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An Iterative threshold algorithm of Log-Sum Regularization for Sparse Problem

IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 2023年第9期33卷 4728-4740页

作者： Zhou, Xin Liu, Xiaowen Zhang, Gong Jia, Luliang Wang, Xu Zhao, Zhiyuan Natl Univ Def Technol Coll Informat & Commun Wuhan 430010 Peoples R China Hubei Univ Technol Sch Comp Sci Wuhan 430068 Peoples R China Space Engn Univ Sch Space Informat Beijing 101400 Peoples R China

The log-sum function as a penalty has always been drawing widespread attention in the field of sparse problems. However, it brings a non-convex, non-smooth and non-Lipschitz optimization problem that is difficult to tackle. To overcome the problem, an iterative threshold algorithm for the sparse optimization problems with log-sum function is proposed in this paper. For brevity, the sparse optimization problems with log-sum function are named log-sum regularization. Firstly, by introducing an intermediate function to construct another new function, a property theorem about solution for log-sum regularization is established. Secondly, based on the above theorem, the optimal setting rules of the compromising parameters are elaborated, and an iterative log-sum threshold algorithm is proposed. Thirdly, under the situation that the compromising parameters of log-sum regularization are relatively small, it can be proven that the proposed algorithm converges to a local minimizer of log-sum regularization. Finally, a series of simulations are implemented to examine performance of the proposed algorithm, and the results exhibit that the proposed algorithm outperforms the state-of-the-art algorithms.

关键词： Sparsity compressive sensing threshold algorithm half regularization hard regularization soft regularization log-sum regularization

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Fault diagnosis of a selective compliance assembly robot arm manipulator based on the end joint motion analysis: threshold algorithm and experiments

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TRANSACTIONS OF THE INSTITUTE OF MEASUREMENT AND CONTROL 2018年第5期40卷 1691-1700页

作者： Xu, Fengyu Yang, Zhong Hu, JinLong Jiang, Guoping Dai, GuoHong Nanjing Univ Posts & Telecommun Sch Automat Nanjing 210003 Jiangsu Peoples R China Jiangsu Key Lab Recycling & Reuse Technol Mech & Changshu Jiangsu Peoples R China Jiangsu Yangli CNC Machine Tools Co Ltd Yangzhou Jiangsu Peoples R China

This paper presented a method to carry out fault diagnosis via analyzing the motion signals of a SCARA. To analyze the motion signals of the end joint of a selective compliance assembly robot arm (SCARA) and carry out fault diagnosis. A model parameter-based threshold algorithm is proposed in this study to improve the efficiency of the fault diagnosis on the end joint of a SCARA manipulator. The operation state of the robot is determined by comparing the speed curve of the end joint of the robot with the threshold using the proposed algorithm. Firstly, the threshold range of the system output is estimated using the speed observer constructed via parameter separation. Secondly, the acceleration signals of the end joint of the robot are collected at various operational angular speeds by a single acceleration sensor installed at the end joint of the manipulator. The operation state of the robot is evaluated by analyzing the trend and vibration characteristics of its acceleration. Finally, experiments are conducted at three different speeds: 2.4rad/s, 3.12rad/s and 3.6rad/s. Some robot malfunctions are detected by comparing the actual speed with the threshold. Thus, the proposed method can be used to monitor the variation signal in each robot joint through a single accelerometer mounted on the top of the manipulator.

关键词： Manipulator fault diagnosis threshold algorithm acceleration trend

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Making the threshold algorithm access cost aware

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IEEE TRANSACTIONS ON KNOWLEDGE AND DATA ENGINEERING 2004年第10期16卷 1297-1301页

作者： Lang, CA Chang, YC Smith, JR IBM Corp Thomas J Watson Res Ctr Yorktown Hts NY 10598 USA

Assume a database storing N objects with d numerical attributes or feature values. All objects in the database can be assigned an overall score that is derived from their single feature values (and the feature values of a user-defined query). The problem considered here is then to efficiently retrieve the k objects with minimum (or maximum) overall score. The well-known threshold algorithm (TA) was proposed as a solution to this problem. TA views the database as a set of d sorted lists storing the feature values. Even though TA is optimal with regard to the number of accesses, its overall access cost can be high since, in practice, some list accesses may be more expensive than others. We therefore propose to make TA access cost aware by choosing the next list to access such that the overall cost is minimized. Our experimental results show that this overall cost is close to the optimal cost and significantly lower than the cost of prior approaches.

关键词： multifeature query threshold algorithm adaptive cost-awareness

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Exploring energy landscapes at the DFTB quantum level using the threshold algorithm: the case of the anionic metal cluster Au20^-

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THEORETICAL CHEMISTRY ACCOUNTS 2021年第7期140卷 1-12页

作者： Rapacioli, Mathias Schoen, J. Christian Tarrat, Nathalie Univ Toulouse Ups CNRS Bat 3R1b4118 Route Narbonne F-31062 Toulouse 09 France Max Planck Inst Solid State Res Heisenbergstr 1 D-70569 Stuttgart Germany Univ Toulouse CNRS CEMES 29 Rue Jeanne Marvig F-31055 Toulouse France

We report the combination of the threshold algorithm with the Density Functional-based Tight Binding method allowing for the exploration of complex potential energy surfaces and the evaluation of probability flows between their regions, at the quantum level. This original scheme is used to explore the energy landscape of an anionic 20-atom gold cluster, Au-20(-). On the basis of the relevant structures, 19 structural groups are highlighted, all of them being variations about the pyramidal shape: (1) distorted pyramids, (2) pyramids in which the atom of one of the facets has been removed, leaving a hole, and placed at different positions on the cluster and (3) pyramids on which an atom located at a vertex has been removed and placed on an edge or on a facet. Upper limits of the energies required to connect the basins of the 19 groups on the potential energy surface are evaluated. Moreover, the attractive basins are identified on the basis of the analysis of the probability flows on the landscape. The comparison of the disconnectivity tree with the results of the flux analysis provides a consistent representation of the Au-20(-) basins' proximity. Finally, we show how the new scheme allowed for the identification of counter-intuitive transition pathways.

关键词： Gold clusters threshold algorithm DFTB Energy landscape Probability flows Disconnectivity tree

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A threshold algorithm in a Fall Alert System for Elderly People 5

A Threshold Algorithm in a Fall Alert System for Elderly Peo...

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5th International Conference on the Development of Biomedical Engineering in Vietnam

作者： Pham Ty Phu Nguyen Thanh Hai Nguyen Thanh Tam HCMC Univ Tech Educ Fac Elect Elect Engn Ho Chi Minh Vietnam Int Univ HCMC VNU Dept Biomed Engn Ho Chi Minh City Binh Duong Vietnam

ISBN: (纸本)9783319117768;9783319117751

Falls more likely happen with elderly people due to weak body. These falls may possibly cause serious injuries. Therefore, recognition of early falling for diagnosis and treatment is very important. In this paper, a fall alert system using an accelerometer sensor for elderly people based on a threshold algorithm is applied. A triaxial accelerometer sensor worn on the waist of people is employed to collect acceleration data. A threshold is determined by analyzing the difference between the normal daily activity and the fall. Data is collected from four daily activities and two falls: sit, stand, lie, walk, fall (walk) and fall (chair). This research potentially supports an enhanced understanding on the design and implementation of high-performance fall detections.

关键词： fall detection elderly people threshold algorithm human activity recognition

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Optimized threshold algorithm of Envisat Waveform Retracking over Coastal Sea

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Chinese Journal of Geophysics 2013年第2期53卷 231-239页

作者： Jin-Yun GUO Yong-Gang GAO Xiao-Tao CHANG Cheinway HWANG College of Geodesy and Geomatics Shandong University of Science and Technology Qingdao 266510 China Key Laboratory of Surveying and Mapping Technology on Island and Reef of SBSM Qingdao 266510 China College of Environment and Resources Fuzhou University Fuzhou 350108 China Chinese Academy of Surveying and Mapping Beijing 100039 China Department of Civil Engineering National Chiao Tung University Hsinchu 300 China

Waveform retracking is an effective method to improve the accuracy of sea surface height measurement with the satellite altimetric technique. The improved threshold retracking algorithm is optimized in the paper. Several waveform retracking algorithms such as the 5- β parametric fitting algorithm, off center of gravity, Ocean1 and threshold are also analyzed at the same time. Then a waveform retracking system is programmed. Several retracking methods are used to retrack the EnviSat waveform over the Mediterranean Sea. The optimized threshold retracking algorithm is the more robust retracking method and more suitable for the EnviSat waveform retracking over the coastal Med.

关键词： EnviSat Satellite altimetry Waveform retracking threshold algorithm

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Evolutionary algorithm and threshold accepting algorithm for scheduling in two-machine flow shop with lot streaming

Evolutionary algorithm and Threshold accepting algorithm for...

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IEEE Conference on Cybernetics and Intelligent Systems

作者： Marimuthu, S Ponnambalam, SG Suresh, RK KLN Coll Engn Dept Engn Mech Madurai 630611 Tamil Nadu India

ISBN: (纸本)0780386434

In this paper, two different approaches have been proposed for solving two machine flow shop problems with multiple jobs requiring lot streaming with the objectives of minimizing the makespan and the total flow time of jobs. A population based evolutionary algorithm that involves evolution during the search process and a single point local search metaheuristics that work on a single solution are proposed. The population based approach employs local search, after the genetic search is over, to improve the effectiveness of the search procedure and hence it is called hybrid evolutionary algorithm (HYBRID). A threshold accepting algorithm (TA) proposed in this paper is a single point local search metaheuristic. A job here implies many identical items. Lot streaming creates sub lots to move the completed portion of a production sub lots to down stream machine. Proposed algorithms are evaluated using a set of randomly generated test problems. Experimental results are presented for comparison.

关键词： flow shop threshold algorithm Lot Streaming scheduling

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The diversity in dairy cattle reticulorumen temperature: Identifying water intake events

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COMPUTERS AND ELECTRONICS IN AGRICULTURE 2025年 235卷

作者： Shirley, A. K. Thomson, P. C. Chlingaryan, A. Clark, C. E. F. Univ Sydney Sch Life & Environm Sci Livestock Prod & Welf Grp Camden NSW 2570 Australia Univ Sydney Sydney Sch Vet Sci Camden NSW 2570 Australia Charles Sturt Univ Gulbali Inst North Wagga Wagga NSW 2650 Australia

Climate change and associated weather variability across the Australian landscape has lent themselves to an increased incidence of cattle heat stress. Water consumption can have a sizeable, sustained impact on reticulorumen temperature readings, thereby impacting our interpretation of an individual's underlying physiological response to changing environmental conditions. To distinguish drinking events, we developed a drinking event detection model based on observed drinking events (video recording) from 28 dairy heifers, alongside sensorderived reticulorumen temperature (smaXtec Animal Care GmbH) profiles. The optimised model identified drinking events with high accuracy (F-score = 0.99), as predicted when the average reticulorumen temperature declined by at least 0.5 degrees C per 10-minutes, over a 10-, 20-, or 30-minute period. To account for differences in rapidity of decline, smaller reductions of 0.25 degrees C per 10 min were considered valid indicators of a drinking event, provided the 0.5 degrees C per 10-minute threshold was also met in a consecutive observation period. The temporal variability in drinking behaviour for 1,429 lactating dairy cattle across three dairy farms was then determined. Daily drinking events were greater in summer (mean 4.1) than winter (mean 3.3), while the change in reticulorumen temperature with each drinking event was smaller in summer (mean 3.7 degrees C) than winter (mean 4.9 degrees C). Drinking-recovery duration averaged 97.8 min/event. By revealing temporal differences in drinking behaviour for pasture-based dairy cattle, this work provides the basis for an improved understanding of core body temperature diversity.

关键词： Heat stress Drinking behaviour Sensors threshold algorithm Precision agriculture

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HYBRID threshold SOFT DECISION DECODING algorithm

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IEE PROCEEDINGS-COMMUNICATIONS 1994年第3期141卷 126-128页

作者： CHANG, Y WANG, X XIDIAN UNIV XIAN 710071PEOPLES R CHINA

A hybrid threshold soft decision decoding scheme which combines a Chase 2 algorithm with a bit-by-bit decision decoding algorithm is presented. For higher signal-to-noise ratios (SNRs), its behaviour is not inferior to that of the corresponding bit-by-bit decoding algorithm. This scheme can overcome the exponential increase of the test patterns used in the Chase 2 algorithm, as d (the minimum Hamming distance of code) increases.

关键词： SOFT DECISION DECODING algorithm CASE-2 algorithm HYBRID DECODING algorithm threshold algorithm

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Index-based, High-dimensional, Cosine threshold Querying with Optimality Guarantees

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THEORY OF COMPUTING SYSTEMS 2021年第1期65卷 42-83页

作者： Li, Yuliang Wang, Jianguo Pullman, Benjamin Bandeira, Nuno Papakonstantinou, Yannis Megagon Labs 444 Castro StSuite 720 Mountain View CA 94041 USA Purdue Univ Dept Comp Sci 610 Purdue Mall W Lafayette IN 47907 USA Univ Calif San Diego 9500 Gilman Dr San Diego CA 92093 USA

Given a database of vectors, a cosine threshold query returns all vectors in the database having cosine similarity to a query vector above a given threshold theta. These queries arise naturally in many applications, such as document retrieval, image search, and mass spectrometry. The paper considers the efficient evaluation of such queries, as well as of the closely related top-k cosine similarity queries. It provides novel optimality guarantees that exhibit good performance on real datasets. We take as a starting point Fagin's well-known threshold algorithm (TA), which can be used to answer cosine threshold queries as follows: an inverted index is first built from the database vectors during pre-processing;at query time, the algorithm traverses the index partially to gather a set of candidate vectors to be later verified for theta-similarity. However, directly applying TA in its raw form misses significant optimization opportunities. Indeed, we first show that one can take advantage of the fact that the vectors can be assumed to be normalized, to obtain an improved, tight stopping condition for index traversal and to efficiently compute it incrementally. Then we show that multiple real-world data sets from mass spectrometry, natural language process, and computer vision exhibit a certain form of data skewness and we exploit this property to obtain better traversal strategies. We show that under the skewness assumption, the new traversal strategy has a strong, near-optimal performance guarantee. The techniques developed in the paper are quite general since they can be applied to a large class of similarity functions beyond cosine.

关键词： Vector databases Similarity search Cosine threshold algorithm

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