Publications

Refine Results

(Filters Applied) Clear All

En route sector capacity model final report

Author:
Published in:
MIT Lincoln Laboratory Report ATC-426

Summary

Accurate predictions of en route sector capacity are vital when analyzing the benefits of proposed new air traffic management decision-support tools or new airspace designs. Controller workload is the main determinant of sector capacity. This report describes a new workload-based capacity model that improves upon the Federal Aviation Administration's current Monitor Alert capacity model. Analysts often use Monitor Alert sector capacities in evaluating the benefits of decision-support aids or airspace designs. However, Monitor Alert, which was designed to warn controllers of possible sector overload, sets sector capacity limits based solely on handoff workload and fixed procedural constraints. It ignores the effects of conflict workload and recurring workload (from activities such as monitoring, vectoring, spacing, and metering). Each workload type varies differently as traffic counts and airspace designs are changed. When used for benefits analysis, Monitor Alert's concentration on a single workload type can lead to erroneous conclusions. The new model considers all three workload types. We determine the relative contribution of the three workload types by fitting the model to the upper frontiers that appear in peak daily sector traffic counts from today's system. When we fit the Monitor Alert model to these same peak traffic counts, it can only explain the observed frontiers by hypothesizing large handoff workload. Large handoff workload would imply that decision-support aids should focus on handoff tasks. The new model fits the traffic data with less error, and shows that recurring tasks create significantly more workload in all sectors than do handoff tasks. The new model also shows that conflict workload dominates in very small sectors. These findings suggest that it is more beneficial to develop decision-support aids for recurring tasks and conflict tasks than for handoff tasks.
READ LESS

Summary

Accurate predictions of en route sector capacity are vital when analyzing the benefits of proposed new air traffic management decision-support tools or new airspace designs. Controller workload is the main determinant of sector capacity. This report describes a new workload-based capacity model that improves upon the Federal Aviation Administration's current...

READ MORE

D4M and large array databases for management and analysis of large biomedical imaging data

Summary

Advances in medical imaging technologies have enabled the acquisition of increasingly large datasets. Current state-of-the-art confocal or multi-photon imaging technology can produce biomedical datasets in excess of 1 TB per dataset. Typical approaches for analyzing large datasets rely on downsampling the original datasets or leveraging distributed computing resources where small subsets of images are processed independently. These approaches require significant overhead on the part of the programmer to load the desired sub-volume from an array of image files into memory. Databases are well suited for indexing and retrieving components of very large datasets and show significant promise for the analysis of 3D volumetric images. In particular, array-based databases such as SciDB utilize an architecture that supports massive parallel processing while also providing database services such as data management and fast parallel queries. In this paper, we will present a new set of tools that leverage the D4M (Dynamic Distributed Dimensional Data Model) toolbox for analyzing giga-voxel biomedical datasets. By combining SciDB and the D4M toolbox, we demonstrate that we can access large volumetric data and perform large-scale bioinformatics analytics efficiently and interactively. We show that it is possible to achieve an ingest rate of 2.8 million entries per second for importing large datasets into SciDB. These tools provide more efficient ways to access random sub-volumes of massive datasets and to process the information that typically cannot be loaded into memory. This work describes the D4M and SciDB tools that we developed and presents the initial performance results.
READ LESS

Summary

Advances in medical imaging technologies have enabled the acquisition of increasingly large datasets. Current state-of-the-art confocal or multi-photon imaging technology can produce biomedical datasets in excess of 1 TB per dataset. Typical approaches for analyzing large datasets rely on downsampling the original datasets or leveraging distributed computing resources where small...

READ MORE

Comb generator design for SWaP-constrained applications

Published in:
2016 IEEE Radio and Wireless Symp., RWS 2016, 24-27 January 2016.

Summary

Many wireless devices have requirements that emphasize low size, weight and power for increased functionality and extended lifetimes. The additional complexity of these devices mandates the need to dynamically verify that all sub-system functions are fully operational. These tests can only be performed internal to the unit, and a circuit that could be utilized to meet this demand should be constructed to be as simple as possible. This paper presents both a novel set of equations to represent a compact comb generator circuit using a step recovery diode as well as unique sequential measurements of a prototype to provide greater insight into the design. The analyzed circuit requires no bias voltage, and effectively produces harmonics up to 2 GHz with a 2 MHz input signal, which is sufficient for adding built-in-test capability to most wireless devices.
READ LESS

Summary

Many wireless devices have requirements that emphasize low size, weight and power for increased functionality and extended lifetimes. The additional complexity of these devices mandates the need to dynamically verify that all sub-system functions are fully operational. These tests can only be performed internal to the unit, and a circuit...

READ MORE

Simultaneous Transmit and Receive (STAR) mobile testbed

Published in:
2016 IEEE Radio and Wireless Symp., RWS 2016, 24-27 January 2016.

Summary

Simultaneous Transmit and Receive (STAR) systems typically utilize multiple cancellation layers to improve system isolation and avoid self-interference. The design of these different layers must be evaluated both individually and as a whole to determine their effectiveness in various environments. A flexible and reusable mobile testbed was constructed to aid in the development and assessment of these different STAR technologies for both stationary and non-stationary applications. The usefulness of this platform was confirmed during the integration of an example STAR system that measured greater than 100 dB of total system isolation over a 30 MHz bandwidth centered at 2.45 GHz.
READ LESS

Summary

Simultaneous Transmit and Receive (STAR) systems typically utilize multiple cancellation layers to improve system isolation and avoid self-interference. The design of these different layers must be evaluated both individually and as a whole to determine their effectiveness in various environments. A flexible and reusable mobile testbed was constructed to aid...

READ MORE

Reagent approaches for improved detection of chlorate and perchlorate salts via thermal desorption and ionization

Published in:
Rapid Commun. Mass Spectrom., Vol. 30, No. 1, 15 January 2016, pp. 191-8, DOI: 10.1002/rcm.7427.

Summary

RATIONALE: Techniques for improving the detectability of chlorate and perchlorate salts with thermal desorption based ionizers (i.e. radioactive, corona discharge and photoionization-based) are desired. This work employs acidic reagents to chemically transform chlorate and perchlorate anions into traces of chloric and perchloric acid. These high vapor pressure acids are easier to detect than the originating salts. METHODS: The efficacy of the reagent chemistry was quantified with a triple-quadrupole mass spectrometer interfaced with a custom-built thermal-desorption atmospheric-pressure chemical ionization (TD-APCI) source. Additional experiments were conducted using tandem IMS/MS instrumentation. Reagent pKa and pH values were varied in order to gain a better understanding of how those parameters affect the degree of observed signal enhancement. RESULTS: Samples of chlorates and perchlorates treated with liquid acidic reagents exhibit signal enhancement of up to six orders of magnitude compared with signals from untreated analytes. Three orders of magnitude of signal enhancement are demonstrated using solid-state reagents, such as weakly acidic salts and polymeric acids. Data is presented that demonstrates the compatibility of the solid-state approach with both MS and IMS/MS platforms. CONCLUSIONS: Several methods of acidification were demonstrated for enhanced vaporization and detection of chlorates and perchlorates. For applications where rapid surface collection and analysis for chlorates and perchlorates are desired, the solid-state approaches offer the simplest means to integrate the reagent chemistry into MS or IMS detection.
READ LESS

Summary

RATIONALE: Techniques for improving the detectability of chlorate and perchlorate salts with thermal desorption based ionizers (i.e. radioactive, corona discharge and photoionization-based) are desired. This work employs acidic reagents to chemically transform chlorate and perchlorate anions into traces of chloric and perchloric acid. These high vapor pressure acids are easier...

READ MORE

Recommender systems for the Department of Defense and intelligence community

Summary

Recommender systems, which selectively filter information for users, can hasten analysts' responses to complex events such as cyber attacks. Lincoln Laboratory's research on recommender systems may bring the capabilities of these systems to analysts in both the Department of Defense and intelligence community.
READ LESS

Summary

Recommender systems, which selectively filter information for users, can hasten analysts' responses to complex events such as cyber attacks. Lincoln Laboratory's research on recommender systems may bring the capabilities of these systems to analysts in both the Department of Defense and intelligence community.

READ MORE

Recommender systems for the Department of Defense and intelligence community

Summary

Recommender systems, which selectively filter information for users, can hasten analysts' responses to complex events such as cyber attacks. Lincoln Laboratory's research on recommender systems may bring the capabilities of these systems to analysts in both the Department of Defense and intelligence community.
READ LESS

Summary

Recommender systems, which selectively filter information for users, can hasten analysts' responses to complex events such as cyber attacks. Lincoln Laboratory's research on recommender systems may bring the capabilities of these systems to analysts in both the Department of Defense and intelligence community.

READ MORE

Finding malicious cyber discussions in social media

Summary

Today's analysts manually examine social media networks to find discussions concerning planned cyber attacks, attacker techniques and tools, and potential victims. Applying modern machine learning approaches, Lincoln Laboratory has demonstrated the ability to automatically discover such discussions from Stack Exchange, Reddit, and Twitter posts written in English.
READ LESS

Summary

Today's analysts manually examine social media networks to find discussions concerning planned cyber attacks, attacker techniques and tools, and potential victims. Applying modern machine learning approaches, Lincoln Laboratory has demonstrated the ability to automatically discover such discussions from Stack Exchange, Reddit, and Twitter posts written in English.

READ MORE

Threat-based risk assessment for enterprise networks

Published in:
Lincoln Laboratory Journal, Vol. 22, No. 1, 2016, pp. 33-45.

Summary

Protecting enterprise networks requires continuous risk assessment that automatically identifies and prioritizes cyber security risks, enables efficient allocation of cyber security resources, and enhances protection against modern cyber threats. Lincoln Laboratory created a network security model to guide the development of such risk assessments and, for the most important cyber threats, designed practical risk metrics that can be computed automatically and continuously from security-relevant network data.
READ LESS

Summary

Protecting enterprise networks requires continuous risk assessment that automatically identifies and prioritizes cyber security risks, enables efficient allocation of cyber security resources, and enhances protection against modern cyber threats. Lincoln Laboratory created a network security model to guide the development of such risk assessments and, for the most important cyber...

READ MORE

Cloudbreak: answering the challenges of cyber command and control

Published in:
Lincoln Laboratory Journal, Vol. 22, No. 1, 2016, pp. 60-73.

Summary

Lincoln Laboratory's flexible, user-centered framework for the development of command-and-control systems allows the rapid prototyping of new system capabilities. This methodology, Cloudbreak, effectively supports the insertion of new capabilities into existing systems and fosters user acceptance of new tools.
READ LESS

Summary

Lincoln Laboratory's flexible, user-centered framework for the development of command-and-control systems allows the rapid prototyping of new system capabilities. This methodology, Cloudbreak, effectively supports the insertion of new capabilities into existing systems and fosters user acceptance of new tools.

READ MORE