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From past the development direction of logistics centers covering problem, the main solution is almost always relying on modern computer and gradually developed intelligent algorithm, at the same time, the previous understanding of dynamic covering location model is not "dynamic", in order to improve the unreasonable distribution of logistics centers deployment time, improve the service coverage, coverage as the optimization goal to logistics centers, logistics centers as well as each one can be free to move according to certain rules of "dot", according to the conditions set by the site moved to a more reasonable. The innovation of all algorithms in this paper lies in that the logistics centers themselves are regarded as the subject of free "activities", and they are allowed to move freely according to these rules by setting certain moving rules. Simulation results show that the algorithm has good coverage effect and can meet the requirements of logistics centers for coverage effect.


Author(s):  
Nour El-Din Safwat ◽  
Fatma Newagy ◽  
Ismail Hafez

In this paper, a new relay system that uses the UAV as a relay station between the tethered UAV and ground user (TU2U2G) is proposed. The TU2U2G system replaces the base station (BS) in the cellular system with a tethered UAV (TUAV). The TUAV is a UAV that receives power over a cable from a ground control station. It has advantages of high and variable altitude up to (100m) compared to BS. In addition, it overcomes the UAV drawback of the batteries' limited capacity. After that, a 3D placement Algorithm of the UAV as a relay station in the TU2U2G system is proposed. It is presented to maximize the coverage by jointly optimizing the transmitting power and relaying distance. The TU2U2G system shows better results than the traditional cellular system in terms of optimum UAV height, maximum coverage radius, and maximum distance between BS and UAV.


Author(s):  
Abdulaziz Saleh Alzahrani ◽  
Ahmad Al Hanbali

The fire station location is a critical decision to optimize the coverage level as measured in terms of the response time. This paper focuses on optimizing the coverage problem, especially in the fire protection field, with new model features to incorporate realistic business challenges such as location criticality and secondary coverage. We extend the deterministic Maximum Coverage Location Problem to account for Top Corporate Risk locations being covered by different fire stations as primary and secondary coverage. To deal with the response time uncertainty arising in practice, we propose a new binary linear problem based on the Maximum Expected Covering Location Problem. By exploiting the model structural characteristics, we prove that the model complexity can be substantially reduced to yield an efficient solution. In the numerical experiments, we use a real case study with five years of historical data. The optimization results of the models yield a priority ranking of the fire stations to open and show the value of incorporating the coverage uncertainty. Finally, we also compare our model with uncertainty with the standard scenario-based optimization to extend the numerical results.


2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Jing Zhang ◽  
Yajing Hu ◽  
Hongliang Li

For smart city wireless sensing network construction needs, a network positioning algorithm based on genetic algorithm is proposed. The genetic algorithm uses a real number encoding, and the positioning model is constructed by analyzing the communication constraint between unknown nodes and a small amount of anchor nodes and constructs the positioning model, and the model is solved. The results show that when the ranging error is 50%, the positioning error is only increased by approximately 15% compared to the nonranging error. In a more harsh environment, if the ranging error is equal to the node wireless range, the ranging error is 100%, and the positioning error and the positioning ratio are not significantly changed. The scheme obtained by this algorithm can be well approarded with an ideal limit. In the case where the sensor node is given, the algorithm can obtain the maximum coverage.


2021 ◽  
Vol 2083 (2) ◽  
pp. 022039
Author(s):  
Yanlin Li

Abstract Unmanned on-board mobile base stations (MBSs) can more effectively solve wireless connectivity problems in terrestrial communication networks without fixed infrastructure. The purpose of this article is to minimize the number of MBS required to provide wireless coverage for a set of distributed ground terminals (GTs). Traditional clustering algorithms are no longer applicable because each drone has a different coverage area size and the traditional K-Means clustering algorithm has no limit on the number of heaps that can exceed the maximum coverage area of a single drone, making it impossible for a drone to provide services. In response to this problem, the traditional K-Means clustering algorithm is optimized, and the results of the optimized K-Means clustering algorithm are stacked to ensure that each pile has the corresponding drone capability to serve it.


2021 ◽  
Author(s):  
Gleb Vladimirovich Kazantsev ◽  
Alexey Igorevitch Ivanov

Abstract This work is devoted to a new direction for geology – interpretation of studied section of sediments through the analysis of microimager data. Imager analysis provides important information about the structural and textural features of rocks, nature of stratification, structural occurrence of the section, natural and technogenic fracturing. The use of borehole microimages in geological and field studies allows us to deepen and expand the existing ideas about the geological structure of known hydrocarbon deposits, and the integrated use of images allows us to solve narrowly focused tasks (Rybalchenko et al., 2016). It is worth to notice that today the potential of reservoir microimagers as a geological GIS tool is underestimated (Isotova et al., 1993) (Mathis et al., 1995) (Donselaar et al., 2005). The most widespread development of borehole imagers abroad occurred in the mid-80s of the XX century. Currently, their use is still gaining popularity in Russia. The use of microimages is not limited to the open trunk of a drilled well, technologies that allow obtaining images directly during drilling are available and widely used (Rybalchenko et al., 2016). From the point of view of well productivity, they can be used to characterize such key parameters as the orientation of horizontal stresses, as well as the intervals of anisotropy, secondary porosity, fracturing and possible crack spread during hydraulic fracturing (Climer et al., 2015). Fine structural and textural features of the section can be used for sedimentological analysis, which means the study of sedimentary rocks in order to establish the processes of their formation - the transport of material, the accumulation of sediments and their diagenetic transformations (Nichols et al., 1999). This analysis is based on the principle of actualism and is carried out using the latest results of studying modern sedimentation processes (Prothero et al., 1996). Imagers are divided into the degree of detail and the scale of measurements:Microimagers – a number of GIS devices, the result of which are images (well scan) with an axial resolution of no more than 1 cm, with a maximum coverage of the wellbore of at least 75% and having a correction for uneven movement and for the intervals of puffs (FMI, FMI-HD, QGEO, QGEO Slim, TBEI of the Wireline division, and also MicroScope HD devices).Imagers – a number of GIS devices, the result of which is images with an axial resolution of no more than 10 cm and/or with a maximum coverage of the wellbore of at least 50%. (FMS, DOBMI, OBMI, UBI divisions of Wireline, and also MicroScope and GeoVISION devices).Macroimagers – a number of GIS devices, the result of which is images (well scan) with an axial resolution of more than 10 cm (geoVISION, EcoScope). Imager - a graphical representation of the walls of the well. It is the result of recording a number of GIS devices. In the diagrams, it is a scan of the cylinder from 0 to 360 degrees, oriented to the cardinal directions relative to the true north or relative to the "top" of the well (Top of Hole). In this paper, authors show the advantages of microimagers over the informativeness of a standard GIS complex and sedimentological core study, and also describes cases when the informativeness of a microimager is not inferior to the informativeness of core data. Authors understand that core is the most important link in the chain of studying the geological structure of the deposit. Nevertheless, it is difficult to characterize the entire interval of the formation using only the core, both for geological and technological reasons. At the same time, imagers can be used not only as a qualitative, but also a quantitative source of visual information (Brown et al., 2015).


2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Silvia A. Centeno ◽  
Dorothy Mahon ◽  
Federico Carò ◽  
David Pullins

AbstractJacques-Louis David’s (1748–1825) iconic portrait of Antoine Laurent Lavoisier (1743–1794) and Marie-Anne Lavoisier (Marie-Anne Pierrette Paulze, 1758–1836) has come to epitomize a modern couple born of the Enlightenment. An analytical approach that combined macro-X-ray fluorescence with the examination and microanalysis of samples by Raman spectroscopy and scanning electron microscopy-energy dispersive X-ray spectrometry to investigate imprecise indications of changes to the composition observed by microscopy and infrared refectography allowed the visualization of a hidden composition with a high level of detail. The results revealed that the first version depicted not the progressive, scientific-minded couple that we see today, but their other identity, that of wealthy tax collectors and fashionable luxury consumers. The first version and the changes to the composition are placed in the context of David’s mastery of the oil painting technique by examining how he concealed colorful features in the first composition by using paint mixtures that allowed for maximum coverage with thin paint layers. The limitations of the analytical techniques used are also discussed. To our knowledge, this is the first in-depth technical study of a painting by J.-L. David.


2021 ◽  
Author(s):  
Gabriela L. Rodriguez-Cortes ◽  
Anabel Martinez-Vargas ◽  
Oscar H. Montiel-Ross ◽  
MA. Cosio-Leon ◽  
Daniela M. Martinez

Algorithmica ◽  
2021 ◽  
Author(s):  
Dror Rawitz ◽  
Adi Rosén
Keyword(s):  

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