• 한국전산구조공학회논문집
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• 제23권6호
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• pp.703-714
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• 2010

This paper proposes an approach for staged finite element modeling with coupled seepage and stress analysis. The stage modeling is based on the predefined inter-relationship between the base model and the unit stage models. A unit stage constitutes a complete finite element model, of which the geometries and attributes are subject to changes from stage to stage. The seepage analysis precedes the mechanical stress analysis at every stage. Division of the wet and dry zone and the pore pressures are evaluated from the seepage analysis and used in determining input data for the stress analysis. The results of the stress analysis may also be associated with the pore water pressures. For consolidation analysis, the pore pressure and the displacement variables are mixed in a coupled matrix equation. The time marching solution produces the dissipation of excess pore pressure and variation of stresses with passage of time. For undrained analysis, the excess pore pressures are computed from the stress increment due to loading applied in the unit stage and are used in revising the hydraulic head. The solution results of a unit stage are inherited and accumulated to the subsequent stages through the relationship of the base model and the individual unit stages. Implementation of the proposed approach is outlined on the basis of the core procedures, and numerical examples are presented for demonstration of its application.

• Nuclear Engineering and Technology
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• 제47권7호
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• pp.849-858
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• 2015

This study set the pyroprocess facility at an engineering scale as a cost object, and presented the cost consumed during the unit processes of the pyroprocess. For the cost calculation, the activity based costing (ABC) method was used instead of the engineering cost estimation method, which calculates the cost based on the conceptual design of the pyroprocess facility. The calculation results demonstrate that the pyroprocess facility's unit process cost is $194/kgHM for pretreatment, $298/kgHM for electrochemical reduction, $226/kgHM for electrorefining, and $299/kgHM for electrowinning. An analysis demonstrated that the share of each unit process cost among the total pyroprocess cost is as follows: 19% for pretreatment, 29% for electrochemical reduction, 22% for electrorefining, and 30% for electrowinning. The total unit cost of the pyroprocess was calculated at $1,017/kgHM. In the end, electrochemical reduction and the electrowinning process took up most of the cost, and the individual costs for these two processes was found to be similar. This is because significant raw material cost is required for the electrochemical reduction process, which uses platinum as an anode electrode. In addition, significant raw material costs are required, such as for $Li_3PO_4$, which is used a lot during the salt purification process.

• 대한건축학회연합논문집
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• 제20권6호
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• pp.9-16
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• 2018

The purpose of this research was influenced by the historical background of Japanese modern architecture by the circulation of Kuma Kengo's architectural works and he wanted to look at the values and directions he was pursuing and how they were expressed in his works. The results of the review are summarized as follows. First, metabolism was developed as a reaction of modernism in modern architecture, focusing on growth through infinite reproduction by looking at architecture and cities as organisms and by using unit space as cells. Kuma Kengo, on the other hand, argues that focusing on the possibility of decimation of unit members by sequencing the elements that make up the space smaller than the unit space is closer to an ecological architecture. Second, what Kuma Kengo says is "erase the architecture" that is naturally related to the environment and disappears when its use is exhausted. His argument is expressed in individual architectural works through 'visual erase', 'particle painting of materials' and 'independence through dependency.' Through this, Kuma Kengo's ecological architectural languages were influenced by the ecological causes of metabolism, but they differed from the perspective of seeing architectural circulation as an organism. If metabolism was intended to realize circulation with growth potential based on the module of unit space, Kuma Kengo sought to implement circulation with the extinction of the unit members of space.

• Pediatric Infection and Vaccine
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• 제18권1호
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• pp.15-22
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• 2011

Invasive Candida infections (ICI) have become the third most common cause of late-onset infection among premature infants in the neonatal intensive care unit (NICU). Risk factors include birth weight less than 1,000 g, exposure to more than two antimicrobials, third generation cephalosporin exposure, parenteral nutrition including lipid emulsion, central venous catheter, and abdominal surgery. Candida colonization of the skin and gastrointestinal tract is an important first step in the pathogenesis of invasive disease. Strict infection control measures against the infection should be done in the NICU. The following practices are likely to contribute to reducing the rate of ICI: (1) restriction of broad-spectrum antibiotics, antacids and steroid; (2) introduction of early feeding and promoting breast milk. Fluconazole prophylaxis may be an effective control measure to prevent Candida colonization and infections in individual units with high incidence of fungal infection. In addition, there is a need of further data including the development of resistant strains and the effect on long-term neurodevelopmental outcomes of infants exposed to drugs before the initiation of routine application of antifungal prophylaxis in the NICU.

• 자연과학논문집
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• 제5권2호
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• pp.63-73
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• 1992

There are many methods of obtaining butadiene described in the literature. In the america it is produced largely from petroleum gases, i.e., by catalytic dehydrogenation of butene of butene-butane mixtures. Butadiene can be recovered from the $C_4$ residue of an olefin plant by distilling off a fraction containing most of the butadiene, catalytically hydrogenating the higher acetylenes to olefins and separating the product from other olefins and isobutane by extraction. Also it can be obtained by cracking naphtha and light oil. Among the individual dienes of commercial importance, 1, 3-butadiene is of first importance. It is used primarily for the production of polymers.In the present paper, it was investigated for a effect of the formation and the growth inhibition of popped corn polymer in butadiene extraction unit. As a result of study, inhibitors, $NaNO_2$ and TBC were good effective for inhibition of the formation and growth in popcorn polymer. The rational formula of popcorn polymer obtained was $(C_4H_6)_x$.

• 융합보안논문지
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• 제6권4호
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• pp.1-9
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• 2006

역할 기반 접근제어 모델은 접근 권한이 역할(role)에 부여되고 사용자는 적절한 역할에 소속됨으로서 역할의 수행에 필요한 최소 자원만을 접근할 수 있도록 한다. 본 논문에서는 RBAC의 중요한 논점 중에 하나인 위임의 문제를 권한 위임, 관리, 감독에 있어 실제 기업에서 이루어지는 사용자 수준에서 기능단위로 적용하는 새로운 모델을 제안한다. 위임을 기능단위로 하면 역할을 직접 위임하는 기존의 방식보다 위임으로 인한 권한 적용 오류를 최소화된다. 또한 위임에 따른 보안문제를 감독하기 위해 승인부분을 추가하였다.

• 성인간호학회지
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• 제27권5호
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• pp.548-558
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• 2015

Purpose: The purpose of this study was to explore the experience of workplace violence among intensive care unit nurses. Methods: The participants of this research were twelve registered nurses who work in the intensive care units (ICU) at the hospitals in Seoul and Gyunggido. Data were collected by individual in-depth interviews and analyzed using the phenomenological methodology by Colaizzi. Results: From significant statements, five theme clusters emerged as follow; 1) vulnerable young women to violence, 2) my own reflection was bruised and exhausted, 3) a hopeless everyday, 4) seeking a solution in relation, 5) establishing one's status as a professional nurse. Conclusion: This study provides a profound understanding on the experiences of workplace violence among ICU nurses. The hospitals are suggested to provide a safe environment by developing programs and policies to prevent and cope with hospital workplace violence for ICU nurses.

• 품질경영학회지
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• 제28권2호
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• pp.123-134
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• 2000

In the survey, it is very hard to get the complete response. Because the respondents tend to refuse to the questionnaire with something like incomes of the individual or may not be at home in the survey time. These nonresponses are classified into two groups as the item nonresponse and the unit nonresponse. When the nonresponse happen to the special item of the questionnaire, it is caned item nonresponse. On the other hand the unit nonresponse occurs to the totally missing in questionnaire. In this paper, we only consider to the unit nonresponse situation. We propose that the optimal estimator which is minimized the variance of the estimator under a fixed cost function for the survey and response.

• East Asian Economic Review
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• 제20권4호
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• pp.493-517
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• 2016

This paper examines the persistent properties of 12 sectoral relative prices between Korea and Japan obtained following the Classification of Individual Consumption according to Purpose (COICOP) over the period of 1985-2016. Applying a new econometric method developed by Pesaran which controls for the cross-section dependence in a panel, we are not able to reject the hypothesis that the sectoral real exchange rates contain a common stochastic trend. On the other hand, the well-known panel unit root tests such as the IPS and LLC tests widely used by previous studies strongly reject the unit root hypothesis. Since the error term of the regression for our panel exhibits significant cross-section dependence, these opposite results justify that the use of the new econometric method is appropriate.

• 한국안전학회지
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• 제35권1호
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• pp.97-106
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• 2020

The objective of this paper is to suggest a new quantification method for multi-unit probabilistic safety assessment (PSA) that removes the overestimation error caused by the existing delete-term approximation (DTA) based quantification method. So far, for the actual plant PSA model quantification, a fault tree with negates have been solved by the DTA method. It is well known that the DTA method induces overestimated core damage frequency (CDF) of nuclear power plant (NPP). If a PSA fault tree has negates and non-rare events, the overestimation in CDF drastically increases. Since multi-unit seismic PSA model has plant level negates and many non-rare events in the fault tree, it should be very carefully quantified in order to avoid CDF overestimation. Multi-unit PSA fault tree has normal gates and negates that represent each NPP status. The NPP status means core damage or non-core damage state of individual NPPs. The non-core damage state of a NPP is modeled in the fault tree by using a negate (a NOT gate). Authors reviewed and compared (1) quantification methods that generate exact or approximate Boolean solutions from a fault tree, (2) DTA method generating approximate Boolean solution by solving negates in a fault tree, and (3) probability calculation methods from the Boolean solutions generated by exact quantification methods or DTA method. Based on the review and comparison, a new intersection removal by probability (IRBP) method is suggested in this study for the multi-unit PSA. If the IRBP method is adopted, multi-unit PSA fault tree can be quantified without the overestimation error that is caused by the direct application of DTA method. That is, the extremely overestimated CDF can be avoided and accurate CDF can be calculated by using the IRBP method. The accuracy of the IRBP method was validated by simple multi-unit PSA models. The necessity of the IRBP method was demonstrated by the actual plant multi-unit seismic PSA models.