This paper develops a Bayesian analysis in the context of record statistics values from the two-parameter Weibull distribution. The ML and the Bayes estimates based on record values are derived for the two unknown parameters and some survival time parameters e.g. reliability and hazard functions. The Bayes estimates are obtained based on a conjugate prior for the scale parameter and a discrete prior for the shape parameter of this model. This is done with respect to both symmetric loss function (squared error loss), and asymmetric loss function (linear-exponential (LINEX)) loss function. The maximum likelihood and the different Bayes estimates are compared via a Monte Carlo simulation study. A practical example consisting of real record values using the data from an accelerated test on insulating fluid reported by Nelson was used for illustration and comparison. Finally, Bayesian predictive density function, which is necessary to obtain bounds for predictive interval of future record is derived and discussed using a numerical example. The results may be of interest in a situation where only record values are stored. 相似文献
We address the problem of garbage collection in a single-failure fault-tolerant home-based lazy release consistency (HLRC) distributed shared-memory (DSM) system based on independent checkpointing and logging. Our solution uses laziness in garbage collection and exploits consistency constraints of the HLRC memory model for low overhead and scalability. We prove safe bounds on the state that must be retained in the system to guarantee correct recovery after a failure. We devise two algorithms for garbage collection of checkpoints and logs, checkpoint garbage collection (CGC), and lazy log trimming (LLT). The proposed approach targets large-scale distributed shared-memory computing on local-area clusters of computers. The challenge lies in controlling the size of the logs and the number of checkpoints without global synchronization while tolerating transient disruptions in communication. Evaluation results for real applications show that it effectively bounds the number of past checkpoints to be retained and the size of the logs in stable storage 相似文献
This study presents an integrated approach for the identification of groundwater occurrences in shallow fracture zone (SFZ) aquifers using remote-sensing, geological, and geophysical data. The Central Eastern Desert of Egypt was selected as a test site for the present study. The distribution of major faults and shear zones was extracted from a fusion image generated by injecting high-spatial resolution phased array L-band synthetic aperture radar (PALSAR) images into Landsat Enhanced Thematic Mapper images. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) digital elevation model was processed to extract the drainage systems, slope, and topographic wetness index (TWI). The multidate PALSAR imagery acquired during rainy and dry seasons was used to estimate the relative soil moisture content. The lithology, fractures, drainage density, slope, TWI, and soil moisture content were used as thematic layers for groundwater occurrence in the SFZ aquifers. A GIS model of groundwater potential was developed by selecting the most probable locations for groundwater in each layer. The results indicate that the spatial distribution of the existing water wells is in agreement with the model where all wells fall in the regions of high groundwater potential zones. A geophysical survey was conducted using ground penetrating radar (GPR), indicating that the high groundwater potential zones are promising for drilling shallow wells. The adopted approach can be used as a cost-effective tool for groundwater exploration in the SFZ aquifers in the study area and in areas of similar geologic and hydrogeologic settings elsewhere. 相似文献
Knowledge and Information Systems - Generalized spherical fuzzy number (GSFN) is an extension of spherical fuzzy number (SFN) which deals the uncertainties involved in the real-life problems in... 相似文献
This is the third in a series of papers in which the thermal degradation of ethylene-vinyl acetate (EVA) and ethylene-butyl acrylate (EBA) copolymers are compared. The EBA samples contained 0.8, 1.6, and 5.4 mol % butyl acrylate (BA), respectively, and the EVA samples 1.2 and 6.7 mol % vinyl acetate (VA). The samples were heated in nitrogen in a tubular oven at 285–390°C, for 6–120 min. The molecular weight distribution (MWD), long chain branching, and gel content were analyzed with size exclusion chromatography (SEC). The columns were connected to refractive index, viscometric, and light scattering detectors. EVA gave a pronounced molecular enlargement at all degradation temperatures. In EVA-6.7, gel was formed at all degradation levels, whereas the low content sample, EVA-1.2, did not form any visible amount of gel. The strong tendency to molecular enlargement is due to allyl radicals formed after thermal deacetylation and the formation of internal double bonds. These macroradicals will combine or, less frequently, add to double bonds. The EBA copolymers show a more polyethylenelike degradation behavior. At 285°C molecular enlargement dominates, but already at 333°C a net reduction in molecular size is observed. At high temperatures, ester pyrolysis of the BA groups give carboxylic groups and anhydrides. Alkaline treatment will not give any appreciable change in MWD, showing that the anhydride formation is mainly intramolecular. The chain scission increases with the BA content. This is probably due to β-cleavage of tertiary macroradicals formed in the chain at the acrylate or carboxylic side groups. 相似文献
This study proposes a novel design to systematically optimize the parameters for the adaptive neuro-fuzzy inference system (ANFIS) model using stochastic fractal search (SFS) algorithm. To affirm the efficiency of the proposed SFS-ANFIS model, the predicting results were compared with ANFIS and three hybrid methodologies based on ANFIS combined with genetic algorithm (GA), differential evolution (DE), and particle swarm optimization (PSO). Accurate prediction of uniaxial compressive strength (UCS) is of great significance for all geotechnical projects such as tunnels and dams. Hence, this study proposes the use of SFS-ANFIS, GA-ANFIS, DE-ANFIS, PSO-ANFIS, and ANFIS models to predict UCS. In this regard, the fresh water tunnel of Pahang–Selangor located in Malaysia was considered and the requirement data samples were collected. Different statistical metrics such as coefficient of determination (R2) and mean absolute error were used to evaluate the models. Referring to the efficiency results of SFS-ANFIS, it can be found that the SFS-ANFIS (with the R2 of 0.981) has higher ability than PSO-ANFIS, DE-ANFIS, GA-ANFIS, and ANFIS models in predicting the UCS.
This study proposes Chebyshev wavelet collocation method for partial differential equation and applies to solve magnetohydrodynamic (MHD) flow equations in a rectangular duct in the presence of transverse external oblique magnetic field. Approximate solutions of velocity and induced magnetic field are obtained for steady‐state, fully developed, incompressible flow for a conducting fluid inside the duct. Numerical results of the MHD flow problem show that the accuracy of proposed method is quite good even in the case of a small number of grid points. The results for velocity and induced magnetic field are visualized in terms of graphics for values of Hartmann number Ha ≤ 1000.
The chemical desulfurization of two high-sulfur Turkish lignites was investigated using a mixture of hydrogen peroxide in acetic acid. Sulfur removal was measured with respect to particle size, reaction time, reaction temperature and ultrasonic irradiation. In general, all inorganic sulfur and some organic sulfur were removed from these coals under mild conditions. Cayirhan lignite seemed more reactive towards peroxyacedic acid at slightly higher temperatures and longer reaction times, but under these conditions, solubility was high and yields of solid products declined. Reaction time and reaction temperature slightly changed the level of sulfur removal from Gediz lignite. The level of desulfurization was largely independent of the particle size for Gediz lignite, while sulfur removal from Cayirhan lignite seemed dependent of the particle size reaction temperature and reaction time. 相似文献
This paper describes the potential of the development of a seawater desalination system that combines the technologies of reverse osmosis (RO) and photovoltaic (PV) to deliver 100 m3/day of sweet water. Silicon cells are chosen for the PV array and the polyamide thin-film composite seawater Filmtec membranes are selected for the RO system. The software ROSA is adopted to study the influences of the feed pressure on the performance of the system. It is found that as the feed pressure increases, the specific energy of the plant decreases but the percentage of recovery increases. 相似文献