Joint Optimization of Power and Location in Full-Duplex UAV Enabled Systems

Unmanned aerial vehicles (UAVs) can be used as aerial base stations (BSs) for future small cells. They can increase the spectral efficiency of the small cells due to their higher probability to have line-of-sight (LOS) connections and their mobility as a BS. In this article, in order to show the effectiveness of using full-duplex (FD) technology in UAV networks, we consider a UAV equipped with FD technology (FD-UAV) with imperfect self-interference cancelation as an aerial BS that serves both uplink (UL) and downlink (DL) users simultaneously in a small cell network. We aim to maximize DL sum-rate, whilst prescribing a certain quality of service for UL users, by optimizing the location of FD-UAV and available resources. The problem is nonconvex; so we propose an iterative method by exploiting the difference of convex functions programming to jointly optimize transmission power of users, FD-UAV location, and FD-UAV transmission power. Simulation results are illustrated to show the effectiveness of the proposed method for FD-UAV in comparison with ground BS, in both FD and half-duplex modes

Resource Allocation in Full-Duplex UAV Enabled Multi Small Cell Networks

Flying platforms such as Unmanned Aerial Vehicles (UAVs) are a promising solution for future small cell networks. UAVs can be used as aerial Base Stations (BSs) to enhance coverage, capacity and reliability of wireless networks. Also, with recent advances of Self Interference Cancellation (SIC) techniques in Full-Duplex (FD) systems, practical implementation of FD BSs is feasible. In this paper, we investigate the problem of resource allocation for multi-small cell networks with FD-UAVs as aerial BSs with imperfect SIC. We consider three different scenarios: a) maximizing the DL sum-rate, b) maximizing the UL sum-rate, and finally c) maximizing the sum of UL and DL sum-rates. The aforementioned problems result in non-convex optimization problems, therefore, successive convex approximation algorithms are developed by leveraging D.C. (Difference of Convex functions) programming to find sub-optimal solutions. Simulation results illustrated validity and effectiveness of the proposed radio resource management algorithms in comparison with ground BSs, in both FD mode and its half-duplex (HD) counterpart. The results also indicate those situations where using aerial BS is advantageous over ground BS and reveal how FD transmission enhances the network performance in comparison with HD one

Exogenous spatial precuing reliably modulates object processing but not object substitution masking

Object substitution masking (OSM) is used in behavioral and imaging studies to investigate processes associated with the formation of a conscious percept. Reportedly, OSM occurs only when visual attention is diffusely spread over a search display or focused away from the target location. Indeed, the presumed role of spatial attention is central to theoretical accounts of OSM and of visual processing more generally (Di Lollo, Enns, & Rensink, Journal of Experimental Psychology: General 129:481–507, 2000). We report a series of five experiments in which valid spatial precuing is shown to enhance the ability of participants to accurately report a target but, in most cases, without affecting OSM. In only one experiment (Experiment 5) was a significant effect of precuing observed on masking. This is in contrast to the reliable effect shown across all five experiments in which precuing improved overall performance. The results are convergent with recent findings from Argyropoulos, Gellatly, and Pilling (Journal of Experimental Psychology: Human Perception and Performance 39:646–661, 2013), which show that OSM is independent of the number of distractor items in a display. Our results demonstrate that OSM can operate independently of focal attention. Previous claims of the strong interrelationship between OSM and spatial attention are likely to have arisen from ceiling or floor artifacts that restricted measurable performance

Demographic features and antibiotic resistance among children hospitalized for urinary tract infection in northwest Iran

Ziaaedin Ghorashi1, Sona Ghorashi2, Hassan Soltani-Ahari1, Nariman Nezami3 1Department of Pediatrics, Tabriz University of Medical Sciences, 2Young Researchers Club, Tabriz Branch, Tabriz Islamic Azad University, 3Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran Introduction: Urinary tract infection (UTI) is the most common serious bacterial infection during infancy. The aim of the present study was to evaluate demographic characteristics, clinical presentations and findings, and antimicrobial resistance among infants and children hospitalized in Tabriz Children's Hospital, Tabriz, Iran. Methods: In this descriptive observational study, 100 children who had been admitted with UTI diagnosis to Tabriz Children's Hospital from March 2003 to March 2008 were studied. Demographic characteristics, chief complaints, clinical presentations and findings, urine analysis and cultures, antimicrobial resistance, and sonographic and voiding cystourethrographic reports were evaluated. Results: The mean age of patients was 35.77 ± 39.86 months. The male to female ratio was 0.26. The mean white blood cell count was 12,900 ± 5226/mm3. Sixty-two percent of patients had leukocytosis. The most common isolated pathogen was Escherichia coli spp (77%) followed by Klebsiella spp (10%), Enterobacter spp (9%), and Enterococcus spp (4%). Isolated pathogens were highly resistant to ampicillin, cotrimoxazole, and cephalexin (71%–96%), intermediate sensitivity to third-generation cephalosporins, and highly sensitive to ciprofloxacin (84.4%), amikacin (83.8%), and nitrofurantoin (82.8%). Conclusion: The most common pathogen of UTI in the hospitalized children was E. coli spp. The isolated pathogens were extremely resistant to ampicillin, and highly sensitive to ciprofloxacin and amikacin. Keywords: urinary tract infection, antibiotic, resistance, sensitivity, Escherichia col

Van small talk naar een waardevolle buurtgemeenschap

Light communities ontstaan doordat mensen samen gemeenschappelijke problemen willen oplossen. Sociologen Halleh Ghorashi, Baukje Reitsma en Zsuzsa Kovacs onderzochten de betekenis van de Amsterdamse community Meevaart. De zeer diverse bewoners blijken via small talk betekenisvolle contacten aan te gaan die hun horizon verruimen

Failure and Side Effects of Contraceptive Pills Used for Postponement of Menstrual Bleeding in Hajj Pilgrims of Kerman, 2000

Introduction: Use of contraceptive pills for postponement of menstruation has been a common practice for women traveling to the holy city of Mecca, although the side effects of this practice has not yet been studied. This research was carried out for determining the type and the prevalence of side effects of the contraceptive pills and for finding out the best type of regimens with least side effects in Hajj pilgrims from Kerman in 2001 Materials & Methods: In this research, 224 pilgrims were selected with similar backgrounds. A two part questionnaire was given to them during the last days of their pilgrimage. The first part was completed in the holy land of Arafat and the second part was answered two months later via telephone calls or postal service. Results: Menstruation had occurred in 2.1% of cases, 13.6% had experienced spotting, 19.5% nausea and in 11.4%, dizziness was reported. 81.1% had not experienced any side effects. 49.5% experienced normal bleeding during the first menstruation, while 66.1% had normal bleeding during the second menstruation. The rest had experienced either decreased or increased bleeding. 24.6% in the first menstruation and 20% in the second menstruation had experienced unusual pain. In 73% of the cases, the second menstruation had been normal. 2 tests showed a significant relation between the number of pills and duration of bleeding in the first menstruation (p=0.04%) and the second menstruation (p=0.03%). Conclusion: As the number and severity of side effects increase with an increase in dosage, it is recommended that lower dosages of pills should be used as far as possible. Also, since early start of pills does not decrease spotting, it is better if pills are started just a few days before the expected time of menstruation