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Wyświetlanie 1-12 z 12
Tytuł:
A Comparative Study of Various Edge Detection Techniques for Underwater Images
Autorzy:
Awalludin, Ezmahamrul Afreen
Arsad, Tengku Noorfarahana T.
Yussof, Wan Nural Jawahir Hj Wan
Bachok, Zainudin
Hitam, Muhammad Suzuri
Powiązania:
https://bibliotekanauki.pl/articles/2058499.pdf
Data publikacji:
2022
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
edge detection
mean square error
median filtering
peak signal to noise
wiener filtering
Opis:
Nowadays, underwater image identification is a challenging task for many researchers focusing on various ap plications, such as tracking fish species, monitoring coral reef species, and counting marine species. Because underwater im ages frequently suffer from distortion and light attenuation, pre-processing steps are required in order to enhance their quality. In this paper, we used multiple edge detection techniques to determine the edges of the underwater images. The pictures were pre-processed with the use of specific techniques, such as enhancement processing, Wiener filtering, median filtering and thresholding. Coral reef pictures were used as a dataset of underwater images to test the efficiency of each edge detection method used in the experiment. All coral reef image datasets were captured using an underwater GoPro camera. The performance of each edge detection technique was evaluated using mean square error (MSE) and peak signal to noise ratio (PSNR). The lowest MSE value and the highest PSNR value represent the best quality of underwater images. The results of the experiment showed that the Canny edge detection technique outperformed other approaches used in the course of the project.
Źródło:
Journal of Telecommunications and Information Technology; 2022, 1; 23--33
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multi-layered Bayesian Neural Networks for Simulation and Prediction Stress-Strain Time Series
Autorzy:
Krok, A.
Powiązania:
https://bibliotekanauki.pl/articles/308596.pdf
Data publikacji:
2015
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
Bayesian neural networks
Kalman filtering
Opis:
The aim of the paper is to investigate the differences as far as the numerical accuracy is concerned between feedforward layered Artificial Neural Networks (ANN) learned by means of Kalman filtering (KF) and ANN learned by means of the evidence procedure for Bayesian technique. The stress-strain experimental time series for concrete hysteresis loops obtained by the experiment of cyclic loading is presented as considered example.
Źródło:
Journal of Telecommunications and Information Technology; 2015, 3; 45-51
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Face Tracking and Recognition with the Use of Particle-Filtered Local Features
Autorzy:
Stasiak, Ł. A.
Pacut, A.
Powiązania:
https://bibliotekanauki.pl/articles/308537.pdf
Data publikacji:
2010
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
biometrics
face recognition
particle filtering
video analysis
Opis:
A consistent particle filtering-based framework for the purpose of parallel face tracking and recognition from video sequences is proposed. A novel approach to defining randomized, particle filtering-driven local face features for the purpose of recognition is proposed. The potential of cumulating classification decisions based on the proposed feature set definition is evaluated. By applying cumulation mechanisms to the classification results determined from single frames and with the use of particle-filtered features, good recognition rates are obtained at the minimal computational cost. The proposed framework can operate in real-time on a typical modern PC. Additionally, the application of cumulation mechanisms makes the framework resistant to brief visual distortions, such as occlusions, head rotations or face expressions. A high performance is also obtained on low resolution images (video frames). Since the framework is based on the particle filtering principle, it is easily tunable to various application requirements (security level, hardware constraints).
Źródło:
Journal of Telecommunications and Information Technology; 2010, 4; 26-36
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Frequency Offset Compensation for OFDM Systems Using a Combined Autocorrelation and Wiener Filtering Scheme
Autorzy:
Ramadan Ali, A.
Khanzada, T. J.
Omar, A.
Powiązania:
https://bibliotekanauki.pl/articles/308065.pdf
Data publikacji:
2010
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
channel characterization
frequency offset
OFDM measurement
Wiener filtering
Opis:
One of the orthogonal frequency division multiplexing (OFDM) system disadvantages is its sensitivity to frequency offset and phase noise, which lead to losing the orthogonality between the subcarriers and thereby degrade the system performance. In this paper a joint scheme for frequency offset and pilot-based channel estimation is introduced in which the frequency offset is first estimated using an autocorrelation method, and then is fined further by applying an iterative phase correction by means of pilot-based Wiener filtering method. In order to verify the capability of the estimation algorithm, the scheme has been implemented and tested using a real measurement system in a multipath indoor environment. The results show the algorithm capability of compensating for the frequency offset with different transmission and channel conditions.
Źródło:
Journal of Telecommunications and Information Technology; 2010, 1; 40-47
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Web Services Efficiency in Disadvantaged Environment
Autorzy:
Śliwa, J.
Podpasek, T.
Amanowicz, M.
Powiązania:
https://bibliotekanauki.pl/articles/309550.pdf
Data publikacji:
2011
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
compression
filtering
image resize
SOA in tactical networks
Opis:
The article presents results of web services (WSs) efficiency tests carried out in the testbed emulating disadvantaged network environment. The authors discuss the advantage of different WS adaptation techniques that allow to minimize the XML message size (i.e. compression, filtering and binary coding) and the size of JPEG image attachment (i.e., resolution reduction, decreasing colour depth, JPEG compression). The presented results show the efficiency of selected methods that adapt the web services realization to the possibilities of the network. The article is summarized by conclusions and recommendations in terms of sending XML SOAP messages in disadvantaged networks.
Źródło:
Journal of Telecommunications and Information Technology; 2011, 1; 62-68
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Enhancing Moon Crescent Visibility Using Contrast-Limited Adaptive Histogram Equalization and Bilateral Filtering Techniques
Autorzy:
Yussof, Wan Nural Jawahir Hj Wan
Man, Mustafa
Umar, Roslan
Zulkeflee, Ahmad Najmuddin
Awalludin, Ezmahamrul Afreen
Ahmad, Nazhatulshima
Powiązania:
https://bibliotekanauki.pl/articles/2058508.pdf
Data publikacji:
2022
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
bilateral filtering
CIELab
CLAHE
image enhancement
moon crescent
Opis:
Image enhancement is becoming increasingly im portant with the advancement of space exploration techniques and the technological development of more durable and sci entifically sound observatories equipped with more powerful telescopes. The enhancement of images helps astronomers an alyze the results and act toward determining the dates of religious festivals. This work describes a technique known as contrast-limited adaptive histogram equalization (CLAHE) with grayscale contrast enhancement and bilateral filtering. We apply CLAHE on the L component of the CIE-Lab color space to adjust lightness contrast. Subsequently, grayscale contrast enhancement is performed to increase the visibility of the moon crescent. Noise caused by grayscale contrast en hancement is reduced using bilateral filtering. Two quantitative measures are selected (PSNR and MSE) to show the visual improvement achieved by the proposed algorithm.
Źródło:
Journal of Telecommunications and Information Technology; 2022, 1; 3--13
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design of a Microstrip Filtering Antenna for 4G and 5G Wireless Networks
Autorzy:
Boddu, Ramesh
Deb, Arindam
Roy, Jibendu Sekhar
Powiązania:
https://bibliotekanauki.pl/articles/24200731.pdf
Data publikacji:
2023
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
elliptical microstrip patch antenna
filtering antenna
hairpin bandpass filter
Opis:
The filtering antenna provides both radiation and filtering features and is an important component for the RF front-end of wireless devices. The main function of a filtering antenna is to reject out-of-band signals, thus reducing the interference from adjacent channels. The aim of the present work is to design a 2.6 GHz microstrip filtering antenna for 4G and 5G global mobile services. The filtering antenna is designed using a hairpin bandpass filter integrated with an elliptical microstrip aerial. Good impedance matching is obtained by using appropriate dimensions of the hairpin bandpass filter. The 10 dB return loss bandwidth of the filtering antenna is approx. 5.7%, with the maximum gain for the elliptical filtering antenna of approx. 2.2 dB. Good agreements between the measured and simulated results are obtained for the proposed filtering antenna and the bandwidth covers almost the entire 2.6 GHz band.
Źródło:
Journal of Telecommunications and Information Technology; 2023, 2; 78--83
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Towards a Unified Architecture of Knowledge Management System for a Research Institute
Autorzy:
Sobieszek, J.
Powiązania:
https://bibliotekanauki.pl/articles/307956.pdf
Data publikacji:
2008
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
creativity support
knowledge management
model-driven software development
tagged collaborative filtering
Opis:
This paper presents some elements of architecture of planned knowledge management system dedicated to research institutions. Main contributions include social extension of the idea of adaptive hermeneutic agent and preliminary implementation of domain specific language for development of knowledge management systems. Work described here concentrated on practical verification of viability of proposed ideas and took form of a prototype software system, which can be used by a group of researchers to easily find and recommend relevant information.
Źródło:
Journal of Telecommunications and Information Technology; 2008, 4; 54-59
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Linear quadratic power control for CDMA systems
Autorzy:
Anderson, M.D.
Perreau, S.
White, L.B.
Powiązania:
https://bibliotekanauki.pl/articles/307733.pdf
Data publikacji:
2003
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
CDMA
CDMA systems
power control
Kalman filtering
channel estimation
linear quadratic control systems
Opis:
In this paper, we present a robust decentralized method for jointly performing channel estimation and closed loop power control for the reverse link of CDMA networks. Our method, based on linear quadratic Gaussian (LQG) control systems theory and Kalman filtering, does not require any training symbols for channel or signal to interference ratio (SIR) estimation. The main interest of this new scheme is that it improves the performance of current SIR based power control techniques while avoiding the problem of power escalation, which is often observed in current systems.
Źródło:
Journal of Telecommunications and Information Technology; 2003, 2; 48-54
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Novel Kernel Algorithm for Finite Impulse Response Channel Identification
Autorzy:
Fateh, Rachid
Darif, Anouar
Boumezzough, Ahmed
Safi, Said
Frikel, Miloud
Powiązania:
https://bibliotekanauki.pl/articles/24200741.pdf
Data publikacji:
2023
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
finite impulse response
kernel adaptive filtering
kernel recursive projection identification
nonlinear system identification
Opis:
Over the last few years, kernel adaptive filters have gained in importance as the kernel trick started to be used in classic linear adaptive filters in order to address various regression and time-series prediction issues in nonlinear environments.In this paper, we study a recursive method for identifying finite impulse response (FIR) nonlinear systems based on binary-value observation systems. We also apply the kernel trick to the recursive projection (RP) algorithm, yielding a novel recursive algorithm based on a positive definite kernel. For purposes, our approach is compared with the recursive projection (RP) algorithm in the process of identifying the parameters of two channels, with the first of them being a frequency-selective fading channel, called a broadband radio access network (BRAN B) channel, and the other being a a theoretical frequency-selective channel, known as the Macchi channel. Monte Carlo simulation results are presented to show the performance of the proposed algorithm.
Źródło:
Journal of Telecommunications and Information Technology; 2023, 2; 84--93
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Image Preprocessing for Illumination Invariant Face Verification
Autorzy:
Leszczyński, M.
Powiązania:
https://bibliotekanauki.pl/articles/308517.pdf
Data publikacji:
2010
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
DLDA
face verification
histogram normalization
homomorphic filtering
illumination normalization
LDA
PCA
preprocessing techniques
quotient image
retinex
Opis:
Performance of the face verification system depend on many conditions. One of the most problematic is varying illumination condition. In this paper 14 normalization algorithms based on histogram normalization, illumination properties and the human perception theory were compared using 3 verification methods. The results obtained from the experiments showed that the illumination preprocessing methods significantly improves the verification rate and it's a very important step in face verification system.
Źródło:
Journal of Telecommunications and Information Technology; 2010, 4; 19-25
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Remedies to Thermal Radiation in Fused Silica Optical Fibers
Autorzy:
Borzycki, Krzysztof
Jaworski, Marek
Kossek, Tomasz
Powiązania:
https://bibliotekanauki.pl/articles/2200964.pdf
Data publikacji:
2023
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
attenuation testing
fire resistant fiber optic cable
fire test
fused silica optical fiber
incandescent emission
interference filtering
Opis:
During fire incidents, optical fibers located with-in a fire-resistant cable are usually exposed to temperatures of 800◦C to 1000◦C. Hot fibers generate narrowband thermal (incandescent) radiation and collect broadband thermal radiation originating from the heated surroundings. The power of the second component, initially negligible, increases with time due to the rising number of fiber cracks and other defects acting as couplers for external radiation. Thermal radiation may interfere with fiber attenuation measurements performed during a fire test, but is rather unlikely to prevent data transmission with typical GbE and 10 GbE transceivers during a fire. This problem may be remedied by combining the following methods: using single mode fibers instead of multimode fibers, using bandpass filters to block thermal radiation, and selecting proper transmitter power, wavelength and photodetector.
Źródło:
Journal of Telecommunications and Information Technology; 2023, 1; 88--96
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-12 z 12

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