• Proceedings of the Korean Nuclear Society Conference
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• 1996.05b
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• pp.493-498
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• 1996

A PC window-based computer code, CONPAS(CONtainment Performance Analysis System), has been developed to integrate the numerical, graphical and results-operation aspects of Level 2 probabilistic safety assessments (PSA) for nuclear power plants automatically. As a main logic for accident progression analysis, it employs a concept of the small containment phenomenological event tree(CPET) helpful to trace out visually individual accident progressions and of the large supporting event tree(LSET) for its detailed quantification. Compared with other existing computer codes for Level 2 PSA, the CONPAS code provides several advanced features: computational aspects including systematic uncertainty analysis, importance analysis, and sensitivity analysis, reporting aspects including tabling and graphic, and user-friend interface.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1997.10a
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• pp.50-54
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• 1997

To trace crack propagation process in cracked structure is very important thing in view of maintenance and repair of the structure. But it is a little troublesome work due to the continuous remesh work, because a new crack tip is formed in each propagation step. It is more difficult if it should be studied in the three dimensional region. By the way, lately the CFG(Cornell Fracture Group) makes the crack propagation analysis in three dimensional problems possible by developing a new code for them. The use of the code will be expected to spread widely. So a brief introduction of the contents of the code via the theorems used and numerical examples is the purpose of this paper.

• International Journal of CAD/CAM
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• v.11 no.1
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• pp.27-32
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• 2011

The increase in the productivity and the assurance of quality machining on the NC machines depends on, amongst other things, the perfection of the programming using adequate methods of interpolation. The programming language is until now based on the code ISO 6983 which defines the principles of the code G. This latter is not well adapted to the new strategies of machining imposed by the machining of complex surfaces and machining at high speed with the increasingly more severe requirements of precision. The CNC which adopt the interpolation of NURBS (Non Uniform Rational B-spline) are very rare (FANUC Siemens${\ldots}$). Based on the advantages of NURBS (continuity, flexibility, smoothing$.{\ldots}$), new formats G are currently developed but their use is still very limited. Our work consists on putting forward these new approaches of programming using the interpolation of NURBS. For this reason, a program capable to trace NURBS trajectories under Visual BASIC 6.0 was developed. This program was used thereafter in CAM software for the generation of NURBS formats like their new formats NC.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.04a
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• pp.502-505
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• 2014

최근 들어, 모바일 기기의 시스템을 장악하여 중요 정보를 빼내는 등의 악성 행위를 위해 Code Reuse Attack (CRA) 이 널리 사용되고 있다. 이러한 CRA 를 막기 위한 방법으로 branch 의 trace 를 분석하여 CRA 고유의 특성을 찾아내는 Signature 기반 탐지 기술이 있다. 이러한 탐지 기술을 효율적으로 지원하기 위하여, 본 논문에서는 ARM 프로세서용 바이너리를 분석하여, signature 분석을 위해 필수적으로 분석되어야 하는 gadget 의 크기를 빠르게 접근할 수 있는 meta-data 를 생성하는 기술을 제안한다. 이러한 meta-data 를 활용하는 방식은 gadget 의 크기를 계산하는 추가적인 코드의 수행을 제거해 주므로, 더욱 효율적으로 CRA 를 탐지할 수 있도록 도와준다. 실험 결과, 이러한 meta-data 는 본래의 바이너리 코드 대비 9% 만의 크기 증가를 일으키는 것으로 나타났다.

• Nuclear Engineering and Technology
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• v.50 no.3
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• pp.356-367
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• 2018

A series of tests dedicated to station blackout (SBO) accident scenarios have been recently performed at the $Prim{\ddot{a}}rkreislauf-Versuchsanlage$ (primary coolant loop test facility; PKL) facility in the framework of the OECD/NEA PKL-3 project. These investigations address current safety issues related to beyond design basis accident transients with significant core heat up. This work presents a detailed analysis using the best estimate thermal-hydraulic code TRACE (v5.0 Patch4) of different SBO scenarios conducted at the PKL facility; failures of high- and low-pressure safety injection systems together with steam generator (SG) feedwater supply are considered, thus calling for adequate accident management actions and timely implementation of alternative emergency cooling procedures to prevent core meltdown. The presented analysis evaluates the capability of the applied TRACE model of the PKL facility to correctly capture the sequences of events in the different SBO scenarios, namely the SBO tests H2.1, H2.2 run 1 and H2.2 run 2, including symmetric or asymmetric secondary side depressurization, primary side depressurization, accumulator (ACC) injection in the cold legs and secondary side feeding with mobile pump and/or primary side emergency core coolant injection from the fuel pool cooling pump. This study is focused specifically on the prediction of the core exit temperature, which drives the execution of the most relevant accident management actions. This work presents, in particular, the key improvements made to the TRACE model that helped to improve the code predictions, including the modeling of dynamical heat losses, the nodalization of SGs' heat exchanger tubes and the ACCs. Another relevant aspect of this work is to evaluate how well the model simulations of the three different scenarios qualitatively and quantitatively capture the trends and results exhibited by the actual experiments. For instance, how the number of SGs considered for secondary side depressurization affects the heat transfer from primary side; how the discharge capacity of the pressurizer relief valve affects the dynamics of the transient; how ACC initial pressure and nitrogen release affect the grace time between ACC injection and subsequent core heat up; and how well the alternative feeding modes of the secondary and/or primary side with mobile injection pumps affect core quenching and ensure stable long-term core cooling under controlled boiling conditions.

• Nuclear Engineering and Technology
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• v.30 no.1
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• pp.58-74
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• 1998

A PC window-based computer code, CONPAS (CONtainment Performance Analysis System), has been developed to integrate the numerical, graphical, and results-operation aspects of Level 2 probabilistic safety assessments (PSA) for nuclear power plants automatically. As a main logic for accident progression analysis, it employs a concept of the small containment phenomenological event tree (CPET) helpful to trace out visually individual accident progressions and of the detailed supporting event tree (DSET) for its detailed quantification. For the integrated analysis of Level 2 PSA, the code utilizes five distinct, but closely related modules. Its computational feasibility to real PSAs has been assessed through an application to the UCN 3&4 full scope Level 2 PSA. Compared with other existing computer codes for Level 2 PSA, the CONPAS code provides several advanced features: (1) systematic uncertainty analysis / importance analysis / sensitivity analysis, (2) table / graphical display & print, (3) employment of the recent Level 2 PSA technologies, and (4) highly effective user interface. The main purpose of this paper is to introduce the key features of CONPAS code and results of its feasibility study.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.3A
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• pp.337-346
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• 2004

Punctured convolutional codes increase transmission efficiency without increasing hardware complexity. However, Viterbi decoder supporting punctured codes requires long decoding length and large survivor memory to achieve sifficiently low bit error rate (BER), when compared to the Viterbi decoder for a rate 1/2 convolutional code. This Paper presents novel architecture adopting a pipelined trace-forward unit reducing survivor memory requirements in the Viterbi decoder. The proposed survivor path architecture reduces the memory requirements by removing the initial decoding delay needed to perform trace-back operation and by accelerating the trace-forward process to identify the survivor path in the Viterbi decoder. Experimental results show that the area of survivor path unit has been reduced by 16％ compared to that of conventional hybrid survivor path unit.

• Nuclear Engineering and Technology
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• v.54 no.5
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• pp.1860-1873
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• 2022

Nuclear thermal-hydraulic system analysis codes have been developed to comprehensively model nuclear reactor systems to evaluate the safety of a nuclear reactor system. For analyzing complex systems with finite computational resources, system codes usually solve simplified fluid equations for coarsely discretized control volumes with one-dimensional assumptions and replace source terms in the governing equations with constitutive relations. Wall boiling heat transfer models are regarded as essential models in nuclear safety evaluation among many constitutive relations. The wall boiling heat transfer models of two widely used nuclear system codes, RELAP5 and TRACE, are analyzed in this study. It is first described how wall heat transfer models are composed in the two codes. By utilizing the same method described in Part 1 paper, heat fluxes from the two codes are compared under the same thermal-hydraulic conditions. The significant factors for the differences are identified as well as at which conditions the non-negligible difference occurs. Steady-state simulations with both codes are also conducted to confirm how the difference in wall heat transfer models impacts the simulation results.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.9
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• pp.911-915
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• 2008

Software birthmark is the inherent characteristics that can identify a program. In this paper, we propose a Java class theft detection technique based on static API traces of class files. We utilize control flow analysis to increase resilience, and we apply the semi-global alignment trace comparison algorithm to increase credibility. The credibility and resilience experiments for XML parsers show that our birthmark is more efficient than existing birthmarks.

• English Language & Literature Teaching
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• v.17 no.3
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• pp.99-118
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• 2011

Research on strategic Code-Switching (CS) of second language learners in teaching English in English (TEE) program provides an elaborate framework for analyzing how learners manage to express themselves in spite of their limited knowledge of the target language. This research presupposes that L2 learners' CS presents innovative solutions for communicative strategy, and that CS used as communicative strategy can promote L2 learners' language acquisition. The major questions of current research involve examining the significant patterns of different functions of CS in L2 learners' interaction and investigating L2 learners' CS styles according to the different functions of CS. The implication of CS utility is regarded as a teaching technique in the TEE program. Recorded transcript is analyzed to trace the same pattern and the categorization of CS as well as to recognize the functions of CS and their ratio. Hence, this leads to the conclusion that learners' negotiation between code selection and communication intention occurs in patterns. The learners' CS tends to be predictable, reproductive, and systematic, as one of the language acquisition phases. Therefore, the attention to the CS in the TEE program should be redirected in communication substantiality toward the principles of pragmatics. As an additional advantage of the CS analysis, this research elaborates on a conceptual acceptance of CS as a set of learners' strategies in the TEE program.