• 제목/요약/키워드: Network reduction

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Analyzing the Economic Effect of Mobile Network Sharing in Korea

  • Song, Young-Keun;Zo, Hang-Jung;Lee, Sung-Joo
    • ETRI Journal
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    • 제34권3호
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    • pp.308-318
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    • 2012
  • As mobile markets in most developed countries are rapidly coming close to saturation, it is increasingly challenging to cover the cost of providing the network, as revenues are not growing. This has driven mobile operators, thus far mostly involved in facility-based competition, to turn their attention to network sharing. There exist various types of mobile network sharing (MNS), from passive to active sharing. In this paper, we propose a model, based on the supply-demand model, for evaluating the economic effects of using six types of MNS. Our study measures the economic effects of employing these six types of MNS, using actual WiBro-related data. Considering lower service price and expenditure reduction, the total economic effect from a year's worth of MNS use is estimated to be between 513 million and 689 million USD, which is equal to three to four percent of the annual revenue of Korean mobile operators. The results of this study will be used to support the establishment of a MNS policy in Korea. In addition, the results can be used as a basic model for developing various network sharing models.

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

  • 김수연;정다움;박성준;김동희
    • 전력전자학회논문지
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    • 제25권1호
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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.

신경회로망을 이용한 공압 서보실린더의 운동제어 (Motion Control of Pneumatic Servo Cylinder Using Neural Network)

  • 조승호
    • 한국정밀공학회지
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    • 제25권2호
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    • pp.140-147
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    • 2008
  • This paper describes a Neural Network based PD control scheme for motion control of pneumatic servo cylinder. Pneumatic systems have inherent nonlinearities such as compressibility of air and nonlinear frictions present in cylinder. The conventional linear controller is limited in some applications where the affection of nonlinear factor is dominant. A self-excited oscillation method is applied to derive the dynamic design parameters of linear model. Based on the parameters thus identified, a PD feedback compensator is designed first and then a neural network is incorporated. The experiments of a trajectory tracking control using the proposed control scheme are performed and a significant reduction in tracking error is achieved by comparing with those of a PD control.

상황 전파 네트워크를 이용한 확률기반 상황생성 모델 (Probability-Based Context-Generation Model with Situation Propagation Network)

  • 천성표;김성신
    • 로봇학회논문지
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    • 제4권1호
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    • pp.56-61
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    • 2009
  • A probability-based data generation is a typical context-generation method that is a not only simple and strong data generation method but also easy to update generation conditions. However, the probability-based context-generation method has been found its natural-born ambiguousness and confliction problems in generated context data. In order to compensate for the disadvantages of the probabilistic random data generation method, a situation propagation network is proposed in this paper. The situation propagating network is designed to update parameters of probability functions are included in probability-based data generation model. The proposed probability-based context-generation model generates two kinds of contexts: one is related to independent contexts, and the other is related to conditional contexts. The results of the proposed model are compared with the results of the probabilitybased model with respect to performance, reduction of ambiguity, and confliction.

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진로제어시스템을 위한 네트워크 기술연구 (A Study on Network Technology for Railway Signaling Systems)

  • 황종규;이재호;윤용기;유광균
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2004년도 춘계학술대회 논문집
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    • pp.1495-1500
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    • 2004
  • The interface link for railway signaling systems is generally point-to-point communication scheme, but there have been several efforts to apply the network technology to these interface link in overseas country. However general Ethernet scheme has several drawbacks, so this scheme cannot meet the very high reliability, safety and real-time properties. To overcome these drawbacks, there have been studies reduction and modeling of data collision probability for this ethernet at the industrial and academic world. Therefore, in this paper we analyzed describe a interface trend using network technology between railway signaling equipments and will describe a major technology and framework of a network for railway signaling system.

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구성요소가 서로 종속인 네트워크시스템의 신뢰성모형과 계산알고리즘 (Reliability Modeling and Computational Algorithm of Network Systems with Dependent Components)

  • 홍정식;이창훈
    • 한국경영과학회지
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    • 제14권1호
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    • pp.88-96
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    • 1989
  • General measure in the reliability is the k-terminal reliability, which is the probability that the specified vertices are connected by the working edges. To compute the k-terminal reliability components are usually assumed to be statistically independent. In this study the modeling and analysis of the k-terminal reliability are investigated when dependency among components is considered. As the size of the network increases, the number of the joint probability parameter to represent the dependency among components is increasing exponentially. To avoid such a difficulty the structured-event-based-reliability model (SERM) is presented. This model uses the combination of the network topology (physical representation) and reliability block diagram (logical representation). This enables us to represent the dependency among components in a network form. Computational algorithms for the k-terminal reliability in SERM are based on the factoring algorithm Two features of the ractoring algorithm are the reliability preserving reduction and the privoting edge selection strategy. The pivoting edge selction strategy is modified by two different ways to tackle the replicated edges occuring in SERM. Two algorithms are presented according to each modified pivoting strategy and illustrated by numerical example.

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배전자동화시스템의 도입이 배전계통신뢰도 향상에 기여한 사례 연구 (A Study on the Improved Efficiency of Distribution Network Reliability Using DAS)

  • 황우현;배성환;김자희;김재철
    • 전기학회논문지
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    • 제56권12호
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    • pp.2059-2064
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    • 2007
  • This paper analyzed distribution network reliability related with the increment of outages and duration time according to distribution facilities increasing. KEPCO introduced distribution automation system in 1998 which could recognize outage section by remotely monitoring the fault current and reduce the blackout area by remotely controlling distribution switches. As the result of this outage time reduction using distribution automation system, the minimum distribution automation rate was fined out in this paper on the base of analyzing diverse data and how many switches were used in distribution system to improve distribution network reliability at the situation of distribution facilities increasing. This result can be used as the model that an overseas utility company applies distribution automation system in the future.

지식경영에 대한 제 접근 : 사회적 네트워크, 자원의존 및 제도화 이론을 중심으로 (Multiple Perspectives on Knowledge Management : Social Network, Resource Dependency, and Institutionalization Theories)

  • 문계완;김기환;최석봉
    • 지식경영연구
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    • 제10권4호
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    • pp.43-60
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    • 2009
  • The current study attempts to provide the field of knowledge management with theoretical grounds from the perspective of social network, resource dependency, and institutional theory. Social network theory considers that knowledge management plays a critical role in organizational innovation through the process of knowledge sharing/creation, communication systems, and a cooperative culture and trust, whereas resource dependency perceives knowledge management as contributing to cost reduction through the process of knowledge capture/storage, database systems, and reward/incentive systems. Plus, from the perspective of institutionalization, this study discusses that organizations can not benefit from knowledge management if it is adopted with the motive of isomorphic change. Finally, this study compares and integrates the three perspectives, and discusses the implications and limitations.

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무선 센서 네트워크의 수명 향상을 위한 브로드캐스트 중복 제거 알고리즘 (Broadcast Redundancy Reduction Algorithm for Enhanced Wireless Sensor Network Lifetime)

  • 박철민;김영찬
    • 인터넷정보학회논문지
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    • 제8권4호
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    • pp.71-79
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    • 2007
  • 무선 센서 네트워크에서 통신 행위는 라우팅과 브로드캐스팅의 두 가지 형태로 특징지어질 수 있으며, 이중 브로드캐스팅은 효과적인 경로 탐색 및 패킷 전달을 위해 사용된다. 그러나 브로드캐스팅은 패킷의 중복 전달로 인한 에너지의 과소비로 네트워크의 수명을 단축시킨다. 본 논문에서는 2-hop 이웃노드 정보를 이용하는 Dominant Pruning 방식을 기반으로 중복된 포워드 노드를 제거하는 알고리즘을 제안한다. 제안한 알고리즘이 포워드 노드 수 및 네트워크 수명 면에서 우수한 성능을 나타냄을 시뮬레이션을 통해 입증하였다.

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Scalable Path Computation Flooding Approach for PCE-Based Multi-domain Networks

  • Perello, Jordi;Hernandez-Sola, Guillem;Agraz, Fernando;Spadaro, Salvatore;Comellas, Jaume
    • ETRI Journal
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    • 제32권4호
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    • pp.622-625
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    • 2010
  • In this letter, we assess the scalability of a path computation flooding (PCF) approach to compute optimal end-to-end inter-domain paths in a path computation element-based multi-domain network. PCF yields a drastically reduced network blocking probability compared to a blind per-domain path computation but introduces significant network control overhead and path computation complexity. In view of this, we introduce and compare an alternative low overhead PCF (LoPCF) solution. From the obtained results, LoPCF leads to similar blocking probabilities to PCF while exhibiting around 50% path computation complexity and network control overhead reduction.