Software Aging Analysis of Web Server Using Neural Networks

Software aging is a phenomenon that refers to progressive performance degradation or transient failures or even crashes in long running software systems such as web servers. It mainly occurs due to the deterioration of operating system resource, fragmentation and numerical error accumulation. A primitive method to fight against software aging is software rejuvenation. Software rejuvenation is a proactive fault management technique aimed at cleaning up the system internal state to prevent the occurrence of more severe crash failures in the future. It involves occasionally stopping the running software, cleaning its internal state and restarting it. An optimized schedule for performing the software rejuvenation has to be derived in advance because a long running application could not be put down now and then as it may lead to waste of cost. This paper proposes a method to derive an accurate and optimized schedule for rejuvenation of a web server (Apache) by using Radial Basis Function (RBF) based Feed Forward Neural Network, a variant of Artificial Neural Networks (ANN). Aging indicators are obtained through experimental setup involving Apache web server and clients, which acts as input to the neural network model. This method is better than existing ones because usage of RBF leads to better accuracy and speed in convergence.Comment: 11 pages, 8 figures, 1 table; International Journal of Artificial Intelligence & Applications (IJAIA), Vol.3, No.3, May 201

The public library as a critical institution in South Africa's democracy : a reflection

Article published in the online open access journal LIBRIS, Curtin University, Perth, West AustraliaSouth Africa came out of apartheid rule in 1994. This transition has brought with it its own set of challenges including that of access to information, an essential pillar in upholding a democracy. In this transitional period, South Africa is reliant on every possible institution to contribute to the growth of its fledgling democracy. It is clearly evident from the literature that democratic societies are dependent on such institutions as public libraries to uphold fundamental principles of democracy. This paper reflects on the public library, within the South African context, as an essential institution in the growth and sustainability of democracy through equitable access to information and knowledge. The paper discusses issues such as the public library and its role in equitable access to information, the contradictory environments within South Africa, recreational reading and the public library scenario, lifelong learning, and the public library and the educational system. Other issues such as support for indigenous materials and adult literacy are also addressed in the paper. The authors conclude that the real concern in South Africa today is the gulf between the “haves”, of any colour, and the “have-nots” and the capacity of the public library to bridge that gap via its contribution to the reduction of illiteracy, poverty and unemployment, the scourge of Africa and South Africa. It is a given that public libraries play a critical role in the propagation of democracy, especially in a continent that has been plagued by dictatorships and military rule

Current-induced phase control in charged-ordered Nd0.5Ca0.5MnO3 and Pr0.6Ca0.4MnO3 crystals

Single crystals of Nd0.5Ca0.5MnO3 and Pr0.6Ca0.4MnO3 show current-induced insulator-metal transitions at low temperatures. In addition, the charge-ordering transition temperature decreases with increasing current. The electroresistive ratio, defined as r0.5/rI where r0.5 is the resistivity at a current of 0.5 mA and rI the resistivity at a given applied current, I, varies markedly with temperature and the value of I. Thermal hysteresis observed in Nd0.5Ca0.5MnO3 and Pr0.6Ca0.4MnO3 at the insulator-metal transition indicates that the transition is first-order. The current-induced changes are comparable to those induced by magnetic fields, and the insulator-metal transition in Pr0.6Ca0.4MnO3 is accordingly associated with a larger drop in resistivity.Comment: 12 pages, 3 figures, first submitted to submitted to J. Phys. D; applied physics on 18th march 200

Water distribution rules and water distribution performance: a case study in the Tambraparani Irrigation System

Irrigation management / Irrigation systems / Performance / Irrigation operation / Irrigation scheduling / Water distribution / Water allocation / Water delivery / Water users' associations / Legislation / Large-scale systems / Bananas / Case studies / India / Tamil Nadu / Tambraparani Irrigation System

Effectiveness of lending for vocational education and training: lessons from World Bank experience

This paper reviews the Bank involvement in the vocational education and training (VET) sub-sector in the 1990s. The paper aims to do just that, by mainly seeking answers to the following questions: 1) How has the Bank performed in its lending services to its clients in VET? 2) How have VET projects performed in terms of meeting stated objectives? 3) What factors led to the success, or failure of Bank operations? Based on what has been learned, the paper provides suggestions about how the performance of future VET interventions can be improved. This review concerns itself primarily with implementation performance, and proposes measures to improve project outcomes.ICT Policy and Strategies,Health Economics&Finance,Health Monitoring&Evaluation,Teaching and Learning,Banks&Banking Reform

Trust Based Participant Driven Privacy Control in Participatory Sensing

Widespread use of sensors and multisensory personal devices generate a lot of personal information. Sharing this information with others could help in various ways. However, this information may be misused when shared with all. Sharing of information between trusted parties overcomes this problem. This paper describes a model to share information based on interactions and opinions to build trust among peers. It also considers institutional and other controls, which influence the behaviour of the peers. The trust and control build confidence. The computed confidence bespeaks whether to reveal information or not thereby increasing trusted cooperation among peers.Comment: 14 page

New Recursion Relations and a Flat Space Limit for AdS/CFT Correlators

We consider correlation functions of the stress-tensor or a conserved current in AdS_{d+1}/CFT_d computed using the Hilbert or the Yang-Mills action in the bulk. We introduce new recursion relations to compute these correlators at tree level. These relations have an advantage over the BCFW-like relations described in arXiv:1102.4724 and arXiv:1011.0780 because they can be used in all dimensions including d=3. We also introduce a new method of extracting flat-space S-matrix elements from AdS/CFT correlators in momentum space. We show that the (d+1)-dimensional flat-space amplitude of gravitons or gluons can be obtained as the coefficient of a particular singularity of the d-dimensional correlator of the stress-tensor or a conserved current; this technique is valid even at loop-level in the bulk. Finally, we show that our recursion relations automatically generate correlators that are consistent with this observation: they have the expected singularity and the flat-space gluon or graviton amplitude appears as its coefficient.Comment: 22+6 pages (v2) typos fixe

Production and Growth of Pulses in Telangana State: An Economic Analysis

Pulses are the most important for Indian diet and the principal source of protein for the poor people and the vegetarians. India is at the high among all the major pulse producing nations in the world. The present investigation is an attempt to examine the pattern of growth and instability in the cropped area, production and productivity of major pulse crops in Telangana state. The annual time series of data form the period 1980 to 2015 relating to the area, production and productivity of major pulse crops have been used to compute growth rates, standard deviation and coefficient of variation to realize the objectives. The results of the study reveal that there have been positive changes in the area of pulse crops. The annual average growth rate in the area was estimated to be 0.05%, 0.01%, -0.03% and 0.02% in Bengal gram, black gram, green gram and red gram respectively. The production growth rate in the same pulse crops was presented to be 0.83%, 0.20%, 0.13% and 0.17% as the average annual growth rate in the State. The productivity growth rate for these crops was further assessed to be 0.18%, 0.13%, 0.10% and 0.15%, respectively. The instability in the area was observed to be high in green gram followed by red gram and bengal gram and minimum in black gram. Similarly, instability in productivity was also found to be high in bengal gram and minimum in green gram. Further, variability in production was also observed to be maximum in bengal gram followed by the red gram, and green gram and minimum in black gram, respectively

Biophysical investigation of novel cryoprotectants

This thesis aims to examine the critical molecular properties that lead to good cryoprotective performance and use this knowledge to test novel non-toxic compounds which can be optimized to use as cryoprotectants (CPAs). The key properties needed to make a good CPA are: low toxicity; the ability to pass through membranes to get inside cells; the ability to form glasses at relatively high sub-zero temperatures; and the ability to inhibit ice recrystallisation during thawing (the growth of larger ice crystals from smaller ones). This thesis presents a systematic investigation of these important properties, for both traditional CPAs and novel compounds with cryoprotective potential. Cryopreservation trials with some of these compounds are carried out to assess their cryoprotective potential. First, this thesis presents a Langmuir monolayer study of the effects of four common cryoprotective agents (dimethyl sulfoxide, ethylene glycol, glycerol and dimethyl formamide) on phospholipid monolayers. Four different phospholipids (DOPC, DPPC, POPC, POPE) are studied to determine if the head group and level of chain saturation influence the interactions. It is shown that the phospholipid species can have a significant effect. DMSO showed interesting lipid specific effects - causing expansion of DPPC monolayers but compression for POPC monolayers, while having little effect for DOPC and POPE. The results highlight the importance of studying more than one model lipid system as well as the need to study concentrations relevant to cryopreservation. Second, this thesis investigates the potential of carbohydrate-based surfactants such as n- octyl(thio)glycosides to be a novel and accessible class of penetrating CPAs. A series of eight n-octyl (thio)glycosides (1alpha/beta - 4alpha/beta) with D-glucose or D-galactose-configured head groups and varying anomeric configurations were evaluated for glass transition behavior and membrane permeability. Of these, n-octyl beta-D-glucopyranoside (2beta) exhibited high glass transition temperature (Tg), both as a neat sample and 20wt-% aqueous solution. Membrane permeability studies of this compound revealed cellular uptake at concentrations relevant to the inhibition of intracellular ice formation, thus presenting a promising lead candidate for further biophysical and cryopreservation studies. Third, this thesis presents similar studies on four trehalose derivatives in order to understand their cryoprotective potential. Permeability trials on these molecules showed that trehalose-di acetate has no cell permeability, whereas both trehalose di pivotate and trehalose tetra acetate have moderate permeability. The most promising candidate with high glass transition temperature and relatively good permeability was trehalose di pivotate, so this compound was used for further cryopreservation studies on THP-1 cells. Finally, this thesis presents the development of a novel microfluidic cell trapping device for cell permeability studies, which has considerable advantages over traditional techniques. Two microfluidic cell trapping structures were produced, combining direct laser writing (DLW) and soft lithography techniques. These structures were used for the hydrodynamic capturing of single human monocyte (THP-1) cells and tested by studying the cell volume kinetics upon the addition of DMSO. Compared to existing technologies, the method allowed: (i) rapid capture of single cells without surface functionalization; (ii) the rapid exchange of solvent to generate osmotic gradients across the cell membrane; and (iii) real-time imaging of cells during the shrinkage and swelling phases due to the imaging stability provided by the traps. To date, the search for new CPAs has been reliant on educated guesswork and trial and error. This thesis systematically investigates the critical molecular properties relevant for cryopreservation and provides a systematic method for assessing novel molecules as alternative cryoprotectants