• Nuclear Engineering and Technology
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• 제49권2호
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• pp.306-312
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• 2017

The purpose of this research is to introduce the technical standard of accident sequence precursor (ASP) analysis, and to propose a case study using the dynamic-probabilistic safety assessment (D-PSA) approach. The D-PSA approach can aid in the determination of high-risk/low-frequency accident scenarios from all potential scenarios. It can also be used to investigate the dynamic interaction between the physical state and the actions of the operator in an accident situation for risk quantification. This approach lends significant potential for safety analysis. Furthermore, the D-PSA approach provides a more realistic risk assessment by minimizing assumptions used in the conventional PSA model so-called the static-PSA model, which are relatively static in comparison. We performed risk quantification of a steam generator tube rupture (SGTR) accident using the dynamic event tree (DET) methodology, which is the most widely used methodology in D-PSA. The risk quantification results of D-PSA and S-PSA are compared and evaluated. Suggestions and recommendations for using D-PSA are described in order to provide a technical perspective.

• 정보과학회 논문지
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• 제43권10호
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• pp.1067-1072
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• 2016

실행코드만으로 소프트웨어 간의 유사성을 비교하거나 표절을 검사하기 위해 소프트웨어만의 고유한 특징인 소프트웨어 버스마크를 이용한다. 일반적으로 소프트웨어 버스마크는 추출 방법에 따라 정적 버스마크와 동적 버스마크로 구분되고, 추출된 방법에 따라 장단점이 뚜렷하게 나타난다. 본 논문에서는 동적 분석을 이용하여 API 시퀀스 버스마크를 추출하고 실행코드 간의 유사성 검사에 이용하는 방법을 제안한다. 제안하는 동적 시퀀스 버스마크는 프로그램이 실행되는 과정에서 호출되는 모든 API 함수 및 시스템 호출을 포함하는 기존의 방법과는 다르게 실행코드 내에 정의되어 있는 API 함수만으로 구성된 API 시퀀스를 이용한다. 추출된 동적 버스마크는 프로그램의 시작에서 종료까지 호출되는 API 시퀀스이며 이를 효율적으로 비교하기 위해 서열정렬 알고리즘을 활용한 유사성 척도를 사용한다. 여러 오픈소스 소프트웨어를 비교하여 버스마크의 신뢰성과 강인성을 검증하였다. 제안하는 동적 API 시퀀스 버스마크는 실행코드의 유사성 검사에 용이하게 활용될 수 있을 것으로 기대된다.

• 전기전자학회논문지
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• 제27권1호
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• pp.93-102
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• 2023

악성코드 분석을 위한 기술 중 하나로 실행 프로그램의 함수 호출 관계를 시퀀스 또는 그래프 작성한 후, 그 결과를 분석하는 기술이 제안되었다. 이러한 기술들은 일반적으로 실행 프로그램 파일의 정적 분석을 통해 함수 호출 코드를 분석하고, 함수 호출 관계를 시퀀스 또는 그래프로 정리한다. 그러나 난독화 된 실행 프로그램의 경우, 실행 프로그램 파일의 구성이 표준구성과 다르기 때문에 정적분석 만으로는 함수 호출관계를 명확히 분석하기 어렵다. 본 논문에서는 난독화 된 실행 프로그램의 함수 호출관계를 분석하기 위한 동적 분석 방법을 제안하고, 제안된 기술을 이용하여 함수 호출관계를 그래프로 구성하는 방법을 제안한다.

• 한국통신학회논문지
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• 제27권7B호
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• pp.706-718
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• 2002

In bluetooth system, there are two kinds of interference. One is the frequency static interference, for example 802.11 direct sequence, the interferer uses fixed frequency band. Another is frequency dynamic interference, for example other piconets or 802.11 frequency hopping, the interferer uses dynamic frequency channel and cant be estimated. In this paper we introduce a novel solution of hybrid method of Listen-Before-Talk (LBT) and Adaptive Frequency Hopping (AFH) to address the coexistence of bluetooth and Direct Sequence of wireless local area network (WLAN). Before any bluetooth packet transmission, in the turn around time of the current slot, both the sender and receiver sense the channel whether there is any transmission going on or not. If the channel is busy, packet transmission is withdrawn until another chance. This is the LBT in Bluetooth. Because of asymmetry sense ability of WLAN and bluetooth, AFH is introduced to combat the left front-edge packet collisions. In monitor period of AFH, LBT is performed to label the channels with static interference. Then, all the labeled noisy channels are not used in the followed bluetooth frequency hopping. In this way, both the frequency dynamic and frequency static interference are effectively mitigated. We evaluate the solution through packet collision analysis and a detail realistic simulation with IP traffic. It turns out that the hybrid method can combat both the frequency dynamic and frequency static interference. The packet collision analysis shows it almost doubles the maximal system aggregate throughput. The realistic simulation shows it has the least packet loss.

• 대한통합의학회지
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• 제10권1호
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• pp.101-108
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• 2022

Purpose : This study was conducted to investigate the effect of muscle taping and joint taping on static and dynamic balance in normal adults with chronic ankle instability. Methods : The subjects of this study were 32 people who met the inclusion criteria. This cross-sectional study was conducted using the Kinesio tape, an elastic tape, was used. Subjects were randomized to exclude the effect of sequence, and no taping, joint taping, and muscle taping were applied as taping interventions. One-leg standing test and a Functional reach test were conducted to measure static balance, and Y-balance test was conducted to measure dynamic balance. One way repeated ANOVA was performed to investigate the difference in balance ability according to the taping intervention. If there was a significant difference, a post-hoc was performed using the Bonferroni method. Results : In the case of static balance, joint taping showed more significant results than did no taping and muscle taping (p<.05), and muscle taping showed more significant results than did no taping (p<.05). In the case of dynamic balance, muscle taping showed significantly larger results than did no taping and joint taping (p<.05) and joint taping showed significantly larger results than did no taping (p<.05). Conclusion : This study found that mechanical stimulation of muscles and joint compression by elastic taping increased ankle stability and improved static and dynamic balance. In particular, for static balance, joint taping was more effective than muscle taping, and for dynamic balance, muscle taping was more effective than joint taping. Applying the appropriate taping method to individual subjects has the advantage of maximizing the therapeutic effect for the recovery of balance ability. Similarly, the application of various tapings to subjects with ankle instability will have a positive effect on functional improvement.

• 한국정밀공학회지
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• 제18권11호
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• pp.34-41
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• 2001

This study is to investigate the energy absorption characteristics of CFRP(Carbon-Fiber Reinforced Plastics) tubes on static and dynamic tests. Axial static compression tests have been carried out using the static testing machine(Shin-gang buckling testing machine) and dynamic compression tests have been utilized using an vertical crushing testing machine. When such tubes are subjected to crushing loads, the response is complex and depends on the interaction between the different mechanisms that could control the crushing process. The collapse characteristics and energy absorption have been examined for various tubes. Energy absorption of the tubes are increased as changes in the lay-up which may increase the modulus of tubes. The results have been varied significantly as a function of ply orientation and interlaminar number.

• Composites Research
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• 제20권1호
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• pp.1-7
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• 2007

본 논문에서는 골프클럽샤프트의 정적특성의 최적화 방법론을 제시하였다. 복합재료를 사용한 샤프트의 최적성능향상을 위한 쉬트 프리프레그의 적층순서를 구하였다. 클럽샤프트의 굽힘 강성과 비틀림 강성의 동시 최적화를 위하여 새로운 최적화 목적함수를 제시하였다. 샤프트의 정적특성 분석을 위하여 고전적층 이론을 적용하였으며 최적화 방법으로서 적층순서를 설계변수로 정의하는 유전알고리즘을 사용하였다. 또한 얻어진 최적적층순서를 바탕으로 한 샤프트의 동적특성을 분석하였다.

• Structural Engineering and Mechanics
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• 제37권3호
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• pp.267-283
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• 2011

Although earthquakes generate random cyclic lateral loading on structures, a quasi-static cyclic loading pattern with gradually increasing amplitude has been commonly used in the laboratory tests because of its relatively low cost and simplicity compared with pseudo-dynamic and shake table tests. The number, amplitudes and sequence of cycles must be chosen appropriately as important parameters of a quasi-static cyclic loading pattern in order to account for cumulative damage matter. This paper aims to reach a new cyclic displacement pattern to be used in quasi-static tests of well-confined, flexure-dominated reinforced concrete (RC) columns. The main parameters of the study are sectional dimensions, percentage of longitudinal reinforcement, axial force intensity and earthquake types, namely, far-fault and near-fault.

• 정보과학회 논문지
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• 제43권3호
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• pp.289-295
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• 2016

악성코드 개발자들은 악성코드 탐지를 회피하기 위하여 변종 악성코드를 유포한다. 정적 분석 기반의 안티 바이러스로는 변종 악성코드를 탐지하기 어려우며, 따라서 API 호출 정보 기반의 동적 분석이 필요하다. 본 논문에서는 악성코드 분석가의 변종 악성코드 패밀리 분류에 도움을 줄 수 있는 악성코드 패밀리 추천 기법을 제안하였다. 악성코드 패밀리의 API 호출 정보를 동적 분석을 통하여 추출하였다. 추출한 API 호출 정보에 다중 서열 정렬 기법을 적용하였다. 정렬 결과로부터 각 악성코드 패밀리의 시그니쳐를 추출하였다. 시그니쳐와의 유사도를 기준으로, 제안하는 기법이 새로운 악성코드의 패밀리 후보를 3개까지 추천하도록 하였다. 실험을 통하여 제안한 악성코드 패밀리 추천 기법의 정확도를 측정하였다.

• International Journal of Aeronautical and Space Sciences
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• 제3권2호
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• pp.59-66
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• 2002

A vertical test stand based on launcher propulsion system was constructed and several tests for the determination of cyclogram were carried out. To make an accurate estimation, static and dynamic pressures were measured and analyzed. Especially, static pressure measurements using fast response sensors without extension tubes were used to determine operation sequence more evidently. The standard operation times of final valves were determined in cold flow tests with an engine head, and fire formation time in combustion chamber was checked in an ignition test with an ignitor only. On the basis of these tests, ignition sequence was established and combustion test cyclogram was finally determined. According to combustion test, test results were well matched with the determined cyclogram within 0.05 sec.