• Title/Summary/Keyword: Universal Network

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Ad-Hoc Behavior in Opportunistic Radio

  • Mumtaz, Shahid;Marques, Paulo;Gameiro, Atilio;Rodriguez, Jonathan
    • Journal of Communications and Networks
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    • v.11 no.2
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    • pp.187-195
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    • 2009
  • The application of mathematical analysis to the study of wireless ad hoc networks has met with limited success due to the complexity of mobility, traffic models and the dynamic topology. A scenario based universal mobile telecommunications system (UMTS) time division duplex (TDD) opportunistic cellular system with an ad hoc behaviour that operates over UMTS frequency division duplex (FDD) licensed cellular network is considered. In this paper, we present a new routing metric which overall improves system performance in terms of interference and routing which operate in an ad hoc network in an opportunistic manner. Therefore we develop a simulation tool that addresses the goal of analysis and assessment of UMTS TDD opportunistic radio system with ad hoc behavior in coexistence with a UMTS FDD primary cellular networks.

국제 표준 LTE-Advanced에서 논의되고 있는 Heterogeneous Network 관련 Interference Management 기술

  • Yang, Jeong-Ryeol;Jin, Mi-Seong;Kim, Dong-In
    • Information and Communications Magazine
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    • v.28 no.8
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    • pp.10-17
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    • 2011
  • 3GPP($3^{rd}$ Generation Partnership project)는 3세대 이동통신인 UMTS(Universal Mobile Telecommunication System)의 초기 표준화 이후 HSPA(High Speed Packet Access), MBMS(Multimedia Broadcast Multicast Service) 등의 기술 개발로 UMTS시스템을 지속적으로 발전시켜 왔다. 그리고, 최근 새로운 무선 접속 기술을 기반한 LTE(Long Term Evolution)시스템에 대한 표준화를 완료하고 ITU-T(International Telecommnunications Union-Radio)의 IMT-Advanced 요구사항을 만족하는 LTE-Advanced 시스템에 대한 연구를 진행하고 있다. 한편 LTE-Advanced 표준의 목표인 무선 전송속도를 한층 더 높이고, 단위비용(cost per bit)을 더욱 낮추고, 셀 커버리지 및 용량을 확대하기 한 저출력의 피코셀, 펨토셀, 무선중계기들을 이용하여 실내외의 소규모 영역을 서비스하도록 하는 heterogeneous network에 대한 국제 표준이 활발히 논의되고 있다. 그러나 여러 셀이 혼재하는 경우 셀들간의 신호 간섭이 발생하여 사용자의 통신 품질이 크게 저하될 우려가 있다. 본 고에서는 heterogeneous network 와 관련하여 국제 표준 LTE-Advanced에서 논의되고 있는 간섭 제어 기법에 대해 소개한다.

Design of RFNN Controller for high performance Control of SynRM Drive (SynRM 드라이브의 고성능 제어를 위한 RFNN 제어기 설계)

  • Ko, Jae-Sub;Chung, Dong-Hwa
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.25 no.9
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    • pp.33-43
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    • 2011
  • Since the fuzzy neural network(FNN) is universal approximators, the development of FNN control systems have also grown rapidly to deal with non-linearities and uncertainties. However, the major drawback of the existing FNNs is that their processor is limited to static problems due to their feedforward network structure. This paper proposes the recurrent FNN(RFNN) for high performance and robust control of SynRM. RFNN is applied to speed controller for SynRM drive and model reference adaptive fuzzy controller(MFC) that combine adaptive fuzzy learning controller(AFLC) and fuzzy logic control(FLC), is applied to current controller. Also, this paper proposes speed estimation algorithm using artificial neural network(ANN). The proposed method is analyzed and compared to conventional PI and FNN controller in various operating condition such as parameter variation, steady and transient states etc.

SDR-Based Frequency Interference Emulator in the Space-Time Domain and Its Application

  • Yoon, Hyungoo;Um, Jungsun;Park, Jin-Soo;Jang, Byung-Jun
    • Journal of electromagnetic engineering and science
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    • v.18 no.1
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    • pp.58-62
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    • 2018
  • In this study, we propose a software-defined radio-based frequency interference emulator in the space-time domain. This emulator can easily model actual interference environments because of the versatile programming capability of the universal software radio peripheral and LabVIEW. As an example of an interfering network using the contention-based multiple access scheme in the time domain, we emulate a coordinated Wi-Fi network that consists of one access point and two Wi-Fi nodes. Results show that our emulator can successfully model multiple interfering signals in the Wi-Fi network and easily adjust various space-time domain parameters.

Virtual Circuit Holding Time Policies for UMTS Core Network (UMTS의 Core Nerwork에서 VC Holding Time Policy에 관한 연구)

  • 서준배;곽용원;김영진;이형우;조충호
    • Proceedings of the Korean Information Science Society Conference
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    • 2000.10c
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    • pp.117-119
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    • 2000
  • UMTS(Universal Mobile Telecommunication System)의 Core Network에서는 SGSN(Serving GPRS Support Node)과 GGSN(Gateway GPRS Support Node)사이의 전송계층을 IP-Over-ATM network을 기반으로 한다. 이는 비연결형(connectionless) IP 트래픽들을 연결지향형(connectionoriented) ATM 전송계층을 통해 전송함으로 이때 효율적인 자원관리를 위해 적절한 VC(Virtual Circuit)의 접속과 해제를 수행해야 한다. 본 논문에서는 [1]에서 제안되는 GPRS(General Packer Radio Service)의 Web 트래픽 모델에 대하여 기존의 VC의 Holding-time을 결정하는 기법인 Holding Cost Pricing Model(LRU, Mean-Variance, Adaptive policy) [2]을 GGSN과 SGSN사이의 ATM 전송계층에 적용하였다. 각각의 기법들에서 VC의 이용률(utilization)과 설정율(setup rate)을 비교함으로써 Adaptive policy 기법의 성능이 다른 기법에 비해 효율적임을 알 수 있다.

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Design of Polynomial Neural Network Classifier for Pattern Classification with Two Classes

  • Park, Byoung-Jun;Oh, Sung-Kwun;Kim, Hyun-Ki
    • Journal of Electrical Engineering and Technology
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    • v.3 no.1
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    • pp.108-114
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    • 2008
  • Polynomial networks have been known to have excellent properties as classifiers and universal approximators to the optimal Bayes classifier. In this paper, the use of polynomial neural networks is proposed for efficient implementation of the polynomial-based classifiers. The polynomial neural network is a trainable device consisting of some rules and three processes. The three processes are assumption, effect, and fuzzy inference. The assumption process is driven by fuzzy c-means and the effect processes deals with a polynomial function. A learning algorithm for the polynomial neural network is developed and its performance is compared with that of previous studies.

Adaptive Identification Method of EDM Parameters Using Neural Network (신경망을 이용한 방전 조건의 적응적 결정 방법)

  • 이건범;주상윤;왕지남
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.5
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    • pp.43-49
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    • 1998
  • Adaptive neural network approach is presented for determining Electrical Discharge Machining (EDM) parameters. Electrical Discharge Machining has been widely used with its capability of machining hard metals and tough shapes. In the past few years, EDM has been established in tool-room and large-scale production. However. in spite of it's wide application, an universal selection method of EDM parameters has not been established yet. No attempt has been tried before to suggest a logical method in determining essential machine parameters considering the machining rate and resulting surface roughness integrity. The paper presents a method, which is focusing on determining appropriate machining parameters. Depending on the electrode wear and surface roughness, an adaptive neural network is designed for providing suitable machining guideline.

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Design and Implementation of Context-Aware Computing System based on UPnP Sensor Network (UPnP 센서네트워크 기반 상황인식 시스템의 설계 및 구현)

  • Kim, Jong-Pan;Oh, Am-Suk
    • Journal of the Korea Society of Computer and Information
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    • v.15 no.11
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    • pp.185-193
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    • 2010
  • In this paper, we Provide context-aware services based on UPnP Device Module including sensor unit in existing PLC network without additional infrastructure. so existing PLC devices are controlled based on knowledge context and can be used in a ubiquitous environment. And efficient remote control and device management based on UPnP can also be provided.

Intelligent Modeling of Nuclear Power Plant Steam Generator (원자력발전소 증기발생기의 인공지능 모델링에 관한 연구)

  • Choi, Jin-Young;Lee, Jae-Gi
    • Proceedings of the KIEE Conference
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    • 1997.11a
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    • pp.675-678
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    • 1997
  • In this research we continue the study of nuclear power plant steam generator's intelligent modeling. This model represents the input-output behavior and is a preliminary stage for intelligent control. Among many intelligent models available, we study neural network models that have been proven as universal function approximators. We select multilayer perceptrons, circular backpropagation networks, piecewise linearly trained networks and recurrent neural networks as the candidates for the steam generator's intelligent models. We take the input-output pairs from steam generator's reference model and train the neural network models. We validate trained neural network models as intelligent models of steam generator.

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Multidemia Communications System on the Ingernet

  • Kim, Hyun-Joon;Lee, Huen-Joo
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 1998.06b
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    • pp.85-91
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    • 1998
  • Many of the newest network suers are gaining their fist network experience as users of the Internet. Because of the universal nature of this exciting new experience, millions of new users are driving the demand for increasingly multimedia oriented applications, especially in communication area. Since the communication via the Internet can use various media forms including audio, video and graphics, it can e very efficient communication system on the Internet, which allows Internet users to communicate, collaborate, and associate with others. Webber provides various communication services, like ACS(Audio Conference System), VCS(Video Conference System) and Virtual Space, in an integrated environment. Webber consists of Service-PUBs(Processing Unit Plug-in), which process each service, and Framework, which manages these PUPs. PUP is so highly independent of each other that it's easy to add, maintain, delete services and also optimally configure the system to user's terminal performance or network status.

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