This article investigated the particle size effect of micro-sized SiC on the tribological behavior of SiCp-reinforced AZ91D Mg-based metal–matrix composites (MMCs). The Mg MMCs were prepared by the melt-stirring technique for wear
tests. The hardness and coefficient of friction of Mg MMCs increases as particle size of SiC particle in MMCs increases, except
for the hardness tendency at the region between particle size of 11 and 15 μm. The SiCp/AZ91D MMCs exhibit superior wear resistance under lower and moderate sliding condition. However, the effects of the SiC particle
reinforcements on wear resistance are not as conclusive under severe sliding condition, since the matrix of MMCs were softened
at elevated temperature under such a severe condition. 相似文献
In this article, a Box-Cox transformation-based annealing robust radial basis function networks (ARRBFNs) is proposed for
an identification algorithm with outliers. Firstly, a fixed Box-Cox transformation-based ARRBFN model with support vector
regression (SVR) is derived to determine the initial structure. Secondly, the results of the SVR are used as the initial structure
in the fixed Box-Cox transformation-based ARRBFNs for the identification algorithm with outliers. At the same time, an annealing
robust learning algorithm (ARLA) is used as the learning algorithm for the fixed Box-Cox transformation-based ARRBFNs, and
applied to adjust the parameters and weights. Hence, the fixed Box-Cox transformation-based ARRBFNs with an ARLA have a fast
convergence speed for an identification algorithm with outliers. Finally, the proposed algorithm and its efficacy are demonstrated
with an illustrative example in comparison with Box-Cox transformation-based radial basis function networks. 相似文献
In this paper, we propose the weighted fusion, a new penalized regression and variable selection method for data with correlated variables. The weighted fusion can potentially incorporate information redundancy among correlated variables for estimation and variable selection. Weighted fusion is also useful when the number of predictors p is larger than the number of observations n. It allows the selection of more than n variables in a motivated way. Real data and simulation examples show that weighted fusion can improve variable selection and prediction accuracy. 相似文献
Many application domains are increasingly leveraging service-oriented architecture (SOA) techniques to facilitate rapid system
deployment. Many of these applications are time-critical and, hence, real-time assurance is an essential step in the service
composition process. However, there are gaps in existing service composition techniques for real-time systems. First, admission
control is an essential technique to assure the time bound for service execution, but most of the service composition techniques
for real-time systems do not take admission control into account. A service may be selected for a workflow during the composition
phase, but then during the grounding phase, the concrete service may not be able to admit the workload. Thus, the entire composition
process may have to be repeated. Second, communication time is an important factor in real-time SOA, but most of the existing
works do not consider how to obtain the communication latencies between services during the composition phase. It is clear
that maintaining a full table of communication latencies for all pairs of services is infeasible. Obtaining communication
latencies between candidate services during the composition phase can also be costly, since many candidate services may not
be used for grounding. Thus, some mechanism is needed for estimating the communication latency for composite services. In
this paper, we propose a three-phase composition approach to address the above issues. In this approach, we first use a highly
efficient but moderately accurate algorithm to eliminate most of the candidate compositions based on estimated communication
latencies and assured service response latency. Then, a more accurate timing prediction is performed on a small number of
selected compositions in the second phase based on confirmed admission and actual communication latency. In the third phase,
specific concrete services are selected for grounding, and admissions are actually performed. The approach is scalable and
can effectively achieve service composition for satisfying real-time requirements. Experimental studies show that the three-phase
approach does improve the effectiveness and time for service composition in SOA real-time systems. In order to support the
new composition approach, it is necessary to effectively specify the needed information. In this paper, we also present the
specification model for timing-related information and the extension of OWL-S to support this specification model. 相似文献
One major goal of functional genomics has been to identify and analyze molecular interactions in a cellular context to better understand the underlying design principles and mechanisms. To investigate into a PPI network from both topological and functional points of view, this work proposes a methodology that exploits ontology-based biological knowledge for network analysis. To speed up the procedure, an agent-based framework is also presented for supporting distributed computing. The preliminary results show that through the knowledge obtained from gene ontology, our work in analyzing building blocks of PPI networks can give a higher resolution than that of previous ones. Also our agent-based framework can successfully speed up the task of network analysis in an adaptive manner. 相似文献
Watermarking protocols are designed for tracing illegal distributors when unauthorized copies are found. So far, most of the proposed schemes set up two or more watermarks embedded to a copy by the seller before it was sold. The main potential concerns of multiple watermarking are the image quality would be damaged and any earlier embedded watermarks would be destroyed as well. Thanks to visual cryptography which encodes the secret image into two shares, and recovers the secret by collecting these two shares. Therefore, a new buyer-seller watermarking protocol is proposed in this paper by applying the technique of visual cryptography to Lei et al.’s scheme so as to free from the disadvantages of multiple-watermarking insertion.
The electronic structures of quasi-one-dimensional ferrimagnetic Ca3Co2O6 are investigated using the generalized gradient approximation (GGA) as well as the GGA plus on-site Coulomb interaction (GGA+U) scheme. GGA+U calculations reveal that the interchain ferrimagnetic Ca3Co2O6 is a Mott–Hubbard insulator rather than a metal given from GGA. In addition, we found an on-site U induced 3z2−r2 orbital ordering on Copri sublattice which drives the intrachain ferromagnetic coupling along c-axis. Our findings suggest that strong electron-electron correlation plays an important role in Ca3Co2O6. 相似文献
Abstract— This study is intended to explore the legibility and visual fatigue of different age users under various surface treatments and reflectance of electronic paper. Through the method of character‐search task, the results indicated that compared with single types of treatment [anti‐reflection (AR) 0.8%, anti‐glare, 43% haze), the compound treatment of anti‐reflection and anti‐glare (ARC) exhibited the same legibility, and it showed superior properties to effectively reduce visual fatigue. Hence, it is suggested that electronic‐paper manufacturers should choose the compound surface treatment for better visual performance. On the other hand, the findings also validated that enhancing the reflectance of electronic paper to the same level as regular paper (about 80%) is worthy to be practically implemented. Based on the results of this study, electronic‐paper manufacturers can take useful information to fulfill ergonomic requirements on product design. 相似文献
This paper introduces a model-based hand gesture recognition system, which consists of three phases: feature extraction,
training, and recognition. In the feature extraction phase, a hybrid technique combines the spatial (edge) and the temporal
(motion) information of each frame to extract the feature images. Then, in the training phase, we use the principal component
analysis (PCA) to characterize spatial shape variations and the hidden Markov models (HMM) to describe the temporal shape
variations. A modified Hausdorff distance measurement is also applied to measure the similarity between the feature images
and the pre-stored PCA models. The similarity measures are referred to as the possible observations for each frame. Finally,
in recognition phase, with the pre-trained PCA models and HMM, we can generate the observation patterns from the input sequences,
and then apply the Viterbi algorithm to identify the gesture. In the experiments, we prove that our method can recognize 18
different continuous gestures effectively.
Received: 19 May 1999 / Accepted: 4 September 2000 相似文献