Representation of perfectly reconstructed octave decomposition filter banks with set of decimators {2,4,4} via tree structure

In this letter, we prove that a filter bank with set of decimators {2,4,4} achieves perfect reconstruction if and only if it can be represented via a tree structure and each branch of the tree structure achieves perfect reconstruction

Delaunay Edge Flips in Dense Surface Triangulations

Delaunay flip is an elegant, simple tool to convert a triangulation of a point set to its Delaunay triangulation. The technique has been researched extensively for full dimensional triangulations of point sets. However, an important case of triangulations which are not full dimensional is surface triangulations in three dimensions. In this paper we address the question of converting a surface triangulation to a subcomplex of the Delaunay triangulation with edge flips. We show that the surface triangulations which closely approximate a smooth surface with uniform density can be transformed to a Delaunay triangulation with a simple edge flip algorithm. The condition on uniformity becomes less stringent with increasing density of the triangulation. If the condition is dropped completely, the flip algorithm still terminates although the output surface triangulation becomes "almost Delaunay" instead of exactly Delaunay.Comment: This paper is prelude to "Maintaining Deforming Surface Meshes" by Cheng-Dey in SODA 200

Designs of low delay cosine modulated filter banks and subband amplifiers

This paper proposes a design of a low delay cosine modu-lated filter bank and subband amplifier coefficients for digi-tal audio hearing aids denoising applications. The objective of the design is to minimize the delay of the filter bank. Speci-fications on the maximum magnitude of both the real and the imaginary parts of the transfer function distortion and the aliasing distortion of the filter bank are imposed. Also, the constraint on the maximum absolute difference between the desirable magnitude square response and the designed mag-nitude square response of the prototype filter over both the passband and the stopband is considered. The subband am-plifier coefficients are designed based on a least squares training approach. The average mean square errors between the noisy samples and the clean samples is minimized. Com-puter numerical simulation results show that our proposed approach could significantly improve the signal-to-noise ratio of digital audio hearing aids

Notes on the early-type components of W Cep, o Cet, CH Cyg, AR Mon, and BL Tel

Low resolution IUE spectra in both spectral regions are used to clarify the nature of the warmer components of several binary systems. The W Cep, the primary of which is a luminous K-type supergiant, shows an ultraviolet absorption spectrum of type B0 or B1; this system is heavily reddened. The hot companion of Mira (o Cet) is surprisingly faint in the short wavelength region, but it excites a rich emission spectrum from the surrounding gas. The ultraviolet active M7 giant CH Cyg is shown to be a binary with a hot companion. This system was also observed at high resolution and shows variable Fe II emission and well-separated circumstellar and interstellar absorptions within the broad Mg II emission profiles. The eclipsing binaries AR Mon and BL Tel are shown not to have hot companions

Cities, traffic, and CO2: A multidecadal assessment of trends, drivers, and scaling relationships

Emissions of CO2 from road vehicles were 1.57 billion metric tons in 2012, accounting for 28% of US fossil fuel CO2 emissions, but the spatial distributions of these emissions are highly uncertain. We develop a new emissions inventory, the Database of Road Transportation Emissions (DARTE), which estimates CO2 emitted by US road transport at a resolution of 1 km annually for 1980-2012. DARTE reveals that urban areas are responsible for 80% of on-road emissions growth since 1980 and for 63% of total 2012 emissions. We observe nonlinearities between CO2 emissions and population density at broad spatial/temporal scales, with total on-road CO2 increasing nonlinearly with population density, rapidly up to 1,650 persons per square kilometer and slowly thereafter. Per capita emissions decline as density rises, but at markedly varying rates depending on existing densities. We make use of DARTE's bottom-up construction to highlight the biases associated with the common practice of using population as a linear proxy for disaggregating national- or state-scale emissions. Comparing DARTE with existing downscaled inventories, we find biases of 100% or more in the spatial distribution of urban and rural emissions, largely driven by mismatches between inventory downscaling proxies and the actual spatial patterns of vehicle activity at urban scales. Given cities' dual importance as sources of CO2 and an emerging nexus of climate mitigation initiatives, high-resolution estimates such as DARTE are critical both for accurately quantifying surface carbon fluxes and for verifying the effectiveness of emissions mitigation efforts at urban scales.https://doi.org/10.1073/pnas.1421723112Published versio

EVOLUTION OF DOLLAR/EURO EXCHANGE RATE BEFORE AND AFTER THE BIRTH OF EURO AND POLICY IMPLICATIONS

One possible consequence of the establishment of the Euro is a challenge to the hegemony of the US dollar as the predominant international currency. No other currency has been able to rival the international role of the national currency of the US since World War II. The fact that the unipolar international monetary system can be unstable in the presence of large shocks opens a window of opportunity for the Euro to promote systemic stability. The present study pursues this conjecture by, first, exploring with cointegration and ECM techniques the interdependence between the dynamics of the Dollar/Euro exchange rate and economic fundamentals in the context of a monetary exchange rate model. Identification of the key determinants of the value of the Euro informs our analysis of the policy stance of the European Central Bank regarding the long-run global role of the Euro. Secondly, we explore whether the opportunity for a prominent systemic role of the Euro has been realized by examining the impact of the Euro on the global financial market.Euro, Exchange rate, Monetary model, Cointegration

Strong Coupling Superconductivity in the Vicinity of the Structural Quantum Critical Point in (CaxSr1-x)3Rh4Sn13

The family of the superconducting quasiskutterudites (CaxSr1?x)3Rh4Sn13 features a structural quantum critical point at xc=0.9, around which a dome-shaped variation of the superconducting transition temperature Tc is found. Using specific heat, we probe the normal and the superconducting states of the entire series straddling the quantum critical point. Our analysis indicates a significant lowering of the effective Debye temperature on approaching xc, which we interpret as a result of phonon softening accompanying the structural instability. Furthermore, a remarkably large enhancement of 2?/kBTc and ?C/?Tc beyond the Bardeen-Cooper-Schrieffer values is found in the vicinity of the structural quantum critical point. The phase diagram of (CaxSr1?x)3Rh4Sn13 thus provides a model system to study the interplay between structural quantum criticality and strong electron-phonon coupling superconductivity

Optimal two-stage filtering of elastograms

In ultrasound elastography, tissue axial strains are obtained through the differentiation of measured axial displacements. However, during the measurement process, the displacement signals are often contaminated with de-correlation noise caused by changes in the speckle pattern in the tissue. Thus, the application of the gradient operator on the displacement signals results in the presence of amplified noise in the axial strains, which severely obscures the useful information. The use of an effective denoising scheme is therefore imperative. In this paper, a method based on a two-stage consecutive filtering approach is proposed for the accurate estimation of axial strains. The presented method considers a cascaded system of a frequency filter and a time window, which are both designed such that the overall system operates optimally as a minimum variance estimator. Experimentation on simulated signals shows that the two-stage scheme employed in this study has good potential as a denoising method for ultrasound elastograms

Building a Frameworks for Apron Planning, Design, Optimization, Future Proofing and Expansion

Airports are a significant economic driver that impact local and national interests. As such, in an ever connected world, these critical components of infrastructure face a growing number of influences which contribute to systems complexity and frequently impede further development. The point of this dissertation is to discuss and highlight the benefit of systematic thinking as planners approach airport planning challenges and update the aging aviation infrastructure in many regions of the world. This dissertation looks at a series of three papers that, examine the impact and influences of technology, distinguishes the effects of social and procedural changes, and offers one solution to simplify systems planning and integration within the aviation industry. The first paper presented is an examination of the history of Pan American World Airways through a data centered look at the growth of the fleet. The second paper examines some of the current and impending risk broken into categories, based on an examination of socio-technical systems. The final paper offers a solution a new system that could be constructed at an airport, which could simplify an aircraft turn around xiv process and help future proof airports for some of the expected changes that will impact the aviation industry. The solution proposed in CHAPTER V offers an example of a systemic change to the development of the apron area. This new concept integrates most of the apron area systems into a single system for aircraft loading and unloading. This work shows the need to accommodate industry changes as they develop, and clearly identifies some of the most obvious challenges and risks that face the aviation industry. This work further offers one method for solving and avoiding the costly interventions usually required to overhaul a system when emergent behavior necessitates a physical change to the infrastructure of the system. As with the development of any dissertation, much of this document has been updated and improved actively throughout this process. While this is a final document there is always more that can be added. This provided a complete overview of the apron area though and provides a clear contribution to the aviation industry