Polarization Aberrations

The analysis of the polarization characteristics displayed by optical systems can be divided into two categories: geometrical and physical. Geometrical analysis calculates the change in polarization of a wavefront between pupils in an optical instrument. Physical analysis propagates the polarized fields wherever the geometrical analysis is not valid, i.e., near the edges of stops, near images, in anisotropic media, etc. Polarization aberration theory provides a starting point for geometrical design and facilitates subsequent optimization. The polarization aberrations described arise from differences in the transmitted (or reflected) amplitudes and phases at interfaces. The polarization aberration matrix (PAM) is calculated for isotropic rotationally symmetric systems through fourth order and includes the interface phase, amplitude, linear diattenuation, and linear retardance aberrations. The exponential form of Jones matrices used are discussed. The PAM in Jones matrix is introduced. The exact calculation of polarization aberrations through polarization ray tracing is described. The report is divided into three sections: I. Rotationally Symmetric Optical Systems; II. Tilted and Decentered Optical Systems; and Polarization Analysis of LIDARs

An analysis of the effectiveness and contribution to the needs of its graduates, in the worthy use of leisure time, of the boys physical education program in the Dedham, Massachusetts, High School.

Thesis (Ed.M.)--Boston Universit

Late Pleistocene to Holocene sedimentology, palaeoceanography and micropalaeontology of the Uruguayan continental slope

This study utilises an extensive set of sediment cores collected from a largely unstudied contourite and turbidite depositional system located on the Uruguay continental margin to identify a method of distinguishing deposits in the deep sea that are sourced from either gravity or bottom current sedimentary processes. The cores acquired by BG Group in 2014 targeted areas of the ocean floor that encompass both Late Pleistocene to Holocene age) large sediment drifts and large downslope canyons, where turbidite and contourite deposition occurs simultaneously. Core, sediment and micropalaeontological analysis has been used to answer three basic questions 1) Do the sediments collected from different geomorphic settings owe their origin to along-slope (contourite) or gravitational (turbidite) transport? 2) Do the drift sediments contain a record of palaeoceanographic change? and 3) Can micropalaeontologcial analysis resolve long-standing problems with differentiating along- and down-slope processes in the geological record.The presented study provides new data resolving these three questions for the upper, middle and lower Uruguayan slope. The new data comprises;1. A detailed examination of the sedimentary facies of the (LatePleistocene to Holocene) Uruguay slope, while ground-truthing interpretations from seismic and bathymetric data collected from the same area that is broadly contemporaneous2. A reconstruction of watermass migration using stable isotope, elemental ratios and foraminiferal indices accumulated on the Uruguay slope since the Last Glacial Maximum3. A classification of foraminiferal assemblages for that are likely to be indicative of specific sedimentary facies in turbidite and contourite deposits in order to distinguish these facies from one another in a sedimentary environment where both contourite and turbidite deposition has occurred.This data elucidates some important new insights into the studied system and more broadly contourite and turbidite deposits globally:1. A new model of mixed sedimentary system evolution on the Uruguay slope since the Last Glacial Maximum and how it is intrinsically linked to bottom-current/seafloor interactions2. A new model for the flux of Antarctic sourced watermasses into the Atlantic basin across deglaciation3. A new criterion for distinguishing contourites and from turbidite facies by using benthic foraminiferal ecological disturbance-succession patterns

A communications model for an ISAS to NASA span link

The authors propose that an initial computer-to-computer communication link use the public packet switched networks (PPSN) Venus-P in Japan and TELENET in the U.S. When the traffic warrants it, this link would then be upgraded to a dedicated leased line that directly connects into the Space Physics Analysis Network (SPAN). The proposed system of hardware and software will easily support migration to such a dedicated link. It therefore provides a cost effective approach to the network problem. Once a dedicated line becomes operation it is suggested that the public networks link and continue to coexist, providing a backup capability

A Hierarchical Database Model for a Logic Programming Language

This paper presents an extended Clausal Database Model for a logic programming language. Instead of being restricted to one global database, as is the case with Prolog, we allow segmentation of the database into database units which are linked together into a semi-lattice. Each database unit defines a database view which includes clauses which have been asserted into that unit as well as clauses inherited from its ancestors higher in the lattice structure. This model supports arbitrary retraction. Retracting a clause in a database unit effectively blocks its inheritance for that unit and all of its descendants. Motivations for using this model are given. We also discuss the implementation of a Prolog meta-interpreter that uses this model. (hereafter referred to as (Phd) or Prolog Hierarchical Database) This meta-interpreter is in the spirit of Prolog and therefore has a version of assert, retract and cut