Sensor Verification for Cyber-Physical Models of Power Systems

This project explores the ways that data from sensors in power systems can be authenticated by enhancing the security of power systems from a cyber-physical point of view. This is a continuation of the work for the NSF project “CPS: Synergy: Collaborative Research: Distributed Just-Ahead-Of-Time Verification of Cyber-Physical Critical Infrastructure.” Adversaries who gain access to a cyber-physical system can cause significant physical damage and financial loss by injecting false data into a sensor node. Identifying adversarial action in a system can mitigate unsafe actions made based off of bad data. The technique presented in this work combines topology analysis with real-time probing to create a measure of trustworthiness of sensors in a system. A previously developed tool called Cyber Physical Security Assessment (CyPSA) gives each node a topology vulnerability score based on the cyber accessibility and potential physical impact should it be compromised. We develop a real-time vulnerability score by simulating attack and non-attack scenarios with PowerWorld. The data from these simulations is processed in MATLAB. Results show improved attack detection over current methods. The measure of trustworthiness developed will improve attack detection in power systems, and it may be used to help prevent a system from entering an unstable state

Sensor Verification for Cyber-Physical Models of Power Systems

This project explores the ways that data from sensors in power systems can be authenticated by enhancing the security of power systems from a cyber-physical point of view. This is a continuation of the work for the NSF project “CPS: Synergy: Collaborative Research: Distributed Just-Ahead-Of-Time Verification of Cyber-Physical Critical Infrastructure.” Adversaries who gain access to a cyber-physical system can cause significant physical damage and financial loss by injecting false data into a sensor node. Identifying adversarial action in a system can mitigate unsafe actions made based off of bad data. The technique presented in this work combines topology analysis with real-time probing to create a measure of trustworthiness of sensors in a system. A previously developed tool called Cyber Physical Security Assessment (CyPSA) gives each node a topology vulnerability score based on the cyber accessibility and potential physical impact should it be compromised. We develop a real-time vulnerability score by simulating attack and non-attack scenarios with PowerWorld. The data from these simulations is processed in MATLAB. Results show improved attack detection over current methods. The measure of trustworthiness developed will improve attack detection in power systems, and it may be used to help prevent a system from entering an unstable state

Development and application of synchronized wide-area power grid measurement

Phasor measurement units (PMUs) provide an innovative technology for real-time monitoring of the operational state of entire power systems and significantly improve power grid dynamic observability. This dissertation focuses on development and application of synchronized power grid measurements. The contributions of this dissertation are as followed:First, a novel method for successive approximation register analog to digital converter control in PMUs is developed to compensate for the sampling time error caused by the division remainder between the desirable sampling rate and the oscillator frequency. A variable sampling interval control method is presented by interlacing two integers under a proposed criterion. The frequency of the onboard oscillator is monitored in using the PPS from GPS.Second, the prevalence of GPS signal loss (GSL) on PMUs is first investigated using real PMU data. The correlation between GSL and time, spatial location, solar activity are explored via comprehensive statistical analysis. Furthermore, the impact of GSL on phasor measurement accuracy has been studied via experiments. Several potential solutions to mitigate the impact of GSL on PMUs are discussed and compared.Third, PMU integrated the novel sensors are presented. First, two innovative designs for non-contact PMUs presented. Compared with conventional synchrophasors, non-contact PMUs are more flexible and have lower costs. Moreover, to address nonlinear issues in conventional CT and PT, an optical sensor is used for signal acquisition in PMU. This is the first time the utilization of an optical sensor in PMUs has ever been reported.Fourth, the development of power grid phasor measurement function on an Android based mobile device is developed. The proposed device has the advantages of flexibility, easy installation, lower cost, data visualization and built-in communication channels, compared with conventional PMUs.Fifth, an identification method combining a wavelet-based signature extraction and artificial neural network based machine learning, is presented to identify the location of unsourced measurements. Experiments at multiple geographic scales are performed to validate the effectiveness of the proposed method using ambient frequency measurements. Identification accuracy is presented and the factors that affect identification performance are discussed

Geo-location estimation from Electrical Network Frequency signals

Electric Network Frequency (ENF) fluctuations based forensic anal-ysis is an emerging way for such multimedia authentication tasks as time-of-recording estimation, timestamp verification, and clip in-sertion/deletion forgery detection. ENF fluctuates due to dynamic changes in load demand and power supply, and these fluctuations travel over the power lines with a finite speed. In this paper, experi-ments are conducted on ENF data collected across different locations in the eastern grid of the United States to understand the relation-ship between the signals recorded at the same time at these locations. Based on these experiments, a signal processing mechanism is devel-oped to demonstrate that ENF fluctuations across different locations exhibit a measure of similarity with each other, which is proportional to the distance between the locations. Such observations motivated a location estimation protocol based on the similarity of ENF sig-nals with respect to anchor nodes. Under certain conditions, the pro-posed protocol is shown to provide an estimation accuracy of 90%. Challenges in the application of ENF signal analysis for location of recording estimation of multimedia signal are also discussed. 1

Image and Video Forensics

Nowadays, images and videos have become the main modalities of information being exchanged in everyday life, and their pervasiveness has led the image forensics community to question their reliability, integrity, confidentiality, and security. Multimedia contents are generated in many different ways through the use of consumer electronics and high-quality digital imaging devices, such as smartphones, digital cameras, tablets, and wearable and IoT devices. The ever-increasing convenience of image acquisition has facilitated instant distribution and sharing of digital images on digital social platforms, determining a great amount of exchange data. Moreover, the pervasiveness of powerful image editing tools has allowed the manipulation of digital images for malicious or criminal ends, up to the creation of synthesized images and videos with the use of deep learning techniques. In response to these threats, the multimedia forensics community has produced major research efforts regarding the identification of the source and the detection of manipulation. In all cases (e.g., forensic investigations, fake news debunking, information warfare, and cyberattacks) where images and videos serve as critical evidence, forensic technologies that help to determine the origin, authenticity, and integrity of multimedia content can become essential tools. This book aims to collect a diverse and complementary set of articles that demonstrate new developments and applications in image and video forensics to tackle new and serious challenges to ensure media authenticity