872 resultados para Creole dialects, Danish


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We experimentally demonstrate performance enhancements enabled by weighted digital back propagation method for 28 Gbaud PM-16QAM transmission systems, over a 250 km ultra-large area fibre, using only one back-propagation step for the entire link, enabling up to 3 dB improvement in power tolerance with respect to linear compensation only. We observe that this is roughly the same improvement that can be obtained with the conventional, computationally heavy, non-weighted digital back propagation compensation with one step per span. As a further benchmark, we analyze performance improvement as a function of number of steps, and show that the performance improvement saturates at approximately 20 steps per span, at which a 5 dB improvement in power tolerance is obtained with respect to linear compensation only. Furthermore, we show that coarse-step self-phase modulation compensation is inefficient in wavelength division multiplexed transmission.

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We report for the first time, the impact of cross phase modulation in WDM optical transport networks employing dynamic 28 Gbaud PM-mQAM transponders (m = 4, 16, 64, 256). We demonstrate that if the order of QAM is adjusted to maximize the capacity of a given route, there may be a significant degradation in the transmission performance of existing traffic for a given dynamic network architecture. We further report that such degradations are correlated to the accumulated peak-to-average power ratio of the added traffic along a given path, and that managing this ratio through pre-distortion reduces the impact of adjusting the constellation size of neighboring channels. (C) 2011 Optical Society of America

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We experimentally demonstrate a novel synchronous 10.66Gbit/s DPSK OEO regenerator which uses a feed-forward carrier extraction scheme with an injection-locked laser to synchronize the regenerated signal wavelength to the incoming signal wavelength. After injection-locking, a low-cost DFB laser used at the regenerator exhibited the same linewidth characteristics as the narrow line-width transmitter laser. The phase regeneration properties of the regenerator were evaluated by emulating random Gaussian phase noise applied to the DPSK signal before the regenerator using a phase modulator driven by an arbitrary waveform generator. The overall performance was evaluated in terms of electrical eye-diagrams, BER measurements, and constellation diagrams.

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Limitations in the performance of coherent transmission systems employing digital back-propagation due to four-wave mixing impairments are reported for the first time. A significant performance constraint is identified, originating from four-wave mixing between signals and amplified spontaneous emission noise which induces a linear increase in the standard deviation of the received field with signal power, and linear dependence on transmission distance.

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We report the performance of coherently-detected nine-channel WDM transmission over high dispersion fibers, using polarization multiplexed m-ary quadrature amplitude modulation (m = 4, 16, 64, 256) at 112 Gbit/s. Compensation of fiber nonlinearities via digital back-propagation enables up to 10 dB improvement in maximum transmittable power and similar to 8 dB Q(eff) improvement which translates to a nine-fold enhancement in transmission reach for PM-256QAM, where the largest improvements are associated with higher-order modulation formats. We further demonstrate that even under strong nonlinear distortion the transmission reach only reduces by a factor of similar to 2.5 for a 2 unit increase in capacity (log(2)m) when full band DBP is employed, in proportion to the required back-to-back OSNR.

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We report for the first time on the limitations in the operational power range of network traffic in the presence of heterogeneous 28-Gbaud polarization-multiplexed quadrature amplitude modulation (PM-mQAM) channels in a nine-channel dynamic optical mesh network. In particular, we demonstrate that transponders which autonomously select a modulation order and launch power to optimize their own performance will have a severe impact on copropagating network traffic. Our results also suggest that altruistic transponder operation may offer even lower penalties than fixed launch power operation.

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In this letter, we directly compare digital back-propagation (DBP) with spectral inversion (SI) both with and without symmetry correction via dispersive chirping, and numerically demonstrate that predispersed SI outperforms traditional SI, and approaches the performance of computationally exhaustive ideal DBP. Furthermore, we propose for the first time a novel practical scheme employing predispersed SI to compensate the bulk of channel nonlinearities, and DBP to accommodate the residual penalties due to varying SI location, with predispersed SI ubiquitously employed along the transmission link with <;0.5-dB penalty. Our results also show that predispersed SI enables partial compensation of cross-phase modulation effects, increasing the transmission reach by ×2.

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We investigate electronic mitigation of linear and non-linear fibre impairments and compare various digital signal processing techniques, including electronic dispersion compensation (EDC), single-channel back-propagation (SC-BP) and back-propagation with multiple channel processing (MC-BP) in a nine-channel 112 Gb/s PM-mQAM (m=4,16) WDM system, for reaches up to 6,320 km. We show that, for a sufficiently high local dispersion, SC-BP is sufficient to provide a significant performance enhancement when compared to EDC, and is adequate to achieve BER below FEC threshold. For these conditions we report that a sampling rate of two samples per symbol is sufficient for practical SC-BP, without significant penalties.

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We report that, contrary to common perception, intra-channel nonlinearity compensation offers significant improvements of up to 4dB, in nonlinear tolerance (Q-factor), in a flexible traffic scenario, and further improvements with increasing local link dispersion, for an optical transport network employing flexible 28Gbaud PM-mQAM transponders.

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We review recent advances in all-optical OFDM technologies and discuss the performance of a field trial of a 2 Tbit/s Coherent WDM over 124 km with distributed Raman amplification. The results indicate that careful optimisation of the Raman pumps is essential. We also consider how all-optical OFDM systems perform favourably against energy consumption when compared with alternative coherent detection schemes. We argue that, in an energy constrained high-capacity transmission system, direct detected all-optical OFDM with `ideal' Raman amplification is an attractive candidate for metro area datacentre interconnects with ~100 km fibre spans, with an overall energy requirement at least three times lower than coherent detection techniques.

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In the light of the financial crisis and the radically changed conditions in the market place, international leadership development is facing new demands. The Danish-based International Leadership Institute Mannaz has researched the new conditions in collaboration with the Institute of Executive Development in the United States. The research, conducted in 2008 and 2009, combines, in an innovative way, quantitative and qualitative inputs, from both current and future perspectives, from some 111 senior Corporate Executives, Heads of Human Resources and of Learning and Organisational Development in large international corporations headquartered in Europe and the United States; together with the thoughts of some 50 experienced practitioners involved in executive coaching as well as in designing, developing and facilitating leadership development programmes. Also we include a section summarising the key findings from recently published research from other leadership development surveys. Conclusions reveal that the crisis has propelled a long-awaited decline of the traditional classroom-based educational approach to leadership development. Instead, effective leadership development is suggested to build on experiential learning approaches rooted in real life, real time and allowing for more immediate impact and providing for considerably higher relevance and motivation. Coaching, leaders teaching leaders, stretch assignments, action learning, peer networking, customer insights and selective use of technology are seen as important contributors to the leadership development process going forward.

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We report for the first time on the limitations in the operational power range of few-mode fiber based transmission systems, employing 28Gbaud quadrature phase shift keying transponders, over 1,600km. It is demonstrated that if an additional mode is used on a preexisting few-mode transmission link, and allowed to optimize its performance, it will have a significant impact on the pre-existing mode. In particular, we show that for low mode coupling strengths (weak coupling regime), the newly added variable power mode does not considerably impact the fixed power existing mode, with performance penalties less than 2dB (in Q-factor). On the other hand, as mode coupling strength is increased (strong coupling regime), the individual launch power optimization significantly degrades the system performance, with penalties up to ∼6dB. Our results further suggest that mutual power optimization, of both fixed power and variable power modes, reduces power allocation related penalties to less than 3dB, for any given coupling strength, for both high and low differential mode delays. © 2013 Optical Society of America.

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This volume focuses on the closely allied yet differing linguistic varieties of Birmingham and its immediate neighbour to the west, the industrial heartland of the Black Country. Both of these areas rose to economic prominence and success during the Industrial Revolution, and both have suffered economically and socially as a result of post-war industrial decline. The industrial heritage of both areas has meant that tight knit and socially homogeneous individual areas in each region have demonstrated in many respects little linguistic change over time, and have continued to exhibit linguistic features, especially morphological constructions, peculiar to these areas or now restricted to these areas. At the same time, immigration from other areas of the British Isles over time, from Commonwealth countries and later from EU member states, together with increased social mobility, have meant that newly developing structures and more widespread UK linguistic phenomena have spread into these varieties. This volume provides a clear description of the structure of the linguistic varieties spoken in the two areas. Following the structure of the Dialects of English volumes, it provides: •A comprehensive overview of the phonological, grammatical and lexical structure of both varieties, as well as similarities between the two varieties and distinguishing features •Thorough discussion of the historical and social factors behind the development of the varieties and the stigma attached to these varieties •Discussion of the unusual situation of the Black Country as an area undefined in geographical and administrative terms, existing only in the imagination •Examples of the variety from native speakers of differing ethnicities, ages and genders •An annotated bibliography for further consultation

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This study for the first time demonstrates and analyses the full extent of Danish impressionist writer Herman Bang’s influence on one of Germany’s major authors, Thomas Mann. Mann was an avid reader of Bang’s works and he regarded the Scandinavian writer as a kindred spirit, a “brother up north”, who “taught [him] much”. It has previously been accepted that Bang was an inspiration for Mann in his formative years. However, as this study conclusively shows, references to Bang’s works occur throughout Mann’s writings, from the early novellas to the late novels. The book argues that Mann was not only impressed by Bang’s highly individual style of impressionist writing but that his fascination for Bang’s works was to a large extent based on this author’s recurrent depiction of decadence, his handling of artistic motifs and his treatment of erotic themes. Bang’s topical focus on the problematically isolated lives of artists and aristocrats as well as his insights on the destructive nature of love and sexuality – particularly of homoerotic desire – were surprisingly similar to Mann’s own views on these topics and yet provoked him to produce heavily referenced counter versions of Bang’s works. This phenomenon is explored in the context of Mann’s struggle with his own homosexuality and the attraction that death and decadence exerted over him. Most of Mann’s writings are in that way indebted to Bang. In addition, Mann’s frequent use of homoerotic subtexts and his depiction of female characters were noticeably influenced by Bang’s literary techniques. All these different, yet closely interlinked, aspects of Mann’s creative appropriation of Bang’s works are analysed and discussed in this study. To conclude, Mann’s references to Bang’s works are schematised and an attempt is made to characterise Mann’s intertextual practice in general in the context of his famous use of irony.

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The world is connected by a core network of long-haul optical communication systems that link countries and continents, enabling long-distance phone calls, data-center communications, and the Internet. The demands on information rates have been constantly driven up by applications such as online gaming, high-definition video, and cloud computing. All over the world, end-user connection speeds are being increased by replacing conventional digital subscriber line (DSL) and asymmetric DSL (ADSL) with fiber to the home. Clearly, the capacity of the core network must also increase proportionally. © 1991-2012 IEEE.