Planning is a challenging research area since the early days of Artificial Intelligence. The planning problem is the task of finding a sequence of actions leading an agent from a given initial state to a desired goal state. Whereas classical planning adopts restricting assumptions such as complete knowledge about the initial state and deterministic action effects, in real world scenarios we often have to face incomplete knowledge and non-determinism. Classical planning languages and algorithms do not take these facts into account. So, there is a strong need for formal languages describing such non-classical planning problems on the one hand and for (declarative) methods for solving these problems on the other hand.In this thesis, we present the action language Kc, which is based on flexible action languages from the knowledge representation community and extends these by useful concepts from logic programming.We define two basic semantics for this language which reflect optimistic and secure (i.e. sceptical) plans in presence of incomplete information or nondeterminism. These basic semantics are furthermore extended to planning with action costs, where each action can have an assigned cost value. Here, we address optimal plans as well as plans which stay within a certain overall cost limit.Next, we develop efficient (i.e. polynomial) transformations from planning problems described in our language Kc to disjunctive logic programs which are then evaluated under the so-called Answer Set Semantics. In this context, we introduce a general new method for problem solving in Answer Set Programming (ASP) which takes the genuine "guess and check" paradigm in ASP into account and allows us to integrate separate "guess" and "check" programs into a single logic program. Based on these methods, we have implemented the planning system DLVK. We discuss problem solving and knowledge representation in Kc using DLVK by means of several examples. The proposed methods and the DLVK system are also evaluated experimentally and compared against related approaches. Finally, we present a practical application scenario from the area of design and monitoring of multi-agent systems. As we will see, this monitoring approach is not restricted to our particular formalism. / Austrian Science Funds (FWF)

This thesis analyzes the kinds of verbal and nonverbal signals elites manifest to show leadership qualities. Launching from Max Weber’s conceptual framework of charisma as a power term and Harold Lasswell’s study of propaganda, this study takes a multidisciplinary approach to studying political leadership with elements of communication methodology and an ontological basis in evolutionary psychology. The study’s goal is to offer a framework for defining and evaluating the diverse signal patterns employed by political elites in three real-life situations. These are the Malta Summit, the 1992 Virginia Presidential Debate, and the 2012 South Carolina Republican Presidential Primary. The cases were chosen because they display a diverse set of signal variations during different types of interactions. The three case studies are evaluated by measuring frequency and patterns of occurrence of the five different interaction constructs (indicator of interest, indicator of disinterest, demonstration of high value, demonstration of low value, and compliance testing) to explain different interaction patterns. A simple frequency distribution of the different signals during a given interaction is used to display the empirical findings and to compare patterns across the case studies. This study reveals that the presence of DLV (demonstration of low value) signals weaken an elite’s position in relation to other elites and the public while the presence of DHV (demonstration of high value) signals strengthen an elite’s position. It is largely the presence, absence, and frequency of these two signals that determines who conveys leadership qualities effectively regardless of leadership style. Studying the signaling patterns of political elites would allow scholars to understand better the kinds of signal patterns and signal frequencies that are used in different types of leadership styles and norm ranges for signals including for political elites belonging to different cultures and subcultures