• Defense and Technology
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• no.10 s.152
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• pp.58-63
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• 1991

유도무기의 개발에서 관성유도에 필요한 관성합법장치 기술의 확보는 필수적이다. 관성항법장치의 핵심부품이 되는 자이로 기술 및 발전추세에 대해서는 국내 학술회의에서 최근에 발표된바 있으므로, 이글에서는 국내의 관성항법장치 연구개발에 관심이 있는 관계자가 관성항법장치 기술을 개괄적으로 이해하는데 도움이되도록 꾸며 보았다. 이에따라 관성항법장치 시스템에 대한 기본 원리, 하드웨어 설계제작 및 시험 평가 소요 기술, 그리고 관성항법장치의 유도탄 응용현황 및 발전 추세 등을 개략적으로 기술하였다. 이어 국내의 관성항법장치 보유 기술 및 추후 연구 개발이 필요한 기술에 대해 덧붙였음을 알린다

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.183-186
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• 2004

본 논문에서는 수중 초음파 통신용 QPSK 버스트 수신기를 DSP시스템을 이용하여 구현하기위한 시스템 설계에 대하여 논한다. 본 논문에서 고려하는 시스템은 25kHz의 반송주파수를 사용하고, 심벌율은 5kHz이며, 데이터 전송율은 10,000bps이다. 송신기에서 심벌정보를 전송하기 위해 펄스성형필터를 거친 신호를 디지털 믹서기를 이용하여 디지털 영역에서 반송주파수 대역으로 신호를 변조한 후 200kHz로 샘플링하는 D/A변환기를 이용하여 전송 아날로그 신호를 생성한다. 수신기에서는 수신 신호를 디지털로 처리하기 위하여 100kHz로 free running하는 A/D 변환기를 이용하여 수신 데이터를 얻는다. 수신기에서는 32심벌 길이의 프리앰블을 이용하여 프레임 동기를 찾음과 동시에 개략적인 심벌시간 동기와 위상편이를 추정한다. 추정한 위상편이값은 2차 PLL (phase-looked loop)의 초기값으로 사용하여 위상 추적을 수행하는 전송 시스템이다. 또한, 된 논문에서는 실해역 전송 시험 테이터를 통하여 조류의 변화에 의해 발생하는 Doppler 편이를 보상하기 위하여 PLL이 필수적으로 필요함을 보인다.

• Journal of Ocean Engineering and Technology
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• v.16 no.6
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• pp.76-81
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• 2002

The purpose of this study is to set up the optimum economical formation of the purse seiner fishing system. For this task, the characteristics of existing purse-seiner fishing system were reviewed, and the possible formations of the fleet in tile purse-seiner fishing system were examined through the reallocation of function for each individual vessel. In addition, economic evaluations of the possible formations of the fleet are carried out. Consequently, it was found that 2-vessel formations have the most economic efficiency. Then, a conceptual system design for the main vessel in the 2-vessel formations was performed. As a result, this paper can be used as a helpful guideline to develop the most profitable and economical fishing system in the fleet type fishery.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.4
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• pp.384-392
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• 2008

Design sketch of electrical power system, mass, and cost of a new satellite is an inevitable step preceding the full-scale development of the satellite. In this paper, major features of recently developed conceptual design tools of satellites are investigated. And, based on the surveying results, we summarize the conceptual design procedure of satellites. The required electrical power to support the operation of the payload mission determines the size of solar panel and battery. The mass of the integrated system and subsystems is then estimated based on the database of the previously developed satellites. Cost can also be roughly estimated using the database without consideration of complex calculations.

• The Transactions of the Korea Information Processing Society
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• v.3 no.4
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• pp.846-854
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• 1996

In this paper, we propose a solution to the software maintenance problem that is a primary factor of software crisis. We surveyed and analyzed the current software maintenance problems through questionnaires and interviews. As a result, we defined the software maintenance management life cycle and established a fundamental strategies to solve the software maintenance problems efficiently. We also designed a software maintenance management support systems to construct an automated software maintenance management tool. Furthermore, tp improve the formalization and reliability of the software maintenance management procedure, we defined acost predictive model using a fixed-single parameter based on comprehensive program size for the source code and delivered effort(person/month). We elaborated the model by considering an experience level of maintainer, a skill- level defined by the manager, and a reliability level required by the model of maintenance management.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4B
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• pp.399-404
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• 2006

Kweon et al. (2004) proposed the calculation method of Expected Overtopping Probability (EOP) that considers the occurrence frequency distribution of real sea tide. The method was applied for the comparison of the EOP of Mukho and Busan sea. They showed that the tide occurrence frequency had a great effect on the EOP and the value becomes smaller as the standard deviation of the frequency comes bigger. The present study following Kweon et al.'s method estimates the EOP characteristic of the crest elevation located on East, South, and West sea. The study shows that the EOP becomes smaller following East, South, West sea in order.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.701-704
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• 2005

In this paper, we looked into the feature of a transmission system of the terrestrial digital broadcasting system and considered a ATSC 8-VSB transmission standard. Also, we analyzed the performance with the influence of an interchannel interference by the ATSC standard. As a result, the case not to consider Rician fading, The influence of the interfere did not exist if Frequency interval fell off over the 20MHz. The case to consider Rician fading, the system had the degradation of the performance.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2006.11a
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• pp.154-160
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• 2006

There wasn't very successful practice cases for the quantity take-off based on the CAD system since the CAD system is used in the construction industry more than 20 years in Korea. It was also not easy to use 3D CAD system in design management and cost management in the construction industry although 3D CAD system is very successful in the manufacturing industry for those areas recently. It is important to construct 3D libraries and to supply those libraries for the designers in time. Architectural work is a kind of creative work. So, Architects like to create their own model. Unlike the manufacturing industry, 3D CAD system can not be survived in the construction industry without new 3D objects supply in the right time. Moreover, the estimation system for 3D must support the schematic design phase, detailed design phase and construction design phase. The product called "Constructor" of Graphisoft consist of modeller, estimator and scheduler based on 3D model. We applied the system to a real project and compared the estimation result and we made a very successful case study.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.3D
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• pp.373-379
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• 2009

Cost estimation in the early phase enables government to plan public budgeting more efficiently by providing information about construction cost. However, cost estimation in the early phase is difficult to predict because only a little information can be utilized. The cost estimation method now being used by the government is calculated by length of the road multiplied by unit cost per length and shows high error rate because it cannot reflect the unique characteristics of each project. As the project is being proceeded, level of available information also changed. So, reflecting available information of a project is important. This paper divided early phase into two parts : planning phase and early design phase, and developed cost estimation model considering level of available information of each phase. Total 143 cases are utilized to find influencing variables and develop cost estimation model and model validation is done by adopting required accuracy level. This cost estimation model reflecting level of available information can be applied to public budgeting, feasibility test, and comparison between routes.

• 전기의세계
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• v.26 no.5
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• pp.28-30
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• 1977

생산산업의 현대화저오ㄷ를 가름할 때 흔히 그 해당공정이 얼만큼의 비율로 자동제어장치가 되어 있느냐 하는것을 척도로 할 만큼 제어공학(Control Engineering)이 일반생산산업에 미치는 영향은 크다고 믿어진다. 이처럼 자동제어화의 인기가 높은것은 단순히 그렇게 함으로서 편리한 것 뿐만아니라, 그 기업의 수익을 증가시키기 때문일 것이다. 기업가의 입장에서 볼때, 자동제어의 결과로 (i)생산속도를 증가시키고, (ii) 규격치로부터의 오차를 줄임으로서 제품의 질을 향상시키고 (iii)생산원료를 절약하여 원가절감을 할 수 있는등의 이점이 있다. 이외에도 일상생활 환경에서 접하는 엘리베이터의 승강제어부터 우주선의 비행제어에 이르기까지 제어의 개념은 현대기술문명의 본질인 것이다. 본란을 통하여, 제어공학자들이 현재 사용하고 있는 설계방법과 앞으로의 발전경향에 대하여 간단히 소개하고, 아울러 학계 및 제어공학자들의 많은 관심을 모으고 있는 누연시스템(Tine-delay system)의 제어문제에 대하여 개략적으로 설명하기로 한다.