With the recent miniaturization of semiconductor devices, the importance of thermal transfer control at the nanoscale has been attracting attention. In this study, we perform a fundamental study on topology optimization for the design of nano-thermal-controlled devices that show the desired function at low temperatures. The solution of the dynamic-elastic equation for phonons, which are responsible for heat conduction at the nanoscale, is used to formulate the optimization problem, and a sensitivity analysis based on the concept of topological derivatives is performed. The obtained design sensitivity is then used to construct an optimization algorithm for creating the optimal structure of the nanodevices.

In this study, we propose a novel multiscale shape optimization method for designing the shapes of periodic microstructures using the homogenization method and the H1 gradient method. The compliance of a macrostructure is minimized under the constraint conditions of the total area of the unit cells of the microstructures distributed in the macrostructure. The shape optimization problem is formulated as a distributed-parameter optimization problem, and the shape gradient function is then theoretically derived. The shape gradient function is calculated with the two state and two adjoint equations related to the micro- and macro structures. Clear and smooth boundary shapes of the unit cells can be determined with the H¹ gradient method. The homogenized elastic moduli of the updated unit cells are calculated and applied to the macrostructure. The proposed method is applied to a multiscale structure, in which the numbers of domains with the microstructures are varied and the optimal shapes of the unit cells and the compliances obtained are compared. The numerical results confirm the effectiveness of the proposed method for creating the optimal shapes of microstructures distributed in macrostructures.

This paper provides a perfectly isotropic level set based topology optimization method for multiple materials. The problem that the multi material optimal configuration depends on how the parameters are given, due to the asymmetric material representation, is fundamentally solved. Also this paper implements the method to adjust the geometrical complexity of optimal configurations with regularization parameter. First, a topology optimization problem is formulated based on the representation by the vector-valued level set function, and the method of regularizing the optimization problem is generalized for multi-material topology optimization. Next, an optimization algorithm is introduced, and a generalized topological derivertive with regularization and constraints is derived. Finally, an example of design optimization is shown to confirm the validity and utility of the proposed topology optimization method.

This research presents a level set-based topology optimization method for the design of acoustic metasurface using a two-scale homogenization method. First, a homogenization method is proposed for the system of acoustic metasurfaces based on previous works so that it can be combined with the topology optimization method. Next, an optimization problem is formulated, where an objective functional is expressed by a macroscale response of the metasurface, and material distributions in the unit cell are considered as design variables. A design sensitivity is derived based on the concept of the topological derivative and adjoint variable method. We choose a waveguiding acoustic metasurface as a target of optimization, and two-dimensional numerical examples are offered to confirm the validity of the proposed method.

CFRP shell structures have excellent structural performance based on high specific stiffness. However, fiber orientation of CFRP on free-form surfaces has been a challenge in actual manufacturing. In this study, we focus on the deployment manufacturing method, which is a solution to this problem, and propose a novel method for obtaining the optimal pre-form to support the manufacturing of free-form CFRP shell structures. The proposed method consists of two processes. In the first process, the optimal cutlines is generated introducing the concept of crack growth analysis, the optimal cutlines are generated by separating the boundaries of the elements according to the magnitude of weighted strain energy density. In the second process, the optimal deployment shape with the cutlines is determined. We formulate a shape optimization problem that minimizes the work mapping with large deformation from the planer deployment shape to the original free-form surface under the area constraint, and derive a shape gradient function. Then, the planer deployment shape is obtained using the H¹ gradient method. The effectiveness of the proposed method involving the cutlines generation process and the shape optimization process is shown through design examples.

A topology optimization method to design micro structures of sound-absorbing poroelastic media utilizing the homogenization method based on an asymptotic expansion is proposed in this study. Design sensitivities of homogenized properties with respect to design variables defined on nodes of a microscopic finite element model are derived by using the homogenization method and the adjoint variable method. Then, design sensitivities of macroscopic objective function, which is dissipated power in this study, with respect to design variables defined on nodes of a microscopic finite element model are derived by using the adjoint variable method. The design variables are updated by using Method of Moving Asymptotes (MMA). Here, the design sensitivities both in microscopic and macroscopic scales are verified by a numerical examples.

In this study, we propose a non-parametric shape-topology optimization method for tailoring the static deformation of micro-frame structures. The design objective is to minimize the sum of squared error norms for achieving the desired displacements on specified members. The shape gradient function, the size gradient function, the topology gradient function, and the optimality conditions for this problem are theoretically derived with the Lagrange multiplier method, the material derivative method, adjoint variable method, GSIMP method. The sensitivity functions for this problem are applied for the H¹ gradient method for frame structures. With the proposed method, the optimal arbitrarily formed frame structures will be obtained without any shape, size and topology parameterization while maintaining their smoothness. Optimum design examples are demonstrated and the results are discussed.

Lure fishing is a kind of fishing methods that using fishing lures as artificial fish baits and has been more and more popular among the world. The vibration lure is the regular item among fishing lures, which performs vibration to bait fish. In the present work, to enhance the vibration behavior of vibration lure with a real analytical condition, we propose a free-form optimization method to for fundamental frequency maximization design problem considering solid structures under external loading, and carry out shape optimization for a metal vibration lure. We use the fundamental frequency (the 1st order) eigenvalue as the objective function and maximize it subject to a weight constraint. As the optimal results, the fundamental frequency of a vibration lure could be enhanced to 2.20 times as much as its initial value considering the external loading (i.e. the water pressure and tractive force of fishing line), while the mass of the optimal shape satisfied the mass constraint during the optimal design process. As a comparison, we also perform a design optimization of the vibration lure without considering the external loading, whose fundamental frequency can be also enhanced over 2 times as much as its initial value, and we conclude that the external loading only made a slight effect on the optimal results.

Traditional engineering has focused on artificial things. But we should pay attention to natural things, too. We are currently making efforts to get to the goal faster and in a more effective way. In short, current engineering is tactics-focused. But if we consider that environments and situations change frequently, extensively and in an unpredictable manner, we should pay more attention to strategy. We should go wider and wider. Therefore, this paper takes up instinct. Although there are studies about it, they discuss only its sensory functions. But from the broader point of view, instinct plays a more important role. It helps us perceive the environment and situation correctly and helps us make an adequate decision to move appropriately. The octopus demonstrates what an important role an instinct plays. But to utilize it, we need to free ourselves from the Euclidean Space constraints, i.e., orthonormality and distance with units. Euclidean Space Approach works very well for a small number of dimensions, but when it becomes very large in the Real World, the curse of dimensionality emerges, and we cannot solve the problem. To deal with this difficulty, Non-Euclidean Space Approach is introduced in this study and performance indicator to help instinct is proposed which combines ordinal scale Mahalanobis Distance and pattern.

Performance Indicator to support instinct to make appropriate decisions how to take and regulate our movements is developed. This is motived by the fact that current engineering is relying too much on artificial things and mathematical approaches. In the real world, the number of degrees of freedom is extremely large, so that research results, most of them are based on Euclidean Space approach, cannot be utilized due to the curse of dimensionality. And further, most of them pursue tactics. Their research goals are fixed from the first and how we can get to the goal more effectively is their focus of attention. But with environments and situations coming to change frequently, extensively and in an unpredicted manner, it becomes increasingly important to how we find our goal. In short, our engineering up to now is problem solving and tactics-driven, but now we should shift more to problem setting or goal finding and strategy-focused. Instinct, as the octopus demonstrates, works very well for this purpose. But as the real world is getting more and more complex, complicated and changing, the need to support instinct is rapidly increasing. But currently there is no performance indicator to help us make decisions. This paper, therefore, introduces non-Euclidean Space thinking to overcome the curse of dimensionality and to free us from the constraint of Euclidean Space orthonormality and unit. This performance indicator Mahalanobis Distance-Pattern (MDP) Approach combines Mahanalobis Distance for ordinal scale and pattern for holistic perception.

To enjoy working together with machines on things team as proposed by IoT, we need to communicate with machines. What we share with machines is movement. So, we need to communicate with machines nonverbally using movements as we did between humans in ancient times. Currently, machines move as humans instruct. But the environments and situations change from moment to moment in an unpredictable manner, so, machines need to understand proactively what humans would like to do. In today’s soccer, players need to be prepared beforehand for the next possible formation. Proactiveness is most important in today’s soccer. Otherwise, flexible formation cannot be achieved. In the same way, machines must be prepared for the next move. If we introduce Reservoir Computing, we can introduce micro technologies and we can make adjustments on site with very small sensors and computers. So, we can augment human capabilities with these micro sensors and computers and communicate with machines nonverbally. Machines can understand what we want them to do and they move as we want. Thus, we can enjoy working together with machines on the same team by feeling the sense of togetherness.

Today, most of our engineering efforts are paid to satisfy our material needs. We pursue to produce better products. Thus, how engineering started is almost completely forgotten. We started engineering to make our dreams come true. This was a big challenge, because we attempted to produce what we could not get from nature. But we should remember that there are two needs for engineering. One is to satisfy our material needs to survive and to secure safety. These needs are shared with other animals, too. And to satisfy such needs, engineering developed and brought the Industrial Revolution. It brought us an industrial society and we started to work for others or work for external rewards. Division of labor and mass production were introduced, and they accelerated industrialization. But another important aspect of engineering to satisfy our human needs of psychologically satisfying us were gradually forgotten. But if we do what we want, we will get the maximum satisfaction and feeling of achievement. Such engineering should be revived and we should enjoy designing and producing what we want in our own way. In short, we love challenges and we should provide people with engineering tools for them to challenge. That will make our life a game. Then, we will be satisfied psychologically to the full extent.

Bike Sharing System (BSS) recently attracts much attention as a way of sustainable transportation. This paper proposes Localized Bike Sharing System(L-BSS), which targets users of common facilities and connects common facilities to local important places. We aim to clarify indispensable conditions for materializing L-BSS such as balancing user demand and supply, span of rebalancing, and composition of users. For this purpose, we conduct demand estimation of a target case based on empirical data for constructing a model of L-BSS using Life Cycle Simulation.

Environmental load reductions in transportation systems are essential for a sustainable society. In this study, a life cycle simulation model was developed for a transportation system including automobiles and public transportation. Life cycle simulation is a method for evaluating an environmental load of a product through its life cycle. To focus on total transportation demand and their teardown, effects by a temporal change of population pyramid were considered. We modeled this demand change of transportation and reflected it to life cycle simulation model. A case study was conducted on the transportation system including automobiles, buses, and trains in Suita, Osaka. The total amount of CO₂ emission and total material requirement were calculated over the next 25 years.

For the realization of a sustainable society, it is important to understand the essence of problems from multiple perspectives. It is valuable for upper elementary school students to experience that these problems can be solved by themselves through education. In this paper, tomatoes, a global food, are the subject of this study. To develop an online workshop that fosters creativity by confronting social issues with familiar ingredients and wisdom. In the workshop, we aim to learn the reality of food production by live broadcasting the live scenes of food producers and experiencing the real thing. The purpose of this trial is to develop a platform that connects producers and consumers through education.

It is difficult for manufacturing firms to maintain stable management by selling off products because of the intensification of international competition. As a means to confront this problem, the Product Service System (PSS) has been proposed. It can enhance economic rationality and creates environmental and social values. However, many examples show that it is not easy for manufacturing firms to shift to a service-oriented business model centered on PSS. As one of the factors, it is that the conventional organization culture affects the decision making and inhibits the rational decision making in the business selection. This paper proposes a method to identify the inconsistency between the organization culture that concerns the decision making regarding the business transformation of manufacturing firms and the external environment to which the manufacturing firms belong, and promote the transformation of the organization culture. This method enables more rational decision making of manufacturing firms, and supports manufacturing firms servitization.

Skill-sharing services have a potential for fostering regional development and mutual aid within the community through residents’ social participation. Despite the growing social demand for skill-sharing services, there are still few cases to utilize individuals' knowledge, skills, and other intellectual assets. In order to widely diffuse skill-sharing services, it is necessary to clarify customer’s circumstances (motivations and barriers to use services) and reflect on the service design process. However, there is a lack of knowledge and practical method on customer analysis of skill-sharing services. This study thus proposes a customer analysis model to support skill-sharing service design. To this end, this paper derives motivations and barriers of customers in skill-sharing services through a systematic literature review of extant researches related to customer research in the sharing economy and empirical analysis of actual skill-sharing service. The proposed model’s applicability is demonstrated by application to a pilot survey with university students. The application result revealed that skill-provider emphasized economic, social, and self-realizationally motivations and skill-user have strong economic motivations. This result will contribute to designing service content to be provided by skill-sharing services aligning with target customers’ preference and feature.

Communication robots have become popular, but at present they cannot be used effectively. In this research, we examined the use of communication robots to support a new lifestyle after the coronavirus epidemic. According to the Ministry of Health, Labor and Welfare, the new lifestyle is suggested, which people are requested to keep the certain distance, to refrain from going out and to make a habit of gargling and hand washing. Therefore, we made a prototype for the support of the new lifestyle and installed it to the communication robot Sota. By using the M-method, which is one of the design methods, the functions required for communication robots, such as watching user, giving advice, and cuddling up together, were extracted. In addition, the possibility of effective use of communication robots to support lifestyle of users was suggested by the evaluation experiment using the prototype to manage users’ health.

In recent years, with the increase in the number of foreigners visiting Japan, there has been an increase in multilingual information services for foreigners using digital signage and information robots. However, in the current services, users have to select their language, which often prevents flexible and natural communication like that between people. In this study, we have developed a communication robot system that can automatically identify the language used by users and communicate naturally. For this purpose, we have developed a projector lending guide robot that can identify the user’s language by acquiring the language setting of the user’s smartphone as well as by estimating the user’s language from the responses in the conversation.

There are two mechanisms of visual attention, which have different developmental processes. One is passive bottom-up attention and the other is active top-down attention. LED guide lights attract attention by the movement of light. Although such a bottom-up attention-grabbing display is intuitive, it has a disadvantage for constant use. In this study, we focused on the attention-inducing effect of the motion illusion to induce the illusion of motion in still images. The purpose of this study was to propose a display with high attention-getting effect by incorporating optical illusions. In this study, we used an illusory image of moving gratings to give the illusion of motion by placing black and white gratings in front of a gray background. To investigate the attention-inducing effects of illusory images, we conducted a visual search task with stimuli of illusory images that were not related to the task. In the visual search task, we tested whether the target in the upright disturbance was tilted to the left or right. As a result, we found that the optical illusion reduced the reaction time when guiding attention to the target. In addition, we measured the number of eye movements during the task and analyzed the number of gazes by using a gaze-measuring device. As a result, we found that the number of gazes decreased when the illusion induced the target's attention. The results suggest that the motion-induced optical illusion induces visual attention.

In game design, only the positive user experience, such as how to engage the player, has been focused on. However, negative user experiences, such as game addiction and accidents caused by smartphone use while walking or driving, are considered to be a problem. Therefore, the purpose of this study is to propose a methodology for game design to lead the player to the end of the game without spoiling the positive user experience of the game. In this paper, we discuss the effects of cognitive load on player motivation and user experience, and verify the possibility of motivational control by manipulating cognitive load in experiments.

The trade-off relationship between speed and accuracy has been well known in motor tasks. An error of a movement increases as speed of a movement. Fitts’ law formulizes the relationship between speed and accuracy. A number of studies have confirmed the validity of Fitts’ law in many kinds of motor tasks, although the reason why the law can give good regression of a movement duration on speed and accuracy of the movement has not been cleared. In this study, the influence of dynamics parameters of arms, the magnitude of signal-dependent noise, and a criterion of movement smoothness on Fitts’ law was investigated to gain the sight with regard to the speed-accuracy trade-off. Computer simulations of a reciprocal tapping task were examined, and as a result, it was revealed that the joint viscosity of arms affects the regression fitness based on Fitt’s law, in particular negative viscosity breaks down it.

In this study, the effects of exposure to a 50 Hz AC magnetic field (Bmax 180 mT, 10 minutes) on skin blood flow volume, skin temperature and lower limb volume after tourniquet compression (50-60 mmHg) of the upper calf under knee in healthy adults were examined in a double-blind manner. The AC magnetic field was applied to the calf and foot of the right lower extremity immediately after 10 minutes of completion of hemostasis, with magnetic field exposure or sham exposure for 10 minutes. Although blood flow volume was significantly reduced from baseline immediately after the compression hemostasis, magnetic field exposure significantly increased the change rate of blood flow volume during and after exposure to the magnetic field compared to sham exposure. In addition, magnetic field exposure significantly increased skin temperature and decreased edema volume earlier than sham exposure. However, the results of change rate of skin temperature and edema volume showed no significant differences between them. These results suggest that AC magnetic field exposure improves the edema caused by circulatory disturbance.

Various driver states are predicted during autonomous driving. Therefore, it is necessary to present information that can flexibly respond to behavior during autonomous driving. At that time, driver state estimation technology becomes important. In this research, we focused on the seat pressure sheet that can acquire the information only by sitting down. we measured seat pressure distribution using a driving simulator, and predicted driving behavior using a convolutional neural network. In this research, we predicted five driver states: "Forward gaze", "Cell phone use", "Distract (right)", "Sleeping", and "Distract (left)”. As a result, it was possible to predict with an accuracy of 78.8% in inter participant evaluation and 97.3% in overall evaluation.

In recent years, the concept of value co-creation, which has expanded from value creation, has become widespread. Value co-creation is considered as a process of interaction between the provider's offering of a service and the recipient's consumption of the service. If receivers perceive positive emotions as a kind of value, the process of recognizing their value creation is a matter of Kansei or Kansei engineering. In this study, we attempted to describe an ontology in relation to Kansei value creation. Specifically, we conceptualized value creation and value capture as a type of design model, and specified the relationship between them and the design elements that compose the design model.

There is a need for products that provide a high level of user experience and are capable of capturing a high market share in today's competitive marketplace. In the field of air conditioning equipment, there is also a requirement to evaluate the thermal environment from a psychological aspect and improve it with lower energy consumption. However, previous studies have evaluated hot and cold sensations based on subjects' self-votes. Therefore, evaluating the influence of human sensibility on the sensation of hot and cold has not been sufficient. This study quantitatively assesses the sensation of hot and cold by combining two methods. One method is measuring the difference between the temperature at the start of the hot and cold stimuli and the temperature at the time when the subject perceives the change of the stimuli. Another method is the biometric measurements based on Electroencephalographs. This paper discusses the possibility of detecting changes in inner sensitivity that have not been apparent previously by using biometric measurements.

In recent years, needs of users have been diversified, and it is necessary not only to simply improve the quality of the products but also to satisfy the potential needs of the users. Therefore, this study proposes an evaluation grid method system that extracts the diverse user needs and the related design variables by visualizing the evaluation structure of the user's products and services. In the conventional evaluation grid method, it took a lot of time and effort to make the evaluation structure diagram of the users because it was very difficult to put together a complicated and large-scale evaluation structure diagram in case there are a large number of people surveyed. However, the proposed evaluation grid method system can handle a lot of subjects, and the design variables can be quantitatively evaluated by weighting the importance degree. In other words, this system allows designers to clarify the design variables related user needs. This system is applied to UI design of SNS to explain its convenience and novelty.

We investigated the appropriate range of time window for calculating eye and head movement parameters in mental workload (MWL) estimation during automobile driving. Participants performed driving tasks with a driving simulator, and eye and head movement were measured by controlling their MWL with the N-back task. The eye and head movement parameters were calculated by changing a time window from 30s to 150s in increments of 30s. An anomaly detector of MWL was constructed with one-class support vector machine (OCSVM) by using the data of no N-back task (“None”). In each window length condition, we calculated the area under curve (AUC) for the binary classification between None and the highest MWL condition, the percentage of anomaly data, and the distance from the decision boundary. The results showed that time window of 30s had significantly lower AUC than the other time windows. In addition, the correlation coefficient between the subjective MWL score and the distance from the decision boundary monotonically increased from 30s to 120s and decreased at 150s. Therefore, we concluded that 60s to 120s is an appropriate range as the time window for MWL evaluation.

Recognition of a category inferred by a stimulus affects its perception. The effect of category recognition is important to understand customers’ perceptions of an artifacts in product design. In this study, we propose a hierarchical Bayes model of the category recognition process. We formulate the probability of a category recognition as a function of four parameters: a prior appearance probability of a category，a variance of a feature involved in a category, a difference between mean of prior feature expectation and of actual stimuli (termed a predictions error)，and an inverse reliability of a sensory stimulus. We analyze how these four parameters affect the category recognition. We found an interaction among the reliability of a sensory stimulus, the variance of a feature involved in a category, and the predictions error on what category a stimulus is inferred as. An increase in an inverse reliability of a sensory stimulus monotonously decrease maximum a posterior of the category，under the condition that a prediction error is smaller than twice of a variance of feature involved in a category．On the other hand，maximum a posterior of the category is convex upwards under the reverse condition. In addition to this, we found that an increase in an inverse reliability diminishes discriminability of classes. Specifically, an increase in an inverse reliability narrows a gap of maximum a posterior between a class with a small predictions error (its predictions error is smaller than its variance of a feature) and another class with a large predictions error (opposite condition of the small predictions error).

Sense of Agency (SoA) is the sense that an event is caused by oneself. In a context of man-machine interface, it has been proposed that the prediction error of operational response decreases SoA. We assume that the information contents of the operational response represents the prediction error and thus explains the extent of SoA. We use the negative free energy (i.e. log marginal likelihood) as the information content and formulate the extent of SoA as a function of prediction error(difference between prior mean and likelihood peak) and sensory precision (inverse variance of likelihood) with a Gaussian Bayesian posterior. The model predicts an interaction effect between prediction error and sensory precision on SoA. We conducted an experiment of a mouse clicking task with participants. Between single cue (only sound or only vibration) and multiple cues (sound and vibration) operational responses are compared with respect to the effect of response delay as prediction errors on participants’ report of SoA score. We assumed multiple cues provide more temporal precision of sensory response than single cue based on cue integration theory. The experimental results supported the interaction effect predicted by the proposed model using free energy. Therefore, the negative free energy works as a mathematical index of SoA.

For products that are connected to the cloud, such as AI speakers, and whose functions and performance are expanding over time, their true value are found by exploring unknown functions instead of using only the functions that users are familiar with. Apter' s reversal theory proposed that there are two mental conditions of motivation, telic mode and paratelic mode. People in paratelic mode act to explore the purpose. In this study, we aim to formalize a mathematical model that can explain this paratelic mode, corresponding intrinsic motivation. We propose a unified model that can explain reversal theory and Berlyne’s optimal arousal level. The proposed unified model is mathematically formulated by applying the Bayesian information gain as an index of alertness. We analyze the model mathematically and vilified the predictions obtained using two AI speakers. The prediction of the proposed model was vilified by combining the results of our previous study and the results of the subjective evaluation of this study.

We are developing “Design Insights CAD” system that automatically checks the design rules on 3D-CAD and show the violation parts to prevent rework from manufacture and maintenance to design. This system has the following functions: 1) Shape recognition functions to search the target shape from 3D-CAD models, 2) Calculation functions to measure geometric features such as dimensions and angles. We combine these functions to generate digitalized rules that can be applied to a wide variety of design rules. This report describes the development of rules to evaluate the manufacturability of welding and casting and the results of their verification.

This is a position paper. It discusses what World we should establish after the World 1.0, which is an industrialized Society since the Industrial Revolution. The industrial Revolution brought us division of labor and we began to work for others. i.e., we started to work for external rewards. Although it satisfied our material needs, it is getting close to the ceiling, and many issues are emerging. One, typical in Japan, is decreasing workforce due to decreasing childbirth and aging society. Therefore, time is pressing for us to consider how we shift to the World 2.0. This paper discusses what world it would be best for World 2.0. The author insists that we have been focusing too much on material needs and on products. Therefore, it is time for us to turn our eyes and focus more on human needs. We should try to satisfy our psychological satisfaction and feeling of achievement. In short, we have been focusing too much on technological advancement, but we should focus our attention more on humans. To achieve this, it is emphasized that we should have a broader perspective to find our what we can do, with what we have, where we are. We should explore and expand the new horizon. Several illustrative examples are shown to demonstrate his argument.

It is pointed out that planning and development activities are very much different between US and Japan. In the US, start-ups sell their ideas to another company which is good at developing business. The start-ups, or planning companies, are expecting the company to develop a new market. Thus, planners and developers are separate, and they form a network. These market developing companies are excellent in risk management, and they can take a balance between risk and return. But in Japan, when it comes to risk management, Japanese are devoted only to reducing risks and they do not consider return associated with the risk. They pursue to develop a new market with their currently available resources. Thus, US style is network, while Japanese style is tree. Therefore, in Japanese design courses, we should try to open such a course, where engineering student studies together with business management, economics students, etc. Then, each local market can introduce Japanese way and develop their own market utilizing their own resources. This will lead local and Japanese companies to establish win-win relations.

This study aimed to verify whether there were linkages between“people who performed/non- performed as a doubt person in team exercises”and“individual Jung’s psychological types”．The subjects of this survey were 335 (265 men and 70 women，mean age±SD＝18.7±0.8 years）．Statistical tests (Fisher exact test，Residual analysis) were performed on them. The results suggested that there were certain linkage’s pattern between them under the condition of “not high enough situation of team psychological safety”．Firstly，there was a statistically significant linkage between “people who performed”and “extraversion” (p < .01), whereas there was a statistically significant linkage between “people who non-performed”and “introversion” (p < .01)．Secondly，there was a statistically significant linkage between“people who performed”and “extraversion and sensing” (p < .05), whereas there was a statistically significant linkage between“people who non-performed”and “introversion and sensing” (p < .05)．Thirdly，there was a statistically significant linkage between“people who performed”and “extraversion and thinking” (p < .05), whereas there was a statistically significant linkage between“people who non-performed”and “introversion and feeling” (p < .05)．While the results should be treated as a tentative, they can be used as a clue of preventing phenomena concerning “failure to indicate” in teams that challenge to achieve a goal through collaboration.

The present study proposes a level set based topology optimization method, which reduces the calculation costs using the adaptive mesh method. In this method, based on the adaptive mesh method, the calculation costs is reduced by deleting elements sets belonging to the void domain, which are necessary for stable numerical analysis but have little effect on the mechanical behavior of the structure, from the computational mesh of the finite element method. Elements removal is done by using the remeshing software, mmg2d. In addition, we will formulate a stable calculation as an alternative to the Ersatz material approach, which became unusable due to the removal of the void domain. The examples show the results of applying the method to rigidity maximization problems at linear elasticity and geometrically non-linear elasticity. In particular, the latter is expected to have the benefit of not only omitting calculation costs but also stabilizing numerical calculations. The proposed method enables efficient finite element analysis in optimization iterations.

This paper proposes a method to impose geometrical constraints for ensuring the visibility of the product user on optimal structures, with less computation time. In this scheme, we incorporate a visibility evaluation method based on fictitious physical models into topology optimization. First, a level set-based topology optimization method is briefly introduced. Then, fictitious physical models represented by a steady-state advection-diffusion equation is then built based on the geometrical requirements for the visibility. In this model, we consider material domains as virtual heat sources, and set the advection direction in the radial direction around a view point. The visibility is measured by the values of the fictitious physical model, because regions where the value of the fictitious physical field is high will represent the blind area. Furthermore, we focus on reducing the calculation time by improving the fictitious physical model. Next, an optimal problem is formulated based on the fictitious physical model. Finally, the validity and the utility of the proposed method is confirmed through numerical examples.

Topology optimization for cast parts considering parting surfaces design is one of the main challenge. This research presents a level-set based topology optimization method involving user-specified parting surfaces. In this research geometrical requirements for mold forming are fomulated using Partial Differential Equation for geometrial shape features. Numerical examples are offered to illustrate mold releasability of the design.

In this research, we propose a multi-scale design method of anisotropic acoustic metamaterials based on propagating direction determination. Anisotropic metamaterials are usually composed of periodic structures of unit cells. These periodic structures tend to induce local resonance, leading to a highly unusual macroscopic behavior. In previous works, design methods for anisotropic metamaterials comprised of only a single unit cell structure were proposed, which means that the macro-scale wave propagation properties which could be obtained are limited. Therefore, in this work, we propose a design method of acoustic metamaterials which is composed of several unit cell structures, to realize a complex wave propagation. To evaluate the macroscopic material property of periodic media, we first introduce the high-frequency homogenization (HFH) method. We also evaluate the macroscopic wave propagating direction derived from the HFH method, which is required to control the macro-scale wave propagation. We then design the micro-scale unit cells which exbibits the desired propagating direction, using the level-set based topology optimization method. The validity of the proposed method is verified through numerical examples.

This study proposes a new algorithm for a response-surface-assisted Reliability-Based Design Optimization (RBDO) method. RBDO is one of optimization techniques considering uncertainty and has gained attention in engineering field. Many studies have focused on response-surface-assisted RBDO methods since the number of function calls in RBDO is often larger than the deterministic optimization problem and the burden of the reliability analysis is huge. Especially, the sequential approximation optimization technique for RBDO problems has been studied actively. On the view of additional sampling strategies, these studies assumed that it is important to improve accuracy of reliability analysis. Therefore, sample distribution is often concentrated. However, it is preferable that the distribution is uniform because the global aspects of problems can be obtained. Additionally, few studies applied global search methods for optimization. In this study, an additional sampling strategy considering both improving accuracy of reliability analysis and searching the sparse region is developed. To utilize global search methods, the formulation in RBDO is converted into a deterministic formulation. Through two numerical examples, the validity of proposed method is discussed.

This paper deals with reliability-based design optimization of structures considering uncertainty in input distribution, where the structure is guaranteed, with the specified confidence level, to have the target reliability. A sufficient condition for this confidence-level constraint is given by using the principal component analysis and the order statistics applied to a given random samples of uncertain parameters. Concrete formulations of this approach are presented for the compliance optimization problem of trusses. The obtained optimization problem that conservatively approximates the original reliability-based design optimization problem with the specified confidence level is solved with a robust optimization approach.

Since its high compactness and heat transfer performance, plate-fin heat exchanger (PFHE) is widely used in the aspects of industry. For high productivity of industrial plants, it is important to determine the design of PFHE based on the requirements such as small core volume, high heat transfer rate and low pressure drop. In this paper, design optimization of PFHE for small core volume and high heat transfer rate is carried out. Seven parameters to determine the PFHE such as core width, core length, the number of fin layers, fin frequency and fin thickness are taken as design variables. Since high pressure drop results in high power consumption, pressure drop is handled as design constraint. Therefore, straight fin and perforated fin are considered for fin types. Sequential approximate optimization is adopted to optimize the design of PFHE in a small number of simulations. Through the result, the trade-off between the core volume and the heat transfer rate is clarified.

Magnesium alloys have biocompatibility and are suitable for weight reduction, so their application to medical devices is progressing. However, it is difficult to product design its optimum shape by magnesium, because magnesium is an HCP structural material and exhibits peculiar deformation behavior such as the SD effect. In this study, we performed a bending analysis for medical stent that introduced the SD effect for material model. Based on the results, topology optimization was performed and we considered how to design of magnesium stent which conditions where both compression and tension are present.

For machinery maintenance, there are more things to consider regarding disassembling operations than assembling ones. Therefore, disassembling machines is a difficult operation, and making a mistake in the disassembling process may cause damage to machines and the injury of operators. In order to avert these problems, parts list and operation manuals have been used. However, operation manuals don’t cover all parts, operators have to find the disassembly process by themselves. It’s a difficult task for unskilled operators. This study aims to develop a method for inference disassembling process to support unskilled operators. We introduce the positional relations matrix to find parts that prevent removal of a target part in disassembly direction. Moreover, multiple parts can be removed as a unit by considering connecting relations. This process is repeated until find the shortest steps for removing the target part. An algorithm was proposed by adopting these considerations. To verify the developed method a case study was conducted using the method, and it showed that the inferred process can help for disassembling by unskilled operators.