Loading...

Table of Content

    30 December 2011, Volume 16 Issue 6 Previous Issue    Next Issue

    Articles
    For Selected: Toggle Thumbnails
    Articles
    Reputation-Based Collaborative Spectrum Sensing Scheme in Cognitive Radio Networks
    ZHAO Shi-kang (赵士康), HE Di (何 迪), LI Wen-hua (李文化), ZHU Fu-sheng (朱伏生)
    2011, 16 (6):  641-647.  doi: 10.1007/s12204-011-1204-6
    Abstract ( 2297 )  
     Collaborative spectrum sensing is
    proposed to improve the detection performance in cognitive radio
    (CR) networks. However, most of the current collaborative sensing
    schemes are vulnerable to the interference of the malicious
    secondary users (SUs). In this paper we propose a reputation-based
    collaborative spectrum sensing scheme to improve the security of
    cooperative sensing by mitigating the impacts of misbehaviors. The
    fusion center calculates the reputation rating of each SU according
    to their history reports to weight their sensing results in the
    proposed scheme. We analyze and evaluate the performance of the
    proposed scheme and its advantages over previous schemes in
    expansibility and integrity. Simulation results show that the
    proposed scheme can minimize the harmful influence from malicious
    SUs.
    References | Related Articles | Metrics
    Optimization Design of Two-Stage Operational Amplifier with Frequency Compensation via Geometric Programming
    LI Dan (李 丹), RONG Meng-tian (戎蒙恬), SHU Guo-hua (殳国华)
    2011, 16 (6):  648-651.  doi: 10.1007/s12204-011-1205-5
    Abstract ( 1384 )  
     An optimization design technique to
    obtain global solution for a two-stage operational amplifier
    (op-amp) with frequency compensation is presented. This frequency
    compensation technique can adjust the equivalent resistance to
    guarantee that the phase margin is stable even though circumstance
    temperature varies. Geometric programming is used to optimize the
    component values and transistor dimensions.  It is used in this
    analog integrated circuit design to calculate these parameters
    automatically.  This globally optimal amplifier obtains minimum power
    while other specifications are fulfilled.
    References | Related Articles | Metrics
    A Selection Scheme for Optimum Number of   Cooperative Secondary Users in Spectrum Sensing
    LIN Ying-pei (林英沛), HE Chen (何 晨), JIANG Ling-ge (蒋铃鸽), HE Di (何 迪)
    2011, 16 (6):  652-657.  doi: 10.1007/s12204-011-1206-4
    Abstract ( 1412 )  
     An optimization scheme for choosing the
    optimum number of secondary users in cooperative spectrum sensing
    based on the cyclostationary feature detection with Neyman-Pearson
    criterion is proposed in this paper. The optimal soft combination
    test statistic for the cooperative spectrum sensing based on
    cyclostationary feature detection is derived according to the
    generalized likelihood ratio test and its corresponding detection
    performance is deduced. A target function, considering two important
    parameters as the resource use efficiency and the number of samples
    employed by each cooperative secondary user in the system design, is
    constructed to obtain the optimum number of cooperative secondary
    users. It can be found that the selection scheme is to make a
    tradeoff between the system complexity of the cognitive radio
    network and the global sensing performance of the cooperative
    spectrum sensing.
    References | Related Articles | Metrics
    An Efficient Threshold Key-Insulated Signature Scheme
    CHEN Jian-hong (陈剑洪), LONG Yu (龙 宇), CHEN Ke-fei (陈克非) WANG Yong-tao (王永涛),LI Xiang-xue (李祥学)
    2011, 16 (6):  658-662.  doi: 10.1007/s12204-011-1207-3
    Abstract ( 1271 )  
    To tackle the key-exposure problem in signature settings,
    this paper introduces a new cryptographic primitive named threshold key-insulated
    signature (TKIS) and proposes a concrete TKIS scheme.For a TKIS system, at
    least k out of n helpers are needed to update a user's temporary private key.
    On the one hand, even if up to k-1 helpers are compromised in addition to the
    exposure of any of temporary private keys, security of the non-exposed
    periods is still assured. On the other hand, even if all the n helpers are
    compromised, we can still ensure the security of all periods as long as none
    of temporary private keys is exposed. Compared with traditional
    key-insulated signature (KIS) schemes, the proposed TKIS scheme not only
    greatly enhances the security of the system, but also provides flexibility
    and efficiency.
    References | Related Articles | Metrics
    Directed Proxy Signature in the Standard Model
    MING Yang (明 洋), WANG Yu-min (王育民)
    2011, 16 (6):  663-671.  doi: 10.1007/s12204-011-1208-2
    Abstract ( 1639 )  
     restricted verification ability.  Directed signatures
    allow only a designated verifier to check the validity of the
    signature issued to him, and at the time of trouble or if necessary,
    any third party can verify the signature with the help of the signer
    or the designated verifier. Directed signature schemes are widely
    used in situations where the receiver's privacy should be protected.
    Proxy signatures allow an entity to delegate its signing capability
    to another entity in such a way that the latter can sign message on
    behalf of the former when the former is not available. Proxy
    signature schemes have found numerous practical applications such as
    distributed systems and mobile agent applications. In this paper, we
    firstly define the notion of the directed proxy signature by
    combining the proxy signature and directed signature. Then, we
    formalize its security model and present a concrete scheme in the
    standard model. Finally, we use the techniques from provable
    security to show that the proposed scheme is unforgeable under the
    gap Diffie-Hellman assumption, and invisible under the decisional
    Diffie-Hellman assumption.
    References | Related Articles | Metrics
    Chosen Ciphertext Secure Identity-Based Broadcast Encryption in the Standard Model
    SUN Jin (孙 瑾), HU Yu-pu (胡予濮), ZHANG Le-you (张乐友)
    2011, 16 (6):  672-676.  doi: 10.1007/s12204-011-1209-1
    Abstract ( 1442 )  
     To give concurrent consideration both
    the efficiency and the security (intensity of intractable problem)
    in the standard model, a chosen ciphertext secure identity-based
    broadcast encryption is proposed. Against the chosen ciphertext
    security model, by using identity (ID) sequence and adding
    additional information in ciphertext, the self-adaptive chosen
    identity security (the full security) and the chosen ciphertext
    security are gained simultaneously. The reduction of scheme's
    security is the decisional bilinear Diffie-Hellman (BDH) intractable
    assumption, and the proof of security shows that the proposed scheme
    is indistinguishable against adaptive chosen ciphertext attacks in
    the standard model under the decisional BDH intractable assumption.
    So the security level is improved,and it is suitable for higher
    security environment.
    References | Related Articles | Metrics
    Pre-emptive Channel Borrowing and Traffic Overflowing Channel
    Allocation Scheme for Multimedia Overlay Networks
    ZHAO Fang-ming (赵方明), HANG Juan (杭 娟), HE Di (何 迪)
    2011, 16 (6):  677-686.  doi: 10.1007/s12204-011-1210-8
    Abstract ( 1121 )  
     This paper proposes a channel allocation
    scheme for multimedia wireless networks, in which a two-layer
    macro-cell or micro-cell architecture is considered. Macro-cells are
    used to access high-mobility services; while micro-cells, which are
    overlaid by the macro-cells, are used to cater low-mobility
    services. To analyze the scheme, a multidimensional Markov traffic
    model is firstly developed, in which traffic characteristic of two
    special periods of time is considered. And then, a pre-emptive
    channel-borrowing scheme combined with traffic-overflowing strategy
    for multimedia (voice, video or data) networks is proposed, in which
    handoff requests can not only borrow channels from adjacent
    homogenous cells, but also be overflowed to heterogeneous cells.
    Priority strategies are also dedicated to high-mobility services for
    they can pre-empt channels being used by low-mobility services in
    macro-cells. To meet the high quality of service (QoS) requirements
    of video services and increase the channel utilization ratio, video
    services can be transformed between real-time services and
    non-real-time services as necessary. Simulation results show that
    our schemes can decrease the blocking probabilities and improve the
    channel utilization.
    References | Related Articles | Metrics
    Model and Simulation of a New Ultra-Narrow Trigger Frequency
    Alterable Pulse Generator
    YANG Yun-feng (杨运峰), CAO Zhen-xin (曹振新), YE Zhan(叶 展), DOU Wen-bin (窦文斌), SU Hong-yan (苏宏艳)
    2011, 16 (6):  687-690.  doi: 10.1007/s12204-011-1211-7
    Abstract ( 1649 )  
     Two new kinds of ultra-narrow trigger
    frequency alterable picosecond pulse generator are presented. One
    can produce positive pulses and the other can produce negative
    pulses. The two pulse generators are subdivided into three parts:
    signal driving circuit, differentiator network and pulse shaping
    circuit. The pulse shaping circuit is made of step recovery diode
    (SRD) and short-circuit microstrip line. A positive pulse with width
    of 54 ps (50% ---50% ), rising time of 30 ps (10%  ---90%  )
    and falling time of 32 ps (90%  ---10%  ), and a negative pulse
    with width of 54 ps (50%  ---50%  ), rising time of 30 ps
    (90%  ---10%  ) and falling time of 30 ps (10%  ---90%  ) are
    achieved in simulation. All of the components are ready-made and
    inexpensive. They can be applied in ultra-wideband (UWB)
    communication system, such as transmitters and receivers.
    References | Related Articles | Metrics
    Joint User and Antenna Selection for  Multiuser MIMO Downlink with
    Block Diagonalization
    LIU Wei (刘 伟), ZOU Jun (邹 俊), LUO Han-wen (罗汉文), MA Ji-peng (马继鹏)
    2011, 16 (6):  691-695.  doi: 10.1007/s12204-011-1212-6
    Abstract ( 1403 )  
      User selection is necessary for
    multiuser multiple-input multiple-output (MIMO) downlink systems
    with block diagonalization (BD) due to the limited free spatial
    transmit dimensions. The pure user selection algorithms can be
    improved by performing receive antenna selection (RAS) to increase
    sum rate. In this paper, a joint user and antenna selection
    algorithm, which performs user selection for sum rate maximization
    in the first stage and then performs antenna selection in the second
    stage, is proposed. The antenna selection process alternately drops
    one antenna with the poorest channel quality based on maximum
    determinant ranking (MDR) from the users selected during the first
    stage and activates one antenna with the maximum norm of projected
    channel from the remaining users. Simulation results show that the
    proposed algorithm significantly outperforms the algorithm only
    performing user selection as well as the algorithm combining user
    selection with MDR receive antenna selection in terms of sum rate.
    References | Related Articles | Metrics
    Optimal Linear Phase Finite Impulse Response Band Pass   Filter Design Using Craziness
    Based Particle Swarm   Optimization Algorithm
    SANGEETA Mandal, SAKTI Prasad Ghoshal, RAJIB Kar,
    2011, 16 (6):  696-703.  doi: 10.1007/s12204-011-1213-5
    Abstract ( 2112 )  
     An efficient method is proposed for the
    design of finite impulse response (FIR) filter with arbitrary pass
    band edge, stop band edge frequencies and transition width. The
    proposed FIR band stop filter is designed using craziness based
    particle swarm optimization (CRPSO) approach. Given the filter
    specifications to be realized, the CRPSO algorithm generates a set
    of optimal filter coefficients and tries to meet the ideal frequency
    response characteristics. In this paper, for the given problem, the
    realizations of the optimal FIR band pass filters of different
    orders have been performed. The simulation results have been
    compared with those obtained by the well accepted evolutionary
    algorithms, such as Parks and McClellan algorithm (PMA), genetic
    algorithm (GA) and classical particle swarm optimization (PSO).
    Several numerical design examples justify that the proposed optimal
    filter design approach using CRPSO outperforms PMA and PSO, not only
    in the accuracy of the designed filter but also in the convergence
    speed and solution quality.
    References | Related Articles | Metrics
    Chaff Cloud Jamming Suppression Based on Wavelet Transform
    ZHAO Hai-bo (赵海波), PEI Jin-ze (裴晋泽), ZHAO Lei-ming (赵雷鸣), HU Guang-rui (胡光锐)
    2011, 16 (6):  704-707.  doi: 10.1007/s12204-011-1214-4
    Abstract ( 1243 )  
     Radar target signals and chaff cloud
    jamming signals have different characters by the wavelet transform.
    The wavelet coefficients of radar target signals are highly
    correlated with its near-and-near-scale wavelet coefficients,
    however the correlativity between the wavelet coefficients of chaff
    cloud jamming signals and its near-and-near scale wavelet
    coefficients is less significant. Based on the binary-base discrete
    wavelet transform and the correlation algorithm, the method of
    target entropy to estimate standard variance of the jamming signals
    and each scale is proposed to ensure reasonable threshold, to
    suppress chaff cloud signals and finally to reconstruct mixed
    signals by the improved spatially selective noise filtration (ISSNF)
    method. The extensive simulation results show that the proposed
    method can availably suppress chaff cloud jamming and decontaminate
    target echo.
    References | Related Articles | Metrics
    Efficient Clustering and Simulated Annealing Approach 
    for Circuit Partitioning
    SANDEEP Singh Gill, RAJEEVAN Chandel, ASHWANI Kumar Chandel
    2011, 16 (6):  708-712.  doi: 10.1007/s12204-011-1138-z
    Abstract ( 1803 )  
    Circuit net list bipartitioning using
    simulated annealing technique has been proposed in the paper. The
    method converges asymptotically and probabilistically to global
    optimization. The circuit net list is partitioned into two
    partitions such that the number of interconnections between the
    partitions is minimized. The proposed method begins with an
    innovative clustering technique to obtain a good initial solution.
    Results obtained show the versatility of the proposed method in
    solving non polynomial hard problems of circuit net list
    partitioning and show an improvement over those available in
    literature.
    References | Related Articles | Metrics
    Improved Preimage Attack on 3-Pass HAVAL
    ZHONG Jin-min (钟锦敏), LAI Xue-jia (来学嘉), DUAN Ming (段 明)
    2011, 16 (6):  713-721.  doi: 10.1007/s12204-011-1215-3
    Abstract ( 1630 )  
     HAVAL is a hash function proposed by
     Zheng et al. in 1992, including 3-, 4- and 5-pass versions.
    We improve pseudo-preimage and preimage attacks on 3-pass HAVAL at
    the complexity of 2^  172   and 2^  209.6  , respectively, as
    compared to the previous best known results: 2^  192   and 2^  225 
    by Sasaki et al. in 2008. We extend the skip interval for
    partial-patching and apply the initial structure technique to find
    the better message chunks, and combine the
    indirect-partial-matching, partial-fixing and multi-neutral-word
    partial-fixing techniques to improve the attacks based on the
    meet-in-the-middle method. These are the best pseudo-preimage and
    preimage attacks on 3-pass HAVAL.
    References | Related Articles | Metrics
    Fusion of Remote Sensing Images Based on   Nonsubsampled Contourlet Transform and Region Segmentation
    WU Yi-quan (吴一全), WU Chao (吴 超), WU Shi-hua (吴诗婳)
    2011, 16 (6):  722-727.  doi: 10.1007/s12204-011-1216-2
    Abstract ( 1662 )  
    The purpose of remote sensing images fusion is to produce a
    fused image that contains more clear, accurate and comprehensive information
    than any single image. A novel fusion method is proposed in this paper based
    on nonsubsampled contourlet transform (NSCT) and region segmentation.
    Firstly, the multispectral image is transformed to intensity-hue-saturation (IHS) system. Secondly, the panchromatic image and the component intensity of the multispectral image are
    decomposed by NSCT. Then the NSCT coefficients of high and low frequency
    subbands are fused by different rules, respectively. For the high frequency
    subbands, the fusion rules are also unalike in the smooth and edge regions.
    The two regions are segregated in the panchromatic image, and the
    segmentation is based on particle swarm optimization. Finally, the fusion
    image can be obtained by performing inverse NSCT and inverse IHS transform.
    The experimental results are evaluated by both subjective and objective
    criteria. It is shown that the proposed method can obtain superior results
    to others.
     
    References | Related Articles | Metrics
    Micro-Electro-Mechanical-Sensor Inertial Navigation    System-Assisted Global Navigation Satellite System     Receiver  Acquisition Scheme and Performance
    Evaluation
    YE Ping (叶 萍), ZHAN Xing-qun (战兴群), ZHANG Yan-hua (张炎华)
    2011, 16 (6):  728-733.  doi: 10.1007/s12204-011-1217-1
    Abstract ( 1457 )  
    When an aircraft moves under a low
    carrier-to-noise ratio (CNR) or at a high speed, increasing the
    sensitivity of global navigation satellite system (GNSS) receiver is
    a goal quite hard to achieve. A novel acquisition scheme assisted
    with micro-electro-mechanical-sensor (MEMS) inertial navigation
    system (INS) is presented to estimate the Doppler caused by user
    dynamics relative to each satellite ahead of time. Based on tightly
    coupled GNSS/INS estimation algorithm, MEMS INS Doppler error that
    can be achieved is first described. Then, by analyzing the mean
    acquisition time and signal detection probability, the MEMS
    INS-assisted acquisition capabilities in cold, warm and hot starts
    are quantitatively determined and compared with the standard GNSS
    acquisition capability. The simulations and comparisons have shown
    that: the acquisition time in cold start can be shortened by at
    least 23 s, the time in warm start can be shortened to 1 s and the
    acquisition capability is improved 95%, and the reacquisition
    time in hot start can be shortened by around 0.090 s and the
    capability can be enhanced 40%. The results demonstrate the
    validity of the novel method.
    References | Related Articles | Metrics
    Solving the Euclidean Steiner Minimum Tree Using    Cellular
    Stochastic Diffusion Search Algorithm
    ZHANG Jin (张 瑾), ZHAO Ya-liang (赵雅靓), MA Liang (马 良)
    2011, 16 (6):  734-741.  doi: 10.1007/s12204-011-1218-0
    Abstract ( 1480 )  
     The Euclidean Steiner minimum tree
    problem is a classical NP-hard combinatorial optimization problem.
    Because of the intrinsic characteristic of the hard computability,
    this problem cannot be solved accurately by efficient algorithms up
    to now. Due to the extensive applications in real world, it is quite
    important to find some heuristics for it. The stochastic diffusion
    search algorithm is a newly population-based algorithm whose
    operating mechanism is quite different from ordinary intelligent
    algorithms, so this algorithm has its own advantage in solving some
    optimization problems. This paper has carefully studied the
    stochastic diffusion search algorithm and designed a cellular
    automata stochastic diffusion search algorithm for the Euclidean
    Steiner minimum tree problem which has low time complexity.
    Practical results show that the proposed algorithm can find approving results
    in short time even for the large scale size, while exact algorithms need to cost several hours.
    References | Related Articles | Metrics
    Aero-Optical Characteristics of Supersonic Flow over   Blunt Wedge
    with Cavity Window
    LI Bo (李 波), LIU Hong (刘 洪)
    2011, 16 (6):  742-749.  doi: 10.1007/s12204-011-1219-z
    Abstract ( 1514 )  
    The optical rays that form the image of
    an object and propagate a supersonic flow over a vehicle are
    refracted by the density variations. A numerical analysis of the
    aero-optical characteristics of supersonic flow over blunt wedge
    with a cavity window is carried out. A hybrid method of Reynold
    averaged Navier-Stokes and direct simulation Monte Carlo (RANS/DSMC)
    is employed to simulate the flowfield. Refraction factor is
    introduced to evaluate the flowfield's aero-optical characteristic.
    The results show that mean flow's aero-optical effects are mainly
    caused by the shock wave, the expansion wave and the turbulent
    boundary layer. Fluctuation flow's aero-optical effects are mainly
    caused by the turbulent boundary layer and the shock wave induced by
    the cavity window. The aero-optical effects at the leading side of
    window are caused by the mean density variations, while the effects
    at the trailing side are caused by the density fluctuations.
    Different draft angles of the cavity window are investigated. The
    airborne optical devices of supersonic vehicle should be mounted in
    the middle of the cavity window with a large draft angle.
    References | Related Articles | Metrics
    Structure-Borne Sound Attenuation at Corner Interface with Dynamic Vibration Absorber Attached
    CHE Chi-dong (车驰东), CHEN Duan-shi (陈端石)
    2011, 16 (6):  750-758.  doi: 10.1007/s12204-011-1220-6
    Abstract ( 1450 )  
    Structure-borne sound attenuation at corner interface of two plates with dynamic vibration absorber attached is investigated by wave approach. Equations governing transmission and reflection coefficients are deduced by introducing some non-dimensional coefficients, which help to reveal the physical sense inside and to simplify the analysis. Numerical investigation on vibration energy transmission of bending wave is carried out as well. The results from measurement and prediction show almost the same trends in the simplified experiment. It is found that energy transmission at corner interface depends greatly on whether the dynamic vibration absorber attached acts at resonance and is relatively lower right after the nature frequency of dynamic vibration absorber. Furthermore, the dynamic vibration absorber attached provides less energy transmission of bending wave than blocking mass at the end of ``passing band''.
     
    References | Related Articles | Metrics
    Sensitivity Analysis of Thermal Properties on   Numerical Simulation
    Results of Quenching Process
    ZHOU Zhi-fang (周志方), GU Jian-feng (顾剑锋), WANG Xiao-yan (王晓燕), PAN Jian-sheng (潘健生)
    2011, 16 (6):  759-762.  doi: 10.1007/s12204-011-1221-5
    Abstract ( 1332 )  
    A three-factor three-level orthogonal test project has been designed based on the numerical simulation of a Jominy quenching process. Then the data scattering effects of thermal conductivity and enthalpy of tested steel, as well as the heat exchange coefficients of the cooling media, on the results have been studied. The results can be used as a reference for choosing the input thermal parameter in finite element simulation of quenching, and for evaluating the simulation results.
     
    References | Related Articles | Metrics