• 한국운동역학회지
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• 제27권1호
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• pp.1-7
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• 2017

Objective: The purpose of this study was to analyze the relationship between ground reaction force (GRF) and attack time according to the position of hand segments during counter attack in Kendo. Method: The participants consisted of 10 kendo athletes (mean age: $21.50{\pm}1.95yr$, mean height: $175.58{\pm}5.02cm$, mean body weight: $70.96{\pm}9.47kg$) who performed standard head strikes (A) and counter attack with a preferred hand position of +10 cm (B), 0 cm (C), and -10 cm (D). One force-plate (AMTI-OR-7., USA) was used to collect GRF data at a sample rate of 1,000 Hz. The variables analyzed were the attack time, medial-lateral GRF, anterior-posterior GRF (AP GRF), peak vertical force (PVF), and loading rate. Results: The total attack time was shorter in types A and C than in types C and D. The AP GRF, PVF, and loading rate had significantly higher forces in types C and D than in types A and C. The attack time (bilateral and unilateral leg support and total) was positively correlated with the GRF variables (vertical GRF and loading rate) during the counter attack in Kendo (r = 0.779 [$R^2=0.607$], p < 0.001). Conclusion: The positions of the hand segments can be changed by various conditions of the opponent in Kendo competitions; however, the position preferred by an individual can promote the successful ratio of the counter attack.

• 정보보호학회논문지
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• 제32권3호
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• pp.527-545
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• 2022

본 연구에서는 조직화된 공격 주체가 수행하는 APT 공격을 효과적으로 탐지하기 위하여, 공격체인을 구성하여 공격을 탐지하는 시스템을 구축하였다. 공격체인 기반 APT 공격 탐지 시스템은 다양한 호스트 및 네트워크 모니터링 도구에서 생성하는 이벤트를 수집하고 저장하는 '이벤트 수집 및 저장부', 이벤트로부터 MITRE ATT&CK^®에 정의된 공격기술 수준의 단위공격을 탐지하는 '단위공격 탐지부', 단위공격으로 생성된 이벤트로부터 Provenance Graph 기반의 인과관계 분석을 수행하여 공격체인을 구성하는 '공격체인 구성부'로 구성하였다. 시스템을 검증하기 위하여 테스트베드를 구축하고 MITRE ATT&CK Evaluation 프로그램에서 제공하는 모의공격 시나리오를 수행하였다. 실험 결과 모의공격 시나리오에 대해 공격체인이 효과적으로 구성되는 것을 확인하였다. 본 연구에서 구현한 시스템을 이용하면, 공격을 단편적인 부분으로 이해하기보다 공격의 진행 흐름 관점에서 이해하고 대응할 수 있을 것이다.

• 정보처리학회논문지:컴퓨터 및 통신 시스템
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• 제2권9호
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• pp.393-398
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• 2013

본 논문에서는 일차 전력 분석에 안전한 AES의 마스킹 기법을 분석할 수 있는 새로운 충돌쌍 공격을 제안한다. 제안하는 충돌쌍 공격은 기존 충돌쌍 공격의 단점인 선택 평문 공격의 단점을 극복하고 기지 평문 공격이 가능하도록 구성되어진다. 또한 제안하는 분석기법은 이차 전력분석보다 효율적이며 최근 제안된 충돌쌍 공격에 요구되는 파형 개수에 비해 약 1/27.5배의 파형만을 요구한다. 논문에 포함된 실험 결과들은 이러한 사실을 뒷받침한다. 본 논문에서는 또한 새로운 분석 기법과 함께 이 방법을 방어할 수 있는 간단한 대응방법을 소개하도록 한다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.465-471
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• 2000

The flow characteristics around an elliptic cylinder with axis ratio of AR=2 located near a flat plate were investigated experimentally to study the interaction between the cylinder wake and the turbulent boundary layer. The pressure distributions on the cylinder surface and on the flat plate were measured with varying the angle of attack of the cylinder. In addition, the velocity profiles of wake behind the cylinder were measured using a hot-wire anemometry As the angle of attack increases, the location of peak pressure on the windward and leeward surfaces of the cylinder moves toward the rear and front of the cylinder, respectively. At positive angles of attack, the position of the minimum pressure on the flat plate surface is moved downstream, but it is moved upstream at negative angles of attack. With increasing the angle of attack, the vortex shedding frequency is gradually decreased and the critical angel of attack exists in terms of the gap ratio. By installing the elliptic cylinder at negative angle of attack, the turbulent boundary layer over the flat plate is disturbed more than that at positive incidence. This may be attributed to the shift of separation point on the lower surface of the cylinder according to the direction of the angle of attack.

• 디지털산업정보학회논문지
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• 제6권4호
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• pp.117-130
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• 2010

Paper is on defense for so-called internet crisis, the attack of DDoS (Distributed Denial of Service) which was targeted to the central government ministries, financial sector, and portal sites of chief counties including Korea on June 7th, 2009 as its start. By conducting attack with various DDoS attacking methods in the lab environment and dividing networks targeted by the attack by layers, this paper records and analyzes the chief information for attack, destination information of packets, defense policy setting, and the flow of packet attack with the subjects of the networks separated. This study suggests CFC system using multiple firewalls applying defense policy corresponding to the target layer for ultimate attack and tests it according to the result of analyzing the attack packet information and its amount, log analysis, access recording port, and MAC and IT information, etc. by layers. This article is meaningful in that it analyzes the attack by layers, establishes firewall policy for protecting each layer, and secures accurate mechanism for detect and defense.

• 융합보안논문지
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• 제10권4호
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• pp.83-91
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• 2010

본 연구는 한반도내에서 발생 가능한 비대칭 전략으로서의 '사이버 기습공격'의 발생 가능성에 대해 분석하고 이에 대한 정책적 대책을 제시하기 위해 작성한 것이다. 최근 발생하고 있는 이란, 중국 등에서 발생한 'Stuxnet' 사이버 기습공격 피해 사례로 볼 때 만일 북한이 남한의 인프라 시설을 공격한다면 남한 사회에 큰 혼란과 피해를 줄 수 있을 것이다. 최근 발생한 연평도 기습도발 사건 이후 계속적인 도발 위협을 하고 있는 북한의 태도로 볼 때 Stuxnet과 같은 사이버공격을 감행할 개연성이 높기 때문에 이에 대한 정책적 대책을 제시하였다. 주요 대책은 1) 독립된 중앙집권적 정부통합조직 신설, 2) 특수대학 설립으로 사이버전 전문인력 양성, 3) 예산증액 및 전문인력 관리체계 개선이다.

• 디지털산업정보학회논문지
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• 제10권1호
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• pp.105-112
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• 2014

The utilization of Wireless Ad Hoc Network which can build easily network using wireless device in difficult situation to build network is very good. However, it has security threat element because it transfers data by only forwarding of wireless devices. The measures against this should be prepared because damage by especially routing attack can affect the entire network. It is hard to distinguish malicious node and normal node among nodes composing network and it is not easy also to detect routing attack and respond to this. In this paper, we propose new method which detect routing attack and can respond to this. The amount of traffic in all nodes is measured periodically to judge the presence or absence of attack node on the path set. The technique that hides inspection packet to suspected node and transmits is used in order to detect accurately attack node in the path occurred attack. The experiment is performed by comparing SRAODA and SEAODV technique to evaluate performance of the proposed technique and the excellent performance can be confirmed.

• 한국군사과학기술학회지
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• 제21권2호
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• pp.180-187
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• 2018

In this study, we develop a prediction method of cavity shape taking gravity effect and angle of attack of cavitator into consideration simultaneously. Logvinovich's theoretical formulas are superimposed to predict the change of cavity centerline due to both gravity effect and angle of attack of cavitator. It is found that as the angle of attack of cavitator increases, the gravity effect is weakened due to decrease in cavity volume, and even in case of the same angle of attack, cavity shape changes in different ways depending on whether the angle of attack of cavitator is positive or negative. We conclude that cavity shapes are largely affected by the angle of attack of cavitator, and the gravity effect and angle of attack of cavitator should be considered at the same time for the prediction of cavity shape.

• Advances in concrete construction
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• 제5권6호
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• pp.671-683
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• 2017

Commonly used concrete in general, consists of cement, fine aggregate, coarse aggregate and water. Natural river sand is the most commonly used material as fine aggregate in concrete. One of the important requirements of concrete is that it should be durable under certain conditions of exposure. The durability of concrete is defined as its ability to resist weathering action, chemical attack or any other process of deterioration. Durable concrete will retain its original form, quality and serviceability when exposed to its environment. Deterioration can occur in various forms such as alkali aggregate expansion, freeze-thaw expansion, salt scaling by de-icing salts, shrinkage, attack on the reinforcement due to carbonation, sulphate attack on exposure to ground water, sea water attack and corrosion caused by salts. Addition of admixtures may control these effects. In this paper, an attempt has been made to replace part of fine aggregate by tailing material and part of cement by fly ash to improve the durability of concrete. The various durability tests performed were chemical attack tests such as sulphate attack, chloride attack and acid attack test and water absorption test. The concrete blend with 35% Tailing Material (TM) in place of river sand and 20% Fly Ash (FA) in place of OPC, has exhibited higher durability characteristics.

• International Journal of Computer Science & Network Security
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• 제21권8호
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• pp.1-12
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• 2021

An operation of an organization is currently using a digital environment which opens to potential cyber-attacks. These phenomena become worst as the cyberattack landscape is changing rapidly. The impact of cyber-attacks varies depending on the scope of the organization and the value of assets that need to be protected. It is difficult to assess the damage to an organization from cyberattacks due to a lack of understanding of tools, metrics, and knowledge on the type of attacks and their impacts. Hence, this paper aims to identify domains and sub-domains of cyber-attack taxonomy to facilitate the understanding of cyber-attacks. Four phases are carried in this research: identify existing cyber-attack taxonomy, determine and classify domains and sub-domains of cyber-attack, and construct the enhanced cyber-attack taxonomy. The existing cyber-attack taxonomies are analyzed, domains and sub-domains are selected based on the focus and objectives of the research, and the proposed taxonomy named AVOIDITALS Cyber-attack Taxonomy is constructed. AVOIDITALS consists of 8 domains, 105 sub-domains, 142 sub-sub-domains, and 90 other sub-sub-domains that act as a guideline to assist administrators in determining cyber-attacks through cyber-attacks pattern identification that commonly occurred on digital infrastructure and provide the best prevention method to minimize impact. This research can be further developed in line with the emergence of new types and categories of current cyberattacks and the future.