• Steel and Composite Structures
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• 제47권2호
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• pp.167-184
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• 2023

In this study, a new recentering friction device (RFD) to retrofit steel moment frame structures is introduced. The device provides both self-centering and energy dissipation capabilities for the retrofitted structure. A hybrid performance-based seismic design procedure considering multiple limit states is proposed for designing the device and the retrofitted structure. The design of the RFD is achieved by modifying the conventional performance-based seismic design (PBSD) procedure using computational intelligence techniques, namely, genetic algorithm (GA) and artificial neural network (ANN). Numerous nonlinear time-history response analyses (NLTHAs) are conducted on multi-degree of freedom (MDOF) and single-degree of freedom (SDOF) systems to train and validate the ANN to achieve high prediction accuracy. The proposed procedure and the new RFD are assessed using 2D and 3D models globally and locally. Globally, the effectiveness of the proposed device is assessed by conducting NLTHAs to check the maximum inter-story drift ratio (MIDR). Seismic fragilities of the retrofitted models are investigated by constructing fragility curves of the models for different limit states. After that, seismic life cycle cost (LCC) is estimated for the models with and without the retrofit. Locally, the stress concentration at the contact point of the RFD and the existing steel frame is checked being within acceptable limits using finite element modeling (FEM). The RFD showed its effectiveness in minimizing MIDR and eliminating residual drift for low to mid-rise steel frames models tested. GA and ANN proved to be crucial integrated parts in the modified PBSD to achieve the required seismic performance at different limit states with reasonable computational cost. ANN showed a very high prediction accuracy for transformation between MDOF and SDOF systems. Also, the proposed retrofit showed its efficiency in enhancing the seismic fragility and reducing the LCC significantly compared to the un-retrofitted models.

• 한국콘텐츠학회논문지
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• 제21권1호
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• pp.210-226
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• 2021

이 글의 목적은 미국의 흑인 청년감독 라이언 쿠글러의 작품과 영화세계를 분석하는데 있다. 쿠글러 감독은 독립영화에서 출발하여 현재 할리우드에서 활동 중인 흑인 청년감독으로, 자신의 문화정체성을 바탕으로 흑인의 가치관과 내면의식을 영화로 재현하며 미국 '흑인영화'의 계보를 잇고 있는 청년감독이다. 이 글에서는 대표작 <오스카 그랜트의 어떤 하루>(2013), <크리드>(2015), <블랙 팬서>(2018)를 중심으로 그의 작품세계와 영화철학을 분석하고, 당대 미국 사회현실과의 사회맥락적 의미를 규명한다. 이 연구를 통해 쿠글러 감독은 흑인의 정체성과 흑인성(blackness)을 자기반영하는 '흑인영화'의 전통을 충실히 계승하고 있으며, 동시에 할리우드에서 내면화해 온 백인 남성가부장제 이데올로기를 전복하는 21세기 '새로운 할리우드 흑인영화 파워(New Hollywood Black Film Power)'를 상징하는 청년감독임을 확인할 수 있다.

• 천문학회보
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• 제40권1호
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• pp.52.2-52.2
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• 2015

In astronomical observations, stable auto-guiding and accurate target centering capabilities are critical to increase observation efficiency and sensitivity. Recently, Center for the Exploration of the Origin of the Universe (CEOU) has developed SQUEAN (SED camera for QUasars in EArly uNiverse). SQUEAN is installed and had successful observations at the 82 inch Otto Struve Telescope of McDonald Observatory in 2015 February. We have upgraded the existing auto-guiding softwares to KAP82 (KHU Auto-guiding Package for the McDonald 82 inch Telescope). Keeping the original hardware systems and the software algorithms of CAP (CQUEAN Auto-guiding Package), KAP 82 is completely re-written in Visual C++. We developed several center finding algorithms, e.g., 2D-gaussian fitting and weighted mean methods. In this presentation, we compare the auto-guiding performances with these algorithms.

• 한국지진공학회논문집
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• 제20권3호
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• pp.135-143
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• 2016

In this paper, a design concept of post-tensioned precast bridge piers was proposed to improve seismic behavior of the bridge pier. Mild reinforcing bars are placed continuously along the height of the column. Prestressing tendons are also provided to obtain re-centering capability for seismic events. Arrangement of the axial steels to prevent buckling of rebars at plastic hinge region was suggested and enhanced seismic performance was verified by experiments. Moment-curvature analyses were performed to evaluate the effect of effective prestress on seismic behavior after verifying the calculation method by cyclic tests of the precast columns. A real bridge pier was designed to investigate the seismic performance according to different level of effective prestress. Level of effective prestress showed obvious effect on crushing displacement but negligible effect on lateral displacement at fracture of tendons and reinforcements.

• Nuclear Medicine and Molecular Imaging
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• 제40권2호
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• pp.106-112
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• 2006

Tissue hyperplasia is one of the most frequently encountered complications when self-expanding metallic stents are placed in benign non-vascular luminal organ strictures, thus causing restenosis of the lumen. The investigators postulated that ionizing irradiation could be applied to prevent restenosis caused by tissue hyperplasia in non-vascular luminal organs as it reduced coronary or peripheral arterial narrowing successfully. The authors combined $\beta$-irradiation using $^{188}Re-MAG_3$ solution with balloon dilation for animal and clinical studies because this new treatment approach had the advantages such as low penetration depth of $\beta$-ray, self-centering irradiation, and mechanical effect of balloon dilation over using $\gamma$-irradiation with afterloading devices in this article, the concept and mechanism of radioisotope balloon dilation, and animal and clinical studies using radioisotope balloon dilation are reviewed.

• 수산경영론집
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• 제50권2호
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• pp.23-40
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• 2019

The main purpose of this study is to analyze and examine the problems of the law systems of the safety and maintenance of nuclear facilities and to propose the improvements with respect to the related problems especialy focused on safety management of aquatic products. Therefore, the results of the paper would be helpful to build an effective management law system of safety and maintenance of nuclear facilities and fisheries products. The research methods are longitudinal and horizontal studies. This study compares domestic policies with foreign policies of nuclear plants and aquatic products. Using the above methods, examining the current system of nuclear-related laws and regulations, we have found that there exist 13 Acts including "Nuclear Safety Act", etc. Safety laws related on nuclear facilities have seven Acts including "Nuclear Safety Act", "the Act on Physical Protection and Radiological Emergency", "Radioactive waste control Act", "Act on Protective Action Guidelines against Radiation in the Natural Environment", "Special Act on Assistance to the locations of facilities for disposal low and intermediate level radioactive waste", "Korea Institute of Nuclear Safety Act". "Act on Establishment and Operation of the Nuclear Safety and Security Commission". The seven laws are composed of 119 legislations. They have 112 lower statute of eight Presidential Decrees, six Primeministrial Decrees and Ministrial Decrees, 92 administrative rules (orders), 6 legislations of local self-government aself-governing body. The concluded proposals of this paper are as follows. Firstly, we propose that the relationship between the special law and general law should be re-established. Secondly, the terms with respect to law system of safety and maintenance of nuclear plants should be redefined and specified. Thirdly, it is advisable to re-examine and re-establish the Law System for Safety and Maintenance of Nuclear Facilities. and environmental rights like the French Nuclear Safety Legislation. Lastly, inadequate legislation on the aquatic pollution damage should be re-established. It is necessary to ensure sufficient transparency as well as environmental considerations in the policy decisions of the Korean government and legislation of the National Assembly. It is necessary to further study the possibilities of accepting the implications of the French legal system as a legal system in Korea. In conclusion, the safety management of nuclear facilities is not only focused on the secondary industry and the tertiary industry centering on power generation and supply, but also on the primary industry, which is the food of the people. It is necessary to prevent damage to be foreseen. Therefore, it is judged that there should be no harm to the people caused by contaminated marine products even if the "Food Safety Law for Prevention of Radiation Pollution Damage" is enacted.

• Smart Structures and Systems
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• 제8권4호
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• pp.399-412
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• 2011

This study compares the performance of two smart isolation systems that utilize superelastic shape memory alloys (SMAs) for seismic protection of bridges using energy balance concepts. The first isolation system is a SMA/rubber-based isolation system (SRB-IS) and consists of a laminated rubber bearing that decouples the superstructure from the bridge piers and a SMA device that provides additional energy dissipation and re-centering capacity. The second isolation system, named as superelastic-friction base isolator (S-FBI), combines the superelastic SMAs with a flat steel-Teflon bearing rather than a laminated rubber bearing. Seismic energy equations of a bridge structure with SMA-based isolation systems are established by absolute and relative energy balance formulations. Nonlinear time history analyses are performed in order to assess the effectiveness of the isolation systems and to compare their performance. The program RSPMatch 2005 is employed to generate spectrum compatible ground motions that are used in time history analyses of the isolated bridge. Results indicate that SRB-IS produces higher seismic input energy, recoverable energy and base shears as compared to the S-FBI system. Also, it is shown that combining superelastic SMAs with a sliding bearing rather than rubber bearing significantly reduce the amount of the required SMA material.

• Smart Structures and Systems
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• 제7권1호
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• pp.41-57
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• 2011

A deeper understanding of the effectiveness of adopting devices mounting shape memory alloy (SMA) elements in applications targeted to the mitigation of vibrations is pursued via an experimental approach. During a seismic event, less than 1000 loading-unloading cycles of the alloy are required to mitigate the earthquake effects. However, the aging effects during the time of inactivity prior to the oscillations (several decades characterized by the yearly summer-winter temperature wave) should be considered in order to avoid and/or minimize them. In this paper, the results obtained by carrying out, in different laboratories, fatigue tests on SMA specimens are compared and discussed. Furthermore, the effects of seismic events on a steel structure, with and without SMA dampers, are numerically simulated using ANSYS. Under an earthquake excitation, the SMA devices halve the oscillation amplitudes and show re-centering properties. To confirm this result, an experimental campaign is conducted by actually installing the proposed devices on a physical model of the structure and by evaluating their performance under different excitations induced by an actuator.

• 가족자원경영과 정책
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• 제15권4호
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• pp.43-64
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• 2011

This study suggests policies to rearrange the status of Health Family Support Centers, targeting hands-on workers and centering on collected problems and improvements. To attain this aim, the study rearranged the materials investigated in 2009. On this basis, the study suggests the following policies. First, Health Family Support Centers changed into Korean Institute Healthy family which could prepare a means for opinion convergence through base organizations. Thus, it is necessary to establish a Gyeonggi-do wide area Health Family Support Center. Second, space and human resource arrangement, suitable to business, are necessary, and so are stable, secure finances. Third, urban areas, agricultural villages, and fishing villages are distributed across Gyeonggi-do. Thus, the development of specialized business, suitable to Gyeonggi-do, is necessary. Consequently, this study suggests executing obligatory family education (education for engaged couples, education for parents). Fourth, case management models, unique to Health Family Support Centers, have to be developed, as well as unified services related to education, counseling, and cultural businesses. Fifth, the Health Family Support Center has to secure its own status as a hub organization of inter-regional family businesses, has to strengthen its organizational identity, and has to promote suitable business development.

• 한국컴퓨터정보학회논문지
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• 제6권3호
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• pp.113-121
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• 2001

인적 서비스의 질은 서비스산업의 경영성과에 영향을 주는 중요한 요인일 뿐만 아니라 조직체의 존속, 성장, 발전에 절대적 영향을 미치므로, 이에 대한 심층적 연구의 필요성이 대두되고 있다. 특히, 신용협동조합의 경우 직원의 대 조합원 서비스의 질은 현재와 같이 어려운 환경 하에서는 조직의 존속과 성장에 더욱 중요한 요소가 되고 있다. 그러므로, 본 연구는 신용협동조합 직원의 인적 서비스의 질에 영향을 미치는 요인들을 중심으로 하여 이들간의 인과관계를 정립하고. 그 요인들이 미치는 영향력을 중심으로 하여 차후의 연구를 위한 시사점을 제공할 목적으로 수행되었다. 이에 따라 본 연구에서는 기존의 연구결과에서 나타난 문제점을 보완하고. 보다 진전된 연구결과를 도출함으로써 신용협동조합 직원들의 대 조합원 서비스의 질에 대한 향상방안을 제시하였다.