• 한국추진공학회지
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• 제5권1호
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• pp.60-68
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• 2001

본 논문은 무궁화위성 3호의 잔여연료량 추정을 위해 사용된 열질량법에 대한 기본적인 이론과 오차분석에 대한 내용을 정리하였다. 연구과정에서 잔여연료량 추정에 대하여 무궁화위성 3호의 CDR(Critical Design Review)의 데이터를 분석하였고 이를 바탕으로 하여 잔여연료량을 추정하였다. 그리고 해석적 방법으로 오차분석과정을 검증하여 보았고 이를 Monte Carlo 방법을 사용한 결과와 비교 검토하였다.

• Nuclear Engineering and Technology
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• 제53권6호
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• pp.1878-1886
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• 2021

For industrial package (IP)-type transport containers for radioactive materials, a free drop test should be conducted under regulatory conditions. Owing to various uncertainties observed during the drop test, errors in drop angles inevitably occur. In IP-type metal transport containers in which the container directly impacts onto a rigid target without any shock absorbing materials, the error in the drop angle due to a slight misalignment makes a significant difference from the ideal drop. In particular, in a vertical drop, the error in the drop angle causes a strong secondary impact. In this paper, a numerical method is proposed to estimate the error in the drop angle occurring during the test. To determine this error, an optimization method accompanying a computational drop analysis is proposed, and a surrogate model is introduced to ensure calculation efficiency. Effectiveness of the proposed method is validated by performing the verification and comparison between the test and the analysis applied with the drop angle error.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.1155-1160
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• 2009

The trend in construction industry, now, lies in improving efficiency and competitive power in construction management and on-the-spot instruction by combining with new IT technology. Above all, it is safe to say that the application of RFID technology can play a pivotal role at this point, but it is not that easy to apply RFID due to the physical, chemical and environmental peculiarities of construction materials. Thus, a study on the standardization of the usable frequency, specifications, protocol, and package administration is required. This study, as part of the study on the standardization, figured out the restrictions by attaching the existing RFID Tag to the construction materials, turned out the prototype of RFID Tag to perform a field test. In result the effective recognition range varies according to the physical and environmental peculiarities of construction materials; and the management efficiency varies as the attaching method and/or applying method. To analyze the management method (media, process etc.) systematically for the existing construction materials; to prepare more various restrictions and its solutions for practical construction spots will be the key for successful RFID implementation.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.147-149
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• 2015

A nuclear power plant construction project normally involves a large construction work of which the total project cost is over 5 trillion Won, Such a large-scale construction project has the risks of schedule delay and quality degradation due to increase in project cost, because designs are changed due to design errors. The reasons for design changes during installation are 1) insufficient engineering capability of the owner, 2) information discontinuance due to the multiple package method, and 3) inefficient constructability review processes. Accordingly, this study proposes, through problem analysis, a method of developing a constructability review system that utilizes constructability review processes and a data-based technology (3D modeling) that are optimized for nuclear power plant construction projects. It also presents a method of establishing a system for reviewing constructability in which constructability review processes and a Database (3D model, Schedule, Design change Items) are linked each other.

• 한국한의학연구원논문집
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• 제18권2호
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• pp.55-64
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• 2012

Objectives: This study was performed to review the use of statistical analysis methods for the Traditional Korean Medicine studies listed on the Korea Citation Index from 1999 to 2008. Methods: A total of 4217 studies published on four journals of Traditional Korean Medicine were screened and 2682 articles using statistical methods were selected for the review. The selected studies were analysed according to their published year, statistical method and statistical package for use. Results: Statistical methods were used steadily in 64.6% of the articles after 2001, the most used statistical methods(57%) were mean difference comparison between 2 groups. The number of statistical methods mostly used in one article was identified as one in 1931 articles (72.0%). Duncan (36.8%) and Tukey (26.5%) were used for the ANOVA post hoc analysis. SPSS was most frequently used 68% out of Statistical package programs.(the number of mean difference comparison among more than 3 groups was continuously increasing and that makes post hoc being used. skills of statistical methods need to be diversified.) Conclusion: The interest on the proper use of statistical analysis in the research is increasing. This study will contribute to the Evidence-based Teaching on research methodology in Traditional Korean Medicine.

• 대한인간공학회지
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• 제33권2호
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• pp.87-96
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• 2014

Objective: The present study is intended to objectively classify upper- & lower-body sitting strategies and identify the effects of gender and OPL type on the sitting strategies. Background: A sitting strategy which statistically represents comfortable driving posture can be used as a reference posture of a humanoid in virtual design and evaluation of a driver's seat. Although previous research has classified sitting strategies for driving postures in various occupant package layout (OPL) types, the existing classification methods are not objective and the factors affecting sitting strategies have not been identified. Method: Forty drivers' preferred driving postures in three different OPL types (coupe, sedan, and SUV) were measured by a motion capture system. Next, the measured driving postures were classified by K-means cluster method. Results: Sitting strategies of upper-body were classified as erect (33%), slouched (41%), and reclined (26%) postures, and those of lower-body were classified as knee bent (42%), knee extended (32%), and upper-leg lifted (26%) postures. Significant differences at ${\alpha}$ = 0.05 in the upper-body sitting strategy by gender and lower-body sitting strategy by OPL type were found. Application: Both the classified sitting strategies and the identified factors would be of use in ergonomic seat design and evaluation.

• Composites Research
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• 제25권6호
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• pp.211-216
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• 2012

광섬유센서는 구조물에 매립 또는 부착시 전단응력에 의해 편광이 발생하여 피크가 2개로 갈라질 수 있기 때문에 센서는 보호되고 양 끝단을 고정하는 방법으로 패키징을 하여야 하나, 광섬유의 클래딩 부분을 부착하는 방식으로 고정하면, 변형발생시 광케이블을 구성하는 코어와 클래딩 사이에서 미끄러짐 현상이 발생하기 때문에 이를 방지하기위해 센서의 양 끝단에 고정구를 사용하고 광섬유를 부분탈피하여 부착하여 접점을 만들어 줌으로써 외력에 의해 발생하는 변형을 정확하게 측정이 가능하도록 하였다. 그리고 기존 광섬유격자센서가 자체적으로 압축변형의 측정이 곤란한 점을 개선하기위해 미리 긴장(Pre-Strain)상태를 유지하기 위하여 두 개의 접점사이를 볼트와 너트로 조절하여 프리스트레인 가변이 가능하도록 하여 인장/압축변형 측정을 가능하게 한 광섬유격자센서 패키지를 제작하였다. 이러한 광섬유격자센서패키지를 실제구조물에 적용하여 측정하였으며, 이를 통하여 안전을 감시하는 모니터링시스템에 적용할 수 있도록 하였다.

• 한국자동차공학회논문집
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• 제21권5호
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• pp.8-14
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• 2013

In this study, we propose the method of optimally selecting material of front pillar (A-pillar) and package tray for minimizing weight while satisfying vehicle requirements on static stiffness and dynamic stiffness. First, we formulate a material selection optimization problem. Next, we establish the CAE procedure of evaluating static stiffness and dynamic stiffness. Then, to enhance the efficiency of design work, we integrate and automate the established CAE procedure using a commercial process integration and design optimization (PIDO) tool, PIAnO. For effective optimization, we adopt the approach of metamodel based approximate optimization. As a sampling method, an orthogonal array (OA) is used for selecting sampling points. The response values are evaluated at the sampling points and then these response values are used to generate a metamodel of each response using the radial basis function regression (RBFr). Using the RBFr models, optimization is carried out an evolutionary algorithm that can handle discrete design variables. Material optimization result reveals that the weight is reduced by 49.8% while satisfying all the design constraints.

• 한국컴퓨터정보학회논문지
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• 제17권6호
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• pp.67-73
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• 2012

본 논문에서는 컨퍼런스 서버의 과부하를 방지하기위한 새로운 부하 제어 방식을 사용한 분산형 컨퍼런스 구조를 제안하였다. 본 논문에서 제안한 새로운 이벤트 패키지는 컨퍼런스 부하 제어를 가능하게하고 새로운 컨퍼런스 정보 데이터 포맷은 컨퍼런스 서버들과 컨퍼런스 참가자들 사이의 SIP 메시지 교환 절차 및 부하 분산을 처리하는 데 필요한 요소들이 추가되었다. 또 전체 컨퍼런스 참가자들에게 주기적으로 전송해야 할 컨퍼런스 정보 데이터의 처리도 모든 서버들이 분담하도록 하여 부하를 더욱줄이도록 하였다. 제안한 부하제어 이벤트 패키지는 각 컨퍼런스 서버들이전체 컨퍼런스서버들의현재부하 상태를 실시간으로파악할수 있도록 하며특정서버의부하가커지면 해당 서버는 전체 컨퍼런스 서버 중 가장 부하가 적은 서버를 선택하여 SIP 클라이언트 요청을 분산시키거나 새로운 컨퍼런스 서버를 생성하여 부하를 분산하도록 한다. 제안된 시스템의 성능은 실험을 통하여 분석하였고 평균 지연시간에서 21.6%, 평균 SIP 메시지 처리 시간에서 29.2% 향상됨을 보여주고 있다.

• 마이크로전자및패키징학회지
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• 제26권4호
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• pp.89-94
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• 2019

전력저장용 전기에너지 저장장치의 일종인 NaS 전지 단위 셀을 개발함에 있어서 알파-알루미나 절연세라믹 캡과 베타-알루미나 전해질 튜브 간의 세라믹-세라믹 상호 접합을 위하여 글라스 기반의 실링소재가 필요하다. 본고에서는 이 세라믹-세라믹 접합용 글라스 실링 페이스트를 제조함에 있어서, 열간 칭법에 의한 글라스 프릿 제조와 상분석, 분말입도 분석 및 글라스 조성에 따른 열팽창계수 변화 및 표면거칠기를 분석하였다. 또한 글라스 실란트의 접합력 평가를 위해 종래 솔더 볼 조인트의 접합력 평가용 분석장비인 Dage bond tester를 이용하여 세라믹-세라믹 컴포넌트의 작은 접합면에 대한 접합력 측정 방법을 제안하였다.