• Earthquakes and Structures
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• 제25권6호
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• pp.399-415
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• 2023

In this study, we investigate the use of a negative stiffness tuned inerter damper system to improve the performance of a base-isolated structure. The negative stiffness tuned inerter damper system consists of a tuned inerter damper connected in parallel with a negative stiffness element. To find the optimal parameters for the base-isolated structure with negative stiffness tuned inerter damper system, we develop an optimization method based on performance criteria. The objective of the optimization is to minimize the superstructure acceleration response ratio, while ensuring that the base displacement response ratio remains below a specified target value. We evaluate the proposed method by conducting numerical analyses on an eight-story building. The structure is modeled using both a simplified 3-degree-of-freedom system and a more detailed story-by-story shear-beam model. Lastly, a comparative analysis using time history analysis is performed to compare the performance of the base-isolated structure with negative stiffness tuned inerter damper system with that of the base-isolated structure and base-isolated structure with tuned inerter damper systems. The results obtained from the comparative analysis show that the negative stiffness tuned inerter damper system outperforms the tuned inerter damper system in reducing the dynamic seismic response of the base-isolated structure. Overall, this study demonstrates that the negative stiffness tuned inerter damper system can effectively enhance the performance of base-isolated structures, providing improved seismic response reduction compared to other systems.

• Strategy21
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• 통권39호
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• pp.140-162
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• 2016

The construction of Jeju Naval Base was finally completed and donated to the Republic of Korea Navy on February 26th this year. There is no doubt that the new base will contribute to the substantial augmentation of Korea's naval power and maritime security. However, we should note that the new naval base took a long and hard twenty-three years to be completed. In the 21st century, Korea should adopt a new strategy that can fulfill the security requirements of Korea for the new age of international relations. The 21st century is characterized by globalization, and in the world of globalization, a national boarder has become meaningless. In the late 20th century, after the Cold War, trade between countries have greatly increased and so did the importance of the seas. Having transformed from an agricultural country into a commercial country, Korea went from a continental state to a maritime state. Korea has become the 9th largest trading state, and obviously, the importance of the sea has become significant. Korea's national strategic focus needs to be on the sea for national survival. Thus, since the 1990s, the Korean Navy has planned to build the Jeju Naval Base. Jeju, due to its geopolitical characteristics, is extremely important to the 21st century Korea's economy and national security. Jeju is the starting point of the sea route that reaches out to the world, and at the same time, the ending point of the sea route that heads towards Korea. Jeju is located in the center of Northeast Asia and thus, Jeju Naval Base is extremely important for the area's security and order. Jeju Naval Base will be very useful not only for the maritime security of Korea, but also for keeping peace and order in Northeast Asia. Jeju Naval Base was the minimal effort against the six sea route security threats towards Korea. The six sea route threats are: 1) Threat from North Korea; 2) China's Threat towards Korea's sovereignty; 3) China's treat towards Korea's fishery; 4) Threat from Japan; 5) Threat towards Korea's sea routes; 6) Threat from recent phenomena of isolationism of the United States. Jeju Naval Base is built for both warships and civilian ships--such as cruise ships--to use. Just like the United States' Pearl Harbor, Jeju Naval Base will become not only the largest military base, but a beautiful tourist site.

• KSTLE International Journal
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• 제2권2호
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• pp.120-126
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• 2001

Performance requirements for automatic transmission fluids have been changed reflecting the design changes of automatic transmissions. The major purpose of these design changes is concentrated upon improvements of both fuel economy and drivability. In order to formulate such high performance ATFs as satisfy those requirements, it is necessary to use high quality base oils like VHVI base oils and PAOs. In this study, the effect of base oils characteristics on ATF performance is investigated, mainly regarding differences in frictional characteristics with deterioration. Frictional characteristics are determined using the SAE No. 2 machine and ATFs are deteriorated under various controlled conditions. Moreover low-temperature fluidity, oxidation stability, and seal compatibility are also compared for four different ATFs. From the investigation, it was found that the use of Group III and IV base oils in ATFs gives several benefits with respect to low temperature viscosity, oxidation stability and SAE No.2 friction characteristics.

• International Journal of Air-Conditioning and Refrigeration
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• 제16권3호
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• pp.83-88
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• 2008

A geometrically asymmetric trapezoidal fin is analyzed using the one-dimensional analytic method. Heat loss and thermal resistance are represented as a function of the fin base thickness, base height, fm shape factor, inside fluid convection characteristic number, convection characteristic numbers ratio, fm length and ambient convection characteristic number. The relationship between the fin base height and the shape factor for equal amounts of heat loss is presented. One of the results shows that the variations of the fm base thickness and the inside fluid convection characteristic number give no effect on the thermal resistance.

• 대한인간공학회지
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• 제24권2호
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• pp.35-43
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• 2005

The purpose of this study is to suggest computer assisted neck-base's landmark identification algorithms and measurement extraction methods from three-dimensional human scan data. So we developed the algorithms for automatic identification of landmarks related to the neck-base types. The subjects were 58 women $18{\sim}24$ years of age. Their body were measured directly and indirectly by using camera and three-dimensional body scanner. They were measured during the months of October in 2001. Based on the characters of classified neck-base types, algorithms for the automatic identification of landmarks and methods of automatic measurement are developed. The three-dimensional automatic measuring program is made by $C^{++}$ language. Using this program, 4 landmarks are identified and 6 items are measured. In the verifying the precision of automatic measurement, the height measurements(cervicale, side neck point, front neck point) were relatively accurate, but neck-base width measurement was measured wide.

• 제어로봇시스템학회논문지
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• 제5권1호
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• pp.54-61
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• 1999

Objective of the research is to put the vast and complex fault tracking knowledge of human experts in semiconductor production line into the knowledge base of computer system. We mined the fault tracking knowledge of domain experts(engineers of production line) for the construction of knowledge base of the expert system. Object oriented fact models which increase the extensibility and reusability have been built. The rules are designed to perform the fault diagnosis of the items in production device. We have exploited the evidence accumulation method to assign check priority in rules. The major contribution is in the overall design and implementation of the nile base and related facts of the expert system in object oriented paradigm for the application of the system in fault diagnosis in semiconductor production line.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.834-839
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• 2004

In this paper, we investigate the optimal base position and joint configuration of a planar wheeled mobile manipulator in terms of manipulability measure. Taking into account the level of coordination between a manipulator and a platform, both local and global optimization problems are considered. First, based on the kinematic models of a mobile manipulator, the manipulability measures are expressed along with the analysis of the configurational dependency. Second, the geometric symmetry of a mobile manipulator in view of manipulability measure is analyzed, and for some base positions, the best and worst joint configurations are determined, Third, with reverence to the maximum, minimum, and average manipulability measures, the optimal base positions are determined, and the percent improvements due to the base relocation are discussed considering the relative scales among the platform size, the wheel radius, and the link length.

• 경영과정보연구
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• 제1권
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• pp.229-268
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• 1997

Recently, object-oriented concepts and technology are on the leading edge of programming language and database systems research, and their usefulness in those contexts has been successfully demonstrated. The adoption of object-oriented concept to the design of model bases has several benefits. From the perspectives of object-oriented approach, models in a model base are viewed as object which encapsulate their states and behaviors. This paper focuses on the design of an object-oriented model base that handles various resources of DSS(data, knowledge, models, solvers) in a unified fashion. For the design of a model base, we adopted Object Modeling Techniques(OMT). An object model of OMT can be used for the conceptual design of an overall model base schema. The object model of OMT provides several advantages over the conventional approaches in model base design. The main advantage are model reuse, hierarchical model construction, model sharing, meta-modeling, and unified model object management.

• 한국지반신소재학회논문집
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• 제11권3호
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• pp.11-17
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• 2012

본 논문에서는 하부층 연약지반 보강공법으로 사용되고 있는 지오셀을 이용한 투수성 도로포장의 지지력 거동 특성을 다루었다. 현장시험을 통해 지오셀 포장의 지지력 변화를 일반쇄석 포장과 비교하여 분석하기위해 FWD를 이용하여 지지력 특성을 평가하였다. 실험결과 1.5mm 두께의 지오셀의 경우 보강효과가 나타나는 것으로 측정되었으며 재하하중이 증가함에 따라 보강효과도 큰 것으로 평가 되었다.

• 한국자동차공학회논문집
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• 제19권4호
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• pp.24-31
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• 2011

Performance of the asymmetric trapezoidal fin with various upper lateral surface slopes is investigated by using the two-dimensional analytic method. For a fin base boundary condition, convection from the inner fluid to the inner wall, conduction from the inner wall to the fin base and conduction through the fin base are considered. Heat loss and fin efficiency are represented as a function of the fin base thickness, base height, inner fluid convection characteristic number, fin tip length and fin shape factor. One of the results shows that heat loss increases while fin efficiency decreases as the fin shape factor increases.