The authors have been engaged in the development of a wide frequency range wattmeter utilizing a Digital Signal Processor ; with input terminals being made up of voltage/current sensors of magnetic balance type. In general, measurements errors are attributed to the measuring interval “T”, the measured voltage and/or current frequency. However, this error can be reduced to minimum by setting T to integer multiples of the AC voltage period. They propose, in this paper, a procedure and a DSP control program to reduce measurement error. Experimental results are given to illustrate the efficiency of this error reduction system.
In this paper we deal with assessing the environmental impact of heavy road traffic. For this purpose, the multiattribute disutility functions for the air pollution, noise and dust are tried to construct based on the information obtained from the questionnaires to the specialists of environmental problems. When we asked the environmental specialists to answer the questionnaires, we asked them to act as the regional inhabitants of the concerning road. The interdependence, called convex dependence, among multiple attributes is taken into account when a disutility function is constructed. Furthermore, analyzing the answers to the questionnaire based on a cluster analysis, the environmental specialists were classified into two groups, and an average disutility function for each group was obtained. Since the disutility function obtained in such a way is clearly a monotone decreasing function of the distance from the road, we call the disutility function as a “conscious distance from the road”. Using this conscious distance from the road it is possible to measure the effectiveness of various counter-measures for preventing the environmental impact of heavy road traffic.
This paper describes a verbal representation for shape recognition of multi-dimensional functions. It is expected that the verbalizing of the shape will make it possible to represent shape features, an intelligent shape representation, which can not be represented in multi-dimensional space by contour lines. That is because the verbalizing is one of symbolizing methods of the shape, by which an intelligent processing is executed on a computer. First, the words used for a topographical representation in the geography are discussed. Second, the words used for the verbal representation, TOP, BOT (Bottom), SAD (Saddle), RID (Ridge), VAL (Valley) and SLO (Slope), are defined in n-dimensional space. The truth value of the words is also evaluated based on fuzzy set theory. Finally, shape representations of two-dimensional and three-dimensional functions are shown and compared with those by contour lines.
This paper presents a local approach for real-time collision avoidance among autonomous mobile robots based on non-linear programming. Here, we consider multiple mobile robots travelling to their own destinations in a two-dimensional workspace, e. g., automated guided vehicles in a factory shop. Each robot is assumed to have its identical area and limited sensing area represented by closed circles. In this approach, a distance function between neighbouring two robots is introduced to set up the velocity vector constraint for robots. The desired velocity vector, which enables a robot to navigate without collision by following it, is given as the optimal solution of the objective function under this velocity vector constraint. Our method is implemented using the computer simulated robots. The feasibility and effectiveness of our method are also discussed through the simulation results.