期刊文献+
共找到77篇文章
< 1 2 4 >
每页显示 20 50 100
支撑跳跃教学方法改革新尝试 被引量:2
1
作者 方志军 王志刚 《体育教学》 2003年第2期46-46,共1页
关键词 支撑跳跃 教学方法 教学改革 踏跳技术 过马动作
下载PDF
Two Novel Hydroperoxylated Lycopodium Alkaloids from Huperzia serrata 被引量:3
2
作者 谭昌恒 马晓强 +2 位作者 周慧 蒋山好 朱大元 《Acta Botanica Sinica》 CSCD 2003年第1期118-121,共4页
Two novel hydroperoxylated Lycopodium alkaloids, 11alpha-hydroperoxyphlegmariurine B (1) and 7-hydroperoxyphlegmariurine B (2), along with a known compound, phlegmanurine B (3), were isolated from the total alkaloid f... Two novel hydroperoxylated Lycopodium alkaloids, 11alpha-hydroperoxyphlegmariurine B (1) and 7-hydroperoxyphlegmariurine B (2), along with a known compound, phlegmanurine B (3), were isolated from the total alkaloid fraction of the Chinese medicinal herb Huperzia serrata (Thunb.) Trev. Their structures and relative configurations were elucidated on the basis of spectroscopic analyses. 展开更多
关键词 Huperzia serrata Lycopodium alkaloids 11 alpha-hydroperoxyphlegmariurine B 7-hydroperoxyphlegmaniurine B
下载PDF
The MAP/PH(PH/PH)/1 Discrete-time Queuing System with Repairable Server 被引量:4
3
作者 禹海波 聂赞坎 杨建伟 《Chinese Quarterly Journal of Mathematics》 CSCD 2001年第2期59-63,共5页
In this paper, we discuss a discrete time repairable queuing system with Markovian arrival process, where lifetime of server, service time and repair time of server are all discrete phase type random variables. Using... In this paper, we discuss a discrete time repairable queuing system with Markovian arrival process, where lifetime of server, service time and repair time of server are all discrete phase type random variables. Using the theory of matrix geometric solution, we give the steady state distribution of queue length and waiting time. In addition, the stable availability of the system is also provided. 展开更多
关键词 discrete time queuing system reliability phase type distribution Markovian arrival process matrix geometric solution
下载PDF
广州地铁十三号线南岗站B口正式开通
4
作者 谢综文 《广东交通》 2018年第5期31-31,共1页
十三号线南岗站B口已完成验收工作,于9月11日正式开门迎客。此前南岗站已于2017年12月28日开通试运营,但该站B口因受征地拆迁影响未能与车站同步投入运营服务。据了解,南岗站已开通的C口位于黄埔东路东南侧,D口及E口位于黄埔东路西北侧。
关键词 口因 东路 过马 车站 广州 南岗 黄埔 影响
下载PDF
Quality prediction of batch process using the global-local discriminant analysis based Gaussian process regression model
5
作者 卢春红 顾晓峰 《Journal of Southeast University(English Edition)》 EI CAS 2015年第1期80-86,共7页
The conventional single model strategy may be ill- suited due to the multiplicity of operation phases and system uncertainty. A novel global-local discriminant analysis (GLDA) based Gaussian process regression (GPR... The conventional single model strategy may be ill- suited due to the multiplicity of operation phases and system uncertainty. A novel global-local discriminant analysis (GLDA) based Gaussian process regression (GPR) approach is developed for the quality prediction of nonlinear and multiphase batch processes. After the collected data is preprocessed through batchwise unfolding, the hidden Markov model (HMM) is applied to identify different operation phases. A GLDA algorithm is also presented to extract the appropriate process variables highly correlated with the quality variables, decreasing the complexity of modeling. Besides, the multiple local GPR models are built in the reduced- dimensional space for all the identified operation phases. Furthermore, the HMM-based state estimation is used to classify each measurement sample of a test batch into a corresponding phase with the maximal likelihood estimation. Therefore, the local GPR model with respect to specific phase is selected for online prediction. The effectiveness of the proposed prediction approach is demonstrated through the multiphase penicillin fermentation process. The comparison results show that the proposed GLDA-GPR approach is superior to the regular GPR model and the GPR based on HMM (HMM-GPR) model. 展开更多
关键词 quality prediction global-local discriminantanalysis Gaussian process regression hidden Markov model soft sensor
下载PDF
Degradation Process of Coated Tinplate by Phase Space Reconstruction Theory 被引量:4
6
作者 石江波 夏大海 +2 位作者 王吉会 周超 刘彦宏 《Transactions of Tianjin University》 EI CAS 2013年第2期92-97,共6页
The degradation process of organosol coated tinplate in beverage was investigated by electrochemical noise (EN) technique combined with morphology characterization.EN data were analyzed using phase space reconstructio... The degradation process of organosol coated tinplate in beverage was investigated by electrochemical noise (EN) technique combined with morphology characterization.EN data were analyzed using phase space reconstruction theory.With the correlation dimensions obtained from the phase space reconstruction,the chaotic behavior of EN was quantitatively evaluated.The results show that both electrochemical potential noise (EPN) and electrochemical current noise (ECN) have chaotic properties.The correlation dimensions of EPN increase with corrosion extent,while those of ECN seem nearly unchanged.The increased correlation dimensions of EPN during the degradation process are associated with the increased susceptibility to local corrosion. 展开更多
关键词 phase space reconstruction CHAOS electrochemical potential noise electrochemical current noise correlation dimension organic coating
下载PDF
On approximating multifractal traffic burstiness with Markov modulated Poisson processes 被引量:1
7
作者 纪其进 《Journal of Southeast University(English Edition)》 EI CAS 2004年第4期436-441,共6页
We investigate the approximating capability of Markov modulated Poisson processes (MMPP) for modeling multifractal Internet traffic. The choice of MMPP is motivated by its ability to capture the variability and correl... We investigate the approximating capability of Markov modulated Poisson processes (MMPP) for modeling multifractal Internet traffic. The choice of MMPP is motivated by its ability to capture the variability and correlation in moderate time scales while being analytically tractable. Important statistics of traffic burstiness are described and a customized moment-based fitting procedure of MMPP to traffic traces is presented. Our methodology of doing this is to examine whether the MMPP can be used to predict the performance of a queue to which MMPP sample paths and measured traffic traces are fed for comparison respectively, in addition to the goodness-of-fit test of MMPP. Numerical results and simulations show that the fitted MMPP can approximate multifractal traffic quite well, i.e. accurately predict the queueing performance. 展开更多
关键词 multifractal traffic Markov modulated Poisson processes queueing delay packet loss rate
下载PDF
An Optimized Vertical Handoff Algorithm Based on Markov Process in Vehicle Heterogeneous Network 被引量:4
8
作者 MA Bin DENG Hong +1 位作者 XIE Xianzhong LIAO Xiaofeng 《China Communications》 SCIE CSCD 2015年第4期106-116,共11页
In order to solve the problem the existing vertical handoff algorithms of vehicle heterogeneous wireless network do not consider the diversification of network's status, an optimized vertical handoff algorithm bas... In order to solve the problem the existing vertical handoff algorithms of vehicle heterogeneous wireless network do not consider the diversification of network's status, an optimized vertical handoff algorithm based on markov process is proposed and discussed in this paper. This algorithm takes into account that the status transformation of available network will affect the quality of service(Qo S) of vehicle terminal's communication service. Firstly, Markov process is used to predict the transformation of wireless network's status after the decision via transition probability. Then the weights of evaluating parameters will be determined by fuzzy logic method. Finally, by comparing the total incomes of each wireless network, including handoff decision incomes, handoff execution incomes and communication service incomes after handoff, the optimal network to handoff will be selected. Simulation results show that: the algorithm proposed, compared to the existing algorithm, is able to receive a higher level of load balancing and effectively improves the average blocking rate, packet loss rate and ping-pang effect. 展开更多
关键词 vehicle heterogeneous network vertical handoff markov process fuzzy logic multi-attribute decision
下载PDF
On Kendall's Conjecture for an Extended Birth-death Q-processes with Instantaneous State and Catastrophes 被引量:3
9
作者 WUQun-ying 《Chinese Quarterly Journal of Mathematics》 CSCD 2004年第1期41-46,共6页
A new structure with the special property that instantaneous state and catas-trophes is imposed to ordinary birth-death processes is considered. Kendall's conjecture forthe processes is proved to be right.
关键词 extended birth-death process instantaneous state Kendall's conjecture
下载PDF
A new analytical algorithm for computing probability distribution of project completion time
10
作者 侯振挺 张玄 孔祥星 《Journal of Central South University》 SCIE EI CAS 2010年第5期1006-1010,共5页
An analytical algorithm was presented for the exact computation of the probability distribution of the project completion time in stochastic networks,where the activity durations are mutually independent and continuou... An analytical algorithm was presented for the exact computation of the probability distribution of the project completion time in stochastic networks,where the activity durations are mutually independent and continuously distributed random variables. Firstly,stochastic activity networks were modeled as continuous-time Markov process with a single absorbing state by the well-know method of supplementary variables and the time changed from the initial state to absorbing state is equal to the project completion time.Then,the Markov process was regarded as a special case of Markov skeleton process.By taking advantage of the backward equations of Markov skeleton processes,a backward algorithm was proposed to compute the probability distribution of the project completion time.Finally,a numerical example was solved to demonstrate the performance of the proposed methodology.The results show that the proposed algorithm is capable of computing the exact distribution function of the project completion time,and the expectation and variance are obtained. 展开更多
关键词 stochastic activity networks project completion time distribution function Markov process supplementary variable technique
下载PDF
Active Contours and Mumford-Shah Segmentation Based on Level Sets
11
作者 NASSIR H.SALMAN 刘重庆 《Journal of Shanghai Jiaotong university(Science)》 EI 2003年第1期48-53,共6页
This paper is to detect regions (objects) boundaries, also to isolate and extract individual components from a medical image. This can be done using an active contours to detect regions in a given image, based on tech... This paper is to detect regions (objects) boundaries, also to isolate and extract individual components from a medical image. This can be done using an active contours to detect regions in a given image, based on techniques of curve evolution, Mumford Shah functional for segmentation and level sets. The paper classified the images into different intensity regions based on Markov random field, then detected regions whose boundaries are not necessarily defined by gradient by minimizing an energy of Mumford Shah functional for segmentation which can be seen as a particular case of the minimal partition problem. In the level set formulation, the problem becomes a mean curvature flow like evolving the active contour, which will stop on the desired boundary. The stopping term does not depend on the gradient of the image, as in the classical active contour and the initial curve of level set can be anywhere in the image, and interior contours are automatically detected. The final image segmentation is one closed boundary per actual region in the image. 展开更多
关键词 active counters level set methods SEGMENTATION energy minimization shape recovery Markov random field
下载PDF
A Novel Dynamic Decision Model in 2-player Symmetric Repeated Games
12
作者 Liu Weibing Wang Xianjia Wang Guangmin 《Engineering Sciences》 EI 2008年第1期43-46,共4页
Considering the dynamic character of repeated games and Markov process, this paper presented a novel dynamic decision model for symmetric repeated games. In this model, players' actions were mapped to a Markov decisi... Considering the dynamic character of repeated games and Markov process, this paper presented a novel dynamic decision model for symmetric repeated games. In this model, players' actions were mapped to a Markov decision process with payoffs, and the Boltzmann distribution was intousluced. Our dynamic model is different from others' , we used this dynamic model to study the iterated prisoner' s dilemma, and the results show that this decision model can successfully be used in symmetric repeated games and has an ability of adaptive learning. 展开更多
关键词 game theory evolutionary game repeated game Markov process decision model
下载PDF
Efficient Temporal Difference Learning with Adaptive λ
13
作者 毕金波 吴沧浦 《Journal of Beijing Institute of Technology》 EI CAS 1999年第3期251-257,共7页
Aim To find a more efficient learning method based on temporal difference learning for delayed reinforcement learning tasks. Methods A kind of Q learning algorithm based on truncated TD( λ ) with adaptive scheme... Aim To find a more efficient learning method based on temporal difference learning for delayed reinforcement learning tasks. Methods A kind of Q learning algorithm based on truncated TD( λ ) with adaptive schemes of λ value selection addressed to absorbing Markov decision processes was presented and implemented on computers. Results and Conclusion Simulations on the shortest path searching problems show that using adaptive λ in the Q learning based on TTD( λ ) can speed up its convergence. 展开更多
关键词 dynamic programming delayed reinforcement learning absorbing Markov decision processes temporal difference learning Q learning
下载PDF
Optimization of the CBSMAP Queueing Model
14
作者 Kondrashova E.V 《Journal of Mathematics and System Science》 2013年第7期359-364,共6页
The present paper is devoted to the research of controlled queueing models at control of CBSMAP (Controlled Batch Semi-Markov Arrival Process). The control is based on the theory of controlled semi-markov processes ... The present paper is devoted to the research of controlled queueing models at control of CBSMAP (Controlled Batch Semi-Markov Arrival Process). The control is based on the theory of controlled semi-markov processes for system optimization. The control is carried out using a type of the next batch and moments of batch arrivals. 展开更多
关键词 Controlled queuing models OPTIMIZATION controlled process controlled arrival-flow
下载PDF
Survivability modeling and analysis on 3D mobile ad-hoc networks 被引量:2
15
作者 彭三城 王国军 +1 位作者 胡忠望 陈建平 《Journal of Central South University》 SCIE EI CAS 2011年第4期1144-1152,共9页
Most existing work on survivability in mobile ad-hoc networks(MANETs) focuses on two dimensional(2D) networks.However,many real applications run in three dimensional(3D) networks,e.g.,climate and ocean monitoring,and ... Most existing work on survivability in mobile ad-hoc networks(MANETs) focuses on two dimensional(2D) networks.However,many real applications run in three dimensional(3D) networks,e.g.,climate and ocean monitoring,and air defense systems.The impact on network survivability due to node behaviors was presented,and a quantitative analysis method on survivability was developed in 3D MANETs by modeling node behaviors and analyzing 3D network connectivity.Node behaviors were modeled by using a semi-Markov process.The node minimum degree of 3D MANETs was discussed.An effective approach to derive the survivability of k-connected networks was proposed through analyzing the connectivity of 3D MANETs caused by node misbehaviors,based on the model of node isolation.The quantitative analysis of node misbehaviors on the survivability in 3D MANETs is obtained through mathematical description,and the effectiveness and rationality of the proposed approach are verified through numerical analysis.The analytical results show that the effect from black and gray attack on network survivability is much severer than other misbehaviors. 展开更多
关键词 mobile ad-hoc networks (MANETs) SURVIVABILITY node behaviors semi-Markov process network connectivity
下载PDF
Bed Load Transport Rates during Scouring and Armoring Processes 被引量:6
16
作者 YANG Fengguang LIU Xingnian CAO Shuyou HUANG Er 《Journal of Mountain Science》 SCIE CSCD 2010年第3期215-225,共11页
Dambreak-induced bed scouring may undermine the foundation of bridge piers and other structures,and that destruction can pose a serious threat.Consequently,this paper aims at exploring the mechanisms of scouring and a... Dambreak-induced bed scouring may undermine the foundation of bridge piers and other structures,and that destruction can pose a serious threat.Consequently,this paper aims at exploring the mechanisms of scouring and armoring.Firstly,the incipient velocity for nonuniform sediment particles was studied,and a formula was derived based on the angle of repose of nonuniform sediment.The results showed that the mechanism of incipient motion for sand and fine gravel differed from that for coarse gravel and cobbles.Also,comparison between experimental and field data shows that the results from the proposed formula agree well with those observed for all conditions.Secondly,a birth-death,immigration-emigration Markov process was developed to describe the bed load transport rate associated with scouring and armoring.The comparison between experimental data and computed results shows that our model can predict the bed load transport rate,although there may be some limitations,the chief of which is that there are many variables in the model to be determined through experiment.This makes its application in river engineering inconvenient. 展开更多
关键词 Nonuniform sediment angle of repose bed scour armoring incipient velocity bed loadtransport
下载PDF
Evolutionary Game Dynamics in a Fitness-Dependent Wright-Fisher Process with Noise 被引量:3
17
作者 全吉 王先甲 《Communications in Theoretical Physics》 SCIE CAS CSCD 2011年第9期404-410,共7页
Evolutionary game dynamics in finite size populations can be described by a fitness-dependent Wright- Fisher process. We consider symmetric 2×2 games in a well-mixed population. In our model, two parameters to de... Evolutionary game dynamics in finite size populations can be described by a fitness-dependent Wright- Fisher process. We consider symmetric 2×2 games in a well-mixed population. In our model, two parameters to describe the level of player's rationality and noise intensity in environment are introduced. In contrast with the fixation probability method that used in a noiseless case, the introducing of the noise intensity parameter makes the process an ergodic Markov process and based on the limit distribution of the process, we can analysis the evolutionary stable strategy (ESS) of the games. We illustrate the effects of the two parameters on the ESS of games using the Prisoner's dilemma games (PDG) and the snowdrift games (SG). We also compare the ESS of our model with that of the replicator dynamics in infinite size populations. The results are determined by simulation experiments. 展开更多
关键词 evolutionary games Wright-Fisher process evolutionary stable strategy noise
下载PDF
The Stability of Logistic Model with Random Impulse
18
作者 LI Jun-ping HOU Zhen-ting 《Chinese Quarterly Journal of Mathematics》 CSCD 2009年第1期1-9,共9页
This paper is devoted to studying the stability of Logistic model with random impulse by using the theory of Markov skeleton processes and a convenient condition for Logistic model with random impulse to be stable is ... This paper is devoted to studying the stability of Logistic model with random impulse by using the theory of Markov skeleton processes and a convenient condition for Logistic model with random impulse to be stable is given. 展开更多
关键词 Logistic model Markov skeleton process random impulse STABILITY
下载PDF
A Brief Analysis on BMW'S Automatic Transmission Problems and Treatment
19
作者 Chao Chen 《International Journal of Technology Management》 2013年第3期14-15,共2页
the article analyses the principles AT work, and a detailed analysis of BMW's automatic transmission failures, and maintenance process.Maintenance of other automatic transmission provides a certain degree of signific... the article analyses the principles AT work, and a detailed analysis of BMW's automatic transmission failures, and maintenance process.Maintenance of other automatic transmission provides a certain degree of significance. 展开更多
关键词 automatic transmission thilure analysis lault example
下载PDF
Separation Processes of Granular Materials by Sizes at the Sieve Classifiers
20
作者 Fail Gabdulbarovich Akhmadiev R.F. Gizzjatov 《Journal of Chemistry and Chemical Engineering》 2013年第1期56-63,共8页
A mathematical model of the kinetics of thin-layer separation of granular materials by size stacked sieve classifiers based on the theory of Markov processes is constructed. The probability of screening in a cell in t... A mathematical model of the kinetics of thin-layer separation of granular materials by size stacked sieve classifiers based on the theory of Markov processes is constructed. The probability of screening in a cell in the shape and size of the holes and particle sieve material shared with the influence of the relative speed of their movement was determined. Residues on whole meal with sieves were identified by a kinetic model and numerical calculations, the efficacy of separation. 展开更多
关键词 Multilevel classifier sieve separation process probability sieving the density distribution Fokker-Planck equation.
下载PDF
上一页 1 2 4 下一页 到第
使用帮助 返回顶部