Fast Public Transit Routing with Unrestricted Walking Through Hub Labeling
ANALYSIS OF EXPERIMENTAL ALGORITHMS, SEA2 2019
Authors: Duc-Minh Phan; Viennot, Laurent
Abstract
We propose a novel technique for answering routing queries in public transportation networks that allows unrestricted walking. We consider several types of queries: earliest arrival time, Pareto-optimal journeys regarding arrival time, number of transfers and walking time, and profile, i.e. finding all Pareto-optimal journeys regarding travel time and arrival time in a given time interval. Our techniques uses hub labeling to represent unlimited foot transfers and can be adapted to both classical algorithms RAPTOR and CSA. We obtain significant speedup compared to the state-of-the-art approach based on contraction hierarchies. A research report version is deposited on HAL with number hal-02161283.
A new durable pigment with hydrophobic surface based on natural nanotubes and indigo: Interactions and stability
JOURNAL OF COLLOID AND INTERFACE SCIENCE
Authors: Zhuang, Guanzheng; Jaber, Maguy; Rodrigues, Francisco; Rigaud, Baptiste; Walter, Philippe; Zhang, Zepeng
Abstract
Covering with polyorganosilane (POS) was proved as an effective way to enhance the chemical and thermal stability of clay/dye hybrid pigments. But the photostability and interactions with clay minerals, dyes and POS layer has never been reported. In order to investigate above issues, new organic-inorganic hybrid pigments based on halloysite (Hal) and indigo (In) were prepared by grinding method. X-ray diffraction, transmission electron microscopy, thermogravimetry, Fourier transform infrared spectroscopy were applied to characterize the structure of In-Hal (without POS layer) and In-Hal-POS (with POS layer) pigments. Solid state nuclear magnetic resonance (NMR) was employed to reveal the interactions between Hal, In and POS. Reflection spectra and CIE 1976 color space system were used to evaluate the color parameters and color changes of pigments. Thermal stability, chemical resistance to ethanol, 1 mol.L-1 HCl and 1 mol.L-1 NaOH, and light fastness to visible light were tested. Indigo molecules dispersed on the surface of Hal nanotubes. POS layer homogeneously covered on the surface of hybrid pigments, without changing the crystal structure and morphology of Hal. Covering with POS layer seldomly affect the color of hybrid pigments. However, In-Hal-POS exhibited better stability than In-Hal, due to hydrophobic surface which can prevent indigo molecules from chemical reactions and degradation. A new route was proposed to prepare organic-inorganic hybrid pigments, ignoring the interaction between dye molecules and substrates. (C) 2019 Elsevier Inc. All rights reserved.