Multiple security domain nondeducibility in cyber-physical systems

Cyber-physical Systems (CPS) present special problems for security. This dissertation examines the cyber security problem, the physical security problem, the security problems presented when cyber systems and physical systems are intertwined, and problems presented by the fact that CPS leak information simply by being observed. The issues presented by applying traditional cyber security to CPS are explored and some of the shortcomings of these models are noted. Specific models of a drive-by-wire\u27\u27 automobile connected to a road side assistance network, a Stuxnet type\u27\u27 attack, the smart grid, and others are presented in detail. The lack of good tools for CPS security is addressed in part by the introduction of a new model, Multiple Security Domains Nondeducibility over an Event System, or MSDND(ES). The drive-by-wire automobile is studied to show how MSDND(ES) is applied to a system that traditional security models do not describe well. The issue of human trust in inherently vulnerable CPS with embedded cyber monitors, is also explored. A Stuxnet type attack on a CPS is examined using both MSDND(ES) and Belief, Information acquisition, and Trust (BIT) logic to provide a clear and precise method to discuss issues of trust and belief in monitors and electronic reports. To show these techniques, the electrical smart grid as envisioned by the Future Renewable Electric Energy Delivery and Management Systems Center (FREEDM) project is also modeled. Areas that may lead to the development of additional tools are presented as possible future work to address the fact: CPS are different and require different models and tools to understand. --Abstract, page iii

Investigation on maneuverability improvement of a four-wheel drive and rear-wheel steering system : numerical simulation analysis

X-by-wire technology is an advancement in the automotive industry and is recognized by many countries in recent years. It includes drive-by-wire (DBW) and steer-by-wire (SBW). DBW is available in two-wheel drive (2WD) and four-wheel drive (4WD) forms. 4WD has two forms: centralized motor drive and distributed motor drive. A centralized motor drive is to use the motor to replace the engine to provide power for the vehicle. The distributed motor drive is mainly based on the in-wheel motor, and the wheel is driven by the in-wheel motor to provide power for the vehicle. SBW has two forms: two-wheel steering (2WS) and four-wheel steering (4WS). It not only dramatically reduces the operating burden of the driver but also solves the problem that ordinary vehicles cannot perform 4WS. Usually, the lower maneuverability is easy to show on 2WS vehicles during vehicle turning. No matter when driving a vehicle on a narrow city road or parking, it is required to turn the steering wheel several times when the vehicle needs to steer. Moreover, the vehicle can be prone to understeer (US) or oversteer (OS) phenomena that occur when steering. The main purpose of this research is to simulate the steering performance of the vehicle by constructing a model of modern conventional vehicles and to solve the problems that may occur during vehicle cornering by applying an active 4WS control system to control the yaw rate. In this research, experiments of 2WS cornering at several constant speeds and steer angles were conducted using an actual experimental vehicle. A simulation model of the test car was constructed in MATLAB Simulink using nonlinear vehicle dynamics equations with the specification of the vehicle as the parameters. A PID control system was used in this simulation to control the rear-wheel steering angle in order to achieve 4WS. By comparing the simulation and the experimental result, it can be concluded that the nonlinear vehicle dynamics equation can be used to do the simulation of the vehicle motion. After verifying the vehicle dynamics equation, in order to verify whether the time of rotating the steering wheel will affect the motion of the vehicle, this study simulated two different times to complete the rotation of the wheel which is 2 seconds and 25 seconds with the front steering angle is 10 degrees. The results show that no matter whether the time of steering wheel rotation is fast or slow, it does not affect the speed of the vehicle's US and OS phenomenon. By simulating the cornering situation of the vehicle speeds from 10km/h to 80 km/h in the 10km/h increment. It is concluded that the vehicle will occur US phenomenon when the vehicle turning speed is lower around 20km/h; when the vehicle corners with a speed higher than 50km/h, the vehicle will have an OS phenomenon happen. After applying the 4WS system, the OS and US problems are solved efficiently. Although the vehicle is turning at a speed of 80km/h, steady-state cornering (SSC) can still be achieved. After applying the PID control system, most of the cornering can be controlled. except when the wheels rotate to 10° in only two seconds and the vehicle speed is greater than 60km/h which is the vehicle is out of control in a very short time, the PID control system cannot make the rear wheels have an appropriate steering angle to make the vehicle have an SSC. In short, this study solved almost all US and OS phenomena that can occur in 2WS vehicles by applying the 4WS system

Models of leader elections and their applications

New research about cyber-physical systems is rapidly changing the way we think about critical infrastructures such as the power grid. Changing requirements for the generation, storage, and availability of power are all driving the development of the smart-grid. Many smart-grid projects disperse power generation across a wide area and control devices with a distributed system. However, in a distributed system, the state of processes is hard to determine due to isolation of memory. By using information flow security models, we reason about a process\u27s beliefs of the system state in a distributed system. Information flow analysis aided in the creation of Markov models for the expected behavior of a cyber controller in a smart-grid system using a communication network with omission faults. The models were used as part of an analysis of the distributed system behavior when there are communication faults. With insight gained from these models, existing congestion management techniques were extended to create a feedback mechanism, allowing the cyber-physical system to better react to issues in the communication network --Abstract, page iii

Modeling and Reasoning about the Security of Drive-By-Wire Automobile Systems

An increasing number of modern automobiles are essentially drive-by-wire systems, highly computerized, and connected wirelessly to services such as OnStar or Toyota Safety Connect. While these features enhance automobile safety and reliability, the security impact is a growing concern. This paper examines the security of drive-by-wire automobile systems. Generic models of access control and information flow are defined, with specific instances of the 2010 Toyota Prius used where appropriate. The automobile systems are examined from the viewpoint of the driver with special emphasis on the driver\u27s ability to determine who, or what, is actually in control of the automobile in critical situations