Essays on corporate bond market liquidity and dealer behavior

The thesis consists of three chapters and studies the role of corporate bond dealers as liquidity providers in decentralized over-the-counter markets. The first two empirical chapters explore the impact of dealers' inventory financing constraints on their ability to act as middlemen in corporate bond markets. Specifically, the first chapter provides empirical evidence that dealers' financing constraints are a crucial determinant of the costs of their liquidity provision. The second chapter demonstrates that bonds handled by dealers with higher financing constraints are associated with substantially larger and abrupt price declines and slower price reversals in case of a rating downgrade from investment to non-investment grades. The third theoretical chapter studies the effects of post-trade disclosure on a dealer's dynamic trading strategy in a two-period dealership market and shows that in terms of customer welfare neither a regime with full nor one without post-trade transparency is universally dominating

Spiking neural models & machine learning for systems neuroscience: Learning, Cognition and Behavior.

Learning, cognition and the ability to navigate, interact and manipulate the world around us by performing appropriate behavior are hallmarks of artificial as well as biological intelligence. In order to understand how intelligent behavior can emerge from computations of neural systems, this thesis suggests to consider and study learning, cognition and behavior simultaneously to obtain an integrative understanding. This involves building detailed functional computational models of nervous systems that can cope with sensory processing, learning, memory and motor control to drive appropriate behavior. The work further considers how the biological computational substrate of neurons, dendrites and action potentials can be successfully used as an alternative to current artificial systems to solve machine learning problems. It challenges the simplification of currently used rate-based artificial neurons, where computational power is sacrificed by mathematical convenience and statistical learning. To this end, the thesis explores single spiking neuron computations for cognition and machine learning problems as well as detailed functional networks thereof that can solve the biologically relevant foraging behavior in flying insects. The obtained results and insights are new and relevant for machine learning, neuroscience and computational systems neuroscience. The thesis concludes by providing an outlook how application of current machine learning methods can be used to obtain a statistical understanding of larger scale brain systems. In particular, by investigating the functional role of the cerebellar-thalamo-cortical system for motor control in primates

Determinants of director compensation in two-tier systems: evidence from German panel data

Building on a unique panel data set of German Prime Standard companies for the period 2005-2008, this paper investigates the influencing factors of both director compensation levels and structure, i.e. the probability of performance-based compensation. Drawing on agency theory arguments and previous literature, we analyze a comprehensive group of determinants, including detailed corporate performance, ownership and board characteristics. While controlling for unobserved heterogeneity, we find director compensation to be set in ways consistent with optimal contracting theory. I.e. compensation is systematically structured to mitigate agency conflicts and to encourage effective monitoring. Thus, our results indicate that similar types of agency conflicts exist in the German two-tier setting. --Director Compensation,Corporate Governance,Outside Directors,Two-tier System,Agency Costs

Ponašanje termički modificiranog drva u vanjskim uvjetima primjene – trajnost, abrazija i izgled

Thermally modified timber (TMT) is increasingly offered in Europe as an alternative to preservative treated timber. TMT durability in field tests as well as its moisture sorption behaviour in façade application was determined so as to consider its suitability for outdoor use. Additionally, abrasion and crack-formation of TMT deckings were examined and the optical appearance of a TMT façade was evaluated after 5 years of service. After 7.5 years exposure in ground contact, the various TMT materials tested were classed as “slightly durable” to “not durable” whereas the classification in above ground exposure was “very durable” to “moderately durable”, which was in line with the reduced moisture sorption of TMT in weathered application. Moreover, the TMT-decking showed less abrasion and crack-formation compared to references, though the TMT façade revealed considerable discoloration by weathering. Hence, the suitability of TMT for above ground use is suggested, but a surface treatment is obligatory if discoloration is objectionable.Termički modificirano drvo (TMT) sve se više nudi u Europi kao alternativa kemijski zaštićenom drvu. Za ocjenu prikladnosti TMT-a za vanjsku upotrebu ispitivana je biološka trajnost u vanjskim uvjetima, kao i sorpcija vode u elementima fasade. Dodatno je ispitivana otpornost na abraziju i nastajanje pukotina u TMT podovima, te je napravljen vizualni pregled TMT fasade nakon petogodišnje upotrebe. Nakon 7,5 godina izloženosti u dodiru s tlom, različiti TMT materijali ocijenjeni su kao "slabo otporni" do "neotporni" dok su ocjene tog istog materijala za izlaganje iznad tla bile "vrlo otporno" do "srednje otporno". Dobivene su ocjene, u skladu sa smanjenom sorpcijom vode TMT materijala u vanjskoj upotrebi. Štoviše, TMT podovi pokazali su manju abraziju i pukotine od referentnog drva, iako su TMT elementi fasade pokazali veću diskoloraciju uzrokovanu abiološkom razgradnjom. Dakle, TMT je u vanjskim uvjetima i iznad tla preporučljiv za upotrebu, ali uz obveznu površinsku obradu ako se želi izbjeći diskoloracija

Energy Optimization in NCFET-based Processors

Energy consumption is a key optimization goal for all modern processors. Negative Capacitance Field-Effect Transistors (NCFETs) are a leading emerging technology that promises outstanding performance in addition to better energy efficiency. Thickness of the additional ferroelectric layer, frequency, and voltage are the key parameters in NCFET technology that impact the power and frequency of processors. However, their joint impact on energy optimization has not been investigated yet.In this work, we are the first to demonstrate that conventional (i.e., NCFET-unaware) dynamic voltage/frequency scaling (DVFS) techniques to minimize energy are sub-optimal when applied to NCFET-based processors. We further demonstrate that state-of-the-art NCFET-aware voltage scaling for power minimization is also sub-optimal when it comes to energy. This work provides the first NCFET-aware DVFS technique that optimizes the processor\u27s energy through optimal runtime frequency/voltage selection. In NCFETs, energy-optimal frequency and voltage are dependent on the workload and technology parameters. Our NCFET-aware DVFS technique considers these effects to perform optimal voltage/frequency selection at runtime depending on workload characteristics. Results show up to 90 % energy savings compared to conventional DVFS techniques. Compared to state-of-the-art NCFET-aware power management, our technique provides up to 72 % energy savings along with 3.7x higher performance

Performance of thermally modified timber (TMT) in outdoor application - durability, abrasion and optical appearance

Thermally modified timber (TMT) is increasingly offered in Europe as an alternative to preservative treated timber. TMT durability, infield tests as well as its moisture sorption behaviour in facade application was determined so as to consider its suitability for outdoor use. Additionally, abrasion and crack-formation of TMT deckings were examined and the optical appearance of a TMT facade was evaluated after 5 years of service. After 7.5 years exposure in ground contact, the various TMT materials tested were classed as "slightly durable" to "not durable" whereas the classification in above ground exposure was "very durable" to "moderately, durable", which was in line with the reduced moisture sorption of TMT in weathered application. Moreover, the TMT-decking showed less abrasion and crack-formation compared to references, though the TMT facade revealed considerable discoloration by weathering. Hence, the suitability of TMT for above ground use is suggested, but a surface treatment is obligatory if discoloration is objectionable

Influence on Habitual versus Goal-Directed Decision Making

Different systems for habitual versus goal-directed control are thought to underlie human decision-making. Working memory is known to shape these decision-making systems and their interplay, and is known to support goal- directed decision making even under stress. Here, we investigated if and how decision systems are differentially influenced by breaks filled with diverse everyday life activities known to modulate working memory performance. We used a within-subject design where young adults listened to music and played a video game during breaks interleaved with trials of a sequential two-step Markov decision task, designed to assess habitual as well as goal-directed decision making. Based on a neurocomputational model of task performance, we observed that for individuals with a rather limited working memory capacity video gaming as compared to music reduced reliance on the goal-directed decision-making system, while a rather large working memory capacity prevented such a decline. Our findings suggest differential effects of everyday activities on key decision-making processes

Influences of source conditions on mountain wave penetration into the stratosphere and mesosphere

We present atmospheric gravity wave (GW) measurements obtained by a Rayleigh/Raman lidar at Lauder, New Zealand (45∘ S, 170∘ E) during and after the DEEPWAVE campaign. GW activity and characteristics are derived from 557 hours of high-resolution lidar data recorded between June and November 2014 in an altitude range between 28 and 76 km. In this period, strong GW activity occurred in sporadic intervals lasting a few days. Enhanced stratospheric GW potential energy density is detected during periods with high tropospheric wind speeds perpendicular to New Zealand's Southern Alps. These enhancements are associated with the occurrence of quasi-stationary GW (mountain waves). Surprisingly, the largest response in the mesosphere is observed for conditions with low to moderate lower tropospheric wind speeds (2–12 m/s). On the other hand, large-amplitude mountain waves excited by strong tropospheric forcings often do not reach mesospheric altitudes, either due to wave breaking and dissipation in the stratosphere or refraction away from New Zealand