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Open Access Issue
A Dynamic and Deadline-Oriented Road Pricing Mechanism for Urban Traffic Management
Tsinghua Science and Technology 2022, 27(1): 91-102
Published: 17 August 2021
Abstract PDF (6.7 MB) Collect
Downloads:91

Road pricing is an urban traffic management mechanism to reduce traffic congestion. Currently, most of the road pricing systems based on predefined charging tolls fail to consider the dynamics of urban traffic flows and travelers’ demands on the arrival time. In this paper, we propose a method to dynamically adjust online road toll based on traffic conditions and travelers’ demands to resolve the above-mentioned problems. The method, based on deep reinforcement learning, automatically allocates the optimal toll for each road during peak hours and guides vehicles to roads with lower toll charges. Moreover, it further considers travelers’ demands to ensure that more vehicles arrive at their destinations before their estimated arrival time. Our method can increase the traffic volume effectively, as compared to the existing static mechanisms.

Open Access Issue
Event Temporal Relation Extraction with Attention Mechanism and Graph Neural Network
Tsinghua Science and Technology 2022, 27(1): 79-90
Published: 17 August 2021
Abstract PDF (3 MB) Collect
Downloads:117

Event temporal relation extraction is an important part of natural language processing. Many models are being used in this task with the development of deep learning. However, most of the existing methods cannot accurately obtain the degree of association between different tokens and events, and event-related information cannot be effectively integrated. In this paper, we propose an event information integration model that integrates event information through multilayer bidirectional long short-term memory (Bi-LSTM) and attention mechanism. Although the above scheme can improve the extraction performance, it can still be further optimized. To further improve the performance of the previous scheme, we propose a novel relational graph attention network that incorporates edge attributes. In this approach, we first build a semantic dependency graph through dependency parsing, model a semantic graph that considers the edges’ attributes by using top-k attention mechanisms to learn hidden semantic contextual representations, and finally predict event temporal relations. We evaluate proposed models on the TimeBank-Dense dataset. Compared to previous baselines, the Micro-F1 scores obtained by our models improve by 3.9% and 14.5%, respectively.

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