267 research outputs found
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Urban traffic management and Intelligent Transport Systems: A European perspective
The objective of this paper is to establish the state-of-the-art of urban traffic management in Europe, with a particular focus on Intelligent Transport Systems (ITS), using data collected from 34 cities directly with the help of a purpose-developed questionnaire. Several areas of traffic management are covered, such as: general statistics of the transport systems, organisational structures, monitoring and forecasting, provision of traffic information and urban traffic control. Special focus is also given to demand management, traffic control centres, public transport and parking. Broadly summarising the results, it can be said that a wide range of traffic management technologies and policies are used in Europe. It is encouraging to see that strategic plans and traffic control centres are generally present in the participating cities, as well as facilities for public transport, ITS technologies and real-time public transport information. In addition, most cities have cycling infrastructure, pedestrian zones and alternative mobility schemes, as well as good policies for weaker population categories, such as the elderly, the jobless and the disabled. While the study has some limitations with respect to the reliability of the data provided by the cities, mainly originating from different definitions or from the absence of data all together, it can be considered a fairly good overview of the state-of-the art of urban traffic management in Europe
p-wave phase shift and scattering length of Li
We have calculated the p-wave phase shifts and scattering length of Li.
For this we solve the partial wave Schr\"odinger equation and analyze the
validity of adopting the semiclassical solution to evaluate the constant
factors in the solution. Unlike in the wave case, the semiclassical
solution does not provide unique value of the constants. We suggest an
approximate analytic solution, which provides reliable results in special
cases. Further more, we also use the variable phase method to evaluate the
phase shifts. The p-wave scattering lengths of Cs and Cs are
calculated to validate the schemes followed. Based on our calculations, the
value of the wave scattering length of Li is .Comment: 10 figure
Influence of test methodology and probe geometry on nanoscale fatigue mechanisms of diamond-like carbon thin film
The aim of this paper is to investigate the mechanism of nanoscale fatigue using nano-impact and multiple-loading cycle nanoindentation tests, and compare it to previously reported findings of nanoscale fatigue using integrated stiffness and depth sensing approach. Two different film loading mechanisms, loading history and indenter shapes are compared to comprehend the influence of test methodology on the nanoscale fatigue failure mechanisms of a DLC film. An amorphous 100 nm thick DLC film was deposited on a 500 μm silicon substrate using sputtering of graphite target in pure argon atmosphere. Nano-impact and multiple-load cycle indentations were performed in the load range of 100 μN to 1000 μN and 0.1 mN to 100 mN, respectively. Both test types were conducted using conical and Berkovich indenters. Results indicate that for the case of a conical indenter, the combination of nano-impact and multiple-loading cycle nanoindentation tests provides information on the life and failure mechanism of the DLC film, which is comparable to the previously reported findings using the integrated stiffness and depth sensing approach. However, the comparison of results is sensitive to the applied load, loading mechanism, test-type and probe geometry. The loading mechanism and load history are therefore critical which also lead to two different definitions of film failure. The choice of exact test methodology, load and probe geometry should therefore be dictated by the in-service tribological conditions, and where necessary both test methodologies can be used to provide better insights of failure mechanism. Molecular dynamics (MD) simulations of the elastic response of nanoindentation are reported, which indicate that the elastic modulus of the film measured using MD simulation was higher than that experimentally measured. This difference is attributed to the factors related to the presence of material defects, crystal structure, residual stress, indenter geometry and loading/unloading rate differences between the MD and experimental results
Internet of Things and data mining: from applications to techniques and systems
The Internet of Things (IoT) is the result of the convergence of sensing, computing, and networking technologies, allowing devices of varying sizes and computational capabilities (things) to intercommunicate. This communication can be achieved locally enabling what is known as edge and fog computing, or through the well‐established Internet infrastructure, exploiting the computational resources in the cloud. The IoT paradigm enables a new breed of applications in various areas including health care, energy management and smart cities. This paper starts off with reviewing these applications and their potential benefits. Challenges facing the realization of such applications are then discussed. The sheer amount of data stemmed from devices forming the IoT requires new data mining systems and techniques that are discussed and categorized later in this paper. Finally, the paper is concluded with future research directions
The vulnerability of the petroleum supply chain
Oil and its products are the main fuel of today's global society. It is therefore necessary to ensure the continuous, smooth and uninterrupted flow of oil to end users. The aim of this thesis is to examine and assess the ability of the petroleum supply chain to retain functionality when damaged in some way. The main causes of interruptions considered are random failures, such as natural disasters or accidental damages, malicious attacks and intentional disruptions. The research seeks a holistic assessment of oil supply chain vulnerability addressing such interruptions. A literature review is conducted on the topographic properties of networks and how network structure is related to reliability, vulnerability, robustness and criticality. The disruption causes and the various measures of vulnerability are also examined in order to identify the characteristics of critical failure scenarios. Literature review is further extended over the development, operations and management of the oil supply chain and the response measures in place for replacing and recovering lost throughput in case of a disruption. The methodology adopted consists of three optimization stages, namely shortest path finding, flow assignment and network interdiction. Shortest path finding is concerned with the topographic features of the oil supply chain and more specifically with the establishment of optimal origin-destination paths. The oil supply chain that is modelled as a multi-origin multi-destination spatial network making use of Djikstra's shortest path search algorithm. The second optimization stage regards the assignment of flow and the satisfaction of user demand. A minimum cost flow problem similar to the transportation problem is used for that purpose. The model is fitted to the oil context by adding a fleet capacity constraint and a deterministic fleet velocity factor. The latter optimization stage is conducted using a game theoretic interdiction model based on a two-player zero-sum game mixed strategy proposed by Bell (2000). The results obtained are both of methodological and practical nature. Vulnerability has been assessed for two different set-ups of the oil supply network aiming to capture different vulnerability aspects. The results highlight vulnerable network components and stress weak locations where infrastructure improvements can be made. Furthermore, policy weaknesses are identified.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
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