This paper gives, for the case where only one independent variable of the considered 2D (2-dimensional) systems is unbounded, a formulation for 2D model-following servo problem. That is, to determine a control input such that the outputs of a given 2D plant asymptotically track, with tracking error as small as possible, the step response of a given 2D model system as the unbounded variable approaches infinite. It is shown that this problem can be transformed into an equivalent 1D LQR problem, and thus can be essentially solved by 1D the-ory. The relationship between the solvability conditions obtained for the equivalent 1D system and the practical stabilizability and detectability of the original 2D plant is clarified. A numerical example is also shown.

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This paper deals with an application of a simplified adaptive pole placement control algorithm to a design of active vibration control system. The algorithm is examined by several experimental results.

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A functional equation Σ^m_i=1a_iu(φ_i(z)) = f(z) is considered, where {φ_i(z)^m_i=1 are holomorphic functions in a neighborhood of z = 0 with φ_i(0) = 0 and f(z) is holomorphic in a sector with vertex z = 0. It is shown under some conditions of {φ_i(z)^m_i=1, f(z) and {a_i}^m_i=1 that the equation has a formal power series solution that is Borel summable.

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In this paper, we treat the repetitive control for linear mechanical systems in the discrete domain. First, we investigate the stability of the repetitive control system using the basic feed-back control theorem and note that the stability condition can be related to the positive real condition. We next propose an available control algorithm based on the concept of positive real property for the plant whose transfer function is not positive real (e.g. a strictly proper transfer function). The value of parameters in the algorithm can be found by using the Nyqist plots. We also discuss the characteristics of the designed system and present some results of hybrid computer simulations for a mechanical system. It is shown that the designed repetitive control system is insensitive to changes in plant parameters and the error converges in spite of the high frequency of the reference signal.

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We derive the performance measures for non-priority customers in a priority single-server queue with two types of Markovian arrival processes (MAPs). One type of customers has preemptive resume (or repeat) priority over the other. We regard the model with two types of MAP arrivals as an MAP/SM/1 queue with only non-priority customers arrivals, semi-Markovian service times and some server vacations. Performance measures such as the waiting time distribution and the queue length distribution are represented by matrix exponential forms. Our model cannot assume i.i.d. services or i.i.d. server vacations and, in addition, the vacation length depends on the service process. Thus, our formulas give new insights on existing results concerning an MAP/SM/1 queue with i.i.d. multiple server vacations.

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In this paper, we propose a time domain design of the deadbeat digital controller with series compensation of the integral-action and local feedback compensation. It is proved that the control system proposed here gives the deadbeat response not only for the step change of the desired value but also the disturbance, and the simulation result makes the fact clear.
The dynamic characteristic of the process is expressed by the step or impulse response, then the sequence of the control signal which makes deadbeat response can be easily obtained by the matrix computation, using sampled data of these responses. The designing method of the integral-action gain constant and feedback compensator is derived by using the sequence of the control signal.
This method is very simple comparing with other methods which use the pulse transfer function or state equation, and can be systematically applied to the system including the lag time or the restriction of the manipulated variable.

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In this paper, are discussed a determination method of weighting matrix of quadratic performance index and a design method of optimal deadbeat control system. First, the relationship between weighting matrix of quadratic performance index and extra pole of over-parameterized pulse transfer function model is indicated. Next, a design method of optimal deadbeat control system is explained. Lastly, to demonstrate the effectiveness of the proposed method, some numerical examples are also presented.

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A chemical sensing system that uses a new type of sensor film and digital signal processing of their dynamic responses is described. This system consists of quartz crystal microbalances coated with plasma polymer films. These films are useful due to their high densities of radical sites and unsaturated bonds, which interact with gas molecules. Impedance analysis shows that a plasma-polymer-film-coated sensor is a durable and stable microbalance. When this sensor array is exposed to a gas, the adsorption and desorption of the target gas causes dynamic piezoelectric responses. Because the sensor films have an affinity for several types of gas, signal processing is needed to discern unique gas information. To analyze its response, we represent it by a linear filter, which is often used for estimating the parameters of dynamic systems. This filter has coefficients that represent the sensor's transfer function and these provide pattern vectors that characterize the target gas for classification. This filter shows that recognizing and quantifying the components of a gas mixture are possible using our sensing system. It also shows that the system can identify the sensor's transfer function even when the gas concentration changes, by using two sensors with different dynamic properties. These results show that this chemical sensing system is useful in a wide range of applications, such as chemical analysis systems and fire alarm systems.

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In recent years, an adaptive control problem which has the unknown parameters and states has been actively examined, and many approaches have proposed recently. But most of those studies are done without any limitation of input amplitude.
In this paper, we deal with the problem of constructing an adaptive control system for a single-input single-output time-invariant discrete system with the limitation of input amplitude. In order to able to discuss this as linear problem for the plant with an amplitude limitation, we introduce a compensator called the dispersion filter, and the structure and its feature are explained in detail. Based on the prior information of the dispersion filter, two adaptive control schemes are proposed. At the end of this paper, the results of the simulation of a third-order unstable system are included in order to show the effectiveness of the proposed schemes.

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The modified repetitive control system is designed using a modified repetitive controller with a low-pass filter incorporated into the positive feedback loop for the time-delay element. The modified repetitive controller, however, functions only for the gain determined by the low-pass filter at the basic frequency as the desired value and the frequency obtained by multiplying it by integers. This problem can be solved by two methods: one is by using a modified repetitive controller with linear phase filter and the other by using a modified repetitive controller with corrected dead time.
This paper describes the results of our study about the above two methods to identify the differences between them in their control characteristics and formulate the guidelines for their use as summarized below:
(1) The modified repetitive controller with linear phase filter can basically function as well as the modified repetitive controller with corrected dead time only if its filter is of higher order. However, if the spectrum of the desired value is distributed over a wide frequency range, the use of a higher-order filter in the controller to increase its gain conversely results in narrowed frequency bandwidth, not providing so much improvement in its control performance as expected, and frequently presenting the practical problem of increasing the time required for the computation. Notwithstanding this, if the spectrum is locally distributed in a narrowed frequency range close to the basic frequency, an increase in the order of the filter used in the controller as allowed by the computation time enables its control performance to be improved.
(2) The modified repetitive controller with corrected dead time, even if its filter is of first order, can perform its control function comparable to that of the modified repetitive controller with higher-order linear phase filter. This controller is a practical control method, particularly having the great advantage of increasing its gain to^∞for direct current.

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Relations among several earthquake magnitude determination formulas were investigated by using data obtained by high resolution digital accelerometers. Digital accelerometer, JMA-87 type electromagnetic strong motion seismograph (ESM) which was recently deployed at 74 stations over the Japanese Islands by the Japan Meteorological Agency (JMA), is one of the wide-frequency band and large-dynamic range seismograph. Digital records enabled us to simulate any type of seismograms from the same data and to measure several maximum amplitude values for corresponding magnitude determination formulas. To evaluate consistency among the magnitude formulas, magnitude values from the same station were compared with each other in the present study. One of the advantageous points of the method is its independency from the influence of site condition and inhomogeneous attenuation along ray path on the observed amplitude.
As a first step, magnitudes which are derived from the Tsuboi's formula (M_T) and the JMA-EMT formula (M₆₇ or M₇₆), both of them are employed as standard JMA magnitudes, are compared with each other. M_T is calculated from the maximum amplitude of horizontal ground displacements recorded by medium period seismograph (JMA-59 type and JMA-S type, T=5s) and M₆₇ and M₇₆ are from the maximum amplitude of vertical ground velocity recorded by short period seismograph. JMA's magnitude is given as a arithmetic mean of both formulas. Although JMA-EMT formula was designed as a substitute of Tsuboi's formula for smaller earthquakes which can be recorded only by sensitive short period instruments, as several studies have already pointed out, it is consistent with Tsuboi's formula only in a narrow magnitude range. Compared to the Tsuboi's formula, while the JMA-EMT formula provides smaller magnitude values for larger earthquakes, it gives larger values for earthquakes which magnitudes are less than 3 and discrepancy increases as the size of earthquake becomes smaller. Introduction of a coefficient to the formula which adjusts the relation between magnitude value and logarithm of maximum amplitude value seems to be indispensable to correct the discrepancy.
Beside the coefficient, constant in the EMT formula depends largely on conditions of installation sites. Otherwise, borehole installation in a hard basement gives smaller magnitude value and surface installation on an alluvial soil basement gives large magnitude value. Classification of site effect is important to determine appropriate constant for EMT formula.
As a second step of this study, it is indicated that amplitude data within 50km epicentral distance provide smaller magnitude values for both Tsuboi's formula and EMT formula. The EMT formula also gives smaller magnitude value for data beyond 200km epicentral distance. There by, the study shows importance of appropriate selection of epicentral range for applying the formula.
Finally relation between JMA's magnitude and Richter's local magnitude (M_L), which is the oldest magnitude scale and of the international scale, was investigated by using simulated Anderson-Wood seismograms. Results show that M_L from simulated seismograms is generally larger than M_T for smaller earthquakes. However, difference becomes smaller as earthquake magnitude becomes larger.

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