16 resultados para Pontier, Aug.
Resumo:
At a time when the traditional major airlines have struggled to remain viable, the low-cost carriers have become the major success story of the European airline industry. This paper looks behind the headlines to show that although low-cost airlines have achieved much, they too have potential weaknesses and face a number of challenges in the years ahead. The secondary and regional airports that have benefited from low-cost carrier expansion are shown to be vulnerable to future changes in airline economics, government policy and patterns of air service. An analysis of routes from London demonstrates that the low-cost airlines have been more successful in some markets than others. To attractive and historically under-served leisure destinations in Southern Europe they have stimulated dramatic growth and achieved a dominant position. To major hub cities however they typically remain marginal players and to secondary points in Northern Europe their traffic has been largely diverted from existing operators. There is also evidence that the UK market is becoming saturated and new low-cost services are poaching traffic from other low-cost routes. Passenger compensation legislation and possible environmental taxes will hit the low-cost airline industry disproportionately hard. The high elasticities of demand to price in certain markets that these airlines have exploited will operate in reverse. One of the major elements of the low-cost business model involves the use of smaller uncongested airports. These offer faster turn-arounds and lower airport charges. In many cases, local and regional government has been willing to subsidise expansion of air services to assist with economic development or tourism objectives. However, recent court cases against Ryanair now threaten these financial arrangements. The paper also examines the catchment areas for airports with low-cost service. It is shown that as well as stimulating local demand, much traffic is captured from larger markets nearby through the differential in fare levels. This has implications for surface transport, as access to these regional airports often involves long journeys by private car. Consideration is then given to the feasibility of low-cost airlines expanding into the long-haul market or to regional operations with small aircraft. Many of the cost advantages are more muted on intercontinental services.
Resumo:
In this presentation I discuss two recent works that use new technologies to explore the expression or communication of individual human identity.
Resumo:
In proposing theories of how we should design and specify networks of processes it is necessary to show that the semantics of any language we use to write down the intended behaviours of a system has several qualities. First in that the meaning of what is written on the page reflects the intention of the designer; second that there are no unexpected behaviours that might arise in a specified system that are hidden from the unsuspecting specifier; and third that the intention for the design of the behaviour of a network of processes can be communicated clearly and intuitively to others. In order to achieve this we have developed a variant of CSP, called CSPt, designed to solve the problems of termination of parallel processes present in the original formulation of CSP. In CSPt we introduced three parallel operators, each with a different kind of termination semantics, which we call synchronous, asynchronous and race. These operators provide specifiers with an expressive and flexible tool kit to define the intended behaviour of a system in such a way that unexpected or unwanted behaviours are guaranteed not to take place. In this paper we extend out analysis of CSPt and introduce the notion of an alphabet diagram that illustrates the different categories of events that can arise in the parallel composition of processes. These alphabet diagrams are then used to analyse networks of three processes in parallel with the aim of identifying sufficient constraints to ensure associativity of their parallel composition. Having achieved this we then proceed to prove associativity laws for the three parallel operators of CSPt. Next, we illustrate how to design and construct a network of three processes that satisfy the associativity law, using the associativity theorem and alphabet diagrams. Finally, we outline how this could be achieved for more general networks of processes.
Resumo:
In proposing theories of how we should design and specify networks of processes it is necessary to show that the semantics of any language we use to write down the intended behaviours of a system has several qualities. First in that the meaning of what is written on the page reflects the intention of the designer; second that there are no unexpected behaviours that might arise in a specified system that are hidden from the unsuspecting specifier; and third that the intention for the design of the behaviour of a network of processes can be communicated clearly and intuitively to others. In order to achieve this we have developed a variant of CSP, called CSPt, designed to solve the problems of termination of parallel processes present in the original formulation of CSP. In CSPt we introduced three parallel operators, each with a different kind of termination semantics, which we call synchronous, asynchronous and race. These operators provide specifiers with an expressive and flexible tool kit to define the intended behaviour of a system in such a way that unexpected or unwanted behaviours are guaranteed not to take place. In this paper we extend out analysis of CSPt and introduce the notion of an alphabet diagram that illustrates the different categories of events that can arise in the parallel composition of processes. These alphabet diagrams are then used to analyse networks of three processes in parallel with the aim of identifying sufficient constraints to ensure associativity of their parallel composition. Having achieved this we then proceed to prove associativity laws for the three parallel operators of CSPt. Next, we illustrate how to design and construct a network of three processes that satisfy the associativity law, using the associativity theorem and alphabet diagrams. Finally, we outline how this could be achieved for more general networks of processes.
Resumo:
Region merging algorithms commonly produce results that are seen to be far below the current commonly accepted state-of-the-art image segmentation techniques. The main challenging problem is the selection of an appropriate and computationally efficient method to control resolution and region homogeneity. In this paper we present a region merging algorithm that includes a semi-greedy criterion and an adaptive threshold to control segmentation resolution. In addition we present a new relative performance indicator that compares algorithm performance across many metrics against the results from human segmentation. Qualitative (visual) comparison demonstrates that our method produces results that outperform existing leading techniques.
Resumo:
The aim of this study is to give an interpretation of the urban transformations connected to rail transit system investments; in particular the main research goal is to analyze and give a methodological support for the urban transformation phenomena government in the rail transit stations areas. The article proposes an empirical studies comparative analysis and an application in the Naples urban area, in which a new rail transit network has been developed. In particular the socio-economic transit impacts on the urban system are measured and interpretated with the support of a GIS; therefore an application of the node-place interpretative model (Bertolini 1999) is proposed in order to support transit–land use planning processes in the stations areas.
Resumo:
This paper reports on a Field Programmable Gate Array (FPGA) implementation as well as prototyping for real-time testing of a low complexity high efficiency decimation filter processor which is deployed in conjunction with a custom built low-power jitter insensitive Continuous Time (CT) Sigma-Delta (Σ-Δ) Modulator to measure and assess its performance. The CT Σ-Δ modulator/decimation filter cascade can be used in integrated all-digital microphone interfaces for a variety of applications including mobile phone handsets, wireless handsets as well as other applications requiring all-digital microphones. The work reported here concentrates on the design and implementation as well as prototyping on a Xilinx Spartan 3 FPGA development system and real-time testing of the decimation processing part deploying All-Pass based structures to process the bit stream coming from CT Σ-Δ modulator hence measuring in real-time and fully assessing the modulator's performance.