Evaluating the Performance of Multi-Class and Single-Class Classification Approaches for Mountain Agriculture Extraction Using Time-Series NDVI     

Saptarshi Mondal  Chockalingam Jeganathan 《Journal of the Indian Society of Remote Sensing》2018,46(12):2045-2055

Supervised multi-class classification (MCC) approach is widely being used for regional-level land use–land cover (LULC) mapping and monitoring. However, it becomes inefficient if the end user wants to map only one particular class. Therefore, an improved single-class classification (SCC) approach is required for quick and reliable map production purpose. In this regard, the current study attempts to evaluate the performance of MCC and SCC approaches for extracting mountain agriculture area using time-series normalized differential vegetation index (NDVI). At first, samples of eight LULC classes were acquired using Google Earth image, and corresponding temporal signatures (TS) were extracted from time-series NDVI to perform classification using minimum distance to mean (MDM) and spectral angle mapper (i.e., multi-class SAM—MCSAM) under MCC approach. Secondly, under SCC approach, the TS of three agriculture classes (i.e., agriculture, mixed agriculture and plantation) were utilized as a reference to extract agriculture extent using Euclidean distance (ED) and SAM (i.e., single-class SAM—SCSAM) algorithms. The area of all four maps (i.e., MDM—19.77% of total geographical area (TGA), MCSAM—21.07% of TGA, ED—15.23% of TGA, SCSAM—13.85% of TGA) was compared with reference agriculture area (14.54% of TGA) of global land cover product, and SCC-based maps were found to have close agreement. Also, the class-wise detection accuracy was evaluated using random sample point-based error matrix which reveals the better performance of ED-based map than rest three maps in terms of overall accuracy and kappa coefficient.  相似文献   

The analysis of unparalleled struggle for existence of urban women informal workers in West Bengal,India for survival and resilience to COVID-19 pandemic risk     

Mondal  Manishree  Chakraborty  Chayon 《GeoJournal》2022,87(4):607-630

An unparalleled struggle has been witnessed among the urban women informal workers of Midnapore and Kharagpur cities in West Bengal, India. Many researchers have advocated and are advocating about the deadly impact of COVID-19 pandemic situation on the women informal workers but very few were concentrated on their coping capabilities. These women in the study area have set an example before others that how can one survive her livelihood in the time of critical situation. Despite all the hardships they have been fighting their own lonely battle not only against this situation but also a lot of serious threats like insecurity, low resources and low standard of living. This study mainly highlights the measures taken by these poor women to cope with this situation for the survival of their families along with the external supports provided for them. This is strictly a perception based study conducted among 500 women selected by purposive sampling procedure across age, ethnicity, income and educational level during unlock phases with the help of semi-structured and open ended questionnaire schedule. The result reveals that although their capabilities and efforts to cope with this devastating situation are praiseworthy but it is a hard reality that this pandemic put its evil imprint in every step of their daily livelihoods. The various measures have already been taken by the government but, these measures have to be continued till the situation will become normal along with gender sensitive long term benefit.

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Effects of vertical irregularity and thickness of unreinforced masonry infill on the robustness of RC framed buildings          下载免费PDF全文

Goutam Mondal  Solomon Tesfamariam 《地震工程与结构动力学》2014,43(2):205-223

Presence of irregularities in reinforced concrete (RC) buildings increases seismic vulnerability. During severe seismic shaking, such buildings may suffer disproportionate damage or even collapse that can be minimized by increasing robustness. Robustness is a desirable property of structural systems that can mitigate susceptible buildings to disproportionate collapse. In this paper, the effects of vertical irregularity and thickness of unreinforced masonry infill on the robustness of a six‐story three‐bay RC frame are quantified. Nonlinear static analysis of the frame is performed, and parametric study is undertaken by considering two parameters: absence of masonry infill at different floors (i.e., vertical irregularities) and infill thickness. Robustness has been quantified in terms of stiffness, base shear, ductility, and energy dissipation capacity of the frame. It was observed that the infill thickness and vertical irregularity have significant influence on the response of RC frame. The response surface method is used to develop a predictive equation for robustness as a function of the two parameters. The predictive equation is validated further using 12 randomly selected computer simulations. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Gravitational wave emission from a companion black hole in the presence of an accretion disc around a super-massive Kerr black hole     

Prasad Basu  S. Mondal  Sandip K. Chakrabarti 《Monthly notices of the Royal Astronomical Society》2008,388(1):219-226

Gravitational wave signal characteristics from a binary black hole system in which the companion moves through the accretion disc of the primary are studied. We chose the primary to be a super-massive  ( M = 10⁸ M_⊙)  Kerr black hole and the companion to be a massive black hole  ( M = 10⁵ M_⊙)  to clearly demonstrate the effects. We show that the drag exerted on the companion by the disc is sufficient to reduce the coalescence time of the binary. The drag is primarily due to the fact that the accretion disc on a black hole deviates from a Keplerian disc and becomes sub-Keplerian due to inner boundary condition on the black hole horizon. We consider two types of accretion rates on to the companion. The companion is deeply immersed inside the disc and it can accrete at the Bondi rate which depends on the instantaneous density of the disc. However, an accretion disc can also form around the smaller black hole and it can accrete at its Eddington rate. Thus, this case is also studied and the results are compared. We find that the effect of the disc will be significant in reducing the coalescence time and one needs to incorporate this while interpreting gravitational wave signals emitted from such a binary system.  相似文献   

Modeling of the Removal of Arsenic Species from Simulated Groundwater Containing As,Fe, and Mn: A Neural Network Based Approach     

Prasenjit Mondal  Bikash Mohanty  Chandrajit Balomajumder  Samir Saraswati 《洁净——土壤、空气、水》2012,40(3):285-289

The present paper deals with the modeling of the removal of total arsenic As(T), trivalent arsenic As(III), and pentavalent arsenic As(V) from synthetic solutions containing total arsenic (0.167–2.0 mg/L), Fe (0.9–2.7 mg/L), and Mn (0.2–0.6 mg/L) in a batch reactor using Fe impregnated granular activated charcoal (GAC‐Fe). Mass ratio of As(III) and As(V) in the solution was 1:1. Multi‐layer neural network (MLNN) has been used and full factorial design technique has been applied for the selection of input data set. The developed models are able to predict the adsorption of arsenic species with an error limit of ?0.3 to +1.7%. Combination of MLNN with design of experiment has been able to generalize the MLNN with less number of experimental points.  相似文献   

Uncertainty of soil erosion modelling using open source high resolution and aggregated DEMs     

Arun Mondal  Deepak Khare  Sananda Kundu  Sandip Mukherjee  Anirban Mukhopadhyay  Surajit Mondal 《地学前缘(英文版)》2017,8(3):425-436

Digital Elevation Model (DEM) is one of the important parameters for soil erosion assessment. Notable uncertainties are observed in this study while using three high resolution open source DEMs. The Revised Universal Soil Loss Equation (RUSLE) model has been applied to analysis the assessment of soil erosion uncertainty using open source DEMs (SRTM, ASTER and CARTOSAT) and their increasing grid space (pixel size) from the actual. The study area is a part of the Narmada river basin in Madhya Pradesh state, which is located in the central part of India and the area covered 20,558 km². The actual resolution of DEMs is 30 m and their increasing grid spaces are taken as 90, 150, 210, 270 and 330 m for this study. Vertical accuracy of DEMs has been assessed using actual heights of the sample points that have been taken considering planimetric survey based map (toposheet). Elevations of DEMs are converted to the same vertical datum from WGS 84 to MSL (Mean Sea Level), before the accuracy assessment and modelling. Results indicate that the accuracy of the SRTM DEM with the RMSE of 13.31, 14.51, and 18.19 m in 30, 150 and 330 m resolution respectively, is better than the ASTER and the CARTOSAT DEMs. When the grid space of the DEMs increases, the accuracy of the elevation and calculated soil erosion decreases. This study presents a potential uncertainty introduced by open source high resolution DEMs in the accuracy of the soil erosion assessment models. The research provides an analysis of errors in selecting DEMs using the original and increased grid space for soil erosion modelling.  相似文献   

Natural zeolites enhance groundwater quality: evidences from Deccan basalts in India     

E. Nagaiah  S. Sonkamble  N. C. Mondal  S. Ahmed 《Environmental Earth Sciences》2017,76(15):536

The zeolite minerals characterized with hydrated aluminosilicates, negative ionic charge and 3D framework structure are well known for purifying the groundwater occurring in basaltic aquifer systems. However, the filtering mechanism at in situ field conditions is a complex process, which is rarely studied, and hence, it needs to be demonstrated. This paper explores the mechanism of hydrochemical processes and evolution of natural zeolites associated with basaltic rock to enhance groundwater quality. We present the hydrochemical findings and evolution processes derived from 46 groundwater samples (N_t = 46) belong to zeolitic (N_z = 25) and non-zeolitic (N_nz = 21) zones of a micro-watershed (4.4 km²) beset over basaltic terrain, Deccan Volcanic Province (DVP), India. The groundwater samples collected for one hydrological cycle (pre- and post-monsoons) are examined for major ion chemistry to determine the aqueous solution mechanism and ion-exchange process occurred in zeolitic and non-zeolitic zones. Further, the hydrochemical parameters are appraised by means of dominancy of ions, rock–water interactions, silicate weathering, chloro-alkaline indices, cation-exchange bivariate plots and the mechanism controlling groundwater chemistry. The results show that: 1) the purifying efficiency of zeolites for total ionic strength is observed as 63.85 and 68.58% during pre- and post-monsoons, respectively, 2) the significant reduction (36.51%) in total hardness attributed to the positive trend of chloro-alkaline indices depicting the ion-exchange phenomenon between Na⁺ and K⁺ (alkalies) and Ca²⁺ and Mg²⁺ (alkali-earth) elements in the zeolitic zone, 3) Gibbs plot shows the rock–water interaction as the predominant mechanism controlling groundwater chemistry in the zeolitic zone, and 4) the groundwater quality parameters from zeolitic zone are found within the permissible limit of WHO drinking water standards.  相似文献   

Investigation of fluoride contamination and its mobility in groundwater of Simlapal block of Bankura district,West Bengal,India     

Sandip Mondal  Subodh Kumar 《Environmental Earth Sciences》2017,76(22):778

The occurrence of dental/skeletal fluorosis among the people in the study area provided the motivation to assess the distribution, severity and impact of fluoride contamination in groundwater of Bankura district at Simlapal block, West Bengal, India. To meet the desired objective, groundwater samples were collected from different locations of Laxmisagar, Machatora and Kusumkanali regions of Simlapal block at different depths of tube wells in both pre- and post-monsoon seasons. Geochemical results reveal that the groundwaters are mostly moderate- to hard-water type. Of total groundwater samples, 37% are situated mainly in relatively higher elevated region containing fluoride above 1.5 mg/L, indicating that host aquifers are severely affected by fluoride contamination. Machatora region is highly affected by fluoride contamination with maximum elevated concentration of 12.2 mg/L. Several symptoms of fluorosis among the different age-groups of people in Laxmisagar and Machatora areas are indicating consumption of fluoridated water for prolonged period. The groundwater samples were mainly Na–Ca–HCO₃ type and rock dominance indicating the dissolution of minerals taking place. Ion exchange between OH^? ion and F^? ion present in fluoride-bearing mineral is the most dominant mechanism of fluoride leaching. High concentration of Na⁺ and HCO₃ ^? increases the alkalinity of the water, providing a favorable condition for fluoride to leach into groundwater from its host rocks and minerals.  相似文献   

Identification of water-bearing fractures in hard rock terrain by electrical conductivity logs, India     

V. K. Saxena  N. C. Mondal  V. S. Singh  Dewashish Kumar 《Environmental Geology》2005,48(8):1084-1095

For the delineation of water-bearing fractures in hard rock areas, a new hydro-chemical technique has been developed which is based on electrical conductivity (EC) logs. The EC logs were carried out in experimental shallow bore wells (≈50 m) in three different parts of India. A sharp variation in EC was observed near water-bearing fractures in hard rock areas. To access applications of this technique, different locations in India were selected and experimental bore wells (≈50 m) were drilled. These were:

(1)	Maheswaram (30 km South of Hyderabad): nine shallow bore wells in a watershed of 60 km2 in granitic aquifers,
(2)	Wailpally (60 km East of Hyderabad): four shallow bore wells in a watershed of 50 km2 in granitic terrain.
(3)	Sadras (60 km SSW of Chennai): four shallow bore wells in a watershed 12 km2 in a charnokite aquifers.

Observations on EC logs were made at short intervals of 1.0 m from the water table (narrow spacing wherever required) until reaching the bottom of the wells. EC showed remarkable changes in value, which was attributed to the presence of water-bearing fractures in the hard rock areas. The results of this study are in good agreement with geophysical and geological findings. In addition to identifying the water-bearing fractures, the EC logs also provide various other hydrological and hydrochemical information, i.e., water table, total depth of the bore well, total dissolved solids (TDS), behavior of water–rock interaction, water quality, information about the chemistry of aquifers, etc.  相似文献   

A Study Of Global Monopole In Einstein–Cartan Theory     

F.?RahamanEmail author  R.?Mondal 《Astrophysics and Space Science》2005,299(2):167-174

The gravitational field of a global monopole in the context of Einstein–Cartan theory is investigated. A comparison is made with the corresponding results predicted by general relativity. PACS Nos: 98.80cq; 04.20 jb; 04.50  相似文献