8858476
A Parallel Algorithm for Graph Matching and Its MasPar Implementation
Search of discrete spaces is important in combinatorial optimization. Such problems arise in artificial intelligence, computer vision, operations research, and other areas. For realistic problems, the search spaces to be processed are usually huge, necessitating long computation times, pruning heuristics, or massively parallel processing. We present an algorithm that reduces the computation time for graph matching by employing both branch-and-bound pruning of the search tree and massively-parallel search of the as-yet-unpruned portions of the space. Most research on parallel search has assumed that a multiple-instruction-stream/multiple-data-stream (MIMD) parallel computer is available. Since massively parallel stream (SIMD) computers are much less expensive than MIMD systems with equal numbers of processors, the question arises as to whether SIMD systems can efficiently handle state-space search problems. We demonstrate that the answer is yes, and in particular, that graph matching has a natural and efficient implementation on SIMD machines.
44457281
An improved algorithm for relational distance graph matching
One of the problems in computer vision is to give a computer a representation of a scene and recognize the objects in the scene and their spatial relationships. This involves low-level vision (image processing), mid-level vision (feature extraction and measurement) and high-level vision (interpretation). One important part of high-level vision is relational matching, the process of matching two relational descriptions of objects, often for the purpose of object identification. This paper presents an improvement of the original method by Shapiro and Haralick for solving the relational distance graph matching problem for unlabeled graphs on a parallel computer.
17318100
Using an architecture description language for quantitative analysis of real-time systems
An architecture description language (ADL) specifies the structure of an overall system as an assembly of interacting components. ADLs can serve as input to a variety of development tools. We outline the Avionics Architecture Description Language, an emerging SAE standard for describing the architectures of hard real-time, safety-critical embedded computer systems. We describe a suite of tools that perform a set of verification, modeling and analysis, and implementation activities given an AADL specification. We summarize a study that applied these technologies using data about a complex avionics system, identifying and discussing some of the issues raised by this exercise.
19591181
RAVE: Real-Time Services for the Web
Abstract RAVE provides Web clients with real-time data services. Thus, RAVE supports live and stored video and audio as well as less typical real-time services such as MIDI and information services (e.g., news or stock market feeds). The system is extensible so that new real-time services can easily be added. RAVE has a flexible distribution architecture: it supports unicast and multicast, as well as both real-time data sources and sinks. RAVE integrates well into the Web so that many multimedia applications may be written using simple HTML extensions. We describe the RAVE architecture, the Web-client facilities that are required to support it, and three applications we have built using RAVE: a video library, a video mail system, and a video-conferencing tool.
10840593
The Web: Interactive and Multimedia Education
The World Wide Web is becoming increasingly important in the provision of education, as recognised by several high profile UK government reports. Improved tools for developing Web-based teaching and learning materials, together with focused training by individuals, institutions and national programmes, have led to a greater confidence in network technologies by educators at many levels. Higher education institutions have been leading players in the UK in the development of innovative ideas for exploiting the educational potential of the Web. This paper presents examples of several techniques in evidence in UK higher education which demonstrate some of the key innovations in teaching and learning, focusing on the themes of multimedia and interactivity. Some of the pedagogic and technology issues associated with these techniques are identified, and the way in which integration into the curriculum can be achieved is explored. This integration takes many aspects of the learning process into account, from the delivery of information and references, through demonstration, example and practice, to learning by reflection and assessment. In particular, the way in which the Web encourages the trend away from directed teaching and towards self-paced and distance learning is investigated. The Web is shown as supporting the learning process in many more ways than its traditional information delivery role. Three main areas explored are: (1) Virtual environments, where real-life scenarios are reconstructed to bridge the gap between theory and practice; (2) interactive simulations, which allow the investigation of changing experimental conditions without the cost and effort of laboratory equipment; and (3) assessment, which can provide valuable feedback to teachers and learners alike, exploiting both interactive and multimedia elements to give added value to online educational materials.
1741470
Architectural Mismatch or Why it's hard to build systems out of existing parts
Many would argue that future breakthroughs in software productivity will depend on our ability to combine existing pieces of software to produce new applications. An important step towards this goal is the development of new techniques to detect and cope with mismatches in the assembled parts. Some problems of composition are due to low-level issues of interoperability, such as mismatches in programming languages or database schemas. However, in this paper we highlight a different, and in many ways more pervasive, class of problem: architectural mismatch. Specifically, we use our experience in building a family of software design environments from existing parts to illustrate a variety of types of mismatch that center around the assumptions a reusable part makes about the structure of the application in which is to appear. Based on this experience we show how an architectural view of the mismatch problem exposes some fundamental, thorny problems for software composition and suggests possible research avenues needed to solve them.
33532247
Running an NSF REU program: observations, comments and suggestions
The Department of Computer Science at the University of Alabama, in conjunction with the National Science Foundation (NSF), offered a Research Experiences for Undergraduates (REU) program during the summer of 1991. This paper discusses the administration, structure, organization, and research efforts associated with this program.