Better Feature Tracking Through Subspace Constraints

Feature tracking in video is a crucial task in computer vision. Usually, the tracking problem is handled one feature at a time, using a single-feature tracker like the Kanade-Lucas-Tomasi algorithm, or one of its derivatives. While this approach works quite well when dealing with high-quality video and "strong" features, it often falters when faced with dark and noisy video containing low-quality features. We present a framework for jointly tracking a set of features, which enables sharing information between the different features in the scene. We show that our method can be employed to track features for both rigid and nonrigid motions (possibly of few moving bodies) even when some features are occluded. Furthermore, it can be used to significantly improve tracking results in poorly-lit scenes (where there is a mix of good and bad features). Our approach does not require direct modeling of the structure or the motion of the scene, and runs in real time on a single CPU core.Comment: 8 pages, 2 figures. CVPR 201

The matching law

This article introduces the quantitative analysis of choice behavior by describing a number of equations developed over the years to describe the relation between the allocation of behavior under concurrent schedules of reinforcement and the consequences received for alternative responses. Direct proportionality between rate of responding and rate of reinforcement was observed in early studies, suggesting that behavioral output matched environmental input in a mathematical sense. This relation is termed "strict matching," and the equation that describes it is referred to as "the matching law." Later data showed systematic departures from strict matching, and a generalized version of the matching equation is now used to describe such data. This equation, referred to as "the generalized matching equation," also describes data that follow strict matching. It has become convention to refer to either of these equations as "the matching law." Empirical support for the matching law is briefly summarized, as is the applied and practical significance of matching analyses

Dimensionless scaling of heat-release-induced planar shock waves in near-critical CO2

We performed highly resolved one-dimensional fully compressible Navier-Stokes simulations of heat-release-induced compression waves in near-critical CO2. The computational setup, inspired by the experimental setup of Miura et al., Phys. Rev. E, 2006, is composed of a closed inviscid (one-dimensional) duct with adiabatic hard ends filled with CO2 at three supercritical pressures. The corresponding initial temperature values are taken along the pseudo-boiling line. Thermodynamic and transport properties of CO2 in near-critical conditions are modeled via the Peng-Robinson equation of state and Chung's Method. A heat source is applied at a distance from one end, with heat release intensities spanning the range 10^3-10^11 W/m^2, generating isentropic compression waves for values < 10^9 W/m^2. For higher heat-release rates such compressions are coalescent with distinct shock-like features (e.g. non-isentropicity and propagation Mach numbers measurably greater than unity) and a non-uniform post-shock state is present due to the strong thermodynamic nonlinearities. The resulting compression wave intensities have been collapsed via the thermal expansion coefficient, highly variable in near-critical fluids, used as one of the scaling parameters for the reference energy. The proposed scaling applies to isentropic thermoacoustic waves as well as shock waves up to shock strength 2. Long-term time integration reveals resonance behavior of the compression waves, raising the mean pressure and temperature at every resonance cycle. When the heat injection is halted, expansion waves are generated, which counteract the compression waves leaving conduction as the only thermal relaxation process. In the long term evolution, the decay in amplitude of the resonating waves observed in the experiments is qualitatively reproduced by using isothermal boundary conditions.Comment: As submitted to AIAA SciTech 2017, available at http://arc.aiaa.org/doi/pdf/10.2514/6.2017-008

Infant Mortality: Cross Section study of the United State, with Emphasis on Education

On the surface infant mortality is usually thought of as just a unfortunate part of life in what can happen to an individual family, but infant mortality is part of the factors that affect social capital, which can lead back to overall trust in a community. When that trust starts to wither within a community, economic activity will be affected as community members will not behave as they usually do within their given economic boundaries. While social capital is not solely affected by infant mortality, it does show what type of health status an area has. As a community, state, or country becomes “healthier” we usually will see a high quality of life in terms of being able to afford a better lifestyle of all people affected not just a few individuals. “Health is telling us a story about the major influences on the quality of life in modern societies and it is a story which we cannot afford to ignore”. (Wilkinson 1996) How we tie in that health to economic growth is through social capital. Social capital (generalized trust) is positively correlated with GDP growth and is one of many factors in sustaining that growth. (Putnam 1993) A major contribution to that increase in social capital is having a healthy community. Infant mortality has a part of the health component and has a negative correlated effect on GDP growth. Education levels are important factors in reducing infant mortality. Previous authors explored what causes infant mortality to be higher in different regions (i.e. Martinez et al., Song et al. Gisselmann 2005). These authors looked at China, Uruguay, Sweden, and other regions. These authors concluded that education is a main factor, in reducing infant mortality. Gisselmann argues that more years of education is more beneficial for infant mortality rates than higher income levels. This study will look particularly into the United States as a whole, and break down states as individual cross sections. Once it is reestablished with previous literature that infant mortality being reduced is beneficial for the economy, the data itself will look at what reduces infant mortality rates. Each state is thought to have individual characteristics in cultural, religious, social, and other aspects. The study will look into variations of educational attainment levels and income levels. The data will further see within a country whether there is a educational and infant mortality paradox, as well as how much an individual state influences its own infant mortality rate

Reliability Testing of AlGaN/GaN HEMTs Under Multiple Stressors

We performed an experiment on AlGaN/GaN HEMTs with high voltage and high power as stressors. We found that devices tested under high power generally degraded more than those tested under high voltage. In particular, the high-voltage-tested devices did not degrade significantly as suggested by some papers in the literature. The same papers in the literature also suggest that high voltages cause cracks and pits. However, the high-voltage-tested devices in this study do not exhibit cracks or pits in TEM images, while the high-power-tested devices exhibit pits