We determine the stationary distribution of a one-sided Markov-Modulated Brownian Motion (MMBM) of which the behaviour is modified during the intervals between a visit to level zero and the next visit to a fixed positive level b. We use the semi-regenerative structure of the process, and we also use the fluid approximation for MMBMs introduced by Latouche and Nguyen in 2015. Finally, we show how the expressions can be simplified in some interesting special cases and we conclude by providing some numerical illustrations. 相似文献
We consider the real-time scheduling of full truckload transportation orders with time windows that arrive during schedule execution. Because a fast scheduling method is required, look-ahead heuristics are traditionally used to solve these kinds of problems. As an alternative, we introduce an agent-based approach where intelligent vehicle agents schedule their own routes. They interact with job agents, who strive for minimum transportation costs, using a Vickrey auction for each incoming order. This approach offers several advantages: it is fast, requires relatively little information and facilitates easy schedule adjustments in reaction to information updates. We compare the agent-based approach to more traditional hierarchical heuristics in an extensive simulation experiment. We find that a properly designed multi-agent approach performs as good as or even better than traditional methods. Particularly, the multi-agent approach yields less empty miles and a more stable service level. 相似文献
We have investigated the heteroepitaxy of indium nitride (InN) directly grown on nitridated sapphire substrates having different orientations. Growths were performed on C, A, M and R‐plane oriented sapphire in order to analyse the substrate orientation effect on the structural, optical and electronic properties of as‐grown InN. Atomic force microscopy imaging on the InN epilayers revealed different surface morphologies with crystallites well organized along a crystalline orientation of the layer. We have studied the structural anisotropy observed in these layers analysing high‐resolution X‐ray diffraction rocking curve experiments as a function of the in‐plane beam orientation. A‐plane oriented InN grown on R‐plane sapphire substrate shows a polarized photoluminescence anisotropy, with an anisotropy percentage of about 33%. 相似文献
Doped layers made of nanostructured silicon phases embedded in a silicon oxide matrix were implemented in thin film silicon solar cells. Their combination with optimized deposition processes for the silicon intrinsic layers is shown to allow for an increased resilience of the cell design to the substrate texture, with high electrical properties conserved on rough substrates. The presented optimizations thus permit turning the efficient light trapping provided by highly textured front electrodes into increased cell efficiencies, as reported for single junction cells and for amorphous silicon (a‐Si)/microcrystalline silicon tandem cells. Initial and stabilized efficiencies of 12.7 and 11.3%, respectively, are reported for such tandem configuration implementing a 1.1 µm thick microcrystalline silicon bottom cell.
A mild, practical, and simple procedure for peptide‐bond formation is reported. Instead of activation of the carboxylic acid functionality, the reaction involves an unprecedented use of activated α‐aminoesters. The method provides a straightforward entry to dipeptides and was effective when a sensitive cysteine residue was used, as no epimerization was detected in this case. The applicability of this method to iterative peptide synthesis was illustrated by the synthesis of a model tetrapeptide in the challenging reverse N→C direction. 相似文献
