| |
RT&A
2010,
# 1(16) Vol.5
Bożena Babiarz
RELIABILITY ASSESSMENT OF HEAT
SUPPLY SYSTEMS IN THEIR OPERATIONAL PROCESS
This
paper presents an analysis of the operational process
of heat supply system, taking into consideration its
reliability. The specific character of the operation of
heat-supply systems has been considered in this work. In
the process of exploitation of heat-supply systems five
operational states have been distinguished, using as a
criterion the level of indoor temperature decrease in
residential rooms. The method of modelling the
reliability of heat-supply systems is worked out. The
methodology of determining the overall index of
heat-supply system reliability has been presented. The
measure of heat-supply system reliability has been taken
to be as the scale/quantity of inadequate supply of heat
power at a given state. Calculations have been carried
out regarding the changeability of exterior conditions
for one of the groups of customers – residential users.
On the basis of the operational data for the heat supply
system with two heat sources, shortfalls of heat power
and the probability of their occurrence have been
calculated as an application of this methodology.
R. V. Kakubava
Multi-line Markov closed queuing
system for two maintenance operations
In the
given paper multi-component standby system with
renewable elements is considered. For it multi-line
closed Markov queuing model for two maintenance
operations – replacements and renewals, is constructed
and investigated. In this model the numbers of main
elements as well as standby ones, also the numbers of
replacement units as wall as renewal ones are
arbitrary. An economic criterion for dependability
planning (structural control) of considered system is
introduced, the optimization problem is stated and
partially investigated.
R. Lisi, M. F. Milazzo, G. Maschio
RISK ASSESSMENT OF EXPLOSIVE
ATMOSPHERES IN WORKPLACES
The
application of the Directive 99/92/EC deals with the
safety and health protection of workers potentially
exposed to explosive atmospheres and requires the
assessment of explosion risks. These can arise by the
release of inflammable substances typical of industries
classified as major hazards, but they often may be
generated in other industries where inflammable
materials are handled. Risk assessment of explosive
atmospheres is required in both cases, for this purpose,
in this article a quantitative approach has been
proposed. The paper describes the main aspects of the
methodology, based on a probabilistic risk assessment,
and finally its application to a case-study.
R. Dubčáková, P. Praks
Statistical modelling of indoor
radon concentration using meteorological parameters
The
radon volume activity in buildings is generally time
variable. Its variability is caused by many natural and
man-made factors. An example of these factors includes
meteorological parameters, soil properties,
characteristics of the building construction, properties
of water used in the building and also the behavior of
inhabitants. These factors can influence each other and
also they are related with the exposition of
inhabitants. This article reports a continual indoor
radon monitoring and a statistical evaluation of
a dataset obtained by the 18 days-long measuring in a
house located in the Czech Republic. The contributions
of carefully selected meteorological parameters and
human influences were also observed. Results of the
observation were divided into two parts (inhabited,
uninhabited) and analyzed in relation with the indoor
radon concentration. The multiplied linear regression
was applied to model obtained datasets. Results of time
series analyses of the continual indoor radon
concentration and the meteorological monitoring are
presented and discussed as well.
G.Tsitsiashvili, A. Losev
CALCULATION OF CONNECTIVITY
PROBABILITY IN RECURSIVELY DEFINED RANDOM NETWORKS
In this
paper a problem of a construction of new and practically
interesting classes of recursively defined networks,
including internet type networks, with sufficiently fast
algorithms of calculation of connectivity probability is
considered. For this aim recursive and asymptotic
formulas of connectivity probability calculation are
constructed. Asymptotic formulas are based on
assumptions that all network arcs are low reliable or
there are high reliable and low reliable arcs in
considered network. For example in radial-circle scheme
radial arcs may be high reliable and circle arcs – low
reliable.
Yakov Genis
RELIABILITY ASSESSMENT OF SYSTEMS
WITH PERIODIC MAINTENANCE UNDER RARE FAILURES OF ITS
ELEMENTS
There is
investigated à model of a system with the highly
reliable elements, where the periods of functioning are
changed by the periods of maintenance. The system must
be operational only in the periods of functioning
although the restoration in these periods is not
provided. The system is completely restored in the
nearest period of maintenance. Since the elements of
system are highly reliable, the reserve of system is
rarely exhausted during each period of functioning.
Therefore it is possible to use the results, obtained
for the systems with fast restoration, for the
reliability assessment of system, which is not
restorable in the periods of the functioning. The
estimations of indices of failure-free performance and
maintainability of such systems are obtained.
M. Zajac, D. Valis
FUNDAMENTAL RISK ASSESSMENT IN
EXAMPLE OF TRANSSHIPMENT SYSTEM
The
paper represents discussion about risk assessment for
transhipment system in reduces data condition. As a
particular example transhipment system is presented.
Article can be treated as first estimation. Future work
and objectives are characterized in the end.
G.Sh. Tsitsiashvili
ASYMPTOTIC ANALYSIS OF LATTICE
RELIABILITY
Asymptotic formulas for connection probabilities in a
rectangular lattice with identical and independent arcs
are obtained.. For a small number of columns these
probabilities may be calculated by the transfer matrices
method. But if the number of columns increases then a
calculation complexity increases significantly. A
suggested asymptotic method allows to make calculations
using a sufficiently simple geometric approach in a
general case.
Al. Isaic-Maniu, I. M. Dragan
THE RISK OF OPERATIONAL INCIDENTS
IN BANKING INSTITUTIONS
Banking-financial institutions are organizations which
might be included in the category of complex systems.
Consequently, they can be applied after adaptation and
particularization, in the general description and
assessment methods of the technical or organizational
systems. The banking-financial system faces constrains
regarding the functioning continuity. Interruptions in
continuity as well as operational incidents represent
risks which can lead to the interruption of financial
flows generation and obviously of profit. Banking
incidents include from false banknote, cloned cards,
informatics attacks, false identity cards to ATM
attacks. The functioning of banking institutions in an
incident-free environment generates concern from both
risk assessment and forecasting points of view.
|
