Analysis of minimization algorithms for multiple-valued programmable logic arrays

This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. As such, it is in the public domain, and under the provisions of Title 17, United States Code, Section 105, may not be copyrighted.Proceedings of the 18th International Symposium on Multiple-Valued Logic, May 1988, pp. 226-236We compare the performance of three heuristic algorithms [3,6,13] for the minimization of sum-of-products expressions realized by the newly developed multiplevalued programmable logic arrays [9]. Heuristic methods are important because exact minimization is extremely time consuming. We compare the heuristics to the exact solution, showing that heuristic methods are reasonably close to minimal. We use as a basis of comparison the average number of product terms over a set of randomly generated functions. All three heuristics produce nearly the same average number of product terms. Although the averages are close, there is surprisingly little overlap among the set of functions where the best realization is achieved. Thus, there is a benefit to applying different heuristics and then choosing the best realization

Scoping analytical usability evaluation methods: A case study

Analytical usability evaluation methods (UEMs) can complement empirical evaluation of systems: for example, they can often be used earlier in design and can provide accounts of why users might experience difficulties, as well as what those difficulties are. However, their properties and value are only partially understood. One way to improve our understanding is by detailed comparisons using a single interface or system as a target for evaluation, but we need to look deeper than simple problem counts: we need to consider what kinds of accounts each UEM offers, and why. Here, we report on a detailed comparison of eight analytical UEMs. These eight methods were applied to it robotic arm interface, and the findings were systematically compared against video data of the arm ill use. The usability issues that were identified could be grouped into five categories: system design, user misconceptions, conceptual fit between user and system, physical issues, and contextual ones. Other possible categories such as User experience did not emerge in this particular study. With the exception of Heuristic Evaluation, which supported a range of insights, each analytical method was found to focus attention on just one or two categories of issues. Two of the three "home-grown" methods (Evaluating Multimodal Usability and Concept-based Analysis of Surface and Structural Misfits) were found to occupy particular niches in the space, whereas the third (Programmable User Modeling) did not. This approach has identified commonalities and contrasts between methods and provided accounts of why a particular method yielded the insights it did. Rather than considering measures such as problem count or thoroughness, this approach has yielded insights into the scope of each method

RDF, the semantic web, Jordan, Jordan and Jordan

This collection is addressed to archivists and library professionals, and so has a slight focus on implications implications for them. This chapter is nonetheless intended to be a more-or-less generic introduction to the Semantic Web and RDF, which isn't specific to that domain

Graphical Support for the Design and Evaluation of Configurable Logic Blocks

Developing a tool supporting humans to design and evaluate CLB-based circuits requires a lot of know-how and research from different fields of computer science. In this work, the newly developed application q2d, especially its design and implementation will be introduced as a possible tool for approaching CLB circuit development with graphical UI support. Design decisions and implementation will be discussed and a workflow example will be given.:1 Introduction 1.1 Forethoughts 1.2 Theoretical Background 1.2.1 Definitions 1.2.2 Expressing Connections between Circuit Elements 1.2.3 Global Context and Target Function 1.2.4 Problem formulation as QBF and SAT 2 Description of the Implemented Tool 2.1 Design Decisions 2.1.1 Choice of Language, Libraries and Frameworks 2.1.2 Solving the QBF Problem 2.1.3 Design of the Internally Used Meta-Model 2.1.4 User Interface Ergonomics 2.1.5 Aspects of Schematic Visualization 2.1.6 Limitations 2.2 Implemented Features 2.2.1 Basic Interaction 2.2.2 User-Defined Components 2.2.3 Generation of Circuit Symbols 2.2.4 Methods for Specifying Functional Behaviour 3 Implementation Details 3.1 Classes Involved in the Component Meta-Model 3.2 The Document Entry Class and its Factory 3.3 Model and View 3.3.1 The Model Element Hierarchy 3.3.2 The Schematics Element Hierarchy 3.4 The Quantor Interface 4 An Example Workflow 4.1 The Task 4.2 A Component Descriptor for Xilinx’ LUT6-2 4.3 Designing the Model 4.4 Computing the Desired Configuration 5 Summary and Outlook 5.1 Achieved Results 5.2 Suggested Improvements References A Acronyms and Glossary B UML Diagram

Division-based versus general decomposition-based multiple-level logic synthesis

During the last decade, many different approaches have been proposed to solve the multiple-level synthesis problem with different minimum functionally complete systems of primitive logic blocks. The most popular of them is the division-based approach. However, modem microelectronic technology provides a large variety of building blocks which considerably differ from those typically considered. The traditional methods are therefore not suitable for synthesis with many modem building blocks. Furthermore, they often fail to find global optima for complex designs and leave unconsidered some important design aspects. Some of their weaknesses can be eliminated without leaving the paradigm they are based on, other ones are more fundamental. A paradigm which enables efficient exploitation of the opportunities created by the microelectronic technology is the general decomposition paradigm. The aim of this paper is to analyze and compare the general decomposition approach and the division-based approach. The most important advantages of the general decomposition approach are its generality (any network of any building blocks can be considered) and totality (all important design aspects can be considered) as well as handling the incompletely specified functions in a natural way. In many cases, the general decomposition approach gives much better results than the traditional approaches

RDF, the semantic web, Jordan, Jordan and Jordan

This collection is addressed to archivists and library professionals, and so has a slight focus on implications implications for them. This chapter is nonetheless intended to be a more-or-less generic introduction to the Semantic Web and RDF, which isn't specific to that domain

An Ada-like language to facilitate reliable coding of low cost embedded systems

Due to a lack of operating system (0/S) support, it is more difficult to develop programs for embedded systems than for workstations. For those developing on a low budget, the problem is often further compounded by the necessity of using inappropriate, 0/S dependent, compilers. This study attempts to ascertain those elements of a High Level Language (HLL) which are absolutely necessary and implementable to produce reliable, efficient, embedded programs without the benefit of a large budget. The study is based upon the Ada philosophy as the Ada language incorporates many desirable features for modelling real-world problems in terms of embedded solutions. By implication, the research provides a small step towards an increased availability of low cost tools to assist in the development of reliable and efficient code for use in medium performance embedded systems

High integrity hardware-software codesign

Programmable logic devices (PLDs) are increasing in complexity and speed, and are being used as important components in safety-critical systems. Methods for developing high-integrity software for these systems are well-known, but this is not true for programmable logic. We propose a process for developing a system incorporating software and PLDs, suitable for safety critical systems of the highest levels of integrity. This process incorporates the use of Synchronous Receptive Process Theory as a semantic basis for specifying and proving properties of programs executing on PLDs, and extends the use of SPARK Ada from a programming language for safety-critical systems software to cover the interface between software and programmable logic. We have validated this approach through the specification and development of a substantial safety-critical system incorporating both software and programmable logic components, and the development of tools to support this work. This enables us to claim that the methods demonstrated are not only feasible but also scale up to realistic system sizes, allowing development of such safety-critical software-hardware systems to the levels required by current system safety standards