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  • 251.
    Davidsson, Paul
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Johansson, Stefan J.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    On the Potential of Norm-Governed Behavior in Different Categories of Artificial Societies2006Ingår i: Computational and mathematical organization theory, ISSN 1381-298X, E-ISSN 1572-9346, Vol. 12, nr 2-3, s. 169-80Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Based on a classification of artificial societies and the identification of four different types of stakeholders in such societies, we investigate the potential of norm-governed behavior in different types of artificial societies. The basis of the analysis is the preferences of the stakeholders and how they influence the state of the society. A general conclusion drawn is that the more open a society is the more it has to rely on agent owners and designers to achieve norm-governed behavior, whereas in more closed societies the environment designers and owners may control the degree of norm-governed behavior.

  • 252. Davidsson, Paul
    et al.
    Persson, Jan A.
    Jacobsson, Andreas
    An agent-based approach to transport chain management2009Konferensbidrag (Refereegranskat)
    Abstract [en]

    A novel application of agent-mediated electronic commerce is presented. It concerns developing and maintaining efficient and effective transport solutions. The suggested approach is inspired by the concepts of virtual enterprises and breeding environments, as well as peer-to-peer technology. We discuss the requirements of such an approach and outline a software architecture meeting these requirements.

  • 253.
    Davuluru, Tharashasank
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Echezona, Ude Francis
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    OSS Success factors when going open: Systematic Literature Review2011Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [sv]

    Context/Background: The adoption of Open Source Software involves more than using OSS products and this has marked a new trend in software development. This new practice has potential benefits while introducing peculiar practical challenges in software development; particularly in areas concerning OSS selection. This involves OSS search and establishment of selection criteria which selects the best OSS product that matches the system requirements. These challenges have also introduced significant bottlenecks into software development industry. In order to mitigate or solve these problems, there isa need to identify OSS success factors for any software development firm that wants to go OPEN. Objective: This thesis aims to investigate the benefits and limitations of adopting OSS and to identify the success factors that lead to the benefits of OSS in software development. Method: Systematic literature review, through searches in library databases, was used to review empirical studies on OSS success factors when going OPEN. The data was extracted and synthesized from the selected papers for analysis. Mapping was used to obtain information concerning the OSS success factors when going OPEN, benefits, limitations/bottlenecks encountered in the industry, and were used to validate our findings from the literature. Results: Ninety three papers were identified. The data extraction from the SLR helped to identify the success factors, benefits and the bottlenecks from the literatures in the past decade. Conclusion: The implications of our thesis are two fold; practitioners should be acquainted with the benefits and limitations of adopting OSS and also learn from our identified success factors that leads to benefits in software development. This will help them when going OPEN. Alternatively, researchers should align their work and try to identify more knowledge gaps using our identified bottlenecks/limitations for software organizations when going OPEN.

  • 254. de Kaminski, Marcin
    et al.
    Svensson, Måns
    Larsson, Stefan
    Olsson, Johanna Alkan
    Rönkkö, Kari
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Studying Norms and Social Change in a Digital Age: Identifying and Understanding a Multidimensional Gap Problem2013Ingår i: Social and Legal Norms: Towards a Socio-Legal Understanding of Normativity / [ed] Baier, M, Ashgate, 2013, s. 309-330Kapitel i bok, del av antologi (Övrigt vetenskapligt)
  • 255. Demirors, Onur
    et al.
    Gencel, Cigdem
    Conceptual Association of Functional Size Measurement Methods2009Ingår i: IEEE Software, ISSN 0740-7459 , Vol. 26, nr 3, s. 71-78Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    One of the significant challenges of Functional Size Measurement (FSM) is the underlying variations among FSM methods. A software product has different functional sizes in different units of measurement when measured by different methods. On the other hand, FSM methods are based on similar concepts and use comparable attributes in their measurement processes. In this paper the conceptual similarities and differences between FSM methods are discussed and a model for unification is introduced. The model is evaluated by means of case studies for measuring the functional size of software systems simultaneously by using IFPUG FPA, MkII FPA and COSMIC FFP methods.

  • 256.
    Demirsoy, Ali
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Using Semantic Knowledge Management Systems To Overcome Information Overload Problems In Software Engineering2013Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Context. Information overload is an increasingly important problem of our age where the amount of data we have is expanding drastically with the use of digital communication. Information retrieval models are developed to help overcoming this problem with computerized tools. Semantic information retrieval, which means retrieving information based on the interpretations of meanings of the words, is one of these models and started to be used commonly to handle large amount of data in the Internet and in enterprises to overcome information overload problems. Objectives. In this study we investigate different information retrieval models for using with knowledge management systems in large-scale organizations from the perspective of software engineers. To this end, we aim at identifying existing issues and needs about information overload and then assessing different solutions against these needs. Afterwards, we analyze the chosen solution, which is semantic search, and define and carry out an implementation process to reflect on it. Finally, the usefulness and feasibility of this type of solutions to overcome the specified information overload problems in software engineering is studied and discussed. Methods. We performed a literature review to extract the existing knowledge, technology, and the problems and solutions in the defined context. Then a case study was conducted at a development site of Ericsson AB in Sweden. Case study involved unstructured and semi-structured interviews for data collection, and an implementation attempt for a simple semantic knowledge management system. Thematic Coding Analysis method is used for qualitative data analysis. Results. We identified 23 codes that are categorized under 8 themes from the opinions of company practitioners about semantic knowledge management systems. They are mainly about the existing problems, arguments for using semantic system for solving them, and suggestions and challenges. Conclusions. We conclude that semantic knowledge management systems have a very high potential to solve information overload problems in software engineering if the necessary measures are taken. We found that the problems are related to search engine and the document structure of the tools; usefulness of semantic system is the capability of ontology based retrieval to filter out irrelevant documents and extract hidden data and people’s skills and interests; and finally the challenge is the necessary endeavor to elicit and satisfy all the needs.

  • 257.
    Denys, Paul
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Security of Personal Information in Cloud Computing: Identifying and mitigating against risks to privacy in the deployment of Enterprise Systems Applications on the Software as a Service platform2012Självständigt arbete på avancerad nivå (magisterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    The emergence and subsequent growth of Cloud computing has brought with it a great deal of change in the manner in which the world undertakes to compute and store information. This new technology has brought with it immense possibilities as far as processing of information and the pooling of resources is concerned. This potential has also been noticed by the public sector, as Governments all over the world have undertaken to introduce what has come to be known as e-Government, the provisioning of Government services and communications via Web based applications, rather than the traditional means of in person contact and paper based collection of personal information. While the move to Web based Government has been occurring for the last 20 or so years, a new development in this area is the introduction of Cloud computing and Cloud-based computing platforms, most notably Software-as-a-Service (SaaS) in the provisioning of these services. The computing and efficiency potential of this technology cannot be disputed, yet it’s important to recognize that taking advantage of this computing power does come at a price. That price being significant threats to personal privacy and security of personally identifiable information. This thesis will make it easier for government agencies to make informed decisions about whether or not to migrate data and applications into the cloud. The identification and analysis of potential risks to data security and personal information has drawn together key information from a multitude of both academic and industry sources to make such a decision plausible.

  • 258.
    Dhungana, Ramesh
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Shahi, Deepak
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    A Quantitative Study of Quality of Experience (QoE) for Decreasing and Increasing Network Performance.2011Självständigt arbete på grundnivå (kandidatexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Currently, user satisfaction is becoming one of the major concerns for the service provider in accommodating user demand. This paper evaluates the user’s perception (Quality of Experience, QoE) of the increasing and decreasing response times (Quality of Service, QoS), in particular a login to web login page by the implementation of Mean Opinion Score (MOS). By comparing the results to user perception of web login performance, we show that the users perceive web login for increasing and decreasing RTs in different ways. So, we conduct interview among specific users applying increased and decreased RTs in particular web login to rank the users satisfaction level. Study of the two results for RTs of the web login page is presented.

  • 259.
    Dinparvar, Mahdi
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Torabi, Navid
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Toward a Web-based Application to Resolve Physical Pulse Board Issues2013Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    A decade ago, Toyota, an automobile manufacturer from Japan, came up with a new production system which started the automobile industry called “Lean manufacturing”. Over time, the popularity of the system became apparent and it became the Toyota Production System (TPS). Following this technological development, “Len enterprise” a new concept was produced with the sole purpose of eliminating wastes in every function of the entire organization. As of present, as far as product developing companies are concerned, the development process has become more complex. For instance, in Scrum software development as well as in Lean product development, tools for planning a project using walls and boards have been developed. These methods have so far proved to be very efficient, in so far as the visualization of the work performed, as well as the prioritization of new tasks is concerned. However, there are notable challenges in synchronization, version control and traceability among a company’s different projects. This thesis, investigates how Physical Pulse Board is used and how it can be improved through the introduction of a web-based application for eliminating of difficulties of using Pulse board especially in global environment where different people from various locations might need to join the meeting. The paper consists of three parts. In the first part one set of interviews were conducted along with an observation to figure out related difficulties with the use of Physical Pulse Board especially in global environment. Following this, another set of interviews were conducted to help find out how these issues can be eliminated or resolved. Considering that good principles can never be useful, unless they are applied and used in reality, in the second part of this report, a web-based application was developed to help bring improvements using Pulse Board in global environment based on the finding from the first part. It was then that evaluation of implemented software was done through a workshop with Hellström, and Dr. Amer Ćatić. It is worth noting that the two persons are the Lean Product Development Specialist chosen for market analysis given that the two had implemented the Physical Pulse Board in their organization.

  • 260.
    Donkena, Kaushik
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Gannamani, Subbarayudu
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Performance Evaluation of Cloud Database and Traditional Database in terms of Response Time while Retrieving the Data2012Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Context: There has been an exponential growth in the size of the databases in the recent times and the same amount of growth is expected in the future. There has been a firm drop in the storage cost followed by a rapid increase in t he storage capacity. The entry of Cloud in the recent times has changed the equations. The Performance of the Database plays a vital role in the competition. In this research, an attempt has been made to evaluate and compare the performance of the traditional database and the Cloud Database. Objectives: This thesis investigates about the prior works on the issues that affect the performance of Cloud Database. And compares the performance of a Database in Traditional to that Cloud Environments Methods: Two different research methods are used to carry the research. They are Systematic Literature Review (SLR) and Quantitative Methodology. Articles from Scientific Databases are chosen for SLR process. Results: From the SLR process, 4 issues were identified. From the Experimentation results, Cloud Database is having poor performance compared to the Traditional Database. Conclusions: Issues that affect the performance of Cloud Database are identified and a test bed is created to test the performance of a Database. Attempts are to be made to improve the performance of Cloud Database.

  • 261. Doroud, Mina
    et al.
    Bhattacharyya, Prantik
    Wu, Felix
    Felmlee, Diane
    The evolution of ego-centric triads: A microscopic approach toward predicting macroscopic network properties2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    Scalability issues make it time-consuming to estimate even simple characteristics of large scale, online networks, and the constantly evolving qualities of these networks make it challenging to capture a representative picture of a particular networks properties. Here we focus on the evolution of all triads (ties between three nodes) in a graph, as a method of studying change over time in large scale, online social networks. For three month snapshots, we examine, and predict, transitions among all sixteen triad types (i.e., triad census) in a sample of three years of Facebook wall-post interactions. We introduce a new sampling approach for examining triads in online graphs, based on ego-centric networks of random seeds. We examine tendencies in the data toward properties related to balance theory, including structural balance, clusterability, ranked clusters, transitivity, hierarchical clusters, and the presence of "forbidden" triads. In a time series analysis, we successfully predict the evolution over time in the wall post network dataset, with relatively low levels of error. The findings demonstrate the utility of our ego- centric, two-step, random seed sampling approach for studying large scale networks and predicting macroscopic graph properties, as well as the advantages of examining transitions in the complete triad census for an online network.

  • 262.
    Drwal, Maciej
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Data mining in distributedcomputer systems2009Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    The thesis presents a survey of techniques for accurate prediction of traffic distribution in computer network systems.

  • 263. Du, Xu
    et al.
    Vo, Nguyen-Son
    Cheng, Wenqing
    Duong, Quang Trung
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Shu, Lei
    Joint Replication Density and Rate Allocation Optimization for VoD Systems over Wireless Mesh Networks2013Ingår i: IEEE transactions on circuits and systems for video technology (Print), ISSN 1051-8215, E-ISSN 1558-2205, Vol. 23, nr 7, s. 1260-1273Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Due to the limited resources and dynamically varying nature of wireless links, guaranteeing high quality demands for a large number of heterogeneous users is very challenging in video streaming over wireless networks. In this paper, we introduce a layered multiple description coding with an embedded forward error correction scheme (LMDC-FEC). The combination of layered MDC and FEC aims at coping with not only the diverse bandwidth and unreliability of wireless links but also the heterogeneous user devices. We further propose a joint replication density and rate allocation (RD-RA) optimization problem in the context of video on-demand systems (VoDs) over wireless mesh networks (WMNs), and employ a genetic algorithms based approach to solve the optimization problem. Our objective is to elaborately distribute proper replication density for each video segment and allocate optimal bit rate to each layer of each segment in order to gain high userperceived quality (UPQ) with small consumption of storage resource. By this method, both optimal replication densities and rate allocations are found in accordance with the access rate of segments, the diverse loss characteristics of descriptions in each segment, and the rate–distortion relationship of segments, so as to thoroughly optimize UPQ and storage resource consumption. Simulation results demonstrate that our proposed method significantly enhances the streaming performance of VoDs over WMNs.

  • 264.
    Duarte, Carlos Henrique C.
    et al.
    BNDES, Brazilian Dev Bank, BRA.
    Gorschek, Tony
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för programvaruteknik. Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Technology Transfer - Requirements Engineering Research to Industrial Practice An Open (Ended) Debate2015Ingår i: 2015 IEEE 23RD INTERNATIONAL REQUIREMENTS ENGINEERING CONFERENCE (RE), IEEE , 2015, s. 414-415Konferensbidrag (Refereegranskat)
    Abstract [en]

    Technology and knowledge have been recognized as main sources of competitive advantage of corporations, industries and nations, particularly in the software domain. They have led to the creation of local ecosystems devoted to development and transfer activities, which ensure not only personal and institutional motivation/recognition, but also social and economic gains. An open (ended) debate panel is proposed in order to develop greater awareness and seek deeper understanding of such activities from Requirements Engineering research to industrial practice. The panel involves researchers and practitioners with the perspective of eliciting: (i) experiences in knowledge and technology development and transfer; (ii) awareness and effectiveness of models and patterns; and (iii) factors for having successful collaboration between research institutions and industry. The organizers also plan to run a survey during and after the conference, summarizing their conclusions in specific post-conference reports.

  • 265.
    Duc, Anh Nguyen
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    The impact of design complexity on software cost and quality2010Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Context: Early prediction of software cost and quality is important for better software planning and controlling. In early development phases, design complexity metrics are considered as useful indicators of software testing effort and some quality attributes. Although many studies investigate the relationship between design complexity and cost and quality, it is unclear what we have learned from these studies, because no systematic synthesis exists to date. Aim: The research presented in this thesis is intended to contribute for the body of knowledge about cost and quality prediction. A major part of this thesis presents the systematic review that provides detail discussion about state of the art of research on relationship between software design metric and cost and software quality. Method: This thesis starts with a literature review to identify the important complexity dimensions and potential predictors for predicting external software quality attributes are identified. Second, we aggregated Spearman correlation coefficients and estimated odds ratios from univariate logistic regression models from 59 different data sets from 57 primary studies by a tailored meta-analysis approach. At last, it is an attempt to evaluate and explain for disagreement among selected studies. Result: There are not enough studies for quantitatively summarizing relationship between design complexity and development cost. Fault proneness and maintainability is the main focused characteristics that consume 75% total number of studies. Within fault proneness and maintainability studies, coupling and scale are two complexity dimensions that are most frequently used. Vote counting shows evidence about positive impact of some design metrics on these two quality attributes. Meta analysis shows the aggregated effect size of Line of code (LOC) is stronger than those of WMC, RFC and CBO. The aggregated effect sizes of LCOM, DIT and NOC are at trivial to small level. In subgroup analysis, defect collections phase explains more than 50% of observed variation in five out of seven investigated metrics. Conclusions: Coupling and scale metrics are stronger correlated to fault proneness than cohesion and inheritance metrics. No design metrics are stronger single predictors than LOC. We found that there is a strong disagreement between the individual studies, and that defect collection phase is able to partially explain the differences between studies.

  • 266.
    Duc, Tran Huy
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Designing distance learning for the 21st century: Constructivism, Moore’s transactional theory and Web 2.02012Självständigt arbete på avancerad nivå (magisterexamen)Studentuppsats (Examensarbete)
    Abstract [sv]

    In my thesis, I have discussed the role of distance-learning and have discussed how constructivism makes better education, Moore’s analysis that distance education is naturally education and thus what makes education makes good distance education. Better education according to Moore is when you can reduce “transactional distance” by influencing its makeup dialogue, structure and learner autonomy. I also looked at examples of where Web 2.0 has been successfully applied to reduce “transactional distance” grounded in Moore’s theory. I looked at the humble historical context of distance-learning and the spectacular achievements that distance-education teachers and students despite all those forces against change. I discussed the development of distance-education to become what it is today. I believe technologies are part of the solution but also we need strong pedagogy and a rigorous framework to guide it. The discussion of constructivism vs. objectivism showed the contrasting differences as well as certain overlapping elements of both ideologies. I believe constructivism was the pedagogy of the 21st century which involves a great deal of personal reflection, interaction among course peers and teachers as well as a shift in how education must be organized. Moore’s theory of transactional distance is grounded in constructivist pedagogy but has his fair share of genius thought. First, he convinced us that distance education is also education because the distance in distance education or what Moore called “transactional distance” also exists in face-to-face classroom education, to make better distance learning means to reduce “transactional distance”. Second, his ability to benchmark an operational framework to organize distance education and measure transactional distance as a result or influencing the three variables dialogue, structure and learner autonomy. His work has been proved by Saba (1994) with dynamic systems modeling as well as questioned by few critics of his poor theory construction as well as unconvincing empirical data gathered from a few studies. However, Moore’s theory of transactional distance is still the prominent theory and Moore himself a leading figure in the field. Transactional theory is realized by a new wave of highly interactive web technologies built on the architecture of openness and participatory. This plays well into constructivism of build a virtual learning community for collaborative learning. We looked at a prime example of employing Web 2.0 technologies for better distance education by Kane and Fichman (2009). The benefits of instruction activities that otherwise would not be possible without Web 2.0 have been analyzed and evaluated using Moore’s variables to yield a positive result. I also demonstrated a personal experience being part of a distance learning course at Umea University in Spring semester 2010 where we all learned about distance learning in the modern age and apply constructivism pedagogy and Moore’s transaction theory distance in evaluating the course. Understanding the theory makes me a better student because I know what makes effective learning and also further confirm my belief in the mandate of distance education, a distance education for all because you can’t learn individually. Kane and Fichman (2009) have surprised me to the extent of their creative ideas of applying Web 2.0 in education such as the idea of crowdsourcing and peer review by wikis. Able to use technologies especially in a live environment such as the course at Umea University gave me a real sense of gaps between theory and practice.

  • 267.
    Dulal, Nabin Raj
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Maharjan, Sabindra
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    A Comparative Study of Component Based Regression Testing Approaches without Source Code2011Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Context: Today, most of the software products are built with COTS components. When a new version of these components is available, it is difficult to perform testing as the vendors of the component do not usually provide source code. Various regression testing techniques have been developed, but most of the techniques are based on the source code for change identification. So, the testers are facing different challenges in performing effective testing. Objectives: The goal of this research is to find out the different approaches that are used to identify changes in modified COTS component, analyze the main characteristics of those approaches and investigate how these characteristics can be used in selection and development of CBRT approach. Methods: To fulfill the aims of the research, we have conducted systematic literature review of different CBRT approaches from the year 1993-2010. From systematic literature we found out 32 papers relevant to our study. Data related to our research are extracted from those papers and conclusion is made. The relevant articles were searched in six scientific databases such as IEEE Explore, ACM Digital Library, SpringerLink, Science Direct, Scopus, and Engineering Village. Furthermore, online survey was conducted based on the characteristics of CBRT approaches. This survey was conducted to validate the SLR result. Results: From the systematic Literature Review we have found out 8 different characteristics of CBRT approaches such as applicability, automation, complexity, behavior model used, coverage criteria, strength and weakness, theory used and input. We observe that these are the most important characteristics in CBRT approaches and these approaches should be considered in selecting or developing new CBRT approach. The results from the survey also validate our findings. From survey some more factors were identified. Conclusion: The research develops the state-of-art of CBRT approaches towards future research. The result of this thesis will be helpful for the researchers as well as practitioners who are working on CBRT. The result of the thesis can be considered as a basis for further study. Based on the result of this thesis further study can be done on making a framework based on these characteristics and support component based regression testing.

  • 268.
    Duong, Quang Trung
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    On the Performance Analysis of Cooperative Communications with Practical Constraints2012Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    With the rapid development of multimedia services, wireless communication engineers may face a major challenge to meet the demand of higher data-rate communication over error-prone mobile radio channels. As a promising solution, the concept of cooperative communication, where a so-called relay node is formed to assist the direct link, has recently been applied to alleviate the severe pathloss and shadowing effects in wireless systems. In addition, without spending extra spectrum and power resources, multiple-input multiple-output (MIMO) antenna systems have been shown to provide an immense improvement in system performance compared to its single-antenna counterpart. As such, cooperative MIMO communication is essential for wireless and mobile networks because of its remarkable increase in spectral efficiency and reliability. Although the utilization of cooperative communication in MIMO systems has gained great attention in the literature, most of the research works have assumed perfect conditions. Inspired by the aforementioned discussion, this thesis takes a step further to investigate the performance of cooperative communications with practical constraints. The thesis provides a general framework for performance analysis of cooperative communications subject to several practical constraints such as antenna correlation, rank-deficiency of the channel matrix, co-channel interference, and interference-limited constraint of cognitive radio networks based on an underlay spectrum-sharing approach. The thesis is divided into six parts. The first part investigates the performance of orthogonal space-time block codes (OSTBCs) over MIMO relay networks in Nakagami-m fading channels under the antenna correlation effect. The second part extends the full-rank MIMO channel to the case of the MIMO channel matrix being of rank-deficiency. Several important findings on the impact of the single-keyhole effect (SKE) and double-keyhole effect (DKE) are observed for two types of amplifying mechanism at the relay, namely, linear and squaring approaches. An important observation corroborated by our studies is that for offering a tradeoff between performance and complexity, we should use the linear approach for SKE and the squaring approach for DKE. The third part generalizes the keyhole effect to multi-keyhole channels. The exact and asymptotic expressions for symbol error probability (SEP) are derived for some specific cases such as multi-keyhole MIMO/multiple-input single-output (MISO) channel. The fourth part proposes a distributed Alamouti space-time code for two-way fixed gain amplify-and-forward (AF) relaying. In particular, closed-form expressions for approximated ergodic sum-rate and exact pairwise error probability (PWEP) are derived for Nakagami-m fading channels. To reveal further insights into array and diversity gains, an asymptotic PWEP is also obtained. The fifth part analyzes the outage performance of a two-way fixed gain AF relay system with beamforming, arbitrary antenna correlation, and co-channel interference (CCI). Finally, the sixth part investigates the impact of interference power constraint on the performance of cognitive relay networks based on the spectrum-sharing approach.

  • 269. Duong, Quang Trung
    et al.
    Bao, Vo Nguyen Quoc
    Alexandropoulos, George C.
    Zepernick, Hans-Jürgen
    Cooperative spectrum sharing networks with AF relay and selection diversity2011Ingår i: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 47, nr 20, s. 1149-1151Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The exact outage probability (OP) of cognitive dual-hop relay networks equipped with a single amplify-and-forward (AF) relay and a selection combining receiver at the destination is derived under spectrum sharing constraint on a primary user. The tractable closed-form OP readily enables evaluation of system performance, which indicates the significance of using a relay in cognitive radio networks with a spectrum sharing approach. The proposed analysis is validated by numerical examples.

  • 270.
    Duong, Quang Trung
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Bao, Vo Nguyen Quoc
    Tran, Hung
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Alexandropoulos, George C.
    Zepernick, Hans-Jürgen
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Effect of primary network on performance of spectrum sharing AF relaying2012Ingår i: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 48, nr 1, s. 25-U95Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Most of the research in spectrum sharing has neglected the effect of interference from primary users. In this reported work, the performance of spectrum sharing amplify-and-forward relay networks under interference-limited environment, where the interference induced by the transmission of primary networks is taken into account, is investigated. In particular, a closed-form expression tight lower bound of outage probability is derived. To reveal additional insights into the effect of primary networks on the diversity and array gains, an asymptotic expression is also obtained.

  • 271. Duong, Quang Trung
    et al.
    Bao, Vo Nguyen Quoc
    Zepernick, Hans-Jürgen
    Exact outage probability of cognitive AF relaying with underlay spectrum sharing2011Ingår i: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 47, nr 17, s. 1001-1002Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The exact closed-form expression for the outage probability (OP) of cognitive radio dual-hop amplify-and-forward (AF) relay networks is derived. The tractable expression of the OP, given in the form of elementary functions, readily enables evaluating the effect of primary users on the secondary system performance. It has been shown that the use of AF relaying significantly improves the performance of cognitive radio networks compared to its direct transmission counterpart.

  • 272.
    Duong, Quang Trung
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Costa, Daniel Benevides da
    Elkashlan, Maged
    Bao, Vo Nguyen Quoc
    Cognitive Amplify-and-Forward Relay Networks over Nakagami-m Fading2012Ingår i: IEEE Transactions on Vehicular Technology, ISSN 0018-9545, E-ISSN 1939-9359, Vol. 61, nr 5, s. 2368-2374Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this correspondence, the outage probability (OP) of dual-hop cognitive amplify-and-forward (AF) relay networks subject to independent non-identically distributed (i.n.i.d.) Nakagami-m fading is examined. We assume a spectrum sharing environment, where two different strategies are proposed for determining the transmit powers of the secondary network. Specifically, the transmit power conditions of the proposed spectrum sharing network are governed by either: (i) the combined power constraint of the interference on the primary network and maximum transmission power at the secondary network; or (ii) the single power constraint of the interference on the primary network. Closed-form lower bounds and asymptotic expressions for the OP are derived. Regardless of the transmit power constraint, we reveal that the diversity order is strictly defined by the minimum fading severity between the two hops of the secondary network. This aligns with the well-known result for conventional dual-hop AF relaying without spectrum sharing. Furthermore, the impact of the primary network on the diversity-multiplexing tradeoff is investigated. We confirm that the diversity-multiplexing tradeoff is independent of the primary network.

  • 273.
    Duong, Quang Trung
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    da Costa, Daniel Benevides
    Tsiftsis, Theodoros A.
    Zhong, Caijun
    Nallanathan, Arumugam
    Outage and Diversity of Cognitive Relaying Systems under Spectrum Sharing Environments in Nakagami-m Fading2012Ingår i: IEEE Communications Letters, ISSN 1089-7798, E-ISSN 1558-2558, Vol. 12, nr 11Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this letter, the outage performance of dualhop cooperative spectrum sharing systems with a direct link is investigated. A selection combining receiver is employed at the destination in order to combine the signals received from the decode-and-forward (DF) relay and from the source. Assuming independent non-identically distributed Nakagami-m fading channels, exact and asymptotic closed-form expressions are derived for the outage probability. Our results reveal that the diversity order of the considered system is solely determined by the fading severity parameters of the secondary network, being equal to min(m1, m2) + m0, where m0, m1, and m2 represent the fading severity parameters of the secondary nodes i.e., source→destination, source→relay, and relay→destination links, respectivel

  • 274.
    Duong, Quang Trung
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Kim, Kyeongjin
    Zepernick, Hans-Jürgen
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Tellambura, Chintha
    Opportunistic relaying for cognitive network with multiple primary users over Nakagami-m fading2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    The performance of cognitive spectrum sharing systems with opportunistic relay selection over Nakagami-m fading is analyzed in the presence of multiple primary users (PUs). In particular, we derive an exact closed-form expression for the outage probability (OP) of the considered cognitive relay systems under the joint impact of maximal transmit power Pt at secondary transmitter and peak interference power Ip at the primary user. Our general formulas cover several specific practical scenarios, e.g., where the maximal transmit power can be neglected compared to the peak interference power. In addition, a tractable expression for the asymptotic OP is also derived and reveals important insights into the system performance. We show that the number of PUs only affects the coding gain but not the diversity gain.

  • 275.
    Duong, Quang Trung
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Ngo, Hien Quoc
    Zepernick, Hans-Jürgen
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Nallanathan, Arumugam
    Distributed Space-Time Coding in Two-Way Fixed Gain Relay Networks over Nakagami-m Fading2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    The distributed Alamouti space-time code in two-way fixed gain amplify-and-forward (AF) relay is proposed in this paper. In particular, closed-form expressions for approximated ergodic sum-rate and exact pairwise error probability (PWEP) are derived for Nakagami-m fading channels. To reveal further insights into array and diversity gains, an asymptotic PWEP is also obtained. Finally, numerical results are provided to corroborate the proposed theoretical analysis.

  • 276.
    Duong, Quang Trung
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Shu, Lei
    Chen, Min
    Vo Nguyen Quoc, Bao
    Dac Binh, Ha
    Performance analysis of cooperative spatial multiplexing networks with AF/DF relaying and linear receiver over Rayleigh fading channels2015Ingår i: Wireless Communications & Mobile Computing, ISSN 1530-8669, E-ISSN 1530-8677, Vol. 15, nr 3, s. 500-509Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Cooperative spatial multiplexing (CSM) system has played an important role in wireless networks by offering a substantial improvement in multiplexing gain compared with its cooperative diversity counterpart. However, there is a limited number of research works that consider the performance of CSM systems. As such, in this paper, we have derived exact performance of CSM with amplify-and-forward and decode-and-forward relays in terms of outage capacity and ergodic capacity. We have shown that CSM systems yield a unity diversity order regardless of the number of antennas at the destination and the number of relays in the networks, which is the direct result of diversity and multiplexing gain trade-off. Our analytical expressions are corroborated by Monte-Carlo simulations.

  • 277.
    Duong, Quang Trung
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Suraweera, Himal A.
    Tsiftsis, Theodoros A.
    Zepernick, Hans-Jürgen
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Nallanathan, Arumugam
    Keyhole Effect in Dual-Hop MIMO AF Relay Transmission with Space-Time Block Codes2012Ingår i: IEEE Transactions on Communications, ISSN 0090-6778, E-ISSN 1558-0857, Vol. 60, nr 12, s. 1-11Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, the effect of keyhole on the performance of multiple-input multiple-output (MIMO) amplifyand-forward (AF) relay networks with orthogonal space-time block codes (OSTBCs) transmission is investigated. In particular, we analyze the asymptotic symbol error probability (SEP) performance of a downlink communication system where the amplifying processing at the relay can be implemented by either the linear or squaring approach. Our tractable asymptotic SEP expressions enable us to obtain both diversity and array gains. Our finding reveals that with condition nS > min(nR, nD), the linear approach can provide the full achievable diversity gain of min(nR, nD) when only the second hop suffers from the keyhole effect, i.e., single keyhole effect (SKE), where nS, nR, and nD are the number of antennas at source, relay, and destination, respectively. However, for the case that both the source-relay and relay-destination links experience the keyhole effect, i.e., double keyhole effect (DKE), the achievable diversity order is only one regardless of the number of antennas. In contrast, utilizing the squaring approach, the overall diversity gain can be achieved as min(nR, nD) for both SKE and DKE. An important observation corroborated by our studies is that for satisfying the tradeoff between performance and complexity, we should use the linear approach for SKE and the squaring approach for DKE.

  • 278. Duong, Quang Trung
    et al.
    Suraweera, Himal A.
    Tsiftsis, Theodoros A.
    Zepernick, Hans-Jürgen
    Nallanathan, Arumugam
    OSTBC Transmission in MIMO AF Relay Systems with Keyhole and Spatial Correlation Effects2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, we investigate the degenerative effects of antenna correlation and keyhole on the performance of multiple-input multiple-output (MIMO) amplify-and-forward (AF) relay networks. In particular, we considered a downlink MIMO AF relay system consisting of an nS-antenna base station S, an nR-antenna relay station R, and an nD-antenna mobile station D, in which the signal propagation originated from the mobile station suffers from keyhole and spatial correlation effects. We have derived an exact expression for the moment generation function of the instantaneous signal-to-noise ratio which enables us to analyze the symbol error probability and outage probability of the considered system.We have shown that although the mobile station is in a poor scattering environment, i.e., keyhole, the relay channel (S → R → D link) still achieves a cooperative diversity order of min(nR, nD) provided that the channel from the source (S → R link) is keyhole-free. This result is important to radio system designers since under such a severe scenario it is unnecessary to deploy a large number of antennas on the relay station (nR) but only requires nR = nD to obtain the maximum achievable diversity gain.

  • 279. Duong, Quang Trung
    et al.
    Suraweera, Himal A.
    Yuen, Chau
    Zepernick, Hans-Jürgen
    Multi-Keyhole Effect in MIMO AF Relay Downlink Transmission with Space-Time Block Codes2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    Multi-keyhole bridges the gap between single keyhole and full-scattering multiple-input multiple-output (MIMO) channels. In this paper, we therefore investigate the multi-keyhole effect on the MIMO amplify-and-forward (AF) relay downlink transmission with orthogonal space-time block codes. In particular, we derive the analytical symbol error rate (SER) expression for the considered system with arbitrary number of keyholes. Moreover, SER approximations in the high SNR regime for several important special scenarios of multi-keyhole channels are further derived. These asymptotic results provide important insights into the impact of system's parameters on the SER performance. Our analysis is confirmed by comparing with Monte-Carlo simulations.

  • 280.
    Duong, Quang Trung
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Suraweera, Himal A.
    Zepernick, Hans-Jürgen
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Yuen, Chau
    Beamforming in Two-Way Fixed Gain Amplify-and-Forward Relay Systems with CCI2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    We analyze the outage performance of a two-way fixed gain amplify-and-forward (AF) relay system with beamforming, arbitrary antenna correlation, and co-channel interference (CCI). Assuming CCI at the relay, we derive the exact individual user outage probability in closed-form. Additionally, while neglecting CCI, we also investigate the system outage probability of the considered network, which is declared if any of the two users is in transmission outage. Our results indicate that the position of the relay in this system plays an important role in determining the user as well as the system outage probability via such parameters as signal-to-noise imbalance, antenna configuration, spatial correlation, and CCI power. To render further insights into the effect of antenna correlation and CCI on the diversity and array gains, an asymptotic expression which tightly converges to exact results is also derived.

  • 281.
    Duong, Quang Trung
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Vo, Nguyen-Son
    Zepernick, Hans-Jürgen
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Shu, Lei
    Du, Xu
    Cheng, Wenping
    Replication Strategies for Video On-Demand over Wireless Mesh Networks: A Cross-Layer Optimization Approach2012Ingår i: Using Cross-Layer Techniques for Communication Systems / [ed] Rashvand, Habib F.; Kavian, Yousef S., IGI , 2012, s. 349-375Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    In this chapter, dependencies between the different protocol layers and across the hops through WMNs will be exploited to deliver video streaming with high QoE. Specifically, a cross-layer optimization approach is applied to a replication strategy for video on-demand over WMNs. Additionally, the authors consider a distributed implementation algorithm, namely Mod&Timer, to handle the placement of replicas for saving storage resources of the network. Simulation results are shown to demonstrate that the proposed cross-layer design outperforms many existing schemes in terms of QoE. More importantly, compared to other strategies without cross-layer interaction, the proposed cross-layer design satisfies the heterogeneous bandwidth constraint of end users.

  • 282.
    Duong, Quang Trung
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Zepernick, Hans-Jürgen
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Cross-Layer Design for Packet Data Transmission in Maximum Ratio Transmission Systems with Imperfect CSI and Co-Channel Interference2012Ingår i: Using Cross-Layer Techniques for Communication Systems / [ed] Rashvand, Habib F.; Kavian, Yousef S., IGI , 2012, s. 376-399Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    This chapter will therefore present some new results for the cross-layer design for packet data transmission applied to co-located MIMO with maximum ratio transmission. In this context, closed-form expressions for the average packet error rate, average achievable spectral efficiency, and outage probability are derived. This enables one to evaluate the performance of the cross-layer design under predetermined delay and packet loss constraints. Some important results in the high Signal-to-Noise Ratio (SNR) regime are also provided, revealing insights on how system and channel parameters affect system performance. More importantly, a mathematical analysis is proved to be a powerful tool to investigate the impact of practical issues such as channel estimation error, feedback delay, antenna correlation, and rank-deficient MIMO channel matrix, on the performance of cross-layer design.

  • 283. Duong, Quang Trung
    et al.
    Zepernick, Hans-Jürgen
    Tsiftsis, Theodoros A.
    Bao, Vo Nguyen Quoc
    Amplify-and-Forward MIMO Relaying with OSTBC over Nakagami-m Fading Channels2010Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, we analyze the performance of dual-hop channel state information (CSI)-assisted amplify-andforward (AF) cooperative networks using orthogonal space-time block codes (OSTBCs) over independent but not identically distributed Nakagami-m fading channels. Specifically, we present closed-form expressions of the outage probability (OP) and the symbol error probability (SEP). The analytical results are given in tractable forms which readily allow us to assess the performance of AF relay systems using OSTBCs. For sufficiently large signal-to-noise ratio, we obtain the asymptotic results for OP and SEP which reveal insights into the effect of fading factors on the diversity and coding gains. It has been shown that between the two hops the more severe link solely determines the diversity and coding gains. In particular, these two gains strictly depend on the fading severity parameters and the channel mean powers of the more rigorous hop, respectively. Numerical results are provided showing an excellent agreement between our analytical results and those of Monte-Carlo simulations for selected scenarios.

  • 284.
    Duong, Trung Quang
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Duy, Tran Trung
    Matthaiou, Michail
    Tsiftsis, Theodoros
    Karagiannidis, George K.
    Cognitive Cooperative Networks in Dual-Hop Asymmetric Fading Channels2013Ingår i: 2013 IEEE GLOBAL COMMUNICATIONS CONFERENCE (GLOBECOM), 2013, s. 955-961Konferensbidrag (Refereegranskat)
    Abstract [en]

    Previous works on cognitive relay networks (CRNs) considered only symmetric fading channels. However, in practical wireless propagation scenarios, it is likely that the channels of the secondary user (SU) and primary user (PU) may undergo different fading characteristics. In this paper, we assume that the channels of the secondary network (SU-source -> SU-relay -> SU-destination) are subject to Rician fading, whereas the channels of the link from the SU to the PU experience Rayleigh fading. Based on this framework, the end-to-end outage probability (OP) of CRNs is investigated for two different relaying schemes: i) in the absence of the direct link with decode-and-forward (DF) protocol and ii) in the presence of the direct link with incremental DF protocol. In particular, we derive both exact and asymptotic OP expressions for the considered CRNs. Our analysis reveals important insights into the impact of fading parameters on the CRN performance under distinct fading distributions.

  • 285.
    Dursjö, Louise
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Ett gränssnitt blir till, design och implementation av ett grafiskt gränssnitt med inriktning interaktionsdesign och grafik2011Självständigt arbete på grundnivå (kandidatexamen)Studentuppsats (Examensarbete)
    Abstract [sv]

    Gränssnitt finns överallt i vår vardag. Du finner dem i hemmet, i biblioteket, i affären, på tågstationen och till och med i din ficka. Hur kan utvecklingen av ett gränssnitt se ut och vad kan göras för att effektivisera utvecklingen? Ett gränssnitt kan alltid utvecklas och bli bättre. En gräns måste emellertid sättas för när gränssnittet är redo att komma ut på marknaden. När ska denna gräns sättas? I uppsatsen analyseras utvecklingen av ett gränssnitt från dess begynnelse fram till första leverans till kund. Utvecklingen av gränssnittet sker iterativt och delleveranser sker till kunden. För att kontrollera gränssnittets användbarhet testas gränssnittet av potentiella användare. Därefter analyseras testerna och utifrån dem presenteras sedan en sista version. De slutsatser som kunde dras är bland annat att det är bra att så fort som möjligt ta reda på av vilka systemet kommer användas och hur det kommer användas. Det är också bra att ge en känsla av hur systemet kommer fungera redan innan implementationen finns tillgänglig för att på så sätt effektivisera utvecklingen och undvika missförstånd.

  • 286. Dyba, Tore
    et al.
    Prikladnicki, Rafael
    Rönkkö, Kari
    Seaman, Carolyn
    Sillito, Jonathan
    Qualitative research in software engineering2011Ingår i: Empirical Software Engineering, ISSN 1382-3256 , Vol. 16, nr 4, s. 425-429Artikel i tidskrift (Refereegranskat)
  • 287. Dzamashvili-Fogelström, Nina
    Understanding and supporting requirements engineering decisions in market-driven software product development2010Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Context: Requirements engineering (RE) for software products offered to a mass market is concerned with deciding which of the diverse and large amounts of potential requirements to implement into future releases of a product. While being the key for achieving success, these decisions are very complex. Therefore, the need for decision support is well acknowledged. However, despite a growing body of research in this area, software companies are still experiencing problems in making informed decisions on which requirements to include in the software, or knowing how to maximize the potential ROI of a software release. Objective: The purpose of this thesis is to provide an increased understanding of how better decisions regarding the content of software products can be achieved. The research addresses two currently unresolved areas: balancing investments in different requirement types (commercial requirements, internal quality aspects and innovations) and identifying reasonable requirement analysis effort for informed requirements selection decisions. In order to address these areas the thesis focuses on investigating: 1) how uncertainty in the value proposition of a requirement is influencing the balance between investments in different requirement types; and 2) challenges and opportunities introduced by agile practices to RE decisions. Method: The presented research has an exploratory character and consists of empirical studies conducted both in industrial and academic settings. Results: The results include findings from an academic experiment and an industrial case study indicating that commercial requirements will be preferred over innovations and internal quality aspects. This is because innovations and internal quality aspects are associated with higher uncertainty in their value offering compared to commercial requirements and thereby are perceived to have higher level of business risk. The thesis also offers findings from an industrial case study, showing a misalignment between agile principles and the ability to take informed release planning decisions. Further, a framework (NORM) for finding an appropriate balance between information needs of RE decisions and requirements analysis effort is suggested. Conclusions: Uncertainty associated with the value proposition of different requirement types influences the requirements selection decisions, resulting in a dominance of commercial requirements. Thus, in order to achieve a better balance between investments in commercial requirements, internal quality and innovation it is important that uncertainty in the value offering of requirements is explicitly managed by methods providing support for RE decisions in a market-driven context. Agile methods provide opportunities to minimize overhead caused by excessive analysis of requirements, however adopting agile approaches in their current form pose challenges for performing product management and taking informed RE decisions in a market-driven context. Therefore, a balance between agility and information needs of RE decisions must be found. In combination, the thesis results offer a new insight and form a ground for defining improved approaches for supporting requirement selection decisions.

  • 288. Dzamashvili-Fogelström, Nina
    et al.
    Barney, Sebastian
    Aurum, Aybüke
    Hederstierna, Anders
    When Product Managers Gamble with Requirements: Attitudes to Value and Risk2009Konferensbidrag (Refereegranskat)
    Abstract [en]

    Context and motivation: Finding a balance between commercial (customer specific, market pull and external quality requirements) and internal quality requirements is a recognized challenge in market driven software product development (MDSPD). In order to address this challenge it is important to understand the preferences and biases influencing decision makers selecting requirements for software releases. Question/problem: Prospect theory has been successfully applied to many disciplines. Applying it to MDSPD suggests decision makers will avoid risk when selecting between commercial requirements, take risk with internal quality requirements, and prefer commercial requirements over internal quality requirements in order to maximize their perceived value. This paper seeks to investigate this claim. Principal ideas/results: This paper presents an experiment investigating whether the biases proposed by prospect theory can be seen operating in MDSPD requirements engineering (RE). The results indicate risk avoidance when dealing commercial requirements, while greater risk is taken when dealing with internal quality requirements. Contribution: As this is the first paper to use prospect theory to explain requirements selection decisions, it presents opportunity to educate people in the biases they bring to the RE process, and facilitate the creation of strategies for balancing the different requirements types.

  • 289. Dzamashvili-Fogelström, Nina
    et al.
    Gorschek, Tony
    Svahnberg, Mikael
    Olsson, PeO
    The Impact of Agile Principles on Market-Driven Software Product Development2010Ingår i: Software Process: Improvement and Practice, ISSN 1077-4866, E-ISSN 1099-1670, Vol. 22, nr 1, s. 53-80Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Agile development methods such as XP, SCRUM, Lean Software Development and others have gained much popularity during the last years. Agile methodologies promise faster time-to-market, satisfied customers and high quality software. While these prospects are appealing, the suitability of agile practices to different domains and business contexts still remains unclear. In this paper we investigate the applicability of agile principles in the context of market-driven software product development (MDPD), focusing on pre-project activities. This paper presents results of a comparison between typical properties of agile methods to the needs of MDPD, as well as findings of a case study conducted at Ericsson, an early adopter of agile product development. The results show misalignment between the agile principles and needs of pre-project activities in market-driven development. This misalignment threatens to subtract from the positive aspects of agile development, but maybe more importantly, threaten the overall product development by disabling effective product management.

  • 290. Dzamashvili-Fogelström, Nina
    et al.
    Numminen, Emil
    Barney, Sebastian
    Using Portfolio Theory to Support Requirements Selection Decisions2010Konferensbidrag (Refereegranskat)
    Abstract [en]

    Abstract—Selecting requirements for a release of software is a difficult undertaking as people have trouble comparing requirements of different types and have natural biases towards short-terms gains over longer-term sustainability. Portfolio theory is proposed as a solution to this problem, as it provides a method for balancing investment options to maximize the likelihood of a given return. This approach is explored generally and through an example. The results suggest portfolio theory can be applied for this purpose. Applying portfolio theory to determine the amount of development time that should be spent on different types of requirements shows the most potential, especially when data on expected risks and returns is limited.

  • 291. Dzamashvili-Fogelström, Nina
    et al.
    Svahnberg, Mikael
    Gorschek, Tony
    Investigating impact of business risk on requirements selection decisions2009Konferensbidrag (Refereegranskat)
    Abstract [en]

    In market-driven software product development, requirements that can potentially go into a product or a product release represent different kinds of investments. Requirements differ in the type of value that they provide and level of risk associated to investing in them. In this paper we investigate how business risk associated with different requirement types is considered by the decision makers and how it affects requirement selection decisions. The results of the conducted case study indicate that due to lacking methods for handling the requirements business risk, requirements with low level of risk are preferred over other type of requirements such as innovations and architectural improvements.

  • 292.
    Dąbrowski, Piotr Władysław
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Implementing augmented reality for visualisation of virtual buildings using Android2011Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [sv]

    The augmented reality represents one of the most current approach in implementing the artificial reality. Primarily required large extensive head-mounted-displays now follows the trend of minimising the necessary equipment. The study shows how is it done that a single mobile phone can be used as a device creating a new reality and also answers what calculations are required by such a system setting the augmented environment. Also a problem of mobile phone’s augmented reality systems accuracy is developed in reference to the commonly proclaimed 2-metres inaccuracy of the GPS device.

  • 293. Edison, Henry
    et al.
    bin Ali, Nauman
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Torkar, Richard
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Towards innovation measurement in the software industry2013Ingår i: Journal of Systems and Software, ISSN 0164-1212, Vol. 86, nr 5, s. 1390-1407Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In today's highly competitive business environments with shortened product and technology life cycle, it is critical for software industry to continuously innovate. This goal can be achieved by developing a better understanding and control of the activities and determinants of innovation. Innovation measurement initiatives assess innovation capability, output and performance to help develop such an understanding. This study explores various aspects relevant to innovation measurement ranging from definitions, measurement frameworks and metrics that have been proposed in literature and used in practice. A systematic literature review followed by an online questionnaire and interviews with practitioners and academics were employed to identify a comprehensive definition of innovation that can be used in software industry. The metrics for the evaluation of determinants, inputs, outputs and performance were also aggregated and categorised. Based on these findings, a conceptual model of the key measurable elements of innovation was constructed from the findings of the systematic review. The model was further refined after feedback from academia and industry through interviews.

  • 294. Egger, Sebastian
    et al.
    Hossfeld, Tobias
    Schatz, Raimund
    Fiedler, Markus
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Waiting times in quality of experience for web based services2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    A considerable share of applications such as web or e-mail browsing, online picture viewing and file downloads imply waiting times for their users, which is due to the turn-taking of information requests by the user and correspoding response times until each request is fulfilled. Thus, end-user quality perception in the context of interactive data services is dominated by waiting times; the longer the latter, the less satisfied the user becomes. As opposed to heavily researched multimedia experience, perception of waiting times is still not strongly explored in the context of Quality of Experience (QoE). This tutorial will contribute to closing this gap. In its first part, it addresses perception principles and discusses their applicability towards fundamental relationships between waiting times and resulting QoE. It then investigates to which extent the same relationships can also be used to describe QoE for more complex services such as web browsing. Finally, it discusses applications where waiting times determine QoE, amongst other factors. For example, the past shift from UDP media streaming to TCP media streaming (e.g. youtube.com) has extended the relevance of waiting times also to the domain of online video services. In particular, user-perceived quality suffers from initial delays when applications are launched, as well as from freezes during the delivery of the stream. These aspects, which have to be traded against each other to some extent, will be discussed mainly for HTTP video streaming in the last part of this tutorial.

  • 295. Egorova, E
    et al.
    Torchiano, M
    Morisio, M
    Wohlin, Claes
    Aurum, Aybüke
    Svensson, Richard Berntsson
    Stakeholders´ Perception of Success: An Empirical Investigation2009Konferensbidrag (Refereegranskat)
    Abstract [en]

    Different stakeholders involved in the software development may attribute success to different indicators. Analogously they may support different factors considered the root of successful projects. The study presented in this paper explores how different stakeholders perceive project success and what they deem the effect of specific factors on the project outcome. The study highlighted both commonalities and differences among three main stakeholder classes. A substantial agreement was observed concerning the characteristics that make a project or product successful. As far as the factors that could lead to success are concerned, more bias emerged.

  • 296.
    Ehsanibenafati, Aida
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Visualization Tool for Sensor Data Fusion2013Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    In recent years researchers has focused on the development of techniques for multi-sensor data fusion systems. Data fusion systems process data from multiple sensors to develop improved estimate of the position, velocity, attributes and identity of entities such as the targets or entities of interest. Visualizing sensor data from fused data to raw data from each sensor help analysts to interpret the data and assess sensor data fusion platform, an evolving situation or threats. Immersive visualization has emerged as an ideal solution for exploration of sensor data and provides opportunities for improvement in multi sensor data fusion. The thesis aims to investigate possibilities of applying information visualization to sensor data fusion platform in Volvo. A visualization prototype is also developed to enables multiple users to interactively visualize Sensor Data Fusion platform in real-time, mainly in order to demonstrates, evaluate and analyze the platform functionality. In this industrial study two research methodologies were used; a case study and an experiment for evaluating the results. First a case study was conducted in order to find the best visualization technique for visualizing sensor data fusion platform. Second an experiment was conducted to evaluate the usability of the prototype that has been developed and make sure the user requirement were met. The visualization tool enabled us to study the effectiveness and efficiency of the visualization techniques used. The results confirm that the visualization method used is effective, efficient for visualizing sensor data fusion platform.

  • 297.
    Ekelin, Annelie
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    To Be or Not to Be Active: Exploring Practices of eParticipation2006Ingår i: Electronic Government, Berlin: Springer Berlin / Heidelberg , 2006, s. 107-118Kapitel i bok, del av antologi (Övrigt vetenskapligt)
    Abstract [en]

    This chapter discusses the interplay of participation and non-participation within institutional and public practices of electronically mediated policy-making in the local public sector. The aim is to contribute to practice-based development of situated theoretical conceptualisation in the research domain. Applying a dialectical analysis, including also examples and processes of dissociation detected in ethnographic studies of actual use and design of these technologies, suggests a re-specification of the conceptual basis of eParticipation.

  • 298. Ekelin, Annelie
    et al.
    Anderberg, Peter
    Reddy, Kishore
    The Augment Project: Co-Constructive Mapping and Support of Accessibility and Participation2010Ingår i: Lecture Notes in Computer Science, Springer Verlag , 2010, Vol. 6229/2010, s. 95-103Konferensbidrag (Refereegranskat)
    Abstract [sv]

    Detta paper presenterades vid The Second International Conference on e-Participation, e-Part 2010, i Lausanne, Switzerland, Sept. 2010 och beskriver ett pågående forsknings- och utvecklingsprojekt; Augment-projektet. Bidraget presenterar bland annat arbetet med proof-of-concept utveckling samt diskuterar och problematiserar distinktionen mellan användargenererad information och användarskapat innehåll.

  • 299. Ekelin, Annelie
    et al.
    Eriksén, Sara
    Aktiv på egna eller andras villkor – hur blir man delaktig?2010Ingår i: Förvaltning och medborgarskap i förändring / [ed] Lindblad-Gidlund, Katarina; Ekelin, Annelie; Eriksén, Sara; Ranerup, Agneta, Lund: Studentlitteratur , 2010, s. 47-65Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [sv]

    The aim of this book is to contribute to the development of a dialogue between ongoing research and established practice in the area of e-administration. Just as established practice consists of many different established pratices within the public sector , researchers who are interested and involved in the area of e-administration also represents a number of different perspectives and academic disciplines. This chapter is about development of e-participation as a part of e-government. The chapter discusses how active citizenship is co-constructed and shaped. Questions about how active citizenship is matched by "active politicianship" and active civil servant-ship are raised besides questions about what it means to become an active citize. Is it for example possible to become active by being deliberatively inactive in certain administrative processes? The discussion is based on combined development work and research in several projects within public sector.

  • 300. Ekelin, Annelie
    et al.
    Eriksén, Sara
    Does user participation matter in the design and development of e-participation tools? Experiences from a proof-of-concept project2011Konferensbidrag (Refereegranskat)
    Abstract [sv]

    Detta paper presenterar erfarenheter från utveckling av proof-of-concept avseende en mobil tillgänglighetstjänst; Augment. Samarbete mellan flera parter (stakeholders) analyseras utifrån participatory design (PD) eller kollaborativ design approach. Diskussion om svårigheter och möjligheter att kombinera PD med ansatser till "open innovation" och användning av sociala media utifrån användares behov och krav avseende användardriven utveckling av verktyg för e-deltagande. Hur möter man krav på användare on-demand kontra utvecklare on-demand ? Och hur kan detta kombineras med traditionella systemutvecklingsmetoder?

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