vol.20 (2007)

Bulletin of Research Center for Computing and Multimedia Studies
Vol.20, 2007 ISSN 1880-7526 Published March 20, 2007

Lamination Order of Composition Material of Space Debris Shield
Masatomo Nakagami,Masahide Katayama,Kazuyoshi Arai
PDF   Abstract
The purpose of this study is to develop a lightweight small compound shield for the space structure, which defends the space debris impact. Aluminum alloy(A6061-T6 )and polycarbonate as shield composition materials were used, and impact tests were conducted for laminated shields of these materials. The effects of a lamination order on the ballistic limit velocity of the shield were investigated considering the plate bending deformation.
Numerical Analysis of Flow within Ultra Micro Centrifugal Compressor
Kazuaki Hagiwara,Takashi Amano,Naoki Shimada,Shimpei Mizuki,Hoshio Tsujita
PDF   Abstract
In recent years, a lot of experimental and numerical investigations have been made for the micro centrifugal compressor system used as the mobile electrical power source, the electric distributed energy source, the gas turbine for micro plane and so on. However, the downsizing of the centrifugal compressor system makes impossible to measure the internal flow in the rotating impeller experimentally. For realizing the micro centrifugal compressor, which constitutes a micro gas turbine, the internal flow in the micro centrifugal impeller was analyzed by CFD in detail.
Noise Reduction of Stepping Motor
Shogo Kurihara,Nobuhiro Matsumura,Mituo Iwahara,Akio Nagamatsu
PDF   Abstract
The purpose of the research is a noise reduction of stepping motor. The stepping motor the structure which rotates every step can simply realize position control, and it has velocity fluctuation by repeating acceleration and deceleration, and this becomes a factor in which the vibration is generated rotor. For the noise reduction, measurement of noise and vibration of stepping motor that structural optimization of stator and production of finite element model is tried structural optimization of entire stepping motor.
A Vibration Characteristic of a Rubber-ball Tennis Racket by Mode Analysis
Yasumi Yamaguchi,Yuta Goto,Mitsuo Iwahara,Akio Nagamatsu
PDF   Abstract
This study is a study about a soft tennis racket. Some studies advance about a general racket. However, a study is not made about a rubber-ball tennis racket. A mode analyzed a rubber-ball tennis racket in this study and investigated the characteristic.
The Research of the Cavity Resonance Using the Hollow Tube Made of the Titanium
Nobuhiro Matsumura,Taiki Kanamaru,Mitsuo Iwahara,Akio Nagamatsu
PDF   Abstract
In this present, the flight-distance performance of driver head was controlled by SLE rule which controls the restitution coefficient of driver head from remarkable technological innovation of driver head. This rule decides restitution coefficient of the stroke plane of the head is under 0.83. From this rule, it is difficult to make discrimination in the flight-distance performance of driver head. Then, feeling merit of the batting sound is noticed as new added value. In the product development, the method for predicting the sound by design stage is effective in order to pursue the sound quality, while time and cost are reduced. This study carried out the verification using the driver head in which this sound decided added value of products. As the previous step, we researched the cavity resonance study by using hollow tube made of the titanium.
A Study of Experimental Modal Analysis by Strain Gages
Takahiko Ito,Hiroki Kuwabara,,Mitsuo Iwahara,Akio Nagamatu
PDF   Abstract
A final purpose is determing vibration characteristics at the time of running for the rotating structure which had difficulty with the measurement by the experimental modal analysis that we used conventional acceleration pickup. Therefore we perform experimental modal analysis using strain gauges and find vibration characteristics. In addition, we find vibration characteristics from calculations and elucidate a vibration phenomenon from both sides of experiments and calculations.
A Study on Dynamic Analysis of Open Branched Structure Model
Munetaka Kiyoi,Motonori Nisikawa,Hirou Miura,,Nagayuki Yoshida
PDF   Abstract
This research defines the structure to be seen in the upper part of the trees and their roots as the open branched structure, and investigates its structural property. Its aim is to make clear the secret of the earthquake-resistance characteristics of a tree from the viewpoint of the engineering, and also to find out the useful information for the future of architectural structures. Because of that we create the mathematical model of trees based on the bibliographic search to other fields such as botany, and performed the dynamic analysis for the models.
Short Term Runoff Analysis Considering Rainwater Flowing Direction In Nogawa Basin
Takusari Hideaki,Oka Yasumiti,Kodera Koji
PDF   Abstract
Rainfall runoff analysis using distributed runoff model requires some important parameters relevant to basin characteristics. Among these parameters, this paper focuses on the “Land Incline Direction” which governs the surface runoff between meshes. After dividing basin into 10m square meshes, parameters abstracted from Digital Elevation Model (DEM), which represent the Land Incline Direction, are assigned to each mesh. Then, a runoff process model is constructed to evaluate runoff rate from the upper mesh to the lower. In addition, the distributed model is applied to Nogawa basin. Although satisfactory results have not been obtained yet, its performance and validity are planned to be assessed at the next stage by incorporating additional physical parameters and comparing the calculated results with the observed hydrological data.
Development of HPM which Used the Stress for Displaced Field
Norio Takeuchi
PDF   Abstract
In the existing HPM (Hybrid-type Penalty Method), independent rigid-body displacement, rigid-body rotation, and the strain are set as the unknown parameter of the displacement field for every sub-domain. In the case of the high order displacement field, the gradient of the strain is also taken into consideration. In this paper, it proposes the new displacement field which sets the stress as the unknown parameter instead of the strain as a displacement field of HPM. At the secondary displacement field, it also adds the gradient of the stress to the unknown parameter. The simple numerical examples show that the accuracy of the solution obtained by this technique is the same as the displacement field which assumes the strain in the unknown parameter.
Development of Mesh Dividing Method for HPM Used for Index of Division of Strain Energy
Riichi Mihara,Norio Takeuchi
PDF   Abstract
The authors proposed the new discretization technique which it calls the hybrid type penalty method (HPM). This method applies the concept of the penalty method on the basis of the principle of hybrid type virtual work. In HPM, it divides the whole domain into the sub-domain, and the displacing field is independently defined in each sub-domain. In this model, the node of the sub-domain is used only to recognize the configuration, and it does not have the degree of freedom like FEM. Therefore, in the problem that strong nonlinearity such as the yield appears locally, accuracy improves by dividing only the element into the small element. It introduces the element subdivision method of which the index is the strain energy in this research.
Simulation to Follow-Direction Method and Follow-Me Method at Emergency Evacuation
Yusaku Okada,Norio Takeuchi
PDF   Abstract
In this research, it reproduces in the simulation the follow-direction method which is the conventional evacuation method, and the follow-me method with which validity is shown field experimentally. We proposed the simulation model and the scenario for field experiment at emergency evacuation. The result of the simulation to the past filed experiment showed the experimental result well. The follow-direction method had to make the leaders walk speed late about 70%. As a result, more evacuation time required the follow-direction method from the follow-me method. It was able to check the validity of the follow-me method at the emergency evacuation.
Study of Passive Walker with Upper Limb
Ryota Mose,Sho Uchida,Hisato Kobayashi
PDF   Abstract
This paper analyzes a property of passive walking mechanism, which has upper body and arms, Though there are lots of studies on passive walkers, it is still unclear how its body posture and its upper limb’s motion affect its stability. By doing various kinds of computer simulations, we can derive an answer to the above open question; namely we can know the sinusoidal movement of the arms gives positive effect to the walking mechanism.
Visualization of Nonlinear Phenomena in Electrical Machines
Yuji Tanaka,Yoshifuru Saito
PDF   Abstract
This paper studies nonlinear phenomena caused by ferromagnetic materials to visualize a regularity of nonlinear systems. To represent nonlinear properties of ferromagnetic materials in parallel ferroresonant circuit, we emp
loy a Chua type magnetization model composed of the nonlinear parameters: permeability μ, reversible permeability μ, and hysteresis parameter s independently measured from the past magnetization history. By the backward Euler method with automatic modification, the transient analysis of this initial value problem is carried out. The characteristic values of the state transition matrix are calculated in each calculation step of Euler method in order to visualize this chaotic system. As a result, it is clarified that the chaotic behavior in the ferroresonant circuit is greatly concerned with the magnetic aftereffect of ferromagnetic materials.
Visualization of 1/f Fluctuation Characteristic in Energy Exchanging Processes
Masaaki Teranishi,Yoshifuru Saito
PDF   Abstract
Frequency analysis of the natural phenomena more or less exhibits a time fluctuation. Precise analysis of this fluctuation leads to the famous “1/f fluctuation” characteristic that gives mental as well as psychological relaxation effects to human. In the present paper, we focus on this “1/f fluctuation” characteristic observed in natural phenomena, in particular irreversible energy exchanging processes. As a result, it is found that a phase transition phenomenon such as a state changing to liquid from a solid accompanying irreversible energy exchanging process may exhibit “1/f fluctuation” characteristic. Thus it is revealed that any of the nonlinear phenomena accompanying irreversible energy exchanging processes may exhibit the 1/f fluctuation characteristic.
Shape Optimization of High Frequency Current Carrying Conductor by Skin Effect Visualization
Kohei Kuroda,Yoshifuru Saito
PDF   Abstract
High frequency operation of all conductors used in electrical/electronic devices causes the skin effect in the current carrying conductors. In particular, employing high frequency system bus in modern high speed computer leads to the serious skin effect, which is one of the causes of thermal loss. In the present paper, we try to visualize the skin effect in various frequencies when flowing high frequency current in the conductors with various cross sectional shapes. Referring to the visualization of skin effect, we try to searching for the optimal cross sectional shape of conductor distributing the currents uniformly. This means that the conductor having optimal cross section is capable of flowing high current without high thermal cupper loss. To visualize the current distribution, i.e., skin effect, it is essential to solve one kind of Helmholtz equations. We employ a semi-analytical method which reduces the partial differential equation into a set of equivalent electric circuits. Evaluation of each of the branch currents of the equivalent electric circuits visualizes the current distribution reflecting the skin effect.
Extraction of Magnetization characteristic From Visualized Magnetic Domain Images by Bitter Method
Takashi Sunaga,Masaaki Teranishi,Yoshihuru Saito
PDF   Abstract
The Bitter method is most commonly observing way of the magnetic domains even though it is limited to the surface observation of specimen. To observe the magnetic domains by Bitter method, magnetic liquid is put on the target magnetic material after electrical field polishing process. Applying magnetic field to this magnetic material covered by magnetic fluid makes it possible to observe the magnetic domain dynamics by a microscope. We have previously reported that local magnetization characteristics could be obtained from the visualized magnetic domain dynamics. Final purpose of our research on visualized magnetic domain dynamics is to work out a fully automatic quality control system for the thin magnetic materials by visualizing the magnetic domain dynamics. In the present paper, we try to extract the magnetic domain locations exhibiting 1/f fluctuated frequency movement from the dynamic magnetic domains because it may be considered one of the causes of magnetic noise as well as chaotic behaviors.
Visualization of Displacement Currents Flowing in the Capacitors
Kenji Hoshino,Yoshifuru Saitou
PDF   Abstract
One of the most important elements composing the electric circuits is the capacitors storing the electric energy in terms of electrical fields. Even though the capacitors are composed of the non-electrical conducting medium so called dielectric materials, the most distinguished electrical scientist Maxwell discovered that alternating current is possible to flow the capacitors. This leads to find the displacement current and to predict the electromagnetic wave propagation. As is well known, this electromagnetic wave makes it possible to commutate wireless electrical signal so that it may be regarded one of the major discoveries to construct the current modern high technology human world. In this paper, we try to visualize the aspect of displacement current distribution between the two electrodes of capacitor in order to optimize the electrode shape of capacitors based on the first order finite elements along with the equivalent electrical circuits.
Characteristic Extraction of Dynamic Image by Fourier Cosinusoidal Transform
Xiang Gao,Toru Kosugiyama,Yoshifuru Saito
PDF   Abstract
This paper concerns with a methodology of geometrical characteristic extraction from visualized dynamic image. At first, we briefly describe the color Eigen pattern method, which has been proposed by us to cognize the static images realizing the fully automatic security and product inspection systems. Since this color Eigen pattern method is based on the color information of distinct target image, then it is possible to cognize the target having the same color information. On the other side, our color Eigen pattern method could not distinguish the different targets having the same color information. To overcome this difficulty, we propose here a geometrical Eigen pattern method based on the Fourier Cosinusoidal transform. As a result, it is revealed that fairly good cognition may be promised by our geometrical Eigen pattern method at the initial test stage.
A study on Estimation of the Pollution Loads by Unit Value Method
- A case of Iruma River Basin in the Ara River System -

Yuta Simizu,Koji Kodera
PDF   Abstract
Recently, the river environment improved rapidly in the city region, spreading of the sewerage maintenance advances. On other side, the nitrogen pollution with the outflow water becomes a problem in the suburban area. For example, it originates from fertilizer, the livestock industrial waste, etc. Therefore, we build generic model to estimate for the amount of nitrogen exhaust load. This model based on the 1/10 land use data of digital national land information, to clear up characteristic of pollution for each branches by analyzing the domestic wastewater treatment rate and the amount of the farmland manure. In conclusion, some rivers which have urban growth rate are high, shows a successful performance.
Class-Attendance Control System by IC-tag in Distance Education
Norimichi Ishida
PDF   Abstract
The Distance education, or distance learning, is a field of education that focuses on the padagogy technology. In this paper, we figure out IC-chip is effective functional capability for control of entering and leaving class. We need to know at class situation of distance site from teach request that want to communicate to students in real time (synchriniusly). We made class-attendance control system with the HICA-systrm suppose prompt to early on came to class.
Sakai report
Yuji Tokiwa
PDF   Abstract
We recognized continuous enhancement of IT-based learning environment introduced on Sep., 2006 and have done the survey about Sakai which was open source collaborative learning environment mainly developed IT-leading universities in USA by both attending Sakai Conference and information on the Internet. Sakai is very informative in terms that Sakai can apply our learning environment to figure out the Sakai featuring the state-of-the-art technologies and development method. In addition to that, Sakai community is also useful to obtain the information about the IT-based pedagogical method from leading universities ahead of Japanese universities.