Building language resources for a Multi-Engine English-Filipino machine translation system

In this paper, we present the building of various language resources for a multi-engine bi-directional English-Filipino Machine Translation (MT) system. Since linguistics information on Philippine languages are available, but as of yet, the focus has been on theoretical linguistics and little is done on the computational aspects of these languages, attempts are reported here on the manual construction of these language resources such as the grammar, lexicon, morphological information, and the corpora which were literally built from almost non-existent digital forms. Due to the inherent difficulties of manual construction, we also discuss our experiments on various technologies for automatic extraction of these resources to handle the intricacies of the Filipino language, designed with the intention of using them for the MT system. To implement the different MT engines and to ensure the improvement of translation quality, other language tools (such as the morphological analyzer and generator, and the part of speech tagger) were developed.     

Optical tests of nanoengineered liquid mirrors

We describe a new technology for the fabrication of inexpensive high-quality mirrors. We begin by chemically producing a large number of metallic nanoparticles coated with organic ligands. The partides are then spread on a liquid substrate where they self-assemble to give optical quality reflective surfaces. Since liquid surface can be modified by a variety of means (e.g., rotation, electromagnetic fields), this opens the possibility of making a new class of versatile and inexpensive optical elements that can have complex shapes and that can be modified within short time scales. Interferommetric measurements show optical quality surfaces. We have obtained reflectivity curves that show 80% peak reflectivities. We are confident that we can improve the reflectivity curves because theoretical models predict higher values. We expect nanoengineered liquid mirrors to be useful for scientific and engineering applications. The technology is interesting for large optics, such as large rotating parabolic mirrors, because of its low cost. Furthermore, because the surfaces of of ferrofluids can be shaped with magnetic fields, one can generate complex, time-varying surfaces that are difficult to make with conventional techniques.     

Communication Through Television UNESCO Adult Education Experiments in France, Japan and India

The UNESCO experiments on communication through television in the field of adult education conducted in France, Japan and India during the current and the previous decades demonstrated for the first time the potential of television for thr promotion of culture and education among the general masses. They also indicated that the tele-clubs, organized for group viewing in both urban and rural communities, could be an effective and adequate means for the purpose of communicating messages of social education. The results obtained from the special series of telecasts underscored the fact that the appeal of television was not restricted within national boundaries. The indirect co-operation of France, Japan and India-countries with different cultural backgrounds-toward the growth of a common institution like the tele-club was not merely a significant step in the effort to bring into reality an international exchange of ideas and experiments in the field of educational television; it also reinforced the concept of international communication through a global television system.     

Deposition of ultrafine aerosol particles on wire screens by simultaneous diffusion and image force

This paper presents the results of an experimental investigation on the deposition of multiply charged particles on wire screens by the combined mechanisms of diffusion and image force. Experiments were performed with particles having diameters between 25 and 65 nm (transition regime), carrying 0, +1, +2 or +3 elementary charges, and using three different flow rates, two types of wire screen, and two types of test aerosol. The single fiber efficiencies for the mechanisms of image force, η_IM, and diffusion, η_D, are of the same order of magnitude and, furthermore, they are both much smaller than one. Under these conditions, the total capture efficiency can be approximated as the sum of the efficiencies by diffusion and image force deposition. Theoretically, η_IM is proportional to the square root of a dimensionless number, K_IM, which includes all the relevant parameters cited above (i.e., particle size and charge, aerosol flow rate and screen geometry). The available correlations for η_IM, obtained from experiments with particles carrying a large number of elementary charges (K_IM>10^-5), predict that image force should not have any effect in the case of the small particles with very few number of charges that we have tested in our experiments (in our experimentation, K_IM ranged between 10^-7 and 10^-5). Our results, the only ones available to date for this particle size range, show that there is indeed a clear, measurable effect. Although our experimental results are best fitted by the correlation , it is shown that the expression , which is in agreement with the theoretical 1/2 exponent for K_IM, also reproduces reasonably well the measured values.     

MoOx/Ag/MoOx multilayers as hole transport transparent conductive electrodes for n-type crystalline silicon solar cells

Substitution of highly doped layers with conventional transparent conductive electrodes as carrier collecting and selective contacts in conventional crystalline silicon (c-Si) solar cell configurations is crucial in increasing affordability of solar cells by lowering material costs. In this study, oxide/metal/oxide (OMO) multilayers featuring molybdenum oxide (MoO_x) and silver (Ag) thin films are developed by thermal evaporation technique, as dopant-free hole transport transparent conductive electrodes (HTTCEs) for n-type c-Si solar cells. Semidopant-free asymmetric heterocontact (semi-DASH) solar cells on n-type c-Si utilizing OMO multilayers are fabricated. The effect of outer MoO_x layer thickness and Ag deposition rate on the photovoltaic characteristics of the fabricated semi-DASH solar cells are investigated. A comparison of front side pyramid textured and flat surface solar cells is performed to optimize the optical and electrical properties. Highest efficiency of 9.3% ± 0.2% is achieved in a pyramid textured semi-DASH c-Si solar cell with 15/10/30 nm of HTTCE structure.     

A framework for performance characterization of intermediate-levelgrouping modules

We present five performance measures to evaluate grouping modules in the context of constrained search and indexing based object recognition. Using these measures, we demonstrate a sound experimental framework, based on statistical ANOVA tests, to compare and contrast three edge based organization modules, namely, those of Etemadi et al. (1991), Jacobs (1996), and Sarkar-Boyer (1993) in the domain of aerial objects using 50 images. With adapted parameters, the Jacobs module performs overall the best for constraint based recognition. For fixed parameters, the Sarkar-Boyer module is the best in terms of recognition accuracy and indexing speedup. Etemadi et al.'s module performs equally well with fixed and adapted parameters while the Jacobs module is most sensitive to fixed and adapted parameter choices. The overall performance ranking of the modules is Jacobs, Sarkar-Boyer, and Etemadi et al     

Lidar measurements taken with a large-aperture liquid mirror. 1. Rayleigh-scatter system

A lidar system has been built to measure atmospheric-density fluctuations and the temperature in the upper stratosphere, the mesosphere, and the lower thermosphere, measurements that are important for an understanding of climate and weather phenomena. This lidar system, the Purple Crow Lidar, uses two transmitter beams to obtain atmospheric returns resulting from Rayleigh scattering and sodium-resonance fluorescence. The Rayleigh-scatter transmitter is a Nd:YAG laser that generates 600 mJ/pulse at the second-harmonic frequency, with a 20-Hz pulse-repetition rate. The sodium-resonance-fluorescence transmitter is a Nd:YAG-pumped ring dye laser with a sufficiently narrow bandwidth to measure the line shape of the sodium D(2) line. The receiver is a 2.65-m-diameter liquid-mercury mirror. A container holding the mercury is spun at 10 rpm to produce a parabolic surface of high quality and reflectivity. Test results are presented which demonstrate that the mirror behaves like a conventional glass mirror of the same size. With this mirror, the lidar system's performance is within 10% of theoretical expectations. Furthermore, the liquid mirror has proved itself reliable over a wide range of environmental conditions. The use of such a large mirror presented several engineering challenges involving the passage of light through the system and detector linearity, both of which are critical for accurate retrieval of atmospheric temperatures. These issues and their associated uncertainties are documented in detail. It is shown that the Rayleigh-scatter lidar system can reliably and routinely measure atmospheric-density fluctuations and temperatures at high temporal and spatial resolutions.     

A numerical study of the influence of ion–aerosol mixing on unipolar charging in a laminar flow tube

A theoretical investigation has been carried out to examine the effect of the initial ion–aerosol mixing state on the resulting charged fraction (extrinsic charging efficiency) of ultrafine particles in a circular tube under laminar flow conditions. Particle and ion loss to the walls by diffusion and electrostatic dispersion were taken into account in the calculations. Four different mixing states were considered at the inlet section of the charging tube: (I) uniform mixing of ions and neutral particles; (II) a core of ions surrounded by an envelope of neutral particles; (III) a core of neutral particles surrounded by an envelope of ions; and (IV) the inlet section split up into two circular segments, one containing neutral particles alone, the other only ions. The numerical results show that the extrinsic charging efficiency strongly depends on the initial mixing state, the maximum efficiency being attained for mixing state II, a state which can be easily realized in practice by injecting ions and particles into the charger through two coaxial cylinders. The worst case is that of mixing state III, the reverse of II, in which the neutral particles are injected through the inner cylinder, and the unipolar ions through the annular space between the injection tubes. The main reason underlying the observed behavior is the strong dependency of the ions loss rate to the wall on their initial spatial distribution.     

Ferrofluidic adaptive mirrors

A magnetic liquid mirror based on ferrofluids was demonstrated. Magnetic liquid mirrors represent a major departure from solid mirror technology. They present both advantages and disadvantages with respect to established technologies. Stroke (from a fraction of a wave to several hundreds of micrometers), cost (a few dollars per actuator), and scalability (hundreds of thousands of actuators) are the main advantages. Very large mirrors having diameters of the order of a meter should be feasible. There are a few disadvantages. The most important disadvantage is the time response, which is of the order of a few milliseconds. Although this time response could be further decreased with additional technical developments, it is unlikely to match the speed of solid mirrors. The technology is still in its infancy, and considerable work must still be done. However, the advantages are such that the technology is worth pursuing.     

Telecentric three-dimensional sensor with a liquid mirror for large-object inspection

We describe a device that applies the advantages of the space invariance of telecentric triangulation with the measurement of large objects (1 m(3)). Because the scan motion of the laser beam is decoupled from the physical transport of the sensor head, the fast scanning of large volumes becomes feasible. The device consists of a triangulation laser telemeter head that uses a large liquid primary mirror and an aspheric secondary mirror to realize the telecentric f-theta objective. We propose using liquid-mirror technology to make low-cost large objectives that have low f numbers, a diffraction-limited performance, and low scattering in the visible. This new optical system is useful for 3-D measurement. We discuss the optical configuration of the system and the performance of a laboratory prototype. The prototype has a standoff distance of 1.5 m, a telecentric scan as long as 1 m, a depth of view of 1 m, and a relative depth resolution of 0.5-1 mm.