检索结果-南通市图书馆

Distributed cooperative deployment strategy in multi-UAVs assisted heterogeneous networks

在线全文

学校读者我要写书评

暂无评论

The Journal of China Universities of Posts and Telecommunications 2021年第3期28卷 11-19页

作者： Zhang Yi Zhang Heli ji Hong Li xi School of Information and Communication Engineering Beijing University of Posts and TelecommunicationsBeijing 100876China

Unmanned aerial vehicle base stations(UAV-BSs)can provide a fast network deployment scheme for heterogeneous ***,unmanned aerial vehicle(UAV)has limited capability and cannot assist the base station(BS)*** ability of a UAV to assist the BSs is limited,and the cluster deployment relies on the leading *** dispersive deployment of multiple UAVs(multi-UAVs)need a macro base station(MBS)to determine their positions to prevent collisions or ***,a distributed cooperative deployment scheme is proposed for UAVs to solve this *** scheme can increase the ability of UAVs to assist users and reduce the pressure on BSs to deploy ***,the randomly distributed users are *** the placement problem was modeled as a circle expansion problem and a pre-clustering radius expansion algorithm was *** the constraint of users'data rates,it provides services for more ***,the proposed algorithm was compared with the density-aware placement *** simulation results show that the proposed algorithm can provide services for more users and improve the coverage rate of users while ensuring the data rates.

关键词： unmanned aerial vehicle base stations(UAV-BSs) distributed cooperative pre-clustering radius expansion algorithm unmanned aerial vehicles(UAVs)deployment

同方期刊数据库

Resource allocation and hybrid prediction scheme for low-latency visual feedbacks to support tactile Internet multimodal perceptions

在线全文

学校读者我要写书评

暂无评论

The Journal of China Universities of Posts and Telecommunications 2021年第4期28卷 13-28页

作者： Kang Mancong Li xi ji Hong Zhang Heli School of Telecommunication Engineering Beijing University of Posts and TelecommunicationsBeijing 100876China

Predicting user states in future and rendering visual feedbacks accordingly can effectively reduce the visual experienced delay in the tactile Internet(TI). However, most works omit the fact that different parts in an image may have distinct prediction requirements, based on which different prediction models can be used in the predicting process, and then it can further improve predicting quality especially under resources-limited environment. In this paper, a hybrid prediction scheme is proposed for the visual feedbacks in a typical TI scenario with mixed visuo-haptic interactions, in which haptic traffic needs sufficient wireless resources to meet its stringent communication requirement, leaving less radio resources for the visual feedback. First, the minimum required number of radio resources for haptic traffic is derived based on the haptic communication requirements, and wireless resources are allocated to the haptic and visual traffics afterwards. Then, a grouping strategy is designed based on the deep neural network(DNN) to allocate different parts from an image feedback into two groups to use different prediction models, which jointly considers the prediction deviation thresholds, latency and reliability requirements, and the bit sizes of different image parts. Simulations show that, the hybrid prediction scheme can further reduce the visual experienced delay under haptic traffic requirements compared with existing strategies.

关键词： tactile Internet ultra-reliable and low-latency communications enhanced mobile broadband visuo-haptic feedbacks layered rendering

Quark stars with strong magnetic fields: considering different magnetic field geometries

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2017年第10期17卷 27-32页

作者： Wei Wei xi-Wei Liu xiao-ping Zheng College of Science Huazhong Agricultural University College of Physical Science and Technology Central China Normal University

We calculate the mass-radius relationship of quark stars with the magnetized density- dependent quark mass model in this work, considering two magnetic field geometries： a statistically isotropic, tangled field and a force-free configuration. In both cases, magnetic field production decreases in the case of maximum quark star mass. Furthermore, a tangled, isotropic magnetic field has a relatively smaller impact on the mass and radius, compared to the force-free configuration, which implies that the geometry of the interior magnetic field is at least as important as the field strength itself when the influ- ence of the strong magnetic field on the mass and radius is assessed.

关键词： stars: neutron -- equation of state -- magnetic fields

A Multi-UCAV cooperative occupation method based on weapon engagement zones for beyond-visual-range air combat

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2022年第6期18卷 1006-1022页

作者： Wei-hua Li jing-ping Shi Yun-yan Wu Yue-ping Wang Yong-xi Lyu School of Automation Northwestern Polytechnical UniversityXi'an710129China Shaanxi Province Key Laboratory of Flight Control and Simulation Technology Xi'an710129China Science and Technology on Aircraft Control Laboratory FACRIXi'an710065China

Recent advances in on-board radar and missile capabilities,combined with individual payload limitations,have led to increased interest in the use of unmanned combat aerial vehicles(UCAVs)for cooperative occupation during beyond-visual-range(BVR)air ***,prior research on occupational decision-making in BVR air combat has mostly been limited to one-on-one *** such,this study presents a practical cooperative occupation decision-making methodology for use with multiple *** weapon engagement zone(WEZ)and combat geometry were first used to develop an advantage function for situational assessment of one-on-one *** encircling advantage function was then designed to represent the cooperation of UCAVs,thereby establishing a cooperative occupation *** corresponding objective function was derived from the one-on-one engagement advantage function and the encircling advantage *** resulting model exhibited similarities to a mixed-integer nonlinear programming(MINLP)*** such,an improved discrete particle swarm optimization(DPSO)algorithm was used to identify a *** occupation process was then converted into a formation switching task as part of the cooperative occupation model.A series of simulations were conducted to verify occupational solutions in varying situations,including two-on-two *** results showed these solutions varied with initial conditions and weighting *** occupation process,based on formation switching,effectively demonstrates the viability of the proposed *** cooperative occupation results could provide a theoretical framework for subsequent research in cooperative BVR air combat.

关键词： Unmanned combat aerial vehicle Cooperative occupation Beyond-visual-range air combat Weapon engagement zone Discrete particle swarm optimization Formation switching

A TRUST REGION-TYPE METHOD FOR SOLVINGMONOTONE VARIATIONAL INEQUALITY

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2000年第1期18卷 13-24页

作者： xi-ming Liang Cheng-xian Xu ji-xin Qian Institute of Industrial Process Control National Lab of Industrial Control TechnologyZhejiang UniversityHangzhou 310027China School of Science Xi’an Jiaotong UniversityXi’an 710049China

Presents a study which proposed to introduce a trust region-type modification of Newton method for the monotone inequality problem using merit function. Concepts of monotone mapping; Proof of convergence of algorithm ... 详细信息

关键词： variational inequality problem trust region method global convergence quadratic convergence

Resource allocation for load balancing and fairness improvement in relay-assisted OFDMA cellular

在线全文

学校读者我要写书评

暂无评论

High Technology Letters 2011年第4期17卷 377-382页

作者： Zhang Hailong ji Hong Li xi Key Lab of Universal Wireless Communications Ministry of EducationBeijing University of Posts and Telecommunications Beijing 100876 P.R.China

A resource allocation scheme with the considerations of user fairness and load balancing is proposed in orthogonal frequency division multiple access （OFDMA）-based relay networks. The optimal resource allocation scheme is formulated mathematically to maximize the minimum achievable rate among all user equipments （UEs） for fairnegs improvement. The optimal problem has been proved to be N-P-hard and it is prohibitive to find the optimal solution for its computational complexity. Accordingly, this paper proposes a suboptimal scheme which considers not only user fairness but also load balancing among base stations （BS） and relay stations （RSs） during resource allocation procedure. The suboptimal scheme takes the traffic load of access nodes （BS and RSs） into consideration to balance the system traffic load, which would prevent them from overloading and throughput degradation. Simulation results show that the suboptimal scheme performs similarly to the optimal solution and can enhance the system fairness and load balancing performance significantly compared with the traditional schemes.

关键词： radio resource allocation relay fairness load balancing orthogonal frequency division multiple access (OFDMA)

Regional study on investment for transmission infrastructure in China based on the State Grid data

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Earth Science 2017年第1期11卷 162-183页

作者： Wendong WEI Xudong WU xiaofang WU Qiangmin xi xi ji Guoping LI College of Government Peking University Beijing 100871 China College of Engineering Peking University Beijing 100871 China School of Economics Nankai University Tianjin 300071 China School of Economics Peking University Beijing 100871 China

Transmission infrastructure is an integral component of safeguarding the stability of electricity delivery. However, existing studies of transmission infra- structure mostly rely on a simple review of the network, while the analysis of investments remains rudimentary. This study conducted the first regionally focused analysis of investments in transmission infrastructure in China to help optimize its structure and reduce investment costs. Using State Grid data, the investment costs, under various voltages, for transmission lines and transformer substa- tions are calculated. By analyzing the regional profile of cumulative investment in transmission infrastructure, we assess correlations between investment, population, and economic development across the regions. The recent development of ultra-high-voltage transmission networks will provide policy-makers new options for policy development.

关键词： regional study energy geography investment analysis transmission lines transformer substation

The neuroscience of pain,addiction,and anesthesia

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Zoological Research 2024年第3期45卷 709-710页

作者： ji Hu ping Zheng School of Life Science and Technology ShanghaiTech UniversityShanghai 201210China State Key Laboratory of Medical Neurobiology Institutes of Brain ScienceMOE Frontier Center for Brain ScienceDepartment of Neurology of Zhongshan HospitalFudan UniversityShanghai 200032China

Researchers and clinicians have long been interested in the mechanisms of pain,anesthesia,and *** International Association for the Study of Pain(IASP)defines pain as an unpleasant sensory and emotional experience associated with,or resembling that associated with,actual or potential tissue damage(Raja et al.,2020).Drug addiction refers to a condition of reliance that develops from regular drug consumption,which may lead to withdrawal symptoms when use is *** involves the complete loss of consciousness induced by an inhaled or intravenous anesthetic(Tosello et al.,2022).In this special collection,Zoological Research presents research findings focused on pain,addiction,and anesthesia.

关键词： anesthesia damage

Distributed Edge Cooperation and Data Collection for Digital Twins of Wide-Areas

在线全文

学校读者我要写书评

暂无评论

China Communications 2023年第8期20卷 177-197页

作者： Mancong Kang xi Li Hong ji Heli Zhang Key Laboratory of Universal Wireless Communications Beijing University of Posts and TelecommunicationsBeijing 100876China

Digital twins for wide-areas(DT-WA)can model and predict the physical world with high fidelity by incorporating an artificial intelligence(AI)***,the AI model requires an energy-consuming updating process to keep pace with the dynamic environment,where studies are still in *** reduce the updating energy,this paper proposes a distributed edge cooperation and data collection *** AI model is partitioned into multiple sub-models deployed on different edge servers(ESs)co-located with access points across wide-area,to update distributively using local sensor *** reduce the updating energy,ESs can choose to become either updating helpers or recipients of their neighboring ESs,based on sensor quantities and basic updating *** would share their updated sub-model parameters with neighboring recipients,so as to reduce the latter updating *** minimize system energy under updating convergency and latency constraints,we further propose an algorithm to let ESs distributively optimize their cooperation identities,collect sensor data,and allocate wireless and computing *** comprises several constraint-release approaches,where two child optimization problems are solved,and designs a largescale multi-agent deep reinforcement learning *** shows that the proposed scheme can efficiently reduce updating energy compared with the baselines.

关键词： digital twin smart city multi-agent deep reinforcement learning resource allocation