1,220 research outputs found

    Real-time application of knowledge-based systems

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    The Rapid Prototyping Facility (RPF) was developed to meet a need for a facility which allows flight systems concepts to be prototyped in a manner which allows for real-time flight test experience with a prototype system. This need was focused during the development and demonstration of the expert system flight status monitor (ESFSM). The ESFSM was a prototype system developed on a LISP machine, but lack of a method for progressive testing and problem identification led to an impractical system. The RPF concept was developed, and the ATMS designed to exercise its capabilities. The ATMS Phase 1 demonstration provided a practical vehicle for testing the RPF, as well as a useful tool. ATMS Phase 2 development continues. A dedicated F-18 is expected to be assigned for facility use in late 1988, with RAV modifications. A knowledge-based autopilot is being developed using the RPF. This is a system which provides elementary autopilot functions and is intended as a vehicle for testing expert system verification and validation methods. An expert system propulsion monitor is being prototyped. This system provides real-time assistance to an engineer monitoring a propulsion system during a flight

    The Gastropod Thais haemastoma in Georgia: T. h. floridana or T. h. canaliculata?

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    In the southeastern United States, the snail Thais haemastoma has traditionally been subdivided into two subspecies according to the snail‘s locale, size of shell, number and size of spines, and depth of suture. Only Thais haemastoma floridana is supposed to occur in Georgia; since Thais haemastoma canaliculata is supposedly restricted to the Gulf of Mexico region. In Georgia, specimens fitting the description of both subspecies are common. The author concurs with the conclusions of Butler (1953) and Gunter (1979) in that the subspecies nomenclature is invalid and that they are merely ecological variants

    The Impact of the Safeguard Anti-Ballistic Missile System Construction on Northeastern North Dakota

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    Federal defense projects have let to rapid population changes in many communities. These communities often have experienced rapid growth during the construction and installation phase, followed by a population decrease when the project became operational and labor requirements declined. Large industrial construction projects (e.g., construction of coal conversion plants) may confront other communities with similar adjustment problems.Community/Rural/Urban Development,

    From an automated flight-test management system to a flight-test engineer's workstation

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    The capabilities and evolution is described of a flight engineer's workstation (called TEST-PLAN) from an automated flight test management system. The concept and capabilities of the automated flight test management systems are explored and discussed to illustrate the value of advanced system prototyping and evolutionary software development

    Johnson Space Center's regenerative life support systems test bed

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    The Regenerative Life Support System (RLSS) Test Bed at NASA's Johnson Space Center is an atmospherically closed, controlled environment facility for the evaluation of regenerative life support systems using higher plants in conjunction with physicochemical life support systems. When completed, the facility will be comprised of two large scale plant growth chambers, each with approximately 10 m(exp 2) growing area. One of the two chambers, the Variable Pressure Growth Chamber (VPGC), will be capable of operating at lower atmospheric pressures to evaluate a range of environments that may be used in Lunar or Martian habitats; the other chamber, the Ambient Pressure Growth Chamber (APGC) will operate at ambient atmospheric pressure. The root zone in each chamber will be configurable for hydroponic or solid state media systems. Research will focus on: (1) in situ resource utilization for CELSS systems, in which simulated lunar soils will be used in selected crop growth studies; (2) integration of biological and physicochemical air and water revitalization systems; (3) effect of atmospheric pressure on system performance; and (4) monitoring and control strategies

    Growth and Production of the Dwarf Surf Clam Mulinia lateralis (Say 1822) in a Georgia Estuary

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    The bivalve Mulinia lateralis is a dominant member of estuarine benthos, but its presence and abundance in Georgia estuarine waters is sporadic over time. Recruitment and production was monitored from 1977 through 1981 at three inner and one outer more saline ( \u3e 18 ppt) areas of Wassaw Sound. Until the winter of 1981, Mulinia lateralis was absent or at very low densities. Significant settlement occurred in January 1981 when densities in the outer sound reached as high as 63,000 individuals • m-2). The clam was more abundant in sandy mud (x̄ = 10,161 • m-2) than mud (x̄=277 • m-2) or sand (x̄=263 • m-2).Cohort production varied from 0.3 g dry wt • m-2 • 4 months-1 in the inner sound to 325 g dry wt • m-2 • 7 months-1 in the outer Sound, with the mean biomass ranging from 0.6 to 513 g dry wt • m-2, respectively. When present, Mulinia lateralis contributes significantly to benthic production available to commercially valuable fish and crabs. That this food resource is annually and seasonally episodic could contribute to year-to-year fluctuations in production of species preying on benthos

    The Effects of Cage Mesh Size and Tidal Level Placement on the Growth and Survival of Clams, Mercenaria mercenaria (L.) and Spisula solidissima (Dillwyn), in the Coastal Waters of Georgia

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    This work reports on the effects of cage mesh size and tidal level placement upon the growth and survival of the hard clam, Mercenarla mercenaria (L.), and the surf clam, Spisula solidissima (Dillwyn), In the coastal waters of Georgia. Surf clams (N = 50 per cage) and hard clams (N = 100 per cage) were each planted in replicated (N = 2) cages constructed of 3 mm, 6 mm, 13 mm and 19 mm mesh vexar plastic at various tidal levels. Cages were deployed by partial burial at the mean and the spring low water marks. At termination of the surf clam trial (6 months), there were no significant differences in survival determined for clams planted in different mesh cages at either tidal level or for clams grown in equivalent mesh size cages between tidal levels. There were significant differences In clam size with surf clams at the spring low water growing significantly larger than those at the mean low water mark. There were also significant differences In surf clam growth between different mesh size cages. Surf clams from 6 mm cages were smaller than those from other cages, while the largest clams reared were in the 13 mm and 19 mm mesh cages. Hard clam trials (15 month duration) illustrated that cage mesh size induced significant differences in survlval of hard clams. Significantly fewer clams survived In 19 mm mesh cages than in cages of smaller mesh at both tidal levels. No significant differences in hard clam survival were detected among other mesh sizes nor between tidal levels; neither were significant differences between tidal levels determined for equivalent mesh sizes. Significant differences in hard clam growth were determined for clams grown in different mesh size cages and between tidal levels. Clam growth was greater at the spring low water mark. Clams grew larger in 3 mm mesh cages, least In 13 mm mesh cages with no significant differences In growth in the 6 and 19 mm mesh cages. Statistical analyses (t-tests) Illustrated differences in clam growth among replicates at the spring low water mark. Growth may have been reduced in one set of cages as a result of cage excavation by currents. In Georgia, hard and surf clam growth was found to be dependent upon cage mesh size. Clam survival was Independent of cage mesh size as long as the initial size of the seed animals was greater than the mesh size of the cage
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