DJ Ning

Prof. DJ Ning

Smart Ciry Research Center, Shanghai Advanced Research Institute, Pudong, Shanghai, China
orcid

Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

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

Representative Publications

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25 May 2020 in Applied Sciences
Verified
Journal Article
Open access
PDF file
YWYu Wang
Yu Wang
DNDJ Ning
DJ Ning
SFSonglin Feng
Songlin Feng
In the prognostics health management (PHM) of rotating machinery, the accurate identification of bearing fault is critical. In recent years, various deep learning methods can well identify bearing fault based on monitoring data. However, facing changing operating conditions and noise pollution, the accuracy of these algorithms decreases significantly, which makes the algorithms difficult in practical applications. To solve this problem, a novel capsule network based on wide convolution and multi-scale convolution (WMSCCN) is proposed for fault diagnosis. The proposed WMSCCN algorithm takes one-dimensional vibration signal as an input and no additional manual processing is required. In addition, the adaptive batch normalization (AdaBN) algorithm is introduced to further enhance the adaptability of WMSCCN under noise pollution and load changes. On generalization experiments under different loads, the proposed WMSCCN and WMSCCN-AdaBN algorithms achieve average accuracy rates of 96.44% and 97.44%, respectively, which is superior to other advanced algorithms. In the noise resistance experiment, the proposed WMSCCN-AdaBN can maintain a 92.3% diagnostic accuracy in a strong noise environment with a signal to noise ratio (SNR) = −4 dB, showing a very strong anti-noise ability. When the SNR exceeds 4 dB, the accuracy reaches 100%, indicating that the proposed algorithm has a very good accuracy at low noise levels. Two experiments have effectively verified the validity and generalizability of the proposed model.

6 December 2022 in Applied Sciences
Verified
Journal Article
Open access
PDF file
JMJue Ma
Jue Ma
DNDJ Ning
DJ Ning
CZChengyi Zhang
Chengyi Zhang
SLShipeng Liu
Shipeng Liu
Prioritized experience replay (PER) is an important technique in deep reinforcement learning (DRL). It improves the sampling efficiency of data in various DRL algorithms and achieves great performance. PER uses temporal difference error (TD-error) to measure the value of experiences and adjusts the sampling probability of experiences. Although PER can sample valuable experiences according to the TD-error, freshness is also an important character of experiences. It implicitly reflects the potential value of experiences. Fresh experiences are produced by virtue of the current networks and they are more valuable for updating the current network parameters than the past. The sampling of fresh experiences to train the neural networks can increase the learning speed of the agent, but few algorithms can perform this job efficiently. To solve this issue, a novel experience replay method is proposed in this paper. We first define that the experience freshness is negatively correlated with the number of replays. A new hyper-parameter, the freshness discounted factor μ, is introduced in PER to measure the experience freshness. Further, a novel experience replacement strategy in the replay buffer is proposed to increase the experience replacement efficiency. In our method, the sampling probability of fresh experiences is increased by raising its priority properly. So the algorithm is more likely to choose fresh experiences to train the neural networks during the learning process. We evaluated this method in both discrete control tasks and continuous control tasks via OpenAI Gym. The experimental results show that our method achieves better performance in both modes of operation.

17 February 2023 in Applied Sciences
Verified
Journal Article
Open access
PDF file
SLShipeng Liu
Shipeng Liu
DNDJ Ning
DJ Ning
JMJue Ma
Jue Ma
Despite the growing capabilities of the short-term prediction of photovoltaic power, we still face two challenges to longer time-range predictions: error accumulation and long-term time series feature extraction. In order to improve the longer time range prediction accuracy of photovoltaic power, this paper proposes a seq2seq prediction model TCNformer, which outperforms other state-of-the-art (SOTA) algorithms by introducing variable selection (VS), long- and short-term time series feature extraction (LSTFE), and one-step temporal convolutional network (TCN) decoding. A VS module employs correlation analysis and periodic analysis to separate the time series correlation information, LSTFE extracts multiple time series features from time series data, and one-step TCN decoding realizes generative predictions. We demonstrate here that TCNformer has the lowest mean squared error (MSE), mean absolute error (MAE) and mean absolute percentage error (MAPE) in contrast to the other algorithms in the field of the short-term prediction of photovoltaic power, and furthermore, the effectiveness of each module has been verified through ablation experiments.

4 April 2022 in Neural Processing Letters
Verified
Journal Article
Closed access
PDF file
YWYu Wang
Yu Wang
DNDJ Ning
DJ Ning
JLJunzhe Lu
Junzhe Lu

5 May 2023 in Energies
Verified
Journal Article
Open access
PDF file
XCXihui Chen
Xihui Chen
DNDJ Ning
DJ Ning
In a smart home with distributed energy resources, the home energy management system (HEMS) controls the photovoltaic (PV) storage system by executing the optimization algorithm to achieve the lowest power cost. The existing mixed integer linear programming (MILP) algorithm is not suitable for execution on the end-user side due to its high computational complexity. The HEMS algorithm based on a long short-term memory neural network (LSTM-HEMS) can effectively solve the problem of the high computational complexity of MILP, but its optimization outcome is not high due to the accumulation of prediction errors. In order to achieve a better balance between computational complexity and optimization outcome, this paper proposes a lightweight optimization algorithm called the FastInformer-HEMS, which introduces the E-Attn attention mechanism based on Informer and uses global average pooling to extract the attention characteristics. Meanwhile, the proposed method introduces the maximum self-consumption algorithm as a backup strategy to ensure the safe operation of the system. The simulated results show that the computational complexity of the proposed FastInformer-HEMS is the lowest among the existing algorithms. Compared with the existing LSTM-HEMS, the proposed algorithm reduces the power consumption cost by 12.3% and 6.6% in the two typical scenarios, while the execution time decreases by 13.6 times.

11 September 2024 in Trends in Computer Science and Information Technology
Verified
Journal Article
Open access
PDF file
YLYutong Lai
Yutong Lai
JBJunqi Bai
Junqi Bai
YYYuxuan You
Yuxuan You
DNDJ Ning
DJ Ning
In recent years, Large Language Models (LLMs) with massive parameters and complex structures have achieved significant breakthroughs in fields such as natural language processing and image generation, driving their widespread application in industrial sectors. Despite the enormous potential of industrial AI models in areas like design and development, monitoring and management, quality control, and maintenance, their actual construction and deployment still face a lot of challenges, including inherent model deficiencies and difficulties in aligning with industrial requirements. Future technological development trends include the generation of customized industrial datasets, the collaborative optimization of large and small models, the enhancement of adaptive capabilities, and the application of Retrieval-Augmented Generation (RAG) technology. These trends are expected to improve the effectiveness and scalability of AI models, better meeting the needs of the industrial domain. This paper systematically discusses the challenges, technological development trends, and practical applications and deployment of industrial AI models, providing valuable insights for future directions.