We developed a novel nano-imprinting machine to transfer pattern on a side-surface of a substrate, unlike a conventional nano-imprinting machine which transfers pattern on an upper-surface of a substrate. For a micro-spectroscope, a diffraction grating was fabricated on an end face of a light guide plate using the developed imprinting machine. The pressure distribution and pattern resolution were evaluated. On the whole end-face with 1mm×20mm area, uniform pressure distribution was obtained. A 400nm-periodic-structure was also fabricated well on the end face. A silicon mold for the diffraction grating with the 10μm period and 100nm height was fabricated using photo-lithography and dry-etching techniques. By pressing the silicon mold, the diffraction grating with the 10μm period and 100nm height was fabricated well on the end face of the light guide plate. The optical characteristics were measured. The measured diffraction angles agreed well with the calculated values. The maximum error of the diffraction angle was 0.22% between-3 and 6th diffraction orders.

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The conventional escalator keeps the operation speed, when passengers move at any traveling position. If the speed at the inclined middle part is faster than the riding and leaving position, such a system can not only achieve short traveling time, but can also offer safety ride to elderly and disabled person. Therefore, the concept to change the speed partially in the traveling range has a great advantage to the passenger. The idea for speed change mechanism has already been established to a moving walk, which is horizontal one dimensional motion. However there is no actual two dimensional system with the speed change mechanism, due to its complex configuration. This paper shows a new speed change mechanism for an escalator, which is a typical moving mechanism for the two dimensional service, and shows a design method of the mechanism to fill the acceleration specification. The proposed mechanism can be achieved by a simplified link and cam mechanism to realize a smooth speed change between the inclined and horizontal zone. The simplified design method based on difference equation can evaluate the transient motion of the escalator step, which is strongly affected by the geometric constraints. The simulation result and an experiment with a 5m-tall prototype show its design validation for the smooth ride comfort even in the area of the speed change.

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In structural designs considering thermal loading, to control thermal stress and minimize decreases in material strength at high temperatures, it is important to maximize the thermal diffusivity of structures, in addition to the usual maximization of stiffness that optimal designs achieve. This paper presents a new level set-based topology optimization method for thermal problems with generic heat transfer boundaries in a fixed design domain that includes design-dependent effects, using level set boundary expressions and the Finite Element Method. First, a topology optimization method using a level set model incorporating fictitious interface energy is briefly discussed. Next, an optimization problem is formulated using the concept of total potential energy to address the design of mechanical structures that aim to minimize the mean temperature of the structure under thermal loading. An optimization algorithm that uses the Finite Element Method when solving the equilibrium equation and updating the level set function is then constructed. Finally, several numerical examples are provided to confirm the utility of the proposed optimization method.

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A design method based on interval estimation for determining the appropriate number of samples for seismic analysis using the Monte Carlo method was developed. The Monte Carlo method requires an appropriate number of samples to produce valid results. However, an increased number of samples might increase in computing cost. It is therefore desirable to determine a reasonable number to give the required accuracy. The developed method with use of interval estimation can determine the relationship between number of samples and the error for mean and standard deviation, which are the dominant parameters that define a probability distribution of seismic responses. Accordingly, the number of samples needed to produce the results with required accuracy can be determined from the relationship. The results of the developed method were compared with those of the Monte Carlo method for elastic and inelastic single-degrees-of-freedom systems. It is demonstrated that the developed method can determine the reasonable number of samples needed to produce the mean and standard deviation of seismic responses with the required accuracy.

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For the past several years, large scale earthquakes happened. A lot of industrial facilities were damaged. For example, a nuclear power plant was stopped in The Niigataken Chuetsu-oki Earthquake (2007). These earthquakes have larger acceleration level than the seismic design level. Therefore, the earthquake proof measures are required. There are many dampers as the energy dissipating devece. For example, oil damper, visco-elastic damper, magnetic damper, friction damper, elast-plastic damper, and so on. The friction damper and elast-plastic damper are utilized for the large scale earthquake. This paper deals with the response reduction effect by elast-plastic behavior. Elast-plastic behavior is expected to absorb the seismic energy. In this paper, bi-linear model and R-O model are focused as the elast-plastic model. At first, the comparison of the characteristics of these models is taken place. Next, the response spectrum for seismic design is proposed.

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In this paper, authors propose a vibration suppression device that utilizes inertia mass by fluid in order to obtain effects of vibration cut-off or suppression. The device consists of a cylinder, a piston and a by-pass pipe. The inertia mass is generated by a movement of the fluid in the by-pass pipe during excitation, and magnified by not only ratio of inner diameter between the cylinder and the by-pass pipe, and also a weight ratio of the fluid. The test device was manufactured, and resisting force characteristics are measured in cases of water, turbine oil, and MR fluid filled in the by-pass pipe, respectively. It is clarified from the results that variable inertia mass can be derived in case of the MR fluid when magnetic flux is applied. In order to confirm the effect of vibration suppression, experiments of frequency response and seismic response of one degree of freedom system with the test device are carried out by using a shaking table. Acceleration and displacement can be isolated from input excitation, and resonance frequency can be shifted toward low frequency by the inertia mass. Vibration suppressions of the device are confirmed theoretically and experimentally.

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The concrete placing of dam is carried out by a large-scale crane which a skill operator actuates based on the long experience. Automatic driving of the crane is recently expected for shortening the cycle time for carriage and placing of the concrete. The load needs to be rolled up and down while the trolley runs. Then, because the length of the hanging load rope changes with time and the crane system is time varying system, the conventional linear control theory is not applicable for the antisway control. In this study, an open-loop control is proposed by introducing nonlinear time scale, which is chosen so that the equivalent natural frequency is not changed regardless of the variation of the length of the load rope. The acceleration pattern is designed by introducing the nonlinear time scale and the residual vibration after the acceleration (or deceleration) can be avoided regardless of the velocity of the rolling-up (or down) of the hanging load rope. Finally, the validity of the proposed control technique is confirmed by numerical simulations.

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This paper presents a reaction force compensation methodology of shaking tables for earthquake simulators. When a shaking-table of an earthquake simulator is driven for the seismic experiment of a specimen, its motion is affected by a reaction force caused by the specimen on the table. The compensation methodology is designed by using the DMM (Dual Model Matching) based on the characteristic transfer function. We adjusted feedforward control and feedback control such that the influence of the reaction force is reduced and frequency response of the shaking table is improved especially in the high frequencies. The effectiveness of the proposed technique is also verified by experiments.

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This paper presents a response evaluator which evaluates the response of the system and decides the control input to the system. The characteristics of the response evaluator is designed with the source region and ground motion of earthquake. It is applied to a base isolated structure with a semiactive oil damper whose damping coefficient has large or small values. The response evaluator is designed by the multi-layered neural network which consists of the building responses and the peak ground velocity as input data and switching signal for damping coefficient as output data. Some earthquake records are divided into 8 regions by the epicenter, and the representative record of each region is normalized to 3 levels of its peak velocity which is 25, 50 and 75cm/s. The 8 response evaluators are designed for each earthquake region and the computer simulations are carried out. Absolute acceleration and relative displacement of each story are reduced when the response evaluator corresponding to the designed region is used, but the control performance is not so good used by the most of response evaluators designed at the other region. When the response evaluator is selected corresponding to the designed region and the appropriate criterion function is set, good control effect is obtained to the wide range of amplitude of earthquake.

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This paper presents a new sliding mode controller based on the integral sliding mode control (ISMC). It is shown that the original ISMC, which was proposed by Utkin et al., together with the so-called proportional reaching law tends to bring about windup phenomena under actuator saturation since the dynamics of the switching function is not asymptotically stable. In order to overcome this problem, the dynamics of the auxiliary variable used in ISMC is modified so that the dynamics of the switching function should be asymptotically stable in a certain region of the state space even during the actuator saturation. Thus, the proposed controller guarantees that the sliding mode can take place under the actuator saturation much sooner than the conventional ISMC. In addition, without the actuator saturation, the proposed controller can be seen as a kind of the proportional reaching law. Numerical simulation and experimental results demonstrate the effectiveness of the proposed controller.

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In this paper, we consider the position and attitude (six dof) tracking control of rigid body spacecraft by dynamic output feedback and proposed a new passivity based control method. To this end, the relative motion equation of the six dof rigid body spacecraft is first derived. Then, we design dynamic output feedback controller so that the closed loop system of the relative motion equation is asymptotically stabilized. By the proposed method, the spacecraft can track an arbitrary trajectory because the derived controller has no singular point. This is the excellent property compared with the conventional methods. Finally, effectiveness of the control methods is verified by numerical simulations.

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The precise in-situ measurement of wafer temperature has not been achieved in the semiconductor processes of 200[℃] or less such as photolithography and dry etching. The post exposure bake (PEB) sensitivity is well known as one of the main factors to critical dimension (CD) non-uniformity in photolithography. For that reason, we proposed an in-situ measurement and control method of wafer temperature based on micro area contact to a processing wafer using some micro sensors. The 1st report showed the effectiveness of the proposed method, in-situ measurement accuracy 0.1[℃] etc. from experimental results using a large model of the micro sensor. This paper shows the fabrication of 650×650×280[μm^3] sensor chip based on MEMS technology and its characteristics. The process flow of the fabrication consists of thermal insulation structure formulation using permanent photoresist, half cut dicing and polishing of Si substrate to 10[μm] or less in thickness, through-vias formulation into thermal insulation structure using Ag nano paste, and so on. The measurement accuracy of the sensor chip is 0.03[℃], and it is high enough as a resistance temperature detector. In addition, the mounting method of the micro sensor in a plate surface using the nanomembrane of 200[nm] in thickness is proposed for the purpose of its protection against cleaning of the plate surface at maintenance, suppression of particle generation from it, and so on. The proposed mounting method will be able to improve resistance to trouble without degradation of in-situ measurement accuracy.

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In order to reduce the adverse effect of disturbance, the exact dynamical model of disturbance must be contained in the closed loop system. However, in general, the control performance deteriorates because of disturbance when the dynamical model of disturbance is unknown. Studies on disturbance attenuation based on an observer with a function of estimating unmeasurable inputs have been developed in recent years. The aim of these studies is to synthesize the compensator which alleviates the bad influence of disturbance without disturbance model. In this paper, the regulation and servo control strategies based on disturbance attenuation are presented, and an application to the 1-mass system is given to show the effectiveness of the proposed methods.

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As a new countermeasure to the interior noise of the railway vehicle, a development for a noise control system with piezoelectric material has been advanced. This paper describes availability verification test about the system in the railway vehicle, which is considered to have a very hard situation for application of the active noise control system. For the test of the noise reduction effect in running vehicle, we manufactured the noise control system sets for a deck of the Shinkansen, and assessed the noise reduction effect in stationary test. A target frequency was determined based on the noise reduction effect and the characteristics of the interior noise of the deck. Numerical analysis was carried out about the noise change distribution in the deck at a target frequency when the noise control system applied on the outer-side gable wall. Furthermore, the noise control systems are actually installed on the outer-side gable wall in a deck of the Shinkansen vehicle, the interior noise of the deck suppressed maximum 4dB in control frequency range, and the result demonstrates the availability of the system to the railway vehicle.

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Human voices originate from the vibration of vocal folds in the larynx. In most previous studies on voice generation, a planar sound source was assumed for a laryngeal sound source and the effects of airflow in a larynx were neglected. However, without this airflow, vocal folds cannot oscillate. The airflow in a larynx is a key factor in the vocal fold vibration. Therefore, detailed study of this airflow is necessary to elucidate mechanisms of human phonation. In the present study, airflow just above the glottis was experimentally analyzed to clarify the phonation mechanism and seek better modeling of vocal folds. This experiment focused on direct measurement of the airflow velocity by means of a tiny hot-wire probe, direct measurement of subglottal pressure by means of a catheter pressure transducer, and simultaneous observation of vocal fold movement by means of a high-speed digital camera. During the closing phase of the glottis, the vocal folds constrict the airflow and the airflow velocity is at its highest. The subglottal pressure also becomes higher during the closing phase, however, the closing of the upper lips of the vocal folds is later than the moment the subglottal pressure is at its highest. The movement of the upper lips dose not synchronize with that of the lower lips. These are important because they provide crucial information to create better simulation models of the phonation mechanism.

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In recent years, higher combustion efficiency and lower emissions are required on engine development and therefore higher combustion control is necessary. To realize higher combustion control in reciprocating engine, cycle to cycle flow rate measurement is important. Especially it is a key factor to control HCCI combustion. Traditional laminar flow meter has a problem in responsibility. However, fast response differential pressure transducer allows cycle to cycle dynamical flow measurement. The availability of fast-response laminar flow meter on cycle-to-cycle flow rate measurement is shown in this paper.

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We have developed a unicycle robot that consists of a body, a disk driven by a dc-motor to stabilized its posture, and a wheel driven by another dc-motor to move the body forward. The robot has only two motors and there is no direct force to change the yaw direction of the robot. For changing the yaw direction, we use sinusoidal inputs for the disk and for the wheel. The present paper shows that an average substantial input for the yaw direction depends on the phase difference of the two sinusoidal inputs, and then proposes a control method for changing the yaw direction from an initial value to zero by modifying the phase difference. To confirm the efficiency of the proposed controller, simulations are conducted under two conditions: the one is that the wheel speed is zero, and the other is that the wheel speed has a constant velue. Under the first condition, the robot moves back and forth around an initial point and gradually changes the yaw direction. Under the second condition, the robot moves forward at a constant speed while its yaw direction gradually changes.

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A new real-time emergent stop method using modification criteria map is proposed for humanoid robots. The stable gait change is generated by adjusting the amount of the reference ZMP modification according to the timing of stop command. The modified ZMP trajectory is given so that the humanoid robot can change the current motion without falling down. The modification criteria are defined from the relation between the predicted ZMP trajectory using a preview controller and the support polygon. We make the map of relation among the reference ZMP modification length, the modification of step timing and the timing of the stop command for stable stop motion. The robot can execute the best stop motion referring to the predefined map. The validity of the proposed method is confirmed by experiments using a humanoid robot HRP-2.

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Leg-wheel hybrid locomotion on rough terrain for a hexapod robot is realized by continuous transition between wheeled and legged locomotion based on sensor feedback. In basic positioning on a flat surface, the robot is supported by three legs and moves using its wheels. Upon sensing an obstacle, the robot's support and swing legs change as a tripod gait to cross over the obstacle. We define the three dimensional model of the motion on a slope for stability estimation, and its analysis indicates that the maximum obstacle height depends on the robot's height and the slope gradient. Even if the slope is steep, the robot can climb over a higher step on it by moving the robot's center of gravity (COG) based on the analysis. The experimental results on ASTERISK H confirm the advantage of proposed motion by comparing to the fixed COG motion.

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This paper proposes the control strategy for throwing manipulation. In throwing manipulation, the robot's motion is dynamic and quick and there is transition of contact state between the robot and an object. These make it difficult to obtain the exact model and solve its inverse problem. In addition, since the throwing manipulation requires more powerful actuator than the static manipulation, we should set the control input by taking consideration of the performance limits of the actuator. We propose the control strategy based on the iteration learning to overcome the abovementioned problems and verify its effectiveness experimentally.

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This paper presents an approach to modeling the hysteresis nonlinearity of pneumatic muscle actuators and to coping with undesirable hysteresis effects in controlling a manipulator consisting of pneumatic muscles by using a hysteresis model. The hysteresis model is constructed in the form of the Preisach model originally developed for magnetic materials and is used to describe hysteresis nonlinearity in the relationship between the contraction and internal pressure of pneumatic muscle. This model is also used for control of a parallel manipulator driven by three pneumatic muscles. The control system is based on contraction motion control system of each muscle that is composed of a contraction controller reinforced by an internal pressure controller and a feedforward controller that works to produce inputs in order to compensate for hysteresis behavior of the muscle. In addition, a component for switching the hysteresis compensator using a learning vector quantization neural network is attached to the system in order to overcome performance deterioration caused when the manipulator handles external objects. Experimental results show that incorporating the hysteresis compensator leads to an improvement in the control performance of the pneumatic muscle manipulator.

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Wearable computing has been actively investigated as the dimensions of a device such as a computer, a sensor, and a motor are getting smaller. In this work we focus on visual information sharing and our aim is to develop an image stabilization system for visual information sharing between humans. We use a small-sized-humanoid robot to simulate a person who captures visual information at a distant site. The developed image stabilization system can be used for an advanced wearable telepresence system. The requirements of an image stabilization system that can be applied to a wearable system are compactness, lightness in weight, and real-time process rates. We have implemented our image stabilization system to satisfy these requirements. The developed system uses a three-dimensional motion sensor for camera rotational motion detection, the optical flow for camera translational motion detection, and the image-processing method for motion compensation. The experimental results show that images from the camera mounted on the small-sized humanoid robot can be stabilized by our developed system.

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This study discusses the effects of the Steer-By-Wire (SBW) technology on the lane keeping performance for two-wheeled vehicles by examining computer simulation with a rider-vehicle system which consists of a simplified vehicle model, a rider control model and the controller of the SBW system. The SBW system, which compensates the rolling angle deviation between the desired rolling angle intended by the rider and the actual rolling angle, improves the lane keeping performance of the rider-vehicle system in comparison with conventional two-wheeled vehicles under the steering torque disturbance. The SBW system is, on the other hand, not effective for the lane keeping performance under the lateral force disturbance. In addition, the Lane-Keeping-Assistance (LKA) system is applied to the SBW system and the cooperativeness of the SBW and the LKA systems is examined. The LKA system improves the lane keeping performance of the SBW system under not only the steering torque disturbance but also the lateral force disturbance.

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A steering command from the driver to an active steering vehicle can be excessive, especially in lower road friction conditions. The present paper discusses protection functions for active steering vehicles. The grip margin is defined as the residual tire force normalized by the radius of friction circle. The isotropic brush model is reanalyzed so that a cubic equation for the estimation of the grip margin can be obtained. A protection function similar to that used in fly-by-wire aircraft is developed for active steering. This protection continuously updates the upper bound for a steering command according to the present vehicle state and the estimated grip margin. The proposed scheme is simulated using CarSim and the numerical results show their basic functionalities.

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A novel mechanism CVT (Shaft Drive CVT, S-CVT) was developed by the authors. The use of zero-spin disk and roller was proposed in order to increase the power to weight ratio, because the power to weight ratio is important index for applying the S-CVT to automobiles. The amount of spin caused by the changing in the contact point is less than 0.9% using the zero-spin disk and roller. Their performance has been confirmed theoretically and by the experiment. In this report, the effect of novel zero-spin disk and roller is evaluated using a prototype CVT. A hydraulic cylinder is equipped to give a large loading force. A counter shaft, which connects the two backup rollers to transmit the torque between them, is added to enlarge the torque capacity. The power to weight ratios are improved to 1.4 and 3.0 times compared with those of present concave disk at high and low ratio, respectively. The maximum value is 72.3W/kg at high ratio in the case of transmitted torque of 195Nm.

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This paper shows a new strong coupling analysis method for calculation of hydrodynamic lubricating film characteristics on the stern-tube-bearing of large-sized ships. The dynamic forces on the propeller shaft in turning conditions were calculated using CFD. Then, the propeller shaft center loci were calculated using dynamic propeller shaft forces, and were compared with the results of measurements of shaft center loci of a full-scale ship, where the results showed approximately good coincidence, thereby the validity of this analysis was confirmed.

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Such advantage as a high ratio of strength to mass has rapidly raised demand for aluminium alloy composites. Their low hardness compared to steel makes aluminium alloys easy to machine, but this can be outweighed in certain applications by their low melting point and high ductility, which make aluminium chips adhere strongly to the tool edges, leading to tool breakage. Then many machining technologies such as machining fluid, fluid supply method and tool surface coating have been developed and, however, they cannot solve the problem of adhesion in practical use. In particular, the tool breakage occurs frequently in rolled thread tapping process. To overcome the problem, the ways to improve the anti-adhesive effect of tapping lubricant were studied, namely, the water-soluble lubricant with the introduction of fatty acid having good anti-adhesive effect was developed. Furthermore, the surfactant which was contained in the lubricant was selected considering replacement energy effect. The proposed lubricant had high corrosion resistance and low environmental impact, compared to the commercial tapping lubricant containing cation such as alkanolamines. From a series of tapping experiments for aluminium, it was found that the newly-developed lubricant brought high anti-adhesive effect.

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Sealing of contained fluids is the primary performance required for pipe flange connections. It is well known that the leakage is likely to occur when contained fluids at high temperature are concerned. Due to the differential thermal expansion of each part, bolt preloads that tighten a pair of pipe flanges tend to decrease. Therefore, it is significantly important for the joint safety to estimate the amount of bolt preload reduction at the design stage. In this paper, a finite element approach is proposed to analyze thermal and mechanical behaviors of pipe flange connections at elevated temperature, by incorporating the stress-strain curves of sheet gaskets measured in the previous paper. Then, the reduction rate of bolt preloads at elevated temperature is systematically evaluated. The analytical objects are pipe flange connections tightened with aramid sheet gaskets. When a pipe flange connection is subjected to thermal load, the gasket stress usually decreases along unloading curves. The temperature dependency of gasket stiffness is considered by defining Young's modulus in unloading E^*, which can be introduced into FE formulation using ordinary solid elements. Numerical results show that bolt preloads are decreased by as much as 30% of the initial value when using aramid sheet gaskets of 3mm thickness. The effectiveness of the proposed numerical method has been confirmed by comparing the numerical results of bolt preload reduction to experimental ones.

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Nickel electroforming is used as a fabrication technology of micro metal mold including LIGA process. However, neither the strength nor peelability of electroformed nickel is enough. There are several methods that is alloying or using additive composition of electroplating bath to improve strength of the nickel mold. In this research, we improved the hardness of the nickel mold by electroforming. We used sodium allylsulfonate as an additive for hard nickel electroplating. The hardness was approximately 600Hv and kept the property after annealing of temperature 250℃. The abrasion resistance was approximately 41 WR after annealing of temperature 250℃. Finally, we fabricated double layer nickel mold has micro pattern and the thickness of 4mm.

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In recent years, electric devices have rapidly advanced in high performance and miniaturization. As a result, electric circuits on Printed Wiring Boards (PWBs) are becoming high-density and its layers are increasing more and more. Therefore, micro-via drilling technology using a laser has become the dominant method for drilling blind via-holes (BVHs). Cu-direct laser drilling has attracted attention as a new method. However, there are few reports dealing with Cu-direct laser drilling of PWBs. Especially, when the copper and the resin with a different processing threshold are drilled at the same time, a defect of the overhang occurs on the drilled hole. However, the overhang generation mechanism has not been clear. Therefore, we investigated the overhang generation mechanism by observation of drilled hole section in detail. Moreover, we estimated the influence of thermal conductivity of the build-up layer on the overhang length using finite element method (FEM). As a result, it was shown that the overhang length becomes smaller with thermal conductivity of the build-up layer increasing. Therefore, we carried out an experiment with prototype PWBs silica filler mixed in the build-up layer. Using the prototype PWBs, it was shown that overhang could be reduced as shown in FEM analysis results.

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In recent years, 5-axis control machining has attracted a wide attention because of having many advantages compared with 3-axis control machining. However, there have been few roughing procedures corresponding to 5-axis control machining. This study especially deals with roughing by 3+2-axis control machining, which performs 3 translational axes machining after determining a suitable tool axis vector by 2 rotational axes movement. For 3+2-axis control machining, the determination of tool axis vectors, tool lengths and tool diameters largely affects the rough machining time. The previous study proposed a method of determining the optimal tool axis vectors and selecting the tool diameters for efficient roughing. In order to improve the method more effectively, this study proposes a new method of searching optimal tool combinations by taking account of shorter tool length. Stiffness of short tool is so high that it can machine workpiece more efficiently. The effectiveness of the proposed method was demonstrated by the machining simulation and experiment.

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Attractive product is changed significantly by requirement definition and conceptual design phases. Quality of product concept, which is result of these phases, depends heavily on creativity of designer or development team. Therefore, it is difficulty that computer-aided system supports a creative and inventive thinking process, to search a creative design solution. To overcome its difficulty, we survey study results of this thinking process at engineering design and inventive problem solving fields. Based on this observation, this paper proposes a systematic approach of the creative and inventive thinking process for Creative and inventive Design Support System (CDSS). The proposed approach is combined problem understanding and solving processes to simplify its thinking process. In addition, we introduce three methods-contradiction understanding and solving methods and the invention principle of TRIZ-to this approach. Its validity is ascertained through applying to the conceptual design of walk assist machine for the old age.

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In recent years, industrial designers are required to design creative products in a short period of time. Attractive product is changed significantly by requirement definition and conceptual design phases. The Quality of product concepts, which is result of these phases, depend heavily on the creativity of designers or development teams. It is difficult that a computer-aided system supports a creative and inventive thinking process, and searches a creative design solution. To overcome these difficulties, authors developed a systematic approach of the creative and inventive thinking process called Creative and inventive Design Support System (CDSS). In this paper, its validity is examined by using to the Design of Experiments (DOE) and the Taguchi Method. From these evaluation results, it is confirmed that creative design solutions can be searched by using the creative and inventive thinking process of CDSS.

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Quantitative risk assessment of large and complex system developments is becoming a mainstream global trend for risk management. However, qualitative risk assessment such as preliminary hazard analysis (PHA) is extremely crucial in promoting inherent safety design in the early phase of development. Therefore, qualitative risk assessment will play an increasingly important role in complementing quantitative risk assessment. Compared with previous developments, inherent safety design is being pursued more thoroughly as product development becomes larger and more complex. On the other hand, many engineers share their work loads and have more interfaces in their projects. Under these situations, hazard identification and risk evaluation in qualitative risk assessment should be improved with quantified expression. This paper presents a methodology of quantification and approximation formulas for better consistency and information sharing of qualitative risk assessment.

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"Trapped key interlock" is an alternative to "lockout" for controlling hazardous energy in order to protect the machine maintenance personnel working at any place where they could be injured by the unexpected release of hazardous energy. In view of the above, this paper proposes that the relation of "locking up the power switch in the OFF position," "picking up the key for hostage control" and "unlocking the movable guard for accessing to the working area" should be made unite in terms of system by applying the "principle of safety confirmation" to the "trapped key interlock." The points in designing such unite system are that the movable guard should be unable to be opened unless the key for hostage control is picked up by the machine maintenance personnel and that the key for hostage control should be unable to be inserted into the key hole unless the movable guard is closed. To realize these points, this paper formulates these interrelations, presents them in the form of interlock structure and shows an example of configuration that can meet the required safety functions.

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