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Boise State University

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2011

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Metamorphic Gaasp Buffers For Growth Of Wide-Bandgap Ingap Solar Cells, J. Simon, S. Tomasulo, P. J. Simmonds, M. Romero, M. L. Lee Jan 2011

Metamorphic Gaasp Buffers For Growth Of Wide-Bandgap Ingap Solar Cells, J. Simon, S. Tomasulo, P. J. Simmonds, M. Romero, M. L. Lee

Paul J. Simmonds

GaAsxP1−x graded buffers were grown via solid source molecular beam epitaxy(MBE) to enable the fabrication of wide-bandgap InyGa1−yP solar cells. Tensile-strained GaAsxP1−x buffers grown on GaAs using unoptimized conditions exhibited asymmetric strain relaxation along with formation of faceted trenches, 100–300 nm deep, running parallel to the [011] direction. We engineered a 6 μm thick grading structure to minimize the faceted trench density and achieve symmetric strain relaxation while maintaining a threading dislocation density of ≤106 cm−2. In comparison, compressively-strained graded GaAsxP1−x buffers on …


Aeolian Nutrient Fluxes Following Wildfire In Sagebrush Steppe: Implications For Soil Carbon Storage, N. J. Hasselquist, M. J. Germino, J. B. Sankey, L. J. Ingram, N. F. Glenn Jan 2011

Aeolian Nutrient Fluxes Following Wildfire In Sagebrush Steppe: Implications For Soil Carbon Storage, N. J. Hasselquist, M. J. Germino, J. B. Sankey, L. J. Ingram, N. F. Glenn

Nancy Glenn

Pulses of aeolian transport following fire can profoundly affect the biogeochemical cycling of nutrients in semi-arid and arid ecosystems. Our objective was to determine horizontal nutrient fluxes occurring in the saltation zone during an episodic pulse of aeolian transport that occurred following a wildfire in a semi-arid sagebrush steppe ecosystem in southern Idaho, USA. We also examined how temporal trends in nutrient fluxes were affected by changes in particle sizes of eroded mass as well as nutrient concentrations associated with different particle size classes. In the burned area, total carbon (C) and nitrogen (N) fluxes were as high as 235 …


On Models, Bounds, And Estimation Algorithms For Time-Varying Phase Noise, M. Reza Khanzadi, Hani Mehrpouyan, Erik Alpman, Tommy Svensson, Dan Kuylenstierna, Thomas Eriksson Jan 2011

On Models, Bounds, And Estimation Algorithms For Time-Varying Phase Noise, M. Reza Khanzadi, Hani Mehrpouyan, Erik Alpman, Tommy Svensson, Dan Kuylenstierna, Thomas Eriksson

Hani Mehrpouyan

In this paper, a new discrete-time model of phase noise for digital communication systems, based on a comprehensive continuous-time representation of time-varying phase noise is derived and its statistical characteristics are presented. The proposed phase noise model is shown to be more accurate than the classical Wiener model. Next, using the proposed discrete-time model, the non-data-aided (NDA) and decision-directed (DD) maximum-likelihood (ML) estimators of time-varying phase noise are derived. To evaluate the performance of the proposed estimators, the Cramér-Rao lower bound (CRLB) for each estimation approach is derived and by using Monte-Carlo simulations it is shown that the mean-square error …


A New Distributed Approach For Achieving Clock Synchronization In Heterogeneous Networks, Hani Mehrpouyan, Steven D. Blostein, Tommy Svensson Jan 2011

A New Distributed Approach For Achieving Clock Synchronization In Heterogeneous Networks, Hani Mehrpouyan, Steven D. Blostein, Tommy Svensson

Hani Mehrpouyan

Heterogeneous networks have the potential to improve coverage, throughput, and energy efficiency of wireless networks through the use of specialized cellular structures, in particular femtocells and macrocells. However, to reduce interference between different cells, ensure smooth hand-offs from cell to cell, and achieve seamless operation the overall network needs to be synchronized. In this paper a new distributed clock synchronization scheme for heterogeneous networks is proposed that employs the clock drift information available at user-equipments (UEs) to achieve synchronization between non-interacting femtocells and macrocells. Simulation results show that the proposed scheme can significantly reduce the clock drift between macrocells and …


Optimal And Approximate Methods For Detection Of Uncoded Data With Carrier Phase Noise, Rajet Krishnan, Hani Mehrpouyan, Thomas Eriksson, Tommy Svensson Jan 2011

Optimal And Approximate Methods For Detection Of Uncoded Data With Carrier Phase Noise, Rajet Krishnan, Hani Mehrpouyan, Thomas Eriksson, Tommy Svensson

Hani Mehrpouyan

Previous results in the literature have shown that derivation of the optimum maximum-likelihood (ML) receiver for symbol-by-symbol (SBS) detection of an uncoded data sequence in the presence of random phase noise is an intractable problem, since it involves the computation of the conditional probability distribution function (PDF) of the phase noise process. In this paper, we seek to minimize symbol error probability (SEP), which is achieved by SBS detection of the sequence based on all received signals. We show that the ML detector for this problem can be formulated as a weighted sum of central moments of the conditional PDF …


Moving Forward With Citizen Deliberation: Lessons And Inspiration From The National Citizens' Technology Forum, Jason Delborne, Jen Schneider Jan 2011

Moving Forward With Citizen Deliberation: Lessons And Inspiration From The National Citizens' Technology Forum, Jason Delborne, Jen Schneider

Jen Schneider

In his article on the National Citizens' Technology Forum (NCTF) in this chapter, Cobb notes that the NCTF was essentially a decendant of the "consensus conference," a form of political engagement that originated in Denmark and then traveled elsewhere. Sponsored by the Danish Parliament, the Danish Board of Technology was tasked with involving groups of citizens in making informed policy recommendations related to science and technology: these policy recommendations were and are considered by lawmakers in forming science policy. Cobb and others have noted that the consensus conference and related forms of public engagement have garnered significant academic interest in …


Putting Partnership First: A Dialogue Model For Science And Risk Communication, Jen Schneider, Roel Snieder Jan 2011

Putting Partnership First: A Dialogue Model For Science And Risk Communication, Jen Schneider, Roel Snieder

Jen Schneider

In April 2010, the New York Times reported that Vattenfall AB, an energy company owned by the Swedish government, had built one of the first coal-fired power plants designed to capture ~90% of the CO2 it produced, with plans to sequester that CO2 underground in geologic repositories near its plant in Brandenburg, Germany (Voosen, 2010). By most measures, if the plant's operations were proven to be successful, it could have served as a model for other carbon capture and sequestration plants worldwide.


Ice Rafts Not Sails: Floating The Rocks At Racetrack Playa, Ralph D. Lorenz, Brian K. Jackson, Jason W. Barnes, Joe Spitale, John M. Keller Jan 2011

Ice Rafts Not Sails: Floating The Rocks At Racetrack Playa, Ralph D. Lorenz, Brian K. Jackson, Jason W. Barnes, Joe Spitale, John M. Keller

Brian Jackson

We suggest that the existence of many of the rock-carved trails at Racetrack Playa in Death Valley National Park is predominantly due to the effect of arbitrarily weak winds on rocks that are floated off the soft bed by small rafts of ice, as also occurs in arctic tidal beaches to form boulder barricades. These ice cakes need not have a particularly large surface area if the ice is adequately thick—the ice cakes allow the rocks to move by buoyantly reducing the reaction and friction forces at the bed, not by increasing the wind drag. The parameter space of ice …


Current Patterns Of Variation In Modern Hebrew Spirantization, Michal Martinez Jan 2011

Current Patterns Of Variation In Modern Hebrew Spirantization, Michal Martinez

Michal Temkin Martinez

Modern Hebrew (MH) spirantization is a variable phenomenon with many exceptions. Adam (2002) claims that the variation is driven by these exceptions and concludes that spirantization is changing, yielding what is currently a variable grammar, with equal weight given to expected and variant forms. However, it is not known what the current stage of the grammar looks like. This paper reports the results of an acceptability rating task showing that the expected form is still rated as more acceptable than variant forms, and which variant surfaces (stop or fricative) depends on its underlying root position. MH has three stop/fricative pairs …