The Role of preferences in logic programming: nonmonotonic reasoning, user preferences, decision under uncertainty

Intelligent systems that assist users in fulfilling complex tasks need a concise and processable representation of incomplete and uncertain information. In order to be able to choose among different options, these systems also need a compact and processable representation of the concept of preference. Preferences can provide an effective way to choose the best solutions to a given problem. These solutions can represent the most plausible states of the world when we model incomplete information, the most satisfactory states of the world when we express user preferences, or optimal decisions when we make decisions under uncertainty. Several domains, such as, reasoning under incomplete and uncertain information, user preference modeling, and qualitative decision making under uncertainty, have benefited from advances on preference representation. In the literature, several symbolic approaches of nonclassical reasoning have been proposed. Among them, logic programming under answer set semantics offers a good compromise between symbolic representation and computation of knowledge and several extensions for handling preferences. Nevertheless, there are still some open issues to be considered in logic programming. In nonmonotonic reasoning, first, most approaches assume that exceptions to logic program rules are already specified. However, sometimes, it is possible to consider implicit preferences based on the specificity of the rules to handle incomplete information. Secondly, the joint handling of exceptions and uncertainty has received little attention: when information is uncertain, the selection of default rules can be a matter of explicit preferences and uncertainty. In user preference modeling, although existing logic programming specifications allow to express user preferences which depend both on incomplete and contextual information, in some applications, some preferences in some context may be more important than others. Furthermore, more complex preference expressions need to be supported. In qualitative decision making under uncertainty, existing logic programming-based methodologies for making decisions seem to lack a satisfactory handling of preferences and uncertainty. The aim of this dissertation is twofold: 1) to tackle the role played by preferences in logic programming from different perspectives, and 2) to contribute to this novel field by proposing several frameworks and methods able to address the above issues. To this end, we will first show how preferences can be used to select default rules in logic programs in an implicit and explicit way. In particular, we propose (i) a method for selecting logic program rules based on specificity, and (ii) a framework for selecting uncertain default rules based on explicit preferences and the certainty of the rules. Then, we will see how user preferences can be modeled and processed in terms of a logic program (iii) in order to manage user profiles in a context-aware system and (iv) in order to propose a framework for the specification of nested (non-flat) preference expressions. Finally, in the attempt to bridge the gap between logic programming and qualitative decision under uncertainty, (v) we propose a classical- and a possibilistic-based logic programming methodology to compute an optimal decision when uncertainty and preferences are matters of degrees.Els sistemes intel.ligents que assisteixen a usuaris en la realització de tasques complexes necessiten una representació concisa i formal de la informació que permeti un raonament nomonòton en condicions d’incertesa. Per a poder escollir entre les diferents opcions, aquests sistemes solen necessitar una representació del concepte de preferència. Les preferències poden proporcionar una manera efectiva de triar entre les millors solucions a un problema. Aquestes solucions poden representar els estats del món més plausibles quan es tracta de modelar informació incompleta, els estats del món més satisfactori quan expressem preferències de l’usuari, o decisions òptimes quan estem parlant de presa de decisió incorporant incertesa. L’ús de les preferències ha beneficiat diferents dominis, com, el raonament en presència d’informació incompleta i incerta, el modelat de preferències d’usuari, i la presa de decisió sota incertesa. En la literatura, s’hi troben diferents aproximacions al raonament no clàssic basades en una representació simbòlica de la informació. Entre elles, l’enfocament de programació lògica, utilitzant la semàntica de answer set, ofereix una bona aproximació entre representació i processament simbòlic del coneixement, i diferents extensions per gestionar les preferències. No obstant això, en programació lògica es poden identificar diferents problemes pel que fa a la gestió de les preferències. Per exemple, en la majoria d’enfocaments de raonament no-monòton s’assumeix que les excepcions a default rules d’un programa lògic ja estan expressades. Però de vegades es poden considerar preferències implícites basades en l’especificitat de les regles per gestionar la informació incompleta. A més, quan la informació és també incerta, la selecció de default rules pot dependre de preferències explícites i de la incertesa. En el modelatge de preferències del usuari, encara que els formalismes existents basats en programació lògica permetin expressar preferències que depenen d’informació contextual i incompleta, en algunes aplicacions, donat un context, algunes preferències poden ser més importants que unes altres. Per tant, resulta d’interès un llenguatge que permeti capturar preferències més complexes. En la presa de decisions sota incertesa, les metodologies basades en programació lògica creades fins ara no ofereixen una solució del tot satisfactòria pel que fa a la gestió de les preferències i la incertesa. L’objectiu d’aquesta tesi és doble: 1) estudiar el paper de les preferències en la programació lògica des de diferents perspectives, i 2) contribuir a aquesta jove àrea d’investigació proposant diferents marcs teòrics i mètodes per abordar els problemes anteriorment citats. Per a aquest propòsit veurem com les preferències es poden utilitzar de manera implícita i explícita per a la selecció de default rules proposant: (i) un mètode basat en l’especificitat de les regles, que permeti seleccionar regles en un programa lògic; (ii) un marc teòric per a la selecció de default rules incertes basat en preferències explícites i la incertesa de les regles. També veurem com les preferències de l’usuari poden ser modelades i processades usant un enfocament de programació lògica (iii) que suporti la creació d’un mecanisme de gestió dels perfils dels usuaris en un sistema amb reconeixement del context; (iv) que permeti proposar un marc teòric capaç d’expressar preferències amb fòrmules imbricades. Per últim, amb l’objectiu de disminuir la distància entre programació lògica i la presa de decisió amb incertesa proposem (v) una metodologia basada en programació lògica clàssica i en una extensió de la programació lògica que incorpora lògica possibilística per modelar un problema de presa de decisions i per inferir una decisió òptima.Los sistemas inteligentes que asisten a usuarios en tareas complejas necesitan una representación concisa y procesable de la información que permita un razonamiento nomonótono e incierto. Para poder escoger entre las diferentes opciones, estos sistemas suelen necesitar una representación del concepto de preferencia. Las preferencias pueden proporcionar una manera efectiva para elegir entre las mejores soluciones a un problema. Dichas soluciones pueden representar los estados del mundo más plausibles cuando hablamos de representación de información incompleta, los estados del mundo más satisfactorios cuando hablamos de preferencias del usuario, o decisiones óptimas cuando estamos hablando de toma de decisión con incertidumbre. El uso de las preferencias ha beneficiado diferentes dominios, como, razonamiento en presencia de información incompleta e incierta, modelado de preferencias de usuario, y toma de decisión con incertidumbre. En la literatura, distintos enfoques simbólicos de razonamiento no clásico han sido creados. Entre ellos, la programación lógica con la semántica de answer set ofrece un buen acercamiento entre representación y procesamiento simbólico del conocimiento, y diferentes extensiones para manejar las preferencias. Sin embargo, en programación lógica se pueden identificar diferentes problemas con respecto al manejo de las preferencias. Por ejemplo, en la mayoría de enfoques de razonamiento no-monótono se asume que las excepciones a default rules de un programa lógico ya están expresadas. Pero, a veces se pueden considerar preferencias implícitas basadas en la especificidad de las reglas para manejar la información incompleta. Además, cuando la información es también incierta, la selección de default rules pueden depender de preferencias explícitas y de la incertidumbre. En el modelado de preferencias, aunque los formalismos existentes basados en programación lógica permitan expresar preferencias que dependen de información contextual e incompleta, in algunas aplicaciones, algunas preferencias en un contexto puede ser más importantes que otras. Por lo tanto, un lenguaje que permita capturar preferencias más complejas es deseable. En la toma de decisiones con incertidumbre, las metodologías basadas en programación lógica creadas hasta ahora no ofrecen una solución del todo satisfactoria al manejo de las preferencias y la incertidumbre. El objectivo de esta tesis es doble: 1) estudiar el rol de las preferencias en programación lógica desde diferentes perspectivas, y 2) contribuir a esta joven área de investigación proponiendo diferentes marcos teóricos y métodos para abordar los problemas anteriormente citados. Para este propósito veremos como las preferencias pueden ser usadas de manera implícita y explícita para la selección de default rules proponiendo: (i) un método para seleccionar reglas en un programa basado en la especificad de las reglas; (ii) un marco teórico para la selección de default rules basado en preferencias explícitas y incertidumbre. También veremos como las preferencias del usuario pueden ser modeladas y procesadas usando un enfoque de programación lógica (iii) para crear un mecanismo de manejo de los perfiles de los usuarios en un sistema con reconocimiento del contexto; (iv) para crear un marco teórico capaz de expresar preferencias con formulas anidadas. Por último, con el objetivo de disminuir la distancia entre programación lógica y la toma de decisión con incertidumbre proponemos (v) una metodología para modelar un problema de toma de decisiones y para inferir una decisión óptima usando un enfoque de programación lógica clásica y uno de programación lógica extendida con lógica posibilística.Sistemi intelligenti, destinati a fornire supporto agli utenti in processi decisionali complessi, richiedono una rappresentazione dell’informazione concisa, formale e che permetta di ragionare in maniera non monotona e incerta. Per poter scegliere tra le diverse opzioni, tali sistemi hanno bisogno di disporre di una rappresentazione del concetto di preferenza altrettanto concisa e formale. Le preferenze offrono una maniera efficace per scegliere le miglior soluzioni di un problema. Tali soluzioni possono rappresentare gli stati del mondo più credibili quando si tratta di ragionamento non monotono, gli stati del mondo più soddisfacenti quando si tratta delle preferenze degli utenti, o le decisioni migliori quando prendiamo una decisione in condizioni di incertezza. Diversi domini come ad esempio il ragionamento non monotono e incerto, la strutturazione del profilo utente, e i modelli di decisione in condizioni d’incertezza hanno tratto beneficio dalla rappresentazione delle preferenze. Nella bibliografia disponibile si possono incontrare diversi approcci simbolici al ragionamento non classico. Tra questi, la programmazione logica con answer set semantics offre un buon compromesso tra rappresentazione simbolica e processamento dell’informazione, e diversi estensioni per la gestione delle preferenze sono state proposti in tal senso. Nonostante ció, nella programmazione logica esistono ancora delle problematiche aperte. Prima di tutto, nella maggior parte degli approcci al ragionamento non monotono, si suppone che nel programma le eccezioni alle regole siano già specificate. Tuttavia, a volte per trattare l’informazione incompleta è possibile prendere in considerazione preferenze implicite basate sulla specificità delle regole. In secondo luogo, la gestione congiunta di eccezioni e incertezza ha avuto scarsa attenzione: quando l’informazione è incerta, la scelta di default rule può essere una questione di preferenze esplicite e d’incertezza allo stesso tempo. Nella creazione di preferenze dell’utente, anche se le specifiche di programmazione logica esistenti permettono di esprimere preferenze che dipendono sia da un’informazione incompleta che da una contestuale, in alcune applicazioni talune preferenze possono essere più importanti di altre, o espressioni più complesse devono essere supportate. In un processo decisionale con incertezza, le metodologie basate sulla programmazione logica viste sinora, non offrono una gestione soddisfacente delle preferenze e dell’incertezza. Lo scopo di questa dissertazione è doppio: 1) chiarire il ruolo che le preferenze giocano nella programmazione logica da diverse prospettive e 2) contribuire proponendo in questo nuovo settore di ricerca, diversi framework e metodi in grado di affrontare le citate problematiche. Per prima cosa, dimostreremo come le preferenze possono essere usate per selezionare default rule in un programma in maniera implicita ed esplicita. In particolare proporremo: (i) un metodo per la selezione delle regole di un programma logico basato sulla specificità dell’informazione; (ii) un framework per la selezione di default rule basato sulle preferenze esplicite e sull’incertezza associata alle regole del programma. Poi, vedremo come le preferenze degli utenti possono essere modellate attraverso un programma logico, (iii) per creare il profilo dell’utente in un sistema context-aware, e (iv) per proporre un framework che supporti la definizione di preferenze complesse. Infine, per colmare le lacune in programmazione logica applicata a un processo di decisione con incertezza (v) proporremo una metodologia basata sulla programmazione logica classica e una metodologia basata su un’estensione della programmazione logica con logica possibilistica

Topics, Presuppositions, and Theticity: An Empirical Study of Verb-Subject Clauses in Albanian, Greek, and Serbo-Croat

Verb-Subject order is often claimed to be the surface expression of thetic utterances, which are supposed to be ontologically different from the classical Aristotelian categoric type: thetic utterances are not divided in two parts (subject and predicate, topic and comment), but represent the information they convey as a cognitive whole. The purpose of the present study is to offer a detailed description of the clauses with this word order in Albanian, Greek, and Serbo-Croat, in which the verb-subject strategy is a very prominent one, and, based on these data, to reexamine the postulates of the theory of two basic utterance types. The results may be subsumed in two claims: (1) The equation "VS = thetic" does not hold true, because subject postponement is a distinctive feature of at least three constructions, which I labeled Inversion, VsX-Construction and vS-Construction. Of these, only the latter resembles what is usually called thetic. (2) The existence of a non-categoric utterance type does not automatically follow from the existence of vS-Construction, since this construction also displays a specific kind of topic-comment articulation, explainable in terms of certain word order and intonation rules of the three languages in question

Topics, presuppositions, and theticity: An empirical study of verb-subject clauses in Albanian, Greek, and Serbo-Croat

LoC Class: PG9522, LoC Subject Headings: Albanian language--Clauses, Greek language/Modern--Clauses, Serbo-Croatian language--Clause

Ethics Inc.: A Sociological Account of the Contemporary Market for Corporate Social Responsibility

In the contemporary corporate marketplace a novel ethical proposal is being formulated. This is manifest in the suggestion that it is desirable for companies to behave in a 'socially responsible' manner, or practice what is formally referred to as 'Corporate Social Responsibility' (CSR). Distinct from conjunctions of 'business' and 'ethics' that have gone before, contemporary CSR proceeds on the basis of a unique claim - that it is possible for a corporation to 'do well, by doing good'. Known as the 'business case' for CSR, this proposal is of special sociological significance, this thesis argues, insofar as it understands 'marketability' to be an inhering aspect of the 'ethical' itself. Drawing on contemporary developments in the field of social studies of science (STS) and, relatedly, 'newer' economic sociology, this thesis attends to the question of what, in-practice and as-practice, this newly described market-ethics may be said to 'do.' This focus on 'doing' distinguishes the present work from prior sociological and economic accounts of the relationship between markets and ethics, which have been noticeably constrained by both historically conferred disciplinary remits and by the tendency to peremptorily prescribe ethics within the narrow bounds of classical deontological or utilitarian moral theories. Methodologically, this inquiry proceeds by first observing the assembly of particular market spheres or market 'nexuses' of CSR practice, and secondly by investigating the ways in which the 'ethical' is variously enacted within these. Three interlinked but delineated 'nexuses' of CSR focus provide empirical substrate for discussion - the 'ethical corporation,' 'ethical consumer,' and 'ethical career.' Paying heed to the multiply-reflexive constitution of these differentially assembled markets, ensuing critical discussion finds the 'doing' of ethics therein to be largely constituent in contingently engaged affective and material practices. Against accounts then that de-cry the increasing 'marketisation' of ever more aspects of everyday life, ( often seeking to indiscriminately discern in all market practice a totalising neo-liberalism on the march), the present thesis embodies an alternative theoretical approach wherein what it is possible to do in a market context is not prescriptively decreed or pre-maturely proscribed. In line with this emphasis, questions regarding the possibility of ethics, and finally, of effective alternative politics in market contexts are reexamined as part of the process of critically rethinking what present sociological understandings admit to and exclude from the designation of 'market' itself

Defining And Displaying Gallo: Language And Ideology In Upper Brittany, France

This dissertation examines discourse practices in and about Gallo, a marginalized Romance language of Upper Brittany, France. Specifically, it explores how various Gallo social actors (advocates, performers, teachers and students) defined, labeled and displayed Gallo, as they constructed it as a language capable of participating in modernity, producing local authority, and forging links with loved people and places. Gallo was popularly imagined as part of a rural past and dismissed as a “deformation” of French, unlike the Breton language, which stood as a salient emblem of Brittany’s cultural distinctiveness. This dissertation elucidates the ideological and everyday consequences of using this ostensibly “traditional” language in “modern” times. Using interactional and ethnographic data collected during twelve months of fieldwork, I investigate how Gallo was represented in multiple contexts: celebratory festivals, association meetings, artistic performances, language classrooms, everyday conversations, and ethnographic interviews. I argue that strategies of Gallo representation involved not just explicit statements about the language but also bids by speakers to assign themselves, as well as interlocutors and/or publics, to participant roles and stances. By occupying these positions, participants jointly articulated language and speakerhood. First, I examine how Gallo was defined as a “language” rather than as deformed French, in promotional materials and performances, and I illustrate how these genres positioned a participant role of Gallo recognizer as desirable and achievable. Second, I explore the implications of patois and gallo as language labels. While Gallo advocates often preferred gallo, I elucidate how even patois allowed speakers to draw useful social distinctions and to meaningfully connect disparate people and places. Thirdly, I discuss how dictionaries, a prominent part of Gallo advocate culture, served as icons of Gallo’s existence and “weight,” indexes of modernity, and triggers for the performance of local expertise. Finally, I show how performers on stage constructed audience members as competent evaluators of Gallo. In sum, this dissertation illustrates that language is both social object and social action. When individuals and institutions propose a representation of a language, they also propose associated participant roles, stances, and figures of speakerhood, which are open to creative recontextualization through interaction and artistic performance