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Optimization of a tetrahedral satellite formation

JOURNAL OF SPACECRAFT AND ROCKETS 2005年第4期42卷 699-710页

作者： Clemente, DC Atkins, EM Univ Maryland College Pk MD 20742 USA

Two fundamental approaches can be applied to satellite-formation mission design: active control, where satellites exert forces with their thrusters to maintain a constant or periodic geometry for all or part of each orbit, and natural, where satellite orbits are designed to naturally assemble a geometry for all or part of each orbit to within a tolerance defined from scientific requirements. An actively controlled formation can be labeled virtual rigid body (VRB) because geometry is precisely maintained as if the satellites were rigidly connected. This work describes a hierarchical optimization method for minimizing mission design computational complexity and applies this method to the design of VRB, natural-orbit, and multi-impulse solutions for a tetrahedron formation applicable to the proposed magnetospheric multiscale mission. Cost is defined in terms of total fuel per second of observation and tetrahedron geometric quality factor. Although both natural-orbit and active solutions are feasible, the active solutions substantially increase average data quality and observation time per orbit at minimum fuel cost, and the multi-impulse solution does not require thruster use during data collection periods.

关键词： Satellite Formation Orbital Period Active Control Orbital Elements Magnetospheric Multiscale Mission Propellant Earth Optimization Algorithm Formation Flying mixed integer linear programming

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Nonlinear control allocation using piecewise linear functions: A linear programming approach

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2005年第3期28卷 558-562页

作者： Bolender, MA Doman, DB USAF Control Design & Anal Branch Wright Patterson AFB OH 45433 USA

The piecewise linear control allocation problem that use a linear programming approach was solved for implementing in a digital flight-control system. It was found that the nonlinear optimization problem can be cast as a linear programming problem where a subset of the decision variables are subject to restricted basis entry rules. It was shown that a simplex algorithm that enforces the restricted basis entry rules can be solved fast enough for use in a real-time flight-control system. The early termination of the simplex algorithm must be addressed to ensure that when a feasible solution to the control allocation problem exists, it is always found.

关键词： linear programming Nonlinear Control mixed integer linear programming Digital Flight Control System Control Surfaces Digital Flight Control Computer Branch and Bound Algorithm Closed Loop Aerodynamic Interference linear Interpolation

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Penalty-function guidance for multiple-satellite cluster formation

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2005年第1期28卷 182-185页

作者： Umehara, H McInnes, CR Univ Glasgow Glasgow G12 8QQ Lanark Scotland Kashima Space Res Ctr Natl Inst Informat & Commun Technol Space Cybernet Grp Kashima 3148501 Japan Univ Strathclyde Dept Engn Mech Glasgow G1 1XJ Lanark Scotland

A fuel-minimization and near-miss avoidance control are developed for clustered satellites. A penalty function of class C2 with respect to the distances between satellites is imposed on the fuel-consumption index. It ... 详细信息

A fuel-minimization and near-miss avoidance control are developed for clustered satellites. A penalty function of class C² with respect to the distances between satellites is imposed on the fuel-consumption index. It is found enough to solve just the two-point boundary-value problem even if unspecified multiple near misses occur between satellites. The proposed simulation procedure is to repeat shooting searches and to increase the height of the penalty function.

关键词： Low Earth Orbit Satellites Fuel Consumption Boundary Value Problems Newton Raphson Method mixed integer linear programming Runge Kutta Integration Numerical Simulation Iterative Algorithm Telecommunication Orbital Elements

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Optimum integrated link scheduling and power control for ad hoc wireless networks

Optimum integrated link scheduling and power control for ad ...

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IEEE International Conference on Wireless and Mobile Computing, Networking And Communications (WiMob)

作者： A. Behzad I. Rubin P. Chakravarty Electrical Engineering Department University of California Los Angeles CA USA

In this paper, we develop a new mathematical programming formulation for minimizing the schedule length in ad hoc wireless networks based on the optimal joint scheduling of transmissions across the multi-access communication links and allocation of transmit power levels, while meeting the requirements on the signal-to-interference and noise ratio (SINR) at intended receivers. We prove that the problem can be represented as a mixed integer linear programming (MILP) and show that the latter yields a solution that consists of transmit power levels that are strongly Pareto optimal. We demonstrate that our MILP formulation can be used effectively to derive optimal scheduling and power levels for networks with as many as 30 designated communication links. We exhibit that the MILP formulation can be also effectively solved to provide tight upper and lower bounds (corresponding to an approximation factor /spl Delta/) for the optimum schedule length of networks with as many as 100 designated links. We prove that the integrated link scheduling and power control problem is NP-complete. Consequently, we develop and investigate a heuristic algorithm of polynomial complexity (O|LO|/sup 5/) for solving the problem in a timely and practical manner. Our algorithm is based on the properties of a novel interference graph (the power-based interference graph) that we have introduced. We demonstrate that the frame length of schedules realized by our heuristic schemes reside in the 25 percentile of those attained by the optimal mechanism for randomly generated topologies.

关键词： Power control Wireless networks Optimal scheduling Signal to noise ratio Interference Mathematical programming Noise level mixed integer linear programming Heuristic algorithms Polynomials

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Power controlled minimum frame length scheduling in TDMA wireless networks with sectored antennas

Power controlled minimum frame length scheduling in TDMA wir...

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IEEE Annual Joint Conference: INFOCOM, IEEE Computer and Communications Societies

作者： A.K. Das R.J. Marks P. Arabshahi A. Gray Department of Electrical Engineering University of Washington Seattle WA USA School of Engineering and Computer Science Baylor University Waco TX USA Jet Propulsion Laboratory Pasadena CA USA

We consider the problem of power controlled minimum frame length scheduling for TDMA wireless networks. Given a set of one-hop transmission requests, our objective is to schedule them in a minimum number of time slots, so that each slot schedule is free of self-interferences and meets desired SINR constraints. Additionally, the transmit power vector corresponding to each slot schedule should be minimal. We consider two different versions of the problem, a per-slot version and a per-frame version, and develop mixed integer linear programming models which can be used for solving the problems optimally. In addition, we propose a heuristic algorithm for the per-slot version.

关键词： Intelligent networks Time division multiple access Wireless networks Power control Signal to noise ratio Scheduling algorithm mixed integer linear programming Heuristic algorithms Ad hoc networks Slot antennas

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Improving energy efficiency for multicasting in wireless ad-hoc networks with adaptive antennas

Improving energy efficiency for multicasting in wireless ad-...

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IEEE International Conference on Wireless and Mobile Computing, Networking And Communications (WiMob)

作者： Song Guo O. Yang School of Information Technology and Engineering University of Ottawa Ottawa ONT Canada

We consider the performance of various algorithms to maximize the lifetime of a given multicast connection in wireless networks that use directional antennas and have limited energy resources. Based on the IMILP (mixed integer linear programming) formulation [S. Guo et al, 2005], which provides a globally optimal solution to this problem for a small or medium network, we can evaluate the realistic performance of different heuristic algorithms. Experimental results show that minimum total power consumption does not guarantee maximum lifetime for either broadcasting or multicasting, and the algorithms S-DPMT and D-DPMT [S. Guo et al, 2004] outperform other energy-aware multicast algorithms significantly in terms of multicast lifetime.

关键词： Energy efficiency Ad hoc networks Adaptive systems Adaptive arrays Multicast algorithms Wireless networks Directional antennas Energy resources mixed integer linear programming Heuristic algorithms

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Multi-factory optimization enables kit reconfiguration in semiconductor manufacturing

Multi-factory optimization enables kit reconfiguration in se...

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IEEE International Conference on Automation Science and Engineering (CASE)

作者： M.T. Zhang S. Niu M. Mai Qi Li Intel Shanghai Operations Research and Solutions Shanghai China Operations Research & Solutions Intel Pudong Shangai Shanghai China Information Service and Technology Group Intel Corporation Shanghai China Flash Manufacturing Systems Intel Pudong Shangai Shanghai China

To enable the huge saving of the kit-breakdown, we developed MaxIt v1.2 to generate an optimal capacity plan at the kit component level for the mid-range build plan in multi-factory environment. We describe the MILP (mixed integer linear programming) model and system architecture of MaxIt v1.2. We also conduct detailed sensitivity analysis on parameter setting and objective prioritizing. With the implementation in the Intel Shanghai and Manila sites, we have significantly improved data integrity and enabled a -US/spl ges/ cost savings.

关键词： Semiconductor device manufacture Testing Capacity planning mixed integer linear programming Assembly Costs Business process re-engineering Production Operations research Manufacturing systems

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Predictive energy management strategies for hybrid vehicles

Predictive energy management strategies for hybrid vehicles

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IEEE Conference on Vehicle Power and Propulsion (VPPC)

作者： Mutasim Salman Man-Feng Chang Jyh-Shin Chen Electrical and Controls Integration Lab. Of GM Research and Development Center

In this paper, predictive energy management strategies that utilize the previewed traffic pattern and terrain information are developed. A generalized predictive optimal control framework is used to find the conditions under which the predictive strategies, will give superior fuel economy to that of the instantaneous strategies. mixed integer linear programming methodology, with no assumptions on the control structure, is used to find the predictive energy management strategies. It is shown, by using theoretical work and simulation, that certain conditions are needed to make the predictive strategies, that utilize the previewed driving pattern and terrain information, give superior fuel economy to the instantaneous ones.

关键词： Energy management Fuel economy Vehicle driving Optimal control Vehicle dynamics Predictive models mixed integer linear programming Internal combustion engines Wheels Electric motors

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An algebraic decision diagram (ADD) based technique to find leakage histograms of combinational designs

An algebraic decision diagram (ADD) based technique to find ...

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International Symposium on Low Power Electronics and Design (ISLPED)

作者： K. Gulati N. Jayakumar S.P. Khatri Department of Electrical Engineering Texas A and M University College Station TX USA

In this paper, we present an algebraic decision diagram (ADD) based approach to determine and implicitly represent the leakage value for all input vectors of a combinational circuit. In its exact form, our technique can compute the leakage value of each input vector. To broaden the applicability of our technique, we present an approximate version of our algorithm as well. The approximation is done by limiting the total number of discriminant nodes in any ADD. Previous sleep vector computation techniques can find either the maximum or minimum sleep vector. Our technique computes the leakages for all vectors, storing them implicitly in an ADD structure. We experimentally demonstrate that these approximate techniques produce results which have reasonable errors. We also show that limiting the number of discriminants to a value between 12 and 16 is practical, allowing for good accuracy and lowered memory utilization.

关键词： Histograms Circuits Sleep Permission Very large scale integration Binary decision diagrams Leakage current Vectors mixed integer linear programming

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An enhanced exact procedure for the CMST problem

An enhanced exact procedure for the CMST problem

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International Conference on Information Technology and Applications, ICITA

作者： Jinpeng Huai Jun Han School of Computer Science Beihang University China

ISBN: (纸本)0769523161

This paper studies the capacitated minimum spanning tree problem, which is one of the most fundamental and significant problems in the optimal design of communication networks. A solution method using combined neighborhood search and branch and bound technique is introduced and its performance is presented. The advantage of the algorithm is shown while the process of searching for the optimal solution is illustrated. Computational experiences demonstrate that the proposed strategy significantly improves the efficiency of the previous arc-orientated branch and bound algorithm.

关键词： Costs Tree graphs Computer science Communication networks Graph theory mixed integer linear programming Vehicles Routing Computer errors Information technology

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