نتایج جستجو برای: noise sources

تعداد نتایج: 473529  

In this paper, an intuitive analysis of a phase noise reduction technique is done, and then a modified structure is proposed to achieve higher phase noise reduction than the original one. This method reduces the impact of noise sources on the phase noise by decreasing closed-loop gain in zero-crossings points and moving this high closed-loop gain to the non-zero-crossings points. This reduction...

Journal: :international journal of occupational hygiene 0
parvin nassiri department of occupational health, school of public health, tehran university of medical sciences, tehran, iran. hamidreza heidari research center for environmental pollutants, qom university of medical sciences, qom, iran. monireh khadem department of occupational health, school of public health, tehran university of medical sciences, tehran, iran. hoda rahimifard department of occupational health, school of public health, qom university of medical sciences, qom, iran. elham rostami department of epidemiology and biostatistics, school of public health, tehran university of medical science, tehran, iran.

noise is a common and widespread problem in workplaces. noise can lead to hearing loss, hypertension, nervous and mental disorders, annoyance and stress, sleep disturbance, negative impact on productivity and working capacity. the undesirable effects of noise on an individual or group are called annoyance. some personal and social characteristics can affect on annoyance. this study was aimed to...

Ali Khatibi Amir Hossein Batouli Hamed Dehghani Mohammad Ali Oghabian,

Introduction: Functional MRI methods have been used to study sensorimotor processing in the brain and the Spinal cord. However, these techniques confront unwanted contributions to the measured signal from physiological fluctuations. For the spinal cord imaging, most of the challenges are consequences of cardiac and respiratory movement artifacts that are considered as signifi...

آتشبار, محمود, کهائی, محمدحسین,

In this paper we propose the spatial sparsity based WCSSDOA method for multi speakers' Direction of arrival estimation. In the proposed method the sparse modeling is done based on the sensor signals' correlation matrix, which leads to low computational complexity. In this method the SVD decomposition of the noise covariance matrix is proposed to reach the free noise sparse model, which leads to...

Journal: :journal of research in health sciences 0
rostam golmohammadi mohammad reza monazzam maryam nourollahi ali nezafat samaneh momen bellah fard

background: the adverse effects of noise are well known and noise problems due to industrialization of communities are increasing over the time. oil industries due to the process and nature of production; contain many noise sources such as compressors, turbines, and pumps, which cause excessive noise exposure. the objective of this study was to evaluate the noise characteristics of compressors ...

Introduction: Electrocardiogram (ECG) is a method to measure the electrical activity of the heart which is performed by placing electrodes on the surface of the body. Physicians use observation tools to detect and diagnose heart diseases, the same is performed on ECG signals by cardiologists. In particular, heart diseases are recognized by examining the graphic representation of heart signals w...

Journal: :تحقیقات نظام سلامت 0
رستم گلمحمدی دانشیار گروه مهندسی بهداشت حرفه‎ای، دانشکده بهداشت و مرکز تحقیقات علوم بهداشتی، دانشگاه علوم پزشکی همدان، همدان، ایران محسن علی آبادی ستادیار گروه مهندسی بهداشت حرفه‎ای، دانشکده بهداشت، دانشگاه علوم پزشکی و خدمات بهداشتی درمانی همدان، همدان، ایران ابراهیم درویشی عضو مرکز تحقیقات بهداشت محیط و مربی گروه مهندسی بهداشت حرفه‎ای، دانشکده بهداشت، دانشگاه علوم پزشکی و خدمات بهداشتی درمانی کردستان، سنندج، ایران

background: in the steel industry, coke-fueled furnaces are used for smelting iron ore to produce cast iron are considered as sources of annoying noise.this study aims to evaluate the noise pollution blast furnace and sound source characteristics in order to present noise control measures in the steel industry. methods: measurement of noise level and its frequency analysis was performed using s...

This paper describes an efficient edge-preserved regularization algorithm for downward continuation of magnetic data in detection of unexploded ordnance (UXO). The magnetic anomalies arising from multi-source UXO can overlap at a height over the ground surface, while causative sources may not be readily separated due to low level of signal-to-noise ratio of the observed data. To effectively the...

Journal: Pollution 2015

Noise is one of the main parameters to be considered to achieve a healthy indoor ambience in ferries. Therefore, the noise standards need to be more specialized and specifically based on real sampled data and case studies. In the present research, the noise levels in a ship, under different working conditions, were sampled and compared with those specified in the new and old standards. An initi...

Noise is one of the main parameters to be considered to achieve a healthy indoor ambience in ferries. Therefore, the noise standards need to be more specialized and specifically based on real sampled data and case studies. In the present research, the noise levels in a ship, under different working conditions, were sampled and compared with those specified in the new and old standards. An initi...

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