检索结果-南通市图书馆

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

通信系统性能仿真评估算法的研究

系统仿真学报 2004年第3期16卷 390-392页

作者：王聪江光杰解放军理工大学通信工程学院南京210007 解放军理工大学指挥自动化学院南京210007

建模与仿真技术的应用为解决复杂大系统的性能评估提供了一种有效的技术手段。本文主要侧重于对仿真结果的评估,提出了以云模型为基础的系统性能评估算法。该评估算法用云理论实现定性属性值和定量属性值之间的转换。该评估算法以不确... 详细信息

建模与仿真技术的应用为解决复杂大系统的性能评估提供了一种有效的技术手段。本文主要侧重于对仿真结果的评估,提出了以云模型为基础的系统性能评估算法。该评估算法用云理论实现定性属性值和定量属性值之间的转换。该评估算法以不确定性为出发点,在理论上借鉴了层次分析法的某些处理手段,可以较好地处理指标体系中广泛存在的泛层次树形结构现象,使评估结果更加可信。实践表明,该方法对于复杂系统的综合评价更为方便、可行。

关键词：性能评估云模型仿真通信系统

在线全文

学校读者我要写书评

暂无评论

设计模式在通信系统仿真软件中的应用

系统仿真学报 2004年第4期16卷 677-680页

作者：王聪周胜军江光杰解放军理工大学通信工程学院南京210007 解放军理工大学指挥自动化学院南京210007

对大型、复杂系统性能评估的最好方法是系统仿真和建模,仿真软件的设计是实现仿真目的的关键。对于这种复杂软件的开发,目前最好的方法是利用软件工程的方法,而设计模式现在则成为软件工程中不可缺少的方法。目的在于对设计模式在仿真... 详细信息

对大型、复杂系统性能评估的最好方法是系统仿真和建模,仿真软件的设计是实现仿真目的的关键。对于这种复杂软件的开发,目前最好的方法是利用软件工程的方法,而设计模式现在则成为软件工程中不可缺少的方法。目的在于对设计模式在仿真软件中的应用做一些探讨,利用设计模式来提高仿真软件的可靠性、安全性、可用性和可维护性。

关键词：系统仿真软件工程设计模式通信系统

在线全文

学校读者我要写书评

暂无评论

无线个域网应用环境下速率自适应算法的研究

通信学报 2004年第4期25卷 160-167页

作者：叶芝慧沈连丰沈克勤陈锦泰东南大学移动通信国家重点实验室江苏南京210096 解放军理工大学指挥自动化学院江苏南京210007 香港中文大学电子工程学系

首先对无线个域网(WPAN)应用环境下的干扰模型进行了分析,在此基础上提出了在WPAN工作的系统中引入速率自适应控制算法以提高诸系统的抗干扰性能,并减小对系统内其它设备及不同系统间设备的相互干扰.文章对自适应速率控制算法进行了分析... 详细信息

首先对无线个域网(WPAN)应用环境下的干扰模型进行了分析,在此基础上提出了在WPAN工作的系统中引入速率自适应控制算法以提高诸系统的抗干扰性能,并减小对系统内其它设备及不同系统间设备的相互干扰.文章对自适应速率控制算法进行了分析,然后以蓝牙系统为例,给出了自适应速率控制算法对蓝牙系统性能改善的程度,重点讨论了对系统误比特率的影响.仿真结果显示,在理想反馈信道条件下,随着单信道信噪比的改善,自适应速率控制系统的最佳误比特率比固定速率传输系统有1～3个数量级的改善;即使采用简单的双速率自适应控制系统,也可以得到1～2个数量级的改善.由此得到的结果同样可应用于其它工作于无线个域网的系统.

关键词：无线个域网自适应速率控制固定速率系统蓝牙系统 IEEE 802.11b

One-step estimation for varying coefficient models

在线全文

学校读者我要写书评

暂无评论

science china Mathematics 2005年第2期48卷 198-213页

作者： TANG Qingguo & WANG Jinde Department of Mathematics, nanjing university, nanjing 210093, china institute of sciences, pla university of science and technology, nanjing 210007, china Department of Mathematics Nanjing University Nanjing China institute of sciences PLA University of Science and Technology Nanjing China

A one-step method is proposed to estimate the unknown functions in the varying coefficient models, in which the unknown functions admit different degrees of smoothness. In this method polynomials of different orders are used to approximate unknown functions with different degrees of smoothness. As only one minimization operation is employed, the required computation burden is much less than that required by the existing two-step estimation method. It is shown that the one-step estimators also achieve the optimal convergence rate. Moreover this property is obtained under conditions milder than that imposed in the two-step estimation method. More importantly, as only one minimization operation is employed, the full asymptotic properties, not only the asymptotic bias and variance, but also the asymptotic distributions of the estimators can be derived. The asymptotic distribution results will play a key role for making statistical inference.

关键词： varying coefficient model, one-step estimation, asymptotic distribution, optimal convergence rate.

Interactive group decision making procedure based on uncertain multiplicative linguistic preference relations

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2010年第3期21卷 408-415页

作者： Zeshui Xu1,2,1.College of Economics and Management,Southeast university,nanjing 210096,P.R.china 2.institute of sciences,university of science and technology of the pla,nanjing 210007,P.R.china College of Economics and Management Southeast University Nanjing 210096 P. R. China institute of sciences University of Science and Technology of the PLA Nanjing 210007 P. R. China

Group decision making problems are investigated with uncertain multiplicative linguistic preference *** unbalanced multiplicative linguistic label set is introduced,which can be used by the experts to express their linguistic preference information over *** uncertain linguistic weighted geometric mean operator is utilized to aggregate all the individual uncertain multiplicative linguistic preference relations into a collective one,and then a simple approach is developed to determine the experts＇ weights by utilizing the consensus degrees among the individual uncertain multiplicative linguistic preference relations and the collective uncertain multiplicative linguistic preference ***,a practical interactive procedure for group decision making is proposed based on uncertain multiplicative linguistic preference relations,in which a possibility degree formula and a complementary matrix are used to rank the given ***,the proposed procedure is applied to solve the group decision making problem of a manufacturing company searching the best global supplier for one of its most critical parts used in assembling process.

关键词： group decision making uncertain multiplicative linguistic preference relations unbalanced multiplicative linguistic label set consensus degree interaction.

A new policy to solve routing conflicts in shuffle-exchange networks

在线全文

学校读者我要写书评

暂无评论

science china(Information sciences) 2011年第7期54卷 1512-1523页

作者： GE FangBin 1,ZHAO Min 1,ZHANG Tao 1 & WANG JianXin 2 1 College of command automation pla university of science and technology,nanjing 210007,china 2 institute of china Electronic System Engineering,Beijing 100039,china College of command automation pla university of science and technology Nanjing China institute of china Electronic System Engineering Beijing China

Batch routing is an important approach for solving routing conflicts in SE (shuffle-exchange) ***,the complexity of batching and the uncertainty of batch size makes this approach *** on sequence division and routing coding concepts,we propose a method for detecting routing conflicts in an SE network,known as dividing detection that is more efficient than the method for window *** addition,a new conjecture relating to routing policies in SE networks is *** is proved using a constructive approach when n < *** on the conjecture,a new routing scheme for SE networks is *** this scheme,all the input signals can be transfered without conflicts and within two batches,while the efficiency of the batch routing is noticeably improved.

关键词： shuffle-exchange network sequence division routing coding transition sequence educed sequence

Effective capacity region of two-user opportunistic spectrum access

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science china(Information sciences) 2011年第9期54卷 1928-1937页

作者： XU YuHua,WANG JinLong & WU QiHui institute of Communications Engineering,pla university of science and technology,nanjing 210007,china institute of Communications Engineering PLA University of Science and Technology Nanjing China

The effective capacity region of the two-user opportunistic spectrum access (OSA) system in Rayleigh fading environment is derived in this *** OSA is a contemporary research topic,little attention has been given to the capacity analysis under quality-of-service (QoS) ***,we use the effective capacity,which is a powerful tool to analyze the QoS requirements in wireless communication systems,to study the sustainable packet arrival rate of the secondary users while meeting statistical QoS *** derive the effective capacity region of the two-user OSA system and propose a method to obtain the capacity region *** addition,by combining the finite state channel model and the activity of the primary user,an extended finite state channel model for the two-user OSA system is also proposed.

关键词： cognitive radio opportunistic spectrum access effective capacity

Stability of a linear oscillator with damping force of the fractional-order derivative

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science china(Physics,Mechanics & Astronomy) 2010年第2期53卷 345-352页

作者： WANG ZaiHua1,2 & HU HaiYan1 1 institute of Vibration Engineering Research,nanjing university of Aeronautics and Astronautics,nanjing 210016,china 2 institute of science,pla university of science and technology,nanjing 211101,china institute of Vibration Engineering Research Nanjing University of Aeronautics and Astronautics Nanjing China institute of science PLA University of Science and Technology Nanjing China

It begins with the study of damping representation of a linear vibration system of single degree of freedom (SDOF),from the view point of fractional calculus. By using the idea of stability switch,it shows that the linear term involving the fractional-order derivative of an order between 0 and 2 always acts as a damping force,so that the unique equilibrium is asymp-totically stable. Further,based on the idea of stability switch again,the paper proposes a scheme for determining the stable gain region of a linear vibration system under a fractional-order control. It shows that unlike the classical velocity feedback which can adjust the damping force only,a fractional-order feedback can adjust not only the damping force,but also the elastic re-storing force,and in addition,a fractional-order PDα control can either enlarge the stable gain region or narrow the stable gain region. For the dynamic systems described by integer-order derivatives,the asymptotical stability of an equilibrium is guaranteed if all characteristic roots stay in the open left half-plane,while for the systems with fractional-order derivatives,the asymptotical stability of an equilibrium is guaranteed if all characteristic roots stay within a sector in the complex plane. Analysis shows that the proposed method,based on the idea of stability switch,works effectively in the stability analysis of dynamical systems with fractional-order derivatives.

关键词： vibration system fractional-order derivative asymptotical stability stability switch

Delayed Hopf bifurcation in time-delayed slow-fast systems

在线全文

学校读者我要写书评

暂无评论

science china(Technological sciences) 2010年第3期53卷 656-663页

作者： ZHENG YuanGuang1 & WANG ZaiHua1,2 1 institute of Vibration Engineering Research,nanjing university of Aeronautics and Astronautics,nanjing 210016,china 2 institute of science,pla university of science and technology,nanjing 211101,china institute of Vibration Engineering Research Nanjing University of Aeronautics and Astronautics Nanjing China institute of science PLA University of Science and Technology Nanjing China

This paper presents an investigation on the phenomenon of delayed bifurcation in time-delayed slow-fast differential *** the two delayed's have different *** delayed bifurcation means that the bifurcation does not happen immediately at the bifurcation point as the bifurcation parameter passes through some bifurcation point,but at some other point which is above the bifurcation point by an obvious *** a time-delayed system,the evolution of the system depends not only on the present state but also on past *** this paper,the time-delayed slow-fast system is firstly simplified to a slow-fast system without time delay by means of the center manifold reduction,and then the so-called entry-exit function is defined to characterize the delayed bifurcation on the basis of Neishtadt's *** shows that delayed Hopf bifurcation exists in time-delayed slow-fast systems,and the theoretical prediction on the exit-point is in good agreement with the numerical calculation,as illustrated in the two illustrative examples.

关键词： time delay delayed bifurcation Hopf bifurcation slow-fast systems exit-point entry-exit function