Satellite on-board processing for earth resources data

Results of a survey of earth resources user applications and their data requirements, earth resources multispectral scanner sensor technology, and preprocessing algorithms for correcting the sensor outputs and for data bulk reduction are presented along with a candidate data format. Computational requirements required to implement the data analysis algorithms are included along with a review of computer architectures and organizations. Computer architectures capable of handling the algorithm computational requirements are suggested and the environmental effects of an on-board processor discussed. By relating performance parameters to the system requirements of each of the user requirements the feasibility of on-board processing is determined for each user. A tradeoff analysis is performed to determine the sensitivity of results to each of the system parameters. Significant results and conclusions are discussed, and recommendations are presented

Voyager spacecraft phase B, task D. Volume 2 - System description. Book 5 - Final report

Voyager spacecraft design standards, and operational support and mission-dependent equipment requirement

A Lightweight N-Cover Algorithm For Diagnostic Fail Data Minimization

The increasing design complexity of modern ICs has made it extremely difficult and expensive to test them comprehensively. As the transistor count and density of circuits increase, a large volume of fail data is collected by the tester for a single failing IC. The diagnosis procedure analyzes this fail data to give valuable information about the possible defects that may have caused the circuit to fail. However, without any feedback from the diagnosis procedure, the tester may often collect fail data which is potentially not useful for identifying the defects in the failing circuit. This not only consumes tester memory but also increases tester data logging time and diagnosis run time. In this work, we present an algorithm to minimize the amount of fail data used for high quality diagnosis of the failing ICs. The developed algorithm analyzes outputs at which the tests failed and determines which failing tests can be eliminated from the fail data without compromising diagnosis accuracy. The proposed algorithm is used as a preprocessing step between the tester data logs and the diagnosis procedure. The performance of the algorithm was evaluated using fail data from industry manufactured ICs. Experiments demonstrate that on average, 43% of fail data was eliminated by our algorithm while maintaining an average diagnosis accuracy of 93%. With this reduction in fail data, the diagnosis speed was also increased by 46%

Digital Image Access & Retrieval

The 33th Annual Clinic on Library Applications of Data Processing, held at the University of Illinois at Urbana-Champaign in March of 1996, addressed the theme of "Digital Image Access & Retrieval." The papers from this conference cover a wide range of topics concerning digital imaging technology for visual resource collections. Papers covered three general areas: (1) systems, planning, and implementation; (2) automatic and semi-automatic indexing; and (3) preservation with the bulk of the conference focusing on indexing and retrieval.published or submitted for publicatio

Investigating the suitability of laser sintered elastomers for running footwear applications

The research contained within this thesis formed part of an Engineering and Physical Sciences Research Council (EPSRC) funded project based at Loughborough University, which aimed to investigate the use of additive manufacturing (AM), and in particular sintering technologies, for the production of running footwear sole units. Laser sintering (LS) is an AM process which produces parts directly from a computer aided design (CAD) file by selectively fusing successive layers of powdered material using a CO2 laser. LS imparts significant advantages over traditional manufacturing techniques including extensive design freedom, the ability to manipulate the local properties of a single material part as well as economical manufacture of bespoke items due to the elimination of tooling. Modifying the mechanical properties and/or geometry of sole units has been shown to provide benefits in the areas of performance, injury risk reduction and comfort, especially when considering elite athletes on a subject specific basis. Given the attributes of LS outlined above, the technology offers significant potential to produce sole units offering high added-value compared to conventional counterparts which are limited by the constraints of traditional processing techniques such as injection moulding. However, the mechanical capacity of LS polymers in context of such application was unknown. Accordingly, this research investigated the suitability of a laser sintered elastomer (LSE) material, in view of key selected mechanical properties, for the manufacture of running shoe midsoles. The midsole is the primary functional component in the sole unit of a running shoe used for distance running on hard surfaces. Following a preliminary assessment of the selected LSE (TPE 210-S), a new dynamic test method was designed to assess the compressive, fatigue and time dependent recovery properties of midsole material specimens under loading conditions representative of in-service use. The method was successfully implemented on an electro-mechanical test apparatus (previously unreported upon in literature) and used firstly, to benchmark the aforementioned properties of a range of ethylene vinyl acetate (EVA) and polyurethane (PU) midsole foams representative of the range currently used in production, and secondly, to establish the same property set for TPE 210-S specimens produced across a range of laser powers (LP's). Initial cycle operating ranges in terms of key compressive properties were established for EVA and PU materials. All conventional variants showed considerable deterioration from these initial values over the 125,000 cycle test regime, but subsequently demonstrated partial recovery when left unloaded post-test. PU grades generally exhibited better fatigue performance and findings were consistent with those of previous studies. Whilst variation in LP facilitated linear variation in displacement and stiffness properties for TPE 210-S, all specimens yielded a stiffer and more elastic response than that of conventional foams at the outset; initial compressive operating ranges, whilst within close proximity, did not overlap. However, fatigue performance was found to be superior with only relatively small property changes occurring over the test regime regardless of LP. Furthermore, no signs of catastrophic specimen failure (e.g. cracking) were visually apparent. In this respect the material showed good suitability for midsole applications, but further work is required to address increasing the available compressive property range which fell outside the scope of this work

The effect of mould temperature on properties of flexible PU Foam

Cold-cure flexible polyurethane (PU) foam moulded products are manufactured by mixing a polyol and an isocyanate in a preheated tool. Foam moulded products frequently have defects such as varying density and surface defects. Defects resulting in scrap amount to 2-4% which translates into millions of pounds. Past research to reduce flexible foam moulding scrap and improve quality has focussed on chemical compositions, chemical reactions and materials development. This research set about understanding and improvement through a manufacturing focus to control and improve the foam moulding process. It was suspected that an uneven mould temperature was among the causes of defects in flexible PU foam parts. However, no detailed published work focusing on the effect of mould temperature on high-resilience cold-cure flexible PU foam moulded parts was found. The aim of this research was to analyse and quantify the effect of mould temperature on flexible PU foam surface texture and density. This could then be used to implement either conformal or non-conformal heating channel systems in foam moulding tools. A specially designed mould was built to produce PU foam samples at varying temperatures from 30°C to 80°C. A unique approach using a 3D Laser scanner and a CT scanner was adopted to analyse and quantify the effect of mould temperature on the PU foam samples surface texture and density. It was shown that mould temperature had an effect on foam surface texture and density. The foam density increased as the mould temperature reduced, and foam surface texture was coarse at extreme low and high mould temperatures. Analysis with SEM also showed that mould temperature had an effect on foam density due to its effect on foam cell size. Low mould temperature resulted in small cell size contributing to high foam density. High mould temperature resulted in large cell size contributing to low foam density. Results from this research provide a method of predicting the effect of mould temperature on foam density and surface texture at varying temperatures. Results provide a possible method for customising foam density at various sections by developing a non-conformal heating channel to impose large mould temperature variations. Designers and manufacturers could have multiple density in car seats (such as dual density bucket design seats) if required by controlling mould temperature at various mould sections rather than by changing material composition

Research priorities for advanced fibrous composites

Priorities for research in advanced laminated fibrous composite materials are presented. Supporting evidence is presented in two bodies, including a general literature survey and a survey of aerospace composite hardware and service experience. Both surveys were undertaken during 1977-1979. Specific results and conclusions indicate that a significant portion of contemporary published research diverges from recommended priorites