• Title/Summary/Keyword: Impact control

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형상기억 폴리우레탄을 이용한 epoxy laminate beam의 진동제어 특성에 관한 연구 (Vibration control characteristics of epoxy laminate beam utilizing shape memory polyurethane)

  • 양재흥;신규철;정용찬;조재환;전병철
    • 한국섬유공학회:학술대회논문집
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    • 한국섬유공학회 2001년도 가을 학술발표회 논문집
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    • pp.326-326
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    • 2001
  • Epoxy/glass fiber 복합재는 높은 strength와 stiffness를 갖는 장점이 있지만 impact strained energy를 효율적으로 발산시킬 수 있는 mechanism을 가지고 있지 않기 때문에 damping 능력이 떨어진다 Impact strength와 damping 성능을 증가시키기 위해 사용되어지고 있는 방법은 형상기억 고분자를 이용한 것으로 상대적으로 높은 strength와 impact에 대한 흡수 및 발산을 가지고 있다 형상기억 고분자는 glass transition temperature(G$_{g}$) 근처에서 높은 damping 능력을 가지고 있다. (중략)

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터널 내부의 도로교통소음 (Road Traffic Noise in Tunnel)

  • 여운호;유명진
    • 한국환경보건학회지
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    • 제19권4호
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    • pp.9-13
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    • 1993
  • This paper describes the impact of reflected sound in tunnel. The impact of reflected sound is obtained from making a comparision between measurements of tunnel and bridge. Sound level of tunnel is higher than that of bridge because reflected sound is generated in tunnel. Road traffic noise cannot be freely propagated because there are many buildings in urban. Therefore, a tunnel effect is generated in urban road. The impact of reflected sound is generated not only in tunnel, but also in urban road. This study provides the basic data for tunneling work and noise control strategy in urban road.

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국내산 리기다소나무를 이용한 목재 모형 사방댐의 강도 성능 평가 I (Strength Properties of Wooden Model Erosion Control Dams Using Domestic Pinus rigida Miller I)

  • 김상우;박준철;이동흡;손동원;홍순일
    • Journal of the Korean Wood Science and Technology
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    • 제36권6호
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    • pp.77-87
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    • 2008
  • 국내산 주요 침엽수 소경목의 활용 방안으로 리기다소나무를 이용한 목재 모형 사방댐을 제작하여 강도 성능을 평가하였다. 목재 모형 사방댐은 직경 90 mm의 CUAZ-2 (Copper Azole) 처리한 리기다소나무 방부 원주목을 사용하여 3 Type으로 접합부를 달리하여 제작하였다. 각 Type별 사방댐은 횡목 5층 종목 4층 총 9층의 높이 790 mm로 제작 하였으며 수평 재하 시험과 충격 시험을 통한 강도 성능 평가와 화상처리를 통한 구조물의 변형을 검토 하였다. 직경 90 mm의 원주목을 사용한 목재 모형 사방댐의 수평 재하 시험 결과 직결나사를 사용한 경우 쇄석의 유무는 강도에 큰 영향을 미치지 않았지만 변형은 23% 감소하였다. 전선볼트를 사용한 일체형 사방댐의 경우 쇄석을 채운 경우 1.5배 강도가 증가하고 변형은 감소하였다. 직결나사에 고리가 달린 전선볼트로 보강한 경우 4.8배 강도가 증가하였다. 직경 90 mm 목재 모형 사방댐의 충격 시험 결과 쇄석을 채우지 않은 직결나사 사방댐은 1회 충격에 구조물 전체가 파괴되었으며 전선볼트를 사용한 사방댐은 1회 충격시 779 kgf의 충격이 직접적으로 가해지는 횡목에서 파괴되었다. 2회 충격시 기초부가 파괴되며 545 kgf로 반력이 감소하였고 3회 충격시 기초부 전체가 파괴되며 263 kgf로 반력이 감소하였다.

Impacts of Corruption Control on Economic Growth in Relationship with Stock Market and Trade Openness

  • PHAM, Van Thi Hong
    • The Journal of Asian Finance, Economics and Business
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    • 제7권12호
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    • pp.73-84
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    • 2020
  • The study aims to investigate the dual effects of corruption control on economic growth in relationship with the stock market and trade openness in developing countries. The study used difference S-GMM method on the dynamic panel data model in the period (2002-2017) with data collected from the World Bank. The study discovers the dominant impacts of corruption control in the relationship with the stock market on economic growth. At the same time, the study also confirms the overwhelming impact of corruption control in the relationship between trade openness and economic growth in the developing countries. In addition, the study shows that inefficient stock markets in developing countries will not promote economic growth. Meanwhile, the long-standing credit market has a positive impact on economic growth. With the strong development of stock market and trade openness in the period (2002-2017), control on corruption in developing countries does not get better in time with the increase in demand. The findings of this study suggest a number of solutions to strengthen corruption control, leading to the increased efficiency on the stock market and as well as encouraging the positive effects of trade openness to contribute to promoting economic growth in developing countries.

Factors Affecting the Internal Control System: A Case Study of Chemical Enterprises in Vietnam

  • NGO, Hoang Thanh;NGUYEN, Tung Dao;NGUYEN, Nga Thuy Thi;DAO, Ha Ngoc;VU, Anh Phuong Tran
    • The Journal of Asian Finance, Economics and Business
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    • 제8권12호
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    • pp.371-376
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    • 2021
  • The article analyzes the impact of factors affecting the internal control system of chemical enterprises in Vietnam, providing more empirical evidence on factors affecting the system of internal control. Research data is collected in the form of face-to-face interviews and email interviews with managers and employees working in different positions, managers at all levels, chief accountants, and accountants of 52 chemical enterprises in Vietnam. The survey results collected 310 questionnaires. After eliminating the invalid questionnaires due to many blank cells, the authors chose to use 297 questionnaires. Quantitative research was carried out with SPSS 25 software. Research results show that Business Strategy, Organizational Structure, Organization's perception of the instability of the external environment, and Organizational culture are the factors that positively affect the internal control system of chemical enterprises. This can be explained that, for chemical enterprises, Business strategy, Organizational structure, Organization's perception of the instability of the external environment, and Good organizational culture will positively impact the internal control system of chemical enterprises. Based on the research results, the authors have proposed recommendations to enhance the effectiveness of the internal control system of chemical enterprises in Vietnam, thereby contributing to improving the performance of enterprises in the chemical Vietnamese.

Product Quality Control Activities and Repurchase Intention in Agro-product E-commerce

  • Zi-Hui BAI;Chao XU;Sung Eui CHO
    • 융합경영연구
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    • 제12권1호
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    • pp.1-15
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    • 2024
  • Purpose: This study aims to explore the critical factors in the quality control activities of agricultural products in e-commerce companies and analyze how these factors affect customers' perceived value and repurchase intention. Finally, it further reveals the mediating role of perceived value between the factors of quality control activities of agricultural products and customer repurchase intention. Research design, data and methodology: This study identified six independent factors within agricultural product quality control activities: freshness, assurance, diversity, grading, packaging, and timeliness. Subsequently, the impact of these factors on customer repurchase intention was analyzed. Additionally, perceived value was considered as an intermediary variable between the independent and dependent variables. Data was gathered from 269 Chinese consumers who had experience purchasing on agricultural product e-commerce websites. Results: The study results indicate that the relevant factors within agricultural product quality control activities strongly influence customer repurchase intention, with perceived value mediating this relationship. Conclusions: The significance of this study lies in its exploration of the relevant factors within agricultural product e-commerce's product quality control activities. It identifies their impact on customer repurchase intention and confirms the mediating role of perceived value. The results of this research offer valuable insights and practical guidance for academics in related research fields and practitioners in the agricultural product e-commerce industry.

Parameter Optimization of the LC filters Based on Multiple Impact Factors for Cascaded H-bridge Dynamic Voltage Restorers

  • Chen, Guodong;Zhu, Miao;Cai, Xu
    • Journal of Power Electronics
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    • 제14권1호
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    • pp.165-174
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    • 2014
  • The cascaded H-Bridge Dynamic Voltage Restorer (DVR) is used for protecting high voltage and large capacity loads from voltage sags. The LC filter in the DVR is needed to eliminate switching ripples, which also provides an accurate tracking feature in a certain frequency range. Therefore, the parameter optimization of the LC filter is especially important. In this paper, the value range functions for the inductance and capacitance in LC filters are discussed. Then, parameter variations under different conditions of voltage sags and power factors are analyzed. In addition, an optimized design method is also proposed with the consideration of multiple impact factors. A detailed optimization procedure is presented, and its validity is demonstrated by simulation and experimental results. Both results show that the proposed method can improve the LC filter design for a cascaded H-Bridge DVR and enhance the performance of the whole system.

Critical Factors Affecting Selection of Travel Destinations: A Case Study in Vietnam

  • TRAN, Thanh Phong;PHAN, Trong Nghia;NGUYEN, Hoang Thinh
    • The Journal of Asian Finance, Economics and Business
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    • 제8권9호
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    • pp.341-349
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    • 2021
  • This study is conducted to fill the research gap in proposing and testing the relationship between "Attitudes about the overall image of the destination", "Subjective norms" and "Perceived behavioral control". Simultaneously, we examine the relationship between these variables and tourists' "intent to choose a destination.". While most previous studies only deal with the relationship between destination image and intended behavior of tourists, this study uses the theory of planned behavior (Ajzen, 1991) to explain the intended behavior of tourists. In addition, the Theory of Destination Image (Echtner & Ritchie, 1991) is used to explain the factor "attitudes about the overall image of the destination", contribute to supplementing and perfecting the Theory of Planned Behavior. This study uses a Structural Equation Modeling (SEM) to analyze a sample of 993 observations, the subjects of which are international tourists to Vietnam, to test the relationship between second-order constructs. The test results show that "Subjective norms" and "Perceived behavioral control" have an impact on "Attitudes about the overall image of the destination". Moreover, all these three factors have an impact on "Intent to choose destination", in which the factor "Perceived behavioral control" has the greatest impact on "intention to choose destination".

이족 보행 로봇을 위한 빠르고 안전한 접촉 생성 전략 (Fast and Safe Contact Establishment Strategy for Biped Walking Robot)

  • 이호상;정재석;안준휘;박재흥
    • 로봇학회논문지
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    • 제16권2호
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    • pp.147-154
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    • 2021
  • One of the most challenging issues when robots interact with the environment is to establish contact quickly and avoid high impact force at the same time. The proposed method implements the passive suspension system using the redundancy of the torque-controlled robot. Instead of utilizing the actual mechanical compliance, the distal joints near the end-effector are controlled to act as a virtual spring-damper system with low feedback gains. The proximal joints are precisely controlled to push the mid-link, which is defined as the boundary link between the proximal and distal joints, towards the environment with high feedback gains. Compared to the active compliance methods, the contact force measurements or estimates are not required for contact establishment and the control time delay problems do not occur correspondingly. The proposed method was applied to the landing foot control of the 12-DoF biped robot DYROS-RED in the simulations. In the results, the impact force during landing was significantly reduced at the same collision speed.