Change search
Refine search result
35363738394041 1851 - 1900 of 62973
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.
  • 1851.
    Al-Turjman, Fadi M.
    et al.
    Department of Computer Engineering, Middle East Technical University, Northern Cyprus Campus.
    Imran, Muhammad
    College of Computer and Information Sciences, King Saud University.
    Vasilakos, Athanasios
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Value-Based Caching in Information-Centric Wireless Body Area Networks2017In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 17, no 1, article id 181Article in journal (Refereed)
    Abstract [en]

    We propose a resilient cache replacement approach based on a Value of sensed Information (VoI) policy. To resolve and fetch content when the origin is not available due to isolated in-network nodes (fragmentation) and harsh operational conditions, we exploit a content caching approach. Our approach depends on four functional parameters in sensory Wireless Body Area Networks (WBANs). These four parameters are: age of data based on periodic request, popularity of on-demand requests, communication interference cost, and the duration for which the sensor node is required to operate in active mode to capture the sensed readings. These parameters are considered together to assign a value to the cached data to retain the most valuable information in the cache for prolonged time periods. The higher the value, the longer the duration for which the data will be retained in the cache. This caching strategy provides significant availability for most valuable and difficult to retrieve data in the WBANs. Extensive simulations are performed to compare the proposed scheme against other significant caching schemes in the literature while varying critical aspects in WBANs (e.g., data popularity, cache size, publisher load, connectivity-degree, and severe probabilities of node failures). These simulation results indicate that the proposed VoI-based approach is a valid tool for the retrieval of cached content in disruptive and challenging scenarios, such as the one experienced in WBANs, since it allows the retrieval of content for a long period even while experiencing severe in-network node failures.

  • 1852. Aludden, Johan
    Att hitta stora primtal2002Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 1853. Alvaeus, Niklas
    Trafiksäkerhetsaspekter på stödremsan och dess utformning1999Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 1854.
    Alvarenga, Rodrigo A.F.
    et al.
    Ghent University, Belgium.
    Dewulf, Jo
    Ghent University, Belgium.
    Guinée, Jeroen
    Leiden University, the Netherlands.
    Schulze, Rita
    Leiden University, the Netherlands.
    Weihed, Pär
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Bark, Glenn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Drielsma, Johannes
    Euromines, Belgium.
    Towards product-oriented sustainability in the (primary) metal supply sector2019In: Resources, Conservation and Recycling, ISSN 0921-3449, E-ISSN 1879-0658, Vol. 145, p. 40-48Article in journal (Refereed)
    Abstract [en]

    Consideration of sustainable supply of (primary) metals is increasingly influencing the policy agenda of western societies. Environmental sustainability can be managed from different perspectives, including a site-oriented one (strongly used by the mining sector) and a product-oriented one (as with life cycle assessment). The objectives of this article are to analyse and discuss the differences in these perspectives; to discuss potential benefits to the metal/mining sector of also considering the product-oriented perspective; and to propose ways for a smooth implementation. We made use of literature and expert knowledge, on top of interviews with different stakeholders, to identify why and how these perspectives are (not) used in the metal/mining sector. Moreover, we identified three key concerns related to the implementation of a product-oriented perspective in the sector (e.g., use of unrepresentative life cycle inventory (LCI) datasets for metal-based products) and proposed three corrective actions for all of them (e.g., increase the quantity and quality of LCI). Finally, we discuss how the corrective actions could be implemented in the sector in a smooth way and some potential benefits from its implementation.

  • 1855.
    Alvarez Cabrera, Tanya
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences.
    SBW Feedback: Design of feedback system for increased usability in monostable SBW shifters2017Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Electromechanical shift-by-wire car transmission systems make way for new innovative shifter designs such as monostable shifters that spring back to a starting position after a gear has been chosen. Unfortunately the radical change in the communication between the user and shifter has resulted in accidents due to incorrect gear selection. The inadequate usability of the monostable shifters can be attributed to the feedback it provided to users.

     

    The aim of the thesis project was to develop a feedback concept that would improve the usability of a monostable shifter and to study if auditory feedback could be introduced to vehicle systems. By implementing design theory, benchmarking and various creativity methods five concepts with feedbacks in different modalities were developed. The concepts were evaluated in a usability study that involved 25 test participants. A review of the observations from the usability study along with an analysis of the interviews and collected data resulted in the final VRA concept. VRA was a multimodal concept with permanent visual feedback and optional auditory feedback. The shifting pattern was shown on the instrument cluster where the active gear was highlighted through light intensity, color and shape contrasts. The solid blue block, within which the abbreviation for the active gear was displayed, could be seen in the peripheral view. It was perceived as calm and helped the users navigate the shifter. A female machine voice that had a Swedish pronunciation was chosen as the auditory feedback to accompany the “P”, “R” and “D” gear selections. None of the users were indifferent towards the auditory feedback, some perceived it as caring while others found it annoying. Since the analysis did not indicate that auditory feedback was crucial, the VRA concept included an option to turn on or off the sound.

     

    Monostable shifters behave differently compared to traditional polystable shifters, therefore with the changes in the physical movement the communication must also be reviewed. It is recommended to include the shifting pattern on the instrument cluster together with monostable shifters, as it makes up for the loss of the visual and haptic information from the physical shifter. Although the usability study showed that auditory feedback was not necessary, improvements were observed among people who favored it. The auditory information would most likely be better received if earcons were implemented instead of speech. 

  • 1856. Alvarez Garcia-Bobia, Luis
    et al.
    Garcia Cesa, Victor Jose
    A Mobile Web 2.0 community service based on near-field communication2008Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Similar to the adoption of the Internet during the ‘90s‘, consumer demand is influencing companies to adopt mobile as a new channel for communications, marketing, service delivery and payment. Internet adoption started with companies providing basic information, which quickly evolved into service delivery, marketing and e-commerce. The same phenomenon and adoption curve is unfolding in the mobile world today, as consumers are demanding information and media whenever and wherever they need it. As a result, companies are looking for new ways to satisfy this increasingly mobile consumer base. Moreover, the arrival of Web 2.0 has led to radical changes as regards not only technical specifications of the net, but in the ways both software developers and end-users use the Web. The next step is now to have Web 2.0 technology implemented on mobile platforms, since it will lead to a further development of them, and will make group communication systems accessible for almost everyone and everywhere, opening at the same time the door for a huge new upcoming market. This thesis focuses on the idea of extending social relationships created in the Web to portable devices, thus making it able for the people to communicate and interact with each other regardless of where they are. These tasks can be carried out by platforms that give support and services to mobile devices through the net. They will also allow people to meet and share experience in new ways, even though they are not always easy to use, especially not with mobile terminals that have limited capabilities. In this aspect, it is important to minimize set up time, since it is always the bottleneck of a communication process. Regarding that, one communication technology which a lot of research is being done in nowadays is NFC (Near Field Communication). It has limited range, but on the other hand its set up time is much faster than other existent technologies, such as Bluetooth. Since NFC enables quick connection establishment it could be a suitable technology to be applied in Social Network building and extending purposes. As a proof of concept, a mobile Social Network platform has been developed with the purpose of providing Social-Network-related services to cell phone common users, such as profiles and users management, storage of relationships between users, privileges and privacy control, multimedia sharing services, etc. In addition of using NFC for building social networks, the platform also takes advantage of third-party APIs offered by external social networks to access them. As for Near Field Communication technology, it has been used in the service maybe where it suited the most, provided its fast connection capabilities, that is friends adding. Finally a solid, modular, and easily extensible prototype has been built. The user can enjoy common social network services, at least in a basic way. Some other services considered to be interesting were added as well. As for future work, next step could be adding innovative features taking advantage of the Web 2.0 possibilities, since the platform base is already implemented.

  • 1857.
    Alvarez, Manuel
    et al.
    Universidad Simón Bolívar, Caracas.
    Bermúdez, Juan
    Universidad Simón Bolívar, Caracas.
    Marginal pricing via penalty factors in the Venezuelan hydrothermal system2006In: 2006 IEEE PES Transmission and Distribution Conference and Exposition: Latin America, TDC'06, Piscataway, NJ: IEEE Communications Society, 2006, article id 4104756Conference paper (Refereed)
    Abstract [en]

    The work shown next deals with the definition of nodal marginal prices, in the context of an economic dispatch solution with transmission losses. The losses are incorporated through penalty factors obtained from line distribution factors, using a linearization process. This study is applied to the hydrothermal venezuelan system, considering plants with regulation capability and run-of-river dams. The objective function to be minimized includes present and future thermal costs. In addition, a discussion is given about the correct location of the slack node, in order to get similar results to these associated to an OPF solution. © 2006 IEEE.

  • 1858.
    Alvarez, Manuel
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Bollen, Math
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Rönnberg, Sarah
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Zhong, Jin
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Gil-de-Castro, Aurora
    University of Cordoba, Electronics and Electronic Technology Area, University of Cordoba.
    A Smart Distribution Toolbox for Distribution System Planning2015Conference paper (Refereed)
    Abstract [en]

    The distribution system planner should be able to coordinate smart grid solutions in order to find cost effective expansions plans. These plans should be able to deal with new added system uncertainties from renewable production and consumers while guaranteeing power quality and availability of supply. This paper proposes a structure for distribution systems planning oriented to help the planner in deciding how to make use of smart solutions for achieving the described task. Here, the concept of a system planning toolbox is introduced and supported with a review of relevant works implementing smart solutions. These are colligated in a way that the system planner can foresee what to expect with their combined implementation. Future developments in this subject should attempt to theorize a practical algorithm in an optimization and decision making context.

  • 1859.
    Alvarez, Manuel
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Jabr, Rabih
    American University of Beirut.
    Cossent, Rafael
    Universidad Pontificia de Comillas.
    Frías, Pablo
    Universidad Pontificia de Comillas.
    Zhong, Jin
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Capacity Mechanisms for Distribution Network Expansion Planning2019In: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208Article in journal (Refereed)
  • 1860.
    Alvarez Perez, Manuel Alejandro
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Stochastic Planning of Smart Electricity Distribution Networks2017Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The penetration of intermittent Distributed Generation (DG) brought additional uncertainty to the system operation and planning. To cope with uncertainties the Distribution System Operator (DSO) could implement several strategies. These strategies range from the inclusion of smart technologies which will increment system’s flexibility and resiliency, to improvements in forecasting, modeling, and regulatory pledge that will facilitate the planning activity. Regardless of the nature of the solutions, they could be collected in a sort of toolbox. The planner will access the toolbox to conform cost effective plans, better able to deal with any uncertainty. The present work will address the problem of distribution system planning under uncertainties, considering smart solutions along with traditional reinforcements, in the short-term lead time up to 3 years ahead. The work will be focused on three aspects that are the cornerstones of this work:

     • A planning facilitating strategy: Distribution Capacity Contracts (DCCs).

     • A flexibility enabler technology: Energy Storage.

     • A binding methodology: Multistage Stochastic Programming. Stochastic dual dynamic programming (SDDP). 

    Under the present directive of the European Parliament concerning common rules for the internal market in electricity, distribution companies are not allowed to own DG but entitled to include it as a planning option to differ investment in traditional grid reinforcements. An evaluation of the regulatory context will lead this work to consider DCCs as a planning alternative available in the toolbox. The impact of this type of contract on the remuneration of the DG owner will be assessed in order to provide insight on its willingness to participate. The DCCs might aid the DSO to defer grid i ii investments during planning stages and to control the network flows during operation. 

    Given that storage solutions help to match in time production from intermittent sources with load consumption, they will play a major role in dealing with uncertainties. A generic storage model (GSM) based on a future cost piecewise approximation will be developed. This model inspired by hydro-reservoirs will help assessing the impact of storage in planning decisions. This model will be tested by implementing it in short-term hydro scheduling and unit commitment studies. 

    To trace a path towards the future of this research work, a discussion on the planning problem formulation, under consideration of the lead time, the expansion options, the smart strategies, and the regulatory framework will be presented. Special focus will be given to multistage stochastic programming methods and in particular to the SDDP approach.

  • 1861.
    Alvarez Perez, Manuel Alejandro
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Rönnberg, Sarah
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Bermúdez, Juan
    Universidad Simón Bolívar.
    Zhong, Jin
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. The University of Hong Kong.
    Bollen, Math
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    A Generic Storage Model Based on a Future Cost Piecewise-Linear Approximation2019In: IEEE Transactions on Smart Grid, ISSN 1949-3053, E-ISSN 1949-3061, Vol. 10, no 1, p. 878-888Article in journal (Refereed)
    Abstract [en]

    This work presents a generic storage model (GSM) inspired by the scheduling of hydraulic reservoirs. The model for steady state short-term (ST) operational studies interlaces with the long-term (LT) energy scheduling through a piecewise-linear Future Cost Function (FCF). Under the assumption that a Stochastic Dual Dynamic Programming (SDDP) approach has been used to solve the energy schedule for the LT, the FCF output from that study will be processed to obtain an equivalent marginal opportunity cost for the storage unit. The linear characteristic of a segment of the future cost function (FCF) will allow a linear modeling of the storage unit production cost. This formulation will help to coordinate the renewable resource along with storage facilities in order to find the optimal operation cost while meeting end-point conditions for the long-term plan of the energy storage. The generic model will be implemented to represent a battery storage and a pumped-hydro storage. A stochastic unit commitment (SUC) with the GSM will be formulated and tested to assess the day-ahead scheduling strategy of a Virtual Power Plant (VPP) facing uncertainties from production, consumption, and market prices.

  • 1862.
    Alvarez Perez, Manuel Alejandro
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Rönnberg, Sarah
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Bermúdez, Juan
    Universidad Simón Bolívar.
    Zhong, Jin
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Bollen, Math
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    A Hydro-Reservoir Generic Storage Model for Short-Term Hydrothermal Coordination2017In: IEEE PES PowerTech Manchester 2017: towards and beyond sustainable energy systems, 2017, Piscataway, NJ: Institute of Electrical and Electronics Engineers (IEEE), 2017, article id 7980882Conference paper (Refereed)
    Abstract [en]

    This work presents a linear solution for the short-term hydro-thermal scheduling problem linked to long-term conditions through a piecewise-linear Future Cost Function (FCF). Given end-point conditions to conform long-term water releases, and given actual reservoir conditions, a segment of a pre-built piecewise future cost function will be chosen. The linear characteristic of the FCF segment will allow a linear modeling of the hydro-power plant, in a similar fashion as a thermal unit with an equivalent marginal opportunity cost. A short-term hydro thermal coordination problem will be formulated considering parallel and cascaded hydro-reservoirs. Three study cases involving different reservoir configurations and scenarios will be computed to test the model. The results of this model mimics coherently the future-cost hydro-thermal coordination problem for the different configurations tested. Given similarities with other forms of energy storage, a new theoretical model for generic storage will be proposed and discussed.

  • 1863.
    Alvarez Perez, Manuel Alejandro
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Rönnberg, Sarah
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Bermúdez, Juan
    Department of Energy Conversion and Transport, Simón Bolívar University.
    Zhong, Jin
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Bollen, Math
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Reservoir-Type Hydropower Equivalent Model Based on a Future Cost Piecewise Approximation2018In: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 155, p. 184-195Article in journal (Refereed)
    Abstract [en]

    The long-term (LT) scheduling of reservoir-type hydropower plants is a multistage stochastic dynamic problem that has been traditionally solved using the stochastic dual dynamic programming (SDDP) approach. This LT schedule of releases should be met through short-term (ST) scheduling decisions obtained from a hydro-thermal scheduling that considers uncertainties. Both time scales can be linked if the ST problem considers as input the future cost function (FCF) obtained from LT studies. Known the piecewise-linear FCF, the hydro-scheduling can be solved as a one-stage problem. Under certain considerations a single segment of the FCF can be used to solve the schedule. From this formulation an equivalent model for the hydropower plant can be derived and used in ST studies. This model behaves accordingly to LT conditions to be met, and provides a marginal cost for dispatching the plant. A generation company (GENCO) owning a mix of hydro, wind, and thermal power will be the subject of study where the model will be implemented. The GENCO faces the problem of scheduling the hydraulic resource under uncertainties from e.g. wind and load while determining the market bids that maximize its profit under uncertainties from market prices. A two-stage stochastic unit commitment (SUC) for the ST scheduling implementing the equivalent hydro model will be solved.

  • 1864.
    Alvarez Perez, Manuel Alejandro
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Rönnberg, Sarah
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Cossent, Rafael
    Universidad Pontificia de Comillas.
    Zhong, Jin
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Bollen, Math
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Regulatory Matters Affecting Distribution Planning With Distributed Generation2017In: CIRED - Open Access Proceedings Journal, E-ISSN 2515-0855, Vol. 2017, no 1, p. 2869-2873Article in journal (Refereed)
    Abstract [en]

    Under the present European directive concerning common rules for the internal market in electricity, distribution companies are not allowed to own distributed generation (DG) but encouraged to include it as a planning option to defer investment in traditional grid reinforcements. Distribution system operators (DSOs) have used the provision of capacity contracted to DG as a viable alternative under current regulatory arrangements. Here, the topics bonding DSOs and DG owners under the present regulation will be explored and a planning structure that considers distribution capacity contracts as a planning option will be proposed. This will serve as a road map for DSOs to implement its preferred planning tools in an optimisation context, considering costs of investment, reliability, operation, and capacity provision while complying with current regulation.

  • 1865.
    Alvarez Perez, Manuel Alejandro
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Rönnberg, Sarah
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Cossent, Rafael
    Universidad Pontificia de Comillas.
    Zhong, Jin
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Bollen, Math
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Remuneration Assessment of a VPP Providing Distribution Capacity Services2017In: IEEE PES PowerTech Manchester 2017: towards and beyond sustainable energy systems, Piscataway, NJ: Institute of Electrical and Electronics Engineers (IEEE), 2017, article id 7980881Conference paper (Refereed)
    Abstract [en]

    A Distribution System Operator (DSO) might consider a capacity contract as a planning alternative to defer grid investments. A Virtual Power Plant (VPP) might be able to provide such capacity and change its production as requested by the DSO. This article presents an assessment of the impact of this type of distribution capacity contract (DCC) on VPP's remuneration. This assessment is done by comparing the optimal production / bidding strategy which maximize its profit, under presence or absence of these contracts. The impact of intermittent generation and storage while evaluating these scenarios will be investigated as well. A stochastic unit commitment will be used to determine the VPP's strategy under uncertainties from wind power, load, market prices, and the requested power by the DSO. The model showed that the VPP involvement in distribution capacity contracts can improve its remuneration when certain types of Distributed Energy Resources (DER) are used to provide the service.

  • 1866. Alvarez Vergara, Davey
    Design, technical development and prototyping of products for sensory stimulations of mentally handicapped2008Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this project was to develop products or prototypes for sensory stimulation of individuals with mental disability. The objective is that with this products improve the overall functioning of persons with mental handicaps. A side objective was to create an illustrative guideline scheme to assist in the development of additional sensory products.The project was systematically executed using problem solving methods and with the support of the people that collaborated with information to the project. A substantial amount of background studies were made to obtain knowledge about mental disabilities, treatments and the functioning of the senses. The work can be summarized by four concepts designed with the intention to stimulation of the sense of hearing, touch and vision, and encourage the improvement of cognitive, communication and motor skills.One of the most important aspects in rehabilitation is, the rate of recurrence of the exercises, and to encourage the user to use the products,they were designed so they can be used both as an exercise tool and as a plaything. These solutions can give a child with disability a chance to continue the rehabilitation work at home, and to improve vital functions that are needed to obtain better possibilities to function independently in society.

  • 1867. Alvarez Villa, Ruben
    Mapping and analyses of the process for auto-rickshaw manufacturing2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Nowadays, many auto-rickshaws used in India are similar in design of the Piaggio Ape C from 1956, based on the Vespa. There are millions of people in need of a low priced and efficient means of transportation. A huge market for these auto-rickshaws exist in India because the population there is over 1,2 billion people. This thesis aims to continue the development of the vehicle platform for a new hybrid auto-rickshaw that is more environmentally friendly and better suited for its users. The goals for this hybrid auto-rickshaw are improving vehicle handling, impact safety, passenger and driver ergonomics. The thesis is focused in the analysis of the available manufacturing processes, in order to propose efficient and economical production methods for the monocoque chassis of the auto-rickshaw. The conceptual design of the hybrid auto-rickshaw has been improved due to the study and analysis of different manufacturing methods. The studies carried out shows which are the most feasible designs for production of each part.The revised structure of the chassis and the manufacturing techniques proposed are used to estimate the cost of the whole vehicle. The estimation of costs gives an idea of the final price of the vehicle, in order to evaluate the economical viability of this project.

  • 1868.
    Alvarez, Manuel
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Distribution Network Planning Considering Capacity Mechanisms and Flexibility2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The increasing penetration of distributed energy resources (DERs) has posed challenges to the distribution system operator (DSO) from the operation and regulatory point of view. High penetration of DERs could have negative impacts on the performance of the distribution grid, and depending on the regulatory framework, the DSO's remuneration as well. In liberalized electrical systems, the focus on promoting eciency has led to the implementation of an incentive-based regulation that exerts additional pressure on the DSOs to reduce costs. Additionally, the European Parliament Directive 2009/72/EC establishes a regulatory unbundling among the distribution, production, and retailing activities within the same vertically integrated electric utility.

    A way of helping the DSO to cope with the posed challenges is by providing it with exibility. This exibility can be acquired from the planning stage, and later be used during the system operation. This exibility can stem from the DSO's ability to exert control on the demand and the supply side to balance the system and correct its operational state.

    Based on the European DSOs' current situation at facing the increasing penetration of DERs, this thesis investigates in non-wired exible grid tools to solve the distribution network expansion problem. The investigation focuses on exibility providers, in particular on energy storage systems and hydropower, and also on capacity mechanisms to translate the capacity from DERs into the grid's capacity for planning purposes.

    Given that the share of renewable sources among the DERs is increasing, and considering the importance of energy storage systems in providing exibility to balance renewable energy production, the eort has been turned on to developing a hydropower model and a generic storage model that t both planning and operational studies.

    Given the need for gearing the DERs' behavior into the DSO's decision making process during the planning and operational timescales, the design and implementation of a distribution capacity mechanism have been developed. The design of the capacity mechanism has been conceived considering its integration within the distribution network expansion problem.

    The outcomes of this thesis can be synthesized as follows: 1) A generic hydraulic/storage model provided with an equivalent marginal cost that aids in considering the impact of present decisions in the future costs. 2) A market oriented distribution capacity mechanism that gears DERs and the DSOs to benefit mutually. 3) A distribution network expansion planning formulation that integrates the capacity resource from DERs through the distribution capacity mechanism.

  • 1869.
    Alvarez, Manuel
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Rönnberg, Sarah
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Bollen, Math
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Frías, Pablo
    Comillas Pontifical University, Madrid, Spain.
    Cossent, Rafael
    Comillas Pontifical University, Madrid, Spain.
    Jabr, Rabih
    American University of Beirut, Beirut, Lebanon.
    Zhong, Jin
    The University of Hong Kong, Hong Kong, China.
    A Capacity Mechanism Design for Distribution Network Expansion Planning2018In: 2018 IEEE International Conference on Environment and Electrical Engineering and 2018 IEEE Industrial and Commercial Power Systems Europe (EEEIC / I&CPS Europe), 2018, article id 8493874Conference paper (Refereed)
    Abstract [en]

    Capacity remuneration mechanisms have been originally oriented to ensure availability and continuity of supply on the power generation pool. Equivalent generation-based capacity mechanisms could be implemented to enhance and prolong the usability of the distribution grid. In particular, such capacity mechanisms would provide an alternative to traditional expansion options leading to investment deferral. In this work, a distribution capacity mechanism to fit within a distribution network planning methodology will be proposed and discussed. The capacity mechanism will be outlined following similar guidelines as for the design of capacity mechanisms used in the energy only market. The result of the design is a volume based capacity auction for a capacity-constrained system, oriented to both the active and the reactive power provision.

  • 1870. Alvarsdotter, Freja
    Customer loyalty: a multiple case study in the Swedish chemical commodity market2006Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The marketing of today is increasingly shifting towards customer orientation, customer understanding and synergistic relationships. This shift has given new possibilities for companies operating in commodity markets to differentiate them selves and no longer be completely dependent on price. The commodity companies can rise above their commodity markets and differentiate their commodity products. Customer loyalty is the factor that can make the relationship between two companies more stabile. A company has a unique advantage over the competitors if its customers want to stay with the company. The purpose of this thesis was to find out how the determinants and moderators of customer loyalty can be characterised and described in a commodity market. A multiple case study has been performed by interviewing four customers of a Swedish chemical commodity company. The factors describing and characterising customer perceived value, customer satisfaction and switching costs, all said to influence customer loyalty, and customer loyalty has been investigated. This study shows that the customer satisfaction perceived by the customers is influencing the customer loyalty. The customer satisfaction is in turn influenced by the customer value perceived. The switching costs only influence the satisfaction-loyalty linkage on this market if they are high.

  • 1871. Alveblom, Maria
    Hur tonåringar påverkas av att leva med acne: En systematisk litteraturöversikt2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 1872. Alvedro Buño, José Luis
    et al.
    Cabada Gutierrez, Beatriz
    Life cycle assessment of two parts of a crane: supporting member, crane member2010Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The purpose of this report is to compare the environmental impact of two alternative ways of manufacturing two different parts of a crane, for HIAB Company. To realize the study it is used the LCA. -The first part of the report is a detailed explanation of what is an LCA. An LCA is a systematic tool that enables the analysis of environmental loads of a product throughout its entire life cycle and the potential impacts of these loads on the environment. The essence of life cycle assessment is the identification, examination, and evaluation of the relevant environmental implications of a material, process, product, or system across its life span from creation to waste or, preferably, to re-creation in the same or another useful form. The LCA will provide the company a new environmental perspective on their manufacturing processes, and help it to choose the most effective process, identifying key environmental issues associated with both alternatives. -The second part is the LCA of the two different ways of manufacturing two different parts of a crane. There are several LCA software tools in the market, but the price of an LCA software tool can be around several thousand Euros and this is the reason that prevented us from carrying out the analysis with any LCA software, so the calculation are made with EXCEL. The studied products are the crane member and the supporting member, so actually are realized two different assessments, that are divided in assessment 1(crane member) and assessment 2 (supporting member). The new designs of both pieces are made with new higher strength steels, with better mechanical properties, therefore the dimensions and weight of the pieces will be reduced, but the company wants to know the environmental impact of them. These assessments are based on public available free resource, because it was impossible to get all the data from the company, so the results are not exactly, but the calculation are made with EXCEL, so is easy to obtain different results only changing the input parameters. After the assessment we can establish the following conclusions. Crane member: The new design is less environmentally friendly due to some elements of the new steel. Supporting member: Every phase analyzed in this study have a less environmental impact in the new design. -The last part of the report is a summary of different LCA software tools and shows an example of what can be done if you have access to an LCA software, the Simapro.

  • 1873.
    Alves, Mariana
    et al.
    Arkitektur- och designcentrum.
    Ehrnberger, Karin
    Kungliga tekniska högskolan, KTH.
    Jahnke, Marcus
    SP Sveriges Tekniska Forskningsinstitut.
    Wikberg-Nilsson, Åsa
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Innovation and Design.
    NOVA: Verktyg och metoder för normkreativ innovation2016Report (Other (popular science, discussion, etc.))
    Abstract [sv]

    Alla är sig själv närmast. Och vi gör oftast som vi är vana att göra. Vi styrs av de normer och värderingar som har format oss - även om vi tror att vi är innovativa. Resultatet riskerar att bli lösningar som diskriminerar och begränsar. En stor utmaning är att förstå andra människors behov. Om vi kan använda ett normkritiskt perspektiv och se bortom våra egna ramar kan vi nå en större potential inom innovation. Men att förverkliga den potentialen är lättare sagt än gjort. Det krävs vad vi kallar normkreativitet. Normkreativitet bygger på en medvetenhet om att normer och värderingar kan begränsa och diskriminera. Men den kräver också ett analytiskt arbete att undersöka människors verkliga situation och djupliggande behov - och samtidigt ett kreativt arbete att omsätta kritik och kunskap i nya lösningar. NOVA innehåller konkreta verktyg och handfasta metoder för alla som vill skapa sådana normkreativa lösningar. Materialet är baserat på praktiskt erfarenhet och forskning från en mängd olika projekt och studier. Formatet är valt för att gynna kreativitet och samverkan. Fokus är på normer som diskriminerar, men egentligen är innehållet användbart i alla innovationssammanhang. All innovation handlar ju om att utmana normer.

  • 1874.
    Alveteg, Ellen
    Luleå University of Technology, Department of Arts, Communication and Education.
    Dra stråken till sin spets: En undersökning av extended techniques för viola genom instudering av Viola Spaces av Garth Knox2018Independent thesis Basic level (degree of Bachelor of Fine Arts), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Efter att ha gått en kurs i fri improvisation där jag fick utforska min violas möjligheter till att producera ljud, väcktes en nyfikenhet hos mig kring utökade speltekniker som kan förekomma i nutida konstmusik, så kallade extended techniques. Jag fick tips om etydsamlingen Viola Spaces av Garth Knox där olika extended techniques presenteras och bestämde mig för att studera in fyra av dem. De etyderna jag valde behandlar olika stråktekniker, nämligen sul ponticello, sul tasto, tremolo och olika sätt att dra stråken på.

    Under arbetets gång redogör jag för de svårigheter jag stötte på under min inlärningsprocess av etyderna samt hur jag gick till väga för att lösa dem. Arbetet redovisas dels genom videoinspelningar som jag gjorde i samband med mina övningstillfällen och dels genom material från de anteckningar jag förde under processen. Jag tar också upp tolkningsfrågor av notationen och reflekterar kring instruktionerna om hur musiken ska framföras.

    Arbetet har resulterat i att jag känner mig bättre förberedd på att spela nutida konstmusik än vad jag gjorde tidigare. Jag har också utökat min kunskap om olika stråktekniker.

     

  • 1875.
    Alvi, Sajid
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Akhtar, Farid
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    High temperature tribology of polymer derived ceramic composite coatings2018In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 15105Article in journal (Refereed)
    Abstract [en]

    Polymer derived ceramic (PDC) composite coatings were deposited on AISI 304 substrates using siloxane based preceramic polymer polymethlysilsquioxane (PMS) and ZrSi2 as active filler or Ag as passive filler. The tribological performance of the composite coatings was evaluated at room temperature and moderately high temperatures (150 °C, 200 °C, 300 °C and 400 °C). The composite coatings showed low coefficient of friction (COF), µ, from 0.08 to 0.2 for SiOC-ZrSi2 composite coatings, and from 0.02 to 0.3 for SiOC-Ag composite coatings, at room temperature with increasing normal load from 1 to 5 N. High temperature tribology tests showed high COF values from 0.4 to 1 but low wear for SiOC-ZrSi2 coating, and low COF from 0.2 to 0.3 for SiOC-Ag coatings at lower temperature ranges. Low load friction tests at room temperature showed negligible wear in SiOC-ZrSi2 coatings, suggesting good wear resistant and lubricating properties due to formation of t-ZrO2 and carbon. Low COF and high amount of wear was observed in SiOC-Ag composite coatings at room temperature due to high ductility of Ag and smearing of wear debris in the wear track. The coatings and wear tracks were characterized to evaluate the lubrication and wear behavior.

  • 1876.
    Alvi, Sajid
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Akhtar, Farid
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    High temperature tribology of CuMoTaWV high entropy alloy2019In: Wear of Materials, 2019, Vol. 426-427, p. 412-419Conference paper (Refereed)
    Abstract [en]

    An equiatomic high entropy alloy (HEA) CuMoTaWV was designed for room temperature to high temperature wear applications using spark plasma sintering of elemental powder mixture at 1400 °C. The sintered solid solution showed uniform distribution of elements in a BCC high entropy alloy phase along with V rich solid solution phase with an average hardness of 600 Hv and 900 Hv, respectively. Room temperature (RT) dry sliding wear tests, against alloy steel (700–880 Hv) for 200 m sliding distance at 5 N normal load, showed negligible wear of 5 × 10−7 mm/N m and a coefficient of friction (COF) of 0.5. Sliding wear characterization of sintered CuMoTaWV alloy against Si3N4 (1550 Hv) counter body from RT to 600 °C showed an increasing average COF of 0.45–0.67 from RT to 400 °C and then reducing to 0.54 at 600 °C. The wear rate was found to be lower at RT (4 × 10−3 mm3/N m) and 400 °C (5 × 10−3 mm3/N m), and slightly higher at 200 °C (2.3 × 10−2 mm3/N m) and 600 °C (4.5 × 10−2 mm3/N m). The CuMoTaWV alloy showed wear mechanisms specific to the test temperatures. The wear of CuMoTaWV alloy was governed by adhesive wear at RT and 200 °C and oxidative wear at 400 °C and 600 °C. The analyses of wear surfaces showed that the low wear rate at RT was due to the high hardness of the HEA, presence of V rich zones and formation of W and Ta tribofilm. At 400 °C, the formation of CuO tribolayer reduced the wear and hindered oxidation of wear track. At 600 °C, the wear rate increased due to oxidation of Cu, Ta and W. Moreover, the formation of lubricating elongated magneli phase V2O5 in V rich regions of CuMoTaWV alloy reduced the COF to 0.54.

  • 1877.
    Alzghoul, Ahmad
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Improving availability of industrial products through data stream mining2011Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Products of high quality are of great interest for industrial companies. The quality of a product can be considered in terms of production cost, operating cost, safety and product availability, for example. Product availability is a function of maintainability and reliability. Monitoring prevents unplanned stops, thus increasing product availability by decreasing needed maintenance. Through monitoring, failures can be detected and/or avoided. Detecting failures eliminates extra costs such as costs associated with machinery damage and dissatisfied customers, and time is saved since stops can be scheduled, instead of having unplanned stops. Product monitoring can be done through searching the data generated from sensors installed on products.Nowadays, the data can be collected at high rates as part of a data stream. Therefore, data stream management systems (DSMS) and data stream mining (DSM) are being used to control, manage and search the data stream. This work investigated how the availability of industrial products can be increased through the use of DSM and DSMS technologies.A review of the data stream mining algorithms and their applications in monitoring was conducted. Based on the review, a new data stream classification method, i.e. Grid-based classifier was proposed, tested and validated. Also, a fault detection system based on DSM and DSMS technologies was proposed. The proposed fault detection system was tested using data collected from Hägglunds Drives AB (HDAB) hydraulic motors. Thereafter, a data stream predictor was integrated into the proposed fault detection system to detect failures earlier, thus gaining more time for response actions. The modified fault detection system was tested and showed good performance. The results showed that the proposed fault detection system, which is based on DSM and DSMS technologies, achieved good performance (with classification accuracy around 95%) in detecting failures on time. Detecting failures on time prevents unplanned stops and may improve the maintainability of the industrial systems and, thus, their availability.

  • 1878.
    Alzghoul, Ahmad
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Mining data streams to increase ‎industrial product availability2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Improving product quality is always of industrial interest. Product availability, a function of product maintainability and reliability, is an example of a measurement that can be used to evaluate product quality. Product availability and cost are two units which are especially important to manage in the context of the manufacturing industry, especially where industry is interested in selling or buying offers with increased service content. Industry in general uses different strategies for increasing equipment availability; these include: corrective (immediate or delayed) and preventive strategies. Preventive strategies may be further subdivided into scheduled and predictive (condition-based) maintenance strategies. In turn, predictive maintenance may also be subdivided into scheduled inspection and continuously monitored. The predictive approach can be achieved by early fault detection. Fault detection and diagnosis methods can be classified into three categories: data-driven, analytically based, and knowledge-based methods. In this thesis, the focus is mainly on fault detection and on data-driven models.Furthermore, industry is generating an ever-increasing amount of data, which may eventually become impractical to store and search, and when the data rate is increasing, eventually impossible to store. The ever-increasing amount of data has prompted both industry and researchers to find systems and tools which can control the data on the fly, as close to real-time as possible, without the need to store the data itself. Approaches and tools such as Data Stream Mining (DSM) and Data Stream Management Systems (DSMS) become important. For the work reported in this thesis, DSMS and DSM have been used to control, manage and search data streams, with the purpose of supporting increased availability of industrial products.Bosch Rexroth Mellansel AB (formerly Hägglunds Drives AB) has been the industrial partner company during the course of the work reported in this thesis. Related data collection concerning the functionality of the BRMAB hydraulic system has been performed in collaboration with other researchers in Computer Aided Design at Luleå University of Technology.The research reported in this thesis started with a review of data stream mining algorithms and their applications in monitoring. Based on the review, a data stream classification method, i.e. Grid-based classifier, was proposed, tested and validated (Paper A). Also, a fault detection system based on DSM and DSMS was proposed and tested, as reported in Paper A. Thereafter, a data stream predictor was integrated into the proposed fault detection system to detect failures earlier, thus demonstrating how data stream prediction can be used to gain more time for proactive response actions by industry (Paper B). Further development included an automatic update method which allows the proposed fault detection system to be able to overcome the problem of concept drift (Paper E). The proposed and modified fault detection systems were tested and verified using data collected in collaboration with Bosch Rexroth Mellansel AB (BRMAB). The requirements for the proposed fault detection system and how it can be used in product development and design of the support system were also discussed (Paper C). In addition, the performance of a knowledge-based method and a data- driven method for detecting failures in high-volume data streams from industrial equipment have been compared (Paper D). It was found that both methods were able to detect all faults without any false alert. Finally, the possible implications of using cloud services for supporting industrial availability are discussed in Paper F. Further discussions regarding the research process and the relations between the appended papers can be found in Chapter 2, Figure 4 and in Chapter 5, Figure 21.The results showed that the proposed and modified fault detection systems achieved good performance in detecting and predicting failures on time (see Paper A and Paper B). In Paper C, it is shown how data stream management systems may be used to increase product availability awareness. Also, both the data-driven method and the knowledgebased method were suitable for searching data streams (see Paper D). Paper E shows how the challenge of concept drift, i.e. the situation in which the statistical properties of a data stream change over time, was turned to an advantage, since the authors were able to develop a method to automatically update the safe operation limits of the one-class data-driven models.In general, detecting faults and failures on time prevents unplanned stops and may improve both maintainability and reliability of industrial systems and, thus, their availability (since availability is a function of maintainability and reliability). By the results, this thesis demonstrates how DSM and DSMS technologies can be used to increase product availability and thereby increase product quality in terms of availability.

  • 1879. Alzghoul, Ahmad
    et al.
    Backe, Björn
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Löfstrand, Magnus
    Uppsala universitet.
    Byström, Arne
    Uppsala University, Department of Information Technology, Division of Computing Science.
    Liljedahl, Bengt
    Bosch Rexroth Mellansel AB.
    Comparing a knowledge-based and a data-driven method in querying data streams for system fault detection: A hydraulic drive system application2014In: Computers in industry (Print), ISSN 0166-3615, E-ISSN 1872-6194, Vol. 65, no 8, p. 1126-1135Article in journal (Refereed)
    Abstract [en]

    The field of fault detection and diagnosis has been the subject of considerable interest in industry. Fault detection may increase the availability of products, thereby improving their quality. Fault detection and diagnosis methods can be classified in three categories: data-driven, analytically based, and knowledge-based methods. In this work, we investigated the ability and the performance of applying two fault detection methods to query data streams produced from hydraulic drive systems. A knowledge-based method was compared to a data-driven method. A fault detection system based on a data stream management system (DSMS) was developed in order to test and compare the two methods using data from real hydraulic drive systems. The knowledge-based method was based on causal models (fault trees), and principal component analysis (PCA) was used to build the data-driven model. The performance of the methods in terms of accuracy and speed, was examined using normal and physically simulated fault data. The results show that both methods generate queries fast enough to query the data streams online, with a similar level of fault detection accuracy. The industrial applications of both methods include monitoring of individual industrial mechanical systems as well as fleets of such systems. One can conclude that both methods may be used to increase industrial system availability

  • 1880.
    Alzghoul, Ahmad
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Löfstrand, Magnus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Increasing availability of industrial systems through data stream mining2011In: Computers & industrial engineering, ISSN 0360-8352, E-ISSN 1879-0550, Vol. 60, no 2, p. 195-205Article in journal (Refereed)
    Abstract [en]

    Improving industrial product reliability, maintainability and thus availability is a challenging task for many industrial companies. In industry, there is a growing need to process data in real time, since the generated data volume exceeds the available storage capacity. This paper consists of a review of data stream mining and data stream management systems aimed at improving product availability. Further, a newly developed and validated grid-based classifier method is presented and compared to one-class support vector machine (OCSVM) and a polygon-based classifier.The results showed that, using 10% of the total data set to train the algorithm, all three methods achieved good (>95% correct) overall classification accuracy. In addition, all three methods can be applied on both offline and online data.The speed of the resultant function from the OCSVM method was, not surprisingly, higher than the other two methods, but in industrial applications the OCSVMs' comparatively long time needed for training is a possible challenge. The main advantage of the grid-based classification method is that it allows for calculation of the probability (%) that a data point belongs to a specific class, and the method can be easily modified to be incremental.The high classification accuracy can be utilized to detect the failures at an early stage, thereby increasing the reliability and thus the availability of the product (since availability is a function of maintainability and reliability). In addition, the consequences of equipment failures in terms of time and cost can be mitigated.

  • 1881.
    Alzghoul, Ahmad
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Löfstrand, Magnus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Backe, Björn
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Data stream forecasting for system fault prediction2012In: Computers & industrial engineering, ISSN 0360-8352, E-ISSN 1879-0550, Vol. 62, no 4, p. 972-978Article in journal (Refereed)
    Abstract [en]

    Competition among today’s industrial companies is very high. Therefore, system availability plays an important role and is a critical point for most companies. Detecting failures at an early stage or foreseeing them before they occur is crucial for machinery availability. Data analysis is the most common method for machine health condition monitoring. In this paper we propose a fault-detection system based on data stream prediction, data stream mining, and data stream management system (DSMS). Companies that are able to predict and avoid the occurrence of failures have an advantage over their competitors. The literature has shown that data prediction can also reduce the consumption of communication resources in distributed data stream processing.In this paper different data-stream-based linear regression prediction methods have been tested and compared within a newly developed fault detection system. Based on the fault detection system, three DSM algorithms outputs are compared to each other and to real data. The three applied and evaluated data stream mining algorithms were: Grid-based classifier, polygon-based method, and one-class support vector machines (OCSVM).The results showed that the linear regression method generally achieved good performance in predicting short-term data. (The best achieved performance was with a Mean Absolute Error (MAE) around 0.4, representing prediction accuracy of 87.5%). Not surprisingly, results showed that the classification accuracy was reduced when using the predicted data. However, the fault-detection system was able to attain an acceptable performance of around 89% classification accuracy when using predicted data.

  • 1882.
    Alzghoul, Ahmad
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Löfstrand, Magnus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Karlsson, Lennart
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Karlberg, Magnus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Data stream mining for increased functional product availability awareness2011In: Functional Thinking for Value Creation: Proceedings of the 3rd CIRP International Conference on Industrial Product Service Systems, Technische Universität Braunschweig, Braunschweig, Germany, May 5th - 6th, 2011 / [ed] Jürgen Hesselbach; Christoph Herrmann, Berlin: Encyclopedia of Global Archaeology/Springer Verlag, 2011, p. 237-241Conference paper (Refereed)
    Abstract [en]

    Functional Products (FP) and Product Service Systems (PSS) may be seen as integrated systems comprising hardware and support services. For such offerings, availability is key. Little research has been done on integrating Data Stream Management Systems (DSMS) for monitoring (parts of) a FP to improve system availability. This paper introduces an approach for how data stream mining may be applied to monitor hardware being part of a Functional Product. The result shows that DSMS have the potential to significantly support continuous availability awareness of industrial systems, especially important when the supplier is to supply a function with certain availability.

  • 1883.
    Al-Zubaidi, Ibrahim
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Numerisk simulering av sättningar och portryck för en provbank på sulfidjord2017Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Den finkorniga sulfidjorden som finns längs Norrlandskusten är känd för sin stora sättningsbenägenhet och utgör en potentiell miljörisk genom försurning och urlakning av metaller om den inte hanteras rätt. För att förebygga miljörisker och utveckla jordförstärknings- och grundläggningsmetoder måste en ökad kunskap om sulfidjordar tas fram. I ett pågående forskningsprojekt vid Statens Geotekniska Institut studeras sulfidjords kompressionsegenskaper och rekommendationer ska tas fram avseende underlag för sättningsberäkningar. I projektet omfattas ett antal provbankar där ett av dessa områden, Lampen ligger i Kalix i norra Sverige. I detta examensarbete har det utförts numeriska analyser i finita elementprogrammet PLAXIS 2D av sättningar och portryck under en av provbankarna i Lampen och jämförelser görs med tidigare rapporterade fältmätningar.

    Tre olika delar analyseras i FE-programmet PLAXIS 2D. I den första delen, som är huvuddelen, utvärderas materialmodellernas, Soft Soil (SS) respektive Soft Soil Creep (SSC), förmåga att simulera de uppmätta sättningarna och porövertrycken för en period av cirka ett års belastning av provbank. Den andra delen består av en analys av de två deformationstillstånden, axialsymmetriskt och plant. De två deformationstillståden jämförs med hänsyn till sättningar och portryck. I den tredje delen utvärderas påverkan på simulerade resultat av olika nivåer på grundvattenytan, en variation som har observerats i provområdet i Lampen.

    Vid en jämförelse av de konstitutiva modellerna noteras som förväntat större sättningar vid användning av SSC-modellen i jämförelse med SS-modellen. SSC-modellen visar även ett högre porövertryck. Vid jämförelse med i fält uppmätta värden noteras att de mest överensstämmande sättningarna erhålls från SS-modellen medan portrycksutvecklingen simuleras bättre, men ändå långt från bra, med SSC-modellen (för simulering med dubbelsidig dränering).

    Vid analys av deformationstillstånd (axialsymmetriskt kontra plant) noteras en jämnare fördelning av deformationer längs banken vid användandet av axialsymmetriskt tillstånd. Den potentiella brottrörelsen som uppvisas vid släntkrön vid tillämpning av plant deformationstillstånd är inte lika tydlig vid axialsymmetriskt tillstånd. Det axialsymmetriska tillståndet visar även ett lägre porövertryck.

    Numeriska simuleringar av den varierande nivån på grundvattenytan som observerats i fältmätningar visar vid fallet en lägre antagen grundvattennivå en marginellt mindre sättning.  Potentiella brottrörelser blir inte lika tydliga då den lägre nivån på grundvattenytan simuleras.

  • 1884.
    Al-Zubaydi, Jaffar
    et al.
    Applied Geology Department, College of Science, University of Babylon.
    Alabidi, Abdulkadhim
    Department of Geology, Faculty of Science, University of Kufa.
    Al-Janabi, Ali
    Applied Geology Department, College of Science, University of Babylon.
    Al-Ansari, Nadhir
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Engineering and Tectonic Study of Rocks Discontinuities in the Proposed Abo-Hederya Quarry Site, Missan SE Iraq2016In: Engineering, ISSN 1947-3931, E-ISSN 1947-394X, Vol. 8, no 8, p. 525-534Article in journal (Refereed)
    Abstract [en]

    A detailed field survey of discontinuity (fractures) was carried out in the proposed Abo-Hederya Quarry Site, 70 km east Missan city, south-east of Iraq, where Al-Mukdadiya Formation (Upper Miocene-Pliocene) is exposed. The discontinuity survey was carried out in 10 stations covering the study area. At each station notes were collected about beds (lithology, thickness and orientation) and discontinuities (orientation, density, spacing, persistence and aperture). The slope stability analysis suggests that there is no real hazard area that could affect the quarry in future. Tectonic analysis demonstrates that tension fractures are common in the study area, while shear fractures (okl, hko, hol and hkl) are the less. The maximum principal stress direction in the study area is N (15 - 40) E, which is compatible with the regional tectonic stress in the area.

  • 1885.
    Al-Zuheri, Atiya
    et al.
    Ministry of Science and Technology, Baghdad, Iraq.
    Rashad, Haider
    Ministry of Science and Technology, Baghdad, Iraq.
    Al-Maliki, Ali A.
    Ministry of Science and Technology, Baghdad, Iraq.
    Hussain, Hassain M.
    Remote Sensing Center, University of Kufa, Najaf, Iraq.
    Al-Ansari, Nadhir
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Determination of the chemical Structure of the Iraqi Oil Shale and its hydrocarbon Forms2018In: Engineering, ISSN 1947-3931, E-ISSN 1947-394X, Vol. 10, no 1, p. 7-20Article in journal (Refereed)
    Abstract [en]

    The global impact of shale oil has revolutionized the world’s energy markets, resulting in significantly lower oil prices, higher global gross domestic product, changing geopolitics and shifted business models for oil and gas companies. Further and developed research initiative is required to fill critical gaps in knowledge at the interface of shale oil development along with environmental protection, so countries can prepare better for its energy future. This paper explores the characterization of Iraqi originated oil shale using various analytical techniques, such as mass spectrometry (MS), infrared spectroscopy (IR), and Gas Chromatography Mass Spectrography (GC/MS). Based upon analytical results, it is found that the majority of chemical structure is in aliphatic hydrocarbon forms.

  • 1886. Alzén, Peter
    Multi-cell Performance of IEEE 802.11a Wireless LANs2004Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Wireless data networks is a growing business and the demand for higher capacity is increasing rapidly. There exist a number of standards for wireless LANs (WLANs) and the most popular one is the IEEE 802.11 family. This thesis investigates the capacity of IEEE 802.11a for a multi-cell environment. The use of many access points (APs) results in a need to reuse the available channels, IEEE 802.11a has 12. A higher reuse factor corresponds to less channels in each AP but larger co-channel distances, hence less interference. There exists an “optimal” cell radius for each reuse, where the capacity per cell and channel is maximized. The total capacity per area unit can be increased by adding more APs, at the cost of decreased utilization of each AP. When two co-channel cells get close enough, they time-share the medium instead of using it separately.

  • 1887. Aläng, Stefan
    et al.
    Stenvall, Joakim
    Vibreringsfri stålfiberarmerad betong: utvärderade materialegenskaper tillämpade på plattor1999Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 1888. Amadei, Bernard
    et al.
    Stephansson, Ove
    Luleå tekniska universitet.
    Rock stress and its measurements1997 (ed. 1)Book (Other academic)
  • 1889.
    Amadeo, Marcia
    et al.
    Universita Mediterranea di Reggio Calabria.
    Campolo, Claudia
    Universita Mediterranea di Reggio Calabria. Telecommunications.
    Quevedo, Jose
    Universidade de Aveiro, Inst Telecomunicacoes.
    Corujo, Daniel
    Universidade de Aveiro, Inst Telecomunicacoes.
    Molinaro, Antonella
    Universita Mediterranea di Reggio Calabria. Telecommunications.
    Iera, Antonio
    Universita Mediterranea di Reggio Calabria.
    Aguiar, Rui L.
    Universidade de Aveiro, Inst Telecomunicacoes.
    Vasilakos, Athanasios
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Information-Centric Networking for the Internet of Things: Challenges and Opportunities2016In: IEEE Network, ISSN 0890-8044, E-ISSN 1558-156X, Vol. 30, no 2, p. 92-100, article id 7437030Article in journal (Refereed)
    Abstract [en]

    In view of evolving the Internet infrastructure, ICN is promoting a communication model that is fundamentally different from the traditional IP address-centric model. The ICN approach consists of the retrieval of content by (unique) names, regardless of origin server location (i.e., IP address), application, and distribution channel, thus enabling in-network caching/replication and content-based security. The expected benefits in terms of improved data dissemination efficiency and robustness in challenging communication scenarios indicate the high potential of ICN as an innovative networking paradigm in the IoT domain. IoT is a challenging environment, mainly due to the high number of heterogeneous and potentially constrained networked devices, and unique and heavy traffic patterns. The application of ICN principles in such a context opens new opportunities, while requiring careful design choices. This article critically discusses potential ways toward this goal by surveying the current literature after presenting several possible motivations for the introduction of ICN in the context of IoT. Major challenges and opportunities are also highlighted, serving as guidelines for progress beyond the state of the art in this timely and increasingly relevant topic.

  • 1890.
    Amakawa, Hiroshi
    et al.
    University of Tokyo.
    Ingri, Johan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Masuda, Akimasa
    University of Tokyo.
    Shimizu, Hiroshi
    University of Tokyo.
    Isotopic compositions of Ce, Nd and Sr in ferromanganese nodules from the Pacific and Atlantic Oceans, the Baltic and Barents Seas, and the Gulf of Bothnia1991In: Earth and Planetary Science Letters, ISSN 0012-821X, E-ISSN 1385-013X, Vol. 105, no 4, p. 554-565Article in journal (Refereed)
    Abstract [en]

    Ferromanganese nodules from the Pacific and Atlantic Oceans, the Barents and Baltic Seas, and the Gulf of Bothnia were analyzed for the isotopic compositions of Ce, Nd and Sr and the abundances of REE, Ba and Sr. REE patterns of Barents, Baltic and Bothnian samples show no Ce anomaly, or even a negative one, in contrast to the positive anomaly observed for the Pacific and Atlantic samples. Moreover, the Baltic and Bothnian samples have distinctly low εNd values; average εNd values of the four regions are as follows: Pacific -5, Barents -10, Atlantic -11 and Baltic inclusive of Gulf of Bothnia -19. The characteristic low εNd values of the Baltic samples are indicative of the influence of Precambrian rocks from the Baltic shield. Of particular interest is the feature of the Ce isotopic composition that εCe values of the samples from the Pacific are negative and those from the other three regions positive. This novel finding might suggest a difference in sources of Ce between the Pacific and other regions. These results demonstrate that Ce isotopic ratios can be a useful tracer in marine geochemistry, in combination with isotopic compositions of Nd and Sr.

  • 1891. Amakawa, Hiroshi
    et al.
    Ingri, Johan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Masuda, Akimasa
    Shimizu, Hiroshi
    Isotopic compositions of Ce, Nd and Sr in ferromanganese nodules from various oceanic regions1992In: Abstracts : 29th International Geological Congress, Kyoto, Japan, 24 August - 3 September 1992, 1992, p. 613-Conference paper (Other academic)
  • 1892. Amankwah, Susana
    et al.
    Ohene-Adu, William
    Assessment and Analysis of Service Quality and Customer Satisfaction: A Case Study of National Investment Bank, Kumasi2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In this era of intense competition, one of the key challenges that organisations face is how to manage quality service which is a prerequisite for customer satisfaction. As a result of improved information communication technology, customers have become well informed, discerning and value sensitive. They also have a wide range of choices between service providers. Understanding the need, wants and desires of customers and demonstrated ability to satisfy them efficiently is imperative for success in the market place. The purpose of this research is to assess and analyse service quality and customer satisfaction with banking services at National Investment Bank, Kumasi. Based on detailed literature review of business journals and books, a frame of reference was developed. Five generic service quality dimensions (tangibles, empathy, assurance responsiveness and reliability) were selected and tested in NIB Kumasi operations. A qualitative research approach was used in the study. Data was collected through questionnaire and interview. Data presentation and analysis were done in the accordance with the research questions and the frame of reference. Finally, in the last chapter, findings and conclusions were drawn with the appropriate recommendations. The quality performance of all tested quality dimensions proved to have a strong impact on customer satisfaction. However, tangibles, empathy and assurance were found to be of much significance to customers of NIB Kumasi. Prestige banking and expansion of service portfolio to include more electronic banking products were the new service needs identified in our research.

  • 1893.
    Amara, S.
    et al.
    Unité de Recherche en Energies Renouvelables en Milieu Saharien (URER/MS).
    Benyoucef, B.
    Unité de Recherche Matériaux et Energies Renouvelables (URMER), Université de Tlemcen.
    Nordell, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Touzi, A.
    Unité de Recherche en Energies Renouvelables en Milieu Saharien (URER/MS).
    Benmoussat, A.
    Unité de Recherche Matériaux et Energies Renouvelables (URMER), Université de Tlemcen.
    Experimental study of a concentration heating system with optical fiber supply2009In: Abstract book and proceedings : Effstock 2009: 11th International conference on Thermal Energy Storage for Energy Efficiency and Sustainability / [ed] Signhild Gehlin, Stockholm: Energi- och Miljötekniska Föreningen / EMTF Förlag , 2009Conference paper (Refereed)
    Abstract [en]

    The buildings thermal function is important to provide comfort to its tenants. This means to provide cooling during hot seasons and/or heating in cold season. Current study concerns modelling of a new design of thermal photo sensors that results in a more efficient heating for Tlemcen site, Algeria.

  • 1894.
    Amara, S.
    et al.
    Unité de Recherche en Energies Renouvelables en Milieu Saharien (URER/MS).
    Benyoucef, B.
    Unité de Recherche Matériaux et Energies Renouvelables (URMER), Université de Tlemcen.
    Nordell, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Touzi, A.
    Unité de Recherche Matériaux et Energies Renouvelables (URMER).
    Benmoussat, A.
    Unité de Recherche Matériaux et Energies Renouvelables (URMER), Université de Tlemcen.
    Experimental study of a domestic hot water storage tank thermal behaviour2009In: Abstract book and proceedings : Effstock 2009: 11th International conference on Thermal Energy Storage for Energy Efficiency and Sustainability / [ed] Signhild Gehlin, Stockhiolm: Energi- och Miljötekniska Föreningen / EMTF Förlag , 2009Conference paper (Refereed)
    Abstract [en]

    Much work has been carried out on hot water storage during the last 20-30 years, particularly on solar heat applications. Theoretical and experimental studies on the internal heat transfer have been made at laboratory scale and at larger scales. Current study, which was conducted in order to understand the stratification phenomena, involved an experimental study on the thermal behaviour in a hot water tank during charging and discharging for domestic hot water storage. Results showed no effect of stratification due to the injection fluid from the bottom of the tank and the effect of mixed convection induced by the temperature difference which created a mixture inside the tank, where the temperature was uniform across the height, and the apparition of stratification due to the fact of discharge from the bottom of the tank.

  • 1895.
    Amara, Saidi
    et al.
    Unité de Recherche Matériaux et Energies Renouvelables (URMER), Université de Tlemcen.
    Baghdadli, T.
    Unité de Recherche Matériaux et Energies Renouvelables (URMER), Université de Tlemcen.
    Nordell, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Khimulu, R.
    Unité de Recherche Matériaux et Energies Renouvelables (URMER), Université de Tlemcen.
    Solar System Design for Water Treatment: Antibacterial Heat Exchanger (ABHE)2017In: Innovative Healthcare Systems for the 21st Century / [ed] Hassan Qudrat-Ullah, Peter Tsasis, Springer International Publishing , 2017, p. 167-180Chapter in book (Refereed)
    Abstract [en]

    Current study concerns the fundamental problems to eliminate pathogens that are responsible for waterborne diseases. These illnesses, which have followed man throughout history, are described by occurring symptoms such as diarrhea and nausea. The various organisms identified within this document as waterborne bacterial pathogens are, e.g., Legionella (causes Pontiac fever), Salmonella (typhoid fever), and Yersinia (plague). Several control methods are available for water disinfection: biocide, ultraviolet light sterilization, copper–silver ionization, ozonation, etc., but only thermal treatment can eliminate bacterial pathogens, which are killed almost instantly at 70 °C. The current chapter describes water disinfection by a solar concentrator combined with a heat recovery system that reduces the heat demand. Though this study is made for a small system (160 l of hot water per day), the system can be enlarged (more hot water and more solar collector area), and the results are thus valid also for such larger systems. Here experiments of water treatment by a solar concentrator are summarized and analyzed where the temperature exceeds 80 °C at the outlet of the heat exchanger.

  • 1896.
    Amara, Sofiane
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Corrigendum to “Using Fouggara for Heating and Cooling Buildings in Sahara” (Energy Procedia 6 (2011), 55–64)2011In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 6, p. 825-Article in journal (Refereed)
  • 1897.
    Amara, Sofiane
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Novel and ancient technologies for heating and cooling buildings2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The basic issue of this thesis concerns one of the fundamental problems of the future of our society: How to meet the energy requirements for a large and growing world population while preserving our environment? This question is important for the world and the answers are complex and interwoven.Conventional energy sources, fossil and fissile, are polluting in the present and in the future: they erode the environment and their resources are limited. Renewable energy (hydro, wind, solar, geothermal) constitutes a minimum of pollution in the different energy systems. The technologies for using renewable energy are well known though further development and progress are made. This development also requires behavioural change, adaptation, and above all political will. The transition from an economy based on fossil energy to an economy based on renewable energy appears necessary for the protection of the environment. The cost of renewable energy is often represented as an obstacle but remains competitive in the long run.The development and availability of renewable energy, which varies because of its spatial and temporal distribution, require an adaptation of lifestyle, habits, habitat design (passive bioclimatic houses), urban planning and transportation.The focus of this thesis was to apply renewable energy in an area with hot summers and cold winter, a climate like that in the northwest of Algeria. In order to provide improved comfort in the buildings and also economic development in this area, the energy demand for heating and cooling was analyzed in the ancient city of Tlemcen. To supply domestic hot water and space heating, water must be simultaneously available at two different temperature levels. Cold water temperature, close to that of the atmosphere, and hot water between 50 and 60°C. An interesting feature of the preparation of hot water is the small variation of requirements during the year, unlike that to heating. The preparation of hot water is one of the preferred applications of solar energy in the building for several reasons. For this reason an experimental study of the thermal behaviour of a domestic hot water storage tank was undertaken. The phenomena that affect the thermal behaviour of tank especially the coupling between the solar collector and storage tank was studied. This study included concentrating solar collector in which optical fibers were used to transport the energy to the storage tank. Another technology was introduced and developed for the heating and cooling of buildings in the desert involving an existing ancient irrigation system called Fouggara. The novel idea is to use the Fouggara as an air conditioner by pumping ambient air through this underground system. Then air at a temperature of about 21°C would be supplied to the building for heating in the winter and cooling in the summer. This study shows the feasibility of using this ancient irrigation system of Fouggara and contributes to reducing and eliminating the energy demand for heating and cooling buildings in the Sahara desert.

  • 1898.
    Amara, Sofiane
    et al.
    Université de Tlemcen, BP 119 Tlemcen.
    Baghdadli, Tewfik
    Université de Tlemcen, BP 119 Tlemcen.
    Knapp, Samuel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Nordell, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Legionella Disinfection by Solar Concentrator System2017In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 70, p. 786-792Article in journal (Refereed)
    Abstract [en]

    The current study concerns the fundamental problems of Legionnaires disease. Four decades after Legionnaires' bacteria was first identified there is still a low level of clinical awareness. Humans are infected by inhalation of aerosolized water and/or soil contaminated with the bacteria. Several control methods are available for water disinfection: biocide, ultraviolet light sterilization, copper-silver ionization, ozonation etc. but only thermal treatment can completely eliminate Legionella, which is killed almost instantly at 70 °C. The current paper describes Legionella disinfection by a solar concentrator combined with a heat recovery system that reduces the heat demand. Though this study is made for a small system (160 l of hot water per day) the system can be enlarged (more hot water and more solar collector area) and the results are thus valid also for such larger systems. Here experiments of water treatment by a solar concentrator are summarized and analyzed where the temperature exceeds 80 °C at the outlet of the heat exchanger.

  • 1899.
    Amara, Sofiane
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Benmoussat, A.
    Renewable Energy Research Unity in Saharien Middle, ‘URER/MS’.
    Benyoucef, B.
    Renewable Energy & Materials Research Unity, ‘URMER’.
    Nordell, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Requirements energy estimate of heating & cooling for a dwelling in the site of Tlemcen2007Article in journal (Refereed)
  • 1900. Amara, Sofiane
    et al.
    Benyoucef, Boumedielne
    Unité de Recherche Matériaux et Energies Renouvelables (URMER).
    Benhamou, M.
    Unité de Recherche en Energies Renouvelables en Milieu Saharien.
    Monougar, H.
    Unité de Recherche en Energies Renouvelables en Milieu Saharien.
    Touzi, A.
    Unité de Recherche en Energies Renouvelables en Milieu Saharien (URER/MS).
    Experimental study of a domestic hot water storage tank thermal behaviour: Etude experimentale du comportement thermique d'une cuve de stockage d'eau chaude sanitaire2009In: Physical & Chemical News, ISSN 1114-3800, Vol. 46, no Mars, p. 15-20Article in journal (Refereed)
    Abstract [en]

    Many works were carried out on heat storage during the 20-30 last years, particularly on solar heat storage applications. Theoretical and experimental studies on internal behaviour storage were made and carried as well on laboratory installations as on a large scale. In order to understand the stratification phenomena, an experimental study of tank thermal behaviour of charge and discharge of domestic heat water storage is undertaken.

35363738394041 1851 - 1900 of 62973
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