• 한국IT서비스학회지
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• 제15권2호
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• pp.157-167
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• 2016

Task environment for enterprises and public institutions are moving into cyberspace-based environment and structing the LTE wireless network. The applications "App" operated in the LTE wireless network are mostly being developed with Android-based. But Android-based malwares are surging and they are the potential DDoS attacks. DDoS attack is a major information security threat and a means of cyber attacks. DDoS attacks are difficult to detect in advance and to defense effectively. To this end, a DMZ is set up in front of a network infrastructure and a particular server for defensive information security. Because There is the proliferation of mobile devices and apps, and the activation of android diversify DDoS attack methods. a DMZ is a limit to detect and to protect against DDoS attacks. This paper proposes an information security method to detect and Protect DDoS attacks from the terminal phase using a Preemptive military strategy concept. and then DDoS attack detection and protection app is implemented and proved its effectiveness by reducing web service request and memory usage. DDoS attack detection and protecting will ensure the efficiency of the mobile network resources. This method is necessary for a continuous usage of a wireless network environment for the national security and disaster control.

• 한국사이버테러정보전학회:학술대회논문집
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• 한국사이버테러정보전학회 2004년도 제1회 춘계학술발표대회
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• pp.125-130
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• 2004

인터넷은 본질적으로 신뢰할 수 없는 네트워크들의 집합체이다. 인터넷상에서는 정보의 흐름을 통제하기가 대단히 어렵기 때문에, 산재한 자원을 충분히 활용하면서, 내부의 중요한 자원을 인터넷으로부터 보호해 줄 수 있는 보안문제가 심각하게 대두되고 있다. 최근 발생하는 바이러스 사고와 시스템 불법 침입에 대한 발생률이 과거보다 훨씬 높으며 다양해지고 있다. 이러한 시기에 불법 행동을 막기 위한 침입 차단에 대한 연구가 활발하게 진행 중이며 계속적인 발전을 하고 있다. 본 논문에서는 침입자의 불법 행동에 대한 로그 정보를 XML 포맷 형식에 맞추어 관리자에게 통보하고, 원격으로 제어 할 수 있는 침입 차단 시스템을 개발하여 관리측면에서 발생하는 문제점을 해결하고자 하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제4권4호
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• pp.671-690
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• 2010

The continuous growth of attacks in the Internet causes to generate a number of rules in security devices such as Intrusion Prevention Systems, firewalls, etc. Policy anomalies in security devices create security holes and prevent the system from determining quickly whether allow or deny a packet. Policy anomalies exist among the rules in multiple security devices as well as in a single security device. The solution for policy anomalies requires complex and complicated algorithms. In this paper, we propose a new method to remove policy anomalies in a single security device and avoid policy anomalies among the rules in distributed security devices. The proposed method classifies rules according to traffic direction and checks policy anomalies in each device. It is unnecessary to compare the rules for outgoing traffic with the rules for incoming traffic. Therefore, classifying rules by in-out traffic, the proposed method can reduce the number of rules to be compared up to a half. Instead of detecting policy anomalies in distributed security devices, one adopts the rules from others for avoiding anomaly. After removing policy anomalies in each device, other firewalls can keep the policy consistency without anomalies by adopting the rules of a trusted firewall. In addition, it blocks unnecessary traffic because a source side sends as much traffic as the destination side accepts. Also we explain another policy anomaly which can be found under a connection-oriented communication protocol.

• 한국컴퓨터정보학회논문지
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• 제23권10호
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• pp.65-72
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• 2018

In this paper, we used LSTM as a method to detect abnormal behavior of motors. We fixed the high layout size to 1 and changed the range of the input values and the neural network structure to see what change in power consumption prediction. Now, as the fourth industrial revolution era, smart factories are attracting attention. All the physical actions of smart factories are done using motors. Continuous monitoring of motor malfunctions helps to detect malfunctions and efficient operation. However, it is difficult to acquire the power consumption constantly due to the influence of the noise. We have experimented with a simple experimental environment, a method of predicting similarity to input data by adjusting the range of the input data or by changing the neural network structure.

• 한국수소및신에너지학회논문집
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• 제35권4호
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• pp.428-436
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• 2024

Liquid hydrogen, which operates in cryogenic environments has a density 800 times greater than gaseous hydrogen, making it advantageous for large-scale storage and transportation. However, continuous evaporation due to external heat intrusion and internal heat generation poses challenges. To mitigate heat conduction, various insulation materials are used. In pipe systems, viscous heating effects from turbulence and viscosity, especially in bends, cause heat generation. This study employs computational fluid dynamics (CFD) to analyze the impact of fluid velocity, pressure drop, inner diameter, and curvature radius of pipe bends on viscous heating. Using liquid nitrogen at 77 K as a working fluid, the CFD results showed that increased velocity and pressure drop along with smaller inner diameter and curvature radius enhanced viscous heating, raising fluid temperature.

• 자원환경지질
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• 제4권1호
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• pp.1-9
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• 1971

The "Younger Granites" in Korea were being believed to be late Cretaceous in age and named "Bulkuksa granites" by all previous works until the writer had discovered Jurassic granite in 1963. The present paper is to prove its validity by age dating on these granites which was carried out by Professor Y. Ueda, Tohoku University, Japan. The age of 37 granites samples from various localities ranges from 68 my to 181 my. Of these 10 samples belonged to early Jurassic, 6 samples to mid-Jurassic, 4 samples to late Jurassic, 5 samples to early Cretaceous, and 12 samples to late Cretaceous in age. It is of the writer's opinion that the granites intruded in from early Jurassic to early Cretaceous age belong to Daebo granites and are syntectonic plutons associated with Daebo orogeny, and only those of late Cretaceous age belong to Bulkuksa granites that were associated with Bulkuksa disturbance. Daebo granites are aligned along NE-SW Sinian direction in the middle parts of Korea and crop out in the cores of folded mountains which were formed by Daebo Orogeny, such as Charyong, Noryong, Sobaek, and Dukyu Ranges. On the contrary Bulkuksa granites are restricted in Kyongsang basin and adjacent few localities in distribution and show no alignment. Granites supposedly associated with other disturbances of post-precambrian Have not been found so far in S. Korea. Age dating of granites has revealed that Daebo orogeny might be continuous from Songrim distur bance of late Triassic age. From this viewpoint, it could be assumed that Daedong system of Jurassic age were deposited in separate intermontain basins while Daebo orogeny was active, so that Daedong system in separate localities in Korea could not been correlated in their lithology as well as stratig raphy.

• 동서간호학연구지
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• 제3권1호
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• pp.7-16
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• 1998

This paper reviewed the concept of the energy flow in east and west. The differences in the views of the energy flow between oriental and western thought were compaired according to the ontological point of view. Human body take up energy and material on open system which maintains homeostasis. Human and environment are continuously interacting in a state of co-existence. Human has energy field called "aura" and seven chakra in energy outflow moving came as meridian. Qi is an invisible cosmic energy helping the fundamental human activity and changes. The basic action of Qi is helping the human growth and development, maintain the body temperature and preventing the intrusion of microorganism. In the normal healthy organism, all are maintained in balance and in a continuous circulation of Qi, while illness is the result of the disturbed Qi flow in the aspect of Qi-theory. Although there are differences between oriental and western medicine in approaches to clients, the basic point of view and philosophy have many similarities on fundamental level. An understanding of the basic thought of energy flow and oriental concept of energy flow implies a more comprehensive meaning than the perspective of unitary transformation discussed in modern western thought of energy flow. Now we should avoid narrow view of energy concept and regard energy flow as an integrated concept with Korean culture. Regarding Qi-theory which provides a comprehensive and humanistic and ethical foundation for nursing philisophy through this overview, it is hoped that a contribution will be made to the development of nursing intervention which is suitable to Korean context.

• 대한토목학회논문집
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• 제37권6호
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• pp.981-987
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• 2017

투수성이 큰 화산섬인 제주도에서는 땅속으로 함양된 지하수자원이 가장 중요한 수원이므로 지하수의 적정관리가 매우 중요하다. 특히 가뭄시 지하수의 이용은 염수침투를 유발할 수 있으므로 지하수위 강하에 따른 단계별 제한 조치가 마련되어 있다. 농업용 지하수위에 대한 적정 지하수 이용을 위해서는 보다 장기적인 예측을 통해 사전에 대비하는 것이 필요하다. 이에 본 연구에서는 인공신경망 모형을 이용한 지하수위의 월단위예측기법을 개발하였고, 대표적인 관측공에 대해 적용하였다. 월단위 지하수위를 예측한 결과 학습 및 검증기간 모두 예측 성능이 우수한 것으로 분석되었다. 또한 장기예측을 위해서 입력인자로 월단위 지하수위 예측치를 순차적으로 이용하는 연속지하수위예측 모형을 구축하고 수개월 동안 무강수의 극한조건에 대한 지하수위 저하 양상을 분석하였다.

• 자원환경지질
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• 제27권3호
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• pp.295-311
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• 1994

A comprehensive in-situ tests are performed to define the hydrogeologic and hydrodispersive characteristics such as hydraulic conductivities, longitudinal dispersivity, and average linear velocities as well as conducting flow-net analysis at the study area. The results show that the study area is very heterogeneous so that hydraulic conductivities range from $6.45{\times}10^{-7}$ to $1.15{\times}10^{-5}m/s$ with average linear velocities of 0.34~0.62m/day. Whole groundwater in upper-most aquifer is discharging into the sea with specific discharge rate of $7.2{\times}10^{-3}$ to $1.3{\times}10^{-2}m/day$. The longitudinal dispersivity of the aquifer is estimated about 4.8m through In-situ injection phase test. The area is highly vulnerable to potential contaminant sources due to it's high value of DRASTIC index ranging from 139 to 155 and also under water table condition with very shallow groundwater level. To delineate contaminant plumes of toxic NaOH and carcinogenic benzene when these substances are assumed to be leaked through existing TSDF at the study area by unexpected accidents or spill, Aquifer Simulation Model (ASM) including Flow and Transport Model is used. Te simulated results reveal that the size of NaOH plume after 5 years continuous leak is about $250{\times}100m$ and benzene after 10 years, $490{\times}100m$. When the groundwater is abstracted about 50 days, which is maximum continuously sustained no-precipitation period during 30 years, with pumping rate of $100m^3/day$, THWELL program shows that the groundwater is adversly affected by sea water intrusion.

• 방사성폐기물학회지
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• 제6권4호
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• pp.329-346
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• 2008

중저준위 방사성폐기물의 영구처분을 위하여 건설되는 월성원자력환경관리센터의 1단계 폐쇄후 안전성평가에 대하여 기술하였다. 처분시설의 건설운영허가를 위하여 작성된 안전성평가에 대하여 평가개요, 처분시설의 폐쇄개념, 처분부지에 대한 지하수 유동특성을 이용하여 평가를 위한 시나리오의 개발과정과 도출된 평가대상 시나리오에 대한 개념을 기술하였다. 폐쇄후 안전성평가 모델링을 위한 평가도구, 입력인자와 개별 시나리오에 대한 핵종누출 모델링, 기체발생 및 기체이동 모델링, 인간침입 모델링과 생태계 모델링에 대하여 기술하였다. 처분시설의 폐쇄후 안전성 평가시나리오에 대하여 국내 규제치를 만족하는 것으로 평가되었으며 향후 처분시설 안전성에 대한 불확실성 저감과 신뢰성 증진을 위한 노력을 지속적으로 수행할 예정이다.