Understanding Gauge
I consider two usages of the expression “gauge theory.” On one, a gauge theory is a theory with excess structure; on the other, a gauge theory is any theory appropriately related to classical electromagnetism. I make precise one sense in which one formulation of electromagnetism, the paradigmatic gauge theory on both usages, may be understood to have excess structure and then argue that gauge theories on the second usage, including Yang-Mills theory and general relativity, do not generally have excess structure in this sense.
Regarding the ‘Hole Argument’
I argue that the hole argument is based on a misleading use of the mathematical formalism of general relativity. If one is attentive to mathematical practice, I will argue, the hole argument is blocked. 1. Introduction 2. A Warmup Exercise 3. The Hole Argument 4. An Argument from Classical Spacetime Theory 5. The Hole Argument Revisited 1. Introduction 2. A Warmup Exercise 3. The Hole Argument 4. An Argument from Classical Spacetime Theory 5. The Hole Argument Revisited
Application design of a sun-tracking system
As a very good renewable energy, solar energy gets a lot of countries' concerns. How to improve the efficiency of solar panel is now a hot topic and sun tracking is one of the solutions. In this paper, a servo tracking system using dSPACE DS1104 R&D controller board is designed to improve solar collection efficiency. It combines electro-optical tracking and sun trajectory tracking, and can keep solar panels perpendicular to the sun during daylight hours. In order to reduce the amount of computation, a T-S fuzzy system based sun trajectory tracking is proposed. Because of the seamless connection between dSPACE and MATLAB/Simulink, the development cycle time is short. Experimental results show that the system can track the sun precisely and has higher efficiency.