This paper presents an overview of the field of recommender systems and describes the current generation of recommendation methods that are usually classified into the following three main categories: content-based, collaborative, and hybrid recommendation approaches. This paper also describes various limitations of current recommendation methods and discusses possible extensions that can improve recommendation capabilities and make recommender systems applicable to an even broader range of applications. These extensions include, among others, an improvement of understanding of users and items, incorporation of the contextual information into the recommendation process, support for multcriteria ratings, and a provision of more flexible and less intrusive types of recommendations.

Negotiation is essential in settings where autonomous agents have conflicting interests and a desire to cooperate. For this reason, mechanisms in which agents exchange potential agreements according to various rules of interaction have become very popular in recent years as evident, for example, in the auction and mechanism design community. However, a growing body of research is now emerging which points out limitations in such mechanisms and advocates the idea that agents can increase the likelihood and quality of an agreement by exchanging arguments which influence each others ’ states. This community further argues that argument exchange is sometimes essential when various assumptions about agent rationality cannot be satisfied. To this end, in this article, we identify the main research motivations and ambitions behind work in the field. We then provide a conceptual framework through which we outline the core elements and features required by agents engaged in argumentation-based negotiation, as well as the environment that hosts these agents. For each of these elements, we survey and evaluate existing proposed techniques in the literature and highlight the major challenges that need to be addressed if argument-based negotiation research is to reach its full potential.

We propose a dialogue-game protocol of purchase negotiation dialogues which identifies appropriate speech acts, defines constraints on their utterances, and specifies the different sub-tasks agents need to perform in order to engage in dialogues according to this protocol. Our formalism combines a dialogue game from the philosophy of argumentation with a model of rational consumer purchase decision behaviour adopted from marketing theory. In addition to the dialogue formalism, we present a portfolio of decision mechanisms for the participating agents engaged in the dialogue and use these to provide our formalism with an operational semantics.

also grateful for the assistance from the anonymous referees and the associate editor. An Under a revenue-sharing contract, a retailer pays a supplier a wholesale price for each unit purchased plus a percentage of the revenue the retailer generates. Such contracts have become more prevalent in the video cassette rental industry relative to the more conventional wholesale price contract. This paper studies revenue-sharing contracts in a general supply chain model with revenues determined by each retailer’s purchase quantity and price. Demand can be deterministic or stochastic and revenue is generated either from rentals or outright sales. Our model includes the case of a supplier selling to a classical …xed-price newsvendor or a price-setting newsvendor. We demonstrate that revenue sharing coordinates a supply chain with a single retailer (i.e., the retailer chooses optimal price and quantity) and arbitrarily allocates the supply chain’s pro…t. We compare revenue sharing to a number of other supply chain contracts (e.g., buy-back contracts, price-discount contracts,

What distinguishes e-commerce from ordinary commerce? What distinguishes it from distributed computation? In this paper we propose a performative theory of e-commerce, drawing on speech act theory, in which e-commerce exchanges are promises of future commercial actions, whose real-world meanings are constructed jointly and incrementally. We then define a computational model for this theory, called Posit Spaces, along with the syntax and semantics for an agent interaction protocol, the Posit Spaces Protocol or PSP. This protocol enables participants in a multi-agent commercial interaction to propose, accept, modify and revoke joint commitments. Our work integrates three strands of prior research: the theory of Tuple Spaces in distributed computation; formal dialogue games from argumentation theory; and the study of commitments in multi-agent systems.

This paper presents a survey as well as a systematic empirical comparison of seven graph kernels and two related similarity matrices (simply referred to as graph kernels), namely the exponential diffusion kernel, the Laplacian exponential diffusion kernel, the von Neumann diffusion kernel, the regularized Laplacian kernel, the commute-time kernel, the random-walk-with-restart similarity matrix, and finally, three graph kernels introduced in this paper: the regularized commute-time kernel, the Markov diffusion kernel, and the cross-entropy diffusion matrix. The kernel-on-a-graph approach is simple and intuitive. It is illustrated by applying the nine graph kernels to a collaborative-recommendation task and to a semisupervised classification task, both on several databases. The graph methods compute proximity measures between nodes that help study the structure of the graph. Our comparisons suggest that the regularized commute-time and the Markov diffusion kernels perform best, closely followed by the regularized Laplacian kernel. 1

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The simultaneous treatment of two interrelated and well-known tasks from strategic marketing planning, namely the determination of competitive market structure (CMS) and market segmentation, is addressed via application of the "Self-Organizing (Feature) Map" (SOM) methodology, as originally proposed by Kohonen (1982). In the present paper, some major aspects of the methodological basis of the SOM method are outlined and an SOM-based joint CMS-(preference-)segmentation analysis is illustrated using individual brand choice probabilities derived from diary household panel data. 1. Introduction The analysis of competitive market structure (CMS) represents an important concept in the (strategic) marketing planning process (see, e.g., Wind and Robertson, 1983; Day, 1984; Myers, 1996). In an excellent exposition of contemporary approaches to the determination of CMS, DeSarbo, Manrai and Manrai (1993) describe the primary task of CMS analysis as deriving a configuration of products/brands in...

CONTENTS 1. Introduction 2. Practical Reasoning 3. Argument Schemes and Defeasibility 4. Decision Calculi 5. Reasoning under Resource Constraints 6. Moral Considerations 7. Deliberation Dialogue 8. Interface Design 9. Evaluation 10. Summary Group 2 2 Practical Reasoning 1 Introduction When faced with difficult decisions about what to do, decision makers benefit from good advice. Good advice comes most reliably from advisors with relevant expertise. As well, good advice has at least three other essential features. First, the advice should be presented in a form which can be readily understood by the decision maker. Second, there should be ready access to both the information and the thinking that underpins the advice. Third, if decision making involves details which are at all unusual, the decision maker needs to be able to discuss those details with their advisors. Computer based systems are being increasingly used to assist people in decision making. Su

This paper takes the first steps towards a generic theory of strategy in negotiation interactions between autonomous computational agents. Previous efforts at defining and studying negotiation strategies have done so within the context of a particular interaction protocol, or class of protocols. In order to develop a protocol-independent theory of strategy, we first identify the factors which may influence the creation of a strategy for a rational agent, and then consider some of these in more detail. As an example, we apply our generic approach to the Zeuthen strategy of the Monotonic Concession Protocol and a particular strategy from the International