Showing papers in "Journal of Beijing University of Posts and Telecommunications in 2007"

Dynamic Modeling of Bicycle Robot and Nonlinear Control Based on Feedback Linearization of MIMO Systems

Abstract: A kind of dynamic model of bicycle robot was built based on the lagrange method. To keep bicycle self-balance,the steering angle,the roll-angle and the rear wheel velocity were taken as system outputs;the steering,mass balancing and rear-wheel toque were taken as inputs.Therefore,a multi-input and multi-output(MIMO) affine nonlinear system was constructed.Then input-output linearization control theory was applied to analyze the affine nonlinear system,so that the equal linear system was achieved by exact linearization.By analysis of the equal linear system and state feedback method,the desired pole locations were realized.Computer simulations verified the validity of the control algorithm.

On the Laws of Information-Knowledge-Intelligence Transforms

Abstract: A new subject,the study of the laws of information-knowledge-intelligence transforms,is firstly proposed.The background and implications of the subject are explained.The framework and the fundamental concepts of the subject are then explicated,and the major results achieved so far within the subject are also briefly reported.It is pointed out that the research of the subject may open up a huge room for scientific discoveries and technological innovations and thus present great significance and wide foreground for applications.

A Service Implementation Scenario Measuring Users' QoE

Abstract: Based on the introduction of qiality of experience(QoE) and key performance index(KPI),a measurable QoE evaluation algorithm for Internet differentiated service is proposed.Its implementation scenario that can measure and evaluate users' QoE is described.The important roles of QoE,used as a quantitative specification of perceptive quality of service(QoS) for service users,for service provider to improve their QoS base on this scenario are also analyzed.

A Mining Algorithm with Alarm Association Rules Based on Statistical Correlation

Abstract: Currently those algorithms to mine the alarm association rules are limited to the minimal support,so that they can only obtain the association rules among the frequently occurring alarm events,To address this problem,a new mining algorithm based on the statistical correlation was proposed,which firstly acquired the alarm net units with the same character by clustering;and then discovered the association rules from both high-frequency and low-frequency alarm events with the high correlativity and the high confidence.Experimental results demonstrated that this algorithm was efficient and accurate to mine the association rules among alarm events with both high-frequency and low-frequency.

Fast Antenna Selection Algorithms for Distributed MIMO Systems

Abstract: A norm and correlation based antenna selection algorithm(NCBA) and its modified version(NCBA-M) are proposed for the downlink transmit antenna selection in distributed multiple input multiple output(MIMO)systems.The performance of the proposed algorithms is compared with that of norm based antenna selection algorithm(NBA) and large scale fading based antenna selection algorithm(LFBA) respectively.The simulation result shows that when no correlation of the transmit antenna correlation in the same antenna port is considered,NBA,LFBA and NCBA have similar performance to the optimal antenna selection algorithms.However,when transmit antennas in the same port have strong correlations,NBA and LFBA result in a high capacity loss,but NCBA-M can still approach the performance of optimal antenna selection algorithm.

Research on the Climbing and Jumping of a Spherical Rolling Robot

Abstract: The problem of a spherical rolling robot's climbing capability is analyzed and the related climbing experiment is introduced.A method of phase plane is used to investigate the movement of the spherical rolling robot before jumping and its jumping condition is developed.The dynamic model of the spherical rolling robot after jumping is derived using the D'Alembet principle.The feasibility of the theoretical analysis for the spherical rolling robot is verified by the results of simulation and experiment.

Rough Set Theory Based Fault Diagnosis of Node in Wireless Sensor Network

Abstract: For facilitating the efficient routing planning,node management for upper computers or sink nodes,long-distance node service and prolonging the lifetime of wireless sensor network(WSN),a new method for node fault diagnosis in WSN is proposedThe attribute reduction for decision-making of fault diagnosis is found based on the discriminate matrix in rough set theoryThe algorithms of node fault classification are proposed based on attribute matchingThe fault can be located and diagnosed individually for each node and module in WSNSimulations show that the proposed method yields high diagnosis accuracy with low communication cost and energy consumptionIt is suitable for wireless sensor networks with stringing energy limits

A Novel Approach for Solving Nonreciprocal Transmission Line Problems Using Standard Smith Chart

Abstract: A new approach for solving complicated nonreciprocal transmission line(NTL) problems using standard Smith chart is proposed.Based on a nonlinear mapping,it transforms the parameters of NTL model into the parameters of traditional reciprocal transmission line(RTL) model.As a result,the design and calculation in NTL can be easily done by using a standard Smith chart(SSC).The effectiveness and convenience of the approach is tested through the complete design process of NTL single-stub series-matching and NTL double-stub parallel matching network.

A Novel Mode Selection Algorithm for H.264 Inter Frames

Abstract: The suitable mode-class is adaptively selected for the current macroblock(MB) based on the context of encoded MB-modes in the spatiotemporal neighborhoods of the previous and current H.264 video frames.Two matrixes which are composed of sum of absolute values of the integer transform coefficients in 4×4-residual-block contained in luminance 16×16-block and 8×8-block are defined respectively,the novel MB and sub-MB mode selection criteria which use the derived gradients of the two matrixes are then proposed.Experiments show that the proposed algorithm can averagely save about 11% and 7% encoding time compared to joint video team(JVT)-J033 and JVT-K021 respectively with almost no rate distortion efficiency degradation.

Fast Ordering Detection Algorithm for V-BLAST System

Abstract: A new ordering method and detection algorithm based on the Schmidt decomposition for the multiple-input multiple-output(MIMO) system are proposed.The algorithm can achieve the same bit error rate(BER) performance as the traditional zero forcing serial interference cancellation(ZF-SIC) algorithm while the computational complexity of the proposed algorithm is 1/3 to 2/3 to the traditional ZF-SIC algorithm.Analysis and computer simulation are also presented to verify the algorithm.

Autonomic Joint Session Admission Control Using Reinforcement Learning

Abstract: A reinforcement learning based joint session admission control(JOSAC) algorithm is proposed to realize the autonomic and distributed joint resource optimization between the heterogeneous radio access technologies(RAT) in a reconfigurable system.By introducing Q-learning into the admission control algorithm and adjusting the strength of the reinforcement signals for different types of sessions considering the inherent characteristics of different RATs,the characteristics of RATs is driven to absorb the suitable traffic for a proper service distribution.That will improve the efficiency of resource utilization.The simulation results show that,through the "trial-and-error" on-line learning process,overlapping RATs can converge to the optimized admission control policies that reduce the overall blocking probability and achieve lower handover dropping probability as well as higher revenue.

A Network Selection Algorithm Based on Fuzzy Analytic Hierarchy Process in Heterogeneous Systems

Abstract: Network selection problem in wireless local area network(WLAN) and universal mobile telecommunications system(UMTS) integrated network was studied using fuzzy analytic hierarchy process.A novel network selection algorithm was proposed.It combines analytic hierarchy process and fuzzy comprehensive evaluation.By analyzing the factors that influence network selection in integrated systems,a network selection decision-making model was founded and the weights of these factors were calculated.A method for calculating relative-membership grade was proposed by analysis of fuzzy comprehensive evaluation model.Total membership grade was calculated through relative-membership grade and the weights of these factors.The optimum network was selected according to total membership grade.The validity and accuracy of the algorithm was confirmed by the simulation.

An Intrusion Tolerance Model and Quantizing Analysis

Abstract: To improve the service ability under hostile intrusion,intrusion tolerance technology was studied and an improved intrusion tolerance model was built.Intrusion tolerance ability was mainly quantified and discussed by the model.Conceptions of intrusion tolerance degree,integrity degree and security degree were proposed.Some correlated factors which can influence intrusion tolerance degree were analyzed.And quantizing simulation and solution were carried out.The conclusion showed that it was meaning to design intrusion tolerance system.

A Sine-Like Wave Modulation Technique of xMax

Abstract: Through the specification analysis of xMax technique,a realization method of xMax is ela~borated.On this basis,a new method to realize the xMax by the way of sine-like wave modulation is proposed.This modulation technique realizes the information carrying through the method of single cyclical modulation to a kind of sine-like wave signal.The technique can achieve the xMax requirements of narrow bandwidth,low sideband power spectral density,extremely low emissive power and high transmission speed.Analysis and simulation show that the bandwidth of peak power spectrum is 300 kHz,the sideband power spectral density is 40 dB lower than peak value of power spectrum density,which enables the sideband to be able to hide well in the background noise;and transmission speed may be achieved to 7.5 Mbit/s.

Denoising by ICA Based on EMD Virtual Channel

Abstract: A method integrated by independent component analysis(ICA) and empirical mode decomposition(EMD) is proposed,which can eliminate the white noise from different signals.The superiority of ICA and EMD is expatiated emphatically.The basic theory and the detailed courses of construction of virtual noise channel used EMD are described.Based on time-frequency spectral characteristic of white noise,the principle of select intrinsic mode function(IMF),used the Hilbert time-frequency spectra,is proposed to reconstruct virtual noise channel.The simulations indicate that the denoising performance is effective.Compared with the denoising performance,this method is better than traditional wavelet method.

An Improved AODV Algorithm for WiFi Mesh Networks

Abstract: A routing algorithm utilizing the multi-rate and multi-range characteristic in wireless fidelity(WiFi) mesh networks is proposed.A cross-layer design scheme is newly introduced.The mechanism of adaptive data-rate transition in physical layer is considered in this algorithm.The maximum data-rate is used as the performance metric when establishing the route,and the minimum hop-count is regarded as a criterion under the same data-rate.The method to discover the path under different data-rate is presented.It will adjust the transmitted power level and expand the transmission range step by step when failed to establish the route within the given area.When the proposed algorithm is adopted,the Ad hoc on-demand distance vector(AODV) routing can be improved as WiFi-AODV.Simulation results show that WiFi-AODV is capable of establishing a route which has high data-rate,short link-delay and greate network throughput.

An Efficient Proxy Ring Signature Scheme

Abstract: An efficient proxy ring signature scheme was proposedThe original signer firstly signs a warrant and then the proxy signers in the ring generate their proxy private keys and finally,each proxy signer can finally generate a proxy ring signature using the modified identity based ring signature proposed by ChowStrong unforgeability of the new scheme was proven to rely on CDH problem by using forking lemma for ring signature under the random oracle modelNo pairing operation is required for the generation of a proxy ring signature and only two pairing operations are required for the verificationComparing with the existing schemes,the new scheme is more efficient in computation

A comparative study on business ecosystem and biological ecosystem

Abstract: Based on the results achieved by scholars at home and abroad on the comparative study of business ecosystem and biological ecosystem,this paper poses an analytical framework for comparison from 6 aspects including external circumstances and from 27 investigation pointsIn addition,the commonness and difference of the two ecosystems are concluded by means of analyses and synthesesAccordingly,it may serve as a referential basis for those scholars and enterprise supervisors who want to attain a better understanding of the business ecosystem for practice

Forward Displacement Analysis of the 4SPS-2CCS Generalized Stewart Platform

Abstract: A 4SPS-2CCS generalized Stewart platform is put forward and its forward displacement is analyzed.Based on quaternion,the model of the forward displacement solutions is built up.In order to obtain the number of solutions of this kind mechanism,Mourrain variety is used.The results show that the number of the forward displacement solutions of the parallel mechanism has at most 160.In addition, all the 160 solutions have been obtained by using homotopy continuation method. The example shows that the upper bound of 160 solutions can be reached in the general case.In stead of using Euler angle rotation matrix,the use of quaternion can reduce the Bezout number of the equations and the calculation time to increase the efficiency,and make the computer program easy to write.The result is verified by a numerical example.

Study of Noise Coupled Digital Auto-Gain Compensative Microwave Radiometer

Abstract: The observation of extremely low radiation brightness temperature signal of atmospheric objectives with airborne radiometer is critical to the service of artificial rainfall and collection of meteorological data.A new airborne noise coupled digital auto-gain compensative microwave radiometer(NDMR) was designed.Using compensative technique automatically,the stability and sensitivity of such system was improved greatly.The noise signal was input into the antenna and reference source through two couplers respectively,so the instrument can detect the slight variation in the micro-wave signal in cloud within relatively wide dynamic range.The results show that NDMR was reliable for the atmospheric observation on airborne platform under the circumstance of super-cooled water.Compared to the ground-based weather radar,the instrument gained more accurate data and detected local region directly,so it enhance the detection accuracy and sampling representative.

A Multilevel Congestion Control Routing Algorithm for Network-on-Chip

Abstract: A multilevel congestion control(MLCC) network-on-chip routing algorithm was proposed to improve the routing efficiency.When there happens medium and high level congestion,MLCC will decide how to do congestion control depending on the congestion level difference of the routers.Simulation results show that MLCC maintains low latency than one level congestion control routing algorithms under uniform traffic and transpose traffic.

Texture Image Retrieval with Radon and Wavelet Transform

Abstract: A new kind of texture image retrieval algorithm based on Radon and wavelet transform is presented.Firstly,the Radon transform is used to deal with retrieval image.Centering the Radon projection of image by its center of mass can eliminate the shift effect.The statistical value of projection can be used to normalize the projection matrix.Then the translation,rotation and scale-invariant wavelet coefficients of the projection can be attained by using a TSI wavelet transform along θ and t directions.Secondly,the energy of every sub frequency bands is extracted to be the texture feature of image.The Gaussian model is used to normalize the different sub-characters distance to the texture feature of image.Thirdly,the texture similarities of images are computed by the Canberra distance.The image retrieval experiments indicate that this method is robustness to the noises in image's similarity retrieval and has a higher retrieval-rate than other methods'.

Research of Almost Perfect Punctured Binary Sequence Pairs

Abstract: A new perfect correlation signal was proposed,which can be called as almost perfect punctured binary sequence pairs.Its properties and combinatorial admissibility conditions were studied.By making use of these properties and conditions,the searching efficiency for the almost perfect punctured binary sequence pairs can be improved significantly.A computational algorithm is compiled to find out a set of almost perfect punctured binary sequence pairs.The searching results show that the existent range of almost perfect punctured binary sequence pairs is so wide that they are suitable for engineering applications.

Worm Detection with Improved V-detector Algorithm

Abstract: A host usually changes its network traffic characteristics when infected by a worm.From the observation,a worm detection method was proposed.It drew inspiration from the negative selection of the immune system.Firstly,V-detector algorithm—a real-valued negative selection algorithm with variable-coverage detectors was improved.The improved algorithm endeavored to generate large detectors according to the non-self space distribution.Compared with V-detector,the improved algorithm generated a much smaller detector set and increased the detection efficiency.Secondly,the improved V-detector algorithm was used to generate detector sets and monitor hosts' network traffic characteristics for worm attacks.Experiments show that the method is effective to detect traditional worms as well as multi-vector polymorphic worms.

Fault Detection Mechanism Based on Probe Cycle Cover in Meshed Optical Burst Switching Networks

Abstract: An economical fault detection method,employing cycle cover theory,is proposed in terms of costly sing-hop test module in meshed optical burst switching(OBS) networks.Three kinds of cycle cover finding algorithms,heuristic depth first searching(HDFS),shortest path Eulerian matching(SPEM) and heuristic spanning-tree(HST) based cycle finding,are used to find cycle cover for meshed OBS networks.A probe module is then assigned for each cycle,and a fault detection mechanism based on probe cycle cover is formed.The computation and statistic results show that the proposed mechanism can reduce the cost of fault detection deeply compared to single-hop test scheme in meshed OBS networks.

Research on the SLA-based service modeling and parameter mapping

Abstract: For the purpose of implementing integrative and accurate service level agreement (SLA)-based service management, the SLA parameter representation and parameter mapping are studied. Firstly, SLA representation parameters are defined from different perspectives, the analytical method of bidirectional data flow is also proposed to extract representation parameters, and then parameter mapping mechanism is adopted as well to study correlation among data. The hierarchical SLA-based service management data model viewed from multi-perspectives is established. Secondly, analytic hierarchy process (AHP) combined with other different judging arithmetic is introduced to perform correlative computing. It realizes the mapping of representation parameters among sub-layers. Finally, service management data model of file transfer protocol (FTP) service over universal mobile telecommunication systems (UMTS) network is built and parameter mapping arithmetic is validated. The simulation results demonstrate that the proposed approach is rational and valid.

The Routing of Multi-Area and Hierarchy in the ASON

Abstract: The routing infrastructure of multi-area and hierarchy in the automatically switched optical network(ASON) was researchedA notification mechanism of topology information based on speaker node is proposed,which realizes topology discovery,synchronization and routing computation in the hierarchical networkThe simulation showed that the size of routing load and link state database(LSDB) was rapidly decreased with the increase of routing layersThis mechanism can solve the scalability of the network,save the memory space of the node and improve the routing efficiency

Research on TDOA Estimating Algorithms

Abstract: The acquisition probability of two popular algorithms are investigated,which are based on general cross correlation(GCC) algorithm and widely used to evaluate time difference of arrival(TDOA) coefficients.A numerical algorithm is proposed to calculate the acquisition probability of GCC,which lays a basis for the comparison between these two algorithms.In order to evaluate the TDOA,one of these algorithms is correlating the input signals directly while the other correlates the two input signals with a noiseless m-sequence separately.The simulation result proves that the later has higher algorithm efficiency.

A Scheduling Algorithm for Guarantying QoS of Streaming Traffic over Mixed Services

Abstract: A scheduling algorithm based on the two dimensional utility function is proposed to guarantee the packet drop ratio and play-out outage ratio of streaming application in the mixed service scenario.The simulation results show that guarantee capability for the drop and play-out outage ratio of the proposed scheme outperforms the modified-largest weighted delay first algorithm and exponent proportional fair algorithm,which only take the head-of-line delay into consideration.