• Title/Summary/Keyword: Network NAT

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Circulating Current Reduction Method during Distribution Network Dynamic Reconfiguration using Active Phase Controller (능동위상제어기를 이용한 배전선로 자율 재구성 시 순환전류 감소 기법)

  • Kim, Soo-Yeon;Jeong, Da-Woom;Park, Sung-Jun;Kim, Dong-Hee
    • The Transactions of the Korean Institute of Power Electronics
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    • v.25 no.1
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    • pp.6-12
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    • 2020
  • In recent years, the demand for the distribution of energy resource has been increasing. However, the output power is limited by the stability of the distribution network. This study proposes an active distribution network that can reconfigure the distribution line using an active phase controller. The conventional distribution network has a fixed structure, whereas the proposed active distribution network has a variable structure. Therefore, the active distribution network can increase the output power of the distribution energy resource and reduce the overload of distribution line facilities. The active phase controller has two operation modes to minimize the circulating current during dynamic reconfiguration. In this study, the voltage and current control algorithms are proposed for the active phase controller. The proposed method for the active phase controller is simulated via PSIM simulation.

IPsec Support Mechanism between IPv6 Network and IPv4 Network Communication using NAT-PT (IPv6 네트워크와 IPv4 네트워크 연동을 위한 NAT-PT에서의 IPsec 지원 기법)

  • Kim Jung-Youl;Kim Dae-Sun;Hong Choong-Seon
    • Proceedings of the Korea Information Processing Society Conference
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    • 2006.05a
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    • pp.1105-1108
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    • 2006
  • IPv6의 도입으로 인해 상당기간 IPv4와 공존해야 한다. 따라서 IPv4와 IPv6간 변환 기술이 필요로 하게 되었으며 이에 여러 가지 변환 기술이 제안되어 두 프로토콜간 통신이 가능하게 되었다. 그 중 NAT-PT는 IPv6 기반의 네트워크와 IPv4 기반의 네트워크간에 직접 통신이 가능하도록 해주는 메커니즘이다. 그러나 IPsec 프로토콜의 인증 값 계산에는 TCP/UDP/ICMP 검사합 값을 포함해서 IP 주소가 사용되기 때문에 NAT-PT에는 IPsec 프로토콜을 적용할 수 없다는 보안상의 문제가 발생하였다. 따라서 본 논문에서는 NAT-PT와 IPsec의 특성을 살펴보고, NAT-PT의 보안상 문제점을 고찰하였으며 NAT-PT에 IPsec을 적용할 수 있는 방안을 제안하였다.

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Model Validation of a Fast Ethernet Controller for Performance Evaluation of Network Processors (네트워크 프로세서의 성능 예측을 위한 고속 이더넷 제어기의 상위 레벨 모델 검증)

  • Lee Myeong-jin
    • Journal of KIISE:Computing Practices and Letters
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    • v.11 no.1
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    • pp.92-99
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    • 2005
  • In this paper, we present a high-level design methodology applied on a network system-on-a-chip(SOC) using SystemC. The main target of our approach is to get optimum performance parameters for high network address translation(NAT) throughput. The Fast Ethernet media access controller(MAC) and its direct memory access(DMA) controller are modeled with SystemC in transaction level. They are calibrated through the cycle-based measurement of the operation of the real Verilog register transfer language(RTL). The NAT throughput of the model is within $\pm$10% error compared to the output of the real evaluation board. Simulation speed of the model is more than 100 times laster than the RTL. The validated models are used for intensive architecture exploration to find the performance bottleneck in the NAT router.

Experimental Analysis of NAT Detecting Algorithms (NAT 탐지 알고리즘의 실험적 분석)

  • Hwang, Sung-Hyun;Lee, Young-Seok
    • Proceedings of the Korea Information Processing Society Conference
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    • 2007.05a
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    • pp.1171-1174
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    • 2007
  • NAT는 IP주소 부족의 단기적인 해결방법으로 홈네트워크에서 널리 사용되고 있다. ISP는 트래픽 과금 등에 사용하기 위하여 NAT를 사용하는 IP 주소와 NAT에 연결된 호스트 수를 탐지하려고 한다. NAT 탐지 방법으로는 IP 패킷 헤더의 TTL 필드를 이용하는 것과 ID 필드를 이용하는 것이 있다. 본 논문에서는 NAT(Network Address Translator) 탐지를 위해 제안되어 널리 사용되는 ID 필드를 이용한 방법을 실험적으로 분석한다. 실험결과 서브넷의 계층이나 운영체제의 다양성으로 인하여 완벽하게 NAT 이용 호스트를 탐지하기 어렵다는 것을 검증하였다.

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FORECASTING THE COST AND DURATION OF SCHOOL RECONSTRUCTION PROJECTS USING ARTIFICIAL NEURAL NETWORK

  • Ying-Hua Huang ;Wei Tong Chen;Shih-Chieh Chan
    • International conference on construction engineering and project management
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    • 2005.10a
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    • pp.913-916
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    • 2005
  • This paper presents the development of Artificial Neural Network models for forecasting the cost and contract duration of school reconstruction projects to assist the planners' decision-making in the early stage of the projects. 132 schools reconstruction projects in central Taiwan, which received the most serious damage from the Chi-Chi Earthquake, were collected. The developed Artificial Neural Network prediction models demonstrate good prediction abilities with average error rates under 10% for school reconstruction projects. The analytical results indicate that the Artificial Neural Network model with back-propagation learning is a feasible method to produce accurate prediction results to assist planners' decision-making process.

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Image Processing by a Diffusion Neural Network (확산뉴런망을 이용한 영상처리)

  • Kwon, Yool;Nam, Ki-Gon;Yoon, Tae-Hoon;Kim, Jae-Chang
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.30B no.1
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    • pp.90-98
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    • 1993
  • A Gaussian is formed by diffusing a spot excitation. In this paper, a diffusion neural network model is derived from the diffusion equation. And it is shown that a difference of two Gaussians(DOG) may have the same shape as a Laplacian of Gaussian(LOG), A neural network model executing a DOG convolution by diffusing an external excitation is proposed. By this model intensity changes of image may be detected. This model may be implemented economically because each neuron has only four fixed-valued synapes.

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Network Reduction Method for Power System Transient Analysis ; Time-Domain Formulation Based On The Network Function (과도 상태 해석을 위한 계통 축약법 ; 계통 함수를 이용한 시간 영역 해석법)

  • Hong, J.H.;Kang, Y.C.;Cho, K.R.;Park, J.K.
    • Proceedings of the KIEE Conference
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    • 1991.07a
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    • pp.417-421
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    • 1991
  • In electromagnetic transient analysis, complex transmission system should be modelled in detail. But in large system, this full representation of power transmission system has a big burden in many sides such as computation time, modelling efforts, etc. It is very required, therefore, in electromagnetic transients studies to represent parts of a complete system in a reduced or an equivalent form. This paper develops the method from which system equivalents may be derived. The suggested method is of an essentially transient form, and allows travelling wave interaction between the equivalent and explicit transmission network to be modelled.

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Sleep Stage Scoring using Neural Network (신경 회로망을 사용한 수면 단계 분석)

  • Han, J.M.;Park, H.J.;Park, K.S.;Jeong, D.U.
    • Proceedings of the KOSOMBE Conference
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    • v.1997 no.05
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    • pp.395-397
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    • 1997
  • We have applied the neural network method for the neural networkmethod for the automatic scoring of the sleep stage. 17 features are extracted from the recorded EEG, EOG and EMG signals. These features are inputed to tile multilayer perceptron model. Neural network was trained with error-back propagation method. Results are compared with manual scoring of the experts, and show the possibility of application of automatic method in sleep stage scoring.

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Design and Implementation of Dynamic Peer Selection Scheme for Allocating Proxy-Server on Pure P2P Network Environments (순수 P2P 네트워크 환경에서 프락시-서버 할당을 위한 동적 피어 선정 기법 설계 및 구현)

  • Kim, Young-Jin;Kim, Moon-Jeong;Kim, Ung-Mo;Eom, Young-Ik
    • The KIPS Transactions:PartD
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    • v.10D no.1
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    • pp.153-160
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    • 2003
  • Recently, deployments of firewalls and NATs ire increasing to provide network security features or to solve the problem of public IP shortage. But, in these environments, peers in different firewall or NAT environments may get limited services because they cannot open direct communicate channels. This can be a significant problem in pure P2P environments where the peers should get or provide services by opening direct channels among themselves. In this paper, we propose a scheme for dynamically selecting a peer that fan be used as a proxy server. The proxy server supports the communication between the peers in different firewall or NAT environments. The proposed scheme is operating system independent and supports bidirectional communication among the peers in P2P environments. Additionally, the proposed scheme can distribute network traffic by dynamically allocating proxy servers to the peers that is not located in the firewall or NAT environments.