Notions of the externally and internally positive standard and singular discrete-time and continuous-time linear systems are introduced. Necessary and sufficient conditions for the external and internal positivity of linear systems are given. It is shown that the reachability and controllability of the internally positive linear systems are not invariant under the state-feedbacks. By suitable choice of the state-feedbacks an unreachable internally positive linear systems can be made reachable and a controllable internally positive system can be made uncontrollable. The basic properties of continuous-time and discrete-time linear compartmental systems are derived and the relationships between the compartmental and positive systems are established. The realization problem for compartmental systems is formulated and partly solved.

The subject of the paper is the immediate and not so immediate future of the DWDM systems using direct TDM multiplexing for the individual wavelength channels. The following problems and questions have been tried to be addressed: a balance and competition between the electronic and optical bandwidths in WDM systems, importance of this competition now and in the future, major factors contributing to this competition, costs of the fast and dense WDM systems, the most important price generating factors in the WDM systems, etc. Some of the answers to these questions are very probably the following: now the best WDM systems work with spectral efficiencies of 0.2 bit/s/Hz for the trunk communications system solutions (5 THz of aggregated bandwidth) and well below 0.1 bit/s/Hz for the local communications; in the nearest decade the spectral efficiency of the WDM overcomes 0.5 bit/s/Hz and 50THz of the aggregated bandwidth (ten times the aggregated bandwidth used today).

In modern telecommunication systems data are transmitted over long distances at high transmission rates. Such systems require high-speed, all-optical 3R regeneration (reamplifying, reshaping, retiming) of transmitting signal. In this article are reviewed telecommunication systems in aspects of 3R regeneration. In common use are classical systems that amplify light with Erbium Doped or Raman fibers and reshape/retime signal in electronic way. Novel all optical 3R regeneration systems without optics-electronics conversion are also described.

In this paper, we are proposing more efficient one-step negabinary signed-digit algorithms for the addition/subtraction operations. It is shown that by using digits grouping of the negabinary signed-digits, a huge reduction of the number of the symbolic substitution computation rules involved in the arithmetic computations will be achieved. Further, to increase the information storage density, one-step trinary negabinary (using base = -3) and negabinary quaternary (using base = -4) signed-digit will be proposed. The proposed algorithms are very suitable for optical implementation. Various holographic and nonholographic methods based on symbolic substitution content addressable memory (CAM) are suggested for optoelectronic implementation. Among them, the method of joint spatial encoding technique and incoherent optical correlator to act as as shared CAM will be presented.

In order to verify the accuracy of the analytical framework, we performed a simulation study of the call blocking performance in ring networks of different sizes. Each data point in the simulation was obtained using 10⁶ calls arriving at the given node. During the process, we simulated the no-converter (q = O) and full-converter (q = 1) cases and obtained the blocking probability was then compared with the analytical results, obtained from literature.

The technology of superconducting cavities has developed rapidly during the past decade and gradients of 25 MV/m at an unloaded Q of 1e10 can be guaranteed for a large scale production as required for the X-FEL with its 1000 cavities. The rf control of the cavity fields to the level of 10e-4 for amplitude and 0.1 deg. for phase however presents a significant technical challenge due the narrow bandwidth of the cavities which results in a high sensitivity to perturbations of the resonance frequency by mechanical vibrations (microphonics) and Lorentz force detuning. A digital rf control system has been developed for the UV-FEL presently under construction at DESY which will demonstrate the required control performance while providing flexibility in the control algorithms, precise calibration of the vector-sum, and extensive diagnostics and exception handling capabilities. A piezotranslator based active compensation scheme for the time varying Lorentz force detuning will reduce significantly reduce the rf power required for control.

The cavity control system for the TESLA -- TeV-Energy Superconducting Linear Accelerator project is initially introduced. The elementary analysis of the cavity resonator on RF (radio frequency) level and low level frequency with signal and power considerations is presented. For the field vector detection the digital signal processing is proposed. The electromechanical model concerning Lorentz force detuning is applied for analyzing the basic features of the system performance. For multiple cavities driven by one klystron the field vector sum control is considered. Simulink model implementation is developed to explore the feedback and feed-forward system operation and some experimental results for signals and power considerations are presented.

The cavity control system for the TESLA -- TeV-Energy Superconducting Linear Accelerator project is initially introduced in this paper. The FPGA -- Field Programmable Gate Array technology has been implemented for digital controller stabilizing cavity field gradient. The cavity SIMULINK model has been applied to test the hardware controller. The step operation method has been developed for testing the FPGA device coupled to the SIMULINK model of the analog real plant. The FPGA signal processing has been verified according to the required algorithm of the reference MATLAB controller. Some experimental results have been presented for different cavity operational conditions.

The paper is an introduction to the optimization methods of the linear accelerator cavity control system. Three distinct time periods of cavity operation are considered; filling with the EM field energy, field stabilization, and field decay. These periods represent completely different states and behavior of the cavity. The cavity could be operated by several different methods in each work phase: During the filling -- feedback and feed-forward alone, feedback and feed-forward together, self-tuning; During the flattop -- feed-forward and feedback alone or together, During the decay -- detuning and quality factor may be measured. The optimization is understood as a choice of the most efficient way of the cavity control during each period. The control may be done in terms of minimum power consumption from the klystron during whole work cycle and efficient field stabilization in the cavity, during flattop period. The introductory analysis of the cavity operational modes in three mentioned periods is presented in this paper. Additionally the alternative more precise algorithm of the cavity voltage envelope detection is proposed.

The cavity resonator modeling for the TESLA -- TeV-Energy Superconducting Linear Accelerator project is initially introduced. The electromechanical model including Lorentz force detuning and beam loading is applied for analyzing the basic features of the plant. The continuous SIMULINK and digital MATLAB model implementation is developed as a reference for the hardware simulator based on the FPGA -- Field Programmable Gate Array technology. The step operation mode has been applied for testing of the FPGA device coupled to the software control block. The FPGA signal processing has been verified according to the desired model of the real cavity plant. The numerical aspects have been investigated for the efficient design. Some experimental results have been presented for different cavity operational conditions. The following considerations have lead to the synthesis of the efficient algorithm for the cavity model, then implemented in the FPGA system.

The paper contains the analysis of the application possibilities offered by the new generation of the FPGA chips. The new generation of the FPGA chips contain DSP blocks. The new functionalities are well suited for the application in the TESLA LLRF cavity simulation and control system (SIMCON). A debate on the programming methods of the new chips and the algorithm parameterization was presented. The aim of the, FPGA chip based, system analysis is the optimal chip usage to increase the maximum frequency at which the system can work efficiently, and the optimal usage of the accessible chip resources (DSP blocks). The exemplary results for a few practical calculated implementations were presented and analyzed. The implementations included some basic DSP operations performed in the FPGA chips of Altera and Xilinx. There were compared the results for a few different chips. The TESLA superconducting cavity simulator was efficiently implemented. The results were presented for the first time, for the pure FPGA/VHDL solution. The realization costs were debated in the dependence of given system parameters and the applied type of the FPGA chip.

This paper presents a FPGA based DSP system for realtime simulation of superconducting accelerator's cavity. The superconducting linacs require sophisticated control systems for maintaining the constant amplitude and phase of accelerating field in the accelerator's cavities. The debugging of these systems on real hardware can be both difficult and dangerous. To allow testing of the real LLRF systems in the real time and with different cavity parameters, the FPGA based system has been developed.

The RF Phase Reference Distribution System (PRDS) must deliver a highly RF phase stable signal to many various RF subsystems of the X-ray Free Electron Laser (XFEL) and in the future the TESLA linear collider. The required phase synchronization corresponding to the short term stability of 1 ps must be guaranteed. Taking into consideration large amount of devices to be synchronized, long distances and necessity of delivering different frequencies, the design of PRDS becomes a very difficult and challenging task. This paper describes the main considered issues. Such parameters as distribution frequency, waveguide attenuation, multiplier noise and temperature influence on the system are taken into account. The advantages and disadvantages of coaxial cables and optical fiber as the distribution medium are compared. The feedback system stabilizing long term phase drifts is presented and the structure of PRDS which may fulfill the design requirements is proposed.

A concise overview of the laboratory solution of the FPGA based TESLA cavity simulator and controller (SIMCON) is presented. The major emphasis is put in this paper on the high level part of the system. There were described the following steps of the system design and realization: solution choice, design of system components, implementing the solutions, introduction of the application, initial analysis of the working application. The paper is a first description of the working DOOCS server for the FPGA based TESLA cavity SIMCON (which is a part of the LLRF subsystem). The data gathered from the work of the DOOCS server promise for the system optimization possibilities. The server will be supplemented with the GUI in the next step of this effort. Throughout the work we will refer to the debated system as to the TESLA SIMCON DOOCS server or in short the "simcon server." The hardware layer of the TESLA cavity SIMCON (to which the designed software refers to) was realized in a single FPGA Virtex chip by Xilinx (XC2V3000 development board by Nallatech).

This paper describes an alternative approach for control and data acquisition system to be used in TESLA controller and simulator (SIMCON) boards. The standard VME controller may be replaced with a cheap embedded PC to provide equivalent or even superior functionality. The new approach offers better cost/performance ratio, better scalability of the system and better testability of the SIMCON boards.

New hardware and software developments on the Backing Calorimeter (BAC) for the ZEUS detector are presented. The modernization of the detector was related to the recent luminosity upgrade of the HERA accelerator. The role and place of the BAC detector in the ZEUS experiment is described with special emphasis on the new BAC muon trigger and its diagnostic and monitoring system. This overview introduces a series of detailed articles following in this chapter of the SPIE proceedings.

First Level Trigger (FLT) of the Backing Calorimeter (BAC) for the ZEUS experiment is presented. The Backing Calorimeter was designed to measure the energy of particles which are not absorbed in Central Uranium Calorimeter and to identify muons. Its trigger system calculates the total energy (E), transverse energy (E_t), two highest energy deposits measured in the detector (E₁,E₂) and provides the position of muons passing through the detector (muon bits).

The paper describes design and construction of hardware diagnostics layer dedicated to the local trigger of the Backing Calorimeter (BAC). The BAC is a part of the ZEUS experiment in DESY, Hamburg. A general characteristic of the hardware of BAC trigger was presented. The design of hardware diagnostic and calibration sub-systems for BAC trigger bases on the continuous monitoring of consecutive electronic and photonic blocks. The monitoring process is performed via the specialized tests. The standardized diagnostic components were realized in the algorithmic and parameterized description in AHDL. There were presented the implementation results in ALTERA ACEX chips.

One of the most important aims of the BAC diagnostic system is to provide high reliability of the detector. Part of this task is to minimize noises in the position readout and to find optimal thresholds for comparators. Presented paper describes the method of handling this complex problem. In addition collecting a high statistic sample of muon tracks in the clean environment allows to verify the data base describing the mapping of readout channels onto the detector geometry.

The idea and realization of data presentation system is described in this paper. Data is received from the diagnostic system of the BAC detector. The presented system is a part of the DQMS (Data Quality Monitoring and Management). The system enables graphical presentation of the location of electronic blocks. It is possible to indicate the links between these blocks, and the actual state of the specified components. The aim to build this system was to assure the proper working of the BAC detector, and in the case of detecting abnormalities to find them out as soon as possible, detect the place of the error and the causes of the failure. The presented software helps to find the errors and is a sort of knowledge compendium about the BAC detector (its equipment, links structure, etc.). The engineering of the visualization system as well as functional tasks were described, and the discussion of the results was made. Some examples, showing the usage of the system, and the received results of its work were presented.

This work describes a design and development of the Internet system for the data quality monitoring during the Backing Calorimeter (BAC) operation in the ZEUS experiment and for the archive data analysis. The development includes functional data base system application, data interaction processes and the web interface, built using PHP scripts and JAVA applets. The system implementation process, in ZEUS experiment, was described and its performance results were presented, based on the selected examples.

The algorithm for a L1 muon trigger based on six RPC planes is described. Single muon L1 rates and efficiencies are presented. Simulations of L1 RPC Trigger rates from prompt muons, RPC noise and neutron background are shown. The 6 planes algorithm leads to large reduction of false triggers originating from ghosts and uncorrelated background.

The paper describes a behavioral model of fast, pipeline sorter dedicated to electronic triggering applications in the experiments of high energy physics (HEP). The sorter was implemented in FPGA for the RPC Muon Detector of CMS experiment (LHC accelerator, CERN) and for Backing Calorimeter (BAC) in ZEUS experiment (HERA accelerator, DESY). A general principle of the applied sorting algorithm was presented. The implementation results were debated in detail for chosen FPGA chips by ALTERA and XILINX manufactures. The realization costs have been calculated as function of system parameters.

Proton-proton collisions in the LHC accelerator will occur every 25 ns. The muon trigger of the CMS experiment will have to analyze data from 200 000 channels of RPC chambers every bunch crossing. Special compression algorithm has been developed to transmit the data from the chambers to the trigger electronics through optical fibers. The data flow has been simulated, and the data loss estimate is presented.

The results of proton radiation test of electronic devices for RPC trigger electronic system of CMS detector are presented. For Xilinx Spartan-IIE FPGA the cross section for Single Event Upsets (SEUs) in configuration bits was measured. The dynamic SEUs in flip-flops was also investigated, but not observed. For the FLASH memories no single upsets were detected, but after a huge dose permanent damages of devices were observed. For SDRAM memories, the SEU cross section was measured. A brief description of radiation inducted effects in FPGAs, SRAM and FLASH memories is also presented.

The paper describes design and practical realization of an internal communication layer referred to as the Internal Interface (II). The system was realized for the RPC Muon Trigger of the CMS experiment. Fully automatic implementation of the communication layer is realized in the FPGA chips and in the control software. The methodology of implementation was presented in the description form of the interface structure from the sides of hardware and software. The examples of the communication layer realizations were given for the RPC Muon Trigger.

Perhaps the most powerful cosmic processes ever observed are gamma ray bursts (GRB). So far, phenomena responsible for GRB have not been unambiguously identified. In the present paper we propose an approach completely different from the classical one. It employs experimental techniques developed for particle physics. Presented project is pioneering research in the unexplored so far domain of cosmic phenomena on the time scale of seconds. Both the rate of signal in question and the rate of unexpected background are not known. Therefore we decided to divide the project into two phases: phase I -- two CCD cameras, phase II - a system of cameras covering all sky. The phase I is well defined whereas detailed realization of phase II will depend strongly on results and experience gained in phase I.

We present optimized performance of algorithms developed for detection of point like, visible light bursts in the sky. The algorithms based on analysis of series of consequtive images and detecting local differences between them were tested on simulated data obtained by inserting images of stars of different magnitudes at random positions. We discuss the choice of parameters which results in the maximal detection efficiency and simultaneously keeps the number of false detections as low as possible.

Nowadays less and less students choose science as their favorite subjects. The main reason is probably lack of interesting and not too difficult methods and exercises which would allow them to be in touch with modern ideas of chemistry, physics and math. One of the ways to raise students' interest in science is to give them first-hand acquaintance with astronomy. In this paper we discuss experience from a high-school praxis gathered with a low-cost system based on a webcam and simple optics.

An automatic system for simple astronomical measurements is proposed. It consists of a CCD based webcam, standard photo-lenses and rotating mount with a computer driven step motor. The system is controlled by dedicated user friendly software with an intuitive graphical user interface. It is demonstrated how it can be used to measure light curves of variable stars. The cost of the system is below $200 and it is well suitable for education or for hobby.

The SkyEye project is an attempt to create software for educational and amateur variable stars research. Easy graphical interface, automation of many actions and possibility of using low-cost internet cameras makes this software suitable for students and amateur astronomers for observations, measurements and data analysis. The goal is achieved by extending AudeLa project with additional shared libraries written in C/C++ and TCL scripts, much effort was made in order to ensure compatibility with different operating systems, Linux and Windows. The project was developed in the framework of the "Pi of the Sky" collaboration.

In this paper new designs of modern optoelectronics devices based on GaN-type materials are presented. First, fundamental properties of gallium nitrides are presented, with special attention paid to its optical characteristics. Then examples of devices fabricated at Wroclaw University of Technology are shown, namely MSM detectors based on AlGaN. A short literature overview of devices based on gallium nitride compounds is also given. Presented applications include DFB lasers, structure, LED, optical waveguides, photonic crystals and light modulators made of GaN compounds.

This paper presents a Q-switched Er:YAG laser generating in near infrared range. In this laser system Pockels cell (as an active switch) was applied. For the optimal repetition rate of 10 Hz and maximal pumping energy of 62 J over 15 mJ of the ouptut laser energy was achieved. The pulses generated were characterized by time duration of 115 ns corresponding with 130 kW peak power. Non-linear absorbers allowing to build an effective losses modulator are also discussed.

In the paper, results of observations concerned Raman scattering in Zn_1-xBe_xSe semiconductor mixed crystals are presented. Measurements of Zn_1-xBe_xSe mixed crystals were made for temperatures 292K, 225K, 150K and 77K with Be content included in the range 0 < x < 0.25. From the polarized Raman spectra, the longitudinal optical (LO) and transverse optical (TO) modes that correspond to ZnSe-, BeSe-like single crystals, are distinguished. Theoretical calculations of the frequencies of the ZnSe-, BeSe-like modes of Zn_1-xBe_xSe semiconductor mixed crystals were performed using MREI model (Modified Random Element Isodisplacement). Furthermore, the optical modes of Zn_1-xBe_xSe were compared for different concentrations of Be.

The perturbation phenomena in CO molecule were investigated by many authors. These perturbations in the rotational structure of CO spectra are attributed to several electronics molecular states acting on A¹π state according with Kronig's selection rules. An occurrence of the perturbation in the band origins with the vibrational level of v' = 6 for ¹³CO molecule is a subject of our analysis here. The considerations are performed on the basis of an analysis of IV-th positive system in ¹³CO molecule.

Here we present the application of mechanical spectroscopy for a registration the free vibration occurring in quartz filament. The harmonic vibrations were observed by laser beam diffraction technique. Numerical analysis was performed on the basis of least square routine. Finally we received logarithmic decrement, a resonant frequency and Young's modulus.

We present and compare two numerical approaches to analysis of photonic crystal fibers, i.e., finite element method based on triangular elements and Fourier decomposition method. The two methods were employed to determine propagation constants in hexagonal photonic fiber by solving vectorial and scalar wave equations. The results obtained with different methods shows very good agreement. We also demonstrated that coupling coefficients between orthogonally polarized modes in fully vector wave equation are negligible for this type of structure and for this reason they can be disregarded. Such a simplification saves computational time and hardware resources without loosing the precision of calculations. We also compared the efficiency of scalar and vectorial approach in calculations of cut-off wavelength. Our results show that scalar approach is not accurate enough for modeling fibers with large filling factor.

We measured polarimetric sensitivity of a three-mode elliptical-core fiber to strain for all spatial modes. Phase and group modal birefringence were also determined for all modes to fully characterize the investigated fiber. Experimental results show a very high difference in fiber sensitivity to strain versus mode order. It changes the sign from negative for E₁₁ mode to positive for E₃₁ mode. This effect can be potentially employed in polarimetric strain sensors. We also modeled all measured parameters using Optiwave BPM-Cad and Cosmos/M software packages. The measured values of phase and group modal birefringence agree well with those obtained from calculations for all spatial modes. Unfortunately, we observed poor agreement between experimental and calculated values of strain sensitivity, which is most probably caused by the lack of reliable material constants for SiO₂/GeO₂ glasses.

Polarization mode dispersion (PMD) is a major limitation in optical fiber transmission systems. The paper presents a new method of PMD compensation based on the use of highly birefringent (HB) bow-tie fibers. The method relies on the application of dynamically induced longitudinal strain that modifies differential group delay (DGD) responsible for effective PMD compensation.

Polarization-maintaining highly birefringent (HB) photonic crystal fibers (PCFs) are a completely new range of optical fibers potentially offering new polarization properties and possibilities. In this paper, we discuss polarization properties of HB PCFs and present initial experimental data. A novel experimental method has been adapted for beat length measurement in various HB fibers.

Problems related to optical activation of high-power fiber lasers are presented in this work. Double-clad fiber lasers with different cross sections of inner clad are discussed. The authors of this study have presented an alternative attempt at analyzing the problems touched upon. In this paper a computer program allowing visualization of the path of the light rays in geometrical optics approximation is presented. This program visualizes a trajectory of the light rays along the fiber and the result is the graphic presentation of distribution of radiation transmitted along the fiber (on cutting plane of the fiber). Circle, stadium and D-shaped clads were considered. The results of the analyses carried out clearly indicate unquestionable superiority of D-shaped and stadium-shaped fibers over fibers with circular cross section, when the efficiency of activation is taken into account.

Broadband fiber ASE light test source in third transmission window designated for high spectral resolution Bragg gratings measurements was realized. It was achieved by the use of erbium doped fiber in the ring laser configuration with the beam splitter made in fused taper technology. The fiber and EDFA properties were measured to optimize the fiber length for maximum amplification. System was pumped by 110 mW 980 nm laser diode. The measured ASE output power was 12 dB better than in the reference SLED source in 1520- 1550 nm range.

In this paper high power Yb-doped double-clad fiber laser is presented. A Yb³⁺-silica fiber laser has been cladding pumped at 937 nm by a InGaAs semiconductor laser diode and operated with the slope efficiency of 73 ± 3% with respect to the incident pump power. We obtained 4 W cw-output power when working with 20-m long fiber with laser core in 7 μm diameter (cut-off wavelength - 1 μm) and pump core in 120 x 120 μm (rectangle-shaped, NA = 0.6). Yb-doping concentration has been at the level 3 - 10 • 10¹⁹ cm^-3 and attenuation in laser core has been 8 - 12 dB/km. The fiber laser operated at 1084 nm.

In this paper a high-power Nd-doped double-clad fiber laser is presented. We obtained 10 W cw-output power from 20 m long fiber with laser core in 12 μm diameter (NA = 0.12) and pump core in 400 μm diameter (D-shaped, NA = 0.38). Nd-doping concentration has been at 1300 ppm level and attenuation in the laser core has been less than 10 dB/km (for λ = 1100 nm). High power diode laser module operating at λ = 808 nm has been used as a pump unit. This pump ensured 30 W cw output power. As a result, we have built a coherent source of radiation generating 10 W cw output power with 63 percent slope efficiency.

In this article we present a diode pumped fiber laser. An active Q-switched fiber laser system has been elaborated. An active neodymium-doped double-clad optical fiber was used as an active medium. For low repetition rate (20 Hz) we achieved pulses with 211 ns time duration and 12 μJ energy. Applying high repetition (10 kHz) driver of Pockels cell we achieved pulses with 250 ns time duration and 300 μJ energy (for 500 Hz repetition rate). The length of the active fiber was 5 m. The pump source delivered 30 W continuous output power at 808 nm wavelength.

This paper presents controlling-measuring buses (linear and quasi-linear) using amplitude properties of fiber-optics and fiber-optical sensors of typical and/or special construction. It refers to linear sensors and commonly used measuring OTDR method, as wel as to realizations with linear binary sensors in transmission networks. Presented advantages and parameters of such measuring structures. Presented main area of application buses and practical realizations, regarding typical needs in industrial measurements, points out technical and economical advantages, in opposition to difficult and expensive (but more accurate) technology of measuring networks based on polarization and interfering methods.

Generally, the seismic waves appear during the earthquake are bulk longitudinal or transverse type waves. However, the last developed theory shown that so called seismic rotation waves exist, also. These waves appear in the case of non-ideal elasticity due to defect content in a mdeium or due to internal structure of the medium. The detection such kind of waves should use new techniques because conventional seismographs are inertial sensors for linear acceleration, only. Form this reason the Fiber-Optic Rotational Seismometer (FORS) based on the fiber-optic Sagnac interferometer is proposed. The main advantage of such system is measurement of absolute rotation around any axis perpendicular to the optical path plane and without sensitivity to uniform linear motion or distortion. In the article system FORS-II currently developing is presented. This system using appropriate system configuration has extremely high sensitivity without characteristic for the fiber-optic gyro sensitive on polarization phenomenon.

The main technical parameters characterize work of optical fiber sensors for detection in real time polarization parameters of light are investigated in this paper. Generally, parameter defined as precision is used for comparison two in-line fiber-optic polarization analyzers where one used polarimetric and second interferometric sensor configuration. The theoretical description of those systems uses the coherence matrix and the Jones matrix calculus approach for partially polarized light source and fiber-optic elements, respectively. Such theoretical analyze permits obtaining analytical relations for polarization parameters based on measuring of electrical quantities. These relations were principle for describing theoretical measurement error. The experimental results obtained from testing of laboratory analyzer models had been used for definition of fundamental system parameter named system device precision, which uses statistical model. Results of these analyses showed that interferometric system allows more precise determination of the state of polarization in shorter measurement time. The polarimetric system gave worst precision what was caused mainly by temperature instabilities during adjusting procedure. However precision of both systems are better than in a bulk-optic anlayzers.

We describe a cost-effective fiber optic bend sensor that utilizes changes in optical intensity as the detected parameter. This sensor is envisaged for application in measurements of rail bends in order to identify different moving objects.

Influence of laser spectra on a fiber optic Michelson interferometer's contrast is mathematically described and simulated. Proposal of using contrast-based setup as elongation meter as well as method of measuring range increasing and algorithm for signal processing is also presented. Experimental setup and software were worked out. We obtained 5-mm measuring range, where the biggest difference between real and measured elongation is 25 μm.

Burning pulverized coal in power boilers causes considerable emission of atmospheric pollution. In order to decrease it the combustion process itself has been modified, however at cost of side effects like: increased level of unburned coal particles in the ashes. There are tens of burners in a single power boiler and emission level measurements are made in flue gas duct, so the control based on such averaged and heavily delayed values often results ineffective. The neural controller of the pulverized coal burner attempts to resolve these problems. The clue is utilization of fiber-optic system for monitoring of chosen zone of flame developed in Department of Electronics of Technical University of Lublin. The article contains description of controlled system and optical fiber measurement system, an idea of the controller as well as some results obtained for experimental burner.

A non-invasive single-channel SQUID magnetometer for fetal magnetocardiography has been developed. The signal is picked-up with a wire wound third order gradiometer. The optimal configuration of the flux transformer is a trade-off between sufficient sensitivity for the magnetic field originated in fetal heart and effective immunity against the ambient magnetic noise. The over all system performance together with the measuring probe and SQUID electronics is described. The balancing of the third order flux transformer is discussed as well as the signal processing of fetal magnetocardiogram recordings.

The effect of quasi-monochromatic partially coherent illumination in the lensless Fresnel holography is studied theoretically, based on the coherence theory. The solution generality is restricted to the analyzed class of the stationary object illumination. A simple solution to the problem basing on linear system theory is given. The results and simulations are discussed in the context of holographic fringe bandwidth with accordance device. Both in line and off-axis holographic setups are analyzed.

This paper reports problems occurring during recording and reconstruction of Fourier transform holograms formed in LiNbO₃:Fe. We will consider how the choice of crystal, the usage of phase masks and application of different wavelengths influences the recording process.

The paper presents review of the selected joined transform correlators (JTC) used for automatic images recognition. Because they are used in non-contact optical measurement systems thus special numerical processing should be used for anlaysis of data collected by them. The neutral network approach, wide development in last decade for such system, seems to be small useful, mainly because it creates computing model. The image is parallel information and such method as the Fourier transform are more useful for its processing. From this reason the wavelet transform as generalization of the Fourier method has been chosen as optimal. On this base the JTC uses wavelet transforms (WT) for analysis because it is a powerful tool for wavelet filtration, image feature extraction and recognition of rationally distorted images. The laboratory system uses the joint wavelet transform correlator (JWTC) and its possibilities were presented on this paper as final result of review.

Wavelet transform method is developed independently in the fields of mathematics, quantum physics, electrical engineering, and seismic geology from a several decades. The wavelets are mathematical functions that cut up data into different frequency components, and then study each component with a resolution matched to its scale. This method is more useful than traditional Fourier methods, when the signal contains discontinuities and sharp spikes. Interactions between different scientific fields have led to many new wavelet applications such as image compression, turbulence, human vision, radar, and earthquake prediction. This paper is dedicated to possibility of using the wavelet transform in some optical research method i.e. interference images analysis. Special attention is paid to noise detection in these images.

The scope of this work is to develop a miniature digital holographic interferometry (DHI) system enabling remote measurements of shape and deformation of small 3D objects. Due to the use of digital holography the system does not require holographic plates but uses a simple digital camera for recording of holograms. Object intensity and phase is reconstructed numerically by Fresnel approach and can be applied for monitoring of object changes. In the paper the variety of systems described in literature are presented and analyzed. The configuration of novel digital holographic interferometer is described and the phase analysis method and scaling algorithms are presented. The initial experimental results obtained by means of DHI demonstrator are presented for the case of a small active micro membrane testing. The error analysis and further suggestions toward design of the final version of DHI system are given.

The paper describes the optical properties of the selected diffractive elements being promising for imaging with extended depth of focus. According to the results of our previous investigations, diffractive versions of the axicon and the light sword optical element were chosen for an analysis. Particularly we have examined the point spread functions of the above elements. The investigated optical properties of the selected diffractive structures were compared with the analogous properties of the conventional Fresnel lens. The results of the numerical simulations were verified experimentally in the optical set-up.

A new numerical algorithm for light propagation simulation has been developed. Algorithm enables simulation of the propagation of the sampled, coherent light field in off-axis case. Method is based on the convolution approach with off-axis kernel. Method provides exact results for distances z >> λ (wavelength) for light field intensity distribution. From the numerical point of view convolution operation is realized by twice utilization of the efficient Fast Fourier Transform (FFT) algorithm. However, it is worth to notice that off-axis kernel disables calculation of the propagation row by row and column by column. So new approach is necessary. In the proposed method of the light propagation simulation numerical effort is significantly decreased in comparison to numerical calculation of the two-dimensional integral. Numerical algorithm is included and described in this paper.

This paper presents a method of improving the Transcranial Doppler (TCD) signal by removing harmonic interferences. Such interferences, originating from medical equipment using the high power HF signals are common in a clinical environment, especially in the neighborhood of the operating theater. The Adaptive Interference Canceler based on the NLMS FIR filter has been used. The reference signal was obtained by delaying of the original TCD signal. The presented method allows significant improvement of a seriously disturbed TCD signal.

The paper presents the results of the work on high speed epiplanar photodiodes of a small active area used in laser and fiber-optic techniques and epiplanar diodes of a large active area destined for nuclear radiation detection. Also planar diodes with a large active area and thick active region assigned for detection of optical, nuclear and X radiation are discussed.

Silicon avalanche photodiodes (APDs) -- due to the effect of avalanche multiplication of carriers in their structure -- are most sensitive and fastest detectors of visible and near infrared radiation. Also the value of noise equivalent power NEP of these detectors is the smallest. In the paper, the design, technology and properties of the silicon avalanche photodiodes with a n⁺ - p - π - p⁺ epiplanar structure developed at the Institute of Electron Technology (ITE) are presented. The diameters of photosensitive area range from 0.3 mm to 5 mm. The ITE photodiodes are optimized for the detection of the 800 nm ÷ 850 nm radiation, but the detailed research on spectral dependencies of the gain and noise parameters has revealed that the spectral operating range of the ITE photodiodes is considerable wider and achieves 550 ÷ 1000 nm. These photodiodes can be used in detection of very weak and very fast optical signals. Presently in the world, the studies are carried out on applying the avalanche photodiodes in detection of X radiation and in the scintillation detection of nuclear radiation.

The method of calculating the multimode step-index fiber's luminous intensity spatial distribution was proposed. It was found that it depends strongly on the modal power distribution inside the fiber. Calculations were made for four different approximations of modal power distribution. It was concluded that measurement of fiber's luminous intensity spatial distribution could be uses to calculate the modal power distribution inside the core.

The analysis of dependences between parameters of core on light propagation in ring-core optical fibers is presented in this paper. Authors try to find the answer on following question: How should we establish values of gabarit parameters of optical fiber and index of refraction for core and cladding, to get desirable distribution of electric field in transverse intersecction of ring-core fiber. The answer on above mentioned important question is settled on the ground results of many computer simulations, which are implementation of two-step theoretical model for this kind of optical fibers.

This article aims at presenting the attempt of quantitative description of luminous flux distribution in the side-light optical fibers. The basic relations, regarding emission of the luminous flux are presented here. Construction of an algorithm, aiming at calculating balance of the radiation emitted from side-light optical fiber, was proposed.

In this paper, opto-technical properties of a modern material for optical energy transmission -- Optical Lightning Film -- were described. Luminous intensity index curves for the OLF film samples were presented. Various usages of the given material both in lighting and optical fiber areas were discussed.

This paper discusses reasons for changes in spectral composition of optical radiation emitted from side-surfaces of side-light optical fibers. Results of measurements of radiation spectrum against distance from the front-surface of the side-light, solid-core optical fiber were presented.

Side coupling between both cores takes place in a double-core otpical fiber. This means that power transformation takes place due to interaction between modes, which radiate in coupled optical fibers. In order to realize such a side coupling, it is necessary to introduce a core of the coupled optical fiber into the area of influence of radiant modes or evanescent field of the second optical fiber. The paper presents an influence of the mode number on coupling coefficient.

This paper presents the analysis of phenomenon multimode fiber in side coupling. It presents the dependence of coupling efficiency on the angle between the fiber.

the distribution of the luminous flux density in the focus of a discharge a lamp depends solely on its working position. The main goal of this work was to perform measurements of the distribution of the luminous flux density in the focus of the HQI-R 150W lamp, in various working positions. With all possible working positions for this lamp, the measured illuminance distributions are very uneven.

During the designing process for a luminaire with the light guiding plate, first it is necessary to analyze the issue of coupling light source with the light guiding plate, since only the luminous flux which is introduced into the light guiding plate might be utilized further on and become the useful flux. Theoretical calculations of the coupling index between the fluorescent lamp and the light guiding plate were made. The measurement's results confirmed the conclusions from theoretical calculations, namely that the best possible solution is placing the fluorescent lamp directly at the surface of the light guiding plate. Placing the lamp 2 millimeters from the plate's front surface causes the decrease by 20%, and further increase in the distance to 5 millimeters -- decrease by 50%.

We present development results of the web-oriented environment for distance education in the field of the semiconductor laser physics. The paper includes description of the Interactive Environment for Distance Education (IEDE) focused on connection of lecture courses and the laser simulation package LaserCAD III, which allows considering lasers directly during reading of lectures via Internet. Some examples of the package using are presented.

In Article, description of Virtual Laboratory of Power Electronics, which is placed at this address: www.isep.pw.edu.pl/ICG/vlab/, was included. The Virtual Laboratory contains multimedial presentation of Pulse Width Modulation methods, which are used in three-phase voltage inverters. Article contains short description of selected modulationn methods and description of selected applets, which are used in Virtual Laboratory of Power Electronics.

Web-based learning applications open new horizons for educators. In this work we present the computer encyclopedia designed to overcome drawbacks of traditional paper information sources such as awkward search, low update rate, limited copies count and high cost. Moreover, we intended to improve access and search functions in comparison with some Internet sources in order to make it more convenient. The system is developed using modern Java technologies (Jave Servlets, Java Server Pages) and contains systemized information about most important and explored physical effects. It also may be used in other fields of science. The system is accessible via Intranet/Internet networks by means of any up-to-date Internet browser. It may be used for general learning purposes and as a study guide or tutorial for performing laboratory works.

This paper refers issues connected with webometrics -- science, which allow conducting various researches over model and content of the Internet, especially WWW sites. Webometrics methodology connections with other disciplines and numerous examples of various, sometimes completely different Internet measures were shown. This paper presents the state of the art in webometrics.

The work describes, standardized, modular and interactive, (optical) broadband Internet based, information system for a research and didactic unit active in the university environment. The logical structure of the system was designed and realized. The structure of logical interconnections between the scientific and didactic information was embedded in the database. New solutions for the broadband processing and presentations layers were proposed. The theoretical and design considerations were implemented practically for one of the research departments at the Warsaw University of Technology. Chosen examples of the system in action were quoted.

Sometimes, during a data acquisition, we meet problems connected with random disturbances. If we know a nature of these disturbances, it is possible to remove them and prepare the collected data for a further analysis. In this article, several applications of tools to analyze a few sets acquired data will be presented. MATLAB environment was used for building these procedures.

The paper presents accuracy analyses of digital compression line which consists of digital quadrature detector, simple decimator and matched filter. Up to now analogue quadrature detectors are commonly used for many applications. These detectors suffer from bias and channel balance problems. However, the problem disappears while using digital solution. The main goal was to decrease the computation complexity needed for the processing without loosing the detection accuracy. It was achieved by using the class of digital quadrature detector with sampling frequency four times of IF frequency and simple phase correction filters.

In this paper, two linear adaptive multiuser detection schemes are presented. An adaptive MMSE detector and a blind adaptive multiuser detector belong to a class of suboptimal linear detection schemes. The strength of these adaptive solutions consists in very attractive trade-off between peformance of the detectors and their requirements regarding knowledge of parameters of the desired user as well as other users. Relatively low computational complexity of such detection algorithms is also the benefit. In order to show a performance advantage of the adaptive detectors over a classical matched filter solution (commonly applying in exiting CDMA systems), a computer simulations are carried out. They demonstrate that the adaptive linear detectors can be recognized as powerful multiuser detection tools.

The paper presents background theory and simulation results of an amplitude and quadrature component distributions of terrain backscattering for frequency band 10 - 140 GHz.

The present paper deals with simulation of tracking algorithms. Two target models are considered. All models are based on state equations using Newton matrices in the presence of Gaussian white noise. Simulated algorithm is compared with the Kalman filter. Better accuracy of simulated estimation filter is shown.

The paper presents a new maneuver detection algorithm used in variable state dimension estimator. The proposed method is based on statistical test of two hypothesis which checks probability density function of innovation process of a tracking filter. The neural networks with radial and hyperradial basis functions are applied as probability density function and distribution function estimators. The results of numerical simulations are presented. The presented approach is also suitable for fault detection and diagnosis in dynamical systems.

Peripherial Connect Interface (PCI) is a well established industry standard bus used for connecting CPU to peripherial devices. PCI gives access to many good quality and inexpensive peripherials. There are plenty of PCI host bridge chips for commonly used CPUs like x86 compatible or PowerPC. It is sometimes necessary to interface PCI device with an older or specific computer systems based on other processors, to expand their capabilities. If dedicated bridge chip is not available (or even do not exists) the bus can be interfaced via PLD integrated circuits. The paper describes ad-on PCI bridgeboard for Amiga 4000 computer (based on Motorola MC68060 CPU), designed with Altera MAX7000 PLD chips.

The paper presents the state-of-art of real time digital signal processing in aspects of DSP algorithms computational complexity and in aspect of modern DSP architecture capability.

The objective of this paper is to introduce an idea of multifunction radars' resources management. Many still existing problems connected with this topic have forced the designers, researchers and engineers to use atypical methods in order to find optimal solutions. One group of these methods focuses on applications, that base on fuzzy logic and neural networks theories. The creating fuzzy-neural controller, that supports multifunction radars' resources management is considered in this paper.

We consider the problem of estimating the direction of arrival (DOA) of multiple sources in the presence of noise. First, we introduce a narrowband signal model disturbed by white, Gaussian noise. This signal is detected by Uniform Linear Antenna Array -- ULA. Next, we discuss some properties of this signal model and its cross correlation matrix. Using this properties we introduce SINGLE SHIFT INVARIANCE algorithm for DOA estimation: ESPRIT. Next, we describe an idea of MULTIPLE INVARIANCE algorithm based on MULTIPLE INVARIANCE ESPRIT. In the last section we examine some statistical properties of both algorithms: ESPRIT and MULTIPLE INVARIANCE ESPRIT.

Differential modulations such as Delta Modulation (DM) are used for representing digital signals in small word length codes. They allow high fast acting and simplicity of specialized processors. The use of DM for the economical representation and efficient processing of the signals needs the development of the existing methods and the working out of simple and fast processing methods in real time. Therefore Discrete Cosine Transform (DCT) methods were proposed in mixed formats which have the advantages both DCT with PCM and DCT with DM. In this work there have been studied the ways of choosing DM parameters in order to use them in these methods. On the basis of the worked out computer simulation program, the accuracy of DCT with DM algorithms has been examined by means of processing signals like noise and voice. The use of DCT algorithms in DM formats is expedient to realization of neural systems.

Synthetic Aperture Radar (SAR) is a technique used to obtain high-resolution radar images. It can be carried out in two ways: Focused SAR or Unfocused SAR. Although the first method gives better resolution, it requires more computational power. The second method bases on less complicated computations and can also ensure satisfactory results. Since the aircraft's path is not ideal in real situations these two techniques require motion compensation. A simple motion compensation algorithm for Unfocused SAR presented in this paper is computationally effective and gives good results.

Radar networks for automtovie short-range applications (up to 30m) based on powerful but inexpensive 24GHz high range resolution pulse or FMCW radar systems have been developed at the Technical University of Hamburg-Harburg. The described system has been integrated in to an experimental vehicle and tested in real street environment. This paper considers the general network design, the individual pulse or FMCW radar sensors, the network signal processing scheme, the tracking procedure and possible automotive applications, respectively. Object position estimation is accomplished by the very precise range measurement of each individual sensor and additional trilateration procedures. The paper concludes with some results obtained in realistic traffic conditions with multiple target situations using 24 GHz radar network.

The paper presents an opto-electronic system for antenna beam propagation direction control, and the results of the model system measurements.

The paper presents the continuous monitoring system concept of fiber optic transmission lines. It describes the refectometric method for testing optical links and apply of WDM multiplexers providing remote attenuation measurements of the tested fibers during link operation, without the transmission interruption.

Kray is an application for creating realistic images. It is written in C++ programming language, has a text-based interface, solves global illumination problem using techniques such as radiosity, path tracing and photon mapping.

This paper introduces a software tool able to synthesize raw radar echo signals. Application was created to support radar signal processing block designers. For given set of objects, radar location and probing parameters it produces signal received by radar antenna for each probing. Signal is stored in a file for future usage. Signal synthesizer works in MATLAB environment, but to improve efficiency most time consuming parts are written in C++ programming language.

The technique of radar clutter map elaboration for land backscattering at the frequency band of 3 - 100 GHz for small grazing angles is proposed taken into consideration the terrain relief and vegetation. The sources and methods for receiving of the initial data for modeling are analyzed and described. A brief description of operation principle and area of application of specially designed neural structure (consolidation tree) in the model is presented.