• Journal of Construction Engineering and Project Management
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• v.10 no.1
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• pp.16-32
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• 2020

Cost and time control of projects is important in preventing project failure. However, achieving effective cost and time control in practice is often challenging. The challenges of project cost and time control in practice are investigated by carrying out a questionnaire survey on the top 150 construction contractors in the UK followed by in-depth semi-structured interviews of practitioners from 15 construction companies in the country. Quantitative analysis reveals that design change is the most important factor inhibiting the ability of UK contractors from effectively controlling both the cost and time of construction projects. Four of the top five factors inhibiting effective cost control are also the top factors inhibiting effective time control albeit in a different order. These top factors-design changes, inaccurate evaluation of project time/duration, risk and uncertainty, non-performance of subcontractors and nominated suppliers were also found to be endogenous factors to the project. Additionally, qualitative analysis of the interviews reveals 16 key challenges to prevent for effective project cost and time control in practice. These are classified into four categorised based on where they stem from as follows; from the organisation (1. Lack of integration of cost and time during project control, 2. lack of management buy-in, 3. complicated project control systems and processes, 4. lack of a project control training regime); from the construction management/project management approach (5. Lapses in integration of interfaces, 6. project control not being implemented from the early stages of a project, 7. inefficient utilisation and control of labour, 8. limited time devoted to planning how a project will be controlled at the outset); from the client; (9. Excessive authorisation gates, 10. use of adversarial and non-collaborative forms of contracts, 11. communication problems within client set-up, 12. obstructive client representatives) and; from the project team (13. Lack of detailed/complete design, 14. lack of trust among the project partners, 15. limited time devoted to project control on site, 16. non-factual reporting). The study posits that knowledge of these project control inhibiting factors and challenges is the first step at ensuring they are avoided and enable the implementation of a more effective project cost and time control process in practice.

• Journal of Internet Computing and Services
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• v.8 no.1
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• pp.99-113
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• 2007

In the rapidly changing e-business environment, organizations need to share information, process business transactions, and enhance collaborations with relevant entities by taking advantage of the various technologies. However, there are always the security issues that need to be handled in order for the e-business operations to be run efficiently. In this research, we suggest the new security authorization model for safety flexible supporting the needs of e-business (e-marketplace) in an organization. This proposed model provides the scalable of access control policy among multi-domains, and preservation of flexible authorization management in distributed system environments. For servers to take the access control policy and enforcement decisions, we also describe the feasible authorization architecture is concerned with how they might seek advice and guideline from formal access control model.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.2
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• pp.611-627
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• 2017

For enhancing the coverage of wireless networks and increasing the spectrum efficiency, small cell networks (SCNs) are considered to be one of the most prospective schemes. Most of the existing literature on resource allocation among non-cooperative small cell base stations (SBSs) has widely drawn close attention and there are only a small number of the cooperative ideas in SCNs. Based on the motivation, we further investigate the cooperative approach, which is formulated as a coalition formation game with power control algorithm (CFG-PC). First, we formulate the downlink sub-channel resource allocation problem in an SCN as a coalition formation game. Pareto order and utilitarian order are applied to form coalitions respectively. Second, to achieve more availability and efficiency power assignment, we expand and solve the power control using particle swarm optimization (PSO). Finally, with our proposed algorithm, each SBS can cooperatively work and eventually converge to a stable SBS partition. As far as the transmit rate of per SBS and the system rate are concerned respectively, simulation results indicate that our proposed CFG-PC has a significant advantage, relative to a classical coalition formation algorithm and the non-cooperative case.

• Research in Community and Public Health Nursing
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• v.30 no.1
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• pp.57-68
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• 2019

Purpose: This study was performed to determine effects of a structure-centered cooperative learning safety education program based on blended learning for elementary school students. Methods: The study is developed in nonequivalent control group non-synchronized design. The subjects included 24 sixth grade students in the experimental group and 23 sixth grade students in the control group, respectively. To prevent diffusion of the experiment, it was carried out from May 20th to June 24th in 2015 with the control group and the other from August 26th to September 30th in 2015 with the experimental group. It was performed on experimental group after the structure-centered cooperative learning safety education program based on blended learning once a week for 6weeks. Data were analyzed by using descriptive statistics, paired t-test and independent t-test. Results: After the intervention, the experimental group showed significant increases in the self-directed learning attitudes and safety behavior compared to the control group except for the academic self-efficacy. Conclusion: The results indicate that the structure-centered cooperative learning safety education program based on blended learning program is effective in safety education for 6th graders.

• Nuclear Engineering and Technology
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• v.56 no.6
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• pp.1959-1974
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• 2024

Nuclear energy plays a crucial role in energy supply in the 21st century, and more and more Nuclear Power Plants (NPPs) will be in operation to contribute to the development of human society. However, as a typical complex system engineering, the operation and development of NPPs require efficient and stable control methods to ensure the safety and efficiency of nuclear power generation. Reinforcement learning (RL) aims at learning optimal control policies via maximizing discounted long-term rewards. The reward-oriented learning paradigm has witnessed remarkable success in many complex systems, such as wind power systems, electric power systems, coal fire power plants, robotics, etc. In this work, we try to present a systematic review of the applications of RL on these complex systems, from which we believe NPPs can borrow experience and insights. We then conduct a block-by-block investigation on the application scenarios of specific tasks in NPPs and carried out algorithmic research for different situations such as power startup, collaborative control, and emergency handling. Moreover, we discuss the possibilities of further application of RL methods on NPPs and detail the challenges when applying RL methods on NPPs. We hope this work can boost the realization of intelligent NPPs, and contribute to more and more research on how to better integrate RL algorithms into NPPs.

• 한국정보교육학회:학술대회논문집
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• 2010.08a
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• pp.193-197
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• 2010

This study aims to investigate the effects of problem-solving competency of students when they study with digital textbook contents and digital inking in collaborative learning. The experimental group solved the math problems using basic digital textbook contents and digital inking while the control group solved the math problems using basic digital textbook contents alone. The result of analysis and comparison is as follows, the experimental group with basic digital textbook contents and digital inking showed more improved problem-solving competency than that of the control group with basic digital textbook contents alone, the experimental group showed recorded a higher satisfactory level than that of the control group.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.3 no.1
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• pp.53-56
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• 2010

This paper explains a system that is suitable for detecting software error running on multimedia distance control for transportation safety environment. This system consists of an ED, and ES. ED is an agent that detects an error by hooking techniques for multimedia distance education based on IP-USN gateway software stack environment. ES is an agent that is an error sharing system for multimedia distance control based on IP-USN gateway software stack environment. From the perspective of multimedia collaborative environment, an error application becomes another interactive presentation error is shared with participants engaged in a cooperative work.

• Journal of Preventive Medicine and Public Health
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• v.48 no.6
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• pp.265-270
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• 2015

The recent Middle East respiratory syndrome coronavirus (MERS-CoV) outbreak has originated from a failure in the national quarantine system in the Republic of Korea as most basic role of protecting the safety and lives of its citizens. Furthermore, a number of the Korean healthcare system's weaknesses seem to have been completely exposed. The MERS-CoV outbreak can be considered a typical public health crisis in that the public was not only greatly terrorized by the actual fear of the disease, but also experienced a great impact to their daily lives, all in a short period of time. Preparedness for and an appropriate response to a public health crisis require comprehensive systematic public healthcare measures to address risks comprehensively with an all-hazards approach. Consequently, discussion regarding establishment of post-MERS-CoV improvement measures must focus on the total reform of the national quarantine system and strengthening of the public health infrastructure. In addition, the Korea Centers for Disease Control and Prevention must implement specific strategies of action including taking on the role of "control tower" in a public health emergency, training of Field Epidemic Intelligence Service officers, establishment of collaborative governance between central and local governments for infection prevention and control, strengthening the roles and capabilities of community-based public hospitals, and development of nationwide crisis communication methods.

• Journal of Preventive Medicine and Public Health
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• v.41 no.4
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• pp.219-224
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• 2008

Due to heightened concerns regarding possible bioterrorist attacks, the Korea Center for Disease Control and Prevention introduced syndromic surveillance systems, which have been run by emergency departments in hospitals throughout Korea since 2002. These systems are designed to identify illness clusters before diagnoses are confirmed and reported to public health agencies, to mobilize a rapid response, and thereby to reduce morbidity and mortality. The Korea Center for Disease Control and Prevention performed drop-in syndromic surveillance successfully during the World Cup Football Games in 2002, the Universiad games in 2004, and the Asian Pacific Economic Cooperation meeting in 2005. In addition, sustainable syndromic surveillance system involving the collaborative efforts of 125 sentinel hospitals has been in operation nationwide since 2002. Because active data collection can bias decisions a physician makes, there is a need to generate an automatic and passive data collection system. Therefore, the Korea Center for Disease Control and Prevention plans to establish computerized automatic data collection systems in the near future. These systems will be used not only fur the early detection of bioterrorism but also for more effective public health responses to disease.

• Journal of Mechanical Science and Technology
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• v.19 no.spc1
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• pp.437-443
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• 2005

Controlling the friction between wheel and rail is direct and very effective measures to improve the curving performances of railway trucks, because the curving performances depend much on friction characteristics. Authors have proposed a method, 'friction control', which utilizes friction modifier ($KELTRACK^{TM}$ HPF) with onboard spraying system. With the method, not only friction coefficient, but also friction characteristics can be controlled as expected. In this study, MBD simulation is very valuable tool to foresee the effect of the control in advance of experiment with real car. And the creep characteristics of wheel/rail contact with the friction modifier takes very important role in the simulation. In this paper, authors propose a theoretical model of wheel/rail contact condition considering the creep characteristics of friction modifier, which is derived the application of principle tribological theories.