Valery Sadovoy, Assistant Professor
Crimea State Medical S. I. Georgievsky
University, Ukraine
Oleg Parmenov, Assistant Professor
Taurida National V.I.Vernadsky University,
Ukraine
Ibrahim Ismailov, Master of Computer Science
Taurida National V.I.Vernadsky University,
Ukraine
Distributed
information system
“Register of myocardial infarction”
The
task was to design distributed information system “Register of myocardial
infarction”. This system is very crucial, because cardiovascular diseases are
common reason of death today [1]. In order to
provide data processing and statistical analysis, it was necessary to automate
the process of data maintenance. The main customer demands were: a) to provide
multi-user access to a data repository from different regions of the Republic
of Crimea; b) to provide data
processing and data analysis functionality.
As
usual, the property named “distributed” means that the system operates with a
regardless of a user’s location [2], that`s a distributed database is a system
in which all components are located on networked
computers. These computers communicate with another one and coordinate their
actions by passing messages. Another widely used conception of database
management is based on linked network nodes.
There were the following requirements to the
distributed computer system:
1)
To provide multiuser access via the Internet, i.e. the system must be based on
properties of non-concentrated database implementation with Web interaction. An application user doesn't interact right to the
server to provide transitory offline service (without an access to the
Internet) with synchronization in a background;
2)
The system has to support statistical and regression analysis
of stored data.
Thus it was important to solve three technical problems:
1)
to choose web hosting service. We take DigitalOcean service because
of its inexpensive and reliable hosting. Minimal delivered requirements (512 MB
operational memory, 2 cores) are quite acceptable at that period of time.
2)
to choose database management system. The preference was
given to MySQL database system because of its performance and gratuity.
3)
to choose software environment. The Java has an advantage
because of its gratuity.
We propose the synchronization technology between a
local database and server data repository which is grounded on the monitoring
of the database version. This monitoring is implemented on a local nodes and on
the server.
All local copies of database generate unique
identification number– shortly called ID or version number. These ID are stored
on every node after any local database modification. The similar technology of ID
generation is implemented in the server database.
When a single user adds or modifies data in a local
database, the application sends the request to the server for updating
automatically. Procedure of updating server repository works in the same way.
On account of synchronization and personal data protection
requirements, we embed the following software and hardware solutions:
1)
Data
encryption. All data is stored and is sent via Internet in ciphered form with
8-byte DES algorithm encryption;
2)
Data
access security. The data safety is based on principles of enclosed system.
Firstly, data can be obtained and correctly decrypted only by using this
software and not in the other way. Secondly, the password is need for
installing and executing the application on a local computer.
We estimated a functional
stability, survivability and reliability of the system. In accordance to the
requirements of standard ISO/IEC 27001, we carried out comprehensive testing to
ensure reliability such as: software regression testing and performance
optimization, load testing and Denial-of-Service attacks modelling (DOS-attacks
may exhaust the server resources and causes a loss of operability and system
crash).
By tuning-up the
database configuration and hosting service configuration we get steady
stability of application. System stability and data integrity are provided even
in over-load system mode. Testing procedure loads the server component by a
simulation of about 100 virtual users activity.
It has been found that
in load peaks with high-intense transactions the system performance does not
violate. The characteristics of system reaction and system load which obtained
in test mode are shown in the graph.
In this test, the interval between consecutive transactions of an every
of 100 users was about a second. Obviously, the system response time increases
with the number of users, but it’s tending to stabilize at about 50 users. Even
with 100 users loading the response time does not exceed 5 seconds.
The system provides a highly efficient statistical analysis using a
variety of common criteria. We implement prevalent mathematical methods to
provide calculating of Student data reliability criteria, Spearman’s and
Kendall’s correlation ranks and a regression analysis. The diagram presents the
regression analysis results as an example of data processing. Thus the clotting time decreasing has a
direct correlation with high rates of atherogenic (left chart) .
The diagram of risk factor categories - heart rate and cholesterol
level - is shown on the right chart. User application provides two-dimensional
and three-dimensional charts and diagrams with an approximation on squares method
and non-linear multivariable regression which is solved by normal equation.
Main gained results are:
1)
It was designed the system for cardiology hospitals of the
Crimea which works in real-time with Internet access to database repository; it
provides an offline-mode operating also.
2)
It was obtained database and server stability and their high
performance. The system guarantees from unauthorized access.
3)
The software suite also provides data processing and
analyzing. An application user may select on one’s own criteria the method of
data visualization and statistical processing procedure.
We hope that the system increases the efficiency of
diagnostic work and reduces a medical errors chance.
References
[1]. Roger VL, Go AS, Lloyd-Jones DM, et al. (January 2012).
"Executive summary: heart disease and stroke statistics--2012 update: a
report from the American Heart Association". Circulation 125
(1): 188–97
[2]. M. T. Özsu and P. Valduriez, Principles of Distributed Databases
(3rd edition) (2011), Springer