International Journal of Modeling, Simulation, and Scientific Computing

We describe how to develop a suite of models in the MS4 Modeling Environment (MS4 Me). The approach employs the operation of merging of System Entity Structures supported by the environment. After construction, the suite of models can be hosted on Model Store, the cloud-based repository of models provided by MS4 systems as a basis for further collaborative model development. A suite of models, relating to Health Care is used as an example. In this paper, we review basic concepts of the SES needed to support of suites of simulation models. We then consider the concept of multiple aspects that provides more advanced capabilities to construct and manipulate suites of models. With this background, we go on to discuss a methodology for developing suites of simulation models and cloud-based technology for storing and sharing such models in a marketplace of models. Finally, we discuss future research and developments needed to bring the marketplace into common use by modeling and simulation practitioners.

Thin cylindrical shell structures have wide variety of applications due to their favorable stiffness-to-mass ratio and under axial compressive loading, these shell structures fail by their buckling instability. Hence, their load carrying capacity is decided by its buckling strength which in turn predominantly depends on the geometrical imperfections present on the shell structure. The main aim of the present study is to determine the more influential geometrical parameter out of two geometrical imperfection parameters namely, "the extent of imperfection present over a surface area" and its "amplitude". To account for these geometrical parameters simultaneously, the imperfection pattern is assumed as a dent having the shape of extent of surface area as a nearly square. The side length of extent of surface area can be considered as proportional to extent of imperfection present over an area and the dent depth can be considered as proportional to amplitude of imperfections. For the present numerical study, FE models of thin short carbon steel perfect cylindrical shells with different sizes of dent are generated at 1/3rd and half the height of cylindrical shells and analyzed using ANSYS nonlinear FE buckling analysis.

Climate variability and its changes are issues of broader global concern. This study addresses the annual air temperature movement evaluation and forecasting based on principal component analysis (PCA). An Eigen-temperature model for describing the annual air temperature movement by employing PCA is introduced. Subspace for evaluation is generated by selecting principal orthogonal eigenvectors of covariance matrix of temperature data. The principal eigenvectors are called "Eigen-temperatures", since they are eigenvectors and each temperature movement is described by them. Each temperature movement is projected onto the subspace of eigenspace, and described by a linear combination of the Eigen-temperatures. Then, a forecast method for the temperature movement by employing the Eigen-temperatures is proposed. Forecast is implemented with polynomial curve fitting algorithm to estimate subsequent representation weights for the subsequent temperature movement with respect to the "Eigen-temperatures" generated by its previous temperature movements. The proposed Eigen-temperature model is applied to evaluation and forecasting for annual temperature movement at Tongchuan observation station of China from 1962 to 1971 and from 1994 to 2002. Experimental results agreeing well with actual observation values show workability of the proposed. Result analysis indicates its effectiveness that the proposed Eigen-temperature model is outperforming the classical AR model and the BP-ANN on the forecast tasks.

A simulation method for investigating the vibration behavior of hoisting rope with time-varying length is improved. By previously creating markers in the MSC.ADAMS software package, the parametric model of the rope wound along helix is established based on the concentrated-mass theory with multi-degree of freedom (multi-DOF). A novel driving strategy, cooperating fixed joints with angle sensors under the control of driving script, is proposed to substitute conventional contact force. Researching on the hoisting rope in the sinking winch mechanism, an equivalent discretization model is obtained with complicated boundary conditions considered. The differential equations of motion of the hoisting system are formulated employing Lagrange's equation and numerically solved using Runge–Kutta method. The simulation indicates that the horizontal swing is decreased in principle and the simulation with 800 discrete ropes is not performed more than 61 min. Therefore, this feasible strategy could not only guarantee the accuracy but also promote simulation efficiency and stability. The motion curves exported from ADAMS simulation coincide with one in numerical simulation, which validates both the numerical model and the driving strategy.

All over the world, tuberculosis is a public health problem in prisons due to the fact that many inmates come from communities at high risk of tuberculosis, to their living conditions in prisons and to the insufficiencies of prisons health services. In this paper, Wells–Riley's equation for modeling airborne infection within indoor environment is incorporated on a simple tuberculosis model, to investigate the effect of prison environment on the transmission dynamics of tuberculosis. At best the study suggests that a prison cell of volume 195 m³ with 40 adult inmates comprising of 90% susceptibles and 10% infectives, requires a ventilation rate of 8 AC/h to maintain the reproductive number less than unity. However, if the population doubles then the ventilation required to maintain the reproductive number less than unity becomes 26 AC/h which is three times more than the actual ventilation rate required for a 100% full.

The one-dimensional Navier–Stokes equations are used to derive analytical expressions for the relation between pressure and volumetric flow rate in capillaries of five different converging-diverging axisymmetric geometries for Newtonian fluids. The results are compared to previously derived expressions for the same geometries using the lubrication approximation. The results of the one-dimensional Navier–Stokes are identical to those obtained from the lubrication approximation within a nondimensional numerical factor. The derived flow expressions have also been validated by comparison to numerical solutions obtained from discretization with numerical integration. Moreover, they have been certified by testing the convergence of solutions as the converging-diverging geometries approach the limiting straight geometry.

The aim of this work is to analyze the role of the impressed sources in determining the well or ill-posedness of time harmonic electromagnetic boundary value problems involving isotropic effective media. It is shown, in particular, that, even if all interfaces are regular, the class of ill-posed problems can be very large in the presence of general square-integrable impressed sources. However, when a simple and realistic constraint is enforced on these sources, requiring that the support of the sources does not include any interface between a traditional medium and a metamaterial, among the problems here considered just those involving an interface between complementary materials remain ill-posed. These considerations have a very significant impact also on the approximability of the solution of well-posed problems since the numerical noise can introduce small fictitious sources even where the sources to be simulated are not present. These effects on finite element simulators are fully analyzed. Finally, we propose an algorithm that allows to obtain much better approximations of the solutions of the most critical well-posed problems.

The incompressible miscible displacement problem in porous media is modeled by a coupled system of two nonlinear partial differential equations, the pressure–velocity equation and the concentration equation. In this paper, we present a mixed finite volume element method (FVEM) for the approximation of the pressure–velocity equation and a standard FVEM for the concentration equation. A priori error estimates in L^∞(L²) are derived for velocity, pressure and concentration. Numerical results are presented to substantiate the validity of the theoretical results.