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Regional frequency analysis of drought severity and duration in Karkheh River Basin, Iran using univariate L-moments method

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ENVIRONMENTAL MONITORING AND ASSESSMENT 2022年第5期194卷 336-336页

作者： Parvizi, Saeideh Eslamian, Saeid Gheysari, Mahdi Gohari, Alireza Kopai, Saeid Soltani Isfahan Univ Technol Fac Agr Engn Water Engn Dept Esfahan *** Iran Isfahan Univ Technol Fac Nat Resources Dept Rangeland & Watershed Esfahan *** Iran

Drought is one of the natural disasters that causes a great damage to human life and natural ecosystems. The main differences are in the gradual effect of drought over a relatively long period, impossibility of accurately determining time of the beginning and end of drought, and geographical extent of the associated effects. On the other hand, lack of a universally accepted definition of drought has added to the complexity of this phenomenon. In the last decade, due to increasing frequency of drought in Iran and reduction of water resources, its consequences have become apparent and have caused problems for planners and managers. So in this research, regional frequency analysis using L-moments methods was performed to investigate severity and duration of Standardized Precipitation Index (SPI), Standardized Evapotranspiration Index (SEI), Standardized Runoff Index (SRI), and Standardized Soil Moisture Index (SSI) and to study of meteorological, agricultural, and hydrological droughts in Karkheh River Basin in Iran. Using K-means clustering method, basin was divided into four homogeneous areas. Uncoordinated stations in each cluster were removed. The best regional distribution function was selected for each homogeneous region, and it was found that Pearson type (3) has the highest fit on the data set in the basin. Based on Hosking and Wallis heterogeneity test, Karkheh Basin with H-1 < 1 was identified as acceptable homogeneous in all clusters. The results showed that hydrological drought occurs with a very short time delay in Karkheh River Basin after the meteorological drought, and two indicators show meteorological and hydrological drought conditions well. Agricultural drought occurs after meteorological and hydrological drought, respectively, and its severity and duration are less than the other indicators. Meteorological, hydrological, and agricultural droughts do not occur at the same time in all of the years. In general, the SPI drought index shows the most sev

关键词： K-means Clustering method Regional frequency analysis probability distribution function Growth curve Karkheh Basin L-moments Drought indices

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Game Theory——Optimum Strategy for Drawing Cards in 21Points

Game Theory——Optimum Strategy for Drawing Cards in 21Point...

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作者： Chenyiteng Han Ruoxun Peng Hengjie Zhao University of Toronto International Division The Second High School Attached to Beijing Normal University RDFZ Chaoyang Branch School

Blackjack is a popular casino poker game in which players make drawing decisions based on rules other than the size of their *** found that despite the randomness of the card draw,blackjack is actually very mathematical and *** calculating probabilities and using game theory,we can allow players to make relatively "rational" decisions that maximize their expectations of winning,rather than relying solely on guesswork and vague ***,in this article,we built several models to simulate a blackjack game with different numbers of *** players in each model,we give them a code that outputs the optimal decision,which helps them figure out the winning percentage(more specifically,the expectation,since once stakes are involved in multiplayer games,the winning percentage doesn't necessarily represent the expectation of winning money) for each decision,thus helping the player make a better decision.

关键词： Game Theory 21 points probability distribution function Payoff matrix

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Charging management of plug-in electric vehicles in San Francisco applying Monte Carlo Markov chain and stochastic model predictive control and considering renewables and drag force

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IET GENERATION TRANSMISSION & distribution 2020年第25期14卷 6179-6188页

作者： Rahmani-Andebili, Mehdi Bonamente, Massimiliano Miller, James A. SUNY Buffalo State Engn Technol Dept Buffalo NY 14222 USA Univ Alabama Dept Phys & Astron Huntsville AL 35899 USA

The charging management of plug-in electric vehicles (PEVs) in San Francisco considering the effect of drag force on the vehicles, the real driving routes of vehicles, the social aspects of drivers' behaviour, the type of PEVs and the PEV penetration level is presented in this study. In this study, the drivers' responsiveness probability, to provide vehicle-to-grid service at the parking lot, is modelled with respect to the value of the incentive, drivers' social class and the real driving routes in San Francisco. Herein, the Monte Carlo Markov Chain is applied to estimate the hourly probability distribution function of the state of charge (SOC) of the PEV fleet in the day. The main data set applied in this study includes the real longitude and latitude of driving routes of vehicles in San Francisco, recorded in every four-minute interval of the day. In this study, a stochastic model predictive control is applied in the optimisation problem to address the variability and uncertainty issues of PEVs' SOC and renewables' power. Herein, quantum-inspired simulated annealing algorithm is applied as the optimisation technique. It is demonstrated that the type of PEVs, the PEV penetration level and even the social class of drivers can affect the problem results.

关键词： stochastic processes simulated annealing battery powered vehicles Markov processes probability predictive control Monte Carlo methods electric vehicle charging vehicle-to-grid probability distribution function PEV fleet driving routes San Francisco stochastic model predictive control PEV penetration level charging management plug-in electric vehicles Monte Carlo Markov chain drag force vehicle-to-grid service PEV SOC quantum-inspired simulated annealing optimisation technique

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L-Histidine immobilized montmorillonite for As(III) adsorption and statistical verification of data by PDF, AICcorrected and AADR models

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APPLIED WATER SCIENCE 2022年第12期12卷 258-258页

作者： Batool, Aneeqa Shah, Khizar Hussain Hussain, Sajid Hussain, Zakir Naqvi, Syed Ali Raza Sherazi, Tauqir A. COMSATS Univ Islamabad Dept Chem Abbottabad Campus Abbottabad 22060 Pakistan COMSATS Univ Islamabad Dept Math Abbottabad Campus Abbottabad 22060 Pakistan Govt Coll Univ Dept Chem Faisalabad Pakistan

L-Histidine immobilized montmorillonite is prepared and used as an adsorbent for removal of As(III) from aqueous solutions. The L-Histidine immobilized montmorillonite is characterized by FTIR, XRD, TGA and PZC techniques that confirmed the successful insertion of Histidine into interlayer of montmorillonite structure. The various parameters such as pH, reaction time, temperature, concentration of As(III) and adsorbent dosage are optimized to obtain maximum As(III) adsorption. It is observed that usually the removal of As(III) is increased with increasing the amount of adsorbent, contact time, temperature and till pH 6. The results showed that all these adsorption parameters greatly influenced the adsorption process. The various adsorption isotherm models including Langmuir, Freundlich, Temkin and Dubinin-Radishkevich (DR) as well as kinetics models are applied to the adsorption data. The Langmuir isotherm and pseudo-second order kinetics model are well-fitted to the adsorption data. Further, the probability distribution function (PDF) is applied that verified the adsorption data well while the Akaike's Information Criterion (AIC(corrected)) and Absolute Average Relative Deviation (AARD) statistical models supported the best fit adsorption isotherms. The PDF model have provided a good statistical identification of adsorption parameters, adsorption rates and maxima whereas AIC(corrected) and AARD models revealed the well-fitting of Langmuir adsorption isotherm model in correlating the equilibrium data. Thermodynamic parameters (Delta H, Delta S, Delta G) proved the endothermic and spontaneous nature of adsorption process along with entropical changes occurring at solid-solution interface. The results showed that L-Histidine immobilized montmorillonite is an excellent material for As(III) adsorption with maximum adsorption capacity of 87.7 mg g(-1).

关键词： Montmorillonite L-Histidine As (III) Adsorption isotherm Kinetic models probability distribution function

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distribution of write error rate of spin-transfer-torque magnetoresistive random access memory caused by a distribution of junction parameters

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JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS 2022年 563卷

作者： Imamura, Hiroshi Arai, Hiroko Matsumoto, Rie Natl Inst Adv Ind Sci & Technol Tsukuba Ibaraki 3058568 Japan

distribution of write error rate (WER) of spin-transfer-torque magnetoresistive random access memory (STT MRAM) caused by a distribution of resistance area product and anisotropy constant is theoretically studied. Assuming that WER is much smaller than unity, and junction parameters obey a normal distribution, we show that the WER obeys a logarithmic normal distribution. We derive analytical expressions for the probability density function and statistical measures. We find that the coefficient of variation of WER can be reduced by decreasing the pulse width. We also perform numerical simulations based on the Fokker-Planck equation and confirm the validity of the analytical expressions. The results are useful for designing reliable STT MRAMs.

关键词： Spin transfer torque Magnetoresistive random access memory Write error rate probability distribution function Logarithmic normal distribution

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Propagation of a Fatigue Crack on the Surface of Side Frame of a Freight Bogie under Irregular Operating Loads

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MATERIALS SCIENCE 2020年第2期56卷 174-180页

作者： Rudavskyi, D., V Shefer, M. S. Kanyuk, Yu, I Ukrainian Natl Acad Sci Karpenko Physicomech Inst Lvov Ukraine

We study the kinetics of propagation of fatigue cracks on the surface of side frame of a rail car with regard for the stochastic nature of the operating load. Its dependence on the initial geometry of the crack is established. Moreover, under given loading conditions, we determine the shape of semielliptic contour of the fatigue crack characterized by the highest growth rate into the depth of the frame wall. We also formulate a mathematical model suitable for the evaluation of the residual service life of the side frame containing a surface cracklike defect with given initial area.

关键词： side frame fatigue crack stress intensity factor probability distribution function residual service life

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Toward Understanding the Differences of PM2.5Characteristics Among Five China Urban Cities

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ASIA-PACIFIC JOURNAL OF ATMOSPHERIC SCIENCES 2020年第4期56卷 493-502页

作者： Zhang, Kaiyang Zhao, Chuanfeng Fan, Hao Yang, Yikun Sun, Yue Beijing Normal Univ State Key Lab Earth Surface Proc & Resource Ecol Beijing 100875 Peoples R China Beijing Normal Univ Coll Global Change & Earth Syst Sci Beijing 100875 Peoples R China

Characteristics of PM(2.5)are investigated and compared based on observations from 2008 to 2017 in Beijing, Shenyang, Shanghai, Chengdu, and Guangzhou, which cover five different climate regions of China. Significant seasonal variations of PM(2.5)are found for all five cities, with the largest values in winter and the smallest in summer. The differences of PM(2.5)among the five cities are most likely associated with the emission sources, meteorology and topography. The strong emissions with surrounded mountains in Beijing make PM(2.5)high, particularly in winter. The basin topography surrounding by mountains in Chengdu makes the pollution hard to disperse and then causes high PM2.5. By contrast, the sea-land breeze helps disperse the air pollution in coastal cities such as Guangzhou and Shanghai by mixing and transport and makes PM(2.5)in those cites relatively low. Moreover, the population shows high values in Beijing and Shanghai, and the vehicle amount shows high values in Beijing and Chengdu, contributing to their high PM2.5. Similar monthly variations of PM(2.5)are found for the five cities, while the magnitude of variations are different. The five cities demonstrate more different diurnal variations of PM2.5. Associated with the sea-land breeze, there are very weak diurnal variations of PM(2.5)in Shanghai and Guangzhou. Differently, significant diurnal variations exist for Beijing, Shengyang and Chengu, with the minimum values in the afternoon and high values at night.

关键词： PM2 5 Urban aerosols China Seasonal variation probability distribution function Diurnal variation

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Climate change impacts on extreme rainfall frequency prediction

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JOURNAL OF WATER AND CLIMATE CHANGE 2020年第4期11卷 935-943页

作者： Alahmadi, Fahad S. Abd Rahman, Norhan Minist Environm Water & Agr Almadinah Almunawwarah Branch Almadinah Saudi Arabia Univ Teknol Malaysia Fac Civil Engn Dept Hydraul & Hydrol Skudai Campus Johor Bahru Johor 81310 Malaysia

The full integration between the computation of climate change effects and the prediction of extreme rainfall frequency is not yet well developed. In this study, the maximum daily rainfall of 26 stations in the western Kingdom of Saudi Arabia (KSA) are extracted covering an area of 180,000 km(2) for processing and analyzing. Discordancy test (D-i) showed that some stations are discordant, and the selected study area needs to be subdivided in order to reduce the inherent discordance. The rainfall stations are subdivided into three sub-regions based on a new approach by using L-Skewness parameter value (low, moderate, and high). Five probability distribution functions (PDFs) are evaluated using goodness of fit (Z(dist)) test and L-moment ratios diagram (LMRD). It was found that for sub-regions A, B, and C, the best fits are generalized Pareto (GPA), Pearson type III (PE3) and generalized extreme value (GEV) PDFs, respectively. Regional growth curves for each sub-region are developed and the predicted extreme rainfall for 100 years' return periods are computed for each station. Finally, climate change impact is evaluated using the emission scenario A2 which is about +40% and the predicted extreme rainfall frequency is computed taking into consideration the climate change impacts.

关键词： climate change L-moments probability distribution function regional frequency analysis Saudi Arabia

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Breakpoint detection in non-stationary runoff time series under uncertainty

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JOURNAL OF HYDROLOGY 2020年 590卷 125458-125458页

作者： Farsi, Niloofar Mahjouri, Najmeh Ghasemi, Hamid KN Toosi Univ Technol Fac Civil Engn Tehran Iran

Most conventional hydrological time series models, used for forecasting or synthetic data generation, are based on the stationary hypothesis. Hydrologic variables such as surface runoff discharge exhibit non-stationary behavior due to the effects of climate change or human activities. In this paper, a new methodology is proposed to analyze the uncertainty of the number and location of breakpoints in runoff time series. The non-stationary runoff time series is simulated by segmenting the series into stationary pieces, which follow an Auto-Regressive Moving Average (ARMA) process, based on the minimum description length (MDL) principle. The length of each piece and the order of the piecewise ARMA model are optimized using the Genetic Algorithm (GA). Several runoff time series with variable lengths are generated based on the observed data and the probability distribution function(s) (PDFs) of breakpoint location(s) are constructed. An optimal set of breakpoint locations are found for each generated runoff time series by minimizing the objective function based on the MDL. Finally, the PDF(s) of breakpoint location(s) is (are) constructed using the results of the mentioned optimization model. To evaluate the proposed methodology, it is applied to the case study of Zayandehrud River in Iran. According to the obtained breakpoint PDF for the runoff time series, three breakpoints around years of 1987, 1996 and 2006 are identified. The results are analyzed by investigating the time series of agricultural lands derived using remote sensing data and studying the impacts of interbasin water transfer projects implemented in the study area. Overall, investigating human-induced changes in the study area confirms the obtained shape of the PDF of runoff breakpoint and shows the good performance of the developed method for finding the number and location of breakpoints in the runoff time series.

关键词： Breakpoint Uncertainty Non-stationarity Runoff time series probability distribution function

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New adaptive histogram equalisation heuristic approach for contrast enhancement

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IET IMAGE PROCESSING 2020年第6期14卷 1110-1119页

作者： Kansal, Shubhi Tripathi, Rajiv Kumar Natl Inst Technol Elect & Commun Dept New Delhi India

Contrast enhancement of an image can be performed by using a simple histogram equalisation (HE) technique. However, there are some drawbacks of HE like immense brightness change, artificial effects, over-enhancement, which make it unsuitable to be used in many applications. To resolve these issues a new adaptive heuristic HE approach is proposed in this study. First, probability distribution function (PDF) of the image is calculated. Second, an adaptive parameter is calculated based on the mean and maximum values of that PDF. Thereafter, PDF and cumulative distribution function (CDF) are modified by applying a threshold limit to that adaptive parameter. Finally, another adaptive parameter is finding out by using modified CDF and a new CDF is obtained by using this second adaptive parameter. Traditional HE is then applied with the new CDF to getting the enhanced image. The visual and quantitative results of the proposed method outperform all other state-of-the-art papers and works well both for low and bright contrast images simultaneously. After rigorous experiment, it is concluded that the authors' method enhances the image contrast very well with no over-enhancement or artificial effects in the images and also preserves the original characteristics of the input images.

关键词： statistical distributions image enhancement adaptive parameter modified CDF low contrast images bright contrast images image contrast artificial effects input images new adaptive histogram equalisation heuristic approach contrast enhancement immense brightness change probability distribution function PDF cumulative distribution function simple histogram equalisation technique adaptive heuristic HE approach image enhancement

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