Che-Cheng Chang

Prof. Dr. Che-Cheng Chang

orcid

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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12 November 2021 in Applied Sciences
Verified
Journal Article
Open access
PDF file
CCChe-Cheng Chang
Che-Cheng Chang
JTJichiang Tsai
Jichiang Tsai
JLJun-Han Lin
Jun-Han Lin
YOYee Ming Ooi
Yee Ming Ooi
Recently, autonomous driving has become one of the most popular topics for smart vehicles. However, traditional control strategies are mostly rule-based, which have poor adaptability to the time-varying traffic conditions. Similarly, they have difficulty coping with unexpected situations that may occur any time in the real-world environment. Hence, in this paper, we exploited Deep Reinforcement Learning (DRL) to enhance the quality and safety of autonomous driving control. Based on the road scenes and self-driving simulation modules provided by AirSim, we used the Deep Deterministic Policy Gradient (DDPG) and Recurrent Deterministic Policy Gradient (RDPG) algorithms, combined with the Convolutional Neural Network (CNN), to realize the autonomous driving control of self-driving cars. In particular, by using the real-time images of the road provided by AirSim as the training data, we carefully formulated an appropriate reward-generation method to improve the convergence speed of the adopted DDPG and RDPG models and the control performance of moving driverless cars.

16 August 2021 in IEEE Access
Verified
Journal Article
Open access
CCChe-Cheng Chang
Che-Cheng Chang
YOYee-Ming Ooi
Yee-Ming Ooi
BSBing-Herng Sieh
Bing-Herng Sieh
It is not practical to assume that all vehicles must have the communication ability for the purpose of realizing the IoV-based collision avoidance architecture. Hence, we need some extra designs to make up for the deficiency. In the literature, some researches use a camera mounted on the infrastructure at an intersection to implement the collision detection. Particularly, they utilize the real-time object detection and dynamic prediction to predict the future positions of vehicles for the collision avoidance. In this paper, we propose a new method to predict the future positions of vehicles as well, which is based on a well-known real-time object detection project, YOLOv4. By incorporating the concept of vehicle dynamics with our machine learning architecture, our design can estimate the further future vehicular position more accurately and stably. Lastly, the experimental results show the performance of our algorithm for predicting the future vehicular positions and realizing the collision avoidance architecture.

19 March 2023 in Electronics
Verified
Journal Article
Open access
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TDThanh Hoang Duong
Thanh Hoang Duong
Hsi-Min ChenHsi-Min Chen
Hsi-Min Chen
CCChe-Cheng Chang
Che-Cheng Chang
Autonomous vehicle systems rely heavily upon depth estimation, which facilitates the improvement of precision and stability in automated decision-making systems. Noteworthily, the technique of monocular depth estimation is critical for one of these feasible implementations. In the area of segmentation of medical images, UNet is a well-known encoder–decoder structure. Moreover, several studies have proven its further potential for monocular depth estimation. Similarly, based on UNet, we aim to propose a novel model of monocular depth estimation, which is constructed from the benefits of classical UNet and residual learning mechanisms and named URNet. Particularly, we employ the KITTI dataset in conjunction with the Eigen split strategy to determine the efficacy of our model. Compared with other studies, our URNet is significantly better, on the basis of higher the precision and lower error rate. Hence, it can deal properly with the depth estimation issue for autonomous driving systems.

12 January 2023 in Sensors
Verified
Journal Article
Open access
PDF file
JTJichiang Tsai
Jichiang Tsai
CCChe-Cheng Chang
Che-Cheng Chang
TLTzu Li
Tzu Li
Advanced Driver Assistance Systems (ADAS) are only applied to relatively simple scenarios, such as highways. If there is an emergency while driving, the driver should take control of the car to deal properly with the situation at any time. Obviously, this incurs the uncertainty of safety. Recently, in the literature, several studies have been proposed for the above-mentioned issue via Artificial Intelligence (AI). The achievement is exactly the aim that we look forward to, i.e., the autonomous vehicle. In this paper, we realize the autonomous driving control via Deep Reinforcement Learning (DRL) based on the CARLA (Car Learning to Act) simulator. Specifically, we use the ordinary Red-Green-Blue (RGB) camera and semantic segmentation camera to observe the view in front of the vehicle while driving. Then, the captured information is utilized as the input for different DRL models so as to evaluate the performance, where the DRL models include DDPG (Deep Deterministic Policy Gradient) and RDPG (Recurrent Deterministic Policy Gradient). Moreover, we also design an appropriate reward mechanism for these DRL models to realize efficient autonomous driving control. According to the results, only the RDPG strategies can finish the driving mission with the scenario that does not appear/include in the training scenario, and with the help of the semantic segmentation camera, the RDPG control strategy can further improve its efficiency.

2 August 2022 in Applied Sciences
Verified
Journal Article
Open access
PDF file
JTJichiang Tsai
Jichiang Tsai
CCChe-Cheng Chang
Che-Cheng Chang
YOYu-Cheng Ou
Yu-Cheng Ou
BSBing-Herng Sieh
Bing-Herng Sieh
YOYee Ming Ooi
Yee Ming Ooi
Recently, many artificial intelligence applications in smart cars have been utilized in real life. Making an unmanned ground vehicle (UGV) capable of moving autonomously has become a critical topic. Hence, in this work, a novel method for a UGV to realize path planning and obstacle avoidance is presented using a deep deterministic policy gradient approach (DDPG). More specifically, the lidar sensor mounted on the vehicle is utilized to measure the distance between the vehicle and the surrounding obstacles, and the odometer measures the mileage of the vehicle for the purpose of estimating the current location. Then, the above sensed data are treated as the training data for the DDPG training procedure, and several experiments are performed in different settings utilizing the robot operating system (ROS) and the Gazebo simulator with a real robot module, TurtleBot3, to present a comprehensive discussion. The simulation results show that using the presented design and reward architecture, the DDPG method is better than the classic deep Q-network (DQN) method, e.g., taking fewer steps to reach the goal, less training time to find the smallest number of steps for reaching the goal, and so on.

9 December 2019 in Applied Sciences
Verified
Journal Article
Open access
PDF file
CCChe-Cheng Chang
Che-Cheng Chang
WLWei-Ming Lin
Wei-Ming Lin
CLChuan-An Lai
Chuan-An Lai
For some IoV-based collision-avoidance architectures, it is not necessary that all vehicles have communication abilities. Hence, they need some particular designs and extra components. In the literature, one of them uses a camera mounted onto the infrastructure at an intersection to realize collision detection. Consequently, technologies for real-time object detection and dynamic prediction are required for the purposes of collision avoidance. In this paper, we propose an interesting method to predict the future position of a vehicle based on a well-known, real-time object detection project, YOLOv3. Our algorithm utilizes the concept of vehicle dynamics and the confidence region to predict the future position on vehicles. This will help us to realize real-time dynamic prediction and Internet of Vehicles (IoV)-based collision detection. Lastly, in accordance with the experimental results, our design shows the performance for predicting the future position of a vehicle.