• Title/Summary/Keyword: time sequential simulation

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Skeletal Chemical Mechanisms for a Diesel Fuel Surrogate by the Directed Relation Graph(DRG) (직접 관계 그래프(DRG)를 이용한 디젤 연료의 상세 화학 반응 기구 축소화)

  • Lee, Young-J.;Huh, Kang-Y.
    • Journal of the Korean Society of Combustion
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    • v.16 no.2
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    • pp.16-22
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    • 2011
  • It is a challenging task to apply large detailed chemical mechanisms of fuel oxidation in simulation of complex combustion phenomena. There exist a few systematic methodologies to reduce detailed chemical mechanisms to smaller sizes involving less computational load. This research work concerns generation of a skeletal chemical mechanism by a directed relation graph with specified accuracy requirement. Two sequential stages for mechanism reduction are followed in a perfectly stirred reactor(PSR) for high temperature chemistry and to consider the autoignition delay time for low and high temperature chemistry. Reduction was performed for the detailed chemical mechanism of n-heptane consisting of 561 species and 2539 elementary reaction steps. Validation results show acceptable agreement for the autoignition delay time and the PSR calculation in wide parametric ranges of pressure, temperature and equivalence ratio.

(Design of GF(216) Serial Multiplier Using GF(24) and its C Language Simulation (유한체 GF(24)를 이용한 GF(216)의 직렬 곱셈기 설계와 이의 C언어 시뮬레이션)

  • 신원철;이명호
    • Journal of the Korea Society of Computer and Information
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    • v.6 no.3
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    • pp.56-63
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    • 2001
  • In this paper, The GF(216) multiplier using its subfields GF(24) is designed. This design can be used to construct a sequential logic multiplier using a bit-parallel multiplier for its subfield. A finite field serial multiplier using parallel multiplier of subfield takes a less time than serial multiplier and a smaller complexity than parallel multiplier. It has an advatageous feature. A feature between circuit complexity and delay time is compared and simulated using C language.

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Applying Parallel Processing Technique in Parallel Circuit Testing Application for improve Circuit Test Ability in Circuit manufacturing

  • Prabhavat, Sittiporn;Nilagupta, Pradondet
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.792-793
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    • 2005
  • Circuit testing process is very important in IC Manufacturing there are two ways in research for circuit testing improvement. These are ATPG Tool Design and Test simulation application. We are interested in how to use parallel technique such as one-side communication, parallel IO and dynamic Process with data partition for circuit testing improvement and we use one-side communication technique in this paper. The parallel ATPG Tool can reduce the test pattern sets of the circuit that is designed in laboratory for make sure that the fault is not occur. After that, we use result for parallel circuit test simulation to find fault between designed circuit and tested circuit. From the experiment, We use less execution time than non-parallel Process. And we can set more parameter for less test size. Previous experiment we can't do it because some parameter will affect much waste time. But in the research, if we use the best ATPG Tool can optimize to least test sets and parallel circuit testing application will not work. Because there are too little test set for circuit testing application. In this paper we use a standard sequential circuit of ISCAS89.

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Calculation Effect of GPU Parallel Programing for Planar Multibody System Dynamics (평면 다물체 동역학 해석에서 GPU 병렬 프로그래밍의 계산효과)

  • Jun, C.W.;Sohn, J.H.
    • Journal of Power System Engineering
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    • v.16 no.4
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    • pp.12-16
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    • 2012
  • In this paper, the equations of motions for planar multibody dynamics are established for considering the parallel programming based on GPU. Cartesian coordinates are used to formulate the equations of motion and implicit integration method called HHT-alpha is employed. Open chain multibody system is considered for computer simulation. CUDA toolkit is employed for establishing the GPU parallel programming. The exactness of the analysis is verified from the comparison with ADAMS. The results from parallel computing based on GPU are compared with the results from the sequential programming based on CPU in terms of calculation time. The multiple pendulum with bodies and joints is employed for the computer simulation. In the pendulum system that has 290 bodies, the parallel program indicates an improved efficiency of about 25.5 second(15.5% improvement). It is noted that the larger the size of system is, the time efficiency is better.

Combined bi-borehole technology for grouting and blocking of flowing water in karst conduits: Numerical investigation and engineering application

  • Pan, Dongdong;Zhang, Yichi;Xu, Zhenhao;Li, Haiyan;Li, Zhaofeng
    • Geomechanics and Engineering
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    • v.29 no.4
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    • pp.391-405
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    • 2022
  • A newly proposed grouting simulation method, the sequential diffusion solidification method was introduced into the numerical simulation of combined bi-borehole grouting. The traditional, critical and difficult numerical problem for the temporal and spatial variation simulation of the slurry is solved. Thus, numerical simulation of grouting and blocking of flowing water in karst conduits is realized and the mechanism understanding of the combined bi-borehole technology is promoted. The sensitivity analysis of the influence factors of combined bi-borehole grouting was investigated. Through orthogonal experiment, the influences of proximal and distal slurry properties, the initial flow velocity of the conduit and the proximal and distal slurry injection rate on the blocking efficiency are compared. The velocity variation, pressure variation and slurry deposition phenomenon were monitored, and the flow field characteristics and slurry outflow behavior were analyzed. The interaction mechanism between the proximal and distal slurries in the combined bi-borehole grouting is revealed. The results show that, under the orthogonal experiment conditions, the slurry injection rate has the greatest impact on blocking. With a constant slurry injection rate, the blocking efficiency can be increased by more than 30% when using slurry with weak time-dependent viscosity behavior in the distal borehole and slurry with strong time-dependent viscosity behavior in the proximal borehole respectively. According to the results of numerical simulation, the grouting scheme of "intercept the flow from the proximal borehole by quick-setting slurry, and grout cement slurry from the distal borehole" is put forward and successfully applied to the water inflow treatment project of China Resources Cement (Pingnan) Limestone Mine.

Performance Evaluation of OGS-FLAC Simulator for Coupled Thermal-Hydrological-Mechanical Analysis (열-수리-역학적 연계해석을 위한 OGS-FLAC 시뮬레이터의 성능 평가)

  • Park, Dohyun;Park, Chan-Hee
    • Tunnel and Underground Space
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    • v.32 no.2
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    • pp.144-159
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    • 2022
  • The present study developed a sequential approach-based numerical simulator for modeling coupled thermal-hydrological-mechanical (THM) processes in the ground and investigated the computational performance of the coupling analysis algorithm. The present sequential approach linked the two different solvers: an open-source numerical code, OpenGeoSys for solving the thermal and hydrological processes in porous media and a commercial code, FLAC3D for solving the geomechanical response of the ground. A benchmark test of the developed simulator was carried out using a THM problem where an analytical solution is given. The benchmark problem involves the coupled behavior (variations in temperature, pore pressure, stress, and deformation with time) of a fully saturated porous medium which is subject to a point heat source. The results of the analytical solution and numerical simulation were compared and the validity of the numerical simulator was investigated.

Parallel Stratified and Rotating Turbulence Simulation based on MPI (MPI 기반의 병렬 성층${\cdot}$회전 난류 시뮬레이션)

  • Kim, Byung-Uck;Yang, Sung-Bong
    • The Transactions of the Korea Information Processing Society
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    • v.7 no.1
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    • pp.57-64
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    • 2000
  • We describe a parallel implementation for the large-eddy simulation(LES) of stratified and rotating turbulence based on MPI. The parallelization strategy is specified by eliminating the tridiagonal solver with explicit method and by domain decompositions for solving the poisson equation. In this simulation we have run on CRAY-T3E under the message passing platform MPI with a various domain decomposition and the scalability of this parallel code of LES are also presented. The result shows that we can gain up to 16 times faster speed up on 64 processors with xyz-directional domain decomposition and scalable up to $128{\times}128{\times}$ which processing time is almost similar to that of $40{\times}40{\times}40$ on a single processor machine with a sequential code.

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Copper Recovery from Printed Circuit Boards Waste Sludge: Multi-step Current Electrolysis and Modeling

  • Nguyen, Huyen T.T.;Pham, Huy K.;Nguyen, Vu A.;Mai, Tung T.;Le, Hang T.T.;Hoang, Thuy T.B.
    • Journal of Electrochemical Science and Technology
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    • v.13 no.2
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    • pp.186-198
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    • 2022
  • Heavy metals recovery from Printed Circuit Boards industrial wastewater is crucial because of its cost effectiveness and environmental friendliness. In this study, a copper recovery route combining the sequential processes of acid leaching and LIX 984N extracting with an electrowinning technique from Printed Circuit Boards production's sludge was performed. The used residual sludge was originated from Hanoi Urban Environment One Member Limited Company (URENCO). The extracted solution from the printed circuit boards waste sludge containing a high copper concentration of 19.2 g/L and a small amount of iron (0.575 ppm) was used as electrolyte for the subsequent electrolysis process. By using a simulation model for multi-step current electrolysis, the reasonable current densities for an electrolysis time interval of 30 minutes were determined, to optimize the specific consumption energy for the copper recovery. The mathematical simulation model was built to calculate the important parameters of this process.

Analyzing the drought event in 2015 through statistical drought frequency analysis (통계학적 가뭄빈도분석 기법을 통한 2015년 가뭄사상에 대한 분석)

  • Lee, Taesam;Son, Chanyoung
    • Journal of Korea Water Resources Association
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    • v.49 no.3
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    • pp.177-186
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    • 2016
  • Drought is a water-related natural disaster which can be simply described as spatially and temporally sequential absence of water. However, its characteristics are very difficult to define. For this reason, the preparation and mitigation from drought events have not been successful. In the current study, we illustrated a design drought estimation approach of water resources infrastructures as well as the existing theoretical one to prepare and mitigate drought disasters. Theoretical and simulation methods were tested including three time series models such as autoregressive (AR), Gamma AR, Copula AR models. The results indicated that for South Korea region, the simulation-based method to estimate drought frequency presented better performance and all the three time series models show similar performance to each other. The current drought event occurring in South Korea was investigated with dividing South Korea into four basins as Han River, Nakdong River, Geum River, and Nakdong River basins. The results showed that two middle and north basins presented significant drought events with 3 year drought duration and around 40 year return period while the other two southern regions illustrated relatively weaker drought events.

Joint Opportunistic Spectrum Access and Optimal Power Allocation Strategies for Full Duplex Single Secondary User MIMO Cognitive Radio Network

  • Yue, Wenjing;Ren, Yapeng;Yang, Zhen;Chen, Zhi;Meng, Qingmin
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.9 no.10
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    • pp.3887-3907
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    • 2015
  • This paper introduces a full duplex single secondary user multiple-input multiple-output (FD-SSU-MIMO) cognitive radio network, where secondary user (SU) opportunistically accesses the authorized spectrum unoccupied by primary user (PU) and transmits data based on FD-MIMO mode. Then we study the network achievable average sum-rate maximization problem under sum transmit power budget constraint at SU communication nodes. In order to solve the trade-off problem between SU's sensing time and data transmission time based on opportunistic spectrum access (OSA) and the power allocation problem based on FD-MIMO transmit mode, we propose a simple trisection algorithm to obtain the optimal sensing time and apply an alternating optimization (AO) algorithm to tackle the FD-MIMO based network achievable sum-rate maximization problem. Simulation results show that our proposed sensing time optimization and AO-based optimal power allocation strategies obtain a higher achievable average sum-rate than sequential convex approximations for matrix-variable programming (SCAMP)-based power allocation for the FD transmission mode, as well as equal power allocation for the half duplex (HD) transmission mode.