Department of Civil Engineering

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Author: search.filters.author.Gupta, RajivEnd date: 2009

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Now showing 1 - 10 of 11
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    Feature preserving speckle filtering of the SAR images by wavelet transform
    (Springer, 2008-07-10) Gupta, Rajiv; Gupta, Karunesh K
    Synthetic Aperture Radar (SAR) images are corrupted by speckle noise due to random interference of electromagnetic waves. The speckle degrades the quality of the image and makes it difficult to interpret, analyse and classify. This paper proposes a method that reduces the speckle and preserves the features by using scale-space correlation between the scales. The results show that the proposed method is better than the widely used filters based on the spatial domain, such as Lee, Kuan, Frost, Ehfrost, Median, Gamma filters in terms of feature preservation. Moreover the proposed method achieves a wide range of balances between speckle reduction and feature preservation, and thus is applicable in different applications such as road detection, detection/ identification of bridge, and ribbon like structures. Furthermore, the proposed method does not require prior modeling of either the image or noise statistics. It uses the variance of the detail wavelets coefficients to estimate noise variance.
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    New Static Sunshade Design for Energy-Efficient Buildings
    (ASCE, 2006-04) Gupta, Rajiv
    Energy conservation inside the buildings is of utmost importance. To reduce the heating and cooling loads inside the energy-efficient buildings, solar entry regulation as per season can be attained with the use of specific sunshades. Although various static sunshades have been developed depending upon solar geometry, the efficiency with respect to control of solar entry inside the building is a major concern over the seasonal classification for a particular geographic location. The proposed work aims at the design development of a new static sunshade depending on solar angles, whose efficiency has been experimentally verified using a small-scale modeling technique. Three experimental models of insulating material were prepared with varying aspect ratio of windows and static sunshades. Sunlit area, which in turn controls the temperature inside the models, has been made the criteria for deciding the effectiveness of the proposed sunshade over existing horizontal sunshade. The proposed technique can be applied at any geographic location over the world for which sunshade can be designed as per the climatic requirements of the place
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    An Algorithm of Road Enhancement in SAR Images using Wavelet Transform
    (Springer, 2007) Gupta, Rajiv; Gupta, Karunesh K
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    Prediction of Concrete Strength Using Neural-Expert System
    (ASCE, 2006-06) Gupta, Rajiv; Kewalramani, Manish A.
    Over the years, many methods have been developed to predict the concrete strength. In recent years, artificial neural networks (ANNs) have been applied to many civil engineering problems with some degree of success. In the present paper, ANN is used as an attempt to obtain more accurate concrete strength prediction based on parameters like concrete mix design, size and shape of specimen, curing technique and period, environmental conditions, etc. A total of 864 concrete specimens were cast for compressive strength measurement and verification through the ANN model. The back propagation-learning algorithm is employed to train the network for extracting knowledge from training examples. The predicted strengths found by employing ANN are compared with the actual values. The results indicate that ANN is a useful technique for predicting the concrete strength. Further, an effort to build an expert system for the problem is described in this paper. To overcome the bottleneck of intricate knowledge acquisition, an expert system is used as a mechanism to transfer engineering experience into usable knowledge through rule-based knowledge representation techniques.
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    Concrete compressive strength prediction using ultrasonic pulse velocity through artificial neural networks
    (Elsiever, 2006-05) Gupta, Rajiv
    Numerous attempts to use ultrasonic pulse velocity (UPV) as a measure of compressive strength of concrete has been made due to obvious advantages of non-destructive testing methods. The present study is conducted for prediction of compressive strength of concrete based on weight and UPV for two different concrete mixtures (namely M20 and M30) involving specimens of two different sizes and shapes as a result of need for rapid test method for predicting long-term compressive strength of concrete. The prediction is done using multiple regression analysis and artificial neural networks. A comparison between two methods depicts that artificial neural networks can be used to predict the compressive strength of concrete effectively. The results are plotted as experimentally evaluated compressive strength versus predicted strength through both methods of analysis.
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    Design development of a static sunshade using small scale modeling technique
    (Elsiever, 2005-05) Gupta, Rajiv
    The rising global demand for energy has triggered emphasis on conservation of energy. Buildings are one of the important energy consuming sectors. Passive solar architecture encompasses a wide range of strategies and options resulting in energy efficient building design and increased occupant's comfort. Passive solar design, aiming at increasing direct solar gains during winter period and to avoid overheating during summer period should make use of specific shading devices over energy efficient window. The static sunshades are most effective for solar control inside the buildings.
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    Environmental Impact Analysis Using Fuzzy Relation for Landfill Siting
    (ASCE, 2003-09) Gupta, Rajiv
    Technological and industrial developmental project activities disturb the natural ecosystem and have multiple direct and indirect environmental consequences. The disposal of waste material, being a prominent activity that accompanies any industrial development, is a problem of ever-increasing concern. Therefore it is of immense importance to establish appropriate sites for waste disposal facilities such as landfills. To select an appropriate landfill site with minimal environmental damage, an environmental impact assessment (EIA) is necessary. Available methods to carry out an EIA are insufficient for cumulative assessment and inappropriate to make the final decision regarding the selection of a landfilling site, nor do they take uncertainty and future impacts into account. The present work implements fuzzy logic, which takes uncertainty into account in assessing the environmental impact of landfill siting and considers future impacts in terms of frequency of occurrence. A new approach that considers numeric values of the weights in terms of fuzzy membership is examined, the potential applicability of the method is tested, and results are compared with those of other common existing methods.
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    Extended Use of Linear Graph Theory for Analysis of Pipe Networks
    (ASCE, 2000-01) Gupta, Rajiv
    Linear graph theory used for pipe network analysis is to make the method systematic. A numerical method that uses linear graph theory is presented for the steady-state analysis of flow and pressure in a pipe network including its hydraulic components (pumps, valves, junctions, etc.). The proposed method differs from other linear graph methods in terms of the linear graph and the selection of its tree. The solution algorithm uses a function that depends on a power law to update the pipe flows in successive iterations. The exponents of this function are chosen to obtain a fast convergence rate even for large errors in the assumption of initial pipe flows. The convergence rate of the proposed method is validated using an error function and is compared to those of other methods. Some typical networks are analyzed to check the reliability of the proposed method. The results demonstrate the superior conditioning of the proposed method.
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