• 제목/요약/키워드: Revisits

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Structural robustness: A revisit

  • Andre, Joao
    • Structural Engineering and Mechanics
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    • 제76권2호
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    • pp.193-205
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    • 2020
  • The growing need for assuring efficient and sustainable investments in civil engineering structures has determined a renovated interest in the rational design of such structures from designers, clients and authorities. As a result, risk-informed decision-making methodologies are increasingly being used as a direct decision tool or as an upper-level layer from which performance-based approaches are then calibrated against. One of the most important and challenging aspects of today's structural design is to adequately handle the system-level effects, the known unknowns and the unknown unknowns. These aspects revolve around assessing and evaluating relevant damage scenarios, namely those involving unacceptable/intolerable damage levels. Hence, the importance of risk analysis of disproportionate collapse, and along with it of robustness. However, the way robustness has been used in modern design codes varies substantially, from simple provisions of prescriptive rules to complex risk analysis of the disproportionate collapse. As a result, implementing design for robustness is still very much a grey area and more so when it comes to defining means to quantify robustness. This paper revisits the most common robustness frameworks, highlighting their merits and limitations, and identifies one among them which is very promising as a way forward to solve the still open challenges.

비시장 가치평가에 대한 비판적 고찰 - 선택행동과 심리변수에 대해서 - (A Critique of Conventional Nonmarket Valuation - Attitudes and Action -)

  • 최성록
    • 자원ㆍ환경경제연구
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    • 제15권5호
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    • pp.885-919
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    • 2006
  • 본 연구는 환경 비시장가치 평가에서 일반적으로 통용되는 두 가지 '믿음'을 재조명하고 그 단점과 해결책을 고찰한다. 이 믿음은 (1) 지불의사액(WTP)이 비시장 선호도의 타당한 추정치라는 것과, (2) WTP를 설명함에 있어 외생변수(exogenous variables)의 기여도는 인정하면서도 내생변수(endogenous variables)는 무시할 수 있다는 것이다. 하지만, 심리행동학과 후생경제학의 최근 관련 문헌조사를 통해서 평가해 볼 때 두 가지 믿음으로부터의 이탈현상이 두드러지게 발견된다, 결론적으로, 이 같은 현상의 주요 원인으로 알려져 있는 응답자 이질성(heterogeneity)에 효과적으로 대처하기 위해서는 소비자의 선택행동을 설명하는 확률효용모델의 구성에 사회경제 변수와 심리태도 변수를 함께 고려하여야 한다. 특히, 측정의 번거로움을 이유로 후자가 무시될 경우 기존 문헌에서 제기된 다양한 편중(bias)에 노출됨으로써 추정치의 신뢰도가 낮아질 수 있다.

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가정간호수가 적정성 검증 및 수가체계 개선 방안 (Test on the Cost and Development on the Payment System of Home Health Care Nursing)

  • 유호신;정기선;임지영
    • 대한간호학회지
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    • 제36권3호
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    • pp.503-513
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    • 2006
  • Purpose: This study focused on analysing costs per home health care nursing visit based on home health care nursing activities in medical institutes. Method: The data was collected in three stages. First, the cost elements of home health care nursing services were collected and 31 home care nurses participated. Second, the workload and caseload of home care nursing activities were measured by the Easley-Storfjell Instrument(1997). Third, the opinions on improving the home health care nursing reimbursement system were collected by a nation-wide mailing survey from a total of 125 home care agencies. Result: The cost of home health care nursing per visit was calculated as 50,626\. This was composed of a basic visiting fee of $35,090{\\}({\fallingdotseq}355$)$ and travel fee of $15,536{\\}({\fallingdotseq}15$)$. The major problems of the home care nursing payment system were the low level of the cost per visit, no distinction between first visit and revisits, and the limitations in health insurance coverage for home health care nursing services. Conclusion: This study's results will contribute as a baseline for establishing policies for improvement of the home health care nursing cost and for applying a community-based visiting nursing service cost.

디지털 도서관에서의 도서관불안과 측정도구 분석 (Library Anxiety and library Anxiety Scale in the Digital Library Environment)

  • 권나현
    • 한국문헌정보학회지
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    • 제38권2호
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    • pp.29-47
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    • 2004
  • 본고는 도서관 정보 서비스 및 이용자교육의 중요한 연구 영역인 도서관 불안에 관한 연구를 디지털 도서관 환경 측면에서 새로이 검토하였다. 특히 본 논문은 디지털 도서관이 활성화되기 전에 개발되어 현재까지 대부분의 도서관 불안 연구에서 측정도구로 사용된 Bostick(1992)의 도서관불안척도(Library Anxiety Scale: LAS)를 분석하면서 디지털 도서관 환경에서의 변화(예: 디지털 참고 정보봉사, 원격 이용의 증가, 서지교육에서 정보이용교육으로의 질적 전환 등)를 충분히 수용하지 못하고 있는 그 도구의 한계점을 파악한 후, 이 논의를 토대로 정보이용과 관련된 불안을 측정할 수 있는 새로운 도구개발의 필요성과 방향을 제시하고자 하였다.

Financial Flexibility on Required Returns: Vector Autoregression Return Decomposition Approach

  • YIM, Sang-Giun
    • 산경연구논집
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    • 제11권5호
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    • pp.7-16
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    • 2020
  • Purpose: Prior studies empirically examine how financial flexibility is related to required returns by using realized returns and considering cash holdings as net debts, but they fail to find consistent results. Conjecturing that inappropriate proxy of required returns and aggregation of cash and debts caused the inconsistent results, this study revisits this topic by using a refined proxy of required returns and separating cash holdings from debts. Research design, data and methodology: This study uses a multivariate regression model to investigate the relationship between required returns on cash holdings and financial leverage. The required returns are estimated using the return decomposition method by vector autoregression model. Empirical tests use US stock market data from1968 to 2011. Results: Empirical results reveal that both cash holdings and leverage are positively related to required returns. The positive relation is stronger in economic downturns than in economic upturns. Conclusions: Three major findings are drawn. First, risky firms prefer large cash balance. Second, information shocks in the realized returns caused failure of prior studies to find consistent positive relationship between leverage and realized returns. Third, cash and leverage are related to required returns in the same direction; therefore, cash cannot be considered as negative debts.

The Pricing of Accruals Quality with Expected Returns: Vector Autoregression Return Decomposition Approach

  • YIM, Sang-Giun
    • 산경연구논집
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    • 제11권3호
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    • pp.7-17
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    • 2020
  • Purpose: This study reexamines the test on the pricing of accruals quality. Theory suggests that information risk is a priced risk factor. Using accruals quality as the proxy for information risk, researchers have tested the pricing of information risk. The results are inconsistent potentially because of the information shock in the realized returns that are used as the proxy for expected returns. Based on this argument, this study revisits this issue excluding information-shock-free measure of expected returns. Research design, data and methodology: This study estimates expected returns using the vector autoregression model. This method extracts information shocks more thoroughly than the methods in prior studies; therefore, the concern regarding information shock is minimized. As risk premiums are larger in recession periods than in expansion periods, recession and expansion subsamples were used to confirm the robustness of the main findings. For the pricing test, this study uses two-stage cross-sectional regression. Results: Empirical results find evidence that accruals quality is a priced risk factor. Furthermore, this study finds that the pricing of accruals quality is observed only in recession periods. Conclusions: This study supports the argument that accruals quality, as well as the pricing of information risk, is a priced risk factor.

마크 로드코의 색면추상에 표현된 색의 확장성 연구 (A Study on the Color Extendability in Mark Rothko's Color-Field Abstract)

  • 김선영
    • 한국실내디자인학회논문집
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    • 제22권1호
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    • pp.239-246
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    • 2013
  • This study is aimed at understanding the color extendibility of color-field abstract through Mark Rothko's paintings. Color extendibility is a structure applied by Mark Rothko. He simplifies it and by pursuing autonomy and immediacy of the color itself, including surface color and the front of color-field, Rothko creates value through motions in his square paintings of non-fixed shapes. Chapter 2 revisits the meaning of color in abstract expressionism and explains the principle of color-field by applying the concept of ergon and parergon. In chapter 3, the principle, processes, methods, techniques of expression were studied as a basis to understand color extendibility and color-field abstract. In chapter 4, the works of Mark Rothko were analyzed based on his multiform paintings(1946-1948), number and untitled(1949-1957), and black paintings(1958-1970) in order to identify, in the final chapter, the features of color extendibility in Rothko's works. According to the above research, the thesis successfully concludes that the artist's reconstruction of reality and readjustment of transcendent reality are reproduced via color extendibility, the movement of color-field.

Flight Dynamics and Navigation for Planetary Missions in Korea: Past Efforts, Recent Status, and Future Preparations

  • Song, Young-Joo;Lee, Donghun;Bae, Jonghee;Kim, Young-Rok;Choi, Su-Jin
    • Journal of Astronomy and Space Sciences
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    • 제35권3호
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    • pp.119-131
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    • 2018
  • In spite of a short history of only 30 years in space development, Korea has achieved outstanding space development capabilities, and became the $11^{th}$ member of the "Space Club" in 2013 by launching its own satellites with its own launch vehicle from a local space center. With the successful development and operation of more than 10 earth-orbiting satellites since 1999, Korea is now rapidly expanding its own aspirations to outer space exploration. Unlike earth-orbiting missions, planetary missions are more demanding of well-rounded technological capabilities, specifically trajectory design, analysis, and navigation. Because of the importance of relevant technologies, the Korean astronautical society devoted significant efforts to secure these basic technologies from the early 2000s. This paper revisits the numerous efforts conducted to date, specifically regarding flight dynamics and navigation technology, to prepare for future upcoming planetary missions in Korea. However, sustained efforts are still required to realize such challenging planetary missions, and efforts to date will significantly advance the relevant Korean technological capabilities.

Dictionary Attacks against Password-Based Authenticated Three-Party Key Exchange Protocols

  • Nam, Junghyun;Choo, Kim-Kwang Raymond;Kim, Moonseong;Paik, Juryon;Won, Dongho
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제7권12호
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    • pp.3244-3260
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    • 2013
  • A three-party password-based authenticated key exchange (PAKE) protocol allows two clients registered with a trusted server to generate a common cryptographic key from their individual passwords shared only with the server. A key requirement for three-party PAKE protocols is to prevent an adversary from mounting a dictionary attack. This requirement must be met even when the adversary is a malicious (registered) client who can set up normal protocol sessions with other clients. This work revisits three existing three-party PAKE protocols, namely, Guo et al.'s (2008) protocol, Huang's (2009) protocol, and Lee and Hwang's (2010) protocol, and demonstrates that these protocols are not secure against offline and/or (undetectable) online dictionary attacks in the presence of a malicious client. The offline dictionary attack we present against Guo et al.'s protocol also applies to other similar protocols including Lee and Hwang's protocol. We conclude with some suggestions on how to design a three-party PAKE protocol that is resistant against dictionary attacks.

구조방정식 모형을 이용한 치과 임플란트 환자의 만족과 재이용 의사에 미치는 영향요인 분석 (Associated factors which influence satisfaction of dental implant patients and intention to revisit using structural equation model)

  • 조민숙;유성진;양동현
    • 한국치위생학회지
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    • 제13권2호
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    • pp.221-230
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    • 2013
  • Objectives : This study is to confirm the influencing factors on patients satisfaction and intention to revisit the implant service clinic by structural equation model. Methods : We surveyed 250 implant patients visiting 6 dental clnics(hospitals) in Busan, Changwon, Gimhae city and questionnaire was for four weeks in July 2012, a total 209 patients filled out the questionnaires within July and the complete data were analyzed. we were used structural equation model for analysis to confirm influencing factors on implant patients' satisfaction and intention to revisits. Results : This study finds that factors influencing on implant patients' satisfaction and intention to revisit are reasonable medical fee, medical skill treatment of dentist, dental hygienist and other support staff, administrative procedure, and there existed between influencing factors and the patient's treatment satisfaction as well as intention to revisit. In order to satisfy the implant patients, dentist and hygienists should try to provide high quality of treatment and dental services. Conclusions : The results of this study provide managerially important messages to the managers of dental clinics in order to develope management strategies for new customers.