Context-Aware Computation Offloading for Mobile Cloud Computing: Requirements Analysis, Survey and Design Guideline

AbstractAlong with the rise of mobile handheld devices the resource demands of respective applications grow as well. However, mobile devices are still and will always be limited related to performance (e.g., computation, storage and battery life), context adaptation (e.g., intermittent connectivity, scalability and heterogeneity) and security aspects. A prominent solution to overcome these limita- tions is the so-called computation offloading, which is the focus of mobile cloud computing (MCC). However, current approaches fail to address the complexity that results from quickly and constantly changing context conditions in mobile user scenarios and hence developing effective and efficient MCC applications is still challenging. Therefore, this paper first presents a list of re- quirements for MCC applications together with a survey and classification of current solutions. Furthermore, it provides a design guideline for the selection of suitable concepts for different classes of common cloud-augmented mobile applications. Finally, it presents open issues that developers and researchers should be aware of when designing their MCC-approach

Context-based Cooperation in Mobile Business Environments – Managing the Distributed Execution of Mobile Processes

Realistic requirements of mobile business applications often exceed the capabilities of their respective local environments. In order to overcome such restrictions of specific mobile devices, services, and resources, this contribution introduces the concept of context-based cooperation. It is based on mobile processes which enable applications to cross boundaries of individual systems and thereby allow combining both mobile and stationary resources in order to realize highly dynamic individual applications. This contribution presents an approach for realizing context-based cooperation built upon on a respective context management infrastructure and execution environment. It also identifies specific requirements and proposes related enhancements for mobile business applications

A Reputation-Based Approach to Self-Adaptive Service Selection

Service-orientation provides concepts and tools for flexible composition and management of largescale distributed software applications. The automated run-time management of such loosely coupled software systems, however, poses still major challenges and is therefore an active research area, including the use of novel computing paradigms. In this context, the dynamic and adaptive selection of best possible service providers is an important task, which can be addressed by an appropriate middleware layer that allows considering different service quality aspects when managing the adaptive execution of distributed service workflows dynamically. In such an approach, service consumers are enabled to delegate the adaptive selection of service providers at run-time to the execution infrastructure. The selection criteria used are based on the cost of a service provision and the continuous, dynamic evaluation of reputations of providers, i.e. maintained track records of meeting the respective service commitments. This paper discusses the design and operating principle of such an automatic service selection middleware extension. Its ability to balance different quality criteria for service selection, such as service cost vs. the reliability of provision, is empirically evaluated based on a multi-agent platform approach

Kundenorientierte Aspekte der Konzeption von Online-Shops

Aus der Einleitung: 'Online-Shops (e-Shops) haben sich innerhalb der letzten Jahre im Business-to-Consumer Bereich des Electronic Commerce als das dominierende Geschäftsmodell herausgebildet. Sowohl bei der Konzeption als auch bei der Einführung von Online-Shops wird jedoch oft nur explorativ vorgegangen. Die Realisierung eines Online-Shops wird vorwiegend als die Transition der herkömmlichen Verkaufsmittel in das Medium Internet aufgefasst. Dabei finden sowohl die Eigenheiten des neuen Mediums als auch die Anforderungen durch die Gemeinschaft der Kunden nicht ausreichend Berücksichtigung. Der vorliegende Beitrag stellt kundenorientierte Aspekte der Konzeption von Online-Shops vor, die eine bessere Modellierung der Anforderungen gewährleisten, die Auswirkungen der Integration von Online-Shops in die Datenverarbeitung des Unternehmens berücksichtigen und kundenbezogene Kooperationsaspekte mit einbeziehen

Systematically Engineering Self-Organizing Systems: The SodekoVS Approach

Self-organizing systems promise new software quality attributes that are very hard to obtain using standard software engineering approaches. In accordance with the visions of e.g. autonomic computing and organic computing, self-organizing systems promote self-adaptability as one major property helping to realize software that can manage itself at runtime. In this respect, self-adaptability can be seen as a necessary foundation for realizing e.g. self* properties such as self-configuration or self-protection. However, the systematic development of systems exhibiting such properties challenges current development practices. The SodekoVS project addresses the challenge to purposefully engineer adaptivity by proposing a new approach that considers the system architecture as well as the software development methodology as integral intertwined aspects for system construction. Following the proposed process, self-organizing dynamics, inspired by biological, physical and social systems, can be integrated into applications by composing modules that distribute feedback control structures among system entities. These compositions support hierarchical as well as completely decentralized solutions without a single point of failure. This novel development conception is supported by a reference architecture, a tailored programming model as well as a library of ready to use self-organizing patterns. The key challenges, recent research activities, application scenarios as well as intermediate results are discussed

Keeping Pace with Changes - Towards Supporting Continuous Improvements and Extensive Updates in Manufacturing Automation Software

Every long-term used software system ages. Even though intangible goods like software do not degenerate in the proper sense, each software system degenerates in relation to the everlasting changes of requirements, usage scenarios and environmental conditions. Accordingly, operational software is commonly situated in a continuous evolution process in which manually conducted modifications and adaptations try to preserve or reinforce its quality. Unfortunately, such an unmanaged evolution inevitably leads to a discrepancy between the obsolete originally documented requirements and the updated software itself. For this reason, our contribution presents a coherent vision of an anti-aging cycle that preserves (non-)functional requirements as explicit runtime artefacts. The fulfilment of these requirements is validated based on conditionally triggered online test cases. In order to achieve an enhanced semantic test coverage, these test cases are adapted by monitoring, analysing and learning typical system behaviours. To explain our vision in more detail and demonstrate the benefit of a managed software evolution, our anti-aging cycle is exemplarily applied on the domain of manufacturing automation