The KLU faculty, post-docs, and PhD candidates regularly publish the results of their research in scientific journals. You will find a complete overview of all KLU publications below (e.g. articles in peer-reviewed journals, professional journals, books, working papers, and conference proceedings). Search for relevant terms and keywords, or filter the list by name, year of publication or type of publication. The references include DOIs and abstracts where available, and you can download them to your own reference database or platform. We regularly update the database with new publications.
Andrikopoulos, Vasilios, Santiago Gómez Sáez, Dimka Karastoyanova and Andreas Weiß (2013): Towards Collaborative, Dynamic and Complex Systems (Short Paper): Proceedings of the IEEE 6th International Conference on Service-Oriented Computing and Applications (SOCA 2013), 241-245.
Abstract: Service orientation has significantly facilitated the development of complex distributed systems spanning multiple organizations. However, different application areas approach such systems in domain-specific ways, focusing on particular aspects relevant only for their application types. As a result, we observe a very fragmented landscape of service-oriented systems, which does not enable collaboration across organizations. To address this concern, in this work we introduce the notion of Collaborative, Dynamic and Complex (CDC) systems and position them with respect to existing technologies. In addition, we present how CDC systems are modeled and the steps to provision and execute them. We also contribute an architecture enabling CDC Systems with full life cycle coverage that allows for leveraging service-oriented and Cloud-related technologies.
Vukojevic‐Haupt, Karolina, Dimka Karastoyanova and Frank Leymann (2013): On-demand Provisioning of Infrastructure, Middleware and Services for Simulation Workflows: Proceedings of the IEEE 6th International Conference on Service-Oriented Computing and Applications (SOCA 2013), 91-98.
Abstract: Service orientation is a mainstream paradigm in business applications and gains even greater acceptance in the very active field of eScience. In SOC service binding strategies have been defined to specify the point in time a service can be discovered and selected for use, namely static binding, dynamic binding at deployment or at run time, and dynamic service deployment. The basic assumption in all these strategies is that the software stack and infrastructure necessary to execute the services are already available. While in service-based business applications this is typically a valid assumption in scientific applications it is often not the case. Therefore, in this work we introduce a new binding strategy for services we call on-demand provisioning which entails provisioning of the software stack necessary for the service and subsequent dynamic deployment of the service itself. Towards this goal, we also contribute a middleware architecture that enables the provisioning of the software stack - functionality unavailable in conventional service middlewares. We demonstrate the approach and the capabilities of the middleware and the current state of the implementation of our approach. For this purpose we use an example application from the field of eScience that comprises a scientific workflow management system for simulations.
Rühl, Frederik, Moritz Mörner, Hanno Friedrich and Özhan Özsucu (2013): Assessing the impacts of HGV tolls and transport logistics: Proceedings of the WCTRS Conference on Transportation Research.
Abstract: In this article, basic characteristics of HGV toll systems are described. Based on that, these systems' impacts on entrepreneurial processes and resulting changes in business choices are discussed. Furthermore, a case study on hauliers' reactions on the German HGV toll is presented. The results show that the haulage industry only has to deal with marginal impacts since costs are usually passed along to the customer, this is why operational changes do not seem necessary.
Ottemöller, Ole and Hanno Friedrich (2013): A Concept for Modeling Freight Transport within Supply Networks of the Automotive Industry: Proceedings of the WCTRS Conference on Transportation Research.
Rühl, Frederik, Tobias Freudenreich, Ulrich Berbner, Ole Ottemöller, Hanno Friedrich and Manfred Boltze (2013): Production, Logistics, and Traffic: A Systematic Approach to Understand Interactions: Selected Proceedings of the WCTRS Conference on Transportation Research.
Abstract: Desicion-makers in and around today's supply chains are facing tough every day. However, when making decisions, they rarely consider what effects their desicions cause upon other participants of the supply chain or traffic management. This is mostly due to the lack of appropriate tools which help indicating the possible effects. Such tools are necessary to tackle the inherent complexity of the whole supply chain system. This paper describes how to construct and design such a tool for this interdisciplinary environment, called an Interdisciplinary Decision Map (IDM). The IDM is a powerful tool to visualise complex relationships, while at the same time retaining usability by showing relevant information only. We show how tu use a specific instance of an IDM to facilitate a better understanding to the underlying processes of other supply chain participants. The soundness of our approach is backed by findings from an interdisciplinary research project.
Münzberg, Thomas, Ulrich Berbner, Hanno Friedrich, Tina Comes, Wendelin Gross, Frank Schultmann and Hans-Christian Pfohl (2013): Decision Support for Critical Infrastructure Disruptions: An Integrated Approach to Secure Food Supply, in: Friedrich, Frank, Stephen Fortier, Jutta Geldermann and Tim Müller (ed.): Proceedings of the 10th International Conference on Information Systems for Crisis Response and Management (ISCRAM), 312-316.
Abstract: Supplies of food and water are essential in disaster management, particularly in the very early chaotic phases when demand and available resources are highly uncertain, information systems are disrupted, and communication between communities, food suppliers, retail and emergency authorities is difficult. As many actors and organisations are involved in ever more complex food supply chains, cooperation and collaboration are vital for efficient and effective disaster management. To support decision-makers facing these problems, this paper introduces a scenario-based approach that integrates simulation of disruptions in food supply chains, and qualitative expert assessment to develop consistent scenarios that show the consequences of different strategies. To choose the best individual measures for all relevant actors and to compare it with the best overall strategy approaches from multi-criteria decision analysis are used.
Schumm, David, Dimitrios Dentsas, Michael Hahn, Dimka Karastoyanova, Frank Leymann and Mirko Sonntag (2012): Web service composition reuse through shared process fragment libraries, in: Brambilla, Marco, Takehiro Tokuda and Robert Tolksdorf (ed.): Proceedings of the 12th international conference on Web Engineering (ICWE'12 ), 498-501.
Abstract: More and more application functionality is provided for use over corporate and public networks. Standardized technology stacks, like Web services, provide abstraction from the internal implementation. Coarse-grained units of Web service composition logic can be made reusable by capturing it as ‘process fragment'. Such fragments can be shared over the Web to simplify and accelerate development of process-based service compositions. In this demonstration, we present a framework consisting of an Eclipse-based process design environment that is integrated with a Web-based process fragment library. The framework enables extracting process fragments, publishing and sharing them on the Web, as well as search, retrieval, and their reuse in a given process. Process fragments can be shared with others using a Web frontend or through a plug-in within the process design environment which is building on Web service technology.
Kopp, Oliver, Uwe Breitenbucher, Michael Reiter and Dimka Karastoyanova (2012): Quality of data driven simulation workflows: Proceedings of the 8th IEEE International Conference on eScience (eScience 2012), 1-8.
Abstract: Simulations are characterized by long running calculations and complex data handling tasks accompanied by non-trivial data dependencies. The workflow technology helps to automate and steer such simulations. Quality of Data frameworks are used to determine the goodness of simulation data, e.g., they analyze the accuracy of input data with regards to the usability within numerical solvers. In this paper, we present generic approaches using evaluated Quality of Data to steer simulation workflows. This allows for ensuring that the predefined requirements such as a precise final result or a short execution time will be met even after the execution of simulation workflow has been started. We discuss mechanisms for steering a simulation on all relevant levels - workflow, service, algorithms, and define a unifying approach to control such workflows. To realize Quality of Data-driven workflows, we present an architecture realizing the presented approach and a WS-Policy-based language to describe Quality of Data requirements and capabilities.
Nowak, Alexander, Dimka Karastoyanova, Frank Leymann, Andrej Rapoport and David Schumm (2012): Flexible Information Design for Business Process Visualizations, in: Leu, Jenq-Shiou (ed.): Proceedings of the Fifth IEEE International Conference on Service-Oriented Computing and Applications (SOCA2012).
Abstract: Profound understanding of business processes is a key success factor for Business Process Management (BPM). As more and more analytical information like runtime data from process execution or statistical data from business intelligence are available, the problem of business process complexity becomes apparent. Process-relevant information needs to be provided as fast as possible while considering easy and fast interpretation and dynamic changes in stakeholders' demands. The static and use-case specific creation or modification of process visualizations shown in current approaches and tools, however, is complex, time consuming, inflexible and thus costly. To address these shortcomings, we introduce a template-based approach that decouples the creation of visualization templates from concrete process visualizations. The binding of customization points of visualization templates to analytical process information is supported by a graphical editor that enables customization of visualizations in a fast and flexible manner. Moreover, due to the separation of concerns, our approach improves the usability of process visualizations because templates may be created by graphic experts independently from specific visualization demands. The feasibility of our concept is demonstrated by a prototypical implementation.
Karastoyanova, Dimka, Dimitrios Dentsas, David Schumm, Mirko Sonntag, Lina Sun and Vukojevic (2012): Service-based integration of human users in workflow-driven scientific experiments: Proceedings of the 8th IEEE International Conference on eScience (eScience 2012).
Abstract: The use of information technology in research and practice leads to increased degree of automation of tasks and makes scientific experiments more efficient in terms of cost, speed, accuracy, and flexibility. Scientific workflows have proven useful for the automation of scientific computations. However, not all tasks of an experiment can be automated. Some decisions still need to be made by human users, for instance, how an automated system should proceed in an exceptional situation. To address the need for integration of human users in such automated systems, we propose the concept of Human Communication Flows, which specify best practices about how a scientific workflow can interact with a human user. We developed a human communication framework that implements Communication Flows in a pipes-and-filters architecture and supports both notifications and request-response interactions. Different Communication Services can be plugged into the framework to account for different communication capabilities of human users. We facilitate the use of Communication Flows within a scientific workflow by means of reusable workflow fragments implementing the interaction with the framework.
Wagner, Sebastian, Christoph Fehling, Dimka Karastoyanova and David Schumm (2012): State propagation-based monitoring of business transactions, in: Leu, Jenq-Shiou (ed.): Proceedings of the Fifth IEEE International Conference on Service-Oriented Computing and Applications (SOCA2012).
Abstract: Business analysts want to monitor the status of their business goals in a business-centric manner, without any knowledge of the actual implementation artifacts that contribute to achieve these goals. Business transactions are one means to represent business goals and requirements. A business transaction is typically implemented by a choreography of different parties contributing to the accomplishment of a common agreement. To meet the constantly changing requirements for all parties in a business transaction choreographies often have to be adapted (e.g. based on the capabilities of different execution environments). The resulting challenge is that the execution state of a choreography executed on several locations has to be propagated to the business analyst to enable monitoring of the (adapted) business transaction. For this purpose we introduce a meta-model and state model of business transactions. Based on these models, we introduce a two-stage monitoring approach involving state propagation of the execution status of the adapted choreography to the original choreography and from there to the business transaction.
Sonntag, Mirko, Michael Hahn and Dimka Karastoyanova (2012): Mayflower ‐ Explorative Modeling of Scientific Workflows with BPEL, in: Lohmann, Niels and Simon Moser (ed.): Proceedings of the Demonstration Track of the 10th International Conference on Business Process Management (BPM 2012), CEUR Workshop Proceedings, 2012, 45-50.
Abstract: Abstract Using workflows for scientific calculations, experiments and simulations has been a success story in many cases. Unfortunately, most of the existing scientific workflow systems implement proprietary, non-standardized workflow languages, not taking advantage of the achievements of the conventional business workflow technology. It is only natural to combine these two research branches in order to harness the strengths of both. In this demonstration, we present Mayflower, a workflow environment that enables scientists to model workflows on the fly using extended business workflow technology. It supports the typical trial-and-error approach scientists follow when developing their experiments, computations or simulations and provides scientists with all crucial characteristics of the workflow technology. Additionally, beneficial to the business stakeholders, Mayflower brings additional simplification in workflow development and debugging.
Friedrich, Hanno, Steffen Despotov, Li Zhang and Patrick Kroner (2012): Measures of Supply Chain Risk Management: Proceedings of the 9th International Meeting on Logistics Research.
Reiter, Michael, Uwe Breitenbücher, Schahram Dustdar, Dimka Karastoyanova and Frank Leymann (2011): A Novel Framework for Monitoring and Analyzing Quality of Data in Simulation Workflows: Proceedings of the IEEE Seventh International Conference on eScience (eScience2011), 105-112.
Abstract: In recent years scientific workflows have been used for conducting data-intensive and long running simulations. Such simulation workflows have processed and produced different types of data whose quality has a strong influence on the final outcome of simulations. Therefore being able to monitor and analyze quality of this data during workflow execution is of paramount importance, as detection of quality problems will enable us to control the execution of simulations efficiently. Unfortunately, existing scientific workflow execution systems do not support the monitoring and analysis of quality of data for multi-scale or multi-domain simulations. In this paper, we examine how quality of data can be comprehensively measured within workflows and how the measured quality can be used to control and adapt running workflows. We present a quality of data measurement process and describe a quality of data monitoring and analysis framework that integrates this measurement process into a workflow management system.
Reimann, Peter, Michael Reiter, Holger Schwarz, Dimka Karastoyanova and Frank Leymann (2011): SIMPL - A Framework for Accessing External Data in Simulation Workflows, in: Theo Härder, Wolfgang Lehner, Bernhard Mitschang, Harald Schöning and Holger Schwarz (ed.): Datenbanksysteme für Business, Technologie und Web (BTW), Proceedings of the 14. Fachtagung des GI-Fachbereichs "Datenbanken und Informationssysteme (DBIS),, 534-553.
Abstract: Adequate data management and data provisioning are among the most important topics to cope with the information explosion intrinsically associated with simulation applications. Today, data exchange with and between simulation applications is mainly accomplished in a file - style manner. These files show proprietary formats and have to be transformed according to the specific needs of simulation applications. Lots of effort has to be spent to find appropriate data sources and to specify and implement data transformations. In this paper, we present SIMPL – an extensible framework that provides a generic and consolidated abstraction for data management and data provisioning in simulation workflows. We introduce extensions to workflow languages and show how they are used to model the data provisioning for simulation workflows based on data management patterns. Furthermore, we show how the framework supports a uniform access to arbitrary external data in such workflows. This removes the burden from engineers and scientists to specify low-level details of data management for their simulation applications and thus boosts their productivity.
Sonntag, Mirko and Dimka Karastoyanova (2011): Enforcing the Repeated Execution of Logic in Workflows, in: Santos, Maribel Y. and Vagan Terziyan (ed.): Proceedings of the first International Conference on Business Intelligence and Technology (BUSTECH2011), 20-25.
Abstract: The repeated execution of workflow logic is a feature needed in many situations. Repetition of activities can be modeled with workflow constructs (e.g., loops) or external workflow configurations, or can be triggered by a user action during workflow execution. While the first two options are state of the art in the workflow technology, the latter is currently insufficiently addressed in literature and practice. We argue that a manually triggered rerun operation enables both business users and scientists to react to unforeseen problems and thus improves workflow robustness, allows scientists steering the convergence of scientific results, and facilitates an explorative workflow development as required in scientific workflows. In this paper, we therefore formalize operations for the repeated enactment of activities—for both iteration and re-execution. Starting point of the rerun is an arbitrary, manually selected activity. Since we define the operations on a meta-model level, they can be implemented for different workflow languages and engines.
Sonntag, Mirko, Katharina Görlach, Dimka Karastoyanova, Frank Leymann, Polina Malets and David Schumm (2011): Views on Scientific Workflows, in: Grabis, Janis and Marite Kirikova (ed.): 10th International Conference on Perspectives in Business Informatics Research (BIR 2011), 321-335.
Abstract: Workflows are becoming more and more important in e-Science due to the support they provide to scientists in computer simulations, experiments and calculations. Our experiences with workflows in this field and the literature show that scientific workflows consist of a large number of related information. This information is difficult to deal with in a single perspective and has changing importance to scientists in the different workflow lifecycle phases. In this paper we apply viewing techniques known from business process management to (service-based) scientific workflows to address these issues. We describe seven of the most relevant views and point out realization challenges. We argue that the selected views facilitate the handling of workflows to scientists and add further value to scientific workflow systems. An implementation of a subset of the views based on Web services and BPEL shows the feasibility of the approach. The presented work has the goal to increase additionally the acceptance of the workflow technology in e-Science.
Schumm, David, Jiayang Cai, Christoph Fehling, Dimka Karastoyanova, Frank Leymann and Monika Weidmann (2011): Composite Process View Transformation, in: Huemer, Christian and Thomas Setzer (ed.): E-Commerce and Web Technologies: Proceedings of the 12th International Conference, EC-Web 2011, 52-63.
Abstract: The increasing complexity of processes used for design and execution of critical business activities demands novel techniques and technologies. Process viewing techniques have been proposed as means to abstract from details, summarize and filter out information, and customize the visual appearance of a process to the need of particular stakeholders. However, composition of process view transformations and their provisioning to enable their usage in various scenarios is currently not discussed in research. In this paper, we present a lightweight, service-oriented approach to compose modular process view transformation functions to form complex process view transformations which can be offered as a service. We introduce a concept and an architectural framework to generate process view service compositions automatically with focus on usability. Furthermore, we discuss key aspects regarding the realization of the approach as well as different scenarios where process view services and their compositions are needed.
Sonntag, Mirko and Dimka Karastoyanova (2011): Compensation of Adapted Service Orchestration Logic in BPEL’n’Aspects, in: Hutchison, David, Farouk Toumani, Stefanie Rinderle-Ma, Gerhard Weikum, Moshe Y. Vardi, Doug Tygar, Demetri Terzopoulos, Madhu Sudan, Bernhard Steffen, C. Pandu Rangan, Oscar Nierstrasz, Moni Naor, John C. Mitchell, Friedemann Mattern, Jon M. Kleinberg, Josef Kittler, Takeo Kanade and Karsten Wolf (ed.): Proceedings of the 9th International Conference Business Process Management (BPM 2011), 413-428.
Abstract: BPEL’n’Aspects is a non-intrusive mechanism for adaptation of control flow of BPEL processes based on the AOP paradigm. It relies on Web service standards to weave process activities in terms of aspects into BPEL processes. This paper is a logical continuation of the BPEL’n’Aspects approach. Its main objective is to enable compensation of weaved-in Web service invocations (activities) in a straightforward manner. We present (1) requirements on a mechanism for compensation of weaved-in process activities; (2) the corresponding concepts and mechanisms to meet these requirements; (3) an example scenario to show the applicability of the approach; and (4) a prototypical implementation to prove the feasibility of the solution. This work represents an improvement in the applicability of this particular adaptation approach since processes in production need the means to compensate actions that are included into processes as result of an adaptation step, too. The concept is generic and hence can also be used by other approaches that adapt control flow.
Friedrich, Hanno and Ole Ottemöller (2011): Transferring Methods from Social Dynamic Network Analysis to Freight Transportation: Proceedings of the 16th International Conference of Hong Kong Society for Transportation Studies.
Sonntag, Mirko, Dimka Karastoyanova and Ewa Deelman (2010): Bridging the Gap between Business and Scientific Workflows: Humans in the Loop of Scientific Workflows: Proceedings of the IEEE Sixth International Conference on e-Science, 206-213.
Abstract: Due to their different target applications business and scientific workflow systems provide different sets of features to their users. Significant amount of research is currently being done to employ the business workflow technology in the scientific domain. This usually means extending the workflow language and thus the modeling tool and execution engine. In this paper we aim to bring business and scientific workflows together in order to exploit the advantages of both. We explore the interplay between business and scientific workflows in the context of human interactions with the management of workflow execution. We present an approach and implementation based on BPEL and Pegasus and show that the approach can be beneficial to scientists.
Friedrich, Hanno (2010): Simulation of Logistic Structures in Food Retailing to Estimate Demand for Freight Transportation: Proceedings of the WCTRS Conference on Transportation Research 2010.
Sonntag, Mirko and Dimka Karastoyanova (2010): Next Generation Interactive Scientific Experimenting Based On the Workflow Technology, in: Alhajj, R. S., V.C.M. Leung, R. Petela, M. Saif and R. Thring (ed.): Proceedings of the 21st IASTED Technology Conferences: World Modelling and Simulation Forum (WMSF).
Abstract: In this paper we explore to what extent the conventional workflow technology and service-oriented architecture (SOA) principles can be applied to support scientist in their experiments. Based on the requirements imposed on systems for scientific computing, e-Science and simulations, and an extended workflow life cycle we introduce the architecture of an interactive system that reuses the conventional workflow technology. We advocate the realization of this workflow system with advanced adaptation and monitoring features because we identified that modeling of scientific applications and simulations can only be done the scientists way if the traditional workflow modeling as well as design and run time adaptation are combined in a user-friendly solution.
Wetzstein, Branimir, Dimka Karastoyanova, Oliver Kopp, Frank Leymann and Daniel Zwink (2010): Cross-organizational process monitoring based on service choreographies, in: Shin, Dongwan (ed.): Proceedings of the 25th Annual ACM Symposium on Applied Computing (SAC 2010), 2485-2490.
Abstract: Business process monitoring in the area of service oriented computing is typically performed using business activity monitoring technology in an intra-organizational setting. Due to outsourcing and the increasing need for companies to work together to meet their joint customer demands, there is a need for monitoring of business processes across organizational boundaries. Thereby, partners in a choreography have to exchange monitoring data, in order to enable process tracking and evaluation of process metrics. In this paper, we describe an event-based monitoring approach based on BPEL4Chor service choreography descriptions. We show how to define monitoring agreements specifying events each partner in the choreography has to provide. We distinguish between resource events and complex events for calculation of process metrics using complex event processing technology. We present our implementation and evaluate the concepts based on a scenario.
Sonntag, Mirko, Katharina Görlach, Dimka Karastoyanova and Natalia Currle-Linde (2010): Towards Simulation Workflows with BPEL: Deriving Missing Features from GriCoL, in: Alhajj, R. S., V.C.M. Leung, R. Petela, M. Saif and R. Thring (ed.): Proceedings of the 21st IASTED Technology Conferences: World Modelling and Simulation Forum (WMSF).
Abstract: In this paper, we investigate the suitability of the general purpose workflow language BPEL to create executable simulation workflows. We therefore compare BPEL to GriCoL, a graphical language with proven applicability for simulation workflows in Grid environments. We discover a number of incomparable concepts in the two languages. On the one hand, BPEL’s unique features in comparison to GriCoL reveal the rationale behind the approach of using BPEL as basis for a simulation workflow language. On the other hand, based on the features of GriCoL, we are able to discuss how to extend BPEL in order to increase its expressiveness for simulation workflows.