Haijun Liao

Dr. Haijun Liao


Research Focus & Metrics

Academic Career Length

8Years (2019-Present)

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

Representative Publications

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21 December 2021 in IEEE Transactions on Industrial Informatics
Verified
Journal Article
Closed access
Zhenyu ZhouZhenyu Zhou
Zhenyu Zhou
ZJZehan Jia
Zehan Jia
HLHaijun Liao
Haijun Liao
WLWenbing Lu
Wenbing Lu
Shahid MumtazShahid Mumtaz
Shahid Mumtaz
Muhammad TariqMuhammad Tariq
Muhammad Tariq
Digital twin (DT) provides accurate guidance for multidimensional resource scheduling in 5G edge computing-empowered distribution grids by establishing a digital representation of the physical entities. In this article, we address the critical challenges of DT construction and DT-assisted resource scheduling such as low accuracy, large iteration delay, and security threats. We propose a federated learning-based DT framework and present a Secure and lAtency-aware dIgital twin assisted resource scheduliNg algoriThm (SAINT). SAINT achieves low-latency, accurate, and secure DT by jointly optimizing its total iteration delay and loss function, and leveraging abnormal model recognition (AMR). SAINT enables intelligent resource scheduling by using DT to improve the learning performance of deep Q-learning. SAINT supports access priority and energy consumption awareness due to the consideration of long-term constraints. Compared with state-of-the-art algorithms, SAINT has superior performance in cumulative iteration delay, DT loss function, energy consumption, and access priority deficit.

9 February 2021 in IEEE Internet of Things Journal
Verified
Journal Article
Closed access
HLHaijun Liao
Haijun Liao
Zhenyu ZhouZhenyu Zhou
Zhenyu Zhou
Xiongwen ZhaoXiongwen Zhao
Xiongwen Zhao
YWYang Wang
Yang Wang
Space-air-ground-integrated power Internet of Things (SAG-PIoT) can provide ubiquitous communication and computing services for PIoT devices deployed in remote areas. In SAG-PIoT, the tasks can be either processed locally by PIoT devices, offloaded to edge servers through unmanned aerial vehicles (UAVs), or offloaded to cloud servers through satellites. However, the joint optimization of task offloading and computational resource allocation faces several challenges, such as incomplete information, dimensionality curse, and coupling between long-term constraints of queuing delay and short-term decision making. In this article, we propose a learning-based queue-aware task offloading and resource allocation algorithm (QUARTER). Specifically, the joint optimization problem is decomposed into three deterministic subproblems: 1) device-side task splitting and resource allocation; 2) task offloading; and 3) server-side resource allocation. The first subproblem is solved by the Lagrange dual decomposition. For the second subproblem, we propose a queue-aware actor-critic-based task offloading algorithm to cope with dimensionality curse. A greedy-based low-complexity algorithm is developed to solve the third subproblem. Compared with existing algorithms, simulation results demonstrate that QUARTER has superior performances in energy consumption, queuing delay, and convergence.

29 July 2022 in IEEE Transactions on Industrial Informatics
Verified
Journal Article
Closed access
HLHaijun Liao
Haijun Liao
Zhenyu ZhouZhenyu Zhou
Zhenyu Zhou
NLNian Liu
Nian Liu
YZYan Zhang
Yan Zhang
GXGuangyuan Xu
Guangyuan Xu
Shahid MumtazShahid Mumtaz
Shahid Mumtaz
The real-time electrical equipment management such as renewable energy, controllable loads, and storage units, plays a key role in low-carbon operation of smart industrial park. Digital twin (DT) which explores cloud-edge-device collaboration and artificial intelligence to establish accurate digital representation of physical equipment is a cutting-edge technology to realize intelligent optimization of electrical equipment management. However, the practical implementation still faces reliability and communication efficiency problems, such as adverse impact of electromagnetic interference on DT reliability, high communication cost of DT model training, and uncoordinated resource allocation among cloud, edge, and device layers. We propose a Cloud-edge-device Collaborative reliable and Communication-efficient DT for lOW-carbon electrical equipment management named $\text{C}^{3}$-FLOW. It minimizes the long-term global loss function and time-average communication cost by jointly optimizing device scheduling, channel allocation, and computational resource allocation. Simulation results verify that $\text{C}^{3}$-FLOW performs superior in loss function, communication efficiency, and carbon emission reduction.

4 July 2019 in IEEE Transactions on Vehicular Technology
Verified
Journal Article
Closed access
Zhenyu ZhouZhenyu Zhou
Zhenyu Zhou
HLHaijun Liao
Haijun Liao
Xiongwen ZhaoXiongwen Zhao
Xiongwen Zhao
BABo Ai
Bo Ai
Mohsen GuizaniMohsen Guizani
Mohsen Guizani
Vehicular fog computing (VFC) has emerged as a cost-efficient solution for task processing in vehicular networks. However, how to realize effective server recruitment and reliable task offloading under information asymmetry and uncertainty remains a critical challenge. In this paper, we adopt a two-stage task offloading framework to address this challenge. Firstly, we propose a convex-concave procedure (CCP)-based contract optimization algorithm for server recruitment, which aims to maximize the expected utility of the operator with asymmetric information. Then, a low-complexity and stable task offloading mechanism is proposed to minimize the total network delay based on the pricing-based matching. Furthermore, we extend the work to the scenario of information uncertainty, and develop a matching-learning-based task offloading mechanism, which takes both occurrence awareness and conflict awareness into consideration. Simulation results demonstrate that the proposed algorithm can effectively motivate resource sharing and guarantee bounded deviation from the optimal performance without the global information.

4 September 2020 in IEEE Journal on Selected Areas in Communications
Verified
Journal Article
Closed access
ZZZhenyu Zhou
Zhenyu Zhou
ZWZhao Wang
Zhao Wang
HYHaijun Yu
Haijun Yu
HLHaijun Liao
Haijun Liao
SMShahid Mumtaz
Shahid Mumtaz
Valerio FrascollaValerio Frascolla
Valerio Frascolla
In the Internet of Health Things (IoHT)-based e-Health paradigm, a large number of computational-intensive tasks have to be offloaded from resource-limited IoHT devices to proximal powerful edge servers to reduce latency and improve energy efficiency. However, the lack of global state information (GSI), the adversarial competition among multiple IoHT devices, and the ultra reliable and low latency communication (URLLC) constraints have imposed new challenges for task offloading optimization. In this paper, we formulate the task offloading problem as an adversarial multi-armed bandit (MAB) problem. In addition to the average-based performance metrics, bound violation probability, occurrence probability of extreme events, and statistical properties of excess values are employed to characterize URLLC constraints. Then, we propose a URLLC-aware Task Offloading scheme based on the exponential-weight algorithm for exploration and exploitation (EXP3) named UTO-EXP3. URLLC awareness is achieved by dynamically balancing the URLLC constraint deficits and energy consumption through online learning. We provide a rigorous theoretical analysis to show that guaranteed performance with a bounded deviation can be achieved by UTO-EXP3 based on only local information. Finally, the effectiveness and reliability of UTO-EXP3 are validated through simulation results.

21 July 2020 in IEEE Transactions on Intelligent Transportation Systems
Verified
Journal Article
Closed access
HLHaijun Liao
Haijun Liao
YMYansong Mu
Yansong Mu
Zhenyu ZhouZhenyu Zhou
Zhenyu Zhou
MSMeng Sun
Meng Sun
ZWZhao Wang
Zhao Wang
CPChao Pan
Chao Pan
Vehicular fog computing has emerged as a complementary framework for edge computing by leveraging the under-utilized computational resources of vehicles. However, how to reduce task offloading delay, queuing delay, and handover cost with incomplete information while simultaneously ensuring privacy, fairness, and security remains an open issue. In this paper, we develop a secure and intelligent task offloading framework to address these challenges. We exploit blockchain and smart contract to facilitate fair task offloading and mitigate various security attacks. Then, we design a subjective logic-based trustfulness metric to quantify the possibility of task offloading success, and develop a trustfulness assessment mechanism. An online learning-based intelligent task offloading algorithm named QUeuing-delay aware, handOver-cost aware, and Trustfulness Aware Upper Confidence Bound (QUOTA-UCB) is proposed, which can learn the long-term optimal strategy and achieve a well-balanced tradeoff among task offloading delay, queuing delay, and handover cost. Finally, extensive theoretical analysis and simulations are carried out to demonstrate the reliability, feasibility, and efficiency of the proposed secure and intelligent task offloading scheme.