@phdthesis{Wang2011, author = {Wang, Long}, title = {X-tracking the usage interest on web sites}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-51077}, school = {Universit{\"a}t Potsdam}, year = {2011}, abstract = {The exponential expanding of the numbers of web sites and Internet users makes WWW the most important global information resource. From information publishing and electronic commerce to entertainment and social networking, the Web allows an inexpensive and efficient access to the services provided by individuals and institutions. The basic units for distributing these services are the web sites scattered throughout the world. However, the extreme fragility of web services and content, the high competence between similar services supplied by different sites, and the wide geographic distributions of the web users drive the urgent requirement from the web managers to track and understand the usage interest of their web customers. This thesis, "X-tracking the Usage Interest on Web Sites", aims to fulfill this requirement. "X" stands two meanings: one is that the usage interest differs from various web sites, and the other is that usage interest is depicted from multi aspects: internal and external, structural and conceptual, objective and subjective. "Tracking" shows that our concentration is on locating and measuring the differences and changes among usage patterns. This thesis presents the methodologies on discovering usage interest on three kinds of web sites: the public information portal site, e-learning site that provides kinds of streaming lectures and social site that supplies the public discussions on IT issues. On different sites, we concentrate on different issues related with mining usage interest. The educational information portal sites were the first implementation scenarios on discovering usage patterns and optimizing the organization of web services. In such cases, the usage patterns are modeled as frequent page sets, navigation paths, navigation structures or graphs. However, a necessary requirement is to rebuild the individual behaviors from usage history. We give a systematic study on how to rebuild individual behaviors. Besides, this thesis shows a new strategy on building content clusters based on pair browsing retrieved from usage logs. The difference between such clusters and the original web structure displays the distance between the destinations from usage side and the expectations from design side. Moreover, we study the problem on tracking the changes of usage patterns in their life cycles. The changes are described from internal side integrating conceptual and structure features, and from external side for the physical features; and described from local side measuring the difference between two time spans, and global side showing the change tendency along the life cycle. A platform, Web-Cares, is developed to discover the usage interest, to measure the difference between usage interest and site expectation and to track the changes of usage patterns. E-learning site provides the teaching materials such as slides, recorded lecture videos and exercise sheets. We focus on discovering the learning interest on streaming lectures, such as real medias, mp4 and flash clips. Compared to the information portal site, the usage on streaming lectures encapsulates the variables such as viewing time and actions during learning processes. The learning interest is discovered in the form of answering 6 questions, which covers finding the relations between pieces of lectures and the preference among different forms of lectures. We prefer on detecting the changes of learning interest on the same course from different semesters. The differences on the content and structure between two courses leverage the changes on the learning interest. We give an algorithm on measuring the difference on learning interest integrated with similarity comparison between courses. A search engine, TASK-Moniminer, is created to help the teacher query the learning interest on their streaming lectures on tele-TASK site. Social site acts as an online community attracting web users to discuss the common topics and share their interesting information. Compared to the public information portal site and e-learning web site, the rich interactions among users and web content bring the wider range of content quality, on the other hand, provide more possibilities to express and model usage interest. We propose a framework on finding and recommending high reputation articles in a social site. We observed that the reputation is classified into global and local categories; the quality of the articles having high reputation is related with the content features. Based on these observations, our framework is implemented firstly by finding the articles having global or local reputation, and secondly clustering articles based on their content relations, and then the articles are selected and recommended from each cluster based on their reputation ranks.}, language = {en} } @book{OPUS4-5707, title = {Web-based development in the lively kernel}, editor = {Lincke, Jens and Hirschfeld, Robert}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-160-8}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-55605}, publisher = {Universit{\"a}t Potsdam}, pages = {I, 55}, year = {2011}, abstract = {The World Wide Web as an application platform becomes increasingly important. However, the development of Web applications is often more complex than for the desktop. Web-based development environments like Lively Webwerkstatt can mitigate this problem by making the development process more interactive and direct. By moving the development environment into the Web, applications can be developed collaboratively in a Wiki-like manner. This report documents the results of the project seminar on Web-based Development Environments 2010. In this seminar, participants extended the Web-based development environment Lively Webwerkstatt. They worked in small teams on current research topics from the field of Web-development and tool support for programmers and implemented their results in the Webwerkstatt environment.}, language = {en} } @article{AwadWeidlichWeske2011, author = {Awad, Ahmed Mahmoud Hany Aly and Weidlich, Matthias and Weske, Mathias}, title = {Visually specifying compliance rules and explaining their violations for business processes}, series = {Journal of visual languages and computing}, volume = {22}, journal = {Journal of visual languages and computing}, number = {1}, publisher = {Elsevier}, address = {London}, issn = {1045-926X}, doi = {10.1016/j.jvlc.2010.11.002}, pages = {30 -- 55}, year = {2011}, abstract = {A business process is a set of steps designed to be executed in a certain order to achieve a business value. Such processes are often driven by and documented using process models. Nowadays, process models are also applied to drive process execution. Thus, correctness of business process models is a must. Much of the work has been devoted to check general, domain-independent correctness criteria, such as soundness. However, business processes must also adhere to and show compliance with various regulations and constraints, the so-called compliance requirements. These are domain-dependent requirements. In many situations, verifying compliance on a model level is of great value, since violations can be resolved in an early stage prior to execution. However, this calls for using formal verification techniques, e.g., model checking, that are too complex for business experts to apply. In this paper, we utilize a visual language. BPMN-Q to express compliance requirements visually in a way similar to that used by business experts to build process models. Still, using a pattern based approach, each BPMN-Qgraph has a formal temporal logic expression in computational tree logic (CTL). Moreover, the user is able to express constraints, i.e., compliance rules, regarding control flow and data flow aspects. In order to provide valuable feedback to a user in case of violations, we depend on temporal logic querying approaches as well as BPMN-Q to visually highlight paths in a process model whose execution causes violations.}, language = {en} } @article{LaueAwad2011, author = {Laue, Ralf and Awad, Ahmed Mahmoud Hany Aly}, title = {Visual suggestions for improvements in business process diagrams}, series = {Journal of visual languages and computing}, volume = {22}, journal = {Journal of visual languages and computing}, number = {5}, publisher = {Elsevier}, address = {London}, issn = {1045-926X}, doi = {10.1016/j.jvlc.2011.04.003}, pages = {385 -- 399}, year = {2011}, abstract = {Business processes are commonly modeled using a graphical modeling language. The most widespread notation for this purpose is business process diagrams in the Business Process Modeling Notation (BPMN). In this article, we use the visual query language BPMN-Q for expressing patterns that are related to possible problems in such business process diagrams. We discuss two classes of problems that can be found frequently in real-world models: sequence flow errors and model fragments that can make the model difficult to understand. By using a query processor, a business process modeler is able to identify possible errors in business process diagrams. Moreover, the erroneous parts of the business process diagram can be highlighted when an instance of an error pattern is found. This way, the modeler gets an easy-to-understand feedback in the visual modeling language he or she is familiar with. This is an advantage over current validation methods, which usually lack this kind of intuitive feedback.}, language = {en} } @article{ProtzmannSchuenemannRadusch2011, author = {Protzmann, Robert and Sch{\"u}nemann, Bjoern and Radusch, Ilja}, title = {The Influences of communication models on the simulated effectiveness of V2X Applications}, series = {IEEE communications magazine}, volume = {49}, journal = {IEEE communications magazine}, number = {11}, publisher = {Inst. of Electr. and Electronics Engineers}, address = {Piscataway}, issn = {0163-6804}, pages = {149 -- 155}, year = {2011}, abstract = {In this article, we aim to evaluate the influences of different propagation models on the results of V2X simulations. First, we analyze how the models free space propagation, Rayleigh fading, and Ricean fading in synthetic scenarios with and without background communication influence the simulation of communication in general. After that, we investigate the impact of the models on the simulated behavior of a V2X traffic efficiency application in a real inner city scenario. Our results show that the selection of the propagation model affects the number of delivered messages, but exerts no significant influence on the simulated effectiveness of a V2X traffic efficiency application in urban areas. Under those circumstances, a simplified propagation model is sufficient.}, language = {en} } @book{Luebbe2011, author = {L{\"u}bbe, Alexander}, title = {The effect of tangible media on individuals in business process modeling : a controlled experiment = Der Einfluss greifbarer Medien auf einzelne Personen bei der Gesch{\"a}ftsprozessmodellierung : ein kontrolliertes Experiment}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-108-0}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-49001}, publisher = {Universit{\"a}t Potsdam}, pages = {42}, year = {2011}, abstract = {In current practice, business processes modeling is done by trained method experts. Domain experts are interviewed to elicit their process information but not involved in modeling. We created a haptic toolkit for process modeling that can be used in process elicitation sessions with domain experts. We hypothesize that this leads to more effective process elicitation. This paper brakes down "effective elicitation" to 14 operationalized hypotheses. They are assessed in a controlled experiment using questionnaires, process model feedback tests and video analysis. The experiment compares our approach to structured interviews in a repeated measurement design. We executed the experiment with 17 student clerks from a trade school. They represent potential users of the tool. Six out of fourteen hypotheses showed significant difference due to the method applied. Subjects reported more fun and more insights into process modeling with tangible media. Video analysis showed significantly more reviews and corrections applied during process elicitation. Moreover, people take more time to talk and think about their processes. We conclude that tangible media creates a different working mode for people in process elicitation with fun, new insights and instant feedback on preliminary results.}, language = {en} } @book{NeuhausPolzeChowdhuryy2011, author = {Neuhaus, Christian and Polze, Andreas and Chowdhuryy, Mohammad M. R.}, title = {Survey on healthcare IT systems : standards, regulations and security}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-128-8}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-51463}, publisher = {Universit{\"a}t Potsdam}, pages = {53}, year = {2011}, abstract = {IT systems for healthcare are a complex and exciting field. One the one hand, there is a vast number of improvements and work alleviations that computers can bring to everyday healthcare. Some ways of treatment, diagnoses and organisational tasks were even made possible by computer usage in the first place. On the other hand, there are many factors that encumber computer usage and make development of IT systems for healthcare a challenging, sometimes even frustrating task. These factors are not solely technology-related, but just as well social or economical conditions. This report describes some of the idiosyncrasies of IT systems in the healthcare domain, with a special focus on legal regulations, standards and security.}, language = {en} } @book{SmirnovZamaniFarahaniWeske2011, author = {Smirnov, Sergey and Zamani Farahani, Armin and Weske, Mathias}, title = {State propagation in abstracted business processes}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-130-1}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-51480}, publisher = {Universit{\"a}t Potsdam}, pages = {16}, year = {2011}, abstract = {Business process models are abstractions of concrete operational procedures that occur in the daily business of organizations. To cope with the complexity of these models, business process model abstraction has been introduced recently. Its goal is to derive from a detailed process model several abstract models that provide a high-level understanding of the process. While techniques for constructing abstract models are reported in the literature, little is known about the relationships between process instances and abstract models. In this paper we show how the state of an abstract activity can be calculated from the states of related, detailed process activities as they happen. The approach uses activity state propagation. With state uniqueness and state transition correctness we introduce formal properties that improve the understanding of state propagation. Algorithms to check these properties are devised. Finally, we use behavioral profiles to identify and classify behavioral inconsistencies in abstract process models that might occur, once activity state propagation is used.}, language = {en} } @article{YeungNollGibbinsetal.2011, author = {Yeung, Ching-man Au and Noll, Michael G. and Gibbins, Nicholas and Meinel, Christoph and Shadbolt, Nigel}, title = {Spear spamming-resistant expertise analysis and ranking incollaborative tagging systems}, series = {Computational intelligence}, volume = {27}, journal = {Computational intelligence}, number = {3}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0824-7935}, doi = {10.1111/j.1467-8640.2011.00384.x}, pages = {458 -- 488}, year = {2011}, abstract = {In this article, we discuss the notions of experts and expertise in resource discovery in the context of collaborative tagging systems. We propose that the level of expertise of a user with respect to a particular topic is mainly determined by two factors. First, an expert should possess a high-quality collection of resources, while the quality of a Web resource in turn depends on the expertise of the users who have assigned tags to it, forming a mutual reinforcement relationship. Second, an expert should be one who tends to identify interesting or useful resources before other users discover them, thus bringing these resources to the attention of the community of users. We propose a graph-based algorithm, SPEAR (spamming-resistant expertise analysis and ranking), which implements the above ideas for ranking users in a folksonomy. Our experiments show that our assumptions on expertise in resource discovery, and SPEAR as an implementation of these ideas, allow us to promote experts and demote spammers at the same time, with performance significantly better than the original hypertext-induced topic search algorithm and simple statistical measures currently used in most collaborative tagging systems.}, language = {en} } @article{WistSchaeferVogleretal.2011, author = {Wist, Dominic and Schaefer, Mark and Vogler, Walter and Wollowski, Ralf}, title = {Signal transition graph decomposition internal communication for speed independent circuit implementation}, series = {IET Computers and digital techniques}, volume = {5}, journal = {IET Computers and digital techniques}, number = {6}, publisher = {Institution of Engineering and Technology}, address = {Hertford}, issn = {1751-8601}, doi = {10.1049/iet-cdt.2010.0162}, pages = {440 -- 451}, year = {2011}, abstract = {Logic synthesis of speed independent circuits based on signal transition graph (STG) decomposition is a promising approach to tackle complexity problems like state-space explosion. Unfortunately, decomposition can result in components that in isolation have irreducible complete state coding conflicts. In earlier work, the authors showed how to resolve such conflicts by introducing internal communication between components, but only for very restricted specification structures. Here, they improve their former work by presenting algorithms for identifying delay transitions and inserting gyroscopes for specifications having a much more general structure. Thus, the authors are now able to synthesise controllers from real-life specifications. For all algorithms, they present correctness proofs and show their successful application to benchmarks, including very complex STGs arising in the context of control resynthesis.}, language = {en} } @phdthesis{Kluth2011, author = {Kluth, Stephan}, title = {Quantitative modeling and analysis with FMC-QE}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-52987}, school = {Universit{\"a}t Potsdam}, year = {2011}, abstract = {The modeling and evaluation calculus FMC-QE, the Fundamental Modeling Concepts for Quanti-tative Evaluation [1], extends the Fundamental Modeling Concepts (FMC) for performance modeling and prediction. In this new methodology, the hierarchical service requests are in the main focus, because they are the origin of every service provisioning process. Similar to physics, these service requests are a tuple of value and unit, which enables hierarchical service request transformations at the hierarchical borders and therefore the hierarchical modeling. Through reducing the model complexity of the models by decomposing the system in different hierarchical views, the distinction between operational and control states and the calculation of the performance values on the assumption of the steady state, FMC-QE has a scalable applica-bility on complex systems. According to FMC, the system is modeled in a 3-dimensional hierarchical representation space, where system performance parameters are described in three arbitrarily fine-grained hierarchi-cal bipartite diagrams. The hierarchical service request structures are modeled in Entity Relationship Diagrams. The static server structures, divided into logical and real servers, are de-scribed as Block Diagrams. The dynamic behavior and the control structures are specified as Petri Nets, more precisely Colored Time Augmented Petri Nets. From the structures and pa-rameters of the performance model, a hierarchical set of equations is derived. The calculation of the performance values is done on the assumption of stationary processes and is based on fundamental laws of the performance analysis: Little's Law and the Forced Traffic Flow Law. Little's Law is used within the different hierarchical levels (horizontal) and the Forced Traffic Flow Law is the key to the dependencies among the hierarchical levels (vertical). This calculation is suitable for complex models and allows a fast (re-)calculation of different performance scenarios in order to support development and configuration decisions. Within the Research Group Zorn at the Hasso Plattner Institute, the work is embedded in a broader research in the development of FMC-QE. While this work is concentrated on the theoretical background, description and definition of the methodology as well as the extension and validation of the applicability, other topics are in the development of an FMC-QE modeling and evaluation tool and the usage of FMC-QE in the design of an adaptive transport layer in order to fulfill Quality of Service and Service Level Agreements in volatile service based environments. This thesis contains a state-of-the-art, the description of FMC-QE as well as extensions of FMC-QE in representative general models and case studies. In the state-of-the-art part of the thesis in chapter 2, an overview on existing Queueing Theory and Time Augmented Petri Net models and other quantitative modeling and evaluation languages and methodologies is given. Also other hierarchical quantitative modeling frameworks will be considered. The description of FMC-QE in chapter 3 consists of a summary of the foundations of FMC-QE, basic definitions, the graphical notations, the FMC-QE Calculus and the modeling of open queueing networks as an introductory example. The extensions of FMC-QE in chapter 4 consist of the integration of the summation method in order to support the handling of closed networks and the modeling of multiclass and semaphore scenarios. Furthermore, FMC-QE is compared to other performance modeling and evaluation approaches. In the case study part in chapter 5, proof-of-concept examples, like the modeling of a service based search portal, a service based SAP NetWeaver application and the Axis2 Web service framework will be provided. Finally, conclusions are given by a summary of contributions and an outlook on future work in chapter 6. [1] Werner Zorn. FMC-QE - A New Approach in Quantitative Modeling. In Hamid R. Arabnia, editor, Procee-dings of the International Conference on Modeling, Simulation and Visualization Methods (MSV 2007) within WorldComp '07, pages 280 - 287, Las Vegas, NV, USA, June 2007. CSREA Press. ISBN 1-60132-029-9.}, language = {en} } @article{WeidlichPolyvyanyyDesaietal.2011, author = {Weidlich, Matthias and Polyvyanyy, Artem and Desai, Nirmit and Mendling, Jan and Weske, Mathias}, title = {Process compliance analysis based on behavioural profiles}, series = {Information systems}, volume = {36}, journal = {Information systems}, number = {7}, publisher = {Elsevier}, address = {Oxford}, issn = {0306-4379}, doi = {10.1016/j.is.2011.04.002}, pages = {1009 -- 1025}, year = {2011}, abstract = {Process compliance measurement is getting increasing attention in companies due to stricter legal requirements and market pressure for operational excellence. In order to judge on compliance of the business processing, the degree of behavioural deviation of a case, i.e., an observed execution sequence, is quantified with respect to a process model (referred to as fitness, or recall). Recently, different compliance measures have been proposed. Still, nearly all of them are grounded on state-based techniques and the trace equivalence criterion, in particular. As a consequence, these approaches have to deal with the state explosion problem. In this paper, we argue that a behavioural abstraction may be leveraged to measure the compliance of a process log - a collection of cases. To this end, we utilise causal behavioural profiles that capture the behavioural characteristics of process models and cases, and can be computed efficiently. We propose different compliance measures based on these profiles, discuss the impact of noise in process logs on our measures, and show how diagnostic information on non-compliance is derived. As a validation, we report on findings of applying our approach in a case study with an international service provider.}, language = {en} } @book{OPUS4-4807, title = {Proceedings of the Fall 2010 Future SOC Lab Day}, editor = {Meinel, Christoph and Polze, Andreas and Zeier, Alexander}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-114-1}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-49761}, publisher = {Universit{\"a}t Potsdam}, pages = {ii, 75}, year = {2011}, abstract = {In Kooperation mit Partnern aus der Industrie etabliert das Hasso-Plattner-Institut (HPI) ein "HPI Future SOC Lab", das eine komplette Infrastruktur von hochkomplexen on-demand Systemen auf neuester, am Markt noch nicht verf{\"u}gbarer, massiv paralleler (multi-/many-core) Hardware mit enormen Hauptspeicherkapazit{\"a}ten und daf{\"u}r konzipierte Software bereitstellt. Das HPI Future SOC Lab verf{\"u}gt {\"u}ber prototypische 4- und 8-way Intel 64-Bit Serversysteme von Fujitsu und Hewlett-Packard mit 32- bzw. 64-Cores und 1 - 2 TB Hauptspeicher. Es kommen weiterhin hochperformante Speichersysteme von EMC² sowie Virtualisierungsl{\"o}sungen von VMware zum Einsatz. SAP stellt ihre neueste Business by Design (ByD) Software zur Verf{\"u}gung und auch komplexe reale Unternehmensdaten stehen zur Verf{\"u}gung, auf die f{\"u}r Forschungszwecke zugegriffen werden kann. Interessierte Wissenschaftler aus universit{\"a}ren und außeruniversit{\"a}ren Forschungsinstitutionen k{\"o}nnen im HPI Future SOC Lab zuk{\"u}nftige hoch-komplexe IT-Systeme untersuchen, neue Ideen / Datenstrukturen / Algorithmen entwickeln und bis hin zur praktischen Erprobung verfolgen. Dieser Technische Bericht stellt erste Ergebnisse der im Rahmen der Er{\"o}ffnung des Future SOC Labs im Juni 2010 gestarteten Forschungsprojekte vor. Ausgew{\"a}hlte Projekte stellten ihre Ergebnisse am 27. Oktober 2010 im Rahmen der Future SOC Lab Tag Veranstaltung vor.}, language = {en} } @book{OPUS4-5053, title = {Proceedings of the 5th 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 Weske, Mathias and Polze, Andreas and Hirschfeld, Robert and Naumann, Felix and Giese, Holger}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-129-5}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-51472}, publisher = {Universit{\"a}t Potsdam}, pages = {II, 228}, year = {2011}, language = {en} } @phdthesis{Menzel2011, author = {Menzel, Michael}, title = {Model-driven security in service-oriented architectures : leveraging security patterns to transform high-level security requirements to technical policies}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-59058}, school = {Universit{\"a}t Potsdam}, year = {2011}, abstract = {Service-oriented Architectures (SOA) facilitate the provision and orchestration of business services to enable a faster adoption to changing business demands. Web Services provide a technical foundation to implement this paradigm on the basis of XML-messaging. However, the enhanced flexibility of message-based systems comes along with new threats and risks. To face these issues, a variety of security mechanisms and approaches is supported by the Web Service specifications. The usage of these security mechanisms and protocols is configured by stating security requirements in security policies. However, security policy languages for SOA are complex and difficult to create due to the expressiveness of these languages. To facilitate and simplify the creation of security policies, this thesis presents a model-driven approach that enables the generation of complex security policies on the basis of simple security intentions. SOA architects can specify these intentions in system design models and are not required to deal with complex technical security concepts. The approach introduced in this thesis enables the enhancement of any system design modelling languages - for example FMC or BPMN - with security modelling elements. The syntax, semantics, and notion of these elements is defined by our security modelling language SecureSOA. The metamodel of this language provides extension points to enable the integration into system design modelling languages. In particular, this thesis demonstrates the enhancement of FMC block diagrams with SecureSOA. To enable the model-driven generation of security policies, a domain-independent policy model is introduced in this thesis. This model provides an abstraction layer for security policies. Mappings are used to perform the transformation from our model to security policy languages. However, expert knowledge is required to generate instances of this model on the basis of simple security intentions. Appropriate security mechanisms, protocols and options must be chosen and combined to fulfil these security intentions. In this thesis, a formalised system of security patterns is used to represent this knowledge and to enable an automated transformation process. Moreover, a domain-specific language is introduced to state security patterns in an accessible way. On the basis of this language, a system of security configuration patterns is provided to transform security intentions related to data protection and identity management. The formal semantics of the security pattern language enable the verification of the transformation process introduced in this thesis and prove the correctness of the pattern application. Finally, our SOA Security LAB is presented that demonstrates the application of our model-driven approach to facilitate a dynamic creation, configuration, and execution of secure Web Service-based composed applications.}, language = {en} } @article{HenklerOberthuerGieseetal.2011, author = {Henkler, Stefan and Oberthuer, Simon and Giese, Holger and Seibel, Andreas}, title = {Model-driven runtime resource predictions for advanced mechatronic systems with dynamic data structures}, series = {Computer systems science and engineering}, volume = {26}, journal = {Computer systems science and engineering}, number = {6}, publisher = {IOP Publ. Ltd.}, address = {Leicester}, issn = {0267-6192}, pages = {505 -- 518}, year = {2011}, abstract = {The next generation of advanced mechatronic systems is expected to enhance their functionality and improve their performance by context-dependent behavior. Therefore, these systems require to represent information about their complex environment and changing sets of collaboration partners internally. This requirement is in contrast to the usually assumed static structures of embedded systems. In this paper, we present a model-driven approach which overcomes this situation by supporting dynamic data structures while still guaranteeing that valid worst-case execution times can be derived. It supports a flexible resource manager which avoids to operate with the prohibitive coarse worst-case boundaries but instead supports to run applications in different profiles which guarantee different resource requirements and put unused resources in a profile at other applications' disposal. By supporting the proper estimation of worst case execution time (WCET) and worst case number of iteration (WCNI) at runtime, we can further support to create new profiles, add or remove them at runtime in order to minimize the over-approximation of the resource consumption resulting from the dynamic data structures required for the outlined class of advanced systems.}, language = {en} } @article{DeckerWeske2011, author = {Decker, Gero and Weske, Mathias}, title = {Interaction-centric modeling of process choreographies}, series = {Information systems}, volume = {36}, journal = {Information systems}, number = {2}, publisher = {Elsevier}, address = {Oxford}, issn = {0306-4379}, doi = {10.1016/j.is.2010.06.005}, pages = {292 -- 312}, year = {2011}, abstract = {With the rise of electronic integration between organizations, the need for a precise specification of interaction behavior increases. Information systems, replacing interaction previously carried out by humans via phone, faxes and emails, require a precise specification for handling all possible situations. Such interaction behavior is described in process choreographies. While many proposals for choreography languages have already been made, most of them fall into the category of interconnection models, where the observable behavior of the different partners is described and then related via message flow. As this article will show, this modeling approach fails to support fundamental design principles of choreographies and typically leads to modeling errors. This motivates an alternative modeling style, namely interaction modeling, for overcoming these limitations. While the main concepts are independent of a concrete modeling language, iBPMN is introduced as novel interaction modeling language. Formal execution semantics are provided and a comprehensive toolset implementing the approach is presented.}, language = {en} } @book{HauptMarrHirschfeld2011, author = {Haupt, Michael and Marr, Stefan and Hirschfeld, Robert}, title = {CSOM/PL : a virtual machine product line}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-134-9}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-52332}, publisher = {Universit{\"a}t Potsdam}, pages = {26}, year = {2011}, abstract = {CSOM/PL is a software product line (SPL) derived from applying multi-dimensional separation of concerns (MDSOC) techniques to the domain of high-level language virtual machine (VM) implementations. For CSOM/PL, we modularised CSOM, a Smalltalk VM implemented in C, using VMADL (virtual machine architecture description language). Several features of the original CSOM were encapsulated in VMADL modules and composed in various combinations. In an evaluation of our approach, we show that applying MDSOC and SPL principles to a domain as complex as that of VMs is not only feasible but beneficial, as it improves understandability, maintainability, and configurability of VM implementations without harming performance.}, language = {en} } @article{WeidlichPolyvyanyyMendlingetal.2011, author = {Weidlich, Matthias and Polyvyanyy, Artem and Mendling, Jan and Weske, Mathias}, title = {Causal behavioural profiles - efficient computation, applications, and evaluation}, series = {Fundamenta informaticae}, volume = {113}, journal = {Fundamenta informaticae}, number = {3-4}, publisher = {IOS Press}, address = {Amsterdam}, issn = {0169-2968}, doi = {10.3233/FI-2011-614}, pages = {399 -- 435}, year = {2011}, abstract = {Analysis of behavioural consistency is an important aspect of software engineering. In process and service management, consistency verification of behavioural models has manifold applications. For instance, a business process model used as system specification and a corresponding workflow model used as implementation have to be consistent. Another example would be the analysis to what degree a process log of executed business operations is consistent with the corresponding normative process model. Typically, existing notions of behaviour equivalence, such as bisimulation and trace equivalence, are applied as consistency notions. Still, these notions are exponential in computation and yield a Boolean result. In many cases, however, a quantification of behavioural deviation is needed along with concepts to isolate the source of deviation. In this article, we propose causal behavioural profiles as the basis for a consistency notion. These profiles capture essential behavioural information, such as order, exclusiveness, and causality between pairs of activities of a process model. Consistency based on these profiles is weaker than trace equivalence, but can be computed efficiently for a broad class of models. In this article, we introduce techniques for the computation of causal behavioural profiles using structural decomposition techniques for sound free-choice workflow systems if unstructured net fragments are acyclic or can be traced back to S-or T-nets. We also elaborate on the findings of applying our technique to three industry model collections.}, language = {en} } @phdthesis{Smirnov2011, author = {Smirnov, Sergey}, title = {Business process model abstraction}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-60258}, school = {Universit{\"a}t Potsdam}, year = {2011}, abstract = {Business process models are used within a range of organizational initiatives, where every stakeholder has a unique perspective on a process and demands the respective model. As a consequence, multiple process models capturing the very same business process coexist. Keeping such models in sync is a challenge within an ever changing business environment: once a process is changed, all its models have to be updated. Due to a large number of models and their complex relations, model maintenance becomes error-prone and expensive. Against this background, business process model abstraction emerged as an operation reducing the number of stored process models and facilitating model management. Business process model abstraction is an operation preserving essential process properties and leaving out insignificant details in order to retain information relevant for a particular purpose. Process model abstraction has been addressed by several researchers. The focus of their studies has been on particular use cases and model transformations supporting these use cases. This thesis systematically approaches the problem of business process model abstraction shaping the outcome into a framework. We investigate the current industry demand in abstraction summarizing it in a catalog of business process model abstraction use cases. The thesis focuses on one prominent use case where the user demands a model with coarse-grained activities and overall process ordering constraints. We develop model transformations that support this use case starting with the transformations based on process model structure analysis. Further, abstraction methods considering the semantics of process model elements are investigated. First, we suggest how semantically related activities can be discovered in process models-a barely researched challenge. The thesis validates the designed abstraction methods against sets of industrial process models and discusses the method implementation aspects. Second, we develop a novel model transformation, which combined with the related activity discovery allows flexible non-hierarchical abstraction. In this way this thesis advocates novel model transformations that facilitate business process model management and provides the foundations for innovative tool support.}, language = {en} }