SQualTrack: A Tool for Robust Fault Detection

One of the techniques used to detect faults in dynamic systems is analytical redundancy. An important difficulty in applying this technique to real systems is dealing with the uncertainties associated with the system itself and with the measurements. In this paper, this uncertainty is taken into account by the use of intervals for the parameters of the model and for the measurements. The method that is proposed in this paper checks the consistency between the system's behavior, obtained from the measurements, and the model's behavior; if they are inconsistent, then there is a fault. The problem of detecting faults is stated as a quantified real constraint satisfaction problem, which can be solved using the modal interval analysis (MIA). MIA is used because it provides powerful tools to extend the calculations over real functions to intervals. To improve the results of the detection of the faults, the simultaneous use of several sliding time windows is proposed. The result of implementing this method is semiqualitative tracking (SQualTrack), a fault-detection tool that is robust in the sense that it does not generate false alarms, i.e., if there are false alarms, they indicate either that the interval model does not represent the system adequately or that the interval measurements do not represent the true values of the variables adequately. SQualTrack is currently being used to detect faults in real processes. Some of these applications using real data have been developed within the European project advanced decision support system for chemical/petrochemical manufacturing processes and are also described in this paper

Modelización bajo el enfoque de dinámica de sistemas de una cadena de abastecimiento para la industria vitivinícola

El proyecto de tesis denominado “Modelización bajo el enfoque de dinámica de sistemas de una cadena de abastecimiento para la industria vitivinícola” busca construir un modelo que aporte una solución óptima al problema logístico encontrado en la cadena de suministro, para que empresas nacionales o internacionales que tengan un funcionamiento similar al del sistema estudiado, puedan tomarlo como ejemplo o referencia. Así mismo, esta investigación pretende encontrar los problemas más frecuentes en cadenas de este tipo con el fin de construir un marco conceptual y teórico fundamentado en la Teoría General de Sistemas (TGS) que genere finalmente un modelo basado en la dinámica de sistemas el cual permitirá a las empresas diseñar y comparar las diferentes intervenciones derivadas del modelo que propicien la generación de capacidades dirigidas al logro de la competitividad de forma perdurable.

Desenlaces clínicos del cuidado perioperatorio de reemplazos articulares según grupos relacionados de diagnóstico en un hospital de cuarto nivel

Introducción Los Grupos Relacionados de Diagnóstico (GRD) se han usado para determinar la calidad de la atención en varios sistemas de salud. Esto ha llevado a que se obtengan resultados en el mejoramiento continuo de la atención y del cuidado. El objetivo de este estudio es determinar desenlaces clínicos de los pacientes a quienes se les había realizado reemplazo de articulares según la complejidad clínica definida mediante GRD. Métodos Se realizó un estudio longitudinal descriptivo en el cual se incluyeron todos los pacientes que tuvieron cirugía de reemplazo total de hombro, cadera y rodilla entre 2012 y 2014. Se realizó la estratificación de los pacientes de acuerdo a tres niveles de complejidad dados por el sistema de GRD y se determinaron las proporciones de pacientes para las variables de estancia hospitalaria, enfermedad trombo-embólica, cardiovascular e infección del sitio operatorio. Resultados Se realizaron en total 886 reemplazos articulares de los cuales 40 (4.5%) presentaron complicaciones. Los eventos más frecuentes fueron las complicaciones coronarias, con una presencia de 2.4%. El GRD1, sin complicaciones ni comorbilidades, fue el que presentó mayor número de eventos. La estancia hospitalaria fue de 3.8 a 9.3 días para todos los reemplazos. Conclusiones Contrario a lo planteado en la hipótesis de estudio, se encontró que el primer GRD presentó el mayor número de complicaciones, lo que puede estar relacionado con el tamaño del grupo. Es necesario realizar nuevas investigaciones que soporten el uso de los GRD como herramienta para evaluar desenlaces clínicos.

Desenvolupament d'un sistema expert com a eina per a una millor gestió de la qualitat de les aigües fluvials

Avui en dia no es pot negar el fet que els humans són un component més de les conques fluvials i que la seva activitat afecta enormement la qualitat de les aigües. A nivell europeu, l'elevada densitat de població situada en les conques fluvials ha comportat un increment de la mala qualitat de les seves aigües fluvials. En les darreres dècades l'increment de les càrregues de nutrients en els sistemes aquàtics ha esdevingut un problema prioritari a solucionar per les administracions competents en matèria d'aigua. La gestió dels ecosistemes fluvials no és una tasca fàcil. Els gestors es troben amb què són sistemes molt complexos, donada l'estreta relació existent entre els ecosistemes fluvials i els ecosistemes terrestres que drenen. Addicionalment a la complexitat d'aquests sistemes es troba la dificultat associada de la gestió o control de les entrades de substàncies contaminants tant de fonts puntuals com difoses. Per totes aquestes raons la gestió de la qualitat de les aigües fluvials esdevé una tasca complexa que requereix un enfocament multidisciplinar. Per tal d'assolir aquest enfocament diverses eines han estat utilitzades, des de models matemàtics fins a sistemes experts i sistemes de suport a la decisió. Però, la major part dels esforços han estat encarats cap a la resolució de problemes de reduïda complexitat, fent que molts dels problemes ambientals complexos, com ara la gestió dels ecosistemes fluvials, no hagin estat vertaderament tractats. Per tant, es requereix l'aplicació d'eines que siguin de gran ajuda en els processos de presa de decisions i que incorporin un ampli coneixement heurístic i empíric: sistemes experts i sistemes de suport a la decisió. L'òptima gestió de la qualitat de l'aigua fluvial requereix una aproximació integrada i multidisciplinar, que pot ésser aconseguida amb una eina intel·ligent construïda sobre els conceptes i mètodes del raonament humà. La present tesi descriu la metodologia desenvolupada i aplicada per a la creació i construcció d'un Sistema Expert, així com el procés de desenvolupament d'aquest Sistema Expert, com el principal mòdul de raonament d'un Sistema de Suport a la Decisió Ambiental. L'objectiu principal de la present tesi ha estat el desenvolupament d'una eina d'ajuda en el procés de presa de decisions dels gestors de l'aigua en la gestió de trams fluvials alterats antròpicament per tal de millorar la qualitat de la seva aigua fluvial. Alhora, es mostra el funcionament de l'eina desenvolupada a través de dos casos d'estudi. Els resultats derivats del Sistema Expert desenvolupat, implementat i presentat en la present tesi mostren que aquests sistemes poden ésser eines útils per a millorar la gestió dels ecosistemes fluvials.

Optimització del procés productiu d'engreixament porcí. Un enfocament operatiu

Aquest treball de tesis doctoral tracta de la Optimització de la fase d'engreix. L'objectiu és determinar les condicions d'enviament a sacrifici d'un lot d'animals des d'un punt de vista operatiu. En primer lloc es fa una anàlisi de la cadena de producció de carn porcina, resaltant-ne els canvis del sector que han influit en la fase d'engreixament. La conclusió d'aquesta anàlisi és el plantejament d'un model per prendre decisions degut al canvi de paradigma que s'evidencia: els productors de porcs en la fase d'engreix cal que orientin la gestió del paràmetres operatius i els productes finals a les exigències i gustos dels seus clients. Seguidament, es presenta el sistema d'ajut a la decisió basat en un model biològic que explica l'evolució de les variables productives (pes i consum de pinso). A més també prediu les variables associades a característiques de la canal, com són el percentatge de magre, la proporció de peces, el rendiment i el greix intramuscular. El sistema té en compte tres mercats de carn porcina alternatius: 1) basat en pes viu, 2) basat en mèrits de la canal (percentatge de magre) y 3) basat en el valor de les peces nobles resultants de l'especejament de l'animal. L'objetiu del sistema és determinar la millor estratègia d'enviament per a cadascun dels genotips que s'han estudiat (alternatives de producció) depenent del mercat on seran enviats els animals. A més, també ha estat estudiat l'efecte de la variabilitat biològica dels animals dins del lot sobre els valors econòmics. També s'ha considerat l'opció d'enviar els animals en diverses etapes per tal d'homogeneitzar el pes dels animals enviats. Aquest problema ha estat estudiat seguint l'enfocament de programació dinàmica. En els darrers capítols es presenten quatre aplicacions del model que s'han desenvolupat al llarg del treball. En un futur els mercats de carn porcina tindran la tendència a ser més definits, per tant la producció en la fase d'engreixament porcí hauria d'integrar i tenir en compte les demandes i les exigències del consumidor.

Desenvolupament d'un sistema de suport a la decisió ambiental per a la gestió de les infraestructures hidràuliques, amb l'objectiu de garantir la qualitat de l'aigua a la Conca del Besòs

Aquesta tesi presenta un projecte de gestió integral d'infraestructures hidràuliques de sanejament a la Conca del riu Besòs. S'han considerat dos sistemes de sanejament (La Garriga i Granollers) amb les seves respectives xarxes de clavegueram i Estacions Depuradores d'Aigües Residuals (EDAR), i un tram del riu Congost, afluent del Besòs, com a medi receptor de les seves aigües residuals. Amb aquesta finalitat es construeix i s'utilitza un Sistema de Suport a la Decisió Ambiental (SSDA). Aquesta eina incorpora l'ús de models de simulació de qualitat de l'aigua pels sistemes de clavegueram, EDAR i riu, com a forma d'extracció de coneixement sobre la gestió integrada d'aquests elements. Aquest coneixement es conceptualitza, posteriorment, en forma d'arbres de decisió, que proporcionaran a l'usuari les actuacions a realitzar davant de les diferents situacions reals de gestió diària.

Supporting multi-organisational collaborative groups in the public sector

In this paper, the issues that arise in multi-organisational collaborative groups (MOCGs) in the public sector are discussed and how a technology-based group support system (GSS) could assist individuals within these groups. MOCGs are commonly used in the public sector to find solutions to multifaceted social problems. Finding solutions for such problems is difficult because their scope is outside the boundary of a single government agency. The standard approach to solving such problems is collaborative involving a diverse range of stakeholders. Collaborative working can be advantageous but it also introduces its own pressures. Conflicts can arise due to the multiple contexts and goals of group members and the organisations that they represent. Trust, communication and a shared interface are crucial to making any significant progress. A GSS could support these elements.

Mitigation of diffuse phosphorus pollution during rewetting of fen peat soils: A trans-European case study

Intensive cultivation of fen peat soils (Eutric Histosols) for agricultural purposes, started in Europe about 250 years ago, resulting in decreased soil fertility, increased oxidation of peat and corresponding CO2-emissions to the atmosphere, nutrient transfer to aquatic ecosystems and losses in the total area of the former native wetlands. To prevent these negative environmental effects set-aside programs and rewetting measures were promoted in recent years. Literature results and practical experiences showed that large scale rewetting of intensively used agricultural Histosols may result in the mobilisation of phosphorus (P), its transport to adjacent surface waters and an accelerated eutrophication risk. The paper summarises results from an international European Community sponsored research project and demonstrates how results obtained at different scales and from different scientific disciplines were compiled to derive a strategy to carry out rewetting measures. A decision support system (DSS) for a hydrologically sensitive area in the Droemling catchment in north-eastern Germany was developed and is presented as a tool to regulate rewetting in order to control P release. It is demonstrated that additional laboratory experiments to identify essential processes of P release during rewetting and the site-specific management of the water table, the involvement of specific knowledge and experience of the stakeholders are necessary to develop an applicable DSS. The presented DSS is practically used to prevent freshwater resources from diffuse P pollution.

Drought, pod yield, pre-harvest Aspergillus infection and aflatoxin contamination on peanut in Niger

Soil moisture and soil temperature affect pre-harvest infection with Aspergillus flavus and production of aflatoxin. The objectives of our field research in Niger, West Africa, were to: (i) examine the effects of sowing date and irrigation treatments on pod yield, infection with A. flavus and aflatoxin concentration; and (ii) to quantify relations between infection, aflatoxin concentration and soil moisture stress. Seed of an aflatoxin susceptible peanut cv. JL24 was sown at two to four different sowing dates under four irrigation treatments (rainfed and irrigation at 7, 14 and 21 days intervals) between 1991 and 1994, giving 40 different 'environments'. Average air and soil temperatures of 28-34 degrees C were favourable for aflatoxin contamination. CROPGRO-peanut model was used to simulate the occurrence of moisture stress. The model was able to simulate yields of peanut well over the 40 environments (r(2) = 0.67). In general, early sowing produced greater pod yields, as well as less infection and lower aflatoxin concentration. There were negative linear relations between infection (r(2) = 0.62) and the average simulated fraction of extractable soil water (FESW) between flowering and harvest, and between aflatoxin concentration (r(2) = 0.54) and FESW in the last 25 days of pod-filling. This field study confirms that infection and aflatoxin concentration in peanut can be related to the occurrence of soil moisture stress during pod-filling when soil temperatures are near optimal for A. flavus. These relations could form the basis of a decision-support system to predict the risk of aflatoxin contamination in peanuts in similar environments. (c) 2005 Elsevier B.V. All rights reserved.

An integrated mathematical model to evaluate nutrient partition in dairy cattle between the animal and its environment

In the past decade, a number of mechanistic, dynamic simulation models of several components of the dairy production system have become available. However their use has been limited due to the detailed technical knowledge and special software required to run them, and the lack of compatibility between models in predicting various metabolic processes in the animal. The first objective of the current study was to integrate the dynamic models of [Brit. J. Nutr. 72 (1994) 679] on rumen function, [J. Anim. Sci. 79 (2001) 1584] on methane production, [J. Anim. Sci. 80 (2002) 2481 on N partition, and a new model of P partition. The second objective was to construct a decision support system to analyse nutrient partition between animal and environment. The integrated model combines key environmental pollutants such as N, P and methane within a nutrient-based feed evaluation system. The model was run under different scenarios and the sensitivity of various parameters analysed. A comparison of predictions from the integrated model with the original simulation models showed an improvement in N excretion since the integrated model uses the dynamic model of [Brit. J. Nutr. 72 (1994) 6791 to predict microbial N, which was not represented in detail in the original model. The integrated model can be used to investigate the degree to which production and environmental objectives are antagonistic, and it may help to explain and understand the complex mechanisms involved at the ruminal and metabolic levels. A part of the integrated model outputs were the forms of N and P in excreta and methane, which can be used as indices of environmental pollution. (C) 2004 Elsevier B.V All rights reserved.

Categorization and construction of rule based systems

Expert systems have been increasingly popular for commercial importance. A rule based system is a special type of an expert system, which consists of a set of ‘if-then‘ rules and can be applied as a decision support system in many areas such as healthcare, transportation and security. Rule based systems can be constructed based on both expert knowledge and data. This paper aims to introduce the theory of rule based systems especially on categorization and construction of such systems from a conceptual point of view. This paper also introduces rule based systems for classification tasks in detail.

Optimising mirid control on cocoa farms through complementary monitoring systems

Mirids (Sahlbergella singularis and Distantiella theobroma) are the most important insect pests affecting cocoa production across West Africa. Understanding the population dynamics of mirids is key to their management, however, the current recommended hand-height assessment method is labour intensive. The objective of the study was to compare recently developed mirid sex pheromone trapping and visual hand-height assessment methods as monitoring tools on cocoa farms and to consider implications for a decision support system. Ten farms from the Eastern and Ashanti regions of Ghana were used for the study. Mirid numbers and damage were assessed fortnightly on twenty trees per farm, using both methods, from January 2012 to April 2013. The mirid population increased rapidly in June, reached a peak in September and began to decline in October. There was a significant linear relationship between numbers of mirids sampled to hand-height and mirid damage. High numbers of male mirids were recorded in pheromone traps between January and April 2012 after which there was a gradual decline. There was a significant inverse relationship between numbers of trapped adult mirids and mirids sampled to hand-height (predominantly nymphs). Higher temperatures and lower relative humidities in the first half of the year were associated with fewer mirids at hand-height but larger numbers of adult males were caught in pheromone traps. The study showed that relying solely on one method is not sufficient to provide accurate information on mirid population dynamics and a combination of the two methods is necessary.

Knowledge based crime scenario modelling

A crucial concern in the evaluation of evidence related to a major crime is the formulation of sufficient alternative plausible scenarios that can explain the available evidence. However, software aimed at assisting human crime investigators by automatically constructing crime scenarios from evidence is difficult to develop because of the almost infinite variation of plausible crime scenarios. This paper introduces a novel knowledge driven methodology for crime scenario construction and it presents a decision support system based on it. The approach works by storing the component events of the scenarios instead of entire scenarios and by providing an algorithm that can instantiate and compose these component events into useful scenarios. The scenario composition approach is highly adaptable to unanticipated cases because it allows component events to match the case under investigation in many different ways. Given a description of the available evidence, it generates a network of plausible scenarios that can then be analysed to devise effective evidence collection strategies. The applicability of the ideas presented here are demonstrated by means of a realistic example and prototype decision support software.

Evaluating And Optimizing Sustainable Drainage Design To Maximize Multiple Benefits: Case Studies In China

In the past, the focus of drainage design was on sizing pipes and storages in order to provide sufficient network capacity. This traditional approach, together with computer software and technical guidance, had been successful for many years. However, due to rapid population growth and urbanisation, the requirements of a “good” drainage design have also changed significantly. In addition to water management, other aspects such as environmental impacts, amenity values and carbon footprint have to be considered during the design process. Going forward, we need to address the key sustainability issues carefully and practically. The key challenge of moving from simple objectives (e.g. capacity and costs) to complicated objectives (e.g. capacity, flood risk, environment, amenity etc) is the difficulty to strike a balance between various objectives and to justify potential benefits and compromises. In order to assist decision makers, we developed a new decision support system for drainage design. The system consists of two main components – a multi-criteria evaluation framework for drainage systems and a multi-objective optimisation tool. The evaluation framework is used for the quantification of performance, life-cycle costs and benefits of different drainage systems. The optimisation tool can search for feasible combinations of design parameters such as the sizes, order and type of drainage components that maximise multiple benefits. In this paper, we will discuss real-world application of the decision support system. A number of case studies have been developed based on recent drainage projects in China. We will use the case studies to illustrate how the evaluation framework highlights and compares the pros and cons of various design options. We will also discuss how the design parameters can be optimised based on the preferences of decision makers. The work described here is the output of an EngD project funded by EPSRC and XP Solutions.