Smart Antennas and Intelligent Sensors Based Systems: Enabling Technologies and Applications

open access articleThe growing communication and computing capabilities in the devices enlarge the connected world and improve the human life comfort level. The evolution of intelligent sensor networks and smart antennas has led to the development of smart devices and systems for real-time monitoring of various environments. The demand of smart antennas and intelligent sensors significantly increases when dealing with multiuser communication system that needs to be adaptive, especially in unknown adverse environment [1–3]. The smart antennas based arrays are capable of steering the main beam in any desired direction while placing nulls in the unwanted directions. Intelligent sensor networks integration with smart antennas will provide algorithms and interesting application to collect various data of environment to make intelligent decisions [4, 5]. The aim of this special issue is to provide an inclusive vision on the current research in the area of intelligent sensors and smart antenna based systems for enabling various applications and technologies. We cordially invite some researchers to contribute papers that discuss the issues arising in intelligent sensors and smart antenna based system. Hence, this special issue offers the state-of-the-art research in this field

Evaluation of Wear Properties of Flyash and C-Glass Reinforced Al4046 Hybrid MMC

Metal Matrix Composites (MMCs) are engineered materials designed by a combination of a particulate or fibre reinforced in a metal or alloy matrix. This research work is concerned about the production of Fly ash, C-glass reinforced hybrid Aluminium 4046 metal matrix composites and further to investigate on the wear properties of the processed composites. Aluminium4046-Flyash-C-glass metal matrix composites have been processed for this study. In this work, the experimental study began with mixing of Aluminium powder, Fly ash particulates and C-glass fibers using a Stir casting technique at different weight fraction addition of Fly ash(2%,4%,6%) and Cglass(1%,3%,5%,7%).After production, the machining of the hybrid metal matrix composites is carried out as per ASTM standards. The wear rate is calculated using Pin on disc test machine. This experiment result show that best wear resistant combination is at 6% of Fly ash and 7% of C-glass is used

Regulating urban upgrading in developing countries

Drawing on a four-year research programme conducted in Sri Lanka (part of a larger programme also conducted in India and Kenya) this paper addresses the issue of building and planning regulations and how such regulations affect people’s livelihoods. This paper begins by reviewing the urban housing programmes undertaken in Sri Lanka over the past 30 years with special reference to urban upgrading projects and their respective planning and building regulations. The authors have analysed four cases from Colombo Municipality and two cases from a secondary town, Moratuwa Municipality in Colombo Municipal Authority, in order to assess the impacts of such urban upgrading programmes on the livelihoods of the poor; some conclusions and recommendations have been drawn. Guidance notes (based on a literature review, historical analysis and case studies) are presented towards the end of the paper for the use of local government staff as well as others acting as partners in the improvement of livelihoods in urban areas. Land reforms and land management are key components of any sustainable urban upgrading programme. The authors conclude that regulatory frameworks which take into account existing patterns (with the exception of unsafe practices) of livelihoods and socio-economic aspirations will enhance the potential for sustainable livelihoods

The stability of Killing-Cauchy horizons in colliding plane wave space-times

It is confirmed rigorously that the Killing-Cauchy horizons, which sometimes occur in space-times representing the collision and subsequent interaction of plane gravitational waves in a Minkowski background, are unstable with respect to bounded perturbations of the initial waves, at least for the case in which the initial waves have constant aligned polarizations.Comment: 8 pages. To appear in Gen. Rel. Gra

On realistic target coverage by autonomous drones

Low-cost mini-drones with advanced sensing and maneuverability enable a new class of intelligent sensing systems. To achieve the full potential of such drones, it is necessary to develop new enhanced formulations of both common and emerging sensing scenarios. Namely, several fundamental challenges in visual sensing are yet to be solved including (1) fitting sizable targets in camera frames; (2) positioning cameras at effective viewpoints matching target poses; and (3) accounting for occlusion by elements in the environment, including other targets. In this article, we introduce Argus, an autonomous system that utilizes drones to collect target information incrementally through a two-tier architecture. To tackle the stated challenges, Argus employs a novel geometric model that captures both target shapes and coverage constraints. Recognizing drones as the scarcest resource, Argus aims to minimize the number of drones required to cover a set of targets. We prove this problem is NP-hard, and even hard to approximate, before deriving a best-possible approximation algorithm along with a competitive sampling heuristic which runs up to 100× faster according to large-scale simulations. To test Argus in action, we demonstrate and analyze its performance on a prototype implementation. Finally, we present a number of extensions to accommodate more application requirements and highlight some open problems

Screening Potato Varieties for Cultivation in Arid Regions: Effect of Planting Date on Emergence of Imported and Locally-Produced Seeds

Potato is new as a major crop in arid regions. Due to its food value, expanding production and increasing consumer demand, it is being considered as a strategic crop. Production is based on yearly import of seed potatoes from Europe. Productivity of potato could be increased by targeted selection of varieties for local adaptation, by choosing the adequate conditions for planting and through proper seed management. The seed and its imposed planting time were found to be incompatible with optimum stand development for the crop, resulting in a loss of potential yield. The young physiological age and persisting dormancy of seed prevented early emergence of sprouts from a mid-November planting time. When planted on 11 consecutive dates, varieties showed a significant improvement of emergence rates with delayed planting time. Emergence rate doubled as planting was delayed from mid November to mid December. Emergence rate results for imported tubers were confirmed over three consecutive growing seasons and contrast with emergence data for locally produced seed planted at the same or earlier dates

Black holes from high-energy beam--beam collisions

Using a recent technique, proposed by Eardley and Giddings, we extend their results to the high-energy collision of two beams of massless particles, i.e. of two finite-front shock waves. Closed (marginally) trapped surfaces can be determined analytically in several cases even for collisions at non-vanishing impact parameter in D\ge 4 space-time dimensions. We are able to confirm and extend earlier conjectures by Yurtsever, and to deal with arbitrary axisymmetric profiles, including an amusing case of ``fractal'' beams. We finally discuss some implications of our results in high-energy experiments and in cosmology.Comment: 17 pages Revtex, 1 figure, references adde