Consistency of stochastic context-free grammars from probabilisticestimation based on growth transformations

An important problem related to the probabilistic estimation of stochastic context-free grammars (SCFGs) is guaranteeing the consistency of the estimated model. This problem was considered by Booth-Thompson (1973) and Wetherell (1980) and studied by Maryanski (1974) and Chaudhuri et al. (1983) for unambiguous SCFGs only, when the probability distributions were estimated by the relative frequencies in a training sample. In this work, we extend this result by proving that the property of consistency is guaranteed for all SCFGs without restrictions, when the probability distributions are learned from the classical inside-outside and Viterbi algorithms, both of which are based on growth transformations. Other important probabilistic properties which are related to these results are also proven     

High-temperature polyimide nanofoams for microelectronic applications

Foamed polyimides have been developed in order to obtain thin film dielectric layers with very low dielectric constants for use in microelectronic devices. In these systems the pore sizes are in the nanometer range, thus, the term ‘nanofoam’. The polyimide foams are prepared from block copolymers consisting of thermally stable and thermally labile blocks, the latter being the dispersed phase. Foam formation is effected by thermolysis of the thermally labile block, leaving pores of the size and shape corresponding to the initial copolymer morphology. Nanofoams prepared from a number of polyimides as matrix materials were investigated as well as from a number of thermally labile polymers. The foams were characterized by a variety of experiments including TEM, SAXS, WAXD, DMTA, density measurements, refractive index measurements and dielectric constant measurements. Thin film foams, with high thermal stability and low dielectric constants approaching 2.0, can be prepared using the copolymer/nanofoam approach.     

Self-Synchronous and Self-Referenced Coherent Beam Combination for Large Optical Arrays

A novel and highly accurate electronic technique for phase locking arrays of optical fiber amplifiers is demonstrated. This is the only electronic phase locking technique that does not require a reference beam. The measured phase error for this system is lambda /20. A model for calculating the signal-shot noise-limited phase errors and the phase-modulation-induced phase errors is developed. For the first time, nine fiber amplifiers are coherently combined. The total power in the phase locked array is 100 W.     

Allelotype analysis of uterine leiomyoma: localization of a potential tumor suppressor gene to a 4-cM region of chromosome 7q

The degree and nature of patient involvement in consultations with health professionals influences problem and needs recognition and management, and public accountability. This paper suggests a framework for understanding the scope for patient involvement in such consultations. Patients are defined as co-producers of formal health services, whose potential for involvement in consultations depends on their personal rights, responsibilities and preferences. Patients' rights in consultations are poorly defined and, in the National Health Service (NHS), not legally enforceable. The responsibilities of patients are also undefined. I suggest that these are not to deny, of their own volition, the rights of others, which in consultations necessitate mutuality of involvement through information-exchange and shared decision-making. Preferences should be met insofar as they do not militate against responsibilities and rights.     

Functional adrenal cortical tumors in childhood: a study of ploidy, p53-protein and nucleolar organizer regions (AgNORs) as prognostic markers

The Washington State Patrol Crash Database and computerized hospitalization records for 1989-1993 were used to determine total hospital charges billed for motor vehicle collision injuries to drivers whose crash reports contained any indication of alcohol use. In this population-based study, total hospital charges were summed, and mean charges and lengths of stay were computed within alcohol use and insurance coverage status categories in an attempt to evaluate the hospital charges billed to public funding and private insurance. Of the total hospital charges for drivers with injuries from motor vehicle collisions for which a police-reported indicator of alcohol use status was available, 43% (U.S.$64.8 million) were for drivers who reportedly had been drinking. At the time of discharge, Medicaid was identified as the payor for 47% of these hospitalizations. The mean hospital charge billed per collision was greater for drinking (U.S.$18,258) than nondrinking drivers (U.S.$14,181). Drinking drivers also had longer hospital stays, even after adjustment for patient age, gender and injury severity. During this time in Washington state, the average annual amount billed at discharge for initial inpatient care of injuries to drivers who reportedly had been drinking at the time of the motor vehicle collision was U.S.$13 million. This includes only the amount assessed by the hospital at the time of discharge for treatment of the initial injury and does not include other related medical charges for rehabilitation or outpatient care, or for doctors' or laboratory fees. As increasing pressures of managed and capitated care lead to a shift of financial risk from the federal government and insurers to states and providers, the financial burden of specific, potentially preventable conditions such as this will receive greater attention.     

Direct function calls in lisp

This paper compares implementation strategies for function calls in compiled Lisp. We discuss various ways of allowing compiled call instructions to branch immediately to a callee's code (direct calls), rather than to refer to a symbol that points to the function's definition (indirect calls). We examine the performance of direct and indirect function calls on the VAX and MC68020, and on a RISC architecture—the SPUR multiprocessor. For the SPUR architecture, single indirection slows applications by 3–4%, and double indirection slows applications by 6–8%. The performance benefits of direct function calls are considerably smaller for the VAX and MC68020 architectures. We discuss also the costs and complexities involved in implementing direct function calls.     

Transporting Deformations of Face Emotions in the Shape Spaces: A Comparison of Different Approaches

Studying the changes of shape is a common concern in many scientific fields. We address here two problems: (1) quantifying the deformation between two given shapes and (2) transporting this deformation to morph a third shape. These operations can be done with or without point correspondence, depending on the availability of a surface matching algorithm, and on the type of mathematical procedure adopted. In computer vision, the re-targeting of emotions mapped on faces is a common application. We contrast here four different methods used for transporting the deformation toward a target once it was estimated upon the matching of two shapes. These methods come from very different fields such as computational anatomy, computer vision and biology. We used the large diffeomorphic deformation metric mapping and thin plate spline, in order to estimate deformations in a deformational trajectory of a human face experiencing different emotions. Then we use naive transport (NT), linear shift (LS), direct transport (DT) and fanning scheme (FS) to transport the estimated deformations toward four alien faces constituted by 240 homologous points and identifying a triangulation structure of 416 triangles. We used both local and global criteria for evaluating the performance of the 4 methods, e.g., the maintenance of the original deformation. We found DT, LS and FS very effective in recovering the original deformation while NT fails under several aspects in transporting the shape change. As the best method may differ depending on the application, we recommend carefully testing different methods in order to choose the best one for any specific application.

     

Real-time evaluation and visualization of learner performance in a mixed-reality environment for clinical breast examination

We investigate the efficacy of incorporating real-time feedback of user performance within mixed-reality environments (MREs) for training real-world tasks with tightly coupled cognitive and psychomotor components. This paper presents an approach to providing real-time evaluation and visual feedback of learner performance in an MRE for training clinical breast examination (CBE). In a user study of experienced and novice CBE practitioners (n = 69), novices receiving real-time feedback performed equivalently or better than more experienced practitioners in the completeness and correctness of the exam. A second user study (n = 8) followed novices through repeated practice of CBE in the MRE. Results indicate that skills improvement in the MRE transfers to the real-world task of CBE of human patients. This initial case study demonstrates the efficacy of MREs incorporating real-time feedback for training real-world cognitive-psychomotor tasks.