Investigation of path requirements in a water distribution network

One approach in addressing reliability aspects of water distribution networks is to require two paths from a source to a demand point. The problem faced in these approaches is to define the paths and to what degree there is, or should be, dependency, i.e., common links in those paths. This study attempts to examine the implications associated with these dependency issues. Using an optimization formulation which includes minimum path constraints, various path requirements ranging from a single path to two distinct, independent paths (to each demand node) are investigated.     

Armstrong axioms and Boyce-Codd-Heath Normal Form under bag semantics

The theory of functional dependencies is based on relations, i.e. sets of tuples. Over relations, the class of functional dependencies subsumes the class of keys. Commercial database systems permit the storage of bags of tuples where duplicate tuples can occur. Over bags, keys and functional dependencies interact differently from how they interact over relations.We establish finite ground axiomatizations of keys and functional dependencies over bags, and show a strong correspondence to goal and definite clauses in classical propositional logic. We define a syntactic Boyce-Codd-Heath Normal Form condition, and show that the condition characterizes schemata that will never have any redundant data value occurrences in their instances. The results close the gap between the existing set-based theory of data dependencies and database practice where bags are permitted.     

Geometrically Non-Linear Rapid Heating of Temperature-Dependent Circular FGM Plates

Based on the uncoupled thermoelasticity assumptions, axisymmetric thermally induced vibrations of a circular plate made of functionally graded materials (FGMs) are analyzed. Each thermomechanical property of the circular plate is assumed to be functions of temperature and thickness coordinate. Solution of the transient one-dimensional heat conduction equation with the arbitrary type of time-dependent boundary conditions is carried out employing the central finite difference method combined with the Crank–Nicolson time marching scheme. Afterwards, with the establishment of the associated Hamilton's principle and the accountancy of the von Kármán type of geometrical non-linearity, the motion equations are obtained with the aid of the conventional multi-term Ritz method. The solution of highly coupled non-linear motion equations is obtained utilizing a hybrid iterative Newton–Raphson–Newmark scheme. After validating the developed computer code, some parametric studies are accomplished to show the influences of various involved parameters. It is shown that temperature dependency, geometrical non-linearity, plate thickness, power law index, and the type of thermal in-plane and out-of-plane mechanical boundary conditions, all affect the temporal evolution of plate characteristics.     

Sequential analysis of the effects of naltrexone on the environmental meditation of self-injurious behavior.

Accumulated evidence shows that biology and the environment can mediate self-injurious behavior (SIB) in persons with mental retardation. Whether pharmacological treatment alters the environmental mediation of self-injury is unclear. Opioid antagonist effects on sequential dependencies for self-injury were studied in the context of experimental single-subject double-blind placebo-controlled designs. Direct observational data were collected for 4 adult subjects in real time on daily rate of SIB and staff interactions. Clinically significant reductions (i.e., ≥ 33%) in SIB rate were observed for 3 of the 4 subjects. For all subjects, the magnitude of the sequential dependency between staff behavior and self-injury was significantly greater during treatment with naltrexone than during treatment with a placebo. Results are discussed in relation to behavioral mechanisms of action regulating medication effects for self-injury. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An Empirical Approach to Spanish Anaphora Resolution

This paper documents the development of an empirically-basedsystem implemented in Prolog that automatically resolves severalkinds of anaphora in Spanish texts. These are pronominalreferences, surface-count anaphora, one-anaphora and ellipticalzero-subject constructions (i.e., sentences that omit theirpronominal subject). The resolution is based onrepresentations resulting from either partial or full parsing. Thesystem developed can also work on the output of a POStagger or with different dictionaries, without changing thegrammar. This grammar represents the syntactic information of eachlanguage by means of the Slot Unification Grammar formalism. The different kinds of information used for anaphora resolution in full and partial parsing are shown, as wellas evaluation results. The system has been adapted toEnglish texts, obtaining encouraging results that prove that itcan be applied with only a very few refinements to other languagesas well as Spanish and English. In addition, the differencesbetween English and Spanish anaphora are noted.     

Multi-storey timber buildings: breaking industry path dependency

The Swedish legal restriction on construction of multi-storey timber buildings was imposed in 1888 and repealed in 1994. The subsequent emergence of such a timber building system in Sweden is analysed in the context of the existing concrete-based construction system. The characteristics of the construction industry and its path dependency over the past century hamper the development of a timber building system. However, government policies and funding, the wood industry's interest in an enhanced market for value-added wood products, and involvement of the wood research community has helped develop such a construction system. Investments in knowledge creation, incentives for the entry of new firms, and increased prefabrication may facilitate a transition from this formative phase to a growth phase in the diffusion of timber buildings.

En Suède, les restrictions juridiques frappant la construction de bâtiments en bois de plusieurs étages ont été édictées en 1888 et annulées en 1994. L'auteur analyse l'arrivée résultante d'un tel système de construction en bois en Suède face à la construction en béton qui existe actuellement. Les caractéristiques de l'industrie du bâtiment et sa dépendance au chemin au cours du siècle dernier empêchent le développement d'un système de construction en bois. Toutefois, les politiques officielles et les financements ainsi que les intérêts de l'industrie du bois dans un marché amélioré pour des produits en bois à valeur ajoutée et l'engagement des chercheurs dans le domaine du bois ont aidé à développer un tel système de construction. Les investissements dans la création du savoir, les incitations à l'arrivée de nouvelles entreprises et l'augmentation de la préfabrication peuvent faciliter le passage de cette phase de formation à une phase de croissance à la diffusion des bâtiments en bois.

Mots clés: système d'innovation, restriction, bâtiments de plusieurs étages, dépendance au chemin, systèmes technologiques, charpente en bois, bâtiments en bois, Suède