Genre
Embedding Data within Knowledge Spaces
Myers, James D., Futrelle, Joe, Gaynor, Jeff, Plutchak, Joel, Bajcsy, Peter, Kastner, Jason, Kotwani, Kailash, Lee, Jong Sung, Marini, Luigi, Kooper, Rob, McGrath, Robert E., McLaren, Terry, Rodriguez, Alejandro, Liu, Yong
The promise of e-Science will only be realized when data is discoverable, accessible, and comprehensible within distributed teams, across disciplines, and over the long-term - without reliance on out-of-band (non-digital) means. We have developed the open-source Tupelo semantic content management framework and are employing it to manage a wide range of e-Science entities (including data, documents, workflows, people, and projects) and a broad range of metadata (including provenance, social networks, geospatial relationships, temporal relations, and domain descriptions). Tupelo couples the use of global identifiers and resource description framework (RDF) statements with an aggregatable content repository model to provide a unified space for securely managing distributed heterogeneous content and relationships. The Tupelo framework includes an HTTPbased data/metadata management protocol, application programming interfaces, and user interface widgets which have been incorporated into NCSA's portal and workflow tools and is a key component in recent work creating dynamic digital observatories (digital watersheds) that combine observational and modeled information. Tupelo also supports specialized indexes and inference logic (computation) relevant to metadata including geospatial location and provenance. This additional capability creates a powerful knowledge space that can map between disciplinary conceptual models and between the storage and data organization choices made by different e-Science organizations.
Graphical Reasoning in Compact Closed Categories for Quantum Computation
Compact closed categories provide a foundational formalism for a variety of important domains, including quantum computation. These categories have a natural visualisation as a form of graphs. We present a formalism for equational reasoning about such graphs and develop this into a generic proof system with a fixed logical kernel for equational reasoning about compact closed categories. Automating this reasoning process is motivated by the slow and error prone nature of manual graph manipulation. A salient feature of our system is that it provides a formal and declarative account of derived results that can include `ellipses'-style notation. We illustrate the framework by instantiating it for a graphical language of quantum computation and show how this can be used to perform symbolic computation.
Elicitation of Factored Utilities
Braziunas, Darius (University of Toronto) | Boutilier, Craig (University of Toronto)
The effective tailoring of decisions to the needs and desires of specific users requires automated mechanisms for preference assessment. We provide a brief overview of recent direct preference elicitation methods: these methods ask users to answer (ideally, a small number of) queries regarding their preferences and use this information to recommend a feasible decision that would be (approximately) optimal given those preferences. We argue for the importance of assessing numerical utilities rather than qualitative preferences, and survey several utility elicitation techniques from artificial intelligence, operations research, and conjoint analysis.
Preferences in Interactive Systems: Technical Challenges and Case Studies
Peintner, Bart (SRI International) | Viappiani, Paolo (University of Toronto) | Yorke-Smith, Neil (SRI International)
Interactive artificial intelligence systems employ preferences in both their reasoning and their interaction with the user. This survey considers preference handling in applications such as recommender systems, personal assistant agents, and personalized user interfaces. We survey the major questions and approaches, present illustrative examples, and give an outlook on potential benefits and challenges.
Preferences and Nonmonotonic Reasoning
Brewka, Gerhard (University of Kentucky) | Niemela, Ilkka | Truszczynski, Miroslaw
We give an overview of the multifaceted relationship between nonmonotonic logics and preferences. We discuss how the nonmonotonicity of reasoning itself is closely tied to preferences reasoners have on models of the world or, as we often say here, possible belief sets. Selecting extended logic programming with the answer-set semantics as a "generic" nonmonotonic logic, we show how that logic defines preferred belief sets and how preferred belief sets allow us to represent and interpret normative statements. Conflicts among program rules (more generally, defaults) give rise to alternative preferred belief sets. We discuss how such conflicts can be resolved based on implicit specificity or on explicit rankings of defaults. Finally, we comment on formalisms which explicitly represent preferences on properties of belief sets. Such formalisms either build preference information directly into rules and modify the semantics of the logic appropriately, or specify preferences on belief sets independently of the mechanism to define them.
Preferences in Constraint Satisfaction and Optimization
Rossi, Francesca (University of Padova) | Venable, Kristen Brent | Walsh, Toby
In this case, all PCs will be considered, but some will be more preferred than others. Such concepts can be expressed in either a qualitative or a quantitative way. Preferences and constraints are closely related notions, since preferences can be seen as a form of "tolerant" constraints. For this reason, there are several constraint-based frameworks to model preferences. One of the most general frameworks, based on soft constraints (Meseguer, Rossi, and Schiex 2006), extends the classical constraint formalism to model preferences in a quantitative way, by expressing several degrees of satisfaction that can be either totally or partially ordered. When there are both levels of satisfaction and levels of rejection, preferences are bipolar and can be modeled by extending the soft constraint formalism (Bistarelli et al. 2006). Preferences can also be modeled in a qualitative way (also called ordinal), that is, by pairwise comparisons. In this case, soft constraints (or their extensions) are not suitable.
Preference Handling in Combinatorial Domains: From AI to Social Choice
Chevaleyre, Yann (LAMSADE, Université Paris-Dauphine) | Endriss, Ulle (ILLC, University of Amsterdam) | Lang, Jérôme (LAMSADE, Université Paris-Dauphine) | Maudet, Nicolas (LAMSADE, Université Paris-Dauphine)
In both individual and collective decision making, the space of alternatives from which the agent (or the group of agents) has to choose often has a combinatorial (or multi-attribute) structure. We give an introduction to preference handling in combinatorial domains in the context of collective decision making, and show that the considerable body of work on preference representation and elicitation that AI researchers have been working on for several years is particularly relevant. After giving an overview of languages for compact representation of preferences, we discuss problems in voting in combinatorial domains, and then focus on multiagent resource allocation and fair division. These issues belong to a larger field, known as computational social choice, that brings together ideas from AI and social choice theory, to investigate mechanisms for collective decision making from a computational point of view. We conclude by briefly describing some of the other research topics studied in computational social choice.