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1. VIPER: Spotting Syscall-Guard Variables for Data-Only Attacks

   Ye, Hengkai; Liu, Song; Zhang, Zhechang; Hu, Hong (August 2023, Proceedings of the 32nd USENIX Security Symposium (USENIX 2023))

   As control-flow protection techniques are widely deployed, it is difficult for attackers to modify control data, like function pointers, to hijack program control flow. Instead, data-only attacks corrupt security-critical non-control data (critical data), and can bypass all control-flow protections to revive severe attacks. Previous works have explored various methods to help construct or prevent data-only attacks. However, no solution can automatically detect program-specific critical data. In this paper, we identify an important category of critical data, syscall-guard variables, and propose a set of solutions to automatically detect such variables in a scalable manner. Syscall-guard variables determine to invoke security-related system calls (syscalls), and altering them will allow attackers to request extra privileges from the operating system. We propose branch force, which intentionally flips every conditional branch during the execution and checks whether new security-related syscalls are invoked. If so, we conduct data-flow analysis to estimate the feasibility to flip such branches through common memory errors. We build a tool, VIPER, to implement our ideas. VIPER successfully detects 34 previously unknown syscall-guard variables from 13 programs. We build four new data-only attacks on sqlite and v8, which execute arbitrary command or delete arbitrary file. VIPER completes its analysis within five minutes for most programs, showing its practicality for spotting syscall-guard variables. 

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2. Time-Constrained MPC Approach for Switched Nonlinear Systems With Applications to Biomedical Problems

   https://doi.org/10.1109/LCSYS.2025.3577236  

   Sereno, J E; D’Jorge, A; Ferramosca, Antonio; Hernandez-Vargas, E A; González, A H (January 2025, IEEE Control Systems Letters)

   Switched systems are important for modeling biomedical control problems, where the control action can be considered to be a switching signal to select the active mode (e.g., a drug therapy or intervention). Practical implementations impose constraints not only on the variable magnitudes, but also on each mode’s active and inactive times (AT and IT). To address this, a model predictive control strategy is proposed using an enlarged model with integer state variables to track past AT/IT for each mode. Two biomedical applications were selected to demonstrate the controller’s effectiveness through simulations. The results highlight that our approach is suitable for biomedical applications with intricate temporal requirements. 

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3. Online variable-length source coding for minimum bitrate LQG control

   Cuvelier, T. C.; Tanaka, T.; & Heath, R. W. (April 2023, 2023 IEEE Conference on Decision and Control)

   We propose an adaptive coding approach to achieve linear-quadratic-Gaussian (LQG) control with near- minimum bitrate prefix-free feedback. Our approach combines a recent analysis of a quantizer design for minimum rate LQG control with work on universal lossless source coding for sources on countable alphabets. In the aforementioned quantizer design, it was established that the quantizer outputs are an asymp- totically stationary, ergodic process. To enable LQG control with provably near-minimum bitrate, the quantizer outputs must be encoded into binary codewords efficiently. This is possible given knowledge of the probability distributions of the quantizer outputs, or of their limiting distribution. Obtaining such knowledge is challenging; the distributions do not readily admit closed form descriptions. This motivates the application of universal source coding. Our main theoretical contribution in this work is a proof that (after an invertible transformation), the quantizer outputs are random variables that fall within an exponential or power-law envelope class (depending on the plant dimension). Using ideas from universal coding on envelope classes, we develop a practical, zero-delay version of these algorithms that operates with fixed precision arithmetic. We evaluate the performance of this algorithm numerically, and demonstrate competitive results with respect to fundamental tradeoffs between bitrate and LQG control performance. 

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4. MIP Formulation for Type-III Wind Turbines Considering Control Limits

   https://doi.org/10.1109/NAPS56150.2022.10012164  

   Alqahtani, Mohammed; Miao, Zhixin; Fan, Lingling (October 2022, 2022 North American Power Symposium (NAPS))

   Hitting control limits changes the behavior of the control systems and invalidates commonly adopted assumptions made when calculating the operating point of doubly fed induction generator (DFIG)-based wind turbines (WTs). The current computing methods rely on trials and errors and iterations. This paper proposes an optimization-based algorithm with control limits integrated into the problem formulation. Hitting or not hitting a control limit is modeled as a binary variable. Both rotor-side converter (RSC) current order limits and grid-side converter (GSC) current order limits are modeled in the proposed mixed-integer programming (MIP) formulation. For a WT with given terminal voltage and wind speed, the electrical and mechanical variables of the system can be computed directly from the optimization problem. The proposed formulation has included losses in the back-to-back converters and nonzero reactive power support through GSC. The computing results have been validated with the electromagnetic transient (EMT) simulation results. This formulation can help accurately detect whether control limits are hit for low voltage conditions and facilitate Type-III wind turbine fault ride through analysis. 

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5. Development of Smartphone-Based Human-Robot Interfaces for Individuals with Disabilities

   Lei Wu, Redwan Alqasemi (October 2020, Proceedings of the IEEERSJ International Conference on Intelligent Robots and Systems)

   Persons with disabilities often rely on caregivers or family members to assist in their daily living activities. Robotic assistants can provide an alternative solution if intuitive user interfaces are designed for simple operations. Current humanrobot interfaces are still far from being able to operate in an intuitive way when used for complex activities of daily living (ADL). In this era of smartphones that are packed with sensors, such as accelerometers, gyroscopes and a precise touch screen, robot controls can be interfaced with smartphones to capture the user’s intended operation of the robot assistant. In this paper, we review the current popular human-robot interfaces, and we present three novel human-robot smartphone-based interfaces to operate a robotic arm for assisting persons with disabilities in their ADL tasks. Useful smartphone data, including 3 dimensional orientation and 2 dimensional touchscreen positions, are used as control variables to the robot motion in Cartesian teleoperation. In this paper, we present the three control interfaces, their implementation on a smartphone to control a robotic arm, and a comparison between the results on using the three interfaces for three different ADL tasks. The developed interfaces provide intuitiveness, low cost, and environmental adaptability. 

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