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Volume 28, Issue 9
Displaying 1-18 of 18 articles from this issue
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Yasumitsu KURANO, Kiyoshi YOSHIDA1992 Volume 28 Issue 9 Pages 1023-1028
Published: September 30, 1992
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSA falling sphere viscometer, which is capable of absolute measurements of the viscosity of reference liquids at pressures up to 500MPa with an error less than ±0.5%, has been designed and constructed. The falling-time of sphere can be measured automatically using two laser beams through the windows on the high pressure vessel of the viscometer. The sphere is returned to its starting position by rotation of the high pressure vessel.
This paper describes the construction and the principle of operation of the falling sphere viscometer. The results of evaluation of the viscometer's performance obtained by measurement of the viscosities of reference liquids, namely the Standard Liquids for Calibrating Viscometers, are also described.View full abstractDownload PDF (1269K) -
Hiroyuki EHARA, Eiji OKADA, Yoh SHINOZAKI, Haruyuki MINAMITANI1992 Volume 28 Issue 9 Pages 1029-1037
Published: September 30, 1992
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSUnlike blood circulation which has a pump organ like a heart, lymph circulation has no pump organ. In the lymph circulation, lymph vessels contract and expand like pumps. And this is considered main propulsion of lymph flow. But, the relationship between the changes in the velocity of the lymph flow and the diameter of the lymph vessel has not been clarified.
A flow velocity measuring system and a video tape recorder system were connected to an intravital microscope in parallel. This system was used to measure the changes in the velocity and the diameter in micro lymph vessels at the same time. An optical-fiber-array spatial filtering velocimeter was applied to the flow velocity measuring system. Since structure of a spatial filtering velocimeter is simple, it is suitable to connect a microscope. The optical-fiber-array spatial filtering velocimeter was tested both in vitro and in vivo.
The lymphocyte velocity and the diameter of micro lymph vessels in rat mesentery was measured by the system. As results, the maximum forward velocity was 8.0mm/s and the maximum backward velocity was 2.0mm/s, and the velocity of lymphocyte flow was changing during the period of 2.5 to 5.0 seconds. The changes in the velocity of lymphocyte flow were highly correlated with the contraction and the expansion of the lymphvessel.View full abstractDownload PDF (2568K) -
Tetsuya SHIMAMURA, Jouji SUZUKI1992 Volume 28 Issue 9 Pages 1038-1045
Published: September 30, 1992
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn this paper, we propose an approach to two-dimensional spectral estimation, which involves input-dependent FIR prefiltering. This approach is an iterative algorithm in which the design of two-dimensional zero-phase FIR filter and the operation of spectral estimation are sequentially performed. Although we use the periodogram for the purpose of calculating the power spectrum, an introduction of the input-dependent prefiltering leads to high spectral resolvability and reduced estimation variance. Any conventional Fourier-based method did not provide the both simultaneously. Also, the computational time wasted on this approach is moderate, since we can utilize iteratively the computational efficiency of the two-dimensional FFT algorithm. The effectness of the spectral estimation algorithm is shown by computer simulations.
Furthermore, the two-dimensional spectral estimation approach could be extended to the multidimensional version. The extended algorithm would provide similar properties to those of the two-dimensional algorithm.View full abstractDownload PDF (1629K) -
Katsuji UOSAKI, Michio YOTSUYA1992 Volume 28 Issue 9 Pages 1046-1051
Published: September 30, 1992
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSRecently, several adaptive identification methods have been developed for non-stationary stochastic systems. Among those, much attentions have been paid to the use of an adaptive (time-varying) forgetting factor depending the level of alertness of the systems to estimate the time-varying parameters. However, its adjustment is usually complex and time-consuming. We propose in this paper an adaptive identification method called multiple forgetting factors method (MFF method) for non-stationary linear stochastic systems with time-varying parameters. The parameter estimates are constructed as a weighted sum of the estimates obtained by multiple recursive least squares methods operating in parallel with a constant forgetting factor. The weights are adjusted to fit the time variation of the parameters using modified Bayes rule. Thus, the identification method has a simple structure and is quite easy to implement. It is shown by simulation experiments that the proposed method works well not only for systems with gradually changing parameters but also for systems with abruptly changing ones.View full abstractDownload PDF (898K) -
Zenta IWAI, Ikurou MIZUMOTO, Katsumi ADACHI, Hiroshi DOUZONO1992 Volume 28 Issue 9 Pages 1052-1060
Published: September 30, 1992
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSTo Control the large-scale systems centrally is difficult due to an interconnection of subsystems with unknown parameters, nonlinerities, and disturbances. Decentralized adaptive control schemes are an effective method to handle these uncertainties.
In this paper, we consider a decentralized adaptive control based on simple adaptive control (SAC) method which possesses simple adaptive controller structure and robustness for disturbances. It is verified that, the boundedness of all signals of the systems is guaranteed if the M-matrix condition or range condition of interconnections is satisfied. The effectiveness of this method is examined by using parallel inverted pendulums example.View full abstractDownload PDF (1326K) -
Masahiro OYA, Toshihiro KOBAYASHI1992 Volume 28 Issue 9 Pages 1061-1070
Published: September 30, 1992
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSWe consider systems with bounded disturbances. In the case where the relative degree of transfer function is more than three, we propose a design method of a robust adaptive control system. The design purpose in this control system is to construct a control system so that the output error between the output of a object and a desired signal can converge to any small region with any degree of stability.
A precompensator with varying parameters is constructed in order to establish the design purpose. And a parameter observer is constructed by using of the σ modification method in order to estimate the disturbances and the unknown parameters. The design purpose can be established by means of constructing the input of the precompensator by using of the estimated parameters. Then we derive the relation equation between the design parameters and the norm of output error. From this relation it is shown that the performance of the control system can be improved easily by using of two design parameters. In this control system if no disturbance exist, it is shown that the output error converges to zero like as traditional model reference adaptive control systems. It is also shown that the performance of the control system can be improved easily in the same way as the case where disturbances exist. Moreover the boundedness of the control system is presented in order to show that the control system prementioned can be constructed in practice.
Finally, computer simulation results are presented to illustrate the effectiveness of the proposed method.View full abstractDownload PDF (1795K) -
Kou YAMADA, Keiji WATANABE1992 Volume 28 Issue 9 Pages 1071-1076
Published: September 30, 1992
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper is concerned with the robustness of the control systems in the presence of perturbation of disturbance driving matrices. A concept of equibalent disturbance is introduced. It is shown that the nominal plant is robust to the perturbation if the transfer matrix from disturbances to outputs does not have any poles and zeros on imaginary axis.View full abstractDownload PDF (607K) -
Fuke WANG, Yi-sheng ZIIONG, Toshio EISAKA, Ryozaburo TAGAWA1992 Volume 28 Issue 9 Pages 1077-1083
Published: September 30, 1992
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn the practical systems, there exist saturation limitations on the control input. Control systems designed without considering the input saturation not only deteriorate the control system performance, but also possibly, lead to loss of stability.
In this paper, a new design method of control systems is proposed for the plants with input saturation. Control systems designed by this method reduce the influence of the input saturation. Particularly, both the stability in the large and the asympototic convergency of the outputs to the ones of systems without input saturation can be guaranteed.
First, the design method of the controller in which a nonlinear element involves is preseted. Then the stability and the convergency property of the proposed control system are proved. Finally, numerical examples are presented to illustrate the effictiveness of the proposed method.View full abstractDownload PDF (1268K) -
Masahiro OYA, Toshihiro KOBAYASHI1992 Volume 28 Issue 9 Pages 1084-1093
Published: September 30, 1992
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSWe consider nonlinear systems which consist of nonlinear characteristics in the input and the output. It is assumed that the signals of the input and the output are only available, and we propose a design method of a control system in which the output error between the output of the object and a purpose signal converges to any small region.
In the case where the relative degree of the linear element of the object is one it can be shown that the control system can be constructed by using of unity feedback of the output error. Namely we present sufficient conditions which nonlinear characteristics have to satisfy in this control system, and we derive the quantitative relation between the feedback gain and the output error. From this relation it is presented that the design purpose can be established. In the case where the relative degree is more than one the design purpose can not be established by using of unity feedback of the output error. Therefore a high gain feedback control system is constructed by using of the state observer. In this control system, it can be shown that the control purpose can be established if nonlinear characteristics satisfy the sufficient condition above mentioned. Namely we derive the estimated equation of the output error. From this estimated equation it can be presented that the output error converges to any small region by increasing only one of design parameters.
Finally, computer simulation results are presented to illustrate the effectiveness of the proposed method.View full abstractDownload PDF (1243K) -
Kiyotaka SHIMIZU, Taro TAMURA, Masataka HANABUSA1992 Volume 28 Issue 9 Pages 1094-1102
Published: September 30, 1992
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSA simple derivation of the Riccati inequation for H∞ control by state feedback is presented. It is proved by solving the LQ-max problem, which is equivalent to the H∞ norm condition such that the uniform norm ||Tvz||∞ of a transfer operator T from a disturbance v to an output z is less than a specified value γ. The proof is made in a direct and self contained manner with state space representation.View full abstractDownload PDF (1058K) -
Li XU, Takatoshi IKEDA, Osami SAITO, Kenichi ABE1992 Volume 28 Issue 9 Pages 1103-1110
Published: September 30, 1992
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn many practical situations, the independent variables i1, …, in of an nD signal x(i1, …, in) are bounded spatial variables, except that perhaps one is the unbounded temporal variable. Taking this feature into account, Agathoklis and Bruton developed the concept of practical-BIBO stability for nD discrete systems, and showed that the conventional-BIBO stability conditions are too restrictive for many applications.
This paper deals with the problem of feedback practical-stabilization of nD discrete systems whose input and output signals are unbounded in, at most, one dimension. A constructive algorithm is first presented for solving Bezout equation over the ring of practically-stable rational functions. Then, a necessary and sufficient condition for an nD system to be practically-stabilizable is derived and the parametrization of all nD practically-stabilizing compensators is given. These results make it clear that the nD practical-stabilization problem can be essentially solved by using 1D approaches.View full abstractDownload PDF (1318K) -
Search of the Best Plan by Using a Genetic AlgorithmShigeyuki SAKANE, Toshiji KURUMA, Toru OMATA, Tomomasa SATO1992 Volume 28 Issue 9 Pages 1111-1117
Published: September 30, 1992
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSVisual monitoring of an object manipulated by a multi-fingered hand has a problem of occlusions caused by the fingers. In this paper, we present a new planning method, based on the 3-dimensional model of the environment, to focus attention in such a monitoring task. We formulate the planning of focus of attention as a scheduling problem for the whole task period rather than for a specific time. We introduce a Genetic Algorithm to cope with a combination explosion of the image features considered at all time steps. The Genetic Algorithm is a population based search method which finds solutions efficiently in a large search space by simulating some features of biological evolution. The algorithm consists of selection, crossover, and mutation procedures. To solve the planning problem, we have implemented the algorithm using a coding scheme for a gene to produce consistent offspring after the crossover. Experimental results demonstrate the usefulness of the proposed method by finding the pseudo optimal plan within a short computation time.View full abstractDownload PDF (1467K) -
Syohei ISHIZU1992 Volume 28 Issue 9 Pages 1118-1124
Published: September 30, 1992
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn complex decision making such as ill-structured decision making, one of the main problems is how to treat ambiguous aspects of the decision making. According to the complexity of the objective systems or processes, many types of evaluation attributes are necessary for the rational decision and the relationships among the attributes become complex ones. Especially some phenomena of hierarchical evaluation or switching of evaluation attributes are emerged in the decision processes. In such a situation, decision maker should investigate the properties of the evaluation attributes.
One of the main objectives of this paper is to clarify structural knowledge about evaluation attributes in order to make complex decision rationally and effectively. In this paper, first we present a framework in which we can investigate properties of evaluation attributes formally and refer to the situation of switching evaluation attributes in the decision processes. Next, we analyze relationships among evaluation attributes as dependency. Finally we refer to hierarchical evaluation structure of attributes based on the above framework.View full abstractDownload PDF (1391K) -
Minoru YONEDA, Satoru FUKAMI, Michel GRABISCH1992 Volume 28 Issue 9 Pages 1125-1134
Published: September 30, 1992
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThe feature of ill-defined problems is that they cannot be described by a mathematical model. This type of problem has only qualitative relations between state variables. When we evaluate state variables of the object system, we have to evaluate the body of related state variables. Therefore, the purpose of this paper is to propose a new evaluation and decision method based on possibility-valued fuzzy integral. In our method, scenarios are represented by fuzzy propositions in which subjects are state variables. The values of state variables are described by a possibility distribution. Using the extension principle, the possibility-valued fuzzy integral (Choquet Integral) can represent the evaluation of the scenarios and the status of the object system. As the results of ranking the evaluation values (possibility-valued), we decide to choose the most suitable scenarios.
The foreign exchange transaction system was chosen to provide a practical example. It is a typical ill defined problem. The structure of our system is comprised of three parts: a group of states, scenario evaluation and a generator of states. This system has two types of input: numerical data (e. g., economic index) and text data (e.g., news, speech of VIP, etc.). A state includes a level that represents the economic status (e.g., US interest is high) by a possibility distribution. Moreover, evaluation based on the fuzzy integral is proposed for scenario evaluation. This integral value can be integrated as a total evaluation of a scenario, the fuzzy measure as a subjective weighting and the integrand as a degree of matching between the level and a proposition in a scenario. As a result, information of increased importance is now suggested.
In this paper, we have built the new decision method based on fuzzy theory. We can say that this method is very useful for many ill-defined problems.View full abstractDownload PDF (1722K) -
Yasumasa FUJISAKI, Masao IKEDA1992 Volume 28 Issue 9 Pages 1135-1137
Published: September 30, 1992
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSWe consider a two-degree-of-freedom servosystem for constant reference signals, in which the integral effect does not appear if there is no plant perturbation or no disturbance input. We show that by tuning the gain of the integral effect, we can reduce sensitivity of transient responses to plant perturbations and disturbance inputs.View full abstractDownload PDF (356K) -
Hiroyoshi HIRAI, Hajime MAEDA, Shinzo KODAMA1992 Volume 28 Issue 9 Pages 1138-1140
Published: September 30, 1992
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper discusses the difference between the solutions of weighted H∞ and H2 optimal control problems. It is shown that the H∞-solution approaces H2-solution for all frequency in the pass band, if the cut-off characteristic of the weight function tends to the ideal one.View full abstractDownload PDF (295K) -
Yoshihiko MIYASATO1992 Volume 28 Issue 9 Pages 1141-1143
Published: September 30, 1992
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSA design method of model reference adaptive control for non-minimum phase systems with time delays is proposed. The poles and zeros of the systems are relocated by the periodic time-varying feedback control with multirate sampling.View full abstractDownload PDF (329K) -
1992 Volume 28 Issue 9 Pages 1144
Published: 1992
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSDownload PDF (26K)
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