The MVA Priority Approximation

A Mean Value Analysis (MVA) approximation is presented for computing the average performance measures of closed-, open-, and mixed-type multiclass queuing networks containing Preemptive Resume (PR) and nonpreemptive Head-Of-Line (HOL) priority service centers. The approximation has essentially the same storage and computational requirements as MVA, thus allowing computationally efficient solutions of large priority queuing networks. The accuracy of the MVA approximation is systematically investigated and presented. It is shown that the approximation can compute the average performance measures of priority networks to within an accuracy of 5 percent for a large range of network parameter values. Accuracy of the method is shown to be superior to that of Sevcik's shadow approximation

Performance Analysis of Genetic Algorithm with PSO for Data Clustering

Data clustering is widely used in several areas like machine learning, data mining, pattern recognition, image processing and bioinformatics. Clustering is the process of partitioning or grouping of a given set of data into disjoint cluster. Basically there are two types of clustering approaches, one is hierarchical and the other is partitioned. K-means clustering is one of the partitioned types and it suffers from the fact that that it may not be easy to clearly identify the initial K elements. To overcome the problems in K-means Genetic Algorithm (GA) and Particle Swarm Optimization (PSO) techniques came into existence. A Genetic Algorithm (GA) is one of hierarchical approach and can be noted as an optimization technique whose algorithm is based on the mechanics of natural selection and genetics. Particle Swarm Optimization (PSO) is also one of the hierarchical search methods whose mechanics are inspired by the swarming. The PSO algorithm is simple and can be developed in a few lines of code whereas GAs suffers from identifying a current solution but good at reaching a global region. Even though GA and PSO have their own set of strengths they have weaknesses too. So a hybrid approach (GA-PSO) which combines the advantages of GA and PSO are proposed to get a better performance. The hybrid method merges the standard velocity and modernizes rules of PSOs with the thoughts of selection, crossover and mutation from GAs. A comparative study is carried out by analyzing the results like fitness value and elapsed time of GA-PSO to the standard GA and PSO

REVIEW ON FORMULATION AND EVALUATION OF SOLID LIPID NANOPARTICLES FOR VAGINAL APPLICATION

Vaginal drug administration can improve prophylaxis and treatment of many conditions affecting the female reproductive tract, which includes fungal and bacterial infections, sexually transmitted diseases and cancer also. This is the best route for the administration of proteins, peptides, and also other therapeutic drugs like macro-molecules. For the administration of drugs like contraceptives, steroids, metronidazole, anti-retroviral, vaginal drug delivery is the most preferable route. However, achieving sufficient drug concentration in the vagina can be challenging because of its low permeability. The benefits of the vaginal drug delivery system are it increases the bioavailability, least systemic side effects; easiness of use and self-medication is possible. However vaginal drug delivery system is considered as a less effective route because of the unfortunate absorption of drugs across the vaginal epithelium. The traditional commercial preparations, such as creams, foams, gels, irrigations and tablets, are known to reside in the vaginal cavity for a relatively short period of time owing to the self-cleaning action of the vaginal tract and often require multiple daily doses to ensure the desired therapeutic effect. With the rapidly developing field of nanotechnology, the use of specifically designed carrier systems such as Nanoparticle-based drug delivery has been proven an excellent choice for vaginal application to overcome the challenges associated with the low permeability

Fishery and population dynamics of the obtuse barracuda Sphyraena obtusata (Cuvier) landed by trawlers at Cochin, south-west coast of India

Fishery and population characteristics of the obtuse barracuda Sphyraena obtusata (Cuvier) landed by mechanised trawlers off Cochin were studied for the period 2010-2012. The average annual landings of barracuda was 184 t of which S. obtusata formed 65%. Seasonal peak in catch and catch rate was recorded during August, followed by February and May. The von Bertalanffy growth parameters (VBGF) estimated using ELEFAN were L∞ = 34.2 cm, K = 0.71 year-1 and t0 = -0.0000000025. The lengths attained at the end of 1, 2, 3, 4 and 5 years were 17.4, 25.9, 30.1, 32.2 and 33.2 cm, respectively. Recruitment was almost round the year with a major peak during February-May and a minor peak during July, together accounting 80% of the total recruitment. Natural mortality (M), fishing mortality (F) and total mortality (Z) were 1.35, 1.54 and 2.89 respectively. The length at first capture was 23.5 cm (age 1.64 years). The optimum length for exploitation (Lopt) was 20.9 cm at the age of (topt) of 1.3 years. Mean size in the catch (25.1 cm) was higher than Lopt. The resource is being exploited at a level marginally higher than E50 (E = 0.53), indicating optimal exploitation. Though the annual average yield is only marginally (6%) higher than the MSY estimated, there is no need for reducing the fishing effort from the prevailing rate. Instead, as the yield and biomass per recruit and yield and biomass curves showed that the maximum yield and yield per recruit could be obtained by increasing the present level of fishing, marginal increase in the effort is prescribed to sustain the fishery

Stock dynamics of the brushtooth lizardfish Saurida undosquamis (Richardson, 1848) from a tropical multispecies fishery in the southeastern Arabian Sea

The brushtooth lizardfish Saurida undosquamis (Richardson, 1848) is a high trophic level benthic predator and is one among the most exploited demersal finfish species from eastern Arabian Sea by Indian trawlers. However, in recent years, the landings of many top predator fishes including S. undosquamis showed a declining trend resulting in a steady decline in the mean trophic levels of the fishes caught commercially in the region. We investigated the growth, mortality and stock dynamics of S. undosquamis harvested by mechanised trawls in the southeastern Arabian Sea, using length-based methods for the data collected during 2012–2016. Besides, Bayesian state-space implementation of the Schaefer model (BSM) and catch-based MSY (CMSY) estimation were also made using the data for the period 1985–2016. Total length of the fish ranged from 5.5 to 34.5 cm with average annual mean length of 22.0 cm during 2012–2016. The growth parameters L∞ and K were 37.3 cm and 0.41 year�1, respectively. The natural, fishing and total mortality coefficients were 0.92, 2.58 and 3.5, respectively and exploitation ratio was 0.82. The length at first maturity was estimated at 21.4 cm for females. The mean size in the catch is lower than the optimum length for exploitation. Fisheries reference points (MSY, Fmsy, Bmsy) as well as relative stock size (B/Bmsy) and exploitation (F/Fmsy) estimated from catch data and broad priors for resilience (r), implies an exploitation of 30% below Bmsy level. Results from the length-based Thompson and Bell prediction model indicates that reducing the present level of fishing effort by 40% would lead to a harvest of the species at a sustainable level. As “fishing down food web” is reported in recent years from eastern Arabian Sea, the exploitation of top predators need to be maintained at sustainable levels to prevent ecosystem changes along the region