• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.341-341
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• 2009

초전도 케이블의 대용량 전력수송능력을 실계통에 적용하기 위해서는 정상상태 뿐 아니라 계통운용상 발생하는 비정상 상태에 대해서도 안정된 성능을 나타내야 한다. 계통운영시 가장 일반적으로 발생하는 비정상 상태의 하나인 계통불평형부하 상태에서의 초전도 케이블의 특성을 실증적으로 확인하기 위해 한전 고창전력시험센터에서 신뢰성시험을 실시하였다. 삼상 송전계통에서 각 상 도체전류는 각 상의 부하량에 의해 결정이 되므로 과도상태라 해도 상당한 시간동안 도체전류가 불평형일 경우 자기적으로 결합된 차폐층전류의 불평형상태가 발생한다. 차폐층전류는 삼상 순환회로의 중성도체가 존재하지 않는 경우 도체전류와의 차이가 발생하게 되어 자기차폐 실패의 원인이 됨으로서 AC손실 증가요인으로서 영향이 커진다. 본 논문에서는 도체전류의 불평형 상태를 실증적으로 모의 발생시켜 연관된 차폐층 순환전류의 형태 및 특성을 검토함으로서 삼상 초전도 케이블의 불평형 부하특성에 대한 연구 진행경과를 요약한다.

• Journal of Korean Society of Transportation
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• v.20 no.7
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• pp.79-85
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• 2002

In this paper, multilevel models are adopted to identify interactions among household members in trip making behaviors. The multilevel approach is a proper methodology to handle samples, which are extracted from a hierarchical structure universe. PSTP dataset is used in developing models and understand proportion of variations among individuals and household. The results of this study show that for activity participation and travel behavior household level variance is more than 1/4 of person level variance and therefore not negligible. The results confirm the importance of multilevel model in travel behavior analysis.

• Journal of Korea Water Resources Association
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• v.49 no.3
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• pp.207-215
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• 2016

In this study, it is analyzed how large scale climate variation has an effect on climate systems over Korea using correlation analysis between climate indices and Intrinsic Mode Functions (IMFs) of precipitation and temperature. For this purpose, the estimated IMFs of precipitation and temperature from the accompanying paper were used. Furthermore, cross correlation coefficients and lag time between climate indices and IMFs were calculated considering periodicities and tendencies. As results, more accurate correlation coefficients were obtained compared with those between climate indices and raw precipitation and temperature data. We found that the Korean climate is closely related with climate variations of $El-Ni{\tilde{n}}o$ in terms of periodicity and its tendency is followed with increasing sea surface temperature due to climate change.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.17 no.1
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• pp.10-18
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• 2006

Objective : The aims of this study were to explore the relations of internet addiction to depression, impulsivity, and obsessive-compulsivity in adolescents. Methods : 1410 high school students (male=611, female=799 : mean age=$16.2{\pm}0.7$) were included in this study. The questionnaire consisted of items on demographic characteristics and internet use pattern. We assessed the level of internet addiction using Young's internet addiction scale (IAS) Barratt impulsiveness scale (BIS) and Maudsley obsessive compulsive inventory (MOCI) were also self-rated. In this study, We defined upper 25% of IAS as 'addiction group' and lower 25% as 'non-addiction group'. Results : The results were as follows ; 1) Male students had significantly higher mean scores on Internet addiction scale than females and there was significantly higher rate of male students in addiction group. 2) The addiction group spent more time for internet use, especially for games than non-addiction group. 3) The addiction group showed significantly higher total scores on BDI, BIS, and MOCI than non-addiction group. 4) Significant associations have been found between the level of internet addiction and depression, impulsivity, and obsessive-compulsivity, respectively. Conclusion : Depression, impulsivity, and obsessive-compulsivity could be significant factors predicting internet addiction. Especially, direct effect of impulsivity could be the most significant to explain internet addiction. Adolescents with high impulsivity may be vulnerable to internet addiction.

• Journal of Oral Medicine and Pain
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• v.30 no.3
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• pp.345-351
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• 2005

The purpose of this double-blind study was to evaluate clinical effects of botulinum toxin type A (BTX-A) injection on myofascial pain syndrome (MPS) involving upper trapezius and compare with those of lidocaine injection. 21 patients presenting with active TrP1 and/or TrP2 in the upper trapezius over 6 months were selected for this study. The subjects were randomly divided into two groups; one group injected with BTX-A (15 unit of $Botox^{(R)}$ / 0.3 ml per trigger point (TrP)) and the other group injected with 0.5% lidocaine (0.3 ml /TrP). The clinical effects were evaluated by VAS and PPT at baseline, 2, 4, 6 and 8 weeks after treatment. BTX-A group showed persistent decrease of VAS values and increase of PPT values following treatment. While there was no significant difference in VAS values between BTX-A and lidocaine groups (p=0.347), there was significant difference in PPT values after treatment between two groups (p=0.000). The subjects received BTX-A showed noticeable improvement in PPT values after treatment, suggesting more reliable effect of BTX-A injection compared with lidocaine injection. The results of this study support that the direct injection of BTX-A to a TrP is an effective and safe treatment for MPS involving upper trapezius.

• The KIPS Transactions:PartC
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• v.17C no.1
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• pp.89-98
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• 2010

In current digital broadcasting systems, GEM(Globally Executable MHP)-based middlewares such as MHP(Multimedia Home Platform), OCAP(OpenCable Application Platform), ACAP(Advanced Common Application Platform) are the norm. Despite much of the common characteristics shared, such as MPEG-2 and DSM-CC(Digital Storage Media-Command and Control) protocols, the information and data structures they need are slightly different, which results in incompatibility issues. In this paper, in line with an effort to develop an integrated DTV middleware, we propose a general-purpose, reconfigurable DSM-CC architecture for supporting various standard GEM-based middlewares without code modifications. First, we identify DSM-CC components that are common and thus can be shared by all GEM-based middlewares. Next, the system is provided with middleware-specific information and data structures in the form of XML. Since the XML information can be parsed dynamically at run time, it can be interchanged either statically or dynamically for a specific target middleware. As for the performance issues, the response time and usage frequency of DSM-CC module highly contribute to the performance of STB(Set-Top-Box). In this paper, we also propose an efficient application cache management strategy and evaluate its performance. The performance result has shown that the cache strategy reflecting user preferences greatly helps to reduce response time for executing application.

• Horticultural Science & Technology
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• v.32 no.5
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• pp.684-693
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• 2014

Abiotic stress conditions such as cold, drought, and salinity trigger physiological and morphological changes and yield loss in plants. Hence, plants adapt to adverse environments by developing tolerance through complex regulation of genes related to various metabolic processes. This study was conducted to construct a coexpression network for multidirectional analysis of salt-stress response genes in Brassica rapa (Chinese cabbage). To construct the coexpression network, we collected KBGP-24K microarray data from the B. rapa EST and microarray database (BrEMD) and performed time-based expression analyses of B. rapa plants. The constructed coexpression network model showed 1,853 nodes, 5,740 edges, and 142 connected components (correlation coefficient > 0.85). On the basis of the significantly expressed genes in the network, we concluded that the development of salt tolerance is closely related to the activation of $Na^+$ transport by reactive oxygen species signaling and the accumulation of proline in Chinese cabbage.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.124-124
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• 2000

다이아몬드에 버금가는 높은 경도뿐만 아니라 높은 화학적 안정성 및 열전도성 등 우수한 물리화학적 특성을 가진 입방정 질화붕소(cubic boron nitride)는 마찰.마모, 전자, 광학 등의 여러 분야에서의 산업적 응용이 크게 기대되는 재료이다. 특히 탄화물형성원소에 대해 안정하여 철계금속의 가공을 위한 공구재료로의 응용 또한 크게 기대된다. 이 때문에 각종의 PVD, CVD 공정을 이용하여 c-BN 박막의 합성에 대한 연구가 광범위하게 진행되어 많은 성공사례들이 보고되고 있다. 그러나 c-BN 박막의 유용성에도 불구하고 아직 실제적인 응용이 이루어지지 못한 것은 c-BN 박막의 증착직후 급격한 박리현상 때문이다. 본 연구에서는 평행자기장을 부가한 ME-ARE(Magnetically Enhanced Activated Reactive Evaporation)법을 이용한 c-BN 박막의 합성에서 적용한 증착공정 인자들의 변화에 따른 박리특성 고찰과 함께 다층박막화 및 제 3원소 혼입 방법을 적용하여 박리특성 향상 정도를 조사하였다. BN 박막합성은 전자총에 의해 증발된 보론과 (질소+아르곤) 플라즈마의 활성화반응증착(Activated Reactive Evaporation)에 의해 이루어졌다. 기존의 ARE 장치와 달리 열음극(got cathode)과 양극(anode) 사이에 평행자기장을 부가하여 플라즈마의 증대시켜 반응효율을 높였다. 합성실험용 모재로는 p-type으로 도핑된 (100) Si웨이퍼를 30$\times$40mmzmrl로 절단 후, 10%로 희석된 완충불산용액에 10분간 침적하여 표면의 산화층을 제거한 후 사용하였다. 박막실험실에서의 주요공정변수는 기판바이어스 전압, discharge 전류, Ar/N2가스유량비이었다. 합성된 박막의 결정성 분석을 FTIR을 이용하였으며, BN 박막의상 및 미세구조관찰을 위해 투과전자현미경(TEM;Philips EM400T) 분석을 병행하였고, 박막의 기계적 물성 평가를 위해 미소경도를 측정하였다. 박리특성의 고찰은 대기중에서의 자발적 박리가 일어나 90%이상의 박리가 진행된 시점까지의 시간을 측정하였고, 증착직후 박막의 잔류응력 변화와 연관하여 고찰해 보았다.

• Korean Journal of Applied Biomechanics
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• v.19 no.1
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• pp.167-177
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• 2009

The purpose of this study was to investigate effect of golf shoe design on kinematic variables during golf swing. Five professional male golfers with shoe size 270mm were recruited for the study. Swing motion was collected using 8 high speed camera motion analysis at a sampling of 180Hz. Kinematic variables were calculated by EVaRT 4.2 software. Driver swing was divided into four events; El(adress), E2(top), E3(impact) and E4(finish). Time, peak velocity, velocity of center of mass, velocity of the foot and ankle angle during Phase 1(El-E2), Phase 2(E2-E3), and Phase 3(E3-E4) were analyzed in order to investigate the relationship between golf shoe design and swing performance. The findings indicated that type C golf shoes would be beneficial for stability and control of movement during address and swing performance. Furthermore, faster speed of golf shoes, center of mass, and both feet were observed with Type C golf shoes. It is expected that golfers with Type C golf Shoes provide greater force as they control the center of mass faster and increase rotational force during impact compared to other golf shoes.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.136-136
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• 2003

카본나노튜브는 상용되는 기존의 센서에 비해 표면적이 넓어 감도가 놀고 응답속도가 빠르다. 또한 나노 스케일의 크기를 가지므로 고직접화를 실현할 수 있으며 기능복구성이 뛰어나 상온동작을 통한 저전력화가 가능하다. 본 실험에서는 아크방전법으로 합성한 카본나노튜브를 가스센서로 제작하여 상온에서 NH$_3$, NO 가스와의 반응 특성을 평가하였다. 또한 origin soot와 이를 정제한 purified CNT를 SEM(주사전자현미경), TEM(투과전자현미경), Raman scattering spectroscopy(라만 산란 분광기)를 통해 재료적 특성을 조사하고 이를 가스 감응 곡선과 연관하여 비교, 분석하였다. 전극에 CNT막을 형성시키기 위해 3g의 N,N dimethylformamide 용액에 CNT 10mg을 분산시킨 후 2시간동안 초음파 처리하였다. 이 용액을 mask를 이용해 전극 위에 막을 형성시킨 후 20$0^{\circ}C$에서 열처리하였다. 이렇게 제조된 origin soot와 purified CNT센서는 flow system을 이용하여 측정하였고 $N_2$분위기 하에서 센서를 안정화시킨 후 측정가스와의 반응을 살펴보았다 센서의 반응속도, 회복속도, 감도 등의 측정결과 origin soot는 NH$_3$ 25ppm에서 20%, purified CNT는 1%의 감도를 보여 20배 높은 감도를 보았다. NO 25ppm의 경우에도 origin soot가 8%, purified CNT는 0.8%의 감도를 보여 10배 높은 감도를 보였다. 이는 탄소입자가 많은 origin soot가 purified CNT 보다 표면적이 넓어 보다 많은 가스 흡착 싸이트를 가지기 때문이다. 하지만 origin soot는 반응시간과 회복속도가 Purified CNT 보다 2배 이상 느려 표면적 증가에 따른 가스 흡착과 탈착 능력이 떨어짐을 알 수 있었다. 또한 CNT와 가스사이의 전하 이동 방향에 따라 NH$_3$는 양의 감도를 NO는 음의 감도를 보였다 이는 전하의 이동 방향에 따라 전하와 캐리어 사이의 결합 및 해리가 일어나게 되고 결국 카본나노튜브 내의 캐리어 수를 증감시킴에 따라 나타나는 현상이다. 이러한 가스의 감도는 농도에 따라 증가하였으며 origin soot를 이용하여 1ppm이하의 NH$_3$ 가스를 검출할 수 있었다.