Wyniki wyszukiwania - BazTech

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Coded GFDM with decision feedback equaliser for enhanced performance in underwater wireless optical communication

Hema R., Ananthi A., Diana D. C.

Opto-Electronics Review

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2024

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Vol. 32, No. 1

art. no. e148697

EN

Underwater wireless optical communication is the best alternative for many applications especially for high bandwidth data communication between underwater objects and vehicles. The implementation of coding scheme along with advanced modulation technique and equalisation methods is identified as a key research scope for enhancing the performance of the system. In this paper, the coded generalised frequency division multiplexing (GFDM) technology is employed to provide high-data rates and less out-of-band emission. The Bose-Chaudhuri-Hocquenghem (BCH) and Reed-Solomon (RS) coding schemes along with equalisation techniques namely normalised least mean square (NLMS)-based decision feedback equalisers (DFE), minimum mean square error (MMSE) and zero forcing (ZF) are utilized to reduce inter symbol interference (ISI). The bit error rate (BER) performance is evaluated in the presence of pointing error (PE) and turbulence using Monte Carlo channel modelling simulations. The results showed that RS coding with NLMS-DFE outperforms other techniques and achieves a BER of roughly 10⁻⁵ with a signal-to-noise ratio levels below 20 dB. The simulation results demonstrate that RS code with 15 total symbols per code word and 3 data symbols, i.e., RS (15, 3) and BCH code with 31 total symbols in a code word and 6 data symbols, i.e., BCH (31, 6) provided the best error performance among other coding schemes employed. It is inferred that RS (15, 3) coded 2 × 2 multiple input multiple output systems with NLMS-DFE achieved a BER value of 1.1925 × 10⁻⁵ at 11 dB which is 16 dB less than uncoded system. Thus, the coded GFDM improves overall BER performance and has the potential to provide higher reliability for internet of underwater things (IoUT) applications.

2

Overlapped filtered multitone modulation and its optimization on VLIW DSP

Silhavy P., Krajsa O., Systel P., Koutny M.

Przegląd Elektrotechniczny

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2011

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R. 87, nr 12a

145-149

EN

In recent years, the multicarrier modulations (MCM) have been applied to wire and wireless transmission systems. MCM enable a nearperfect utilization of the provided frequency band on metallic cables and they also effectively eliminate multipath propagation in terrestrial transmission. They are mainly the implementations called Discrete MultiTone (DMT) and Orthogonal Frequency Division Multiplexing (OFDM). These approaches have also disadvantages, which have led to seeking new approaches to the implementation of the MCM modulation scheme. One of them is the Filtered MultiTone Modulation (FMT). In the article, the channel equalization in overlapped and non-overlapped FMT modulation will be compared. The optimal implementation of FMT on the VLIW DSP will be introduced in the second part.Optimized implementation of filter bank with the help of parallel processing is described, and also frame writing/reading and its synchronization are introduced.

PL

W ostatnich latach, w modulacjach multicarrier (MCM) zostały zastosowane systemy transmisji przewodowej i bezprzewodowej. MCM umożliwiają niemal perfekcyjne wykorzystanie pasma częstotliwości przewidziane w kablach a również skutecznie wyeliminować wielodrogowość w transmisji naziemnej. Są to przede wszystkim implementacje o nazwie Discrete wielotonowy (DMT) i Orthogonal Frequency Division Multiplexing (OFDM). Metody te mają także wady, które doprowadziły do poszukiwania nowych sposobów podejściacia do wdrożenia systemu modulacji MCM. Jednym z nich jest filtrowane wielotonowe modulacji (FMT). W drugiej częścici artykułu została opisana optymalna implementacja modulacji FMT. Wykorzystano bank filtrów z równoległym przetwarzaniem, oraz odpowiednie ramki zapisu/odczytu oraz synchronizacji.

3

Środowiskowa ocena oddziaływania chłodziarko-zamrażalek w procedurze ekoprojektowania sprzętu AGD

Lewicki R., Kurczewski P.

Inżynieria i Aparatura Chemiczna

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2011

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Nr 2

40-41

PL

W artykule przedstawiono wyniki oddziaływania chłodziarko-zamrażarek na środowisko w ujęciu cyklu ich istnienia. Ocena metodą LCA została przeprowadzona za pomocą programu Sima Pro 7 przy wykorzystaniu metodyki Eco-indicator 99. Analizę przeprowadzono dla wszystkich etapów cyklu życia. Uzyskane wyniki umożliwiły identyfikację dominujących, pod względem poziomu wywieranego oddziaływania, etapów cyklu życia chłodziarko-zamrażarki.

EN

The results of LCA analysis are presented in the paper. A refrigerator was taken as the object in the whole life cycle. Sima Pro 7 and Eco-indicator 99 software were used for calculations. Every stage of life cycle was considered. Results enabled one to indicate the stages of life cycle (material and processes) that impact decidedly on the environment.

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Concurrent engineering and DFMA approaches on the development of automotive panels and doors

Krumenauer F. Z., Matayoshi C. T., da Silva I. B., Filho M. S., Batalha G. F.

Journal of Achievements in Materials and Manufacturing Engineering

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2008

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Vol. 31, nr 2

690-698

EN

Purpose: The automotive industry, in countries such as Brazil, China and India, in contrast to the North American and European markets, is in full expansion. Due to the huge competition in the globalized automotive market, such countries face a challenge to continue this expansion. Especially important in order to win this battle, will be their capacities to release new products in the market faster than their competitors and with more cost efficiency, making an appropriate use of tools such as total quality management, concurrent engineering and increasing the use of innovative concepts in production and logistics [1,2]. Design/methodology/approach: According with the expose above, the aim of this work was to develop DFMA tools for an industrial real case. There several tools that could be included in the Design for Excellence (DFX) methodologies. Initially, two of those can be outstand here: Design For Manufacturing (DFM) and Design For Asse. Findings: In terms of the press shop facilities of the plant the main results, were: layout optimization, press line automation feasibility, reduced setup and increased productivity, improved racks logistic, reduced overhead, reduced stamped part scraps and resources with mechanical presses selling. In terms of the planning activities, the main results were: reduce time to market, reduce press shop machinery and die stamping investments and reduce indirect cost. Practical implications: The main proposal of concurrent engineering is to shorten a product development time through a simultaneous time implementation of the several stages of the engineering activity in parallel and under a concurrent mode offering all information required by all elements of the product life cycle. Originality/value: This paper reviews fundamental concepts in concurrent engineering and DFX aiming to discuss criteria of assembly and manufacturability regarding the development of automotive panels and doors. A more detailed presentation of the Finite Element Analysis (FEA) and Computer Aided Design (CAD) results obtained during the practical industrial case of auto body panel development are not presented here due to data confidentiality and page limitation.