A Comparative Investigation of Image Fusion in the Context of Classification

Image fusion assists in visual interpretation, mapping, change detection and many other applications. Multispectral and Panchromatic images are fused to produce images having enhanced spatial and spectral properties. These properties are generally distorted from original images. The aim of this paper is to identify the effectiveness of the several fusion techniques based on the distortions and applications. This paper employs seven image fusion techniques namely, Brovey transform, intensity hue saturation, high pass filter, principle component analysis, UNB Pansharpening, wavelet transform and multiplicative, available in various commercial image processing software. The data for this study are panchromatic image of Cartosat-1 and multispectral image of IRS - P6 LISS 4 sensor of study area, Bhopal Municipal Corporation area, M.P. State, India. The effectiveness of image fusion techniques is determined by quantitative and qualitative assessments. Quantitative assessment is divided into two parts: 1) assessment of fusion techniques by statistical parameters and 2) accuracy assessment of land use maps generated from the fused images. For part 1, three parameters namely, mean bias, correlation coefficient and Q4 quality index, have been used. Based on the results of part 1, UNB Pansharpening and wavelet transform are the best among seven fusion techniques. For part 2, Gaussian and Artificial Neural Network classifiers have been used to generate land cover maps. However, the accuracy results are inconclusive to identify a single best method. Nevertheless, image fusion by wavelet transform has provided best results in both the sector. Hence, wavelet transform is concluded as the best among selected fusion techniques.     

Simultaneous optimization of the performance of flotation circuits and their simplification using the jumping gene adaptations of genetic algorithm-II: More complex problems

The binary-coded elitist non-dominated sorting genetic algorithm with the modified jumping gene operator (NSGA-II-mJG) is used to obtain global optimal solutions of flotation circuits. Several single-objective and multi-objective optimization problems are solved using the interconnecting cell linkage parameters (fraction flow rates) and the mean cell residence times as the decision variables. In the single-objective problem, the overall recovery of the concentrate stream is maximized for a desired grade of the concentrate. Two two-objective optimization problems are then solved. In one, the number of non-linking streams and the overall recovery of the concentrate are maximized simultaneously. This gives several simple circuits in a systematic manner with only marginally lower recoveries. In the other two-objective optimization problem, the overall recovery of the concentrate is maximized while the total cell volume is minimized. A three-objective problem (maximization of the overall recovery of the concentrate, maximization of the number of non-linking streams and minimization of the total cell volume) is then solved. All the problems constrain the grade of the product to lie at a fixed value. Finally, a complex and computationally intensive four-objective optimization problem is solved. The solution of several practical optimization problems in this study helps develop useful insights into the optimal solutions.     

Impact of Climate Change on Indian Agriculture: A Review

During the recent decade, with the growing recognition of the possibility of climate change and clear evidence of observed changes in climate during 20^th century, an increasing emphasis on food security and its regional impacts has come to forefront of the scientific community. In recent times, the crop simulation models have been used extensively to study the impact of climate change on agricultural production and food security. The output provided by the simulation models can be used to make appropriate crop management decisions and to provide farmers and others with alternative options for their farming system. It is expected that in the coming decades with the increased use of computers, the use of simulation models by farmers and professionals as well as policy and decision makers will increase. In India, substantial work has been done in last decade aimed at understanding the nature and magnitude of change in yield of different crops due to projected climate change. This paper presents an overview of the state of the knowledge of possible effect of the climate variability and change on food grain production in India. An erratum to this article can be found at     

Observations of trace gases and aerosols over the Indian Ocean during the monsoon transition period

Characteristics of trace gases (O₃, CO, CO₂, CH₄ and N₂O) and aerosols (particle size of 2.5 micron) were studied over the Arabian Sea, equatorial Indian Ocean and southwest part of the Bay of Bengal during the monsoon transition period (October–November, 2004). Flow of pollutants is expected from south and southeast Asia during the monsoonal transition period due to the patterns of wind flow which are different from the monsoon period. This is the first detailed report on aerosols and trace gases during the sampled period as the earlier Bay of Bengal Experiment (BOBMEX), Arabian Sea Monsoon Experiment (ARMEX) and Indian Ocean Experiments (INDOEX) were during monsoon seasons. The significant observations during the transition period include: (i) low ozone concentration of the order of 5 ppbv around the equator, (ii) high concentrations of CO₂, CH₄ and N₂O and (iii) variations in PM2.5 of 5–20μg/m³.     

Extraction of Coal Under a Surface Water Body – a Strata Control Investigation

Summary. The extraction of coal seams under built-up structures and especially under water bodies has been a challenge to the miners due to the potential risk of disturbance to the surface. A number of safety and ground control problems are associated with the mining operations under water bodies. These can be dealt with through proper planning for the optimization of coal recovery and systematic strata control investigations. At Godavari khani (GDK) no. 3 incline of the Singareni Collieries Company Limited (SCCL), two panels namely SS-10/1A and SS-10/1B in no. 1 seam, were identified for extraction under the surface water body called Janagaon tank. A feasibility study was carried out by the authors for working these panels, and hydraulic sand stowing method was recommended. Further, strata behaviour monitoring was carried out using remote type geotechnical instruments during the extraction of pillars in one of the panels. The extraction of the pillars in the experimental panel progressed smoothly without any strata control problems. The mine management could extract coal reserves in the panel with more than 60% recovery, which were otherwise unworkable. This paper presents the feasibility of extraction of pillars under the Janagaon tank, and strata behaviour observations made during the actual extraction.     

Normalized impedance function and the straightforward inversion scheme for magnetotelluric data

This paper investigates the performance of normalized response function obtained by normalizing the Cagniard impedance function by a suitable factor and then rotating the phase by 45‡ to make it purely real for homogeneous half-space and equal to the square root of the half-space resistivity. Two apparent resistivity functions based on respectively the real and imaginary parts of this response function are proposed. The apparent resistivity function using the real part contains almost the same information as that yielded by the Cagniard expression while the one using the imaginary part qualitatively works as an indicator of the number of interfaces in the earth model. The linear straightforward inversion scheme (SIS), developed by the authors employing the concept of equal penetration layers, has been used to validate the proposed apparent resistivity functions. For this purpose, several synthetic and field models have been examined. Five synthetic models are studied to establish the veracity of the new functions and two well-studied published field data sets are inverted through SIS for comparison. We noticed that the new function and SIS compliment each other and lead to better understanding of the data information and model resolution.     

Alkaline Magmatism Versus Collision Tectonics in the Eastern Ghats Belt, India: Constraints from Structural Studies in the Koraput Complex

Linear domains of deformed alkaline rocks and carbonatites have recently been identified as representing sites of ancient suture zones. In peninsular India, the western margin of the Proterozoic Eastern Ghats Belt (EGB) is characterized by a series of alkaline plutons that are aligned close to the contact with the Archaean Craton. Most of the complexes were deformed and metamorphosed during a subsequent orogenic event. Unlike other plutons in the belt, the alkaline complex at Koraput reportedly escaped deformation and granulite facies metamorphism forming an anomalous entity within the zone. Multiply-deformed country rocks hosting this complex underwent syn-D_1CR granulite facies metamorphism followed by D_2CR thrusting, with pervasive shearing along a NE-SW trending foliation. A second granulite facies event followed localized D_3CR shearing. Within the Koraput Complex, strain partitioning was responsible for preserving igneous textures in the gabbroic core, but aligned magmatic amphibole needles and plagioclase laths occasionally define a S_1AC fabric. Along the margins, S_1AC is rotated parallel to a NE-trending, east-dipping S_2AC fabric in the gabbro, fringing syenodiorite and nepheline syenite bands. Locally, D_3AC shearing follows D_2AC deformation; S_2AC and S_3AC parallel S_2CR and S_3CR in the country rocks. High-grade metamorphism represented by recrystallization of amphibole and plagioclase, and breakdown of amphibole and biotite to garnet, pyroxene and K-feldspar in the complex follows D_3AC. Unlike earlier reports, therefore, the Koraput body is also deformed and metamorphosed. The aligned alkaline complexes in the EGB probably represent deformed alkaline rocks and carbonatites formed by rifting related to an earlier episode of continental break-up that were deformed during subsequent juxtaposition of the EGB with the Archaean Craton. This supports the contention that the western margin of the EGB and its contact with the Archaean Craton is a suture zone related to the Indo-Antarctica collision event.     

Assimilation of Doppler weather radar observations in a mesoscale model for the prediction of rainfall associated with mesoscale convective systems

Obtaining an accurate initial state is recognized as one of the biggest challenges in accurate model prediction of convective events. This work is the first attempt in utilizing the India Meteorological Department (IMD) Doppler radar data in a numerical model for the prediction of mesoscale convective complexes around Chennai and Kolkata. Three strong convective events both over Chennai and Kolkata have been considered for the present study. The simulation experiments have been carried out using fifth-generation Pennsylvania State University-National Center for Atmospheric Research (PSU-NCAR) mesoscale model (MM5) version 3.5.6. The variational data assimilation approach is one of the most promising tools available for directly assimilating the mesoscale observations in order to improve the initial state. The horizontal wind derived from the DWR has been used alongwith other conventional and non-conventional data in the assimilation system. The preliminary results from the three dimensional variational (3DVAR) experiments are encouraging. The simulated rainfall has also been compared with that derived from the Tropical Rainfall Measuring Mission (TRMM) satellite. The encouraging result from this study can be the basis for further investigation of the direct assimilation of radar reflectivity data in 3DVAR system. The present study indicates that Doppler radar data assimilation improves the initial field and enhances the Quantitative Precipitation Forecasting (QPF) skill.     

The effect of pH of water and mineralogical properties on the slake durability (degradability) of different rocks from the Lesser Himalaya, India

Slake durability is an important geotechnical parameter and is a measure of degradability of rocks due to the process of mechanical and chemical breakdown. It is closely related to the mineralogical composition and the texture of the rocks. In this paper, mineralogical examination along with slake durability tests under variable pH conditions, both in acidic and alkaline environments, on the limestone, shale and siltsone were evaluated to understand the relationship between mineralogy and the degradability of rocks. The study revealed that rocks rich in calcium carbonate and or magnesium carbonate are adversely affected in the acidic environment, whereas, the rocks rich in quartz, feldspar and muscovite are independent of the pH of the slaking fluid, which in turn, is more influenced by the texture of the constituent minerals. It has also been observed that fine grained rocks are more susceptible to degrade in comparison to the coarse grained rocks.