272 research outputs found
Autonomous grid scheduling using probabilistic job runtime scheduling
Computational Grids are evolving into a global, service-oriented architecture ā
a universal platform for delivering future computational services to a range of
applications of varying complexity and resource requirements. The thesis focuses
on developing a new scheduling model for general-purpose, utility clusters
based on the concept of user requested job completion deadlines. In such a
system, a user would be able to request each job to finish by a certain deadline,
and possibly to a certain monetary cost. Implementing deadline scheduling is
dependent on the ability to predict the execution time of each queued job, and
on an adaptive scheduling algorithm able to use those predictions to maximise
deadline adherence. The thesis proposes novel solutions to these two problems
and documents their implementation in a largely autonomous and self-managing
way.
The starting point of the work is an extensive analysis of a representative
Grid workload revealing consistent workflow patterns, usage cycles and correlations between the execution times of jobs and its properties commonly collected
by the Grid middleware for accounting purposes. An automated approach is
proposed to identify these dependencies and use them to partition the highly
variable workload into subsets of more consistent and predictable behaviour.
A range of time-series forecasting models, applied in this context for the first
time, were used to model the job execution times as a function of their historical
behaviour and associated properties. Based on the resulting predictions of job
runtimes a novel scheduling algorithm is able to estimate the latest job start
time necessary to meet the requested deadline and sort the queue accordingly to
minimise the amount of deadline overrun.
The testing of the proposed approach was done using the actual job trace
collected from a production Grid facility. The best performing execution time
predictor (the auto-regressive moving average method) coupled to workload
partitioning based on three simultaneous job properties returned the median
absolute percentage error centroid of only 4.75%. This level of prediction
accuracy enabled the proposed deadline scheduling method to reduce the average deadline overrun time ten-fold compared to the benchmark batch scheduler.
Overall, the thesis demonstrates that deadline scheduling of computational
jobs on the Grid is achievable using statistical forecasting of job execution times
based on historical information. The proposed approach is easily implementable,
substantially self-managing and better matched to the human workflow making
it well suited for implementation in the utility Grids of the future
Terapija endometritisa krmaÄa intrauterinom instilacijom preparata na bazi zida kvasca
On the basis of our investigations it was possible to conclude that intrauterine treatment of sows with puerperal uterine infections with sterile YCW (Yeast Cell Wall) resulted in significant clinical improvement. The percent of recidivism was the lowest (10%) in groups of sows treated with 10 and 20 g of YCW. The degree of bacterial CFU (Colony Forming Units) reduction in samples of sows uterine flushings following instillation of YCW (5, 10 and 20 g) was wery high and ranged from 1361 to 1444 times, while in sows treated with Lotagen 2% solution (100 mL) this parametar was only 32. At the moment of weaning, piglets from sows treated with 10 and 20 g of YCW were heavier when compared to the control and Lotagen group and their DBWG (Daily Body Weight Gain) was higher when compared to the Lotagen and control group. Treatment of sows by IU instillation of YCW did not influence the number of piglets in the next breeding cycle.Na osnovu rezultata naÅ”ih istraživanja bilo je moguÄe zakljuÄiti da tretman krmaÄa obolelih od puerperalnih infekcija materice, sterilnim preparatom dobijenim iz zida kvasca (YCW), ima za posledicu znaÄajan kliniÄki napredak. Procenat krmaÄa sa recidivom je bio najniži (10%) u grupi tretiranoj sa 10 i 20g YCW. Stepen redukcije broja bakterijskih kolonija (CFU) u uzorcima dobijenih iz materice krmaÄa posle tretmana YCW preparatom je bio veoma visok i kretao se u opsegu od 1361 do 1444 puta. Kod obolelih krmaÄa, tretiranih rastvorom Lotagena (2%), vrednost ovog parametra je bila svega 32. U momentu zaluÄenja, prasad krmaÄa tretiranih YCW preparatom u koliÄini od 10 i 20 g bila su teža u poreÄenju sa prasadima krmaÄa grupe tretirane Lotagenom i prasadima kontrolnih (neteretiranih) krmaÄa. Osim toga i njihovi proseÄni dnevni prirasti su bili veÄi. Tretman krmaÄa intrauterinom instilacijom preparata na bazi YCW nije negativno uticao na broj prasadi u sledeÄem reproduktivnom ciklusu
Characterization of nanostructured spinel NiFe2O4 obtained by soft mechanochemical synthesis
Powdery nickel ferrite, NiFe2O4 has been obtained by soft mechanochemical synthesis in a planetary ball mill. Ni(OH)2 and Fe(OH)3 are used as initial compounds. This mixture was mechanically activated for 25h, uniaxial pressed and sintered at 1100Ā°C for 2h. The phase composition of the sintered sample was analyzed by X-ray diffraction (XRD), energy dispersive spectrometer (EDS) and Raman spectroscopy. Morphologies were examined by scanning electron microscopy (SEM). The electrical DC/resistivity/conductivity at different temperatures was measured using a Source Meter Keithley 2410. An Impedance/Gain-Phase Analyzer (HP-4194) was used to measure the impedance spectra (100Hz - 10MHz) at different temperatures. [Projekat Ministarstva nauke Republike Srbije, br. III 45003 i br. III 45015
Further results on non - Lyapunov stability of the linear nonautonomous systems with delayed state
Ovaj rad predstavlja dalji rad na osnovnim rezultatima u oblasti ograniÄenog vremena i praktiÄne stabilnosti linearnih, kontinualnih stacionarnih, neautonomnih sistema sa kaÅ”njenjem. Izdvojeni su dovoljni uslovi ovog tipa stabilnosti za odreÄenju klasu sistema sa kaÅ”njenjem. .Paper extends some basic results from the area of finite time and practical stability to linear, continuous, time invariant nonautonomous time-delay systems. Sufficient conditions of this kind of stability, for particular class of time-delay systems are derived.
Further results on non - Lyapunov stability of the linear nonautonomous systems with delayed state
Ovaj rad predstavlja dalji rad na osnovnim rezultatima u oblasti ograniÄenog vremena i praktiÄne stabilnosti linearnih, kontinualnih stacionarnih, neautonomnih sistema sa kaÅ”njenjem. Izdvojeni su dovoljni uslovi ovog tipa stabilnosti za odreÄenju klasu sistema sa kaÅ”njenjem. .Paper extends some basic results from the area of finite time and practical stability to linear, continuous, time invariant nonautonomous time-delay systems. Sufficient conditions of this kind of stability, for particular class of time-delay systems are derived.
Analysis of thick plates by a finite space element
U radu su prikazane moguÄnosti prostornog konaÄnog elementa velike toÄnosti u linearnoj analizi ploÄa proizvoljne ali konstantne debljine. Primijenjen je pravokutni trikubiÄni Lagrangeov element s 192 kinematiÄka stupnja slobode. Opisano je analitiÄko rjeÅ”enje bisinusoidalnog savijanja zglobno oslonjene ploÄe i pripadni numeriÄki model. Rezultati usporedbe analitiÄkog i numeriÄkog rjeÅ”enja pokazuju visoki stupanj toÄnosti pomaka i naprezanja dobivenih numeriÄkim proraÄunom.Possibilities of using a highly accurate finite space element in the linear analysis of plates of arbitrary but constant thickness are presented in the paper. The rectangular three cubical Lagrange element with 192 kinematic degrees of freedom is applied in the analysis. The analytical solution for bisinusoidal bending of a hinged plate, as well as an appropriate numerical model, are described. The comparison of analytical and numerical solutions shows a high level of accuracy as to displacement and stress values obtained by numerical analysis
Short-term liquid storage of ram semen in various extenders
The aim of this study was to investigate the effects of three extenders on ram sperm quality after short-term liquid storage (24 hoursā holding time). The study included 20 crossbred rams (Pirot Pramenka x Wurttemberg x Ile de France), 12 months old. Animals were housed at the experimental sheep farm of the Institute for Animal Husbandry in Belgrade, Serbia. Semen was collected through electro ejaculation. The ejaculates were obtained from single services and routine field analysis of the semen was performed immediately after the collection. The semen was split and diluted with three extenders, namely OptidylĀ®, AndromedĀ® and ultrahigh temperature processed (UHT) milk, in ratios of 1 : 50 or 1 : 100. The ejaculates were examined for sperm motility variables (sperm cell motility percentage, the progressive motility percentage, curvilinear velocity (VCL), straight line velocity (VSL), average path velocity (VAP), sperm linearity (LIN), straightness (STR), amplitude of lateral sperm head displacement (ALH), beat cross frequency (BCF) and circular tracks), and sperm morphology (live sperm percentage, percentage of normal sperm forms with intact acrosome, percentage of abnormal sperm forms and total damaged acrosome) by computer-assisted sperm analysis (CASA) and classic sperm cytology after supravital eosin/nigrosine/trypan blue staining, respectively. It was observed that the type of extender used in diluting ram semen is an important factor in the successful short-term liquid preservation (at 4 Ā°C) of ram spermatozoa. In conclusion, this study showed that egg yolk (Optidyl) and soybean (Andromed)-based extenders gave better results of both sperm morphology and sperm motility parameters compared with UHT milk.Keywords: Diluents, morphology, motility, sper
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