• Nuclear Engineering and Technology
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• v.44 no.2
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• pp.177-198
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• 2012

This paper reviews the fast reactor physics and computational methods. The basic reactor physics specific to fast spectrum reactors are briefly reviewed, focused on fissile material breeding and actinide burning. Design implications and reactivity feedback characteristics are compared between breeder and burner reactors. Some discussions are given to the distinct nuclear characteristics of fast reactors that make the assumptions employed in traditional LWR analysis methods not applicable. Reactor physics analysis codes used for the modeling of fast reactor designs in the U.S. are reviewed. This review covers cross-section generation capabilities, whole-core deterministic (diffusion and transport) and Monte Carlo calculation tools, depletion and fuel cycle analysis codes, perturbation theory codes for reactivity coefficient calculation and cross section sensitivity analysis, and uncertainty analysis codes.

• Wind and Structures
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• v.19 no.5
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• pp.467-480
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• 2014

The estimation of wind speed values used in codes and standards is an integral part of the wind load evaluation process. In a number of codes and standards, wind speeds outside of tropical cyclone prone regions are estimated using a single probability distribution developed from observed wind speed data, with no distinction made between the types of causal wind hazard (e.g., thunderstorm). Non-tropical cyclone wind hazards (i.e., thunderstorm, non-thunderstorm) have been shown to possess different probability distributions and estimation of non-tropical cyclone wind speeds based on a single probability distribution has been shown to underestimate wind speeds. Current treatment of non-tropical cyclone wind hazards in worldwide codes and standards is touched upon in this work. Meteorological data is available at a considerable number of United States (U.S.) stations that have information on wind speed as well as the type of causal wind hazard. In this paper, probability distributions are fit to distinct storm types (i.e., thunderstorm and non-thunderstorm) and the results of these distributions are compared to fitting a single probability distribution to all data regardless of storm type (i.e., co-mingled). Distributions fitted to data separated by storm type and co-mingled data will also be compared to a derived (i.e., "mixed") probability distribution considering multiple storm types independently. This paper will analyze two extreme value distributions (e.g., Gumbel, generalized Pareto). It is shown that mixed probability distribution, on average, is a more conservative measure for extreme wind speed estimation. Using a mixed distribution is especially conservative in situations where a given wind speed value for either storm type has a similar probability of occurrence, and/or when a less frequent storm type produces the highest overall wind speeds. U.S. areas prone to multiple non-tropical cyclone wind hazards are identified.

• Nuclear Engineering and Technology
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• v.43 no.6
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• pp.509-522
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• 2011

FRAPCON-3.4a and FRAPTRAN 1.4 are the most recent versions of the U.S. Nuclear Regulatory Commission (NRC) steady-state and transient fuel performance codes, respectively. These codes have been assessed against separate effects data and integral assessment data and have been determined to provide a best estimate calculation of fuel performance. Recent updates included in FRAPCON-3.4a include updated material properties models, models for new fuel and cladding types, cladding finite element analysis capability, and capability to perform uncertainty analyses and calculate upper tolerance limits for important outputs. Recent updates included in FRAPTRAN 1.4 include: material properties models that are consistent with FRAPCON-3.4a, cladding failure models that are applicable for loss-of coolant-accident and reactivity initiated accident modeling, and updated heat transfer models. This paper briefly describes these code updates and data assessments, highlighting the particularly important improvements and data assessments. This paper also discusses areas of improvements that will be addressed in upcoming code versions.

• Steel and Composite Structures
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• v.44 no.6
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• pp.845-865
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• 2022

In this study, the performance of shear deficient reinforced concrete (RC) beams with rectangular cross-sections, which were externally bonded reinforced (EBR) with high strength CFRP and GFRP strips composite along shear spans, has been experimentally and analytically investigated under vertical load. In the study, the minimum CFRP and GFRP strips width over spacing were considered. The shear beam with turned end to a bending beam was investigated by applying different composite strips. Therefore various arising in each of strength, ductility, rigidity, and energy dissipation capacity were obtained. A total of 12 small-scaled experimental programs have been performed. Beam dimensions have been taken as 100×150×1000 mm. Four beams have been tested as unstrengthened samples. This paper focuses on the effect of minimum CFRP and GFRP strip width on behaviours of RC beams shear-strengthened with full-wrapping, U-wrapping, and U-wrapping+longitudinal bonding strips. Strengthened beams showed significant increments for flexural ductility, energy dissipation, and inelastic performance. The full wrapping strips applied against shear failure have increased the load-carrying capacity of samples 53%-63% interval rate. Although full wrapping is the best strengthening choice, the U-wrapping and U-wrapping+longitudinal strips of both CFRP and GFRP bonding increased the shear capacity by 53%~75% compared to the S2 sample. In terms of ductility, the best result has been obtained by the type of strengthening where the S5 beam was completely GFRP wrapped. The experimental results were also compared with the analytically given by ACI440.2R-17, TBEC-2019 and FIB-2001. Especially in U-wrapped beams, the estimation of FIB was determined to be 81%. The estimates of the other codes are far from meeting the experimental results; therefore, essential improvements should be applied to the codes, especially regarding CFRP and GFRP deformation and approaches for longitudinal strip connections. According to the test results, it is suggested that GFRP, which is at least as effective but cheaper than CFRP, may be preferred for strengthening applications.

• Bulletin of the Korean Mathematical Society
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• v.55 no.2
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• pp.633-647
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• 2018

We compare the Lee and homogenous weights over the chain ring $S_{q,m}={\mathbb{F}}_q[u]/(u^m)$ by computing the minimum distance of random codes for small values of n, q, m.

• The Journal of the Acoustical Society of Korea
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• v.12 no.1
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• pp.20-26
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• 1993

본 논문은 Reed-Solomon부호의 복호가능어 가중치 분포에 대한 명시적 식과 근사식을 구하여 이를 복호기 오류확률 PE(u)에 적용하고, 복호기 오류확률의 상한식을 구하고 분석하였다. t+1개 이상의 오류가 발생했을 때 복호기 오류확률의 추정치 Q와 Q'를 개선하여 식 Q를 제안하고, 컴퓨터 시뮬레이션을 수행한 결과 가중치 u가 커질 때 복호기 오류확률은 추정치 Q와 Q'에는 접근하였으나, 본 논문에서 제안한 Q와는 일치됨을 확인하였다. 그리고, 가중치 u가 부호의 길이 n에 접근할 때, 복호가능어의 명시적 식 Du와 근사식 Du'가 서로 일치하고, 복호기 오류확률 Pe(u)와 근사오류확률 Pe(u')가 일치함을 보였다. 또하 t+1개 이상의 오류가 발생했을 때 복호기 오류확률은 1/t!보다 작으며, 가중치분포 Au에 Vn(t)를 곱한 결과는 근사복호가능어 Du'와 일치함도 확인하였다.

• Journal of Korea Technology Innovation Society
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• v.16 no.2
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• pp.444-475
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• 2013

This study explores the trajectories of institutionalization for technology transfer both in the U.S. and Korea, particularly focusing on two universities: Korea Advanced Institute of Science and Technology (KAIST), and the University of California (UC). By comparing the diverging paths of the two universities in setting up institutions, this paper examines the limits of and lessons for technology transfer policies both to Korean government and universities in Korea. The University of California was involved in designing rules and codes, on one hand, to stimulate its members' engagements with technology transfer activity and, on the other hand, to keep its academic integrity since, no later than, the 1960s. The efforts and consequences range from its rules of patenting system to its codes of conducts. Through making rules formal and resolving conflicts on technology transfer activity, the U.S., and the University of California have decreased uncertainties for its members' engagements with industries. By contrast, KAIST has not built up such range of rules or codes due to its shorter experience and its constraining legal contexts. Korea introduced the legal format of the US Bayh-Dole Act in 2002, and its central government has led the initiatives for technology transfer, not allowing much latitude for its universities. This study implies a set of policy recommendations to the Korean government and KAIST: to build entrepreneurial universities, the government should give greater latitude to universities, so universities should be more rigorously engaged in developing their own rules and routines; the government, rather, should focus on providing bridging R&D funds like the Small Business Innovation Research (SBIR), so researchers could draw on resources to move their basic research into next phases; KAIST would be better to promote its members to engage with industries, and introduce conduct codes that allow its academics to engage in industrial activity, rather than building up its commercialization facilities.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.465-468
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• 2008

In this paper, ABAQUS, one of the implicit finite element codes, is used to analyze the U-channel Draw benchmark problem of NUMISHEET 2005. Forming and springback stages have been done consecutively to compare their results with the experimental ones. The main measures for comparing are the side wall curl and angle. The result by numerical analysis are shown generally to be correspondent with the experimental results that the max. error is confined under about 10%.

• ETRI Journal
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• v.30 no.6
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• pp.807-817
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• 2008

We present a low-density parity-check (LDPC)-based, threaded layered space-time-frequency system with emphasis on the iterative receiver design. First, the unbiased minimum mean-squared-error iterative-tree-search (U-MMSE-ITS) detector, which is known to be one of the most efficient multi-input multi-output (MIMO) detectors available, is improved by augmentation of the partial-length paths and by the addition of one-bit complement sequences. Compared with the U-MMSE-ITS detector, the improved detector provides better detection performance with lower complexity. Furthermore, the improved detector is robust to arbitrary MIMO channels and to any antenna configurations. Second, based on the structure of the iterative receiver, we present a low-complexity belief-propagation (BP) decoding algorithm for LDPC-codes. This BP decoder not only has low computing complexity but also converges very fast (5 iterations is sufficient). With the efficient receiver employing the improved detector and the low-complexity BP decoder, the proposed system is a promising solution to high-data-rate transmission over selective-fading channels.

• Korean Security Journal
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• no.6
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• pp.1-46
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• 2003

During the ancient times, there was no separative judicial system and administrative , legislative and judiciary functions were ultimately concentrated in the all-powerful monarch. And the three states developed state organization , adopting hieratical structures and placing at the pinnacle . State Codes were promulgated to initiate a legal system to rule the people, these codes instituted under influence of China codes. The people tradition sees crime control as the preservation of the authority of hereditary rulers. In the period of the Koryeo dynasty, government accepted a serious of detailed penal code from Tang dynasty . Legal response to crime stressed preservation of the dynasty rather than making citizen behave according to certain rules. In the period of Early Joseon , the compilation of Grand Code for state administration was initiated, the Kyeongkuk Taejeon ,became comer stone of the dynastic administration and provided the monarchial system with a sort of constitutional law in written form. This national code was in portant means of criminal policy at that time, Late Joseon , the impact of Western culture entering through China gave further impetus to pragmatic studies which called for socio-economic reforms and readjustment. Approach to criminal justice policy emphasized more equitable operation of the criminal justice system ,rehabilitation and crime control. Korea-Japanese Treaty concluded on 22 August ,1910 and proclaim a week later ,Japan gave the coup de grace to the Korea Empire and changed the office of the Resident - General into the Government - General . Thus korean criminal policy were lost during a dark ages ,which lasted for 36 years after fall of Joseon Dynasty (the colnial period,1910${\sim}$1945). After 1945 Korea's liberation from Japanese colonial rule, the occupation of devided Korea by the United States and Soviet Union frustrated the efforts of Koreans to establish an independent government, and the transplantation of two conflicting political ideologies to south and the north of the 38th parallel further intensified the national split. U.S. military government office occupied the south of the 38 the parallel and placed emphasis on democracy of criminal policy. ln 1948, the U.S. military government handed over to the ROK government its administrative authority.