Families of nested completely regular codes and distance-regular graphs

In this paper infinite families of linear binary nested completely regular codes are constructed. They have covering radius $\rho$ equal to $3$ or $4$, and are $1/2^i$-th parts, for $i\in\{1,\ldots,u\}$ of binary (respectively, extended binary) Hamming codes of length $n=2^m-1$ (respectively, $2^m$), where $m=2u$. In the usual way, i.e., as coset graphs, infinite families of embedded distance-regular coset graphs of diameter $D$ equal to $3$ or $4$ are constructed. In some cases, the constructed codes are also completely transitive codes and the corresponding coset graphs are distance-transitive

Extended Seismic Source Characterisation using Linear Programming Inversion in a Dual Formulation

A linear programming (LP) inversion method in a dual formulation was applied to reconstruct the kinematics of finite seismic ruptures. In a general setting, this approach can yield results from several data sets: strong ground motion, teleseismic waveforms or/and geodesic data (static deformation). The dual formulation involves the transformation of a normal solution space into an equivalent but reduced space: the dual space. The practical result of this transformation is a simpler inversion problem that is therefore faster to resolve, more stable and more robust. The developed algorithm includes a forward problem that calculates Green’s functions using a finite differences method with a 3D structure model. To evaluate the performance of this algorithm, we applied it to the reconstitution of a realistic slip distribution model from a data set synthesised using this model, i.e., the solution of the forward problem. Several other standard inversion approaches were applied to the same synthetic data for comparison

Optimized Multimode Interference Fiber Based Refractometer in A Reflective Interrogation Scheme

A fiber based refractometer in a reflective interrogation scheme is investigated and optimized. A thin gold film was deposited on the tip of a coreless fiber section, which is spliced with a single mode fiber. The coreless fiber is a multimode waveguide, and the observed effects are due to multimode interference. To investigate and optimize the structure, the multimode part of the sensor is built with 3 different lengths: 58 mm, 29 mm and 17 mm. We use a broadband light source ranging from 1475 nm to 1650 nm and we test the sensors with liquids of varying refractive indices, from 1.333 to 1.438. Our results show that for a fixed wavelength, the sensor sensitivity is independent of the multimode fiber length, but we observed a sensitivity increase of approximately 0.7 nm/RIU for a one-nanometer increase in wavelength