Qinglong Wang

Smart Charging for Electric Vehicles: A Survey From the Algorithmic Perspective

Smart interactions among the smart grid, aggregators, and EVs can bring various benefits to all parties involved, e.g., improved reliability and safety for the smart gird, increased profits for the aggregators, as well as enhanced self benefit for EV customers. This survey focuses on viewing this smart interactions from an algorithmic perspective. In particular, important dominating factors for coordinated charging from three different perspectives are studied, in terms of smart grid oriented, aggregator-oriented, and customer-oriented smart charging. Firstly, for smart grid oriented EV charging, we summarize various formulations proposed for load flattening, frequency regulation, and voltage regulation, then explore the nature and substantial similarity among them. Secondly, for aggregator-oriented EV charging, we categorize the algorithmic approaches proposed by research works sharing this perspective as direct and indirect coordinated control, and investigate these approaches in detail. Thirdly, for customer-oriented EV charging, based on a commonly shared objective of reducing charging cost, we generalize different formulations proposed by studied research works. Moreover, various uncertainty issues, e.g., EV fleet uncertainty, electricity price uncertainty, regulation demand uncertainty, etc., have been discussed according to the three perspectives classified. At last, we discuss challenging issues that are commonly confronted during modeling the smart interactions, and outline some future research topics in this exciting area.

Adversary Resistant Deep Neural Networks with an Application to Malware Detection

Outside the highly publicized victories in the game of Go, there have been numerous successful applications of deep learning in the fields of information retrieval, computer vision, and speech recognition. In cybersecurity, an increasing number of companies have begun exploring the use of deep learning (DL) in a variety of security tasks with malware detection among the more popular. These companies claim that deep neural networks (DNNs) could help turn the tide in the war against malware infection. However, DNNs are vulnerable to adversarial samples, a shortcoming that plagues most, if not all, statistical and machine learning models. Recent research has demonstrated that those with malicious intent can easily circumvent deep learning-powered malware detection by exploiting this weakness. To address this problem, previous work developed defense mechanisms that are based on augmenting training data or enhancing model complexity. However, after analyzing DNN susceptibility to adversarial samples, we discover that the current defense mechanisms are limited and, more importantly, cannot provide theoretical guarantees of robustness against adversarial sampled-based attacks. As such, we propose a new adversary resistant technique that obstructs attackers from constructing impactful adversarial samples by randomly nullifying features within data vectors. Our proposed technique is evaluated on a real world dataset with 14,679 malware variants and 17,399 benign programs. We theoretically validate the robustness of our technique, and empirically show that our technique significantly boosts DNN robustness to adversarial samples while maintaining high accuracy in classification. To demonstrate the general applicability of our proposed method, we also conduct experiments using the MNIST and CIFAR-10 datasets, widely used in image recognition research.

Smart rate control and demand balancing for electric vehicle charging

The anticipated high electric vehicle (EV) penetration motivates many research efforts to alleviate the potential associated grid impact. However, few works discuss the crucial issue: quality of service (QoS) degradation caused by competing for charging resources. This issue arises due to the limitation on power supply and charging space that charging stations can usually provide. Our work studies this issue and proposes an operational scheme that optimizes QoS for EV users while satisfying the stability of the power grid. The scheme consists of two levels. The lower level deals with charging rate control, for which we propose an efficient algorithm with provable QoS-optimal allocation of power supply to EVs. The upper level handles charging demand balancing, for which we design two approximation algorithms that schedule EVs to multiple charging stations. One algorithm is a 3-approximation with polynomial complexity; while the other is a (2+ε)-approximation using a fully polynomial time approximation scheme. Through extensive simulations based on realistic data traces and simulations tools, we demonstrate the efficiency and efficacy of our operational scheme and further provide interesting findings from in-depth analysis of the experimental results.

An Empirical Evaluation of Rule Extraction from Recurrent Neural Networks

Rule extraction from black box models is critical in domains that require model validation before implementation, as can be the case in credit scoring and medical diagnosis. Though already a challenging problem in statistical learning in general, the difficulty is even greater when highly nonlinear, recursive models, such as recurrent neural networks (RNNs), are fit to data. Here, we study the extraction of rules from second-order RNNs trained to recognize the Tomita grammars. We show that production rules can be stably extracted from trained RNNs and that in certain cases, the rules outperform the trained RNNs.