Change search
Refine search result
21222324252627 1151 - 1200 of 62955
CiteExportLink 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
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1151. Albertsson, Kim
    Towards self-learning sensors: Matching pursuit with dictionary learning on FPGA2013Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A general approach for sparse signal decomposition is matching pursuit with an over-complete dictionary of features. It has been demonstrated that this gives efficient codes when applied to images and acoustic signals. This thesis implements an on-line version of matching pursuit with Hebbian dictionary learning, which is theoretically able to process vibration and acoustic emission signals for condition monitoring of, for example, bearings. The implementation is done in C and critical parts are identified and implemented in VHDL with the goal of synthesising those parts on an FPGA. The C implementation can handle data in two formats, both fixed and floating point and is verified to be functioning in both cases. The VHDL components are verified in simulation. The maximum processing speed possible for the designed system is expected be on the order of one million samples per second, 1 Msps.

  • 1152.
    Albertsson, Kim
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Gleyzer, Sergei
    University of Florida.
    Zapata, Omar
    OProject and University of Antioquia.
    Machine Learning in High Energy Physics Community White Paper2018In: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 1085, article id 022008Article in journal (Refereed)
    Abstract [en]

    Machine learning is an important applied research area in particle physics, beginning with applications to high-level physics analysis in the 1990s and 2000s, followed by an explosion of applications in particle and event identification and reconstruction in the 2010s. In this document we discuss promising future research and development areas in machine learning in particle physics with a roadmap for their implementation, software and hardware resource requirements, collaborative initiatives with the data science community, academia and industry, and training the particle physics community in data science. The main objective of the document is to connect and motivate these areas of research and development with the physics drivers of the High-Luminosity Large Hadron Collider and future neutrino experiments and identify the resource needs for their implementation. Additionally we identify areas where collaboration with external communities will be of great benefit.

  • 1153. Albertsson, Lena
    et al.
    Brännström, Beatrice
    Marknadsorienterade informationssystem: faktorer som påverkar användningen av en kundkiosk2005Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 1154.
    Albertsson, Sophie
    et al.
    Luleå University of Technology, Department of Health Sciences, Health and Rehabilitation.
    Hjerpe, Caroline
    Luleå University of Technology, Department of Health Sciences, Health and Rehabilitation.
    Den gravida kroppen - individens eller sjukvårdens ansvar?: En kvalitativ studie om kvinnors uppfattningar och erfarenheter.2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Bakgrund: Träning under en graviditet är viktigt både ur ett fysiologiskt samt psykologiskt perspektiv. Bristande fysisk aktivitet är en stor riskfaktor för hälsan. Livshändelser såsom graviditet och förlossning kan utgöra en större risk för bristande fysisk aktivitet hos kvinnor. Gravida kvinnor rekommenderas att vara fysiskt aktiva minst 30 minuter per dag. Informationen kring fysisk aktivitet och träning är ofta bristfällig inom mödrahälsovården varför det efterlyses ett närmare samarbete mellan till exempel barnmorskor och fysioterapeuter. Genom att förbättra kvantiteten och kvaliteten på informationen angående fysisk aktivitet hos gravida finns det en möjlighet att korrigera felaktiga uppfattningar och på så sätt främja en god hälsa. Syfte: Syftet var att beskriva kvinnors egen uppfattning om fysisk aktivitet och träning under och efter en graviditet samt upplevelse av mottagen information från sjukvården angående ämnet. Metod: En kvalitativ intervjustudie genomfördes med fem kvinnor, vilka rekryterades via ett strategiskt urval. Därefter genomfördes en innehållsanalys av intervjuerna. Resultat: Analysen av intervjutexterna resulterade i en huvudkategori “Den gravida kroppen - individens eller sjukvårdens ansvar?”. Huvudkategorin innehöll följande kategorier “Kunskapsinhämtning - individens ansvar” samt “Aktivitetsnivå - individens val” med tillhörande underkategorier. Konklusion: Studien visade positiva upplevelser och uppfattningar av fysisk aktivitet och träning i samband med graviditeten. De intervjuade kvinnorna upplevde bristande information från sjukvården gällande detta ämne. De råd som kvinnorna hade fått från sjukvården upplevdes som osäkra och väldigt generella, därför fanns en önskan om att individanpassa råden.

  • 1155.
    Albeverio, S.
    et al.
    Institute of Mathematics, Ruhr-Universität, D-44780 Bochum.
    Dabrowski, L.
    SISSA.
    Kurasov, Pavel
    Luleå tekniska universitet.
    Symmetries of Schrödinger operator with point interactions1998In: Letters in Mathematical Physics, ISSN 0377-9017, E-ISSN 1573-0530, Vol. 45, no 1, p. 33-47Article in journal (Refereed)
    Abstract [en]

    The transformations of all the Schrödinger operators with point interactions in dimension one under space reflection P, time reversal T and (Weyl) scaling Wλ are presented. In particular, those operators which are invariant (possibly up to a scale) are selected. Some recent papers on related topics are commented upon

  • 1156.
    Albeverio, S.
    et al.
    Institut für Angewandte Mathematik, Universität Bonn.
    Fei, S-M
    Institut für Angewandte Mathematik, Universität Bonn.
    Kurasov, Pavel
    Luleå tekniska universitet.
    Many body problems with "spin"-related contact interactions2001In: Reports on mathematical physics, ISSN 0034-4877, E-ISSN 1879-0674, Vol. 47, no 2, p. 157-166Article in journal (Refereed)
    Abstract [en]

    We study quantum mechanical systems with "spin"-related contact interactions in one dimension. The boundary conditions describing the contact interactions are dependent on the spin states of the particles. In particular we investigate the integrability of N-body systems with δ-interactions and point spin couplings. Bethe ansatz solutions, bound states and scattering matrices are explicitly given. The cases of generalized separated boundary condition and some Hamiltonian operators corresponding to special spin related boundary conditions are also discussed.

  • 1157.
    Albeverio, S.
    et al.
    BiBoS Research Center.
    Haake, F.
    Fachbereich Physik, Universität-GH Essen.
    Kurasov, Pavel
    Luleå tekniska universitet.
    Kus, M.
    Fachbereich Physik, Universität-GH Essen.
    Šeba, P.
    Nuclear Physics Institute, Czech Academy of Sciences.
    S-matrix, resonances, and wave functions for transport through billiards with leads1996In: Journal of Mathematical Physics, ISSN 0022-2488, E-ISSN 1089-7658, Vol. 37, no 10, p. 4888-4903Article in journal (Refereed)
    Abstract [en]

    For a simple model describing the S-matrices of open resonators the statistical properties of the resonances are investigated, as well as the wave functions inside the resonator

  • 1158.
    Albeverio, S.
    et al.
    Department of Mathematics, Ruhr-University, Bochum.
    Kurasov, Pavel
    Luleå tekniska universitet.
    Finite rank perturbations and distribution theory1999In: Proceedings of the American Mathematical Society, ISSN 0002-9939, E-ISSN 1088-6826, Vol. 127, no 4, p. 1151-1161Article in journal (Refereed)
  • 1159.
    Albeverio, S.
    et al.
    Department of Mathematics, Ruhr-University, Bochum.
    Kurasov, Pavel
    Luleå tekniska universitet.
    Rank one perturbations of not semibounded operators1997In: Integral equations and operator theory, ISSN 0378-620X, E-ISSN 1420-8989, Vol. 27, no 4, p. 379-400Article in journal (Refereed)
    Abstract [en]

    Rank one perturbations of selfadjoint operators which are not necessarily semibounded are studied in the present paper. It is proven that such perturbations are uniquely defined, if they are bounded in the sense of forms. We also show that form unbounded rank one perturbations can be uniquely defined if the original operator and the perturbation are homogeneous with respect to a certain one parameter semigroup. The perturbed operator is defined using the extension theory for symmetric operators. The resolvent of the perturbed operator is calculated using Krein's formula. It is proven that every rank one perturbation can be approximated in the operator norm. We prove that some form unbounded perturbations can be approximated in the strong resolvent sense without renormalization of the coupling constant only if the original operator is not semibounded. The present approach is applied to study first derivative and Dirac operators with point interaction, in one dimension

  • 1160. Albeverio, Sergio
    et al.
    Hilbert, Astrid
    Luleå tekniska universitet.
    Kolokoltsov, Vassily
    Sur le comportement asymptotique du noyau associé à une diffusion dégénérée2000In: Comptes Rendus Mathematiques de l'Academie des Sciences = Mathematical reports of the academy of science, ISSN 0706-1994, Vol. 22, no 4, p. 151-159Article in journal (Refereed)
  • 1161. Albiin, Helena
    et al.
    Levander, Stina
    Upplevelser hos personer som lever med dialysbehandling: en litteraturstudie2006Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
  • 1162. Albing, Daniel
    Klassiska och sannolikhetsbaserade metoder för släntstabilitetsanalys2004Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 1163. Albing, Fredrik
    Trimning i FEM-simuleringar2000Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 1164.
    Albing, Malin
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mathematical Science.
    Contributions to process capability indices and plots2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis presents contributions within the field of process capability analysis. Process capability analysis deals with how to assess the capability of processes. Based on process capability analysis one can determine how the process performs relative to its product requirements or specifications. An important part within process capability analysis is the use of process capability indices. This thesis focuses on process capability indices and process capability plots. The thesis consists of six papers and a summary. The summary gives a background to the research area, a short overview of the six papers, and some suggestions for future research. The thesis summary also consists of some new results, not presented in any of the appended papers. In paper I, the frequency and use of process capability analysis, together with statistical process control and design of experiments, within Swedish companies hiring alumni students are investigated. We also investigate what motivates organisations to implement or not implement these statistical methods, and what is needed to increase the use. In papers II-III we generalize the ideas with process capability plots and propose two graphical methods, for deeming a process capable at a given significance level, when the studied quality characteristic is assumed to be normally distributed. In paper II we derive estimated process capability plots for the case when the specification interval is one-sided. In paper III we derive elliptical safety region plots for the process capability index Cpk and its one-sided correspondences. The proposed graphical methods are helpful to determine if it is the variability, the deviation from target, or both that need to be reduced to improve the capability. In papers IV-VI we propose a new class of process capability indices designed for the situation with an upper specification limit, a target value zero, and where the studied quality characteristic has a skewed, zero- bound distribution with a long tail towards large values. The proposed class of indices is simple and possesses properties desirable for process capability indices. The results in papers IV-VI are also valid for the situation with a target value, not equal to zero but equal to a natural lower limit of the quality characteristic. Three estimators of the proposed class of indices are studied and the asymptotic distributions of these estimators are derived. We also consider decision procedures, based on the estimated indices, suitable for deeming the process capability at a given significance level. The new results in the summary combines the ideas from paper II with the results in papers IV-VI and a graphical method for the class of indices proposed in IV-VI are derived.

  • 1165.
    Albing, Malin
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mathematical Science.
    Process capability analysis with focus on indices for one-sided specification limits2006Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    In this thesis some aspects of process capability analysis are considered. Process capability analysis deals with how to assess the capability of manufacturing processes. Based on the process capability analysis one can determine how the process performs relative to its product requirements or specifications. An important part within process capability analysis is the use of process capability indices. This thesis focuses on process capability indices in the situation when the specification limits are one- sided. The thesis consists of a summary and three papers, of which one is already published in an international journal. The summary gives a background to the research area, a short overview of the three papers, and some suggestions for future research. In Paper I, the frequency and use of process capability analysis together with statistical process control and design of experiments, within Swedish companies hiring alumni students are investigated. We also investigate what motivates organisations to implement or not implement these statistical methods, if there are differences in use that can be related to organisational types and what will be needed to increase the use. One conclusion drawn from the results is that the students employed in the Swedish industrial sector witness a modest use of these statistical methods and use in other sectors hiring the alumni is uncommon. In Paper II we present a graphical method useful when doing capability analysis having one-sided specification limits. This is an extension of the process capability plots previously developed for two-sided specification intervals. Under the assumption of normality we suggest estimated process capability plots to be used to assess process capability at a given significance level. The presented graphical approach is helpful to determine if it is the variability, the deviation from target, or both that need to be reduced to improve the capability. In Paper III the situation with non-negative process data having a skew distribution with a long tail towards large values are considered, when an upper specification limit only exists and the target value is 0. No proper indices exist for this specific situation, which is common in practice. We contribute to this area by proposing a new class of indices designed for skew, zero-bound distributions when an upper specification only exists and the target value is 0. This new class of indices is simple and possesses properties desirable for process capability indices. Two estimators of the proposed index are studied and the asymptotic distributions of these estimators are derived. Furthermore, we consider decision procedures, based on the estimated indices, suitable for deeming the process capability or not.

  • 1166.
    Albing, Malin
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mathematical Science.
    Process capability indices for Weibull distributions and upper specification limits2008Report (Other academic)
  • 1167.
    Albing, Malin
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mathematical Science.
    Process capability indices for Weibull distributions and upper specification limits2009In: Quality and Reliability Engineering International, ISSN 0748-8017, E-ISSN 1099-1638, Vol. 25, no 3, p. 317-334Article in journal (Refereed)
    Abstract [en]

    We consider a previously proposed class of capability indices that are useful when the quality characteristic of interest has a skewed, zero-bound distribution with a long tail towards large values and there is an upper specification with a pre-specified target value, T = 0. We investigate this class of process capability indices when the underlying distribution is a Weibull distribution and focus on the situation when the Weibull distribution is highly skewed. We propose an estimator of the index in the studied class, based on the maximum likelihood estimators of the parameters in the Weibull distribution, and derive the asymptotic distribution for this estimator. Furthermore, we suggest a decision rule based on the estimated index and its asymptotic distribution, and presents a power comparison between the proposed estimator and a previously studied estimator. A simulation study is also performed to investigate the true significance level when the sample size is small or moderate. An example from a Swedish industry is presented.

  • 1168. Albing, Malin
    et al.
    Vännman, Kerstin
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mathematical Science.
    Elliptical safety region plots for Cpk2011In: Journal of Applied Statistics, ISSN 0266-4763, E-ISSN 1360-0532, Vol. 38, no 6, p. 1169-1187Article in journal (Refereed)
    Abstract [en]

    The process capability index Cpk is widely used when measuring the capability of a manufacturing process. A process is defined to be capable if the capability index exceeds a stated threshold value, e.g. Cpk4/3. This inequality can be expressed graphically using a process capability plot, which is a plot in the plane defined by the process mean and the process standard deviation, showing the region for a capable process. In the process capability plot, a safety region can be plotted to obtain a simple graphical decision rule to assess process capability at a given significance level. We consider safety regions to be used for the index Cpk. Under the assumption of normality, we derive elliptical safety regions so that, using a random sample, conclusions about the process capability can be drawn at a given significance level. This simple graphical tool is helpful when trying to understand whether it is the variability, the deviation from target, or both that need to be reduced to improve the capability. Furthermore, using safety regions, several characteristics with different specification limits and different sample sizes can be monitored in the same plot. The proposed graphical decision rule is also investigated with respect to power

  • 1169. Albing, Malin
    et al.
    Vännman, Kerstin
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mathematical Science.
    Elliptical Safety Region Plots for Cpk, Cpu and Cpl2008Report (Other academic)
  • 1170. Albing, Malin
    et al.
    Vännman, Kerstin
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mathematical Science.
    Process capability indices for one-sided specifications and skew zero-bound distributions2006Report (Other academic)
  • 1171. Albing, Malin
    et al.
    Vännman, Kerstin
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mathematical Science.
    Skewed zero-bound distributions and process capability indices for upper specifications2009In: Journal of Applied Statistics, ISSN 0266-4763, E-ISSN 1360-0532, Vol. 36, no 2, p. 205-221Article in journal (Refereed)
    Abstract [en]

    A common practical situation in process capability analysis, which is not well developed theoretically, is when the quality characteristic of interest has a skewed distribution with a long tail towards relatively large values and an upper specification limit only exists. In such situations it is not uncommon that the smallest possible value of the characteristic is 0 and this also is the best value to obtain. Hence a target value 0 is assumed to exist. We investigate a new class of process capability indices for this situation. Two estimators of the proposed index are studied and the asymptotic distributions of these estimators are derived. Furthermore we suggest a decision procedure useful when drawing conclusions about the capability at a given significance level, based on the estimated indices and their asymptotic distributions. A simulation study is also performed, assuming that the quality characteristic is Weibull distributed, to investigate the true significance level when the sample size is finite.

  • 1172. Albino, Björn
    Geofysiska parametermätningar på borrkärnor från typområdet Gideå2001Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 1173. Albinsdotter - Darehed, Inger
    et al.
    Nilsson, Anette
    Människors upplevelser av att leva med stomi: en litteraturstudie2005Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
  • 1174. Albl, Cenek
    PanCam Bundle Adjustment2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis investigated the method of Bundle Adjustment with special focus on constrained systems, such as panoramic cameras. SBA algorithm from Lourakis and Argyros was implemented in Matlab and its functionality was validated. A new algorithm was proposed and implemented based the original one, incorporating the constraints suited for PanCam-like cameras. This algorithm was evaluated on both synthetic and real datasets. The performance was thoroughly analyzed and compared to the original method in terms of accuracy of the reconstruction. For synthetic datasets, significant improvements have been observed and expressed quantitatively. Particular improvements in terms of visual appearance have been observed on real datasets. Results were elaborated and possibilities for further improvement have been proposed.

  • 1175. Albons, Birgitta
    et al.
    Gunnarsson, Ewa
    Söderberg, Inger
    På vinst och förlust: rapport om datorisering i USA1981Report (Other (popular science, discussion, etc.))
  • 1176. Alborz, Banafsheh
    Value-based adoption of mobile internet in Iran2010Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Regarding the ever-increasing number of cell phone subscribers, the situations of businesses are changing to mobile form. The trend of switching fashion of business is from traditional to electronic commerce and from that to mobile commerce. Mobile Internet adoption is one of the fundamental steps to mobile commerce implementation. This research studies the adoption of Mobile Internet as a one of new Information and Communication Technology (ICT) from the value point of view. While M-Internet principally provides the same services as stationary Internet, its acceptance rate is lower than stationary Internet. The reason probably is the cost of its usage. The adopters of M-Internet are individuals and the majority of them use it for personal purpose and the cost of voluntary usage is tolerated by individuals. Thus, for studying the adoption of M-Internet the famous Technology Acceptance Model (TAM) which has been used for explaining traditional technologies is not appropriate for the reason that most of those users and adopters are employees who use it for their work and the cost of requisite adoption is suffered and supported by the organization. To overcome this distinguishes among traditional technology and fresh one, we should consider the perceived value from the customer's point of view and this is possible via the Value-based model (VAM).This study applies the Value-based Adoption Model in M-Internet. For doing so, a survey has been presented on M-Internet users, questionnaires were distributed among them and the results analyzed based research questions. Finally, the conclusions and implications were prepared.

  • 1177. Albrechtsson, Helena
    et al.
    Renman, Annelie
    Utveckling av morgondagens kylskåpsinredning2004Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
  • 1178.
    Alcazar, Magnus
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    "Ideas are simple. Implementation is Hard.": En Fallstudie om Nyckelfaktorer för Implementering av Planeringssystem inom Hemtjänsten2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Background: Home care are a very common form of care and many prefer this form of care in front of hospitalized care. The home care service is therefore in need of a planning system in order to plan its work as efficiently as possible. Many of these implementations fail.

    Purpose: Many implementations in the home care service fail. The purpose of this paper is therefore to investigate what critical success factors project managers should focus on to achieve a successfull implementation.

    Method: This study has been conducted with a qualitative study as research method. A literature study was carried out by finding previous research in the field, which was then used as a theoretical framework. This was then compared with the empirical evidence acquired through semi-structured interviews with people with experience of implementations in the home care industry.

    Result: The result shows that the CSF’s that appeared in the literature study should also be used in practice. In addition, three new factors were identified

    Conclusion: All of the CSF’s presented in the literature study were reinforced by the interviews conducted with the informants in this study. References to how these should be used have also been developed. For example, the focus on the factor resources should primarily be put on the resource time.This study also concludes that depending on the type of organization it is about, such as small private companies, private medium-sized companies or municipal-owned businesses, focus should be on different CSF’s.

  • 1179.
    Al-Chalabi, Hussan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Life cycle cost analysis of the ventilation system in Stockholm's road tunnels2018In: Journal of Quality in Maintenance Engineering, ISSN 1355-2511, E-ISSN 1758-7832, Vol. 24, no 3, p. 358-375Article in journal (Refereed)
    Abstract [en]

    Purpose

    This study developed a practical economic replacement decision model to identify the economic lifetime of the ventilation system used by Trafikverket in its Stockholm tunnels.

    Design/methodology/approach

    The proposed data driven optimisation model considers operating and maintenance costs, purchase price and system resale value for a ventilation system consisting of 121 fans. The study identified data quality problems in Trafikverket’s MAXIMO database.

    Findings

    It found the absolute economic replacement time (ERT) of the ventilation system is 108 months but for a range of 100 to 120 months, the total cost remains almost constant. Sensitivity and regression analysis showed the operating cost has the largest impact on the ERT.

    Originality/value

    The results are promising; the company has the possibility of significantly reducing the LCC of the ventilation system by optimising its lifetime. In addition, the proposed model can be used for other systems with repairable components, making it applicable, useful, and implementable within Trafikverket more generally.

  • 1180.
    Al-Chalabi, Hussan
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Al-Douri, Yamur
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Lundberg, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Time Series Forecasting using ARIMA Model: A Case Study of Mining Face Drilling Rig2018Conference paper (Refereed)
    Abstract [en]

    This study implements an AutoregressiveIntegrated Moving Average (ARIMA) model to forecast totalcost of a face drilling rig used in the Swedish mining industry.The ARIMA model shows different forecasting abilities usingdifferent values of ARIMA parameters (p, d, q). However,better estimation for the ARIMA parameters is required foraccurate forecasting. Artificial intelligence, such as multiobjective genetic algorithm based on the ARIMA model, couldprovide other possibilities for estimating the parameters. Timeseries forecasting is widely used for production control,production planning, optimizing industrial processes andeconomic planning. Therefore, the forecasted total cost data ofthe face drilling rig can be used for life cycle cost analysis toestimate the optimal replacement time of this rig.

  • 1181.
    Al-Dahan, Saadi
    et al.
    Department of Geology, Faculty of Science, University of Kufa.
    Alabidi, Abdelkadhum
    Department of Geology, Faculty of Science, University of Kufa.
    Al-Ansari, Nadhir
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Knutsson, Sven
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Relationship between Selected Hydrochemical Parameters in Springs of Najaf Province, Iraq2015In: Engineering, ISSN 1947-3931, E-ISSN 1947-394X, Vol. 7, no 6, p. 337-346Article in journal (Refereed)
    Abstract [en]

    Several springs exist at the south-western desert of Iraq in Najaf Province at latitude 31˚00' -32˚15' and longitude 43˚30' - 44˚30'. They are almost parallel to Euphrates River on the eastern edge of western desert. General direction for the distribution of springs coincides with that of faults running northwest-southeast. The Hydrogen sulfide, temperature, pH and electrical conductivity were investigated in these springs. The analyses indicated that the concentration of H2S decreased from northwest toward southeast which is attributed to the escape of this gas to the atmosphere during the flow of groundwater near or on the earth surface. The surrounding geologic conditions did not affect the temperature and pH of the springs. Electrical conductivity showed an increase from northwest towards southeast which reflects dissolving more ions from the rocks of the aquifer. The electrical conductivity and hydrogen sulfide concentration had reverse relationship.

  • 1182.
    al-Dahan, Saadi
    et al.
    Department of Geology, Faculty of Science, University of Kufa.
    M., Hussain Hussain
    Department of Geology, Faculty of Science, University of Kufa.
    Al-Ansari, Nadhir
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Knutsson, Sven
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Hydrochemistry of springs, Najaf area, Iraq2015In: Journal of Environmental Hydrology, ISSN 1058-3912, E-ISSN 1996-7918, Vol. 23, article id 3Article in journal (Refereed)
    Abstract [en]

    Springs exist in southwestern Iraq at Najaf area in southwestern desert (latitude 31º 00 ̄ – 32º 15 ̄ and longitude 43º 30 ̄ – 44º 30 ̄). Two aquifers exist in the area. The first is composed of recent deposits while the second aquifer is of Miocene deposits. The latter is important because it contains huge quantities of groundwater. Water of these springs is slightly brackish and very hard. The predominant salt in the water of these springs is magnesium sulfate (MgSO4) and sodium chloride (NaCl). The water type is sulfate. Most of water springs (70%) are of marine water origin, while the minority (30%) are of continental water origin.

  • 1183. Aldeman, Sara
    et al.
    Antti, Helen
    Upplevelser av att leva med långvarig kroppslig smärta: en litteraturstudie2007Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
  • 1184.
    Aldenbo Rova, Tina
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences.
    Några nyp får man räkna med: En kvalitativ studie om hot och våld inom äldreomsorgen2016Independent thesis Basic level (degree of Bachelor), 180 HE creditsStudent thesis
    Abstract [sv]

    Syftet med uppsatsen var att beskriva de anställdas upplevelse av hot och våld samt få en fördjupad kunskap i hur verksamheten hanterar hot och våld. Detta ville jag göra för att bidra till en ökad kunskap om hur arbetssituationen kan se ut i äldreomsorgen. För att reda ut detta utförde jag en kvalitativ studie och intervjuade undersköterskor samt enhetschefer som alla arbetade på olika äldreboenden. Empirin analyserade jag med hjälp av tidigare forskning som visade på att hot och våld ökat främst inom vård-och omsorgsyrkena samt att hot och våld är ett dilemma för dessa yrkesgrupper. De arbetsmiljöföreskrifter jag använt mig av är systematiskt arbetsmiljöarbete samt våld och hot i arbetsmiljön. Vetenskapligt vedertagna teorier som jag använt mig av är Karaseks krav-kontroll och stödmodell samt Antonovskys begrepp KASAM.

    Samtliga informanter beskrev hot och våld som en individuell upplevelse från en uppkommen situation. Undersköterskorna liksom enhetscheferna kändetill i vilka situationer hot och våld uppstod. Rutinerna vad gäller riskbedömningar och handlingsplaner följs av alla, däremot fannsdet brister i avvikelserapporteringen trots att det var något som de ansåg som viktigt. Vidare visaderesultatet att samtliga informanter har lång erfarenhet av hot och våld samt att det är något som de kan hanterapå ett ansenligt sätt tack vare en lång och gedigen kunskap i bemötande. För att överhuvudtaget kunna hantera hot-och våldssituationer var det sociala stödet frånarbetskamraterna den viktigaste faktorn. Undersköterskorna kände sig trygga på arbetsplatsen trots hot och våld, förklaringen till det kan vara att de har en hög känsla av sammanhang i kombination med att arbetskraven samt egenkontrollen var höga. Hot ochvåld sågs inte direkt som ett arbetsmiljöproblem utan bedömdes vara omedvetna handlingar utförda av personer med exempelvis demenssjukdomar.

  • 1185.
    Aldenlöv, Jens
    et al.
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Business Administration and Industrial Engineering.
    Bergquist, Bjarne
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Business Administration and Industrial Engineering.
    Eriksson, Per-Erik
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Innovation and Design.
    Söderholm, Peter
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Business Administration and Industrial Engineering.
    Gustavsson Kärrbom, Tina
    KTH, Depteartment of Real Estate & Construction Management.
    Public procurement of railway infrastructure maintenance: a literature review2017In: Proceedings of the 9th Nordic Conference on Construction Economics and Organization / [ed] Buser, M; Lindahl, G; Raisanen, C, Lyngby: Polyteknisk Boghandel og Forlag, 2017, p. 10-21Conference paper (Refereed)
    Abstract [en]

    The maintenance of railway infrastructure has in several instances been changed from government-based to being based on public procurement, with varying degrees of flexibility for the contractor to design their maintenance work. The purpose of-giving contractors a larger freedom of choice of how to perform maintenance is to stimulate them to innovate and develop their maintenance processes. Since the contracts differ in between and there are changes in government policies over time that affects both existing and new contracts, a comparison between different contracts becomes challenging. A literature review has been conducted to understand the change in procurement strategy and how to encourage contractors to innovate. The research questions include: What procurement strategies are there? How is maintenance evaluated? How does procurement affect the innovation opportunities for entrepreneurs? The literature review focuses on railway maintenance and contract design between client and contractor. In total, 17 articles matched the search criteria and were selected for the review. To have successful maintenance service, five articles suggested partnering as a strategy with common goals in combination with good communication during the entirety of the contract. When selecting incentive plan, four articles mentions that a focus on performance-based incentives in combination with risk management is better rather than actual payment schemes. The reason being that payment is often the main cause of conflicts between client and contractor. The scientific literature suggests that improvement in incentives improves quality of maintenance, decreases delays and technical failures. The conclusion from the literature review is that partnering in railway maintenance is considered successful. With accurate knowledge about railway assets the incentive plan becomes accurate which reduces costs. The literature review is a part of a research project with an overall goal to develop a model to guide the selection of appropriate type of procurement strategy, contract and control of maintenance for a more sustainable railway system.

  • 1186.
    Aldenlöv, Jens
    et al.
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Business Administration and Industrial Engineering.
    Bergquist, Bjarne
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Business Administration and Industrial Engineering.
    Eriksson, Per-Erik
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Innovation and Design.
    Söderholm, Peter
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Business Administration and Industrial Engineering.
    Karrbom Gustavsson, Tina
    KTH Royal Institute of Technology, Real Estate and Construction Management .
    Public procurement of railway infrastructuremaintenance: a literature review2017Conference paper (Refereed)
    Abstract [en]

    The maintenance of railway infrastructure has in several instances been changed from government-based to being based on public procurement, with varying degrees of flexibility for the contractor to design their maintenance work. The purpose of-giving contractors a larger freedom of choice of how to perform maintenance is to stimulate them to innovate and develop their maintenance processes. Since the contracts differ in between and there are changes in government policies over time that affects both existing and new contracts, a comparison between different contracts becomes challenging. A literature review has been conducted to understand the change in procurement strategy and how to encourage contractors to innovate. The research questions include: What procurement strategies are there? How is maintenance evaluated? How does procurement affect the innovation opportunities for entrepreneurs?

    The literature review focuses on railway maintenance and contract design between client and contractor. In total, 17 articles matched the search criteria and were selected for the review. To have successful maintenance service, five articles suggested partnering as a strategy with common goals in combination with good communication during the entirety of the contract. When selecting incentive plan, four articles mentions that a focus on performance-based incentives in combination with riskmanagement is better rather than actual payment schemes. The reason being that payment is often themain cause of conflicts between client and contractor. The scientific literature suggests that improvement in incentives improves quality of maintenance, decreases delays and technical failures. The conclusion from the literature review is that partnering in railway maintenance is considered successful. With accurate knowledge about railway assets the incentive plan becomes accurate which reduces costs.

    The literature review is a part of a research project with an overall goal to develop a model to guide the selection of appropriate type of procurement strategy, contract and control of maintenance for a moresustainable railway system.

  • 1187. Aldenlöv, Maria
    et al.
    Lidén, Ellen
    Sjuksköterskans upplevelse av att vara patient: En analys av narrativer2014Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
  • 1188.
    Aldenlöv, Maria
    et al.
    Luleå University of Technology, Department of Health Sciences.
    Lundbäck, Rebecca
    Luleå University of Technology, Department of Health Sciences.
    Operationssjuksköterskors uppfattningar av operation med vaken patient: En kvantitativ enkätstudie2017Independent thesis Advanced level (degree of Master (One Year)), 40 credits / 60 HE creditsStudent thesis
    Abstract [sv]

    Att gå från att vara en person till att bli en patient innebär att livet kan förändras. Sårbarhet, utsatthet, förlust av kontroll, rädsla för det okända och stress är vanligt förekommande känslor i samband med operation. Patienter har beskrivit att de upplever operation som att balansera mellan att vara delaktig och osynlig, inte vilja störa men samtidigt bli sedd, samt att känna sig ensam, övergiven och exponerad. Som blivande operationssjuksköterskor är det viktigt att ha kunskap om patientens upplevelse, samt reflektera över det egna arbetet. Flertalet studier har fokuserat på patientens upplevelse och visar att personalens bemötande och kommunikation är avgörande för patientens upplevelse. Studies syfte var att kartlägga operationssjuksköterskors uppfattningar av operation med vaken patient. Studien var en tvärsnittsstudie med kvantitativ ansats, och tillämpade enkätformulär som datainsamlingsmetod med bekvämlighetsurval. Analysen genomfördes med deskriptiv analys, samt hypotesprövning för att stärka resultatet. Resultatet presenterades med tabeller, grafer och text. Den öppna kvalitativa frågan sammanställdes i kategorier och presenterades med citat. Resultatet visade att operationssjuksköterskor uppfattade att vid en operation med vaken patient skedde förändringar av kommunikationen och bemötandet, samt att operationssalen uppfattades lugnare och mer harmonisk när musik spelades. Författarna rekommenderar fortsatta studier för djupare förståelse av operationssjuksköterskors uppfattningar av förändringar av kommunikationen och bemötandet vid operation med vaken patient, samt musikens påverkan. Resultatet från denna studie kan användas som reflektionsstöd dels hos arbetsgivaren och dels hos den enskilda operationspersonalen, samt som stöd vid handledning av studenter och nyutbildade operationssjuksköterskor. 

  • 1189. Aldgård, Thorbjörn
    et al.
    Johansson, David
    Utveckling av testrigg för mätning av däckfriktion mot vinterväglag2006Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 1190.
    Al-Doori, Noor
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences.
    Nedskrivningsprövning av goodwill enligt IAS 36: En jämförande studie av dess efterlevnad i börsnoterade bolag på large cap-listan under åren 2005–20152017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    More than 10 years ago, IFRS 3 / IAS 36 was introduced and it became mandatory for all

    listed companies in Sweden to report goodwill. The problem is that IAS 36 is a complicated

    rule and studies show a low level of compliance. The companies are trying to avoid applying

    the rule because companies think it gives a negative image of the companies. This study aims

    at describing how well listed companies in the telecommunications industry comply with IAS

    36 and comparing how it changes over time. This study examines the annual reports of all

    four companies listed on the large-cap list in the telecommunications industry on a

    quantitative method. This is to choose a standard which is IAS 36 p. 134 with a quantitative

    method. The results are presented in tables and diagrams. The study shows that the level of

    compliance is very different among the companies and that the degree of compliance is

    improved over time.

  • 1191. Aldoson, Martin
    Effekt av telerehabilitering vid multipel skleros: En litteraturöversikt2016Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
  • 1192.
    Al-Douri, Yamur
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Hamodi, Hussan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Data imputing using genetic algorithms (GA): A case study of cost data for tunnel fans2017Conference paper (Refereed)
  • 1193.
    Al-Douri, Yamur K.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Information assurance for maintenance of railway track2016Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Railway traffic is steadily increasing, having a negative impact on maintenance and resulting in decreased track availability, comfort, and safety. Swedish railway track maintenance mostly focuses on the actual track condition via a nationwide condition-based maintenance (CBM) strategy. For maintenance to be conducted in an appropriate way, data on the actual track condition must be accurate; furthermore, those data need to be converted into accurate information for maintenance decisions. An information assurance (IA) framework has the potential to deal with the system risks from a technical perspective. The framework is a guideline that can be implemented within CBM to understand both condition monitoring data behaviour and the information processing used to reach maintenance decisions.This research investigates ways of an information assurance (IA) framework can be implemented in the following CBM steps: data collecting, data processing and making maintenance decisions on Swedish railway. The framework can be used to understand data behaviour, information processing and the communication between information layers for decisions at organisation, infrastructure and data/information levels. The research uses both qualitative and quantitative methods to investigate critical information data, parameters, and problems and to suggest which areas need improvement. Quantitative analysis of the Swedish track geometry database reveals specific information about the behaviour of the railway data and their processing to make maintenance decisions.A case study shows how certain sections of a railway track are monitored and evaluates maintenance practices on those sections. The study finds several different types of measurements are taken using several different measurement systems. It is difficult to integrate these data for proper processing. In addition, there are problems of incomplete or irregular data; this affects the derivation of information and the use of models to understand track irregularities.Given the problems of data processing and subsequent decision making, the study suggests implementing an IA framework with CBM. The study checks the achievement of three IA principles in the existing data: authenticity, integrity and availability. The results show data have problems of authenticity and integrity, something also mentioned by the stakeholders in interviews. In particular years and on certain track sections, CM data are more than 5 percent incomplete, significantly affecting analysis. Incomplete track measurement data reach as high as 63 percent for the parameters of standard deviation (STD), longitudinal level and STD cooperation. Inaccurate measured values for alignment long wavelength within certain speed limits reach as high as 71 percent. These indicators are important for calculating track quality but are either incomplete or incorrect, negatively affecting the calculation of the Q-value and estimations of the track quality. This, in turn, negatively affects the maintenance decisions. Using information assurance will increase the system performance by permitting stakeholders to make accurate decisions.The suggested information assurance framework can discover technical problems but it needs to be improved using technologies, techniques and services to ensure complete and accurate data are available to be processed for maintenance decisions.

  • 1194.
    Al-Douri, Yamur K.
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Al-Jumaili, Mustafa
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Karim, Ramin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Information security in e-maintenance: a study of Scada security2012Conference paper (Refereed)
    Abstract [en]

    eMaintenance solutions are spreading increasingly due to the continuous evolution in the different Information and Communication Technology (ICT) tools. In general, most of the available eMaintenance solutions are depending on Internet infrastructure what makes them vulnerable to all security threats that affect the Internet. One of the important eMaintenance solutions is Supervisory Control and Data Acquisition (SCADA) system as it has been used in most of the industrial processes. SCADA systems were designed without security considerations as they were mainly installed into isolated networks. Nowadays, SCADA systems are mainly connected to Internet and other networks. Therefore, SCADA systems have been exposed to wide range of network security threats. Hence, SCADA security has become an important aspect that needs to be investigated. In this paper, a study of SCADA security issues will be done. The main contribution of this paper is to address SCADA security issues and challenges related to eMaintenance.

  • 1195.
    Al-Douri, Yamur K.
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Hamodi, Hussan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Data imputing using generic algorithms (GA)2017In: Mine Planning and Equipment Selection (MPES 2017): Proceeding of the 26th International Symposium on Mine Planning and Equipment Selection Luleå, Sweden, August 29-31, 2017 / [ed] Behzad Ghodrati, Uday Kumar, Håkan Schunnesson, Luleå: Luleå tekniska universitet, 2017, p. 205-208Conference paper (Refereed)
  • 1196.
    Al-Douri, Yamur K.
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Hamodi, Hussan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Lundberg, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Time Series Forecasting using a Two-level Multi-objective Genetic Algorithm: A case study of cost data for tunnel fans2018In: Algorithms, ISSN 1999-4893, Vol. 11, no 8, article id 123Article in journal (Refereed)
    Abstract [en]

    The aim of this study is to develop a novel two-level multi-objective genetic algorithm (GA) to optimize time series forecasting data for fans used in road tunnels by the Swedish Transport Administration (Trafikverket). The first level is for the process of forecasting time series cost data, while the second level evaluates the forecasting. The first level implements either a multi-objective GA based on the ARIMA model or based on the dynamic regression model. The second level utilises a multi-objective GA based on different forecasting error rates to identify a proper forecasting. Our method is compared with the ARIMA model only. The results show the drawbacks of time series forecasting using the ARIMA model. In addition, the results of the two-level model show the drawbacks of forecasting using a multi-objective GA based on the dynamic regression model. A multi-objective GA based on the ARIMA model produces better forecasting results. In the second level, five forecasting accuracy functions help in selecting the best forecasting. Selecting a proper methodology for forecasting is based on the averages of the forecasted data, the historical data, the actual data and the polynomial trends. The forecasted data can be used for life cycle cost (LCC) analysis.

  • 1197.
    Al-Douri, Yamur K.
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Hamodi, Hussan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Zhang, Liangwei
    Department of Industrial Engineering, School of Mechanical Engineering, Dongguan University of Technology, 523808 Dongguan, China.
    Data clustering and imputing using a two-level multi-objective genetic algorithms (GA): A case study of maintenance cost data for tunnel fans2018In: Cogent Engineering, ISSN 2331-1916, Vol. 5, no 1, p. 1-16, article id 1513304Article in journal (Refereed)
    Abstract [en]

    Data clustering captures natural structures in data consisting of a set of objects and groups similar data together. The derived clusters can be used for scale analysis and to posit missing data values in objects, as missing data have a negative effect on the computational validity of models. This study develops a new two-level multi-objective genetic algorithm (GA) to optimize clustering in order to redact and impute missing cost data for fans used in road tunnels by the Swedish Transport Administration (Trafikverket). The first level uses a multi-objective GA based on fuzzy c-means to cluster cost data objects based on three main indices. The first is cluster centre outliers; the second is the compactness and separation ( ) of the data points and cluster centres; the third is the intensity of data points belonging to the derived clusters. Our clustering model is validated using k-means clustering. The second level uses a multi-objective GA to impute the missing cost redacted data in size using a valid data period. The optimal population has a low , 0.1%, and a high intensity, 99%. It has three cluster centres, with the highest data reduction of 27%. These three cluster centres have a suitable geometry, so the cost data can be partitioned into relevant contents to be redacted for imputing. Our model show better clustering detection and evaluation compared with k-means. The amount of missing data for the two cost objects are: labour 57%, materials 81%. The second level shows highly correlated data (R-squared 0.99) after imputing the missing data objects. Therefore, multi-objective GA can cluster and impute data to derive complete data that can be used for better estimation of forecasting.

  • 1198.
    Al-Douri, Yamur K.
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Karim, Ramin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Parida, Aditya
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Kumar, Uday
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Model-based security system for data acquisition in e-maintenance using artificial immune system and cloud computing2012In: International Journal of COMADEM, ISSN 1363-7681, Vol. 15, no 4, p. 26-37Article in journal (Refereed)
    Abstract [en]

    eMaintenance solutions are extensively used by the industry today. eMaintenance is an emerging technology aimed to support the industry to achieve effectiveness and efficiency in their maintenance process through enhanced use of Information and Communication Technology (ICT) . One of the essential components is an eMaintenance solution is data acquisition. Supervisory Control and Data Acquisition (SCADA) has been used to manage data acquisition is many industrial systems. Nowadays, modern SCADA systems are available through internet and other networks via IP protocol. An increased use of internet–based solution requires appropriate management approaches to improve the safety and security aspects of a system. Hence, this paper suggests a new security model based security for SCADA systems through Cloud computing and Artificial Immune System (AIS). Furthermore, the paper provides AIS, which is based on Decision Tree (C4.5 algorithm) using clustered feature set. The features set are selected from NSL-KDD cup. It is a new version of KDD dataset. As a result, two Antibodies are generated (that could recognize Normal and Antigen). After applying the resulted antibodies on the testing data set, the outputs are Normal, Antigen, and Unknown. Finally it is treated with Unknown as Antigen. As a result, high accuracy of the suggested model reaches 96.3%.

  • 1199.
    Al-Douri, Yamur K.
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Pangracious, Vinod
    Department of Electrical and Computer Engineering, American University in Dubai,.
    Al-Doori, Mulhim
    Department of Electrical and Computer Engineering, American University in Dubai.
    Artifical Immune System Using Genetic Algorithm And Decision Tree2016In: International Conference on Bio-engineering for Smart Technologies (BioSMART) 2016, Piscataway, NJ: IEEE, 2016, p. 1-4, article id 7835603Conference paper (Refereed)
    Abstract [en]

    Artificial immune system (AIS) is considered as an adaptive computational intelligence method that could be used for detecting and preventing current computer network threats. AIS generates Antibodies (self) competent in recognizing Antigen (non-self), which is considered as an anomaly technique. This paper aims to develop artificial immune system (AIS) that consists of two levels. Level one is developed using Genetic Algorithm, while level two is developed using C4.5 decision tree algorithm. The proposed system trained with clustered features that are selected from NSL-KDD cup data-set. Each level produces two antibodies (that could recognize Normal and Antigen access-records). The recognition accuracy of the developed system reaches 96%. The behavior of each level is studied. The best feature-set that suits each level is specified.

  • 1200.
    Al-Douri, Yamur K.
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Tretten, Phillip
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    A critical review of Information Assurance (IA) framework forcondition-based maintenance of railway tracks2017In: Risk, Reliability and Safety: Innovating Theory and Practice - Proceedings of the 26th European Safety and Reliability Conference, ESREL 2016 / [ed] Walls L.,Revie M.,Bedford T, London: CRC Press, 2017, p. 1072-1078Conference paper (Refereed)
    Abstract [en]

    Railway maintenance is faced with increasing demands, including the need to improve service.Data measuring the track state and suitable models or applications are needed to make good maintenancedecisions. This critical review paper investigates many research papers on the use of information assurance (IA)within condition-based maintenance (CBM) on a railway track. An IA framework sheds light on the data andinformation used to make maintenance decisions. The paper considers work on data processing and decisionmakingin CBM. The results show condition monitoring suffers from an inability to determine exact positioningon the track; some data are inaccurate or unavailable. Existing studies have not adequately dealt with data contentor the various technologies used. They focus on integrity, availability, authentication, authorisation and accuracy,but do not consider other IA principles important to understand data.CBMmodels and algorithms have difficultyunderstanding degradation models, and data problems mean it is difficult to make good decisions. There is alack of long term maintenance plans. Models also need to be integrated for more realistic but not necessarilyoptimum solutions and to ensure practical predictions of maintenance. Some models focus on degradation, othersconsider prediction, and still others calculate the maintenance cost; it is difficult to combine these. Overall, dataare inaccurate, there is no testing phase using realistic data, and existing models are insufficient. This has anegative impact on maintenance decisions.

21222324252627 1151 - 1200 of 62955
CiteExportLink 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