Non Parametric Distributed Inference in Sensor Networks Using Box Particles Messages

This paper deals with the problem of inference in distributed systems where the probability model is stored in a distributed fashion. Graphical models provide powerful tools for modeling this kind of problems. Inspired by the box particle filter which combines interval analysis with particle filtering to solve temporal inference problems, this paper introduces a belief propagation-like message-passing algorithm that uses bounded error methods to solve the inference problem defined on an arbitrary graphical model. We show the theoretic derivation of the novel algorithm and we test its performance on the problem of calibration in wireless sensor networks. That is the positioning of a number of randomly deployed sensors, according to some reference defined by a set of anchor nodes for which the positions are known a priori. The new algorithm, while achieving a better or similar performance, offers impressive reduction of the information circulating in the network and the needed computation times

The NEG elements in clause structures

This article deals with the syntax of sentential negative elements in a number of languages. We start by investigating three kinds of sentential negative elements in Arabic. We argue that these elements occupy different positions in the hierarchic order of clause structure. Negative elements occur in positions higher than TNS, or between TNS and AG Rs, or project internal to the Predicate Phrase. Analysis of Arabic negative clauses reveals that although NEG elements project as phrasal heads, they are closely associated with TNS and AGRs. We propose a hypothesis of Adjunction movement to TNS/ NEG motivated by morphological requirement of the elements involved. Movements, which should apply before Spell-out, are necessary for Checking theory. The same procedure has been applied to negative clauses in English, French, Italian, etc. We claim that sentential NEG elements share in their essence certain simple properties at least in the languages investigated here

Évolution temporelle de l’envasement des retenues de barrages de Tunisie

La mobilisation et l’exploitation des eaux de surface sont des pratiques anciennes en Tunisie. Les aménagements réalisés au cours du siècle dernier sont exposés à un alluvionnement plus ou moins accéléré. La capacité de stockage des retenues des barrages est sujette à une réduction progressive au cours du temps. Cette perte de capacité, parfois élevée, dépasse les prévisions de l’alluvionnement de la retenue. La quantification des sédiments piégés se base soit sur les bilans de matière solide à l’échelle d’une retenue, soit sur des levés bathymétriques ou topographiques. Les Modèles Numériques de Terrain (MNT) des retenues sont de plus en plus utilisés. Les différentes évaluations sont entachées d’une incertitude. Les retenues des barrages tunisiens perdent annuellement 0,5 % à 1 % de leur capacité par alluvionnement. L’analyse des résultats de mesures montre que l’alluvionnement est lié à l’hydrologie du cours d’eau, à la gestion de la réserve d’eau et aux manoeuvres de dévasement. La comparaison entre les résultats de mesures de l’alluvionnement et les prévisions des projets met en évidence des différences parfois relativement importantes qui sont dues au régime hydrologique des cours d’eau. En effet, une crue exceptionnelle peut provoquer un alluvionnement nettement supérieur à la moyenne annuelle en régime hydrologique normal. Les retenues méandriformes sont comblées rapidement alors que les retenues linéaires offrent la possibilité de soutirage de quantités importantes de sédiments. Les moyennes annuelles des pertes de capacité des barrages en exploitation et des barrages projetés jusqu’à 2010 permettent de quantifier les volumes des sédiments piégés à 500 Mm3. En 2030, la perte de capacité de stockage des barrages en exploitation pourrait atteindre 43 % de leur capacité initiale. Les aménagements amont et les travaux de conservation des eaux et des sols permettent de réduire le taux d’alluvionnement et de prolonger la durée de vie des grands réservoirs.The mobilization and exploitation of surface water are ancient practices in Tunisia. Installations carried out during last century are exposed to a greater or lesser degree of accelerated silting. The storage capacity of reservoirs is progressively reduced over the course of time. This sometimes accelerated loss of capacity of reserves by silting exceeds the forecasts of hydraulic installation projects. The quantification of trapped sediments is based on the assessment of a reservoir’s retained solid matter, either by bathymetric or topographic rising or by Digital Models of Grounds (DMG) corresponding to different dates. These various evaluations of the sediments trapped in reservoirs are, however, sullied with uncertainty. Tunisian reservoirs lose 0.5% to 1% of their storage capacity to silting annually. The analysis of the results presented in this study shows that silting is related to three factors: river hydrology, water reserve management and dredging operations. The comparison between the silting results and the project forecasts highlights relatively significant differences which may be due to river hydrology. Indeed a significant rising in water level can cause an increase in silting above the annual average found during normal hydrological modes. While meandering reservoirs are quickly filled with sediment, linear reservoirs can undergo dredging to remove a significant quantity of sediment. The annual averages in storage capacity losses of the dam under exploitation and its projections up to the year 2010 enable us to quantify the volumes of the sediment trapped as 500 Mm3. In 2030, the loss of storage capacity of the studied reservoirs may reach 43% of their initial storage capacities. Installations upstream and soil and water conservation efforts may reduce the rate of silting and prolong the lifespan of large dams

Experimental and quantum chemical calculations on corrosion inhibition of mild steel by two furan derivatives

Two furan derivatives namely 5-methylfurfurylamine (MFA) and furfurylamine (FAM) were investigated as corrosion inhibitors for mild steel in 1 M HCl. The corrosion inhibition efficiencies (IE) were measured at 0.005M of the inhibitors using electrochemical potentiodynamic polarization measurements. The studied furan derivatives inhibit mild steel corrosion in acidic medium. The MFA shows higher inhibition efficiency of 84.77% compared to FAM of 41.75%. Quantum chemical calculations were performed at the B3LYP/6-311++G(d,p) level of density functional theory (DFT). Several quantum parameters were calculated to study the correlation between the molecular structures and the corrosion inhibition performance of the inhibitors. The MFA inhibitor shows higher HOMO energy, softness (S), fraction of electrons transferred (ΔN), and lower energy gap (ΔE) compared to the FAM. This result indicates a better corrosion inhibition performance of the MFA inhibitor. The results show that the calculated values of the quantum parameters using DFT calculations are consistent with the experimental findings

Hydro-institutional mapping in the Steelpoort River Basin, South Africa

River basins / Institutions / Organizations / Private sector / Public sector / Local government / Mapping / Water resource management / Water policy / Legislation / Rural women / Constraints / Groundwater / Surface water / Water quality / Water use / Water users / Dams / Reservoirs / Large-scale systems / Irrigation management / Industrialization / Case studies / Operations / Maintenance / Canals / Conflict / Farmer-agency interactions / Policy / Water supply / Rural development