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IQABC-Based Hybrid Deployment Algorithm for Mobile Robotic Agents Providing Network Coverage

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Tsinghua Science and Technology 2024年第2期29卷 589-604页

作者： Shuang xu Xiaojie Liu Dengao Li Jumin Zhao College of Computer Science and Technology(College of Data Science) Taiyuan University of TechnologyTaiyuan 030024China Pengcheng Laboratory Shenzhen 518055China College of Information and Computer Taiyuan University of TechnologyTaiyuan 030024China

Working as aerial base stations,mobile robotic agents can be formed as a wireless robotic network to provide network services for on-ground mobile devices in a target ***,a challenging issue is how to deploy these mobile robotic agents to provide network services with good quality for more users,while considering the mobility of on-ground *** this paper,to solve this issue,we decouple the coverage problem into the vertical dimension and the horizontal dimension without any loss of optimization and introduce the network coverage model with maximum coverage ***,we propose a hybrid deployment algorithm based on the improved quick artificial bee *** algorithm is composed of a centralized deployment algorithm and a distributed *** proposed deployment algorithm deploy a given number of mobile robotic agents to provide network services for the on-ground devices that are independent and identically *** results have demonstrated that the proposed algorithm deploys agents appropriately to cover more ground area and provide better coverage uniformity.

关键词： wireless robotic networks network coverage deployment algorithm improved quick artificial bee colony

Energy conversion characteristics of reciprocating piston quasi- isothermal compression systems using water sprays

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Science China(Technological Sciences) 2018年第2期61卷 285-298页

作者： jia guanwei cai maolin xu weiqing shi yan school of automation science and electrical engineering beihang universityBeijing 100191China pneumatic and thermodynamic energy storage and supply beijing key laboratory beihang universityBeijing 100191China

Air compressors are vital and have numerous industrial applications. Approximately 8% of the annual operating electricity consumption in industrial countries is constituted by due to the use of air compressors. Because the poor heat transfer to the environment in the rapid compression process, the compression is non-isothermal, the efficiency of compressors is restricted. To improve their efficiency and achieve isothermal compression, this study proposes energy conversion reciprocating piston quasiisothermal compression using a water spray. First, a mathematical model of a reciprocating piston compressor with water sprays was established. Through experimental investigation and simulations, the mathematical model was validated. The energy conversion characteristics of the reciprocating piston compressor were then studied. To reduce compression power and enhance compression efficiency, it was first discovered that the critical parameters were the input pressure of the driving chamber, water spray mass, and compression volume ratio, which were then evaluated thoroughly. The higher the inlet pressure of the driving chamber, the faster the air compression velocity. Additionally, the compression efficiency was elevated as the water spray mass was gradually increased for a given compression volume ratio. When the compression volume ratio was increased from 2 to 3,the compression power increased from 172.7 J/stroke to 294.2 J/stroke and the compression efficiency was enhanced from 37.3%(adiabatic) to 80.6%. This research and its performance analysis can be referred to during the parameter design optimisation of reciprocating piston quasi-isothermal compression systems using water sprays.

关键词： water spray cooling quasi-isothermal compression compression power compression efficiency

Label distribution for multimodal machine learning

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Frontiers of Computer Science 2022年第1期16卷 33-43页

作者： Yi REN Ning xu Miaogen LING Xin GENG Department of Computer Science and Engineering Southeast UniversityNanjing211189China

Multimodal machine learning(MML)aims to understand the world from multiple related *** has attracted much attention as multimodal data has become increasingly available in real-world *** is shown that MML can perform better than single-modal machine learning,since multi-modalities containing more information which could complement each ***,it is a key challenge to fuse the multi-modalities in *** from previous work,we further consider the side-information,which reflects the situation and influences the fusion of *** recover multimodal label distribution(MLD)by leveraging the side-information,representing the degree to which each modality contributes to describing the ***,a novel framework named multimodal label distribution learning(MLDL)is proposed to recover the MLD,and fuse the multimodalities with its guidance to learn an in-depth understanding of the jointly feature ***,two versions of MLDL are proposed to deal with the sequential *** on multimodal sentiment analysis and disease prediction show that the proposed approaches perform favorably against state-of-the-art methods.

关键词： multimodal machine learning label distribution learning sentiment analysis disease prediction

Effects of Nanosilica on Crystallization and Thermal Ageing Behaviors of Polyethylene Terephthalate

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Chinese Journal of Polymer Science 2015年第5期33卷 697-708页

作者： Ying-jie xu 宋义虎 Qiang Zheng MOE Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and EngineeringZhejiang University

The effects of nanosilica（SiO2） on crystallization and thermal aging behaviors of polyethylene terephthalate（PET） have been studied using differential scanning calorimetry（DSC） and polarized optical microscopy（POM）, viscometry, tensile testing and scanning electron microscopy（SEM）. For non-isothermal and isothermal crystallizations, the crystallization rate of PET increases considerably with increasing content of SiO2 providing a large number of nucleation sites, but the relative crystallinity of the nanocomposites has little differences with that of neat PET. According to POM observation, the nucleation of PET becomes faster and the nucleation density increases significantly with increasing SiO2 content. For PET and its nanocomposites thermally aged at 190 ℃, the results of intrinsic viscosity, carboxyl content and tensile test show that the degradation rate of PET is reduced with the addition of a small content of SiO2, but the degradation rate increases with further addition of SiO2, owing to the dual effect of SiO2 on PET degradation.

关键词： Polyethylene terephthalate Nanosilica Crystallization Thermal ageing

CHEMICAL BEHAVIOR OF CERIUM ELEMENT IN ROCK WEATHERING SYSTEM

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中国有色金属学会会刊：英文版 1999年第1期9卷 160-166页

作者： Chi, Ru'an Zhu, Guocai Zhang, Ping xu, Yinghui Tsinghua Univ Beijing China

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１ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｅｌｅｃｔｒｏｎｉｃｓｔｒｕｃｔｕｒｅｏｆｇｒｏｕｎｄｓｔａｔｅａｔｏｍｃｅｒｉｕｍｉｓＸｅ４ｆ１５ｄ１６ｓ２，ａｎｄｔｈｅｅｌｅｃｔｒｏｎｉｃｓｔｒｕｃｔｕｒｅｏｆｔｒｉｖａｌｅｎｔｏｘｉｄｉｚｉｎｇｓｔａｔｅｉｓＸ...

关键词： cerium rare earth ore weathering system chemical behavior

Far-Field Pattern Tolerance Analysis of Reflector Antenna with Random or System Error Based on Interval Arithmetic

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Chinese Journal of Electronics 2018年第3期27卷 641-647页

作者： LI Peng LI Na xu Wanye WANG Wei Key Laboratory of Electronic Equipment Structure Design Ministry of Education Xidian University

A novel analytic approach for the research of effect on electromagnetic performance of reflector antennas with deformation, including random processing error and system error caused by external loads(such as wind,gravity, and solar radiation), in panels of the reflector surface is proposed. The deformations are modeled as error intervals, and their impact on the electromagnetic performance, including radiation power pattern and some main electromagnetic characteristics(such as side lobe level,peak power, and half-power beamwidth), are efficiently estimated by Interval analysis(IA). The closed-form equations indicate the relationship between the error interval and the bounds(upper and lower bounds) of the radiated power pattern interval by exploiting the rules of interval arithmetic. Two kinds of surface errors(random and system error) and two shapes of deformation area(bump-like and sector) are taken into account in the numerical examples to assess the validation and effectiveness of the proposed approach. The results of the examples show that the proposed IA-based approach has great capability and effectiveness regarding the traditional statistical method(such as Monte-Carlo method).

关键词： Reflector antenna Interval analysis Random error System error Power pattern

Nondestructive Testing and Characterization of Residual Stress Field Using an Ultrasonic Method

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Chinese Journal of Mechanical Engineering 2016年第2期29卷 365-371页

作者： SONG Wentao xu Chunguang PAN Qinxue SONG Jianfeng School of Mechanical Engineering Beijing Institute of Technology School of Mechanical Engineering Shijiazhuang Tiedao University

To address the difficulty in testing and calibrating the stress gradient in the depth direction of mechanical components, a new technology of nondestructive testing and characterization of the residual stress gradient field by ultrasonic method is proposed based on acoustoelasticity theory. By carrying out theoretical analysis, the sensitivity coefficients of different types of ultrasonic are obtained by taking the low carbon steel（12%C） as a research object. By fixing the interval distance between sending and receiving transducers, the mathematical expressions of the change of stress and the variation of time are established. To design one sending-one receiving and oblique incidence ultrasonic detection probes, according to Snell law, the critically refracted longitudinal wave（LCR wave） is excited at a certain depth of the fixed distance of the tested components. Then, the relationship between the depth of LCR wave detection and the center frequency of the probe in Q235 steel is obtained through experimental study. To detect the stress gradient in the depth direction, a stress gradient LCR wave detection model is established, through which the stress gradient formula is derived by the relationship between center frequency and detecting depth. A C-shaped stress specimen of Q235 steel is designed to conduct stress loading tests, and the stress is measured with the five group probes at different center frequencies. The accuracy of ultrasonic testing is verified by X-ray stress analyzer. The stress value of each specific depth is calculated using the stress gradient formula. Accordingly, the ultrasonic characterization of residual stress field is realized. Characterization results show that the stress gradient distribution is consistent with the simulation in ANSYS. The new technology can be widely applied in the detection of the residual stress gradient field caused by mechanical processing, such as welding and shot peening.

关键词： ultrasonic nondestructive testing acoustoelasticity theory residual stress field stress gradient ultrasonic characterization

Construction and Count of 1-Resilient Rotation Symmetric Boolean Functions on 4p Variables

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Chinese Journal of Electronics 2017年第6期26卷 1276-1283页

作者： PANG Shanqi xu Wenju DU Jiao WANG Ying College of Mathematics and Information Science Henan Normal University

This paper studies the properties of orbit matrix and gives a formula to compute the number of these orbit matrices on 4p variables, where p is an odd prime. It has been demonstrated that the construction of 1-resilient Rotation symmetric Boolean functions(RSBFs) on 4p variables is equivalent to solving an equation system. By the proposed method, all 1-resilient RSBFs on 12 variables can be constructed. We present a counting formula for the total number of all 1-resilient RSBFs on 4p variables. As application of our method, some 1-resilient RSBFs on 12 variables are presented.

关键词： Cryptography Rotation symmetric Boolean functions Orbit matrix Resilient functions

Brief History of xu-style Garden in the Middle Ancient Times of China

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Journal of Landscape Research 2021年第1期13卷 15-18页

作者： xu Jianguo Research Institute of xu-Style Landscape Architecture XuzhouJiangsu 221000China

According to ancient books and documents,this paper collected and sorted out the people and things related to xu-style gardens in the middle ancient period of Chinese history,during the 400 years from the division of“Three Kingdoms”to the unifi cation of Sui *** the frequent war chaos,gardening constructions in xuzhou were hardly seen in this period,but the gardening fruits of xu-style garden had spread all over the country with a large number of xu people moving *** inheriting the splendid and rough style of Qin and Han Dynasties,xu-style garden attached more importance to“spectacular”,summarized and put forward the ideas of“master nature”and“artistic conception”,and raised the gardening technique to a theoretical height,thus pioneered the idea of“master nature”in Chinese classical gardens.

关键词： xu-style garden Middle ancient times of China Gardening events