1,721,237 research outputs found
A tabu search method guided by a shifting bottleneck for a job shop scheduling
No full textA computationally effective heuristic method for solving the minimum makespan problem of job shop scheduling is presented. The proposed local search method is based on a tabu search technique and on the shifting bottleneck procedure used to generate the initial solution and to refine the next-current solutions. Computational experiments on a standard set of problem instances show that, in several cases, our approach, in a reasonable amount of computer time, yields better results than the other heuristic procedures discussed in the literature
E. Merelli, F. Pezzella. A tabu search method guided by a shifting bottleneck for a job shop scheduling. European Journal of Operational Research, volume 120, pagine 297-310, 2000
No full textA computationally effective heuristic method for solving the minimum makespan problem of job shop scheduling is presented. The proposed local search method is based on a tabu search technique and on the shifting bottleneck procedure used to generate the initial solution and to refine the next-current solutions. Computational experiments on a standard set of problem instances show that, in several cases, our approach, in a reasonable amount of computer time, yields better results than the other heuristic procedures discussed in the literature
Jacobi sigma models
No full textWe introduce a two-dimensional sigma model associated with a Jacobi manifold. The model is a generalisation of a Poisson sigma model providing a topological open string theory. In the Hamiltonian approach first class constraints are derived, which generate gauge invariance of the model under diffeomorphisms. The reduced phase space is finite-dimensional. By introducing a metric tensor on the target, a non-topological sigma model is obtained, yielding a Polyakov action with metric and B-field, whose target space is a Jacobi manifold
The anti-vegf(R) drug discovery legacy: Improving attrition rates by breaking the vicious cycle of angiogenesis in cancer
Full text linkResistance to anti-vascular endothelial growth factor (VEGF) molecules causes lack of response and disease recurrence. Acquired resistance develops as a result of genetic/epigenetic changes conferring to the cancer cells a drug resistant phenotype. In addition to tumor cells, tumor endothelial cells also undergo epigenetic modifications involved in resistance to anti-angiogenic therapies. The association of multiple anti-angiogenic molecules or a combination of anti-angiogenic drugs with other treatment regimens have been indicated as alternative therapeutic strategies to overcome resistance to anti-angiogenic therapies. Alternative mechanisms of tumor vasculature, including intussusceptive microvascular growth (IMG), vasculogenic mimicry, and vascular co-option, are involved in resistance to anti-angiogenic therapies. The crosstalk between angiogenesis and immune cells explains the efficacy of combining anti-angiogenic drugs with immune check-point inhibitors. Collectively, in order to increase clinical benefits and overcome resistance to anti-angiogenesis therapies, pan-omics profiling is key
An Adaptive Genetic Algorithm for Large-Size Open Stack Problems
No full textThe problem of minimising the maximum number of open stacks arises in many contexts (production planning, cutting environments, very-large-scale-integration circuit design, etc.) and consists of finding a sequence of tasks (products, cutting patterns, circuit gates, etc.) that determines an efficient utilisation of resources (stacks). We propose a genetic approach that combines classical genetic operators (selection, order crossover and pairwise interchange mutation) with an adaptive search strategy, where intensification and diversification phases are obtained by neighbourhood search and by a composite and dynamic fitness function that suitably modifies the search landscape. Computational tests on random and real-world benchmarks show that the proposed approach is competitive with the state of the art for large-size problems, providing better results for some classes of instances
On off-shell bosonic string amplitudes
No full textWe give a simple prescription for computing, in the framework of the bosonic string theory, off-shell one-loop amplitudes with any number of external massless particles, for both the open and closed strings. We discuss their properties and, in particular, for the two-string one-loop amplitudes, we show their transversality
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