• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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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.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.4
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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.

• Fire Science and Engineering
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• v.23 no.2
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• pp.96-100
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• 2009

Because of dense forests and restriction of approaching for fire fighters, forest fire is easy to be a larger fire in Korea. For this result, the air attack was about 90% of extinguishing, so the application of aircrafts, especially helicopters, will be increased gradually. In the all process of forest fire attack, the method of heli-scattering water was the chief element of success of efficient forest fire attack and safe flight. Therefore, a standardized method of heli-scattering water was required. However, as it was not already standardized, a efficiency and safety of fire fighting have been decreased. In this study, we suggest a 11 patterns of methods for scatterling water based on a actual experience of air attack.

• Journal of the Korean Society for Precision Engineering
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• v.4 no.1
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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.

• The Journal of the Korea Contents Association
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• v.8 no.6
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• pp.54-65
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• 2008

When DDoS attack is achieved, malicious host discovering is more difficult on wireless network than existing wired network environment. Specially, because wireless network is weak on wireless user authentication attack and packet spoofing attack, advanced technology should be studied in reply. Integrated Access Device (IAD) that support VoIP communication facility etc with wireless routing function recently is developed and is distributed widely. IAD is alternating facility that is offered in existent AP. Therefore, advanced traffic classification function and real time attack detection function should be offered in IAD on wireless network environment. System that is presented in this research collects client information of wireless network that connect to IAD using AirSensor. And proposed mechanism also offers function that collects the wireless client's attack packet to monitoring its legality. Also the proposed mechanism classifies and detect the attack packet with W-TMS system that was received to IAD. As a result, it was possible for us to use IAD on wireless network service stably.

• Kosin Medical Journal
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• v.33 no.2
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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.

• Journal of the Korea Institute of Military Science and Technology
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• v.12 no.3
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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.

• Proceeding of EDISON Challenge
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• 2016.11a
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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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• v.17 no.6
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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.

• Journal of Internet Computing and Services
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• v.25 no.3
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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.