• 대한기계학회논문집
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• 제19권1호
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• pp.14-21
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• 1995

General Mechanical Structures have various and complex vibration transmission paths. In order to identify the mechanism of vibration transmission. The correct estimation of exciation forces and the exact modeling of transmission paths are required. In this paper, vector synthesis technique is employed to identify the characteristics of vibration input and it's transmission to body structure for the mounting system of a compressor in a refrigerator. Vibration reduction efficiency of each transmission path is evaluated by comparing individual vector components obtained before and after the paths from experimental research. The degree of effect is used to estimate the contribution of vibration input components to total output. And this paper presents a new technique based on simulation studies using vector synthesis dragram, by which the effects of change of the magnitude and phase of transmission paths can be predicted.

• 보존과학회지
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• 제31권1호
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• pp.65-73
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• 2015

이 연구에서는 국립고궁박물관 소장 태조어진 유소의 상태 조사와 재질 분석을 통해 다회류 유물의 이해를 돕고 보존처리 시 발생할 수 있는 변형률에 대한 안정성 검증 및 효율성을 높이고자 하였다. 유소의 재질 분석 결과 겉실은 견사, 속실은 면사, 금속사의 너비는 $500{\sim}600{\mu}m$,주성분 Copper 55wt%로 확인되었다. 또한 방울술의 형태 교정 시우려되는 변형률을 확인한 결과 1TPCM의 미만의 변형률로 안정성을 검증 하였으며, 절사된 술의 단면을 접합하기 위한 접착제 선정 실험에서는 소맥전분풀이 모든 농도에서 가장 높은 인장력을 도출하여 사용이 가장 용이하다고 판단된다. 이와 같이 유물 분석 및 실험을 토대로 보존처리 과정을 수립하였으며, 그 계획에 따라 보존처리를 실행하여 포장에 이르기 까지 처리를 완료 하였다.

• 통상정보연구
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• 제12권4호
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• pp.303-325
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• 2010

This study concerns the identification of INPR process (i.e., antecedents, timeliness in new product development (NPD) and international new product rollout (INPR) and consequences) for international new product performance. It was empirically tested by a Korean sample to verify the validity of the research framework. The results show that cross-functional integration exhibited a statistically significant and positive effect on NPD timeliness. For the rapid development of new products, evidence is mounting in favor of cross-functional integration that facilitates both the quick dissemination and utilization of information. A higher level of marketing synergy was positively associated with a higher level of NPD timeliness. These findings suggest that marketing synergy plays a key role in enhancing NPD timeliness in South Korean manufacturing companies. The results also indicate that HQ-subsidiary cooperation was positively related to INPR timeliness. More comprehensive and varied information flows between HQ and subsidiary are likely to achieve product competitive advantage and then the latter may lead to international new product launch timeliness. However, technology synergy has no significant influence on NPD timeliness, implying that Korean manufacturers' managers do not recognize technology to be a major driving force, unlike Western manufacturers' managers. The findings also indicate that the positive effects of timeliness in INPR on international new product performance. It is important note that successful achievements of international new product success are likely to rely on INPR timeliness. Importantly, the results found that products developed within planned time frames are more likely to be rolled out into multi-markets on-time, resulting in higher levels of performance than when NPD completion is delayed.

• 항공우주시스템공학회지
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• 제12권2호
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• pp.7-14
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• 2018

본 연구에서는 소형 압전유압펌프가 적용된 브레이크 시스템의 부하압 개선을 위해 체크밸브에 대한 연구를 수행하였다. 가압 과정에서 부하의 정상상태 압력은 챔버압과 부하압이 체크밸브에 작용하는 단면적 비에 영향을 받는다. 체크밸브 유로 덮개는 역류 방지를 위해 유로의 단면적보다 넓게 제작되었기 때문에 단면적 비 조절을 위해 박판 스프링 형 체크밸브에 부가질량을 부착하는 방식을 제안하였다. 부가질량 부착에 의한 부하압 개선 효과를 확인하기 위해 상용코드를 이용하여 소형 압전유압펌프가 적용된 단순 브레이크 시스템의 모델링을 수행하였다. 모델링의 검증을 위해 부가질량이 부착되지 않은 박판 스프링 형 체크밸브를 적용한 펌프의 가압 실험결과와 시뮬레이션 결과를 비교하였다. 검증된 아메심 모델링에 부가질량을 추가하였고 시뮬레이션을 통해 단면적 비 조절에 의한 고 부하압 형성 효과를 확인하였다. 부가질량 추가에 따른 소형 압전유압펌프 구성품을 새롭게 설계/제작한 후 브레이크 시스템의 가압 성능 실험을 수행하여 부하압 35% 의 성능 개선을 확인하였다.

• International Journal of Fluid Machinery and Systems
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• 제5권2호
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• pp.91-99
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• 2012

The Fighter aircraft transmission system consists of a light weight, High Speed Flexible Coupling (HSFC) known as Power Take-Off shaft (PTO) for connecting Engine gearbox (EGB) with Accessory Gear Box (AGB). The HSFC transmits the power through series of specially contoured metallic annular thin flexible plates whose planes are normal to the torque axis. The HSFC operates at high speed ranging from 10,000 to 18,000 rpm. The HSFC is also catered for accommodating larger lateral and axial misalignment resulting from differential thermal expansion of the aircraft engine and mounting arrangement. The contoured titanium alloy flexible plates are designed with a thin cross sectional profile to accommodate axial and parallel misalignment by the elastic material flexure. This paper investigates the effect of misalignment on the transmission characteristics of the HSFC couplings. A mathematical model for the HSFC coupling with misalignment has been developed for analyzing the torque transmission and force interaction characteristics. An extensive testing has been conducted for validating characteristics of the designed coupling under various misalignment conditions. With this the suitability of the model adapted for the design iteration of HSFC development is validated. This method will reduce the design iteration cycles of HSFC and can be extended for the similar development of flexible couplings.

• 드라이브 ㆍ 컨트롤
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• 제12권4호
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• pp.35-40
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• 2015

A gas spring provides support force for lifting, positioning, lowering, and counterbalancing weights. It offers a wide range of reaction force with a flat force characteristic, simple mounting, compact size, speed controlled damping, and cushioned end motion. The most common usage is as a support on a horizontally hinged automotive tail gate. However, its versatility and ease of use has been applied in many other industrial applications ranging from office equipment to off-road vehicles. The cylinder of a gas spring is filled with compressed nitrogen gas, which is applied with equal pressure on both sides of the piston. The surface area of the rod side of the piston is smaller than the opposite side, producing a pushing force. The magnitude of the reaction force is determined by the cross-sectional area of the piston rod and the internal pressure inside the cylinder. The reaction force is influenced by many design parameters such as initial chamber volume, diameter ratio, etc. In this paper, we investigated the reaction force characteristics and carried out parameter sensitivity analysis for the design parameters of a gas spring.

• Molecules and Cells
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• 제26권4호
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• pp.329-337
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• 2008

Src-family kinases are critically involved in the control of cytoskeleton organization and in the generation of integrin-dependent signaling responses, inducing tyrosine phosphorylation of many signaling and cytoskeletal proteins. Activity of the Src family of tyrosine kinases is tightly controlled by inhibitory phosphorylation of a carboxy-terminal tyrosine residue, inducing an inactive conformation through binding with its SH2 domain. Dephosphorylation of C-ter tyrosine, as well as its deletion of substitution with phenylalanine in oncogenic Src kinases, leads to autophosphorylation at a tyrosine in the activation loop, thereby leading to enhanced Src activity. Beside this phophorylation/dephosphorylation circuitry, cysteine oxidation has been recently reported as a further mechanism of enzyme activation. Mounting evidence describes Src activation via its redox regulation as a key outcome in several circumstances, including growth factor and cytokines signaling, integrin-mediated cell adhesion and motility, membrane receptor cross-talk as well in cell transformation and tumor progression. Among the plethora of data involving Src kinase in physiological and pathophysiological processes, this review will give emphasis to the redox component of the regulation of this master kinase.

• 한국전자파학회논문지
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• 제18권2호
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• pp.158-165
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• 2007

본 논문은 X-band에서 동작하는 마이크로스트립 원형 편파 $4{\times}4$ 배열 안테나의 설계와 제작에 대해 다룬다. 단일 안테나는 정사각형 패치를 사용하고 비대칭 십자 개구 결합 급전 구조를 사용하여 RHCP(Right Handed Crcularly Polarization)로 동작하도록 하였다. 기존의 배열 안테나의 소자간의 간격을 0.8 ${\lambda}_0$에서 0.45 ${\lambda}_0$로 간격을 줄여 실장 면적을 감소시켰다. 급전 선로는 시퀀셜 로테이션 분배기로 $2{\times}2$ 배열 안테나를 설계하여 양호한 이득과 축비 대역폭을 나타내었다 ${\lambda}/4$ Transformer와 T-junction 전력 분배기로 $4{\times}4$ 배열 안테나로 확장하였다. 시뮬레이션으로 확인한 결과 최대 방사 이득은 15.09 dBi로 나타났으며, 축비 대역폭은 3 dB 기준 $9.05{\sim}10.4$ GHz(13.5%)의 양호한 특성을 보였다. 제작된 $4{\times}4$배열 안테나는 10 GHz에서 측정 결과 임피던스 대역폭($VSWR{\leq}2$)은 $8.45{\sim}11.84$ GHz(33.9%)로 나타났으며, 최대방사 이득은 11.10 dBi를 얻었다. 또한 측정된 축비 대역폭은 $9.42{\sim}10.47$ GHz(10.5%)를 얻었다.

• 한국융합학회논문지
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• 제8권5호
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• pp.19-28
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• 2017

본 논문은 가상공간 제작을 위해 다수의 카메라로 영상을 촬영했을 때, 영상 특성 차이를 감소시키는 방법을 제안하였다. 각각 8 개의 본체와 렌즈를 교차 장착하여 64 개의 영상을 사용하였다. 영상 분석은 히스토그램과 픽셀 분포 값의 표준 편차를 분석 비교하였다. 분석결과, 동일 기종의 카메라임에도 불구하고, 렌즈 혹은 이미지 센서에 따라 각각 다른 영상 특성을 보여주었다. 본 논문에서는 이러한 차이를 보정하기 위해 영상의 전체 밝기 값의 분포를 조절하였다. 시뮬레이션 결과, 평균 편차가 최대 (실내 : 6.89, 실외 : 24.23) 이었으나, 시뮬레이션 진행 후 편차가 거의(실내 : 최대 0.42, 실외 : 최대 : 2.73) 없는 영상을 얻었다. 추후에는 영상 밝기 분포보다 정밀한 영상 분석 방법을 연구하고 적용할 것이다.

• 무역상무연구
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• 제12권
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• pp.65-84
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• 1999

During the past few decades, we have witnessed three approaches to overcome the legal disparities between trading countries: - determining the individual governing law in accordance with the conflict of laws principle; - unifying and harmonizing private international law into uniform rules and substantive laws under the auspices of ICC, UNCITRAL, UNIDROIT and various NGOs ; and - drafting model laws like the UNCITRAL Model Law on Electronic Commerce and promoting member countries to enact them. Against this backdrop, the United Nations Convention on Contracts for the International Sale of Goods (CISG) and the process by which it was adopted, established the benchmark for the unification of commercial law. The CISG, completed in 1980, merged civil and common law concepts and came into force in 1988 after a certain number of countries endorsed the treaty. Besides the CISG, the U.N. Limitations Convention and the UNIDROIT Principles of International Commercial Law, to name a few, have attempted to set cross-border legal norms and standards in the international business transactions. However, since the advent of computer-based commerce, there have emerged all-out efforts to establish uniform rules before national legal systems have been developed. As a consequence, the Model Law on Electronic Commerce has become a specimen legislation covering functional equivalents of paper-based writing and signature. For the credit enhancement exemplified by the Uniform Rules for Demand Guarantees (ICC Publication No.458), the UNCITRAL prepared the U.N. Convention on Independent Guarantees and Stand-by Letters of Credit, which was adopted by the U.N. General Assembly in 1995 but remains still not effective as only two countries have ratified this treaty so far. In this connection, two draft conventions underway at UNIDROIT and UNCITRAL deserve our attention as the probability of unification in the Korean Peninsula is mounting. They are to create security interests for commercial finance in moveable equipment and accounts receivable. The UCC-type security rights are regarded to be useful to enable the North Koreans with limited properties to borrow from the banks.