Comparison of 2D and 3D prediction models for environmental vibration induced by underground railway with two types of tracks

Two-dimensional (2D) and three-dimensional (3D) prediction models for environmental vibration induced by underground railway with direct fixation track and steel spring floating slab track are developed and verified. The responses of ground surface calculated by 2D prediction models with various equivalent forces are compared to those calculated by 3D prediction models. The numerical results show that (a) the computational time for each case calculated by 2D prediction models is more than 500 times less than that calculated by 3D prediction models, however, the accuracy of 2D prediction models is relatively lower than 3D prediction models, so 3D prediction models are required for absolute prediction due to their higher accuracy and applicability to a wider range of complex problems; and (b) a suitable equivalent force transfer method for 2D prediction models can improve the prediction accuracy of 2D prediction models, the equivalent forces in 2D prediction models are respectively recommended to use the equivalent wheel-rail force and the equivalent steel spring force averaged over a vehicle length for underground direct fixation track and steel spring floating slab trac

Sparse Multicasting Simulator For Optical Networks

All-optical networks are networks where fibers are connected using optical switches and data remain in the optical domain from its source to destination. Wavelength-division multiplexing (WDM) divides the bandwidth of an optical fiber into many non-overlapping wavelengths, each independently operated at peak electronic speeds. The data transmission route in an optical network from the source to the destination is called a lightpath. By equipping the intermediate routing nodes with multicasting capability, a light-tree can be constructed for a multicast connection session. During the course of this project, a multicasting simulator for optical networks was developed and some tests on NSFNET network topology were conducted using the simulator. Specifically, the simulator includes: (1) Dynamic or static multicast tree construction; (2) Sparse multicasting mode for both static and dynamic multicast tree construction, as well as sparse wavelength conversion mode for static multicast tree c..

Scene text detection via extremal region based double threshold convolutional network classification.

In this paper, we present a robust text detection approach in natural images which is based on region proposal mechanism. A powerful low-level detector named saliency enhanced-MSER extended from the widely-used MSER is proposed by incorporating saliency detection methods, which ensures a high recall rate. Given a natural image, character candidates are extracted from three channels in a perception-based illumination invariant color space by saliency-enhanced MSER algorithm. A discriminative convolutional neural network (CNN) is jointly trained with multi-level information including pixel-level and character-level information as character candidate classifier. Each image patch is classified as strong text, weak text and non-text by double threshold filtering instead of conventional one-step classification, leveraging confident scores obtained via CNN. To further prune non-text regions, we develop a recursive neighborhood search algorithm to track credible texts from weak text set. Finally, characters are grouped into text lines using heuristic features such as spatial location, size, color, and stroke width. We compare our approach with several state-of-the-art methods, and experiments show that our method achieves competitive performance on public datasets ICDAR 2011 and ICDAR 2013

Analysis on Damage and Mechanical Properties of Ballastless Track in a Tunnel after a Fire

In order to explore the damage and mechanical properties of ballastless track after a fire, the uniaxial compressive strength, shear strength, peak strain, and elastic modulus changes due to temperature were obtained through uniaxial compressive and shear tests of concrete after exposure to high temperatures. The test results showed that with increases in temperature, the uniaxial compressive strength, shear strength, and elastic modulus of concrete all presented a decreasing trend, while the peak strain had an increasing trend. Then, based on the classical damage theory model and the strength probability distribution function of concrete micro-units, the high-temperature damage constitutive equation for concrete was established, and the compressive stress–strain curve of concrete after exposure to high temperature was reproduced. Finally, using the CFD numerical simulation software, the temperature field of a ballastless track structure in a tunnel during a fire was obtained, and the temperatures at different positions of ballastless track bed were acquired. Combined with the high-temperature damage constitutive equation for concrete deduced from tests and theoretical analysis, the strength and damage values of the ballastless track bed at different positions after a tunnel fire were obtained

Framework of our proposed algorithm.

<p>(<b>A</b>) Input image [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0182227#pone.0182227.ref053" target="_blank">53</a>]. (<b>B</b>) I-channel image in the PII color space. (<b>C</b>) H-channel image in the PII color space. (<b>D</b>) S-channel image in the PII color space. (<b>E</b>) Result of SE-MSER algorithm. (<b>F</b>) Strong text after CNN classification. (<b>G</b>) Weak text after CNN classification. (<b>H</b>) Recursive local search and duplicate removal. (<b>I</b>) Final result.</p

Evaluation of character-level recall on the ICDAR 2011 test set.

<p>(<b>A</b>) Original MSER on multiple channels. (<b>B</b>) Multiple MSERs comparison.</p

Experimental results on the ICDAR 2013 dataset.

<p>Experimental results on the ICDAR 2013 dataset.</p