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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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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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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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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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Comparative study on threshold selection for measuring characteristics of turbulent swirling flames in a miniature-scale swirl burner

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SIGNAL IMAGE AND VIDEO PROCESSING 2023年第4期17卷 1365-1373页

作者： Sheykhbaglou, Soroush Karami, Shayan Amirkabir Univ Technol Sch Mech Aerosp & Maritime Engn 350 Hafez Ave Tehran Iran Amirkabir Univ Technol Sch Elect Comp & Biomed Engn 350 Hafez Ave Tehran Iran

This study analyzes six threshold approaches for measuring swirling flame properties including flame length, lift-off height, maximum width, area, and flame pulsating displacements in terms of flame center of gravity, length, and width under three operating conditions. Flame video images are captured with the use of a high-speed camera for this objective. The image processing of frames obtained from a high-speed video was fulfilled by utilizing the intermittency distribution approach in order to compare the flame properties quantitatively. The findings show that the Huang technique binarizes the experimental images of the swirling flames the best of the six threshold methods, whereas the Minimum approach produces a large error in flame morphology prediction. After the Huang algorithm, the Yen and Renyi's Entropy-based algorithms do well in forecasting flame morphology, respectively. When compared to the Huang algorithm, the Minimum technique reduces the flame length, maximum width, and area by approximately 34, 26, and 56% for fuel and airflow rates of 0.200 and 3 slpm, respectively. The two approaches of Otsu and Intermodes, on the other hand, yield almost identical flame characteristics. In addition, flame pulsating displacements in terms of center of gravity, length, and width exhibit linear dependency on the fuel flow rate (positive slope), and at a fixed fuel flow rate, pulsating displacement in terms of flame length is larger than pulsating displacement in terms of flame width. In addition, flame pulsating displacement in terms of center of gravity shows the least sensitivity to the fuel flow rate.

关键词： Miniature-scale burner Swirling flame Flame length threshold algorithm Otsu algorithm Huang algorithm Intermittency distribution Flame existence probability Flame pulsating displacement

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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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Improved Energy Management System for Wind Power-Based Microgrid with EV Charge Station

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ELECTRIC POWER COMPONENTS AND SYSTEMS 2024年第10期52卷 1808-1820页

作者： Bekiroglu, Erdal Esmer, Sadullah Bolu Abant Izzet Baysal Univ Dept Elect & Elect Engn Bolu Turkiye Bolu Abant Izzet Baysal Univ Dept Elect & Elect Engn Turkiye TR-14280 Bolu Turkiye

This study aims to peak power shaving and reduce the cost of energy by using improved energy management system (EMS) in a microgrid. This study has three scenarios. In the first scenario, the EV charging station and the wind turbine operate standalone. In the second scenario, a microgrid structure including an energy storage system (ESS) and an EMS is established. The threshold algorithm has been used for the energy management. In the last scenario, fuzzy logic-based EMS is used for energy management. The impact of EV charge station and wind turbine on the grid and the cost of energy are analyzed for three scenarios. The results show that the use of microgrid-connected ESS significantly reduces the cost of energy and creates a more balanced load for the grid side. It is also proved that the EMS affects the energy losses. It is revealed that when the proposed fuzzy logic-based EMS is used, the energy cost is reduced by 78% and the peak power is reduced by 70%. Thus, it is seen that the proposed EMS successfully reduces both the cost of energy and the negative impact of EVs on the grid by balancing grid side load.

关键词： energy management system wind power microgrid EV charge station threshold algorithm fuzzy logic

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Spline retracker: a geometrical retracking algorithm for coastal and open ocean altimetry

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MARINE GEODESY 2024年第2期47卷 83-118页

作者： Mafi, Saleh Farzaneh, Saeed Sharifi, Mohammad Ali Forootan, Ehsan Univ Tehran Coll Engn Sch Surveying & Geospatial Engn Tehran Iran Aalborg Univ Dept Sustainabil & Planning Geodesy Grp Aalborg Denmark

Satellite altimetry has enhanced the understanding of ocean dynamics through high-rate sampling and global coverage. However, land contamination and bad reflection effects limit its accuracy. We present a geometrical method for retracking altimetry waveforms in coastal areas. Our method follows a geometrical assumption related to the symmetrical reciprocal motion of the radar pulse. Based on this assumption, the altimetry waveform is modelled as a continuous and differentiable third-order spline function, and the symmetry point of this function is considered as the retracking gate. The spline retracking algorithm is validated against the tide gauges at Onsala, Halmstad, and Muscat stations in Sweden and Oman, and its performance is compared with existing retracking algorithms. Our results showed a remarkable reduction of 50-91% in the unbiased-Root-Mean-Squared-Error (ubRMSE) and an increase of at least 13% in correlation coefficients when compared with other algorithms in Swedish coast. This algorithm presented equivalent results with the threshold and improved threshold retrackings in Muscat station, based on Jason-2 measurements. However, along the Jason-3 pass, our spline method showed a considerable reduction of 80% in ubRMSE and the minimum increase of 42% in correlation coefficients than the empirical algorithms. This method also outperformed the ALES algorithm in most cases.

关键词： Coastal altimetry OCOG algorithm retracking spline function threshold algorithm

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Design of a Remote Monitoring System for Tool Inventory Based on Multi terminal Control of Server Network Nodes 3

Design of a Remote Monitoring System for Tool Inventory Base...

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3rd International Conference on Energy and Power Engineering, Control Engineering (EPECE)

作者： Fu, Anjun Xu, Zhuojia He, Juliang Sun, Youhao Wu, Dan China Southern Power Grid Digital PowerGrid Techn Guangzhou 510663 Guangdong Peoples R China Guangdong Power Grid Corp Guangzhou 510000 Guangdong Peoples R China

ISBN: (纸本)9798350366105;9798350366099

In order to achieve real-time monitoring and management of tool inventory, design a remote monitoring system for tool inventory based on multi terminal regulation of server network nodes. By establishing server nodes and corresponding multi terminal control modules, the system can achieve load balancing, fault tolerance, and data storage functions. By implementing a threshold algorithm for tool inventory alarm, the inventory quantity of tools can be monitored and judged in real time, and abnormal inventory situations can be detected in a timely manner, triggering an alarm mechanism. At the same time, a hierarchical permission algorithm is adopted for user permission management to improve the data security and information confidentiality of the system. The experimental results show that the system can efficiently manage tool inventory and achieve remote monitoring and control to meet the requirements of real-time and reliability.

关键词： Server Inventory of tools and tools Remote monitoring Network communication threshold algorithm Hierarchy permission 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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