Borrajo, Daniel
Domain-independent generation and classification of behavior traces
Borrajo, Daniel, Veloso, Manuela
Financial institutions mostly deal with people. Therefore, characterizing different kinds of human behavior can greatly help institutions for improving their relation with customers and with regulatory offices. In many of such interactions, humans have some internal goals, and execute some actions within the financial system that lead them to achieve their goals. In this paper, we tackle these tasks as a behavior-traces classification task. An observer agent tries to learn characterizing other agents by observing their behavior when taking actions in a given environment. The other agents can be of several types and the goal of the observer is to identify the type of the other agent given a trace of observations. We present CABBOT, a learning technique that allows the agent to perform on-line classification of the type of planning agent whose behavior is observing. In this work, the observer agent has partial and noisy observability of the environment (state and actions of the other agents). In order to evaluate the performance of the learning technique, we have generated a domain-independent goal-based simulator of agents. We present experiments in several (both financial and non-financial) domains with promising results.
Simulating and classifying behavior in adversarial environments based on action-state traces: an application to money laundering
Borrajo, Daniel, Veloso, Manuela, Shah, Sameena
Many business applications involve adversarial relationships in which both sides adapt their strategies to optimize their opposing benefits. One of the key characteristics of these applications is the wide range of strategies that an adversary may choose as they adapt their strategy dynamically to sustain benefits and evade authorities. In this paper, we present a novel way of approaching these types of applications, in particular in the context of Anti-Money Laundering. We provide a mechanism through which diverse, realistic and new unobserved behavior may be generated to discover potential unobserved adversarial actions to enable organizations to preemptively mitigate these risks. In this regard, we make three main contributions. (a) Propose a novel behavior-based model as opposed to individual transactions-based models currently used by financial institutions. We introduce behavior traces as enriched relational representation to represent observed human behavior. (b) A modelling approach that observes these traces and is able to accurately infer the goals of actors by classifying the behavior into money laundering or standard behavior despite significant unobserved activity. And (c) a synthetic behavior simulator that can generate new previously unseen traces. The simulator incorporates a high level of flexibility in the behavioral parameters so that we can challenge the detection algorithm. Finally, we provide experimental results that show that the learning module (automated investigator) that has only partial observability can still successfully infer the type of behavior, and thus the simulated goals, followed by customers based on traces - a key aspiration for many applications today.
Guarantees for Sound Abstractions for Generalized Planning (Extended Paper)
Bonet, Blai, Fuentetaja, Raquel, E-Martin, Yolanda, Borrajo, Daniel
Generalized planning is about finding plans that solve collections of planning instances, often infinite collections, rather than single instances. Recently it has been shown how to reduce the planning problem for generalized planning to the planning problem for a qualitative numerical problem; the latter being a reformulation that simultaneously captures all the instances in the collection. An important thread of research thus consists in finding such reformulations, or abstractions, automatically. A recent proposal learns the abstractions inductively from a finite and small sample of transitions from instances in the collection. However, as in all inductive processes, the learned abstraction is not guaranteed to be correct for the whole collection. In this work we address this limitation by performing an analysis of the abstraction with respect to the collection, and show how to obtain formal guarantees for generalization. These guarantees, in the form of first-order formulas, may be used to 1) define subcollections of instances on which the abstraction is guaranteed to be sound, 2) obtain necessary conditions for generalization under certain assumptions, and 3) do automated synthesis of complex invariants for planning problems. Our framework is general, it can be extended or combined with other approaches, and it has applications that go beyond generalized planning.
Error Analysis and Correction for Weighted A*'s Suboptimality (Extended Version)
Holte, Robert C., Majadas, Ruben, Pozanco, Alberto, Borrajo, Daniel
Weighted A* (wA*) is a widely used algorithm for rapidly, but suboptimally, solving planning and search problems. The cost of the solution it produces is guaranteed to be at most W times the optimal solution cost, where W is the weight wA* uses in prioritizing open nodes. W is therefore a suboptimality bound for the solution produced by wA*. There is broad consensus that this bound is not very accurate, that the actual suboptimality of wA*'s solution is often much less than W times optimal. However, there is very little published evidence supporting that view, and no existing explanation of why W is a poor bound. This paper fills in these gaps in the literature. We begin with a large-scale experiment demonstrating that, across a wide variety of domains and heuristics for those domains, W is indeed very often far from the true suboptimality of wA*'s solution. We then analytically identify the potential sources of error. Finally, we present a practical method for correcting for two of these sources of error and experimentally show that the correction frequently eliminates much of the error.
Meta-Search Through the Space of Representations and Heuristics on a Problem by Problem Basis
Fuentetaja, Raquel (Universidad Carlos III de Madrid) | Barley, Michael (University of Auckland) | Borrajo, Daniel (Universidad Carlos III de Madrid) | Douglas, Jordan (University of Auckland) | Franco, Santiago (University of Huddersfield) | Riddle, Patricia (University of Auckland)
Two key aspects of problem solving are representation and search heuristics. Both theoretical and experimental studies have shown that there is no one best problem representation nor one best search heuristic. Therefore, some recent methods, e.g., portfolios, learn a good combination of problem solvers to be used in a given domain or set of domains. There are even dynamic portfolios that select a particular combination of problem solvers specific to a problem. These approaches: (1) need to perform a learning step; (2) do not usually focus on changing the representation of the input domain/problem; and (3) frequently do not adapt the portfolio to the specific problem. This paper describes a meta-reasoning system that searches through the space of combinations of representations and heuristics to find one suitable for optimally solving the specific problem. We show that this approach can be better than selecting a combination to use for all problems within a domain and is competitive with state of the art optimal planners.
Flexible Integration of Planning and Information Gathering
Camacho, David (Universidad Autonoma de Madrid) | Borrajo, Daniel (Universidad Autonoma de Madrid) | Molina, José M. (Universidad Autonoma de Madrid) | Aler, Ricardo (Universidad Autonoma de Madrid)
The evolution of the electronic sources connected through wide area networks like Internet has encouraged the development of new information gathering techniques that go beyond traditional information retrieval and WEB search methods. They use advanced techniques, like planning or constraint programming, to integrate and reason about hetereogeneous information sources. In this paper we describe MAPWEB. MAPWEB is a multiagent framework that integrates planning agents and WEB information retrieval agents. The goal of this framework is to deal with problems that require planning with information to be gathered from the WEB. MAPWEB decouples planning from information gathering, by splitting a planning problem into two parts: solving an abstract problem and validating and completing the abstract solutions by means of information gathering. This decoupling allows also to address an important aspect of information gathering: the WEB is a dynamic medium and more and more companies make their information available in the WEB everyday. The MAPWEB framework can be adapted quickly to these changes by just modifying the planning domain and adding the required information gathering agents. For instance, in a travel assistant domain, if taxi companies begin to offer WEB information, it would only be necessary to add new planning operators related to traveling by taxi, for a more complete travel domain. This paper describes the MAPWEB planning process, focusing on the aforementioned flexibility aspect.
Preface
Cesta, Amedeo (CNR - National Research Council of Italy) | Borrajo, Daniel (Universidad Carlos III de Madrid)
This volume contains the papers accepted for presentation at ECP 2001, the Sixth European Conference on Planning, held in Toledo, Spain, on September 12-14, 2001. ECP continued the traditional high standards of AIPS and ECP as an archival forum for new research in the field of automated planning and scheduling. ECP conferences were first organized in 1991.
OnDroad Planner: Building Tourist Plans Using Traveling Social Network Information
Cenamor, Isabel (Universidad Carlos III de Madrid) | Rosa, Tomás de la (Universidad Carlos III de Madrid) | Borrajo, Daniel (Universidad Carlos III de Madrid)
One of the key challenges in automated planning is to define the sources of information that will feed the initial state and goals of each planning task. In many domains, the information comes from company's databases. In other applications, the information is harder to obtain and it is usually partial. In this paper, we will describe an application on travel planning, where the initial state and goals will be obtained by crowdsourcing. Travel planning requires the use of plenty Internet-based resources; some of them are related to human generated opinions on all kinds of matters (e.g. hotels, places to visit, restaurants, ...). We present the OnDroad planner, a system that creates personalized tourist plans using the human generated information gathered from the minube traveling social network. OnDroad proposes an initial tourist guide according to the recommendation of the users profiles and their contacts. In addition, this guide can be continuously updated with newly generated data.
Autonomous Mobile Robot Control and Learning with the PELEA Architecture
Quintero, Ezequiel (Universidad Carlos III de Madrid) | Alcázar, Vidal (Universidad Carlos III de Madrid) | Borrajo, Daniel (Universidad Carlos III de Madrid) | Fdez-Olivares, Juan (Universidad de Granada) | Fernández, Fernando (Universidad Carlos III de Madrid) | García-Olaya, Ángel (Universidad Carlos III de Madrid) | Guzmán, César (Universidad Politecnica de Valencia) | Onaindía, Eva (Universidad Politecnica de Valencia) | Prior, David (Universidad de Granada)
In this paper we describe the integration of a robot control platform (Player/Stage) and a real robot (Pioneer P3DX) with PELEA (Planning, Execution and LEarning Architecture). PELEA is a general-purpose planning architecture suitable for a wide range of real world applications, from robotics to emergency management. It allows planning engineers to generate planning applications since it integrates planning, execution, replanning, monitoring and learning capabilities. We also present a relational learning approach for automatically modeling robot-action execution durations, with the purpose of improving the planning process of PELEA by refining domain definitions.
Knowledge Transfer between Automated Planners
Fernandez, Susana (Universidad Carlos III de Madrid) | Aler, Ricardo (Universidad Carlos III de Madrid) | Borrajo, Daniel (Universidad Carlos III de Madrid)
In this article, we discuss the problem of transferring search heuristics from one planner to another. More specifically, we demonstrate how to transfer the domain-dependent heuristics acquired by one planner into a second planner. Our motivation is to improve the efficiency and the efficacy of the second planner by allowing it to use the transferred heuristics to capture domain regularities that it would not otherwise recognize. Our experimental results show that the transferred knowledge does improve the second planner's performance on novel tasks over a set of seven benchmark planning domains.