In the presented work we define a class of error-correcting codes based on incidence vectors of projective geometries, including the necessary basis of coding theory and projective geometries. A detailed calculation i...
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In the presented work we define a class of error-correcting codes based on incidence vectors of projective geometries, including the necessary basis of coding theory and projective geometries. A detailed calculation is performed to show the dimension of these codes. In conclusion we concern ourselves with majority decoding. This work is a summary of the results of some known authors engaged in this field. We continue on some of these results and we present evidence of some of the statements, which have been proven differently by other authors.
Práce se zabývá výběrem a následným ověřením funkčnosti samoopravného kódu vhodného pro zabezpečení proti shlukujícím se chybám. Nejprve je pod&#...
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Práce se zabývá výběrem a následným ověřením funkčnosti samoopravného kódu vhodného pro zabezpečení proti shlukujícím se chybám. Nejprve je podán rozbor protichybového kódového systému a požadavky kladené na něj. Dále je uveden přehled a vlastnosti často používaných kódů. Poté se zaměřuje na podrobný popis Fireova, Hammingova a dvou BCH kódů. Po zdůvodnění výběru právě Hammingova kódu je popisováno odzkoušení funkčnosti protichybového systému v prostředí MathCad.
This paper reports a new design of optical time-division multiplexed (OTDM) systems that possess a functionality of simultaneous time demultiplexing and wavelength multicasting based on the cascaded four-wave mixing i...
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This paper reports a new design of optical time-division multiplexed (OTDM) systems that possess a functionality of simultaneous time demultiplexing and wavelength multicasting based on the cascaded four-wave mixing in a dispersion-flattened highly nonlinear photonic crystal fiber (DF-HNL-PCF). A module of OTDM demultiplexing and wavelength multicasting can be feasibly implemented by using a 3 dB optical coupler, a high-power erbium-doped fiber amplifier, a short-length DF-HNL-PCF, and a wavelength demultiplexer in the simple configuration. We also carry out an experiment on the proposed system to demonstrate the 100-10 Gbit s(-1) OTDM demultiplexing with wavelength conversion simultaneously at 4 multicast wavelengths. It is shown that error-free wavelength multicasting is achieved on two wavelength channels with the minimum power penalty of 3.2 dB relative to the 10 Gbit s(-1) back-to-back measurement, whereas the bit error rates of other two multicasting channels are measured to be about 10(-6)-10(-5). Moreover, we propose the use of a proper error-correcting code to improve the multicasting performance of such an OTDM system, and our work reveals that the resulting system can theoretically support error-free multicasting of the OTDM-demultiplexed signal on four wavelength channels.
The Gilbert channel model is applied to the multi-level decision feedback equalization (MDFE) detection scheme for digital magnetic recording channel. Model parameters are derived from simulation results. It is found ...
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The Gilbert channel model is applied to the multi-level decision feedback equalization (MDFE) detection scheme for digital magnetic recording channel. Model parameters are derived from simulation results. It is found that the MDFE channel can be modeled by the Gilbert channel model accurately. The model is further used to evaluate the performance after errorcorrectingcode (ECC) of the MDFE read channel with various ECC configurations. It is concluded that better performance is achieved with powerful ECC and less levels of interleaving.
In digital VCRs for home use, the video signal for each field is recorded on multiple tracks. Thus, it is difficult to reproduce the video signal smoothly in high-speed trick playback, where the signal is restored by ...
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In digital VCRs for home use, the video signal for each field is recorded on multiple tracks. Thus, it is difficult to reproduce the video signal smoothly in high-speed trick playback, where the signal is restored by scanning across the tracks. This paper intends to realize a satisfactory high-speed reproduction, and discusses the improvement of the head scanning trajectory, a high-speed trick playback error-control method, and a data coding method for the highspeed trick playback. In the base-band recording VCR, there is a problem that the fixed position of the image frame cannot be restored in integer-multiple speed playback. In order to cope with this problem, a method to adjust the drum rotation speed is considered, and the relation between the variation of the drum rotation and the period of the image presentation is derived. In the high-speed playback, only the C1 code can be restored among the error-correcting codes. For this problem, it is shown that the C3 code can be added and the error-correcting capability can be improved when a data area for high-speed trick playback is provided as in the bit-stream recording VCR. The requantization coding and the data-division coding methods are proposed as data coding methods for the high-speed trick playback. The effectiveness of those methods is demonstrated by image simulation. (C) 1997 Scripta Technica, Inc.
In the ATM system, all multimedia information, such as voice, picture and data, is divided into packets with the fixed length of 53 bytes, called cells, and the cells are transferred. Intensive studies have been made ...
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In the ATM system, all multimedia information, such as voice, picture and data, is divided into packets with the fixed length of 53 bytes, called cells, and the cells are transferred. Intensive studies have been made on the performance of the system, where such multimedia information is multiplexed in the network switch. In the ATM network, the cell loss is not compensated, and it is necessary that the end-user should recover from the errors in order to realize highly reliable data transfer among computers. As one such approach, the error-correcting cone (FEC) has been considered interesting. From such a viewpoint, this paper evaluates analytically the data transfer performance when FEC is used. When FEC is used, the redundant cell produces an overhead, which may enhance congestion when the traffic in the network is high and deteriorate the performance. Also, from this viewpoint, this paper considers the priority control, where the redundant cells are discarded positively when the network is congested. The effectiveness of the approach is examined, as in the data transfer performance for the case where the video and the data exist together in the traffic, and it is demonstrated that the control parameters in the priority control are especially important in that case.
An open problem proposed by R.S. Safavi-Naini and J.R. Seberry in 1991 is solved by a systematic implementation of subliminal channels of capacities 1-bit, 2-bits and t-bits in general.
An open problem proposed by R.S. Safavi-Naini and J.R. Seberry in 1991 is solved by a systematic implementation of subliminal channels of capacities 1-bit, 2-bits and t-bits in general.
A lightweight mutual authentication protocol is proposed for RFID systems in which both the tags and the reader can be authenticated to each other. The proposed protocol is based on the McEliece cryptosystem without r...
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ISBN:
(纸本)9781457720529
A lightweight mutual authentication protocol is proposed for RFID systems in which both the tags and the reader can be authenticated to each other. The proposed protocol is based on the McEliece cryptosystem without requiring Radio Frequency Identification (RFID) tags to store the large matrices needed in the McEliece cryptosystem. Complex computational operations in the McEliece cryptosystem are removed from the RFID tags, as they only perform simple binary operations on short vectors. The size of the memory needed in the RFID tag is trivial and suitable for low-cost tags. Readers perform most of the encryption and decryption involved in the authentication protocol using McEliece functions. After every authentication, the content of the RFID tag is securely refreshed making it ready for a new round of authentication. This will ensure that the tags cannot be traced by unauthorized readers, thereby protecting the privacy of the RFID tags.
A new principle of the shaping the nonline illumination is given. It is suitable for realization of noncontact high-precision optical measuring systems for determination the surface profile of large scale objects.
A new principle of the shaping the nonline illumination is given. It is suitable for realization of noncontact high-precision optical measuring systems for determination the surface profile of large scale objects.
Our task of quantum list decoding for a classical block code is to recover from a given quantumly corrupted codeword a short list containing all messages whose codewords have high "presence" in this quantuml...
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ISBN:
(纸本)9781920682460
Our task of quantum list decoding for a classical block code is to recover from a given quantumly corrupted codeword a short list containing all messages whose codewords have high "presence" in this quantumly corrupted codeword. All known families of efficiently quantum list decodable codes, nonetheless, have exponentially-small message rate. We show that certain generalized Reed-Solomon codes concatenated with Hadamard codes of polynomially-small rate and constant codeword alphabet size have efficient quantum list decoding algorithms, provided that target codewords should have relatively high presence in a given quantumly corrupted codeword.
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