• Title/Summary/Keyword: conservatism

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Modified adaptive complementary sliding mode control for the longitudinal motion stabilization of the fully-submerged hydrofoil craft

  • Liu, Sheng;Niu, Hongmin;Zhang, Lanyong;Xu, Changkui
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.11 no.1
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    • pp.584-596
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    • 2019
  • This paper presents a Modified Adaptive Complementary Sliding Mode Control (MACSMC) system for the longitudinal motion control of the Fully-Submerged Hydrofoil Craft (FSHC) in the presence of time varying disturbance and uncertain perturbations. The nonlinear disturbance observer is designed with less conservatism that only boundedness of the derivative of the disturbance is required. Then, a complementary sliding mode control system combined with adaptive law is designed to reduce the bound of stabilization error with fast convergence. In particularly, the modified complementary sliding mode surface which contains the estimation of the disturbance can reduce the switching gain and retain the normal performance of the system. Moreover, a hyperbolic tangent function contained in the control law is utilized to attenuate the chattering of the actuator. The global asymptotic stability of the closed-loop system is demonstrated utilizing the Lyapunov stability theory. Ultimately, the simulation results show the effectiveness of the proposed approach.

FALCON code-based analysis of PWR fuel rod behaviour during RIA transients versus new U.S.NRC and current Swiss failure limits

  • Khvostov, G.;Gorzel, A.
    • Nuclear Engineering and Technology
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    • v.53 no.11
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    • pp.3741-3758
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    • 2021
  • Outcomes of the FALCON code analysis-related part of the STARS-ENSI Service Project on Evaluation of the new U.S.NRC RIA Fuel Safety Criteria and Application to the Swiss Reactors are presented. Substantial conservatism of the updated safety limits for high-temperature and PCMI cladding failure, as proposed in the NRC Regulatory Guide RG 1.236, is confirmed. Applicability of the updated failure limits to fuel safety analysis in the Swiss PWRs, as applied to standard fuel designs using UO2 fuel pellets and SRA Zry-4 as cladding materials is discussed. Conducting of new integral RIA tests with irradiated samples using doped- and gadolinia fuel pellets to support appropriate fuel safety criteria for RIA events is recommended.

Analysis of MBLOCA and LBLOCA success criteria in VVER-1000/V320 reactors: New proposals for PSA Level 1

  • Elena Redondo-Valero;Cesar Queral;Kevin Fernandez-Cosials;Victor Hugo Sanchez-Espinoza
    • Nuclear Engineering and Technology
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    • v.55 no.2
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    • pp.623-639
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    • 2023
  • The specific configuration of the safety systems in VVER-1000/V320 reactors allows a comprehensive study of the Loss of Coolant Accident (LOCA). In the present paper, a verification of the success criteria of the event trees headers for the medium and large break LOCA sequences is conducted. A detailed TRACEV5P5 thermal-hydraulic model of the reactor has been developed, including all safety systems. When analyzing the results of all sequences, some conservatism is observed in certain specific configurations as the success criterion of some headers is not consistent with the classic PSA level 1. Therefore, new proposals for the LOCA event trees are performed based on a reconfiguration of LOCA break ranges and the use of the expanded event trees approach.

Assessment of seismic design coefficients for composite special moment frames with reinforced concrete columns and steel beams: Evaluation of code recommendations

  • Elmira Tavasoli Yousef Abadi;Mohammad T. Kazemi
    • Steel and Composite Structures
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    • v.50 no.6
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    • pp.643-658
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    • 2024
  • The main aim of this study is to quantify the code seismic design coefficients of the RCS system, which consisted of reinforced concrete columns and steel beams, based on the FEMA P-695 methodology. The underlying intention is to evaluate the seismic performance of the RCS system at the system level rather than the connection level. A set of 24 archetype buildings with a various number of stories, beam span lengths, gravity load levels, and seismic load levels are selected and designed based on the prevailing code requirements. Nonlinear analytical models are developed and validated by experimental tests. The pushover and response history dynamic analyses are conducted to evaluate the required data in the performance quantification process. The results show that the design coefficients suggested by the code are acceptable. However, the level of conservatism is very high. Thus, it is possible to use a larger R-factor in the design process or make some relaxations in the design requirements related to this structural system.

Dong-Mu Lee Je-Ma and The Rising of Choi Moon-Hwan (동무(東武) 이제마(李齊馬)와 최문환(崔文煥)의 난(亂))

  • Park, Seong-sik
    • Journal of Sasang Constitutional Medicine
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    • v.9 no.2
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    • pp.39-55
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    • 1997
  • Purpose : Dong-Mu(東武) Lee Je-Ma(李濟馬) was designated as a member of fifty persons 'The Wise Ancestors of Korean Culture and Art' in 1984 and the december of 1996 was appointed as 'The Month of Lee Je-Ma'. Though his achivements was valued like this, some historian criticized that he suppressed the righteous army. So this study was for clarifing the background, the motive, and the course of 'The Rising of Choi Moon-Hwan' occurred in Hamhung on february in 1896, and for the correct appraisement about this event. And also through this, author tried to make clear the origin of Lee Je-Ma's thought. Method : After studing the background of the end of Chosun dynasty and the righteous army in 1895(乙未義兵). Author made a comparative study through the historical materials of the goverment side, the Choi Moon-Hwan side, and the Lee Je-Ma side about 'The Rising of Choi Moon-Hwan' occurred in Hamhung on februrary in 1896. Results & Conclusion : The event occurred in Hamhung on february in 1896 was a part of rebellion of the righteous army in 1895 which had risen against The startling Occurrence of 1895'(乙未義兵) and 'The Royal Commands To Cut Off People's Hair'(斷髮令). Lee Je-Ma suppressed the Rising and put Choi Moon-Hwan in the prison, and which was criticized that he suppressed the righteous army later day. That time was a conflict period between conservatism and civilization, and the Lee Je-Ma's act was the best way to protect the security of residents from the attack which maybe occurred by Japanese army in Wonsan. Judging from this events, author could find Lee Je-Ma's thought was quite different from righteous army's neo-confucianism and conservatism. In the aspect of the history of 'Korean National Movement', further study about Choi Moon-Hwan, the chief of righteous army will be need.

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Comparison of Domestic and Foreign Design Standards for Overall Stability of Soil Nailed Slopes (쏘일네일 보강 비탈면의 전체 안정성에 대한 국내외 설계기준 비교)

  • Kim, Tae-Won;You, Kwang-Ho
    • Journal of the Korean GEO-environmental Society
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    • v.20 no.6
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    • pp.5-13
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    • 2019
  • The international trend in soil nailed wall design has been evolved from the allowable stress design to limit state design and it is still currently ongoing. The design guidelines in Korea and Hong Kong still adopts the allowable stress design philosophy while those in others mostly do the limit state design. In this study, four soil nail design methods presented in the major design guidelines (U.S. FHWA GEC 7 (2015), Clouterre in France (1991), Soil nailing - best practice guidance in U.K. (CIRIA, 2005), Geoguide 7 in Hong Kong (2008) and Design standard for slope reinforcement work in Korea (KDS 11 70 15 f: 2016)) are described and analyzed in brief. The factor of safety and CDR (Capacity-to-Demand Ratio) which is used to measure the degree of conservatism of a design guide are obtained for the two cases. One is the design example presented in CIRIA (2005) and the other is in-situ loading test performed on the top of backfill of the soil nail wall to investigate the conservatism of design guidelines. It is revealed that the design method in overall stability of soil nail walls in domestic design method (CDR=0.78) is the most conservative and those by Clouterre (CDR=0.99, 1.09), Geoguide 7 (CDR=1.13, 0.97), U.S. FHWA (CDR=1.09, 1.07) and CIRIA (CDR=1.40, 1.16) in order from the second most conservative to the least conservative for the design example presented in CIRIA. For the in-situ loading test performed on the top of backfill of the soil nail wall, the order of conservatism is identical except that the places of Geoguide 7 (CDR=0.66, 0.72) and FHWA (CDR=0.73, 0.72) are changed. However, the results obtained among U.S. FHWA (2015) and Clouterre (1991) and Geoguide 7 (2008) are not so different.

A Study on the Effect of the Thematic Audit Review on Conservative Accounting of Unbilled Revenue (테마감리가 미청구공사의 보수적 회계처리에 미치는 영향에 관한 연구)

  • Park, Yeon Ho;Um, Jae Yeon;Jeon, Seong Il
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.16 no.2
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    • pp.177-188
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    • 2021
  • On December 2015, Financial Supervisory Service(FSS) announced the four key thematic audit review areas, one of them is an appropriation of unbilled revenue. Accounting of unbilled revenue is intertwined with a percentage of completion, that is concerned about discretionary decision by manager. Therefore, if manager motivated by income-increasing manipulation is exaggerating percentage of completion, unbilled revenue is excessively recognized. This problem is caused the serious accounting issues(e.g., shock at a loss for 2013 fiscal year by some construction firms, malpractice of accounting in order-made production industry). Distrust of accounting was grown because the shipbuilding and construction industries successively went poor management and bad accounting of them is revealed. Those accounting issues were the trigger for problem recognition of unbilled revenue, they were background for the designation of appropriation unbilled revenue as thematic audit review areas by FSS. Therefore, this study verified effectiveness of thematic audit review by empirically analyzing whether designation of thematic audit review makes the firm increases conservative behavior. Conservative accounting is estimated by using Basu(1997) model. We analyzed the effect of the thematic audit review on conservative accounting of unbilled revenue by comparing with reflecting unbilled revenue or not. The sample for test consists of firm-years the manufacturing and construction industries from 2012 to 2017. The test results of this study suggested that the conservative accounting of unbilled revenue after designation of the thematic audit review was significantly increased. We also tested again by classifying whether or not it is construction industry. We found that construction industry is more conservative than the other industry only for the designated year of the thematic audit review, otherwise there was not any evidence for significantly increasing conservatism. This study contributes to the literature by empirically analysing relationship of the unbilled revenue to the thematic audit review from the perspective of the conservatism and verifying effectiveness of the thematic audit review.

Conservativeness of Response Displacement Method used in Seismic Response Analysis of Power Cable Tunnels (전력구의 지진응답해석법에 사용되는 응답변위법의 보수성 평가)

  • Lim, Jae-Sung;Yang, Dae-Seung;Hwang, Kyeong-Min;Kim, Jae-Min
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.34 no.4
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    • pp.243-254
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    • 2021
  • In this study, the conservatism of the response displacement method (RDM) for the seismic response analysis of box-shaped power cable tunnels was evaluated. A total of 50 examples were used considering the cross-sections of 25 power cable tunnels and two soil conditions for each power cable tunnel. The following three methods were applied for the analysis by the RDM: (1) single cosine method, (2) double cosine method, and (3) dynamic free-field analysis method. A refined dynamic analysis method considering soil-structure interaction (SSI) was employed to compare the conservatism of the RDM. The double cosine method demonstrated the most conservative result, while the dynamic free-field analysis method yielded the least deviation. The soil stiffness reduction factor, C, for the double cosine method was recommended to be 0.9 and 0.7 for the operational performance and collapse prevention levels, respectively, to ensure a probability of at least 80% that the member force by the RDM is larger than that of dynamic SSI analysis.

Substantive Representation of Women Under the Conservative Government in Japan: An analysis of the Diet deliberation of the Bill on Promotion of Women's Participation and Advancement in the Workplace (日本の保守政権下における女性の実質的代表-女性活躍推進法案を巡る国会審議をケースとして)

  • Osawa, Kimiko
    • Analyses & Alternatives
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    • v.5 no.1
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    • pp.87-121
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    • 2021
  • Since 2012, Prime Minister Shinzo Abe'sadministration began to promote women's participation and advancement in the workplace and established the Act on the Promotion of Female Participation and Career Advancement in the Workplace (the Act) in 2015. Some criticize this Act as a way to utilize women for economic development and to deal with the shrinking working population. In contrast, others point out that it is a law that can be beneficial for women. As such, this Act serves as an interesting case of a women's policy promoted by a conservative government. This paper's objective is to shed light on if and how women are substantively represented in the Diet members' statements made during the legislative debate of the bill on the Promotion of Female Participation and Career Advancement in the Workplace between 2014 and 2015. This paper asks two research questions. First, based on the mixed evaluation of the Act made in the studies about the Abe administration's women's policies, this research asks if the Diet members speak of women as resources to use for other economic and social goals or if women are substantively represented. Second, drawing insights from the literature on women's substantive representation, this research asks how Diet members speak for women. Particularly, based on the studies on conservatism and substantive representation of women, this question seeks to determine if Diet members engage in the conservative representation of women, taking women's roles as mothers and wives who provide care for children, husbands, and elders at home for granted. The results of the analysis demonstrate that the number of statements that explicitly claimed to use women was small. Second, while some Diet members of conservative political parties engaged in the conservative representation of women, there were more instances of non-conservative representation, in which a variety of types of women were represented. These findings reveal that even when the conservative government's intention to submit the bill was to utilize women rather than acting for women, Diet members could speak for various types of women and engage in the non-conservative representation of women. The findings also imply the importance of paying attention to formal and informal legislative deliberation rules to figure out how women's substantive representation can occur under a conservative government and in a legislature dominated by conservative parties.

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Fatigue Strength Assessment of A Longitudinal Hatch Coaming in a 3800 TEU Containership by ABS Dynamic Approach

  • Cui, Weicheng;Yang, Chunwen;Hu, Jiajun
    • Journal of Ship and Ocean Technology
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    • v.3 no.4
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    • pp.35-51
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    • 1999
  • Fatigue strength assessment procedures have been implemented in the ship design rules by many classification societies. However, a large variation tin the details of the different approaches exists in practically all aspects influding load history assessment, stress evaluation and fatigue strength assessment. In order to assess the influences of thesd variations on the prediction of fatigue lives. a comparative study is organized by the ISSC Committee III.2 Fatigue and Fracture. A pad detail on the top of longitudinal hatch coaming of a panamax container vessel is selected for fatigue calculation. The work described in this paper is one set of results of this comparative study in which the ABS dynamics approach is applied. Through this analysis the following conclusions can be drawn. (1) With the original ABS approach, the fatigue life of this pad detail is very low, only 2.398 years. (2) The treatment of the stillwater bending moment in the ABS approach might be a source of conservatism. If the influence of stillwater bending moment is ignored, then the fatigue life for this pad detail is 7.036 years. (3) The difference between the nominal stress approach and the hot spot stress approach for this pad detail is about 26%.

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