@phdthesis{Tinnefeld2014,
  author    = {Tinnefeld, Christian},
  title     = {Building a columnar database on shared main memory-based storage},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-72063},
  school      = {Universit{\"a}t Potsdam},
  pages     = {175},
  year      = {2014},
  abstract  = {In the field of disk-based parallel database management systems exists a great variety of solutions based on a shared-storage or a shared-nothing architecture. In contrast, main memory-based parallel database management systems are dominated solely by the shared-nothing approach as it preserves the in-memory performance advantage by processing data locally on each server. We argue that this unilateral development is going to cease due to the combination of the following three trends: a) Nowadays network technology features remote direct memory access (RDMA) and narrows the performance gap between accessing main memory inside a server and of a remote server to and even below a single order of magnitude. b) Modern storage systems scale gracefully, are elastic, and provide high-availability. c) A modern storage system such as Stanford's RAMCloud even keeps all data resident in main memory. Exploiting these characteristics in the context of a main-memory parallel database management system is desirable. The advent of RDMA-enabled network technology makes the creation of a parallel main memory DBMS based on a shared-storage approach feasible. This thesis describes building a columnar database on shared main memory-based storage. The thesis discusses the resulting architecture (Part I), the implications on query processing (Part II), and presents an evaluation of the resulting solution in terms of performance, high-availability, and elasticity (Part III). In our architecture, we use Stanford's RAMCloud as shared-storage, and the self-designed and developed in-memory AnalyticsDB as relational query processor on top. AnalyticsDB encapsulates data access and operator execution via an interface which allows seamless switching between local and remote main memory, while RAMCloud provides not only storage capacity, but also processing power. Combining both aspects allows pushing-down the execution of database operators into the storage system. We describe how the columnar data processed by AnalyticsDB is mapped to RAMCloud's key-value data model and how the performance advantages of columnar data storage can be preserved. The combination of fast network technology and the possibility to execute database operators in the storage system opens the discussion for site selection. We construct a system model that allows the estimation of operator execution costs in terms of network transfer, data processed in memory, and wall time. This can be used for database operators that work on one relation at a time - such as a scan or materialize operation - to discuss the site selection problem (data pull vs. operator push). Since a database query translates to the execution of several database operators, it is possible that the optimal site selection varies per operator. For the execution of a database operator that works on two (or more) relations at a time, such as a join, the system model is enriched by additional factors such as the chosen algorithm (e.g. Grace- vs. Distributed Block Nested Loop Join vs. Cyclo-Join), the data partitioning of the respective relations, and their overlapping as well as the allowed resource allocation. We present an evaluation on a cluster with 60 nodes where all nodes are connected via RDMA-enabled network equipment. We show that query processing performance is about 2.4x slower if everything is done via the data pull operator execution strategy (i.e. RAMCloud is being used only for data access) and about 27\% slower if operator execution is also supported inside RAMCloud (in comparison to operating only on main memory inside a server without any network communication at all). The fast-crash recovery feature of RAMCloud can be leveraged to provide high-availability, e.g. a server crash during query execution only delays the query response for about one second. Our solution is elastic in a way that it can adapt to changing workloads a) within seconds, b) without interruption of the ongoing query processing, and c) without manual intervention.},
  language  = {en}
}
@phdthesis{Hebig2014,
  author    = {Hebig, Regina},
  title     = {Evolution of model-driven engineering settings in practice},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-70761},
  school      = {Universit{\"a}t Potsdam},
  year      = {2014},
  abstract  = {Nowadays, software systems are getting more and more complex. To tackle this challenge most diverse techniques, such as design patterns, service oriented architectures (SOA), software development processes, and model-driven engineering (MDE), are used to improve productivity, while time to market and quality of the products stay stable. Multiple of these techniques are used in parallel to profit from their benefits. While the use of sophisticated software development processes is standard, today, MDE is just adopted in practice. However, research has shown that the application of MDE is not always successful. It is not fully understood when advantages of MDE can be used and to what degree MDE can also be disadvantageous for productivity. Further, when combining different techniques that aim to affect the same factor (e.g. productivity) the question arises whether these techniques really complement each other or, in contrast, compensate their effects. Due to that, there is the concrete question how MDE and other techniques, such as software development process, are interrelated. Both aspects (advantages and disadvantages for productivity as well as the interrelation to other techniques) need to be understood to identify risks relating to the productivity impact of MDE. Before studying MDE's impact on productivity, it is necessary to investigate the range of validity that can be reached for the results. This includes two questions. First, there is the question whether MDE's impact on productivity is similar for all approaches of adopting MDE in practice. Second, there is the question whether MDE's impact on productivity for an approach of using MDE in practice remains stable over time. The answers for both questions are crucial for handling risks of MDE, but also for the design of future studies on MDE success. This thesis addresses these questions with the goal to support adoption of MDE in future. To enable a differentiated discussion about MDE, the term MDE setting'' is introduced. MDE setting refers to the applied technical setting, i.e. the employed manual and automated activities, artifacts, languages, and tools. An MDE setting's possible impact on productivity is studied with a focus on changeability and the interrelation to software development processes. This is done by introducing a taxonomy of changeability concerns that might be affected by an MDE setting. Further, three MDE traits are identified and it is studied for which manifestations of these MDE traits software development processes are impacted. To enable the assessment and evaluation of an MDE setting's impacts, the Software Manufacture Model language is introduced. This is a process modeling language that allows to reason about how relations between (modeling) artifacts (e.g. models or code files) change during application of manual or automated development activities. On that basis, risk analysis techniques are provided. These techniques allow identifying changeability risks and assessing the manifestations of the MDE traits (and with it an MDE setting's impact on software development processes). To address the range of validity, MDE settings from practice and their evolution histories were capture in context of this thesis. First, this data is used to show that MDE settings cover the whole spectrum concerning their impact on changeability or interrelation to software development processes. Neither it is seldom that MDE settings are neutral for processes nor is it seldom that MDE settings have impact on processes. Similarly, the impact on changeability differs relevantly. Second, a taxonomy of evolution of MDE settings is introduced. In that context it is discussed to what extent different types of changes on an MDE setting can influence this MDE setting's impact on changeability and the interrelation to processes. The category of structural evolution, which can change these characteristics of an MDE setting, is identified. The captured MDE settings from practice are used to show that structural evolution exists and is common. In addition, some examples of structural evolution steps are collected that actually led to a change in the characteristics of the respective MDE settings. Two implications are: First, the assessed diversity of MDE settings evaluates the need for the analysis techniques that shall be presented in this thesis. Second, evolution is one explanation for the diversity of MDE settings in practice. To summarize, this thesis studies the nature and evolution of MDE settings in practice. As a result support for the adoption of MDE settings is provided in form of techniques for the identification of risks relating to productivity impacts.},
  language  = {en}
}
@phdthesis{Truemper2014,
  author    = {Tr{\"u}mper, Jonas},
  title     = {Visualization techniques for the analysis of software behavior and related structures},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-72145},
  school      = {Universit{\"a}t Potsdam},
  year      = {2014},
  abstract  = {Software maintenance encompasses any changes made to a software system after its initial deployment and is thereby one of the key phases in the typical software-engineering lifecycle. In software maintenance, we primarily need to understand structural and behavioral aspects, which are difficult to obtain, e.g., by code reading. Software analysis is therefore a vital tool for maintaining these systems: It provides - the preferably automated - means to extract and evaluate information from their artifacts such as software structure, runtime behavior, and related processes. However, such analysis typically results in massive raw data, so that even experienced engineers face difficulties directly examining, assessing, and understanding these data. Among other things, they require tools with which to explore the data if no clear question can be formulated beforehand. For this, software analysis and visualization provide its users with powerful interactive means. These enable the automation of tasks and, particularly, the acquisition of valuable and actionable insights into the raw data. For instance, one means for exploring runtime behavior is trace visualization. This thesis aims at extending and improving the tool set for visual software analysis by concentrating on several open challenges in the fields of dynamic and static analysis of software systems. This work develops a series of concepts and tools for the exploratory visualization of the respective data to support users in finding and retrieving information on the system artifacts concerned. This is a difficult task, due to the lack of appropriate visualization metaphors; in particular, the visualization of complex runtime behavior poses various questions and challenges of both a technical and conceptual nature. This work focuses on a set of visualization techniques for visually representing control-flow related aspects of software traces from shared-memory software systems: A trace-visualization concept based on icicle plots aids in understanding both single-threaded as well as multi-threaded runtime behavior on the function level. The concept's extensibility further allows the visualization and analysis of specific aspects of multi-threading such as synchronization, the correlation of such traces with data from static software analysis, and a comparison between traces. Moreover, complementary techniques for simultaneously analyzing system structures and the evolution of related attributes are proposed. These aim at facilitating long-term planning of software architecture and supporting management decisions in software projects by extensions to the circular-bundle-view technique: An extension to 3-dimensional space allows for the use of additional variables simultaneously; interaction techniques allow for the modification of structures in a visual manner. The concepts and techniques presented here are generic and, as such, can be applied beyond software analysis for the visualization of similarly structured data. The techniques' practicability is demonstrated by several qualitative studies using subject data from industry-scale software systems. The studies provide initial evidence that the techniques' application yields useful insights into the subject data and its interrelationships in several scenarios.},
  language  = {en}
}
@misc{Wallenta2014,
  author    = {Wallenta, Daniel},
  title     = {A Lefschetz fixed point formula for elliptic quasicomplexes},
  series = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe},
  number    = {885},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-43547},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-435471},
  pages     = {577 -- 587},
  year      = {2014},
  abstract  = {In a recent paper, the Lefschetz number for endomorphisms (modulo trace class operators) of sequences of trace class curvature was introduced. We show that this is a well defined, canonical extension of the classical Lefschetz number and establish the homotopy invariance of this number. Moreover, we apply the results to show that the Lefschetz fixed point formula holds for geometric quasiendomorphisms of elliptic quasicomplexes.},
  language  = {en}
}
@misc{BoeckmannOsterloh2014,
  author    = {B{\"o}ckmann, Christine and Osterloh, Lukas},
  title     = {Runge-Kutta type regularization method for inversion of spheroidal particle distribution from limited optical data},
  series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {907},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-44120},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-441200},
  pages     = {150 -- 165},
  year      = {2014},
  abstract  = {The Runge-Kutta type regularization method was recently proposed as a potent tool for the iterative solution of nonlinear ill-posed problems. In this paper we analyze the applicability of this regularization method for solving inverse problems arising in atmospheric remote sensing, particularly for the retrieval of spheroidal particle distribution. Our numerical simulations reveal that the Runge-Kutta type regularization method is able to retrieve two-dimensional particle distributions using optical backscatter and extinction coefficient profiles, as well as depolarization information.},
  language  = {en}
}
@phdthesis{Fudickar2014,
  author    = {Fudickar, Sebastian},
  title     = {Sub Ghz transceiver for indoor localisation of smartphones},
  school      = {Universit{\"a}t Potsdam},
  pages     = {IV, 167},
  year      = {2014},
  language  = {en}
}
@phdthesis{Schacht2014,
  author    = {Schacht, Alexander},
  title     = {Konzepte und Strategien mobiler Plattformen zur Erfassung und Anlayse von Vitalparametern in heterogenen Telemonotoring-Systemen},
  pages     = {215},
  year      = {2014},
  language  = {de}
}
@article{LamprechtMargariaSteffen2014,
  author    = {Lamprecht, Anna-Lena and Margaria, Tiziana and Steffen, Bernhard},
  title     = {Modeling and Execution of Scientific Workflows with the jABC Framework},
  series = {Process Design for Natural Scientists: an agile model-driven approach},
  journal   = {Process Design for Natural Scientists: an agile model-driven approach},
  number    = {500},
  editor    = {Lambrecht, Anna-Lena and Margaria, Tiziana},
  publisher = {Springer Verlag},
  address   = {Berlin},
  isbn      = {978-3-662-45005-5},
  issn      = {1865-0929},
  pages     = {14 -- 29},
  year      = {2014},
  abstract  = {We summarize here the main characteristics and features of the jABC framework, used in the case studies as a graphical tool for modeling scientific processes and workflows. As a comprehensive environment for service-oriented modeling and design according to the XMDD (eXtreme Model-Driven Design) paradigm, the jABC offers much more than the pure modeling capability. Associated technologies and plugins provide in fact means for a rich variety of supporting functionality, such as remote service integration, taxonomical service classification, model execution, model verification, model synthesis, and model compilation. We describe here in short both the essential jABC features and the service integration philosophy followed in the environment. In our work over the last years we have seen that this kind of service definition and provisioning platform has the potential to become a core technology in interdisciplinary service orchestration and technology transfer: Domain experts, like scientists not specially trained in computer science, directly define complex service orchestrations as process models and use efficient and complex domain-specific tools in a simple and intuitive way.},
  language  = {en}
}
@article{LamprechtMargaria2014,
  author    = {Lamprecht, Anna-Lena and Margaria, Tiziana},
  title     = {Scientific Workflows and XMDD},
  series = {Process Design for Natural Scientists: an agile model-driven approach},
  journal   = {Process Design for Natural Scientists: an agile model-driven approach},
  number    = {500},
  editor    = {Lambrecht, Anna-Lena and Margaria, Tiziana},
  publisher = {Springer Verlag},
  address   = {Berlin},
  isbn      = {978-3-662-45005-5},
  issn      = {1865-0929},
  pages     = {1 -- 13},
  year      = {2014},
  abstract  = {A major part of the scientific experiments that are carried out today requires thorough computational support. While database and algorithm providers face the problem of bundling resources to create and sustain powerful computation nodes, the users have to deal with combining sets of (remote) services into specific data analysis and transformation processes. Today's attention to "big data" amplifies the issues of size, heterogeneity, and process-level diversity/integration. In the last decade, especially workflow-based approaches to deal with these processes have enjoyed great popularity. This book concerns a particularly agile and model-driven approach to manage scientific workflows that is based on the XMDD paradigm. In this chapter we explain the scope and purpose of the book, briefly describe the concepts and technologies of the XMDD paradigm, explain the principal differences to related approaches, and outline the structure of the book.},
  language  = {en}
}
@article{LamprechtWickertMargaria2014,
  author    = {Lamprecht, Anna-Lena and Wickert, Alexander and Margaria, Tiziana},
  title     = {Lessons Learned},
  series = {Process Design for Natural Scientists: an agile model-driven approach},
  journal   = {Process Design for Natural Scientists: an agile model-driven approach},
  number    = {500},
  editor    = {Lambrecht, Anna-Lena and Margaria, Tiziana},
  publisher = {Springer Verlag},
  address   = {Berlin},
  isbn      = {978-3-662-45005-5},
  issn      = {1865-0929},
  pages     = {45 -- 64},
  year      = {2014},
  abstract  = {This chapter summarizes the experience and the lessons we learned concerning the application of the jABC as a framework for design and execution of scientific workflows. It reports experiences from the domain modeling (especially service integration) and workflow design phases and evaluates the resulting models statistically with respect to the SIB library and hierarchy levels.},
  language  = {en}
}
@article{LamprechtWickert2014,
  author    = {Lamprecht, Anna-Lena and Wickert, Alexander},
  title     = {The Course's SIB Libraries},
  series = {Process Design for Natural Scientists: an agile model-driven approach},
  journal   = {Process Design for Natural Scientists: an agile model-driven approach},
  number    = {500},
  editor    = {Lambrecht, Anna-Lena and Margaria, Tiziana},
  publisher = {Springer Verlag},
  address   = {Berlin},
  isbn      = {978-3-662-45005-5},
  issn      = {1865-0929},
  pages     = {30 -- 44},
  year      = {2014},
  abstract  = {This chapter gives a detailed description of the service framework underlying all the example projects that form the foundation of this book. It describes the different SIB libraries that we made available for the course "Process modeling in the natural sciences" to provide the functionality that was required for the envisaged applications. The students used these SIB libraries to realize their projects.},
  language  = {en}
}
@book{OPUS4-8627,
  title     = {HPI Future SOC Lab},
  editor    = {Meinel, Christoph and Polze, Andreas and Oswald, Gerhard and Strotmann, Rolf and Seibold, Ulrich and Schulzki, Bernhard},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-86271},
  publisher      = {Universit{\"a}t Potsdam},
  pages     = {vi, 250},
  year      = {2014},
  abstract  = {Das Future SOC Lab am HPI ist eine Kooperation des Hasso-Plattner-Instituts mit verschiedenen Industriepartnern. Seine Aufgabe ist die Erm{\"o}glichung und F{\"o}rderung des Austausches zwischen Forschungsgemeinschaft und Industrie. Am Lab wird interessierten Wissenschaftlern eine Infrastruktur von neuester Hard- und Software kostenfrei f{\"u}r Forschungszwecke zur Verf{\"u}gung gestellt. Dazu z{\"a}hlen teilweise noch nicht am Markt verf{\"u}gbare Technologien, die im normalen Hochschulbereich in der Regel nicht zu finanzieren w{\"a}ren, bspw. Server mit bis zu 64 Cores und 2 TB Hauptspeicher. Diese Angebote richten sich insbesondere an Wissenschaftler in den Gebieten Informatik und Wirtschaftsinformatik. Einige der Schwerpunkte sind Cloud Computing, Parallelisierung und In-Memory Technologien. In diesem Technischen Bericht werden die Ergebnisse der Forschungsprojekte des Jahres 2014 vorgestellt. Ausgew{\"a}hlte Projekte stellten ihre Ergebnisse am 9. April 2014 und 29. Oktober 2014 im Rahmen der Future SOC Lab Tag Veranstaltungen vor.},
  language  = {en}
}
@book{OPUS4-6982,
  title     = {HPI Future SOC Lab},
  number    = {88},
  editor    = {Meinel, Christoph and Polze, Andreas and Oswald, Gerhard and Strotmann, Rolf and Seibold, Ulrich and Schulzki, Bernard},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  isbn      = {978-3-86956-282-7},
  issn      = {1613-5652},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-68195},
  publisher      = {Universit{\"a}t Potsdam},
  pages     = {iii, 174},
  year      = {2014},
  abstract  = {The "HPI Future SOC Lab" is a cooperation of the Hasso-Plattner-Institut (HPI) and industrial partners. Its mission is to enable and promote exchange and interaction between the research community and the industrial partners. The HPI Future SOC Lab provides researchers with free of charge access to a complete infrastructure of state of the art hard- and software. This infrastructure includes components, which might be too expensive for an ordinary research environment, such as servers with up to 64 cores. The offerings address researchers particularly from but not limited to the areas of computer science and business information systems. Main areas of research include cloud computing, parallelization, and In-Memory technologies. This technical report presents results of research projects executed in 2013. Selected projects have presented their results on April 10th and September 24th 2013 at the Future SOC Lab Day events.},
  language  = {en}
}
@book{MeinelSchnjakinMetzkeetal.2014,
  author    = {Meinel, Christoph and Schnjakin, Maxim and Metzke, Tobias and Freitag, Markus},
  title     = {Anbieter von Cloud Speicherdiensten im {\"U}berblick},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  isbn      = {978-3-86956-274-2},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-68780},
  publisher      = {Universit{\"a}t Potsdam},
  pages     = {84},
  year      = {2014},
  abstract  = {Durch die immer st{\"a}rker werdende Flut an digitalen Informationen basieren immer mehr Anwendungen auf der Nutzung von kosteng{\"u}nstigen Cloud Storage Diensten. Die Anzahl der Anbieter, die diese Dienste zur Verf{\"u}gung stellen, hat sich in den letzten Jahren deutlich erh{\"o}ht. Um den passenden Anbieter f{\"u}r eine Anwendung zu finden, m{\"u}ssen verschiedene Kriterien individuell ber{\"u}cksichtigt werden. In der vorliegenden Studie wird eine Auswahl an Anbietern etablierter Basic Storage Diensten vorgestellt und miteinander verglichen. F{\"u}r die Gegen{\"u}berstellung werden Kriterien extrahiert, welche bei jedem der untersuchten Anbieter anwendbar sind und somit eine m{\"o}glichst objektive Beurteilung erlauben. Hierzu geh{\"o}ren unter anderem Kosten, Recht, Sicherheit, Leistungsf{\"a}higkeit sowie bereitgestellte Schnittstellen. Die vorgestellten Kriterien k{\"o}nnen genutzt werden, um Cloud Storage Anbieter bez{\"u}glich eines konkreten Anwendungsfalles zu bewerten.},
  language  = {de}
}
@book{MeinelWillems2014,
  author    = {Meinel, Christoph and Willems, Christian},
  title     = {openHPI : 哈索•普拉特纳研究院的 MOOC（大规模公开在线课）计划},
  number    = {89},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  isbn      = {978-3-86956-291-9},
  issn      = {1613-5652},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-70380},
  publisher      = {Universit{\"a}t Potsdam},
  pages     = {22},
  year      = {2014},
  abstract  = {摘要。哈索•普拉特纳研究院 (HPI) 的新型互动在线教育平台 openHPI (https://openHPI.de) 可以为从事信息技术和信息学领域内容的工作和感兴趣的学员提供可自由访问的、免费的在线课程。与斯坦福大学于 2011 年首推，之后也在美国其他精英大学提供的"网络公开群众课"（简称 MOOC）一样，openHPI 同样在互联网中提供学习视频和阅读材料，其中综合了支持学习的自我测试、家庭作业和社交讨论论坛，并刺激对促进学习的虚拟学习团队的培训。与"传统的"讲座平台，比如 tele-TASK 平台 (http://www.tele-task.de) 不同（在该平台中，可调用以多媒体方式记录的和已准备好的讲座），openHPI 提供的是按教学法准备的在线课程。这些课程的开始时间固定，之后在连续六个课程周稳定的提供以多媒体方式准备的、尽可能可以互动的学习材料。每周讲解课程主题的一章。为此在该周开始前会准备一系列学习视频、文字、自我测试和家庭作业材料，课程学员在该周将精力用于处理这些内容。这些计划与一个社交讨论平台相结合，学员在该平台上可以与课程导师和其他学员交换意见、解答问题和讨论更多主题。当然，学员可以自己决定学习活动的类型和范围。他们可以为课程作出自己的贡献，比如在论坛中引用博文或推文。之后其他学员可以评论、讨论或自己扩展这些博文或推文。这样学员、教师和提供的学习内容就在一个虚拟的团体中与社交学习网络相互结合起来。},
  language  = {de}
}
@book{MeinelPlattnerDoellneretal.2014,
  author    = {Meinel, Christoph and Plattner, Hasso and D{\"o}llner, J{\"u}rgen Roland Friedrich and Weske, Mathias and Polze, Andreas and Hirschfeld, Robert and Naumann, Felix and Giese, Holger and Baudisch, Patrick},
  title     = {Proceedings of the 7th Ph.D. Retreat of the HPI Research School on Service-oriented Systems Engineering},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  isbn      = {978-3-86956-273-5},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-63490},
  publisher      = {Universit{\"a}t Potsdam},
  pages     = {ii, 218},
  year      = {2014},
  abstract  = {Design and Implementation of service-oriented architectures imposes a huge number of research questions from the fields of software engineering, system analysis and modeling, adaptability, and application integration. Component orientation and web services are two approaches for design and realization of complex web-based system. Both approaches allow for dynamic application adaptation as well as integration of enterprise application. Commonly used technologies, such as J2EE and .NET, form de facto standards for the realization of complex distributed systems. Evolution of component systems has lead to web services and service-based architectures. This has been manifested in a multitude of industry standards and initiatives such as XML, WSDL UDDI, SOAP, etc. All these achievements lead to a new and promising paradigm in IT systems engineering which proposes to design complex software solutions as collaboration of contractually defined software services. Service-Oriented Systems Engineering represents a symbiosis of best practices in object-orientation, component-based development, distributed computing, and business process management. It provides integration of business and IT concerns. The annual Ph.D. Retreat of the Research School provides each member the opportunity to present his/her current state of their research and to give an outline of a prospective Ph.D. thesis. Due to the interdisciplinary structure of the Research Scholl, this technical report covers a wide range of research topics. These include but are not limited to: Self-Adaptive Service-Oriented Systems, Operating System Support for Service-Oriented Systems, Architecture and Modeling of Service-Oriented Systems, Adaptive Process Management, Services Composition and Workflow Planning, Security Engineering of Service-Based IT Systems, Quantitative Analysis and Optimization of Service-Oriented Systems, Service-Oriented Systems in 3D Computer Graphics sowie Service-Oriented Geoinformatics.},
  language  = {en}
}
@phdthesis{Schnjakin2014,
  author    = {Schnjakin, Maxim},
  title     = {Cloud-RAID},
  pages     = {137},
  year      = {2014},
  language  = {de}
}
@phdthesis{Abedjan2014,
  author    = {Abedjan, Ziawasch},
  title     = {Improving RDF data with data mining},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-71334},
  school      = {Universit{\"a}t Potsdam},
  year      = {2014},
  abstract  = {Linked Open Data (LOD) comprises very many and often large public data sets and knowledge bases. Those datasets are mostly presented in the RDF triple structure of subject, predicate, and object, where each triple represents a statement or fact. Unfortunately, the heterogeneity of available open data requires significant integration steps before it can be used in applications. Meta information, such as ontological definitions and exact range definitions of predicates, are desirable and ideally provided by an ontology. However in the context of LOD, ontologies are often incomplete or simply not available. Thus, it is useful to automatically generate meta information, such as ontological dependencies, range definitions, and topical classifications. Association rule mining, which was originally applied for sales analysis on transactional databases, is a promising and novel technique to explore such data. We designed an adaptation of this technique for min-ing Rdf data and introduce the concept of "mining configurations", which allows us to mine RDF data sets in various ways. Different configurations enable us to identify schema and value dependencies that in combination result in interesting use cases. To this end, we present rule-based approaches for auto-completion, data enrichment, ontology improvement, and query relaxation. Auto-completion remedies the problem of inconsistent ontology usage, providing an editing user with a sorted list of commonly used predicates. A combination of different configurations step extends this approach to create completely new facts for a knowledge base. We present two approaches for fact generation, a user-based approach where a user selects the entity to be amended with new facts and a data-driven approach where an algorithm discovers entities that have to be amended with missing facts. As knowledge bases constantly grow and evolve, another approach to improve the usage of RDF data is to improve existing ontologies. Here, we present an association rule based approach to reconcile ontology and data. Interlacing different mining configurations, we infer an algorithm to discover synonymously used predicates. Those predicates can be used to expand query results and to support users during query formulation. We provide a wide range of experiments on real world datasets for each use case. The experiments and evaluations show the added value of association rule mining for the integration and usability of RDF data and confirm the appropriateness of our mining configuration methodology.},
  language  = {en}
}
@book{MeyerWeske2014,
  author    = {Meyer, Andreas and Weske, Mathias},
  title     = {Weak conformance between process models and synchronized object life cycles},
  number    = {91},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  isbn      = {978-3-86956-303-9},
  issn      = {1613-5652},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-71722},
  publisher      = {Universit{\"a}t Potsdam},
  pages     = {31},
  year      = {2014},
  abstract  = {Process models specify behavioral execution constraints between activities as well as between activities and data objects. A data object is characterized by its states and state transitions represented as object life cycle. For process execution, all behavioral execution constraints must be correct. Correctness can be verified via soundness checking which currently only considers control flow information. For data correctness, conformance between a process model and its object life cycles is checked. Current approaches abstract from dependencies between multiple data objects and require fully specified process models although, in real-world process repositories, often underspecified models are found. Coping with these issues, we introduce the concept of synchronized object life cycles and we define a mapping of data constraints of a process model to Petri nets extending an existing mapping. Further, we apply the notion of weak conformance to process models to tell whether each time an activity needs to access a data object in a particular state, it is guaranteed that the data object is in or can reach the expected state. Then, we introduce an algorithm for an integrated verification of control flow correctness and weak data conformance using soundness checking.},
  language  = {en}
}
@book{OPUS4-6813,
  title     = {Cloud security mechanisms},
  number    = {87},
  editor    = {Neuhaus, Christian and Polze, Andreas},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  isbn      = {978-3-86956-281-0},
  issn      = {1613-5652},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-68168},
  publisher      = {Universit{\"a}t Potsdam},
  pages     = {78},
  year      = {2014},
  abstract  = {Cloud computing has brought great benefits in cost and flexibility for provisioning services. The greatest challenge of cloud computing remains however the question of security. The current standard tools in access control mechanisms and cryptography can only partly solve the security challenges of cloud infrastructures. In the recent years of research in security and cryptography, novel mechanisms, protocols and algorithms have emerged that offer new ways to create secure services atop cloud infrastructures. This report provides introductions to a selection of security mechanisms that were part of the "Cloud Security Mechanisms" seminar in summer term 2013 at HPI.},
  language  = {en}
}