Authors:
Doctor of Science, Professor A.Kolesnikov,
Candidate of Sciences, associate professor
I.Kirikov,
S.Rumovskaya
2


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AH – arterial hypertension;
AP – arterial pressure;
SA DDAH - The System of Automated
Differential Diagnostics of the Arterial
Hypertension
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plurality of alternatives;
the cause-effect relation ‘symptoms — the
diagnosis’ cannot be written on mathematical
language;
depending on presence of a symptom the
probability of concrete disease can raise or be
reduced that is considered in certainty factor;
generally qualitative character of the
symptoms;
in some cases there is absence of the
information about cardiovascular diseases.
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definition of stability and a degree of the AP raising;
an exception of a symptomatic arterial hypertension
or identification of its form;
definition of the common cardiovascular risk;
revealing of other risk factors of the cardiovascular
diseases and clinical states;
definition for the patient’s risk group;
diagnostics of defeats of the target organs.
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Examined
Measurement of
blood pressure
Tonometer
A doctor
AP data
(NF)
A patient
Questioning
patient
The
start of
Confirmation
check- of the AP raising
up
Data
input
Control over 1
or 2 years
The beginning
of the diagnosing
Symptoms, his
deseases and in
his family
(particularly SF)
History
taking
Anamnesis
data input
Processing AP data (the
results in SF)
Examination,
palpation
of the
patient
Lab
Physical
examination
Input of
the results
of physical
exam
Blood and urine
tests - NF
echo, ECG, X-ray
picture – SF and NF
The results
(particularly
SF)
Guidelines under
analyses (SF)
Processing of the input data
(the results in SF)
Laboratory
examination
Data
input
Processing (the
results in SF)
The final
diagnosis (SF)
Systolic AH
DDAH
Expert SAknowledge
Signs. SF - symbol format, NF – numerical format, AP – arterial pressure, ECG – electrocardiogram
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questions for a history taken and analyzing
of the medical report;
 questions for fixing the results of doctor’s
objective
examination
(for
more
information);
 questions for fixing the results of special
diagnostic procedures, laboratory and tool
methods (a necessity in them exists there for
an exact ascertainment or diagnosis
confirmation)

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






Unification of the methods for an arterial hypertension and demonstrating a
complete disease picture.
The necessity of the efficiency of decision-making, training students to make
diagnoses and working off their skills of the definition of what data is necessary for
making diagnosis, and searching for this data (as automated system proves in detail
its outputs).
The development of the knowledge field and of the doctor-cardiologist’s base of the
facts.
The development of the knowledge base.
The development of the mechanism of an explanation of the diagnosis made by the
system.
The development of the system laboratory prototype.
The system testing.
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Field of knowledge — conditional informal description of the main
concepts and interrelations between concepts of the subject domain,
revealed from the expert knowledge system, in the form of the diagram, the
table or the professional text. The field of knowledge represents the model
of problem domain knowledge.
As the elementary pragmatical approach to a creation of the field of
knowledge the following sequence of operations was used:
definition input and output data;
compilation of the terms dictionary and sets of key concepts;
revealing links between concepts;
construction of a pyramid of knowledge — a scale of ranks of concepts;
definition of relations (as well as relations between concepts inside each
level of a pyramid and between concepts of different levels).
The degree of the knowledge field is: concepts – 415, relations — 15.
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Hierarchy of the base of facts in the system
Slots of Anamnez, Fizikal, Labobsled and AD contain input
data for solving of the task of the diagnosing arterial
hypertension.
Global
NamePass
Menu8
DDE
Image
Objects of the subclass Diagnoz — are the component parts of
the diagnosis generating as the result of examing:
Giperton (a stage of the hypertension);
Risk (general cardiovascular risk);
UrovenAD (the level of the AP);
Recommend (recommends about the laboratory examination
and the necessity of the following examination);
VtorAG (the secondary hypertension).
KWindow
Root
Pacient
Objects
Class
Diagnoz
Anamnez
Fizikal
Labobsled
AD
Giperton
Risk
UrovenAD
Recommend
VtorAG
FR
POM
ASK
The size of the system base of the facts makes
about 350 variables (pairs ‘object: slot’).
Objects of the subclass VtorAG — are the diseases found of the
patient:
FR (risk factors);
POM (lesion of the target organs);
ASK (associative clinical state).
Each object of the subclasses Diagnoz и VtorAG has also
features, in which slots contain certainty factors of all
components.
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Certainty factor is calculated on the base of Karnap’s confirmation theory of two evaluations: the belief measure
MB(H,E) and disbelief measure MD(H, E).
The belief and disbelief measures are fixed in the terms of prior and conditional probability (1), (2):
1, if P( H )  1;

MB ( H , E )   max  P( H | E ), P( H )   P( H )
, if not.

max
1,
0

P
(
H
)



1, if P( H )  0;

MD( H , E )   min  P( H | E ), P( H )   P( H )
, if not.

min
1,
0

P
(
H
)



(1)
The function point out the growing up
of the belief measure to the hypothesis
H, if the fact Е have taken place.
(2)
The function point out the growing up
of the disbelief measure to the
hypothesis H, if the fact Е have taken
place.
where:
p(H) – prior probability, that hypothesis H is true;
p(H|E) – conditional probability, that hypothesis H is true at the fact E having taken place;
MB  H , E   0;1 and MD  H , E   0;1.
The certainty factor, CF(H,E), is calculated in the system, proceeding from values of belief and disbelief
measures (3):
CF ( H , E )  MB( H , E )  MD( H , E )
(3)
And is located between -1 and +1, defining the belief measure to the hypothesis H.
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The most general view production rule:
(i); Q; P; A  B; N ,
(4)
where:
i — the identifier of the production;
Q — the application area of rule, namely ‘islands of knowledge’;
A→B — a production kernel - if the logical expression accepts value TRUE, then conclusion becomes TRUE, too, that is
mean probability of symbol conversion, defined by a kernel, or some operation;
P — a condition of applicability of a production kernel, often expressed by a predicate. A condition of applicability and
premis of the production’s kernel A are written as one expression and, essentially, make the symbol pattern in our automated
system;
N — a postcondition executable only after implementation of a kernel of production and represents our changes in a chain of
reasoning which should be made in the knowledge base, is not used in our automated system.
(confirAG 2); Rulelist1;
' SAP  120 AND SAP  130 AND DAP  80 AND DAP  85’  god 2  TRUE AND Unorm  TRUE;
Re ccom  'The control over two years!’.
‘Islands of knowledge’
Rulelist1
RulelistA
RulelistF
RulelistL
RulelistOG
RulelistReas
RulelistKD
Rulelist1 contains rules analyzing AP information.
RulelistA contains rules for analyzing the information, gathered on the stage History taking.
RulelistF contains rules for analyzing the information, gathered on the stage of the physical examination.
RulelistL contains rules for analyzing the information, gathered on the stage of the laboratory examination.
RulelistOG contains rules for definition of the cardiovascular degree and the stage of hypertension.
RulelistReas contains rules for definition of the symptomatic AH.
RulelistKD contains rules for estimation of the diagnosis certainty factor.
(5)
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Subgraph of the graph of an island of knowledge ‘Analising AP information’
god2= TRUE
OR
OR
AND
SAP>120
Unorm= TRUE
SAP<=130
AND
DAP>80
DAP><=85
Signs. node of graph
— node of the type AND (conjunction of the facts signed by arc); SAP — systolic AP, DAP
— diastolic AP, god2 — checking the AP in two years, Unorm – normal level of the SH.
Informatively this is the rule: ‘If 120 < ‘systolic pressure’ <130 and 80 < ‘diastolic pressure’ <85 then ‘level of arterial
hypertension’ is normal and it is also recommended to check the arterial pressure in two years’.
In the SA DDAH:
the reasoning strategy is forward chain;
reasoning during the solution of the task of diagnosing arterial hypertension — are ‘wide and deep’;
strategies for the resolution of rule conflicts — ‘a selective estimation’ .
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A laboratory prototype — is a system solving all demanded problems, but not steady in operation and not completely
checked up. The laboratory prototype includes two more important units — user interface and the mechanism of
explanation results of a solution task.
The user interface consists of eight main windows:
confirmation of lifting the arterial pressure (windows for information input)
information input during the history taking
information input during the physical examination
information input during the laboratory examination
input of results of the analysis of blood
input of results of the analysis of urine)
one output window of results and their correction (results of examination of the patient)
one window for operation with library of reports and patient cards.
Resume by the testing of the system:
By the results of testing the island of knowledge ‘the information analysis on physical examinations’ and guidelines
to laboratory inspection have been corrected. Also the information in remarks of rules has been enlarged for rising a
transparency of the diagnosis and improvement of the mechanism of an explanation.
On termination of testing the expert has given the conclusion about the quality of the automated system. The opinion
of the doctor-expert is the following: ‘the system is ready to experimental application for students trainings, the
interface is clear; the high performance of reception of the results (information processing does not exceed 0,5
seconds) and their validity was pleasant’.
On the basis of the received results has been concluded that the system gives sufficient and detailed diagnosis at the
patient’s examination with suspicion on an arterial hypertension.