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  • 51.
    Jalili, Leilia
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Parichehreh, Ali
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Alfredsson, Stefan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Garcia, Johan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Brunström, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Efficient traffic offloading for seamless connectivity in 5G networks onboard high speed trains2017In: IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC, IEEE, 2017, p. 1-6Conference paper (Refereed)
    Abstract [en]

    Seamless wireless connectivity in high mobility scenarios (≥ 300 km/h), is one of the fundamental key requirements for the future 5G networks. High speed train (HST) is one of the preferred mid-range transportation systems, and highlights the challenges of providing wireless connectivity in high mobility scenarios for the 5G networks. Advanced version of Long Term Evolution (LTE-A) from the Third Generation Partnership Project (3GPP) with peak data rate up to 100 Mbps in high mobility scenarios paved the road toward high quality and cost effective onboard Internet in HSTs. However, frequent handovers (HO) of large number of onboard users increase the service interruptions that in turn inevitably decrease the experienced quality of service (QoS). In this paper, according to the two-tier architecture of the HST wireless connectivity, we propose a novel and practically viable onboard traffic offloading mechanism among the HST carriages that effectively mitigates the service interruptions caused by frequent HOs of massive number of onboard users. The proposed architecture does not imply any change on the LTE network standardization. Conclusions are supported by numerical results for realistic LTE parameters and current HST settings.

  • 52. Jordan, Howell
    et al.
    Rosik, Jacek
    Herold, Sebastian
    Clausthal University of Technology.
    Botterweck, Goetz
    Buckley, Jim
    Manually Locating Features in Industrial Source Code: The Search Actions of Software Nomads2015In: 2015 IEEE 23rd International Conference on Program Comprehension, IEEE, 2015Conference paper (Refereed)
  • 53.
    Knodel, Jens
    et al.
    Fraunhofer IESE, Germany.
    Buckley, Jim
    Lero, University of Limerick, Ireland.
    Herold, Sebastian
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    The need for an open corpus of software architecture descriptions2017In: 19. Workshop Software-Reengineering und -Evolution: 8. Workshop "Design for Future", Bad-Honnef: Gesellschaft für Informatik, 2017, p. 25-26Conference paper (Refereed)
    Abstract [en]

    Software architectures are the conceptual tool to share information about key aspects of a software system and to enable reasoning about the principal, most fundamental, and often most difficult-to-change design decisions of the system. Studies of failed software systems give evidence that architecture drift, erosion or degradation is a prevalent problem in industrial practice. But a recent systematic literature review [9] indicates that research currently investigates compliance checking or inconsistency detection only. To advance research we need an open and grounded corpus of software architecture description – serving as a basis for more sophisticated studies beyond detection only. Such a corpus could enable (1) to evaluate new approaches, (2) to provide means for fixing degradation (when it occurs or a-posteriori), (3) to compare and benchmark approaches and, ultimately, (4) enable longitudinal studies in the field.

  • 54.
    Kolb, Stefan
    et al.
    University of Bamberg.
    Lenhard, Jörg
    University of Bamberg.
    Wirtz, Guido
    University of Bamberg.
    Application Migration Effort in the Cloud2015In: Services Transactions on Cloud Computing, ISSN 2326-7542, E-ISSN 2326-7550, Vol. 3, no 4, p. 1-15Article in journal (Refereed)
    Abstract [en]

    Over the last years, the utilization of cloud resources has been steadily rising and an increasing number of enterprises are moving applications to the cloud. A leading trend is the adoption of Platform as a Service to support rapid application deployment. By providing a managed environment, cloud platforms take away a lot of complex configuration effort required to build scalable applications. However, application migrations to and between clouds cost development effort and open up new risks of vendor lock-in. This is problematic because frequent migrations may be necessary in the dynamic and fast changing cloud market. So far, the effort of application migration in PaaS environments and typical issues experienced in this task are hardly understood. To improve this situation, we present a cloud-to-cloud migration of a real-world application to seven representative cloud platforms. In this case study, we analyze the feasibility of the migrations in terms of portability and the effort of the migrations. We present a Dockerbased deployment system that provides the ability of isolated and reproducible measurements of deployments to platform vendors, thus enabling the comparison of platforms for a particular application. Using this system, the study identifies key problems during migrations and quantifies these differences by distinctive metrics

  • 55.
    Kolb, Stefan
    et al.
    University of Bamberg.
    Lenhard, Jörg
    University of Bamberg.
    Wirtz, Guido
    University of Bamberg.
    Application Migration Effort in the Cloud: The Case of Cloud Platforms2015In: 2015 IEEE 8TH INTERNATIONAL CONFERENCE ON CLOUD COMPUTING / [ed] Pu, C; Mohindra, A, IEEE, 2015, Vol. 3, no 4, p. 1-15Conference paper (Refereed)
  • 56.
    Kolb, Stefan
    et al.
    University of Bamberg.
    Lenhard, Jörg
    University of Bamberg.
    Wirtz, Guido
    University of Bamberg.
    Bridging the Heterogeneity of Orchestrations - A Petri Net-based Integration of BPEL and Windows Workflow2012In: 5th IEEE International Conference on Service-Oriented Computing and Applications, IEEE conference proceedings, 2012Conference paper (Refereed)
    Abstract [en]

    Service orchestrations are a powerful tool for implementing intra- and interorganizational business processes that base on services. Several heterogeneous orchestration languages can be found in contemporary IT landscapes. While the Web Services Business Process Execution Language (BPEL) is the de facto standard, others gain attention, including Windows Workflow (WF) in the. NET segment. When integrating orchestrations, incompatibilities between them can easily arise. In this paper, we investigate an automated Petri net-based integration between BPEL and WF to solve these issues with behavioral adapter services. We provide a mapping of WF to Open Workflow Nets (oWFNs) and implement it in a compiler. Thereby, we integrate our approach with existing approaches for BPEL and adapter synthesis and validate the integration with a standards-based case study using the two languages.

  • 57.
    Kopp, Oliver
    et al.
    University of Stuttgart.
    Lenhard, JörgKarlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).Pautasso, CesareUSI Lugano.
    Proceedings of the 9th Central European Workshop on Services and their Composition (ZEUS 2017)2017Conference proceedings (editor) (Refereed)
  • 58. Körner, Marco
    et al.
    Herold, Sebastian
    Clausthal University of Technology.
    Rausch, Andreas
    Composition of applications based on software product lines using architecture fragments and component sets2014In: WICSA '14 Companion Proceedings of the WICSA 2014: Companion Volume, Association for Computing Machinery (ACM), 2014Conference paper (Refereed)
  • 59. Körtgen, A. -T
    et al.
    Becker, S. M.
    Herold, Sebastian
    Clausthal University of Technology.
    A graph-based framework for rapid construction of document integration tools2007In: Journal of Integrated Design & Process Science, ISSN 1092-0617, E-ISSN 1875-8959, Vol. 11, no 4, p. 19-39Article in journal (Refereed)
  • 60. Körtgen, Anne-Thérèse
    et al.
    Becker, Simon M.
    Herold, Sebastian
    Clausthal University of Technology.
    A Graph-Based Framework For Rapid Construction Of Document Integration Tools2007In: Journal of Integrated Design & Process Science, ISSN 1092-0617, E-ISSN 1875-8959, Vol. 11, no 4, p. 19-39Article in journal (Refereed)
  • 61.
    Lenhard, Jörg
    University of Bamberg.
    A Pattern-based Analysis of WS-BPEL and Windows Workflow2011Report (Other academic)
  • 62.
    Lenhard, Jörg
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013). Karlstad University.
    Improving Process Portability Through Metrics and Continuous Inspection2017In: Advances in Intelligent Process-Aware Information Systems / [ed] Manfred Reichert, Roy Oberhauser, Gregor Grambow, Springer, 2017, p. 193-223Chapter in book (Refereed)
  • 63.
    Lenhard, Jörg
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    On the Suitability of Process Model Similarity Metrics for Evaluating Replaceability2016In: Proceedings of the 10th Advanced Summer School on Service Oriented Computing / [ed] Johanna Barzen , Rania Khalaf , Frank Leymann , Bernhard Mitschang, Cambridge, MA, USA, 2016, Vol. 10, p. 1-15Conference paper (Refereed)
  • 64.
    Lenhard, Jörg
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Portability of executable service-oriented processes: Metrics and validation2016In: Service Oriented Computing and Applications, ISSN 1863-2386, E-ISSN 1863-2394, p. 1-21Article in journal (Refereed)
    Abstract [en]

    A key promise of process languages based on open standards, such as the Web Services Business Process Execution Language, is the avoidance of vendor lock-in through the portability of processes among runtime environments. Despite the fact that today various runtimes claim to support this language, every runtime implements a different subset, thus hampering portability and locking in their users. It is our intention to improve this situation by enabling the measurement of the portability of executable service-oriented processes. This helps developers to assess their implementations and to decide if it is feasible to invest in the effort of porting a process to another runtime. In this paper, we define several software quality metrics that quantify the degree of portability of an executable, service-oriented process from different viewpoints. When integrated into a development environment, such metrics can help to improve the portability of the outcome. We validate the metrics theoretically with respect to measurement theory and construct validity using two validation frameworks. The validation is complemented with an empirical evaluation of the metrics using a large set of processes coming from several process libraries.

  • 65.
    Lenhard, Jörg
    University of Bamberg.
    Portability of Process-Aware and Service-Oriented Software: Evidence and Metrics2016Doctoral thesis, monograph (Other academic)
  • 66.
    Lenhard, Jörg
    University of Bamberg.
    Towards Quantifying the Adaptability of Executable BPMN Processes2014Conference paper (Refereed)
  • 67.
    Lenhard, Jörg
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Ferme, Vincenzo
    Software Institute, Faculty of Informatics, USI Lugano, Switzerland.
    Harrer, Simon
    University of Bamberg, Germany.
    Geiger, Matthias
    University of Bamberg, Germany.
    Pautasso, Cesare
    Software Institute, Faculty of Informatics, USI Lugano, Switzerland.
    Lessons Learned from Evaluating Workflow Management Systems2017In: Service-Oriented Computing – ICSOC 2017 Workshops / [ed] L. Braubach, J.M. Murillo, N. Kaviani, M. Lama, L. Burgueño, N. Moha & M. Oriol, Springer, 2017, p. 215-227Conference paper (Refereed)
    Abstract [en]

    Work ow Management Systems (WfMSs) today act as ser- vice composition engines and service-oriented middleware to enable the execution of automated business processes. Automation based on WfMSs promises to enable the model-driven construction of exible and easily maintainable services with high-performance characteristics. In the past decade, signi cant e ort has been invested into standardizing WfMSs that compose services, with standards such as the Web Services Business Process Execution Language (WS-BPEL) or the Business Process Model and Notation (BPMN). One of the aims of standardization is to enable users of WfMSs to compare di erent systems and to avoid vendor lock-in. Despite these e orts, there are many expectations concerning portabil- ity, performance e ciency, usability, reliability and maintainability of WfMSs that are likely to be unful lled. In this work, we synthesize the ndings of two research initiatives that deal with WfMSs conformance and performance benchmarking to distill a set of lessons learned and best practices. These ndings provide useful advice for practitioners who plan to evaluate and use WfMSs and for WfMS vendors that would like to foster wider adoption of process-centric service composition middleware. 

  • 68.
    Lenhard, Jörg
    et al.
    University of Bamberg.
    Geiger, Matthias
    University of Bamberg.
    Wirtz, Guido
    University of Bamberg.
    On the Measurement of Design-Time Adaptability for Process-Based Systems2015In: 2015 IEEE Symposium on Service-Oriented System Engineering, IEEE, 2015, p. 1-10Conference paper (Refereed)
  • 69.
    Lenhard, Jörg
    et al.
    University of Bamberg.
    Harrer, Simon
    University of Bamberg.
    Wirtz, Guido
    University of Bamberg.
    Measuring the Installability of Service Orchestrations Using the SQuaRE Method2013In: Service-Oriented Computing and Applications (SOCA), 2013 IEEE 6th International Conference on, IEEE Press, 2013, p. 118-125Conference paper (Refereed)
    Abstract [en]

    Service-oriented software consists of middleware, such as application servers and runtime engines, into which service applications are deployed. This middleware is often complex and difficult to install. The deployment of services requires the crafting of deployment descriptors and packaging of applications. As a consequence, the installation of service-oriented software systems can be a daunting task. Install ability, however, is an important influencer of the portability of software. Portability in turn is one of the main goals of service orchestration languages based on open standards. In this paper, we investigate the install ability of service orchestrations based on the Systems and software Quality Requirements and Evaluation (Square) method, the new series of software quality standards currently under development by the ISO/IEC. We develop a measurement framework based on Square and tailored to evaluating the install ability of service orchestrations and their runtimes. We validate the measurement framework theoretically and show its applicability in a case study.

  • 70.
    Lenhard, Jörg
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013). Karlstad University.
    Hassan, Mohammad Mahdi
    Blom, Martin
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013). Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Herold, Sebastian
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Are Code Smell Detection Tools Suitable For Detecting Architecture Degradation?2017In: ECSA '17 Proceedings of the 11th European Conference on Software Architecture: Companion Proceedings, Association for Computing Machinery (ACM), 2017, p. 138-144Conference paper (Refereed)
    Abstract [en]

    Context: Several studies suggest that there is a relation between code smells and architecture degradation. They claim that classes, which have degraded architecture-wise, can be detected on the basis of code smells, at least if these are manually identiÿed in the source code.

    Objective: To evaluate the suitability of contemporary code smell detection tools by combining different smell categories for ÿnding classes that show symptoms of architecture degradation.

    Method: A case study is performed in which architectural in-consistencies in an open source system are detected via reflexion modeling and code smell metrics are collected through several tools. Using data mining techniques, we investigate if it is possible to auto-matically and accurately classify classes connected to architectural inconsistencies based on the gathered code smell data.

    Results: Results suggest that existing code smell detection techniques, as implemented in contemporary tools, are not sufficiently accurate for classifying whether a class contains architectural in-consistencies, even when combining categories of code smells.

    Conclusion: It seems that current automated code smell detection techniques require ÿne-tuning for a speciÿc system if they are to be used for ÿnding classes with architectural inconsistencies. More research on architecture violation causes is needed to build more accurate detection techniques that work out-of-the-box.

  • 71.
    Lenhard, Jörg
    et al.
    University of Bamberg.
    Schönberger, Andreas
    Wirtz, Guido
    University of Bamberg.
    Edit Distance-Based Pattern Support Assessment of Orchestration Languages2011In: On the Move to Meaningful Internet Systems: OTM 2011, Springer Berlin/Heidelberg, 2011, p. 137-154Conference paper (Refereed)
    Abstract [en]

    Orchestration languages are of paramount importance when implementing business processes based on services. Several languages for specifying Web Services-based orchestrations are available today. Examples are the Web Services Business Process Execution Language or Windows Workflow. Patterns for process-aware information systems have frequently been used to assess such languages. Various studies discuss the degree of support such languages provide for certain sets of patterns. However, the traditional trivalent support measure is limited in terms of granularity and selectivity. This paper proposes an edit distance complexity measure that allows to overcome these issues. The applicability of this measure is demonstrated by an analysis of several orchestration languages using four different pattern catalogs.

  • 72.
    Lenhard, Jörg
    et al.
    University of Bamberg.
    Schönberger, Andreas
    Wirtz, Guido
    University of Bamberg.
    Streamlining Pattern Support Assessment for Service Composition Languages2011In: Services und ihre Komposition: Proceedings of the 3rd Central-European Workshop on Services and their Composition / [ed] Daniel Eichhorn, Agnes Koschmider, Huayu Zhang, CEUR-WS.org , 2011, Vol. 705, p. 112-119Conference paper (Refereed)
  • 73.
    Lenhard, Jörg
    et al.
    University of Bamberg.
    Wirtz, Guido
    University of Bamberg.
    Building Orchestrations in B2Bi: The Case of BPEL 2.0 BPMN 2.02012In: / [ed] Andreas Schönberger, Oliver Kopp, Niels Lohmann, 2012, p. 58-65Conference paper (Refereed)
    Abstract [en]

    Various approaches for service-oriented business-to-business integration (B2Bi) rely on a top-down development methodology. The starting point is a choreography model which is subsequently partitioned into multiple orchestrations. Most current approaches use the Web Services Business Process Execution Language (BPEL) for implementing the latter. At the same time, a plethora of other languages, such as Business Process Model and Notation (BPMN) 2.0 process diagrams, is available. As integration partners are free to select the orchestration language of their choice, it should be easy to integrate different orchestration languages with current choreography technology. Language transformation, starting from a suitable format, is a means to achieve this. In this paper, we assess BPEL 2.0 and BPMN 2.0 process diagrams for their suitability for this transformation in a services-based B2Bi setting using a requirements framework identified through a literature study.

  • 74.
    Lenhard, Jörg
    et al.
    University of Bamberg.
    Wirtz, Guido
    University of Bamberg.
    Detecting Portability Issues in Model-Driven BPEL Mappings2013Conference paper (Refereed)
    Abstract [en]

    Service orchestration languages, like the Web Services Business Process Execution Language (BPEL), have been frequently used to provide an implementation platform for model-driven development approaches. As avoidance of vendor lock-in and portability of process definitions are central aims of BPEL, most approaches claim to support a large set of different runtime environments. But, even though today various runtimes for BPEL are available, every runtime implements a different language subset, thus hampering portability. Our idea is to improve this situation by using techniques, the Web Services Interoperability Organization (WS-I) has used to improve services interoperability. We describe a portability profile for BPEL that can detect portability issues in process definitions. Using this profile, we evaluate the portability of BPEL mappings used in several model-driven development approaches.

  • 75.
    Lenhard, Jörg
    et al.
    University of Bamberg.
    Wirtz, Guido
    University of Bamberg.
    Measuring the Portability of Executable Service-Oriented Processes2013Conference paper (Refereed)
    Abstract [en]

    A key promise of process languages based on open standards, such as the Web Services Business Process Execution Language, is the avoidance of vendor lock-in through the portability of process definitions among runtime environments. Despite the fact that today, various runtimes claim to support this language, every runtime implements a different subset, thus hampering portability and locking in their users. In this paper, we intend to improve this situation by enabling the measurement of the degree of portability of process definitions. This helps developers to assess their process definitions and to decide if it is feasible to invest in the effort of porting a process definition to another runtime. We define several software quality metrics that quantify the degree of portability a process definition provides from different viewpoints. We validate these metrics theoretically with two validation frameworks and empirically with a large set of process definitions coming from several process libraries.

  • 76. Mair, Matthias
    et al.
    Herold, Sebastian
    Clausthal University of Technology.
    Towards Extensive Software Architecture Erosion Repairs2013In: Software Architecture: 7th European Conference, ECSA 2013, Montpellier, France, July 1-5, 2013. Proceedings / [ed] Drira, Khalil, Springer , 2013, p. 299-306Conference paper (Other academic)
  • 77. Mair, Matthias
    et al.
    Herold, Sebastian
    Clausthal University of Technology.
    Rausch, Andreas
    Towards flexible automated software architecture erosion diagnosis and treatment2014In: WICSA '14 Companion Proceedings of the WICSA 2014: Companion Volume, Association for Computing Machinery (ACM), 2014Conference paper (Refereed)
  • 78. Mensing, Benjamin
    et al.
    Goltz, Ursula
    Aniculaesei, Adina
    Herold, Sebastian
    Clausthal University of Technology.
    Rausch, Andreas
    Gartner, Stefan
    Schneider, Kurt
    Towards integrated rule-driven software development for IT ecosystems2012In: 2012 6th IEEE International Conference on Digital Ecosystems and Technologies (DEST), IEEE, 2012Conference paper (Refereed)
  • 79.
    Nasim, Robayet
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Diameter Single Sign On – Secureand Personalized Service Provision via Authenticationand Authorization Mechanisms2012In: Advances in Computer Science and Information Technology. Networks and Communications: Second International Conference, CCSIT 2012, Bangalore, India, January 2-4, 2012. Proceedings, Part I, Berlin: Springer Berlin/Heidelberg, 2012, p. 573-581Chapter in book (Refereed)
    Abstract [en]

    Network Services universally rely upon Authentication and Authorization mechanisms to ensure secure and personalized service provision. Protocols, such as Diameter provides a reliable framework for efficient accesscontrol to network services utilized by network devices. This framework canalso encompass application level services e.g. web applications accessed viaweb browsers [1]. On the other hand, the prevalence of Internet based servicesand applications have brought about the burden of identity managementamong distributed security domains, an issue not specifically addressed byprotocols such as Diameter. Efforts such as OpenID alleviate this difficulty byproposing an application level framework based on open standards to realizesingle sign on/off [ 2 ]semantics with regard to application level services. However, these technologies do not build upon existing security infrastructure, require significant investment in terms of technology adoption and have yet to receive industry wide acceptance and support. This paper presents Diameter Single Sign On – a framework that provides single sign on/off semantics in the context of network and application level services by harnessing the strengths of existing and proven authentication and authorization infrastructure. Because of combination of the Diameter protocol with Single Sign On and OpenID the proposed architecture overcomes the problem of identity managementand also builds on existing security infrastructure.

  • 80.
    Papastergiou, Giorgos
    et al.
    Simula Research Laboratory, Norway.
    Fairhurst, Gorry
    University of Aberdeen, U.K.
    Ros, David
    Simula Research Laboratory, Norway.
    Brunström, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Grinnemo, Karl-Johan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013). Distributed Systems and Communication (DISCO).
    Hurtig, Per
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Khademi, Naeem
    University of Oslo, Norway.
    Tüxen, Michael
    Münster University of Applied Sciences, Steinfurt, Germany.
    Welzl, Michael
    University of Oslo, Norway.
    Damjanovic, Dragana
    Mozilla Corporation, Mountain View, CA, USA.
    Mangiante, Simone
    EMC Corporation, Ovens, Ireland.
    De-Ossifying the Internet Transport Layer: A Survey and Future Perspectives2017In: IEEE Communications Surveys and Tutorials, ISSN 1553-877X, E-ISSN 1553-877X, Vol. 19, no 1, p. 619-639Article in journal (Refereed)
    Abstract [en]

    It is widely recognized that the Internet transport layer has become ossified, where further evolution has become hard or even impossible. This is a direct consequence of the ubiquitous deployment of middleboxes that hamper the deployment of new transports, aggravated further by the limited flexibility of the application programming interface (API) typically presented to applications. To tackle this problem, a wide range of solutions have been proposed in the literature, each aiming to address a particular aspect. Yet, no single proposal has emerged that is able to enable evolution of the transport layer. In this paper, after an overview of the main issues and reasons for transport-layer ossification, we survey proposed solutions and discuss their potential and limitations. The survey is divided into five parts, each covering a set of point solutions for a different facet of the problem space: (1) designing middlebox-proof transports; (2) signaling for facilitating middlebox traversal; (3) enhancing the API between the applications and the transport layer; (4) discovering and exploiting end-to-end capabilities; and (5) enabling user-space protocol stacks. Based on this analysis, we then identify further development needs toward an overall solution. We argue that the development of a comprehensive transport layer framework, able to facilitate the integration and cooperation of specialized solutions in an application-independent and flexible way, is a necessary step toward making the Internet transport architecture truly evolvable. To this end, we identify the requirements for such a framework and provide insights for its development

  • 81.
    Pettersson Strömsjö, Lucas
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Digital besökslogg: Ett steg mot ett modernare kundbemötande2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Denna uppsats beskriver utvecklingen av en lösning vars syfte är att modernisera det bemötande som gäster får på uppdragsgivarens kontor. Lösningen består av en applikation som körs på en surfplatta, en applikation för administration av dess data samt en molnbaserad databas, där Entity Framework är en central del för att koppla samman dessa komponenter.När en gäst anländer får gästen registrera sig i applikationen på surfplattan och sedan får den anställde som ska ta emot gästen en mobilnotifikation. Notifikationen gör den anställde observant om gästens ankomst. För att identifiera gästen skrivs även en speciellt framtagen gästetikett ut där information från surfplatteapplikationen finns angiven.

  • 82. Rausch, Andreas
    et al.
    Bartelt, Christian
    Herold, Sebastian
    Clausthal University of Technology.
    Klus, Holger
    Niebuhr, Dirk
    From Software Systems to Complex Software Ecosystems: Model- and Constraint-Based Engineering of Ecosystems2013In: Perspectives on the Future of Software Engineering: Essays in Honor of Dieter Rombach Part I / [ed] Münch, J. & Schmidt, K., Springer, 2013, p. 61-80Chapter in book (Other academic)
  • 83. Rausch, Andreas
    et al.
    Muller, Jorg P.
    Niebuhr, Dirk
    Herold, Sebastian
    Clausthal University of Technology.
    Goltz, Ursula
    IT ecosystems: A new paradigm for engineering complex adaptive software systems2012In: 2012 6th IEEE International Conference on Digital Ecosystems and Technologies (DEST), IEEE, 2012Conference paper (Refereed)
  • 84.
    Santos, Ricardo
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Ogawa, Hiroaki
    Tokyo Institute of Technology.
    Khanh Tran, Gia
    Tokyo Institute of Technology.
    Sakaguchi, Kei
    Tokyo Institute of Technology.
    Kassler, Andreas
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013). Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Turning the knobs on OpenFlow-based resiliency in mmWave small cell meshed networks2017In: Globecom Workshops (GC Wkshps), 2017 IEEE: 5G Testbed, IEEE, 2017Conference paper (Refereed)
    Abstract [en]

    As a solution to cope with the increase of wireless network traffic for future 5G networks, the IEEE 802.11ad standard enables multi-gigabit connectivity within the 60 GHz spectrum. Since these networks typically have low range, a vast number of small cells is required to form a wireless backhaul that can be easily affected by temporary failures due to blockage/interference. Software-defined Networking (SDN) is a paradigm that allows the centralization of the control plane management, which can be applied to mmWave wireless backhaul networks. Using SDN enables the possibility of having resilience mechanisms in the network, such as Fast-Failover (FF) group tables in the OpenFlow (OF) protocol. In this paper, we analyse resilient forwarding configurations upon temporary link failures. We perform our evaluation on a 4 small cell testbed with multiple IEEE 802.11ad interfaces, showing how OF-based resiliency can be applied, through FF and the Bidirectional-Forwarding Detection (BFD) protocol. Our results show how BFD can be tuned to improve the link state monitoring, and how a local reactive failover mechanism can benefit ongoing traffic in small cell meshed backhaul networks.

  • 85.
    Scherner, Tobias
    et al.
    Goethe University.
    Fritsch, Lothar
    Goethe University.
    Technology Assurance2011In: Digital Privacy: Final report of the PRIME project / [ed] Camenisch, Jan; Leenes, Ronald; Sommer, Dieter, Heidelberg: Springer Berlin/Heidelberg, 2011Chapter in book (Refereed)
    Abstract [en]

    This chapter documents the experiences of assurance evaluation during the early stage of a large software development project. The PRIME project researches, contracts and integrates privacy-respecting software to business environments. There exist several approaches to ensure the quality of secure software. Some of these approaches have the focus of quality assurance at a very early stage of the development process and have weaknesses to ensure the quality of this process until the product is ready to enter the market. Other approaches, like the CC, focus on inspection, or more concrete evaluation, of ready-to-market products.

  • 86.
    Sinkala, Zipani Tom
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Blom, Martin
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013). Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Herold, Sebastian
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    A mapping study of software architecture recovery for software product lines2018In: Proceedings of the 12th European Conference on Software Architecture: Companion Proceedings, Madrid, Spain: Association for Computing Machinery (ACM), 2018, article id 49Conference paper (Refereed)
    Abstract [en]

    Migrating a family of software systems from ad-hoc development approaches such as `clone-and-own' towards software product lines (SPL) is a challenging task. Software architecture recovery techniques can play a crucial role in such a migration. However, it is to date still unclear how these techniques, which have been mostly developed for single system architecture recovery in mind, can be utilized in an SPL context most effectively. In this paper, we present a mapping study examining 35 research articles with the purpose of discussing the current state of the art in applying software architecture recovery techniques for SPL and identifying potential research gaps in this area. The results provide evidence that currently used approaches do not seem to consider the potential architectural degradation that might exist in the family of systems to be migrated. Moreover, it is hard to generalize across empirical studies as currently it seems difficult to compare and benchmark the approaches applied for software product line architecture (SPLA) extraction/reconstruction.

  • 87.
    Sundqvist, Christoffer
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Djuvfeldt, Joakim
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Digital Inlärningsportal: Ett mer intressant sätt att lära sig2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This essay describes the implementation of a websolution where gamification is applied. The purpose of the websolution is to create a more interesting platform where the focus is education and information sharing between the company's employees. The websolution have the possibility for administrators to create articles which can be linked to quizzes and such. The articles are shown on a newspage which is available for everyone employed at the company. Each article is linked with a quiz or such that the employees can do. To create a feeling of gamification the scores are stored and displayed onto a highscore board that is available to everyone. The essay also describes the design choices that have been done during the project. Some of the choices that are described are Application Programming Interface (APIlayer), frameworks, database models, data exchange, user management, visual design and security. The product that has been created will be presented both visually and functionally where the results are compared to what was asked by the employer. The essay ends with what the authors think went right or wrong with the implementation and design but also some things they learnt and how the project can be further developed.

  • 88.
    Svensson, Oskar
    Karlstad University, Faculty of Health, Science and Technology (starting 2013).
    En applikation som stöd till personer med neuropsykiatriska funktionsnedsättningar2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Neurodevelopmental disorders affect the way the brain handles information and can result in difficulties with concentration, shifting attention, memory and processing the surrounding environment. Clarifying pedagogy is a method that is used to support people with neurodevelopmental disorders.  Clarifying pedagogy aims to describe the environment and events clearly to the people with neurodevelopmental disorders. Aid included in clarifying pedagogy is schedules, checklist and time visualisations. This project is continuing the development of the Vardag-application for the company Altran. Vardag implements schedules in an application to help people with neurodevelopmental disorders. Vardag is implemented with React Native to make the application compatible with IOS and Android. A web API was developed and used to communicate between the application and the server.  During this project the features upload image, sub activities, visual themes and activities on a specific date was implemented.    

  • 89.
    Taheri, Javid
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Cho, Daewoong
    Univ. of Sydney, Sydney, NSW, Australia.
    Zomaya, Albert Y
    School of Information Technologies, University of Sydney.
    Real-Time Virtual Network Function (VNF) Migration toward Low Network Latency in Cloud Environments2017In: 2017 IEEE 10th International Conference on Cloud Computing (CLOUD), Piscataway: IEEE, 2017, p. 798-801Conference paper (Refereed)
    Abstract [en]

    Network Function Virtualization (NFV) is an emerging network architecture to increase flexibility and agility within operator's networks by placing virtualized services on demand in Cloud data centers (CDCs). One of the main challenges for the NFV environment is how to minimize network latency in the rapidly changing network environments. Although many researchers have already studied in the field of Virtual Machine (VM) migration and Virtual Network Function (VNF) placement for efficient resource management in CDCs, VNF migration problem for low network latency among VNFs has not been studied yet to the best of our knowledge. To address this issue in this article, we i) formulate the VNF migration problem and ii) develop a novel VNF migration algorithm called VNF Real-time Migration (VNF-RM) for lower network latency in dynamically changing resource availability. As a result of experiments, the effectiveness of our algorithm is demonstrated by reducing network latency by up to 70.90% after latency-aware VNF migrations.

  • 90.
    Voronkov, Artem
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Lindskog, Stefan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Martucci, Leonardo
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Challenges in Managing Firewalls2015In: Secure IT Systems: 20th Nordic Conference, NordSec 2015, Stockholm, Sweden, October 19–21, 2015, Proceedings, Springer, 2015, Vol. 9417, p. 191-196Conference paper (Refereed)
    Abstract [en]

    Firewalls are essential security devices that can provide protection against network attacks. To be effective, a firewall must be properly configured to ensure consistency with the security policy. However, configuring is a complex and error-prone process. This work tries to identify the reasons behind firewall misconfigurations. To achieve our goal, we conducted a series of semi-structured interviews with system administrators that manage access control lists in networks of different sizes. The paper discusses our interview results and describes future work.

  • 91.
    Wästlund, Erik
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Psychology. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT. Karlstad University, Faculty of Economic Sciences, Communication and IT, Service Research Center.
    Angulo, Julio
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Fischer-Hübner, Simone
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Evoking Comprehensive Mental Models of Anonymous Credentials2012In: Proceedings of the 2011 IFIP WG 11.4 international conference on Open Problems in Network Security / [ed] Camenisch J., Kesdogan, D., Berlin: Springer Berlin/Heidelberg, 2012, Vol. 7039, p. 1-14Conference paper (Refereed)
    Abstract [en]

    Anonymous credentials are a fundamental technology for preserving end users' privacy by enforcing data minimization for online applications. However, the design of user-friendly interfaces that convey their privacy benefits to users is still a major challenge. Users are still unfamiliar with the new and rather complex concept of anonymous credentials, since no obvious real-world analogies exists that can help them create the correct mental models. In this paper we explore different ways in which suitable mental models of the data minimization property of anonymous credentials can be evoked on end users. To achieve this, we investigate three different approaches in the context of an e-shopping scenario: a card-based approach, an attribute-based approach and an adapted card-based approach. Results show that the adapted card-based approach is a good approach towards evoking the right mental models for anonymous credential applications. However, better design paradigms are still needed to make users understand that attributes can be used to satisfy conditions without revealing the value of the attributes themselves.

  • 92.
    Zhang, Ge
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Fischer Hübner, Simone
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Peer-to-Peer VoIP Communications Using Anonymisation Overlay Networks2010In: Communications and Multimedia Security: Proceedings of the 11th IFIP TC 6/TC 11, CMS2010, international conference on Communications and Multimedia Security / [ed] De Decker, Bart; Schaumüller-Bichl, Ingrid, Berlin: Springer , 2010, p. 130-141Conference paper (Refereed)
    Abstract [en]

    Nowadays, Voice over Internet Protocol (VoIP) which enables voice conversation remotely over packet switched networks gains much attentions for its low costs and flexible services. However, VoIP calling anonymity, particularly to withhold who called whom, is difficult to achieve since VoIP infrastructures are usually deployed in an open networking environment (e.g., the Internet). Our work studies an anonymisation overlay network (AON) based solution to prevent surveillance from external attackers, who are able to wiretap the communication channels as well as to manipulate voice packets in the channels. However, it has been demonstrated that the VoIP combined with traditional AONs are vulnerable to two attacks, namely watermark attack and complementary matching attack. Taking these two attacks into account, we investigate the defensive dropping method in VoIP: A VoIP user-agent sends packets to an AON in a constant rate, but packets during periods of silence are marked. Then, the AON drops some silence packets and forwards the remaining ones to their destinations. The result of our experiments shows that the dropping rate must be carefully selected to counteract both of the two attacks. Finally, we discuss further threats in terms of this solution

  • 93.
    Zhang, Ge
    et al.
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Pallares, Jordi Jaen
    Rebahi, Yacine
    Fischer-Hübner, Simone
    Karlstad University, Division for Information Technology.
    SIP Proxies: New Reflectors in the Internet2010In: Communications and Multimedia Security: 11th IFIP TC 6/TC 11 International Conference, CMS 2010, Linz, Austria, May 31 – June 2, 2010. Proceedings, Springer, 2010, p. 142-153Conference paper (Refereed)
    Abstract [en]

    To mitigate identity theft in SIP networks, an inter-domain authentication mechanism based on certificates is proposed in RFC 4474 [10]. Unfortunately, the design of the certificate distribution in this mechanism yields some vulnerabilities. In this paper, we investigate an attack which exploits SIP infrastructures as reflectors to bring down a web server. Our experiments demonstrate that the attacks can be easily mounted. Finally, we discuss some potential methods to prevent this vulnerability.

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