A tight MIP formulation of the unit commitment problem with start-up and shut-down constraints

This paper provides the convex hull description of the single thermal Unit Commitment (UC) problem with the following basic operating constraints: (1) generation limits, (2) start-up and shut-down capabilities, and (3) minimum up and down times. The proposed constraints can be used as the core of any unit commitment formulation to strengthen the lower bound in enumerative approaches. We provide evidence that dramatic improvements in computational time are obtained by solving the self-UC problem and the network-constrained UC problem with the new inequalities for different case studies

Classification, Potential Role, and Modeling of Power-to-Heat and Thermal Energy Storage in Energy Systems

Most of the power-to-heat and thermal energy storage technologies are mature and already impact the European energy transition. However, detailed models of these technologies are usually very complex, making it challenging to implement them in large-scale energy models, where simplicity, e.g., linearity and appropriate accuracy, are desirable due to computational limitations. In the literature, the main power-to-heat and thermal energy storage technologies across all sectors have not been clearly identified and characterized. Their potential roles have not been fully discussed from the European perspective, and their mathematical modeling equations have not been presented in a compiled form. This paper contributes to the research gap in three main parts. First, it identifies and classifies the major power-to-heat and thermal energy storage technologies that are climate-neutral, efficient, and technologically matured to supplement or substitute the current fossil fuel-based heating. The second part presents the technology readiness levels of the identified technologies and discusses their potential role in a sustainable European energy system. The third part presents the mathematical modeling equations for the technologies in large-scale optimization energy models. We identified electric heat pumps, electric boilers, electric resistance heaters, and hybrid heating systems as the most promising power-to-heat options. We grouped the most promising thermal energy storage technologies under four major categories. Low-temperature electric heat pumps, electric boilers, electric resistance heaters, and sensible and latent heat storages show high technology readiness levels to facilitate a large share of the heat demand. Finally, the mathematical formulations capture the main effects of the identified technologies

MODELO DE COSTEO PARA LA VALUACIÓN DE PRODUCTOS DE SOFTWARE

ResumenEl proceso formativo de profesionistas de la industria del software en las Instituciones de Educación Superior (IES), abarca una serie de disciplinas y técnicas necesarias para la producción de software de calidad. Sin embargo, un aspecto que no suele ser tratado a detalle es lo correspondiente a la valuación, es decir, asociar un valor monetario a dichos proyectos, en la mayoría de los casos se enseña a desarrollar el software pero no a cotizarlo. Este artículo presenta un modelo que permite valuar proyectos de software, considerando desde los aspectos técnicos propios del desarrollo e implementación, hasta cuestiones contables y tributarias, todo ello aplicable tanto a empresas que producen software para otras organizaciones, como a departamentos o áreas de desarrollo inmersas en las empresas, que se encargan de desarrollar y mantener sus propios sistemas.Palabras clave: Tamaño del software, puntos de función, valuación. AbstractThe training process of professionals of the software industry in the Institutions of Higher Education that includes one set of disciplines and techniques necessary for the production of quality software. However, one aspect that is not usually dealt with in detail is valuation, that is, to associate a monetary value with such projects, in most cases it is taught to develop the software but not to quote it. This article presents a model that allows valuing software projects, considering from the technical aspects of development and implementation, to accounting and tax issues, all applicable to companies that produce software for other organizations, as well as departments or areas of development immersed in companies, which are responsible for developing and maintaining their own systems.Keywords: Software size, function points, valuation

APLICACIÓN DE MARCOS DE TRABAJO ÁGIL PARA EL DESARROLLO DE SOFTWARE EN AMBIENTES ACADÉMICOS

ResumenDentro de las actividades formativas en el área de los sistemas computacionales e informática, está el desarrollo de habilidades de gestión de proyectos, en donde no solamente se busca que los estudiantes adquieran un dominio técnico, sino que sean capaces de gestionar proyectos complejos donde se involucren productos a desarrollar, plazos de entrega definidos, así como personas, los cuales deberán integrarse y coordinarse para desarrollar los proyectos adecuadamente. Una alternativa para la realización de estas actividades es la aplicación de marcos de trabajo ágiles y otras herramientas de uso común en las empresas de desarrollo de software, sin embargo, la situación escolar tiene características que dificultan la aplicación de las técnicas de manera pura, siendo necesario realizar ajustes que permitan a la vez vivir los procesos, pero sin demandar más de lo requerido de acuerdo a las características del ámbito académico. El contenido de este artículo presenta la experiencia recabada en más de dos años de aplicación de marcos de trabajo ágil en cursos relacionados con el desarrollo de proyectos, durante los cuales se han identificado y aplicado diferentes prácticas y ajustes a las técnicas, para lograr que los estudiantes cuenten con un dominio vivencial de esta forma de trabajo.Palabra(s) Clave: Aprendizaje significativo, Desarrollo de proyectos, Marcos ágiles, Scrum. APPLICATION OF AGILE FRAMEWORKS FOR SOFTWARE DEVELOPMENT IN ACADEMIC ENVIRONMENTSAbstractAmong the training activities in the area of computer systems and information technology, is the development of project management skills, where not only students are expected to acquire a technical mastery, but are able to manage complex projects where they are involved products to be developed, defined delivery times, as well people, which must be integrated and coordinated to develop projects properly. An alternative for the realization of these activities is the application of agile frameworks and other tools commonly used in software development companies, however, the school situation has characteristics that make it difficult to apply the techniques in a pure way, being It is necessary to make adjustments that allow both to live the processes, but without demanding more than what is required according to the characteristics of the academic environment. The content of this article presents the experience gained in more than two years of application of agile frameworks in courses related to the development of projects, during which different practices and adjustments to the techniques have been identified and applied, in order to ensure that students to have an experiential domain of this way of working.Keywords: Agile frameworks, Meaningful learning, Project development, Scrum

Early Sensorineural Hearing Loss in Ob/Ob Mouse, an Animal Model of Type 2 Diabetes

ObjectivesThere have been many studies on the relationship between diabetes mellitus and presbycusis. Microangiopathy and neuropathy that's caused by chronic hyperglycemia may lead to damage to the inner ear. Several clinical studies on humans and animal studies have been performed to investigate the association between diabetes and hearing loss, however, this relationship is still a matter of debate. We investigated the association of diabetes and sensorineural hearing loss in an animal model of type-2 diabetes and obesity (the ob/ob mouse [OM]).MethodsThe auditory brainstem response (ABR) thresholds were obtained in the OM and the wild type mice (C57BL/6J mice) up to 25 weeks after birth. After the animals were sacrificed, their cochleae were retrieved and then subjected to histopathologic observations.ResultsThe OM exhibited significantly elevated ABR thresholds at 21 weeks of age, yet the C57BL/6J mice exhibited no significant change until 25 weeks of age. On the histological findings, outer hair cell degeneration and loss of spiral ganglion cells were observed in the middle and basal turns of the OM. On the contrary, no degenerative change was observed until 25 weeks of age in the C57BL/6J mice.ConclusionThis study suggests that chronic hyperglycemia and obesity may lead to early sensorineural hearing loss

Are Optimal Day-Ahead Markets Able to Face RES Uncertainty?: Evaluating Perfect Stochastic Energy Planning Models

Approximations made in day-ahead markets can result in suboptimal or even infeasible schedules for generating units and inaccurate predictions of actual costs and wind curtailment. Here we compare different optimal models of day-ahead markets based on unit commitment (UC) formulations, especially energy- vs. power-based UC; excluding or including startup and shutdown trajectories; and deterministic vs. “ideal” stochastic models to face wind uncertainty. The day-ahead hourly schedules are then evaluated against actual wind and load profiles using a (5-min) real-time dispatch model. We find that each simplification usually causes expected generation costs to increase by several percentage points, and results in significant understatement of expected wind curtailment and, in some cases, load interruption