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An efficient algorithm to clip a 2D-polygon against a rectangular clip window

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Applied Mathematics(A Journal of Chinese Universities) 2022年第1期37卷 147-158页

作者： Sushil Chandra Dimri Umesh kumar tiwari Mangey ram Department of Computer Science and Engineering Graphic Era(Deemed to be University)DehradunUttarakhandIndia

Polygon clipping is of great importance in computer *** of the popular algorithms to clip a polygon is Cohan–Sutherland Hodgeman algorithm which is based on line ***–Sutherland Hodgeman algorithm clips the polygon against the given rectangular clip window with the help of line clipping ***–Sutherland algorithm requires traversing the polygon in anti clockwise direction(positive orientation).In this work we propose an efficient polygon clipping algorithm against a rectangular clip *** algorithm uses parametric representation of polygon *** the concept of point clipping,we can find required intersection points of edges of polygon with clip window *** suited numerical illustrations are used to explain the proposed polygon clipping *** proposed algorithm is computationally less expensive and comprehensive.

关键词： point clipping polygon clipping clip window line segment computational complexity

维普期刊数据库

Dorsal-Ventral Visual Pathways and Object Characteristics:Beamformer Source Analysis of EEG

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Computers, Materials & Continua 2022年第2期70卷 2347-2363页

作者： Akanksha tiwari ram Bilas Pachori Premjit khanganba Sanjram Department of Biosciences and Biomedical Engineering Indian Institute of Technology IndoreIndore453552India Department of Electrical Engineering Indian Institute of Technology IndoreIndore453552India Discipline of Psychology Indian Institute of Technology IndoreIndore453552India Center for Electric Vehicles and Intelligent Transport Systems Indian Institute of Technology IndoreIndore453552India

In performing a gaming task,mental rotation(MR)is one of the important aspects of visuospatial *** involves dorsal-ventral pathways of the *** objects/models used in computer-games play a crucial role in gaming experience of the *** visuospatial characteristics of the objects used in the computer-game influence the engagement of dorsal-ventral visual *** current study investigates how the objects’visuospatial characteristics(i.e.,angular disparity and dimensionality)in an MR-based computer-game influence the cortical activities in dorsalventral visual *** the factors have two levels,angular disparity:convex angle(CA)*** angle(RA)and dimensionality:2D *** healthy adults,aged,18-29 years(M=21.6)were recruited for the study and randomly assigned to four gaming conditions i.e.,15 participants in each *** multichannel electroencephalogram(EEG)data were recorded from 60 healthy adults while playing the *** source reconstruction was done for∼3000 sources inside the brain using the Dynamic Imaging of Coherent Sources(DICS)beamforming method forθ1(4-5.75),θ2(5.75-7.5),α1(7.5-9),α2(9-11),α3(11-13),β1(13-17.25),β2(17.25-21.5)Hz frequency *** reconstructed neuronal sources were segmented into 68 functionally parcellated brain regions,and the percentage of active sources for each region was ***,the differences across the 68 regions among the four gaming conditions were evaluated using the percentage of active *** differences in activation for the dorsal-ventral pathways and some additional brain regions were observed among the four *** game with 2D objects and CA showed higher activation than that with 3D objects and RA,*** dorsal pathway was found to be more active in contrast to the ventral *** findings suggest that angular disparity and dimensionality in MR influence the engagement of dorsal-ventral visual pathways in such a way that angular disparit

关键词： Mental rotation EEG source localization DICS beamformer dorsal-ventral pathway

Dimensionality and Angular Disparity Influence Mental Rotation in Computer Gaming

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Computers, Materials & Continua 2022年第7期72卷 887-905页

Computer gaming is one of the most common activities that individuals are indulged in their usual activities concerning interactive systembased *** processing is an essential aspect of mental rotation(MR)in playing *** studies have explored how objects’features affect theMRprocess;however,non-isomorphic 2Dand 3D objects lack a fair *** addition,the effects of these features on brain activation during the MR in computer-games have been less *** study investigates how dimensionality and angular disparity affect brain activation duringMRin ***(electroencephalogram)data were recorded from sixty healthy adults while playing an MR-based computer *** 2D and 3D visual objects with convex and reflex angular disparity were presented in the ***-based permutation tests were applied on EEG spectral power for frequency range 3.5–30 Hz to identify significant spatio-spectral ***,the band-specific hemispheric lateralization was evaluated to investigate task-specific *** results indicated higher alpha desynchronization in the left hemisphere during MR compared to *** fronto-parietal areas showed neural activations during the game with convex angular disparities and 3D objects,for a frequency range of 7.8–14.2Hz and 7.8–10.5Hz,*** areas also showed activations during the game with reflex angular disparities and 2D objects,but for narrower frequency bands,i.e.,8.0–10.0 Hz and 11.0–11.7 Hz,*** hemispheric dominance was observed for alpha and beta ***,the right parietal region was notably more dominant for convex angular disparity and 3D ***,the results showed higher neural activities elicited by convex angular disparities and 3D objects in the game compared to the reflex angles and *** findings suggest future applications,such as cognitive modeling and controlled MR training using computer g

关键词： Computer-based games angular disparity dimensionality mental rotation EEG hemispheric laterality

Isomorphic 2D/3D Objects and Saccadic Characteristics in Mental Rotation

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Computers, Materials & Continua 2022年第1期70卷 433-450页

Mental rotation(MR)is an important aspect of cognitive processing in gaming since transformation andmanipulation of visuospatial information are necessary in order to execute a gaming *** study provides insights on saccadic characteristics in gaming task performance that involves 2D and 3D isomorphic objects with varying angular *** participants(N=60)performedMR gaming *** participantwas tested individually in an acoustic treated lab *** behavior data of all participants were recorded during task execution and analyzed to find the changes in spatiotemporal characteristics of saccades associated with the variation in angular disparity and *** were four groups with unique combination of angular disparity and dimensionality,each with fifteen participants randomly *** indicate that the spatial characteristics of the object affect the temporal aspect of saccade(duration),whereas the spatial aspect of the saccade(amplitude)is influenced by the objects’dimension.A longer saccade duration indicates a prolonged suppression of spatial information processing during the MR tasks with objects at convex range angular ***,the MR tasks with convex angular disparity become more complex to process compared to the tasks with reflex angular *** process is faster and more accurate with 3D objects compared to the 2D *** is an interaction between angular disparity and dimensionality in terms of mental demand,such that theMR processing with 2Dobjects in reflex angular disparitywasmoremental demanding than that of convex angular disparity;however,this trend was absent in case of ***,during the MR task,the longer saccade duration implies that the taskswith convex angular disparities become comparativelymore ***,the lower saccadic amplitude for 2D objects indicates difficulties in processing due to deficient visual *** findings could help in framing the c

关键词： Mental rotation computer-game angular disparity dimensionality gaze behavior

Gorkha earthquake (MW7.8) and aftershock sequence: A fractal approach

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Earthquake Science 2022年第3期35卷 193-204页

作者： ram k.ishna tiwari Harihar Paudyal Central Department of Physics Tribhuvan UniversityKirtipurKathmandu 44618Nepal Birendra Multiple Campus Tribhuvan UniversityBharatpurChitwan 44200Nepal

On April 25, 2015, Nepal was struck by the MW7.8 Gorkha earthquake followed by an intense aftershock sequence. It was one of the most destructive earthquakes in the Himalayan arc, causing more than 8900 fatalities. In this study, we analyzed the dataset (429 events, magnitude of completeness (Mc) ≥ 4.2 local magnitude) of the first 45 days after the Gorkha earthquake to estimate the seismicity parameters b-value, D-value, and p-value. We used the maximum likelihood method to estimate the b-value and Omori-Utsu parameters, whereas the correlation integral method was applied to estimate the fractal dimension (D-value). The analysis was carried out using running and sliding window techniques. The lowest b-value (0.57 ± 0.04) and the highest D-value (1.65 ± 0.02) were computed at the time of the Gorkha earthquake, after which the b-value significantly increased to a maximum of 1.57. It again dropped to 0.93 at the time of the major aftershock on May 12, 2015. The D-value showed an initial quick drop and then decreased in a wavy pattern until the end of the study period, indicating the clustering and scattering of earthquakes in a fault region. The b-value contour map identified the eastern part of the study area as a high stress region (b = ~0.8), implying that the stress shifted to that region. The D-value contour map reveals that the seismogenic structure shifted from linear to planar in the region. The rate of aftershock decay (p = 0.86 ± 0.04) for a short period reflects that the level of stress decreased rapidly. This study helps to understand the level of stress and seismicity pattern of a region, which could be useful for aftershock studies.

关键词： Omori-Utsu law correlation integral fractal dimension b-value central Himalaya

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喜马拉雅东段及其周边地区地震b值和分形维数时空分布特征

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Applied Geophysics 2022年第3期19卷 458-469,472页

基于1964—2020年1373次地震(Mc=4.0),采用滑动窗口方法对喜马拉雅山脉东段及其周边地区(26°N–31°N和87°E–98°E)地震b值和分形维数时空特征进行分析。论文将研究区划分为3个子区,即A区(87°E–92°E),B区(92°E–94°E)和C区(94°... 详细信息

基于1964—2020年1373次地震(Mc=4.0),采用滑动窗口方法对喜马拉雅山脉东段及其周边地区(26°N–31°N和87°E–98°E)地震b值和分形维数时空特征进行分析。论文将研究区划分为3个子区,即A区(87°E–92°E),B区(92°E–94°E)和C区(94°E–98°E)。在A区包括尼泊尔东部,b值要高于其他区域,说明该区域可能存在高应力集聚和凹凸体。同时,A区地震具有高空间(Dc>1.5)和低时间分形维数(Dt<0.31),说明地震孕育断层接近于2维结构,且震中具有群聚群发特征。A区、C区地震b值与空间分形维度弱负相关,两者在B区则呈弱正相关。基于b值和分形维数,论文解释了喜马拉雅山脉东段孕震结构的时空变化的特征,可为理解区域强震发生规律提供理论基础。

关键词：喜马拉雅山脉东段断层 b值分形维度地震聚类

Investigation of tuberculosis clusters in Dehradun city of India

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Asian Pacific Journal of Tropical Medicine 2010年第6期3卷 486-490页

作者： Neeraj tiwari Vineeta kandpal Ajoy Tewari k.ram Mohan Rao Tolia VS Department of Statistics Kumaun UniversitySSJ CampusAlmora-263601India Department of Anatomy ERA's Medical CollegeLucknow-226001India Jai Clinic & Diabetes Care Centre Lucknow-226001India Geoinformatics Division Indian Institute of Remote SensingDehradun-248001India District Tuberculosis Officer Dehradun 248001India

Objective:To investigate the presence of statistically significant geographical clusters of tuberculosis(TB) using Geographical Information System and spatial scan statistics in Dehradun, ***:The spatial scan statistic implemented with a software program,SaTScan v6.1, was used to test the presence of statistically significant spatial clusters of TB and to identify their approximate locations(P<0.05 for primary clusters and P<0.1 for secondary clusters). Geographical Information System was used for geographical ***:Significant high rate spatial clusters were identified in seven wards of the Dehradun Municipal area. Conclusions:There is sufficient evidence about the existence of statistically significant TB clusters in seven wards of Dehradun,*** purely spatial scan statistics methodology used in this study has a potential use in surveillance of TB for detecting the true clusters of the disease.

关键词： Geographical Information System Mycobacterium tuberculosis Spatial scan statistics TB/HIV

喜马拉雅东段及其周边地区地震b值和分形维数时空分布特征（英文）

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Applied Geophysics 2022年第3期 458-469+472页

作者： ram k.ishna tiwari Harihar Paudyal Daya Shanker Central Department of Physics Tribhuvan University Birendra Multiple Campus Tribhuvan University Department of Earthquake Engineering Indian Institute of Technology Roorkee

基于1964—2020年1373次地震(Mc=4.0)，采用滑动窗口方法对喜马拉雅山脉东段及其周边地区(26°N–31°N和87°E–98°E)地震b值和分形维数时空特征进行分析。论文将研究区划分为3个子区，即A区(87°E–92°E), B区(92°E–94°E)和C区(9... 详细信息

基于1964—2020年1373次地震(Mc=4.0)，采用滑动窗口方法对喜马拉雅山脉东段及其周边地区(26°N–31°N和87°E–98°E)地震b值和分形维数时空特征进行分析。论文将研究区划分为3个子区，即A区(87°E–92°E), B区(92°E–94°E)和C区(94°E–98°E)。在A区包括尼泊尔东部，b值要高于其他区域，说明该区域可能存在高应力集聚和凹凸体。同时，A区地震具有高空间(Dc>1.5)和低时间分形维数(Dt<0.31)，说明地震孕育断层接近于2维结构，且震中具有群聚群发特征。A区、C区地震b值与空间分形维度弱负相关，两者在B区则呈弱正相关。基于b值和分形维数，论文解释了喜马拉雅山脉东段孕震结构的时空变化的特征，可为理解区域强震发生规律提供理论基础。

关键词：喜马拉雅山脉东段断层 b值分形维度地震聚类

Solution of Electrohydrodynamic Flow Equation Using an Orthogonal Collocation Method Based on Mixed Interpolation

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Journal of Applied Mathematics and Physics 2018年第3期6卷 573-587页

作者： Shruti tiwari ram k. Pandey Department of Mathematics and Statistics Dr. H.S. Gour Vishwavidyalaya Sagar India

In this Paper, we have proposed a new weighted residual method known as orthogonal collocation-based on mixed interpolation (OCMI). Mixed interpolation uses the classical polynomial approximation with two correction terms given in the form of sine and cosine function. By these correction terms, we can control the error in the solution. We have applied this approach to a non-linear boundary value problem (BVP) in ODE which governs the electrohydrodynamic flow in a cylindrical conduit. The solution profiles shown in the figures are in good agreement with the work of Paullet (1999) and Ghasemi et al. (2014). Our solution is monotonic decreasing and satisfies , where, α governs the strength of non-linearity and for large values of α solutions are . The residual errors are given in Table 1 and Table 2 which are significantly small. Comparison of residual errors between our proposed method, Least square method and Homotopy analysis method is also given and shown via the Table 3 where as the profiles of the residual error are depicted in Figures 4-8. Table and graphs show that efficiency of the proposed method. The error bound and its L2-norm with relevant theorems for mixed interpolation are also given.

关键词： Electrohydrodynamic (EHD) Flow Weighted Residual Method Orthogonal Polynomial Mixed Interpolation