receiver operating characteristic curve (AUC) and several other validation methods (negative predictive value, positive predictive value, root mean square error, accuracy, sensitivity, specificity, and Kappa), it was revealed that all four ensemble learning techniques were successful in enhancing the validation performance of the base LR model. The ensemble DLR model (AUC = 0.77) was the most successful model in identifying the groundwater potential zones in the study area, followed by the RSSLR (AUC = 0.744), BLR (AUC = 0.735), CGLR (AUC = 0.715), and single LR model (AUC = 0.71), respectively. The models developed in this study and the resulting potential maps can assist decision-makers in the development of effective adaptive groundwater management plans.

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    fulltext
  • 48.
    Nhu, Viet-Ha
    et al.
    Geographic Information Science Research Group, Ton Duc Thang University, Ho Chi Minh City 700000, Vietnam. Faculty of Environment and Labour Safety, Ton Duc Thang University, Ho Chi Minh City 700000, Vietnam .
    Zandi, Danesh
    Department of Geomorphology, Faculty of Natural Resources, University of Kurdistan, Sanandaj 66177-15175, Iran.
    Shahabi, Himan
    Department of Geomorphology, Faculty of Natural Resources, University of Kurdistan, Sanandaj 66177-15175, Iran. Department of Zrebar Lake Environmental Research, Kurdistan Studies Institute, University of Kurdistan, Sanandaj 66177-15175, Iran.
    Chapi, Kamran
    Department of Rangeland and Watershed Management, Faculty of Natural Resources, University of Kurdistan, Sanandaj 66177-15175, Iran.
    Shirzadi, Ataollah
    Department of Rangeland and Watershed Management, Faculty of Natural Resources, University of Kurdistan, Sanandaj 66177-15175, Iran.
    Al-Ansari, Nadhir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Singh, Sushant K.
    Virtusa Corporation, 10 Marshall Street, Irvington, NJ 07111, USA.
    Dou, Jie
    Department of Civil and Environmental Engineering, Nagaoka University of Technology, 1603-1, Kami-Tomioka, Nagaoka, Niigata 940-2188, Japan.
    Nguyen, Hoang
    Institute of Research and Development, Duy Tan University, Da Nang 550000, Vietnam.
    Comparison of Support Vector Machine, Bayesian Logistic Regression, and Alternating Decision Tree Algorithms for Shallow Landslide Susceptibility Mapping along a Mountainous Road in the West of Iran2020Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 10, nr 15, artikkel-id 5047Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper aims to apply and compare the performance of the three machine learningalgorithms–support vector machine (SVM), bayesian logistic regression (BLR), and alternatingdecision tree (ADTree)–to map landslide susceptibility along the mountainous road of the SalavatAbad saddle, Kurdistan province, Iran. We identified 66 shallow landslide locations, based on fieldsurveys, by recording the locations of the landslides by a global position System (GPS), Google Earthimagery and black-and-white aerial photographs (scale 1: 20,000) and 19 landslide conditioningfactors, then tested these factors using the information gain ratio (IGR) technique. We checked thevalidity of the models using statistical metrics, including sensitivity, specificity, accuracy, kappa,root mean square error (RMSE), and area under the receiver operating characteristic curve (AUC).We found that, although all three machine learning algorithms yielded excellent performance, theSVM algorithm (AUC=0.984) slightly outperformed the BLR (AUC=0.980), and ADTree (AUC=0.977) algorithms. We observed that not only all three algorithms are useful and effective tools foridentifying shallow landslide-prone areas but also the BLR algorithm can be used such as the SVMalgorithm as a soft computing benchmark algorithm to check the performance of the models in future.

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  • 49.
    Nieto-Peroy, Cristóbal
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Emami, Reza
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik. Aerospace Mechatronics Group, University of Toronto Institute for Aerospace Studies, Toronto, ON, Canada.
    CubeSat Mission: From Design to Operation2019Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 9, nr 15, artikkel-id 3110Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The current success rate of CubeSat missions, particularly for first-time developers, may discourage non-profit organizations to start new projects. CubeSat development teams may not be able to dedicate the resources that are necessary to maintain Quality Assurance as it is performed for the reliable conventional satellite projects. This paper discusses the structured life-cycle of a CubeSat project, using as a reference the authors’ recent experience of developing and operating a 2U CubeSat, called qbee50-LTU-OC, as part of the QB50 mission. This paper also provides a critique of some of the current poor practices and methodologies while carrying out CubeSat projects.

    Fulltekst (pdf)
    fulltext
  • 50.
    Nunes, Lina
    et al.
    Structures Department, National Laboratory for Civil Engineering, Av. do Brasil, 101, 1700-066 Lisbon, Portugal; CE3C, Centre for Ecology, Evolution and Environmental Changes & CHANGE, Global Change and Sustainability Institute, University of the Azores, 9700-042 Angra do Heroísmo, Portugal.
    Duarte, Sónia
    Structures Department, National Laboratory for Civil Engineering, Av. do Brasil, 101, 1700-066 Lisbon, Portugal.
    Parracha, João L.
    Structures Department, National Laboratory for Civil Engineering, Av. do Brasil, 101, 1700-066 Lisbon, Portugal; Buildings Department, National Laboratory for Civil Engineering, Av. do Brasil, 101, 1700-066 Lisbon, Portugal; CERIS—Civil Engineering Research and Innovation for Sustainability, Instituto Superior Técnico, University of Lisbon, Av. Rovisco Pais, 1049-001 Lisbon, Portugal.
    Jones, Dennis
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Paulmier, Ivan
    Institut Technologique FCBA, Allée de Boutaut BP227, 33000 Bordeaux, France.
    Kutnik, Magdalena
    Elicit Plant, Le Châtaignier, 16220 Moulins-sur-Tardoire, France.
    Insulation Materials Susceptibility to Biological Degradation Agents: Molds and Subterranean Termites2023Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 13, nr 20, artikkel-id 11311Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Insulation materials are fundamental for decreasing energy losses and guaranteeing thermal and acoustic comfort in buildings, which may significantly contribute to decreasing the energy consumption related with poor thermal building conditions. These insulation materials should have a low susceptibility to biological degradation agents to decrease the risks of degradation of other construction materials, as well as decrease possible health risks related with the development of noxious biological degradation agents regarding indoor air quality, for example, or decrease possible structural risks posed by those agents. The present study aimed at evaluating the susceptibility of several insulation materials to mold growth and subterranean termites’ attack. Insulation materials, including expanded polystyrene (EPS), mineral wool (MW), and expanded cork agglomerate (ICB), were tested against mold development, using maritime pine as a control. Three types of inoculations were made: (1) natural indoor inoculation; (2) artificial inoculation using Aspergillus niger and Penicillium funiculosum; and (3) artificial inoculation using Aureobasidium pullulans. The susceptibility of the insulation materials referred to, plus wood/glass fiber (WGF), was evaluated for two subterranean termite species: Reticulitermes grassei and Reticulitermes flavipes. The expanded cork agglomerate showed a higher susceptibility to molds than the other insulation materials tested. The remaining materials revealed a good performance, showing no growth or traces of growth of molds. All the materials tested showed susceptibility to subterranean termites, with both species being able to cross them to obtain access to the wood. However, wood/glass fiber showed a negative effect, which translated into lower survival rates and attack degrees of the wood. Some tested materials showed a good resistance to the development of biological degradation agents, namely an organic material (coconut fiber), a composite of organic and inorganic materials (WGF), and an inorganic material (EPS). These results indicate that it is possible to pursue the development of innovative and effective insulation materials with a low susceptibility to biological degradation agents, regardless of their organic or inorganic origin.

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