Experimental demonstration of impairment

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experimental demonstration of impairment

Use of this web site signifies your agreement to the terms and conditions. Personal Sign In. For IEEE to continue sending you helpful information on our products and services, please consent to our updated Privacy Policy. Email Address. Sign In. Fog is known as one of the most detrimental atmospheric conditions that causes outdoor optical wireless communications to be unreliable.

Recognizing the least attenuation coefficient and a taillight color of a vehicle, a red light-emitting diode LED was employed in the experiment. In addition, a Fresnel lens and multiple photodiodes are utilized to efficiently counteract the impairment caused by fog. The experimental results demonstrate that the proposed VLC-based V2V system offers a reliable V2V data transmission over the fog-impaired optical channel with a relatively high signal-to-noise ratio SNReven under a heavy-fog condition.

Article : Date of Publication: 10 November DOI: Need Help?This website uses cookies to deliver some of our products and services as well as for analytics and to provide you a more personalized experience. Click here to learn more. By continuing to use this site, you agree to our use of cookies. We've also updated our Privacy Notice. Click here to see what's new. Core optical networks using reconfigurable optical switches and tunable lasers appear to be on the road towards widespread deployment and could evolve to all-optical mesh networks in the coming future.

The key building blocks of the NPOT, consisting of network description repositories, the physical layer performance evaluator, the impairment aware routing and wavelength assignment engines, the component placement modules, failure handling, and the integration of NPOT in the control plane are the main contributions of this study. Besides, the experimental result of DICONET proposal for centralized and distributed control plane integration schemes and the performance of the failure handling in terms of restoration time is presented in this study.

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Journal of Lightwave Technology Vol. Lightwave Technol. Not Accessible Your account may give you access. Abstract Core optical networks using reconfigurable optical switches and tunable lasers appear to be on the road towards widespread deployment and could evolve to all-optical mesh networks in the coming future.

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Experimental demonstration of chaotic instability in biological nitrification

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Understanding the basis of unpredictability in nitrification is critical because the loss or impairment of this function might influence the balance of nitrogen in the environment and also has biotechnological implications. One explanation for unpredictability is the presence of chaotic behavior; however, proving such behavior from experimental data is not trivial, especially in a complex microbial community.

Here, we show that chaotic behavior is central to stability in nitrification because of a fragile mutualistic relationship between ammonia-oxidizing bacteria AOB and nitrite-oxidizing bacteria NOBthe two major guilds in nitrification.

Three parallel chemostats containing mixed microbial communities were fed complex media for days, and nitrification performance, and abundances of AOB, NOB, total bacteria and protozoa were quantified over time.

Lyapunov exponent calculations, supported by surrogate data and other tests, showed that all guilds were sensitive to initial conditions, suggesting broad chaotic behavior. However, NOB were most unstable among guilds and displayed a different general pattern of instability.

We conclude that nitrification is prone to chaotic behavior because of a fragile AOB—NOB mutualism, which must be considered in all systems that depend on this critical reaction. All microbial ecosystems are comprised of diverse groups of organisms that fulfill similar ecological interactions as macroscopic systems. Predation, competition and mutualism are all enacted and can result in complex behavior, including chaos May, ; Huisman and Weissing, For example, recent experimental data showed that a protozoan predator conditionally displayed chaotic behavior in a two prey-one predator axenic culture Becks et al.

Although this result is interesting, real microbial communities are neither this simple nor can be studied with such limited data Juretschko et al.

Determining the possibility of chaotic behavior in microbial guilds that perform key functions, such as biological nitrification, is critical to understanding sustainability of such processes that have both environmental for example, the biogeochemical nitrogen cycle N-cycle and biotechnological for example, waste treatment processes significance.

The goal of this work was to experimentally assess the basis of stability in nitrification, including the possibility of chaotic behavior. Finally, nitrifying-bacteria are slow growers, nutritionally inflexible, sensitive to inhibitors and less phylogenetically diverse than many other key functional guilds Balmelle et al. As such, destabilization can result in unrecoverable loss of function, which can have major effects on natural and engineered systems reliant on the reaction Vitousek et al.

The possibility of chaotic behavior in nitrifying systems was suggested over 20 years ago Dean, ; however, no experimental proof exists. This has been largely due to inadequate detection methods for monitoring specific microbial guilds in real systems, and the general difficulty of gaining enough and appropriate experimental data to satisfy the needs of rigorous mathematical analysis Turchin, With the advent of new molecular biological tools Daims et al.

LEs can be calculated from experimental results, but such exponents only describe trends in stability and it is tenuous to extend local LEs to the entire system. However, experimental LEs, when supported by the mathematical validation of determinism and nonlinearity in the time series, can provide valuable insights into the basis of stability in a process like nitrification.

In this study, three aerobic chemostats were fed complex liquid media at different dilution rates; AOB, NOB and total bacteria, and protozoan guilds were monitored over time using real-time PCR and direct enumeration, respectively.

experimental demonstration of impairment

Chemostats were employed because community stability is influenced by dilution rate Dean, ; Funasaki and Kot, ; Vayenas and Pavlou, ; Kooi and Boer,and complex non-selective growth media were used because we wanted to examine nitrification within a realistic mixed microbial community.

This approach made guild quantification and mathematical analysis more difficult, but it also permits the study of guild dynamics in a quasi-natural setting. Finally, chemostat dilution rates were chosen to differentially stress nitrifying guilds in different reactors, and nitrification efficiency was quantified to assess microbial function relative to guild stability. The reactors were then fed simulated wastewater only in parallel for over days, initially operated as batch and fill-and-draw units to increase biosolids levels, and then as chemostats with dilution rates of 0.

Although no replicate reactors were employed in the experimental design largely due to cost and operational practicalitythe three reactors were monitored in fine detail with a high-level quality control, which ensured as much stationarity as possible in the non-replicate reactors.

The feed carboy was fitted with a drawtube that passed through a port in the refrigerator wall to pumps that fed the same media in parallel to each reactor at carefully regulated rates.

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The actual volume of media removed differed among reactors, but carboy feed volumes and reactor effluent volumes were logged daily to verify proper operation of the pumps and validate flow rates. Lines were replaced weekly with clean and presterilized lines. Biostat i Twin Controllers continuously monitored dissolved oxygen DO and pH, and regulated reactor operations. Compressed air was provided to the reactors through sterile filters Gelman 0. The reactors were sampled very systematically to quantify guild abundances and reactor performance over time.In transparent optical networks, the signal experiences the impact of various phenomena that degrade its quality.

Considering the impact of physical layer impairments PLIs on transparent [1] and highly dynamic optical networks [2] has received much attention recently. The work in [1] reported the result of a centralized integration scheme for transparent networks considering various PLIs, while [4] only investigated a distributed GMPLS integration for translucent networks.

This paper demonstrates the performance of centralized and distributed impairment-aware control plane approaches over a realistic node experimental test-bed under dynamic traffic conditions. Initial simulation results were reported in [5] and experimental results are reported here. To the best of our knowledge, for the first time, impairment-aware control plane schemes with integrated real-time Quality of Transmission QoT estimator are demonstrated. Location of Repository.

OAI identifier: oai:upcommons. Provided by: UPCommons. Suggested articles.This website uses cookies to deliver some of our products and services as well as for analytics and to provide you a more personalized experience. Click here to learn more.

By continuing to use this site, you agree to our use of cookies. We've also updated our Privacy Notice. Click here to see what's new. The impact of physical layer impairments in optical network design and operation has received significant attention in the last years, thereby requiring estimation techniques to predict the quality of transmission QoT of optical connections before being established.

In this paper, we report on the experimental demonstration of a case-based reasoning CBR technique to predict whether optical channels fulfill QoT requirements, thus supporting impairment-aware networking.

Ben Yoo J. Lorenzo, and Idelfonso Tafur Monroy J. Pinart, N. Sambo, E. Le Rouzic, F. Cugini, and P. Castoldi J.

experimental demonstration of impairment

Azodolmolky, J. Angelou, F.

experimental demonstration of impairment

Agraz, L. Velasco, S. Spadaro, Y. Pointurier, A. Francescon, C.

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Saradhi, P. Kokkinos, E. Varvarigos, S.China E-mail: jwang8 njau. Lactoferrin LF plays critical roles in various physiological processes. However, its protective effects on small intestinal epithelial cells remain poorly understood.

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This study aimed to investigate its protective effects and underlying mechanisms in vitro on lipopolysaccharide LPS -challenged intestinal porcine epithelial cells IPEC-J2 cells. Moreover, the LF treatment decreased cell permeability, enhanced the expression of claudin-1 protein, and inhibited the expression of the myosin light-chain kinase MLCK protein in LPS-challenged cells. If you are not the author of this article and you wish to reproduce material from it in a third party non-RSC publication you must formally request permission using Copyright Clearance Center.

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Search Advanced. Current Journals. Archive Journals. All Journals. New Titles. Pick and Choose. Literature Updates.Fiber nonlinearity is one of the major limitations to the achievable capacity in long distance fiber optic transmission systems. Nonlinear impairments are determined by the signal pattern and the transmission system parameters.

Deterministic algorithms based on approximating the nonlinear Schrodinger equation through digital back propagation, or a single step approach based on perturbation methods have been demonstrated, however, their implementation demands excessive signal processing resources, and accurate knowledge of the transmission system.

Journal of Lightwave Technology

A completely different approach uses machine learning algorithms to learn from the received data itself to figure out the nonlinear impairment.

Without prior knowledge of the transmission system, the neural network tensor weights are constructed from training data thanks to the intra-channel cross-phase modulation and intra-channel four-wave mixing triplets used as input features. Abstract Fiber nonlinearity is one of the major limitations to the achievable capacity in long distance fiber optic transmission systems.


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