4222588
Logical Foundations of Negotiation: Outcome, Concession, and Adaptation
This paper provides a logical framework for negotiation between agents that are assumed to be rational, cooperative and truthful. We present a characterisation of the permissible outcomes of a process of negotiation in terms of a set of rationality postulates, as well as a method for constructing exactly the rational outcomes. The framework is extended by describing two modes of negotiation from which an outcome can be reached. In the concessionary mode, agents are required to weaken their demands in order to accommodate the demands of others. In the adaptationist mode, agents are required to adapt to the demands of others in some appropriate fashion. Both concession and adaptation are characterised in terms of rationality postulates. We also provide methods for constructing exactly the rational concessions, as well as the rational adaptations. The central result of the paper is the observation that the outcomes obtained from the concessionary and adaptationist modes both correspond to the rational outcomes. We conclude by pointing out the links between negotiation and AGM belief change, and providing a glimpse of how this may be used to define a notion of preference-based negotiation.
1871739
Sydney OWL Syntax - towards a Controlled Natural Language Syntax for OWL 1.1
This paper describes a proposed new syntax that can be used to write and read OWL ontologies in Controlled Natural Language (CNL): a well-defined subset of the English language. Following the lead of Manchester OWL Syntax in making OWL more accessible for non-logicians, and building on the previous success of Schwitter’s PENG (Processable English), the proposed Sydney OWL Syntax enables two-way translation and generation of grammatically correct full English sentences to and from OWL 1.1 functional syntax. Used in conjunction with OWL tools, it is designed to facilitate ontology construction and editing by enabling authors to write an OWL ontology in a defined subset of English. It also improves readability and understanding of OWL statements or whole ontologies, by enabling them to be read as English sentences. It is hoped that by providing the option of an intuitive, easy to use English syntax which requires no specialized knowledge, the broader community will be far more likely to develop and benefit from Semantic Web applications. This paper is a discussion paper covering the scope, design, and examples of Sydney OWL Syntax in use, and the authors invite feedback on all aspects of the proposal via email to krr.sydneysyntax@cse.unsw.edu.au. Working drafts of the full specification are available at http://www.ics.mq.edu.au/~rolfs/sos.
15894793
Implementing Iterated Belief Change Via Prime Implicates
Belief change is concerned with modelling the way in which an idealised (rational) reasoner maintains their beliefs and the way in which those beliefs are modified as the reasoner acquires new information. The AGM [1,3,5] framework is the most widely cited belief change methodology in the literature. It models the reasoner’s belief state as a set of sentences that is logically closed under deduction and provides for three belief change operations: expansion, contraction and revision. Each of the AGM belief change operations is motivated by principles of rationality that are formalised by way of rationality postulates.
1029481
Modelling Object Typicality in Description Logics
We present a semantic model of typicality of concept members in description logics (DLs) that accords well with a binary, globalist cognitive model of class membership and typicality. We define a general preferential semantic framework for reasoning with object typicality in DLs. We propose the use of feature vectors to rank concept members according to their defining and characteristic features, which provides a modelling mechanism to specify typicality in composite concepts.
1613464
Merging Epistemic States
Intelligent agents are often faced with the problem of trying to merge possibly conflicting pieces of information obtained from different sources into a consistent view of the world. We propose a framework for the modelling of such merging operations with roots in the work of Spohn [14]. Unlike most approaches we focus on the merging of epistemic states, not knowledge bases. We construct a number of plausible merging operations and measure them against various properties that merging operations ought to satisfy. Finally, we discuss the connection between merging and the use of infobases [9], [10].
10175705
Next Steps in Propositional Horn Contraction
Standard belief contraction assumes an underlying logic containing full classical propositional logic, but there are good reasons for considering contraction in less expressive logics. In this paper we focus on Horn logic. In addition to being of interest in its own right, our choice is motivated by the use of Horn logic in several areas, including ontology reasoning in description logics. We consider three versions of contraction: entailment-based and inconsistency-based contraction (e-contraction and i-contraction, resp.), introduced by Delgrande for Horn logic, and package contraction (p-contraction), studied by Fuhrmann and Hansson for the classical case. We show that the standard basic form of contraction, partial meet, is too strong in the Horn case. We define more appropriate notions of basic contraction for all three types above, and provide associated representation results in terms of postulates. Our results stand in contrast to Delgrande's conjectures that orderly maxichoice is the appropriate contraction for both e- and i-contraction. Our interest in p-contraction stems from its relationship with an important reasoning task in ontological reasoning: repairing the subsumption hierarchy in EL. This is closely related to p-contraction with sets of basic Horn clauses (Horn clauses of the form p → q). We show that this restricted version of p-contraction can also be represented as i-contraction.
2586073
Robustness to Code and Data Deletion in Autocatalytic Quines
Software systems nowadays are becoming increasingly complex and vulnerable to all sorts of failures and attacks. There is a rising need for robust self-repairing systems able to restore full functionality in the face of internal and external perturbations, including those that affect their own code base. However, it is difficult to achieve code self-repair with conventional programming models. 
 
We propose and demonstrate a solution to this problem based on self-replicating programs in an artificial chemistry. In this model, execution proceeds by chemical reactions that modify virtual molecules carrying code and data. Self-repair is achieved by what we call autocatalytic quines : programs that permanently reproduce their own code base. The concentration of instructions reflects the health of the system, and is kept stable by the instructions themselves. We show how the chemistry of such programs enables them to withstand arbitrary amounts of random code and data deletion, without affecting the results of their computations.
13787606
Identification of cylin-dependent kinase 1 inhibitors of a new chemical type by structure-based design and database searching
We have selected cyclin-dependent kinase 1 (CDK1), an enzyme participating in the regulation of the cell cycle, as a target in our efforts to discover new antitumor agents. By exploiting available structural information, we designed an ATP-site directed ligand scaffold that allowed us to identify 4-(3-methyl-1,4-dioxo-1,4-dihydro-naphthalen-2-ylamino)-benzenesulfonamide as a new potent inhibitor of CDK1 in a subsequent database search. The synthesis and testing of some analogues confirmed the interest of this class of compounds as novel CDK1 inhibitors.
9042273
Tactic-Based Optimized Compilation of Functional Programs
Within a framework of correct code-generation from HOL-specifications, we present a particular instance concerned with the optimized compilation of a lazy language (called MiniHaskell) to a strict language (called MiniML). 
 
Both languages are defined as shallow embeddings into denotational semantics based on Scott's cpo's, leading to a derivation of the corresponding operational semantics in order to cross-check the basic definitions. 
 
On this basis, translation rules from one language to the other were formally derived in Isabelle/HOL. Particular emphasis is put on the optimized compilation of function applications leading to the side-calculi inferring e.g. strictness of functions. 
 
The derived rules were grouped and set-up as an instance of our generic, tactic-based translator for specifications to code.
747572
Multimedia synchronization techniques: experiences based on different system structures
Introduction "Multimedia synchronization" is needed to ensure a temporal ordering of events in multimedi a systems . There are two parts to this problem : the definition of temporal relationships among audio , video, and other data ; and the delivery of the data in accordance with these relationships . It i s important to distinguish between liveand synthetic-synchronization . Live-synch, deals with th e presentation of information in the same order as it was originally collected . For synthetic-synch . various pieces of information must be properly ordered and synchronized in time . Based on th e experiences in DiME and HeiTS, we document the implications of using a hybrid or a unified syste m structures on the required techniques for implementing synchronization .
1383149
An Artificial Chemistry for Networking
Chemical computing models have been proposed since the 1980ies for expressing concurrent computations in elegant ways for shared memory systems. In this paper we look at the distributed case of network protocol execution for which we developed an online artificial chemistry. In this chemistry, data packets become molecules which can interact with each other, yielding computation networks comparable to biological metabolisms. Using this execution support, we show how to compute an average over arbitrary networking topologies and relate it to traditional forms of implementing load balancing. Our long-term interest lies in the robust implementation, operation and evolution of network protocols, for which artificial chemistries provide a promising basis.