Accurate Depth of Field Simulation in Real Time

We present a new post processing method of simulating depth of field based on accurate calculations of circles of confusion. Compared to previous work, our method derives actual scene depth information directly from the existing depth buffer, requires no specialized rendering passes, and allows easy integration into existing rendering applications. Our implementation uses an adaptive, two‐pass filter, producing a high quality depth of field effect that can be executed entirely on the GPU, taking advantage of the parallelism of modern graphics cards and permitting real time performance when applied to large numbers of pixels.     

Expressing the equivalence of non‐isothermal and isothermal heat sterilization processes

Currently, the sterility of heat‐processed food and pharmaceuticals is assessed in terms of an F₀ value, based on the equivalence of the heat treatment to an isothermal process at a reference temperature. This F₀ value, however, has a meaning if, and only if, the inactivation kinetics of the targeted spores (or cells) follow a first‐order relationship and the temperature dependence of the D value, the reciprocal of the rate constant, is log‐linear. There is growing evidence that these conditions are not satisfied by many spores, including those of Clostridium botulinum and vegetative cells. Consequently, a replacement for the F₀ value is proposed in the form of a momentary equivalent time at the reference temperature based on the actual survival pattern of the spores, which need not be log‐linear. This equivalent time can be calculated together with the theoretical survival ratio in real time, thus enabling an operator to monitor the lethality of ongoing industrial heat processes. The concept is demonstrated with published survival data of C. botulinum, for which the Weibullian and log‐logistic models served as primary and secondary models, respectively. The safety factor according to the proposed method is in the number of added minutes of processing, beyond the theoretical time needed to reduce the survival ratio of the targeted spores or cells to a level that would produce practical (or commercial) sterility. Copyright © 2006 Society of Chemical Industry     

Automated Support for Building and Extending Expert Models

Building a knowledge-based system is like developing a scientific theory. Although a knowledge base does not constitute a theory of some natural phenomenon, it does represent a theory of how a class of professionals approaches an application task. As when scientists develop a natural theory, builders of expert systems first must formulate a model of the behavior that they wish to understand and then must corroborate and extend that model with the aid of specific examples. Thus there are two interrelated phases of knowledge-base construction: (1) model building and (2) model extension. Computer-based tools can assist developers with both phases of the knowledge-acquisition process. Workers in the area of knowledge acquisition have developed computer-based tools that emphasize either the building of new models or the extension of existing models. The PROTÉGÉ knowledge-acquisition system addresses these two activities individually and facilitates the construction of expert systems when the same general model can be applied to a variety of application tasks.     

Clinical psychopathologic symptoms in neuropsychologically impaired and intact schizophrenics.

Examined the differential prevalence of 10 major dimensions of psychotic and affective signs (e.g., auditory hallucinations, delusions of control, excitement/agitation, catatonic and bizarre behavior) and symptoms in 18 neuropsychologically impaired and 30 neuropsychologically intact schizophrenics who were diagnosed under Research Diagnostic Criteria. Assessments were based on the Present State Examination and on the Luria-Nebraska Neuropsychological Battery. Results show that the neuropsychologically impaired Ss had a lower incidence of delusions of reference and persecution and a diminished capacity for insight compared to neuropsychologically unimpaired Ss. Findings are discussed in terms of a frontal lobe dysfunction hypothesis of schizophrenic psychopathology. (3 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Meeting housing needs through the market: An assessment of housing policies and the supply/demand balance in France and Great Britain

In both Britain and France, for the last 15 years or so, housing policy has become more market‐orientated. This paper examines what this has meant for the balance between supply and demand and for progress in meeting housing needs. Current projections for how housing needs and the demand/supply balance will develop in the 1990s are also analysed. For each country, the determinants of housing demand, both demographic and economic, and the supply position in both the private and public sectors, are examined. Several common issues are identified: the existence of unmet housing needs, problems of indebtedness, the limits to the expansion of owner occupation, problems of social housing finance, and concerns about the decline of the private rented sector. There are also important differences between the two countries: housing output remains at a higher level in France than in Britain; deregulation of housing finance has gone further in Britain than in France; and in France there remains a greater recognition by government that housing is a national responsibility. But in both countries, the ‘marketisation’ of housing policy has meant that housing outcomes have become more dependent on factors external to the housing system.