• Title/Summary/Keyword: Risk-Based Design

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Significant Parameters for Assessing Soil Contaminant-Leaching to Groundwater and Determining Soil Sample Size in Field Survey

  • Jeong, Seung-Woo;An, Youn-Joo
    • Environmental Engineering Research
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    • v.13 no.2
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    • pp.73-78
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    • 2008
  • For a given soil-contaminated site, a level of soil contamination is characterized and decisions on risk may be made from the risk assessment. The study evaluated critical design factors for the determination of sample size in the sampling design plan and the assessment of soil contaminant- leaching to groundwater. Two variables, the minimum relative detectable difference (T) and coefficient of variation (CV) were evaluated for the sample size determination. The minimum number of samples can be appropriately determined by CV under a T value greater than or equal to 0.2. Soil-contaminant leaching to groundwater was evaluated by using the Soil Screening Level equation of U.S. Environmental Protection Agency and the Risk Based Screening Level equation of American Society for Testing and Materials, with the same input parameters. The groundwater concentrations estimated from soil contaminant concentrations were significantly affected by the Darcy velocity of groundwater and the organic content of soil.

Development of Preventive Maintenance Plan based on PRA - Case Study of Pansong-Line Railway in Pusan - (위험도평가에 기초한 예방유지관리 계획 - 부산지하철 반송선의 설계 예 -)

  • Kim Jae-Won;Choi Young-Min;Kim Dae-Sung;Kim Kyo-Hun;Park Hyang-Woo
    • Proceedings of the KSR Conference
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    • 2005.11a
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    • pp.482-487
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    • 2005
  • In the most current Turn-key bidding and Alternative design, is going to establish maintenance plan along with a economical assessment (VE/LCC assessment etc). Generally, establishment of maintenance plan is based on past experiences that are decided upon sensor position and amount with analytic or mechanical control section. But, it is more reasonable that maintenance plan based on level of significance for Probabilistic Risk, with presuming damage probability assessment of structural fracture scenarios. Therefore, in this study it is considered about the technique that an improved maintenance plan of railroad structures using PRA (Probabilistic Risk Assessment) on the basis of structural reliability theory. For this, in the paper, Preventive maintenance plan based on PRA is suggested with an application example of Pansong-Line (Line number 3) railway in Pusan works that actually executed Turn-key design.

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Tests for equivalence/non-inferiority based on odds ratio in matched-pair design

  • Go, Hye-Jeong;Lee, Jae-Won
    • Proceedings of the Korean Statistical Society Conference
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    • 2003.10a
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    • pp.319-324
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    • 2003
  • 본 논문에서는 matched-pair design에서의 두 처리간 동등성/ 비열등성 검정에 대해 고려하였다. 기존에 비율차이나 risk ratio관점에서 동등성/비열등성 검정을 시행한 것과는 달리, 본 논문에서는 odds ratio에 기초하여 두 가지 검정통계량을 유도하였다. (1) constrained maximum likelihood estimator(mle)를 이용한 fieller type 통계량 (2) 제약없이 구한 mle를 사용한 wald-type 통계량). 비율 차이나 risk ratio에 기초한 기존의 통계적 방법들(비율차이에 근거한 (3) score-type 통계량과 (4) wald-type 통계량, risk ratio에 기초한 (5) fieller-type 통계량과 (6) wald-type 통계량)과 본 논문에서 제시한 두가지 통계량의 성능을 비교하기 위해 모의실험을 시행하였다. 모의실험 결과, 본 논문에서 제안한 constrained mle를 사용한 fieller type 통계량은 empirical type I error 측면에서 매우 만족스러운 결과를 보이고 있으며, 특히 비대각 셀의 확률이 작아질 경우에도 안정적인 성능을 보여준다.

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RAM Study for LNG Fuel Supply System (액화천연가스 연료 공급 장치에 대한 신뢰성 분석)

  • Park, Yongtae;Lee, Jaeik;Kwon, Donghyun;Lee, Changheon
    • Special Issue of the Society of Naval Architects of Korea
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    • 2013.12a
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    • pp.90-93
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    • 2013
  • RAM study has been used for various range of industry such as chemical, electronics, defense industry. Recently, in the offshore & shipbuilding industry, demand of owners to analysis risk has been increased. RAM study is a quantitative pointer to risk based design and provides effective method for improvements. This article shows the result of RAM study for LNG fuel supply system. The result provides information to improve design. This study shows how result of risk assessment affects the design of LNG fuel supply system.

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Probabilistic GMP Calculation Method based on BIM (BIM기반 확률론적 GMP 산정방안에 관한 연구)

  • Go, Gun-Ho;Jin, Zheng-Xun;Kim, Hyun-Joo;Hyun, Chang-Taek
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2018.05a
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    • pp.122-123
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    • 2018
  • Recently, CM at Risk delivery system(CM@R) that could solve the problems of Design Bid Build delivery(DBB) system has been emerging. In the CM@R delivery system, the contractor negotiates for a maximum guaranteed price(GMP) with the client at the design stage, and the contractor carries out the construction within the GMP. In CM @ R, the construction company with expertise in construction participates from the design stage to reflects the construction know-how in the design. On the other hand, the modification design frequently occurs due to the change of the construction cost when negotiating the GMP. In addition, uncertainties are inherent in the GMP calculation because the calculation is based on unfinished drawings and documents. This study proposes a probabilistic GMP estimation method applying MCS to the BIM - based cost prediction model, in order to extract the accurate quantity information when estimating the GMP and to cope with the change of the construction cost inherent in uncertainty.

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Impacts of Perceived Risks for Smart Shoes on the Purchase Intention by Types of Smart Shoess (스마트슈즈 위험지각이 스마트슈즈 유형별 구매의도에 미치는 영향)

  • Jung, Ju Ri;Oh, Kyung Wha
    • Fashion & Textile Research Journal
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    • v.23 no.1
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    • pp.84-97
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    • 2021
  • This study examines the impact of perceived risks for smart shoes based on purchase intention by type of smart shoes as well as how they are mediated by fashion innovativeness and technology innovativeness. It also compares the differences between awareness, interest and perceived risk of smart shoes by gender and age. This study was conducted based on men and women in their 20s to 50s who provided 246 samples for data analysis using SPSS 25.0. The results show significant differences in the awareness, interests and perceived economic risk of smart shoes by gender and age. The perceived performance risk had a positive effect on the purchase intention of smart shoes for GPS. Perceived aesthetic-psychological risk had a negative effect on all types of smart shoes. Perceived economic risk had a negative effect on the purchase intention of smart shoes for entertainment; in comparison, perceived social risk had a positive effect on the purchase intention of smart shoes for GPS and entertainment. Fashion innovativeness and technology innovativeness also mediated the relationship between perceived economic risk as well as the purchase intention of smart shoes for healthcare, GPS and entertainment.

Effects of Diagnosis-Related Group-Based Payment System on the Risk-Adjusted Cesarean Section Rate (Diagnosis-Related Group 지불제도가 위험도 보정 제왕절개 분만율에 미치는 영향)

  • Kwak, Jin-Mi;Lee, Kwang-Soo
    • Health Policy and Management
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    • v.31 no.2
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    • pp.180-187
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    • 2021
  • Background: This study analyzed the effect of applying the diagnosis-related group (DRG)-based payment system, which was implemented in July 2012 for hospitals and clinics nationwide, on the cesarean section rate. Methods: The subjects of the study were divided into new groups that participated in the payment system after July 2012 and maintenance groups that participated in the payment system before July 2012. As an analysis method, a difference-in-difference analysis, which is a quasi-experimental design, was used. The risk-adjusted cesarean section rate was used as a dependent variable. Results: Seven risk factors (malpresentation of fetus, eclampsia, multiple pregnancies, problems in the placenta, previous Cesarean section, cephalopelvic disproportion, problems in amniotic fluid) were included in the final risk-adjustment model, and found to have a statistically significant relationship with the cesarean section rate. Results showed that the risk-adjusted cesarean section rate increased significantly in new groups after the application of the DRG-based payment system. Conclusion: Study results provided policy implications for the reorganization of the DRG-based system should that reflects the demands of obstetricians, such as organizing a consultative body with obstetricians and establishing a reasonable fee.

Proposals on the Input Data Standardization Needs of Fire and Evacuation Simulation in Performance Based Design (성능위주 화재와 피난시뮬레이션 입력데이터의 표준화 필요성에 대한 제안)

  • Jang, Keun Ho
    • Fire Science and Engineering
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    • v.30 no.5
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    • pp.18-25
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    • 2016
  • National performance-based design methods and prescribed standards for various input data not defined as separated regulation, ASET and RSET fire and evacuation simulations on the data cited by different designers. This is also directly connected reliability problems for the evacuation simulation and performance-based fire. standardizing the various input to performance-based fire and evacuation simulations of a similar risk, regardless of the experience of designer or technical skills. The performance-based targets proper fire-fighting and emergency equipment installed reasonable initial investment cost to done ensure safety.

Risk Identification and Priority method for Overseas LNG Plant Projects - Focusing on Design Phase - (해외 LNG 플랜트 리스크요인 도출 및 우선순위 평가 - 설계단계를 중심으로 -)

  • Jang, Woo-Sik;Hong, Hwa-Uk;Han, Seung-Heon
    • Korean Journal of Construction Engineering and Management
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    • v.12 no.5
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    • pp.146-154
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    • 2011
  • Korean contractors have been maintained sustainable growth since entering into overseas construction market for the first time in 1960' s. In 2010, Korean contractors ordered 761 billion (USD) from overseas markets. Especially, billion (USD) were earned by Korean contractors in overseas plant construction market which account for more than 80% of the total amount by Korean contractors. Nevertheless, many Korean contractors are suffering from lack of technological competitiveness and construction management skills in the design phase compared with global leading contractors. These conditions have directly effect on the success of projects in terms of cost, duration, and quality. So, this study focused on identifying the risk factors and developing risk priority method for the design phase of LNG plant projects whose market is expanding. Research procedures were conducted by the following three steps. First, total 57 risk factors were identified in design phase through extensive literature reviews and experts survey. Second, the authors developed risk priority method which are more suitable for design phase of LNG plant projects by using three criteria, Probability(P), Impact(I), and Coordination Index(CI). Finally, the suitability of risk priority method and practical applicability were verified through expert survey and interview. Consequently, if korean contractors use the suggested risk factors and priority method based on their own know-how and experiences, then more reasonable and rational risk management will be conducted in the design phase of LNG plant projects.

A Study on the Risk based RAMS Assessment for Railway Rolling Stock Systems (철도차량시스템의 위험기반 RAMS 평가에 관한 연구)

  • Park, Mun-Gyu;Han, Seong-Ho
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.64 no.4
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    • pp.220-230
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    • 2015
  • Rolling stock RAMS is a field of engineering which integrates reliability, availability, maintainability and safety (RAMS) characteristics into an inherent product design property through rolling stock system engineering process. It is implemented to achieve operational objectives successfully, and recently the RAMS has become a rapidly growing engineering discipline because it has a great potential to ensure safety and improve cost effectiveness. However, the Korean rolling stock industry has not yet implemented RAMS management in the rolling stock engineering process, despite the issue having been addressed since the introduction of the KTX. Thus, this paper discusses the processes, methods and techniques for RAMS assessment in three parts. Firstly, it outlines a process of the overall RAMS performance assessment for achieving technical RAMS design criteria. Secondly, it discusses a process for assessing the operational RAM and allocating the RAM. This paper also proposes a model for assessing safety-based risk management, which includes five analytic techniques for identifying the causes and consequences of a system failure. Finally, a case example is provided for the risk assessment of the pneumatic braking device.