Improved Arabic-to-English statistical machine translation by reordering post-verbal subjects for word alignment

We study challenges raised by the order of Arabic verbs and their subjects in statistical machine translation (SMT). We show that the boundaries of post-verbal subjects (VS) are hard to detect accurately, even with a state-of-the-art Arabic dependency parser. In addition, VS constructions have highly ambiguous reordering patterns when translated to English, and these patterns are very different for matrix (main clause) VS and non-matrix (subordinate clause) VS. Based on this analysis, we propose a novel method for leveraging VS information in SMT: we reorder VS constructions into pre-verbal (SV) order for word alignment. Unlike previous approaches to source-side reordering, phrase extraction and decoding are performed using the original Arabic word order. This strategy significantly improves BLEU and TER scores, even on a strong large-scale baseline. Limiting reordering to matrix VS yields further improvements.     

Laser-Based Printing: From Liquids to Microstructures

Assembly of materials into microstructures under laser guidance is attracting wide attention. The ability to pattern various materials and form 2D and 3D structures with micron/sub-micron resolution and less energy and material waste compared with standard top-down methods make laser-based printing promising for many applications, for example medical devices, sensors, and microelectronics. Assembly from liquids provides a smaller feature size than powders and has advantages over other states of matter in terms of relatively simple setup, easy handling, and recycling. However, the simplicity of the setup conceals a variety of underlying mechanisms, which cannot be identified simply according to the starting or resulting materials. This progress report surveys the various mechanisms according to the source of the material—preformed or locally synthesized. Within each category, methods are defined according to the driving force of material deposition. The advantages and limitations of each method are critically discussed, and the methods are compared, shedding light on future directions and developments required to advance this field.     

Microstructure of GaN grown by lateral confined epitaxy 2. GaN on patterned sapphire

Transmission electron microscopy (TEM), atomic force microscopy (AFM), and photoluminescence (PL) spectroscopy were used in order to study the microstructure and optical properties of GaN films grown by metal-organic chemical vapor deposition (MOCVD) on c-plane sapphire by lateral confined epitaxy (LCE). In this method, the substrate is etched prior to growth to form uniform mesas separated by trenches for laterally restricting growth area. As previously observed for LCE GaN on Si(111), the density of threading dislocations was significantly reduced in the areas close to the edge of mesas due to the lateral propagation of the dislocations. Hence, the overall material quality improves with decreasing mesa size, which is consistent with the observed increase in photoluminescence band edge peak intensity. Electron diffraction indicated ∼1° rotation about the [ ] axis between the mesa and trench material, which was also observed in the image contrast of these two regions with g= . Additionally, LCE samples prepared in [ ] and [ ] cross sections were used for comparing the growth rates in these two perpendicular directions. As theoretically expected, growth in the [ ] direction appears to proceed considerably faster than that in the [% MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9qqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaaGymaiaaig% daceaIYaGbaebacaaIWaaaaa!38D1!\[11\bar 20\]] direction.     

Immittance-type tabular stability test for 2-D LSI systems based on a zero location test for 1-D complex polynomials

A new algebraic test is developed to determine whether or not a two-variable (2-D) characteristic polynomial of a recursive linear shift invariant (LSI, discrete-time) system is stable (i.e., it does not vanish in the closed exterior of the unit bi-circle). The method is based on the original form of a unit-circle zero location test for one variable (1-D) polynomials with complex coefficients proposed by the author. The test requires the construction of a table, in the form of a sequence of centrosymmetric matrices or 2-D polynomials, that is obtained using a certain three-term recursion, and examination of the zero location with respect to the unit circle of a few associated 1-D polynomials. The minimal set necessary and sufficient conditions for 2-D stability involves one 1-D polynomial whose zeros must reside inside the unit circle (which may be examined before the table is constructed), and one symmetric 1-D polynomial (which becomes available after completing the table) that is required not to have zeros on the unit circle. A larger set of intermediate necessary conditions for stability (which may be examined during the table's construction) are also given. The test compares favorably with Jury's recently improved 2-D stability test in terms of complexity and munerical stability.     

Adaptive versus Non-Adaptive Security of Multi-Party Protocols

Security analysis of multi-party cryptographic protocols distinguishes between two types of adversarial settings: In the non-adaptive setting the set of corrupted parties is chosen in advance, before the interaction begins. In the adaptive setting the adversary chooses who to corrupt during the course of the computation. We study the relations between adaptive security (i.e., security in the adaptive setting) and nonadaptive security, according to two definitions and in several models of computation.     

Optical compressive change and motion detection

Localization information of moving and changing objects, as commonly extracted from video sequences, is typically very sparse with respect to the full data frames, thus fulfilling one of the basic conditions of compressive sensing theory. Motivated by this observation, we developed an optical compressive change and motion-sensing technique that detects the location of moving objects by using a significantly fewer samples than conventionally taken. We present examples of motion detection and motion tracking with over two orders of magnitude fewer samples than required with conventional systems.     

Modeling the Aeration Efficiency of a Passively Aerated Vertical-Flow Biological Filter

A model aimed at calculating the aeration efficiency of a passively aerated biological vertical bed unit is presented. The model allows the calculation of the mass of air that would flow via convection into the vertical bed, therefore enabling the prediction of the maximal capacity of the bed as an aerobic biological reactor. Aeration efficiency, defined as the volume of air that would enter the bottom of the bed as a function of the volume of water that is drained from it, is predicted in the model as a function of the mean particle size of the gravel media, and the diameter and number of the aeration tubes installed. The model was calibrated in the laboratory and verified using results from a pilot scale vertical bed treating secondary municipal wastewater effluents. The principal model equation is: EPAVB = NPDp4/(NPDp4+0.285pDr22), where EPAFB=efficiency of the passive air pump (—); NP=number of aeration pipes (—); Dp=aeration pipes’ diameter (m); p=medium porosity (—); and Dr=vertical bed diameter (m).     

Deadlock-free connection-based adaptive routing with dynamic virtual circuits

Virtual circuits (VCs) can reduce routing overheads with irregular topologies and provide support for a mix of quality of service (QoS) requirements. Information about network loads and traffic patterns may be used during circuit establishment to utilize network resources more efficiently than is practical with packet routing. Most VC schemes are static—each established VC remains unchanged until the connection is no longer needed. In contrast, we propose the dynamic virtual circuit (DVC) mechanism, which enables existing circuits to be quickly torn down in order to free up resources needed for other circuits or to re-establish circuits along routes that are better suited for current network conditions. We propose a deadlock avoidance technique, based on unconstrained routing of DVCs combined with a deadlock-free virtual network. We present a correctness proof for the scheme, describe key aspects of its implementation, and present performance evaluation results that explore its potential benefits.     

Coulomb oscillations and Hall effect in quasi-2D graphite quantum dots

We perform low-temperature electrical transport measurements on gated, quasi-2D graphite quantum dots. In devices with low contact resistances, we use longitudinal and Hall resistances to extract carrier densities of 9.2-13 x 10(12) cm(-2) and mobilities of 200-1900 cm(2)/V.s. In devices with high resistance contacts, we observe Coulomb blockade phenomena and infer the charging energies and capacitive couplings. These experiments demonstrate that electrons in mesoscopic graphite pieces are delocalized over nearly the whole graphite piece down to low temperatures.