Distributed Beamforming with Wirelessly Powered Relay Nodes

This paper studies a system where a set of $N$ relay nodes harvest energy from the signal received from a source to later utilize it when forwarding the source's data to a destination node via distributed beamforming. To this end, we derive (approximate) analytical expressions for the mean SNR at destination node when relays employ: i) time-switching based energy harvesting policy, ii) power-splitting based energy harvesting policy. The obtained results facilitate the study of the interplay between the energy harvesting parameters and the synchronization error, and their combined impact on mean SNR. Simulation results indicate that i) the derived approximate expressions are very accurate even for small $N$ (e.g., $N=15$), ii) time-switching policy by the relays outperforms power-splitting policy by at least $3$ dB.Comment: 4 pages, 3 figures, accepted for presentation at IEEE VTC 2017 Spring conferenc

Channel Impulse Response-based Distributed Physical Layer Authentication

In this preliminary work, we study the problem of {\it distributed} authentication in wireless networks. Specifically, we consider a system where multiple Bob (sensor) nodes listen to a channel and report their {\it correlated} measurements to a Fusion Center (FC) which makes the ultimate authentication decision. For the feature-based authentication at the FC, channel impulse response has been utilized as the device fingerprint. Additionally, the {\it correlated} measurements by the Bob nodes allow us to invoke Compressed sensing to significantly reduce the reporting overhead to the FC. Numerical results show that: i) the detection performance of the FC is superior to that of a single Bob-node, ii) compressed sensing leads to at least $20\%$ overhead reduction on the reporting channel at the expense of a small ($<1$ dB) SNR margin to achieve the same detection performance.Comment: 6 pages, 5 figures, accepted for presentation at IEEE VTC 2017 Sprin

Design and Simulation of Worldwide Interoperability for Microwave Access Computer Network for 3×3 Km Universal Sample of Building Campus

The aim of this study to design a wireless computer network of a particular network as a large-scale company or university to improve&nbsp;mobility and to let the teachers and students of the university, for example, stay interacted and connected at any time in any campus&nbsp;location or site. Therefore, This study needed to cover the overall area of this campus with efficient wireless coverage that exceeds the&nbsp;university boundaries to maintain wireless signal strength. To do that, the researchers thought that it is very significant to design a&nbsp;Worldwide Interoperability for Microwave Access (WiMax) computer network with the most powerful and advanced hardware component&nbsp;capabilities to full fit teachers’ and students’ requirements of fast net browsing and files’ download. After designing the university campus&nbsp;of computer network, simulation has done by OPNET 14 Modular to determine the WiMax network design parameters. The purpose&nbsp;of the current research is to find if the design of the campus network is efficient or not and also to determine the performance of theimplemented network

Adaptable Topology For Peer-To-Peer Live Video Streaming

Aliran video menjadi satu aplikasi yang penting yang digunakan melalui internet. Video streaming is one of the most important applications used over the internet

SYNTHESIS AND CHARACTERIZATION OF NEW COUMARIN DERIVATIVES CONTAINING VARIOUS MOIETIES WITH ANTIBACTERIAL ACTIVITIES

Objective: The purpose of this research is to evaluate the antibacterial activity of different moieties (Schiff bases, chalcones, hydrazones and hydrazinyl thiazole) derivatives, inserted at carbon 8 of 7-hydroxy-4-methyl coumarin, using in vitro, serial broth dilution method.Methods: A series of new coumarin derivatives, including (Schiff bases, chalcones, hydrazones and hydrazinyl thiazole), were prepared from 7-hydroxy-4-methyl coumarin, by insertion of the formyl group, at carbon number 8 using Duff reaction. The structure of the new synthesized derivatives elucidated and confirmed utilizing the corresponding analytical and spectroscopic data; including FT-IR, 13C-NMR, and mass spectroscopy. All new coumarin derivatives have been screened for their preliminary antibacterial activity, by serial broth dilution method against two Gram-positive bacteria (Staphylococcus epidermidis and Staphylococcus hemolyticus) and two Gram-negative bacteria (Escherichia coli and Klebsiella pneumoniae).Results: All the synthesized compounds have been found to exhibit considerable antibacterial activity in vitro. Among all the derivatives, compound (5a), showed the highest rate of inhibition, against (Escherichia coli), while compound (6a), showed the greatest anti-bacterial activity against (Staphylococcus hemolyticus), each with minimum inhibitory concentration of (25µg/ml), and the highest MIC of 200 µg/ml for compound 2, against. Klebsiella pneumoniae.Conclusion: Our results displayed a substantial preliminary antibacterial activity of the new coumarin moieties, especially some hydrazones and chalcones at C8 of the coumarin nucleus, against Gram-positive and a Gram-negative bacteria with distinguished MIC.Â

SYNTHESIS, ANTIMICROBIAL EVALUATION, DENSITY FUNCTIONAL THEORY, AND DOCKING STUDIES OF SOME NEW 2-MERCAPTO PYRIMIDINE SCHIFF BASES

Objective: Pyrimidine derivatives are reported to possess antibacterial, antifungal, anticancer, and anticonvulsant activities. Encouraged by this remarks, we decided to synthesize novel compounds of new 2-macraptopyrimidine linked to Schiffs̕ bases. Methods: The present work involves the synthesis of new 2-mercaptopyrimidine linked to Schiffs̕ bases. The starting, 2-mercaptopyrimidine, compound (1) reacted with thiourea to afford the corresponding 1-(pyrimidin-2-yl) thiourea (2). Then compound (2) was used as the key intermediate to prepare the -1-(2-hydroxy benzylidene)-3-(pyrimidin-2-yl) thiourea (3), and (1-benzylidine)-3-(pyrimidin-2-yl) thiourea (4), through the reaction with 2-hydroxybenzaldehyde, and benzaldehyde, respectively. Results: All the synthesized compounds were characterized by Fourier-transform infrared and1H-nuclear magnetic resonance spectroscopy. The synthesized derivatives were screened for their in vitro, antibacterial activity against two Gram-positive bacteria: Bacillus subtilis and Staphylococcus aureus and four Gram-negative bacteria: Klebsiella pneumoniae, Escherichia coli, and Salmonella typhi, and the results showed that most of them have good antibacterial activity. While their antifungal activity against three fungi species (Aspergillus fumigates, Aspergillus niger, Aspergillus terrus and Rhizopus) revealed that compounds (2-4) displayed the most potent antifungal activity. Density functional theory (DFT) calculations for the synthesized 2-mercapto pyrimidine derivatives were conducted, using a molecular structure with optimized geometry. Highest occupied molecular orbital/lowest unoccupied molecular orbital energies and structures are demonstrated. Conclusion: The antimicrobial activity indicates that compounds (3) and (4) are the most active than the compounds (1) and (2). Molecular docking revealed that compounds (3) and (4), with bulky phenyl groups are essential to blocking the active centers of glucose -6-phosphate synthase in the bacteria and fungi

Interconnects architectures for many-core era using surface-wave communication

PhD ThesisNetworks-on-chip (NoCs) is a communication paradigm that has emerged aiming to address on-chip communication challenges and to satisfy interconnection demands for chip-multiprocessors (CMPs). Nonetheless, there is continuous demand for even higher computational power, which is leading to a relentless downscaling of CMOS technology to enable the integration of many-cores. However, technology downscaling is in favour of the gate nodes over wires in terms of latency and power consumption. Consequently, this has led to the era of many-core processors where power consumption and performance are governed by inter-core communications rather than core computation. Therefore, NoCs need to evolve from being merely metalbased implementations which threaten to be a performance and power bottleneck for many-core efficiency and scalability. To overcome such intensified inter-core communication challenges, this thesis proposes a novel interconnect technology: the surface-wave interconnect (SWI). This new RF-based on-chip interconnect has notable characteristics compared to cutting-edge on-chip interconnects in terms of CMOS compatibility, high speed signal propagation, low power dissipation, and massive signal fan-out. Nonetheless, the realization of the SWI requires investigations at different levels of abstraction, such as the device integration and RF engineering levels. The aim of this thesis is to address the networking and system level challenges and highlight the potential of this interconnect. This should encourage further research at other levels of abstraction. Two specific system-level challenges crucial in future many-core systems are tackled in this study, which are cross-the-chip global communication and one-to-many communication. This thesis makes four major contributions towards this aim. The first is reducing the NoC average-hop count, which would otherwise increase packet-latency exponentially, by proposing a novel hybrid interconnect architecture. This hybrid architecture can not only utilize both regular metal-wire and SWI, but also exploits merits of both bus and NoC architectures in terms of connectivity compared to other general-purpose on-chip interconnect architectures. The second contribution addresses global communication issues by developing a distance-based weighted-round-robin arbitration (DWA) algorithm. This technique prioritizes global communication to be send via SWI short-cuts, which offer more efficient power dissipation and faster across-the-chip signal propagation. Results obtained using a cycleaccurate simulator demonstrate the effectiveness of the proposed system architecture in terms of significant power reduction, considervii able average delay reduction and higher throughput compared to a regular NoC. The third contribution is in handling multicast communications, which are normally associated with traffic overload, hotspots and deadlocks and therefore increase, by an order of magnitude the power consumption and latency. This has been achieved by proposing a novel routing and centralized arbitration schemes that exploits the SWI0s remarkable fan-out features. The evaluation demonstrates drastic improvements in the effectiveness of the proposed architecture in terms of power consumption ( 2-10x) and performance ( 22x) but with negligible hardware overheads ( 2%). The fourth contribution is to further explore multicast contention handling in a flexible decentralized manner, where original techniques such as stretch-multicast and ID-tagging flow control have been developed. A comparison of these techniques shows that the decentralized approach is superior to the centralized approach with low traffic loads, while the latter outperforms the former near and after NoC saturation

Glaucoma and Corneal Transplant Procedures

Glaucoma after corneal transplantation is a leading cause of ocular morbidity after penetrating keratoplasty. The incidence reported is highly variable and a number of etiologic factors have been identified. A number of treatment options are available; surgical intervention for IOP control is associated with a high incidence of graft failure. IOP elevation is less frequently seen following deep anterior lamellar keratoplasty. Descemet's striping-automated endothelial keratoplasty is also associated with postprocedure intraocular pressure elevation and secondary glaucoma and presents unique surgical challenges in patients with preexisting glaucoma surgeries. Glaucoma exists in up to three-quarters of patients who undergo keratoprosthesis surgery and the management if often challenging. The aim of this paper is to highlight the incidence, etiology, and management of glaucoma following different corneal transplant procedures. It also focuses on the challenges in the diagnosis of glaucoma and intraocular pressure monitoring in this group of patients

Mutational analysis of CYP1B1 gene in Pakistani pediatric patients affected with Primary Congenital Glaucoma

Background: Glaucoma is the significant cause of blindness all over the world. Primary congenital glaucoma (PCG) reduces the vision and ultimately causes the blindness by damaging the aqueous drainage system of the eye. The purpose of the current study was to determine the pathogenic mutations in the CYP1B1 gene responsible for PCG.Methods: A total of thirty-five PCG patients were enrolled in this study. Blood samples were collected from the enrolled patients, and after DNA extraction and amplification, the coding regions of CYP1B1 were sequenced to determine the pathogenic mutations. In-silico analysis of the identified mutation was executed to study the effect of genetic variation on protein structure.Results: One mutation, c.1169 G>A has been revealed in exon 3 of the CYP1B1 gene leading to p.R390H, present in 20% of the patients enrolled. Besides, two missense sequence variants c.1294G>C (2 patients), c.1358A>G (4 patients) and a synonymous variant c.1347T>C (18 patients) has also been observed.Conclusion: Our study not only reaffirms the role of CYP1B1 mutations in PCG but also supports the use of genetic screening for molecular diagnosis and carrier identification, which will reduce the burden of disease on society. Furthermore, the in-silico analysis of the identified mutations provided an in-depth understanding of the PCG pathogenesis at the molecular level.Keywords: Primary congenital glaucoma; CYP1B1, mutation; Genetic variatio

Outcomes of Multi-Trauma Road Traffic Crashes at a Tertiary Hospital in Oman : Does attendance by trauma surgeons versus non-trauma surgeons make a difference?

Objectives: Trauma surgeons are essential in hospital-based trauma care systems. However, there are limited data regarding the impact of their presence on the outcome of multi-trauma patients. This study aimed to assess the outcomes of multi-trauma road traffic crash (RTC) cases attended by trauma surgeons versus those attended by non-trauma surgeons at a tertiary hospital in Oman. Methods: This retrospective study was conducted in December 2015. A previously published cohort of 821 multi-trauma RTC patients admitted between January and December 2011 to the Sultan Qaboos University Hospital, Muscat, Oman, were reviewed for demographic, injury and hospitalisation data. In-hospital mortality constituted the main outcome, with admission to the intensive care unit, operative management, intubation and length of stay constituting secondary outcomes. Results: A total of 821 multi-trauma RTC cases were identified; of these, 60 (7.3%) were attended by trauma surgeons. There was no significant difference in mortality between the two groups (P = 0.35). However, patients attended by trauma surgeons were significantly more likely to be intubated, admitted to the ICU and undergo operative interventions (P &lt;0.01 each). The average length of hospital stay in both groups was similar (2.6 versus 2.8 days; P = 0.81). Conclusion: No difference in mortality was observed between multi-trauma RTC patients attended by trauma surgeons in comparison to those cared for by non-trauma surgeons at a tertiary centre in Oman