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Variations on the theme of slacks-based measure of efficiency: convex hull-based algorithms

COMPUTERS & INDUSTRIAL ENGINEERING 2021年 159卷 107474-107474页

作者： Xie, Qiwei Zhu, Yuanchang Shang, Haichao Li, Yongjun Beijing Univ Technol Sch Econ & Management Beijing 100124 Peoples R China Univ Sci & Technol China Sch Management Hefei 230026 Peoples R China Hubei Univ Fac Math & Stat Wuhan 430062 Peoples R China

Non-radial data envelopment analysis (DEA) models, such as the slacks-based measure (SBM) model, exert an important role in theoretical research and real applications on efficiency evaluation and improvement. However, those models maximize input and output slacks and may therefore find a rather far projection for each inefficient decision-making unit (DMU). This results in varying performance measures and inconveniences in improving the performance of inefficient DMUs. Tone (2016) proposed a new non-oriented SBM-Max model and several algorithms to overcome such limitations. However, those algorithms were computationally expensive and complicated, limiting their applications to different problems. In the present study, algorithms are proposed based on two convex hull algorithms to make a novel variation of (Tone, 2016) that is easily applicable to different problems. The proposal is based on the constant returns-toscale (CRS) assumption. The algorithms can be further extended based on other assumptions of returns to scale. The used two convex hull algorithms were the Quickhull (Qhull) algorithm and the C++ (ANSI C) implementation of the double description (CDD) algorithm. The proposed algorithms were tested on a dataset from prior literature and a real dataset of Hong Kong hospitals. The results demonstrate that the proposed algorithms are effective for finding a close projection on efficiency evaluation, resulting in improvements in DMUs.

关键词： Data envelopment analysis (DEA) Slacks-based measure (SBM) Quickhull (Qhull) algorithm C plus plus implementation of the double description (CDD) algorithm convex hull algorithm Efficient facets

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Short-Term Congestion Forecasting in Wholesale Power Markets

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IEEE TRANSACTIONS ON POWER SYSTEMS 2011年第4期26卷 2185-2196页

作者： Zhou, Qun Tesfatsion, Leigh Liu, Chen-Ching Iowa State Univ Dept Elect & Comp Engn Ames IA 50010 USA Iowa State Univ Dept Econ Ames IA 50010 USA Univ Coll Dublin Sch Elect Elect & Mech Engn Dublin 2 Ireland

Short-term congestion forecasting is highly important for market participants in wholesale power markets that use locational marginal prices (LMPs) to manage congestion. Accurate congestion forecasting facilitates market traders in bidding and trading activities and assists market operators in system planning. This study proposes a new short-term forecasting algorithm for congestion, LMPs, and other power system variables based on the concept of system patterns-combinations of status flags for generating units and transmission lines. The advantage of this algorithm relative to standard statistical forecasting methods is that structural aspects underlying power market operations are exploited to reduce forecast error. The advantage relative to previously proposed structural forecasting methods is that data requirements are substantially reduced. Forecasting results based on a NYISO case study demonstrate the feasibility and accuracy of the proposed algorithm.

关键词： Congestion forecasting convex hull algorithm load partitioning locational marginal price price forecasting system patterns wholesale power market

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Hydrothermal systems operation planning using a discretization of energy interchange between subsystems

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ELECTRIC POWER SYSTEMS RESEARCH 2016年 132卷 67-77页

作者： Conceicao, Wellington C. Marcato, Andre L. M. Ramos, Tales Pulinho Passos Filho, Joao Alberto Brandi, Rafael B. S. David, Pedro Americo M. S. da Silva Junior, Ivo Chaves Fed Inst Southeastern Minas Gerais Juiz De Fora MG Brazil Univ Fed Juiz de Fora Dept Elect Energy Juiz De Fora MG Brazil Energy Res Co Rio De Janeiro RJ Brazil

This article presents an alternative approach to solve hydrothermal systems operation planning based on stochastic dynamic programming. Under the presented approach, the hydroelectric power plants are grouped into equivalent subsystems of energy and the expected cost functions are modeled by a piecewise linear approximation, by means of the convex hull algorithm. Also, under this methodology, the problem is solved independently for each subsystem such that the state variables to be considered are the energy storage and energy net interchange of the subsystem. The presented results have shown that this subsystems separation technique reduces significantly the computation time when compared with the traditional techniques of stochastic dynamic programming, demonstrating the effectiveness of the proposed methodology. (C) 2015 Elsevier B.V. All rights reserved.

关键词： Operation planning Stochastic dynamic programming convex hull algorithm Equivalent systems of energy Energy interchange Hydrothermal dispatch

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Range-Spread Target Detection Based on Cross Time-Frequency Distribution Features of Two Adjacent Received Signals

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IEEE TRANSACTIONS ON SIGNAL PROCESSING 2009年第10期57卷 3733-3745页

作者： Shui, Peng-Lang Liu, Hong-Wei Bao, Zheng Xidian Univ Natl Lab Radar Signal Proc Xian 710071 Peoples R China

High resolution radars (HRRs) transmit a wideband signal to achieve a high range resolution. A target is considered as composed of multiple scatterers, which occupy or spread in multiple radar range cells with several scatterers in each cell. Therefore, the refection of a target spreads in multiple range cells in the received signal, which contains more information of target than that obtained from low resolution radars. The target in high resolution radar systems is a range-spread target. The range-spreading or echo features of target are utilized for target detection and identification. The echoes of target are convolutions of transmitted signals with target range-scattering functions dependent on the gesture of target to the line of radar sight. A single echo is used in the conventional detection. It is difficult for target detection and identification in low signal-to-noise ratio (SNR) condition. In this paper, we propose a new range-spread target detection scheme exploiting the image features of cross time-frequency distribution (TFD) of a pair of adjacent received signals. After dechirping, the received signal reflected from target consists of multiple sinusoidal components due to its multiple scatterers when a linear frequency modulated (LFM) signal is transmitted from radar. Some regular image patterns or features of target appear in the cross TFD of two adjacent received signals, while the cross TFD of two independent Gaussian noises does not show such patterns. The cross TFD features are exploited in the proposed scheme. Three steps are composed in the proposed scheme. Firstly, a cross smoothed-pseudo Wigner-Ville distribution (CSPWVD) is made for two adjacent received signals to generate a two-dimensional (2-D) TF image. Then, some regular geometric patterns are detected and extracted from the image. At last, two features of the extracted geometric patterns are jointly utilized to detect target. The proposed algorithm is verified by using raw radar data.

关键词： convex hull algorithm CSPWVD high resolution radar high resolution range profile (HRRP) morphological filtering range-spread target detection

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REACHABLE GRASPS ON A POLYGON OF A ROBOT ARM: FINDING convex ROPES WITHOUT TRIANGULATION

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INTERNATIONAL JOURNAL OF ROBOTICS & AUTOMATION 2010年第4期25卷 304-310页

作者： Phan Thanh An Inst Super Tecn CEMAT P-1049001 Lisbon Portugal Inst Math Hanoi 10307 Vietnam

The convex rope problem, posed by Peshkin and Sanderson in IEEE Journal of Robotics & Automation, 2, 1986 53-58, is to find the counterclockwise and clockwise convex ropes starting at the vertex a and ending at the vertex 6 of a simple polygon, where a is on the boundary of the convex hull of the polygon and b is visible from infinity (i.e., there exists a ray m beginning at b. which does not intersect P anywhere else). Computation of these convex ropes is required to plan reachable grasps of a simple polygon by a simple robot arm. In this paper, we present a linear-time algorithm for solving this problem without, resorting to a linear-time triangulation algorithm and without resorting to a convex hull algorithm for the polygon. The counterclockwise (clockwise, respectively) convex rope consists of two polylines obtained in a basic incremental strategy described in convex hull algorithms for the polylines forming the polygon from a to b. The key idea is the use of Melkman's linear-time convex algorithm for a polyline which loses its simplicity on the ray (m) over bar, beginning at b and in the opposite direction to m (such polyline is constructed by vertices inside the last convex hull in the incremental strategy and being left or on (m) over bar). Some advantages of the algorithm and numerical examples are presented.

关键词： Geometric computing shortest paths the convex rope convex hull algorithm convex hull robotics

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A rapid path-length searching procedure for multi-axial fatigue cycle counting

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FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES 2012年第6期35卷 556-571页

作者： Wei, Z. Dong, P. Tenneco Oil Co Inc Emiss Control Struct Anal Team Grass Lake MI 49240 USA Univ New Orleans Sch Naval Architecture & Marine Engn New Orleans LA 70148 USA

In this paper, a series of advanced searching algorithms have been examined and implemented for accelerating multi-axial fatigue cycle counting efforts when dealing with large time histories. In a computerized calculation of the path-length dependent cycle counting method, most of the central processor unit's (CPU) time is spent on searching for the maximum range or distance in a stress or strain space. A brute-force search is the simplest to implement, and will always find a solution if it exists. However, its cost, in many practical problems, tends to grow exponentially as the size of the loading spectrum increases with a search time measured in the order of O(n2), where n is the number of spectrum data points. In contrast, a form of Andrew's monotone chain algorithm, as demonstrated in this paper, can remarkably reduce the solution time to the order of O(n log n). The effectiveness of the new path-length searching procedure is demonstrated by a series of worked examples with a varying degree of non-proportionality in multi-axial loading history.

关键词： convex hull algorithm cycle counting multi-axial fatigue variable amplitude loading out-of-phase loading path-dependent fatigue damage

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Energy Efficient and Accurate Monitoring of Large-Scale Diffusive Objects in Internet of Things

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IEEE COMMUNICATIONS LETTERS 2017年第3期21卷 612-615页

作者： Oh, Seungmin Lee, Jeongcheol Park, Soochang Univ Calif Los Angeles Dept Comp Sci Los Angeles CA 90095 USA Hong Kong Univ Sci & Technol HKUST NIE Social Media Lab Hong Kong Hong Kong Peoples R China

Based on distributed sensing via energy-constrained sensor devices, the key of large-scale and shape-dynamic object monitoring is how to reduce communication costs, which is the highest related factor to energy consumption. For achieving this goal, we propose a novel detection mechanism based on the convex hull algorithm that has a strong aspect for reducing the number of (geographic) sensing points to be transmitted to base stations for figuring out a large-scale object. As the convex hull only could recognize convex shapes, we develop methods to not only detect shape loss being a convex but recovery original boundary. That is, our mechanism could take both low communication cost and high detection reliability of large-scale objects.

关键词： Object detection Internet of Things convex hull algorithm

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Hand pose estimation based on fish skeleton CNN: application in gesture recognition

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JOURNAL OF INTELLIGENT & FUZZY SYSTEMS 2023年第5期44卷 8029-8042页

作者： Zhang, Mingyue Zhou, Zhiheng Tao, Xiyuan Zhang, Na Deng, Ming South China Univ Technol Sch Elect & Informat Engn Guangzhou 510640 Peoples R China South China Univ Technol Key Lab Big Data & Intelligent Robot Guangzhou Peoples R China Guangdong Sci Ctr Guangzhou Peoples R China

The modern world contains a significant number of applications based on computer vision, in which human-computer interaction plays a crucial role, pose estimation of the hand is a crucial approach in the field of human-computer interaction. However, previous approaches suffer from the inability to accurately measure position in real-world scenes, difficulty in obtaining targets of different sizes, the structure of complex network, and the lack of applications. In recent years, deep learning techniques have produced state-of-the-art outcomes but there are still challenges that need to be overcome to fully exploit this technology. In this research, a fish skeleton CNN (FS-HandNet) is proposed for hand posture estimation from a monocular RGB image. To obtain hand pose information, a fish skeleton network structure is used for the first time. Particularly, bidirectional pyramid structures (BiPS) can effectively reduce the loss of feature information during downsampling and can be used to extract features from targets of different sizes. It is more effective at solving problems of different sizes. Then a distribution-aware coordinate representation is employed to adjust the position information of the hand, and finally, a convex hull algorithm and hand pose information are applied to recognize multiple gestures. Extensive studies on three publicly available hand position benchmarks demonstrate that our method performs nearly as well as the state-of-the-art in hand pose estimation. Additionally, we have implemented hand pose estimation for the application of gesture recognition.

关键词： Hand pose estimation FS-HandNet distribution-aware coordinate representation convex hull algorithm the application of gesture recognition

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Arc Grounding Fault Identification Using Integrated Characteristics in the Power Grid

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Energy Engineering 2024年第7期121卷 1883-1901页

作者： Penghui Liu Yaning Zhang Yuxing Dai Yanzhou Sun School of Electrical Engineering and Automation Henan Polytechnic UniversityJiaozuo454003China Research and Development Center Guangdong Zhicheng Champion Group Co.Ltd.Dongguan523000China Henan Key Laboratory of Intelligent Detection and Control of Coal Mine Equipment Henan Polytechnic UniversityJiaozuo454003China

Arc grounding faults occur frequently in the power grid with small resistance grounding neutral *** existing arc fault identification technology only uses the fault line signal characteristics to set the identification index,which leads to detection failure when the arc zero-off characteristic is *** solve this problem,this paper presents an arc fault identification method by utilizing integrated signal characteristics of both the fault line and sound ***,the waveform characteristics of the fault line and sound lines under an arc grounding fault are *** that,the convex hull,gradient product,and correlation coefficient index are used as the basic characteristic parameters to establish fault identification ***,the logistic regression algorithm is employed to deal with the reference samples,establish the machine discrimination model,and realize the discrimination of fault ***,simulation test results and experimental results verify the accuracy of the proposed *** comparison analysis shows that the proposed method has higher recognition accuracy,especially when the arc dissipation power is smaller than 2×10^(3) W,the zero-off period is not *** conclusion,the proposed method expands the arc fault identification theory.

关键词： Arc fault convex hull algorithm correlation coefficient fault identification gradient logistic regression

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convex hulls, oracles, and homology

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JOURNAL OF SYMBOLIC COMPUTATION 2004年第4期38卷 1247-1259页

作者： Joswig, M Ziegler, GA Univ Magdeburg Fak Math Inst Algebra & Geometrie D-39106 Magdeburg Germany Tech Univ Berlin Math Inst D-10623 Berlin Germany

This paper presents a new algorithm for the convex hull problem, which is based on a reduction to a combinatorial decision problem COMPLETENESSC, which in turn can be solved by a simplicial homology computation. Like other convex hull algorithms, our algorithm is polynomial (in the size of input plus output) for simplicial or simple input. We show that the "no"-case Of COMPLETENESSC has a certificate that can be checked in polynomial time (if integrity of the input is guaranteed). (C) 2004 Elsevier Ltd. All rights reserved.

关键词： convex hull algorithm simplicial homology computation

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