Knowledge sharing is an activity through which knowledge, namely, information, skills, or expertise, is exchanged between people, friends, families, communities or organizations. Online knowledge sharing activities are flourishing with the advent of social media and digital life. However, despite of the importance of the online knowledge sharing methods and mechanisms, there is not any comprehensive and systematic study about studying and analyzing its important techniques. Therefore, the main aim of this paper, the comprehensive, detailed, and systematic study, and survey of the state-of-the-art knowledge sharing mechanisms in an online environments is provided. Also, this paper presents a systematic literature review (SLR) on the online knowledge sharing literatures up to end of 2015. We identified 348 papers, which are reduced to 251 primary studies through our paper selection process. Also, the broad overview of the literature provides insights into potential areas for further research. By providing state-of-the-art information, this survey will directly support academics and practicing professionals in their understanding of developments in online knowledge sharing mechanisms and techniques. 相似文献
Over time, architectural ornaments have had a variety of forms that are created from a combination of different types of materials and factors. Brick decorations are one such example, a type of ornament that is often formed on the exterior façade of buildings. Investigating covert rules and brick bonds geometry can reveal a part of the ancient architectural secrets and ways used to reduce the ravages upon new brick façades. Shaped bricks in traditional Iranian architecture directly affect the placement, size and brick arrangement rules. This article is the first attempt to study the effects of geometry and the principal rules of arrangement that help to shape the formation of brick façades specifically, as well as analysing the samples of brick façades taken from monuments, field recordings and discussion with the workmen themselves. The analysis has revealed that permanent rules govern the bonding of brick façades, along with the size and dimensions of the brick effects, which shape the final look of the decoration. 相似文献
High and low stremflow values forecasting is of great importance in field of water resources in order to mitigate the impacts of flood and drought. Most of water resources models deal with the problem of not being flexible for modeling maximum and minimum flows. To overcome that shortcoming, a combination of artificial neural network (ANN) models is developed in this study for monthly streamflow forecasting. A probabilistic neural network (PNN) is used to classify each of the input-output patterns and afterward, the classified data are forecasted using a modified multi-layer perceptron (MMLP). In addition, the performance of the MLP and generalized regression neural network (GRNN) in streamflow forecasting are investigated and compared to the proposed method. The findings indicate that the R2 associated with the suggested model is 46 and 80% higher compared to MLP and GRNN models, respectively. 相似文献
The seismic liquefaction has been observed in gravelly soils, in addition to sandy soils. Despite sandy soils, there is still a shortage of an extended case history database for developing empirical, semi-empirical, and probabilistic models to predict this phenomenon in gravelly soils. This study examines the documentations of several case histories of gravelly soil liquefaction all around the world to create a database, and then to develop probabilistic models to consider uncertainties of the models as well as the parameters for evaluating gravelly soil liquefaction triggering caused by earthquakes. The logistic regression and Bayesian mapping function, both of which are based on the maximizing likelihood estimation, were applied to present classifier curves to predict the occurrence of liquefaction. Additionally, a sensitivity analysis on the bias sampling weighting factor was performed to assess its effect on the model’s prediction accuracy. The results point to the effect of extended database and sampling bias on the developed models. Meanwhile, this study highlights the importance of developing probabilistic models rather than deterministic ones to consider uncertainties.
1% oxygen is incorporated into both CdS and CdTe layers through RF sputtering of CdS/CdTe thin film solar cells. The optical and electrical parameters of the oxygenated and O2-free devices are compared after CdCl2 treatment and annealing in ambient Ar and/or air. The effects of ambient annealing on the electrical and optical properties of the films are investigated using current-voltage characterization, field emission scanning electron microscopy, X-ray diffraction, and optical transmission spectroscopy. The 1% oxygen content can slightly increase the grain size while the crystallinity does not change. Annealing in ambient Ar can increase the transmission rate of the oxygenated devices. 相似文献
The development of an egg-shell like structure in skim milk powder has been investigated in a stirred fluidized-bed dryer at various temperatures and humidities. The developed particles have crystalline surfaces and amorphous cores. The SEM analysis shows a thin layer of lactose crystals (at the nano-scale) that is formed on the surface of the powder while the XRD analysis shows that the particle cores are still amorphous (egg-shell form), so the surface properties have improved while the bulk desirable properties (of good solubility) have been retained. The resulting powders show better flowability and stability and less cake formation during storage by retaining good rehydration and dissolution times. The nano-coating of milk powders by crystalline lactose from the powder itself and the improvement in stability and flowability could be a worthwhile solution for dairy industries. 相似文献
The objective of this work is to model the sensitivity of high cycle fatigue resistance of secondary hardening martensitic gear steels to variability in extrinsic inhomogeneities such as primary inclusions, and pores, coupled with intrinsic microstructure variability. A simplified approach is presented to quantify the variability in the driving force for fatigue crack formation in the matrix at non-metallic inclusions and pores in lath martensitic gear steels using a three-dimensional crystal plasticity constitutive model. The utility of a simulation-based strategy for exploring sensitivity of minimum fatigue lifetime (low probability of failure) to microstructure lies in its inherent capability to consider parametric simulations of hundreds of inclusions and microstructures in contrast to limited numbers of physical experiments. Experiments are used to calibrate the polycrystalline cyclic stress–strain response and mean (50% probability) fatigue crack formation life. Several remote loading conditions are considered in the high cycle fatigue (HCF) regime relevant to typical gear applications. Idealized inhomogenieties (spherical) in the form of hard (Al2O3), soft inclusions (La2O2S), and pores are systematically investigated in this parametric computational study. Relations between remote loading conditions and local plasticity are discussed as a function of stress amplitude and microstructure. The maximum plastic shear strain range is used in the modified form of Fatemi–Socie parameter evaluated at the grain scale as a measure of the driving force for fatigue crack formation (nucleation and early growth to lengths on the order of several times the average grain size). Multiple realizations of the polycrystal microstructure are considered to obtain a statistical distribution of this fatigue indicator parameter (FIP). The results are used to construct an extreme value Gumbel distribution of the FIPs for the selected microstructures. Subsequently, a computational micromechanics based minimum life estimate that corresponds to 1% fatigue crack formation probability is calculated. 相似文献
Nanoparticulated TiO(2) fibers as one-dimensional long structures were introduced into TiO(2) P25 nanoparticle films using coelectrophoretic deposition. This prevented the usual crack formation occurring in wet coatings, and resulted in less porosity and higher roughness factor of the films that provided more favorable conditions for electron transport. The films used as the photoanode of a dye solar cell (DSC) produced 65% higher photovoltaic efficiency. TiO(2) fibers can be excellent binders in single-step, organic-free electrophoretic deposition of TiO(2) for DSC photoanode. 相似文献