著者

Yumeta Seki Yu Kuwajima Hiroki Shigemune Yuhei Yamada Shingo Maeda

出版者

Fuji Technology Press Ltd.

雑誌

Journal of Robotics and Mechatronics (ISSN:09153942)

巻号頁・発行日

vol.32, no.5, pp.939-946, 2020-10-20 (Released:2020-10-20)

参考文献数

29

被引用文献数

19

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Soft robots have great potential to realize machines that interact and coexist with humans. A key technology to realize soft robots is soft fluidic actuators. Previously, we developed a soft pump using the electrohydrodynamics (EHD) phenomenon. EHD is a flow phenomenon, which is generated by applying a high voltage to a dielectric fluid. In this study, we developed flexible high-power-density EHD pumps. First, a pump was fabricated by a simple design with interdigitated electrodes. Second, a mathematical model was used to analyze the pressure generated per length assuming that electric fields only act between neighboring electrodes in a flexible EHD pump with interdigitated electrodes. The results were used to optimize the gap between electrodes to maximize the pressure per length. Third, we used the optimized process to fabricate multiple flexible EHD pumps. The procedure produced pumps easily and reliably. Fourth, we compared the experimental values with the analytical solutions. The good agreement confirmed that the generated pressure per unit length can be approximated in a uniform electric field between neighboring electrodes. Because our flexible EHD pump can operate even when deformed, it has potential for wearable device applications.

著者

Jeffrey S. Perez Hiroyuki Tsutsumi Mabelline T. Cahulogan Desiderio P. Cabanlit Ma. Isabel T. Abigania Takashi Nakata

出版者

Fuji Technology Press Ltd.

雑誌

Journal of Disaster Research (ISSN:18812473)

巻号頁・発行日

vol.10, no.1, pp.74-82, 2015-02-01 (Released:2019-07-01)

参考文献数

35

被引用文献数

7

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The 1,250-km-long, NNW-trending, arc-parallel Philippine fault, one of the world’s most active tectonic structures, traverses the Philippine archipelago and has been the source of surface-rupturing earthquakes during the last four centuries. In this paper, we will discuss Philippine fault distribution and segmentation in Mindanao Island by integrating detailed fault mapping together with new geological and paleoseismic data and the analysis of historical surface-rupturing earthquakes. Using geometric segmentation criteria, we have identified nine geometric segments separated by discontinuities such as en echelon steps, bends, changes in strike, gaps, steps and bifurcation in the surface trace. Fault segments ranges from 20 to 100 km in length and are capable of generating earthquakes of Mw6.6 to Mw7.4. The results of our study have important implications for earthquake generation potential and seismic hazard assessment of the Philippine fault in Mindanao Island.

著者

Masashi Nagai Setsuya Nakada

出版者

Fuji Technology Press Ltd.

雑誌

Journal of Disaster Research (ISSN:18812473)

巻号頁・発行日

vol.17, no.5, pp.829-838, 2022-08-01 (Released:2022-08-01)

参考文献数

30

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A hydrovolcanic eruption in the early hours of October 8, 2016 triggered a power outage of about 29,000 houses (∼50,000 habitants) in the Aso caldera area, Kyushu, Japan. Although it was recovered naturally by the early morning of that day, the power outage occurred again in the evening following rainfall that began in the afternoon. The power supply in the caldera area had been temporarily maintained despite the heavy landslide damage due to strong earthquakes in April 2016, without the supplemental transmission lines for the normal standard. The power outage is considered to have been due to the insulator flashover in the power substation, Ichinomiya, Aso, around which the mass of volcanic ash was about 3,000 g/m2 or less (≤3 mm thick). This outage resulted from high electric conductivity of the volcanic ash that was wetted with strongly acidic water dammed in the crater before the eruption. This may be one example of the power outage incident due to thin ash fall.

著者

Hiroshi Inoue Zhengying Fan Melchor Lasala Robert Tiglao Bartolome Bautista Debbie Rivera Ishmael Narag

出版者

Fuji Technology Press Ltd.

雑誌

Journal of Disaster Research (ISSN:18812473)

巻号頁・発行日

vol.10, no.1, pp.35-42, 2015-02-01 (Released:2019-07-01)

参考文献数

10

被引用文献数

3

---

We designed a seismic intensity meter and a data collection network for use in the Philippines. The station unit deployed consists of a digital acceleration sensor with 0.1 gal noise and a compact Microsoft Windows PC. The station unit, which is designed to be installed in local government offices, calculates values every 10 seconds for the PEIS (Philippine Earthquake Intensity Scale), and these values are shown on a display and transmitted to the main PHIVOLCS office over the Internet. One hundred units to be deployed throughout the country are now being distributed to offices.

著者

Gengwang Liu Yue Yang Wanting Mo Wentao Gu Rihan Wang

出版者

Fuji Technology Press Ltd.

雑誌

Journal of Advanced Computational Intelligence and Intelligent Informatics (ISSN:13430130)

巻号頁・発行日

vol.27, no.5, pp.771-779, 2023-09-20 (Released:2023-09-21)

参考文献数

21

---

The private placement of A-shares gained momentum with the release of the Administrative Measures for Securities Issuance of Listed Companies in 2006. This led to enhanced research on the impact of private placement on stock prices. In 2012, the Chinese government relaxed the requirements for directed issuance of listed companies, resulting in a surge of directed issuance since then. This study uses a sample of listed companies that conducted private placements in the A-share market between 2013 and 2021, to analyze the impact of investor sentiment on stock price differences after private placements from the perspective of short and long-term excess returns. This study constructs the non-main investor sentiment of individual stocks using high-frequency tick data of individual stocks and explores the relationship between this stock price anomaly and investor sentiment using multiple regression analysis. The results show a positive short-term announcement effect of A-share private placements, with the excess return rate occurring mainly before the plan announcement date. The stock price difference from the plan announcement date to ten trading days thereafter has a significantly negative relationship with the excess return rate. Furthermore, investor sentiment in private placements may negatively affect long-term stock performance. This study suggests that this phenomenon is caused by higher investor sentiment pushing stock prices upward in the short term, causing them to deviate from fundamentals, creating mispricing, and then driving them back to fundamentals, with information disclosure. After controlling for the severity of information disclosure, the effect of investor sentiment on long-term stock price performance becomes insignificant.

著者

Siti Nurul Fitriah Mohamad Roslan Hasni Florentin Smarandache

出版者

Fuji Technology Press Ltd.

雑誌

Journal of Advanced Computational Intelligence and Intelligent Informatics (ISSN:13430130)

巻号頁・発行日

vol.27, no.5, pp.837-847, 2023-09-20 (Released:2023-09-21)

参考文献数

50

---

In graph theory, the concept of domination is essential in a variety of domains. It has broad applications in diverse fields such as coding theory, computer network models, and school bus routing and facility location problems. If a fuzzy graph fails to obtain acceptable results, neutrosophic sets and neutrosophic graphs can be used to model uncertainty correlated with indeterminate and inconsistent information in arbitrary real-world scenario. In this study, we consider the concept of domination as it relates to single-valued neutrosophic incidence graphs (SVNIGs). Given the importance of domination and its utilization in numerous fields, we propose the application of dominating sets in SVNIG with valid edges. We present some relevant definitions such as those of valid edges, cardinality, and isolated vertices in SVNIG along with some examples. Furthermore, we also show a few significant sets connected to the dominating set in an SVNIG such as independent and irredundant sets. We also investigate a relationship between the concepts of dominating sets and domination numbers as well as irredundant and independence sets in SVNIGs. Finally, a real-life deployment of domination in SVNIGs is investigated in relation to COVID-19 vaccination locations as a practical application.

著者

Namiko Sakurai Koyuru Iwanami Shingo Shimizu Yasushi Uji Shin-ichi Suzuki Takeshi Maesaka Ken-ichi Shimose Paul R. Krehbiel William Rison Daniel Rodeheffer

出版者

Fuji Technology Press Ltd.

雑誌

Journal of Disaster Research (ISSN:18812473)

巻号頁・発行日

vol.16, no.4, pp.778-785, 2021-06-01 (Released:2021-06-01)

参考文献数

26

被引用文献数

3

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The National Research Institute for Earth Science and Disaster Resilience deployed a lightning mapping array (LMA) in the Tokyo metropolitan area in March 2017. Called the “Tokyo LMA,” it obtains detailed three-dimensional observations of the total lightning activity (cloud-to-ground and intracloud flashes) in storms. The network initially consisted of 8 receiving stations, expanded to 12 stations in March 2018. Real-time total lightning images were first opened on the webpage in Japan. Real-time observations from the Tokyo LMA will be used in nowcasting lightning hazards and mitigating lightning disasters. Archived data will be used to develop lightning prediction techniques and a lightning climatology for the Tokyo metropolitan area.

著者

Seo Takeda Tomohiro Umetani

出版者

Fuji Technology Press Ltd.

雑誌

Journal of Robotics and Mechatronics (ISSN:09153942)

巻号頁・発行日

vol.35, no.2, pp.380-386, 2023-04-20 (Released:2023-04-20)

参考文献数

19

被引用文献数

1

---

This study proposes a method for estimating the initial position of a mobile robot during a mobile robot experiment using expansion resetting. Depending on the type of sensor attached to the robot and the robot position and orientation estimation method, many operations may be required to estimate the initial position of the robot during an experimental run. The proposed method reduces the time and manual operations required to estimate the initial position and orientation of a mobile robot. The implementation of the method and its experimental results demonstrated the feasibility and effectiveness of the procedure.

著者

Mikio Ishiwatari Daniel P. Aldrich Daisuke Sasaki

出版者

Fuji Technology Press Ltd.

雑誌

Journal of Disaster Research (ISSN:18812473)

巻号頁・発行日

vol.18, no.5, pp.467-474, 2023-08-01 (Released:2023-08-01)

参考文献数

43

被引用文献数

1

---

Whether national and local governments should assume larger financial responsibility for reducing disaster risk remains a controversial issue. Local governments lack resources to cover the full cost of managing mega-disasters and need assistance from higher level governments. However, national governments covering all costs may create moral hazards, discouraging local governments from investing in ex-ante measures. This study identifies national and local governments’ fiscal responsibility determinants for disaster management. Despite the differences between the federal system in the US and the centralized system in Japan, the two countries’ national governments share common practices. Both have continuously developed legislation to expand their financial responsibilities for relief and recovery efforts as disaster consequences have increased. We argue that despite major institutional differences in Japan’s unitary and the US federal government systems, both have expanded the areas covered by national assistance along with the amount over time. These findings bring with them recommendations for governments in an era of increasing extreme weather events due to climate change.

著者

Tetsuya Nakamura Satoru Masuda Akifumi Kuchiki Atsushi Maruyama

出版者

Fuji Technology Press Ltd.

雑誌

Journal of Disaster Research (ISSN:18812473)

巻号頁・発行日

vol.15, no.7, pp.991-1010, 2020-12-01 (Released:2020-12-01)

参考文献数

41

被引用文献数

3

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In this article, we analyzed the effects of radioactive contamination from the Semipalatinsk nuclear test site on food choices in Kazakhstan. Nearly 90% of citizens in Kazakhstan knew their health had been affected by radioactive material from the nuclear test site, with more than 50% of citizens still confirming the safety of foodstuffs regarding radioactive materials when purchasing food. However, citizens in the vicinity of the nuclear test site did not take countermeasures against internal exposure due to declining fear of radioactivity, despite refraining from purchasing food from near the nuclear test site. More than 80% of Kazakhstan understood that exposure to radioactive materials was both external and internal. Further, Kazakhs were more aware of the effects of internal exposure on the human body than either Ukrainians or Japanese. Elderly people who remembered the times when nuclear tests had been conducted were aware of radioactive materials in food. High-income individuals took measures to control radioactive contamination in consideration of their nutritional balance, while low-income individuals refrained from purchasing food from near the nuclear test site as a means of controlling potential contamination. In Kazakhstan, more than 60% of citizens did not take measures against internal exposure, but the number of citizens who were concerned about radioactive materials was much higher than in either Ukraine or Japan. In Kazakhstan, 30–40% of citizens, particularly women, would buy at least 20% more if foodstuffs with lower than the regulated level of radioactive materials were sold.

著者

Meng Zhou Zihao Wang Jing Wang Zhe Dong

出版者

Fuji Technology Press Ltd.

雑誌

Journal of Advanced Computational Intelligence and Intelligent Informatics (ISSN:13430130)

巻号頁・発行日

vol.26, no.3, pp.342-354, 2022-05-20 (Released:2022-05-20)

参考文献数

30

被引用文献数

10

---

This paper proposes a hybrid path planning and formation control strategy for multi-robots in a dynamic environment. Under a leader-follower formation structure, the followers can track the motion of one leader after the leader’s path is determined. First, a hybrid path planning strategy that contains global path planning and local path planning of the leader is investigated, in which an improved hybrid grey wolf optimizer with whale optimizer algorithm (GWO-WOA) is designed for the global path planning in a given map, meanwhile, a dynamic window approach (DWA) is fused for the local path planning to avoid dynamic obstacles. Then, a leader-follower formation control algorithm is proposed for multiple mobile robots. The followers are controlled to track their corresponding virtual robots which are generated according to the leader’s position and the formation. Finally, simulation experiments are given to demonstrate the feasibility and effectiveness of the proposed algorithm in different environments.

著者

Ryo Hanashima Takumi Tokuda Masaaki Mochimaru Junji Ohyama

出版者

Fuji Technology Press Ltd.

雑誌

International Journal of Automation Technology (ISSN:18817629)

巻号頁・発行日

vol.17, no.3, pp.248-261, 2023-05-05 (Released:2023-05-05)

参考文献数

45

被引用文献数

1

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Posture learning is required in rehabilitation and in sports such as yoga and martial arts. Virtual reality (VR) systems are being used to learn posture by superimposing the postures of the learner and instructor in cyberspace using avatars. In this study, we examined whether the presented perspective of the avatar (first-person vs. third-person perspective) and visuo-tactile feedback (tactile correct feedback + visual feedback vs. tactile incorrect feedback + visual feedback vs. visual only feedback) are effective for the posture learning. The results of an experiment (N = 24) suggested that use of the third-person perspective may result in accurate learning of the head position as compared with first-person perspective. Visuo-tactile feedback was found to improve the subjective rating on the ease of learning, while the presentation method in which tactile feedback is given when body position is correct was found to be more effective than tactile feedback given when body position is incorrect. The sense of agency was maintained at a high level under all conditions for perspective and visuo-tactile feedback and may have improved the learning accuracy of posture. The findings of this study are expected to contribute to the design of effective perspective and tactile presentation in VR-based motor learning.

著者

Yu-Ling Chen Shihmin Lo Jen-Son Cheng

出版者

Fuji Technology Press Ltd.

雑誌

Journal of Advanced Computational Intelligence and Intelligent Informatics (ISSN:13430130)

巻号頁・発行日

vol.27, no.2, pp.281-291, 2023-03-20 (Released:2023-03-20)

参考文献数

41

---

Objectives: In the past, an inherent dilemma in the education field was the difficulty in stimulating self-regulated learning. Flipped education, i.e., flipped teaching and learning, changed the teaching model, with a strategy of increasing students’ active learning during class time through a transformation of teaching and learning methods that enable students to build learning and knowledge on their own. This study investigates the impact of field-based flipped courses on college students taking up self-regulated learning and their learning performance. Methods: This study considers a national university in central Taiwan that adopts 34 field flipped teaching courses and 796 non-degree students from four colleges across all grades as the research objects, and conducts statistical analysis using descriptive statistics, t-test, ANOVA, Pearson’s correlation, and regression analysis on questionnaires to evaluate the association among variables. Findings: 1. With respect to the understanding of the uniqueness of field-based flipped teaching before and after the courses, there were differences among students in the Colleges of Education, Humanities, and Management. 2. In terms of students’ learning performance in the course pertaining to mastery over core literacy, there were differences between students of the Colleges of Education and Humanities at the beginning of the flipped-learning course. 3. There were differences among the students of Colleges of Education, Humanities, and Science and Technology in the later stage of the flipped-learning course. 4. Differences were found in the pre-test of learning performance at the grade level. 5. Self-regulated learning correlated with learning performance. 6. Field-based flipped teaching correlated with learning performance. 7. Self-regulated learning had a mediating effect on field-based flipped teaching and learning performance. Innovations: There is a little systematic discussion on the emergence and impact of flipped teaching in higher education currently in Taiwan. The authors found correlations among flipped teaching, self-regulated learning, and learning performance from the data, as well as discovered that self-regulated learning had a mediating effect on learning performance in field-based flipped teaching. Value: Making the university, when the curriculum arrangement and the development of the unique curriculum map of higher education in the future, possible to be linked with the local revitalization thinking in addition to the general curriculum, as well as being closely integrated with the local people and matters through field-flipped courses, and sustainably interacting therewith to practice university social responsibility.

著者

Kenta Suzuki Kuniaki Kawabata

出版者

Fuji Technology Press Ltd.

雑誌

Journal of Robotics and Mechatronics (ISSN:09153942)

巻号頁・発行日

vol.32, no.6, pp.1292-1300, 2020-12-20 (Released:2020-12-20)

参考文献数

11

被引用文献数

11

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This paper describes the development of a robot simulator for remote decommissioning tasks using remotely operated robots at the Fukushima Daiichi Nuclear Power Station of the Tokyo Electric Power Company Holdings. The robot simulator was developed to provide a remote operation training environment to ensure operator proficiency. The developed simulator allows for the calculation of physical aspects, such as the hydrodynamics of a remotely operated vehicle and the aerodynamics of an unmanned aerial vehicle. A disturbed camera view presented to an operator can be generated by setting parameters such as transparency, color, distortion, and noise. We implemented a communication failure emulator on the simulator in addition to functionalities for calculating the integral dose and generating the gamma camera image. We discuss the functional requirements and introduce the implemented functionalities. The simulator was built using the developed functions and can be executed integrally.

著者

Yunfan Li Yukai Gong Jyun-Rong Zhuang Junyan Yang Keisuke Osawa Kei Nakagawa Hee-hyol Lee Louis Yuge Eiichiro Tanaka

出版者

Fuji Technology Press Ltd.

雑誌

Journal of Robotics and Mechatronics (ISSN:09153942)

巻号頁・発行日

vol.34, no.6, pp.1383-1397, 2022-12-20 (Released:2022-12-20)

参考文献数

32

被引用文献数

6

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The world’s aging population is increasing. The number of elderly individuals having walking impairments is also increasing. Adequate exercise is becoming necessary for them. Therefore, several walking assistive devices have been developed or are under development. However, elderly individuals may have low motivation for exercising, or they may experience physical damage by excessive fatigue. This study proposed a method to enable elderly individuals to exercise with a positive emotion and prevent damage such as muscle fatigue. We proposed a 3D human condition model to control the walking assistive device. It includes the arousal, pleasure, and fatigue dimensions. With regard to the arousal and pleasure dimensions, we used heartbeat and electromyography (EEG) signals to train a deep neural network (DNN) model to identify human emotions. For fatigue detection, we proposed a method based on near-infrared spectroscopy (NIRS) to detect muscle fatigue. All the sensors are portable. This implies that it can be used for outdoor activities. Then, we proposed a walking strategy based on a 3D human condition model to control the walking assistive device. Finally, we tested the effectiveness of the automatic control system. The wearing of the walking assistive device and implementation of the walking strategy can delay the fatigue time by approximately 24% and increase the walking distance by approximately 16%. In addition, we succeeded in visualizing the distribution of emotion during each walking method variation. It was verified that the walking strategy can improve the mental condition of a user to a certain extent. These results showed the effectiveness of the proposed system. It could help elderlies maintain higher levels of motivation and prevent muscle damage by walking exercise, using the walking assistive device.

著者

Akiko Sakamoto Koichi Nishiya Xuanjin Guo Airi Sugimoto Waka Nagasaki Kaito Doi

出版者

Fuji Technology Press Ltd.

雑誌

Journal of Disaster Research (ISSN:18812473)

巻号頁・発行日

vol.17, no.3, pp.327-334, 2022-04-01 (Released:2022-04-01)

参考文献数

32

被引用文献数

6

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Of the four atoll countries in the world, the Maldives has the lowest average elevation. Therefore, it is likely to be the first country to lose its land when the sea level rises due to climate change. As a countermeasure to sea level rise, the government of the Maldives is constructing an artificial island called Hulhumalé by raising an atoll adjacent to the capital city of Malé. Other atoll countries may employ the same method to adapt to the anticipated sea level rise. There is a concern that people who are forced to relocate to the artificial island will be affected in various ways. Therefore, the purpose of this study was to identify measures to reduce the potential impacts of migration to artificial islands. This study aimed to identify factors that will work effectively to satisfy migrants from outside the Malé region to Hulhumalé. At this stage, sea level rise is not a motivating factor for migration to Hulhumalé. For the time being, enhancing high-income employment and high-level education in Hulhumalé, which are the main motivations for migration, will help sustain voluntary migration. Over the past two decades, rapid economic growth has changed the desire of Maldivians. Hulhumalé is attracting people with its new urban environment and employment opportunities. A small-scale questionnaire survey on the satisfaction level of post-migration life was conducted among the residents of Hulhumalé and the results showed that those who changed their jobs before and after migration were less satisfied with their migration than those who did not. In Hulhumalé, smart cities are being developed and new types of employment are being created. In order to facilitate the smooth migration of residents from remote islands, policies that focus on occupational changes before and after migration are needed, such as public job placement programs that enable migrants to find the same jobs that they had before migration, and job training programs that prepare them for career changes and enable them to adapt smoothly to new jobs. At present, mental health issues among migrants are not a major problem. Strengthening people-to-people networks through the use of information technology (IT) will contribute to smooth migration and resettlement.

著者

Nobutsuna Endo Yuta Kizaki Norihiro Kamamichi

出版者

Fuji Technology Press Ltd.

雑誌

Journal of Robotics and Mechatronics (ISSN:09153942)

巻号頁・発行日

vol.32, no.5, pp.894-902, 2020-10-20 (Released:2020-10-20)

参考文献数

16

被引用文献数

12

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There are not many physical models of oral and laryngeal systems for human speech movement in both computer simulators and mechanical simulators. In particular, there is no robot tongue mechanism that completely reproduces the deformation motion of the human tongue. The human tongue is an aggregate of muscles devoid of a skeleton. It only possesses a small hyoid. The purpose of this study is to develop a flexible actuator without a rigid link, aiming at the development of a tongue mechanism for a mechanical speech robot. We propose a flexible pneumatic bending actuator using thin McKibben muscles and a soft body formed by a silicone resin. We have verified its mechanical characteristics and described a control method for displacement and curvature. The elasticity/compliance of the silicone resin forming the soft body of this actuator was quantified by tensile tests. The oscillation parameters were identified, and it is suggested that the dynamic model can be described by a spring-mass-damper system. Assuming an arc-shaped deformation model, a simultaneous control system for the arc length and curvature was constructed and its effectiveness was confirmed.

著者

Hong-Xia Xie Yan Feng Xue-Yong Yu Yu-Ning Hu

出版者

Fuji Technology Press Ltd.

雑誌

Journal of Advanced Computational Intelligence and Intelligent Informatics (ISSN:13430130)

巻号頁・発行日

vol.27, no.1, pp.105-118, 2023-01-20 (Released:2023-01-20)

参考文献数

25

被引用文献数

1

---

As a new type of digital currency, Bitcoin is considered as “future gold” by various scholars. Therefore, this study considers Bitcoin and gold as a group of hedging assets to conduct investment research and it also discusses the investment rules between Bitcoin and gold: prediction of the rise and fall of Bitcoin, comparison of the characteristics of Bitcoin and gold, and the impact of the transaction procedures of Bitcoin and gold on the final trading results, and formulates trading strategies through optimization algorithms. Then, four machine learning algorithms, i.e., LSTM, BP neural network, Adaboost, and Bagging, are introduced to predict the rise and fall of gold and Bitcoin the next day, and then, the entropy weight method is used to synthesize four predicted results to ensure the robustness of the predicted results. To establish the optimal trading strategy, this study considers the maximum expected return as the goal to develop a single-objective optimization model and historical five-day price volatility as a risk factor. In this study, ant colony, simulated annealing, and genetic algorithms are used to solve the single-objective optimization model. Finally, we conclude that Bitcoin, similar to other financial assets, e.g., gold, is sensitive to shocks and volatile and possesses a relatively quiet cycle. When Bitcoin has an asymmetric impact, Bitcoin and gold can equally treat transactions.

著者

Masaki Takahashi Maya Yasui Tatsuo Kanamaru Mitsuhiro Nakagawa

出版者

Fuji Technology Press Ltd.

雑誌

Journal of Disaster Research (ISSN:18812473)

巻号頁・発行日

vol.17, no.6, pp.1080-1089, 2022-10-01 (Released:2022-10-01)

参考文献数

30

被引用文献数

1

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The eruptive volumes and ages of the large-scale pumice eruptions of the Asama-Maekake volcano were obtained from extensive trench-based surveys. The calibrated radiocarbon age unit (CRAU) was adopted instead of each calibrated radiocarbon age. From the high-resolution tephro-stratigraphy of large-scale pumice eruptions and CRAU dating, the eruptive history of the Asama-Maekake volcano is divided into three active and two moderately active stages as follows: active stage I (9430 to 7260 ycalBP), moderately active stage 1 (7261 to 6446 ycalBP), active stage II (6447 to 3160 ycalBP), moderately active stage 2 (3161 to 1819 ycalBP), and active stage III (1820 ycalBP to present). The eruptions of the Asama-Maekake volcano consists of small-scale (phreatic to phreato-magmatic), intermediate-scale (Vulcanian), and large-scale pumice eruptions (sub-Plinian). The active stages were characterized by the occurrence of large-scale pumice eruptions. In the moderately active stages, pumice producing eruptions were lacking but instead Vulcanian eruptions dominated. A step diagram showing the relationship between eruption volumes (DRE) and ages (CRAU) is proposed, which indicates that active stage III is not time-predictable but is volume-predictable; if the large-scale pumice eruption occurs in 2022 AD, the forecasted eruptive volume is approximately 0.21 km3. The eruption rate is not constant and changes in each stage, and the average eruption rate of active stage III (0.0011 km3/year) is larger than those of active stage I (0.00006 km3/year) and II (0.0001 km3/year).

著者

Lei Zhou Jingjie Wu

出版者

Fuji Technology Press Ltd.

雑誌

International Journal of Automation Technology (ISSN:18817629)

巻号頁・発行日

vol.16, no.4, pp.386-402, 2022-07-05 (Released:2022-07-05)

参考文献数

125

被引用文献数

9

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Precision motion systems are the core of a wide range of manufacturing equipment and scientific instruments, and their motion performance directly determines the quality and speed of the associated manufacturing or metrology processes. Magnetically levitated precision motion systems, where the moving target is supported by magnetic forces and without any mechanical contact, provide advantages of frictionless motion, vacuum compatibility, and contamination-free operation. These features endow the magnetic levitation technology with the capability to deliver excellent overall performance for precision positioning systems. Through decades of research and engineering efforts, significant advances have been made in the actuation, sensing, design, and control of magnetically levitated precision motion systems. This paper provides an introduction to the fundamentals of the feedback control, actuation, and sensing for the magnetic levitation technology, and provides a comprehensive literature review of various magnetically levitated precision positioning systems developed over the past three decades. The final part of this paper identifies several challenges in the design and control of today’s precision motion systems using magnetic levitation and provides an outlook on the possible directions for future research and development.