Variability of geotechnical parameters of lateritic gravels overlying contrasted metamorphic rocks in a tropical humid area (Cameroon): implications for road construction

Bulletin of Engineering Geology and the Environment - The variability of the geotechnical properties of lateritic gravels developed on metamorphic rocks from the same clay protolith and of a nearby...     

Geological,geotechnical, and mechanical characterization of lateritic gravels from Eastern Cameroon for road construction purposes

Bulletin of Engineering Geology and the Environment - Petrographic, mineralogical (X-ray diffraction), and chemical analyses performed on granite-derived lateritic gravels of the...     

Multi-view region-adaptive multi-temporal DMM and RGB action recognition

Pattern Analysis and Applications - Human action recognition remains an important yet challenging task. This work proposes a novel action recognition system. It uses a novel multi-view...     

Hyper-resolution indoor channel impulse responses: multipathcomponents and k-factors

A hyper-resolution method has been used to estimate the wideband indoor channel impulse response at 1.3 GHz in a variety of environments within a building. The number of multipath components N and the Ricean k-factor have been investigated. The effect of the presence of people has also been monitored. The results show that if a 30 dB impulse response dynamic range threshold is considered. A value of N less than 7 is applicable to all cases for >90% of the time. It is also shown that the k-factor can be reliably estimated using only the three strongest components     

A robust multimedia surveillance system for people counting

Closed circuit television cameras (CCTV) are widely used in monitoring. This paper presents an intelligent CCTV crowd counting system based on two algorithms that estimate the density of each pixel in each frame and use it as a basis for counting people. One algorithm uses scale-invariant feature transform (SIFT) features and clustering to represent pixels of frames (SIFT algorithm) and the other uses features from accelerated segment test (FAST) corner points with SIFT features (SIFT-FAST algorithm). Each algorithm is designed using a novel combination of pixel-wise, motion-region, grid map, background segmentation using Gaussian mixture model (GMM) and edge detection. A fusion technique is proposed and used to validate the accuracy by combining the result of the algorithms at frame level. The proposed system is more practical than the state of the art regression methods because it is trained with a small number of frames so it is relatively easy to deploy. In addition, it reduces the training error, set-up time, cost and open the door to develop more accurate people detection methods. The University of California (UCSD) and Mall datasets have been used to test the proposed algorithms. The mean deviation error, mean squared error and the mean absolute error of the proposed system are less than 0.1, 16.5 and 3.1, respectively, for the Mall dataset and less than 0.07, 5.5 and 1.9, respectively, for UCSD dataset.

     

Short‐scale diversity in a dynamic rain fade environment

This article is concerned with using time‐varying uniformly spaced rainfall data to investigate the concept and values of instantaneous diversity gain. This has been obtained on a minute‐by‐minute basis in order to illustrate the behaviour of a VSAT communication system which switches to the most reliable link every minute. The simulations have been carried out using a whole year of rain data obtained from the recordings of a dense rain gauge network located in Barcelona. After illustrating the concept of instantaneous diversity gain, this paper shows the results obtained for various site separations and 20 GHz. These results have been plotted together with the values given by some long‐term‐based models. The comparison shows that such models are not appropriate for dynamic site diversity. This was found to increase the reliability of a VSAT system, especially under severe rain conditions in which the rainfall rates are spatially arranged in rain cells and the attenuation experienced by the two sites is strongly decorrelated. The correlation coefficient between the attenuation series calculated for several separation distances has also been obtained to illustrate this concept. Finally, the paper gives the attenuation distributions calculated for a VSAT system with and without site diversity and for several site separations. Copyright © 2005 John Wiley & Sons, Ltd.