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 University of Twente


Robust Control for Dynamical Systems with Non-Gaussian Noise via Formal Abstractions

Journal of Artificial Intelligence Research

Controllers for dynamical systems that operate in safety-critical settings must account for stochastic disturbances. Such disturbances are often modeled as process noise in a dynamical system, and common assumptions are that the underlying distributions are known and/or Gaussian. In practice, however, these assumptions may be unrealistic and can lead to poor approximations of the true noise distribution. We present a novel controller synthesis method that does not rely on any explicit representation of the noise distributions. In particular, we address the problem of computing a controller that provides probabilistic guarantees on safely reaching a target, while also avoiding unsafe regions of the state space. First, we abstract the continuous control system into a finite-state model that captures noise by probabilistic transitions between discrete states. As a key contribution, we adapt tools from the scenario approach to compute probably approximately correct (PAC) bounds on these transition probabilities, based on a finite number of samples of the noise. We capture these bounds in the transition probability intervals of a so-called interval Markov decision process (iMDP). This iMDP is, with a user-specified confidence probability, robust against uncertainty in the transition probabilities, and the tightness of the probability intervals can be controlled through the number of samples. We use state-of-the-art verification techniques to provide guarantees on the iMDP and compute a controller for which these guarantees carry over to the original control system. In addition, we develop a tailored computational scheme that reduces the complexity of the synthesis of these guarantees on the iMDP. Benchmarks on realistic control systems show the practical applicability of our method, even when the iMDP has hundreds of millions of transitions.


JudgeD: A Probabilistic Datalog with Dependencies

AAAI Conferences

We present JudgeD, a probabilistic datalog. A JudgeD program defines a distribution over a set of traditional datalog programs by attaching logical sentences to clauses to implicitly specify traditional data programs. Through the logical sentences, JudgeD provides a novel method for the expression of complex dependencies between both rules and facts. JudgeD is implemented as a proof-of-concept in the language Python. The implementation allows connection to external data sources, and features both a Monte Carlo probability approximation as well as an exact solver supported by BDDs. Several directions for future work are discussed and the implementation is released under the MIT license.


Long-Term Acceptance of Social Robots in Domestic Environments: Insights from a User’s Perspective

AAAI Conferences

The increasing mere presence of robots in everyday life does not automatically result in gradual acceptance of these systems by human users. Over the past years, we have conducted several studies with the goal to provide insight into the long-term process of social robots in domestic environments. This paper presents our overall conclusions from the combined findings of our multiple studies on social robot acceptance. We will provide insights from a user’s perspective of what makes robots social, describe a phased framework of the long-term process of robot acceptance, present some key factors for social robot acceptance, offer guidelines to build better sociable robots, and provide some recommendations for conducting research in domestic environments. With sharing our experiences with conducting (long-term) user studies in domestic environments, we aim to serve to push this sub-field of HRI in real-world contexts forward and thereby the community at large.



Report on the 2013 Affective Computing and Intelligent Interaction Conference (ACII 2013)

AI Magazine

Report on the 2013 Affective Computing and Intelligent Interaction Conference (ACII 2013) Abstract The 2013 Affective Computing and Intelligent Interaction Conference (ACII 2013)- was held in Geneva, Switzerland, September 2-5, 2013. The 2013 Affective Computing and Intelligent Interaction Conference (ACII 2013)- was held in Geneva, Switzerland, September 2-5, 2013.


Report on the 2013 Affective Computing and Intelligent Interaction Conference (ACII 2013)

AI Magazine

Under the auspices of the Humaine Association (now called the Association for the Advancement of Affective Computing, AAAC), the ACII conference series has become an important international forum for research on affective human-machine interaction and intelligent affective systems. Affect is a phenomenon of substantial importance in most if not all of human activities. This ACII conference therefore strived to emphasize the humanistic side of affective computing by promoting research at the crossroads between engineering and human sciences, including biological, social, and cultural aspects of human life. This has been exemplified by conference topics as varied as computerized psychological emotional modeling; art and cinema studies; gaming; learning; depression, stress, and anxiety management; robots, avatars, and virtual worlds; social media analysis; pattern recognition, classification, and data mining; real-time and embedded affective systems; and others. All have in common affect and emotions, with an emphasis on a computational view of emotion.


Towards Territorial Privacy in Smart Environments

AAAI Conferences

Territorial privacy is an old concept for privacy of the personal space dating back to the 19th century. Despite its former relevance, territorial privacy has been neglected in recent years, while privacy research and legislation mainly focused on the issue of information privacy. However, with the prospect of smart and ubiquitous environments, territorial privacy deserves new attention. Walls, as boundaries between personal and public spaces, will be insufficient to guard territorial privacy when our environments are permeated with numerous computing and sensing devices, that gather and share real-time information about us. Territorial privacy boundaries spanning both the physical and virtual world are required for the demarcation of personal spaces in smart environments. In this paper, we analyze and discuss the issue of territorial privacy in smart environments. We further propose a real-time user-centric observation model to describe multimodal observation channels of multiple physical and virtual observers. The model facilitates the definition of a territorial privacy boundary by separating desired from undesired observers, regardless of whether they are physically present in the user’s private territory or virtually participating in it. Moreover, we outline future research challenges and identify areas of work that require attention in the context of territorial privacy in smart environments.