894 resultados para Superlinear and Semi–Superlinear Convergence
Resumo:
An ambitious rendering of the digital future from a pioneer of media and cultural studies, a wise and witty take on a changing field, and our orientation to it Investigates the uses of multimedia by creative and productive citizen-consumers to provide new theories of communication that accommodate social media, participatory action, and user-creativity Leads the way for new interdisciplinary engagement with systems thinking, complexity and evolutionary sciences, and the convergence of cultural and economic values Analyzes the historical uses of multimedia from print, through broadcasting to the internet Combines conceptual innovation with historical erudition to present a high-level synthesis of ideas and detailed analysis of emergent forms and practices Features an international focus and global reach to provide a basis for students and researchers seeking broader perspectives
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Cloud computing is a currently developing revolution in information technology that is disturbing the way that individuals and corporate entities operate while enabling new distributed services that have not existed before. At the foundation of cloud computing is the broader concept of converged infrastructure and shared services. Security is often said to be a major concern of users considering migration to cloud computing. This article examines some of these security concerns and surveys recent research efforts in cryptography to provide new technical mechanisms suitable for the new scenarios of cloud computing. We consider techniques such as homomorphic encryption, searchable encryption, proofs of storage, and proofs of location. These techniques allow cloud computing users to benefit from cloud server processing capabilities while keeping their data encrypted; and to check independently the integrity and location of their data. Overall we are interested in how users may be able to maintain and verify their own security without having to rely on the trust of the cloud provider.
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As a key element in their response to new media forcing transformations in mass media and media use, newspapers have deployed various strategies to not only establish online and mobile products, and develop healthy business plans, but to set out to be dominant portals. Their response to change was the subject of an early investigation by one of the present authors (Keshvani 2000). That was part of a set of short studies inquiring into what impact new software applications and digital convergence might have on journalism practice (Tickle and Keshvani 2000), and also looking for demonstrations of the way that innovations, technologies and protocols then under development might produce a “wireless, streamlined electronic news production process (Tickle and Keshvani 2001).” The newspaper study compared the online products of The Age in Melbourne and the Straits Times in Singapore. It provided an audit of the Singapore and Australia Information and Communications Technology (ICT) climate concentrating on the state of development of carrier networks, as a determining factor in the potential strength of the two services with their respective markets. In the outcome, contrary to initial expectations, the early cable roll-out and extensive ‘wiring’ of the city in Singapore had not produced a level of uptake of Internet services as strong as that achieved in Melbourne by more ad hoc and varied strategies. By interpretation, while news websites and online content were at an early stage of development everywhere, and much the same as one another, no determining structural imbalance existed to separate these leading media participants in Australia and South-east Asia. The present research revisits that situation, by again studying the online editions of the two large newspapers in the original study, and one other, The Courier Mail, (recognising the diversification of types of product in this field, by including it as a representative of Newscorp, now a major participant). The inquiry works through the principle of comparison. It is an exercise in qualitative, empirical research that establishes a comparison between the situation in 2000 as described in the earlier work, and the situation in 2014, after a decade of intense development in digital technology affecting the media industries. It is in that sense a follow-up study on the earlier work, although this time giving emphasis to content and style of the actual products as experienced by their users. It compares the online and print editions of each of these three newspapers; then the three mastheads as print and online entities, among themselves; and finally it compares one against the other two, as representing a South-east Asian model and Australian models. This exercise is accompanied by a review of literature on the developments in ICT affecting media production and media organisations, to establish the changed context. The new study of the online editions is conducted as a systematic appraisal of the first level, or principal screens, of the three publications, over the course of six days (10-15.2.14 inclusive). For this, categories for analysis were made, through conducting a preliminary examination of the products over three days in the week before. That process identified significant elements of media production, such as: variegated sourcing of materials; randomness in the presentation of items; differential production values among media platforms considered, whether text, video or stills images; the occasional repurposing and repackaging of top news stories of the day and the presence of standard news values – once again drawn out of the trial ‘bundle’ of journalistic items. Reduced in this way the online artefacts become comparable with the companion print editions from the same days. The categories devised and then used in the appraisal of the online products have been adapted to print, to give the closest match of sets of variables. This device, to study the two sets of publications on like standards -- essentially production values and news values—has enabled the comparisons to be made. This comparing of the online and print editions of each of the three publications was set up as up the first step in the investigation. In recognition of the nature of the artefacts, as ones that carry very diverse information by subject and level of depth, and involve heavy creative investment in the formulation and presentation of the information; the assessment also includes an open section for interpreting and commenting on main points of comparison. This takes the form of a field for text, for the insertion of notes, in the table employed for summarising the features of each product, for each day. When the sets of comparisons as outlined above are noted, the process then becomes interpretative, guided by the notion of change. In the context of changing media technology and publication processes, what substantive alterations have taken place, in the overall effort of news organisations in the print and online fields since 2001; and in their print and online products separately? Have they diverged or continued along similar lines? The remaining task is to begin to make inferences from that. Will the examination of findings enforce the proposition that a review of the earlier study, and a forensic review of new models, does provide evidence of the character and content of change --especially change in journalistic products and practice? Will it permit an authoritative description on of the essentials of such change in products and practice? Will it permit generalisation, and provide a reliable base for discussion of the implications of change, and future prospects? Preliminary observations suggest a more dynamic and diversified product has been developed in Singapore, well themed, obviously sustained by public commitment and habituation to diversified online and mobile media services. The Australian products suggest a concentrated corporate and journalistic effort and deployment of resources, with a strong market focus, but less settled and ordered, and showing signs of limitations imposed by the delay in establishing a uniform, large broadband network. The scope of the study is limited. It is intended to test, and take advantage of the original study as evidentiary material from the early days of newspaper companies’ experimentation with online formats. Both are small studies. The key opportunity for discovery lies in the ‘time capsule’ factor; the availability of well-gathered and processed information on major newspaper company production, at the threshold of a transformational decade of change in their industry. The comparison stands to identify key changes. It should also be useful as a reference for further inquiries of the same kind that might be made, and for monitoring of the situation in regard to newspaper portals on line, into the future.
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Three new procedures - in the context of estimation of virial coefficients and summation of the partial virial series for hard discs and hard spheres - are proposed. They are based on the parametrised Euler transformation, a novel resummation, identity and the ε-convergence methods respectively. A comparison with other estimates (molecular dynamics, graph theory and empirical methods) reveals satisfactory agreement.
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Austria and Finland are persistently referred to as the “success stories” of post-1945 European history. Notwithstanding their different points of departure, in the course of the Cold War both countries portrayed themselves as small and neutral border-states in the world dictated by superpower politics. By the 1970s, both countries frequently ranked at the top end in various international classifications regarding economic development and well-being in society. This trend continues today. The study takes under scrutiny the concept of consensus which figures centrally in the two national narratives of post-1945 success. Given that the two domestic contexts as such only share few direct links with one another and are more obviously different than similar in terms of their geographical location, historical experiences and politico-cultural traditions, the analogies and variations in the anatomies of the post-1945 “cultures of consensus” provide an interesting topic for a historical comparative and cross-national examination. The main research question concerns the identification and analysis of the conceptual and procedural convergence points of the concepts of the state and consensus. The thesis is divided into six main chapters. After the introduction, the second chapter presents the theoretical framework in more detail by focusing on the key concepts of the study – the state and consensus. Chapter two also introduces the comparative historical and cross-national research angles. Chapter three grounds the key concepts of the state and consensus in the historical contexts of Austria and Finland by discussing the state, the nation and democracy in a longer term comparative perspective. The fourth and fifth chapter present case studies on the two policy fields, the “pillars”, upon which the post-1945 Austrian and Finnish cultures of consensus are argued to have rested. Chapter four deals with neo-corporatist features in the economic policy making and chapter five discusses the building up of domestic consensus regarding the key concepts of neutrality policies in the 1950s and 1960s. The study concludes that it was not consensus as such but the strikingly intense preoccupation with the theme of domestic consensus that cross-cut, in a curiously analogous manner, the policy-making processes studied. The main challenge for the post-1945 architects of Austrian and Finnish cultures of consensus was to find strategies and concepts for consensus-building which would be compatible with the principles of democracy. Discussed at the level of procedures, the most important finding of the study concerns the triangular mechanism of coordination, consultation and cooperation that set into motion and facilitated a new type of search for consensus in both post-war societies. In this triangle, the agency of the state was central, though in varying ways. The new conceptions concerning a small state’s position in the Cold War world also prompted cross-nationally perceivable willingness to reconsider inherited concepts and procedures of the state and the nation. At the same time, the ways of understanding the role of the state and its relation to society remained profoundly different in Austria and Finland and this basic difference was in many ways reflected in the concepts and procedures deployed in the search for consensus and management of domestic conflicts. For more detailed information, please consult the author.
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Photonic crystals (PhCs) influence the propagation of light by their periodic variation in dielectric contrast or refractive index. This review outlines the attractive optical qualities inherent to most PhCs namely the presence of full or partial photonic band gaps and the possibilities they present towards the inhibition of spontaneous emission and the localization of light. Colloidal self-assembly of polymer or silica spheres is one of the most favoured and low cost methods for the formation of PhCs as artificial opals. The state of the art in growth methods currently used for colloidal self-assembly are discussed and the use of these structures for the formation of inverse opal architectures is then presented. Inverse opal structures with their porous and interconnected architecture span several technological arenas - optics and optoelectronics, energy storage, communications, sensor and biological applications. This review presents several of these applications and an accessible overview of the physics of photonic crystal optics that may be useful for opal and inverse opal researchers in general, with a particular emphasis on the recent use of these three-dimensional porous structures in electrochemical energy storage technology. Progress towards all-optical integrated circuits may lie with the concepts of the photonic crystal, but the unique optical and structural properties of these materials and the convergence of PhC and energy storage disciplines may facilitate further developments and non-destructive optical analysis capabilities for (electro)chemical processes that occur within a wide variety of materials in energy storage research.
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It is increasingly evident that evolutionary processes play a role in how ecological communities are assembled. However the extend to which evolution influences how plants respond to spatial and environmental gradients and interact with each other is less clear. In this dissertation I leverage evolutionary tools and thinking to understand how space and environment affect community composition and patterns of gene flow in a unique system of Atlantic rainforest and restinga (sandy coastal plains) habitats in Southeastern Brazil.
In chapter one I investigate how space and environment affect the population genetic structure and gene flow of Aechmea nudicaulis, a bromeliad species that co-occurs in forest and restinga habitats. I genotyped seven microsatellite loci and sequenced one chloroplast DNA region for individuals collected in 7 pairs of forest / restinga sites. Bayesian genetic clustering analyses show that populations of A. nudicaulis are geographically structured in northern and southern populations, a pattern consistent with broader scale phylogeographic dynamics of the Atlantic rainforest. On the other hand, explicit migration models based on the coalescent estimate that inter-habitat gene flow is less common than gene flow between populations in the same habitat type, despite their geographic discontinuity. I conclude that there is evidence for repeated colonization of the restingas from forest populations even though the steep environmental gradient between habitats is a stronger barrier to gene flow than geographic distance.
In chapter two I use data on 2800 individual plants finely mapped in a restinga plot and on first-year survival of 500 seedlings to understand the roles of phylogeny, functional traits and abiotic conditions in the spatial structuring of that community. I demonstrate that phylogeny is a poor predictor of functional traits in and that convergence in these traits is pervasive. In general, the community is not phylogenetically structured, with at best 14% of the plots deviating significantly from the null model. The functional traits SLA, leaf dry matter content (LDMC), and maximum height also showed no clear pattern of spatial structuring. On the other hand, leaf area is strongly overdispersed across all spatial scales. Although leaf area overdispersion would be generally taken as evidence of competition, I argue that interpretation is probably misleading. Finally, I show that seedling survival is dramatically increased when they grow shaded by an adult individual, suggesting that seedlings are being facilitated. Phylogenetic distance to their adult neighbor has no influence on rates of survival though. Taken together, these results indicate that phylogeny has very limited influence on the fine scale assembly of restinga communities.
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It has long been recognised that dispersal abilities and environmental factors are important in shaping invertebrate communities, but their relative importance for primary soil community assembly has not yet been disentangled. By studying soil communities along chronosequences on four recently emerged nunataks (ice-free land in glacial areas) in Iceland, we replicated environmental conditions spatially at various geographical distances. This allowed us to determine the underlying factors of primary community assembly with the help of metacommunity theories that predict different levels of dispersal constraints and effects of the local environment. Comparing community assembly of the nunataks with that of non-isolated deglaciated areas indicated that isolation of a few kilometres did not affect the colonisation of the soil invertebrates. When accounting for effects of geographical distances, soil age and plant richness explained a significant part of the variance observed in the distribution of the oribatid mites and collembola communities, respectively. Furthermore, null model analyses revealed less co-occurrence than expected by chance and also convergence in the body size ratio of co-occurring oribatids, which is consistent with species sorting. Geographical distances influenced species composition, indicating that the community is also assembled by dispersal, e.g. mass effect. When all the results are linked together, they demonstrate that local environmental factors are important in structuring the soil community assembly, but are accompanied with effects of dispersal that may "override" the visible effect of the local environment.
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This paper investigates camera control for capturing bottle cap target images in the fault-detection system of an industrial production line. The main purpose is to identify the targeted bottle caps accurately in real time from the images. This is achieved by combining iterative learning control and Kalman filtering to reduce the effect of various disturbances introduced into the detection system. A mathematical model, together with a physical simulation platform is established based on the actual production requirements, and the convergence properties of the model are analyzed. It is shown that the proposed method enables accurate real-time control of the camera, and further, the gain range of the learning rule is also obtained. The numerical simulation and experimental results confirm that the proposed method can not only reduce the effect of repeatable disturbances but also non-repeatable ones.
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Cappadocian Greek is reported to display agglutinative inflection in its nominal system, namely, mono-exponential formatives for the marking of case and number, and NOM.SG-looking forms as the morphemic units to which inflection applies. Previous scholarship has interpreted these developments as indicating a shift in morphological type from fusion to agglutination, brought about by contact with Turkish. This study takes issue with these conclusions. By casting a wider net over the inflectional system of the language, it shows that, of the two types of agglutinative formations identified, only one evidences a radical departure from the inherited structural properties of Cappadocian noun inflection. The other, on the contrary, represents a typologically more conservative innovation. The study presents evidence that a combination of system-internal and -external motivations triggered the development of both types, it describes the mechanisms through which the innovation was implemented, and discusses the factors that favoured change.
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Assembly job shop scheduling problem (AJSP) is one of the most complicated combinatorial optimization problem that involves simultaneously scheduling the processing and assembly operations of complex structured products. The problem becomes even more complicated if a combination of two or more optimization criteria is considered. This thesis addresses an assembly job shop scheduling problem with multiple objectives. The objectives considered are to simultaneously minimizing makespan and total tardiness. In this thesis, two approaches viz., weighted approach and Pareto approach are used for solving the problem. However, it is quite difficult to achieve an optimal solution to this problem with traditional optimization approaches owing to the high computational complexity. Two metaheuristic techniques namely, genetic algorithm and tabu search are investigated in this thesis for solving the multiobjective assembly job shop scheduling problems. Three algorithms based on the two metaheuristic techniques for weighted approach and Pareto approach are proposed for the multi-objective assembly job shop scheduling problem (MOAJSP). A new pairing mechanism is developed for crossover operation in genetic algorithm which leads to improved solutions and faster convergence. The performances of the proposed algorithms are evaluated through a set of test problems and the results are reported. The results reveal that the proposed algorithms based on weighted approach are feasible and effective for solving MOAJSP instances according to the weight assigned to each objective criterion and the proposed algorithms based on Pareto approach are capable of producing a number of good Pareto optimal scheduling plans for MOAJSP instances.
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The neutron and proton single-particle spectral functions in asymmetric nuclear matter fulfill energy-weighted sum rules. The validity of these sum rules within the self-consistent Green's function approach is investigated. The various contributions to these sum rules and their convergence as a function of energy provide information about correlations induced by the realistic interaction between the nucleons. The study of the sum rules in asymmetric nuclear matter exhibits the isospin dependence of the nucleon-nucleon correlations.
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The relative stability of aggregate labor's share constitutes one of the great macroeconomic ratios. However, relative stability at the aggregate level masks the unbalanced nature of industry labor's shares – the Kuznets stylized facts underlie those of Kaldor. We present a two-sector – one labor-only and the other using both capital and labor – model of unbalanced economic development with induced innovation that can rationalize these phenomena as well as several other empirical regularities of actual economies. Specifically, the model features (i) one sector ("goods" production) becoming increasingly capital-intensive over time; (ii) an increasing relative price and share in total output of the labor-only sector ("services"); and (iii) diverging sectoral labor's shares despite (iii) an aggregate labor's share that converges from above to a value between 0 and unity. Furthermore, the model (iv) supports either a neoclassical steadystate or long-run endogenous growth, giving it the potential to account for a wide range of real world development experiences.
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Aim. To describe preliminary findings of how the profile of the use of blur, disparity and proximal cues varies between non-strabismic groups and those with different types of esotropia. Design. Case control study Methodology. A remote haploscopic photorefractor measured simultaneous convergence and accommodation to a range of targets containing all combinations of binocular disparity, blur and proximal (looming) cues. 13 constant esotropes, 16 fully accommodative esotropes, and 8 convergence excess esotropes were compared with age and refractive error matched controls, and 27 young adult emmetropic controls. All wore full refractive correction if not emmetropic. Response AC/A and CA/C ratios were also assessed. Results. Cue use differed between the groups. Even esotropes with constant suppression and no binocular vision (BV) responded to disparity in cues. The constant esotropes with weak BV showed trends for more stable responses and better vergence and accommodation than those without any BV. The accommodative esotropes made less use of disparity cues to drive accommodation (p=0.04) and more use of blur to drive vergence (p=0.008) than controls. All esotropic groups failed to show the strong bias for better responses to disparity cues found in the controls, with convergence excess esotropes favoring blur cues. AC/A and CA/C ratios existed in an inverse relationship in the different groups. Accommodative lag of >1.0D at 33cm was common (46%) in the pooled esotropia groups compared with 11% in typical children (p=0.05). Conclusion. Esotropic children use near cues differently from matched non-esotropic children in ways characteristic to their deviations. Relatively higher weighting for blur cues was found in accommodative esotropia compared to matched controls.
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We consider the numerical treatment of second kind integral equations on the real line of the form ∅(s) = ∫_(-∞)^(+∞)▒〖κ(s-t)z(t)ϕ(t)dt,s=R〗 (abbreviated ϕ= ψ+K_z ϕ) in which K ϵ L_1 (R), z ϵ L_∞ (R) and ψ ϵ BC(R), the space of bounded continuous functions on R, are assumed known and ϕ ϵ BC(R) is to be determined. We first derive sharp error estimates for the finite section approximation (reducing the range of integration to [-A, A]) via bounds on (1-K_z )^(-1)as an operator on spaces of weighted continuous functions. Numerical solution by a simple discrete collocation method on a uniform grid on R is then analysed: in the case when z is compactly supported this leads to a coefficient matrix which allows a rapid matrix-vector multiply via the FFT. To utilise this possibility we propose a modified two-grid iteration, a feature of which is that the coarse grid matrix is approximated by a banded matrix, and analyse convergence and computational cost. In cases where z is not compactly supported a combined finite section and two-grid algorithm can be applied and we extend the analysis to this case. As an application we consider acoustic scattering in the half-plane with a Robin or impedance boundary condition which we formulate as a boundary integral equation of the class studied. Our final result is that if z (related to the boundary impedance in the application) takes values in an appropriate compact subset Q of the complex plane, then the difference between ϕ(s)and its finite section approximation computed numerically using the iterative scheme proposed is ≤C_1 [kh log〖(1⁄kh)+(1-Θ)^((-1)⁄2) (kA)^((-1)⁄2) 〗 ] in the interval [-ΘA,ΘA](Θ<1) for kh sufficiently small, where k is the wavenumber and h the grid spacing. Moreover this numerical approximation can be computed in ≤C_2 N logN operations, where N = 2A/h is the number of degrees of freedom. The values of the constants C1 and C2 depend only on the set Q and not on the wavenumber k or the support of z.