Semantic operations of multiple soft sets under conflict

AbstractMolodtsov initiated the concept of soft set theory, which can be used as a generic mathematical tool for dealing with uncertainty. Description Logics (DLs) are a family of knowledge representation languages which can be used to represent the terminological knowledge of an application domain in a structured and formally well-understood way. Nowadays, properties and semantics of ontology constructs mainly are determined by DLs. In this paper we investigate semantic operations of multiple standard soft sets by using domain ontologies (i.e., DL intensional knowledge bases). Concretely, we give some semantic operations such as complement, restricted difference, extended union, restricted intersection, restricted union, extended intersection, AND, and OR for (multiple) standard soft sets from a semantic point of view. Especially, we also present an approach to deal with conflict from a semantic point of view when we define these semantic operations. Moreover, the basic properties and implementation methods of these semantic operations under conflict are also presented and discussed

A model to predict the thermodynamic stability of abiotic methane-hydrogen binary hydrates in a marine serpentinization environment

Abiotic methane (CH4) and hydrogen (H2), which are produced during marine serpentinization, provide abundant gas source for hydrate formation on ocean floor. However, previous models of CH4–H2 hydrate formation have generally focused on pure water environments and have not considered the effects of salinity. In this study, the van der Waals–Platteeuw model, which considered the effects of salinity on the chemical potentials of CH4, H2, and H2O, was applied in a marine serpentinization environment. The model uses an empirical formula and the Peng–Robinson equation of state to calculate the Langmuir constants and fugacity values, respectively, of CH4 and H2, and it uses the Pitzer model to calculate the activity coefficients of H2O in the CH4–H2–seawater system. The three-phase equilibrium temperature and pressure predicted by the model for CH4–H2 hydrates in pure water demonstrated good agreement with experimental data. The model was then used to predict the three-phase equilibrium temperature and pressure for CH4–H2 hydrates in a NaCl solutions, for which relevant experimental data are lacking. Thus, this study provides a theoretical basis for gas hydrate research and investigation in areas with marine serpentinization

Influence of water flow on gas hydrate accumulation at cold vents

A cold vent is an area where methane-rich fluid seepage occurs. This seepage may alter the local temperature, salinity, and subsequent accumulation of the gas hydrate. Using a kinetic gas hydrate formation model and in situ measurement of temperature, salinity and fluid flux at the southern summit of Hydrate Ridge, we simulate the gas hydrate accumulation at three distinct fluid sites: clam, bacterial mat, and gas discharge sites. At the clam sites (pore water flux 0.8 mol kg(-1)) by the formation of gas hydrate causing the base of the hydrate stability zone to move gradually from similar to 115 to similar to 70 meters below seafloor (mbsf). The gas hydrate saturation at the clam sites is relatively high. The water flux at the bacterial mat sites ranges from 100 to 2500 kg m(-2) yr(-1). The water flow suppresses the increase in salinity resulting in a salinity close to or slightly higher than that of seawater (< 0.65 mol kg(-1)). Heat advection by water flow increases temperature significantly, shifting the base of the hydrate stability zone to above 50 or even 3 mbsf. The gas hydrate saturation is relatively low at the bacterial mat site. At the gas discharge sites, the pore water flux could reach 10(10) kg m(-2) yr(-1), and the temperature could reach that of the source area in 9 min. There is no gas hydrate formation at the gas discharge sites. Our simulative analysis therefore reveals that a lower pore water flux would result in lower salinity, higher temperature, and a shallower base of the hydrate stability zone. This in turn induces a lower gas hydrate formation rate, lower hydrate saturation, and eventually less gas hydrate resources

An Accurate Model for Estimating H₂ Solubility in Pure Water and Aqueous NaCl Solutions

By employing a specific particle interaction theory and a high-precision equation of states for the liquid and vapor phases of H2, respectively, a new H2 solubility model in pure water and aqueous NaCl solutions is proposed in this study. The model established by fitting the experimental data of H2 solubility can be used to estimate H2 solubility in pure water at temperatures and pressures of 273.15–423.15 K and 0–1100 bar, respectively, and in salt solutions (NaCl concentration = 0–5 mol/kg) at temperatures and pressures of 273.15–373.15 K and 0–230 bar, respectively. By adopting the theory of liquid electrolyte solutions, the model can also be used to predict H2 solubility in seawater without fitting the experimental data of a seawater system. Within or close to experimental data uncertainty, the mean absolute percentage error between the model-predicted and experimentally obtained H2 solubilities was less than 1.14%

semantic operations of multiple soft sets under conflict

Molodtsov initiated the concept of soft set theory, which can be used as a generic mathematical tool for dealing with uncertainty. Description Logics (DLs) are a family of knowledge representation languages which can be used to represent the terminological knowledge of an application domain in a structured and formally well-understood way. Nowadays, properties and semantics of ontology constructs mainly are determined by DLs. In this paper we investigate semantic operations of multiple standard soft sets by using domain ontologies (i.e., DL intensional knowledge bases). Concretely, we give some semantic operations such as complement, restricted difference, extended union, restricted intersection, restricted union, extended intersection, AND, and OR for (multiple) standard soft sets from a semantic point of view. Especially, we also present an approach to deal with conflict from a semantic point of view when we define these semantic operations. Moreover, the basic properties and implementation methods of these semantic operations under conflict are also presented and discussed. &copy; 2011 Elsevier Ltd. All rights reserved

Numerical Analysis on Gas Production Efficiency from Hydrate Deposits by Thermal Stimulation: Application to the Shenhu Area, South China Sea

Gas hydrates have been attracted a great deal of attention because of their potential as an energy substitute and the climate implications. Drilling and sampling research on the hydrate deposit in the Shenhu Area on the northern continental slope of the Southern China Sea was a big breakthrough for hydrate investigation in China, but as a new potential energy source, how the gas can be effectively produced from hydrate deposits has become a hot research topic. Besides depressurization heat stimulation is regarded as another important means for producing hydrate-derived gas, however, the production efficiency and economic feasibility of producing gas by heat stimulation have not been clearly understood. In this paper, a simplified model for predicting gas production from hydrate deposits by heat stimulation is developed. The model ideally neglects the effects of heat convection and pressure regime in the sediments for simplicity. We compute the heat consumption efficiency and gas energy efficiency of gas production from hydrate deposits by heat stimulation, only considering effect of hydrate dissociation due to heat input. This model is for predicting the maximum production efficiency. By studying the hydrate reservoirs and significant parameters collected from drilling and sampling researches, we calculate the production potential of the Shenhu hydrate deposits and investigate the production efficiency and feasibility. Our research shows that the maximum amount of cumulative gas production at Shenhu is similar to 509 m(3) per meter in three years. The production potential is much lower than the industrial criterion for marine production. In our discussion the numerical simulations show that a practical potential of the gas production is merely 25 m(3)/m in 3 years and contribution of thermal stimulation is very small in joint-production schemes. We conclude that production cost is quite high and the economic value of producing gas from the hydrate through a vertical well is not attractive, even though the production by heat stimulation theoretically has a very high heat consumption rate and energy efficiency

An Accurate Model for Estimating H2 Solubility in Pure Water and Aqueous NaCl Solutions

By employing a specific particle interaction theory and a high-precision equation of states for the liquid and vapor phases of H2, respectively, a new H2 solubility model in pure water and aqueous NaCl solutions is proposed in this study. The model established by fitting the experimental data of H2 solubility can be used to estimate H2 solubility in pure water at temperatures and pressures of 273.15&ndash;423.15 K and 0&ndash;1100 bar, respectively, and in salt solutions (NaCl concentration = 0&ndash;5 mol/kg) at temperatures and pressures of 273.15&ndash;373.15 K and 0&ndash;230 bar, respectively. By adopting the theory of liquid electrolyte solutions, the model can also be used to predict H2 solubility in seawater without fitting the experimental data of a seawater system. Within or close to experimental data uncertainty, the mean absolute percentage error between the model-predicted and experimentally obtained H2 solubilities was less than 1.14%

An Improved LSTM Model for Behavior Recognition of Intelligent Vehicles

© 2013 IEEE. Long Short-Term Memory (LSTM) neural network has been widely used in many applications, but its application in classification of vehicle movement patterns is still limited. In this paper, LSTM is applied to the vehicle behavior recognition problem to identify the left turn, right turn and straight behavior of the vehicle at the intersection. On the basis of the traditional LSTM classification model, this paper transversely merges the input features and then inputs into a LSTM cell to get an improved model. The improved model can make full use of the input information and reduce unnecessary calculations, and the output of a single LSTM cell model can filter out interference information and retain important information, so it has better classification effect and faster training speed. The experimental results show that the proposed improved LSTM network classification model in this paper has a significant improvement in recognition accuracy and training speed compared with the improved model, the accuracy is increased by 1.6%, and the training time is reduced by 3.96 s. In addition, this paper also applies the improved model to regression problems, emotion classification and handwritten digit recognition and all of them have a good improvement effect, which improves the applicability and stability of LSTM in classification problems and provides a new way to deal with classification problems