Atomistic spin dynamics simulations provide valuable information about the energy spectrum of magnetic materials in different phases, allowing one to identify instabilities and nature their excitations. However, time cost evaluating dynamical correlation function $S(\mathbf{q}, t)$ increases quadratically as number spins $N$, leading significant computational effort, making simulation large sys...

We investigate the following problem: Given two embeddings G1 and G2 of the same abstract graph G on an orientable surface S, decide whether G1 and G2 are isotopic; in other words, whether there exists a continuous family of embeddings between G1 and G2. We provide efficient algorithms to solve this problem in two models. In the first model, the input consists of the arrangement of G1 (resp., G...

Surface nano-crystallization techniques have been recently developed as one of the most effient ways to optimize materials’ structure, and therefore develop local global mechanical behavior increase strength without compromising ductility. In this work, we present a constitutive model incorporating grain refinement hardening simulate technique, specifically, surface attrition treatment. The com...

Grain growth and hardness variation occurring in high-temperature heat affected zone (HAZ) during the welding processes are two thermal dependant aspects of great interest for both academic industrial research activities. This paper presents an innovative finite element (FE) model capable to describe grain decrease that occur gas metal arc (GMAW) commercial AISI 441 steel. The FE software SFTC ...

Primary induction of photo-oxidative (phox)-ER stress in cancer cells evoked immunogenic apoptosis (IA) associated with pre-apoptotic emission of calreticulin and ATP, and protective antitumor immunity. This IA subroutine involved "core" functions (e.g., PERK/PI3K-based modulation of secretory trafficking) rather than "private" ones (caspase-8 and eIF2α-phosphorylation) engaged by other IA indu...

We present an algorithm for constructing an optimal slate of sponsored search advertisements which respects the ordering that is the outcome of a generalized second price auction, but which must also accommodate complicating factors such as overall budget constraints. The algorithm is easily fast enough to use on the fly for typical problem sizes, or as a subroutine in an overall optimization.

We study the problem of hierarchical clustering on planar graphs. We formulate this in terms of finding the closest ultrametric to a specified set of distances and solve it using an LP relaxation that leverages minimum cost perfect matching as a subroutine to efficiently explore the space of planar partitions. We apply our algorithm to the problem of hierarchical image segmentation.