@book{OPUS4-7230,
  title     = {Proceedings of the 8th Ph.D. retreat of the HPI research school on service-oriented systems engineering},
  number    = {95},
  editor    = {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},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  isbn      = {978-3-86956-320-6},
  issn      = {1613-5652},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-72302},
  publisher      = {Universit{\"a}t Potsdam},
  pages     = {vi, 223},
  year      = {2015},
  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}
}
@book{WaetzoldtGiese2015,
  author    = {W{\"a}tzoldt, Sebastian and Giese, Holger},
  title     = {Modeling collaborations in self-adaptive systems of systems},
  number    = {96},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  isbn      = {978-3-86956-324-4},
  issn      = {1613-5652},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-73036},
  publisher      = {Universit{\"a}t Potsdam},
  pages     = {72},
  year      = {2015},
  abstract  = {An increasing demand on functionality and flexibility leads to an integration of beforehand isolated system solutions building a so-called System of Systems (SoS). Furthermore, the overall SoS should be adaptive to react on changing requirements and environmental conditions. Due SoS are composed of different independent systems that may join or leave the overall SoS at arbitrary point in times, the SoS structure varies during the systems lifetime and the overall SoS behavior emerges from the capabilities of the contained subsystems. In such complex system ensembles new demands of understanding the interaction among subsystems, the coupling of shared system knowledge and the influence of local adaptation strategies to the overall resulting system behavior arise. In this report, we formulate research questions with the focus of modeling interactions between system parts inside a SoS. Furthermore, we define our notion of important system types and terms by retrieving the current state of the art from literature. Having a common understanding of SoS, we discuss a set of typical SoS characteristics and derive general requirements for a collaboration modeling language. Additionally, we retrieve a broad spectrum of real scenarios and frameworks from literature and discuss how these scenarios cope with different characteristics of SoS. Finally, we discuss the state of the art for existing modeling languages that cope with collaborations for different system types such as SoS.},
  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{HerbstMaschlerNiephausetal.2015,
  author    = {Herbst, Eva-Maria and Maschler, Fabian and Niephaus, Fabio and Reimann, Max and Steier, Julia and Felgentreff, Tim and Lincke, Jens and Taeumel, Marcel and Hirschfeld, Robert and Witt, Carsten},
  title     = {ecoControl},
  number    = {93},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  isbn      = {978-3-86956-318-3},
  issn      = {1613-5652},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-72147},
  publisher      = {Universit{\"a}t Potsdam},
  pages     = {viii, 142},
  year      = {2015},
  abstract  = {Eine dezentrale Energieversorgung ist ein erster Schritt in Richtung Energiewende. Dabei werden auch in Mehrfamilienh{\"a}usern vermehrt verschiedene Strom- und W{\"a}rmeerzeuger eingesetzt. Besonders in Deutschland kommen in diesem Zusammenhang Blockheizkraftwerke immer h{\"a}ufiger zum Einsatz, weil sie Gas sehr effizient in Strom und W{\"a}rme umwandeln k{\"o}nnen. Außerdem erm{\"o}glichen sie, im Zusammenspiel mit anderen Energiesystemen wie beispielsweise Photovoltaik-Anlagen, eine kontinuierliche und dezentrale Energieversorgung. Bei dem Betrieb von unterschiedlichen Energiesystemen ist es w{\"u}nschenswert, dass die Systeme aufeinander abgestimmt arbeiten. Allerdings ist es bisher schwierig, heterogene Energiesysteme effizient miteinander zu betreiben. Dadurch bleiben Einsparungspotentiale ungenutzt. Eine zentrale Steuerung kann deshalb die Effizienz des Gesamtsystems verbessern. Mit ecoControl stellen wir einen erweiterbaren Prototypen vor, der die Kooperation von Energiesystemen optimiert und Umweltfaktoren miteinbezieht. Dazu stellt die Software eine einheitliche Bedienungsoberfl{\"a}che zur Konfiguration aller Systeme zur Verf{\"u}gung. Außerdem bietet sie die M{\"o}glichkeit, Optimierungsalgorithmen mit Hilfe einer Programmierschnittstelle zu entwickeln, zu testen und auszuf{\"u}hren. Innerhalb solcher Algorithmen k{\"o}nnen von ecoControl bereitgestellte Vorhersagen genutzt werden. Diese Vorhersagen basieren auf dem individuellen Verhalten von jedem Energiesystem, Wettervorhersagen und auf Prognosen des Energieverbrauchs. Mithilfe einer Simulation k{\"o}nnen Techniker unterschiedliche Konfigurationen und Optimierungen sofort ausprobieren, ohne diese {\"u}ber einen langen Zeitraum an realen Ger{\"a}ten testen zu m{\"u}ssen. ecoControl hilft dar{\"u}ber hinaus auch Hausverwaltungen und Vermietern bei der Verwaltung und Analyse der Energiekosten. Wir haben anhand von Fallbeispielen gezeigt, dass Optimierungsalgorithmen, welche die Nutzung von W{\"a}rmespeichern verbessern, die Effizienz des Gesamtsystems erheblich verbessern k{\"o}nnen. Schließlich kommen wir zu dem Schluss, dass ecoControl in einem n{\"a}chsten Schritt unter echten Bedingungen getestet werden muss, sobald eine geeignete Hardwarekomponente verf{\"u}gbar ist. {\"U}ber diese Schnittstelle werden die Messwerte an ecoControl gesendet und Steuersignale an die Ger{\"a}te weitergeleitet.},
  language  = {de}
}
@book{OPUS4-6986,
  title     = {HPI Future SOC Lab},
  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      = {978-3-86956-276-6},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-68991},
  publisher      = {Universit{\"a}t Potsdam},
  pages     = {ii, 118},
  year      = {2013},
  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 2012. Selected projects have presented their results on June 18th and November 26th 2012 at the Future SOC Lab Day events.},
  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{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}
}
@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{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}
}
@book{FelgentreffBorningHirschfeld2013,
  author    = {Felgentreff, Tim and Borning, Alan and Hirschfeld, Robert},
  title     = {Babelsberg : specifying and solving constraints on object behavior},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  isbn      = {978-3-86956-265-0},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-67296},
  publisher      = {Universit{\"a}t Potsdam},
  pages     = {53},
  year      = {2013},
  abstract  = {Constraints allow developers to specify desired properties of systems in a number of domains, and have those properties be maintained automatically. This results in compact, declarative code, avoiding scattered code to check and imperatively re-satisfy invariants. Despite these advantages, constraint programming is not yet widespread, with standard imperative programming still the norm. There is a long history of research on integrating constraint programming with the imperative paradigm. However, this integration typically does not unify the constructs for encapsulation and abstraction from both paradigms. This impedes re-use of modules, as client code written in one paradigm can only use modules written to support that paradigm. Modules require redundant definitions if they are to be used in both paradigms. We present a language - Babelsberg - that unifies the constructs for en- capsulation and abstraction by using only object-oriented method definitions for both declarative and imperative code. Our prototype - Babelsberg/R - is an extension to Ruby, and continues to support Ruby's object-oriented se- mantics. It allows programmers to add constraints to existing Ruby programs in incremental steps by placing them on the results of normal object-oriented message sends. It is implemented by modifying a state-of-the-art Ruby virtual machine. The performance of standard object-oriented code without con- straints is only modestly impacted, with typically less than 10\% overhead compared with the unmodified virtual machine. Furthermore, our architec- ture for adding multiple constraint solvers allows Babelsberg to deal with constraints in a variety of domains. We argue that our approach provides a useful step toward making con- straint solving a generic tool for object-oriented programmers. We also provide example applications, written in our Ruby-based implementation, which use constraints in a variety of application domains, including interactive graphics, circuit simulations, data streaming with both hard and soft constraints on performance, and configuration file Management.},
  language  = {en}
}
@book{PufahlMeyerWeske2013,
  author    = {Pufahl, Luise and Meyer, Andreas and Weske, Mathias},
  title     = {Batch regions : process instance synchronization based on data},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  isbn      = {978-3-86956-280-3},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-69081},
  publisher      = {Universit{\"a}t Potsdam},
  pages     = {18},
  year      = {2013},
  abstract  = {Business process automation improves organizations' efficiency to perform work. In existing business process management systems, process instances run independently from each other. However, synchronizing instances carrying similar characteristics, i.e., sharing the same data, can reduce process execution costs. For example, if an online retailer receives two orders from one customer, there is a chance that they can be packed and shipped together to save shipment costs. In this paper, we use concepts from the database domain and introduce data views to business processes to identify instances which can be synchronized. Based on data views, we introduce the concept of batch regions for a context-aware instance synchronization over a set of connected activities. We also evaluate the concepts introduced in this paper with a case study comparing costs for normal and batch processing.},
  language  = {de}
}
@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{PapeTrefferHirschfeldetal.2013,
  author    = {Pape, Tobias and Treffer, Arian and Hirschfeld, Robert and Haupt, Michael},
  title     = {Extending a Java Virtual Machine to Dynamic Object-oriented Languages},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  isbn      = {978-3-86956-266-7},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-67438},
  publisher      = {Universit{\"a}t Potsdam},
  pages     = {163},
  year      = {2013},
  abstract  = {There are two common approaches to implement a virtual machine (VM) for a dynamic object-oriented language. On the one hand, it can be implemented in a C-like language for best performance and maximum control over the resulting executable. On the other hand, it can be implemented in a language such as Java that allows for higher-level abstractions. These abstractions, such as proper object-oriented modularization, automatic memory management, or interfaces, are missing in C-like languages but they can simplify the implementation of prevalent but complex concepts in VMs, such as garbage collectors (GCs) or just-in-time compilers (JITs). Yet, the implementation of a dynamic object-oriented language in Java eventually results in two VMs on top of each other (double stack), which impedes performance. For statically typed languages, the Maxine VM solves this problem; it is written in Java but can be executed without a Java virtual machine (JVM). However, it is currently not possible to execute dynamic object-oriented languages in Maxine. This work presents an approach to bringing object models and execution models of dynamic object-oriented languages to the Maxine VM and the application of this approach to Squeak/Smalltalk. The representation of objects in and the execution of dynamic object-oriented languages pose certain challenges to the Maxine VM that lacks certain variation points necessary to enable an effortless and straightforward implementation of dynamic object-oriented languages' execution models. The implementation of Squeak/Smalltalk in Maxine as a feasibility study is to unveil such missing variation points.},
  language  = {en}
}
@book{MeinelWillems2013,
  author    = {Meinel, Christoph and Willems, Christian},
  title     = {openHPI : the MOOC offer at Hasso Plattner Institute},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  isbn      = {978-3-86956-264-3},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-67176},
  publisher      = {Universit{\"a}t Potsdam},
  pages     = {21},
  year      = {2013},
  abstract  = {The new interactive online educational platform openHPI, (https://openHPI.de) from Hasso Plattner Institute (HPI), offers freely accessible courses at no charge for all who are interested in subjects in the field of information technology and computer science. Since 2011, "Massive Open Online Courses," called MOOCs for short, have been offered, first at Stanford University and then later at other U.S. elite universities. Following suit, openHPI provides instructional videos on the Internet and further reading material, combined with learning-supportive self-tests, homework and a social discussion forum. Education is further stimulated by the support of a virtual learning community. In contrast to "traditional" lecture platforms, such as the tele-TASK portal (http://www.tele-task.de) where multimedia recorded lectures are available on demand, openHPI offers didactic online courses. The courses have a fixed start date and offer a balanced schedule of six consecutive weeks presented in multimedia and, whenever possible, interactive learning material. Each week, one chapter of the course subject is treated. In addition, a series of learning videos, texts, self-tests and homework exercises are provided to course participants at the beginning of the week. The course offering is combined with a social discussion platform where participants have the opportunity to enter into an exchange with course instructors and fellow participants. Here, for example, they can get answers to questions and discuss the topics in depth. The participants naturally decide themselves about the type and range of their learning activities. They can make personal contributions to the course, for example, in blog posts or tweets, which they can refer to in the forum. In turn, other participants have the chance to comment on, discuss or expand on what has been said. In this way, the learners become the teachers and the subject matter offered to a virtual community is linked to a social learning network.},
  language  = {en}
}
@book{BerovHenningMattisetal.2013,
  author    = {Berov, Leonid and Henning, Johannes and Mattis, Toni and Rein, Patrick and Schreiber, Robin and Seckler, Eric and Steinert, Bastian and Hirschfeld, Robert},
  title     = {Vereinfachung der Entwicklung von Gesch{\"a}ftsanwendungen durch Konsolidierung von Programmierkonzepten und -technologien},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  isbn      = {978-3-86956-231-5},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-64045},
  publisher      = {Universit{\"a}t Potsdam},
  pages     = {186},
  year      = {2013},
  abstract  = {Die Komplexit{\"a}t heutiger Gesch{\"a}ftsabl{\"a}ufe und die Menge der zu verwaltenden Daten stellen hohe Anforderungen an die Entwicklung und Wartung von Gesch{\"a}ftsanwendungen. Ihr Umfang entsteht unter anderem aus der Vielzahl von Modellentit{\"a}ten und zugeh{\"o}rigen Nutzeroberfl{\"a}chen zur Bearbeitung und Analyse der Daten. Dieser Bericht pr{\"a}sentiert neuartige Konzepte und deren Umsetzung zur Vereinfachung der Entwicklung solcher umfangreichen Gesch{\"a}ftsanwendungen. Erstens: Wir schlagen vor, die Datenbank und die Laufzeitumgebung einer dynamischen objektorientierten Programmiersprache zu vereinen. Hierzu organisieren wir die Speicherstruktur von Objekten auf die Weise einer spaltenorientierten Hauptspeicherdatenbank und integrieren darauf aufbauend Transaktionen sowie eine deklarative Anfragesprache nahtlos in dieselbe Laufzeitumgebung. Somit k{\"o}nnen transaktionale und analytische Anfragen in derselben objektorientierten Hochsprache implementiert werden, und dennoch nah an den Daten ausgef{\"u}hrt werden. Zweitens: Wir beschreiben Programmiersprachkonstrukte, welche es erlauben, Nutzeroberfl{\"a}chen sowie Nutzerinteraktionen generisch und unabh{\"a}ngig von konkreten Modellentit{\"a}ten zu beschreiben. Um diese abstrakte Beschreibung nutzen zu k{\"o}nnen, reichert man die Dom{\"a}nenmodelle um vormals implizite Informationen an. Neue Modelle m{\"u}ssen nur um einige Informationen erweitert werden um bereits vorhandene Nutzeroberfl{\"a}chen und -interaktionen auch f{\"u}r sie verwenden zu k{\"o}nnen. Anpassungen, die nur f{\"u}r ein Modell gelten sollen, k{\"o}nnen unabh{\"a}ngig vom Standardverhalten, inkrementell, definiert werden. Drittens: Wir erm{\"o}glichen mit einem weiteren Programmiersprachkonstrukt die zusammenh{\"a}ngende Beschreibung von Abl{\"a}ufen der Anwendung, wie z.B. Bestellprozesse. Unser Programmierkonzept kapselt Nutzerinteraktionen in synchrone Funktionsaufrufe und macht somit Prozesse als zusammenh{\"a}ngende Folge von Berechnungen und Interaktionen darstellbar. Viertens: Wir demonstrieren ein Konzept, wie Endnutzer komplexe analytische Anfragen intuitiver formulieren k{\"o}nnen. Es basiert auf der Idee, dass Endnutzer Anfragen als Konfiguration eines Diagramms sehen. Entsprechend beschreibt ein Nutzer eine Anfrage, indem er beschreibt, was sein Diagramm darstellen soll. Nach diesem Konzept beschriebene Diagramme enthalten ausreichend Informationen, um daraus eine Anfrage generieren zu k{\"o}nnen. Hinsichtlich der Ausf{\"u}hrungsdauer sind die generierten Anfragen {\"a}quivalent zu Anfragen, die mit konventionellen Anfragesprachen formuliert sind. Das Anfragemodell setzen wir in einem Prototypen um, der auf den zuvor eingef{\"u}hrten Konzepten aufsetzt.},
  language  = {de}
}
@book{OPUS4-6472,
  title     = {Proceedings of the 6th Ph.D. Retreat of the HPI Research School on Service-oriented Systems Engineering},
  editor    = {Meinel, Christoph and Plattner, Hasso and D{\"o}llner, J{\"u}rgen Roland Friedrich and Naumann, Felix and Giese, Holger and Hirschfeld, Robert and Weske, Mathias and Polze, Andreas and Baudisch, Patrick},
  isbn      = {978-3-86956-256-8},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-66777},
  publisher      = {Universit{\"a}t Potsdam},
  year      = {2013},
  language  = {mul}
}
@book{RoggeSoltiMansvanderAalstetal.2013,
  author    = {Rogge-Solti, Andreas and Mans, Ronny S. and van der Aalst, Wil M. P. and Weske, Mathias},
  title     = {Repairing event logs using stochastic process models},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  isbn      = {978-3-86956-258-2},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-66797},
  publisher      = {Universit{\"a}t Potsdam},
  pages     = {19},
  year      = {2013},
  abstract  = {Companies strive to improve their business processes in order to remain competitive. Process mining aims to infer meaningful insights from process-related data and attracted the attention of practitioners, tool-vendors, and researchers in recent years. Traditionally, event logs are assumed to describe the as-is situation. But this is not necessarily the case in environments where logging may be compromised due to manual logging. For example, hospital staff may need to manually enter information regarding the patient's treatment. As a result, events or timestamps may be missing or incorrect. In this paper, we make use of process knowledge captured in process models, and provide a method to repair missing events in the logs. This way, we facilitate analysis of incomplete logs. We realize the repair by combining stochastic Petri nets, alignments, and Bayesian networks. We evaluate the results using both synthetic data and real event data from a Dutch hospital.},
  language  = {en}
}
@book{EidSabbaghHeweltWeske2013,
  author    = {Eid-Sabbagh, Rami-Habib and Hewelt, Marcin and Weske, Mathias},
  title     = {Business process architectures with multiplicities : transformation and correctness},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  isbn      = {978-3-86956-257-5},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-66780},
  publisher      = {Universit{\"a}t Potsdam},
  pages     = {18},
  year      = {2013},
  abstract  = {Business processes are instrumental to manage work in organisations. To study the interdependencies between business processes, Business Process Architectures have been introduced. These express trigger and message ow relations between business processes. When we investigate real world Business Process Architectures, we find complex interdependencies, involving multiple process instances. These aspects have not been studied in detail so far, especially concerning correctness properties. In this paper, we propose a modular transformation of BPAs to open nets for the analysis of behavior involving multiple business processes with multiplicities. For this purpose we introduce intermediary nets to portray semantics of multiplicity specifications. We evaluate our approach on a use case from the public sector.},
  language  = {en}
}
@book{MeyerPufahlFahlandetal.2013,
  author    = {Meyer, Andreas and Pufahl, Luise and Fahland, Dirk and Weske, Mathias},
  title     = {Modeling and enacting complex data dependencies in business processes},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  isbn      = {978-3-86956-245-2},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-65103},
  publisher      = {Universit{\"a}t Potsdam},
  pages     = {40},
  year      = {2013},
  abstract  = {Enacting business processes in process engines requires the coverage of control flow, resource assignments, and process data. While the first two aspects are well supported in current process engines, data dependencies need to be added and maintained manually by a process engineer. Thus, this task is error-prone and time-consuming. In this report, we address the problem of modeling processes with complex data dependencies, e.g., m:n relationships, and their automatic enactment from process models. First, we extend BPMN data objects with few annotations to allow data dependency handling as well as data instance differentiation. Second, we introduce a pattern-based approach to derive SQL queries from process models utilizing the above mentioned extensions. Therewith, we allow automatic enactment of data-aware BPMN process models. We implemented our approach for the Activiti process engine to show applicability.},
  language  = {en}
}
@book{MeinelWillems2013,
  author    = {Meinel, Christoph and Willems, Christian},
  title     = {openHPI : das MOOC-Angebot des Hasso-Plattner-Instituts},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  isbn      = {978-3-86956-259-9},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-66802},
  publisher      = {Universit{\"a}t Potsdam},
  pages     = {22},
  year      = {2013},
  abstract  = {Die neue interaktive Online-Bildungsplattform openHPI (https://openHPI.de) des Hasso-Plattner-Instituts (HPI) bietet frei zug{\"a}ngliche und kostenlose Onlinekurse f{\"u}r interessierte Teilnehmer an, die sich mit Inhalten aus dem Bereich der Informationstechnologien und Informatik besch{\"a}ftige¬n. Wie die seit 2011 zun{\"a}chst von der Stanford University, sp{\"a}ter aber auch von anderen Elite-Universit{\"a}ten der USA angeboten „Massive Open Online Courses", kurz MOOCs genannt, bietet openHPI im Internet Lernvideos und weiterf{\"u}hrenden Lesestoff in einer Kombination mit lernunterst{\"u}tzenden Selbsttests, Hausaufgaben und einem sozialen Diskussionsforum an und stimuliert die Ausbildung einer das Lernen f{\"o}rdernden virtuellen Lerngemeinschaft. Im Unterschied zu „traditionellen" Vorlesungsportalen, wie z.B. dem tele-TASK Portal (http://www.tele-task.de), bei dem multimedial aufgezeichnete Vorlesungen zum Abruf bereit gestellt werden, bietet openHPI didaktisch aufbereitete Onlinekurse an. Diese haben einen festen Starttermin und bieten dann in einem austarierten Zeitplan von sechs aufeinanderfolgenden Kurswochen multimedial aufbereitete und wann immer m{\"o}glich interaktive Lehrmaterialien. In jeder Woche wird ein Kapitel des Kursthemas behandelt. Dazu werden zu Wochenbeginn eine Reihe von Lehrvideos, Texten, Selbsttests und ein Hausaufgabenblatt bereitgestellt, mit denen sich die Kursteilnehmer in dieser Woche besch{\"a}ftigen. Kombiniert sind die Angebote mit einer sozialen Diskussionsplattform, auf der sich die Teilnehmer mit den Kursbetreuern und anderen Teilnehmern austauschen, Fragen kl{\"a}ren und weiterf{\"u}hrende Themen diskutieren k{\"o}nnen. Nat{\"u}rlich entscheiden die Teilnehmer selbst {\"u}ber Art und Umfang ihrer Lernaktivit{\"a}ten. Sie k{\"o}nnen in den Kurs eigene Beitr{\"a}ge einbringen, zum Beispiel durch Blogposts oder Tweets, auf die sie im Forum verweisen. Andere Lernende k{\"o}nnen diese dann kommentieren, diskutieren oder ihrerseits erweitern. Auf diese Weise werden die Lernenden, die Lehrenden und die angebotenen Lerninhalte in einer virtuellen Gemeinschaft, einem sozialen Lernnetzwerk miteinander verkn{\"u}pft.},
  language  = {de}
}