D.VI.1 Is the difference between a priori and a posteriori truth one of degree only or of kind?

2006 ◽  
pp. 198-199
Author(s):  
Gerard Manley Hopkins
Keyword(s):  
A Priori ◽  
A Posteriori ◽  
The Difference

scholarly journals Information Value Measure for Optimization of Flexible Diagnosis Programs of Technical Objects

2019 ◽  
Vol 18 (6) ◽  
pp. 1434-1461 ◽  
Author(s):  
Evgeniy Kopkin ◽  
Igor Kobzarev
Keyword(s):  
A Priori ◽  
Technical Condition ◽  
Diagnostic Information ◽  
Information Value ◽  
Technical State ◽  
A Posteriori ◽  
Automated Systems ◽  
Maximum Value ◽  
Diagnostic Signs ◽  
The Difference

Existing methods of calculating of the value of diagnostic information circulating in the automated systems of monitoring of technical condition of objects do not take into account "losses" ("gains") resulting from making “wrong” decisions when identifying this state. The purpose of the work is to develop an algorithm that allows to solve the problem of recognizing the technical state of the object being analyzed by means of dynamic programming, the value of the diagnostic information as an optimized indicator being used. The solution to the optimization problem of a diagnostic procedure is based on the use of a measure of the information value proposed by R. L. Stratonovich. It is modified according to the subject area of the technical diagnostics and in the case when the diagnostic features presented in the form of intervals on the real numerical axis are used. The maximum value of the diagnostic information is achieved by minimizing the average "losses" (maximizing the average "gains") obtained when performing tests of diagnostic signs in the process of recognizing the technical condition of an object. To solve the problem, a recurrent expression possessing a scientific novelty has been proposed. It allows to calculate the value of the information obtained when performing tests of diagnostic signs in each of the analyzed information states of the diagnostic process. In the process of the diagnostics program implementation when recognizing the technical condition of the object both “losses” and “winnings” are possible. The difference between their a priori and a posteriori means values characterizes the value of the diagnostic information numerically. The magnitude of the information value indication depends on the probabilities of the results of the diagnostic signs checks and is proportional to the difference between the a posteriori and a priori probabilities of achieving the diagnostic goal. By using the proposed solution, it is possible to synthesize the flexible diagnostics program that is optimal according to the maximum value of diagnostic information in the form of a oriented graph or sets of tests in proper sequence of their execution. This is necessary in order to recognize the specific technical state in which the object is located. The implementation of the algorithm developed is possible in the software and algorithmic support of the automated systems for monitoring the state of complex technical objects.

scholarly journals Effects of <i>a priori</i> profile shape assumptions oncomparisons between satellite NO<sub>2</sub> columns and model simulations

2020 ◽  
Author(s):  
Matthew J. Cooper ◽  
Randall V. Martin ◽  
Daven K. Henze ◽  
Dylan B. A. Jones
Keyword(s):  
Shape Factor ◽  
A Priori ◽  
Trace Gas ◽  
A Posteriori ◽  
A Priori Information ◽  
Profile Shape ◽  
Satellite Retrievals ◽  
Mass Factor ◽  
The Difference ◽  
Priori Information

Abstract. A critical step in satellite retrievals of trace gas columns is the calculation of the air mass factor (AMF) used to convert observed slant columns to vertical columns. This calculation requires a priori information on the shape of the vertical profile. As a result, comparisons between satellite-retrieved and model-simulated column abundances are influenced by the a priori profile shape. We examine how differences between the shape of the simulated and a priori profile can impact the interpretation of satellite retrievals by performing an adjoint-based 4D-Var assimilation of synthetic NO2 observations for constraining NOx emissions. We use the GEOS-Chem Adjoint model to perform assimilations using a variety of AMFs to examine how a posteriori emission estimates are affected if the AMF is calculated using an a priori shape factor that is inconsistent with the simulated profile. In these tests, an inconsistent a priori shape factor increased errors in a posteriori emissions estimates by up to 80 % over polluted regions. As the difference between the simulated profile shape and the a priori profile shape increases, so do the corresponding assimilated emission errors. This reveals the importance of using simulated profile information for AMF calculations when comparing that simulated output to satellite retrieved columns.

scholarly journals Effects of a priori profile shape assumptions on comparisons between satellite NO<sub>2</sub> columns and model simulations

2020 ◽  
Vol 20 (12) ◽  
pp. 7231-7241
Author(s):  
Matthew J. Cooper ◽  
Randall V. Martin ◽  
Daven K. Henze ◽  
Dylan B. A. Jones
Keyword(s):  
Shape Factor ◽  
A Priori ◽  
Trace Gas ◽  
A Posteriori ◽  
Profile Shape ◽  
Satellite Retrievals ◽  
Mass Factor ◽  
The Difference ◽  
Priori Information ◽  
Mean Square Errors

Abstract. A critical step in satellite retrievals of trace gas columns is the calculation of the air mass factor (AMF) used to convert observed slant columns to vertical columns. This calculation requires a priori information on the shape of the vertical profile. As a result, comparisons between satellite-retrieved and model-simulated column abundances are influenced by the a priori profile shape. We examine how differences between the shape of the simulated and a priori profiles can impact the interpretation of satellite retrievals by performing an adjoint-based four-dimensional variational (4D-Var) assimilation of synthetic NO2 observations for constraining NOx emissions. We use the GEOS-Chem adjoint model to perform assimilations using a variety of AMFs to examine how a posteriori emission estimates are affected if the AMF is calculated using an a priori shape factor that is inconsistent with the simulated profile. In these tests, an inconsistent a priori shape factor increased root mean square errors in a posteriori emission estimates by up to 30 % for realistic conditions over polluted regions. As the difference between the simulated profile shape and the a priori profile shape increases, so do the corresponding assimilated emission errors. This reveals the importance of using simulated profile information for AMF calculations when comparing that simulated output to satellite-retrieved columns.

Information gain as uncertainty reduction

1990 ◽  
Vol 55 (1) ◽  
pp. 91-96 ◽  
Author(s):  
Karel Eckschlager
Keyword(s):  
Information Content ◽  
Information Gain ◽  
A Priori ◽  
Uncertainty Reduction ◽  
A Posteriori ◽  
The Difference

It is shown that the various information content or information gain measures can be expressed in terms of the difference between the a priori and a posteriori uncertainties. Measures based on uncertainty expressed by means of variance are compared with those where the uncertainty also involves bias of the results, and it is shown that measures of the two kinds somewhat different application.

A priori/a posteriori

2017 ◽  
Author(s):  
Heinrich Schepers ◽  
Giorgio Tonelli ◽  
Rudolf Eisler
Keyword(s):  
A Priori ◽  
A Posteriori

A Critique of Modernist Synthesis in Islamic Thought

1994 ◽  
Vol 11 (4) ◽  
pp. 475-503
Author(s):  
Masudul Alum Choudhury
Keyword(s):  
Scientific Inquiry ◽  
A Priori ◽  
Scientific Investigation ◽  
Muslim World ◽  
A Posteriori ◽  
Islamic Thought ◽  
And Behavior ◽  
Muslim Scholars

Is it the realm of theoretical constructs or positive applications thatdefines the essence of scientific inquiry? Is there unison between thenormative and the positive, between the inductive and deductivecontents, between perception and reality, between the micro- andmacro-phenomena of reality as technically understood? In short, isthere a possibility for unification of knowledge in modernist epistemologicalcomprehension? Is knowledge perceived in conceptionand application as systemic dichotomy between the purely epistemic(in the metaphysically a priori sense) and the purely ontic (in thepurely positivistically a posteriori sense) at all a reflection of reality?Is knowledge possible in such a dichotomy or plurality?Answers to these foundational questions are primal in order tounderstand a critique of modernist synthesis in Islamic thought thathas been raging among Muslim scholars for some time now. Theconsequences emanating from the modernist approach underlie muchof the nature of development in methodology, thinking, institutions,and behavior in the Muslim world throughout its history. They arefound to pervade more intensively, I will argue here, as the consequenceof a taqlid of modernism among Islamic thinkers. I will thenargue that this debility has arisen not because of a comparativemodem scientific investigation, but due to a failure to fathom theuniqueness of a truly Qur'anic epistemological inquiry in the understandingof the nature of the Islamic socioscientific worldview ...

Qualifier la qualité des données localisées numériques des réseaux d’eau et d’assainissement

2019 ◽  
Vol 11 ◽  
pp. 51-64
Author(s):  
M. LE MOAL
Keyword(s):  
A Priori ◽  
A Posteriori ◽  
Systèmes D’Information Géographique ◽  
Systèmes D’Information

Les systèmes d’information géographique (SIG) sont devenus incontournables dans la gestion des réseaux d’eau et d’assainissement et leur efficacité repose en très grande partie sur la qualité des données exploitées. Parallèlement, les évolutions réglementaires et les pratiques des utilisateurs augmentant notamment les échanges d’informations renforcent le rôle central des données et de leur qualité. Si la plupart des solutions SIG du marché disposent de fonctions dédiées à la qualification de la qualité des données, elles procèdent de la traduction préalable de spécifications des données en règles informatiques avant de procéder aux tests qualitatifs. Cette approche chronophage requiert des compétences métier. Pour éviter ces contraintes, Axes Conseil a élaboré un procédé de contrôle des données SIG rapide et accessible à des acteurs métier de l’eau et de l’assainissement. Plutôt qu’une lourde approche de modélisation a priori, le principe est de générer un ensemble d’indicateurs explicites facilement exploitables a posteriori par les acteurs du métier. Cette approche offre une grande souplesse d’analyse et ne nécessite pas de compétences informatiques avancées.

Kant’s ‘Transcendental Deduction’

2018 ◽  
Author(s):  
Barry Stroud
Keyword(s):  
A Priori ◽  
Human Mind ◽  
Critical Assessment ◽  
Structural Description ◽  
A Posteriori ◽  
Human Knowledge ◽  
Transcendental Deduction ◽  
The World ◽  
Empirical Realism

This chapter presents a straightforward structural description of Immanuel Kant’s conception of what the transcendental deduction is supposed to do, and how it is supposed to do it. The ‘deduction’ Kant thinks is needed for understanding the human mind would establish and explain our ‘right’ or ‘entitlement’ to something we seem to possess and employ in ‘the highly complicated web of human knowledge’. This is: experience, concepts, and principles. The chapter explains the point and strategy of the ‘deduction’ as Kant understands it, as well as the demanding conditions of its success, without entering into complexities of interpretation or critical assessment of the degree of success actually achieved. It also analyses Kant’s arguments regarding a priori concepts as well as a posteriori knowledge of the world around us, along with his claim that our position in the world must be understood as ‘empirical realism’.

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