LRR Focus: Privatizing Lithuania\u27s Water

[Excerpt] Perhaps nothing is more critical to the maintenance of public health than the supply of clean water. All of the lives saved through modern medicine account for no more than a drop in the bucket when compared to the number of lives saved through improved sanitation and the presence of a steady supply of clean water. So when commercial values begin to be applied to water treatment and distribution, as they were in Lithuania in the past few years, the implications are potentially deadly

Off-design considerations through the properties of some pressure-ratio line of radial inflow turbines

Radial turbines are commonly used in applications involving operation through severe off-design conditions. The emergence of variable-geometry systems leads to the distinction between two off-design concepts: operational and geometric off-designs. Both of these operating constraints should be integrated in the design procedure. Recent developments in prediction and optimization methods allowed such an integration, but involving complex algorithms is coupled with semiempiric loss models. This paper provides a basis to obtain simple information from an existing or predesigned machine, for both operational and geometric offdesign conditions. An alternative turbine map is defined using loading and flow coefficients. A one-dimensional analysis shows that the constant pressure-ratio lines are straight lines whose slope is remarkably correlated with the pressure-ratio value and geometrical characteristics. This theoretical approach is validated against the experimentation of two machines, the linearity is observed in both cases. The direct influence of the stator configuration on the pressure-ratio lines confirms the applicability of this work to variable-geometry stages. A dimensionless cross-section of the stator is thus defined. However, the unexpected displacement of the intercept of the pressure-ratio lines limits the application field of this method. Nevertheless, a simple performance prediction analysis is proposed for blocked mass flow operation

Bag-Level Aggregation for Multiple Instance Active Learning in Instance Classification Problems

A growing number of applications, e.g. video surveillance and medical image analysis, require training recognition systems from large amounts of weakly annotated data while some targeted interactions with a domain expert are allowed to improve the training process. In such cases, active learning (AL) can reduce labeling costs for training a classifier by querying the expert to provide the labels of most informative instances. This paper focuses on AL methods for instance classification problems in multiple instance learning (MIL), where data is arranged into sets, called bags, that are weakly labeled. Most AL methods focus on single instance learning problems. These methods are not suitable for MIL problems because they cannot account for the bag structure of data. In this paper, new methods for bag-level aggregation of instance informativeness are proposed for multiple instance active learning (MIAL). The \textit{aggregated informativeness} method identifies the most informative instances based on classifier uncertainty, and queries bags incorporating the most information. The other proposed method, called \textit{cluster-based aggregative sampling}, clusters data hierarchically in the instance space. The informativeness of instances is assessed by considering bag labels, inferred instance labels, and the proportion of labels that remain to be discovered in clusters. Both proposed methods significantly outperform reference methods in extensive experiments using benchmark data from several application domains. Results indicate that using an appropriate strategy to address MIAL problems yields a significant reduction in the number of queries needed to achieve the same level of performance as single instance AL methods

Performance Back-deduction from a Loading to Flow Coefficient Map: Application to Radial Turbine

Radial turbine stages are often used for applications requiring off-design operation, as turbocharging for instance. The off-design ability of such stages is commonly analyzed through the traditional turbine map, plotting the reduced mass-flow against the pressure-ratio, for reduced-speed lines. However, some alternatives are possible, such as the flow-coefficient (Ψ ) to loading-coefficient (φ) diagram where the pressure-ratio lines are actually straight lines, very convenient property to perform prediction. A robust method re-creating this map from a predicted Ψ−φ diagram is needed. Recent work has shown that this back-deduction quality, without the use of any loss models, depends on the knowledge of an intermediate pressure-ratio. A modelization of this parameter is then proposed. The comparison with both experimental and CFD results is presented, with quite good agreement for mass flow rate and rotational speed, and for the intermediate pressure ratio. The last part of the paper is dedicated to the application of the intermediate pressure-ratio knowledge to the improvement of the deduction of the pressure ratio lines in the Ψ−φ diagram. Beside this improvement, the back-deduction method of the classical map is structured, applied and evaluated

Two-equation modeling of turbulent rotating flows

The possibility to take into account the effects of the Coriolis acceleration on turbulence is examined in the framework of two-equation eddy-viscosity models. General results on the physical consistency of such turbulence models are derived from a dynamical-system approach to situations of time-evolving homogeneous turbulence in a rotating frame. Application of this analysis to a (k,epsilon) model fitted with an existing Coriolis correction [J. H. G. Howard, S. V. Patankar, and R. M. Bordynuik, "Flow prediction in rotating ducts using Coriolis-modified turbulence models", ASME Trans. J. Fluids Eng. 102, (1980)] is performed. Full analytical solutions are given for the flow predicted with this model in the situation of homogeneously sheared turbulence subject to rotation. The existence of an unphysical phenomenon of blowup at finite time is demonstrated in some range of the rotation-to-shear ratio. A direct connection is made between the slope of the mean-velocity profile in the plane-channel flow with spanwise rotation, and a particular fixed point of the dynamical system in homogeneously sheared turbulence subject to rotation. The general analysis, and the understanding of typical inaccuracies and misbehavior observed with the existing model, are then used to design a new model which is free from the phenomenon of blowup at finite time and able to account for both of the main influences of rotation on turbulence: the inhibition of the spectral transfer to high wave numbers and the shear/Coriolis instability

Multiple Instance Learning: A Survey of Problem Characteristics and Applications

Multiple instance learning (MIL) is a form of weakly supervised learning where training instances are arranged in sets, called bags, and a label is provided for the entire bag. This formulation is gaining interest because it naturally fits various problems and allows to leverage weakly labeled data. Consequently, it has been used in diverse application fields such as computer vision and document classification. However, learning from bags raises important challenges that are unique to MIL. This paper provides a comprehensive survey of the characteristics which define and differentiate the types of MIL problems. Until now, these problem characteristics have not been formally identified and described. As a result, the variations in performance of MIL algorithms from one data set to another are difficult to explain. In this paper, MIL problem characteristics are grouped into four broad categories: the composition of the bags, the types of data distribution, the ambiguity of instance labels, and the task to be performed. Methods specialized to address each category are reviewed. Then, the extent to which these characteristics manifest themselves in key MIL application areas are described. Finally, experiments are conducted to compare the performance of 16 state-of-the-art MIL methods on selected problem characteristics. This paper provides insight on how the problem characteristics affect MIL algorithms, recommendations for future benchmarking and promising avenues for research

Alien Registration- Carbonneau, Albert (Lewiston, Androscoggin County)

https://digitalmaine.com/alien_docs/29778/thumbnail.jp

Modèles de formation et professionnalisation de l’enseignement : analyse critique de tendances nord-américaines

- L'enseignement nord-américain, primaire et secondaire, fait l'objet d'importantes remises en question. Dans ce contexte, sa professionnalisation est vue par plusieurs comme la meilleure façon de remédier aux faiblesses qui le caractérisent et de donner un nouvel essor à l'école. Dans la poursuite de cet objectif, l'accentuation du caractère professionnel de la formation initiale des enseignants ressort comme une condition nécessaire. Dans le cadre de cette problématique, la présente analyse examine la légitimité de ce mouve- ment de professionnalisation, critique son rapport aux modèles actuels de formation initiale et aux tendances qui émergent de cet univers et, finalement, suggère un profil de composantes pour une pratique professionnelle à venir.- The field of teaching in North America, at both primary and secondary levels, has been the object of renewed questioning. For some, the way to remediate various weak- nesses and to give new spirit to the school is through a professionalization. A necessary condition in attaining this objective is to accentuate the professional character of initial teacher training. This analysis examines the legitimacy of the professionalization move- ment, criticizes the relation between this and current training models and emerging approaches, and finally, suggests a profile of various components for future professional practices.- La ensenanza norteamericana, primaria y secundaria, es objecto de impor- tantes revisiones. En este contexto, su profesionalizaciôn es vista por varios como la mejor forma de remediar las debilidades que la caracterizan y de dar un nuevo empuje a la escuela. Siguiendo este objetivo, sobresale como condiciôn necesaria el énfasis del carâc- ter profesional de la formaciôn inicial de los profesores. En el contexto de esta pro- blemâtica, el présente anâlisis examina la legitimadad de este movimiento de profesionalizaciôn, critica su relaciôn con los modelos actuates de formaciôn inicial y con las tendencias que emergen de este universo y, finalmente, sugiere un perfil de compo- nentes para una futura pratica profesional.Zusammenfassung- Das nordamerikanische Schulwesen (Volks- und hôhere Schule) wird weitgehend in Frage gestellt. Dabei wird oft die Anhebung der akademischen Ausbildung und des Statuts (die Professionalisierung) als die beste Art und Weise ange- sehen, um der Schwâchen Herr zu werden, die es kennzeichnen, und um der Schule neuen Aufschwung zu geben. In dieser Hinsicht erscheint die Hervorhebung des Fach- Charakters der Lehrerbildung wie eine notwendige Bedingung. Die vorliegende Untersuchung prùft die Rechtfertigung dieser Strômung der "Professionalisierung", beleuchtet kritisch ihr Verhâltnis zu den bestehenden Modellen der Lehrerbildung und zu den in diesem Bereich auftretenden Tendenzen, und schlàgt schliesslich einen Querschnitt der Komponenten fur eine kùnftige Fachpraxis vor