• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.514-518
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• 2003

In this paper, we investigate three dimensional optimal evasive maneuver patterns for air-to-surface attack missiles against proportionally navigated anti-air defense missiles. Interception error of the defense missile can be generated by evasive maneuver of the attack missile during the time of flight for which the defense missile intercepts the attack missile. Time varying weighted sum of the inverse of these interception errors forms a performance index to be minimized. Direct parameter optimization technique using CFSQP is adopted to get the attack missile's optimal evasive maneuver patterns according to parameter changes of both the attack missile and the defense missile such as maneuver limit and time constant of autopilot approximated by the 1st order lag system. The overall shape of resultant optimal evasive maneuver to enhance the survivability of air-to-surface missiles against proportionally navigated anti-air missiles is a kind of deformed barrel roll.

• 설비공학논문집
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• 제20권4호
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• pp.252-259
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• 2008

The purpose of this study is to estimate the movement of microbial contaminant caused by bio-attack using bio-agent such as bacillus anthracis for preventing contaminant diffusion. multizone simulation was carried out in the case of three types of bio-attack scenario in the government building. Simulation results show that severe contaminant diffusion is brought about in all cases of bio-attack scenario in one hour, though pollution boundaries have different mode according to bio-attack scenarios. Simulation results also show that immune building technology such as filter and UVGI technology gives us powerful alternatives to meet the emergent situation caused by unexpected bio-attack.

• 한국화재소방학회논문지
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• 제23권2호
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• pp.96-100
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• 2009

우리나라는 최근 숲이 우거져 있어 산불이 발생하면 대형화 위험성이 증대하고, 인력접근이 제한되어 항공기에 의한 진화율이 90% 이상이 된다. 그러므로 항공기 특히 헬기의 산불진화 활용성은 점차 증대 될 전망이다. 아울러 산불진화의 전 과정에 있어서 헬기 물 살포 기술은 안전한 헬기운항과 효율적인 산불진화의 성공요인으로서 특히, 표준화된 물 살포 기술은 매우 필요하다. 그러나 아직 헬기 물 살포 기술이 표준화 되지 않으므로 인하여 산불진화의 효율성과 안전성이 떨어지고 있다. 따라서 본 연구에서는 산불 현장 공중진화 경험을 바탕으로 11개의 헬기 물 살포 유형을 제안하였다.

• 한국정밀공학회지
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• 제4권1호
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• pp.42-52
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• 1987

Experimental investigation on the characteristics of the air flow around a square prism located in a uniform flow with various angles of attack was carried out. Experimental results were obtained for the angle of attack from 0 .deg. to 45 .deg. and for Reynolds No. from $2.6{\times}^4$to $12.8^4$. Seperation and reattachment was occurred on the forward face (face AB). Reattachment phenomenon was not developed in the range of attack angle lower 13 .deg. . But, for the range, 13 .deg. .approx. 35 .deg. , the reattachment developed and its position was moved forward the angle of attack increases. Pressure distributions on the reattachment face has a maxium at the reattachment point and a minimum at the separation point. Pressurea on two back faces are nearly symmetric in spite of the changes of the angle of attack and are influenced by the turbulence in rearward flow field.

• 한국콘텐츠학회논문지
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• 제8권6호
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• pp.54-65
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• 2008

무선 네트워크 환경에서 DDoS 공격이 수행될 경우 기존 유선 네트워크 환경보다 공격 패턴에 대한 탐지 및 공격지 역추적이 어렵다는 문제점을 보인다. 특히 무선 네트워크 환경에서는 사용자 인증 공격 및 패킷 스니핑 공격에 취약점을 보이고 있어 이에 대한 대응 기술이 연구되어야 한다. 최근 유무선 라우팅 기능과 함께 VoIP 통신 기능 등을 통합하여 지원하는 Integrated Access Device(IAD)가 개발되어 널리 배포되며 기존의 AP 기능을 대체하고 있다. 따라서 IAD 기반 무선 네트워크 환경에서도 유무선 트래픽에 대한 분류와 실시간 공격 탐지 기능이 제공되어야 한다. 본 연구에서는 AirSensor를 이용하여 IAD에 접속한 무선 네트워크 클라이언트 정보를 수집하며 무선 클라이언트의 공격 패킷에 대해 사전 차단 기능을 수행하도록 하였다. 또한 IAD에 수신된 패킷에 대해 W-TMS 시스템과 연동하여 DDoS 공격 트래픽을 판단하도록 하였고 이를 직접 차단하여 안정적으로 IAD 기반 무선 네트워크 서비스를 이용할 수 있도록 하였다.

• 고신대학교 의과대학 학술지
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• 제33권2호
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• pp.171-180
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• 2018

Objectives: We investigated whether asthma attacks in asthmatic children were caused by short-term exposure to particulate $matter(PM)_{2.5}$. Methods: Subjects were 411 patients who received inhalation therapy in National Fukuoka Hospital, from March to May 2013. All subjects were outpatients. We surveyed the air quality measurement results in the stations closest to the address of the patients. Data were used from the City of Fukuoka website data on air pollution. We carried out a case-crossover study and compared $PM_{2.5}$ concentration between 7 days after asthma attack occurred and the day asthma attack occurred and 1, 2 and 3 days before asthma attack occurred. Results: Highest hourly concentration of the day (OR 1.013, 95%CI 1.000-1.025) showed a significant association with 1 day before $PM_{2.5}$ concentration statistically. And 0-1 year-old infants were more vulnerable to the highest concentration of 1 day before $PM_{2.5}$ concentration(P < 0.05). Average concentration of $NO_2$ and $O_3$ and asthma attack also showed a significant association. Conclusions: Maximal daily $PM_{2.5}$ concentrations within 24 hours prior to the attack affect asthma exacerbation. 0-1 year-old infants are particularly vulnerable to $PM_{2.5}$ concentration. Asthma exacerbation is aggravated by $NO_2$ and $O_3$ concentration on the day of the asthma attack.

• 한국군사과학기술학회지
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• 제12권3호
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• pp.272-281
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• 2009

In this paper, three-dimensional optimal evasive maneuver patterns for air-to-surface attack missiles against proportionally navigated anti-air defense missiles were investigated. An interception error of the defense missile is produced by an evasive maneuver of the attack missile. It is assumed that the defense missiles are continuously launched during the flight of attack missile. The performance index to be minimized is then defined as the negative square integral of the interception errors. The direct parameter optimization technique based on SQP and a co-evolution method based on the augmented Lagrangian formulation are adopted to get the attack missile's optimal evasive maneuver patterns. The overall shape of the resultant optimal evasive maneuver is represented as a deformed barrel-roll.

• EDISON SW 활용 경진대회 논문집
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• 제6회(2016년)
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• pp.19-22
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• 2016

Leading edge thrust is generally caused by passing air flow from lower to upper surface and it is required to have sufficient angle of attack for notable leading edge thrust. To produce leading edge thrust at low angle of attack, utilizing expansion wave accompanying low pressure is able to be a solution. Fore structure changes the direction of flow, and this flow passes the projected edge. As a result, from a perspective of the edge, it is able to have high angle of attack, and artificial expansion wave is generated. This concept shows 9.48% increase of L/D in inviscid flow, at Mach number 1.3 and angle of attack $1^{\circ}$ in maximum, and this model shows the 3.98% of increasement at angle of attack $2^{\circ}$. Although advantage of the artificial expansion wave decreased as angle of attack increase, it shows the possibility of aerodynamical improvement with artificial expansion wave.

• Journal of Mechanical Science and Technology
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• 제17권6호
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• pp.914-924
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• 2003

The interaction and breakdown of vortices over the Leading Edge Extension (LEX) - Delta wing configuration has been investigated through wing-surface pressure measurements, the off-surface flow visualization, and 5-hole probe measurements of the wing wake section. The description focused on analyzing the interaction and the breakdown of vortices depending on the angle of attack and the sideslip angle. The Effect of angle of attack and sideslip angle on the aerodynamic load characteristics of the model is also presented. The sideslip angle was found to be a very influential parameter of the vortex flow over the LEX-delta wing configuration. The introduction of LEX vortex stabilized the vortex flow, and delayed the vortex breakdown up to a higher angle of attack. The vortex interaction and breakdown was promoted on the windward side, whereas it was suppressed on the leeward side.

• 인터넷정보학회논문지
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• 제25권3호
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• pp.1-8
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• 2024

As the Internet of Things (IoT) has gained significant prominence in our daily lives, most IoT devices rely on over-the-air technology to automatically update firmware or software remotely via the network connection to relieve the burden of manual updates by users. And preserving security for OTA interface is one of the main requirements to defend against potential threats. This paper presents a simulation of an attack scenario on the commoditized System-on-a-chip, ESP32 chip, utilized for drones during their OTA update process. We demonstrate three types of attacks, WiFi cracking, ARP spoofing, and TCP SYN flooding techniques and postpone the OTA update procedure on an ESP32 Drone. As in this scenario, unpatched IoT devices can be vulnerable to a variety of potential threats. Additionally, we review the chip to obtain traces of attacks from a forensics perspective and acquire memory forensic artifacts to indicate the SYN flooding attack.