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Estimating optimal shoulder immobilization postures following surgical repair of massive rotator cuff tears

JOURNAL OF BIOMECHANICS 2013年第1期46卷 179-182页

作者： Jackson, M. Sylvestre, E. Bleau, J. Allard, P. Begon, M. Univ Montreal Dept Kinesiol Lab Simulat & Modelisat Mouvement Montreal PQ H3C 3J7 Canada Lab Orthoped Medicus Montreal PQ Canada

Although shoulder immobilization is commonly prescribed following surgical repair of rotator cuff tears there is no consensus about the best shoulder immobilization postures. A musculoskeletal model was used with a minimax algorithm to estimate optimal post-operative shoulder immobilization postures for massive rotator cuff tears involving the supraspinatus and infraspinatus. An optimal posture was defined as one in which the stresses in the repaired tendons and the angle of humerus elevation were minimized. The optimal post-operative shoulder immobilization postures were with the humerus elevated and externally rotated. Elevation increased with the severity of the tear from 21 to 45 while external rotation decreased slightly from 23 degrees to 18 degrees. The minimax algorithm effectively balanced the competing criteria, resulting in feasible postures that did not overstress the repaired tendons. This method could be used to guide prescription of shoulder immobilization postures for various injuries. (C) 2012 Elsevier Ltd. All rights reserved.

关键词： Musculoskeletal model Rotator cuff Passive tension Shoulder minimax algorithm

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On minimaxity of Follow the Leader strategy in the stochastic setting

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THEORETICAL COMPUTER SCIENCE 2018年 742卷 50-65页

作者： Kotlowski, Wojciech Poznan Univ Tech Inst Comp Sci Piotrowo 2 PL-60965 Poznan Poland

We consider the setting of prediction with expert advice with an additional assumption that each expert generates its losses i.i.d. according to some distribution. We first identify a class of "admissible" strategies, which we call permutation invariant, and show that every strategy outside this class will perform not better than some permutation invariant strategy. We then show that when the losses are binary, a simple Follow the Leader (FL) algorithm is the minimax strategy for this game, where minimaxity is simultaneously achieved for the expected regret, the pseudo-regret, and the excess risk. Furthermore, FL has also the smallest regret, pseudo-regret, and excess risk over all permutation invariant prediction strategies, simultaneously for all distributions over binary losses. We generalize these minimax results to the case in which each expert generates its losses from a distribution belonging to a one-dimensional exponential family, as well as to the case of loss vectors generated jointly from a multinomial distribution. We also show that when the losses are in the interval [0, 1] and the learner competes against all distributions over [0, 1], FL remains minimax only when an additional trick called "loss binarization" is applied. (C) 2017 Published by Elsevier B.V.

关键词： Online learning Prediction with expert advice Follow the Leader Risk Regret Pseudo-regret Stochastic data minimax algorithm Exponential families

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A geometric theory of form, profile, and orientation tolerances

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PRECISION ENGINEERING-JOURNAL OF THE INTERNATIONAL SOCIETIES FOR PRECISION ENGINEERING AND NANOTECHNOLOGY 1999年第2期23卷 79-93页

作者： Gou, JB Chu, YX Li, ZX Hong Kong Univ Sci & Technol Dept Elect & Elect Engn Clearwater Bay Hong Kong Peoples R China

This article develops a geometric theory which unifies the formulation and computation of form (straightness, flatness, cylindricity, and circularity), profile and orientation tolerances stipulated in ANSI Y14.5M standard. The theory rests on an important observation that a toleranced feature exhibits a symmetry subgroup G(o) under the action of the Euclidean group, SE(3). Thus, the configuration space of a toleranced (or a symmetric) feature can be identified with the homogeneous space SE(3)/G(o) of the Euclidean group. Geometric properties of SE(3)/G(o), especially its exponential coordinates carried over from that of SE(3), are analyzed. We show that all cases of form, profile and orientation tolerances can be formulated as a minimization or constrained minimization problem on the space SE(3)/G(o), with G(o) being the symmetry subgroup of the underlying feature. We develop a simple geometric algorithm, called the Symmetric Minimum Zone (SMZ) algorithm, to unify the computation of form, profile, and orientation tolerances. Finally, we use numerical simulation results comparing the performances of the SMZ algorithm against the best known algorithms in the literature. (C) 1999 Elsevier Science Inc. All rights reserved.

关键词： form tolerance symmetry subgroups homogeneous spaces symmetric localization minimax algorithm tolerance verification

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minimax methods for finding multiple saddle critical points in Banach spaces and their applications

Minimax methods for finding multiple saddle critical points ...

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作者： Yao, Xudong Texas A&M University

This dissertation was to study computational theory and methods for ?nding multiple saddle critical points in Banach spaces. Two local minimax methods were developed for this purpose. One was for unconstrained cases and the other was for constrained cases. First, two local minmax characterization of saddle critical points in Banach spaces were established. Based on these two local minmax characterizations, two local minimax algorithms were designed. Their ?ow charts were presented. Then convergence analysis of the algorithms were carried out. Under certain assumptions, a subsequence convergence and a point-to-set convergence were obtained. Furthermore, a relation between the convergence rates of the functional value sequence and corresponding gradient sequence was derived. Techniques to implement the algorithms were discussed. In numerical experiments, those techniques have been successfully implemented to solve for multiple solutions of several quasilinear elliptic boundary value problems and multiple eigenpairs of the well known nonlinear p-Laplacian operator. Numerical solutions were presented by their pro?les for visualization. Several interesting phenomena of the solutions of quasilinear elliptic boundary value problems and the eigenpairs of the p-Laplacian operator have been observed and are open for further investigation. As a generalization of the above results, nonsmooth critical points were considered for locally Lipschitz continuous functionals. A local minmax characterization of nonsmooth saddle critical points was also established. To establish its version in Banach spaces, a new notion, pseudo-generalized-gradient has to be introduced. Based on the characterization, a local minimax algorithm for ?nding multiple nonsmooth saddle critical points was proposed for further study.

关键词： Multiple Saddle Critical Points Multiple Eigenpairs Multiple Nonsmooth Saddle Critical Points Minmax Characterization minimax algorithm Quasilinear Elliptic PDE p-Laplacian Operator Banach Space Book Thesis

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Consolidation of a WSN and minimax Method to Rapidly Neutralise Intruders in Strategic Installations

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SENSORS 2012年第3期12卷 3281-3301页

作者： Conesa-Munoz, Jesus Ribeiro, Angela UPM CSIC Ctr Automat & Robot Madrid 28500 Spain

Due to the sensitive international situation caused by still-recent terrorist attacks, there is a common need to protect the safety of large spaces such as government buildings, airports and power stations. To address this problem, developments in several research fields, such as video and cognitive audio, decision support systems, human interface, computer architecture, communications networks and communications security, should be integrated with the goal of achieving advanced security systems capable of checking all of the specified requirements and spanning the gap that presently exists in the current market. This paper describes the implementation of a decision system for crisis management in infrastructural building security. Specifically, it describes the implementation of a decision system in the management of building intrusions. The positions of the unidentified persons are reported with the help of a Wireless Sensor Network (WSN). The goal is to achieve an intelligent system capable of making the best decision in real time in order to quickly neutralise one or more intruders who threaten strategic installations. It is assumed that the intruders' behaviour is inferred through sequences of sensors' activations and their fusion. This article presents a general approach to selecting the optimum operation from the available neutralisation strategies based on a minimax algorithm. The distances among different scenario elements will be used to measure the risk of the scene, so a path planning technique will be integrated in order to attain a good performance. Different actions to be executed over the elements of the scene such as moving a guard, blocking a door or turning on an alarm will be used to neutralise the crisis. This set of actions executed to stop the crisis is known as the neutralisation strategy. Finally, the system has been tested in simulations of real situations, and the results have been evaluated according to the final state of the intruders. I

关键词： intelligent systems wireless sensor network decision support systems minimax algorithm path planning risk measure surveillance system

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Research on Techniques of Computer Game

Research on Techniques of Computer Game

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第25届中国控制与决策会议

作者： Hongkun Qiu Fuxiang Gao Yajie Wang Yan Ge Quan Qiu Huimin Sun Engineering Training Center Shenyang Aerospace University Institute of Information Science and Engineering Northeastern University School of Information Science and Engineering Shenyang ligong University

ISBN: (纸本)9781467355339

Computer game is regarded as a new research field of Artificial Intelligence. It's very difficult to design and implement a high-level computer game system. Some techniques of computer game were presented with an example from a chess game-Connect-six. Firstly, introduced the game tree and searching techniques. Secondly, the key technologies for computer games were discussed, including establishment and application of Hash Table, improvement the efficiency of pruning. Finally, some contrasting experiments were performed to test the performance of the program which used the previously mentioned techniques. Z he experiments' results indicated that these techniques are very useful for computer game. And they have been confirmed by a series of competitions and tests. By these researches, a high-level game system can be produced and the results and conclusions of this paper also have some reference values to other computer game procedures.

关键词： Computer Game minimax algorithm Alpha-Beta Pruning Hash Table Evaluation

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Timing Synchronization algorithm of Large Range Roll-down Coefficient of Oscilloscope 66

Timing Synchronization Algorithm of Large Range Roll-down Co...

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66th IEEE AUTOTESTCON Conference

作者： Wang, Shuo Yang, Kuojun Chen, Li Zhang, Qinchun Ye, Peng Univ Elect Sci & Tech China Sch Automat Engn Chengdu Peoples R China

ISBN: (纸本)9798350300284

Vector signal analysis requires digital down-conversion, low-pass filtering, matching filtering, timing synchronization, carrier synchronization, equalization and other modules. Timing synchronization is the key to vector signal analysis. Traditional timing synchronization, such as Gardner feedback algorithm, has self-noise. The method to reduce self-noise is to design a pre-filter for a specific roll down coefficient before timing synchronization. However, these methods need to redesign the pre-filter coefficient when the roll down coefficient changes, so the signal roll down coefficient can't meet the test requirements when the signal roll down coefficient changes in a wide range. Therefore, this paper proposes a timing synchronization algorithm based on Farrow structure FIR pre-filter. The sub-filter coefficients of Farrow structure of pre-filter are solved offline by minimax algorithm. Pre-filter redesign can be avoided according to different roll down coefficients. The proposed pre-filtering algorithm can be used in vector signal analysis modules with roll down coefficients ranging from 0.1 to 1 and symbol rates ranging from 1kBaud to 8GBaud. The experimental results show that the modulated signal can be demodulated successfully in the range of 0.1-1 roll down coefficient, and the timing jitter can be reduced by 2-3 orders of magnitude when the signal-to-noise ratio(SNR) is greater than 20dB.

关键词： Symbol timing synchronization Farrow filter minimax algorithm

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Generalized Game Trees and their Evaluation 5

Generalized Game Trees and their Evaluation

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5th IEEE International Conference on Cognitive Infocommunications (CogInfoCom)

作者： Basbous, Raed Nagy, Benedek Eastern Mediterranean Univ Dept Appl Math & Comp Sci Gazimagusa Cyprus Al Quds Open Univ Informat & Commun Technol Ctr Jerusalem Israel Univ Debrecen Fac Informat Dept Comp Sci Debrecen Hungary

ISBN: (纸本)9781479972807

Expression trees are well-known tools to visualize the syntactical structure of the expressions. They are helpful also in evaluation. Games and game theory form an important field in Artificial Intelligence and it has several connections to Business and Economy. Game trees are used to represent games. In this paper, some types of extensions of game trees are considered using operations, e.g., multiplication, (constrained) addition and the usual minimum and maximum. Evaluation techniques are presented, as well as, various pruning algorithms that can quicken the evaluation in several cases.

关键词： expression trees game trees minimax algorithm shortcut evaluation alpha-beta pruning decision making cuts of trees

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A Nondominated Adversarial Search algorithm for a Three-player Chess Game

A Nondominated Adversarial Search Algorithm for a Three-play...

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17th International Computer Science and Engineering Conference (ICSEC)

作者： Karnjanapoomi, Nathaporn Pramanpol, Pongpol Lertratsamewong, Voratep Chacavarnkitkuln, Torsakuln Rattanajongjittakorn, Vazuthorn Thavaravej, Chaicharn Wattanapornprom, Warin Rodkaew, Yodthong Silpakorn Univ Fac Informat & Commun Technol Phetchaburi Thailand Thai Ocean Ind Co Ltd Dept Informat Syst Res & Dev Bangkok Thailand Univ Thai Chamber Commerce Sch Sci & Technol Dept Compan Animat Bangkok Thailand

ISBN: (纸本)9781467353229

Three-player (3P) chess is a variation of chess game specially designed for three players. The winning condition that the first player will wins if the player captures any of the other's King, arises the playing strategies that a player can form a temporarily alliance with another player or a player can take advantage from the other's attacking to defeat either two of the opponents. This paper proposes a search algorithm called the nondominated adversarial search (NAS) for the three-player chess game which does not only maximize the own score but also minimize the opponents' scores. The experiment shows that the NAS algorithm can take advantage from the other's attacking to win the game.

关键词： three player chess Nondominated sorting minimax algorithm game artificial intelligence

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ON algorithmS AND IMPLEMENTATIONS OF A 4-CHANNEL ACTIVE NOISE CANCELING WINDOW 25

ON ALGORITHMS AND IMPLEMENTATIONS OF A 4-CHANNEL ACTIVE NOIS...

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International Symposium on Intelligent Signal Processing and Communication Systems (ISPACS)

作者： Shi, Chuang Jiang, Nan Li, Huiyong Shi, Dongyuan Gan, Woon-Seng Univ Elect Sci & Technol China Sch Elect Engn Chengdu Sichuan Peoples R China Nanyang Technol Univ Sch Elect & Elect Engn Singapore Singapore

ISBN: (纸本)9781538621592

The active noise canceling window is an application of the multi-channel active noise control (ANC) system, which aims to provide a quiet living environment while preserving the ventilation of the room. In the implementation of the active noise canceling window, the standard multiple-error LMS algorithm demands too much computational power to be handled by a common digital signal processor (DSP). Hence, the minimax algorithm, which minimize the amplitude instead of the power of the noise field, is revisited. The minimax algorithm is compared with the multiple-error LMS algorithm based on numerical simulations of a case (1, 4, 4) ANC system and real-time experiments with floating-point implementations. The simulation and experiment results show that the minimax algorithm has a distinct advantage in reducing the computational complexity but its trade-off is the relatively slow convergence speed.

关键词： Active noise control minimax algorithm multiple-error LMS algorithm active noise canceling window

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