A Decomposition Approach for a New Test-Scenario in Complex Problem Solving

Over the last years, psychological research has increasingly used computer-supported tests, especially in the analysis of complex human decision making and problem solving. The approach is to use computer-based test scenarios and to evaluate the performance of participants and correlate it to certain attributes, such as the participant's capacity to regulate emotions. However, two important questions can only be answered with the help of modern optimization methodology. The first one considers an analysis of the exact situations and decisions that led to a bad or good overall performance of test persons. The second important question concerns performance, as the choices made by humans can only be compared to one another, but not to the optimal solution, as it is unknown in general.\ud \ud Additionally, these test-scenarios have usually been defined on a trial-and-error basis, until certain characteristics became apparent. The more complex models become, the more likely it is that unforeseen and unwanted characteristics emerge in studies. To overcome this important problem, we propose to use mathematical optimization methodology not only as an analysis and training tool, but also in the design stage of the complex problem scenario.\ud \ud We present a novel test scenario, the IWR Tailorshop, with functional relations and model parameters that have been formulated based on optimization results. We also present a tailored decomposition approach to solve the resulting mixed-integer nonlinear programs with nonconvex relaxations and show some promising results of this approach

Can non-linear real shocks explain the persistence of PPP exchange rate disequilibria?

A core stylized fact of the empirical exchange rate literature is that half-life deviations of equilibrium real exchange rates from levels implied by Purchasing Power Parity (PPP) are very persistent. Empirical efforts to explain this persistence typically proceed along two distinct paths, resorting either to the presence of real shocks such as productivity differentials that drive equilibrium exchange rates away from levels implied by PPP, or the presence of non-linearities in the adjustment process around PPP. By contrast, we combine these two explanations in the context of an innovative panel estimation methodology. We conclude that both explanations are relevant to the behavior of exchange rates and that resulting half-lives are much shorter than estimated using linear PPP and more consistent with the observed volatility of nominal and real exchange rates. JEL Classification: F31, C23, L6-L9Balassa-Samuelson, EPSTAR, exchange rate, PPP, productivity

Exchange rate modelling and forecasting

The objective of this thesis is to assess the current state of exchange rate modelling and forecasting. The thesis has four distinct essays, each one analysing a current interest topic in this wide and vibrant area of economic research. But a common thread runs through all four: to determine whether it is possible to use the results of this research to develop trading strategies that can add persistent value to international investment portfolios with significant exposure to the foreign exchange market. This market has a daily turnover of $1.9 trillion (BIS, 2004) and is the most liquid financial exchange in the world, by some distance. Nonetheless, we argue that the market is also inefficient, in the sense that profitable trading opportunities persist and that prices do not reflect all available public information on a continuous basis. If we are correct-and we present simulation results that suggest we are-then the opportunity to derive and test plausible trading rules for the management of international investment portfolios though rigorous academic research is enormous. Yet all too often academic exchange rate research appears to be conducted in a cocoon, with the result that conclusions are sometimes difficult to apply in a practical context by portfolio managers. These difficulties reflect the computational requirements of implementing highly intensive trading strategies, associated trading costs and size limitations, and the practical limitations on implementation raised by publication lags and general data limitations. We aim to address these difficulties throughout this thesis. By assessing the merits of various theoretical models that collectively encompass all of the main themes on the current research agenda, we will be in a position to appreciate both the statistical and economic value of existing academic research, isolating areas of real merit for the investment community, and suggesting areas for further attention

Surgical Approaches in Shoulder Arthroplasty

Shoulder arthroplasty is a complex procedure that is becoming increasingly more utilized throughout the world. Due to the numerous static and dynamic stabilizers of the glenohumeral joint, along with the relative proximity to vital neurovascular structures, great care must be taken to access the joint in a safe and effective manner. To date, there are two well-described approaches utilized in shoulder arthroplasty: the deltopectoral approach and the anterosuperior approach. Both of these approaches are effective in accessing the glenohumeral joint; however, due to their anatomic location, they both have distinct advantages and disadvantages. The aim of this book chapter is to describe the methodology for approaching the glenohumeral joint through each of these approaches, as well as to discuss the advantages and disadvantages of utilizing each. In addition, we aim to discuss the various methodologies for closing these wounds and, briefly, to discuss the other approaches described in the orthopedic literature

Optimization as an analysis tool for human complex decision making

We present a problem class of mixed-integer nonlinear programs (MINLPs) with nonconvex continuous relaxations which stem from economic test scenarios that are used in the analysis of human complex problem solving. In a round-based scenario participants hold an executive function. A posteriori a performance indicator is calculated and correlated to personal measures such as intelligence, working memory, or emotion regulation. Altogether, we investigate 2088 optimization problems that differ in size and initial conditions, based on real-world experimental data from 12 rounds of 174 participants. The goals are twofold. First, from the optimal solutions we gain additional insight into a complex system, which facilitates the analysis of a participant’s performance in the test. Second, we propose a methodology to automatize this process by providing a new criterion based on the solution of a series of optimization problems. By providing a mathematical optimization model and this methodology, we disprove the assumption that the “fruit fly of complex problem solving,” the Tailorshop scenario that has been used for dozens of published studies, is not mathematically accessible—although it turns out to be extremely challenging even for advanced state-of-the-art global optimization algorithms and we were not able to solve all instances to global optimality in reasonable time in this study. The publicly available computational tool Tobago [TOBAGO web site https://sourceforge.net/projects/tobago] can be used to automatically generate problem instances of various complexity, contains interfaces to AMPL and GAMS, and is hence ideally suited as a testbed for different kinds of algorithms and solvers. Computational practice is reported with respect to the influence of integer variables, problem dimension, and local versus global optimization with different optimization codes

Exchange rate modelling and forecasting

The objective of this thesis is to assess the current state of exchange rate modelling and forecasting. The thesis has four distinct essays, each one analysing a current interest topic in this wide and vibrant area of economic research. But a common thread runs through all four: to determine whether it is possible to use the results of this research to develop trading strategies that can add persistent value to international investment portfolios with significant exposure to the foreign exchange market. This market has a daily turnover of $1.9 trillion (BIS, 2004) and is the most liquid financial exchange in the world, by some distance. Nonetheless, we argue that the market is also inefficient, in the sense that profitable trading opportunities persist and that prices do not reflect all available public information on a continuous basis. If we are correct-and we present simulation results that suggest we are-then the opportunity to derive and test plausible trading rules for the management of international investment portfolios though rigorous academic research is enormous. Yet all too often academic exchange rate research appears to be conducted in a cocoon, with the result that conclusions are sometimes difficult to apply in a practical context by portfolio managers. These difficulties reflect the computational requirements of implementing highly intensive trading strategies, associated trading costs and size limitations, and the practical limitations on implementation raised by publication lags and general data limitations. We aim to address these difficulties throughout this thesis. By assessing the merits of various theoretical models that collectively encompass all of the main themes on the current research agenda, we will be in a position to appreciate both the statistical and economic value of existing academic research, isolating areas of real merit for the investment community, and suggesting areas for further attention.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Mutation of the co-chaperone Tsc1 in bladder cancer diminishes Hsp90 acetylation and reduces drug sensitivity and selectivity

The molecular chaperone Heat shock protein 90 (Hsp90) is essential for the folding, stability, and activity of several drivers of oncogenesis. Hsp90 inhibitors are currently under clinical evaluation for cancer treatment, however their efficacy is limited by lack of biomarkers to optimize patient selection. We have recently identified the tumor suppressor tuberous sclerosis complex 1 (Tsc1) as a new co-chaperone of Hsp90 that affects Hsp90 binding to its inhibitors. Highly variable mutations of TSC1 have been previously identified in bladder cancer and correlate with sensitivity to the Hsp90 inhibitors. Here we showed loss of TSC1 leads to hypoacetylation of Hsp90-K407/K419 and subsequent decreased binding to the Hsp90 inhibitor ganetespib. Pharmacologic inhibition of histone deacetylases (HDACs) restores acetylation of Hsp90 and sensitizes Tsc1-mutant bladder cancer cells to ganetespib, resulting in apoptosis. Our findings suggest that TSC1 status may predict response to Hsp90 inhibitors in patients with bladder cancer, and co-targeting HDACs can sensitize tumors with Tsc1 mutations to Hsp90 inhibitors

Precolostral serology in calves born from Neospora -seropositive mothers

The present study was designed to exploratively determine (a) how many healthy calves, born from seropositive mothers, were also precolostrally seropositive; (b) how many precolostrally negative calves became postcolostrally positive; and (c) in these calves, how the IgG1/IgG2 situation developed pre- and postcolostrally. All calves were born from mothers that were determined to be seropositive in a conventional Neospora caninum-ELISA and by immunoblotting. When the diagnostic performance of the conventional ELISA was compared with that of immunoblotting and an IgG1/IgG2-ELISA in the calves, the latter two exhibited a higher sensitivity: From a total of 15 precolostral calf sera, 7 were positive in the conventional ELISA (diagnostic sensitivity 47%) compared to 15 that were positive by immunoblotting (diagnostic sensitivity 100%) and 12 that were positive by the IgG1/IgG2-ELISA (diagnostic sensitivity 80%). With regard to IgG1/IgG2 findings in the dams, IgG2 appeared as the dominant subclass in the humoral immune response of adult cattle, while in calves, IgG1 appeared as the main prenatally/precolostrally reactive antibody isotype. Provided that precolostral seropositivity reflects postnatal persistent infection with N. caninum, we then postulate that, basically, all of our study calves born form N. caninum-seropositive mothers were prenatally infected with the parasite, and may, thus, all become members of the next transmitting generatio

Inflationsvolatilitetens samband med sparkvot och humankapital - en studie av upphinnarländer med hög volatil inflation

Syftet med studien var att utföra en empirisk undersökning för att ta reda på ifall de teoretiska resonemangen kring inflationsvolatilitetens inverkan på sparkvot och humankapital har stämt överens med verkligheten. Genom att empiriskt undersöka 14 upphinnarländer under 30 år har, sambandet mellan hög volatilitet i inflationsnivåer, sparkvot och humankapital observerats. Urvalet av länder har baserats på tillväxttakt och inflationsvolatilitet, tillgänglig data och kriteriet att landet befunnit sig under sin steady-state nivå i en majoritet av tidsperioden. Enligt det empiriska resultatet går det inte att statistiskt säkerställa att inflationsvolatilitet har någon inverkan på humankapital. Det är därför inte möjligt att dra några slutsatser kring vad den potentiella osäkerheten på arbetsmarknaden har för inverkan på preferenser kring antal utbildningsår. Inflationsvolatilitet har, enligt studiens empiriska undersökning, ett negativt samband med investeringar. För varje enhet inflationsvolatiliteten ökar, minskar sparkvoten med 0,0214 procentenheter. Eftersom sparkvot är en drivande faktor i ekonomisk tillväxt är det motiverat att regeringar och centralbanker lägger energi på att upprätthålla en stabil inflation

Developing and Field Testing Design Parameters for Customizing Agricultural Extension Education Systems in Developing Countries.

Increasingly, developing countries view the partnership of research, education, and extension in traditional agricultural extension education systems as an adaptable model for improving their agrarian economies. The process of adaptation, however, has too often followed the traditional developmental project approach and been little more than the transplantation of a predefined extension education model into a developing country with little regard to existing country specific factors which impact the effectiveness of a domestic extension system. As a result, less than satisfactory technology transfer has occurred and slow rates of agricultural economic development have been posted, painting a disappointing record for agricultural extension in developing countries. The general assertion remains, however, that extension education can promote development by improving the capacity of small farmers to produce food and fiber, enabling them to become functional, contributing parts of the economic development process. The challenge is to design an extension system, within country specific parameters, which will effectively meet the established developmental goals of a country. The purpose of this developmental research project was to identify the factors to consider when designing an effective agricultural extension system for a given developing country and then link these factors to the components of existing extension models to custom design an appropriate, effective extension system for the country. A review of literature identified country specific factors which impact the effectiveness of an extension system and the primary components of the seven major extension models. Additional procedures included the development of two instruments, the Country Analysis Instrument which serves to identify and quantify various existing or desired characteristics which impact the development of an extension system and the Model Correlation Instrument which correlates these identified impactors to particular components of existing models. The designed instruments were subjected to a modified Delphi review by a panel of recognized experts in extension education and development for evaluation and refinement. Field-testing of the final instruments was done in the Peoples\u27 Republic of China and Cambodia through a 1994 Fulbright Project and Turkmenistan in a 1995 USAID Project. These studies validated the instruments as capable of withstanding practical application