797 research outputs found

    Vai trò của nhóm nghiên cứu đối với việc công bố quốc tế trong lĩnh vực khoa học tự nhiên và kỹ thuật

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    Công bố khoa học được xem là một trong những thước đo trình độ phát triển khoa học công nghệ và sức cạnh tranh của mỗi một quốc gia do đó nó luôn là chủ đề gây chú ý đối với toàn xã hội trong những năm gần đây. Nâng cao số lượng và chất lượng nghiên cứu khoa học, công bố quốc tế được xem là một trong những yếu tố quan trọng quyết định đến sự hình thành và phát triển của các nhóm nghiên cứu cũng như quyết định cho sự thành công của các hoạt động khoa học công nghệ của bất kỳ cơ quan tổ chức nghiên cứu, giáo dục nào. Nghiên cứu này được thực hiện nhằm đánh giá vai trò của các nhóm nghiên cứu đối với việc công bố quốc tế riêng trong lĩnh vực khoa học tự nhiên và kỹ thuật

    An Effective Metaheuristic for Multiple Traveling Repairman Problem with Distance Constraints

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    Multiple Traveling Repairman Problem with Distance Constraints (MTRPD) is an extension of the NP-hard Multiple Traveling Repairman Problem. In MTRPD, a fleet of identical vehicles is dispatched to serve a set of customers with the following constraints. First, each vehicle's travel distance is limited by a threshold. Second, each customer must be visited exactly once. Our goal is to find the visiting order that minimizes the sum of waiting times. To solve MTRPD we propose to combine the Insertion Heuristic (IH), Variable Neighborhood Search (VNS), and Tabu Search (TS) algorithms into an effective two-phase metaheuristic that includes a construction phase and an improvement phase. In the former phase, IH is used to create an initial solution. In the latter phase, we use VNS to generate various neighborhoods, while TS is employed to mainly prohibit from getting trapped into cycles. By doing so, our algorithm can support the search to escape local optima. In addition, we introduce a novel neighborhoods’ structure and a constant time operation which are efficient for calculating the cost of each neighboring solution. To show the efficiency of our proposed metaheuristic algorithm, we extensively experiment on benchmark instances. The results show that our algorithm can find the optimal solutions for all instances with up to 50 vertices in a fraction of seconds. Moreover, for instances from 60 to 80 vertices, almost all found solutions fall into the range of 0.9 %-1.1 % of the optimal solutions' lower bounds in a reasonable duration. For instances with a larger number of vertices, the algorithm reaches good-quality solutions fast. Moreover, in a comparison to the state-of-the-art metaheuristics, our proposed algorithm can find better solutions

    Stakeholder engagement in late-stage translation phase 4 research for noncommunicable diseases in low- and middle-income countries : what works and why—the Vietnam experience (UMMS–Vietnam Team)

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    Background: Stakeholder engagement is crucial for conducting high-quality implementation research as well as for the incorporation and adoption of health interventions and policies in the community. Objectives: This study sought to build a mutually rewarding collaboration between stakeholders in Vietnam and investigators in the United States. Methods: A collaboration was established between investigators from several institutions in Vietnam and the University of Massachusetts Medical School that was built on mutual trust, cross-cultural learning, and shared experiences. This collaborative arrangement has led to sustainable stakeholder engagement in Vietnam. We formed a multidisciplinary transnational research team and maintained regular contact both online and in person. We also conducted a needs assessment study, in which several focus group discussions and in-depth interviews of stakeholders in Vietnam were carried out. Results: The formal collaboration between investigators in Vietnam and the University of Massachusetts Medical School began in 2011 and has strengthened over time. The U.S. team provided expertise in study and intervention design, data collection and analysis, and trial implementation, whereas the team in Vietnam brought a deep understanding of local health care delivery systems and expertise in the delivery of health care interventions at the grassroots level. Our initial partnership has now grown to include committed individuals at the government, academic, and community levels including the Vietnam Ministry of Health, key governmental and nongovernmental research institutions and agencies, medical and public health universities, and communities in rural settings. The needs assessment study found that there are important gaps in the delivery of hypertension management practices in many rural communities in Vietnam and that stakeholders are fully engaged in our ongoing, community-based, hypertension-control project. Conclusions: Multiple layers of stakeholders and communities in Vietnam are fully engaged with, and have contributed significantly to, our ongoing hypertension control research project in Northern Vietnam. © 2019 World Heart Federation (Geneva). **Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliate “Huy Nguyen” is provided in this record*

    Power beacon-assisted energy harvesting in a half-duplex communication network under co-channel interference over a Rayleigh fading environment: Energy efficiency and outage probability analysis

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    In this time, energy efficiency (EE), measured in bits per Watt, has been considered as an important emerging metric in energy-constrained wireless communication networks because of their energy shortage. In this paper, we investigate power beacon assisted (PB) energy harvesting (EH) in half-duplex (HD) communication network under co-channel Interferer over Rayleigh fading environment. In this work, we investigate the model system with the time switching (TS) protocol. Firstly, the exact and asymptotic form expressions of the outage probability (OP) are analyzed and derived. Then the system EE is investigated and the influence of the primary system parameters on the system performance. Finally, we verify the correctness of the analytical expressions using Monte Carlo simulation. Finally, we can state that the simulation and analytical results are the same.Web of Science1213art. no. 257

    First Principles Prediction Unveils High-Tc_c Superconductivity in YSc2_2H24_{24} Cage Structures

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    The quest for room-temperature superconductivity has been a long-standing aspiration in the field of materials science, driving extensive research efforts. In this work, we present a novel hydride, YSc2_2H24_{24}, which is stable at high pressure using a crystal structure prediction approach with a fixed composition based on known structures. The discovered material is crystalline in a hexagonal unit cell with space group P6/mmm and has a fastinating structure consisting of two distinct cages: Sc@H24_{24} and Y@H30_{30}. By conducting an extensive numerical investigation of lattice dynamics, electron-phonon coupling, and solving the isotropic Eliashberg equation, we have revealed a significant value of λ\lambda = 2.96 as the underlying factor responsible for the remarkably high critical temperature (Tc_c) of 306-332 K in YSc2_2H24_{24}. As pressure increases, the Tc_c remains above the ambient temperature. Our work has the potential to enhance the existing understanding of high-temperature superconductors, with implications for practical applications. The unique network of these cage-like structures holds great promise for advancing our understanding of high-temperature superconductors, potentially leading to innovative applications

    Advancements, Challenges, and Future Directions in Rainfall-Induced Landslide Prediction: A Comprehensive Review

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    Rainfall-induced landslides threaten lives and properties globally. To address this, researchers have developed various methods and models that forecast the likelihood and behavior of rainfall-induced landslides. These methodologies and models can be broadly classified into three categories: empirical, physical-based, and machine-learning approaches. However, these methods have limitations in terms of data availability, accuracy, and applicability. This paper reviews the current state-of-the-art of rainfall-induced landslide prediction methods, focusing on the methods, models, and challenges involved. The novelty of this study lies in its comprehensive analysis of existing prediction techniques and the identification of their limitations. By synthesizing a vast body of research, it highlights emerging trends and advancements, providing a holistic perspective on the subject matter. The analysis points out that future research opportunities lie in interdisciplinary collaborations, advanced data integration, remote sensing, climate change impact analysis, numerical modeling, real-time monitoring, and machine learning improvements. In conclusion, the prediction of rainfall-induced landslides is a complex and multifaceted challenge, and no single approach is universally superior. Integrating different methods and leveraging emerging technologies offer the best way forward for improving accuracy and reliability in landslide prediction, ultimately enhancing our ability to manage and mitigate this geohazard

    RESEARCH ON FACTORS INFLUENCING THE INTENT TO USE NETFLIX MOVIES IN VIETNAM

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    Abstract The Netflix movies market is steadily growing, especially during the complex COVID-19 pandemic. Consumers, instead of opting for free movie streaming services with potential risks and copyright violations, are choosing to pay for a better experience while emphasizing responsibility for protecting copyrights and supporting authors and producers. This research aims to examine the factors influencing the intent to use Netflix movie streaming services among surveyed individuals, primarily focusing on employees aged 18 to 22 in Vietnam. Participants were surveyed through online and offline questionnaires. The author conducted logistic regression analysis, treating the use of Netflix movies as the dependent variable, with five independent variables sourced from a literature review. Through online and offline survey questionnaires and multivariate regression models, the study identified and concluded the factors influencing employees' intent to use Netflix movie streaming services in Vietnam. Data were quantitatively analyzed using IBM SPSS 20.0. The research results identified five positively influencing factors on the intent to use Netflix movie streaming services: Price perception, Risk perception, Attitude, Ethical awareness, Subjective norms. Among these factors, Price perception had the strongest influence on the intent to use Netflix movies, while the Subjective norms factor was found to be insignificant. Consequently, the article suggests managerial implications for businesses to attract customers and promote the Netflix movies market

    Sex differences in clinical characteristics, hospital management practices, and in-hospital outcomes in patients hospitalized in a vietnamese hospital with a first acute myocardial infarction

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    BACKGROUND: Cardiovascular disease is one of the leading causes of morbidity and mortality in Vietnam. We conducted a pilot study of Hanoi residents hospitalized with acute myocardial infarction (AMI) at the Vietnam National Heart Institute in Hanoi. The objectives of this observational study were to examine sex differences in clinical characteristics, hospital management, in-hospital clinical complications, and mortality in patients hospitalized with an initial AMI. METHODS: The study population consisted of 302 Hanoi residents hospitalized with a first AMI at the largest tertiary care medical center in Hanoi in 2010. RESULTS: The average age of study patients was 66 years and one third were women. Women were older (70 vs. 64 years) and were more likely than men to have had hyperlipidemia previously diagnosed (10% vs. 2%). During hospitalization, women were less likely to have undergone percutaneous coronary intervention (PCI) compared with men (57% vs. 74%), and women were more likely to have developed heart failure compared with men (19% vs. 10%). Women experienced higher in-hospital case-fatality rates (CFRs) than men (13% vs. 4%) and these differences were attenuated after adjustment for age and history of hyperlipidemia (OR: 2.64; 95% CI: 1.01, 6.89), and receipt of PCI during hospitalization (OR: 2.09; 95% CI: 0.77, 5.09). CONCLUSIONS: Our pilot data suggest that among patients hospitalized with a first AMI in Hanoi, women experienced higher in-hospital CFRs than men. Full-scale surveillance of all Hanoi residents hospitalized with AMI at all Hanoi medical centers is needed to confirm these findings. More targeted and timely educational and treatment approaches for women appear warranted
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