• Nuclear Engineering and Technology
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• 제33권6호
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• pp.638-651
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• 2001

The present study is to assess the applicability of the best-estimate thermal-hydraulic code, MARS 1.4, for the analysis of thermal-hydraulic behavior in PWRs during natural circulation conditions. The code simulates a natural circulation test, BETHSY test 4. la, which was conducted on the integral test facility of BETHSY. The test represented the cooling states of the primary cooling system under single-phase natural circulation, two-phase natural circulation and the reflux condensation mode with conditions corresponding to the residual power, 2% of the rated core power value and 6.8 MPa at the secondary system. Based on MARS 1.4 calculations, the major thermal-hydraulic behaviors during natural circulation are evaluated and the differences between the experimental data and calculated results are identified. The calculated results show generally good behavior with regard to the experimental results; the region of single-phase natural circulation is 100-92% of the initial mass inventory, two-phase natural circulation is 84-63 %, and the reflux condensation mode occurred below 58 %. U-tubes empty and the core uncovery are obtained at 39 % and 34 % of the initial mass inventory, respectively.

• International Journal of Naval Architecture and Ocean Engineering
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• 제3권3호
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• pp.174-180
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• 2011

This paper shows added mass and inertia can be acquired from the pure heaving motion and pure pitching motion respectively. A Vertical Planar Motion Mechanism (VPMM) test for the spheroid-type Unmanned Underwater Vehicle (UUV) was compared with a theoretical calculation and Computational Fluid Dynamics (CFD) analysis in this paper. The VPMM test has been carried out at a towing tank with specially manufactured equipment. The linear equations of motion on the vertical plane were considered for theoretical calculation, and CFD results were obtained by commercial CFD package. The VPMM test results show good agreement with theoretical calculations and the CFD results, so that the applicability of the VPMM equipment for an underwater vehicle can be verified with a sufficient accuracy.

• 한국농촌건축학회논문집
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• 제24권2호
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• pp.45-52
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• 2022

Of the 17,106 domestic reservoirs(as of December 2020), 14,611 are older than 50 years, and these old reservoirs will gradually increase over time. The injection grouting method is most applied to the reinforcement method of the aging reservoir. However, the injection grouting method is not accurate in uniformity and reinforced area. An laboratory model test was conducted to evaluate the applicability of the deep mixing method, which compensated for these shortcomings, as a reservoir reinforcement method. As a result of calculating the hydraulic conductiveity for each method through the model test results, the injection grouting method was calculated as a hydraulic conductiveity value that was about 7.5 times larger than that of the deep mixing method. As a result of measuring the water level change in the laboratory model test, it was found that the water level change decreased in the injection method and deep mixing method compared to the non-reinforcement method. In addition, deep mixing method showed a water level change of about 15% based on 40 hours compared to the injection method, indicating that the water-reducing effect was superior to that of the injection method.

• Wind and Structures
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• 제22권4호
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• pp.477-501
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• 2016

Though hilly topography influences both wind speeds and directions aloft, only the influence on wind speeds, i.e. the speed-up effect, has been thoroughly investigated. Due to the importance of a model showing the spatial variations of wind directions above hilly terrains, it is worthwhile to systematically assess the applicability and limitations of the model describing the influence of hilly topographies on wind directions. Based on wind-tunnel test results, a model, which describes the horizontal and vertical variations of the wind directions separately, has been proposed in a companion paper. CFD (Computational Fluid Dynamics) techniques were employed in the present paper to evaluate the applicability of the proposed model. From the investigation, it has been found that the model is acceptable for describing the vertical variation of wind directions by a shallow hill whose primary-to-secondary axis ratio (aspect ratio) is larger than 1. When the overall hill slope exceeds $20^{\circ}$, the proposed model should be used with caution. When the aspect ratio is less than 1, the proposed model is less accurate in predicting the spatial variation of wind directions in the wake zone in a separated flow. In addition, it has been found that local slope of a hill has significant impact on the applicability of the proposed model. Specifically, the proposed model is only applicable when local slope of a hill varies gradually from 0 (at the hill foot) to the maximum value (at the mid-slope point) and then to 0 (at the hill top).

• 대한치과교정학회지
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• 제47권4호
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• pp.229-237
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• 2017

Objective: The aim of this study was to compare the initial stability as insertion and removal torque and the clinical applicability of novel orthodontic zirconia micro-implants made using a powder injection molding (PIM) technique with those parameters in conventional titanium micro-implants. Methods: Sixty zirconia and 60 titanium micro-implants of similar design (diameter, 1.6 mm; length, 8.0 mm) were inserted perpendicularly in solid polyurethane foam with varying densities of 20 pounds per cubic foot (pcf), 30 pcf, and 40 pcf. Primary stability was measured as maximum insertion torque (MIT) and maximum removal torque (MRT). To investigate clinical applicability, compressive and tensile forces were recorded at 0.01, 0.02, and 0.03 mm displacement of the implants at angles of $0^{\circ}$, $10^{\circ}$, $20^{\circ}$, $30^{\circ}$, and $40^{\circ}$. The biocompatibility of zirconia micro-implants was assessed via an experimental animal study. Results: There were no statistically significant differences between zirconia micro-implants and titanium alloy implants with regard to MIT, MRT, or the amount of movement in the angulated lateral displacement test. As angulation increased, the mean compressive and tensile forces required to displace both types of micro-implants increased substantially at all distances. The average bone-to-implant contact ratio of prototype zirconia micro-implants was $56.88{\pm}6.72%$. Conclusions: Zirconia micro-implants showed initial stability and clinical applicability for diverse orthodontic treatments comparable to that of titanium micro-implants under compressive and tensile forces.

• 한국터널지하공간학회 논문집
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• 제8권4호
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• pp.377-388
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• 2006

구조물은 시공과 더불어 노화 현상이 발생하는데 해당 구조물의 효율적인 사용을 위해서는 주기적인 점검 및 유지보수가 수행되어야 한다. 적절한 유지보수의 시기 및 방법의 결정에 있어서는 사전 점검이 중요한 역할을 한다. 본 연구에서는 터널의 사전점검 자동화를 위한 검측 시스템의 개발을 목표로 하고 있으며 이를 위한 사전단계로 시작품을 제작하였다. 시작품 제작에 앞서 기존의 영상 및 레이저를 기반으로 하는 터널 스캐너를 비교 분석하였으며 초기 단계의 터널 스캐너 시작품을 제작하였다. 레이저 스캐닝 시스템 제작에 앞서 범용의 근거리 측량용 상용 레이저 스캐너를 통하여 레이저 스캐너의 적용성을 확인하였으며 그 결과로부터 레이저 스캐너를 바탕으로 하는 터널 스캐닝 시스템이 제작되었다. 제작된 시스템을 바탕으로 실제 공용중인 여러 형상 및 크기의 터널에 대한 스캐닝이 수행되어 장비의 검증이 이루어 졌다.

• 한국강구조학회 논문집
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• 제26권4호
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• pp.335-348
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• 2014

고강도 강의 경우 재료의 높은 항복비와 모재인성 부족으로 인해 휨 구조부재에 적용하기가 용이하지 않다. 고강도 강 휨재의 가장 큰 문제점 중 하나는 일반 연강접합부와 마찬가지로 보 단부의 취성파단이다. 연강접합부의 경우 부재의 보강 및 보 단부의 용접접근공 상세의 개량을 통하여 국내기준의 특수모멘트골조용 접합상세가 다수 개발된 바 있으나 고강도강 접합부에 대한 적용성 평가는 아직까지 미비한 실정이다. 본 연구는 국내에서 개발된 고강도 강(HSA800)을 적용한 기둥-보 접합부의 적용성 평가를 위한 초기단계의 연구이며 보 단부의 용접접근공 상세에 따른 고강도 강 접합부의 구조성능을 실험 및 해석적 방법을 통하여 고찰하였다.

• 보건교육건강증진학회지
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• 제26권2호
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• pp.49-61
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• 2009

Objectives: The purpose of the study was to test the applicability of the Theory of Planned Behavior(TPB) to Korean adult smokers in order to obtain an enhanced understanding of their smoking-cessation intention and to establish strategies for effective smoking-cessation interventions at the community clinic. Methods: The data came from a survey that was conducted on adult male smokers who visited the smoking-cessation clinic at H community clinic in Korea from January to November in 2006 (N=434). Included in the survey were questions asking core variables and salient belief variables dictated by TPB. A structural equation model was established using TPB and data were analyzed to examine the applicability of the theory to the understanding of the structure of variables leading to intention. Results: The analysis of the structural model revealed that the study model was statistically significant(p<.001), suggesting the high validity of TPB in explaining the structure of the data. Among the relationships in the model, negative behavioral beliefs were not significant(p>.05), and negative control beliefs and subjective norm were significant(p<.05) but not as highly as other variables in the model(p<.001). Conclusion: TPB was useful in understanding smoking-cessation intention of smokers who visited community clinic to stop smoking. More specific strategies for counseling and education need to be developed to enhance attitude and perceived behavioral control (self-efficacy) toward smoking-cessation intention, such as emphasizing health benefits of quitting smoking, and eliciting values and life principles that can help increase the intention to stop smoking.

• Journal of Korean Biological Nursing Science
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• 제25권3호
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• pp.183-204
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• 2023

Purpose: The purpose of this study was to evaluate the applicability of ChatGPT in biological nursing science education. Methods: This study was conducted by entering questions about the field of biological nursing science into ChatGPT versions GPT-3.5 and GPT-4 and evaluating the answers. Three questions each related to microbiology and pharmacology were entered, and the generated content was analyzed to determine its applicability to the field of biological nursing science. The questions were of a level that could be presented to nursing students as written test questions. Results: The answers generated in English had 100.0% accuracy in both GPT-3.5 and GPT-4. For the sentences generated in Korean, the accuracy rate of GPT-3.5 was 62.7%, and that of GPT-4 was 100.0%. The total number of Korean sentences in GPT-3.5 was 51, while the total number of Korean sentences in GPT-4 was 68. Likewise, the total number of English sentences in GPT-3.5 was 70, while the total number of English sentences in GPT-4 was 75. This showed that even for the same Korean or English question, GPT-4 tended to be more detailed than GPT-3.5. Conclusion: This study confirmed the advantages of ChatGPT as a tool to improve understanding of various complex concepts in the field of biological nursing science. However, as the answers were based on data collected up to 2021, a guideline reflecting the most up-to-date information is needed. Further research is needed to develop a reliable and valid scale to evaluate ChatGPT's responses.

• Journal of Information Processing Systems
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• 제8권2호
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• pp.213-240
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• 2012

Safety critical systems, real time systems, and event-based systems have a complex set of events and their own interdependency, which makes them difficult to test ma Safety critic Safety critical systems, real time systems, and event-based systems have a complex set of events and their own interdependency, which makes them difficult to test manually. In order to cut down on costs, save time, and increase reliability, the model based testing approach is the best solution. Such an approach does not require applications or codes prior to generating test cases, so it leads to the early detection of faults, which helps in reducing the development time. Several model-based testing approaches have used different UML models but very few works have been reported to show the generation of test cases that use events. Test cases that use events are an apt choice for these types of systems. However, these works have considered events that happen at a user interface level in a system while other events that happen in a system are not considered. Such works have limited applications in testing the GUI of a system. In this paper, a novel model-based testing approach is presented using business events, state events, and control events that have been captured directly from requirement specifications. The proposed approach documents events in event templates and then builds an event-flow model and a fault model for a system. Test coverage criterion and an algorithm are designed using these models to generate event sequence based test scenarios and test cases. Unlike other event based approaches, our approach is able to detect the proposed faults in a system. A prototype tool is developed to automate and evaluate the applicability of the entire process. Results have shown that the proposed approach and supportive tool is able to successfully derive test scenarios and test cases from the requirement specifications of safety critical systems, real time systems, and event based systems.