The bottleneck in a production-inventory network is commonly taken to be the facility that most limits flow through the network and thus the most highly utilized facility. A further connotation of “bottleneck,” however, is the facility that most constrains system-wide performance or the facility at which additional resources would have the greatest impact. Adopting this broader sense of the ter...

We consider a multi-product and multi-component Assemble-to-Order (ATO) system where the external demand follows compound Poisson processes and component inventories are controlled by continuous-time batch ordering policies. The replenishment lead-times of components are stochastic, sequential and exogenous. Each element of the bill of material (BOM) matrix can be any non-negative integer. Comp...

Objective Polyethylenimine (PEI), a readily available synthetic polycation which has high transfection efficiency owing to its buffering capacity was introduced for transfection a few years ago. But it has been reported that PEI is cytotoxic in many cell lines. In this study, in order to enhance the transfection efficiency of 10 kDa PEI and reduce its toxicity, hydrophobic residues were grafte...

We develop exact simulation (also known as perfect sampling) algorithms for a family of assemble-to-order systems. Due to the finite capacity, and coupling in demands and replenishments, known solving techniques are inefficient for larger problem instances. We first consider the case with individual replenishments of items, and derive an event based representation of the Markov chain that allow...

To understand or to modify a biological pathway, the first step is to determine the patterns of coupling among its processes that are compatible with its input-output relation. Algorithms for this purpose have been devised for metabolic pathways, in which the reactions typically leave the enzymes unmodified. As shown here, one of these algorithms can also assemble molecular networks in which re...

This article introduces a novel approach for building heterogeneous ensembles based on genetic programming (GP). Ensemble learning is a paradigm that aims at combining individual classifiers outputs to improve their performance. Commonly, classifiers outputs are combined by a weighted sum or a voting strategy. However, linear fusion functions may not effectively exploit individual models’ redun...

Spatial organization of membranes into domains of distinct protein and lipid composition is a fundamental feature of biological systems. The plasma membrane is organized in such domains to efficiently orchestrate the many reactions occurring there simultaneously. Despite the almost universal presence of membrane domains, mechanisms of their formation are often unclear. Yeast cells feature promi...