OALib Journal期刊

ISSN: 2333-9721




2019 ( 30 )

2018 ( 237 )

2017 ( 191 )

2016 ( 223 )


匹配条件: “CHEN” ,找到相关结果约74599条。
Digital Image Watermarking Based on Mixed Error Correcting Code  [PDF]
Yonghong Chen, Jiancong Chen
Journal of Information Security (JIS) , 2012, DOI: 10.4236/jis.2012.32018
Abstract: In this paper, we present a novel technique based on a mixed Error Correcting Code(ECC)-the convolutional code and the repetition code to enhance the robustness of the embedded watermark. Before embedding, the binary watermark is scanned to one-dimension sequence and later inputted into the (3, 1, 2) convolutional encoder and (3, 1) repetition encoder frame by frame, which will improve the error correcting capability of decoder. The output code sequence is scanned to some matrixes as the new watermark messages. The watermarking is selected in low frequency band of the Discrete Wavelet Transform (DWT) and therefore it can resist the destruction of image processing. Experimental results are presented to demonstrate that the robustness of a watermark with mixed ECC is much higher than the traditional one just with repetition coding while suffering JPEG lossy compression, salt and pepper noise and center cutting processing.
Operator Equation and Application of Variation Iterative Method  [PDF]
Ning Chen, Jiqian Chen
Applied Mathematics (AM) , 2012, DOI: 10.4236/am.2012.38127
Abstract: In this paper, we study some semi-closed 1-set-contractive operators A and investigate the boundary conditions under which the topological degrees of 1-set contractive fields, deg (I-A, Ω, p) are equal to 1. Correspondingly, we can obtain some new fixed point theorems for 1-set-contractive operators which extend and improve many famous theorems such as the Leray-Schauder theorem, and operator equation, etc. Lemma 2.1 generalizes the famous theorem. The calculation of topological degrees and index are important things, which combine the existence of solution of for integration and differential equation and or approximation by iteration technique. So, we apply the effective modification of He’s variation iteration method to solve some nonlinear and linear equations are proceed to examine some a class of integral-differential equations, to illustrate the effectiveness and convenience of this method.
Blow-Up and Attractor of Solution for Problems of Nonlinear Schrodinger Equations  [PDF]
Ning Chen, Jiqian Chen
Applied Mathematics (AM) , 2012, DOI: 10.4236/am.2012.312263
Abstract: In this paper, the authors study the blow-up of solution for a class of nonlinear Schrodinger equation for some initial boundary problem. On the other hand, the authors give out some analyses and that new conclusion by Eigen-function method. In last section, the authors check the nonlinear parameter for light rule power by using of parameter method to get ground state and excite state correspond case, and discuss the global attractor of some fraction order case, and combine numerical test. To illustrate this physics meaning in dimension d = 1, 2 case. So, by numerable solution to give out these wave expression.
Some Approximation in Cone Metric Space and Variational Iterative Method  [PDF]
Ning Chen, Jiqian Chen
Applied Mathematics (AM) , 2012, DOI: 10.4236/am.2012.312276
Abstract: In this paper, we give some new results of common fixed point theorems and coincidence point case for some iterative method. By using of variation iteration method and an effective modification of He’s variation iteration method discusses some integral and differential equations, we give out some new conclusion and more new examples.
Photoconductive Effect of Liquid and Utilization of Solar Energy  [PDF]
Ziwei Chen, Shihao Chen
Open Journal of Physical Chemistry (OJPC) , 2014, DOI: 10.4236/ojpc.2014.41003

Experiments described in this paper show that there is the photoconductive effect of liquid, i.e. when light shines into a sort of alkali, acid or salt solution, the conductivity of the solution will increase. The mechanism of the effect is explained as follows. When hydrated ions in the solution absorb photons with their high enough energies, they will decompose to naked ions and water-molecules. The naked ions can reach an anode or a cathode more easily and faster than the hydrated ions; It is possible that when a molecule in the solution absorbs a photon with its high enough energy, it will decompose to negative and positive ions. Based on the effect, a device producing hydrogen by the solar-energy had been devised.

Career Success of Knowledge workers: The Effects of Perceived Organizational Support and Person-Job Fit  [PDF]
Yu Chen
iBusiness (IB) , 2010, DOI: 10.4236/ib.2010.24051
Abstract: The purpose of this paper is to review relevant literatures on career success and develop a theoretical framework and testable propositions concerning how person-job ?t and perceived organizational support relate to career success.
The earth dynamic system: the earth rotation vs mantle convection  [PDF]
Shuping Chen
Natural Science (NS) , 2010, DOI: 10.4236/ns.2010.212162
Abstract: The earth dynamic system is one of the key scientific questions on the earth science. The thermodynamic behavior and gravity force of the earth and the rheology nature of the mantle prove that mantle convection is the main power source leading the lithosphere to break and move. Yet the directivity of both the structures in the crust and plate movement reminds of the earth rotation. Here we demonstrate that the mantle convection and inertia force of the earth rotation affect each other, the former being the power source of lithosphere plate break and motion, and the latter determining the direction of the mantle convection and plate motion. The sense of plate motion depends on the mantle upwells, whose trends are controlled by the earth rotation. The geometric shapes of the plate boundaries can adjust the direction of plate movement.
Skyhook Surface Sliding Mode Control on Semi-Active Vehicle Suspension System for Ride Comfort Enhancement  [PDF]
Yi Chen
Engineering (ENG) , 2009, DOI: 10.4236/eng.2009.11004
Abstract: A skyhook surface sliding mode control method was proposed and applied to the control on the semi-active vehicle suspension system for its ride comfort enhancement. A two degree of freedom dynamic model of a vehicle semi-active suspension system was given, which focused on the passenger’s ride comfort perform-ance. A simulation with the given initial conditions has been devised in MATLAB/SIMULINK. The simula-tion results were showing that there was an enhanced level of ride comfort for the vehicle semi-active sus-pension system with the skyhook surface sliding mode controller.
Combining Keyword Search Advertisement and Site- Targeted Advertisement in Search Engine Advertising  [PDF]
Li Chen
Journal of Service Science and Management (JSSM) , 2008, DOI: 10.4236/jssm.2008.13025
Abstract: Internet advertising has seen a strong growth in recent years and search engine advertising has played an important role in that growth. Search engines continue to expand their business by providing new options of advertising. For ex-ample, Google provides a new advertisement mechanism based on cost-per-thousand-impression (CPM) payment called “site-targeted advertisement” in addition to the famous “keyword search advertisement” based on cost-per-click (CPC). While keyword search advertisement is a cost-efficient way of advertising, site-targeted advertisement provides a quicker alternative to expose the ad to a mass population at a higher expense. This paper studies a mixed strategy of optimization by combining these mechanisms to exploit their corresponding advantages. We set up a general model to find optimal starting and ending times for both methods. Closed-form solutions are calculated for two applications: (1) Advertising of perishable information with click-based revenue only; and (2) Site-targeted advertisement first and key-word search advertisement last. Comparative static analysis provides an analysis of properties of each application. We also develop a computational experiment based on Google AdWords to illustrate the application of the model.
Orthogonal-Least-Squares Forward Selection for Parsimonious Modelling from Data  [PDF]
Sheng CHEN
Engineering (ENG) , 2009, DOI: 10.4236/eng.2009.12008
Abstract: The objective of modelling from data is not that the model simply fits the training data well. Rather, the goodness of a model is characterized by its generalization capability, interpretability and ease for knowledge extraction. All these desired properties depend crucially on the ability to construct appropriate parsimonious models by the modelling process, and a basic principle in practical nonlinear data modelling is the parsimonious principle of ensuring the smallest possible model that explains the training data. There exists a vast amount of works in the area of sparse modelling, and a widely adopted approach is based on the linear-in-the-parameters data modelling that include the radial basis function network, the neurofuzzy network and all the sparse kernel modelling techniques. A well tested strategy for parsimonious modelling from data is the orthogonal least squares (OLS) algorithm for forward selection modelling, which is capable of constructing sparse models that generalise well. This contribution continues this theme and provides a unified framework for sparse modelling from data that includes regression and classification, which belong to supervised learning, and probability density function estimation, which is an unsupervised learning problem. The OLS forward selection method based on the leave-one-out test criteria is presented within this unified data-modelling framework. Examples from regression, classification and density estimation applications are used to illustrate the effectiveness of this generic parsimonious modelling approach from data.

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