Publications
Validating and restoring defense in depth using attack graphs
Summary
Summary
Defense in depth is a common strategy that uses layers of firewalls to protect Supervisory Control and Data Acquisition (SCADA) subnets and other critical resources on enterprise networks. A tool named NetSPA is presented that analyzes firewall rules and vulnerabilities to construct attack graphs. These show how inside and outside...
Securing communication of dynamic groups in dynamic network-centric environments
Summary
Summary
We developed a new approach and designed a practical solution for securing communication of dynamic groups in dynamic network-centric environments, such as airborne and terrestrial on-the-move networks. The solution is called Public Key Group Encryption (PKGE). In this paper, we define the problem of group encryption, motivate the need for...
Analysis of nonmodal phonation using minimum entropy deconvolution
Summary
Summary
Nonmodal phonation occurs when glottal pulses exhibit nonuniform pulse-to-pulse characteristics such as irregular spacings, amplitudes, and/or shapes. The analysis of regions of such nonmodality has application to automatic speech, speaker, language, and dialect recognition. In this paper, we examine the usefulness of a technique called minimum-entropy deconvolution, or MED, for...
Reducing speech coding distortion for speaker identification
Summary
Summary
In this paper, we investigate the degradation of speaker identification performance due to speech coding algorithms used in digital telephone networks, cellular telephony, and voice over IP. By analyzing the difference between front-end feature vectors derived from coded and uncoded speech in terms of spectral distortion, we are able to...
Pitch-scale modification using the modulated aspiration noise source
Summary
Summary
Spectral harmonic/noise component analysis of spoken vowels shows evidence of noise modulations with peaks in the estimated noise source component synchronous with both the open phase of the periodic source and with time instants of glottal closure. Inspired by this observation of natural modulations and of fullband energy in the...
Missing feature theory with soft spectral subtraction for speaker verification
Summary
Summary
This paper considers the problem of training/testing mismatch in the context of speaker verification and, in particular, explores the application of missing feature theory in the case of additive white Gaussian noise corruption in testing. Missing feature theory allows for corrupted features to be removed from scoring, the initial step...
An overview of automatic speaker diarization systems
Summary
Summary
Audio diarization is the process of annotating an input audio channel with information that attributes (possibly overlapping) temporal regions of signal energy to their specific sources. These sources can include particular speakers, music, background noise sources, and other signal source/channel characteristics. Diarization can be used for helping speech recognition, facilitating...
Toward an interagency language roundtable based assessment of speech-to-speech translation capabilitites
Summary
Summary
We present observations from three exercises designed to map the effective listening and speaking skills of an operator of a speech-to-speech translation system (S2S) to the Interagency Language Roundtable (ILR) scale. Such a mapping is nontrivial, but will be useful for government and military decision makers in managing expectations of...
Experience using active and passive mapping for network situational awareness
Summary
Summary
Passive network mapping has often been proposed as an approach to maintain up-to-date information on networks between active scans. This paper presents a comparison of active and passive mapping on an operational network. On this network, active and passive tools found largely disjoint sets of services and the passive system...
Advanced language recognition using cepstra and phonotactics: MITLL system performance on the NIST 2005 Language Recognition Evaluation
Summary
Summary
This paper presents a description of the MIT Lincoln Laboratory submissions to the 2005 NIST Language Recognition Evaluation (LRE05). As was true in 2003, the 2005 submissions were combinations of core cepstral and phonotactic recognizers whose outputs were fused to generate final scores. For the 2005 evaluation, Lincoln Laboratory had...