The internal structure of composite materials is usually composed of a continuous matrix with dispersed particles. To simulate the spatial distribution of particles, the random sequential addition algorithm (RSA) is c...
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The internal structure of composite materials is usually composed of a continuous matrix with dispersed particles. To simulate the spatial distribution of particles, the random sequential addition algorithm (RSA) is commonly used. The RSA using continuous geometric function is difficult to achieve a high packing density in allowable computer time and time-consuming in the case of irregularly shaped aggregates, such as in mortar and concrete systems. In this work, a geometrical model, named as VOX, is introduced to deal with 3D irregularly shaped particles. The model applies the voxel-based overlap determination in the RSA to improve the efficiency and packing density. Also, the model is applicable to the complex boundary conditions of any geometry and provides high-quality triangle meshes valuable for finite element analysis. The mortar and concrete cubes with real-shape particles are simulated, in which the packing density is increased to 65% and 51%, respectively. The VOX model successfully packs over 150,000 real-shape aggregates into the steel cage in a full-size reinforced concrete beam model on a desktop machine. Particle shape significantly affects the packing density in the RSA and the sphericity is recommended as an indicator. The particles with higher sphericity can achieve denser packing under the same effort of attempts. Real-shape gravel used in this study behaves similarly with regular octahedron because of the similar sphericity.
This paper on the fundamental structural properties of shell-side packed columns presents an investigative study using a novel packing algorithm with the aim of validation against experimental results. The novel contr...
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This paper on the fundamental structural properties of shell-side packed columns presents an investigative study using a novel packing algorithm with the aim of validation against experimental results. The novel contribution in the predictive approach employed is the digitalisation of particles, container and packing space to generate complex life-like stochastic packing structures of particulate systems at relatively high speed (when compared to traditional vector-based approaches) which are comparable with experimentally packed beds without need for further conversion. of numerical data. A variety of packed column simulations, comprising more complex beds than often seen in the literature, namely shell-side beds with increasing complexity of internal structure and packed with spherical particles, have been undertaken and the resulting averaged numerical data compared like-for-like with experimental results with key trends reproduced. The overall aim of this work is to demonstrate the usefulness of the technique and associated computer code as an engineering aide for research, design and optimisation of the performance of packed bed systems of any geometric complexity in terms of packing structure, as well as to highlight possible areas for further development of the code. (c) 2007 Elsevier Ltd. All rights reserved.
Static Random Access Memory(SRAM) based Field Programmable Gate Array(FPGA) is widely applied in the field of aerospace, whose anti-SEU(Single Event Upset) capability becomes more and more important. To improve anti-F...
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Static Random Access Memory(SRAM) based Field Programmable Gate Array(FPGA) is widely applied in the field of aerospace, whose anti-SEU(Single Event Upset) capability becomes more and more important. To improve anti-FPGA SEU capability, the registers of the circuit netlist are tripled and divided into three categories in this study. By the packing algorithm, the registers of triple modular redundancy are loaded into different configurable logic block. At the same time, the packing algorithm considers the effect of large fan-out nets. The experimental results show that the algorithm successfully realize the packing of the register of Triple Modular Redundancy(TMR). Comparing with Timing Versatile packing(TVPACK), the algorithm in this study is able to obtain a 11% reduction of the number of the nets in critical path, and a 12% reduction of the time delay in critical path on average when TMR is not considered. Especially, some critical path delay of circuit can be improved about 33%.
Reconfigurable devices are gaining increasing attention as a viable alternative and supplementary solution to traditional CMOS technology. In this paper, we develop a more efficient 2-input look-up table (LUT) based o...
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ISBN:
(纸本)9798350387186;9798350387179
Reconfigurable devices are gaining increasing attention as a viable alternative and supplementary solution to traditional CMOS technology. In this paper, we develop a more efficient 2-input look-up table (LUT) based on the reconfigurable field-effect transistors (RFETs), leading to a smaller transistor usage and a smaller critical path delay. The cells are organized into regular matrices, known as MClusters, with a fixed interconnection pattern to replace LUTs in field-programmable gate arrays (FPGAs). To improve the efficiency of utilizing this structure, we design a SAT-based delay-aware packing algorithm to better utilize logical gates for the MCluster structure. Finally, we combine this algorithm with FPGA simulation tools to form a comprehensive benchmarking flow. A series of benchmark tests show that under the optimal design, up to 35% and 30% reduction can be achieved in delay and energy-delay product (EDP), respectively, compared to the traditional CMOS FPGAs.
Logic packing is an important procedure in an FPGA CAD flow. To get a more efficient mapping performance, a simple dual-output BLE based packing algorithm called WHUpakcer is presented. WHUpacker takes advantages of t...
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ISBN:
(纸本)9781424438686
Logic packing is an important procedure in an FPGA CAD flow. To get a more efficient mapping performance, a simple dual-output BLE based packing algorithm called WHUpakcer is presented. WHUpacker takes advantages of the dual-output BLE different from the popular one used in previous studies. This new BLE has a simpler and more refined architecture by contrast to the popular one and thus introduces a more efficient cluster mapping. Upon the experimental results on two sets of benchmarks, WHUpacker demonstrates better performance up to 12% than both P-T-Vpack and T-Vpack(1).
The Single-Sequence (SS) is simply a sequence of integers 1, 2, 3, ..., n. But it leads a unique set of ABLR-relations (above, below, left-of, right-of) that hold among n objects on a plane. Direct Relation Set (DRS) ...
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ISBN:
(纸本)0780386477
The Single-Sequence (SS) is simply a sequence of integers 1, 2, 3, ..., n. But it leads a unique set of ABLR-relations (above, below, left-of, right-of) that hold among n objects on a plane. Direct Relation Set (DRS) is to represent the direct ABLR-relations among rooms. It can be reused for any packing under the same floorplan. In this paper we analyze the relation between DRS and SS, and propose a general packing algorithm based on SS. It can update each room's coordinates on the fly. As. a feature of SS, this algorithm covers all possible placements, if our objective is in bounding-box area minimization. Experimental results showed that the proposed algorithm is pretty fast and efficient compared with the performances attained by conventional algorithms.
In the EDA process of FPGA, VTR (Verilog-to-Routing) is a commonly used open-source CAD tool in the academic community, and VPR (Versatile Place and Route) is the back-end process of VTR. The packing algorithm in VPR ...
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In recent years, many wooden houses in Japan are built using pre-cut timbers. Pre-cut timber is material for residential buildings, such as roofs, floors, and pillars, whose joints have been pre-processed. As the numb...
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In recent years, many wooden houses in Japan are built using pre-cut timbers. Pre-cut timber is material for residential buildings, such as roofs, floors, and pillars, whose joints have been pre-processed. As the number of carpenters has decreased, the demand for pre-cut timber has increased. However, since the number of pre-cut timber production factories decrease, improving the productivity of those factories is an urgent issue. From this background, we are developing an algorithm for packing formation support systems to improve packing work productivity. In this paper, we propose the algorithm for packing formation of pre-cut timbers using the iterative local search with Or-opt, and discuss numerical experiments results.
Irregular-shaped particle packing is important to simulate the cement paste microstructure. However, the efficiency of current packing models is relatively low. This study proposes a novel packing algorithm named the ...
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Irregular-shaped particle packing is important to simulate the cement paste microstructure. However, the efficiency of current packing models is relatively low. This study proposes a novel packing algorithm named the Mesh Optimization packing (MOP) model inspired by the VOX and extent overlap box (EOB) methods. The MOP model's performance in terms of accuracy, uniformity, and randomness were evaluated. Meanwhile, compared to the Anm model 2.0 and the VOX model, the MOP model excels in simulating the initial microstructure of cement paste with high cement volume fractions. When the cement volume fraction is 56.03 %, the VOX model requires 124.68 h, while the MOP model only takes 18.80 h. By adding uniform-thickness shells to irregular-shaped particles, the MOP model integrates with the HYMOSTRUC3D-E model to simulate the evolution and uniaxial stretching process of the cement paste microstructure. This innovative modelling approach offers a promising solution for future simulations of cement paste microstructure.
The dense packing of particulate assemblies is an enduring theoretical and practical problem. In spite of its apparent simplicity, this problem still remains challenging. Recent progress in the performance of computer...
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The dense packing of particulate assemblies is an enduring theoretical and practical problem. In spite of its apparent simplicity, this problem still remains challenging. Recent progress in the performance of computers boosted the development and realization of a number of effective packing algorithms. Yet, because of the complexity of the problem, many of existing methods have difficulties in handling large numbers of particles. A simulation model is proposed to overcome this. The model assumes that the centers of the spheres are randomly generated at the intersections of a cubic lattice. The largest possible spheres are packed first;subsequent spheres are limited by the set of minimum diameters, which is specified by the constraints imposed by two major parameters imitating the compaction gradient: a reduction coefficient and the number of packing trials. Importantly, the packing arrangements are not defined by the initially specified particle size distribution (as considered by many existing packing algorithms), but rather the most dense particle size distribution, along with the corresponding value of packing degree, is generated by the proposed model. Based on these criteria, a very fast algorithm was developed for simulating of the dense packing of large assemblies of particulate, spherical material (in the order of millions of particles). Using this approach, the influence of geometrical parameters and model variables on the degree of packing and the corresponding distribution of particles was studied. (C) 2004 Elsevier B.V. All rights reserved.
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