Work motivation

Wages

Social Robotic Donuts

In order to broaden the design space for social robot design, we created two air-actuated donutshaped social robots: a small uniform silicone version and a more organic latex version. Our intent was to move away from typical human or animal formmimicry, focusing instead on elastic expression, ambiguous form, and playful behaviors. Early studies show the robots provoking curious relationships with these contestational objects, inviting new forms of intriguing communication and interaction

Insights gained from conversations with labor market decision makers

I describe insights into wage dynamics and downward wage rigidity obtained from more than two hundred interviews with businesspeople, labor leaders, and various labor market intermediaries and made in the early 1990s in the Northeast of the United States. I explain the morale explanation for downward rigidity of the pay of existing employees and discuss what morale is, why businesspeople care about it, and why pay cuts damage it. I discuss the origin and nature of pay structures internal to an establishment, the relation between pay at different establishments, and why firms tend to lay off workers rather than cut pay. The findings of the study to be discussed are reported in detail in Truman Bewley, Why Wages Don’t Fall during a Recession. Cambridge, MA: Harvard University Press (1999). JEL Classification: E3, J3, J5wage determination, wage rigidity

Simple Online and Realtime Tracking with a Deep Association Metric

Simple Online and Realtime Tracking (SORT) is a pragmatic approach to multiple object tracking with a focus on simple, effective algorithms. In this paper, we integrate appearance information to improve the performance of SORT. Due to this extension we are able to track objects through longer periods of occlusions, effectively reducing the number of identity switches. In spirit of the original framework we place much of the computational complexity into an offline pre-training stage where we learn a deep association metric on a large-scale person re-identification dataset. During online application, we establish measurement-to-track associations using nearest neighbor queries in visual appearance space. Experimental evaluation shows that our extensions reduce the number of identity switches by 45%, achieving overall competitive performance at high frame rates.Comment: 5 pages, 1 figur

Dissipative Effects on Inertial-Range Statistics at High Reynolds numbers

Using the unique capabilities of the Variable Density Turbulence Tunnel at the Max Planck Institute for Dynamics and Self-Organization, G\"{o}ttingen, we report experimental result on classical grid turbulence that uncover fine, yet important details of the structure functions in the inertial range. This was made possible by measuring extremely long time series of up to $10^{10}$ samples of the turbulent fluctuating velocity, which corresponds to $\mathcal{O}\left(10^5\right)$ large eddy turnover times. These classical grid measurements were conducted in a well-controlled environment at a wide range of high Reynolds numbers from $R_\lambda=110$ up to $R_\lambda=1600$, using both traditional hot-wire probes as well as NSTAP probes developed at Princeton University. We found that deviations from ideal scaling are anchored to the small scales and that dissipation influences the inertial-range statistics at scales larger than the near-dissipation range.Comment: 6 pages, 5 figure

On the Relaxation of Turbulence at High Reynolds Numbers

Turbulent motions in a fluid relax at a certain rate once stirring has stopped. The role of the most basic parameter in fluid mechanics, the Reynolds number, in setting the relaxation rate is not generally known. This paper concerns the high-Reynolds-number limit of the process. In a classical grid-turbulence wind-tunnel experiment that both reached higher Reynolds numbers than ever before and covered a wide range of them ($10^4 < Re = UM/\nu < 5\times10^6$), we measured the relaxation rate with the unprecedented precision of about 2\%. Here $U$ is the mean speed of the flow, $M$ the forcing scale, and $\nu$ the kinematic viscosity of the fluid. We observed that the relaxation rate was Reynolds-number independent, which contradicts some models and supports others

The journey of hydrogen to quantized vortex cores

Nanoscale hydrogen particles in superfluid helium track the motions of quantized vortices. This provides a way to visualize turbulence in the superfluid. Here, we trace the evolution of the hydrogen from a gas to frozen particles migrating toward the cores of quantized vortices. Not only are the intervening processes interesting in their own right, but understanding them better leads to more revealing experiments.Comment: (8 pages, 4 figures