SACM - Japan
Permanent URI for this collectionhttps://drepo.sdl.edu.sa/handle/20.500.14154/63918
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Item Restricted Spillover-Based Portfolio Management: Bayesian Diebold & Yilmaz Spillover Applications in Cryptocurrency Market(University of Tokyo, 2025) Bukhary , Husam; Gento, MOGIThis study evaluates the performance of various Bayesian priors in modeling and assessing financial and economic Diebold and Yilmaz spillover networks through simulations using the posterior distribution of spillover effects across multiple priors. A key contribution of this research is the introduction and validation of graph similarity analysis within spillover networks, demonstrating that even when the overall fit of the spillover is suboptimal, the interconnections between variables of interest are accurately captured in terms of directionality, albeit with slight discrepancies in magnitude. Building on this insight, we apply the Diebold and Yilmaz spillover approach to develop a novel portfolio optimization strategy that integrates Hierarchical Risk Parity (HRP) with the Louvain method, utilizing the optimized spillover values. This innovative method outperforms traditional HRP techniques when applied to both synthetic data and real cryptocurrency market data, providing a robust and efficient framework for managing interconnected financial assets.5 0Item Restricted Role of Artificial Intelligence in Enhancing Metaverse Gaming Experience and Human Interaction: A Case Study of Roblox's AI Implementation(Tokyo University of Technology, 2025) Alotaibi, Omar; Kameda, HiroyukiArtificial Intelligence (AI) is a tool that is useful for enabling and sustaining the Metaverse gaming experience by infusing virtual reality (VR), augmented reality (AR), extended realities (XR), and blockchain. The current research focused on identifying the impact of AI in leveraging immersive experiences and improving human interaction, which plays a crucial role in Metaverse gaming. A quantitative analysis carried out surveys from 200 randomly sampled respondents involved in Metaverse gaming. Using SPSS 26.0, correlation analysis showed that association between the values of ‘r’ of variables Immersive Gaming Experience (r=0.983**), Deep Learning Collaboration (r=0.957**) and Increased Human Interaction (r=0.979**) are greater than 0.7 depicting strong correlation with Metaverse gaming. Regression analysis further confirmed that the role of AI in enhancing the Metaverse gaming experience and human interaction is significant. With the considerable success of AI in Metaverse, the role of DL algorithms is also groundbreaking in leveraging game balance in multiplayer games, satisfying play-testers and designers who own valuable features, real-time rendering, and multi-user design collaboration.7 0Item Open Access New Daily QA phantom for proton beam spot scanning(University of Tsukuba, 2024) Zakariya ,Maryam Zakariya A; Sakae, Takeji; Isobe, TomonoriPurpose: The purpose of this research is to create a new design for a daily quality assurance phantom in proton pencil beam system. Using a single spot of a proton beam, this phantom should measure some of the factors necessary for daily QA dosimetry, such as Range Check, Beam Size, and Position Accuracy. Material and Method: Measured depth dose data is used to determine the depth 90% (d90%), which is an important point for accurate measurements of the QA phantom thicknesses. The QA phantom experimental tests were conducted using broad beam and pencil beam systems. To get the results of range confirmation and QA dosimetry measurements, both systems used a QA phantom with a scintillator system. In the broad beam system, the QA phantom design was a One-Step phantom, and for the pencil beam system, the QA phantom design was modified to a check pattern and named as a (Check phantom). The check phantom was tested in the broad beam system, with a small aperture collimator to simulate the pencil beam. Analytical calculations of depth dose were performed for each system condition to get the comparison results of experimental data and analytical calculation. The final results of experimental and analytical calculation were evaluated by using the B/A ratio method, where A is the Proximal dose of d90% and B is the Distal dose of d90%. Results: The results of the one-step phantom for experimental data and analytical calculation are summarized in the B/A ratio figure. Using the scintillator system with the QA phantom caused a quenching effect in the experimental data. The quenching was calculated analytically, and the results of the quenching calculation and experimental data show similarity in the B/A ratio data. The experimental data of the check phantom was analyzed by using the 2D Gaussian fitting method. To obtain the results of experimental data and analytical calculation in B/A ratio, the analytical calculation of depth dose for the check phantom is processed with the same calculating methods as in the one-step phantom, except incorporating the scattering effect of pencil beam dose distribution. The final results for both QA phantoms (One-Step and Check) show a consistent B/A ratio, and the new design check phantom confirmed its usability for daily QA phantom. Conclusion: The check phantom is eligible for daily QA phantom, with a one-spot of beam, it analyzes the required dosimetry measurements for daily QA.5 0Item Restricted Study of clinicopathological factors related to recurrence, metastasis, and prognosis in lower gingival squamous cell carcinoma(Hokkaido University, 2025-03) Alanazi, Hamad Khalaf; Wataru, Kakuguchi; Yoichi, OhiroLower gingival squamous cell carcinoma (LGSCC) poses a unique challenge in oncology due to its frequent early bone invasion, a characteristic stemming from its anatomical location. This often results in an overrepresentation of T4 staging within the traditional TNM system, which primarily relies on tumor size and extent. Consequently, the TNM staging may not accurately reflect the true biological behavior and prognosis of LGSCC, as it neglects other critical factors influencing disease progression. This study aimed to address this discrepancy by investigating the limitations of the current TNM system in predicting LGSCC outcomes and identifying additional prognostic factors that could contribute to a more comprehensive and accurate risk assessment. To investigate the limitations of the standard TNM staging system in lower gingival squamous cell carcinoma (LGSCC), a retrospective analysis was performed on 104 patients treated at Hokkaido University Hospital. This study expanded beyond traditional TNM staging by incorporating detailed histopathological evaluations, including YK classification for bone invasion, worst pattern of invasion (WPOI), grade of differentiation, and depth of invasion (DOI). Utilizing Kaplan-Meier survival analysis and chi-squared tests, the study aimed to identify additional prognostic factors that could refine risk assessment, demonstrating that DOI, patient age, and WPOI, in conjunction with traditional T staging, significantly influence disease outcomes, emphasizing the necessity of incorporating histopathological features for more accurate LGSCC prognostication.4 0Item Restricted Flash Flood Hazard Assessment using Hydrological and Machine Learning Models with Multi-Satellite-Based Precipitation and d4PDF Climate data sets in Saudi Arabia(Kyoto University, 2025) Alamoudi, Fahad; Kantoush, SamehFloods are among the most prevalent natural hazards globally, causing significant damage and loss of life. The primary tool for flood risk assessment and damage mitigation is hydrologic early warning systems, which predict flood events using rainfall observations from ground stations. However, challenges such as data scarcity, spatial disruption, network density issues, and measurement errors in ground stations have necessitated using satellite-based rainfall products to address these limitations. Satellite-based precipitation estimates (SbPEs) and reanalysis precipitation datasets (RPDs) have become increasingly accurate, offering improved spatial and temporal resolution beneficial for hydrological applications and rainfall-runoff modeling. The challenges posed by climate change, particularly the increasing frequency of extreme events like floods, further complicate flood risk assessments, especially in regions like Saudi Arabia. The main challenge in assessing rainfall and runoff in Saudi Arabia is the limited availability and accuracy of observational data (1) rainfall station and monitoring that can be measured with reliable and less uncertain data with low maintenance cost. In addition, the extreme climatic variability under climate change impact with dam management and mitigation measures in KSA (2) the identification of suitable locations for new dams where they can effectively serve multiple purposes, including groundwater recharge, flood control, water storage, and protection. Therefore, the main objectives of this research thesis are to (1) Examine both the hydrological model and Machine learning to develop the flash flood susceptibility maps, (2) Deep understand the Spatiotemporal climatic variability of extreme storms, (3) To evaluate SBP rainfall data and Re-analysis Rainfall data over KSA, and (4) To develop Flood Hazard Map based on SBP and hydrological modeling including distribution of dams locations and purposes. This thesis consists of seven chapters that explain the flood risk assessment from different sources of rainfall data and culminate in the analysis of extreme rainfall in the present and future, using hydrological models and machine learning techniques to find the hazard mapping over Saudi Arabia. The introduction and the literature review about the rainfall-runoff processing under climate change in Saudi Arabia were presented [Ch.1, 2]. Afterward, a set of investigations was conducted through various analyses and modeling to find out the flash flood hazard and susceptibility map [Ch.3, 4, 5, 6]. Finally, the recommendation and future prospects were proposed with research conclusions in [Ch.7].18 0Item Restricted The integration process of the environmental, social and governance (ESG) factors to a firm's business model(Keio University, 2024) Aldowaish, Alaa; Kokuryo, Jiro; Isagai, Yoshinori; Kotosaka, Masahiro; Hoda, TakaakiThis thesis examines the integration process of ESG into the business model. It consists of three stages. In the first stage, we asked the research question of how the literature examines the relationship between ESG and business models. We conducted a systematic literature review of 326 papers about ESG and business models; we found only 29 discuss ESG and business models. Also, we found that the majority of the literature focuses on outcomes such as integration behavior, advantages, practices, and critical, and only two explain the process. We extended our literature and examined sustainability as a synonym of ESG. We found few discussions on the process and were limited to the early stage of sustainability integration. The second stage we asked is ESG integrated into the business model. We conducted a comparative analysis of corporate narrative reports in Japan and Europe. We used legitimacy theory to understand firms' behavior in integrating ESG into the business model; we applied a content analysis and analyzed 70 reports of 35 firms. We found the majority to be a general statement followed by concrete activities and aspirational targets, and only one mentioned a systematic dimension. We address the validity of this stage by examining the synonym of ESG, sustainability. We found that the same pattern exists for the findings. In the third stage, we examined the ESG integration process in two case studies. We asked our main research questions from an operational perspective: how is ESG integrated into the business model? Moreover, from a theoretical perspective, how do firms manage conflict in ESG integration? Finally, we used process theory to propose a framework for integrating ESG into a firm's business model. The framework synthesizes two process models identified from a systematic literature review of sustainability and business models and the successful case study.7 0Item Restricted A Comparative Study on the Characteristics of Architects' Licensure System in Different Regions(University of Tokyo, 2024) Almusallam, Nouh Abed; Otsuki, ToshioThere is constant pressure of globalization that demands constant and developed adaptation, particularly in response to the ever-evolving role and responsibilities of an architect. Many addressed the architect regulation through eligibility of education, experience and practice. However, a comparative study and analysis of different licensing systems encompassing backgrounds, current eligibilities, entities and regulation that influence licensure systems across nations, particularly considering the simultaneous inclusion of the Middle East and East Asia within the same analytical framework, has been overlooked. Therefore, this study identifies the characteristics of the variables systemizing the registration procedure that defines a licensed architect in different regions.10 0Item Restricted Application Study of Adaptive Mesh Refinement Method on Unsteady Wake Vortex Analysis(Tokai University, 2024) Alzahrani, Haneen; Sakai, TakaakiThere is a possibility of Ar cover gas filled in the upper part of the reactor vessel (RV) to get into the sodium coolant by vortices causing output disturbance. Hence, it is necessary to evaluate this gas entrainment phenomenon. To predict the flow pattern in the upper part of the RV by Compurational Fluid Dynamics (CFD) analysis, there is a need to establish an appropriate mesh arrangement. In this study, the applicability of the Adaptive Mesh Refinement (AMR) method to predict gas entrainment vortices accurately was examined. An initial coarse mesh (20mm) that simulate the test section of the experimental apparatus in the circulating water loop was created. The initial mesh was refined with two indexes: the first index (Index- 1) is when the second invariant Q of the velocity gradient tensor is negative and the second one (Index-2) is the pressure gradient index added to the Index-1. Then, transient calculation was performed on the refined meshes under each condition, and the results were compared with a Reference mesh with cubic cells of 5 mm width. As a result, comparing the pressure distribution of the Reference mesh with other meshes refined with the two indexes, Index-2 was found to be more similar to that of the Reference mesh. In conclusion, the applicability of the AMR method with the condition of the Index-2 was confirmed for this experimental system in which unsteady wake vortices are generated. In addition, to confirm the applicability of the AMR method on actual reactors, a simulation of the upper plenum of SFR was conducted. Results indicate that AMR method is also applicable, and the analysis load can be reduced up to 600%.7 0Item Restricted ANALYSIS OF CYBERSECURITY INTEGRATION AND LEGISLATIVE STRATEGIES IN JAPAN(Kyushu University, 2024-08-21) Aldhafeeire, Salman; Jiro, HasumiThis thesis analyzes Japan's national security strategy, which integrates cybersecurity and legislative strategies in response to evolving global cyber threats. The thesis emphasizes the growing importance of cybersecurity in an ever-evolving cyberspace, where state-sponsored cyber-attacks pose significant risks to national security, individual privacy, and economic stability. It explores Japan's proactive policies to cybersecurity integration, considering the interconnected nature of information warfare in the contemporary geopolitical landscape. Despite a historical aversion to militarization, the challenges posed by cyber threats necessitate a pragmatic response, resulting in the delicate balance between defending against cyber threats and upholding pacifist ideals. The research questions focus on understanding how Japan systematically integrates cybersecurity and information warfare measures, legislative frameworks, and proactive initiatives to fortify critical infrastructure and secure sensitive data. The literature review addresses the major policies and interventions by examining Japan's 2021 Cybersecurity Strategy, outlining the government's approach to addressing contemporary threats. The methodology employs a mixed research approach, incorporating document analysis and expert interviews of cybersecurity incidents. The analysis section will dissect secondary sources, resulting in a conclusion synthesizing key findings, academic contributions, and implications for policymakers, academics, and practitioners in cybersecurity and national security, aligning with the Cybersecurity Integration Framework (CIF) theoretical framework. The CIF model is used to assess the extent to which Japan's initiatives effectively reconcile pacifism and defensive cybersecurity measures and incorporates Pacifist Elements, Proactive Elements, Adaptability, and Integrated Analysis in its evaluation. The thesis contributes to a detailed understanding of Japan's cybersecurity strategies, highlighting the integration of information warfare, the impact of historical pacifism, and the effectiveness of legislative frameworks.31 0Item Restricted The Role of Cultural Diplomacy in Enhancing Interdependence Between Tourists and Local Communities and its Impact on the Tourism’s Volume(Tokai University, 2024-01-20) Alrajhi, Yara; Takato, OzawaThis research paper delves into the intricate relationship between cultural diplomacy, tourism, and local communities, focusing specifically on Saudi Arabia as a case study. The primary objective is to analyze how cultural diplomacy initiatives contribute to fostering interdependence between tourists and local communities, consequently influencing tourism volume and experience. The paper begins by providing an overview of the burgeoning tourism sector in the Gulf Cooperation Council (GCC) countries, with Saudi Arabia emerging as a prominent player in the region. It explores the evolving dynamics of tourism and cultural diplomacy, highlighting the interconnectedness between these two realms and their impact on societal, economic, and diplomatic facets. A substantial portion of the research is dedicated to dissecting the concept of tourism diplomacy, emphasizing its pivotal role in shaping perceptions, fostering mutual understanding, and strengthening international relations. Through a critical lens, the study examines various strategies and initiatives employed in cultural diplomacy efforts within Saudi Arabia, assessing their effectiveness in promoting cultural exchange, heritage preservation, and community engagement. Furthermore, the research scrutinizes the intricate nexus between tourism development and local communities, shedding light on the symbiotic relationship that emerges when cultural diplomacy initiatives prioritize community involvement and empowerment. It investigates how such initiatives can lead to economic benefits, social cohesion, and sustainable tourism practices while addressing potential challenges and drawbacks. By conducting a comprehensive analysis and utilizing qualitative and quantitative research methods, this paper offers valuable insights into the multifaceted impact of cultural diplomacy on tourism dynamics within Saudi Arabia. It underscores the significance of fostering interdependence between tourists and local communities as a strategic approach to enhancing the overall tourism experience, promoting cultural heritage, and advancing diplomatic objectives. In conclusion, the research underscores the imperative of adopting holistic and inclusive approaches to cultural diplomacy in the realm of tourism, advocating for collaborative efforts that prioritize mutual benefit, cultural exchange, and sustainable development in the context of Saudi Arabia's tourism landscape.10 0
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