Generalizing List Scheduling for Stochastic Soft Real-time Parallel Applications

Advanced architecture processors provide features such as caches and branch prediction that result in improved, but variable, execution time of software. Hard real-time systems require tasks to complete within timing constraints. Consequently, hard real-time systems are typically designed conservatively through the use of tasks? worst-case execution times (WCET) in order to compute deterministic schedules that guarantee task?s execution within giving time constraints. This use of pessimistic execution time assumptions provides real-time guarantees at the cost of decreased performance and resource utilization. In soft real-time systems, however, meeting deadlines is not an absolute requirement (i.e., missing a few deadlines does not severely degrade system performance or cause catastrophic failure). In such systems, a guaranteed minimum probability of completing by the deadline is sufficient. Therefore, there is considerable latitude in such systems for improving resource utilization and performance as compared with hard real-time systems, through the use of more realistic execution time assumptions. Given probability distribution functions (PDFs) representing tasks? execution time requirements, and tasks? communication and precedence requirements, represented as a directed acyclic graph (DAG), this dissertation proposes and investigates algorithms for constructing non-preemptive stochastic schedules. New PDF manipulation operators developed in this dissertation are used to compute tasks? start and completion time PDFs during schedule construction. PDFs of the schedules? completion times are also computed and used to systematically trade the probability of meeting end-to-end deadlines for schedule length and jitter in task completion times. Because of the NP-hard nature of the non-preemptive DAG scheduling problem, the new stochastic scheduling algorithms extend traditional heuristic list scheduling and genetic list scheduling algorithms for DAGs by using PDFs instead of fixed time values for task execution requirements. The stochastic scheduling algorithms also account for delays caused by communication contention, typically ignored in prior DAG scheduling research. Extensive experimental results are used to demonstrate the efficacy of the new algorithms in constructing stochastic schedules. Results also show that through the use of the techniques developed in this dissertation, the probability of meeting deadlines can be usefully traded for performance and jitter in soft real-time systems

OPTIMIZATION OF CAPILLARY ACTION & BRASS CONSUMPTION IN DIP-BRAZING OF ROADSTER BICYCLE FRAMES

This paper describes the requirements of joint clearance between the mating parts, of lugged bicycle frame head, to be brazed by flow of molten filler material (brass) between the micro gap due to capillary action. Tolerance analysis was done to establish the practical requirements of clearances essential to facilitate the assembly of the bicycle frame tubes and mating head lugs. Consumption of brass was computed, by weight measurements, after dip brazing of the lugged joints. Excessive joint clearance between the mating parts was reduced, by cold compaction of the assembled joint on mechanical power press using a press tool. The compacted joints were dip brazed by dipping it partially in the molten brass. Comparison of tensile strength of the brazed joints was done with respect to the strength of parent steel tubes. Brazed samples were sectioned to confirm the flow of brass all along the length of the lugs with improved capillary action. Thickness of the micro layer of the brass between the lug bore and tube outer surface was measured on optical microscope. Reduction in brass consumption due to reduced clearance was estimated volumetrically between the contact area between the lugs and the tubes

Structural examination of historical heritage bridges

Culture and heritage are important aspects of a civilization after meeting basic needs. The heritage structures also called monuments are generally quite old and may be ever older than hundred years. In case of bridges, the life span as stated by codes/ standards is 50 years to 75 years. Further, the material used in heritage structures are unique in sense the composition at the time of construction is generally not available. Therefore, it is a challenging task to assess the performance of the heritage structures including bridges. In this respect, some of the heritage bridge s in Delhi have been studied and results of one bridge connecting the Red fort and Salimgarh fort namely Mangi Bridge are discussed. The methodology of study involves collection of site data (geometry), numerical modelling, experimental studies at the site and useful inferences. The vibration study and the ongoing traffic affects the bridge as the bridge lies on the major arterial road called Ring Road in Delhi. The study will be helpful for continued use of the bridge

Structural examination of historical heritage bridges

76-79Culture and heritage are important aspects of a civilization after meeting basic needs. The heritage structures also called monuments are generally quite old and may be ever older than hundred years. In case of bridges, the life span as stated by codes/ standards is 50 years to 75 years. Further, the material used in heritage structures are unique in sense the composition at the time of construction is generally not available. Therefore, it is a challenging task to assess the performance of the heritage structures including bridges. In this respect, some of the heritage bridge s in Delhi have been studied and results of one bridge connecting the Red fort and Salimgarh fort namely Mangi Bridge are discussed. The methodology of study involves collection of site data (geometry), numerical modelling, experimental studies at the site and useful inferences. The vibration study and the ongoing traffic affects the bridge as the bridge lies on the major arterial road called Ring Road in Delhi. The study will be helpful for continued use of the bridge

Нормативно-правові аспекти дослідження витрат торговельних підприємств

У статті досліджено міжнародні та національні нормативно-правові акти, що розкривають суть та методологічні аспекти формування витрат підприємств у бухгалтерському і податковому обліку. (In the article are investigated standard-legal sources that open methodological aspects of formation of costs of the enterprises in the accounting and tax account.

Viscosities for binary liquid mixtures of some cellosolves with water at 298.15 K

1120-1123Viscosities (η) of three binary mixtures (cello-solve + water) have been measured as a function of mole fraction at 298.15 K using an Ubbelohde viscometer. The cellosolves were 2-[2-(2-methoxyethoxy)ethoxy] ethanol, 2-[2-(2-ethoxyethoxy )ethoxy]ethanol, and 2-[2-(2-butoxyethoxy)ethoxy]ethanol. From the experimental results, excess logarithmic viscosities (In ηE) and excess energies of activation for viscous flow (G *E) have been calculated. All the mixtures show positive excess functions over the entire concentration range and which increase as the aliphatic chain of the cellosolve increases. The results are discussed on the basis of molecular interactions between the components of the mixtures

Excess volumes and ultrasonic velocities of some amide +water systems at 298.15 K

1083-1087Excess volumes (VE) and isentropic compressibilities (Ks) have been determined at 298.15 K for the systems water + N-methylformamide, + N,N-dimethylformamide, + N-methyl-2-pyrrolidinone and + N,N-dirnethylacetamide. Excess volumes have been measured directly by means of a successive-dilution dilatometer and isentropic compressibilities have been computed from experimentally determined densities and velocities of sound. The speed of sound u has been obtained at 4 MHz in the whole composition range at 298.15K, using sing-around technique. Excess volumes and deviation in isentropic compressibility are all negative over the whole composition range. The values of both VE and Ks have been discussed in terms of intermolecular interactions between the mixing component of the binary mixture

Excess molar volumes of binary mixed solvents containing tetraethylene glycol and benzene, toluene, acetone and acetonitrile at 308.15 K

591-593Excess molar volumes of binary mixed solvents containing tetraethylene glycol and benzene, toluene, acetone and acetonitrile have been measured as a function of composition at 308.15K. The measurements have been carried out with a continuous-dilution dilatometer. The excess volumes are all negative over the entire range of composition. The results are discussed in terms of the interaction between components. The Flory model has been used to calculate the excess volumes, and are compared with experimental data for the four mixtures

Excess molar volumes and viscosities of the binary mixtures of ethylene glycol monoisopropyl ether with water at 298.15, 308.15 and 318.15K

421-424Excess molar volumes (VEm) and viscosities (η) have been measured for ethylene glycol monoisopropyl ether + water from 298.15 to 318.15 K at 10 K intervals. The excess volumes are negative while viscosities are positive over the entire composition range for the system studied. and temperature has no appreciable influence on excess volumes. The observed negative VEm values are compared with the available published results at 298.15 K. Densities (ρ) and deviations in viscosity (Δη)) of the mixtures have been calculated from the results. The deviations in viscosity values are positive over the entire range of mole fractions and temperatures. The results of excess molar volume and deviations in viscosity are fitted to the Redlich-Kister relation to estimate the adjustable parameters and standard deviations

Viscosities for binary liquid mixtures of <i>n</i>-alkoxyethanols with water at 298.15K

137-140Viscosities at 298.15 K for three alkoxyethanol+water mixtures have been measured over the whole mole fraction range by using an Ubbelohde viscometer . The alkoxyethanol was 2-(2-methoxyethoxy)ethanol or 2-(2- ethoxyethoxy)ethanol or 2-(2-butoxyethoxy)ethanol. From the experimental data, excess logarithmic viscosities (In ηE) and excess energies of activation for viscous flow (G*E) have been calculated. The excess functions are positive over the entire range of composition for all the systems studied. Also the values of parameter d12 have been calculated from the relation ln ηm = x1ln η1 + x2In η2 + x1x2d12, where η1 and η12 refer to the dynamic viscosities of the two pure liquids 1 and 2 whose mole fractions in the mixture are x1 and x2 respectively. The results for In ηE, G*E and d12 are discussed in terms of interactions of water with an ampbipbilic molecule