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SOI circuits powered by embedded solar cell

Published in:
2011 IEEE SOI Conf., 3-6 October 2011.

Summary

Solar cells embedded in the SOI substrate were successfully used as the sole energy source to power a ring oscillator fabricated using an ultra-low-power fully depleted SOI process on the same wafer. The speed of the ring oscillator increased with increasing light intensity and showed a fastest oscillation with a 4.5 ns stage delay and 0.26 fJ power-delay product. The maximum power generated by the solar cell was 9.6 mW/cm2 with an efficiency of 11.6%.
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Summary

Solar cells embedded in the SOI substrate were successfully used as the sole energy source to power a ring oscillator fabricated using an ultra-low-power fully depleted SOI process on the same wafer. The speed of the ring oscillator increased with increasing light intensity and showed a fastest oscillation with a...

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Dual polarization radar winter storm studies supporting development of NEXRAD-based aviation hazard products

Summary

The Next Generation Weather Radar (NEXRAD) dual polarization upgrade has begun adding a functional enhancement to classify hydrometeors. MIT Lincoln Laboratory (LL) develops NEXRAD-based weather radar products for Federal Aviation Administration (FAA) weather systems such as Corridor Integrated Weather System (CIWS), Integrated Terminal Weather System (ITWS), and Weather and Radar Processor (WARP). Without dual polarization, those products are limited to providing information on precipitation location and intensity. With dual polarization, LL is now developing new aviation weather products to determine locations of hydrometeor-based hazards. A product for Icing Hazards Level (IHL) is expected to benefit the FAA. LL has partnered with Valparaiso University (VU) in northern Indiana near Chicago since 2008 to study the evolution of winter storms prior to the NEXRAD dual polarization upgrade. VU contributes to the study a C-band dual polarization weather radar, an on-demand local sounding capability, and a surface winter weather verification team. Additionally, the Wolcott, IN wind profiler is about 70 km south within viewing range of the VU radar, and provides information on the fall speeds of the hydrometeors of interest. This resource-rich location has allowed for substantive study of many winter storm types: synoptic, lake effect, and frontal passages. A key to development of the IHL product is the ability to interpret dual polarization radar signatures from the winter microphysical states and precipitation structures. Evolution of the structures is a response to the microphysical water and ice saturation (sub or super) states. The magnitude of the vertical lift may affect the saturation states. Methods to segregate the radar signatures will be important regarding the inferred presence of a supercooled water icing hazard. The blizzard of Feb. 1 and 2, 2011 produced four distinct precipitation periods (snow, sleet, freezing drizzle, and lake effect snow), all of which will be discussed. The paper and presentation will also detail findings from the study of multiple winter storms and how they inform the development of the IHL product.
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Summary

The Next Generation Weather Radar (NEXRAD) dual polarization upgrade has begun adding a functional enhancement to classify hydrometeors. MIT Lincoln Laboratory (LL) develops NEXRAD-based weather radar products for Federal Aviation Administration (FAA) weather systems such as Corridor Integrated Weather System (CIWS), Integrated Terminal Weather System (ITWS), and Weather and Radar...

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On-chip nonlinear digital compensation for RF receiver

Published in:
HPEC 2011: Conf. on High Performance Embedded Computing, 21-22 September 2011.

Summary

A system-on-chip (SOC) implementation is an attractive solution for size, weight and power (SWaP) restricted applications, such as mobile devices and UAVs. This is partly because the individual parts of the system can be designed for a specific application rather than for a broad range of them, like commercial parts usually must be. Co-design of the analog hardware and digital processing further enhances the benefits of SOC implementations by allowing, for example, nonlinear digital equalization to further enhance the dynamic range of a given front-end component. This paper presents the implementation of nonlinear digital compensation for an active anti-aliasing filter, which is part of a low-power homodyne receiver design. The RF front-end circuitry and the digital compensation will be integrated in the same chip. Co-design allows the front-end to be designed with known dynamic range limitations that will later be compensated by nonlinear equalization. It also allows nonlinear digital compensation architectures matched to specific circuits and dynamic range requirements--while still maintaining some flexibility to deal with process variation--as opposed to higher power general purpose designs.
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Summary

A system-on-chip (SOC) implementation is an attractive solution for size, weight and power (SWaP) restricted applications, such as mobile devices and UAVs. This is partly because the individual parts of the system can be designed for a specific application rather than for a broad range of them, like commercial parts...

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Establishing a risk-based separation standard for unmanned aircraft self separation

Published in:
11th AIAA Aviation Technology, Integration, and Operations (ATIO) Conf., 20-22 September 2011.

Summary

Unmanned Aircraft Systems require an ability to sense and avoid other air traffic to gain access to civil airspace and meet requirements in civil aviation regulations. One sense and avoid function is self separation, which requires that aircraft remain well clear. An approach is proposed in this paper to treat well clear as a separation standard, thus posing it as a relative state between aircraft where the risk of collision first reaches an unacceptable level. By this approach, an analytically-derived boundary for well clear can be derived that supports rigorous safety assessment. A preliminary boundary is proposed in both time and distance for the well clear separation standard, and recommendations for future work are made.
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Summary

Unmanned Aircraft Systems require an ability to sense and avoid other air traffic to gain access to civil airspace and meet requirements in civil aviation regulations. One sense and avoid function is self separation, which requires that aircraft remain well clear. An approach is proposed in this paper to treat...

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A field demonstration of the air traffic control Tower Flight Data Manager prototype

Published in:
HFES 2011, Human Factors and Ergonomics Society 55th Annual Mtg., 19-23 September 2011, p. 61-65.

Summary

The development and evaluation process of the Tower Flight Data Manager prototype at Dallas Ft. Worth airport is described. Key results from the first field evaluation are presented, including lessons learned about making electronic flight information acceptable to controllers. Iteration of the field evaluation methods are discussed for practitioner benefit.
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Summary

The development and evaluation process of the Tower Flight Data Manager prototype at Dallas Ft. Worth airport is described. Key results from the first field evaluation are presented, including lessons learned about making electronic flight information acceptable to controllers. Iteration of the field evaluation methods are discussed for practitioner benefit.

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Noncontact optical detection of explosive particles via photodissociation followed by laser-induced fluorescence

Published in:
Opt. Express, Vol. 19, No. 19, 12 September 2011, pp. 18671-18677.

Summary

High-sensitivity (ng/cm2) optical detection of the explosive 2,4,6- trinitrotoluene (TNT) is demonstrated using photodissociation followed by laser-induced fluorescence (PD-LIF). Detection occurs rapidly, within 6 laser pulses (~7 ns each) at a range of 15 cm. Dropcasting is used to create calibrated samples covering a wide range of TNT concentrations; and a correspondence between fractional area covered by TNT and PD-LIF signal strength is observed. Dropcast data are compared to that of an actual fingerprint. These results demonstrate that PD-LIF could be a viable means of rapidly and remotely scanning surfaces for trace explosive residues.
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Summary

High-sensitivity (ng/cm2) optical detection of the explosive 2,4,6- trinitrotoluene (TNT) is demonstrated using photodissociation followed by laser-induced fluorescence (PD-LIF). Detection occurs rapidly, within 6 laser pulses (~7 ns each) at a range of 15 cm. Dropcasting is used to create calibrated samples covering a wide range of TNT concentrations; and...

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Concept of operations for the Integrated Departure Route Planning (IDRP) tool

Published in:
MIT Lincoln Laboratory Report ATC-379

Summary

A concept of operations for the Integrated Departure Route Planner (IDRP) tool is proposed to address issues in the area of departure route management. By combining information about weather and departure demand, IDRP can both identify potential demand/capacity imbalances and recommend a rerouting option, if appropriate. To effectively implement IDRP into the operational environment, a twophase approach is suggested. The first phase appends IDRP functionality onto the CIWS/RAPT platform, combining departure demand information with the convective weather information, creating a live prototype. This initial phase allows a gradual introduction of functionality into an existing display and enables the gathering of operational data to appropriately evolve IDRP to phase 2. The second phase involves introducing airline route preferences, along with any operational improvements discovered during the initial phase.
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Summary

A concept of operations for the Integrated Departure Route Planner (IDRP) tool is proposed to address issues in the area of departure route management. By combining information about weather and departure demand, IDRP can both identify potential demand/capacity imbalances and recommend a rerouting option, if appropriate. To effectively implement IDRP...

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A photon-counting detector for exoplanet missions

Published in:
SPIE Vol. 8151, Techniques and Instrumentation for Detection of Exoplanets V, 5 September 2011, 81510K.

Summary

This paper summarizes progress of a project to develop and advance the maturity of photon-counting detectors for NASA exoplanet missions. The project, funded by NASA ROSES TDEM program, uses a 256x256 pixel silicon Geiger-mode avalanche photodiode (GM-APD) array, bump-bonded to a silicon readout circuit. Each pixel independently registers the arrival of a photon and can be reset and ready for another photon within 100 ns. The pixel has built-in circuitry for counting photo-generated events. The readout circuit is multiplexed to read out the photon arrival events. The signal chain is inherently digital, allowing for noiseless transmission over long distances. The detector always operates in photon counting mode and is thus not susceptible to excess noise factor that afflicts other technologies. The architecture should be able to operate with shot-noise-limited performance up to extremely high flux levels, >106 photons/second/pixel, and deliver maximum signal-to-noise ratios on the order of thousands for higher fluxes. Its performance is expected to be maintained at a high level throughout mission lifetime in the presence of the expected radiation dose.
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Summary

This paper summarizes progress of a project to develop and advance the maturity of photon-counting detectors for NASA exoplanet missions. The project, funded by NASA ROSES TDEM program, uses a 256x256 pixel silicon Geiger-mode avalanche photodiode (GM-APD) array, bump-bonded to a silicon readout circuit. Each pixel independently registers the arrival...

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A new perspective on GMM subspace compensation based on PPCA and Wiener filtering

Published in:
2011 INTERSPEECH, 27-31 August 2011, pp. 145-148.

Summary

We present a new perspective on the subspace compensation techniques that currently dominate the field of speaker recognition using Gaussian Mixture Models (GMMs). Rather than the traditional factor analysis approach, we use Gaussian modeling in the sufficient statistic supervector space combined with Probabilistic Principal Component Analysis (PPCA) within-class and shared across class covariance matrices to derive a family of training and testing algorithms. Key to this analysis is the use of two noise terms for each speech cut: a random channel offset and a length dependent observation noise. Using the Wiener filtering perspective, formulas for optimal train and test algorithms for Joint Factor Analysis (JFA) are simple to derive. In addition, we can show that an alternative form of Wiener filtering results in the i-vector approach, thus tying together these two disparate techniques.
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Summary

We present a new perspective on the subspace compensation techniques that currently dominate the field of speaker recognition using Gaussian Mixture Models (GMMs). Rather than the traditional factor analysis approach, we use Gaussian modeling in the sufficient statistic supervector space combined with Probabilistic Principal Component Analysis (PPCA) within-class and shared...

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Automatic detection of depression in speech using Gaussian mixture modeling with factor analysis

Summary

Of increasing importance in the civilian and military population is the recognition of Major Depressive Disorder at its earliest stages and intervention before the onset of severe symptoms. Toward the goal of more effective monitoring of depression severity, we investigate automatic classifiers of depression state, that have the important property of mitigating nuisances due to data variability, such as speaker and channel effects, unrelated to levels of depression. To assess our measures, we use a 35-speaker free-response speech database of subjects treated for depression over a six-week duration, along with standard clinical HAMD depression ratings. Preliminary experiments indicate that by mitigating nuisances, thus focusing on depression severity as a class, we can significantly improve classification accuracy over baseline Gaussian-mixture-model-based classifiers.
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Summary

Of increasing importance in the civilian and military population is the recognition of Major Depressive Disorder at its earliest stages and intervention before the onset of severe symptoms. Toward the goal of more effective monitoring of depression severity, we investigate automatic classifiers of depression state, that have the important property...

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