摘要:

Best-match-pair is proposed as a new strategy for the control mechanism of blackboard systems. A generalised blackboard shell with the strategy as the control loop is proposed, which evaluates both solution areas and knowledge sources explicitly. This approach improves the system performance by providing a balanced status feedback between potential knowledge sources and promising solution areas for system control and replanning. It also enhances the system performance by supporting viewpoint reasoning, shadow reasoning, and various metalevel applications, e.g., viewpoint explanation, knowledge acquisition, etc.

DOI:10.1049/ip-e.1991.0001

出版商:IEE    

年代:1991

数据来源: IET

摘要:

A new application of artificial intelligence techniques in automatic compaction design for a VLSI mask layout is presented. To overcome the shortcomings of iterative search through a large problem space within a working memory, and therefore, to speed up the runtime of compaction, a set of rule-based region query operations and knowledge-based techniques for the plane sweep method are presented in this system. Experimental results have explored the possibility of using expert system technology to automate the compaction process by reasoning about the layout design, applying the sophisticated expert rules to its knowledge base.

DOI:10.1049/ip-e.1991.0002

出版商:IEE    

年代:1991

数据来源: IET

摘要:

A novel cell architecture for bit level systolic array multiplication is presented. It is used for the design of a serial-parallel and an iterative pipelined multiplier. The new architecture is a result of combining, in a novel way, the operation of two gated full-adder cell used in conventional multipliers. The new cell circumvents the insertion of zeros in structures with contraflow data streams. As a result, the array is used with 100% efficiency, and the throughput rate is doubled in comparison to most systolic arrays using the contraflowing approach. This is achieved without any increase in hardware, nor the use of a special clock circuitry. Performance analysis of the new multipliers and existing ones has shown the superiority of the new architecture.

DOI:10.1049/ip-e.1991.0003

出版商:IEE    

年代:1991

数据来源: IET

摘要:

The importance of rapid and accurate extraction of ellipses in images for model-based computer vision systems has long been recognised. The Hough transform technique has established itself as a robust method for shape extraction, however, its application to ellipses has been restricted by excessive computational and storage requirements. Direct extension of the Hough technique to ellipses is particularly demanding since a five-dimensional accumulator array is required. This paper presents a novel tristage technique for ellipse extraction based on decomposing the problem into sequentially executed stages. Candidate ellipse centres are determined using an improved centre-finding procedure and novel Hough-based procedures extract the remaining parameters in two further stages. Although multistage parameter extraction is not new, many of the problems that exist in previous schemes are resolved. In the new technique, the dimensionality of the accumulator arrays used does not exceed two, while their ranges are predefined. Memory savings are therefore significant. Concentric ellipses of the same orientation are shown to be extracted with little extra computational demand. Two extensions of the tristage technique to multiple ellipse extraction are presented and compared. When applied to real images, the new technique extracted multiple, concentric ellipses reliably and with reduced complexity.

DOI:10.1049/ip-e.1991.0004

出版商:IEE    

年代:1991

数据来源: IET

摘要:

Gate-level test pattern generation (TPG) techniques are inadequate when considering the complexity and variety of today's circuits. Hence, more abstract approaches must be developed so that TPG efficiency can be increased and inherent bottleneck between test planning and TPG reduced. As an expert system attempts to model human reasoning [1], functional TPG approaches must be used within such an environment as opposed to algorithmic gate-level methods which are beyond the capability of human understanding, memory and reasoning, whereas functional approaches map directly to the human thought process; unfortunately these methods have not been fully developed. The paper discusses how such a test generation approach can be used within an expert system, furthermore a number of heuristics are described to show how TPG can be simplified within such an environment.

DOI:10.1049/ip-e.1991.0005

出版商:IEE    

年代:1991

数据来源: IET

摘要:

The performance of single-buffered banyan networks under certain nonuniform traffic patterns had been studied by Garg and Huang. However, the models used are over simplified and the results obtained may deviate from exact values significantly. Alternative models to achieve more accurate performance estimates are presented. In our models, the destinations of blocked packets residing in the buffers of nodes at stage 1 (and perhaps stage 2, depending on the traffic matrix) are memorised. Compared with those adopted by Garg and Huang, our models are only slightly more complicated. By viewing banyan networks as queueing systems, we apply Little's formula to compute the average packet delays.

DOI:10.1049/ip-e.1991.0006

出版商:IEE    

年代:1991

数据来源: IET

摘要:

The minimisation of Boolean functions is a classical problem. This paper deals with the set of functions which satisfy the equationf(X) =h(g(X1,X2where the variable setXis given by the disjoint union of any setsX1andX2We present an efficient method in the Boolean domain which is based on the theory of Boolean differential calculus and the spectral development using the Walsh transform.

DOI:10.1049/ip-e.1991.0007

出版商:IEE    

年代:1991

数据来源: IET

摘要:

The new iterative construction approach presented in this paper consists of three algorithms, namely, channel expansion routing, track assignment, and module location refinement. These algorithms, contrary to the conventional methods implemented with a sequence of tools separately, are linked with a common data structure which guarantees a maximal compatibility. With an initial nonoverlapping placement as input, the iterative construction approach generates a final layout with more compacted area than the layout result from the one-dimensional compactor or some of two-dimensional compactors. Several layout examples in the literature are tested to show the effectiveness of our approach.

DOI:10.1049/ip-e.1991.0008

出版商:IEE    

年代:1991

数据来源: IET