172 research outputs found

    A seven-level cascaded multilevel inverter based on simplified SVPWM method

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    The multilevel converters are extremely widespread alternatives within megawatt power level as well as medium voltage level applications due to their excellent execution than the typical two-level converters. The widely applied control strategies aimed at inverters are Sine Pulse Width Modulation (SPWM) and Space Vector Pulse Width Modulation (SVPWM) strategies. In between these two PWM methods, the SVPWM strategy has excellent execution as compared to the SPWM strategy as a result of improved DC link voltage use as well as a decrease in Total Harmonic Distortion (THD) in output voltages. A traditional SVPWM strategy owns numerous weaknesses like computational complications in terms of identification of the reference voltage vector position, to identify sector, triangle and also it requires large memory for storing look up tables used for switching vectors. This paper presents, an innovative modified SVPWM strategy aimed at Cascaded H-Bridge Multilevel Inverter (CHBMLI). The novel modified SVPWM strategy has overwhelm the downsides of traditional SVPWM strategy. A seven-level CHBMLI is used for the implementation of this simplified SVPWM method to assess performance and as well to made comparison with the SPWM strategy. A MATLAB software is used for the simulation

    5-level torque-hysteresis controller for DTC based IM drive

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    In the recent trade demand, the AC machines and drives are extensively utilized. Normally, the AC drives exploit with high efficacy as well as high performance. Among other things, one of the best control strategies is Direct torque control (DTC). For this article, the induction motor drive is projected very simple amended DTC scheme in accordance with the hysteresis controller. By the reason of its modest assembly & effective execution, DTC is used for AC as well as DC drive as associated to other monitoring structures. The presence of high ripple content in output torque for DTC scheme is only an obstacle. This article approaches extenuation of the ripples in torque by varying the predictable 5-level torque hysteresis controller used in DTC. The expansion of distinctive switching approach has been generated for chosen voltage vector. On the basis of ripple content simulation outcomes fulfilled in MATLAB/SIMULINK for hysteresis torque controller to minimized the ripples

    Electroforming free high resistance resistive switching of graphene oxide modified polar-PVDF

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    Future nanoelectronics for nonvolatile memory elements require novel materials and devices that can switch logic states with a low power consumption, minimum heat dissipation, high-circuit density, fast switching speed, large endurance and long charge retention period. Herein, we report novel high resistance resistive switching in a polar beta-polyvinylidene fluoride (beta-PVDF) and graphene oxide (GO) composite. A high resistance switching ratio was achieved without the realization of the essential current-filament forming condition mainly responsible for switching the device from high to low resistance states. beta-PVDF is a well known ferroelectric/piezoelectric material which changes shape and size after application of an external electric field. We propose a model which describes how the present beta-PVDF-GO composite changes shape after application of an external electric field (E) which provides a favorable environment for the formation of the current linkage path of GO in the PVDF matrix. The applied positive SET electric fields (+E) switch the composite from a high to a low resistance state, which further re-switches from a low to a high resistance state under negative RE-SET electric fields (-E). The positive and negative E-fields are responsible for the contraction and expansion of beta-PVDF, respectively, redox reactions between GO and adsorbed water, oxygen migrations, and/or metal diffusion from the electrode to the beta-PVDF-GO matrix. The above mentioned characteristics of the composite allows switching from one high resistance state to another high resistance state. The switching current lies below the range of 10-100 mu A with an exceptionally high switching ratio, which meets one of the prerequisite criteria of low power nanoelectronics memristors

    Reaching the unreached: An initiative to bridge the gap between the gap by active role of management institutes/schools

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    There are large numbers of business communities in India which neither had any formal education nor they took any professional training but still they contribute in successful business formation. Their presence can be felt in all areas of business. Still there is a big professional gap between the educational institutes, specially the B-Schools and this independent business community. With the help of this paper an effort is made to develop a Two-Way learning relationship for the mutual benefit of both entities. It will also highlight the role of an educational institute beyond academics for the well being of society. This may lead to derive and develop the exchange of innovative business ideas and framing the suitable policies for long term sustainability in today´s competitive arena. The study conducted by researcher with a sample size of 100 which includes a mix of well known academic professionals, MBA students and non academic business professionals has revealed that there is a need of an exchange program for the mutual benefits. There exists a big professional gap in this area which can be filled with the active and effective initiative by management institutes. An effort is made in this paper to highlight this gap and to suggest some framework to bridge the ga

    Detecting Malicious Applications from the cloud by using user feedback method

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    As in recent period of computers and internets, mobiles devices, Smartphone’s plays a vital role in human day to day activities. Also now a days Smartphone’s & tablets are becoming very popular especially android based Smartphone’s are gaining much more popularity as compared to Apple’s iOS. These Smartphone’s having lot of applications and features based on only internet but these new emerging features of these devices give opportunity to new malwares & threats. Android is comparatively new OS hence its makes very hard to detect and prevent these viruses and malwares attacks by using some basic traditional mechanisms. So security of these Smartphone’s is now becoming very popular issue of researchers. The lack of standard security mechanism in Android applications is very useful to hackers. So to overcome these various pitfalls we use cloud services as a security weapon for providing decent security system for Android applications

    BMSQABSE: Design of a Bioinspired Model to Improve Security & QoS Performance for Blockchain-Powered Attribute-based Searchable Encryption Applications

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    Attribute-based searchable encryption (ABSE) is a sub-field of security models that allow intensive searching capabilities for cloud-based shared storage applications. ABSE Models require higher computational power, which limits their application to high-performance computing devices. Moreover, ABSE uses linear secret sharing scheme (LSSS), which requires larger storage when compared with traditional encryption models. To reduce computational complexity, and optimize storage cost, various researchers have proposed use of Machine Learning Models (MLMs), that assist in identification & removal of storage & computational redundancies. But most of these models use static reconfiguration, thus cannot be applied to large-scale deployments. To overcome this limitation, a novel combination of Grey Wolf Optimization (GWO) with Particle Swarm Optimization (PSO) model to improve Security & QoS performance for Blockchain-powered Attribute-based Searchable Encryption deployments is proposed in this text. The proposed model augments ABSE parameters to reduce its complexity and improve QoS performance under different real-time user request scenarios. It intelligently selects cyclic source groups with prime order & generator values to create bilinear maps that are used for ABSE operations. The PSO Model assists in generation of initial cyclic population, and verifies its security levels, QoS levels, and deployment costs under multiple real-time cloud scenarios. Based on this initial analysis, the GWO Model continuously tunes ABSE parameters in order to achieve better QoS & security performance levels via stochastic operations. The proposed BMSQABSE model was tested under different cloud configurations, and its performance was evaluated for healthcare deployments. Based on this evaluation, it was observed that the proposed model achieved 8.3% lower delay, with 4.9% lower energy consumption, 14.5% lower storage requirements when compared with standard ABSE models. It was able to mitigate Distributed Denial of Service (DDoS), Masquerading, Finney, and Sybil attacks, which assists in deploying the proposed model for QoS-aware highly secure deployments

    Association of umbilical cord blood lead with neonatal behavior at varying levels of exposure

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    BACKGROUND: In the light of the ongoing debate about lowering the cut-off for acceptable blood lead level to <5 ÎĽg/dL from the currently recommended level of <10 ÎĽg/dL, we considered whether prenatal exposure to varying levels of lead is associated with similar or disparate effects on neonatal behavior. METHODS: Using Brazelton's Neonatal Behavioral Assessment Scale (NBAS), an epidemiological approach and robust statistical techniques like multivariate linear regression, logistic regression, Poisson regression and structural equations modeling analyses we estimated the simultaneous indirect effects of umbilical cord blood lead (CBL) levels and other neonatal covariates on the NBAS clusters. RESULTS: We observed that when analyzed in all study subjects, the CBL levels independently and strongly influenced autonomic stability and abnormal reflexes clusters. However, when the analysis was restricted to neonates with CBL <10 ÎĽg/dL, CBL levels strongly influenced the range of state, motor and autonomic stability clusters. Abnormal walking reflex was consistently associated with an increased CBL level irrespective of the cut-off for CBL, however, only at the lower cut-offs were the predominantly behavioral effects of CBL discernible. CONCLUSION: Our results further endorse the need to be cognizant of the detrimental effects of blood lead on neonates even at a low-dose prenatal exposure

    Reactive Extraction of Citric Acid Using Different Extractants: Equilibrium, Kinetics and Modeling

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    Recovery of citric acid from biotechnologically produced low concentration aqueous solution has attracted several separation techniques for the downstream processing. Amongst them, reactive extraction is a convenient, cheap, and effective method. Three different extractants are used in this study, namely tri-n-butyl phosphate (TBP), tri-n-octylamine (TOA), and Aliquat 336 (A336), all diluted in methyl-iso-butyl ketone (MIBK). The isothermal batch experiments were performed for the equilibrium and kinetic studies at T = 300.15±1 K. Around 92 % extraction efficiency (E %) was obtained using 20 % (v/v) TOA in MIBK. Based on the overloading of amine (Z > 0.5), (2:1) acid:extractant complex in TOA+MIBK phase was proposed. Kinetics of extraction of citric acid (0.2–0.8 kmol m–3) was also performed in a Lewis-type stirred cell, using TOA in MIBK. The extraction reaction was occurring in the diffusion film. The second order rate constant was calculated as k2 = 0.0351 m3 kmol–1 s–1. The extraction parameters were estimated by differential evolution optimization technique. Optimal value of equilibrium constant, KE, was found to be 3.6 · 10–3 (m3 kmol–1)2, for the reactive extraction of citric acid using 20 % TOA in MIBK, and was found in close agreement with experimental values. This work is licensed under a Creative Commons Attribution 4.0 International License

    A simple method to combine multiple molecular biomarkers for dichotomous diagnostic classification

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    BACKGROUND: In spite of the recognized diagnostic potential of biomarkers, the quest for squelching noise and wringing in information from a given set of biomarkers continues. Here, we suggest a statistical algorithm that – assuming each molecular biomarker to be a diagnostic test – enriches the diagnostic performance of an optimized set of independent biomarkers employing established statistical techniques. We validated the proposed algorithm using several simulation datasets in addition to four publicly available real datasets that compared i) subjects having cancer with those without; ii) subjects with two different cancers; iii) subjects with two different types of one cancer; and iv) subjects with same cancer resulting in differential time to metastasis. RESULTS: Our algorithm comprises of three steps: estimating the area under the receiver operating characteristic curve for each biomarker, identifying a subset of biomarkers using linear regression and combining the chosen biomarkers using linear discriminant function analysis. Combining these established statistical methods that are available in most statistical packages, we observed that the diagnostic accuracy of our approach was 100%, 99.94%, 96.67% and 93.92% for the real datasets used in the study. These estimates were comparable to or better than the ones previously reported using alternative methods. In a synthetic dataset, we also observed that all the biomarkers chosen by our algorithm were indeed truly differentially expressed. CONCLUSION: The proposed algorithm can be used for accurate diagnosis in the setting of dichotomous classification of disease states

    Effect of nutrition, harvesting date and fruit canopy position on yield and quality of Kinnow mandarin (Citrus nobilis x Citrus deliciosa)

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    Attractive peel colour and quality development in Kinnow (Citrus nobilis Lour x Citrus deliciosa Tenara) is a prime requisite for its fair market price. The objective of study was to find out the impact of canopy position, date of harvesting and nutrition on yield and quality of Kinnow mandarin. A field experiment was conducted in a four year old Kinnow orchard using factorial randomized block design with three replications. There were nine treatments comprised of various N, P, K levels and one control; two canopy positions (external and internal) and three harvesting dates (06.12.13, 26.12.13 and 16.01.14). Statistical analysis using SAS 9.3 software and Tukey's HSD test revealed the significance of various treatments, canopy positions and harvesting dates (P<0.01).The treatment comprising 400g+600g+240g (N+P2O5+K2O/plant) was found the best among other treatments with respect to yield (20.06 kg/tree) and other quality parameters (TSS, acidity, ascorbic acid and total carotenoids). Fruits which are present on external canopy of tree were superior in terms of quality (TSS, ascorbic acid, total carotenoids) as compared to fruits present on internal canopy of the tree.The Kinnow fruits harvested during the last week of December were found superior in terms of total carotenoids in juice and peel and ascorbic acid content. While the fruits harvested in second week of January were found superior in terms of TSS and acidity. Application of 400g, 600g and 240g of NPK respectively was found beneficial for quality fruit production of Kinnow. Quality of Kinnow fruits vary as per canopy position and date of harvesting, hence they should harvest at different times and also from different canopy positions according to purpose
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