Location tracking in mobile ad hoc networks using particle filters

Mobile ad hoc networks (MANETs) are dynamic networks formed on-the-fly as mobile nodes move in and out of each others' transmission ranges. In general, the mobile ad hoc networking model makes no assumption that nodes know their own locations. However, recent research shows that location-awareness can be beneficial to fundamental tasks such as routing and energy-conservation. On the other hand, the cost and limited energy resources associated with common, low-cost mobile nodes prohibits them from carrying relatively expensive and power-hungry location-sensing devices such as GPS. This paper proposes a mechanism that allows non-GPS-equipped nodes in the network to derive their approximated locations from a limited number of GPS-equipped nodes. In our method, all nodes periodically broadcast their estimated location, in terms of a compressed particle filter distribution. Non-GPS nodes estimate the distance to their neighbors by measuring the received signal strength of incoming messages. A particle filter is then used to estimate the approximated location, along with a measure of confidence, from the sequence of distance estimates. Simulation studies show that our solution is capable of producing good estimates equal or better than the existing localization methods such as APS-Euclidean for the more difficult scenario when the network connectivity is low.     

Photoacoustic system for on-line process monitoring of hydrogen sulfide (H2S) concentration in natural gas streams

A dual-channel hydrogen sulfide (H₂S) concentration measuring system based on photoacoustic spectroscopy is described. The system uses a single-mode, fiber-coupled, room-temperature-operated, telecommunication-type diode laser with a wavelength of 1574.5 nm and an output optical power of 40 mW and two identical resonant photoacoustic cells to achieve minimum detectable H₂S concentration at 0.5 ppm (3σ) in both measured natural gas streams. The instrument features excellent long-term stability and unattended automatic on-line monitoring even when operated in harsh industrial environments. The potentially deteriorating effect of temporal variation in the natural gas composition was successfully suppressed by applying a spectral baseline correction method and by introducing an additional measurement phase with measurement of a reference gas from which the H₂S has been removed. Various tests of the instrument demonstrate its reliable performance and suitability for process-control application. PACS 82.80.Kq; 42.62.Fi; 07.07.Df     

On finite pseudorandom sequences of k symbols

In earlier papers C. Mauduit and A. Sárközy have introduced and studied the measures of pseudorandomness for finite binary sequences. In [8] they extend this theory to sequences of k symbols: they give the definitions and also construct a “good” pseudorandom sequence of k symbols. In this paper these measures are studied for a “truely random” sequence.     

Use of capillary electrophoresis to monitor wheat maturation

Summary The maturation of wheat varieties with different harvest times has been examined by high-performance capillary electrophoresis. The unique proteins of the albumin, gliadin and glutenin fractions of Hungarian winter wheat cultivars Bánkúti 1201 (early harvest time), Martonvásári 23 (medium harvest time), and Martonvásári 15 (semi-late harvest time) were analysed. An acidic phosphate buffer containing a polymeric additive and organic modifiers was used in capillary zone electrophoresis mode. Formation of albumin followed the same time scale, and the patterns were quite similar, for all three cultivars. For gliadins and glutenins the time scale and patterns were different and some correlation was observed between harvest time and gliadin formation. Presented at Balaton Symposium '01 on High-Performance Separation Methods, Siófok, Hungary, September 2–4, 2001     

DSC and EPR investigation of the effect of fat crystallization on the consistency of butter

It was possible to determine the liquid fat content and melting behaviour of butters unenriched and enriched in low melting point milk fat fraction (mp=10?C) made from traditionally (6-11-11?C) and heat step technology ripened (6-20-11?C) cream by using EPR spectroscopy and ultrasensitive DSC methods. It was determined that

butters made from heat step technology (H) ripened cream have smaller liquid fat content in the continuous fat phase than that of made from traditionally (K) ripened cream.

there were different fat melting behaviours: the K-butter in temperature range of 0–20?C had one melting peak while H-butter had two ones, and

the effect of enrichment is different in the fraction of low melting point: the melting temperature decreased in the case of K-butter, but the H-butter exhibited smaller enthalpy at the lower melting temperature having same melting temperatures.

Our experiments support the view that H-butter is much more structured than K-butter which is caused by fat fragments containing cubic crystals, developed during the ripening of heat step technology. With respect to the minimum liquid fat content of maximum fat fragments, and vice versa, the cream ripening temperature of solid and spreadable butter can be optimalized by determination of cream ripening temperature-liquid fat content function (min.-max. curve) The experiments have proved without any doubt that butter of cold spreadable, not softening at room temerature, can be only produced by the combination of heat step cream ripening and enrichment with a low melting point fraction.     

Determination of Total Selenium Content in Cereals and Bakery Products by Flow Injection Hydride Generation Graphite Furnace Atomic Absorption Spectrometry Applying in-situ Trapping on Iridium-Treated Graphite Platforms

A flow injection hydride generation graphite furnace atomic absorption spectrometric (FI-HG-GFAAS) method was applied to the determination of Se in Se-doped and undoped cereals and bakery products. For the purpose of doping, the soils used for the cultivation of the cereals were dosed with Se-doped foliar fertilizers. The samples were dissolved in a mixture of HNO₃ and H₂O₂ solutions using microwave-assisted digestion. The decomposition of H₂Se generated from the sample solutions and the trapping of elemental Se were performed at a temperature of 300°C on an Ir-pretreated integrated graphite platform of a transversally heated graphite atomizer (THGA). For release of the trapped Se within a fairly short atomization time (5s), an atomization temperature of 2200°C was observed to be optimal. The overall efficiency of hydride generation, transport and trapping was 86%.The upper limit of the linear dynamic range of calibration was 10µgL^–1, which corresponds to 0.5µgg^–1 for solid samples. Recovery of the samples spiked with Se^VI solutions was found to be 93±6% on average. The relative standard deviation of the determinations was less than 8%. The limit of detection was found to be 0.06µgL^–1, corresponding to 3ngg^–1 for solid samples. The accuracy of the method was verified with the use of IAEA-155 (whey powder) certified reference material. End-capped THGA tubes resulted in an extension of the linear calibration range compared to that of standard THGAs.The Se content in bakery products made of undoped cereals ranged from 7.7 to 68ngg^–1 (wet weight) in 18 samples, whereas the Se content of the corresponding cereals was found to be below 100ngg^–1 (wet weight). The Se level of cereals grown on soils treated with Se-doped fertilizers ranged from 128 to 1046ngg^–1 (wet weight), and it depended linearly on the Se concentration of the corresponding foliar fertilizer.     

Polar effect in the reaction of CH3O with HBr

The discharge flow method with laser induced fluorescence detection of CH₃O was applied to determine the rate constant, k ₁, for the reaction CH₃O + HBr → products (1) k ₁ (298 K) = (8.41 ± 0.80(1σ)) 10¹¹ cm³ mol^-1 s^-1. The unusually large k ₁ value was explained by the polar nature of the transition state of the reaction. This revised version was published online in June 2006 with corrections to the Cover Date.     

Capillary electrophoretic separation of mono- and dimaltosyl-β-cyclodextrins and determination of the stability constants of their benzoate complexes

Summary Capillary zone electrophoresis method has been developed for the separation (and determination) of monoand dimaltosyl-β-cyclodextrins using indirect UV absorbance detection. The separation is based on inclusion complex formation with benzoate ion which is used as background electrolyte and absorbance provider simultaneously. Good resolution of cyclodextrin mixtures can be achieved optimizing the pH and the benzoic acid concentration in the background electrolyte. Capillary zone electrophoresis method has also been developed for the determination of formation constants of inclusion complexes.     

Beiträge zur Chemie der Pyrrolpigmente, 3. Mitt.1: Die NH-Tautomerie von substituierten Pyrromethenen: Protonenresonanzspektrometrische Untersuchungen

NMR-spectra of several pyrromethenes were measured at different temperatures, concentrations and in different solvents. The chemical shifts of all protons were assigned and long range coupling constants determined. This variation of temperature, concentration and solvent provided evidence forintra- andinter-molecular proton transfer. In all pyrromethenes investigated the tautomeric NH exchanges are too fast—even at –100°C—to be measured by NMR.

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