Laura Sebastia

Universitat Politècnica de València | UPV · Department of Computer Systems and Computation

Landmarks are one of the most effective search heuristics for classical planning, but largely ignored in generalized planning. Generalized planning (GP) is usually addressed as a combinatorial search in a given space of algorithmic solutions, where candidate solutions are evaluated w.r.t. the instances they solve. This type of solution evaluation i...

Landmarks are one of the most effective search heuristics for classical planning, but largely ignored in generalized planning. Generalized planning (GP) is usually addressed as a combinatorial search in a given space of algorithmic solutions, where candidate solutions are evaluated w.r.t.~the instances they solve. This type of solution evaluation i...

Data are the fundamental building blocks to conduct scientific studies that seek to understand natural phenomena in space and time. The notion of data processing is ubiquitous and nearly operates in any project that requires gaining insight from the data. The increasing availability of information sources, data formats and download services offered...

Since 2007, the World Economic Forum (WEF) has issued data on the factors and policies that contribute to the development of tourism and competitiveness across countries worldwide. While WEF compiles the yearly report out of data from governmental and private stakeholders, we seek to analyze the representativeness of the open and collaborative plat...

Integrating collaborative data in data-driven Business Intelligence (BI) system brings an opportunity to foster the decision-making process towards improving tourism competitiveness. This article presents BITOUR, a BI platform that integrates four collaborative data sources (Twitter, Openstreetmap, Tripadvisor and Airbnb). BITOUR follows a classica...

Research on AI is more and more focusing towards explainable technology that accounts for the outcomes of programs and products. One important aspect in this direction is the ability to recognize the behaviour patterns of our application in order to make sensible and informed decisions. In this work, we aim to uncover the behaviour of a planning ag...

Many tourist applications provide personalized tourist tours which take into account the preferences defined by the user interests and also the constraints derived from location of places to visit, opening hours, time availability, etc. Although user preferences are usually related to the category of the points of interest, a user may also have pre...

Biometeorology is the field that relates meteorological and climatic variables with humans, animals and the environment in order to be studied jointly with their geographical distribution. The wide variety of data sources and the highly specialised data formats are fundamental issues for users in this area. This paper presents some preliminary resu...

Promoting a tourist destination requires uncovering travel patterns and destination choices, identifying the profile of visitors and analyzing attitudes and preferences of visitors for the city. To this end, tourism-related data are an invaluable asset to understand tourism behaviour, obtain statistical records and support decision-making for busin...

Nowadays, recommender systems are present in many daily activities such as online shopping, browsing social networks, etc. Given the rising demand for reinvigoration of the tourist industry through information technology, recommenders have been included into tourism websites such as Expedia, Booking or Tripadvisor, among others. Furthermore, the am...

Nowadays, social networks are daily used to share what people like, feel, where they travel to, etc. This huge amount of data can say a lot about their personality because it may reect their behaviour from the “real world” to the “virtual world”. Once obtained the access to this data, some authors have tried to infer the personality of the individu...

In recent years, an evolution of recommendation systems has been observed. New advisory systems have been gaining space, using new tools, algorithms and recommending techniques, not only to increase accuracy, but also to positively surprise the user, that is, to provide serendipitous recommendations. Following this trend, we describe CURUMIM, an on...

Tourism is an important source of income of countries, since nowadays 10% of GDP corresponds to a direct, indirect or induced effect of tourism. In European countries like Spain, the activity reached numbers like 11% of GDP in 2016. Therefore, providing an efficient and personalised service for tourists has become an essential issue in the developm...

Temporal landmarks have been proved to be a helpful mechanism to deal with temporal planning problems, specifically to improve planners performance and handle problems with deadline constraints. In this paper, we show the strength of using temporal landmarks to handle the state trajectory constraints of PDDL3.0. We analyze the formalism of TempLM,...

Many tourist applications provide a personalized tourist agenda with the list of recommended activities to the user. These applications must undoubtedly deal with the constraints and preferences that define the user interests. Among these preferences, we can find those that define the travel style of the user, such as the rhythm of the trip, the nu...

This paper describes e-Tourism2.0, a web-based recommendation and planning system for tourism activities that takes into account the preferences that define the travel style of the user. e-Tourism2.0 features a recommender system with access to various web services in order to obtain updated information about locations, monuments, opening hours, or...

Many real-work smart environments make use of IoT to be provided with context-aware services. Additionally, these environments require making decisions based on predictions about future actions. This involves the use of goal-directed behaviour which may need reasoning about new goals. This paper is devoted to analyze when a new goal can be formulat...

In this paper, we present a smart tourism system that plans a tourist agenda and keeps track of the plan execution. A Recommendation System returns the list of places that best fit the individual tastes of the tourist and a planner creates a personalized agenda or plan with indication of times and durations of visits. The key component of the syste...

Nowadays, social networks store a massive amount of data, which can say a lot about our personality. Given the ease to access the internet everywhere at any time, many people use social networks in daily life, reflecting in a certain way their behaviour from the "real world" to the "virtual world", by storing in social networks what they like, hate...

This paper presents TempLM, a novel approach for handling temporal planning problems with deadlines. The proposal revolves around the concept of temporal landmark, a proposition that must be necessarily true in all solution plans to achieve the problem goals within their deadlines. The temporal landmarks extracted from the problem form a landmarks...

In this paper we present a temporal planning approach for handling problems with deadlines. The model relies on the extraction of temporal landmarks from the problem and the construction of a landmarks graph as a skeleton of the solution plan. A temporal landmark is a proposition that must be achieved in a solution plan to satisfy the problem deadl...

Over the last years, some remarkable recommender systems for group of users have been developed. When using most of these systems, each group member communicates his/her preferences to the system, which obtains a group profile as the result of an equal weighting of the individual preferences. This way, no member is particularly dissatisfied with th...

In this paper, we present samap, whose goal is to build a software tool to help different people visit different cities. This tool integrates modules that dynamically capture user models, determine lists of activities that can provide more utility to a user given the past experience of the system with similar users, and generates plans that can be...

n this article, a technique towards the generation of hybrid raster-attributes map for use in mobile devices is described. Our solution is based on coding the map attributes within an image using RGB values. The designed coding method enables the simultaneous storage of discrete thematic attributes and continuous quantitative attributes. This appro...

A key issue in group recommendation is how to combine the individual preferences of different users that form a group and elicit a profile that accurately reflects the tastes of all members in the group. Most Group Recommender Systems (GRSs) make use of some sort of method for aggregating the preference models of individual users to elicit a recomm...

In this paper, we present a work that is part of a running project, SAMAP 1 . The aim of the project is to make tourist plans for a user in an 'intelligent' way, considering its preferences to propose a list of activities that better adjusts to its profile. The application could run in any device with Internet connection capabilities, such as Perso...

One can find in the literature several approaches aimed at finding landmarks and orderings, each claiming to obtain an improvement over the first original approach. In this paper we propose a complementary view to landmarks exploitation that combines the advantages of each approach and come up with a novel technique that outperforms each individual...

Many known planning tasks have inherent constraints concerning the best order in which to achieve the goals. A number of research efforts have been made to detect such constraints and to use them for guiding search, in the hope of speeding up the planning process. We go beyond the previous approaches by considering ordering constraints not only ove...

Recommendation can be defined as the problem of selecting, among a set of items, those ones that are likely of interest to the user. In case of a group of users, recommendations should satisfy, as far as possible, the preferences of all the group members. In order to elicit the group preferences, we present two different mechanisms: the first one c...

This paper presents a recommender system for tourism based on the tastes of the users, their demographic classification and the places they have visited in former trips. The system is able to offer recommendations for a single user or a group of users. The group recommendation is elicited out of the individual personal recommendations through the a...

In this paper, we present a Multi Agent System aimed to support a user or a group of users on the planning of different leisure and tourist activities in a city. The system integrates agents that cooperate to dynamically capture the users profiles and to obtain a list of suitable and satisfactory activities for the user or for the group, by using t...

This paper presents a Generalist Recommender System Kernel (GRSK) and describes the differences of the recommendation process when it is applied to groups. The GRSK is able to work with any domain as long as the domain description is represented within an ontology. Several basic techniques like demographics, content-based or collaborative are used...

In this paper, we present a Multi Agent System aimed to support an user on the realization of different leisure and tourist activities in a city. The system integrates agents that cooperate to dynamically capture the user profile and to obtain a list of suitable and satisfactory activities for the user, by using the experience acquired through the...

This paper describes the main characteristics of GRSK, a Generalist Recommender System Kernel. It is a RS based on the semantic description of the domain, which allows the system to work with any domain as long as the data of this domain can be defined through an ontology representation. GRSK uses several Basic Recommendation and Hybrid Techniques...

e-Tourism is a tourist recommendation and planning application to assist users on the organization of a leisure and tourist agenda. First, a recommender system offers the user a list of the city places that are likely of interest to the user. This list takes into account the user demographic classification, the user likes in former trips and the pr...

This paper introduces a method for giving recommendations of tourist activities to a group of users. This method makes recommendations based on the group tastes, their demographic classification and the places visited by the users in former trips. The group recommendation is computed from individual personal recommendations through the use of techn...

This paper addresses the problem of group recommendation, that is, the selection of a set of items that are likely of interest to a group of users. To obtain the preferences of the group, we propose a negotiation mechanism between agents, each of them acting on behalf of one member of the group. This way, each user can define a different behaviour...

e-Tourism is a tourist recommendation and planning application to assist users on the organization of a leisure and tourist agenda. First, a recommender system offers the user a list of the city places that are likely of interest to the user. This list takes into account the user demographic classification, the user likes in former trips and the pr...

Deadline constraints have been recently introduced in PDDL3.0. The results obtained in the constraints domains in the last Planning Competition show that planners are not yet fully competitive. When dealing with deadline constraints the number of feasible solutions for a problem is reduced and thus it is specially relevant the ability to detect uns...

In this paper, we present a new technique to extract landmarks in a temporal context. This technique works iteratively over a temporal landmarks graph in order to obtain the skeleton of the final plan. Our approach consists in four stages: first, a temporal planning graph is built; then, a set of initial temporal landmarks is computed from this tem...

In many realistic planning domains, the exact duration of actions is only known at the instant of executing the action. This is the case, for instance, of temporal domains where it is common to find external factors that cause a delay in the execution of actions. In this paper we present an approach to obtain a plan for a temporal domain with delay...

The ability to decompose a problem into manageable sub-components is a necessity in complex problem-solving tasks. In planning, the application of a divide-and-conquer methodology is known as planning decomposition. This technique consists of the following: decomposing a problem into smaller components (subproblems), solving these subproblems indiv...

Recently, planning under temporal uncertainty is becoming a very important and active field within the AI planning community. In this paper we present a new approach to handle planning problems with uncertain duration of actions. The novelty of this approach is that the management of the temporal uncertainty in durative actions is done independentl...

This paper presents an approach to handle and satisfy time constraints when a temporal plan is to be instantiated over a real time line. This approach considers two types of con-straints: ¢ Domain/Environment constraints. We introduce the con-cept of delay in durational contexts. In real domains, the actual duration of a temporal action is highly d...

In order to let software applications use planning tech- nology, one of the needs consists on the knowledge ex- change between the planner component and the rest of components. Currently, one of the most widely used means of supporting this exchange in a declarative way is through the use of common ontologies. In this pa- per, we present our on-goi...

Este libro va destinado a todos aquellos estudiantes de primeros cursos de ingeniería en sus diferentes vertientes, incluyendo la ingeniería en informática, que reciben formación básica en programación de computadores en lenguaje C. No obstante, debido al nivel del libro, perfectamente podría ser utilizado también en academias, en cursos de bachill...

Planning is known to be a difficult task. One of the approaches used to reduce this difficulty is problem decomposition under divide-and-conquer method- ology. This paper introduces a new decomposition technique for planning prob- lems in STRIPS domains which is based on the idea of landmark, that is, literals that must be true in any solution plan...

In the last few years, AI planning techniques have experimented a great advance. One of the reasons for this big expansion is the International Planning Competition (IPC), which enforces the definition of language standards as PDDL+ and new benchmarks. In this paper, we present the new features of STeLLa, a planner that participated in the last IPC...

In this paper we present SimPlanner, an integrated planning and execution-monitoring system. SimPlanner allows the user to monitor the execution of a plan, interrupt this monitoring process to introduce new information from the world and repair the plan to get it adapted to the new situation.

We identify important intermediate planning goals, which we refer to as landmarks and present a method for extracting landmarks from an input planning problem. We also present a method for finding orders between landmarks which can be used during planning. These methods have been implemented and integrated with an example planning system. In the pa...

. Many known planning tasks have inherent constraints concerning the best order in which to achieve the goals. A number of research efforts have been made to detect such constraints and use them for guiding search, in the hope to speed up the planning process. We go beyond the previous approaches by defining ordering constraints not only over the (...

In the last few years, the field of planning in AI has experimented a great advance. Nowadays, one can use planners that solve complex problems in a few seconds. However, building good quality plans has not been a main issue. In this paper, we introduce a planning system whose aim is obtaining the optimal solution w.r.t. the number of actions and m...

In this paper we present a method for extracting important intermediate planning goals, and for finding orders between them which can then be used during planning. We have implemented this method and have integrated it with an example planning system, and in the paper we present results that support our expectation that these orders can lead to imp...

This paper is intended to identify the nature of resources and the roles they can play in planning problems, and to consider ways in which planning technology might be extended to handle them.

We introduce a new approach to planning in STRIPS-like domains based on an incremental local search process. This approach arises as an attempt to combine the advantages of a graph-based analysis and a partial-order planner. The search process is carried out by a four-stage algorithm. The starting point is a graph, which totally or partially encode...

In this paper, we show that despite the great success of some planning approaches, partial-order planning is still an efficient and valid approach,for tackling planning problems. The goal of this paper is to show,that the effort needed,by of a partial-order planner (POP) to solve a problem,can be dramatically reduced. By properly exploiting the pro...

. GraphPlan-like and SATPLAN-like planners have shown to outperform classical planners for most of the classical planning domains. However, these two propositional approaches do not exhibit good results for large-size problems due to the graph size they have to handle. In this paper we show a new approach for planning as an attempt to combine the a...

Planning is known to be a difficult task. One of the approaches used to reduce this difficulty is problem decomposition under divide-and-conquer method- ology. This paper introduces a new decomposition technique for planning prob- lems in STRIPS domains which is based on the idea of landmark, that is, literals that must be true in any solution plan...

Temporal constraints over actions and their effects or process states may appear in planning problems. In many real problems, the execution of a plan involves the use of resources, generally limited and shared. For this reason, an additional stage of scheduling of actions and resources in time becomes more necessary. In spite of the obtained result...