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June 2007, Volume 16, Number 2

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N. Yannopoulou, P. Zimourtopoulos [references] [full-text] [Download Citations]
Total Differential Errors in One-Port Network Analyzer Measurements with Application to Antenna Impedance

The objective was to study uncertainty in antenna input impedance resulting from full one-port Vector Network Analyzer (VNA) measurements. The VNA process equation in the reflection coefficient ρ of a load, its measurement m and three errors Es, determinable from three standard loads and their measurements, was considered. Differentials were selected to represent measurement inaccuracies and load uncertainties (Differential Errors). The differential operator was applied on the process equation and the total differential error for any unknown load (Device Under Test DUT) was expressed in terms of dEs and dm, without any simplification. Consequently, the differential error of input impedance Z -or any other physical quantity differentiably dependent on ρ- is expressible. Furthermore, to express precisely a comparison relation between complex differential errors, the geometric Differential Error Region and its Differential Error Intervals were defined. Practical results are presented for an indoor UHF ground-plane antenna in contrast with a common 50 Ω DC resistor inside an aluminum box. These two built, unshielded and shielded, DUTs were tested against frequency under different system configurations and measurement considerations. Intermediate results for Es and dEs characterize the measurement system itself. A number of calculations and illustrations demonstrate the application of the method.

  1. FITZPATRICK, J. Error models for systems measurement. Microwave Journal, May 1978, vol. 21, p. 63-66.
  2. SPIEGEL, M. R. Complex Variables with an Introduction to Conformal Mapping and its Applications. McGraw-Hill, 1974, p.203.
  3. Vector Measurements of High Frequency Networks. Hewlett - Packard, 1989, p.3-6.
  4. BALLO, D. Network Analyzer Basics. Hewlett-Packard, 1998, p.1-61, 1-68.
  5. STUMPER, U. Influence of TMSO calibration standards uncertainties on VNA S-parameters measurements. IEEE Transactions on Instrumentation and Measurements, April 2003, vol. 52, no. 2, p. 311 - 315.
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  7. Precision Microwave Instruments and Components. Maury Microwave Corporation, 1996, p.132.
  8. RICHMOND, J. H. Radiation and scattering by thin-wire structures in a homogeneous conducting medium. IEEE Transactions on Antennas and Propagation, March 1974, vol. 22, issue 2, p. 365

Keywords: Microwave measurements, network analyzer, meas-urement errors, reflection coefficient, antenna input impedance

P. Cerny, M. Mazanek [references] [full-text] [Download Citations]
Optimization of Transient Response Radiation of Printed Ultra Wideband Dipole Antennas (Using Particle Swarm Optimization Method)

In case of particular ultra wideband applications (i.e. radar, positioning, etc.), it is crucial to know the transient responses of antennas. In the first part of the paper, the optimization process searches for the dipole shape that accomplishes two required parameters i.e. a good matching and a minimal distortion. The particle swarm optimization method was used in the process of the dipole shape optimization. As a result, the optimized ultra wideband dipole is perfectly matched. Moreover, it minimally distorts the applied signal. The second part of the paper discusses the influence of the feeding circuit on radiating parameters and on the dipole antenna matching.

  1. Federal Communications Commission, First Order and Report, Revision of Part 15 of the Commission's Rules Regarding UWB Transmission Systems, FCC 02-48, April 22, 2002.
  2. PIKSA, P., SOKOL, V. Small Vivaldi antenna for UWB. In Proceedings of the Conference RADIOELEKTRONIKA 2005. Brno (Czech Republic), 2005, p. 490-493.
  3. CERNY, P., MAZANEK, M. Optimized ultra wideband dipole antenna. In Proceedings of the 18th International Conference of Applied Electromagnetics and Communications. Dubrovnik (Croatia), 2005.
  4. CERNY, P., MAZANEK, M., PIKSA, P., SOKOL, V., KORINEK, T. Transient response optimization of ultra wideband antennas (using particle swarm optimization). In Proceedings of the European Conference on Antennas and Propagation. Nice (France), 2006, p. 168.
  5. SCHANTZ, H. G. Bottom fed planar elliptical UWB antennas. In Proceedings of the Ultra Wideband Systems and Technologies. Reston (USA), 2003, p. 219-223.
  6. ROBINSON, J., RAHMAT-SAMII, Y. Particle swarm optimization in electromagnetics. IEEE Transactions on Antennas and Propagation, 2004, vol. 52, no. 2, p. 397-407.
  7. KI-HAK KIM, YOUNG-JUN CHO, SOON-HO HWANG. Design of a Band-rejected UWB planar monopole antenna with two parasitic patches. In Proceedings of the Conference ISAP2005. Seoul (Korea), 2005, p. 957-960.

Keywords: Ultra wideband antennas, UWB, particle swarm optimization, PSO, transient response radiation, dipole feeding

M. Cifra, E. V. Wijk, H. Koch, S. Bosman, R. V. Wijk [references] [full-text] [Download Citations]
Spontaneous Ultra-Weak Photon Emission from Human Hands Is Time Dependent

Ultra-weak photon emission in the visible range was measured on palm and dorsal side of left and right hand by means of a low noise photomultiplier system. To study the dynamics of this photon emission in a 24 h period photon emission was recorded in 2 h intervals in 5 experiments, utilizing strict protocols for dark adaptation and recording of subjects.
Fluctuations in photon emission in the course of 24 h period were demonstrated for each anatomic location. Mean photon emission over the 24 h period differed both between subjects and hand locations. To detect a pattern in the fluctuations the mean value for each location of each subject in each experiment was utilized to calculate fluctuations during the course of 24 h for each anatomical location.
The fluctuations in photon emission in the course of 24 h were more at dorsal sides than palm sides. The correlation between fluctuations in palm and dorsal side was not apparent. During the 24 h period a change in left-right symmetry occurred for the dorsal side but not for the palm of the hands. Photon emission at the left dorsal location was high at night, while the right dorsal side emitted most during the day.
It is concluded that a daily rhythm in photon emission can be recorded from both the dorsal and palm sides of the hands.

  1. FROHLICH, H. Bose condensation of strongly excited longitudinal electric modes. Phys. Letters Ser. A, 1968, vol. 26, p. 402-403.
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  10. JELINEK, F., POKORNY J., SAROCH, J., HASEK, J. Experimental investigation of electromagnetic activity of yeast cells at milimeter waves. Electromagnetic Biology and Medicine, 2005, vol. 24, no. 3, p. 301-307.
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  15. POPP, F. A., BELOUSSOV, L. Integrative Biophysics - Biophotonics. Kluwer Academic Publishers, 2003.
  16. SHEN, X., VAN WIJK, R. Biophotonics - Optical Science and Engineering of the 21st century. Springer, 2005.
  17. BELOUSSOV, L. V., VOEIKOV, V. L., MARTYNYUK, V. S. Biophotonics and Coherent Systems in Biology. Springer, 2006.
  18. VAN WIJK, R., KOBAYASHI, M., VAN WIJK, E. P. Anatomic characterization of human ultra-weak photon emission with a moveable photomultiplier and CCD imaging. Journal of Photochemistry and Photobiology B., 2006, Apr 3, vol. 83(1), p. 69-76.
  19. VAN WIJK, R., VAN WIJK, E. P. Multi-site recording and spectral analysis of spontaneous photon emission from human body. Forschende Komplementarmedizin und Klassische Naturheilkunde, 2005, 12, p. 96-106.
  20. KOBAYASHI, M. Two-dimensional imaging and spatiotemporal analysis of biophoton imaging technique and applications for biomedical imaging. Biophotonics - Optical Science and Engineering of the 21st century. Eds. Xu Shen, Roeland Van Wijk. Springer, 2005, p. 155.
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  25. BAYDAS, G., GURSU, M. F., YILMAZ, S., CANPOLAT, S., YASAR, A., CIKIM, G., CANATAN, H. Daily rhythm of glutathione peroxidase activity, lipid peroxidation and glutathione levels in tissues of pinealectomized rats. Neuroscience Letters, 2002, 323, p.195-198.

Keywords: Biophoton, ultra-weak photon emission, bio-photonics, hand dorsum, palm, left-right symmetry, hand

F. Sagnard [references] [full-text] [Download Citations]
Analytical Modeling of Insulated Dipole Applicators for Interstitial Hyperthermia: a Review

Microwave hyperthermia appears as an adjuvant technique to heat relatively small tumors in a minimally invasive way. As this technique is based on interstitial antennas, we propose a review of the physical phenomena involved in the radiation of such antennas in a dispersive medium, using the different analytical modeling developed since the 1970\'s. These modeling have been implemented in a freely available software tool, that will allow antenna designers and medical researchers to perform rapid parameter studies to further understand the role of the several parameters involved; this tool will also help the interpretation of results issued from numerical simulations. Simulation results associated with different antenna geometries are presented and compared to results obtained by several authors.

  1. CONWAY, J., ANDERSON, A. P. Electromagnetic techniques in hyperthermia. Clin. Phys. Physiolog. Meas., 1986, vol. 7, no. 4, p. 287 - 318.
  2. CHOU, C. K. Application of electromagnetic energy in cancer treatment. IEEE Trans. Instrum. Meas., 1988, vol. 37, no. 4, p. 547 - 551.
  3. SIMON, C. J., DUPUY, D. E., MAYO-SMITH, W. W. Microwave ablation: Principles and applications. Radiographics, vol. 25, 2005, p. 69-83.
  4. Mini-Special Issue on RF/Microwave Applications in Medicine, Part 1, 2. IEEE Trans. Microw. Theory Tech., 2000, vol. 48, no. 11, p. 1783 - 2198.
  5. STAUFFER, P. R. Evolving technology for thermal therapy of cancer. Int. J. Hyperthermia, vol. 21, no. 8, 2005, p. 731 - 744.
  6. HAEMMERICH, D., LASEKE, P. F. Thermal tumour ablation: Devices, clinical applications and future directions. Int. J. Hyperthermia, vol. 21, no. 8, 2005, p. 755 - 760.
  7. JOINES, W. T., ZHANG, Y., LI, C., JIRTLE, R. L. The measured electrical properties of normal and malignant human tissues from 50 to 900 MHz. Medical Physics, vol. 21, no. 4, 1994, p. 547 - 550.
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  9. KING, R. W. P., SHEN, L. C., WU, T. T. Embedded insulated antennas for communication and heating. Electromagnetics, 1981, vol. 1, p. 51 - 72.
  10. KING, R. W. P., TREMBLY, B. S., STROHBEHN, J. W. The electromagnetic field of an insulated antenna in a conductive or dielectric medium. IEEE Trans. Microw. Theory Tech., vol. 31, no. 7, 1983, p. 574 - 583.
  11. CASEY, J. P., BANSAL, R. The near field of an insulated dipole in a dissipative dielectric medium. IEEE Trans. Microw. Theory Tech., 1986, vol. 34, no. 4, p. 459 - 463.
  12. ISKANDER, M. F., TUMEH, A. M. Design optimization of interstitial antennas. IEEE Trans. Biomed. Eng., vol. 36, no. 2, 1989, p. 238.
  13. CLIBBON, K. L., McCOWEN, A. Efficient computation of SAR distributions from interstitial microwave antenna arrays. IEEE Trans. Microw. Theory Tech., 1994, vol. 42, no. 4, p. 595 - 601.
  14. WU, L. K., SU, D. W. F., TSENG, B. C. A fast algorithm for computing field radiated by an insulated dipole antenna in dissipative medium. IEEE Trans. Microw. Theory Tech., vol. 44, no. 12, 1996, p. 2290 - 2293.
  15. STUART TREMBLY, B., WILSON, A. H., SULLIVAN, M. J., STEIN, A. D., WONG, T. Z., STROHBEHN, J. W. Control of the SAR pattern within an interstitial microwave array through variation of antenna driving phase. IEEE Trans. Microw. Theory Tech., vol. 34, no. 5, 1986, p. 568 - 571.
  16. ZHANG, Y., JOINES, W. T., OLESON, J. R. Microwave hyperthermia induced by a phased interstitial antenna array. IEEE Trans. Microw. Theory Tech., vol. 38, no. 2, 1990, p. 217 - 221.
  17. CHERRY, P. C., ISKANDER, M. F. FDTD analysis of power deposition patterns of an array of interstitial antennas for use in microwave hyperthermia. IEEE Trans. Microw. Theory Tech., vol. 40, no. 8, 1992, p. 1692 - 1700.
  18. CHERRY, P. C., ISKANDER, M. F. Calculations of heating patterns of an array of microwave interstitial antennas. IEEE Trans. Biomed. Eng., vol. 40, no. 8, 1993, p. 771 - 778.
  19. EPPERT, V., TREMBLY, B. S., RICHTER, H. J. Air cooling for an interstitial microwave hyperthermia antenna: Theory and experiment. IEEE Trans. Biomed. Eng., vol. 38, no. 5, 1991, p. 450 - 460.

Keywords: Insulated antenna, dipole antennas, radiation, hyper-thermia, dissipative media, microwave antenna arrays

B. Guenad, S. M. Meriah, F. T. Bendimerad [references] [full-text] [Download Citations]
Multibeam Antennas Array Pattern Synthesis Using a Variational Method

In this paper a new method is described for multibeam antennas synthesis where both the amplitude and phase of each radiating element is a design variable. The developed optimization method made possible to solve the synthesis problem and to answer all the constraints imposed by the radiation pattern. Two approaches for visualizing satellite antenna radiation patterns are presented. Gain-level contours drawn over a geographical map gives clearest qualitative information. A three-dimensional (3D) surface plot displays the qualitative shape of the radiation pattern more naturally. The simulations results have shown power, precision and speed of the variational method with respect to the constraints imposed on radiation pattern of the of multibeam antennas network.

  1. SUDHAKAR, K. R., MORIN, G. A., TANG, M. Q, RICHARD, S. Development of a 45 GHz multiple-beam antenna for military satellite communications. IEEE Transaction on Antennas and Propagation, 1995, vol. 45, no. 10, p. 1036-1047.
  2. CAILLOCE, Y., CAILLE, G., ALBERT, I., LOPEZ, J. M. A Ka-band direct radiating array providing multiple beams for a satellite multimedia mission. In Phased Array Systems and Technology, IEEE International Conference. 2000, p.403-406.
  3. PINSARD, B., RENAUD, D. Synthesis method for triangular lattice planar arrays using FFT algorithm. In Proceeding of the Int. Symposium on Antennas JINA 1992. Nice (France), 1992, p. 51-54.
  4. KLEIN, C. Design of shaped-beam antennas through minimax gain optimization. IEEE Transaction on Antenna and Propagation, 1984, vol. 32, no. 9, p. 963 - 968.
  5. LUH, H. On the radiation pattern of a multibeam antenna. IEEE Transact. on Antenna and Propag., 1976, vol. 24, no. 1, p. 101-102.
  6. RAO, S. Parametric design of multiple beam reflector antennas. IEEE Transactions on Antennas and Propagation, 2002, vol. 1, p. 650 - 653.
  7. COMBES, P. Microwaves Passive Circuit, Propagation, Antennas. 2nd ed. Dunod, 1997.
  8. MAILOUX, R. J. Phased Array Antenna Handbook. 2nd ed. Artech House, 2005.
  9. DION, A.R., RICARDI, L.J. Physical limitations on interference reduction by antenna pattern shaping. IEEE Transactions on Antennas and Propagation, 1975, vol. 23, no. 5, p. 639-646.
  10. MAYHAN, J. Nulling limitation for a multiple beam antenna. IEEE Transaction on Antenna and Propag., 1976, vol. 24, p. 769 to 779.
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  12. RAO, S. K. Parametric design and analysis of multiple beam reflector antennas for satellite communication. IEEE Transaction on Antennas and Propagation, 2003, vol.45, p. 26 - 34.
  13. GUENAD, B. Synthesis of Multifeed Reflectors Antennas for Communication Satellite. Thesis, Univ. of Tlemcen. Algeria, 2005.

Keywords: Multibeam antennas, optimization, radiation pattern synthesis, variational method

L. Dolivka, J. Hospodka [references] [full-text] [Download Citations]
Switched-Capacitor Filter Optimization with Respect to Switch On-State Resistance and Features of Real Operational Amplifiers

The optimization of a switched-capacitor filter, which implements a biquadratic section, is described in this paper. The aim of the optimization is to obtain a required magnitude frequency response of the filter. The optimization takes into account both one of the features of real switches - their on-state resistance, and the features of real operational amplifiers - finite voltage gain and finite unity-gain bandwidth. An optimal dynamic range is to be achieved as well. The differential evolution - a kind of evolutionary algorithms - is employed for the optimization. The filter is designed by the usual way with ideal switches and ideal operational amplifiers at first. The analysis of this filter with real switches and real operational amplifiers proves that there is a significant difference between its magnitude frequency response and the one with ideal components. Hence, the optimization is applied for finding component values so that the magnitude frequency response is as similar to the one with ideal components as possible. As for other main real features of operational amplifiers - input and output resistance - it is shown that their effect is small.

  1. ANANDA MOHAN, P. V., RAMACHANDRAN, V., SWAMY, M. N. S. Switched Capacitor Filters - Theory, Analysis and Design. Prentice Hall International, 1995, ISBN 0-13-879818-4.
  2. CORNE, D., DORIGO, M., GLOVER, F. New Ideas in Optimization. London: McGraw-Hill, 1999, ISBN 0-07-709506-5.
  3. MARIK, V., STEPANKOVA, O., LAZANSKY, J. et al. Artificial Intelligence (in Czech), vol. 1, 2, 3, and 4. Prague: Academia, 1993, 1997, 2001, and 2003, ISBN 80-200-0496-3, 80-200-0504-8, 80-200-0472-6, and 80-200-1044-0.
  4. ZELINKA, I. Artificial Intelligence in Global Optimization Problems (in Czech). Prague: BEN, 2002, ISBN 80-7300-069-5.
  5. GOLDBERG, D. E. Genetic Algorithms in Search, Optimization, and Machine Learning. Reading, Massachusetts: Addison-Wesley Publishing Co., 1989, ISBN 0-201-15767-5.
  6. STORN, R., PRICE, K. Differential evolution - a simple and efficient heuristic for global optimization over continuous spaces. Journal of Global Optimization, 1997, vol. 11, no. 4, pp. 341-359. Kluwer Academic Publishers, ISSN 0925-5001.
  7. STORN, R. Differential Evolution Design of an IIR-filter with Requirements for Magnitude and Group Delay. Technical report TR-95-026. ICSI, 1995.
  8. DOLIVKA, L., HOSPODKA, J. Elimination of switch on-state resistance effect on a switched-capacitor filter characteristic. In Proceedings of Conference PRIME 2006, pp. 177-180. IEEE, 2006, ISBN 1-4244-0156-9.
  9. TICHA, D., MARTINEK, P. OTA-C lowpass design using evolutionary algorithms. In Proceedings of ECCTD'05, vol. 2, pp. 197-200. Cork: University College Cork, 2005, ISBN 0-7803-9066-0.
  10. BICAK, J., HOSPODKA, J. PraSCAn - Maple package for analysis of real periodically switched circuits. In Proceedings of Maple Conference 2005, pp. 8-18. Waterloo Ontario: Maplesoft, a division of Waterloo Maple Inc., ISBN 1-894511-85-9.
  11. SMITH, M. WinSpice User's Manual.
  12. BICAK, J., HOSPODKA, J. Frequency response of switched circuits in SPICE. In Proceedings of ECCTD'03, pp. I-333-I-336. Krakow (Poland): IEEE, 2003, ISBN 83-88309-95-1.
  13. STORN, R. System Design by Constraint Adaptation and Differential Evolution. Technical report TR-96-039. ICSI, 1996.
  14. VESTENICKY, M., VESTENICKY, P. Evolutionary algorithms in design of switched capacitors circuits. In Proceedings of Digital Technologies 2004, pp. 34-37. Zilina (Slovakia): EDIS - Zilina University publisher, 2004, ISBN 80-8070-334-5.

Keywords: Switched-capacitor circuit, band-pass filter, optimiza-tion, evolutionary algorithm, differential evolution

Z. Elhadj [references] [full-text] [Download Citations]
A New 3-D Piecewise-Linear System for Chaos Generation

We propose in this paper a new simple continuous-time piecewise-linear three dimensional system for chaos generation. Nonlinearity in this model is introduced by the characteristic function of the Chua\'s circuit given in [1]. Simulated results of some chaotic attractors are shown and justified numerically via computing the largest Lyapunov exponent. The possibility and the robustness of the circuitry realization is also given and discussed.

  1. CHUA, L. O., KOMURO, M., MATSUMOTO, T. The double scroll family. Parts I and II, IEEE Trans. Circuits. Syst., 1986, 33, p. 1073-1118.
  2. SPROTT, J. C. Some simple chaotic flows. Phys. Rev. E50, R647650, 1994.
  3. CHUA, L. C., LIN, G. N. Canonical realization of Chua's circuit family. IEEE Transactions in Circuit and Systems, 1990, vol. 37, no. 7, p. 885-902.
  4. KARADZINOV, L. V., JEFFERIES, D. J., ARSOV, G. L., DEANE, J. H. B. Simple piecewise-linear diode model for transient behaviour. International Journal of Electronics, 1996, vol.78, no. 1, pp. 143 to 160.
  5. KOMURO, M., TOKUNAGA, R., MATSUMOTO, T., HOTTA, A. Global bifurcation analysis of the double scroll circuit. Int. J. Bifurcation and Chaos, 1991, vol. 1, no. 1, p. 139-182.
  6. BAHIOUS, E. H., JARRAY, P. Lorenz attractor from differential equation with piecewise linear terms. Int.J. Bifurcation and Chaos, 1993, vol. 3, no. 1, p. 201-210.
  7. KENNEDY, M. P. Robust OP Amp realization of Chua's circuit. Frequenz, 1992, vol. 46, no. 3-4, p. 66-80.
  8. CRUZ, J. M., CHUA, L. O. An IC chip of Chua's circuit. IEEE Trans. Circuits Syst.-II: Analog and Digital Signal Processing, 1993, 40(10), p. 614-625.
  9. SPROTT, J. C. A new class of chaotic circuit. Physics Letters A, 2000, 266, p. 19-23.
  10. SPROTT, J. C. Simple chaotic systems and circuits. Am. J. Phys., 2000, vol. 68, no. 8, p. 758-763.

Keywords: Piecewise-linear system, new chaotic attractor, circuitry realization, Chua’s diode

P. Dobias [references] [full-text] [Download Citations]
DRM Transmitter with FPGA Device

This paper presents the design and analysis of the OFDM modulator for Digital Radio Mondiale (DRM) standard. Attention is paid to the digital signal processing in FPGA devices. The system performs carrier modulation of the complex envelope of the DRM signal. It generates a phase modulated carrier and a magnitude signal that are used with a Pulse Step Modulation (PSM) transmitter. The system has been implemented by using VHDL language. Altera FPGA development kit with an additional board is used and functional tests and measurements are presented. Simulations evaluating the quality of the output signal were done.

  1. Digital Radio Mondiale (DRM); System Specification (ETSI ES 201 980 V2.1.1 2004-06), ETSI Standard, 2004.
  2. ETSI EN 302 245-2 V1.1.1 (2004-11): Electromagnetic compatibility and Radio spectrum Matters (ERM); Transmitting equipment for the Digital Radio Mondiale (DRM) broadcasting service; Part 2: Harmonized EN under article 3.2 of the R&TTE Directive.
  3. FFTW, [online],
  4. Open-Source Software Implementation of a DRM-Receiver, [online],
  5. DONADIO, M. CIC Filter Introduction. [online], 18 July 2000.
  6. ANDRAKA, R. A Survey of CORDIC algorithms for FPGA based computers. In Proceedings of FPGA 98.1998 International Symposium on Field Programmable Gate Arrays. ACM, New York (NY, USA), 1998, pp. 191-200.
  7. PAJSKR, K. Vykonovy zesilovac ve tride D. M.S. thesis, CTU in Prague, FEE, 2004 (in Czech).
  8. HUJER, M., DOBIAS, P. Analysis of OFDM transmitter based on digital amplitude modulator. Radio-Electronics, Electrical and Power Engineering. 2005, pp.47-49, Moskovskij energeticeskij institut, Moscow.
  9. DOBIAS, P., HUJER, M. Analysis of OFDM modulator considering hardware implementation. Radio-Electronics, Electrical and Power Engineering. 2005, pp.45-47, Moskovskij energeticeskij institut, Moscow.
  10. DOBIAS, P. Influence of phase signal discontinuities on MER in OFDM modulator hardware realization. In 9th International Student Conference on Electrical Engineering, POSTER 2005. Prague (Czech Republic), 2005, p. C36.
  11. ULOVEC, K. Measurement on DRM Transmitter. In Radioelektronika 2006 - Conference Proceedings. Bratislava (Slovak Republic), Slovak University of Technology, 2006, pp. 129-132. ISBN 80-227-2388-6.

Keywords: OFDM, FPGA, modulator, DRM, digital signal processing

I. Behunek, P. Fiala [references] [full-text] [Download Citations]
Phase Change Materials for Thermal Management of IC Packages

This paper deals with the application of phase change materials (PCM) for thermal management of integrated circuits as a viable alternative to active forced convection cooling systems.
The paper presents an analytical description and solution of heat transfer, melting and freezing process in 1D which is applied to inorganic crystalline salts. There are also results of numerical simulation of a real 3D model. These results were obtained by means of the finite element method (FEM). Results of 3D numerical solutions were verified experimentally.

  1. ADAM, J. Warme- und Kuhlmanagement in elektronischen Geraten. Elektronik Praxis, 2007, vol. 3, p. 74-76.
  2. Ansys User's Manual. Huston (USA): SVANSON ANALYSYS SYSTEM, Inc., 1994-2006.
  3. ARSLANTURK, C. Small-time analytical solution of phase change problems in cylindrical and spherical domains. Journal of Thermal Sciences and Technology, 2004.
  4. BEHUNEK, I. Properties of inorganic PCM. In Honeywell EMI conference and competition 2005. Brno (Czech Republic), 2005. ISBN 80-214-2942-9.
  5. FIALA, P. Induction Flowmeter Model DN-100 (research report). UTEE FEKT VUT, Brno, 2001 (in Czech).
  6. FIALA, P. Transformer Short Test Modeling. PhD thesis. UTEE FEKT VUT, Brno, 1998 (in Czech).
  7. KOZEL, K. Numerical Solution Methods of Flow Problems I. Prague: CVUT Publishing (in Czech).
  8. LAMBERG, P., LEHTINIEMI, R., HENELL, A-M. Numerical and experimental investigation of melting and freezing in phase change material storage. Applied Mathematical Modelling 32, 2004.
  9. LANE, G.A. Solar Heat Storage: Latent Heat Materials, Volume II: Technology. Boca Raton (Florida, USA): CRC Press, Inc., 1986.
  10. RIHA, J. Hydrodynamic and Dispersive Effects Mathematical Modeling. Brno: VUT Publishing, 1997 (in Czech). ISBN 80-214-0827-8.
  11. SPECHT, B. Modellierung von beheizten laminaren und turbulenten Stromungen in Kanalen beliebigen Querschnitts. Braunschweig (Germany): Technische Universitat Carolo-Wilhelmina, 2000.
  12. PISZACHICH, W. S. Nonlinear Models of Flow, Diffusion and Turbulence. Leipzig (Germany): Teubner Verlagsgessellschaft, 1985.
  13. WILCOX, D.C. Turbulence Modeling for CFD. La Canada (California, USA): DCW Industries, Inc., 1994.
  14. ZHANG, Y. Finite Elemente zur Berechnung instationarer Stromungen mit bewegten Wandungen. Stuttgart (Germany): Universitat Stuttgart, 1996.

Keywords: Phase change, FEM, heat, integrated circuit

M. Kroul [references] [full-text] [Download Citations]
Automatic Speech Segmentation Based on HMM

This contribution deals with the problem of automatic phoneme segmentation using HMMs. Automatization of speech segmentation task is important for applications, where large amount of data is needed to process, so manual segmentation is out of the question. In this paper we focus on automatic segmentation of recordings, which will be used for triphone synthesis unit database creation. For speech synthesis, the speech unit quality is a crucial aspect, so the maximal accuracy in segmentation is needed here. In this work, different kinds of HMMs with various parameters have been trained and their usefulness for automatic segmentation is discussed. At the end of this work, some segmentation accuracy tests of all models are presented.

  1. KROUL, M. Triphone-Based Speech Synthesis. Diploma thesis, Technical University of Liberec, 2006. (in Czech)
  2. NOUZA, J., MYSLIVEC, M. Methods and application of phonetic label alignment in speech processing tasks. Radioengineering, 2000, vol. 9, no. 4, p. 1-7.
  3. HORAK, P. Automatic speech segmentation based on alignment with a text-to-speech system. In Improvements in Speech Synthesis. Ed. Keller, E.; Bailly, G.; Monaghan, A.; Terken, J.; Huckvale, M. Chichester: J. Wiley, 2002, p. 328-338.
  4. MATOUSEK, J. Text-to-Speech Synthesis Using Statistical Approach for Automatic Unit-Database Creation. Dissertation thesis, University of West Bohemia, Pilsen, 2000. (in Czech)
  5. HUANG, X., ACERO, A., HON, H. Spoken Language Processing. Prentice Hall, 2001, ISBN 0-13-022616-5.
  6. NOUZA, J. Spectral variation functions applied to acoustic-phonetic segmentation of speech signals. In Speech Processing (Forum Phoneticum, 63), pp. 43-58, 1997.
  7. YOUNG, S., KERSHAW, D., ODELL, J., OLLASON, D., VALCHEV, V., WOODLAND, P. The HTK Book, version 2.2. Entropic Ltd., 1999.

Keywords: Speech processing, automatic segmentation, speech database, HMM, monophones, triphones, alignment

J. Malek, J. Nouza, T. Klimovic [references] [full-text] [Download Citations]
Automatic Classifiers for Medical Data from Doppler Unit

Nowadays, hand-held ultrasonic Doppler units are often used for noninvasive screening of atherosclerosis in arteries of the lower limbs. The mean velocity of blood flow in time and blood pressures are measured on several positions on each lower limb. This project presents software that is able to analyze such data and classify it in real time into selected diagnostic classes. It is also capable of giving a notice of some errors encountered during measuring. At the Department of Functional Diagnostics in the Regional Hospital of Liberec a database of several hundreds signals was collected. In cooperation with the specialist, the signals were manually classified into four classes. Consequently selected signal features were extracted and used for training a distance and a Bayesian classifier. Another set of signals was used for evaluating and optimizing the parameters of the classifiers. This paper compares the results of the software with those provided by a human expert. They agreed in 89 % cases.

  1. TRANSATLANTIC INTER-SOCIETY CONSENSUS (TASC), Management of Peripheral Arterial Disease (PAD). International Angiology Suppl. 1, 2000.
  2. ROSE, S. C. Non-invasive vascular laboratory for evaluation of peripheral arterial occlusive disease. Journal of Vascular and Interventional Radiology, 2000, p.1107-1114.
  3. ROZMAN, J. et al. Diagnostics of ischemic disease of lower limbs via Doppler measuring of blood flow velocity (in Czech). Lekar a technika, NTS CLS J.E.P, Praha, 1995, pp.76-78, 100-102, 120-123.
  4. ROZMAN, J. Comparison of results of AVG signal classification (in Czech). Lekar a technika, NTS CLS J.E.P, Praha, 1995, pp. 9-11.
  5. LEE, H. G., YUM, M. K. Fourier Transformation of arterial Doppler waveforms of the lower extremity. Journal of Clinical Ultrasound, 2004, vol. 32, no. 6, p. 277-285.
  6. MIAO, J. et al. Computer based pattern recognition on Doppler spectral waveform of intra-cranial blood flow. Comput. Biol. Med., 1995, p. 53-63.
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Keywords: Medical data recognition, hand-held ultrasonic Doppler unit, peripheral arterial disease

M. Mojzes, J. Polec [references] [full-text] [Download Citations]
A Three-Level Hierarchical Encoder Using Shape Independent Transform

In this paper a scheme for utilizing shape independent basis functions for a hierarchical multiresolution image compression is shown. First, an image is segmented and its segments\' boundaries are polygon approximated, thus achieving an image mask. Second, this image mask and the image are used as an input of a three-level hierarchical encoder. The hierarchical encoder subsamples the image and the image mask and encodes them shape independently; it produces an output bit stream on a respective level that is also used on lower level(s) for further coding. On the base level a triangulation of the image mask is performed for superior performance. Another compression mode is, hence, introduced for the shape independent transform coding.

  1. GHANBARI, M. Video Coding: An Introduction to Standard Codecs. IEE, London, 1999, p. 60-62.
  2. PAL, N. R., PAL, S. K. A review on image segmentation techniques. Pattern Recognition, 1993, vol. 26, no. 9, p. 1277 - 1294.
  3. DENG, Y., MANJUNATH, B. S. Unsupervised segmentation method for colour-texture regions in images and video. IEEE Transactions on Pattern Analysis and Machine Intelligence, August 2001,
  4. GONZALES, R. C., WINTZ, P. Digital Image Processing. 2nd ed. Reading. Addison-Wesley Publishing Company, Tokyo, 1987.
  5. KOLINGEROVA, I. On triangulations. In Computational Science and Its Applications - ICCSA 2004: International Conference, Proceedings, Part II. Assisi (Italy), May 14-17, 2004, p. 544 - 553.
  6. KAUP, A., AACH, T. Coding of segmented images using shape-independent basis functions. IEEE Transaction on Image Processing, 1998, vol.7, no.7, p. 937-947.
  7. POLEC, J., PAVLOVICOVA, J., VANYA, R., KARBULIKOVA, T., MASLIK, L., PARTYK, M. New scheme for region approximation and coding with shape independent transform. In Proceedings IAPRS, The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Graz (Austria), 2002, vol. XXXIV, part 3A/B, p. B-214-217.
  8. VARGIC, R., PROCHASKA, J. An adaptation of shape adaptive wavelet transform for image coding. In EURASIP2005. Smolenice (Slovakia), June 29 - July 2, 2005.
  9. BIEMOND, J., et al. Image and Video Compression Learning Tool VcDemo,, 2004.
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  11. POLEC, J., PAVLOVICOVA, J., KARBULIKOVA, T. Application of shape-independent orthogonal transforms for image interpolation. Radioengineering, 2002, vol. 11, no. 1, p. 27-30.
  12. PARTYK, M., POLEC, J., KOLINGEROVA, I. Hybrid scheme with triangulations for transform coding. Radioengineering, 2003, vol. 12, no. 3, p. 42-45.
  13. KARBULIKOVA, T., POLEC, J. Extrapolation of incomplete image data with Discrete Orthogonal Transforms. Radioengineering, 2004, vol. 13, no. 4, p. 35-37.
  14. WU, X., FANG, Y. Segmentation-based progressive image coding. In Data Compression Conference, 1993, p. 262-271.

Keywords: Image compression, hierarchical multiresolution encoding, shape independent transform

R. Pracko, J. Polec, K. Hasenohrlova [references] [full-text] [Download Citations]
Segmentation Based Image Scanning

The submitted paper deals with separate scanning of individual image segments. A new image processing approach based on image segmentation and segment scanning is presented. The resulting individual segments 1-dimensional representation provides higher neighbor pixel similarity than the 1-dimensional representation of the original image. This increased adjacent pixel similarity was achieved even without application of different recursive 2-dimensional scanning methods [4], such as Peano-Hilbert scanning method [1]. The resulting 1-dimensional image representation provides a good base for applying lossless compression methods, such as the entropic coding. The paper contains also results analysis of the traditional method scanned segment pixels and adjacent pixel differences from the entropy point of view. As these results indicate the lossy compression methods could be applicable using this approach as well and might improve the final results as confirmed by simple prediction algorithm results presented in this paper. More complex and sophisticated lossy compression algorithms application will be a part of the future work.

  1. ANSARI, A., FINEBERG, A. Image data compression and ordering using Peano Hilbert scan and lot. IEEE Transactions on Consumer Electronics, 1992, vol. 38, pp. 436-445.
  2. LEMPEL, A., ZIV, J. Compression of individual sequences via variable rate coding. IEEE Transactions on Information Theory, 1978, vol. 24, pp. 530-536.
  3. MANICCAM, S. S., BOURBAKIS, N. G. Lossless image compression and encryption using SCAN. Pattern Recognition, Pattern Recognition Society, 2001, vol. 34, pp. 1229 - 1245.
  4. REVITEL DAFNER, COHEN-OR, D., YOSSI, MATIAS Context-based space filling curves. In EUROGRAPHICS '2000, vol. 19, no.3.
  5. YINING, D., MANJUNATH, B. S, HYUNDOO, S. Color image segmentation. In Proc. of the Conference on Computer Vision and Pattern Recognition (CVPR '99). Ft. Collins (CO, USA), 1999. IEEE Computer Society 1999, pp. 2446-2451.
  6. PAVLOVICOVA, J., ORAVEC, M., MOKOS, M., KELESI, M., Error concealment using neural networks for block-based image coding. In Proc. of the 5th EURASIP Conference focused on Speech and Image Processing, Multimedia Communications and Services. Smolenice (Slovakia), 2005, pp. 52-57.
  7. PETRAS, M., PILKA, F., ORAVEC, M., Predicition of telecommunication data by neural networks. Journal EE - Electrotechnics and Energetics, October 2006, pp. 122-126.

Keywords: Segmentation, scanning, adjacent pixel similarity, pixel differences