• Journal of Korean Society of Coastal and Ocean Engineers
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• v.5 no.2
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• pp.66-75
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• 1993

Hydraulic experiments were performed in order to gain an insight into the quantitative differences between the perforated wall caisson and its solid wall counterpart in the local pressure distribution and caisson stability. The results showed that the wave forces acting on local walls were smaller in the perforated wall caisson than in the solid wall caisson. For the caisson stability, the critical weights of the perforated wall caisson also turned out to be smaller than those of the solid wall caisson. The Phenomenon was attributed to the dual effects inherent to the perforated wall caisson, which are the decrease of total horizontal force and the phase difference between the total horizontal and vertical forces.

• Journal of the Korean Geotechnical Society
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• v.24 no.3
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• pp.5-11
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• 2008

This paper pertains to the incorporation of a genetic algorithm methodology for determining the critical slip surface and the corresponding factor of safety of soil slopes using inclined slice method. The analysis is formulated as a constrained optimization problem to solve the nonlinear equilibrium equations and finding the factor of safety and the critical slip surface. The sensitivity of GA optimization method is presented in terms of development of failure surface. Example problem is presented to demonstrate the efficiencies of the genetic algorithm approach. The results obtained by this method are compared with other traditional optimization technique.

• Proceedings of the KSEG Conference
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• 2005.04a
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• pp.261-268
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• 2005

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.6C
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• pp.321-329
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• 2009

Laboratory compressive test was conducted on 6 different types of rock in order to investigate the characteristic of critical strain under uniaxial and triaxial stress condition. The results of uniaxial compressive test mostly ranged within 1~100MPa, the critical strain was also located between 0.1~1.0%. Therefore the results distributed within the upper and lower boundary proposed by Sakurai (1982). And the failure/critical strain ratio (${\varepsilon}_f/{\varepsilon}_0$) showed between 1.0~1.8 value depending on the uniaxial compressive strength. The results of critical strain by triaxial compressive test showed below 0.8% value for all test, the M value calculated from uniaxial and triaxial compressive test results ranged 1.0~8.0 for most of rock specimens. It is concluded that failure strain (${\varepsilon}_{f3}$) of rock mass, which is in triaxial stress condition is larger than the results of uniaxial stress condition (${\varepsilon}_{f1}$) by 1.0~8.0 times and value showed 1.0~1.8 larger value than critical strain (${\varepsilon}_{01}$). Therefore it is a conservative way for rock tunnel to use critical strain (${\varepsilon}_{01}$) calculated from a uniaxial compressive strength on tunnel displacement monitoring.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04c
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• pp.301-303
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• 2003

기존의 아이디와 패스워드를 이용한 사용자 인증방식의 문제점 및 한계를 해결하기 위하여 생체인식 기술 (Biometric technology)이 연구되었다. 하지만 단일 생체인식 기술은 오인식률(False Acceptance Rate), 오거부율(False Rejection Rate)등의 문제점을 가지고있다. 최근에 단일 생체인식 기술의 한계를 극복하고 사용자 인증 성능 향상과 신뢰도를 높이기 위하여 다중 생체 인식(Multi-modal biometrics)에 관한 연구개발이 활발하다. 이 논문은 지문인식과 얼굴인식 기술을 활용하여 사용자 인증을 수행함으로써 단일 시스템에서 발생하는 한계점을 극복함과 동시에 좀더 안정적인 사용자 인증이 가능한 방법을 제시한다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2002.04a
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• pp.28-28
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• 2002

가스터빈 엔진을 운용하는 데 있어서 가/감속율을 크게 하면 엔진성능 천이 시간은 짧으나 압축기에서의 서지나 터빈 입구온도의 급격한 상승이 발생할 수 있으며 가/감속율을 작게 하면 엔진은 안정적이나 천이시간이 길어지게 되어 결과적으로 엔진의 동적 응답성이 나빠지게 된다. 또한 압축기에서 발생할 수 있는 서지를 방지하기 위하여 압축기 서지 마진이 l0%∼20%인 서지 한계선(조정선)을 설정하여 엔진이 서지 한계선을 넘지 않도록 제어한다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.140-141
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• 2014

차세대 전극 재료의 개발은 리튬 전지, 슈퍼 축전지, 전력 공급을 포함하는 에너지 저장 매체의 연구에 중심이 되는 요소이다. 이 가운데 금속황화물은 독특하고 우수한 특성 때문에 차세대 전극 재료로서 상당히 주목을 받고 있는 재료이다. 하지만 실제 응용 측면에 있어서 충 방전 관련된 속도와 안정성의 한계가 가장 큰 장애 요소이다. 이러한 한계를 극복하고자 나노구조화에 대한 연구가 집중적으로 진행되고 있다. 본 논문에서는 금속황화물의 에너지 저장 매체로서의 연구 내용을 기술하였다.

• Proceedings of the Korea Multimedia Society Conference
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• 2003.05b
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• pp.699-702
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• 2003

버블론 이후 인터넷 기업은 안정적인 수익창출을 위한 다양한 시도와 역량을 집중하고 있으나 대부분의 기업 뿐만 아니라 웹캐스팅 업체도 여전히 적자 상태이다. 본 연구에서는 컨텐츠 비즈니스의 구체적인 신조류를 분석하며, 기존의 웹캐스팅 비즈니스의 수익모델을 분석하여 그 한계요소를 도출하고 이들의 해결안을 광고, 컨텐츠 유료화, 컨텐츠 개발 및 확보, 전자상거래, 컨텐츠 전달방식, 전자결제방식, 매체 확장 등 인터넷 비즈니스 요소 측면에서 제시함으로써 수익성 제고를 모색해 보았다.

• Journal of Digital Convergence
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• v.12 no.7
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• pp.297-304
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• 2014

The present study was designed to investigate the effect of home based exercise program on balance recovery of stroke patients. In total, 20 participants were assigned to a control group(n=10) or exercise group(n=10) between September 2013 and December 2013. In addition to existing physiotherapy, the exercise group received home based exercise program consisting of weight transfer, training endurance, mobility, sensory retraining, lower limb exercise for 30 minutes, 2 times a week, for 8 weeks, every time for 30 minutes. Balance ability was assessed by measuring foot pressure(FP), limit of stability(LOS) and velocity sway(VS) by using Biorescue and by using the functional reaching test(FRT). To compare the improvement level of each group's balance ability, examination of independent sample T was done. Significant differences between control group and exercise group in LOS, VS of affect side and FRT were observed. This study showed that home based exercise program application was effective strategy on balance recovery in a post stroke population.

• The Journal of the Korea Contents Association
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• v.13 no.10
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• pp.9-18
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• 2013

In this paper, we analyzed the effects of game-based visual feedback training on postural balance control in young adults and older adults. We provided postural balance training by 23 young adults and 14 older adults and for four weeks in fifth minute a day and three days a week using IBalance(Cybermedic Inc., Korea). We evaluated the ability of postural balance using balance SD(Biodex, medicalscience Inc., USA) for the validation of game contents based on visual feedback training program. The results showed that postural stability and limits of stability of young adults and older adults were improved significantly before and after the training(p<0.05). Thus, the games of postural balance encouraged anterior, posterior, medial, lateral and multidirectional weight shifting regarding postural balance. Our study indicates that postural balance training of visual feedback based game could be adapted for improving postural balance. Moreover, we could develope of game contents for individuals and various ages for effective application of this game-based visual feedback training.