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    20 June 2007 Volume 34 Issue 3
      
    Original Articles
    New algorithm for stereo disparity estimation
    GUO Da-bo1;2;LU Zhao-yang1;HE Hua-jun1;JIAO Wei-dong1
    J4. 2007, 34(3):  337-341. 
    Abstract ( 2205 )   PDF (202KB) ( 1476 )   Save
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    To reduce the false match rate so as to increase Psnr and reduce computing complexity, a new algorithm for disparity estimation of the stereo image pair is proposed. Continuity and uniqueness constraints are employed to build up the Gaussian model for the computation of prior possibility, and the best matching block is determined according to maximum a posteriori (MAP) criterion. The angle of view constraint proposed in this paper and the ordering constraint, which are the pixels’ position range and sequence relation, are imposed to correct the Gaussian prior possibility calculation model which gives punishment to the candidate blocks that violate these two constraints. Constraints reduce the scanning range so that computing complexity and possibility of false matching are both reduced. Experimental results show that the proposed algorithm gives PSNR about 02~4.0 dB upgrade in contrast to the normalized correlation. In particular, images with more noise or bigger disparities will be given more upgrade. In addition, the disparity map obtained from the proposed algorithm has better smoothness than that from the normalized correlation.
    Study of neighbor discovery in wireless ad hoc networks with smart antennas
    ZHAO Rui-qin1;WEN Ai-jun1;LIU Zeng-ji1;YANG Jun-gang1;2
    J4. 2007, 34(3):  342-347. 
    Abstract ( 2307 )   PDF (200KB) ( 1333 )   Save
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    To obtain potentials offered by directional antennas which can increase the transmission range of a single hop, reduce interferences, improve the spatial reuse and then expand the capacity of the networks obviously, we propose two new directional neighbor discovery algorithms for MANET. The first is the Transmit Directionally only (TD) mode of the neighbor discovery algorithm with directional transmitting and omni-directional receiving. The second is the Transmit and Receive Directionally (TRD) mode of the neighbor discovery algorithm with directional transmitting and directional receiving. The two algorithms utilize the idea of imitating omni-directional transmission through circular directional transmission to discover neighbors without GPS or other aided information. Based on the CSMA/CA mechanism, a theoretical analysis of the discovery time and probability for a node to discover all neighbors are made, which is validated by NS-2 simulations. The key feature of the algorithms is accomplishing neighbor discovery without any assisted service such as GPS, time synchronization, etc.

    Fast method for Delaunay triangulation mesh generation in image representation
    JIAO Wei-dong;LU Zhao-yang;HUANG Jin
    J4. 2007, 34(3):  348-353. 
    Abstract ( 1693 )   PDF (206KB) ( 1063 )   Save
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    Considering the failure of real time coding application in the DT model-based image coding scheme, a fast method to generate the Delaunay Triangulation mesh for image representation based on the MV or MD criterion is proposed by using the idea of multi-resolution searching. It searches the mesh nodes with gradual subtle step length in generation of the mesh by which the total of searching points is reduced one by one,so time can be saved and the computational efficiency improved. Simulation result shows that the proposed method saves almost one half time while keeping finely reconstructed image quality compared with the general method based on the MV or MD criterion, and that it still can get more accurate image representation under the same mesh generation time compared with the other existing methods.
    Video network transmission of joint source-channel coded based on scene modeling
    KONG Fan-qiang;XIAO Song;ZHOU You-xi
    J4. 2007, 34(3):  354-359. 
    Abstract ( 2229 )   PDF (215KB) ( 1361 )   Save
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    A new method for combining source channel coding with source modeling and network congestion control for reliable video transmission over a wireless network is proposed. Based on the scene modeling and characteristic analysis, all layers encoded by MPEG-4 scalable coding are first classified into several types. Second, unequal loss protection and unequal error protection of queues are made according to their contribution to the quality of reconstructed video. Then the network congestion control strategy is adjusted according to different packet loss rates, and the rates between source coding and channel coding are dynamically adjusted according to BER in wireless channel. Finally, the experimental results show that the proposed scheme can achieve better performance compared with conventional schemes under various wireless network conditions.
    Improved multiplicative noisy polynomial interpolation algorithm in the finite field
    HUANG Hua-wei;LI Sheng-qiang;CHEN Ru-wei;XIAO Guo-zhen
    J4. 2007, 34(3):  360-362. 
    Abstract ( 2194 )   PDF (133KB) ( 941 )   Save
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    This paper analyses a multiplicative noisy polynomial interpolation algorithm in the finite field presented by J. von zur Gathen and I. E. Shparlinski and presents an amended algorithm. By the lattice reduction algorithm on the nearest vector presented by L.Babai, a more accurate estimate vector can be obtained and the coefficients of the multiple polynomial of the interpolation polynomial can be computed. Then the coefficients of the original interpolation polynomial can be computed. The amended algorithm reduces the lower bound of the order of the finite field and can apply to the polynomials in the finite field whose order is lower.
    Camera calibration method based on circular points
    ZHAO Lu-gang;WU Cheng-ke
    J4. 2007, 34(3):  363-367. 
    Abstract ( 1720 )   PDF (189KB) ( 1216 )   Save
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    An easy method for computing a camera internal parameters based on circular points is proposed. The proposed method only requires the camera to observe a planar calibration pattern which includes a circle and a pencil of its diameters, from at least three different orientations, and either the camera or the planar pattern can be moved freely. The motion need not be known, vanishing points and the vanishing line can be determined using the invariant of tangency, circular points can be computed through the intersection of the vanishing line with the ellipse, and then all the five intrinsic parameters can be determined linearly. The whole process needs to know neither any metric measurement on the model plane, nor the correspondences between points on images. Extensive simulations and experimental results with real images show that the proposed technique is both accurate and robust.
    Multiuser OFDM resource allocation algorithm for cognitive radio
    LI Wei-ying;CHEN Dong;XING Cheng-wen;WANG Ning
    J4. 2007, 34(3):  368-372. 
    Abstract ( 3007 )   PDF (190KB) ( 1856 )   Save
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    Based on the multiuser orthogonal frequency division multiplexing (MU-OFDM) technique and the characteristics of cognitive radio, a novel multiuser resource allocation algorithm is proposed. In this algorithm, the secondary users choose their subcarriers and powers to achieve their QOS requirements based on the knowledge of the channel detections. The maximal channel capability is achieved accordingly. A schedule parameter is introduced to fit the need of fairness between secondary users. Meanwhile a decline parameter and the terminal types are also considered during the subcarrier and power allocation, and the interference to the primary users is avoided. The algorithm is based on the two step method. As a result, calculations are reduced and the real time requirements are achieved. Simulation results indicate that our method can achieve about 40% performance improvement compared with FDMA in channel capability.

    Disparity estimation based on the gradient and MRF model
    HE Hua-jun;LU Zhao-yang;JIAO Wei-dong;GUO Da-bo
    J4. 2007, 34(3):  373-376. 
    Abstract ( 2214 )   PDF (161KB) ( 1116 )   Save
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    This paper presents a novel disparity estimation algorithm based on the gradient and Markov Random Field (MRF) model. First, the block matching algorithm combining gray and gradient information is adopted to obtain an initial disparity field. Second, an order matching constraint is applied to detect cross regions in the disparity-map. Finally, the erroneously matched blocks are corrected iteratively by MRF-based causality prediction to achieve a more accurate disparity field. Experimental results show that the proposed algorithm achieves a PSNR gain(about 1.2~1.8dB) as compared to the conventional block-based method and its calculating time is less than 1s.
    Method for traffic sampling in high-speed IPv6 networks
    PAN Qiao;PEI Chang-xing
    J4. 2007, 34(3):  377-381. 
    Abstract ( 1837 )   PDF (189KB) ( 1141 )   Save
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    Traffic sampling techniques are widely used for traffic measurements at a high link speed to prevent an exhaustion of resources and to limit the measurement costs. However, the challenge of an effective sampling method for IPv6-based networks is as yet unmet. This paper proposes a traffic sampling measurement method to take the challenge. For ensuring randomness of sample, we use entropy as an evaluation tool to analyze the bit randomness of each byte in IPv6 packet headers, and conclude that the last one byte of the Payload Length field and byte numbers 8, 12, 14, 15 and 16 of the IPv6 source and destination address fields which have both unchangeability during forwarding and high bit entropy values. We estimate whether a packet is sampled based on a hash function computed over the selected bytes. Therefore, the entire packet header content is not taken into account in our sampling method. The advantages of the method are improved randomness of the sample and the runtime efficiency of the sampling algorithm. Finally, through experiments using real IPv6 traffic traces, we prove that the sampled traffic data can correctly reflect the packet size distribution of full packet trace.
    Fast super-resolution image restoration approach
    XU Lu-ping;YAO Jing
    J4. 2007, 34(3):  382-385. 
    Abstract ( 1956 )   PDF (151KB) ( 1150 )   Save
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    In the research on the project onto convex set(POCS) super-resolution image restoration algorithm, it is observed that the edge region does not need the same relaxation factor as the uniform region. Revising this problem can reduce the large computational complexity of POCS and improve its practical application quality. Consequently, a fast POCS (FPOCS) is proposed. By quoting fuzzy entropy in the POCS image restoration process for edge detection, a monotonous increasing function that defines the relaxation factor is constructed based on the neighborhood homogeneous measurement (NHM). Therefore, the proposed approach can select the relaxation factor adaptively by the local character of the image. Experimental results show that the new approach can achieve a similar or even better restoration performance after dozens of iterations while the traditional POCS needs hundreds of iterations.
    Improved phase gradient autofocus algorithm based on adaptive isolated scatter selection
    LI Yan-ping;XING Meng-dao;BAO Zheng
    J4. 2007, 34(3):  386-391. 
    Abstract ( 2071 )   PDF (230KB) ( 1169 )   Save
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    If the scatter selected in phase gradient algorithm (PGA) algorithm is not isolated, the accuracy of the phase error estimation will be degraded. In this paper some modifications to the dominant scatter selection method are proposed, and then an improved PGA solution based on adaptive isolated scatter selection is presented. First, the quality of each pixel in the image is evaluated by a sliding window in the azimuth direction, and then the high quality scatters are selected for the phase error estimation, followed by multiple dominant scatters synthesis with the value of quality evaluated in order to improve the accuracy of the phase error estimation. Analysis and the results of real data processing show that the improved PGA algorithm outperforms the original one especially for the scene in which the bright scatters are not isolated.
    Symbol error probability analysis of orthogonal space-time block codes in the mixture noise
    WANG Xu-dong1;2;LIN Bin2;LIU Qi-zhong1
    J4. 2007, 34(3):  392-397. 
    Abstract ( 2112 )   PDF (247KB) ( 1070 )   Save
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    The performance of orthogonal space-time block codes (OSTBC) is investigated in the presence of an additive combination of impulsive and Gaussian noises. Based on maximum likelihood (ML) decoding, an equivalent approximate model with mixture noise is constructed for multiple input single output (MISO) systems. By using the moment generating function-based analysis approach, the closed-form expressions for the average symbol error rate (SER) of OSTBC over Rayleigh flat fading channels are derived. Furthermore, the SER performance of the STBC is analyzed for different code matrices with M-PSK and M-QAM modulations. Monte Carol simulation results show good agreement with the analyses.
    Balanced route arithmetic based noncooperative game theory
    ZHANG Hui-juan1;2;ZHOU Li-hua1;ZHAI Hong-ming3
    J4. 2007, 34(3):  398-401. 
    Abstract ( 2044 )   PDF (143KB) ( 1256 )   Save
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    Because of the unbalanced resource distribution in the path choice of the router, a new game-theoretic approach is presented, which regards the anycast route of IPv6 as an uncooperate game in many players. A game model with a player’s rate distribution stratety and delay avail in all paths is given. The player’s rate distribution which can assure the Nash equilibrium is solved. Based on the Nash Equilibrium, a balanced route arithmetic which asscures the best delay and the fair distribution in all players is presented. Simulation results indicate that this arithmetic can solve the balanced resource distribution in the router in effect.
    Image retrieval based on the texture and shape in the DCT compressed domain
    ZHAO Shan;ZHOU Li-hua
    J4. 2007, 34(3):  402-408. 
    Abstract ( 2142 )   PDF (258KB) ( 1098 )   Save
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    Image retrieval based on the texture and shape in the DCT compressed domain is proposed by introducing the spatial information of DCT blocks and DCT coefficients into the feature extraction. First, the definition of complex is introduced. Then, according to the complex of the DCT blocks and distribution of DCT coefficients, a weighted complex histogram is presented to extract the texture information. At the same time, DCT blocks are classified into different edges using the DCT coefficients directly and the edge-spatial distribution feature is adopted to describe the image shape. The statistical distribution of DCT blocks and the spatial distribution of DCT coefficients are taken into account in this paper, thus avoiding the wrong retrieval and missing retrieval. Experimental results show that the new method has a good performance in both retrieval efficiency and effectiveness.
    Content-based image retrieval based on Radon and wavelet transform
    AN Zhi-yong;WANG Xiao-hua;ZHAO Shan;ZHOU Li-hua
    J4. 2007, 34(3):  409-413. 
    Abstract ( 2288 )   PDF (172KB) ( 1130 )   Save
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    A new texture feature is proposed using the Radon and wavelet transform according to the geometric property of Radon transform and a new image retrieval algorithm based on the texture feature is presented. First, the orientation-normalized image is achieved by rotating its principal axis to the horizontal direction. It is turned to obtain the rotation-invariant project after the orientation-normalized image is done by the Radon transform. Second, the adoptive wavelet decomposition, which has the property of translation-and scale-invariance to the project of Radon transform, is constructed. Finally, the energy of every sub frequency band is extracted to be the texture feature of the image. The image retrieval experiments indicate that this method has the property of shift, scale and rotation invariance and has a higher retrieval-rate of 3.8% than the RIM method’s.
    Dynamic analysis and simulation of a spherical omnidirectional rolling robot
    LI Tuan-jie1;YAN Tian-hong2;ZHANG Xue-feng1
    J4. 2007, 34(3):  414-417. 
    Abstract ( 2024 )   PDF (146KB) ( 1230 )   Save
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    The method for dynamic modeling, analysis and simulation of a spherical omnidirectional rolling robot is developed. The kinematic model for the spherical robot is established according to the nonholonomic constraint acting on it. On the basis of its structural characteristics, its dynamic model is derived by applying the Lagrange-Routh equations. A strategy is given to eliminate the unknown Lagrange multipliers. Then a complete dynamic model for the spherical robot is obtained, which is a system of strong coupled second-order differential equations to control the robot’s motion. Finally a simulation model that describes the complete dynamic equations of the robot is established. The motion examples of the dynamic analysis and simulation are given to verify the correctness and validity of this approach.
    Electronic image stabilization system based on global features tracking
    ZHU Juan-juan;GUO Bao-long
    J4. 2007, 34(3):  418-422. 
    Abstract ( 2145 )   PDF (199KB) ( 1210 )   Save
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    This paper presents a robust video stabilization system with feature points tracking based global motion estimation and Kalman filtering based motion compensation. First, global motion is estimated from the local motions of selected feature points, each of which is tracked using feature window matching. Considering the stable relative positions between points’ sets, the distance criterion is proposed to make matching validation, which would delete moving points or mismatched points (i.e. , local features). Then, the global motion vector is decided to sub-pixel accuracy by substituting all validated pairs (i.e., global features) into a motion model and refined by the Levenberg-Marquardt method. Finally, the global motion parameters are accumulated to be Kalman filtered for correction. The experimental result illustrates that the proposed system is effective to stabilizing translational, rotational and zooming jitter and robust to local motions.
    Blind source separation method in the wavelet domain
    ZHAO Zhi-jin1;2;XIE Ting-ting2;LI Xiao-ping3;ZHAO Zhi-dong2
    J4. 2007, 34(3):  423-427. 
    Abstract ( 1982 )   PDF (197KB) ( 1053 )   Save
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    Because the performance of the blind source separation method based on generalized eigendecomposition for congruent pencils in the time domain is affected by the filter or delay, a blind source separation method based on generalized eigendecomposition for congruent pencils in the wavelet domain is proposed. Using the orthogonal property of wavelet, the non-gaussianity of the signals is increased and the difficulty in separating signals is decreased. Since the bi-orthogonal wavelet has the linear phase property and good approximation ability to signals, the generalized eigendecomposition for congruent pencils of wavelet coefficients is carried out, and the steady separation matrix is obtained. The algorithm not only retains the virtue of the time domain algorithm, but also can use two random numbers as the filter coefficients, and the time delay method used by it can separate the mixtures when the number of the sources is more than three. The simulation results of four voice signals verify the effectiveness of this method.
    Least square support vector machine based on parameters optimization of clone programming-cross validation and inertial component forecasting
    ZHANG Wei1;HU Chang-hua2;JIAO Li-cheng1;BO Lie-feng1
    J4. 2007, 34(3):  428-432. 
    Abstract ( 2510 )   PDF (207KB) ( 1118 )   Save
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    For improving the generalization ability of the least square support vector machine (LSSVM), the parameter optimization algorithm of clone programming-cross validation is employed to select optimal parameters of LSSVM. The clone programming algorithm has the superior capability in local and global search, and local minimums are refrained efficiently; cross validation has the unbiased estimator property, and therefore, the problems such as over training or insufficient training are avoided. In the optimization algorithm, the avidity function is constructed by the cross validation error, and moreover, optimal parameters of LSSVM are chosen by the clone programming algorithm. The time series forecasting model of the inertial component is built with LSSVM. Experimental results prove the effectiveness of the optimization algorithm and generalization ability of the forecasting model, and the forecasting model provides a support on dynamic compensation and fault forecasting of the inertial component.

    Computation of double reflection and the diffraction field of plane for UTD
    WANG Meng;CHEN Xiao-jie;LIANG Chang-hong
    J4. 2007, 34(3):  433-437. 
    Abstract ( 1721 )   PDF (200KB) ( 1041 )   Save
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    According to Huygens’ Principle, the computation of the second rank field of a flat plane can be solved by calling the first rank field function twice, so ray trace is the key. The method for the computation of the second rank field of the flat plane is deduced using the image method in this paper. For the ray trace of reflection-reflection, reflection-diffraction, and diffraction-reflection, the result can be easily obtained by using the image point of the source point or field point. For the diffraction-diffraction case, geometry is hybrid together with algebra to change the ray trace for the calculation of the equations system. Examples and analytical deduction show the validity of the method. Compared to the method of searching the points used before, the method derived in this paper is better in accuracy and speed.
    Study of the identification for the static temperature model and the method for compensating temperature of the accelerometer
    GUO Run-qiu;ZHANG Xiao-dong;WANG Cheng
    J4. 2007, 34(3):  438-442. 
    Abstract ( 1506 )   PDF (169KB) ( 883 )   Save
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    To eliminate the impact of temperature on accelerometer, by using the method of least square estimation, a law that the coefficients of the accelerometer model vary with temperature has been obtained, and the static temperature model of the accelerometer within 20℃~50℃ has also been established. The hardware system is composed of DSP(TMS320F240). After temperature compensation with the above model by the system, the magnitude of output change is 10-4, but without temperature compensation the magnitude of output change is 10-3, and the output of the accelerometer’s stability has a significant improvement.
    Experimental study of the electromagnetic polarization technique in a scattering environment
    ZHU Yong-zhong1;LI Ping2;ZHANG Dian-fu2
    J4. 2007, 34(3):  443-447. 
    Abstract ( 1917 )   PDF (179KB) ( 1101 )   Save
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    The independent channel capacity obtained in a scattering environment is three times more than that gained in the free environment. The extra channel capacity is gained because there are six distinguishable electric magnetic states of polarization at a given point, rather than two as is usually assumed. According to the characteristics that the scattering environment in which HF radio transmission spreads is always changing, comparisons are made by testing the relations between the voice quality of the composite polar channel voice received by a printed helix antenna (loaded whip antenna in the terminal) and distance. After comparing horizontal polarization, vertical polarization with circular polarization in tone quality for transmitting at the same frequency and distance (within 200km), a relationship is given between tone quality and transmitting distance. The voice levels of all three different polarization antennas are above 1, which shows that the electric and magnetic polarizations received on the carriers are not single horizontal polarization or vertical polarization. The experiment shows that the reliability of HF mobile communication can be raised by transmitting or receiving the same message through different polarizations. Based upon this theory, a novel model of multiple polarization antenna system is presented.
    Design of a reconfigurable wire antenna by genetic algorithm
    WEI Wen-bo;YIN Ying-zeng;LIU Qi-zhong
    J4. 2007, 34(3):  448-452. 
    Abstract ( 1972 )   PDF (171KB) ( 1256 )   Save
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    A reconfigurable wire antenna is optimized by the method of moment (MoM) combined with the genetic algorithm (GA). The switches of the reconfigurable antenna are regarded as loads, and the Sherman-Morrison-Woodbury equation is used to accelerate the calculation of the impedance matrix equation in MoM. The optimized results indicate that the combination of GA and the MoM is a very effective method to optimize the reconfigurable wire antennas, and the speed of optimization is improved over 3~4 orders of magnitude.
    Analysis of stochastic temperature field by the Neumann expansions
    LI Jin-ping;CHEN Jian-jun;LIU Hai-feng;XU Jian;HUANG Xiao-bian
    J4. 2007, 34(3):  453-457. 
    Abstract ( 1568 )   PDF (179KB) ( 878 )   Save
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    An analysis of the plate temperature field with the random heat transfer coefficient, heat exchange coefficient, heat flux density, environment temperature and heat source is made by the Neumann expansions Monte-Carlo stochastic finite element method. The computing formulas for the mean value and variance and possibility in some interval of node temperature are given. The effect of the amount of variances of random variables on node temperature response is considered by the example. The example in this paper shows that as the number of freedoms of the structure becomes greater, the method proposed has the advantage of high efficiency.
    Nonlinear snap-through characteristic of a compressed bi-stable buckled beam
    ZHAO Jian;JIA Jian-yuan;WANG Hong-xi;ZHANG Wen-bo
    J4. 2007, 34(3):  458-462. 
    Abstract ( 2119 )   PDF (167KB) ( 1253 )   Save
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    Based on the generalized variation principles and the bi-stable characteristics of a post-buckling beam, the nonlinear relationship between the transversal force and displacement is deduced by considering the effects of axial compression on the beam length constraint. The analytical expression for the transverse force is obtained by using the meromorphic function method. The nonlinear coupled relations among the transverse critical force, the axial compression and the buckling modes are also analyzed by utilizing the assumed buckling mode method. With the deduction above, the transverse forces for different arc heights of the pre-stressed buckling beam are given while the second bifurcation buckling occurs during the snap-through process. Simulation results are in good agreement with those from experiments and numerical methods, and hence, it can find applications in designing the MEMS bistable device.
    Decidability of the dense timed interval temporal logic
    ZHANG Hai-bin;DUAN Zhen-hua
    J4. 2007, 34(3):  463-467. 
    Abstract ( 2074 )   PDF (199KB) ( 1188 )   Save
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    We present a dense timed interval temporal logic (DTITL) and exploit the decidability problem of DTITL. To do so, we define an equivalence relation with finite equivalence classes over state spaces of DTITL models. Using the equivalence relation, we can construct a discrete model of a subset of the first order interval temporal logic called SFO from a continuous DTITL model. A set of rules are also applied to construct SFO formulas from DTITL ones. Then the satisfiability of DTITL is equivalently transformed to the same problem for SFO. Since the decidability of SFO can be transformed to the satisfiability of the propositional interval temporal logic, so SFO is decidable. Thus, the satisfiability of DTITL can be proved to be decidable.

    Modeling and numerical analysis on the reserve price of reverse auction
    XU Ya-qing1;WEI Yi-hua2;HU Qi-ying2
    J4. 2007, 34(3):  468-471. 
    Abstract ( 2026 )   PDF (147KB) ( 1047 )   Save
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    Based on the famous reverse auction website Priceline, this paper studies a problem of how to dynamically set reserve prices for some goods of the seller in a period of continuous time when customers arrive at Priceline one after another according to a non-stationary Poisson process, so that the seller can gain a maximal expected revenue. With the comparability of both revenue management and reverse auction, and the uniqueness of reverse auction, the optimal control model of the expected revenue for sellers is set up, and the following properties are obtained: 1) the concavity and monotonicity of the maximal expected revenue function, 2) the monotonicity of the marginal expected revenue function, and 3) the concavity of the optimal price. The results of numerical analysis are consistent with theoretical ones. It is also illustrated that the closer the bidding price is to the valuation, the more dominant Priceline will be to revenue management.
    Optimization algorithms on differentiable manifolds
    XIAO Gang;LIU San-yang;YIN Xiao-yan
    J4. 2007, 34(3):  472-475. 
    Abstract ( 1874 )   PDF (155KB) ( 1192 )   Save
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    The problem of the descent algorithm along geodesic on Riemannian manifolds is provided. A technique for the optimization algorithm for the differentiable function on differentiable manifolds is given. The constrained optimization problem is converted to the unconstrained case with the special choices of coordinate transformation and the optimality condition for the constrained optimization problem is given. Moreover, a mapping gradient method is developed and linear convergence of the mapping gradient method is established.

    Design of the manufacturing organization system for multi-lifecycles
    WANG An-min
    J4. 2007, 34(3):  476-480. 
    Abstract ( 1642 )   PDF (152KB) ( 926 )   Save
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    With the frequent increase in reconstruction, the rise of manufacturing organization cost and risk has become an increasingly important subject. From the point of view of the ecological organization theory, the paper proposes the concept of multi-lifecycle organization, and elaborates the definition qualification of organization multi-lifecycle circulation. Based on the structural and functional characters of the optimal organization unit, the paper presents the mechanism of organization multi-lifecycle circulation and evolution, as well as the design method for multi-lifecycle organization with the optimal organization unit as the basic structure cell. The method has the advantages of realizing organizational core competence duplication and evolution between generations and organizational resources cross lifecycle sharing, realizing the fast reconstruction of the manufacturing organization, and reducing the organizational reconstruction cost and the risk of organizational change.
    Intercarrier interference mitigation technique for OFDM systems in fast fading channels
    ZHAO Li1;2;CHEN Chen2;ZHANG Ping1
    J4. 2007, 34(3):  481-485. 
    Abstract ( 2336 )   PDF (191KB) ( 1242 )   Save
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    Doppler frequency offsets in rapid mobile environments result in both the fast fading of radio channels and intercarrier interference (ICI) in Orthogonal Frequency Division Multiplexing (OFDM) systems. In order to combat the impact of ICI on OFDM systems in fast fading channels, an ICI mitigation technique is proposed in this paper. The symbol shift cancellation method is used to cancel the impact of ICI on the far sub-carriers, then the adjacent sub-channel filter method is used to cancel the impact of ICI on the adjacent sub-carriers, and the fast fading channel is tracked and estimated by comb-type pilot-symbol scheme. By utilizing the distribution of the adjacent intercarrier interference after shift cancellation, the channel response matrix and adjacent interference filter method are simplified, and a special training pilot scheme is proposed to improve the accuracy of channel estimation. The proposed algorithm can achieve trade-off between the bandwidth efficiency and the complexity of ICI cancellation method. Simulation results show that the proposed technique can effectively improve BER performance of the OFDM system.
    Search model of P2P bases on tactics of ranking in group
    LU Wei;GUAN Lin-tao
    J4. 2007, 34(3):  486-489. 
    Abstract ( 1928 )   PDF (162KB) ( 996 )   Save
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    At present, the way of application for search for the resource on the P2P network, such as overabundance message, heavy loads on the Telecom backbone and low efficiency, etc. is not perfect. In this paper, based on the current P2P model and delay of communication, a new P2P model is presented which logically groups the network and grades the node in the group. Then we build the in-group and between-group search mechanisms. The new P2P model obviously improves search efficiency and reduces the message of searching, and it also enhances the expansion ability in-group search mechanism of the whole network system.
    Synthetic aperture sonar movement estimation using the robust kalman filter
    ZHU Pei-sheng1;2;HUANG Yong1;ZHANG Chun-hua1
    J4. 2007, 34(3):  490-494. 
    Abstract ( 1942 )   PDF (198KB) ( 1038 )   Save
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    In the synthetic aperture sonar (SAS) movement measurement system, a movement estimation algorithm based on the M-estimator in the Kalman filter is introduced to improve its robustness against the external sensors data containing outliers with unbounded errors. Using the M-estimator to optimize parameters estimation, estimation errors are minimized under a class of Huber function, and unlike kalman filter estimation errors under norm-2 are minimized. Since the M-estimator is not sensitive to unbounded errors,it can effectively overcome the effect of unbounded errors,and numerical experiments illustrate that the proposed method can solve this problem of the estimation of the SAS’ movement.
    Study of transmission characters of two kinds of new double-ridge waveguide
    CHEN Xiao-qiang1;LI Ming1;REN En-en1;LU Mai2
    J4. 2007, 34(3):  495-499. 
    Abstract ( 2614 )   PDF (187KB) ( 1293 )   Save
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    In order to find a new kind of symmetrical double ridged waveguide which has optimal transmission characters, the paper puts forward two kinds of novel double ridged waveguides which have triangle and anti-trapezoid ridges respectively. The TE mode’s cut-off wavelength and single-mode bandwidth of two kinds of novel double ridged waveguides are calculated by the finite element method. It is shown that the ridged waveguide would gain a higher single-mode bandwidth as the distance of ridges is closer by analyzing transmission character changes along with the change curve of the ridged waveguides’dimensions, and that the maximal single-mode bandwidth is 8.0173.The anti-trapezoid ridge waveguide’s cut-off wavelength is longer than rectangle, trapezoid and triangle ridged waveguides which have the same dimensions, and the maximal value is 9.5. These results could provide instructions for miniaturization of ridged waveguide apparatuses. Finally plotted field patterns of the dominant mode and the first higher order show that the field intensity change is most enormous at the triangle ridge waveguide’s peak, and that the energy loss is greater.
    Channel estimation for the wireless MIMO OFDM system based on modulatable orthogonal polyphase sequences
    LU Zhen1;WANG Yong2;GE Jian-hua2
    J4. 2007, 34(3):  500-504. 
    Abstract ( 3013 )   PDF (180KB) ( 1618 )   Save
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    Channel estimation based on training sequences in the time domain for wireless MIMO OFDM is proposed. The training sequences are modulatable orthogonal polyphase sequences. The time domain periodic autocorrelation of the sequence emanated from all the transmit antennas is completely ideal. The absolute value of the cross-correlation function between any two modulatabale sequences is constant and satisfies the mathematical lower bound. The multi-channel estimator relies on correlation between the received training sequences and the locally generated training sequences. The advantages of the proposed method, over existing alternatives, are low complexity and the ability to track the time-varying channel. Simulation results show satisfactory performance even at a low SNR.
    Construction of two sorts of cartesian authentication codes
    LIU Jin-long;XU Zong-ze
    J4. 2007, 34(3):  505-508. 
    Abstract ( 1744 )   PDF (163KB) ( 944 )   Save
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    A method to construct one sort of optimal Cartesian authentication codes by using the cyclic array is presented. The method is easy to realize and it needs no complicated calculation over group or finite fields. Another iterative means to construct one class of Cartesian authentication codes with the k sources and 1/n probabilities of successful impersonation and substitution attack is also proposed, where parameters k and n are two arbitrary positive integers. Compared with the Cartesian authentication codes constructed by Descartes product, the authentication codes produced by iterative means have far fewer encoding rules, when they contain the same parameters k and n.