• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.635-637
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• 2016

센서 네트워크에서 각 센서 노드의 에너지 소모를 최소화하여 에너지 소모를 줄임으로써 망의 지속시간을 늘이는 것이 중요하다. 기존의 MAC(Medium Access Control) 프로토콜은 채널 폴링 기법을 이용하여 효율적인 에너지 관리에 대한 해결책을 제시 하였으나, 그러한 방식에 따른 각 노드의 Duty Cycle이 길어짐으로써 발생하는 에너지 소모에 대한 해결책은 제시하지 못하였다. 본 논문에서는 기존의 채널 폴링과 함께 스케쥴링 알고리즘을 적용하여 Duty Cycle의 주기를 줄임으로써 에너지 소모를 줄인다. 특히 이 방식을 이용하여 멀티홉과 과다한 트래픽에 대한 성능의 평가를 위해 실험을 통해 제안하는 프로토콜의 우수한 성능을 보인다.

• Journal of the Korea Computer Industry Society
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• v.5 no.3
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• pp.393-404
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• 2004

Recently, public home have used a more than two computer connected with network, and several home appliances using independently with internet or network are developing to be related closely with the network. Therefore, the home utilized for a simple terminal of the global network in the past is being expanded to another part of the sub network. For a variety of connecting home-area protocols with the existing existing network, we require a new Residential Gateway(RG) that does not only make the home-area network operating in the sub network but also connects to the external network. In this paper, RG has intrinsic limits against flexible service due to IP address assignment and hardware capacity. In order to solve this problem in the RG, we propose a Management Server(MS). The MS that offers the integrated managements and control services for a variety of devices connected the RG in the home-area. It can not only solve the dynamic IP address assigning problem but also assigns private IP addresses to the home network devices through the Network Address Translation(NAT). It also provides somewhat useful functions for the home network and the RG for other additional services. <중략> The MS is using a SNMP protocol for managing the RG in the domain, a polling method of the MS and the RG compose a sequence polling method, a polling method using a multi-process and a multi-thread. In this paper, we introduce a problem with polling method separately, show a polling method between the MS and the RG using a multi-thread.

• Journal of Korea Multimedia Society
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• v.19 no.10
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• pp.1808-1815
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• 2016

TPSN(Timing-sync Protocol for Sensor Networks), the representative of time synchronization protocol, has been already developed to provide time synchronization among nodes in wireless sensor networks. Even though the TPSN's method has been referenced by so many other time synchronization schemes for resource-constrained networks like wireless sensor networks or low power personal area networks, it has some inefficiency in terms of power consumption and network-wide synchronization time (or called convergence time). The main reason is that each node in TPSN needs waiting delay to solve the collision problem due to simultaneous transmission among competing nodes, which causes more power consumption and longer network convergence time for a network-wide synchronization. In this paper an improved scheme is proposed by changing message exchange method among nodes. The proposed scheme not only shortens network-wide synchronization time, but also reduce collision traffic which lead to needless power consumption. The proposed scheme's performance has been evaluated and compared with an original scheme by simulation. The results are shown to be better than the original algorithm used in TPSN.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2000.11a
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• pp.413-418
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• 2000

For Pneumatic system control, we need a data transmission system with high speed and high realibility for information interchange between main computer and solenoid valves and I/O devices. This paper presents a set of design techniques for a data communication system that is mainly used for pneumatic system control. For this purpose, we first designed hardware modules for an interface between central control module and local node that handles the operation of solenoid valves. In addition we developed a communication protocol for construction of RS-485 based multidrop network, and this protocol is basically designed with a kind of polling technique. Finally we evaluated performance of the developed system. The field test results show that, even under high noise environment, the data transmission of 375Kbps rate is possible up to 1,000m without using repeater. In addition, the system developed in this research is proved to be used easily for extension of a communication network because of its module structure.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.2
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• pp.455-463
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• 1999

This study is on the development of an engine monitoring system which can be applied not only for mid-size vessels but also small vessels less than 20 gross tonnage. Monitoring system consists of a set LMU(Local Monitoring Unit) that collect data from local machinery, a host computer that controls LMU and a stable communication system which adopts CSMA/CD protocol. The LMU is composed of 80C196KC microprocessor, which consists of CPU, digital input/output, analog input/output and communication module. Communication system between the host computer(compatible IBM PC) and LMUs is the multidrop configuration using RS-485 method and confirmed high performance communication by the aid of polling method as well as carrier sense multiple access with collision detection(CSMA/CD) protocol.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.150.2-150
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• 2001

For pneumatic system control, we need a data transmission system with high speed and reliability for information interchange between main computer and I/O devices. This paper presents a set of design techniques for a data communication system that is mainly used for pneumatic system control. For this purpose, we first designed hardware modules for an interface between central control module and local node that handles the operation of solenoid valves. In addition, we developed a communication protocol for construction of RS-485 based multi-drop network, and this protocol is basically designed with a kind of polling technique. Finally we evaluated performance of the developed system. The field test results show that, even under high noise environment, the data transmission of 375Kbps rate is ...

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1152-1156
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• 2003

For pneumatic valve system control, we need a serial data transmission system with high speed and reliability for information interchange between main computer and I/O devices. This paper presents a set of design techniques for a data communication system that is mainly used for pneumatic valve system control. For this purpose, we first designed hardware modules for an interface between central control module and local node that handles the operation of solenoid control valves. in addition, we developed a communication protocol for construction of rs-485 based multi-drop network and this protocol is basically designed with a kind of polling technique. Finally we evaluated performance of the developed system. the field test results show that, even under high noise environment, the data transmission of 375kbps rate is possible up to 1,500meter without using repeater. In addition, the system developed in this research is easily to be extended for a communication network because of its modular structure.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.865-870
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• 2001

For pneumatic system control, we need a data transmission system with high speed and high reliability or information interchange between main computer and solenoid valves and I/O devices. This paper presents a set of design techniques for a data communication system that is mainly used for pneumatic system control. For this purpose, we first designed hardware modules for an interface between central control module and local node that handles the operation of solenoid valves. In addition we developed a communication protocol for construction of RS-485 based multidrop network, and this protocol is basically designed with a kind of polling technique. Finally we evaluated performance of the developed system. The field test results show that, even under high noise environment, the data transmission of 375Kbps rate is possible up to 1,000m without using repeater. In addition, the system developed in this research is proved to be used easily for extension of a communication network because of its module structure.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.6B
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• pp.531-537
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• 2004

EPON which is the economical technology of FTTH is being actively researched as one of next generation of subscriber configurations. EPON based on Ethernet should provide subscriber with dynamic bandwidth allocation so as to support QoS. Allocation per service in grade should be satisfied resulting from the increment of the latest multimedia application arid consumption. In this paper, New Algorithm is proposed to serve differential service on MAC protocol. The delay characteristic of packet and stability are analyzed that is shown the QoS of EPON network.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.7
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• pp.31-40
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• 2004

In this paper, we analyze mathematically the performance of the gated service scheduling in the Interleaved Polling with Adaptive Cycle Time(IPACT) was proposed to control upstream traffic for Gigabit Ethernet-PONs. In the analysis, we model EPON MAC protocol as a polling system and use mean value analysis. We divide arrival rate λ into three regions and analyze each region accordingly In the first region in which λ value is very small, there are very few ONUs' data to be transmitted. In the second region in which λ has reasonably large value, ONUs have enough data for continuous transmission. In the third region, ONUs' buffers are always saturated with data since λ value is very large. We obtain average packet delay, average Queue size, average cycle time of the gated service. We compare analysis results with simulation to verify the accuracy of the mathematical analysis. Simulation requires much time and effort to evaluate the performance of EPONs. On the other hand, mathematical analysis can be widely used in the design of EPON systems because system designers can obtain various performance results rapidly. We can design appropriate EPON systems for varioustraffic property by adjusting control parameters.