Remote sensing of solar radiation absorbed and reflected byvegetated land surfaces

The problem of remotely sensing the amount of solar radiation absorbed and reflected by vegetated land surfaces was investigated with the aid of one- and three-dimensional radiative transfer models. Desert vegetation was modeled as clumps of leaves randomly distributed on a bright dry soil with a ground cover of generally less than 100%. Surface albedo (ALB), fraction of photosynthetically active radiation absorbed by the canopy (FAPAR), fractions of solar radiation absorbed by the canopy (FASOLAR) and soil (FASOIL), and normalized difference vegetation index (NDVI) were calculated for various illumination conditions. The magnitude of errors involved in the estimation of surface albedo from broadband monodirectional measurements was assessed. The nature of the relationships between NDVI vs. FASOLAR, FAPAR, FASOIL, and ALB and their sensitivity to all problem parameters were investigated in order to develop simple predictive models. The relationship between NDVI measured above the atmosphere and that sensed above the canopy at the ground surface was studied to characterize atmospheric effects     

Big Data 2.0 Processing Systems: Taxonomy and Open Challenges

Data is key resource in the modern world. Big data has become a popular term which is used to describe the exponential growth and availability of data. In practice, the growing demand for large-scale data processing and data analysis applications spurred the development of novel solutions from both the industry and academia. For a decade, the MapReduce framework, and its open source realization, Hadoop, has emerged as a highly successful framework that has created a lot of momentum in both the research and industrial communities such that it has become the defacto standard of big data processing platforms. However, in recent years, academia and industry have started to recognize the limitations of the Hadoop framework in several application domains and big data processing scenarios such as large scale processing of structured data, graph data and streaming data. Thus, we have witnessed an unprecedented interest to tackle these challenges with new solutions which constituted a new wave of mostly domain-specific, optimized big data processing platforms. In this article, we refer to this new wave of systems as Big Data 2.0 processing systems. To better understand the latest ongoing developments in the world of big data processing systems, we provide a taxonomy and detailed analysis of the state-of-the-art in this domain. In addition, we identify a set of the current open research challenges and discuss some promising directions for future research.     

Synthesis of ZnO/Fe3 O4 /rGO nanocomposites and evaluation of antibacterial activities towards E. coli and S. aureus

Antibacterial activity of nanoparticles (NPs) and nanocomposites (NCs) has received wide spread attention in biomedical applications. In this direction, the authors prepared zinc oxide (ZnO), iron oxide (Fe₃ O₄), and their composite including reduced graphene oxide (rGO) by hydrothermal method. The structural and microstructural properties of the synthesised NPs and NCs were investigated by XRD, FT‐IR, UV‐Vis, TGA, and TEM analysis. PEG‐coated ZnO and Fe₃ O₄ form in hexagonal wurtzite and inverse spinel structures, respectively. ZnO forms in rod‐shaped (aspect ratio of ∼3) morphology, whereas well‐dispersed spherical‐shaped morphology of ∼10 nm is observed in Fe₃ O₄ NPs. The ZnO/Fe₃ O₄ composite possesses a homogeneous distribution of above two phases and shows a very good colloidal stability in aqueous solvent. These synthesised particles exhibited varying antibacterial activity against gram‐positive strain Staphylococcus aureus (S. aureus) and gram‐negative strain Escherichia coli (E. coli). The nanocomposite exhibits a better cidal effect on E. coli when compared to S. aureus when treated with 1 mg/ml concentration. Further, the addition of rGO has intensified the anti‐bacterial effect to a much higher extent due to synergistic influence of individual components.Inspec keywords: colloids, visible spectra, II‐VI semiconductors, thermal analysis, nanofabrication, X‐ray diffraction, nanoparticles, biomedical materials, wide band gap semiconductors, transmission electron microscopy, ultraviolet spectra, antibacterial activity, nanocomposites, zinc compounds, nanobiotechnology, Fourier transform infrared spectra, graphene compounds, iron compounds, crystal growth from solution, crystal morphologyOther keywords: antibacterial activity, E. coli, biomedical applications, iron oxide, hydrothermal method, structural properties, microstructural properties, PEG‐coated ZnO, hexagonal wurtzite, inverse spinel structures, gram‐positive strain Staphylococcus aureus, S. aureus, gram‐negative strain Escherichia coli, nanocomposites, nanoparticles, XRD, FTIR spectra, UV‐vis spectra, TGA, TEM, rod‐shaped morphology, spherical‐shaped morphology, colloidal stability, cidal effect, ZnO‐Fe₃ O₄ ‐CO     

Adaptive Chip-Level Channel Estimation for IMT-DS System: DL and UL

In this paper, chip-level adaptive channel estimation has been explored by using LMS algorithm for wideband CDMA channel estimation. The expression for the optimum step-size is modified for fading channel estimation problem. In addition, a new method is proposed to obtain channel estimates with known pilot symbols which is found to give better results than other methods. For slow fading channels, like pedestrian channel, LMS estimator with no update mode is found to give satisfactory results. For fast fading channels, like vehicular channel, a common decision directed technique of channel estimation is modified to be used at chip-level in the downlink (DL). A novel despreader-respreader based channel estimator has been proposed to obtain uplink channel estimates at chip level which resolves the deficiencies of conventional methods. The performance of Rake receiver with proposed channel estimation schemes for IMT-DS system – a 3G mobile communication standard – is evaluated in terms of BER. S. Faisal A. Shah received the B.S. degree from NED University of Engineering and Technology, Karachi, Pakistan, in 1998 and the M.S. degree from King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia, in 2001, both in Electrical Engineering. From 2001 to 2004, he was a Lecturer in Electrical & Electronics Engineering Department, University of Sharjah, UAE. In September 2004, he joined the Electrical and Computer Engineering Department of University of Minnesota, USA, as a research assistant where he is currently pursuing the Ph.D. degree in Electrical Engineering. His research interests include ultra-wideband communication systems, adaptive signal processing and its application to wireless communication systems. Asrar U.H. Sheikh graduated from the University of Engineering and Technology, Lahore, Pakistan with first class honours and received his M.Sc. and Ph.D. degrees from the University of Birmingham, England, in 1966 and 1969 respectively. After completing teaching assignments in several countries, he returned to Birmingham as a Research Fellow in 1975. He worked at Carleton University from 1981 to 1997, first as Associate Professor and later as a Professor and Associate Chairman for Graduate Studies. He was the Founder Director of PCS Research Laboratory at Carleton University. Before taking position of Bugshan/Bell Lab Chair in Telecommunications at King Fahd University of Petroleum and Minerals in April 2000, he was a Professor and Associate Head of the Department of Electronic and Information Engineering at Hong Kong Polytechnic University, where he was founding director of Wireless Information Systems Research (WISR) Centre. At KFUPM he established Telecommunications Research Laboratory. Professor Sheikh is the author of a recently published book, Wireless Communications - Theory & Techniques published by Kluwer Academic Publishers, Orwell, Mass., USA. He has published over 230 papers in international journals and conference proceedings. He also authored or co-authored 30 technical reports. Dr. Sheikh is a co-recipient of Paul Adorian Premium from IERE (London) for his work on impulsive noise characterization. He was awarded teaching achievement awards in 1984 and 1986, and Research Achievement Award in 1994, all by Carleton University. Dr. Sheikh is actively involved in several international conferences mainly as a member of Technical Program Committees. He has organized and chaired many technical sessions at several international conferences. He Chaired the Technical Program of VTC'98. He is an editor of IEEE Transaction on Wireless Communications, a Technical Associate Editor of IEEE Communication Magazine. He is on the Editorial Board of Wireless Personal Communications, and Wireless Communications and Mobile Computing. He was a co-guest editor of the Special Issue of WPC on Interference. Dr. Sheikh is also on the reviewer panels of many IEEE and IEE Transactions and Journals. Dr. Sheikh has been consultant to many private companies and government agencies. His current interests are in signal processing in communications, mitigation of interference, spread spectrum and 3G and beyond systems. His other interests include helping developing countries in education and research. He had assignments under UNDP's sustained Development Program. He is a Fellow of the IEEE and a Fellow of the IEE. Dr. Sheikh is listed in Marquis Who's Whos in the world and Who's Who in Science and Engineering.