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Digital broadcast channel estimation with compressive sensing 被引量:1
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作者 戚晨皓 吴乐南 《Journal of Southeast University(English Edition)》 EI CAS 2010年第3期389-393,共5页
In order to reduce the pilot number and improve spectral efficiency, recently emerged compressive sensing (CS) is applied to the digital broadcast channel estimation. According to the six channel profiles of the Eur... In order to reduce the pilot number and improve spectral efficiency, recently emerged compressive sensing (CS) is applied to the digital broadcast channel estimation. According to the six channel profiles of the European Telecommunication Standards Institute(ETSI) digital radio mondiale (DRM) standard, the subspace pursuit (SP) algorithm is employed for delay spread and attenuation estimation of each path in the case where the channel profile is identified and the multipath number is known. The stop condition for SP is that the sparsity of the estimation equals the multipath number. For the case where the multipath number is unknown, the orthogonal matching pursuit (OMP) algorithm is employed for channel estimation, while the stop condition is that the estimation achieves the noise variance. Simulation results show that with the same number of pilots, CS algorithms outperform the traditional cubic-spline-interpolation-based least squares (LS) channel estimation. SP is also demonstrated to be better than OMP when the multipath number is known as a priori. 展开更多
关键词 channel estimation compressive sensing (CS) digital radio mondiale (DRM) orthogonal frequency division multiplexing (OFDM)
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New signature scheme based on two cryptographic assumptions 被引量:2
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作者 郑明辉 崔国华 《Journal of Southeast University(English Edition)》 EI CAS 2007年第3期461-464,共4页
In order to improve the security of the signature scheme, a digital signature based on two hard-solved problems is proposed. The discrete logarithm problem and the factoring problem are two well known hard- solved mat... In order to improve the security of the signature scheme, a digital signature based on two hard-solved problems is proposed. The discrete logarithm problem and the factoring problem are two well known hard- solved mathematical problems. Combining the E1Gamal scheme based on the discrete logarithm problem and the OSS scheme based on the factoring problem, a digital signature scheme based on these two cryptographic assumptions is proposed. The security of the proposed scheme is based on the difficulties of simultaneously solving the factoring problem and the discrete logarithm problem. So the signature scheme will be still secure under the situation that any one of the two hard-problems is solved. Compared with previous schemes, the proposed scheme is more efficient in terms of space storage, signature length and computation complexities. 展开更多
关键词 digital signature SECURITY factoring problem discrete logarithm problem
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Analysis of geophone properties effects for land seismic data
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作者 李桂林 陈高 钟俊义 《Applied Geophysics》 SCIE CSCD 2009年第1期93-101,104,共10页
The properties of the seismic geophones are important factors for high-resolution seismic exploration and have a great influence on data quality. For this reason, we have tested three kinds of geophones currently used... The properties of the seismic geophones are important factors for high-resolution seismic exploration and have a great influence on data quality. For this reason, we have tested three kinds of geophones currently used in several regions with different geological features: desert, saline-alkali farmland, and carbonate areas in mountainous regions in order to test their property indexes. Based on the geophone vibration equation and from the property index effects ofgeophone and the connection of the geophones on seismic data, we analyzed seismic data quality acquired inthe tested regions and suggest that suitable geophone property indexes, reasonable choice of geophone types, and the suitable geophone connection can enhance the signal/noise ratio of seismic data. 展开更多
关键词 Property index GEOPHONE RESOLUTION natural frequency signal/noise ratio
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A 16bit 96kHz Chopper-Stabilized Sigma-Delta ADC 被引量:1
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作者 曹楹 任腾龙 洪志良 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2007年第8期1204-1210,共7页
A 16bit sigma-delta audio analog-to-digital converter is developed.It consists of an analog modulator and a digital decimator.A standard 2-order single-loop architecture is employed in the modulator.Chopper stabilizat... A 16bit sigma-delta audio analog-to-digital converter is developed.It consists of an analog modulator and a digital decimator.A standard 2-order single-loop architecture is employed in the modulator.Chopper stabilization is applied to the first integrator to eliminate the 1/f noise.A low-power,area-efficient decimator is used,which includes a poly-phase comb-filter and a wave-digital-filter.The converter achieves a 92dB dynamic range over the 96kHz audio band.This single chip occupies 2.68mm2 in a 0.18μm six-metal CMOS process and dissipates only 15.5mW power. 展开更多
关键词 sigma-delta modulation chopper stabilize decimator poly phase wave digital filter on-chip noise
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Effect of pre-tensioned rock bolts on stress redistribution around a roadway—insight from numerical modeling 被引量:12
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作者 GAO Fu-qiang KANG Hong-pu 《Journal of China University of Mining and Technology》 EI 2008年第4期509-515,共7页
The importance of the pre-tensioned force of rock bolts has been recognized by more and more researchers. To investi- gate the effect of pre-tensioned rock bolts on stress redistribution around roadways, a numerical a... The importance of the pre-tensioned force of rock bolts has been recognized by more and more researchers. To investi- gate the effect of pre-tensioned rock bolts on stress redistribution around roadways, a numerical analysis was carried out using FLAC3D and a special post-process methodology, using surfer, is proposed to process the numerical simulation results. The results indicate that pre-tensioned rock bolts have a significant effect on stress redistribution around a roadway. In the roof, pre-tensioned rock bolts greatly increase vertical stress; as a result, the strength of the rock mass increased significantly which results in a greater capacity of bearing a large horizontal stress. The horizontal stress decreases in the upper section of the roof, indicating that pre-tensioned rock bolts significantly reduce the coefficient and the size of the region concentration of horizontal stress. At the lat- eral side, pre-tensioned rock bolts greatly increase the horizontal stress; therefore, the rock mass strength significantly increases which results also in a greater capacity of bearing a large vertical stress. The greater the size of pre-tensioned force, the larger the region of stress redistribution around a roadway is affected and the higher the size of the stress on the roadway surface the more the rock mass strength increases. 展开更多
关键词 pre-tensioned rock bolts stress redistribution numerical simulation
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A LINEAR APPROACH TO METRIC CIRCUMFERENCE COMPUTATIO FOR DIGITIZED CONVEX SHAPES 被引量:3
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作者 Chen Ken Zhao Pan Yang Rener 《Journal of Electronics(China)》 2008年第4期572-575,共4页
Metric measurement of digitized shapes is commonly applied in optical measuring systems.In this letter,three shape-related factors defined by the authors are used in the construction of amultiple linear regression mod... Metric measurement of digitized shapes is commonly applied in optical measuring systems.In this letter,three shape-related factors defined by the authors are used in the construction of amultiple linear regression model which is utilized to compute the circumference of the convex shapes inmillimeter unit.The model is first built upon the relationship hypothesis and then its adequacy ismathematically validated.The results of applying the developed model to the given number of convexshapes in a finite circumferential length range suggest that,in terms of percent error,the model pre-cision is to satisfaction by being within±4%.The test also shows the model’s robustness against theshape’s orientation anisotropy. 展开更多
关键词 Metric measurement Circumference computation Digital image analysis Modeling
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Stability analysis unit and spatial distribution pattern of the terrain texture in the northern Shaanxi Loess Plateau 被引量:4
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作者 DING Hu NA Jia-ming +2 位作者 HUANG Xiao-li TANG Guo-an LIU Kai 《Journal of Mountain Science》 SCIE CSCD 2018年第3期577-589,共13页
Terrain texture analysis is an important method of digital terrain analysis in quantitative geomorphological research and in the exploration of the spatial heterogeneity and autocorrelation of terrain features. Howeve... Terrain texture analysis is an important method of digital terrain analysis in quantitative geomorphological research and in the exploration of the spatial heterogeneity and autocorrelation of terrain features. However, a major issue often neglected in previous studies is the calculation unit of the terrain texture, that is, the stability analysis unit. As the test size increases, the derived terrain textures become increasingly similar so that their differences can be ignored. The test size of terrain texture is defined as the stability analysis unit. This study randomly selected 48 areas within the Loess Plateau in northern Shaanxi in China as the study sites and used the gray level co-occurrence matrix to calculate the terrain texture. The stability analysis unit of the terrain texture was then extracted, and its spatial distribution pattern in the Loess Plateau was studiedusing spatial interpolation method. Four terrain texture metrics, i.e., homogeneity, energy, correlation, and contrast, were extracted on the basis of the stability analysis unit, and the spatial variation patterns of these parameters were studied. Results showed that the spatial distribution pattern and the terrain texture metrics reflected a trend of high–low–high from north to south, which correlated with the spatial distribution of the landforms at the Loess Plateau. In addition, the terrain texture measures was significantly correlated with the terrain factors of gully density and slope, and this relationship showed that terrain texture measures based on the stability analysis unit could reflect the basic characteristics of terrain morphology. The stability analysis unit provided a reasonable analytical scale for terrain texture analysis and could be used as a measure of the regional topography to accurately describe basic terrain characteristics. 展开更多
关键词 Digital terrain analysis Terrain texture Stability analysis unit Spatial distribution Loess Plateau
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Numerical analysis of acoustic band gaps in two-dimensional periodic materials 被引量:4
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作者 ZHAO Yan-cheng ZHAO Fang YUAN Li-bo 《Journal of Marine Science and Application》 2005年第4期65-69,共5页
Using the plane-wave expansion (PWE)method , the band gaps of the two-dimension phononic crystals composed of square, triangle and honeycomb arrays aluminum cylinders in the air are calculated numerically. The band st... Using the plane-wave expansion (PWE)method , the band gaps of the two-dimension phononic crystals composed of square, triangle and honeycomb arrays aluminum cylinders in the air are calculated numerically. The band structures of three lattices were compared and analyzed. It is concluded that the band-gap of honeycomb lattices is located at lower frequency fields, compared with square and triangle lattices. When the filling fraction is between 0.091 and 0.6046, the honeycomb lattices have larger band gaps and gain an advantage over square and triangle lattices. In addition, the gap map is introduced to illustrate the influences of filling fraction on the number, the relative width and the limit frequency of the band-gap. 展开更多
关键词 phononic crystal acoustic: band gap plane-wave expansion (PWE) method lattice constant
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Model heat source using actual distribution of laser power density for simulation of laser processing 被引量:2
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作者 WANG Gen-wang DING Ye +2 位作者 GUAN Yan-chao WANG Yang YANG Li-jun 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第10期3277-3293,共17页
The model of heat source(MHS) which reflects the thermal interaction between materials and laser during processing determines the accuracy of simulation results. To acquire desirable simulations results, although vari... The model of heat source(MHS) which reflects the thermal interaction between materials and laser during processing determines the accuracy of simulation results. To acquire desirable simulations results, although various modifications of heat sources in the aspect of absorption process of laser by materials have been purposed, the distribution of laser power density(DLPD) in MHS is still modeled theoretically. However, in the actual situations of laser processing, the DLPD is definitely different from the ideal models. So, it is indispensable to build MHS using actual DLPD to improve the accuracy of simulation results. Besides, an automatic modeling method will be benefit to simplify the tedious pre-processing of simulations. This paper presents a modeling method and corresponding algorithm to model heat source using measured DLPD. This algorithm automatically processes original data to get modeling parameters and provides a step MHS combining with absorption models. Simulations and experiments of heat transfer in steel plates irradiated by laser prove the mothed and the step MHS. Moreover, the investigations of laser induced thermal-crack propagation in glass highlight the signification of modeling heat source based on actual DLPD and demonstrate the enormous application of this method in the simulation of laser processing. 展开更多
关键词 heat source laser processing distribution of power density digital images processing heat transfer
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Degradation of a discrete infilled joint shear strength subjected to repeated blast-induced vibrations 被引量:2
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作者 Siamaki Ali Esmaieli Kamran Mohanty Bibhu 《International Journal of Mining Science and Technology》 EI CSCD 2018年第4期560-570,共11页
This paper presents the results of a series of numerical modeling experiments aimed at quantifying blast- induced degradation of shear strength of discontinuities. Near-field vibration history of a single-row pro- duc... This paper presents the results of a series of numerical modeling experiments aimed at quantifying blast- induced degradation of shear strength of discontinuities. Near-field vibration history of a single-row pro- duction blast in a. limestone quarry was used as input to the nu .merical model. For this. purpose, two rock blocks, representing a stiff massive sulfide rock and a weaker limestone rock, were simulated using the 2D Particle Flow Code (PFC2D). Rock mass conta!ning a single inclined joint was modeled as Mohr- Coulomb. The results show that the crack generation rate is increased in both samples after repetitive vibration loading. Joint shear strength degradation rate in !he stiffer massive sulfide rock sample is higher than the softer limestone rock, which is attributed to the higher seismic impedance mismatch. The results show that even low-amplitude blasting vibrations (〈80 mm/s), when repeated as in multi-hole blasts, can significantly degrade joint shear strength in the nearby pit walls. 展开更多
关键词 BLASTING Vibration PFC2D DISCONTINUITY Rock DEGRADATION
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Numerical analysis of factors affecting the range of heat transfer in earth surrounding three subways 被引量:13
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作者 HU Zeng-hui LI Xiao-zhao ZHAO Xiao-bao XIAO Lin WU Wei 《Journal of China University of Mining and Technology》 EI 2008年第1期67-71,共5页
In order to examine the factors which affect the range of heat transfer in earth surrounding subways, FLAC3D was adopted in this study to analyze these factors, under different conditions, in a systematic manner. When... In order to examine the factors which affect the range of heat transfer in earth surrounding subways, FLAC3D was adopted in this study to analyze these factors, under different conditions, in a systematic manner. When we compare these numerical tests, the results show that the main factors, affecting the heat transfer range are the thermal properties of the surrounding earth, the initial ground temperature and the temperature in the tunnel. The heat transfer coefficient between air and linings has little effect on the temperature distribution around the tunnel. The current results can provide a reference for improving the thermal environment in subways and optimizing the design of subwav ventilation and air conditioning. 展开更多
关键词 earth surrounding subways range of heat transfer factors affecting heat transfer numerical analysis
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Drainage Network and Lineament Analysis:An Approach for Potwar Plateau(Northern Pakistan) 被引量:2
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作者 Faisal SHAHZAD Syed Amer MAHMOOD Richard GLOAGUEN 《Journal of Mountain Science》 SCIE CSCD 2009年第1期14-24,共11页
Drainage responds rapidly to tectonic changes and thus it is a potential parameter for teetonogeomorphological analysis. Drainage network of Potwar is a good geological record of movement, displacements, regional upli... Drainage responds rapidly to tectonic changes and thus it is a potential parameter for teetonogeomorphological analysis. Drainage network of Potwar is a good geological record of movement, displacements, regional uplifts and erosion of the tectonic units. This study focuses on utilizing drainage network extracted from Shuttle Radar Digital Elevation Data (SRTM-DEM) in order to constrain the structure of the Potwar Plateau. SWAN syncline divides Potwar into northern Potwar deformed zone (NPDZ) and southern Potwar platform zone (SPPZ). We extracted the drainage network from DEM and analyzed 112 streams using stream power law. Spatial distribution of concavity and steepness indices were used to prepare uplift rate map for the area. DEM was further utilized to extract lineaments to study the mutual relationship between lineaments and drainage patterns. We compared the local correlation between the extracted lineaments and drainage network of the area that gives us quantitative information and shows promising prospects. The streams in the NPDZ indicate high steepness values as compared to the streams in the SPPZ. The spatial distribution of geomorphic parameters distinctive deformation and uplift rates suggest the among eastern, central and western parts. The local correlation between drainage network and lineaments from DEM is strongly positive in the area within I km of radius. 展开更多
关键词 Drainage network LINEAMENTS streamprofile analysis uplift rate local correlation
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Numerical Analysis of Structural Progressive Collapse to Blast Loads 被引量:6
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作者 HAO Hong WU Chengqing +1 位作者 LI Zhongxian ABDULLAH A K 《Transactions of Tianjin University》 EI CAS 2006年第B09期31-34,共4页
After the progressive collapse of Ronan Point apartment in UK in 1968, intensive research effort had been spent on developing guidelines for design of new or strengthening the existing structures to prevent progressiv... After the progressive collapse of Ronan Point apartment in UK in 1968, intensive research effort had been spent on developing guidelines for design of new or strengthening the existing structures to prevent progressive collapse. However, only very few building design codes provide some rather general guidance, no detailed design requirement is given. Progressive collapse of the Alfred P. Murrah Federal building in Oklahoma City and the World Trade Centre (WTC) sparked again tremendous research interest on progressive collapse of structures. Recently, US Department of Defence (DoD) and US General Service Administration (GSA) issued guidelines for structure progressive collapse analysis. These two guidelines are most commonly used, but their accuracy is not known. This paper presents numerical analysis of progressive collapse of an example frame structure to blast loads. The DoD and GSA procedures are also used to analyse the same example structure. Numerical results are compared and discussed. The accuracy and the applicability of the two design guidelines are evaluated. 展开更多
关键词 progressive collapse blast loads damage mechanics NUMERICAL
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Segments-based progressive TIN densification filter for DTM generation from airborne LIDAR data 被引量:1
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作者 许颖 Qiu Zhiwei Yue Dongjie 《High Technology Letters》 EI CAS 2017年第1期16-22,共7页
Airborne light detection and ranging( LIDAR) has revolutionized conventional methods for digital terrain models( DTMs) acquisition. Ground filtering for airborne LIDAR is one of the core steps taken to obtain a high q... Airborne light detection and ranging( LIDAR) has revolutionized conventional methods for digital terrain models( DTMs) acquisition. Ground filtering for airborne LIDAR is one of the core steps taken to obtain a high quality DTM. This paper presents a segments-based progressive TIN( triangulated irregular network) densification( SPTD) filter that can automatically separate ground points from non-ground points. The SPTD method is composed of two key steps: point cloud segmentation and clustering by iterative judgement. The clustering method uses the dual distance to obtain a set of seed points as a coarse spatial clustering process. Then the rest of the valid point clouds are classified iteratively. Finally,the datasets provided by ISPRS are utilized to test the filtering performance.In comparison with the commercial software Terra Solid,the experimental results show that the SPTD method in this paper can avoid single threshold restrictions. The expected accuracy of ground point determination is capable of producing reliable DTMs in the discontinuous areas. 展开更多
关键词 airborne light detection and ranging (LIDAR) point cloud ground filtering tri-angulated irregular network (TIN) digital terrain models (DTMs)
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Stability influence factors analysis and construction of a deep beam anchorage structure in roadway roof 被引量:8
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作者 Xie Shengrong Gao Mingming +4 位作者 Chen Dongdong Sun Yanding Pan Hao Su Hai Lan Shizhong 《International Journal of Mining Science and Technology》 EI CSCD 2018年第3期445-451,共7页
Deep beam anchorage structures based on spatial distribution analysis of the cable prestressed field have been proposed for roadway roof support, Stability and other factors that influence deep beam structures are stu... Deep beam anchorage structures based on spatial distribution analysis of the cable prestressed field have been proposed for roadway roof support, Stability and other factors that influence deep beam structures are studied in this paper using mechanical calculations, numerical analysis and field measurements, A mechanical model of deep beam structure subjected to multiple loading is established, including analysis of roof support in the return airway of S1203 working face in the Yuwu coal mine, China, The expression of maximum shear stress in the deep beam structure is deduced according to the stress superposition criterion, It is found that the primary factors affecting deep beam structure stability are deep beam thickness, cable pre-tension and cable spacing, The variation of maximum shear stress distribution and prestressed field diffusion effects according to various factors are analyzed using Matlah and FLAC3DTM software, and practical support parameters of the S1203 return airway roof are determined, According to the observations of rock pressure, there is no evidence of roof separation, and the maximum values of roof subsidence and convergence of wall rock are 72 and 48 mm, respectively, The results show that the proposed roof support design with a deep beam structure is feasible and achieves effective control of the roadway roof, 展开更多
关键词 Support structure Deep beam Maximum shear stress Influencing factors Stability control Roadway roof
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Key technologies for the novel distributed numerical control integrated system 被引量:1
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作者 TAOGuibao LIUFei WANGShilong 《Journal of Chongqing University》 CAS 2004年第1期1-5,共5页
A novel distributed numerical control (DNC) integrated system based on plug-in software technology is proposed. It connects new or old numerical control (NC) machine tools which have inhomogeneous numerical control sy... A novel distributed numerical control (DNC) integrated system based on plug-in software technology is proposed. It connects new or old numerical control (NC) machine tools which have inhomogeneous numerical control systems with CAD/CAM system by CANbus network. A DNC computer is able to control 15 sets of NC machine tools reliably at the same time. The novel DNC system increases the efficiency of machine tools and improve the production management level by realizing non-paper production, agile manufacturing, networked manufacturing and so on in the near future. Key technologies to construct the novel DNC integrated system include the integration of inhomogeneous numerical control systems, NC program restart, and algorithm for communication competition. Such system has demonstrated successful applications in some corporations that have acquired good economic benefits and social effects. 展开更多
关键词 COMMUNICATION distributed numerical control CANBUS plug-in software program restart integrated system
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DPLL implementation in carrier acquisition and tracking for burst DS-CDMA receivers 被引量:3
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作者 管云峰 张朝阳 赖利峰 《Journal of Zhejiang University Science》 EI CSCD 2003年第5期526-531,共6页
This paper presents the architectures, algorithms, and implementation considerations of the digital phase locked loop (DPLL) used for burst-mode packet DS-CDMA receivers. As we know, carrier offset is a rather challen... This paper presents the architectures, algorithms, and implementation considerations of the digital phase locked loop (DPLL) used for burst-mode packet DS-CDMA receivers. As we know, carrier offset is a rather challenging problem in CDMA system. According to different applications, different DPLL forms should be adopted to correct different maximum carrier offset in CDMA systems. One classical DPLL and two novel DPLL forms are discussed in the paper. The acquisition range of carrier offset can be widened by using the two novel DPLL forms without any performance degradation such as longer acquisition time or larger variance of the phase error. The maximum acquisition range is 1/(4T), where T is the symbol period. The design can be implemented by FPGA directly. 展开更多
关键词 CDMA Digital phase locked loop(DPLL) Carrier frequenc y offset
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Steady State Analysis of Towed Marine Cables 被引量:7
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作者 王飞 黄国樑 邓德衡 《Journal of Shanghai Jiaotong university(Science)》 EI 2008年第2期239-244,共6页
Efficient numerical schemes were presented for the steady state solutions of towed marine cables. For most of towed systems,the steady state problem can be resolved into two-point boundary-value problem,or initial val... Efficient numerical schemes were presented for the steady state solutions of towed marine cables. For most of towed systems,the steady state problem can be resolved into two-point boundary-value problem,or initial value problem in some special cases where the initial values are available directly.A new technique was proposed and attempted to solve the two-point boundary-value problem rather than the conventional shooting method due to its algorithm complexity and low efficiency.First,the boundary conditions are transformed into a set of nonlinear governing equations about the initial values,then bisection method is employed to solve these nonlinear equations with the aid of 4th order Runge-Kutta method.In common sense,non-uniform (sheared) current is assumed,which varies in magnitude and direction with depth.The schemes are validated through the DE Zoysa's example,then several numerical examples are also presented to illustrate the numerical schemes. 展开更多
关键词 towed cable nested bisection method Runge-Kutta method non-uniform current numerical simulation
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Optimized staggered-grid finite-difference operators using window functions 被引量:6
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作者 Ren Ying-Jun Huang Jian-Ping +3 位作者 Yong Peng Liu Meng-Li Cui Chao Yang Ming-Wei 《Applied Geophysics》 SCIE CSCD 2018年第2期253-260,363,共9页
The staggered-grid finite-difference (SGFD) method has been widely used in seismic forward modeling. The precision of the forward modeling results directly affects the results of the subsequent seismic inversion and... The staggered-grid finite-difference (SGFD) method has been widely used in seismic forward modeling. The precision of the forward modeling results directly affects the results of the subsequent seismic inversion and migration. Numerical dispersion is one of the problems in this method. The window function method can reduce dispersion by replacing the finite-difference operators with window operators, obtained by truncating the spatial convolution series of the pseudospectral method. Although the window operators have high precision in the low-wavenumber domain, their precision decreases rapidly in the high-wavenumber domain. We develop a least squares optimization method to enhance the precision of operators obtained by the window function method. We transform the SGFD problem into a least squares problem and find the best solution iteratively. The window operator is chosen as the initial value and the optimized domain is set by the error threshold. The conjugate gradient method is also adopted to increase the stability of the solution. Approximation error analysis and numerical simulation results suggest that the proposed method increases the precision of the window function operators and decreases the numerical dispersion. 展开更多
关键词 Staggered-grid finite-difference operator window function least squares numerical dispersion
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Numerical Analysis of Quality Inspection of Anchorage System 被引量:1
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作者 张永兴 《Journal of Chongqing University》 CAS 2002年第1期42-46,共5页
Sonoprobe method has been applied in non-destructive inspection of anchorage project. The fundament is that dynamic transient excitation causes the elastic vibration of an anchor bar, and flaws can be estimated or ded... Sonoprobe method has been applied in non-destructive inspection of anchorage project. The fundament is that dynamic transient excitation causes the elastic vibration of an anchor bar, and flaws can be estimated or deduced by determining transient response of the anchor bar. FEA numeric solution of hyperbolic equation indicates that deductions must comply with acoustic parameters such as velocity of sound, vibration range, wave shape etc when inspecting interior flaws in the grout of an anchor bar. Based on wavelet packet analysis, the energy eigenvector is a flaw vector, which could be regarded as the basis in the nondestructive inspection of anchors. As a non-linear dynamical system, artifical neural networks dealing with quality inspection of gray system have been proved efficient. 展开更多
关键词 Anchor bar Hyperbolic equation Quality inspection WAVELET
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