Abstract

The process of scancorrelation is very useful in map building and localization in environments without any easily discernible landmarks. It involves estimating the relative transform between two given scans of data. This can be formulated as a posterior estimation problem over the transformation space. Since the posterior, the action model and the likelihood function are mostly nonlinear, a particle filter is used to estimate this posterior [1]. A GMM based correlation scheme has been used in [2] to drive the scan correlation process. In this paper, we propose a 3 step particle filtering approach that combines the simplicity and efficiency of the particle filter with the robustness of the GMM based correlation scheme. Experimental results are provided to verify the effectiveness of this approach.

Abstract

The Modular Legged robotic system [1] "Mod-Leg" presented here has been bio-inspired from a Snake's vertebrae and a caterpillar's legged structure. The system can be configured to a 4-legged robotic dog, a hexapod, a caterpillar and a Snake robot. This robot's novel design achieves compliance to the terrain using a combination of legs and electronically actuated universal spine. A unique simulator has been designed for this purpose. Some of the things we learned while developing this robotic system have been presented below.

Abstract

Capturing the shape and texture of large structures such as monuments and statues at very high resolution is extremely expensive, both in terms of time as well as storage space. In many cases the finer details are generated by surface properties of the material, and the appearance is statistically uniform. In this paper, we present an approach to add surface details to a coarse 3D model of an object based on two additional information: a set of images of the object and a high resolution model of the material that the object is made of. The material model that we employ is the Polynomial Texture Map (PTM), which captures the appearance of a surface under various illumination conditions. We use the observed images of the object as constraints to synthesize texture samples for each triangle of the object under any given illumination. The primary challenge is to synthesize a polynomial model of the texture, where the constraints arise in the image domain. We use the knowledge of object illumination to map the texture models into image space and compute the optimal patch. The texture transfer then happens as a complete 3D texturemodel. We also consider the problems of pose, scale, reflectance and smoothness of surface while carrying out the texture transfer. We synthesize the texture of an object at a per-triangle basis while carrying out operations such as normalization and blending to take care of discontinuities at the edges.

Abstract

We present a complete online handwritten character recognition system for Indian languages that handles the ambiguities in segmentation as well as recognition of the strokes. The recognition is based on a generative model of handwriting formation, coupled with a discriminative model for classification of strokes. Such an approach can seamlessly integrate language and script information in the generative model and deal with similar strokes using the discriminative stroke classification model. The recognition is performed in a purely bottomup fashion, starting with the strokes, and the ambiguities at each stage are preserved and transferred to the next stage for obtaining the most probable results at each stage. We also present the results of various preprocessing, feature selection and classification studies on a large data set collected from native language writers in two different Indian languages: Malayalam and Telugu. The system achieves a stroke level accuracy of 95.78% and 95.12% on Malayalam and Telugu data, respectively. The akshara level accuracy of the system is around 78% on a corpus of 60, 492 words from 367 writers.

Abstract

The use of camera as a biometric sensor is desirable due to its ubiquity and low cost, especially for mobile devices. Palmprint is an effective modality in such cases due to its discrimination power, ease of presentation and the scale and size of texture for capture by commodity cameras. However, the unconstrained nature of pose and lighting introduces several challenges in the recognition process. Even minor changes in pose of the palm can induce significant changes in the visibility of the lines. We turn this property to our advantage by capturing a short video, where the natural palm motion induces minor pose variations, providing additional texture information. We propose a method to register multiple frames of the video without requiring correspondence, while being efficient. Experimental results on a set of different 100 palms show that the use of multiple frames reduces the error rate from 12.75% to 4.7%. We also propose a method for detection of poor quality samples due to specularities and motion blur, which further reduces the EER to 1.8%.

Abstract

This paper introduces an efficient privacy-preserving protocol for distributed K-means clustering over an arbitrary partitioned data, shared among N parties. Clustering is one of the fundamental algorithms used in the field of data mining. Advances in data acquisition methodologies have resulted in collection and storage of vast quantities of user’s personal data. For mutual benefit, organizations tend to share their data for analytical purposes, thus raising privacy concerns for the users. Over the years, numerous attempts have been made to introduce privacy and security at the expense of massive additional communication costs. The approaches suggested in the literature make use of the cryptographic protocols such as Secure Multiparty Computation (SMC) and/or homomorphic encryption schemes like Paillier’s encryption. Methods using such schemes have proven communication overheads. And in practice are found to be slower by a factor of more than 106. In light of the practical limitations posed by privacy using the traditional approaches, we explore a paradigm shift to side-step the expensive protocols of SMC. In this work, we use the paradigm of secret sharing, which allows the data to be divided into multiple shares and processed separately at different servers. Using the paradigm of secret sharing, allows us to design a provably-secure, cloud computing based solution which has negligible communication overhead compared to SMC and is hence over a million times faster than similar SMC based protocols

Abstract

Concerns on widespread use of biometric authentication systems are primarily centered around template security, revocability, and privacy. The use of cryptographic primitives to bolster the authentication process can alleviate some of these concerns as shown by biometric cryptosystems. In this paper, we propose a provably secure and blind biometric authentication protocol, which addresses the concerns of user’s privacy, template protection, and trust issues. The protocol is blind in the sense that it reveals only the identity, and no additional information about the user or the biometric to the authenticating server or vice-versa. As the protocol is based on asymmetric encryption of the biometric data, it captures the advantages of biometric authentication as well as the security of public key cryptography. The authentication protocol can run over public networks and provide nonrepudiable identity verification. The encryption also provides template protection, the ability to revoke enrolled templates, and alleviates the concerns on privacy in widespread use of biometrics. The proposed approach makes no restrictive assumptions on the biometric data and is hence applicable to multiple biometrics. Such a protocol has significant advantages over existing biometric cryptosystems, which use a biometric to secure a secret key, which in turn is used for authentication. We analyze the security of the protocol under various attack scenarios. Experimental results on four biometric datasets (face, iris, hand geometry, and fingerprint) show that carrying out the authentication in the encrypted domain does not affect the accuracy, while the encryption key acts as an additional layer of security.

Abstract

Heritage could be something which is acquired from one’s ancestors. It could be natural heritage, cultural heritage, food heritage, built monumental heritage; or it could be the virtue of vernacular architectural & construction techniques which people from many different communities have secured from their ancestors through generations. But, with the advent of modernism, vernacular architecture, construction techniques and skills are fast disappearing as there is simply no demand for them anymore. Similar to the case with many of our traditional crafts, we are facing the risk of extinction of skills for buildings. As more and more constructions in villages are turning towards cement and steel, the traditional and sophisticated art of construction will fade away sooner rather than later. The preservation of such skills and, in fact their propagation must be an important priority for stakeholders and policy makers. This paper not only the presents the risks of extinction which these heritage construction techniques & skills are facing from modern mind-set, but it also presents some of the vernacular building typologies in seismic zones IV & V showing, their uniqueness in intertwining the culture and resistance to natural forces of the region.

Abstract

This paper presents the preliminary seismic hazard assessment of the peninsular India (lat. 10-26N and long. 68-90E) which is considered to be seismically most stable land masses of the Indian plate. Past major seismic events in this region (Koyna, 10 Dec 1967; Bhadrachalam, 13 Apr 1969; Hyderabad, 30 Jun 1983; Latur, 30 Sep 1993; Jabalpur, 22 May 1997; Bhuj, 26 Jan 2001) clearly shows that the seismicity of the area is highly varying. There were five damaging earthquakes with magnitudes Mw 6.0 occurred in this region, stressing the importance of detailed seismic hazard assessment for this region. For India, Bhatia published a probabilistic seismic hazard map based on several well identified and prominent source zones in the country. An attempt has been made in this paper to study the present seismic status of this region incorporating the detailed seismicity, tectonic and geologic characteristics. Around 110 major faults are considered in this present research study for estimating the peak ground acceleration at the bedrock level using the attenuation relationships developed by Atkinson and Boore. The considered area under peninsular region has been divided into grid pattern with 10x10 and around 280 site specific locations are considered for the detailed analysis. From this study, it is observed that 30% of PI is overestimated and 12% is underestimated when compared with PGA values for various regions provided in Indian seismic code IS: 1893-2002. The results show that there is a great need for carrying out the detailed microzonation of an area within the peninsular India.

Abstract

In the proximity of an active fault, spatial variation of peak ground motion is significantly affected by the faulting mechanism. It has been observed that near fault ground motions consists of different characteristics compared to the far fault ground motions. Near fault records, in the distance range of less than 100 m from the faults are not available except for few cases. Therefore numerical simulation of ground motions for such near-fault situations is necessary. In addition to the understanding of the phenomenon of near fault ground motion there is a need to enhance our understanding of the possible potential hazard that can be caused due to the future rupture activity by understanding the phenomenon of surface faulting. In this paper we propose numerical simulation based on discrete modeling to investigate the fault rupture propagation and its effect on the surface peak ground acceleration. In the present two dimensional study rupture propagation due to bedrock motion has been observed for different shear wave velocity. A model of size 1000 X 150 m is selected for this purpose. It has been observed that as the stiffness of the media is decreasing, the affected surface is decreasing and also width of the shear crack zone is decreasing. Secondly, we attempted to study the ground motion on the surface due to the bedrock motion in presence of boulders in the soil media. Surface faulting has been examined by keeping the boulder at different positions. We find that there is an increase in the shear zone as well as the PGA on the surface when the boulder is present on the foot wall and in the vicinity of the rupture zone. Finally, we performed the …