The Impact of Agricultural Conservation Easement on House Prices: A New Hedonic Price Model That Incorporates Spatial Autocorrelation and Spatial Heterogeneity

Research Methods/ Statistical Methods,

Notes on Spinoptics in a Stationary Spacetime

In arXiv:1105.5629, equations of the modified geometrical optics for circularly polarized photon trajectories in a stationary spacetime are derived by using a (1+3)-decomposed form of Maxwell's equations. We derive the same results by using a four-dimensional covariant description. In our procedure, the null nature of the modified photon trajectory naturally appears and the energy flux is apparently null. We find that, in contrast to the standard geometrical optics, the inner product of the stationary Killing vector and the tangent null vector to the modified photon trajectory is no longer a conserved quantity along light paths. This quantity is furthermore different for left and right handed photon. A similar analysis is performed for gravitational waves and an additional factor of 2 appears in the modification due to the spin-2 nature of gravitational waves.Comment: 15 pages, to appear in PR

On the modeling of low-Reynolds-number turbulence

A full Reynolds-stress closure that is capable of describing the flow all the way to the wall was formulated for turbulent flow through circular pipe. Since viscosity does not appear explicitly in the pressure redistribution terms, conventional high-number models for these terms are found to be applicable. However, the models for turbulent diffusion and viscous dissipation have to be modified to account for viscous diffusion near a wall. Two redistribution and two diffusion models are investigated for their effects on the model calculations. Wall correction to pressure redistribution modeling is also examined. Diffusion effects on calculated turbulent properties are further investigated by simplifying the transport equations to algebraic equations for Reynolds stress. Two approximations are explored. These are the equilibrium and nonequilibrium turbulence assumptions. Finally, the two-equation closure is also used to calculate the flow in question and the results compared with all the other model calculations. Fully developed pipe flows at two moderate Reynolds numbers are used to validate these model calculations

Judicial Review and the War on Terror

This article examines the role of the federal courts in the war on terrorism, and contrasts the different judicial roles in reviewing decisions about the conduct of war abroad and within the United States. It explains that judicial refusal to adjudicate questions concerning the initiation and conduct of the war abroad is consistent with a narrow view of judicial review and the political question doctrine. Because the Constitution allocates different war powers to the President and Congress, allowing them to shape warmaking through the interaction of these powers, there is no single, constitutionally-required process for making war that requires judicial enforcement. This view has been borne out in practice, as most recently demonstrated in the wars in Afghanistan and Iraq. The paper also reviews the role played by federal courts with regard to the domestic effects of war, particularly when the war involves American citizens as enemies or when operations occur within the territory of the United States itself. It illustrates the wartime role of judicial review by examining cases arising from the current war against the al Qaeda terrorist organization. In the context of surveillance, the federal courts have granted warrants under the Foreign Intelligence Surveillance Act (FISA) using more flexible standards than exist for a normal search warrant, to permit surveillance of terrorist suspects. With American citizens detained as enemy combatants, the courts have entertained habeas corpus petitions, but have followed a deferential standard of scrutiny for the executive branch\u27s war making decisions. These cases show that while the courts have exercised judicial review over the consequences of the decision to go to war, they have adopted a more flexible, deferential standard of review than would apply to normal, peacetime governmental actions, in order to accommodate the imperatives of conducting war. Thus, judicial review may apply to domestic wartime measures, but in a manner that provides options to the political branches for the conduct of the war, rather than simply serving as a negative check on government action

Silicon solar cell process development, fabrication and analysis

Solar cells were fabricated from EFG ribbons dendritic webs, cast ingots by heat exchanger method, and cast ingots by ubiquitous crystallization process. Baseline and other process variations were applied to fabricate solar cells. EFG ribbons grown in a carbon-containing gas atmosphere showed significant improvement in silicon quality. Baseline solar cells from dendritic webs of various runs indicated that the quality of the webs under investigation was not as good as the conventional CZ silicon, showing an average minority carrier diffusion length of about 60 um versus 120 um of CZ wafers. Detail evaluation of large cast ingots by HEM showed ingot reproducibility problems from run to run and uniformity problems of sheet quality within an ingot. Initial evaluation of the wafers prepared from the cast polycrystalline ingots by UCP suggested that the quality of the wafers from this process is considerably lower than the conventional CZ wafers. Overall performance was relatively uniform, except for a few cells which showed shunting problems caused by inclusions

Viscoelastic Behavior of Solid 4^4He

Over the last five years several experimental groups have reported anomalies in the temperature dependence of the period and amplitude of a torsional oscillator containing solid $^4$He. We model these experiments by assuming that $^4$He is a viscoelastic solid--a solid with frequency dependent internal friction. We find that while our model can provide a quantitative account of the dissipation observed in the torsional oscillator experiments, it only accounts for about 10% of the observed period shift, leaving open the possibility that the remaining period shift is due to the onset of superfluidity in the sample.Comment: 4 pages, 3 figure

Rich time series classification using temporal logic

© 2017 MIT Press Journals. All rights reserved. Time series classification is an important task in robotics that is often solved using supervised machine learning. However, classifier models are typically not 'readable' in the sense that humans cannot intuitively learn useful information about the relationship between inputs and outputs. In this paper, we address the problem of rich time series classification where we propose a novel framework for finding a temporal logic classifier specified in a human-readable form. The classifier is represented as a signal temporal logic (STL) formula that is expressive in capturing spatial, temporal and logical relations from a continuous-valued dataset over time. In the framework, we first find a set of representative logical formulas from the raw dataset, and then construct an STL classifier using a treebased clustering algorithm. We show that the framework runs in polynomial time and validate it using simulated examples where our framework is significantly more efficient than the closest existing framework (up to 920 times faster)