Characterization of indoor air pollution

This is a review paper addressing the current state-of-the-art. Concerns that motivate studies of the indoor environment are reviewed in the introduction. The source and typical diurnal variations of the concentration of several air contaminants are discussed in the section on characterization. A dynamic model is described in the section on indoor air quality modeling. Indoor air pollution control techniques are addressed in the last section.     

NEIGHBORHOOD APPROACHES TO URBAN CAPACITY BUILDING

The authors argue that the solution of urban problems requires resources and powers far beyond those available to most local governments. Only through partnerships of all relevant actors—public officials, businessmen and neighborhood residents—can such issues be dealt with. Yet, partnerships are neither simple nor inevitable. They require hard work and usually the development of the capacities of all involved. Such capacity building for partnerships is on three levels: the development of the individual capacity to play partnership roles; the creation of interactive partnerships operating as local problem solvers; and the fostering of inter-partnership networks. Neighborhoods are seen as the building blocks of cities, serving as a locality of scale upon which the citizen can base his concerns and actions and within which partnerships can operate effectively. Specific recommendations are made, utilizing this policy context to build capacity for partnerships at the neighborhood level, particularly with regard to the Intergovernmental Personnel Act.     

Long-term recovery of pressurized water reactors following a large break loss-of-coolant accident

The U.S. Nuclear Regulatory Commission recently identified a possible safety concern for pressurized water reactors. Following the reflood phase of a large break loss-of-coolant accident, long-term cooling of the reactor core may not be ensured. Specifically, the concern is that, for a pump discharge cold leg break, the loop seals in the reactor coolant pump suction piping will refill with liquid and the post-reflood steam production may depress the liquid levels in the downflow sides of the loop seals. A loop seal depression would cause a corresponding depression of the core liquid levels and possibly a fuel rod heatup in the upper core region. This paper is intended as an introduction of the safety issue that: (1) describes the important aspects of the problem, (2) provides an initial analysis of the consequences, and (3) discusses ongoing work in this area. Because the elevation of the loop seals is near the mid-core elevation in plants of Westinghouse design, the concern is greatest for those plants. There is less concern for most plants of Combustion Engineering design, and likely no concern for plants of Babcock and Wilcox design. This issue was addressed by employing both steady-state and transient systems analysis approaches. Two approaches were used because of uncertainties regarding actual reactor coolant system behavior during the post-reflood period. The steady-state approach involved the development and application of a simple computer program to investigate reactor coolant system behavior assuming quiescent post-reflood conditions. The transient systems approach involved investigating this behavior using the RELAP5/MOD2 computer code and a comprehensive RELAP5 model of a Westinghouse pressurized water reactor. The steady-state analysis indicated only a moderate fuel rod heatup is possible. The transient systems analysis indicated boiling and condensation-induced flow oscillations are sufficient to prevent fuel rod heatup. Analysis uncertainties are discussed.     

Fitting parameterized three-dimensional models to images

Model-based recognition and motion tracking depend upon the ability to solve for projection and model parameters that will best fit a 3-D model to matching 2-D image features. The author extends current methods of parameter solving to handle objects with arbitrary curved surfaces and with any number of internal parameters representing articulation, variable dimensions, or surface deformations. Numerical stabilization methods are developed that take account of inherent inaccuracies in the image measurements and allow useful solutions to be determined even when there are fewer matches than unknown parameters. The Levenberg-Marquardt method is used to always ensure convergence of the solution. These techniques allow model-based vision to be used for a much wider class of problems than was possible with previous methods. Their application is demonstrated for tracking the motion of curved, parameterized objects     

Word-fragment cuing: The lexical search hypothesis.

In four experiments we evaluated aspects of the hypothesis that word-fragment completion depends on the results of lexical but not semantic search. Experiment 1 showed that the number of meaningful associates linked to a studied word does not affect its recovery when the test cue consists of letters and spaces for missing letters. Experiments 2 and 3 showed retroactive interference effects in fragment completion when words in a second list were lexically related to words in a first list but not when the words in the second list were meaningfully related. Experiment 4 indicated that for studied words, instructions to search at the word level facilitated completion performance and that instructions to generate letters to fill missing spaces had no effect. Other findings indicate that completion was affected by the number of words lexically related to the fragment and by the number of letters missing from the fragment. In general, experimental manipulations that focused on lexical characteristics were effective, and those that focused on semantic characteristics were ineffective. The findings support the conclusion that word fragments engender a lexical search process that does not depend on retrieving encoded meaning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Formant labelling using pole-focused spectra

An algorithm is introduced which labels formants from the peaks of pole-focused spectra. A clustering procedure is first used to produce line segments of possible formants. These can be considered as anchor traces for the later processing. Rule-based labelling is then applied to provide final formant trace estimates. Experimental results show that the proposed algorithm offers improved formant labelling accuracy.