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    29 February 2012, Volume 17 Issue 1 Previous Issue    Next Issue

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    Articles
    An Improved Cyclostationary Feature Detection Based on  the Selection of
    Optimal Parameter in Cognitive Radios
    SHEN Da (沈 达), HE Di (何 迪), LI Wen-hua (李文化), LIN Ying-pei (林英沛)
    2012, 17 (1):  1-007.  doi: 10.1007/s12204-012-1222-z
    Abstract ( 1568 )  

    Abstract: Spectrum sensing is an important part of
    cognitive radio systems to find spectrum hole for transmission which
    enables cognitive radio systems coexist with the authorized radio
    systems without harmful interference. In this paper, an improved
    cyclostationary feature detection method is proposed to reduce
    computational complexity without loss of good performance based on
    the optimal parameter selection strategy for choosing detection
    parameters of cyclic frequency and lag. Taking binary phase shift
    keying (BPSK) and quadrature phase shift keying (QPSK) signals as
    examples, the theoretical analyses are presented for choosing the
    optimal parameters. Simulation results are given to certify the
    correctness of the proposed parameter selection strategy and show
    the performance of the proposed method.
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    Image Fusion Scheme Based on Nonsubsampled Contourlet and Block-Based Cosine Transform
    SONG Hao-hao (宋好好), LU Zhen (陆 臻)
    2012, 17 (1):  8-012.  doi: 10.1007/s12204-012-1223-y
    Abstract ( 1455 )  
    Abstract: A kind of nonsubsampled contourlet and
    block-based cosine transform (NSCBCT) is developed, and its
    application in image fusion is studied in this paper. The
    construction of filtering banks is based on the nonsubsampled
    contourlet transform (NSCT) and block-based discrete cosine
    transform (B-DCT). We combine NSCT and B-DCT to design filters that
    lead to NSCBCT with better singularity representation than either of
    them in isolation. A design framework based on the hybrid approach
    is proposed, which allows for the fast implementation based on NSCT
    and B-DCT respectively. In addition, a new image fusion scheme based
    on NSCBCT for multispectral and panchromatic satellite images is
    proposed. Firstly, because it adopts NSCT, the fused satellite
    images have higher spatial resolution than those based on wavelets.
    Secondly, based on the localized high frequency information provided
    by B-DCT, the proposed fusion scheme can reduce the spectral
    distortion of the fused image further. Experimental results show
    that the proposed fusion method is able to increase the spatial
    resolution and reduce the spectral distortion of the fused image at
    the same time.
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    Degradation of Selected Indoor Air Pollutants: Comparison Study of Photocatalytic, Ozone-Assisted Photocatalytic and  Amine Adsorption Processes
    ZHAO Wen-chang (赵文昌), CHENG Jin-ping(程金平), CHEN Ying (陈 颖), WANG Wen-hua (王文华)
    2012, 17 (1):  13-019.  doi: 10.1007/s12204-012-1224-x
    Abstract ( 1428 )  
    Abstract: Indoor air pollutants impact human
    health, comfort and productivity. The method of photocatalysis has
    been applied mainly in flow reactors and little information is
    available on indoor air pollutant removal in airtight reactors. In
    the paper, experiments were carried out to remove formaldehyde
    (HCHO), ammonia (NH_3) and volatile organic compounds (VOCs) in
    the airtight and ventilated chambers. Results demonstrated that
    90.4% of HCHO, 92.3% of NH_3 and 57.9% of VOCs were
    removed in the amine adsorption process, while 67.5%
    (hereinbefore, these are the mass fraction) of HCHO, 60.0% of
    NH_3, and 61.2% of VOCs were removed in the photocatalytic
    process. However, ozone-assisted photocatalytic process showed great
    potential to degrade indoor air pollutants in the ventilated
    chamber. Factors and mechanisms of the photocatalytic degradation of
    HCHO, NH_3 and VOCs were also discussed.
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    Analysis of Motion in Longitudinal Plane of Negative Buoyancy Vehicle Flying Fish II
    YAN Hui (颜 翚), GE Tong (葛 彤), YING Si-bin (应思斌), WU Chao (吴 超), YUAN Qing-qing (袁庆晴)
    2012, 17 (1):  20-024.  doi: 10.1007/s12204-012-1225-9
    Abstract ( 1624 )  
    Abstract: This article describes an experimental prototype flying fish II and builds a dynamic model that is a novel type of autonomous underwater vehicle (AUV) under the condition of negative buoyancy vehicle (NBV) without large buoyancy mechanism. Compared with the AUV Remus100, the flying fish II can cruise with double speeds within the same range and dimensions. The static stability and motion modes of flying fish II in the longitudinal plane are analyzed through the linear system theory. The flying fish II has static stability in the longitudinal plane and the motion mode is related to metacentric height.
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    A Novel Vertical Handoff Algorithm Based on Fuzzy Logic in Aid of Grey Prediction Theory in Wireless Heterogeneous Networks
    LIU Xia (刘 侠), JIANG Ling-ge (蒋铃鸽)
    2012, 17 (1):  25-030.  doi: 10.1007/s12204-011-1137-0
    Abstract ( 1409 )  
    Abstract: To coordinate the various access technologies in the 4G communication system, intelligent vertical handoff algorithms are required. This paper mainly deals with a novel vertical handoff decision algorithm based on fuzzy logic with the aid of grey theory and dynamic weights adaptation. The grey prediction theory (GPT) takes 4 sampled received signal strengths as input parameters, and calculates the predicted received signal strength in order to reduce the call dropping probability. The fuzzy logic theory based quantitative decision algorithm takes 3 quality of service (QoS) metric, received signal strength (RSS), available bandwidth (BW), and monetary cost (MC) of candidate networks as input parameters. The weight of each QoS metrics is adjusted along with the networks changing to trace the network condition. The final optimized vertical handoff decision is made by comparing the quantitative decision values of the candidate networks. Simulation results demonstrate that the proposed algorithm provides high performance in heterogeneous as well as homogeneous network environments.
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    Robust Adaptive Horizontal Vibration Isolation of Towed Seismic Streamers
    LIU Tao (刘 涛), ZHANG Wei-jing (张维竞), MA Jie (马 捷)
    2012, 17 (1):  31-039.  doi: 10.1007/s12204-012-1226-8
    Abstract ( 1185 )  
    Abstract: The horizontal vibration of towed seismic streamers is a main reason for efficiency reduction of the seismic survey and tail tangling. A vibration suppression scheme of towed seismic streamers is investigated in this paper. The towed seismic streamer is divided into two spans, a controlled span, i.e., the low tension span, and an uncontrolled span, i.e., the high tension span, by a bird. The system model includes a hyperbolic partial differential equation with variable coefficient describing the towed seismic streamers, and an ordinary differential equation describing the dynamic of bird. Robust based-model knowledge and adaptive controllers, based on the Lyapunov method, are designed to isolate the vibration of towed seismic streamers caused by the course deviations of towing vessel, the variations of towing vessel velocity and the variations of towed seismic streamer density. The robust based-model knowledge and adaptive controllers exponentially and asymptotically drive the span-towed seismic streamer displacement to zero, respectively. A finite difference scheme is used to validate the efficiency of the control law. The proposed controller can isolate effectively the disturbance originated from the towed vessel, and can provide the improved damping but not sacrifice the isolation performance. The adaptive scheme can tolerate the lack of knowledge of some uncertain parameters and can directly execute the online adjustment of the parameters. Meanwhile, the proposed control law is robust and can resist the model uncertainty due to parameter incertitude, model error and unknown disturbance and so on. The control law only includes velocity and slope, while it does not need the displacement which is difficult to measure in the practical operations. Thus it is easy to implement.
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    Evolutionary Algorithms for Solving Unconstrained Multilevel Lot-Sizing Problem with Series Structure
    HAN Yi (韩 毅), CAI Jian-hu (蔡建湖), IKOU Kaku, LI Yan-lai (李延来) CHEN Yi-zeng (陈以增), TANG Jia-fu (唐加福)
    2012, 17 (1):  39-044.  doi: 10.1007/s12204-012-1227-7
    Abstract ( 1372 )  
    Abstract: This paper presents a comparative study of evolutionary algorithms which are considered to be effective in solving the multilevel lot-sizing problem in material requirement planning (MRP) systems. Three evolutionary algorithms (simulated annealing (SA), particle swarm optimization (PSO) and genetic algorithm (GA)) are provided. For evaluating the performances of algorithms, the distribution of total cost (objective function) and the average computational time are compared. As a result, both GA and PSO have better cost performances with lower average total costs and smaller standard deviations. When the scale of the multilevel lot-sizing problem becomes larger, PSO is of a shorter computational time.
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    Enthalpy and Exergy Transfers of High Pressure Switching Expansion Reduction
    LUO Yu-xi (罗语溪), WANG Xuan-yin (王宣银), LEI Jun-bo (雷军波)
    2012, 17 (1):  45-052.  doi: 10.1007/s12204-012-1228-6
    Abstract ( 1071 )  
    Abstract: The energy balance, air internal energy, enthalpy and exergy transfers of high pressure switching expansion reduction (SER) are comparatively analyzed in this paper to give a better understanding about the exergy analysis and its difference between energy conversion analyses for the pneumatics. In SER, the exergy transfer efficiency is much lower than the enthalpy efficiency. The enthalpy efficiency is primarily related to the initial pressure of supply tanks, and the exergy efficiency is primarily related to the pressure reduction ratios. Heat transfers increase the internal energy, enthalpy and exergy of air; the influence on exergy is relatively small. The total enthalpy in SER decreases as the air temperature decreases in the expansion process of the air. And exergy loss is primarily related to the irreversible process of isenthalpic throttling but not energy conversion. Based on the analyses, to improve the exergy efficiency of the pneumatics, the pressure reduction without power output should be avoided.
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    A 38 MPa Compressor Based on Metal Hydrides
    HU Xiao-chen (胡晓晨), QI Zhao-gang (祁照岗), YANG Ming (阳 明), CHEN Jiang-ping (陈江平)
    2012, 17 (1):  53-057.  doi: 10.1007/s12204-012-1229-5
    Abstract ( 1197 )  
    Abstract: Known as one of the most promising application of metal hydride (MH), the MH compressor can afford hydrogen with high pressure and high purity. Two AB5 type multi-component hydrogen storage alloys and vanadium are studied for the purpose of high pressure compression. A compact compression system has been built. Each designed small-size reactor contains seven special stainless-steel pipes. The single stage compressor can improve the hydrogen pressure from 2 up to 35 MPa with the hydrogen desorbed per unit mass of 207.8 mL/g. The two-stage compression can output hydrogen with pressure of 38 MPa steadily in whole 5.7 mol hydrogen output flow. However, its hydrogen desorbed per unit mass was only computed to 106.9 mL/g as a result of two reactors used in the cycle and the output mass of hydrogen increased less.
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    Experimental and Stowing/Deploying Dynamical Simulation of Lenticular Carbon Fiber Reinforced Polymer Thin-Walled Tubular Space Boom
    LI Rui-xiong (李瑞雄), CHEN Wu-jun (陈务军), FU Gong-yi (付功义)
    2012, 17 (1):  58-064.  doi: 10.1007/s12204-012-1230-z
    Abstract ( 1116 )  
    Abstract: The stowing and deploying experiment was conducted for three 700 mm long thin-walled tubes, and the structural behavior characteristics parameters were measured clearly, including strain, deformation and wrapping moment. 3D finite element models (FEM) were built subsequently and explicit dynamic method was used to simulate the stowing and deploying of the lenticular carbon fiber reinforced polymer (CFRP) thin-walled tubular space boom, which was designed as four-ply (45/-45/45/-45) lay-up. The stress and energy during the wrapping process were got and compared with different wrapping angular velocity, the reasonable wrapping angular velocity and effective method were conformed, and structural behavior characteristics were obtained. The results were compared and discussed as well, and the results show that the numerical results by 0.628 rad/s velocity agree well with the measured values. In this paper, the numerical procedure and experimental results are valuable to the optimization design of CFRP thin-walled tubular space boom and future research.
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    Shape Optimization of Bow Bulbs with Minimum Wave-Making Resistance Based on Rankine Source Method
    ZHANG Bao-ji (张宝吉)
    2012, 17 (1):  65-069.  doi: 10.1007/s12204-012-1239-3
    Abstract ( 1099 )  
    Abstract: The hull form optimization concerns one of the most important applications of wave-making resistance theories. In recent years, scholars can determine the hull form by using the optimization method based on the computational fluid dynamics (CFD) and other mathematical techniques. In this paper, the hull form optimization method based on the Rankine source method and nonlinear programming (NLP) is discussed; in the optimization process, a hull form modification function is introduced to represent an improved hull surface and to generate a new smooth hull surface by changing its frame lines and bow stem profiles under the prescribed design constraints. Numerical example is given for a practical container hull form. Finally, shape optimization of bow bulls is shown for non-protruding and protruding bow bulls. This study presents a simplified and practical design method to the select frame lines of bow bulls.
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    Research on Marine Structure Inspection Support System on Mobile Device Platform
    LI Kai (李 楷), CHEN Ming (陈 明), LIN Yan (林 焰)
    2012, 17 (1):  70-075.  doi: 10.1007/s12204-012-1231-y
    Abstract ( 1118 )  
    Abstract: Ship and offshore structure often work in very severe environment. Therefore routine inspection and maintenance are essential to keep ship structure and equipment in good state, and can decrease the possibility of sea pollution and safety problems. Besides that, the activity of inspection and maintenance is also directly connected with cost control and condition assessment. Current inspection is still mainly based on paper and pen, so it is rather time-consuming for transferring inspection data from paper to computer system, and more difficult to make calculation based on the inspection records. In this paper, the concept of information integration model and inspection support system using mobile device is introduced. The structuralized data in the information integration model offer much convenience to data transferring. The inspection support system consists of one headquarter management subsystem and one inspector handling subsystem. A mechanism of data exchange between the two subsystems is developed based on standard inspection workflow.~The headquarter subsystem works on computer, and the inspector subsystem is mobile application instead of paper and pen. Versatile tests and platform experiments are carried out to demonstrate and confirm the feasibility and validity.
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    Peak Traffic Forecasting Using Nonparametric Approaches
    ZHANG Yang (张 扬), WANG Meng-ling (王梦灵)
    2012, 17 (1):  76-081.  doi: 10.1007/s12204-012-1232-x
    Abstract ( 1146 )  
    Abstract: States of traffic situations can be classified into peak and nonpeak periods. The complexity of peak traffic brings more difficulty to forecasting models. Travel time index (TTI) is a fundamental measure in transportation. How to master the characteristics and provide accurate real-time forecasts is essential to intelligent transportation systems (ITS). Cooperating with state space approach, least squares support vector machines (LS-SVMs) are investigated to solve such a practical problem in this paper. To the best of our knowledge, it is the first time to apply the technique and analyze the forecast performance in the domain. For comparison purpose, other two nonparametric predictors are selected because of their effectiveness proved in past research. Having good generalization ability and guaranteeing global minima, LS-SVMs perform better than the others. Providing sufficient improvement in stability and robustness reveals that the approach is practically promising.
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    Numerical Study of Wave Loads on a Caisson-Pile-Deck Composite Structure over Permeability Seabed
    GUO Chuan-sheng (郭传胜), ZHANG Ning-chuan (张宁川), PEI Yu-guo (裴玉国)
    2012, 17 (1):  82-090.  doi: 10.1007/s12204-012-1233-9
    Abstract ( 1319 )  
    Abstract: To get the accurate wave loads on wharf composite structure, the wave force on small-scale piles and the uplift force on lower surface of caisson must be considered. Based on the Reynolds averaged Navier-Stokes (RANS) equations, the pore media theory and the volume of fluid (VoF) method, a three-dimensional numerical model is established. The model has been developed to simulate wave interaction with a composite structure including caisson, piles and deck. The numerical results agree very well with the experimental data on total force. The spatial distributions of the non-dimensional wave height and the maximum of wave pressure on surface of composite structure are presented and discussed. The effects of relative caisson length, relative wave height and relative caisson height on horizontal wave force are given. The result indicates that the horizontal wave force achieves maximum value at the relative caisson length of 0.18 and increases linearly with the increase of the relative caisson and wave height. It is proved that the model is an accurate and efficient numerical tool to investigate different problems of wave-structure interaction.
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    Simultaneous Localization and Mapping of Autonomous Underwater Vehicle Using Looking Forward Sonar
    ZENG Wen-jing (曾文静), WAN Lei (万 磊), ZHANG Tie-dong (张铁栋), HUANG Shu-ling (黄蜀玲)
    2012, 17 (1):  91-097.  doi: 10.1007/s12204-012-1234-8
    Abstract ( 1870 )  
    Abstract: A method of underwater simultaneous localization and mapping (SLAM) based on on-board looking forward sonar is proposed. The real-time data flow is obtained to form the underwater acoustic images and these images are pre-processed and positions of objects are extracted for SLAM. Extended Kalman filter (EKF) is selected as the kernel approach to enable the underwater vehicle to construct a feature map, and the EKF can locate the underwater vehicle through the map. In order to improve the association efficiency, a novel association method based on ant colony algorithm is introduced. Results obtained on simulation data and real acoustic vision data in tank are displayed and discussed. The proposed method maintains better association efficiency and reduces navigation error, and is effective and feasible.
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    Research on Logistics Network Infrastructures Based on DEA-PCA Approach: Evidence from the Yangtze River Delta Region in China
    JU Chun-hua (琚春华), JIANG Chang-bing (蒋长兵), CHEN Ming-yao (陈明瑶)
    2012, 17 (1):  98-107.  doi: 10.1007/s12204-012-1235-7
    Abstract ( 1939 )  
    Abstract: Compared with the extensive research on logistics network infrastructures (LNIs) in the developed world, empirical research is still scarce in China. In this paper the theory of LNIs is firstly overviewed. Then a new evaluation index system for LNIs is set up which contains factors that reflect the economic development level, transportation accessibility and turnover volume of freight traffic. An empirical study is carried out by using data envelopment analysis (DEA) and principal component analysis (PCA) approach to classify LNIs into 4 clusters for 25 cities in the Yangtze River Delta Region of China. According to the characteristics of the 4 clusters, suggestions are proposed for improving their LNIs. Finally, after comparing different LNIs of 25 cities in the Yangtze River Delta Region of China, this paper proposes that different LNIs including hub, central distribution center or cross docking center, regional distribution center or distribution center should be built reasonably in order to meet the customer's requirement in the four different cluster cities.
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    Nonlinear Analyses of Exchange Rates of Six Emerging Markets
    LEI Qiang (雷 强), PAN Ying-li (潘英丽)
    2012, 17 (1):  108-113.  doi: 10.1007/s12204-012-1236-6
    Abstract ( 1117 )  
    Abstract: This paper presents some empirical evidences on the presence of nonlinearity of exchange rates of six emerging markets by using Brock-Dechert-Scheinkman (BDS) test and Volterra-Wiener-Korenberg (VWK) model, respectively. The nonlinear dependences are found in the exchange rates of six emerging markets. Furthermore, this paper applies the VWK model with surrogate data method to detect if their nonlinear dependences are deterministic or not. The results show that the above exchange rates are deterministic and nonlinear time series. These imply that the exchange rate markets do not conform to the requirements of the random walk hypothesis. Therefore, the nonlinear dynamic model should be used to analyze the exchange rates.
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    Segmented Dynamic Optimization Model for Asset-Liability Management of Commercial Banks and Its Applications
    YANG Wen-ze (杨文泽), XU Xiao-ming (许晓鸣), CAI Yun-ze (蔡云泽)
    2012, 17 (1):  114-120.  doi: 10.1007/s12204-012-1237-5
    Abstract ( 1624 )  
    Abstract: Asset-liability management is the core business of commercial banks. Effective method of asset-liability management is a continuously exploring topic in the academic and practical fields. According to the operational characteristics of commercial banks, this paper addresses a segmented dynamic optimization model under the perspective of the regulatory environment for China commercial banks. The model can perform segmented sliding optimization and correct control variables to make optimal decision with the changes in situations for a certain future time.
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    Preliminary Characteristic of Alginate, Heparin-Chitosan-Alginate, Heparin Microencapsulated Hepatocytes System
    YU Song-lin (余松林), HAN Bao-san (韩宝三), CUI Long (崔 龙), DONG Ya-dong (董亚东) , WANG Jia-xiang (王加祥), PENG Cheng-hong (彭承宏)
    2012, 17 (1):  121-128.  doi: 10.1007/s12204-012-1238-4
    Abstract ( 1174 )  
    Abstract: Alginate, low mole mass heparin-chitosan-alginate, low mole mass heparin microcapsules (ALCAL) with good mechanical stability were made from the high voltage pulsing microcapsule shaping device. ALCAL was made of low-mole-mass heparin (LMWH), alginate (ALG) and chitosan (CS) by supramolecular layer upon layer self-assembled technique. It was found from the microscopic observation that the microcapsules had smooth surface and a porous structure with interconnected pores. The results of the permeability experiment of microcapsules using fluorescein isothiocyanate-bovine serum albumin (FITC-BSA) and fluorescein isothiocyanate-immunoglobulin G (FITC-IgG) showed that the ALCAL membrane could provide cell immuno-isolation; meanwhile, the ALCAL membrane had good biocompatibility. The potential of ALCAL microcapsules for the encapsulation of liver cells had been investigated and showed that the ALCAL membrane supports the survival, proliferation and protein secretion on encapsulating hepatocytes. The ALCAL microcapsule had several advantages compared to more widely used alginate-chitosan-alginate (ACA) microcapsules for the application of cell therapy.
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