Correction to: Cloud-based vehicular networks: a taxonomy,survey, and conceptual hybrid architecture

Wireless Networks - The original version of this article unfortunately contained a mistake in the title. The correct title has been published with this erratum.     

Effect of specimen size and loading conditions on spalling of concrete

Different qualities of concrete have been fire tested using different geometries of the specimens as well as different load levels and load configurations. The main objective with the study was to examine a test methodology consisting of a full‐scale test and different small scale‐tests for determining the probability of spalling and the amount of spalling of fire exposed concrete structures. A reference specimen was defined as a one‐sided fire exposed slab with the dimensions 1800 × 1200 mm² giving an exposed area of 1500 × 1200 mm². A number of concrete qualities with different probabilities for spalling, were tested using the reference specimen. These tests showed that the reference specimens worked well giving the expected test results. Small specimens were manufactured in different shapes with the same concrete as the one used in the reference tests. These small specimens were tested either at the same time as the reference specimens in the large furnace or afterwards on a small‐scale furnace where the fire exposed surface was 450 × 360 mm². The test results clearly show the increased probability and the increased amount of spalling by using external compressive loading. The results also show that by using pre‐stress through bars or wires the load can be lost due to heating of the bars/wires which results in a decreased amount of spalling. The boundary of the specimen also affects the amount of spalling. The spalling around the edges was in all tests less than the spalling on the central parts of the exposed area. It could also be noted that the spalling did not pass completely through any of the specimens. The reason for this is probably that the water/vapour could migrate out from the unexposed surface of the specimen. Copyright © 2006 John Wiley & Sons, Ltd.     

An Improvement Energy Consumption Policy Using Communication Reduction in Wireless Body Sensor Network

Dedicated short-range communications (DSRC) is an important wireless technology for current and future automotive safety and mitigation of traffic jams. In this work, we have designed a Coplanar waveguide microstrip patch antenna with linear, upper and bottom and side slots for application in DSRC. The patch antenna was designed using glass epoxy substrate (FR4). Various parametric analyses such as the current distribution, reflection coefficient, radiation pattern on E- and H-plane as well as the realized gain (dB) were performed. The results were obtained by simulation using high-frequency structure simulator tool. The proposed antenna covers a frequency band of 5.8–5.9 GHz which is highly dedicated to the DSRC wireless communication technology for enhancement of safety of the automotive transport system. The designed antenna shows a good return loss of ??19 dB at 5.9 GHz.The designed antenna shows a promising gain, return loss and radiation pattern for use in DSRC for automotive transport systems.

     

On the Mode II Fatigue Threshold for Mild Steel

This letter serves to report some fractographic observations and two different threshold values from Mode II fatigue tests conducted on sharply–notched bar specimens of mild steel using an increasing load technique. Thresholds for tensile mode growth and shear mode growth agree well with corresponding results from the literature. The presence or absence of residual stress influences the fatigue crack initiation and growth behaviour.     

Continuous operation of high-power (200 mW) strained-layerGa1-xInxAs/GaAs quantum-well lasers with emissionwavelengths 0.87⩽λ⩽0.95 μm

Separate confinement single-quantum-well lasers with 100-120 Å-thick strained Ga_1-xIn_xAs/GaAs active layers have been grown on (100) GaAs substrates by metalorganic chemical vapour deposition. Ten-stripe proton-implanted arrays with 90 μm-wide aperture and 250 μm cavity length emit 200 mW CW optical power at wavelengths 0.87⩽λ⩽0.95 μm. Lifetest data on an uncoated device emitting 90 mW/facet at 50°C and λ=0.95 μm suggest a mean-time-to-failure in excess of 2500 h at room temperature. The performance of lasers with strained Ga_1-xIn_xAs quantum wells is comparable to that of unstrained Al_xGa_1-xAs/GaAs quantum-well lasers without facet coating     

Limit and burst pressures for cylindrical shells with part-through slots

Pressure tests on aluminium alloy cylindrical shells having rectangular slots part through the wall thickness at mid-length were carried out to estimate plastic limit pressures for comparison with calculated lower bound limit pressures. The tests were continued to failure so that the results could be used in consideration of the ‘two criteria’ method of assessing the pressure carrying capacity of shells with defects. Twelve shells, nominally 5·5 in diameter and of different thicknesses, were tested. One had no slot, others had slots of different depths and side ratios.     

Explicit bounds for separation between Oseledets subspaces

We consider a two-sided sequence of bounded operators in a Banach space which are not necessarily injective and satisfy two properties (SVG) and (FI). The singular value gap (SVG) property says that two successive singular values of the cocycle at some index d admit a uniform exponential gap; the fast invertibility (FI) property says that the cocycle is uniformly invertible on the fastest d-dimensional direction. We prove the existence of a uniform equivariant splitting of the Banach space into a fast space of dimension d and a slow space of codimension d. We compute an explicit constant lower bound on the angle between these two spaces using solely the constants defining the properties (SVG) and (FI). We extend the results obtained by Bochi and Gourmelon in the finite-dimensional case for bijective operators and the results obtained by Blumenthal and Morris in the infinite dimensional case for injective norm-continuous cocycles, in the direction that the operators are not required to be globally injective, that no dynamical system is involved and no compactness of the underlying system or smoothness of the cocycle is required. Moreover we give quantitative estimates of the angle between the fast and slow spaces that are new even in the case of finite-dimensional bijective operators in Hilbert spaces.     

A privacy-preserving distributed transfer learning in activity recognition

Telecommunication Systems - Along with the widespread use of smartphones, activity recognition using embedded inertial sensors has intrigued researchers. The learning and employing activity...     

Could-based vehicular networks: a taxonomy,survey, and conceptual hybrid architecture

Wireless Networks - In recent times, vehicular network research has attracted the attention of both researchers and the industry partly due to its potential applications in efficient traffic...