Naohiko Kohtake

• PhD, PMP
• Professor at Keio University

To effectively address environmental and social issues such as climate change and sustainability, it is necessary to build a conceptual model that allows stakeholders with different perceptions and values to reach a consensus and make decisions toward achieving the desired goals. The construction of conceptual models using participatory modeling me...

Tourism has been a significant source of revenue for Thailand. However, during COVID-19, Thailand’s tourism-related businesses, such as hotels, accommodation, and transportation, suffered greatly. Nakhon Si Thammarat is a second-tier Thai province in the country’s south. Although the tourism businesses in this province suffered during COVID-19, the...

From August to October 2024, severe flooding in Northern Thailand, triggered by heavy rains and Typhoon Yagi, caused deaths, injuries, and extensive damage. This preliminary report outlines the disaster timeline, impact, and response actions, including the operations center establishment. The inundation areas are presented using satellite data and...

Providing information to emergency responders and citizens is one of the most critical aspects during bushfire events. In many cases ground-based infrastructure might be malfunctioning or destroyed and satellite communication might appear the only option. This paper concentrates on the use of the QZSS satellites to provide short messages early warn...

A noninvasive, immediate, and convenient method for assessing muscle tissue status during exercise-induced muscle damage (EIMD) has not been established. This study was designed to assess and determine parameters suitable for measuring EIMD after eccentric exercise, using multi-frequency bioimpedance analysis (BIA). Thirty-five young male participa...

This study aimed to evaluate the effects of different target distances on various leg joints in the fencing lunge (lunge). Fifteen fencers performed the lunges from three different target distances (normal, short, and long). Joint angle data in the sagittal plane of the hip, knee, and ankle of the front and rear legs were measured using a 3D motion...

This research aimed to elucidate whether there were differences in physical characteristics and performance across starter and non-starter players in Japanese elite-level female soccer in college. Twenty-four college players (age: 19.8 ± 0.8 years, body height: 160.3 ± 4.0 cm, body mass: 55.2 ± 5.2 kg) participated in this study. We assessed the co...

Introduction The fencing lunge (lunge), characterized by minimal body rotation, offers a movement well-suited for 2D video analysis. However, to the best of our knowledge, the validity of 2D video analysis for fencing has not been verified. This study aimed to validate 2D video analysis by comparing lower limb joints (hip, knee, and ankle joints) a...

The purpose of this study was to examine the feasibility of an intervention program focused on career transition psychological support for retired Olympic athletes in Japan. It was expected that the intervention program would significantly enhance knowledge about career transition support for athletes and also enhance attitudes towards seeking care...

To date, noninvasive and immediate assessment of muscle tissue status after exercise-induced muscle damage (EIMD) has not been established. This study was designed to assess and determine parameters suitable for measuring EIMD after eccentric exercise, using multi-frequency bioimpedance analysis (BIA). Thirty-five young male participants performed...

We investigated the influence of advance lunging in fencing from the perspective of velocity and lower limb joint angles to identify how the joint angles contribute to the peak velocity in a lunge with advance (LWA). Fourteen skilled athletes (age: 19.6 ± 0.9 years, height: 171.2 cm ± 5.2 cm, weight: 63.7 kg ± 5.3 kg, and fencing experience: 9.7 ±...

Developing regions are vulnerable to disaster with limited ICT technology, and there are challenges in reducing flood damage through early warning systems. As a countermeasure, Community-based Flood Early Warning System (CBFEWS) based on sociotechnical systems developed by integrating low-cost technologies and human-centered communication networks...

This study aimed to design a multi-faceted intervention system for reducing household food loss and waste among young people in the 20-30 year age range and from various family configurations. The intervention system combined several methods, such as recording and feedback, communication, and prompts. The results showed that food photography and fe...

The purpose of this study was to compare the characteristics of starters and non-starters with respect to the anthropometric and physical fitness in a Japanese university rugby team. Our sample pool consisted of 54 players of the K University rugby team, who were registered for the official games (all 7 games/year) in 2018 and 2019. The starter gro...

Delayed recovery of the core body temperature after exercise adversely affects physiological functions, and the effects of ingesting lower-temperature ice slurry on post-exercise recovery remain unclear. We investigated the effects of ingesting −2 °C ice slurry on physiological recovery after field-based rugby union training. Fifteen university rug...

This study aimed to investigate the relationship between the muscle shear modulus of the biceps brachii, urinary titin N-terminal fragment (UTF), and other damage markers after eccentric exercise. Seventeen healthy males performed five sets of ten eccentric exercises with dumbbells weighing 50% of the maximum voluntary contraction (MVC) at the elbo...

In the event of a crisis, companies in industrial complexes and surrounding regional organizations that share production bases and operating resources need to manage business continuity through coordinated mutual cooperation in public and private sectors, in addition to their individual business continuity plans (BCPs). This framework of collaborat...

Ice slurry ingestion enhances exercise performance by lowering the core body temperature. However, an operational issue related to this ingestion is the requirement for a high intake of 7.5 g·kg⁻¹ to produce the desired effects. We investigated the effects of the intake of low amounts of ice slurry at −2°C on the tympanic temperature and exercise p...

The aim of this study was to investigate the effect of ingestion of ice slurry before bedtime on the sleep quality of rugby union players in the summer season. Thirteen healthy male university rugby union players volunteered for this study. The participants ingested either ice slurry or a room-temperature beverage (control) 30 min before bedtime. A...

การเดินทางท่องเที่ยวเป็นเรื่องสะดวกขึ้นเมื่อข้อมูลข่าวสารเข้ามาเป็นปัจจัยที่สำคัญในการส่งเสริม การตัดสินใจของผู้คน จึงไม่แปลกที่การเดินทางท่องเที่ยวกลายเป็นกิจกรรม หรืองานอดิเรกของผู้คน อย่างไรก็ดีด้วยวิกฤตสถานการณ์โรคระบาดโควิด-19 นั้นได้กระทบกับธุรกิจท่องเที่ยวโดยตรง และส่งผลกระทบเป็นวงกว้าง การเตรียมความพร้อมเพื่อการฟื้นฟูอุตสาหกรรมท่องเที่ยวจึง...

Transportation is considered to be one of the main activities of daily life. The COVID-19 pandemic, which had its origin at the end of 2019, restricted the movement of the people due to its deadly impacts. Most governments also had a hand in limiting the mobility of the people through various measures and policies. Thailand was one of the first cou...

There is a growing need to introduce warning dissemination systems in disaster-prone regions to improve the coverage of information distribution. In this study, a warning dissemination system was designed in which disaster information transmitted by a global navigation satellite system (GNSS) is received by terrestrial infrastructure, such as siren...

The purpose of this study was to design and evaluate an online real time off-ice training program (OOTP) leading to the basic figure skating motions, and maintaining and improving motivation for adult novice skaters. In addition, the impact of image-based extrinsic feedback on OOTP was also investigated. Twenty-two novice figure skaters were divide...

The impacts of disasters are increasing due to climate change and unplanned urbanization. Big and open data offer considerable potential for analyzing and predicting human mobility during disaster events, including the COVID-19 pandemic, leading to better disaster risk reduction (DRR) planning. However, the value of human mobility data and analysis...

【Job: Columbia University is looking for a postdoc related to this paper's project. https://bit.ly/3ksrqOA】 The impacts of disasters are increasing due to climate change and urbanization. Big and open data offer considerable potential for analyzing and predicting human mobility during disaster events, including the COVID-19 pandemic, leading to be...

In the development of satellite services, it is necessary to deal with issues unique to space systems, such as non-repairable systems, high costs, and orbital constraints. Service expansion by interoperation between similar systems is effective, but the quality evaluation of the cooperation architecture is complex problem. In our research, we propo...

The effects of COVID-19 measures on the quantitative changes in atmospheric substances associated with economic activities have been explored in various studies. However, the specific relationship between the changes in economic activities due to government interventions and the associated changes in atmospheric substances remains unclear. This rel...

Various sports have started to use tablet devices and sports devices for training. The purpose of this study is to clarify the difference in the effectiveness of direct instruction and video-based instruction for improving tag rugby skills. Direct instruction consisted of demonstrations of passing and catching, and video-based instruction consisted...

本研究では，小学校高学年の探求学習における共同学習時の個人の発言量の偏りを減少させ，個人の発言量を増加させるグループ編成アルゴリズムを設計し評価した．アルゴリズムに児童の興味領域や能力，性格特性データを入力することで，１万通りのグループの組み合わせを作り，個人の予測発言量，グループ内の予測発言量平均値と発言の偏りを予測し，個人の発言量が増加する組み合わせを算出することが可能である．このアルゴリズムによる発言量の偏りの予測精度，発言量の偏り，個人の発言量変化の３つの観点から有効性を評価するため，埼玉県内の小学校で児童を対象に実際にこのアルゴリズムに基づいてグループ編成を行い，共同学習の発話の録音分析とその授業を担当した教員へのアンケートを実施した．その結果，発言量の予測値と実測値には相関が見ら...

In the event of a large-scale disaster, the dissemination of audible disaster warning information via sirens is effective in ensuring a rapid response. Sirens can be installed not only on fixed towers, but also on public transport and other vehicles passing through residential areas, and at spots where residents congregate, to increase area coverag...

Alternative data is increasingly utilized for credit evaluation of financially excluded persons. However, requirements, such as reliability, which gain new importance when alternative data is employed for credit evaluation, have not been considered as part of the credit scoring process. This research proposes an approach for incorporating context-s...

Feature selection is crucial to the credit-scoring process, allowing for the removal of irrelevant variables with low predictive power. Conventional credit-scoring techniques treat this as a separate process wherein features are selected based on improving a single statistical measure, such as accuracy; however, recent research has focused on meani...

There has been a growing recognition that a systems thinking approach, which pays attention to the entire dynamic system, its constituent parts and the interactions among those parts, is an effective approach for tackling complex issues that exhibit nonlinear behaviour and involve multiple stakeholders. To understand a complex system, a systems thi...

Credit scoring of financially excluded persons is challenging for financial institutions because of a lack of financial data and long physical distances, which hamper data collection. The remote collection of alternative data has the potential to overcome these challenges, enabling credit access for such individuals. Whereas alternative data source...

The purpose of this research is to design the architecture of an early warning system with Global Navigation Satellite System (GNSS) and terrestrial infrastructure for improving coverage of disaster information dissemination. In the proposed architecture, necessary segments and information flow are identified to introduce an early warning system to...

Numerous studies have been conducted on indoor and outdoor seamless positioning and indoor–outdoor detection methods. However, the classification of real space into two types, outdoor space and indoor space, is difficult. One type of space that is difficult to classify is top-bounded space, which can be observed in commercial facilities, logistics...

Psychological support systems for retiring elite athletes can assist them in making career transitions out of sport. The purpose of this study is to further advance research in this area, with a specific focus the developmental experiences related to the sport career transition process in Japan. One retired Olympic medalist was analyzed with a life...

With the widespread use of indoor positioning technology, various services based on this technology are beginning to be offered to consumers and industrial applications. In the case of logistics facilities, in addition to indoor and outdoor spaces, there are top-bounded spaces (TBSs): elongated areas that are covered with roofs or eaves on the uppe...

Abstract—The Japan Sports Agency has made efforts to unify several career support programs for Olympic athletes prior to the 2020 Tokyo Olympics. One of the programs, the Japan Olympic Committee Career Academy (JCA) was established in 2008 for Olympic athletes at their retirement. Research focusing on the service content of sport career support pro...

Understanding of system requirements that satisfy end users’ needs is fundamental of system development, yet challenging when end users are unable to address their needs explicitly. Although a number of scholars have been designing and applying requirement elicitation techniques, there is a research gap in Spatial Decision Support System (SDSS) wit...

The semi-outdoor space covered with the upper part and open on the side is difficult to apply the existing indoor-outdoor seamless methods because the GPS positioning accuracy is reduced but some degree of GPS signal can be received. In order to detect a stay in such a special environment, we designed a method to select satellites for stay detectio...

Taking action for evacuation immediately is the most important and effective measure when tsunami attacks in the aftermath of a large earthquake. In this paper, a concept of delivering the least amount of emergency warning information and location based information possible is presented with a design of indoor/outdoor seamless positioning and emerg...

To realize indoor location based services, indoor positioning function is the main function. However, available solutions such as Google Maps are not provided yet. In most cases, it is necessary for the service provider to develop the positioning environment themselves. We consider that this point is one of the reasons why indoor positioning techno...

The analysis of sports data using GNSS has spread to the managers of high-performing soccer and rugby teams, but it has only received limited attention in other sports. This may be because the device and operating costs of GNSS receivers are high, and analysis and evaluation methods have not been well established. In this study, we created a framew...

For large and complex systems, such as space applications, there exist several cases wherein civilian and defence stakeholders enable interoperability and data sharing with each asset. For this reason, there is concern that both stakeholders are hesitant to architect a dual-use system. This study aimed at optimization by searching for points where...

Emergency relief just after the disaster strikes requires quick response to reach the emergent needs based on correct information and decision making. Currently rescue teams collect or receive the information and data of the affected areas from both ground survey by local authority and the observation and analysis from the external players includin...

Precise deterioration prediction of individual section is effective for planning and implementing effective maintenance and management measures of social overhead capital, but deterioration prediction of social capital is difficult because complicated factors are involved. This paper proposes a method of predicting the road pavement condition value...

Cross-sectional communication for data sharing among multiple stakeholders involved in disaster responses is one of the fundamental non-structural measures that directly influence the performance of disaster risk reduction. Taking the event of the 2008 Cyclone Nargis as the watershed experience, Myanmar has been developing a nationwide disaster ris...

Prior to the 2020 Tokyo Olympics, the purpose of this research is to investigate Japanese olympians’ causes of career termination depending on the differences between Summer/Winter and male/female olympians. The olympians registered in the Olympians Association of Japan (OAJ) were asked: 1) the lengths of the sport career until first participation...

The pavement deterioration prediction model is a basic module of the PMS (Pavement Management System), and its prediction results influence the decision making of pavement administrators. Hence, it is very important to improve prediction accuracy. There is a rutting depth as a major indicator showing the state of pavement used in PMS. In this resea...

A health information system is a system of systems that serves as a foundation of health information used for the evidence-based decision making of public health actions. Since practical solutions for addressing system transformation and its effect on system management have not been extensively discussed, this study examines an approach to model an...

This paper describes a novel science education program called “localized science education program” that covers topics of a local area, such as its natural wonders, and involves community residents to cultivate an intergenerational community. The science education program has three features: (1) the ability to learn collaboratively is fostered, (2)...

Due to the associated and substantial efforts of many stakeholders involved in malaria containment, the disease burden of malaria has dramatically decreased in many malaria-endemic countries in recent years. Some decades after the past efforts of the global malaria eradication program, malaria elimination has again featured on the global health age...

Who are you? This is a crucial question when one wants to assert himself/herself in a global competitive environment. Characteristics of individuals differentiated from others are affected by 4 key components; (1) Values: foundation of how one finally decide, (2) Skills: technical expertise and language proficiency, (3) Knowledge: information and e...

In order to realize effective pavement maintenance and management, it is necessary to predict the future state change by prediction of pavement deterioration and to optimize the maintenance and management cost such as inspection, repair, renewal etc. Various pavement deterioration prediction models have been proposed, but it is not easy to determin...

In order to improve the efficiency of social capital management, it is required to develop an information infrastructure in which information such as facility information and inspection history is stored in a database, and to utilize the accumulated information. Although it is possible to construct a deterioration prediction model from such informa...

The threat by the space debris in space activities has accelerating the necessity to take the measures against space debris, especially to remove the space debris, so-called, Active Debris Removal (ADR). The objective of this paper is to design the international framework to operate ADR from the systems engineering point of view, not only technical...

Evacuation trainings have been conducted as an effective action to protect people from incoming tsunamis in case of a big earthquake. This research addresses limitations of existing conventional "event-style" tsunami evacuation trainings, that are inflexibility in disaster scenarios, training timings, training locations, and participatable trainees...

The disease burden of malaria has decreased as malaria elimination efforts progress. The mapping approach that uses spatial risk distribution modeling needs some adjustment and reinvestigation in accordance with situational changes. Here we applied a mathematical modeling approach for standardized morbidity ratio (SMR) calculated by annual parasite...

Schematic overview of modeling and mapping method for the fine-scale malaria risk map. (DOCX)

One of the key responsibilities of any government is to communicate and disseminate safety information and warnings to the general public in case of an emergency. Traditionally, warnings are issued by the government through a broadcast approach using communication channels such as TV and radio. However this monopolistic approach is now challenged b...

As train stations have become increasingly convenient as they grow bigger and more multifunctional, both in urban and rural areas in recent years, there are also challenges to provide users with easy-to-understand guidance and information in increasingly complex indoor spaces. This paper presents the results of a demonstration experiment using the...

A common approach in concept selection methods is to gather customer requirements and needs based upon missions or operational scenarios; these requirements and needs lead to objectives that are useful in concept selection methods. However, when introducing new, cutting-edge technology, it is extremely hard for researchers or developers to gather c...

Information blackout may occur in which it becomes difficult to obtain required information because information infrastructures have been destroyed. Infrastructures for providing disaster information are vulnerable in some Asian regions, so it is vital to cover such blanks to minimize damage. Much attention has been given to a method for communicat...

Warning systems are relied on worldwide as part of disaster risk reduction. The traditional model of a government monopolistic system supplying warnings through a broadcast approach is now challenged by new media, mobile technologies and the accompanying expectations of individualised warnings to personal mobile devices. We examine this situation,...

This chapter proposes application of framework of system design of a special zone for reconstruction of Fukushima Prefecture which suffered serious damages from the Great East Japan Earthquake, tsunami and nuclear accident at the Fukushima Daiichi Nuclear Power Plant. The framework of system design used in this chapter is called the Interactive Soc...

The authors have established a systems engineering (SE) and project management (PM) educational program for university students developing a 1kg-class simulated-satellite, called CanSat. The educational program helps students achieve mission success through the practical application of SE/PM methodologies to their development processes. In the educ...

This paper describes an enhanced participatory process created to support a regional vitalization project run by residents of a local community in Japan. The experiences and lessons learned during this project are shared. Since the local residents were unaccustomed to participatory design, it was a challenge to motivate them to contribute to the pr...