• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.370-372
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• 2005

최근 초고속 인터넷의 확산과 IT기반의 가전기기들이 등장하면서 흠 네트워크에 대한 관심이 집중되어 지고 있다. 이러한 배경은 사람들에게 좀 더 안전하고 편리한 주거 환경을 제공한다. 하지만 기존의 제어 방식은 홈 서버 내의 디지털 기기만을 제어 한다. 이러한 단독 제어는 외부 환경으로부터의 영향에 대한 예방을 할 수 없다는 문제점이 있다. 본 논문에서는 이러한 문제점을 해결하기 위한 방법으로 홈 네트워크 그룹에 홈 서버들을 관리하는 관리 그룹 서버를 두고 홈 서버들의 정보를 이용하여 방재, 방범등에 대한 문제 예방을 가능하게 하였다. 또한 온톨로지를 사용하여 상황을 인지하고 추론하며 추론 결과는 각 홈 서버에게 전송되어 디지털 기기들을 제어하게 된다. 이로 인하여 주거 환경의 신뢰성 있는 안전과 편리함을 확보할 수 있다.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.12
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• pp.1229-1233
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• 2010

In event-driven wireless sensor networks, network congestion occurs when event data, which have higher transmission rates than periodic sensing data, arc forwarded to bottleneck links. As the congestion continues, congestion collapse is triggered, so most of packets from source nodes are failed to transmit to a sink node. Rate control schemes can be a solution for preventing the congestion collapse problem. In this paper, a rate control scheme that each node controls child node's data rate based on congestion patterns is proposed. Experiments show that the proposed scheme effectively controls network congestion and successfully transmits more event data packets to a sink node than existing rate control schemes.

• Annual Conference of KIPS
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• 2003.11b
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• pp.705-708
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• 2003

본 논문에서는 무선 센서 네트워크의 특성을 고려한 미디어제어 프로토콜의 설계에 있어서의 고려사항 및 설계기법에 대해서 제안하고 있다. 무선 센서 네트워크는 제한된 에너지를 가지는 배터리를 에너지원으로 사용하는 센싱 디바이스들로 구성되어 있으며, 이러한 디바이스들로 구성된 네트워크는 하나 혹은 그 이상의 공통의 작업을 수행하는데 그 목적이 있다. 일반적으로 무선 센서네트워크는 ad hoc 헝태의 구조를 가지며, 각각의 노드들은 장시간동안 비활성화 상태에 머무르게 되며, 센싱을 하기 위한 특정 이벤트가 발생하였을 때만 활성 상태로 전이하게 된다. 이와 같은 센서 네트워크의 특성은 IEEE802.11 과 같은 기존의 무선 미디어 제어 프로토콜과는 차별성을 띄게 된다. 센서 네트워크는 노드별 미디어 접근 공정성이나 시간지연보다는 에너지절약과 위상자동설정에 더 중점을 두고 있기 때문에 이에 적합한 미디어 제어 기술이 필요한 것이다. 본 고에서는 에너지 소모를 최소화하고 위상 자동 설정을 지원하기 위한 3 가지의 기법들에 대해서 제안하고자 한다. 첫째로 이벤트 발생 여부에 따른 노드의 신호감지 및 Sleep 상태 전이 및 이웃 노드들과의 가상동기화기법을 이용한 에너지 절약 기법에 대해서 제안하고, 충돌회피 기법에 대해서 살펴보도록 하겠다.

• Journal of the Korean Society of Safety
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• v.17 no.4
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• pp.196-201
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• 2002

Web-based predictive maintenance (PM) utilizes Virtual Device Network (VDN). VDN inevitably the implementation of Distributed Monitoring and Control Networks (DMCN). In general, one needs to integrate fieldbus protocol and TCP/IP to realize DMCN over IP network or internet, which can be viewed as Virtual Device Network (VDN). Interoperability between devices and equipments is essential to enhance the quality and the performance of predictive maintenance (PM). This paper investigates the transmission characteristics of VDN and suggests a basic framework for web-based PM using DMCN over IP network.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.839-842
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• 2005

As various mobile technologies, sensor technologies, and remote control technologies are growing and quality of life is enhanced, researches and developments on home network are actively on going. Currently, some network service providers and construction corporations are going to provide home network service, but neither secure nor efficient, So, in this paper, we propose a security framework for providing various secure user authentication mechanisms and efficiently controlling services in home network. Namely, we are going to provide active home network security services with home gateway-based security policy, which locates on the gateway of each home.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.10
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• pp.2457-2464
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• 2015

Distributed Networked Control Systems (NCSs) through wireless networks have a tremendous potential to improve the efficiency of various control systems. In this paper, we define the State Update Interval (SUI) as the elapsed time between successful state vector reports derived from the NCSs. A simple expression of the SUI is derived to characterize the key interactions between the control and communication layers. This performance measure is used to formulate a novel optimization problem where the objective function is the probability to meet the SUI constraint and the decision parameter is the channel access probability. We prove the existence and uniqueness of the optimal channel access probability of the optimization problem. Furthermore, the optimal channel access probability for NCSs is lower than the channel access probability to maximize the throughput. Numerical results indicate that the improvement of the success probability to meet the SUI constraint using the optimal channel access probability increases as the number of nodes increases with respect to that using the channel access probability to maximize the throughput.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.4
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• pp.266-278
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• 2013

In this paper, to manage the efficient control of IP packet flows crossing multi-provider networks such as Internet, we propose a SDN(Software Defined Networking)-based policy controller. The proposed policy controller leverages the visibility of underlying network and manages both virtual links and ports to inter-connect networking elements. The controller is capable of quickly composing multiple on-demand virtual networks and dynamically managing the composed networks, thus it can provide more flexible and optimized overlay networking environment to end-user applications. More specifically, we first look into the proposed structure and features of policy controller. With two kinds of service applications, we then verify the applicability of the proposed controller by evaluating its service composition time.

• Communications of the Korean Institute of Information Scientists and Engineers
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• v.19 no.4
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• pp.16-25
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• 2001

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.823-826
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• 2008

This paper will show how to design home network management system in the wired/wireless environment using graphical language LabVIEW, J2ME and to apply the design to monitoring and remote controling for the information devices at home. This paper also provides with efficiency of device control and current status check according to the circumstances of administrators by constructing the wire/wirelessly integrated administration system. It means the administrators can access to central administration server and acquire the control right through web being able to operate the system with flexibility and can access to the server without computer whenever, wherever they need to control and administrate it through this wired/wireless unit easily.

• Journal of Korea Multimedia Society
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• v.11 no.10
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• pp.1366-1375
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• 2008

To verify correct operation of measuring instruments, we request the verification of measuring instrument to the agency that holds inspection devices. This works requires time and cost to the company. For this reason. We proposed "Smart Network Interface Card Model" for remote control of measuring instruments. Our model based on Web adapter, can add, delete and change the program to an existing web adapter from remote system. Furthermore, more than one program can be loaded, and can be updated from the remote system of internet. And also we can change the verification requirement of measuring instrument, hence it makes more good quality and competitive power of instruments.