• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.146.1-146.1
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• 2011

석탄가스화복합발전(IGCC)공정에서 가스화기를 거쳐 생성된 합성가스로부터 $CO_2$를 효과적으로 분리/회수하기 위해 가스 고형화법을 제안하였다. 가스 하이드레이트 형성과정에서의 반응특성을 살펴보기 위하여 반응시간에 따른 가스소모량과 기상의 $CO_2$ 조성 변화를 측정하였다. 순수계와 촉진제 첨가계 (TBAB (10, 40 wt%), TBAF (10, 34 wt%), THF (4, 19 wt%))에 대하여 하이드레이트 생성 후의 기상과 하이드레이트상의 $CO_2$ 조성을 측정하였으며, 그 결과 하이드레이트 형성법에 의해 고농도의 $CO_2$가 하이드레이트상에 포집되는 것을 확인하였다. 가스 소모량 측정실험에서는 THF 19.1 wt%를 첨가하였을 때 가장 큰 소모량을 보였으며, TBAF 10 wt%를 첨가하였을 때 가장 적은 가스소모량을 보였다. $CO_2$ 조성 변화 실험에서는 가스 소모량 실험과 마찬가지로 THF 19.1 wt%를 첨가하였을 때 가장 큰 조성변화를 보였다. 이는 THF의 첨가로 인하여 가스 하이드레이트로의 전환율 증가로 많은 양의 $CO_2$ 기체가 하이드레이트 상에 포집되었음을 나타낸다. 속도론적인 측면에서는 모든 실험조건에서 하이드레이트 형성반응이 1시간 이내에 대부분 종결되는 것을 볼 수 있었다. 또한 $^1H$-NMR을 통하여 혼합가스 하이드레이트의 구조적인 분석을 진행하였다. 본 실험에서 얻어진 결과는 가스 하이드레이트 형성법을 이용한 합성가스 분리 공정 개발에 중요한 기초자료가 될 것으로 사료된다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.5B
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• pp.313-320
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• 2012

A hybrid floating structure system combined with pontoon and semi-submersible type modules is proposed. This new system can reduce tensile forces of bottom slabs which could cause fatal damage of concrete floating structures. We performed a parametric study on the dimensions of this new system and investigate the sensitivity of the parameters to the behavior. In order to investigate various cases efficiently, we developed a simple two-step static analysis method for the fluid-structure interaction. An optimum system is derived from the investigation of the analysis results, weights and drafts of the hybrid structure. This study shows that introducing this new system to concrete floating structures is an effective way to reduce the tensile force of the bottm slab of such a floating structure. Also, it was found that when the length of the semi-submersible module is about 15%, the behavior would be optimal in the considered case.

• Journal of Korea Water Resources Association
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• v.46 no.2
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• pp.99-109
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• 2013

Increasing complexity of the basin environments makes it difficult for single decision maker to consider all relevant aspects of problem, and thus the uncertainty of decision making grows. This study attempts to develop an approach to quantify the spatial flood vulnerability of South Korea. Fuzzy TOPSIS is used to calculate individual preference by each group and then three GDM techniques (Borda count method, Condorcet method, and Copeland method) are used to integrate the individual preference. Finally, rankings from Fuzzy TOPSIS, TOPSIS, and GDM are compared with Spearman rank correlation, Kendall rank correlation, and Emond & Mason rank correlation. As a result, the rankings of some areas are dramatically changed by the use of GDM techniques. Because GDM technique in regional vulnerability assessment may cause a significant change in priorities, the model presented in this study should be considered for objective flood vulnerability assessment.

• Journal of Korean Foot and Ankle Society
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• v.18 no.4
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• pp.189-194
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• 2014

Purpose: The purpose of this study was to compare the clinical and radiologic results of arthrodesis between anterior approach and transfibular approach arthrodesis in ankle arthritis. Materials and Methods: There were 61 cases of ankle arthritis treated by anterior or transfibular ankle arthrodesis in our hospital from April 2008 to March 2012. We investigated 29 cases (27 patients) who underwent ankle arthrodesis with an anterior approach (15 cases) and transfibular approach (14 cases), and were followed for over two years. Clinically, American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, pain visual analogue scale (VAS), and subjective satisfaction degrees were evaluated. In addition, ankle coronal and sagittal alignments were evaluated using plain radiographs at 6 and 24 months, postoperatively. Results: Clinically, preoperative mean AOFAS score and VAS was 41.3 and 6.4, and were changed to 58.9 and 3.3 postoperatively in the anterior approach group. In the transfibular approach group, preoperative mean AOFAS score was 36.6 and VAS was 7.1, and they were changed to 54.9 and 3.4 postoperatively. However, no significant differences in the clinical results were observed between the two groups (p=0.297). Duration of attaining union was 8.1 weeks in the anterior approach group and 10.4 weeks in the transfibular approach group. Complications were delayed union in one case, nonunion in three cases, cancellous screw breakage in three cases, and complex regional reflex syndrome in one case. Conclusion: After transfibular ankle arthrodesis as treatment of ankle osteoarthritis, the tendency for valgus angulation of the ankle at the final follow-up was observed and 6.5 mm cancellous screw breakage occurred frequently. Therefore, in order to achieve better stability, it is necessary to use 6.5 mm cannulated screws rather than 6.5 mm cancellous screws for ankle arthrodesis.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.500-500
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• 2022

「물환경보전법」은 2007년의 「수질 및 수생태계 보전에 관한 법률」에서 개정된 법률로 그 목적이 수질과 수생태계로 국한되어 왔다. 하지만 통합물관리 도입으로 인하여 제정된 「물관리기본법」에서는 "국가와 지방자치단체가 물과 관련된 정책을 수립, 시행할 때에는 물순환 과정의 전주기를 고려하여야 한다"고 명시되어 있으며 「물환경보전법」의 물순환관리지표는 수량이 제외되어 물순환 왜곡으로 인한 문제점이 충분히 포함되지 않은 실정이다. 따라서 본 연구에서는 국민들의 안전을 도모하기 위하여 물순환관리지표에 도시유역의 물순환 왜곡으로 인한 수재해 현황을 추가적으로 고려하고자 한다. 수재해 현황은 행정안전부의 자연재해로 인한 최근 10년간 인명피해와 피해액 조사를 바탕으로 가장 심각한 피해를 불러일으킨 폭염과 태풍 및 호우를 고려대상으로 선정하였다. 그 중 도시유역에서의 폭염피해란 불투수면적률이 증가함에 따라 증발산량이 감소하며 발생하는 도심의 열섬현상과 깊은 관계가 있고, 태풍 및 호우피해는 첨두유량의 증가와 도시배수의 연결성에 의하여 발생하는 침수와 깊은 관계가 있기에 이를 본 연구에서의 수량의 대표인자로 결정하였다. 수계 단위의 물순환관리지표와 행정구역 단위의 수재해 현황을 공간적으로 비교하기 위해 면적가중평균법을 이용하여 물순환율과 불투수면적률을 행정구역별로 재척도화를 하였다. 그리고 고려할 요소를 판단하기 위해 행정구역 별 물순환관리지표와 열섬현상, 도시침수를 측정하는 지표의 순위를 매겨 등위상관계수를 계산하였다. 도시침수와 열섬현상을 대표하는 지표 중 물순환율과 상관계수가 낮은 지표부터 물순환관리지표에 포함시켜야 할 요소라고 판단하였으며, 이를 바탕으로 보다 개선된 물순환관리지표를 제안하였다. 기후변화에 따라 현재 수재해 위험성이 더욱 커지고 그의 패턴도 달라지고 있기에 본 연구의 결과를 바탕으로 물순환관리지표가 좀 더 국민들에게 실효성이 있는 평가지표로 개선되기를 기대한다.

• The Korean Journal of Applied Statistics
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• v.26 no.2
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• pp.335-347
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• 2013

There are various types of real world signals. For example, an electrocardiogram(ECG) represents myocardium activities (contraction and relaxation) according to the beating of the heart. ECG can be expressed as the fluctuation of ampere ratings over time. A signal is a composite of various types of signals. An orchestra (which boasts a beautiful melody) consists of a variety of instruments with a unique frequency; subsequently, each sound is combined to form a perfect harmony. Various research on how to to decompose mixed stationary signals have been conducted. In the case of non-stationary signals, there is a limitation to use methodologies for stationary signals. Huang et al. (1998) proposed empirical mode decomposition(EMD) to deal with non-stationarity. EMD provides a data-driven approach to decompose a signal into intrinsic mode functions according to local oscillation through the identification of local extrema. However, due to the repeating process in the construction of envelopes, EMD algorithm is not efficient and not robust to a noise, and its computational complexity tends to increase as the size of a signal grows. In this research, we propose a new method to extract a local oscillation embedded in a signal by utilizing the second derivative.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.3
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• pp.630-637
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• 2018

Harmony search (HS) is a recently developed metaheuristic optimization algorithm. HS is inspired by the process of musical improvisation and repeatedly searches for the optimal solution using three operations: random selection, memory recall (or harmony memory consideration), and pitch adjustment. HS has been applied by many researchers in various fields. The increasing complexity of real-world optimization problems has created enormous challenges for the current technique, and improved techniques of optimization algorithms and HS are required. We propose an improved clustering harmony search (ICHS) that uses a clustering technique to group solutions in harmony memory based on their objective function values. The proposed ICHS performs modified harmony memory consideration in which decision variables of solutions in a high-ranked cluster have higher probability of being selected than those in a low-ranked cluster. The ICHS is demonstrated in various optimization problems, including mathematical benchmark functions and water distribution system pipe design problems. The results show that the proposed ICHS outperforms other improved versions of HS.

• Science of Emotion and Sensibility
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• v.18 no.2
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• pp.65-74
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• 2015

Nowadays, people start to focus on the value of 'Mindfulness' and 'Slowness', instead of the importance of 'Development' and 'Advancement' in their whole life. According to this background, we attempted to find new research opportunities on User Experience(UX) in usage context of 'Erasing'. Through a interdisciplinary literature review on related works regarding the concept of erasing, we tried to understanding the meaning of erasing within the perspective of philosophy, psychology, and human-computer interaction(HCI). We also conducted the contextual inquiry, one of the qualitative research methods to examine the actual usage context and the user's experience, with 79 users who were required to erase something in three usage contexts, including Paper-Eraser condition, Computer-Keyboard condition, and Tablet PC condition. The results indicate that it is important to provide not only effective erasing but also satisfaction for users in the usage-context of erasing. From these attempts, we expect that our findings will be helpful to understand the meaning of the erasing in academic and practical fields.

• The Journal of the Korea Contents Association
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• v.15 no.12
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• pp.459-470
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• 2015

In this study, we have developed a retirement coaching model for effective retirement planning by applying systematic conversation of the coaching technique. A draft of the retirement coaching model was complemented by the validity verification of experts. The retirement coaching model can be summarized as follows. The first step, rapport and empowerment(RE), consists of sharing the image of a happy retirement after establishing a rapport between the coach and the people wanting to prepare for retirement. The second step, target establishment(T), consists of setting the theme and goals of the conversation. The third step, identification(I), consists of developing a retirement plan for achieving the established goals. The fourth step, realization(R), consists of establishing a concrete schedule and a method of retirement planning. The fifth step, evaluation(E), consists of sharing impressions during coaching sessions, which facilitates future action plans.

• The Journal of the Korea Contents Association
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• v.13 no.7
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• pp.473-483
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• 2013

In the 21th century, world citizens have more chances to meet and interact with people from different cultural or ethnic backgrounds than ever before. It is therefore inevitable that multiculturalism has become one of the integral part of music education. Educators in every field should make conscious efforts to provide opportunities and experiences for students so that they can adequately cope with these culturally diverse encounters. This study is to grasp the current state of multicultural education in the teacher education program in Korea and America. Also it is aimed to figure out the current multicultural music course offerings available for undergraduate music education majors at the selected 10 American Universities. It is expected that this study may suggest an idea of multicultural-world music education in teacher education.