1,721,508 research outputs found
Abstract rule-based argumentation
No full textThis article reviews abstract rule-based approaches to argumentation, in particular the ASPIC+ framework. In ASPIC+ and its predecessors, going back to the seminal work of John Pollock, arguments can be formed by combining strict and defeasible inference rules and conflicts between arguments can be resolved in terms of a preference relation on arguments. This results in abstract argumentation frameworks (a set of arguments with a binary relation of defeat), so that arguments can be evaluated with the theory of abstract argumentation. First the basic ASPIC+ framework is reviewed, possible ways to instantiate it are discussed and how these instantiations can satisfy closure and consistency properties. Then the relation between ASPIC+ and other work in formal argumentation and nonmonotonic logic is discussed, including a review of how other approaches can be reconstructed as instantiations of ASPIC+. Further developments and variants of the basic ASPIC+ framework are also reviewed, including developments with alternative or generalised notions of attack and defeat and variants with further constraints on arguments. Finally, implementations and applications of ASPIC+ are briefly reviewed and some open problems and avenues for further research are discussed
Deontic Dynamic Logic: a Retrospective
No full textIn this paper a retrospective is given on the development of deontic dynamic logic. It first reviews the basic system PDeL as introduced in 1988, with emphasis on conceptual issues and technical choices and properties. It then continues with later developments and applications by ourselves and related work by others. Thus we will see how contrary-to-duties and free choice permissions are treated, and how violations can be handled more expressively, including a way of dealing with red/green states and transitions
Extensions and modifications to explanatory coherence
No full textThagard’s theory of explanatory coherence (TEC) and its implementation ECHO might be considered as the de facto calculus of explanatory coherence. It is an elaborate framework to compare competing scientific theories. Recently, it has become apparent that TEC is also useful as a tool for the analysis of different scenarios in so-called sense-making systems. To this end, it is expedient to discuss a number of extensions and modifications to TEC. This article proposes a number of extensions and modifications to TEC in the context of sense-making systems. The following topics are discussed: input format, representation of false formulas, representation languages, relaxation methods, schemes of coherence, meta-explanations, scenarios, leaking hypotheses, knowledge acquisition, and contextual explanation. The discussion is detailed enough to carry through changes in existing sense-making systems
Decentralized Runtime Norm Enforcement
No full textSmart roads are an electronically enriched form of highways that aim to maximize the throughput and safety of traffic. If a vehicle is not complying with its instructions, then an appropriate reaction such as a fine is required. This gives us two basic tasks for a smart road. On the one hand does it have to monitor the traffic in order to determine the instructions for vehicles and whether they comply with their instructions, on the other hand does it have to process the violations of instructions. In this thesis we view the tasks of a smart road as an example of the more generic task of making sure that agents behave according to preset guidelines. A specification of how agents ought to behave and the measures when they fail to comply, is what we call a norm. In our traffic example we may consider a norm to be comparable with a traffic rule. The task of a smart road can be reformulated as `the enforcement of one or more norms'. The traffic situation on one road may affect the situation on another. Therefore, it is often appropriate to consider norms not in the context of a single smart road but in a network of them. Smart roads have to collaborate in such cases in order to enforce the norms. We call this decentralized enforcement. We are particularly interested in the limitations and possibilities of decentralized norm enforcement when we want to apply it in an application. To this end, we focus specifically on decentralized runtime norm enforcement. Our main conclusions and contributions are as follows. Decentralized runtime norm enforcement is composed of monitoring and control. Monitoring for decentralized runtime norm enforcement can be equated to verifying whether a system satisfies a linear temporal logic (LTL) formula. Several proposals exist for runtime LTL verification, to which we have added two complementary proposals. We also discussed security and robustness for a decentralized monitor. The control task of decentralized runtime norm enforcement is comparable to the control of discrete event systems. We took a runtime controller model from the literature of discrete event control systems and have shown how this model can be reapplied for norm enforcement. A typical property of decentralized enforcement is that multiple controllers can operate in a concurrent manner, such as multiple smart roads that are coordinating traffic concurrently. We describe how the model for controllers can be expanded to the concurrent application of controllers, which results in a collaborative controller. It is important to consider conventional programming paradigms in order to promote the development of agent systems with norm enforcement. We proposed design patterns for object-oriented programming which capture often reoccurring solutions in the agent programming literature. We also showed how an object-oriented implementation can be expanded with norm enforcement using aspect-oriented programming. Finally, we made an example simulation of a smart roads scenario. This simulation illustrates how we may view the task of a smart road as the decentralized runtime enforcement of norms
On direct and indirect probabilistic reasoning in legal proof
No full textIn the academic literature three approaches to rational legal proof are investigated, broadly speaking based, respectively on Bayesian statistics, on scenario construction and on argumentation. In this paper these approaches are discussed in light of a distinction between direct and indirect probabilistic reasoning. Direct probabilistic reasoning directly reasons from evidence to hypotheses, while indirect probabilistic reasoning reasons from hypotheses to evidence (and then back to the hypotheses). While statistical and story-based approaches usually model indirect probabilistic reasoning, argumentation-based approaches usually model direct probabilistic reasoning. It has been suggested that all legal probabilistic reasoning should be indirect, but in this paper it is argued that direct probabilistic reasoning has a rational basis and is, moreover, sometimes easier to perform for judges than indirect probabilistic reasoning. Moreover, direct probabilistic reasoning can be analysed in terms of standard probability theory, resulting in an alternative, non-Bayesian use of the terms "prior" and "posterior" probability and without the need to estimate unconditional probabilities of the hypotheses
Grid Manufacturing: A Cyber-Physical Approach with Autonomous Products and Reconfigurable Manufacturing Machines
No full textEach period of time has its own revolution, and with each revolution comes its own organisational model. We find ourselves in the 4th industrial revolution, where the internet of things connects autonomous embedded systems that live both in the virtual 'cyber' world, and in the real 'physical' world. These so-called Cyber-Physical Systems follow modern organisational models like self-management and can take proactive actions themselves. The thesis zooms in from the Cyber-Physical perspective to manufacturing systems that are both reconfigurable, autonomous, and flexible. This is achieved by developing new methods and using technologies that enable flexibility. However, efficiency has to be improved as well, e.g. by making assembly so flexible that it becomes cost-efficient to automate the production of low quantities of different products: so-called high-mix, low-volume production. The ability to automatically manufacture high-mix, low-volume production will drive the market for mass customisation, and bring about a shorter time to market. In practice, the move for flexibility will be achieved by creating new methods and tools, combining new technologies, and applied testing with simulators and newly-developed manufacturing systems. This thesis start by introducing the concept behind the manufacturing methodology, called 'Grid Manufacturing'. Grid Manufacturing takes place using autonomous entities, i.e. agents for both the equipment and the product itself. Products live in the 'cyber' world even before they are created in the 'physical' world and are aware of how they should be manufactured. They communicate and negotiate with reconfigurable manufacturing machines, called 'equiplets'. The equiplets offer generic services, e.g. pick & place, which a variety of products can use on demand by negotiating with the equiplets. This study focuses on the design and technology behind equiplets specifically and the infrastructure in general that is required to develop such a flexible and reconfigurable manufacturing system. To enable Grid Manufacturing, a whole set of technological challenges has been investigated. Where the main effort was put into the creation of automated flexibility for the manufacturing systems itself. This starts in the Chapter Object Awareness, which introduces an approach to dynamically handle and localise products by combining knowledge from different autonomous systems. The chapter is followed by Chapter Reconfiguration, which shows how products can communicate and control equiplets without being aware of the equiplet hardware configuration. The same chapter also shows how the hardware cannot just be used by a product, but can also be changed, making it possible to adapt the hardware configuration without reprogramming the system. Subsequently, in Chapter Architecture, the study focuses on combining performance and flexibility in a hybrid architecture that is used to control the 'grid' with equiplets, showing a hybrid platform made up of both a Multi-Agent System and the Robot Operating System platform for hardware control. After the architecture is established, the thesis focuses on how the architecture can be used safely, and introduces the control systems and system behaviour to be able to predict the behaviour of the equiplets. Now these fundamental systems for Grid Manufacturing have been covered it is time to continue with Chapter Validation and Utilisation, which looks from a grid perspective and shows how a grid can be used in new ways, with either a heterarchical control — in which all systems are equal — or not, when this is more efficient. The chapter also tests the grid with different simulated cases, to show that reconfiguration and the heterarchical approach can have several benefits
Visually Embodying Well-Typedness of Algebraic Data Structures through Maramafication
No full textThis paper presents a maramafication of an essential part of FPLs: the construction of well-typed algebraic data structures based on type definitions with at most one type parameter. Maramafication means the design of visual ‘twins’ of existing programming constructs using spatial metaphors rooted in common sense or inborn spatial intuition, to achieve self-explanatoriness. This is, among others, useful to considerably reduce the gap between programmers and non-programmers in the creation of programs, for educational purposes or for invoking enthusiasm among non-programmers
Programming multi-agent systems
Full text linkWith the significant advances in the area of autonomous agents and multi-agent systems in the last decade, promising technologies for the development and engineering of multi-agent systems have emerged. The result is a variety of agent-oriented programming languages, development frameworks, execution platforms, and tools that facilitate building and engineering of multi-agent systems. This paper provides an overview of the multi-agent programming research field and explains the aim and characteristics of various multi-agent programming languages and development frameworks. This overview is complemented with a discussion on the current trends and challenges in this research community
Norm-based mechanism design
Full text linkThe increasing presence of autonomous (software) systems in open environments in general, and the complex interactions taking place among them in particular, require flexible control and coordination mechanisms to guarantee desirable overall system level properties without limiting the autonomy of the involved systems. In artificial intelligence, and in particular in the multi-agent systems research field, social laws, norms, and sanctions have been widely proposed as flexible means for coordinating the behaviour of autonomous agents in multi-agent settings. Recently, many languages have been proposed to specify and implement norm-based environments where the behaviour of autonomous agents is monitored, evaluated based on norms, and possibly sanctioned if norms are violated. In this paper, we first introduce a formal setting of multi-agent environments based on concurrent game structures which abstracts from concrete specification languages. We extend this formal setting with norms and sanctions, and show how concepts from mechanism design can be used to formally analyse and verify whether a specific behaviour can be enforced (or implemented) if agents follow their subjective preferences. We relate concepts from mechanism design to our setting, where agents' preferences are modelled by linear time temporal logic (LTL) formulae. This proposal bridges the gap between norms and mechanism design allowing us to formally study and analyse the effect of norms and sanctions on the behaviour of rational agents. The proposed machinery can be used to check whether specific norms and sanctions have the designer's expected effect on the rational agents' behaviour or if a set of norms and sanctions that realise the effect exists at all. We investigate the computational complexity of our framework, focusing on its implementation in Nash equilibria and we show that it is located at the second and third level of the polynomial hierarchy. Despite this high complexity, on the positive side, these results are in line with existing complexity results of related problems. Finally, we propose a concrete executable specification language that can be used to implement multi-agent environments. We show that the proposed specification language generates specific concurrent game structures and that the abstract multi-agent environment setting can be applied to study and analyse the behaviour of multi-agent programs with and without norms
Artificial Intelligence in Health Care and Medicine: A Personalized Approach
Full text linkArtificial Intelligence (AI) is becoming more and more ubiquitous, and AI also invades health care and related fields ever more. We believe this is a good thing. Inspired by work that we have done in various projects at the Alan Turing Institute Almere (ATIA), Delft University of Technology (TUD), Utrecht University (UU), and Vrije University (VU), we’ll review a number of applications of AI in health care and medicine, mainly from a personal viewpoint, expertise and interest. In many of the projects we have worked on there is a shared focus and interest in creating a more personalized approach to health care and medicine. It is this focus on a more personalized health care that we want to highlight in this paper. To this end, we review various examples of work to illustrate and argue that AI, and Social AI in particular, has great potential for improving healthcare and enabling a more personalized approach. We show techniques from Social AI can be effectively applied in developing Behavior Change Management systems, and illustrate its use in related work on data collection for Value-Based Health Care. In particular, we’ll discuss artificial emotions, serious games for healthcare, and artificial companions to assist with the care of patients in a hospital or home setting. These companions are able to monitor the behavior of patients, help them remind of taking medication, but also can have conversations with them giving them the feeling that they are cared for. We argue that these examples of Social AI techniques can be used to enable and improve personalized health care even in times where health care is economized upon like we face in The Netherlands. More generally, in this article we discuss various methods and techniques from AI to do this
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