Optimisation of racing car suspensions featuring inerters

Racing car suspensions are a critical system in the overall performance of the vehicle. They must be able to accurately control ride dynamics as well as influencing the handling characteristics of the vehicle and providing stability under the action of external forces. This work is a research study on the design and optimisation of high performance vehicle suspensions using inerters. The starting point is a theoretical investigation of the dynamics of a system fitted with an ideal inerter. This sets the foundation for developing a more complex and novel vehicle suspension model incorporating real inerters. The accuracy and predictability of this model has been assessed and validated against experimental data from 4- post rig testing. In order to maximise overall vehicle performance, a race car suspension must meet a large number of conflicting objectives. Hence, suspension design and optimisation is a complex task where a compromised solution among a set of objectives needs to be adopted. The first task in this process is to define a set of performance based objective functions. The approach taken was to relate the ride dynamic behaviour of the suspension to the overall performance of the race car. The second task of the optimisation process is to develop an efficient and robust optimisation methodology. To address this, a multi-stage optimisation algorithm has been developed. The algorithm is based on two stages, a hybrid surrogate model based multiobjective evolutionary algorithm to obtain a set of non-dominated optimal suspension solutions and a transient lap-time simulation tool to incorporate external factors to the decision process and provide a final optimal solution. A transient lap-time simulation tool has been developed. The minimum time manoeuvring problem has been defined as an Optimal Control problem. A novel solution method based on a multi-level algorithm and a closed-loop driver steering control has been proposed to find the optimal lap time. The results obtained suggest that performance gains can be obtained by incorporating inerters into the suspension system. The work suggests that the use of inerters provides the car with an optimised aerodynamic platform and the overall stability of the vehicle is improved

Patterns of care and outcome for patients with glioblastoma diagnosed during 2008-2010 in Spain

Seit einigen Jahren unterliegt der Bereich der Ingenieurgeodäsie einem starken Wandel, da sich diese Disziplin generell den stetig weiterentwickelnden, anwendungsbezogenen Problemstellungen widmet. Unter diesen Aspekten ist insbesondere die flächenhafte Erfassung von Objekten und ihrer Geometrien – bis hin zur ganzheitlichen Raumkontinuisierung – in den Fokus der Ingenieurgeodäsie geraten. In diesem Kontext ergründet diese Dissertation, inwieweit die Konfiguration bei der Approximation von Oberflächen, die räumlich ungleichmäßig abgetastet wurden, analysiert und gegebenenfalls auch optimiert werden kann. Die zugrunde liegenden Messungen basieren auf Nivellements und terrestrischen Laserscans. Deren Oberflächenabtastung ist jeweils ungleichmäßig. Bei Nivellements liegt die Ursache in der Wirtschaftlichkeit und Siedlungsstruktur der Untersuchungsgebiete, beim terrestrischen Laserscanning (TLS) kann dies messtechnisch mit der polaren Abtastung begründet werden. In beiden Fällen dienen die Messpunkte häufig zur Approximation von Oberflächen, um flächenkontinuierliche Aussagen treffen zu können. Gängige Anwendungen sind z.B. die Analyse von Bodenbewegungen beim Nivellement oder die Deformationsanalyse beim TLS. Obwohl bei diesen Anwendungen im Allgemeinen eine ausreichend große Anzahl an Messpunkten zur Verfügung steht, führt die ungleichmäßige Punktverteilung dennoch oftmals zu einer ungünstigen Konfiguration des Ausgleichs. Diese kann in Kombination mit dem oft nur limitiert vorhanden Modellwissen bei der Flächenmodellierung zu verzerrten Parameterschätzungen führen. Diese Konfiguration gilt es demnach zu analysieren und ggf. auch zu optimieren. Auf Basis dieser methodischen Analysen können schwerpunktmäßig vier Aspekte herausgestellt werden: 1) Anhand der Redundanzanteile sowie anhand von relativen Redundanzanteilunterschieden kann gezeigt werden, dass die ungleichmäßige Punktverteilung in Kombination mit limitiertem Modellwissen zu einer suboptimalen Konfiguration bei der Approximation von Oberflächen führt. Die Redundanzanteile vereinen sowohl die geometrische Verteilung der Messpunkte, die Objektgeometrie als auch das stochastische Modell der Beobachtungen zur Beurteilung der Zuverlässigkeit und der Konfiguration. 2) Zur Optimierung der Konfiguration bei der Approximation flächenhafter Nivellements wird ein Algorithmus aufgestellt, der die Messpunktverteilung im Bezug zur Komplexität der Bodensenkungen objektiv bewertet. Die existierenden Messpunkte werden hinsichtlich ihrer Wichtigkeit für die Approximation – auf Basis der Konfiguration – selektiert. Zusätzlich ist es in der Netzausgleichung erstmals möglich, die Positionen und die Anzahl zusätzlich benötigter Messpunkte zu bestimmen. 3) Die Approximationen gescannter Oberflächen sind oft verzerrt und abhängig vom Standpunkt. Dies kann anhand einer Konfigurationsanalyse unter Betrachtung der Redundanzanteile quantifiziert und analysiert werden. Ferner kann durch eine Punktausdünnung – also durch die Herstellung einer gleichmäßigen Abtastung – eine Minimierung der Standpunktabhängigkeit erzeugt werden. Dies zeigt sich auch in Form einer verbesserten Konfiguration. 4) Ein weiterentwickeltes Konzept zur scannerbasierten Deformationsuntersuchung integriert die beschriebenen Aspekte der Konfigurationsanalyse und -optimierung anhand eines konkreten Beispiels. Ferner wird der Aspekt der Scannerkalibrierung hervorgehoben und in die Deformationsanalyse integriert. Insgesamt bedeuten diese Maßnahmen einen großen Fortschritt für die Nutzung terrestrischer Laserscanner zur zuverlässigen und genauen Deformationsanalyse. Diese Ergebnisse sind unmittelbar relevant für alle flächenhaften Approximationen mit hohen Genauigkeitsanforderungen. Im Gesamten stellt diese Dissertation also eine Grundlage zur verbesserten Analyse, Bewertung und Interpretation von Approximationen auf Basis ungleichmäßig abgetasteter Oberflächen dar. Eingebettet in ebenfalls erwähnte, weiterführende methodische Untersuchungen ist diese Dissertation damit bei der für die Ingenieurgeodäsie angestrebten ganzheitlichen Raumkontinuisierung von großem NutzenAnalysis of the configuration at approximating irregularly sampled surfaces based on levellings and terrestrial laser scans Since several years, the field of engineering geodesy has been subject to change. This is due to the fact that engineering geodesy generally attends to applied problem statements. Based on these aspects, especially the area-based acquisition of objects and their geometries – up to an integrated space continualization – got into focus of engineering geodesy. In this context, this dissertation fathoms the possibility of analyzing and optimizing the configuration at approximation surfaces that are spatially irregularly sampled. The underlying measurements are based on levellings and terrestrial laser scans, which both sample the surface irregularly. With levellings, the reason for the irregular sampling is caused by cost effectiveness and the settlement structure of the investigated areas. With terrestrial laser scanning (TLS), the reason is caused by its polar sampling due to its measurement technology. In both cases, the sampling points are often used for approximating surfaces in order to gain area-based conclusions. Established applications are, e.g., the analysis of ground subsidence with levellings or the area-based deformation analysis with TLS. The configuration of approximation suffers from the irregular spatial distribution of the sampling points even if these sampling points are of sufficient quantity. In combination with limited model knowledge, this can result in biased parameter estimates when modelling surfaces. Hence, the configuration needs to be analyzed and – if necessary – also optimized. Based on these methodical analyses, four aspects can be highlighted with emphasis: 1) It can be exposed that the irregular distribution of sampling points in combination with limited model knowledge results in a suboptimal configuration at approximating surfaces. This analysis rests on partial redundancies and relative differences in partial redundancies. Partial redundancies combine the geometric distribution of the sampling points, the object geometry and the stochastic model of the observations for evaluating the reliability and configuration. 2) For optimizing this configuration at approximating area-based levellings, an algorithm is developed. This algorithm objectively evaluates the spatial distribution of the sampling points dependent on the complexity of the ground subsidence. Existing sampling points are selected based on their importance for the approximation – judged by the configuration analysis. Furthermore, the number and position of additionally required sampling points can be determined for the first time in geodetic network optimization. 3) The parameter estimates of scanned surfaces are often biased and due to the station of the laser scanner. This can be quantified and analyzed based on a configuration analysis considering the partial redundancies. A data reduction – which equals a thinning of the point cloud to gain a regular sampling – minimizes the dependence of the parameter estimates on the laser scanner station. This can also be seen in the improved configuration. 4) An advanced concept for laser scanner based deformation analyses integrates the described aspects of configuration analysis and optimization for a concrete application. In this context, also the aspect of laser scanner calibration is pointed out and integrated into this deformation analysis. These steps altogether imply an immense progress at using terrestrial laser scanners for reliable and accurate deformation analyses. These results are instantaneously relevant for all surface-based approximations demanding high accuracy. Overall, this thesis builds up a fundament for an improved analysis, evaluation and interpretation of area-based approximations based on irregularly sampled surfaces. Embedded in other mentioned methodical aspects, this thesis is of great benefit for the integrated space continualization aspired in engineering geodesy

Foregut separation and tracheo-oesophageal malformations: The role of tracheal outgrowth, dorso-ventral patterning and programmed cell death

Foregut division—the separation of dorsal (oesophageal) from ventral (tracheal) foregut components—is a crucial event in gastro-respiratory development, and frequently disturbed in clinical birth defects. Here, we examined three outstanding questions of foregut morphogenesis. The origin of the trachea is suggested to result either from respiratory outgrowth or progressive septation of the foregut tube. We found normal foregut lengthening despite failure of tracheo-oesophageal separation in Adriamycin-treated embryos, whereas active septation was observed only in normal foregut morphogenesis, indicating a primary role for septation. Dorso-ventral patterning of Nkx2.1 (ventral) and Sox2 (dorsal) expression is proposed to be critical for tracheo-oesophageal separation. However, normal dorso-ventral patterning of Nkx2.1 and Sox2 expression occurred in Adriamycin-treated embryos with defective foregut separation. In contrast, Shh expression shifts dynamically, ventral-to-dorsal, solely during normal morphogenesis, particularly implicating Shh in foregut morphogenesis. Dying cells localise to the fusing foregut epithelial ridges, with disturbance of this apoptotic pattern in Adriamycin, Shh and Nkx2.1 models. Strikingly, however, genetic suppression of apoptosis in the Apaf1 mutant did not prevent foregut separation, indicating that apoptosis is not required for tracheo-oesophageal morphogenesis. Epithelial remodelling during septation may cause loss of cell-cell or cell-matrix interactions, resulting in apoptosis (anoikis) as a secondary consequence

A Q-model of labour demand

This paper studies the labour demand using a Q model in which labour and capital entail adjustment costs. The estimates are based on an unbalanced panel of Spanish firms over the period 1989-96. The corresponding Q variable for labour is significant in explaining hiring rates. Its estimated coefficient varies across sectors in a way that suggests that the use of temporary labour is more widespread in those economic sectors that incur smaller costs of adjusting labour factor due to the specific characteristics of their technology and economic activity. Interaction effects between investment and labour demands are also observed in their adjustment costs