23 research outputs found
Using penalized spline, generalized additive model and mixed model regression techniques to examine univariate and multivariate time series and in particular business cycles
Get PDFTeuber T. Using penalized spline, generalized additive model and mixed model regression techniques to examine univariate and multivariate time series and in particular business cycles. Bielefeld: Universität Bielefeld; 2013
Wage Bargaining and Induced Technical Change in a Linear Economy: Model and Application to the US (1963-2003)
Get PDFIn a simple one-sector, two-class, fixed-proportions economy, wages are set through axiomatic bargaining a`la Nash (1950). As for choice of technology, firms choose the direction of factor augmentations to maximize the rate of unit cost reduction (Kennedy 1964, and more recently Funk 2002). The ag-gregate environment resulting by self-interested decisions made by economic agents is described by a two-dimensional dynamical system in the employment rate and output/capital ratio. The economy converges cyclically to a long-run equilibrium involving a Harrod-neutral profile of technical change, a constant rate of employment of labor, and constant input shares. The type of oscillations predicted by the model matches the available data on the United States (1963-2003). Finally, institutional change, as captured by variations in workers’ bargaining power, has a positive effect on the rate of output growth but a negative effect on employment.Bargaining, Induced Technical Change, Factor Shares, Employment.
Wage Bargaining and Induced Technical Change in a Linear Economy: Model and Application to the US (1963-2003)
Get PDFIn a simple one-sector, two-class, fixed-proportions economy, wages are set through axiomatic bargaining a la Nash [1950]. As for choice of technology, firms choose the direction of factor augmentations to maximize the rate of unit cost reduction (Kennedy [1964], and more recently Funk [2002]). The aggregate environment resulting by self-interested decisions made by economic agents is described by a two-dimensional dynamical system in the employment rate and output/capital ratio. The economy converges cyclically to a long-run equilibrium involving a Harrod-neutral prole of technical change, a constant rate of employment of labor, and constant input shares. The type of oscillations predicted by the model matches the available data on the United States (1963-2003). Finally, institutional change, as captured by variations in workers' bargaining power, has a positive effect on the rate of output growth but a negative effect on employment.Bargaining; Induced Technical Change; Factor Shares; Employment
Exploring US Business Cycles with Bivariate Loops Using Penalized Spline Regression
No full textKauermann G, Teuber T, Flaschel P. Exploring US Business Cycles with Bivariate Loops Using Penalized Spline Regression. Computational Economics. 2012;39(4):409-427.The phrase business cycle is usually used for short term fluctuations in macroeconomic time series. In this paper we focus on the estimation of business cycles in a bivariate manner by fitting two series simultaneously. The underlying model is thereby nonparametric in that no functional form is prespecified but smoothness of the functions are assumed. The functions are then estimated using penalized spline estimation. The bivariate approach will allow to compare business cycles, check and compare phase lengths and visualize this in forms of loops in a bivariate way. Moreover, the focus is on separation of long and short phase fluctuation, where only the latter is the classical business cycle while the first is better known as Friedman or Goodwin cycle, respectively. Again, we use nonparametric models and fit the functional shape with penalized splines. For the separation of long and short phase components we employ an Akaike criterion
Advanced quantum cascade laser infrared attenuated total reflection spectroscopy
No full textThe overarching topic of this cumulative thesis is the development and application of next-generation quantum cascade laser (QCL) based infrared attenuated total reflection (IR-ATR) infrared spectroscopy.
Cascade lasers (i.e., interband and quantum cascade lasers; ICLs, QCLs) are considered the most advanced mid-infrared light sources, as discussed and exemplified in the introduction section of this dissertation. The characteristic properties of quantum cascade lasers include a broad spectral coverage and tunability in the mid-infrared range (MIR; 3 – 12 µm), well-defined spectral properties, and a high energy density within the emitted spectral band. As a result, spectroscopic information can be obtained based on differentiating molecular signatures. Consequently, the remainder of this cumulative thesis focuses on a variety of analytical applications capitalizing on the unique properties of cascade lasers presented as a series of peer-reviewed research articles.
If laser light sources are combined with appropriate transducers, numerous application opportunities arise in a variety of scenarios ranging from environmental monitoring to bioanalytics. Hence, the development of innovative sensor technologies is an important yet challenging topic. The main purpose of the transducer in optical sensors is to ensure reproducible interaction between the sample and the photons, i.e., herein, light emitted by the laser light source. This is of particular interest if optical sensing technologies aim at taking advantage of inherent molecular specificity without additional chem/bio recognition architectures, as is the case for mid-infrared spectroscopic concepts. While the aforementioned scenarios – environmental vs. life science applications – clearly have their specific needs and requirements, both may capitalize on similar fundamental photonic concepts and building blocks, which are at the core of the present thesis, i.e., mid-infrared laser and mid-infrared waveguide technology.
Analyzing molecular constituents in real-world environmental scenarios requires measurement techniques that may particularly withstand harsh external conditions while providing robust and reliable analytical data. Only a few infrared spectroscopic systems have been developed for harsh environments with most devices in routine practice being deployed in appropriate research facilities providing for a constant measurement environment without the need for portable or mobile devices. Among the most robust sensing concepts in mid-infrared photonics are transducers/sampling interfaces based on single or multiple reflection waveguides facilitating IR-ATR (i.e., evanescent field absorption) spectroscopy, which are readily adaptable to harsh conditions as shown in the present thesis. To this end, conventional multi-reflection ATR concepts were augmented with substrate-integrated hollow waveguide (iHWG) technology pioneered by our research team yielding an exceedingly robust modular transducer platform. This was achieved by developing an iHWG-based invariant light coupling concept for coupling IR photons to an ATR waveguide without the need for any additional optics in a robust and compact arrangement. This innovative assembly was proven useful for conventional broadband IR spectroscopy using Fourier transform infrared spectrometers, as well as QCLs. In the course of this thesis, a robust MIR sensor system was developed for mobile measurement applications at harsh environmental or process analytical conditions. The versatility of the developed sensor technology was demonstrated by coupling to a variety of light sources, the optional use of MIR fiberoptics, and by investigating a series of relevant analytes.
Bioanalytical sensing technologies frequently require addressing exceedingly small sample volumes/quantities or directly addressing live biological specimens or systems. This requires biocompatible and chemically inert transducers when probing samples in life science applications. To this end, diamond is an ideal waveguide material that next to its inertness and biocompatibility provides a broad spectral transmission window that extends well into the MIR regime, which is of particular interest for the present thesis. While conventional diamond ATR crystals with only a few internal reflections readily exist, the present thesis was focused on optimizing frequency-matched thin-film diamond waveguide technology ideally combining with QCL light sources. Using nanocrystalline diamond layers with a thickness of around 20 µm, near single-mode waveguiding behavior has been achieved yielding a homogeneous evanescent field at the waveguide surface rather than hotspots, as encountered via discrete internal reflections using macroscopic ATR waveguides. Thereby, highly miniaturized sensing concepts are facilitated without trading off size against sensitivity. The performance and quantitative analytical capabilities of QCL-based MIR sensors combined with thin-film diamond waveguides were compared to conventional IR-ATR technology for the exemplary analyte caffeine, which is among the most commonly ingested psychoactive substances found in simulating beverages such as tea, coffee, or energy drinks.
The utility of the developed sensing concepts was also shown for the analysis of live biological specimens, i.e., model bacteria, whereby biofilm formation processes were studied in molecular detail using QCLs combined with diamond thin-film waveguide technology for the first time. Different growth phases of bacteria were analyzed and compared with conventional IR spectroscopic data confirming the feasibility of IR laser spectroscopy for complex bioanalytical application scenarios.
Finally, even though QCLs combined with diamond thin-film waveguide technology gave rise to adequately sensitive measurement concepts, there are analytical scenarios where even more sensitivity is required. Hence, it was shown that the strategy of surface-enhanced infrared absorption (SEIRA) spectroscopy may be readily adapted for harnessing the MIR sensing technologies developed in this thesis, especially by using graphene for amplifying selected infrared signatures.
In summary, the results of this cumulative thesis were published within ten peer-reviewed contributions in leading international journals, including seven of them as a first author. A review contribution introduces the fundamentals of cascade lasers and their applications providing selected highlight examples published as a book chapter. The obtained research results address two main areas – environmental/process analytical scenarios and bioanalytics – demonstrating the versatility of waveguide-based laser spectroscopy in the mid-infrared contributing three publications each to robust IR-ATR concepts suitable for harsh environments, and to advanced thin-film diamond waveguide technology for bioanalytical scenarios
Interpreting Business Cycles as Generalized Two-Dimensional Loops Using Penalized Splines Regression Techniques
No full textSalvation: Into the Cosmos: Board Game Project Blending 4X and Eurogame Styles
Get PDFThis project is an attempt at creating a shorter and simpler 4X strategy game. To do this, the author takes elements of the Eurogame genre and combines aspects of The Settlers of Catan by Klaus Teuber and Shattered Plans by Jagex while following the requirements of the German board game award, the Spiel de Jahres. After following the traditional game design process of conceptualization, prototyping, and repeated testing, analysis, and revision, the author succeeded in creating a core foundation for such a game that also had marketing potential on its own
Action and Drama: American Film Titles in Japanese
Get PDFJapanese titles of foreign films come in many varieties, from direct translation to phonetic representation to something completely different from the original title. This study looks at trends among the Japanese titles of over 6000 American action films and drama films over the past 100 years. The author created a spreadsheet of titles from an online film database and examined katakana usage in each genre decade by decade from the 1920s to present day. The author found that these genres differ greatly from each other in the percentage of katakana-only titles, and in how likely those titles are to be phonetic representations of the original English titles. Finally, the author discovered katakana and Japanese words that occur disproportionately in Japanese titles when compared to their English equivalent in the original titles
An Analysis of the Nonce-Words of Dr. Seuss
Get PDFThe books of children’s author Dr. Seuss are filled with nonce-words—novel word formations that can only be understood within the context of the books. This paper is an attempt to analyze a subset of these nonce-words and their phonological and orthographical structure. A database of 377 words from 33 books was created and the words were analyzed in terms of their internal structure as well as in their context in the books. The author found that a significant amount of these neologisms were likely influenced by the poetic constructs of rhyme and alliteration. In addition, certain characteristics of the nonce-words were examined, and possible reasons are given to explain their use. These characteristics include unusual word-final double consonants, and the extensive use of the letter z.departmental bulletin pape
