Juan Barbosa - Academia.edu (original) (raw)

Papers by Juan Barbosa

American Journal of Hypertension, 2001

Diabetes-metabolism Research and Reviews, 2002

BackgroundType 2 diabetes is a growing problem in Mexico. The present study was undertaken to eva... more BackgroundType 2 diabetes is a growing problem in Mexico. The present study was undertaken to evaluate the efficacy and safety of rosiglitazone 2 mg or 4 mg twice daily (bd) in combination with metformin 2.5 g/day in Mexican patients whose type 2 diabetes was inadequately controlled with metformin alone.Type 2 diabetes is a growing problem in Mexico. The present study was undertaken to evaluate the efficacy and safety of rosiglitazone 2 mg or 4 mg twice daily (bd) in combination with metformin 2.5 g/day in Mexican patients whose type 2 diabetes was inadequately controlled with metformin alone.MethodsThis randomized, double-blind, placebo-controlled study was conducted at four centers in Mexico. A total of 116 patients were randomized to metformin 2.5 g/day plus placebo (n=39), metformin 2.5 g/day plus rosiglitazone 2 mg bd (n=37), or metformin 2.5 g/day plus rosiglitazone 4 mg bd (n=40) for 26 weeks.This randomized, double-blind, placebo-controlled study was conducted at four centers in Mexico. A total of 116 patients were randomized to metformin 2.5 g/day plus placebo (n=39), metformin 2.5 g/day plus rosiglitazone 2 mg bd (n=37), or metformin 2.5 g/day plus rosiglitazone 4 mg bd (n=40) for 26 weeks.ResultsMean hemoglobin A1c (HbA1c) levels decreased significantly from baseline to Week 26 in the rosiglitazone 2 mg bd (−0.7%; p=0.0052) and 4 mg bd (−1.2%; p=0.0008) groups, but increased in the placebo group (+0.3%; p=0.2651). Mean fasting plasma glucose and fructosamine levels also improved significantly with metformin plus rosiglitazone therapy in a dose-ordered manner compared with placebo (p≤0.0019 and p=0.0006, respectively). C-peptide and immunoreactive insulin levels were decreased from baseline in both rosiglitazone groups. Although mean increases in total cholesterol, low-density lipoprotein (LDL)-cholesterol, and high-density lipoprotein (HDL)-cholesterol were observed in the rosiglitazone groups, the total cholesterol:HDL-cholesterol ratio remained unchanged. The proportion of patients with one or more adverse events was similar across all three groups. There were no cases of hepatotoxicity.Mean hemoglobin A1c (HbA1c) levels decreased significantly from baseline to Week 26 in the rosiglitazone 2 mg bd (−0.7%; p=0.0052) and 4 mg bd (−1.2%; p=0.0008) groups, but increased in the placebo group (+0.3%; p=0.2651). Mean fasting plasma glucose and fructosamine levels also improved significantly with metformin plus rosiglitazone therapy in a dose-ordered manner compared with placebo (p≤0.0019 and p=0.0006, respectively). C-peptide and immunoreactive insulin levels were decreased from baseline in both rosiglitazone groups. Although mean increases in total cholesterol, low-density lipoprotein (LDL)-cholesterol, and high-density lipoprotein (HDL)-cholesterol were observed in the rosiglitazone groups, the total cholesterol:HDL-cholesterol ratio remained unchanged. The proportion of patients with one or more adverse events was similar across all three groups. There were no cases of hepatotoxicity.ConclusionAddition of rosiglitazone 2 mg bd and 4 mg bd to metformin therapy improved glycemic control in Mexican patients whose type 2 diabetes was inadequately controlled by metformin alone. Furthermore, the combination of rosiglitazone plus metformin was well tolerated. Copyright © 2002 John Wiley & Sons, Ltd.Addition of rosiglitazone 2 mg bd and 4 mg bd to metformin therapy improved glycemic control in Mexican patients whose type 2 diabetes was inadequately controlled by metformin alone. Furthermore, the combination of rosiglitazone plus metformin was well tolerated. Copyright © 2002 John Wiley & Sons, Ltd.

The present paper approaches the loading distribution of trucks for Product Transportation as a r... more The present paper approaches the loading distribution of trucks for Product Transportation as a rich problem. This is formulated with the classic Bin Packing Problem and five variants associated with a real case of study. A state of the art review reveals that related work deals with three variants at the most. Besides, they do not consider its relation with the vehicle routing problem. For the solution of this new rich problem a heuristic-deterministic algorithm was developed. It works together with a metaheuristic algorithm to assign routes and loads. The results of solving a set of real world instances show an average saving of three vehicles regarding their manual solution; this last needed 180 minutes in order to solve an instance and the actual methodology takes two minutes. On average, the demand was satisfied in 97.45%. As future work the use of a non deterministic algorithm is intended.

Microwave assisted extraction for mercury speciation analysis

Mikrochimica Acta, 2011

The application of microwave-assisted extraction (MAE) to the work-up of environmental and biolog... more The application of microwave-assisted extraction (MAE) to the work-up of environmental and biological samples in the study of mercury speciation analysis has increased in recent years and is now increasingly accepted as a standard approach. The review provides a brief theoretical background of microwave heating and the basic principles of microwave energy used for extraction. The advantages and disadvantages of (a) MAE techniques, (b) the influence of the main parameters affecting the extraction, (c) statistical optimization approaches, and (d) strategies for method validation also are highlighted. Recent applications of MAE to mercury species analyses in biological samples, soils, sediments, and crude oil samples are surveyed and critically reviewed. In addition, comparisons of its use with other well-established extraction procedures are discussed. Figure Microwave-assisted extraction has become a very useful sample preparation techniques in the study of mercury speciation in environmental and biological samples

A Distributed Metaheuristic for Solving a Real-World Scheduling-Routing-Loading Problem

In this paper a real and complex transportation problem including routing, scheduling and loading... more In this paper a real and complex transportation problem including routing, scheduling and loading tasks is presented. Most of the related works only involve the solution of routing and scheduling, as a combination of up to five different types of VRPs (Rich VRP), leaving away the loading task, which are not enough to define more complex real-world cases. We propose a solution methodology for transportation instances that involve six types of VRPs, a new constraint that limits the number of vehicles that can be attended simultaneously and the loading tasks. They are solved using an Ant Colony System algorithm, which is a distributed metaheuristic. Results from a computational test using real-world instances show that the proposed approach outperforms the transportation planning related to manual designs. Besides a well-known VRP benchmark was solved to validate the approach.

Less Expensive Formulation for a Realistic Routing-Scheduling-Loading Problem (RoSLoP

In this paper the Routing-Scheduling-Loading Problem (RoSLoP) is approached. This is a rich bin p... more In this paper the Routing-Scheduling-Loading Problem (RoSLoP) is approached. This is a rich bin packing (BPP) and vehicle routing (VRP) problem formulated to satisfy the transportation requirements of a bottling company located in Mexico. The initial formulation of the problem uses 29 integer variables and 30 constraints making difficult to find the exact solution even for small instances. In this work it is proposed a transformation function that reduces the size of the problem formulation which allows obtaining the optimal solution of small instances using an exact algorithm. Experimental results of the performance evaluation of an approximated solution method, with regard to the optimal solution, are showed. It is important to emphasize, that this is the first time that this kind of evaluation is carried out for RoSLoP. In the experiments a set of 12 test instances were selected from the company database. The experimental evidence shows that the transformation function reduces 97% the number of customers orders. The percentage quality error for the traveled distance was 0% and for the vehicles used was 6.19%. Now these results can be used to evaluate the performance of any new approximation solution method of RoSLoP.

A genetic distance metric to discriminate the selection of algorithms for the general ATSP problem

Journal of Intelligent and Fuzzy Systems, 2010

The only metric that had existed so far to determine the best algorithm for solving an general As... more The only metric that had existed so far to determine the best algorithm for solving an general Asymmetric Traveling Salesman Problem (ATSP) instance is based on the number of cities; nevertheless, it is not sufficiently adequate for discriminating the best algorithm for solving an ATSP instance, thus the necessity for devising a new metric through the use of data-mining techniques. In this paper we propose:(1) the use of a genetic distance metric for improving the selection of the algorithms that best solve a given instance of the ATSP and ...

$Research paper thumbnail of Contamination and chemical fractionation of heavy metals in street dust from the Metropolitan Area of Monterrey, Mexico$

Contamination and chemical fractionation of heavy metals in street dust from the Metropolitan Area of Monterrey, Mexico

Environmental Technology, 2011

The prevalence of heavy metal pollution and mobility of both Pb and Cd was investigated in street... more The prevalence of heavy metal pollution and mobility of both Pb and Cd was investigated in street dust samples from the Metropolitan Area of Monterrey (MAM) in northern Mexico. Street dust samples from 30 selected sites were analysed for their content of Zn, Cd, Pb, Cr and Ni after digestion according to US EPA Method 3051. Multivariate analysis including correlation coefficient analysis, Principal Component Analysis and Cluster Analysis was used to analyse the data and identify possible sources of these heavy metals. Compared with background values, elevated concentrations of Pb (300 mg kg−1), Cd (7.6 mg kg−1) and Cr (78 mg kg−1) were observed in street dust of MAM. Based on multivariate statistical approaches, the studied elements were classified in three main sources: (1) Cr, Ni and Zn mainly derived from industrial activities; (2) Cd originating from traffic‐related activities; and (3) Pb associated with vehicular emissions. A sequential extraction procedure using the Tessier method was applied to evaluate the mobility of Pb and Cd in street dust. The majority of Pb was associated with the residual fraction followed by the carbonate fraction. The majority of Cd was associated with the residual fraction. These results indicated that the mobility was higher in Pb (26%) compared with Cd (11%), posing a potential risk to the environment.

Dynamic Allocation of Data-Objects in the Web, Using Self-tuning Genetic Algorithms

In this paper, a new mechanism for automatically obtaining some control parameter values for Gene... more In this paper, a new mechanism for automatically obtaining some control parameter values for Genetic Algorithms is presented, which is independent of problem domain and size. This approach differs from the traditional methods which require knowing the problem domain first, and then knowing how to select the parameter values for solving specific problem instances. The proposed method uses a sample of problem instances, whose solution allows to characterize the problem and to obtain the parameter values. To test the method, a combinatorial optimization model for data-object allocation in the Web (known as DFAR) was solved using Genetic Algorithms. We show how the proposed mechanism allows to develop a set of mathematical expressions that relates the problem instance size to the control parameters of the algorithm. The expressions are then used, in on-line process, to control the parameter values. We show the last experimental results with the self-tuning mechanism applied to solve a sample of random instances that simulates a typical Web workload. We consider that the proposed method principles must be extended to the self-tuning of control parameters for other heuristic algorithms.

Iterated Local Search Algorithm for the Linear Ordering Problem with Cumulative Costs (LOPCC

In this article we approach the linear ordering problem with cumulative costs (LOPCC). Bertacco d... more In this article we approach the linear ordering problem with cumulative costs (LOPCC). Bertacco developed this problem [2] and propose two exact algorithms, due to the complexity of the problem Duarte propose a Tabu algorithm for LOPCC [3] and until now that algorithm is the state of the art. In this ongoing research we propose a set of iterated local search algorithms (ILS) to solve the LOPCC. The experimental evidence shows that the performance of the iterated local search algorithms evaluated have similar quality to the best solution reported and get better efficiency than the reference solution. Also with the local search algorithms we improve the best known solution for 32 instances. Now we are working in developing new algorithms with population metaheuristics.

Distribution Design in Distributed Databases Using Clustering to Solve Large Instances

In this paper we approach the solution of large instances of the distribution design problem. The... more In this paper we approach the solution of large instances of the distribution design problem. The traditional approaches do not consider that the size of the instances can significantly reduce the efficiency of the solution process, which only involves a model of the problem and a solution algorithm. We propose a new approach that incorporates multiple models and algorithms and mechanisms for instance compression, for increasing the scalability of the solution process. In order to validate the approach we tested it on a new model of the replicated version of the distribution design problem which incorporates generalized database objects, and a method for instance compression that uses clustering techniques. The experimental results, utilizing typical Internet usage loads, show that our approach permits to reduce at least 65% the computational resources needed for solving large instances, without significantly reducing the quality of its solution.

An Ant Colony System Algorithm to Solve Routing Problems Applied to the Delivery of Bottled Products

This work presents a methodology of solution for the well-known vehicle routing problem (VRP) bas... more This work presents a methodology of solution for the well-known vehicle routing problem (VRP) based on an ant colony system heuristic algorithm (ACS), which is applied to optimize the delivery process of RoSLoP (Routing-Scheduling-Loading Problem) identified in the company case of study. A first version of this algorithm models six variants of VRP and its solution satisfies the 100% of demands of the customers. The new version of the algorithm can solve 11 variants of VRP as a rich VRP. Experiments were carried out with real instances. The new algorithm shows a saving of two vehicles with regard to the first version, reducing the operation costs of the company. These results prove the viability of using heuristic methods and optimization techniques to develop new software applications.

Multiple Local Searches to Balance Intensification and Diversification in a Memetic Algorithm for the Linear Ordering Problem

The Linear Ordering problem (LOP) is an NP-hard problem, which has been solved using different me... more The Linear Ordering problem (LOP) is an NP-hard problem, which has been solved using different metaheuristic approaches. The best solution for this problem is a memetic algorithm, which uses the traditional approach of hybridizing a genetic algorithm with a single local search; on the contrary, in this paper we present a memetic solution hybridized with multiple local searches through all the memetic process. Experimental results show that using the best combination of local searches, instead of a single local search, the performance for XLOLIB instances is improved by 11.46% in terms of quality of the solution. For the UB-I instances, the proposed algorithm obtained a 0.12% average deviation from the best known solutions, achieving 17 new best known solutions. A Wilcoxon test was performed, ranking the proposed memetic algorithm as the second best solution of the state of the art for LOP. The results show that the multiple local searches approach can be more effective to get a better control in balancing intensification/diversification than the single local search approach.

This paper is based on a project at the University of Barcelona to develop the skills to diagnose... more This paper is based on a project at the University of Barcelona to develop the skills to diagnose the Generalized Anxiety Disorder (GAD) in students of psychology and psychiatry using a chatbot. The problem we address in this paper is to convert a chatbot in an emotional conversational agent capable of generating a believable and dynamic dialogue in natural language. For it, the dialogues convey traits of personality, emotions and its intensity. We propose to make an AIML language extension for the generation of believable dialogue, this extension will allow to create a more realistic scenario for the student to diagnose the condition simulated by the conversational agent. In order to measure the perception of the emotional state of the ECA expressed by the speech acts a survey was applied.

Ontology-Based Approach for Semi-automatic Generation of Subcategorization Frames for Spanish Verbs

This work deals with the semi-automatic generation of subcategorization frames (SCFs) of Spanish ... more This work deals with the semi-automatic generation of subcategorization frames (SCFs) of Spanish verbs; specifically, given a set of verbs in Spanish and their respective sense, their SCFs are obtained. The acquisition of SCFs in Spanish has been approached in different works: in some the frames are generated manually, while in others they are obtained semi-automatically from a tagged corpus; unfortunately in this case, the results depend on the characteristics of the texts used. The method proposed in this document combines an ontology-based approach (through lexical relations of verbs) and linguistic knowledge (functional class of verbs). The relations among base verbs and other verbs were obtained from the Spanish WordNet ontology, which contains lexical relations among words. Also, the existing relation between the SCF and the functional class of verbs was used to generate the SCFs. In order to evaluate the method the SCFs for 44 base verbs were generated manually, from which 239 SCFs were semi-automatically generated and validated, yielding an accuracy of 89.38%.

A Domain Independent Natural Language Interface to Databases Capable of Processing Complex Queries

We present a method for creating natural language interfaces to databases (NLIDB) that allow for ... more We present a method for creating natural language interfaces to databases (NLIDB) that allow for translating natural language queries into SQL. The method is domain independent, i.e., it avoids the tedious process of configuring the NLIDB for a given domain. We automatically generate the domain dictionary for query translation using semantic metadata of the database. Our semantic representation of a query is a graph including information from database metadata. The query is translated taking into account the parts of speech of its words (obtained with some linguistic processing). Specifically, unlike most existing NLIDBs, we take seriously auxiliary words (prepositions and conjunctions) as set theory operators, which allows for processing more complex queries. Experimental results (conducted on two Spanish databases from different domains) show that treatment of auxiliary words improves correctness of translation by 12.1%. With the developed NLIDB 82of queries were correctly translated (and thus answered). Reconfiguring the NLIDB from one domain to the other took only ten minutes.

This paper present the treatment of prepositions and conjunctions in natural language interfaces ... more This paper present the treatment of prepositions and conjunctions in natural language interfaces to databases (NLIDB) that allows better translation of queries expressed in natural language into formal languages. Prepositions and conjunctions weren’t sufficiently studied for their usage in NLIDBs, because most of the NLIDBs just look for keywords in the sentences and focus their analysis on nouns and verbs getting rid of auxiliary words in the query. This paper shows that prepositions and conjunctions can be represented as operations using formal set theory. Additionally, since prepositions and conjunctions keep their meaning in any context, their treatment is domain independent. In our experiments we used Spanish language. We validate our approach using two databases; Northwind and Pubs of SQL Server, with a corpus of 198 different queries for the first one and 70 queries for the second one. The 84% of queries were translated correctly for the database Northwind and 80% for Pubs.

The fast growth of Internet is creating a society where the demand on information storage, organi... more The fast growth of Internet is creating a society where the demand on information storage, organization, access, and analysis services is continuously growing. This constantly increases the number of inexperienced users that need to access databases in a simple way. Together with the emergence of voice interfaces, such a situation foretells a promising future for database querying systems using natural language interfaces. We describe the architecture of a relational database querying system using a natural language (Spanish) interface, giving a brief explanation of the implementation of each of the constituent modules: lexical parser, syntax checker, and semantic analyzer.

Automatic Extraction of Hyponymy-Hypernymy Lexical Relations between Nouns from a Spanish Dictionary

In this paper a method is presented which permits to automatically extract lexical-semantic relat... more In this paper a method is presented which permits to automatically extract lexical-semantic relations between nouns (specifically for concrete nouns since they have a well structured taxonomy). From the definitions of the entries in a Spanish dictionary, the hypernym of an entry is extracted from the entry definition according to the basic assumption that the first noun in the definition is the entry hypernym. After obtaining the hypernym for each entry, multilayered hyponymy-hyperonymy relations are generated from a noun, which is considered the root of the domain. The domains for which this approach was tested were zoology and botany. Five levels of hyponymy-hypernymy relations were generated for each domain. For the zoology domain a total of 1,326 relations was obtained with an average percentage of correctly generated relations (precision) of 84.31% for the five levels. 91.32% of all the relations of this domain were obtained in the first three levels, and for each of these levels the precision exceeds 96%. For the botany domain a total of 1,199 relations was obtained, with an average precision of 71.31% for the five levels. 90.76% of all the relations of this domain were obtained in the first level, and for this level the precision exceeds 99%.

We thought that, virtual reality cannot merely be reduced to a hardware system, another way to ac... more We thought that, virtual reality cannot merely be reduced to a hardware system, another way to achieve the optimal experience, is to produce a sense of immersion associated to an emotional and social experience inside the virtual environment. We believe that Virtual Characters that express a social and emotional behavior in their interaction could produce a sense of immersion in the user that interact with them. We propose to use this kind of character to develop social and emotional interfaces, capable to produce a believable Social Interaction.