Hardware design and implementation of packet fair queuing algorithms for the quality of service support in the high-speed internet

The increasing amount of real-time traffic carried over the Internet requires end-to-end quality of service (QoS) support. To this end, the QoS Schedulers, that are implemented in routers, assign the available bandwidth resources to packet flows according to their respective allocated rates. Packet Fair Queuing (PFQ) schedulers can provide fair service and low end-to-end delay bound to the traffic flows. However, they have higher implementation complexity compared to other algorithms, because of the requirements of tracking the system state, and searching for the packet to get service among all flows, that are queued at the outgoing interface. QoS scheduling is a data plane functionality, which requires hardware implementation for high speed router interfaces. The previous works on hardware implementation of PFQ schedulers are specific to certain algorithms, and they do not provide any results on real hardware platforms. In this paper, we present a general hardware design framework for PFQ schedulers, and apply this framework to the WF²Q+ PFQ algorithm to demonstrate its properties. We carry out the entire implementation of the WF²Q+ algorithm on an FPGA, and evaluate its performance with real traffic flows. In addition, we implement WFQ as a second PFQ algorithm to demonstrate the generality of the framework.     

Power quality event detection using joint 2-D-wavelet subspaces

In this work, we present a novel two-dimensional (2-D) representation of power system waveforms for the automatic analysis and detection of transient events. The representation is composed of a matrix whose rows are formed by time segments of digital waveforms. By the appropriate selection of the time segment length, the 2-D data exhibits wave-like image shapes. The general shape is immediately disturbed whenever a power quality transient event occurs. We propose the use of two dimensional discrete wavelet transforms (2-D-DWT) to detect these disturbances. It has been observed that, after omitting the approximation space signals of the wavelet transform and denoising the detail space signals, the inverse 2-D-DWT provides good detection and localization results, even for cases where conventional methods fail. Examples are presented.     

An adaptive statistical method for power quality analysis

Digital fault recorders installed for monitoring current and/or voltage waveforms acquire and store vast amount of waveform data for post processing. Because of this, effective offline automated event detection from acquired data is necessary. In this work, we propose a new automatic event detection method which takes the acquired data and produces event flags at instances of events. The method is based on the statistical analysis of adaptive decomposition signals. The combination of an adaptive prediction filter-based subband decomposition structure with a rule-based histogram analysis block produced successful detection and localization results on our real-life power system transient data.     

The characterizations of rheological,electrokinetical and structural properties of ODTABr/MMT and HDTABr/MMT organoclays

In the present paper, we have investigated as a function of surfactant concentration the rheological (yield value, plastic viscosity) and electrokinetic (mobility, zeta potential) properties of montmorillonite (MMT) dispersions. The influence of surfactants (Octadeccyltrimethylammonium bromide, ODTABr and Hexadecyltrimethylammonium bromide, HDTABr) on dispersions of Na-activated bentonite was evaluated by rheological and electrokinetic measurements, and X-ray diffraction (XRD) studies. The interactions between clay minerals and surfactants in water-based Na-activated MMT dispersions (2 wt.%) were examined in detail using rheologic parameters, such as viscosity, yield point, apparent and plastic viscosity, hysteresis area, and electrokinetic parameters of mobility and zeta potentials, and XRD also analyses helped to determine swelling properties of d-spacings. MMT and organoclay dispersions showed Bingham Plastic flow behavior. The zeta potential measurements displayed that the surfactant molecules hold on the clay particle surfaces and the XRD analyses displayed that they get into the basal layers.     

Antibody arrays prepared by cutinase-mediated immobilization on self-assembled monolayers

Antibody arrays hold considerable potential in a variety of applications including proteomics research, drug discovery, and diagnostics. Many of the schemes used to fabricate the arrays fail to immobilize the antibodies at a uniform density or in a single orientation; consequently, the immobilized antibodies recognize their antigens with variable efficiency. This paper describes a strategy to immobilize antibodies in a single orientation, with a controlled density, using the covalent interaction between cutinase and its suicide substrate. Protein fusions between cutinase and five antibodies of three different types (scFv, V(HH), and FN3) were prepared and immobilized upon self-assembled monolayers (SAMs) presenting a phosphonate capture ligand. The immobilized antibodies exhibit high affinity and selectivity for their target antigens, as monitored by surface plasmon resonance and fluorescence scanning. Furthermore, by changing the density of capture ligand on the SAM the density of the immobilized antibody could be controlled. The monolayers, which also present a tri(ethylene glycol) group, are inert to nonspecific adsorption of proteins and allow the detection of a specific antigen in a complex mixture. The demonstration of cutinase-directed antibody immobilization with insert SAMs provides a straightforward and robust method for preparing antibody chips.     

The rheological properties and characterization of bentonite dispersions in the presence of non-ionic polymer PEG

The effect of poly(ethylene glycol) on the flow behavior of Ca-bentonite and soda activated bentonite dispersions was characterized by the plastic viscosity, the relative viscosity and the yield values. In the range 0.025–12.5 mol/m³, poly(ethylene glycol) (PEG400, PEG3000, PEG8000) was added to bentonite-water systems in different concentrations. Three layered phases with different basal spacings for each Ca- and Na-bentonites were obtained, as shown by XRD studies. The maximum swelling had a basal spacing at 1.82 nm for both PEG400 containing Ca- and Na-bentonites. In addition, expanded basal spacings are displayed at 1.91 nm for Ca- and 2.08 nm for PEG8000 containing Na-bentonites. After the PEG addition, some significant changes in rheological properties were observed; corresponds changes were also found during XRD and IR studies. The results are interpreted according to the type of bentonites, molecular weight of PEG and their concentrations.     

Advanced energy‐based analyses of trusses employing hybrid metaheuristics

Total potential optimization using metaheuristic algorithm (TPO/MA) is an alternative method in structural analyses, and it is a black‐box application for nonlinear analyses. In the study, an advanced TPO/MA using hybridization of several metaheuristic algorithms is investigated to solve large‐scale structural analyses problems. The new generation algorithms considered in the study are flower pollination algorithm (FPA), teaching learning‐based optimization, and Jaya algorithm (JA). Also, the proposed methods are compared with methodologies using classic and previously used algorithms such as differential evaluation, particle swarm optimization, and harmony search. Numerical investigations were carried out for structures with four to 150 degrees of freedoms (design variables). It has been seen that in several runs, JA gets trapped into local solutions. For that reason, four different hybrid algorithms using fundamentals of JA and phases of other algorithms, namely, JA using Lévy flights, JA using Lévy flights and linear distribution, JA with consequent student phase, and JA with probabilistic student phase (JA1SP), are developed. It is observed that among the variants tried, JA1SP is seen to be more effective on approaching to the global optimum without getting trapped in a local solution.     

A review on microalgal growth stress parameters for sustainable biofuel production

Clean Technologies and Environmental Policy - Rapid growth and high carbon-fixation properties make microalgal biomass a preferred source of energy-production technologies, particularly biodiesel...