Stability of periodic solutions obtained via the averaging method for nonsmooth Lipschitz system

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Economic impact of alternative policy measures implemented on the energy activities of the Catalan production system: an input-output analysis

The aim of the paper is to analyse the economic impact of alternative policies implemented on the energy activities of the Catalan production system. Specifically, we analyse the effects of a tax on intermediate energy uses, a reduction in the final production of energy, and a reduction in intermediate energy uses. The methodology involves two versions of the input-output price model: a competitive price formulation and a mark-up price formulation. The input-output price framework will make it possible to evaluate how the alternative measures modify production prices, consumption prices, private welfare, and intermediate energy uses. The empirical application is for the Catalan economy and uses economic data for the year 2001.

Numerical simulation of combined heat transfer phenomena (conduction, convection, and radiation). Application to he optimisation of thermal systems

Thermal systems interchanging heat and mass by conduction, convection, radiation (solar and thermal ) occur in many engineering applications like energy storage by solar collectors, window glazing in buildings, refrigeration of plastic moulds, air handling units etc. Often these thermal systems are composed of various elements for example a building with wall, windows, rooms, etc. It would be of particular interest to have a modular thermal system which is formed by connecting different modules for the elements, flexibility to use and change models for individual elements, add or remove elements without changing the entire code. A numerical approach to handle the heat transfer and fluid flow in such systems helps in saving the full scale experiment time, cost and also aids optimisation of parameters of the system. In subsequent sections are presented a short summary of the work done until now on the orientation of the thesis in the field of numerical methods for heat transfer and fluid flow applications, the work in process and the future work.

The identity type weak factorisation system

We show that the classifying category C(T)of a dependent type theory T with axioms for identity types admits a nontrivial weak factorisation system. After characterising this weak factorisation system explicitly, we relate it to the homotopy theory of groupoids.

System analysis of a Peer-to-Peer Video-on-Demand architecture: Kangaroo

Architectural design and deployment of Peer-to-Peer Video-on-Demand (P2PVoD) systems which support VCR functionalities is attracting the interest of an increasing number of research groups within the scientific community; especially due to the intrinsic characteristics of such systems and the benefits that peers could provide at reducing the server load. This work focuses on the performance analysis of a P2P-VoD system considering user behaviors obtained from real traces together with other synthetic user patterns. The experiments performed show that it is feasible to achieve a performance close to the best possible. Future work will consider monitoring the physical characteristics of the network in order to improve the design of different aspects of a VoD system.

Model based fault diagnosis with application to an automotive engine

Report for the scientific sojourn at the University of Linköping between April to July 2007. Monitoring of the air intake system of an automotive engine is important to meet emission related legislative diagnosis requirements. During the research the problem of fault detection in the air intake system was stated as a constraint satisfaction problem over continuous domains with a big number of variables and constraints. This problem was solved using Interval-based Consistency Techniques. Interval-based consistency techniques are shown to be particularly efficient for checking the consistency of the Analytical Redundancy Relations (ARRs), dealing with uncertain measurements and parameters, and using experimental data. All experiments were performed on a four-cylinder turbo-charged spark-ignited SAAB engine located in the research laboratory at Vehicular System Group - University of Linköping.

The clinical application of converting enzyme inhibitors.

Chronic blockade of the renin angiotensin system became possible when orally active inhibitors of angiotensin converting enzyme, the enzyme which catalyzes the transformation of angiotensin I into angiotensin II, were synthetized. Two compounds, captopril and enalapril, have been investigated in clinical studies. The decrease of the pressor response to exogenous angiotensin I and of the circulating levels of angiotensin II following administration of these inhibitors has been demonstrated to be directly related to the degree of suppression of plasma angiotensin converting enzyme activity. These inhibitors have been shown to normalize blood pressure alone in some hypertensive patients whereas in many others, satisfactory blood pressure control can be achieved only after the addition of a diuretic. Captopril and enalapril also markedly improve cardiac function of patients with chronic congestive heart failure. Chronic blockade of the renin angiotensin system has therefore provided an interesting new approach to the treatment of clinical hypertension and heart failure.

Towards an emotion-driven interactive music system: ridging the gaps between affect, physiology and sound generation

Report for the scientific sojourn at the Stanford University from January until June 2007. Music is well known for affecting human emotional states, yet the relationship between specific musical parameters and emotional responses is still not clear. With the advent of new human-computer interaction (HCI) technologies, it is now possible to derive emotion-related information from physiological data and use it as an input to interactive music systems. Providing such implicit musical HCI will be highly relevant for a number of applications including music therapy, diagnosis, nteractive gaming, and physiologically-based musical instruments. A key question in such physiology-based compositions is how sound synthesis parameters can be mapped to emotional states of valence and arousal. We used both verbal and heart rate responses to evaluate the affective power of five musical parameters. Our results show that a significant correlation exists between heart rate and the subjective evaluation of well-defined musical parameters. Brightness and loudness showed to be arousing parameters on subjective scale while harmonicity and even partial attenuation factor resulted in heart rate changes typically associated to valence. This demonstrates that a rational approach to designing emotion-driven music systems for our public installations and music therapy applications is possible.

A Soft Edge Target Zone Model: Theory And Application To Hong Kong

Hong Kong’s currency is pegged to the US dollar in a currency board arrangement. In autumn 2003, the Hong Kong dollar appreciated from close to 7.80 per US dollar to 7.70, as investors feared that the currency board would be abandoned. In the wake of this appreciation, the monetary authorities revamped the one-sided currency board mechanism into a symmetric two-sided system with a narrow exchange rate band. This paper reviews the characteristics of the new currency board arrangement and embeds a theoretical soft edge target zone model typifying many intermediate regimes, to explain the notable achievement of speculative peace and credibility since May 2005.

Off-the-Record Target Zones: Theory with an Application to Hong Kongs Currency Board

This paper provides a modelling framework for evaluating the exchange rate dynamics of a target zone regime with undisclosed bands. We generalize the literature to allow for asymmetric one-sided regimes. Market participants' beliefs concerning an undisclosed band change as they learn more about central bank intervention policy. We apply the model to Hong Kong's one-sided currency board mechanism. In autumn 2003, the Hong Kong dollar appreciated from close to 7.80 per US dollar to 7.70, as investors feared that the currency board would be abandoned. In the wake of this appreciation, the monetary authorities finally revamped the regime as a symmetric two-sided system with a narrow exchange rate band.

Spanish pension system: population aging and immigration policy

There is a widespread consensus in the literature that, as consequence of the demographic transition, the current Spanish pension system will become unsustainable in the next decades. In this article we evaluate the sustainability of the contributory pensions' sub-system, taking into account the demographic projections by the Spanish Statistical Office (INE). A baseline scenario is projected as well as several reforms are simulated, focusing on: (i) selective immigration policy, (ii) changes in the way of setting the pensions and (iii) increase of the legal age of retirement up to 68. The main results are the following. The current system would not incur deficits until 2018, from then deficits will begin to be accumulated. The expenditure in pensions practically would double (from 8.3 % in 2005 to 17.2 % in 2050). A selective immigration policy -towards foreign young people- would help, but does not solve the long-term sustainability of the current system. A policy that combines a pensions' growth at a pace lower than productivity growth and extends the legal age of retirement up to 68 would give solvency to the system beyond 2029

System GMM estimation with a small sample

Properties of GMM estimators for panel data, which have become very popular in the empirical economic growth literature, are not well known when the number of individuals is small. This paper analyses through Monte Carlo simulations the properties of various GMM and other estimators when the number of individuals is the one typically available in country growth studies. It is found that, provided that some persistency is present in the series, the system GMM estimator has a lower bias and higher efficiency than all the other estimators analysed, including the standard first-differences GMM estimator.

Plasmacytoid dendritic cells: one-trick ponies or workhorses of the immune system?

Plasmacytoid dendritic cells (pDCs) were first described as interferon-producing cells and, for many years, their overlapping characteristics with both lymphocytes and classical dendritic cells (cDCs) created confusion over their exact ontogeny. In this Viewpoint article, Nature Reviews Immunology asks five leaders in the field to discuss their thoughts on the development and functions of pDCs--do these cells serve mainly as a major source of type I interferons or do they also make other important contributions to immune responses?

Discontinuous Galerkin methods for the one-dimensional Vlasov-Poisson system

We construct a new family of semi-discrete numerical schemes for the approximation of the one-dimensional periodic Vlasov-Poisson system. The methods are based on the coupling of discontinuous Galerkin approximation to the Vlasov equation and several finite element (conforming, non-conforming and mixed) approximations for the Poisson problem. We show optimal error estimates for the all proposed methods in the case of smooth compactly supported initial data. The issue of energy conservation is also analyzed for some of the methods.

A general multiserver state-dependent queueing system

The work studies a general multiserver queue in which the service time of an arriving customer and the next interarrival period may depend on both the current waiting time and the server assigned to the arriving customer. Stability of the system is proved under general assumptions on the predetermined distributions describing the model. The proof exploits a combination of the Markov property of the workload process with a regenerative property of the process. The key idea leading to stability is a characterization of the limit behavior of the forward renewal process generated by regenerations. Extensions of the basic model are also studied.