The effect of errors in the assignment of the transmission functions on the accuracy of the thermal sounding of the atmosphere

In order to test the error of calculation in assumed values of the transmission function for Soviet and American radiometers sounding the atmosphere thermally from orbiting satellites, the assumptions of the transmission calculation is varied with respect to atmospheric CO2 content, transmission frequency, and atmospheric absorption. The error arising from variations of the assumptions from the standard basic model is calculated

On the Coulomb relaxation process of fast particles' distribution in the earth's radiation belts

Coulomb relaxation process of fast particle distribution in earth radiation belt

Automatic Document Summarization Using Knowledge Based System

This dissertation describes a knowledge-based system to create abstractive summaries of documents by generalizing new concepts, detecting main topics and creating new sentences. The proposed system is built on the Cyc development platform that consists of the world’s largest knowledge base and one of the most powerful inference engines. The system is unsupervised and domain independent. Its domain knowledge is provided by the comprehensive ontology of common sense knowledge contained in the Cyc knowledge base. The system described in this dissertation generates coherent and topically related new sentences as a summary for a given document. It uses syntactic structure and semantic features of the given documents to fuse information. It makes use of the knowledge base as a source of domain knowledge. Furthermore, it uses the reasoning engine to generalize novel information. The proposed system consists of three main parts: knowledge acquisition, knowledge discovery, and knowledge representation. Knowledge acquisition derives syntactic structure of each sentence in the document and maps words and their syntactic relationships into Cyc knowledge base. Knowledge discovery abstracts novel concepts, not explicitly mentioned in the document by exploring the ontology of mapped concepts and derives main topics described in the document by clustering the concepts. Knowledge representation creates new English sentences to summarize main concepts and their relationships. The syntactic structure of the newly created sentences is extended beyond simple subject-predicate-object triplets by incorporating adjective and adverb modifiers. This structure allows the system to create sentences that are more complex. The proposed system was implemented and tested. Test results show that the system is capable of creating new sentences that include abstracted concepts not mentioned in the original document and is capable of combining information from different parts of the document text to compose a summary

Tverberg Type Partitions: Sub-Regular and Elliptical Polygons

Tverberg\u27s theorem states that given a set S of T(r,d)=(r-1)(d+1)+1 points in Rd, there exists a partition of S into r subsets whose convex hulls intersect. A feature of Tverberg\u27s theorem is that T(r,d) is tight, so in this senior project we investigate Tverberg-type results when |S|. We found that in R2, given a set S of T(r,2)-2=3r-4 points, and assuming r=r1 r2, there exists a partition of S into r sets such that when grouped into r1 collections of r2 sets, the convex hulls of each collection overlap, and we can find the vertex set of a regular r1-gon with one point from the intersection of each collection. We also show that given a similar construction but with |S|=3r-6, we can find the vertices of an r1-gon in the intersections of convex hulls, with vertices on an ellipse, and other nice regularity properties

A solution to Darwin’s dilemma of 1859 : Exceptional preservation in Salter’s material from the late Ediacaran Longmyndian Supergroup, England

Peer reviewedPostprin