Sessions XIV and XV of the XX^th Wilga Symposium were devoted to the Pi of the Sky project, aimed at massive automated photometry of celestial objects. The original goal of the project was early detection of optical afterglows from gamma-ray bursts, but it soon expanded into a general survey of all kinds of fast astronomical phenomena occurring above a certain limiting magnitude. The idea stems from two ingenious suggestions by late Professor Bohdan Paczynski: that gamma bursts are extragalactic phenomena (therefore, they are extremely energetic and equally extremely interesting), and that the classical observational approach (big telescopes, long exposures, small areas of the sky) should be supplemented by "massive photometry", with many small telescopes quickly repeating observations of large areas of the sky (in a desirable limit - of the whole sky). Paczynski was not personally involved in Pi of the Sky, but as the spiritual father of the project, and as one of the greatest contemporary astrophysicists, he certainly deserves to be remembered here.

A robotic system for continuous observation of a night sky is proposed. The "Full Pi of the Sky" system will consist of 32 CCD cameras and 8 motorized parallaactic mounts. The location of a future observation site requires full remote control and autonomous on-line and off-line data analysis. Inorder to test scalability of the sytem and to develop optimal control and analysis algorithms a full, real-time jardware simulation will be employed. The concept of the "Full Pi of the Sky" architecture and some aspects of its software emulation are discussed in this paper.

Based on the data from the "Pi of the Sky" project a catalog of variable stars with a period from 0.1 to 10 days was prepared. We analyzed data collected during the period of two years (2004 and 2005) and we identified 725 variables stars. Most of the stars in our catalog are classified as eclipsing binaries - 464 (about 64%) while the number of pulsating stars is 125 (about 17%). Our classification was based on the shape of the light curve, as in the GCVS catalog. However, some stars from the GCVS catalog were classified differently in our catalog. We found periods for 15 stars included in GCVS catalog as stars with yet unknown period and absent in the ASAS catalog.

The main aim of the "Pi of the Sky" experiment is to search for optical flashes associated with the gamma ray bursts. The detector also allows us to study other kinds of short timescale astrophysical phenomena. During everyday observations "Pi of the Sky" detector collects many measurements of interesting objects like blazars, quasars, variable stars etc. It is very important to make this data available to other experiments as fast as possible. Dedicated WWW interface connected with the "Pi of the Sky" database in Chile was created to provide on-line access to selected objects. The interface allows quick and easy accesses to the "Pi of the Sky" data right after all measurements processes are finished.

The Pi of the Sky experiment, located at Las Campanas Observatory in Chile, searches for rapidly changing optical objects such as optical counterparts of Gamma Ray Bursts. The system consists of two CCD cameras placed on parallactic mount and operated by a PC equipped with dedicated software. The data acquired is reduced and essentially only the brightness of stars is stored in the database. A web interface for the star databases offers easy and quick access to the experiment's data and to other star catalogs that are also stored in our databases.

The Pi of the Sky experiment searches for optical flashes of astronomical origin. Every night thousands of pictures of the sky (frames) are taken with CCD cameras. This article describes an algorithm designed for automatic estimation the quality of taken frames.

"Pi of the Sky" is a robotic telescope aimed for monitoring of large part of the sky and looking for Gamma Ray Bursts with CCD cameras. One of the main parts of the project are: the mechanism pointing the cameras to given area of a celestial sphere. We present the final design of the new mount with four cameras which is now under tests.

The hardware emulator of the CCD sensor is described. It was initially designed for 'Pi of the Sky' project purposes, to speed-up the post-assembling test, but it can be easily adapted to other CCD-related hardware debugging needs. The 'Pi of the Sky' experiment searches for optical counterparts of gamma ray bursts from surface of the Earth. The CCD emulator accelerates the development procedure and simplifies post-assembly tests. Since CCD sensor is very fragile device, such emulator reduces risk connected with one handling during the final camera electronics tests and debugging.

The concept of the Altera Nios II embedded processor implementation inside Field Programmable Gate Array (FPGA) of the CCD camera for the "Pi of the Sky" experiment is presented. The digital board of the CCD camera, its most important components, current implementation of firmware (VHDL) inside the FPGA and the role of external 8051 microcontroller is briefly described. The main goal of the presented work is to get rid of the external microcontroller and to design new system with Nios II processor built inside FPGA chip. Constraints for implementing the design into the existing camera boards are discussed. New possibilities offered by a larger FPGA for next generation of cameras are considered.

This paper holds an information about an extension module for Single Board Computer (MIP405), which is the heart of On-board Data Handling Module (OBDH) of student Earth's microsatellite - SSETI ESEO. OBDH is a PC104 stack of four boards electrically connected and mechanically fixed. On-Board Computer is a key subsystem to the mission success - it is responsible for distribution of control signals to each module of the spacecraft. It is also expected to gather critical data for an appropriate mission progress, implementation of a part of algorithms used for satellite stabilization and orbit control and, at last, processing telecommands. Since whole system should meet spaceborne application requirements, it must be exceptionally reliable.

We describe the performance evaluation of a sample of InGaAs detectors from which the best unit had to be selected for the flight model of the SIR-2 NIR-spectrometer to be flown on the Chandrayaan-1 mission in 2008.

The experiments of High Energy Physics (HEP) at the big accelerators with counter propagating beams serve for research on matter structure, properties and internal reactions. Contemporary HEP experiments are commonly done by elementary particle and nuclear physicists and engineers from many branches of technical sciences. The cutting edge level of technical complication of the experiments requires new research rather than off-the-shelf solutions. Such solutions are adopted as results of separate, large and expensive research programs, organized around a major experiment. One of the technical branches contributing essentially to the HEP experiments results is photonics and electronics. Recent application of fast, multi channel, distributed and synchronous photonic and electronic TRIDAQ systems, provides the HEP experiments with the improved space and time resolution at the measurements of positions, momenta and energies of elementary particles. TRIDAQ systems improve the selection processes of physical events (TRIgger part of the system), and the registration of relevant data (Data AcQuisition of the system). Part I of the paper discusses overall TRIDAQ system architecture, while part II of the paper shows TRIDAQ system solutions for BAC and CMS detectors, comparing the performance differences caused by two decades of system exploitation and design.

The paper debates design, construction, commissioning and exploitation of photonic and electronic TRIDAQ systems for two generations of HEP experiments. The Author participated personally in these developments during the last two decades. TRIDAQ system for Backing Calorimeter at HERA accelerator in DESY was presented. It was exploited during the period of 1991-2007. RPC Muon Trigger in CMS experiment at LHC accelerator was also presented. It will be exploited during the period of 2008-2015. Both TRIDAQ systems were designed, optimized and constructed for particular HEP experiment, thus, they have a unique functional structure. There are presented evolution of functional requirements of TRIDAQ systems and used technologies adapting to the ever changing research demands.

The paper describes the hardware and software architecture of a control and measurement system for electromagnetic field stabilization inside the radio frequency electron gun, in FLASH experiment. A complete measurement path has been presented, including I and Q detectors and FPGA based, low latency digital controller. Algorithms used to stabilize the electromagnetic field have been presented as well as the software environment used to provide remote access to the control device. An input signal calibration procedure has been described as a crucial element of measurement process.

The paper presents a procedure and laboratory setup for calibration of extreme ultraviolet detectors. The procedure determinates a responsivity of a photodiode applied in the technology of EUV radiation. The main elements of the described system are a gas-puff laser plasma source, metrology chamber with an optical beam splitter and a model instrument. The applied measurement method is based on a comparison of the detected signals from the model instrument and the tested detector. The reduction of an error resulting from instabilities of the source radiation is ensured using a special construction of the optical beam splitter. Because of the cost and the metrology features, the presented setup is future alternative for small factories and laboratories producing EUV detectors. In the paper, analysis and preliminary research of the setup are described.

A digital control, as the main part of the Low Level RF system, for superconducting cavities of a linear accelerator is presented. The FPGA based controller, supported by MATLAB system, was developed to investigate a novel firmware implementation. The complex control algorithm based on the non-linear system identification is the proposal verified by the preliminary experimental results. The general idea is implemented as the Multi-Cavity Complex Controller (MCC) and is still under development. The FPGA based controller executes procedure according to the prearranged control tables: Feed-Forward, Set-Point and Corrector unit, to fulfill the required cavity performance: driving in the resonance during filling and field stabilization for the flattop range. Adaptive control algorithm is applied for the feed-forward and feedback modes. The vector Simulator table has been introduced for an efficient verification of the FPGA controller structure. Experimental results of the internal simulation, are presented for a cavity representative condition.

Research in physics, biology, chemistry, pharmacology, material research and in other branches more and more frequently use free electron lasers as a source of very intense, pulsed and coherent radiation spanning from optical, via UV to X-ray EM beams. The paper presents FLASH laser, which now generates VUV radiation in the range of 10-50nm. The role of low level radio frequency (LLRF) control system is shown in a superconductive linear accelerator. The electron beam from accelerator is injected to the undulator, where it is "converted" to a photon beam. The used LLRF system is based on FPGA circuits integrated directly with a number of analog RF channels. Main part of the work describes an original authors' solution of a universal LLRF control module for superconductive, resonant cavities of FLASH accelerator and laser. A modular construction of the module was debated. The module consists of a digital part residing on the base platform and exchangeable analog part positioned on a number of daughter-boards. The functional structure of the module was presented and in particular the FPGA implementation with configuration and extension block for RF mezzanine boards. The construction and chosen technological details of the backbone PCB were presented. The paper concludes with a number of application examples of the constructed and debugged module in the LLRF system of FLASH accelerator and laser. There are presented exemplary results of quality assessment measurements of the new system board.

The paper describes a design of configurable interfaces bridge implemented on universal PMC expansion module, equipped with programmable VLSI FPGA circuits. The basic functional characteristics of the device and the possibilities of its usage in many work modes are presented. Realization of particular blocks of the device and new hardware layer solutions are also characterized.

The paper describes a VME-board extension Data Acquisition card with field-programmable gate array (FPGA) circuit, which controls four separate analog channels. There are discussed the basic functional characteristics, some resolution improvement solutions, FPGA configuration, PCI connection, power filtering and a new hardware layer technology.

This paper includes a description of a prototype DAC plus Vector Modulator board and process of starting the system up. The idea of vector modulation and its limitations are also discussed below. The board is a part of the LLRF system, which provides the control of a superconductive accelerator and free electron laser. The article describes the hardware project implementation of the system. The PCB structure of the designed board is presented. New ideas of improvements for the next version of high power klystron driver are discussed.

This paper describes hardware and software concept of Universal Controller Module (UCM), a FPGA/PowerPC based embedded system designed to work as a part of VME system. UCM, on one hand, provides access to the VME crate with various laboratory or industrial interfaces like gigabit optical links, 10/100 Mbit Ethernet, Universal Serial Bus (USB), Controller Area Network (CAN), on the other hand UCM is a well prepared platform for further investigations and development in IP cores field, in functionality expansion by PCI Mezzanine Card (PMC).

This paper presents a new reconfigurable architecture created in FPGA which is optimized for DSP algorithms like digital filters or digital transforms. The architecture tries to combine advantages of typical architectures like DSP processors and datapath architecture, while avoiding their drawbacks. The architecture is built from blocks called Operational Units (OU). Each Operational Unit contains the Control Unit (CU), which controls its operation. The Operational Units may operate in parallel, which shortens the processing time. This structure is also highly flexible, because all OUs may operate independently, executing their own programs. User may customize connections between units and modify architecture by adding new modules.

The low level RF control system (LLRF) of FEL serves for stabilization of the electromagnetic (EM) field in the superconducting niobium, resonant, microwave cavities and for controlling high power (MW) klystron. LLRF system of FLASH accelerator bases on FPGA technology and embedded microprocessors. Basic and auxiliary functions of the systems are listed as well as used algorithms for superconductive cavity parameters identification. These algorithms were prepared originally in Matlab. The main part of the paper presents implementation of the cavity parameters identification algorithm in a PowerPC processor embedded in the FPGA circuit VirtexIIPro. A construction of a very compact Matlab script converter to C code was presented, referred to as M2C. The application is designed specifically for embedded systems of very confined resources. The generated code is optimized for the weight. The code should be transferable between different hardware platforms. The converter generates a code for Linux and for stand-alone applications. Functional structure of the program was described and the way it is acting. FLEX and BIZON tools were used for construction of the converter. The paper concludes with an example of the M2C application to convert a complex identification algorithm for superconductive cavities in FLASH laser.

The European XFEL project uses the LLRF system for stabilization of a vector sum of the RF field in 32 superconducting cavities. A dedicated, high performance photonics and electronics and software was built. To provide high system availability an appropriate test environment as well as diagnostics was designed. A real time simulation subsystem was designed which is based on dedicated electronics using FPGA technology and robust simulation models implemented in VHDL. The paper presents an architecture of the system framework which allows for easy and flexible conversion of MATLAB language structures directly into FPGA implementable grid of parameterized and simple DSP processors. The decomposition of MATLAB grammar was described as well as optimization process and FPGA implementation issues.

Processing of large amount of data for high energy physics experiments is modeled here in a form of a multichannel, distributed measurement system based on photonic and electrical modules. A method to control such a system is presented in this paper. This method is based on a new method of address space management called the Component Internal Interface (CII). An updatable and configurable environment provided by FPGA fulfills technological and functional demands imposed on complex measurement systems of the considered kind. A purpose, design process and realization of the object oriented software application, written in the high level code described. A few examples of usage of the suggested application is presented. The application is intended for usage in HEP experiments and FLASH, XFEL lasers.

The properties of niobium films obtained by cathodic arc deposition in ultra high vacuum (UHVCA) using constant and pulsed bias are discussed and compared. UHVCA-produced Nb films are found to have structural and transport properties closer to Nb bulk ones, providing a promising alternative for niobium coated, high voltage, high Q, copper RF cavities with respect to the standard magnetron sputtering technique. A series of sapphire substrate coatings with niobium has been performed at pulsed bias and compared with the films deposited at cd bias. Using pulsed bias resulted in increasing an average deposition ratio by a factor of 2-3 up to a value of 0.9 μm/min. The layers coated with pulsed bias reached higher RRR values. Their microstructure is characterized by much larger, randomly oriented grains, compared to the layers obtained with constant bias, with no evidence of epitaxial growth and a lattice parameter identical to that of bulk niobium. The apparatus for coating of a cavity using planar UHVCA sources is presented and discussed. First results on plasma transport into a cavity cell are presented showing that it is possible to guide the plasma generated by a planar arc source inside it. Several magnetic configurations have been analyzed and different voltage bias used.

Phase and amplitude stabilization of accelerating field is a challenging task, which usually requires dedicated hardware and software. In this contribution, we introduce briefly parameters of an accelerating structure and basic measurements on the test stand with copper structure, helping to improve control systems required for stable operation of accelerating structures.

The paper presents preparation of film composed of Pd nanocrystals embedded in carbonaceous matrix and characterization of their characteristics, such as structure and optical properties. Pd nanocrystalline films were obtained by the physical vacuum deposition method (PVD) and were studied by TEM, AFM and optical absorption (UV-VIS absorption) methods. Pd nanocrystals have structure of fcc type and are embedded in matrix based on fullerene structure of fcc type. The interaction between Pd and elements of carbon matrix interface were studied by UV-VIS absorption spectroscopy.

The direct electrodeposition makes many useless problems in the thermoplastic industry. One of these is an edge effects problem. The first computer modeling helps to solve this problem. One of the greatest influences of this problem's solution has electric field intensity. It's involving dependence on potential distribution and current density distribution. Two methods of the edge effects decreasing are applied to analyze the direction of the electric field intensity vector. It shows how useful is the ability of electric field forming and how it helps in the electrochemical covering technology.

The Pierre Auger Observatory is an international project for research on ultra-high energy cosmic rays (UHECR) above 10¹⁹ eV and currently the world largest "hybrid" experiment. The hybrid technique uses both the detection of particles at the ground in water Cherenkov detectors (WCD) and measurements of fluorescence light generated in the atmosphere by the extensive air showers. This technique offers unique possibilities for cross-calibration and reduction of measurement uncertainties. The surface array will contain 1600 surface detector stations distributed over 3000 km² in the Southern Hemisphere (under construction in Argentina) and 4000 WCD distributed over 10000 km² at a Northern Hemisphere site in Colorado (deployment planned for 2008). Four fluorescence stations each containing 6 wide-angle Schmidt telescopes and each equipped with 440 PMTs with 1.5° angle resolution and 30 • 30° of field of view are located on the border of the surface array in the Southern Site. The paper presents implementations of the FPGA used for triggering. The use is illustrated with currently working schemes as well as other possible ideas especially promising for the surface detector in which currently used triggers seems to be not effective enough for very inclined and horizontal showers. Proposed new triggers enlarge a simple 1-bit threshold detection to the online analysis of a FADC trace shape. This corresponds to a charge from PMTs or signal power estimation. The next category is spectral triggers analyzing sequential samples in the frequency domain. Digital sigma-delta filters immunize the trigger circuitry on the pedestal variation as results of huge temperature swings. Presented DCT trigger provides native pedestal independence.

A new acquisition system has been developed to allow the measurement of an individual intensity of each bunch in a bunch train. Such a system will be used for the measurement of beams at the injection, ejection and acceleration lines. The method is based on integrating of the analogue signal supplied by a Beam Current Transformer (BCT). The signal is sampled by two 12 bits ADCs. The output of the ADC is then processed in the FPGA, where the rest of the signal processing is performed. In case of the Proton Synchrotron (PS), special synchronization algorithm has been developed. The measurement system was build as a standard VME module. Apart from that, on the same board there were implemented current and charge calibrators.

Stability and precision of signal controlling particle accelerator is very complex problem. Most sophisticated analog design of vector modulator sometimes cannot provide signal with satisfying parameters. This paper present possible future solution using less components than analog vector modulator. There are described two options, one is digital vector modulation with analog upconversion and second one is full digital synthesis.

Reliability of new, advanced electronic systems becomes a serious problem especially in places like accelerators and synchrotrons, where sophisticated digital devices operate closely to radiation sources. One of the possible solutions to harden the microprocessor-based system is a strict programming approach known as the Software Implemented Hardware Fault Tolerance. Unfortunately, in real environments it is not possible to perform precise and accurate tests of the new algorithms due to hardware limitation. This paper highlights the AVR-family microcontroller simulator project equipped with an appropriate monitoring and the SEU injection systems.

Paper presents the CAD system, referred to as PeNCAD, which supports the design of logic controllers. The system developed at the University of Zielona Gora allows designing concurrent logic controllers specified by means of Petri net. The designed control system is implemented in the reprogrammable FPGA structure. The further development of the system has been discussed in details regarding the application of the partial reconfiguration systems. The use of the partial reconfiguration FPGA-based systems in the process of logic controllers' design enables to increase their flexibility and functionality. Additional consequences come in the form of the decrease in hardware requirements needed for the implementation processes of the logic controller. The reconfiguration consists in replacing of the subnet associated with a macroplace. The Xilinx FPGA devices were used while carrying out the tests.

Photoacoustic measurements are quite often performed by means of data acquisition systems that collect samples of the photoacoustic signal, and use the samples for the purpose of calculation of the amplitude of its fundamental frequency. The most common method of such calculations is the FFT, but the amplitude can be also obtained by means of the least mean square (LMS) method. The paper compares properties of both methods from the point of view of their numerical efficiency and errors vs. S/N ratio and number of samples per period of the investigated signal. The discussion shows that in the case of an integer number of periods sampled, results of the FFT and LMS are identical, but due to higher numerical efficiency the LMS method should be used.

The paper presents a comparison of acousto-electrical models of Helmholtz resonator in photoacoustic applications. Different definitions of model with lumped elements were compared with a transmission line model and experimental data.

The paper presents a pulse generator dedicated for time domain relectometry system. The idea of the pulser delivering step pulses with picosecond transition time together with its experimental realization are described. Main features of the presented pulser are: the circuit for shaping output pulses consisting of several stages (each of them containing Step Recovery Diode) connected by inverted microstrip line and the controlled delay of the (also generated) oscilloscope trigger pulses. Time-domain measurement illustrate the achieved results.

The paper presents a low-cost trigger circuit for use in sampling oscilloscope with bandwidth in order of hundreds of MHz. The presented dual-step trigger circuit provides relatively high bandwidth because of significant reduction of possibility of incorrect turning on in trigger circuit flip-flop (caused by circuit instability called tremor or - describing the same phenomenon by other means - its metastability. The paper presents a circuit structure, principle of operation and its physical realization.

This paper presents statistical algorithm and measurement system for precise evaluation of flip-flop dynamical parameters in asynchronous operation. The analyzed flip-flop parameters are failure probability, MTBF and propagation delay. It is shown how these parameters depend on metastable operation of flip-flops. The numerical and hardware solutions shown in article allow for precise and reliable comparison of flip-flops. Also the analysis of influence of flip-flop electrical parameters of flip-flop electrical parameters on their metastable operation is possible with use of presented statistical method. Statistical estimation of parameters of flip-flops in which metastability occurs, seems to be more reliable than standard empirical methods of flip-flop analysis. Presented method allows for showing inaccuracies in theoretical model of metastability.

The project is realized as a diploma thesis in Bialystok Technical University (Poland). The main aim is to develop a useful educational tool which presents the time and frequency characteristics in basic electrical circuits. It is designed as a helpful instrument for lectures and laboratory classes. The predominant audience will be students of electrical engineering from first semester of the higher education. Therefore the level of knowledge at this stage of education is not high enough and different techniques are necessary to increase the students' interest and the efficiency of teaching process. This educational instrument provides the needed knowledge concerning the basic circuits and its parameters. Graphics and animations of the general processes in the electrical circuits make the problems more interesting, comprehensive and easier to understand. For designing such an instrument the National Instruments' programming environment LabView is used. It is preferred to the other simulation software because of its simplicity flexibility and also availability (the free demo version is sufficient to make a simple virtual instrument). LabView uses graphical programming language and has powerful mathematical functions for analysis and simulations. The useful visualization tools for presenting different diagrams are worth recommending, too. It is also specialized in measurement and control and it supports a wide variety of hardware. Therefore this software is suitable for laboratory classes to present the dependencies between the simulated characteristics in basic electrical circuits and the real one measured with the hardware device. For this purpose a two-channel oscilloscope is designed as part of the described project. The main purpose of this instrument as part of the educational process is to present the desired characteristics of the electrical circuits and to become familiar with the general functions of the oscilloscope. This project combines several important features appropriate for teaching purposes: well presented information with graphics, easy to operate with and giving the necessary knowledge. This method of teaching is more interesting and attractive to the audience. Also the information is assimilated more quickly, with less effort.

A subject of the paper is a review of the basic properties of several families of high optical quality glasses and metaglasses for photonics. The emphasis is put on nonlinear properties of these glasses, including nonlinearities of the higher order. Nonlinear effects were debated and systematized. Interactions between optical wave of high power density with glass were described. All parameters of the glass increasing the optical nonlinearities were categorized. Optical nonlinearities in glasses were grouped into the following categories: time and frequency domain, amplitude and phase, resonant and non-resonant, elastic and inelastic, lossy and lossless, reversible and irreversible, instant and slow, adiabatic and non-adiabatic, with virtual versus real excitation of glass, destroying and non-destroying, etc. Nonlinear effects in glasses are based on the following effects: optical, thermal, mechanical and/or acoustic, electrical, magnetic, density and refraction modulation, chemical, etc.

This is the second part of a paper on nonlinear properties of optical glasses and metaglasses. A subject of the paper is a review of the basic properties of several families of high optical quality glasses for photonics. The emphasis is put on nonlinear properties of these glasses, including nonlinearities of higher order. Nonlinear effects were debated and systematized. Interactions between optical wave of high power density with glass were described. All parameters of the glass increasing the optical nonlinearities were categorized. Optical nonlinearities in glasses were grouped into the following categories: time and frequency domain, amplitude and phase, resonant and non-resonant, elastic and inelastic, lossy and lossless, reversible and irreversible, instant and slow, adiabatic and non-adiabatic, with virtual versus real excitation of glass, destroying and non-destroying, etc. Nonlinear effects in glasses are based on the following effects: optical, thermal, mechanical and/or acoustic, electrical, magnetic, density and refraction modulation, chemical, etc.

In Er:YAG, Er:YSGG and Er:YLF lasers the most important are the three lowest energy levels of Er³⁺ ion. Transitions between these levels decide about wavelength of generated laser radiation. In Er:YAG laser these levels are: ⁴I_15/2 (energy: 280 cm^-1), ⁴I_13/2 (6710 cm^-1), ⁴I_11/2 (10330 cm^-1) [1]. Er:YAG has many absorption lines mainly in visual and near infrared wavelength spectrum. This laser may generate optical radiation at two wavelengths: 1,6 μm and 2,94μm. For the first one Er:YAG works as a three level quantum system and the for the second one it works as a four level quantum system. In this case the top laser level is ⁴I_11/2 and the down laser level is ⁴I_13/2. Both the wavelength generated and the work mode may be selected by dopant concentration. In lasers such as Er:YAG an analysis of transitions between levels during optical radiation absorption and generation the Boltzman distribution of energy levels occupation and thermalization effects must be taken into consideration [2]. Authors have developed computer software, which allows analysing transitions dynamics, laser output power/energy and rod's temperature increase (during pulse generation) which depends on: pump properties, initial temperature, and dopant concentration. Analysis may be carried on for monopulse generation as well as for pulse generation. This software allows simplifying Er:YAG laser application designing.

Proof-of-concept, rate-equation based model is present to asses feasibility of population inversion build-up for novel optical transitions in Ho³⁺ doped ZBLAN fibres. Measured, fundamental spectroscopic parameters, as well as fibre cross-section geometry are taken into account, yielding preliminary conditions of population inversion for optical transitions from ³D₃ state under direct and up-conversion excitation.

The optical and physical properties of three different glass systems were presented. The obtained glasses were doped with 1,75wt% erbium oxide (Er₂O₃). Transmission and luminescence spectra were measured. Absorption spectra were calculated on the basis of transmission spectra. Classic active optical fiber doped with 1,75wt% erbium oxide was fabricated. Attenuation of fabricated optical fiber was measured.

This paper is devoted to the dynamic characteristics of EDFA (Erbium Dopped Fiber Amplifiers). The relaxation time measurements are presented here in the input signal function, relaxation time testing results in the wavelength function as well as the examination of input signal impact on pumping laser beam.

This paper presents theoretical analysis of impulsive strain processing by fiber Bragg Grating (FBG) with linearly changeable period. Tensile and compression excitations acting along the longitudinal fiber axis are studied. The prepared calculation is based on the piecewise-uniform period assumption for chirped grating. Then the obtained reflected spectrum is analyzed by calculating its centroid frequency. This allows it to calculate rise time error as a function of length of distortion leading edge and grating length which allows it to establish influence of grating length on processing accuracy.

The results of the fiber Bragg grating reconstruction problem were introduced in this work. This process was conducted by using of Genetic algorithm. The proposals of the ways of modeling structures of fiber Bragg gratings by the use of the object-oriented programming and by the use of the direct and inverse problem were introduced in this article.

The method of polarization fibres manufacturing and the results of geometrical measurements of obtained optical fibres are presented. The essential aspect of examinations is the analysis of the influence of technological parameters on geometrical measurements of obtained polarization fibres. In the frames of present work made were four structures of optical fibres: type of side-hole with elliptical core and the completely new structure, not examined theoretically still and not realised practically yet, named AZ-K7 with rectangular stress elements and with classical core.

In the Department of Optical Radiation, Bialystok University of Technology have been made new structures of polarization fibres. The paper present properties of obtained fibres and describe the influence of geometry of an optical fibre on its parameters i.e. numerical aperture, attenuation, beat-length, temperature resistance.

In this paper we present synthesis, physical and optical properties of silica based glass doped with 1,5% wt. neodymium ions. The stable silica glass without crystallization effect was synthesized. Fabricated glass was applied as core to obtain double clad optical fibers. Rod-in-tube method drawing technique was used to fabricate double clad optical active fibers with D- profile inner cladding. Absorption and luminescence spectra of obtained fibers were measured.

This paper presents the proposition of a novel multi-parameter method for examination of liquids using optical capillaries. Unlike other well-known fiber optical sensors for liquids that utilize spectral information of the index of refraction and optical signal attenuation, the proposed method takes advantage of additional information originating from surface tension, viscosity, boiling point, vapor pressure of liquid and its heat capacity. In the proposed configuration with short sections of capillary of an inner diameter up to 300μm, the capillary effects enable hydrophilic liquid sampling without using an additional pump. The results obtained by us show that optical capillary tubing can be used as sensing elements in multi-parameter photonic sensors of small liquid samples with volume below 10^-8 cm³.

Possibility of employing Mode Group Diversity Multiplexing (MGDM) to increase the information capacity of Multimode Fibers is investigated. Gaussian beam light launch method for excitation of non-overlapping mode groups is analyzed. Far field analysis for separation of mode groups at the fiber output is proposed. Numerical results, presented for both parabolic and step index multimode fibers, show that step index fiber is preferable in terms of MGDM system design.

This article presents the construction and the measurement results for incremental optical fibre transmission and reflection sensors. This work elaborates on the construction and properties of the measurement heads with a single comb diaphragm, two diaphragms and a head comprising two independent measurement channels.

The paper presents temperature sensor based on double layer capillary waveguide. The basics of mathematical calculation of guiding light through double layer capillary are presented. The fabrication process and properties of double layer capillary waveguide are showed. The practical application for monitoring of high-temperature industrial oil is shown. The paper contains the obtained characteristic of the temperature sensor.

In the paper the battery energy storage system is presented. 40 kVA BES was installed in Electrical Drive and Power Electronics Department of Bialystok Technical University. The article presents the new way of control the battery energy storage through the active power filter. Because of the power coefficient cosφ decrease and input current deformation the battery energy storage system was equipped with active filter to current distortion elimination. The active power filter's control system uses the optical track which is based on optical fibre. Insensibility important is on the large electromagnetic field in the arrangement of control. This assures the optical system. The test of the implementation of the optical track was introduced in the arrangement IPM among the control system and inverter.

In the paper, the selected results of the using a CCD camera to record effects of luminescence occurring in a multi-LED matrix are given. A structure of the measuring system and parameters of applied elements are presented. The images get from the CCD camera are compared for different configurations of shining and not-shining LEDs creating a given matrix. An analysis of possible interaction between optical signals emitted by adjacent diodes has been made. The studies are focused on the important metrological problems resulting from technical parameters of the CCD camera, elements applied to signals conditioning and existing conditions of the measurement. Especially, the time limitations in recording the luminescence effects, when to use the CCD camera for their recording, are considered.

The article describes methodology and results of research on remote optical power supply at low illumination levels. Such approach is a result of studies on passive optical networks extended with optically powered active components made beforehand.

Atom guidance in capillary hollow fibres is discussed in detail. The main properties and the differences between the guidance with the blue and red detuning are described. Since the blue guiding has several advantages over the red guiding we focus on this type of guidance. Rubidium atoms are ideal for investigating atom transport by reason of their quantum properties. The influence of capillary features (radius of the hole, radius of the core, refractive index of the core) on transmission parameters is investigated and described in detail.

In this paper is presented the subject of Polarization Mode Dispersion - PMD, that is characteristic for single mode optical fiber transmission. There is shown interferometric method of measurement PMD and example statistical analysis of measurement results, and a way of making conclusions.

In the paper the results of ORMOSIL gels' structures' investigation were presented. As a method XRD (X-ray diffraction) was applied. ORMOSIL gels comprising phenyl and methyl groups may be used as matrices for active layers in optical fibre sensors because an organic dye acting as a transducer may be easily introduced into their network during a so-called sol-gel process. Moreover, the refractive index of such layers may be modified by changing a molar ratio of different alkoxysilanes in a sol. As a signal of an UV optical fibre sensor strongly depends on sols' composition and ageing time it could be suggested that the structure of the gel may influence the behaviour of the dye. XRD method enables determining positions and distances between molecules, positions of atoms, angles' and bonds' lengths between atoms, distribution of electron's cloud's density on atoms, dipole moment of bonds and molecules as well as the nature of bonds, therefore it may be useful in examination of the structure of partially ordered elementary cell of the gel. The results may help to understand dependence between the structure of the gel and sensor's signal's value and lead to achieve a better performance of the optical fibre UV sensor.

A novel application of thick film technology (TFT) for creating a complete microstructure for capillary electrophoresis with contactless conductivity detection is presented. Elaborated microchip was made by bonding ceramic with a polymer. The photoimageable material (FODEL 6050, DuPont) was employed to creating microchannel (capillary) in the structure. It was due to merging thick film technology and photolithography. The contactless conductivity detector was equipped with two electrodes prepared with silver paste. The electrodes were separated from the microchannel by a dielectric layer. The functionality of the presented microchip was successfully verified by testing inorganic cations separation.

Electronic devices, components, circuits and microsystems continue to become smaller, lighter, faster and less expensive. The progress in hybrid microelectronics, especially in high density packaging and interconnections, is very much dependent on the achievements in developing new electronic materials. The paper presents the state of art of thick film materials as well as the new developments carried in Hybrid Mirocircuits and Microsystems Laboratory, which was established in 2006 by Warsaw University of Technology, Department of Electronics and Information Technology and Institute of Electronic Materials Technology.

A new thick film gold conductive composition for high temperature electronics was elaborated and tested. This paste was designed for metallization of the alumina substrates (Al₂O₃) for electrical interconnection system, e.g. for a silicon carbide Schotky diode. Also platinum pastes for conductive paths resistant to high temperatures (over 600°C) were elaborated by the authors. Several gold and platinum powders and glasses, as well as bonding oxides were examined to design a suitable composition. The influence of the paste composition and firing temperature on the layer properties was shown. The obtained layers were aged a 1000 hours at elevated temperatures (350°C). Sheet resistance of platinum and gold paths was measured. Mechanical strength and electrical resistance of wire bonds to the gold layers after aging were also examined. The electrical measurements were performed at room temperature and elevated temperature (150°C, 250°C, 350°C), using precise four-wire method. The microstructure of layers was also shown.

The RoHS and WEEE regulation forced the large investigations for environmental friendly materials in electronic. The Lead and cadmium which was the significant component of resistors and conductors used in thick-film technology have to be replaced. Quick and precise measurement techniques need to be elaborated to maintain consumer's demand. Usually the test samples with the conductive and resistive layers were used for electrical parameters measurements. The layer thickness measurements and mean value of resistance allowed calculating the sheet resistance. Such a method of measurement have very serious disadvantage. The calculated mean value can be significantly affected by resistors terminations, especially if silver conductor is used, which is known as an easily migrating material. The solution was known and involved preparing and printing samples with the reference terminations. Silver platinum and silver palladium conductors are less susceptible to migration, therefore they were used in previous investigations. The reference terminations improves the precision of calculating sheet resistance, however they enlarges the number of measurements and its influence could still be significant. The authors proposed completely new method of sheet resistance calculation. Such a calculated value called True Sheet Resistance do not depend on the phenomena taking place at the termination, The second evaluated value called Offset indicates the influence of the terminations on measured resistance, and also termination quality. Its value is correlated with the diffusion rate at the interface between conductive film and resistive film at the termination. The usability of this method was proven by performing multiple firing test. One kind of resistive layer was printed on different kinds of conductive layers. The samples were fired sequently and measured. Then the old method of resistor properties evaluation was compared to the new one.

We propose new approach for defect centers parameters extraction in semi-insulating GaAs. The experimental data is obtained by high-resolution photoinduced transient spectroscopy (HR-PITS). Two algorithms have been introduced: support vector machine - sequential minimal optimization (SVM-SMO) and relevance vector machine (RVM). Those methods perform the approximation of the Laplace surface. The advantages of proposed methods are: good accuracy of approximation, low complexity, excellent generalization. We developed SVM-RVM-PITS system, which enables graphical representation of Laplace surface, defining local area for defect parameter extraction, choosing the SVM or RVM method for approximation, calculation of the Arrhenius line factors and finally the parameters of the defect centers.

This paper prsents a method of detection of deep defect centres in semi-insulating materials, with usage of neural net application. Innovation of this work is based on implementation of local cluster activation function in standard scheme of neural network.

In this paper the application of on-line support vector machine to spectral surface approximation is presented. The experimental data were obtained by the photocurrent decay measurement as function of time and temperature for a sample of neutron irradiated silicon. This approach enabled to extract the deep level center defect parameters: activation energy and pre-exponential factor.

The least-squares support vector machines (LS-SVM) can be obtained by solving a simpler optimization problem than that in standard support vector machines (SVM). Its shortcoming is the loss of sparseness and this usually results in slow testing speed. Several pruning methods have been proposed to improve the sparseness of a LS-SVM trained on the whole training dataset. A selection of significative samples is proposed to train a LS-SVM on a reduced dataset. A dataset about electrocardiogram (ECG) of 376 patients has been used to assess the proposed algorithm.

New method of fabrication conductive paste for screen printing in thick film technology was investigated. Fabrication of electronic paste with addition of multiwalled carbon nanotubes and nanoscale silver powder leads to many technological problems in the stir process of nanosized particles. A specialist ultrasonic method was applied to obtain homogeneous mixture. To obtain paste with proper reological properties and usable in thick film technology a selection process of suitable organic resin was conducted. Obtained mixtures with optimal parameters will be used for further experiments.

The paper presents some analytical and experimental data on the observed perturbations in v'=11 of A¹Π state of ¹³C¹⁶O molecule. The results have impact on photonic properties of these molecules.

Now, we propose a simple method of the elasticity modulus measurements for textiles filament using a mechanical pulse spectrometer. These measurements were performed for the polyamide filaments with a diameter about 11μm. Also we reanalyze the factors giving an experimental error. Estimation of the measurement error for our elasticity modulus is of a range 6,7%.

New we propose a simple method of determination of Poisson's ratio for auxetic materials like the polyamide foams. These measurements were performed for the conventional materials and also auxetic foams. This method is based on a diffraction pattern observation using CCD camera connected to PC computer. The diffraction pattern are used for real-time monitoring of the foam diameters and their extension due to streach.

In recent years very fast progress in the domain of Optical Quantum Cryptography is observed both in theoretical and practical aspects. The paper is a short tutorial review of basic concepts of Optical Quantum Cryptography (OQC) and Quantum Key Distribution (QKD).

Lattice is regular arrangement of points in Rⁿ. The Closest Vector Problem (CVP) is defined as follow: given a point y in Rn and a lattice basis B find lattice vector Bx closest to y . The CVP problem is believed to be computationally intractable in average. Here we propose a new way to generate hard instances of CVP and a method that allows us to construct a cryptographic trapdoor function based on it. We start with brief introduction to lattices. Next we present a very natural application of lattices in cryptography, i.e. GGH cryptosystem and the way the system was broken. Finally we present our modifications way to generate hard instances of CVP, harder than previously proposed in GGH.

The paper introduces the Differential Current Mode Technology (DCMT) - a technique of providing very high security level for cryptographic devices. As distinct from the most Side Channel Attacks (SCA) preventing methods, the DCMT does not rely on concealing, masking or muffling, but minimizes the sources of the leakage. Digital circuits based on DCMT operate with constant and continuous supply current as well as symmetrical differential current-mode inner connections - all with the aim of keeping electromagnetic emanation and power supply disturbances as low as possible. The paper describes the general assumptions for the DCMT, basic model of the DCM-gate, three-valued DCM-logic, rules of differential current arithmetic and basics of binary computations on the basis of the DCMT. A crucial issue for the DCMT in the fields of security, efficiency, power consumption and implementation cost (size on an IC) is designing of current sources and sinks. Trade-off between supply current and propagation time, along with analyses of static and dynamic currents aberrations with regard to sizes of current sinks/sources are presented.

This paper describes the design path of a hard disk encryption device. It outlines the analysis of design requirements, trends in data security, presentation of the IDE transfer protocol and finally the way of choosing the method, algorithm and parameters of encryption.

The volatile character of laser beam and biological media interactions causes difficulties with respect to prediction of eventual parameters variations of the exposed medium. Accurate evaluation of the laser energy distribution in biological media helps to forecast the results of exposure. Together with the assumption of predetermined absorption model it constitutes very efficacious approach of the medium thermal profile estimation which is crucial with respect to tissue welding process [1].

Multileaf collimator (MLC) allows advanced field shaping for radiation therapy delivered with medical accelerators. In this paper theoretical considerations and scientific studies of a new MLC design are described. Considered multileaf collimator model comprises of a multiplicity of tungsten leaves of 1 cm width projected at isocenter plane. To ensure compatibility of a new MLC solution with different accelerator types as well as to assure high reliability in irradiated environment and presence of strong magnetic field, a complex and independent control system had to be developed. It comprises of two modules - one placed in the accelerator treatment head and the other one placed in the control room. Both of them ensure high reliability and treatment quality while working in harsh conditions. Mechanical design and leaf shape optimization algorithm based on a ray tracing method are also described in details. Adapted solutions allowed providing minimized and uniform radiation penumbrae in the full range of leaves positions which is crucial for modern advanced radiotherapy.

Medical linear accelerators are the largest group of devices for therapy of cancer diseases because of their compact design, relatively low operating costs, advanced features and broad range of treatment procedures. Their reliability and ease of operation are very important but the most crucial is to ensure personnel and patient safety. For this reason the development of control and safety systems is the current "leading edge" in medical linear accelerators technology. Provided internal monitoring, machine control and steering, interlock system as well as the automatic recording of the device and patient parameters are nowadays fully controlled by the computer. This paper describes in details projects connected to advanced development of Coline accelerators. As it is crucial to assure reliable steering and monitoring of all the machine settings and actual dose delivered to the patient, advanced control systems composed of steering, control and interlock systems, communication protocol as well as data management system have been developed.

This work presents a way of parallel computation of the Specific Absorption Rate distribution. The parallel program used in the computation was based on the FDTD (Finite-Difference Time-Domain) method [1,2,3]. In order to establish communication among the computational nodes, the MPI (Message Passing Interface) standard was used [4,5,6]. The presented example of a human head numerical model was built with the use of MRI (Magnetic Resonance Image) pictures.

Sensor networks are commonly used in a wide area of possible applications. In such network there is a great demand for data transmission. Data can be transmitted either by cable or wireless. This paper presents possible solution for data transmission - a wireless platform which consists of devices providing data acquisition, transmission and processing. The paper includes also construction and potential functions of the network node.

Wireless Sensor Networks (WSN) are currently very popular area of development. It can be suited in many applications form military through environment monitoring, healthcare, home automation and others. Those networks, when working in dynamic, ad-hoc model, need effective protocols which must differ from common computer networks algorithms. Research on those protocols would be difficult without simulation tool, because real applications often use many nodes and tests on such a big networks take much effort and costs. The paper presents Graphical User Interface (GUI) for simulator which is dedicated for WSN studies, especially in routing and data link protocols evaluation.

The paper describes design and construction of a two stream humidity generator with embedded electronic control unit. To achieve maximum device performance mass flow controllers and digital control were used. By this way it was possible to obtain higher accuracy, stability and repeatability than possible in generator with mechanical control.

This article describes the design and construction of diagnostic medical system for air temperature measurement in nasal cavity. Concept of three-point thermometer is connected with single point electronic thermometer for air temperature measurement in nasal cavity that was previously constructed [1]. Researches were done in Microsystems and Sensors Research Group (WUT) with cooperation of physicians and laryngologists from Otolaryngology Department, Military Medical Institute, Warsaw. Measurement system consist of microprocessor module which periodically collects samples of air temperature from different part of nasal cavity, measurement head with three temperature sensors, and computer software presenting on-line results, calculating breathing parameters and storing data in database. Air temperature is measured in nasal cavity, middle part cavity and nasopharynx during regular respiration process.

This paper presents the application of neural networks to the risk recognition of sustained ventricular tachycardia and flicker in patients after myocardial infarction based on high-resolution electrocardiography. This work is based on dataset obtained from the Medical University of Warsaw. The studies were performed on one multiclass classifier and on binary classifiers. For each case the optimal number of hidden neurons was found. The effect of data preparation: normalization and the proper selection of parameters was considered, as well as the influence of applied filters. The best neural classifier contains 5 hidden neurons, the input ECG signal is represented by 8 parameters. The neural network classifier had high rate of successful recognitions up to 90% performed on the test data set.

The paper contains brief introduction to the EU FP6 WARMER project. First EU activities in the field of environmental monitoring are overviewed, to place research activities of the project in a proper context. Then the fundamental goals of the project are defined and a set of research and engineering problems to be solved is formulated. The main part of the paper is focused on solving the problem of software development for data acquisition and local fusion of measurement data from many, possibly multiple-mode sensors.

This paper presents results of analyses of possible architectures for the 6^th FP WARMER project system with emphasis on hardware and software modularization. A short survey of different system architectures and evaluation criteria is presented, so as to rationalize selection of one of the architecture as a basis for further work and development. Following factors are taken into account during evaluation: flexibility of architecture, standardization (necessary interfaces), existing solutions, development and build costs, hardware resource sharing and openness for future changes and extensions. The best system architecture in author's opinion has been presented, and some implementation issues have been discussed.

The author of this report has been involved in analyses of possible implementation of Open Geospatial Consortium Sensor Web Enablement services in the 6^TH FP WARMER project. This paper is focused on the possible utilization of that standard for high level data processing, result delivery to the end-user and cooperation between WARMER system components, like satellites, surface measurement stations and data centers. Advantages and disadvantages of SWE services have been presented, and some implementation issues have been discussed.

This paper presents a novel model of potentiometric sensors sensitive to ions of valency one and two such as H⁺, K⁺, Na⁺, NH4⁺, Mg⁺, SO4^-, NO3^-, Cl^- appearing in environmental water resources. The proposed models are based on the physical description by Van den Berg and behavioral description by Nikolsky and Eisenmann for ion-selective membranes. The elaborated models are applicable for data fusion algorithms which may be useful in the EU FP6 WARMER project dedicated to a system for water pollution risk management.

The paper sums up investigations of electrical properties of potentiometric sensors that are under development in the EU FP6 WARMER project. There are 2 main goals of the empirical study: to determine minimum input resistance/bias current of data acquisition board and to determine the quality of analytical signal in DC and transient responses of the potentiometric sensors.

In the paper an approach to fuzzy description of image is proposed. It is based on the concept of fuzzy functions. The concept of fuzzy function is enlarged on fuzzy signals. Fuzzy Fourier transform introduced by author in earlier works is used and expanded here on other kind of fuzzy functions in order to describe distortions introduced by optical systems. The definition of two-dimensional fuzzy Fourier transform, inversion of transform, and fuzzy convolution are proposed and used to described image transformation.

The rapid development of the Internet in the early 1990s caused an explosive growth of publicly accessible multimedia resources. It created new viewpoint on storage, distribution and processing of enormous collections of images. Along with the development of the World Wide Web there is much effort dedicated to create a content-based image retrieval systems which are able to efficiently index, retrieve and manage large scale databases. In this paper we propose a color indexing method based on the Gaussian Mixture Model of color histograms. The model parameters serve as signatures enabling fast and efficient color image retrieval. In this paper we show that the proposed approach is robust to color image distortions introduced by lossy compression artifacts and therefore it is well suited for indexing and retrieval of Internet based collections of color images stored in lossy compression formats.

We discuss here an improved multidimensional scaling (MDS) algorithm allowing for fast and accurate visualization of multidimensional clusters. Unlike in traditional approaches we use a natural heuristics - N-body solver - for extracting the global minimum of the multidimensional, multimodal and nonlinear "stress function". As was shown earlier, the method is very reliable avoiding stuck the solver in local minima. We focus on decreasing the time complexity of the algorithm from Ω(N²) to O(N²) by eliminating from computations most of distances, which are irrelevant in reproducing the real cluster structure in low dimensional spaces. This way we can speed up MDS algorithm significantly (even in order of magnitude for large datasets) allowing for interactive immersion into the data by immediate on-screen manipulation on different data representations.

We propose several vector graph descriptors created on the basis of vertex rank measures such as PageRank, Hubs and Authorities or Betweenness Centrality. The descriptors are used for clustering artificial and real-world data. We present the comparison of descriptors with the use of criteria such as computational complexity, size and quality of clustering. The experiments were performed mainly on the sets of aerial photos transformed to graphs with the use of Harris corner detection and Delaunay triangulation. The results show that the introduced pattern vectors can be a lower dimensional, less computationally expensive and graph size independent alternative for spectral descriptors, such as defined by Wilson, Hancock and Luo in [1].

Localization of text areas in images of natural scenes is essential for many applications, including support for the blind, tourist support, traffic control and content-sensitive image or video databases. Algorithms for localization of scene text must overcome issues of non-uniform scene lighting, scene text variations and distortions etc. In the paper we present the results obtained for scene text detection algorithms operating on various image representation domains, as well as our work on an algorithm based on an ensemble of simple classifiers.

Statistical properties of the images obtained with the help of application of the method of the generalized portrait are investigated. Kernel estimates of probability density function of the average images are constructed. Statistical properties of the received images and initial image realizations are investigated. The Markov model for the description of the generalized portrait is offered. For the Markov model of a random process the kernel estimates of a probability density function are offered.

A stereo matching algorithm implemented in the stereovision system is presented. The algorithm provides dense depth or disparity maps necessary to perform 3D reconstruction of the observed scene. The term "dense" refers to the fact that the algorithm calculates depth value for each pixel of one of stereo images. Along with the implemented stereo matching algorithm, a method of its verification is proposed, by means of generating for each disparity map, a respective certainty map which holds information about likeliness that the respective disparity value was well chosen.

Colorization is a term introduced by W. Markle¹ to describe a computerized process for adding color to black and white pictures, movies or TV programs. The task involves replacing a scalar value stored at each pixel of the gray scale image by a vector in a three dimensional color space with luminance, saturation and hue or simply RGB. Since different colors may carry the same luminance value but vary in hue and/or saturation, the problem of colorization has no inherently "correct" solution. Due to these ambiguities, human interaction usually plays a large role. In this paper we present a novel colorization method that takes advantage of the morphological distance transformation, changes of neighboring pixel intensities and gradients to propagate the color within the gray scale image. The proposed method frees the user of segmenting the image, as color is provided simply by scribbles which are next automatically propagated within the image. The effectiveness of the algorithm allows the user to work interactively and to obtain the desired results promptly after providing the color scribbles. In the paper we show that the proposed method allows for high quality colorization results for still images.

One of the frequently investigated 3D modelling methods involves projection of structured light. Different light coding schemes were examined in numerous studies. One of the possible strategies is to project a grid of color elements with necessary spatial information encoded in it. Before doing so, the colors of the grid have to be chosen. This paper contains a report of the research carried out to develop a procedure which can be used to select the set of colors to form the grid. The method aims to be insensitive to external lighting conditions and to object's surface type, in terms of its color. The second stage of the study was devoted to creation of a color detection and segmentation algorithm which can be incorporated into grid identification pipeline.

This article is dealing with a practical method of hiding secret information in video stream. Method is dedicated for MPEG-2 stream. The algorithm takes to consider not only MPEG video coding scheme described in standard but also bits PES-packets encapsulation in MPEG-2 Program Stream (PS). This modification give higher capacity and more effective bit rate control for output stream than previously proposed methods.

Results of zonal compression applied for greyscale images with the use of Walsh and PWL transforms have been presented in the paper. Both transforms, belonging to the class of piecewise-linear transforms and the zonal compression method have been described. Zonal compression, based on the selection of a specified zone in the spectral domain, has been performed for various zone shapes. Results of experiments with the use of the described method have been enclosed. Compression effectiveness has been evaluated in the terms of the Mean-Square Error (MSE) and the Peak Signal-to-Noise Ratio (PSNR). Visual evaluation of the reconstructed images has been also taken into account.

This paper concerns algorithms related to analysis of fingerprint images in area of minutiae matching. Proposed solutions make use of information about minutiae detected from a fingerprint as well as information about main first order singularities. The use of first order singularities as a reference point makes algorithm of minutiae matching more efficient and faster in execution. Proposed algorithms concern efficient detection of main singularity in a fingerprint as well as optimization of minutiae matching in polar coordinates using main singularity as a reference point. Minutiae matching algorithm is based on string matching using Levenstein distance. Detection of first order singularities is optimized using Poincare's index and analysis of directional image of a fingerprint. Proposed solutions showed to be efficient and fast in practical use. Implemented algorithms were tested on previously prepared fingerprint datasets.

Currently, one of the actual problems is remote monitoring of technical state of large objects. Different methods can be used for that purpose. The most promising of them relies on application of ground based synthetic aperture radars (SAR) and differential interferometry. We have designed and tested Ground Based Noise Waveform SAR based on noise radar technology [1] and synthetic aperture antennas [2]. It enabled to build an instrument for precise all-weather monitoring of large objects in real-time. We describe main performance of ground-based interferometric SAR which uses continuous Ka-band noise waveform as a probe signal. Besides, results of laboratory trials and evaluation of its main performance are presented as well.

The work is devoted to elaborating a new method for SAR image generating using noise/random signals and nonmoving & non-switching antenna array suggested in [1]. The main idea of that antenna array consists in the extraction from the total signal of one channel receiver the signals received by a single element of the array. This signals separation is based upon decorrelation properties of noise/random signals. Attractive advantages of the suggested antenna array and the method for SAR imaging consist in no need in either mechanical motion or electronic switching of the antenna array elements, which simplify its design and lower the cost. Analytical evaluations for main performance of such antenna array are given for its various implementations. The related SAR imaging algorithm is described in detail. Some results of computer modeling of SAR imaging using this antenna array are presented. Advantages and constrains of the method and array suggested are discussed.

The phase gradient autofocus (PGA) technique is used for automatic estimation and correction of phase errors in spotlight mode synthetic aperture radar (SAR) imagery. This paper presents an overview of the PGA algorithm in iterative and non-iterative versions and shows the results of implementation of this method in C language for real-time applications.

The paper presents an analysis of the influence of coherent integration time on tracking performance in PCL (Passive Coherent Location) radar. The analysis is carried out for standard "m of n" logic and is based on Markov chains. Parameters such as average true track confirmation time and probability of false track confirmation are calculated for different values of integration time. Exemplary results are presented for "2 of 3" logic.

One of the challenging problems in modern radar applications is the task of "Non-Co-operative Target Identification" (NCTI). Under many circumstances it is highly important to find out about the class or even identity of a target under observation without a co-operative support of this object. Especially for air-targets, but also for targets on the ground, presently at many places in the world classification methods are investigated, which are based on radar imagery of these targets. In case of a one-dimensional image we speak of "High-Range Resolution"-profiles (HRR-profiles) of the object under consideration, but also two dimensional images gained via SAR or ISAR methods could be used. The following paper deals with the identification of air-targets using HRR-profiles.

This paper describes two experimental prototypes of FM radio based passive radar receivers developed and fielded at the INFOCOM Dept. of the University of Rome "La Sapienza". The two prototypes are based on two different design approaches: direct IF sampling and signal down-conversion & baseband sampling. The acquisition campaigns that have been carried out with the two prototypes are described together with the collected data analysis and processing. Specifically, we consider the high diversity of the FM radio signals received over different carrier frequencies spanning the 88÷108MHz received bandwidth since it represents the basis for the request of a multi-frequency operation. The joint exploitation of the opportunity waveforms received on multiple FM radio channels is shown to yield better performance in terms of detection capability. To this purpose, the results obtained over the collected data set for the single FM channels and after a proper multi-frequency integration procedure are reported and compared.

This paper presents colour mapping technique for strip-mode SAR images as a extension of classic SAR imaging process. The main goal of this technique is to get more information from the SAR raw radar data about the observing objects and recognized them. The colour mapping technique is based on the well known multilook processing. The idea of colour mapping is to take advantages of Doppler history in the azimuth direction from N-independent looks. The whole propose algorithm consists of three general stages: motion compensation, multilook processing and the colour mapping technique.

The paper presents a study of effective resampling techniques to be used for stretch processing in Passive Coherent Location radars. In a typical PCL radar, two signals are correlated: one coming from a reference antenna pointed at a transmitter of opportunity, other coming from a search antenna pointed at the observed area, seeking the reflection of radio signal from a target. If the second antenna receives an echo from a moving target, the correlation of the two signals is disturbed by Doppler effect, consisting of frequency shift and envelope dilation. In order to compensate for this second effect, the reference signal has to be stretched (or dilated) by resampling. In the paper the review of applicable resampling methods is performed. The useful method should give results good enough for the correlation process, and it has to be very fast in the implementation, as the processing is to be done in real time.

The paper presents a concept of the simple robustification of correlation detector in the continuous wave noise radar. It was assumed that the received signal was distorted with additive -stable noise. The simulation results show that using nonlinear transformation of the received signal prior to correlation it is possible to improve the radar sensitivity in the non-Gaussian impulsive environment by several dB.

In this paper we present a simple SAR radar demonstrator build using commercially available (COTS) components. For the microwave analog front end, a standard police radar microwave head has been used. The Motorola DSP processor board, equipped with ADC and DAC, has been used for generating of modulating signal and for signal acquisition. The raw radar signal (I and Q components) have been recorded on 2.5" HDD. The signal processing has been performed on standard PC computer after copying the recorded data. The aim of constructing simple and relatively cheap demonstrator was to provide the students the real-life unclassified radar signals and motivate them to test and develop various kinds of SAR and ISAR algorithms, including image formation, motion compensation and autofocusing. The simple microwave frontend hardware has a lot of non-idealities, so for obtaining nice SAR image it was necessary to develop the number of correction algorithms at the calibration stage. The SAR demonstrator have been tested using car as a moving platform. The flight tests with a small airborne platform are planned for the summer.

Some basic properties of analog and discrete time-invariant systems with lumped fuzzy parameters are presented. It was assumed that parameters are fuzzy numbers. Description of the system is given in time and frequency domain. It was shown that amplitude and phase response of the system is fuzzy number for any frequency. Two ways of calculation of output signal are proposed. First method is based on the concept of fuzzy convolution. Second method uses idea of Fourier transform of fuzzy function proposed earlier by the author. Similar discussion was pursued for discrete systems.

A system for auditory presentation of 3D scenes to the blind is presented, with the focus of the paper on the synthesis of sound codes suitable to carry important scene information. First, a short review of existing electronic travel aids for the blind (ETAs) is provided. Second, the project of the wearable ETA device, currently under development at the Technical University of Lodz, is outlined, along with the system modules: 3D scene reconstruction, object (obstacle) selection, synthesis of the sound code and the application of head related transfer functions (HRTFs) for generating spatialized sound. The importance of psychoacoustics, especially Bregman's theory of sound streams, is analyzed and proposed methods of sound code synthesis are presented, along with the software used for their verification.

Zero-Compression Method (ZCM) is a simple and effective algorithm that can be used to compress the digital data which consists of a significant numbers of zeros. The method has the ability to encode and decode the data with high processing speed and it has the ability to recover the stored data with minimum error and minimum storage area. On the other hand, the ZCM may have a wide practical value in storing data extracted from ECG signals. The method is implemented for various types of signals such as textual data, wavelet subsignals, randomly generated signals and speech signals. In this paper the coding and decoding algorithm is presented.

In the paper a new approach for estimating of the spoken language sound multivariate probability density is suggested. It is based on the use of a projection of a random process to the set of random variables, with the probability density defined as a product of two-dimensional densities. The estimates of two-dimensional probability densities are obtained with the help of filtering of the two-dimensional empirical characteristic function. Therefore, we are suggesting a nonparametric estimate of the characteristic function. On the basis of these estimates nonparametric algorithms of sound classification can be constructed. Examples for the sound probability density function estimates are suggested.

In the work is presented the concept of a precision matrix being the reverse of a covariance matrix and presented modifications of Kalman filter equations enabling the use of measurements, for which the distribution of error is described by the singular precision matrix. Such a situation occurs, when the number of degrees of freedom of measuring result is less than dimensional space, in which the measurement is made. The precision matrix easily enables the description of this type of measurement, in addition estimators' formulae using the precision matrix are much more simple.

Mental fatigue in humans is a major cause of accidents in occupations requiring constant attention. The most promising indicators of fatigue are eyeblink dynamics and electroencephalography. This paper presents the results of a study aimed at establishing the dependence between eyeblink dynamics and EEG signal changes during transition to mental fatigue.

The use of Head Related Transfer Functions (HRTFs) in audio processing is a popular method of obtaining spatialized sound. HRTFs describe disturbances caused in the sound wave by the human body, especially by head and the ear pinnae. Since these shapes are unique, HRTFs differ greatly from person to person. For this reason measurement of personalized HRTFs is justified. Measured HRTFs also need further processing to be utilized in a system producing spatialized sound. This paper describes a system designed for efficient collecting of Head Related Transfer Functions as well as the measurement, interpolation and verification procedures.

In this paper it will be presented Sequential Minimal Optimization (SMO) default heuristic optimization. SMO is an algorithm for solving Support Vector Machines (SVM) problem. SMO default heuristic chooses to the active set the worst two parameters based on the Karush-Kuhn-Tucker (KKT) conditions. The proposed heuristic of alternatives chooses parameters to the active set on the basis of not only KKT conditions, but also objective function value growth. Tests show that heuristic of alternatives is generally better than SMO default heuristic.

Edge detection is one of the most important tasks in machine vision and image processing. The paper presents novel approach to construction of algorithm for detection edges in images. In order to solve the problem the concepts of the fuzzy similarity relation and homogeneity region were exploited. The results of application of the proposed edge calculation method are presented in this paper. Additionally, this paper presents an interesting artistic effect obtained by application of the image processing method based on such the detection of edges. Possible artistic effects of application of this algorithm are exemplified.

Complex algorithm for speech activity detection was presented in this article. It is based on speech enhancement, features extraction and final detection algorithm. The first one was published in ETSI standard as a module of "Advanced front-end feature extraction algorithm" in distributed speech recognition system. It consists of two main parts, noise estimatiom and Wiener filtering. For the final detection modified linear prediction coefficients and spectral entropy features are extracted form denoised signal.

This paper presents the developed model description and the calculation results of the joint influence that both rain intensity and turbulence produce on the spectrum width of the reflected signal in microwave frequency band. The model provides the possibility to calculate backscattered signal parameters at wide variety of the initial data. Then the inverse problem is considered. The results of modelling are used for the development of the signal processing algorithms to derive information on rain rate and turbulence intensity from the reflected signals.

According to the "World Report on Road Traffic Injury Prevention" jointly issued by the World Health Organization and the World Bank about 1.2 million people are killed and up to 50 million people are injured in road traffic accidents worldwide each year. While passive safety systems like the airbag are already deployed successfully to reduce fatalities and injuries, active safety systems assist the driver by issuing a warning or by taking corrective actions to either avoid a collision completely or, if impossible, to mitigate collision consequences. Today's radar sensors have the ability to detect and track objects with a high accuracy in range and velocity, therefore a collision warning system may consist of a radar sensor, a data processing unit and a model to describe possible evasion maneuvers. This allows to analyze the probability of a collision and to calculate the danger potential of the current situation. In this paper, such a system is proposed and it is verified with synthetic as well as real sensor data.

The presented paper is aimed at the area of the human emission measurement in the ELF band. It presents a designed and used aerial system suitable for the reception of ELF signals. The results of digital processing of ELF signals are presented in the contribution in a graphical form. The conclusion of the contribution deals with the possibilities of using the analysis of ELF signals for the detection of persons behind an obstacle etc.

Space-Time Adaptive Processing (STAP) is a well known technique used for dealing with clutter in order to detect moving targets. This technique was derived under assumption, that clutter has Gaussian characteristics. Unfortunately when dealing with sea clutter, Gaussian assumption is no longer valid [1]. This causes increased number of false alarms. In this paper we present improved detector to deal with non-Gaussian clutter. Detector was derived from Generalized Likelihood Ratio Test (GLRT), assuming Spherically Invariant Random Process (SIRP) as a model for the clutter. Resulting detector was named Two Dirac-Deltas (TDD) detector and it has additional parameter (Δ) in comparison to classical STAP. Based on simulations, it is shown that it is crucial to choose Δ parameter appropriately.

In navigation systems with nonlinear filtration algorithms extended Kalman filter is being used to estimate position. In this filter, the state model distribution and all relevant noise destinies are approximated by Gaussian random variable. What is more, this approach can lead to poor precision of estimation. Unscented Kalman filter UKF approximates probability distribution instead of approximating nonlinear process. The state distribution is represented by a Gaussian random variable specified using weighted sigma points, which completely capture true mean and covariance of the distribution. Another solution for the general filtering problem is to use sequential Monte Carlo methods. It is particle filtering PF based on sequential importance sampling where the samples (particles) and their weights are drawn from the posterior distribution.

The paper presents a detection performance of the LFM radar signal using the Radon transform. Such a transform extracts the line equation from the time-frequency image. The main problem which is considered in the paper is the autonomous search process of the LFM signal by the intercept receiver. It is supposed that a priori information concerning the signal duration and time delay is unknown. In this case the WVD of the signal can be splitted and performance characteristics degrade. The computer simulations are carried out for different values of the moving window width, search velocity and signal-to-noise ratio (SNR).

In this paper the analytical expression for correction on elevation angle of a radar signal is obtained. The comparison of the data of mathematical modeling with known experimental data of the same character is made.

The paper describes a possible structure of the LPI radar signal classification algorithm based on using a computer system with elements of the artificial intelligence (AI). Such an algorithm uses a combination of different signal processing tools such as the Wigner-Ville Distribution, the Wavelet Transform and the Cyclostationary Signal Analysis. The efficiency of these transformations with respect to different kinds of digital LPI radar signal modulation is considered. For a final classification and parameters extraction on the base of time-frequency or bifrequency representation the artificial intelligence methods can be used. One of the possible approaches to solving the radar signal classification problem is to use a proposed in the paper algorithm which consists of several steps: time-frequency or bifrequency transformations, a noise reduction procedure with using a two-dimensional filter, the RBF artificial neural network (NN) probability density function estimator which extracts the feature vector used for the final radar signal classification without an operator.

In this paper, the Zadeh method for the time-varying filtering of the non-stationary radar signal, embedded in non-Gaussian disturbances, has been considered analytically and numerically. The non-stationary radar signal has been received from a real radar receiver and only a real realisation has been accessible for experiments. The additive noise signal with Weibull distribution, as an example of non-Gaussian disturbances, has been taken into account. The linear, time-varying (LTV) Zadeh filter, for suppressing the noise signal and passing the radar signal, has been developed based on the concept of the Weyl symbol. The Weyl symbol, or equivalently the indicator function, has been designed from the Short Time Fourier Transform (STFT) as the time-frequency (TF) representation of a noisy signal. Comprehensive numerical experiments illustrate the results of the filtering process.

This article is focused on the design of the modern digital ELINT receiver. This digital ELINT receiver must be able to process the radar CW and pulse signals in intermediate frequency band 625 - 875 MHz with dynamic range 120dB. These strict requirements on the parameters of receiver ask for the not conventional solution of the receiver structure. Whole receiver is designed as the set of subblocks that are performed partial tasks of signal processing. For example, the receiver contains the wideband receiver, noise receiver and several narrow receivers. The extra attention is paid both the choosing of the suitable A/D convertors and the methods of real-time signal processing in this article. This paper describes the block diagram of the digital ELINT receiver and its operation when the typically radar signal are received and processed. The example of the functional block diagram of this receiver is included.

According to the extreme value theory, the tail distribution of virtually any statistical distribution can be uniquely modeled by the generalized Pareto distribution. Based on this property it is possible to approximate the tail of the radar clutter distribution and develop a distribution-independent CFAR detector. In the paper the multiplicative clutter model is considered. Correlated clutter intensity with exponential, G⁰₁ and K_I distribution is simulated. The correlation is introduced by lowpass filtering of the clutter speckle component. It is showed using the chi-square goodness-of-fit test that the tail of the correlated clutter can be well approximated by the generalized Pareto distribution.

The paper under consideration is actually an attempt to theoretically prove the possibility of creation of a sequential nanolithography method with ultimate parameters by using liquid nanojets from reactive elements in order to put the nanotechnology methods on a solid commercial basis. Detection of secondary radiation forming on the contact place of jet and target enables to use the device as scanning microscope.

Microwave frequency discriminator (MFD) is a device, which is used to generate signal carrying information about frequency of input signal. Depending on type of subassemblies, which were used in examined MFD, its parameters will change. Developed simulator BP-PK-V2.0 is able to measure frequency of virtual or obtained from measurement by other microwave devices signals. Its most important feature is, that the program enables its user to test parameters of discriminator created from certain subassemblies without manufacturing physical device and, when the results are not satisfactory, remodeling its structure with one or more elements. Tests will end when expected performance is achieved and only then should simulated MFD be implemented in PCB. Two types of visualization, in which described simulator is equipped with, enable to determine properties of two methods of estimating measured value: continuous method (with high resolution) and discrete method, in which information precision is limited to subrange with finite width.

Modern state-of-the art watermarking systems use precise algorithms for ensure perceptual transparency of the additional signal in the host signal presence. Various Human Auditory System (HAS) models are implemented but only few of them are computationally effective giving reliable acoustic masking effect. This paper presents efficient algorithm and its implementation for Just Noticeable Difference level estimation using HAS for data hiding application. Implementation is based on effective Johnston [1] HAS model and real-time processing using TMS 320C6713 DSK board. The results of implementation as well as subjective fidelity test using standard ITU-R BS 1116.1 are described and illustrated. Numerical results of DSP real-time implementation are compared with the Matlab off-line HAS computational model.

Drift Scanner Method is very effective procedure used to reduce the phase drift effect in the radio links. The effect "out of tuned" signal in the basic frequency band is a result of small, long term stability codec's clocks both at the transmitter and receiver's side as well as small stability of HF or VHF carrier frequency in the standard modulators and demodulators in the radio transceiver configuration. The paper presents experimental results carried out in the radio links with applied procedure of reducing total output phase drift (ppm value) by using Phase Drift Scanner method. Described method is also useful in watermarking applications.

The presented contribution is focused on the field of alternative use of seismic and magnetic sensors in an urbanized environment. The first part of the contribution presents the results achieved in the development of these sensors. Both theoretical possibilities and practical results of developed sensors are analyzed here and supplemented with their photographs. The next part of the contribution deals with the design of communication between individual sensors applying the principles of C4ISR in the conditions of an urbanized environment and the proposal of the own/foreign persons identification concept in the conditions of an urbanized environment.

Most of the Radio Frequency Identification (RFID) systems operating in HF and UHF bands employ narrowband modulations (FSK or ASK) with Manchester coding. However, these simple transmission schemes are vulnerable to narrowband interference (NBI) generated by other radio systems working in the same frequency band, and also suffer from collision problem and need special anti-collision procedures. This becomes especially important when operating in a noisy, crowded industrial environment. In this paper we show the performance of RFID system with DS-CDMA transmission in comparison to a standard system with FSK modulation defined in ISO 18000-7. Our simulation results show that without any bandwidth expansion the immunity against NBI can be improved by 8 dB and the system capacity can be 7 times higher when using DS-CDMA transmission instead of FSK modulation with Manchester coding.

In this paper we present the radio signal acquisition module designed and build in our team for Software Radio and RADAR experiments. The module allows sampling RF and IF signals from two sources and to transfer acquired data to a Personal Computer via USB 2.0 interface. Thanks to built-in FPGA chip, it is possible to perform on-board signal preprocessing before transferring the data to PC. The PC is responsible for module configuration, triggering and data storage. We present the preliminary performance results obtained in practical experiments and measurements. The example application in Passive Coherent Location (PCL) experiments is also described.

The measurement technologies developed in the Institute of Applied Optics (INOS) are presented. The examples of optical technology applied in measurement systems are described.

Lens systems designed to work like axicons can be a simple and cheap way of generating focal lines characteristic for these elements. We present two lens axicons made from ordinary lenses with spherical surfaces which take advantage of their inherent spherical aberration for creation of the focal segment. One of them is composed from two lenses with blocked central part. The second one is a single meniscus lens with appropriate reflective coatings. The results show that both new elements exhibit main axicon properties. Additionally the second lens axicon is resistant to astigmatism and maintains good quality of the focal segment even in the case of oblique illumination.

The Scanning Helium Microscopy is a new technique currently under development. The paper is an overview of measurements of the geometrical characteristics of Silicon wafer concentrating on accuracy and closely related matters. In the microscope the helium atom beam is used as a probe. The overall microscope resolution depends on a deflecting element, which shapes the beam and focuses it onto a sample's surface. The most promising focusing component appears to be an ultra thin silicon wafer that is deformed under a precise electric field. Flatness and thickness uniformity of the wafer must be measured in order to select the best plate to be used in the microscope. A scanning measurement system consists of two coaxially positioned confocal heads. The paper discusses measures taken to overcome the system sensitivity to temperature variation and concludes with utilizing symmetry descriptors for final selection of wafers.

A method of measurement of gradient-index elements is presented. Two glasses for GRIN elements and equipment for experiments of diffusion are presented.

The spectral properties of the plane grating with 1300 lines/mm mounted at PGS-2 spectrograph constructed by Carl Zeiss GmbH were investigated. We elaborated the adjustable parameters for this grating and also we made some analysis of the matching for standard monochromator with our grating at PGS-2 spectrograph.

This paper presents investigations of signal processing algorithms used in FSCW systems for reflection source range estimation in different transmission channels. The three algorithms: IDFT, enumeration and G. Ybarra have been tested. Obtained results of simulations and measurements are compared and discussed.

The linearization of non-linear state equation is based on replacement of non-linear equation by its linear approximation. The main aim of linearization is to make the linear approach a good approximation of the non-linear equation in the whole state space and for time t approaching infinity. The optimal linearization method (OLM) is based on such a choice of linear approximation matrix that the mean-square error of the difference between the non-linear model and its linear approximation is minimal. In the paper the algorithm of OLM method and its implementation in computer program will be presented. The program computes elements of optimal matrices on the basis of non-linear state equation and its linear approximation.

In presented paper the selected aspects of the global linearization of non-linear state are considered. The choice of the way of changing of the state variables in this method has a particular meaning for the complexity of obtained linear model, therefore for the costs of calculation process. Considerations are illustrated by the example of non-linear model of electrical circuit.

The non-stationary temperature distribution in a 2-D cross-section of a cylindrical copper wire with insulation was investigated. The wire was conducting direct current of a constant value. The Hankel boundary condition modelling convectional cooling was applied. The convective heat transfer coefficient was assumed to be a function of the angle coordinate in the cylindrical coordinate system. The heat transfer equation was discretized in space and time domain with the use of the implicit FDM. For each discrete value in the time domain the solution of the resulted system of algebraic equations was determined by a parallel conjugate gradient method. The results of the simulation were compared to those obtained from a commercial software package: EMRC Nisa. The comparison showed good agreement between the results. All the results and the comparison are presented in the paper along with the comments and conclusions.

A four-terminal (4T) bridge-circuit unconventionally supplied by two current sources connected in parallel to opposite arms, named double current bridge (2J) has been presented. This circuit has been applied for experimental stress analysis and worked with constantan foil strain gauges placed upon a beam. Some results of the measurements done with two-active-gauge bridge and four-active-gauge bridge have been described. Some advantages of these bridge-circuit, which could be used to the data acquisition during experimental measurements of a stress in a cantilever beam and a simply supported beam have been mentioned.

In the article, results of simulation and laboratory research of designed voltage transformer are described. In the first part of the paper voltage transformer model is presented. Second part of the article is dedicated to voltage transformer model errors simulation. In the last section of this paper verification of simulation results is described. Correct simulation of the voltage transformer enables shorten design time and reduction of cost production.

This PDF file contains the front matter for volume 6937, including the Title Page, Copyright information, Table of Contents, Introduction, and the Conference Committee listing.