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Статті в журналах з теми "Void search algorithm"
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Zhang, Yalong, Wei Yu, Xuan Ma, Hisakazu Ogura, and Dongfen Ye. "Multi-Objective Optimization for High-Dimensional Maximal Frequent Itemset Mining." Applied Sciences 11, no. 19 (September 26, 2021): 8971. http://dx.doi.org/10.3390/app11198971.
Повний текст джерелаАнотація:
The solution space of a frequent itemset generally presents exponential explosive growth because of the high-dimensional attributes of big data. However, the premise of the big data association rule analysis is to mine the frequent itemset in high-dimensional transaction sets. Traditional and classical algorithms such as the Apriori and FP-Growth algorithms, as well as their derivative algorithms, are unacceptable in practical big data analysis in an explosive solution space because of their huge consumption of storage space and running time. A multi-objective optimization algorithm was proposed to mine the frequent itemset of high-dimensional data. First, all frequent 2-itemsets were generated by scanning transaction sets based on which new items were added in as the objects of population evolution. Algorithms aim to search for the maximal frequent itemset to gather more non-void subsets because non-void subsets of frequent itemsets are all properties of frequent itemsets. During the operation of algorithms, lethal gene fragments in individuals were recorded and eliminated so that individuals may resurge. Finally, the set of the Pareto optimal solution of the frequent itemset was gained. All non-void subsets of these solutions were frequent itemsets, and all supersets are non-frequent itemsets. Finally, the practicability and validity of the proposed algorithm in big data were proven by experiments.
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Zhong, Deyun, Benyu Li, Tiandong Shi, Zhaopeng Li, Liguan Wang, and Lin Bi. "Repair of Voids in Multi-Labeled Triangular Mesh." Applied Sciences 11, no. 19 (October 6, 2021): 9275. http://dx.doi.org/10.3390/app11199275.
Повний текст джерелаАнотація:
In this paper, we propose a novel mesh repairing method for repairing voids from several meshes to ensure a desired topological correctness. The input to our method is several closed and manifold meshes without labels. The basic idea of the method is to search for and repair voids based on a multi-labeled mesh data structure and the idea of graph theory. We propose the judgment rules of voids between the input meshes and the method of void repairing based on the specified model priorities. It consists of three steps: (a) converting the input meshes into a multi-labeled mesh; (b) searching for quasi-voids using the breadth-first searching algorithm and determining true voids via the judgment rules of voids; (c) repairing voids by modifying mesh labels. The method can repair the voids accurately and only few invalid triangular facets are removed. In general, the method can repair meshes with one hundred thousand facets in approximately one second on very modest hardware. Moreover, it can be easily extended to process large-scale polygon models with millions of polygons. The experimental results of several data sets show the reliability and performance of the void repairing method based on the multi-labeled triangular mesh.
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Frommholz, D. "IMAGE INTERPOLATION ON THE CPU AND GPU USING LINE RUN SEQUENCES." ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences V-2-2022 (May 17, 2022): 53–60. http://dx.doi.org/10.5194/isprs-annals-v-2-2022-53-2022.
Повний текст джерелаАнотація:
Abstract. This paper describes an efficient implementation of an image interpolation algorithm based on inverse distance weighting (IDW). The time-consuming search for support pixels bordering the voids to be filled is facilitated through gapless sweeps of different directions over the image. The scanlines needed for the sweeps are constructed from a path prototype per orientation whose regular substructures get reused and shifted to produce aligned duplicates covering the entire input bitmap. The line set is followed concurrently to detect existing samples around nodata patches and compute the distance to the pixels to be newly set. Since the algorithm relies on integer line rasterization only and does not need auxiliary data structures beyond the output image and weight aggregation bitmap for intensity normalization, it will run on multi-core central and graphics processing units (CPUs and GPUs). Also, occluded support pixels of non-convex void patches are ignored, and over- or undersampling close-by and distant valid neighbors is compensated. Runtime and accuracy compared to generated IDW ground truth get evaluated for the CPU and GPU implementation of the algorithm on single-channel and multispectral bitmaps of various filling degrees.
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Chaitanya, G. V. A., and G. S. Gupta. "Liquid flow in heap leaching using the discrete liquid flow model and graph-based void search algorithm." Hydrometallurgy 221 (August 2023): 106151. http://dx.doi.org/10.1016/j.hydromet.2023.106151.
Повний текст джерела
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Zhu, Xiaoyuan, and Changhe Yuan. "Exact Algorithms for MRE Inference." Journal of Artificial Intelligence Research 55 (March 22, 2016): 653–83. http://dx.doi.org/10.1613/jair.4867.
Повний текст джерелаАнотація:
Most Relevant Explanation (MRE) is an inference task in Bayesian networks that finds the most relevant partial instantiation of target variables as an explanation for given evidence by maximizing the Generalized Bayes Factor (GBF). No exact MRE algorithm has been developed previously except exhaustive search. This paper fills the void by introducing two Breadth-First Branch-and-Bound (BFBnB) algorithms for solving MRE based on novel upper bounds of GBF. One upper bound is created by decomposing the computation of GBF using a target blanket decomposition of evidence variables. The other upper bound improves the first bound in two ways. One is to split the target blankets that are too large by converting auxiliary nodes into pseudo-targets so as to scale to large problems. The other is to perform summations instead of maximizations on some of the target variables in each target blanket. Our empirical evaluations show that the proposed BFBnB algorithms make exact MRE inference tractable in Bayesian networks that could not be solved previously.
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Okamoto, Yoshifumi, Yusuke Tominaga, Shinji Wakao, and Shuji Sato. "Topology optimization of magnetostatic shielding using multistep evolutionary algorithms with additional searches in a restricted design space." COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering 33, no. 3 (April 29, 2014): 894–913. http://dx.doi.org/10.1108/compel-10-2012-0202.
Повний текст джерелаАнотація:
Purpose – The purpose of this paper is to improve the multistep algorithm using evolutionary algorithm (EA) for the topology optimization of magnetostatic shielding, and the paper reveals the effectiveness of methodology by comparison with conventional optimization method. Furthermore, the design target is to obtain the novel shape of magnetostatic shielding. Design/methodology/approach – The EAs based on random search allow engineers to define general-purpose objects with various constraint conditions; however, many iterations are required in the FEA for the evaluation of the objective function, and it is difficult to realize a practical solution without island and void distribution. Then, the authors proposed the multistep algorithm with design space restriction, and improved the multistep algorithm in order to get better solution than the previous one. Findings – The variant model of optimized topology derived from improved multistep algorithm is defined to clarify the effectiveness of the optimized topology. The upper curvature of the inner shielding contributed to the reduction of magnetic flux density in the target domain. Research limitations/implications – Because the converged topology has many pixel element unevenness, the special smoother to remove the unevenness will play an important role for the realization of practical magnetostatic shielding. Practical implications – The optimized topology will give us useful detailed structure of magnetostatic shielding. Originality/value – First, while the conventional algorithm could not find the reasonable shape, the improved multistep optimization can capture the reasonable shape. Second, An additional search is attached to the multistep optimization procedure. It is shown that the performance of improved multistep algorithm is better than that of conventional algorithm.
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Savulionienė, Loreta, and Leonidas Sakalauskas. "Statistinis dažnų posekių paieškos algoritmas." Informacijos mokslai 58 (January 1, 2011): 126–43. http://dx.doi.org/10.15388/im.2011.0.3118.
Повний текст джерелаАнотація:
Šiuolaikinis gyvenimas susijęs su dideliais informacijos bei duomenų kiekiais. Paieška yra viena iš pagrindinių kompiuterio darbo operacijų. Paieškos tikslas – rasti dideliame duomenų kiekyje tam tikrą elementą ar elementų seką arba patvirtinti, kad jos nėra. Pagrindinis duomenų gavybos tikslas – rasti duomenyse prasmę, t. y. ryšius tarp duomenų, jų pasikartojamumą ir pan. Straipsnyje pasiūlytas naujas statistinis dažnų posekių paieškos algoritmas, eksperimentų rezultatai bei išvados. Statistinio dažnų posekių paieškos algoritmo esmė – greitai nustatyti dažnus posekius. Šis algoritmas netikrina viso rinkmenos turinio keletą kartų. Vykdant algoritmą rinkmena peržiūrima vieną kartą pagal pasirinktą tikimybę p. Šis algoritmas yra netikslus, tačiau jo vykdymo laikas daug trumpesnis nei tiksliųjų algoritmų. Statistinis dažnų posekių paieškos algoritmas gali būti taikomas struktūrų paieškos uždaviniui, kai aktualu nustatyti, koks posekis yra dažniausias, tačiau nėra labai svarbu tikslus dažnų posekių skaičius.Pagrindiniai žodžiai: posekis, kandidatinė seka, duomenų rinkinys, dažnas elementas, elementų rinkinių generavimas, hash funkcija, pirmos rūšies klaida, antros rūšies klaida, pasikliautinumo intervalas.Statistical Algorithm for Mining Frequent SequencesLoreta Savulioniene, Leonidas Sakalauskas SummaryModern life involves large amounts of data and information. Search is one of the major operations performed by a computer. Search goal is to find a sequence (element) in large amounts of data or to confirm that it does not exist. Amounts of data in databases have reached terabytes, and therefore data retrieval, analysis, rapid decision-making become increasingly complicated. Large quantities of information cover both important and void information. The main goal of data mining is to find the meaning in data, i.e. a relationship between the data, their reproducibility, etc. This technology applies to business, medicine and other areas where large amounts of information are processed and a relationship among data is detected, i.e. new information is obtained from large amounts of data. The paper proposes a new statistic algorithm for repeated sequence search. The essence of this statistic algorithm is to identify repeated sequences quickly. During the algorithm all contents of the file are not checked several times. During the algorithm, the file is checked once according to the chosen probability p. This algorithm is inaccurate, but its execution time is shorter than of the accurate algorithms.
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Fiorini, Bartolomeo, Kazuya Koyama, and Albert Izard. "Studying large-scale structure probes of modified gravity with COLA." Journal of Cosmology and Astroparticle Physics 2022, no. 12 (December 1, 2022): 028. http://dx.doi.org/10.1088/1475-7516/2022/12/028.
Повний текст джерелаАнотація:
Abstract We study the effect of two Modified Gravity (MG) theories, f(R) and nDGP, on three probes of large-scale structure, the real space power spectrum estimator Q 0, bispectrum and voids, and validate fast approximate COLA simulations against full N-body simulations for the prediction of these probes. We find that using the first three even multipoles of the redshift space power spectrum to estimate Q 0 is enough to reproduce the MG boost factors of the real space power spectrum for both halo and galaxy catalogues. By analysing the bispectrum and reduced bispectrum of Dark Matter (DM), we show that the strong MG signal present in the DM bispectrum is mainly due to the enhanced power spectrum. We warn about adopting screening approximations in simulations as this neglects non-linear contributions that can source a significant component of the MG bispectrum signal at the DM level, but we argue that this is not a problem for the bispectrum of galaxies in redshift space where the signal is dominated by the non-linear galaxy bias. Finally, we search for voids in our mock galaxy catalogues using the ZOBOV watershed algorithm. To apply a linear model for Redshift-Space Distortion (RSD) in the void-galaxy cross-correlation function, we first examine the effects of MG on the void profiles entering into the RSD model. We find relevant MG signals in the integrated-density, velocity dispersion and radial velocity profiles in the nDGP theory. Fitting the RSD model for the linear growth rate, we recover the linear theory prediction in an nDGP model, which is larger than the ΛCDM prediction at the 3σ level. In f(R) theory we cannot naively compare the results of the fit with the linear theory prediction as this is scale-dependent, but we obtain results that are consistent with the ΛCDM prediction.
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Zhao, Zhiyue, Baohui Wang, Jing Wang, Lide Fang, Xiaoting Li, Fan Wang, and Ning Zhao. "Liquid film characteristics measurement based on NIR in gas–liquid vertical annular upward flow." Measurement Science and Technology 33, no. 6 (March 10, 2022): 065014. http://dx.doi.org/10.1088/1361-6501/ac57ed.
Повний текст джерелаАнотація:
Abstract Liquid film plays a crucial role in void fraction, friction pressure drops, momentum and heat transfer in the two-phase flow. The film thickness measurement experiments of annular flow at four pressure conditions have been conducted using near-infrared sensor. The signal is processed by variational mode decomposition, whose parameters are optimized using the sparrow search algorithm. The envelope spectrum and Pearson correlation coefficient judgment criteria were adopted for signal reconstruction, and the value of the liquid film thickness is obtained. The effect (such as flow rate, pressure, entrainment, etc) of the liquid film thickness are analyzed theoretically. The characterization parameters Weg″, Wel, Nμl and X mod have been extracted and optimized, and a new average liquid film thickness correlation is proposed. The laboratory results indicate that the mean absolute percentage error of the predictive correlation is 4.35% (current data) and 12.02% (literatures data) respectively.
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Chida, Nariyoshi, and Tachio Terauchi. "Repairing Regular Expressions for Extraction." Proceedings of the ACM on Programming Languages 7, PLDI (June 6, 2023): 1633–56. http://dx.doi.org/10.1145/3591287.
Повний текст джерелаАнотація:
While synthesizing and repairing regular expressions (regexes) based on Programming-by-Examples (PBE) methods have seen rapid progress in recent years, all existing works only support synthesizing or repairing regexes for membership testing, and the support for extraction is still an open problem. This paper fills the void by proposing the first PBE-based method for synthesizing and repairing regexes for extraction. Our work supports regexes that have real-world extensions such as backreferences and lookarounds. The extensions significantly affect the PBE-based synthesis and repair problem. In fact, we show that there are unsolvable instances of the problem if the synthesized regexes are not allowed to use the extensions, i.e., there is no regex without the extensions that correctly classify the given set of examples, whereas every problem instance is solvable if the extensions are allowed. This is in stark contrast to the case for the membership where every instance is guaranteed to have a solution expressible by a pure regex without the extensions. The main contribution of the paper is an algorithm to solve the PBE-based synthesis and repair problem for extraction. Our algorithm builds on existing methods for synthesizing and repairing regexes for membership testing, i.e., the enumerative search algorithms with SMT constraint solving. However, significant extensions are needed because the SMT constraints in the previous works are based on a non-deterministic semantics of regexes. Non-deterministic semantics is sound for membership but not for extraction, because which substrings are extracted depends on the deterministic behavior of actual regex engines. To address the issue, we propose a new SMT constraint generation method that respects the deterministic behavior of regex engines. For this, we first define a novel formal semantics of an actual regex engine as a deterministic big-step operational semantics, and use it as a basis to design the new SMT constraint generation method. The key idea to simulate the determinism in the formal semantics and the constraints is to consider continuations of regex matching and use them for disambiguation. We also propose two new search space pruning techniques called approximation-by-pure-regex and approximation-by-backreferences that make use of the extraction information in the examples. We have implemented the synthesis and repair algorithm in a tool called R3 (Repairing Regex for extRaction) and evaluated it on 50 regexes that contain real-world extensions. Our evaluation shows the effectiveness of the algorithm and that our new pruning techniques substantially prune the search space.
Дисертації з теми "Void search algorithm"
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Arunchaitanya, Gadi Venkat. "A Fundamental Investigation Of Discrete Liquid, Gas And Fines Flow In A Random Packed Bed Along With Applications." Thesis, 2023. https://etd.iisc.ac.in/handle/2005/6177.
Повний текст джерелаАнотація:
The discontinuous nature of liquid flow in a random packed bed is observed in many chemical engineering and metallurgical applications like blast furnace and heap leaching. So, to model the liquid flow in these systems, the discrete nature of the liquid flow should be taken into consideration. Moreover, the effect of gas flow on the particles and liquid phase of the packed bed, taking into account the random nature of the bed and the discrete nature of the liquid, is lacking. Therefore, fundamental understanding of the liquid-solid-gas interactions in a random bed is important to improve the processes.
To understand the effect of gas-solid interaction, a slow-moving packed bed, inside the reactor, has been considered. Particles are discharged from the bottom and gas is injected laterally. The gas flow has been modelled using continuum-based fluid flow equations. It is found that gas flow is not symmetric inside the reactor due to significant variation in void sizes inside the bed. This along with gas variation also affects the residence time of each particle inside the bed.
This work is extended to the liquid flow in random bed using Discrete Liquid Flow (DLF) theory. A novel graph-based recursive Depth First Search (DFS) algorithm is developed to find the shape and size of voids in the random bed. The liquid flow behaviour has been studied in various conditions, like changing the packing size and bed height. This study confirms that the bed topology plays an important role in dictating the liquid flow behavior in a randomly packed bed. Using the DLF, DFS, the various phenomena, which occur in a multiphase flow packed bed, such as rupturing of rivulets, liquid hysteresis have been understood and explained fundamentally.
The study is further extended to heap leaching process, where the liquid flows as droplets and rivulets due to very low liquid flow rates. The liquid flow behaviour is studied in terms of tortuosity, liquid distribution, breakthrough time, contact angle etc. The study shows that heap leaching processes can be modelled in more accurate and deterministic way using DLF theory along with DFS algorithm by avoiding the uncertain experimental parameters (like bed permeability etc).
Finally, the flow behaviour of the liquid phase in a random packed bed is studied, taking into account the movement of particles due to the lateral gas and fines injection. The deviation of the liquid path due to the gas and fines drag is also captured. It is found that the deviation of the liquid path is higher for the larger particle sizes.
Частини книг з теми "Void search algorithm"
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Manrique, Daniel, Juan Rios, and Alfonso Rodriguez-Paton. "Self-Adapting Intelligent Neural Systems Using Evolutionary Techniques." In Artificial Neural Networks in Real-Life Applications, 94–115. IGI Global, 2006. http://dx.doi.org/10.4018/978-1-59140-902-1.ch005.
Повний текст джерелаАнотація:
This chapter describes genetic algorithm-based evolutionary techniques for automatically constructing intelligent neural systems. These techniques can be used to build and train multilayer perceptrons with the simplest architecture. These neural networks are usually designed using binary-coded genetic algorithms. The authors show how the basic architectures codification method, which uses an algebra-based codification, employs a shorter string length and voids illegal architectures in the search space. The networks are trained using real number codification. The morphological crossover operator is presented and compared to other important real-coded crossover operators. The purpose is to understand that the combination of all these techniques results in an evolutionary system, which self-adaptively constructs intelligent neural systems to solve a problem given as a set of training patterns. To do so, the evolutionary system is applied in laboratory tests and to a real-world problem: breast cancer diagnosis.
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"A search-ecient neighboring optimization algorithm in P2P-VoD networks." In Computing, Control, Information and Education Engineering, 523–28. CRC Press, 2015. http://dx.doi.org/10.1201/b18828-113.
Повний текст джерелаТези доповідей конференцій з теми "Void search algorithm"
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Zhou, Hong, and Chandrasekhar M. Ayyalasomayajula. "The Discrete Topology Optimization of Compliant Mechanisms." In ASME 2012 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/detc2012-70412.
Повний текст джерелаАнотація:
In the discrete topology optimization, material state is either solid or void and there is no topology uncertainty problem caused by intermediate material state. The outer corner cutting and inner corner filling strategy is introduced in this paper for the discrete topology optimization of compliant mechanisms. The design domain is discretized into quadrilateral design cells and every quadrilateral design cell is further subdivided into triangular analysis cells. All outer and inner corners are eliminated with the corner handling strategy. To make the designed compliant mechanisms safe, the local stress constraint is directly imposed on each triangular analysis cell. To circumvent the geometrical bias against the vertical design cells, the binary bit-array genetic algorithm is used to search for the optimal topology. Two topology optimization examples of compliant mechanisms are solved based on the proposed corner handling strategy and subdivision approach.
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Zhou, Hong, Nisar Ahmed, and Avinash Uttha. "The Improved Hybrid Discretization Model for the Discrete Topology Optimization of Compliant Mechanisms." In ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-86181.
Повний текст джерелаАнотація:
In the discrete topology optimization, material state is either solid or void and there is no topology uncertainty problem caused by any intermediate material state. In this paper, the improved hybrid discretization model is introduced for the discrete topology optimization of compliant mechanisms. The design domain is discretized into quadrilateral design cells and each quadrilateral design cell is further subdivided into triangular analysis cells. The dangling and redundant solid design cells are removed from topology solutions in the improved hybrid discretization model to promote the material utilization. To make the designed compliant mechanisms safe, the local stress constraint is directly imposed on each triangular analysis cell. To circumvent the geometrical bias against the vertical design cells, the binary bit-array genetic algorithm is used to search for the optimal topology. Two topology optimization examples of compliant mechanisms are solved based on the proposed improved hybrid discretization model to verify its effectiveness.
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Zhou, Hong, and Anil K. Annepu. "The Improved Quadrilateral Discretization Model for the Discrete Topology Optimization of Structures." In ASME 2012 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/detc2012-70424.
Повний текст джерелаАнотація:
In the discrete topology optimization, material state is either solid or void and there is no topology uncertainty problem caused by intermediate material state. In this paper, the improved quadrilateral discretization model is introduced for the discrete topology optimization of structures. The design domain is discretized into quadrilateral design cells and each quadrilateral design cell is further subdivided into 16 triangular analysis cells. All kinds of dangling quadrilateral design cells and sharp-corner triangular analysis cells are removed in the improved quadrilateral discretization model to promote the material utilization. To make the designed structures safe, the local stress constraint is directly imposed on each triangular analysis cell. To circumvent the geometrical bias against the vertical design cells, the binary bit-array genetic algorithm is used to search for the optimal topology. The effectiveness of the proposed improved quadrilateral discretization model and its related discrete topology optimization method is verified by two topology optimization examples of structures.
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Zhou, Hong, Venkata Krishna Perivilli, and Praveen Chilukuri. "Optimizing the Topologies of Compliant Mechanisms Using the Improved Modified Quadrilateral Discretization Model." In ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-86178.
Повний текст джерелаАнотація:
The improved modified quadrilateral discretization model for the topology optimization of compliant mechanisms is introduced in this paper. The design domain is discretized into quadrilateral design cells and each quadrilateral design cell is further subdivided into 16 triangular analysis cells. All kinds of dangling full and half quadrilateral design cells and sharp-corner triangular analysis cells are removed in the improved modified quadrilateral discretization model to enhance the material utilization. Every quadrilateral design cell or triangular analysis cell is either solid or void to implement the discrete topology optimization and eradicate topology uncertainty caused by intermediate material states. The local stress constraint is directly imposed on each triangular analysis cell to make the synthesized compliant mechanism safe. The binary bit-array genetic algorithm is used to search for the optimal topology to circumvent the geometrical bias against the vertical design cells. Two topology optimization examples of compliant mechanisms are solved based on the proposed improved modified quadrilateral discretization model to verify its effectiveness.
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Zhou, Hong, and Pranjal P. Killekar. "The Modified Quadrilateral Discretization Model for the Topology Optimization of Compliant Mechanisms." In ASME 2011 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/detc2011-47469.
Повний текст джерелаАнотація:
The modified quadrilateral discretization model for the topology optimization of compliant mechanisms is introduced in this paper. The design domain is discretized into quadrilateral design cells. There is a certain location shift between two neighboring rows of quadrilateral design cells. This modified quadrilateral discretization model allows any two contiguous design cells to share an edge whether they are in the horizontal, vertical or diagonal direction. Point connection is completely eliminated. In the proposed topology optimization method, design variables are all binary and every design cell is either solid or void to prevent grey cell problem that is usually caused by intermediate material states. Local stress constraint is directly imposed on each analysis cell to make the synthesized compliant mechanism safe. Genetic algorithm is used to search the optimum and avoid the need to select the initial guess solution and conduct sensitivity analysis. No postprocessing is needed for topology uncertainty caused by point connection or grey cell. The presented modified quadrilateral discretization model and the proposed topology optimization procedure are demonstrated by two synthesis examples of compliant mechanisms.
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Zhou, Hong, and Ravinder G. Malela. "The Discrete Topology Optimization of Structures Using the Modified Quadrilateral Discretization Model." In ASME 2012 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/detc2012-70422.
Повний текст джерелаАнотація:
The modified quadrilateral discretization model is introduced for the discrete topology optimization of structures in this paper. The design domain is discretized into quadrilateral design cells. There is a certain location shift between two neighboring rows of quadrilateral design cells. This modified quadrilateral discretization model allows any two contiguous design cells to share an edge whether they are in the horizontal, vertical or diagonal direction. Point connection is eradicated. In the proposed discrete topology optimization method of structures, design variables are all binary and every design cell is either solid or void to prevent grey cell problem that is caused by intermediate material states. Local stress constraint is directly imposed on each analysis cell to make the optimized structure safe. The binary bit-array genetic algorithm is used to search for the optimal topology to circumvent the geometrical bias against the vertical design cells. No postprocessing is needed for topology uncertainty caused by point connection or grey cell. The presented discrete topology optimization procedure is illustrated by two topology optimization examples of structures.
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Zhou, Hong. "Topology Optimization of Compliant Mechanisms Using Hybrid Discretization Model." In ASME 2010 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/detc2010-28150.
Повний текст джерелаАнотація:
Hybrid discretization model for topology optimization of compliant mechanisms is introduced in this paper. The design domain is discretized into quadrilateral design cells. Each design cell is further subdivided into triangular analysis cells. This hybrid discretization model allows any two contiguous design cells to be connected by four triangular analysis cells no matter they are in the horizontal, vertical or diagonal direction. Topological anomalies such as checkerboard patterns, diagonal element chains and de facto hinges are completely eliminated. In the proposed topology optimization method, design variables are all binary and every analysis cell is either solid or void to prevent grey cell problem that is usually caused by intermediate material states. Von Mises stress constraint is directly imposed on each analysis cell to make the synthesized compliant mechanism safe. Genetic algorithm is used to search the optimum and avoid the need to choose the initial guess solution and conduct sensitivity analysis. The obtained topology solutions require no postprocessing or interpretation, and have no point flexure, unsmooth boundary and zigzag member. The introduced hybrid discretization model and the proposed topology optimization procedure are illustrated by two classical synthesis examples in compliant mechanisms.
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Saad, Hussein, Eduardo Divo, Sandra Boetcher, Jeff Brown, and Alain Kassab. "A Robust and Efficient Thermographic NDE Tool Based on an Inverse VoF Meshless Method." In ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-36758.
Повний текст джерелаАнотація:
A novel computational tool based on the Localized Radial-basis Function (RBF) Collocation (LRC) Meshless method coupled with a Volume-of-Fluid (VoF) scheme capable of accurately and efficiently solving transient multi-dimensional heat conduction problems in composite and heterogeneous media is formulated and implemented. While the LRC Meshless method lends its inherent advantages of spectral convergence and ease of automation, the VoF scheme allows to effectively and efficiently simulate the location, size, and shape of cavities, voids, inclusions, defects, or de-attachments in the conducting media without the need to regenerate point distributions, boundaries, or interpolation matrices. To this end, the Inverse Geometric problem of Cavity Detection can be formulated as an optimization problem that minimizes an objective function that computes the deviation of measured temperatures at accessible locations to those generated by the LRC-VoF Meshless method. The LRC-VoF Meshless algorithms will be driven by an optimization code based on the Simplex Linear Programming algorithm which can efficiently search for the optimal set of design parameters (location, size, shape, etc.) within a predefined design space. Initial guesses to the search algorithm will be provided by the classical 1D semi-infinite composite analytical solution which can predict the approximate location but not the size or shape of the cavity. The LRC-VoF formulation is tested and validated through a series of controlled numerical experiments. The proposed approach will allow solving the onerous computational inverse geometric problem in a very efficient and robust manner while affording its implementation in modest computational platforms, thereby realizing the disruptive potential of the proposed multi-dimensional high-fidelity non-destructive evaluation (NDE) method in displacing the current practice of 1D-based NDE.
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Lu, Jiande, and Tangfu Yuan. "A resource quick search and locating algorithm of P2P VoD system based on skip table mechanism." In 2012 2nd International Conference on Consumer Electronics, Communications and Networks (CECNet). IEEE, 2012. http://dx.doi.org/10.1109/cecnet.2012.6201933.
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