نتایج جستجو برای: causal models

تعداد نتایج: 961889  

2014
J. Scott Armstrong

Many researchers appear to operate under the impression that causal models lead to more accurate forecasts than those provided by naive models (or “projections”). This study was based on the premise that causal models lead to better forecasts than do naive models in certain situations. The key element of these situations is that there are “large changes.” One situation where large changes might...

2007
Philippe Leray Stijn Meganck Sam Maes Bernard Manderick

Several paradigms exist for modeling causal graphical models for discrete variables that can handle latent variables without explicitly modeling them quantitatively. Applying them to a problem domain consists of different steps: structure learning, parameter learning and using them for probabilistic or causal inference. We discuss two well-known formalisms, namely semi-Markovian causal models a...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شیراز - دانشکده علوم 1391

مدلهای گارچ در فضاهای هیلبرت پایان نامه حاضر شامل دو بخش می باشد. در قسمت اول مدلهای اتورگرسیو تعمیم یافته مشروط به ناهمگنی واریانس در فضاهای هیلبرت را معرفی، مفاهیم ریاضی مورد نیاز در تحلیل این مدلها در دامنه زمان را مطرح کرده و آنها را مورد بررسی قرار می دهیم. بر اساس پیشرفتهایی که اخیرا در زمینه تئوری داده های تابعی و آماره های عملگری ایجاد شده است، فرآیندهایی که دارای مقادیر در فضاهای ...

2009
Rosalyn J. Moran Klaas E. Stephan T. Seidenbecher H.-C. Pape Raymond J. Dolan Karl J. Friston

In this paper, we describe a dynamic causal model (DCM) of steady-state responses in electrophysiological data that are summarised in terms of their cross-spectral density. These spectral data-features are generated by a biologically plausible, neural-mass model of coupled electromagnetic sources; where each source comprises three sub-populations. Under linearity and stationarity assumptions, t...

Journal: :Biological research 2007
Olivier David

Dynamic Causal Modelling (DCM) and the theory of autopoietic systems are two important conceptual frameworks. In this review, we suggest that they can be combined to answer important questions about self-organising systems like the brain. DCM has been developed recently by the neuroimaging community to explain, using biophysical models, the non-invasive brain imaging data are caused by neural p...

2004
Rasa Jurgelenaite Peter J. F. Lucas

The assessment of a probability distribution that is associated with a Bayesian network is a challenging task, even if its topology is sparse. Special probability distributions, based on the notion of causal independence, have therefore been proposed, as these allow defining a probability distribution in terms of Boolean combinations of local distributions. In Bayesian networks which need to mo...

Journal: :Issues in mental health nursing 2001
J S Kim J Kaye L K Wright

This article explains causal relationships in conceptual models of mental health phenomena. Direct, moderating, mediating, and reciprocal effects among variables are defined, appropriate statistical analyses are described, and the correct interpretations of moderating versus mediating effects are discussed. Examples are provided that will help the reader to distinguish between moderating and me...

1982
Drew McDermott Ruven E. Brooks

Arby is a software for writing expert electronic systems system or higher order language systems to do diagnosis in . As such, it is similar to EMYCIN (van &lle 1962) in application, but quite different in design. It is rule-based to an extent, but the rules are written in predicate calculus. It resembles Caduceus (Pople 1977) in its me&anisms for refining and combining hypotheses.

2017
QINGYUAN ZHAO

Abstract. Starting from the observation that Friedman’s partial dependence plot has exactly the same formula as Pearl’s back-door adjustment, we explore the possibility of extracting causal information from black-box models trained by machine learning algorithms. There are three requirements to make causal interpretations: a model with good predictive performance, some domain knowledge in the f...

2009
Klaas E. Stephan Marc Tittgemeyer Thomas R. Knösche Rosalyn J. Moran Karl J. Friston

Functional integration in the brain rests on anatomical connectivity (the presence of axonal connections) and effective connectivity (the causal influences mediated by these connections). The deployment of anatomical connections provides important constraints on effective connectivity, but does not fully determine it, because synaptic connections can be expressed functionally in a dynamic and c...

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