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Search Results: 1 - 10 of 125743 matches for " Y. Chen "
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An Alternative Approach to Particle-Particle Collisions  [PDF]
C. Y. Chen
Journal of Modern Physics (JMP) , 2015, DOI: 10.4236/jmp.2015.66082
Abstract: A new alternative approach to the statistical behavior of particle-particle collisions is introduced. The alternative approach is derived rigorously from well known mechanical laws; and the results given by it, quantitatively and qualitatively different from what the standard kinetic theory yields, can be directly checked with computer-simulated or realistic experiments. More importantly, from the introduction of it, a number of new concepts and new methodologies emerge, which might turn out to be very significant to the future development of nonequilibrium statistical mechanics.
The Lanczos-Chebyshev Pseudospectral Method for Solution of Differential Equations  [PDF]
Peter Y. P. Chen
Applied Mathematics (AM) , 2016, DOI: 10.4236/am.2016.79083
Abstract: In this paper, we propose to replace the Chebyshev series used in pseudospectral methods with the equivalent Chebyshev economized power series that can be evaluated more rapidly. We keep the rest of the implementation the same as the spectral method so that there is no new mathematical principle involved. We show by numerical examples that the new approach works well and there is indeed no significant loss of solution accuracy. The advantages of using power series also include simplicity in its formulation and implementation such that it could be used for complex systems. We investigate the important issue of collocation point selection. Our numerical results indicate that there is a clear accuracy advantage of using collocation points corresponding to roots of the Chebyshev polynomial.
A Scalable Method for Cross-Platform Merging of SNP Array Datasets  [PDF]
Peikai Chen, Y. S. Hung
Engineering (ENG) , 2013, DOI: 10.4236/eng.2013.510B103

Single nucleotide polymorphism (SNP) array is a recently developed biotechnology that is extensively used in the study of cancer genomes. The various available platforms make cross-study validations/comparisons difficult. Meanwhile, sample sizes of the studies are fast increasing, which poses a heavy computational burden to even the fastest PC.Here, we describe a novel method that can generate a platform-independent dataset given SNP arrays from multiple platforms. It extracts the common probesets from individual platforms, and performs cross-platform normalizations and summari-zations based on these probesets. Since different platforms may have different numbers of probes per probeset (PPP), the above steps produce preprocessed signals with different noise levels for the platforms. To handle this problem, we adopt a platform-dependent smoothing strategy, and produce a preprocessed dataset that demonstrates uniform noise levels for individual samples.To increase the scalability of the method to a large number of samples, we devised an algorithm that split the samples into multiple tasks, and probesets into multiple segments before submitting to a parallel computing facility. This scheme results in a drastically reduced computation time and increased ability to process ultra-large sample sizes and arrays.

Expressogram: A Visualization of Cytogenetic Landscape in Cancer Samples Using Gene Expression Microarrays  [PDF]
Peikai Chen, Y. S. Hung
Engineering (ENG) , 2013, DOI: 10.4236/eng.2013.510B102

In cancer genomes, there are frequent copy number aberration (CNA) events, some of which are believed to be tumori-genic. While copy numbers can be detected by a number of technologies, e.g., SNP arrays, their relations with gene expressions are not well clarified. Here, we describe an approach to visualize the global relations between copy numbers and gene expressions using expression microarrays. We mapped the gene expression signals detected by microar-ray probesets onto a reference human genome, the RefSeq, based on their annotated physical positions, resulting in a landscape that we called expressogram. To study the expressograms under various conditions and their relations with cytogenetic events, such as CNAs, we obtained three classes of array samples, namely samples of a cancer (e.g., liver cancer), normal samples in the same tissue, and normal samples of other tissues. We developed a Bayesian based algorithm to estimate a background signal from the latter two sources for the cancer samples. By subtracting the estimated background from the raw signals of the cancer samples, and subjecting the differences to a kernel-based smoothing scheme, we produced an expressogram that shows strong consistency with the copy numbers. This indicates that copy numbers are on average positively correlated with and have strong impacts on gene expressions. To further explore the applicability of these findings, we submit the expressograms to the significant CNA detection algorithm GISTIC. The results strongly indicate that expressogram can also be used to infer copy number events and significant regions of CNA affected dysregulation.

An ARX-Based PID-Sliding Mode Control on Velocity Tracking Control of a Stick-Slip Pi-ezoelectric-Driven Actuator  [PDF]
Y. Cao, X. B. Chen
Modern Mechanical Engineering (MME) , 2015, DOI: 10.4236/mme.2015.51002
Abstract: Piezoelectric-driven stick slip actuators have been drawn more and more attention in the nano- positioning application due to the high accuracy and theoretical unlimited displacement. However, the hysteresis of piezoelectric actuator (PEA) and the nonlinear friction force between the end- effector and the stage make control of piezoelectric-driven stick slip actuator challenge. This paper presents the development of an autoregressive exogenous (ARX)-based proportional-integral-derive (PID)-sliding mode control (SMC) for the velocity tracking control of the piezoelectric-driven stick slip actuator. Stability is guaranteed by rigorously choosing the appropriate PID parameters and the zero steady state error is achieved. To verify the effectiveness of the proposed method, experiments were carried out on a commercially-available piezoelectric-driven stick slip actuator. The tracking errors were compared with the traditional PID controller, illustrating that in spite of existing of modeling error, the ARX-based PID-SMC is able to better improve the velocity tracking performance of piezoelectric-driven stick slip actuator, compared with the traditional PID controller.
Bilingualized Dictionaries with Special Reference to the Chinese EFL Context
Y Chen
Lexikos , 2012,
Abstract: As a type of dictionary with huge popularity among EFL learners in China, the bilingualized dictionary (BLD) deserves more academic and pedagogical attention than it receives nowadays. This article gives an overview of the BLD within the framework of dictionary research, including dictionary history, dictionary typology, dictionary criticism and dictionary use. It first traces, with a special reference to the Chinese EFL context, the origin and historical development of this type of dictionary, and then proposes several approaches to its classification. The strengths and weaknesses of the BLD are evaluated and its role in language pedagogy discussed, followed by an extensive review of the empirical studies of BLD use. Finally, further areas of BLD research are also suggested. It is hoped that such an overview would kindle more research interest in BLDs which is relevant to language pedagogy, dictionary use instruction and lexicographic practices.
A Legacy System Encapsulation Strategy Based on Web Service  [PDF]
D. J. Chen, X. Y. Li
Creative Education (CE) , 2012, DOI: 10.4236/ce.2012.37B014

In order to migrate the enterprise legacy system to the web, a multi-agent based legacy system encapsulation model is proposed.  Firstly, the characteristics of legacy system are analyzed, and then the data and functions that need to be published are confirmed. Secondly the legacy system is wrapped into web components with common interface, and these components are managed by the application server. Thirdly, the clients can send requests to the application server, and receive the return result from the application server.  Due to adoption of wrapping technology for legacy system, original security and stability of legacy system are guaranteed in the web components. Finally, the validity and practicability of the migration technology are verified through the application in the encapsulation of Matlab as web components.

Producing Renewable Biodiesel Fuel Using the Transesterification Process  [PDF]
T. W. Chung, Y. J. Chen
World Journal of Engineering and Technology (WJET) , 2015, DOI: 10.4236/wjet.2015.33C016

Biodiesel fuels are considered an alternative to fossil fuels. This is one of the effective means of transferring solar energy to dynamic energy via photosynthesis. It is also being considered in order to reduce the levels of carbon dioxide production worldwide. Biodiesel fuels are a renewable, biodegradable, and clean energy source. Producing enough biofuels to replace fossil fuels will bring the advantages of reduced air pollution and reduced other environmental impacts of fossil fuels. In this study, the response surface methodology (RSM) was used to design the experimental runs and to discuss the manufacturing variables on the transesterification of palm oil into fatty acid methyl ester (i.e. biodiesel fuel). The variation of the degree of effect for each variable in the transesterification process was observed. A second-order model was obtained to predict the yield of biodiesel fuel and the viscosity as a function of the reaction time, the mass fraction of catalyst in methanol and the molar ratio of methanol to plant oil. The experimental data of the yield and the viscosity of biodiesel fuels in different manufacturing variables are discussed in this study. Analysis of variance (ANOVA) was also applied to discuss the main factor and interaction factor effects of the manufacturing variables on the responses of the yield of unrefined biodiesel fuels. The shortage of farmland in Taiwan is a problem that needs to be solved before mass propagation of biofuels can be accomplished. In southeastern Asia, there are many farms and most energy farm products are cultivated (e.g. palm oil or Jatropha oil). In addition to sunflowers and soybeans in Taiwan, those energy farm products are possible choices for production of biodiesel fuel in Taiwan. The cooperation between Indonesia and Taiwan on the plantation of palm or Jatropha trees in Indonesia has conducted and will be one of the possible ways to solve the problem of the shortage of energy farm products in Taiwan.

Ecophysiological responses of winter wheat seedling to aerosol wet deposition of Xi'an area, China
Ecophysiological responses of winter wheat seedling to aerosol wet deposition of Xi’an area, China

Chen Yiping,

环境科学学报(英文版) , 2010,
Abstract: The fluorescence staining method and scanning electron microscopy (SEM) were used to study the e ect of ozone (O3) inactivating Cryptosporidium in water and cell ultrastructures variation to shed light on the mechanism of inactivation preliminarily. Results indicated that O3 had a stronger inactivating capability. When the concentration of O3 was above 3.0 mg/L and the contact time was up to 7 min, a significant inactivating e ect could be achieved. The turbidity on inactivation e ects was also found to be statistically significant in artificial water.With increases in turbidity, the inactivating e ect decreased. Inactivation rate improved with a temperature increase from 5 to 25°C, but decreased beyond this. The inactivating capability of O3 was found to be stronger under acidic than that under alkalic conditions. When the concentration of organic matter in the reaction system was increased, the competition between Cryptosporidium and organics with O3 probably took place, thereby reducing the inactivation rate. In addition, the cellular morphology of Cryptosporidium varied with di erent contact times. At zero contact time, cells were rotundity and sphericity, at 60 sec they became folded, underwent emboly, and burst at 480 sec, the cell membrane of Cryptosporidium shrinked and collapsed completely.
The genetic type and tectonic setting of ore associated mesozoic porphyries in the Eastern Qinling Mountains
Y. J. Chen
Chinese Science Bulletin , 1998, DOI: 10.1007/BF02891396
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