This volume is the current 44-th 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, signal processing, and system
identification.
The volume may be of importance to specialists and students interested in computer
simulation of various environmental phenomena.
|
(C) Riga Technical University, 2002
Editorial Board*):
A.Spalvins, Dr.sc.ing., RTU - Editor-in Chief
A.Kolishkin, Dr.math., RTU
M.Antimirov, Dr.hab.phys., 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 7089531
E-mail: emc@egle.cs.rtu.lv
URL: http://www.rtu.lv/www_emc/
|
Return to Top
Contents
- Otremba Z.:
SIMULATION OF THE CONTRAST OF THE SEA AREAS POLLUTED BY OIL SPILLED
ON THE SURFACE AND DISPERSED IN THE WATER COLUMN (Page:6)
Abstract (HTML) | Full Text (PDF; 341KB)
- Herb P., P.-W. Graeber and O. Kemmesies:
COMBESICK - A COMPUTER-BASED DECISION SUPPORT SYSTEM
FOR SEEPAGE PROGNOSIS (13)
Abstract (HTML) | Full Text (PDF; 1174KB)
- Spalvins A., Slangens J., Janbickis R., Lace I. and P. Hein:
MODELLING OF REMEDITATION TOOLS FOR THE CONTAMINATED
BERNAU PLACE, GERMANY (20)
Abstract (HTML)
| Full Text (PDF; 171KB)
| Fig.1 (PDF; 154KB)
| Fig.2 (PDF; 117KB)
- Spalvins A., Slangens J., Janbickis R. and I. Lace:
NOVEL INTERPOLATION TOOLS FOR CREATING HYDROGEOLOGICAL
MODELS (29)
Abstract (HTML) | Full Text (PDF; 818KB)
- Ghidaoui M. S. and A. A. Kolyshkin:
UNSTEADY LAMINAR FLOW IN A PIPE (36)
Abstract (HTML)
- Volodko I.:
USTEADY VISCOUS FLOW IN AN ANNULUS (43)
Abstract (HTML)
- Antimirov M. Ya. and I. A. Dzenite:
NEW FORMULA FOR IMPEDANCE CHANGE IN THREE-DIMENSION CASE (48)
Abstract (HTML)
- Antimirov M. Ya. and I. A. Dzenite:
EXACT SOLUTION FOR THE PROBLEM ON IMPEDANCE CHANGE OF A RECTANGULAR
FRAME WITH CURRENT INSIDE A CYLINDRICAL TUBE (54)
Abstract (HTML)
- Bleiers J., Lavendels J., Latisheva L. and P. Misans:
USING OF THE SAMPLE BUFFERS IN THE HARD REAL TIME SIGNAL PROCESSING
ENVIRONMENT OF TELECOMMUNICATION SYSTEM (63)
Abstract (HTML)
- Bleiers J., Lavendels J., Kalejs A. and N. Veselis:
CT-BUS ORIENTED TESTING AND DEBUGGING FOR DSP MULTIPROCESSOR
TELECOMMUNICATION BOARD
(69)
Abstract (HTML)
- Burovs G.:
THE STRUCTURAL DISBALANCEMENT OF REGRESSION MODELS OF DYNAMIC
OBJECTS IDENTIFICATION
(73)
Abstract (HTML)
- Burovs G. and K. Andersons:
THE OPERATIVE ESTIMATION OF COMPUTING STABILITY OF SIGNALS DISCRETE
PROCESSING ALGORITHMS (83)
Abstract (HTML)
- Andersons K.:
USE OF RECURRENT RELATIONS IN DYNAMIC CONTROL MODELS
OF ANALOG OBJECTS (91)
Abstract (HTML)
- Vizulis P.:
DIFFERENCE CORRELATION MODELS OF THE CONTROL
OF ANALOG DYNAMIC OBJECTS (100)
Abstract (HTML)
- Burovs G.:
ABOUT DRAWBACKS OF THE VULF - RASTRIGIN "ASSOCIATIVE ALGORITHM" (108)
Abstract (HTML)
Return to Top
Abstracts of papers
Otremba Z.
Simulation of the contrast of the sea areas polluted by oil spilled
on the surface and dispersed in the water column.
This paper presents the results of the modeling of reflectance function of the sea
polluted by oil that appears as film and as suspensions of droplets. The film thickness
is 5 mm, which relates to 5 cm3 of oil per 1 m2 of sea area. The same amounts of oil in
the water column in relation to the sea unit area as for film were applied for various
thicknesses of sea-layer polluted by dispersed oil. The calculations were made by the
simulation of the life of a big number of photons falling on the sea surface (Monte
Carlo method). Non-monotonic dependence of the thickness of the oil 'cloud' in the
bulk of sea on the reflectance was detected.
Return to Contents
Herb P., Graeber P.-W., Kemmesies O.
COMBESICK - A computer-based decision support system for seepage prognosis.
Soil and groundwater are important natural resources. Due to increasing demand for soil and
groundwater, their limited capacity, and the difficulties of remediating these resources
once contaminated, their protection has become increasingly important. As a result, in
1999 the German legislator introduced the so-called Bundes-Bodenschutzgesetz (BBSchG) -
a law regulating the protection and remediation of soil in Germany. According to the
BBSchG a seepage prognosis has to be conducted if contaminant concentrations in the
soil exceed values specified in the BBSchG. The purpose of the seepage prognosis is
to determine potential groundwater contamination originating from surfecial contaminated sites.
Computer-based simulation of contaminant transport in the unsaturated zone is an indispensable,
cost-effective method of conducting a seepage prognosis. We suggest a decision support system
for seepage prognosis (COMBESICK) which will be easy to use, widely available, and less
error-prone than previous seepage modeling software.
Return to Contents
Spalvins A., Slangens J., Janbickis R., Lace I., Hein P.
Modelling of remeditation tools for the contaminated Bernau place, Germany.
Modelling of Remeditation Tools for the Contaminated Bernau place, Germany
The Bernau place (located ~ 50 km east of Berlin) is heavily polluted with trichlorethene (TCE).
To help in solving the remedy problem of the place, a system of hydrogeological models has been
developed by the Environment Modelling Centre of the Riga Technical University. The paper
summarizes information by modeling TCE - transport if various remediation tools (drains,
reactive walls, wells) are applied for cleaning the place. Advantages and drawbacks of
these tools are explained if they are used for long term (10 - 20 years) remediation of
the soil and groundwater of the Bernau place.
Return to Contents
Spalvins A., Slangens J., Janbickis R., Lace I.
Novel interpolation tools for creating
hydrogeological models.
The quality of a hydrogeological model (HM) depends not only on credibility of initial data,
bat also upon interpolation technologies applied to create HM. The Environment Modelling Centre
of the Riga Technical University has developed a system of reliable interpolation tools.
It contains the following interdependent items: the geological data interpolation (GDI)
program for obtaining principal elements of the HM system; line data for GDI is prepared
by so called crosspoint (CRP) program; the special program has been developed for
interpolation of input and output data for sites, not matching the grid nodes of HM;
the shell of the HM grid acts as an interpolator for boundary conditions. In the paper,
theoretical ideas implemented into these tools above are explained.
Return to Contents
Ghidaoui M.S. , Kolyshkin. A.A.
Unsteady laminar flow in a pipe.
The problem of unsteady viscous incompressible flow in an infinitely long pipe
of a circular cross section is considered in the paper. The unsteady flow is
caused by the change of the velocity and pressure in the fluid. The fluid flux
through the cross section of the channel decreases to zero during a finite time interval.
It is assumed that the flux change is described by a linear function of time. Such a model
corresponds to the real case of fluid flow in a pipeline. It is shown that the flow has
minor changes in the central part of the channel while sudden changes of the velocity and
pressure occur in the boundary layers near the wall of the pipe. An analytical solution
of the problem is found under the assumption that the velocity vector has only one nonzero
longitudinal component which is a function of radial coordinate and time. The solution is
found by the method of the Laplace transform. The inverse Laplace transform is found by
means of the residue theorem. The solution is found in the form of a series containing
Bessel functions. The velocity distribution is calculated as a function of time and the
parameter which characterizes the rate at which the flux reduces to zero. The results
are compared with the solution of a similar problem in the case where the fluid flux is
set to zero instantaneously.
Return to Contents
Volodko I.
Usteady viscous flow in an annulus.
Unsteady flow of a viscous incompressible fluid in the region between two infinitely
long concentric cylinders is considered in the paper. The flow unsteadiness is caused
by a sudden change of the velocity and pressure in the fluid. The fluid flux through
the cross section of the channel is set to zero instantaneously. As a result a fully
developed Poiseuille flow is modified and boundary layers start to develop near the
walls of the channel. Analytical solution of the problem is found under thecondition
that the velocity vector has only one nonzero longitudinal component which is a function
of radial coordinate and time. The Laplace transform is used to solve the problem.
The inverse Laplace transform is found by means of the residue theorem. The solution
is found in the form containing Bessel functions and is suitbale for calculations.
Return to Contents
Antimirov M. Ya., Dzenite I. A.
New formula for impedance change in three-dimension case.
New formula to the impedance change for the case of a flaw of an arbitrary form located
in a conducting half-space and of the closed emitter of an arbitrary form located in the
horizontal plane above the conducting half-space, is obtained. The Green's formula is used
in contrast to previous authors. It is noted that similiar formula for impedance obtained
by previous authors using the Lorentz theorem is not correct in common case.
Return to Contents
Antimirov M. Ya., Dzenite I. A.
Exact solution for the problem on impedance change of a rectangular
frame with current inside a cylindrical tube.
Exact solution of the problem on impedance change of a rectangular frame with current inside a
cylindrical tube is obtained in the form of series that are quite appropriate for computer calculations.
The solution can be used for the wall thickness control in the case of non-concentric wall surfaces.
Return to Contents
Bleiers J., Lavendels J., Latisheva E., Misans P.
Using of the sample buffers in the hard real
time signal processing environment of telecommunication system.
Architecture for multiprocessor signal processing environment for telecommunications system is
discussed in this paper. Using of the sample buffers may increase the promotion of signal
processing system. With one execution of the each signal processing routine the large amount
of signal samples are processed. From the other side using of the signal buffer produce the
delay time for each signal sample processing The admissible delay time of sample processing
is determined for each kind of signal process.The target of this paper is performing detection
of the decay time for multiple signal processing system with sample buffers.The obtained
results allows to optimize signal processing software in multiple signal processing system.
Return to Contents
Bleiers J., Lavendelis J., Kalejs A., Veselis N.
CT-bus oriented testing and debugging for DSP
multiprocessor telecommunication board.
Some aspects of development of computer telephony (CT) bus based digital signal multiprocessor
are described in this paper. Various CT-bus standards provide a time-multiplexed serial data
flow between CT-bus devices and require special development and testing tools. Wide known
debugging tools include the software simulators, debugging modules and emulators, JTAG boundary
scan ports as well as using of particular CT-bus design tools.
As a way for testing and monitoring the bus hardware and software, using of CT-bus tester and
signal processors with CT-bus compatible peripherals is proposed and discussed. The tester is
a multifunctional device that can produce various test signals for bus equipment and analyze
data received from the bus. Analysis of data can be executed due to internal or external hardware.
Effective mode is to generate a random data flow by CT-bus tester and analyze a bit error rate in
the received data flow.
The loop-back based testing configuration includes a CT-bus oriented tester, multi-DSP environment,
time-slot interchanger and external peripheral modules. External modules based on the ADC and DAC
converters support a loop-back between signal processors. The described configuration is used for
multiprocessor signal processing board designed for telecommunication needs.
Return to Contents
Burovs G.
The structural disbalancement of regression models of dynamic objects identification.
The methodical errors of regressive model of identification of dynamic objects are investigated.
The errors are determined as disbalancement of model. It is defined by mismatch exogenous and
auto regressive parts. First is connected to occurrence of errors of signals quantization.
Second is connected to discrepancy about model and structure of an output signal.
The conclusion about expediency of application in test modes on different intervals of an
output signal of local regressive models is made.
Return to Contents
Burovs G., Andersons K.
The operative estimation of computing stability of signals discrete
processing algorithms.
The accuracy of identification is defined by computing stability of algorithms, which depends
on a processable signals dynamics. Therefore it is offered to use algorithm computing stability
parameters for a filtration of the information acting in identification model. Classical methods,
connected with an estimation of conditionality numbers unsufficiently high-speed. They can not work
in a real time scale. For this purpose the method based on an estimate of norms of signals differences
is offered. Is shown, that output signal differences can be used in identification model.
Return to Contents
Andersons K.
Use of recurrent relations in dynamic control models of analog objects.
The task of the control of analog dynamic object with application of the digital imitative
programs is considered. They are used for formation of transfer functions of its discrete models.
With the help them the possible operational condition of object are reflected. The control is
conducted on mismatches of the received parameters estimates and coefficients of model.
Is shown, that the allowable mismatches should pay off in view of the period of signals sample.
The offered method is expedient for applying in test modes of the dynamic control.
Return to Contents
Vizulis P.
Difference correlation models of the control of analog dynamic objects.
The task of diagnosing of analog dynamic object condition is considered on the basis of use of signals
correlation functions. The correlation model of identification is characterized by discrete transfer
function. It allows to apply a method of parametrical identification. The specified approach is
offered for applying in test control mode. In the capacity of input signals the pseudo-casual
binary pulse sequences are used. The advantage is complete indemnification of control methodical errors.
By it the method differs from traditional ways of use of such signals.
Return to Contents
Burovs G.
About drawbacks of the Vulf-Rastrigin "associative algorithm".
Drawbacks of the "associative algorithm ", advertised in Vulf"s and Rastrigin"s papers [1,2]
are considered. The erroneous axiom is accepted that the mapping of diverse information spaces
have universal linear character. Such appendices of the algorithm are offered, where it is
impossible to check up reliability of obtained results. The practical realization of the
algorithm is impossible, because it is based on the inversion of matrixes close to singular ones.
Models for identification of dynamic objects are based to on recurrent relations. Thereby it
leads to results having no real sense.
Return to Contents
Return to Top
|
