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A Modified Tabu Search algorithm to Solve Vehicle Routing Problem

电脑学刊 2018年第3期29卷 197-209页

作者： Qinhong Fu Kang Zhou Huaqing Qi Falin Jiang

A modified tabu search algorithm (TS) is designed to enhance the efficiency of TS, the relevant data structures are redesigned; in order to solve the precision of TS, the algorithm flow is adjusted under the premise of retaining the essence of TS, besides, and the modified algorithm uses three neighborhood functions to generate candidate solutions sorted to better the precision and efficiency of VRP. Comparing the efficiency with the classical TS, the computation time of the modified algorithm is obviously shortened. Mean-while, Solomon instance of different scales are tested, the result shows that the optimum solution obtained by the modified algorithm is better than the classical TS, the search time is also greatly shorten and the deviation rate is further reduced. Furthermore, comparing the experiment result with Artificial Bee Colony algorithm (ABC), the modified algorithm that can find the optimum solution is better than ABC, in addition, com-pared with the ACO algorithm, the result is not much better than the ACO algorithm, but the computing time is nearly half of the reduction, which explains TS to solve vehicle routing problem has a certain advantage and proves the effectiveness and efficiency of the modified algorithm.

关键词： algorithm efficiency data structure tabu search VRP

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Rapid and accurate fatigue assessment by an efficient critical plane algorithm: application to a FSAE car rear upright

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Procedia Structural Integrity 2023年 47卷 749-756页

作者： A. Chiocca M. Sgamma F. Frendo F. Bucchi

The topic of material fatigue is widely discussed and researched in both scientific and industrial communities. Fatigue damage remains a significant issue for both metallic and non-metallic components, leading to unforeseen failures of in-service parts. Critical plane methods are particularly recommended in case of multiaxial fatigue assessment and have gained relevance as they allow for the identification of the component's critical location and early crack propagation. However, the standard method for calculating critical plane factors is time-consuming, utilizing nested for/end loops and, for that, is mainly applied in a research context, or when critical regions are already known. In many cases, the critical area of a component cannot be identified due to complex geometries and loads or time constraints. This becomes particularly relevant after topological optimization of components and, more generally, in lightweight design. An efficient algorithm for critical plane factors evaluation have been recently proposed by the authors. The algorithm applies to all critical plane factors that require the maximization of a specific parameter based on stress and strain components or a combination of them. The methodology is based on tensor invariants and coordinates transformation law. This paper presents and validate the proposed methodology through an automotive case study: the new algorithm was tested on a rear upright of a FSAE car, having complex geometry, subjected to non-proportional loading conditions. The efficient algorithm showed a significant reduction in computation time compared to the (blind search-for) standard plane scanning method, without any loss in solution accuracy.

关键词： critical plane multiaxial fatigue fatigue assessment computational cost algorithm efficiency finite element analysis upright lightweight design

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Numerical Solution of Diffusion Models in Biomedical Imaging on Multicore Processors

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INTERNATIONAL JOURNAL OF BIOMEDICAL IMAGING 2011年第unknown期2011卷 680765-680780页

作者： D'Amore, Luisa Casaburi, Daniela Marcellino, Livia Murli, Almerico Univ Naples Federico II Complesso Univ MS AngeloVia Cintia I-80126 Naples Italy SPACI I-80126 Naples Italy Univ Naples Parthenope Ctr Direzionale I-80143 Naples Italy

In this paper, we consider nonlinear partial differential equations (PDEs) of diffusion/advection type underlying most problems in image analysis. As case study, we address the segmentation of medical structures. We perform a comparative study of numerical algorithms arising from using the semi-implicit and the fully implicit discretization schemes. Comparison criteria take into account both the accuracy and the efficiency of the algorithms. As measure of accuracy, we consider the Hausdorff distance and the residuals of numerical solvers, while asmeasure of efficiency we consider convergence history, execution time, speedup, and parallel efficiency. This analysis is carried out in a multicore-based parallel computing environment.

关键词： PROCESSOR Multi-core processors algorithms NUMERICAL SOLUTION DIFFUSION MODELS Numerical algorithm efficiency image analysis

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How many critical planes? A perspective insight into structural integrity

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Procedia Structural Integrity 2024年 58卷 35-41页

作者： A. Chiocca M. Sgamma F. Frendo

The topic of material fatigue is a subject extensively investigated within both scientific and industrial worlds. Fatigue-induced damage remains a critical concern for a variety of components, encompassing both metallic and non-metallic materials, often leading to unexpected failures during their operational lifecycle. In cases necessitating the assessment of multiaxial fatigue, critical plane methodologies have emerged as a valuable approach. These methodologies offer the means to pinpoint the component's critical regions and anticipate early-stage crack propagation. Nevertheless, the conventional technique (i.e., plane scanning method) for computing critical plane factors is a time-intensive process, reliant on nested iterations, predominantly suited for research purposes. In numerous cases, where the critical area within a component is unknown in advance (i.e., primarily due to complex geometries and loading conditions) the method proves impractical. Furthermore, the plane scanning method does not provide a deep comprehension of the critical plane concept; indeed, it is just a numerical artifice for calculating stress and strain quantities on different planes. Recently, the authors introduced an efficient algorithm for evaluating critical plane factors. This algorithm is based on a closed form solution and is applicable to all instances where the maximization of a specific parameter, based on stress or strain components, is required. The methodology relies on tensor invariants and coordinates transformation principles thus enhancing the investigation of various critical plane methods. The paper addresses two formulations of the Fatemi-Socie critical plane factor and discusses how the number of critical planes depend on the loading conditions the component is subjected to. By the use of a closed form solution a deep insight of critical planes orientation can be achieved.

关键词： critical plane multiaxial fatigue fatigue assessment computational cost algorithm efficiency finite element analysis

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A hybrid algorithm for the load flow analysis of VSC-HVDC systems based on 1+√2 order Newton-Raphson and simplified Newton

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INTERNATIONAL JOURNAL OF ELECTRICAL POWER & ENERGY SYSTEMS 2020年第0期118卷 105828-000页

作者： Wei, Yanfang Li, Qiankun Liu, Kang-Zhi Wang, Peng Zeng, Zhihui Wang, Xiaowei Henan Polytech Univ Sch Elect Engn & Automat Jiaozuo 454000 Henan Peoples R China Chiba Univ Dept Elect & Elect Engn Chiba 2638522 Japan State Grid Henan Elect Power Res Inst Zhengzhou 454052 Peoples R China Xi An Jiao Tong Univ Sch Elect Engn Xian 710049 Peoples R China

With the rapid increase of multi-terminal and multi-infeed VSC-HVDC lines, the dimension and scale of AC/DC system equation and Jacobian matrix (JM) increase sharply, which makes the load flow (LF) analysis very complicated. In this paper, a new hybrid method is proposed to address this issue. This hybrid algorithm is composed of a 1 + root 2 order Newton-Raphson (NR) method and a simplified Newton (SN) method. Specifically, the 1 + root 2 order NR method is executed up to a preset number of iterations first, then the algorithm is switched to the SN until the system accuracy is met. A good compromise between the solution accuracy and computation burden can be achieved once a suitable iteration number is preset. To this end, a unified iterative form suitable for solving the LF of AC/DC systems with VSC-HVDC is derived in detail: a dimension reduction treatment is proposed to solve the problem of increasing dimension of JM;a rule of thumb is provided for the determination of the iteration number of 1 + root 2 order NR. Then, the proposed hybrid method is validated on the modified IEEE-14, 30, 57 and 118 test systems. Comparisons and analyses are made for numerous scenarios, including the basic test of LF, different control modes and control objectives, influence of active and reactive powers on VSC parameters, algorithm performance under various initial states and heavy loading, etc. Compared with Newton and 1 + root 2 order NR methods, the hybrid method shows a significantly shortened convergence time, 30% of 1 + root 2 order NR and 47% of Newton on average.

关键词： Voltage source converter AC/DC system Hybrid high-order Newton method Load flow algorithm efficiency

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Efficient variable selection algorithm adopting variance inflated resampling weight vector into model population analysis

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JOURNAL OF CHEMOMETRICS 2019年第2期33卷 e3099-e3099页

作者： Mahanty, Biswanath Karunya Inst Technol & Sci Dept Biotechnol Coimbatore 641114 Tamil Nadu India

Variable iterative space shrinkage approach (VISSA) is an important variable selection algorithm known for its improved accuracy and outcome stability in partial least squares (PLS) regression models. However, time efficiency of VISSA is not very promising. In this work, three strategies to inflate the variance of resampling weight vector (RWV) have been proposed to accelerate the space shrinkage in VISSA. The original RWV (ie, average binary frequency of variables) is replaced with average of unit normalized regression coefficients (UNRC), fitness normalized regression coefficients (FNRC), or logarithmically transformed regression coefficients (LTRC) of selected PLS sub-models. Although prediction efficiencies for UNRC and FNRC are marginally inferior to the original binary-weight VISSA, the stability of retained variables and remarkable improvements in algorithm speed is evident for relatively large size NIR data set (700 variables). LTRC with moderate degree of RWV variance inflation is indisputably a better choice. Chimeric algorithm, incorporating UNRC, FNRC, or LTRC in first round of original VISSA, maintained the model fitness per se while significantly improving time efficiency. With small dimensional NIR data set (100 variables), proposed weighting schemes have no additional advantage over original VISSA implementation.

关键词： algorithm efficiency binary matrix sampling inflated variance variable selection VISSA

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On the Computation of the Efficient Frontier of the Portfolio Selection Problem

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JOURNAL OF APPLIED MATHEMATICS 2012年第unknown期2012卷 105616-1-105616-25页

作者： Calvo, Clara Ivorra, Carlos Liern, Vicente Univ Valencia Dept Matemat Econ & Empresa Valencia Spain

An easy-to-use procedure is presented for improving the e-constraint method for computing the efficient frontier of the portfolio selection problem endowed with additional cardinality and semicontinuous variable constraints. The proposed method provides not only a numerical plotting of the frontier but also an analytical description of it, including the explicit equations of the arcs of parabola it comprises and the change points between them. This information is useful for performing a sensitivity analysis as well as for providing additional criteria to the investor in order to select an efficient portfolio. Computational results are provided to test the efficiency of the algorithm and to illustrate its applications. The procedure has been implemented in Mathematica.

关键词： Frontier Parabolas mathematics computing Sensitivity analysis algorithm efficiency

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Solution of an Integral-Differential Equation Arising in Oscillating Magnetic Fields Using Local Polynomial Regression

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ADVANCES IN MECHANICAL ENGINEERING 2014年第Pt.2期000卷 107-107页

作者： Li, Fenglan Yan, Tianshun Su, Liyun Lib Chongqing Univ Technol Chongqing 400054 Peoples R China Chongqing Univ Technol Sch Math & Stat Chongqing 400054 Peoples R China

An integrodifferential equation which describes the charged particle motion for certain configurations of oscillating magnetic fields is considered. The local polynomial regression method (LPR) is used to solve this equation. The reliability of this method and the reduction in the size of computational domain give this method a wider applicability. Several representative examples are given to reconfirm the efficiency of these algorithms. The results of applying this theory to the integro-differential equation with time-periodic coefficients reveal that LPR method possesses very high accuracy, adaptability, and efficiency.

关键词： PARTICLE MOTION magnetic field Polynomial oscillating magnetic field POLYNOMIAL REGRESSION integro-differential equations Size reduction algorithm efficiency

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Towards a Refined Heuristic Evaluation: Incorporating Hierarchical Analysis for Weighted Usability Assessment

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BIG DATA AND COGNITIVE COMPUTING 2024年第6期8卷 69页

作者： Talero-Sarmiento, Leonardo Gonzalez-Capdevila, Marc Granollers, Antoni Lamos-Diaz, Henry Pistili-Rodrigues, Karine Univ Autonoma Bucaramanga Ingn Ind Bucaramanga 680003 Colombia Ctr Univ Facens Programa Inst Bolsas Iniciacao Desenvolvimento Tec BR-18087125 Sao Paulo Brazil Univ Lleida Polytech Sch Engn Informat & Disseny Digital Lleida 25002 Spain Univ Ind Santander Ingn Ind Bucaramanga 680002 Colombia

This study explores the implementation of the analytic hierarchy process in usability evaluations, specifically focusing on user interface assessment during software development phases. Addressing the challenge of diverse and unstandardized evaluation methodologies, our research develops and applies a tailored algorithm that simplifies heuristic prioritization. This novel method combines the analytic hierarchy process framework with a bespoke algorithm that leverages transitive properties for efficient pairwise comparisons, significantly reducing the evaluative workload. The algorithm is designed to facilitate the estimation of heuristic relevance regardless of the number of items per heuristic or the item scale, thereby streamlining the evaluation process. Rigorous simulation testing of this tailored algorithm is complemented by its empirical application, where seven usability experts evaluate a web interface. This practical implementation demonstrates our method's ability to decrease the necessary comparisons and simplify the complexity and workload associated with the traditional prioritization process. Additionally, it improves the accuracy and relevance of the user interface usability heuristic testing results. By prioritizing heuristics based on their importance as determined by the Usability Testing Leader-rather than merely depending on the number of items, scale, or heuristics-our approach ensures that evaluations focus on the most critical usability aspects from the start. The findings from this study highlight the importance of expert-driven evaluations for gaining a thorough understanding of heuristic UI assessment, offering a wider perspective than user-perception-based methods like the questionnaire approach. Our research contributes to advancing UI evaluation methodologies, offering an organized and effective framework for future usability testing endeavors.

关键词： heuristic evaluation usability testing analytic hierarchy process usability algorithm efficiency expert evaluation human-computer interaction user interface

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Framed-Quadtree Path Planning for an Underwater Vehicle with the Task of Tracking a Moving Target

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Journal of Marine Science and Application 2010年第1期9卷 27-33页

作者：高博徐德民严卫生 College of Marine Engineering Northwestern Polytechnical University

An autonomous underwater vehicle (AUV) must use an algorithm to plan its path to distant, mobile offshore objects. Because of the uneven distribution of obstacles in the real world, the efficiency of the algorithm decreases if the global environment is represented by regular grids with all of them at the highest resolution. The framed quadtree data structure is able to more efficiently represent the environment. When planning the path, the dynamic object is expressed instead as several static objects which are used by the path planner to update the path. By taking account of the characteristics of the framed quadtree, objects can be projected on the frame nodes to increase the precision of the path. Analysis and simulations showed the proposed planner could increase efficiency while improving the ability of the AUV to follow an object.

关键词： regular grid framed quadtree data structure algorithm efficiency

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