Tong Liu

Dr. Tong Liu


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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14 March 2022 in IEEE Transactions on Neural Networks and Learning Systems
Verified
Journal Article
Closed access
Honghao GaoHonghao Gao
Honghao Gao
JXJunsheng Xiao
Junsheng Xiao
YYYuyu Yin
Yuyu Yin
TLTong Liu
Tong Liu
JSJiangang Shi
Jiangang Shi
Fully supervised semantic segmentation has performed well in many computer vision tasks. However, it is time-consuming because training a model requires a large number of pixel-level annotated samples. Few-shot segmentation has recently become a popular approach to addressing this problem, as it requires only a handful of annotated samples to generalize to new categories. However, the full utilization of limited samples remains an open problem. Thus, in this article, a mutually supervised few-shot segmentation network is proposed. First, the feature maps from intermediate convolution layers are fused to enrich the capacity of feature representation. Second, the support image and query image are combined into a bipartite graph, and the graph attention network is adopted to avoid losing spatial information and increase the number of pixels in the support image to guide the query image segmentation. Third, the attention map of the query image is used as prior information to enhance the support image segmentation, which forms a mutually supervised regime. Finally, the attention maps of the intermediate layers are fused and sent into the graph reasoning layer to infer the pixel categories. Experiments are conducted on the PASCAL VOC- $5^i$ dataset and FSS-1000 dataset, and the results demonstrate the effectiveness and superior performance of our method compared with other baseline methods.

4 February 2022 in IEEE Transactions on Mobile Computing
Verified
Journal Article
Closed access
TLTong Liu
Tong Liu
SNShenggang Ni
Shenggang Ni
XLXiaoqiang Li
Xiaoqiang Li
Yanmin ZhuYanmin Zhu
Yanmin Zhu
LKLinghe Kong
Linghe Kong
YYYuanyuan Yang
Yuanyuan Yang
Due to the urgent emergence of computation-intensive intelligent applications on end devices, edge computing has been put forward as an extension of cloud computing, to satisfy the low-latency requirements of these applications. To process heterogenous computation tasks on an edge node, the corresponding services should be placed in advance, including installing softwares and caching databases/libraries. Considering the limited storage space and computation resources on the edge node, services should be elaborately selected and deployed on the edge node and its computation resources should be carefully allocated to placed services, according to the arrivals of computation workloads. The joint service placement and computation resource allocation problem is particularly complicated, in terms of considering the stochastic arrivals of tasks, the additional latency incurred by service migration, and the waiting time of unprocessed tasks. Benefiting from deep reinforcement learning, we propose a novel approach based on parameterized deep Q networks to make the joint service placement and computation resource allocation decisions, with the objective of minimizing the total latency of tasks in a long term. Extensive simulations are conducted to evaluate the convergence and performance achieved by our proposed approach.

3 May 2022 in IEEE Transactions on Intelligent Transportation Systems
Verified
Journal Article
Closed access
Honghao GaoHonghao Gao
Honghao Gao
WHWanqiu Huang
Wanqiu Huang
TLTong Liu
Tong Liu
YYYuyu Yin
Yuyu Yin
YLYouhuizi Li
Youhuizi Li
AI-empowered 5G/6G networks play a substantial role in taking full advantage of the Internet of Things (IoT) to perform complex computing by offloading tasks to edge services deployed in intelligent transport systems. However, offloading behavior has a certain regularity, and the real-time location of users can easily be inferred by attackers who have historical user data during the data transmission process. To address this problem, a privacy-oriented task offloading method that can resist attacks from privacy attackers with prior knowledge is proposed. First, the local computing model, channel model, and privacy loss model are defined and used to quantify evaluation indicators, such those related to privacy, time, and energy. Among them, privacy loss is formalized as the probability of a successful attack by an attacker with prior knowledge. Second, the process of solving an optimal task offloading decision problem is formalized into a Markov decision process (MDP). Finally, the deep reinforcement learning (DRL) method PPO2 is proposed to solve the planning problem of task offloading with good generalization and convergence speed, where we focus on the location privacy requirement. Experiments show that our method can handle large-scale task offloading and obtain offloading policies with reduced privacy loss, energy consumption and time delays.

13 January 2021 in IEEE Internet of Things Journal
Verified
Journal Article
Closed access
TLTong Liu
Tong Liu
YZYameng Zhang
Yameng Zhang
Yanmin ZhuYanmin Zhu
Yanmin Zhu
WTWeiqin Tong
Weiqin Tong
YYYuanyuan Yang
Yuanyuan Yang
With the explosion of mobile smart devices, many computation intensive applications have emerged, such as interactive gaming and augmented reality. Mobile-edge computing (EC) is put forward, as an extension of cloud computing, to meet the low-latency requirements of the applications. In this article, we consider an EC system built in an ultradense network with numerous base stations. Heterogeneous computation tasks are successively generated on a smart device moving in the network. An optimal task offloading strategy, as well as optimal CPU frequency and transmit power scheduling, is desired by the device user to minimize both task completion latency and energy consumption in a long term. However, due to the stochastic task generation and dynamic network conditions, the problem is particularly difficult to solve. Inspired by reinforcement learning, we transform the problem into a Markov decision process. Then, we propose an attention-based double deep Q network (DDQN) approach, in which two neural networks are employed to estimate the cumulative latency and energy rewards achieved by each action. Moreover, a context-aware attention mechanism is designed to adaptively assign different weights to the values of each action. We also conduct extensive simulations to compare the performance of our proposed approach with several heuristic and DDQN-based baselines.

17 December 2020 in IEEE Transactions on Mobile Computing
Verified
Journal Article
Closed access
TLTong Liu
Tong Liu
LFLu Fang
Lu Fang
Yanmin ZhuYanmin Zhu
Yanmin Zhu
WTWeiqin Tong
Weiqin Tong
YYYuanyuan Yang
Yuanyuan Yang
Due to the explosion of mobile devices and the evolution of wireless communication technologies, novel applications with intensive computation demands and low-latency requirements have arisen. Edge computing has been proposed as an extension of cloud computing, which moves computation workloads from remote cloud to network edge. Cooperating edge computing and cloud computing can significantly reduce the latency of computation tasks. However, considering the heterogeneity and stochastic arrivals of tasks and the limited computation and communication resources on the edge, task offloading and resource allocation are two joint crucial problems in an edge-cloud orchestrated computing system. In this paper, we propose an online task offloading and resource allocation approach for edge-cloud orchestrated computing, with the aim to minimize the average latency of tasks over time. We first build system models to analyze the latency and energy consumption incurred under different computing modes and formally formulate the joint problem as a mixed-integer optimal decision problem. Then, we employ Lyapunov optimization and duality theory to decompose the problem into a set of subproblems, which can be solved in a semi-decentralized way. We also formally analyze that our approach can achieve near-optimal performance. Extensive simulations are conducted to verify the superiority of our approach.

5 September 2019 in IEEE Internet of Things Journal
Verified
Journal Article
Closed access
TLTong Liu
Tong Liu
Yanmin ZhuYanmin Zhu
Yanmin Zhu
YYYuanyuan Yang
Yuanyuan Yang
FYFan Ye
Fan Ye
As the development of metropolises, air pollution has become a serious problem recently, especially in developing countries like China. Many governments and researchers have devoted themselves to tackling and solving this problem. With the proliferation of smartphones, mobile crowdsensing is becoming a promising paradigm for monitoring large-scale environmental phenomena. In a practical crowdsensing system, incentives should be provided to encourage the participation of rational smartphone users, because it incurs various costs on users to collect sensing data. However, monitoring fine-grained air pollution in a large urban area based on crowdsensing will lead to high payments, which makes designing an efficient incentive mechanism be a challenging problem. Fortunately, compressive sensing has been proved as an effective technology to reduce the amount of collected data via exploiting the spatial correlations among sensing data. In this work, we employ compressive sensing in the air pollution monitoring application, in which only a sampled set of locations are selected to collect data and provide incentives to participants, and air pollution concentrations in unselected locations are inferred via compressive sensing. We propose an active learning scheme, which iteratively selects valuable locations to collect sensing data. Moreover, an expectation maximization based algorithm is designed to detect the contexts in which sensing data are collected, and an efficient incentive mechanism is provided to encourage users with low costs participating. Comprehensive simulations are conducted to demonstrate the performance of our proposed scheme.