A multivariant secure framework for smart mobile health application

This is an accepted manuscript of an article published by Wiley in Transactions on Emerging Telecommunications Technologies, available online: https://doi.org/10.1002/ett.3684 The accepted version of the publication may differ from the final published version.Wireless sensor network enables remote connectivity of technological devices such as smart mobile with the internet. Due to its low cost as well as easy availability of data sharing and accessing devices, the Internet of Things (IoT) has grown exponentially during the past few years. The availability of these devices plays a remarkable role in the new era of mHealth. In mHealth, the sensors generate enormous amounts of data and the context-aware computing has proven to collect and manage the data. The context aware computing is a new domain to be aware of context of involved devices. The context-aware computing is playing a very significant part in the development of smart mobile health applications to monitor the health of patients more efficiently. Security is one of the key challenges in IoT-based mHealth application development. The wireless nature of IoT devices motivates attackers to attack on application; these vulnerable attacks can be denial of service attack, sinkhole attack, and select forwarding attack. These attacks lead intruders to disrupt the application's functionality, data packet drops to malicious end and changes the route of data and forwards the data packet to other location. There is a need to timely detect and prevent these threats in mobile health applications. Existing work includes many security frameworks to secure the mobile health applications but all have some drawbacks. This paper presents existing frameworks, the impact of threats on applications, on information, and different security levels. From this line of research, we propose a security framework with two algorithms, ie, (i) patient priority autonomous call and (ii) location distance based switch, for mobile health applications and make a comparative analysis of the proposed framework with the existing ones.Published onlin

Can traditional forest management buffer forest depletion ? Dynamics of Moroccan High Atlas Mountain forests using remote sensing and vegetation analysis

On the south shore of the western Mediterranean Basin, mountain forest ecosystems are degraded, mainly due to their overexploitation. Topographic, edaphic and climatic conditions create stressful growing conditions and sensitive ecosystems. Nonetheless, in these ecosystems, forests remain an important resource for the subsistence of local populations. Historically the vulnerability of this resource has prompted mankind to establish traditional control forms of forest and pastoral areas. These common resource management systems are still functioning in the Moroccan High Atlas Mountains under the name of agdal which refers to the territory, the resources and access rules laid down by the local population in order to manage the territory. The estimation of land cover changes was a suitable method to evaluate the effectiveness of these community-based systems for forest conservation. In this paper we highlight the impact of this traditional management on woodland dynamics in a mountainous area (Nit Bouguemez Valley) through the use of remote sensing approaches, associated with forest structure characterisation and the analysis of social mechanisms. A diachronic analysis based on the comparison of aerial photographs (dated 1964) with a recent Spot 5 satellite image (from 2002, 2.5 m resolution) was performed. Estimation of changes in canopy cover percentage was achieved using a graphic chart as a base for the photo-interpretation, and a subsequent validation by field sampling. A map of canopy cover changes between 1964 and 2002 was produced. Ecological measurements of trees were also achieved on field plots. The results indicate that in the past 38 years, forest ecosystems have been affected by a relative decrease of 20.7% of the total forest area, and 8.7% for the mean canopy cover percentage. However, strong disparities in forest dynamics arose according to the agdal or non-agdal status of the forest. Significant progression in canopy cover is noted in controlled agdal areas but large degradation has occurred outside. Regarding the stand ecological conditions, we observed significant differences in the stand structure, according to the management mode. We suggest through this study increased recognition of customary forest regulations, which may be adapted and extrapolated to other communities. However, from an ecological point of view, the agdal system alone is not sufficient to reach a viable management mode in the long term

Compressed sensing techniques for receiver based post-compensation of transmitter's nonlinear distortions in OFDM systems

In this paper, compressed sensing techniques are proposed to linearize commercial power amplifiers driven by orthogonal frequency division multiplexing signals. The nonlinear distortion is considered as a sparse phenomenon in the time-domain, and three compressed sensing based algorithms are presented to estimate and compensate for these distortions at the receiver using a few and, at times, even no frequency-domain free carriers (i.e. pilot carriers). The first technique is a conventional compressed sensing approach, while the second incorporates a priori information about the distortions to enhance the estimation. Finally, the third technique involves an iterative data-aided algorithm that does not require any pilot carriers and hence allows the system to work at maximum bandwidth efficiency. The performances of all the proposed techniques are evaluated on a commercial power amplifier and compared. The error vector magnitude and symbol error rate results show the ability of compressed sensing to compensate for the amplifier's nonlinear distortions. (C) 2013 Elsevier B.V. All rights reserved

Experiments and Modeling of Fatigue Behavior of Friction Stir Welded Aluminum Lithium Alloy

An extensive experimental and computational investigation of the fatigue behavior of friction stir welding (FSW) of aluminum–lithium alloy (AA2099) is presented. In this study, friction stir butt welds were created by joining AA2099 using two different welding parameter sets. After FSW, microstructure characterization was carried out using microhardness testing, scanning electron microscopy, and transmission electron microscopy techniques. In particular, the metastable strengthening precipitates T1 (Al2CuLi) and δ’(Al3Li) seen in the base metal were observed to coarsen and dissolve due to the FSW process. In order to evaluate the static and fatigue behavior of the FSW of the AA2099, monotonic tensile and fully-reversed strain-controlled fatigue testing were performed. Mechanical testing of the FSW specimens found a decrease in the ultimate tensile strength and fatigue life compared to the base metal. While the process parameters had an effect on the monotonic properties, no significant difference was observed in the number of cycles to failure between the FSW parameters explored in this study. Furthermore, post-mortem fractography analysis of the FSW specimens displayed crack deflection, transgranular fracture, and delamination failure features commonly observed in other parent Al–Li alloys. Lastly, a microstructurally-sensitive fatigue model was used to elucidate the influence of the FSW process on fatigue life based on variations in grain size, microhardness, and particle size in the AA2099 FSW