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ENERGY MANAGEMENT OF 3-DIMENSIONAL MINIMUM-TIME INTERCEPT

JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 1987年第6期10卷 574-580页

作者： VISSER, HG KELLEY, HJ CLIFF, EM VIRGINIA POLYTECH INST & STATE UNIV DEPT AEROSP & OCEAN ENGNBLACKSBURGVA 24061

A real-time computer algorithm to control and optimize aircraft flight profiles is described and applied to a three-dimensional minimum-time intercept mission. The proposed scheme has roots in two well-known techniques: singular perturbations and neighboring-optimal guidance. Use of singular-perturbation ideas is made in terms of the assumed trajectory-family structure. A heading/energy family of prestored point-mass-model state- Euler solutions is used as the baseline in this scheme. The next step is to generate a near-optimal guidance law that will transfer the aircraft to the vicinity of this reference family. The control commands fed to the autopilot (bank angle and load factor) consist of the reference controls plus correction terms that are linear combinations of the altitude and path-angle deviations from reference values, weighted by a set of precalculated gains. In this respect, the proposed scheme resembles neighboring-optimal guidance. However, in contrast to the neighboringoptimal guidance scheme, the reference control and state variables as well as the feedback gains are stored as functions of energy and heading in the present approach. Some numerical results comparing open-loop optimal and approximate feedback solutions are presented. © 1987 American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

关键词： Energy Management Singular Perturbation Closed Loop Guidance Laws Induced Drag computer algorithm Flight Profile Autopilot Feedback Control Flight Path Angle

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Locally optimal routes for route choice sets

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TRANSPORTATION RESEARCH PART B-METHODOLOGICAL 2020年 141卷 240-266页

作者： Fischer, Samuel M. Univ Alberta Dept Math & Stat Sci Edmonton AB T6G 2G1 Canada

Route choice is often modelled as a two-step procedure in which travellers choose their routes from small sets of promising candidates. Many methods developed to identify such choice sets rely on assumptions about the mechanisms behind the route choice and require corresponding data sets. Furthermore, existing approaches often involve considerable complexity or perform many repeated shortest path queries. This makes it difficult to apply these methods in comprehensive models with numerous origin-destination pairs. In this paper, we address these issues by developing an algorithm that efficiently identifies locally optimal routes. Such paths arise from travellers acting rationally on local scales, whereas unknown factors may affect the routes on larger scales. Though methods identifying locally optimal routes are available already, these algorithms rely on approximations and return only few, heuristically chosen paths for specific origin-destination pairs. This conflicts with the demands of route choice models, where an exhaustive search for many origins and destinations would be necessary. We therefore extend existing algorithms to return (almost) all admissible paths between a large number of origin-destination pairs. We test our algorithm and its applicability in route choice models on the road network of the Canadian province British Columbia and empirical data collected in this province. (C) 2020 Elsevier Ltd. All rights reserved.

关键词： Alternative paths Choice set computer algorithm Local optimality Road network Route choice

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Approximate upper bounds for the critical probability of oriented percolation in two dimensions based on rapidly mixing Markov chains

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JOURNAL OF APPLIED PROBABILITY 1997年第4期34卷 859-867页

作者： Bollabas, B Stacey, A Univ Cambridge Dept Pure Math & Math Stat Cambridge CB2 1SB England

We develop a technique for establishing statistical tests with precise confidence levels for upper bounds on the critical probability in oriented percolation. We use it to give p(c) < 0.647 with a 99.999967% confid... 详细信息

关键词： percolation rapid mixing coupling computer algorithm

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Graph-Theory-Based Derivation, Modeling, and Control of Power Converter Systems

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IEEE JOURNAL OF EMERGING AND SELECTED TOPICS IN POWER ELECTRONICS 2022年第6期10卷 6557-6571页

作者： Li, Yuzhuo Kuprat, Johannes Li, Yunwei Liserre, Marco Univ Alberta Dept Elect & Comp Engn Edmonton AB T6G 2V4 Canada Univ Kiel Chair Power Elect Kiel Germany

Graph-theoretical approaches have been widely applied in many disciplines, however, their implementation in power electronics converters and systems is still in the exploring stage. In this overview, we summarize the milestones and general applications of this powerful mathematical tool and illustrate its unique benefits in some emerging/challenging power electronics research topics, for example, systematic converter derivation and modeling, advanced control, and so on. Given the multidiscipline nature of power electronics, graph theory can serve as a bridge for experts in different disciplines with a universal framework for complex problems. With solid mathematical foundations, it can stimulate research of topological aspects in both converter and systematic levels, fits well for nowadays power electronics converter. It is hoped that this article can serve as a timely and handy summary for engineers/students who want to enter the field and promote the innovation of power-electronics-enabled applications.

关键词： Circuit theory computer algorithm converter modeling and control converter system converter topology duality graph theory isomorphism power routing

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Numeric and mesh algorithms for the Coxeter spectral study of positive edge-bipartite graphs and their isotropy groups

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JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS 2014年第PART B期259卷 815-827页

作者： Bocian, Rafal Felisiak, Mariusz Simson, Daniel Nicolaus Copernicus Univ Fac Math & Comp Sci PL-87100 Torun Poland

We develop algorithmic techniques for the Coxeter spectral analysis of the class UBigr(n) of connected loop-free positive edge-bipartite graphs Delta with n >= 2 vertices (i.e., signed graphs). In particular, we present numerical and graphical algorithms allowing us a computer search in the study of such graphs Delta by means of their Gram matrix G(Delta), the (complex) spectrum specc(Delta) subset of C of the Coxeter matrix Cox(Delta) := -G(Delta) . G(Delta)(-tr) and the geometry of Weyl orbits in the set Mor(D Delta) of matrix morsifications A is an element of M-n(Z) of a simply laced Dynkin diagram D Delta is an element of {A(n), D-n, E-6, E-7, E-8} associated with Delta and mesh root systems of type D Delta. Our algorithms construct the Coxeter-Gram polynomials cox(Delta)(t) is an element of 7 vertical bar t vertical bar and mesh geometries of root orbits of small connected loop-free positive edge-bipartite graphs Delta. We apply them to the study of the following Coxeter spectral analysis problem: Does the Z-congruence Delta approximate to(Z) Delta' hold (i.e., the matrices G(Delta), and G(Delta'), are Z-congruent), for any pair of connected positive loop-free edge-bipartite graphs Delta, Delta' in UBigr(n), such that specc(Delta) = specc(Delta')? The problem if any square integer matrix A is an element of M-n(Z) is Z-congruent with its transpose A(tr) is also discussed. We present a solution for graphs in UBigr(n), with n <= 6. (C) 2013 Elsevier B.V. All rights reserved.

关键词： Edge-bipartite graph Matrix morsification Dynkin diagram Coxeter polynomial Mesh geometry of roots computer algorithm

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Feasibility Analysis of the Scheme of Internet of Things Based on Two-Level Supply Chain Dynamics

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WIRELESS PERSONAL COMMUNICATIONS 2018年第2期103卷 1263-1272页

作者： Luo, Ming Zhou, Guohua Southwest Jiaotong Univ Sch Econ & Management Chengdu 610031 Sichuan Peoples R China

At this stage, due to the continuous development of computer technology, whether in the online shopping or a variety of commercial exchanges with a use of the network, Internet of things is one of the most important operating intermediaries. But as people become more and more enthusiastic about online shopping, it is more and more difficult for the traditional Internet of things to meet the needs. In this paper, a scheme of Internet of things based on two-level supply chain dynamics was established to deal with these problems. In this paper, a rigorous computer algorithm was used to make analysis and summarizing, so that a new Internet of things based on two-level supply chain dynamics was established. Through our tests, the algorithm calculates the data correctly, which can meet the requirements on use.

关键词： computer algorithm Two-level supply chain dynamics A scheme of Internet of things

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MINIMIZATION OF VIBRATION IN ELASTIC BEAMS WITH TIME-VARIANT BOUNDARY-CONDITIONS

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 1992年第5期15卷 1265-1271页

作者： AMIROUCHE, FML XIE, MJ University of Illinois at Chicago Chicago Illinois 60680

This paper presents an innovative method for minimizing the vibration of structures with time-variant boundary conditions (supports). The elastic body is modeled in two ways: 1) the first model is a letter seven type beam with a movable mass not to exceed the lower tip;2) the second model has an arm that is a hollow beam with an inside mass with adjustable position. The complete solutions to both problems are carried out where the body is undergoing large rotation. The quasistatic procedure is used for the time-variant boundary conditions. The method developed employs partial differential equations governing the motion of the beam, including the effects of rigid-body motion, time-variant boundary conditions, and calculus of variations. The analytical solution is developed using Laplace and Fourier transforms. Examples of elastic robotic arms are given to illustrate the effectiveness of the methods developed.

关键词： Robotic Manipulators computer algorithm Space Structures Young's Modulus D'Alembert's Principle Mathematical Models Numerical Simulation Transverse Vibrations Aerospace Engineering Elastic Deformation

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Dynamic Programming Problem for Fractional Discrete-Time Dynamic Systems. Quadratic Index of Performance Case

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CIRCUITS SYSTEMS AND SIGNAL PROCESSING 2014年第7期33卷 2131-2149页

作者： Czyronis, Przemyslaw M. PHO Bumar Elekt PL-04051 Warsaw Poland

Dynamic programming problem for discrete-time fractional order systems with quadratic performance index has been formulated and solved. A new method for numerical computation of optimal dynamic programming problem has been presented. The efficiency of the method has been demonstrated on numerical example and illustrated by graphs. Graphs also show the differences between the fractional and classical (standard) systems theory. Results for other cases of the coefficient , and not illustrated with numerical examples, have been obtained through a computer algorithm written for this purpose.

关键词： Optimal control Dynamic programming Fractional order Discrete-time systems computer algorithm Numerical computation

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A new method of measuring strong currents by their magnetic field

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computerS & ELECTRICAL ENGINEERING 1997年第2期23卷 121-128页

作者： Kreinovich, V Pierluissi, JH Koshelev, M UNIV TEXAS DEPT ELECT & COMP ENGNEL PASOTX 79968

In many situations, it is difficult to measure strong currents directly, so the currents are measured by their magnetic fields (e.g. by sensors glued onto the cable surface). If we have only one cable, then it is easy to reconstruct the current from the magnetic field. But in many real-life situations, there is a neighboring cable whose current is also unknown. Moreover, the cables are hanging freely, so their distance is not precisely known. We show that in such situations, it is sufficient to have two pairs of sensors that measure magnetic field;the unknown current can be uniquely reconstructed from the corresponding measurement results by applying a simple computer algorithm. (C) 1997 Elsevier Science Ltd.

关键词： magnetic field strong current measurements aluminum production computer algorithm

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Generation of Kekule Valence Structures and the Corresponding Valence Bond Wave Function

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JOURNAL OF COMPUTATIONAL CHEMISTRY 2011年第4期32卷 696-708页

作者： Rashid, Zahid Van Lenthe, Joop H. Univ Utrecht Debye Inst Nanomat Sci Theoret Chem Grp Dept Chem NL-3584 CH Utrecht Netherlands

A new scheme, called "list of nonredundant bonds", is presented to record the number of bonds and their positions for the atoms involved in Kekule valence structures of (poly)cyclic conjugated systems. Based on this scheme, a recursive algorithm for generating Kekule valence structures has been developed and implemented. The method is general and applicable for all kinds of (poly)cyclic conjugated systems including fullerenes. The application of the algorithm in generating Valence Bond (VB) wave functions, in terms of Kekule valence structures, is discussed and illustrated in actual VB calculations. Two types of VBSCF calculations, one involving Kekule valence structures only and the second one involving all covalent VB structures, were performed for benzene, pentalene, benzocyclobutadiene, and naphthalene. Both strictly local and delocalised p-orbitals were used in these calculations. Our results show that, when the orbitals are restricted to their own atoms, other VB structures (Dewar structures) also have a significant contribution in the VB wave function. When removing this restriction, the other VB structures (Dewar and also the ionic structures) are accommodated in the Kekule valence structures, automatically. Therefore, at VBSCF delocal level, the ground states of these systems can be described almost quantitatively by considering Kekule valence structures only at a considerable saving of time. (C) 2010 Wiley Periodicals, Inc. J Comput Chem 32: 696-708, 2011

关键词： Kekule valence structures generation of Kekule valence structures computer algorithm valence Bond Method (poly)cyclic conjugated systems

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