Journal of University of Chinese Academy of Sciences

Parametrization of a rational developable surface using the μ-basis

CHEN Xiao-Hua, CHEN Yu-Fu, SHEN Li-Yong

2012, (3): 289-293. DOI: 10.7523/j.issn.2095-6134.2012.3.001

Finding parametrization of a given curve or surface is an essential problem in CAGD and CG. It is still open to design an algorithm for a general given curve or surface. In this paper, we focus on rational developable surfaces which are widely used in manufacturing.

Contact process on planar polygon mesh

WANG Shi-Mo

2012, (3): 294-299. DOI: 10.7523/j.issn.2095-6134.2012.3.002

Abstract ( 1217 ) PDF (KB) ( 1 )

We have studied the contact process on planar polygon mesh and drawn two conclusions. The first is that the contact process on planar polygon mesh does exist and the second is that the critical value of the planar triangle mesh is not greater than that of the planar hexagonal mesh.

Transmission of membership function under fuzzy mapping

FU Xiao-Yan, SHEN Ji-Hong

2012, (3): 300-306. DOI: 10.7523/j.issn.2095-6134.2012.3.003

Abstract ( 970 ) PDF (KB) ( 4 )

When the fuzzy inverse mapping is one-to-many and the fuzzy mapping is simple function, an algorithm to calculate membership function is given for improving the transmission of fuzziness. Under certain assumptions, we propose the transmission theorem of fuzziness of general multivariable function, and the proof is given. Using the calculation formula of marginal probability for reference, we show how to calculate one single variable membership function when the multivariable membership function is given, and the proof is also given.

Parametric finite element analysis of effective pile-length in super-long and large-diameter pile groups

CHEN Pei-Zhen, LUAN Mao-Tian, LUO Qiang

2012, (3): 307-311. DOI: 10.7523/j.issn.2095-6134.2012.3.004

Abstract ( 960 ) PDF (KB) ( 1 )

Based on the framework of FEM software ABAUQS, the three-dimensional numerical analysis for effective length of super-long and large-diameter pile groups is provided. For the pile groups of different arrangements under vertical loading, the effective pile-length was analyzed with the method of bearing capacity control. The results show that the effective pile-length increases with pile number while decreases with the space between piles. The corresponding bearing capacity decreases with pile number while the space between piles has little effect on the corresponding bearing capacity.

Molecular dynamics simulations for separation of H₂/N₂ by porous graphene

DU Huai-Liang, LI Xiao-Yi

2012, (3): 312-315. DOI: 10.7523/j.issn.2095-6134.2012.3.005

Abstract ( 1676 ) PDF (KB) ( 3 )

We designed a series of porous graphene by drilling different numbers of carbon atom. Molecular dynamics simulations indicate that hydrogen and nitrogen could be separated effectively by porous graphene. The selectivity of hydrogen and nitrogen achieves 100% when the pore size is 0.3725 nm with ten atoms dug. Porous graphene is expected to have potential applications in gas separation and purification.

Cloning and expression of PaOPT in Phytolacca americana

JIN Li, ZHENG Hong-Chun, CHAI Tuan-Yao

2012, (3): 316-323. DOI: 10.7523/j.issn.2095-6134.2012.3.006

Abstract ( 1167 ) PDF (KB) ( 2 )

An oligopeptide transporter gene was isolated from Cd-treated leaf tissue of Phytolacca americana by SSH method, designated by PaOPT (GenBank accession No. HQ647015). The full length of this gene has been cloned by race-PCR technique. Moreover, the evolution of PaOPT in OPT family and the expression profiles during seed germination period was investigated. Our study indicates that PaOPT belongs to the OPT3 family. The results of real-time quantitative PCR show that PaOPT may be a seed-specific expression gene. Further investigation of the function and localization of PaOPT will be favorable for understanding of plant growth and development.

Comparative study of cytotoxicity of winter and summer PM₁₀ and PM_2.5 in A549 cells

HE Qing, DING Wen-Jun, RUI Wei, ZHANG Fang

2012, (3): 324-331. DOI: 10.7523/j.issn.2095-6134.2012.3.007

Abstract ( 1131 ) PDF (KB) ( 2 )

Effects of winter and summer PM₁₀ and PM_2.5 collected at Beijing on the cell viability and reactive oxygen species (ROS) generation in human lung epithelia cells (A549) were investigated. We have found that cytotoxicity of summer PM is higher than that of winter PM. Transition metal elements, except Cr and Ni, have positive associations with toxic effects in A549 cells. These results suggest that transition metals in particulate matter (PM) may have the toxic effects in vitro.

Spatiotemporal evolution of difference in oasis city development in Xinjiang

DONG Wen, YANG Yu, LEI Jun

2012, (3): 332-338. DOI: 10.7523/j.issn.2095-6134.2012.3.008

Abstract ( 1249 ) PDF (KB) ( 4 )

We analyze the spatial-temporal evolution of oasis cities in Xinjiang. The results show that the urban primacy index has been increasing since 1975, especially that of Urumqi; polarization of central cities is obvious and urbanization and regional integration have been in sync; and the quantity, dimensions, and levels of the cities in North Xinjiang are greater than in the other regions of Xinjiang and the urban distribution has been substantially unbalanced. The main reasons for the urban geography in Xinjiang include distinctive characteristics of physical geography, history, economy, population, traffic-oriented urban development model, and administrative regime.

Dynamic mechanism of spatiotemporal change in economic growth in Beijing-Tianjin-Hebei metropolitan region

MA Guo-Xia, TIAN Yu-Jun

2012, (3): 339-345. DOI: 10.7523/j.issn.2095-6134.2012.3.009

Abstract ( 1053 ) PDF (KB) ( 2 )

Using the spatiotemporal diagnosis model, we analyzed mechanism of regional economic growth in Beijing-Tianjin-Hebei metropolitan region from 1993 to 2007. Some conclusions are drawn as follows. First, technology is the engine of economic growth in this region. Secondly, investment and consumption demands are important factors in economic development of this region. Thirdly, spatial interaction has gradually increasing trend in this region.

Study of structural features of industrial pollutants in the Songhua River basin in Jilin province

YANG Li-Hua, TONG Lian-Jun

2012, (3): 346-351. DOI: 10.7523/j.issn.2095-6134.2012.3.010

Abstract ( 1113 ) PDF (KB) ( 2 )

Using the shift-share deviation method we analyze interannual variations of the main pollutants in assess type, competitiveness, and structure characteristics. The results could be summarized as follows:1)emissions changed slightly and annual average growth rate was 0.4%;2)the pollution intensity decreased; and 3)in the four sample cities the main pollutants were SO₂ and the pollutant structures were different. The largest influence was from the agricultural products' processing industry and papermaking industry.

Modified ecological footprint model based on emergy analysis and its application

WANG Guo-Gang, YANG De-Gang, ZHANG Xin-Huan, TANG Hong

2012, (3): 352-358. DOI: 10.7523/j.issn.2095-6134.2012.3.011

Abstract ( 1425 ) PDF (KB) ( 5 )

We modify the ecological footprint (EF) methodology based on the theory of emergy analysis, and two modified models of ecological footprint accounting are formulated and applied to a case study in Xinjiang. The comparison between the conventional and modified EF models based on the different views of ecological production is outlined. The results of comparison show that the modified models are reasonable and feasible, although the modified and traditional EF models are quite different in some principles.

Co-seismic tilt estimation based on baseline offset in accelerogram

WANG Long-Fei, ZHANG Wen-Bo

2012, (3): 359-366. DOI: 10.7523/j.issn.2095-6134.2012.3.012

Abstract ( 1105 ) PDF (KB) ( 3 )

We illustrate the impact of ground tilt on baseline offset in an accelerogram and propose a method of estimation of co-seismic tilt based on acceleration record in the near-field of an earthquake. The method is applied to the records from 33 carefully selected stations in the 2008 Wenchuan earthquake, and the validity of the method is preliminarily confirmed. Our results show that large tilts in magnitude are obtained in near-fault or rupture-toward stations. No obvious characteristic is found in distribution of the tilt direction. The validity of the method needs further confirmation.

SAR image recognition based on genetic programming

JIA Ya-Fei, ZHAO Feng-Jun, WANG Yan-Xia

2012, (3): 367-371. DOI: 10.7523/j.issn.2095-6134.2012.3.013

Abstract ( 1122 ) PDF (KB) ( 2 )

A genetic programming-based method for SAR image recognition is proposed. Five basic SAR image features are first extracted from SAR images, and then several new features are synthesized using the five basic features. Finally a support vector machine is used to complete classification. Experimental results show the effectiveness of this method.

Optimization and design of Delta antenna based on simulated annealing

ZHANG Feng, WANG Dong-Feng, JI Yi-Cai, FANG Guang-You, JU Han-Ji

2012, (3): 372-376. DOI: 10.7523/j.issn.2095-6134.2012.3.014

Abstract ( 1028 ) PDF (KB) ( 3 )

Delta antenna is a typical antenna for ionospheric vertical detection, and its radiation performance is mainly determined by the length and obliquity of the basic elements. To obtain better radiation characteristics an optimization method for designing Delta antenna is proposed, and the method is based on simulated annealing (SA) and the basic frequency method. The measured results using an optimized antenna at 1-30 MHz show that the optimization is fast and effective.

Interferometric calibration method of multi-strip airborne InSAR data using sparse GCPs

ZHANG Lin-Tao, HONG Jun, MING Feng, WANG Ke, HU Ji-Wei

2012, (3): 377-383. DOI: 10.7523/j.issn.2095-6134.2012.3.015

Abstract ( 1026 ) PDF (KB) ( 4 )

Calibration of multi-strip airborne InSAR data is needed in order to generate DEMs over large areas.We propose an interferometric calibration method for multi-strip InSAR data.The method can reduce the GCP number using connected points in the overlap area between strips and is shown to be effective by the experimental simulation. The results indicate that the interferometric parameter error of each strip can be calibrated accurately with a reduced number of GCP which could reduce the difficulty of InSAR outer calibration.

Joint source encryption coding based on CCSDS image data compression standard

LI Lin-Sen, ZHANG Can, CHEN De-Yuan

2012, (3): 384-391. DOI: 10.7523/j.issn.2095-6134.2012.3.016

Abstract ( 1016 ) PDF (KB) ( 2 )

The CCSDS IDC standard and SMS4 algorithm are separately designed for achieving the best performance of the overall system. However, they can not guarantee the transmission of the image data in the resources-limited network. We propose a joint source encryption algorithm based on CCSDS IDC standard. Randomized arithmetic coding is performed for the DC coefficients by using SMS4 sub-keys, and stream cipher for the AC coefficients. The simulation results show that this method has lower computational complexity and better security performance.

Automatic high-resolution latent palmprint segmentation

ZHOU Yu-Yang, A Yong, WU Min, WEN Cheng-Ming

2012, (3): 392-398. DOI: 10.7523/j.issn.2095-6134.2012.3.017

Abstract ( 1082 ) PDF (KB) ( 2 )

High-resolution latent palmprint image is one of the primary forensic evidences. However the image is still manually segmented for its huge size and complex texture. Two automatic segmentation algorithms are proposed to solve this problem. The first detects the background based on the frequencies of ULBP in each block. The other compares the texture dissimilarity between neighbor regions in each couple until all the regions grow up into the foreground and background. The experiments on the standard latent palmprint database show effectiveness of the two algorithms.

A new object recognition model based on feature integration theory

WANG Xi-Shun, LIU Xi, SHI Zhong-Zhi, SUI Hong-Jian

2012, (3): 399-405. DOI: 10.7523/j.issn.2095-6134.2012.3.018

Abstract ( 1156 ) PDF (KB) ( 2 )

We propose a new computational model for object recognition based on the vision cognitive findings. Feature integration theory offers the roadmap for our computing model. We construct the learning procedure to acquire necessary pre-knowledge for the recognition network on the basis of the hypothesis-maximum entropy principle. With the recognition network, we can bind the low-level image features and the high-level knowledge. Fundamental concepts and principles of conditional random fields are employed to model the binding process. We apply our model to real object recognition problem and evaluate it on the benchmark image databases to show its satisfactory performance.

A QoS-ensured dynamic XmtHoldoffExponent handshaking scheme in WiMAX Mesh network

HUANG Yan-Bin, YANG Shou-Bao, TENG Da, HE Wei-Qing, WANG Shu-Ling

2012, (3): 406-413. DOI: 10.7523/j.issn.2095-6134.2012.3.019

Abstract ( 1190 ) PDF (KB) ( 3 )

The three-way handshaking time affects delay of data packets and number of bandwidth requests in WiMAX Mesh network. A fixed handshaking parameter scheme can not satisfy different QoS demands. To solve these problems, we propose a QoSDx scheme to dynamically adjust handshake parameters according to the node itself, the numbers and priorities of two-hop neighbor nodes, and their parameters. Simulation results show that QoSDx improves the overall performance under different scale networks. The average of the throughputs of four kinds of services increases by 10%.

An integrated LTE/WLAN two-hop-relay architecture for throughput and energy efficiency enhancement

DONG Rong-Rong, HONG Pei-Lin, XUE Kai-Ping

2012, (3): 414-422. DOI: 10.7523/j.issn.2095-6134.2012.3.020

Abstract ( 1169 ) PDF (KB) ( 3 )

Although LTE network provides higher data rate, throughput of cell-edge users is lower than that of cell-center users because of inter-cell interference and higher path loss. For the same transmission power, lower throughput leads to lower energy efficiency. For the tri-sector site of LTE networks, we propose an integrated LTE/WLAN two-hop-relay architecture to enhance throughput of cell-edge users and energy efficiency of LTE networks. Theoretical analyses and simulation results show better performance of the new architecture.

Steganalysis of palette images based on run-length statistics and Walsh spectrum energy distribution

LI Hong-Yan, ZHAO Xian-Feng, HUANG Wei, SHENG Ren-Nong

2012, (3): 423-428. DOI: 10.7523/j.issn.2095-6134.2012.3.021

Abstract ( 956 ) PDF (KB) ( 2 )

A new method is proposed for palette image steganalysis based on the run-length statistics and the Walsh spectrum energy distribution. The P-value binary image is constructed and then 46-dimensional features are extracted from the run-length histogram and Walsh spectrum coefficients. Calibration is utilized to eliminate varieties caused by hosts. Experiments show that our scheme can successfully detect EzStego, sum of RGB-based steganography, and OPA with low embedding rates and it is superior to some prior arts.

On the linear complexity of output sequences of single-cycle T-function

LIU Jun, FAN Xiu-Bin, WU Chuan-Kun

2012, (3): 429-432. DOI: 10.7523/j.issn.2095-6134.2012.3.022

Abstract ( 1480 ) PDF (KB) ( 2 )

The single-cycle T-functions can be used as substitute for LFSR (linear feedback shift register) in stream ciphers, and such stream ciphers are very efficient in software. We have studied some cryptographic properties of single-cycle T-functions. We present the linear complexity and the minimal polynomial of the output sequences of single-cycle T-functions when n is an arbitrary positive integer.

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