A Content-Addressable Network for Similarity Search in Metric Spaces

Because of the ongoing digital data explosion, more advanced search paradigms than the traditional exact match are needed for contentbased retrieval in huge and ever growing collections of data produced in application areas such as multimedia, molecular biology, marketing, computer-aided design and purchasing assistance. As the variety of data types is fast going towards creating a database utilized by people, the computer systems must be able to model human fundamental reasoning paradigms, which are naturally based on similarity. The ability to perceive similarities is crucial for recognition, classification, and learning, and it plays an important role in scientific discovery and creativity. Recently, the mathematical notion of metric space has become a useful abstraction of similarity and many similarity search indexes have been developed. In this thesis, we accept the metric space similarity paradigm and concentrate on the scalability issues. By exploiting computer networks and applying the Peer-to-Peer communication paradigms, we build a structured network of computers able to process similarity queries in parallel. Since no centralized entities are used, such architectures are fully scalable. Specifically, we propose a Peer-to-Peer system for similarity search in metric spaces called Metric Content-Addressable Network (MCAN) which is an extension of the well known Content-Addressable Network (CAN) used for hash lookup. A prototype implementation of MCAN was tested on real-life datasets of image features, protein symbols, and text — observed results are reported. We also compared the performance of MCAN with three other, recently proposed, distributed data structures for similarity search in metric spaces

An Analytical Study for Subsonic Oblique Wing Transport Concept

The oblique wing concept has been investigated for subsonic transport application for a cruise Mach number of 0.95. Three different mission applications were considered and the concept analyzed against the selected mission requirements. Configuration studies determined the best area of applicability to be a commercial passenger transport mission. The critical parameter for the oblique wing concept was found to be aspect ratio which was limited to a value of 6.0 due to aeroelastic divergence. Comparison of the concept final configuration was made with fixed winged configurations designed to cruise at Mach 0.85 and 0.95. The crossover Mach number for the oblique wing concept was found to be Mach 0.91 for takeoff gross weight and direct operating cost. Benefits include reduced takeoff distance, installed thrust and mission block fuel and improved community noise characteristics. The variable geometry feature enables the final configuration to increase range by 10% at Mach 0.712 and to increase endurance by as much as 44%

Development of compressor end seals stator interstage seals, and stator pivot seals in air breathing propulsion systems Semiannual report no. 1, 29 Jun. - 31 Dec. 1965

Seal concepts evaluation for compressor end seals, stator interchange seals, and stator pivot seals in air breathing propulsion syste

Determination of wind tunnel constraint effects by a unified pressure signature method. Part 1: Applications to winged configurations

A new, fast, non-iterative version of the "Wall Pressure Signature Method" is described and used to determine blockage and angle-of-attack wind tunnel corrections for highly-powered jet-flap models. The correction method is complemented by the application of tangential blowing at the tunnel floor to suppress flow breakdown there, using feedback from measured floor pressures. This tangential blowing technique was substantiated by subsequent flow investigations using an LV. The basic tests on an unswept, knee-blown, jet flapped wing were supplemented to include the effects of slat-removal, sweep and the addition of unflapped tips. C sub mu values were varied from 0 to 10 free-air C sub l's in excess of 18 were measured in some cases. Application of the new methods yielded corrected data which agreed with corresponding large tunnel "free air" resuls to within the limits of experimental accuracy in almost all cases. A program listing is provided, with sample cases

Conceptual design study of a Harrier V/STOL research aircraft

MCAIR recently completed a conceptual design study to define modification approaches to, and derive planning prices for the conversion of a two place Harrier to a V/STOL control, display and guidance research aircraft. Control concepts such as rate damping, attitude stabilization, velocity command, and cockpit controllers are to be demonstrated. Display formats will also be investigated, and landing, navigation and guidance systems flight tested. The rear cockpit is modified such that it can be quickly adapted to faithfully simulate the controls, displays and handling qualities of a Type A or Type B V/STOL. The safety pilot always has take command capability. The modifications studied fall into two categories: basic modifications and optional modifications. Technical descriptions of the basic modifications and of the optional modifications are presented. The modification plan and schedule as well as the test plan and schedule are presented. The failure mode and effects analysis, aircraft performance, aircraft weight, and aircraft support are discussed

Advanced flight control system study

The architecture, requirements, and system elements of an ultrareliable, advanced flight control system are described. The basic criteria are functional reliability of 10 to the minus 10 power/hour of flight and only 6 month scheduled maintenance. A distributed system architecture is described, including a multiplexed communication system, reliable bus controller, the use of skewed sensor arrays, and actuator interfaces. Test bed and flight evaluation program are proposed

Space tug/shuttle interface compatibility study. Volume 2: Tug/payload/orbiter interface analyses

For abstract, see N75-27050

F-111 Systems Engineering Case Study

The systems engineering lessons from the F-111 program will facilitate learning by emphasizing practical applications and resulting outcomes to the current processes and tools used on today s programs. The student will understand the long-term consequences of systems engineering as implemented on the F-111 and its effect on cost, schedule, and operational effectiveness. The reader can then postulate outcomes of alternate decisions at the program/system level

AN EXAMINATION OF THE EFFECTIVENESS OF POIRIER\u27S TEAM LEARNING IN REDUCING THE NUMBER OF SOCIALLY ISOLATED ELEMENTARY SCHOOL CHILDREN AND THE INTENSITY OF SOCIAL ISOLATION OF FRINGE ISOLATE CHILDREN IN THE ELEMENTARY SCHOOL CLASSROOM

PROBLEM: Because of the detrimental effects of social isolation on children\u27s achievement, peer relations and self-image, there is a need for an effective classroom organizational program which will reduce the number of isolates and fringe isolates among elemertary school children. PURPOSE: Since Poirier\u27s team learning exposes the isolate to a high incidence of social interaction, it was the objective of this study to investigate the effectiveness of Poirier\u27s team learning in improving the sociometric standing of children identified as social isolates and fringe social isolates in the elementary school. PROCEDURES: Twenty -two randomly selected classes were selected from six San Francisco Bay Area school districts. The teachers of the eleven experimental classes were given inservice training in the principles of Poirier\u27s team learning. For approximately five months, the children in the experimental classes were organized into learning teams of five to six students. Each team worked together on assignments. The children in each team were instructed to help one another whenever possible. Each group received team points for their collective efforts. Rewards were often given. Cooperative competition between teams was encouraged. All children were given Georgia Sachs Adams\u27 sociometric surveys to determine their sociometric standing. The chisquare was used to test the effect of Poirier\u27s team learning on the rejection of social isolates and highly rejected fringe social isolates. The analvsis of variance was used to test the effec t of Poirier\u27s team learning on the intensity of rejection of the fringe social isolate by his peers. FINDINGS: No significant difference was found to exist between the number of isolates in the experimental group and those in the control group . No significant difference was found to exist between the number of isolates and highly rejected isolates combined in the experimental group and those in the control group. A significant difference was found to exist between the mean of the scores of the fringe isolates of the experimental group and that of the control group. However, this difference was the direct antithesis of that anticipated by the researcher and indicated that classes in the study using Poirier\u27s team learning had significantly more isolates in them than did classes not usinq Poirier\u27s team learninq. CONCLUSIONS: The finding reject the hypothesis the Poirier classes would have significantly fewer social isolates in them. On the contrary , although not statistically significant , the team learning classes had more isolates in them than did the control classes . The findings also rejected the hypothesis that Poirier classes would have significantly fewer isolates and highly rejected social fringe isolates combined in them than classes not using Poirier\u27s team learning. Again, although not significant , the classes using Poirier\u27s team learning had more isolates and highly rejected fringe isolates in them than did the control group classes. The findings rejected the hypothesis that Poirier classes wou ld have fringe isolates with significantly higher social acceptance scores than those children in classes not using Poirier\u27s team learning. In fact, the converse was true. Fringe isolates in Poirier classes had si gnificantly lower social acceptance scores than those in the control classes. This was the direct antithesis of the assumptions of this study. RECOMMENDATIONS FOR FURTHER RESEARCH: Four further investigations are recommended: (1) Experiment to ascertain the effect of competition on social isolates. (2) Experimen t to ascertain what changes, if any, occur in social acceptance within a learning team from the time it is organized to its deactivation. (3) Experiment to ascertain what effect pl aci ng less socially accepted children with those who have nominated them on a sociometric survey will have on social status. (4) Experiment to ascertain what effect to social status model-reinforcement group counseling would have