An image sensor is proposed which is driven from back of image sensing area and which detects the channel potential modulated by the stored signal charge. The characteristics of the sensor with 1, 000×1, 000 cell/cm2 were simulated by a numerical analysis which solves simultaneous continuity equations for the potential, the electron and hole currents. In this analysis, a driving method is adopted which suppresses blooming during the charge storage time but allows it only during the very short readout time. The analysis indicated that the charge handling capability reaches 1.53×105 hole/cell and that the conversion factor is 3.7 μV/hole. The proposed sensor promises to have high photo-sensitivity and wide dynamic range.
There exist many types of cooperativity in the mathematical models and computer simulations of neural networks. In a previous paper we presented a reinforcement learning network with a different type of cooperativity from that of neural networks, using self-interested learning automata. In this paper we generalize our previous reinforcement learning algorithm in order to solve some learning problems with variable random environments, and also present a new algorithm based on Bayes decision theory. Simulation results show how cooperative activity in reinforcement learning networks can solve learning control problems.
A micro-ECT (Eddy Current Testing) probe which consists of a planar microloop inductive magnetic sensor array and a pancake-type exciting coil was developed to upgrade the ECT technology on the inspection for a steam generator (SG) tubing in a pressurized nuclear power plant (PWR). Eddy currents and resultant magnetic fields are perturbed due to a flaw in a conductor. The flaw is detected via perturbation of electromotive force (EMF) and phase from the array. Flaws manufactured by electric discharge machining (EDM) in INCONEL 600 1.25mmt planar specimens were detected and reconstructed by using stacked database and simplified algorithm. Even outer 10% flaw could be detected. Measured EMF and phase signals were compared with numerical results obtained by using a three dimensional eddy current and field analysis code and verified. It was confirmed by the experiment that the spatial resolution of detection of the micro-ECT probe is superior to that of the conventional pancake-type ECT probe. Finally we demonstrated that we could establish the same measurement speed using the micro-ECT probe as that using the pancake-type ECT probe.
This paper presents the linearity between the driving current and the vibration displacement of an axial sliding actuator for a high-density optical head. It also investigated the life of such an actuator. The linearity depends upon the clearance and the contact-force between an aluminum sleeve and teflon-coated axis of 2mm diameter and also the sleeve-roughness. These parameters were investigated to obtain the optimal servo conditions. These are a clearance of about 13μm, contact-force of zero, and the least amount of roughness. The actuator life was confirmed under accelerated-life testing in which the actuator was driven at three times the acceleration of the disk specification. Finally, the life was guessed to be 12, 000 hours under normal driving conditions for high-density optical head.
In order to optimize the feeding voltage of substations with diode rectifiers or the voltage-current characteristics of substations with thyristor rectifiers in dc railway power feeding systems, a computer simulation model which can set the following parameters is needed: (1) track profile and location of stations and substations, (2) substation characteristics, (3) train characteristics and (4) train scheduling data, especially start-to-stop time between stations next to each other. Setting parameter (4) is not so easy because acceleration performance of trains depend on the line voltage. In the conventional simulation programs, this causes fluctuation of start-to-stop time of trains which has great influence on energy evaluation. For this reason, the results of existing works on optimization of dc power feeding systems using conventional simulation models did not have enough reliability. For this reason, we developed a new simulation program named RTSS, and implemented the simulation model in which trains run with precisely fixed start-to-stop time. In realizing this, we took advantage of the fact that coasting and braking performance is not affected by fluctuation of the pantograph voltage. Because of this fact, the time to take to reach the next station with only coasting and braking is easily estimated given the present position and velocity. Using this technique, we can easily fix start-to-stop time precisely by altering the point to stop accelerating according to the condition. In this paper, the authors describe in detail the simulation model implemented in RTSS, and discuss about its reliableness to show that the new model is superior to the existing models for evaluation in optimizing power feeding systems.
This paper deals with a problem of determination of feedback gains in order to achieve required performances under linear time invariant perturbations. Based upon Lagrange multiplier method, our proposed method determines feedback gains which ensure both robust stability and robust performance for a linear uncertain system. We apply it to a nonlinear crane system control design. At first we partition the nonlinear system into some uncertain linear systems. Next we apply our proposed method to each uncertain linear systems. We can show its application is easy and consequently nonlinear crane control system can be easily designed. Finally it is shown in a numerical example that our proposed method is effective.
This paper proposes a method which makes full use of the functions of information representation and procedural and declarative knowledge of S-model to derive programs using abstract data-types such as sets and relations and to refine them to programs manipulating arrays and pointers. In this method, program derivation requires 2-phases; first, a syntax-type (a program control structure and related subproblems with it) is generated by analyzing the structure of problem inputoutput specifications and constraints, and by using rules and axioms in S-model's knowledge-base, and then solution program model is derived by the multi-level search based on the syntax-type. Functions of S-model mentioned above are also indispensable for data refinement, as the refinement is essentially redesign of data structures in the concrete level.
This paper reviews a disturbance canceling control based on a disturbance observer from the view point of servo controllers and gives several new points of this control methodology. Especially, the extended H∞ control, previously proposed by authors, is proven to be a special type of such a disturbance canceling controller which has an ability to shape the frequency response of the complementary sensitivity function.