The use of optical technologies in modern network scenarios has increased in the last decade, mostly due to their support in crucial networking topics (ie, bandwidth and scalability). In parallel, these scenarios have also experienced the emergence of a new paradigm recognized as software‐defined networking (SDN), which bases on the decoupling of forwarding and control functions, with aims to provide a more efficient way to manage network resources compared to legacy networking architectures. As both SDN and optical technologies are constantly being introduced in different networking scenarios (eg, data centers, metro, and access networks), their coexistence becomes a must. In this matter, it is important to notice that SDN was initially designed for electronic‐based networks; hence, its support for optical technologies is still at an early stage. Consequently, integration of both solutions still requires research efforts by the community. In this paper, we present a mechanism to address topology discovery in wavelength‐switching optical transport networks (OTNs). In particular, we discuss the importance of the topology discovery function and analyse the proposed mechanism, which bases itself on the use of wavelength‐specific signaling tones as link‐binding data to provide preservice parallel link discovery in OTNs. Furthermore, we validate the method experimentally against an emulated OTN testbed with two different setups and compare the results to our previous work on this subject, achieving substantial reductions in the total topology discovery time. 相似文献
Placebo white tablet cores (lactose anhydrous [47.6%], corn starch [23.8%], microcrystalline cellulose [19.1%], polyvinylpyrrolidone [7.9%], magnesium stearate [0.8%], and talcum powder [0.8%]) were coated with a colorant (hydroxypropyl methylcellulose [8% w/v], titanium dioxide [0.2% w/v], FD&C yellow No. 6 with aluminum lacquer [0.8% w/v], polyethylene glycol 4000 [0.4% w/v], and purified water [q.s.p. 100 mL]) using a random spraying method during 130 minutes. During the coating process, batches of 21 samples were extracted every 10 minutes and measured with a DigiEye imaging system. The initial cores showed very similar and uniform colors (Mean Color Difference from the Mean [MCDM] of 0.8 CIELAB units), but partially coated tablets showed lower uniformity (MCDM below 2.0 CIELAB units). There was a high color variability (MCDM about 4.0 CIELAB units) among tablets of the same batch in the period between 10 and 30 minutes, which decreased as the coating process progressed, until achieving a final acceptable value (MCDM below 2.0 CIELAB units). During the coating process, L* decreased, C*ab strongly increased, and hab remained nearly constant (disregarding results at 0 and 10 minutes). CIELAB and CIEDE2000 color differences (mainly chroma differences) with respect to the initial color of the tablets were modeled as a function of time by exponential functions with three coefficients. The color change in the interval from 90 to 130 minutes (4.3 CIELAB units, or 2.6 CIEDE2000 units), may be considered negligible bearing in mind the color variability in the batches of 21 samples and typical values of visual color thresholds. 相似文献
One of the most common techniques to find the adequate weights in ordered weighted averaging (OWA) operators is based on the orness concept, where the weights are determined by maximizing the entropy (variation) for a fixed orness value. But such an entropy represents a dispersion measure for nominal variables, while weights in an OWA operator are essentially ordinal rather than nominal. Hence, in this paper, we propose a novel way to determine OWA weights based upon ordinal dispersion measures instead of an standard entropy measure. From this approach, we find an explicit formula for the weights, and we illustrate differences by means some multicriteria decision-making examples. 相似文献
Inspired by the Zadeh approach to fuzzy connectives in fuzzy set theory and by some applications, we introduce and study set-based extended functions, and in particular, set-based extended aggregation functions. These functions reflect neither reordering nor repetition of input values, and, linking different arities, they introduce serious constraints for extended functions. A complete characterization of set-based extended (aggregation) functions is given, and some constructions of such functions are also proposed, including several examples. 相似文献
Air-coupled ultrasonic inspection has been demonstrated to be a non-contact method of great interest in non-destructive evaluation (NDE) applications. The absence of direct contact or a liquid couplant provides this technique very attractive benefits in front of the well-known and well-developed liquid-coupled ultrasonic inspection systems. A wide range of defects can be detected by means of ultrasound coupled to and harvested from the specimen in absence of contact when using appropriate transducers designed for their operation in air.This paper presents an easy way to integrate air-coupled piezoelectric transducers in conventional ultrasonic NDE equipment. The design of a specific front-end electronics by using an ultra-low noise amplifier enables existing inspection systems to be used for the dry-coupled ultrasonic test of materials and structures. The amplifier provides the receiver with a signal-to-noise ratio large enough for good quality signal processing and imaging. System dynamic ranges of more than 100 dB are achieved. 相似文献
An alternative method for the determination of the kinetic parameters involved in the elementary steps of the reaction mechanism of the hydrogen electrode reaction is proposed. It is based on the determination of the variation of the polarization resistance in a tubular platinum electrode with a laminar flow of electrolyte as a function of the activity of protons of the electrolyte solution. A theoretical expression that relates the experimental variables and the equilibrium polarization resistance is developed, which takes into account the current distribution along the electrode surface. The results are compared with others obtained previously, contributing to the verification of the kinetic mechanism through a completely different experimental procedure. 相似文献
In previous works, many authors have widely used mass consistent models for wind field simulation by the finite element method. On one hand, we have developed a 3-D mass consistent model by using tetrahedral meshes which are simultaneously adapted to complex orography and to terrain roughness length. In addition, we have included a local refinement strategy around several measurement or control points, significant contours, as for example shorelines, or numerical solution singularities. On the other hand, we have developed a 2.5-D model for simulating the wind velocity in a 3-D domain in terms of the terrain elevation, the surface temperature and the meteorological wind, which is consider as an averaged wind on vertical boundaries. Using the meteorological wind as datum, the 2.5-D model provides a 3-D local wind modified by topography and thermal gradients on the surface by solving only a 2-D optimal control problem where the boundary condition is the control. In this case, the finite element discretization consists on a triangular mesh adapted to the terrain topography and roughness length. In both models, the wind field adjusts to several wind speed measurements at several points in the 3-D domain and eventually to an average wind flux on the boundary.In this paper we introduce several advances in the 2.5-D and 3-D wind models and we compare their results on a region located in the Province of Lugo (Spain) with realistic data that have been provided by the company Desarrollos Eólicos S.A. (DESA). In order to obtain the best adjustment of models results to the measurements, the main parameters governing the models are estimated by using genetic algorithms with a parallel implementation. 相似文献
Both cis‐ and trans‐but‐2‐ene‐1,4‐diamines have been prepared and efficiently applied as sacrificial cosubstrates in enzymatic transamination reactions. The best results were obtained with the cis‐diamine. The thermodynamic equilibrium of the stereoselective transamination process is shifted to the amine formation due to tautomerization of 5H‐pyrrole into 1H‐pyrrole, achieving high conversions (78–99%) and enantiomeric excess (up to >99%) by using a small excess of the amine donor. Furthermore, when the reaction proceeded, a strong coloration was observed due to polymerization of 1H‐pyrrole. A structurally related compound, cis‐but‐2‐ene‐1,4‐diol, has been utilized as cosubstrate in different alcohol dehydrogenase (ADH)‐mediated bioreductions. In this case, high conversions (91–99%) were observed due to a lactonization process. Both strategies are convenient from both synthetic and atom economy points of view in the production of valuable optically active products.
