Journal Articles
Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/19884
Browse
69 results
Search Results
Item Land cover change and its implication to hydrological regimes and soil erosion in Awash River basin, Ethiopia: a systematic review(Springer Science and Business Media Deutschland GmbH, 2021) Tola, S.Y.; Shetty, A.The Awash River basin is one of the most developed basins in Ethiopia, and its water resources are crucial to development. The collective impact of land cover (LC) changes has driven a difference in the hydrological components, substantially impacting the availability of water resources and demand. This review aimed (i) to examine the extent of change quantitatively and its effects; (ii) to analyze the relationship with a mean annual rainfall that would further reveal the causes and potential LC type response to hydrologic variables in the Awash River basin, Ethiopia. The results have revealed that urbanization and agricultural activities in the basin are the most trending types of LC, while the forest, shrubland, grassland, and pasture land have been decreasing significantly in the subbasins. As a result, the change in these subbasins has triggered hydrologic variations (runoff, groundwater flow, base flow, and evapotranspiration), and its impacts on downstream basins have mostly been flood and drought. In addition, farmland, urbanization, and shrubland trends showed a significant positive interaction, while forest and water bodies had a substantial and slight negative relation to mean annual rainfall, respectively. Vegetation, bareland, urbanization, and agriculture/farmland are directly responsible for the hydrologic variation. LC change significantly affected hydrologic regimes and the distribution of spatial rainfall is correlated significantly to LC change pattern. Besides, due to the lack of LC management practices, the impact continues to propagate. Hence, this review helps to portray the potential implications and extent of effects of changes in LC on the hydrological regimes. As a result, the implementation of sound water management strategies and practices in response to changing environments to resurrect water scarcity and mitigate flood and sediment are needed straightaway. © 2021, The Author(s), under exclusive licence to Springer Nature Switzerland AG.Item Performance evaluation of dimensionality reduction techniques on hyperspectral data for mineral exploration(Springer Science and Business Media Deutschland GmbH, 2023) C, D.; Shetty, A.; Narasimhadhan, A.V.With recent advances in hardware and wide range of applications, hyperspectral remote sensing proves to be a promising technology for analysing terrain. However, the sheer volume of bands, strong inter band correlation and redundant information makes interpretation of hyperspectral data a tedious task. Aforementioned issues can be addressed to a considerable extent by reducing the dimensionality of hyperspectral data. Though plethora of algorithms exist to downsize hyperspectral data, quality assessment of these techniques remains unanswered. Since Dimensionality Reduction (DR) is a special case of unsupervised learning, classification accuracy cannot be directly used to compare the performance of different dimensionality reduction techniques. As a consequence, a different type of goodness measure is essential which is expected to be easily interpretable, robust against outliers and applicable to most algorithms and datasets. In this paper, fifteen popular dimensionality reduction algorithms are reviewed, evaluated and compared on hyperspectral dataset for mineral exploration. The performance of various DR algorithms is tested on hyperspectral mineral data since the extensive study of DR for mineral mapping is scarce compared to land cover mapping. Also, DR techniques are evaluated based on coranking criteria which is independent of label information. This facilitates to demonstrate the robust technique for mineral mapping and also provides meaningful insight into topology preservation. These techniques play a vital role in mineral exploration since in field observation is expensive, time consuming and requires more man power. From experimental results it is evident that, deep autoencoders provide better embedding with a quality index value of 0.9938, when K = 120 compared to other existing nonlinear techniques. The conclusions presented are unique since previous studies have not evaluated the results qualitatively and comparison between conventional machine learning and deep learning algorithms is limited. © 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.Item Mineral classification on Martian surface using CRISM hyperspectral data: a survey(SPIE, 2023) Kumari, P.; Soor, S.; Shetty, A.; Koolagudi, S.G.The compact Reconnaissance Imaging Spectrometer for Mars (CRISM) has significantly advanced our understanding of the mineralogy of Mars. With its enhanced spectral and spatial resolution, CRISM has enabled the identification and characterization of various minerals on the Martian surface, providing valuable insights into Mars’ past climate and geologic history, as well as the evolution of the planet’s atmosphere and climate. We present a comprehensive review of mineral identification on Mars using CRISM data. We discuss the data description, pre-processing techniques, different spectrum libraries, geological characteristics used for mineral identification, challenges, and methodologies used for mineral classification, such as learning models, probabilistic methods, and neural networks. We highlight major findings of minerals on the Martian surface and discuss validation techniques. We conclude with a discussion of further research to address the existing gaps and challenges in this field. Overall, we provide a general understanding of mineral classification using CRISM data and could serve as a helpful resource for researchers and scientists interested in planetary remote sensing and mineral identification on the Martian surface. © 2023 Society of Photo-Optical Instrumentation Engineers (SPIE)Item [No abstract available](Land use - land cover mapping using satellite data for a forested watershed, Udupi district, Karnataka State, India) Shetty, A.; Nandagiri, L.; Thokchom, S.; Rajesh, M.V.S.2005Item Study on the strength parameters of high volume fly ash concrete and geopolymer concrete(2011) Shetty, A.; Anand, V.R.; Hegde, P.Concrete has been the most preferred construction material. It is being increasingly used day by day all over the world due to its versatility, mould ability and high compressive strength. But the large-scale production of cement is causing environmental problems on one hand and the unrestricted depletion of natural resources on the other. So the issue of sustainable development in concrete construction is addressed in this paper through development of concrete mixes by replacing certain percentage of cement with fly ash. Trials on concrete mixes with replacement of 40%, 50%, 60% and 70% of cement with fly ash are carried out and the results depict that at the replacement level of 40% cement by fly ash, the required strength is achieved. It is also observed that the rate of early strength gain is retarded as the percentage replacement of cement increases. But in case of Geopolymer concrete (100% replacement of cement by fly ash) under a curing temperature around 600C and above, the strength gain rate is very high in initial stages. It is observed that design strength is achieved within 28 hours of oven curing. © 2011 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.Item Spatial variation in drainage characteristics and geomorphic instantaneous unit hydrograph (GIUH); implications for watershed management-A case study of the Varada River basin, Northern Karnataka(2011) Bhagwat, T.N.; Shetty, A.; Hegde, V.S.Geomorphological characteristics can be treated as signatures of hydrological responses. Geomorphologic instantaneous unit hydrograph (GIUH) is of utmost use in planning watershed management programs on a broad scale in absence of hydrologic data. Fifth order basins from different agroclimatic zones in the Varada River basin were selected to understand the spatial variation in drainage characteristics. These sub-basins show significant differences in their morphometric properties such as basin area, drainage density, bifurcation ratio, circularity ratio, constant of channel maintenance etc. These differences reflect variation in the hydrological process and geomorphologic instantaneous unit hydrograph (GIUH) of different sub-basins and can be used to understand watershed management aspects. Fifth order sub-basin in the Southern Transition agroclimatic zone is potential for artificial recharge programs. Sub-basins in the Hilly non-forest zone on the north are ideal for surface water storage like tank development program while Forested Hilly zone on the north are environmentally sensitive and prone to erosion. © 2011 Elsevier B.V.Item Land use scenario analysis and prediction of runoff using SCS-CN method: A case study from the Gudgudi tank, Haveri district, Karnataka, India(2011) Bhagwat, N.B.; Shetty, A.; Hegde, V.S.Runoff from the Gudgudi tank catchment (209 ha) near Hangal in the Northern Karnataka is estimated employing Soil Conservation Services(SCS) model based on the hydrological data and land use/ land cover data. Rainfall measured for 2006 using a tipping bucket indicated annual rainfall of 887.7mm in the tank catchment. Textural characteristics of the soil indicate sandy-clayey type which corresponds to hydrological soil group "C and D". Average Soil infiltration rate of 0.18 cm/hour for the forest-land and 0.21 cm/hour for agriculture land has been observed. Weighted curve number is arrived based on the antecedent moisture conditions, and runoff is estimated for the existing land-use. Areastorage curve is constructed using the tank bed contours. Considering the hypothetical changes in the agriculture and forest area coverage, optimum conditions for maximizing the runoff and storage in the tank is arrived. The analysis suggests land use pattern of 15% of forest cover and 85% of agriculture land coverage in this region provide maximum runoff and storage in the tank for sustainable development. © 2011 CAFET-INNOVA TECHNICAL SOCIETY.Item Performance evaluation of rebar in accelerated corrosion by gravimetric loss method(2012) Shetty, A.; Venkataramana, K.; Gogoi, I.Corrosion of concrete occurs due to chloride ingress into concrete and is a major cause of steel corrosion. Rebar corrosion in concrete is one of the major problems in the durability criteria. This paper explains, experimental investigations carried out on smaller specimens for evaluating the performance of two types of cement with three types of rebar by gravimetric method. From the results of gravimetric loss obtained by different types of steel with different types of concrete, it is concluded that blended cement, i.e. PPC performs better compared to OPC against accelerated rebar corrosion in concrete. Amongst steel types, CTD steel resulted in higher gravimetric loss compared to MS followed by TMT steel. © 2012 Cafet-Innova Technical Society. All rights reserved.Item A study on corrosion behavior of electrodeposited Zn-rutile TiO2 composite coatings(2012) Kumar, M.K.P.; Venkatesha, T.V.; Pavithra, M.K.; Shetty, A.The Zn and Zn-TiO2 composite coatings were fabricated by electrolyzing respective plating solutions of Zn and Zn-TiO2. The rutile TiO2 nanoparticles (size ?100nm) were used for the preparation of composite coatings. The corrosion behavior of the deposits was examined by electrochemical methods. The anticorrosive property of coatings was supported by measuring their corrosion potential, polarization resistance, charge transfer characteristic peak and break frequency. The surface morphology of deposits was studied by scanning electron microscopy, energydispersive X-ray diffraction spectroscopy, and X-ray diffraction techniques. The change in morphology of Zn-TiO2 composite with respect to Zn is correlated with their corrosion behavior. Copyright © Taylor & Francis Group, LLC.