this paper we introduce Prohairetic Deontic Logic (PDL), a preference-based

. Deontic logic is characterized by the distinction between the actual and the ideal. In this article we discuss the situation where the actual deviates from the ideal, where obligations are violated. Nonmonotonic logics can be very helpful for the formalization of deontic reasoning, in particular to infer moral cues. It has been argued that the problems related to violated obligations, e.g. the Chisholm `Paradox', are just instances of problems of defeasible reasoning. We disagree with this claim since we will argue that there is a fundamental difference between a violated and a defeated obligation. In this article, we analyzeviolated obligations in Horty's nonmonotonic framework. We extend his definition of deontic consequence in such a way that it covers violated obligations and we give a solution to deal with conflicts between violability and defeasibility. 1 Introduction Deontic logic is characterized by the distinction between what is the case and what should be the case, betwee...

this paper, however, that the techniques of nonmonotonic logic may provide a better theoretical framework---at least for the formalization of commonsense normative reasoning---than the usual modal treatment. After reviewing some standard approaches to deontic logic, I focus on two areas in which nonmonotonic techniques promise improved understanding: reasoning in the presence of conflicting obligations, and reasoning with conditional obligations. 2 Modal techniques in deontic logic

Abstract. People often need to reason about policy changes before they are adopted. For example, suppose a website manager knows that users want to enter her site without going through the welcome page. To decide whether or not to permit this, the wise manager will consider the consequences of modifying the policies (e.g., would this allow users to bypass advertisements and legal notices?). Similiarly, people often need to compare policy sets. For example, consider a person who wants to buy health insurance. Before choosing a provider, the customer will want to compare the different policies. In other words, the customer wants to reason about the effect of choosing one policy set over another. We introduce a logic, based on propositional dynamic logic, in which these tasks can be done. We give a sound and complete axiomatization for our logic, and also show that it is decidable. More precisely, the satisfiability problem is decidable in nondeterministic exponential time. 1

Organizations are continuously under the pressure of change, and develop through a process of social construction, based on its individuals ’ current perception of the world. Most organizations have a partly computerized information system to support adequate action so that perceived value addition may be achieved within this environment. It is regarded that the evolutionary aspects of computerized information systems support are insufficiently covered by traditional approaches and tools. In addition to this, the process of social construction of the organizational reality is neglected in most development methodologies. In this thesis, we have developed a methodological framework coined system devtenance for the application of conceptual models in developing and maintaining portfolios of computerized information systems in organizations, taking continuous evolution and social construction into account. A survey-investigation has been performedamong Norwegian organizations to get a better impression of current methodologies and perceived problems with computerized information systems support in organizations. The results from the investigation are compared with previous

this paper we discuss when and how to use deontic logic in multi agent systems

Deontic logic, the logic of obligations and permissions, is plagued by several paradoxes that have to be understood before deontic logic can be used as a knowledge representation language. In this paper we extend the temporal analysis of Chisholm's paradox using a deontic logic that combines temporal and preferential notions. 0 Introduction Deontic logic is a modal logic in which Op is read as `p ought to be (done).' Deontic logic has traditionally been used by philosophers to analyze the structure of the normative use of language. In the eighties deontic logic had a revival, when it was discovered by computer scientists that this logic can be used for the formal speciøcation and validation of a wide variety of topics in computer science (for an overview and further references see (Wieringa & Meyer 1993)). For example, deontic logic can be used to formally specify soft constraints in planning and scheduling problems as norms. The advantage is that norms can be violated without creati...

In this paper we discuss the role that deontic logic plays in the specification of information systems, either because constraints on the systems directly concern norms or, and even more importantly, system constraints are considered ideal but violable (so-called ‘soft ’ constraints). To overcome the traditional problems with deontic logic (the so-called paradoxes), we first state the importance of distinguishing between ought-to-be and ought-to-do constraints and next focus on the most severe paradox, the so-called Chisholm paradox, involving contrary-to-duty norms. We present a multi-modal extension of standard deontic logic (SDL) to represent the ought-to-be version of the Chisholm set properly. For the ought-to-do variant we employ a reduction to dynamic logic, and show how the Chisholm set can be treated adequately in this setting. Finally we discuss a way of integrating both ought-to-be and ought-to-do reasoning, enabling one to draw conclusions from ought-to-be constraints to ought-to-do ones, and show by an example the use(fulness) of this. 1. Introduction: Soft Constraints

this paper and we take it up again in the discussion at the end of this paper

Since the agent paradigm emerged, agent researchers have faced the challenge of build-ing open societies in which heterogeneous and independently designed entities can work towards similar or different ends. Open societies involve agents that do not necessarily share the same interests, that do not know and might not trust each other, but that can work together and help each other. One of the key omissions in the computational rep-resentation of open societies relates to the need for norms in multi-agent systems, that help to cope with the heterogeneity, the autonomy and the diversity of interests among their members. This also requires agents that can reason about norms because their par-ticipation in a society, rather than predefined, must be voluntary. So, these agents must understand why norms should be adopted and complied with, and why the authority and the power of agents in a society must be respected. This thesis addresses both the in-troduction of norms in systems of autonomous agents, and the modelling of agents that can reason about norms. The thesis makes three main contributions. First, it develops a framework of norma-tive concepts that enables agents to reason about norms and the society in which they participate. Second, it provides the means for agents to identify situations of power, and to use these powers both for the satisfaction of their goals and to understand why the goals of other agents must be satisfied. This is required since agents in an open soci-ety must interact with other agents which are also autonomous, and power represents a means to influence them. Third, this thesis provides models for agents that adopt and comply with norms not as an end, but as the result of a deliberation process in which their goals and motivations are taken into account. This enables agents to voluntarily decide whether participating in a society is important for the achievement of their goals.