International journal of security and its applications, Nov 30, 2016
Authentication among various devices that form a smart grid is a fundamental issue. Due to the la... more Authentication among various devices that form a smart grid is a fundamental issue. Due to the large-scale, distributed, and heterogeneous nature of a smart grid, authenticating devices based on their credentials such as secret keys is often not practical. Alternatively, certificate-based trust relationships can facilitate interactions in such scenarios. Two pivotal trust relationship models, hierarchical and peer-to-peer, have been well-researched in the literature. However, the devices in a smart grid do not benefit exclusively from a single trust relationship model owing to the heterogeneous nature of its control structure. In this paper, we propose a periodic hierarchical trust relationship model suitable for real-time applications in a smart grid and robust to the single point of failure problem, which is common in hierarchies. The proposed model deploys a two-layer security authentication mechanism among different devices within those domains in which there are control hierarchies using short-term and long-term certificates, the latter of which is verified periodically.
International Journal of Security and Its Applications, 2016
Authentication among various devices that form a smart grid is a fundamental issue. Due to the la... more Authentication among various devices that form a smart grid is a fundamental issue. Due to the large-scale, distributed, and heterogeneous nature of a smart grid, authenticating devices based on their credentials such as secret keys is often not practical. Alternatively, certificate-based trust relationships can facilitate interactions in such scenarios. Two pivotal trust relationship models, hierarchical and peer-to-peer, have been well-researched in the literature. However, the devices in a smart grid do not benefit exclusively from a single trust relationship model owing to the heterogeneous nature of its control structure. In this paper, we propose a periodic hierarchical trust relationship model suitable for real-time applications in a smart grid and robust to the single point of failure problem, which is common in hierarchies. The proposed model deploys a two-layer security authentication mechanism among different devices within those domains in which there are control hierarchies using short-term and long-term certificates, the latter of which is verified periodically.
This paper introduces the reader to the concepts of fuzzy sets and fuzzy logic and to their capab... more This paper introduces the reader to the concepts of fuzzy sets and fuzzy logic and to their capabilities in the area of control systems. To understand the capabilities of fuzzy logic in real-time controller design, a controller for an environmentally conscious refrigeration system was designed and implemented. Initial results show that a fuzzy logic controller is easy to implement, does not need an exact system model, does not need precise and expensive hardware, and deals with human concepts in a fairly natural and obvious way. This would be, hopefully, a potential avenue for future production of intelligent manufactured products.
: An optimal tension regulator system is designed for a steel strip winding process. A simplified... more : An optimal tension regulator system is designed for a steel strip winding process. A simplified dynamic model of the winding process contains a parametric nonlinearity due to variations of the coil radius. A parameter imbedding technique is applied to derive the optimum feedback control for a range of parameter values. Simulation results are given for an implementation of the regulator system designed using the numerical values from a real plant. (Author)
: The dynamic model of a continuous cold reduction mill is developed. The model makes use of a fo... more : The dynamic model of a continuous cold reduction mill is developed. The model makes use of a force-torque equation expansion technique and presents the generalized (7N+8)th order state equation for an N-stand rolling mill. The equations of interstand tensions are found to be highly nonlinear with the arguments delayed due to the transition of strip between the stands. The model developed can be used in the design of a controller for the entire rolling process. (Author)
Soft Computing - A Fusion of Foundations, Methodologies and Applications, 1997
One of the biggest challenges of any control paradigm is being able to handle large complex syste... more One of the biggest challenges of any control paradigm is being able to handle large complex systems. A system may be called large-scale or complex, here, if its dimension (order) is so high and its model (if available) is nonlinear, interconnected with uncertain information flow such that classical techniques of control theory cannot easily handle the system. From a control theoretical point of view, fuzzy logic has been intermixed with all the important aspects of systems theory-modeling, identification, analysis, stability, synthesis, filtering, and estimation. However, the application of fuzzy control to large-scale complex systems is not a trivial task by any means. For such systems the size of the rule base in a typical fuzzy control architecture will be nearly infinite. In this paper an attempt is made to break some new ground on the applications of fuzzy control to complex systems. A new rule base reduction approach is suggested to manage large inference engines. Notions of rule hierarchy and sensor data fusion are introduced and combined to achieve system's goals. The technique has been implemented on an SGS Thomson W.A.R.P. chip for an inverted pendulum with wine-balancing application.
2019 IEEE 10th Annual Ubiquitous Computing, Electronics & Mobile Communication Conference (UEMCON)
Object detection has been a very hot research topic since the advent of artificial intelligence a... more Object detection has been a very hot research topic since the advent of artificial intelligence and machine learning. Its importance is very high specifically in advancing autonomous vehicles technology. Many object detection methods have been developed based on different types of data including image, radar, and lidar. Some recent works use point clouds for 3D object detection. One of the recently presented efficient methods is PointPillars, an encoder which learns from data in a point cloud and organizes a representation in vertical columns (pillars) for 3D object detection. in this work, we use PointPillars with lidar data of some urban scenes provided in nuScenes dataset to predict 3D boxes for three different classes of objects (car, pedestrian, bus). We also use nuScenes detection score (NDS) which is a consolidated metric for detection task, to measure and compare different scenarios. Results show that by increasing the number of lidar sweeps, the performance of the 3D object detector improves significantly. We try to increase the performance of the encoder by developing a method to combine different types of input data (lidar, radar, image) based on a weighting system and use it as the input of the encoder.
Proceedings of the 1998 IEEE International Conference on Control Applications (Cat. No.98CH36104)
In this paper we design a state-feedback controller for the nonlinear benchmark problem. Our appr... more In this paper we design a state-feedback controller for the nonlinear benchmark problem. Our approach relies on the use of Takagi-Sugeno fuzzy models to approximate the nonlinear system. Once €he fuzzy model is obtained, we develop a guaranteed-cost framework to design the controller using Linear Matrix Inequality methods and recently obtained relaxed stability conditions. We show that our proposed controller will not only stabilize the system, but also has satisfactory disturbance attenuation properties.
We consider a widely studied consensus algorithm for processing sensor data of multi-missile syst... more We consider a widely studied consensus algorithm for processing sensor data of multi-missile systems. A new algorithm to reach a consensus given time delay constraints is proposed. The algorithm performance was evaluated in a scenario where four missiles are measuring and estimating the location of a ground maneuvering target. Each missile computes its state prediction and shares it with its neighbors only. However, the shared information arrives at each agent with time delays. The entire group of missiles must reach a consensus on target’s state. Different scenarios were also simulated to examine the effectiveness and performance in terms of overall estimation error, disagreement between delayed and non-delayed agents, and time to reach a consensus for each parameter. The effectiveness of the number of missiles performing observation, the delay value, and sensor uncertainty were also simulated to determine the relation between these parameters and the overall performance of the alg...
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