• Proceedings of the Korean Information Science Society Conference
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• 2003.10c
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• pp.475-477
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• 2003

본 논문에서는 IEEE 802.11 을 기반으로 하는 무선 Ad Hoc 망에서 데이터의 송신자 노드와 목적지 노드의 중간 노드들의 전송을 방해하고 채널을 경쟁하는 경쟁노드들이 Shortest­path 라우팅 경로 설정에 미치는 영향을 분석한다. 데이터를 전송하는 중간 노드들이 다수의 경쟁노드를 가지고 있을 경우 MAC delay 가 큰 변수로 작용하며 multi­hop 환경이기 때문에 hidden terminal 문제가 발생한다. 또한 AODV 와 같은 on­demand 라우팅 알고리즘은 경로를 찾기 위해서 Route Request 패킷을 브로드캐스트 하는데 이때 브로드캐스트 패킷의 성공적인 전송이 보장되지 않기 때문에 경쟁노드의 방해가 심한 경우 경로를 찾는데 실패할 가능성이 높아진다. 본 논문에서는 이러한 특성들을 근거로 경쟁노드의 수와 분포가 라우팅 경로 선택에 영향을 미친다는 것을 지적한다.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10e
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• pp.124-126
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• 2002

Voice over Internet Protocol(VoIP) is expected to be a major application on the Internet in the future This paper propose an approach to VoIP that uses Differentiated Service and Multi-protocol Label Switching(MPLS) to provide quantitative QoS guarantees over an IP network. An algorithm that determines QoS-constrained routes is proposed and a framework that uses such an algorithm for traffic engineering is outlined. the key component of this framework is a Centralize Resource Manager(CRM) responsible for monitoring and managing resources within the network and making all decisions to route／reroute traffic according to QoS requirement

• Proceedings of the IEEK Conference
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• 2000.07a
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• pp.529-532
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• 2000

This paper addresses how to be connected with end-to-end shortcut using ATM Switched Virtual Connection (SVC) in ATM-based Multi-Protocol Label Switching (MPLS) Networks. Without additionally existing ATM Ships-in-the-Night (SIN) mode, when the stream is continuously transmitted at the same destination with the lapse of determined aging time, the connection is changed with end-to-end shortcut connection using ATM signaling. An ATM direct short circuit is performed an IP and ATM effective integration. An ATM shortcut has a number of advantages, like higher throughput, shorter end-to-end delay, reduced router load, better utilization of L2 Quality of Service (QoS) capabilities, and route optimization. In particular between other MPLS domains, this can be efficiently improved the performance of networks.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1839-1842
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• 2002

Ad hoc networks are characterized by multi- hop wireless connectivity, frequently changing network topology and the need for efficient dynamic routing protocols. In this paper, we proposed a new technique to adjust the zone radius by concentrating the changes of network traffic in a particular direction, which we refer to as AZRP. We demonstrate that even though ZRP and AZRP share a similar hybrid routing behavior, the differences in the protocol mechanics can lead to significant performance differentials. We discuss the algorithm and report on the performance of AZRP scheme, and compare it to the ZRP routing protocol. Our results indicate clearly that AZRP outperforms ZRP by reducing significantly the number of route query messages. And thereby increases the efficiency of the network load.

• Proceedings of the IEEK Conference
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• 2003.11c
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• pp.105-108
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• 2003

In the next generation backbone networks based on dense-wavelength division multiplexing (DWDM), the routing and wavelength assignment with quality-of-service (QoS) recovery is essentially needed to support a wide range of communication-intensive and real-time multimedia services. This paper proposes a new dpmic routing method called as MW-MIPR (MultiWavelength-Minimum Interference Path Routing), which chooses a route that does not interfere too much with many potential future connection requests. This paper also proposes a differentiated RWA mechanisms combined with MW-MIPR algorithm to provide QoS recovery for various multimedia applications in the next generation backbone networks based on DWDM.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.223-224
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• 2007

To develop nuclear measurement system with characteristics including both re-configuration and multi-functions, we proposed a field programmable gate array (FPGA) technique to implement TDC which is more suitable for high energy Physics system. In TDC scheme, the timing resolution is more important than the count rates of channel. In order to manage pico-second resolution TDC, we used the delay components of FPGA, utilized the place and route (P&R) delay difference, and then got two ring oscillators. By setting P&R area constraints, we generated two precise ring oscillators with slightly different frequencies. Finally, we evaluated that the period difference of these two ring oscillators was about 60 pico-seconds, timing resolution of TDC.

• Bulletin of the Korean Chemical Society
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• v.30 no.11
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• pp.2532-2534
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• 2009

A facile and efficient synthetic route has been developed for the polyhydroquinoline via four component reactions of aldehydes, dimedone, ethyl acetoacetate and ammonium acetate in the presence of catalytic amount of scolecite in ethanol at 70 ${^{\circ}C}$ through Hantzsch reaction. This method gives remarkable advantages such as simple work-up procedure, environmentally friendly, inexpensive, non-toxic and recyclable catalyst, shorter reaction time along with excellent yields.

• Convergence Security Journal
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• v.5 no.1
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• pp.53-62
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• 2005

Virus protection infrastructure managementis network infrastructure management, traffic route management, virus protection zone expansion, and virus protection management for gateway area. This research paper provides a diagnosis of characteristics and weaknesses of the structure of existing virus protection infrastructure, and recommends an improved multi-level virus protection infrastructure as a measure for correcting these weaknesses. Improved virus protection infrastructure filters unnecessary mail at the gateway stage to reduce the load on server. As a result, numberof transmission accumulation decreases due to the reduction in the CPU load on the Virus wall and increase in virus treatment rate.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.277-279
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• 2005

무선 멀티 홉 네트워크는 기지국 없이 중간의 무선 단말기를 경유해서 메세지를 전송하므로 무선 단말기의 전력 상태나 이동에 따라 그 토폴로지가 자주 변한다. 따라서 목적지까지 경로를 탐색하고 유지하기 위해 효율적인 경로 탐색 기법에 대한 연구가 필요하다. 그러나 경로 탐색 과정은 경로 탐색 메세지를 네트워크 전체로 전파하는 플러딩으로 인해 네트워크의 처리율을 크게 감소시킨다. 플러딩으로 발생하는 트래픽을 억제하기 위해 제안된 선별적인 플러딩 기법 중 이웃 노드 정보에 기반 한 접근 방식은 비교적 정확하게 재전송에 필요한 노드를 선별할 수 있으나 HELLO 패킷을 주기적으로 발생시켜야 한다. 본 논문은 이웃 노드의 맥(MAC) 계층에서 발생하는 제어 메세지를 청취해서 이웃 노드의 트래픽 정보를 수집하고 이것을 이용해서 재전송에 필요한 노드를 선별하는 기법을 제안 한다.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.31-33
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• 2005

이동 ad-hoc 네트워크는 기반 망의 도움 없이 모바일 노드들로만 구성되어진 임시적인 네트워크이다. ad-hoc 네트워크를 구성한 모바일 노드들은 지속적인 전원공급이 힘들기 때문에 자신의 한정된 에너지에 의존한다. 이러한 모바일 노드의 에너지 소비를 줄이기 위해 IEEE 802.11 PSM를 적용한 다중 홉 ad-hoc 네트워크 모델에 대해서 최근 많은 연구가 이루어졌다. 다중 홉 ad-hoc 네트워크에 802.11 PSM을 적용하면 송수신에 참여하지 않는 모바일 노드들의 에너지소비를 절약하게 되어 네트워크 활동시간을 증가시키게 된다.