• Title/Summary/Keyword: Distributed Model

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The Selection of Optimal Distributions for Distributed Hydrological Models using Multi-criteria Calibration Techniques (다중최적화기법을 이용한 분포형 수문모형의 최적 분포형 선택)

  • Kim, Yonsoo;Kim, Taegyun
    • Journal of Wetlands Research
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    • v.22 no.1
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    • pp.15-23
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    • 2020
  • The purpose of this study is to investigate how the degree of distribution influences the calibration of snow and runoff in distributed hydrological models using a multi-criteria calibration method. The Hydrology Laboratory-Research Distributed Hydrologic Model (HL-RDHM) developed by NOAA-National Weather Service (NWS) is employed to estimate optimized parameter sets. We have 3 scenarios depended on the model complexity for estimating best parameter sets: Lumped, Semi-Distributed, and Fully-Distributed. For the case study, the Durango River Basin, Colorado is selected as a study basin to consider both snow and water balance components. This study basin is in the mountainous western U.S. area and consists of 108 Hydrologic Rainfall Analysis Project (HRAP) grid cells. 5 and 13 parameters of snow and water balance models are calibrated with the Multi-Objective Shuffled Complex Evolution Metropolis (MOSCEM) algorithm. Model calibration and validation are conducted on 4km HRAP grids with 5 years (2001-2005) meteorological data and observations. Through case study, we show that snow and streamflow simulations are improved with multiple criteria calibrations without considering model complexity. In particular, we confirm that semi- and fully distributed models are better performances than those of lumped model. In case of lumped model, the Root Mean Square Error (RMSE) values improve by 35% on snow average and 42% on runoff from a priori parameter set through multi-criteria calibrations. On the other hand, the RMSE values are improved by 40% and 43% for snow and runoff on semi- and fully-distributed models.

High Resolution Rainfall Prediction Using Distributed Computing Technology (분산 컴퓨팅 기술을 이용한 고해상도 강수량 예측)

  • Yoon, JunWeon;Song, Ui-Sung
    • Journal of Digital Contents Society
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    • v.17 no.1
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    • pp.51-57
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    • 2016
  • Distributed Computing attempts to harness a massive computing power using a great numbers of idle PCs resource distributed linked to the internet and processes a variety of applications parallel way such as bio, climate, cryptology, and astronomy. In this paper, we develop internet-distributed computing environment, so that we can analyze High Resolution Rainfall Prediction application in meteorological field. For analyze the rainfall forecast in Korea peninsula, we used QPM(Quantitative Precipitation Model) that is a mesoscale forecasting model. It needs to a lot of time to construct model which consisted of 27KM grid spacing, also the efficiency is degraded. On the other hand, based on this model it is easy to understand the distribution of rainfall calculated in accordance with the detailed topography of the area represented by a small terrain model reflecting the effects 3km radius of detail and terrain can improve the computational efficiency. The model is broken down into detailed area greater the required parallelism and increases the number of compute nodes that efficiency is increased linearly.. This model is distributed divided in two sub-grid distributed units of work to be done in the domain of $20{\times}20$ is networked computing resources.

Lateral vibration characteristics of a rotor system supported by hydrodynamic journal bearings considering the effect of a bearing width (베어링 폭의 영향을 고려한 동수압 베어링에 지지된 회전축 시스템의 횡진동 특성)

  • Han, Dong-Chul;Choi, Sang-Hyun;Kim, Woo-Jeong;Cho, Myung-Rae
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.21 no.12
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    • pp.2106-2113
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    • 1997
  • This paper presents the characteristics of lateral vibrations of rotor system supported by hydrodynamic journal bearings. Finite element model is developed for the dynamic analysis of rotor system. Hydrodynamic bearings are modeled with the distributed springs and dampers in shape of the 2nd order polynomials in the direction of bearing width. Experiments are conducted to measure the natural frequency, and experimental results are compared with the theoretical results that are calculated using the point model and distributed model. Theoretical results using the distributed model agrees better with the measured results as bearing width increases. Also, this method is applied to actual three-stage turbo blower model. Then, critical speed and forced vibration analysis are performed.

Human Tracking using Multiple-Camera-Based Global Color Model in Intelligent Space

  • Jin Tae-Seok;Hashimoto Hideki
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.6 no.1
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    • pp.39-46
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    • 2006
  • We propose an global color model based method for tracking motions of multiple human using a networked multiple-camera system in intelligent space as a human-robot coexistent system. An intelligent space is a space where many intelligent devices, such as computers and sensors(color CCD cameras for example), are distributed. Human beings can be a part of intelligent space as well. One of the main goals of intelligent space is to assist humans and to do different services for them. In order to be capable of doing that, intelligent space must be able to do different human related tasks. One of them is to identify and track multiple objects seamlessly. In the environment where many camera modules are distributed on network, it is important to identify object in order to track it, because different cameras may be needed as object moves throughout the space and intelligent space should determine the appropriate one. This paper describes appearance based unknown object tracking with the distributed vision system in intelligent space. First, we discuss how object color information is obtained and how the color appearance based model is constructed from this data. Then, we discuss the global color model based on the local color information. The process of learning within global model and the experimental results are also presented.

Design and Implementation of Client-Server Model on Virtual Real-time Interactive Distributed Simulation Environment Using Web (웹을 이용한 가상 실시간 상호작용 분산 시뮬레이션 환경엣 클라이언트-서버 모델의 설계 및 구현)

  • Jeong, Jin-Rip;U, Yeong-Je;Jeong, Chang-Seong
    • The Transactions of the Korea Information Processing Society
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    • v.6 no.1
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    • pp.57-65
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    • 1999
  • The simulation which is larger scale, complex and interactive with clients treat a lot of messages. It can be thinking more efficient distributed simulation than sequential one. The training simulation with multi-users is geographically distributed, and required high cost to operate and maintain system as increasing user requirements. The adaptation of web technology to the simulation can be a way to solves it without cost added. But dynamic web environment can causes causality error of events. This paper is concerned with client-server model, which supports interaction between distributed simulation server and web browser, and it is implemented by Java distributed object model. the result have shown that the distributed simulation is performed correctly on dynamic environment.

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A Control Model for Prototyping Virtual Factory Simulator in Computer Integrated Manufacturing Environment (통합생산환경에서의 가상공장 시물레이터 개발을 위한 제어모형)

  • Namkyu Park;Hyun Jung Lee
    • The Journal of Society for e-Business Studies
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    • v.1 no.1
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    • pp.227-247
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    • 1996
  • Presented in this paper is a control model for developing virtual factory simulator, which is being operated under the distributed environment. The control model consists of production activity plan and information flows. To incorporate elements of the characteristics of the distributed control system, we suggested a collaboration model. This model is working under the client/server architecture, and also designed for cooperative-distributed shop control(CDSC) system in order to exploit several advantages of client/server architecture. Collaboration among each agent(or client) is done through negotiation and task sharing. Based on a contract net model, the CDSC system has three kinds of agents-order agent, resource agent, and communication forwarding agent. Each agent performs shop scheduling and control through negotiation on contract net. No node in CDSC system can have authority over other node. A bidding scheme is employed far negotiation between order agent and resource agents. The CDSC system can support re-negotiation among resource agents and an algorithm for re-negotiation is also developed. Experimental results are shown to advocate the effectiveness of the CDSC system for CIM environments.

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Hybrid Parallelization for High Performance of CFD_NIMR Model (기상 모델 CFD_NIMR의 최적 성능을 위한 혼합형 병렬 프로그램 구현)

  • Kim, Min-Wook;Choi, Young-Jean;Kim, Young-Tae
    • Atmosphere
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    • v.22 no.1
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    • pp.109-115
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    • 2012
  • We parallelized the CFD_NIMR model, which is a numerical meteorological model, for best performance on both of distributed and shared memory parallel computers. This hybrid parallelization uses MPI (Message Passing Interface) to apply horizontal 2-dimensional sub-domain out of the 3-dimensional computing domain for distributed memory system, as well as uses OpenMP (Open Multi-Processing) to apply vertical 1-dimensional sub-domain for utilizing advantage of shared memory structure. We validated the parallel model with the original sequential model, and the parallel CFD_NIMR model shows efficient speedup on the distributed and shared memory system.

Runoff Analysis Using a Distributed Rainfall-Runoff Model (분포형 강우-유출 모형에 의한 유출 해석)

  • 신사철
    • Water for future
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    • v.29 no.6
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    • pp.131-139
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    • 1996
  • The main goal of this study is a rainfall-runoff analysis using atopographically-based distributed model. It consists of two parts: one is a direct runoff submodel and the other is a baseflow submodel. The direct runoff submodel is a distributed model which routed through the drainage networks with a kinematic wave model. The baseflow submodel is considered as a lumped system. This model makes it possible to take the effect of areal and temporal distribution of storm into accout.

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A study on the modeling of the inertance tube in the pulse tube refrigerator (맥동관 냉동기에서 관성관의 모델링에 관한 연구)

  • 남관우;정상권
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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    • 1999.02a
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    • pp.153-156
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    • 1999
  • In this paper, the inertance tube is modeled by the distributed impedance model. This model is verified by the analytical solutions for the long tube without the reservoir. In this model the distributed impedace effect of the inertance tube is included and mass flow rate and pressure distributions are calculated along the inertance tube for various inertance tube lengths. Mass flow rate at the inlet of the inertance tube is also calculated by this model and compared to the lumped impedance method. Mass flow rate by the distributed model shows quite different behaviors from the lumped model when the operating frequency is high and the length of the tube becomes large.

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Estimating Temporal and Spatial Variation of Sediment Transport Processes using a Distributed Catchment Model (분포형 유역모델을 이용한 유사 운반과정의 시·공간적 변동 해석)

  • Koo, Bhon K.;Cho, Jae-Heon
    • Journal of Korean Society on Water Environment
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    • v.23 no.6
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    • pp.872-880
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    • 2007
  • For effective management of sediment-related diffuse pollution, it is of utmost importance to estimate spatial variation of sediment transport processes within a catchment. A mathematical model can play a critical role in estimating sediment transport processes at the catchment scale provided that the model structure is appropriate for representing major sediment transport processes of the catchment of interest. This paper introduces a distributed catchment model River Basin Water Quality Simulator (RBWQS) and presents some results of its application to a small rural catchment in Korea. The model has been calibrated and validated for a wet period using hourly hydrographs and sediment concentrations observed at the catchment outlet. Based on the model simulation results, the spatial variation of sediment transport processes across the catchment and the effects of paddy fields and small reservoirs on hydrology and sediment transport have been analyzed at the catchment scale.