1,842 research outputs found
Ask questions, get sales : close the deak and create long-term relationships / Stephan Schiffman.
No full textIncludes index.v, 168 pages ;In Ask Questions, Get Sales, the author and sales guru Stephan Schiffman helps readers boost their careers to the gold-medal level by teaching them how to strengthen their questioning skills during the sales process. The premise is simple yet effective: In order to be successful, salespeople need to change their mindset from "need-orientated" to "do-orientated". The message of the book centers around six core "do" questions: What do you do? How do you do it? When and where do you do it? Why do you do it that way? Who do you do it with? How can we help you do it better? With this indispensable guide in their briefcase, salespeople will have information at the ready to score big sales over the short term and the long term
Unemployment Benefits and Unemployment Rates of Low-Skilled and Elder Workers in West Germany: A Search Equilibrium Approach
No full textApproach Author & abstract Download 16 References 1 Citations Related works & more Corrections Author Listed: Launov, Andrey ([email protected]) (University of Kent) Wolff, Joachim ([email protected]) (Institute for Employment Research (IAB), Nuremberg) Klasen, Stephan ([email protected]) (University of Göttingen) Registered: Stephan Klasen Abstract In this paper we investigate whether the extension of the entitlement to unemployment benefits in the mid 80s can explain the increase in the unemployment rates of unskilled and elder workers in western Germany. To answer this question we estimate a version of the Burdett-Mortensen search equilibrium model and analyze how workers’ search behaviour responded to these reforms. We try both nonparametric and fully-parametric estimation methods and identify the cases in which the nonparametric approach cannot be applied. We find that the entitlement reforms are largely responsible for the increase of unemployment among unskilled workers
Unemployment Benefits and Unemployment Rates of Low-Skilled and Elder Workers in West Germany: A Search Equilibrium Approach
No full textApproach Author & abstract Download 16 References 1 Citations Related works & more Corrections Author Listed: Launov, Andrey ([email protected]) (University of Kent) Wolff, Joachim ([email protected]) (Institute for Employment Research (IAB), Nuremberg) Klasen, Stephan ([email protected]) (University of Göttingen) Registered: Stephan Klasen Abstract In this paper we investigate whether the extension of the entitlement to unemployment benefits in the mid 80s can explain the increase in the unemployment rates of unskilled and elder workers in western Germany. To answer this question we estimate a version of the Burdett-Mortensen search equilibrium model and analyze how workers’ search behaviour responded to these reforms. We try both nonparametric and fully-parametric estimation methods and identify the cases in which the nonparametric approach cannot be applied. We find that the entitlement reforms are largely responsible for the increase of unemployment among unskilled workers
Measuring Vulnerability to Poverty Using Long-Term Panel Data
No full textMeasuring Vulnerability to Poverty Using Long-Term Panel Data Author & abstract Download & other version 16 References 4 Citations Related works & more Corrections Author Listed: Katja Landau (Georg-August-University Göttingen) Stephan Klasen (Georg-August-University Göttingen) Walter Zucchini (Georg-August-University Göttingen) Registered: Stephan Klasen Abstract We investigate the accuracy of ex ante assessments of vulnerability to income poverty using cross-sectional data and panel data. We use long-term panel data from Germany and apply di fferent regression models, based on household covariates and previous-year equivalence income, to classify a household as vulnerable or not. Predictive performance is assessed using the Receiver Operating Characteristics (ROC), which takes account of false positive as well as true positive rates. Estimates based on cross-sectional data are much less accurate than those based on panel data, but for Germany, the accuracy of vulnerability predictions is limited even when panel data are used. In part this low accuracy is due to low poverty incidence and high mobility in and out of poverty
Measuring Vulnerability to Poverty Using Long-Term Panel Data
No full textMeasuring Vulnerability to Poverty Using Long-Term Panel Data Author & abstract Download & other version 16 References 4 Citations Related works & more Corrections Author Listed: Katja Landau (Georg-August-University Göttingen) Stephan Klasen (Georg-August-University Göttingen) Walter Zucchini (Georg-August-University Göttingen) Registered: Stephan Klasen Abstract We investigate the accuracy of ex ante assessments of vulnerability to income poverty using cross-sectional data and panel data. We use long-term panel data from Germany and apply di fferent regression models, based on household covariates and previous-year equivalence income, to classify a household as vulnerable or not. Predictive performance is assessed using the Receiver Operating Characteristics (ROC), which takes account of false positive as well as true positive rates. Estimates based on cross-sectional data are much less accurate than those based on panel data, but for Germany, the accuracy of vulnerability predictions is limited even when panel data are used. In part this low accuracy is due to low poverty incidence and high mobility in and out of poverty
Evaluation of in-store processes related to returnable packaging services offered in grocery stores - the store management perspective
No full textAuthor Stephan LehnerMasterarbeit Universität Linz 202
Evaluation of in-store processes related to returnable packaging services offered in grocery stores - the store management perspective
No full textAuthor Stephan LehnerMasterarbeit Universität Linz 202
Second-order approximations to pricing and hedging in presence of jumps and stochastic volatility
No full textThis thesis deals with two basic problems of Mathematical Finance, namely the pricing and hedging of European-style derivatives. We analyze these questions in models that describe the asset underlying the derivative by a process with jumps and stochastic volatility. However, we are not interested in exact solutions to the mentioned problems but in reasonable approximations that allow for a better insight into the structure of the respective question.
More precisely, we consider hedging problems in geometric Lévy models, i.e., in models where the logarithmic price process of the underlying follows a process with independent and stationary increments. In this kind of models, there typically exist no perfect hedging strategies. We quantify the remaining risk of a self-financing trading strategy by its mean squared hedging error, i.e., the second moment of the difference between the payoff of the derivative and the terminal wealth of the hedging portfolio.
We study the question of derivative pricing in a comprehensive model class that encompasses geometric Lévy models and several stochastic volatility models from the literature. In doing so, we consider prices that are compatible with the absence of arbitrage, i.e., prices that do not allow for riskless gains.
For several hedging strategies, for their hedging errors, as well as for derivative prices in the described framework, the literature provides semi-explicit representations that can be efficiently evaluated numerically for many parametric models. However, these representations admit little understanding, e.g., of the determining factors of the respective quantity. We develop approximate solutions that provide more insight in this respect. To this end, we interpret the complex model with jumps and stochastic volatility as a perturbed Black-Scholes model, and we compute correction terms of second order. Our approach differs from traditional perturbation techniques in the sense that in our case, there is no univariate problem-inherent parameter that quantifies the amount of perturbation. Therefore, we develop a general framework for perturbation approaches in this situation, and we apply this approach in the models under consideration.
The approximate solutions obtained in this way consist of few moments of components of the asset price process as well as of sensitivities (greeks) of the Black-Scholes derivative price. In particular, the formulas do not depend on the fine structure of the considered model and are robust in this sense. We show in detailed numerical experiments that our approximations yield satisfactory results in several parametric models from the literature.In dieser Arbeit betrachten wir zwei grundlegende Probleme der Finanzmathematik, nämlich die Bewertung und die Absicherung (Hedging) von Derivaten mit europäischer Auszahlungsstruktur. Wir führen unsere Analyse in Modellen durch, die das dem Derivat zugrunde liegende Wertpapier durch einen Prozess mit Sprüngen und stochastischer Volatilität abbilden. Dabei interessieren wir uns nicht für exakte Lösungen der genannten Probleme, sondern für sinnvolle Näherungslösungen mit dem Hauptziel, einen besseren Einblick in die Struktur der jeweiligen Frage zu erhalten.
Genauer betrachten wir Hedgingprobleme in geometrischen Lévy-Modellen, das heißt in Modellen, in denen der logarithmische Wertpapierkurs einem Prozess mit unabhängigen und stationären Zuwächsen folgt. In solchen Modellen existieren typischerweise keine perfekten Absicherungsstrategien. Das Restrisiko einer selbstfinanzierenden Hedgingstrategie bewerten wir durch den mean squared hedging error, das heißt durch das zweite Moment der Differenz von Derivatauszahlung und Endwert der Absicherungsstrategie.
Die Frage der Derivatbewertung studieren wir in einer großen Modellklasse, die geometrische Lévy-Modelle, aber auch diverse stochastische Volatilitätsmodelle aus der Literatur umfasst. Dabei betrachten wir mit Arbitragefreiheit verträgliche Preise, das heißt solche, die risikolose Gewinne nicht zulassen.
Für verschiedene Hedgingstrategien, für deren Hedgefehler sowie für Derivatpreise existieren für den von uns betrachteten Rahmen semi-explizite Darstellungen in der Literatur, die sich für viele parametrische Modelle numerisch effizient auswerten lassen. Allerdings erlauben diese Darstellungen wenig Einsicht zum Beispiel in die für die jeweilige Größe entscheidenden Einflussfaktoren. Wir entwickeln in dieser Hinsicht besser interpretierbare Näherungslösungen, die wir durch Perturbationstechniken gewinnen. Dazu fassen wir das komplexe Modell mit Sprüngen und stochastischer Volatilität als Störung eines einfachen Black-Scholes-Modells auf und berechnen Korrekturterme zweiter Ordnung. Ein wesentlicher Unterschied zu klassischen Perturbationsansätzen besteht darin, dass in unserem Fall kein dem Problem immanenter univariater Parameter existiert, der die Störung quantifiziert. Wir entwickeln deshalb zunächst einen allgemeinen Rahmen für Perturbationstechniken in dieser Situation und wenden diesen dann in
den
betrachteten Modellen an.
Die so gewonnenen Näherungslösungen setzen sich aus wenigen Momenten von Komponenten des Wertpapierprozesses sowie aus Sensitivitäten (greeks) des Black-Scholes-Preises des betrachteten Derivats zusammen. Die Näherungen hängen insbesondere nicht von der Feinstruktur des betrachteten Modells ab und sind in diesem Sinne robust. In ausführlichen numerischen Experimenten zeigen wir, dass unsere Approximationen in verschiedenen parametrischen Modellen aus der Literatur zufriedenstellende Ergebnisse liefern
On the Black-Scholes Strategy in Exponential Lévy Models
No full textVarianz-optimales Hedging ist eine klassische Methode zur Bestimmung von geeigneten Absicherungsstrategien in unvollständigen Märkten. Als Maß für die Güte eines Portfolios dient bei diesem Ansatz der erwartete quadratische Hedgefehler. In der vorliegenden Diplomarbeit wird untersucht, inwiefern sich die Black-Scholes-Strategie zur Absicherung von europäischen Optionen im Sinne dieses Risikokriteriums eignet, wenn der Preisprozess des Underlyings einem exponentiellen Lévy-Modell folgt. Dazu wird für den erwarteten quadratischen Hedgefehler der Black-Scholes-Strategie eine semi-explizite Formel hergeleitet, welche durch die kumulantenerzeugende Funktion des treibenden Lévy- Prozesses und eine Integraldarstellung des Payoffs ausgedrückt wird. Ein numerisches Beispiel zeigt, dass diese Formel einfach und schnell ausgewertet werden kann. Ferner erweist sich der Black-Scholes-Hedge als gute Approximation der varianz-optimalen Strategie, insbesondere für moderate Driftraten des Underlyings und kurze Optionslaufzeiten
Hybrid simulation of wake vortices of landing aircraft in a turbulent environment
No full textWake-vortex evolution during landing of a long range aircraft is investigated in a turbulent environment. The simulations cover final approach, touchdown on the tarmac, and the evolution of the wake after touchdown. An ambient turbulent crosswind and headwind field is generated in a pre-simulation. The wake is initialized using a RANS-LES coupling approach. The further development of the vortical wake is investigated by large-eddy simulation until final decay. Strong three-dimensional deformations appearing after touchdown and linkings with the ground are studied. The downwind vortex is strongly advected with crosswind and decays quickly. The interaction of plate line disturbances and end effects in a turbulent environment leads to irregular decay pattern
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