| JaLCDOI | 10.18926/15780 |
|---|---|
| FullText URL | Mem_Sch_Eng_OU_15_2_119.pdf |
| Author | Kaneda Masahiro| Akahori Ichiro| Egusa Masanori| Kuraoka Hiroaki| |
| Abstract | A high speed and high accuracy simulator whose data-handling is light and whose weak stability is assured even for stiff systems is discussed. This work is a part of CAD package : CADPACS-T which has been under development for the purpose of designing control systems utilizing TSS of a large scale digital computer in our laboratory. This simulator realizes high accuracy, high computational speed and high reliability adopting A-stable extrapolation methods to transform into a difference system, a recursive formula of an output interval to solve the difference equation, automatic choice of an optimal step length such that minimizes an predicted error, and evaluating error bounds closely near the actual errors in the point of numerical calculation. Moreover, in the point of data management, this realizes separation of program modules from data, common utilization of data and separation of investigation from simulation. |
| Publication Title | Memoirs of the School of Engineering, Okayama University |
| Published Date | 1981-03-30 |
| Volume | volume15 |
| Issue | issue2 |
| Start Page | 119 |
| End Page | 132 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307465 |
| JaLCDOI | 10.18926/15729 |
|---|---|
| FullText URL | Mem_Sch_Eng_OU_13_239.pdf |
| Author | Taniguchi Takeo| |
| Abstract | In this paper the minimum fill-in problem which arises at the application of the sparse matrix method for linear sparse systems is discussed from the graphtheoretic viewpoint and the author gives some results which can be directly introduced in the design of, so called, the optimal elimination ordering algorithm which gives the minimum fill-in(the number of zeros in coefficient matrix which become non-zero during the elimination process). Through this investigation only graphs are treated instead of the coefficient matrices for linear systems, and the elimination process for a matrix is equivalated to the vertx eliminations for the graph. Then, the results by the theoretical investigation are summarized as following: 1. Optimal elimination for each subgraph which is subdivided appropriately from whole graph leads to the global optimum. 2. In each subgraph there are only two kind of eliminations. Furthermore, some numerical experiments show the characteristics of the subset of vertices, which subdivide a subgraph from the residual. |
| Publication Title | Memoirs of the School of Engineering, Okayama University |
| Published Date | 1979-03-05 |
| Volume | volume13 |
| Start Page | 239 |
| End Page | 248 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307617 |
| JaLCDOI | 10.18926/15721 |
|---|---|
| FullText URL | Mem_Sch_Eng_OU_12_53.pdf |
| Author | Fujitsuka Takeshi| Agusa Toru| |
| Abstract | In recent years, the development of a high power transistor element is proceeding. A high power inverter circuit using power transistors are finding a good number of applications in induction heating and melting. Turn off time of power transistors occupies 5-lOμs of switching characteristics. A driving method to give base inputs for a half period is widely used for a inverter circuit. But this method has the following defects, the short-circuit current flows through two transistors because the other pair transistors turn on before one pair transistors turn off. So the switching loss is increased, the maximum output and the efficiency are decreased. In this paper, a driving method to give base inputs for the less period as compared with a half period is discussed. Using this method, the foregoing defects is lost and the driving frequency is able to become higher. In addition, it become clear that the square waveform output is given using this method in the case of R-L load. |
| Publication Title | Memoirs of the School of Engineering, Okayama University |
| Published Date | 1978-02-25 |
| Volume | volume12 |
| Start Page | 53 |
| End Page | 58 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307552 |
| JaLCDOI | 10.18926/15575 |
|---|---|
| FullText URL | Mem_Sch_Eng_OU_2_43.pdf |
| Author | Takahashi Teruo| Fujita Kozo| |
| Abstract | In this report, the analogies of the maximum allowable liquid and gas velocities in various countercurrent gas-liquid contactors of column type are considered analytically. That is, by plotting the flooding points of various columns in a gas-liquid separated coordinates, the similar curves have been obtained in each column. Because the difference of these curves is due to the shape of each column, the difference of each shape must be corrected and evaluated as a ahape factor. Then, by containing this factor in coordinate variables, various flooding points in each column may be correlated by a single curve. If this correlation curve is used, the flooding velocity can be estimated easily, and the maximum allowable liquid and gas velocities in these countercurrent contactors of column type can be compared. |
| Publication Title | Memoirs of the School of Engineering, Okayama University |
| Published Date | 1967-04-01 |
| Volume | volume2 |
| Issue | issue1 |
| Start Page | 43 |
| End Page | 49 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307818 |
| JaLCDOI | 10.18926/15649 |
|---|---|
| FullText URL | Mem_Sch_Eng_OU_7_1_43.pdf |
| Author | Kaneda Masahiro| |
| Abstract | This paper deals with a parameter estimation method which yields the more suitable estimate of the parameter using noisy data or measured values. The estimation method is one that uses a kind of a weighted mean, and weighting at taking a weighted mean is interested in particularly. That is to say, as the grade of 'more suitable' depends upon the weighting, we can obtain the more suitable estimate by choosing the weighting coefficients suitablly. When the function which yields the estimate using finite measured values, i.e., the estimator is a particular form, sub-optimal weighting in the practical sense is discussed. Here, the concept of 'optimal' implies that the variance of the final estimate is minimum. And the particular form is one that both the denominator and the numerator of the estimator are first order formulas or second order formulas of finite measured values. And two theorems in relation to this problem are proposed and proved. Moreover, for an exsample of application of these theorems, a parameter estimation method is dealt with, which estimates the parameters of the pulse transfer function of a control system using the sampled measured values of the impulse response of that system. |
| Publication Title | Memoirs of the School of Engineering, Okayama University |
| Published Date | 1972-07-10 |
| Volume | volume7 |
| Issue | issue1 |
| Start Page | 43 |
| End Page | 48 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307213 |
| JaLCDOI | 10.18926/15748 |
|---|---|
| FullText URL | Mem_Sch_Eng_OU_14_2_53.pdf |
| Author | Nishigaki Makoto| Kono Iichiro| |
| Abstract | The purposes of this paper are primarily to research on behavior of groundwater flow in saturated and unsaturated zone, and to present the fundamentals of the theory of groundwater flow. This paper discusses the physics of the saturated-unsaturated groundwater motion. Evaluations confirm the early belief that Darcy's law is of the nature of statistical result giving the empirical equivalent of Navier-Stokes equations. The governing equation of saturated-unsaturated flow in porous media is derived from the law of mass conservation and from the Darcy's law and Richard's equation of motion and is compared with the Klute's diffusion equation which has been widely used in the analysis of unsaturated flow. As a result; it is concluded that the governing equation has the advantage that can be applied for the whole flow region. Typical boundary conditions are enumerated. |
| Publication Title | Memoirs of the School of Engineering, Okayama University |
| Published Date | 1980-03-01 |
| Volume | volume14 |
| Issue | issue2 |
| Start Page | 53 |
| End Page | 72 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307170 |
| JaLCDOI | 10.18926/15798 |
|---|---|
| FullText URL | Mem_Sch_Eng_OU_19_2_33.pdf |
| Author | Taniguchi Takeo| Mitsuoka Kazuhiko| Terada Takashi| |
| Abstract | This paper treats the convergence condition of the explicit finite element method (i.e. the time and spatial axes are discretized by using the explicit finite difference method and the weighted residual method, respectively) which is applied for analyzing the heat problem in region with complex boundary configuration and also with several material properties. The main role of this study is the application of the Brauer's theorem. As the results we obtain that the usage of the Brauer's theorem is valid and that the application method of the theorem is presented in this paper. |
| Publication Title | Memoirs of the School of Engineering, Okayama University |
| Published Date | 1985-02-25 |
| Volume | volume19 |
| Issue | issue2 |
| Start Page | 33 |
| End Page | 48 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307201 |
| JaLCDOI | 10.18926/15829 |
|---|---|
| FullText URL | Mem_Sch_Eng_OU_21_1_17.pdf |
| Author | Akagi Fumio| Osaki Hirokazu| |
| Abstract | Assembly line balancing is to assign work elements to serial work stations so as to make the work content at each station as close as possible to one limiting cycle time or pitch time, i.e., an upper time limit over every station. Until now, it is usually assumed that the performance rates of work stations are constant. But in practice the performance abilities of workers, machines or robots are varied by their own working conditions. Then the actual station times are different from standard ones, and consequently the line balance may diminish in many cases. Therefore in this paper, we propose an improved balancing method, in which work elements can be assigned to the work station having the upper time limit changed by its performance rate or ability. Further we develop the computer program of the proposed method and provide an illustrative problem and computational results. In an application of our method to the practical problems, it is shown that the actual efficiency of the production line becomes near that planned. |
| Publication Title | Memoirs of the School of Engineering, Okayama University |
| Published Date | 1986-11-15 |
| Volume | volume21 |
| Issue | issue1 |
| Start Page | 17 |
| End Page | 30 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307409 |
