806 citations · 1.6k across the 33 of their papers we have counts for
36 papers
Assessing the Optimality of LinDist3Flow for Optimal Tap Selection of Step Voltage Regulators in Unbalanced Distribution Networks
Krishna Sandeep Ayyagari, Sherin Ann Abraham, Yiyun Yao +4
The adoption of distributed energy resources such as photovoltaics (PVs) has increased dramatically during the previous decade. The increased penetration of PVs into distribution n…
Observers for Differential Algebraic Equation Models of Power Networks: Jointly Estimating Dynamic and Algebraic States
Sebastian Nugroho, Ahmad Taha, Nikolaos Gatsis +1
Phasor measurement units ({PMUs}) have become instrumental in modern power systems for enabling real-time, wide-area monitoring and control. Accordingly, many studies have investig…
Rejection of Smooth GPS Time Synchronization Attacks via Sparse Techniques
Erick Schmidt, Junhwan Lee, Nikolaos Gatsis +1
This paper presents a novel time synchronization attack (TSA) model for the Global Positioning System (GPS) based on clock data behavior changes in a higher-order derivative domain…
Revisiting the Water Quality Sensor Placement Problem: Optimizing Network Observability and State Estimation Metrics
Ahmad F. Taha, Shen Wang, Yi Guo +4
Real-time water quality (WQ) sensors in water distribution networks (WDN) have the potential to enable network-wide observability of water quality indicators, contamination event d…
A GPS spoofing detection and classification correlator-based technique using the LASSO
Erick Schmidt, Nikolaos Gatsis, David Akopian
This work proposes a global navigation satellite system (GNSS) spoofing detection and classification technique for single antenna receivers. We formulate an optimization problem at…
Probabilistic State Estimation in Water Networks
Shen Wang, Ahmad F. Taha, Nikolaos Gatsis +2
State estimation in water distribution networks (WDN), the problem of estimating all unknown network heads and flows given select measurements, is challenging due to the nonconvexi…
A New Derivative-Free Linear Approximation for Solving the Network Water Flow Problem with Convergence Guarantees
Shen Wang, Ahmad F. Taha, Lina Sela +2
Addressing challenges in urban water infrastructure systems including aging infrastructure, supply uncertainty, extreme events, and security threats, depend highly on water distrib…
State Estimation in Water Distribution Networks through a New Successive Linear Approximation
Shen Wang, Ahmad F. Taha, Lina Sela +2
State estimation (SE) of water distribution networks (WDNs) is difficult to solve due to nonlinearity/nonconvexity of water flow models, uncertainties from parameters and demands,…
Receding Horizon Control for Drinking Water Networks: The Case for Geometric Programming
Shen Wang, Ahmad F. Taha, Nikolaos Gatsis +1
Optimal, network-driven control of Water Distribution Networks (WDN) is very difficult: valve and pump models form non-trivial, combinatorial logic; hydraulic models are nonconvex;…
Tuning-Free, Low Memory Robust Estimator to Mitigate GPS Spoofing Attacks
Junhwan Lee, Ahmad F. Taha, Nikolaos Gatsis +1
The operation of critical infrastructures such as the electrical power grid, cellphone towers, and financial institutions relies on precise timing provided by stationary GPS receiv…
Designing reactive power control rules for smart inverters using support vector machines
Mana Jalali, Vassilis Kekatos, Nikolaos Gatsis +1
Smart inverters have been advocated as a fast-responding mechanism for voltage regulation in distribution grids. Nevertheless, optimal inverter coordination can be computationally…
Geometric Programming-Based Control for Nonlinear, DAE-Constrained Water Distribution Networks
Shen Wang, Ahmad F. Taha, Nikolaos Gatsis +1
Control of water distribution networks (WDNs) can be represented by an optimization problem with hydraulic models describing the nonlinear relationship between head loss, water flo…
Optimal Power Flow with Step-Voltage Regulators in Multi-Phase Distribution Networks
Mohammadhafez Bazrafshan, Nikolaos Gatsis, Hao Zhu
This paper develops a branch-flow based optimal power flow (OPF) problem for multi-phase distribution networks that allows for tap selection of wye, closed-delta, and open-delta st…
Algorithms for Joint Sensor and Control Nodes Selection in Dynamic Networks
Sebastian A. Nugroho, Ahmad F. Taha, Nikolaos Gatsis +2
The problem of placing or selecting sensors and control nodes plays a pivotal role in the operation of dynamic networks. This paper proposes optimal algorithms and heuristics to so…
Kernel-Based Learning for Smart Inverter Control
Aditie Garg, Mana Jalali, Vassilis Kekatos +1
Distribution grids are currently challenged by frequent voltage excursions induced by intermittent solar generation. Smart inverters have been advocated as a fast-responding means…
A Fixed-Point Iteration for Steady-State Analysis of Water Distribution Networks
Mohammadhafez Bazrafshan, Nikolaos Gatsis, Marcio Giacomoni +1
This paper develops a fixed-point iteration to solve the steady-state water flow equations in an urban water distribution network. The fixed-point iteration is derived upon the ass…
Simultaneous Sensor and Actuator Selection/Placement through Output Feedback Control
Sebastian Nugroho, Ahmad F. Taha, Tyler Summers +1
In most dynamic networks, it is impractical to measure all of the system states; instead, only a subset of the states are measured through sensors. Consequently, and unlike full st…
Vulnerability Analysis of Smart Grids to GPS Spoofing
Paresh Risbud, Nikolaos Gatsis, Ahmad Taha
Sensors such as phasor measurement units (PMUs) endowed with GPS receivers are ubiquitously installed providing real-time grid visibility. A number of PMUs can cooperatively enable…
Dynamic Actuator Selection and Robust State-Feedback Control of Networked Soft Actuators
Nafiseh Ebrahimi, Sebastian Nugroho, Ahmad F. Taha +3
The design of robots that are light, soft, powerful is a grand challenge. Since they can easily adapt to dynamic environments, soft robotic systems have the potential of changing t…
Real-Time Rejection and Mitigation of Time Synchronization Attacks on the Global Positioning System
Ali Khalajmehrabadi, Nikolaos Gatsis, David Akopian +1
This paper introduces the Time Synchronization Attack Rejection and Mitigation (TSARM) technique for Time Synchronization Attacks (TSAs) over the Global Positioning System (GPS). T…
Robust Control for Renewable-Integrated Power Networks Considering Input Bound Constraints and Worst-Case Uncertainty Measure
Ahmad F. Taha, Mohammadhafez Bazrafshan, Sebastian Nugroho +2
Uncertainty from renewable energy and loads is one of the major challenges for stable grid operation. Various approaches have been explored to remedy these uncertainties. In this p…
Time-Varying Sensor and Actuator Selection for Uncertain Cyber-Physical Systems
Ahmad F. Taha, Nikolaos Gatsis, Tyler Summers +1
We propose methods to solve time-varying, sensor and actuator (SaA) selection problems for uncertain cyber-physical systems. We show that many SaA selection problems for optimizing…
Coupling Load-Following Control with OPF
Mohammadhafez Bazrafshan, Nikolaos Gatsis, Ahmad Taha +1
In this paper, the optimal power flow (OPF) problem is augmented to account for the costs associated with the load-following control of a power network. Load-following control cost…
Buildings-to-Grid Integration Framework
Ahmad F. Taha, Nikolaos Gatsis, Bing Dong +2
This paper puts forth a mathematical framework for Buildings-to-Grid (BtG) integration in smart cities. The framework explicitly couples power grid and building's control actions a…