Large shocks vs. small shocks. (Or does size matter? May be so.)

What are the shocks that drive economic fluctuations? The answer to this question requires as a first step solving the shock identification issue. This paper proposes a new identification scheme based on two aspects: the long-run effect of the shock (permanent or transitory), and the size of the shock (Large or small). This is done by using a threshold integrated moving average model (TIMA) previously introduced in the literature by the authors. Based on this model we develop a testing strategy to determine whether Large and small shocks have different long-run effects, as well as whether one of them is purely transitory. The paper analyzes the impulse response function of both types of shocks, and provides the asymptotic results sufficient to implement the above testing strategy. Based on these results we develop a new nonlinear permanent–transitory decomposition, that is applied to US stock prices to analyze the quality ofthe stock market, and to US GNP to investigate the asymmetric behavior of its shocks.Publicad

The role of new technologies in the economic growth of Andalucia

This paper explores the contribution of Information and Communication Technologies (ICT) on economic growth and labor productivity growth of Andalucía during 1995-2004. We find that the contribution of ICT assets to total market GVA growth is quantitatively modest. Anyway the contribution to GVA growth and employment growth within the intensive ICT sectors has experienced a considerable increase in Andalucía. Although our analysis detects that intensive ICT sectors exhibit a high productivity level with respect to that of the non intensive ones, our main conclusion is that the advantages that might emerge from the use of ICT are nor yet observable in the economic dynamics of Andalucía, at least in a similar manner to that of the most developed.Information and Communication Technologies, productivity growth, regional growth

Efficient memory management in VOD disk array servers usingPer-Storage-Device buffering

We present a buffering technique that reduces video-on-demand server memory requirements in more than one order of magnitude. This technique, Per-Storage-Device Buffering (PSDB), is based on the allocation of a fixed number of buffers per storage device, as opposed to existing solutions based on per-stream buffering allocation. The combination of this technique with disk array servers is studied in detail, as well as the influence of Variable Bit Streams. We also present an interleaved data placement strategy, Constant Time Length Declustering, that results in optimal performance in the service of VBR streams. PSDB is evaluated by extensive simulation of a disk array server model that incorporates a simulation based admission test.This research was supported in part by the National R&D Program of Spain, Project Number TIC97-0438.Publicad

Changes in hydrodynamic, structural and geochemical properties in carbonate rock samples due to reactive transport

Reactive transport plays an important role in the development of a wide range of both anthropic and natural processes affecting geological media. To predict the consequences of reactive transport processes on structural and hydrodynamic properties of a porous media at large time and spatial scales, numerical modeling is a powerful tool. Nevertheless, such models, to be realistic, need geochemical, structural and hydrodynamic data inputs representative of the studied reservoir or material. Here, we present an experimental study coupling traditional laboratory measurements and percolation experiments in order to obtain the parameters that define rock heterogeneity, which can be altered during the percolation of a reactive fluid. In order to validate the experimental methodology and identify the role of the initial heterogeneities on the localization of the reactive transport processes, we used three different limestones with different petrophysical characteristics. We tracked the changes of geochemical, structural and hydrodynamic parameters in these samples induced by the percolation of an acid fluid by measuring, before and after the percolation experiment, petrophysical and hydrodynamic properties of the rocks.Peer ReviewedPostprint (published version

Implementation of a Hardware/Software Platform for Real-Timedata-Intensive Applications in Hazardous Environments

Real-Time Technology and Applications Symposium. Brookline, MA, USA, 10-12 Oct. 1996In real-time data-intensive applications, the simultaneous achievement of the required performance and determinism is a difficult issue to address, mainly due to the time needed to perform I/O operations, which is more significant than the CPU processing time. Additional features need to be considered if these applications are intended to perform in hostile environments. In this paper, we address the implementation of a hardware/software platform designed to acquire, transfer, process and store massive amounts of information at sustained rates of several MBytes/sec, capable of supporting real-time applications with stringent throughput requirements under hazardous environmental conditions. A real-world system devoted to the inspection of nuclear power plants is presented as an illustrative examplePublicad

A comprehensive approach in performance evaluation for modernreal-time operating systems

In real-time computing the accurate characterization of the performance and determinism that a particular real-time operating system/hardware combination can provide for real-time applications is essential. This issue is not properly addressed by existing performance metrics mainly due to the lack of completeness and generalization. In this paper we present a set of comprehensive, easy-to-implement and useful metrics covering three basic real-time operating system features: response to external events, intertask synchronization and resource sharing, and intertask data transferring. The evaluation of real-time operating systems using a set of fine-grained metrics is fundamental to guarantee that we can reach the required determinism in real-world applications.Publicad

INDICATORS OF URBAN SUSTAINABILITY IN MEXICO

The principal objective of this project is to summarize the characteristics that define urban sustainability in Mexican cities; its basic principles and the advantages of their application in the development of future cities, as well as the description of the indicators of urban sustainability that directly affect the development of communities, from households, colonies or neighbourhoods to cities or regions. The project’s method is based on the analysis of bibliographical information and the revision of some practical cases that refer to the development of sustainable indicators in urban environment.Indicators, sustainability, urbanism, development, cities.

A Discussion of Thin Client Technology for Computer Labs

Computer literacy is not negotiable for any professional in an increasingly computerised environment. Educational institutions should be equipped to provide this new basic training for modern life. Accordingly, computer labs are an essential medium for education in almost any field. Computer labs are one of the most popular IT infrastructures for technical training in primary and secondary schools, universities and other educational institutions all over the world. Unfortunately, a computer lab is expensive, in terms of both initial purchase and annual maintenance costs, and especially when we want to run the latest software. Hence, research efforts addressing computer lab efficiency, performance or cost reduction would have a worldwide repercussion. In response to this concern, this paper presents a survey on thin client technology for computer labs in educational environments. Besides setting out the advantages and drawbacks of this technology, we aim to refute false prejudices against thin clients, identifying a set of educational scenarios where thin clients are a better choice and others requiring traditional solutions