scholarly journals Automatic Curve Extraction for Digitizing Rainfall Strip Charts

2011 ◽  
Vol 28 (7) ◽  
pp. 891-906 ◽  
Author(s):  
H. E. van Piggelen ◽  
T. Brandsma ◽  
H. Manders ◽  
J. F. Lichtenauer

Abstract A method has been developed that largely automates the labor-intensive extraction work for large amounts of rainfall strip charts and paper rolls. The method consists of the following five basic steps: 1) scanning the charts and rolls to high-resolution digital images, 2) manually and visually registering relevant meta information from charts and rolls and preprocessing rolls to locate day transitions, 3) applying automatic curve extraction software in a batch process to determine the coordinates of cumulative rainfall lines on the images, 4) postprocessing the curves that were not correctly determined in step 3, and 5) aggregating the cumulative rainfall in pixel coordinates to the desired time resolution. The core of the method is in step 3. Here a color detection procedure is introduced that automatically separates the background of the charts and rolls from the grid and subsequently the rainfall curve. The rainfall curve is detected by minimization of a cost function. In total, 321 station years of locations in the Netherlands have successfully been digitized and transformed to long-term rainfall time series with 5-min resolution. In about 30% of the cases, semiautomatic postprocessing of the results was needed using a purpose-built graphical interface application. This percentage, however, strongly depends on the quality of the recorded curves and the charts and rolls. Although developed for rainfall, the method can be applied to other elements as well.

Author(s):  
Neeta Baporikar

Due to pressures of globalization and competition, the quality of corporate leadership has come under great scrutiny as questions are being raised worldwide regarding the ability of leaders to deliver long term growth on a sustainable basis. This can be referred to as the “sustainability leadership cavity.” The chapter attempts to explore: what are the evolving challenges companies faces, what are the implications on demands placed on leaders and what new leadership competencies are required to ensure sustainability goals are achieved. It also intends to provide cases of successful sustainability leadership. Through grounded theory, in-depth literature review and contextual analysis the core of this chapter is to understand the organizational elements, structure, challenges and competencies crucial and critical for sustainability leadership.


Author(s):  
Liudmyla VOLONTYR

Development of modern economic trends in the system of conceptual foundations for the improvements in sugar beet production sector has necessitated the introduction of new approaches in the processes of managing commodity, financial and information flows on the basis of the use of methods of economic and mathematical modeling. The main idea for implementation these methods is to evaluate the development of forecasts in terms of their formalization, systematization, optimization and adaptation under application of new information technologies. The quality of management decision-making depends on the accuracy and reliability of the developed long-term evaluations. In this regard, one of the most important areas of research in the economy is to forecast the parameters of the beet industry development and to obtain predictive decisions that form the basis for effective activity in the process of achieving tactical and strategic goals. Under a significant dispersion of the time series levels, a variety of smoothing procedures are used to detect and distinguish the trend: direct level equalization by the ordinary least squares technique, ordinary and weighted moving averages, exponential smoothing, spectral methods and application of splines, moving average method, or running median smoothing. The most common among them are regular and weighted moving averages and exponential smoothing. Investigation of methods of forecasting parameters of development of beet growing industry taking into account the peculiarities of constructing quantitative and qualitative forecasts requires solving the following tasks: - investigation of the specifics of the use of statistical methods of time series analysis in beet growing; - research of the specificity of the use of forecasting methods for the estimation of long-term solutions in beet growing; - carrying out practical implementation of the methods as exemplified by the estimation of forecasts of sugar beet yields at the enterprises of Ukraine. The method of exponential smoothing proposed by R. G. Brown gives the most accurate approximation to the original statistical series – it takes into account the variation of prices. The essence of this method lies in the fact that the statistical series is smoothed out with the help of a weighted moving average, which is subject to the exponential law. When calculating the exponential value of time t it is always necessary to have the exponential value at the previous moment of time, and therefore the first step is to determine some Sn-1 value that precedes Sn. In practice, there is no single approach to defining initial approximations – they are set in accordance with the conditions of economic research. Quite often, the arithmetic mean of all levels of the statistical series is used as Sn-1. It should be noted that a certain problem in forecasting with the help of exponential smoothing is the choice of the parameter a optimal value, on which the accuracy of the results of the forecast depends to a large extent. If the parameter a is close to the identity element, then the forecast model takes into account only the effects of the last observations, and if it approaches to zero, then almost all the previous observations are usually taken into account. However, scientific and methodical approaches to determining the optimal value of the smoothing parameter have not yet been developed. In practice, the value of a is chosen according to the smallest dispersion of deviations of the predicted values of the statistical series from its actual levels. The method of exponential smoothing gives positive findings when a statistical series consists of a large number of observations and it is assumed that the socioeconomic processes in the forecasting period will occur approximately under the same conditions as in the base period. A correctly selected model of the growth curve shall correspond to the nature of the trend change of the phenomenon under study. The procedure for developing a forecast using growth curves involves the following steps: - choice of one or several curves whose shape corresponds to the nature; - time series changes; - evaluation of the parameters of the selected curves; - verification of the adequacy of the selected curves of the process being foreseen; - evaluation of the accuracy of models and the final choice of the growth curve; - calculation of point and interval forecasts. The most common practice in forecasting are the functions used to describe processes with a monotonous nature of the trend of development and the absence of growth boundaries. On the basis of the studied models, smoothing of the statistical series of the sugar beet gross yields of in Ukraine was carried out. The statistical data from 1990 to 2017 have been taken for the survey. The forecast of the sugar beet yields for 2012-2017 have been used to determine the approximation error by the ordinary moving averages with a length of the smoothing interval of 5 years and 12 years, as well as by the method of exponential smoothing with the parameter α = 0,3 and α = 0, 7 The analysis of the quality of forecasts is based on the average absolute deviation. Therefore, this value is the smallest for the forecast, which is determined by the method of exponential smoothing with the constant value of a = 0,7. By this method, we will determine the forecast for the next 5 years.


Author(s):  
E. Fakiris ◽  
D. Zoura ◽  
K. Katsanou ◽  
P. Kriempardi ◽  
N. Lambrakis ◽  
...  

Author(s):  
O. M. Zhitinskaya ◽  
L. A. Yarg

The influence of the processes of functioning of the local natural-technical systems (NTS) «Stoilenskoe» and «Lebedinskoe» of the KMA deposit on the environment has been studied with the information obtained during the period of last 7—12 years (2004—2015 y.y.). Results of the analyses of time series and obtained trends in the geological components alteration (in particular, a) level of groundwater, b) chemical composition of groundwater, c) engineering and geological processes) have been given. The ways of regime observations optimization concerning their placement and frequency in time have been offered. The proposed way of the assessment of the current state of NTS allows reducing the observations number, without reducing quality of information. The spatial structure and the time mode of monitoring have to be corrected according to the obtained information. The data received from Lebedinskoye and Stoylinskoye fields can be used for design and development of the similar geological fields.


2008 ◽  
Vol 47 (4) ◽  
pp. 1006-1016 ◽  
Author(s):  
Guang-Yu Shi ◽  
Tadahiro Hayasaka ◽  
Atsumu Ohmura ◽  
Zhi-Hua Chen ◽  
Biao Wang ◽  
...  

Abstract Solar radiation is one of the most important factors affecting climate and the environment. Routine measurements of irradiance are valuable for climate change research because of long time series and areal coverage. In this study, a set of quality assessment (QA) algorithms is used to test the quality of daily solar global, direct, and diffuse radiation measurements taken at 122 observatories in China during 1957–2000. The QA algorithms include a physical threshold test (QA1), a global radiation sunshine duration test (QA2), and a standard deviation test applied to time series of annually averaged solar global radiation (QA3). The results show that the percentages of global, direct, and diffuse solar radiation data that fail to pass QA1 are 3.07%, 0.01%, and 2.52%, respectively; the percentages of global solar radiation data that fail to pass the QA2 and QA3 are 0.77% and 0.49%, respectively. The method implemented by the Global Energy Balance Archive is also applied to check the data quality of solar radiation in China. Of the 84 stations with a time series longer that 20 yr, suspect data at 35 of the sites were found. Based on data that passed the QA tests, trends in ground solar radiation and the effect of the data quality assessment on the trends are analyzed. There is a decrease in ground solar global and direct radiation in China over the years under study. Although the quality assessment process has significant effects on the data from individual stations and/or time periods, it does not affect the long-term trends in the data.


MAUSAM ◽  
2021 ◽  
Vol 71 (2) ◽  
pp. 209-224
Author(s):  
RAJANI NIRAV V ◽  
TIWARI MUKESH K ◽  
CHINCHORKAR S S

Trend analysis has become one of the most important issues in hydro-meteorological variables study due to climate change and the focus given to it in the recent past from the scientific community. In this study, long-term trends of rainfall are analyzed in eight stations located in semi-arid central Gujarat region, India by considering time series data of 116 years (1901-2016). Discrete wavelet transform (DWT) as a dyadic arrangement of continuous wavelet transformation combined with the widely applied and acknowledged Mann-Kendall (MK) trend analysis method were applied for analysis of trend and dominant periodicities in rainfall time series at monthly, annual and monsoonal time scales. Initially, rainfall time series applied in this study were decomposed using DWT to generate sub-time series at high and low frequencies, before applying the MK trend test. Further, the Sequential Mann-Kendall (SQMK) test was also applied to find out the trend changing points. The result showed that at the monthly annual and monsoon time scales, the trends in rainfall were significantly decreasing in most of the station. The 4-month and 8-month components were found as dominant at the monthly time series and the 2-year and 4-year component were found as dominant at the monsoon time series, whereas the 2-year components were observed as dominant in the annual time scale.


2021 ◽  
Vol 3 (2) ◽  
pp. e000218
Author(s):  
Arjune Sen ◽  
Ryan Verner ◽  
James P Valeriano ◽  
Ricky Lee ◽  
Muhammad Zafar ◽  
...  

IntroductionThe Vagus Nerve Stimulation Therapy System (VNS Therapy) is an adjunctive neuromodulatory therapy that can be efficacious in reducing the frequency and severity of seizures in people with drug-resistant epilepsy (DRE). CORE-VNS aims to examine the long-term safety and clinical outcomes of VNS in people with DRE.Methods and analysisThe CORE-VNS study is an international, multicentre, prospective, observational, all-comers, post-market registry. People with DRE receiving VNS Therapy for the first time as well as people being reimplanted with VNS Therapy are eligible. Participants have a baseline visit (prior to device implant). They will be followed for a minimum of 36 months and a maximum of 60 months after implant. Analysis endpoints include seizure frequency (average number of events per month), seizure severity (individual-rated categorical outcome including very mild, mild, moderate, severe or very severe) as well as non-seizure outcomes such as adverse events, use of antiseizure medications, use of other non-pharmacological therapies, quality of life, validated measures of quality of sleep (Pittsburgh Sleep Quality Index or Children’s Sleep Habit Questionnaire) and healthcare resource utilisation. While the CORE-VNS registry was not expressly designed to test hypotheses, subgroup analyses and exploratory analysis that require hypothesis testing will be conducted across propensity score matched treatment groups, where possible based on sampling.Ethics and disseminationThe CORE-VNS registry has already enrolled 823 participants from 61 centres across 15 countries. Once complete, CORE-VNS will represent one of the largest real-world clinical data sets to allow a more comprehensive understanding of the management of DRE with adjunctive VNS. Manuscripts derived from this database will shed important new light on the characteristics of people receiving VNS Therapy; the practical use of VNS across different countries, and factors influencing long-term response.Trail registration numberNCT03529045.


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