Modelling indoor air carbon dioxide concentration using grey-box models

Predictive control is the strategy that has the greatest reported benefits when it is implemented in a building energy management system. Predictive control requires low-order models to assess different scenarios and determine which strategy should be implemented to achieve a good compromise between comfort, energy consumption and energy cost. Usually, a deterministic approach is used to create low-order models to estimate the indoor CO2 concentration using the differential equation of the tracer-gas mass balance. However, the use of stochastic differential equations based on the tracer-gas mass balance is not common. The objective of this paper is to assess the potential of creating predictive models for a specific room using for the first time a stochastic grey-box modelling approach to estimate future CO2 concentrations. First of all, a set of stochastic differential equations are defined. Then, the model parameters are estimated using a maximum likelihood method. Different models are defined, and tested using a set of statistical methods. The approach used combines physical knowledge and information embedded in the monitored data to identify a suitable parametrization for a simple model that is more accurate than commonly used deterministic approaches. As a consequence, predictive control can be easily implemented in energy management systems.Peer ReviewedPostprint (author's final draft

Facility managers’ perceptions on building performance assessment

During the operational phase, building performance may decrease in various areas, so that the end users’ requirements are no longer met. Consequently, indicators are useful to assessand improve the performance of existing buildings. In this study, we carried out a literature review and organized a focus group with facility management experts to gather and analyze facility managers’ perceptions on operational indicators that could be used to assess the performance of buildings. The results revealed that the core indicators used to measure a building’s operational performance are related to safety and assets working properly, health and comfort, space functionality, and energy performance. The findings also revealed that these indicators can be obtained from three sources: a) facility managers/operators, who carry out corrective maintenance and perform technical inspections, b) regular users, who report complaints and fill-in satisfaction questionnaires, and c) sporadic users, who also fill-in satisfaction questionnaires. These indicators and their sources can contribute to a better analysis of building performance and the definition of measures to improve performance during the operational phase of a building.Peer ReviewedPostprint (published version

The El Sitio cultural project

Centro para jóvenes artistas plásticos y de las artes escénicas con el objetivo de difundir la cultura y las artes además de estimular la participación de las personas en la vida comunitaria y la capacitación en expresión artística para niños y jóvenes

La justícia i la mesura. Pensar la justícia i la injustícia. a partir de Simone Weil i Plató

El present article analitza els conceptes de justícia i injustícia a partir de les obres de Simone Weil i Plató. Definides a partir de la seva relació amb altres conceptes com els de mesura, proporció o límit, la justícia, d'una banda, se'ns apareix com un bé per l'ànima d'aquella persona que la practica, atès que permet la llibertat; la injustícia, de l'altra, com un mal en ella mateixa, perquè implica l'esclavatge de les persones injustes. L'article pretén també mostrar que aquesta conceptualització de la justícia i la injustícia proporciona eines teòriques que poden ser útils per analitzar la societat actual

Factors affecting rework costs in construction

Rework adversely impacts the performance of building projects. In this study, data were analyzed from 788 construction incidents in 40 Spanish building projects to determine the influence of project and managerial characteristics on rework costs. Finally, regression analysis was used to understand the relationship between the contributing factors, and to determine a model for rework prediction.Interestingly, the rework prediction model showed that only the original contract value (OCV) and the project location in relation to the company’s headquarters contribute to the regression model. The Project type, the Type of organization, the Type of contract and the original contract duration (OCD) which represents the magnitude and complexity of a project, were represented by the OCV. This model for rework prediction based on original project conditions enables strategies to be put in place prior to the start of construction, to minimize uncertainties and reduce the impact on project cost and schedule, and thus improve productivity.Peer ReviewedPostprint (author's final draft

Ralstonia solanacearum, a widespread bacterial plant pathogen in the post-genomic era

Ralstonia solanacearum is a soil-borne bacterium causing the widespread disease known as bacterial wilt. Ralstonia solanacearum is also the causal agent of Moko disease of banana and brown rot of potato. Since the last R. solanacearum pathogen profile was published 10 years ago, studies concerning this plant pathogen have taken a genomic and post-genomic direction. This was pioneered by the first sequenced and annotated genome for a major plant bacterial pathogen and followed by many more genomes in subsequent years. All molecular features studied now have a genomic flavour. In the future, this will help in connecting the classical field of pathology and diversity studies with the gene content of specific strains. In this review, we summarize the recent research on this bacterial pathogen, including strain classification, host range, pathogenicity determinants, regulation of virulence genes, type III effector repertoire, effector-triggered immunity, plant signalling in response to R. solanacearum, as well as a review of different new pathosystems