Wyniki wyszukiwania - BazTech

1

Multipleksacja promieniowania THz z wykorzystaniem nie-poosiowych optycznych struktur dyfrakcyjnych

Komorowski Paweł

Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

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2022

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nr 4

523--526

PL

Powszechnie uważa się, że zakres THz będzie podstawą przyszłych sieci 6G i nie podlega wątpliwości, że konieczne jest opracowywanie rozwiązań zwiększających możliwości przesyłowe tego typu systemów. Przedstawione badania mają na celu eksplorację możliwości multipleksacji terahercowych kanałów transmisji danych z wykorzystaniem struktur dyfrakcyjnych, przekierowujących promieniowanie w wiele punktów ogniskowych. W celu zaprojektowania tego typu elementów, opracowano i zaimplementowano algorytmy optymalizacyjne (w tym unikatowy algorytm, bazujący na splotowej dyfrakcyjnej sieci neuronowej). Opracowane struktury mogą z powodzeniem być stosowane dla dużego zakresu częstotliwości terahercowych i sub-terahercowych, umożliwiając tym samym multipleksację kanałów transmisji danych w przyszłych sieciach telekomunikacyjnych, niezależnie od wykorzystywanego przez nie pasma.

EN

It is commonly believed, that THz waves will be the base of the future 6G telecommunication systems and all development of methods increasing the bandwidth of those systems is necessary. The novel solutions for the designing and optimization, based on the diffractive optical elements for the THz spectral range, have been proposed in this work. Described structures allow redirecting THz radiation into multiple focal points, also with frequency separation. The design and optimization algorithms for the diffractive elements have been developed and implemented (including a unique method, based on the convolutional diffractive neural network). Designed structures can work in a wide range of terahertz and sub-terahertz radiation. Therefore, they can be considered an appealing solution, regardless of the band, used by future telecommunication systems.

2

Information fusion method of multichannel nanosensors based on neural network

Li Chaoke

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2022

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Vol. 70, nr 2

art. no. e140258

EN

Information fusion approaches have been commonly used in multi sensor environments for the fusion and grouping of data from various sensors which is used further to draw a meaningful interpretation of the data. Traditional information fusion methods have limitations such as high time complexity of fusion processes and poor recall rate. In this work, a new multi-channel nano sensor information fusion method based on a neural network has been designed. By analyzing the principles of information fusion methods, the back propagation based neural network (BP-NN) is devised in this work. Based on the design of the relevant algorithm flow, information is collected, processed, and normalized. Then the algorithm is trained, and output is generated to achieve the fusion of information based on multi-channel nano sensor. Moreover, an error function is utilized to reduce the fusion error. The results of the present study show that compared with the conventional methods, the proposed method has quicker fusion (integration of relevant data) and has a higher recall rate. The results indicate that this method has higher efficiency and reliability. The proposed method can be applied in many applications to integrate the data for further analysis and interpretations.

3

Performance evaluation of UFMC-based VLC systems using a modified SLM technique

Mansour Shalaby E., Dessouky M., Hussin S.

Opto-Electronics Review

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2021

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Vol. 29, No. 3

85--90

EN

Universal filtered multi-carrier (UFMC) is being studied as the favourable waveforms supporting the visible light communication broadcasting systems. However, the UFMC system faces a serious performance degradation on the transmitter side due to its high peak-to-average power ratio (PAPR). High PAPR of the signal is an analytical intention parameter for mobile networks, and it is necessary to minimize it as much as possible. This paper focuses on the PAPR reduction of the UFMC scheme. An efficient hybrid method of the PAPR reduction has been proposed and analysed through the Matlab™ simulation. The proposed hybrid scheme consists of a mixture of the selected-mapping method and the discrete Hartley transform precoding for a UFMC system (SLM-DHT-P-UFMC). The simulation results show that the proposed hybrid system has a better PAPR reduction performance compared to traditional SLM-UFMC and DHT-P-UFMC systems. Hence, LM-DHT-P-UFMC is considered to be the suggested scheme in visible light communication broadcasting systems.

4

Optical multiple-image encryption in discrete multiple-parameter fractional Fourier transform scheme using complex encoding, theta modulation and spectral fusion

Luan Guangyu, Zhong Zhi, Shan Mingguang

Optica Applicata

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2021

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Vol. 51, nr 1

121--134

EN

We present a novel encryption method for multiple images in a discrete multiple-parameter fractional Fourier transform scheme, using complex encoding, theta modulation and spectral fusion. All pairs of original images are encoded separately into a complex signal. The spectrum of each complex signal can then be scattered into various positions in the spectral plane and multiplexed into one spectral image with a combination of theta modulation and spectral fusion. After Fourier transforming back to the spatial domain, the multiplexed signal is encrypted in the discrete multiple-parameter fractional Fourier transform domain. Information about the original images can only be successfully decrypted given the possession of all correct keys. The parameters of chaotic pixel scrambling for the proposed method enlarge the key space. Moreover, the proposed method solves the crosstalk problem of multiple images and improves the multiplexing capacity. Numerical simulations demonstrate the effectiveness of the proposed method.

5

Impact of Filter Characteristics and Optical Signal Parameters on Interchannel Crosstalk

Kowalczyk A., Perlicki K.

International Journal of Electronics and Telecommunications

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2014

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Vol. 60, No. 1

83-87

EN

In this paper we present analysis of the influence of filter characteristics of Wavelength Division Multiplexing network components and transmission parameters over inter-channel crosstalk for symmetric and asymmetric transmission. The simulation was carried out for bit rate 10 Gb/s, 40 Gb/sand 100 Gb/s considering the following modulations: DPSK, DQPSK and OOK. The obtained results show that OOK and DQPSK modulation are better than DPSK modulation in terms of crosstalk occurring during the transmission of signals in Wavelength Division Multiplexing systems.

6

Technologia xMAP® - nowatorska forma multipleksowania w diagnostyce i badaniach naukowych

Zborowski T.

Laboratorium - Przegląd Ogólnopolski

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2013

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nr 11-12

75--77

7

Optimistic Processing Protocol for Multiplexing in External PC Grids

Funo A., Higami Y., Kobayashi S.

Pomiary Automatyka Kontrola

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2010

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R. 56, nr 11

1378-1381

EN

In external PC grids, it is difficult to protect data from falsifications and analyses because the data is processed by unspecified hosts. In the past, to resolve this problem a concealing method for processing purposes (CMPP) has been proposed. Although CMPP can detect falsifications with high probability, it takes much time to process the whole program due to the majority vote. This paper proposes an optimistic processing protocol for multiplexing. In the proposed protocol, each host starts to execute its segment based on a result of a previous segment from only one host even if the result is not decided by a majority vote. The majority vote is done after results of other hosts arrive. Through simulation experiments, we show that the proposed scheme can improve processing time of programs efficiently.

PL

W zewnętrznych sieciach komputerów osobistych trudno jest zabezpieczyć dane przed ich fałszowaniem i analizowaniem, ponieważ dane są przetwarzane przez bliżej nieokreślone serwery. W przeszłości do rozwiązania tego problemu była proponowana metoda ukrywania problemu przy przetwarzaniu (CMPP). Metoda CMPP polega na podzieleniu programu na wiele segmentów, a te segmenty są przetwarzane na różnych serwerach, aby zapobiec wykonaniu niepożądanej analizy programu. Co więcej, aby wykryć fałszerstwa, metoda CMPP zawiera schemat multipleksowania który wykonuje identyczne segmenty na różnych serwerach równolegle i decyduje o wyniku przetwarzania metodą głosowania większościowego. Chociaż CMPP może wykryć fałszerstwa z wysokim prawdopodobieństwem, to jednak głosowanie większościowe wymaga długiego czasu przetworzenia całego programu. W artykule jest zaproponowany protokół optymistycznego przetwarzania do multipleksowania. W zaproponowanym protokole każdy serwer zaczyna wykonywać własny segment w oparciu o wyniki poprzedniego segmentu z jednego z serwerów, nawet jeżeli wynik nie jest potwierdzony przez głosowanie większościowe. Głosowanie większościowe jest wykonywane po nadejściu wyników z innych serwerów. Za pomocą eksperymentów symulacyjnych wykazano, że proponowany schemat może efektywnie skrócić czas przetwarzania programów.

8

Video-rate multiplexed driving scheme for passive antiferroelectric liquid crystal displays

Quintana X., Castillo P. L., Otón J. M., Bennis N., Lara A., Urruchi V., Dąbrowski R.

Opto-Electronics Review

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2004

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Vol. 12, No. 3

291-297

EN

Antiferroelectric liquid crystals have been applied to high-end multiplexed displays. The interest on these materials chiefly comes up from their capability of being multiplex addressed with no need of active matrices. Antiferroelectric grey levels arise from a double symmetric hysteresis loop that can be stabilized by a constant holding voltage. Driving schemes are compatible with passive multiplexing, but limitations appear when the multiplexing rate increases. To avoid these limitations, new driving schemes for high multiplexing level at video rate have been designed. The problem of accumulated voltage on bias level arising from data voltages is tackled as well.