Luís Manuel Pereira

These are the proceedings of the First International Conference on Compu- tional Logic (CL 2000) which was held at Imperial College in London from 24th to 28th July, 2000. The theme of the conference covered all aspects of the theory, implementation, and application of computational logic, where computational logic is to be understood broadly as the use of logic in computer science. The conference was collocated with the following events: { 6th International Conference on Rules and Objects in Databases (DOOD 2000) { 10th International Workshop on Logic-based Program Synthesis and Tra- formation (LOPSTR 2000) { 10th International Conference on Inductive Logic Programming (ILP 2000). CL 2000 consisted of seven streams: { Program Development (LOPSTR 2000) { Logic Programming: Theory and Extensions { Constraints { Automated Deduction: Putting Theory into Practice { Knowledge Representation and Non-monotonic Reasoning { Database Systems (DOOD 2000) { Logic Programming: Implementations and Applications. The LOPSTR 2000 workshop constituted the program development stream and the DOOD 2000 conference constituted the database systems stream. Each stream had its own chair and program committee, which autonomously selected the papers in the area of the stream. Overall, 176 papers were submitted, of which 86 were selected to be presented at the conference and appear in these proceedings. The acceptance rate was uniform across the streams. In addition, LOPSTR 2000 accepted about 15 extended abstracts to be presented at the conference in the program development stream.

O presente trabalho teve como objetivo avaliar o efeito da terminação de cordeiros confinados usando resíduo úmido de cervejaria como fonte de volumoso ofertado em diferentes frequências de alimentação sobre as características da carcaça e não componentes da carcaça. Foram utilizados 30 cordeiros machos não castrados, oriundos de um cruzamento alternado entre as raças Texel e Ile de France. Os animais apresentaram ao início do confinamento idade média de 72,7±6 dias e peso médio de 25,44±4,1 kg. Os tratamentos eram constituídos de três diferentes frequências de alimentação, sendo: uma vez ao dia (08:00 horas), duas vezes ao dia (08:00 e 18:00 horas) e três vezes ao dia (08:00, 13:00 e 18:00 horas). A relação volumoso:concentrado usada foi de 46,9:53,1 com base na matéria seca. Os cordeiros foram abatidos quando atingiram o peso vivo de fazenda, de 38 kg. Houve diferença estatística (P<0,05) para as variáveis peso e rendimento de costelas, peso e proporção de Rins e peso de Rum+Ret. As demais variáveis não diferiram (P>0,05) entre os tratamentos. Em função dos resultados podemos recomendar uma única oferta diária como manejo alimentar para cordeiros terminados em confinamento recebendo resíduo úmido de cervejaria como fonte de volumoso. Palavras-chave: Cordeiro, Carcaça, Resíduo de Cervejaria, Confinamento. ABSTRACT The present work aimed to evaluate the effect of finishing confined lambs using wet brewery residue as a source of roughage offered at different feeding frequencies on the characteristics of the carcass and non-carcass components. 30 uncastrated male lambs were used, coming from an alternating cross between the Texel and Ile de France breeds. At the beginning of confinement, the animals had an average age of 72.7±6 days and an average weight of 25.44±4.1 kg. The treatments consisted of three different feeding frequencies: once a day (08:00), twice a day (08:00 and 18:00) and three times a day (08:00, 13:00). 00 and 18:00 hours). The roughage:concentrate ratio used was 46.9:53.1 based on dry matter. Lambs were slaughtered when they reached farm live weight of 38 kg. There was a statistical difference (P<0.05) for the variables weight and yield of ribs, weight and proportion of Kidneys and weight of Rum+Ret. The other variables did not differ (P>0.05) between treatments. Based on the results, we can recommend a single daily supply as a dietary management for lambs finished in confinement receiving wet brewery residue as a source of roughage. Keywords: Lambs, Carcass, Brewery Residue, Confinement. RESUMEN El presente trabajo tuvo como objetivo evaluar el efecto del acabado de corderos confinados utilizando residuos húmedos de cervecería como fuente de forraje ofrecido en diferentes frecuencias de alimentación sobre las características de los componentes de la carcasa y no carcasa. Se utilizaron 30 corderos machos sin castrar, procedentes de un cruce alterno entre las razas Texel e Ile de France. Al inicio del confinamiento, los animales tenían una edad promedio de 72,7±6 días y un peso promedio de 25,44±4,1 kg. Los tratamientos consistieron en tres frecuencias de alimentación diferentes: una vez al día (08:00), dos veces al día (08:00 y 18:00) y tres veces al día (08:00, 13:00 y 18:00). horas). La relación forraje:concentrado utilizada fue 46,9:53,1 basada en materia seca. Los corderos fueron sacrificados cuando alcanzaron un peso vivo en granja de 38 kg. Hubo diferencia estadística (P<0,05) para las variables peso y rendimiento de costillas, peso y proporción de Riñones y peso de Ron+Ret. Las demás variables no difirieron (P>0.05) entre tratamientos. Con base en los resultados, podemos recomendar un suministro único diario como manejo dietético para corderos terminados en confinamiento que reciben residuos húmedos de cervecería como fuente de forraje. Palabras clave: Cordero, Carcasa, Residuos de Cervecería, Confinamiento.

Counterfactual Thinking is a human cognitive ability studied in a wide variety of domains. It captures the process of reasoning about a past event that did not occur, namely what would have happened had this event occurred, or, otherwise, to reason about an event that did occur but what would ensue had it not. Given the wide cognitive empowerment of counterfactual reasoning in the human individual, the question arises of how the presence of individuals with this capability may improve cooperation in populations of self-regarding individuals. Here we propose a mathematical model, grounded on Evolutionary Game Theory, to examine the population dynamics emerging from the interplay between counterfactual thinking and social learning (i.e., individuals that learn from the actions and success of others) whenever the individuals in the population face a collective dilemma. Our results suggest that counterfactual reasoning fosters coordination in collective action problems occurring in large populations, and has a limited impact on cooperation dilemmas in which coordination is not required. Moreover, we show that a small prevalence of individuals resorting to counterfactual thinking is enough to nudge an entire population towards highly cooperative standards.

Counterfactuals are conjectures about what would have happened, had an alternative event occurred. It provides lessons for the future by virtue of contemplating alternatives; it permits thought debugging; it supports a justification why different alternatives would have been worse or not better. Typical expressions are: “If only I were taller …”, “I could have been a winner …”, “I would have passed, were it not for …”, “Even if... the same would follow”. Counterfactuals have been well studied in Linguistics, Philosophy, Physics, Ethics, Psychology, Anthropology, and Computation, but not much within Critical Thinking. The purpose of this study is to illustrate counterfactual thinking, through logic program abduction and updating, and inspired by Pearl’s structural theory of counterfactuals, with an original application to morality, a common concern for critical thinking. In summary, we show counterfactual reasoning to be quite useful for critical thinking, namely about moral issues.

This book constitutes the refereed proceedings of the European Workshop on Logics in Artificial Intelligence, JELIA 2000, held in Malaga, Spain in September/October 2000. The 24 revised full papers presented together with three invited papers were carefully reviewed and selected out of 60 submissions. The papers are organized in topical sections on knowledge representation, reasoning about actions, belief revision, theorem proving, argumentation, agents, decidability and complexity, updates, and preferences.

This book discusses the two realms of machine ethics, a field that is now becoming a pressing concern and receiving wide attention due to its growing importance. It makes a number of original inroads that exhibit a proof of possibility to systematically represent and reason about a variety of issues from the chosen moral facets by means of moral examples taken off-the-shelf from the morality literature. Given the broad dimension of the topic, the contributions in the book touch solely on a dearth of morality issues. Nevertheless, it prepares and opens the way for additional research towards employing various features available in LP-based reasoning and EGT to machine ethics. Moreover, we draw attention to some salient philosophical considerations underpinning and surging from our work.

In this chapter, a survey of research in machine ethics is presented, providing the context and the motivation for our investigations. The survey concerns the individual realm of machine ethics, whereas the background to other realm, the collective one, is broached in Chap. 9, namely Sects. 9.1 and 9.2.1. The first realm views computation as a vehicle for representing moral cognition of an agent and its reasoning thereof, which motivates our investigation for employing Logic Programming (LP) knowledge representation and reasoning features with respect to the individual realm of machine ethics. On the other hand, the second realm emphasizes the emergence, in a population, of evolutionarily stable moral norms, of fair and just cooperation, that ably discards free riders and deceivers, to the advantage of the whole evolved population. It provides a motivation of our research for introducing cognitive abilities, such as intention recognition, commitment, revenge, apology, and forgiveness, to reinforce the emergence of cooperation in the collective realm of machine ethics.

This chapter provides necessary background of Logic Programming (LP) used throughout this book, including semantics of Logic Programs (particularly the Stable Model and the Well-Founded Semantics). The subsequent part of this chapter briefly overview considered LP reasoning features: abduction, preferences, probabilistic LP, updating, LP counterfactuals, and tabling. Moreover, the appropriateness of these features for representing and reasoning about diverse issues of moral facets tackled in this book is discussed.

This chapter addresses the collective realm computationally, using Evolutionary Game Theory in populations of individuals, to report on norms and morality emergence. These populations, to start with, are not equipped with much cognitive capability, and simply act from a predetermined set of actions. Our research has shown that the introduction of cognitive capabilities, such as intention recognition, commitment, apology, forgiveness, and revenge, separately and jointly, reinforce the emergence of cooperation in populations, comparatively to their absence. We then prospect future work concerned with adding guilt.

This chapter reports on our literature study in moral philosophy and psychology for choosing conceptual viewpoints close to LP-based reasoning. These viewpoints fall into three moral facets tackled in this book. First, we study moral permissibility, taking into account the Doctrines of Double Effect, Triple Effect, and Scanlonian contractualism. Second, we look into the dual-process model that stresses the interaction between deliberative and reactive processes in delivering moral decisions. Finally, we discuss the role of counterfactual thinking in moral reasoning.

Counterfactuals capture the process of reasoning about a past event that did not occur, namely what would have happened had this event occurred; or, vice-versa, to reason about an event that did occur but what if it had not. In this chapter, we innovatively make use of LP abduction and updating in an implemented procedure for evaluating counterfactuals, taking the established structural approach of Pearl as reference. Our approach concentrates on pure non-probabilistic counterfactual reasoning in LP, resorting to abduction and updating, in order to determine the logical validity of counterfactuals under the Well-Founded Semantics. Nevertheless, the approach is adaptable to other semantics, too. Even though the LP technique introduced in this chapter is relevant for modeling counterfactual moral reasoning, its use is general, not specific to morality.

In the individual realm part of this book, we are addressing the interplay amongst appropriate LP features to represent moral facets and to reason about them. One such interplay is between LP abduction and updating, both supported with tabling mechanisms. In this chapter, we propose novel approaches for employing tabling in abduction and updating—separately—viz., tabling abductive solutions in contextual abduction and the incremental tabling of fluents for LP updating. These two individual approaches form the components for their subsequent joint tabling technique when combining LP abduction and updating, to be discussed in detail in Chap. 7. The new techniques introduced here, as well as their later joint combination, are general for normal logic programs, and not specific to morality applications. That is, they are of interest in themselves and may be applicable to other domains.