• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.10
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• pp.3867-3886
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• 2015

This article investigates the problem of opportunistic spectrum access in dynamic environment, in which the signal-to-noise ratio (SNR) is time-varying. Different from existing work on continuous feedback, we consider more practical scenarios in which the transmitter receives an Acknowledgment (ACK) if the received SNR is larger than the required threshold, and otherwise a Non-Acknowledgment (NACK). That is, the feedback is discrete. Several applications with different threshold values are also considered in this work. The channel selection problem is formulated as a non-cooperative game, and subsequently it is proved to be a potential game, which has at least one pure strategy Nash equilibrium. Following this, a multi-agent Q-learning algorithm is proposed to converge to Nash equilibria of the game. Furthermore, opportunistic spectrum access with multiple discrete feedbacks is also investigated. Finally, the simulation results verify that the proposed multi-agent Q-learning algorithm is applicable to both situations with binary feedback and multiple discrete feedbacks.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1285-1293
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• 2008

Locking sheet is to display the contents of interlocking equipment for safe train drive in stations. It is being used as a basic information for interlocking equipment and for route control condition and the discussion for train operation between related parties. In spite of importance of this, there was no other way except depending on the work by hands from each stage(drawing, examination, discussion, approval) due to non-existing any tool. It is written it takes 30days from drawing to approval by procedures. However, it is required over the days in real time due to argument of each party. Furthermore on drawing of locking sheet, special conditions applied in accordance with situations of each station occasionally are different depending on the person in charge. Therefore, it is urgent to make up Logic Tree to accept special conditions of all stations. Automation Program for Drawing and Examination of Locking Sheet is to improve inefficient interlocking operation which was operated by hands in accordance with custom as automated system. The target of this program is to minimize the processing time and potential errors by personal work and set up standards for Logic Tree of special condition.

• Journal of Korean Academy of Nursing
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• v.51 no.4
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• pp.454-464
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• 2021

Purpose: This study aimed to identify the level of complete knowledge about hand hygiene indications among nurses working at integrated nursing care service wards. Methods: A total of 127 nurses in eight integrated nursing care service wards completed structured sheets while observing a video based on six scenarios developed by the research team. Complete knowledge level was calculated as the percentage (%) of participants who responded correctly to all questions among participants. Complete knowledge levels according to the scenarios were calculated and compared according to general characteristics using the chi-squared test or Wilcoxon rank-sum test. Results: The complete knowledge level for each scenario ranged from 7.9% (scenario 6) to 42.5% (scenarios 4 and 5), and no one had complete knowledge of all scenarios. Only 3.1% of participants demonstrated complete knowledge in more than four scenarios, and 26.0% had complete knowledge of four or more hand hygiene moments. Complete knowledge level per scenario did not differ depending on work experience at hospitals and study wards, or prior hand hygiene training in the last year. Conclusion: As the complete knowledge level regarding hand hygiene moment is very low, it is suggested that regular hand hygiene training should be provided to nurses using video media that reflect real nursing tasks. Thus, they can acquire complete knowledge of when hand hygiene is needed or not during complex nursing work situations.

• The Southeast Asian review
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• v.21 no.1
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• pp.185-216
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• 2011

This work shows dynamism of empathy which Thailand experienced while its monarchy was replaced by democracy with conflicts and harmony. In this work, two imaginary protagonists are put into the most important period in Thai history, from the political reform of the absolute monarchy in 1932 up to Black May in 1992, for 60 years. With the writer's imagination, they are actualized into the historically important situations with reality. One of them is Yeoy, a dissident and the other is a police officer, a concenter, who chases after him. In this dissertation, empathy is analyzed which the characters feel about real incidents in their country through trust and doubt, hope and anger. This research on emotional circumstance is all about figuring out the direction for harmony and coexistance. Thailand needs a powerful leader who deals with swiftly changing worldwide affairs and domestically economic matters. Even if their leader has the same destination to get to, their approach to it is different from each other. Therefore, conflicts come out and misunderstanding makes situation worse. Public sympathy among Thai is that Thailand contribute to global mutual prosperity, by which Thailand becomes a powerful and influential state in making the world harmonious and prosperous.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.23 no.6
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• pp.57-73
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• 2020

A study was conducted to present the criteria for evaluating the revegetation method of the slope of the expressway. The results of comparative analysis between 2019-2020 field survey and existing research data (2015-2016) are as follows. Soil is a very important factor at the beginning of revegetation work. However, after the plant has settled, the importance of the soil composition diminishes. Among the plants used, the number of plants sown at the beginning gradually decreases. And it changes as it competes with invading plants. Among the plants used for sowing, it was found to affect the vegetation composition in the order of exotic grass > native herb and wildflower > native tree. Plant coverage is continuously evaluated as an important factor regardless of the time. The vegetation structure on the slope will change continuously over time. New items need to be evaluated in situations where a lot of time has elapsed since the application of revegetation work. It is desirable to use the current evaluation standard only to perform the evaluation within 1 to 2 years. In the long run, it is necessary to establish a new evaluation standard that adjusts the weights of each item.

• Safety and Health at Work
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• v.12 no.1
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• pp.10-19
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• 2021

Background: Traditional safety concept, which is called Safety-I, and its relevant methods and models have much contributed toward enhancing the safety of industrial systems. However, they have proved insufficient to be applied to complex socio-technical systems. As an alternative, Safety-II and resilience engineering have emerged and gained much attention for the last two decades. However, it seems that safety professionals have still difficulty understanding their fundamental concepts and methods. Accordingly, it is necessary to offer an introductory guide to them that helps safety professionals grasp them correctly in consideration of their current practices. Methods: This article firstly explains the limitations of Safety-I and how Safety-II can resolve them from the four points of view. Next, the core concepts of resilience engineering and Functional Resonance Analysis Method are described. Results: Workers' performance adjustment and performance variability due to it should be the basis for understanding human-related accidents in socio-technical systems. It should be acknowledged that successful and failed work performance have the same causes. However, they are not well considered in the traditional safety concept; in contrast, Safety-II and resilience engineering have conceptual bases and practical approaches to reflect them systematically. Conclusion: It is necessary to move from a find-and-fix and reactive approach to a proactive approach to safety management. Safety-II and resilience engineering give a set of useful concepts and methods for proactive safety management. However, if necessary, Safety-I methods need to be properly used for situations where they can still be useful as well.

• Journal of Korean Library and Information Science Society
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• v.53 no.4
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• pp.163-188
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• 2022

This study set out to examine the actual management of 21 small libraries in the Jeju region and search for their vitalization plans based on it with a survey among practitioners. For these purposes, the investigator examined the overall real conditions of small libraries in their management and work situations covering their service hours, program management, volunteer activities, facility expansion, exchanges with common public libraries, work-related education, job priorities, promotional activities, and service for vitalization. Based on findings, the study proposed to induce local residents' interest in small libraries, expand reading culture program, secure professionalism of management manpower, recruit more management manpower, expand budgets for the management of a small library, establish a set of criteria for the expenses of management manpower, build a support center for small libraries.

• 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.

• IEMEK Journal of Embedded Systems and Applications
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• v.19 no.6
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• pp.307-312
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• 2024

In order to solve problems such as data collection and expensive labeling work, we proposed an image segmentation model using semi-supervised and unsupervised learning methods. Since semi-supervised learning is used, high performance can be achieved even in situations with little ground truth. The proposed model consists of a segmentation module and a cluster module. The Segment Anything Model (SAM) is used for the segmentation module. The cluster module uses the k-means clustering algorithm, a representative method of unsupervised learning, to determine whether components belong to the same class within the microbial image. Finally, by configuring a user interface, the system was created to return all objects and corresponding components belonging to the same cluster when the user selects an element that wants to be divided. Both the segmentation module and the cluster module can use semi-supervised or unsupervised learning to reduce the cost of work such as data collection and labeling, which has been a problem with the existing image segmentation model.

• Journal of Practical Engineering Education
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• v.16 no.2
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• pp.241-249
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• 2024

This study was conducted to identify job stress, nursing work environment, and turnover intention for nurses at COVID-19 dedicated hospital, and to identify factors influencing turnover intention. From September 1 to September 27, 2022, 144 nurses at a COVID-19 dedicated hospital in the I area were collected. The collected data used the SPSS Statistics 23.0 program. As a result of the study, the intention to turnover according to general characteristics showed significant differences in work experience (F=11.20, p<.001), and by position (F=4.09, p=.009). In addition, turnover intention showed a significant correlation with job stress (r=.561, p<.001) and nursing work environment (r=-.382, p<.001). The factors influencing turnover intention were job stress (β=.46, p<.001), work experience of more than 11 years (β=.34, p<.001), work experience of 3-10 years (β=.20, p=.022), nursing work environment (β=-.22, p=.001), and 43.9% of explanatory power. Accordingly, in order to reduce the intention to turnover of nurses at hospitals dedicated to COVID-19, it is necessary to create measures to reduce job stress and an efficient nursing work environment considering the characteristics of work by career in infectious disease situations.