Nellore, India
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Bhaskar A.,NBKRIST | Babu U.R.,NBKRIST
2016 IEEE Annual India Conference, INDICON 2016 | Year: 2016

Diode based bridge rectifiers (AC to DC power converters) are the widely used power supplies. The major drawbacks of the conventional diode bridge rectifiers and thyristor-based rectifiers (nonlinear loads) are low power factor and high current harmonics in AC supply. This paper presents the design of a digital controller for continuous conduction mode boost converter with power factor correction on Xilinx FPGA. It is designed to minimize or reduce input current harmonic distortion by reducing the total harmonic distortion (THD) and improving the power factor of power supplies. The pre-calculated duty cycle control is implemented in FPGA for power factor correction in order to avoid the costly and complex process of current measurement. To obtain stable output voltages even in the presence of uncertainties (load variations) and disturbances (input voltage variations) a voltage loop with a fuzzy logic controller is included. © 2016 IEEE.


Bala Anki Reddy P.,Vellore Institute of Technology | Bhaskar Reddy N.,N.B.K.R.I.S.T | Suneetha S.,Rashtreeya Vidyalaya College of Engineering
Journal of Applied Fluid Mechanics | Year: 2012

The radiation effects on unsteady flow of a viscous incompressible fluid past an exponentially accelerated infinite isothermal vertical plate with uniform mass diffusion is considered in the presence of magnetic field and heat source. The governing partial differential equations are converted into a non-dimensional form and solved numerically by applying a Crank-Nicholson type of implicit finite difference method with a tri-diagonal matrix manipulation and an iterative procedure. The profiles of unsteady velocity, temperature and concentration are shown graphically for different values of thermo physical parameters. Also, the simulated values of the skin-friction coefficient, Nusselt number and Sherwood number are presented. This model finds applications in solar energy collection systems, geophysics and astrophysics, aero space and also in the design of high temperature chemical process systems.


Sarvabhatla M.,NBKRIST | Vorugunti C.S.,Dhirubhai Ambani Institute of ICT
2015 7th International Conference on Communication Systems and Networks, COMSNETS 2015 - Proceedings | Year: 2015

The advancement of semiconductor and ubiquitous technology resulted in a smart sensor networking system, which is an application of wireless sensor networks to health care applications (WMSN). Wireless Medical Sensor Network (WMSN) is a real-time continuous patient monitoring system, which provides a cost-optimal wireless sensor networking platform to track patient's physiological data through the sensors attached to patient body. Limited computational power, storage, communication and energy capacity of WMSN demands for energy efficient, light weight and high security mutual authentication schemes which provides unbreakable connectivity for end to end secure data delivery. In 2014, He et al. proposed an authentication scheme for WMSN and claimed that their scheme is light weight and resists all major cryptographic attacks. However, in this paper we will show that He et al scheme is vulnerable to offline password guessing attack and other major ones. As a part of our contribution, we will propose an energy efficient, light weight and highly secure authentication scheme for WMSN which 56%more energy efficient compared to He et al scheme and 20.18%compared to Kumar et al scheme. © 2015 IEEE.


Sarvabhatla M.,NBKRIST | Vorugunti C.S.,Dhirubhai Ambani Institute of ICT
2015 7th International Conference on Communication Systems and Networks, COMSNETS 2015 - Proceedings | Year: 2015

Emerging markets looks cloud computing as a facilitator to lower their investments related to ICT. Unlimited throughput, on demand and elastic nature of cloud attracted the medium and large scale organizations to adopt it and move their critical data, software resources to cloud. Outsourcing of critical data to third party results in lots of security issues like user authentication, integrity of data etc. and need to be addressed very effectively. In 2011, Hao et al of SUNY, have proposed a time-bound ticket-based mutual authentication scheme and claimed that their scheme is secure. In 2013, Jaidhar et al claimed that Hao et al scheme is vulnerable to DoS attack and proposed an improved scheme. In this paper, we will show that Jaidhar et al scheme is still vulnerable to all major cryptographic attacks like offline password guessing attack, user impersonation attack, server masquerade attack etc. As a part of our contribution, we propose an improved mutual authentication scheme, which is secure and resistant to all major cryptographic attacks. © 2015 IEEE.


Sarvabhatla M.,NBKRIST | Vorugunti C.S.,Dhirubhai Ambani Institute of ICT
Proceedings - 4th International Conference on Emerging Applications of Information Technology, EAIT 2014 | Year: 2014

The advancement of research on the Internet of Things (IoT) results in WSN to become an integral part of it, which results in, the users can access the sensor data from an insecure public communication channel. Remote user authentication and mutual authentication among the communicating entities are the critical requirements in WSN. Lots of researchers have proposed 2-factor and 3-factor authentication protocols to authenticate the user trying to access the sensor data. Recently A.K Das et al., proposed a biometric-based remote user authentication scheme using smart card, and claimed that their protocol achieves mutual authentication and resists all major cryptographic attacks. In this paper we will show that their scheme requires high computation cost for resource constrained sensor nodes and has several vulnerabilities, which includes failure to resist replay attack, user impersonation attack, failure to achieve mutual authentication and failure to provide data privacy. As a part of our contribution, we propose an improved authentication scheme which resists all major cryptographic attacks, with less computation cost compared to A.K Das et al., and other similar schemes. © 2014 IEEE.


Sarvabhatla M.,NBKRIST | Vorugunti C.S.,Dhirubhai Ambani Institute of ICT
7th International Workshop on Signal Design and Its Applications in Communications, IWSDA 2015 | Year: 2015

As networking and wireless communication technologies advance more rapidly, it give rise to a quick change in the m-commerce land scape. The insecure public internet as an access medium resulted in lots of cryptographic attacks on wireless transactions. Due to this, there is an extreme demand for light weight and secure authentication protocols. In this context, few researchers have proposed E.C.C based authentication schemes to validate the legitimacy of the user connecting to remote server. Recently Islam et al has proposed a dynamic ID based authentication scheme using E.C.C and claimed that their scheme is secure and flexible. In this manuscript, we will illustrate that their scheme is susceptible to offline password guessing attack and user impersonation attack. We then communicate a secure and robust authentication scheme, which is resistant to all cryptographic attacks and light weight. We have analyzed security strengths of our scheme formally using random oracle model and game theory. © 2015 IEEE.


Sarvabhatla M.,NBKRIST | Reddy M.C.M.,VelTech University | Vorugunti C.S.,Dhirubhai Ambani Institute of ICT
ACM International Conference Proceeding Series | Year: 2015

The advancement of web and mobile technologies results in the rapid augmentation of traditional enterprise data, IoT generated data, social media data which outcomes in peta bytes and exa bytes of structured and un structured data across clusters of servers per day. The storage, processing, analyzing and securing these big data is becoming a serious concern to large and medium enterprises. Hadoop or HDFS is a distributed file system based on cloud for storage and processing of large voluminous amounts of data across clusters of servers. Along with huge potential for dynamism for processing and scalability, HDFS also brought inherent security drawbacks like lack of authentication and authorization of remote user connecting to cluster, missing of encryption of sensitive data at communication, storage and processing levels. These existing drawbacks demands for a robust, light weight security framework for HDFS. In this context, we propose a secure and light weight remote user authentication framework for HDFS, which guarantees all the critical security requirements of a distributed file system. © 2015 ACM.


Sarvabhatla M.,NBKRIST | Reddy M.C.M.,VelTech University | Vorugunti C.S.,Dhirubhai Ambani Institute of ICT
ACM International Conference Proceeding Series | Year: 2015

The advancements in networking technology resulted in emergence of Wireless Mesh Networks (WMNs) on top of IEEE 802.11 standard to provide flexible and adaptive network architecture to next-generation wireless networks. Research proved that IEEE 802.11 is vulnerable to DoS and Man in the Middle attacks. Hence, WMN is also vulnerable to similar attacks. In this context, recently Somanath et al has provided an authentication framework for WMN and claimed that their framework is attack resistant. In this manuscript, after thorough evaluation of somanath et al authentication scheme, we have originated few inconsistencies and we will demonstrate that their scheme is vulnerable to replay and user impersonation attacks etc. As part of our contribution, we have developed a light weight authentication framework for WMN which is robust and attack resistant by preserving the merits of somanath et al framework. © 2015 ACM.


Sarvabhatla M.,NBKRIST | Reddy M.C.M.,VelTech University | Vorugunti C.S.,Dhirubhai Ambani Institute of ICT
ACM International Conference Proceeding Series | Year: 2015

The advancements in mobile and semiconductor technology resulted in a new area of internet based patient monitoring system called Wireless Medical Sensor Network (WMSN).The transferring of patient sensitive data, aggregated through patient body sensors, over insecure internet, demands for patient identity preserving and data privacy. In this context, many researchers have provided authentication schemes based on various factors. Due to the inherent advantage of light key weight and computation cost, ECC based authentication systems got great demand. Recently Lu et al had provided an authentication and key agreement protocol between WMSN server and user based on ECC. However, in this manuscript, we will demonstrate that Lu et al scheme fails to achieve fundamental requirements of WMSN i.e. preserving user anonymity and resisting impersonation attacks. Further, we propose our robust authentication scheme and we demonstrate the security strengths of our scheme both formally using BAN logic and informally. The formal security analysis confirms that our proposed scheme resists all relevant security attacks. © 2015 ACM.


Sarvabhatla M.,NBKRIST | Reddy M.C.,VelTech University | Vorugunti C.S.,DhirubhaiAmbani Institute of ICT
ACM International Conference Proceeding Series | Year: 2015

Cloud computing is a virtualization of computing resources which facilitates the outsourcing of computing, storage and networking resources elastic to geographically segregated users. Due to hosting of sensitive organizational data in the far off third party server and accessing those resources through insecure Internet, results in stringent requirements for data integrity and user authenticity. In this context, recently Mishra et al has proposed an identity based authentication scheme in cloud context and supported that their scheme is faultless. In this manuscript, we analyze the security aspects of Mishra et al scheme and demonstrate that their scheme is susceptible to user impersonation attack, replay attack etc. As a part of our contribution, we proposed a robust identity based authentication scheme and validate both formally and informally that our scheme is attack resistant. © 2015 ACM.

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