This volume is the current 42-nd thematic issue of the Riga Technical University (RTU)
collection of scientific articles "Boundary Field Problems and Computer Simulation"
in series "Computer Science". The collection continues (since 1999, with slightly
changed title) the lasting international series "Boundary Field Problems and Computers",
issued by RTU since 1966.
Scientific papers regarding simulation results and methodics of model formulation in
hydrogeology, electrodynamics, hydrodynamics, ecology, optical waveguides, signal
processing, and insurance models.
The volume may be of importance to specialists and students interested in computer
simulation of various environmental phenomena.
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(C) Riga Technical University, 2000
Editorial Board*):
A.Spalvins, Dr.sc.ing., RTU - Editor-in Chief
J.Bleiers, Dr.sc.ing., RTU
J.Merkuryev, Dr.hab.ing., RTU
P.Greber, Dr.hab.ing., Dresden Institute of Technology
R.Thunvik, Dr.hab.ing., Royal Institute of Technology (Stockholm)
A.Majewski, Dr.hab.ing., Warsaw University of Technology
R.Janbickis, M.sc.ing., RTU - Secretary
*) Address:
Riga Technical University,
Environment Modelling Centre
1 Meza Street, Riga, LV-1048, Latvia
Phone: +371 7089511; Fax: +371 7820094
E-mail: emc@egle.cs.rtu.lv
URL: http://www.rtu.lv/www_emc/emc_home.htm
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Contents
- Sujecki S.:
BEAM PROPOGATION IN NON-LINEAR TAPERED CO-ORDINATE SYSTEM (Page 5)
Abstract (HTML) | Full Text (PDF; 205KB)
- Solnik W. and Z. Zajda:
AUTOMATION OF OXYGENATION PROCESS IN BIOLOGICAL TREATMENT PLANTS (12)
Abstract (HTML) | Full Text (PDF; 202KB)
- Gregorauskas M., A. Klimas and A. Bendoraitis:
A MODEL OF OIL WATER DISPOSAL INTO HETEROGENEOUS AQUIFER (18)
Abstract (HTML) | Full Text (PDF; 198KB) | Figure 1 (ZIP(cdr); 122KB")
- Spalvins A. and R. Janbickis:
MISFORTUNES OF ZONE SCHEME APPLIED FOR STORING HYDROGEOLOGICAL DATA (28)
Abstract (HTML) | Full Text (PDF; 185KB)
- Spalvins A., J. Slangens and R. Janbickis:
BOUNDARY SHELLS OF HYDROGEOLOGICAL MODELS AS INTERPOLATION DEVICES (32)
Abstract (HTML) | Full Text (PDF; 175KB)
- Slangens J. and A. Spalvins:
CREATING RELIABLE PROGRAM FOR PREPARING LINE DATA OF HYDROGEOLOGICAL
MODELS (35)
Abstract (HTML) | Full Text (PDF; 188KB) | Figure 1 (PDF; 0.99MB)
- Lace I. and A. Spalvins:
INCORPORATING GEOLOGICAL SECTIONS IN HYDROGEOLOGICAL MODELS DATA (41)
Abstract (HTML) | Full Text (PDF; 178KB) | Figure 1 (PDF; 589KB)
- Spalvins A.:
LANDSCAPE ELEVATION MAP AS RELIABLE BOUNDARY CONDITION FOR
HYDROGELOGICAL MODELS (47)
Abstract (HTML) | Full Text (PDF; 184KB)
- Spalvins A., J. Slangens, R. Janbickis, I. Lace, E. Gosk and L. Loukiantchikova:
NEW SIMULATION TECHNOLOGIES APPLIED FOR CREATING HYDROGEOLOGICAL
MODEL OF NOGINSK DISTRICT, RUSSIA (51)
Abstract (HTML) | Full Text (PDF; 185KB) | Figure 1 (PDF; 2.65 MB)
- Antimirov M. and I. Dzenite:
EVALUTION OF SOME EDDY CURRENT TESTING PROBLEMS IN CLOSED FORM
(58)
Abstract (HTML)
- Kolyshkin A. and I. Volodko:
ON THE STABILITY OF VELOCITY WITH REVERSE FLOW IN A PIPE
(69)
Abstract (HTML)
- Matvejevs A.:
INSURANCE MODELS OF PENSION BENEFITS (74)
Abstract (HTML)
- Bleiers J. and J. Lavendels:
SUPPORT OF REAL TIME TASKS IN THE SIGNAL PROCESSING ENVIRONMENT
OF TELECOMMUNICATION SYSTEM (79) (in Latvian)
Abstract (HTML) | Full Text (PDF; 197KB)
- Buikis M. and G. Burov:
TOPOLOGICAL - ASSOCIATIVE ANALYTICAL MODEL OF FORECASTING OF
DYNAMIC PROCESSES (84)
Abstract (HTML)
- Burov G. and G. Vulfs:
THE ANALYSIS OF ACCURACY OF ASSOCIATIVE ALGORITHM OF IDENTIFICATION ON
A DISCREPANCY OF THE EQUATIONS OF MODEL (94)
Abstract (HTML)
- Ozols A.:
DELAYS OF TRAFFIC FLOW IN REGULATED JUNCTION (104)
Abstract (HTML)
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Abstracts of papers
S. Sujecki
Beam propagation in non-linear tapered co-ordinate system
The School of Electrical & Electronic Eng., The University of Nottingham, Nottingham, UK
ABSTRACT: A beam propagation technique is presented which allows the solution of the wave
equation in the case of a dielectric taper without the necessity of staircasing.
The method consists in application of the non-linear tapered co-ordinate system.
As a result curved boundaries between core and cladding can be modelled exactly.
The results obtained are compared with the ones computed using the standard Beam
Propagation algorithm in the rectangular and tapered co-ordinate system.
In all analysed cases the novel approach: Non-linear Tapered Beam Propagation
Method allows calculating the field distribution and the field overlap at the
end of the structure faster and using less computer memory.
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W.Solnik & Z.Zajda
Automation of oxygenation process in biological treatment plants
Institute of Engineering Cybernetics, Technical University of Wrocùaw, Poland
ABSTRACT: Basic applications of programmable controllers in the sewage aeration
control systems are considered. Configurations of binary control systems with one-
and two-speed blowers as well as systems with PID programmable regulators are presented.
Advantages and disadvantages of these solutions and experiences collected during
utilization of implemented projects are discussed.
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M.Gregorauskas, A.Klimas & A.Bendoraitis
A model of oil water disposal into heterogeneous aquifer
Vilnius Hydrogeology Ltd., Lithuania
t
ABSTRACT: In order to forecast injected oily brine spreading at P2 aquifer, regional
spatial filtration and migration models have been constructed. Trivial calculations
shows that after 0.365 million m3 of oily water is injected during 10 years, it will
spread in the area with a diameter of only 250 m. Further spreading of oily water will
be caused by the processes of advection of disposed brine, its dispersion, as well as
sorption and biodestruction of hydrocarbons. Therefore the modelling shows that the
brine spreading will be very slow - only after several thousand years the "tongues"
of injected oily water can reach the Klaip?da waterworks situated at a distance over 20 km.
However, admixture of brine in P2 water will be in fact inconspicuous.
Concentration of hydrocarbons even within the limits of oil fields will not exceed 0.3 mg/l.
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A. Spalvins & R. Janbickis
Misfortunes of zone scheme applied for storing hydrogeological data
Environment Modelling Centre, Riga Technical University, Latvia
ABSTRACT: Misfortunes of the zone scheme unwisely applied by modelling programs for
storing data of novel hydrogeological models (HM) are analised. Methods for tuning
zone converter modules are described, in order to help modellers to lessen side effects
caused by this scheme.
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A. Spalvins, J. Slangens & R. Janbickis
Boundary shells of hydrogeological models as interpolation devices
Environment Modelling Centre, Riga Technical University, Latvia
ABSTRACT: For complex hydrogeological models (HM) including areas of non-existent
geological structures, it is difficult to specify boundary conditions on the HM shell.
These conditions can be obtained automatically when the shell of HM is used,
as a special interpolation device.
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J. Slangens & A. Spalvins
Creating reliable program for preparing line data of hydrogeological models
Environment Modelling Centre, Riga Technical University, Latvia
ABSTRACT: Line data are the major part of information needed to create hydrogeological
model (HM) by the team of the Environment Modelling Centre (EMC), the Riga Technical
University. The CPR program prepares these data, as the input for interpolation.
This paper describes the updated CRP version of improved reliability.
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I. Lace & A. Spalvins
Incorporating geological sections in hydrogeological models
Environment Modelling Centre, Riga Technical University, Latvia
ABSTRACT: The geological section presents a carrier of verified hydrogeological information.
To incorporate it into a hydrogeological model (HM), the special program has been developed
by the Environment Modelling Centre (EMC) of the Riga Technical University.
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A. Spalvins
Landscape elevation maps as reliable boundary condition for hydrogeological models
Environment Modelling Centre, Riga Technical University, Latvia
ABSTRACT: The team of the Environment Modelling Centre (EMC) of the Riga Technical
University has developed an effective method incorporating the landscape elevation map,
as the boundary condition of the three-dimensional (3D) hydrogeological model (HM).
Due to this handy application, reliability of any HM improves considerably.
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A. Spalvins1, J. Slangens1, R. Janbickis1, I. Lace1, E. Gosk2 & L. Loukiantchikova3
New simulation technologies applied for creating hydrogeological model of Noginsk District, Russia
1 Environment Modelling Centre, Riga Technical University, Latvia
2 Geological Survey of Denmark and Greenland, Denmark
3 All-Russian Research Institute for Hydrogeology and Engineering Geology, Russia
ABSTRACT: Since 1993, the team of the Environment Modelling Centre (EMC) of the Riga
Technical University is being active in the field of developing methodologies and special
software for creating hydrogeological models (HM). In this paper, these tools applied together
with commercial ones are described, on the example of complicated HM created for the Noginsk
District, Russia.
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M.Ya.Antimirov & I.A.Dzenite
Closed form solutions of some eddy current problems
Riga Technical University, Institute of Engineering Mathematics
ABSTRACT: Eddy current testing is widely used for the quality control of electrically
conducting objects, such as metals, alloys and semiconductors. An important application
of eddy current testing is the quality control of spot welding in transportation industry,
including aircraft, ship and automobile. In monograph [Antimirov, 1997] the influence
of uniform and non-uniform conducting mediums with different geometries on the current
source in the form of a coil or a double conducting line is investigated. The expressions
for impedance change characterizing the influence of conducting medium on the source of
current are derived in terms of the integrals and series. In this note the integral for
double line is evaluated in closed form in the case, when a source of current is located
on the surface of conducting half-space, but the integral for a coil is transformed into
simpler form. Furthermore, the simple asymptotic formulae for impedance of arbitrary
situated double line and coil in the limit as frequency tends to infinity, are obtained.
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A.Kolyshkin & I. Volodko
On the stability of velocity profiles with reverse flow in a pipe
Institute of Engineering Mathematics, Riga Technical University, Latvia
ABSTRACT: Hydrodynamic stability of velocity profiles with reverse flow in a pipe with
circular cross-section is studied in the present paper. It is shown that shear flow
formed by a cylindrical fluid core moving with a constant velocity in one direction and
a surrounding annulus moving with a constant velocity in the opposite direction is
inviscidly unstable for all wavenumbers. A more realistic case with a parabolic
velocity distribution between the cylindrical core and the surrounding annulus is
shown to be unstable in the interval of small wavenumbers. The width of the interval
depends on the thickness of both fluid layers.
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A. Matvejevs
Insurance models of pension benefits
Institute of Engineering Mathematics, Riga Technical University, Latvia
ABSTRACT: Actuarial method of the tariffs for pension benefits using conditions of
transformation of the insurance contract, changes of the size of the insurance premiums
and/or insurance benefits is considered. Three kinds of the annuity contracts are described:
term insurance of n years, life annuity insurance contract, and life annuity insurance
contract with guaranteed period of benefits. The financial obligations for the accumulation
period, waiting period and benefit period are separately examined. The surrender value
in case of alteration of the contract under the initiative of the participant is considered.
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J. Bleiers1 & J. Lavendels2
Support of real time tasks in the signal processing environment of telecommunication system
1 Environment Modelling Centre, Riga Technical University, Latvia
2 Software Department, Riga Technical University, Latvia
ABSTRACT: A multiprocessor signal processing environment for telecommunication system
where multiple signal processing tasks are supported by every DSP is discussed.
Presented software contains, at first, background part with arbitration of functions
to be executed relatively in parallel. Second part is interrupt service routine that
includes unvarying block of executing algorithms and links for parallel functions.
Each of signal processing tasks must be evaluated for its correspondence to either
the background or the interrupt routine part.
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M. Buikis & G. Burov
Topological - associative analytical model of forecasting of dynamic processes
Institute of Information Technology, Riga Technical University, Latvia
ABSTRACT: The analytical associative algorithm of forecasting of dynamic processes is
considered. The idea of the making recurrent digital filter (Burov, 2000). At a choice
of its parameters the auto regressive model in a combination to the associative approach
is used. The criterion of the coordination of transfer function of the filter with structure
apriori of the given process is used. Before application the adequacy of the predicting
filter apriori to the given experimental data is checked. Besides it is offered on their
basis to estimate expected accuracy of the predicting filter. For this purpose the work
of the filter on the apriori information is simulated. The recurrent iterative procedure
of forecasting is applied and the step-by-step character of increase of an error of the
forecast is estimated. On a concrete example the advantages of the offered approach are
shown in comparison with ARV (Rastrigin and Vulfs, 1997).
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G. Burov & G. Vulfs
The analysis of accuracy of associative algorithm of identification on a discrepancy of
the equations of model
Institute of Information Technology, Riga Technical University, Latvia
ABSTRACT: The accuracy of analytical associative model of identification of dynamic object
is investigated. The approximation of algorithm offered in (Rastrigin and Vulfs, 1997),
results to non-forecasting to change of errors. It is formed under the apriori information
of numerical character written down in the protocol of supervision. Therefore in such
algorithm it is difficult to determine the reason of occurrence of significant ejection
of errors and loss of its serviceability. It is offered to use analytical associative
model, in which the apriori information of mathematical character is used. Such model
can work in conditions of a minimum of the information. It supposes check of adequacy.
This property is used for the analysis of discrepancies of systems of the conditional
equations. Their numerical estimates of discrepancies are used for a filtration of the
information of the observation protocol and adjustment of parameters of algorithm.
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A.Ozols
Delays of traffic flow in regulated junction
Road Traffic Control Laboratory, Riga Technical University, Latvia
ABSTRACT: Because of the increasing automation there are more and more situations in
the junctions of the city streets, when the traffic flow that comes to the junction do
not drive away from it during the time of the current cycle. That, in its turn, leads
to serious losses of national economy. With a presumption that traffic flow is regular,
a graph-analytic method is offered to determine delays of traffic flow in the regulated
junctions. Total delays and also total losses of national economy are determined for real
traffic flow on one of the Riga's streets in one direction, with the worked out method as
the bases of it. The results can be used to substantiate the necessity of improvements in
organizing the traffic.
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