检索结果-内蒙古大学图书馆

Modeling and Analysis of coverage degree and Target Detection for Autonomous Underwater Vehicle-Based System

IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2018年第10期67卷 9959-9971页

作者： Sun, Peng Boukerche, Azzedine Univ Ottawa Sch Elect Engn & Comp Sci Ottawa ON K1N 6N5 Canada

In this article, we theoretically investigate the dynamic aspects of the coverage degree and target detection in the underwater environment resulting from the given moving scenarios of the autonomous underwater vehicles (AUVs). With the help of the continuous moving AUVs, the underwater targets, that cannot be detected by the stationary underwater acoustic sensor network, can be detected with an expected probability, which is determined on the basis of the selected moving scenario of the AUVs. We prove that, for an AUV with randomly selected initial starting point and initial direction, the straight trajectory is the optimal route to achieve the maximum coverage and target detection probability. Then, we present a mathematical model to quantitatively analyze the coverage degree in the underwater environment by using AUVs, as well as formulating the target detection probability of both static target detection and mobile target detection cases. Furthermore, by taking the exposure time of the target into account, we mathematically formulate and analyze the impact of the features of an AUV (i.e., sensing range and velocity) and the moving speed of the mobile target to the mobile target detection probability. We carry out intensive simulation experiments to evaluate the proposed mathematical model, and the experimental results further verify the correctness of our theoretical results.

关键词： Underwater acoustic sensor networks coverage degree autonomous underwater vehicles

来源：评论

学校读者我要写书评

暂无评论

Mobile Crowdsensing coverage degree-Probability Enhancement based on Urban Vehicles

Mobile Crowdsensing Coverage Degree-Probability Enhancement ...

引用

IEEE Global Communications Conference (GLOBECOM) on Advanced Technology for 5G Plus

作者： Ting Liu Wang, Chaowei Gaimu, Xiga Wang, Weidong Beijing Univ Posts & Telecommun Sch Elect Engn Beijing Peoples R China

ISBN: (纸本)9781728182988

Mobile crowdsensing (MCS) is a promising diagram for data collecting based on smart mobile terminal. Nowadays, vehicles with embedded multiple sensors have been increasingly adopted as participants to complete various sensing tasks. Most existing researches are conducted in terms of MCS coverage, energy consumption or incentive mechanisms etc. In this paper, a new utility function F(Omega) for measuring the quality of MCS coverage is proposed, F(Omega) includes coverage percentage and coverage degree. We formulate the selection of taxis as an optimization of coverage quality. Therefore, an improved greedy algorithm to optimize the coverage quality (CQO) is proposed. We evaluate the proposed algorithm with trajectory dataset and study several factors influencing coverage quality. The results show that the proposed algorithm achieves a better coverage quality.

关键词： mobile crowdsensing urban sensing coverage quality coverage degree

来源：评论

学校读者我要写书评

暂无评论

Assessment Method of coverage degree for Pneumatic Sprayers Used in Orchards

引用

Agriculture and Agricultural Science Procedia 2016年 10卷 47-54页

作者： Ovidiu Marian Mircea Valentin Muntean Ioan Drocaş Ovidiu Ranta Adrian Molnar Giorgiana M. Cătunescu Victor Bărbieru University of Agricultural Sciences and Veterinary Medicine Department of Technology and Soil Sciences Calea Manastur 3-5 Cluj Napoca Romania

The use of electronic equipment in plant protection treatments in vineyards and orchards is of great importance both economically and environmentally. In this sense, this paper aims to highlight the importance of spraying equipment in vineyards and orchards. The main goal of this paper was to determine and to evaluate the coverage degree for the Gamberini 500 orchard spraying machine. For the purpose of this paper, the machine Gamberini 500 was used in laboratory conditions to determine and evaluate the coverage degree. This spraying machine is a pneumatic one, with a special boom. In order to evaluate the degree of coverage, a special paper was used, which was placed at different heights (1; 2; 3 m). The paper was scanned, transformed in black and with the MathCad software the degree of coverage was evaluated using the READBMP function. The results obtained showed that the degree of coverage differs with respect to the height. The biggest degree of coverage was obtained at lower heights, due to the small distance to the target. This degree of coverage is mostly influenced by the orientation of the boom, the quantity of water sprayed and the droplets size. In order to achieve a higher degree of coverage it is important to use a fan which has a tower blower, because the distance from boom to target surface is relative equal.

关键词： coverage degree spraying machine MathCad DepositScan

来源：评论

学校读者我要写书评

暂无评论

TiOx/Pd interfacial catalysts with controllable geometrical/electronic effects for industrial H2O2 production

引用

AICHE JOURNAL 2023年第6期69卷 e18049-e18049页

作者： Zhang, Fengyu Miao, Chenglin Wang, Qian Gao, Mingyu Li, Dianqing Feng, Junting Beijing Univ Chem Technol State Key Lab Chem Resource Engn Beijing Peoples R China Beijing Univ Chem Technol Beijing Engn Ctr Hierarch Catalysts Beijing Peoples R China Beijing Univ Chem Technol State Key Lab Chem Resource Engn Box 9815 Bei San Huan East Rd Beijing 100029 Peoples R China

Aiming at controllable modulating metal-support interactions to achieve an optimal trade-off of geometric/electronic effect in supported catalysts, we developed a reliable approach based on the typical 2D material layered double hydroxide (LDHs). A series of TiOx/Pd/MgTiAl-MMO-X catalysts with adjustable interfacial effect were acquired by loading PdCl42- precursor and further preciously adjusting the topological reduction temperature, based on the regulatory effect of Mg-O-Ti-O-Al-O structure in the support on the reducibility and mobility of Ti4+. The catalysts with semi-continuous and accessible TiOx/Pd interface, confirmed by AC-HAADF-STEM, CO chemisorption, XPS, exhibit much higher H2O2 yield than the catalyst with over-encapsulation structure. The TiOx/Pd/MgTiAl-MMO-450 catalysts possessed optimal geometric and electronic structure exhibited the highest activity with TOF of 9.75 s(-1), excellent H2O2 yield of 11.4 g/L, as well as good stability.

关键词： coverage degree hydrogen peroxide interface structure layered double hydroxide tunable metal-support interaction

来源：评论

学校读者我要写书评

暂无评论

Relief making on bearing sleeve surface by eccentric burnishing

引用

JOURNAL OF MATERIALS PROCESSING TECHNOLOGY 2009年第1期209卷 131-138页

作者： Korzynski, Mieczyslaw Rzeszow Univ Technol Mech Engn & Aeronaut Fac PL-35959 Rzeszow Poland

The article describes how to obtain regular depressions in hole surfaces by means of eccentric burnishing. The principle of the method was explained and the mathematical formulae showing the relations among the process parameters were derived. A formula enabling the choice of the rotational speed of the burnishing head with regard to the (required) machining trace coverage of the surface was given. The structure of a head used for eccentric burnishing of bearings sleeves was described. Experiments checking the possibility of making various reliefs confirmed the practical application of the head The investigation of the extent of. g tribological wear of steel/steel and steel/bronze sliding contacts were carried out. It showed explicitly that the specimen with oil pockets obtained by eccentric burnishing show much less wear than diamond turned ones. (C) 2008 Elsevier B.V. All rights reserved.

关键词： Eccentric burnishing Relief making Bearing sleeve coverage degree Oil pockets

来源：评论

学校读者我要写书评

暂无评论

Creation of Bronsted Acidity by Grafting Aluminum Isopropoxide on Silica under Controlled Conditions: Determination of the Number of Bronsted Sites and their Turnover Frequency for m-Xylene Isomerization

引用

CHEMCATCHEM 2014年第3期6卷 832-841页

作者： Caillot, Maxime Chaumonnot, Alexandra Digne, Mathieu Van Bokhoven, Jeroen A. ETH CH-8093 Zurich Switzerland IFP Energies Nouvelles Direct Catalyse & Separat F-69360 Solaize France Paul Scherrer Inst Lab Catalysis & Sustainable Chem LSK CH-5232 Villigen Switzerland

There is not a unique BrOnsted acid site for aluminosilicates (ASAs). IR spectroscopy following CO adsorption proves the creation of BrOnsted acid sites on Al/SiO2 ASAs, which are synthesized by the deposition of aluminum species on hydroxylated silica. These sites are active for ethanol dehydration and m-xylene isomerization. Controlled deposition under anhydrous conditions optimizes the number of sites, whereas the presence of water leads to alumina agglomerates with no BrOnsted acidity. The turnover frequency for m-xylene isomerization (4.3x10(-4)s(-1)site(-1) at 350 degrees C, atmospheric pressure, and 0.6cm(3)h(-1) of m-xylene) is approximately 3times lower than that of the BrOnsted acid sites of Si/Al2O3 and 75times lower than that of an ultrastable Y-type zeolite without extra-framework aluminum.

关键词： acidity coverage degree ethanol silicates thermogravimetry

来源：评论

学校读者我要写书评

暂无评论

EFFICACY OF GRASS FOR MITIGATING RUNOFF AND EROSION FROM AN ARTIFICIAL LOESSIAL EARTHEN ROAD

引用

TRANSACTIONS OF THE ASABE 2010年第1期53卷 119-125页

作者： Liu, G. Tian, F. X. Warrington, D. N. Zheng, S. Q. Zhang, Q. NW A&F Univ State Key Lab Soil Eros & Dryland Farming Loess P Inst Soil & Water Conservat Yangling 712100 Shaanxi Peoples R China China Three Gorges Univ Key Lab Geol Hazards Gorges Reservoir Area 3 Minist Educ Yichang Hubei Peoples R China Lanzhou Univ Key Lab Western Chinas Environm Syst Lanzhou 730000 Peoples R China China Three Gorges Univ Biotechnol Res Ctr Yichang Hubei Peoples R China

Runoff and soil losses from earthen hillside roads are a serious problem on the Loess Plateau in China. We constructed artificial road sections (2.0 m long, 0.55 m wide, 0.35 m deep, 15 degrees slope) with loessial soil packed to give a representative bulk density of 1.5 g cm(-3) and planted with different degrees of grass cover (0%, 30%, 40%, 50%, 60%, or 70%). Simulated rainfall (120 mm h(-1) for 1 h) was applied to the road sections, and we examined the hydraulic characteristics of the overland flow that was generated and the amount of runoff and sediment yield produced over time. Increasing grass cover inhibited overland flow (as indicated by lower Froude and Reynolds numbers), increased friction and surface roughness (as indicated by Manning and Darcy-Weisbach coefficients), and reduced mean flow velocities. Lower impact energies of raindrops intercepted by the grass led to reduced surface seal formation and detachment of soil particles. This in turn resulted in amounts of runoff and sediment from the grassed roads that were 12.4% to 27.9% and 39% to 76% smaller, respectively, than those from the bare roads. Reductions in sediment yields, which were exponentially related to the degree of cover, were also attributable to reduced carrying capacity of the runoff Therefore, grass growing on loessial earthen roads can mitigate soil losses effectively and, to a lesser degree, runoff amounts.

关键词： Artificial rainfall coverage degree Earthen road Hydraulics parameters Runoff and sediment reduction

来源：评论

学校读者我要写书评

暂无评论

coverage Maximization in Wireless Sensor Networks Using Minimal Exposure Path and Particle Swarm Optimization

引用

SENSING AND IMAGING 2020年第1期21卷 1-16页

作者： Bonnah, Ernest Ju, Shiguang Cai, Wenpeng Jiangsu Univ Sch Comp Sci & Telecommun Engn 301 Xuefu Rd Zhenjiang 212013 Jiangsu Peoples R China

The fundamental objective of deploying wireless sensors is to monitor a physical condition(s) within the desired region and relay the measured data to the interested parties through a gateway. However, achieving maximum coverage over the desired area after the initial random deployment of nodes is likely impossible. Arbitrary paths become exposed, uncovered by any of the sensor nodes questioning the quality of service of the network. In our proposed coverage maximization scheme, exposure profiles of sensor nodes were used by the sink node to compute the minimal exposure path. A combination of the computed minimal exposed path and the ratio of covered to uncovered grids were used as the function fitness in our particle swarm optimization algorithm. Bearing in mind the energy constraints of sensor nodes, randomly deployed nodes were only repositioned in the optimization process when their energy levels are above the predefined threshold. The accuracy and efficiency of our scheme are established via simulations. We compared the results of our scheme with a similar optimization scheme. The results showed our scheme achieved a higher coverage degree with the same number of deployed nodes over a region of interest of the same size.

关键词： Wireless sensor networks Minimal exposure path coverage degree Energy constraints Particle swarm optimization

来源：评论

学校读者我要写书评

暂无评论

Extraction of maize canopy temperature and variation factor analysis based on multi-source unmanned aerial vehicle remote sensing data

引用

EARTH SCIENCE INFORMATICS 2024年第6期17卷 5079-5094页

作者： Zhai, Liting Yang, Wenpan Li, Changchun Ma, Chunyan Wu, Xifang Zhang, Ruilong Guangdong Aerosp Hongtu Informat Technol Co Ltd Guangzhou 510000 Peoples R China Henan Polytech Univ Sch Surveying & Land Informat Engn Jiaozuo 454000 Henan Peoples R China

Canopy temperature is an important parameter for monitoring the physiological status of maize. The study of its change law can help to improve the growth environment and increase the yield and quality. Based on the RGB, thermal infrared, and multispectral images obtained by an Unmanned Aerial Vehicle (UAV), two peak threshold methods were used in this study to eliminate the soil background and obtain the maize canopy information in the study area. Then, by using the radiation transmission model and Planck's law, the maize canopy temperature was extracted, and the correlation of canopy temperature change with the regional coverage and soil drought degree was analysed. Results indicated that the accuracy of canopy temperature extraction can be effectively enhanced by eliminating the influence of soil background. At jointing and filling stages, the Pearson correlation coefficients r of canopy temperature and coverage were 0.731 and 0.722, respectively, and the slope of the linear fitting model was less than 0, indicating that the coverage has a negative impact on canopy temperature, i.e., the higher the coverage, the lower the canopy temperature, and vice versa. Additionally, statistical analysis of the canopy temperature and temperature vegetation drought index (TVDI) clustering results at the jointing and filling stages demonstrated that the total overlapping rates of the categories were 72.5% and 41.0% respectively, suggesting that maize canopy temperature is related to regional soil drought degree, the change range of canopy temperature increases with the TVDI value, and the soil drought degree at the jointing stage has a large impact on maize canopy temperature change than that at the filling stage. This study provides technical support for extracting and analysing crop canopy temperature change by using UAV thermal infrared technology.

关键词： Canopy temperature Radiative transfer model coverage degree Temperature vegetation drought index UAV thermal infrared image

来源：评论

学校读者我要写书评

暂无评论

The Node Deployment of Intelligent Sensor Networks Based on the Spatial Difference of Farmland Soil

引用

SENSORS 2015年第11期15卷 28314-28339页

作者： Liu, Naisen Cao, Weixing Zhu, Yan Zhang, Jingchao Pang, Fangrong Ni, Jun Nanjing Agr Univ Natl Engn & Technol Ctr Agr Jiangsu Key Lab Informat Agr Collaborat Innovat Ctr Modern Crop Prod Nanjing 210095 Jiangsu Peoples R China Jiangsu Collaborat Innovat Ctr Technol & Applicat Nanjing 210095 Jiangsu Peoples R China Huaiyin Normal Univ Jiangsu Key Lab Ecoagr Biotechnol Hongze Lake Collaborat Innovat Ctr Reg Modern Agr & Environm Huaian 223300 Peoples R China Natl Minist Agr Nanjing Inst Agr Mech Nanjing 210014 Jiangsu Peoples R China

Considering that agricultural production is characterized by vast areas, scattered fields and long crop growth cycles, intelligent wireless sensor networks (WSNs) are suitable for monitoring crop growth information. Cost and coverage are the most key indexes for WSN applications. The differences in crop conditions are influenced by the spatial distribution of soil nutrients. If the nutrients are distributed evenly, the crop conditions are expected to be approximately uniform with little difference;on the contrary, there will be great differences in crop conditions. In accordance with the differences in the spatial distribution of soil information in farmland, fuzzy c-means clustering was applied to divide the farmland into several areas, where the soil fertility of each area is nearly uniform. Then the crop growth information in the area could be monitored with complete coverage by deploying a sensor node there, which could greatly decrease the deployed sensor nodes. Moreover, in order to accurately judge the optimal cluster number of fuzzy c-means clustering, a discriminant function for Normalized Intra-Cluster Coefficient of Variation (NICCV) was established. The sensitivity analysis indicates that NICCV is insensitive to the fuzzy weighting exponent, but it shows a strong sensitivity to the number of clusters.

关键词： intelligent sensor network deployment farmland soil differences coverage degree cost fuzzy c-means clustering normalized intra-cluster coefficient of variation

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：