Perception of Waiting Time at Signalized Intersections

Perceived waiting time at signalized intersections differs from the real value, and varies with signal design. The onerousness of delay depends on the conditions under which it is experienced. Using weighted travel time time may contribute to optimal signal control if its use can improve upon assuming that all time is weighted equally by users. This research explores the perception of waiting time at signalized intersections based on the results of an online survey, which directly collected the perceived waiting time and the user ratings of the signal designs of each intersection on an arterial including 3 intersections. Statistically analyzing the survey data suggests the perception of waiting time is a function of the real time; and a quadratic model better can describes relationship. The survey also indicates that there exists a tradeoff between the total waiting time and the individual waiting time of each intersection. It turns out that drivers prefer to split the total waiting time at different intersections at the price of a longer total wait if the difference of the total waiting time of two signal designs is within 30 seconds. The survey data shows that the perceived waiting time, instead of the real waiting time, better explains how users will rate the individual signal designs for both intersections and arterials including multiple intersections.Traffic Signal, Stated Preference, Virtual Experience Stated Preference, Signalized Intersection, Value of Time, Perception of Time

IPO Performance and the Size Effect: Evidence for the US and Canada

This study investigates the interaction between firm size and IPO underpricing in the US and Canadian markets between the years 2007-2016. We find a size effect on IPO underpricing in both Canada and the US, which is larger for Canadian firms. Canadian small firms show more underpricing than US small firms (19.32% vs. 13.87%). Large Canadian firms also exhibit more underpricing than their US counterparts over the sample period (12.83% vs. 10.09%). A size effect on performance is not apparent for holding periods beyond six months from the IPO in both countries, consistent with seasoning effects that reduce information asymmetries across firms over longer investment horizons. Keyword: IPO performance; size effects; short-term information asymmetrie

Surface Engineering for Molecular Electronics

Molecular electronics studies charge transport through molecules and the applications in electronic devices where molecules serve as the ultimate nanosized building blocks. Controllable charge transport properties and stable electrical junctions lie at the heart of molecular electronics because of their crucial impact on practical devices, and both of them concern engineering at the surface and interface, e.g., anchoring functional molecules onto electrodes and forming densely packed monolayers resistive against electrostatic pressure. This thesis aims to unite the synthesis and characterization of functional (bio)organic semiconductive molecular self-assemblies and the fabrication of electronic devices comprising these ensembles for paradigm-shifting applications from a surface engineering perspective

Topological Disorder Operators in Three-Dimensional Conformal Field Theory

Many abelian gauge theories in three dimensions flow to interacting conformal field theories in the infrared. We define a new class of local operators in these conformal field theories which are not polynomial in the fundamental fields and create topological disorder. They can be regarded as higher-dimensional analogues of twist and winding-state operators in free 2d CFTs. We call them monopole operators for reasons explained in the text. The importance of monopole operators is that in the Higgs phase, they create Abrikosov-Nielsen-Olesen vortices. We study properties of these operators in three-dimensional QED using large N_f expansion. In particular, we show that monopole operators belong to representations of the conformal group whose primaries have dimension of order N_f. We also show that monopole operators transform non-trivially under the flavor symmetry group, with the precise representation depending on the value of the Chern-Simons coupling.Comment: 24 pages, latex. v2: a reference to prior work has been adde

Rethinking Sampled-Data Control for Unmanned Aircraft Systems

Unmanned aircraft systems are expected to provide both increasingly varied functionalities and outstanding application performances, utilizing the available resources. In this paper, we explore the recent advances and challenges at the intersection of real-time computing and control and show how rethinking sampling strategies can improve performance and resource utilization. We showcase a novel design framework, cyber-physical co-regulation, which can efficiently link together computational and physical characteristics of the system, increasing robust performance and avoiding pitfalls of event-triggered sampling strategies. A comparison experiment of different sampling and control strategies was conducted and analyzed. We demonstrate that co-regulation has resource savings similar to event-triggered sampling, but maintains the robustness of traditional fixed-periodic sampling forming a compelling alternative to traditional vehicle control design