Publications

This paper describes the MIT-LL/AFRL statistical MT system and the improvements that were developed during the IWSLT 2013 evaluation campaign [1]. As part of these efforts, we experimented with a number of extensions to the standard phrase-based model that improve performance on the Russian to English, Chinese to English, Arabic...

An MS-based framework was developed to quantitatively assess API ion-molecule reagent chemistries based on ammonium selectivity versus competing ions, and intrinsic ammonium binding strength and complex survivability for detection. Methyl acetoacetate is an attractive ammonium reagent for vapor-phase API techniques given its high vapor pressure, preferential selectivity, and high critical...

A superstrate-enhanced substrate-loaded array (SESLA) with an integrated feed is presented. The design allows for a practical implementation of the SESLA, a concept previously presented by the authors for realizing extremely wideband (> 10 : 1) low-profile arrays. Specifically, the feed provides unbalanced to balanced transformation allowing the balance-fed SESLA...

This report provides an assessment of the applicability of Systems-Theoretic Process Analysis (STPA) to perform preliminary risk-based modeling of complex NextGen concepts, based on the observed application of STPA to Interval Management-Spacing (IM-S) as a case study. The report also considers the potential use of STPA as a formal tool...

Since the introduction of return-oriented programming, increasingly compiles defenses and subtle attacks that bypass them have been proposed. Unfortunately the lack of a unifying threat model among code reuse security papers makes it difficult to evaluate the effectiveness of defenses, and answer critical questions about the interoperability, composability, and efficacy...

It has long been thought that macroscopic phase coherence breaks down in effectively lower-dimensional superconducting systems even at zero temperature due to enhanced topological quantum phase fluctuations. In quasi-one-dimensional wires, these fluctuations are described in terms of 'quantum phase-slip' (QPS): tunneling of the superconducting order parameter for the wire between...

Hands-on instruction in engineering education is beneficial to the development of a workforce that understands the complexity of building radar systems. Unfortunately, building phased array systems tends to be too costly to allow student access to the hardware necessary for developing these skills. This paper presents a low cost phased...

This paper summarizes the challenges in achieving (and even specifying) the antenna polarization accuracy requirements for the Multifunction Phased Array Radar (MPAR) and the progress that has been made towards meeting these requirements through demonstrations and theoretical investigations.

This paper describes a method to answer the following questions: can several of the elements of a phased array be employed as auxiliary (AUX) elements and how can the phase of each be adjusted so that the (1) cross-polarization (cross-pol) isolation is minimized to 40 dB, (2) the sidelobe levels...

We demonstrate a 149 W Yb:LiYF4 laser with diffraction-limitation beam quality at 995 nm. The laser, Q-switched at 10 kHz pulse repetition frequency, produces linearly polarized 52 ns pulses with a slope efficiency of 73%. The combination of cryogenic cooling and a low (3.5%) quantum defect results in minimal thermo-optic...