Температурный дрейф собственных частот микромеханического гироскопа

Целью работы является определение характеристик влияниятемпературного воздействия на собственные частоты микромеханического гироскопа, чувствительный элемент которого расположен на кремниевой пластине с кристаллографической ориентацией (111), имеющей изотропию механических и температурных свойств во всех направлениях. Необходимость контроля метрологических характеристик, зависящих от собственных частот во всем температурном диапазоне, подтверждает актуальность данной темы исследования. В ходе исследования в среде ANSYS проведен температурно-модальный анализ модели, имитирующей первичные колебания микромеханического гироскопа. Модель микрорезонатора, выбранная в качестве имитатора первичных колебаний микромеханического гироскопа, адекватно отражает характер колебаний массы по оси первичных колебаний. В результате получены температурные зависимости собственных частот и определены наиболее температурно-независимые моды колебаний для осциллятора, выполненного на кремниевой пластине с кристаллографической ориентацией (111)

Demand, supply, and restraint: Determinants of domestic water conflict and cooperation

This article focuses on one of the most likely empirical manifestations of the "environment-conflict" claim by examining how demand for and supply of water may lead to domestic water conflict. It also studies what factors may reduce the risk of conflict and, hence, induce cooperation. To this end, the article advances several theory-based arguments about the determinants of water conflict and cooperation, and then analyzes time-series cross-section data for 35 Mediterranean, Middle Eastern, and Sahel countries between 1997 and 2009. The empirical results show that demand-side drivers, such as population pressure, agricultural productivity, and economic development are likely to have a stronger impact on water conflict risk than supply-side factors, represented by climate variability. The analysis also reveals that violent water conflicts are extremely rare, and that factors conducive to restraint, such as stable political conditions, may stimulate cooperation. Overall, these results suggest that the joint analysis of demand, supply, and restraint improves our ability to account for domestic water-related conflict and cooperation

Convolutive Blind Signal Separation Spatial Effectiveness in Speech Intelligibility Improvement

Blind signal separation is one of the latest methods to improve the signal to noise ratio. The main objective of blind source separation is the transformation of mixtures of recorded signals to obtain each source signal at the output of the procedure, assuming that they are statistically independent. For acoustic signals it can be concluded that the correct separation is possible only if the source signals are spatially separated. That finding suggests analogies with the classical spatial filtering (beamforming). In this study we analyzed an effect of the angular separation of two source signals (i.e. speech and babble noise) to improve speech intelligibility. For this purpose, we chose the blind source separation algorithm based on the convolutive separation, based on second order statistics only. As a system of sensors a dummy head was used (one microphone inside each ear canal), which simulated two hearing aids of a hearing impaired person. The speech reception threshold, before and after the blind source separation was determined. The results have shown significant improvement in speech intelligibility after applying blind source separation (speach reception threshold fell even more than a dozen dB) in cases where the source signals were angularly separated. However, in cases where the source signals were coming from the same directions, the improvement was not observed. Moreover, the effectiveness of the blind source separation, to a large extent, depended on the relative positions of signal sources in space

Informationsgesellschaft und schweizerische Sicherheitspolitik

ISSN:1423-389

Estimating the population exposed to transportation noise: a case study on Poznań City

European Union Directive 2002/49/EC relating to the assessment and management of environmental noise (named as END) in article 6 paragraph 3 states that “harmful effects may be assessed by means of dose-effect relations referred to in ANNEX III”. In this still unfinished ANNEX III there are formulas which present how to calculate the number of people affected by a given noise. The dose-effect relations have been recently presented in WHO document “Environmental Noise Guidelines for the European Region”. These Guidelines allow to predict the percentage of people who will be affected by a specific kind of noise. E.g. it is shown how to calculate the percentage of highly annoyed people for a given value of noise index, Lden. In our paper we propose how to calculate the total number of people affected by noise in their living conditions and discuss the implementation of methods recommended in ANNEX III in Poland

Bulletin 1999 zur schweizerischen Sicherheitspolitik

ISSN:1024-060