Servo signals, such the focusing or tracking error signals of an optical head, are generated from the position or the intensity distribution of the beam spot on the detector. If the beam spot position on the detector deviates as ambient temperatures change, the servo signals fluctuate. Therefore, reducing the position deviation is necessary in order to obtain highly reliable reading or writing operations. We derived a formula where the position deviation of the beam spot on the detector with temperature is approximately expressed as a linear combination of the factors of the position deviations caused by displacement and tilt of each optical part. To reduce the position deviation of the beam spot, we developed a method where effect of one optical part on the position deviation offsets that of another optical part. Using this method, we developed a jisso structure of a slim optical head utilizing a resin housing. The measured position deviation on the detector is 6.2% of the diameter of the beam spot or less at ambient temperatures between 0 and 65°C.

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Using the reduction gears with inclined planetary gear and arc tooth bevel gear, the vibrational accelerations in vertical direction of this system, with and without the backlash, are measured by changing the load torque and the input shaft speed. And, the materials of cylindrical pin attaching part of fixed and output gears are changed to alloy tool steel and cast iron, and the vibrational accelerations of this system are measured, and the results are discussed. The results are as follows : In the vibration characteristics of this system, meshing frequency component is main, and the natural frequencies caused by the torsional vibration of gears and the vibration of casing supporting the input shaft, are appeared. The vibrational acceleration of the system without the backlash is slightly lower than that with the backlash. Meshing frequency component has remarkably appeared in the vibrational acceleration, when the material in the cylindrical pin attaching part was changed from alloy tool steel to cast iron. However, in this system, the effect of the high damping capacity of gray cast iron has not appeared.

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Many classes of nonlinear systems can be represented by Volterra kernels. The authors have recently developed a method for identification of Volterra kennels of nonlinear systems by using M-sequence and correlation technique. In this paper, the authors propose a new method for identification of nonlinear mechanical systems by use of Volterra kernels. The nonlinear mechanical systems are approximated to a nonlinear vibrating system which consists of a mass, a dumper, a linear spring and a nonlinear spring. Then, the parameters, which represent the nonlinear springs are calculated by use of the Volterra kernels. From the results of computer simulation and experiment, the parameters that represent the nonlinear characteristics of the nonlinear mechanical systems can be identified by the proposed method.

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Transient Statistical Energy Analysis (TSEA) is a suitable tool to predict transient sound and vibration especially in huge structures like ship-buildings under the shock excitation. This paper discusses the governing equation of TSEA by using a system which has two identical oscillators coupled by a spring. Firstly, the exact energy response of each mass is determined analytically. Then an exact power balance equation with limitation for this system is newly derived from the exact energy responses. Numerical simulation is carried out in order to compare the results predicted by the TSEA and the exact power balance equation with exact solutions. It is shown that the responses predicted by the TSEA are earlier and larger than the exact results when the system has the ratio of coupling loss factors to internal loss factors less than 1.69. It is also shown that the earlier and larger results by TSEA are dependent on the initial transmitted power from the source subsystem to the receiver subsystem which is unreasonable transmission.

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Band-gap structures can inhibit the propagation of waves in certain frequency ranges, or bands. Phononic band-gap structures that inhibit certain acoustic and elastic waves from propagating have received a great deal of attention recently, and have great potential in engineering applications, as it is hoped that they can be utilized as sound or vibration protection devices, acoustic lasers, acoustic mirrors, frequency filters and waveguides in mechanical structures and MEMS. This paper presents a new structural optimization method for the design of more generic and extendible phononic band-gap structures using discrete structural elements, based on topology optimization techniques. The use of a variety of discrete structural elements has the advantage of enabling the design of higher performance or more sophisticated structures. In addition, in this research, a new objective function is proposed that enables several bands to be simultaneously considered as optimization targets, in contrast to the objective function typically employed in existing design methods for phononic band-gap structures that considers only a single band where attenuation is desired. Using this new objective function, structures incorporating band-gap effects across multiple eigen-frequency bands can be created. The resulting optimal configurations have the potential to dramatically reduce the propagation of waves in specified frequency ranges. Furthermore, several numerical examples confirm the validity and utility of the proposed method.

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In this paper, a method to identify the geometrical shape and the location of the defect embedded in a concrete structure by processing the thermal image of the structural surface acquired by infrared thermography is presented. In the proposed method, the structure is modeled as a homogeneous infinite plate whose boundary condition on the observed surface is known. A layer-by-layer inverse analysis using a regularized interlayer transfer matrix based on 2D Fourier transform is carried out to obtain the sharper image of the defect as well as the depth of the damaged layer. The estimated depth information mapped on the image plane has resulted in a “depth image” which can display the shape of the defects and their depth simultaneously. The effectiveness of the proposed technique has been examined both numerically and experimentally.

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Lure fishing and fly-fishing have been positioned as sports deliberately different from the traditional Japanese fishing-style. In the case of fly-fishing, casting is the element which anglers must master in order to cast a fly, done so by using the weight of a line. This study uses experimental and computational analysis to investigate the dynamic behavior of a fly line. Fly-fishing constitutes various elements, but the importance that casting holds is extremely large. Fling speed, the casting process and the loop shape of the line while in flight are important for the proper presentation of flies. Moreover, the shape of a fly line is also important for a long cast or controlled cast. However, it is difficult to grasp the phenomenon or to make a numerical model because a fly line is an object of flexible string. Therefore, the most suitable casting method will be clarified from the viewpoint of sports engineering and human dynamics. In addition, measuring an angler performing movements with a flexible object such as a rod or a line is difficult. So establishing a method to measure the dynamic behavior precisely is also one of the purposes of this study. Anglers usually do “double haul cast” in the actual fishing field in order to put a fly for long distance and in order to control the line orbit. “Haul” means pulling the line compulsory. This technique increases the line speed and kinematical energy. Therefore, the line flies long distance. In this paper, the effect of “Haul” is investigated.

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A phenomenon that passengers are getting sleepy is often found in running cars or trains. If a mechanism can reproduce this phenomenon, it is feasible to put insomnia patients or infants to sleep without any harmful effects. This will bring extreme benefit for insomnia patients or parents of babies. The purpose of this study is to elucidate the sleep-inducing factors of running cars or trains, and the final goal is to develop a machine which reproduces the environment to put people to sleep. For the first step of this study, we investigated the relationship between sleepiness and vibrations on several trains. The sleepability of each train is discussed by the ratio of sleeping passengers. According to the vibration analyses, the results suggest that comfortable vibration for sleep has mainly low-frequency (2 Hz) vibration with particular fluctuation. In addition, it is also guessed that low level jerks contribute the sleepability.

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The floating roofs are widely used to prevent evaporation of content in the large oil storage tanks. The 2003 Tokachi-Oki earthquake caused severe damage to the floating roofs due to liquid sloshing. The structural integrity of the floating roofs for the sloshing is urgent issue to establish for the petrochemical and oil refining industries. This paper presents the axisymmetric finite element analysis for the sloshing response of floating roofs in cylindrical storage tanks. The hydrodynamic coupling of fluid and floating roof under seismic excitation is taken into consideration in the analysis. It is assumed that the fluid is incompressible and inviscid, and the roof is linear elastic while the sidewall and the bottom are rigid. The theory for the finite element analysis in which the behavior of the fluid is formulated in terms of dynamic pressure as the Eulerian approach is developed. The basic vibration characteristics of the floating roof, such as natural frequencies and vibration modes, can be obtained from the analysis. These give engineers important information on the floating roof design.

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We have proposed a magnetic levitation control system for a sheet steel and confirmed the realization by a digital control experiment. However, because of the strong nonlinearity of the attractive force of the electromagnet and the various uncertainties in the circuit current such as changes in the resistance due to heat generation of the electromagnet, stability of levitation has not been sufficiently ensured. In this study, we aim to develop a noncontact support system for thin steel plates with high robustness using sliding mode control, which is tolerant to factors such as disturbances within control signals and external forces affecting the system. As a result, it was verified that the suppressive effect of the sliding mode control on disturbances is sufficient, and that the application of the continuous model provides the construction of a system with robustness to the disturbance of the external forces.

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This paper presents a control design method considering both non-linear characteristic of a structure and non-stationary characteristic of earthquake motions for the purpose of reduction of the building response subjected to earthquake. A building with base isolation system whose rigidity is bi-linear hysteresis during non-stationary disturbance such as earthquake is dealt with and the optimal control system is obtained by applying the equivalent linearization technique. First, the equivalent linearization of the non-linear structure is performed by using the 2nd moment of the building responses such as displacement, velocity, acceleration, etc. Next, a non-stationary model of ground motions is shaped from white noise. And an augmented model is made by including the equivalently linear model of non-linear structure and the non-stationary disturbance model. Finally, the optimal control system for the augmented system is obtained. In order to investigate the usefulness of the proposed method, computer simulation is carried out and this method is verified.

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We study the motion, vibration and contact force control of the flexible master-slave system (FMSS). In this study, the master arm is a one-link arm that consists of a rigid body and the slave arm is a one-link arm that consists of a flexible link. The bilateral control based on passivity and the optimal control based on the linear quadratic regulator (LQR) are applied to the system. Each of those control methods has some advantages and disadvantages. We employ the state observer to construct those controllers. However, the accuracy of state estimation is deteriorated while the slave-arm contacts with objects. Therefore we improve the accuracy of the state estimation by applying the disturbance-state observer. We indicate the performance of the present method by experimental results.

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For the precision measurement and positioning, active anti-vibration apparatuses have been widely used. In order to improve the transmissibility of its apparatus, the control scheme that had the function of air spring stiffness canceling was previously proposed. In the proposed control loop, optimal triple parameters are in existence. In the industrial field, strict parameter tuning like optimal condition is hateful, because the specification of apparatus must be assured under the condition of parameter fluctuations. In this paper, using an orthogonal table L₃₆ well-known in the quality engineering, a tolerance design method is proposed. Firstly, the control diagram of air spring type anti-vibration apparatus is shown. Next, the Linear Fractional Transformations is applied to its control block in order to express the parameter fluctuation. Furthermore, the table L₃₆ is also introduced. Finally, based on the analysis of variance against L₃₆, it is shown that the parameter tolerance is decided.

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In the preceding paper we developed an optical three-axis tactile sensor capable of acquiring normal and shearing force, with the aim of mounting it on a robotic finger. Normal force and shearing force applied to the sensing element were detected separately ; when we examined repeatability of the present tactile sensor with 1 000 loading-unloading cycles, the respective error of the normal forces was 2%. In the present paper, the three-axis tactile sensor is mounted on a robotic finger of 3 degrees of freedom to evaluate the tactile sensor for dexterous hands. In a series of experiments, three kinds of experiments are performed. First, the robotic hand touches and scans on flat specimens to evaluate ability of surface condition. Second, it detects contour of parallelepiped and cylindrical objects. Finally, it manipulates a parallelepiped case put on a table by means of sliding on the table. Since the present robotic hand was able to perform the abovementioned three tasks with appropriate precision, we prospected that the hand was applicable to the dexterous hand in the subsequent studies.

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This paper proposes a new switching method of control mode for a robot manipulator coming in contact with environment that has elasticity. First, the basic concept of the switching of the control mode in a robot manipulator is explained. Second, we propose a new method of switching the control mode that selects the control mode at the intersection of “Characteristic curve of position and force” and “Target value of the work composed by the desired value of position and force”. Next, the switching algorithm based on this method is obtained about a certain work coordinate with a Multi-DOF robot manipulator. In this paper, the switching method is named “A Method for Switching Control Mode Based on Position and Force Errors”. Furthermore, when a One-DOF robot manipulator driven by DC servo motor with reduction gears using an elastic joint came in contact with the object that has elasticity, the simulation and the experiment on various angle and torque controls were done. As a result, it is shown that the proposed switching method is useful and has stable and flexible characteristics.

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For the stable grasping of the object with the robot hand, autonomous grasping force control based on partial slip sensation is known to be effective. To realize dynamic dexterous manipulation, however, slippage between robot finger and the object must be allowed. This paper proposes a novel master-slave system that realizes control of grasping force for conducting stable grasping without slippage and manipulation with slippage according to the operator's intention. In the proposed system, the slave robot automatically controls grasping force based on partial slip information, while the master device applies virtual slip to the operator. Operational intention will be estimated based on the change of grasping force of the operator responding to the virtual slip stimulus. Autonomous grasping force control and operational input are coordinated by suppressing autonomous control according to the estimated intention. The developed partial slip sensor contains strain gages in several ridges placed on the curvature contact surface of the elastic body. By measuring strain velocity of each ridge, the vibration that occurs due to the partial slip can be detected. The virtual slip is displayed by applying dynamic friction force with master device. The formation of virtual slip stimulus is based on the results of psychophysical experiments. Through the grasp manipulation experiments with the developed master-slave system, the validity of the proposed system was confirmed.

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We have studied concerning the design technique of ankle-foot orthosis (AFO) that is used spastic hemiplegia of the stroke. We developed the equipment for measurement in order to measure the influence which it causes to spasticity gait. The ankle joint moments are calculated by the measurement data. In addition, you appraised of gait lability as the scatter plot by the angle and the moment of ankle joint in heel contact. These appraisal results were made the element which selects the orthosis. The design of the orthosis was utilized three dimensional cad, and the structural of the orthosis was analyzed the non-linear finite element analysis by the boundary condition which utilizes the measurement data. In this study, the life prediction of the orthosis which deals with 2 orthosis users was made help of the design factor. In order to investigate the life cycle of the orthosis user, the number of steps and living conditions were investigated. As for material definition S-N curve of the PP material was used. The result of fatigue analysis, it was suggested that fatigue analysis of the orthosis is effective as the help in orthosis designing.

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This paper presents the validation of optimal driving force distribution and steering angles of multi-wheeled vehicles with independent wheel drive and steering. The optimal driving force distribution and steering angles to the wheels were formulated by minimizing the total slip loss of all the wheels of the vehicle. Numerically obtained optimal driving force ratio and the steering angles were imposed to each wheel motor of a model size eight-wheeled vehicle for steady turn experiments. In order to validate the efficiency of the vehicle steady turn, the total driving force or total driving force squared of the wheels was measured and compared to that of the other driving force distribution methods. The experimental results showed that the proposed method of optimal driving force distribution and steering angles reduces the total driving force of multi-wheeled vehicles, and is efficient on small turn.

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This paper presents the sensitivity analysis of multi-body dynamics (MBD) model for automobile suspension systems, where the geometry of joint as well as mass, stiffness and damping coefficients are design parameters. By this method, we can ascertain which elements contribute for the dynamic characteristics of the system. This paper mainly focuses on the effectiveness and advantages of sensitivity analysis. The effectiveness of the sensitivity analysis for MBD system is verified by comparing with the response surface approach. The optimization of dynamic properties of the suspension system based on the sensitivity analysis is also examined.

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Some part of the occupant's kinetic energy is transferred to the vehicle through the seat belt during a car collision. The high ratio of the transferred energy has the advantage in protecting the occupant. This phenomenon is called “ride down effect”. In order to design an automotive body structure with consideration of the ride down effect, the dynamic relation between the occupant deceleration, which is one of important injury criteria, and the automotive body structure must be studied. However, there have been few researches on the phenomenon of the ride down. In this paper, we verified the theory of the ride down effect by using a 2 DOF experimental model for a vehicle and an occupant to analyze the dynamic mechanism. Moreover, the relationship between the index of the ride down effect and the occupant deceleration was experimentally investigated, and automotive designs with the minimum deceleration in crash was examined.

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This study proposes how a humanoid robot can perform surfing without force sensor. Usually, it is impossible to control surfing robot only with its center of mass information, because the change of gravity direction cannot be measured without force sensor. However, this study attempts to clarify the possibility of the control for the humanoid surfing without force sensor by using estimated joint torque information from its motor current. Several control methods are proposed to realize the surfing robot without force sensor by using approximate ZMP estimation method based on the motor current information. These experimental results show not only contribution of sensorless control method but also interesting stability discussions that consists of both static stability and dynamic stability problem. All of both cases are for maintaining its standing stability under change in direction of gravity.

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The aim of this study is to investigate the right position for installation of a visual display of Car-Navigation system. The method of this research is to consider about the effects of presenting auditory information on the positional perception of driver from the experimental approach. The evaluation indices are measuring the saccadic time, the stationary time and the reaction time from the movement of the subject's fixation point. The results shows following : (1) Since an auditory information plays an important role in the information processing on positional perception, the visibility time, the saccadic time, the stationary time and the reaction time become small by presenting auditory information. (2) The bigger the vertical instillation angle from the glabellar point to the position for installation of a display becomes, the bigger the effects of presenting auditory information on the positional perception is. Based on an analysis of fixation, it is seen that the saccadic movement is possible to do smoothly on the narrow vertical direction in useful of view by presenting auditory information.

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The detached houses have the first natural frequencies in higher range, and their structural deflection is small even though their response acceleration is high. Therefore, the deformation transmitted to damper becomes small, and the dampers have to be designed to obtain a desirable performance against such small amplitude vibrations. For this reason, the new type of damper having the amplification mechanism was developed to solve this problem in this study (“pipe-type-damper”). This paper reports on the results obtained from experiments and analysis of a detached house model using dampers. In the experiments, the trial damper of Itf capacity was made, and the experiments were performed to investigate the fundamental characteristics of pipe-type-damper. As a result, the properties of pipe-type-damper were expressed by the non-linear-4-element model, its restoring force was proportional to the second power of amplification factor by the amplification mechanism. Analytical results obtained by considering the characteristics of damper showed that the pipe-type-damper had good vibration control performance.

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In this article, we propose a standing-up motion support system for elderly people and physically-handicapped persons, which make the comfortable and stable human posture change based on physical and motion characteristic. This system applies physical characteristics of the user to the human body model based on Kinaesthetics which is introduced into the field of nursing in these days. Effectiveness of a human support system is evaluated by using joint torque and PHM (Posture Holding Moment). We demonstrate the effectiveness of standing-up motion support system by using these evaluating measure.

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This paper describes a new method to utilize redundancy of hyper redundant robots. To achieve dexterous motion of hyper redundant robot, joint inputs should be determined by taking account of i.e., the contribution of all actuators for the achievement of target motions and capability for unpredictable target motions in future is necessary. Two evaluation indices, the movability index of each link and the assistability index for target motion, are thus formulated with the angle distribution of column vectors of Jacobian matrix for each link. Then joint input to maximize or minimize these indices are derived based on an improved gradient projection method. The physical meaning of the proposed indices is also discussed by comparing with conventional manipulability measure. Motion control simulations and experiments with a planar 10R serial manipulator revealed the effectiveness of the proposed method.

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The first report describes longitudinal surface texture was the best for improving the traction coefficient. Therefore, the longitudinal surface texture was optimized using the 4-roller tester. The test results made it clear that the groove depth, groove pitch and also the radius of curvature of the convex portion of the rolling elements are important parameters of the longitudinal grooves for improving the traction coefficient while assuring high durability at the same time. Furthermore, an attempt was made of increase traction coefficient of an actual CVT variator by using an optimized longitudinal surface texture. The test result proves that a traction coefficient can be improved by optimizing microtexture without spoiling durability.

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When a liquid is confined in nanometer-scale gaps, it exhibits characteristic viscoelastic properties that are different from those properties measured in a bulk state. In hard disk drives, a liquid lubricant film whose thickness is around 1-2 nm is used to lubricate the interface between the magnetic head and the magnetic disk surface. When the magnetic head touches the disk surface, the lubricant film is confined in the nanometer-scale gaps and sheared. In order to attain the proper lubrication, it is essential to investigate the dynamic viscoelasticity of the confined liquid lubricant under shearing motion. In this study, we focused on one of the typical phenomenon of the confined liquid which is referred to as the shear thinning. The shear thinning is the property whereby the viscosity of the liquid decreases when the shear rate or shear frequency increases. This can be observed in many lubricants in a bulk state. The characteristic behavior of the confined lubricant is that the shear thinning can be observed at much lower shear rates or shear frequencies compared to the shear thinning occurs in a bulk state. The mechanism of the shear thinning in the confined state must be different from that of the bulk state. In order to clarify the shear thinning mechanism of the confined lubricant, we measured the gap dependence of the viscoelasticity at different shear frequencies in a range of 100 Hz to 2 kHz. The experimental results showed that the shear thinning behavior suddenly appeared at gap width of approximately 15 nm or less. Further, the shear thinning synchronized with the enhancement of the elasticity which means the solidification of the liquid lubricant.

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To investigate the effects of ultraviolet (UV) irradiation on perfluoropolyether (PFPE) lubricants with identical main chains but different end groups, three types of PFPEs (UV sensitive AM3001, less UV sensitive but functional Zdo12000, and less UV sensitive and nonfunctional Z03) coated on magnetic disk surfaces at nanometer thickness were irradiated by 172 nm UV rays, and bonded lubricant thickness, surface energy, and lubricant spreading measurements were subsequently conducted. Over the irradiation time range investigated, Zdo12000 showed a linear increase in bonded thickness, whereas AM3001 and Z03 showed a saturating increase and the saturating bonded thickness matched the gyration diameter (2.8 nm) of bulk AM3001 and the cross-sectional diameter (0.7 nm) of Z03 molecules, respectively. For surface energy, except for Z03, the polar component decreased significantly with UV irradiation compared to the dispersive component, suggesting the preferential effects of UV irradiation on the functional end groups rather than the main chains. Spreading of AM3001 to bare disk surface was drastically decelerated by UV irradiation; for Zdo12000 and Z03, however, it was worth noting that the thickness profiles after UV irradiation changed to a layered structure featuring a forward-spreading shoulder. A peak/valley structure caused by molecular flow from the non-irradiated toward the irradiated areas was observed for functional AM3001 and Zdo12000, but was not observed for nonfunctional Z03.

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Draw and wall ironing (DI) is widely adopted for manufacturing of an aluminium beverage can. In the DI process, a large amount of DI lubricant is used in order to prevent to weld of metal matter board and form metallic mold. A synthetic ester emulsion type lubricant is mainly used as conventional DI lubricant, because the lubricant has high lubricity. In recent years, high safety and high hygiene of DI lubricant are strongly demanded and, however, the conventional lubricant cannot meet the demand. Then, to overcome the above problem, DI lubricant which consists only of the substance described in the FDA (Food and Drug Administration) standard list was developed. And micelle formation of fatty acid and alkanolamine was introduced to the lubricant in the hopes of bringing high lubricity. A series of frictional experiments revealed that the friction-wear properties for aluminum is correlated as well as the micelle formation of fatty acid and alkanolamine. Furthermore, it was found that the newly developed lubricant has the lubricity superior to commercial lubricant.

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Recently, aerodynamic bump foil bearings have attracted considerable attentions in oil-free turbo machines. However, the structure of bump foils is usually very complicated and it is difficult to fabricate these bump foils. This paper proposes a foil thrust bearing supported by visco-elastic material instead of bump foils. The structure of the proposed foil bearing is much simpler than that of a foil thrust bearing with bump foils. In this paper, the static characteristics of the proposed thrust foil bearing are numerically investigated and the experiment was conducted using manufactured test bearings. It was confirmed that the proposed foil thrust bearing could be easily manufactured and operate well as an aerodynamic thrust bearing.

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A movable machine tool with multi spindles and axes is newly developed which can efficiently process large-sized parts to expect an additional value. The main specification of the machine tool is not having the major construction such as bed, column and saddle, at all. Instead, the machine tool consists of only linear motor rails and beams to support. The developed machine tool can reduce the cycle time for cutting large size workpieces by means of multi spindles and axes, equipped with 6 to 9 spindles, and can simultaneously control up to 40 axes at maximum. In addition, the installation area of the machine tool is approximately 120% of area that the workpieces occupies. The previous reports explained the basic specification of the machine tool, its concept and performance evaluation, the management of simultaneous movement, the division of NC program for each spindle and interference avoidance, as well as the method of tool path generation to confirm the rapid production of large-sized die and mold. With measured results of parallelism, roughness, squareness, roundness, and bumpness, the study propose a new compensation method to improve the machining accuracy of the machine tool with multi spindles and axes.

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In order to obtain basic information on the improving the surface integrity of machined surfaces, the relationship between the residual stress of cut surfaces and the cutting edge shapes of cutting tools was examined. We used cutting tools that had various nose radiuses and cutting edge roundnesses to perform dry facing on a lathe. The residual stresses of the cut surfaces were measured by X-ray diffraction method. We found that when the rake angle was about zero degrees, the nose radius barely affected the residual stresses of the cut surfaces. However, when the negative rake angle was large, the nose radius significantly affected the residual stress. The residual stresses of the cut surfaces shifted compressive side when there was an increase in cutting edge roundness. The residual stress of a cut surface is kept in a high compressive state even though the cutting force decreases greatly due to grinding removing the rake side part of the cutting edge roundness.

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A necessity of an incident-reporting system has been conceived, but some problems for an effectiveness of the system can be still remained. The first is about a difference between a number reported and that practically occurred. Some researches indicate the difference can be affected by a management styles, such as a productivity and safety of a work place. This gap is attributed by a substantial limit of the incident reports that is, reporting is voluntary by a reporter and a manager has much difficulty for judgment whether the change in a number of reports owes not to a lack of a reporting effort but to an effect of measures. The second is evaluating difficulty for an effectiveness of the reporting system. A change in a number of reports, which is an only visible value for a manager of an organization, is not necessarily reflected by an actual change in an error frequency. Then it is difficult to evaluate the effectiveness only with the number of the reports. In this paper, we propose a quantitative shape indicator of a damage distribution of incident reports to evaluate this effectiveness. We observed the relationship between the pattern indicator we proposed and a number of a fatal incident reports in one Japanese hospital. The result showed a positive correlation in the two factors, as we predicted. This indicator can be reflected by an enthusiasm for reporting or an effectiveness of safety measures based on an experimental relation to the frequency of fatal incidents. Consequently, the concept we proposed is effective to consider the effectiveness of a safety management activity using an incident report for not only in a patient safety, but also in an engineering safety.

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In patient safety management fields, there are quite large number of incidents in which failures involved could easily be prevented by “already-known measures”. This paper describes the frame-work of learning “good practice” using incidents reports and worker's heuristics in order to take measures for the causes of the incidents. The proposed concept is applied to a safety management activity in Kyushu University hospital, which is one of educational central hospitals in Japan. A distinct number of reports collected from May 2005 to March 2006 is 1 635, which contains a cause of malpractice of checking is 65.9%, a cause of malpractice of process is 26.2% and other is 7.9%. By comparing local practices in sections to prevent failures in drug confirmation, the authors has determined effective practices, which we calls “acceptable safety rule” that achieves safety, efficiency in practice and the acceptance by workers or cooperative patients. Consequently, our proposed framework is validly effective to improve the contents of safety rule introducing a worker's experience, in order to create “acceptable safety rule” which is safe and does not disturb an efficiency of worker's action. This framework can be applicable not only in a patient safety, but also in an engineering system safety.

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This paper reports the use of a novel Pd-based amorphous alloy as a material for a glass lens molding die with diffraction gratings. The properties required of the amorphous alloy are as follows : (a) the amorphous alloy must be able to be deposited as a film with a thickness of more than 50 pm on a blank die ; (b) the alloy must not exhibit crystallization or oxidization and must not adhere to glass, when a glass molds on the die of the amorphous alloy in air ; (c) it must be able to ultra-precision machined (maximum surface roughness R_z of less than 30 nm) by single-point diamond turning (SPDT); (d) it must have a fracture strength of greater than 0.6 GPa. We employed a combinatorial search using combinatorial arc plasma deposition to search for an amorphous alloy that satisfied the above criteria. Pt-Hf-Zr-Ni amorphous alloy was selected from the results of the combinatorial search of Pt-Zr-Ni and Pt-Hf-Ni alloys. The Pt₅₁Hf₂₀Zr₁₇Ni₁₂ alloy satisfied all the above criteria and it was possible to fabricate a molding die by SPDT using it. The molding die was capable of molding a glass lens with diffraction gratings.

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The present study considers a new when-to-schedule policy in production scheduling based on our previous work. This paper proposes a hybrid when-to-schedule policy introducing a cumulative delay driven rescheduling and a forced rescheduling to maintain the quality of a current schedule, which can be applicable to the timing of rescheduling under dynamic environment with unforeseeable events. We examine, through some computational experiments, some properties of the proposed policy by applying it to single-machine dynamic scheduling problems with sequence-dependent set-ups and random arrivals of hot jobs where we minimize total setups as well as total frequency of rescheduling. It is also demonstrated that the proposed policy outperforms the periodic and event-driven rescheduling policy with less frequency of scheduling.

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In this study, Patir and Cheng's surface roughness model is introduced in a mass conserving elastohydrodynamic lubrication model of a dynamically loaded journal bearing and described consistent with the model of regular striations. The lubrication model is based on a modified Elrod's cavitation algorithm and pressure effect on viscosity is expressed by Barus's equation. The model was applied to a con-rod big-end bearing of an engine and the effect of surface texture, roughness and striations, on friction power loss was calculated. The friction power loss of the bearing with circumferential striations is the lowest and is as much as that of the bearing with a smooth surface. The friction power loss of the bearing with transversal striations is the highest. The friction power losses of the bearing with the surface roughness take the value between them according to directional ratio. The results also showed the pressure effect on viscosity plays an important role in the friction power loss.

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