Showing papers by "University of Electronic Science and Technology of China published in 2007"

Bipartite network projection and personal recommendation.

Abstract: One-mode projecting is extensively used to compress bipartite networks. Since one-mode projection is always less informative than the bipartite representation, a proper weighting method is required to better retain the original information. In this article, inspired by the network-based resource-allocation dynamics, we raise a weighting method which can be directly applied in extracting the hidden information of networks, with remarkably better performance than the widely used global ranking method as well as collaborative filtering. This work not only provides a creditable method for compressing bipartite networks, but also highlights a possible way for the better solution of a long-standing challenge in modern information science: How to do a personal recommendation.

Nanomedicine for drug delivery and imaging : A promising avenue for cancer therapy and diagnosis using targeted functional nanoparticles

Abstract: The diagnosis and treatment of cancer or tumor at the cellular level will be greatly improved with the development of techniques that enable the delivery of analyte probes and therapeutic agents into cells and cellular compartments. Organic and inorganic nanoparticles that interface with biological systems have recently attracted widespread interest in the fields of biology and medicine. The new term nanomedicine has been used recently. Nanoparticles are considered to have the potential as novel intravascular or cellular probes for both diagnostic (imaging) and therapeutic purposes (drug/gene delivery), which is expected to generate innovations and play a critical role in medicine. Target-specific drug/gene delivery and early diagnosis in cancer treatment is one of the priority research areas in which nanomedicine will play a vital role. Some recent breakthroughs in this field recently also proved this trend. Nanoparticles for drug delivery and imaging have gradually been developed as new modalities for cancer therapy and diagnosis. In this article, we review the significance and recent advances of gene/drug delivery to cancer cells, and the molecular imaging and diagnosis of cancer by targeted functional nanoparticles.

Dual-Band Bandpass Filters Using Stub-Loaded Resonators

Abstract: Dual-band bandpass filters using novel stub-loaded resonators (SLRs) are presented in this letter. Characterized by both theoretical analysis and full-wave simulation, the proposed SLR is found to have the advantage that the even-mode resonant frequencies can be flexibly controlled whereas the odd-mode resonant frequencies are fixed. Based on the proposed SLR, a dual-band filter is implemented with three transmission zeros. To further improve the selectivity, a filter with four transmission zeros on either side of both passbands is designed by introducing spur-line. The measured results validate the proposed design.

Fabrication and gas sensitivity of polyaniline–titanium dioxide nanocomposite thin film

Abstract: A polyaniline–titanium dioxide (PANI/TiO2) nanocomposite was prepared by an in-situ chemical oxidation polymerization approach in the presence of colloidal TiO2 at room temperature, and the PANI/TiO2 nanocomposite thin film was formed on a silicon substrate covered with interdigital electrodes to fabricate a gas sensor via the self-assembly method. The gas-responses of the PANI/TiO2 thin film to NH3 and CO toxic gases were examined. The results showed that the response, reproducibility and stability of the PANI/TiO2 thin film to NH3 were superior to CO gas. Compared with NH3 and CO gases, humidity had less effect on the resistance of the PANI/TiO2 thin film. It was also found that the difference between pure PANI and PANI/TiO2 thin films was not only in gas-sensing property but also in surface morphology.

An efficient method for reliability evaluation of multistate networks given all minimal path vectors

Abstract: The multistate networks under consideration consist of a source node, a sink node, and some independent failure-prone components in between the nodes. The components can work at different levels of capacity. For such a network, we are interested in evaluating the probability that the flow from the source node to the sink node is equal to or greater than a demanded flow of d units. A general method for reliability evaluation of such multistate networks is using minimal path (cut) vectors. A minimal path vector to system state d is called a d-MP. Approaches for generating all d-MPs have been reported. Given that all d-MPs have been found, the issue becomes how to evaluate the probability of the union of the events that the component state vector is greater than or equal to at least one of the d-MPs. There is a need for a more efficient method of determining the probability of this union of events. In this paper, we report an efficient recursive algorithm for this union probability evaluation based on the Su...

Optimal reliability, warranty and price for new products

Abstract: The success of a new product depends on both engineering decisions (product reliability) and marketing decisions (price, warranty). A higher reliability results in a higher manufacturing cost and higher sale price. Consumers are willing to pay a higher price only if they can be assured about product reliability. Product warranty is one such tool to signal reliability with a longer warranty period indicating better reliability. Better warranty terms result in increased sales and also higher expected warranty servicing costs. Warranty costs are reduced by improvements in product reliability. Learning effects result in the unit manufacturing cost decreasing with total sales volume and this in turn impacts on the sale price. As such, reliability, price and warranty decisions need to be considered jointly. The paper develops a model to determine the optimal product reliability, price and warranty strategy that achieve the biggest total integrated profit for a general repairable product sold under a free replac...

Effect of initial configuration on network-based recommendation

Abstract: In this paper, based on a weighted object network, we propose a recommendation algorithm, which is sensitive to the configuration of initial resource distribution. Even under the simplest case with binary resource, the current algorithm has remarkably higher accuracy than the widely applied global ranking method and collaborative filtering. Furthermore, we introduce a free parameter $\beta$ to regulate the initial configuration of resource. The numerical results indicate that decreasing the initial resource located on popular objects can further improve the algorithmic accuracy. More significantly, we argue that a better algorithm should simultaneously have higher accuracy and be more personal. According to a newly proposed measure about the degree of personalization, we demonstrate that a degree-dependent initial configuration can outperform the uniform case for both accuracy and personalization strength.

An experimental and computational study on intramolecular charge transfer: a tetrathiafulvalene-fused dipyridophenazine molecule.

Abstract: To study the electronic interactions in donor-acceptor (D-A) ensembles, D and A fragments are coupled in a single molecule. Specifically, a tetrathiafulvalene (TTF)-fused dipyrido[3,2-a:2',3'-c]phenazine (dppz) compound having inherent redox centers has been synthesized and structurally characterized. Its electronic absorption, fluorescence emission, photoinduced intramolecular charge transfer, and electrochemical behavior have been investigated. The observed electronic properties are explained on the basis of density functional theory.

Edge-based scoring and searching method for identifying condition-responsive protein–protein interaction sub-network

Abstract: Motivation: Current high-throughput protein–protein interaction (PPI) data do not provide information about the condition(s) under which the interactions occur. Thus, the identification of condition-responsive PPI sub-networks is of great importance for investigating how a living cell adapts to changing environments. Results: In this article, we propose a novel edge-based scoring and searching approach to extract a PPI sub-network responsive to conditions related to some investigated gene expression profiles. Using this approach, what we constructed is a sub-network connected by the selected edges (interactions), instead of only a set of vertices (proteins) as in previous works. Furthermore, we suggest a systematic approach to evaluate the biological relevance of the identified responsive sub-network by its ability of capturing condition-relevant functional modules. We apply the proposed method to analyze a human prostate cancer dataset and a yeast cell cycle dataset. The results demonstrate that the edge-based method is able to efficiently capture relevant protein interaction behaviors under the investigated conditions. Contact: guoz@ems.hrbmu.edu.cn Supplementary information: Supplementary data are available at Bioinformatics online.

Combining Spatial Filters for the Classification of Single-Trial EEG in a Finger Movement Task

Abstract: Brain-computer interface (BCI) is to provide a communication channel that translates human intention reflected by a brain signal such as electroencephalogram (EEG) into a control signal for an output device. In recent years, the event-related desynchronization (ERD) and movement-related potentials (MRPs) are utilized as important features in motor related BCI system, and the common spatial patterns (CSP) algorithm has shown to be very useful for ERD-based classification. However, as MRPs are slow nonoscillatory EEG potential shifts, CSP is not an appropriate approach for MRPs-based classification. Here, another spatial filtering algorithm, discriminative spatial patterns (DSP), is newly introduced for better extraction of the difference in the amplitudes of MRPs, and it is integrated with CSP to extract the features from the EEG signals recorded during voluntary left versus right finger movement tasks. A support vector machines (SVM) based framework is designed as the classifier for the features. The results show that, for MRPs and ERD features, the combined spatial filters can realize the single-trial EEG classification better than anyone of DSP and CSP alone does. Thus, we propose an EEG-based BCI system with the two feature sets, one based on CSP (ERD) and the other based on DSP (MRPs), classified by SVM

Room-temperature ferromagnetism in pure and Co doped CeO(2) powders

Abstract: We report the room-temperature (RT) ferromagnetism (FM) observed in pure and Co doped CeO2 powder. An insulating nonmagnetic CeO2 single crystal, after grinding into fine powder, shows an RT-FM with a small magnetization of 0.0045 emu g−1. However, the CeO2 powder became paramagnetic after oxygen annealing, which strongly suggests an oxygen vacancy meditated FM ordering. Furthermore, by doping Co into CeO2 powder the FM can significantly enhance through a F-centre exchange (FCE) coupling mechanism, in which both oxygen vacancies and magnetic ions are involved. As the Co content increases, the FM of Co doped CeO2 initially increases to a maximum 0.47 emu g−1, and then degrades very quickly. The complex correlation between the Co content and saturation magnetization was well interpreted by supposing the coexistence of three subsets of Co ions in CeO2. Our results reveal that the large RT-FM observed in Co doped CeO2 powder originates from a combination effect of oxygen vacancies and transition metal doping.

In-line fiber-optic etalon formed by hollow-core photonic crystal fiber

Abstract: A novel fiber-optic in-line etalon formed by splicing a section of hollow-core photonic crystal fiber (HCPCF) in between two single-mode fibers is proposed and demonstrated, for the first time to our knowledge. Such a HCPCF-based etalon acts as an excellent optical waveguide to form a Fabry-Perot interferometer and hence allows the cavity length to be as long as several centimeters with good visibility as the transmission loss of the HCPCF is much smaller than that of a hollow core fiber; this offers great potential to generate a practical dense fiber-optic sensor network with spatial frequency division-multiplexing. This novel etalon is demonstrated for strain measurement, and the experimental results show that a good visibility of 0.3 and a strain accuracy of better than ±5μe are achieved.

Spatiotemporal Sensing in Cognitive Radio Networks

Abstract: Cognitive radio networks need to continuously monitor spectrum to detect the presence of the licensed users. In this paper, we have exploited spatial diversity in multiuser networks to improve the spectrum sensing capabilities of centralized cognitive radio (CR) networks. We develop a fixed and a variable relay sensing scheme. The fixed relay scheme employs a relay that is fixed in location to help the cognitive network base station detect the presence of the primary user. The variable relay sensing scheme employs cognitive users distributed at various locations as relays to sense data and to improve the detection capabilities. We theoretically prove that the proposed variable relay sensing scheme effectively reduces the average detection time which is also illustrated by an insightful example. Finally, we introduce a useful metric to measure the performance of fixed relay and variable relay schemes.

PVDF coated quartz crystal microbalance sensor for DMMP vapor detection

Abstract: A quartz crystal microbalance (QCM) modified with poly(vinylidene fluoride) (PVDF) was fabricated and used for detection of dimethyl methylphosphonate (DMMP) vapor, a simulant of nerve agents using a drop-coating method. Measurements were based on the frequency shifts due to the adsorption of DMMP vapor on the surface of the modified electrodes. It was found that frequency shifts were linear to the concentrations of analyte in the range of 5–60 ppm with a correlation coefficient of above 0.997. The influences of temperature and humidity on the sensors were also examined. Results showed that the sensitivity to DMMP vapor was almost identical in various humidity circumstances, and the sensitivity was higher in a lower temperature range.

A new structure and its analytical model for the electric field and breakdown voltage of SOI high voltage device with variable-k dielectric buried layer

Abstract: A new SOI high voltage device structure with variable- k (permittivity) dielectric buried layer (VK SOI) is proposed in this paper. In this structure, the buried layer is made of two dielectrics, one of which is the low- k dielectric. The breakdown voltage is enhanced due to the modulation effect of the variable- k buried layer on the electric fields in the buried layer and drift region. An analytical model for the electric field and breakdown voltage in VK SOI is presented taking the modulation effect into account, from which the RESURF condition is derived. The dependences of the electric field distribution and breakdown voltage on the device parameters for VK SOI are investigated. Compared with the conventional SOI, the electric field of the buried layer and breakdown voltage of VK SOI with relative permittivity k I2 = 2 of the low- k dielectric are enhanced by 81% and 56%, respectively. The analytical results are in good agreement with those of 2D simulations. Finally, the proposed model and RESURF condition can be well applied to the conventional SOI and also extended to VT SOI (variable thickness buried layer SOI) devices.

Stochastic synchronization of genetic oscillator networks.

Abstract: Background The study of synchronization among genetic oscillators is essential for the understanding of the rhythmic phenomena of living organisms at both molecular and cellular levels Genetic networks are intrinsically noisy due to natural random intra- and inter-cellular fluctuations Therefore, it is important to study the effects of noise perturbation on the synchronous dynamics of genetic oscillators From the synthetic biology viewpoint, it is also important to implement biological systems that minimizing the negative influence of the perturbations

EADEEG:An Energy-Aware Data Gathering Protocol for Wireless Sensor Networks

Abstract: In this paper, a hierarchical clustering protocol for long-lived sensor network is proposed. EADEEG (an energy-aware data gathering protocol for wireless sensor networks) achieves a good performance in terms of lifetime by minimizing energy consumption for communications and balancing the energy load among all nodes. EADEEG adopts a new clustering parameter for cluster head election, which can better handle the hetergenous energy capacities. Furthermore, it also adopts a simple but efficient approach, namely intra-cluster coverage to cope with the fractional area coverage problem. Through turning off redundant nodes, while the remaining nodes stay active to provide continuous service, the network lifetime can be significantly prolonged. Experimental results have shown that EADEEG can satisfy the desired coverage fraction and outperform LEACH (low energy adaptive clustering hierarchy), PEGASIS (power-efficient gathering in sensor information systems) and DEEG (distributed energy-efficient data gathering and aggregation protocol) in terms of network lifetime.

Hybrid LPFG/MEFPI sensor for simultaneous measurement of high-temperature and strain.

Abstract: A hybrid fiber-optic sensor consisting of a long-period fiber grating (LPFG) and a micro extrinsic Fabry-Perot (F-P) interferometric (MEFPI) sensor is proposed and demonstrated for simultaneous measurement of high-temperature and strain. The LPFG written by using high-frequency CO2 laser pulses is used for high-temperature measurement while the MEFPI sensor fabricated by using 157nm F2 laser pulses is used for strain measurement under high temperature. The distinguishing feature of such a hybrid fiber-optic sensor is that it can stand for high temperature of up to 650°C and achieve precise measurement of strain under high temperature conditions simultaneously.

Effects of ion irradiation and annealing on optical and structural properties of CeO2 films on sapphire

Abstract: (001) CeO2 films deposited on r-cut sapphire were irradiated by N+ ions at fluences of 1 x 10(16), 5 x 10(16) and 1 x 10(17) ion/cm(2) at room temperature and then annealed at 200-900 degrees C in O-2 ambient X-ray diffraction results showed that there was no change for the orientation and crystallinity of CeO2 film after irradiation However, the diffraction peaks became sharper after annealing at 900 degrees C Atomic force microscope measurements revealed isolated voids after ion irradiation The optical transmittance spectra indicated a blueshift of band gap due to the valence transition of Ce3+-> Ce4+ induced by thermal annealing As-deposited films exhibited three photoluminescence bands at 300-390, 380-550, and 460-550 nm A new emission band peaked at 670 nm appeared while the emission band at 460-550 nm disappeared after annealing The CeO2 films show good thermal stability and irradiat on resistance except some isolated voids in this work (c) 2006 Elsevier BV All rights reserved

The Research of Improved Apriori Algorithm for Mining Association Rules

Abstract: The efficiency of mining association rules is an important field of Knowledge Discovery in Databases. The Apriori algorithm is a classical algorithm in mining association rules. This paper presents an improved Apriori algorithm to increase the efficiency of generating association rules. This algorithm adopts a new method to reduce the redundant generation of sub-itemsets during pruning the candidate itemsets, which can form directly the set of frequent itemsets and eliminate candidates having a subset that is not frequent in the meantime. This algorithm can raise the probability of obtaining information in scanning database and reduce the potential scale of itemsets.

Gas sensing characteristics of WO3 vacuum deposited thin films

Abstract: Tungsten trioxide (WO3) thin films were prepared by vacuum thermal deposition and subsequently annealed in the temperature range of 300–600 °C. X-ray diffractometry (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM) were employed to analyze the structure and the morphology of the fabricated thin films. The results showed that the average grain size changed considerably with the variation of annealing temperature. Using a pair of interdigitated Au electrodes and glass ceramics as a substrate, the humidity and NO2 sensing properties of the WO3 thin films, manifested in relative conductivity changes, were measured. The results showed that the humidity sensitivity of the WO3 thin films was strongly dependent on the annealing temperature, and annealing and working temperature played an important role in the NO2 sensing characteristics.

Mutation pressure shapes codon usage in the GC-Rich genome of foot-and-mouth disease virus.

Abstract: Foot-and-mouth disease (FMD) is economically the most important viral-induced livestock disease worldwide. In this study, we report the results of a survey of codon usage bias of FMD virus (FMDV) representing all seven serotypes (A, O, C, Asia 1, SAT 1, SAT 2, and SAT 3). Correspondence analysis, a commonly used multivariate statistical approach, was carried out to analyze synonymous codon usage bias. The analysis showed that the overall extent of codon usage bias in FMDV is low. Furthermore, the good correlation between the frequency of G + C at the synonymous third position of sense codons (GC3S) content at silent sites of each sequence and codon usage bias suggested that mutation pressure rather than natural (translational) selection is the most important determinant of the codon bias observed. In addition, other factors, such as the lengths of open reading frame (ORF) and the hydrophobicity of genes also influence the codon usage variation among the genomes of FMDV in a minor way. The result of phylogenetic analyses based on the relative synonymous codon usage (RSCU) values indicated a few obvious phylogenetic incongruities, which suggest that more FMDV genome diversity may exist in nature than is currently indicated. Our work might give some clues to the features of FMDV genome and some evolutionary information of this virus.

A Novel Method for Preparing V-doped Titanium Dioxide Thin Film Photocatalysts with High Photocatalytic Activity Under Visible Light Irradiation

Abstract: The liquid phase deposition (LPD) method was successfully used for preparing V-doped TiO2 thin film photocatalysts. In this simple and easily-controlled process, V-doped anatase TiO2 thin films were directly deposited on a soda lime glass substrate placed in an aqueous solution containing Ti- and V-fluoro complex ions, followed by annealing. The thin films were analyzed by XRD, XPS, UV-vis. V4+ ions were introduced into the lattice of TiO2 through in-situ substituting Ti4+. The absorption edge of V-doped TiO2 films shifted to visible light region. The highly efficient photocatalytic activity was verified by the decomposition of methylene blue under visible light irradiation.

The dynamic complexity of a three-species Beddington-type food chain with impulsive control strategy

Abstract: In this paper, by using theories and methods of ecology and ordinary differential equation, the dynamics complexity of a prey–predator system with Beddington-type functional response and impulsive control strategy is established. Conditions for the system to be extinct are given by using the Floquet theory of impulsive equation and small amplitude perturbation skills. Furthermore, by using the method of numerical simulation with the international software Maple, the influence of the impulsive perturbations on the inherent oscillation is investigated, which shows rich dynamics, such as quasi-periodic oscillation, narrow periodic window, wide periodic window, chaotic bands, period doubling bifurcation, symmetry-breaking pitchfork bifurcation, period-halving bifurcation and crises, etc. The numerical results indicate that computer simulation is a useful method for studying the complex dynamic systems.