755 research outputs found

    Wireless resource virtualization: opportunities, challenges, and solutions

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    Wireless resource virtualization (WRV) is currently emerging as a key technology to overcome the major challenges facing the mobile network operators (MNOs) such as reducing the capital, minimizing the operating expenses, improving the quality of service, and satisfying the growing demand for mobile services. Achieving such conflicting objectives simultaneously requires a highly efficient utilization of the available resources including the network infrastructure and the reserved spectrum. In this paper, the most dominant WRV frameworks are discussed where different levels of network infrastructure and spectrum resources are shared between multiple MNOs. Moreover, we summarize the major benefits and most pressing business challenges of deploying WRV. We further highlight the technical challenges and requirements for ion and sharing of spectrum resources in next generation networks. In addition, we provide guidelines for implementing comprehensive solutions that are able to and share the spectrum resources in next generation network. The paper also presents an efficient algorithm for base station virtualization in long‐term evolution (LTE) networks to share the wireless resources between MNOs who apply different scheduling polices. The proposed algorithm maintains a high‐level of isolation and offers throughput performance gain. Copyright © 2016 John Wiley & Sons, Ltd. Wireless resource virtualization (WRV) is emerging as a key technology to reduce cost and increase the total network capacity by sharing wireless resources between multiple mobile operators. In this paper, we present the concepts, highlight the benefits, and discuss the technical challenges and requirements for ion and sharing of WRV in next generation networks. Furthermore, an efficient WRV approach for long‐term evolution base stations is proposed and evaluated

    Betrayed by the Guardian: Security and Privacy Risks of Parental Control Solutions

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    For parents of young children and adolescents, the digital age has introduced many new challenges, including excessive screen time, inappropriate online content, cyber predators, and cyberbullying. To address these challenges, many parents rely on numerous parental control solutions on different platforms, including parental control network devices (e.g., WiFi routers) and software applications on mobile devices and laptops. While these parental control solutions may help digital parenting, they may also introduce serious security and privacy risks to children and parents, due to their elevated privileges and having access to a significant amount of privacy-sensitive data. In this paper, we present an experimental framework for systematically evaluating security and privacy issues in parental control software and hardware solutions. Using the developed framework, we provide the first comprehensive study of parental control tools on multiple platforms including network devices, Windows applications, Chrome extensions and Android apps. Our analysis uncovers pervasive security and privacy issues that can lead to leakage of private information, and/or allow an adversary to fully control the parental control solution, and thereby may directly aid cyberbullying and cyber predators

    Application of PSO to Design UPFC-based Stabilizers

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    Today, power demand grows rapidly and expansion in transmission and generation is restricted with the limited availability of resources and the strict environmental constraints. Consequently, power systems are today much more loaded than before. In addition, interconnection between remotely located power systems turned out to be a common practice. These give rise to low frequency oscillations in the range of 0.1-3.0 Hz. If not well damped, these oscillations may keep growing in magnitude until loss of synchronism results. Power system stabilizers (PSSs) have been used in the last few decades to serve the purpose of enhancing power system damping to low frequency oscillations. PSSs have proved to be efficient in performing their assigned tasks. The objective of this chapter is to investigate the potential of particle swarm optimization as a tool in designing UPFC-based stabilizers to improve power system transient stability. To estimate the controllability of each of the UPFC control signals on the electromechanical modes, singular value decomposition is employed. The problem of designing all the UPFCbased stabilizers individually is formulated as an optimization problem. Particle swarm optimizer is utilized to search for the optimum stabilizer parameter settings that optimize a given objective function. Coordinated design of the different stabilizers is also carried out by finding the best parameter settings for more than one stabilizer at a given operating condition in a coordinated manner

    Routinely transradial arterial approach for extra-cranial carotid stenting

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    BackgroundThe purpose of this study is to report a single center experience with its safety and feasibility of transradial arterial (TRA) approach in extra-cranial carotid artery (ECCA) stenting.Methods and results74 patients were consecutively enrolled in this study. A retrograde-engagement technique, involving looping 6-F Kimny guiding catheter, was utilized for ECCA angiographic study. For ECCA stenting, the 6-F Kimny guiding catheter was replaced with a 7-F Kimny guiding catheter and the procedure was performed as the follows. First, a 0.035-in. Teflon wire was carefully advanced into the common CA. Second, a PercuSurge GuardWire was inserted into the external CA, followed by distal balloon inflation for an anchoring support. Third, the 6-F guiding catheter was removed, followed by exchanging a 7-F kimny guiding catheter which was advanced along the 0.035-in. Teflon wire and the PercuSurge GuardWire to proximal part of common CA. Distal protection device was then utilized to protect from distal embolization during the procedure. One procedure failed due to external CA did not provide an anchoring support. Thus, the procedure was successful in 74 (98.7%) patients. No vascular or bleeding complication was observed. Minor stroke occurred in 3 (4.0%) patients during the procedure. All of them were completely recovery within 1week.ConclusionsThe TRA approach for ECCA stenting is safe and feasible. This access may offer a last resort for patients with unsuited to femoral arterial access and endarterectomy

    Control of tomato early blight and wilt using aqueous extract of neem leaves

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    The effect of neem (Azadiracta indica) leaf extract against Alternaria solani and Fusarium oxysporum, the causal agents of early blight and wilt of tomato plants (Lycopersicon esculentum Mill.) respectively, was studied. Concentrations (5, 10 and 20%) of aqueous neem extract suppressed mycelial growth of both pathogenic fungi and the degree of suppression gradually increased with increasing concentration. A concentration of 20% aqueous neem leaf extract sprayed on tomato plants lowered the incidence of Alternaria early blight from 53.2 to 42.5% after two weeks and from 100 to 79.2% after 4 weeks. Spraying plus irrigation with the same extract lowered the severity of Alternaria early blight from 26.8 to 11.4% after 2 weeks and from 61.7 to 17.9% after 4 weeks (control ratio of 43.71% after 4 weeks). For F. oxysporum wilt, germination of tomato seeds was highest in pots containing the negative control (soil free of pathogen) and in pots irrigated with the aqueous neem extract. The lowest disease incidence (19.04%) was obtained in pots treated with the pathogen and irrigated with aqueous neem extract, where an 81% control of Fusarium wilt was achieved. Growth parameters of tomato (shoot and root length, number of leaves, fresh and dry weight of shoots and roots) were studied 4, 6 and 8 weeks after sowing in the presence of the pathogens. There was a significant gradual increase in growth parameters when the plants were sprayed and irrigated with aqueous neem extract with the greatest improvement recorded 8 weeks after sowing

    Activated thrombin-activatable fibrinolysis inhibitor (TAFIa) attenuates breast cancer cell metastatic behaviors through inhibition of plasminogen activation and extracellular proteolysis

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    Thrombin activatable fibrinolysis inhibitor (TAFI) is a plasma zymogen, which can be converted to activated TAFI (TAFIa) through proteolytic cleavage by thrombin, plasmin, and most effectively thrombin in complex with the endothelial cofactor thrombomodulin (TM). TAFIa is a carboxypeptidase that cleaves carboxyl terminal lysine and arginine residues from protein and peptide substrates, including plasminogen-binding sites on cell surface receptors. Carboxyl terminal lysine residues play a pivotal role in enhancing cell surface plasminogen activation to plasmin. Plasmin has many critical functions including cleaving components of the extracellular matrix (ECM), which enhances invasion and migration of cancer cells. We therefore hypothesized that TAFIa could act to attenuate metastasis

    Entwicklung nachhaltiger Pflanzenschutzstrategien zur Bek_mpfung von Schadschmetterlingen im olivenanbau

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    Current olive growing practices range from the traditional Mediterranean olive grove to intensively managed olive plantations. Insecticides against major olive pests, like the olive moth (Prays oleae, Lep.: Yponomeutidae) and the jasmine moth, (Palpita unionalis, Lep.: Pyralidae) are still applied frequently. The European Union-funded international research project TRIPHELIO is aimed at the development of economically feasible and sustainable insecticide-free control methods for key Lepidopterous pests of olive. Main research activities focus on (1) the use of pheromones for mating disruption and improved monitoring of target pests, (2) habitat management strategies to enhance the activity of natural enemies in the olive grove, and (3) the use of inundative releases of mass-reared egg parasitoids of the genus Trichogramma. Moreover, tools for successful integration of the methods developed into an integrated pest management (IPM) strategy for olive pests were explored by optimising techniques for surveillance as well as considering potential side-effects of common pesticides on beneficial organisms. An intense exchange of scientific information and technology between European and North African countries was undertaken to create solutions for a wide range of olive growing regions. Key results and recommendations for further essential steps towards practical implementation are presented in this publication.Zusammenfassung Traditionelle, extensiv bearbeitete Olivenhaine, aber auch moderne Intensiv-Plantagen mit k_nstlicher Bew_sserung und hohem Einsatz von D_ngern bzw. chemischen Pflanzenschutzmitteln kennzeichnen die derzeitigen verschiedenen Anbauformen der Olive im Mittelmeerraum. Schadlepidopteren wie die Olivenmotte (Prays oleae, Lep.: Yponomeutidae) und die Jasminmotte (Palpita unionalis, Lep.: Pyralidae) werden durch regelm_ssigen Insektizideinsatz bek_mpft. Das von der EU gef_rderte internationale Forschungsprojekt TRIPHELIO zielte auf die Entwicklung insektizidfreier Alternativmethoden durch (1) die Optimierung der pheromongest _tzten _berwachung und Verwirrtechnik, (2) der Anwendung von Habitatmanagement-Strategien zur F_rderung nat_rlicher Gegenspieler, und (3) dem Einsatz von Trichogramma-Schlupfwespen. Zus_tzlich wurden Module f_r eine optimale Anwendung biotechnischer und biologischer Methoden bez_glich der Ph_nologie der Schadinsekten und m_glicher Nebenwirkungen von Pestiziden erarbeitet. Die intensive Kooperation zwischen Wissenschaftlern und Praktikern aus mehreren L_ndern Europas und Nordafrikas erlaubte den Entwurf m_glicher L_sungsans_tze f_r verschiedene Anbaubedingungen und klimatische Regionen des Mittelmeerraumes. Die wichtigsten Ergebnisse und Ausblicke f_r eine zuk_nftige praktische Umsetzung werden in dieser Ver_ffentlichung beschrieben

    Evaluation of Bond Strength of Aesthetic Type of Posts at Different Regions of Root Canal after Application of Adhesive Resin Cement

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    AIM: This study aimed to evaluate the bond strength between esthetic posts and dentin at different regions of the root canal in passive mode or push-out active mode. METHODS: Twenty extracted human bicuspid single canal teeth were used in this study. Teeth were sectioned below the cement-enamel junction. The roots of teeth were endodontically treated. Glass fibre posts (Glassix plus, Harald Nordin SA, Switzerland) and zirconia posts (Zirix, Harald Nordin) were then adhesively luted with total-etch (Variolink N, Ivoclar Vivadent, Schaan, Liechtenstein) and self-adhesive (Multilink Speed, Ivoclar Vivadent) resin cement. The roots were divided into two main groups of 10 samples each, according to the type of post used. Each group subdivided into 2 subgroups of 5 samples each, according to the type of cement used. The specimens were transversally sectioned into three slices of 2 mm thickness to perform the push-out test. The push-out tests were performed at crosshead-speed, 0.5 mm/min). Failure modes were evaluated using a scanning electron microscope at magnification (x 150). RESULTS: The results revealed that push-out bond strengths were significantly affected by the type of luting agent and the type of post (P ≤ 0 .05). The mean push-out bond strength values for fibre post were significantly higher than those for zirconia post independent of the luting strategy used. The score values of total-etch adhesive resin cement were higher than those for self-adhesive resin cement irrespective of other variables. Regarding the effect of the root segment on push-out bond strength, results revealed that bond strength decreased from the coronal to the apical section. The cement-dentin interface found to be the weakest part of the root-cement-post unit. CONCLUSION: Glass fibre posts revealed better results in all root third when they adhesively luted with total-etch or self-etch adhesive resin cement and provided significantly increased bond strength compared to the zirconia posts

    Effect of Intravenous Dexmedetomidine Infusion on Interleukin-6 (IL-6) and Plasma Cortisol in Open Heart Surgery

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    Aim of the work: to evaluate the effect of intravenous dexmedetomidine infusion on patients undergoing open heart surgery regarding stress response markers as plasma interleukin-6 and plasma cortisol. Patents and Methods: Fifty consecutive patients aged 18-70years, scheduled for elective open heart surgery using CPB technique were enrolled in this study at the Cardiothoracic Surgery Unit, Luxor international hospital, from July 2018 to May 2019. Patients randomly assigned using closed envelope technique into two equal groups according to the drug infused intraoperatively: 1st group (25 patients):- Dexmedetomidine group (Group D); received loading dose of intravenous dexmedetomidine infusion of 1 μg/kg IV dissolved in 20ml normal saline over 10 minutes followed by maintenance dose of 0.5 μg/kg/hr. till the end of surgery where 0.5 μg /kg/h was calculated for each patient and dissolved in 12.5 ml normal saline 2nd group ( 25 patients):- placebo group (Group P); receive 20ml intravenous infusion of normal saline 0.9 % over 10 minutes followed by continuous infusion of 12.5 ml of normal saline till the end of surgery. Results: Our study revealed that HR and MAP wasn’t significantly different between the two groups at the baseline, but significantly lowered in Dex. group after induction, during CPB, post CPB, and postoperative.Dexometomedine suppress the intraoperative and postoperative rise of IL-6 which was significantly higher in placebo group relative to Dex. group. Also dexometomedine has effect on stress hormone as serum cortisol and serum glucose decease in Dex. group relative to placebo group. None of studied cases revealed bradycardia or hypotention and there are no significant difference between groups regarding side effect drowsiness, nausea and vomiting Conclusion: This study demonstrated that the continuous administration of dexmedetomidine during open heart surgery with CPB suppressed intraoperative and post-operative cytokine secretion, and improved post-operative inflammatory response indices in the present study. Also it stabilize blood pressure and heart rate and blunt cardiovascular response to CPB. These results could be attributed to the anti-inflammatory effects of dexmedetomidine
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