Multi-objective particle swarm optimization algorithm for multi-step electric load forecasting

As energy saving becomes more and more popular, electric load forecasting has played a more and more crucial role in power management systems in the last few years. Because of the real-time characteristic of electricity and the uncertainty change of an electric load, realizing the accuracy and stability of electric load forecasting is a challenging task. Many predecessors have obtained the expected forecasting results by various methods. Considering the stability of time series prediction, a novel combined electric load forecasting, which based on extreme learning machine (ELM), recurrent neural network (RNN), and support vector machines (SVMs), was proposed. The combined model first uses three neural networks to forecast the electric load data separately considering that the single model has inevitable disadvantages, the combined model applies the multi-objective particle swarm optimization algorithm (MOPSO) to optimize the parameters. In order to verify the capacity of the proposed combined model, 1-step, 2-step, and 3-step are used to forecast the electric load data of three Australian states, including New South Wales, Queensland, and Victoria. The experimental results intuitively indicate that for these three datasets, the combined model outperforms all three individual models used for comparison, which demonstrates its superior capability in terms of accuracy and stability

Defect electrocatalytic mechanism: concept, topological structure and perspective

Carbon-based materials have been attracting intense interest for electrocatalysis due to their various merits, such as abundance, low cost, high conductivity and tunable molecular structures. However, to date, the electrochemical activities of these electrocatalysts are mainly attributed to different active dopants (e.g. N, B, P or S), leading to a common concept that heteroatom doping is essential for carbon-based electrocatalysts. Recently, we presented a new concept where the specific topological defects could activate the oxygen reduction reaction (ORR) and developed a facile method to create such unique defects. Subsequent research has extended this new mechanism to other reactions, such as the hydrogen and oxygen evolution reactions (HER and OER) and confirmed that heteroatom doping is not essential but that these defects can serve as actives sites for electrochemical reactions. This new theory then creates a new research direction in electrocatalysis. In this short review, we summarise the origin and presentation of the defect mechanism concept, the possible topological defect structures that are effective for electrochemical reactions, the formation of desirable defects, the challenges in the synthesis and characterization of typical defects and future research directions on the electrochemical defect mechanism

DIFFERENCES BETWEEN MALE AND FEMALE PLAYERS IN THE SAGITTAL PLANE BIOMECHANICS DURING VOLLEYBALL SPIKE LANDING

The purpose of this study was to investigate the kinematics and kinetics differences between male and female players after a volleyball spike landing. Eight male and eight female university volleyball players were recruited to participate in this study. The kinematic and kinetic data were collected by ten Vicon cameras (300 Hz) and two force plates (1500 Hz). The Visual 3D software was used to analyze the kinematic and kinetic variables. The results indicated that male players exhibited greater peak hip flexion angle, hip range of motion and hip extensor moment compared with female players. Female players exhibited greater peak ankle dorsiflexion and ankle range of motion than male players. These differences demonstrated that male and female players performed different strategies during volleyball spike landing

THE EFFECT OF SIDE STEP ON LOWER EXTREMITY BIOMECHANICS DURING BLOCK LANDING IN FEMALE VOLLEYBALL PLAYERS

The purpose of this study was to examine the effect of block and side step block on lower extremity biomechanics during landing in female volleyball players. Eight female university volleyball players participated in this study. The kinematic and kinetic data were collected by eight Vicon cameras (250 Hz) and two force plates (1000 Hz). The Visual 3D software was used to analyze the kinematic and kinetic of block and side step block landing variables. The results showed a significantly higher knee extensor moment during side step landing than the block landing at the time of peak vertical ground reaction force and peak joint moment. It was concluded that female players displayed greater knee extensor moment during the side step before block landing that may increase the loading on the knee