Two optimization studies on the design of a three degree of freedom translational parallel platform are conducted and the results are compared. The objective function of the first study maximizes total volume of the manipulator workspace without regard to the quality of the workspace. The second study optimizes the total volume of well conditioned workspace by maximizing a global condition index. The global condition index is a function of the condition number of the Jacobian matrix, providing a means of measuring the amplification error between the actuators and the end effector. Both objective functions involve an integration over the workspace of the manipulator. This integral is approximated using the Monte Carlo method.

A novel 3-DOF parallel manipulator is presented that employs only revolute joints and constrains the manipulator output to translational motion. Closed-form solutions are developed for both the inverse and forward kinematics. The inverse kinematics produces four solutions for each leg of the manipulator. In general, the four solutions are realized in only two unique leg configurations. The forward kinematic solution is reduced to a quadratic equation. So that in general, there are two poses the manipulator can assume for a given set of input joint angles.

Abstract As information systems become more complex, formal methods offer a solution to the increasing problem of ensuring correctness of design and implementation. This paper illustrates the use of mathematical specification to formalise the notion of ‘explanation’. This is relevant to any information system which engages in inference. An information system is regarded as a homogeneous function on states of information. An explanation for a conclusion is regarded as a weakening of the theory relating input to output, such that the same conclusion is reached. As an example, the specification is implemented for a simple statistical classifier to assist medical diagnosis.

Presents a case study of the use of formal specification techniques in the design of a knowledge-based system. The Z specification notation is used in the development of a medical flow chart program, beginning with a highly abstract notion of inference and proceeding by refinement toward a particular implementation for flow charts. Diagnostic inference is modelled by idempotent decreasing functions. The flow chart was found to be significantly more accurate than a statistical classifier (independence Bayes). Formal specification provides several benefits. Design decisions are made explicit and are documented concisely, and the results of making alternative choices can be explored within the same framework. The formal specification also suggests approaches that probably would not otherwise have been considered.>

Presents the initial steps in the design of a rule-based expert system. The purpose of the paper is to show how general, desirable properties of a knowledge-based system can be formalized and explored at an early stage, before details such as those of knowledge representation and uncertainty management cloud the picture. The method used is that of mathematical specification. First an abstract model of inference is presented, then the inference task is decomposed into component procedures. A simple but general theory of dependence between procedures is developed. This enables circularity in a knowledge-base to be avoided and consistency to be maintained. Several more concrete instantiations of the theory are given to illustrate the range of systems that it covers. >