• Journal of the Korea Society for Simulation
• /
• v.26 no.4
• /
• pp.11-21
• /
• 2017

This paper discusses the design parameter sensitivity analysis and multi-objective function optimization for improving the impact performance of an auto-sensing breaker based on the analytical model of the same, which secured reliability in a previous research. The study aims to improve both impact power and stability by complementing the existing research that only improved the impact power. The study sequence is as follows: first, the analysis scenarios for the accurate sensitivity analysis and optimization are set up. Second, the sensitivity of the design parameter of the auto-sensing breaker is analyzed, and the variables with high sensitivity are extracted. Third, the extracted variables are used to optimize the multi-objective functions, and the optimized performance is compared with the initial performance to see how the impact performance on the existing auto-sensing breaker has improved. This study is based on domestic technology, and will allow the development of products with a better blowing performance than their existing overseas counterparts.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.43 no.7
• /
• pp.601-608
• /
• 2015

The static aeroelastic analysis and optimization of flexible wings are conducted for steady state conditions while both aerodynamic and structural parameters can be used as optimization variables. The system of multidisciplinary design optimization as a robust methodology to couple commercial codes for a static aeroelastic optimization purpose to yield a convenient adaptation to engineering applications is developed. Aspect ratio, taper ratio, sweepback angle are chosen as optimization variables and the skin thickness of the wing. The real-coded adaptive range multi-objective genetic algorithm code, which represents the global multi-objective optimization algorithm, was used to control the optimization process. The support vector regression(SVR) is applied for optimization, in order to reduce the time of computation. For this multi-objective design optimization problem, numerical results show that several useful Pareto optimal designs exist for the flexible wing.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.13 no.3
• /
• pp.91-101
• /
• 2010

As global warming has caused the number of abnormal changes in climate to increase throughout the world, much damage has occurred recently in Korean Peninsula which results from unexpected heavy rains, landslides, and floods from typhoons. To prevent and cope with these annually repeated natural hazards, the overall improvements are needed, including systematic management of the existing natural hazard information and improvement of hazard information. In this study, multi-purpose hazard information map based on digital image was constructed as an effective way to enhance hazard management considering regional characteristics and hazard response capabilities in the field. Multi-purpose hazard information map with a new concept by fusion of geospatial information and hazard attribute information is able to support quick decision for hazard management making and development of hazard information system.

• Journal of Korea Water Resources Association
• /
• v.41 no.12
• /
• pp.1211-1218
• /
• 2008

This study is for design of the detention system distributed in a watershed by the Multi-Objective Genetic Algorithms(MOGAs). A new model is developed to determine optimal size and location of detention. The developed model has two primary interfaced components such as a rainfall runoff model to simulate water surface elevation(or flowrate) and MOGAs to get the optimal solution. The objective functions used in this model depend on the peak flow and storage of detention. With various constraints such as structural limitations, capacities of storage and operational targets. The developed model is applied at Gwanyang basin within Anyang watershed. The simulation results show the maximum outlet reduction is occurred at detention facilities located in upper reach of watershed in the peak discharge rates. It is also reviewed the simultaneous construction of an off-line detention and an on-line detention. The methodologies obtained from this study will be used to control the flood discharges and to reduce flood damage in urbanized watershed.

• Journal of the Korea Society for Simulation
• /
• v.28 no.2
• /
• pp.35-48
• /
• 2019

Domestic hydraulic drifters till now have been developed by benchmarking products from overseas leading companies. However, they do not have excellent impact performance as they are not suitable for characteristics (large flow rate and low pressure) of Korean hydraulic drill power pack, and therefore, research on the optimum design has not made much headway. This study performs multi-objective function optimization for hydraulic drifters whose capacity has been redesigned to deal with the large flow rate, and also with the help of this function, it aims to improve impact power and reduce supply and surge pressure. A summary of the research study is as follows: First, we set goals for improving impact power, supply pressure, and surge pressure, and then perform multi-objective function optimization on them. After that, we secure the reliability of the optimized analytical model by comparing the test results of the prototype built by the optimized design with the analysis results of the analytical model. This study used SimulationX, that is the hydraulic system analysis software, and EasyDesign, which is a multi-objective function optimization program. Through this research, we have achieved the results that satisfy the goal of developing high power drifters suitable for Korean type hydraulic drills.

• Journal of the korean Society of Automotive Engineers
• /
• v.7 no.1
• /
• pp.63-67
• /
• 1985

KIA는 호평의 Bongo-9을 기본 model로 하여 도시형 다목적 leisure car인 Bongo-town을 개 발하게 되었다. TX엔진은 Bongo-town 탑재용으로 기존 1.3l TC 엔진을 volume-up 하여 전 회전 영역에서 괄목할 성능향상을 보였으며 특히 탑재차량의 특성을 고려하여 저속영역 torque를 강조하였고 부품호환성 및 생산 설비의 공용화에도 주력했다. 주요 개발내용은, 1) Cooling passage 개선 및 full siamese화 2) Piston과 connecting rod의 신설계 3) Piston 조합의 semi floating화 4) Cam shaft profile 선정 및 valve timing 변경 5) Distributor 최적진각특성 결정 6) Carburetor 개발 7) Torque limited fan and fan drive 채용 등이다. 상기내용중 중요한 몇가지를 기술하고자 한다.

• Defense and Technology
• /
• no.8 s.294
• /
• pp.72-81
• /
• 2003

해외 파병시마다 매번 거론되어 온 전개형의무시설은 무기체계측면에서 신규첨단 전력의 연구개발을 위한 장기적인 투자가 긴요하다고 판단한다. 대내저기으로 한반도내 작전지역 뿐만 아니라 재해재난시 신속 전개를 위한 다목적 의료시설이 요구되는 곳에 설치 활용할 수 있는 전개의무시설 개발 여건개선이 이뤄져야 할 것이며, 대외적으로는 세계평화에 기여하고, 한국군 위용을 과시할 수 있는 전개형의무시설을 확보하여 의무전력을 확대하여 나가야 겠다.

• Defense and Technology
• /
• no.9 s.271
• /
• pp.14-25
• /
• 2001

현재 협상중인 공군의 F-X 사업은 70% 이상을, 육군의 AH-X 사업은 50% 이상을 달성하기 위하여 협상력 발휘에 최선을 다하고 있다. 획득대상은 핵심 기술획득, 부품제작 수출 등으로 우선순위는 국방부에서 대상사업에 따라 결정토록 하고 있다. 획득중점 목표는 향후 개발 무기체계 소요기술을 확보하는데 두고 있으며, F-X 사업의 경우는 한국형 전투기 개발 기술을, AH-X 사업에서는 한국형 다목적 헬기 개발기술을 획득하는데 중점을 두고 있다.

• Defense and Technology
• /
• no.5 s.219
• /
• pp.52-63
• /
• 1997

JSF사업은 다수 군이 사용할 수 있는 공통항공기를 생산하여 항공기 전 운영기간의 운영경비를 줄이는데 중점을 두고 있기때문에 소요군 각각이 전투기를 개발하는 것에 비해 개발비를 50% 정도까지 줄일 수 있을 것으로 추정하고 있다. JSF 항공기는 공대지 임무에 중점을 두게 될 다목적 전투기로, JSF 사업실은 경합중이던 3개 업체의 사업 제안서를 제출받아 보잉, 록히드 마틴 2개업체를 선정한 바 있으며 현재는 개념 시범 단계에 진입해 있다

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.47 no.6
• /
• pp.460-467
• /
• 2019

This paper proposes a multi-objective optimization (MOO) framework for conceptual design of a surface-to-surface missile system. It can generate the set of Pareto optimal system design, which can be used for system trade-off study in a very early stage of the research and development process. The proposed framework consists of four functional modules (an environmental setting module, a variable setting module, a multidisciplinary analysis module and an optimization module) to make the model easy to change, and the concept design process using the framework was able to achieve the purpose of reviewing various designs in the early stage of development. A case study demonstrating the effectiveness of the framework has presented applicability to the system design, and the proposed framework has contributed to presenting a design environment that can ensure reliability and reduce computational time in the conceptual design stage.