• Title/Summary/Keyword: mitigate

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Parametric study for Welding Residual Stresses in Nozzle of Nuclear Power Plants using Finite Element Method (유한요소법을 사용한 원전 노즐 용접잔류응력의 변수해석)

  • Kim, Wan-Jae;Lee, Kyoung-Soo;Kim, Tae-Ryong;Song, Tae-Kwang
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.104-109
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    • 2008
  • Distribution of welding residual stresses are mainly characterized by degrees and frequencies of thermal loads applied to materials. However, other effects as component size and clamping condition can also affect stress distributions to a certain extent thus careful manipulation of these parameters based on clear understanding of how they affect residual stresses distributions and why can be additional measure to mitigate residual stresses. This paper discusses aforementioned issues for the case of safety and relief nozzle in nuclear power plant through finite element analysis.

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A STUDY OF FAILURE MODE, EFFECTS AND CRITICALITY ANALYSIS PROCESS FOR THE RAILROAD SYSTEM

  • Kim, Jae-Hoon;Jeong, Hyun-Yong;Cha, Dong-Wook;Park, Kwon-Shik;Park, Jun-Seo
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.1394-1400
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    • 2008
  • This study investigates the Failure Modes, Effects and Criticality Analysis (FMECA) Method for the railroad vehicle. Recently, RAMS (Reliability, Availability, Maintainability and Safety) is one of the most important issues in the railroad industry. FMECA is prerequisite for the RAMS Analysis, and it is a procedure to identify the potential failure modes and their effects and to reduce or mitigate the critical effects on the system. FMECA is used in various industries and it is specialized in each industry. For instance, MIL-1629a and SAE-J1739 are specialized FMECA method for Military industry and Automotive industry, respectively. Although the railroad industry requires the high reliability system, it does not have a specialized FMECA yet. Thus, in this paper, an FMECA method specialized to the railroad vehicle was proposed through analyses and comparison of the MIL-1629a, SAE-J1739 and IEC-60812 standards.

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Business Process Reengineering of an Information Exchange Management System for a Nationwide Cyber Threat Intelligence

  • Pramadi, Yogha Restu;Rosmansyah, Yousep;Kim, Myonghee;Park, Man-Gon
    • Journal of Korea Multimedia Society
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    • v.20 no.2
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    • pp.279-288
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    • 2017
  • Nowadays, nations cyber security capabilities play an important role in a nation's defense. Security-critical infrastructures such as national defenses, public services, and financial services are now exposed to Advanced Persistent Threats (APT) and their resistance to such attacks effects the nations stability. Currently Cyber Threat Intelligence (CTI) is widely used by organizations to mitigate and deter APT for its ability to proactively protect their assets by using evidence-based knowledge. The evidence-based knowledge information can be exchanged among organizations and used by the receiving party to strengthen their cyber security management. This paper will discuss on the business process reengineering of the CTI information exchange management for a nationwide scaled control and governance by the government to better protect their national information security assets.

Mitigating Hazards by Better Designing a Recycling Program: Lessons Learned from South Korea

  • Kim, Kyung Woo;Song, Minsun
    • Journal of Contemporary Eastern Asia
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    • v.14 no.2
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    • pp.17-36
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    • 2015
  • As an effort of mitigating hazards, pro-environmental programs have been vigorously activated with regard to solid waste recycling. It is beneficial for both the environment and resource saving, but implementation and enforcement are hard to achieve voluntarily. The South Korean Government first implemented the Deposit Refund System (DRS) and later the Extended Producer Responsibility Program (EPR) to reduce waste and encourage recycling in South Korea. Un-der the DRS, producers would pay for recycling the wastes of the products. The government then repealed the DRS and implemented the EPR program. Under this program, the producers recycle as much as the Ministry of Environment determines or pay a penalty for an excessive amount of the waste. In the broader perspective of disaster management, such policy programs can mitigate environmental hazards. This paper compares those two programs that facilitated the level of recycling, focusing on how such programs regulate producers and how they were operated from the perspective of implementation and enforcement.

How to cope with the Spaghetti Trap of multiple FTAs effectively (다양한 형태의 FTA 체결에 따른 Spaghetti Trap에 대한 효율적 대응방안)

  • Choi, Chang-Hwan
    • International Commerce and Information Review
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    • v.12 no.4
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    • pp.509-535
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    • 2010
  • This paper examines the Spaghetti bowl effect that different tariffs and rules of origin in multiple FTAs have resulted in increasing the significantly additional burden for business when it comes to apply for the use of FTA preference. The wide spread of FTAs in the several years, from 2003 to 2010, has been the most important trade policy development in economically important Korea. Korea presently has 5 FTAs in effect, and made 3 additional agreements which will be expected to take effect in next year. With the study result and expecting a growing number of FTAs in Korea in a next decade, the international trading firms will face rise of transaction costs for enterprises, particularly small- and medium-sized enterprises(SMEs) to cope with multiple tariffs and rule of origins in FTAs. To help mitigate negative effects and facilitate a more SEMs to use the FTA preference, providing new computer programs system, increasing the awareness of FTA provisions, improving business participation in FTA consultations, and SME support in light of education, and financial support are needed.

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Adaptive Leaky Factor Determination for Robust Video Transmission over Error-Prone Networks

  • Kim, Jun-Hyung;Hwang, Min-Cheol;Wang, Tae-Shick;Nam, Ju-Hun;Ko, Sung-Jea
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2009.01a
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    • pp.263-266
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    • 2009
  • When video packets are transmitted over error-prone networks, the leaky prediction can be used to mitigate the effect of error propagation. The leaky factor provides trade-off between coding efficiency and error resilience in the leaky prediction. In this paper, we propose an improved leaky prediction method where the leaky factor is adaptively determined for each frame by minimizing the estimated end-to-end distortion at the encoder. Experimental results show that the proposed method with the adaptive leaky factor shows the better performance of the error robustness as compared with the conventional method.

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A Switching Technique for Common Mode Voltage Reduction of PWM-Inverter System using the DSP320F240 (DSP320F240을 이용한 PWM-Inverter구동 시스템에서의 전도노이즈 저감을 위한 스위칭 기법)

  • Park Hyun Seok;Park Kyu Hyun;Kim Lee Hun;Han Sung Yong;Won Chung Yuen;Kim Young Real
    • Proceedings of the KIPE Conference
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    • 2002.07a
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    • pp.355-359
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    • 2002
  • Much attention has been given to EMI effects created in variable speed ac drive system. Zero switching states of inverter control invoke large common mode voltage. This paper focuses on the switching techniques to mitigate common mode voltage. This paper proposes a common-mode voltage reduction method based on sinusoidal pulse width modulation in three phase PWM inverter system. By using three carriers wave displaced by 120 degrees, it is possible to eliminate a common mode voltage pulse In one control period. Simulation and experimental results show that common mode voltages In the proposed technique are reduced more than conventional technique.

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Application of shrinkage-reduced concrete to mitigate cracks of slab in parking garages (지하주차장 슬래브 균열저감을 위한 수축저감 콘크리트 현장적용 사례)

  • Seo, Jong-Hae;Lee, Jung-Ho;Lee, Kyu-sik;Jeon, Byong-kap;Kim, Jun-Sam;Lee, Hoi-Keun
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2012.05a
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    • pp.197-200
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    • 2012
  • Concrete has cracks from shrinkage that necessarily result from in hardening process. Shrinkage-reduced concrete developed for crack reduction was utilized at a sample construction project. As a result, it is confirmed that crack initation ratio was remarkably reduced when compared to the case of normal concrete utilization. Additional sample project is supposed to use delay joints as well as srinkage-reduced concrete. Subsequently, the result will be reported. The greatest factor which affects in drying shrinkage is unit quantity of water. However, there are a lot off difficulties in field supervision because proper measuring means is not presented in present standard. Therfore, problems depending on ready-mixed concrete concrete companies should be improved by preparing the related standard assoon as possible.

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A new precharging method without side effects for liquid crystal displays with insufficient charging time

  • Lee, Seung-Hyuck;Kim, Jongbin;Lee, Seung-Woo
    • Journal of Information Display
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    • v.13 no.3
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    • pp.125-130
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    • 2012
  • In this paper, a new precharging method without any side effects is proposed to overcome image degradation caused by insufficient charging times. This work explains why the precharging method can compensate for short charging times. However, side effects of the precharging method in the form of horizontal line artifacts are addressed, wherein line artifact-compensating precharging (LCP) is presented to mitigate the side effects. Behavioral modeling is employed to investigate the side effects by estimating transient responses of a liquid crystal display. The LCP proves that it can dramatically reduce line artifacts caused by precharging because the brightness difference of adjacent pixels does not exceed 1.0.

Removal of Aoueous Pentachlorophenol by Horseradish Peroxidase in the Presence of Surfactants

  • Kim, E.Y.;Choi, Y.J.;Chae, H.J.;Chu, K.H.
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.11 no.5
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    • pp.462-465
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    • 2006
  • An important issue in the oxidation of pentachlorophenol (PCP) by the enzyme horseradish peroxidase (HRP) is enzyme inactivation during the reaction. This study was initiated to investigate the ability of two nonionic surfactants (Tween 20 and Tween 80) to mitigate HRP inactivation. The surfactants were tested at concentrations below and above their critical micelle concentrations (CMCs). Enhancement of PCP oxidation was observed at sub-CMCs, indicating effective protection of HRP by the two surfactants. Maximum levels of PCP removal were observed when the concentrations of Tween 20 and Tween 80 were 40 and 50% of the CMCs, respectively At supra-CMCs, both surfactants caused a noticeable reduction in the extent of PCP removal.