47079351
A language based formalism for domain driven development
The evolution of programming languages (e.g. machine languages, assembly languages and high level languages) has been the driving force for the evolution of software development from the machine-centric to the application-centric. The 4th generation languages (4GLs), languages defined directly by the composition of domain features, serve as the language-based formalism for the emerging Domain Driven Development paradigm. The 4GLs are defined in Two-Level Grammar++ and can be compiled into 3GLs using the 4GL compiler framework.
17507277
Transforming business process models: enabling programming at a higher level
Two practical paradigms are presented, which facilitate domain concepts to be directly used to model business operations: the first paradigm is based on the business artifacts and their life cycle; the second paradigm is based on the business tasks and their sequencing. Transformation is an effective way to bridge the gap between business level analysis and IT solutions. We present algorithms that transform business process models based on these two paradigms into IT solutions of Web service platform. The specific problems we addressed in this transformation are: 1) how to generate the implementation code of an optimal size; 2) how to preserve the natural structure of business process models in the generated code.
6398503
Real-time schedulability of two token ring protocols
When designing real-time communication protocols, the primary objective is to guarantee the deadlines of synchronous messages while sustaining a high aggregate throughput. The authors compare two token ring protocols for their suitability in hard-real-time systems. A priority driven protocol (e.g., IEEE 802.5) allows implementation of a priority based real-time scheduling discipline like the rate monotonic algorithm. A timed token protocol (e.g., FDDI) provides guaranteed bandwidth and bounded access time for synchronous messages. These two protocols are studied by deriving their schedulability criteria, i.e., the conditions which determine whether a given message set can be guaranteed. Using these criteria, the average performance of these protocols is evaluated under different operating conditions. It is observed that neither protocol dominates the other for the entire range of system parameter space. The conclusion is that the priority driven protocol performs better at low bandwidths (1-10 Mb/s) while the timed token protocol has a superior performance at higher bandwidths.<<ETX>>
195350091
Design and implementation of a pluggable fault tolerant CORBA infrastructure
In this paper we present the design and implementation of a Pluggable Fault Tolerant CORBA Infrastructure that provides fault tolerance for CORBA applications by utilizing the pluggable protocols framework that is available for most CORBA ORBS. Our approach does not require modification to the CORBA ORB, and requires only minimal modifications to the application. Moreover; it avoids the difficulty of retrieving and assigning the ORB state, by incorporating the fault tolerance mechanisms into the ORB. The Pluggable Fault Tolerant CORBA Infrastructure achieves performance that is similar to, or better than, that of other Fault Tolerant CORBA systems, while providing strong replica consistency.
17666746
Meeting delay requirements in computer networks with wormhole routing
We study high performance networks with wormhole routing and investigate their performance in terms of meeting message delay constraints. Traditional system uses unregulated greedy transmission control. This may result in unfairness of network access and unbounded packet blocking time, making it very difficult to efficiently support real-time applications. To overcome this problem, we propose a regulated transmission control method in which packet transmission at the source is regulated and hence unnecessary network contention is eliminated The regulated method is a generalization of the unregulated method and can be easily implemented in most of the commercially available networks.
22872614
Performance evaluation of scheduling algorithms for imprecise computer systems
Abstract We study the scheduling of tasks in computer systems which utilize imprecise (partial) computations. In our system, tasks arrive randomly during run-time. Each task has two levels of computation time requirements: the full level computation requirement and the reduced level computation requirement. The reduced level computation of a task takes less time to accomplish than the full level, but produces results which are not as precise as those of full-level computation. We assume that the imprecise results are nonetheless acceptable. The tasks are scheduled in the following way: If the total number of tasks in the system is no more than M —a system parameter—the tasks are executed at the full level. When the total number of tasks exceeds M , the tasks are executed at the reduced level. The system performance under this kind of scheduling and computation model is analyzed. Attention is devoted to development of the explicit formulas for the practically important performance metrics such as the normalized mean task waiting time, the mean task served computation time, and the fraction of tasks fully processed. The effect of variations in parameter values on the system performance is also examined in detail.
15576082
Real-time component-based systems
Component technology has become a central focus of software engineering in research and development. Reusability is a key factor that contributes to its success. The reuse of components can lead to a shortening of software development cycles and savings in software development costs. However, existing component models provide no support for real-time services and some real-time extensions of component models lack of consideration for reusability of components in providing real-time services. In this work, we develop a real-time component-based system that maintains the reusability of components.