• 한국군사과학기술학회지
• /
• 제19권2호
• /
• pp.236-243
• /
• 2016

This paper presents a threat list acquisition method in an engagement area using the support vector machines (SVM). The proposed method consists of track creation, track estimation, track feature extraction, and threat list classification. To classify the threat track robustly, dynamic track estimation and pattern recognition algorithms are used. Dynamic tracks are estimated accurately by approximating a track movement using position, velocity and time. After track estimation, track features are extracted from the track information, and used to classify threat list. Experimental results showed that the threat list acquisition method in the engagement area achieved about 95 % accuracy rate for whole test tracks when using the SVM classifier. In case of improving the real-time process through further studies, it can be expected to apply the fire control systems.

• 항공우주시스템공학회지
• /
• 제15권2호
• /
• pp.36-44
• /
• 2021

Unmanned aerial vehicles (UAVs) are increasingly needed as they can replace manned aircrafts in dangerous military missions. However, because of their low autonomy, current UAVs can execute missions only under continuous operator control. To overcome this limitation, higher autonomy levels of UAVs based on autonomous situational awareness is required. In this paper, we propose an autonomous situational awareness software consisting of situation awareness management, threat recognition, threat identification, and threat space analysis to detect dynamic situational change by external threats. We implemented the proposed software in real mission computer hardware and evaluated the performance of situational awareness toward dynamic radar threats in flight simulations.

• 한국산업정보학회논문지
• /
• 제22권2호
• /
• pp.15-25
• /
• 2017

A System can be more Dependable from some types of Threats if the Dependability Level Against the Threat on the System is Increased. However, The Dependability-performance Tradeoff should be Considered because the Increased Dependability may Degrade the Performance of the System. Therefore, it is Efficient to Temporally Increase the Dependability Level to High only when an Threat is Predicted on the System in a Short time while Maintaining the Level in Low or mid in Normal Situations. In this Paper, we Present a Threat Prevention Strategy for a Networked Node by Dynamically Changing the Dependability Level According to the Threat Situation on its Logically/physically Neighboring Nodes. As case Studies, we Employ our Strategy to an Internet Server Against TCP SYN Flood Attacks and to a Checkpoint and Rollback System Against Transient Faults. Our Performance Analysis Shows that our Strategy can Effectively Relieve the Damage of the Failure without Serious Performance Degradation.

• 감성과학
• /
• 제25권1호
• /
• pp.21-28
• /
• 2022

People differ greatly in their capacity to persist in the face of challenges. Despite significant research, relatively little is known about cognitive factors that might be involved in perseverance. Building upon human threat-management mechanism, we predicted that perseverant people would be characterized by reduced sensitivity (i.e., longer detection latency) to threat cues. Our data from 5,898 job applicants showed that highly perseverant individuals required more time to correctly identify anger in faces, regardless of stimulus type (dynamic or static computer-morphed faces). Such individual differences were not observed in response to other facial expressions (happiness, sadness), and the effect was independent of gender, dispositional anxiety, or conscientiousness. Discussions were centered on the potential role of threat sensitivity in effortful pursuit of goals.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제14권8호
• /
• pp.3420-3436
• /
• 2020

Due to the increasing number of malicious software (also known as malware), methods for sharing threat information are being studied by various organizations. The Malware Attribute Enumeration and Characterization (MAEC) format of malware is created by analysts, converted to Structured Threat Information Expression (STIX), and distributed by using Trusted Automated eXchange of Indicator Information (TAXII) protocol. Currently, when sharing malware analysis results, analysts have to manually input them into MAEC. Not many analysis results are shared publicly. In this paper, we propose an automated MAEC conversion technique for sharing analysis results of malicious Android applications. Upon continuous research and study of various static and dynamic analysis techniques of Android Applications, we developed a conversion tool by classifying parts that can be converted automatically through MAEC standard analysis, and parts that can be entered manually by analysts. Also using MAEC-to-STIX conversion, we have discovered that the MAEC file can be converted into STIX. Although other researches have been conducted on automatic conversion techniques of MAEC, they were limited to Windows and Linux only. In further verification of the conversion rate, we confirmed that analysts could improve the efficiency of analysis and establish a faster sharing system to cope with various Android malware using our proposed technique.

• 정보과학회 논문지
• /
• 제41권10호
• /
• pp.859-869
• /
• 2014

최근 몇 년 동안, 난독화 기술은 악성 코드를 보호하기 위해 악용되어 큰 위협이 되고 있다. 특히, 가상 머신 기반으로 난독화된 악성 코드의 경우, 원본 프로그램이 직접적으로 드러나지 않고 가상머신의 의미와 원본 프로그램의 의미가 함께 수행되므로 분석하기 어렵다. 이러한 위협에 대응하기 위하여, 가상 머신 기반으로 난독화된 프로그램을 분석하는 동적 분석 기반의 프레임워크를 제안한다. 첫째, 난독화된 실행파일의 동적 실행 트레이스를 추출한다. 둘째, 동적 실행 트레이스를 중간언어로 변환하고 동적 제어 흐름 그래프를 이용하여 가상 머신의 구조를 추출한다. 결과적으로, 추출된 가상 머신 구조를 이용하여 원본 프로그램의 의미를 추출한다. 본 논문은 최신 상용 난독화 도구로 난독화된 실행파일에서 원본 프로그램을 추측할 수 있는 방안을 제시한다. 개발된 도구는 가상 머신 기반으로 난독화된 프로그램을 이해하고 프로그램 분석 기법을 적용하는 데 활용될 수 있으며 추출된 원본 프로그램의 요약 의미를 이용하여 추가적인 분석을 적용할 수 있을 것으로 기대한다.

• 정보처리학회논문지D
• /
• 제17D권2호
• /
• pp.167-174
• /
• 2010

비밀번호를 입력하는 과정에서 가장 큰 보안 위협은 비밀번호를 훔쳐보는 것이다. 비밀번호 훔쳐보기는 비밀번호를 입력하는 과정을 옆에서 지켜보고 비밀번호를 획득하려고 하는 행위로서 비밀번호를 획득하는 가장 전통적인 방법이며 강력한 보안 위협이다. 본 논문에서는 인지심리학에 기초한 비밀번호 훔쳐보기로부터 안전한 기술인 역동 인증 체계(DAS)라 불리는 비밀번호 입력 기술을 제안하였다. 그리고 제안한 역동 인증 체계의 비밀번호 훔쳐보기에 대한 안전성을 직관적인 관점, 훔쳐보기 실험, 이론적인 분석으로 구분하여 검증하였다. 비밀번호 훔쳐보기로부터 안정성이 입증된 역동 인증 체계를 내장시킨 비밀번호 입력기를 설계하여 구현하였다. 구현한 비밀번호 입력기는 일반 패스워드 입력방식 보다 훔쳐보기 공격자의 비밀번호 획득 확률을 현저하게 낮출 수 있으므로 은행에서 운영하는 금융자동화기기에 적용 및 운영되기에 적합한 것으로 평가를 받아 금융기관에서 도입하여 활용되고 있다.

• 정보보호학회논문지
• /
• 제21권3호
• /
• pp.67-74
• /
• 2011

본 논문에서는 복잡하고 변형된 공격을 탐지할 수 있는 사이버 공격 모델을 위해서 공격 시나리오를 유연하게 표현할 수 있는 능동적인 사이버 공격 트리를 제안하였다. 공격 트리는 네트워크 시스템에 대한 다양한 공격에 대해 보안 대책을 수립할 수 있도록 체계적이고 조직적인 해결책을 제시한다. 기존의 공격 트리는 정점 (${\nu}$), 엣지(${\varepsilon}$) 그리고 조합(${\theta}$)을 이용하여 공격 시나리오를 표현할 수 있다. 그러나 제한적인 애트리뷰트를 인해서 복잡하고 변형된 공격을 표현하기에는 한계가 있다. 우리는 공격 트리 애트리뷰트에 조합 요소와 위협발생확률을 추가하여 기존에 공격 트리가 갖고 있던 한계점을 해결하였다. 우선 조합요소를 강화하여 공격 순서의 모호성을 줄였으며 변형된 공격 표현의 유연성을 향상시켰다. 위협발생확률을 추가하여 자식노드부터 부모노드까지의 공격단계별 위험수준을 알 수 있게 하였다.

• Earthquakes and Structures
• /
• 제21권6호
• /
• pp.601-612
• /
• 2021

The paper concerns the selection of a design accelerograms used for the slope stability assessment under earthquake excitation. The aim is to experimentally verify the Arias Intensity as an indicator of the excitation threat to the slope stability. A simple dynamic system consisting of a rigid block on a rigid inclined plane subjected to horizontal excitation is adopted as a slope model. Strong ground motions recorded during earthquakes are reproduced on a shaking table. The permanent displacement of the block serves as a slope stability indicator. Original research stand allows us to analyse not only the relative displacement but also the acceleration time history of the block. The experiments demonstrate that the Arias Intensity of the accelerogram is a good indicator of excitation threat to the stability of the slope. The numerical analyses conducted using the experimentally verified extended Newmark's method indicate that both the Arias Intensity and the peak velocity of the excitation are good indicators of the impact of dynamic excitation on the dam's stability. The selection can be refined using complementary information, which is the dominant frequency and duration of the strong motion phase of the excitation, respectively.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2003년도 춘계학술대회
• /
• pp.1262-1269
• /
• 2003

In structural optimization, static loads are generally utilized although real external forces are dynamic. Dynamic loads have been considered in only small-scale problems. Recently, an algorithm for dynamic response optimization using transformation of dynamic loads into equivalent static loads has been proposed. The transformation is conducted to match the displacement fields from dynamic and static analyses. The algorithm can be applied to large-scale problems. However, the application has been limited to size optimization. The present study applies the algorithm to shape optimization. Because the number of degrees of freedom of finite element models is usually very large in shape optimization, it is difficult to conduct dynamic response optimization with the conventional methods that directly threat dynamic response in the time domain. The optimization process is carried out via interfacing an optimization system and an analysis system for structural dynamics. Various examples are solved to verify the algorithm. The results are compared to the results from static loads. It is found that the algorithm using static loads transformed from dynamic loads based on displacement is valid even for very large-scale problems such as shape optimization.