International Institute of Information Technology, Hyderabad

www.iiit.ac.in
Hyderabad, India

The International Institute of Information Technology, Hyderabad is an autonomous university in Hyderabad, Telangana, India. It was established in 1997, and is one of the top Computer Science institutes in the country. It emphasizes research from the undergraduate level. It has been a consistent performer from India in ACM International Collegiate Programming Contest and finished at #18 in 2012. Raj Reddy, the only Indian to win the Turing Award, is chairman of the board of governors.The institute runs Computer Science courses and research projects and is focused on research. It gives the students interaction with industry, preparation in entrepreneurship and personality development courses. IIIT Hyderabad is the mentor institute to Indian Institute of Information Technology, Sri City Wikipedia.


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Das A.K.,International Institute of Information Technology, Hyderabad | Bruhadeshwar B.,International Institute of Information Technology, Hyderabad
Journal of Medical Systems | Year: 2013

Recently Lee and Liu proposed an efficient password based authentication and key agreement scheme using smart card for the telecare medicine information system [J. Med. Syst. (2013) 37:9933]. In this paper, we show that though their scheme is efficient, their scheme still has two security weaknesses such as (1) it has design flaws in authentication phase and (2) it has design flaws in password change phase. In order to withstand these flaws found in Lee-Liu's scheme, we propose an improvement of their scheme. Our improved scheme keeps also the original merits of Lee-Liu's scheme. We show that our scheme is efficient as compared to Lee-Liu's scheme. Further, through the security analysis, we show that our scheme is secure against possible known attacks. In addition, we simulate our scheme for the formal security verification using the widely-accepted AVISPA (Automated Validation of Internet Security Protocols and Applications) tool to show that our scheme is secure against passive and active attacks. © Springer Science+Business Media New York 2013.


Sau T.K.,International Institute of Information Technology, Hyderabad | Rogach A.L.,City University of Hong Kong
Advanced Materials | Year: 2010

Metal nanoparticles have been the subject of widespread research over the past two decades. In recent years, noble metals have been the focus of numerous studies involving synthesis, characterization, and applications. Synthesis of an impressive range of noble metal nanoparticles with varied morphologies has been reported. Researchers have made a great progress in learning how to engineer materials on a nanometer length scale that has led to the understanding of the fundamental size- and shape-dependent properties of matter and to devising of new applications. In this article, we review the recent progress in the colloid-chemical synthesis of nonspherical nanoparticles of a few important noble metals {mainly Ag, Au, Pd, and Pt), highlighting the factors that influence the particle morphology and discussing the mechanisms behind the nonspherical shape evolution. The article attempts to present a thorough discussion of the basic principles as well as state-of-the-art morphology control in noble metal nanoparticles. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA.


Das A.K.,International Institute of Information Technology, Hyderabad
IET Information Security | Year: 2011

The author first reviews the recently proposed Li-Hwang's biometric-based remote user authentication scheme using smart cards; then shows that the Li-Hwang's scheme has some design flaws in their scheme. In order to withstand those flaws in their scheme, an improvement of their scheme is further proposed. The author also shows that the improved scheme provides strong authentication with the use of verifying biometric, password as well as random nonces generated by the user and the server as compared to that for the Li-Hwang's scheme and other related schemes. © 2011 The Institution of Engineering and Technology.


Priyakumar U.D.,International Institute of Information Technology, Hyderabad
Journal of Biomolecular Structure and Dynamics | Year: 2012

The role of salt bridges in chromatin protein Sso7d, from S. solfataricus has previously been shown to be crucial for its unusual high thermal stability. Experimental studies have shown that single site mutation of Sso7d (F31A) leads to a substantial decrease in the thermal stability of this protein due to distortion of the hydrophobic core. In the present study, we have performed a total of 0.2 μs long molecular dynamics (MD) simulations on F31A at room temperature, and at 360 K, close to the melting temperature of the wild type (WT) protein to investigate the role of hydrophobic core on protein stability. Sso7d-WT was shown to be stable at both 300 and 360 K; however, F31A undergoes denaturation at 360 K, consistent with experimental results. The structural and energetic properties obtained using the analysis of MD trajectories indicate that the single mutation results in high flexibility of the protein, and loosening of intramolecular interactions. Correlation between the dynamics of the salt bridges with the structural transitions and the unfolding pathway indicate the importance of both salt bridges and hydrophobic in effecting thermal stability of proteins in general. ©Adenine Press (2012).


Das A.K.,International Institute of Information Technology, Hyderabad
International Journal of Network Security | Year: 2012

In this paper, we propose a novel identity-based random key pre-distribution scheme called the identity based key pre-distribution using a pseudo random function (IBPRF), which has better trade-off between communication overhead, network connectivity and resilience against node capture compared to the other existing key pre-distribution schemes. IBPRF always guarantees that no matter how many sensor nodes are captured, the secret communication between non-compromised sensor nodes are still secure. We then propose an improved version of our scheme in a large-scale hierarchical wireless sensor network. This improved approach has better trade off among network connectivity, security, communication, computational and storage overheads, and scalability than the existing random key pre-distribution schemes. The strength of the proposed IBPRF scheme and its improved approach is establishing pairwise secret keys between neighboring nodes with scantling communication and computational overheads. The improved IBPRF approach further supports a large-scale sensor network for the network connectivity. Through the analysis we show that the improved IBPRF scheme provides better security and lower overheads than other existing schemes.


Dhananjaya N.,International Institute of Information Technology, Hyderabad
The Journal of the Acoustical Society of America | Year: 2012

In this paper, the acoustic-phonetic characteristics of steady apical trills--trill sounds produced by the periodic vibration of the apex of the tongue--are studied. Signal processing methods, namely, zero-frequency filtering and zero-time liftering of speech signals, are used to analyze the excitation source and the resonance characteristics of the vocal tract system, respectively. Although it is natural to expect the effect of trilling on the resonances of the vocal tract system, it is interesting to note that trilling influences the glottal source of excitation as well. The excitation characteristics derived using zero-frequency filtering of speech signals are glottal epochs, strength of impulses at the glottal epochs, and instantaneous fundamental frequency of the glottal vibration. Analysis based on zero-time liftering of speech signals is used to study the dynamic resonance characteristics of vocal tract system during the production of trill sounds. Qualitative analysis of trill sounds in different vowel contexts, and the acoustic cues that may help spotting trills in continuous speech are discussed.


Das A.K.,International Institute of Information Technology, Hyderabad
Journal of Medical Systems | Year: 2015

Recent advanced technology enables the telecare medicine information system (TMIS) for the patients to gain the health monitoring facility at home and also to access medical services over the Internet of mobile networks. Several remote user authentication schemes have been proposed in the literature for TMIS. However, most of them are either insecure against various known attacks or they are inefficient. Recently, Tan proposed an efficient user anonymity preserving three-factor authentication scheme for TMIS. In this paper, we show that though Tan’s scheme is efficient, it has several security drawbacks such as (1) it fails to provide proper authentication during the login phase, (2) it fails to provide correct updation of password and biometric of a user during the password and biometric update phase, and (3) it fails to protect against replay attack. In addition, Tan’s scheme lacks the formal security analysis and verification. Later, Arshad and Nikooghadam also pointed out some security flaws in Tan’s scheme and then presented an improvement on Tan’s s scheme. However, we show that Arshad and Nikooghadam’s scheme is still insecure against the privileged-insider attack through the stolen smart-card attack, and it also lacks the formal security analysis and verification. In order to withstand those security loopholes found in both Tan’s scheme, and Arshad and Nikooghadam’s scheme, we aim to propose an effective and more secure three-factor remote user authentication scheme for TMIS. Our scheme provides the user anonymity property. Through the rigorous informal and formal security analysis using random oracle models and the widely-accepted AVISPA (Automated Validation of Internet Security Protocols and Applications) tool, we show that our scheme is secure against various known attacks, including the replay and man-in-the-middle attacks. Furthermore, our scheme is also efficient as compared to other related schemes. © 2015, Springer Science+Business Media New York.


Das A.K.,International Institute of Information Technology, Hyderabad
Journal of Medical Systems | Year: 2015

An integrated EPR (Electronic Patient Record) information system of all the patients provides the medical institutions and the academia with most of the patients’ information in details for them to make corrective decisions and clinical decisions in order to maintain and analyze patients’ health. In such system, the illegal access must be restricted and the information from theft during transmission over the insecure Internet must be prevented. Lee et al. proposed an efficient password-based remote user authentication scheme using smart card for the integrated EPR information system. Their scheme is very efficient due to usage of one-way hash function and bitwise exclusive-or (XOR) operations. However, in this paper, we show that though their scheme is very efficient, their scheme has three security weaknesses such as (1) it has design flaws in password change phase, (2) it fails to protect privileged insider attack and (3) it lacks the formal security verification. We also find that another recently proposed Wen’s scheme has the same security drawbacks as in Lee at al.’s scheme. In order to remedy these security weaknesses found in Lee et al.’s scheme and Wen’s scheme, we propose a secure and efficient password-based remote user authentication scheme using smart cards for the integrated EPR information system. We show that our scheme is also efficient as compared to Lee et al.’s scheme and Wen’s scheme as our scheme only uses one-way hash function and bitwise exclusive-or (XOR) operations. Through the security analysis, we show that our scheme is secure against possible known attacks. Furthermore, we simulate our scheme for the formal security verification using the widely-accepted AVISPA (Automated Validation of Internet Security Protocols and Applications) tool and show that our scheme is secure against passive and active attacks. © 2015, Springer Science+Business Media New York.


Das A.K.,International Institute of Information Technology, Hyderabad
International Journal of Information Security | Year: 2012

Several symmetric-key distribution mechanisms are proposed in the literature, but most of them are not scalable or they are vulnerable to a small number of captured nodes. In this paper, we propose a new dynamic random key establishment mechanism in large-scale distributed sensor networks, which supports deployment of sensor nodes in multiple phases. In the existing random key distribution schemes, nodes do not refresh their own keys, and thus, the keys in their key rings remain static throughout the lifetime of the network. One good property of our dynamic key distribution scheme is that the already deployed nodes in a deployment phase refresh their own keys in key rings before another deployment phase occurs. The strength of the proposed scheme is that it provides high resilience against node capture as compared to that for the other existing random key distribution schemes. Through analysis and simulation results, we show that our scheme achieves better network performances as compared to those for the existing random key distribution schemes. Finally, we propose an extended version of our scheme for practical usefulness to support high network connectivity and resilience against node capture. © Springer-Verlag 2012.


Deepak K.S.,International Institute of Information Technology, Hyderabad | Sivaswamy J.,International Institute of Information Technology, Hyderabad
IEEE Transactions on Medical Imaging | Year: 2012

Diabetic macular edema (DME) is an advanced symptom of diabetic retinopathy and can lead to irreversible vision loss. In this paper, a two-stage methodology for the detection and classification of DME severity from color fundus images is proposed. DME detection is carried out via a supervised learning approach using the normal fundus images. A feature extraction technique is introduced to capture the global characteristics of the fundus images and discriminate the normal from DME images. Disease severity is assessed using a rotational asymmetry metric by examining the symmetry of macular region. The performance of the proposed methodology and features are evaluated against several publicly available datasets. The detection performance has a sensitivity of 100% with specificity between 74% and 90%. Cases needing immediate referral are detected with a sensitivity of 100% and specificity of 97%. The severity classification accuracy is 81% for the moderate case and 100% for severe cases. These results establish the effectiveness of the proposed solution. © 2011 IEEE.

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