• Title/Summary/Keyword: fully distributed model

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LCT: A Lightweight Cross-domain Trust Model for the Mobile Distributed Environment

  • Liu, Zhiquan;Ma, Jianfeng;Jiang, Zhongyuan;Miao, Yinbin
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.10 no.2
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    • pp.914-934
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    • 2016
  • In the mobile distributed environment, an entity may move across domains with great frequency. How to utilize the trust information in the previous domains and quickly establish trust relationships with others in the current domain remains a challenging issue. The classic trust models do not support cross-domain and the existing cross-domain trust models are not in a fully distributed way. This paper improves the outstanding Certified Reputation (CR) model and proposes a Lightweight Cross-domain Trust (LCT) model for the mobile distributed environment in a fully distributed way. The trust certifications, in which the trust ratings contain various trust aspects with different interest preference weights, are collected and provided by the trustees. Furthermore, three factors are comprehensively considered to ease the issue of collusion attacks and make the trust certifications more accurate. Finally, a cross-domain scenario is deployed and implemented, and the comprehensive experiments and analysis are conducted. The results demonstrate that our LCT model obviously outperforms the Bayesian Network (BN) model and the CR model in our cross-domain scenario, and significantly improves the successful interaction rates of the honest entities without increasing the risks of interacting with the malicious entities.

Evaluation of Accuracy of the Physics Based Distributed Hydrologic Model Using VfloTM Model (VfloTM 모형을 이용한 물리기반의 분포형 수문모형의 정확성 평가)

  • Hong, Jun Bum;Kim, Byung Sik;Yoon, Seok Young
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.26 no.6B
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    • pp.613-622
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    • 2006
  • In this study, a fully distributed physical-based rainfall-runoff model called Vflo$^{TM}$ is applied to Junglang-cheon basin for simulating runoff. Geo-spatial data are used to parameterize the model to account for the characteristics of soils, landuse/cover, and topograph. 300m resolution DEM is used to compute slope and drainage network connectivity. Spatially distributed rainfall data is interpolated by ordinary kriging method. In this study, hydrograph from HEC-HMS and Vflo$^{TM}$ without/with calibration of parameters was compared to evaluate the accuracy of rainfall-runoff model From the results, a fully distributed physical-based rainfall-runoff model reproduce the peak time and shape of hydrograph much better than HEC-HMS.

An Integrated Surface Water-Groundwater Modeling by Using Fully Combined SWAT MODFLOW Model (완전연동형 SWAT-MODFLOW 모형을 이용한 지표수-지하수 통합 유출모의)

  • Kim, Nam Won;Chung, Il Moon;Won, Yoo Seung
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.26 no.5B
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    • pp.481-488
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    • 2006
  • This paper suggests a novel approach of integrating the quasi-distributed watershed model SWAT with the fully-distributed groundwater model MODFLOW. Since the SWAT model has semi distributed features, its groundwater components hardly considers distributed parameters such as hydraulic conductivity and storage coefficient. Generating a detailed representation of groundwater recharge, head distribution and pumping rate is equally difficult. To solve these problems, the method of exchanging the characteristics of the hydrologic response units (HRUs) in SWAT with cells in MODFLOW by fully combined manner is proposed. The linkage is completed by considering the interaction between the stream network and the aquifer to reflect boundary flow. This approach is provisionally applied to Gyungancheon basin in Korea. The application demonstrates a combined model which enables an interaction between saturated zones and channel reaches. This interaction plays an essential role in the runoff generation in the Gyungancheon basin. The comprehensive results show a wide applicability of the model which represents the temporal-spatial groundwater head distribution and recharge.

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.

Analysis of the steady state and transient characteristics of a multi-type refrigeration system (멀티형 냉동 시스템의 정상상태 및 과도응답 특성 해석)

  • Lee, Gil-Bong;Yoo, Keun-Joong;Kim, Min-Soo
    • Proceedings of the SAREK Conference
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    • 2005.11a
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    • pp.439-444
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    • 2005
  • Steady state simulation and dynamic simulation were performed to analyze the operational characteristics of a multi-type refrigeration system, Fully distributed model was adopted to simulate the steady state and transient responses of the system. The main aim was to see the effect of one indoor unit on the other unit. Numerical simulations were carried out for various operation conditions of an indoor unit - secondary fluid inlet temperature, mass flow rate and expansion valve opening. The results showed that the inlet temperature and mass flow rate of the secondary fluid of one indoor unit had minor effect on the operation of the other unit. However, the opening of the expansion valve had significant effect on the performance of the other unit.

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A distributed algorithm for the coordination of dynamic barricades composed of autonomous mobile robots

  • Lee, Geun-Ho;Defago, Xavier;Chong, Nak-Young
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.2030-2035
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    • 2005
  • In this paper, we study the distributed coordination of a set of synchronous, anonymous, memoryless mobile robots that can freely move on a two-dimensional plane but are unable to communicate directly. Based on this model, we analyze the application problem that consists in having a group of robots form a barricade line to protect from car traffic a crowd of demonstrators parading on the street. For the sake of robustness, we privilege fully decentralized solutions to the problem. In particular, we give a self-stabilizing distributed algorithm to address the problem, in this presentation

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Delineation of Groundwater and Estimation of Seepage Velocity Using High-Resolution Distributed Fiber-Optic Sensor

  • Chang, Ki-Tae;Pham, Quy-Ngoc
    • Journal of the Korean GEO-environmental Society
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    • v.16 no.6
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    • pp.39-43
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    • 2015
  • This study extends the Distributed Temperature Sensing (DTS) application to delineate the saturated zones in shallow sediment and evaluate the groundwater flow in both downward and upward directions. Dry, partially and fully saturated zones and water level in the subsurface can be recognized from this study. High resolution seepage velocity in vertical direction was estimated from the temperature data in the fully saturated zone. By a single profile, water level can be detected and seepage velocity in saturated zone can be estimated. Furthermore, thermal gradient analysis serves as a new technique to verify unsaturated and saturated zones in the subsurface. The vertical seepage velocity distribution in the recognized saturated zone is then analyzed with improvement of Bredehoeft and Papaopulos' model. This new approach provides promising potential in real-time monitoring of groundwater movement.

The audit and control of real time distributed data base system (RTDDB 시스템에서의 감사 및 통제)

  • 배청홍
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.12 no.19
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    • pp.89-98
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    • 1989
  • This research addresses the most sophisticated level of complexity of current electronic data processing(EDP) technology realtime, distributed data base(DDB) system. The major objective is to develop guidelines for the control and audit of these sophisticated system, since the control and audit philosophies, control features, and audit techniques applicable to traditional EDP systems are no longer fully appropriate for, or relevant to, these stat-of-art systems. An attempt is made to develop an internally consistent audit and control Conceptual Framework summarizing and integrating the material developed in this research, which then leads into the analysis of the control and audit model.

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Modeling, Control and Simulation of Microturbine Generator for Distributed Generation System in Smart Grid Application

  • Hong, Won-Pyo;Cho, Jae-Hoon
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.23 no.7
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    • pp.57-66
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    • 2009
  • Microturbines system (MTS) are currently being deployed as small scale on-site distributed generators for microgrids and smart grids. In order to fully exploit DG potentialities, advanced integrated controls that include power electronics facilities, communication technologies and advanced modeling are required. Significant expectations are posed on gas microturbines that can be easily installed in large commercial and public buildings. Modeling, control, simulation of microturbine generator based distributed generation system in smart grid application of buildings for both grid-connected and islanding conditions are presented. It also incorporates modeling and simulation of MT with a speed control system of the MT-permanent magnet synchronous generator to keep the speed constant with load variation. Model and simulations are performed using MATLAB, Simulink and SimPowerSystem software package. The model is built from the dynamics of each part with their interconnections. This simplified model is a useful tool for studying the various operational aspects of MT and is also applicable with building cooling, heating and power (BCHP) systems

New execution model for CAPE using multiple threads on multicore clusters

  • Do, Xuan Huyen;Ha, Viet Hai;Tran, Van Long;Renault, Eric
    • ETRI Journal
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    • v.43 no.5
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    • pp.825-834
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    • 2021
  • Based on its simplicity and user-friendly characteristics, OpenMP has become the standard model for programming on shared-memory architectures. Checkpointing-aided parallel execution (CAPE) is an approach that utilizes the discontinuous incremental checkpointing technique (DICKPT) to translate and execute OpenMP programs on distributed-memory architectures automatically. Currently, CAPE implements the OpenMP execution model by utilizing the DICKPT to distribute parallel jobs and their data to slave machines, and then collects the results after executing these distributed jobs. Although this model has been proven to be effective in terms of performance and compatibility with OpenMP on distributed-memory systems, it cannot fully exploit the capabilities of multicore processors. This paper presents a novel execution model for CAPE that utilizes two levels of parallelism. In the proposed model, we add another level of parallelism in the form of multithreaded processes on slave machines with the goal of better exploiting their multicore CPUs. Initial experimental results presented near the end of this paper demonstrate that this model provides significantly enhanced CAPE performance.