scispace - formally typeset
Search or ask a question

Showing papers by "National University of Defense Technology published in 2006"


Journal ArticleDOI
TL;DR: A common base is provided for the first time to analyze and compare Gaussian filters with respect to accuracy, efficiency and stability factor and to help design more efficient filters by employing better numerical integration methods.
Abstract: This paper proposes a numerical-integration perspective on the Gaussian filters. A Gaussian filter is approximation of the Bayesian inference with the Gaussian posterior probability density assumption being valid. There exists a variation of Gaussian filters in the literature that derived themselves from very different backgrounds. From the numerical-integration viewpoint, various versions of Gaussian filters are only distinctive from each other in their specific treatments of approximating the multiple statistical integrations. A common base is provided for the first time to analyze and compare Gaussian filters with respect to accuracy, efficiency and stability factor. This study is expected to facilitate the selection of appropriate Gaussian filters in practice and to help design more efficient filters by employing better numerical integration methods

284 citations


Journal ArticleDOI
TL;DR: This paper presents a new adaptive controller for image-based dynamic control of a robot manipulator using a fixed camera whose intrinsic and extrinsic parameters are not known, and proves asymptotic convergence of the image errors to zero by the Lyapunov theory.
Abstract: This paper presents a new adaptive controller for image-based dynamic control of a robot manipulator using a fixed camera whose intrinsic and extrinsic parameters are not known. To map the visual signals onto the joints of the robot manipulator, this paper proposes a depth-independent interaction matrix, which differs from the traditional interaction matrix in that it does not depend on the depths of the feature points. Using the depth-independent interaction matrix makes the unknown camera parameters appear linearly in the closed-loop dynamics so that a new algorithm is developed to estimate their values on-line. This adaptive algorithm combines the Slotine-Li method with on-line minimization of the errors between the real and estimated projections of the feature points on the image plane. Based on the nonlinear robot dynamics, we prove asymptotic convergence of the image errors to zero by the Lyapunov theory. Experiments have been conducted to verify the performance of the proposed controller. The results demonstrated good convergence of the image errors

263 citations


Journal ArticleDOI
TL;DR: In this article, the authors provided the band structure of flexural waves in an Euler-Bernoulli beam with locally resonant structures, with two degrees of freedom, i.e., a resonator with vertical and rotational vibration.
Abstract: Using the transfer matrix theory, we provided the band structure of flexural waves in an Euler-Bernoulli beam with locally resonant structures, with two degrees of freedom, i.e., a resonator with vertical and rotational vibration. The frequency response function of a finite periodic system was calculated by the finite element method. The material damping of rubber makes the gaps wider in the calculation. These theoretical results show a good agreement with those of the experiment. The measured result provides an attenuation of over $20\phantom{\rule{0.3em}{0ex}}\mathrm{dB}$ in the frequency range of the band gaps. The existence of low-frequency band gaps in such a beam provides a method of flexural vibration control of beams.

197 citations


Journal ArticleDOI
TL;DR: In this paper, the secret transmitting order of particles (STE) protocol was improved by using techniques used in the protocol presented by Zhu et al. [A.D. Zhu, Y. Xia, Q.B. Fan, S. Zhang, Zhang, Phys. Rev. Lett.

163 citations


Journal ArticleDOI
TL;DR: In this paper, the influence of heat treatment at 1400°C on PAN-based high strength carbon fiber was investigated by means of TG, XRD, XPS as well as the tensile test.

142 citations


Journal ArticleDOI
TL;DR: There are structural abnormalities of the hippocampus, the ACC and the insular cortex in patients with PTSD due to fire, and the following three regions of reduced gray matter volume were found in Patients with PTSD compared with controls.
Abstract: Voxel-based morphometry (VBM) is an objective whole-brain technique for characterizing regional cerebral volume and tissue concentration differences in structural magnetic resonance images. In the current study, we used VBM to examine possible cerebral gray matter abnormalities in patients with posttraumatic stress disorder (PTSD) due to fire. The subjects included 12 victims of a fire disaster with PTSD and 12 matched victims of the same fire without PTSD. Magnetic resonance images were obtained on a 1.5-Tesla General Electric scanner at Central South University, and an entire brain volume of 248 contiguous slices was obtained for each subject. Then, gray matter density in patients with PTSD and control groups was compared by using a VBM approach in SPM2. Group analysis was thresholded at P<0.001, uncorrected, at the voxel level. The following three regions of reduced gray matter volume were found in patients with PTSD compared with controls: left hippocampus, left anterior cingulate cortex (ACC), and bilateral insular cortex. It was concluded that there are structural abnormalities of the hippocampus, the ACC and the insular cortex in patients with PTSD due to fire.

141 citations


Journal ArticleDOI
TL;DR: In this paper, a scheme for probabilistic remote preparation of the four-particle Greenberger-Horne-Zeilinger (GHZ) class state by using two partial entangled threeparticle GHZ states as the quantum channel is presented.

138 citations


Journal ArticleDOI
TL;DR: This work presents a light-by-light photonic crystal configuration consisting of a bend waveguide with three embedded Kerr-type nonlinear rods and a T-branch waveguide that can demonstrate all-optical AND gate operation with extremely high-contrast between the OFF state and ON state in its transmission.
Abstract: We present a light-by-light photonic crystal configuration consisting of a bent waveguide with three embedded Kerr-type nonlinear rods and a T-branch waveguide. We show that such a configuration can also demonstrate all-optical AND gate operation with extremely high contrast between the OFF state and the ON state in its transmission. The photonic crystal configuration of all-optical light-by-light switching is simple and thus facilitates the fabrication of practical all-optical devices and further large-scale optical integration.

126 citations


Journal ArticleDOI
TL;DR: The experiment results show that the new feature extraction method with grouped weight for protein sequence is efficient to extract the structure information implicated in protein sequence and the method has reached a satisfied performance despite its simplicity.

125 citations


Journal ArticleDOI
TL;DR: In this article, the fabrication and characterisation of high-quality silicon membrane photonic crystals are reported, and the etching process is carefully optimized to give holes with very smooth and vertical sidewalls, resulting in propagation, with a minimum loss of 4.1 plusmn 0.9 dB/cm in a single line defect (W1) waveguide.
Abstract: The fabrication and characterisation of high-quality silicon membrane photonic crystals are reported. The etching process was carefully optimised to give holes with very smooth and vertical sidewalls, resulting in propagation, with a minimum loss of 4.1plusmn0.9 dB/cm in a single line defect (W1) waveguide

115 citations


Journal ArticleDOI
TL;DR: In this paper, the authors generalize Yeo and Chua's results to teleporting an arbitrary $N$-qubit state via a genuine four qubit entanglement channel.
Abstract: Recently Yeo and Chua [Phys. Rev. Lett. 96, 060502 (2006)] presented an explicit protocol for faithfully teleporting an arbitrary two-qubit state via a genuine four-qubit entanglement channel. Here we generalize completely their results to teleporting an arbitrary $N$-qubit state via genuine $N$-qubit entanglement channels. And we present the general form of the genuine multipartite entanglement channels, namely, the sufficient and necessary condition the genuine $N$-qubit entanglement channels must satisfy to teleport an arbitrary $N$-qubit state.

Journal ArticleDOI
TL;DR: In this paper, the propagation of longitudinal elastic waves in quasi-one-dimensional structure consisting of harmonic oscillators periodically jointed on a slender beam is studied, and the stiffness and mass ratios are found analytically as two factors that influence the actual attenuation in the band gap of the locally resonant phononic crystals.
Abstract: The propagation of longitudinal elastic waves in quasi one-dimensional structure consisting of harmonic oscillators periodically jointed on a slender beam is studied. Sub-frequency locally resonant band gap with highly asymmetric attenuation is observed in both theoretical and experimental results, and both results match well. The stiffness and mass ratios are found analytically as two factors that influence the actual attenuation in the band gap of the locally resonant phononic crystals. The study on the weights of the two factors shows that the stiffness ratio is the key one. Thus, the reason for the mismatch between the regions of the sharp attenuation and the theoretical band gap in the locally resonant phononic crystals is discovered.

Journal ArticleDOI
TL;DR: A scheme for systematically estimating fingerprint ridge orientation and segmenting fingerprint image by means of evaluating the correctness of the ridge orientation based on neural network is proposed and is compared with VeriFinger 4.2 published by Neurotechnologija Ltd. in 2004, and the comparison shows that the proposed scheme leads to an improved accuracy of minutiae detection.

Journal Article
TL;DR: The progress of the multipath routing technique is surveyed, various routing protocols are described and evaluated, which cover most types of multipath routed protocols, and a comparison and discussion of their respective merits and drawbacks are provided.
Abstract: There are significant differences between wire networks and MANETs.MANETs have nodes with high mobility,limited bandwidth resources,and variable topology.Therefore,there is a need for new routing protocols,which solves all these drawbacks.Most routing protocols for MANETs do not take fairness into account.They tend to have a heavy burden on the hosts along the shortest path from a source to a destination.As a result,heavily loaded hosts may deplete power energy quickly,which will lead to network disconnections and failure of application sessions.There have been some methods of multipath routing to solve the question.In this paper,the progress of the multipath routing technique is surveyed,and various routing protocols are described and evaluated,which cover most types of multipath routing protocols,and then provide a comparison and discussion of their respective merits and drawbacks.Finally,the future research directions are outlined.

Journal ArticleDOI
TL;DR: A more robust learning algorithm for an MNN-based on unscented Kalman filter (UKF) is derived and is closer to optimal fashion in nonlinear filtering compared with traditional methods.
Abstract: The extended Kalman filter (EKF) is well known as a state estimation method for a nonlinear system and has been used to train a multilayered neural network (MNN) by augmenting the state with unknown connecting weights. However, EKF has the inherent drawbacks such as instability due to linearization and costly calculation of Jacobian matrices, and its performance degrades greatly, especially when the nonlinearity is severe. In this letter, first a more robust learning algorithm for an MNN-based on unscented Kalman filter (UKF) is derived. Since it gives a more accurate estimate of the linkweights, the convergence performance is improved. The algorithm is then extended further to develop a NN-aided UKF for nonlinear state estimation. The NN in this algorithm is used to approximate the uncertainty of the system model due to mismodeling, extreme nonlinearities, etc. The UKF is used for both NN online training and state estimation simultaneously. Simulation results show that the new algorithm is very effective and is closer to optimal fashion in nonlinear filtering compared with traditional methods

Journal ArticleDOI
TL;DR: In this paper, a non-local damping model including time and spatial hysteresis effects is used for the dynamic analysis of structures consisting of Euler-Bernoulli beams and Kirchoff plates.

Journal ArticleDOI
TL;DR: A nearest neighbor method has been introduced to discriminate GPCRs from non-GPCRs and subsequently classify GPCR at four levels on the basis of amino acid composition and dipeptide composition of proteins.
Abstract: G-protein coupled receptors (GPCRs) are transmembrane proteins which via G-proteins initiate some of the important signaling pathways in a cell and are involved in various physiological processes. Thus, computational prediction and classification of GPCRs can supply significant information for the development of novel drugs in pharmaceutical industry. In this paper, a nearest neighbor method has been introduced to discriminate GPCRs from non-GPCRs and subsequently classify GPCRs at four levels on the basis of amino acid composition and dipeptide composition of proteins. Its performance is evaluated on a non-redundant dataset consisted of 1406 GPCRs for six families and 1406 globular proteins using the jackknife test. The present method based on amino acid composition achieved an overall accuracy of 96.4% and Matthew's correlation coefficient (MCC) of 0.930 for correctly picking out the GPCRs from globular proteins. The overall accuracy and MCC were further enhanced to 99.8% and 0.996 by dipeptide composition-based method. On the other hand, the present method has successfully classified 1406 GPCRs into six families with an overall accuracy of 89.6 and 98.8% using amino acid composition and dipeptide composition, respectively. For the subfamily prediction of 1181 GPCRs of rhodopsin-like family, the present method achieved an overall accuracy of 76.7 and 94.5% based on the amino acid composition and dipeptide composition, respectively. Finally, GPCRs belonging to the amine subfamily and olfactory subfamily of rhodopsin-like family were further analyzed at the type level. The overall accuracy of dipeptide composition-based method for the classification of amine type and olfactory type of GPCRs reached 94.5 and 86.9%, respectively, while the overall accuracy of amino acid composition-based method was very low for both subfamilies. In comparison with existing methods in the literature, the present method also displayed great competitiveness. These results demonstrate the effectiveness of our method on identifying and classifying GPCRs correctly. GPCRsIdentifier, a corresponding stand-alone executable program for GPCR identification and classification was also developed, which can be acquired freely on request from the authors for academic purposes.

Journal ArticleDOI
TL;DR: All three-photon entangled states are used to transmit the secret message except those chosen for eavesdropping check and the present scheme has a high source capacity because Greenberger–Horne–Zeilinger state forms a large Hilbert space.

Journal ArticleDOI
TL;DR: The basic concepts and models of weapon-target assignment (WTA) are introduced and the mathematical nature of the WTA models is also analyzed and directions for the future research on dynamic WTA are discussed.

Journal ArticleDOI
TL;DR: In this article, the authors proposed a PZT-driven synthetic-jet actuator (SJA) for zero net mass flux (NMS) devices, which can be coupled with MEMS sensors, control and logic electronics into a single very lightweight and compact device.
Abstract: I N the last 20 years, much attention has been given to developing microfluidic systems [1]. Among them, synthetic-jet actuators (SJA) have been intensely studied recently [2]. Synthetic-jet actuators have many potential applications such as jet vectoring [3,4], boundary-layer control [5,6], combustion control [7], and micro-pumps [8], etc. A synthetic-jet actuator is a zero net mass flux device. Figure 1a shows a typical structure of an existing SJA, which is composed of an exit slot (or orifice) and a diaphragm (or double diaphragms [9]) mounted to enclose a volume of fluid in a cavity. Piezoelectric (PZT) diaphragms are used in most minior microSJAs because of their size, rapid time response, and relatively low power consumption. The PZT-driven SJA also fits within the microelectromechanical system (MEMS) discipline and can be coupled with MEMS sensors, control and logic electronics into a single very lightweight and compact device. Unfortunately, the pressure loading limits to obtain a small deflection of the PZTdiaphragm on the existing SJA requires a high power to drive the PZT-diaphragm when the pressure differential between the base flow (to be controlled by the SJA) and the environment is large. This limits applications of the SJA. In addition, the diaphragm of the existing SJA (as shown in Fig. 1a) has one surface exposed to the fluid drawn from the base flow and the other surface exposed to the environment, which indicates that half of the radiation energy of the vibrating diaphragm is wasted in the environment. Keeping the advantages of a PZT-driven SJA,while resolving themajor problems of pressure loading and energy inefficiency, is the main impetus for designing a new generation SJA. A newSJA prototype is schematically shown in Fig. 1b. It consists of two cavities, a PZT-diaphragm, two exit slots, and a slide block (SB). In the new SJA concept, two adjacent jets are established under the two exit slots and are driven by the motion of the same PZTdiaphragm. The slide block regulates the two jets (as shown in Figs. 1b–1d), and then two adjacent jets merge into a single, larger synthetic jet. In this Note, numerical simulations are conducted to study the new SJA. We include a discussion focused on the novelty and merits of the new SJA in comparison with the existing SJAs.

Journal Article
TL;DR: A node contraction method of evaluation of node importance in complex networks is proposed based on a new evaluation criterion, i.e. the most important node is the one whose contraction results in the largest increase of the networks agglomeration.

Journal ArticleDOI
TL;DR: In this article, the effect of shaft material on the vibration attenuation in band gap is investigated and the frequency response function of the shaft with finite periodic locally resonant oscillators is simulated with finite element method.

Journal ArticleDOI
TL;DR: In this article, two simple spring-mass models are constructed in order to evaluate the frequencies on both the lower and upper edges of the lowest locally resonant band gaps of the ternary locally- resonant phononic crystals.
Abstract: Based on a better understanding of the lattice vibration modes, two simple spring–mass models are constructed in order to evaluate the frequencies on both the lower and upper edges of the lowest locally resonant band gaps of the ternary locally resonant phononic crystals. The parameters of the models are given in a reasonable way based on the physical insight into the band gap mechanism. Both the lumped-mass methods and our models are used in the study of the influences of structural and the material parameters on frequencies on both edges of the lowest gaps in the ternary locally resonant phononic crystals. The analytical evaluations with our models and the theoretical predictions with the lumped-mass method are in good agreement with each other. The newly proposed heuristic models are helpful for a better understanding of the locally resonant band gap mechanism, as well as more accurate evaluation of the band edge frequencies.

Book ChapterDOI
11 Jun 2006
TL;DR: This paper proposes an SVM based approach to hierarchical relation extraction, using features derived automatically from a number of GATE-based open-source language processing tools, and uses several new features including part of speech tag, entity subtype, entity class, entity role, semantic representation of sentence and WordNet synonym set.
Abstract: Automatic extraction of semantic relationships between entity instances in an ontology is useful for attaching richer semantic metadata to documents. In this paper we propose an SVM based approach to hierarchical relation extraction, using features derived automatically from a number of GATE-based open-source language processing tools. In comparison to the previous works, we use several new features including part of speech tag, entity subtype, entity class, entity role, semantic representation of sentence and WordNet synonym set. The impact of the features on the performance is investigated, as is the impact of the relation classification hierarchy. The results show there is a trade-off among these factors for relation extraction and the features containing more information such as semantic ones can improve the performance of the ontological relation extraction task.

Journal ArticleDOI
TL;DR: The proposed kernel locality preserving projections (KLPP) algorithm consists of two steps: kernel principal component analysis (KPCA) plus LPP, and provides an outline for implementing KLPP.

Journal ArticleDOI
TL;DR: An indirect replication algorithm is proposed following the intrinsic characteristic of distributed storage systems and the peer-to-peer model and has less granularity of replication, less bandwidth and storage costs, and provides higher availability, durability, and security.
Abstract: Replication is a key technology of distributed storage systems. In this paper, an indirect replication algorithm is proposed following the intrinsic characteristic of distributed storage systems and the peer-to-peer model. In the indirect replication algorithm, the data object is partitioned into several data blocks. These data blocks are encoded in order that there is data redundancy between data blocks. Comparing with the traditional replication algorithm, the indirect replication algorithm has less granularity of replication, less bandwidth and storage costs, and provides higher availability, durability, and security. The performance evaluation shows that the encoding and decoding times are proportional to the data size, and that the irregular cascade bipartite graphs are of great advantage in improving the success ratio of data recovery. Finally, if the number of data blocks used to recover the data object is larger than a certain value, the success ratio of data recovery approaches 100%.

Proceedings ArticleDOI
23 Apr 2006
TL;DR: WSNs QoS requirements within a WSNs application, and then analyzing Issues for QoS Monitoring is defined, and problems in this paper are analyzed.
Abstract: Sensor networks are distributed networks made up of small sensing devices equipped with processors, memory, and short-range wireless communication. They differ from traditional computer networks in that they have resource constraints, unbalanced mixture traffic, data redundancy, network dynamics, and energy balance. Work within wireless sensor networks (WSNs) Quality of service (QoS) has been isolated and specific either on certain functional layers or application scenarios. However the area of sensor network quality of service (QoS) remains largely open. In this paper we define WSNs QoS requirements within a WSNs application, and then analyzing Issues for QoS Monitoring.

Journal ArticleDOI
TL;DR: In this article, the existence of travelling wave fronts of delayed reaction diffusion systems with partial quasi-monotonicity was studied and the Schauder's fixed point theorem was applied to some appropriate operator in this subset.
Abstract: This paper deals with the existence of travelling wave fronts of delayed reaction diffusion systems with partial quasi-monotonicity. We propose a concept of “desirable pair of upper-lower solutions”, through which a subset can be constructed. We then apply the Schauder’s fixed point theorem to some appropriate operator in this subset to obtain the existence of the travelling wave fronts.

Journal ArticleDOI
TL;DR: Based on phase cancellation, a new technology is proposed to achieve a motion target range profile via stepped-frequency waveform that does not need the estimation of the velocity of the target.
Abstract: In radar target imaging, motion induces a range-Doppler coupling effect, which results in distortion in synthesizing a range profile for a moving target. To eliminate or suppress the distortion of the synthetic range profile, conventional technology such as motion compensation requires velocity estimation. Unfortunately, for a high-speed moving target, it is difficult to achieve real-time accurate estimation of the velocity of the target. Based on phase cancellation, a new technology is proposed to achieve a motion target range profile via stepped-frequency waveform. The new technology does not need the estimation of the velocity. Hence, its computational cost can be minimized. It is also easier to use. The simulation result confirms the effect of the new technology

Journal ArticleDOI
TL;DR: In this paper, a novel planar photonic band gap (PBG) scheme is presented for size reduction, the proposed structure can be considered as a kind of distorted uniplanar compact-PBG (DUC-PFG) while being even more compact in size.
Abstract: A novel planar photonic band-gap (PBG) scheme is presented for size reduction, the proposed structure can be considered as a kind of distorted uniplanar compact-PBG (DUC-PBG) while being even more compact in size. Its design is detailed in this letter, and several experimental results are presented, the properties of the proposed DUC-PBG are examined, as compared with that of the conventional UC-PBG.