A central closure construction for certain extensions. Applications to Hopf algebra actions

Algebra extensions A < B where A is a left B-module such that the B-action extends the multiplication in A are ubiquitous. We encounter examples of such extensions in the study of group actions, group gradings or more general Hopf actions as well as in the study of the bimodule structure of an algebra. In this paper we are extending R.Wisbauer's method of constructing the central closure of a semiprime algebra using its multiplication algebra to those kinds of algebra extensions. More precisely if A is a k-algebra and B some subalgebra of End(A) that contains the multiplication algebra of A, then the self-injective hull \hat{A} of A as B-module becomes an k-algebra provided A does not contain any nilpotent B-stable ideals. We show that under certain assumptions \hat{A} can be identified with a subalgebra of the Martindale quotient ring of A. This construction is then applied to Hopf module algebras.Comment: LaTeX, 17 page

Understanding a Version of Multivariate Symmetric Uncertainty to assist in Feature Selection

In this paper, we analyze the behavior of the multivariate symmetric uncertainty (MSU) measure through the use of statistical simulation techniques under various mixes of informative and non-informative randomly generated features. Experiments show how the number of attributes, their cardinalities, and the sample size affect the MSU. We discovered a condition that preserves good quality in the MSU under different combinations of these three factors, providing a new useful criterion to help drive the process of dimension reduction

Directionality of THz emission from photoinduced gas plasmas

Forward and backward THz emission by ionizing two-color laser pulses in gas is investigated by means of a simple semi-analytical model based on Jefimenko's equation and rigorous Maxwell simulations in one and two dimensions. We find the emission in backward direction having a much smaller spectral bandwidth than in forward direction and explain this by interference effects. Forward THz radiation is generated predominantly at the ionization front and thus almost not affected by the opacity of the plasma, in excellent agreement with results obtained from a unidirectional pulse propagation model

Prevalence of Code Smells in Reinforcement Learning Projects

Reinforcement Learning (RL) is being increasingly used to learn and adapt application behavior in many domains, including large-scale and safety critical systems, as for example, autonomous driving. With the advent of plug-n-play RL libraries, its applicability has further increased, enabling integration of RL algorithms by users. We note, however, that the majority of such code is not developed by RL engineers, which as a consequence, may lead to poor program quality yielding bugs, suboptimal performance, maintainability, and evolution problems for RL-based projects. In this paper we begin the exploration of this hypothesis, specific to code utilizing RL, analyzing different projects found in the wild, to assess their quality from a software engineering perspective. Our study includes 24 popular RL-based Python projects, analyzed with standard software engineering metrics. Our results, aligned with similar analyses for ML code in general, show that popular and widely reused RL repositories contain many code smells (3.95% of the code base on average), significantly affecting the projects' maintainability. The most common code smells detected are long method and long method chain, highlighting problems in the definition and interaction of agents. Detected code smells suggest problems in responsibility separation, and the appropriateness of current abstractions for the definition of RL algorithms.Comment: Paper preprint for the 2nd International Conference on AI Engineering Software Engineering for AI CAIN202

Sensitive and specific detection of explosives in solution and vapour by surface-enhanced Raman spectroscopy on silver nanocubes

Surface-enhanced Raman spectroscopy (SERS) has been widely utilised as a sensitive analytical technique for the detection of trace levels of organic molecules. The detection of organic compounds in the gas phase is particularly challenging due to the low concentration of adsorbed molecules on the surface of the SERS substrate. This is particularly the case for explosive materials, which typically have very low vapour pressures, limiting the use of SERS for their identification. In this work, silver nanocubes (AgNCs) were developed as a highly sensitive SERS substrate with very low limit-of-detection (LOD) for explosive materials down to the femtomolar (10−15 M) range. Unlike typical gold-based nanostructures, the AgNCs were found suitable for the detection of both aromatic and aliphatic explosives, enabling detection with high specificity at low concentration. SERS studies were first carried out using a model analyte, Rhodamine-6G (Rh-6G), as a probe molecule. The SERS enhancement factor was estimated as 8.71 × 1010 in this case. Further studies involved femtomolar concentrations of 2,4-dinitrotoluene (DNT) and nanomolar concentrations of 1,3,5-trinitroperhydro-1,3,5-triazine (RDX), as well as vapour phase detection of DNT

Planeamiento de sistemas de distribución de energía eléctrica con generación distribuida utilizando búsqueda Tabú

El planeamiento de la expansión de los sistemas de distribución es de vital importancia para el análisis de sistemas eléctricos, pues permite encontrar la topología más adecuada y económica que se adapte a criterios técnicos y operativos, a través de la utilización de diversos modelos y técnicas matemáticas exactas y no exactas. Cada vez el análisis de dichos sistemas se vuelve más complejo, pues se deben incorporar una mayor cantidad de variables con el fin de acercarse más a lo que sucede en los sistemas reales: aspectos como la coordinación de protecciones, la necesidad de utilización de energías limpias para la generación de energía, los impactos en los niveles de confiabilidad y regulación de tensión en la red, la contribución en los niveles de pérdidas de potencia, entre otras situaciones pueden ser consideradas en el análisis, según sea la finalidad del modelo de planeamiento

Estudio de factibilidad para la creacion de una micro empresa textil destinada a la confeccion de ternos sastre para caballeros en la ciudad de Otavalo provincia de Imbabura

Desarrollar el estudio de factibilidad para la creación de una microempresa textil destinada a la confección de ternos para caballeros en la ciudad de Otavalo.El presente trabajo se enmarca dentro de un estudio descriptivo, que investiga el proceso de producción textil mas óptimos, ya que busca determinar la factibilidad para la implementación de la microempresa de confección de ternos estilo sastre para hombres de diferentes edades que se clasificaran de acuerdo a las tallas que existen en el mercado para los ternos formales de caballeros de todas las edades. Un factor importante que se debe destacar para la realización de este proyecto, es pretender ayudar al andamiaje productivo en esta clase de prenda textil, pues la estructura de producción en la ciudad de Otavalo es débil y las que se encuentra en mercado es de producción artesanal, de ahí la necesidad de promover una microempresa para el manejo técnico en los procesos productivos, para alcanzar mayores niveles de competitividad como también el tipo de maquinaria textil que se empleara para la fabricación de los ternos estilo sastre para hombre. El proyecto culminará con la evaluación de la factibilidad de la implementación de una microempresa textil, en la que se distingue los métodos de evaluación cualitativos y cuantitativos, los índices financieros y el análisis de sensibilidad; lo que permitirá verificar la viabilidad del proyecto.Ingenierí