Set Of Combination Rules Research Articles

Combination Rules and Accurate van der Waals Force Field for Gas Uptakes in Porous Materials.

Morse function is suggested to be more suitable for studying the gas adsorption in porous frameworks than the Lennard-Jones and exponential-6 forms. However, there have not been some widely used Morse-based van der Waals force fields (vdW FFs) because of complicated parameterization. Combining rules is usually suggested to reduce the parameterization by calculating the unlike-pair parameters from the information of the like pair. A new set of combination rules (DRS) for Morse-based FF has been proposed in our prior work and shown good performance in the simulation of CH4 adsorption isotherms in covalent organic frameworks. Inspired by our prior work, we developed an accurate van der Waals FF using high-level ab initio calculations with the DRS combination rules. The validation was conducted by comparing the simulated gas uptakes with the experimental values for various known porous materials. The agreement between simulations and experiments is very good, showing the potential application of the FF and the DRS combination rules.

A correspondence between belief function combination and knowledge base merging

In intelligent systems, belief function is a common approach to modelling uncertain and imperfect information obtained constantly while knowledge bases are used to encapsulate multiple static information items. In the literature, many different approaches have been proposed for combining belief functions (resp. merging knowledge bases) when there are multiple belief functions (resp. knowledge bases) generated from different sources depicting the same issue of interest. However, the connection between belief function combination and knowledge base merging is not adequately explored. In this paper, we aim to study the correspondence between the two lines of research. By introducing a numerical characteristic function for each knowledge base, we show that there is one to one correspondence between a set of combination rules of belief functions and merging methods of weighted knowledge bases.

Combination Rules for Morse-Based van der Waals Force Fields.

In traditional force fields (FFs), van der Waals interactions have been usually described by the Lennard-Jones potentials. Conventional combination rules for the parameters of van der Waals (VDW) cross-termed interactions were developed for the Lennard-Jones based FFs. Here, we report that the Morse potentials were a better function to describe VDW interactions calculated by highly precise quantum mechanics methods. A new set of combination rules was developed for Morse-based FFs, in which VDW interactions were described by Morse potentials. The new set of combination rules has been verified by comparing the second virial coefficients of 11 noble gas mixtures. For all of the mixed binaries considered in this work, the combination rules work very well and are superior to all three other existing sets of combination rules reported in the literature. We further used the Morse-based FF by using the combination rules to simulate the adsorption isotherms of CH4 at 298 K in four covalent-organic frameworks (COFs). The overall agreement is great, which supports the further applications of this new set of combination rules in more realistic simulation systems.

Roof model recommendation for complex buildings based on combination rules and symmetry features in footprints

ABSTRACTCurrently, very few roof shape information for complex buildings is available on OSM. Moreover, additional data requirements (e.g. 3D point clouds) limit the applicability of many roof reconstruction approaches. To mitigate this issue, we propose an approach to roof shape recommendations for complex buildings by exploring the inherited characteristics of building footprints: the disclosure of rectangles combinations in a partition of footprints and the symmetrical features of footprints. First, it decomposes a complex footprint into rectangles by using an advanced minimal non-overlapping cover algorithm. Second, a graph-based symmetry detection algorithm is proposed to identify all the symmetrical sub-clusters in partitions. Then, a set of selection rules are defined to rank partitions, and the best ones are chosen for roof shape recommendation. Finally, a set of combination rules and a symmetry rule are defined. It enables to evaluate the probability of a footprint being a certain combination of roof shapes. Experimental results show the growth of the probability of correctly recommending roof shapes for single rectangles and buildings from a prior probability of 17–45% and from a prior probability of 0.29–14.3%, removing 60% and 93% of the incorrect roof shape options, respectively.

Combining partially independent belief functions

The theory of belief functions manages uncertainty and also proposes a set of combination rules to aggregate opinions of several sources. Some combination rules mix evidential information where sources are independent; other rules are suited to combine evidential information held by dependent sources. In this paper we have two main contributions: First we suggest a method to quantify sources' degree of independence that may guide the choice of the more appropriate set of combination rules. Second, we propose a new combination rule that takes consideration of sources' degree of independence. The proposed method is illustrated on generated mass functions.

A Framework to Build Process Theories of Anticipatory Information and Communication Technology (ICT) Standardizing

Standards have become critical to information and communication technologies (ICTs) as they become complex and pervasive. We propose a process theory framework to explain anticipatory standardizing outcomes post hoc when the standardizing process is viewed as networks of events. Anticipatory standards define future capabilities for ICT ex ante in contrast to ex post standardizing existing practices or capabilities through de facto standardization in the market. The theoretical framework offers the following: a) a lexicon in the form of the ontology and typology of standardizing events; b) a grammar, or a set of combination rules, for standardizing events to build process representations; c) an analysis and appreciation of contexts in which standardizing unfolds; and d) logic yielding theoretical explanations of standardizing outcomes based on the analysis of process representations. We show how the framework can help analyze standardization data as networks of events as well as explain standardizing outcomes. We illustrate the plausibility of the approach by applying it to wireless standardization to explain standardizing outcomes.

Phase equilibria and thermodynamic properties of molecular fluids from perturbation theory

Abstract The thermodynamic perturbation theory developed in Part I of this work is applied to describe phase equilibria and thermodynamic excess properties of binary fluid mixtures. The theory is based on the spherically symmetric reference system represented by the Lennard-Jones pair interactions, whereas the isotropic and anisotropic interactions arising from two-body electrostatic induction dispersion and repulsion forces and from three-body induction and dispersion forces, are treated as perturbations. These calculations differ from the previous perturbation theories based on the equation of state for argon as the reference system in two major respects. First the reference mixture properties are computed more accurately using a reliable form of the perturbation theory of simple fluid mixtures. Second unlike potential parameters are estimated adequately using a recently proposed set of combination rules. Comparisons of theoretical results with experimental data for phase equilibria and thermodynamic excess properties are presented for some selected fluid mixtures, namely argon + krypton xenon + ethylene, carbon dioxide + ethane, and xenon + hydrogen bromide. These comparisons show a very good performance of the perturbation theory, which offers a significant improvement over a similar form of the perturbation theory based on the equation of state for argon as the reference mixture.

A Fuzzy Set Analysis of Skill, Rule and Knowledge-Based Workload

Using fuzzy measures of task difficulty the effect of combining different aspects of a task on the overall task workload was explored. A complete set of combination rules is provided, of the general form “if the skill-based component is slightly difficult, the rule-based moderately difficult, and the knowledge-based slightly difficult, then the task as a whole is moderately difficult.” Fuzzy linguistic variables provide an adequate systematic framework for such combined judgments.

The application of the Morse potential function in ordered Cu3Au and Au3Cu alloys

The Morse potential function has been applied to describe the harmonic properties of Cu3Au and Au3Cu alloys in the state of perfect order from first and second nearest neighbour considerations. The potential parameters for like and unlike atomic interactions have been determined in a consistent manner. In the case of unlike atomic interactions a set of combination rules has been used to determine the parameters. Utilizing these parameters the nearest neighbour distances, elastic constants, Debye temperatures and cohesive energies for the ordered Cu3Au and Au3Cu alloys have been calculated from the derived expressions. A fairly satisfactory agreement has been observed when compared with the available experimental values.

Viscosity of Binary Polar-Gas Mixtures

Viscosity of the binary polar-gas mixtures ammonia–diethyl ether and hydrogen sulfide–diethyl ether has been measured as a function of composition and temperature by a precision oscillating-disk method. The experimental results have been interpreted in terms of the Chapman–Enskog theory by using the 12–6–3 potential with a set of combination rules for polar–polar interaction. The viscosity data have been used to obtain the interdiffusion coefficients for these systems.

Properties of Gases and Gaseous Mixtures with a Morse Potential

Second virial coefficients, viscosity, thermal conductivity and diffusion coefficients of binary gas mixtures have been computed for the MORSE potential in conjunction with a set of combination rules for the unlike interactions. These calculated values are compared with the experimenta l values with a view to derive inferences regarding the adequacy of the recently proposed MORSE potential. On the basis of this detailed comparison of theory and experiment some specific and useful conclusions have been drawn which enable one to understand the relative footing of this potential in reference to the other two realistic potentials, viz. L-J (12-6) and exp-six.

Transport Properties of Polar-Gas Mixtures

A previously proposed model for the calculation of viscosity, diffusion, and thermal diffusion in dilute polar gases is extended to mixtures. A simple set of combination rules for the potential parameters is discussed. Available data limit the comparison of calculation and experiment to binary mixtures of a polar and a nonpolar gas. The agreement exhibits a success comparable to that obtained for models and combination rules involving only nonpolar gases. It is concluded that the present model and combination rules can be used to describe the transport properties of mixtures with a fair measure of success, and that any attempts to refine the combination rules should await more experimental results of high accuracy, especially results on thermal diffusion and diffusion.

Unlike Molecular Interactions and Properties of Gas Mixtures

Recently we have developed a set of semiempirical combination rules which may be utilized to calculate the intermolecular potentials for unlike pairs of molecules from the known potentials for like pairs on the modified Buckingham exp—six model. It is, therefore, necessary to see how far these combination rules can reproduce the transport properties of binary gaseous mixtures over large ranges of temperature and concentration. With this end in view various transport properties such as themal diffusion, interdiffusion, thermal conductivity, and viscosity have been calculated for a large number of binary mixtures and the computed values compared with the experimental data. It is found that the agreement between the theory and experiment is quite satisfactory. It is concluded that this set of combination rules can be used with success to predict the transport properties of gaseous mixtures within the limits of experimental error.