On the Verification of Deep Reinforcement Learning Solution for Intelligent Operation of Distribution Grids

Capabilities of deep reinforcement learning (DRL) in obtaining fast decision policies in high dimensional and stochastic environments have led to its extensive use in operational research, including the operation of distribution grids with high penetration of distributed energy resources (DER). However, the feasibility and robustness of DRL solutions are not guaranteed for the system operator, and hence, those solutions may be of limited practical value. This paper proposes an analytical method to find feasibility ellipsoids that represent the range of multi-dimensional system states in which the DRL solution is guaranteed to be feasible. Empirical studies and stochastic sampling determine the ratio of the discovered to the actual feasible space as a function of the sample size. In addition, the performance of logarithmic, linear, and exponential penalization of infeasibility during the DRL training are studied and compared in order to reduce the number of infeasible solutions

Hierarchical Flexibility Offering Strategy for Integrated Hybrid Resources in Real-time Energy Markets

This paper proposes a hierarchical model for determining the energy flexibility offering strategy of integrated hybrid resources (IHRs) in power distribution systems to participate in real-time energy markets. The proposed model utilizes the scalability, fast response time, and uncertainty observation of deep reinforcement learning (DRL) to overcome the scalability issue of operating numerous flexible resources and deliverability of energy flexibility to the real-time markets in the presence of the network constraints. To that end, the power distribution system is divided into multiple IHRs, where different types of flexible loads, energy storage systems, and solar plants with controllable inverters are operated through local IHR controllers, trained by deep deterministic policy gradient (DDPG) algorithm. Active power request and reactive power capacity of IHRs are then transmitted to a central flexibility controller, where a quadratic optimization model ensures the deliverability of the energy flexibility to the real-time energy market by satisfying the distribution network constraints. The proposed model is implemented on the 123-bus test power distribution system, demonstrating the capability of DRL-based hierarchical model for scalable operation of IHRs in order to offer deliverable energy flexibility to the real-time energy market

Applying mean shift and motion detection approaches to hand tracking in sign language

Hand gesture recognition is very important to communicate in sign language. In this paper, an effective object tracking and hand gesture recognition method is proposed. This method is combination of two well-known approaches, the mean shift and the motion detection algorithm. The mean shift algorithm can track objects based on the color, then when hand passes the face occlusion happens. Several solutions such as the particle filter, kalman filter and dynamic programming tracking have been used, but they are complicated, time consuming and so expensive. The proposed method is so easy, fast, efficient and low cost. In the first step, the motion detection algorithm subtracts the previous frame from the current frame to obtain the changes between two images and white pixels (motion level) are detected by using the threshold level. Then the mean shift algorithm is applied for tracking the hand motion. Simulation results show this method is faster than two times to compared with the old common algorithm

Relationship between mothers\' awareness of eruption time of first permanent molar and its caries in 7-9-year-old children

Introduction: Since the first permanent molar (FPM) as a first permanent tooth erupts between 6-7 years old and has a long period of eruption, it is the most caries prone tooth. One of the problems is inadequate knowledge of parents about the eruption time of the FPM; because these teeth erupt behind the deciduous teeth without a primary successor. In the present study, mothers' knowledge about its eruption time and its effect on health of these teeth was evaluated. Materials& Methods: This cross-sectional study was conducted on 406 schoolchildren (7-9 years old) and their mothers using multi-stage sampling in Babol in 2017. Mothers completed the check list according to the study objectives. Clinical status of FPM was measured using DMFT (Decayed, Missed, Filled Teeth) index. Finally, data were analyzed with SPSS 18 using t-test and chi-square. Significance level was considered as p<0.05. Results: Mothers’ awareness about the eruption time of FPM (p<0.001) was associated with higher ratio of children with sound FPM. Mothers’ education level was the most significant contributing factor to mothers' knowledge about FPM eruption time. Conclusion: Mothers’ education and their knowledge about the FPMs eruption time were the major predictors of FPM caries status

Compound Hertzian Chain Model for Copper-Carbon Nanocomposites' Absorption Spectrum

The infrared range optical absorption mechanism of Carbon-Copper composite thin layer coated on the Diamond-Like Carbon (DLC) buffer layer has been investigated. By consideration of weak interactions between copper nanoparticles in their network, optical absorption is modeled using their coherent dipole behavior induced by the electromagnetic radiation. The copper nanoparticles in the bulk of carbon are assumed as a chain of plasmonic dipoles, which have coupling resonance. Considering nearest neighbor interactions for this metallic nanoparticles, surface plasmon resonance frequency ({\omega}\neg0) and coupled plasmon resonance frequency ({\omega}\neg1) have been computed. The damping rate versus wavelength is derived which leads to the derivation of the optical absorption spectrum in the term of {\omega}\neg0 and {\omega}\neg1. The dependency of the absorption peaks to the particle-size and the particle mean spacing is also investigated. The absorption spectrum is measured for different Cu-C thin films with various Cu particle size and spacing. The experimental results of absorption are compared with the obtained analytical ones.Comment: 7 pages, 4 figure