• Title/Summary/Keyword: Distributed Model

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Unsteady Flow Rate Measurement Based on Distributed Parameter Pipeline Model (분포정수계 관로모델을 이용한 비정상 유량계측)

  • Kim, Do-Tae;Hong, Sung-Tae
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.17 no.3
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    • pp.8-13
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    • 2008
  • The paper proposes a model-based measurement of unsteady flow rate by using distributed parameter pipeline model and the measured pressure values at two distant points along the pipeline. The distributed parameter model of hydraulic pipeline is applied with consideration of frequency dependent viscosity friction and unsteady velocity distribution at a cross section of a pipeline. By using the self-diagnostics functions of the measurement method, the validity is investigated by comparison with the measured and estimated pressure and flow rate wave forms at the halfway section on the pipeline. The results show good agreement between the estimated flow rate wave forms and theoretical those under unsteady laminar flow conditions. The method proposed here is useful in estimating unsteady flow rate through an arbitrary cross section in hydraulic pipeline and components without installing an instantaneous flowmeter.

Supply-Driven Strategies Model for Resource Management in Grid Environment (그리드 환경에서의 효율적인 자원 관리를 위한 공급-조정 전략 모델)

  • Ma Yong-Beom;Lee Jong-Sik;Cho Kyu-Cheol;Kim In-Hee;Jang Sung-Ho;Park Da-Hye
    • Proceedings of the Korea Society for Simulation Conference
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    • 2005.11a
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    • pp.65-70
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    • 2005
  • Recently, Grid is embossed as a new issue according to the need of cooperation related to distributed resources, data sharing, Interaction and so on. It focuses on sharing of large scale resources, high-performance, applications of new paradigms, which improved more than established distributed computing. Because of the environmental specificity distributed geographically and dynamic, the most important problem in grid environment is to share and to allocate distributed grid resources. This paper proposes supply-driven strategies model that is applicable for resource management in grid environment and presents a optimal resource allocation algorithm based on resource demands. Supply-driven strategies model can offer efficient resource management by transaction allocation based on user demand and provider strategy. This paper implements the supply-driven strategies model on the DEVS modeling and simulation environment and shows the efficiency and excellency of this model by comparing with established models.

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(The Design of CTS for an Editor's Composition based on Distributed Object Group Model) (분산 객체그룹 모델 하에서 편집자 직접조판을 위한 CTS 설계)

  • 유경택;주수종
    • Journal of the Korea Computer Industry Society
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    • v.3 no.8
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    • pp.1019-1026
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    • 2002
  • The Distributed system environments are developing into a structure of the opening information communication network based on object-oriented concepts and distributed technologies. Such a reason is that it can not only decrease the complexity of distributed softwares, but also support object oriented application services to distributed environments without changes of its own communication network structure. In this paper, we designed object group model, that is, an extended middleware, we developed before. The distributed environment suggested consists of the CTS server and clients. As our results, we showed the interaction procedures between/among object groups and service procedures of distributed application in given distributed system.

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A simulation system for distributed database design

  • Rho, Sangkyu
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 1995.09a
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    • pp.46-58
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    • 1995
  • Although numerous distributed database design models and solution algorithms have been developed, very few have been validated. Validation is critical to the successful application of such models to distributed database design. In this paper, we develop a simulation system for distributed database design. We then analyze and validate an average response time model using simulation. The simulation results demonstrate that the average response time model is reasonably accurate.

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Mathematical Model for File Migration and Load Balancing in Distributed Systemsc (분산 시스템에서 파일 이전과 부하 균등을 위한 수학적 모델)

  • Moon, Wonsik
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.13 no.4
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    • pp.153-162
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    • 2017
  • Advances in communication technologies and the decreasing cost of computers have made distributed computer systems an attractive alternative for satisfying the information needs of large organizations. This paper presents a distributed algorithm for performance improvement through load balancing and file migration in distributed systems. We employed a sender initiated strategy for task migration and used learning automata with several internal states for file migration. A task can be migrated according to the load information of a computer. A file is migrated to the destination processor when it is in the right boundary state. We also described an analytical model for load balancing with file migration to verify the proposed algorithm. Analytical and simulation results show that our algorithm is very well-suited for distributed system environments.

A Multimedia Presentation Model in Distributed Environments (분산 환경에서의 멀티미디어 프리젠테이션 모델)

  • 최숙영
    • Journal of Korea Society of Industrial Information Systems
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    • v.5 no.1
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    • pp.16-24
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    • 2000
  • In the distributed multimedia document system, media objects distributed over a computer network are retrieved from their sources and presented to users according to specifed temporal relations. For effective presentation, synchronization have to he supported. Furthermore, presentation in distributed environments is influenced by network band with and delay, so they have to be considered for synchronization. This paper propose a distributed multimedia presentation model that supports synchronization effectively. In this model, when media objects are transfered from servers to a client, network situation and resources are monitored and thus a feedback message for change of them is sent to sever. Then, the sever adjusts the data sending rate to control synchronization.

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Devlopment HLA DEVS-Obj-C Environment for Distributed Simulation (분산 시뮬레이션을 위한 HLA DEVS-Obj-C 환경 구축)

  • 최두진;조대호
    • Proceedings of the Korea Society for Simulation Conference
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    • 2002.11a
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    • pp.85-89
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    • 2002
  • Development of distributed simulation environment must be required in order to simulate the distributed models regionally and inter-operate with running simulations individually, Simulation based on DEVS formalism is difficult to simulate the distributed models. DEVS formalism is modeling methodology. To specify model, this formalism separates behavior and structure, therefore it is able to design complex model easily. HLA is standard framework of distribute simulation environment, It is defined to facilitate the interoperability and the reusability. RTI (Run Time Infrastructure) is software that provides common service to simulation systems and implementation of the HLA Interface Specification. Method of implementation is that modules cooperating with RTI are added to simulator on DEVS simulation environment. On the DEVS simulation environment (DEVS-Obj -C) that already developed, Highest class of abstract simulator uses service that RTI provide, then This environment is able to change DEVS model into Federate and run distribute simulation that inter-operates with the RTI. Because this distributed simulation environment includes convenience of modeling that obtains through the DEVS formalism and accompanies HLA standard, this environment make it possible to simulate with_ complex systems and heterogeneous simulations

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Catchment Responses in Time and Space to Parameter Uncertainty in Distributed Rainfall-Runoff Modeling (분포형 강우-유출 모형의 매개변수 불확실성에 대한 시.공간적 유역 응답)

  • Lee, Gi-Ha;Takara, Kaoru;Tachikawa, Yasuto;Sayama, Takahiro
    • Proceedings of the Korea Water Resources Association Conference
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    • 2009.05a
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    • pp.2215-2219
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    • 2009
  • For model calibration in rainfall-runoff modeling, streamflow data at a specific outlet is obviously required but is not sufficient to identify parameters of a model since numerous parameter combinations can result in very similar model performance measures (i.e. objective functions) and indistinguishable simulated hydrographs. This phenomenon has been called 'equifinality' due to inherent parameter uncertainty involved in rainfall-runoff modeling. This study aims to investigate catchment responses in time and space to various uncertain parameter sets in distributed rainfall-runoff modeling. Seven plausible (or behavioral) parameter sets, which guarantee identically-good model performances, were sampled using deterministic and stochastic optimization methods entitled SCE and SCEM, respectively. Then, we applied them to a computational tracer method linked with a distributed rainfall-runoff model in order to trace and visualize potential origins of streamflow at a catchment outlet. The results showed that all hydrograph simulations based on the plausible parameter sets were performed equally well while internal catchment responses to them showed totally different aspects; different parameter values led to different distributions with respect to the streamflow origins in space and time despite identical simulated hydrographs. Additional information provided by the computational tracer method may be utilized as a complementary constraint for filtering out non-physical parameter set(s) (or reducing parameter uncertainty) in distributed rainfall-runoff modeling.

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Randomized Block Size (RBS) Model for Secure Data Storage in Distributed Server

  • Sinha, Keshav;Paul, Partha;Amritanjali, Amritanjali
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.15 no.12
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    • pp.4508-4530
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    • 2021
  • Today distributed data storage service are being widely used. However lack of proper means of security makes the user data vulnerable. In this work, we propose a Randomized Block Size (RBS) model for secure data storage in distributed environments. The model work with multifold block sizes encrypted with the Chinese Remainder Theorem-based RSA (C-RSA) technique for end-to-end security of multimedia data. The proposed RBS model has a key generation phase (KGP) for constructing asymmetric keys, and a rand generation phase (RGP) for applying optimal asymmetric encryption padding (OAEP) to the original message. The experimental results obtained with text and image files show that the post encryption file size is not much affected, and data is efficiently encrypted while storing at the distributed storage server (DSS). The parameters such as ciphertext size, encryption time, and throughput have been considered for performance evaluation, whereas statistical analysis like similarity measurement, correlation coefficient, histogram, and entropy analysis uses to check image pixels deviation. The number of pixels change rate (NPCR) and unified averaged changed intensity (UACI) were used to check the strength of the proposed encryption technique. The proposed model is robust with high resilience against eavesdropping, insider attack, and chosen-plaintext attack.

Modeling for Performance Evaluation of Distributed Computer Systems (분산 컴퓨터 시스템의 성능 평가를 위한 모델연구)

  • Cho, Young-Cheol;Kwon, Wook-Hyun
    • Proceedings of the KIEE Conference
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    • 1995.11a
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    • pp.219-221
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    • 1995
  • This paper proposes a model for simulation and performance evaluation of distributed computer systems(DCS). The model is composed of operating system(OS), resource, task, environment submodel. Task Flow Graph(TFG) is suggested to describe the relation between tasks. This paper considers task response time, the scheduler's ready queue length, utilization of each resource as performance indices. The distributed system of Continuous Annealing Line(CAL) in iron process is simulated with the proposed model.

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