• Nuclear industry
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• v.30 no.4
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• pp.22-23
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• 2010

• 도로교통
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• s.104
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• pp.24-31
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• 2006

• Proceedings of the Korea Society for Simulation Conference
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• 2004.05a
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• pp.57-62
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• 2004

그레이팅(Grating)이라는 금속제품을 생산하는 5 업체에서는 설계 자동화 시스템인 GDS(Grating automatic Drawing System)를 통해 전체 설계도면(Plan Drawing)을 생성하고 GDS의 도면자료 자동생성 시스템(ASGS: Automatic Specification Generation System)을 통해 전체 도면상에 배치된 각각의 그레이팅에 대한 상세한 정보가 표현된 단품별 도면과 완성된 제품들에 대한 검사 기준을 표현한 검사도면을 생성하며 전체 제품에 대한 통계적인 정보를 생성한다. 그러나 도면자료 자동생성 시스템을 통해 자동 생성된 도면은 설계자들의 일반적인 치수 기입요령을 부분적으로 만족시키지 못하고 있으며 또 치수 표시간의 겹침 현상이 발생하여 설계자가 도면을 수정해야하는 번거로움이 있었다. 본 논문은 이러한 문제점을 해결하기 위해, 설계 전문가들의 치수 표시법을 지식으로 하는 규칙 기반 전문가 시스템을 구성하였다.

• The Science & Technology
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• no.12 s.415
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• pp.35-37
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• 2003

기존 블라스팅 대체하는 프로세스로 특허/ 그레이팅 쉬어로그라피 기술 개발/ 갈릴레오 항행위성시스템 실현 임박/ 세계최초 신생혈관 억제제 개발

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.5
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• pp.806-812
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• 2000

In this paper, we theoretically studied on the large antenna array whose element had wider than one wavelength. And we also verified the adaptedness through the experiments. Using grating lobes, we could make antenna have sharp HPBW. Not only HPBW but also SLL could be controlled by giving optimal space for antenna array. In order to verify this method, we designed 4 horn antenna array and measured the radiation patterns at 9 GHz. Each horn antenna has the dimension of 64.3$\times$82.5$\textrm{mm}^2$ and HPBW of 27$^{\circ}$. The space between antennas is longer than one wavelength so that it may have the grating lobes in visible region. As a result of experiments, we could get HPBW of 4.3$^{\circ}$, 3.3$^{\circ}$ and 1.7$^{\circ}$when giving 2.5λ, 2.7λ and 3.0λ of the spacing respectively. We concluded this could be useful making the antenna with narrow HPBW.

• The Journal of the Acoustical Society of Korea
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• v.35 no.6
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• pp.452-465
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• 2016

In this study, the structure of a concave annular array transducer was optimized to generate high intensity focused ultrasound for medical therapeutic application. The transducer has a phased array structure composed of several concentric channels that have 40 mm as the radius of curvature. We derived theoretical equations to analyze the sound field of the transducer and verified the validity of the equations by comparing the results calculated by the equations with those from finite element analyses. We also checked the possibility of dynamic focusing at around the geometric focal point. Further, the level of a grating lobe occurring at an unwanted position in the transducer sound field was confirmed to be reducible through the relation between the number of channels and the frequency of the transducer. Hence, the structure of the transducer was optimized to place the main lobe within a specific range from the zenith while systematically reducing the level of the maximum sidelobe including the grating lobe. The designed structure showed the performance better than that targeted at all the focal points.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.05a
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• pp.269-272
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• 2003

그레이팅이라는 금속제품의 자동 설계 시스템인 GDS (Grating automatic Drawing System)는 기본 설계 도면(Plan Drawing)의 정보들을 바탕으로 여러 세부 도면들을 자동 생성하는 시스템이다. 그러나 GDS를 통해 자동 생성된 도면은 설계자들의 일반적인 치수기입 요령을 부분적으로 만족시키지 못하고 있으며 또 치수 표시간의 겹침 현상이 발생하여 설계자가 도면을 수정해야 하는 번거로움이 있었다. 본 논문은 이러한 문제점을 해결하기 위해, 설계 전문가들의 치수 표시법을 지식으로 하여 규칙 기반 전문가 시스템을 구성하였다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.2
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• pp.287-296
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• 2019

In recent years, a number of long span cable-stayed pedestrian bridges have been constructed to the advantages of relatively low cost construction and the many tourists visiting. However, most of the pedestrian bridges are located in parks or sightseeing areas, so they are conducted without proper review and design process. It is necessary to review the aerodynamic stability of the long span cable-stayed pedestrian bridge, and it should be designed in detail from various points of view rather than the road bridge. In this study, we investigated the wind characteristics of the cable-stayed pedestrian bridge, and the empirical equations for the relationship between the main span length and the fundamental natural frequencies are presented for future use. In addition, the flutter wind speed limit of the flat plate deck pedestrian bridge calculated using the Selberg's equation is also presented. The final aerodynamic bridge section which satisfied the aerodynamic stability was found from open grating method. The proposed method can be used for long span cable-stayed pedestrian bridge in the future.

• Journal of Internet Computing and Services
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• v.21 no.4
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• pp.1-8
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• 2020

In order to reach Ultra-Reliable Low-Latency communication, one of 5G aims, Multi-access Edge Computing paradigm was born. The idea of this paradigm is to bring cloud computing technologies closer to the network edge. User services are hosted in multiple Edge Clouds, deployed at the edge of the network distributedly, to reduce the service latency. For mobile users, migrating their services to the most proper Edge Clouds for maintaining a Quality of Service is a non-convex problem. The service migration problem becomes more complex in high mobility scenarios. The goal of the study is to observe how user mobility affects the selection of Edge Cloud during a fixed mobility path. Mobility-Aware Service Migration (MASM) is proposed to optimize service migration based on two main parameters: routing cost and service migration cost, during a high mobility scenario. The performance of the proposed algorithm is compared with an existing greedy algorithm.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.71-74
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• 2007

The objective of this presentation is to introduce a recent development of a magnetostrictive grating technique using an optimal yoke to efficiently generate and measure SH (Shear-Horizontal) waves in a plate. Gratings are effective means to generate frequency-tuned waves, but the gap between magnetostrictive gratings inevitably obstructs magnetic flow. Because magnetic field is the main physical quantity to actuate and sense ultrasonic waves, the transducer performance is most significantly influenced by the magnetic field distribution in the strips. Thus, wave transduction efficiency can be substantially improved if better magnetic flow is formed in the strips. To improve the efficiency, the topology optimization method was used to determine an optimal yoke configuration. A series of experiments on an aluminum plate were conducted using a grating with and without the designed yoke; when the yoke was used, the signal outputs increased up to 60 %.