Recently, research on a conveyance system by magnetic levitation of steel plates has been active. Since the design of its control system is generally carried out for a linearized model, it is difficult to secure satisfactory robustness in the control system. This is because nonlinearity (which is ignored in modeling) and several disturbances exist in reality. In addition, for an actual steel plate conveyance process it will be necessary to develop a control system that takes into consideration various parameter errors, such as nonuniformity of the plate thickness and the associated weight variation. In this paper, we examine the achievement of robustness in the control system using μ-synthesis. Uncertainties in the noncontact electromagnetic support system of steel plates are considered.

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Thus far, we have reported that it is possible to suppress elastic vibration of the steel plate in the vertical direction by aligning several permanent magnets parallel to the electromagnets that are installed for positioning the magnetically levitated steel plates in the horizontal direction. With the change in distance between the permanent magnet and the edge of the steel plate and the distance between permanent magnets, the attractive force applied to the steel plate by the permanent magnets changes. Due to such uncertainties arising in modeling, the performance of steel-plate positioning by the electromagnet deteriorates. In this study, we design a robust horizontal positioning control system for magnetic levitation of a steel plate using μ-synthesis in which the above uncertainties are taken into consideration.

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Characteristics of two time constants in a control system of a magnetic suspension and balance system (MSBS) are investigated in detail in this study. Influences of the time constants on control performance are also investigated and a performance index to optimize the time constants is proposed. The performance index includes deviation of step response and influence of disturbance, then the time constants can be optimized in consideration of the system stability and the disturbance response. Furthermore, a weight coefficient in the performance index can be used as a criterion between the stability performance and the disturbance rejection performance.

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The flux-weakening control is very effective to attain a high-speed rotation of an interior permanent magnet synchronous motor (IPMSM). To increase robustness of the flux-weakening control, we propose a new control method of both a d-axis current and a q-axis current by using a voltage feedback with the sliding mode control. The proposed control archives a high speed rotation against an error and a change of IPMSM parameters. Through a simulation we show an effectiveness of the proposed control method. In result, the parameter adjustment with a load examination machine is not needed.

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A spring-type actuator i s presented, which has both restoring force and actuator characteristics. The fer ri te particle layer is made of silicon paste and ferrite particles, in which fer ri te particles are pasted by the si licon paste. The ferrite particle layer is pasted to the coi l of the spr ing, and so the layers are constructed inside of the coil spring with small gaps. When magnetic fields apply to the coil spring, att ractive forces apply between ferrite layers, and so the spring deforms due to the magnetic fie ld. In the present article, a method of production of the actuator is presented, and its control method i s also developed. To validate the actuator, a step response and frequency response has been discussed.

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In this research, the jump robot that used an electromagnetic actuator was developed. It is thought that using the spring to compensate for the deadweight of the robot that should correspond to various situations has the problem though the spring has been used to compensate for the deadweight of the jump robot so far. Then, a simple structural linear actuator that accumulated a permanent magnet and the permanent-electromagnet was developed, and it used it to compensate for the deadweight of the jump robot instead of the spring in this research. The jump experiment of three degree of freedom jump robot that installed an electromagnetic actuator was done.

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This article reports a study on the development of a new ER hydraulic draft gear as a relief buffer for the purpose of lower the coupler force acting between the failed and the relief bullet train set. A prototype buffer consists of a hydraulic cylinder, an ER bypass slit valve, and a PID feedback controller was developed. The damping force is developed in the ER fluid both through the bypass slit and at the piston-cylinder gap. First, theoretical analysis of the fluid characteristics of the buffer is conducted. Next, the primary functions and performance of the buffer as an active buffer are investigated experimentally. Theoretical analysis and experimental results show that the coupler force of the railway vehicle can be controlled effectively by using the proposed electrorheological bypass damper.

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The traveling wave micropump with a thin flow layer is suitable for particle separation and quantification without valves, heat and strong electric field. We have proposed a traveling wave micropump driven by the traveling wave, and demonstrated high efficiency. In this paper, we fabricated a traveling wave micropump composed of flexible microchannel wall made of Polydimethylsiloxane (PDMS) with piezoelectric thin-film unimorph actuators. The piezoelectric thin films were deposited directly on cantilever-shaped stainless steel (SUS) substrates using rfagnetron sputtering technique. The active motion of the particles in the fluid was confirmed by the actuation of the microchannel wall by the piezoelectric actuators.

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Fe-Si alloy system was investigated on the magnetoresistance (MR) effects in a temperature range between 77K-RT and in high fields up to 30 T. The samples were prepared by sputtering Fe on Si(100) surface and variously annealed up to β-FeSi_2 are obtained. The MR effects were found small less than several %, negative at RT and positive at T=77 K for Fe-rich samples. For a sample at the stoichiometric β-Fe-Si_2, we found positive MR very large more than 40% at RT in B=30T. The physical mechanism of the large MR is given rise by the carrier freeze-out effect.

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For the purpose of analyzing the magnetic single-component development process of electrophotography, we measured 3D-figures and charge density of toner images on a photoreceptor drum and an OHP sheet with a co-focal laser focus displacement sensor and a Faraday cage. The results were as follows: (1) In a toner image on the photoreceptor, it was confirmed that mountain-like chain structures were formed parallel with development direction. (2) In a toner solid image, charge density in the center area is lager than that in the edge and volume density in the edge is lager than that in the center area.

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This report describes the active control systems of floor impact noise. The systems are comprised of actively controlled modular panels of light weight, which wholly cover the surface of concrete slab structure in the ceiling, and in each of which the mechanical vibration is controlled independently with moving coil actuators. In this report, first, vibration control system is presented. Second, acoustic evaluation of active insulation panel is presented. In the latter evaluation lower performance was acknowledged than expected from the former measurement, due to less computing precision of micro-computer controller.

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This paper describes the micro-computer feedback contol system for active modular panel systems in order to insulate floor impact noise. We develop a micro-computer system equipped with Renesas SH3-DSP processesor. The micro-computer system is composed of two boards: CPU board and analog I/O board. Renesas SH3-DSP processor has a function of digital signal processor which performs high-speed calculation of fixed-point number. Because we use Matlab software in order to design robust feedback controllers, each entry of controller matrices is double-precision floating-point number. Rounded errors occur when these matrices are installed into the micro-computer system. First we show the construction of the developed micro-computer system and the block diagrams of the robust feedback system. Next we conduct the control experiments of with twelve panels and discuss about the effects of rounded errors.

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The purpose of this study is to reduce a transmission noise of floor structureby the active noise isolation unit which constructed from thin board and piezoelectric viblator. The piezoelectric vibrator is attached to the thin board by the center connection bolt. Through the experiments, the effects of material of isolation control board on isolation characteristics were investigated. The experimental results show that isolation loss at input frequency from 200Hz to 700Hz is obtained about 50dB by using thin and lightweight boaed. In addition, by using the insulator material pasted to the control board, the isolation loss could be increased.

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This paper proposes an active control system to reduce the sound transmission through walls without analysis of their characteristics of vibration. The system consists of the plural of control modules installed target walls which have piezo ceramic loudspeakers as a secondary source. Controling sound pressure near the wall and modules's structure make it possible that each circuit has single input and single output. As a result of the experiment of the verification that assumed application to the railway vehicle, we could recognize that the sound radiation power from the target wall was reduced over 4dB.

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In 3-dimensional sound field, it is difficult to control noise in whole area. Instead of whole area control, the controlled area can be followed to people in that field by new approach proposed in this paper. In the proposed algorithm, FTF algorithm that has fast converging property is introduced to a direct adaptive algorithm which does not need an error path characteristic. A numerical simulation is carried out with a sound field that the error microhpne moves during control. Experiments are also carried out under several conditions. From the results of the simulations and the experiments, the effectiveness of the proposed algorithm is shown.

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Two-dimensional microphone array is used for measurements of sound fields, and the measured results are applied tovarious purposes, for example, analyses of sound fields ,realization of a ultra-directional receiver, and so on. Such an array has many microphones and some structures to support microphones, so that it is supposed that the bodies of the microphones or the structures of the array would disturb the measured sound field. Some experimental results have been already shown by authors that there are some effects of the array structure to the sound field. In this study, an analytical method to investigate the effects of the array structure is developed, and some ideas to reduce the effects are discussed.

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This paper describes the identification and statistical evaluation of impact forces caused by coins falling to a storage box of a coin counter. Because of the difficulty of accurate calculation for the excitation points and magnitude of the impact forces, the virtual excitation points are assumed. The experiments about the different number and kind of coins are carried out and then the virtual forces are estimated in each experimental condition. It is confirmed that the characteristics of frequency spectra of the virtual forces depends on the number and kind of coins and has reproducibility. Next, the input power which has Gaussian probability distribution is assumed as the stochastic impact force's model. The estimated frequency responses of acceleration of the storage box coincided well with the measured values.

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The noise of narrow-gauge vehicles is composed of rolling noise, electric apparatus noise and driving system noise. In recent years, the total noise tends to increase with speed up. The noises radiated from electric apparatus and the driving system tend to decrease, however, the rolling noise tends to increase relatively. This paper reports the characteristics of sound radiation obtained from BEM analysis and bench experiments of wheels with different web shapes, or webs of corrugated and straight standard types, which are used for narrow-gauge railway vehicles. We found that the noise of NA-type corrugated wheel is the highest value in four kinds of wheels which we experimented on,and the typical frequency of the main modes is 1257Hz.

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Concerning the rolling noise of wheel/rail coupling system, first the power spectrum of contact force between wheel and rail is calculated by random vibration analysis and besides the vibration responses of rail and wheel is obtained by use of Timoshenko beam theory for rail in addition to FEM model for wheel .Then, using those vibration responses as the boundary conditions of acoustic analysis of BEM, the acoustic powers radiated from wheel and rail are obtained and the rations of respective power to total power are estimated for three kinds of confgurations of wheel, that is, straight web wheel, corrugated web wheel with six circumferential wave number and TGV-type wheel.Concerning the rolling noise of wheel/rail coupling system, first the power spectrum of contact force between wheel and rail is calculated by random vibration analysis and besides the vibration responses of rail and wheel is obtained by use of Timoshenko beam theory for rail in addition to FEM model for wheel .Then, using those vibration responses as the boundary conditions of acoustic analysis of BEM, the acoustic powers radiated from wheel and rail are obtained and the rations of respective power to total power are estimated for three kinds of confgurations of wheel, that is, straight web wheel, corrugated web wheel with six circumferential wave number and TGV-type wheel.

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Noticing the noise reduction effects of the drainage asphalt pavement, the method of estimation of radiation characteristics of automobile tire/road noises and the road design concept of reducing such noises are examined. By using FEM, the tire vibration responses depending on the grain size of road texture are obtained and regarding those responses and the normal acoustic impedance of the finite area simulating road surface as the boundary conditions for acoustic analysis by BEM, the sound pressures radiated from the tire on the both of the dense and porous asphalt pavements are calculated. As a result, it is verified that in the drainage asphalt pavement, the tire/road noise is more reduced than in the dense pavement by the suppression of horn effect in addition to the excess attenuation due to sound absorbing effect of porous asphalt.

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Payload and equipment mounted on honeycomb panels of artificial satellite are exposed to intense random vibro-acoustic environment during launch. In order to describe how payload components vibrate by the sound excitation along with certain margin regarding uncertainties in the early stage of design, this paper deals with the method to predict the random acoustic vibration of equipment mounted on honeycomb panel. This makes the prediction approach simple and possible to analysis the each panel instead of mounted on satellite. We found that it doesn't need to test and calculate the full configuration, as the conclusion, the predicton method may be simplified to treat the panel alone. And more, we can propose the simplified method by the impedance coupling approach based on SEA to predict random acoustic vibration response with mounted equipments on honeycomb panel, which is the common satellite. It can be given good results.

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This research aims at the development of a method for optimal structural countermeasure concerning structure-borne noise radiated from machinery and structures. A new process for deriving countermeasures using Statistical Energy Analysis is proposed in this paper. This process is composed of four steps, 1) construction of SEA model, 2) identification of power input during operation and of power transfer paths, 3) extraction of loss factors for countermeasure and 4) structural design for realization of loss factor changes. The process is applied to countermeasure for structure-borne noise radiated from a laser beam printer. As a result, it is shown that the process works well to reduce the sound pressure levels.

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This paper describes the structural optimization of a rectangular thin plate by adding rectangular dimple for noise reduction. Aiming to reduce sound power at higher natural frequencies, the distance between a nodal line and a driving point is selected as an objective function, and dimentions and position of the additional rectangular dimple are set as design variables. The radiation sound power from the optimum plate obtained with the Sequential Quadratic Programming Method remarkably decreases.

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Noise reduction is becoming more important in design process of automobile, aircraft, electric appliance and others from the viewpoints of environment problem and improvement of product value. Embossing processing is proposed as a noise reduction technique for panel structures and the authors studied about optimization of placement and dimension of embossing. Embossing is a good technique to improve stiffness of panel structures and reduce sound power level. However, it is not effective in reducing peak levels of sound pressure level at resonance frequencies because of little enhancement of damping. In this paper, the combination of embossing and PZT shunt circuit is proposed as a more effective technique to reduce noise radiated from panel structures.

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The purpose of this research is to reduce the floor impulse noise due to heavy-weight impact source. The supporting leg with magnetic damper is designed to isolate the impact force from the double floor by magnetic surfacing. In the experiment, the performance of supporting leg with magnetic damper is evaluated from the static load, the impact load, and the floor impulse noise. The experimental results show that the supporting leg with magnetic damper is effective to reduce the floor impulse noise due to heavy-weight impact source.

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In this paper we design a gain-scheduled (GS) H∞ controller of a semi-active seismic isolation system using a large-scale 40 kN-class magneto-rheological fluid (MR) damper for a four-degree-of-freedom structure. By introducing a fictitious damper model we can transform the bilinear model into a linear parameter varying (LPV) model for which designing of a GS controller based on linear matrix inequalities (LMIs) is available. For verification of the control performance we carry out simulations and experiments for some kind of earthquakes using the 40 kN-class MR damper. In comparison with the skyhook damping control or a passive damper it is verified that the proposed method has good performance.

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This paper proposes two design methods of piezoelectric dampers. One is based on the fixed-point theory by which the parameters of piezoelectric dampers that suppress the accelerance are optimized. The other is based on the H∞ static output feedback control theory. Since minimizing H∞ norm of the system implies suppressing the magnitude of the frequency response of the system, this method is applied to the design of piezoelectric dampers. The effectiveness of the piezoelectric damper designed by the H∞ control theory method control theory is examined compared with that designed by the fixed-point theory.

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This paper proposes a vibration control system using a connecting dynamic absorber and damper for plural vibration systems that have same natural frequency. In this study, the vibration control system is designed from the view of feedback control. The controller, i.e. design parameters of the dynamic absorber and the connecting damper, is designed by static output feedback H∞ control theory. Finally, numerical simulations show the advantages of the proposed system.

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Since a steel frame system three-story house tends to resonate with traffic vibration transmitted in the foundation, each maker company has coped with it by installing TMD (Tuned Mass Damper). However, there is a problem tuning of TMD shifts from the optimal state because the characteristic of a building changes with degradation by many years past etc. There, development of the vibration suppression equipment which can respond to a broad frequency band is expected to be able to respond, even if the characteristic of a building changes to some extent. Then, a basic performance of the impact mass dumper is estimated by the analysis in this research, and the possibility as the traffic Vibration suppression device for the detached house is examined.

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In order to achieve more perfect vibration-free environment in base-isolated semiconductor factories, a smart structure was tested for comprehensive active microvibration control in a base-isolated 2-story steel frame building model of a 5×3×4H m external size and a 6,900 kg total mass which was supported by four multistage rubber bearings. In the building model, 20 piezoelectric actuators were attached to the columns and the beams, and eight actuator units consisting of two piezoelectric actuators each were installed between the bottom of the superstructure and the foundation. The controller was designed by a model-matching method. The tests showed that the smart structure could effectively control three-dimensional both microvibrations generated by equipments and people in the buildings and excited by external disturbances such as ambient ground vibrations and winds.

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Switching vibration control between dynamic absorber and active control has been proposed for the dual structure vibration device on the basis of the kinetic energy as the threshold. For the active control with a fixed feedback gain, the threshold should be set conservative and the effect of the active control was not enough. Therefore, a variable feedback gain is introduced, which is assumed the kinetic energy as an indicator. It is expected that the actuator moves in a mobile range as possible and the performance will be better than the conventional switching control. In this paper, the effective variable feedback and switching are considered by experimental results.

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Dynamic Absorber has different amplitude-rate on the anti-resonance frequency by damping coefficients. A semi-active control was proposed, which switched the damping coefficient by frequency elements of the vibration structure's displacement. Band pass filter (BPF) was introduced to divide the frequency band on whether the amplitude-rate was smaller or not. However, there are another possibility to divide the frequency band by BPF, acceleration of earthquake, displacement of earthquake, structure's velocity and so on. In this paper, the effective switching index is considered by comparing with those candidates and experiments.

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This paper presents a control method for multi-degree of freedom system with an AMD (active mass damper). A sliding mode controller is applied to vibration control for a nonlinear model of five degree of freedom with an AMD. The output feedback control procedure has the switching hyperplane with dynamics by a liner operator. Therefore, the frequency shaping controller is introduced not only to suppress the chattering and the spillover, but also reduce the sensitivity of the motion of AMD to disturbance in extremely low frequency region. The effectiveness of the controller is demonstrated by the numerical results and the experimental ones.

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A dynamic damper using Mn-Cu alloy is proposed to reduce vertical vibrations of long-span footbridges. Free vibration tests using small cantilever models with Mn-Cu alloy plates and vibration response analyses of the footbridge with the dynamic damper are carried out to investigate damping properties of the Mn-Cu alloy and evaluate vibration control performances of the dynamic damper for the footbridge. From the experimental and analytical results, it is confirmed that the responses of the footbridge for the walking vibrations and the seismic waves can be reduced sufficiently by applying the dynamic damper using Mn-Cu alloy.

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The dynamical seismic design of a structure is often carried out by using response spectra as functions of damping ratio and natural period of the structure. For an actively-controlled structure, however, the response spectrum analysis is hardly executed. A newly response spectrum is proposed to evaluate the structural response of actively-controlled structure subjected to earthquake. This paper adopts a linear single-degree-of-freedom structure with active mass damper (AMD) system. An earthquake is modeled as Gaussian random process with Kanai-Tajimi spectrum. The control design is executed by linear quadratic Gaussian control strategy. Finally, the response factor is given by combination of the obtained statistical response values and random vibration theory. Analytical results are compared with numerical simulations.

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This study has been examined the 3-dimensional measurement method for dynamic displacement of real scale test model on shake table tests. This system can measure 3-dimensional dynamic behavior of test model without any contact by applying an optical motion capture technique and image processing technique. The system therefore is the most suitable measurement system for an evaluation of complex 3-dimensional behavior of test model. This paper describes the dynamic measurement accuracy, the effectiveness of the proposed system from the results of shake table tests using the 1/5 scale Five-storied Pagoda model.

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The equipment and the piping systems of the nuclear building with the natural frequency at high frequency band of more than 20Hz is basically considered the rigid body and the static seismic design which uses floor response spectrum of support structure is implemented. Therefore it is conservative design for including major safety margin. In background of that, the establishment of the more rational evaluation methods is very important, now. And that study focused attention on the method based on energy balance the vibration characteristics of mechanical structure, and studied from the experiment and the analysis point of view.

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In Japan, the seismic design methods for structures are developed in the civil and architectural fields. And these seismic design technologies have also been brought to mechanical structures such as piping facilities and boiler structures, etc.. But, for the geometric time varying structure of which geometric configuration is dependent on time such as cranes, the kinetic and the dynamic characteristics of such structures are not fully considered in the seismic response analyses. In this paper, we try the modeling of the geometric time varying structure systems by means of the method of multibody dynamics.And we examine the effect of the geometric time varying system on the seismic response. The beam elements formulated by the absolute nodal coordinate are used to model the structure that has large displacement motion of the base of the structure. The crane structure for the building construction is modeled in the numerical example.

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This study treats the dynamic stability of mechanical systems subjected to multi-directional excitations, such as dynamic buckling behavior, etc . A steel cylindrical pier is treated and modeled analytically as a thin cylindrical structure with an attached mass on its tip. The analysis is carried out by numerical simulations, where the horizontal and the vertical seismic loads are applied simultaneously. The effects of the horizontal and vertical input frequencies on the dynamic stability are studied. It is known that the seismic responses of the thin cylindrical shell structure tend to increase due to the coupling effects between the horizontal and vertical excitations, and that flattening phenomena make the cylindrical shell structures more unstable.

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This study was to examine the optimum height of chair for standing up operation and to inspect the shake of the center of sole pressure and the characteristics of EMG during the standing movement. Standing movements performed at the height of seating posture (hip, knee and ankle joint were 90 degree), and at he height of ±2%, ±4% and ±6% of the seating posture. The center of sole pressure was measured by a force-plate and the EMG's of the muscles of lower limb were measured. The shake of the center of sole pressure was larger at higher sitting height, on the other hand, the EMG activity was larger at lower sitting height. The large shake of the center of sole pressure means the large transfer of center of Gravity, consequently the posture of standing up operation from high chair decreased the load of lower limbs.

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In order to clarify the difference between a welfare-chair and usual-chair, the evaluation of to easiness seat chair and the measurement of the pressure distribution in seat for long-term were performed. Twenty young adult male subjects participated in this study, and kept sitting on each chair for thirty minutes. The measurement of easiness to seat was evaluated by SD scale that is divided to five levels by means of adjective. The distribution of seating pressure was measured by Force Sensitive Application Ver.3.1(Takano Co Ltd.) Easiness to seat and the distribution of seating pressure were confirmed different by the condition of seating position and the kind of seating chair.

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The measurement of the grasping space formed by hand have been measured. The grasping space of mother finger and index finger inclined from 15 by 20 degrees, three grasing spaces of the palm -middle finger, the palm -ringe finger , and the palm -little finger were almost constant. Moreover, the holding diameter can be approximated as the first approximation in the oval. In addition, as aproximated as a clinder, the obtained grasping space diameter neraly same as optimal grasping diameter evaluated sensory test.

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In recent years, buildings have become taller so the horizontal vibration of the cage becomes a very important factor for evaluating ride comfort. As is discussed in ISO 8041, vibration sensibility of human body depends on its frequency characteristics. And continuativeness of vibration is also important. The objectives of this study are to clarify the frequency characteristics of human body vibration sensibility in the horizontal vibration, and also to clarify a relationship between the discontinuous vibrations and ride comfort. Through evaluation experiments, it is verified that the result shows a similar frequency characteristic to ISO 8041.

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To design a comfortable sleep environment, the system that presumed the sleep satisfaction rating subjectively evaluated from the sleep variable requested by the physiology index was constructed. The subjectivity evaluation was done to OSA sleep investigation vote, and the sleep variable was requested from the physiology data of the brain wave, the heart beat, and the ocular motility, Five sleep factors with OSA sleep investigation vote and the correlations with the sleep variable were clarified, and the conversion type that presumed the satisfaction rating of sleep from the amount of the physiology was clarified.

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Domestic accidents such as a fall have increased with aging. To detect the accident, the monitoring system that discriminates their motion of daily life has been required. Though EMG is generally used as a physiological index of discrimination, it has problems such as noise from life environment and worrying about affixing the electrode. Therefore, we proposed to use the muscle shape change of leg with motion. Amount of muscular deformation is measured by using strain-gauge-band wound around cruris of legs. As a result, walking, going up/down stairs, standing/sitting, turning were able to be distinguished. And, we proved that the physical change of muscle is effective index.

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To optimize the experimental method for sensory evaluation of the car seat, the sensory test and the measurement of body pressure distribution is carried out by the experimental designing methods. The question of the comprehensive evaluation concerning the feeling of sitting on the car seat and the region of body was prepared for sensory test the subjective and the objective for sensory test. The feeling of sitting is evaluated with the question item of the subjective and the objective respectively. The relation among the comprehensive evaluation, other question items, and the body pressure distribution was analyzed, and correlation between sensory score and pressure distribution is recognized.

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Steel railway bridges characteristically tend to generate high-level structure-borne noise. The authors have developed a method to predict structure-borne noise based on the analysis of flexural vibration of plate, however it possesses a drawback that it is difficult to calculate directly the exciting force generated by contact of wheels with rail. On the other hand, recently new methods are developed to analyze dynamic interaction between rail and wheels by modeling the rail as an Euler's beam supported discretely at constant interval, and assuming sinusoidal surface irregularity of rail. So we tried to apply this method to analysis of rail vibration response on steel railway bridge and examine to combine this method with above-mentioned method for prediction of structure-borne noise.

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At present, the design that utilized human sensitivity is demanded. It is necessary for exploiting human sensitivity to measure it. The paired comparison is one of the sensory evaluation methods, especially Scheffe's paired comparison evaluates the human sensitivity and adds a relative score to the samples that have a little differences. However, the conventional Schffe's paired comparison can separate the main effects, differences among individuals, order effects and combination effects. If there will be the other factors that have an effect on the samples' evaluation, the effects will be neglected. The new sensory evaluation method that is proposed in this paper enables to separate main effects, differences among individuals, combination effects, and another effects. In this paper, we propose this new method and apply it to the loud speakers' psycho-acoustic evaluation.

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A survey was conducted to classify IT device users in order to identify truly useful IT devices: In the 1st stage, comments of examinees on a several kinds of IT device were collected, describing reasons why use or not use the IT devices, to obtain a numerical ratio of the interface-referring comments to the personal preference comments. In the 2nd stage, examinees were divided into 3 groups, i.e. a group of high ratio, low ratio and intermediate ratio. And in the final stage, various attributes such as age, gender, cognitive character etc. of each group were compared to identify the attributes of significant difference.

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