Noise source importance in linear stochastic models of biological systems that grow, shrink, wander, or persist

While noise is an important factor in biology, biological processes often involve multiple noise sources, whose relative importance can be unclear. Here we develop tools that quantify the importance of noise sources in a network based on their contributions to variability in a quantity of interest. We generalize the edge importance measures proposed by Schmidt and Thomas [1] for first-order reaction networks whose steady-state variance is a linear combination of variance produced by each directed edge. We show that the same additive property extends to a general family of stochastic processes subject to a set of linearity assumptions, whether in discrete or continuous state or time. Our analysis applies to both expanding and contracting populations, as well as populations obeying a martingale (“wandering”) at long times. We show that the original Schmidt-Thomas edge importance measure is a special case of our more general measure, and is recovered when the model satisfies a conservation constraint

Research of the Influence of Geometric Parameters of Rooms for Sound Insulation of Lightweight Partitions

Состояние проблемы. Звукоизоляция легких перегородок значительно зависит от места их установки в здании. Необходимы исследования структуры звукового поля в несоразмерных помещениях и анализ его влияния на звукоизоляцию легких ограждений. Результаты. Проведены натурные и лабораторные экспериментальные исследования звукоизоляции каркасно-обшивной перегородки, установленной в коридоре. Для случая соразмерного помещения получена хорошая сходимость результатов. Теоретически исследована структура звукового поля при зеркальном отражении звука (с использованием метода прослеживания лучей). Выполнены расчеты с получением распределений долей осевых, касательных и косых лучей в помещениях, расчеты уровней интенсивности звуковых волн, падающих на боковые стены и потолок коридора. Учитывалось положение источника шума относительно перегородки и других ограждений. Выводы. Пропорции помещений влияют на звукоизоляцию легких ограждений. В диапазоне ниже граничной частоты диффузности несоразмерного помещения с источником шума структура звукового поля неоднородная, звуковые лучи падают на ограждение неравномерно с различных направлений. Это приводит к уменьшению совпадений мод колебаний в воздухе и в ограждающей конструкции, частотная характеристика звукоизоляции ограждения имеет пикообразный вид. Statement of the problem. Sound insulation of lightweight partitions depends significantly on the place of installation in the building. It is necessary to study the structure of the sound field in disproportionate rooms and analyze its effect on the sound insulation of light enclosures. Results. Natural and laboratory experimental studies of the sound insulation of the frame partitions installed in the corridor were carried out. For the case of a commensurate room, good convergence of the results was obtained. The structure of the sound field with mirror reflection of sound has been theoretically investigated using the method of tracing of sound rays. Calculations were performed to obtain the distributions of the proportions of axial sound rays, tangential sound rays, oblique sound rays in the premises, and the calculations of the intensity levels of sound waves incident on the lightweight partition and other enclosures of the corridor. The position of the noise source relative to the lightweight partition and other enclosures of the corridor was taken into account. Conclusions. The proportions of the rooms affect the sound insulation of lightweight enclosures. The structure of the sound field of a disproportionate room with a noise source is non-uniform in the range below the boundary frequency of diffuse sound field. Sound rays fall on the lightweight partition unevenly from different directions. This leads to a decrease in the coincidence of wave modes in the air and wave modes in the lightweight partition. The frequency characteristic of the sound insulation of the lightweight partition has a peak-like appearance.

Joint Correction of Tropospheric and Orbital Errors in SAR Differential Interferograms

Synthetic Aperture Radar (SAR) satellite imagery is a source of data widely employed in the quantification and analysis of an earthquake coseismic displacement. However, due to the signal path along the atmosphere and to other sources, the interferometric phase becomes compromised. In this work, a methodology for the correction of tropospheric and orbital errors in the differential interferogram is presented. This methodology was applied to a couple of Sentinel-1A data. The phenomenon studied was the 11th November 2018 Zeribet el Oued earthquake, Mw. 5.2 (The state of Biskra, South East of Algeria). It was possible to correct both tropospheric and orbital errors, where the dominant one was the tropospheric delay, a displacement error of 4 cm was added to the differential interferogram by this noise source. The correction of orbital error led to a better interpretation of the coseismic displacement.

Identification of Turbomachinery Noise Sources via Processing Beamforming Data Using Principal Component Analysis

Complex turbomachinery systems produce a wide range of noise components. The goal is to identify noise source categories, determine their characteristic noise patterns and locations. Researchers can then use this information to quantify the impact of these noise sources, based on which new design guidelines can be proposed. Phased array microphone measurements processed with acoustic beamforming technology provide noise source maps for pre-determined frequency bands (i.e., bins) of the investigated spectrum. However, multiple noise generation mechanisms can be active in any given frequency bin. Therefore, the identification of individual noise sources is difficult and time consuming when using conventional methods, such as manual sorting. This study presents a method for combining beamforming with Principal Component Analysis (PCA) methods in order to identify and separate apart turbomachinery noise sources with strong harmonics. The method is presented through the investigation of Counter-Rotating Open Rotor (CROR) noise sources. It has been found that the proposed semi-automatic method was able to extract even weak noise source patterns that repeat throughout the data set of the beamforming maps. The analysis yields results that are easy to comprehend without special prior knowledge and is an effective tool for identifying and localizing noise sources for the acoustic investigation of various turbomachinery applications.

Assessment of acoustic pollution of areas bordering highways

The work is devoted to the peculiarities of acoustic pollution of roadside territories. The studied territory is characterized by uneven acoustic load on the experimental sections of the highways of the Republic of Crimea, which is associated with the peculiarities of traffic flow and technical characteristics of cars. The article considers the indicators of the equivalent and maximum levels of motor vehicle noise. As the research result, the excess of noise level from 10 to 30 dBA was revealed. The maximum level of acoustic pollution was recorded in 10-meter zone, at a distance of 30 m from the noise source the level of acoustic pollution is reduced to 5-10 dBA.

Investigation Forecasting Methods of Noise Level From Rail Trams in Lviv City

The method of localization of noise level calculation from a rail vehicle in the city of Lviv is investigated and developed. Models of noise load measurement have been adapted, the measured values have been unified and our own solution has been created on the basis of the road surface, the speed of rail transport and the distance from the noise source. According to the research methods, namely: Schall 03 (from Germany), Nordic Train (Scandinavian countries) was carried out compared to the Bland—Altmann schedule, with which we can adapt the studied results. distance from the noise source. As a result, models for predicting noise load measurements were adapted. The results were carried out compared to the Bland-Altmann plot, which helped us with the comparison table. The purpose of the study is to analyze methods for noise level measurements and adapt them into our realities. Based on the known methods of measuring the noise load of railway vehicles, we can assume that there are no correct methods for the cities of Ukraine (especially Lviv).

Effects of Noise and Control in Mine Operation

Noise and noise induced hearing loss (NIHL) in the workplace is a serious issue. Not only can it affect hearing, it can also affect ability to work safely. This is because noises make it difficult to hear instructions or safety warnings. Mine workers each have a responsibility for safety in relation to noise. This paper informs underground and surface mine operators and mine workers to recognise, manage and control risks associated with occupational noise exposure. It explains the health effects of noise, source and noise exposure types; measurement of exposure standards and control measures that can reduce these risks.