Reasoning techniques for analysis and refinement of policies for service management

The work described in this technical report falls under the general problem of developing methods that would allow us to engineer software systems that are reliable and would offer a certain acceptable level of quality in their operation. This report shows how the analysis and refinement of policies for Quality of Service can be carried out within logic by exploiting forms of abductive and argumentative reasoning. In particular, it provides two main contributions. The first is an extension of earlier work on the use of abductive reasoning for automatic policy refinement by exploiting the use of integrity constraints within abduction and its integration with constraint solving. This has allowed us to enhance this refinement process in various ways, e.g. supporting parameter values derivation to quantify abstract refinement to specific policies ready to be put in operation, and calculating utility values to determine optimal refined policies. The second contribution is a new approach for modelling and formulating Quality of Service policies, and more general policies for software requirements, as preference policies within logical frameworks of argumentation. This is shown to be a flexible and declarative approach to the analysis of such policies through high-level semantic queries of argumentation, demonstrated here for the particular case of network firewall policies where the logical framework of argumentation allows us to detect anomalies in the firewalls and facilitates the process of their resolution. To our knowledge this is the first time that the link between argumentation and the specification and analysis of requirement policies has been studied

Metalogical Contributions to the Nonmonotonic Theory of Abstract Argumentation

The study of nonmonotonic logics is one mayor field of Artificial Intelligence (AI). The reason why such kind of formalisms are so attractive to model human reasoning is that they allow to withdraw former conclusion. At the end of the 1980s the novel idea of using argumentation to model nonmonotonic reasoning emerged in AI. Nowadays argumentation theory is a vibrant research area in AI, covering aspects of knowledge representation, multi-agent systems, and also philosophical questions. Phan Minh Dung’s abstract argumentation frameworks (AFs) play a dominant role in the field of argumentation. In AFs arguments and attacks between them are treated as primitives, i.e. the internal structure of arguments is not considered. The major focus is on resolving conflicts. To this end a variety of semantics have been defined, each of them specifying acceptable sets of arguments, so-called extensions, in a particular way. Although, Dung-style AFs are among the simplest argumentation systems one can think of, this approach is still powerful. It can be seen as a general theory capturing several nonmonotonic formalisms as well as a tool for solving well-known problems as the stable-marriage problem. This thesis is mainly concerned with the investigation of metalogical properties of Dung’s abstract theory. In particular, we provide cardinality, monotonicity and splitting results as well as characterization theorems for equivalence notions. The established results have theoretical and practical gains. On the one hand, they yield deeper theoretical insights into how this nonmonotonic theory works, and on the other the obtained results can be used to refine existing algorithms or even give rise to new computational procedures. A further main part is the study of problems regarding dynamic aspects of abstract argumentation. Most noteworthy we solve the so-called enforcing and the more general minimal change problem for a huge number of semantics

Second Workshop on Modelling of Objects, Components and Agents

This report contains the proceedings of the workshop Modelling of Objects, Components, and Agents (MOCA'02), August 26-27, 2002.The workshop is organized by the 'Coloured Petri Net' Group at the University of Aarhus, Denmark and the 'Theoretical Foundations of Computer Science' Group at the University of Hamburg, Germany. The homepage of the workshop is: http://www.daimi.au.dk/CPnets/workshop02

Action, Time and Space in Description Logics

Description Logics (DLs) are a family of logic-based knowledge representation (KR) formalisms designed to represent and reason about static conceptual knowledge in a semantically well-understood way. On the other hand, standard action formalisms are KR formalisms based on classical logic designed to model and reason about dynamic systems. The largest part of the present work is dedicated to integrating DLs with action formalisms, with the main goal of obtaining decidable action formalisms with an expressiveness significantly beyond propositional. To this end, we offer DL-tailored solutions to the frame and ramification problem. One of the main technical results is that standard reasoning problems about actions (executability and projection), as well as the plan existence problem are decidable if one restricts the logic for describing action pre- and post-conditions and the state of the world to decidable Description Logics. A smaller part of the work is related to decidable extensions of Description Logics with concrete datatypes, most importantly with those allowing to refer to the notions of space and time

Declarative programming for agent applications

This paper introduces the execution model of a declarative programming language intended for agent applications. Features supported by the language include functional and logic programming idioms, higher-order functions, modal computation, probabilistic computation, and some theorem-proving capabilities. The need for these features is motivated and examples are given to illustrate the central ideas

Concepts of relevance in a semiotic framework applied to ISAD (information systems analysis and design).

Relevance is the critical criterion for valuing information. The usual requirements of valuable information resources are their accuracy, brevity, timeliness and rarity. This thesis points out that relevance has to be explicitly recognised as an important quality of information. Therefore, the theory of signs is adopted to enable a systematic study of the problem of relevance according to the branches of semiotics in order to clarify the concept of information. Relevance has several meanings according to the various disciplinary approaches including phenomenology, law, logic, information science, communication and cognition. These different concepts are discussed and criticised in two chapters. A new approach is proposed in which a universal concept of relevance is considered as an affordance. Therefore, all the approaches to relevance can be applied within the broader approach of the analysis of affordances. This approach not only encompasses all the underlying characteristics of relevance, it is also compatible with the assumptions of the logic of norms and affordances (NORMA). NORMA semantic analysis is used as a basis on which concepts of relevance are applied semiotically. Two case- studies are selected for testing these concepts which results in a guideline for practical application in a semiotic framework. The results from these case-studies confirm the practical importance of these concepts of relevance which can be systematically used in the analysis and design of information systems. It also reaffirms the underlying characteristics of relevance which exist in the context of social reality

Application of intrusion detection system in automatic evidence collection using digital forensics

In network security, Intrusion Detection System (IDS) is one of the popular and effective mechanism to secure the network. The aim of IDS is to offer a layer of protection against unauthorized (or malicious) uses of systems by sensing the vulnerability in the system or misuse of a security policy, and alerts system administrator to an ongoing (or recent) attack. IDSs function is limited to detect the intrusion and respond to administrator about the intrusion by monitoring the system continuously. IDS is not able to preserve evidence about the intrusion, which makes it difficult to see the damage in the system and gather information about the attack and hence make it impossible to catch the intruder. Although evidence can be collected from IDS’s and system log files, but integrity, reliability, and completeness of such evidence are doubtful as log files can also be altered by intruder. In order to preserve evidence in its original form we have proposed “Application of Intrusion Detection System in automatic Evidence Collection using Digital Forensics”. In our model whenever an intrusion is detected, IDS notify the administrator by sending an alert as well as activate the digital forensic tool to capture the current state of the system. This captured system image contains all the information of the system of the time when attack was taking place. Hence such image can be used as evidence in legal proceeding. We used both signature based IDS and anomaly based IDS in the work and observe that signature based IDS is not able to detect novel threats while anomaly based IDS is able to detect such threats

Sixth Workshop and Tutorial on Practical Use of Coloured Petri Nets and the CPN Tools Aarhus, Denmark, October 24-26, 2005

This booklet contains the proceedings of the Sixth Workshop on Practical Use of Coloured Petri Nets and the CPN Tools, October 24-26, 2005. The workshop is organised by the CPN group at the Department of Computer Science, University of Aarhus, Denmark. The papers are also available in electronic form via the web pages: http://www.daimi.au.dk/CPnets/workshop0

The psychological origins of the Hard Problem: How our consciousness is shaping the neuroscience of consciousness

The field of consciousness studies contains a substantial number of coexisting neurocognitive theories of consciousness. These theories vary in their initial definitions of what consciousness is, biasing scientific methods and measurement of the phenomenon, resulting in a divided science. Definitions of consciousness tend to vary along two lines: Either consciousness is seemingly reducible to physical and functional processes, indicating what is called access consciousness; or it constitutes a seemingly irreducible experience, indicating phenomenal consciousness. These two types of definitions correspond to two opposing camps on what is referred to as the hard problem of consciousness, also called the explanatory gap. While much effort has been spent by each camp either criticizing or defending the hard problem, little work has been done to explain why the two camps vary along these lines. In other words, there is a gap between our positions on the explanatory gap, which I label the “meta-gap”. In the current paper I contribute to bridging the meta-gap by attempting to explain and reconcile this basic disagreement in the field. By performing targeted literature searches, I answer seven research questions which serve as stepping stones to take us from problematic features of the field, to individual differences between researchers as a reason for these problems. My analysis of these individual differences results in two hypothesized psychological constructs: Internal and external explanatory focus. I conclude by indicating that solving the meta-gap involves becoming aware of our individual dispositions towards choosing different explanatory targets for consciousness.Masteroppgave i psykologiMAPSYK360INTL-HFINTL-KMDINTL-SVINTL-JUSMAPS-PSYKINTL-MNINTL-MEDINTL-PSY