A simulation based digital twin approach to assessing the organization of response to emergency calls.

In emergency situations, timely contact with emergency medical communication centers (EMCCs) is critical for patient outcomes. Increasing call volumes and economic constraints are challenging many countries, necessitating organizational changes in EMCCs. This study uses a simulation-based digital twin approach, creating a virtual model of EMCC operations to assess the impact of different organizational scenarios on accessibility.

Effective media equivalent to an asymmetric multilayer and to a rough interface.

A computer fitting program is used to show that not only a symmetric but also an asymmetric multilayer, composed of a periodic structure with small thickness irregularity or with slightly rough interfaces, can be equivalent to an anisotropic single layer within a good approximation. It is also shown that an interface layer equivalent to a rough interface does not exist, in spite of the fact that such an assumption has widely been used.

Effective medium equivalent to a symmetric multilayer at oblique incidence.

It is shown that a multilayer with repeated symmetric unit structure is equivalent to a homogeneous and optically biaxial medium for obliquely incident light, the three principal axes being normal to the plane of incidence, normal to the film plane, and normal to the other two. Unit thickness dependence and incident angle dependence of the dielectric tensor and the effective thickness are calculated using exact formulas. It is found that, at small unit structure thickness, the equivalent medium is almost uniaxial, the optical axis being normal to the film, and the effective thickness is very close to the mechanical one.