• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2000.04a
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• pp.51-56
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• 2000

Demand for new nondestructive evaluations is growing to detect tensile crack growth behavior to predict long term performance of materials and structure in aggressive environments, especially when they are in non-visible area. Acoustic emission technique is well suited to these problems and has drawn a keen interests because of its dynamic detection ability, extreme sensitivity and location of growing defects. In this study, we analysed acoustic emission signals obtained in tensile test of high strength fire resistance steel for frame structure with time frequency analysis methods. The results obtained are summaries as follows ; In the T and TN specimen consisting of ferrite and pearlite grains, most of acoustic emission events were produced near yield point, mainly due to the dislocation activities during the deformation. However, B specimen under $600^{\circ}C$ - 10min had a two peak which was attribute to the presence of martensite phase. The first peak is before yield point the second is after yield point. The sources of second acoustic emission peak were the debonding of martensite-martensite interface and the micro-cracking of brittle martensite phase. In $600^{\circ}C$-30min to $700^{\circ}C$-60min specimens, many signals were observed from area before yield point and counts were decreased after yield point.

• Journal of muscle and joint health
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• v.22 no.3
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• pp.205-218
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• 2015

Purpose: This study was performed to analyze the visiting nurses' job using Developing a curriculum (DACUM). Methods: The DACUM committee with 6 visiting nurses participated in the workshop. In this workshop, the visiting nurses role was defined and their duties and tasks were identified. After content validation via the experts, the pilot test was conducted to 78 nurses. Results: A total of 13 duties and 82 tasks were identified on the DACUM chart which represented the importance, difficulty, and frequency of tasks with alphabet A, B, and C as its higher degree. Regarding duties, 'visiting nursing for high risk group' is the highest, while the lowest was 'public welfare events'. Regarding to tasks, 'discovering a new patient' was the highest, while 'selecting patients and offering medical supplies (nutritional supplement, patch)' was the lowest one. Conclusion: The results showed that visiting nurses working in the visiting health care service center were doing more various duties and tasks than those working according to 'Act on Long-term Care Insurance for the Aged'. The results can be used to develop training programs for visiting nurses and evaluation-scale of their job performance.

• Journal of Agricultural Extension & Community Development
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• v.13 no.2
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• pp.235-249
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• 2006

The objective of this study was to investigate the developmental level of Rural Women Leaders Federation(RWLF) which is one of the major rural women`s association in Korea. The writers designed organization measurement tool based on the reviews on the related studies and gather data from 191 memberships of RWLF through the mail questionnaire and interviews. The major findings were as follows; First, the findings shows us this organization as transition period from identification stage to expanded growth stage in developmental stage of rural women's organizations. Second, this organization focus on share of members decision making and leadership style rather than organization`s vision, strategy or organization level. In other words, this organization focus on human relations aspect rather than internal aspect of organization system. Third, this organization has high level of social evaluation of the organization, even if it has low level of personal compensation or individua's social performance. In conclusion, as long-term view-point, it is needed to help them to promote their self-control of survival ability to improve organization's vision, strategy, differentiation for achieving organizational goals. And it also needed to prepare educational programs to increase Rural Women's leadership capability understanding of organizational characteristics and its operation abilities.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.2
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• pp.179-186
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• 2012

The potential hazards resulting from a low-velocity impact(bird-strike, tool drop, runway debris, etc.) on aircraft structures, such as engine nacelle or leading edges has been a long-term concern to the aircraft industry. Certification authorities require that exposed aircraft components must be tested to prove their capability to withstand low-velocity impact without suffering critical damage. In most of the past research studies unloaded specimens have been used for impact tests, however, in reality it is much more likely that a composite structure is exposed to a certain stress state when it is being impacted, which can have a significant effect on the impact performance. And the radiated impact sound induced by impact is analyzed for the damage detection evaluation. In this study, an investigation was undertaken to evaluate the effect in-plane loading on the impact force and sound of composite laminates numerically.

• Journal of Korean Society of Archives and Records Management
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• v.10 no.2
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• pp.147-170
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• 2010

In this study, national web archiving cases were reviewed and interface types and characteristics were examined. Five interface categories and fourteen evaluation criteria were selected. As for the OASIS, Korean national web archiving project, functions of retrieval interface and user support interface were insufficient and need to be reinforced. Other recommended improvement plans were; diversifications of the subject area of web contents, sharing the web acquisition, make up the special collection, visualization of archiving time and trends, systematic performance of the archiving strategy, and active collaboration with international organization.

• Journal of Environmental Health Sciences
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• v.44 no.1
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• pp.31-43
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• 2018

Objectives: Effective genetic toxicology and molecular biology research techniques and strategies that are highly correlated with the carcinogenic inhalation toxicity test and related research are required. The aim of this study was to maximize the utilization of chemical substances to prevent workers' occupational diseases. Methods: We surveyed the literature, domestic and international references, and the status of relevant domestic and foreign professional organizations. Expert advisory opinions were reflected, and experts were consulted by participating in domestic and overseas academic conferences. Results: The current status of domestic and international genotoxic toxicity evaluation was examined through various documents from related organizations. Cell models for in vitro lung toxicology were investigated and summarized, and the human resources and performance results of genetic toxicity studies and pilot projects were compared and analyzed by holding an advisory meeting. We examined domestic and international genotoxicity guidelines and investigated new test methods for the development of genotoxicity and carcinogenicity. Ultimately, we described long-term future predictions, including the implementation of our researchers' recommendations and occupational genetic toxicology forecasts for future worker health protection. Conclusions: This research project aims to establish current genetic toxicology and molecular biology research techniques and strategies that can maximize the linkage with the carcinogenic inhalation toxicity test and research in the future. We expanded the study of genetic toxicity and establish a foundation forgenetic toxicity in accordance with research trends in Korea and abroad.

• Journal of Korea Water Resources Association
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• v.30 no.5
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• pp.527-537
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• 1997

Reliability, resiliency and vulnerability for the risk analysis are mathematically defined as the evaluation standard of risk level to characterize the risk which influences water resources management and optimal reservoir operations. Monthly inflows are synthetically generated by stochastic generation model for a long-term reservoir water budget analysis, and this method is applied to the Dae-Cheong Multipurpose Dam. As a result of study, reliability based on occurrence, time and quantity are derived respectively. Also resiliency, vulnerability and resiliency inc\dices are estimated to evaluate the performance of water supply on reservoir system, and their relationships are evaluated.

• Journal of the Korean Solar Energy Society
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• v.39 no.3
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• pp.81-89
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• 2019

Long-term solar irradiance data are required for reliable performance evaluation and feasibility analysis of solar photovoltaic systems. However, measurement data of the global horizontal irradiance (GHI) are only available for major cities in Korea. Neither the direct normal irradiance (DNI) nor the diffuse horizontal irradiance (DHI) are available, which are also needed to calculate the irradiance on the tilted surface of PV array. It is a simple approach to take advantage of the decomposition model that extracts DNI and DHI from GHI. In this study, we investigate variations of solar PV power estimation due to the choice of decomposition model. The GHI data from Korea Meteorological Administration (KMA) were used and different sets of typical meteorological year (TMY) data using some well-known decomposition models were generated. Then, power outputs with the different TMY data were calculated, and a variation of 3.7% was estimated due to the choice of decomposition model.

• Korean Medical Education Review
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• v.21 no.1
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• pp.31-40
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• 2019

The Dr. LEE Jong-wook-Seoul Project (DLSP) in the Lao People's Democratic Republic (PDR) is a long-term development cooperation initiative aimed at upgrading the medical education capacity at the University of Health Sciences (UHS) in the Lao PDR. Under the project, eight faculty members from UHS were trained at the Seoul National University College of Medicine for a 12-month period during 2010-2011. Using a training-of-trainers model, we estimated the effect of DLSP on the learning outcomes of students, which was measured using the standard test scores of the students. The questionnaire developed by the Medical Education Assessment Consortium in Korea was given to the students and both the percent-correct and standardized scores were examined. The evaluation strategy was to compare the learning outcomes of the students taught by the trainees with those that were not and to compare the medical topics taught by the trainees with other topics. It was found that the first group of trainees in the DLSP was associated with an increase of 1.5 in the percent-correct test scores for basic medicine. While the interpretation requires caution, it is consistent with the view that a training program for faculty members could be effective in improving the teaching capacity of medical schools in developing countries.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.3
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• pp.467-476
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• 2022

The Bank of Korea raised the benchmark interest rate by a quarter percentage point to 1.75 percent per year, and analysts predict that South Korea's policy rate will reach 2.00 percent by the end of calendar year 2022. Furthermore, because market volatility has been significantly increased by a variety of factors, including rising rates, inflation, and market volatility, many investors have struggled to meet their financial objectives or deliver returns. Banks and financial institutions are attempting to provide Robo-Advisors to manage client portfolios without human intervention in this situation. In this regard, determining the best hyper-parameter combination is becoming increasingly important. This study compares some activation functions of the Deep Deterministic Policy Gradient(DDPG) and Twin-delayed Deep Deterministic Policy Gradient (TD3) Algorithms to choose a sequence of actions that maximizes long-term reward. The DDPG and TD3 outperformed its benchmark index, according to the results. One reason for this is that we need to understand the action probabilities in order to choose an action and receive a reward, which we then compare to the state value to determine an advantage. As interest in machine learning has grown and research into deep reinforcement learning has become more active, finding an optimal hyper-parameter combination for DDPG and TD3 has become increasingly important.