893 resultados para limited contacts
Resumo:
We numerically demonstrate a new fiber laser architecture supporting spectral compression of negatively chirped pulses in passive normally dispersive fiber. Such a process is beneficial for improving the energy efficiency of the cavity as it prevents narrow spectral filtering from being highly dissipative. The proposed laser design provides an elegant way of generating transform-limited picosecond pulses. © 2012 IEEE.
Resumo:
By spectral analysis, and using joint time-frequency representations, we present the theoretical basis to design invariant band-limited Airy pulses with an arbitrary degree of robustness, and an arbitrary range of single mode fiber chromatic dispersion. The numerically simulated examples confirm the theoretically predicted pulse partial invariance in the propagation of the pulse in the fiber.
Resumo:
We experimentally investigate the channel estimation and compensation in a chromatic dispersion (CD) limited 20Gbit/s optical fast orthogonal frequency division multiplexing (F-OFDM) system with up to 840km transmission. It is shown that symmetric extension based guard interval (GI) is required to enable CD compensation using one-tap equalizers. As few as one optical F-OFDM symbol with four and six pilot tones per symbol can achieve near-optimal channel estimation and compensation performance for 600km and 840km respectively.
Resumo:
Marketing managers increasingly recognize the need to measure and communicate the impact of their actions on shareholder returns. This study focuses on the shareholder value effects of pharmaceutical direct-to-consumer advertising (DTCA) and direct-to-physician (DTP) marketing efforts. Although DTCA has moderate effects on brand sales and market share, companies invest vast amounts of money in it. Relying on Kalman filtering, the authors develop a methodology to assess the effects from DTCA and DTP on three components of shareholder value: stock return, systematic risk, and idiosyncratic risk. Investors value DTCA positively because it leads to higher stock returns and lower systematic risk. Furthermore, DTCA increases idiosyncratic risk, which does not affect investors who maintain well-diversified portfolios. In contrast, DTP marketing has modest positive effects on stock returns and idiosyncratic risk. The outcomes indicate that evaluations of marketing expenditures should include a consideration of the effects of marketing on multiple stakeholders, not just the sales effects on consumers.
Resumo:
We numerically demonstrate a new fiber laser architecture supporting spectral compression of negatively chirped pulses in passive normally dispersive fiber. Such a process is beneficial for improving the energy efficiency of the cavity as it prevents narrow spectral filtering from being highly dissipative. The proposed laser design provides an elegant way of generating transform-limited picosecond pulses. © 2012 IEEE.
Resumo:
We tested the hypothesis that the differences in performance between developmental dyslexics and controls on visual tasks are specific for the detection of dynamic stimuli. We found that dyslexics were less sensitive than controls to coherent motion in dynamic random dot displays. However, their sensitivity to control measures of static visual form coherence was not significantly different from that of controls. This dissociation of dyslexics' performance on measures that are suggested to tap the sensitivity of different extrastriate visual areas provides evidence for an impairment specific to the detection of dynamic properties of global stimuli, perhaps resulting from selective deficits in dorsal stream functions. © 2001 Lippincott Williams & Wilkins.
Resumo:
The main aim of this study is to undertake a critical examination of the ethical and developmental performance of an Islamic bank as communicated in its annual reports over a period of 28 years (1983-2010). Islami Bank Bangladesh Limited's (IBBL hereafter) ethical performance and disclosures are further analyzed through interviews conducted with the bank's senior management. The key findings include an overall increase in ethical disclosures during the study period. However, the focus on various stakeholders' needs has varied over time reflecting the evolving nature of the Islamic finance industry over the last three decades. Based on a secular economy, IBBL focused in the first two decades on the "Particular" Shariah compliance disclosure as a way of establishing its reputation and differentiating itself from conventional banks in a dual banking system. Post 2005, the ethical performance and disclosure shifted to more "Universal" disclosures such as sustainability, charity, employees, and community related disclosures signaling responsible conduct and the bank's adoption of a "wider stakeholder approach." However the bank is still failing to provide full disclosure on certain significant categories such as sources and uses of disposable income, thereby contradicting the principles of full and comprehensive disclosure and accountability. In addition, the structure of IBBL's investment portfolio reveals an overreliance on debt-based financial instruments and a shortcoming in fulfilling the developmental and social objectives of Islamic finance. This is evidenced by the "qualified" Shariah Supervisory Board reports that the bank consistently received. This research provides further evidence that Islamic banking and Finance in its current practices reflect the "global" and the "local" influences in an era dominated by global conventional finance. © 2014 Springer Science+Business Media Dordrecht.
Resumo:
We experimentally investigate the channel estimation and compensation in a chromatic dispersion (CD) limited 20Gbit/s optical fast orthogonal frequency division multiplexing (F-OFDM) system with up to 840km transmission. It is shown that symmetric extension based guard interval (GI) is required to enable CD compensation using one-tap equalizers. As few as one optical F-OFDM symbol with four and six pilot tones per symbol can achieve near-optimal channel estimation and compensation performance for 600km and 840km respectively.
Resumo:
We have generated near-transform-limited picosecond pulses(ΔτΔν≈0.45) from a gain-switched diode laser using periodic and chirped fiber Bragg gratings. This configuration reduced the spectral bandwidth from 11 to 0.08 nm and the pulse duration was reduced, from 30 to<18 ps. Average and peak powers of 27 and 770 mW, respectively, were obtained.
Resumo:
We introduce a general technique how to reveal in experiments of limited electrical bandwidth which is lower than the optical bandwidth of the optical signal under study, whether the statistical properties of the light source obey Gaussian distribution or mode correlations do exist. To do that one needs to perform measurements by decreasing the measurement bandwidth. We develop a simple model of bandwidth-limited measurements and predict universal laws how intensity probability density function and intensity auto-correlation function of ideal completely stochastic source of Gaussian statistics depend on limited measurement bandwidth and measurement noise level. Results of experimental investigation are in good agreement with model predictions. In particular, we reveal partial mode correlations in the radiation of quasi-CW Raman fibre laser.
Resumo:
This paper presents a practical approach for digitizing city landmarks based on free and limited Web resources. The digital replicas are then placed on the Web using popular services, like Google earth, and are accessible to a huge user base. The method is easily applicable and quite valuable to organizations with limited funding.
Resumo:
The volume The Dialectics of Modernity - Recognizing Globalization. Studies on the Theoretical Perspectives of Globalization is the product of a work of that quarter of the century, which has been continuing, since 1989 up today, the true beginning of the globalization. Therefore, because that concept was not existing at that time, the work is not yet directed, in the first years, on the globalization itself. As it can be seen, this concept pushed through only in the second half of the nineties, when the concept could also be already statistically revealed in the world press. How a group of researchers from Hungary was enquirying during the nineties, according to partners of conversation at home and abroad, with whom one could talk about how the new world emerging with 1989 can actually be described, is a long story, the theory of which consists in the fact, that we apparently live in a world, where the most part of the people, even worse, even most of the intellectuals are hardly interested in how this one really looks like. On looking for partners, the circle of the authors of this volume was created. In Hungary, we quickly reached our limit (which much later did not prevent us from appearing, such as if we had always been living in the theoretically worked globalization). The French group around Jacques Poulain reacted the fastest way (and later around Francois de Bernard, with his particularly valuable homepage www.mondialisations.org), not much later the contact with the Russian colleagues around Alexandr Shumakov was created, in which Encyclopedia of the Globalization our contribution could already appear in 2003. On these traces, we came to the productive relationship with Leonid Grinin and Andrey Korotayev. Finally, we mention the Fürstenfeld's initiative, founded since 2009 with Melitta Becker's help in the framework of the Centre for the Interdisciplinary Research in this Austrian city. A relevant part of the author inside this book participated from the beginning in the work of the group. The individual contributions to this volume are linked together by a common interest in knowledge. This is the theoretical view of the phenomenon of the globalization. From the beginning, it was not further defined or limited to certain approaches, particularly an independent theory of the globalization was not intended. We started from the fact, that every legitimately revealed theoretical approach can contribute legitimately to a later theory of the globalization. In this way, the further contacts with Nico Stehr and the members of the Dresden group for the investigation of the security problems arose, mainly with Ernst Woit. Hegel defined the philosophy as the flight of the Owl of Minerva, which "begins its flight only with the falling twilight". Through the theoretical investigation of the globalization always becoming interdisciplinary, we wanted by no means to debate about this incomparable aphorism. We simply started from the conviction, that a new reality should not remain without any description.