Correntropy: Answer to non-Gaussian noise in modern SLAM applications?

The problem of non-Gaussian noise/outliers has been intrinsic in modern Simultaneous Localization and Mapping (SLAM) applications. Despite numerous algorithms in SLAM, it has become crucial to address this problem in the realm of modern robotics applications. This work focuses on addressing the above-mentioned problem by incorporating the usage of correntropy in SLAM. Before correntropy, multiple attempts of dealing with non-Gaussian noise have been proposed with significant progress over time but the underlying assumption of Gaussianity might not be enough in real-life applications in robotics.Most of the modern SLAM algorithms propose the `best' estimates given a set of sensor measurements. Apart from addressing the non-Gaussian problems in a SLAM system, our work attempts to address the more complex part concerning SLAM: (a) If one of the sensors gives faulty measurements over time (`Faulty' measurements can be non-Gaussian in nature), how should a SLAM framework adapt to such scenarios? (b) In situations where there is a manual intervention or a 3rd party attacker tries to change the measurements and affect the overall estimate of the SLAM system, how can a SLAM system handle such situations?(addressing the Self Security aspect of SLAM). Given these serious situations how should a modern SLAM system handle the issue of the previously mentioned problems in (a) and (b)? We explore the idea of correntropy in addressing the above-mentioned problems in popular filtering-based approaches like Kalman Filters(KF) and Extended Kalman Filters(EKF), which highlights the `Localization' part in SLAM. Later on, we propose a framework of fusing the odometeries computed individually from a stereo sensor and Lidar sensor (Iterative Closest point Algorithm (ICP) based odometry). We describe the effectiveness of using correntropy in this framework, especially in situations where a 3rd party attacker attempts to corrupt the Lidar computed odometry. We extend the usage of correntropy in the `Mapping' part of the SLAM (Registration), which is the highlight of our work. Although registration is a well-established problem, earlier approaches to registration are very inefficient with large rotations and translation. In addition, when the 3D datasets used for alignment are corrupted with non-Gaussian noise (shot/impulse noise), prior state-of-the-art approaches fail. Our work has given birth to another variant of ICP, which we name as Correntropy Similarity Matrix ICP (CoSM-ICP), which is robust to large translation and rotations as well as to shot/impulse noise. We verify through results how well our variant of ICP outperforms the other variants under large rotations and translations as well as under large outliers/non-Gaussian noise. In addition, we deploy our CoSM algorithm in applications where we compute the extrinsic calibration of the Lidar-Stereo sensor as well as Lidar-Camera calibration using a planar checkerboard in a single frame. In general, through results, we verify how efficiently our approach of using correntropy can be used in tackling non-Gaussian noise/shot noise/impulse noise in robotics applications

Securing a UAV Using Features from an EEG Signal

This thesis focuses on an approach which entails the extraction of Beta component of the EEG (Electroencephalogram) signal of a user and uses his/her EEG beta data to generate a random AES (Advanced Encryption Standard) encryption key. This Key is used to encrypt the communication between the UAVs (Unmanned aerial vehicles) and the ground control station. UAVs have attracted both commercial and military organizations in recent years. The progress in this field has reached significant popularity, and the research has incorporated different areas from the scientific domain. UAV communication became a significant concern when an attack on a Predator UAV occurred in 2009, which allowed the hijackers to get the live video stream. Since a UAVs major function depend on its onboard auto pilot, it is important to harden the system against vulnerabilities. In this thesis, we propose a biometric system to encrypt the UAV communication by generating a key which is derived from Beta component of the EEG signal of a user. We have developed a safety mechanism that gets activated in case the communication of the UAV from the ground control station gets attacked. This system was validated on a commercial UAV under malicious attack conditions during which we implement a procedure where the UAV return safely to an initially deployed "home" position

Nitrogen Concentration Estimation in Tomato Leaves by VIS-NIR Non-Destructive Spectroscopy

Nitrogen concentration in plants is normally determined by expensive and time consuming chemical analyses. As an alternative, chlorophyll meter readings and N-NO3 concentration determination in petiole sap were proposed, but these assays are not always satisfactory. Spectral reflectance values of tomato leaves obtained by visible-near infrared spectrophotometry are reported to be a powerful tool for the diagnosis of plant nutritional status. The aim of the study was to evaluate the possibility and the accuracy of the estimation of tomato leaf nitrogen concentration performed through a rapid, portable and non-destructive system, in comparison with chemical standard analyses, chlorophyll meter readings and N-NO3 concentration in petiole sap. Mean reflectance leaf values were compared to each reference chemical value by partial least squares chemometric multivariate methods. The correlation between predicted values from spectral reflectance analysis and the observed chemical values showed in the independent test highly significant correlation coefficient (r = 0.94). The utilization of the proposed system, increasing efficiency, allows better knowledge of nutritional status of tomato plants, with more detailed and sharp information and on wider areas. More detailed information both in space and time is an essential tool to increase and stabilize crop quality levels and to optimize the nutrient use efficiency

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Not AvailableDaily crop ET of Triticum austivum L. and Cajanus cajan L. was monitored with gravimetric lysimeter during 1995-1997 at Rahuri, India (long. 780 18’ E and lat.190 45’ N) and was compared with various ETo models by statistical indicators like RMSE, MBE, t-statistic for adoption in semi-arid region of India. The crop evapotranspiration, on an average of three years was 1068.2 mm during crop growing season however, the reference evapotranspiation (ETo) in case of Hargreaves model was 1864.3 mm, the open pan 1636.6 mm, radiation balance 2335.0 mm, FAO56 Penman Monteith 1597.5 mm, Blaney Criddle 2021.5 mm and Modified Penman 2508.3 mm. The FAO56- PM model had lowest RMSE (2.89 mm day-1 ) and MBE (1.05 mm day-1 ) followed by Hargreaves (RMSE 3.28 mm day-1 ). The seasonal crop ET was 537.9 mm in red gram and 418.1 mm in wheat. The regression analysis between crop coefficient (Kc) and ETo models were agreeable in Hargreaves and Modified Penman model as evidenced by higher R2 values. Similarly regression analysis between crop coefficient and cumulative GDD had significant response with R2 of 0.57 to 0.83 in wheat and R2 0.31 to 0.59 in red gram. The regression analysis between SDD and crop coefficient had R2 0. 94 in red gram and 0.90 in wheatNot Availabl

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Not AvailableThe groundwater resources of Chhattisgarh are quite high but its exploitation is only 20.43%, which is very low as compared to other states of India. Within districts, spatial variation on ground water use is there and the coefficient of variation is as high as 106.2 %. In agriculture sector groundwater use is considerably low and needs adequate ground water structures for exploitation. In all districts, annual rainfall is very high but its distribution is erratic as 87-91% of annual rainfall is received during rainy season. The computed rainfall recharged study by various methods reveals that 14.35 to 23.4 % of annual rainfall is recharged and contributed to groundwater. This recharged rainwater of 3.69 million ha-m (computed based on geographical area of each district) can irrigate 2.26 million ha area considering annual ETo of 1.646 m. This state is cereal-dominated crops and consume maximum share of water with less water productivity. Hence pulses and oilseeds crops may be introduced on large scale. During kharif season total ETo demand of all crops was 2.078 million ha-m and during rabi/summer season 0.425 million ha-m. This demand has been estimated based on ET crops and area covered by each crop. So to harvest potential crop yield during both the season, recharged annual rainwater is not sufficient to cope up the demand of crops and hence abstraction of ground water through dug well, shallow tube well and deep tube well and in-situ rain water harvest technology is highly essential to improve crop yield economic return of the farmers.Not Availabl

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Not AvailableGroundwater being one of the most valuable resources of earth needs to be utilized properly for the healthy and economic growth of any region. The present study was carried out in Eastern part of India, where it is blessed with plenty of water resources but its utilization is very poor as compared to another part of India, which has been reflected through net cropped area, cropping intensity etc. Orissa, being one of the resource-rich States in India still struggles with low crop production and cropping intensity status. The groundwater development of the state is only 18.31 % out of total replenish able groundwater resources of 2100928 hectare meter (ha-m). Groundwater recharge being one of the most important components in the hydrologic cycle, it has to be estimated for any particular area before planning for any interventions. The natural groundwater recharge was only 22.31 % to 24.87% of the annual rainfall received in 30 districts of Orissa. The highest amount of recharge of 39.75cm was from Balasore and the lowest recharge of 26.47cm was in Rayagarh district of Orissa. However the estimation method was very crude as it is based on only rainfall of the particular area. More detail study on recharge aspects can be done under basin studies in the different region. Assessment of groundwater resources and planning for efficient use of groundwater in the agriculture sector has been planned based on crop water demand of each district of Orissa. The groundwater earmarked for irrigation is 1678038 ha-m. Considering crop water demand of 1030.5 mm (as per FAO 56 Penman-Monteith) during dry month period (November to May) the expected area to be irrigated is 1628372 ha. Since rice is dominated crop of this region even during rabi and summer season, another high-value cash crop through groundwater use is economically viable. For exploiting groundwater during rabi season, it is essential to know under-utilized and over utilized blocks of Orissa as the coefficient of variation was as high 133 % in Jagatsingpur district to as low as 1.43 % in Deogarh district. The groundwater development was a maximum of 77.61 % in Baliapal block in Balasore district. This block is dominated with summer paddy (January to April/May), which needs more frequent irrigation water for harvesting optimum yield.Not Availabl