Resource allocation for MIMO-OFDMA downlink based cognitive radio systems with imperfect channel learning

This paper is concerned with the resource allocation for multiple input multiple output and orthogo- nal frequency division multiplexing access （MIMO-OFDMA） downlink cognitive radio systems where a cognitive radio MIMO-OFDMA system is under spectrum sharing with an existing primary radio （PR） network. We use the channel learning scheme to estimate the channel information from cognitive radio transmitter （CR-TX） to PR and then make beamforming to transmit signal. Considering the interference from CR-TX to PR caused by the imperfect channel learning, we intend to maximize CR throughput under the interference power constraint at PR and CR transmit power constraint. A nearly optimal subcarrier and power allocation algorithm with linear complexity is proposed. The proposed algorithm is global optimal when the maximum transmit power is beyond certain threshold. Simulation results show that the proposed algorithm has a good performance very close to the global optimal algorithm.     

Joint optimal sensing time and power allocation for multi-channel cognitive radio networks considering sensing-channel selection

In this paper,we consider a multi-channel cognitive radio network(CRN)where each secondary user(SU)can only choose to sense a subset of channels.We formulate a joint optimization problem of sensingchannel selection,sensing time and power allocation under the constraints of average transmit power budget and average interference power budget,which maximizes the CRN’s total throughput.We propose a greedy algorithm to solve the joint optimization problem,which has much less computational complexity.Moreover,it is shown that the search space of the greedy algorithm can be further pruned.Finally,numerical results demonstrate that the greedy algorithm has comparable performance to the exhaustive search algorithm.     

On the ?2 stability of time varying linear and nonlinear discrete time MIMO systems

New conditions are derived for the l2-stability of time-varying linear and nonlinear discrete-time multiple-input multipleoutput （MIMO） systems, having a linear time time-invariant block with the transfer function F（z）, in negative feedback with a matrix of periodic/aperiodic gains A（k）, k = 0,1, 2,... and a vector of certain classes of non-monotone/monotone nonlinearities φp（-）, without restrictions on their slopes and also not requiring path-independence of their line integrals. The stability conditions, which are derived in the frequency domain, have the following features： i） They involve the positive definiteness of the real part （as evaluated on ｜z｜ = 1） of the product of Г （z） and a matrix multiplier function of z. ii） For periodic A（k）, one class of multiplier functions can be chosen so as to impose no constraint on the rate of variations A（k）, but for aperiodic A（k）, which allows a more general multiplier function, constraints are imposed on certain global averages of the generalized eigenvalues of （A（k ＋ 1）,A（k））, k = 1, 2 iii） They are distinct from and less restrictive than recent results in the literature.     

Whitening of fractional order polynomial autoregressive Non-Gaussian impulsive stable colored noise

This paper proposes a new different spectral density from power spectrum density of second order processes, thus we can get a new concept of stable white noise based on covariation function and covariation spectrum density. And a new technique is suggested for the estimation of the parameters of polynomial autoregressive （PAR） nonlinear colored noise processes with stable white noise excitations. Simultaneously, a simple whitening method is employed for polynomial autoregressive nonlinear stable colored noise.     

Context-awareness approach in game style application

By combining training content with Game AI, Game Style Training can provide a rich, interactive and engaging educational substance. It supports experiential learning-bydoing. And it can contribute to promote interest and motivation of trainees. In this paper, a Context-Awareness Approach （CAA） is put forward for earthquake rescue training by applying the concept of ambient intelligence. The CAA takes advantage of player profile to monitor player states, utilizes time sensor and location sensor to supervise environment changes. And then, a Reinforcement Learning model based on MAS is designed to update game AI system.     

Topology control for directed diffusion in wireless sensor networks

Due to severely constrained energy, storage capacity and computing power for nodes in wireless sensor network, the routing protocols have become a hot research topic. Directed diffusion is a communication paradigm for information dissemination in sensor networks based on data-centric routing. An energy efficient hybrid adaptive clustering for directed diffusion is presented in the paper. The main goal is to curb the interests flooding overhead by clustering. Hybrid of active and passive clustering creation is used to make tradeoff between maintenance cost and delay. The adaptive turning off the radio of redundant nodes and rotation of cluster heads is used to save energy. The ns-2 simulating results show that the protocol has good performances in energy consuming, delivery ratio and delay without leading to too much overhead comparing with existing directed diffusion protocols.     

Spatial Data Sharing on Grid

The Internet technology has already changed the Information Society in profound ways, and will continue to do so. Nowadays many people foresee that there is a similar trajectory for the next generation of Internet - Grid Technology. As an emerging computational and networking infrastructure, Grid Computing is designed to provide pervasive, uniform and reliable access to data, computational and human resources distributed in a dynamic, heterogeneous environment. On the other hand, the development of Geographic Information System （GIS） has been highly influenced by the evolution of information technology such as the Internet, telecommunications, software and various types of computing technology. In particular, in the distributed GIS domain, the development However, due to the closed and centralized has made significant impact in the past decade. legacy of the architecture and the lack of interoperability, modularity, and flexibility, current distributed GIS still cannot fully accommodate the distributed, dynamic, heterogeneous and speedy development in network and computing environments. Hence, the development of a high performance distributed GIS system is still a challenging task.
So, the development of Grid computing technology undoubtedly provides a unique opportunity for distributed GIS, and a Grid Computing based GIS paradigm becomes inevitable. This paper proposes a new computing platform based distributed GIS framework - the Grid Geographic Information System （G^2IS）.     

Automatic analysis of textual garden path phenomenon： A computational perspective

This paper puts forward a text-circled semantic schema by which a special flow chart of cognitive alteration and processing breakdown in Machine Translation （MT） system is clearly presented. Based on the theoretical analysis of textual Garden Path Phenomenon （GPP）, we devise a formula to measure the dramatically changeable value of textual GPP. The data-provided evidence in A Farewell to Arms shows the textual GPP can motivate the development of plots and adjust the analyst＇s original horizon of expectation. Despite the limitation of incompatible, subjective and sample-restricted features involved in the theoretical framework and formula, this computational analysis makes MT system pay more attention to text-circled cognitive alteration rather than only highlight the lexical or syntactic translation, and as a result aims to make the effectiveness of machine translation of the literary text improved.     

Maximizing Networking Capacity in Multi-Channel Multi-Radio Wireless Networks

Providing each node with one or more multi-channel radios offers a promising avenue for enhancing the network capacity by simultaneously exploiting multiple non-overlapping channels through different radio interfaces and mitigating interferences through proper channel assignment. However, it is quite challenging to effectively utilize multiple channels and/or multiple radios to maximize throughput capacity. The National Natural Science Foundation of China（NSFC） Project61128005 conducted comprehensive algorithmic-theoretic and queuing-theoretic studies of maximizing wireless networking capacity in multi-channel multi-radio（MC-MR） wireless networks under the protocol interference model and fundamentally advanced the state of the art. In addition, under the notoriously hard physical interference model, this project has taken initial algorithmic studies on maximizing the network capacity, with or without power control. We expect the new techniques and tools developed in this project will have wide applications in capacity planning, resource allocation and sharing, and protocol design for wireless networks, and will serve as the basis for future algorithm developments in wireless networks with advanced features, such as multi-input multi-output（MIMO） wireless networks.     

Quadrature Kalman Filter （QKF） and Reduced Quadrature Kalman Filter （R-QKF） in Ballistic Target Tracking

Recently there have been researches about new efficient nonlinear filtering techniques in which the nonlinear filters generalize elegantly to nonlinear systems without the burdensome lineafization steps. Thus, truncation errors due to linearization can be compensated. These filters include the unscented Kalman filter （UKF）, the central difference filter （CDF） and the divided difference filter （DDF）, and they are also called Sigma Point Filters （SPFs） in a unified way. For higher order approximation of the nonlinear function. Ito and Xiong introduced an algorithm called the Gauss Hermite Filter, which is revisited in [5]. The Gauss Hermite Filter gives better approximation at the expense of higher computation burden, although it＇s less than the particle filter. The Gauss Hermite Filter is used as introduced in [5] with additional pruning step by adding threshold for the weights to reduce the quadrature points.     

Accurate Modeling of the Spiral Bevel and Hypoid Gear with a New Tooth Profile

Distinguishing with traditional tooth profile of spiral bevel and hypoid gear, it proposed a new tooth profile namely the spherical involute. Firstly, a new theory of forming the spherical involute tooth profile was proposed. Then, this theory was applied to complete parametric derivation of each part of its tooth profile. For enhancing the precision, the SWEEP method used for formation of each part of tooth surface and G1 stitching schema for obtaining a unified tooth surface are put forward and made the application in the accurate modeling. Lastly, owing to the higher accuracy of tooth surface of outputted model, it gave some optimization approaches. Given numerical example about the model can show that this designed gear with spherical involute tooth profile can achieve fast and accurate parametric modeling and provide a foundation for tooth contact analysis （TCA） in digitized design and manufacture.     

ICI compensation in MISO-OFDM system affected by frequency offset and phase noise

In MISO-OFDM system, ICI which is caused by frequency offset and phase noise breaks down orthogonality between sub-carriers and degrades system performance. In this paper, to compensate integrated effect of frequency offset and phase noise, several ICI self-cancellation methods are proposed; and CPE, ICI and CIR are derived theoretically in MISO-OFDM system. As results, by choosing several ICI self-cancellation methods appropriately, considerable performance improvement can be achieved in the MISO-OFDM system which affected by frequency offset and phase noise.     

Program Design of Graphic Realism Displaying System Based on DXF Lathe Turning Rotational Parts

For virtually realizing the graphic realism display of DXF machine parts, in AutoCAD2007 graphic drawing environment, an interactive experimental method was taken to realize the display of graphic in DXF, which was taken as the data-exchanged interface and source. Based on depth analysis of DXF data structure, take one drawing of DXF lathe turning rotational part asthe test piece. By VC＋＋6.0 programming, part＇s geometry information could be obtained. Through data processing, 3D data of the test piece could be generated, which is based on 2D data of DXF test piece. Then, OpenGL graphic processing technologies （light, material, texture, map, et al.） were applied on the 3D display of test piece from DXF files or program modules. Finally based on the test report, results of the system functions were shared to prove the realization of system design, and the feasibility of algorithms used. In the developed software, Machine Designers could get a full view of machine parts, and do some proper modifications. The study content and results of our work have some theory and practical significance on the application of program design in the practical projects.     

Un-thorough Delaunay Approach for Tetrahedral Mesh Generation

An integrated tetrahedrization algorithm in 3D domain which combines the Delaunay tetrahedral method with un-Delaunay tetrahedral method is described. The algorithm was developed by constructing Delaunay Tetrahedrons from a scattered point set, recovering boundaries using Delaunay and un-Delaunay method, inserting additional nodes in unsuitable tetrahedrons, optimizing tetrahedrons and smoothing the tetrahedral mesh with the 2D-3D Laplacian method. The algorithm has been applied to the injection molding CAE preprocessing.     

Determination of primitive element in Gauss integral domain module p residue system zp[i]

analysis on researching find wide The primary origin of algebraic numbers is the finite field Zp[i], which is derived from Gauss＇ on arithmetic of Z[i]. Primitive element theories application in cryptography. Some theon＇es is discussed on how to determine numbering methods in. finite field primitive element and the Zp[i] generated by Gauss integral domain Z[i]. The research result will be of important value in secret communication.     

A differential evolutionary based algorithm for multiuser OFDMA system adaptive resource allocation

In this paper, the problems of radio resource allocation for Orthogonal Frequency Division Multiple Access （OFDMA） systems are addressed. The main goal of this paper is to present and analyze base station allocation of subcarriers and adaptive modulation. We impose a set of proportional fairness constraints to assure that each user can achieve a required data rate. Since the optimal solution to the fairness problem is extremely computationally complex to obtain, we propose an adaptive radio resource allocation method based on differential evolutionary algorithm for multiuser OFDMA system. The performance of the described schemes is further evaluated in numerical experiments. We improve the convergence of the differential evolutionary algorithm through the method of elitist selection and adding some individuals with ＇good＇ genes to the initial population. Simulation results show that out proposed algorithm better than static subcarrier allocation schemes TDMA in muhiuser OFDMA system.     

无线传感器网络基于能量效率的路由协议综述

本文介绍了无线传感器网络的体系结构及其相关问题,对近年来针对于无线传感器网络提出的路由协议进行了研究,并基于能量效率对其中几种典型路由协议进行了分析和比较,最后展望了无线传感器网络路由协议未来的研究方向。     

Study of Lyapunov exponent spectra for axial-flow compression system

The Lyapunov exponent spectra of the axial-flow compression system＇s Moore-Greitzer model was researched with chaos theory. When the parameter B of the MG model is greater （surge） or smaller （stall）, the system＇s Lyapunov exponent spectra are all （0, -）. So the compressor＇s working points are all on a limit circle, when the compressor is in the state of surge or stall. When the compressor is surge, it can come into a full limit circle, but in the stall, it can not. The conclusion was applied to detect the stall of the compressor. The numerical experimentation results demonstrate that the method can exactly detect the stage of the first stall before the start of deep rotating stall.