Many agricultural fields that have received long-term applications of P often contain levels of P exceeding those required for optimal crop production. Knowledge of the effect of the P remaining in the soil (residual effect) is of great importance for fertilization management. In order to characterize P forms in soils, a wide variety of methods have been proposed. The use of dialysis membrane tubes filled with hydrous ferric oxide (DMT-HFO) has recently been reported as an effective way to characterize P desorption over a long-term in laboratoty studies. However, there is little information on the relationship between kinetics of P release using this new method and plant P uptake. This method consist of a procedure of shaking a sample for a long period of time there by exploiting the whole volume of the soil which is in contrast to the actual plant mode of uptake. This method has also practical limitations in employing it for a routine soil analysis, as it is very expensive and time consuming. The objectives of this study were (i) to study the changes in labile, non-labile and residual P using successive P desorption by DMT-HFO followed by a subsequent fractionation method (combined method) (ii) to assess how the information gained from P desorption kinetic data relates to plant growth at green house and field trials (iii) to investigate the effect of varying shaking time on DMT-HFO extractable P and (iv) to propose a short cut approach to the combined method. The release kinetics of the plots from long term fertilizer trials at the University of Pretoria and Ermelo were studied. P desorption kinetics were described relatively well by a two-component first-order model (R2 = 0.947, 0.918,&0.993 for NPK, MNK,&MNPK treatments respectively). The relative contributions of both the labile pool (SPA) and the less labile pool (SPB) to the total P extracted increased with increased P supply levels. Significant correlations were observed between the rate coefficients and maize grain yield for both soil types. The correlation between the cumulative P extracted and maize yield (r = 0.997**) however was highly significant for Ermelo soils. This method was also used to determine the changes in the different P pools and to relate these P fractions with maize yield. Highly significant correlations were observed between maize grain yield and the different P fractions including total P. In both soil types the contribution of both the labile and non-labile inorganic P fractions in replenishing the solution Pi was significant where as the contributions from the organic fractions were limited. The C/HCl-Pi is the fraction that decreased most in both cases as well. Investigation was carried out to evaluate the effect of varying shaking periods on the extractable DMT-HFO-Pi for UP soils of varying P levels. Four shaking options were applied. Significant difference was observed for the treatment of high P application. Shaking option 2 seemed relatively better than the others since it showed the strongest correlation. Thus for soils with high releasing kinetics and high total P content, provided that the P release from the soil is a rate limiting step, reducing the length of shaking time could shorten the duration one needs to complete the experiment with out influencing the predicting capacity of the methodology. The other objective of this thesis was also to present a short cut method alternative to the combined fractionation method. Comparison of the sum of DMT-HFO-Pi, NaHCO3-Pi, NaOH-Pi, D/HCl-Pi and C/HCl-Pi extracted by a conventional step-by-step method with the sum of DMT-HFO-Pi and a single C/HCl-Pi extraction as a short cut approach for all extraction periods resulted in strong and significant correlations. The C/HCl-Pi fraction extracted by both methods was correlated with maize grain yield and it was found to be highly significant. This study revealed that this short cut approach could be a simplified and economically viable option to study the P dynamics of soils especially for soils where the P pool acting as a source in replenishing the labile portion of P is already identified. The method employed here therefore could act as an analytical tool to approximate successive cropping experiments carried out under green house or field condition. However, data from a wider range of soils is needed to evaluate the universality of this method. More work is also required in relating desorption indices of this method with yield parameters especially at field level. / Thesis (PhD)--University of Pretoria, 2009. / Plant Production and Soil Science / PhD / unrestricted

Graphs are used to model a wide range of systems from different disciplines including social network analysis, biology, and big data processing. When analyzing these constantly changing dynamic graphs at a high frequency, performance is the main concern. Depending on the graph size and structure, update frequency, and read accesses of the analysis, the use of different data structures can yield great performance variations. Even for expert programmers, it is not always obvious, which data structure is the best choice for a given scenario. In previous work, we presented an approach for handling the selection of the most efficient data structures automatically using a compile-time approach well-suited for constant workloads. We extend this work with a measurement study of seven data structures and use the results to fit actual cost estimation functions. In addition, we evaluate our approach for the computations of seven different graph metrics. In analyses of real-world dynamic graphs with a constant workload, our approach achieves a speedup of up to 5.4× compared to basic data structure configurations. Such a compile-time based approach cannot yield optimal results when the behavior of the system changes later and the workload becomes non-constant. To close this gap we present a run-time approach which provides live profiling and facilitates automatic exchanges of data structures during execution. We analyze the performance of this approach using an artificial, non-constant workload where our approach achieves speedups of up to 7.3× compared to basic configurations.

El presente trabajo de investigación se realizó sobre la base de proceso de monitoreo de pacientes con alzhéimer. Para ello, se recopilaron diversas fuentes como testimonios de pacientes y familiares que permitieron identificar las tareas recurrentes en este proceso y los recursos asociados. En el análisis del proceso de monitoreo, se identificó problemas relacionados a los tiempos y costos que se generan. Asimismo, se identificó los signos vitales del paciente que son monitoreados con mayor frecuencia y las personas que intervienen en el monitoreo, los cuales son: cuidador y médico. Por otra parte, se realizo una investigación de las tecnologías que se usan actualmente para el monitoreo. En dichos estudios se establecen los mecanismos de supervisión del paciente; sin embargo, estos no brindan la información suficiente sobre el estado de salud del paciente. Después del análisis del proceso de monitoreo, se realizó una investigación adicional para determinar qué tipo de tecnologías permitiría optimizar este proceso. Asimismo, se definieron las variables de medición para identificar el impacto de la tecnología usada. Con la finalidad de obtener un resultado certero, se recurrió a cuidadores y médicos para saber la percepción respecto a la propuesta. / The present research work was carried out on the basis of the monitoring process of patients with Alzheimer's. For this, various sources were compiled such as testimonies from patients and relatives that made it possible to identify the recurring tasks in this process and the associated resources. In the analysis of the monitoring process, problems related to the times and costs generated were identified. Likewise, the vital signs of the patient that are monitored more frequently and the people involved in the monitoring were identified, which are: caregiver and doctor. On the other hand, an investigation of the technologies that are currently used for monitoring was carried out. In these studies, the mechanisms for patient supervision are established; however, these do not provide sufficient information on the patient's health status. After analyzing the monitoring process, additional research was conducted to determine what type of technologies would allow this process to be optimized. Likewise, the measurement variables were defined to identify the impact of the technology used. In order to obtain an accurate result, a survey was conducted with caregivers and doctors to find out their perception of the proposal. / Trabajo de investigación

En el Perú, el tiempo de espera para la consulta en las instituciones de salud está limitado por el número de recursos médicos y sus franjas horarias disponibles. Investigaciones recientes han demostrado que los sistemas en línea basados en la programación de citas médicas ayudan a los centros médicos a reducir el tiempo de espera de los pacientes para recibir atención médica. La presente investigación tiene como objetivo analizar y comparar sistemas de reserva de citas médicas, tomando en cuenta sus ventajas, características y funcionalidades que ayuden en la optimización de tiempo de espera para la atención médica y mejoren la calidad de la atención a los usuarios. Asimismo, se analizará las plataformas Cloud y herramientas multiplataforma que ayudarán en el desarrollo de la solución tecnológica. / In Peru, waiting time for medical appointments at healthcare facilities is limited by the number of medical resources and their available time slots. Recent studies have shown that online systems based on medical appointment scheduling help medical centers to reduce patients' waiting time for medical healthcare. The present research aims to analyze and compare medical appointment scheduling systems, considering their advantages, features and functionalities that help in the optimization of waiting time for medical care and improve the quality of care to users. Likewise, Cloud platforms and cross-platform development tools that will help in the development of the technological solution will be analyzed. / Trabajo de investigación

No description available.

I industriföretag används managementverktyg för att utveckla och effektivisera verksamheten så att ledtider och slöseri reduceras i samtliga processer. Parker PMDE Trollhättan tillverkar hydraulikmaskiner. Sedan 90-talet har Parker bedrivit verksamhetsutveckling enligt management principer i Lean Production. Ett nästa steg i Parkers ständiga förbättringsarbete var att undersöka möjligheter att utveckla en materialsatsningsavdelning så att en person kan förse monteringen med material tillräckligt snabbt utan att extra resurser behöver tillsättas. I dagsläget råder det obalans gentemot takttider i monteringen och det tar längre tid för satsningen att plocka ihop fyra satser än vad det tar för monteringen att förbruka dessa satser.Målet med examensarbetet var att ta fram förbättringsförslag där en person får förutsättningar att plocka ihop material till montering av fyra hydraulikmaskiner på mindre än 16 minuter. Delmålen var att göra en kartläggning av tider och arbetsmoment vid satsningen. Avgränsningarna i projektet var att inte undersöka processer utanför satsningen. Examensarbetet utformades efter DMAIC-metodiken, som är en projektmodell för faktabaserad problemlösning och tydlig struktur. Metoderna som användes vid insamling av data var observationer och analys av videoinspelat material som utfördes i programvaran AviX Method. Videoinspelningarna kategoriserades som olika aktiviteter i satsningsprocessen där gång, plock, scannertid, förmontering och övrig tid var de största kategorierna. Arbetsmoment identifierades som var tidskrävande och ej tillförde värde i processen. Mätningarna låg till grund för generering av lösningsförslagen.Baserat på ovanstående resultat och med hjälp av brainstorming genererades lösningsförslag tillsammans med produktionstekniker och materialhanterare. De lösningsförslag som uppfyllde målet med projektet att plocka en 4-sats under 16 minuter var pick by voice, pick by light, ringscanner och flytt av kilpress. Pick by voice anses vara lösningen som företaget bör införa eftersom den reducerar plocktid, scannertid och är ett flexibelt system. Ytterligare två lösningsförslag togs fram som inte uppfyllde målet men uppfattas som värda för företaget att utreda vidare utifrån Lean Production och ergonomiska skäl. De lösningsförslagen som inte uppfyllde målen bestod av en förändring av plockrundan och införande av en magnetlyft. / In industries, the management tools of Lean Production are used to develop and streamline operations in a way to reduce waste and lead times in all processes. Parker PMDE in Trollhättan manufactures hydraulic machines. Since the 90´s, Parker has pursued business development under the management principles of Lean Production. One of the next steps in Parkers continuous improvement was to explore opportunities to develop a kitting department so that a worker could provide the assembly with the material quickly without surplus resources. In the current situation, there is an imbalance from the kitting station towards the tact times in the assembly station because it takes longer at the kitting station to pick materials for four hydraulic machines, than it takes for the assembly station to consume these kits of materials.The aim of the thesis was to develop suggestions for improvement where a worker could perform the kitting process in less than 16 minutes. The interim objectives were to do a survey of the times and activities within the kitting process. The boundaries of the project was not to examine processes outside the kitting station. The project was designed according to DMAIC methodology, which is a project model for fact-based problem solving and clear structure. The methods used in the data collection were observation and analysis of video footage applying the software called AviX Method. Video recordings were categorized as different activities in the kitting process such as transport, picking, scanner time, pre-assembly and uncategorized time. Activities that were time consuming and did not add value to the process were identified. These data measures were the basis for the solution proposals.Based on these results and using brainstorming, solution proposals were generated together with the engineers and material handlers. The solution proposals that met the objective of the project of picking a 4-set of materials in 16 minutes were: Pick by voice, Pick-by-light, Ring Scanner and Relocation of one pre-assembly operation. Pick by voice is considered to be the most appropriate solution for the company since it reduces picking times, scanning times and is a flexible system. Two more proposed solutions were developed that did not meet the objective of the project, but are considered worth investigating further based on Lean Production and ergonomic reasons. These proposed solutions consisted of changing the picking route and the installation of a magnetic lift.

D'une manière schématique, l'optimisation dynamique de procédés consiste en trois étapes de base : (i) la modélisation, dans laquelle un modèle (phénoménologique) du procédé est construit, (ii) la formulation du problème, dans laquelle le critère de performance, les contraintes et les variables de décision sont définis, (iii) et la résolution, dans laquelle les profils optimaux des variables de décision sont déterminés. Il est important de souligner que ces profils optimaux garantissent l'optimalité pour le modèle mathématique utilisé. Lorsqu'ils sont appliqués au procédé, ces profils ne sont optimaux que lorsque le modèle décrit parfaitement le comportement du procédé, ce qui est très rarement le cas dans la pratique. En effet, les incertitudes sur les paramètres du modèle, les perturbations du procédé, et les erreurs structurelles du modèle font que les profils optimaux des variables de décision basés sur le modèle ne seront probablement pas optimaux pour le procédé. L'application de ces profils au procédé conduit généralement à la violation de certaines contraintes et/ou à des performances sous-optimales. Pour faire face à ces problèmes, l'optimisation dynamique en temps-réel constitue une approche tout à fait intéressante. L'idée générale de cette approche est d'utiliser les mesures expérimentales associées au modèle du procédé pour améliorer les profils des variables de décision de sorte que les conditions d'optimalité soient vérifiées sur le procédé (maximisation des performances et satisfaction des contraintes). En effet, pour un problème d'optimisation sous contraintes, les conditions d'optimalité possèdent deux parties : la faisabilité et la sensibilité. Ces deux parties nécessitent différents types de mesures expérimentales, à savoir les valeurs du critère et des contraintes, et les gradients du critère et des contraintes par rapport aux variables de décision. L'objectif de cette thèse est de développer une stratégie conceptuelle d'utilisation de ces mesures expérimentales en ligne de sorte que le procédé vérifie non seulement les conditions nécessaires, mais également les conditions suffisantes d'optimalité. Ce développement conceptuel va notamment s'appuyer sur les récents progrès en optimisation déterministe (les méthodes stochastiques ne seront pas abordées dans ce travail) de procédés basés principalement sur l'estimation des variables d'état non mesurées à l'aide d'un observateur à horizon glissant. Une méthodologie d'optimisation dynamique en temps réel (D-RTO) a été développée et appliquée à un réacteur batch dans lequel une réaction de polymérisation par greffage a lieu. L'objectif est de déterminer le profil temporel de température du réacteur qui minimise le temps opératoire tout en respectant des contraintes terminales sur le taux de conversion et l'efficacité de greffage / In a schematic way, process optimization consists of three basic steps: (i) modeling, in which a (phenomenological) model of the process is developed, (ii) problem formulation, in which the criterion of Performance, constraints and decision variables are defined, (iii) the resolution of the optimal problem, in which the optimal profiles of the decision variables are determined. It is important to emphasize that these optimal profiles guarantee the optimality for the model used. When applied to the process, these profiles are optimal only when the model perfectly describes the behavior of the process, which is very rarely the case in practice. Indeed, uncertainties about model parameters, process disturbances, and structural model errors mean that the optimal profiles of the model-based decision variables will probably not be optimal for the process. The objective of this thesis is to develop a conceptual strategy for using experimental measurements online so that the process not only satisfies the necessary conditions, but also the optimal conditions. This conceptual development will in particular be based on recent advances in deterministic optimization (the stochastic methods will not be dealt with in this work) of processes based on the estimation of the state variables that are not measured by a moving horizon observer. A dynamic real-time optimization (D-RTO) methodology has been developed and applied to a batch reactor where polymer grafting reactions take place. The objective is to determine the on-line reactor temperature profile that minimizes the batch time while meeting terminal constraints on the overall conversion rate and grafting efficiency

Graphs are used to model a wide range of systems from different disciplines including social network analysis, biology, and big data processing. When analyzing these constantly changing dynamic graphs at a high frequency, performance is the main concern. Depending on the graph size and structure, update frequency, and read accesses of the analysis, the use of different data structures can yield great performance variations. Even for expert programmers, it is not always obvious, which data structure is the best choice for a given scenario. In previous work, we presented an approach for handling the selection of the most efficient data structures automatically using a compile-time approach well-suited for constant workloads. We extend this work with a measurement study of seven data structures and use the results to fit actual cost estimation functions. In addition, we evaluate our approach for the computations of seven different graph metrics. In analyses of real-world dynamic graphs with a constant workload, our approach achieves a speedup of up to 5.4× compared to basic data structure configurations. Such a compile-time based approach cannot yield optimal results when the behavior of the system changes later and the workload becomes non-constant. To close this gap we present a run-time approach which provides live profiling and facilitates automatic exchanges of data structures during execution. We analyze the performance of this approach using an artificial, non-constant workload where our approach achieves speedups of up to 7.3× compared to basic configurations.

<div>Optimization of atmospheric flight control has long been performed on the ground, prior to mission flight due to large computational requirements used to solve non-linear programming problems. Onboard trajectory optimization enables the creation of new reference trajectories and updates to guidance coefficients in real time. This thesis summarizes the methods involved in solving optimal control problems in real time using convexification and Sequential Convex Programming (SCP). The following investigation provided insight in assessing the use of state of the art SCP optimization architectures and convexification of the hypersonic equations of motion[ 1 ]–[ 3 ] with different control schemes for the purposes of enabling on-board trajectory optimization capabilities.</div><div>An architecture was constructed to solve convexified optimal control problems using direct population of sparse matrices in triplet form and an embedded conic solver to enable rapid turn around of optimized trajectories. The results of this show that convexified optimal control problems can be solved quickly and efficiently which holds promise in autonomous trajectory design to better overcome unexpected environments and mission parameter changes. It was observed that angle of attack control problems can be successfully convexified and solved using SCP methods. However, the use of multiple coupled controls is not guaranteed to be successful with this method when they act in the same plane as one another. The results of this thesis demonstrate that state of the art SCP methods have the capacity to enable onboard trajectory optimization with both angle of attack control and bank angle control schemes.</div><div><br></div>

En Lima, la construcción de edificios multifamiliares está creciendo de forma exponencial y muchas constructoras tienen problemas para cumplir con el plazo establecido. Además, los proyectos de edificios multifamiliares cuentan con un alto número de partidas, en la cual se necesita mano de obra especializada por lo que las empresas subcontratan algunas actividades. Para esto, es necesario llevar un control de avance en la etapa de ejecución, de tal manera que la constructora pueda manejar de forma óptima, rápida y sencilla el avance de las diversas especialidades. La propuesta busca optimizar el tiempo de ejecución en edificios multifamiliares de nivel socioeconómico A y B ubicados en Lima top y Lima moderna en base al control de avance de las subcontratas utilizando herramientas tecnológicas en la etapa de acabados. En este sentido, la presente investigación desarrolla una propuesta consistente en la que se utiliza la aplicación Plan Grid para la recolección de información en obra, el software Power Bi para el procesamiento automático de la data y la visualización de un tablero de control que contiene indicadores y gráficos que reflejen el avance y rendimiento real de las partidas ejecutas, así como las principales causas de incumplimiento. La propuesta queda plasmada en una guía para el control de avance de subcontratistas y oriente a la correcta implementación. Con esto, se pueden tomar mejores decisiones y de tal manera, decidir rápidas y eficientes acciones correctivas y preventivas en base al tablero de control de avance. / In Lima, the construction of residential buildings is growing exponentially, and many construction companies are having problems meeting the established deadline. In addition, residential building projects have a high number of items, in which specialized labor is needed, which is why companies subcontract some activities. For this, it is necessary to keep track of progress in the execution stage, in such a way that the construction company can optimally, quickly and easily handle the progress of the different specialties. The proposal seeks to optimize the execution time in residential buildings of socioeconomic level A and B located in Lima top and Lima modern based on the progress control of subcontractors using technological tools in the architecture stage. In this sense, this research develops a consistent proposal in which the Plan Grid application is used to collect information on site, the Power Bi software for automatic data processing and the visualization of a dashboard that contains indicators and graphs that reflect the progress and the real performance of the executed activities, as well as the main causes of non-fulfillment. The proposal is reflected in a guide for the control progress of subcontractors and directs to the correct implementation. With this, better decisions can be made and in such a way, decide fast and efficient corrective and preventive actions based on the progress control dashboard. / Tesis