• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권5호
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• pp.967-979
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• 2013

Now a day, Wireless Sensor Networks (WSNs) are being widely used in different areas one of which is healthcare services. A wireless medical sensor network senses patient's vital physiological signs through medical sensor-nodes deployed on patient's body area; and transmits these signals to devices of registered medical professionals. These sensor-nodes have low computational power and limited storage capacity. Moreover, the wireless nature of technology attracts malicious minds. Thus, proper user authentication is a prime concern before granting access to patient's sensitive and private data. Recently, P. Kumar et al. claimed to propose a strong authentication protocol for healthcare using Wireless Medical Sensor Networks (WMSN). However, we find that P. Kumar et al.'s scheme is flawed with a number of security pitfalls. Information stored inside smart card, if extracted, is enough to deceive a valid user. Adversary can not only access patient's physiological data on behalf of a valid user without knowing actual password, can also send fake/irrelevant information about patient by playing role of medical sensor-node. Besides, adversary can guess a user's password and is able to compute the session key shared between user and medical sensor-nodes. Thus, the scheme looses message confidentiality. Additionally, the scheme fails to resist insider attack and lacks user anonymity.

• 대한한의학원전학회지
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• 제27권3호
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• pp.33-46
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• 2014

Objectives : Sosihotang is a typical prescription in Sang Han Lun. And the alternate chills and fever is a Sosihotang's typical symptom. Therefore I will study of how the syndrome of Sosihotang's alternate chills and fever caused. Methods : Examine the claims of the syndrome of Sosihotang's alternate chills and fever in Sang Han Lun. The scholar's claims are not all same. Thus, I analysis the claims of many scholars. Results : The syndrome of Sosihotang has two mechanisms. The move of defensive Gi(衛氣) can explain the occurrence of alternate chills and fever. If the defense Gi enter inside the body, it struggle with pathogenic Gi, the fever is occurred. On the contrary to this, if the defense Gi exits the body the chills occurs because of the lack of defense Gi. Conclusions : The syndrome of Sosihotang could be taken ill by tranmission or direct attack of exogenous pathogenic factors(直中). Symptoms chills and fever occurs due to the entrance and exit of defensive Gi.

• 한국시뮬레이션학회논문지
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• 제17권3호
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• pp.45-51
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• 2008

개전 초,적군은 다양한 화력지원수단을 이용하여 아군의 핵심시설 파괴를 기도할 것이다. 이러한 화력지원수단 중 포병은 가장 큰 비중을 차지하고 있다. 갱도포병은 생존성 측면에서 아군에 비해 월등한 우세를 점하고 있어 아군에게 큰 위협요소로 판단된다. 갱도포병을 타격하는 연구는 지금까지 군 내부의 연구를 통해서 발전해 왔다. 그러나 이러한 연구의 대부분이 정성적인 분석방법으로 이루어져 객관적이지 못하고 다양하지 못한 방법이라는 한계를 지니고 있다. 이에 본 연구에서는 아군이 생존성의 약점을 극복하기 위하여 갱도포병이 갱도 출구를 개방하고 사격을 개시하기 전에 타격하는데 초점을 맞추고 갱도 포병을 타격하기 위한 정량적인 분석 방법으로 DEVS를 이용한 시뮬레이션 연구를 수행하고자 한다.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 전기학술대회논문집
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• pp.1083-1090
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• 2005

Repeated ribs are used on heat exchange surfaces to promote turbulence and enhance convective heat transfer. Applications include fuel rods of gas-cooled nuclear reactors, inside cavities of turbine blades, and internal surfaces pipes used in heat exchangers. Despite the great number of literature papers, only few experimental data concern detailed distributions of friction factors and heat transfer coefficients in square channels varying the number of rough walls. This issue is tackled by investigating effects of different number of ribbed walls on heat transfer and friction characteristics in square channel. The rough wall have a 45$^{\circ}$ inclined square rib. Uniform heat flux is maintained on whole inner heat transfer channel area. The heat transfer coefficient and friction factor values increase with increasing the number of rough walls.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.795-800
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• 2000

A CCFL(Counter Current Flow Limit) test have been performed in narrow annular gaps with large diameter, because it has been confirmed that the CCFL phenomena affected the critical power in hemispherical narrow gap geometries from the SONATA(Simulation Of Naturally Arrested Thermal Attack)-IV (In-Vessel)/VISU(Visualization)-II experiments. The objectives of the CCFL experiments are to investigate the small gap sizes(1, 2mm) effect on CCFL under the large diameter condition and to confirm the findings of the VISU-II study that global dryout in hemispherical narrow gaps was induced by the CCFL. The test section was made of acrylic resin to allow visual observation on the two-phase flow behaviors inside annular gaps. It was observed from visualization that a part of water supplied was accumulated in the upper plenum and a significant increase in the differential pressure across the gap was occurred, which was the definition of the CCFL occurrence in this experimental study. From the experimental results in annular gap with large diameter it can be known that an increase in the differential pressure was not big at small air flow-rates. When the CCFL was occurred, the differential pressure across gaps was increased significantly and a water accumulated in the upper plenum. The occurrence of CCFL was correlated using the Wallis parameter.

• 동력기계공학회지
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• 제9권1호
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• pp.30-35
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• 2005

Repeated ribs are used on heat exchanger surfaces to promote turbulence and to enhance convective heat transfer. Applications include fuel rods of gas-cooled nuclear reactors, inside cavities of turbine blades, and internal surfaces pipes used in heat exchangers. Despite the great number of literature papers, only few experimental data concerns detailed distributions of friction factors and heat transfer coefficients in square channels varying the number of rough walls. This issue was tackled by investigating effects of different number of ribbed walls on heat transfer and friction characteristics in square channel. The rough wall had a $45^{\circ}$ inclined square rib. Uniform heat flux was maintained on the whole inner heat transfer channel area. The heat transfer coefficient and friction factor values increased with increasing the number of rough walls.

• 한국균학회소식:학술대회논문집
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• 한국균학회 2015년도 추계학술대회 및 정기총회
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• pp.18-18
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• 2015

Wilt disease in Oak trees occurs during summer season in Korea. Mass attack of trees by an ambrosia beetle (Platypus koryoensis) was the characteristic feature before appearance of the wilting symptoms. Raffaelea sp. caused the discoloration of xylem area called as wound heartwood. Raffaelea sp. was observed both on the body surfaces and inside the mycangia of the beetle Platypus sp. The scanning electron microscope (SEM) analysis showed that fungal spores were present within the wall of gallery and vessels that formed tyloses. The results revealed that the water movement in vessels was blocked as the fungus started to grow which caused the formation of tyloses thereby resulting wilt symptoms. We found that both female and male beetle Platypus sp. had fungi on their bodies and their large and small mycangia. This study confirmed that the fungus was transferred to oak trees by Platypus sp.

• 한국군사과학기술학회지
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• 제10권2호
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• pp.188-197
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• 2007

Active flow control, in the form of steady and unsteady momentum injection via jet blowing was studied. A jet was obtained by pressing a plenum inside the airfoil and ejecting flow out of a thin slot. The normal and drag forces were measured with leading edge or trailing edge blowing Jet and compared with the results obtained with no blowing. The blowing jet has been shown to improve the aerodynamic performance of the airfoil. The steady jet proved more effective than pulsating jet in these experimental conditions. Furthermore for the case of leading edge steady blowing jet, the alleviation of non-linearity in the normal force curve slope can be seen at higher angles of attack. No effective trailing edge jet was observed in this highly separated flow. This shows that the stall control is highly depends on the characteristics of the boundary layer near the jet slot.

• 융합보안논문지
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• 제13권1호
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• pp.79-86
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• 2013

본 연구는 최근 들어 DDoS 공격이 단순히 서비스를 방해하는 것에서 벗어나, 다양한 공격 기법을 혼합한 멀티벡터(Multi-Vector) 공격으로 발전하고 있다. 이러한 멀티벡터 공격은 DDoS 공격과 더불어 악성코드를 감염시켜, 내부 정보 유출 및 좀비PC를 만들어 DDoS 공격용에 활용될 경우에는 기존의 DDoS 공격 및 악성코드 감염에 대한 방어 전략으로는 한계점이 있다. 따라서 본 논문에서는 다양한 방법을 이용한 멀티벡터 공격을 효과적으로 방어하기 위한 Reverse Proxy Group과 PMS(Patch Management Server)를 제시하고자 한다.

• 정보보호학회논문지
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• 제24권6호
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• pp.1263-1269
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• 2014

상용제품에 종속적인 국방 사이버 방호체계 생태계는 APT(Advanced Persistent Threat) 등 지능화된 최근 사이버 공격양상에 더욱 취약할 수 있다. 일반무기체계는 대부분 특정 방위산업체가 양산한 관급제품으로 원천기술 등에 대한 보호가 가능하지만 사이버 방호체계는 대부분 상용제품으로 군을 공격하지 않고 산업체 공격을 통해 군 공격이 직 간접적으로 가능하다. 본 논문에서는 국방 사이버 방호체계를 구축해나가는 생태계에 있어서 적 공격의 가상 시나리오를 분석해보고, 이에 대한 취약성 및 위협성을 평가 및 검증하여 안전한 국방 사이버 방호체계 생태계 구축을 위한 기술적, 정책적 방안을 제시한다.