pwc-archive/papers-with-abstracts huggingface dataset:
ALERT: A Comprehensive Benchmark for Assessing Large Language Models' Safety through Red Teaming
Authors: Simone Tedeschi, Felix Friedrich, Patrick Schramowski, Kristian Kersting, Roberto Navigli, Huu Nguyen, Bo Li
Date: 2024-04-06 00:00:00
Tasks: Adversarial Robustness, Dialogue Safety Prediction, Red Teaming

When building Large Language Models (LLMs), it is paramount to bear safety in mind and protect them with guardrails. Indeed, LLMs should never generate content promoting or normalizing harmful, illegal, or unethical behavior that may contribute to harm to individuals or society. This principle applies to both normal and adversarial use. In response, we introduce ALERT, a large-scale benchmark to assess safety based on a novel fine-grained risk taxonomy. It is designed to evaluate the safety of LLMs through red teaming methodologies and consists of more than 45k instructions categorized using our novel taxonomy. By subjecting LLMs to adversarial testing scenarios, ALERT aims to identify vulnerabilities, inform improvements, and enhance the overall safety of the language models. Furthermore, the fine-grained taxonomy enables researchers to perform an in-depth evaluation that also helps one to assess the alignment with various policies. In our experiments, we extensively evaluate 10 popular open- and closed-source LLMs and demonstrate that many of them still struggle to attain reasonable levels of safety.
Sentiment analysis and random forest to classify LLM versus human source applied to Scientific Texts
Authors: Javier J. Sanchez-Medina
Date: 2024-04-05 00:00:00
Tasks: Feature Engineering, Sentiment Analysis

After the launch of ChatGPT v.4 there has been a global vivid discussion on the ability of this artificial intelligence powered platform and some other similar ones for the automatic production of all kinds of texts, including scientific and technical texts. This has triggered a reflection in many institutions on whether education and academic procedures should be adapted to the fact that in future many texts we read will not be written by humans (students, scholars, etc.), at least, not entirely. In this work it is proposed a new methodology to classify texts coming from an automatic text production engine or a human, based on Sentiment Analysis as a source for feature engineering independent variables and then train with them a Random Forest classification algorithm. Using four different sentiment lexicons, a number of new features where produced, and then fed to a machine learning random forest methodology, to train such a model. Results seem very convincing that this may be a promising research line to detect fraud, in such environments where human are supposed to be the source of texts.
AAM-VDT: Vehicle Digital Twin for Tele-Operations in Advanced Air Mobility
Authors: Tuan Anh Nguyen, Taeho Kwag, Vinh Pham, Viet Nghia Nguyen, Jeongseok Hyun, Minseok Jang, Jae-Woo Lee
Date: 2024-04-15 00:00:00

This study advanced tele-operations in Advanced Air Mobility (AAM) through the creation of a Vehicle Digital Twin (VDT) system for eVTOL aircraft, tailored to enhance remote control safety and efficiency, especially for Beyond Visual Line of Sight (BVLOS) operations. By synergizing digital twin technology with immersive Virtual Reality (VR) interfaces, we notably elevate situational awareness and control precision for remote operators. Our VDT framework integrates immersive tele-operation with a high-fidelity aerodynamic database, essential for authentically simulating flight dynamics and control tactics. At the heart of our methodology lies an eVTOL's high-fidelity digital replica, placed within a simulated reality that accurately reflects physical laws, enabling operators to manage the aircraft via a master-slave dynamic, substantially outperforming traditional 2D interfaces. The architecture of the designed system ensures seamless interaction between the operator, the digital twin, and the actual aircraft, facilitating exact, instantaneous feedback. Experimental assessments, involving propulsion data gathering, simulation database fidelity verification, and tele-operation testing, verify the system's capability in precise control command transmission and maintaining the digital-physical eVTOL synchronization. Our findings underscore the VDT system's potential in augmenting AAM efficiency and safety, paving the way for broader digital twin application in autonomous aerial vehicles.
Do Large Language Models Learn Human-Like Strategic Preferences?
Authors: Jesse Roberts, Kyle Moore, Doug Fisher
Date: 2024-04-11 00:00:00

In this paper, we evaluate whether LLMs learn to make human-like preference judgements in strategic scenarios as compared with known empirical results. Solar and Mistral are shown to exhibit stable value-based preference consistent with humans and exhibit human-like preference for cooperation in the prisoner's dilemma (including stake-size effect) and traveler's dilemma (including penalty-size effect). We establish a relationship between model size, value-based preference, and superficiality. Finally, results here show that models tending to be less brittle have relied on sliding window attention suggesting a potential link. Additionally, we contribute a novel method for constructing preference relations from arbitrary LLMs and support for a hypothesis regarding human behavior in the traveler's dilemma.
Is English the New Programming Language? How About Pseudo-code Engineering?
Authors: Gian Alexandre Michaelsen, Renato P. dos Santos
Date: 2024-04-08 00:00:00
Tasks: Language Modelling, Prompt Engineering

Background: The integration of artificial intelligence (AI) into daily life, particularly through chatbots utilizing natural language processing (NLP), presents both revolutionary potential and unique challenges. This intended to investigate how different input forms impact ChatGPT, a leading language model by OpenAI, performance in understanding and executing complex, multi-intention tasks. Design: Employing a case study methodology supplemented by discourse analysis, the research analyzes ChatGPT's responses to inputs varying from natural language to pseudo-code engineering. The study specifically examines the model's proficiency across four categories: understanding of intentions, interpretability, completeness, and creativity. Setting and Participants: As a theoretical exploration of AI interaction, this study focuses on the analysis of structured and unstructured inputs processed by ChatGPT, without direct human participants. Data collection and analysis: The research utilizes synthetic case scenarios, including the organization of a "weekly meal plan" and a "shopping list," to assess ChatGPT's response to prompts in both natural language and pseudo-code engineering. The analysis is grounded in the identification of patterns, contradictions, and unique response elements across different input formats. Results: Findings reveal that pseudo-code engineering inputs significantly enhance the clarity and determinism of ChatGPT's responses, reducing ambiguity inherent in natural language. Enhanced natural language, structured through prompt engineering techniques, similarly improves the model's interpretability and creativity. Conclusions: The study underscores the potential of pseudo-code engineering in refining human-AI interaction and achieving more deterministic, concise, and direct outcomes, advocating for its broader application across disciplines requiring precise AI responses.
Effects of Different Prompts on the Quality of GPT-4 Responses to Dementia Care Questions
Authors: Zhuochun Li, Bo Xie, Robin Hilsabeck, Alyssa Aguirre, Ning Zou, Zhimeng Luo, Daqing He
Date: 2024-04-05 00:00:00

Evidence suggests that different prompts lead large language models (LLMs) to generate responses with varying quality. Yet, little is known about prompts' effects on response quality in healthcare domains. In this exploratory study, we address this gap, focusing on a specific healthcare domain: dementia caregiving. We first developed an innovative prompt template with three components: (1) system prompts (SPs) featuring 4 different roles; (2) an initialization prompt; and (3) task prompts (TPs) specifying different levels of details, totaling 12 prompt combinations. Next, we selected 3 social media posts containing complicated, real-world questions about dementia caregivers' challenges in 3 areas: memory loss and confusion, aggression, and driving. We then entered these posts into GPT-4, with our 12 prompts, to generate 12 responses per post, totaling 36 responses. We compared the word count of the 36 responses to explore potential differences in response length. Two experienced dementia care clinicians on our team assessed the response quality using a rating scale with 5 quality indicators: factual, interpretation, application, synthesis, and comprehensiveness (scoring range: 0-5; higher scores indicate higher quality).
A competitive game optimization algorithm for Unmanned Aerial Vehicle path planning
Authors: Tai-shan Lou, Guang-sheng Guan, Zhe-peng Yue, Yu Wang, Ren-long Qi, Shi-hao Tong
Date: 2024-04-15 00:00:00

To solve the Unmanned Aerial Vehicle (UAV) path planning problem, a meta-heuristic optimization algorithm called competitive game optimizer (CGO) is proposed. In the CGO model, three phases of exploration and exploitation, and candidate replacement, are established, corresponding to the player's search for supplies and combat, and the movement toward a safe zone. In the algorithm exploration phase, Levy flight is introduced to improve the global convergence of the algorithm. The encounter probability which adaptively changes with the number of iterations is also introduced in the CGO. The balance between exploration and exploitation of solution space of optimization problem is realized, and each step is described and modeled mathematically. The performance of the CGO was evaluated on a set of 41 test functions taken from CEC2017 and CEC2022. It was then compared with eight widely recognized meta-heuristic optimization algorithms. The simulation results demonstrate that the proposed algorithm successfully achieves a balanced trade-off between exploration and exploitation, showcasing remarkable advantages when compared to seven classical algorithms. In addition, in order to further verify the effectiveness of the CGO, the CGO is applied to 8 practical engineering design problems and UAV path planning, and the results show that the CGO has strong performance in dealing with these practical optimization problems, and has a good application prospect.
Moving horizon estimation for nonlinear systems with time-varying parameters
Authors: Julian D. Schiller, Matthias A. Müller
Date: 2024-04-15 00:00:00
Tasks: valid

We propose a moving horizon estimation scheme for estimating the states and time-varying parameters of nonlinear systems. We consider the case where observability of the parameters depends on the excitation of the system and may be absent during operation, with the parameter dynamics fulfilling a weak incremental bounded-energy bounded-state property to ensure boundedness of the estimation error (with respect to the disturbance energy). The proposed estimation scheme involves a standard quadratic cost function with an adaptive regularization term depending on the current parameter observability. We develop robustness guarantees for the overall estimation error that are valid for all times, and that improve the more often the parameters are detected to be observable during operation. The theoretical results are illustrated by a simulation example.
MPC Based Linear Equivalence with Control Barrier Functions for VTOL-UAVs
Authors: Ali Mohamed Ali, Hashim A. Hashim, Chao Shen
Date: 2024-04-14 00:00:00
Tasks: Model Predictive Control

In this work, we propose a cascaded scheme of linear Model prediction Control (MPC) based on Control Barrier Functions (CBF) with Dynamic Feedback Linearization (DFL) for Vertical Take-off and Landing (VTOL) Unmanned Aerial Vehicles (UAVs). CBF is a tool that allows enforcement of forward invariance of a set using Lyapunov-like functions to ensure safety. The First control synthesis that employed CBF was based on Quadratic Program (QP) that modifies the existing controller to satisfy the safety requirements. However, the CBF-QP-based controllers leading to longer detours and undesirable transient performance. Recent contributions utilize the framework of MPC benefiting from the prediction capabilities and constraints imposed on the state and control inputs. Due to the intrinsic nonlinearities of the dynamics of robotics systems, all the existing MPC-CBF solutions rely on nonlinear MPC formulations or operate on less accurate linear models. In contrast, our novel solution unlocks the benefits of linear MPC-CBF while considering the full underactuated dynamics without any linear approximations. The cascaded scheme converts the problem of safe VTOL-UAV navigation to a Quadratic Constraint Quadratic Programming (QCQP) problem solved efficiently by off-the-shelf solvers. The closed-loop stability and recursive feasibility is proved along with numerical simulations showing the effective and robust solutions. Keywords: Unmanned Aerial Vehicles, Vertical Take-off and Landing, Model Predictive Control, MPC, Nonlinearity, Dynamic Feedback Linearization, Optimal Control.
Numerical Discretization Methods for the Extended Linear Quadratic Control Problem
Authors: Zhanhao Zhang, Jan Lorenz Svensen, Morten Wahlgreen Kaysfeld, Anders Hilmar Damm Christensen, Steen Hørsholt, John Bagterp Jørgensen
Date: 2024-04-14 00:00:00

In this study, we introduce numerical methods for discretizing continuous-time linear-quadratic optimal control problems (LQ-OCPs). The discretization of continuous-time LQ-OCPs is formulated into differential equation systems, and we can obtain the discrete equivalent by solving these systems. We present the ordinary differential equation (ODE), matrix exponential, and a novel step-doubling method for the discretization of LQ-OCPs. Utilizing Euler-Maruyama discretization with a fine step, we reformulate the costs of continuous-time stochastic LQ-OCPs into a quadratic form, and show that the stochastic cost follows the $\chi^2$ distribution. In the numerical experiment, we test and compare the proposed numerical methods. The results ensure that the discrete-time LQ-OCP derived using the proposed numerical methods is equivalent to the original problem.
A Model Predictive Control Scheme for Flight Scheduling and Energy Management of Electric Aviation Networks
Authors: Finn Vehlhaber, Mauro Salazar
Date: 2024-04-14 00:00:00
Tasks: energy management, Management, Model Predictive Control, Scheduling

This paper presents a Model Predictive Control (MPC) scheme for flight scheduling and energy management of electric aviation networks, where electric aircraft transport passengers between electrified airports equipped with sustainable energy sources and battery storage, with the goal of minimizing grid dependency. Specifically, we first model the aircraft flight and charge scheduling problem jointly with the airport energy management problem, explicitly accounting for local weather forecasts. Second, we frame the minimum-grid-energy operational problem as a mixed-integer linear program and solve it in a receding horizon fashion, where the route assignment and charging decisions of each aircraft can be dynamically reassigned to mitigate disruptions. We showcase the proposed MPC scheme on real-world data taken from conventional flights and weather conditions in the Dutch Leeward Antilles. Our results show that MPC can effectively guarantee operation of the network by efficiently re-assigning flights and rescheduling aircraft charging, whilst maximizing the efficiency of the on-site energy systems.
On Joint Convergence of Traffic State and Weight Vector in Learning-Based Dynamic Routing with Value Function Approximation
Authors: Yidan Wu, Jianan Zhang, Li Jin
Date: 2024-04-14 00:00:00

Learning-based approaches are increasingly popular for traffic control problems. However, these approaches are applied typically as black boxes with limited theoretical guarantees and interpretability. In this paper, we consider the theory of dynamic routing over parallel servers, a representative traffic control task, using semi-gradient on-policy control algorithm, a representative reinforcement learning method. We consider a linear value function approximation on an infinite state space; a Lyapunov function is also derived from the approximator. In particular, the structure of the approximator naturally makes possible idling policies, which is an interesting and useful advantage over existing dynamic routing schemes. We show that the convergence of the approximation weights is coupled with the convergence of the traffic state. We show that if the system is stabilizable, then (i) the weight vector converges to a bounded region, and (ii) the traffic state is bounded in the mean. We also empirically show that the proposed algorithm is computationally efficient with an insignificant optimality gap.
Data-driven AC Optimal Power Flow with Physics-informed Learning and Calibrations
Authors: Junfei Wang, Pirathayini Srikantha
Date: 2024-04-14 00:00:00
Tasks: Physics-informed machine learning

The modern power grid is witnessing a shift in operations from traditional control methods to more advanced operational mechanisms. Due to the nonconvex nature of the Alternating Current Optimal Power Flow (ACOPF) problem and the need for operations with better granularity in the modern smart grid, system operators require a more efficient and reliable ACOPF solver. While data-driven ACOPF methods excel in directly inferring the optimal solution based on power grid demand, achieving both feasibility and optimality remains a challenge due to the NP-hardness of the problem. In this paper, we propose a physics-informed machine learning model and a feasibility calibration algorithm to produce solutions for the ACOPF problem. Notably, the machine learning model produces solutions with a 0.5\% and 1.4\% optimality gap for IEEE bus 14 and 118 grids, respectively. The feasibility correction algorithm converges for all test scenarios on bus 14 and achieves a 92.2% convergence rate on bus 118.
Statistical Analysis of Block Coordinate Descent Algorithms for Linear Continuous-time System Identification
Authors: Rodrigo A. González, Koen Classens, Cristian R. Rojas, James S. Welsh, Tom Oomen
Date: 2024-04-13 00:00:00

Block coordinate descent is an optimization technique that is used for estimating multi-input single-output (MISO) continuous-time models, as well as single-input single output (SISO) models in additive form. Despite its widespread use in various optimization contexts, the statistical properties of block coordinate descent in continuous-time system identification have not been covered in the literature. The aim of this paper is to formally analyze the bias properties of the block coordinate descent approach for the identification of MISO and additive SISO systems. We characterize the asymptotic bias at each iteration, and provide sufficient conditions for the consistency of the estimator for each identification setting. The theoretical results are supported by simulation examples.
Intention-Aware Control Based on Belief-Space Specifications and Stochastic Expansion
Authors: Zengjie Zhang, Zhiyong Sun, Sofie Haesaert
Date: 2024-04-13 00:00:00
Tasks: Autonomous Driving, Model Predictive Control

This paper develops a correct-by-design controller for an autonomous vehicle interacting with opponent vehicles with unknown intentions. We define an intention-aware control problem incorporating epistemic uncertainties of the opponent vehicles and model their intentions as discrete-valued random variables. Then, we focus on a control objective specified as belief-space temporal logic specifications. From this stochastic control problem, we derive a sound deterministic control problem using stochastic expansion and solve it using shrinking-horizon model predictive control. The solved intention-aware controller allows a vehicle to adjust its behaviors according to its opponents' intentions. It ensures provable safety by restricting the probabilistic risk under a desired level. We show with experimental studies that the proposed method ensures strict limitation of risk probabilities, validating its efficacy in autonomous driving cases. This work provides a novel solution for the risk-aware control of interactive vehicles with formal safety guarantees.
A Framework for Safe Probabilistic Invariance Verification of Stochastic Dynamical Systems
Authors: Taoran Wu, Yiqing Yu, Bican Xia, Ji Wang, Bai Xue
Date: 2024-04-13 00:00:00

Ensuring safety through set invariance has proven to be a valuable method in various robotics and control applications. This paper introduces a comprehensive framework for the safe probabilistic invariance verification of both discrete- and continuous-time stochastic dynamical systems over an infinite time horizon. The objective is to ascertain the lower and upper bounds of liveness probabilities for a given safe set and set of initial states. The liveness probability signifies the likelihood of the system remaining within the safe set indefinitely, starting from a state in the initial set. To address this problem, we propose optimizations for verifying safe probabilistic invariance in discrete-time and continuous-time stochastic dynamical systems. These optimizations are constructed via either using the Doob's nonnegative supermartingale inequality-based method or relaxing the equations described in [30,32], which can precisely characterize the probability of reaching a target set while avoiding unsafe states. Finally, we demonstrate the effectiveness of these optimizations through several examples using semi-definite programming tools.
Consistency analysis of refined instrumental variable methods for continuous-time system identification in closed-loop
Authors: Rodrigo A. González, Siqi Pan, Cristian R. Rojas, James S. Welsh
Date: 2024-04-13 00:00:00

Refined instrumental variable methods have been broadly used for identification of continuous-time systems in both open and closed-loop settings. However, the theoretical properties of these methods are still yet to be fully understood when operating in closed-loop. In this paper, we address the consistency of the simplified refined instrumental variable method for continuous-time systems (SRIVC) and its closed-loop variant CLSRIVC when they are applied on data that is generated from a feedback loop. In particular, we consider feedback loops consisting of continuous-time controllers, as well as the discrete-time control case. This paper proves that the SRIVC and CLSRIVC estimators are not generically consistent when there is a continuous-time controller in the loop, and that generic consistency can be achieved when the controller is implemented in discrete-time. Numerical simulations are presented to support the theoretical results.