• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.539-540
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• 2006

소형 열병합 (CHP, Combined Heat & Power)은 발전 용량이 1MW 이하인 발전 시스템을 지칭하는 용어로, 전기와 더불어 원동기에서 발생한 폐열을 회수하여 사용한 수 있는 발전 시스템을 말한다. 대표적인 원동기로서는 가스 엔진, 터빈, 마이크로 터빈, 연료 전지 등이 있다. 소형 열병합 시스템은 폐열 회수의 특징으로 기존 시스템에 비해 50% 이상의 에너지 이용 효율이 높으며, 기존의 대형 발전 시스템에서 필연적으로 존재하는 송전 및 배전 손실이 존재하지 않는 수요지 발전의 특징도 갖고 있어서 연료 절약형 에너지 생산 시스템으로서의 높은 가치를 가지고 있다. 또 다른 장점으로 열병합 발전 시스템은 여름철의 최대 전력 부하를 제거하는 역할을 할 수 있음으로 국가 전력 수요 공급의 안정화에 기여하는 바가 크다. 본 논문에서는 최근에 개발된 325kW급 열병합 가스엔진 발전 시스템의 주제어를 담당하는 통합 제어 장치의 개발과 소형 열병합 시스템의 시험 결과에 대해서 소개한다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.23 no.2
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• pp.183-189
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• 2010

This paper deals with the comparison of analysis methodologies by applying both Euler angle and quaternion to observe the kinematical behavior of the universal joint system used as an automotive drive-shaft. At first, conventional approaches are applied to predict a kinematical behavior by introducing only Euler angles into the universal joint system, but turns out to be lack in consistency and reliability of the analysis. Then to overcome this deficiency in numerical analysis a different methodology is proposed by using quaternion in this system. Its corresponding advantage is discussed in terms of kinetic energy, rotational velocity and rotational displacement. The application of quaternions in the numerical experiment is shown to be a more useful and valid way of establishing the ideal analytical model of the universal joint system.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2003.12a
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• pp.406-411
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• 2003

최근, 디지털 기술과 네트워크의 발달로 다양한 무선통신 단말기, 반도체, 디지털 방송, 전자상거래 등 다양한 분야가 융합되어 사람과 디바이스간에 실시간으로 정보를 주고받는 환경 즉, 유비쿼터스 컴퓨팅 환경에 많은 관심이 주목되고 있다. 이러한 유비쿼터스 컴퓨팅 환경에서의 통신은 통신개체간에 실시간 개체인증은 물론 전송되는 정보의무결성, 기밀성 등 보안 서비스가 요구된다. 현재의 개체 인증은 사용자가 기억하는 패스워드 또는, 스마트 카드와 같은 보안 모듈을 사용하여 사용자와 개체간에 인증이 이루어지고 있는 실정이다. 이러한 방식은 사용자가 기억해야 할 패스워드가 증가한다거나, 보안 모듈의 손상 및 분실로 인해 자신의 프라이버시(privacy)가 노출될 수 있는 단점이 있다. 이에 본 논문에서는 사용자 고유의 생체 정보와 기억할 수 있는 패스워드를 비밀정보로 사용하여 양방향 개체 인증 키 분배 프로토콜을 제안한다.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2003.12a
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• pp.393-398
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• 2003

본 논문에서는 사용자 인증에 사용되는 패스워드 검증자의 안전성을 더욱 보강한 새로운 패스워드 검증자 기반 키 분배 프로토콜을 제안한다 기존 패스워드 기반 키 분배프로토콜 방식은 네트워크 상에서 패스워드의 안전한 전송이 어려웠고, 패스워드 파일의 안전한 보호가 어렵다는 문제가 있었다. 이에 패스워드 파일을 그대로 서버에 저장하지 않고 패스워드를 사용하여 생성한 검증자(verifier)를 저장하게 함으로써 패스워드파일을 보다 안전하게 보호할 수 있게 되었으며, 서버가 사용자의 패스워드를 알지 못하더라도 검증자를 사용한 증명방식을 통해 사용자를 인증할 수 있게 되었다. 본 논문에서는 사용자와 서버의 비밀정보로 만든 새로운 형태의 검증자를 사용하고, 사용자는 다른 저장정보 없이 기억하고 있는 ID와 패스워드만을 사용하여 키 분배를 수행하는 패스워드 검증자 기반 키 분배 프로토콜을 제안한다. 제안하는 프로토콜의 안전성 분석을 위해 active impersonation과 forward secrecy, man-in-the-middle attack, off-line dictionary attack 등의 공격 모델을 적용하였다.

• Journal of the Mineralogical Society of Korea
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• v.26 no.3
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• pp.161-174
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• 2013

The geology of the weondong deposit area consists mainly of Cambro-Ordovician and Carboniferous-Triassic formations, and intruded quartz porphyry and dyke. The skarn mineralized zone in the weondong deposit is the most prospective region for the useful W-mineral deposits. To determine the skarn-mineralization age, U-Pb SHRIMP and K-Ar age dating methods were employed. The U-Pb zircon ages of quartz porphyry intrusion (WD-A) and feldspar porphyry dyke (WD-B) are 79.37 Ma and 50.64 Ma. The K-Ar ages of coarse-grained crystalline phlogopite (WD-1), massive phlogopite (WDR-1), phlogopite coexisted with skarn minerals (WD-M), and vein type illite (WD-2) were determined as $49.1{\pm}1.1$ Ma, $49.2{\pm}1.2$ Ma, $49.9{\pm}3.6$ Ma, and $48.3{\pm}1.1$ Ma, respectively. And the ages of the high uranium zircon of hydrothermally altered quartz porphyry (WD-C) range from 59.7 to 38.7 Ma, which dependson zircon's textures affected by hydrothermal fluids. It is regarded as the effect of some hydrothermal events, which may precipitate and overgrow the high-U zircons, and happen the zircon's metamictization and dissolution-reprecipitation reactions. Based on the K-Ar age datings for the skarn minerals and field evidences, we suggest that the timing of W-skarn mineralization in weondong deposit may be about 50 Ma. However, for the accurate timing of skarn mineralization in this area, the additional researches about the sequence of superposition at the skarn minerals and geological relationship between skarn deposits and dyke should be needed in the future.

• The Journal of Korean society of community based occupational therapy
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• v.4 no.1
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• pp.23-31
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• 2014

Objective : The objectives of this study were to compare the variables from Fitmeter accelerometer with them from CMS-70P(Zebris Medizintechnik Gmbh, Germany) and to suggest the availability the accelerometer in the field of occupational therapy. Methods : Twenty participants performed calling, drinking water, washing face and spooning and we measured Sum of Single Vector Magnitude(SSVM) and range of motion(ROM) on the wrist and elbow joints. Results :With respect to the wrist and elbow joints, SSVM and ROM differed significantly according to the task(calling, drinking water, washing face and spooning)(p<.001; p<.001; p<.001; p<.001). As for the wrist joint, SSVM and ROM did not show the significant correlation(p>.05) but as for the elbow joint, SSVM and ROM did show the significant correlation according to the task(p<.01; p<.001; p<.01; p<.05). With regard to the SVM-difference of wrist and elbow joints, calling and washing showed the significant difference (p<.001; p<.05) but drinking and spooning did not show the significant difference(p>.05; p>.05). Conclusion : We suggest that Fitmeter accelerometer would be use to record the kinematic variables during performance of ADL and it can compensate the function of CMS-70P as for the elbow joint than the wrist joint.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.6
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• pp.626-634
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• 2005

The objectives of this study was to assess pollution level and contamination status on tailings and soil in the vicinity of four disused metal mines in Kangwon province. As the result of total metal concentrations analysis, the pollution degree of tailings and soil decreased in the order of Wondong > Second Yeonhwa > Sinyemi ${\fallingdotseq}$ Sangdong mines. Total metal concentrations of mine tailings in this study were $1.2{\sim}78.2$ and $1.1{\sim}80.6$ times higher than those in the background soil and the tolerable levels suggested by Kloke, respectively. From these results, we found that tailings served as contamination source of nearby soil. According to sequential extraction of metals, large proportion of heavy metals in all mine tailings existed in the form of a residual fraction, and heavy metals in non-residual form was mainly associated with Fe-Mn oxide fraction and sulfidic-organic fraction. Fe-Mn oxide fraction and sulfidic-organic fraction of heavy metals may be released into and contaminated the nearby environment under the oxidation or reduction condition in long-term. In particular, the proportions of the exchangeable and carbonate fraction of Cd in mine tailings from Second Yeonhwa mine were relatively high. This suggests that Cd may be easily released into and contaminated the nearby environment in the near time. Concentrations of heavy metals in mine tailings and the nearby soil exceeded the standard (agricultural area) of Soil Environment Conservation Law. So it was thought that remediation for mine tailings and the nearby soil is needed. The pollution indices of the samples in this study were for higher than 1.0 and the pollution degree was very serious. Priority remediation site for these mines was Wondong. As Results of danger indices, it was showed that exchangeable form in Wondong and Fe-Mn oxide form in the rest mines should be removed preferentially.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.9
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• pp.1070-1074
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• 2014

According to IEEE 1662(2009), IPS is a power system where all prime movers produce electrical power that is shared among propulsion, mission, and ship service loads. Discriminating attributes of integrated power systems are flexibility of movers' arrangements, mechanical decoupling between prime movers and propulsors, an increased level of energy conversion and transmission redundancy, and flexibility of redistributing available electrical power for future electronic weapons. IPS could have various steps of power that can be produced at optimal load of movers. In this study, an evaluation method for optimal arrangement of movers was investigated when an IPS warship is projected. The two factors are utilized for the quantitative analysis which are the weight of system as the fighting power and the fuel consumption per year as the economic feasibility. And also the ways for arrangement of system were studied according to existence of small diesel generator. The evaluation method that decides the optimization level is based on the DEA(Data Envelopment Analysis)

• Review of KIISC
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• v.11 no.1
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• pp.1-8
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• 2001

초고속국가망을 이용하는 기관은 국가 및 지방자치단체 등 공공기관이 대부분을로 정보시스템에 보안사고 발생시 정보 유출, 파괴, 서비스 마비 등이 발생하여 해당기관의 생존뿐만 아니라 나아가 국가의 안위까지도 위협될 수 있음에 따라 초고속망 안전·보안이 주요 이슈로 등장하고 있다. 이에 따라 본 논문은 초고속국가망 이용기관 측면에서, 체계적인 보안관리를 가능케 하는 정보기술 보안관리 일반모델을 소개하고 통신사업자 측면에서, 비상시에도 안정적으로 초고속국가망 서비스를 제공하는 방안에 대해서도 소개한다.

• Proceedings of the Korean Magnestics Society Conference
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• 2006.06a
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• pp.126-126
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• 2006