Journal of University of Chinese Academy of Sciences

Fields of definition of a family of curves

ZHOU Yun

2007, 24 (6): 725-728. DOI: 10.7523/j.issn.2095-6134.2007.6.001

Let K be a finitely generated field extension of an algebraically closed
field k and C : f(x) = ayn be a curve over K, where char(k) - n, f(x) 2 k[x].
When n > 4, a 62 Kn and f has at least three simple zeros, the curve C is not defined over k.

Existence of positive periodic solutions to the differential equations with state-dependent delay

ZHANG Xiao-Ying; LIU Gui-Rong

2007, 24 (6): 729-736. DOI: 10.7523/j.issn.2095-6134.2007.6.002

Abstract ( 1780 ) PDF (KB) ( 6 )

In this paper ,we are concerned with the existence of positive periodic solutions to
the differential equations with state-dependent delay
x′(t) = −A(t, x(t))x(t) + B(x(t))F(x(t − (t, x(t)))).
Using Krasnoselskii fixed point theorem, we establish some sufficient condition for the existence
and nonexistence of positive !-periodic solutions to the above equation .

Lagrangian Gauss map of surfaces in R4

WU Zi-Ling

2007, 24 (6): 737-741. DOI: 10.7523/j.issn.2095-6134.2007.6.003

Abstract ( 2220 ) PDF (KB) ( 0 )

Given a closed oriented surface M immersed in R4, this note
will be concerned with the geometry of gº, the generalized Gauss map from
M into the Grassmann manifold G4,2 .

A recommendation algorithm based on support vector regression

WANG Hong-Yu, MI Zhong-Chun, LIANG Xiao-Yan, YE Yue-Xiang

2007, 24 (6): 742-748. DOI: 10.7523/j.issn.2095-6134.2007.6.004

Abstract ( 2683 ) PDF (KB) ( 0 )

Recommender systems and recommendation algorithm has become one of the hotspots of data mining research, with the rapid boosting of e-commerce. Support Vector Regression (SVR) algorithm has been introduced to construct a content-based recommend approach. First, the contents of rated items are analyzed with SVR to build regression model of user profiles for active users. Then use the user profiles to give recommendations. Experimental results on the EachMovie dataset shows that the proposed approach has better recommend performance and less time spending than the conventional collaborative filtering approach.

Study of a Large-scale Non-linear optimal model on　reverse logistics network

XU Han, ZHANG Min-Hong

2007, 24 (6): 749-755. DOI: 10.7523/j.issn.2095-6134.2007.6.005

Abstract ( 1914 ) PDF (KB) ( 0 )

The research of reverse logistics is receiving much attention recently along with growing environmental and the saving concern. This paper studies an non-linear mixed integer model of big size, multi-recover product reverse supply chain. Its objective is to minimize the total cost of the reverse net. Furthermore, a improved genetic algorithm is designed for the model. Finally, the model is tested on an example for illustrating its feasibility and effectiveness.

A modeling-based assessment study on nutrients transport　in Taihu Basin during 1960s

LAI Ge-Ying, YU Ge

2007, 24 (6): 756-764. DOI: 10.7523/j.issn.2095-6134.2007.6.006

Abstract ( 2050 ) PDF (0KB) ( 0 )

After industrial pollution in point source, land use/cover and other data in 1960s for SWAT model were estimated by statistical and modeling methods, spatial-temporal distribution of nutrient transport in Taihu Basin during 1960s was simulated and the effort factors of nutrient transport were analyzed using SWAT (Soil and Water Assessment Tool)model. The simulation results show that total nitrogen (TN) from external sources of nutrients into Taihu Lake in one year is less than 10000t, total phosphorus less than 1000t. The maximum of TP spatial distribution is located Zhexi Region and the maximum of TN spatial distribution is located Huxi Region. The results of sensitivity tests show that sewerage, which is one of five sensitivity factors (sewerage, industrial sources, livestock drainage, soil nutrients and losses of fertilizers in drained agricultural lands), has the max contribution to nutrients into Taihu Lake, 35.6% for TN, 38.4% for TP. are more than nutrients from other sources. The NPS is main form of external sources of nutrients into Lake Taihu, which contributes 76.6％ and 74.8％ of TN and TP respectively. Human activity has an important effort to nutrient transport into Taihu Lake.

Effects of acanthopanax senticosus extracts on digestion and absoption of amino acids in weaned piglets

YIN Fu-Gui, KONG Xiang-Feng, YIN Yu-Long, HE Qing-Hua, LIU He-Jun, HUANG Rui-Ling, TAN Bi-E, CHEN Li-Xiang, GAO Bi

2007, 24 (6): 765-770. DOI: 10.7523/j.issn.2095-6134.2007.6.007

Abstract ( 2048 ) PDF (KB) ( 0 )

This experiment was conducted to study the effects of acanthopanax senticosus (AS) extracts as dietary additive on digestion and absorption of protein or amino acids in weaned piglets. Sixty three-way crossbred piglets weaned at 21 days of age were randomly assigned to 3 treatment groups, representing supplementation with 0 or 1 g/kg of AS extracts, or 0.2 g/kg of colistin to maize- and soybean meal-based diets (n = 20 per group). Blood samples of 5 piglets per group were randomly collected on days 7, 14 and 28 after initiation of the addition to determine serum contents of free amino acids, then digesta at terminal ileum was collected to analyze the contents of amino acids after the sampled piglets were sacrificed. The results showed that the serum contents of amino acids in the extracts-supplemented group were gradually increased and digesta amino acid contents were gradually reduced at the same time as the experiment proceed when compared with the other 2 groups. These findings indicated that the AS extracts could enhance the ability of digestion and absorption of protein or amino acids, then improve the growth performance in weaned piglets.

An Improved K-means Algorithm Based on Optimizing Initial Points

QIN Yu, JING Ji-Wu, XIANG Ji, ZHANG Ai-Hua

2007, 24 (6): 771-777. DOI: 10.7523/j.issn.2095-6134.2007.6.008

Abstract ( 2784 ) PDF (KB) ( 19 )

K-means is an important clustering algorithm. It is widely used in Internet information processing technologies. Because the procedure terminates at a local optimum, K-means is sensitive to initial starting condition. An improved algorithm is proposed, which searches for the relative density parts of the database and then generates initial points based on them. The method can achieve higher clustering accuracies by well excluding the effects of edge points and outliers, as well as adapt to databases which have very skewed density distributions.

Non-malleable mercurial commitment scheme

XU Hai-Xia,LI Hong-Da, LI Bao

2007, 24 (6): 778-787. DOI: 10.7523/j.issn.2095-6134.2007.6.009

Abstract ( 1756 ) PDF (KB) ( 0 )

Mercurial commitment scheme is an interesting variation of regular com-
mitment scheme, which additionally allows for a soft decommit stage. The
soft decommitments are not required to binding but can not con°ict with the
true decommmitments (if the true decommmitments exist). In our paper, we
consider reusable non-malleable mercurial commitment schemes. Reusable
non-malleability is that the adversary accesses to an arbitrary number of
commitments, which is a strictly stronger security notion than general non-
malleability in which the adversary has access to only one commitment. We
adopt the reusability mainly due to the inherent property of mercurial com-
mitment scheme. We introduce the notion of reusable non-malleable mercu-
rial commitment scheme and give a construction based on the multi-trapdoor
mercurial commitment scheme.

A CMOS high performance 50MSPS sample/hold circuit

LI Tie, GUO Li, BAI Xue-fei

2007, 24 (6): 788-793. DOI: 10.7523/j.issn.2095-6134.2007.6.010

Abstract ( 2732 ) PDF (KB) ( 0 )

A high performance CMOS sample/hold circuit is presented, which achieves the precision of 10-bit over Nyquist band in 50-MHz sampling frequency at 3.3-V supply. This circuit uses full differential circuits, bottom-plate sampling, bootstrap circuits and high performance gain-boost operational amplifier. Simulation in 0.35-μm CMOS process shows the circuit consumes 18-mW of power.

Artificial immunology based anti-pollution P2P file sharing system

WEI Dong, YANG Shou-bao, JI Wen, LU Wei-na

2007, 24 (6): 794-800. DOI: 10.7523/j.issn.2095-6134.2007.6.011

Abstract ( 1714 ) PDF (KB) ( 0 )

The problem of file pollution is prevalent in p2p file sharing system nowadays. The pollution reduces the availability of system sharply. As the same as natural immune system, p2p file sharing system is also highly distributive, self-adaptive and self-organized. Vector space similarity is computed to weight the votes collected from other peers. Self-adaptive reputation threshold scheme is adopted to estimate the file authenticity. Artificial immunology based anti-pollution object reputation mechanism is established to select neighbor peer set and improve the system availability. Simulation results show that the system can distinguish between good and polluted files accurately and thwart the proliferation of pollution in the network with low communication cost.

Research and implementation on JavaScript-based invocating Web Services in Browser-Side

HE Li, WU Jian, JIA Yan-Min

2007, 24 (6): 801-805. DOI: 10.7523/j.issn.2095-6134.2007.6.012

Abstract ( 2486 ) PDF (KB) ( 0 )

For the requirement of communication between Browser and Server in WebOffice, A browser-side invocating Web Services method is proposed .Comparing with traditional server-side method, the advantages and weaknesses of this method are analyzed. Finally, JavaScript implementation is given: WSDL Loading and analyzing, SOAP packaging and binding, object serialization and deserialization

Study and comparisons of three ensemble pulsar time algorithm

ZHONG Chong–Xia ,YANG Ting–Gao

2007, 24 (6): 806-813. DOI: 10.7523/j.issn.2095-6134.2007.6.013

Abstract ( 2053 ) PDF (KB) ( 0 )

Pulsar time defined by single pulsar is influenced by several noise resources, to weaken these influence for gaining a more stable time scale, one can take ensemble analysis method to obtain ensemble pulsar time. Three algorithms of ensemble pulsar time are presented: classical weighted average algorithm, to gain the best long-term stability of ensemble pulsar time, one can choose the weight according to the long-term stability of each pulsars; the residuals of single pulsar can be decomposed by wavelet analysis in wavelet domain, and the component of different frequency range can be obtained. Then we can apply wavelet analysis algorithm to integrate the pulsar time, the weights are chosen according to reciprocal of wavelet average square error; The pulsar timing residuals are caused by reference atomic clock and pulsar itself, Wiener filtration analysis algorithm allows the separation of the contributions of an atomic clock and a pulsar itself to the post-fit pulsar timing residuals. The method allows to filter the atomic scale component from the pulsar phase variations. These three algorithms have been applied to the timing data of the millisecond pulsars PSR B1855+09 and PSR B1937+21. The result has indicated that the ensemble pulsar time obtained after the ensemble algorithm to pulsar time defined by several pulsar time weakens the influence of noise on a great extent, consequently improves the stability, furthermore the stability of the ensemble pulsar time obtained by wavelet analysis algorithm and Wiener filtration are better than the stability of the ensemble pulsar time obtained by sample weighted average algorithm. Obviously wavelet analysis algorithm and Wiener filtration are more feasible approach to deal with time-frequency signals.

Water information extraction of reservoir Shitoukoumen based on partial least squares regression

XU Jing-Ping, ZHANG Bai, SONG Kai-Shan, WANG Zong-Ming, LIU Dian-Wei, DUAN Hong-Tao

2007, 24 (6): 814-849. DOI: 10.7523/j.issn.2095-6134.2007.6.014

Abstract ( 2434 ) PDF (KB) ( 15 )

In the water color remote sensing, hyperspectral data always provide lots of information. However, retrieval of water constituents based on conventional statistical methods fails not only to make full use of the information, but also to remove the heavy correlation between spectral band-variables. Partial least squares regression (PLS) can solve the problem properly. In order to validate its feasibility in inland Case-Ⅱwaters, a PLS model was established to estimate Chlorophyll-a (Chl-a) concentrations and total suspended sediments(TSS) contents using hyperspectral data obtained from April to October in 2006 in the Reservoir Shitoukoumen. The results showed that: PLS model could make a relatively full use of hyperspectral data. Coefficients of different band-variables in the final model reflected absorption and scattering properties of Chl-a and TSS. Compared with bands ratio model and first-derivative reflectance model, PLS model overmatched the former two with high determination coefficients and satisfactory estimating results. It indicates that PLS is suitable for the inversion of water constituents in inland water Case-Ⅱ.

A community-based authentication method for Peer-to-Peer networks

JIA Su-Ping;　ZHANG Yu-Qing

2007, 24 (6): 820-828. DOI: 10.7523/j.issn.2095-6134.2007.6.015

Abstract ( 2375 ) PDF (KB) ( 0 )

In this paper, a novel authentication protocol called APExSPKI for P2P networks is proposed with the combination of certificate and trust. Trust being bound to certificate allows peers to perform authorization and access control as well as authentication. In addition, APExSPKI avoids the presence of central trusted authorities and allows every peer in the community to participate in the trust recommendation and be an agent to issue certificates for other peers, which fully embodies the equity and self-government of peers.

A non-coherent Imaging approach for ultra-wideband through-wall Radar

CHEN Jie;　FANG Guang-you;　LI Fang

2007, 24 (6): 829-834. DOI: 10.7523/j.issn.2095-6134.2007.6.016

Abstract ( 2539 ) PDF (KB) ( 0 )

Ultra-wideband (UWB) through-wall imaging radar is a promising technique and can be widely used for detecting and locating moving people through obstacles. Through-wall imaging radar employs coherent and non-coherent imaging techniques. In this paper we focus on a one-transmitter two-receiver non-coherent radar system. Analytical formulations of the target localization are given under the condition of both the absence of the wall and the presence of the wall. This paper also provides the cross-range resolution analysis and the supporting FDTD simulation results.

The processing of measurement data of langmuir probe based on wavelet transform

FU Zhu, CHENG Jian, CHEN Zhu, LIU Han-Fei

2007, 24 (6): 835-840. DOI: 10.7523/j.issn.2095-6134.2007.6.017

Abstract ( 1873 ) PDF (KB) ( 0 )

How to remove the noise cleanly and effectively without losing the property of the raw data in Langmuir Probe (LP) automatic measurement system when measuring the plasma parameters is an important question. And the normal method of data processing such as low-pass filter, moving average data processing can’t solve the question well. In this paper we use two types of wavelet transform to process the LP data step-by-step which are Daubechies Wavelet Transform (DWT) and Biorthogonal Wavelet Transform (BWT), and get quite good results. And in order to prove this, we comparative analyze the results of the actual data processed by several methods above.

Quantum coherent control of dynamic properties of double-dark-resonance atomic systems

NIU Yue-Ping, GONG Shang-Qing

2007, 24 (6): 841-846. DOI: 10.7523/j.issn.2095-6134.2007.6.018

Abstract ( 2223 ) PDF (KB) ( 0 )

In this thesis, quantum coherent control of dynamic properties of double-dark-resonance atomic systems is pursued in detail. First we show our scheme for creating atomic coherent superposition states via the technique of stimulated Raman adiabatic passage in a Lambda-type four-level system. With the application of a control field, it is found that the presence of double dark states leads to two arbitrary coherent superposition states with equal amplitude but inverse relative phases, even though the condition of multiphoton resonance is not met. Suitable manipulation of the control field and detunings makes the proposed scheme possible to create any coherent superposition states one desired. Then, in the above mentioned double-dark-resonant system, a scheme for giant enhancement of the Kerr nonlinearity is put forward. Compared with that generated in a single-dark-resonance system, the Kerr nonlinearity can be enhanced by several orders of magnitude with vanishing linear absorption. We attribute this dramatic enhancement to the interaction of dark resonances. As another possible means for enhancement of Kerr nonlinearity, spontaneously generated coherence is proposed. Meanwhile, a theoretical investigation is carried out in a five-level tripod system for obtaining a high efficiency double-channel four-wave-mixing process. By manipulating the intensity of the two coupling fields, the conversion efficiency of four-wave-mixing can be controlled

New approaches to test compression for digital circuits

HAN Yin-He, LI Xiao-Wei

2007, 24 (6): 847-857. DOI: 10.7523/j.issn.2095-6134.2007.6.019

Abstract ( 1724 ) PDF (KB) ( 0 )

Test compression has drawn significant attentions of academies and industries recently, since it can reduce test data volume and test application time of integrated circuits without losing fault coverage, therefore to diminish the gap between the test and manufacture camps. Based on test stimulus and test response, the test compression techniques can be classified to two categories, that is, test stimulus compression and test response compaction. This thesis conducts the research on both fields and presents several compression methods. The contributions of the thesis include: 1. This thesis presents a Variable-Tail code, and shows how to use this code to compress the test stimulus. Variable-Tail code is a variable-length-to-variable-length code. It can achieve higher test compression ratio in the case of high X-bit density. The experimental results show that the compression ratio of Variable-Tail with the proposed reordering algorithm is close to the theoretical upper bound of predictive codes (the average distance is only about 1.26%), meanwhile up to 20% of test power is saved. 2. This thesis presents the parallel core wrapper design. Studying on the distributions of X-bit, we find the phenomenon of full overlapping and partial overlapping of scan slices. When the slices overlap continuously, they can be loaded only once, thus test application time and test power are significantly saved. The experimental results show when the parallel core wrapper design is applied, compared with the serial core wrapper design, the test application time is reduced to 2/3 and test power is reduced to 1/15. 3．The 3X compression architecture is the main contribution of this thesis. The 3X architecture consists of three parts: X-Config stimulus compression, X-Balance test generation and X-Tolerant response compaction. X-Config stimulus decompression uses a periodically alterable MUXs network. X-Balance test generation considers the dynamic compaction, compression, scan chain design and periodically alterable MUXs network as a whole. It applies two algorithms, the one is the backward patterns remove algorithm and the other one is the specified bits based scan chain design algorithm. X-Tolerant response compaction uses a single-output compactor based on convolutional code. Since only one output pin is needed, X-Tolerant response compaction guarantees the highest compaction ratio. In order to achieve the X-Tolerant capacity, a multiple-weights basic check matrix generation algorithm is presented.

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