• Journal of the Korea Convergence Society
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• v.9 no.9
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• pp.61-67
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• 2018

Emulab software was developed by the team of University of Utah and it has been replicated at dozens of other sites in the world. Although KREONET Emulab, which established by the Korea Institute of Science and Technology Information, has only a modest number of compute nodes it has been provided an ideal playground to conduct various research for network protocols, cyber security and convergence research. A testbed is a critical enabler of experimental research and researchers only carry out the experiments that are supported by the testbed. This paper outlines the Utah Emulab's status and use types among the last 10 years of operation results and compares them with the ones with the KREONET Emulab. In addition, Testbed-as-a-Service(TaaS) is discussed to upgrade the testbed for the convergence research community services.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.10
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• pp.1117-1130
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• 1992

In this study, we propose a protocol for the communication between process groups required during message transfers. This is accomplished by an efficient process management of distributed systems connected by computer networks. For a single process group, a multicast protocol was proposed, which can control message flows while maintaining the order of messages sent or delivered. Through use of membership-related services, a member composing a process group may leave and join the current a membership anytime during execution. Moreover, message delivery can be delayed by using a logical vector time stamp. The functionality of the message delivery includes a virtual synchronization in response to a change in membership.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.599-599
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• 2015

최근 지구온난화로 인한 기후변화로 자연재해의 형태는 점차 대형화, 다양화 되고 있는 추세이다. 이와 같이 기후변화에 의한 강도 높은 국지성 집중호우의 영향으로 막대한 인명 및 재산 피해를 주고 있으며, 이를 최소화하기 위한 대안을 마련하기 위해서는 정확한 홍수량 산정과 홍수방지 시설물들이 필요하다. 본 연구에서는 탐진강 하구부의 홍수방어계획 수립을 위해 가상의 분수로 설치 유무에 따른 수리특성을 비교 분석하고자 HEC-RAS모형과 RMA-2모형을 적용하여 모델링을 수행하였다. 먼저 1차원 수리모형인 HEC-RAS모형을 이용하여 탐진강 본류의 홍수위 저하 효과를 검토한 결과 현 상태와 비교했을 때 분수로 설치 시 홍수위가 최대 0.35m저하 되는 것으로 분석되었다. 2차원 수리모형인 RMA-2모형을 적용하기 위해 유한요소망을 구축하고 탐진강 본류 및 분수로의 흐름특성을 분석하였다. 그 결과 분수로 분류 후 탐진강 본류의 유속 및 수위가 저하되는 것으로 나타났으며, 분수로의 유속은 대체적으로 3.0m/s이하로 분석되었다. 분수로 설치 시 탐진강 본류의 홍수량이 일부 감소하나 유사이송능력도 함께 감소하여, 탐진강 하구부 하상퇴적이 예상됨으로 향후 추가적인 연구를 통해 합리적인 홍수방어계획을 제시할 예정이다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.2
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• pp.457-469
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• 2018

This study aimed to investigate the fundamental reasons for the presence of multi-homed host and the risks associated with such risky system. Furthermore, multi-homed host detection methods that have been researched and developed so far were compared and analyzed to determine areas for improvement. Based on the results, we propose the model of an improved automatic detection system and we implemented it. The experimental environment was configured to simulate the actual network configuration and endpoints of an organization employing network segmentation. And the functionality and performance of the detection system were finally measured while generating multi-homed hosts by category, after the developed detection system had been installed in the experiment environment. We confirmed that the system work correctly without false-positive, false-negative in the scope of this study. To the best of our knowledge, the presented detection system is the first academic work targeting multi-homed host under agent-based.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.6
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• pp.379-386
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• 2014

Recently, middleboxes play a key role in many network settings such as firewalls, VPN gateways, proxies, intrusion detection and prevention systems, and WAN optimizers. However, achieving the performance and security benefits that middleboxes offer is highly complex, and therefore it is essential to manage middleboxes efficiently and dynamically. In this respect, Software-Defined Networking (SDN) offers a promising solution for middlebox policy enforcement by using logically centralized management, decoupling the data and control planes, and providing the ability to programmatically configure forwarding rules. Also, cloud computing and distributed Network Function Virtualization (NFV) can enable to manage middleboxes more easily. We introduce SDN-based middlebox management framework in integrated wired and wireless networks and discuss the further issues.

• Smart Media Journal
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• v.8 no.2
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• pp.29-38
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• 2019

With the advancement of information and communication technology, tactical networks are continuously being converted to All-IP future tactical networks that integrate all application services based on Internet protocol. Futuristic tactical mesh network is built with tactical WAN (wide area network) nodes that are inter-connected by a mesh structure. In order to guarantee QoS (quality of service) of application services, tactical service mesh (TSM) is suggested as an intermediate layer between infrastructure and application layers for futuristic tactical mesh network. The tactical service mesh requires dynamic QoS monitoring and control for intelligent QoS coordination. However, legacy networking nodes used for existing tactical networks are difficult to support these functionality due to inflexible monitoring support. In order to resolve such matter, we propose a tactical mesh WAN node as a hardware/software co-designed networking node in this paper. The tactical mesh WAN node is conceptually designed to have multi-access networking interfaces and virtualized networking switches by leveraging the DANOS whitebox server/switch. In addition, we explain how to apply eBPF-based traffic monitoring to the tactical mesh WAN node and verify the traffic monitoring feasibility for supporting QoS coordination of tactical-mesh traffic.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.1068-1072
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• 2005

조석이란, 해면의 완만한 주기적 승강을 말하며, 보통 그 승강은 1일 약 2회이나, 곳에 따라서는 1일 1회의 곳도 있다. 조석에 있어서는 이 밖에 수일의 주기를 갖는 약간 불규칙한 승강, 반년, 또는 1년을 주기로 하는 다소 규칙적인 승강까지 포함하여 취급한다. 그러나, 각 항만마다 갖는 특정적인 주기인 수분내지 수십분의 주기의 승강은 조석으로 취급하지 않는다. 조석은 해양의 제현상 중에서 예측가능성이 가장 큰 현장으로 이는 조석이 천체의 운행과 연관되기 때문이다. 조석이란 지구로부터 일정한 거리에서 각 고유의 속도를 가지는 적도상을 운행하는 무수의 가상천체에 기인하는 규칙적인 개개의 조석을 합성한 것이며 이 개개의 조석을 분조(Constituent)라 한다. 여기에서 사용되는 신경망 모형은 입력과 출력으로 구성되는 블랙박스 모형으로서 하나의 시스템을 병렬적으로 비선형적으로 구축할 수 있다는 장점 때문에 과거 하천유역의 강우-유출과정에서의 경우 유출현상을 해석하고 유출과정을 모형화 하기 위해 사용하였다. 본 연구에서는 기존의 조위 예측방법인 조화분석법이 아닌 인공신경망을 이용하여 조위예측을 실시하였다. 학습이라는 최적화 과정을 통해 구조와 기능이 복잡한 자연현상을 그대로 받아들여 축적시킴으로써 이를 지식으로 현상에 대한 재현능력이 뛰어나고, 또한 신경회로망의 연상기억능력에 적용하여 수학적으로 표현이 불가능한 불확실한 조위곡선에 적용하기에 유리한 장점을 가지고 있다. 본 연구의 목적은 과거 조위이론을 통해 이루었던 조위예측을 우리가 알기 쉬운 여러 기후인자(해면기압, 풍향, 풍속, 음력 등)에 따른 조위곡선을 예측하기 위해 신경망 모형을 이용하여 여수지역의 조위에 적용하여 비교 분석하고자 한다. May가 제안한 공식을 더 확장하여 적용할 수 있는 실험 공식으로 개선하였으며 다양한 조건에 대한 실험을 수행하여 보다 정밀한 공식으로 개선할 수 있었다.$10,924m^3/s$ 및 $10,075m^3/s$로서 실험 I의 $2,757m^3/s$에 비해 통수능이 많이 개선되었음을 알 수 있다.함을 알 수 있다. 상수관로 설계 기준에서는 관로내 수압을 $1.5\~4.0kg/cm^2$으로 나타내고 있는데 $6kg/cm^2$보다 과수압을 나타내는 경우가 $100\%$로 밸브를 개방하였을 때보다 $60\%,\;80\%$ 개방하였을 때가 더 빈번히 발생하고 있으므로 대상지역의 밸브 개폐는 $100\%$ 개방하는 것이 선계기준에 적합한 것으로 나타났다. 밸브 개폐에 따른 수압 변화를 모의한 결과 밸브 개폐도를 적절히 유지하여 필요수량의 확보 및 누수방지대책에 활용할 수 있을 것으로 판단된다.8R(mm)(r^2=0.84)$로 지수적으로 증가하는 경향을 나타내었다. 유거수량은 토성별로 양토를 1.0으로 기준할 때 사양토가 0.86으로 가장 작았고, 식양토 1.09, 식토 1.15로 평가되어 침투수에 비해 토성별 차이가 크게 나타났다. 이는 토성이 세립질일 수록 유거수의 저항이 작기 때문으로 생각된다. 경사에 따라서는 경사도가 증가할수록 증가하였으며 $10\% 경사일 때를 기준으로 $Ro(mm)=Ro_{10}{\times}0.797{\times}e^{-0.021s(\%)}$로 나타났다.천성 승모판 폐쇄 부전등을 초래하는 심각한 선

• The Transactions of the Korea Information Processing Society
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• v.4 no.11
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• pp.2832-2839
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• 1997

In this paper, a testing architecture and procedure that an idle ATM virtual channel can be utilized for TCP channel is proposed. Four kinds or methodologies for protocol conformance testing have been standardized in ISO. Remote testing method used popularly have some disadvantages that developer must operate system manually in case of System Under Test (SUT) active testing and we cannot control and observe Implementation Under Test (IUT) often. It is proper to adopt distribute testing method than remote test in order to maximize test coverage and optimize fault coverage for conformance testing in ATM systems, and it is required that TCP channel is prepared for distribute testing method. The proposed architecture can adopt distributed testing method without extra physical channel for testing control. Also we can maximize the test coverage and implement the automation of testing without intervention of operator sustaining normal operation of ATM equipment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.5
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• pp.863-869
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• 2008

In this paper, a system with sensor network security mechanism which can be applied to home network structure is designed and it is implemented on a virtual network of a home network middleware. The basic structure of home networking middleware supports one-to-one (unicast) or broadcast communication mode between the lookup server and service nodes on the network. Confidentiality and authentication are key security factors of the one-to-one communication and user authentication is crucial for broadcasting mode. One of the sensor network's security techniques SPINS consists of SNEP and ${\mu}TESLA$. The SNEP ensures confidentiality and authentication, and ${\mu}TESLA$ provides broadcast authentication. We propose a SPIN based home network middleware and it is implemented by using the CBC-MAC for MAC generation, the counter mode (CTR) for message freshness, the pseudo random function (PRF) and RC5 as encryption algorithm. The implementation result shows that an attacker cannot decrypt the message though he gets the secure key because of CTR mode. In addition, we confirmed that a received message of the server is authenticated using MAC.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.5
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• pp.673-681
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• 2011

Among the network information services combined with a number of security technologies and required security policies, Infrastructure as a Service, a hardware plat-form service of Cloud Computing, has been provided since 2011. It is more or less similar to the existing central concentration method services, in terms of the specifications and technical aspects for given hardware category, but it is entirely different from them in that it overcomes the spatial limitations of specific network and targets the public network. Information security technology has also been prospering so that it could ensure the stability of offered hardware plat-forms. As currently supported hardware, Internet Data Center has been provided by virtualizing the previously offered servers and discs (backup discs), but the hardware plat-forms offered are somewhat limited. Meanwhile, the areas of security fields for offered services are confined to the center or include the TCP/IP-based SSL (Secure Sockets Layer) for the public network connected with clients, which shows that microscopic access security policies have been used. Therefore, this study was aimed to provide a realistic security mechanism for realizing defense policy, by expanding service areas into security devices and suggesting Diskless and Stateless security policy based high-speed synchronous network infrastructure.