scholarly journals Wavelets based estimation of trend in sub-divisional rainfall in India

MAUSAM ◽  
2021 ◽  
Vol 71 (1) ◽  
pp. 69-78
Author(s):  
PAUL RANJIT KUMAR ◽  
SARKAR SANDIPAN ◽  
MITRA DIPANKAR ◽  
PANWAR SANJEEV ◽  
PAUL A K ◽  
...  
Keyword(s):  
Long Memory ◽  
Wavelet Transformation ◽  
Haar Wavelet ◽  
Recent Time ◽  
Monthly Rainfall ◽  
Discrete Wavelet ◽  
Wavelet Filter ◽  
Rainfall Trend ◽  
Trend Assessment ◽  
Non Parametric

Presence of long memory in climatic variables is frequently observed. The trend assessment becomes difficult in the presence of long-memory as the usual methods are not capable to take care of this property during trend estimation. In order to estimate the trend in presence of long memory, the non-parametric wavelet method has become popular in the recent time. The discrete wavelet transformation (DWT) re-expresses a time-series in terms of coefficients that are associated with a particular time and a particular scale. In the present study, DWT has been applied to estimate the monthly rainfall trend for the monsoon months: June-September in ten selected sub-divisions of India using “Haar” wavelet filter. The results from DWT were cross checked with the non-parametric Mann-Kendall (M-K) test. The investigation reveals that the monthly rainfall trend for the monsoon months of different sub-divisions in India are significantly decreasing over the years. However, in some of the sub-divisions, rainfall trend is increasing. DWT reveals significant trend in most of the sub-divisions whereas M-K test reveals that most of the trends are not significant at 5% level.

Trend assessment in a long memory dependence model using the discrete wavelet transform

2004 ◽  
Vol 15 (4) ◽  
pp. 313-335 ◽  
Author(s):  
Peter F. Craigmile ◽  
Peter Guttorp ◽  
Donald B. Percival
Keyword(s):  
Wavelet Transform ◽  
Discrete Wavelet Transform ◽  
Long Memory ◽  
Discrete Wavelet ◽  
Trend Assessment

scholarly journals Recent Trend of Precipitation and Crop Planning at Rajshahi Region of Bangladesh

2021 ◽  
pp. 28-39
Author(s):  
M. H. Ali ◽  
M. H. Zaman ◽  
M. A. Islam ◽  
P. Biswas ◽  
N. N. Karim ◽  
...  
Keyword(s):  
Recent Trend ◽  
Parametric Method ◽  
Monthly Rainfall ◽  
Agricultural Technology ◽  
Rainfall Trend ◽  
Cropping Patterns ◽  
Increasing Trend ◽  
Selection Of ◽  
Non Parametric

The study was carried out for investigation and analysis of long-term (45 years) monthly rainfall data of Rajshahi from 1975 to 2019 for better selection of crops and agricultural technology in this region of Bangladesh. The rainfall trend was determined using parametric and non-parametric method. Probability analysis of rainfall was performed for estimation of dry, wet, and average year rainfall. The results revealed negative trend of yearly rainfall, but it is statistically insignificant. By non-parametric method, ‘no trend’ was observed for yearly rainfall. Increasing trend of monthly rainfall during March and May and decreasing trend in other months were observed. The rainfall deficit period continued from November to March, and in some instant up to April (rainfall<PET).Total deficit for dry, wet, and average year were found as 488.2 mm, 405.7mm and 426.1mm respectively. By adopting low water-demanding cropping patterns during the deficit period, the withdrawal of groundwater can be minimized.

scholarly journals Comparative Compression of Wavelet Haar Transformation with Discrete Wavelet Transform on Colored Image Compression

2020 ◽  
Vol 3 (2) ◽  
pp. 202-209
Author(s):  
Christnatalis Christnatalis ◽  
Bachtiar Bachtiar ◽  
Rony Rony
Keyword(s):  
Wavelet Transform ◽  
Image Compression ◽  
Discrete Wavelet Transform ◽  
Wavelet Transforms ◽  
Wavelet Transformation ◽  
Haar Wavelet ◽  
Transformation Method ◽  
Discrete Wavelet ◽  
Digital Image Compression ◽  
The Right

In this research, the algorithm used to compress images is using the haar wavelet transformation method and the discrete wavelet transform algorithm. The image compression based on Wavelet Wavelet transform uses a calculation system with decomposition with row direction and decomposition with column direction. While discrete wavelet transform-based image compression, the size of the compressed image produced will be more optimal because some information that is not so useful, not so felt, and not so seen by humans will be eliminated so that humans still assume that the data can still be used even though it is compressed. The data used are data taken directly, so the test results are obtained that digital image compression based on Wavelet Wavelet Transformation gets a compression ratio of 41%, while the discrete wavelet transform reaches 29.5%. Based on research problems regarding the efficiency of storage media, it can be concluded that the right algorithm to choose is the Haar Wavelet transformation algorithm. To improve compression results it is recommended to use wavelet transforms other than haar, such as daubechies, symlets, and so on.

Evaluvation of Multiresolution Watermarking Algorithm

2017 ◽  
Vol 7 (8) ◽  
pp. 85
Author(s):  
S. Thabasu Kannan ◽  
S. Azhagu Senthil
Keyword(s):  
Digital Watermarking ◽  
Wavelet Transformation ◽  
Signal To Noise Ratio ◽  
Rapid Development ◽  
Threshold Value ◽  
Discrete Wavelet ◽  
Digital Production ◽  
Common Framework ◽  
Sampling Operation ◽  
Watermarking Scheme

Now-a-days watermarking plays a pivotal role in most of the industries for providing security to their own as well as hired or leased data. This paper its main aim is to study the multiresolution watermarking algorithms and also choosing the effective and efficient one for improving the resistance in data compression. Computational savings from such a multiresolution watermarking framework is obvious. The multiresolutional property makes our watermarking scheme robust to image/video down sampling operation by a power of two in either space or time. There is no common framework for multiresolutional digital watermarking of both images and video. A multiresolution watermarking based on the wavelet transformation is selected in each frequency band of the Discrete Wavelet Transform (DWT) domain and therefore it can resist the destruction of image processing.   The rapid development of Internet introduces a new set of challenging problems regarding security. One of the most significant problems is to prevent unauthorized copying of digital production from distribution. Digital watermarking has provided a powerful way to claim intellectual protection. We proposed an idea for enhancing the robustness of extracted watermarks. Watermark can be treated as a transmitted signal, while the destruction from attackers is regarded as a noisy distortion in channel.  For the implementation, we have used minimum nine coordinate positions. The watermarking algorithms to be taken for this study are Corvi algorithm and Wang algorithm. In all graph, we have plotted X axis as peak signal to noise ratio (PSNR) and y axis as Correlation with original watermark. The threshold value ά is set to 5. The result is smaller than the threshold value then it is feasible, otherwise it is not.

scholarly journals Universal statistical steganalytic method

2017 ◽  
Vol 68 (2) ◽  
pp. 117-124
Author(s):  
Martin Broda ◽  
Vladimír Hajduk ◽  
Dušan Levický
Keyword(s):  
Wavelet Transformation ◽  
Ensemble Classifier ◽  
Secret Message ◽  
Discrete Wavelet ◽  
Detection Accuracy ◽  
Discrete Cosine Transformation ◽  
Static Images ◽  
Novel Method ◽  
Statistical Steganalysis ◽  
Popular Image

Abstract Novel image steganalytic method used to detection of secret message in static images is introduced in this paper. This method is based on statistical steganalysis (SS), where statistical vector is composed by 285 statistical features (parameters) extracted from DCT (Discrete Cosine Transformation) domain and 46 features extracted mainly from DWT (Discrete Wavelet Transformation) domain. Classification process was realized by Ensemble classifier that was helpful in reduction of computational and time complexity. Proposed steganalytic method was verified by detection of popular image steganographic methods. Novel method was also compared with existing steganalytic methods by overall detection accuracy of a secret message.

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