Catastrophic forgetting poses a significant challenge to Federated Class-Incremental Learning (FCIL), leading to performance degradation of continuous tasks in FCIL. To address this issue, an FCIL method of Label Semantic Embedding (LSE) with Multi-Head Self-Attention (MHSA) — ATTLSE (ATTention Label Semantic Embedding) was proposed. Firstly, an LSE with MHSA was integrated with a generator. Secondly, during the stage of Data-Free Knowledge Distillation (DFKD), the generator with MHSA was used to produce more meaningful data samples, which guided the training of client models and reduced the influence of catastrophic forgetting problem in FCIL. Experiments were carried out on the CIFAR-100 and Tiny_ImageNet datasets. The results demonstrate that the average accuracy of ATTLSE is improved by 0.06 to 6.45 percentage points compared to LANDER (Label Text Centered Data-Free Knowledge Transfer) method, so as to solve the catastrophic forgetting problem to certain extent of continuous tasks in FCIL.
As the core of steel production, hot rolling process has demands of strict production continuity and complex production technology. The random arrival of rush orders and urgent delivery requirements have adverse impacts on production continuity and quality stability. Aiming at those kind of dynamic events of rush order insertion, a hot rolling rescheduling optimization method was proposed. Firstly, the influence of order disturbance factor on the scheduling scheme was analyzed, and a mathematical model of hot rolling rescheduling was established with the optimization objective of minimizing the weighted sum of tardiness of orders and jump penalty of slabs. Then, an Estimation of Distribution Algorithm (EDA) for hot rolling rescheduling was designed. In this algorithm, aiming at the insertion processing of rush orders, an integer encoding scheme was proposed based on the insertion position, the probability model based on the characteristics of the model was designed, and the fitness function based on the penalty value was defined by considering the targets and constraints comprehensively. The feasibility and validity of the model and the algorithm were verified by the simulation experiment on the actual production data.
Accurate traffic flow prediction is very important in helping traffic management departments to take effective traffic control and guidance measures and travelers to plan routes reasonably. Aiming at the problem that the traditional deep learning models do not fully consider the spatial-temporal characteristics of traffic data, a CNN-LSTM prediction model based on attention mechanism, namely STCAL (Spatial-Temporal Convolutional Attention-LSTM network), was established under the theoretical frameworks of Convolutional Neural Network (CNN) and Long Short-Term Memory (LSTM) unit and with the combination of the spatial-temporal characteristics of urban traffic flow. Firstly, the fine-grained grid division method was used to construct the spatial-temporal matrix of traffic flow. Secondly, CNN model was used as a spatial component to extract the spatial characteristics of urban traffic flow in different periods. Finally, the LSTM model based on attention mechanism was used as a dynamic time component to capture the temporal characteristics and trend variability of traffic flow, and the prediction of traffic flow was realized. Experimental results show that compared with Gated Recurrent Unit (GRU) and Spatio-Temporal Residual Network (ST-ResNet), STCAL model has the Root Mean Square Error (RMSE) index reduced by 17.15% and 7.37% respectively, the Mean Absolute Error (MAE) index reduced by 22.75% and 9.14% respectively, and the coefficient of determination (R2) index increased by 11.27% and 2.37% respectively. At the same time, it is found that the proposed model has the prediction effect on weekdays with high regularity higher than that on weekends, and has the best prediction effect of morning peak on weekdays, showing that it can provide a basis for short-term urban regional traffic flow change monitoring.
To solve the sensor node localization problem of Wireless Sensor and Actor Network (WSAN), a range-based localization algorithm with virtual force in WSAN was proposed in this paper, in which mobile actor nodes were used instead of Wireless Sensor Network (WSN) anchors for localization algorithm, and Time Of Arrival (TOA) was combined with virtual force. In this algorithm, the actor nodes were driven under the action of virtual force and made themself move close to the sensor node which sent location request, and node localization was completed by the calculation of the distance between nodes according to the signal transmission time. The simulation results show that the localization success rate of the proposed algorithm can be improved by 20% and the average localization time and cost are less than the traditional TOA algorithm. It can apply to real-time field with small number of actor nodes.