• ETRI Journal
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• v.26 no.1
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• pp.48-52
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• 2004

In this letter, we consider a new packet scheduling algorithm for an orthogonal frequency division multiplexing access/frequency division duplex (OFDMA/FDD)-based system, e.g., mobile broadband wireless access or high-speed portable internet systems, in which the radio resources of both time and frequency slots are dynamically shared by all users under a proper scheduling policy. Our design objective is to increase the number of non-realtime service (e.g., WWW) users that can be supported in the system, especially when the minimum bit rate requirement is imposed on them. The simulation results show that our proposed algorithm can provide a significant improvement in the average outage probability performance for the NRT service, i.e., significantly increasing the number of NRT users without much compromising of the cell throughput.

• The KIPS Transactions:PartA
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• v.8A no.3
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• pp.201-208
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• 2001

Explosive growth of the Web and the non-uniform characteristics of client requests result in the performance degradation of Web servers, and server cache has been recognized as the solution. We analyzed Web server accessing characteristics-repetition, size, and locality of access. Based on the result, we analyzed the cache removal policies and proposed a prefetch strategy to improve the hit ratio of server caches. In addition, through the trace-driven simulation based on the traces from real Web sites, we showed the performance improvement by our proposal.

• Industrial Engineering and Management Systems
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• v.15 no.4
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• pp.403-431
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• 2016

The objective of this study is to integrate the business, maintenance and production processes of a manufacturing system by incorporating errors. First, the required functions are estimated according to the historical data. The system activities are simulated by Visual SLAM software and the required outputs are obtained. Several outputs including lead times in different dimensions, total cost and production rates are computed through simulation. Finally, data envelopment analysis (DEA) is utilized in order to select the best option between the defined scenarios due to the multi-criteria feature of the problem. This is the first study in which the lead times, cost and production rates are simultaneously considered in the integrated system imposed of business, maintenance and production processes by incorporating errors. In the current study, the major bottlenecks of the system being studied are identified and suggested different strategies to improve the system and make the best decision.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.2
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• pp.771-781
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• 2021

The purpose of this study is to identify major drivers of Myanmar's long-term economic growth and draw implications to implement development policies. This study investigated Myanmar, as the country is the most recently opened economy in Southeast Asia. This study conducted simulation analysis based on scenarios by applying World Bank's Long-Term Growth Model, Penn World Table 9.1, and World Development Indicator data. This study makes extensive use of LTGM and the LTGM-TFP extension to improve the validity of models for data calibration. This study confirms the validity of the model with data calibration and specifies scenarios for simulation analyses by setting the growth trajectory of Vietnam due to common geographical, political, and economic conditions. Main findings include that Myanmar's economic growth rate will continue to fall below 3% in 2040 without proper improvement of growth drivers. The results of this study also provide that total factor productivity growth and female labor participation are key factors for Myanmar's long-term economic growth. This study advises policymakers in Myanmar to strengthen human capital, which is crucial for total factor productivity growth in Myanmar's context and directly affects economic growth. Further, labor market policies to promote female labor participation is important to sustain economic growth.

• Health Policy and Management
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• v.33 no.2
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• pp.166-172
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• 2023

Background: To improve the support low-income individuals' medical expenses, it is necessary to think about ways to enhance the Catastrophic Health Expenditure Support Program. This study proposes expanding support criteria and changing the income standard. Methods: This study conducted simulations using national data from the National Health Insurance Service. Simulations performed for people who have used health services (n=172,764) in 2022 to confirm the Catastrophic Health Expenditure Support Program's size based on changes to the subject selection criteria. Results: As a result of the simulation with expanded criteria, the expected budget was estimated to increase between Korean won (KRW) 13.2 (11.5%) and 138.6 billion (37.4%), and the number of recipients increased between 41,979 (48.9%) and 150,317 (76.1%). The results of the simulation for the change in income criteria (applied to health insurance levels below the 50th percentile) estimated the expected budget to increase between KRW -8.9 (-7.8%) and 55.6 billion (15.0%) and the number of recipients to increase between -8,704 (-10.1%) and 41,693 (21.1%) compared to the current standard. Conclusion: The 2023 Catastrophic Health Expenditure Support Program's criteria were expanded as per the 20th Presidential Office's national agenda to alleviate the burden of medical expenses on the low-income class. In addition, The Catastrophic Health Expenditure Support Program needs to be integrated with other medical expense support policies in the mid- to long-term, and a foundation must be prepared to ensure the consistency of each system.

• Journal of Digital Convergence
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• v.18 no.9
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• pp.191-198
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• 2020

In this study, in order to propose an improvement plan for fire simulation training to improve fire response capability, fire simulation training is conducted for three business facilities, and changes according to whether training materials are used and whether the response time for each response stage is reflected in the training evaluation. The response posture and response ability of the training participants were observed and analyzed. As a result of the analysis, it was analyzed that most of the training participants improved their participation in training, response posture, and response ability when the use of training textbooks and response time for each response stage were reflected in the training evaluation. In the event of a fire simulation training, a number of training materials that can similarly implement the fire situation are used to improve and maintain the fire response capabilities (fire notification and fire report, initial extinguishing, and evacuation) of the training participants, and the target time for each response step. The result was that it can be used as a useful index for improving fire response capability and improving fire simulation training in the future and feedback only when quantitative training evaluation is conducted based on this setting.

• Journal of Digital Convergence
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• v.19 no.6
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• pp.399-408
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• 2021

The purpose of this study was to determine the effects of simulation-based practice and clinical practice on nursing students' critical thinking disposition and nursing process confidence. This study is a quasi-experimental design using the non-equivalent control group pretest-posttest only design, targeting 103, 4th grade(51=control group, 52=experimental group) in the Department of Nursing at D University. The collected data were analyzed using the SPSS/WIN 23.0 program, and the main research results are as follows. Students who experienced simulation-based practice showed significant improvement in critical thinking tendencies(t=-3.28, p=.001) compared to those who experienced clinical practice. There was no significant difference in nursing process confidence (t=-1.78, p=.079), but it was significantly higher in actual application, collaborative contsistency, and nursing contsistency. As a result, There were no significant difference in some, but it was contfirmed that simulation-based practice improved the critical thinking disposition and nursing process confidence in of nursing students. In addition to clinical practice, it is considered necessary to study simulation-based practice using repetitive practice and standardized patients in a free simulation practice environment.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2001.01a
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• pp.59-64
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• 2001

The robot soccer simulation game is a dynamic multi-agent environment. In this paper we suggest a new reinforcement learning approach to each agent's dynamic positioning in such dynamic environment. Reinforcement learning is the machine learning in which an agent learns from indirect, delayed reward an optimal policy to chose sequences of actions that produce the greatest cumulative reward. Therefore the reinforcement learning is different from supervised learning in the sense that there is no presentation of input pairs as training examples. Furthermore, model-free reinforcement learning algorithms like Q-learning do not require defining or learning any models of the surrounding environment. Nevertheless it can learn the optimal policy if the agent can visit every state- action pair infinitely. However, the biggest problem of monolithic reinforcement learning is that its straightforward applications do not successfully scale up to more complex environments due to the intractable large space of states. In order to address this problem. we suggest Adaptive Mediation-based Modular Q-Learning (AMMQL)as an improvement of the existing Modular Q-Learning (MQL). While simple modular Q-learning combines the results from each learning module in a fixed way, AMMQL combines them in a more flexible way by assigning different weight to each module according to its contribution to rewards. Therefore in addition to resolving the problem of large state effectively, AMMQL can show higher adaptability to environmental changes than pure MQL. This paper introduces the concept of AMMQL and presents details of its application into dynamic positioning of robot soccer agents.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.11
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• pp.4268-4289
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• 2020

Advanced traffic signal timing method plays very important role in reducing road congestion and air pollution. Reinforcement learning is considered as superior approach to build traffic light timing scheme by many recent studies. It fulfills real adaptive control by the means of taking real-time traffic information as state, and adjusting traffic light scheme as action. However, existing works behave inefficient in complex intersections and they are lack of feasibility because most of them adopt traffic light scheme whose phase sequence is flexible. To address these issues, a novel adaptive traffic signal timing scheme is proposed. It's based on actor-critic reinforcement learning algorithm, and advanced techniques proximal policy optimization and generalized advantage estimation are integrated. In particular, a new kind of reward function and a simplified form of state representation are carefully defined, and they facilitate to improve the learning efficiency and reduce the computational complexity, respectively. Meanwhile, a fixed phase sequence signal scheme is derived, and constraint on the variations of successive phase durations is introduced, which enhances its feasibility and robustness in field applications. The proposed scheme is verified through field-data-based experiments in both medium and high traffic density scenarios. Simulation results exhibit remarkable improvement in traffic performance as well as the learning efficiency comparing with the existing reinforcement learning-based methods such as 3DQN and DDQN.

• Journal of Digital Convergence
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• v.16 no.5
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• pp.267-276
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• 2018

The purpose of this study was to identify the categories and frequencies of communication of students in nursing simulation using standard patient. Data were collected through questionnaires and video recording of communication process of 41 nursing students in simulation related to pediatric enteritis from March to June, 2017. The data were analyzed the contents and frequencies of completed communication forms by trained researcher based on Interaction Process Analysis. In result, students used communication skills in task area frequently. Communication skills, such as orientation, open question, identification, giving information, opinion, and suggestion, and eye contact, were used frequently. In an uncomfortable atmosphere such as listening to the nursing client's complaints, students showed tension and stiff appearance. Students used high quality communication skills such as empathic understanding and therapeutic touch restrictively. In conclusion, we need education strategies relating to therapeutic communication for nursing professionalism and qualitative improvement of nursing service.