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Optimization of a computer simulation model for packing of concrete aggregates

PARTICULATE SCIENCE AND TECHNOLOGY 2008年第4期26卷 380-395页

作者： Amirjanov, Adil Sobolev, Konstantin Univ Wisconsin Dept Civil Engn & Mech Coll Engn & Appl Sci Milwaukee WI 53201 USA Near E Univ Dept Comp Engn Nicosia Cyprus

A simulation algorithm was developed for modeling the dense packing of large assemblies of particulate materials (in the order of millions). These assemblies represent the real aggregate systems of portland cement concrete. Two variations of the algorithm are proposed: sequential packing model and particle suspension model. A developed multicell packing procedure as well as fine adjustment of the algorithm's parameters were useful to optimize the computational resources (i.e., to realize the trade-off between the memory and packing time). Some options to speed up the algorithm and to pack very large volumes of spherical entities (up to 10 million) are discussed. The described procedure resulted in a quick method for packing of large assemblies of particulate materials. The influence of model variables on the degree of packing and the corresponding distribution of particles was analyzed. Based on the simulation results, different particle size distributions of particulate materials are correlated to their packing degree. The developed algorithm generates and visualizes dense packings corresponding to concrete aggregates. These packings show a good agreement with the standard requirements and available research data. The results of the research can be applied to the optimal proportioning of concrete mixtures.

关键词： aggregates concrete mixture proportioning packing algorithm packing density particle size distribution simulation model

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Validation of Pore-Scale Simulations of Hydrodynamic Dispersion in Random Sphere packings

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Communications in Computational Physics 2013年第3期13卷 801-822页

作者： Siarhei Khirevich Alexandra Holtzel Ulrich Tallarek Department of Chemistry Philipps-Universitat MarburgHans-Meerwein-Strasse35032 MarburgGermany

We employ the lattice Boltzmann method and random walk particle tracking to simulate the time evolution of hydrodynamic dispersion in bulk,random,monodisperse,hard-sphere packings with bed porosities(interparticle void volume fractions)between the random-close and the random-loose packing *** JodreyTory and Monte Carlo-based algorithms and a systematic variation of the packing protocols we generate a portfolio of packings,whose microstructures differ in their degree of heterogeneity(DoH).Because the DoH quantifies the heterogeneity of the void space distribution in a packing,the asymptotic longitudinal dispersion coefficient calculated for the packings increases with the packings’*** investigate the influence of packing length(up to 150 d_(p),where d_(p) is the sphere diameter)and grid resolution(up to 90 nodes per d_(p))on the simulated hydrodynamic dispersion coefficient,and demonstrate that the chosen packing dimensions of 10 d_(p)×10 d_(p)×70 d_(p) and the employed grid resolution of 60 nodes per d_(p) are sufficient to observe asymptotic behavior of the dispersion coefficient and to minimize finite size *** values of the dispersion coefficients calculated for the generated packings are compared with simulated as well as experimental data from the literature and yield good to excellent agreement.

关键词： packing microstructure degree of heterogeneity packing algorithm hydrodynamic dispersion random sphere packings

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Partitioned Scheduling of Multi-Modal Mixed-Criticality Real-Time Systems on Multiprocessor Platforms 20

Partitioned Scheduling of Multi-Modal Mixed-Criticality Real...

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20th IEEE Real-Time and Embedded Technology and Applications Symposium (RTAS) as part of the Cyber-Physical Systems Week

作者： de Niz, Dionisio Phan, Linh T. X. Carnegie Mellon Univ SEI Pittsburgh PA 15213 USA Univ Penn Philadelphia PA 19104 USA

ISBN: (纸本)9781479948291

Real-time systems are becoming increasingly complex. A modern car, for example, requires a multitude of control tasks, such as braking, active suspension, and collision avoidance. These tasks not only exhibit different degrees of safety criticality but also change their criticalities as the driving mode changes. For instance, the suspension task is a critical part of the stability of the car at high speed, but it is only a comfort feature at low speed. Therefore, it is crucial to ensure timing guarantees for the system with respect to the tasks' criticalities, not only within each mode but also during mode changes. This paper presents a partitioned multi-processor scheduling scheme for multi-modal mixed-criticality real-time systems. Our scheme consists of a packing algorithm and a scheduling algorithm for each processor that take into account both mode changes and criticalities. The packing algorithm maximizes the schedulable utilization across modes using the sustained criticality of each task, which captures the overall criticality of the task across modes. The scheduling algorithm combines Rate-Monotonic scheduling with a mode transition enforcement mechanism that relies on the transitional zero-slack instants of tasks to control low-criticality tasks during mode changes, so as to preserve the schedulability of high-criticality tasks. We also present an implementation of our scheduler in the Linux operating system, as well as an experimental evaluation to illustrate its practicality. Our evaluation shows that our scheme can provide close to twice as much tolerance to overloads (ductility) compared to a mode-agnostic scheme.

关键词： Linux multiprocessing systems processor scheduling real-time systems safety-critical software Linux operating system mixed-criticality real-time systems mode transition enforcement mechanism multiprocessor platforms packing algorithm partitioned scheduling rate-monotonic scheduling safety criticality scheduling algorithm transitional zero-slack instant Interference Processor scheduling Real-time systems Road transportation Schedules Scheduling Timing real-time systems Linux scheduling of multiprocessor Multiprocessing systems safety-critical software Road transport Scheduling algorithms Religious Missions

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Traffic Reduction in Computer Networks by Agent Technology

Traffic Reduction in Computer Networks by Agent Technology

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2nd Conference on Human System Interactions

作者： Bartczak, T. Paszczynski, S. Korniak, J. Univ Informat Technol & Management Dept Distributed Syst Rzeszow Poland Univ Informat Technol & Management Rzeszow Autonomous Dept Elect & Telecommun Rzeszow Poland

ISBN: (纸本)9781424439591

The rapid growth of band requirements for data transmission in computer networks is commonly known. The growth of the network infrastructure in many countries is much slower than expected. Therefore this paper presents some introductory research towards effective and inexpensive algorithmic ways for improving the efficiency of data transmission in all network layers. In this research human behavior is also taken into account.

关键词： transmission efficiency packing algorithm data compression agent technology

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Edge-disjoint Odd Cycles in 4-edge-connected Graphs

Edge-disjoint Odd Cycles in 4-edge-connected Graphs

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29th International Symposium on Theoretical Aspects of Computer Science (STACS)

作者： Kawarabayashi, Ken-ichi Kobayashi, Yusuke Natl Inst Informat Chiyoda Ku 2-1-2 Hitotsubashi Tokyo Japan Univ Tokyo Bunkyo Ku Tokyo Japan

ISBN: (纸本)9783939897354

Finding edge-disjoint odd cycles is one of the most important problems in graph theory, graph algorithm and combinatorial optimization. In fact, it is closely related to the well-known max-cut problem. One of the difficulties of this problem is that the Erdos-Posa property does not hold for odd cycles in general. Motivated by this fact, we prove that for any positive integer k, there exists an integer f(k) satisfying the following: For any 4- edge- connected graph G = (V, E), either G has edge-disjoint k odd cycles or there exists an edge set F subset of E with |F| <= f(k) such that G-F is bipartite. We note that the 4- edge-connectivity is best possible in this statement. Similar approach can be applied to an algorithmic question. Suppose that the input graph G is a 4-edge-connected graph with n vertices. We show that, for any epsilon > 0, if k = O((log log log n)(1/2)- (epsilon)), then the edge-disjoint k odd cycle packing in G can be solved in polynomial time of n.

关键词： odd-cycles disjoint paths problem Erdos-Posa property packing algorithm 4-edge-connectivity

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A Resource-Efficient FFT/IFFT Architecture for PRIME PLC Systems 13

A Resource-Efficient FFT/IFFT Architecture for PRIME PLC Sys...

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13th IEEE International Conference on Design and Technology of Integrated Systems In Nanoscale Era (DTIS)

作者： Yang, Jing Tan, Nianxiong Tzou, Ching-Kae Harris Zhejiang Univ Coll Informat Sci & Elect Engn Hangzhou Peoples R China Hangzhou Vango Commun Inc Hangzhou Peoples R China

ISBN: (纸本)9781538652916

This paper presents a resource-efficient real-valued fast Fourier transform (RFFT) and Hermitian symmetric inverse fast Fourier transform (HSIFFT) architecture for narrowband power line communication (N-PLC) systems. The proposed architecture has high flexibility and low complexity in control, and can be easily extended to different radices and points. Based on the structure, a novel FFT/IFFT processor is designed for PRIME (PoweRline Intelligent Metering Evolution) N-PLC systems.

关键词： fast Fourier transform (FFT) real-valued signals memory-based architecture narrowband power line communication (N-PLC) packing algorithm

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Optimal algorithm for Maintaining Equipment Loading

Optimal Algorithm for Maintaining Equipment Loading

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3rd International Conference on Information Computing and Applications (ICICA 2012)

作者： Yan, Su Yan, Pengcheng Sun, Jiangsheng Zhang, Lianwu Wang, Shaoguang Ordnance Engn Coll Shijiazhuang Ordnance Tech Res Inst Shijiazhuang 050000 Peoples R China

ISBN: (纸本)9783642340406

The problem of weapon maintenance material packing is essentially a multi-constraints optimization problem. Firstly, the multi-constraints of weapon maintenance material pacicing were discussed. Secondly, the packing strategies were provided, such as space partitioning, hierarchical assembly and optimal choices. Then, the weapon maintenance material packing algorithm based on heuristics was put forward.

关键词： Weapon Maintenance Equipment Hierarchical Assembly packing algorithm

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Improved Best Fit algorithm for Billet Stacking Problem

Improved Best Fit Algorithm for Billet Stacking Problem

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International Conference on Advanced Engineering Materials and Architecture Science (ICAEMAS 2014)

作者： Dong, Guang-jing Li, Tie-ke Wang, Bai-lin Bai, Liang Xu, Shao-yun Univ Sci & Technol Beijing Dongling Sch Econ & Management Beijing 100083 Peoples R China

ISBN: (纸本)9783037859766

Aiming at billet stacking problem of the rolling mill, an IBF algorithm is used to assign the billet to the warehouse positions. The utilization of non-empty warehouse positions and shuffles are considered in the algorithm. Computational experiments demonstrate that the proposed algorithm is feasible and effective, competitive and able to find more high-quality solutions for problem instances than artificial method.

关键词： billet storage stacking problem packing algorithm best fit algorithm

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STRUCTURAL STEEL TRUCK LOADING PROBLEM: DOCUMENTING EXPERT LOADERS REASONING

STRUCTURAL STEEL TRUCK LOADING PROBLEM: DOCUMENTING EXPERT L...

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International Conference on Innovative Design and Manufacturing (ICIDM)

作者： Bolduc, Guillaume Rivest, Louis Ecole Technol Super Montreal PQ Canada

ISBN: (纸本)9781479962709

Structural steel transport is an important aspect of the construction and steel industries. It is surprising to find that structural steel packing is still done empirically by experienced workers. Therefore, this paper explores how this problem is currently dealt with in steel plants to document the loaders' reasoning, since no literature on the subject has been found. Such documentation could later help the development of an algorithm capable of planning these packings. Expert loaders' reasoning was captured through an experiment exploiting a set of miniature members representing structural steel members. Miniature members were created using additive manufacturing. This miniature set was then used to interview steel loaders and document their vocabulary, process, rules and reasoning.

关键词： Structural Steel packing Problem packing algorithm Steel Transport

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Optimal Filler Sizes for Thermal Interface Materials 18

Optimal Filler Sizes for Thermal Interface Materials

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18th IEEE InterSociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)

作者： Chowdhury, Piyas Sikka, Kamal Grill, Alfred Parekh, Dishit P. IBM Res 257 Fuller Rd Albany NY 12203 USA

ISBN: (纸本)9781728124612

The principal challenge in developing a new thermal interface material (TIM) is to co-design its micro-attributes (e.g. filler type, packing fraction, size distribution) that simultaneously ensure high effective theinial conductivity (k(eff)), low elastic modulus (E-eff) and low viscosity (eta(eff)). Today there exists little physical insight into size distributions of fillers that would optimize desired properties. These thermo-mechanical metrics follow contradicting trends if filler content is only monotonically increased. In this paper, we elucidate microstructure-property correlations vital for optimizing effective properties. First, we systematically vary filler size distributions and generate different particulate structures with a previously developed packing algorithm [1]. Then, we employ mechanistic models, based upon physics of micro scale heat/force transport, to predict k(eff), E-eff and eta(eff) of the particulate structure, thereby identifying filler size domains that optimize the desired properties.

关键词： packing algorithm Thermal Conductivity Elastic Modulus Viscosity Filler Size Distributions

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