Instituto Tecnológico Autónomo de México

About: Instituto Tecnológico Autónomo de México is a education organization based out in Mexico City, Mexico. It is known for research contribution in the topics: Politics & Population. The organization has 1098 authors who have published 2532 publications receiving 39083 citations. The organization is also known as: Instituto Tecnologico Autonomo de Mexico & Mexico Autonomous Institute of Technology.

Monitoring reduction in variability with the range

Abstract: When monitoring a process it is important to quickly detect increases and decreases in its variability. In addition to preventing any increase in the variability of the process and any deterioration in the quality of the output, it is also important to search for special causes that may result in a smaller process dispersion. Considering this, users should always try to monitor for both increases and decreases in the variability. The process variability is commonly monitored by means of a Shewhart range chart. For small subgroup sizes this control chart has a lower control limit equal to zero. To help monitor for both increases and decreases in variability, Shewhart charts with probability limits or runs rules can be used. CUSUM and EWMA charts based on the range or a function of the subgroup variance can also be used. In this paper a CUSUM chart based on the subgroup range is proposed. Its performance is compared with that of other charts proposed in the literature. It is found that for small subgroup sizes, it has an excellent performance and it thus represents a powerful alternative to currently utilized strategies.

Trajectory tracking passivity-based control for marine vehicles subject to disturbances

Abstract: In this paper we present a dynamic model of marine vehicles in both body-fixed and inertial momentum coordinates using port-Hamiltonian framework. The dynamics in body-fixed coordinates have a particular structure of the mass matrix that allows the application of passivity-based control design developed for robust energy shaping stabilisation of mechanical systems described in terms of generalised coordinates. As an example of application, we follow this methodology to design a passivity-based controller with integral action for fully actuated vehicles in six degrees of freedom that tracks time-varying references and rejects disturbances. We illustrate the performance of this controller in a simulation example of an open-frame unmanned underwater vehicle subject to both constant and time-varying disturbances. We also describe a momentum transformation that allows an alternative model representation of marine craft dynamics that resembles general port-Hamiltonian mechanical systems with a coordinate dependent mass matrix.

The Political Determinants of Economic Performance: Political Competition and the Sources of Growth

Abstract: The authors present and test a theory about the effects of political competition on the sources of economic growth. Using Mankiw, Romer, and Weil’s model of economic growth and data for roughly 80 countries, the authors show that political competition decreases the rate of physical capital accumulation and labor mobilization but increases the rate of human capital accumulation and (less conclusively) the rate of productivity change. The results suggest that political competition systematically affects the sources of growth, but those effects are cross-cutting, explainingwhy democracy itself may be ambiguous. These findingshelp clarify the debate about regime type and economic performance and suggest new avenues for research.

From numeric data to information granules

Abstract: Designing information granules used intensively in Granular Computing is of paramount relevance to the fundamentals of the discipline. Information granules are key functional components in granular models, granular classifiers, and granular decision-making models. The design of information granules is central to the discipline of Granular Computing. In this study, we introduce a way of designing information granules by combining the mechanisms of unsupervised and supervised learning and subsequently using the principle of justifiable granularity. An overall design process consists of two phases. First, the granulation process involves hierarchical clustering or K-means clustering. It is followed by a parametric refinement of information granules realized by the principle of justifiable granularity. The characterization of information granules is offered in terms of measures of coverage, specificity, and entropy. Experimental results including synthetic data and publicly available data are covered to demonstrate the performance of the proposed approach.

Bayesian Random Segmentation Models to Identify Shared Copy Number Aberrations for Array CGH Data.

Abstract: Array-based comparative genomic hybridization (aCGH) is a high-resolution, high-throughput technique for studying the genetic basis of cancer. The resulting data consist of log fluorescence ratios as a function of the genomic DNA location and provide a cytogenetic representation of the relative DNA copy number variation. Analysis of such data typically involves estimating the underlying copy number state at each location and segmenting regions of DNA with similar copy number states. Most current methods proceed by modeling a single sample / array at a time, and thus fail to borrow strength across multiple samples to infer shared regions of copy number aberrations. We propose a hierarchical Bayesian random segmentation approach for modeling aCGH data that uses information across arrays from a common population to yield segments of shared copy number changes. These changes characterize the underlying population and allow us to compare different population aCGH profiles to assess which regions of the genome ...