Traffic grooming in WDM optical network with grooming resources at Max Connectivity nodes

In this paper, we propose Max Connectivity grooming in WDM mesh networks under static lightpath connection requests. The grooming and wavelength conversion resources are placed at the nodes having maximum connections. We propose a heuristic genetic algorithm (GA) model to solve grooming, routing and wavelength assignment. The GA algorithm has been used to optimize the cost of grooming and wavelength conversion resources. The blocking probability has been investigated under different lightpath connections. The performance of Max Connectivity grooming has been compared with other grooming policies. Our results indicate the improvement of resource utilization with minimum blocking probability.     

60 GHz indoor WLANs: insights into performance and power consumption

This paper presents a feasibility study of 60 GHz indoor WLANs. We evaluate 60 GHz performance in a typical academic office building under the primary assumption that 60 GHz WLAN APs and clients will be equipped with relatively wide-beam antennas to cope with client mobility. In contrast to previous works which measured performance at a single layer using custom, non-standard compliant hardware, we investigate performance across multiple layers using primarily 802.11ad-compliant wide-beam COTS devices. Our study shows that the large number of reflective surfaces in typical indoor WLAN environments combined with wider beams makes performance highly unpredictable and invalidates several assumptions that hold true in static, narrow-beam, Line-Of-Sight scenarios. Additionally, we present the first measurements, to our best knowledge, of power consumption of an 802.11ad NIC and examine the impact of a number of factors on power consumption.     

Broadband,High‐Speed,and Large‐Amplitude Dynamic Optical Switching with Yttrium‐Doped Cadmium Oxide

Transparent conducting oxides, such as doped indium oxide, zinc oxide, and cadmium oxide (CdO), have recently attracted attention as tailorable materials for applications in nanophotonic and plasmonic devices such as low‐loss modulators and all‐optical switches due to their tunable optical properties, fast optical response, and low losses. In this work, optically induced extraordinarily large reflection changes (up to 135%) are demonstrated in bulk CdO films in the mid‐infrared wavelength range close to the epsilon near zero (ENZ) point. To develop a better understanding of how doping level affects the static and dynamic optical properties of CdO, the evolution of the optical properties with yttrium (Y) doping is investigated. An increase in the metallicity and a blueshift of the ENZ point with increasing Y‐concentrations is observed. Broadband all‐optical switching from near‐infrared to mid‐infrared wavelengths is demonstrated. The major photoexcited carrier relaxation mechanisms in CdO are identified and it is shown that the relaxation times can be significantly reduced by increasing the dopant concentration in the film. This work could pave the way to practical dynamic and passive optical and plasmonic devices with doped CdO spanning wavelengths from the ultraviolet to the mid‐infrared region.     

Channel coding with quadrature-quadrature phase shift-keying(Q2PSK) signals

Channel coding due to trellis modulation has been proved to be useful for bandlimited channels. However, these modulations, mostly designed with n-use of 2D signals, are primarily aimed at coding gain only. It is pointed out that utilization of all available signal dimensions, which is limited by the time-bandwidth product, may improve the bandwidth efficiency and simultaneously bring an additional coding gain. Trellis coding with a spectrally efficient 4D signal set based on Q²PSK is addressed. Without any expansion of the Q ²PSK signal set, a simple hand-designed 16-state trellis code provides a coding gain of 6.02 dB. With the same number of states in G. Ungergoeck's (1982) 8-PSK trellis, the gain is 4.1 dB. In low intersymbol interference situations, the bandwidth efficiency of this coded Q²PSK is twice that of coded 8-PSK; if both operate at 2 b/s Hz and P_b(E)=10^-5, the coded Q²PSK provides a saving of about 4 dB over the coded 8-PSK. Some fully connected trellises with an expanded signal due to 2-use of Q²PSK signals are also presented. Two such codes ar rate-7/8 achieve a gain of 5.45 dB with only eight states     

Software-defined optical networks (SDONs): a survey

This paper gives an overview of software-defined optical networks (SDONs). It explains the general concepts on software-defined networks (SDNs), their relationship with network function virtualization, and also about OpenFlow, which is a pioneer protocol for SDNs. It then explains the benefits and challenges of extending SDNs to multilayer optical networks, including flexible grid and elastic optical networks, and how it compares to generalized multi-protocol label switching for implementing a unified control plane. An overview on the industry and research efforts on SDON standardization and implementation is given next, to bring the reader up to speed with the current state of the art in this field. Finally, the paper outlines the benefits achieved by SDONs for network operators, and also some of the important and relevant research problems that need to be addressed.     

Use of ridge regression for improved estimation of kinetic constants from PET data

The estimation of parameters in radio-tracer models from positron emission tomography (PET) data by nonlinear least squares (NLS) often leads to results with unacceptable mean square error (ME) characteristics. The introduction of constraints on parameters has the potential to address this problem. We examine a ridge-regression technique that augments the standard NLS criterion by the addition of a term which penalizes estimates which deviate from physiologically reasonable values. A variation on a plug-in methodology of Hoerl et al. [7] is examined for data-dependent selection of the degree of reliance to place on the penalizing term. A simulation study is carried out to evaluate the performance of this approach in the context of estimation of kinetic constants in the three-compartment model used to analyze data from PET studies with fluoro-deoxyglucose (FDG). Results show that over a range of realistic noise levels, the ridge-regression procedure can be expected to reduce the root ME of parameter estimates by 60%. This result is not found to be substantially dependent on the precise formulation of the penalty function used. Thus, the use of ridge regression for estimation of kinetic parameters in PET studies is considered to be a promising tool.     

Addressing space‐constraint driven selfishness in smart opportunistic environment

A smart opportunistic environment is a physical space, which allows the smart physical objects to communicate in the presence of disruption in connectivity. Because, the objects in such an environment are buffer constrained, some of the objects will not participate in data forwarding, when there is scarcity of storage (buffer) space. In this paper, we focus on such selfish behavior of objects triggered by space constraints in a smart opportunistic environment. We propose a novel data forwarding algorithm, selfishness and buffer‐aware routing (SBR), in which a node is chosen as a relay, based on its capability, which is a function of its available buffer space and past encounter history (delivery predictability) with the destination. SBR can efficiently utilize the limited buffer space in a node with a buffer management scheme, WSD. It can also detect space constraint driven selfish behavior of nodes and resolve it using a reputation‐based technique, MSD. We have conducted simulation using both synthetic and real‐world traces for evaluating our proposed SBR algorithm. For analyzing the performance of the algorithm in real‐time, a smart vehicular test‐bed is developed. Simulation results and test‐bed implementation show that our algorithm performs better in terms of higher delivery ratio, lower overhead ratio, and lower delivery delay, compared with existing opportunistic data forwarding algorithms.     

Graphene oxide nanoflakes from various agrowastes

Nowadays, the synthesis of graphene/ graphene oxide from graphite precursor using oxidizing agents is the most common procedure, but the direct synthesis of graphene or graphene oxide from a non-graphitic carbonaceous material without using inert atmosphere is really a great challenge. Besides, the chemistry behind the development of graphitic structure from a non-graphitic material during the thermal heating is still not clearly understood. In this research work, three agrowaste materials viz. rice husk, sugarcane bagasse and newspaper were selected and subjected to pyrolysis in presence of trace amount of air. The continued heating at the optimum temperature has resulted in aromatization and condensation along with the oxidation within the cellulosic structure of the agrowaste, which finally resulted in the formation of graphene oxide nanoflakes directly. The mechanism of formation of graphene oxide from these agrowaste materials was studied, which suggested that any carbonaceous waste materials can be converted to graphene oxide by optimizing the thermal heating conditions.     

Functional properties of sonicated and non-sonicated extracted leaf protein concentrate from Diplazium esculentum

Leaf protein concentrate of edible fern Diplazium esculentum was extracted using sonication and non-sonication methods and its functional properties were evaluated. The leaf protein concentrate contained 34.28 and 9.89% protein for sonicated and non-sonicated extractions, respectively. Sonication yielded (36.36%) better emulsion activity over non-sonication (31.10%). Foaming capacity was also found better in sonication (7.27%) over non-sonication (6.99%), and oil absorption capacity also improved in sonication (7.55 g of oil/g) over its counterpart (7.41 g of oil/g). Contact angle experiments with the leaf protein concentrate evidenced the enhancement of more hydrophilicity of the sonicated sample. Thermal properties of the leaf protein concentrate with sonication evidenced more stability (55.58 and 95.95°C) over the non-sonicated (46.75 and 75.60°C). Fourier transform infrared spectral analysis with the leaf protein concentrate of Diplazium esculentum was used to assess the secondary structural data such as α-helix and β-sheets. The various percentages of secondary structures of protein in sonicated and non-sonicated samples were 49.06 and 69.16% for α-helix, 33.59% and 17.02% for β-sheet and 42.02 and 35.68% for turn, respectively. The results of the present investigation showed credible evidence to support that sonication method of extraction of leaf protein concentrate was better in terms of protein yield and functional properties as compared to the non-sonication. The sonicated extracted leaf protein concentrate has the potential for developing value added products.