SACM - China
Permanent URI for this collectionhttps://drepo.sdl.edu.sa/handle/20.500.14154/9652
Browse
243 results
Search Results
Item Restricted The influence of leadership style on effective communication in project teams - A Case Study on Saudi Arabia Railways Company (SAR)(Saudi Digital Library, 2025) AlShammari, Eman .A; Liu, ShiminIn high-complexity industries such as railway transportation, the success of project teams is closely related to effective leadership and communication. This study examines the influence of leadership styles on communication effectiveness within project teams at Saudi Arabia Railways (SAR). The primary goals of the study are to: (1) identify the impact of leadership styles on communication within SAR project teams, (2) develop methods for measuring communication effectiveness, and (3) propose actionable strategies for improving leadership and communication in SAR’s project-based environment. The research employs a quantitative approach, utilizing a structured survey to collect data from SAR project managers, team leaders, and members. Factor analysis, and correlation tests are applied to evaluate the impact of leadership styles on communication clarity, transparency, and responsiveness. The results indicate that leadership styles - characterized by vision setting, motivation, and trust- building - positively correlate with effective communication, fostering collaboration, and problem- solving. Transactional leadership, while ensuring structure and role clarity, exhibits limitations in encouraging open dialogue and adaptability. Departmental variations further reveal that engineering and operations teams, given their technical nature, exhibit a stronger preference for structured communication, whereas human resources favor more adaptive leadership styles. These insights suggest that a hybrid leadership model—balancing transformational inspiration with transactional discipline—can enhance communication efficiency at SAR. The study contributes to both theoretical and practical perspectives on leadership and communication in project-based organizations, offering recommendations for leadership development programs tailored to SAR’s operational demands. By integrating structured leadership approaches with clear communication strategies, SAR can optimize project team performance, mitigate communication barriers, and align with national infrastructure objectives. Future research may explore the long-term effects of leadership training on communication practices within SAR and similar transportation entities.2 0Item Restricted Microstructural Evolution and Phase Characterization of a Ni-Based Superalloy Under Laser-Assisted Heat Treatment(Saudi Digital Library, 2026) Alotaibi, Fawaz Marzouq S; Wan, ZhenpingThis study investigates the microstructural evolution and mechanical behavior of a Nibased superalloy subjected to combined heat treatment and laser processing. Quantitative analysis of γ′ Ni (Al,Ti) and η (Ni Ti) phase distributions were performed using SEMbased statistical methods. The results show that γ′ precipitates exhibit a fine and uniform distribution with sizes in the range of ~0.05–0.30 µm and a high number density (n ≈ 2916), whereas the η (Ni Ti) phase appears as relatively coarse particles (~0.1–0.6 µm) with lower number density (n ≈ 505). Laser treatment promotes redistribution of γ′ precipitates and suppresses η phase formation, resulting in improved microstructural homogeneity. Mechanical characterization reveals that optimal aging (2 h) yields the highest hardness of ~525 HV at 300 °C, while tensile properties show yield strength in the range of ~10001150 MPa and ultimate tensile strength of ~1300–1500 MPa. The results demonstrate a strong correlation between γ′ refinement and enhanced mechanical performance. These f indings provide a quantitative understanding of phase evolution and establish a microstructure-property relationship for optimizing Ni-based superalloys.5 0Item Restricted Induction, selection, and experimental uses of temperature-sensitive and other conditional mutants of yeast.(Saudi Digital library, 2026) ALSHAQAWI, ALBANDRI; ALSHAQAWI ALBANDRIThe current research aims to investigate luxury tourism in Saudi Arabia through addressing this gap by looking at NEOM as a case study. This study investigates how sustainable luxury tourism can be developed in emerging destinations using NEOM as a case study. It examines the influence of sustainability, technology, luxury value, and branding on tourists‘ perceptions and behavioral intention, to examine NEOM's compliance with Vision 2030, its redefinition of luxury tourism, and the shift in demand from value-centric to higher-valued global tourists. The study adopts a mixed-methods methodology, integrating quantitative and qualitative data. A systematic survey was designed by the researcher. Semi-Structured Interviews were made to investigate perceptions of NEOM‘s luxury, sustainability, innovation brand identity and analyze stakeholder (experts, policymakers & tourism professionals) views. The population of the study were high value tourists both domestically and internationally, tourism professionals and industry stakeholders. The study concluded that through the implementation of a coordinated mix of experience-driven initiatives, transparent communication, and targeted partnerships, NEOM will be able to deepen its resonance with local and global audiences, thus speeding up the conversion of favorable perceptions into concrete engagement, and consolidating its consistency with the goals of Saudi Vision 2030. The study contributed both theoretically and practically to sustainability fields, tourism studies, and urban development.2 0Item Restricted Design and Performance Analysis of a Low Current Hollow Cathode with LaB6 for Electric Propulsion on Satellite(Saudi Digital Library, 2026) Alalyani, Hassan; Zhu, GuoqiangThis research presents the design and experimental validation of a low-power lanthanum hexaboride (LaB₆) hollow cathode for satellite electric propulsion. Hollow cathodes are critical components in ion and Hall-effect thrusters, performing two essential functions: emitting electrons to ionize the propellant gas for plasma generation, and injecting electrons into the exhaust beam to neutralize the positively charged ion plume. Without neutralization, spacecraft charging would destabilize thrust and potentially damage onboard electronics. Conventional hollow cathodes utilize impregnated emitters porous metal structures infused with low-work function chemicals. Although effective, these emitters are highly sensitive to contamination from oxygen or moisture in the propellant, require controlled heating cycles with high power consumption, and exhibit limited durability under frequent on-off cycling required for small satellite station-keeping. LaB₆ is a refractory ceramic with high melting point and superior resistance to contamination, was investigated as an alternative emitter material. The cathode structure, designed using SolidWorks, incorporated a LaB₆ crystal within an emitter cavity approximately 30 mm in length. Critical geometric parameters included orifice diameter, which controls internal pressure and plasma flow, and keeper electrode optimization for electron extraction and internal component shielding. Electro-thermal simulations were conducted at multiple temperatures to characterize emission behavior. At 1300°C, current density distribution across the emitter surface was non uniform with edge current crowding, indicating localized overheating and uneven erosion that would reduce operational lifetime. At 1500°C, strong thermionic emission produced significant space-charge effects, where a dense electron cloud formed near the emitter surface, limiting further emission by opposing the applied electric field. This space-charge-limited regime demonstrated a self-regulating mechanism preventing uncontrolled current increase and thermal runaway. Electron trajectory analysis revealed complex motion influenced by electric and magnetic fields, leading to non-linear paths and localized heat deposition on nearby structures. At 1700°C, the system exhibited stable response reaching steady emission in under one millisecond, with current density sufficient for thruster operation while remaining below levels causing rapid material evaporation. Experimental validation was performed in a vacuum chamber through four design iterations. Initial graphite heater wire exhibited resistance instability at high temperature causing premature burnout. Second iteration employing niobium heater achieved successful plasma ignition but experienced insulation failure due to high-temperature degradation of ceramic insulating properties, particularly at graphite contact interfaces creating unintended conductive paths. Subsequent modifications introduced physical spacing between conductive elements and improved insulation coverage. Final configuration achieved stable plasma plume generation with currents up to 5 A, consistent with simulation predictions. Repeated ignition cycles were successful, demonstrating operational robustness suitable for small satellite applications. Minor ceramic surface degradation indicated areas for material improvement without compromising functionality. The results confirm LaB₆ as a viable emitter material for low-power hollow cathodes, with simulations accurately predicting emission behavior and thermal distribution. Key findings include the necessity of operating temperatures above 1500°C for uniform emission, the self regulating nature of space-charge-limited operation, and the critical importance of high temperature insulation materials and sub-millimeter assembly precision. Future work will focus on improved insulation materials and extended lifetime testing for long-duration space missions15 0Item Restricted The Dual Impact of Sharia Finance and Desert Climate on Construction Project Performance in Saudi Arabia(Saudi Digital Library, 2026) ALZAHRANI, ABDULLAH MOHAMMED; Pin-Chao, LiaoSaudi Arabia’s Vision 2030 mega-projects (e.g., NEOM, The Line) represent the cornerstone of the Kingdom’s economic diversification, yet they routinely encounter cost overruns, schedule delays, and compliance burdens. These projects operate under a dual complexity: a Sharia-compliant financial framework and extreme desert environmental conditions. While financial mechanisms and environmental stressors are known to influence construction performance, prior research has examined them in isolation, producing fragmented and sometimes contradictory findings. Islamic finance promotes fiscal discipline and ethical governance (Aebi et al., 2012), but its procedural compliance costs may offset efficiency. Similarly, climate management policies protect workforce health but impose additional operational constraints (Kjellstrom et al., 2009). This dual context necessitates an integrated investigation to clarify how financial and environmental stress jointly shape project outcomes under Vision 2030 imperatives. The study aims to analyze the interaction between financial stressors (liquidity constraints, profit-and-loss sharing) and environmental stressors (extreme heat, hydration risk, and sandstorms) in shaping compliance costs and project performance. Using a sequential mixed-methods design, quantitative data from 54 industry professionals were examined using Partial Least Squares Structural Equation Modelling (PLS-SEM) to test direct and indirect effects, while qualitative interviews with five senior project managers provided explanatory depth. Compliance Costs and Risks were modeled as a potential mediator linking financial and environmental inputs to overall project outcomes. The PLS-SEM results revealed that liquidity constraints have a significant positive effect on compliance costs (β = 0.442, p = 0.005), underscoring liquidity stress as a central operational challenge in Sharia-compliant project financing. All other hypothesized paths, including those from profit-sharing mechanisms, heat, and sandstorms to project performance, were statistically non-significant. However, qualitative evidence illuminated why these effects might remain undetected: managers employ adaptive responses such as flexible scheduling, hydration protocols, and collaborative financing models that buffer stress rather than transmit it. Leadership trust, cultural resilience, and safety culture emerged as informal but effective mechanisms for maintaining performance amid environmental and financial volatility. Thus, compliance functions not as a mediator but as a buffer, containing stress through adaptive governance and organizational trust. This study bridges a critical research gap by integrating Islamic finance and environmental resilience within a unified performance model. It advances project management theory by reframing compliance as an absorptive rather than transmissive construct and by emphasizing the relational dimensions, trust, leadership, and safety culture, that sustain performance under constraint. Practically, it recommends developing integrated governance frameworks that synchronize liquidity management, Sharia compliance, and adaptive environmental practices as key levers of resilience in the Vision 2030 construction ecosystem. The study focuses specifically on government-financed and bank-financed construction projects in Saudi Arabia, and findings may not be directly generalizable to private sector contexts.25 0Item Restricted Entropy-guided meta-learning defense against data poisoning attacks in blockchain-assisted federated learning(Saudi Digital Library, 2026) Algethami, Waheeb; Guowei, WuFederated Learning (FL) enables decentralized model training but remains vulnerable to data poisoning attacks that degrade the performance of the global model. Existing defenses often assume a trusted server or introduce significant detection and communication overhead, limiting their deployment in practical, trustless environments. To address these limitations, we propose FLEML, a blockchain-enabled secure FL framework with entropy-based anomaly detection and meta-learning-driven aggregation. In FLEML, each client’s model update is first committed to a blockchain through hashed transactions and verified by smart contracts to ensure update provenance and prevent tampering. For robustness, the server computes the entropy of client update distributions to quantify behavioral uncertainty and detect abnormal contributions. A metalearning module then learns an adaptive weighting function over client updates, dynamically adjusting aggregation coefficients to suppress poisoned gradients while preserving benign updates. This jointly optimized entropy-aware reweighting mechanism allows the global model to adapt to evolving client behavior without assuming prior trust. Extensive experiments on MNIST, CIFAR- 10, and FashionMNIST under non-IID settings show that FLEML improves model accuracy over FedAvg by 23.14%, 16.15%, and 18.53% on MNIST, 10.25%, 8.06%, and 14.66% on CIFAR-10, and 1.12%, 8.55%, and 5.19% on FashionMNIST under untargeted, label-flipping, and backdoor attacks, respectively. FLEML further achieves 92% precision in malicious update detection and reduces communication overhead by 30% compared with AntidoteFL on CIFAR-10, demonstrating superior robustness and efficiency in adversarial FL environments.3 0Item Restricted The impact of carbon emission accounting on enterprise cost management and strategic decision-making(University of International Business and Economics, 2025) ALZAHRANI, SARAH; Cao, QianIn the context of the global response to climate change, carbon emission management has become a key part of the sustainable development of enterprises. As an emerging field, carbon emission accounting has a profound impact on the accuracy of enterprise cost accounting, cost control and strategic decision-making. Through four stages: theoretical research, enterprise research, data analysis and comparison, and summary and suggestion, this study selects representative samples of enterprises in different industries in China and Saudi Arabia to deeply analyze the practice of enterprises in the two countries under carbon emission accounting. This paper aims to reveal the general law of the impact of carbon emission accounting on enterprise cost management and strategic decision-making, and provide practical suggestions for enterprises in the two countries to improve the efficiency of cost management and the scientific of strategic decision-making3 0Item Restricted The Impact of Corporate Governance on Risk Management for the Insurance Industry in Saudi Arabia Firms(Saudi Digital Library, 2025) ASSIRI, AMER; Baorong, YuThis study examines the relationship between corporate governance and risk management in the Saudi Arabian insurance sector, focusing on how governance mechanisms influence such key risk dimensions as insurance, credit, and liquidity. Despite significant regulatory reforms, the sector faces persistent challenges, including insufficient board independence, limited diversity, and inadequate risk management expertise, which hinder its ability to achieve sustainable growth and financial stability. The research addresses critical gaps in the literature in particular, the lack of empirical studies on governance and risk management in the Saudi context, the under-exploration of advanced analytical techniques, and the insufficient examination of such governance dynamics as board diversity, CEO characteristics, and risk committee expertise. The study leverages a robust dataset comprising 270 annual reports and 4,620 observations from publicly listed insurance firms in Saudi Arabia, spanning a 10-year period (2014–2023). Advanced machine learning models including generalized linear models, random forests, gradient boosting machines, and deep neural networks are employed to analyze the interplay between governance attributes and risk outcomes. Feature importance analyses, including Shapley additive explanations (SHAP) values and force plots, are used to interpret model predictions and identify the most influential governance factors. These techniques provide granular insights into how individual features, such as board independence, risk committee expertise, and firm characteristics, contribute to risk predictions. Key findings reveal that board independence, risk committee expertise, and composite corporate governance are the most influential factors in mitigating insurance, credit, and liquidity risks. Firms with higher proportions of independent directors and well-qualified risk committees exhibit stronger risk oversight and lower risk exposure. Additionally, such firm characteristics as size, profitability, and leverage play a significant role in shaping risk profiles, while CEO duality and tenure have minimal direct impacts on risk outcomes. The study also highlights the moderate influence of gender diversity on governance effectiveness, although nationality diversity and board shareholding show limited direct effects. The research makes several significant contributions. First, it advances the existing literature by providing empirical evidence on the relationship between governance mechanisms ii and risk management in the Saudi insurance sector a context that has received limited scholarly attention. Second, it offers practical insights for industry stakeholders, emphasizing the importance of strengthening board oversight, enhancing risk committee expertise, and fostering diversity to improve governance frameworks. Third, it provides actionable recommendations for policymakers and regulators to align governance practices with international standards, thus helping ensure the sector’s resilience and sustainable growth. Finally, the study aligns with Saudi Arabia’s Vision 2030 objectives by exploring how governance and risk management practices can support economic diversification, financial stability, and sustainable development. In sum, this thesis bridges critical gaps in the literature and provides a roadmap for enhancing governance and risk management in the Saudi Arabian insurance sector, ensuring its competitiveness and alignment with global best practices. The use of advanced analytical techniques, including SHAP values and force plots, underscores the methodological rigor and practical relevance of the study.19 0Item Restricted Research on Active Vibration Reduction of Wind Tunnel Tail Support Rod Based on BP Neural Network PID Algorithm(Saudi Digital Library, 2024) Alzahrani, Faisal; Shen, XingThe antitumor activity of tallysomycins A and B was determined in five experimental tumor systems in mice. Tallysomycins A and B were highly active against B16 melanoma, sarcoma 180 ascites tumor and Lewis lung carcinoma, and moderately active against P388 leukemia but were without effect on lymphoid leukemia L1210. The antitumor activity of tallysomycin A was 2 to 3 times that of tallysomycin B and 3 to 17 times that of bleomycin. Tallysomycin A was about 1.5 and 4 times more toxic for mice than tallysomycin B and bleomycin, respectively, in terms of subacute LD50 values.7 0Item Restricted DDos Attack Detection Method Based on Information Entropy and Naive Bayes(Saudi Digital Library, 2024) Alshmlan, Abdullah Salem; Songfeng, LuWith the advancement of cloud computing technology, the threshold and cost of using cloud computing are gradually decreasing. Meanwhile, an increasing number of distributed denial of service attacks have shifted to cloud environments, posing a serious threat to the security of the entire cloud network space. These attacks consume a large amount of cloud computing resources and have an impact on the normal use of cloud tenants. In response to the difficulty in detecting DDoS attacks with multiple levels of attacks coexisting in the cloud, and considering the cost of the cloud environment. This article introduces a cloud based DDoS attack detection method, which is based on information entropy and naive Bayesian algorithm. This method detects suspected attack flows by calculating the virtual machine traffic entropy of relevant proxy nodes in the cloud and combining it with naive Bayesian classification methods. Design experiments to compare the effectiveness of other machine learning classification algorithms and traditional information entropy detection methods. In the verification phase, the detection method proposed in this article demonstrated good performance in detecting DDoS attacks of different attack intensities in cloud environments.7 0