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23rd IEEE International Symposium on a World of Wireless, Mobile and Multimedia Networks (IEEE WoWMoM)

作者： Gao, Xuening Guo, Longkun Liao, Kewen Qilu Univ Technol Dept Comp Sci Jinan Peoples R China Australian Catholic Univ Peter Faber Business Sch Sydney NSW Australia

ISBN: (数字)9781665408769

ISBN: (纸本)9781665408769

Effective monitoring of applications in wireless sensor networks can be underpinned by the multiple coverage problem with unit disks. In the problem, we are given a set of targets T = {t(1), t(2),..., t(n)} distributed in the plane, where t(i) needs to be covered f(t(i)) times for any positive integer f(t(i)). The aim is to place a minimum number of disks, such that all the targets can be covered as desired. In the paper, we first present a 5-approximation algorithm with runtime O(n + m) for m = max(i) {f(t(i))}. Then, we give a theoretically improved 4-approximation algorithm, albeit with an increased time complexity to O(n(2)). In addition, we consider the online setting where targets arrive in sequence and upon each arrival the corresponding coverage disk must be placed. For this setting, we devise an online algorithm with a competitive ratio of 6 and constant update time. To verify aforementioned theoretical findings, numerical experiments are conducted to demonstrate and compare the practical performance of the proposed algorithms.

关键词： Approximation algorithm multiple coverage independent set unit disk

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Efficient approximation algorithms for offline and online unit disk multiple coverage

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COMPUTERS & ELECTRICAL ENGINEERING 2022年第PartB期104卷

作者： Gao, Xuening Guo, Longkun Liao, Kewen Qilu Univ Technol Sch Comp Sci Jinan Peoples R China Australian Catholic Univ Peter Faber Business Sch Discipline Informat Technol Sydney NSW Australia

multiple coverage with unit disks is a problem widely seen in monitoring applications of wireless sensor networks. In this problem, let T = {t1, t2, ... , tn } be a set of targets to be covered (or monitored) which are distributed on the plane. Each target ti is an element of T is required to be covered by f(ti) disks for the purpose of energy efficiency or fault tolerance. The objective is to decide where on the plane to place the disks such that all the targets can be covered with a minimum number of disks. The problem does not admit any polynomial time exact solution as its special case of single coverage with unit disks is already NP-hard. In the paper, we present both offline and online approximation results for the problem where in the online setting disks must be placed upon each arrival of targets. We first give an offline 5-approximation algorithm with linear time and space complexity via exploiting efficient data structures. The algorithm can be easily adapted as an online 5-competitive algorithm. Then, we propose an improved offline algorithm attaining 4-approximation. Finally, we devise an efficient online algorithm with a constant average update time and a competitive ratio of 6. Numerical experiments are also carried out to empirically test and compare our proposed approximation algorithms.

关键词： multiple coverage Disk coverage Approximation algorithm Online algorithm Linear runtime

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A versatile method for target area coverage analysis with arbitrary satellite attitude maneuver paths

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ACTA ASTRONAUTICA 2022年 194卷 242-254页

作者： Wang, Huijiang Bai, Shengzhou Univ Cambridge Dept Engn Trumpington St Cambridge England Beihang Univ Sch Astronaut Beijing 100191 Peoples R China Hong Kong Polytech Univ Fac Engn Hong Kong Peoples R China

The agile Earth observation satellite (AEOS) is rapidly becoming the leading platform in Earth observation missions, as it implements attitude maneuvers and remote sensing simultaneously. However, present methods limit not only its remote sensing coverage to a small area during attitude maneuvering but also its operation to only certain orbit shapes. This paper proposes a new method, namely envelope curves hierarchical overlapping (ECHO), for the target area coverage analysis of an AEOS that implements attitude maneuvers during its mission. This method involves two stages. In the preparation stage, the satellite's instantaneous access area (IAA) is defined and analytically determined by solving the spatial equations of an oblate Earth and the sensor's view field. Then, the coverage belt of an AEOS is delineated by the envelope curves of a set of IAAs. In the manipulation stage, the coverage problem of a target area is solved by iteratively using the polygon clipping technique and hierarchically taking the intersection parts between the coverage belt and the target area. Numerical simulations demonstrate the practicability and high accuracy of the proposed method.

关键词： Target area coverage analysis Agile satellite Attitude maneuver path coverage belt Polygon clipping multiple coverage

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Analysis of the temporal and spatial characteristics of lunar reconnaissance orbiter's orbit error based on multi-coverage narrow angle camera images

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GEO-SPATIAL INFORMATION SCIENCE 2024年

作者： Xie, Bin Liu, Bin Di, Kaichang Zhang, Yifan Wang, Biao Zhao, Chenxu Chinese Acad Sci Aerosp Informat Res Inst State Key Lab Remote Sensing Sci Beijing Peoples R China Univ Chinese Acad Sci Beijing Peoples R China

Photogrammetric mapping of large area of the lunar surface using high-resolution orbiter images is very challenging due to increasing spatial resolution and lack of a comprehensive understanding of orbit error characteristics. The Lunar Reconnaissance Orbiter (LRO) Narrow Angle Camera (NAC) images are currently one of the highest-resolution images of the Moon available. The study of LRO orbit errors from the perspective of mapping applications is important for high accuracy mapping of large areas using NAC images. This paper proposes a method for orbit error estimation using multi-coverage NAC images. First, available NAC images covering the study regions are orthorectified using ISIS. Then, the impact crater feature matching algorithm is used to match the multi-coverage images. Finally, estimation of the orbit error is achieved through statistical analysis of a large number of homologous points obtained from the matching. The orbit error analyses of nine representative regions on the Moon show that in most cases the refined ephemeris provided by the LOLA/GRAIL team can significantly reduce the orbit error. The orbit errors show a sawtooth variation with a period of about one year, which have been stable for a long time and tend to increase slightly in recent years. There is a slight variation of the orbit error in space, which is even less obvious when using the refined ephemeris. The general tendency is for the far side to be larger than the near side at the same latitude, and for the higher latitudes to be larger than the lower latitudes. The proposed method and analysis results provide a reference for selection and processing of multi-coverage LROC NAC images for high-resolution large-area mapping.

关键词： Orbit error LRO NAC image multiple coverage geo-positioning deviation

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multiple Nodes Co-Carrier Cooperative Transmission in LEO Communication Networks: Developing the Diversity Gain of Satellites

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SENSORS 2024年第14期24卷 4533页

作者： Li, Tian Li, Guoyan Yue, Xinwei Dai, Bin 54th Res Inst China Elect Technol Grp Corp Shijiazhuang 050081 Peoples R China Beijing Informat Sci & Technol Univ Sch Informat & Commun Engn Beijing 100101 Peoples R China Nanjing Univ Posts & Telecommun Sch Internet Things Nanjing 210003 Peoples R China

Low Earth orbit (LEO) satellite communication (SATCOM) networks have gradually been recognized as an efficient solution to enhance ground-based wireless networks. As one of the main characteristics of LEO SATCOM, the beam-edge area could be covered by multiple satellite nodes. In this case, user terminals (UTs) located at the beam-edge have the chance to connect one or more LEO satellites. To develop the diversity gain of multiple nodes in the overlapping area, we propose two high spectral efficiency cooperative transmission strategies, i.e., directly combining (DC) and selection combining (SC). In the DC scheme, signals arrived at the UT simultaneously could be combined into one enhanced signal. For downlink time division multiplexing, the SC scheme enables the UT to select the strongest signal path. Further, as there exists a significant channel gain difference of the beam-center and beam-edge areas, UTs in these two areas can be allocated in one resource block. In this case, we derive co-carriers based on DC and SC, respectively. To deeply analyze the novel methods, we study the ergodic sum-rate and outage probability while the outage diversity gain is further provided. Simulation results show that the co-carrier-based DC method has the ability to provide a higher ergodic sum-rate while the SC method performs better in terms of the outage probability.

关键词： LEO communication networks cooperative transmission co-carrier transmission multiple coverage

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Emergency Material Reserve Location Research in Urban Areas Based on the Supply and Demand Perspective: A Case from China

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Journal of Computer and Communications 2022年第3期10卷 29-45页

作者： Feifei Wang Lin Wang Yunxian Hou College of Economics & Management Anhui Agricultural University Hefei China School of Management Henan University of Technology Zhengzhou China College of Economics and Management China Agricultural University Beijing China

In order to improve the scientific layout of urban emergency material reserve, first, considering that the road condition has an important impact on the effect of emergency rescue, the concept of road damage risk factor is introduced in this article to build satisfaction attenuation function based on the thought of demand satisfaction decreasing within the coverage radius;second, based on the maximum coverage model, a multi-objective and multi-repeated cover model was established to solve the limited supply capacity of emergency supplies reserve;finally, the model is verified by using Yanqing district in Beijing. The study’s results showed that the improved maximum coverage model can scientifically determine the coverage and quantity of emergency supplies of each emergency material reserve, and improve the efficiency and scientificity of emergency supplies distribution. In order to avoid the disorderly distribution of emergency supplies, it is suggested that the coverage radius and scope of the emergency material reserve should be determined based on the balance between supply and demand.

关键词： Emergency Supplies Repository multiple coverage Location Network Design

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A Heuristic Algorithm for the Set k-Cover Problem 3rd

A Heuristic Algorithm for the Set k-Cover Problem

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3rd International Conference on Optimization and Learning (OLA)

作者： Salehipour, Amir Univ Technol Sydney Sch Math & Phys Sci Sydney NSW Australia

ISBN: (纸本)9783030419134;9783030419127

The set k-cover problem (SkCP) is an extension of the classical set cover problem (SCP), in which each row needs to be covered by at least k columns while the coverage cost is minimized. The case of k = 1 refers to the classical SCP. SkCP has many applications including in computational biology. We develop a simple and effective heuristic for both weighted and unweighted SkCP. In the weighted SkCP, there is a cost associated with a column and in the unweighted variant, all columns have the identical cost. The proposed heuristic first generates a lower bound and then builds a feasible solution from the lower bound. We improve the feasible solution through several procedures including a removal local search. We consider three different values for k and test the heuristic on 45 benchmark instances of SCP from OR library. Therefore, we solve 135 instances. Over the solved instances, we show that our proposed heuristic obtains quality solutions.

关键词： Set cover problem multiple coverage Heuristic

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coverage Reduction: A Mathematical Model

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JOURNAL OF ADVANCED MANUFACTURING SYSTEMS 2018年第3期17卷 317-331页

作者： Obredor-Baldovino, Thalia Barcasnegras-Moreno, Evis Mercado-Caruso, Nohora Salas-Navarro, Katherinne Sana, Shib Sankar Univ Costa Dept Ind Engn Barranquilla Colombia Univ Costa Dept Elect Engn Barranquilla Colombia Bhangar Mahavidyalaya Dept Math Bhangar 743502 South 24 Pargan India

This paper deals with a mathematical model for reduction of the lack of coverage (LC) involving multiple coverage in presence of partial covering. The model proposes a new structure of assignment of facilities in a facility location system to cover in greater proportion of the demand territory, avoiding assignment of several facilities in the same space of the territory. A comparison between the engendered solution and its representation is carried out through known indicators to measure the improvement of the solution. The results of our proposed model are contrast and better compared to defined referred models in order to evaluate the reduction of LC.

关键词： Integer programming facility location lack of coverage reduction multiple coverage

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Research on multiple coverage and Connectivity for Wireless Sensor Network

Research on Multiple Coverage and Connectivity for Wireless ...

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The 6th International Conference on Computer Science & Education(第六届国际计算机新科技与教育学术会议 ICCSE 2011)

作者： Wang Jianzhen Guan Zhiyan Department of Information Engineering Business College of Shanxi University Taiyuan China

coverage and connectivity are the key research questions in wireless sensor networks, the relationship of which is very closely. One of the traditional methods for solving coverage and connectivity is integer programming algorithm, whose research background is homogeneous wireless sensor networks and single coverage. The method can not satisfy the requirements in actual high-precision target detection. This paper establishes one kind of network model randomly generated and abstract the mathematical structure the from the model. In addition, achieved a lot of simulation experiments, and obtained the relationship between sensor probability and the number of nodes and the probability curve of simply connectivity, reconnectivity. This paper can provide a reference value for the arrangement of the nodes.

关键词： wireless sensor network multiple coverage simply connectivity re-connectivity

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Time-dependent ambulance allocation considering data-driven empirically required coverage

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HEALTH CARE MANAGEMENT SCIENCE 2015年第4期18卷 444-458页

作者： Degel, Dirk Wiesche, Lara Rachuba, Sebastian Werners, Brigitte Ruhr Univ Bochum D-44801 Bochum Germany

Empirical studies considering the location and relocation of emergency medical service (EMS) vehicles in an urban region provide important insight into dynamic changes during the day. Within a 24-hour cycle, the demand, travel time, speed of ambulances and areas of coverage change. Nevertheless, most existing approaches in literature ignore these variations and require a (temporally and spatially) fixed (double) coverage of the planning area. Neglecting these variations and fixation of the coverage could lead to an inaccurate estimation of the time-dependent fleet size and individual positioning of ambulances. Through extensive data collection, now it is possible to precisely determine the required coverage of demand areas. Based on data-driven optimization, a new approach is presented, maximizing the flexible, empirically determined required coverage, which has been adjusted for variations due to day-time and site. This coverage prevents the EMS system from unavailability of ambulances due to parallel operations to ensure an improved coverage of the planning area closer to realistic demand. An integer linear programming model is formulated in order to locate and relocate ambulances. The use of such a programming model is supported by a comprehensive case study, which strongly suggests that through such a model, these objectives can be achieved and lead to greater cost-effectiveness and quality of emergency care.

关键词： Emergency medical services Ambulance location and relocation Time-dependent data Dynamic adaption multiple coverage Data-driven optimization

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