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Potential Search: A Bounded-Cost Search Algorithm

AAAI Conferences

In this paper we address the following search task: find a goal with cost smaller than or equal to a given fixed constant. This task is relevant in scenarios where a fixed budget is available to execute a plan and we would like to find such a plan with minimum search effort. We introduce an algorithm called Potential search (PTS) which is specifically designed to solve this problem. PTS is a best-first search that expands nodes according to the probability that they will be part of a plan whose cost is less than or equal to the given budget. We show that it is possible to implement PTS even without explicitly calculating these probabilities, when a heuristic function and knowledge about the error of this heuristic function are given. In addition, we also show that PTS can be modified to an anytime search algorithm. Experimental results show that PTS outperforms other relevant algorithms in most cases, and is more robust.


Solving Graph Coloring Problems Using Cultural Algorithms

AAAI Conferences

In this paper, we combine a novel Sequential Graph Coloring Heuristic Algorithm (SGCHA) with a non-systematic method based on a cultural algorithm to solve the graph coloring problem (GCP). The GCP involves finding the minimum number of colors for coloring the graph vertices such that adjacent vertices have distinct colors. In our solving approach, we first use an estimator which is implemented with SGCHA to predict the minimum colors. Then, in the non-systematic part which has been designed using cultural algorithms, we improve the prediction. Various components of the cultural algorithm have been implemented to solve the GCP with a self adaptive behavior in an efficient manner. As a result of utilizing the SGCHA and a cultural algorithm, the proposed method is capable of finding the solution in a very efficient running time. The experimental results show that the proposed algorithm has a high performance in time and quality of the solution returned for solving graph coloring instances taken from DIMACS website. The quality of the solution is measured here by comparing the returned solution with the optimal one.


Happy Movie: A Group Recommender Application in Facebook

AAAI Conferences

In this paper we introduce our recommender Happy Movie, a Facebook application for movie recommendation to groups. This system exploits information about the social relationships and behaviour of the users to provide better recommendations. Our previous works have shown that social factors improve the recommendation results. However it required many questionnaires to be filled for obtaining the social information, so we have moved to a social network environment where this information is easily available.


Commonsense Knowledge Extraction Using Concepts Properties

AAAI Conferences

This paper presents a semantically grounded method for extracting commonsense knowledge. First, commonsense rules are identified, e.g., one cannot see imaginary objects. Second, those rules are combined with a basic semantic representation in order to infer commonsense knowledge facts, e.g. one cannot see a flying carpet. Further combinations of semantic relations with inferred commonsense facts are proposed and analyzed. Results show that this novel method is able to extract thousands of commonsense facts with little human interaction and high accuracy.


EcoLexicon and FunGramKB: Applying COREL to Domain-Specific Knowledge

AAAI Conferences

EcoLexicon is a multilingual terminological knowledge base (TKB) on the environment. It is currently being converted into a domain-specific ontology, however, ontological properties are modelled according to surface semantics. For this reason, we are integrating our TKB in the form of a “satellite ontology” into FunGramKB, a multipurpose knowledge base specifically designed for natural language understanding. We explain how the dynamism of environmental concepts can benefit from a formal description in meaning postulates and their inclusion in FunGramKB Cognicon scripts. This would lead to the automatic generation of flexible conceptual networks and definitional templates across different contexts.


The Multi-Round Balanced Traveling Tournament Problem

AAAI Conferences

Given an n -team sports league, the Traveling Tournament Problem (TTP) seeks to determine an optimal double round-robin schedule minimizing the sum total of distances traveled by the n teams as they move from city to city. In the TTP, the number of "rounds" is fixed at r = 2. In this paper, we propose the Multi-Round Balanced Traveling Tournament Problem (mb-TTP), inspired by the actual league structure of Japanese professional baseball, where n = 6 teams play 120 intra-league games over r = 8 rounds, subject to various constraints that ensure competitive balance. These additional balancing constraints enable us to reformulate the 2 k -round mb-TTP as a shortest path problem on a directed graph, for all k >= 1. We apply our theoretical algorithm to the 6-team Nippon (Japanese) Professional Baseball Central League, creating a distance-optimal schedule with 57836 kilometres of total travel, a 26.8% reduction compared to the 79067 kilometres traveled by these six teams during the 2010 regular season.


Number of Words Versus Number Ideas: Finding a Better Predictor of Writing Quality

AAAI Conferences

This study examines the relation between the linguistic features of freewrites and human assessments of freewriting quality. This study builds upon the authors’ previous studies in which a model was developed based on the linguistic features of freewrites written by 9th and 11th grade students to predict freewrite quality. The current study reexamines this model using number of propositions as a predictor instead of number of words because the number of propositions was expected to be a better proxy for number of ideas in contrast to simple text length. The results indicated that there were only slight advantages for using a measure for number of propositions, indicating that from an artificial intelligence perspective, the number of words was the better measure.


Planning for Loosely Coupled Agents Using Partial Order Forward-Chaining

AAAI Conferences

We investigate a hybrid between temporal partial-order and forward-chaining planning where each action in a partially ordered plan is associated with a partially defined state. The focus is on centralized planning for multi-agent domains and on loose commitment to the precedence between actions belonging to distinct agents, leading to execution schedules that are flexible where it matters the most. Each agent, on the other hand, has a sequential thread of execution reminiscent of forward-chaining. This results in strong and informative agent-specific partial states that can be used for partial evaluation of preconditions as well as precondition control formulas used as guidance. Empirical evaluation shows the resulting planner to be competitive with TLplan and TALplanner, two other planners based on control formulas, while using a considerably more expressive and flexible plan structure.


Differential Linguistic Features in U.S. Immigration Newspaper Articles: A Contrastive Corpus Analysis Using the Gramulator

AAAI Conferences

Our corpus comprises 752 texts, culled from newspapers of U.S. border states (approximately 75 texts per state). Immigration is a national issue in the United States; Because four states border Mexico, we selected four however, regional implications differ because of matching states (of the 11) that border Canada. To do so, immigrants' varying effects on local economies. These we considered the following criteria for all 15 terrestrial implications are made manifest in the reportage of local border states: total population, immigrant population, newspapers, which, while ostensibly portraying length of international border, and political leaning. These "objective" language, may reveal the narrative of local data were input into a custom PERL script designed to perspectives on national issues.


Ontological Support for Creative Writing

AAAI Conferences

In this paper we propose an ontological framework for tools facilitating creative writing and story reading. It is based on an ontology implemented as a topic map and employs linguistic analysis methods for discovering conceptual entities in the text.