Anju Johnson

Dr. Anju Johnson

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Research Focus & Metrics

Academic Career Length

13Years (2014-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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10 May 2016 in IEEE Transactions on Circuits and Systems II: Express Briefs
Verified
Journal Article
Closed access
AJAnju Johnson
Anju Johnson
RCRajat Subhra Chakraborty
Rajat Subhra Chakraborty
DMDebdeep Mukhopadyay
Debdeep Mukhopadyay
True random number generators (TRNGs) play a very important role in modern cryptographic systems. Field-programmable gate arrays (FPGAs) form an ideal platform for hardware implementations of many of these security algorithms. In this brief, we present a highly efficient and tunable TRNG based on the principle of beat frequency detection, specifically for Xilinx-FPGA-based applications. The main advantages of the proposed TRNG are its on-the-fly tunability through dynamic partial reconfiguration to improve randomness qualities. We describe the mathematical model of the TRNG operations and experimental results for the circuit implemented on a Xilinx Virtex-V FPGA. The proposed TRNG has low hardware footprint and built-in bias elimination capabilities. The random bitstreams generated from it pass all tests in the NIST statistical testsuite.

26 October 2015 in IEEE Transactions on Multi-Scale Computing Systems
Verified
Journal Article
Closed access
AJAnju Johnson
Anju Johnson
RCRajat Subhra Chakraborty
Rajat Subhra Chakraborty
DMDebdeep Mukhopadhyay
Debdeep Mukhopadhyay
The Internet of Things (IoT) is a dynamic, ever-evolving “living” entity. Hence, modern Field Programmable Gate Array (FPGA) devices with Dynamic Partial Reconfiguration (DPR) capabilities, which allow in-field non-invasive modifications to the circuit implemented on the FPGA, are an ideal fit. Usually, the activation of DPR capabilities requires the procurement of additional licenses from the FPGA vendor. In this work, we describe how IoTs can take advantage of the DPR capabilities of FPGAs, using a modified DPR methodology that does not require any paid “add-on” utility, to implement a lightweight cryptographic security protocol. We analyze possible threats that can emanate from the availability of DPR at IoT nodes, and propose possible solution techniques based on Physically Unclonable Function (PUF) circuits to prevent such threats.

31 July 2018 in IEEE Transactions on Neural Networks and Learning Systems
Verified
Journal Article
Closed access
JLJunxiu Liu
Junxiu Liu
LDLiam Mc Daid
Liam Mc Daid
Jim HarkinJim Harkin
Jim Harkin
SKShvan Karim
Shvan Karim
AJAnju Johnson
Anju Johnson
JTJonathan Timmis
Jonathan Timmis
It is now known that astrocytes modulate the activity at the tripartite synapses where indirect signaling via the retrograde messengers, endocannabinoids, leads to a localized self-repairing capability. In this paper, a self-repairing spiking astrocyte neural network (SANN) is proposed to demonstrate a distributed self-repairing capability at the network level. The SANN uses a novel learning rule that combines the spike-timing-dependent plasticity (STDP) and Bienenstock, Cooper, and Munro (BCM) learning rules (hereafter referred to as the BSTDP rule). In this learning rule, the synaptic weight potentiation is not only driven by the temporal difference between the presynaptic and postsynaptic neuron firing times but also by the postsynaptic neuron activity. We will show in this paper that the BSTDP modulates the height of the plasticity window to establish an input-output mapping (in the learning phase) and also maintains this mapping (via self-repair) if synaptic pathways become dysfunctional. It is the functional dependence of postsynaptic neuron firing activity on the height of the plasticity window that underpins how the proposed SANN self-repairs on the fly. The SANN also uses the coupling between the tripartite synapses and ɣ-GABAergic interneurons. This interaction gives rise to a presynaptic neuron frequency filtering capability that serves to route information, represented as spike trains, to different neurons in the subsequent layers of the SANN. The proposed SANN follows a feedforward architecture with multiple interneuron pathways and astrocytes modulate synaptic activity at the hidden and output neuronal layers. The self-repairing capability will be demonstrated in a robotic obstacle avoidance application, and the simulation results will show that the SANN can maintain learned maneuvers at synaptic fault densities of up to 80% regardless of the fault locations.

1 July 2017 in Microprocessors and Microsystems
Verified
Journal Article
Open access
AJAnju Johnson
Anju Johnson
SPSikhar Patranabis
Sikhar Patranabis
RCRajat Subhra Chakraborty
Rajat Subhra Chakraborty
DMDebdeep Mukhopadhyay
Debdeep Mukhopadhyay

31 March 2020 in Sensors
Verified
Journal Article
Open access
PDF file
Hussain Al-AqrabiHussain Al-Aqrabi
Hussain Al-Aqrabi
AJAnju Johnson
Anju Johnson
Richard HillRichard Hill
Richard Hill
PLPhil Lane
Phil Lane
TATariq Alsboui
Tariq Alsboui
The introduction of 5G communication capabilities presents additional challenges for the development of products and services that can fully exploit the opportunities offered by high bandwidth, low latency networking. This is particularly relevant to an emerging interest in the Industrial Internet of Things (IIoT), which is a foundation stone of recent technological revolutions such as Digital Manufacturing. A crucial aspect of this is to securely authenticate complex transactions between IIoT devices, whilst marshalling adversarial requests for system authorisation, without the need for a centralised authentication mechanism which cannot scale to the size needed. In this article we combine Physically Unclonable Function (PUF) hardware (using Field Programmable Gate Arrays—FPGAs), together with a multi-layer approach to cloud computing from the National Institute of Standards and Technology (NIST). Through this, we demonstrate an approach to facilitate the development of improved multi-layer authentication mechanisms. We extend prior work to utilise hardware security primitives for adversarial trojan detection, which is inspired by a biological approach to parameter analysis. This approach is an effective demonstration of attack prevention, both from internal and external adversaries. The security is further hardened through observation of the device parameters of connected IIoT equipment. We demonstrate that the proposed architecture can service a significantly high load of device authentication requests using a multi-layer architecture in an arbitrarily acceptable time of less than 1 second.

13 February 2017
Verified
Conference Paper
Closed access
AJAnju Johnson
Anju Johnson
DHDavid M. Halliday
David M. Halliday
AMAlan G. Millard
Alan G. Millard
ATAndy M. Tyrrell
Andy M. Tyrrell
JTJonathan Timmis
Jonathan Timmis
SKShvan Karim
Shvan Karim
The human brain is structured with the capacity to repair itself. This plasticity of the brain has motivated researchers to develop systems which have similar capabilities of fault tolerance and self-repair. Recent research findings have proven that interactions between astrocytes and neurons can actuate brain-like self-repair in a bidirectionally coupled astrocyte-neuron system. This paper presents a hardware realization of the bio-inspired self-repair architecture on an FPGA. We also introduce a reduced architecture for an FPGA-based hardware-efficient fault-tolerant system. This is based on the principle of retrograde signaling in an astrocyte-neuron network by simplifying the calcium dynamics within the astrocyte. The hardware optimized implementation shows more than a 90% decrease in hardware utilization and proves an efficient implementation for a large-scale astrocyte-neuron network. An Average spike rate of 0:027 spikes per clock cycle were observed for both the proposed models of astrocytes in the case of 100% partial fault.