• Journal of the Korean Geotechnical Society
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• v.33 no.8
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• pp.17-27
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• 2017

Gangwon province which is located in northeast of Korea is the coldest region where average daily temperature is below zero during winter while the other regions are above zero. However, there have been insufficient researches on the insulation design and the effect of the insulation on the freezing damages, even though freezing damages were reported consistently in the lining of road tunnel during winter. In this study, to investigate the effect of insulations on the reduction of freezing damages, numerical analysis was performed considering geotechnical and meteorological characteristics in Gangwon province during winter. As a result, it was found that thickness of concrete and shotcrete in lining had negligible effect on the freezing depth while the insulation had significant effect on it. In addition, because the freezing depth is greatly affected by the thermal conductivity of the ground behind the lining in the period of cold weather, these effects should be considered in the estimation of the insulation thickness.

• Journal of Yeungnam Medical Science
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• v.11 no.2
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• pp.381-387
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• 1994

Plummer-Vinson syndrome is a clinical entity characterized by dysphagia, iron deficiency anemia, cheilosis, glossitis, and cervical esophageal web, especially in middle aged women. Recently, the authors experienced a case of Plummer-Vinson syndrome. A 53-year-old female was admitted due to intermittent solid food dysphagia for 18 months. She had a 2 years history of iron deficiency anemia. On admission glossitis, fissures at the angle of the mouth, spoon nails, and iron deficiency anemia were noted. Esophagogram and esophagoscopic examination revealed thin walled concentric web at upper esophagus. Esophageal web was succefully teared by endoscopic balloon dilatation with subseguant improvement of dysphagia. Skin manifestations as well as anemia were markedly improved after oral iron replacement therapy.

• Korean Journal of Applied Biomechanics
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• v.16 no.3
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• pp.75-83
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• 2006

The purpose of this study was to investigate steady-state force depression following active muscle shortening in human tibialis anterior muscle during voluntary contractions. Subjects (n = 7; age $24{\sim}39$ years; 7 males) performed isometric reference contractions and isometric-shortening-isometric contractions, using maximal voluntary effort. Force depression was assessed by comparing the steady-state isometric torque produced following active muscle shortening with the purely isometric reference torque obtained at the corresponding joint angle. In order to test for effects of the shortening conditions on the steady-state force depression, the speed of shortening were changed systematically in a random order but balanced design. Ankle dorsiflexion torque and joint angle were continuously measured using a dynamometer. During voluntary contractions, muscle activation of the tibialis anterior and the medical gastrocnemius was recorded using surface electromyography. Force depression during voluntary contractions, with a constant level of muscle activation, was 12 %, on average over all subjects. Force depression was independent of the speeds of shortening ($13.8{\pm}2.9%$, $10.3{\pm}2.6%$ for 15 and 45 deg/sec over 15 deg of shortening, respectively). The results of this study suggest that steady-state force depression is a basic property of voluntarily-contracting human skeletal muscle and has functional implication to human movements.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.4
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• pp.76-82
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• 1998

Sealing an oil-air mixture plays important roles to have an enhanced lubrication for high speed spindle. Current work is emphasized on the investigation of the air jet effect on the protective collar type labyrinth seal. To improve the sealing capability of conventional labyrinth seal, air jet is injected against through the leakage flow. It has a combined geometry of a protective collar type and an air jet type. In this study, both of a numerical analysis by CFD(Computational Fluid Dynamics) and experimental measurements are carried out to verify sealing improvement. Both of the turbulence and the compressible flow model are introduced in CFD analysis. The sealing effect of the leakage clearance and the air jet magnitude are studied for various parameter in the experiment. The results of pressure drop in the experiment match reasonably to those of the simulation by introducing a flow coefficient. Effects of sealing improvement are explained as decreasing of effective leakage clearance by air jetting. Thus, sealing effect is improved by amount of air jetting even though clearance becomes larger.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.625-629
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• 1997

Sealing an oil-air mixture plays important roles to have an enhanced lubrication for high speed spindele. Current work was emphased on the investigation of air jet effect on the protective collar type labyrinth seal. To improve the sealing capability of conventional labyrinth seal,ari jet was injected against through the leakage flow. It has a combined geometry of a protective collar type and an air jet type. In this study, both of a numerical analysis by CFD (Computational Fluid Dynamics) and experimental measureements are carried out of verify sealing improvement. But of the turbulence and the compressible flow model were introduced in CFD analysis. The sealing effect of the leakage clearance and the air jet magnitude were studied for variousparameter in the experiment. The results of pressure drop in the experiment match reasonably to those of the simulation by introducing a flow coefficient. Effects of sealing improvement are explained as decreasing of effective leckage clearance by air jetting. Thus, sealing effect is improved by amount of air jetting even though clearance become larger.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.610-614
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• 1996

Sealing of lubricat-air mixture in the high performance machining conte is one of most the important characteristics to carry out enhanced lubrication. High speed spindle requires non-contact type of sealing mechanism. Evaluating an optimum seal design to minimize leakage is concerned in the aspect of flow control. Effect of geometry and leakage path are evaluated according to variation of sealing geometry, Velocity, pressure, turbulence intensity of profile is calculated to fina more efficient geometry and variables. This offers a methodological way of enhancement seal design for high speed spindle. The working fluid is regarded as two phases that are mixed flow of oil phase and air phase. It is more reasonable to simulate an oil jet or oil mist type high speed spindle lubrication. Turbulence and compressible flow model are used to evaluate a flow characteristic, This paper arranges a geometry of mostly used non-contact type seal and analyzes leakage characteristics to minimize a leakage on the same sealing area.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1987.05a
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• pp.10.1-10
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• 1987

표준청각검사와 자기청력검사는 청력역치의 측정으로 난청의 종류를 구별하고 누가현상유무를 판정하며, 사청검사를 할 수 있는 공통점을 갖고 있다. 그러나 표준청력검사는 동일강도의 음을 부여하는 대신 자기청력검사는 음의 증강 및 감약이 계속되는 음을 부여하는 점이 양자의 상이점이다. 이런 차이로 인해 자기청력검사에는 일과성 역치 상승(temporary threshold shift)현상이 일어나 청력 역치가 높을 수 있다. 양자의 역치차가 각 청력군별로 어느 정도차이가 있는가를 관찰할 목적으로 정상청력군 50명 (100이), 전음성 난청군 41명(50이), 감각신경성 난청군 38명(50이)을 대상으로 표준 및 자기청력검사의 기도측정을 실시하여 양 검사의 차를 구하고 그 결과를 다음과 같이 요약하였다. 1) 정상청력군과 전음성 및 감각신경성 난청군 모두 자기역치가 표준역치 보다 높게 측정되는 경향으로 난청군에서 더욱 높게 측정되었다. 그러나 자기역치가 낮은 예도 많았다. 2) 양 검사의 일치범위를 $\pm$10㏈로 하면 정상 청력군은 94%, 전음성 난청군 85%, 감각신경성 난청군 79%에서 양 검사가 일치하였다. 3) 자기역치에서 표준역치를 추정할 수 있는 범위는 정상군에서는 5~-l0 ㏈, 난청군에서는 5~-15 ㏈ 의 변동폭이었다. 4) 양 검사의 역치차가 $\pm$20 ㏈이상인 예도 많아 양 검사는 서로 독립된 검사라고 생각되었다.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.88-88
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• 2016

최근 우리나라에서 발생한 홍수 중 많은 관심을 불러일으킨 2010년 광화문 일대와 2011년 강남역 일대 홍수의 주요 원인은 하천관리를 통하여 대응해온 지금까지의 홍수와는 달리 도시의 우수배제 기능이 높은 강도의 강우에 대응하지 못한 것으로 분석되고 있다. 도시내부에서 발생한 이 같은 홍수는 도시의 기능에 심각한 영향을 줄 수 있으며, 거주민의 안전과도 밀접하게 연관된다. 본 연구에서는 도시의 기능과 거주민의 안전을 우선적으로 고려한 홍수 취약성평가 인자를 선정하고자 한다. 기존의 여러 홍수취약성 연구들에서는 취약성을 평가함에 있어 피해금액을 기준으로 적용하는 경우가 많이 있다. 장기적인 홍수대응, 완화 정책의 구상에 있어 예상되는 피해금액은 중요한 지표라고 볼 수 있다. 그러나 이 방법으로는 도시에서 발생 가능한 피해를 모두 반영하는데 한계가 있다. 도로, 지하철, 철도 등의 교통수단이 침수되는 경우, 피해회복을 위한 비용뿐만 아니라, 도시기능에 심각한 영향을 주어 도시의 생산성, 안정성에 막대한 피해를 남길 수 있다. 따라서 피해금액의 규모에 대한 접근만으로는 도시에서 발생한 홍수에 의해 피해를 받는 취약요인을 적극적으로 반영할 수 없다. 본 연구에서는 도시홍수 피해양상과 이에 대한 대응 방법 등 홍수의 물리적 위험성 뿐 아니라 홍수와 연관된 사회적인 요인들을 반영한 취약성 평가인자를 구성하기위하여 인자간의 인과관계 등을 고려하여 인자의 범위를 규정하고 델파이 설문조사와 문헌 연구를 통하여 전문가 의견을 수집, 분석하였다. 홍수취약성에 영향을 주는 요인들을 크게 3가지 그룹으로 정리하여 도시구조물, 거주민, 위험요인으로 구분하고 각 항목별로 영향인자을 선정하였다. 결정된 인자는 2011년 홍수피해가 발생한 도림천 유역에 적용하여 홍수취약성 평가를 수행하고자 한다.

• Korean Business Review
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• v.19 no.1
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• pp.223-240
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• 2006

The purpose of this study is to review the current state of the transformational leadership and LMX approach to the study of leadership. Leadership research has witnessed a shift from traditional transactional models to a new genre of theories of transformational and charismatic leadership and LMX. Transformational leadership theories offer the promise of extraordinary individual and organizational outcomes. Leaders motivate followers to perform beyond expected levels by activating higher order needs, fostering a climate of trust, and inducing them to transcend their self-interest for the organization's sake. Numerous investigations point of the robustness of the effects of such leadership on individual and organizational outcomes such as job satisfaction, organizational commitment, and performance. LMX theory suggests that leaders do not use the same style in dealing with all subordinates, but rather develop a different type of relationship or exchange with each subordinate. These relationships range from those that are based strictly on employment contracts to those that are characterized by mutual trust, respect, liking, and reciprocal influence. LMX has been positively related to job satisfaction, productivity, and career progress of managers and negatively related to turnover and employee grievances. In conclusions, effective leaders link achievement of organizational goals to follower fulfillment of self-development goals, with the former advancing the latter.

• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.1
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• pp.76-81
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• 2007

The effect of either low or high intensity four weeks exercise treadmill running on the activation of the extracellular-signal regulated protein kinase (ERK1/2) and the c-Jun N-terminal kinase(JNK) pathways was determined in rat tibialis muscle. Sprague-Dawley rats were assigned to one of three groups: (i) sedentary group(NE; n=10); (ii) low intensity exercise group (8m/min; LIE; n=10); and (iii) high intensity exercise group(28m/min; HIE; n=10). The training regimens were planned so that animals covered the same distance and had similar glycogenutilization for both LIE and HIE exercise sessions. After four weeks exercise, 48 h after the last exercise bout obtained samples. pERK1 increased 1.5 times comparing with the sedentary group in the low intensity group while it increased 11.7 times in high intensity group, in the tibialis of rats. In the low intensity group, pERK2 increased 1.4 times comparing with the sedentary group while it increased 3.3 times in high intensity group. While pJNK1 decreased 0.9 times, comparing with the sedentary group, pJNK2 was increased to 0.5 times in the low intensity group. But in high intensity group, pJNK2 decreased 0.7 times while pJNK1 didn't show any change. In conclusion, Four weeks exercise of different intensities results in tibialis muscle activation of intracellular signal pathways, which may be one mechanism regulating specific adaptations induced by different exercise intensities.