In this paper, a mathematical model for identifying the static large-spatial pattern of air pollution concentration is developed. Firstly, the source-receptor matrix, which representsa linear relationship between the air pollution sources and the pollutant densities at the monitoring stations (receptors), is identified by a regression analysis. This rough model is used as a first-order approximation. Then, the difference between the output of this rough model and the real system is identified by GMDH (Group Method of Data Handling), that is, the completely unknown nonlinear part of the system is identified by GMDH. The combined approach of source-receptor matrix and GMDH can reduce the average relative error of predicting the concentration pattern by half compared with the use of the rough model of source-receptor matrix alone.

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As an infrared radiation standard for the calibration of radiation thermometers, blackbody radiation was realized by utilizing the phase-equilibrium between solidus and liquidus of antimony. For this purpose, two kinds of blackbodies, a precision-type blackbody radiator for a fundamental standard and a blackbody cell for a simple practical standard, were prepared as a trial and experimented. The both blackbodies were made of high purity graphite and antimony with a purity of higher than 99.999% was sealed in it.
In this paper, the detailed structures of the blackbody radiators are described and the practical method for realizing blackbody radiation at the phase-equilibrium of antimony is reported. In addittion, their reproducibility and the various factors which are presumably responsible for the systematic errors, such as the effectiv emissivity of cavities, the inner wall temperature gradient of them, the stray radiation effect in the measuring system, etc. have been investigated and evaluated.
As a result, it has been concluded that as to the over-all accuracies, the precision-type blackbody as a fundamental standard can be expected to provide higher accuracies than 0.1K and even the blackbody cell as a practical standard can provide enough accuracies of about ±0.2K for industrial use.

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The authors have systematically investigated the effects of vent and sharp splitter on the reattached jet in a wall-reattachment fluidic device.
As reported in this paper, including the results for the cusped splitter and the pentagonal one, the effects of vent and splitter on the reattached jet behaviour, its switching, and the recovery pressure were experimentally investigated.
According to these results, the geometrical configuration of the device was discussed from the viewpoint of designing the wall-reattachment fluidic device.
The results can be summarized as follows:
(1) The cusped and the pentagonal splitters do not suppress the bubble expansion of reattached jet unlike the sharp splitter.
(2) The switching modes can be classified into the splitter switching and the contacting-both-walls one except for the cusped splitter. The splitter switching for the device with vents can be practically treated as the terminated-wall switching.
(3) The optimal configuration of the vent and splitter to give a maximum recovery pressure is made clear.
(4) It is clearly shown that the straightforward design was possible, when the recovery pressure was accepted as one of the performance indexes of the device.

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It is necessary to know the stress-strain characteristics of the material in order to analyze the plastic working of a pressure sensing element. Most of the nominal characteristics are so simple that they are applied to the analysis of the pressure sensing element. In this paper the results of the experiments concerning σ-ε characteristics of 316 stainless steel which is most widely used for pressure sensing elements are reported.
Approximate characteristics were estimated before the experiments were conducted. Three kinds of experiments based on this estimation were carried out. They were the high speed tehsile test, the confirmation of Bauschinger effect and the sharing stress test. The standardized σ-ε characteristics of 316 stainless steel based on the results of these experiments are shown in Fig. 7.
The most important thing is that the operating σ-ε must be on the reversible line for the full range of the input, when the material is used to build the pressure sensing element. The reason for this is explained by taking Bourdon tube as an example.

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Systems whose control inputs are restricted to discrete values are called quantized control systems. Discrete control is usually found in various fields, for example, in socio-economical systems, in ecological systems and in the control problems by digital computers.
Even if a given system is controllable by continuous level controls (an arbitrary small input value is available) it can not be expected that the system is controllable by quantized control inputs. “To what extent can we control the system?” is a fundamental quetion in quantized control systems.
In this paper, the system structure and reachability of quantized control systems are studied. The systems under discussion here are linear, constant and discrete-time dynamical systems over the field of real numbers whose control inputs are restricted to the integer vectors:x(k+1)=Ax(k)+Bu(k)where x(k)∈Rⁿ, u(k)∈Z^m and A and B are real matrices.
Since the cardinality of the set of reachable states is at most countably infinite, the best situation for reachability of the system is that the set of reachable states is dense in the state space Rⁿ, in which case the system is called to be “almost reachable.”
The main results are as follows.
(1) The state space is a direct sum of two subspaces: the “almost reachable subspace” in which the reachable states are dense and the “discretely reachable subspace” in which the reachable states are isolated points. The almost reachable subspace is A-invariant.
(2) The “almost reachability”of a system is closely related to the integral properties of the eigenvalues of A.
(3) When A and B are matrices over the field of rational numbers, the “almost reachability” is dominated only by the eigenvalues.
(4) In the general case when A and B are real matrices, the “almost reachability” is influenced also by the input matrix B. However, the almost reachability can be examined through finite procedure.

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To design shipboard scales, the authors derived the general equation of motion for the simple lever suspended on a moving base, and characterized the behavior of the lever theoretically in previous paper.
In this paper, authors report the experiments to test the theoretical results.
In their experiment, it is planned that the levers have the products of inertia I_yz, I_zx and I_xy and that the angle between the rotation axis of the base and the fulcrum axis may be changed.
As for the motion of the base, the authors constructed a seesaw which has an arm 2.5m long, a maximum swing angle of 0.28rad and a natural period of about 13sec in the laboratory.
The experimental results agree well with the theoretical ones.

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The one-phase flow and the two-phase flow in a fluidic element are investigated by measuring Reynolds stress distributions of the main jets using the laser Doppler velocimeter. In the one-phase flow, a water flow jets from a main nozzle into water and in the two-phase flow, a water flow jets into air.
Some results with the one-phase flow are as follows. When either of the two control ports is closed without an impedance at the output ports, the jet is influenced with a low pressure vortex in the jet attaching side, so that the shear stress and the longitudinal normal stress in the jet attaching side become larger than those in the jet unattaching side. Then, also the jet engulfs the water flow from the control port and the output port in the jet unattaching side, so that the transverse normal stress in the jet unattaching side becomes larger than that in the jet attaching side. When the control port in the jet attaching side is opened, the jet is not influenced with a low pressure vortex. As a result, Reynolds stresses show symmetrical distributions. When either of two control ports is closed and the impedance of the output port in the jet attaching side increases, Reynolds stresses increase. Then transverse normal stress of those, in the jet unattaching side, increases most. These phenomena are caused with the increase of the spill flow.
Some results with the two-phase flow are as follows. When either of the two control ports is closed without an impedance at the two output ports, Reynolds stresses of the two-phase flow are smaller than those of the one-phase flow and are very small especially near the air boundary. This is because the mometum exchange between the water jet and the ambient air is smaller than that between the water jet and the ambient water, so that the water jet diffuses little to the transverse direction in a two-phase flow. With the increase of impedance at the output port in the jet attaching side, Reynolds stresses increase little, for the air arround the jet prevent it to engulf a spill water flow.

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This paper deals with methods of reconstructing, in the stochastic sense, the state of continuous-time dynamical systems with unknown initial conditions and subjected to random inputs. By extending to the stochastic systems the concept of n-observability with a deterministic system, the unknown stochastic states are reconstructed from the statistical knowledge of the system output during a finite time interval provided that the observation system is a scalar.
The technique of the determination of minimal, optimal observation time points is described by paying particular attention to the n-observability in the stochastic sense and the relation between sample and population qualities such as mean and covariance.
Two cases for the state reconstruction are treated such that the confidence intervals of the states are constructed (1) by using only the variances of the outputs at oprimal observation time points and (2) by using the variances and correlation function of the outputs.
In order to clarify the proposed technique for the state reconstruction a numerical example is given and the relations between the confidence intervals and the observation methods are discussed in detail.

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Previously, one of the authors proposed a mathematical model for a sonic oscillator and showed that many features of phenomena occurring in the oscillator could be theoretically explained by this model. However, the effects of the output loading were not studied, since the model was for an oscillator using a load insensitive bistable amplifier.
In this study, the authors experimentally examine how the output loading affects the input characteristics of the bistable amplifier with a relatively small splitter distance and derive an approximate expression for the input characteristics of the load sensitive amplifier. On the basis of the expression, a mathematical model for an oscillator using the load sensitive amplifier is derived and the effects of the output loading are analysed theoretically. The results agree well qualitatively with experimental results.

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The problem of finding unknown parameters in distributed parameter systems from the observations can be formulated as the equations of the first kind, whose solutions are not continuously dependent on the data. These problems are called non well-posed. The regularization or Tihonov's regularization is known as one of the stabilizing algorithms to solve non well-posed problems. In this paper we consider the regularization method for identification of distributed systems. Several approximation theorems are given for finding the solutions of equations of the first kind. Then, the identification problems are reduced to the minimization of a kind of quadratic functionals by using these theorems. On the other hand, it is known that the statistical methods for identification such as the method of maximum likelihood lead to minimization problems of certain specified quadratic functionals. Comparing these quadratic functionals, the relations between the regularization and the statistical methods are discussed.

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In this paper we give a necessary and sufficient condition for causality of general systems. The causality treated here is of a non-anticipation type, that is, the present output does not depend on a future input. Suppose X and Y are an input set and an output set, respectively. Elements of these sets are time functions. Suppose a general dynamical system S is represented by a relation between X and Y such that S⊂X×Y. Let ρ₀: C×X→Y be an initial state response of S where C is a set of states. Then the causality considered here is formulated by the following relation;(∀c)(∀t)(∀x, x')(x^t=x'^t→ρ₀(c, x)|T^t=ρ₀(c, x')|T^t)A system is called causal when it has a casual initial state response. In general not every system is causal and hence causal systems form a special class of set theoretic relations. Since causality is of great significance in systems theory, it is important to identify the class of causal systems. In this paper the following is presented as a necessary and sufficient condition of causality.
(∀(x, y)εS)(∀xεD(S))(∃y)(x^t=x^t→y^t=y^t)We apply this result to several types of general systems, for instance, past determined systems, to examine their causality and, in paticular, derive a necessary and sufficient condition for a linear system to have a causal linear initial state response.

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A quadruped walking has been studied in the field of biological science and engineering mainly, since it is one of the most popular locomotion method of animals, and also has the functional adaptability for rough terrain. But when the quadruped studies are compared with the biped ones, it may be found that the experiment is more difficult with a quadruped because animals are hard to treat and their forms and sizes are different. In view of this, we attempt to introduce the computer simulation method in the quadruped studies.
The proposed mathematical model of quadruped is the first one in our plan. The model is able to correct the given motions of legs in order to maintain the static stability and to calculate the posture and position of the quadruped against a terrain. In illustrations of the application of this system, the crawl gaits of elephant and dog were simulated and kinematically analyzed by widely altering of parameters. Consequently, the following characteristics of quadruped walking became clear; 1) the displacement of the scapula and pelvis with walking effectively reduces the sway of the body, 2) the inclined posture of animals at slope is effective to hold on their walking rhythm as well as to increase the static stability, 3) there is a close relationship between the position of the centre of gravity and the walking cycle, by which animals can move naturally to a dynamic stability from a resting posture.
We desire that these simulation studies will be a new means with respect to the analysis of walking systems, and that those results will be applied to the design of a prosthesis or a legged vehicle.

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This paper describes an experimental system for generating contour lines automatically from stereopaired photographs. The system consists of a pair of projectors, a 32×32 integrated photodiode array mounted on an XY-recorder and a small computer PDP-12 with 8K-word core memory. Contour lines are generated directly from a pair of optically projected images, not by evaluating elevations over the entire field.
The XY-recorder is placed vertically on the floor and on its recording plane a pair of stereo images is projected alternatively from the left and right projectors. The image pair reconstructs a virtual relief, and contour lines associated with an elevation value are obtained by cutting the relief by recording plane. The photodiode array is mounted just on the pen position to detect a pair of image segments; one is a 3.2×3.2mm² area of the left projector image and the other is that of the right projector image. The computer compares the segments and controls the movement of the detector. At each step of the generation process the detector is moved to such a position that the pair images become most alike. The trajectory of the detector movement is recorded by the pen; generating a contour line.

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The ion engine is suitable for a primary or auxiliary propulsion of the long mission time spacecraft because of its high specific impulse. An optimum system design and an engine operation optimization are described in case of an ion engine application for north-south stationkeeping of a synchronous communication statellite.
The optimum design analysis which allows determination of the necessary ion engine operating conditions to yield the lightest possible system to perform N-S stationkeeping is presented. The engine characteristics are modeled and identified by the experimental data, then the daily thrust period about nodal points and the engine net-accelerating voltage are optimized for the lightest system design.
Moreover an on-line computer steady-state optimization technique to keep optimum operating conditions under system component characteristic changes in the environment is presented. The evolutionary optimization (EVOP) approach that uses an iterative procedure with statistical significances which adjust the control variables in successive moves to arrive at the optimum of the objective function is used as an optimization procedure. The net-accelerating voltage and the vaporizer temperature or the propellant mass flow rate are used as the control variables. In this case the controlled object is a 5cm diameter mercury electron-bombardment ion engine. The strategy convergence time was about a few hours. This means that it is possible to optimize engine operating conditions during daily thrust period by this optimization procedure.

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This paper deals with vibrotactile stimulations that are suitable for a reading aid for the blind.
Based on the results obtained from the experiment of recognition time difference and two-point threshold, a vibrotactile stimulator for a blind was proposed. The vibration pattern was produced by a 4×4 array of small vibrator reeds with 200Hz and the entire array fit on a single finger. The new vibrator's power consumption is shown to be lower than one fifth of that of a conventional vibrator.
After a 30k40 minute training time, the rate of correct response was 100% in the articulation test for the characters/_??_/, /_??_/, /_??_/, /_??_/and 70% for the numbers /1/, /2/, /4/, /7/

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This paper presents a heuristic self-organization method for constructing a nonlinear prediction model of complex environmental systems such as a forecast model of river flow.
This prediction algorithm is an improved version of GMDH proposed by A.G. Ivakhnenko, which provides an optimally complex nonlinear structure of input-output relation. Our pro-posed algorithm, “Sequential GMDH” is useful for the prediction of complex nonlinear systems with a large number of variables and with a limited amount of available input-output data.
Efficiency and usefulness of the proposed sequential prediction algorithm are shown with the use of a simulation model. Then this is applied to the flow prediction of the Karasu River, the upper reach of the Tone River. Numerical comparisons are performed between the forecasting model by “Sequential GMDH” and those by the elaborate hydrologic methods and we show that there are improvements in the newly introduced prediction algorithm.

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The purpose of this paper is to investigate the phenomena of the pressure wave propagation in branched, volume-terminated, pneumatic transmission lines. Analytical and experimental results in the time domain are presented to show the interaction between load capacitances (volumes).
The one-dimensional, linear, distributed-parameter transmission line theory for uniform lines by Schuder and Binder is extended to branched pneumatic transmision lines, and the pressure step response of branched lines and the pole-zero configuration of transfer functions are shown. By using the pole-zero configuration, the function of load capacitances on the branched line system and the mechanism of the interaction between load capacitances can be explained readily.
The experimental results for negative pressure steps are compared with the analytical results. Agreement between experiment and numerical solutions based on the simplified analytical model is relatively good.

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The coil weighing flowmeter, here reported, is composed of a vertical circular cylindrical tube, an iron float in the tube, a coil surrounding the tube and a balance for weighing the coil. The coil with electric current exerts a magnetic force upon the float.
The measuring principle is as follows: The fluid to be measured flows steadily upwards through the tube, and the float is kept at rest in the flowing fluid. The condition of equilibrium for the float is that the sum of the forces exerted on it is equal to zero. The forces are the gravity, the buoyancy, the drag force which is proportional to the square of the relative velocity of fluid and float, and the magnetic force exerted by the coil. The float exerts a reaction magnetic force upon the coil to reduce apparently the mass of the coil. Therefore, the magnetic force is known by weighing the coil. As the relative velocity is proportional to the flow rate, the decrease of apparent mass of the coil varies proportionally to the square of flow rate.
The results of experiments show that the flow rate can be measured by the calibrated coil weighing flowmeter.

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In this paper, the problems of the output reachability and a kind of input-output equivalence for a class of nonlinear systems are considered by applying the theory of differential geometry. Because the right hand side of the dynamical equation describing a motion defines a vector field on some manifold, the input-output equivalence can be interpreted in terms of the vector field of the system. The input-output equivalence or the equivalence of the sets of vector fields is defined as follows; if two systems, defined on the same manfold, have the same output equations and the equivalent sets of vector fields, then they produce the same output for the same input. This type of equivalence concept was introduced by Brockett for studying the minimal realization problem of bilinear systems. The systems considered here are defined on a real analytic manifold. The state equations depend on the input variables linearly. Their output equations are analytic with respect to state varables. These systems are the same type studied by Sussman and Jurdgevic, and they are a generalization of bilinear systems. The main results obtained here are the necessary and sufficient conditions for the output reachability and the equivalence of the sets of vector fields. These conditions are algebraic and easily computable. Through these discussions, the concept of the invariant Lie algebra is derined, which corresponds to the invariant subspace of linear systems.

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