972 resultados para Systems and Information Theory
Resumo:
Sociomateriality has been attracting growing attention in the Organization Studies and Information Systems literatures since 2007, with more than 140 journal articles now referring to the concept. Over 80 percent of these articles have been published since January 2011 and almost all cite the work of Orlikowski (2007, 2010; Orlikowski and Scott 2008) as the source of the concept. Only a few, however, address all of the notions that Orlikowski suggests are entailed in sociomateriality, namely materiality, inseparability, relationality, performativity, and practices, with many employing the concept quite selectively. The contribution of sociomateriality to these literatures is, therefore, still unclear. Drawing on evidence from an ongoing study of the adoption of a computer-based clinical information system in a hospital critical care unit, this paper explores whether the notions, individually and collectively, offer a distinctive and coherent account of the relationship between the social and the material that may be useful in Information Systems research. It is argued that if sociomateriality is to be more than simply a label for research employing a number of loosely related existing theoretical approaches, then studies employing the concept need to pay greater attention to the notions entailed in it and to differences in their interpretation.
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In this paper, we survey some recent results on stabilization and disturbance attenuation for nonlinear systems using a dissipativity approach. After reviewing the basic dissipativity concept, we stress the connections between Lyapunov designs and the problem of achieving passivity by feedback. Focusing on physical models, we then illustrate how the design of stabilizing feedback can take advantage of the natural energy balance equation of the system. Here stabilization is viewed as the task of shaping the energy of the system to enforce a minimum at the desired equilibrium. Finally, we show the implications of dissipativity theory as an appropriate framework to study the nonlinear H∞ control problem. © 2002 EUCA.
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Tedd, L.(2006). Program: a record of the first 40 years of electronic library and information systems. Program: electronic library and information systems,40(1), 11-26.
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Hurricanes are destructive storms with strong winds, intense storm surges, and heavy rainfall. The resulting impact from a hurricane can include structural damage to buildings and infrastructure, flooding, and ultimately loss of human life. This paper seeks to identify the impact of Hurricane Ivan on the aected population of Grenada, one of the Caribbean islands. Hurricane Ivan made landfall on 7th September 2004 and resulted in 80% of the population being adversely aected. The methods that were used to model these impacts involved performing hazard and risk assessments using GIS and remote sensing techniques. Spatial analyses were used to create a hazard and a risk map. Hazards were identied initially as those caused by storm surges, severe winds speeds, and flooding events related to Hurricane Ivan. These estimated hazards were then used to create a risk map. An innovative approach was adopted, including the use of hillshading to assess the damage caused by high wind speeds. This paper explains in detail the methodology used and the results produced.
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This paper provides algorithms that use an information-theoretic analysis to learn Bayesian network structures from data. Based on our three-phase learning framework, we develop efficient algorithms that can effectively learn Bayesian networks, requiring only polynomial numbers of conditional independence (CI) tests in typical cases. We provide precise conditions that specify when these algorithms are guaranteed to be correct as well as empirical evidence (from real world applications and simulation tests) that demonstrates that these systems work efficiently and reliably in practice.
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Urban mobility is one of the main challenges facing urban areas due to the growing population and to traffic congestion, resulting in environmental pressures. The pathway to urban sustainable mobility involves strengthening of intermodal mobility. The integrated use of different transport modes is getting more and more important and intermodality has been mentioned as a way for public transport compete with private cars. The aim of the current dissertation is to define a set of strategies to improve urban mobility in Lisbon and by consequence reduce the environmental impacts of transports. In order to do that several intermodal practices over Europe were analysed and the transport systems of Brussels and Lisbon were studied and compared, giving special attention to intermodal systems. In the case study was gathered data from both cities in the field, by using and observing the different transport modes, and two surveys were done to the cities users. As concluded by the study, Brussels and Lisbon present significant differences. In Brussels the measures to promote intermodality are evident, while in Lisbon a lot still needs to be done. It also made clear the necessity for improvements in Lisbon’s public transports to a more intermodal passenger transport system, through integration of different transport modes and better information and ticketing system. Some of the points requiring developments are: interchanges’ waiting areas; integration of bicycle in public transport; information about correspondences with other transport modes; real-time information to passengers pre-trip and on-trip, especially in buses and trams. After the identification of the best practices in Brussels and the weaknesses in Lisbon the possibility of applying some of the practices in Brussels to Lisbon was evaluated. Brussels demonstrated to be a good example of intermodality and for that reason some of the recommendations to improve intermodal mobility in Lisbon can follow the practices in place in Brussels.
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El contexto teórico y empírico de esta investigación sobre entonación, se enmarca dentro de la filosofía lingüística de la teoría sistémico-funcional. El modelo metodológico empleado se basa en la Lingüística de Corpus. La descripción de la adquisición y aprendizaje de la lengua extranjera está justificada dentro del marco teórico de la teoría de interlengua y la adquisición de segundas lenguas y lenguas extranjeras.. El presente estudio del corpus comparativo y longitudinal de aprendices y hablantes nativos de lengua inglesa, tiene como objetivo principal investigar los modelos de entonación producidos por ambos grupos de hablantes. Se pretende demostrar que la diferencia a nivel entonativo entre estos dos grupos no sólo tiene como resultado que los no nativos tengan acento extranjero; sino que puede afectar al mensaje transmitido, en cuanto a la estructura y organización de la información dentro del discurso oral en las metafunciones textual e interpersonal.. Se asume la existencia de un sistema entonativo de interlengua, de esta forma este análisis tiene como objeto no sólo reflejar los errores sino también los posibles sistemas aproximativos de los aprendices mencionados..
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In this paper, we present view-dependent information theory quality measures for pixel sampling and scene discretization in flatland. The measures are based on a definition for the mutual information of a line, and have a purely geometrical basis. Several algorithms exploiting them are presented and compare well with an existing one based on depth differences
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In this paper a look is taken at how the use of implant technology can be used to either increase the range of the abilities of a human and/or diminish the effects of a neural illness, such as Parkinson's Disease. The key element is the need for a clear interface linking the human brain directly with a computer. The area of interest here is the use of implant technology, particularly where a connection is made between technology and the human brain and/or nervous system. Pilot tests and experimentation are invariably carried out apriori to investigate the eventual possibilities before human subjects are themselves involved. Some of the more pertinent animal studies are discussed here. The paper goes on to describe human experimentation, in particular that carried out by the author himself, which led to him receiving a neural implant which linked his nervous system bi-directionally with the internet. With this in place neural signals were transmitted to various technological devices to directly control them. In particular, feedback to the brain was obtained from the fingertips of a robot hand and ultrasonic (extra) sensory input. A view is taken as to the prospects for the future, both in the near term as a therapeutic device and in the long term as a form of enhancement.
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The three decades of on-going executives’ concerns of how to achieve successful alignment between business and information technology shows the complexity of such a vital process. Most of the challenges of alignment are related to knowledge and organisational change and several researchers have introduced a number of mechanisms to address some of these challenges. However, these mechanisms pay less attention to multi-level effects, which results in a limited un-derstanding of alignment across levels. Therefore, we reviewed these challenges from a multi-level learning perspective and found that business and IT alignment is related to the balance of exploitation and exploration strategies with the intellec-tual content of individual, group and organisational levels.
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Information costs play a key role in determining the relative efficiency of alternative organisational structures. The choice of locations at which information is stored in a firm is an important determinant of its information costs. A specific example of information use is modelled in order to explore what factors determine whether information should be stored centrally or locally and if it should be replicated at different sites. This provides insights into why firms are structured hierarchically, with some decisions and tasks being performed centrally and others at different levels of decentralisation. The effects of new information technologies are also discussed. These can radically alter the patterns and levels of information costs within a firm and so can cause substantial changes in organisational structure.