期刊文献+
共找到2,276篇文章
< 1 2 114 >
每页显示 20 50 100
DNBP-CCA:A Novel Approach to Enhancing Heterogeneous Data Traffic and Reliable Data Transmission for Body Area Network
1
作者 Abdulwadood Alawadhi Mohd.Hasbullah Omar +3 位作者 Abdullah Almogahed Noradila Nordin Salman A.Alqahtani Atif M.Alamri 《Computers, Materials & Continua》 SCIE EI 2024年第5期2851-2878,共28页
The increased adoption of Internet of Medical Things (IoMT) technologies has resulted in the widespread use ofBody Area Networks (BANs) in medical and non-medical domains. However, the performance of IEEE 802.15.4-bas... The increased adoption of Internet of Medical Things (IoMT) technologies has resulted in the widespread use ofBody Area Networks (BANs) in medical and non-medical domains. However, the performance of IEEE 802.15.4-based BANs is impacted by challenges related to heterogeneous data traffic requirements among nodes, includingcontention during finite backoff periods, association delays, and traffic channel access through clear channelassessment (CCA) algorithms. These challenges lead to increased packet collisions, queuing delays, retransmissions,and the neglect of critical traffic, thereby hindering performance indicators such as throughput, packet deliveryratio, packet drop rate, and packet delay. Therefore, we propose Dynamic Next Backoff Period and Clear ChannelAssessment (DNBP-CCA) schemes to address these issues. The DNBP-CCA schemes leverage a combination ofthe Dynamic Next Backoff Period (DNBP) scheme and the Dynamic Next Clear Channel Assessment (DNCCA)scheme. The DNBP scheme employs a fuzzy Takagi, Sugeno, and Kang (TSK) model’s inference system toquantitatively analyze backoff exponent, channel clearance, collision ratio, and data rate as input parameters. Onthe other hand, the DNCCA scheme dynamically adapts the CCA process based on requested data transmission tothe coordinator, considering input parameters such as buffer status ratio and acknowledgement ratio. As a result,simulations demonstrate that our proposed schemes are better than some existing representative approaches andenhance data transmission, reduce node collisions, improve average throughput, and packet delivery ratio, anddecrease average packet drop rate and packet delay. 展开更多
关键词 Internet of Medical Things body area networks backoff period tsk fuzzy model clear channel assessment media access control
下载PDF
ASYMMETRIC VORTICES FLOW OVER SLENDER BODY AND ITS ACTIVE CONTROL AT HIGH ANGLE OF ATTACK 被引量:16
2
作者 邓学蓥 王延奎 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2004年第6期567-579,共13页
The studies of asymmetric vortices flow over slender body and its active control at high angles of attack have significant importance for both academic field and engineering area.This paper attempts to provide an upda... The studies of asymmetric vortices flow over slender body and its active control at high angles of attack have significant importance for both academic field and engineering area.This paper attempts to provide an update state of art to the investigations on the fields of forebody asymmetric vortices.This review emphasizes the correlation between micro-perturbation on the model nose and its response and evolution behaviors of the asymmetric vortices.The critical issues are discussed, which include the formation and evolution mechanism of asymmetric multi-vortices;main behaviors of asymmetric vortices flow including its deterministic feature and vortices flow structure;the evolution and development of asymmetric vortices under the perturbation on the model nose;forebody vortex active control especially discussed micro-perturbation active control concept and technique in more detail.However present understanding in this area is still very limited and this paper tries to identify the key unknown problems in the concluding remarks. 展开更多
关键词 asymmetric vortex flow control high angle of attack aerodynamics slender body
下载PDF
Optimal control of attitude for coupled-rigid-body spacecraft via Chebyshev-Gauss pseudospectral method 被引量:3
3
作者 Xinsheng GE Zhonggui YI Liqun CHEN 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2017年第9期1257-1272,共16页
The attitude optimal control problem (OCP) of a two-rigid-body space- craft with two rigid bodies coupled by a ball-in-socket joint is considered. Based on conservation of angular momentum of the system without the ... The attitude optimal control problem (OCP) of a two-rigid-body space- craft with two rigid bodies coupled by a ball-in-socket joint is considered. Based on conservation of angular momentum of the system without the external torque, a dynamic equation of three-dimensional attitude motion of the system is formulated. The attitude motion planning problem of the coupled-rigid-body spacecraft can be converted to a dis- crete nonlinear programming (NLP) problem using the Chebyshev-Gauss pseudospectral method (CGPM). Solutions of the NLP problem can be obtained using the sequential quadratic programming (SQP) algorithm. Since the collocation points of the CGPM are Chebyshev-Gauss (CG) points, the integration of cost function can be approximated by the Clenshaw-Curtis quadrature, and the corresponding quadrature weights can be calculated efficiently using the fast Fourier transform (FFT). To improve computational efficiency and numerical stability, the barycentric Lagrange interpolation is presented to substitute for the classic Lagrange interpolation in the approximation of state and con- trol variables. Furthermore, numerical float errors of the state differential matrix and barycentric weights can be alleviated using trigonometric identity especially when the number of CG points is large. A simple yet efficient method is used to avoid sensitivity to the initial values for the SQP algorithm using a layered optimization strategy from a feasible solution to an optimal solution. Effectiveness of the proposed algorithm is perfect for attitude motion planning of a two-rigid-body spacecraft coupled by a ball-in-socket joint through numerical simulation. 展开更多
关键词 coupled rigid body SPACECRAFT optimal control pseudospectral method(PM) Chebyshev-Gauss (CG) point
下载PDF
INVESTIGATION OF ACTIVE CONTROL FOR DYNAMIC STABILITY OF HELICOPTER ROTOR-BODY COUPLING 被引量:1
4
作者 Ling Aimin(Chinese Helicopter Research and Design Institute,Jindezhn, Jiangxi, China, 333001) 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 1996年第4期269-272,共4页
A study is conducted on the feasibility of helicopter ground and air resonanceby using actively controlled tabs mounted at the trailing edge of an aerofoil. A method isdeveloped to obtain the optimal feedback control ... A study is conducted on the feasibility of helicopter ground and air resonanceby using actively controlled tabs mounted at the trailing edge of an aerofoil. A method isdeveloped to obtain the optimal feedback control law through constructing a referencemodel according to requirements of stability levels in the modal space. The effects of rotorspeed and length and location of tabs on the control law are analyzed, and it is found possible that a controller can be designed into constant feedback gain against rotor speed andto feed back only to the dominant system states to eliminate the unstable range of rotorspeed. 展开更多
关键词 tabs (control surfaces) helicopters rotor body interactions COUPLING dynamic stability active control
下载PDF
STABILITY ANALYSES ON DYNAMIC CONTROL FOR A MOVING BODY LEVITATED MAGNETICALLY OVER ELASTIC GUIDEWAYS 被引量:1
5
作者 Zhou Youhe Gao Yuanwen Zheng Xiaojing 《Acta Mechanica Solida Sinica》 SCIE EI 1999年第3期239-247,共9页
Based on the Floquet theory on ordinary differential equationswith periodically variable coefficients and the bifurcation approachto nonlinear equations, a numerical approach to determining thestability region of cont... Based on the Floquet theory on ordinary differential equationswith periodically variable coefficients and the bifurcation approachto nonlinear equations, a numerical approach to determining thestability region of control parameters is established for a dynamiccontrol system composed of a moving body levitated magnetically overflexible guideways. The system is nonlinearly coupled among theelastic deformation of guideways, disturbance the levitation positionof the body and electromagnet- ic control forces. 展开更多
关键词 elastic guideways magnetically levitated body dynamic control
下载PDF
Pollution control of urban black-odor water bodies 被引量:4
6
作者 FAN Kai-qing JIA Jun +1 位作者 SUN Ping-li LIANG Hui-min 《Ecological Economy》 2017年第4期344-350,共7页
On the basis of on-the-spot investigation, the causes of urban black-odor water bodies and the problems existing in the treatment are analyzed, and the control techniques and management countermeasures for black-odor ... On the basis of on-the-spot investigation, the causes of urban black-odor water bodies and the problems existing in the treatment are analyzed, and the control techniques and management countermeasures for black-odor water bodies were put forward. The countermeasures include: treating from both the roots and the symptoms and combining multiple technologies; comprehensively managing and improve the monitoring systems; coordinating functions and implementing long-term management; opening information and innovating supervision platform; coordinating advance and promoting the construction of sponge city; diversified financing to form the market-oriented model of water pollution control. 展开更多
关键词 black-odor water bodies pollution control control techniques
下载PDF
Optimal design method for force in vibration control of multi-body system with quick startup and brake 被引量:3
7
作者 唐华平 彭娅清 《Journal of Central South University of Technology》 EI 2005年第4期459-464,共6页
A kind of active vibration control method was presented through optimal design of driving load of multi-body system with quick startup and brake. Dynamical equation of multi-body system with quick startup and brake wa... A kind of active vibration control method was presented through optimal design of driving load of multi-body system with quick startup and brake. Dynamical equation of multi-body system with quick startup and brake was built, and mathematical model of representing vibration control was also set up according to the moving process from startup to brake. Then optimization vibration control model of system driving load was founded by applying theory of optimization control, which takes rigid body moving variable of braking moment as the known condition, and vibration control equation of multi-body system with quick startup and brake was converted into boundary value problem of differential equation. The transient control algorithm of vibration was put forward, which is the analysis basis for the further research. Theoretical analysis and calculation of numerical examples show that the optimal design method for the multi-body system driving load can decrease the vibration of system with duplication. 展开更多
关键词 振动控制 多体系统 主动控制 机械装置 机械振动
下载PDF
Quantitative analysis of geological ore-controlling factors and stereoscopic quantitative prediction of concealed ore bodies 被引量:4
8
作者 毛先成 邹艳红 +2 位作者 卢晓琴 吴湘滨 戴塔根 《Journal of Central South University》 SCIE EI CAS 2009年第6期987-993,共7页
To address the issues for assessing and prospecting the replaceable resource of crisis mines,a geological ore-controlling field model and a mineralization distribution field model were proposed from the viewpoint of f... To address the issues for assessing and prospecting the replaceable resource of crisis mines,a geological ore-controlling field model and a mineralization distribution field model were proposed from the viewpoint of field analysis. By dint of solving the field models through transferring the continuous models into the discrete ones,the relationship between the geological ore-controlling effect field and the mineralization distribution field was analyzed,and the quantitative and located parameters were extracted for describing the geological factors controlling mineralization enrichment. The method was applied to the 3-dimensional localization and quantitative prediction for concealed ore bodies in the depths and margins of the Dachang mine in Guangxi,China,and the 3-dimensional distribution models of mineralization indexes and ore-controlling factors such as magmatic rocks,strata,faults,lithology and folds were built. With the methods of statistical analysis and the non-linear programming,the quantitative index set of the geological ore-controlling factors was obtained. In addition,the stereoscopic located and quantitative prediction models were set up by exploring the relationship between the mineralization indexes and the geological ore-controlling factors. So far,some concealed ore bodies with the resource volume of a medium-sized mineral deposit are found in the deep parts of the Dachang Mine by means of the deep prospecting drills following the prediction results,from which the effectiveness of the predication models and results is proved. 展开更多
关键词 定量预测 隐伏矿体 控矿因素 定量分析 立体 地质
下载PDF
Cavitation Passive Control on Immersed Bodies 被引量:4
9
作者 Khodayar Javadi Mohammad Mortezazadeh Dorostkar Ali Katal 《Journal of Marine Science and Application》 CSCD 2017年第1期33-41,共9页
这份报纸介绍通过称为人工的成穴水泡生成器(ACG ) 的一个被动成穴控制器在一只水翼船附近控制成穴的一个新想法。周期也就是,在沉浸的身体附近处理水泡的生长和内爆,是为说的身体的破坏和侵蚀的主要原因。这份报纸试图创造成穴水泡... 这份报纸介绍通过称为人工的成穴水泡生成器(ACG ) 的一个被动成穴控制器在一只水翼船附近控制成穴的一个新想法。周期也就是,在沉浸的身体附近处理水泡的生长和内爆,是为说的身体的破坏和侵蚀的主要原因。这份报纸试图创造成穴水泡在到达一种不变的状况并且阻止周期的过程的出现的一个条件。为这个目的,特别地, ACG 被放在沉浸的身体的表面上一只 2D 水翼船的吸表面。模拟基于与联系的一个简单算法与一个含蓄的有限体积计划被执行多相并且成穴模型。与狂暴的粘性的修正装备的修改的 k- RNG 骚乱模型被使用克服骚乱闭合问题。在与一个低压的再通行区域在 ACG 后面并且人工地被生产的 ACG 表演装备的水翼船上的水流动的数字模拟产生静止成穴水泡。这 ACG 的地点,形状,和尺寸是在创造合适的控制的关键参数。结果证明成穴水泡与设计得好的 ACG 被控制很好。 展开更多
关键词 空化模型 无源控制 气泡发生器 RNG湍流模型 浸没 湍流粘性系数 循环过程 ACG
下载PDF
The present status and prospects in the research of orbital dynamics and control near small celestial bodies
10
作者 Pingyuan Cui Dong Qiao 《Theoretical & Applied Mechanics Letters》 CAS 2014年第1期1-14,共14页
Small celestial body exploration is of great significance to deep space activities. The dynamics and control of orbits around small celestial bodies is of top priority in the exploration research. It includes the mode... Small celestial body exploration is of great significance to deep space activities. The dynamics and control of orbits around small celestial bodies is of top priority in the exploration research. It includes the modeling of dynamics environment and the orbital dynamics mechanism. This paper introduced state-ofthe-art researches, major challenges, and future trends in this field. Three topics are mainly discussed: the gravitational field modeling of irregular-shaped small celestial bodies, natural orbital dynamics and control, and controlled orbital dynamics. Finally, constructive suggestions are made for China’s future space exploration missions. 展开更多
关键词 small celestial body exploration dynamics and control gravitational field of irregular-shaped body natural orbital dynamics controlled orbital dynamics
下载PDF
Body temperature control in fever modeling after preliminary injection of glutamate receptors ligands into the solitary tract nucleus
11
作者 Stanislav V. Koulchitsky Svetlana G. Pashkevich +2 位作者 Nastassia M. Navasiolava Marc-Antoine Custaud Vladimir A. Kulchitsky 《Advances in Bioscience and Biotechnology》 2013年第4期557-562,共6页
Deep body temperature of 57 male Wistar rats was measured in response to systemic (i.v. or i.p.) injection of Escherichia coli lipopolysaccharide (LPS). Animals were preliminarily (4 weeks before the experiment) treat... Deep body temperature of 57 male Wistar rats was measured in response to systemic (i.v. or i.p.) injection of Escherichia coli lipopolysaccharide (LPS). Animals were preliminarily (4 weeks before the experiment) treated with microinjections of the toxic dose of glutamate receptors agonists or vehicle into solitary tract nucleus or caudal part of ventrolateral medulla. Microinjections of the glutamate receptors agonists provoked a local destruction of brain tissue, which was accompanied by the significant transformation (amplification or attenuation) of temperature response to the systemic injection of 3 μg/kg E. coli LPS. Animals treated with vehicle did not demonstrate significant changes in their response to LPS. Obtained data testify that impairment of central nervous structure involved in the regulation and maintenance of deep body temperature is accompanied by atypical development of E. coli LPS-induced fever. 展开更多
关键词 ESCHERICHIA coli ENDOTOXIN BRAINSTEM Fever control body Temperature Defense REFLEXES
下载PDF
Geological suitability of natural sponge body for the construction of sponge city——a case study of Shuanghe Lake district in Zhengzhou airport zone 被引量:1
12
作者 Yong-jun Su Hui Tang +4 位作者 Ai-min Wu Xue-ping Dai Shuang Liu Hong-wei Liu Heng Kuang 《Journal of Groundwater Science and Engineering》 2023年第2期146-157,共12页
Natural and geological environmental conditions have an important impact on the planning and construction of sponge cities.This paper analyzes geological factors that influence the usage of natural sponge bodies,takin... Natural and geological environmental conditions have an important impact on the planning and construction of sponge cities.This paper analyzes geological factors that influence the usage of natural sponge bodies,taking the Shuanghe lake district of Zhengzhou airport zone as an example.An evaluation system with seven factors has been established and the weights of these factors are determined using the analytic hierarchy process(AHP)method.Overlay analysis is then carried out on all factors using GIS to evaluate the geological suitability of the construction of the sponge city.The results show that geologically suitable area for city construction in Shuanghe lake district accounts for 12.3%,relatively suitable area accounts for 76.1%,and relatively unsuitable area accounts for 11.6%.For suitable and relatively suitable areas,we should make full use of the advantages of surface infiltration,vadose zone transportation and aquifer storage to build a sponge city infrastructure with geological engineering as the main component,supplemented by engineering measures such as surface water storage and drainage,and jointly establish a sustainable urban hydrological cycle.For less suitable areas,artificial rain and flood control works,such as roof garden,should be considered.The findings of this paper can serve as an important reference for sponge city planning and construction not only in the research area but also in other regions with similar geological conditions. 展开更多
关键词 Natural sponge bodies Low impact development Rain flood control Hierarchy analysis
下载PDF
Attitude Control of an Axi-Symmetric Rigid Body Using Two Controls without Angular Velocity Measurements Paper
13
作者 Tawfik El-Sayed Tawfik 《World Journal of Mechanics》 2013年第5期1-5,共5页
This paper considers the problem of controlling the rotational motion of an axi-symmetric rigid body using two independent control torques without angular velocity measurements. The control law which stabilizes asympt... This paper considers the problem of controlling the rotational motion of an axi-symmetric rigid body using two independent control torques without angular velocity measurements. The control law which stabilizes asymptotically this motion is obtained only in terms of the orientation parameters. Global asymptotic stability is shown by applying LaSalle invariance principal. Numerical simulation is introduced. 展开更多
关键词 ATTITUDE control RIGID body Stabilization TWO controlS
下载PDF
Geological characteristics and models of fault-foldfracture body in deep tight sandstone of the second member of Upper Triassic Xujiahe Formation in Xinchang structural belt of Sichuan Basin,SW China 被引量:1
14
作者 LIU Junlong LIU Zhongqun +8 位作者 LIU Zhenfeng LIU Yali SHEN Baojian XIAO Kaihua BI Youyi WANG Xiaowen WANG Ail FAN Lingxiao LI Jitongl 《Petroleum Exploration and Development》 SCIE 2023年第3期603-614,共12页
In the second member of the Upper Triassic Xujiahe Formation(T_(3)x_(2))in the Xinchang area,western Sichuan Basin,only a low percent of reserves has been recovered,and the geological model of gas reservoir sweet spot... In the second member of the Upper Triassic Xujiahe Formation(T_(3)x_(2))in the Xinchang area,western Sichuan Basin,only a low percent of reserves has been recovered,and the geological model of gas reservoir sweet spot remains unclear.Based on a large number of core,field outcrop,test and logging-seismic data,the T_(3)x_(2) gas reservoir in the Xinchang area is examined.The concept of fault-fold-fracture body(FFFB)is proposed,and its types are recognized.The main factors controlling fracture development are identified,and the geological models of FFFB are established.FFFB refers to faults,folds and associated fractures reservoirs.According to the characteristics and genesis,FFFBs can be divided into three types:fault-fracture body,fold-fracture body,and fault-fold body.In the hanging wall of the fault,the closer to the fault,the more developed the effective fractures;the greater the fold amplitude and the closer to the fold hinge plane,the more developed the effective fractures.Two types of geological models of FFFB are established:fault-fold fracture,and matrix storage and permeability.The former can be divided into two subtypes:network fracture,and single structural fracture,and the later can be divided into three subtypes:bedding fracture,low permeability pore,and extremely low permeability pore.The process for evaluating favorable FFFB zones was formed to define favorable development targets and support the well deployment for purpose of high production.The study results provide a reference for the exploration and development of deep tight sandstone oil and gas reservoirs in China. 展开更多
关键词 fault-fold-fracture body fracture control factor genetic characteristics geological model deep layer tight sandstone Xinchang structural belt Upper Triassic Xujiahe Formation Sichuan Basin
下载PDF
Coordinated control strategy for robotic-assisted gait training with partial body weight support 被引量:5
15
作者 秦涛 张立勋 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第8期2954-2962,共9页
Walking is the most basic and essential part of the activities of daily living. To enable the elderly and non-ambulatory gait-impaired patients, the repetitive practice of this task, a novel gait training robot(GTR) w... Walking is the most basic and essential part of the activities of daily living. To enable the elderly and non-ambulatory gait-impaired patients, the repetitive practice of this task, a novel gait training robot(GTR) was designed followed the end-effector principle, and an active partial body weight support(PBWS) system was introduced to facilitate successful gait training. For successful establishment of a walking gait on the GTR with PBWS, the motion laws of the GTR were planned to enable the phase distribution relationships of the cycle step, and the center of gravity(COG) trajectory of the human body during gait training on the GTR was measured. A coordinated control strategy was proposed based on the impedance control principle. A robotic prototype was developed as a platform for evaluating the design concepts and control strategies. Preliminary gait training with a healthy subject was implemented by the robotic-assisted gait training system and the experimental results are encouraging. 展开更多
关键词 协调控制策略 训练过程 机器人 步态 体重 设计理念 训练系统 GTR
下载PDF
Error Control Strategy in Ultrasonic Body Area Networks
16
作者 Wenbin Liu Yongjian Yang +1 位作者 Fan Wang En Wang 《China Communications》 SCIE CSCD 2016年第11期244-259,共16页
Recently,ultrasonic waves had been introduced as the transmission medium in Body Area Networks(BANs) to reduce the incalculable damage caused by radio waves. However,the communications based on ultrasonic waves suffer... Recently,ultrasonic waves had been introduced as the transmission medium in Body Area Networks(BANs) to reduce the incalculable damage caused by radio waves. However,the communications based on ultrasonic waves suffer from poor propagation of signals in air and consume too much energy. To address these limitations,firstly,we make the theoretical analysis to ensure ultrasonic waves could be used in BANs(UBANs). Then,we propose an error control strategy in UBANs to dynamically adjust the error control scheme and the Max-Retries based on the current channel state,which is called UECS. The UECS is based on IEEE 802.15.6 standards and considering the characteristics of ultrasonic waves in BANs. Simulation results show that UECS achieves better performance in terms of packet delivery ratio and energy consumption compared with the traditional strategies. 展开更多
关键词 控制策略 超声波 区域网络 网络传输介质 能源消耗 无线电波 控制方案 调整误差
下载PDF
STUDY ON DYNAMICS, STABILITY AND CONTROL OF MULTI-BODY FLEXIBLE STRUCTURE SYSTEM IN FUNCTIONAL SPACE
17
作者 XU Jian-guo(徐建国) +1 位作者 JIA Jun-guo(贾军国) 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2001年第12期1410-1421,共12页
The dynamics, stability and control problem of a kind of infinite dimensional system are studied in the functional space with the method of modern Mathematics. First, the dynamical control model of the distributed par... The dynamics, stability and control problem of a kind of infinite dimensional system are studied in the functional space with the method of modern Mathematics. First, the dynamical control model of the distributed parameter system with multi-body flexible and multi-topological structure was established which has damping, gyroscopic parts and constrained damping. Secondly, the necessary and sufficient condition of controllability and observability, the stability theory and asymptotic property of the system were obtained. These results expand the theory of the field about the dynamics and control of the system with multi-body flexible structure, and have important engineering significance. 展开更多
关键词 multi-body flexible system DYNAMICS STABILITY control functional space
下载PDF
The investigation on the improved quality of life before body X-knife therapy quality control in the patients with neoplasm
18
作者 李启明 张玉萍 李德志 《中国临床康复》 CSCD 2002年第10期1542-1542,共1页
Objective To provide improved manipulative program of body X-knife therapy is to re duce localization and repetition error,increase therapeutic precision and perform accurate quality control.Methods Measure and compar... Objective To provide improved manipulative program of body X-knife therapy is to re duce localization and repetition error,increase therapeutic precision and perform accurate quality control.Methods Measure and compare the actual error in 86therapeutic targets of52patients before body X-knife stereotactic radiotherapy at different positioning.Results The position error is reduced obviou sly in quality control group compared with control group.T here is prominent difference in two g roups about the error of irradiation field accuracy and axial superpo-sition(P value:0.000896and 0.02980).Conclusions The improved positioning method can reduce errors and increase repetiti on precision and veracity in therapy. 展开更多
关键词 体部X刀 肿瘤 生存质量
下载PDF
Stochastic Differential Game Model for Decentralized Power Control with Wisdom Regulation Factor in Wearable Audio-Oriented BodyNets
19
作者 Chen Yueyun Zhang Long Zhou Xianwei 《China Communications》 SCIE CSCD 2012年第12期117-126,共10页
In this study,aiming at the characteristics of randomness and dynamics in Wearable Audio-oriented BodyNets(WA-BodyNets),stochastic differential game theory is applied to the investigation of the problem of transmitted... In this study,aiming at the characteristics of randomness and dynamics in Wearable Audio-oriented BodyNets(WA-BodyNets),stochastic differential game theory is applied to the investigation of the problem of transmitted power control inconsumer electronic devices.First,astochastic differential game model is proposed for non-cooperative decentralized uplink power control with a wisdom regulation factor over WA-BodyNets with a one-hop star topology.This model aims to minimize the cost associated with the novel payoff function of a player,for which two cost functions are defined:functions of inherent power radiation and accumulated power radiation damage.Second,the feedback Nash equilibrium solution of the proposed model and the constraint of the Quality of Service(QoS) requirement of the player based on the SIR threshold are derived by solving the Fleming-Bellman-Isaacs partial differential equations.Furthermore,the Markov property of the optimal feedback strategies in this model is verified.The simulation results show that the proposed game model is effective and feasible for controlling the transmitted power of WA-BodyNets. 展开更多
关键词 偏微分方程 博弈模型 功率控制 随机性 分散力 调节因子 耐磨 智慧
下载PDF
风浪联合作用下分布式调谐质量阻尼器对海上半潜漂浮式风机的减振控制
20
作者 罗一帆 孙洪鑫 +3 位作者 王修勇 陈安华 彭剑 左磊 《振动工程学报》 EI CSCD 北大核心 2024年第4期565-577,共13页
海上半潜漂浮式风机在复杂深海环境下产生有害振动会威胁风机的安全性和耐久性,针对该问题并结合美国NREL的5 MW样机的漂浮平台几何结构构造,提出利用分布式调谐质量阻尼器(Tuned Mass Dampers,TMDs),即分别在漂浮平台的3根浮筒中布置T... 海上半潜漂浮式风机在复杂深海环境下产生有害振动会威胁风机的安全性和耐久性,针对该问题并结合美国NREL的5 MW样机的漂浮平台几何结构构造,提出利用分布式调谐质量阻尼器(Tuned Mass Dampers,TMDs),即分别在漂浮平台的3根浮筒中布置TMD,形成等边三角形布置,对随机风浪联合作用下海上半潜漂浮式风机的平台纵摇振动进行控制。为了更好地描述分布式TMDs对海上半潜漂浮式风机的减振效果,基于拉格朗日方程和模态叠加法,对海上半潜漂浮式风机-TMDs耦合系统提出并建立了9自由度多体动力学模型。基于H_(∞)算法,即以平台纵摇频响函数的峰值为优化目标,对分布式TMDs的参数进行优化设计,优化设计中考虑了3个TMDs之间的耦合关系。对风机-TMDs耦合系统开展了风浪联合作用下的数值模拟,分析了分布式TMDs对平台纵摇响应的减振效果。结果表明:最优设计下的分布式TMDs对海上半潜漂浮式风机平台纵摇振动具有良好的减振性能;在三种不同工况的随机风浪荷载作用下,分布式TMDs对平台纵摇固有频率附近的功率谱密度曲线峰值减振率和标准差减振率能分别达到39%和52%以上。 展开更多
关键词 振动控制 海上半潜漂浮式风机 多体耦合动力学模型 分布式调谐质量阻尼器 参数优化
下载PDF
上一页 1 2 114 下一页 到第
使用帮助 返回顶部