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San Francisco, CA, United States

Quantal Inc. | Date: 1998-12-29

computer software for portfolio development, management and analysis in the investment and financial area.

Quantal Inc. | Date: 1997-07-15

computer software for use in the investment and financial area for measuring and managing the risk of domestic and international portfolios of securities and optimizing the combination of securities in the portfolios to achieve the best risk-return tradeoff.

Robson B.,Quantal Inc. | Robson B.,St. Matthews University | Robson B.,University of Wisconsin - Stout | Caruso T.P.,Quantal Inc. | And 3 more authors.
Computers in Biology and Medicine | Year: 2013

Mining biomedical and pharmaceutical data generates huge numbers of interacting probabilistic statements for inference, which can be supported by mining Web text sources. This latter can also be probabilistic, in a sense described in this report. However, the diversity of tools for probabilistic inference is troublesome, suggesting a need for a unifying best practice. Physicists often claim that quantum mechanics is the universal best practice for probabilistic reasoning. We discuss how the Dirac notation and algebra suggest the form and algebraic and semantic meaning of XML-like Web tags for a clinical and biomedical universal exchange language formulated to make sense directly to the eye of the physician and biomedical researcher. © 2013 Elsevier Ltd. Source

Robson B.,St. Matthews University | Robson B.,University of Wisconsin - Stout | Robson B.,Quantal Inc.
Computers in Biology and Medicine | Year: 2014

We recently introduced the concept of a Hyperbolic Dirac Net (HDN) for medical inference on the grounds that, while the traditional Bayes Net (BN) is popular in medicine, it is not suited to that domain: there are many interdependencies such that any "node" can be ultimately conditional upon itself. A traditional BN is a directed acyclic graph by definition, while the HDN is a bidirectional general graph closer to a diffuse "field" of influence. Cycles require bidirectionality; the HDN uses a particular type of imaginary number from Dirac's quantum mechanics to encode it. Comparison with the BN is made alongside a set of recipes for converting a given BN to an HDN, also adding cycles that do not usually require reiterative methods. This conversion is called the P-method. Conversion to cycles can sometimes be difficult, but more troubling was that the original BN had probabilities needing adjustment to satisfy realism alongside the important property called "coherence". The more general and simpler K-method, not dependent on the BN, is usually (but not necessarily) derived by data mining, and is therefore also introduced. As discussed, BN developments may converge to an HDN-like concept, so it is reasonable to consider the HDN as a BN extension. © 2014 Elsevier Ltd. Source

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