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Bilski P.,Institute of Radioelectronics
Geotechnical Engineering for Infrastructure and Development - Proceedings of the XVI European Conference on Soil Mechanics and Geotechnical Engineering, ECSMGE 2015 | Year: 2015

The paper presents the application of the data clustering methods for the automated generation of the 3D soil profile. The software was created for this purpose, acquiring multiple measurement data sets from separate probing locations in the selected site and performing data analysis. The latter was conducted based on multiple in-situ tests involving CPT and DMT investigations. This way it was possible to generate profiles using only one type of the probe or to combine data from multiple probes to obtain the profile with greater accuracy. Popular unsupervised learning approaches, i.e. graph clustering and nearest neighbour were used for data analysis and their performance compared. The conducted experiments consisted in generating soil categories based on multiple sets, presenting them in the graphical, three-dimensional form. Parameters of clustering methods (such as the threshold separating different soil categories or the number of desired groups) and their impact on the obtained profiles were verified. The approach was tested in selected sites within the Warsaw University of Life Sciences campus. The obtained profiles were also compared to the ones generated based on the boreholes, which allowed for confirming their usefulness. The resolution of the approach (the number of different categories obtainable) was also tested. © The authors and ICE Publishing: All rights reserved, 2015.


Coquillat D.,CNRS Charles Coulomb Laboratory | Marczewski J.,Polish Institute of Electron Technology | Kopyt P.,Institute of Radioelectronics | Dyakonova N.,CNRS Charles Coulomb Laboratory | And 3 more authors.
Optics Express | Year: 2016

Phenomena of the radiation coupling to the field effect transistors based terahertz (THz) detectors are studied. We show that in the case of planar metal antennas a significant portion of incoming radiation, instead of being coupled to the transistors, is coupled to an antenna substrate leading to responsivity losses and/or cross-talk effects in the field effect based THz detector arrays. Experimental and theoretical investigations of the responsivity versus substrate thickness are performed. They clearly show how to minimize the losses by the detector/ array substrate thinning. In conclusion simple quantitative rules of losses minimization by choosing a proper substrate thickness of field effect transistor THz detectors are presented for common materials (Si, GaAs, InP, GaN) used in semiconductor technologies. ©2016 Optical Society of America.


Coquillat D.,CNRS Charles Coulomb Laboratory | Marczewski J.,Polish Institute of Electron Technology | Kopyt P.,Institute of Radioelectronics | Dyakonova N.,CNRS Charles Coulomb Laboratory | And 7 more authors.
IRMMW-THz 2015 - 40th International Conference on Infrared, Millimeter, and Terahertz Waves | Year: 2015

Phenomena of the radiation coupling to the field effect transistors based terahertz detectors is studied. We show that in the case of flat metallic antennas important part of radiation, instead coupling to the transistors, is coupled to the substrate leading to losses. Experimental and theoretical investigations of the responsivity versus substrate thickness are performed. They clearly show how to minimize the losses by the detector substrate thinning. © 2015 IEEE.


But D.B.,CNRS Charles Coulomb Laboratory | Coquillat D.,CNRS Charles Coulomb Laboratory | Dyakonova N.,CNRS Charles Coulomb Laboratory | Teppe F.,CNRS Charles Coulomb Laboratory | And 4 more authors.
2016 21st International Conference on Microwave, Radar and Wireless Communications, MIKON 2016 | Year: 2016

Experimental and theoretical investigations of the influence of substrate thickness on the performance of Si field effect transistor terahertz detectors are presented.. We show that in the case of planar metal antennas a significant portion of incoming radiation, instead of being coupled to the transistors, may be coupled to the substrate leading to important responsivity losses..The ways of avoiding these losses are discussed. © 2016 IEEE.


Kolakowski J.,Institute of Radioelectronics | Berezowska M.,Institute of Radioelectronics | Michnowski R.,Institute of Radioelectronics | Radecki K.,Institute of Radioelectronics | Malicki L.,Knowledge Society Association
Proceedings of the 2015 IEEE 8th International Conference on Intelligent Data Acquisition and Advanced Computing Systems: Technology and Applications, IDAACS 2015 | Year: 2015

The paper contains a description of a measurement system intended for gathering data typically used for evaluation of elderly persons mobility and behaviour. The measurements are carried out with MEMS sensors assembled in the mobile device worn by the monitored person. Results of measurements are sent over wireless link to recording nodes for analysis. The paper describes system design and presents examples of recorded data. Proposals of system usage for mobility and behaviour investigation are also presented and discussed. © 2015 IEEE.


Kossakowski P.,Warsaw University of Life Sciences | Bilski P.,Warsaw University of Life Sciences | Bilski P.,Institute of Radioelectronics
Proceedings of the 2015 IEEE 8th International Conference on Intelligent Data Acquisition and Advanced Computing Systems: Technology and Applications, IDAACS 2015 | Year: 2015

In this paper the application of Self-Organizing Maps to analyze the stock market data is presented. The impact of this type of the neural network on the performance of investment strategies is discussed. The considered characteristics include the size of the network based on the average number of learning patterns per neuron, conscience mechanism, method of weights update and learning coefficient. Performance of each network configuration is verified against the simple investment strategy, which on the basis of average Rate of Return (RoR) generates 'buy' and 'sell' signals. Results show that SOMs with the conscience mechanism performs better than the counterpart without it. © 2015 IEEE.


Kopye P.,Institute of Radioelectronics | Gwarek W.K.,Institute of Radioelectronics
IEEE MTT-S International Microwave Symposium Digest | Year: 2010

For years the positive effect of employing microwave energy in material processing has been observed in multiple reactions, where it leads to shorter processing time in comparison to the conventional methods. However, in a large part of the reported experiments over-size, low-Q cavities and low spectrum purity magnetrons were employed as microwave power applicators and power sources respectively. This raises some doubts regarding the accuracy of described results as the equipment makes it particularly difficult to precisely control crucial parameters of such processes. The authors of this paper suggest a more systematic approach based on high-Q, singlemode microwave power applicators aimed at formulating a oneto- one relationship between the individual microwave-assisted process characteristics and the properties of the final product. An example TM0l0 cavity for sintering of silicon-based composites (e.g. Si-diamond) is designed and initially verified by means of coupled multiphysics thermodynamic-electromagnetic modeling. © 2010 IEEE.


Kozlowski E.,Central Institute for Labour Protection | Zera J.,Central Institute for Labour Protection | Zera J.,Institute of Radioelectronics | Zera J.,Warsaw University of Technology | And 2 more authors.
International Journal of Occupational Safety and Ergonomics | Year: 2011

In this study, change in A-weighted and 1/3-octave sound pressure levels (SPLs) was used to assess the influence of wearing earplugs by musicians on their musical performances. Seven soloists and 3 music assembles performed 4 pieces of music with musician's earplugs donned and doffed. They used silicon custom moulded earplugs with acoustic filters designed to attenuate sound by 9, 15 or 25 dB. Results showed that the use of earplugs affected the sound level and the spectrum of played sounds. This effect was the greatest for brass players. The difference between SPLs in high-frequency 1/3-octave bands and A-weighted SPLs with and without earplugs exceeded 5 and 15 dB, respectively. Similar changes for woodwind, percussion and string instruments were less noticeable than for brass instruments; they were more than 5 dB for 1/3-octave spectra and no more than 2 dB for A-weighted SPL.


Yavorskiy D.,University of Warsaw | Marczewski J.,Polish Institute of Electron Technology | Kucharski K.,Polish Institute of Electron Technology | Kopyt P.,Institute of Radioelectronics | And 5 more authors.
Photonics Letters of Poland | Year: 2012

A scanning device for imaging at THz frequencies was designed and constructed. The device comprised a 335~GHz source of radiation, an x-y-z translation stages, a number of optical elements and a detector. The detector was a silicon field-effect transistor supplied with a resonant antenna and a low-noise preamplifier. With a detector response of 10~V/W and a source power of 10~mW we could generate images in a DC mode with a speed limited only by the velocity of the stages movement. © 2012 PhotonicsSociety of Poland.


Kopyt P.,Institute of Radioelectronics | Zagrajek P.,Institute of Optoelectronics | Marczewski J.,Polish Institute of Electron Technology | Kucharski K.,Polish Institute of Electron Technology | And 4 more authors.
Microelectronics Journal | Year: 2014

In this paper an approach to analysis of responsivity of MOSFET-based detectors of THz radiation has been presented. The authors have analyzed the substrate modes that affect performance of antennas that are always used as a part of detecting structures, and should be accounted for by proper choice of the substrate geometry. Then, a methodology to combine extracted properties of an arbitrary antenna with properties of the transistor channel has been described and employed to estimate responsivity of a detector built of a particular MOSFET integrated with several antenna structures. Finally, example detectors were fabricated and measured using sub-THz radiation sources operating in the combined bandwidth 220-360 GHz. Measurement results were compared with predictions which lead to conclusions on possible levels of the impedance of the transistor channel at these frequencies. © 2014 Elsevier Ltd. All rights reserved.

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