Fair queueing with service envelopes (FQSE): a cousin-fair hierarchical scheduler for subscriber access networks

In this paper, we propose and investigate the characteristics of a fair queueing with service envelopes (FQSE) algorithm-a hierarchical fair-share scheduling algorithm for access networks based on a remote scheduling system such as Ethernet passive optical networks (EPON) or cable TV network. FQSE is designed to overcome the limiting factors of a typical remote scheduling system such as large control-plane delay, limited control-plane bandwidth, and significant queue switch-over overhead. The algorithm is based on a concept of service envelope-a function representing the fair allocation of resources based on a global network condition called satisfiability parameter (SP). We define properties of cousin-fairness and sibling-fairness and show the FQSE to be cousin-fair. FQSE is unique in that it is the only hierarchical algorithm that is simultaneously cousin-fair. Furthermore, we show the necessary techniques to adapt FQSE to variable-sized packet-based networks. We analyze FQSE performance in EPON serving 1024 independent queues and demonstrate FQSE's ability to provide guaranteed bandwidth to each queue and to share the excess bandwidth fairly.     

A new approach for eliminating unwanted patterns in attenuated phase shift masks

A new approach is identified to eliminate unwanted patterns in high transmission phase shift masks to achieve useful patterning across pitch. A sub-resolution structure is added to the reticle where the propensity of unwanted pattern is found to be maximum. This sub-resolution feature is fully transmitting and has a phase opposite to that of the background. Simulations prove that the light from this feature is successful in nullifying the background intensity responsible for producing the unwanted patterns, while the radiation coming out of the added feature itself gets cancelled and there is no resulting aerial image intensity at the location of the main feature. This technique will help patterning at dense (side lobe prone) pitches even for high transmission masks. Also, the mask-making process will be lot simpler than that of a ternary mask.     

Graph Theory Concepts in Frequency and Availability Analysis

Steady-state availability and failure frequency are two key indices in a repairable system. They are generally evaluated from Markov models with constant transition rates. Numerical solutions can be found for relatively large systems using computer programs. It is more difficult to obtain general equations for a specific system using transition rate symbols. The determination of these equations usually involves linear simultaneous equations, either directly or using Cramer's Rule. This paper describes a general purpose graphical approach for obtaining steady-state availability and frequency expressions from a flow graph based on the Markov model. A set of generalised formulae is developed and applied to several configurations. This technique avoids the need to use matrices for developing general purpose equations. Its direct approach is useful to practising engineers and students of reliability concepts.     

Volatile Constituents of Jambolan (<Emphasis Type="Italic">Syzygium cumini</Emphasis> L.) Fruits at Three Maturation Stages and Optimization of HS-SPME GC-MS Method Using a Central Composite Design

The volatile compounds of jambolan (Syzygium cumini L.) fruit were determined at three different maturity stages (unripe, half-ripe, and ripe) by headspace solid-phase microextraction (HS-SPME)–gas chromatography-mass spectrometry (GC-MS) technique using five different fibers (Fused silica PDMS/DVB, DVB/CAR/PDMS, PEG, Stable flex PDMS/DVB, and PDMS). The optimal extraction conditions were evaluated using different variables such as adsorption temperature (minimum 25 °C, maximum 55 °C), salt quantity (minimum 0, maximum 30.0%), and extraction time (min 10, max 30 min). The major classes of compounds identified were ester, terpene, alcohol, aldehyde, and carboxylic acid. Ninety volatile compounds with characteristics aroma attributes were identified, and the primary compounds linked with development of characteristics aroma of ripe jambolan fruit pulp were trans-β-ocimene, β-ocimene, caryophyllene, humulene, D-α-pinene, L-β-pinene, β-pinene, D-limonene, α-terpineol, neo-allo-ocimene, 2-hexenal (E), δ-cadinene, 3-hexen-1-ol, (Z) β-linalool, terpinolene, eremophilene, valencene, 1-hexanol, longipinene, γ-terpinene, γ-muurolene, endo-borneol, o-cymene, nonanal, terpinen-4-ol, β-terpineol, α-muurolene, fenchol, α-fenchene, β-thujene, benzaldehyde, (E)-2-hexenal, β-cadinene, and decanal.     

Efficacy of continuous wear PureVision contact lenses for therapeutic use.

PURPOSE: To evaluate the Bausch and Lomb PureVision contact lens as continuous wear contact lens for therapeutic and medical indications in a prospective open-ended non-randomized trial. METHODS: Patients who required therapeutic contact lens wear for various indications such as pain relief, corneal protection, persistent epithelial defects, corneal perforation and chemical burns were fitted with PureVision continuous wear contact lenses (balafilcon A, 36% water content). Success or failure of specific treatment indication was assessed in each case with evaluation of ocular and lens related complications. RESULTS: 30 eyes of 28 patients were fitted with PureVision continuous wear contact lenses. A successful fit was seen in 27 of 30 eyes with therapeutic success in 26 of 30 eyes. However, all patients reported symptomatic relief. Duration of lens use ranged from 3 days to 3 months. Dry eye was the most frequent cause of contact lens associated therapeutic failure. Complications included lens loss (two eyes), tight lens (one eye) and infective keratitis (two eyes). CONCLUSIONS: PureVision contact lenses were found to be safe and efficacious for continuous wear therapeutic use to a maximum of 90 days. The contact lens was also easier to handle by virtue of its resilient nature. There were no significant corneal complications of hypoxia, i.e. corneal oedema. Lens losses and deposits were minimal. The lens performance and fitting characteristics compares favorably with previous therapeutic lenses used by the investigators. This new lens may be considered as a safe and effective alternative for use as bandage contact lens.     

Production and structural characterisation of dextran from an indigenous strain of Leuconostoc mesenteroides BA08 in Whey

In this work, the production of dextran was carried out in whey‐supplemented media using Leuconostoc mesenteroides BA08. Different growth and nutritional parameters were optimised to maximise the dextran production. Batch production in whey‐based media under optimised nutritional and growth conditions yielded a dextran concentration of 17.25 g/L. Structural analysis of the purified polymer by FT‐IR, 1D ¹H and ¹³C nuclear magnetic resonance methodology revealed that polymer was a linear dextran having 93% α‐(1→6) linkage in the main chain. The morphology of the dried dextran and dextran‐producing cells was also studied by scanning electron microscope which showed a granular and porous or weblike structure, respectively. The results obtained showed that the industrial whey supplemented with nutrients such as sucrose, yeast extract and K₂HPO₄ can serve as an ideal growth medium for dextran production. The optimised fermentation and nutritional parameters can be further scaled up to establish the potential for the commercial production of food‐grade dextran from whey as part of a novel cost‐effective and environment‐friendly approach.     

Influence of adjuncts as a debittering aids in encountering the bitterness developed in cheese slurry during accelerated ripening

An attempt was made to accelerate the flavour development in cheese base with the help of exogenous proteolytic and lipolytic enzymes (1:1 proportion, each at the rate of 0.025% by weight of cheese‐base) and ripening at elevated temperatures (i.e. 20 ± 1 °C) for up to 12 days. To counter the bitterness developed, adjunct cultures were used: viable or attenuated (freeze‐shocked or heat shocked). Study of biochemical characteristics, electrophoretic pattern and sensory evaluation of the product were carried out. An acceptable enzyme‐modified, lightly salted cheese base was obtained using 0.025% each of proteolytic and lipolytic enzymes, along with 5% starter culture and adjuncts followed by ripening up to 12 days. Freeze‐shocked adjunct Lactobacillus helveticus produced enzyme‐modified cheese base with no detectable bitterness. The usage of exogenous enzymes, temperature of ripening, ripening period and interactions amongst these parameters had significant (P < 0.01) influence on all of the biochemical characteristics monitored.     

Comparative stability of aspartame and neotame in yoghurt

The comparative stability of aspartame and neotame was monitored in yoghurt during its processing, fermentation and storage. A solid‐phase extraction method was suggest changing it to developed for the isolation of aspartame and neotame. Pasteurisation (85 °C/30 min) resulted in approximately 47% and 3% loss of aspartame and neotame, respectively. During fermentation, 3% loss of aspartame was observed, but no loss of neotame. There was no significant effects on the stability of either aspartame or neotame during storage (4–7 °C/15 days). The results indicated that neotame was more stable than aspartame under both pasteurisation and fermentation conditions; however, during storage, both sweeteners exhibited excellent stability.