Methodology for Optimal Sizing of Hybrid Power System Usingparticle Swarm Optimization and Dynamic Programming

AbstractA methodology for optimal sizing of hybrid battery-ultracapacitor power system (HPS) is presented. The purpose of the proposed methodology is to locate the optimal voltage levelfor HPS used in a plug-in hybrid electric vehicle (PHEV). A combined optimization framework for a HPS is proposed and the optimization problem is solved in a bi-level manner. The framework contains two nested optimization loops. The outer loop evaluates the selected parameters throughparticle swarm optimization (PSO) algorithm, while the inner loop generates the optimal control strategy and calculates the costs through dynamic programming (DP) algorithm. The Chinese Typical City Bus Drive Cycle (CTCBDC) has beenused to verify and evaluate the performance of the proposed methodology. The optimization result shows that higher voltage degree usually means better performance and the battery tends to provide a constant power for the HPS. It is noted that the constant powercloses to the high efficiency district of the battery and DC/DC convertor. After that the optimal result is further analyzed undervarious optimization goals andbattery charge/discharge current constrains

Sum-Rate Optimization for RIS-Aided Multiuser Communications with Movable Antenna

Reconfigurable intelligent surface (RIS) is known as a promising technology to improve the performance of wireless communication networks, which has been extensively studied. Movable antenna (MA) is a novel technology that fully exploits the antenna position for enhancing the channel capacity. In this paper, we propose a new RIS-aided multiuser communication system with MAs. The sum-rate is maximized by jointly optimizing the beamforming, the reflection coefficient (RC) values of RIS and the positions of MAs. A fractional programming-based iterative algorithm is proposed to solve the formulated non-convex problem, considering three assumptions for the RIS. Numerical results are presented to verify the effectiveness of the proposed algorithm and the superiority of the proposed MA-based system in terms of sum-rate.Comment: 5 page

Reconfigurable fabrication of scattering-free polymer network liquid crystal prism/grating/lens

We report a simple reconfigurable printing method for fabricating submillisecond-response and scattering-free polymer network liquid crystal photonic devices, such as prism, grating, and lens. To suppress light scattering in the visible region, we reduce the domain sizes by controlling polymer concentration, selecting a high viscosity liquid crystal (LC) host, and performing UV curing at a low temperature. To demonstrate the configurability, we printed a LC micro-prism array with similar to 300-mu m feature size and a circular lens with 1.3-mm radius without any pre-patterned templates. This reconfigurable printing technique enables fast design iterations and should have widespread applications for fabricating display and photonic devices

Polarization independent VOA based on dielectrically stretched liquid crystal droplet

A polarization independent variable optical attenuator (VOA) based on a dielectrically stretched liquid crystal (LC) droplet is demonstrated. In the voltage-off state, the proposed VOA has the smallest attenuation. As voltage increases, the LC droplet is stretched by a dielectrophoretic force, which gradually deflects the beam leading to an increased attenuation. Such a VOA can cover the entire C-Band. At lambda = 1550 nm, the following results are obtained: dynamic range similar to 32 dB, insertion loss similar to 0.7 dB, polarization dependent loss similar to 0.3 dB, and response time similar to 20 ms