692 research outputs found
CAD/FEA Tools and the Analysis of Design for Optimization
No full textA thesis presented to the faculty of the College of Science and Technology at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science by Patil Yogesh on October 21, 2006
Investigating consumer adoption, usage and impact of broadband: UK households
No full textThis thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Despite a large investment, the majority of countries especially the UK demonstrate a slow adoption of broadband. In order to enhance the adoption and use of broadband this research examines the factors influencing the decisions of household consumers. This research aims to address the two main areas of concern: first, to investigate consumer-level factors affecting the adoption of broadband in UK households; and second, to understand the usage of broadband and its impact upon household consumers in the UK. This research adopted a quantitative approach that was executed in the following steps. First, it developed a conceptual model by selecting and justifying relevant constructs from appropriate theories and models related to technology adoption, usage and impact. Second, it operationalised the constructs by developing and validating the research instrument by employing the content validity, reliability and construct validity approach. Finally, it empirically validated and refined the conceptual model by employing a survey research approach.
The findings suggested that all the constructs included in the conceptual model, except knowledge, significantly influence the consumers when adopting broadband in a UK household. The significant constructs include relative advantage, utilitarian outcomes, hedonic outcomes, primary influence, facilitating conditions resources and self-efficacy. The rate and variety of Internet usage is significantly higher for broadband consumers than narrowband ones. It was also found that significantly more numbers of broadband consumers perceived changes in time allocation patterns on various daily life activities than narrowband ones. This research contributes towards theory, practice and policy. The contribution of this research towards theory is that it integrates and determines the appropriate information systems (IS) literature in order to enhance knowledge of technology adoption from the consumers' perspectives. An added contribution to theory is the development and validation of a research instrument that future studies can utilise to examine broadband and other similar technologies in household context. Considering the slow adoption of broadband, this research also provides implications for policy makers and the providers of broadband in order to encourage and promote homogenous adoption and usage
Open Quantum Systems: Controlling System-Bath Interactions and Studying their Influence
No full textAll quantum systems are open to some extent, i.e. they interact with their environment. In this thesis, we develop novel techniques to control these system-bath interactions and then demonstrate through experiments their significant influence on system properties and dynamics. We develop a novel imaging technique in the context of ultracold lattice gases. This imaging technique allows us to tune the rate at which the atoms are measured (which can be thought of as an interaction with the electromagnetic radiation environment) over several orders of magnitude, without concomitant heating or loss of the atoms. Using this technical ability, we show that in the weak measurement limit, the atoms undergo unabated quantum evolution, i.e. they freely tunnel around the lattice, whereas as the measurement strength is increased, the tunnelling gets suppressed, the coherence is lost, and the atoms approach a classical limit of slower diffusion; demonstrating the influence of the degree of system-bath interactions on the system's dynamics. Moreover, the dissipation of open systems also allows for the realization of driven-dissipative phase transitions. We demonstrate and characterize such a phase transition in a system of ultrahigh-Q optomechanical Silicon Nitride membrane resonators, and then employ it to study the influence of system-bath interactions on criticality and phase transitions. In particular, we develop an active feedback protocol that allows us to change not only the strength of the resonators' interactions with the bath but also the very nature of their interactions (non-Markovian vs Markovian). We experimentally demonstrate that these can markedly influence the criticality of the driven-dissipative phase transition through measurements of critical and scaling exponents, which significantly change with changing system-bath interactions. Furthermore, we also demonstrate that the very phases that the system supports can be influenced by the interactions – a class of non-Markovian interactions is shown to effect a phase, a nonequilibrium steady state, that has no analog in the Markovian case. Lastly, we consider a couple of applications of these resonator systems to enhance force-sensing capabilities. We also discuss the future prospects of such control techniques and other extensions of the works presented in this thesis for gaining further insights into the influence of system-bath interactions on system properties and behavior. [1] Nondestructive imaging of an ultracold lattice gas, Y. S. Patil, S. Chakram, L. M. Aycock, and M. Vengalattore, Physical Review A, 90, 033422 (2014) [2] Measurement-induced localization of an ultracold lattice gas, Y. S. Patil, S. Chakram, and M. Vengalattore, Physical Review Letters 115, 140402 (2015) [3] Thermomechanical Two-Mode Squeezing in an Ultrahigh-Q Membrane Resonator, Y. S. Patil, S. Chakram, L. Chang, and M. Vengalattore, Physical Review Letters 115, 017202 (2015) [4] Critical behavior of a driven dissipative system: Universality beyond the Markovian regime, Y. S. Patil, H. F. H. Cheung, T. Villazon, A. G. Date, A. Polkovnikov, A. Chandran, and M. Vengalattore [5] Emergent dynamical order and time translation symmetry breaking due to non-Markovian system-bath interactions, Y. S. Patil, H. F. H. Cheung, and M. Vengalattore [6] Back-action evading measurements of two quadratures using a parametric coupling, Y. S. Patil, S. Chakram, and M. Vengalattore [7] Multimode phononic correlations in a nondegenerate parametric amplifier, S. Chakram, Y. S. Patil, and M. Vengalattore, New Journal of Physics 17, 063018 (2015) [8] Emergent phases and novel critical behavior in a non-Markovian open quantum system, H. F. H. Cheung, Y. S. Patil, and M. Vengalattore, Physical Review A (2018) [9] Demonstration of enhanced force sensitivity using a transient squeezing protocol, H. F. H. Cheung, Y. S. Patil, L. Chang, S. Chakram, and M. Vengalattore [10] Dissipation in ultrahigh quality factor SiN membrane resonators, S. Chakram, Y. S. Patil, L. Chang, and M. Vengalattore, Physical Review Letters 112, 127201 (2014
Preference prediction through feature-based collaborative filtering of textual reviews
No full textText reviews are often used by users to decide whether to buy a product or watch a movie or dine in a restaurant. Most of these reviews are raw text and lack a formal structure. Computers cannot easily understand and interpret these reviews to analyze and aggregate them. Users have to manually read through these reviews to find the useful information about the concerned restaurant. We use the topical and sentimental information compiled from raw textual reviews to understand user preferences. We use these preferences to cluster similar users together and then predict users' topical feelings towards the restaurants for which they may be requesting information and to make suitable recommendations. Users have similarities in their preferences for particular topics under which the restaurants have been reviewed. Therefore, we can soft-cluster them using these similarities extracted from their reviewing history. These cluster membership probabilities help us make predictions about the user's sentiments in each topic for the target restaurant. Our results show our accuracy for predicting these sentiments and show that we can provide recommendations to users in most topics for the target restaurant.M.S.Includes bibliographical referencesIncludes vitaby Yogesh Kakodka
Learning API mappings for programming platforms
No full textSoftware developers often need to port applications written for a source platform to a target platform. One of the key tasks here is to find matching API calls in the target platform for the given API calls in the source platform. This task involves exhaustive reading in target platform API (Application Programming Interface) documentation to identify API methods corresponding to the given API methods of the source platform. We introduce an approach to the problem of inferring mapping between the APIs of a source and target platforms. It is constructed based on independently developed applications on source and target platforms performing similar functionality. We observe that in building these applications, developers exercised knowledge of the corresponding APIs. We develop two dynamic analysis techniques to systematically harvest this knowledge and infer likely mappings between the Graphical APIs of JavaME and Android Graphical platform. Rosetta Mapper: A tool which provides a ranked list of target API methods or method sequences that likely map to each source API method or method sequences. Rosetta Classifier: A supervised learning tool which classifies whether the given mapping between source API and target API is true or false using support vector machines.M.S.Includes bibliographical referencesby Yogesh Padmanaba
Copolymerization of Ethylene with 1-Hexene Catalyzed by Titanium Complexes Bearing Carbamates Ligands
No full text
Innovative catalysts based on niobium and tantalum carbamates for olefins polymerization
No full textAn Innovative Trifluoromethyl Radical from Persistent Radical as Efficient Initiator for the Radical Copolymerization of Vinylidene Fluoride with tert-butyl α-Trifluoromethacrylate
No full textInternational audienceA persistent perfluoroalkyl radical (PPFR), perfluoro-3-ethyl-2,4-dimethyl-3-pentyl, was shown to be a good source of *CF3 radicals able to initiate the radical copolymerization of vinylidene fluoride (VDF) with tert-butyl α-trifluoromethacrylate (MAF-TBE). Three copolymerizations of VDF with MAF-TBE were performed at 90 °C and at different concentrations of PPFR to examine the effect on molecular weights, end groups, degrees of polymerization, yields, chains defects and degradation temperatures of the resulting copolymers (Table 1). NMR characterizations of the resulting poly(VDF-co-MAF-TBE) copolymers showed that copolymerization was exclusively initiated by *CF3 radicals, as evidenced from the thermal decomposition of PPFR at T > 80 °C. The addition of *CF3 radical onto VDF/MAF-TBE system was regioselective leading to CF3-CH2-CF2* radical that further cross propogated onto MAF-TBE unit and the α,-trifluoromethyl groups acted as an efficient label to assess the molecular weights of the resulting copolymers by 19F NMR spectroscopy. Three [PPFR]0/([VDF]0+[MAF-TBE]0)initial molar ratios (0.5, 1.0 and 2.0 %) led to various molecular weights ranging from 10,000 to 20,000 g.mol-1. When that ratio decreased, both the molecular weights and the thermostability of these original poly(VDF-co-MAF-TBE) copolymers increase. reference P. Yogesh, T. Ono and B. Ameduri submitted to ACS Macro Letters (in press
An Innovative Trifluoromethyl Radical from Persistent Radical as Efficient Initiator for the Radical Copolymerization of Vinylidene Fluoride with tert-butyl α-Trifluoromethacrylate
No full textInternational audienceA persistent perfluoroalkyl radical (PPFR), perfluoro-3-ethyl-2,4-dimethyl-3-pentyl, was shown to be a good source of *CF3 radicals able to initiate the radical copolymerization of vinylidene fluoride (VDF) with tert-butyl α-trifluoromethacrylate (MAF-TBE). Three copolymerizations of VDF with MAF-TBE were performed at 90 °C and at different concentrations of PPFR to examine the effect on molecular weights, end groups, degrees of polymerization, yields, chains defects and degradation temperatures of the resulting copolymers (Table 1). NMR characterizations of the resulting poly(VDF-co-MAF-TBE) copolymers showed that copolymerization was exclusively initiated by *CF3 radicals, as evidenced from the thermal decomposition of PPFR at T > 80 °C. The addition of *CF3 radical onto VDF/MAF-TBE system was regioselective leading to CF3-CH2-CF2* radical that further cross propogated onto MAF-TBE unit and the α,-trifluoromethyl groups acted as an efficient label to assess the molecular weights of the resulting copolymers by 19F NMR spectroscopy. Three [PPFR]0/([VDF]0+[MAF-TBE]0)initial molar ratios (0.5, 1.0 and 2.0 %) led to various molecular weights ranging from 10,000 to 20,000 g.mol-1. When that ratio decreased, both the molecular weights and the thermostability of these original poly(VDF-co-MAF-TBE) copolymers increase. reference P. Yogesh, T. Ono and B. Ameduri submitted to ACS Macro Letters (in press
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