Evidence for Charging Effects in CdTe/CdMgTe Quantum Point Contacts

Here we report on fabrication and low temperature magnetotransport measurements of quantum point contacts patterned from a novel two-dimensional electron system - CdTe/CdMgTe modulation doped heterostructure. From the temperature and bias dependence we ascribe the reported data to evidence for a weakly bound state which is naturally formed inside a CdTe quantum constrictions due to charging effects. We argue that the spontaneous introduction of an open dot is responsible for the replacement of flat conductance plateaus by quasi-periodic resonances with amplitude less than 2e^{2}/h, as found in our system. Additionally, below 1 K a pattern of weaker conductance peaks, superimposed upon wider resonances, is also observed.Comment: 4 pages, 4 figure

Low-effort place recognition with WiFi fingerprints using deep learning

Using WiFi signals for indoor localization is the main localization modality of the existing personal indoor localization systems operating on mobile devices. WiFi fingerprinting is also used for mobile robots, as WiFi signals are usually available indoors and can provide rough initial position estimate or can be used together with other positioning systems. Currently, the best solutions rely on filtering, manual data analysis, and time-consuming parameter tuning to achieve reliable and accurate localization. In this work, we propose to use deep neural networks to significantly lower the work-force burden of the localization system design, while still achieving satisfactory results. Assuming the state-of-the-art hierarchical approach, we employ the DNN system for building/floor classification. We show that stacked autoencoders allow to efficiently reduce the feature space in order to achieve robust and precise classification. The proposed architecture is verified on the publicly available UJIIndoorLoc dataset and the results are compared with other solutions

The Distributed Electronic Load Controller: A New Concept for Voltage Regulation in Microhydro Systems with Transfer of Excess Power to Households

AbstractConstant voltage and frequency can be generated by a stand-alone Self-Excited Induction Generator (SEIG) driven with a fixed-speed low-head hydro-turbine when the electrical load is maintained constant by an Electronic Load Controller (ELC). In a Conventional-ELC (C-ELC), usually a chopper with a dump load is used in parallel with the consumer loads to provide regulation of voltage and control of frequency. However, in the C-ELC configuration excess generated power may be wasted in a dump load. The objective of this research is to design a simplified ELC for each household to transfer the excess power for domestic consumption in addition to providing voltage regulation. Hence, a new ELC topology is proposed. This topology can be split into two parts. The first part is a regular ELC of low rated power, which should be installed at the generator site and it is responsible for precise voltage and frequency regulation and dealing with unexpected failure conditions. The second one is a simplified and inexpensive ELC which is installed in each household to direct excess power to a low wattage household apparatus in addition to participation in voltage regulation by maintaining constancy of the load power. This concept is referred to here as the Distributed ELC (DELC). One significant advantage of the proposed DELC approach is that the excess power can be utilized for domestic hot water purposes, and possibly resulting in health benefits related to improved sanitation. Moreover, the proposed topology shows more reliability compared with the C-ELC. Simulation results demonstrate that even with unbalanced three-phase loads (assisted with bi-directional switches per-phase), the proposed topology has the capability to regulate voltage from no-load to full load. Moreover, in the case of a failure in the power switches or the control circuits, the DELC has more reliable performance than a C-ELC

The prospects for coastal residential development under the Cape Cod Commission stewardship

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Architecture, 1994.Includes bibliographical references (leaves 108-109).by Thomas P. Nowicki.M.S

Mortgage Crisis: Exploring Incentives Prevalent During the Boom and Bust of the 2001–2007 Mortgage Market

The purpose of this thesis is to explain the mortgage market\u27s behavior from 2001 through the first quarter of 2007 by discussing the economic incentives key market participants faced. By exploring incentives faced by key participants, a multifaceted yet logical explanation for the aggressive economic expansion and contraction appears. Throughout this paper I argue that the simultaneous acting upon of such incentives was fundamental to the market behavior and that the actions of each participant are, for the most part, understandable given the incentives that each faced. The paper will describe the monetary and cultural incentives underlying this behavior and show how they pertain to the macroeconomic context of the time and to the mortgage crisis. While the incentives discussed in this paper do not comprise an exhaustive list, they sufficiently cover the most vital influences. Most importantly, this thesis does not attempt to find one factor to be more important than another

Motion analysis of elite Polish soccer goalkeepers throughout a season

The study aims were to determine the distance covered by goalkeepers during matches in the context of game duration and result, to identify the area of their most frequent activity, and to assess goalkeepers' involvement in games finished with a win, draw, or loss. The investigation was based on two innovative tools: the goalkeeper's activity index (GAI) and an analysis of 5-min periods. A video tracking system was used to monitor 17 goalkeepers from Polish National League teams during 15 matches. The GAI was applied to assess their involvement in the game. Elite goalkeepers covered 72.7%, 25.8%, and 2.5% of the distance during the game by walking/jogging, running, and sprinting, respectively. The distances covered in lost, won, and drawn matches turned out similar (mean \ub1 SD: 4800 \ub1 906 m, 4696 \ub1 1033 m, and 4660 \ub1 754 m, respectively). There were no significant differences between the distances covered in the first and second halves. The area of most frequent activity was the middle sector of the penalty area between the goal and penalty area lines. ANOVA results showed that in drawn matches, goalkeepers' activity significantly differed in mean values of the GAI in comparison with that in won and lost games (p = 0.034, p = 0.039, respectively). It was noted that goalkeepers tended to intervene more often in games where their team was winning rather than in those with a losing result. Their direct involvement in defending the goal was the lowest in drawn games

Simulated Greenland Surface Mass Balance in the GISS ModelE2 GCM: Role of the Ice Sheet Surface

The rate of growth or retreat of the Greenland and Antarctic ice sheets remains a highly uncertain component of future sea level change. Here we examine the simulation of Greenland ice sheet surface mass balance (GrIS SMB) in the NASA Goddard Institute for Space Studies (GISS) ModelE2 General Circulation Model (GCM). GCMs are often limited in their ability to represent SMB compared with polarregion Regional Climate Models (RCMs). We compare ModelE2 simulated GrIS SMB for presentday (19962005) simulations with fixed ocean conditions, at a spatial resolution of 2 latitude by 2.5 longitude (~200 km), with SMB simulated by the Modle Atmosphrique Rgionale (MAR) RCM (19962005 at a 25 km resolution). ModelE2 SMB agrees well with MAR SMB on the whole, but there are distinct spatial patterns of differences and large differences in some SMB components. The impact of changes to the ModelE2 surface are tested, including a subgridscale representation of SMB with surface elevation classes. This has a minimal effect on ice sheetwide SMB, but corrects local biases. Replacing fixed surface albedo with satellitederived values and an agedependent scheme has a larger impact, increasing simulated melt by 60100%. We also find that lower surface albedo can enhance the effects of elevation classes. Reducing ModelE2 surface roughness length to values closer to MAR reduces sublimation by ~50%. Further work is required to account for meltwater refreezing in ModelE2, and to understand how differences in atmospheric processes and model resolution influence simulated SMB

Development of a telescope for medium-energy gamma-ray astronomy

The Advanced Energetic Pair Telescope (AdEPT) is being developed at GSFC as a future NASA MIDEX mission to explore the medium-energy (5–200 MeV) gamma-ray range. The enabling technology for AdEPT is the Three- Dimensional Track Imager (3-DTI), a gaseous time projection chamber. The high spatial resolution 3-D electron tracking of 3-DTI enables AdEPT to achieve high angular resolution gamma-ray imaging via pair production and triplet production (pair production on electrons) in the medium-energy range. The low density and high spatial resolution of 3-DTI allows the electron positron track directions to be measured before they are dominated by Coulomb scattering. Further, the significant reduction of Coulomb scattering allows AdEPT to be the first medium-energy gamma-ray telescope to have high gamma-ray polarization sensitivity. We review the science goals that can be addressed with a medium-energy pair telescope, how these goals drive the telescope design, and the realization of this design with AdEPT. The AdEPT telescope for a future MIDEX mission is envisioned as a 8 m3 active volume filled with argon at 2 atm. The design and performance of the 3-DTI detectors for the AdEPT telescope are described as well as the outstanding instrument challenges that need to be met for the AdEPT mission

Distance Measurement and κ\kappa-Deformed Propagation of Light and Heavy Probes

We investigate the implications for the measurability of distances of a covariant dimensionful ``$\kappa$'' deformation of D=4 relativistic symmetries, with quantum time coordinate and modified Heisenberg algebra. We show that the structure of the deformed mass-shell condition has significant implications for measurement procedures relying on light probes, whereas in the case of heavy probes the most sizeable effect is due to the nontrivial commutation relation between three-momenta and quantum time coordinate. We argue that these findings might indicate that $\kappa$-Poincar\'e symmetries capture some aspects of the physics of the Quantum-Gravity vacuum.Comment: 13 pages, Latex, to appear in Int. J. Mod. Phys.