• Title, Summary, Keyword: Distributed System

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Analysis of System Impact of the Distributed Generation Using EMTP with Particular Reference to Voltage Sag

  • Yeo, Sang-Min;Kim, Chul-Hwan
    • KIEE International Transactions on Power Engineering
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    • v.4A no.3
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    • pp.122-128
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    • 2004
  • With the advent of distributed generation, power systems are fundamentally impacted in regards to stability and power quality. Distributed generation has a positive impact on system restoration following a fault, higher reliability, and mitigation of effect due to voltage sag. However, distributed generation also has a negative impact on decrease of reliability such as changes of protective device setting and mal-operation. Because bulk power systems consist of various sources and loads, it becomes complicated to analyze a power system with distributed generation. The types of distributed generation are usually classified by both rotating machinery and the inverter-based system. In this paper, distributed generation is designed by rotating machinery, and the distributed system having a model of the distributed generation is simulated using EMTP. In addition, this paper presents the simulation results according to the types of distributed generation.

Analysis of the System Impact of Distributed Generation using EMTP

  • Yeo, Sang-Min;Kim, Il-Dong;Kim, Chul-Hwan;Aggarwal, Raj
    • KIEE International Transactions on Power Engineering
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    • v.4A no.4
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    • pp.201-206
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    • 2004
  • With the advent of distributed generation, power systems in general are impacted in regards to stability and power quality. Distributed generation has positive impacts on system restoration following a fault, higher reliability, and mitigation of effect due to voltage sag. However, distributed generation also has negative impacts on the decrease of reliability such as changes of protective device setting and mal-operation. Because bulk power systems consist of various sources and loads, it is complicated to analyze power systems that have distributed generation. The types of distributed generation usually are classified as the rotating machinery system and the inverter-based system. In this paper, distributed generation is designed as a synchronous generator, and the distribution system with its distributed generation model is simulated using EMTP. In addition, this paper shows the simulation results according to the types of distributed generation

Development for a Simple Client-based Distributed Web Caching System

  • Park, Jong-Ho;Chong, Kil-To
    • 제어로봇시스템학회:학술대회논문집
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    • pp.2131-2136
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    • 2003
  • Since the number of user-requests increases dramatically on the Internet, the servers and networks can be swamped unexpectedly without any prior notice. Therefore, the end-users are waiting or refused for the responses of the contents from the originating servers. To solve this problem, it has been considered that a distributed web caching system efficiently utilizes structural elements of the network. Because a distributed web caching system uses the caches that are close to end-users on the network, it transmits the contents to users faster than the original network system. This paper proposes a simple client-based distributed web caching system(2HRCS) that client can directly perform object allocation and load balancing without an additional DNS for load balancing in CARP (Cache Array Routing Protocol) and GHS (Global Hosting System) that are the recent distributed web caching system protocol. The proposed system reduces the cost of setup and operation by removing DNS that needs to balance the load in the existing system. The system has clients with consistent hashing method, so it extends its environment to other distributed web caching system that has caches of different capacity. A distributed web caching system is composed and tested to evaluate the performance. As a result, it shows superior performance to consistent hashing system. Because this system can keep performance of the existing system and reduce costs, it has the advantage of constructing medium or small scale CDN (Contents Delivery Network).

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Development of a Distributed Road Traffic Simulation System

  • Keawmanee, T.;Seubpradit, K.;Tandayya, P.
    • Proceedings of the IEEK Conference
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    • pp.1324-1326
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    • 2002
  • This paper concerns the development of distributed interactive simulation of a road traffic system. The simulation involved models of multiple and distributed road vehicles running on different locations. The simulation system represented a traffic system as if the distributed simulation models were in the same environment. The development of the distributed road traffic simulation was based on High Level Architecture (HLA), a state-of-the-art IEEE standard for the distributed and real-time simulation. Other work concerned modeling and simulating the road vehicles and building the map database for the virtual distributed shared environment. The information used in the simulation system was only in X-axis and Y-axis as the insignificant data in the Z-axis was omitted to simplify the simulation. However, the traffic system has visualized a 3-D coordinate system. The road vehicle models were able to avoid collision. The next direction of a vehicle can be chosen from the provided choices of further paths.

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Performance of Distributed Database System built on Multicore Systems

  • Kim, Kangseok
    • Journal of Internet Computing and Services
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    • v.18 no.6
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    • pp.47-53
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    • 2017
  • Recently, huge datasets have been generating rapidly in a variety of fields. Then, there is an urgent need for technologies that will allow efficient and effective processing of huge datasets. Therefore the problems of partitioning a huge dataset effectively and alleviating the processing overhead of the partitioned data efficiently have been a critical factor for scalability and performance in distributed database system. In our work we utilized multicore servers to provide scalable service to our distributed system. The partitioning of database over multicore servers have emerged from a need for new architectural design of distributed database system from scalability and performance concerns in today's data deluge. The system allows uniform access through a web service interface to concurrently distributed databases over multicore servers, using SQMD (Single Query Multiple Database) mechanism based on publish/subscribe paradigm. We will present performance results with the distributed database system built on multicore server, which is time intensive with traditional architectures. We will also discuss future works.

On the Current Status and Future Trend of Distributed Object System (분산 객체 시스템의 현찰과 기술 전망)

  • 윤석환;김평중
    • Journal of the Korean Professional Engineers Association
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    • v.30 no.2
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    • pp.79-86
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    • 1997
  • As network has high speed and wide communication capability, users demand diverse and new software to satisfy their needs. To meet users needs, the softwares for multimedia or groupware or distributed virtual environments can communicate the widely distributed information fast and accurately. Even though the technology for this is under development, it is deficient to support the reliable computer communication. Distributed Object System aims, as the new paradigm of distributed system software development to overcome this problem, to obtain in distributed environment the easiness of development and management, expandability, reusability which object oriented technologies support by solving the complexity of communication processing through the object oriented methods. This paper aims to introduce distributed object system, its technological properties and the current status and trend of technology development related to its standardization. Additionally, with explaining the Replicated Shared Object System(RSOS) which is developed in our country as one of the distributed object systems, its future prospects and technical issues are discussed.

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Analysis of the redundant architecture for the fault-tolerance of a distributed control system

  • Moon, Hong-ju
    • Proceedings of the Korean Reliability Society Conference
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    • pp.231-238
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    • 2000
  • The distributed digital control system has many shared common components, and a single fault in the system may have effects on not a single function. Not as in an analog system, the faults in a digital system usually make discrete and abrupt changes in its output, which are hard to be expected. To cope with these situations, the fault-tolerance is an inevitable property of a distributed control system. A distributed digital control system consists of many equipments, and each equipment can be implemented by many different technologies. The fault-tolerance has to be implemented depend-ing on the overall architecture and how each equipment is implemented. The paper analyzes and compares the strategies and tactics to add the fault-tolerances in a distributed digital control system, and studies how they can be combined appropriately.

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Design and Implementation of FEP for Interfacing of Distributed Power Generation (분산전원 연계용 데이터처리장치(FEP)의 설계 및 구현)

  • Lee, Sung-Woo;Ha, Bok-Nam;Seo, In-Yong
    • Journal of Energy Engineering
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    • v.18 no.3
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    • pp.147-155
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    • 2009
  • Demand for distributed source by new and renewable energy has been gradually increasing recently. For the characteristics of distributed generation, distributed source is located near the distribution system and customers' buildings and can be operated in standalone mode or in interface mode with distribution system. When the distributed sources are interfaced with distribution system, the standard for interfacing distributed source with existing distribution system and operation manual should be updated with revisions in order to manage the distributed source effectively and operate the distribution system stably because how to operate the interfaced system is different from that of existing distribution system. In this paper, the FEP(Front End Processor) using the international standard protocol IEC-60870 for interfacing with distributed resources was designed. The designed system was verified via the test result using main control system for distributed generation and RTU(Remote Terminal Unit) for interface with distributed power generating.

Development of the Distributed Real-time Simulation System Based on HLA and DEVS (DEVS형식론을 적응한 HLA기반의 분산 실시간 시뮬레이션 시스템 개발)

  • Kim, Ho-Jeong;Lee, Jae-Hyun;Cho, Kil-Seok
    • Journal of the Korea Institute of Military Science and Technology
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    • v.9 no.3
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    • pp.25-32
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    • 2006
  • Weapon systems composed of several subsystems execute various engagement missions in distributed combat environments in cooperation with a large number of subordinate/adjacent weapon systems as well as higher echelons through tactical data links. Such distributed weapon systems require distributed real-time simulation test beds to integrate and test their operational software, analyze their performance and effects of cooperated engagement, and validate their requirement specifications. These demands present significant challenges in terms of real-time constraints, time synchronization, complexity and development cost of an engagement simulation test bed, thus necessitate the use of high-performance distributed real-time simulation architectures, and modeling and simulation techniques. In this paper, in order to meet these demands, we presented a distributed real-time simulation system based on High Level Architecture(HLA) and Discrete Event System Specification(DEVS). We validated its performance by using it as a test bed for developing the Engagement Control System(ECS) of a surface-to-air missile system. The proposed technique can be employed to design a prototype or model of engagement-level distributed real-time simulation systems.

Design of Distributed Computer Systems Using Tabu Search Method (Tabu 탐색 기법을 이용한 분산 컴퓨팅 시스템 설계)

  • Hong, Jin-Won;Kim, Jae-Yearn
    • Journal of the Society of Korea Industrial and Systems Engineering
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    • v.18 no.36
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    • pp.143-152
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    • 1995
  • This paper determines the allocation of computers and data files to minimize the sum of processing and communication costs which occur in processing jobs at each node. The problem of optimally configuring a distributed computer system belongs to the class of NP-Complete problems and the object function of this paper is nonlinear function and is hard to solve. This paper seeks the solution of distributed processing system by Tabu Search. Firstly, it presents the method of generating the starting solution proper to the distributed processing system. Secondly, it develops the method of searching neighborhood solutions. Finally, it determines the Tabu restriction appropriate to the distributed processing system. According to the experimental results, this algorithm solves a sized problems in reasonable time and is effective in the convergence of the solution. The algorithm developed in this paper is also applicable to the general allocation problems of the distributed processing system.

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