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  • 2451.
    Yao, Yong
    et al.
    Blekinge Institute of Technology, School of Computing.
    Ngoga, Said Rutabayiro
    Blekinge Institute of Technology, School of Computing.
    Erman, David
    Blekinge Institute of Technology, School of Computing.
    Popescu, Adrian
    Blekinge Institute of Technology, School of Computing.
    Performance of Cognitive Radio Spectrum Access with Intra- and Inter-Handoff2012Conference paper (Refereed)
    Abstract [en]

    Opportunistic spectrum access (OSA) is a technology that allows unlicensed users to access spectrum holes and to provide so efficient use of radio resources. Most of the studies done on OSA focus on the situation when the unlicensed user performs the spectrum handoff only within a single cognitive radio network (so-called intra-handoff). In this paper, we consider the users (licensed or unlicensed) to be able to do inter-handoff among different cognitive radio cells as well. The cells provide priority to inter-handoff users. By considering multiple cells being in steady-state, the arrival rates of inter-handoff users are determined. We study the OSA performance of unlicensed users under both intra- and inter-handoff schemes, with respect to the blocking and forced-termination probabilities of unlicensed users as well as the unlicensed user service-completion and inter-handoff throughputs. Our Markov chain based numerical analysis is validated by simulation experiments.

  • 2452.
    Yao, Yong
    et al.
    Blekinge Institute of Technology, School of Computing.
    Ngoga, Said Rutabayiro
    Popescu, Adrian
    Blekinge Institute of Technology, School of Computing.
    A System for Spectrum Decision in Cognitive Radio Networks2012Conference paper (Refereed)
    Abstract [en]

    In Cognitive Radio (CR) networks, licensed radio channels are allowed to be used by Secondary Users (SUs) as long as SUs do not harmfully impair the transmission of Primary Users (PUs). Therefore, a crucial task for SUs is to decide which available channel should be selected, the so-called spectrum decision. To provide intelligent spectrum decision strategy to SUs, we suggest a system called Spectrum Decision Support System (SDSS). SDSS takes into account both heterogeneity aspects and interoperability requirements of CR networks. By this, SDSS is capable of jointly considering various channel characterizations and different decision making algorithms for doing spectrum decision. The paper is reporting the SDSS architecture as well as the related work-in-progress.

  • 2453.
    Yao, Yong
    et al.
    Blekinge Institute of Technology, School of Computing.
    Popescu, Alexandru
    Blekinge Institute of Technology, School of Computing.
    Ngoga, Said Rubatayiro
    Blekinge Institute of Technology, School of Computing.
    Popescu, Adrian
    Blekinge Institute of Technology, School of Computing.
    On Prioritized Spectrum Access in Cognitive Radio Networks with Imperfect Sensing2013Conference paper (Refereed)
    Abstract [en]

    Cognitive Radio networks allow the unlicensed users to share the available spectrum opportunities. However, this demands for solving the problem of contention among multiple unlicensed user packets for transmission. In our paper, we consider the Opportunistic Spectrum Access model for packet transmission between two unlicensed users. We suggest a priority scheme for a unlicensed user to concurrently transmit different types of packets. Our scheme reserves a fixed number of queueing places in the buffer for the prioritized packets. We study the transmission performance under both the priority scheme and imperfect spectrum sensing, with respect to the blocking probabilities, average transmission delay and transmission throughput of unlicensed users packets. The Markov chain based numerical analysis is validated by simulation experiments. Our results show that the suggested priority scheme is able to enhance transmission throughput of unlicensed users packets, together with significant decreased average transmission delay and minor decreased total transmission throughput.

  • 2454.
    Yao, Yong
    et al.
    Blekinge Institute of Technology, Faculty of Computing, Department of Communication Systems.
    Popescu, Alexandru
    Blekinge Institute of Technology, Faculty of Computing, Department of Communication Systems.
    Popescu, Adrian
    Blekinge Institute of Technology, Faculty of Computing, Department of Communication Systems.
    On Fuzzy Logic-Based Channel Selection in Cognitive Radio Networks2014In: Software-Defined and Cognitive Radio Technologies for Dynamic Spectrum Management / [ed] Kaabouch, Naima; Hu, Wen-Chen, Hershey, PA 17033, USA: IGI-Global , 2014Chapter in book (Refereed)
    Abstract [en]

    Cognitive radio networks are a new technology based on which unlicensed users are allowed access to licensed spectrum under the condition that the interference perceived by licensed users is minimal. That means unlicensed users need to learn from environmental changes and to take appropriate decisions regarding the access to the radio channel. This is a process that can be done by unlicensed users in a cooperative or non-cooperative way. Whereas the non-cooperative algorithms are risky with regard to performance, the cooperative algorithms have the capability to provide better performance. Our paper reports therefore a new fuzzy logic based decision making algorithm for channel selection. The underlying decision criterion considers statistics of licensed users channel occupancy as well as information about the competition level of unlicensed users. Our theoretical studies indicate that the unlicensed users can obtain an efficient sharing of the available channels. Simulation results are reported to demonstrate the performance and effectiveness of the suggested algorithm.

  • 2455.
    Yasam, Venkata Sudheer Kumar Reddy
    Blekinge Institute of Technology, School of Computing.
    An Optimized Representation for Dynamic k-ary Cardinal Trees2009Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    Trees are one of the most fundamental structures in computer science. Standard pointer-based representations consume a significant amount of space while only supporting a small set of navigational operations. Succinct data structures have been developed to overcome these difficulties. A succinct data structure for an object from a given class of objects occupies space close to the information-theoretic lower-bound for representing an object from the class, while supporting the required operations on the object efficiently. In this thesis we consider representing trees succinctly. Various succinct representations have been designed for representing different classes of trees, namely, ordinal trees, cardinal trees and labelled trees. Barring a few, most of these representations are static in that they do not support inserting and deleting nodes. We consider succinct representations for cardinal trees that also support updates (insertions and deletions), i.e., dynamic cardinal trees. A cardinal tree of degree k, also referred to as a k-ary cardinal tree or simply a k-ary tree is a tree where each node has place for up to k children with labels from 1 to k. The information-theoretic lower bound for representing a k-ary cardinal tree on n nodes is roughly (2n+n log k) bits. Representations that take (2n+n log k+ o(n log k ) ) bits have been designed that support basic navigations operations like finding the parent, i-th child, child-labeled j, size of a subtree etc. in constant time. But these could not support updates efficiently. The only known succinct dynamic representation was given by Diego, who gave a structure that still uses (2n+n log k+o(n log k ) ) bits and supports basic navigational operations in O((log k+log log n) ) time, and updates in O((log k + log log n)(1+log k /log (log k + log log n))) amortized time. We improve the times for the operations without increasing the space complexity, for the case when k is reasonably small compared to n. In particular, when k=(O(√(log n ))) our representation supports all the navigational operations in constant time while supporting updates in O(√(log log n )) amortized time.

  • 2456.
    Yasar, Fatma Gunseli
    et al.
    Izmir Katip Celebi Universitesi, TUR.
    Kusetogullari, Hüseyin
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science and Engineering.
    Underwater human body detection using computer vision algorithms2018In: 26th IEEE Signal Processing and Communications Applications Conference, SIU 2018, Institute of Electrical and Electronics Engineers Inc. , 2018, p. 1-4Conference paper (Refereed)
    Abstract [en]

    The number of studies to ensure the security when life-threatening unexpected events are encountered increases. Increasing of time spent under the water can cause the death of people. Thus, people who are in a risk of suffocation in the water must be found for early intervention and this process must be quick. The main contribution of this study is to detect and to track the people under the water quickly. Thresholding, Background Subtraction, Interframe Difference and Foreground Detection methods have been applied to create the silhouette of the people under the water. These methods have been demonstrated on videos which are found from internet. © 2018 IEEE.

  • 2457.
    Yasin, Affan
    et al.
    Blekinge Institute of Technology, School of Computing.
    Hasnain, Muhammad Ijlal
    Blekinge Institute of Technology, School of Computing.
    On the Quality of Grey Literature and its use in Information Synthesis during Systematic Literature Reviews2012Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    Context: The Internet has become a vital channel for disseminating and accessing scientific literature for both the academic and industrial research needs. Nowadays, everyone has wide access to scientific literature repositories, which comprise of both “white” and “Grey” literature. The “Grey” literature, as opposed to “white” literature, is non-peer reviewed scientific information that is not available using commercial information sources such as IEEE or ACM. A large number of software engineering researchers are undertaking systematic literature reviews (SLRs) to investigate empirical evidence in software engineering. The key reason to include grey literature during information synthesis is to minimize the risk of any bias in the publication. Using the state of the art non-commercial databases that index information, the researchers can make the rigorous process of searching empirical studies in SLRs easier. This study explains the evidence of Grey literature while performing synthesis in Systematic Literature Reviews. Objectives: The goals of this thesis work are, 1. To identify the extent of usage of Grey Literature in synthesis during systematic literature reviews. 2. To investigate if non-commercial information sources primarily Google Scholar are sufficient for retrieving primary studies for SLRs. Methods: The work consists of a systematic literature review of SLRs and is a tertiary study and meta-analysis. The systematic literature review was conducted on 138 SLRs’ published through 2003 until 2012 (June). The article sources used are IEEEXplore, ACM Digital Library, Springer-Link and Science Direct. Results: For each of the selected article sources such as ACM, IEEEXplore, Springer-link and Science Direct, we have presented results, which describe the extent of the usage of Grey literature. The qualitative results discuss various strategies for systematic evaluation of the Grey literature during systematic literature review. The quantitative results comprise of charts and tables, showing the extent of Grey literature usage. The results from analysis of Google Scholar database describe the total number of primary studies that we are able to find using only Google Scholar database. Conclusion: From the analysis of 138 Systematic Literature Reviews (SLRs’), we conclude that the evidence of Grey literature in SLRs is around 9%. The percentage of Grey literature sources used in information synthesis sections of SLRs is around 93.2%. We were able to retrieve around 96 % of primary studies using Google Scholar database. We conclude that Google Scholar can be a choice for retrieving published studies however; it lacks detailed search options to target wider pool of articles. We also conclude that Grey literature is widely available in this age of information. We have provided guidelines in the form of strategies for systematic evaluation of Grey literature.

  • 2458. Yeoh, Phee
    et al.
    Elkashlan, Maged
    Duong, Quang Trung
    Blekinge Institute of Technology, School of Computing.
    Yang, Nan
    Da Costa, Daniel
    Transmit antenna selection in cognitive relay networks with Nakagami-m fading2013Conference paper (Refereed)
    Abstract [en]

    We examine the impact of multiple primary receivers on cognitive multiple-input multiple-output (MIMO) relay networks with underlay spectrum sharing. For such a network, we propose transmit antenna selection with receive maximal-ratio combining (TAS/MRC) as an interference-aware design to satisfy the power constraints in the primary and secondary networks. To demonstrate this, we derive new closed-form expressions for the exact and asymptotic outage probability with TAS/MRC and decode-and-forward (DF) relaying over independent Nakagami-m fading channels in the primary and secondary networks. Several important design insights are reached. We find that the TAS/MRC strategy achieves a full diversity gain when the transmit power in the secondary network is proportional to the peak interference power in the primary network. Furthermore, we highlight that the diversity-multiplexing tradeoff (DMT) of TAS/MRC is independent of the primary network and entirely dependent on the secondary network.

  • 2459. Yeoh, Phee Lep
    et al.
    Elkashlan, Maged
    Duong, Quang Trung
    Blekinge Institute of Technology, School of Computing.
    Yang, Nan
    Leung, Cyril
    Cognitive MIMO relaying in Nakagami-m fading2013Conference paper (Refereed)
    Abstract [en]

    We propose transmit antenna selection with receive maximal-ratio combining (TAS/MRC) as an effective approach to reduce interference in cognitive multiple-input multiple-output (MIMO) relay networks. To demonstrate this, we derive new closed-form expressions for the exact and asymptotic outage probability of TAS/MRC with multiple antennas at the primary and secondary users. We consider underlay spectrum sharing where the secondary users (SUs) transmit in the presence of multiple primary users (PUs). We consider independent Nakagami-m fading in both the primary and secondary networks. Several important design insights are revealed. We find that TAS/MRC achieves a full diversity when the transmit power at the SUs is proportional to the peak interference power at the PUs. Furthermore, we highlight that this diversity gain is completely independent of the number of antennas at the PUs.

  • 2460. Ygge, Fredrik
    Market-Oriented Programming and its Application to Power Load Management1998Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Market-oriented programming is a new approach to design and implementation of resource allocation mechanisms in computer systems. It has its roots in different disciplines, such as economics and computer science (in particular the area of multi-agent systems. This thesis is divided into two different parts, focusing on: 1) central foundations and mechanisms of market-oriented programming, and 2) the use of market-oriented programming in practical applications. Market-oriented programming is seen as a programming paradigm based on abstractions such as prices and demands. Concepts, terminology and theory from micro-economics form the foundations of the paradigm. Central aspects of these foundations are investigated and some new insights are presented. Furthermore, some relations between standard optimization/resource allocation approaches and markets are described, and novel theorems are introduced. A plethora of algorithms (some stemming from mathematical optimization and numerical analysis, and some new) for the main computational problem of market-oriented programming -- the computation of general equilibrium -- are described, analyzed and compared. Some issues of self-interested agents in market-oriented programming are also investigated. A published, and generally recognized, market-oriented approach to the application building climate control is analyzed in some detail. A new approach to this application, based on market-oriented programming, is introduced and shown to be superior to the analyzed approach in many ways. The case study pinpoints a number of potential pitfalls as well as advantages of market-oriented approaches to this and other applications. A second investigated application is power load management, i.e. the management of loads at the customers' side for obtaining more efficient energy systems management. The basis of the application is described and a new market-oriented approach is introduced and analyzed. The approach is shown to have a number of advantages compared to existing approaches to this problem. The main conclusion of the thesis is that there are some potential pitfalls of market-oriented programming, but when used with care it provides a highly natural and efficient means for resource allocation in computer systems.

  • 2461. Ygge, Fredrik
    Power Load Management as a Multi-Commodity Market1997Report (Other academic)
    Abstract [en]

    The current report investigates the application of market-oriented programming to power load management. Power load management (or load management for short) is the management of loads at the customer side in order to manage energy systems more efficiently. As energy systems are very large and heavily distributed (typically including millions of loads in an area covering counties or countries), efficient and conceptually attractive methods are required for making load management successful. This report demonstrates how market-oriented programming can be utilized to meet the above demands.

  • 2462. Ygge, Fredrik
    et al.
    Akkermans, Hans
    Duality in Multi-Commodity Market Computations1997Report (Other academic)
    Abstract [en]

    In search for general equilibrium in multi-commodity markets, price-oriented schemes are normally used. That is, a set of prices (one price for each commodity) is updated until supply meets demand for each commodity. It is well known that in a two-commodity market resource-oriented schemes are conceivable. In this paper we demonstrate the duality between price- and resource-oriented schemes in the general multi-commodity case. We also discuss important properties of the two approaches. In resource-oriented schemes the resource constraint, which says that supply must equal demand, is always fulfilled, implying that at any time the auctioneer can provide a feasible allocation. This is not the case in price-oriented schemes outside market equilibrium. In this paper we introduce a novel any-time algorithm, Proportion, for the price-oriented scheme as well, that allows the auctioneer to deliver a suitable allocation at some deadline (possibly unknown in advance) also before market equilibrium is reached. We also show how the findings for the any-time algorithms can enable more efficient price-oriented markets.

  • 2463. Ygge, Fredrik
    et al.
    Akkermans, Hans
    Duality in Multi-Commodity Market Computations1997Conference paper (Refereed)
  • 2464. Ygge, Fredrik
    et al.
    Akkermans, Hans
    Making a Case for Multi-Agent Systems1997Conference paper (Refereed)
    Abstract [en]

    Multi agent systems (MAS) promise to offer solutions to problems where established, older paradigms fall short. To be able to keep promises, however, in depth studies of advantages and weaknesses of MAS solutions versus conventional ones in practical applications are needed. We offer one such study. Climate control in large buildings is one application area where MAS, and market oriented programming in particular, have been reported to be very successful. We have therefore constructed and implemented a variety of market designs for this problem, as well as different standard control engineering solutions. The paper gives a detailed analysis and comparison, so as to learn about differences between standard versus MAS approaches, and yielding new insights about benefits and limitations of computational markets.

  • 2465. Ygge, Fredrik
    et al.
    Akkermans, Hans
    Making a Case for Multi-Agent Systems1997Report (Other academic)
    Abstract [en]

    Multi-Agent Systems (MAS) promise to offer solutions to problems were established, older paradigms fall short. To be able to keep promises, however, in-depth studies of advantages and weaknesses of MAS solutions versus conventional ones in practical applications are needed. In this paper we offer one such study. Climate control in large buildings is one application area where MAS, and market-oriented programming in particular, have been reported to be very successful. We have therefore constructed and implemented a variety of market designs for this problem, as well as different standard control engineering solutions. This paper gives a detailed analysis and comparison, so as to learn about differences between standard versus MAS approaches, and yielding new insights about benefits and limitations of computational markets.

  • 2466. Ygge, Fredrik
    et al.
    Akkermans, Hans
    On Resource-Oriented Multi-Commodity Market Computations1998Report (Other academic)
    Abstract [en]

    In search for general equilibrium in multi-commodity markets, price-oriented schemes are normally used. That is, a set of prices (one price for each commodity) is updated until supply meets demand for each commodity. In some cases such an approach is very inefficient, and a resource-oriented scheme can be highly competitive. In a resource-oriented scheme the allocations are updated until the market equilibrium is found. It is well known that in a two-commodity market resource-oriented schemes are possible. In this paper we show that resource-oriented algorithms can be used for the general multi-commodity case as well, and present and analyze a specific algorithm. The algorithm has been implemented and some performance properties, for a specific example, are presented.

  • 2467. Ygge, Fredrik
    et al.
    Akkermans, Hans
    Power Load Management as a Computational Market1996Conference paper (Refereed)
    Abstract [en]

    Power load management enables energy utilities to reduce peak loads and thereby save money. Due to the large number of different loads, power load management is a complicated optimization problem. We present a new decentralized approach to this problem by modeling direct load management as a computational market. Our simulation results demonstrate that our approach is very efficient with a superlinear rate of convergence to equilibrium and an excellent scalability, requiring few iterations even when the number of agents is in the order of one thousand. A framework for analysis of this and similar problems is given which shows how nonlinear optimization and numerical mathematics can be exploited to characterize, compare and tailor problem-solving strategies in market-oriented programming.

  • 2468. Ygge, Fredrik
    et al.
    Akkermans, Hans
    Power Load Management as a Computational Market1996Report (Other academic)
    Abstract [en]

    Power load management enables energy utilities to reduce peak loads and thereby save money. Due to the large number of different loads, power load management is a complicated optimization problem. We present a new decentralized approach to this problem by modeling direct load management as a computational market. Our simulation results demonstrate that our approach is very efficient with a superlinear rate of convergence to equilibrium and an excellent scalability, requiring few iterations even when the number of agents is in the order of one thousand. A framework for analysis of this and similar problems is given which shows how nonlinear optimization and numerical mathematics can be exploited to characterize, compare, and tailor problem-solving strategies in market-oriented programming.

  • 2469. Ygge, Fredrik
    et al.
    Akkermans, Hans
    Smart Software as Customer Assistant in Large-Scale Distributed Load Management1997Report (Other academic)
    Abstract [en]

    Advanced information systems present a key enabling technology for innovative customer-oriented services by the utility industry. Real-time and two-way electronic information exchange with the customer over the power grid and other media is now possible. This provides the baseline for a host of new customer services, provided proper advantage is taken of a variety of recent advances in information technology. In this context, we discuss (a) how to engineer knowledge into systems and services, giving rise to smart software and intelligent systems, and (b) how to exploit this practically for novel ways to achieve distributed load management, dealing with thousands of devices simultaneously. A special characteristic of our concept is that the two-way information exchange for load-balancing purposes is based on market mechanisms similar to an auction. This auction is carried out by small smart software programs in devices (such as radiators) that represent and assist the customer. Field experiments with this intelligent and distributed new approach to power load management are currently performed.

  • 2470. Ygge, Fredrik
    et al.
    Akkermans, Hans
    Andersson, Arne
    A Multi-Commodity Market Approach to Power Load Management1998Report (Other academic)
    Abstract [en]

    Power load management is the concept of controlling the loads at the demand side in order to run energy systems more efficiently. Energy systems are inherently highly distributed and contain large number of loads, up to some million. This implies that computationally and conceptually attractive methods are required for this application. In this paper we give two novel theorems for how to decompose general resource allocation problems into markets. We also introduce a novel multi-commodity market design to meet the demands of power load management. The approach is demonstrated to lead to very high quality allocations, and to have a number of advantages compared to current methods.

  • 2471. Ygge, Fredrik
    et al.
    Astor, Eric
    Interacting Intelligent Software Agents in Demand Management1995Conference paper (Refereed)
    Abstract [en]

    Even though distributed computing and two-way communication with the customer is becoming a reality for many energy distribution companies, there is still a need to develop methodologies for more efficient energy management. In this paper we discuss current approaches to demand management, and then present ideas from other areas applied in energy management. We introduce concepts such as computational markets and software agents in this context. In addition, methods entirely based on distributed problem solving to address the computationally hard problems of resource allocation with vast number of clients are described. We also discuss how these methods can be used to perform cost/benefit analysis of demand management.

  • 2472. Ygge, Fredrik
    et al.
    Astor, Eric
    Interacting Intelligent Software Agents in Distribution management1995Report (Other academic)
    Abstract [en]

    Even though distributed computing and two-way communication with the customer is becoming a reality for many energy distribution companies, there still is a need to develop methodologies for more efficient energy management. In this paper we discuss current approaches to demand management, and then present ideas from other areas applied to energy management. We introduce concepts such as computational markets and software agents in this context. In addition, methods entirely based on distributed problem solving to address the computationally hard problems of resource allocation with vast number of clients are described. We also discuss how these methods can be used to perform cost/benefit analysis of demand management.

  • 2473. Ygge, Fredrik
    et al.
    Gustavsson, Rune
    Akkermans, Hans
    HOMEBOTS: Intelligent Agents for Decentralized Load Management1996Conference paper (Refereed)
  • 2474.
    Yousefi, Parisa
    et al.
    Blekinge Institute of Technology, School of Computing.
    Yousefi, Pegah
    Blekinge Institute of Technology, School of Computing.
    Cost Justifying Usability a case-study at Ericsson2011Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    In this study we investigate the level of usability and usability issues and the gaps concerning usability activities and the potential users, in a part of charging system products in Ericsson.Also we try identifying the cost-benefit factors, usability brings to this project, in order to attempt 'justifying the cost of usability for this particular product'.

  • 2475.
    Yousuf, Kamran
    Blekinge Institute of Technology, School of Computing.
    Time controlled network traffic shaper2010Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    Network performance metrics such as delay variations and packet loss influence the performance of the network. As a consequence, the performance of applications on the network is also affected as most of the networked applications existing today are very much sensitive to the network performance. Therefore it is of utmost importance to test the intensity of such network level disturbances on the performance of applications. A network traffic shaper/emulator shapes the network traffic in terms of these performance metrics to test such applications in a controlled environment. Most of the traffic shapers existing today give the instantaneous step transition in delay and packet loss on network. In this work, we present time-controlled network traffic shaper, a tool that facilitates testing and experimentation of network traffic through emulation. It focuses on time variant behavior of the traffic shaper. A linear transition of delay and packet loss that is varying with respect to time may fits much better to the real network scenarios instead of an instantaneous step transition in delay and packet loss. This work illustrates the emulation capabilities of time-controlled network traffic shaper and presents its design architecture. Several approaches are analyzed to do the task and one of them is followed to develop the desired architecture of the shaper. The shaper is implemented in a small scenario and is tested to see whether the desired output is achieved or not. The shortfalls in the design of the shaper are also discussed. Results are presented that show the output from the shaper in graphical form. Although the current implementation of the shaper does not provide linear or exponential output but this can be achieved by implementing a configuration setting that is comprised of small transition values that are varying with respect to very small step sizes of time e.g. transitions on milli seconds or micro seconds. The current implementation of the shaper configuration provides the output with a transition of one milli second on every next second.

  • 2476.
    Yusuf, Adewale
    Blekinge Institute of Technology, Faculty of Computing, Department of Creative Technologies.
    Challenges associated with effective task execution in a Virtual Learning Environment: A case study of Graduate Students of a University2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Context: In recent years, more and more people have started showing an increasing interest in distance or web-based education. Some of the reasons for this are the improvement in information and communication technology, as well as advancement in computer networking infrastructures. However, although computer technology has played an important role for the development of distance learning management systems, the underlying goal of such systems is the delivery of competitive and qualitative education via the distance learning environment. There have been a number of research studies and investigations in the field of Computer supported collaborative learning. This particular study is focused on the challenges associated with task execution in a distance learning environment as perceived by graduate students at a university.

    Objectives: The main focus or rationale behind this study is to investigate the importance of computer mediated communication tools in a virtual learning environment, as well as the problems facing the teachers or facilitators in their attempt to help learners (students) in the process of task execution, and towards achieving the learning goals in a web-based learning system.

    Methods: The author has adopted a qualitative case study approach. Questionnaires were sent out to some of the graduate students of BTH that participated in the online course under investigation, “Work integrated e-learning”, and some of these students were interviewed as well. Interviews were also conducted with two professors of Informatics and active researchers in distributed or e-learning in a University in Sweden that has had many years of experience in providing distance learning education. The empirical material was then analyzed, using cultural historical activity theory (CHAT) as a theoretical framework

    Results: The results indicate that more communication and collaborative interaction is needed in the context of the studied e-learning management system. The students expected the provision of more video communication through the learning platform. Furthermore, the results show that the learning in the studied web-based environment is centered on the students. 

    Conclusions: The author concludes that in order to diminish the gap that exists between face-to-face learning/teaching and an e-learning environment, there is a need for the designers and facilitators of the e-learning management system to make this platform more interactive. Additionally, the author concludes that the concept of Open start free pace (OSFP) or strict deadlines may need to be introduced into distance learning education in order to solve the challenges facing the teachers and facilitators.  

     

  • 2477.
    Yılmazer, Şafak Enes
    Blekinge Institute of Technology, School of Engineering.
    Integrated Coverage Measurement and Analysis System for Outdoor Coverage WLAN2011Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    Daily usage of Wireless Local Area Networks (WLAN) in business life for specific purposes has became much more critical than before since it is sometimes crucial to have wireless connectivity and seamless roaming around the working environment. In this thesis, steps required in order to design and implement a large scale outdoor IEEE 802.11g WLAN will be shown. This WLAN project has been deployed in north of Sweden and target coverage was an open area consisting of a deep pit mine, connecting roads, workshops, offices, dumps and storage areas. All telecommunications equipment used in this project is from the manufacturer Cisco using centralized solution. The special purpose of this project is to collect and analyze a series of coverage measurement data and correlate this data to predict the coverage area. Linux bash scripting and Gnuplot has been used to analyze coverage data. Finally, WRAP spectrum management and radio planning software has been used in modeling and designing of the whole network.

  • 2478. Zackrisson, Johan
    et al.
    Svahnberg, Charlie
    OpenLabs Security laboratory: The online security experiment platform2008Conference paper (Refereed)
    Abstract [en]

    For experiments to be reproducible, it is important to have a known and controlled environment. This requires isolation from the surroundings. For security experiments, e.g. with hostile software, this is even more important as the experiment can affect the environment in adverse ways. In a normal campus laboratory, isolation can be achieved by network separation. For an online environment, where remote control is essential, separation and isolation are still needed, and therefore the security implications must be considered. In this paper, a way to enable remote experiments is described, where users are given full control over the computer installation. By automating the install procedure and dynamically creating isolated experiment networks, remote users are provided with the tools needed to do experiments in a reproducible and secure environment.

  • 2479. Zackrisson, Johan
    et al.
    Svahnberg, Charlie
    OpenLabs Security Laboratory: The Online Security Experiment Platform2008In: International Journal of Online Engineering, ISSN 1868-1646, E-ISSN 1861-2121, Vol. 4, no special issue: REV2008, p. 63-68Article in journal (Refereed)
    Abstract [en]

    For experiments to be reproducible, it is important to have a known and controlled environment. This requires isolation from the surroundings. For security experiments, e.g. with hostile software, this is even more important as the experiment can affect the environment in adverse ways. In a normal campus laboratory, isolation can be achieved by network separation. For an online environment, where remote control is essential, separation and isolation are still needed, and therefore the security implications must be considered. In this paper, a way to enable remote experiments is described, where users are given full control over the computer installation. By automating the install procedure and dynamically creating isolated experiment networks, remote users are provided with the tools needed to do experiments in a reproducible and secure environment.

  • 2480.
    Zahda, Showayb
    Blekinge Institute of Technology, School of Computing.
    Obsolete Software Requirements2011Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    Context. Requirements changes are unavoidable in any software project. Requirements change over time as software projects progress, and involved stakeholders (mainly customers) and developers gain better understanding of the final product. Additionally, time and budget constraints prevent implementing all candidate requirements and force project management to select a subset of requirements that are prioritized more important than the others so as to be implemented. As a result, some requirements become cancelled and deleted during the elicitation and specification phase while other requirements are considered not important during the prioritization phase. A common scenario in this situation is to leave the excluded requirements for being considered in the next release. The constant leaving of the excluded requirements for the next release may simply render them obsolete.

  • 2481.
    Zalasinski, Marcin
    et al.
    Czestochowa University of Technology, POL.
    Cpalka, Krzysztof
    Czestochowa University of Technology, POL.
    Rakus-Andersson, Elisabeth
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mathematics and Natural Sciences.
    An Idea of the Dynamic Signature Verification Based on a Hybrid Approach2016In: Artificial Intelligence and Soft Computing LNAI 9693: Proceedings of the 15th International Conference, ICAISC 2016 / [ed] Leszek Rutkowski et al., Berlin Heidelberg: Springer, 2016, Vol. II, p. 232-246Conference paper (Refereed)
    Abstract [en]

    Dynamic signature verification is a very interesting biometric issue. It is difficult to realize because signatures of the user are characterized by relatively high intra-class and low inter-class variability. However, this method of an identity verification is commonly socially acceptable.

    It is a big advantage of the dynamic signature biometric attribute. In this paper, we propose a new hybrid algorithm for the dynamic signature verification based on global and regional approach. We present the simulation results of the proposed method for BioSecure DS2 database, distributed by the BioSecure Association.

  • 2482.
    Zeb, Falak
    et al.
    Blekinge Institute of Technology, School of Computing.
    Naseem, Sajid
    Blekinge Institute of Technology, School of Computing.
    Guidelines for the Deployment of Biometrics Technology in Blekinge Health Care System with the Focus on Human Perceptions and Cost Factor2010Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    Biometrics Technology is an authentication technology that identifies the individuals from their physical and behavioral characteristics. Despite the fact that biometrics technology provides robust authentication and enhanced security, it has not yet been implemented in many parts of the world due to certain issues i.e. human perceptions of the biometrics technology and cost factor, involved in the deployment of biometrics technology. As the biometrics technology involves identity management of individuals that’s why the humans perceptions of biometrics technology i.e. privacy concerns, security concerns and user acceptance issue play a very important role in the deployment of biometrics technology. There for the human perceptions and cost factor need to be considered before any deployment of biometrics technology. The aim of this thesis work is to study and analyze how the people’s perceptions and cost factor can be solved for the deployment of biometrics technology in Blekinge health care system. Literature study, interviews and survey are performed by authors for the identification and understanding of the human perceptions and cost factor. Based on these, solutions in form of guidelines to the issues involved in the biometrics technology deployment in Blekinge health care system Sweden are given.

  • 2483.
    Zeeshan, Ahmed
    Blekinge Institute of Technology, School of Engineering, Department of Interaction and System Design.
    Integration of Variants Handling in M-System-NT2006Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    This Master thesis proposes a solution to manage variabilities of software product line applications. The objective of the research is to support software decision makers in handling additional software complexity introduced by product line architectures. In order to fulfill this objective an approach to analyze, visualize, and measure product line specific characteristics of the C/C++ source code are proposed. The approach is validated in an empirical experiment using an open source software system. For that purpose the approach is first implemented into ®1 M-System-NT, an existing software measurement tool developed at Fraunhofer. The target hypothesis of the Institute for Experimental Software engineering research master thesis to perform static analysis of C/C++ source code, measure traditional and product line measures to identify the correlation between measures and indicate the fault proneness.

  • 2484.
    Zeeshan Iqbal, Syed Muhammad
    et al.
    Blekinge Institute of Technology, School of Computing.
    Grahn, Håkan
    Blekinge Institute of Technology, School of Computing.
    Törnquist Krasemann, Johanna
    Blekinge Institute of Technology, School of Computing.
    A Comparative Evaluation of Re-scheduling Strategies for Train Dispatching during Disturbances2012Conference paper (Refereed)
    Abstract [en]

    Railway traffic disturbances occur and train dispatchers make re-scheduling decisions in order to reduce the delays. In order to support the dispatchers, good rescheduling strategies are required that could reduce the delays. We propose and evaluate re-scheduling strategies based on: (i) earliest start time, (ii) earliest track release time, (iii) smallest buffer time, and (iv) shortest section runtime. A comparative evaluation is done for a busy part of the Swedish railway network. Our results indicate that strategies based on earliest start time and earliest track release time have the best average performance.

  • 2485.
    Zeid Baker, Mousa
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science and Engineering.
    Generation of Synthetic Images with Generative Adversarial Networks2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Machine Learning is a fast growing area that revolutionizes computer programs by providing systems with the ability to automatically learn and improve from experience. In most cases, the training process begins with extracting patterns from data. The data is a key factor for machine learning algorithms, without data the algorithms will not work. Thus, having sufficient and relevant data is crucial for the performance.

    In this thesis, the researcher tackles the problem of not having a sufficient dataset, in terms of the number of training examples, for an image classification task. The idea is to use Generative Adversarial Networks to generate synthetic images similar to the ground truth, and in this way expand a dataset. Two types of experiments were conducted: the first was used to fine-tune a Deep Convolutional Generative Adversarial Network for a specific dataset, while the second experiment was used to analyze how synthetic data examples affect the accuracy of a Convolutional Neural Network in a classification task. Three well known datasets were used in the first experiment, namely MNIST, Fashion-MNIST and Flower photos, while two datasets were used in the second experiment: MNIST and Fashion-MNIST.

    The results of the generated images of MNIST and Fashion-MNIST had good overall quality. Some classes had clear visual errors while others were indistinguishable from ground truth examples. When it comes to the Flower photos, the generated images suffered from poor visual quality. One can easily tell the synthetic images from the real ones. One reason for the bad performance is due to the large quantity of noise in the Flower photos dataset. This made it difficult for the model to spot the important features of the flowers.

    The results from the second experiment show that the accuracy does not increase when the two datasets, MNIST and Fashion-MNIST, are expanded with synthetic images. This is not because the generated images had bad visual quality, but because the accuracy turned out to not be highly dependent on the number of training examples.

    It can be concluded that Deep Convolutional Generative Adversarial Networks are capable of generating synthetic images similar to the ground truth and thus can be used to expand a dataset. However, this approach does not completely solve the initial problem of not having adequate datasets because Deep Convolutional Generative Adversarial Networks may themselves require, depending on the dataset, a large quantity of training examples.

  • 2486.
    Zepernick, Hans-Jürgen
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Signal Processing.
    Fiedler, Markus
    Blekinge Institute of Technology, School of Engineering, Department of Telecommunication Systems.
    Lundberg, Lars
    Blekinge Institute of Technology, School of Engineering, Department of Systems and Software Engineering.
    Pettersson, Mats
    Blekinge Institute of Technology, School of Engineering, Department of Signal Processing.
    Quality of Experience Based Cross-Layer Design of Mobile Video Systems2008Conference paper (Refereed)
    Abstract [en]

    This paper introduces and discusses quality of experience based cross-layer design of mobile video systems as a means of providing technologies for jointly analyzing, adopting, and optimizing system quality. The many benefits of our novel approaches over traditional concepts will range from efficient video processing techniques over advanced real-time scheduling algorithms, to networking and service level management techniques. This will lead to better service quality and resource utilization in mobile video systems.

  • 2487.
    Zhang, Ge
    Blekinge Institute of Technology, School of Engineering, Department of Interaction and System Design.
    Denial of Service on SIP VoIP infrastructures using DNS flooding2007Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    A simple yet effective Denial of Service (DoS) attack on SIP servers is to flood the server with requests addressed at irresolvable domain names. In this paper we evaluate different possibilities to mitigate these effects and show that over-provisioning is not sufficient to handle such attacks. As a more effective approach we present a solution called the DNS Attack Detection and Prevention (DADP) scheme based on the usage of a non-blocking DNS cache. Based on various measurements conducted over the Internet we investigate the efficiency of the DADP scheme and compare its performance with different caching strategies applied.

  • 2488. Zhang, Peng
    IMIS Platform Evaluation Report2005Report (Other academic)
    Abstract [en]

    After a pre-study in the year 2001-2002 financed by VINNOVA , a prototype based on the Activity Theory model was constructed to demonstrate the usability of mobile IT in mobile healthcare. The prototype was developed in PHP on Apache and deployed on a Microsoft Windows Server 2000 computer, which was also installed a MS SQL server 2000 for the database. This prototype is considered as a throwaway one, since it was developed mainly to demonstrate a basic architecture for the healthcare databases. As the IMIS project goes into more specific, there are needs for building up a new prototype, which is considered to be evolutionary prototype, i.e. a prototype to be successively constructed to the final system. To this purpose, this report will evaluate different development platforms for the new IMIS construction. This report evaluates two development platforms, namely Microsoft .Net and Java from Sun, which are most applied in software development.

  • 2489. Zhang, Peng
    Knowledge Integrated Agent Technology with CommonKADS2004Conference paper (Refereed)
    Abstract [en]

    This paper is organized around three questions: (1) is knowledge a necessary entity in Agent Systems? (2) What is the problem for individual knowledge intensive agents to cooperate? (3) Provide a possible methodology for design and implement a knowledge intensive agent. Knowledge is considered to be only emerging during the process when agents coordinate, but not an individually possessed entity by some researchers. Some other researchers consider knowledge as a starting point, a given entity that is part of the notion of an intelligent agent, and focus on knowledge acquisition, inference and communication. The paper will first have a discussion on this topic from an angle of Activity Theory. Then we have a discussion of the ontology sharing problems in MultiAgent Systems (MAS), based on the Distributed Collective Memory. Finally we introduce a methodology to build a knowledge intensive agent system.

  • 2490. Zhang, Peng
    Multi-agent Systems in Diabetic Health Care2005Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis discusses how Multi-agent Systems (MAS) should be designed in the context of diabetic health care. Three fields are touched: computer science, socio-psychology and systems science. Agent Technology is the core technology in the research. Theories from socio-psychology and systems science are applied to facilitate the discussion about computer agents. As the integration of socio-psychology and systems science, Activity Systems Theory is introduced to give a synthesized description of MAS. Laws and models are introduced with benefits on both individual agent and agent communities. Cybernetics from systems science and knowledge engineering from computer science are introduced to approach the design and implementation of the individual agent architecture. A computer agent is considered intelligent if it is capable of reactivity, proactivity and social activity. Reactivity and proactivity can be realized through a cybernetic approach. Social activity is much more complex, since it considers MAS coordination. In this thesis, I discuss it from the perspectives of socio-psychology. The hierarchy and motivation thinking from Activity Systems Theory is introduced to the MAS coordination. To behave intelligent, computer agents should work with knowledge. Knowledge is considered as a run-time property of a group of agents (MAS). During the MAS coordination, agents generate new information through exchanging the information they have. A knowledge component is needed in agent’s architecture for the knowledge related tasks. In my research, I adopt CommonKADS methodology for the design and implementation of agent’s knowledge component. The contribution of this research is twofold: first, MAS coordination is described with perspectives from socio-psychology. According to Activity Systems Theory, MAS is hierarchically organized and driven by the motivation. This thesis introduces a motivation-driven mechanism for the MAS coordination. Second, the research project Integrated Mobile Information Systems for health care (IMIS) indicates that the diabetic health care can be improved by introducing agent-based services to the care-providers and care-receivers. IMIS agents are designed with capabilities of information sharing, organization coordination and task delegation. To perform these tasks, the IMIS agents interact with each other based on the coordination mechanism that is discussed above.

  • 2491.
    Zhang, Peng
    Blekinge Institute of Technology, School of Engineering, Department of Interaction and System Design.
    Multi-Agent Systems Supported Collaboration in Diabetic Healthcare2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis proposes a holistic and hierarchical architecture to Multi-agent System design, in order to resolve the collaboration problem in diabetic healthcare system. A diabetic healthcare system is a complex and social system in the case that it involves many actors and interrelations. Collaborations among various healthcare actors are vital to the quality of diabetic healthcare. The collaboration problem is manifested by the problems of accessibility and interoperability. To support the collaboration in diabetic healthcare as such a complex and social system, the MAS must have corresponding social entities and relationships. Therefore, it is assumed that theories explaining social activity can be applied to design of MAS. Activity Theory, specifically its holistic triangle model from Engström and hierarchy thinking, provides theoretical supports to the design of individual agent architecture and MAS coordination mechanism. It is argued that the holistic and hierarchical aspects should be designed in a MAS when applied to the healthcare setting. The diabetic healthcare system is analyzed on three levels based on the hierarchy thinking. The collaboration problem is analyzed and resolved via MAS coordination. Based on the holistic activity model in Activity Theory, Müller’s Vertical Layered Architecture is re-conceptualized in the Control Unit and Knowledge Base design. It is also argued that autonomy, adaptivity and persona should be especially focused when designing the interaction between an agent system and human users. This study has firstly identified some important social aspects and the technical feasibility of embedding those identified social aspects in agent architecture design. Secondly, a MAS was developed to illustrate how to apply the proposed architecture to design a MAS to resolve the collaboration problem in diabetic healthcare system. We have designed and implemented an agent system – IMAS (Integrated Multi-agent System) to validate the research questions and contributions. IMAS system provides real time monitoring, diabetic healthcare management and decision supports to the diabetic healthcare actors. A user assessment has been conducted to validate that the quality of the current diabetic healthcare system can be improved with the introduction of IMAS.

  • 2492. Zhang, Peng
    et al.
    Bai, Guohua
    A Cybernetic Architecture of Practical Reasoning Agent2003Conference paper (Refereed)
    Abstract [en]

    During the last ten years, agent technology has been widely discussed in various research areas. An agent is a computer system that is situated in some environment, and that is capable of autonomous actions in this environment in order to meet its design objectives. There are at least two kinds of reasoning methods applied in constructing an agent, namely practical reasoning and theoretical reasoning. Practical reasoning directed towards actions – the process of figuring out what to do by weighing different acting options against with agent desires and believes. While theoretical reasoning is directed towards beliefs. In this paper, we just focus on practical reasoning. A widely used BDI model for practical reasoning agent will be introduced, based on which our cybernetic-BDI architecture is discussed. ‘Intelligence’ and ‘autonomy’ are perhaps the most important aspects of agent system. Attempts to model intelligent behaviors of an agent, especially a practical reasoning agent, have been made from areas of computer sciences, psychology, sociology, and many others. Cybernetics provides a concrete mechanism for this purpose, namely by ‘feedback’, ‘feedforward’, and ‘sociocybernetics’. We discuss first intelligent behaviors of agent systems in terms of reactivity, proactity, and social ability based on cybernetic concepts of feedback, feedforward, and sociocybernetics. Then based on the Belief-Desire-Intention (BDI) model and cybernetic principles we build up our Cybernetic-BDI architecture. With a pseudocode we validate the architecture for its practical implementation and fulfillment of required intelligent behaviors. In the last, a scenario of healthcare agent for diabetes patients is provided to show how the agent works according to the Cybernetic-BDI architecture.

  • 2493.
    Zhang, Peng
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Interaction and System Design.
    Bai, Guohua
    Blekinge Institute of Technology, School of Engineering, Department of Interaction and System Design.
    An Activity Systems Theory Approach to Agent Technology2005In: International Journal of Knowledge and Systems Sciences, ISSN 1349-7030, Vol. 2, no 1, p. 60-65Article in journal (Refereed)
    Abstract [en]

    In the last decade, Activity Theory has been discussed a lot in Human-Computer Interaction (HCI) and Computer Supported Cooperative Work (CSCW). Activity Theory was used both theoretically as an analytical method and practically as a development framework for Information Systems. Meanwhile, there is a new trench from Artificial Intelligence. Artificial Intelligence researchers find that the fruit from Activity Theory study may contribute, especially to Agent Technology, with socio-psychological aspects. In our E-health research, we apply Activity Theory both theoretically and practically into Agent Technology. To facilitate our research, General Systems Theory is chosen to integrate Activity Theory and Agent Technology. On the one hand, we consider Activity Theory as specific subject of General Systems Theory. On the other hand, General Systems Theory contributes to Agent Technology with systematic perspectives. As integration, we introduce Activity Systems Theory as an extension of Activity Theory. Then we apply it into Agent Technology discussion. The paper starts with the discussion of systematic perspectives of Activity Theory. Then we introduce Activity Systems Theory as an integration of systems science and Activity Theory. Three Activity Systems Theory principles are then applied into the discussion of Agent Technology. In the end, we introduce how we apply Activity Systems Theory into an E-health application.

  • 2494.
    Zhang, Peng
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Interaction and System Design.
    Bai, Guohua
    Blekinge Institute of Technology, School of Engineering, Department of Interaction and System Design.
    Systemic Thinking in Multi-agent Systems Coordination – Applied in Diabetic Health Care2006Conference paper (Refereed)
    Abstract [en]

    Computer agent is considered as a technology that may support human beings with automatic functionalities in the social environment. This paper describes an approach to applying agents to diabetic health care. A good health care agent is considered to be able to keep a good balance between individual flexibility and team control. A systemic approach is proposed hereby as a complementation to the current approaches. Multi-agent Systems (MAS) coordination is considered on three levels: collaboration, coordination and communication. In the end, an agent-based computer system – Integrated Mobile Information Systems (IMIS) – is discussed based on the systemic approach.

  • 2495.
    Zhang, Peng
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Interaction and System Design.
    Bai, Guohua
    Blekinge Institute of Technology, School of Engineering, Department of Interaction and System Design.
    Carlsson, Bengt
    Blekinge Institute of Technology, School of Engineering, Department of Interaction and System Design.
    Johansson, Stefan J.
    Blekinge Institute of Technology, School of Engineering, Department of Interaction and System Design.
    Applying Multi-agent Systems Coordination to the Diabetic Healthcare Collaboration2008Conference paper (Refereed)
    Abstract [en]

    Diabetic healthcare is characterized by the collaboration problem, which is manifested by problems of accessibility and interoperability. To improve the problem situation, we propose a Multi-agent Systems approach. The interactions among the diabetic healthcare actors are categorized on three levels: collaboration, coordination, and communication. Agents are designed to work on the coordination and communication levels, and support the collaboration among human actors. This paper presents a project Integrated Mobile Information Systems for diabetic healthcare (IMIS) to demonstrate how to apply Multi-agent Systems coordination to the collaboration among healthcare actors.

  • 2496. Zhang, Peng
    et al.
    Carlsson, Bengt
    Johansson, Stefan J.
    Enhance Collaboration in Diabetic Healthcare for Children using Multi-agent Systems2008Conference paper (Refereed)
    Abstract [en]

    We developed a multi-agent platform as a complement to the existing healthcare system in a children’s diabetic healthcare setting. It resolves problems related to the difficulty of collaboration between the stakeholders of the problem domain. In addition, it gives us an opportunity to support the decision making of the stakeholders using Multi-agent Systems. The collaboration situation is believed to be improved by the agent-based services, such as, diabetes monitoring and alarm, scheduling, and task delegation.

  • 2497.
    Zhang, Yiran
    et al.
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science and Engineering.
    Liu, Xiaohui
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science and Engineering.
    Design of Eco-Smart Homes For Elderly Independent Living2015Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    The aging of the world population has increased dramatically during the past century. The rapid increase of elderly population is putting a heavy strain on healthcare and social welfare. Living conditions and service provision for elderly people have thus become an increasingly hot topic worldwide. In this paper, we address this problem by presenting a conceptual model of an integrated and personalized system for an eco-smart home for elderly independent living. This approach was inspired by an on-going European project, INNOVAGE, which researchers at Blekinge Institute of Technology are currently participating in, and which focuses on regional knowledge clusters for promoting eco-smart homes for elderly independent living. Contrasting the social situation of elderly in China and Europe, we have chosen to focus on a solution for a Swedish context, which takes technical, environmental, social and human-computer interaction aspects into consideration in the design of eco-smart homes for elderly people in Sweden. Three studies have been carried out in order to clarify and explore the main issues at stake. A literature review gave an overview of on-going research and the current state-of-the-art concerning smart homes. The literature review, along with an interview of an expert on solar energy, also gave insights into additional design challenges which are introduced when focusing specifically on eco-smart building solutions. In order to explore and gain a better understanding of the perceived needs and requests of the target group, i.e. the elderly population, we carried out interviews with three experts in healthcare and homecare for the elderly, and also carried out interviews among the elderly in Karlskrona and interviews and a web survey among the elderly in China. As a way of addressing the design challenges of integrating a multitude of diverse, complicated technical systems in a home environment while at the same time high-lighting the need for comprehensive personalized service provision for elderly people, we designed a conceptual model – an exemplar – of an eco-smart home for elderly independent living. The eco-smart home exemplar aims to inspire interdisciplinary and multi-stakeholder discussions around innovative design and development of environmentally friendly, comfortable, safe and supportive living for the elderly in the future. Finally, we did an evaluation of the model in two workshops with elderly people in two different towns in Blekinge.

  • 2498. Zhao, Haifeng
    et al.
    Kallander, William
    Gbedema, Tometi
    Johnson, Henric
    Wu, Felix
    Read what you trust: An open wiki model enhanced by social context2011Conference paper (Refereed)
    Abstract [en]

    Wiki systems, such as Wikipedia, provide a multitude of opportunities for large-scale online knowledge collaboration. Despite Wikipedia's successes with the open editing model, dissenting voices give rise to unreliable content due to conflicts amongst contributors. From our perspective, the conflict issue results from presenting the same knowledge to all readers, without regard for the importance of the underlying social context, which both reveals the bias of contributors and influences the knowledge perception of readers. Motivated by the insufficiency of the existing knowledge presentation model for Wiki systems, this paper presents TrustWiki, a new Wiki model which leverages social context, including social background and relationship information, to present readers with personalized and credible knowledge. Our experiment shows, with reliable social context information, TrustWiki can efficiently assign readers to their compatible editor community and present credible knowledge derived from that community. Although this new Wiki model focuses on reinforcing the neutrality policy of Wikipedia, it also casts light on the other content reliability problems in Wiki systems, such as vandalism and minority opinion suppression.

  • 2499. Zhao, Haifeng
    et al.
    Kallander, William
    Johnson, Henric
    Blekinge Institute of Technology, School of Computing.
    Wu, Felix
    Blekinge Institute of Technology, School of Computing.
    SmartWiki: A reliable and conflict-refrained Wiki model based on reader differentiation and social context analysis2013In: Knowledge-Based Systems, ISSN 0950-7051, E-ISSN 1872-7409, Vol. 47, p. 53-64Article in journal (Refereed)
    Abstract [en]

    Wiki systems, such as Wikipedia, provide a multitude of opportunities for large-scale online knowledge collaboration. Despite Wikipedia's successes with the open editing model, dissenting voices give rise to unreliable content due to conflicts amongst contributors. Frequently modified controversial articles by dissent editors hardly present reliable knowledge. Some overheated controversial articles may be locked by Wikipedia administrators who might leave their own bias in the topic. It could undermine both the neutrality and freedom policies of Wikipedia. As Richard Rorty suggested "Take Care of Freedom and Truth Will Take Care of Itself"[1], we present a new open Wiki model in this paper, called TrustWiki, which bridge readers closer to the reliable information while allowing editors to freely contribute. From our perspective, the conflict issue results from presenting the same knowledge to all readers, without regard for the difference of readers and the revealing of the underlying social context, which both causes the bias of contributors and affects the knowledge perception of readers. TrustWiki differentiates two types of readers, "value adherents" who prefer compatible viewpoints and "truth diggers" who crave for the truth. It provides two different knowledge representation models to cater for both types of readers. Social context, including social background and relationship information, is embedded in both knowledge representations to present readers with personalized and credible knowledge. To our knowledge, this is the first paper on knowledge representation combining both psychological acceptance and truth reveal to meet the needs of different readers. Although this new Wiki model focuses on reducing conflicts and reinforcing the neutrality policy of Wikipedia, it also casts light on the other content reliability problems in Wiki systems, such as vandalism and minority opinion suppression.

  • 2500. Zhi, Tao
    et al.
    Zhang, Xia-Jun
    Zhao, He-Ming
    Kulesza, Wlodek J.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Applied Signal Processing.
    Noise reduction in whisper speech based on the auditory masking model2010Conference paper (Refereed)
    Abstract [en]

    This paper presents the issue of whispered speech enhancement. Based on multi-band spectral subtraction method where the introduced musical residual noise occurs, the proposed approach performs parametric subtraction according to the WSS (Whispered Sensitive Scale) method that is particular for whispered speech processing and auditory masking model. The algorithm is characterized by a tradeoff mechanism between the amount of the whispered speech distortion, noise reduction, and the level of musical residual noise, which are determined by appropriate adjusting the subtraction parameters. Compared with traditional subtractive-type algorithms, the proposed method results in a significant reduction of musical residual noise. Finally, objective and subjective evaluations are implemented illustrating the improvements over traditional subtractive-type algorithms.

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