Inference-Guiding for Intelligent Agents

In many applications of intelligent agents, initially given facts are not sufficient to reach a decision, and more data are needed. In that case. Inference-guiding is needed to identify the missing information and lead inference to a conclusion. This paper presents a new inferenceguiding strategy that selects the key pieces of missing information in such a way that the total cost of acquiring additional information for reaching a conclusion is the lowest. The computational experiments show that the new strategy is more effective and economical than the inference-guiding strategies currently available for the intelligent systems

Abductive Equivalential Translation and its application to Natural Language Database Interfacing

The thesis describes a logical formalization of natural-language database interfacing. We assume the existence of a ``natural language engine'' capable of mediating between surface linguistic string and their representations as ``literal'' logical forms: the focus of interest will be the question of relating ``literal'' logical forms to representations in terms of primitives meaningful to the underlying database engine. We begin by describing the nature of the problem, and show how a variety of interface functionalities can be considered as instances of a type of formal inference task which we call ``Abductive Equivalential Translation'' (AET); functionalities which can be reduced to this form include answering questions, responding to commands, reasoning about the completeness of answers, answering meta-questions of type ``Do you know...'', and generating assertions and questions. In each case, a ``linguistic domain theory'' (LDT) $\Gamma$ and an input formula $F$ are given, and the goal is to construct a formula with certain properties which is equivalent to $F$, given $\Gamma$ and a set of permitted assumptions. If the LDT is of a certain specified type, whose formulas are either conditional equivalences or Horn-clauses, we show that the AET problem can be reduced to a goal-directed inference method. We present an abstract description of this method, and sketch its realization in Prolog. The relationship between AET and several problems previously discussed in the literature is discussed. In particular, we show how AET can provide a simple and elegant solution to the so-called ``Doctor on Board'' problem, and in effect allows a ``relativization'' of the Closed World Assumption. The ideas in the thesis have all been implemented concretely within the SRI CLARE project, using a real projects and payments database. The LDT for the example database is described in detail, and examples of the types of functionality that can be achieved within the example domain are presented.Comment: 162 pages, Latex source, PhD thesis (U Stockholm, 1993). Uses style-file ustockholm_thesis.st

Inference-Guiding on Bayesian Knowledge-Based Systems

Bayesian network is a robust structure for representing knowledge containing uncertainties in a knowledge-based system. In applications of expert systems and knowledge-based systems, it often happens that initial data are not sufficient to derive a conclusion of high enough certainty. Inference-guiding is in that case to identify the missing information, pursue its value, and lead inference to a conclusion. This paper presents and characterizes a criterion for effectively selecting key missing information, and thereby develops a “smart” inference approach with the inference-guiding function based on the newly developed criterion for uncertain inference in a Bayesian knowledge-based system

Fault detection and rectification algorithms in a question-answering system

A Malay proverb "jika sesat di hujung jalan, baleklah kepangkal jalan" roughly means "if you get lost at the end of the road, go back to the beginning". In going back to the beginning of the road, we learn our mistakes and hopefully will not repeat the same mistake again. Thus, this work investigates the use of formal logic as a practical tool for reasoning why we could not infer or deduce a correct answer from a question posed to a database. An extension of the Prolog interpreter is written to mechanise a theorem-proving system based on Horn clauses. This extension procedure will form the basis of the question-answering system. Both input into and output from this system is in the form of predicate calculus. This system can answer all four classes of questions as classified by Chang and Lee (1973). [Continues.

Investigations into Satisfiability Search

In this dissertation we investigate theoretical aspects of some practical approaches used in solving and understanding search problems. We concentrate on the Satisfiability problem, which is a strong representative from search problem domains. The work develops general theoretical foundations to investigate some practical aspects of satisfiability search. This results in a better understanding of the fundamental mechanics for search algorithm construction and behaviour. A theory of choice or branching heuristics is presented, accompanied by results showing a correspondence of both parameterisations and performance when the method is compared to previous empirically motivated branching techniques. The logical foundations of the backtracking mechanism are explored alongside formulations for reasoning in relevant logics which results in the development of a malleable backtracking mechanism that subsumes other intelligent backtracking proof construction techniques and allows the incorporation of proof rearrangement strategies. Moreover, empirical tests show that relevant backtracking outperforms all other forms of intelligent backtracking search tree construction methods. An investigation into modelling and generating world problem instances justifies a modularised problem model proposal which is used experimentally to highlight the practicability of search algorithms for the proposed model and related domains

Integrating bottom-up and top-down reasoning in COLAB

The knowledge compilation laboratory COLAB integrates declarative knowledge representation formalisms, providing source-to-source and source-to-code compilers of various knowledge types. Its architecture separates taxonomical and assertional knowledge. The assertional component consists of a constraint system and a rule system, which supports bottom-up and top-down reasoning of Horn clauses. Two approaches for forward reasoning have been implemented. The first set-oriented approach uses a fixpoint computation. It allows top-down verification of selected premises. Goal-directed bottom-up reasoning is achieved by a magic-set transformation of the rules with respect to a goal. The second tuple-oriented approach reasons forward to derive the consequences of an explicitly given set of facts. This is achieved by a transformation of the rules to top-down executable Horn clauses. The paper gives an overview of the various forward reasoning approaches, their compilation into an abstract machine and their integration into the COLAB shell

Labor Standards and Human Rights: Implications for International Trade and Investment

The establishment of international labor standards linked to market access within the WTO is among the proposals intended to remedy the gross violations of labor and human rights that accompany international trade and investment. Yet, the WTO Charter and, previously, the GATT are virtually silent on the potential inhumanity of globally integrated goods and services markets. Despite intense pressure from the United States and the European Union, the Singapore Ministerial Declaration (December 1996), while acknowledging the importance of international labor standards, identified the International Labor Organization (ILO) as the competent body to establish and monitor labor standards. However, advocates for international labor standards ultimately gained access to the process of rules-setting in the WTO indirectly through Article XXIV governing the creation of customs unions and free trade agreements and, more importantly, the 1971 GSP Decision permitting special and differential treatment of developing country exports. Thus, contrary to the WTO Ministerial dictates, labor standards are now routinely enforced by the prospective loss of preferential tariff concessions and market access. We discuss in this context a mechanism for linking ILO-established labor standards, monitoring by the ILO, and enforcement through the threat of lost trade concessions that emerged fully operational in the 1999 U.S.-Cambodia Bilateral Textile Trade Agreement. Under this agreement, the United States provided Cambodia access to US markets by giving expanded apparel and textile quotas conditional on improved working conditions in the garment sector. We also discuss the labor and human-rights issues that emerge in a globalizing world economy, the market failures that produce labor and human-rights violations, and the role of labor standards in mitigating the most grievous of consequences. We then discuss the evidence on the impact that labor standards have on trade, firm behavior and investment, and on workers, and whether or not there is a race to the bottom, which we conclude not to be the case.International Labor Standards; ILO; WTO; Effects on Trade and Investment

Patent Pool Outsiders

Individuals who decline to join cooperative groups — outsiders — raise concerns in many areas of law and policy. From trade policy to climate agreements to class action procedures, the fundamental concern is the same: a single member of the group who drops out could weaken the remaining union. This Article analyzes the outsider problem as it affects patents. The outsider question has important bearing on patent and antitrust policy. By centralizing and simplifying complex patent licensing deals, patent pools conserve tremendous transaction costs. This allows for the widespread production and competitive sale of many useful technologies, particularly in the consumer electronics industry. Because these transaction cost savings appear to outweigh the most common competition-related concerns patent pools raise, antitrust authorities generally view these private pools favorably. Others are less sanguine. Most patent pools are incomplete: for the technologies they cover, not all relevant patents are included. The reason for this is understandable: patent holders sometimes believe they can negotiate for higher royalties by declining to join an existing pool. Antitrust regulators are aware of this behavior, but do not worry much about it. A growing number of economists and legal scholars believe, however, that this outsider behavior may impose higher costs on pool licensees, detracting from the central benefit that patent pools offer — transaction cost savings. These commentators urge antitrust regulators to regard patent pools with greater caution and skepticism. These calls for caution, however, are based mostly on theories about how patent pools should work, rather than empirical study. Remarkably, little research has been done to shed light on the actual impact of patent pool outsiders. Through an original ethnographic study, this Article seeks to remedy this gap. A set of the most notable and public episodes of outsider behavior were collected from industry press reports, case reports, and historical archives. Crucial new information was then gathered through interviews with lawyers and executives directly involved with the episodes studied. The study reveals a characteristic of patent pools that has gone unappreciated until now: they subtly but powerfully influence bargains that take place “poolside” — i.e., deals between patent holders and licensees that take place “in the shadow” of the pool. This spill-over effect can beneficially limit the power that theorists have assumed outsiders to have. This is an unappreciated benefit of cooperation. The theorists, as it turns out, have not used the wrong approach, but rather, have been missing some important parameters. To further aid regulators, this Article builds upon its qualitative findings by introducing a new quantitative technique for estimating the cost that a licensee either incurs or saves due to an outsider. Applying this technique to original financial and industry data gathered from research subjects, this Article shows that, counterintuitively, patent licensees are sometimes better-off where cooperation among licensors is partial, rather than complete. The inflection point lies where the royalty rate hike that a unified pool would need to charge to draw in an outsider is equal to the transaction costs that licensees would conserve by dealing with a single pool. This study’s revelations have provocative implications that reach beyond patent law. Contrary to conventional wisdom, slightly fragmented property markets may sometimes be preferable to “grand coalitions.” There may exist in any given market for complementary patent rights (or other complementary property rights), an optimal level of diffusion of ownership that resides between total diffusion and total concentration. Some cooperation may not only be better than none, but also better than more. Drawing upon this study, antitrust regulators who must evaluate patent pools can assemble a clearer and more complete understanding of their overall costs and benefits — a topic that Robert Merges and I recently wrote on in a related article. This Article is also helpful beyond patent law. The ethnographic methodology followed here reveals dynamics between outsiders and groups that theory alone has not captured. Scholars concerned with outsiders in other areas of law and policy can refine and build upon theory by applying a similar ethnographic approach

A Fair Trial: When the Constitution Requires Attorneys to Investigate Their Clients\u27 Brains

The U.S. Constitution guarantees every criminal defendant the right to a fair trial. This fundamental right includes the right to a defense counsel who provides effective assistance. To be effective, attorneys must sometimes develop specific types of evidence in crafting the best defense. In recent years, the U.S. Supreme Court has found that defense attorneys did not provide effective assistance when they failed to consider neuroscience. But when must defense attorneys develop neuroscience in order to provide effective assistance? This question is difficult because the standard for determining effective assistance is still evolving. There are two leading approaches. First, in Strickland v. Washington, the Court adopted a two-prong “reasonableness” test, which, according to Justice O’Conner, may result in court decisions that fail to properly protect a criminal defendant’s rights. Recently, courts have adopted a second approach based on guidelines promulgated by the American Bar Association. This Note aims to answer this question. It first provides a background on the right to effective assistance of counsel and briefly describes neuroscience evidence, oppositions to and limitations on in its use, and its admissibility in court. Second, this Note attempts to give some guidance to attorneys by exploring the American Bar Association and U.S. Supreme Court standards. Third, it summarizes the results of a statistical analysis conducted by the author, which helps further define when courts require attorneys to develop neuroscience evidence. It concludes by arguing that attorneys need guidance to ensure they are not violating the Sixth Amendment. This Note expands on the American Bar Association’s standard and suggests a framework attorneys may use to determine whether they should develop neuroscience evidence to ensure that their client has a fair trial