25,757 research outputs found
Composition and Self-Adaptation of Service-Based Systems with Feature Models
The adoption of mechanisms for reusing software in pervasive systems has not yet become standard practice. This is because the use of pre-existing software requires the selection, composition and adaptation of prefabricated software parts, as well as the management of some complex problems such as guaranteeing high levels of efficiency and safety in critical domains. In addition to the wide variety of services, pervasive systems are composed of many networked heterogeneous devices with embedded software. In this work, we promote the safe reuse of services in service-based systems using two complementary technologies, Service-Oriented Architecture and Software Product Lines. In order to do this, we extend both the service discovery and composition processes defined in the DAMASCo framework, which currently does not deal with the service variability that constitutes pervasive systems. We use feature models to represent the variability and to self-adapt the services during the composition in a safe way taking context changes into consideration. We illustrate our proposal with a case study related to the driving domain of an Intelligent Transportation System, handling the context information of the environment.Work partially supported by the projects TIN2008-05932,
TIN2008-01942, TIN2012-35669, TIN2012-34840 and CSD2007-0004 funded by
Spanish Ministry of Economy and Competitiveness and FEDER; P09-TIC-05231 and
P11-TIC-7659 funded by Andalusian Government; and FP7-317731 funded by EU. Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec
Optimizing Computation of Recovery Plans for BPEL Applications
Web service applications are distributed processes that are composed of
dynamically bounded services. In our previous work [15], we have described a
framework for performing runtime monitoring of web service against behavioural
correctness properties (described using property patterns and converted into
finite state automata). These specify forbidden behavior (safety properties)
and desired behavior (bounded liveness properties). Finite execution traces of
web services described in BPEL are checked for conformance at runtime. When
violations are discovered, our framework automatically proposes and ranks
recovery plans which users can then select for execution. Such plans for safety
violations essentially involve "going back" - compensating the executed actions
until an alternative behaviour of the application is possible. For bounded
liveness violations, recovery plans include both "going back" and "re-planning"
- guiding the application towards a desired behaviour. Our experience, reported
in [16], identified a drawback in this approach: we compute too many plans due
to (a) overapproximating the number of program points where an alternative
behaviour is possible and (b) generating recovery plans for bounded liveness
properties which can potentially violate safety properties. In this paper, we
describe improvements to our framework that remedy these problems and describe
their effectiveness on a case study.Comment: In Proceedings TAV-WEB 2010, arXiv:1009.330
Requirements and Tools for Variability Management
Explicit and software-supported Business Process Management has become the core infrastructure of any medium and large organization that has a need to be efficient and effective. The number of processes of a single organization can be very high, furthermore, they might be very similar, be in need of momentary change, or evolve frequently. If the ad-hoc adaptation and customization of processes is currently the dominant way, it clearly is not the best. In fact, providing tools for supporting the explicit management of variation in processes (due to customization or evolution needs) has a profound impact on the overall life-cycle of processes in organizations. Additionally, with the increasing adoption of Service-Oriented Architectures, the infrastructure to support automatic reconfiguration and adaptation of business process is solid.
In this paper, after defining variability in business process management, we consider the requirements for explicit variation handling for (service based) business process systems. eGovernment serves as an illustrative example of reuse. In this case study, all local municipalities need to implement the same general legal process while adapting it to the local business practices and IT infrastructure needs. Finally, an evaluation of existing tools for explicit variability management is provided with respect to the requirements identified.
Supporting 'design for reuse' with modular design
Engineering design reuse refers to the utilization of any knowledge gained from the design activity to support future design. As such, engineering design reuse approaches are concerned with the support, exploration, and enhancement of design knowledge prior, during, and after a design activity. Modular design is a product structuring principle whereby products are developed with distinct modules for rapid product development, efficient upgrades, and possible reuse (of the physical modules). The benefits of modular design center on a greater capacity for structuring component parts to better manage the relation between market requirements and the designed product. This study explores the capabilities of modular design principles to provide improved support for the engineering design reuse concept. The correlations between modular design and 'reuse' are highlighted, with the aim of identifying its potential to aid the little-supported process of design for reuse. In fulfilment of this objective the authors not only identify the requirements of design for reuse, but also propose how modular design principles can be extended to support design for reuse
Implementing a map based simulator for the location API for J2ME
The Java Location API for J2METM integrates generic positioning and orientation data with
persistent storage of landmark objects. It can be used to develop location based service
applications for small mobile devices, and these applications can be tested using simulation
environments. Currently the only simulation tools in the public domain are proprietary
mobile device simulators that are driven by GPS data log files, but it is sometimes useful to
be able to test location based services using interactive map-based tools. In addition, we
may need to experiment with extensions and changes to the standard API to support
additional services, requiring an open source environment. In this paper we describe the
implementation of an open source map-based simulation tool compatible with other
commonly used development and deployment tools
Towards Management of Complex Service Compositions
Many companies offer physical products combined with
on-line services. For example, product configuration, ordering, order tracking, and payments can be done on-line. The service part of the total offering (the composition) is typically composed of services offered by providers where performance of both the composition (provided by the company) and the input services (obtained from providers) is governed by service level agreements (SLAs). The goal of our approach is to diagnose the performance of an on-line service composition in terms of the performance of on-line input services, with respect to the performance indicators mentioned in the SLAs, and to do this in real-time.
Classical SLA monitoring techniques are batch-oriented and are not usable in the highly dynamic environment of Web service provision, where provider relations may change even during service delivery. Our techniques use real-time analysis of log files to trace and diagnose performance on-the-fly. Current Web service monitoring techniques do not relate a composite service to its components, as needed to provide diagnostic information. Furthermore, current approaches do not take into account that the dependency of a composition on its components varies for different attributes (such as cost and response time). In this paper we propose to extend our previous research in this area by lifting a number of simplifying assumptions to make the approach applicable in real-life, and by extending our study to frequently used SLAs in practice
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