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Comparative Study of PSO and CMA-ES Algorithms on Black-box Optimization Benchmarks, Journal of Telecommunications and Information Technology, 2018, nr 4
Get PDFNumerous practical engineering applications can be formulated as non-convex, non-smooth, multi-modal and ill-conditioned optimization problems. Classical, deterministic algorithms require an enormous computational effort, which tends to fail as the problem size and its complexity increase, which is often the case. On the other hand, stochastic, biologically-inspired techniques, designed for global optimum calculation, frequently prove successful when applied to real life computational problems. While the area of bio-inspired algorithms (BIAs) is still relatively young, it is undergoing continuous, rapid development. Selection and tuning of the appropriate optimization solver for a particular task can be challenging and requires expert knowledge of the methods to be considered. Comparing the performance of viable candidates against a defined test bed environment can help in solving such dilemmas. This paper presents the benchmark results of two biologically inspired algorithms: covariance matrix adaptation evolution strategy (CMA-ES) and two variants of particle swarm optimization (PSO). COCO (COmparing Continuous Optimizers) – a platform for systematic and sound comparisons of real-parameter global optimization solvers was used to evaluate the performance of CMA-ES and PSO methods. Particular attention was paid to the efficiency and scalability of both techniques
Instytut Radiotechniczny 1928–1934, Telekomunikacja i Techniki Informacyjne, 2018, nr 1-2
Get PDF90 lat temu założona została pierwsza polska jednostka badawcza w dziedzinie radiotechniki – Instytut Radiotechniczny w Warszawie. Artykuł przedstawia historię powstania tej pionierskiej instytucji. Omówiona została sytuacja polskiej radiotechniki po 1918 r., inicjatorzy i proces organizacji Instytutu Radiotechnicznego oraz jego struktura i działalność w latach 1929–1934
Aktywność Instytutu Łączności na rzecz rozwoju nowoczesnych systemów i technik satelitarnych, Telekomunikacja i Techniki Informacyjne, 2018, nr 1-2
Get PDFOd momentu przystąpienia Polski do Europejskiej Agencji Kosmicznej, zainteresowanie krajowych firm i instytucji segmentem technik i systemów satelitarnych znacząco wzrosło. W niniejszym artykule opisano działania Instytutu Łączności – Państwowego Instytutu Badawczego (IŁ) na tym polu na przestrzeni kilku ostatnich lat. Poszczególne części publikacji poświęcone są osobnym obszarom tematycznym podejmowanym przez IŁ, w tym: badaniom dostępności sygnałów GNSS na terenie Polski, standaryzacji i rozwojowi nowego systemu łączności na morzu VDES, pracom związanym z opracowaniem koncepcji polskiego satelity AIS/VDES oraz metrologii czasu
Radio Vision Systems Ensuring Movement Safety for Ground, Airborne and Sea Vehicles, Journal of Telecommunications and Information Technology, 2018, nr 4
Get PDFThis article presents the features of an all-weather radio vision system (RVS) ensuring the safety of movement of ground, airborne and sea vehicles and automation of vehicle traffic control under limited or non-existent visibility conditions. New and promising RVS applications in the aviation and rail transport sectors are presented. The potential use of RVS based on an interferometric radar with aperture synthesis, capable of estimating the position of ice fields and the height of icebergs is considered as well
Swarm Intelligence-based Partitioned Recovery in Wireless Sensor Networks, Journal of Telecommunications and Information Technology, 2018, nr 3
Get PDFThe failure rate of sensor nodes in Heterogeneous Wireless Sensor Networks is high due to the use of low battery-powered sensor nodes in a hostile environment. Networks of this kind become non-operational and turn into disjoint segmented networks due to large-scale failures of sensor nodes. This may require the placement of additional highpower relay nodes. In this paper, we propose a network partition recovery solution called Grey Wolf, which is an optimizer algorithm for repairing segmented heterogeneous wireless sensor networks. The proposed solution provides not only strong bi-connectivity in the damaged area, but also distributes traffic load among the multiple deployed nodes to enhance the repaired network’s lifetime. The experiment results show that the Grey Wolf algorithm offers a considerable performance advantage over other state-of-the-art approaches
A New Code Family for QS-CDMA Visible Light Communication Systems, Journal of Telecommunications and Information Technology, 2018, nr 3
Get PDFVisible light communication (VLC) is a promising technology for wireless communication networks. Optical code division multiple access (OCDMA) is a strong candidate for VLC-based applications. The predominant source of bit error in OCDMA is the multiple access interference (MAI). To eliminate MAI in synchronous OCDMA, zero cross correlation (ZCC) codes have been proposed. However, synchronization problems and multipath propagation introduce relative non-zero time delays. Therefore, the zero correlation zone (ZCZ) concept was introduced. In this paper, we propose a new method for generating ZCC codes. The proposed construction can accommodate any number of users with flexible Hamming weight. The numerical results obtained show that the proposed codes significantly reduce MAI, compared to ZCC, as well as ZCZ codes
Współpraca Instytutu Łączności z wybranymi partnerami zagranicznymi, Telekomunikacja i Techniki Informacyjne, 2018, nr 1-2
Get PDFArtykuł przedstawia pokrótce historię międzynarodowej współpracy Instytutu Łączności – Państwowego Instytutu Badawczego (IŁ) w wybranych dziedzinach, ze szczególnym uwzględnieniem najistotniejszych międzynarodowych konferencji, których był inicjatorem i organizatorem oraz w zakresie współpracy w ramach najważniejszych organizacji międzynarodowych (ITU, CEPT, IEC, IALA-IMO, ETSI, URSI, IEEE-EMCS, ICTP, OWŁ/RWPG)
Measurements and Statistical Analysis for Assessment of Availability of Mobile Network Services, Journal of Telecommunications and Information Technology, 2018, nr 2
Get PDFAvailability is an essential feature of telecommunication services. It influences the quality of experience (QoE) associated with individual networks and with the services offered. Therefore, it needs to be allowed for at each level of network design, and has to be controlled at the operation stage. This is achieved by means of various mathematical and numerical tools. In this project listening quality and speech level, which are quality-related features of mobile network services, are measured and analyzed with the Monte Carlo simulation method. Measurements are taken with assistance of the Diversity Benchmarker, a reliable device designed for mobile network testing. Finally, results obtained are compared to assess the applicability of the Monte Carlo method
Performance Analysis of SPSK with Dual Polarized Transmit Antennas over Rayleigh Fading Channel, Journal of Telecommunications and Information Technology, 2018, nr 1
Get PDFIn this paper, the Space Polarization Shift Keying (SPSK) system, which is an extended version of Space Shift Keying (SSK) and includes both space and polarization dimensions with dual polarized antennas, is studied. The capacity and error probability analysis of SPSK for different polarization configurations are dealt with over the Rayleigh fading channel with a rich scattering environment. The analysis conducted shows that the SPSK with a dual polarized antenna (DP) offers better results than SPSK with a single orthogonal polarized antenna SPSK(SP), under non-LOS conditions. SPSK(DP) outperforms SSK by 4.2 dB over the correlated Rayleigh fading channel at 3 bits/s/Hz
Incoherent Discriminative Dictionary Learning for Speech Enhancement, Journal of Telecommunications and Information Technology, 2018, nr 3
Get PDFSpeech enhancement is one of the many challenging tasks in signal processing, especially in the case of nonstationary speech-like noise. In this paper a new incoherent discriminative dictionary learning algorithm is proposed to model both speech and noise, where the cost function accounts for both “source confusion” and “source distortion” errors, with a regularization term that penalizes the coherence between speech and noise sub-dictionaries. At the enhancement stage, we use sparse coding on the learnt dictionary to find an estimate for both clean speech and noise amplitude spectrum. In the final phase, the Wiener filter is used to refine the clean speech estimate. Experiments on the Noizeus dataset, using two objective speech enhancement measures: frequency-weighted segmental SNR and Perceptual Evaluation of Speech Quality (PESQ) demonstrate that the proposed algorithm outperforms other speech enhancement methods tested