École Polytechnique Fédérale de Lausanne
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Efficient Peer-to-Peer Belief Propagation
Get PDFIn this paper, we will present an efficient approach for distributed inference. We use belief propagation's message-passing algorithm on top of a DHT storing a Bayesian network. Nodes in the DHT run a variant of the spring relaxation algorithm to redistribute the Bayesian network among them. Thereafter correlated data is stored close to each other reducing the message cost for inference. We simulated our approach in Matlab and show the message reduction and the achieved load balance for random, tree-shaped, and scale-free Bayesian networks of different sizes. As possible application, we envision a distributed software knowledge base maintaining encountered software bugs under users' system configurations together with possible solutions for other users having similar problems. Users would not only be able to repair their system but also to foresee possible problems if they would install software updates or new applications.LSI
Solvent Effect on Redox Properties of Hexanethiolate Monolayer-Protected Gold Nanoclusters
Get PDFThe capacitance of monolayer-protected gold nanoclusters (MPCs), CMPC, in solution has been theoretically reconsidered from an electrostatic viewpoint, in which an MPC is considered as an isolated charged sphere within two dielectric layers, the intrinsic coating monolayer, and the bulk solvent. The model predicts that the bulk solvent provides an important contribution to CMPC and influences the redox properties of MPCs. This theoretical prediction is then examined experimentally by comparing the redox properties of MPCs in four organic solvents: 1,2-dichloroethane (DCE), dichloromethane (DCM), chlorobenzene (CB), and toluene (TOL), in all of which MPCs have excellent solubility. Furthermore, this set of organic solvents features a dielectric constant in a range from 10.37 (DCE) to 2.38 (TOL), which is wide enough to probe the solvent effect. In these organic solvents, tetrahexylammonium bis(trifluoromethylsulfonyl)imide (THATf2N) is used as the supporting electrolyte. Cyclic and differential pulse voltammetric results provide concrete evidence that, despite the monolayer protection, the solvent plays a significant effect on the properties of MPCs in solution.LEP
Metabolic engineering under uncertainty-II: Analysis of yeast metabolism
No full textYeast metab. has been used extensively in scientific investigations and industrial applications. Understanding the properties of the yeast metabolic network is crucial, yet unaccomplished due to its high complexity, the different culture conditions, and the uncertainty assocd. with kinetic parameters. We recently developed a computational and math. framework using Monte Carlo method in which parameter uncertainty can be addressed through large-scale sampling procedure. This framework was applied on the compartmentalized central carbon pathways of Saccharomyces cerevisiae metab. considering the growth environment of batch and chemostat reactor and integrating information from metabolic flux anal. Statistical anal. of the results indicates that yeast cells growing in batch culture condition exhibit dramatically different control schemes from those growing in a chemostat. The difference is mainly due to the feedback introduced by the constraints of the chemostat. The control of the enzymes on the rates of the substrate uptake, product excretion, and cell growth and its practical implication are discussed. Clustering of the reaction steps according to the similarity of their responses to enzyme activity perturbations reveals functional coupling of metabolic reactions. [on SciFinder (R)]LCSB16-8 FIELD Section Title:Fermentation and Bioindustrial Chemistry10, 48Department of Chemical and Biological Engineering,Northwestern University,Evanston,IL,USA. FIELD URL:written in English
A dead-reckoning technique for streaming virtual human animation
No full textIn networked virtual environments (NVEs), users are represented by their virtual embodiments. The articulated structure of these embodiments introduces a new complexity in the representation and streaming of animations, especially when the number of participants in the simulation increases. This requires real-time algorithms to decrease the networking overhead. The dead-reckoning technique is a way to reduce the required bit rate, and has been used for simple nonarticulated objects in popular NVE systems. We introduce a dead-reckoning technique for articulated virtual human figures, based on the MPEG-4 body animation specification, using Kalman filteringVRLABComput Graphics Lab., Fed. Inst. of Technol., Lausanne, Switzerlan
On the geometry of a modern imaging diffractometer
No full textThe geometry of a modern imaging diffractometer is discussed in detail. A method to find all relevant instrument parameters from the control single-crystal measurement data is proposed and the limitations of such a procedure are indicated. Optimization of the instrument parameters by the least-squares method is presented. [References: 19]LCRMay
L'analyse de performance sportive à l'aide d'un système GPS/INS low-cost: évaluation de capteurs inertiels de type MEMS
Get PDFLes skieurs s'intéressent au GPS (Global Positioning System) pour évaluer leurs performances. Les positions enregistrées durant les entraînements et les courses permettent d'analyser les trajectoires et de comparer vitesses, accélérations et autres paramètres liés à la performance sportive (p. ex. la fréquence cardiaque). Malheureusement, l'environnement montagneux, la dynamique relativement élevée du skieur et les restrictions ergonomiques dépassent souvent les limites technologiques actuelles.TOP
A Theoretical Model for Prediction of the Critical Heat Flux CHF in Heated Microchannels
No full textLTC
Non-Cytotoxic, Bifunctional EuIII and TbIII Luminescent Macrocyclic Complexes for Luminescence Resonant Energy- Transfer Experiments
No full textA new macrocyclic ligand, , has been synthesised, based on the cyclen framework grafted with three phenacyl light-harvesting groups and a C5-alkyl chain bearing a carboxylic acid function as a potential linker for biological material. Acidity constants are determined by spectrophotometric titrations, as well as conditional stability constants for the resulting 1:1 complexes with trivalent lanthanide ions. The complexes have stabilities comparable to 1,4,7,10-tetrakis(carbamoylmethyl)- 1,4,7,10- tetraazacyclododecane (dtma) complexes, with . Photophysical properties of the ligand and of the and complexes have been determined for both microcrystalline samples and solutions in water and acetonitrile. They point to the metal ion being present in an environment with axial symmetry derived from the point group. The hydration number determined for decreases with increasing pH value and becomes fractional at pH 7.5, which points to an equilibrium between two differently solvated species and probably to the participation of the deprotonated carboxylic acid chain in the complexation. The quantum yields in water (1.9% for , 3.4% for ) are smaller than those for complexes with the symmetrically substituted parent macrocycle, but efficient luminescence resonant energy transfer (LRET) was observed when Cy5 dye was added to the solutions. Finally, the influence of the complex on cell viability is tested on both malignant (5D10 mouse hybridoma, Jurkat human T leukaemia, MCF-7 human breast carcinoma) and non-malignant (Hacat human keratinocyte) cell lines. Cell viability after 24 h incubation at with was >90% for all cell lines, except Jurkat (>70%). All of these properties make complexes interesting potential probes for bioanalyses.LCS