• Nuclear Engineering and Technology
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• 제38권5호
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• pp.411-416
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• 2006

The Advanced Test Reactor (ATR), at the Idaho National Laboratory (INL), is one of the world's premier test reactors for providing the capability for studying the effects of intense neutron and gamma radiation on reactor materials and fuels. The physical configuration of the ATR, a 4-leaf clover shape, allows the reactor to be operated at different power levels in the comer 'lobes' to allow for different testing conditions for multiple simultaneous experiments. The combination of high flux (maximum thermal neutron fluxes of 1E15 neutrons per square centimeter per second and maximum fast [E>1.0 MeV] neutron fluxes of 5E14 neutrons per square centimeter per second) and large test volumes (up to 122 cm long and 12.7 cm diameter) provide unique testing opportunities. The current experiments in the ATR are for a variety of test sponsors - US government, foreign governments, private researchers, and commercial companies needing neutron irradiation services. There are three basic types of test configurations in the ATR. The simplest configuration is the sealed static capsule, which places the capsule in direct contact with the primary coolant. The next level of experiment complexity is an instrumented lead experiment, which allows for active control of experiment conditions during the irradiation. The most complex experiment is the pressurized water loop, in which the test sample can be subjected to the exact environment of a pressurized water reactor. For future research, some ATR modifications and enhancements are currently planned. This paper provides more details on some of the ATR capabilities, key design features, experiments, and future plans.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 전력전자학술대회 논문집(1)
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• pp.341-345
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• 2004

A high efficiency and low device stress voltage and current clamping BVS PWM asymmetrical half bridge converter is proposed in this paper. To achieve the ZVS of power switches along the wide load range, the transformer leakage inductor $L_{Ikg}$ is increased. Then, to solve the problem related to ringing in the secondary rectifier caused by the resonance between $L_{Ikg}$ and rectifier junction capacitors, the proposed converter employs a voltage and current clamping cell, which helps voltages and currents of rectifier diodes to be clamped at the output voltage and output current, respectively. Therefore, no RC-snubber for rectifier diodes is needed and a high efficiency as well as low noise output voltage can be realized. In addition, since all energy stored in $L_{Ikg}$ is transferred to the output side, the circulating energy problem can be effectively solved and duty loss does net exist. The operational principle, theoretical analysis, and design considerations are presented. To confirm the operation, validity, and features of the proposed circuit, experimental results from a 425W, 385-170Vdc prototype are presented.

• Nuclear Engineering and Technology
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• 제52권5호
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• pp.964-974
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• 2020

The small modular reactors (SMRs) of the integrated pressurized water reactor (IPWR) type have been widely developed owing to their enhanced safety features. The SMR-IPWR adopts passive residual heat removal system (PRHRS) to extract residual heat from the core. Because the PRHRS removes the residual heat using the latent heat of the water stored in the emergency cooldown tank, the PRHRS gradually loses its cooling capacity after the stored water is depleted. A quick restoration of the power supply is expected infeasible under station blackout accident condition, so an advanced PRHRS is needed to ensure an extended grace period. In this study, an advanced design is proposed to indirectly incorporate a dry air cooling tower to the PRHRS through an intermediate loop called indefinite PRHRS. The feasibility of the indefinite PRHRS was assessed through a long-term transient simulation using the MARS-KS code. The indefinite PRHRS is expected to remove the residual heat without depleting the stored water. The effect of the environmental temperature on the indefinite PRHRS was confirmed by parametric analysis using comparative simulations with different environmental temperatures.

• 한국CDE학회논문집
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• 제9권2호
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• pp.122-132
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• 2004

Progressive mesh representation and generation have become one of the most important issues in network-based computer graphics. However, current researches are mostly focused on triangular mesh models. On the other hand, solid models are widely used in industry and are applied to advanced applications such as product design and virtual assembly. Moreover, as the demand to share and transmit these solid models over the network is emerging, the generation and the transmission of progressive solid models depending on specific engineering needs and purpose are essential. In this paper, we present a Cellular Topology-based approach to generating and transmitting progressive solid models from a feature-based solid model for internet-based design and collaboration. The proposed approach introduces a new scheme for storing and transmitting solid models over the network. The Cellular Topology (CT) approach makes it possible to effectively generate progressive solid models and to efficiently transmit the models over the network with compact model size. Thus, an arbitrary solid model SM designed by a set of design features is stored as a much coarser solid model SM/sup 0/ together with a sequence of n detail records that indicate how to incrementally refine SM/sup 0/ exactly back into the original solid model SM = SM/sup 0/.

• 복식
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• 제65권4호
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• pp.124-136
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• 2015

Xinjiang Uygur Autonomous Region is the area with the most Muslim populations in China and the costume of this ethnic minority group was influenced from its surrounding environment and religion. Headgear is one of the important costume elements of Muslim ethnic minority such as Kazakh, Kirghiz, Uzbek, and Tadzhik people, and each group has developed narious forms of it. Especially, we can notice characteristics of headgear in Xinjiang Uygur and four ethnic minority groups through women's headgear pursuant to motive of wear, classification of type, differences and comparability with other areas. Thus, purpose of this study is to investigate women's headgear of Muslim ethnic minority in Xinjiang Uygur Autonomous Region. Based on local data at the Xinjiang Uygur Museum, the study referred to Chinese ethnic minority costume and literature data as well as advanced researches related to Islam, and analyzed characteristics of women's headgear of four ethnic groups in connection with Muslim formation background in Xinjiang Uygur. Women's headgear of Muslim ethnic minority in Xinjiang Uygur can be largely divided into three types; cylindrical, conical and hood type. Headgear was influenced not only by natural environment and weather for protection of body, but also by Islam. Along with strong desire for decoration and expression of racial features, it was used as a means of race discrimination and representation of identity. The religion of Islam within these four ethnic groups grew in accordance with tradition of existing nomadic tribes and regional characteristics, and women's headgear developed in various ways added with religious precepts and nomadic features. Taking everything into consideration, it is found that women's headgear of Kazakh, Kirghiz, Uzbek, and Tadzhik people developed, adopting their own living style and features of minority races instead of remaining identical to the headgear type of Muslim countries in other area.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2013년도 춘계학술대회
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• pp.757-759
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• 2013

수 년 전까지만 해도 Verilog나 VHDL과 같은 하드웨어 기술언어 (HDL)를 사용한 레지스터 전송수준의 설계 기법은 기존의 회로도에 의존했던 방법에 비해 최첨단의 기술로 인식되었고 현재까지도 디지털 회로를 설계하는 방법으로 가장 널리 사용되고 있다. 하지만 공정 기술의 발전으로 반도체 칩의 트랜지스터 집적도가 십억 개 단위를 훌쩍 넘어서는 시대가 열림에 따라, 레지스터 전송 수준에서 회로를 설계하는 것은 너무도 복잡한 일이 되어버려, 더 이상 시대의 요구에 부응하지 못하여 설계 패러다임이 상위수준에서 설계와 합성이 이루어지는 쪽으로 변화하여야 한다. 블루스펙 HDL은 현재까지 개발된 HDL 중 유일하게 시스템 레벨에서 회로를 설계하는 것을 가능하게 함과 동시에 합성이 가능한 코드를 생성해주는 언어이다. 본 고에서는, 아직 많이 알려지지는 않았지만, 진화한 설계 패러다임을 지향하는 블루스펙 HDL에 대해 소개하고 분석하도록 한다.

• Journal of Computational Design and Engineering
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• 제3권2호
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• pp.161-177
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• 2016

In history based parametric CAD modeling systems, persistent identification of the topological entities after design modification is mandatory to keep the design intent by recording model creation history and modification history. Persistent identification of geometric and topological entities is necessary in the product design phase as well as in the re-evaluation stage. For the identification, entities should be named first according to the methodology which will be applicable for all the entities unconditionally. After successive feature operations on a part body, topology based persistent identification mechanism generates ambiguity problem that usually stems from topology splitting and topology merging. Solving the ambiguity problem needs a complex method which is a combination of topology and geometry. Topology is used to assign the basic name to the entities. And geometry is used for the ambiguity solving between the entities. In the macro parametrics approach of iCAD lab of KAIST a topology based persistent identification mechanism is applied which will solve the ambiguity problem arising from topology splitting and also in case of topology merging. Here, a method is proposed where no geometry comparison is necessary for topology merging. The present research is focused on the enhancement of the persistent identification schema for the support of ambiguity problem especially of topology splitting problem and topology merging problem. It also focused on basic naming of pattern features.

• Journal of Electrical Engineering and Technology
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• 제8권2호
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• pp.326-330
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• 2013

The Korea Superconducting Tokamak Advanced Research (KSTAR) device is an advanced superconducting tokamak to establish scientific and technological bases for attractive fusion reactor. This device requires 3.5 Tesla of toroidal field (TF) for plasma confinement, and requires a strong poloidal flux swing to generate an inductive voltage to produce and sustain the tokamak plasma. KSTAR was originally designed to have 16 serially connected TF magnets for which the nominal current rating is 35.2 kA. KSTAR also has 7 pairs of poloidal field (PF) coils that are driven to 1 MA/sec for generation of the tokamak plasma according to the operation scenarios. The KSTAR Magnet Power Supply (MPS) was dedicated to the superconducting (SC) coil commissioning and $2^{nd}$ plasma experiment as a part of the system commissioning. This paper will describe key features of KSTAR MPS for the $2^{nd}$ plasma experiment, and will also report the engineering and commissioning results of the magnet power supplies.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2008년도 춘계종합학술대회 A
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• pp.225-228
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• 2008

In this paper, we presented our implementation of a counter mode AES based on Virtex4 FPGA. Our design exploits three advanced features: composite field arithmetic SubByte, efficient MixColumn transformation, and On-the-Fly Key-Scheduling for fully pipelined architecture. By pipelining the composite field implementation of the S-box, the area cost is reduced to average 17 percent. By designing the On-the-Fly key scheduling, we implemented an efficient key-expander module which is specialized for a pipelined architecture.

• 한국경영과학회지
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• 제13권1호
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• pp.51-64
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• 1988

A new approach to the logical design of 4NF database shceme, which can be easily automated, is proposed. The main features of the approach are : introduction of a single attribute right hand side, extension of the concept of independent relations, semantic analysis, and adaoption of dependency matrix. The underlying viewpoints of functional relationships of the approach are different from Fagin's in that we distinguish functional and multivalued dependency in terms of cardinality. An algorithm for automatic generation of fourth normal form is presented and implemented.