Takao Ito - Academia.edu (original) (raw)

Papers by Takao Ito

Proceedings of International Conference on Artificial Life and Robotics, Feb 9, 2023

Car sickness often occurs with dizziness and discomfort accompanied by vomiting and headaches las... more Car sickness often occurs with dizziness and discomfort accompanied by vomiting and headaches lasting several days in severely affected person. Car sickness has been studied from various standpoints on countermeasures and onset mechanisms, but a general measure has not been established yet. In this study, all dataset of the motion that occurs in the car and the head of the person sitting and/or driving in the car are collected based on data science. By validating the data, the characteristics of person who has experience of car sickness are tested. This study proposes a new measure aiming at development of motion sickness countermeasures that do not depend on car performance and find that the quick rotational motion of the head generated in the car could be considered as one of the factors that cause car sickness.

Proceedings of International Conference on Artificial Life and Robotics, 2022

Robot technology has been changed dramatically with massive development of internet environment. ... more Robot technology has been changed dramatically with massive development of internet environment. The author reviewed a plethora of literature and investigated advanced robot technologies. Today, most of typical robot technologies are used in single-cause-oriented products, such as robot vacuum cleaner and Asimo, a humanoid robot invented by Honda. These advanced products played important role in our modern society. For further development, a networking robot system with advanced technologies of internet and artificial intelligence is required to copy with the uncertainty in the future. Different technology should be combined and linked together for multiple-goal-oriented approach in the networking robot system. For evaluating the validity of our new system, a centrality index is introduced in this research.

Proceedings of International Conference on Artificial Life and Robotics, 2022

Michinoeki is considered as one of the most successful social experiments in Japan now. A plethor... more Michinoeki is considered as one of the most successful social experiments in Japan now. A plethora of literature of Michinoeki's have been published over past decades. The authors reviewed many important and typical literatures and found that the quantitative studies are still sparse. Obviously, it is a critical issue to measure the efficiency of Michinoeki's for its further development and revitalization of the local economy. Thus, the data of Michinoeki are gathered from all Michinoeki in Japan, and the relative efficiency are calculated using DEA model for comparison. Furthermore, the managerial implication of the results is discussed in this paper.

Proceedings of International Conference on Artificial Life and Robotics, 2022

Centrality is one of the most important indexes in network calculation. Based on the definition, ... more Centrality is one of the most important indexes in network calculation. Based on the definition, more than 400 different centrality such as degree, betweenness have been developed. All centrality indexes are calculated using the number of connection line, and its position in a given network. In automotive industry, keiretsu is considered as one of typical networks. It is crucial to measure the centrality of transaction network in the keiretsu. It is widely wellknown that different parts play different roles in assembly line. Thus, the importance of each connect line in a transaction network should be measured based upon the importance of the parts. A new parts-importance weighted centrality model is proposed in this paper.

2014 7th International Conference on Signal Processing, Image Processing and Pattern Recognition, 2014

This paper deals with the study of four-dimensional automata. Recently, due to the advances in ma... more This paper deals with the study of four-dimensional automata. Recently, due to the advances in many application areas such as dynamic image processing, computer animation, augmented reality (AR), and so on, it is useful for analyzing computation of four-dimensional information processing (three-dimensional pattern processing with time axis) to explicate the properties of four-dimensional automata. From this point of view, we have investigated many properties of four-dimensional automata and computational complexity. On the other hand, the class of sets accepted by probabilistic machines have been studied extensively. As far as we know, however, there is no results concerned with four-dimensional probabilistic machines. In this paper, we introduce four-dimensional probabilistic finite automata, and investigate some accepting powers of them.

This chapter elaborates network governance on the basis of information and influence. A network s... more This chapter elaborates network governance on the basis of information and influence. A network structure is defined in terms of boundaries and differentiation of interdependencies between firms. Two hypotheses allow examination of the relative role of relational versus hierarchical governance, through the mechanisms of information sharing versus influence respectively. In an empirical examination of the Keiretsu networks of Toyota and Mazda, we find a strong correlation between network centrality, measured as out-closeness, and firm profitability. This result suggests that influence proceeds mainly in the direction of share ownership and that these networks are hierarchical. The final sections of the chapter discuss the limitations of the research and future research.

Journal of Robotics, Networking and Artificial Life, 2014

This paper presents a four-dimensional computational model, k-neighborhood template A-type three-... more This paper presents a four-dimensional computational model, k-neighborhood template A-type three-dimensional bounded cellular acceptor (abbreviated as A-3BCA(k)), and discusses the hierarchical properties. An A-3BCA(k) is a four-dimensional automaton which consists of a pair of a converter and a configuration-reader. The former converts the given four-dimensional tape to the three-and two-dimensional configuration and the latter determines the acceptance or nonacceptance of given four-dimensional tape whether or not the derived two-dimensional configuration is accepted. We mainly investigate the difference of the accepting power based on the difference of the configuration-reader. It is shown that the difference of the accepting power of the configuration-reader tends to affect directly that of the A-3BCA(k) for the case when the converter is deterministic. On the other hand, results are not analogous for the nondeterministic case.

IEEE Access, 2020

This paper investigates vibration suppression of uncertain hose and drogue systems in the presenc... more This paper investigates vibration suppression of uncertain hose and drogue systems in the presence of actuator nonlinearities. Firstly, a previously presented model of the hose and drogue systems is extended to describe how the hose and drogue systems restrain the vibration, while the accompanying unknown aerodynamic coefficients are estimated by invoking the parameter projection method. Subsequently, for the actuator nonlinearities of dead-zone and saturation, a smooth dead-zone approximate function is constructed to design the dead-zone compensation method, based upon which the proposed control scheme can handle actuator dead-zone and saturation simultaneously while improving the output efficiency of the actuator. Next, for the actuator nonlinearities of backlash and saturation, a smooth backlash inverse is constructed based upon which the presented control scheme can cope with the both actuator nonlinearities simultaneously. Finally, by utilizing backstepping method and hyperbolic tangent function, the proposed control schemes can also achieve the control objectives of vibration suppression and external disturbance attenuation. Simulation examples are included to demonstrate the validity of the proposed control schemes.

International Journal of Education and …

Two typical different patterns of Information Systems (IS) outsourcing are considered as the most... more Two typical different patterns of Information Systems (IS) outsourcing are considered as the most effective approaches of business strategy. They are conventional outsourcing and quasi-outsourcing. The later generally is often adopted in large-scale organizations in Japan. In most such cases, an IS subsidiary is established by spinning off the firm's own information systems department. However, in recent years, most companies strengthen capital alliances relationship between their IS subsidiary and external vendors, while some companies sell their IS subsidiary for separating it completely from their parent company. On the other hand, there is growing diversification in the arrangement/management of IS subsidiaries. For instance, some firms force their IS subsidiary to withdraw from external sales business while other firms go further and integrate their IS subsidiary back into their parent company again (i.e., backsourcing). This research employs case study in order to investigate the determinant factors which have strong effect on these IS subsidiary arrangements. In this paper, we first review relevant previous studies on IS outsourcing. And then we introduce case studies of two chemical manufacturing companies in Japan and discuss its implications. Finally, we propose some propositions based on the implications derived from the case studies. This paper therefore provides an empirical perspective of the IS outsourcing in Japan.

Journal of Robotics, Networking and Artificial Life, 2014

Just as workflow and transactional linkages, inter-firm capital relationships are similarly known... more Just as workflow and transactional linkages, inter-firm capital relationships are similarly known to have an impact on corporate performance. Because of the superior performance of Japanese networks known as Keiretsu, many companies have begun to recognize the importance of capital linkages whereas other companies have placed emphasis on improving coordination of managerial resources. In this paper, we review the literature on network organizations with a lens focused on examining the capital relationships in Yokokai, the Mazda's Keiretsu. Employing regression analysis, three significant indices, influence, degree, and efficiency, were selected from nine indices, including others that include dyadic redundancy, dyadic constraint, effective size, constraint, hierarchy, and density. We propose a new approach, called IDE spatial model, to calculate the strength of the inter-firm's relationships. In order to ascertain the rational inter-firm relationships, network indices and corporate performance are analyzed. Therefore, this research suggests a new perspective to examine the rational inter-firm relationship that can be used in any network organization.

International Journal of Information Systems and Project Management, 2018

The purpose of this paper is an analysis of survival in the Japanese information service industry... more The purpose of this paper is an analysis of survival in the Japanese information service industry. Information service firms are generally classified into two typical patterns. One is the group of independent firms such as software vendors, and the other is the group of non-independent such as subsidiaries established by spinning off and so on. We used a sample of 334 firms in Japan and analyzed by Kaplan-Meier estimator method and Cox proportional hazard regression model in order to investigate the difference of survival between these two groups and/or among other attributes. As a result, the lifespan of the information service firms significantly depends on the degree of system integration sales ratio, software development sales ratio, and entrusted processing sales ratio. On the contrary, property of non-independence and high sales ratio with main customers have a negative influence on their survival rates, i.e. lifespan. The paper discusses these results and offers some manageri...

Two typical but different types of organization exist: one is traditional organization with a pyr... more Two typical but different types of organization exist: one is traditional organization with a pyramid shaped hierarchical structure, while the other is a network organization with a non-hierarchical structure. In the organization sciences and its allied field including business administration, economics, public administration , sociology, and psychology, the behavioral patterns and values required in a specific organization have been discussed from the standpoint of being successful relative to other competing firms. From the examination of the literature, it is readily discernible that organizational studies on authority and layering have primarily been qualitative in nature. Organization theory suggests that to streamline the management of a large organization begins by dividing it into several sections. We propose a new mathematical model which defines internal and external contributions for the organizations in this paper. Consequently, the evaluation function in the new model i...

WSEAS Transactions on Computers archive, 2010

The recent advances in computer animation, motion image processing, robotics and so on prompted u... more The recent advances in computer animation, motion image processing, robotics and so on prompted us to analyze computational complexity of four-dimensional pattern processing. Thus, the research of four-dimensional automata as a computational model of four-dimensional pattern processing has also been meaningful. From this viewpoint, we introduced a four-dimensional alternating Turing machine (4-ATM) operating in parallel. In this paper, we continue the investigations about 4-ATM's, deal with a four-dimensional synchronized alternating Turing machine (4-SATM), and investigate some properties of 4-SATM's which each sidelength of each input tape is equivalent. The main topics of this paper are: (1) hierarchies based on the number of processes of 4-SATM's, and (2) recognizability of connected pictures by 4-SATM's.

The recent advances in computer animation, motion image processing, robotics and so on prompted u... more The recent advances in computer animation, motion image processing, robotics and so on prompted us to analyze computational complexity of four-dimensional pattern processing. Thus, the research of four-dimensional automata as a computational model of four-dimensional pattern processing has also been meaningful. From this viewpoint, we introduced a four-dimensional alternating Turing machine (4-ATM) operating in parallel. In this paper, we continue the investigations about 4-ATM's, deal with a four-dimensional synchronized alternating Turing machine (4-SATM), and investigate some properties of 4-SATM's which each sidelength of each input tape is equivalent. The main topics of this paper are: (1) hierarchies based on the number of processes of 4-SATM's, and (2) recognizability of connected pictures by 4-SATM's.

Synchronized alternating machine is an alternating machine with a special subset of internal stat... more Synchronized alternating machine is an alternating machine with a special subset of internal states called synchronizing states. This paper introduces a four-dimensional synchronized alternating Turing machine (4-SATM), and investigates fundamental properties of 4-SATM's. The main topics of this paper are: (1) a relationship between the accepting powers of 4-SATM's and four-dimensional alternating Turing machines with small space bounds, (2) a relationship between the accepting powers of seven-way and eight-way 4-SATM's, (3) a relationship between the accepting powers of 4-SATM's and four-dimensional nondeterministic Turing machines. In this paper, we let each sidelength of each input tape of these automata be equivalent in order to increase the theoretical interest.

Journal of Robotics, Networking and Artificial Life, 2020

Proceedings of International Conference on Artificial Life and Robotics, 2017

In 1993, mathematician Feinstein found out perfect play on 6×6 board Othello gives 16-20 loss for... more In 1993, mathematician Feinstein found out perfect play on 6×6 board Othello gives 16-20 loss for the first player by using computer. He reported on the Web that it took two weeks to search forty billion positions in order to obtain the result. In our previous papers, we confirmed the perfect play he found is correct. And we also found another perfect play different from the one he found to search 884 billion positions. In order to search efficiently, we attempted to reduce the search space to find some perfect play. In this paper, we introduce some techniques to solve 6×6 board Othello by searching about nine billion positions.

Proceedings of International Conference on Artificial Life and Robotics, 2018

In response to the constant increase in population and tourism worldwide, there is a need for the... more In response to the constant increase in population and tourism worldwide, there is a need for the development of cross-language market research tools that are more cost and time effective than surveys or interviews. Focusing on the Chinese tourism boom and the hotel industry in Japan, we extracted the most influential keywords in emotional judgement from Chinese online reviews of Japanese hotels in the portal site Ctrip. Using an entropy based mathematical model and a machine learning algorithm, we determined the words that most closely represent the demands and emotions of this customer base.

Journal of Robotics, Networking and Artificial Life, 2014

Although two major Japanese manufacturers, Toyota and Mazda, compete in the automotive market, th... more Although two major Japanese manufacturers, Toyota and Mazda, compete in the automotive market, their corporate performance, respectively, is different because the internal resources and the way they coordinate interrelationships among their network partners is known to be divergent. Both these two companies have their own collaborating organizations, Kyohokai for Toyota and Yokokai for Mazda. Kyohokai, in contrast to Yokokai, is a central-oriented organization with strong interactive cooperation among network partners. Consistent with the stream of research on the coordination of internal resources and external inter-firm relationships, the purpose of this research is to identify and contrast the best practices of Toyota to Mazda using a comparative approach. This paper reviews relevant lliterature on network organizations to focus on the differences between Kyohokai and Yokokai. Specifically, it makes a contribution by proposing a new perspective to identify the determinants of corporate performance and clarify the difference among the external inter-firm's relationships between Kyohokai and Yokokai, thus ascertaining the rational structure of network organizations.

Phytopathology, 2002

Sequential polyacrylamide gel electrophoresis analyses showed many viroid-like RNAs in samples co... more Sequential polyacrylamide gel electrophoresis analyses showed many viroid-like RNAs in samples collected from citrus trees in Japan. Reverse transcription polymerase chain reaction and sequencing analyses of the amplified fragments verified that they were derived from variants of six citrus viroids, Citrus exocortis viroid (CEVd), Citrus bent leaf viroid (CBLVd) including CVd-I-LSS (a distinct variant of CBLVd), Hop stunt viroid, Citrus viroid III, Citrus viroid IV, and Citrus viroid OS. The samples induced symptoms with variable severity in Arizona 861-S1 ‘Etrog’ citrons (Citrus medica L.) likely due to the varying accumulation patterns produced by the different viroids. Some of the symptoms caused by the samples harboring the citrus viroids other than CEVd were as severe as those caused by CEVd. Some source citrus trees showing the severe bark scaling characteristic of exocortis disease in trifoliate orange (Poncirus trifoliata (L.) Raf.) rootstocks contained only citrus viroids o...

Proceedings of International Conference on Artificial Life and Robotics, Feb 9, 2023

Car sickness often occurs with dizziness and discomfort accompanied by vomiting and headaches las... more Car sickness often occurs with dizziness and discomfort accompanied by vomiting and headaches lasting several days in severely affected person. Car sickness has been studied from various standpoints on countermeasures and onset mechanisms, but a general measure has not been established yet. In this study, all dataset of the motion that occurs in the car and the head of the person sitting and/or driving in the car are collected based on data science. By validating the data, the characteristics of person who has experience of car sickness are tested. This study proposes a new measure aiming at development of motion sickness countermeasures that do not depend on car performance and find that the quick rotational motion of the head generated in the car could be considered as one of the factors that cause car sickness.

Proceedings of International Conference on Artificial Life and Robotics, 2022

Robot technology has been changed dramatically with massive development of internet environment. ... more Robot technology has been changed dramatically with massive development of internet environment. The author reviewed a plethora of literature and investigated advanced robot technologies. Today, most of typical robot technologies are used in single-cause-oriented products, such as robot vacuum cleaner and Asimo, a humanoid robot invented by Honda. These advanced products played important role in our modern society. For further development, a networking robot system with advanced technologies of internet and artificial intelligence is required to copy with the uncertainty in the future. Different technology should be combined and linked together for multiple-goal-oriented approach in the networking robot system. For evaluating the validity of our new system, a centrality index is introduced in this research.

Proceedings of International Conference on Artificial Life and Robotics, 2022

Michinoeki is considered as one of the most successful social experiments in Japan now. A plethor... more Michinoeki is considered as one of the most successful social experiments in Japan now. A plethora of literature of Michinoeki's have been published over past decades. The authors reviewed many important and typical literatures and found that the quantitative studies are still sparse. Obviously, it is a critical issue to measure the efficiency of Michinoeki's for its further development and revitalization of the local economy. Thus, the data of Michinoeki are gathered from all Michinoeki in Japan, and the relative efficiency are calculated using DEA model for comparison. Furthermore, the managerial implication of the results is discussed in this paper.

Proceedings of International Conference on Artificial Life and Robotics, 2022

Centrality is one of the most important indexes in network calculation. Based on the definition, ... more Centrality is one of the most important indexes in network calculation. Based on the definition, more than 400 different centrality such as degree, betweenness have been developed. All centrality indexes are calculated using the number of connection line, and its position in a given network. In automotive industry, keiretsu is considered as one of typical networks. It is crucial to measure the centrality of transaction network in the keiretsu. It is widely wellknown that different parts play different roles in assembly line. Thus, the importance of each connect line in a transaction network should be measured based upon the importance of the parts. A new parts-importance weighted centrality model is proposed in this paper.

2014 7th International Conference on Signal Processing, Image Processing and Pattern Recognition, 2014

This paper deals with the study of four-dimensional automata. Recently, due to the advances in ma... more This paper deals with the study of four-dimensional automata. Recently, due to the advances in many application areas such as dynamic image processing, computer animation, augmented reality (AR), and so on, it is useful for analyzing computation of four-dimensional information processing (three-dimensional pattern processing with time axis) to explicate the properties of four-dimensional automata. From this point of view, we have investigated many properties of four-dimensional automata and computational complexity. On the other hand, the class of sets accepted by probabilistic machines have been studied extensively. As far as we know, however, there is no results concerned with four-dimensional probabilistic machines. In this paper, we introduce four-dimensional probabilistic finite automata, and investigate some accepting powers of them.

This chapter elaborates network governance on the basis of information and influence. A network s... more This chapter elaborates network governance on the basis of information and influence. A network structure is defined in terms of boundaries and differentiation of interdependencies between firms. Two hypotheses allow examination of the relative role of relational versus hierarchical governance, through the mechanisms of information sharing versus influence respectively. In an empirical examination of the Keiretsu networks of Toyota and Mazda, we find a strong correlation between network centrality, measured as out-closeness, and firm profitability. This result suggests that influence proceeds mainly in the direction of share ownership and that these networks are hierarchical. The final sections of the chapter discuss the limitations of the research and future research.

Journal of Robotics, Networking and Artificial Life, 2014

This paper presents a four-dimensional computational model, k-neighborhood template A-type three-... more This paper presents a four-dimensional computational model, k-neighborhood template A-type three-dimensional bounded cellular acceptor (abbreviated as A-3BCA(k)), and discusses the hierarchical properties. An A-3BCA(k) is a four-dimensional automaton which consists of a pair of a converter and a configuration-reader. The former converts the given four-dimensional tape to the three-and two-dimensional configuration and the latter determines the acceptance or nonacceptance of given four-dimensional tape whether or not the derived two-dimensional configuration is accepted. We mainly investigate the difference of the accepting power based on the difference of the configuration-reader. It is shown that the difference of the accepting power of the configuration-reader tends to affect directly that of the A-3BCA(k) for the case when the converter is deterministic. On the other hand, results are not analogous for the nondeterministic case.

IEEE Access, 2020

This paper investigates vibration suppression of uncertain hose and drogue systems in the presenc... more This paper investigates vibration suppression of uncertain hose and drogue systems in the presence of actuator nonlinearities. Firstly, a previously presented model of the hose and drogue systems is extended to describe how the hose and drogue systems restrain the vibration, while the accompanying unknown aerodynamic coefficients are estimated by invoking the parameter projection method. Subsequently, for the actuator nonlinearities of dead-zone and saturation, a smooth dead-zone approximate function is constructed to design the dead-zone compensation method, based upon which the proposed control scheme can handle actuator dead-zone and saturation simultaneously while improving the output efficiency of the actuator. Next, for the actuator nonlinearities of backlash and saturation, a smooth backlash inverse is constructed based upon which the presented control scheme can cope with the both actuator nonlinearities simultaneously. Finally, by utilizing backstepping method and hyperbolic tangent function, the proposed control schemes can also achieve the control objectives of vibration suppression and external disturbance attenuation. Simulation examples are included to demonstrate the validity of the proposed control schemes.

International Journal of Education and …

Two typical different patterns of Information Systems (IS) outsourcing are considered as the most... more Two typical different patterns of Information Systems (IS) outsourcing are considered as the most effective approaches of business strategy. They are conventional outsourcing and quasi-outsourcing. The later generally is often adopted in large-scale organizations in Japan. In most such cases, an IS subsidiary is established by spinning off the firm's own information systems department. However, in recent years, most companies strengthen capital alliances relationship between their IS subsidiary and external vendors, while some companies sell their IS subsidiary for separating it completely from their parent company. On the other hand, there is growing diversification in the arrangement/management of IS subsidiaries. For instance, some firms force their IS subsidiary to withdraw from external sales business while other firms go further and integrate their IS subsidiary back into their parent company again (i.e., backsourcing). This research employs case study in order to investigate the determinant factors which have strong effect on these IS subsidiary arrangements. In this paper, we first review relevant previous studies on IS outsourcing. And then we introduce case studies of two chemical manufacturing companies in Japan and discuss its implications. Finally, we propose some propositions based on the implications derived from the case studies. This paper therefore provides an empirical perspective of the IS outsourcing in Japan.

Journal of Robotics, Networking and Artificial Life, 2014

Just as workflow and transactional linkages, inter-firm capital relationships are similarly known... more Just as workflow and transactional linkages, inter-firm capital relationships are similarly known to have an impact on corporate performance. Because of the superior performance of Japanese networks known as Keiretsu, many companies have begun to recognize the importance of capital linkages whereas other companies have placed emphasis on improving coordination of managerial resources. In this paper, we review the literature on network organizations with a lens focused on examining the capital relationships in Yokokai, the Mazda's Keiretsu. Employing regression analysis, three significant indices, influence, degree, and efficiency, were selected from nine indices, including others that include dyadic redundancy, dyadic constraint, effective size, constraint, hierarchy, and density. We propose a new approach, called IDE spatial model, to calculate the strength of the inter-firm's relationships. In order to ascertain the rational inter-firm relationships, network indices and corporate performance are analyzed. Therefore, this research suggests a new perspective to examine the rational inter-firm relationship that can be used in any network organization.

International Journal of Information Systems and Project Management, 2018

The purpose of this paper is an analysis of survival in the Japanese information service industry... more The purpose of this paper is an analysis of survival in the Japanese information service industry. Information service firms are generally classified into two typical patterns. One is the group of independent firms such as software vendors, and the other is the group of non-independent such as subsidiaries established by spinning off and so on. We used a sample of 334 firms in Japan and analyzed by Kaplan-Meier estimator method and Cox proportional hazard regression model in order to investigate the difference of survival between these two groups and/or among other attributes. As a result, the lifespan of the information service firms significantly depends on the degree of system integration sales ratio, software development sales ratio, and entrusted processing sales ratio. On the contrary, property of non-independence and high sales ratio with main customers have a negative influence on their survival rates, i.e. lifespan. The paper discusses these results and offers some manageri...

Two typical but different types of organization exist: one is traditional organization with a pyr... more Two typical but different types of organization exist: one is traditional organization with a pyramid shaped hierarchical structure, while the other is a network organization with a non-hierarchical structure. In the organization sciences and its allied field including business administration, economics, public administration , sociology, and psychology, the behavioral patterns and values required in a specific organization have been discussed from the standpoint of being successful relative to other competing firms. From the examination of the literature, it is readily discernible that organizational studies on authority and layering have primarily been qualitative in nature. Organization theory suggests that to streamline the management of a large organization begins by dividing it into several sections. We propose a new mathematical model which defines internal and external contributions for the organizations in this paper. Consequently, the evaluation function in the new model i...

WSEAS Transactions on Computers archive, 2010

The recent advances in computer animation, motion image processing, robotics and so on prompted u... more The recent advances in computer animation, motion image processing, robotics and so on prompted us to analyze computational complexity of four-dimensional pattern processing. Thus, the research of four-dimensional automata as a computational model of four-dimensional pattern processing has also been meaningful. From this viewpoint, we introduced a four-dimensional alternating Turing machine (4-ATM) operating in parallel. In this paper, we continue the investigations about 4-ATM's, deal with a four-dimensional synchronized alternating Turing machine (4-SATM), and investigate some properties of 4-SATM's which each sidelength of each input tape is equivalent. The main topics of this paper are: (1) hierarchies based on the number of processes of 4-SATM's, and (2) recognizability of connected pictures by 4-SATM's.

The recent advances in computer animation, motion image processing, robotics and so on prompted u... more The recent advances in computer animation, motion image processing, robotics and so on prompted us to analyze computational complexity of four-dimensional pattern processing. Thus, the research of four-dimensional automata as a computational model of four-dimensional pattern processing has also been meaningful. From this viewpoint, we introduced a four-dimensional alternating Turing machine (4-ATM) operating in parallel. In this paper, we continue the investigations about 4-ATM's, deal with a four-dimensional synchronized alternating Turing machine (4-SATM), and investigate some properties of 4-SATM's which each sidelength of each input tape is equivalent. The main topics of this paper are: (1) hierarchies based on the number of processes of 4-SATM's, and (2) recognizability of connected pictures by 4-SATM's.

Synchronized alternating machine is an alternating machine with a special subset of internal stat... more Synchronized alternating machine is an alternating machine with a special subset of internal states called synchronizing states. This paper introduces a four-dimensional synchronized alternating Turing machine (4-SATM), and investigates fundamental properties of 4-SATM's. The main topics of this paper are: (1) a relationship between the accepting powers of 4-SATM's and four-dimensional alternating Turing machines with small space bounds, (2) a relationship between the accepting powers of seven-way and eight-way 4-SATM's, (3) a relationship between the accepting powers of 4-SATM's and four-dimensional nondeterministic Turing machines. In this paper, we let each sidelength of each input tape of these automata be equivalent in order to increase the theoretical interest.

Journal of Robotics, Networking and Artificial Life, 2020

Proceedings of International Conference on Artificial Life and Robotics, 2017

In 1993, mathematician Feinstein found out perfect play on 6×6 board Othello gives 16-20 loss for... more In 1993, mathematician Feinstein found out perfect play on 6×6 board Othello gives 16-20 loss for the first player by using computer. He reported on the Web that it took two weeks to search forty billion positions in order to obtain the result. In our previous papers, we confirmed the perfect play he found is correct. And we also found another perfect play different from the one he found to search 884 billion positions. In order to search efficiently, we attempted to reduce the search space to find some perfect play. In this paper, we introduce some techniques to solve 6×6 board Othello by searching about nine billion positions.

Proceedings of International Conference on Artificial Life and Robotics, 2018

In response to the constant increase in population and tourism worldwide, there is a need for the... more In response to the constant increase in population and tourism worldwide, there is a need for the development of cross-language market research tools that are more cost and time effective than surveys or interviews. Focusing on the Chinese tourism boom and the hotel industry in Japan, we extracted the most influential keywords in emotional judgement from Chinese online reviews of Japanese hotels in the portal site Ctrip. Using an entropy based mathematical model and a machine learning algorithm, we determined the words that most closely represent the demands and emotions of this customer base.

Journal of Robotics, Networking and Artificial Life, 2014

Although two major Japanese manufacturers, Toyota and Mazda, compete in the automotive market, th... more Although two major Japanese manufacturers, Toyota and Mazda, compete in the automotive market, their corporate performance, respectively, is different because the internal resources and the way they coordinate interrelationships among their network partners is known to be divergent. Both these two companies have their own collaborating organizations, Kyohokai for Toyota and Yokokai for Mazda. Kyohokai, in contrast to Yokokai, is a central-oriented organization with strong interactive cooperation among network partners. Consistent with the stream of research on the coordination of internal resources and external inter-firm relationships, the purpose of this research is to identify and contrast the best practices of Toyota to Mazda using a comparative approach. This paper reviews relevant lliterature on network organizations to focus on the differences between Kyohokai and Yokokai. Specifically, it makes a contribution by proposing a new perspective to identify the determinants of corporate performance and clarify the difference among the external inter-firm's relationships between Kyohokai and Yokokai, thus ascertaining the rational structure of network organizations.

Phytopathology, 2002

Sequential polyacrylamide gel electrophoresis analyses showed many viroid-like RNAs in samples co... more Sequential polyacrylamide gel electrophoresis analyses showed many viroid-like RNAs in samples collected from citrus trees in Japan. Reverse transcription polymerase chain reaction and sequencing analyses of the amplified fragments verified that they were derived from variants of six citrus viroids, Citrus exocortis viroid (CEVd), Citrus bent leaf viroid (CBLVd) including CVd-I-LSS (a distinct variant of CBLVd), Hop stunt viroid, Citrus viroid III, Citrus viroid IV, and Citrus viroid OS. The samples induced symptoms with variable severity in Arizona 861-S1 ‘Etrog’ citrons (Citrus medica L.) likely due to the varying accumulation patterns produced by the different viroids. Some of the symptoms caused by the samples harboring the citrus viroids other than CEVd were as severe as those caused by CEVd. Some source citrus trees showing the severe bark scaling characteristic of exocortis disease in trifoliate orange (Poncirus trifoliata (L.) Raf.) rootstocks contained only citrus viroids o...