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.

Conference Proceedings

Copy reference link   DOI: 10.1109/eScience.2010.12

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.

Export record: Citavi Endnote RIS ISI BibTeX WordXML

Copy reference link   DOI: doi:10.1007/978-3-642-17358-5_73

Abstract: One of the main weaknesses of workflow management systems is their inflexibility regarding process changes. To address this drawback in our work on the BPEL’n’Aspects approach we developed a standards-based mechanism to adapt the control flow of BPEL processes [1]. It uses AOP techniques to non-intrusively weave Web service invocations in terms of aspects into BPEL processes. Aspects can be inserted before, instead or after BPEL elements and that way adaptation of running processes is enabled. In this work we want to present a novel extension of the BPEL’n’Aspects prototype that deals with the compensation of weaved-in aspects in a straight-forward manner. The extension enormously improves the applicability of the approach in real-world scenarios: processes in production need the means to compensate behavior that was inserted into the process in the course of adaptation steps. The ability to compensate weaved-in aspects distinguishes our approach from other existing concepts that introduce AOP techniques to business processes.

Export record: Citavi Endnote RIS ISI BibTeX WordXML

Copy reference link   DOI: doi:10.1007/978-1-4419-9790-6_53

Abstract: Reuse is a common discipline for decreasing software development time and for improving overall quality, independent from the domain. As business processes represent a fundamental asset of an organization, several concepts for enabling reuse during process modeling have been proposed. However, only few concrete examples for reusable process artifacts have been discussed so far. In this paper, we present the concept of process fragments and an example collection of process fragments for illustrating our reuse concept and for showing that it can actually be applied in practice for an easier and faster development of process-based applications. The fragment examples demonstrate different characteristics such fragments may exhibit. We also argue that this work will encourage reuse of process logic in terms of fragments, since it also provides an opportunity to design and develop a process fragment library for collecting process logic explicitly. As technical enabler for the approach we present a prototype called Fragmento.

Export record: Citavi Endnote RIS ISI BibTeX WordXML

Copy reference link   DOI: 10.2316/P.2010.696-049

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.

Export record: Citavi Endnote RIS ISI BibTeX WordXML

Copy reference link   DOI: 10.1145/1774088.1774601

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.

Export record: Citavi Endnote RIS ISI BibTeX WordXML

Copy reference link   DOI: 10.2316/P.2010.696-046

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.

Export record: Citavi Endnote RIS ISI BibTeX WordXML

Copy reference link   DOI: 10.1007/978-3-642-10383-4_43

Abstract: Outsourcing parts of a company’s processes becomes more and more important in a globalized, distributed economy. While architectural styles and technologies such as service-oriented architecture and Web services facilitate the distribution of business process over several departments, enterprises and countries, these business processes still need to comply with various regulations. These regulations can be company regulations, national, or international regulations. When outsourcing IT-functions, enterprises must ensure that the overall regulations are met. Therefore they need evidence from their outsourcing partners that supports the proof of compliance to regulations. Furthermore it must be possible to enforce the adherence to compliance rules at partners. In this paper we introduce so-called compliance interfaces that can be used by customers to subscribe to evidence at a provider and to enforce regulations at a provider. We introduce a general compliance architecture that allows compliance to be monitored and enforced at services deployed in any emerging cloud delivery model.

Export record: Citavi Endnote RIS ISI BibTeX WordXML

Copy reference link   DOI: 10.1109/ICWS.2009.44

Abstract: A fundamental principle of service oriented architectures is the decoupling of service requesters and service providers to enable late binding of services at deployment time or even dynamic binding of services at runtime.This is important in enterprise settings, where different services that implement business functions in critical business processes are dynamically chosen based on availability or price. The same problem also applies to dynamic Grid environments where resources need to be dynamically chosen based on availability and other non-functional properties. The WS-Policy framework describes how policies for both providers and requesters are specified to allow the selection of services based on these policies. Existing approaches, using WS-Policy,have drawbacks by placing the burden of the service selection partially on the client. In this paper we present an extended enterprise service bus that allows service clients to submit policies to which service providers need to comply with together in one message with the service invocation request. We show how these policies are evaluated in the bus and how policies are defined for not only stateless services, but also stateful resources.

Export record: Citavi Endnote RIS ISI BibTeX WordXML

Copy reference link   DOI: 10.1109/ICWS.2009.75

Abstract: The need for flexibility in process-based applications, in particular during their execution, places the demand for enabling adaptability of processes. AOP is considered to be one of the approaches to flexibly switch on and off functionality on per-instance basis in applications during their execution; analogously, this paradigm can be applied in a BPEL environment to enable adaptation of running orchestrations. In the presented approach we strive towards reuse of as much concepts and technology already available in a Web service (WS) environment as possible. We combine standard BPEL, the publish/subscribe paradigm and WS-Policy so that WS operations play the role of aspects with respect to BPEL processes. We present the syntax for such aspects as an extension of the WS-Policy framework. We introduce the architecture of the supporting infrastructure and a prototypical implementation. The approach draws on the combined benefits of service orientation and the AOP paradigm to improve the state-of-the-art techniques for flexibility of service orchestrations in a non-intrusive manner.

Export record: Citavi Endnote RIS ISI BibTeX WordXML

Copy reference link   DOI: doi:10.1007/978-3-540-92666-5_10

Abstract: The Enterprise Service Bus (ESB) is composable middleware that provides applications with services such as message routing and transformation, service composition, dynamic discovery, transactional support, coordination, security features, and others. In an ESB supporting SOAP message exchange, routing algorithms typically follow the sequential SOAP message processing model, where SOAP headers are the main artefacts used to specify the message route and the processing of the payload by intermediaries along that route. This model supports neither alternative nor parallel message routes. In the case of a failing intermediary node this leads to a failure in the message delivery. Moreover, the execution order of services on SOAP message payloads at the intermediaries cannot be prescribed. In this paper, we demonstrate how these deficiencies of the SOAP message processing model can be addressed. We introduce an approach that allows for specifying SOAP message routing logic in terms of BPEL processes. We show that parallel and alternative routes for SOAP messages can be modelled and executed, and the order of services that process a message at intermediaries can be predefined to accommodate the correct processing sequence as required by the concrete application domain. Features like dynamic discovery of services and flexible service composition are leveraged to enable flexible SOAP message routing.

Export record: Citavi Endnote RIS ISI BibTeX WordXML

Copy reference link   DOI: 10.1109/ICIW.2009.79

Abstract: The performance of applications is influenced by the way its operations are grouped into global transactions. This in turn influences the performance of business processes which utilize these applications as implementations of process activities/steps. Stratified transactions, as produced by the stratification approach presented in this paper, is a way to manage a global transaction by combining the more elemental transactions coordinated using the two-phase commit protocol and queued transactions. The stratification approach can be applied for optimally fragmenting workflow-based service compositions and support the out- and in-sourcing scenarios. This paper formally models global transactions and investigates the mechanisms for building an optimally stratified transaction relying on formally defined evaluation criteria. We investigate the applicability of local search algorithms to the optimization of transaction stratification. In particular we consider hill-climbing, simulated annealing, and a novel hybrid method combining both approaches.

Export record: Citavi Endnote RIS ISI BibTeX WordXML

Copy reference link   DOI: 10.1109/ICSC.2008.84

Abstract: Business process management (BPM) aims at supporting the whole life-cycle necessary to deploy and maintain business processes in organisations. Despite its success however, BPM suffers from a lack of automation that would support a smooth transition between the business world and the IT world. We argue that semantic BPM, that is, the enhancement of BPM with semantic Web services technologies, provides further scalability to BPM by increasing the level of automation that can be achieved. We describe the particular SBPM approach developed within the SUPER project and we illustrate how it contributes to enhancing existing BPM solutions in order to achieve more flexible, dynamic and manageable business processes.

Export record: Citavi Endnote RIS ISI BibTeX WordXML

Copy reference link

Abstract: Semantic Business Process Management (SBPM) enhances BPM with semantic technologies in order to increase the degree of automation in the BPM lifecycle and help in bridging the gap between the business and IT views on business processes. In this paper, we describe the architecture of an SBPM System (SBPMS) which supports the whole SBPM lifecycle by providing functionality for process modeling, process configuration, process execution, and process analysis. We analyze the functional requirements of the SBPMS from the business user's and the IT expert's point of view and derive and describe the components of the SBPMS and their key interactions to achieve the required functionalities. We show how existing BPMS components can be extended to use semantics, and describe the integration of new components, such as a Semantic Execution Environment. The presented SBPMS is based on BPMN, BPEL and WSMO technologies.

Export record: Citavi Endnote RIS ISI BibTeX WordXML

Copy reference link

Abstract: This paper estimates the shippers‟ reactions and their economic benefits from a multimodal transport network called LOGOTAKT. For this purpose, an econometric shipper model is being estimated in which the major factor influencing logistics decisions – the balance between warehouse and storage cost – is explicitly taken into account. The functional form is being deduced from the first order condition of Total Logistics Cost function minimization. Transport cost is expressed in form of a complex function depending on order size and the transport distance in order capture the effect of economies of scale in transportation. It is estimated based on empirical data of distribution obtained from two major German companies. Simulations show that the new multimodal transportation system has a significant impact on shipment size distributions changing them in favor of smaller shipments. This leads especially to significant reductions in warehouse costs. Finally, some implications of the analytical results on transport policy are provided: To achieve further modal shift from road to rail, public financial support and the regulatory framework must put railways into the position to consolidate shipments and to exhaust economies of scale.

Export record: Citavi Endnote RIS ISI BibTeX WordXML

Book Chapters

Copy reference link   DOI: doi:10.1007/978-3-319-29582-4_9

Abstract: The adoption of the workflow technology in the eScience domain has contributed to the increase of simulation-based applications orchestrating different services in a flexible and error-free manner. The nature of the provisioning and execution of such simulations makes them potential candidates to be migrated and executed in Cloud environments. The wide availability of Infrastructure-as-a-Service (IaaS) Cloud offerings and service providers has contributed to a raise in the number of supporters of partially or completely migrating and running their scientific experiments in the Cloud. Focusing on Scientific Workflow-based Simulation Environments (SWfSE) applications and their corresponding underlying runtime support, in this research work we aim at empirically analyzing and evaluating the impact of migrating such an environment to multiple IaaS infrastructures. More specifically, we focus on the investigation of multiple Cloud providers and their corresponding optimized and non-optimized IaaS offerings with respect to their offered performance, and its impact on the incurred monetary costs when migrating and executing a SWfSE. The experiments show significant performance improvements and reduced monetary costs when executing the simulation environment in off-premise Clouds.

Export record: Citavi Endnote RIS ISI BibTeX WordXML

Copy reference link   DOI: 10.1007/978-3-642-24755-2_23

Abstract: In the field of natural and engineering science, computer simulations play an increasingly important role to explain or predict phenomena of the real world. Although the software landscape is crucial to support scientists in their every day work, we recognized during our work with scientific institutes that many simulation programs can be considered legacy monolithic applications. They are developed without adhering to known software engineering guidelines, lack an acceptable software ergonomics, run sequentially on single workstations and require tedious manual tasks. We are convinced that SOA concepts and the service composition technology can help to improve this situation. In this paper we report on the results of our work on the service- and service composition-based re-engineering of a legacy scientific application for the simulation of the ageing process in copper-alloyed. The underlying general concept for a distributed, service-based simulation infrastructure is also applicable to other scenarios. Core of the infrastructure is a resource manager that steers server work load and handles simulation data.

Export record: Citavi Endnote RIS ISI BibTeX WordXML

Conference Proceedings

Copy reference link  

Abstract: Expatriation research has predominantly focused on company-backed expatriates (CBEs), who are sent abroad by their employer, and on examining how their levels of on-the-job embeddedness affect their intention to prematurely repatriate. Yet, most expatriates are not CBEs but self-initiated expatriates (SIEs). In this article we hypothesize that for their behavioral and demographic features, CBEs and SIEs differ substantially in their levels of on-the job and off-the-job embeddedness. Moreover, these difference lay ground for moderating effects resulting in different explanations for the repatriation intention of CBEs and SIEs. Drawing on a unique sample of 345 expatriates from 40 different countries we show that while SIEs experience a higher degree of off-the-job embeddedness than CBEs, the two expatriate types do not differ in their levels of on-the-job embeddedness. Also, off-the-job embeddedness is more important for explaining the repatriation intention of CBEs than of SIEs. Most importantly, whereas for SIEs low levels of on-the-job embeddedness increase their intention to repatriate, for CBEs high-not low-levels increase their intention to repatriate. Our findings carry important theoretical implications for research on expatriates and provide managerial implications related to the choice, hiring criteria, and support programs for expatriates.

Export record: Citavi Endnote RIS ISI BibTeX WordXML