• 정보과학회 컴퓨팅의 실제 논문지
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• 제21권3호
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• pp.257-262
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• 2015

소프트웨어가 복잡해짐에 따라 개발자가 인지하지 못하는 버그가 증가하고 있다. 공격자들은 시스템을 공격하거나 악성코드를 유포하기 위해 이와 같은 소프트웨어 버그 중 보안에 취약한 버그를 이용한다. 대표적인 방법으로 문서, 멀티미디어 등의 파일을 조작하여 보안에 취약한 버그를 발생시키는 방법으로 최근 지능적 지속 공격 빈번하게 사용되었다. 이에, 본 논문에서는 소프트웨어의 보안 취약점을 찾기 위한 프로그램 자동 분석 방법을 제안한다. 제안 방법은 문서, 멀티미디어 등 입력 값에 의해 발생되는 소프트웨어의 보안에 취약한 버그를 찾는 것을 목표로 한다. 먼저, 동적 오염 분석을 통해 입력 데이터가 취약 코드 지점까지 전파되는 과정을 추적하고 입력데이터 전파와 관련이 있는 명령어를 추출한다. 추출된 연관 명렁어를 수식화하고 이를 SMT 해석기를 이용하여 보안 취약점이 발생할 수 있는 입력 값을 찾는다. 제안 방법을 통해 아래아 한글, 곰 플레이어에서 크래시가 발생할 수 있는 입력값과 취약 코드 6개를 찾았다.

• 한국지진공학회논문집
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• 제18권4호
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• pp.171-180
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• 2014

Since the execution of structural design by professional structural engineers is not mandatory for small-size buildings in Korea, structural design is conducted by architects or contractors resulting in concern about the seismic safety of the buildings. Therefore, the Korean Structural Engineers Association proposed dedicated structural design criteria in 2012. The criteria were developed based on a deterministic approach in which the structural members are designed only with information of story and span length of the buildings and without structural analyses. However, due to the short time devoted to their development, these criteria miss satisfactory basis and do not deal with structural walls popularly used in Korea. Accordingly, the Ministry of Land, Infrastructure and Transport launched a research on the 'development of structural performance enhancement technologies for small-size buildings against earthquakes and climate changes'.. As part of this research, this paper intends to establish direction for the preparation of deterministic structural design guidelines for seismic safety of domestic small-size reinforced concrete buildings. To that goal, a typical plan of these buildings is selected considering frames only and frames plus walls, and then design is conducted by changing the number of stories and span length. Next, the seismic performance is analyzed by nonlinear static pushover analysis. The results show that the structural design guidelines should be developed by classifying frames only and frames plus walls. The size and reinforcement of structural elements should be provided in the middle level of the current Korean Building Code and criteria for small buildings by considering story and span length for buildings with frames only, and determined by considering the shape and location of walls and the story and span length as well for buildings with frames plus walls. It is recommended that the design of walls should be conducted by reducing the amount of walls along with symmetrically located walls.

• 정보보호학회논문지
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• 제25권3호
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• pp.573-583
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• 2015

앰캐시(Amcache.hve) 파일은 프로그램 호환성 관리자(Program Compatibility Assistant)와 관련된 레지스트리 하이브 파일로 응용 프로그램의 실행정보를 저장한다. 이 파일을 통해서 응용 프로그램의 실행경로, 최초 실행시간을 확인할 수 있을 뿐 아니라, 삭제시간까지 추정할 수 있다. 응용 프로그램의 최초 설치시간 및 삭제시간까지 확인할 수 있기 때문에 프리패치(Prefetch) 파일, 아이콘캐시(Iconcache.db) 파일 분석과 병행하면 응용 프로그램의 전체적인 타임라인을 구성할 수 있다. 또한, 앰캐시 파일은 안티포렌식 프로그램, 포터블 프로그램 및 외장저장장치 흔적을 기록하고 있어 디지털 포렌식 관점에서 중요한 아티팩트이다. 본 논문에서는 앰캐시 파일의 특성과 응용 프로그램 삭제시간 추정 등 디지털 포렌식 기술로서의 활용방안을 제시한다.

• 한국정보처리학회논문지
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• 제6권9호
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• pp.2384-2392
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• 1999

프로그램에서 요류가 발생되었을 때 프로그래머는 어떤 시험 사례(test case)를 통해 프로그램을 분석한다. 이처럼 현재 입력 값에 영향을 끼치는 모든 명령문들에 관련된 동적 슬라이싱(dynamic slicing)과 이를 구현하는 기술은 실제 테스팅 및 디버깅 분야에서 매우 중요하다고 할 것이다. 지금까지의 동적 슬라이싱은 슬라이싱 기준 변수가 1개 일 때의 경우에 대해서만 연구해 왔다. 그러나, 실제적인 테스팅 및 디버깅 분야에서는 슬라이싱 기준이 되는 변수가 2개 이상인 경우가 아주 많이 발생한다. 따라서 슬라이싱 기준 변수가 n 개 일 때 동적 프로그램 슬라이스(dynamic program slices)를 만드는 알고리즘을 제시하였고 프로그래밍 언어를 사용하여 동적 프로그램 슬라이싱 알고리즘을 프로그래밍한 뒤 예제 프로그램을 적용시켜 구현하였다. 구현 결과는 실행 이력에 대한 마킹 테이블(marking table)과 동적 종속 그래프로 나타내었다. 그리고, 본 논문에서 제시한 다중기준변수 동적 슬라이스 생성을 위한 마킹 알고리즘이 기존의 단일기준변수 기법보다 실제적인 테스팅 환경에서 더 우수함을 보였다.

• 정보처리학회논문지C
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• 제9C권2호
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• pp.149-156
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• 2002

프로그램 내 바이러스 코드 패턴을 탐색하는 현재의 백신 프로그램은 암호화 바이러스나, 다형성 바이러스를 탐지하는 데 어려움이 있다. 다형성 바이러스는 암호를 해제하는 코드 부분이 감염된 때마다 변형된다. 그래서, 이 바이러스를 탐지하기 위해서는 바이러스 본체를 해제하는 암호해제 코드의 행동을 추적해보아야 하며, 코드 분석시 많은 시간이 소요되는 것이 일반적이다. 특히, 바이러스 제작자가 바이러스 암호 해제 코드의 반복 실행 수를 늘려 놓았다면 기존의 방식으로는 이를 발견하기 어렵다. 본 논문에서는 이러한 다형성 바이러스를 탐지하기 위해서 개선된 알고리즘을 이용한 에뮬레이터를 제안한다. 이론 이용하여 다형성 바이러스를 탐지해본 결과, 기존의 에뮬레이터에 비해 다형성 바이러스 진단율이 약 2%정도 향상되었다. 또한, 제안된 다형성 바이러스 진단 시스템은 MS-Windows 뿐만 아니라 Linux 등 Unix 계열 플랫폼에서도 동작할 수 있다는 장점이 있다.

• Steel and Composite Structures
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• 제25권6호
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• pp.663-670
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• 2017

The problem of layup optimization of the composite laminates involves a very complex multidimensional solution space which is usually non-exhaustively explored using different heuristic computational methods such as genetic algorithms (GA). To ensure the convergence to the global optimum of the applied heuristic during the optimization process it is necessary to evaluate a lot of layup configurations. As a consequence the analysis of an individual layup configuration should be fast enough to maintain the convergence time range to an acceptable level. On the other hand the mechanical behavior analysis of composite laminates for any geometry and boundary condition is very convoluted and is performed by computational expensive numerical tools such as finite element analysis (FEA). In this respect some studies propose very fast FEA models used in layup optimization. However, the lower bound of the execution time of FEA models is determined by the global linear system solving which in some complex applications can be unacceptable. Moreover, in some situation it may be highly preferred to decrease the optimization time with the cost of a small reduction in the analysis accuracy. In this paper we explore some machine learning techniques in order to estimate the failure of a layup configuration. The estimated response can be qualitative (the configuration fails or not) or quantitative (the value of the failure factor). The procedure consists of generating a population of random observations (configurations) spread across solution space and evaluating using a FEA model. The machine learning method is then trained using this population and the trained model is then used to estimate failure in the optimization process. The results obtained are very promising as illustrated with an example where the misclassification rate of the qualitative response is smaller than 2%.

• 한국안전학회지
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• 제36권1호
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• pp.44-49
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• 2021

Domestic industrial accidents continue to increase, with 2,142 deaths in 2018, up by 185 (9.5%) from 1,957 deaths in 2017. Industrial accidents that cause loss of human lives pose a serious risk to businesses because of the strengthening of safety regulations and the changing public perception of social responsibility. Accordingly, to prevent industrial accidents, companies regularly conduct onsite safety activities and conduct education and training to raise awareness among employees. However, many such corporate activities are not conducted voluntarily and practically by employees but mostly by formal implementation. To discontinue this customary and passive behavior of employees and establish a mature safety culture, strengthening the execution power of safety management at the site is of paramount importance, and to this end, we aim to utilize the safety practice index (SPI). In this study, the SPI calculated on the basis of the results of the 2018 and 2019 risk management and safety activities of a site was compared with the reported safety accidents. The results confirmed that the SPI index can be used as a valid indicator for safety activities for accident prevention, such as strengthening leadership and safety policies to grade and manage safety management levels for a certain period of time or by a department or to convert weaknesses into strengths.

• 시스템엔지니어링학술지
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• 제18권2호
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• pp.58-74
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• 2022

Deterministic accident analysis plays a central role in the nuclear power plant (NPP) safety evaluation and licensing process. Traditionally the conservative approach opted for the point kinetics model, expressing the reactor core parameters in the form of reactivity and power tables. However, with the current advances in computational power, high fidelity multi-physics simulations using real-time code coupling, can provide more detailed core behavior and hence more realistic plant's response. This is particularly relevant for transients where the core is undergoing reactivity anomalies and uneven power distributions with strong feedback mechanisms, such as reactivity initiated accidents (RIAs). This work addresses a RIA, specifically a control element assembly (CEA) withdrawal at power, using the multi-physics analysis tool RELAP5/MOD 3.4/3DKIN. The thermal-hydraulics (TH) code, RELAP5, is internally coupled with the nodal kinetics (NK) code, 3DKIN, and both codes exchange relevant data to model the nuclear power plant (NPP) response as the CEA is withdrawn from the core. The coupled model is more representative of the complex interactions between the thermal-hydraulics and neutronics; therefore the results obtained using a multi-physics simulation provide a larger safety margin and hence more operational flexibility compared to those of the point kinetics model reported in the safety analysis report for APR1400. The systems engineering approach is used to guide the development of the work ensuring a systematic and more efficient execution.

• 대한치위생과학회지
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• 제5권1호
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• pp.21-27
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• 2022

Background: This study was conducted to analyze the time for re-detection of bacteria after surface disinfection using wet wipes, isopropyl alcohol, and benzalkonium chloride antibacterial tissue and provide standards for re-execution of surface disinfection with wet and antibacterial tissues. Methods: Seven laptops were wiped with wet tissue and isopropyl alcohol and benzalkonium chloride antibacterial tissues. Test areas were rubbed with a sterile cotton swab at baseline and after 30, 60, and 120 min. After plating on a tryptic soy agar medium, the number of colonies was counted by culturing at 36.5℃ for 24 h. Results: The average number of bacterial colonies was 5.85 ± 4.33 before isopropyl alcohol wiping and nil after wiping. The average number of bacterial colonies was 12.28 ± 14.67 benzalkonium chloride wiping and nil after wiping. Before wiping with wet wipes, the average number of bacterial colonies on laptop surfaces was 3.42 ± 5.22. Bacteria decreased after wiping with wet wipes but increased again over time. Conclusions: Wet wipes can temporarily reduce bacteria but are unsuitable for removing bacteria.

• International Journal of Computer Science & Network Security
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• 제22권1호
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• pp.241-247
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• 2022

This study examines teachers' implementation of strategies to modify the aggressive behavior of students with intellectual disabilities in Saudi Arabia, to determine the obstacles to their real-world execution. In addition, it presents potential approaches to overcome the obstacles to implementing strategies with this group of students. The research employed a qualitative design using semi-structured interviews as a data collection tool and applied a thematic analysis. The study population comprised 35 teachers of students with intellectual disabilities and the study sample numbered six teachers. The interviews were conducted via different methods: three by phone, two face-to face, and one using the Zoom platform. The results revealed inadequate understanding among teachers of intellectual disability and behaviour modification strategies, and this affected their capacity to develop plans that were compatible with the needs of students with intellectual disability. The findings also identified multiple obstacles that impede teachers' implementation of strategies to modify aggressive behaviour among students with intellectual disabilities; the most important being the lack of input from a psychological specialist when developing programs to modify aggressive behaviour. In general, it is apparent that programs for modifying aggressive behaviour are neither structured nor complementary, due to the scarcity of administrators with sufficient knowledge and familiarity with the characteristics and personalities of students with intellectual disabilities. This study presents several recommendations, the most important of which is that teachers of students with intellectual disability should develop themselves through training courses to enable them to deal with these students and create treatment plans that include strategies and clear steps to modify the aggressive behaviour of students with intellectual disabilities. To support teachers, it is also necessary to remove the obstacles facing education centres by providing financial support to create an environment in which they can access the required devices and equipment in their classes.