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INPUT selection FOR A 2ND-ORDER MASS PROPERTY ESTIMATOR

JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 1988年第3期11卷 207-212页

作者： RICHFIELD, RF WALKER, BK BERGMANN, EV UNIV CINCINNATI DEPT AERONAUT ENGN & ENGN MECH CINCINNATI OH 45221 USA CHARLES STARK DRAPER LAB INC CAMBRIDGE MA 02139 USA

A strategy is developed for selecting online the attitude control jet firings to be commanded during the mass property estimation phase of the operation of any asymmetrical rigid satellite. Using symbolic manipulation, an effort is made to develop a selection stratgegy that accelerates convergence by maximally decreasing the change in the covariance of the estimation error at each time step. These results, which are too complex for online implementation, motivate a suboptimal direct search stragegy. Examples of mass property identification are then demonstrated on a high-fidelity simulation of the Space Shuttle. The results indicate that the suboptimal strategies yield significant reductions in the time to convergence for the mass property estimates and in the cumulative fuel usage relative to a typical predetermined jet firing sequence. © 1988 American Institute of Aeronautics and Astronautics, Inc., All rights reserved.

关键词： Space Shuttle Attitude Control System Satellites Fuel Consumption selection algorithm Reaction Control System Flight Computer Autopilot Flight Control System Space Shuttle Orbiter

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A routing cooperative selection method based on ant colony optimization algorithm

A routing cooperative selection method based on ant colony o...

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International Conference on Cyberspace Technology (CCT 2014)

作者： Sun Dandan Zhang Hongxin School of Electronic Engineering Beijing University of Posts and Telecommunications 100876 China Sch. of Electron. Eng. Beijing Univ. of Posts & Telecommun. Beijing China

ISBN: (纸本)9781510802704

Cooperative routing selection algorithm is based on the limited bandwidth and collaborative remain energy, according to pheromone concentration in Ant colony optimization algorithm. The ant colony optimization algorithm is applied to improving collaboration network routing problems to reduce network congestion and reduce node energy consumption. Simulation demonstrate that the algorithm obtains a global optimization and makes an average 60% reduction in end to end delay, increased the utilization of network resources.

关键词： Ant colony optimization algorithm Pheromone density The Cooperative routing ant algorithm Ant colony optimization Network routing Web resources Optimization algorithms Network Congestion selection algorithm Global optimization algorithms selection methods node energy

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Winning at the Starting Line: Unreliable Data Replica selection for Edge Data Integrity Verification

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IEEE TRANSACTIONS ON SERVICES COMPUTING 2024年第6期17卷 4481-4493页

作者： Zhao, Yao Qu, Youyang Xiang, Yong Chen, Feifei Uddin, Md Palash Gao, Longxiang Deakin Univ Sch Informat Technol Burwood Vic 3125 Australia Qilu Univ Technol Minist Educ Shandong Acad Sci Shandong Comp Sci CtrKey Lab Comp Power Network & Jinan 250353 Peoples R China Shandong Fundamental Res Ctr Comp Sci Shandong Prov Key Lab Comp Power Internet & Serv C Jinan 250353 Peoples R China

Mobile Edge Computing (MEC) is an emerging technology, where App vendors are allowed to cache multiple data replicas on geographically distributed edge servers to serve adjacent mobile subscribers. However, this benefit introduces an extra workload for edge servers and App vendors, as they must audit the integrity of multiple data replicas periodically considering various threats caused by distributed and dynamic MEC environments. The large-scale growth of data replicas certainly is a challenge to design more efficient Edge Data Integrity (EDI) verification approaches. Existing solutions are mostly limited to improving efficiency by optimizing proof generation and verification methods, while the improvement is still far from satisfactory due to adopting indiscriminate inspection philosophy (checking all data replicas without discrimination). In this paper, we make the first attempt to abstract a pre-processing phase and correspondingly study the Unreliable data Replica selection (URS) problem. It can be seamlessly integrated into existing EDI solutions by solving the URS problem at the start of each verification round. Such pre-selection can significantly enhance overall EDI verification efficiency by incorporating the cache service Quality of Service (QoS) and verification success rate, especially in scenarios with a large number of data replicas. Specifically, we first formalize the URS problem as a constrained optimization problem, and further prove its NP -hardness. To address the problem efficiently, we transform it into an easy-to-handle form and develop a Priority-based approach named URS-P. Both theoretical analysis and experimental evaluation validate the effectiveness and efficiency of our proposed solution.

关键词： Quality of service Servers Distributed databases Inspection Monitoring Data integrity Optimization Real-time systems Accuracy Vehicle safety Edge data integrity optimization selection algorithm submodular function unreliable data replica

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Tractable Goal selection for Embedded Systems with Oversubscribed Resources

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JOURNAL OF AEROSPACE COMPUTING INFORMATION AND COMMUNICATION 2011年第5期8卷 151-169页

作者： Rabideau, Gregg Chien, Steve McLaren, David CALTECH Jet Prop Lab Artificial Intelligence Grp Pasadena CA 91109 USA

We describe an efficient, online goal selection algorithm and its use for selecting goals at runtime. Our focus is on the replanning that must be performed in a timely manner on the embedded system where computational resources are limited (as in many aerospace systems). In particular, our algorithm generates near optimal solutions to problems with fully specified goal requests that can oversubscribe available resources but have no temporal flexibility. By using a fast, incremental algorithm, goal selection can be postponed in a "just-in-time" fashion allowing requests to be changed or added at the last minute. This enables shorter response cycles and greater autonomy for the system under control. We show that the average case complexity for updating the goals set is O(N IgN) and runtime execution isO(N). We perform an empirical analysis on both synthetic data and space operations mission-like scenarios that confirm these performance characteristics. Finally, we show that scaling these performance figures to existing, very limited onboard spacecraft embedded environments (a Mars Reconnaissance Orbiter like environment) appears feasible.

关键词： Embedded Systems selection algorithm Space Operations Aerospace System Mars Exploration Rover Earth Flight Computer Data Storage C++ Programming Language Spitzer Space Telescope

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selection-based capacitor voltage balancing control for modular multilevel converters

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JOURNAL OF POWER ELECTRONICS 2021年第10期21卷 1427-1438页

作者： Luo, Wei Ma, Yifan Zheng, Changbao Univ Shanghai Sci & Technol Dept Elect Engn Shanghai Peoples R China Anhui Univ Collaborat Innovat Ctr Ind Energy Saving & Power Hefei Anhui Peoples R China

The modular multilevel converter (MMC) is a promising topology for high-power converters. The capacitor voltage balancing method for the submodules (SMs) is one of the key technologies in terms of modular multilevel converters. Aiming at the problems of the large calculation burden and the high switching frequency in the traditional capacitor voltage balancing method, an improved balancing method based on a novel selection algorithm for MMCs is proposed in this paper. The proposed method can avoid the sorting operation of the arm SM voltages in each control cycle without reducing the control precision of the capacitor voltages. In addition, it greatly improves the sorting efficiency. Thus, a criterion for algorithm rerun is introduced, which makes the MMC controller avoid reordering the capacitor voltages and leave the control signals unchanged when the capacitor voltages experience small changes. Finally, simulation and experimental results confirm the feasibility and effectiveness of the proposed method.

关键词： Modular multilevel converter (MMC) Capacitor voltage balancing selection algorithm Hardware-in-the-loop simulation

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Study on selection of Test Space for CW Illuminator

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IEICE TRANSACTIONS ON COMMUNICATIONS 2022年第11期E105B卷 1434-1443页

作者： Zhou, Qi Zhou, Zhongyuan Gu, Yixing Sheng, Mingjie Hu, Peng Xiao, Yang Southeast Univ Sch Mech Engn Electromagnet Compatibil Lab Nanjing 211189 Peoples R China

This paper introduces the working principle of continuous wave (CW) illuminator and selects the test space by developing the wave impedance selection algorithm for the CW illuminator. For the vertical polarization and the horizontal polarization of CW illuminator, the law of wave impedance distribution after loading is analyzed and the influence of loading distribution on test space selection is studied. The selection principle of wave impedance based on incident field or total field at the monitoring point is analyzed.

关键词： CW illuminator selection algorithm distribution design test space

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selection from read-only memory with limited workspace

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THEORETICAL COMPUTER SCIENCE 2014年第0期554卷 64-73页

作者： Elmasry, Amr Juhl, Daniel Dahl Katajainen, Jyrki Satti, Srinivasa Rao Univ Alexandria Dept Comp Engn & Syst Alexandria Egypt Univ Copenhagen Dept Comp Sci DK-1168 Copenhagen Denmark Seoul Natl Univ Sch Comp Sci & Engn Seoul 151 South Korea

Given an unordered array of N elements drawn from a totally ordered set and an integer k in the range from 1 to N, in the classic selection problem the task is to find the k-th smallest element in the array. We study the complexity of this problem in the space-restricted random-access model: The input array is stored on read-only memory, and the algorithm has access to a limited amount of workspace. We prove that the linear-time prune-and-search algorithm-presented in most textbooks on algorithms-can be modified to use Theta(N) bits instead of Theta(N) words of extra space. Prior to our work, the best known algorithm by Frederickson could perform the task with Theta(N) bits of extra space in O (Nlg* N) time. Our result separates the space-restricted randomaccess model and the multi-pass streaming model, since we can surpass the Omega(Nlg* N) lower bound known for the latter model. We also generalize our algorithm for the case when the size of the workspace is O (S) bits, where lg(3) N <= S <= N. The running time of our generalized algorithm is O (Nlg* (N/S) + N(lgN)/lg S), slightly improving over the O (Nlg*(N (lgN)/S) + N(lgN)/lg S) bound of Frederickson's algorithm. To obtain the improvements mentioned above, we developed a new data structure, called the wavelet stack, that we use for repeated pruning. We expect the wavelet stack to be a useful tool in other applications as well. (C) 2014 Elsevier B.V. All rights reserved.

关键词： selection algorithm Read-only memory Random-access machine Multi-pass streaming Bit vector Wavelet stack

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selection and Rate-Adaptation Schemes for MIMO Multiple-Access Channels With Low-Rate Channel Feedback

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IEEE TRANSACTIONS ON INFORMATION THEORY 2015年第11期61卷 5948-5975页

作者： Tang, Ti-Wen Tien, Hsiao-Ting Lu, Hsiao-feng (Francis) Natl Chiao Tung Univ Dept Elect & Comp Engn Hsinchu 300 Taiwan Natl Chiao Tung Univ Dept Elect & Comp Engn Hsinchu 30010 Taiwan

In this paper, two selection schemes are proposed for coded transmission over multiple-input multiple-output (MIMO) multiple-access channels (MAC) to yield a much higher diversity-multiplexing gain tradeoff (DMT) performance. These schemes require a channel feedback, but at an extremely low rate. The first scheme is based on user selection and can be easily implemented in the existing MIMO-MAC systems. Upper bounds on the minimal computational complexity required by sphere decoders to decode DMT-optimal codes for this scheme as well as for MIMO MAC without feedback are given. It is shown that this scheme can offer both a much larger DMT and an exponential reduction on decoding complexity, compared with the latter. The second scheme selects jointly the users and their transmit antennas. It requires an additional design of rate assignments for performance optimization. A very general framework on the design of optimal rate assignments is thus provided. It is shown that this scheme can yield DMT performances far superior to the optimal MIMO-MAC DMT without channel feedback. The simulation results confirm that in some cases, this scheme can provide an astonishing SNR gain of 14.64 dB at outage probability 10(-6) compared with the optimal MIMO-MAC coding schemes without feedback.

关键词： MIMO multiple-access channel feedback channel diversity-multiplexing tradeoff selection algorithm rate adaptation

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Feature selection, Clustering, and Prototype Placement for Turbulence Datasets

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AIAA JOURNAL 2022年第3期60卷 1332-1346页

作者： Barone, Matthew Ray, Jaideep Domino, Stefan Sandia Natl Labs Aerosci Dept Tech Staff Albuquerque NM 87185 USA Sandia Natl Labs Extreme Scale Data Sci & Analyt Dept Tech Staff Albuquerque NM 87185 USA Sandia Natl Labs Computat Thermal & Fluid Mech Dept Tech Staff Albuquerque NM 87185 USA Stanford Univ Inst Computat & Math Engn Stanford CA 94305 USA

This paper explores automated approaches for the analysis and categorization of turbulent flow data as a means of assessing the quality of a turbulence dataset used for constructing data-driven turbulence closures. Single-point statistics from several high-fidelity turbulent flow simulation datasets are differentiated into groups using a Gaussian mixture model clustering algorithm. Candidate features are proposed, and a feature selection algorithm is applied to the data in a sequential fashion, flow by flow, to identify a good feature set and an optimal number of clusters for each dataset. Clusters are first identified for plane channel flows, producing results that agree with existing theory and empirical observations. Further clusters are then identified in an incremental fashion for flow over a wavy-walled channel, flow over a bump in a channel, and flow past a square cylinder. Some clusters are closely identified with the anisotropy state of the turbulence, whereas others can be connected to physical phenomena, such as boundary-layer separation and free shear layers. Exemplar points from the clusters, or prototypes, are then identified using a prototype placement method. These exemplars effectively summarize the dataset using a greatly reduced collection of data points. The clusters and their prototypes are used to assess the quality of a training dataset constructed by simply pooling the four flows. We enumerate the dataset's shortcomings and state the limits of generalizability of any data-driven closure trained on it.

关键词： Turbulence Kinetic Energy Turbulent Flow Boundary Layer Separation Gaussian Mixture Models selection algorithm Computational Fluid Dynamics Reynolds Averaged Navier Stokes Turbulence Models Velocity Profiles Principal Stresses

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Rough Terrain Mapping and Classification for Foothold selection in a Walking Robot

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JOURNAL OF FIELD ROBOTICS 2011年第4期28卷 497-528页

作者： Belter, Dominik Skrzypczynski, Piotr Poznan Univ Tech Inst Control & Informat Engn Ul Piotrowo 3A PL-60965 Poznan Poland

Although legged locomotion over a moderately rugged terrain can be accomplished by employing simple reactions to the ground contact information, a more effective approach, which allows predictively avoiding obstacles, requires a model of the environment and a control algorithm that takes this model into account when planning footsteps and leg movements. This article addresses the issues of terrain perception and modeling and foothold selection in a walking robot. An integrated system is presented that allows a legged robot to traverse previously unseen, uneven terrain using only onboard perception, provided that a reasonable general path is known. An efficient method for real-time building of a local elevation map from sparse two-dimensional (2D) range measurements of a miniature 2D laser scanner is described. The terrain mapping module supports a foothold selection algorithm, which employs unsupervised learning to create an adaptive decision surface. The robot can learn from realistic simulations;therefore no a priori expert-given rules or parameters are used. The usefulness of our approach is demonstrated in experiments with the six-legged robot Messor. We discuss the lessons learned in field tests and the modifications to our system that turned out to be essential for successful operation under real-world conditions. (C) 2011 Wiley Periodicals, Inc.

关键词： field experimentation walking robots Legged robot Biped locomotion Unsupervised learning Contact Information selection algorithm terrain mapping terrains Rough terrain Computer algorithms

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