Media Upload Prioritization Based on User Preferences

Poor wireless network conditions limit the ability of security cameras and other devices to upload media. Consequently, viewers may not be able to watch video streams in a timely manner. On the other hand, even successfully uploaded media available for viewing is sometimes found to not be of interest to the user. This disclosure describes techniques to determine media segments (e.g., live video captured by a camera) likely of greatest interest to viewers and prioritize the uploading of those segments. The criteria for uploading or storing media under poor network conditions are selected to optimize the user experience on a best-effort basis. When network connectivity is limited, uploaded segments (and the order of uploading) match the current interests of the users. When device storage is full, segments to be discarded (and the order of discarding) are of least interest to the user. The described techniques of prioritized media upload and retry/discard strategies optimize user experience under poor network conditions such as frequent network outage, low available bandwidth, unstable network connection, etc

Improving Access to Clean Water Through Autonomous Monitoring of Hand Pump Operation

Millions of people in developing countries rely on hand pumps for access to clean water. Proper maintenance of these pumps is impossible without timely reporting on the pump’s operation and state of repair. The Intelligent Water System, which improves access to clean water by autonomously monitoring and reporting on the health of hand pumps, has been under development for several years. The next stage for the IWP team is to prepare for field testing in Zimbabwe. Because of this, the team has been working on improving the accuracy of the calculations made by the Intelligent Water System as well as simplifying the installation procedures to allow installation by in-country pump technicians. This poster shows the progress made by the IWP team during this stage of development including the improvements in the volume calculation algorithm as well as the installation jig and procedures. Funding for this work provided by The Collaboratory for Strategic Partnerships and Applied Research.https://mosaic.messiah.edu/engr2022/1008/thumbnail.jp

Detection of intrinsic source structure at ~3 Schwarzschild radii with Millimeter-VLBI observations of SAGITTARIUS A*

We report results from very long baseline interferometric (VLBI) observations of the supermassive black hole in the Galactic center, Sgr A*, at 1.3 mm (230 GHz). The observations were performed in 2013 March using six VLBI stations in Hawaii, California, Arizona, and Chile. Compared to earlier observations, the addition of the APEX telescope in Chile almost doubles the longest baseline length in the array, provides additional {\it uv} coverage in the N-S direction, and leads to a spatial resolution of $\sim$30 $\mu$as ($\sim$3 Schwarzschild radii) for Sgr A*. The source is detected even at the longest baselines with visibility amplitudes of $\sim$4-13% of the total flux density. We argue that such flux densities cannot result from interstellar refractive scattering alone, but indicate the presence of compact intrinsic source structure on scales of $\sim$3 Schwarzschild radii. The measured nonzero closure phases rule out point-symmetric emission. We discuss our results in the context of simple geometric models that capture the basic characteristics and brightness distributions of disk- and jet-dominated models and show that both can reproduce the observed data. Common to these models are the brightness asymmetry, the orientation, and characteristic sizes, which are comparable to the expected size of the black hole shadow. Future 1.3 mm VLBI observations with an expanded array and better sensitivity will allow a more detailed imaging of the horizon-scale structure and bear the potential for a deep insight into the physical processes at the black hole boundary.Comment: 11 pages, 5 figures, accepted to Ap

Endogenous Constitutions: Politics and Politicians Matter, Economic Outcomes Don’t

We study changes in the form of government as an example of endogenously determined constitutions. For a sample of 202 countries over the period 1950-2006, we find that most changes are relatively small and roughly equally likely to be either in the direction of more parliamentarian or more presidential systems. Based on a fixed effects ordered logit panel data model estimated over the period 1951-2000 for 146 countries, we find that such changes in the constitution can be explained by characteristics of the political system, internal and external political conflicts, and political leaders, whereas economic and socio-demographic variables do not matter

Persistent Asymmetric Structure of Sagittarius A* on Event Horizon Scales

The Galactic Center black hole Sagittarius A* (Sgr A*) is a prime observing target for the Event Horizon Telescope (EHT), which can resolve the 1.3 mm emission from this source on angular scales comparable to that of the general relativistic shadow. Previous EHT observations have used visibility amplitudes to infer the morphology of the millimeter-wavelength emission. Potentially much richer source information is contained in the phases. We report on 1.3 mm phase information on Sgr A* obtained with the EHT on a total of 13 observing nights over 4 years. Closure phases, the sum of visibility phases along a closed triangle of interferometer baselines, are used because they are robust against phase corruptions introduced by instrumentation and the rapidly variable atmosphere. The median closure phase on a triangle including telescopes in California, Hawaii, and Arizona is nonzero. This result conclusively demonstrates that the millimeter emission is asymmetric on scales of a few Schwarzschild radii and can be used to break 180-degree rotational ambiguities inherent from amplitude data alone. The stability of the sign of the closure phase over most observing nights indicates persistent asymmetry in the image of Sgr A* that is not obscured by refraction due to interstellar electrons along the line of sight.Astronom