• Title/Summary/Keyword: Conservatism

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Development of Water Supply System under Uncertainty

  • Chung, Gun-Hui;Kim, Tae-Woong;Kim, Joong-Hoon
    • Proceedings of the Korea Water Resources Association Conference
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    • 2009.05a
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    • pp.2179-2183
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    • 2009
  • As urbanization is progressed, the network for distributing water in a basin become complex due to the spatial expansion and parameter uncertainties of water supply systems. When a long range water supply plan is determined, the total construction and operation cost has to be evaluated with the system components and parameter uncertainties as many as possible. In this paper, the robust optimization approach of Bertsimas and Sim is applied in a hypothetical system to find a solution which remains feasible under the possible parameter uncertainties having the correlation effect between the uncertain coefficients. The system components to supply, treatment, and transport water are included in the developed water supply system and construction and expansion of the system is allowed for a long-range period. In this approach, the tradeoff between system robustness and total cost of the system is evaluated in terms of the degree of conservatism which can be converted to the probability of constraint violation. As a result, the degree of conservatism increases, the total cost is increased due to the installation of large capacity of treatment and transportation systems. The applied robust optimization technique can be used to determine a long-range water supply plan with the consideration of system failure.

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Reference Stress Based Fracture Mechanics Analysis for Circumferential Through-Wall Cracked Pipes;Comparison with Pipe Test Data (참조응력 개념을 이용한 원주방향 관통균열 배관의 파괴역학 해석;실배관 실험 데이터와의 비교)

  • Huh, Nam-Su;Shim, Do-Jun;Kim, Yun-Jae;Kim, Young-Jin
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.389-396
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    • 2003
  • This paper presents experimental validation of the enhanced reference stress based J estimates for circumferential through-wall cracked pipes, recently proposed by authors. Using the pipe test data for circumferential through-wall cracked pipes, the predicted fracture initiation and maximum moments according to the proposed enhanced reference stress method are compared with experimental ones as well as predictions from the R6 method. The results show that both the R6 method and the proposed method give conservative estimates of initiation and maximum moments for circumferential through-wall cracked pipes, compared to experimental data. For longer cracks, the proposed method reduces conservatism embedded in estimated J according to the R6 method, and the resulting predictions are less conservative, compared to those from the R6 method. For shorter cracks, on the other hand, the proposed method reduces possible non-conservatism embedded in estimated J according to the R6 method, and the resulting predictions are slightly more conservative.

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Reference Stress Based Fracture Mechanics Analysis for Circumferential Through-Wall Cracked Pipes - Comparison with Pipe Test Data - (참조응력 개념을 이용한 원주방향 관통균열 배관의 파괴 역학 해석 - 실배관 실험 데이터와의 비교 -)

  • Huh, Nam-Su;Shim, Do-Jun;Kim, Yun-Jae;Kim, Young-Jin
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.27 no.4
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    • pp.638-646
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    • 2003
  • This paper presents experimental validation of the enhanced reference stress based J estimates for circumferential through-wall cracked pipes. recently proposed by authors. Using the pipe test data for circumferential through-wall cracked pipes, the predicted fracture initiation and maximum moments according to the proposed enhanced reference stress method are compared with experimental ones as well as predictions from the R6 method. The results show that both the R6 method and the proposed method give conservative estimates of initiation and maximum moments for circumferential through-wall cracked pipes, compared to experimental data. For longer cracks, the proposed method reduces conservatism embedded in estimated J according to the R6 method, and the resulting predictions are less conservative, compared to those from the R6 method. For shorter cracks, on the other hand, the proposed method reduces possible non-conservatism embedded in estimated J according to the R6 method, and the resulting predictions are slightly more conservative.

Analysis of Loss of Condenser Vacuum Accident using a Conservative Approach with a Best-Estimate Code (최적코드를 이용한 복수기진공상실 사고의 보수적 해석)

  • Jeong, Hae-Yong
    • Journal of Energy Engineering
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    • v.24 no.4
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    • pp.175-182
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    • 2015
  • A methodology to determine the most conservative initial condition based on random sampling of operation parameters is established, in which a best-estimate computer code is adopted to minimize the conservatism in code models. To validate the applicability of the suggested method, safety evaluation for a transient of loss of condenser vacuum in a pressurized water reactor is performed. One-hundred different initial conditions are generated by MOSAIQUE program automatically and the peak pressure for the most conservative case is determined from transient analyses. The safety margin obtained with the new approach is almost equivalent to the values determined with the existing methodologies. It is found that the time and human resources required for the safety evaluation could be reduced with the suggested approach.

Behavior on Clothes Care of Female Consumers by Lifestyle Groups (성인여성의 라이프스타일에 따른 의복의 세탁관리행동)

  • 배정숙;조은영;박은희
    • Journal of the Korean Home Economics Association
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    • v.39 no.6
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    • pp.1-14
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    • 2001
  • The purpose of this research is to observe the differences in consumers behavior on clothes care based on their different lifestyles and different demographic characteristics. The research surveyed 267 women of 20 years old or older living in Taegu City. SPSS package was used for data analysis and frequency, percentage, average, standard deviation, factor analysis, cluster analysis, ANOVA(analysis of valiance). and Duncan test were used The results are as follows: 1. Lifestyle factors for the research object were found as 'Consumption-oriented','family-oriented', 'Economic-oriented','Leisure-oriented','conservatism-oriented'. The categories for analysis according to these factors are classified into 5 categories, category 1 is Leisure/Family-oriented group, category 2 Consumption/Leisure avoidance-oriented group, category 3 Economy/Family Apathy-oriented group, category 4 Conservatism-oriented group, and category 5 Consumption/Innovation group. Five factors for behavior on clothes care are found, including washing method, interest in detergent, environmental behavior, washing effectiveness, and management after washing 2. Behavior on clothes care based on lifestyle groups showed a meaningful difference according to the following: Interest in detergent(p<.05 level), environmental behavior(p<.01 level), and washing effectiveness(p< .01 level) 3. In demographic variations (such as age, monthly income, monthly expenditure on clothes), there is a meaningful difference in behavior on clothes care, such as interest in detergent or management after washing, according to different age groups. However, no meaningful difference is found in behavior on clothes care according to other demographic characteristics.

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Evaluation of Plugging Criteria on Steam Generator Tubes and Coalescence Model of Collinear Axial Through-Wall Cracks

  • Lee, Jin-Ho;Park, Youn-Won;Song, Myung-Ho;Kim, Young-Jin;Moon, Seong-In
    • Nuclear Engineering and Technology
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    • v.32 no.5
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    • pp.465-476
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    • 2000
  • In a nuclear power plant, steam generator tubes cover a major portion of the primary pressure-retaining boundary. Thus very conservative approaches have been taken in the light of steam generator tube integrity According to the present criteria, tubes wall-thinned in excess of 40% should be plugged whatever causes are. However, many analytical and experimental results have shown that no safety problems exist even with thickness reductions greater than 40%. The present criterion was developed about twenty years ago when wear and pitting were dominant causes for steam generator tube degradation. And it is based on tubes with single cracks regardless of the fact that the appearance of multiple cracks is more common in general. The objective of this study is to review the conservatism of the present plugging criteria of steam generator tubes and to propose a new coalescence model for two adjacent through-wall cracks existing in steam generator tubes. Using the existing failure models and experimental results, we reviewed the conservatism of the present plugging criteria. In order to verify the usefulness of the proposed new coalescence model, we performed finite element analysis and some parametric studies. Then, we developed a coalescence evaluation diagram.

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Information Professionals Going Beyond the Needful User in Digital Humanities Project Collaboration

  • Engerer, Volkmar P.
    • Journal of Information Science Theory and Practice
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    • v.8 no.1
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    • pp.6-19
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    • 2020
  • When information professionals deal with other disciplines in the course of digital humanities projects, they often assume that they are dealing with 'needful users' who have an 'information gap' to fill. This paper argues that the traditional view that information/knowledge is transferred from an information specialist donor to a domain specialist receiver is no longer appropriate in the digital humanities context, where the gap-and-search (or gap-and-filler) approach to information has given way to more direct, explorative engagement with information. The paper asks whether information science and the practising profession are ready for this paradigm shift and examines information science conservatism in two common collaboration scenarios, library support and digital development. It is shown that information science theory still assumes a traditional donor role in both scenarios. How information scientists deal with conservatism in practice is discussed in the example of the Prior project, in which the information science team exerted an ambiguous, hybrid approach with both conservative and non-conservative elements. Finally, two rather hypothetical answers are offered to the question of how information professionals should approach scholarly collaboration in the digital humanities context, where users have ceased to be supplicants. From a purely pragmatic perspective, information scientists need to shift their focus from information needs to research practices and the implications of these practices for digital information systems. More fundamentally, the emergence of digital humanities challenges information professionals to transform information systems designed for searching into digital objects that can be explored more freely by the digital humanities community.

The Plant-specific Impact of Different Pressurization Rates in the Probabilistic Estimation of Containment Failure Modes

  • Ahn, Kwang-ll;Yang, Joon-Eon;Ha, Jae-Joo
    • Nuclear Engineering and Technology
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    • v.35 no.2
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    • pp.154-164
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    • 2003
  • The explicit consideration of different pressurization rates in estimating the probabilities of containment failure modes has a profound effect on the confidence of containment performance evaluation that is so critical for risk assessment of nuclear power plants. Except for the sophisticated NUREG-1150 study, many of the recent containment performance analyses (through Level 2 PSAs or IPE back-end analyses) did not take into account an explicit distinction between slow and fast pressurization in their analyses. A careful investigation of both approaches shows that many of the approaches adopted in the recent containment performance analyses exactly correspond to the NUREG-1150 approach for the prediction of containment failure mode probabilities in the presence of fast pressurization. As a result, it was expected that the existing containment performance analysis results would be subjected to greater or less conservatism in light of the ultimate failure mode of the containment. The main purpose of this paper is to assess potential conservatism of a plant-specific containment performance analysis result in light of containment failure mode probabilities.

The Relationship between Earnings Management and Conservatism -Focused on Earnings Loss Avoidance Firms and Big-bath Firms- (이익조정과 보수주의 -적자회피기업과 Big-bath기업을 중심으로-)

  • Park, Sang-Bong;Ra, Gi-Rye
    • Management & Information Systems Review
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    • v.32 no.5
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    • pp.261-285
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    • 2013
  • In this paper, examined relationship between Earnings Management and Conservatism. For analysis of this purpose, we applied the Earnings Loss Avoidance Firms and Big-bath Firms. The results are as follows. First, conservative of Earnings Loss Avoidance Firms(sample I, II) is lower than the controlled companies. And Big-bath firms(sample III, IV) is higher than the controlled companies. This is a negative relationship between conservative and earning management. These results are consistent with previous research results. Second, When analyzing the Earnings Loss Avoidance Firms(sample I, II), Results are presented that conservative and earning management related to positive. These results reflect the company to Investors' demand for conservatism.

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