نتایج جستجو برای: شاخص zsi
تعداد نتایج: 74623 فیلتر نتایج به سال:
We apply an objective statistical analysis to a 6-yr, multiparameter dataset iti an c4l’ort lo tlctic~ibe the spatial dependence and inherent variation of water quality patterns in the lilorida Ray-Whitrwalc*r Hny area. Principal component analysis of 16 water quality parameters collected monthly over a 6-yr period resnlted in live prinr.ipaI COIIIponents (PC) that explained 71.8% of the varian...
drought monitoring is a fundamental component of drought risk management. it is normally performed using various drought indices that are effectively continuous functions of rainfall and other hydrometeorological variables. in many instances, drought indices are used for monitoring purposes. geostatistical methods allow the interpolation of spatially referenced data and the prediction of values...
In recent years due to increase of drought frequency, lakes water levels, in arid and semi-arid regions of the Iran, have dropped significantly. Therefore, in addition to ecosystem degradations, drought challenges socio-economic sectors as well. The purpose of this study was to evaluate the water level fluctuations of Parishan Lake during the wet and dry periods, and the impact of drought indic...
Abstract As the short- and long-term impacts of climate change are becoming more visible at smaller regional scales, frequent occurrence (absence) erratic precipitation as well water scarcity issues can be identified reliable indicators for predicting meteorological droughts. A supervised declaration drought based on available data requires an understanding reliability consistency indices appro...
چکیده خشکسالی بعنوان یک حادثه پیچیده که از وقوع یک یا چند دوره خشک بوجود میآید، اثرات زیانبار اقتصادی، اجتماعی و محیطی زیادی را در یک بازه کوتاه مدت بجا میگذارد. بررسی تغییرات مکانی خشکسالی با استفاده از شاخصهای مناسب میتواند به مدیریت صحیح خشکسالی در کشور کمک کند. در این پژوهش با استفاده از دادههای شدت خشکسالی حاصل شده از شاخصهای کوتاه مدت سه ماهه SPI، ZSI و PNI نقش...
To reduce the pressure on contacts and circuit breaker and realize the zone selective interlocking (ZSI) function above the instantaneous protection threshold (e.g., >10In), the short circuit current needs to be early detected. The state-of–art of early short circuit detection (ESCD) method is reviewed. Based on the equivalent model of the short circuit, a new method based on the current and it...
Abstract This paper presents a comparison between PV system using Z source inverters and Quazi Z source inverters. The Z-source inverter employs a unique LC network to couple the inverter power circuit to the diode front end and can be shoot through to boost the DC link voltage. By controlling the shoot-through duty cycle, the PV array output voltage is controlled and the maximum power point tr...
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