Spin Chains with Non-Diagonal Boundaries and Trigonometric SOS Model with Reflecting End

In this paper we consider two a priori very different problems: construction of the eigenstates of the spin chains with non parallel boundary magnetic fields and computation of the partition function for the trigonometric solid-on-solid (SOS) model with one reflecting end and domain wall boundary conditions. We show that these two problems are related through a gauge transformation (so-called vertex-face transformation) and can be solved using the same dynamical reflection algebras.Comment: based on a talk given at RAQIS'10, Recent Advances in Quantum Integrable Systems, Annecy-le-Vieux, France, 15-18 June 201

Restructuring and economic performance: the experience of the Tunisian economy

This paper aims at identifying the sources of comparative advantage and the bottlenecksof the Tunisian economy. By using an activity analysis model and yearly data on theinput-output structure and the factor endowments, the paper determines the evolution ofthe potential of the Tunisian economy between 1983 and 1996 and some of its keyaspects that the industrial restructuring program of 1996 could improve or reinforce. Theanalysis sheds light on the scarcity of various types of labor, in particular of qualifiedlabor.economics of technology ;

Economic Restructuring and Total Factor Productivity Growth: Tunisia Over the Period 1983-2001

In this paper we aim to measure and decompose the growth of frontier total factor productivity (TFP) in Tunisia over the period 1983-2001. We define frontier TFP growth as the shift of the economy’s production frontier, which we obtain by solving for each year a linear program, a sort of aggregate DEA analysis. We then decompose this aggregate frontier TFP growth into changes in technology, terms of trade, efficiency and resource utilization. We can also attribute frontier TFP growth to its main beneficiaries: labor, decomposed into five types, capital, decomposed into two types, and the allowable trade deficit. We find that frontier TFP grew by about 1% a year after the introduction of the structural adjustment program of 1987. Labor, in particular unskilled labor, was the main beneficiary of frontier TFP growth. The Solow residual reflecting technological change was the main driver of frontier TFP growth. The terms of trade were not favorable to Tunisia. After 1992, while the Tunisian efficiency frontier moved outwards, the country moved away from its efficiency frontier. Cet article mesure et décompose la croissance de la productivité totale des facteurs (PTF) potentielle en Tunisie sur la période 1983 à 2001. La croissance de la PTF potentielle est définie comme le déplacement de la frontière d’efficience de l’économie, qui est déterminée chaque année à partir d’un programme de programmation linéaire, un genre d’analyse DEA macroéconomique. Cette croissance de la PFT potentielle est décomposée de deux façons : une fois en termes de sources de la croissance, à savoir le changement technologique, les variations de taux de change, les changements d’efficience et utilisation des ressources ; et une fois en termes de bénéficiaires de cette croissance, à savoir le travail, décomposé en cinq types, le capital, décomposé en deux types, et le déficit permis de la balance commerciale. Nous trouvons que la PTF potentielle a cru de 1 % par an après l’introduction du programme d’ajustement structurel de 1987. La croissance de la PTF potentielle est surtout due au résidu de Solow, qui capte le progrès technologique, et a surtout bénéficié au travail non-qualifié. Les termes de l’échange ne furent pas favorables à la Tunisie. Après 1992, la frontière d’efficience s’est déplacée vers l’extérieur, mais la Tunisie s’est distancée de sa frontière d’efficience.Total factor productivity growth, input-output, frontier analysis, Tunisia, Croissance de la productivité totale des facteurs, tableaux entrée-sortie, frontière d’efficience, Tunisie

Restructuring And Economic Performance: The Experience Of The Tunisian Economy

This paper aims at identifying the sources of comparative advantage and the bottlenecks of the Tunisian economy. By using an activity analysis model and yearly data on the input-output structure and the factor endowments, the paper determines the evolution of the potential of the Tunisian economy between 1983 and 1996 and some of its key aspects that the industrial restructuring program of 1996 could improve or reinforce. The analysis sheds light on the scarcity of various types of labor, in particular of qualified labor. Cette étude cherche à identifier les sources d'avantage comparatif et les goulots d'étranglement en Tunisie. En utilisant un modèle d'analyse d'activités et des données annuelles de tableaux entrée-sortie et de dotations en facteurs, cette étude détermine l'évolution du potentiel de l'économie tunisienne entre 1983 et 1996 et les améliorations que pourrait y apporter le programme de mise-à-niveau industriel introduit en 1996. L'analyse montre aussi s'il existe des carences de différents types de main-d'?uvre, en particulier du travail qualifié.Tunisia, activity analysis, qualified labor, industrial restructuring program, Tunisie, analyse d'activités, travail qualifié, programme d'ajustement structurel

Combiner espaces sémantiques, structure et contraintes.

This paper presents the methods that we developed for the tasks 1 and 4 of the DEFT'14 Text Mining contest. In the task 1 the goal was to automatically categorise the literary genre of short texts, while in the task 4 the goal was to assign the session where a scientific paper is presented in a conference by analysing its content. These methods we developed rely on a common representation of the input texts in semantic spaces constructed using Random Indexing. In these high dimension spaces, each text and each term is represented a vector. For this edition of the DEFT, we tried to address the proposed tasks by designing methods that combine classical machine learning algorithms for clustering and categorisation with (i) rule based methods to represent for instance the patterns of poetic texts in the task 1 (ii) constraints solving methods to take into account the informations we had about the organisation of the sessions in the task 4. The results obtained NDCG=0.4278 (rank 2) in the task 1 and FScore=1 (rank 1) in the task 4 show the great performance of these hybrid methods.JRC.G.2-Global security and crisis managemen

On the J-test for nonnested hypotheses and Bayesian extension

Abstract Davidson and MacKinnon’s J-test was developed to test non-nested model specification. In empirical applications, however, when the alternate specifications fit the data well the J test may fail to distinguish between the true and false models: the J test will either reject, or fail to reject both specifications. In such cases we show that it is possible to use the information generated in the process of applying the J-test to implement a Bayesian approach that provides an unequivocal and acceptable solution. Jeffreys’ Bayes factors offer ways of obtaining the posterior probabilities of the competing models and relative ranking of the competing hypotheses. We further show that by using approximations of Schwarz Information Criterion and Bayesian Information Criterion we can use the classical estimates of the log of the maximum likelihood which are available from the estimation procedures used to implement the J test to obtain Bayesian posterior odds and posterior probabilities of the competing nested and non- nested specifications without having to specify prior distributions and going through the rigorous Bayesian computations.specification testing, non-nested hypotheses, Bayes factor, Bayesian Information Criteria, Marginal likelihood

To NACK or not to NACK? Negative Acknowledgments in Information-Centric Networking

Information-Centric Networking (ICN) is an internetworking paradigm that offers an alternative to the current IP\nobreakdash-based Internet architecture. ICN's most distinguishing feature is its emphasis on information (content) instead of communication endpoints. One important open issue in ICN is whether negative acknowledgments (NACKs) at the network layer are useful for notifying downstream nodes about forwarding failures, or requests for incorrect or non-existent information. In benign settings, NACKs are beneficial for ICN architectures, such as CCNx and NDN, since they flush state in routers and notify consumers. In terms of security, NACKs seem useful as they can help mitigating so-called Interest Flooding attacks. However, as we show in this paper, network-layer NACKs also have some unpleasant security implications. We consider several types of NACKs and discuss their security design requirements and implications. We also demonstrate that providing secure NACKs triggers the threat of producer-bound flooding attacks. Although we discuss some potential countermeasures to these attacks, the main conclusion of this paper is that network-layer NACKs are best avoided, at least for security reasons.Comment: 10 pages, 7 figure

Mechanisms Contributing to the Generation of Mayer Waves

Mayer waves may synchronize overlapping propriobulbar interneuronal microcircuits constituting the respiratory rhythm and pattern generator, sympathetic oscillators, and cardiac vagal preganglionic neurons. Initially described by Sir Sigmund Mayer in the year 1876 in the arterial pressure waveform of anesthetized rabbits, authors have since extensively observed these oscillations in recordings of hemodynamic variables, including arterial pressure waveform, peripheral resistance, and blood flow. Authors would later reveal the presence of these oscillations in sympathetic neural efferent discharge and brainstem and spinal zones corresponding with sympathetic oscillators. Mayer wave central tendency proves highly consistent within, though the specific frequency band varies extensively across, species. Striking resemblance of the Mayer wave central tendency to the species-specific baroreflex resonant frequency has led the majority of investigators to comfortably presume, and generate computational models premised upon, a baroreflex origin of these oscillations. Empirical interrogation of this conjecture has generated variable results and derivative interpretations. Sinoaortic denervation and effector sympathectomy variably reduces or abolishes spectral power contained within the Mayer wave frequency band. Refractorines of Mayer wave generation to barodeafferentation lends credence to the hypothesis these waves are chiefly generated by brainstem propriobulbar and spinal cord propriospinal interneuronal microcircuit oscillators and likely modulated by the baroreflex. The presence of these waves in unitary discharge of medullary lateral tegmental field and rostral ventrolateral medullary neurons (contemporaneously exhibiting fast sympathetic rhythms [2-6 and 10 Hz bands]) in spectral variability in vagotomized pentobarbital-anesthetized and unanesthetized midcollicular (i.e., intercollicular) decerebrate cats supports genesis of Mayer waves by supraspinal sympathetic microcircuit oscillators. Persistence of these waves following high cervical transection in vagotomized unanesthetized midcollicular decerebrate cats would seem to suggestspinalsympathetic microcircuit oscillators generate these waves. The widespread presence of Mayer waves in brainstem sympathetic-related and non-sympathetic-related cells would seem to betray a general tendency of neurons to oscillate at this frequency. We have thus presented an extensive and, hopefully cohesive, discourse evaluating, and evolving the interpretive consideration of, evidence seeking to illumine our understanding of origins of, and insight into mechanisms contributing to, the genesis of Mayer waves. We have predicated our arguments and conjectures in the substance and matter of empirical data, though we have occasionally waxed philosophical beyond these traditional confines in suggesting interpretations exceeding these limits. We believe our synthesis and interpretation of the relevant literature will fruitfully inspire future studies from the perspective of a more intimate appreciation and conceptualization of network mechanisms generating oscillatory variability in neuronal and neural outputs. Our evaluation of Mayer waves informs a novel set of disciplines we term quantum neurophysics extendable to describing subatomic reality. Beyond informing our appreciation of mechanisms generating sympathetic oscillations, Mayer waves may constitute an intrinsic property of neurons extant throughout the cerebrum, brainstem, and spinal cord or reflect an emergent property of interactions between arteriogenic and neuronal oscillations.Peer reviewe