This paper deals with the resource allocation problem (RA-problem) in which the execution time of each job is decided like that job-load does not exceed the capacities of resources. Though there are many methods to solve the RA-problem, PERT/LOAD is the almost only method to solve it in practical processing time. However, the practical result can not be obtained by using PERT/LOAD.
In this paper, the extended PERT/LOAD algorithm with the following features is proposed.
(1) As initial plan, each job is allocated at the optimal execution time.
(2) If job-load exceeds the capacities of resources on the above-mentioned initial plan, three types of job-load balancing means are applied. The first is one that postpones the execution time of job. The second is one that advance the execution time of job. The last is one that gjves up job.
(3) The policies to apply the above-mentioned job-load balancing means are described in the form of IF-THEN rule in order to realize the flexible modification of the policies. The proposed method selects and adopts appropriate job-load balancing means according to the policies.
This algorithm has been applied to a real resource allocation problem in a supermarket. This application demonstrates the practical solution and processing time.

View full abstract

For the efficient operation of power transmission facilities, the authors developed a new fault location method using the current induced in overhead ground wires (GWs) under fault conditions by analysing its distribution pattern along the power line. This method is capable for locating fault sections in complicated secondary systems (66_??_154kV classes).
Since GW current distributions change depending on not only operational conditions but also meteorological conditions, it is quite difficult to estimate them exactly by calculation. Also, the measurement data of GW current contain a certain vagueness. We have already proposed a method to evaluate the features of GW current distribution patterns using fuzzy sets, and succeeded to locate fault sections in actual commercial lines.
In many cases, however, secondary power transmission systems are generally combined with complicated line configurations and power sources. It is thus necessary to introduce various domain-specific knowledge for the fault location of all kinds. The new fault location method uses expert system to cope with this requirement.
This paper describes the vagueness of measured GW current and the necessity of the domain-specific knowledge first, and then, the detailed process of the method as (1) the evaluation of heuristics, (2) expression of knowledge and (3) fuzzy inference. And finally, the applicability of the method is confirmed by the detailed simulation for various fault types using EMTP (Electro Magnetic Transients Program).

View full abstract

The study of human behavior in manual control systems is reevaluated in relation ot fuzzy control. Human behavior in this problem means not only physical action but also thinking processes such as cognition, reasonning, optimization decision and learning. The human performance of this kind is related to the interface. In this paper, we investigate experimentally the effects of interface as to the manual control of double inverted pendulum. This system is suitable to the study of human behavior, because the stability is changed sensitively with the skillness of subjects and also with the quality of interface. Besides the general performance of interface, the effect of prediction is experimented in detail. Then we get some qualitative and quantitative results as for the prediction interval, the gain constants of manipulation and display, and the prediction error. These results are well explained by a hypothesis of human skillfullness suggested in brain physiology, that is, an action-model is formed in cerebellum after practice and then human behavior becomes more acculate and quick because of feedforward action by this model.

View full abstract

With developments in medical electronics and other advanced electronic techniques a new trend in prosthetic techniques for internal organs is arising. It comes not noly from medical electronics but also from the techniques of industrial electronics. Moreover, progress in precision mechanical engineering is rapidly extending the life of apparatus which has to operate continuously for many years, and it is now possible to make artificial internal organs. An area, discussed here, in which the progress of technology has brought achievements is that of artificial heart systems employing the circulatory model with autonomic nerve. The model is controlled only the changes of CO₂ density and mean blood presser. Heart rate, minute volume, mean blood pressure of the artificial heart system employing the circulatory model is evaluated with a mock circulatory system.

View full abstract

A digital multiplier circuit module is proposed, which is cascadable to perform multiplication for any word length, without the use of external circuitry. The number of cascaded modules can be changed dynamically, so that it is useful for designing a system, where many high speed multiplications and less speed but high precision multiplications coexist, as in the application to robot control or image processing.
The soundness of the circuit was confirmed by making one-chip integrated multipliers, and no drawbacks are expected if it is used as macro cells in VLSI.
No other method can compare with the parallel multiplier for speed, but to multiply numbers with digits beyond the chip capability, it is necessary to prepare not only several parallel multipliers but also external circuitly.
Such an experience is what we encounter due to change of specification or application environment. The proposed method is useful to cope with such problems.

View full abstract

Sensitive and quick-response nonlinear inductance characteristics are found for high Tc superconducting (YBa₂Cu₃O_7-x bulk) disk cores with tightly wound coils at 77K in which soft magnetic BH hysteresis loops are observed. The permeability changes from nearly zero (Meissner effect) to the vacuum permeability applying a coil-current magnetic field H or an external magnetic field Hex due to flux penetration effect. Theoretical curves of permeability versus field characteristics and initial magnetization curve are obtained using a flux penetration model.
The magnetizing frequency can be set to more than 20MHz due to the absence of eddy current losses, which is difficult for conventional ferromagnetic cores made of Permalloy, amorphous materials, and ferrite. New quick-response fluxgate magnetic-field sensors are constructed using modulator circuits with AC or DC voltage sources. The former is used for second-harmonic type sensors and DC output type sensors, while the latter is for voltage-output multivibrator bridge type sensors. The sensitivity is about 10^-4A/m for AC fields and the cut-off frequency is about 100kHz for several MHz excitation.

View full abstract