Approximate pattern matching in a pattern database system

This work is concerned with the organization of a large database of binary pictures (normalized for size, rotation and position) and with the efficient “inexact match” of an input pattern against the whole database. Current techniques in pattern analysis use matching algorithms without any regard to the global organization of the storage representations of the models they are to match. Consequently, the algorithms are only practical for small databases. This paper discusses the design of a pattern database system and the economy that it provides for the matching problem. The database organization is based on the quad-tree representation of binary patterns. Given an arbitrary decomposition D (or partition) of a pattern P and an arbitrary function f on the pattern, we repeatedly apply f on D(P), D(D(P))P, … to obtain higher and higher levels of abstraction f(D)(P)), f(D(D(P))), … of the pattern. The computed values obtained after the jth application of f are used to label the ith level of the pyramid. The specific representation used in this paper is called the sum-quad-tree, in which each level of the tree stores the sum of the labels of its sons. The lowest level of the sum-quad-tree corresponds to the individual pixels and is the nth level (i.e. node m at level n implies v(m) = 0 or v(m) = 1). Nodes at the jth level of the sum-quad-tree correspond to sums of 2^n?j × 2^n?j picture points, so that the 0th level contains the number of 1's in the pattern. The pyramid representation is used as a hierarchical (n-level) indexing scheme of the database. The advantage of this organization is that the matching algorithms presented reject most of the patterns in the database by utilizing the relatively small in size index tables and thus avoid the overhead of unnecessary CPU time and $\text{I}\text{O}$ operation between main memory and secondary storage.     

The 1981–1984 automobile fuel economy standards—Can they be achieved?

The current automobile fuel economy standards were established in June 1977. Several studies completed since then recommended that the Department of Transportation (DOT) modify the current schedule. However, all of the studies were completed before the 1979 gasoline shortage.This paper compares the studies performed to assess alternative schedules and identifies major differences. Major differences among the studies include the definition of‘economic practicability’, cost estimates, estimates of automobile sales losses, and the impact of EPA test procedures.The results of the comparison, along with an analysis of the mix of new cars sold and used car prices since the gasoline shortage, are used to determine if the current schedule can be achieved. Observations regarding improvements to the fuel economy programme for establishing post-1985 standards are also presented.     

The effects of environmental information and decision unit structure on felt tension.

Treated 4 measures of felt tension, derived from a factor analysis of the R. L. Kahn et al (1964) tension index, as variables dependent on information inputs from the environment and on the group structure of the decision unit. In an experimental simulation of a military conflict, information load and information specificity were manipulated to control the environment of 48 3-man decision groups (72 ROTC students and 72 US Air Force Academy cadets) structured as either committees of coequals or 2-level hierarchies. Salient findings from the analysis suggest that (a) "role overload tension" is positively related to information load, while "generalized tension" is positively related to information load only when information specificity is low; (b) "information deprivation tension" is inversely related to information specificity for bureaucratically structured groups but not for unstructured groups, and "generalized tension" is inversely related to information specificity only at high information loads; and (c) "role overload tension" and "role ambiguity tension" are lower in groups with a structured hierarchy. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The decomposition reaction path of a linear PFPAE under tribological conditions

It has previously been shown using ¹⁹F nuclear magnetic resonance (NMR) spectroscopy that a linear perfluoropolyalkyl ether (PFPAE) fluid undergoes decomposition by a disproportionation reaction mechanism to form acid fluorides when heated in the presence of aluminum chloride. It is shown in this study that the same linear PFPAE fluid decomposes by the same reaction mechanism to form the same acid fluorides when heated at 345°C in the presence of dry air and bearing steels. Then, it is shown that these acid fluorides readily undergo hydrolysis to carboxylic acids when they are exposed to atmospheric moisture. Finally, carboxylic acids were detected in highly stressed linear PFPAE fluids exposed to the atmosphere after recovery from fatigue testing experiments. Therefore, it is concluded that under real tribological conditions, linear PFPAE fluids initially decompose in the presence of bearing steels by a disproportionation reaction mechanism to form acid fluorides which subsequently react with atmospheric moisture to form carboxylic acids. This revised version was published online in August 2006 with corrections to the Cover Date.     

On the Use of Enterprise Models

This paper presents the results of a field study designed to determine how enterprise models are used. The paper begins with an introduction to enterprise models then provides an overview of the survey method used. No known empirical studies have been conducted to determine how enterprise models actually are used by industry. The research is designed to answer this question. A screening sample and complete web-based survey of 72 enterprise modelers was conducted. The primary research question of this survey was on the use of enterprise models, with particular focus on the three dimensions of living models: scope, enactment, and dynamicity. Half the respondents claim that their enterprise models were of their entire division, multiple divisions, and even multiple enterprises. It is encouraging to see that enterprise models are used on such a wide scope. The enactment of the enterprise models was not as large as was expected. Of the respondents, 75% claimed that their models did not receive information from the enterprise more frequently than quarterly. The same was true for how often the models provided information to the enterprise. Seventy-five percent did not update their models more than five times (although, 32% did update the model three to five times). Finally, additional areas of research are proposed.     

Determining health risks associated with disinfectants and disinfection by-products: research needs

In order to minimize the levels of potentially toxic disinfectants and disinfection by-products in treated water while maintaining adequate protection against microbiological contamination, the total risks associated with disinfection have to be measured and compared with the risks from microbial agents. Because much work has already been carried out on chlorination and its by-products, it is recommended that research focus on major disinfection alternatives, i.e., ozonation, chloramination, carbon dioxidation, and the most practical combinations of these options. The primary research needs are (1) assessment of the relative toxicological hazards of the disinfectants and their by-products and (2) development of biologically based models for the dose-response relationships of these chemicals.     

Comparison of Enterococcus measurements in freshwater at two recreational beaches by quantitative polymerase chain reaction and membrane filter culture analysis

Cell densities of the fecal pollution indicator genus, Enterococcus, were determined by a rapid (3 h or less) quantitative polymerase chain reaction (QPCR) analysis method in 100 ml water samples collected from recreational beaches on Lake Michigan and Lake Erie during the summer of 2003. Measurements by this method were compared with counts of Enterococcus colony-forming units (CFU) determined by Method 1600 membrane filter (MF) analysis using mEI agar. The QPCR method had an estimated 95% confidence, minimum detection limit of 27 Enterococcus cells per sample in analyses of undiluted DNA extracts and quantitative analyses of multiple lake water samples, spiked with known numbers of these organisms, gave geometric mean results that were highly consistent with the spike levels. At both beaches, the geometric means of ambient Enterococcus concentrations in water samples, determined from multiple collection points during each sampling visit, showed approximately lognormal distributions over the study period using both QPCR and MF analyses. These geometric means ranged from 10 to 8548 cells by QPCR analysis and 1-2499 CFU by MF culture analysis in Lake Michigan (N=56) and from 8 to 8695 cells by QPCR and 3-1941 CFU by MF culture in Lake Erie (N=47). Regression analysis of these results showed a significant positive correlation between the two methods with an overall correlation coefficient (r) of 0.68.