Reform and Practice of Immersive Teaching in Environmental Acoustics

Environmental Acoustics is a professional course that educates students majoring in Acoustics. Affected by practical equipment and other factors, the teaching effect of knowledge points relevant to subjective auditory perception contained in the course is poor. Taking the course of Spatial Hearing and 3D Stereo as an example, this study develops a virtual simulation experiment system for the topic of subjective hearing perception in order to carry out the reform and practice of immersive teaching. Combined with the virtual simulation experiment project with high sense of presence, students are supported by the actual auditory perception effect in the whole learning process and have achieved good learning effect.

Wide-Field Telescope Alignment Using the Model-Based Method Combined with the Stochastic Parallel Gradient Descent Algorithm

To acquire images with higher accuracy of wide-field telescopes, deformable mirrors with more than 100 actuators are used, making the telescope alignment more complex and time-consuming. Furthermore, the position of the obscuration caused by the secondary mirror in the experiment system is changed with the difference of fields of view, making the response matrix of the deformable mirror different in various fields of view. To solve this problem, transfer functions corresponding to different fields of view are calculated according to the wavefront edge check and boundary conditions. In this paper, a model-based method combined with the stochastic parallel gradient descent (SPGD) algorithm is used. The experiment results show that our method can correct the aberrations with a high accuracy in both on-axis and off-axis fields, indicating that the effective actuators are well chosen corresponding to different fields of view.

A Study to Investigate the Effect of Valve Mechanisms on Exhaust Residual Gas and Effective Release Energy of a Motorcycle Engine

The purpose of this study was to investigate the effect of valve mechanisms on the exhaust residual gas (ERG) and effective release energy (ERE) of a motorcycle engine. Here, a simulation model and the estimation a new valve mechanism design is presented. An AVL-Boost simulation model and an experiment system were established. The classical spline approximation method was used to design a new cam profile for various valve lifts. The simulation model was used to estimate the effect of the new valve mechanism designs on engine performance. A new camshaft was produced based on the research data. The results show that the engine obtained a maximum engine brake torque of 21.53 Nm at 7000 rpm, which is an increase of 3.2% compared to the engine using the original valve mechanism. In addition, the residual gas was improved, the maximum engine effective release energy was 0.83 kJ, the maximum engine power was 18.1 kW, representing an improvement of 7.2%, and the air mass flow was improved by 4.97%.

Using Division Method to Convert the K-Input MIMO System to SISOs System Combined with Optimal Algorithm Application to Control of a Flexible Link System for the Oscillation (K =1,2)

The flexible link system (FLS) was a highly nonlinear model, multivariable and absolutely unstable dynamic system. In practice, it is common to integrate multiple subsystems into the main system with dynamically turned k-input signals (k =1, 2,…, N) to diversity the functionality of the main system. The flexibility of the division method to convert k-input MIMO system to SISOs system combined with the optimal algorithm creates a powerful tool that can be applied to many different MIMO nonlinear systems with high success rates. The optimal controllers can be created in the future for the flexible system is implemented on an experiment system using Arduino UNO micro-controller KIT. This paper describes division method to convert the k-input MIMO system to SISOs system, after that combined with the optimal algorithm to control for the flexible link system. Specifically, the author will conduct oscillating component analysis of a system with k input pairs (k =1, 2) so that the author can better understand the nature of sub-components as they interact with the system.