• Title/Summary/Keyword: K-joint 중요 요소

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Activation Factors of Industry Cooperation through Comparison Study on Domestic and International Industry Cooperation Programs (국내외 산학협력프로그램 비교를 통한 산학협력 활성화 방안 연구)

  • Kim, Hye Sun;Kim, Jong Boo;Kim, Hyoung Ro
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.9 no.2
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    • pp.187-200
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    • 2014
  • Industry Cooperation is not the choice of national development but the inevitable component in the world. Industry cooperation results of the reconstruction of the country is an important place as an essential element of the economic development of the national policy in the major economies. Despite several changes in the international economic environment, United States, Canada, Finland, Sweden, Israel settled and maintaining the sustainable development of the countries which successfully established Industry-University Cooperation or Industry-Acaemy Cooperation system in history. In this study, delivered to the realistic ways of Industry cooperation through comparison study on domestic and international cooperation programs. The new activation programs of industry academic cooperation are delivered, that is, The bonus payments system of technology development patent and free technology transfer for joint development, bonus points system and evaluation indicators for joint capacity building program which participate student, industry and academic sector, step-by-step training. system for total employment and entrepreneurship at the same time strengthening management training programs and education opportunity gives to the benefits for the community members. Finally, Intellectual property expert matching program which develops basis of technology trader and expert maps in the smallest unit by administrative area. practice the internet information search services in national wide network for this matching program and government office dedicated to staffing for technology transfer.

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Optimal Design of Wind Turbine Tower Model Using Reliability-Based Design Optimization (신뢰성 기반 최적설계를 이용한 풍력 발전기 타워 최적 설계)

  • Park, Yong-Hui;Park, Hyun-Chul
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.38 no.5
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    • pp.575-584
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    • 2014
  • In this study, the NREL 5 MW wind turbine tower model was optimized according to the multi-body dynamics and reliability-based design. The mathematical model was defined as a link-joint system including dynamic characteristics derived from Timoshenko's beam theory. For the optimization problem, the sensitivities to variations in the tower thicknesses and inner and outer diameters were acquired and arranged in terms of safety and efficiency according to bending stress and buckling standards. An optimal design was calculated with the advanced first-order second moment method and used to define a finite element model for validation. The finite element model was simulated by static analysis. The relationship between the multi-body dynamic and finite element method throughout the process was investigated, and the optimal model, which had high endurance despite its low mass, was determined.

Reliability Prediction of Failure Modes due to Pressure in Solid Rocket Case (고체로켓 케이스 내압파열 고장모드의 신뢰도예측)

  • Kim, Dong-Seong;Yoo, Min-Young;Kim, Hee-Seong;Choi, Joo-Ho
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.27 no.6
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    • pp.635-642
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    • 2014
  • In this paper, an efficient technique is developed to predict failure probability of three failure modes(case rupture, fracture and bolt breakage) related to solid rocket motor case due to the inner pressure during the mission flight. The overall procedure consists of the steps: 1) design parameters affecting the case failure are identified and their uncertainties are modelled by probability distribution, 2) combustion analysis in the interior of the case is carried out to obtain maximum expected operating pressure(MEOP), 3) stress and other structural performances are evaluated by finite element analysis(FEA), and 4) failure probabilities are calculated for the above mentioned failure modes. Axi-symmetric assumption for FEA is employed for simplification while contact between bolted joint is accounted for. Efficient procedure is developed to evaluate failure probability which consists of finding first an Most Probable Failure Point(MPP) using First-Order Reliability Method(FORM), next making a response surface model around the MPP using Latin Hypercube Sampling(LHS), and finally calculating failure probability by employing Importance Sampling.

A Study on electrical and mechanical reliability assessment of Sn-3.5Ag solder joint (Sn-3.5Ag BGA 솔더 조인트의 전기적, 기계적 신뢰성에 관한 연구)

  • Sung, Ji-Yoon;Lee, Jong-Gun;Yun, Jae-Hyeon;Jung, Seung-Boo
    • Proceedings of the KWS Conference
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    • 2009.11a
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    • pp.80-80
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    • 2009
  • 패키징 구조의 발전이 점차 중요한 문제로 대두되어, 칩의 집적 기술의 발전에 따라 실장기술에서도 고속화, 소형화, 미세피치화, 고정밀화, 고밀도화가 요구되고있다. 최근 선진국을 중심으로 전자 전기기기 및 부품의 실장기술에서도 환경 친화적인 기술을 요구함에 따라, 저에너지 공정 및 무연 실장 기술에 대한 연구가 활발하게 진행되고 있다. 기존의 SOP(Small Out-line Package), QFP(Quad Flat Package) 등은 소형화, 다핀화, 고속화, 실장성에 한계가 있기 때문에, SMT(Surface Mount Technology) 형식으로 된 BGA(Ball Grid Array)가 휴대형 전화를 비롯한 기타 전자 부품 실장에 널리 사용되고 있다. BGA ball shear 법은 BGA 모듈의 생산 및 취급 중에 발생할지도 모르는 기판에 수평으로 작용하는 기계적인 전단력에 BGA solder ball이 견딜 수 있는 정도를 측정하기 위해 사용되는 시험법이다. 전단 시험에 의한 전단 강도의 측정 외에 전기전도도 측정, 파면 관찰, 이동거리(displacement), 유한요소 해석법 등을 병행하여 시험법의 신뢰성 향상에 대한 연구가 이루어지고 있다. 본 실험에서는 지름이 $500{\mu}m$인 Sn-3.5Ag 솔더볼을 이용하여 세라믹 기판을 접합하여 BGA 패키지를 완성하였다. 상부 기판에 솔더볼을 정렬시켜 리플로우 방법으로 접합 한 후 솔더볼이 접합된 상부 기판과 하부 기판을 접합 하여 시편을 제작하였다. 접합된 시편들은 $150^{\circ}C$에서 0~800시간 열처리를 실시하였고, 열처리를 하면서 각각 $3{\times}10^2A/cm^2,\;5{\times}10^3A/cm^2$의 전류를 인가하였다. 시편들을 전단 시험기를 이용하여 솔더볼의 기계적 특성 평가를 하였으며, 계면 반응을 관찰하였다.

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Multi-target Data Association Filter Based on Order Statistics for Millimeter-wave Automotive Radar (밀리미터파 대역 차량용 레이더를 위한 순서통계 기법을 이용한 다중표적의 데이터 연관 필터)

  • Lee, Moon-Sik;Kim, Yong-Hoon
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.37 no.5
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    • pp.94-104
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    • 2000
  • The accuracy and reliability of the target tracking is very critical issue in the design of automotive collision warning radar A significant problem in multi-target tracking (MTT) is the target-to-measurement data association If an incorrect measurement is associated with a target, the target could diverge the track and be prematurely terminated or cause other targets to also diverge the track. Most methods for target-to-measurement data association tend to coalesce neighboring targets Therefore, many algorithms have been developed to solve this data association problem. In this paper, a new multi-target data association method based on order statistics is described The new approaches. called the order statistics probabilistic data association (OSPDA) and the order statistics joint probabilistic data association (OSJPDA), are formulated using the association probabilities of the probabilistic data association (PDA) and the joint probabilistic data association (JPDA) filters, respectively Using the decision logic. an optimal or near optimal target-to-measurement data association is made A computer simulation of the proposed method in a heavy cluttered condition is given, including a comparison With the nearest-neighbor CNN). the PDA, and the JPDA filters, Simulation results show that the performances of the OSPDA filter and the OSJPDA filter are superior to those of the PDA filter and the JPDA filter in terms of tracking accuracy about 18% and 19%, respectively In addition, the proposed method is implemented using a developed digital signal processing (DSP) board which can be interfaced with the engine control unit (ECU) of car engine and with the d?xer through the controller area network (CAN)

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Studies on the Main Level-Grading Factors for Establishment of LFQC (Liquid Fertilizer Quality Certification) System of Livestock Manure in Korea (가축분뇨 액비품질인증제도 구축을 위한 목표요소에 관한 연구)

  • Jeon, Sang-Joon;Kim, Soo-Ryang;Kim, Dong-Gyun;Rho, Kyung-Sang;Choi, Dong-Yoon;Lee, Myung-Gyu
    • Journal of Animal Environmental Science
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    • v.18 no.2
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    • pp.111-122
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    • 2012
  • Establishment of the LFQC (Liquid Fertilizer Quality Certification) system is very urgent issue for recycling livestock manure as renewable resources in Korea faced with environmental problem of manure application to land due to intensive livestock farming. In this study, we investigated relevant laws and regulations on livestock manure fertilizer, certifications of eco-friendly agricultural products, government policies on livestock manure management to establish reasonable direction of Korean LFQC (Liquid Fertilizer Quality Certification) system. As a result from this study, the liquid fertilizers in 'LFQC' system could be classified as three levels according to the usage patterns in field; 1st. Individual Farm Level (IFL), 2nd. Joint Farm Level (JFL), and 3rd. Commercial Level (CML). And finally, we found some characteristics in 'Main Level-Grading Factors' of liquid fertilizer such as fertilizing value, harmfulness, stability, uniformity, economic effect, storage potential, commercial value, functionality. Those items were considered to be the key factors for the establishment of 'LFQC' system. More research on 'Evaluation Standards' for concrete guideline and on the 'Main Level-Grading Factors' be needed to complete Korean LFQC system.

Potential as a Geological Field Course of Mt. Geumdang located in Gwangju, Korea (광주광역시에 위치한 금당산의 지질학습장으로서 활용성)

  • Ahn, Kun Sang
    • Journal of the Korean earth science society
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    • v.34 no.3
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    • pp.235-248
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    • 2013
  • The purpose of this study is to investigate a feasibility of a small mountain as a field work site on geological features in Earth sciences classes at all levels. Mt. Geumdang with the height of 305 meters from the sea level is located in the metropolitan city of Gwangju, southern part of Korea. The study reviews the human and natural geography, geological features, geomorphic resources, landscapes, and conveniences of the mountain for a possibility of meaningful field work. The population within the distance of 5 km from the mountain stands at about 620,000 and 170,000 of them are students and teachers. Mt. Geumdang has a warm temperature climate with low rainfall throughout the year, so it seems suitable for a field survey. Road network and public transportation system around the area are well-developed and easily accessible. Mt. Geumdang shows various rock type and geological structures. The basement rock is Gwangju granite, which is plutonic body of the Jurassic period. Also, granophyre (micrographic granite) and various volcanic rocks distributed as bedded tuff, lapilli tuff, and rhyolite of the Cretaceous period. Many andesitic and felsic dykes were intruded into the rock by joint system. In Mt. Geumdang, many geomorphic resources are found such as U shaped mountain, joint, fault, lamination, gnamma, tor, cliff, groove, block stream and block field, regolith, and saprolite. It has a beautiful mountain scenery including the view of whole shape of Mt. Mudeung, panoramic view of the town, Pungam lake, World Cup stadium and sunrise and sunset. Furthermore, the area has ecologic study facilities related to geology, emergency medical and convenience facilities for field works. In conclusion, Mt. Geumdang is highly feasible for geological field studies at all levels.

Performance Analysis of Screen Contents Coding Tools to Reduce Inter-Color Component Correlation (색 공간 내 중복 정보 감소를 위한 HEVC 스크린 콘텐츠 부호화 기법 성능 분석)

  • Kang, Je-Won
    • Journal of Broadcast Engineering
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    • v.20 no.5
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    • pp.687-696
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    • 2015
  • JCT-VC (Joint Collaborative Team on Video Coding) continues developing HEVC/Screen Content Coding (HEVC/SCC) as an extension for efficiently coding screen content videos, including computer animations, graphics, and electrical documents, based on HEVC/Range extension (HEVC/RExt.). Color space conversion from RGB space being captured from CCD sensors is popular in natural video coding. However, the conversion is often undesired for screen contents because of a significant loss in perceptual quality. Therefore, several coding tools including cross-component prediction (CCP) and in-loop adaptive color space transform (ACST) have been developed for an efficient screen content video coding in order to reduce the redundancies between color spaces while maintaining the original color space. In this paper, we review the two coding tools, i.e., CCP and ACST exploiting the correlation in the RGB color space and conduct the performance analysis of the coding tools. In our simulation results, CCP and ACST provide 11.7% BD-rate saving and 16.4% BD-rate saving, respectively, while the two coding tools provide 18.2% BD-rate saving in total. Following this idea, if the two coding tools are exclusively selected, we provide 93% encoding measurement time with a 0.3% coding loss.

Evaluation on Structural Performance of Joint with Asymmetric Ribbed Connection Details used in Precast Bridge Deck (비대칭 격벽단면을 갖는 프리캐스트 바닥판 이음부의 구조성능 평가)

  • Chung, Chul-Hun;Byun, Tae-Kwan;Kim, In-Gyu;Shin, Dong-Ho;Lee, Han-Joo
    • Journal of the Korea Concrete Institute
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    • v.29 no.2
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    • pp.159-167
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    • 2017
  • A precast concrete deck system is considered an effective alternative in terms of its rapid construction and quality assurance than cast-in-place concrete deck. In precast concrete deck system, structural performance and serviceability are mostly determined by the connection methods between the precast decks. This research proposes more improved precast deck system with asymmetric ribbed connection details improving the disadvantage of previous precast deck system such as difficulties in assembling precast decks. And in this precast deck system, a separate form is not required at the site because partition wall of the precast decks serves as a form when placing non-shrinkage mortar in the connection part of the precast decks. Therefore, rapid construction is possible. Flexural performance is verified through load tests considering main parameter such as rib length in the precast deck connection. From the test results, it can be inferred that the development of the rebar and prevention of adhesion failure in the partition wall of the precast deck system are important factors in securing the flexural performance. Although the structural performance of the precast deck system with asymmetric connection details is gradually reduced as the rib length in the precast deck connection increases, the proposed precast deck system shows sufficient flexural performance and can be applied to the connection part of precast decks effectively.

Structural Integrity Assessment of High-Strength Anchor Bolt in Nuclear Power Plant based on Fracture Mechanics Concept (원자력발전소 고강도 앵커 볼트의 파괴역학적 건전성평가)

  • Lim, Eun-Mo;Huh, Nam-Su;Shim, Hee-Jin;Oh, Chang-Kyun;Kim, Hyun-Su
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.37 no.7
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    • pp.875-881
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    • 2013
  • The failure of a bolted joint owing to stress corrosion cracking (SCC) has been considered one of the most important structural integrity issues in a nuclear power plant. In this study, the failure possibility of bolting, which is used to support the steam generator of a pressurized water reactor, owing to SCC and brittle fracture was evaluated in accordance with guidelines proposed by the Electric Power Research Institute, which are called the Reference Flaw Factor method. For this evaluation, first, detailed finite element stress analyses were conducted to obtain the actual nominal stresses of bolting in which either service loads or bolt preloads were considered. Based on these nominal stresses, the structural integrity of bolting was addressed from the viewpoints of SCC and toughness. In addition, the accuracy of the EPRI Reference Flaw Factor for assessing bolting failure was investigated using finite element fracture mechanics analyses.