Junhua Zhao

Dr. Junhua Zhao


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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22 March 2016 in IEEE Transactions on Smart Grid
Verified
Journal Article
Closed access
Gaoqi LiangGaoqi Liang
Gaoqi Liang
JZJunhua Zhao
Junhua Zhao
FLFengji Luo
Fengji Luo
SWSteven R. Weller
Steven R. Weller
Zhaoyang DongZhaoyang Dong
Zhaoyang Dong
With rapid advances in sensor, computer, and communication networks, modern power systems have become complicated cyber-physical systems. Assessing and enhancing cyber-physical system security is, therefore, of utmost importance for the future electricity grid. In a successful false data injection attack (FDIA), an attacker compromises measurements from grid sensors in such a way that undetected errors are introduced into estimates of state variables such as bus voltage angles and magnitudes. In evading detection by commonly employed residue-based bad data detection tests, FDIAs are capable of severely threatening power system security. Since the first published research on FDIAs in 2009, research into FDIA-based cyber-attacks has been extensive. This paper gives a comprehensive review of state-of-the-art in FDIAs against modern power systems. This paper first summarizes the theoretical basis of FDIAs, and then discusses both the physical and the economic impacts of a successful FDIA. This paper presents the basic defense strategies against FDIAs and discusses some potential future research directions in this field.

25 November 2024 in IEEE Transactions on Neural Networks and Learning Systems
Verified
Journal Article
Closed access
YCYuji Cao
Yuji Cao
HZHuan Zhao
Huan Zhao
YCYuheng Cheng
Yuheng Cheng
TSTing Shu
Ting Shu
YCYue Chen
Yue Chen
YLYun Li
Yun Li
With extensive pretrained knowledge and high-level general capabilities, large language models (LLMs) emerge as a promising avenue to augment reinforcement learning (RL) in aspects, such as multitask learning, sample efficiency, and high-level task planning. In this survey, we provide a comprehensive review of the existing literature in LLM-enhanced RL and summarize its characteristics compared with conventional RL methods, aiming to clarify the research scope and directions for future studies. Utilizing the classical agent–environment interaction paradigm, we propose a structured taxonomy to systematically categorize LLMs’ functionalities in RL, including four roles: information processor, reward designer, decision-maker, and generator. For each role, we summarize the methodologies, analyze the specific RL challenges that are mitigated and provide insights into future directions. Finally, the comparative analysis of each role, potential applications, prospective opportunities, and challenges of the LLM-enhanced RL are discussed. By proposing this taxonomy, we aim to provide a framework for researchers to effectively leverage LLMs in the RL field, potentially accelerating RL applications in complex applications, such as robotics, autonomous driving, and energy systems.

21 November 2016 in IEEE Transactions on Smart Grid
Verified
Journal Article
Closed access
WKWeicong Kong
Weicong Kong
Zhaoyang DongZhaoyang Dong
Zhaoyang Dong
JMJin Ma
Jin Ma
DHDavid J. Hill
David J. Hill
JZJunhua Zhao
Junhua Zhao
FLFengji Luo
Fengji Luo
Appliance-level load models are expected to be crucial to future smart grid applications. Unlike direct appliance monitoring approaches, it is more flexible and convenient to mine smart meter data to generate load models at device level nonintrusively and generalise to all households with smart meter ownership. This paper proposes a comprehensive and extensible framework to solve the load disaggregation problem for residential households. Our approach examines both the modelling of home appliances as hidden Markov models and the solving of non-intrusive load monitoring based on segmented integer quadratic constraint programming to disaggregate a household power profile into the appliance level. Structure of our approach to be implemented with current smart meter infrastructure is given and simulations are performed based on public datasets. All data are down-sampled to the rate that is consistent with the Australia smart meter infrastructure minimum functionality. The results demonstrate that our approach is able to work with existing smart meters to generate device level load model for other smart grid research and applications.

14 February 2020 in IEEE Transactions on Industrial Informatics
Verified
Journal Article
Closed access
HZHuan Zhao
Huan Zhao
JZJunhua Zhao
Junhua Zhao
JQJing Qiu
Jing Qiu
GLGaoqi Liang
Gaoqi Liang
Zhaoyang DongZhaoyang Dong
Zhaoyang Dong
Cooperative wind farm control is a complex problem due to wake effect, and it is hard to find the proper model. Reinforcement learning can find the optimal policy in a dynamic environment using “trial and error,” but may damage the machine and cause high cost during the learning process. In order to address this challenge, this article proposes the knowledge-assisted reinforcement learning framework by combining the low-fidelity analytical model with a reinforcement learning framework. Moreover, the knowledge-assisted deep deterministic policy gradient (KA-DDPG) algorithm and three kinds of knowledge-assisted learning methods are proposed based on the framework. The proposed methods are tested in nine different scenarios of WFSim. The simulation results show that the KA-DDPG algorithm can reach the maximum power output and ensure safety during learning. In addition, the learning cost is reduced by accelerating the learning process.

10 April 2018 in IEEE Transactions on Smart Grid
Verified
Journal Article
Closed access
Jiajia YangJiajia Yang
Jiajia Yang
JZJunhua Zhao
Junhua Zhao
FWFushuan Wen
Fushuan Wen
Zhaoyang DongZhaoyang Dong
Zhaoyang Dong
The problem of customizing electricity retail prices using data mining techniques is studied in this paper. The density-based spatial clustering of applications with noise (DBSCAN) is firstly applied to load profile analysis, in order to explore end-users’ inherent electricity consumption patterns from their historical load data. Then, statistical analysis of end-users’ historical consumption is conducted to better capture their consumption regularity. After extracting these load features, a mixed integer nonlinear programming (MINLP) model for customizing electricity retail prices is proposed. In the proposed model, both the structure of TOU retail price and the price level are optimized once given the number of price blocks. It is among the first that the optimization of TOU price structure is studied in electricity retail pricing research. The proposed model is mathematically reformulated and solved by online commercial solvers provided by the NEOS (Net-work-Enabled Optimization System) server. Electricity usage data collected by the Smart Grid, Smart City (SGSC) project in Australia is used to demonstrate the feasibility and efficiency of the developed models and algorithms.

10 January 2017 in IEEE Transactions on Smart Grid
Verified
Journal Article
Closed access
Jiajia YangJiajia Yang
Jiajia Yang
JZJunhua Zhao
Junhua Zhao
FLFengji Luo
Fengji Luo
FWFushuan Wen
Fushuan Wen
Zhaoyang DongZhaoyang Dong
Zhaoyang Dong
With the continuous development of smart grid and further restructuring of power industry, modern power systems have been transformed to complex cyber-physical systems characterized with high renewable energy penetrations, distributed facilities, advanced metering, and communication technologies, as well as ever-increasing customer awareness. These new development trends pose significant challenges for electricity retailers and call for innovative decision-making methods. To help researchers and engineers have a better overview of the state-of-the-art on electricity retail decision-making schemes, this paper aims to survey the latest progress on this subject. Some critical and open issues in this field are also discussed.