The quality of service (QoS) of enterprise distributedreal-time and embedded (DRE) systems can degrade under certain operating conditions and system architectures. This paper provides two contributions to research on...
详细信息
ISBN:
(纸本)0769525466
The quality of service (QoS) of enterprise distributedreal-time and embedded (DRE) systems can degrade under certain operating conditions and system architectures. This paper provides two contributions to research on model-driven development (MDD) tools and methods that help identify and rectify these QoS problems in component-based enterprise DRE systems. First, we show how MMD tools can be used to simplify and automate the evaluation of component-based DRE systems to identify QoS problems. Second, we show how MMD tools can be used to specify alternative QoS polices for component-based DRE systems and synthesize metadata automatically to simplify system (re)configurations that rectify QoS problems. We illustrate our MDD tools on a case study of multi-layer resource management services for shipboard computing systems that automate many aspects of power, navigation, command and control, and tactical operations.
Many interesting applications using mobile ad-hoc networks are possible if quality-of-service (QoS) can be effectively supported. Towards that end, this paper proposes a method based on providing a pool of backup path...
详细信息
Many interesting applications using mobile ad-hoc networks are possible if quality-of-service (QoS) can be effectively supported. Towards that end, this paper proposes a method based on providing a pool of backup paths that can be used if the primary path can no longer support the required level of QoS. Such a capability is especially important for mobile ad-hoc networks because intermediate nodes (within routing paths) can move around in such networks. Route maintenance and switchover should also be performed in an efficient manner. This is accomplished with the help of a method referred to as pseudo-distance routing
This paper provides a series of lessons learned with respect to using performance modeling and analysis techniques on designs of object-oriented software systems. Specifically it focuses on the application of the Unif...
详细信息
This paper provides a series of lessons learned with respect to using performance modeling and analysis techniques on designs of object-oriented software systems. Specifically it focuses on the application of the Unified Modeling Language (UML) profile for schedulability performance, and time (SPT) paired with statistical simulation and coloured Petri nets (CPNs). The experiences captured in this paper are based on observations from an empirical study evaluating these techniques
This paper presents the architecture and conception of an organic middleware based on the yet existing, not organic middleware OSA+. We show new general design principles helping to establish the self-organizing middl...
详细信息
This paper presents the architecture and conception of an organic middleware based on the yet existing, not organic middleware OSA+. We show new general design principles helping to establish the self-organizing middleware which can be used for totally different applications like robotics, warehouse management and the planning of a person's daily routine
Embedded real-time systems are becoming increasingly complex due to ever increasing size and functionality so that complexity management is of growing importance, especially in dependable hard real-time systems develo...
详细信息
Embedded real-time systems are becoming increasingly complex due to ever increasing size and functionality so that complexity management is of growing importance, especially in dependable hard real-time systems development, where errors caused by complexity can have fatal consequences. This paper systematically characterizes different kinds of complexity: system-level complexity, component interface complexity, and component implementation complexity. The effects of the different kinds of complexity are described and it is explained why minimizing system-level complexity should be a principal goal of any distributed embedded real-time systems architecture. The concept of system-level components is introduced as a solution to the problem of system-level complexity during the integration process
A distributed Virtual Environment (DVE) system offers a computer-generated virtual world in which individuals located at different places in the physical world can interact with one another. In order to achieve real-t...
详细信息
A distributed Virtual Environment (DVE) system offers a computer-generated virtual world in which individuals located at different places in the physical world can interact with one another. In order to achieve real-time response for a large user base, DVE systems need to have a scalable architecture. In this paper, we present the design of a grid-enabled serviceoriented framework for facilitating the construction of scalable DVE systems on computing grids. A servicecomponent called "gamelet" is proposed, whose distinctive mark is its high mobility for supporting dynamic load sharing. We propose a gamelet migration protocol which can ensure the transparency and efficiency of gamelet migration, and an adaptive gamelet load-balancing (AGLB) algorithm for making gamelet redistribution decisions at runtime. The algorithm considers both the synchronization costs of the DVE system and network latencies inherent in the grid nodes. The activities of the users and the heterogeneity of grid resources are also considered in order to carry out load sharing more effectively. We evaluate the performance of the proposed mechanisms through a multiplayer online game prototype implemented using the Globus toolkit. The results show that our approach can achieve faster response times and higher throughputs than some existing approaches.
object-oriented software development practices are being rapidly adopted within increasingly complex systems, including reactive, real-time and concurrent system applications. While data modeling is performed very wel...
详细信息
object-oriented software development practices are being rapidly adopted within increasingly complex systems, including reactive, real-time and concurrent system applications. While data modeling is performed very well under current object-oriented development practices, behavioral modeling necessary to capture critical information in real-time, reactive, and concurrent systems is often lacking. Addressing this deficiency, we offer an approach for modeling and analyzing concurrent object-oriented software designs through the use of behavioral patterns captured through colored Petri nets
Web services provide the potential to offer interoperability of distributed business-to-business application integration between autonomous organisations, regardless of platforms, operating systems or languages. For b...
详细信息
Web services provide the potential to offer interoperability of distributed business-to-business application integration between autonomous organisations, regardless of platforms, operating systems or languages. For both user and vendor organisations, this raises immediate problems of trust, security, privacy and prevention of malicious attacks. Until these problems are addressed and solved properly, the use of Web services will be severely restricted because no-one will trust them. We describe in this paper a service-oriented architecture and an attack-tolerant information retrieval (ATIR) service which tackles certain classes of privacy problems. In particular, we address the problem of protecting a user against malicious attacks upon an information service when the user retrieves some information from the service. Although there have been many theoretical solutions to certain aspects of this problem, the results have yet to be adapted to real systems. We report our experience of integrating the ATIR service with Taverna, a popular workflow system used amongst the UK e-science/grid computing community, to support secure information retrieval in the biology context. Performance studies show that the overhead of ATIR server-side processing is trivial (<5%) in comparison with the total processing time of the integrated Taverna. Our experimental results also show that the major processing overhead is caused by the Taverna enactor operations which consume no less than 50% of the total processing time
In a real-timedistributedcomputing environment, security is critical to protect the system from unauthorized access especially since such systems are being used in time critical applications. Access control mechanis...
详细信息
In a real-timedistributedcomputing environment, security is critical to protect the system from unauthorized access especially since such systems are being used in time critical applications. Access control mechanisms have been introduced during the last several decades and have offered a basic and powerful means for enforcing security. In this paper, we examine the concepts of the TMO (time triggered message triggered object) scheme that provides guaranteed real-timeservices in a distributedobjectcomputing environment. We also examine access control mechanisms; such as the traditional model, the RBAC (role-based access control) model and the UCON (usage control) model. The main contribution of this paper is applying the traditional, RBAC and UCON models to the TMO scheme in order to provide a secure real-timedistributed environment
The TMO (time-triggered message-triggered object) model is a well-known real-timeobject model for distributedtimeliness computing. In a couple of years ago, we developed a Linux-based real-time kernel, named TMO-Lin...
详细信息
The TMO (time-triggered message-triggered object) model is a well-known real-timeobject model for distributedtimeliness computing. In a couple of years ago, we developed a Linux-based real-time kernel, named TMO-Linux, supporting deadline driven executions of TMO's. TMO-Linux and its distributed IPC subsystem have been used well in developing networked control systems consisting of cooperating embedded devices, but there have difficulties in executing some TMO applications accurately due to the lack of timeliness in distributed communications. To overcome this problem, we newly developed a real-timedistributed IPC over ieee1394 for the TMO-Linux kernel. In the new system, predictable delivery services for real-time messages are provided by isochronous transmissions of ieee1394. To implement predictable delivery services, each node is set to have its own isochronous channel for receiving data that is allocated to a fixed time-slot bandwidth in an ieee1394 frame. This paper presents an implementation technique for the ieee1394-based real-timedistributed IPC and collaborations of computing nodes using TMO-Linux
暂无评论