Interleavers and BCH codes for coherent DQPSK systems with laser phase noise

The relatively high phase noise of coherent optical systems poses unique challenges for forward error correction (FEC). In this letter, we propose a novel semianalytical method for selecting combinations of interleaver lengths and binary Bose-Chaudhuri-Hocquenghem (BCH) codes that meet a target post-FEC bit error rate (BER). Our method requires only short pre-FEC simulations, based on which we design interleavers and codes analytically. It is applicable to pre-FEC BER ∼10-3, and any post-FEC BER. In addition, we show that there is a tradeoff between code overhead and interleaver delay. Finally, for a target of 10-5, numerical simulations show that interleaver-code combinations selected using our method have post-FEC BER around 2× target. The target BER is achieved with 0.1 dB extra signal-to-noise ratio.

Dimensioning BCH codes for coherent DQPSK systems with laser phase noise and cycle slips

Forward error correction (FEC) plays a vital role in coherent optical systems employing multi-level modulation. However, much of coding theory assumes that additive white Gaussian noise (AWGN) is dominant, whereas coherent optical systems have significant phase noise (PN) in addition to AWGN. This changes the error statistics and impacts FEC performance. In this paper, we propose a novel semianalytical method for dimensioning binary Bose-Chaudhuri-Hocquenghem (BCH) codes for systems with PN. Our method involves extracting statistics from pre-FEC bit error rate (BER) simulations. We use these statistics to parameterize a bivariate binomial model that describes the distribution of bit errors. In this way, we relate pre-FEC statistics to post-FEC BER and BCH codes. Our method is applicable to pre-FEC BER around 10-3 and any post-FEC BER. Using numerical simulations, we evaluate the accuracy of our approach for a target post-FEC BER of 10-5. Codes dimensioned with our bivariate binomial model meet the target within 0.2-dB signal-to-noise ratio.

Novel BCH code design for mitigation of phase noise induced cycle slips in DQPSK systems

We show that by proper code design, phase noise induced cycle slips causing an error floor can be mitigated for 28 Gbaud DQPSK systems. Performance of BCH codes are investigated in terms of required overhead. © 2014 OSA.

Tér és teljesség - Fenntarthatóság a területhasználatban és az építési tevékenységben

A cikk a fenntarthatóság témakörét a területhasználatra és az építési tevékenységre fókuszálva járja körül. Noha kész receptekkel nem szolgál, természet, társadalom és gazdaság egészlátó (integrált) szemlélete alapján néhány radikális, normalitást célzó – főként ökológiai gazdaságtani – szempontot fogalmaz meg, amelyekkel egy fenntarthatóbb rendszert alakíthatunk ki. Mivel az írást a fenntarthatóság kérdésköre ihlette, a természeti környezettel kapcsolatos megfontolások a kidolgozottabbak, s csak esetlegesen (ám elválaszthatatlanul) kapcsolódnak hozzájuk a társadalmi vonatkozások. A tanulmányból mindenesetre – implicit módon – így is kitűnik, hogy a fenntarthatóság eszméje (amely elsősorban a természeti korlátokból fakad) nem mond ellent a társadalmi-emberi kiteljesedésnek, azaz a közjónak, ha az embert és a társadalmat a maga teljességében szemléljük, s nem valamilyen torz és leegyszerűsítő (például a homo oeconomicus) ideológia alapján. A cikkben a radikális javaslatokat kevésbé radikális – környezetgazdasági – nézetek ellenpontozzák, mintegy érzékeltetve a problémakör és a megközelítésmódok rendkívüli összetettségét.

Humán tér-kép. A humán és fejlesztéspolitikai tényezők földrajza Magyarországon

I. fejezet Bevezetés: a kreativitás földrajzi eloszlása II. fejezet A kreativitás térszerkezeti változása Magyarországon az ezredforduló után III. fejezet Fejlesztéspolitika térben és időben: az Európai Unió fejlesztési célú támogatásai Magyarországon – 2004-2015 IV. fejezet Magyarország deviancia-térképe területi előrejelzésekkel

Mesure du potentiel évoqué visuel (PEV) et du temps de réaction (TR) en corrélation avec les différentes ségrégations de textures : à savoir les stimuli de premiers et de seconds ordres

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Low-complexity BCH codes with optimized interleavers for DQPSK systems with laser phase noise

The presence of high phase noise in addition to additive white Gaussian noise in coherent optical systems affects the performance of forward error correction (FEC) schemes. In this paper, we propose a simple scheme for such systems, using block interleavers and binary Bose–Chaudhuri–Hocquenghem (BCH) codes. The block interleavers are specifically optimized for differential quadrature phase shift keying modulation. We propose a method for selecting BCH codes that, together with the interleavers, achieve a target post-FEC bit error rate (BER). This combination of interleavers and BCH codes has very low implementation complexity. In addition, our approach is straightforward, requiring only short pre-FEC simulations to parameterize a model, based on which we select codes analytically. We aim to correct a pre-FEC BER of around (Formula presented.). We evaluate the accuracy of our approach using numerical simulations. For a target post-FEC BER of (Formula presented.), codes selected using our method result in BERs around 3(Formula presented.) target and achieve the target with around 0.2 dB extra signal-to-noise ratio.

Mesure du potentiel évoqué visuel (PEV) et du temps de réaction (TR) en corrélation avec les différentes ségrégations de textures : à savoir les stimuli de premiers et de seconds ordres.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Algunas posibles incidencias de Ov. Tr. 4, 10 en los prólogos y epílogos de los Libros III y IV de las Fábulas de Fedro

Fedro realiza a lo largo de su obra un esfuerzo consciente y prolongado por obtener un lugar, que cree merecido, como recreador latino del género fabulístico. A partir del epílogo del L. II de sus Fábulas, el poeta da cuenta de un cambio en su posición como escritor y un incremento de la recepción de su obra en los círculos letrados. En el prólogo del L. IV declara que su esfuerzo se ha visto recompensado, porque ya sus obras eran copiadas y leídas. Por su parte Ovidio en Tr. 4, 10 declara que, gracias a la Musa, tiene un lugar destacado en el Helicón e, inmune a la Envidia, ha conseguido en vida un renombre por su obra. En esta ponencia, mediante la identificación de recurrencias léxicas y analogías estructurales, se explora la posible incidencia de Ov. Tr. 4, 10 en algunos prólogos y epílogos fedrianos, tomando como centro los del L. III, donde se encuentran condensadas las reflexiones del poeta acerca de supropia escritura, de su imagen como escritor y la preocupación por los ataques de la Envidia, representada por sus críticos y detractores.

Laboratory performance evaluation of CIR-emulsion and its comparison against CIR-foam test results from Phase III, TR-578

Currently, no standard mix design procedure is available for CIR-emulsion in Iowa. The CIR-foam mix design process developed during the previous phase is applied for CIR-emulsion mixtures with varying emulsified asphalt contents. Dynamic modulus test, dynamic creep test, static creep test and raveling test were conducted to evaluate the short- and long-term performance of CIR-emulsion mixtures at various testing temperatures and loading conditions. A potential benefit of this research is a better understanding of CIR-emulsion material properties in comparison with those of CIR-foam material that would allow for the selection of the most appropriate CIR technology and the type and amount of the optimum stabilization material. Dynamic modulus, flow number and flow time of CIR-emulsion mixtures using CSS-1h were generally higher than those of HFMS-2p. Flow number and flow time of CIR-emulsion using RAP materials from Story County was higher than those from Clayton County. Flow number and flow time of CIR-emulsion with 0.5% emulsified asphalt was higher than CIR-emulsion with 1.0% or 1.5%. Raveling loss of CIR-emulsion with 1.5% emulsified was significantly less than those with 0.5% and 1.0%. Test results in terms of dynamic modulus, flow number, flow time and raveling loss of CIR-foam mixtures are generally better than those of CIR-emulsion mixtures. Given the limited RAP sources used for this study, it is recommended that the CIR-emulsion mix design procedure should be validated against several RAP sources and emulsion types.

Evaluation and Testing of a Lightweight Fine Aggregate Concrete Bridge Deck in Buchanan County, Iowa, TR-648, 2016

Internal curing is a relatively new technique being used to promote hydration of Portland cement concretes. The fundamental concept is to provide reservoirs of water within the matrix such that the water does not increase the initial water/cementitious materials ratio to the mixture, but is available to help continue hydration once the system starts to dry out. The reservoirs used in the US are typically in the form of lightweight fine aggregate (LWFA) that is saturated prior to batching. Considerable work has been conducted both in the laboratory and in the field to confirm that this approach is fundamentally sound and yet practical for construction purposes. A number of bridge decks have been successfully constructed around the US, including one in Iowa in 2013. It is reported that inclusion of about 20% to 30% LWFA will not only improve strength development and potential durability, but, more importantly, will significantly reduce shrinking, thus reducing cracking risk. The aim of this work was to investigate the feasibility of such an approach in a bridge deck.