Research Center Imarat

Hyderabad, India

Research Center Imarat

Hyderabad, India
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Jahagirdar D.R.,Research Center Imarat | Rao K.S.,Research Center Imarat
Asia-Pacific Microwave Conference Proceedings, APMC | Year: 2017

In this paper, a novel design for wideband high gain Right Hand Circular Polarized (RHCP) 2×4 array antenna at L-Band is presented for data link application. The proposed antenna used for long range highly maneuvering vehicles like missiles which needs high gain and RHCP to provide sufficient link margins. Orthogonal feeding is used for first patch and second patch is electromagnetically coupled to enhance impedance bandwidth. Sequential rotation technique is implemented to improve the Axial Ratio (AR) bandwidth. The antenna is simulated using commercially available software (CST microwave studio). The realized antenna reported 20.2% VSWR bandwidth, 14.64% AR bandwidth. The obtained gain is more than 14.5dBi, El & Az beamwidth of 44° and 20° over frequency band respectively. © 2016 IEEE.


Chatterjee S.,Research Center Imarat
AIP Conference Proceedings | Year: 2010

The Solid State Devices (SSD) which are increasingly being adopted in today's data storage Systems, have higher capacity and performance but lower reliability, which leads to more frequent rebuilds and to a higher risk. Although SSD is very energy efficient compared to Hard Disk Drives but Bit Error Rate (BER) of an SSD require expensive erase operations between successive writes. Parity based RAID (for Example RAID4,5,6)provides data integrity using parity information and supports losing of any one (RAID4, 5)or two drives(RAID6), but the parity blocks are updated more often than the data blocks due to random access pattern so SSD devices holding more parity receive more writes and consequently age faster. To address this problem, in this paper we propose a Model based System of hybrid disk array architecture in which we plan to use RAID 4(Stripping with Parity) technique and SSD drives as Data drives while any fastest Hard disk drives of same capacity can be used as dedicated parity drives. By this proposed architecture we can open the door to using commodity SSD's past their erasure limit and it can also reduce the need for expensive hardware Error Correction Code (ECC) in the devices. © 2010 American Institute of Physics.


Karunanidhi S.,Research Center Imarat | Singaperumal M.,Indian Institute of Technology Madras
Sensors and Actuators, A: Physical | Year: 2010

Flapper-nozzle type Electro Hydraulic Servo Valve (EHSV) operated by conventional torque motor actuators has been used in wide range of industrial applications. As their bandwidths are limited, they are not suitable for high-speed applications. The work presented in this paper deals with the mechatronic approach for the design of a magnetostrictive actuator with flexure amplifier and a magnetically biased magnetostrictive actuator for application in high frequency flapper-nozzle servo valve. A magnetostrictive actuator has been designed, built and integrated into an existing flapper-nozzle servo valve by replacing the torque motor. Incorporating the dynamics of the magnetostrictive actuator, the dynamics of the valve was simulated. Necessary parameters for the actuator have been arrived by finite element model. No load flow characteristics are analyzed and compared with experimental values. Step response has been compared with conventional valve. The results show that the valve has satisfactory static and dynamic characteristics for applications in high-speed actuation systems. © 2009 Elsevier B.V. All rights reserved.


Rayudu K.V.B.V.,Research Center Imarat
2015 International Conference on VLSI Systems, Architecture, Technology and Applications, VLSI-SATA 2015 | Year: 2015

A test procedure for testing the functionality of Interface Device DD-00429 between Microprocessor and Arinc 429 Data Bus is presented in this paper. This paper includes the test procedure for performing the synchronous write and read operation in Intel mode of the interface device. The driving voltage of 0.0v to4.0v is applied to input pins and sensing voltage from the output pins between 1v to 3v. The test is carried out using S790 Test System, Test Jig (DUT Adaptor) and 96 pin euro connector interfacing with Generic fixture of S790. The test program has been developed using CATE environment which includes the board description, component description, fixture description, and test plan. All the parameters implemented successfully. © 2015 IEEE.


Das A.K.,International Institute of Information Technology, Hyderabad | Sharma P.,International Institute of Information Technology, Hyderabad | Chatterjee S.,Research Center Imarat | Sing J.K.,Jadavpur University
Journal of Network and Computer Applications | Year: 2012

Most queries in wireless sensor network (WSN) applications are issued at the point of the base station or gateway node of the network. However, for critical applications of WSNs there is a great need to access the real-time data inside the WSN from the nodes, because the real-time data may no longer be accessed through the base station only. So, the real-time data can be given access directly to the external users (parties) those who are authorized to access data as and when they demand. The user authentication plays a vital role for this purpose. In this paper, we propose a new password-based user authentication scheme in hierarchical wireless sensor networks. Our proposed scheme achieves better security and efficiency as compared to those for other existing password-based approaches. In addition, our scheme has merit to change dynamically the users password locally without the help of the base station or gateway node. Furthermore, our scheme supports dynamic nodes addition after the initial deployment of nodes in the existing sensor network. © 2012 Elsevier Ltd.


Jahagirdar D.R.,Research Center Imarat
IEEE National Radar Conference - Proceedings | Year: 2012

A miniature DDS-based FMCW radar has been realized with dynamic range as high as 80 dB. A FMCW radar has many application as on-board sensor. The FMCW radar is a precision range measuring instrument. Hence it can be used for a variety of applications in aircrafts, helicopters and missiles. This paper describes in brief the design of one unique system which has been designed to operate in various modes. The difference come only at software level and setting of different thresholds for different applications. The major design difference here is the use of DDS to directly generate FMCW waveform and up-convert it to RF. It has many advantages over conventional FMCW signal generation. A linear FMCW system has been designed around this concept which resulted in sensitivity as good as -122 dBm and a high degree of slope linearity and repeatable in multiple units. A variety of antennas designed for different roles have made the system adaptable to various platform. The paper also shows results obtained and a critical comments on performance of total system and subsystems. © 2012 IEEE.


Karunanidhi S.,Research Center Imarat | Singaperumal M.,Indian Institute of Technology Madras
Proceedings of the Institution of Mechanical Engineers. Part I: Journal of Systems and Control Engineering | Year: 2010

A conventional two-stage servo valve basically consists of an electrically operated torque motor as the first stage and spool valve as the second stage. Owing to the limitation in the band width, servo valves are not suitable for high-frequency applications. The work presented in this paper deals with the methodology of the mechatronics approach for the design of a piezoelectric actuator with a mechanical amplifier and its integration into a servo valve. The analysis and simulation of a multilayer piezoelectric actuator (MLA) a with mechanical amplifier for high-frequency application has been done using icon-based bond graph technique and finite element coupled field analysis for the commercially available piezoelectric actuator. The designed piezoelectric actuator was integrated into an existing flapper-nozzle servo valve by replacing the first stage. The dynamics of the valve integrated into a piezoelectric actuator has been simulated. The required simulation parameters for the actuator have been derived from a finite element model. An experimental set-up has been designed and the integrated testing of the servo valve with piezoelectric actuator has been carried out to determine the no-load flow gain of the valve. Also the time response has been measured for a conventional servo valve and servo valve with piezoelectric actuator. The designed valve with a piezoelectric actuator has satisfactory static and dynamic characteristics for high-speed applications. © Authors 2010.


Chatterjee S.,Research Center Imarat | Das A.K.,International Institute of Information Technology, Hyderabad | Sing J.K.,Jadavpur University
Ad-Hoc and Sensor Wireless Networks | Year: 2014

Recently, Huang proposed a new access control scheme based on elliptic curve cryptosystem which prevents malicious nodes from joining the sensor network. This scheme uses the expiration time of nodes so that the nodes can only authenticate with its neighbor nodes within that time. In this paper, we first show that though this scheme is efficient, but it has a fatal weakness such as it is vulnerable to an active attack known as man-in-the-middle attack. In order to remedy that weakness we propose a more efficient and secure access control scheme as compared with Huang's scheme. Further, our scheme is significantly better in terms of performance and security compared with other related access control schemes. In fact, our scheme requires significantly less communication costs as compared to other related schemes. Moreover, we simulate our scheme for formal security analysis using the AVISPA (Automated Validation of Internet Security Protocols and Applications) tool and show that our scheme is secure. © 2014 Old City Publishing, Inc.


Das A.K.,International Institute of Information Technology, Hyderabad | Chatterjee S.,Research Center Imarat | Sing J.K.,Jadavpur University
International Journal of Foundations of Computer Science | Year: 2013

In a wireless sensor network, we often require the deployment of new nodes to extend the lifetime of the network because some sensor nodes may be lost due to power exhaustion problem or they may be also malicious nodes. In order to protect malicious nodes from joining the sensor network, access control mechanism becomes a major challenging problem in the design of sensor network protocols. Existing access control protocols designed for wireless sensor networks require either high communication overheads or they are not scalable due to involvement of the base station during authentication and key establishment processes. In this paper, we propose a new access control scheme for large-scale distributed wireless sensor networks, which not only identifies the identity of each node but it has also ability to differentiate between old nodes and new nodes. The proposed scheme does not require involvement of the base station during authentication and key establishment processes, and it can be easily implemented as a dynamic access control protocol. In addition, our scheme significantly reduces communication costs in order to authenticate neighbor nodes among each other and establish symmetric keys between neighbor nodes as compared with existing approaches. Further, our scheme is secure against different attacks and unconditionally secure against node capture attacks. The simulation results of our scheme using the AVISPA (Automated Validation of Internet Security Protocols and Applications) tool ensure that our scheme is safe. © 2013 World Scientific Publishing Company.


Raju K.,Osmania University | Balaji C.G.,Research Center Imarat | Venugopal Reddy P.,Osmania University
Journal of Magnetism and Magnetic Materials | Year: 2014

To investigate the influence of aluminum and manganese doping on structural, electrical, magnetic and microwave behavior of nickel ferrites, the samples were prepared by citrate sol-gel method. Samples were characterized by X-ray diffractometer using Rietveld refinement technique and are found to have cubic structure with space group Fd3̄m. A systematic investigation of magnetization, permeability, permittivity and microwave properties such as isolation, insertion loss and return loss was undertaken at Ku band (12-18 GHz) frequencies. A qualitative explanation for the various observed phenomena was given. © 2013 Elsevier B.V.

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