2 37 - 75 of 75
rss atomLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
  • Edman, Jennifer
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Deriving characteristics of thin cirrus clouds from observations with the IRF lidar2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Cirrus clouds play an important role in radiative transfer, and thus have impact on the energy balance of the atmosphere and the climate of the Earth. Furthermore, they occur often and cover large areas globally at any time. Nevertheless, cirrus clouds are poorly studied, especially in the polar regions. Cirrus clouds are present in a large amount of the 14 years of data produced by the lidar at the Swedish Institude of Space Physics (IRF), but has not been studied to a large extent. A lidar is an active remote sensing instrument using a laser. This master's thesis develops and improves programs for analysis of cirrus clouds from this lidar data. It also performs analysis of six case studies chosen from the available data, and statistics of these six cases.

    The parameters calculated for each date are the cloud top, base and mean altitude, the geometrical thickness, the depolarisation ratio, the backscatter ratio (BSR), the backscatter coefficient, the extinction coefficient, the optical thickness and the number of cloud layers. No clear correlation between the optical thickness and the cloud top, base or mean altitude was found. There seems to be a weak correlation between increased optical thickness and increased geometrical thickness, which is not unreasonable. The mean cloud layer top altitude was 11.82 km and the mean cloud base was 10.36 km. The mean optical thickness for a cloud layer was 1.46 km, and the average of the cloud layer mean altitude was 11.09 km. It should be noted that the statistical analysis is based on only six cases with a total observation time of no more than 37 hours. A far larger dataset is needed in order to obtain any statistically signicant conclusions. The effect of averaging is studied, and it is concluded that averaging over altitude reduced the noise and facilitated the interpolation more than averaging over time did.

    Different approaches to obtain the molecular backscatter coefficient are compared, as well as the effect on the simulated molecular signal. Two of these approaches calculate the molecular backscatter coeffcient with input of the temperature and pressure either as continuously measured ground vales from the weather station at IRF or as radiosonde profiles for a specific time. In the other two, the molecular backscatter coeffcient is obtained from ECMWF data and from the standard atmosphere. Differences in the range 12-35% between the methods are found.

    Different approaches to calculate the backscatter ratio (BSR) are also compared. At cirrus altitudes, the decrease in the signal due to the molecular cloudfree part of the atmosphere is still strong, and finding the top and base separately by comparison with the standard deviation of the signal is proven a better method than interpolating between the point where the signal starts to increase and the point where it reaches the same signal value again. Height-normalising the signal provides a more robust method.

    For thin cirrus, the signal is not significantly attenuated above the cloud layer, and it is found that a method based on the ratios between the measured signal and the simulated molecular signal at cloud top and base did not produce reliable results for the optical thickness.

    In addition to analysing data and data processing methods, new data processing tools in MATLAB have been developed and existing functions have been improved. These will be valuable for continued studies with the IRF lidar, for cirrus as well as PSCs and thick and/or low-altitude clouds.

  • Tneh, Shao Heung
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Feasibility Study on Implementing IVF Hardware to Achieve Human Reproduction in Space2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • Faizi, Ana
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Information Security Risk Assessment in Cloud2019Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This research addresses the issue of information security risk assessment (ISRA) on cloud solutions implemented for large companies. Four companies were studied, of which three used cloud services and conducted ISRA, while one provided cloud services and consultancy to customers on ISRA. Data were gathered qualitatively to (1) analyze the cloud using companies’ practices and (2) to identify regularities observed by the cloud providing company. The COAT-hanger model, which focuses on theorizing the practices, was used to study the practices. The results showed that the companies aimed to follow the guidelines, in the form of frameworks or their own experience, to conduct ISRA; furthermore, the frameworks were altered to fit the companies’ needs. The results further indicated that one of the main concerns with the cloud ISRA was the absence of a culture that integrates risk management. In addition, the companies’ boards lacked interest in and/or awareness of risks associated with the cloud solutions. Finally, the finding also stressed the importance of a good understanding and a well written legal contract between the cloud providers and the companies utilizing the cloud services.

  • Åberg, Daniel
    Luleå University of Technology, Department of Arts, Communication and Education.
    Lärandet som bara hänger på väggen: En studie om musikens närvaro i skolan och fritidshemet ur ett sociokulturellt perspektiv2019Independent thesis Advanced level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The aim of this study was to investigate why musical instruments are not used more freely and frequently during activities as recess or at the after-school centres. A survey was executed among primary school staff in Piteå municipality, Sweden. The survey addressed past experience of musical activities, interest in music as well as individual extent of musical education. Participants were further asked to give a recollection of the accessibility of musical instruments in their workplace and eventually to reflect upon how satisfied they were with current accessibilities and work procedures considering the use of musical instruments. The outcome of the survey shows that there is a high accessibility of musical instruments in the primary school organization of Piteå municipality and that elementary teachers, as well as after-school centre teachers, often have formal musical education in their professional training. Despite these seemingly good conditions regarding musical practice, music is still treated differently from other topics and school activities. This could indicate that there are other elements, apart from actual musical competence, that are the source of these misconceptions and insecurities concerning musical instruments. One such element could be the individual experience of musical training and views on musical competence mediated within former teacher-student relations. Other elements include discourse and social structures within the teaching community, connected to views in larger society on culture and musicality, that could be the real cause of musical instruments not being used outside of musical classes. This study raises the question of what is to be prioritized in the school system. Should music teachers still be the only ones “allowed” to play instruments? Or should school staff put aside their own opinions and insecurities so that children may have a rich learning experience in music which further promotes development and progress?

  • Öhman, Julia
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences.
    Att trivas på sitt arbete: En kvalitativ studie om soldater och officerares upplevelser av arbetsplatsen2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A job is not only an economic factor for the individual; the work also has a great impact on the individual's well-being. It is therefore a prerequisite for employees to be happy at work, which places demands on the workplace. The purpose of the study is to investigate what soldiers and officers have for experiences of job satisfaction. This is answered by studying a specific company on an aircraft fleet within the Swedish Armed Forces based on these research questions: How do the informants experience their work situation at the company? What difficulties and opportunities can be identified based on the informants' work situation and how can these be understood? The thesis is based on a qualitative method and the empirical data has been collected through interviews with four officers and four soldiers. The theoretical framework is based on previous research on employees and job satisfaction, Herzberg's two-stage model and Karasek and Theorell's demand- control-support model. The results of the study show that both the soldiers and the officers feel that the high workload of the company causes the work situation to be perceived as worse. The informants also feel that they do not get paid for the work they do, that the workload prevents them from developing, that everyone does not get feedback in the way they had wanted and that the goals and requirements that are set for the function sometimes are too unclear. Furthermore, the results show that the officers and soldiers generally agree on how well-being is generally experienced at the company. The main difference between the soldiers and the officers is that the soldiers feel that their work situation is affected for the worse because they do not have the same powers to make decisions within the organization. What the informants especially feel is contributing to a more pleasant work situation is the good cohesion between the employees. The informants feel that their work situation is affected to a lesser extent by a number of aspects, but nevertheless the majority of the informants want to continue working at the company.

  • Hari Krishnan, Prem Kumar
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Design and Analysis of a Dynamic SpaceWire Routing Protocol for Reconfigurable and Distributed On-Board Computing Systems2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Future spacecrafts will require more computational and processing power to keep up with the growing demand in requirements and complexity. ScOSA is the next generation on-board computer developed by the German Aerospace Centre (DLR). The main motivation behind ScOSA is to replace the conventional on-board computer with distributed and reconfigurable computing nodes which provides higher performance, reliability, availability and stability by using a combination of the COTS components and reliable computing processors that are space qualified. In the current ScOSA system reconfiguration and routing of data between nodes are based on a static decision graph. SpaceWire protocol is used to communicate between nodes to provide reliability. The focus of the thesis is to design and implement a dynamic routing protocol for ScOSA which can be used in future for not only communicating between the nodes but also for reconfiguration. SpaceWire IPC is a customized protocol developed by DLR to provide communication between the nodes in a distributed network and to support monitoring, management and reconfiguration services. The dynamic routing protocol proposed in this thesis is primarily derived from the monitoring mechanism used in the SpaceWire IPC. PULL type monitoring mechanism is modelled and simulated using OMNeT++. The results obtained provide a qualitative outlook of the dynamic routing protocol implemented.

  • Högberg, Robert
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Arrowhead Framework Database System for Storage and Retrieval of Vehicle Signals2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Logging data is important in the digital world, both in the present and in the future. Using a database is a common way to store and retrieve data. Database prosumer system is a concept that may be the solution to many of the problems regarding data logging in the fourth industrial revolution.

    Earth-moving machines are evolving to being automatically operated, which demands scalable means for data management. Several software systems are needed to achieve a solution of this sort. A system to collect sensor data from the actual machine, a system to store the data and retrieve it, and systems that analyze, predict and actuate on that data.

    This thesis has its focus on storage and retrival of vehicle signal data, by implementing a Database system with the ability of easy update, adaptation and reuse in mind (quality attributes). The Arrowhead Framework, based on Service Oriented Architecture, is designed to handle communication between heterogeneous systems with cybersecurity. The first objective was to investigate if the Arrowhead Framework could guide towards a solution of the system, with the quality attributes in mind. The second objective was to examine what the consequences regarding batching data points to a database could be. InfluxDB and MongoDB are the databases used during the test.

    The Database System is implemented in Java containing four different modules. Client Common which holds necessary Arrowhead Framework resources. The Database Module, responsible for all database related functionality. The Database Provider which provides services regarding access of sensor data, and the Database Consumer responsible for collecting sensor data from different provider system(s).

    The system was tested by consuming a service at a Can Bus Provider, which is polling RPM data from a car. The rpm data is then stored in the implemented database. The test indicated that Arrowhead Framework can provide such a solution to achieve easy update, adaptation and reuse, on a small scale, old and in some cases non-existent documentation of the framework is holding the practical usage back.

    The result of batching data points concluded that the performance of InfluxDB writing operation improves with data point batching regards to performance, by writing several data points at once. MongoDB was not affected in the same way as InfluxDB, due to its fast single writing operation.

  • Jansson Högberg, Johan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Data Acquisition using Arrowhead Framework for Condition Based Maintenance of Industrial Equipment2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    As Industry 4.0 and Internet of Things are established across factories and enterprises, the interest for learning more about these concepts and the possibilities they provide for condition based maintenance is expressed by a factory in Sweden. By addressing the aspects of Internet of Things and Industry 4.0, a system for performing data acquisition from sensors in an industrial environment is developed using Arrowhead Framework. This framework is evaluated around its suitability for this kind of application, and regarding what the framework may provide to the factory compared to other solutions and systems. A solution featuring a system based on Arrowhead Framework is developed, implemented, and briefly tested. The system is successful in performing data acquisition, and Arrowhead Framework is considered a viable option that may be used to provide a system tailored for different purposes, presumed that the factory is prepared to allocate resources on developing a solution around it.

  • Lubbad, Manas
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences.
    Kriterierna för lämplig vårdnadshavare: En studie i samband med inkorporeringen av bankonventionen i svensk rätt2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • Martinez Cano, Pablo
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Thermomechanical Design and Analysis of the Lisa Phase Measurement System2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Gravitational Waves (GWs) are ripples in the curvature of spacetime that propagate as waves at the speed of light while travelling basically undisturbed from the moment of their creation by accelerated masses. GWs provide unique information about astrophysical sources, such as binary systems, allowing their exploration under a wide range of masses, mass ratios and physical states inaccessible otherwise and therefore opening a new window to observe the universe. The Laser Interferometry Space Antenna (LISA) mission will be a spaceborne gravitational wave observatory that is expected to be launched in 2034. The observatory will operate a near-equilateral triangle constellation of three spacecraft in formation flying around the Sun with Earth-like orbits. The observatory will establish, for the first time, a huge laser interferometer of three arms separated by 2.5 million km at pm/ p H z sensitivity, allowing detection of GW signals in the low-frequencies (mHz) regime. Using technology proven by LISA Pathfinder and GRACE-Follow on mission, the LISA metrology system will continuously operate heterodyne laser interferometers in order to measure the stretching and squeezing of space-time coupled onto their laser links as pm-level pathlength displacements and recorded as tiny µ-cycle phase fluctuations over thousands of seconds by an on-board instrument so-called Phase Measurement System (PMS) or shortly "Phasemeter”. This master thesis investigates the thermo-mechanical design of an engineering model, currently under early phases of development, for the PMS instrument onboard the LISA S/C. The mechanical enclosure has been designed following a modular approach. Each PCB will be assembled into an individual enclosure, so future upgrades in the design without affecting the entire architecture. The thermal analysis conducted so far has concluded with the feasibility of a passive thermal management system in vacuum environments, based on heat conductivity throughout the mechanical enclosure towards the instrument baseplate. In particular, the following instrument features have been included within the analysis: 1. analog signal conditioning electronics, 2. analog-to-digital conversion, and 3. FPGA core signal processing, 4. high-phase fidelity frequency synthesis and 5. frequency distribution chain, i.e., all features with the most stringent thermal requirements of the PMS-EM architecture. Although the high-power consumption demands of the instrument, the proposed thermo-mechanical design showed a suitable implementation for reliable operation of components, below maximal specified temperature ranges, allowing safe operation of the electronics over mission lifetime. As the proposed design relies only on passive conductive heat transfer methods, it is implicit a reduction of instrument complexity, avoiding complex thermal approaches based on heat pipes distributions or active control systems. Moreover, the modular approach and thermal management system enhances the integration with adjacent modules and reduce cost when assembly the instrument within the payload. In this master thesis, it has been also designed and manufactured several mechanical enclosures, together with an active thermal management system, for preliminary prototyping of analog signal acquisition electronics. These prototypes have been tested in air, setting the thermal stability requirement at the thermal reference point (TRP). Test results have verified a thermal stability requirement below 0.1 K/Hz in order to accomplish with the stringent µ-cycle phase noise performance in the mHz frequency band. Further work will test those prototypes in Vacuum conditions, consolidating thermal modelling and noise coupling as initial precursors of the PMS-EM thermally critical module developments.

  • Nisa, Yemeri
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences.
    Customer Loyalty - Does pricing matter?: A study of the managers’ perspective2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Managers have to consider different methods of keeping customers loyal to their specific company in order to secure revenue. Traditionally, pricing and pricing strategies have been good ways of acquiring and keeping customers. The purpose of this thesis is to provide a better understanding of how managers view this phenomenon today. In a sense, to analyze which importance managers place on pricing as a method of achieving customer loyalty.

    In order to obtain a greater understanding of the subject, semi-structured interviews with non-standardized questions took place. The thesis used a thematic approach to analyze the collected data. The findings and conclusions suggested that managers view price as an important factor but there are several other factors such as flexibility, customer satisfaction and competence that should be given an equal amount of attention if a company is to achieve customer loyalty.

  • Soleimanmeigouni, Iman
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Ahmadi, Alireza
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Nissen, Arne
    Trafikverket.
    Xiao, Xun
    School of Fundamental Sciences, Massey University, Palmerston North, New Zealand.
    Prediction of railway track geometry defects: a case study2019In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980Article in journal (Refereed)
    Abstract [en]

    The aim of this study has been to develop a data-driven analytical methodology for prediction of isolated track geometry defects, based on the measurement data obtained from a field study. Within the study, a defect-based model has been proposed to identify the degradation pattern of isolated longitudinal level defects. The proposed model considered the occurrence of shock events in the degradation path. Furthermore, the effectiveness of tamping intervention in rectifying the longitudinal level defects was analysed. The results show that the linear model is an appropriate choice for modelling the degradation pattern of longitudinal level defects. In addition, a section-based model has been developed using binary logistic regression to predict the probability of occurrence of isolated defects associated with track sections. The model considered the standard deviation and kurtosis of longitudinal level as explanatory variables. It has been found that the kurtosis of the longitudinal level is a statistically significant predictor of the occurrence of isolated longitudinal level defects in a given track section. The validation results show that the proposed binary logistic regression model can be used to predict the occurrence of isolated defects in a track section.

  • Salehi, Shahin
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Machine Learning for Contact Mechanics from Surface Topography2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
  • Ávila Braz, Thaís
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Shrinkage Calculation in the Continuous Casting of Duplex Stainless Steel2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • Jildesten, Jacob
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Sprängsalvor i olika bergarter2019Independent thesis Basic level (professional degree), 180 HE creditsStudent thesis
    Abstract [en]

    The master thesis was made at Bergsskolan in Filipstad in cooperation with Skanska Industrial Solutions AB. The follow-up was made during the time period of April – June 2019. The main purpose of the thesis was to create a follow-up system that Skanska could use and develop into a real working tool in the future. The focus of the system was aimed at the most important parameters of successful blasting. Skanskas blasting records from the different opencast mines were used to create the follow-up system. SGU: s rock map of Sweden was also used to locate the different rock types in the opencast mines. The system was created in the data program Excel. The system is based on rocks versus mines, were the blasting information is connected to the mines. The follow-up system works like this: 1. Choose the type of rock you are searching for  the system will then show you all the opencast mines that operate in that kind of rock. 2. Click on the mine that you are searching for  the system will take you to that mines blasting information. 3. Choose the burst number and apply all the relevant blasting information in the right boxes. 4. Save the file  done! The result showed that the goal of the thesis was reachable. A follow-up system was created were blasting information in different rocks was shown. The system is only a prototype of how a follow-up system in different rocks can look like. If the company wishes to use the system, then it should be recreated in another data program (not Excel) that specifies on database programming.

  • Lundberg, Christoffer
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    CoFramer: Ett diskussionsformat för djupa diskussioner på publika forum med låg Information Overload inspirerat av Philosophy for Children2019Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The focus of this essay is to develop a design concept for online public discussions with deep discussions and low information overload. The method used is Concept Driven Interaction Design (CDID) which involves constructing a design concept by applying a variety of theories in tangible interaction design. A design concept has three basic parts: a name, high-level goals and outlines generic principles. CDID includes seven steps which is used in this work:

    1.      Concept Generation – Formatted into a table that compare forum discussion (with several hypothesis) compared to discussions with the method Philosophy for Children (P4C) and other theories.

    2.      Concept Exploration – Eight distinct design aspects are identified from the comparison table.

    3.      Internal Concept Critique – The design aspects are compared to three similar discussion formats.

    4.      Design of Artifacts – Design concept version 1 is created.

    5.      External Design Critique – Interviews are conducted to explore their general experience of online discussions, investigate the hypothesis from the comparison table and to seek direct feedback on the first draft of the design concept.

    6.      Concept Revisited – Changes are made to the design concept based on the interview material and the direct feedback.

    7.      Concept Contextualization – The design concept is related to the original literature.

    The result of the study is a design concept named CoFramer. CoFramer’s generic principles are summarized and contrasted against factors identified from the interview material in this table:

    Tabell 2: CoFramer’s generic principles and interviews about online discussions.

    CoFramer’s generic principles | From interview material on forum discussion

    Organized start and ending | Discussions without clear ending

    Limited number of participants | Large number of participants

    Minimum number of participants | Large number of inactive spectators

    Explicit participants | Low information about participants

    Common conditions | Vagueness in participants conditions

    Limited information density per post | Long posts and/or fast posts

    The red thread and parallel threads | Often parallel threads

    Active facilitator | Unresolved misunderstandings

    The study indicates that CoFramer would create more structured discussions with a lower amount of information overload and less grounding cost compared what normally arise in public online discussions.

  • Pavuluri, Sri Harsha
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Development of an Automated Test Platform for Characterization and Performance Assessment of Electronic Modules in Electric Thrusters: The TESPEMET Project2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    There has been a sharp increase in the market for electric propulsion systems for small satellites in the recent years. Electric propulsion systems have become smaller, more efficient and cheaper, which made them ideal for small satellites because they have a low thrust requirement and benefit significantly from the high specific impulse (Isp) that is characteristic to electric thrusters. These thrusters are generally fabricated and tested manually and there is a low degree of automation in the process. As the demand for the thrusters increases, there is a need to improve the speed of the fabrication and testing process. The Test Platform for Electronics Modules in Electric Thrusters (TESPEMET) project at ThrustMe is an attempt to design a system that addresses this issue. The vision is to have a test platform that facilitates the testing of ThrustMe's Electric Thrusters by applying various source and load conditions, emulating events while performing instrumentation during the test process and generating a test report at the end of the test procedure. The development of such a test platform would enable and accelerate the test and qualification process of the thrusters significantly. This thesis presents the technical design of this test platform along with the results obtained, encountered problems and solutions. Future work and design changes have also been proposed based on the knowledge gained during the Research and Development process.

  • Public defence: 2019-12-05 16:29 E231, Luleå
    Hua, Jing
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Active friction control by using CO2 and moisture2019Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Nowadays the demand for intelligent control of tribological interactions is strongly increasing in various applications. We often strive to minimize friction but there are also many situations where high friction is desirable. In some cases, something in between, i.e. optimum friction, is attractive. Driven by the broad application prospects, many controllable friction systems regulated with external stimuli such as solvent, pH, temperature, electric potential, and magnetic field have been designed and fabricated. When external stimuli are imposed on the smart materials, the macroscopic physicochemical properties of the materials are dramatically changed, making controllable friction behavior to become possible. However, most of these exploratory works are in nano/micro size and it’s difficult to use these incredible methods in macroscale directly due to that macroscopic laws of friction do not generally apply to nanoscale contacts. This thesis attempts to find more versatile methods of friction control and try to find the possibility to achieve friction control at macro-size.

    Firstly, since viscosity plays an important role in elastohydrodynamic lubrication (EHL) at macro-size, it is instigated if it would be possible to adjust friction by controlling viscosity in a lubricated contact. By exploiting the ability to adjust the viscosity of the switchable ionic liquids, 1,8-Diazabicyclo (5.4.0) undec-7-ene (DBU)/ glycerol mixture via the addition of CO2, the friction could be controlled in the EHL regime (Paper Ⅰ). In order to understand more about the lubricating mechanism of DBU/glycerol/CO2 mixture, the central film thickness of the lubricants as a function of the entrainment speed was investigated.

    Secondly, due to that adhesion could have influence on boundary lubrication (BL) friction at macro-size, it is investigated if it would be possible to adjust friction in a lubricated contact by controlling environmental humidity, which can alter the H-bond types, leading the change of adhesion. By exploiting the ability to adjust the environmental humidity by various saturated salt solutions, friction behavior lubricated by Choline L-Proline ([Cho][Pro]) could be modulated in a wide range of relative humidities (RH) (Paper Ⅱ).

  • Abed, Salwan Ali
    et al.
    Department of Environment, College of Science, University of Al-Qadisiyah, Iraq.
    Ewaid, Salam Hussein
    Technical Institute of Shatra, Southern Technical University, Iraq.
    Al-Ansari, Nadhir
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Evaluation of Water quality in the Tigris River within Baghdad, Iraq using Multivariate Statistical Techniques2019In: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 1294, article id 072025Article in journal (Refereed)
    Abstract [en]

    This research concentrated on the Tigris River water quality monitoring information. Some multivariate statistical techniques were applied like basic Ingredient (PC) test, discriminant analysis (DA), multiple linear regression analysis (MLRA) to evaluate important parameters affecting water quality during year 2017-2018. The study included 25 water quality parameters, viz., Temperature (T), Potential of Hydrogen (pH), Turbidity (Tur), Total Alkaline (TA), Full rigidity (TH), Calcium (Ca+2), Chloride (Cl-1), Magnesium (Mg+2), Electrical Conductivity (EC), Sulfate (SO4-2), Total Solids (TS), Suspended Solids (SS), Iron (Fe+2), Fluoride (F-1), Aluminum (Al+3), Nitrite (NO2-1), Nitrate (NO3-1), Silica (SiO2), Phosphate (PO4-3), Ammonia (NH3), Dissolved Oxygen (DO), Biochemical Oxygen Demand (BOD5), Chemical Oxygen Demand (COD), Sodium (Na+1), and Total Dissolved Solids (TDS). Generally, all the parameters were within the standards except Tur, TA, Ca+2, EC, SO4-2. The levels of Tur and EC are of critical factors influence upon the Tigris water quality. The PCA identified six principal components responsible for 78.12% of the variation caused by the industrial, domestic, municipal and agricultural runoff pollution sources. DA results produced the eight parameters; T, BOD5, EC, Mg+2, DO, Tur, Na+1, and COD as the most significant parameters differentiating the two parts of the year (the cold and warm seasons). The result of MLRA showed that BOD5, Na+1, T, DO, and PO4-3 are the important dependable factors for predicting the COD value as an indicator of organic and nonorganic pollution. This research demonstrated success importance utilizing Multivariate statistical methods like valuable instrument of administration, control, and preserve the water of the river.

  • Humad, Abeer
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Habermehl-Cwirzen, Karin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Cwirzen, Andrzej
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Effects of fineness and chemical composition of blast furnace slag on properties of alkali-activated binder2019In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 12, no 20, article id 3447Article in journal (Refereed)
    Abstract [en]

    Abstract: The effects of fines and chemical composition of three types of ground granulated blast furnace slag (GGBFS) on various concrete properties were studied. Those studied were alkali activated by liquid sodium silicate (SS) and sodium carbonate (SC). Flowability, setting times, compressive strength, efflorescence, and carbonation resistance and shrinkage were tested. The chemical composition and microstructure of the solidified matrixes were studied by X-ray diffraction (XRD), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) coupled with EDX analyser. The results showed that the particle size distribution of the slags and the activator type had significantly stronger effects on all measured properties than their chemical composition. The highest compressive strength values were obtained for the finest slag, which having also the lowest MgO content. SC-activated mortar produced nearly the same compressive strength values independently of the used slag. The most intensive efflorescence and the lowest carbonation resistance developed on mortars based on slag containing 12% of MgO and the lowest fineness. The slag with the highest specific surface area and the lowest MgO content developed a homogenous microstructure, highest reaction temperature and lowest drying shrinkage. Thermogravimetric analysis indicated the presence of C-(A)-S-H, hydrotalcite HT, and carbonate like-phases in all studied mortars.

  • Danielsson, Evelina
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Vad ska glesbygdskommunerna göra med bioavfallet?: Fallstudie för Vilhelmina kommun2019Independent thesis Advanced level (professional degree), 300 HE creditsStudent thesis
    Abstract [sv]

    I denna rapport belyses vilka särskilda förutsättningar som råder i glest befolkade kommuner, och mer specifikt fjällkommuner, när det kommer till insamling av bioavfall i form av matavfall och avloppsslam. Detta görs genom en fallstudie över Vilhelmina kommun som år 2019 är en av alla de kommuner som ännu inte infört separat insamling av matavfall.

    De särskilda förutsättningar som identifierats för avfallshantering i Vilhelmina kommun, och som kan antas likna de i många andra glest befolkade fjällkommuner, är de stora avstånden, de små avfallsmängderna, det vikande befolkningsunderlaget samt att insamlingen ska fungera i hårt väder och under långa kalla vintrar med mycket snö. Även turismen och fritidshusbebyggelsen i kommunen ger upphov till utmaningar vad gäller insamlingen av bioavfall.

    I rapporten jämförs befintliga system och metoder för insamling av matavfall och avloppsslam med avseende på miljömässig hållbarhet och praktisk tillämpbarhet i en glest befolkad kommun som Vilhelmina. De system för insamling av matavfall som berörs i denna rapport är system med separata kärl, flerfackskärl, optisk sortering, underjordsbehållare, sopsug, köksavfallskvarn till VA-nät och till tank, samt en ännu ej etablerad lösning i form av torrkonservering. För insamling av slam har heltömning, deltömning och tömning med slamavvattnande fordon undersökts.

    Efter genomgång av befintliga system för insamling av matavfall konstateras att inget av de i dagsläget etablerade systemen för insamling av matavfall är direkt lämpade för en glest befolkad fjällkommun som Vilhelmina kommun. Samtliga system har fördelar men också många nackdelar, ofta relaterade till dyra investeringar och de stora avstånd som råder i glest befolkade kommuner.

    Rapporten innehåller även en undersökning av möjligheterna till mellankommunala samarbeten mellan kommunerna i Västerbottens fjäll och inland när det kommer till hantering av bioavfall. Samtliga kommuner i Västerbottens inland och fjäll konstateras ha en positiv inställning till mellankommunala samarbeten kring bioavfallshantering och möjligheterna till sådana samarbeten är goda då förutsättningar och nuvarande hantering liknar varandra i de olika kommunerna. Genom mellankommunala samarbeten kan kommunerna klara investeringar i system och metoder för insamling av bioavfall som de ensamma inte kan finansiera.

    Rapporten utgör även underlag inför framtida förändringar av nuvarande insamling i Vilhelmina kommun då den innehåller en kartläggning av avfallsflöden och avfallsmängder.

  • Backman, Ylva
    et al.
    Luleå University of Technology, Department of Arts, Communication and Education, Education, Language, and Teaching.
    Gardelli, Teodor
    Luleå University of Technology, Department of Arts, Communication and Education, Education, Language, and Teaching.
    Gardelli, Viktor
    Luleå University of Technology, Department of Arts, Communication and Education, Education, Language, and Teaching.
    Strömberg, Caroline
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Social Sciences.
    Group Argumentation Development through Philosophical Dialogues for Persons with Acquired Brain Injuries2019In: International Journal of Disability, Development and Education, ISSN 034-912XArticle in journal (Refereed)
    Abstract [en]

    The high prevalence of brain injury incidents in adolescence and adulthood demands effective models for re-learning lost cognitive abilities. Impairment in brain injury survivors’ higher-level cognitive functions is common and a negative predictor for long-term out- come. We conducted two small-scale interventions (N = 12; 33.33% female) with persons with acquired brain injuries in two municipa- lities in Sweden. Age ranged from 17 to 65 years (M = 51.17, SD = 14.53). The interventions were dialogic, inquiry-based, and inspired by the Philosophy for Children Programme, a participatory thinking skills approach with documented higher-order cognitive outcomes, such as developed argumentation skills, in other target groups. Philosophical dialogues were conducted once a week in the two groups, totalling 12 dialogues per group. Group argumentation development was measured through compared scores from struc- tured observations of filmed dialogues early and late in the inter- vention. Large positive changes in mean scores from early to late in the intervention, together with constantly high facilitator quality, suggest argumentation development in the sample due to the intervention.

  • Al Dahaan, Saad A.M.
    et al.
    Department of Geology, Faculty of Science, University of Kufa, Kufa, Iraq.
    Al-Ansari, Nadhir
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Salinity functions for groundwater at Safwan, South Iraq2019In: Journal of Environmental Hydrology, ISSN 1058-3912, E-ISSN 1996-7918, Vol. 27, no 7, p. 1-11Article in journal (Refereed)
    Abstract [en]

    Function type between electrical conductivity and total dissolved solids is polynomial and the exponential which are taken according to the water quality classification for irrigation. These functions relate the EC in ds/m to the salinity in term of part per million or to the half salinity in equivalent per million directly or in form of logarithmic transformation. A statistical test for best fit is considered for the selection of the type of a representative function. The irrigation salinity classification is taken as index of grouping extended to moderately sensitive vegetable crop tomato as salinity tolerance rating up to 15 ds/m groundwater salinity used for irrigation at Safwan area of arid climate. All fitted type of functions is programmed within a flow model computer of basic language by which the output from of both methods is an average final value. Thus the coast of analysis is reduced. This type of functions is standard for groundwater and so designed to involve the water type. The involved parameter for Safwan area is 0.5 for more than 5 ds/m in case of ppm half total and it is 1.3 for less than 5ds/m salinity, or using the direct model.

  • Kheffache, Mansour
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Energy-Efficient Detection of Atrial Fibrillation in the Context of Resource-Restrained Devices2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    eHealth is a recently emerging practice at the intersection between the ICT and healthcare fields where computing and communication technology is used to improve the traditional healthcare processes or create new opportunities to provide better health services, and eHealth can be considered under the umbrella of the Internet of Things. A common practice in eHealth is the use of machine learning for a computer-aided diagnosis, where an algorithm would be fed some biomedical signal to provide a diagnosis, in the same way a trained radiologist would do.

    This work considers the task of Atrial Fibrillation detection and proposes a novel range of algorithms to achieve energy-efficiency. Based on our working hypothesis, that computationally simple operations and low-precision data types are key for energy-efficiency, we evaluate various algorithms in the context of resource-restrained health-monitoring wearable devices. Finally, we assess the sustainability dimension of the proposed solution.

  • Lempinen, Simja
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Grundvattenkarakterisering med syreisotoper: En fältstudie i Gäddviks vattentäkt i Luleå2019Independent thesis Advanced level (professional degree), 300 HE creditsStudent thesis
    Abstract [en]

    Groundwater and artificially recharged groundwater are important sources offreshwater in Sweden. In growing societies an ever larger demand is put onmunicipalities drinking water production facilities. Especially in coastal areas oraquifers that are located below the highest coastal line, there can be ionically strongpaleowaters at greater depths which then risk being pumped up to the municipal watersupply. A common problem for municipal water works is that production wells pumpup ionically strong water, with a high electrical conductivity when the production wellsare stressed at high effect or longer periods of constant pumping. At the waterworks ofGäddvik in Luleå municipality certain wells have shown tendencies of higher electricalconductivities in the produced water, while some wells seem to never produce waterwith higher electrical conductivity, no matter how much they are pumped. Highelectrical conductivities has earlier been assumed to be paleowaters from below theaquifer with great concentrations of chloride, but this is not certain.This work investigates the possibilities of characterizing groundwater by using theoxygen isotopes 16O & 18O as well as main element analysis. In the work a field surveywas performed where groundwater was pumped up from 26 observational wells and 5productional wells at Gäddviks aquifer in Luleå. The samples were analyzed for isotopesof both oxygen and hydrogen as well as the main elements. The results have shown thatit is possible to correlate the heaviest isotopic signatures of oxygen with the highestmeasured values of chloride. This indicates that there is a potential value for identifyingpaleowaters with the help of oxygen isotopes especially when correlated to mainelement data.

  • Garmabaki, Amir Soleimani
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Thaduri, Adithya
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Kumar, Uday
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Laue, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Marklund, Stefan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Odelius, Johan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Bansal, Tarun
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Rantatalo, Matti
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Asplund, Matthias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Indahl, Stefan
    A Survey on Underground Pipelines and Railway Infrastructure at Cross-Sections2019In: ESREL-2019 / [ed] Michael beer, Enrico Zio, 2019Conference paper (Refereed)
    Abstract [en]

    Underground pipelines are an essential part of the transportation infrastructure. The structural deterioration of pipelines crossing railways and their subsequent failures are critical for society and industry resulting in direct and indirect costs for all the related stakeholders. Pipeline failures are complex processes, which are affected by many factors, both static (e.g., pipe material, size, age, and soil type) and dynamic (e.g., traffic load, pressure zone changes, and environmental impacts). These failures have serious impacts on public due to safety, disruption of traffic, inconvenience to society, environmental impacts and shortage of resources. Therefore, continuous and accurate condition assessment is critical for the effective management and maintenance of pipeline networks within transportation infrastructure. The aim of this study is to identify failure modes and consequences related to the crossing of pipelines in railway corridors. Expert opinion have been collected through two set of questionnaires which have been distributed to the 291 municipalities in the whole Sweden. The failure analysis revealed that pipe deformation has higher impact followed by pipe rupture at cross-section with railway infrastructure. For underground pipeline under railway infrastructure, aging and external load gets higher ranks among different potential failure causes to the pipeline.

  • Garmabaki, Amir Soleimani
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Marklund, Stefan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Thaduri, Adithya
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Kumar, Uday
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Underground pipelines and railway infrastructure: failure consequences and restrictions2019In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980Article in journal (Refereed)
    Abstract [en]

    Underground pipelines are an essential part of the transportation infrastructure. The structural deterioration of pipelines crossing railways and their subsequent failures can entail critical consequences for society and industry, resulting in direct and indirect costs for all the stakeholders involved. Therefore, continuous and accurate condition assessment is critical for the effective management and maintenance of pipeline networks within the transportation infrastructure. The aim of this study has been to identify failure modes and consequences related to pipelines crossing railway corridors. Expert opinions have been collected through interviews and two sets of questionnaires have been distributed to the 291 municipalities in Sweden, with 137 responses in total. The failure analysis has revealed that pipe deformation has the highest impact, followed by pipe rupture at locations where pipelines cross railway infrastructure. For underground pipelines under railway infrastructure, ageing and the external load were awarded a higher ranking than other potential causes of pipeline failure.

    Authors gratefully acknowledge the funding provided by Sweden’sinnovation agency, Vinnova, through the strategic innovation programmeInfraSweden2030. The funding was granted in a competitiveapplication process that assessed replies to an open call for proposalsconcerning “Condition Assessment and Maintenance of TransportInfrastructure (Grant No. 2016-033113)”.

    Authors gratefully acknowledge the technical support and collaboration(In-kind support) of Arrsleff R€orteknik at Sweden, Luleå RailwayResearch Center (JVTC), Stormwater&Sewers and the SwedishTransport Administration (Trafikverket). In addition, the authors arethankful to the anonymous referees for their constructive commentsand Dr Matthias Asplund and Dr Masoud Naseri for their support andsuggestions.

  • Videll, Ebba
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering. Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Survey of sulphates in process water of LKAB - Kiruna operation2019Independent thesis Advanced level (professional degree), 300 HE creditsStudent thesis
    Abstract [en]

    Sulphate-rich wastewater is an increasing concern for industries as LKAB. The water chemistry of the LKAB Kiruna water system is characterized by high alkalinity, high pH (pH 7.5-9.0) and high concentrations of chemical species and soluble minerals. The sulphate content in the water system of Kiruna is associated with the dissolution of calcium sulphate as anhydrite (CaSO4) and gypsum (CaSO4 2H2O). However, the high concentrations of sulphate in the effluents from the LKAB Kiruna operation are unique for iron ore mining. 

     

    The aim of the thesis was to study and evaluate the behavior of sulphate in the process water system of the Kiruna concentrator plants. This was done by laboratory grinding (leaching tests), equilibrium calculations with the HSC software and mass balancing of the concentrator KA3 in Kiruna. The highest concentrations of sulphate have been detected in the process water of KA3, hence the focus has been on KA3 regarding sampling, evaluation and comparison. Water treatment technologies for sulphate and the effect of process water on ore processing have not been included in this project.

     

    The laboratory grinding was done using process water and ore from the concentrator KA3. During the experimental work with laboratory grinding the parameters pH, temperature and operating times for primary- and secondary grinding, respectively, were varied. The observations from the experimental work were further confirmed by equilibrium calculations and mass balancing. The following conclusions were drawn.  

     

    • Anhydrite/gypsum is not leached from the ore during ore processing with process water having concentrations of sulphate already close to the saturation point at approximately 1800 mg/L. If the process water is diluted with water with lower sulphate content, e.g. mine water or a diluted return water from the pond system (e.g. during spring flood), anhydrite/gypsum in ore will be dissolved until the sulphate concentration reaches the saturation point.

    • The ionic strength of the process water controls the saturation point and thus the sulphate concentration.

    • Leaching of anhydrite/gypsum in saturated process water, with respect to sulphate, is not affected by grinding time or adjusted conditions in the process water, such as temperature or pH value. 

     

    For further work, it is recommended to investigate the behavior of sulphate in the tailings pond system to increase knowledge of the overall behavior in the water system. In addition, a similar investigation of the behavior of uranium in the process water is recommended in order to face future environmental standards.

  • Kronsell, Ida
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Structural control on the Peña del Seo tungsten-greisen vein deposit, northwest Spain2019Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    Tungsten is listed on the European Commission list of critical raw materials that are crucial to Europe’s economy. By raising awareness of tungsten as a critical raw material the EU can prioritise to enhance exploration, mining and recycling of tungsten. In this thesis the structural relationship between wall rock and veins, in a greisen-tungsten vein deposit, were analysed with the intention to interpret how tectonic deformation events control the emplacement of tungsten-bearing veins. The objective of this thesis is to investigate if and how structures controlled hydrothermal fluid flow and ore formation in the Peña del Seo tungsten-greisen vein deposit.

    Greisen systems are associated with tin and tungsten-bearing minerals and are related to intrusive magmatic bodies of granitic composition. Greisen-related granites (leucogranites), form at shallow depths in the crust (1.5-4 km) generally in intracontinental tectonic settings such as orogenic belts.

    The study site is located in the West Asturian-Leonese Zone in northwest Spain. This zone marks the transition between the foreland and the hinterland and is recognized as being part of a continental margin, where Palaeozoic rocks were deposited unconformably. These rocks were subsequently subjected to folding during the Variscan orogeny (370-290 Ma). Three main types of structures were generated due to three deformational phases (D1, D2 and D3) during the Variscan orogeny. D1 resulted in east-verging recumbent folding and formation of a related axial-planar parallel cleavage (S1), D2 resulted in displacement along large thrust sheets and D3 produced upright folding and refolding of F1 folds.

    Geological mapping with a focus on structural geology was carried out in March 2019, covering an area of approximately 0.25 km2. Structural measurements and oriented rock samples for microstructural study in thin sections were collected in the field. Additionally, photogrammetric mapping of structures was performed on a 3D photogrammetry model derived from a UAS survey.

    The geometry of the Peña del Seo tungsten-greisen vein deposit is interpreted to result from two major deformation events. The axial planar foliation (S1) at Peña del Seo is correlated to the regional fabric that developed during D1 of the Variscan orogeny. The related F1 folds are caused by buckling accompanied by flexural slip folding mechanism during D1. Forceful intrusion of the granite underlying the Peña del Seo deposit caused bending of the overlying rocks layers during D2. Layer-parallel stretching is likely to have caused tension fractures perpendicular to bedding in the outer arc of the F2 fold hinge. The formation of local crenulation and related spaced cleavage can be explained by layer-parallel shortening in the inner arc of the F2-fold. Local transposition of S1-foliation occurred during emplacement of quartz veins and explains the different orientation of strike of foliation between the northern and southern parts of the area. Fractures forming during formation of F2-fold are likely to have worked as conduits for ascending hydrothermal, ore-bearing fluids forming the Peña del Seo tungsten-greisen vein deposit.

  • Saeedi, Kubra
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Machine Learning for Ddos Detection in Packet Core Network for IoT2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • Adlén, Cecilia
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences.
    The Production Mirror: How an interactive interface can boost motivation for industrial workers2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This master thesis concerns industrial workers’motivation and if it can be influenced by informationdissemination through an interactive interface. Focus hasbeen to research human motivators in theory to seehow these can be applied in an industrial environmentwith the hope of giving the workers a deeperknowledge of the company’s product and / or processand thus increasing her motivation. The project is basedon the assumption that an increased understanding intomore than what is limited by the worker’s tasks canhave a positive effect and strengthen his or her sense oftheir role in a wider context.The master thesis shows how a design process can beapplied to an organizational problem in industries,where the different phases of the process includeconcerned people repetitively to seek knowledge, ideasand solutions together with those who may be affectedby the results of the work.In industries today, the workload is usually distributedacross departments where staff are divided into teams.There is some circulation within the department but lesscommonly across departmental boundaries. This canlimit the worker’s perception of the entire process andresult in a detailed understanding of only a limited partof the process.Industry 4.0 is expected to be the solution for retrievingand retaining companies in Europe by building smartfactories with technology that allows the machines tocommunicate. Industry 4.0 is also expected to reduce thenumber who have work in industries, human interactionsand responsibilities. Which may have the negative effect offurther reinforcing one of today’s problems, the workerbeing further isolated from the process. Which are factorsthat, in theory, contribute to a reduced level of motivationand will therefore have a negative impact on their workaspirations.The work has been carried out with RISE Interactive inPiteå as client. RISE is part of our Swedish researchinstitute and works with user-centered technologicaldevelopment in many different industries.The degree project resulted in a large amount of ideas forhow work in industries could benefit from an interactiveinterface for disseminating information and knowledge.The final solution is presented in a stop motion movieshowing the solution that was chosen by industrialworkers. The solution shows how coloured lamps can beused to visualize progress-related information during thecourse of the work at the same time as it enables easycommunication between employees.

  • Public defence: 2019-12-06 09:00 E632, Lulea
    Gantasala, Sudhakar
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Detection of blade icing and its influence on wind turbine vibrations2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Wind turbine installations in extreme conditions like cold climate have increased over thelast few years and expected to grow in future in North America, Europe, and Asia regions due to good wind resources and land availability. Their installed capacity could reach 186 GW by the end of 2020. The cold climate sites impose the risk of ice accumulation on turbines during the winter due to the humidity at low temperatures. Since the atmospheric and operating conditions of the wind turbine leading to blade icing vary stochastically in space and time, the resulting ice accumulation is completely random, it is even different for turbines within the same site. Ice accumulation alters aerofoil shapes of the blade, affecting their aeroelastic behavior. The icing severity at different locations of the blade and their non-uniform distribution on blades have a distinct influence on turbine power output and vibrations. The current thesis proposes a methodology to investigate such behavior of wind turbines by considering the structural and aerodynamic property changes in the blade due to icing. An automated procedure is used to scale simulated/measured ice shape on aerofoil sections of the blade according to a specified ice mass distribution. The aeroelastic behavior of the blades is simulated considering the static aerodynamic coefficients of the iced aerofoil sections. The proposed methodology is demonstrated on the National Renewable Energy Laboratory (NREL) 5 MW baseline wind turbine model. The method can be leveraged to analyze the influence of icing on any wind turbine model. De/Anti-icing systems are installed on the turbines to mitigate the risks associated with icing. It is essential to detect icing at the early stage and initiate these systems to avoid production losses and limit the risks associated with ice throw. Ice accumulation increases blade mass and its spatial distribution changes natural frequencies of the blade. A detection technique is proposed in this thesis to characterize ice mass distribution on the blades based on its natural frequencies. The detection technique is validated using experiments on a small-scale cantilever beam and 1-kW wind turbine blade set-ups and its effectiveness is also verified on large-scale wind turbine blades using numerical models. The proposed technique has the potential for detecting ice masses on large wind turbines operating in cold climate as it requires only first few natural frequencies of the blade. These natural frequencies are usually excited by the turbulent wind in operation/standstill conditions and they can be estimated from the vibration measurements of the blade.

  • Han, Lei
    et al.
    Sandberg, Dick
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Reducing the set-recovery of surface-densified Scots Pine by furfuryl alcohol modification2019In: Proceedings of the 62nd International Convention of Society of Wood Science and Technology, Tenaya Lodge, Yosemite, California, USA, October 20-25: Convention Theme: Renewable Materials and the Wood-based Bioeconomy / [ed] LeVan-Green, S., SWST, Society of Wood Science and Technology , 2019, p. 200-Conference paper (Refereed)
  • Myronycheva, Olena
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Karlsson, Olov
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Sehlstedt-Persson, Margot
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Öhman, Micael
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Sandberg, Dick
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Portable microNIR sensor for the evaluation of mould contamination on wooden surfaces2019In: Proceedings of the 62nd International Convention of ociety of Wood Science and Technology. Convention  Tenaya Lodge, Yosemite, California, USA, October 20-25: Theme: Renewable Materials and the Wood-based Bioeconomy, / [ed] LeVan-Green, S., SWST, Society of Wood Science and Technology , 2019, p. 46-51Conference paper (Refereed)
  • Segerstedt, Anders
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Business Administration and Industrial Engineering.
    Täcktidsplanering och ”Cover-Time Planning”: om vad som finns att läsa på nätet2019Manuscript (preprint) (Other academic)
  • Burman, Anton
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    INHERENT DAMPING IN A PARTIALLY DRY RIVER2019In: Proceedings of the 38th IAHR World Congress / [ed] Lucas Calvo, 2019, p. 5091-5100Conference paper (Refereed)
    Abstract [en]

    As intermittent power sources such as solar power and wind power gains traction in Scandinavia it is likelythat the electricity production will become increasingly dependent on hydro power as a buffer in times ofpower deficit from intermittent power sources due to weather conditions. Rapid changes in hydro powerdemand can rapidly change the flow conditions in proximity to the power plant. This paper aims to model thetransient behavior and quantify the inherent damping in a dry reach in proximity to the largest hydro powerplant in Sweden, with respect to production. A two-dimensional model solving the Navier-Stokes equationswith shallow water approximations was set up using the open-source solver Delft3D. The Manning numbers inthe reach was calibrated with measured steady state water surface elevation data. The simulation data wasthen validated with transient water level measurements. The results show that it's possible to calibrate theManning numbers using steady state water level measurements. The model also shows that it's possible tocapture the inherent damping and more transient behavior using Delft3D. The results can be used to bettermodel rivers without the need for resolving the upstream reach. The results can also be used forecohydraulical applications where the transient behavior is important

  • Törlind, Peter
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Humans and technology.
    Implementation of integrated learning experiences and active learning in a creative concept development course2019In: 7:e Utvecklingskonferensen för Sveriges ingenjörsutbildningar, Luleå, 2019Conference paper (Refereed)
    Abstract [en]

    A designer needs to possess capabilities and knowledge outside the traditional engineering domains – these capabilities and experiences are difficult to obtain in a traditional classroom setting; therefore, the integrated learning experiences can provide the experience and training of these capabilities. A crucial part of design education is to teach students the ability to cope with uncertainty and ambiguity – traits of a successful designer.

    The paper presents the design of a course in creative concept development that implements several educational ideas from active learning, which is an improvement over traditional learning. Active learning focuses on engaging students in and outside the classroom, an essential part of active learning includes mixing between theory and practical exercises and here it is crucial that the physical environment quickly adapts to different types of learning activities.

    The paper shows three concrete examples of how to integrate active learning – learning outside the classroom, guided design and role-play and games. The course has reflection and feedback throughout, both as an integral part of the lectures and assessment. To complement active learning, we must have effective evaluation processes to measure them. Different categories of learning outcomes require different assessment methods.

    Through continuous improvement, much based on the students' feedback and reflections, the course is very popular with students.  Students appreciate the mix of exercises, unconventional presentations, challenges and games. Students also appreciate the breadth of assessment that s assess an in-depth understanding.

  • Wikberg-Nilsson, Åsa
    et al.
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Humans and technology.
    Törlind, Peter
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Humans and technology.
    Implementation of workbooks as an active learning tool for Industrial Design Engineering2019In: 7:e Utvecklingskonferensen för Sveriges ingenjörsutbildningar, Luleå, 2019Conference paper (Refereed)
    Abstract [en]

    This paper focuses on the workbook approach. It is a tool for active and self-regulated learning, allowing for teachers to guide students in a certain direction and to provide clear goals in otherwise rather open-ended design projects.  The learning strategies self-regulated students employ support setting up goals and evaluate their performance, this strategy is guided by the workbook approach. Hence, it supports also previously non-self-regulated learners in devoting to the projects in more informed ways.  Industrial design engineering is unique compared to other engineering educations as it combines both artistic and scientific approaches and practices, it combines technical rationality and reflective practice. Typical design projects address the social, economical, cultural, material and technical dimensions of a situation in iterative design thinking cycles of gaining empathy for user needs, visualizing and materializing ideas and concepts and testing with users to inform the process. The workbook approach is a tool to guide such open-ended projects through cycles of reflection in- and on- actions. This informs learning and understanding during the process, rather than afterwards when final results is done. The workbook approach is currently implemented in five compulsory and several elective courses at Industrial Design Engineering (IDE) at Luleå University of Technology (LTU). The results so far are indications of better self-regulation in subsequent courses and students’ understandings of the end-result not being the project result, but for them to be the next generation of independent design engineers. As of yet, this is a work-in-progress and more studies are needed to provide evidence of concept such as more active and/or self-regulated learners. The workbook approach however seems to contribute in students being more independent as it guides them through the project process. In conclusion, based on our preliminary findings, we consider that the workbook approach shows indications of being a tool to support active and self-regulated learning in open-ended design projects.

  • Seo, Jungryul
    et al.
    Department of Computer Engineering, Ajou University, Suwon, Korea.
    Laine, Teemu H.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Sohn, Kyung-Ah
    Department of Computer Engineering, Ajou University, Suwon, Korea.
    An Exploration of Machine Learning Methods for Robust Boredom Classification Using EEG and GSR Data2019In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 19, no 20, article id 4561Article in journal (Refereed)
    Abstract [en]

    In recent years, affective computing has been actively researched to provide a higher level of emotion-awareness. Numerous studies have been conducted to detect the user’s emotions from physiological data. Among a myriad of target emotions, boredom, in particular, has been suggested to cause not only medical issues but also challenges in various facets of daily life. However, to the best of our knowledge, no previous studies have used electroencephalography (EEG) and galvanic skin response (GSR) together for boredom classification, although these data have potential features for emotion classification. To investigate the combined effect of these features on boredom classification, we collected EEG and GSR data from 28 participants using off-the-shelf sensors. During data acquisition, we used a set of stimuli comprising a video clip designed to elicit boredom and two other video clips of entertaining content. The collected samples were labeled based on the participants’ questionnaire-based testimonies on experienced boredom levels. Using the collected data, we initially trained 30 models with 19 machine learning algorithms and selected the top three candidate classifiers. After tuning the hyperparameters, we validated the final models through 1000 iterations of 10-fold cross validation to increase the robustness of the test results. Our results indicated that a Multilayer Perceptron model performed the best with a mean accuracy of 79.98% (AUC: 0.781). It also revealed the correlation between boredom and the combined features of EEG and GSR. These results can be useful for building accurate affective computing systems and understanding the physiological properties of boredom.