• 한국컴퓨터정보학회논문지
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• 제14권4호
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• pp.69-76
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• 2009

인터넷을 구성하는 IP 기반의 네트워크 구성은 다양한 회사의 라우터와 스위치 장비들로 구성되어 있다. 다양한 장비의 구성은 웜, 바이러스, DDoS 등과 같은 유해트래픽을 필터링하기 위하여 각 회사마다 서로 다른 형태의 문자 명령어 기반인 CLI가 주로 사용되고 있어 관리 및 제어의 복잡성이 높다. 이의 대안으로 IETF에서는 XML 기반으로 구성관리 표준을 NETCONF 작업 그룹에서 제정하고 있지만, NETCONF의 명령어 처리 단계에서 처리되는 명령어 몇 가지만 표준으로 정의되어 있고, 유해트래픽을 차단하기 위한 XML 명령어는 각 회사 장비마다 서로 다르게 되어 있으므로 이 기종 장치간의 일관된 제어 명령어 처리가 어렵다. 본 논문에서는 이 기종 장치의 일관된 제어 명령어를 통하여 네트워크로 유입되는 유해트래픽을 싱크홀 라우터로 우회시키고, 유입된 트래픽을 대상으로 유해성 여부를 판단하여 다양한 공격을 효과적으로 차단할 수 있는 제어시스템을 설계하여, 유해트래픽으로 부터 보호되고, 보다 안정된 네트워크 효율을 높일 수 있는 방법을 제안하였다.

• ETRI Journal
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• 제43권4호
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• pp.674-683
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• 2021

A trust-aware secure routing protocol (TSRP) for wireless sensor networks is proposed in this paper to defend against varieties of attacks. First, each node calculates the comprehensive trust values of its neighbors based on direct trust value, indirect trust value, volatilization factor, and residual energy to defend against black hole, selective forwarding, wormhole, hello flood, and sinkhole attacks. Second, any source node that needs to send data forwards a routing request packet to its neighbors in multi-path mode, and this continues until the sink at the end is reached. Finally, the sink finds the optimal path based on the path's comprehensive trust values, transmission distance, and hop count by analyzing the received packets. Simulation results show that TSRP has lower network latency, smaller packet loss rate, and lower average network energy consumption than ad hoc on-demand distance vector routing and trust based secure routing protocol.

• 한국자기학회지
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• 제19권2호
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• pp.67-73
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• 2009

지하에 존재하는 빈 공간이 지상에서의 자속밀도 변화에 미치는 영향을 땅의 밀도와 측정높이에 따른 변화의 차이로 분석하였다. 밀도가 다른 지표면과 함몰지 및 지하터널이 있는 지표면에 대한 지자기의 자속밀도 분포를 플럭스게이트형 마그네토미터를 사용하여 조사하였다. 지하의 밀도가 감소하거나 빈 공간이 존재하면 지상에서의 자속밀도가 감소하는데, 경계에서부터 서서히 감소하여 중심부에서 가장 낮은 자속밀도를 나타낸다. 빈 공간에 의한 자속밀도의 감소는 지하 80m에 위치한 터널에 의해서도 관찰된다. 이러한 자속밀도 감소현상을 이용하면 지하의 천부에 존재하는 빈 공간, 저밀도 지역, 파쇄대 및 함몰지를 탐사할 수 있을 것으로 보인다.

• 한국농공학회논문집
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• 제46권2호
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• pp.3-14
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• 2004

This study was conducted to assess the possibility of the field application of the iceharbor-type precast fishway. When overflow depth of weir is 4.0 cm in model fishway, upper part velocities appear appropriate for upstream migration of fish and the lowest overflow wall (right line) in lower part has shown velocity distribution more or less inadequate for upstream migration. Except that right line, left and middle line revealed that velocities are appropriate for upstream migration of fish. Therefore, we concluded that this fishway owing to be not broad growth width of overflow velocities according to increasing discharges can correspond to variation of water level. Also We consider that various velocities in fishway were effective, because slow velocity line can guide flow for upstream migration. For low flow, the arrangement of different crest level or each overflow part (higher left, middle and lower right, or lower left, middle and higher right) was more effactive than unform crert level. Hole plays an important role as migration pass during drought and flood flow. Therefore, We concluded that this fishway can cope with water depth variation by various overflow wall height change and raise the field applicability with better performance hydraulically and structurally.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권12호
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• pp.5442-5463
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• 2016

Designing efficient routing protocols for a wireless sensor network with mobile sinks (mWSN) is a challenging task since the network topology and data paths change frequently as sink nodes move. In this paper, we design a novel lightweight reactive ring based routing protocol called R3, which removes the need of proactively maintaining data paths to mobile sinks as they move in the network. To achieve high packet delivery ratio and low transmission cost, R3 combines ring based forwarding and trail based forwarding together. To support efficient ring based forwarding, we build a ring based structure for a network in a way such that each node in the network can easily obtain its ring ID and virtual angle information. For this purpose, we artificially create a virtual hole in the central area of the network and accordingly find a shortest cycled path enclosing the hole, which serves as base ring and is used for generating the remaining ring based structure. We accordingly present the detailed design description for R3, which only requires each node to keep very limited routing information. We derive the communication overhead by ring based forwarding. Extensive simulation results show that R3 can achieve high routing performance as compared with existing work.

• Nuclear Engineering and Technology
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• 제56권3호
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• pp.1052-1065
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• 2024

Advanced Pressurized Water Reactors (APWRs) and Boiling Water Reactors (BWRs) employ a suppression pool as a heat sink to prevent containment overpressure. Steam can be discharged into the pool through multi-hole spargers or blowdown pipes in both normal and accident conditions. Direct Contact Condensation (DCC) creates sources of momentum and heat. The competition between these two sources determines the development of thermal stratification or mixing of the pool. Thermal stratification is of safety concern as it reduces the cooling capability compared to a completely mixed pool condition. In this work we develop a scaling approach to prediction of the thermal stratification in a water pool induced by steam injection through spargers. Experimental data obtained from large-scale pool tests conducted in the PPOOLEX and PANDA facilities, as well as simulation results obtained using validated codes are used to develop the scaling. Two injection orientations, namely radial injection through multi-hole Sparger Head (SH) and vertical injection through Load Reduction Ring (LRR), are considered. We show that the erosion rate of the cold layer can be estimated using the Richardson number. In this work, scaling laws are proposed to estimate both the (i) transient erosion velocity and (ii) the stable position of the thermocline. These scaling laws are then implemented into a 1D model to simulate the thermal behavior of the pool during steam injection through the sparger.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 봄 학술발표회 논문집
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• pp.991-996
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• 2002

In this study, there are kind of property experiments like fluidity, compressive strength, bleeding measurement, concrete sink for CFT use high fluidity concrete. The property difference between before transmit and after transmit concrete in the mock up test with ready mixed concrete equipment is examined. The variable factors in mock up are diaphragm existence and nonexistence, diaphragm placing hole sizes. To investigate the concrete property under diaphragm, concrete packing ability tests is peformed. High fluidity and strength concrete which satisfied with mix criteria could apply to building construction field. It it is quality managed with use of packing ability analysis.

• 터널과지하공간
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• 제27권6호
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• pp.393-405
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• 2017

광해발생에 대한 국민적 관심이 높아짐에 따라 한국광해관리공단에서는 광해방지 기본계획에 따른 광해 방지사업을 수행 중에 있다. 본 사례보고에서는 3단계 광해방지 기본계획의 지반침하 방지사업의 원활한 수행에 있어 참고자료로 활용할 수 있도록 광산지역에서 발생하는 지반침하를 방지하기 위한 지반침하방지사업 추진절차를 설명하고 설계 및 시공사례와 연구사례를 소개하였다.

• 한국건축시공학회지
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• 제2권1호
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• pp.163-169
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• 2002

In this study, there are kind of property experiments like fluidity, compressive strength, bleeding measurement, concrete sink for CFT use high fluidity concrete. The property difference between before transmit and after transmit concrete in the mock up test with ready mixed concrete equipment is examined. The variable factors in mock up are diaphragm existence and nonexistence, diaphragm placing hole sizes. To investing the concrete Property under diaphragm, concrete packing ability, hydration heat, core specimen strength tests are performed.

• 대한안전경영과학회지
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• 제19권2호
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• pp.15-29
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• 2017

In changes of social environment, change of the use of land due to the change of residence type, industry and urban structure is an influential factor to safety vulnerable social group. From PTSD from disaster experience point of view, experience of disaster, damage from disaster, witness of disaster make people experience anxiety and confusion, increase the anxiety toward disaster and lead to difficulty in daily lives. As for the result of analyzing anxiety factors regarding disaster damage potential composed of 20 items of safety manager, damage potential of sink hole which recently rapidly increased was the highest, and followed by anxiety from safety damage potential of family, anxiety from phone call damage. Likewise, if the anxiety toward disaster damage potential is digitized, it contributes to setting safety management planning for disaster prevention as it visualizes the risk.