Guillermo De Ita

An Empirical Study of Oversampling and Undersampling Methods for LCMine an Emerging Pattern Based Classifier

Classifiers based on emerging patterns are usually more understandable for humans than those based on more complex mathematical models. However, most of the classifiers based on emerging patterns get low accuracy in those problems with imbalanced databases. This problem has been tackled through oversampling or undersampling methods, nevertheless, to the best of our knowledge these methods have not been tested for classifiers based on emerging patterns. Therefore, in this paper, we present an empirical study about the use of oversampling and undersampling methods to improve the accuracy of a classifier based on emerging patterns. We apply the most popular oversampling and undersampling methods over 30 databases from the UCI Repository of Machine Learning. Our experimental results show that using oversampling and undersampling methods significantly improves the accuracy of the classifier for the minority class.

A Threshold for a Polynomial Solution of n2SAT

The nSAT problem is a classical nP-complete problem even for monotone, Horn and two conjunctive formulas (the last known as n2SAT). We present a novel branch and bound algorithm to solve the n2SAT problem exactly. Our procedure establishes a new threshold where n2SAT can be computed in polynomial time. We show that for any 2-CF formula F with n variables where n2SAT(F) ≤ p(n), for some polynomial p, n2SAT(F) is computed in polynomial time. This is a new way to measure the degree of difficulty for solving n2SAT and, according to such measure our algorithm allows to determine a boundary between ‘hard’ and ‘easy’ instances of the n2SAT problem.

Smart Tourism in 1-Click

Abstract The use and application of technology is the challenge of tourism for the XXI century. Thus, a novel application for mobile devices is deployed. Our application allows you to browse all points of interest to the user such as hotels, restaurants, attractions, etc. Our application incorporates at first instance the city of Mexico, one of the cities most visited by tourists. With respect to Mexico city we added three important features to our application. First, the user can indicate whether traveling by car or walks. Second, user can choose city area to visit, as well as the maximum distance at which he want to move. Third, our application will generate the shortest route to follow. Secondly but no less important, our application incorporates the city of Puebla, a city declared World Heritage. It support the efficiently tourists in planning their stay in Puebla City showing user a set of tourist places and services, both useful for tourists, of which user chooses those who want to know. From this set of selected places our application determines the shortest path using the traveling salesman algorithm. Also, emergency services information about all local points is available. Generation of custom path is integrated, allowing user to have Google maps with all places to visit with a true an accurate location. Finally, our application allows the user to display maps of tourist places in real time without the GPS service, instead we use GPRS via Wireless Application Protocol with the Google Maps API.

Estimating the relevance on Communication Lines Based on the Number of Edge Covers

Abstract Counting the number of edge covers on graphs, denoted as the #Edge_Covers problem, is a #P-complete problem. Knowing the number of edge covers is useful for estimating the relevance of the lines in a communication network, which is an important measure in the reliability analysis of a network. In this paper, we present efficient algorithms for solving the #Edge_Covers problem on the most common network topologies, namely, Bus, Stars, Trees and Rings. We show that if the topology of the network G does not contain intersecting cycles (any pair of cycles with common edges), then the number of edge covers can be computed in linear time on the size of G.

An algorithm to approximate the chromatic number of graphs

In this paper, we present an algorithm to approximate the chromatic number of a graph. Our proposal is based on the construction of maximal independent set. We experimentally show that our proposal improves the average degree approximation proposed by De Ita et. al. [10]. Finally, our proposal is compared against JGraphT and Sage which contain a model for computing the chromatic number of a graph.

A Linear Time Algorithm for Computing #2SAT for Outerplanar 2-CNF Formulas

Although the satisfiability problem for two Conjunctive Normal Form formulas (2SAT) is polynomial time solvable, it is well known that #2SAT, the counting version of 2SAT is #P-Complete. However, it has been shown that for certain classes of formulas, #2SAT can be computed in polynomial time. In this paper we show another class of formulas for which #2SAT can also be computed in lineal time, the so called outerplanar formulas, e.g. formulas whose signed primal graph is outerplanar. Our algorithm’s time complexity is given by \(O(n+m)\) where n is the number of variables and m the number of clauses of the formula.

Modelling 3-Coloring of Polygonal Trees via Incremental Satisfiability.

A novel method to model the 3-coloring on polygonal tree graphs is presented. This proposal is based on the logical specification of the constraints generated for a valid 3-coloring on polygonal graphs. In order to maintain a polynomial time procedure, the logical constraints are formed in a dinaymic way. At the same time, the graph is traversing in postorder, resulting in a polynomial time instance of the incremental satisfiability problem. This proposal can be extended for considering other polynomial time instances of the 3-coloring problem.

Search for Answers in Domain Specific Supported by Intelligent Agents

Search for answers in specific domains is a new milestone in question answering. Traditionally, question answering has focused on general domain questions. Thus, the most relevant answers (or passages) are selected according to the type of question and the Named Entities included in the possible answers. In this paper, we present a novel approach on question answering over specific (or technical) domains. This proposal allows us to answer questions such as “What article is appropriate for ... “, “What are the articles related to ... “, these kind of questions cannot be answered by a general question answering system. Our approach is based on a set of laws of a specific domain, which contain a large set of laws regarding the work organized into a hierarchy. We consider generic concepts such as “article” semantic categories. Our results on the corpus of Federal Labor Law show that this approach is effective and highly reliable.

Computing the Clique-Width of Polygonal Tree Graphs

Similar to the tree-width (twd), the clique-width (cwd) is an invariant of graphs. There is a well-known relationship between the tree-width and clique-width for any graph. The tree-width of a special class of graphs called polygonal trees is 2, so the clique-width for those graphs is smaller or equal than 6. In this paper we show that we can improve this bound to 5 and we present a polynomial time algorithm which computes the 5-expression.

Efficient Counting of the Number of Independent Sets on Polygonal Trees

We present a method to compute the number of independent sets for two basic graph patterns: simple cycles and trees. We show how to extend this initial method for processing efficiently more complex graph topologies.