• 신재생에너지
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• 제7권2호
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• pp.28-35
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• 2011

Recently, photovoltaic systems have been devolved into much larger systems up to MW-scale. Photovoltaic industry participants give their focus on power generation capability of photovoltaic modules because their benefits can be decided from the amount of generation. The information on long-term performance change of photovoltaic modules helps to estimate the amount of power generation and evaluate the economic cost-benefits. Long-term performance of a PV system has been analyzed with operation data for 12 years from 1999 to 2010. In the first year, the amount of yearly power generation was 57.7 MWh with 13.2% capacity factor. In 2007, the amount of yearly generation was 44.3 MWh with 10.14% capacity factor, and in 2010, the amount was decreased down to 38.1 MWh with 8.7% capacity factor. The result means that long-term capacity factor has been 4.5% decreased for 12 years and that the amount of generation has been decreased 34.0% for 12 years which is 2.8 % per year. The latter capacity factor has been decreased faster than 0.20%, the average rate for 10 years. The performance decrease of the PV system is meant to be accelerated. The decrease of performance and utilization is due to aged deterioration of photovoltaic modules and lowering conversion efficiency of PCS.

• 기본간호학회지
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• 제15권1호
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• pp.14-21
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• 2008

Purpose: Objective Structured Clinical Examination(OSCE) has been used for clinical skill evaluation. This study was done investigate whether there are positive impact educational effects if nursing students are invited to develop OSCE modules. Method: The participants were 63 second-year students in one nursing college. Students were divided into 3 groups; the OSCE module development group(Exp1), traditional study group(Exp2), and control group(Cnt). Students were allocated according to clinical skill test scores to make the 3 groups equal. Exp1 developed OSCE modules, and Exp2 studied using traditional methods. Clinical skill tests and surveys were done to measure self-directed readiness, problem-solving ability, and self-efficacy before and after experimental treatments. Results: Clinical skill test scores increased significantly in all three groups, but Exp1 and Exp2 showed a higher clinical skill test score increment than Cnt. Self-directed readiness scores increased significantly in Exp1, but not in Exp2 and Cnt. Problem-solving ability scores increased significantly in Exp1 compared to Cont. Conclusion: Development of OSCE modules has positive educational effects for participating students in terms of clinical skill tests, self-directed readiness, and problem-solving ability.

• 로봇학회논문지
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• 제14권4호
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• pp.278-284
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• 2019

Legged locomotion has high mobility on irregular surfaces by touching the ground at discrete points. Inspired by the creature's legged locomotion, legged robots have been developed to explore unstructured environments. In this paper, we propose a modular crawler that can easily adjust the number of legs for adapting the environment that the robot should move. One module has a pair of legs, so the number of legs can be adjusted by changing the number of modules. All legs are driven by a single driving motor for simple and compact design, so the driving axle of each module is connected by the universal joint. Universal joints between modules enable the body flexion for steering or overcoming higher obstacles. A prototype of crawler with three modules is built and the driving performance and the effect of module lifting on the ability to overcome obstacles are demonstrated by the experiments.

• 신재생에너지
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• 제17권2호
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• pp.24-31
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• 2021

Renewable energy has become more popular with the increase in the use of solar power. Consequently, the disposal of defective and old solar panels is gradually increasing giving rise to a new problem. Furthermore, the efficiency and power output decreases with aging. Researchers worldwide are engaged in solving this problem by developing eco-module technologies that restore and reuse the solar panels according to the defect types rather than simple disposal. The eco-module technology not only solves the environmental problem, but also has economic advantages, such as extending the module life. Replacement of encapsulants contributes to a major portion of the module maintenance plan, as the degradation of encapsulants accounts for 60% of the problems found in modules over the past years. However, the current International Electrotechnical Commission (IEC) standard testing was designed for the commercialization of solar modules. As the problem caused by long-term use is not considered, this method is not suitable for the quality assurance evaluation of the eco-module. Therefore, to design a new accelerated test, this paper provides an overview of EVA degradation and comparison with the IEC and accelerated tests.

• 4차산업연구
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• 제3권1호
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• pp.13-20
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• 2023

Purpose - By designing a PEF(Personalized Education Feedback) system for real-time prediction of learning achievement and motivation through real-time EEG analysis of learners, this system provides some modules of a personalized adaptive learning system. By applying these modules to e-learning and offline learning, they motivate learners and improve the quality of learning progress and effective learning outcomes can be achieved for immersive self-directed learning Research design, data, and methodology - EEG data were collected simultaneously as the English test was given to the experimenters, and the correlation between the correct answer result and the EEG data was learned with a machine learning algorithm and the predictive model was evaluated.. Result - In model performance evaluation, both artificial neural networks(ANNs) and support vector machines(SVMs) showed high accuracy of more than 91%. Conclusion - This research provides some modules of personalized adaptive learning systems that can more efficiently complete by designing a PEF system for real-time learning achievement prediction and learning motivation through an adaptive learning system based on real-time EEG analysis of learners. The implication of this initial research is to verify hypothetical situations for the development of an adaptive learning system through EEG analysis-based learning achievement prediction.

• Current Optics and Photonics
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• 제7권4호
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• pp.398-407
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• 2023

We explored a method to evaluate imaging performance for the optimal assembly of an endoscopic miniature lens and a sensor constituting an imaging module at the distal end of gastrointestinal endoscopy. For the assembly of the imaging module, the image sensor was precisely located at the focal plane when collimated light passed through the endoscopic lens. As another method, the distance between the lens and sensor was adjusted to obtain the highest focus index from images measured the star chart of the International Organization for Standardization (ISO) standard at various positions. We analyzed the slanted-edge modulation transfer function (MTF), corresponding depth of field, and number of line pairs for MTF 50% and 20% at each working distance within the range of 5-100 mm for imaging modules assembled in different ways. Assembly conditions of the imaging module with better MTF performance were defined for each working distance range of 5-30 mm and 30-100 mm, respectively. In addition to the MTF performance, the focus index of each assembled module was also compared. In summary, we examined the performance of imaging modules assembled with different methods within the suggested working distance and tried to establish the optimal assembly protocol.

• 간호행정학회지
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• 제20권2호
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• pp.227-236
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• 2014

Purpose: This study was designed to develop and evaluate the a web-based simulation program on patient rights education using integrated decision making model into values clarification for nurse students. Methods: The program was designed based on the Aless & Trollip model and Ford, Trygstad-Durland & Nelms's decision model. Focus groups interviews, surveys on learning needs for patient rights, and specialist interviews were used to develop for simulation scenarios and decision making modules. The simulation program was evaluated between May, 2011 and April, 2012 by 30 student nurses using an application of the web-based program evaluation tools by Chung. Results: Simulation content was composed of two scenarios on patient rights: the rights of patients with HIV and the rights of psychiatric patients. It was composed of two decision making modules which were established for value clarifications, behavioral objective formations, problems identifications, option generations, alternatives analysis, and decision evaluations. The simulation program was composed of screens for teacher and learner. The program was positively evaluated with a mean score of $3.14{\pm}0.33$. Conclusion: These study results make an important contribution to the application of educational simulation programs for nurse students' behavior and their decision making ability in protecting the patient rights.

• Current Photovoltaic Research
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• 제6권2호
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• pp.62-67
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• 2018

Multi-wire busbar-type bifacial n-type Si solar cells have been used for the fabrication of monofacial and bifacial photovoltaic (PV) module, where bifacial module was equipped with transparent backsheet while monofacial module was prepared using white backsheet. The comparison of six-day accumulated power production obtained from outdoor test under gray cement ground conditions using 60cell monofacial and bifacial PV modules suggested the bifacial gain of over 20% could be achieved. Furthermore, the outdoor evaluation tests of bifacial modules with different ground conditions such as cement (reference), green paint, white paint and green artificial grass, were performed. It turned out white paint showed the best albedo and thus the highest power production, while green paint and artificial grass showed less power generation than cement ground.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1115-1119
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• 2005

The paper proposes the elastic modulus evaluation technique of a cantilever beam by vibration analysis based on time-average electronic speckle pattern interferometry (TA-ESPI) with non-contact and nondestructive and Euler-Bernoulli equation. General approaches for the measurement of elastic modulus of thin film are Nano indentation test, Bulge test and Micro-tensile test and so on. They each have strength and weakness in the preparation of test specimen and the analysis of experimental result. ESPI has been developed as a common measurement method for vibration mode visualization and surface displacement. Whole-field vibration mode shape (surface displacement distribution) at a resonance frequency can be visualized by ESPI. And the maximum surface displacement distribution from ESPI is a clue to find the resonance frequency at each vibration mode shape. And the elastic modules of test material can be easily estimated from the measured resonance frequency and Euler-Bernoulli equation. The TA-ESPI vibration analysis technique is able to give the elastic modulus of materials through the simple processing of preparation and analysis.

• 한국산학기술학회논문지
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• 제15권9호
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• pp.5652-5659
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• 2014

소프트웨어를 구성하는 모듈들은 각 모듈에 주어지는 업무들이 동시에 처리될 수 있도록 멀티태스킹이 가능하도록 개발되며, 또한 처리중인 업무들은 완전처리된 업무들과 처리중 모듈고장으로 완전처리 되지 않는 불완전 처리업무로 세분화한다. 이러한 경우 여러 모듈에 동시에 업무가 주어졌을 때, Farlie [11]의 결합확률분포를 기반으로 모듈간의 의존성을 고려하여 업무의 완전처리확률을 평가할 수 있는 모형을 제안하며, 이를 통하여 모듈의존성 모수 값이 커질수록 소프트웨어에 주어진 업무의 완전처리확률은 점점 커짐을 보이고자 한다.