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LFM Signal Parameters Estimation Using Optimization Approach Initialized by Lipschitz Constant Assisted direct algorithm

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CIRCUITS SYSTEMS AND SIGNAL PROCESSING 2015年第6期34卷 2037-2051页

作者： Ding, Dan Cheng, Naiping Liao, Yurong Acad Equipment Dept Opt & Elect Equipment Beijing Peoples R China

In this paper, the widely used numerical optimization method for estimating linear frequency modulated signal parameters is modified. To this purpose, an improved Dividing RECTangles (direct) algorithm, called the Lipschitz constant assisted direct (L-direct) algorithm, is proposed to substitute for the commonly used Grid Search method. The proposed global optimization algorithm can provide initial estimates for local optimization algorithms such as Newton and Simplex. Based on the classical direct algorithm, the L-direct algorithm eliminates hopeless areas, suspends unlikely areas, and concentrates on promising areas in search space, thus determining the range of attraction for local optimization algorithms with lower SNR thresholds or lessened computational burdens. The effect of the modification is validated by simulation results.

关键词： Linear frequency modulated signal Parameter estimation direct algorithm Global optimization Local optimization

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A direct algorithm for Nonorthogonal Approximate Joint Diagonalization

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IEEE TRANSACTIONS ON SIGNAL PROCESSING 2012年第1期60卷 39-47页

作者： Chabriel, Gilles Barrere, Jean Univ Sud Toulon Var IM2NP CNRS UMR 6242 F-83957 La Garde France

While a pair of N x N matrices can almost always be exactly and simultaneously diagonalized by a generalized eigen-decomposition, no exact solution exists in the case of a set with more than two matrices. This problem, termed approximate joint diagonalization (AJD), is instrumental in blind signal processing. When the set of matrices to be jointly diagonalized includes at least N linearly independent matrices, we propose a suboptimal but closed-form solution for AJD in the direct least-squares sense. The corresponding non-iterative algorithm is given the acronym DIEM (DIagonalization using Equivalent Matrices). Extensive numerical simulations show that DIEM is both fast and accurate compared to the state-of-the-art iterative AJD algorithms.

关键词： Approximate joint diagonalization (AJD) blind source separation (BSS) direct algorithm exact joint diagonalization (EJD) non-iterative algorithm simultaneous diagonalization

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A Multi-Objective direct algorithm Toward Structural Damage Identification With Limited Dynamic Response Information

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JOURNAL OF NONDESTRUCTIVE EVALUATION, DIAGNOSTICS AND PROGNOSTICS OF ENGINEERING SYSTEMS 2018年第2期1卷 021004页

作者： Cao, Pei Shuai, Qi Tang, Jiong Univ Connecticut Dept Mech Engn Storrs CT 06269 USA Chongqing Univ Dept Automot Engn Chongqing 400014 Peoples R China

A major challenge in structural health monitoring (SHM) is to accurately identify both the location and severity of damage using the dynamic response information acquired. While in theory the vibration-based and impedance-based methods may facilitate damage identification with the assistance of a credible baseline finite element model, the response information is generally limited, and the measurements may be heterogeneous, making an inverse analysis using sensitivity matrix difficult. Aiming at fundamental advancement, in this research we cast the damage identification problem into an optimization problem where possible changes of finite element properties due to damage occurrence are treated as unknowns. We employ the multiple damage location assurance criterion (MDLAC), which characterizes the relation between measurements and predictions (under sampled elemental property changes), as the vector-form objective function. We then develop an enhanced, multi-objective version of the dividing rectangles (direct) approach to solve the optimization problem. The underlying idea of the multi-objective direct approach is to branch and bound the unknown parametric space to converge to a set of optimal solutions. A new sampling scheme is established, which significantly increases the efficiency in minimizing the error between measurements and predictions. The enhanced direct algorithm is particularly suited to solving for unknowns that are sparse, as in practical situations structural damage affects only a small region. A number of test cases using vibration response information are executed to demonstrate the effectiveness of the new approach.

关键词： damage identification MDLAC multi-objective optimization direct algorithm

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The Branch-and-Bound algorithm for the Traveling Salesman Problem is Not a direct algorithm

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AUTOMATIC CONTROL AND COMPUTER SCIENCES 2021年第7期55卷 816-826页

作者： Maksimenko, A. N. Demidov Yaroslavl State Univ Yaroslavl 150003 Russia

This article considers the concept of a linear separation direct algorithm introduced by V.A. Bondarenko in 1983. The concept of a direct algorithm is defined using the solution graph of a combinatorial optimization problem. The vertices of this graph are all feasible solutions of the problem. Two solutions are called adjacent if there are input data for which these and only these solutions are optimal. A key feature of direct algorithms is that their complexity is bounded from below by the clique number of the solution graph. In 2015-2018, there were five articles published, the main results of which are estimates of the clique numbers of polyhedron graphs associated with various combinatorial optimization problems. The thesis that the class of direct algorithms is broad and includes many classical combinatorial algorithms, including the branch-and-bound algorithm for the traveling salesman problem proposed by J.D.C. Little, K.G. Murty, D.W. Sweeney, and C. Karel in 1963, was the main motivation for these articles. We show that this algorithm is not a direct algorithm. Earlier, in 2014, the author of this article showed that the Hungarian algorithm for the assignment problem is not a direct algorithm. Therefore, the class of direct algorithms is not as broad as previously assumed.

关键词： branch-and-bound method traveling salesman problem linear decision tree clique number direct algorithm

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Human face detection with neural networks and the direct algorithm

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ARTIFICIAL LIFE AND ROBOTICS 2008年第1-2期12卷 112-115页

作者： Chang, Yau-Zen Hung, Kao-Ting Lee, Shih-Tseng Chang Gung Univ Dept Mech Engn Tao Yuan 33302 Taiwan Chang Gung Mem Hosp Med Augmented Real Res & Dev Ctr Linkou Branch Tao Yuan Taiwan

Based on Rowley's approach, this article proposes a new architecture that uses a specifi c optimization technique, the direct (DIviding RECTangle) algorithm, to improve the effi ciency of face detection in images. The system consists of two main parts: a neural network-based face detection arbitrator, and a search strategy based on an integer-handling direct algorithm. By the architecture, the number of arbitrations is dramatically reduced, and human faces, if they are present in an image, are not restricted to predetermined resolutions and aspect ratios. Experimental results show that the proposed architecture is effi cient in terms of both speed and robustness.

关键词： Face detection Neural network Image processing Image pattern recognition direct algorithm

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Linear scaling and the direct algorithm

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JOURNAL OF GLOBAL OPTIMIZATION 2013年第3期56卷 1233-1245页

作者： Liu, Qunfeng Dongguan Univ Technol Sch Comp Dongguan 523808 Peoples R China

In this paper, we discuss the performance of the direct global optimization algorithm on problems with linear scaling. We show with computations that the performance of direct can be affected by linear scaling of the objective function. We also provide a theoretical result which shows that direct does not perform well when the absolute value of the objective function is large enough. Then we present direct-a, a modification of direct, to eliminate the sensitivity to linear scaling of the objective function. We prove theoretically that linear scaling of the objective function does not affect the performance of direct-a. Similarly, we prove that some modifications of direct are also unaffected by linear scaling of the objective function, while the original direct algorithm is sensitive to linear scaling. Numerical results in this paper show that direct-a is more robust than the original direct algorithm, which support the theoretical results. Numerical results also show that careful choices of the parameter epsilon can help direct perform well when the objective function is poorly linearly scaled.

关键词： direct algorithm Global optimization Linear scaling

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Fuel Efficiency Optimization of Input-Split Hybrid Electric Vehicle using direct algorithm 9

Fuel Efficiency Optimization of Input-Split Hybrid Electric ...

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9th Int Conf Ind Information Syst (ICIIS2014)

作者： Panday, Aishwarya Bansal, Hari Om Birla Inst Technol & Sci Dept Elect & Elect Engn Pilani Rajasthan India

ISBN: (纸本)9781479964994

For cleaner and greener future, Hybrid vehicle has been accepted as best practical applications for transportation. The presence of two power sources, i.e. engine and battery in hybrid electric vehicles makes it necessary to intelligently split the power for lesser fuel consumption. An intelligent power management strategy is developed to fulfil on road power demand with good fuel economy. This article uses direct method to control toggling between the engine and battery to reduce the overall liquid fuel consumption. The battery charge is utilized effectively without deteriorating its health. The control strategy is based on the optimization of vital parameters such as state of charge in the battery, engine idle speed, engine on duration and power demand. Numerous simulations are executed on the advanced vehicle simulator (ADVISOR) to authenticate the feasibility of the proposed controller.

关键词： Hybrid electric vehicle power -split configuration direct algorithm State of charge Fuel economy energy optimization

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Structural Damage Identification with Multi-Objective direct algorithm Using Natural Frequencies and Single Mode Shape

Structural Damage Identification with Multi-Objective DIRECT...

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SPIE Conference on Health Monitoring of Structural and Biological Systems

作者： Cao, Pei Yoo, David Shuai, Qi Tang, J. Univ Connecticut Dept Mech Engn Storrs CT 06269 USA

ISBN: (数字)9781510608269

ISBN: (纸本)9781510608252;9781510608269

Structural damage identification has been continuously pursued in engineering practices to facilitate diagnosis and prognosis in structural health monitoring (SHM) systems. In SHM, the changes of modal parameters are frequently used as inputs. In this research, we employ the multiple damage location assurance criterion (MDLAC) to characterize the correlation between predictions of both frequency changes and single mode shape change with the measured data. The damage locations and severities can be obtained by maximizing the MDLAC values. Thereafter, a multi-objective optimization problem based on their MDLAC values can be formulated and optimized by applying a newly devised multi-objective direct approach. The proposed approach offers practical attractions of only requiring a short amount of computational time, and the results are conclusive and repeatable.

关键词： damage identification SHM MDLAC multi-objective optimization direct algorithm

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Modified direct algorithm for Scaled Global Optimization Problems 3

Modified DIRECT Algorithm for Scaled Global Optimization Pro...

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3rd World Congress of Global Optimization (WCGO)

作者： Liu, Qunfeng Zhang, Jianxiong Chen, Fen Dongguan Univ Technol Dongguan Peoples R China

ISBN: (纸本)9783319083773;9783319083766

direct is a popular deterministic algorithm for global optimization problems. It can find the basins of attraction for global or local optima efficiently, especially when dimension is small. Recently, we have proposed a class of modified direct algorithms to eliminate the sensitivities of the original direct to linear scaling of the objective function. In this paper, we devote to find a specific algorithm with best performance among this class. We compare the performance of the modified direct algorithms on the GKLS test set. Numerical results show that direct-median performs outstanding among this class. What is more, numerical results also show that direct-median can find solutions with high accuracy much more efficiently than the original direct.

关键词： Global optimization direct algorithm Linear scaled objective function

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A Computational Study on Different Penalty Functions with direct algorithm

A Computational Study on Different Penalty Functions with DI...

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13th International Conference on Computational Science and Its Applications (ICCSA)

作者： Rocha, Ana Maria A. C. Vilaca, Rita Univ Minho Sch Engn Dept Prod & Syst P-4710057 Braga Portugal Univ Minho Algoritmi R&D Ctr P-4710057 Braga Portugal

ISBN: (纸本)9783642396373

The most common approach for solving constrained optimization problems is based on penalty functions, where the constrained problem is transformed into an unconstrained problem by penalizing the objective function when constraints are violated. In this paper, we analyze the implementation of penalty functions, within the direct algorithm. In order to assess the applicability and performance of the proposed approaches, some benchmark problems from engineering design optimization are considered.

关键词： Global optimization constrained optimization direct algorithm penalty function.

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