Redundancy Strategies for a High Splitting Optically Amplified Passive Optical Network

Copyright IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.High splitting, optically amplified, passive optical networks (SuperPONs) are investigated in terms of redundancy provision and protection mechanisms. Options for redundancy, including the important special case of dual homing, are detailed, and it is determined as to which of these options (duplication of the feeder and first distribution section, and N+1 protection of the optical amplifiers in the amplified splitter) would be required to be provided to all attached users to facilitate appropriate availability of the basic telephony service. The distributed amplified splitter dual homing solution is found to outperform the single amplified splitter solution in terms of its survivability. The protection mechanisms necessary to automatically switch to the redundant provision are discussed and it is seen that with the aid of suitable regular precautionary procedures protection switching can generally be provided rapidly (<50 ms). Finally, an availability, and cost versus availability, study confirms the aforementioned redundancy assessment for fiber-to-the-home (FTTH) implementations, but shows fiber-to-the-curb (FTTC) as needing additional redundancyPeer reviewe

A Method For Relating GPS Performance To Forest Canopy

This paper describes the development of a quantitative method of classifying forest canopy that can be related to degradation in Differential GPS (DGPS) performance. Using digital images taken vertically skywards at 20 sites within a forest on the east coast of Ireland, canopy cover was described using percentage sky obstruction (Op), largest hole (DTmax), and the fragmentation of sky view (DTp) using pixel count and distance transform data. Statistical methods were used to produce three clusters which related to canopy cover in stands of Picea sitkensis and Picea contorta. DGPS data were then collected on 10 separate dates at the 20 sites, every two seconds for five minutes, and the two-dimensional standard deviation of the position fix was used to represent DGPS precision. The standard deviations ranged from 0.5 m to 9.7 m (compared to the manufacturer's specification of approximately 1 m in the horizontal). Precision was found to be related to the total obstruction, the size of the largest hole in the canopy, and the fragmentation of the sky view. Where there was little obstruction (less than 20%) or fragmentation, the DGPS performance was effectively the same as outside the forest, open canopy caused a 2-3 fold degradation in precision, and closed canopy a 5-7 fold degradation. It is suggested that the methods presented could be used to rapidly relate DGPS performance to forest canopy, and therefore may be useful in pre-planning inventory mapping and future machine operations using guidance systems

Diffusion of Aspirin (ASA) Based Drugs in Sodium Hydroxide Solution at Ambient Temperature.

Diffusion is a macroscopic motion of components of a system that arises from concentration difference and plays a vital role in drug migration in the body governed by Fickian diffusion laws. This project considers effective mechanism leading to effective diffusion coefficient. The diffusion coefficient of aspirin based drugs was studied in basic NaOH of concentration range 0.01M to 0.1M and a relatively more concentrated set ranging from 0.1M to 1.0M were studied at 25oC. The study looks into the rate of diffusion of coated and non-coated aspirin drugs in aqueous NaOH solution designated different letter heads A, B, C, D, and E. The objective of this work was to determine the diffusion coefficients of aspirin drugs at different concentrations range at 25oC and to compare with those calculated from limiting ionic conductance at infinite dilution. The rate of diffusion was monitored by observing the boundary conditions of the indicator between the drug and solution. The problem statement is that there are various aspirin based drugs in the market and all have different amount of aspirin in them. The research sought to find out the rate of diffusion of the drugs and conclude if at all their values relate to their masses as per the diffusion law. In the study five (5) aspirin tablets collected from a local pharmacy in Eldoret town were used for the study. From the profile it was observed that as the time progressed the boundary increased fast for noncoated tablets compared to the coated ones. The boundary heights (x) at a time t and concentration are also recorded. The moving boundary method coefficients ranged from 2.780 x 10-6 cm2 sec-1 to 6.995 x 10-6 cm2 sec- 1, 2.196 x 10-6 cm2 sec-1 to 6.092 x 10-6 cm2 sec-1, 2.138 x 10-7 cm2 sec-1 to 6.576 x 10-7 cm2 sec-1 , 3.241 x 10-10 cm2 sec-1 to 1.617 x 10-10 cm2 sec-1 and 1.378 x 10-10 cm2 sec-1 to 2.172x 10-10 cm2 sec-1 for drugs aspirin A , B, C. D and E respectively. All the aspirin were found to give values according to Fickian mechanism. For the drug A (600mg) of aspirin the best value of diffusion coefficient of 6.995 x 10-6 cm2 sec-1 at concentrated solution and 2.780 x 10-6 cm2 sec-1 was observed at dilute range solutions while the values for coated drug E with 75 mg aspirin was found to be slightly lower. The fractional drug uptake is linear and independent of the sample of thickness when distance is plotted against time. A graph of x2 against time was plotted which was used to calculate the diffusion coefficient. The experimental values of diffusion coefficient Do were in close agreement with the expected value from infinite dilution which was a general estimation of diffusion coefficients. Quantitative data was analysed using analysis of variance and chi-square statistical. Data was presented using table and graphs. The study found that the aspirin drug with the highest diffusion coefficient is drug A. In addition, conductometric technique was recommended to give more accurate results and similar method should be constituted with the use of other techniques such as TLC and spectrophotometric method for comparison purposes with the free diffusion and it is important for manufacturers to revalidate steps in the production process, for any critical control point in the production process leads to hydrolysis of aspirin. Key words: Diffusion, Aspirin, Acetylsalicylic acid, Diffusion Coefficient, Sodium Hydroxide, Fickia

Detuning effects in the one-photon mazer

The quantum theory of the mazer in the non-resonant case (a detuning between the cavity mode and the atomic transition frequencies is present) is written. The generalization from the resonant case is far from being direct. Interesting effects of the mazer physics are pointed out. In particular, it is shown that the cavity may slow down or speed up the atoms according to the sign of the detuning and that the induced emission process may be completely blocked by use of a positive detuning. It is also shown that the detuning adds a potential step effect not present at resonance and that the use of positive detunings defines a well-controlled cooling mechanism. In the special case of a mesa cavity mode function, generalized expressions for the reflection and transmission coefficients have been obtained. The general properties of the induced emission probability are finally discussed in the hot, intermediate and cold atom regimes. Comparison with the resonant case is given.Comment: 9 pages, 8 figure

Equianalytic and equisingular families of curves on surfaces

We consider flat families of reduced curves on a smooth surface S such that each member C has the same number of singularities of fixed singularity types and the corresponding (locally closed) subscheme H of the Hilbert scheme of S. We are mainly concerned with analytic resp. topological singularity types and give a sufficient condition for the smoothness of H (at C). Our results for S=P^2 seem to be quite sharp for families of cuves of small degree d.Comment: LaTeX v 2.0

Parental vitamin deficiency affects the embryonic gene expression of immune-, lipid transport- and apolipoprotein genes

World Health Organization is concerned for parental vitamin deficiency and its effect on offspring health. This study examines the effect of a marginally dietary-induced parental one carbon (1-C) micronutrient deficiency on embryonic gene expression using zebrafish. Metabolic profiling revealed a reduced 1-C cycle efficiency in F(0) generation. Parental deficiency reduced the fecundity and a total of 364 genes were differentially expressed in the F(1) embryos. The upregulated genes (53%) in the deficient group were enriched in biological processes such as immune response and blood coagulation. Several genes encoding enzymes essential for the 1-C cycle and for lipid transport (especially apolipoproteins) were aberrantly expressed. We show that a parental diet deficient in micronutrients disturbs the expression in descendant embryos of genes associated with overall health, and result in inherited aberrations in the 1-C cycle and lipid metabolism. This emphasises the importance of parental micronutrient status for the health of the offspring

A machine learning approach for real-time wheel-rail interface friction estimation

Predicting friction at the wheel-rail interface is a key problem in the rail industry. Current forecasts give regional-level predictions, however, it is well known that friction conditions can change dramatically over a few hundred meters. In this study, we aimed to produce a proof-of-concept friction prediction tool which could be used on trains to give an indication of the limiting friction present at a precise location. To this end, field data including temperature, humidity, friction, and images were collected. These were used to fit a statistical model including effects of local environmental conditions, surroundings, and railhead state. The model predicted the friction well with an R2 of 0.97, falling to 0.96 for naive models in cross validation. With images and environmental data collected on a train, a real-time friction measurement would be possible

Control of an atom laser using feedback

A generalised method of using feedback to control Bose-Einstein condensates is introduced. The condensates are modelled by the Gross-Pitaevskii equation, so only semiclassical fluctations can be suppressed, and back-action from the measurement is ignored. We show that for any available control, a feedback scheme can be found to reduce the energy while the appropriate moment is still dynamic. We demonstrate these schemes by considering a condensate trapped in a harmonic potential that can be modulated in strength and position. The formalism of our feedback scheme also allows the inclusion of certain types of non-linear controls. If the non-linear interaction between the atoms can be controlled via a Feshbach resonance, we show that the feedback process can operate with a much higher efficiency.Comment: 6 pages, 7 figure

Spontaneous non-traumatic splenic artery aneurysm rupture: a case report and review of the literature.

The current case report is about spontaneous non-traumatic rupture of a splenic artery aneurysm (SAA) in a 53-year-old woman with no particular medical history. An emergent laparotomy with splenectomy was required, unfortunately without success as the patient died. SAA is the most common visceral artery aneurysm. Most of SAA remain asymptomatic and are discovered incidentally on imaging. The overall risk of rupture increases with the size of SAA, especially when above 2 cm. Initial presentation of SAA has been associated with acute rupture and hemodynamic instability leading to substantial perioperative morbidity and mortality

Diagnostic ability of multifocal electroretinogram in early multiple sclerosis using a new signal analysis method

Purpose To determine if a novel analysis method will increase the diagnostic value of the multifocal electroretinogram (mfERG) in diagnosing early-stage multiple sclerosis (MS). Methods We studied the mfERG signals of OD (Oculus Dexter) eyes of fifteen patients diagnosed with early-stage MS (in all cases &lt; 12 months) and without a history of optic neuritis (ON) (F: M = 11:4), and those of six controls (F:M = 3:3). We obtained values of amplitude and latency of N1 and P1 waves, and a method to assess normalized root-mean-square error (FNRMSE) between model signals and mfERG recordings was used. Responses of each eye were analysed at a global level, and by rings, quadrants and hemispheres. AUC (area under the ROC curve) is used as discriminant factor. Results The standard method of analysis obtains further discrimination between controls and MS in ring R3 (AUC = 0.82), analysing N1 waves amplitudes. In all of the retina analysis regions, FNRMSE value shows a greater discriminating power than the standard method. The highest AUC value (AUC = 0.91) was in the superior temporal quadrant. Conclusion By analysing mfERG recordings and contrasting them with those of healthy controls it is possible to detect early-stage MS in patients without a previous history of ON