نتایج جستجو برای: flicker

تعداد نتایج: 3028  

Voltage flicker phenomenon is one of the main power quality problems in today's power networks. Before any compensation operation for this phenomenon, the location of each flicker sources must be identified and the effect of each of them on the network flicker value must be determined. Also, methods that require least number of monitoring points are more in demand due to the limitations of meas...

Journal: :journal of artificial intelligence in electrical engineering 2012
saeid jalilzade mehdi mardani

measurement of magnitude and frequency of the voltage flicker is very important for monitoring andcontrolling voltage flicker efficiently to improve the network power quality. this paper presents twonew methods for measurement of flicker signal parameters using shuffled frog leaping algorithm(sfla) and imperialist competitive algorithm (ica). this paper estimates fundamental voltage andflicker ...

Measurement of magnitude and frequency of the voltage flicker is very important for monitoring andcontrolling voltage flicker efficiently to improve the network power quality. This paper presents twonew methods for measurement of flicker signal parameters using Shuffled Frog Leaping Algorithm(SFLA) and Imperialist Competitive Algorithm (ICA). This paper estimates fundamental voltage andflicker ...

Background: Computer usage has rapidly grown. This is because it helps to resolve problems, i.e., encountered in daily life by individuals. Various monitor screens that have been developed affect the userchr('39')s eyes. Screen size is one of the relevant impacts. Thus, this study compared the immediate effects of two computer screen sizes on visual fatigue in Video Display Terminal (VDT) users...

2010
Abdolaziz Ashrafian Mehrdad Rostami

In this paper, a method based on continuous wavelet transform is suggested for calculation of flicker power. The flicker power can be utilized to identify the flicker direction to a flicker source with respect to a monitoring point. In our proposed method, using continuous Gaussian wavelet transform, pure flicker waveforms are extracted from the measured voltage and current signals. The flicker...

بابایی ترکمانی, مهدی, رستگار, حسن,

Natural gas is transmitted at high pressure levels. For industrial and domestic consumptions, this pressure should be reduced. Usually, mechanical valves accomplish this process. Turbo-expanders can replace these equipments and reduce gas pressure at city gate gas pressure reduction stations as well. Besides, they can recover the huge amount of high pressure gas energy and drive electrical gene...

Journal: :Vision Research 2000
Andrew J Anderson Algis J Vingrys

We investigated the interactions between flicker thresholds and luminance pedestals using threshold versus contrast (TvC) and method of constant stimuli paradigms. High amplitude luminance pedestals were found to elevate flicker thresholds, but low amplitude luminance pedestals were unable to reduce flicker thresholds. Luminance pedestals elevated flicker thresholds more at low temporal frequen...

Journal: :Investigative ophthalmology & visual science 2002
Benedetto Falsini Charles E Riva Eric Logean

PURPOSE Visual flicker induces a response in human optic nerve blood flow (F(onh)) and inner retinal activity, as assessed by laser Doppler flowmetry and electroretinogram (ERG), respectively. In this study the relationship was examined between the flicker-evoked changes in F(onh) (RF(onh)) and ERG when various parameters of the stimulus were varied. METHODS In five normal observers (mean age...

Journal: :Journal of vision 2009
Richa Verma Michael J Pianta

We aimed to noninvasively estimate the relative contribution of the cone photoreceptors to the photopic flicker electroretinogram (ERG) in humans. Responses to ganzfeld square-wave flicker (15, 30, and 60 Hz) were recorded in the presence of a rod-saturating background. We used a modified paired flash technique in which a bright probe flash was presented at different times during a flicker cycl...

2017
Anthony E. Felder Justin Wanek Norman P. Blair Mahnaz Shahidi

Purpose To mathematically model the temporal dynamic responses of retinal vessel diameter (D), oxygen saturation (SO2), and inner retinal oxygen extraction fraction (OEF) to light flicker and to describe their responses to its cessation in humans. Methods In 16 healthy subjects (age: 60 ± 12 years), retinal oximetry was performed before, during, and after light flicker stimulation. At each ti...

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