This paper is concerned with the deterministic state estimation problem for a linear time-invariant system with delay
x(t)=Ax(t)+Dx(t-h)+Bu(t), h>0
y(t)=Cx(t).
The object is to find a sufficient condition for the constructibility of an observer which yields an estimate that approaches x(t) as t→∞.
The result is as follows. If (i) (C, A) is an observable pair, and (ii) when (C, A) is written in a Luenberger's canonical form, D=D₁+D₂ where D₁ is a matrix having rows written as linear combinations of the rows of C, and D₂ is an upper triangular matrix, then an observer is constructible under an arbitrary specification of the degree of the decay of the estimation error.

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In this paper, a systematic method of constructing local state feedback for composite control systems is proposed. The composite control systems investigated here are not only composite in the sense that some subsystems are interconnected, but also have a local control input at each subsystem.
This local feedback is a suboptimal control for the composite control systems and the same control is optimal for the disconnected systems. By using this suboptimal control, a sufficient condition for the uniformly asymptotic stability is obtained.
When this condition is satisfied, the suboptimal cost is bounded above by the optimal cost of disconnected systems. Assuming some conditions, a more versatile stability condition is introduced.

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Causality is one of the most fundamental properties of dynamical systems. Clarification of its nature is an important subject in the systems theory.
In our previous paper we characterized the causality for a rather restricted class of time systems.
In this paper we present a new condition for causality; that is,
(∀x, x')(∀t)(x^t=x'^t→S(x)|T^t=S(x')|T^t).
We show that this condition is a necessary and sufficient condition for the time systems with output completeness to be causal. The output completeness is introduced here as one of the basic properties of time systems. It is shown that the class of time systems with output completeness is sufficiently large, including finite automata, the systems described by linear ordinary differential equations and also the systems treated in our previous paper.
In this sense this paper extends our previous results and establishes a practically complete characterization of causality for general time systems.

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It is commonly belived that a bilateral negotiation between two countries can reveal its whole content only after publication of the documents explained by the responsible officials, for it is difficult to procure data on a countory's internal motivation affecting the decision in the negotiation. Not denying this fact, however, we have attempted to show that a certain type of negotiation can be modeled on the basis of publicly available data. To get insight into the pattern of conflicts in this new era of oceanic territories, we have chosen the fishery negotiation between Japan and the Soviet Union. We have made the state space equation model in modern control theory based on the negotiation data 1957∼1976, and we have forecasted the result of negotiation 1977. The results shows that the model's predictive performance is remarkably good. We have identified the five majore structual components of the negotiation which characterize as the politics of decrementalism.

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In this paper, a new algorithm of a searching method is described. Previously we suggested a new searching method called the SCAM (Sequential Coordinate Addition Method) and it gave us good results.
In the SCAM, one coordinate is added in a searching trial. By this reason this method was no better than other conjugate direction method before the addition of all coordinates. Here, we propose a steep descent SCAM. In this paper, we describe an algorithm of this new method and compare its convergence with that of an other method.

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The application of singular perturbation theory to a fixed-end-point problem is shown in this paper. We deduce some sufficient conditions for the existence of the suboptimal solutions and give a systematic method for obtaining these asymptotic series solutions which are valid uniformly on the whole interval by using boundary layer methods. These conditions derived here are compared with those given by other authors. The design procedure given in this paper is applied to the fixed-end-point problem of a nuclear reactor system in order to demonstrate its effectiveness.

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In this paper the sampled-data output feedback linear regulator problem is considered. The sensitivities, with respect to the sampling period, for the sampled-data control systems are computed about the zero sampling period in two cases. In the first case the system is a sampled-data control system using the optimal output feedback gains of the continuous system. The Lyapunov-type matrix equations for the first and second-order sensitivities of the cost matrix are obtained. In the second case the system is an optimal sampled-data output feedback control system. The linear simultaneous matrix equations for the first and second-order sensitivities of the cost matrix and the output feedback gain matrix are derived.
Furthermore, from these results it is concluded that, for the output feedback regulator, the continuous control system does not necessarily give the best cost performance.

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A pattern may be thought of being composed of fictious particles which exert attractive or repulsive forces at one another as charged particles do. Imagine two such particles. Let us assume that within a certain distance, they exert at each other an attractive force as a function of the distance and that at a distance farther they exert at each other a repulsive force. The force exerted on a particle is obtained by summing the forces from other particles. Then the displacement of the particle is determined proportionally to the force. The pattern is deformed as the particles move. The process is simulated in a digital computer and is repeated until the pattern becomes stationary being composed of several separate points, such as the end points, the cross points the bending points and so on. The stationary patterns for most of the OCR-B font alphanumerics are different from each other. This makes their discrimination quite easy.

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The use of remotely sensed multispectral data to construct a land use map was studied. The results of automatic supervised classification by the most likelihood ratio (MLH), the linear discriminant function (LDF), the minimum Euclide an distance (MED) and by the correlation coefficient methods (CCM and NCM) were compared. The data were obtained by an airborne multispectral scanner JSCAN-AT-12 M. For the comparison four channel data (blue, green, red, and near IR) were used. The training fields were selected for eight categories (pond, forest, field, marsh, bare soil, road, railway and concrete). If the distribution of the data were Gaussian, the correct classification rate (CCR) decreases as we change the methods of classification from one to another in the above mentioned order. This was the case for the training field data, but not so for those of the test fields. This means that an essential problem in practice is the generality of the training field data. The skewness and kurtosis calculated from the data of each channel for the training area show that the distribution are not Gaussian. This, however, does not have a serious effect on the classification in this case.
For the test data the best result (about 80% CCR) was obtained by MED, and the worst (about 60%) by MLH. In MLH, if the data had small variances slight differences were exaggerated because the data lacked generality. On the other hand, if the data had large variances, the differences between categories were likely underestimated.

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In this paper, we consider the manual control of a yo-yo which present us one of our familiar manipulation problems. We can easily control a yo-yo with visual and bodily sensitive feedback. It is a complex problem to replace the human operator with a controller, because we do not know the internal structure of the human operator. Since a human operator is included in a man-machine system, a meaningful performance index is sometimes very difficult to define.
Topics in this paper are summarized as follows: 1) We analyze the dynamical equations of a yo-yo theoretically and examine the various dynamical characteristics by the energy integral. 2) We present some input patterns as the experimental data which are up-and-down motions of an arm. 3) We formulate the optimal control problem and solve it utilizing the mathematical programming. Computational examples for a human operator are illustrated and the practical performance index is discussed as compared with the experimental results.

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To estimate the accuracy of the optical thermometry, data for emissivities are indispensable. Recently the reliability of the optical thermometry instruments has increased, as seen in the steel making processes. In these processes the near-infrared wavelength is commonly used for detection of the temperature of a radiating surface. But there are little studies about the emissivity of Fe in this wavelength region. In this paper the temperature dependence of spectral emissivity of Fe and related transition metals are studied experimentally and theoretically.
The analysis of temperature dependence may clarify the fundamental properties of the emissivity of metals. For example it is observed that the emissivity of Au increases with temperature both in the visible and infrared regions. In the visible region the increase in emissivity can be explained by a shift of the optical absorption edge of a bound electron and in the infrared region the increase is explained by a change in electrical conductivity.
The emissivity of transition metals such as Fe in the near-infrared region is affected doubly by the dispersion of bound electrons and by that of free electrons. To analyse this property, the author introduced a classical Drude-Lorentz dispersion model, based on the following study.
By the analysis of total emissivity, it is proved that the ratio λ_τ/σ in the Drude model is independent of temperature difference, where λ_τ is the characteristic wavelength and σ is the static optical conductivity.
By the measurement in the visible region, it is found that emissivities are proportional to λ^-2, Where λ is the wavelength. This property is similar to the reflectivity spectrum obtained by the Lorentz dispersion model. This may justify the adoption of Lorentz model to calculate the emissivity of metals.
The most interesting phenomenon of the emissivity in the near-infrared region is the presence of so called “X point”, or zero temperature coefficient, which is reported by many researchers. This phenomenon is recognized as the essential property of the emissivity of metals. By using Drude-Lorentz model, the X point can be interpreted as follows:
Under the constraint of the dispersion parameters (K_i>10, λ_τ/σ=constant), Lorentz dispersion acts on the emissivity in the visible region and Drude dispersion acts on it in the infrared region separately. The boundary of these two dispersion models appears in the near infrared region, and in this region, the emissivity is little affected by changing the dispersion parameters, or the minimum temperature variation occurs.
Thus it is concluded that the essential characteristics of emissivity for transition metals is not the presence of the X point, but the week-interaction between the Drude dispersion term and Lorentz dispersion term. It is clarified that the temperature variations for the observed emissivities of transition metals could be closely agreed from the visible to infrared wavelength regions with the Drude-Lorentz model.

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In order to make clear the elastic deformation of a single flat spring fulcrum used in the scales, the authors introduced the fundamental differential equations dl'=dθ/x and xdx=sinθdθ in the first paper¹⁾. To solve these equations, in the case of a small declining angle of scale levers, the authors assumed-sinθ=θ in the same paper. The results were testified experimentally as reported in the second paper²⁾.
In this third paper, to obtain the relations which are necessary in a large inclination angle of levers, the authors solve the fundamental equations by assuming sinθ=θ-(θ³/6).
The effects of the higher order term (θ³/6) upon every quantity which is necessary to design scales are estimated exactly, and it is shown that they are small even when the angle θ is about 0.5 radians.
To verify the theory empirically, the authors examine the relationship between the inclination angles of the flat spring at the upper and lower ends. In this case, they change the inclination angles φ at the upper end from-0.5 rad to +0.5 rad. They also study the shapes of flat springs in various caces by taking photographs of them. The agreement between theory and experiment is satisfactory.

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The switching characteristic of the unvented wall reattachment fluidic device is very much affected by the load. Generally, the larger the load resistance is, the smaller the switching control flow rate becomes.
In this paper, firstly we investigate experimentally the mechanism of such a switching, the load switching, to establish its theoretical treatment. We make it clear that the main jet detaches from a side wall over to the opposite wall when the pressure gradient along the reattachment wall becomes positive everywhere downstream of the reattachment point under the effect of the pressure rise caused by the load. On the basis of this result, we formulate a switching criterion and develop an analytical model of the load switching.
The calculated results can satisfactorily predict the load switching phenomena for a given geometry and load condition of the device, and are useful for analysis and design of the unvented wall reattachment devices.

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In this study, the authors investigate oscillations occurring in a loaded oscillator with long output channels. A mathematical model for the oscillator (a distributed parameter model) is introduced and analysed by a graphical method. As the results, it is found that a series of oscillations with step-wise wave forms occurs in the oscillator. The oscillation has a rectangular wave form with equal pulse widths when the impedance of the output channel Z is large (or the power jet flow Qs is small), but for the small impedance the wave form becomes step-wise and the number of the step involved in a period increases with a decrease of Z (or an increase of Qs). The oscillation having 2n steps in a period is termed the “oscillation in stage n”, the frequency of which is c/4nL (n=1, 2, 3, …), where c is the velocity of sound and L is the length of the output channels. The condition of occurrence of the oscillation in stage n and the amplitude are investigated analytically.
Furthermore, it is pointed out that two odd types of oscillation can occur when an initial large disturbance is applied to the flow in the output channels. They have wave forms diffrent from the step wise oscillation mentioned above, and have a rectangular wave form with irregular pulse widths which are determined by the initial disturbances. One of the odd oscillations has a frequency c/4L and the other c/2L. The theoretical results are supported experimentally.

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In the previous paper, the effects of the 2nd harmonics of synchro electrical error were discussed. The unbalance factors K, δ were defined and an optimum condition was shown on the K-δ diagram.
The synchro system error of a synchro transmitter (CX)-control transformer (CT) system, is normally considered to be superposed synchro electrical errors of the both components. In the event that 2nd and higher harmonics of the electrical error are negligibly small, the synchro system error could be given as the difference between the electrical errors of CX and CT.
In this experiment, the system error between CX with given K and CT with given is defined in its suitable domain on the K-δ diagram. It is shown that the presence of an imbalance of induced secondary voltage in the 3 phase windings, and higher harmonics due to slots' number n of iron core, cause the (n±1) th harmonic error.
The synchro system error of a torque synchro, i. e. the receiver error contains a backlash error. Experiments show that adding about one and a half of mean backlash error to the peak-to peak value of electrical error results in the maximum width of the receiver error.

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This paper reports on the parallel running system which consists of an induction motor, a diesel engine, a gear train, and a loading generator. The two power sources are coupled rigidly in parallel to the loading generator through the gear train.
Usually, the torque output characteristics of a diesel engine are expressible by those of a constant-speed type because of the presence of the governor. The characteristics values, namely the speed droop rate and the speed without loading, are matched to the induction motor. The author evaluates the flexibility in the output characteristics of a diesel engine without a governor, which are constant-torque type characteristics for each rack stroke of the fuel injection pump. And the engine without a governor is coupled to the induction motor. Thus, the induction motor operates as the dominant power source in the system. The loading ratio of the power sources depends on the gain-constant of the servo-system that manipulates the rack stroke with adequate relations to the motor current. It is quite easy to change the loading ratio by selecting the gain-constant of the servo-system, while the system is in operation. In the paper, some additional notes on the system synthesis are included.

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A new analyzing system for the laser Doppler velocimeter is proposed and constructed by employing the period-measuring method and inversing ROM. Its characteristics and accuracy are discussed in detail. Since it has a sufficiently high sampling rate compared with other analyzing systems, a lot of data can be easily accumulated in short time. These data are stored into the IC memory in a form of the probability density function of beat frequency or period, from which the mean flow velocity can be obtained with high accuracy. A combination of this system with a laser Doppler microscope makes it possible to measure the pulsated blood flow in arteriol. An example of measurement, in vivo, of pulsating blood flow in arteriol with a diameter of about 40μm on the memblance in web of a frog is shown to assure the usefulness of the present system constructed.

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In this paper, a dynamic model is presented to describe how the environmental pollution is related to the growth of economy accompanied by technological development. The optimal trade-off between pollution and consumption is studied. The optimal control under several constraints is discussed on the basis of the model. Some numerical results are also shown.

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