• Coupled systems mechanics
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• 제3권2호
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• pp.195-211
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• 2014

When strong seismic forces act on reinforced concrete structures, their beam-column connections are very susceptible to damage during the earthquake event. The aim of this numerical work is to evaluate the influence of the internal steel reinforcement array on the nonlinear response of a RC beam-column connection when it is subjected to strong cyclic loading -as a seismic load. For this, two specimens (extracted from an experimental test of 12 RC beam-column connections reported in literature) were modeled in the Finite Element code FEAP considering different stirrup's arrays. In order to evaluate the nonlinear response of the RC beam-column connection, the 2D model takes into account the nonlinear thermodynamic behavior of each component: for concrete, a damage model is used; for steel reinforcement, it is adopted a classical plasticity model; in the case of the steel-concrete bonding, this one is considered perfect without degradation. At the end, we show a comparison between the experimental test's responses and the numerical results, which includes the distribution of shear stresses and damage inside the concrete core of the beam-column connection; in the other hand, the effects on the connection of a low and high state of confinement are analyzed for all cases.

• Nuclear Engineering and Technology
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• 제30권6호
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• pp.531-540
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• 1998

The DYLAM-3 code which overcomes the limitation of event tree/fault tree was applied to LOOP (Loss of Off-site Power) in the mid-loop operation employing HEPs (Human Error Probabilities) supplied by the ASEP (Accident Sequence Evaluation Program) and the SEPLOT (Systematic Evaluation Procedure for Low power/shutdown Operation Task) procedure in this study. Thus the time history of core uncovery frequency during the mid-loop operation was obtained. The sensitivity calculations in the operator's actions to prevent core uncovery under LOOP in the mid-loop operation were carried out. The analysis using the time dependent HEP was performed on the primary feed & bleed which has the most significant effect on core uncovery frequency. As the result, the increment of frequency is shown after 200 minutes duration of simulation conditions. This signifies the possibility of increment in risk after 200 minutes. The primary feed & bleed showed the greatest impact on core uncovery frequency and the recovery of the SCS (Shutdown Cooling System) showed the least impact. Therefore the efforts should be taken on the primary feed & bleed to reduce the core uncovery frequency in the mid-loop operation. And the capability of DYLAM-3 in applying to the time dependent concerns could be demonstrated.

• 한국추진공학회지
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• 제22권4호
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• pp.91-98
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• 2018

본 연구에서는 중첩된 두 비행물체에서 단분리 시 일어나는 주위 유동장 분석에 초점을 맞춰 해석을 수행하였다. 수치 해석을 위하여 정지된 비행체에서 분리되는 실린더 형태의 부스터를 중첩격자를 이용하여 모델링 하였으며 상용해석코드인 $CFD-FASTRAN^{TM}$을 사용하여 계산하였다. 실제 현상을 모사하기 위해서는 부스터에 대한 스프링 반발력, 중력, 상대 속도 등의 고려가 필수적인 요소였다. 연구결과, 부스터의 분리 시간은 비행 마하수와 받음각이 증가함에 따라 감소하는 것을 확인할 수 있었으며, 현재까지의 결과를 종합하여 볼 때 본 연구에서 수행한 모델링과 경계조건 등의 구성이 비행시험의 안전한 부스터 분리와 이후 시퀀스를 예측하는데 많은 도움을 줄 것으로 판단된다.

• Computers and Concrete
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• 제7권2호
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• pp.103-118
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• 2010

Penetration of a fragment-like projectile into Fiber Reinforced Concrete (FRC) was simulated using finite element (FE) and particle formulations. Extreme deformations and failure of the material during the penetration event were modeled with multiple approaches to evaluate how well each represented the actual physics of the penetration process and compared to experimental data. A Fragment Simulating Projectile(FSP) normally impacting a flat, square plate of FRC was modeled using two target thicknesses to examine the different levels of damage. The thinner plate was perforated by the FSP, while the thicker plate captured the FSP and only allowed penetration part way through the thickness. Full three dimensional simulations were performed, so the capability was present for non-symmetric FRC behavior and possible projectile rotation in all directions. These calculations assessed the ability of the finite element and particle formulations to calculate penetration response while assessing criteria necessary to perform the computations. The numerical code EPIC contains the element and particle formulations, as well as the explicit methodology and constitutive models, needed to perform these simulations.

• 영어영문학
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• 제57권4호
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• pp.675-693
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• 2011

In its restricted sense, 'sound poetry' refers to the poetic performance that rejects words and verbal meaning and instead foregrounds the aural materiality of poetry. Behind this seeking for materiality lies a quest for a 'language of presence,' which operates through a denial of signification toward an ideal of the Adamic tongue, a purely emotional and universal language. In the same light, it is argued that sound poetry is a unique and unrepeatable event devoid of meaning due to its directness to the body allowing no intervention of intellectual and semiotic process. But language may involve perceptual meaning as well as verbal or conceptual meaning ascribed to words. This implies that even though devoid of conceptual meaning by means of using grammatically non-articulated sounds, sound poetry cannot but have meaning whose articulation is differently, i.e., iconically made about the aural features of the sounds. Perceptual meaning is unavoidable because everything we are conscious of is a reduced form, a repeatable pattern that works as a sign. 'Language of presence' is then actually impossible, and therefore sound poetry should be seen rather as a fest of diverse perceptual meanings.

• Nuclear Engineering and Technology
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• 제53권2호
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• pp.484-497
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• 2021

This paper proposes an extended time uncertainty analysis approach in Level 2 human reliability analysis (HRA) considering severe accident management (SAM) strategies. The method is a time-based model that classifies two time distribution functions-time required and time available-to calculate human failure probabilities from delayed action when implementing SAM strategies. The time required function can be obtained by the combination of four time factors: 1) time for diagnosis and decision by the technical support center (TSC) for a given strategy, 2) time for strategy implementation mainly by the local emergency response organization (ERO), 3) time to verify the effectiveness of the strategy and 4) time for portable equipment transport and installation. This function can vary depending on the given scenario and includes a summation of lognormal distributions and a choice regarding shifting the distribution. The time available function can be obtained via thermal-hydraulic code simulation (MAAP 5.03). The proposed approach was applied to assess SAM strategies that use portable equipment and safety depressurization system valves in a total loss of component cooling water event that could cause reactor vessel failure. The results from the proposed method are more realistic (i.e., not conservative) than other existing methods in evaluating SAM strategies involving the use of portable equipment.

• 시스템엔지니어링학술지
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• 제19권2호
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• pp.32-45
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• 2023

Implementing Severe Accident Management (SAM) strategies is crucial for enhancing a nuclear power plant's resilience and safety against severe accidents conditions represented in the analysis of Station Blackout (SBO) event. Among these critical approaches, the In-Vessel Retention (IVR) through External Reactor Vessel Cooling (IVR-ERVC) strategy plays a key role in preventing vessel failure. This work is designed to evaluate the efficacy of the IVR strategy for a high-power density reactor APR1400. The APR1400's plant is represented and simulated under steady-state and transient conditions for a station blackout (SBO) accident scenario using the computer code, ASYST. The APR1400's thermal-hydraulic response is analyzed to assess its performance as it progresses toward a severe accident scenario during an extended SBO. The effectiveness of emergency operating procedures (EOPs) and severe accident management guidelines (SAMGs) are systematically examined to assess their ability to mitigate the accident. A group of associated key phenomena selected based on Phenomenon Identification and Ranking Tables (PIRT) and uncertain parameters are identified accordingly and then propagated within DAKOTA Uncertainty Quantification (UQ) framework until a statistically representative sample is obtained and hence determine the uncertainty bands of key system parameters. The Systems Engineering methodology is applied to direct the progression of work, ensuring systematic and efficient execution.

• 한국중재학회지:중재연구
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• 제8권1호
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• pp.293-322
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• 1998

General Administrative Procedures of the Preshipment Inspection 1. Initial notification Preshipment Inspection is initiated by Agency when it receives notice either from the importing country, or the seller, that an export needs to be imspected 1.1 Notice from the importing country 1.2 Notice from the seller 2. Preliminary price verification After receipt of initial notification, Agency undertakes, Where possible, a preliminary price verification, based upon the Inspection Order and other contractual documents received. 3. Customs classification When required by the Government of the importing country. Agency forms an opinion of the Customs Classification Code based upon the Customs Tariff Book and Rules of Classification of the country of importation. The Customs Classification Code determines the tariff rate on the basis of which the importer will be required to pay import duties. 4. Import eligibility 5. Arrangements for physical inspection 5.1 Inspection request from seller 5.2 Place of inspection 5.3 Date of inspection 5.4 Physical inspection procedures 6. Physical inspection results When the physical inspection is completed, the inspector submits his report to the Agency office and the result of inspection will be communicated to the seller and, where applicable, the place of inspection. The result will state: satisfactory or conditional of unsatisfactory. The seller is welcome to present his views in writting to Agency in the event there is any query regarding the issuance of a conditional of unsatisfactory inspection result. 6.1 Satisfactory 6.2 Conditional 6.3 Unsatisfactory 7. Shipment of the goods The seller is advised to check with Agency prior to shipment if the physical inspection result has not been received or there are any doubts concerning whether a Clean Report of Findings will be issued. 8. Final price verification and classification Based on the results of physical inspection and appropriate final documents, Agency finalises the price verification and the Agency opinion of Customs classification code. When the preliminary price verification has not resulted in any unresolved questions and the inspection result and other documents received are consistent with the preliminary documentation, Agency will not normally require any additional information. The main exception would be if the terms of sale require reference to prices at the date of shipment. 9. The Report of Findings 9.1 Types of Reports of Findings - Clean Reports of Findings(CRF) The Agency will issue a Clean Reports of Findings(CRF), or equivalent document, normally within two working days after receipt of the necessary correct final documents and a satisfactory result in all aspects of the inspection. - Discrepancy Report.

• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제1권1호
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• pp.1-6
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• 2012

템플릿 기반 웹 애플리케이션(TWA)은 웹 페이지들의 공통부분을 단일 코드 파일(템플릿)로, 각 페이지에 특화된 부분은 별도의 파일로 관리한다. HTTP 요청이 발생하면 이 두 종류 파일을 동적으로 조합하여 웹 페이지를 생성한다. 이를 통해 사용자에게 일관된 UI을 제공하며 코드 중복을 제거해 유지보수성을 향상시킨다. 그러나 TWA는 사용자의 요청 시 현재 페이지에서 바뀌어야 할 부분이 일부지만 페이지 전환이 이루어져 갱신이 불필요한 데이터까지 전송되고 처리되는 문제가 있다. 본 논문은 Java 기반 TWA를 대상으로 이 문제를 해결한다. 제안 기법은 페이지 전환을 제거하기 위해 HTML에 있는 하이퍼링크를 AJAX를 이용하는 JavaScript 이벤트 핸들러로 변환한다. 또한 갱신에 필요한 데이터만 반환하기 위해 JSP, Servlet 코드에서 템플릿 전송 코드를 제거한다. 따라서 이 기법은 페이지 전환으로 발생하는 네트워크와 CPU 부하를 감소시키며, 비동기적인 페이지 업데이트로 사용자의 체감 성능을 향상시킨다. 성능 검증을 위해 전형적인 TWA를 대상으로 이 기법을 적용하였다. 성능 측정 결과 기존 TWA보다 응답시간을 최대 87% 개선하였다.

• 한국방사선학회논문지
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• 제12권6호
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• pp.719-725
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• 2018

미국 9.11 사고 이후 테러는 과거에 비하여 다중이용시설 공격을 통한 불특정 다수의 공격이 증가하고 있다. 연이은 런던 폭탄테러, 파키스탄의 자폭 등은 사람들의 공포심 및 사회적 불안감을 증가시켰다. 최근 국내에서 다양한 국제행사가 개최되고 있어, 방사능테러 위협에 대비한 방사성물질의 국가 안보 의식이 증대되고 있다. 본 논문에서는 HotSpot Code를 사용하여 서로 상이한 기상조건에 따른 결과를 비교하였다. 국내에서 발생 가능한 테러 시나리오 작성 후, RDD(Radiological Dispersal Device) 및 더티밤에 사용될 가능성이 높은 선원을 조사하였다. 기상조건은 Pasquill-Gifford 안정도 등급에 따라 가장 안정된 조건의 F, 가장 불안정한 조건의 A를 선택하여 비교하였다. 시뮬레이션을 통한 A, F 등급 결괏값은 방사선학적 영향에 의해 시민들이 급성 영향으로 사망하는 경우는 없다고 판단하였다. 또한, 풍속 및 기상 안정도에 따라 방사능의 도달 정도가 서로 다르며, 기상 조건에 따라 방사능 희석정도가 서로 다름을 확인할 수 있다. 분석결과는 방사능테러 발생 시 초동 대응에 활용할 수 있을 것으로 예상된다.