• Nuclear Engineering and Technology
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• 제48권2호
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• pp.330-338
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• 2016

The U-Zr or U-TRU-Zr cylindrical metallic fuel slug used in fast reactors is known to swell significantly and to grow during irradiation. In neutronics simulations of metallic-fueled fast reactors, it is assumed that the slug has swollen and contacted cladding, and the bonding sodium has been removed from the fuel region. In this research, a realistic burnup-dependent fuel-swelling simulation was performed using Monte Carlo code McCARD for a single-batch compact sodium-cooled breed-and-burn reactor by considering the fuel-swelling behavior reported from the irradiation test results in EBR-II. The impacts of the realistic burnup-dependent fuel swelling are identified in terms of the reactor neutronics performance, such as core lifetime, conversion ratio, axial power distribution, and local burnup distributions. It was found that axial fuel growth significantly deteriorated the neutron economy of a breed-and-burn reactor and consequently impaired its neutronics performance. The bonding sodium also impaired neutron economy, because it stayed longer in the blanket region until the fuel slug reached 2% burnup.

• 한국통신학회논문지
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• 제35권3B호
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• pp.421-430
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• 2010

최근 통신망이 광대역화 됨에 따라 다양한 양방향 TV 서비스를 제공하는 IPTV(Internet Protocol Television)서비스가 증가하고 있다. 그러나 IPTV의 셋톱박스와 스마트 카드 간에 전달되는 데이터가 셋톱박스 내에서 대부분 전달되기 때문에 맥코맥 핵 공격을 이용하여 불법적으로 콘텐츠 내용에 접근하여 합법적인 권한을 획득하는 불법 사용자를 완벽하게 예방할 수 없다. 이 논문에서는 스마트카드로부터 셋톱박스까지 연결된 데이터 라인을 불법 사용자가 동일 기종의 다른 셋톱박스를 이용하여 불법적으로 IPTV 서비스의 접근 허가를 받으려는 맥코맥 핵공격(McComac Hack Attack)을 예방하기 위한 셋톱박스 접근 보안 모델을 제안한다. 제안 모델은 사전에 셋톱박스에 사용가능한 스마트 카드의 상태정보를 등록하여 불법적으로 접근허가를 승인받으려는 사용자를 인증서버에서 점검하여 점검 결과를 셋톱박스에 통보하여 불법 사용자를 사전에 예방한다. 특히, 제안 모델은 Pseudo 랜덤 함수를 통해 생성된 임의의 난수와 비밀값을 통해 이웃 링크 설립과 상호 인증 과정에 사용되는 공개키에 적용하여 셋탑박스에 대한 보안을 강화하고 있다.

• Nuclear Engineering and Technology
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• 제47권7호
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• pp.791-803
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• 2015

The effective cross sections (XSs) in the direct whole core calculation code nTRACER are evaluated by the equivalence theory-based resonance-integral-table method using the WIMS-based library as an alternative to the subgroup method. The background XSs, as well as the Dancoff correction factors, were evaluated by the enhanced neutron-current method. A method, with pointwise microscopic XSs on a union-lethargy grid, was used for the generation of resonance-interference factors (RIFs) for mixed resonant absorbers. This method was modified by the intermediate-resonance approximation by replacing the potential XSs for the non-absorbing moderator nuclides with the background XSs and neglecting the resonance-elastic scattering. The resonance-escape probability was implemented to incorporate the energy self-shielding effect in the spectrum. The XSs were improved using the proposed method as compared to the narrow resonance infinite massbased method. The RIFs were improved by 1% in $^{235}U$, 7% in $^{239}Pu$, and >2% in $^{240}Pu$. To account for thermal feedback, a new feature was incorporated with the interpolation of pre-generated RIFs at the multigroup level and the results compared with the conventional resonance-interference model. This method provided adequate results in terms of XSs and k-eff. The results were verified first by the comparison of RIFs with the exact RIFs, and then comparing the XSs with the McCARD calculations for the homogeneous configurations, with burned fuel containing a mixture of resonant nuclides at different burnups and temperatures. The RIFs and XSs for the mixture showed good agreement, which verified the accuracy of the RIF evaluation using the proposed method. The method was then verified by comparing the XSs for the virtual environment for reactor applicationbenchmark pin-cell problem, as well as the heterogeneous pin cell containing burned fuel with McCARD. The method works well for homogeneous, as well as heterogeneous configurations.

• 한국정보과학회논문지:소프트웨어및응용
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• 제32권6호
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• pp.486-501
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• 2005

XPDL(XML Process Definition Language)은 프로세스 정의 교환을 위하여 WfMC에서 제안한 XML 기반 언어이다. 본 논문에서는 워크플로우 프로세스의 정의와 교환을 위하여 XPDL 문서의 구조(Schema)를 UML 다이어그램으로 모델링하여 기업들 간의 상호연동과 협업을 위한 업무흐름 파악을 용이하게 하는 모델을 제안한다. 이를 위해 XPDL 문서를 UML의 클래스 다이어그램과 액티비티 다이어그램으로 변환하는 사상 규칙을 정의하여, XPDL 프로세스 메타모델(Meta-Model)를 구성하는 각 엘리먼트는 클래스 다이어그램으로 모델링하고, 프로세스 액티비티(Process Activity)는 액티비티 다이어그램으로 모델링하는 기법을 제안한다. 또한 제안된 기법을 "신용 카드 상태 체크 시스템"의 워크플로우에 대한 XPDL 문서을 적용하여 제안된 기법의 유효성을 검증한다.

• Nuclear Engineering and Technology
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• 제56권3호
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• pp.772-784
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• 2024

The hexagonal nodal code RENUS has been enhanced to handle irregularly deformed hexagonal assemblies. The underlying RENUS methods involving triangle-based polynomial expansion nodal (T-PEN) and corner point balance (CPB) were extended in a way to use line and surface integrals of polynomials in a deformed hexagonal geometry. The nodal calculation is accelerated by the coarse mesh finite difference (CMFD) formulation extended to unstructured geometry. The accuracy of the unstructured nodal solution was evaluated for a group of 2D SFR core problems in which the assembly corner points are arbitrarily displaced. The RENUS results for the change in nuclear characteristics resulting from fuel deformation were compared with those of the reference McCARD Monte Carlo code. It turned out that the two solutions agree within 18 pcm in reactivity change and 0.46% in assembly power distribution change. These results demonstrate that the proposed unstructured nodal method can accurately model heterogeneous thermal expansion in hexagonal fueled cores.

• 정보보호학회논문지
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• 제16권4호
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• pp.33-41
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• 2006

RSA 암호 시스템은 IC카드, 모바일 시스템 및 WPKI, 전자화폐, SET, SSL 시스템 등에 많이 사용된다. RSA는 모듈러 지수승 연산을 통하여 수행되며, Montgomery 곱셈기를 사용하는 것이 효율적이라고 알려져 있다. Montgomery 곱셈기에서 임계 경로 지연 시간(Critical Path Delay)은 세 피연산자의 덧셈에 의존하고 캐리 전파를 효율적으로 처리하는 문제는 Montgomery 곱셈기의 효율성에 큰 영향을 미친다. 최근 캐리 전파를 제거하는 방법으로 캐리 저장 덧셈기(Carry Save Adder, CSA)를 사용하는 연구가 계속 되고 있다. McIvor외 세 명은 지수승 연산에 최적인 CSA 3단계로 구성된 Montgomery 곱셈기와 CSA 2단계로 구성된 Montgomery 곱셈기를 제안했다. 시간 복잡도 측면에서 후자는 전자에 비해 효율적이다. 본 논문에서는 후자보다 빠른 연산을 수행하기 위해 캐리 전파 제거 특성을 가진 이진 부호 자리(Signed-Digit SD) 수 체계를 사용한다. 두 이진 SD 수의 덧셈을 수행하는 잉여 이진 덧셈기(Redundant Binary Adder, RBA)를 새로 제안하고 Montgomery 곱셈기에 적용한다. 기존의 RBA에서 사용하는 이진 SD 덧셈 규칙 대신 새로운 덧셈 규칙을 제안하고 삼성 STD130 $0.18{\mu}m$ 1.8V 표준 셀 라이브러리에서 지원하는 게이트들을 사용하여 설계하고 시뮬레이션 하였다. 그 결과 McIvor의 2 방법과 기존의 RBA보다 최소 12.46%의 속도 향상을 보였다.

• 대한가정학회지
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• 제44권1호
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• pp.25-35
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• 2006

This study investigated the scheme for correctly making Korean fashion design known to the world. It attempted to increase the influence of the Eighteenth Century Costume in contemporary fashion. During the 18th century, France had an almost complete monopoly of fashion. Growing out the fairyland atmosphere of the French Court and often conceived of as ennui by personal vanity, this fashion was a product of an age which sought at any price to live life with supreme grace. Most of the special costume exhibitions in the Metropolitan Museum of Art are planned and directed by Polaire Weissman, Diana Vreeland, Richard Martin, Harold Koda. The Costume Institute has held exhibitions of the Eighteenth Century Costume several times such as "Museum Period Rooms Re-Occupied in Style," "the Eighteenth Century Women," "the Ceaseless Century," "Dangerous Liaisons," etc. Especially, the exhibition of "Dangerous Liaisons" is organized in ten parts such as the Portrait, the Levee, the Music Lesson, the Withdrawing Room, the Broken Vase, the Favorite, the Masked Beauty, the Card Game, the Late Supper, and the Shop. Using the eighteenth century as its touchstone, The Ceaseless Century proceeds differently, not seeking the short distance between a discrete present and the multiple past but rather showing the complicated navigation that comes of revivalism swing to and fro on the timeline of history and sensibility. The designers featured include Karl Lagerfeld, Gianni Versace, Vivienne Westwood, Jean Paul Gaultier, Christian Dior, Cristobal Balencicga, Christian Lacroix, Stella McCartney forChloe, Olivier Theyskens, Alexander McQueen, etc. Therefore, Korean designers should refrain from (Ed-confirm) the foreign collection without a clear purpose and should devote their effort to create with an active attitude.

• 한국산업정보학회논문지
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• 제11권2호
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• pp.86-97
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• 2006

90년대 중반에 이르러 정보화 사업의 규모가 커지면서 실패사례가 빈번히 발생함에 따라 정보화 성과평가에 대한 관심이 대두되고 있다. 또한 최고경영자들이 관심을 가지고 있는 정보시스템에 대한 투자비용과 정보시스템의 성과와의 관계에 대한 연구가 매우 미흡하여 이 분야에 대한 연구의 필요성이 고조 되고 있다. 본 연구에서는 DeLone & McLean의 정보시스템 성공모델과 이국희의 기업정보시스템 평가모델 및 Kaplan & Norton의 균형성과지표(BSC)를 바탕으로, 정보시스템의 비용대비 투자효과를 측정하였다. 모형 내 변수들 간의 관계성을 연구하기 위하여 경로분석을 실시한 결과, 투자비용은 시스템의 질 및 정보의 질에, 시스템의 질과 정보의 질은 사용자 만족도에, 사용자 만족도는 재무적성과, 고객만족도, 내부업무 프로세스에 대해 유의적인 영향을 미치는 것으로 나타났다. 본 연구를 통해 정보시스템에 대한 적절한 투자가 사용자의 만족도를 높여 궁극적으로 조직 성과로 귀결된다는 것이 증명되었다.

• Archives of Plastic Surgery
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• 제49권2호
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• pp.174-183
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• 2022

Management of traumatic skull base fractures and associated complications pose a unique reconstructive challenge. The goals of skull base reconstruction include structural support for the brain and orbit, separation of the central nervous system from the aerodigestive tract, volume to decrease dead space, and restoration of the three-dimensional appearance of the face and cranium with bone and soft tissues. An open bicoronal approach is the most commonly used technique for craniofacial disassembly of the bifrontal region, with evacuation of intracranial hemorrhage and dural repair performed prior to reconstruction. Depending on the defect size and underlying patient and operative factors, reconstruction may involve bony reconstruction using autografts, allografts, or prosthetics in addition to soft tissue reconstruction using vascularized local or distant tissues. The vast majority of traumatic anterior cranial fossa (ACF) injuries resulting in smaller defects of the cranial base itself can be successfully reconstructed using local pedicled pericranial or galeal flaps. Compared with historical nonvascularized ACF reconstructive options, vascularized reconstruction using pericranial and/or galeal flaps has decreased the rate of cerebrospinal fluid (CSF) leak from 25 to 6.5%. We review the existing literature on this uncommon entity and present our case series of n = 6 patients undergoing traumatic reconstruction of the ACF at an urban Level 1 trauma center from 2016 to 2018. There were no postoperative CSF leaks, mucoceles, episodes of meningitis, or deaths during the study follow-up period. In conclusion, use of pericranial, galeal, and free flaps, as indicated, can provide reliable and durable reconstruction of a wide variety of injuries.

• Nuclear Engineering and Technology
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• 제52권9호
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• pp.1896-1906
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• 2020

The BEAVRS (Benchmark for Evaluation and Validation of Reactor Simulation) benchmark calculations were performed by DeCART stand-alone and DeCART/MATRA multi-physics coupled code system to verify their accuracy. The solutions of DeCART stand-alone calculations for the control rod bank worth, detector signal, isothermal temperature coefficient, and critical boron concentration agreed very well with the measurements. The root-mean-square errors of the boron letdown curves for two-cycles were less than about 20 ppm, while the individual and total control rod bank worth agreed well within 7.3% and 2.4%, respectively. For the BEAVRS benchmark calculations at the beginning of burnup, the difference between DeCART simplified thermal-hydraulic stand-alone and DeCART/MATRA coupled calculations were not significantly large. Therefore, it is concluded that both the DeCART stand-alone code and the DeCART/MATRA multi-physics coupled code system have the capabilities to generate high fidelity transport solutions at core follow calculations.