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Polyferrocenyldimethylsilane (PFS) diblock copolymers with polyisoprene (PFS-PI) or with polydimethylsiloxane (PFS-PDMS) self-assemble in simple alkane solvents to form what appear by TEM to be dense flexible cylinders (nanowires) or "nanotube-like" structures. Typical widths are on the order of 20 to 30 nm, with variable lengths often greater than 10 μm. The structures that form, and the dimensions of the "tube-like" structures or wires, depend upon the composition of the polymers and the lengths of the blocks. Light scattering experiments show that the PFS-PDMS (block ratio 1:12) solutions aged at 25°C contain long thin objects 950 nm in length. These structures probably rearrange on the TEM grid as the solvent evaporates to form elongated structures. Establishing a mechanistic connection between the objects present in solution and those seen in the TEM images, as well as understanding the factors that lead to these unusual self-assembled structures, remain a challenge. [ABSTRACT FROM AUTHOR]

The IEEE 802.11 MAC layer is known for its unfairness behavior in ad hoc networks. Introducing fairness in the 802.11 MAC protocol may lead to a global throughput decrease. It is still a real challenge to design a fair MAC protocol for ad hoc networks that is distributed, topology independent, that relies on no explicit information exchanges and that is efficient, i.e. that achieves a good aggregate throughput. The MadMac protocol deals with fairness and throughput by maximizing aggregate throughput when unfairness is solved. Fairness provided by MadMac is only based on information provided by the 802.11 MAC layer and adds a non-probabilistic modification in 802.11. MadMac has been tested in many configurations that are known to be unfair. In these configurations, MadMac provides a good aggregate throughput while solving the fairness issues. [ABSTRACT FROM AUTHOR]

An important requirement of a robust traffic engineering solution is insensitivity to changes, be they in the form of traffic fluctuations or changes in the network topology because of link failures. In this paper we focus on developing a fast and effective technique to compute traffic engineering solutions for Interior Gateway Protocol (IGPs) environments that are robust to link failures in the logical topology. The routing and packet forwarding decisions for IGPs is primarily governed by link weights. Our focus is on computing a single set of link weights for a traffic engineering instance that performs well over all single logical link failures. Such types of failures, although usually not long lasting, of the order of tens of minutes, can occur with high enough frequency, of the order of several a day, to significantly affect network performance. The relatively short duration of such failures coupled with issues of computational complexity and convergence time due to the size of current day networks discourage adaptive reactions to such events. Consequently, it is desirable to a priori compute a routing solution that performs well in all such scenarios. Through computational evaluations we demonstrate that our technique yields link weights that perform well over all single link failures and also scales well, in terms of computational complexity, with the size of the network. Keywords: Routing, Traffic Engineering, IGP, Optimization, link failures. [ABSTRACT FROM AUTHOR]

The focus of this paper is on developing and evaluating a practical methodology for determining if and when different types of traffic can be safely multiplexed within the same service class. The use of class rather than individual service guarantees offers many advantages in terms of scalability, but raises the concern that not all users within a class see the same performance. Understanding when and why a user will experience performance that differs significantly from that of other users in its class is, therefore, of importance. Our approach relies on an analytical model developed under a number of simplifying assumptions, which we test using several real traffic traces corresponding to different types of users. This testing is carried out primarily by means of simulation, to allow a comprehensive coverage of different configurations. Our findings establish that although the simplistic model does not accurately predict the absolute performance that individual users experience, it is quite successful and robust when it comes to identifying situations that can give rise to substantial performance deviations within a service class. As a result, it provides a simple and practical tool for rapidly characterizing real traffic profiles that can be safely multiplexed. [ABSTRACT FROM AUTHOR]

Several nuclear mechanisms involve specific DNA-protein interactions. The electrophoretic mobility shift assay (EMSA, also known as the gel mobility shift or gel retardation assay), first described almost two decades ago (1,2), provides a simple, efficient and widely used method to study such interactions. Its ease of use, its versatility, and especially its high sensitivity (10−18 mol of DNA [2]) make it a powerful method that has been successfully used in a variety of situations not only in gene regulation analyzes but also in studies of DNA replication, repair, and recombination. Although very useful for qualitative purposes, EMSA has the added advantage of being suitable for quantitative and kinetic analyzes (3). Furthermore, because of its very high sensitivity, EMSA makes it possible to resolve complexes of different protein or DNA stoichiometry (4) and even to detect conformational changes. [ABSTRACT FROM AUTHOR]

We present two portable algorithms for the List Ranking Problem in the Coarse Grained Multicomputer model (CGM) and we report on experimental studies of these algorithms. With these experiments, we study the validity of the chosen CGM model, and also show the possible gains and limits of such algorithms. [ABSTRACT FROM AUTHOR]

We present our work on the APPRYL PP2 polypropylene plant. We give a physical nonlinear model of the system with a delay on one of the two inputs. This model is flat. Using this flatness property, we show how to design a controller capable of fast and precise transients. Industrial results prove the relevance of our approach. Our controller is in full service since July 1999. [ABSTRACT FROM AUTHOR]

The use of PC clusters interconnected by high performance local networks is one of the major current trends in parallel/distributed computing. We give coarse-grained, BSP-like, parallel algorithms to solve many problems arising in the context of interval graphs, namely connected components, maximum weighted clique, BFS and DFS trees, minimum interval covering, maximum independent set and minimum dominating set. All of the described p-processor parallel algorithms require only constant or O(log p) number of communication rounds and are efficient in practice, as demonstrated by our experimental results obtained on a Fast Ethernet based PC cluster. [ABSTRACT FROM AUTHOR]

A simple mechanism is presented, based on ant-like agents, for routing and load balancing in telecommunications networks, following the initial works of Appleby and Stewart [1] and Schoonderwoerd et al. [32,33]. In the present work, agents are very similar to those proposed by Schoonderwoerd et al. [32,33], but are supplemented with the ability to perform more computations at switching nodes, which significantly improves the network's relaxation and its response to perturbations. [ABSTRACT FROM AUTHOR]