Reliability, Safety and Error Recovery for Advanced Control Software

For long-duration automated operation of regenerative life support systems in space environments, there is a need for advanced integration and control systems that are significantly more reliable and safe, and that support error recovery and minimization of operational failures. This presentation outlines some challenges of hazardous space environments and complex system interactions that can lead to system accidents. It discusses approaches to hazard analysis and error recovery for control software and challenges of supporting effective intervention by safety software and the crew

Effects of drought on the production of electrophysiologically active biogenic volatiles important for cereal pest management

Thesis submitted to the Faculty of Science, University of the Witwatersrand, in partial fulfillment of the requirements for the degree PhD Science Johannesburg, September 2014Drought has the potential to reset trophic interactions within natural and managed ecosystems. I tested how drought stress in maize and companion plants that are used in cereal agroecosystems of Kenya affect oviposition preference, larval feeding, and development of the spotted stemborer, Chilo partellus Swinhoe (Lepidoptera: Crambidae). Five host species were tested (all Poaceae): maize (Zea mays L.), Napier grass (Pennisetum purpureum Schumach), signal grass [Brachiaria brizantha (A. Rich) Stapf], Brachiaria cv ‘Mulato’, and molasses grass [Melinis minutiflora (Beauv.)]. Under periods of water deficit, maize was oviposited on as much as under control unstressed maize in both choice and no-choice experiments. Similarly, larval leaf damage was not significantly different in drought-stressed and unstressed maize. However in Napier and signal grasses, oviposition occurred less on drought-stressed than on unstressed corresponding individuals of the same species. Oviposition acceptance and foliar damage remained low in both drought-stressed and unstressed molasses grass and Mulato. Larval survival and development remained high in drought-stressed maize, but not in Napier, signal, and molasses grass and Mulato, where survival and development were low in both drought-stressed and unstressed plants. Drought stress resulted in increased total plant volatile emission in Napier and signal grasses. This significant change in total volatile emission of the plants upon stress was not present in molasses grass, Mulato II, Silverleaf and Greenleaf Desmodium despite variable changes in the quantities and qualities of particular constituent compounds among all the plant species during water deficit. In wind tunnel bioassays, volatile organic compounds (VOCs) from irrigated Napier and signal grasses were more attractive to C. partellus than the treatment plants. However, volatiles from molasses grass, Mulato II, Silverleaf and Greenleaf Desmodium were never preferred by the gravid moths in both irrigated and drought stressed v conditions. These changes in chemical constituents of the plant VOCs also elicited behavioural responses in parasitoids. Drought-stressed Napier grass attracted gravid Cotesia sesamiae parasitoids. Other companion plant species such as molasses grass and Mulato which constitutively emit these terpenes remained attractive to the parasitoids even under periods of drought. I attribute this differential preference of the moths to the constitutive and/or induced emission of key terpenoid compounds in plants that were tested. The induction of terpenoid compounds was coupled with a reduction in the amount of green leaf volatiles such as (Z)-3-hexenyl acetate in Napier and signal grasses. Taken together, the results suggest that control of stemborer pests using stimulo-deterrent diversion tactics remains possible under periods of environmental change

Quantum metrology with a single ytterbium ion optical clock

The thesis focusses on the developments and measurements of the Yb+ optical clock at NPL. During my period there, new ion traps, trap control electronics and optical cavities have been developed. Numerous measurement campaigns have been conducted, where we measured the absolute frequency of both optical clock transitions in Yb+ relative to caesium, for the first time ever directly measured the frequency ratio of these transitions, and performed numerous international comparisons against other optical clocks. The total systematic uncertainty of the clock is now expected to be at the mid-low 10-18 level, with published uncertainty budgets at the mid 10-17 level, making it a strong candidate for a future redefinition of the second. The exotic electron structure of the excited levels in Yb+ make it a promising system for tests of fundamental physics. The frequencies of the transitions used in the Yb+ clock are highly sensitive to changes in the fine structure constant, α, which is predicted to vary by many physical theories beyond the standard model. By combing our absolute frequency measurements with a history of atomic clock measurements, we can place new best limits on the present day time variation of α, and the proton-electron mass ratio, µ

An operational system for subject switching between controlled vocabularies: A computational linguistics approach

The NASA Lexical Dictionary (NLD), a system that automatically translates input subject terms to those of NASA, was developed in four phases. Phase One provided Phrase Matching, a context sensitive word-matching process that matches input phrase words with any NASA Thesaurus posting (i.e., index) term or Use reference. Other Use references have been added to enable the matching of synonyms, variant spellings, and some words with the same root. Phase Two provided the capability of translating any individual DTIC term to one or more NASA terms having the same meaning. Phase Three provided NASA terms having equivalent concepts for two or more DTIC terms, i.e., coordinations of DTIC terms. Phase Four was concerned with indexer feedback and maintenance. Although the original NLD construction involved much manual data entry, ways were found to automate nearly all but the intellectual decision-making processes. In addition to finding improved ways to construct a lexical dictionary, applications for the NLD have been found and are being developed

Design Recovery and Data Mining: A Methodology That Identifies Data-Cohesive Subsystems Based on Mining Association Rules.

Software maintenance is both a technical and an economic concern for organizations. Large software systems are difficult to maintain due to their intrinsic complexity, and their maintenance consumes between 50% and 90% of the cost of their complete life-cycle. An essential step in maintenance is reverse engineering, which focuses on understanding the system. This system understanding is critical to avoid the generation of undesired side effects during maintenance. The objective of this research is to investigate the potential of applying data mining to reverse engineering. This research was motivated by the following: (1) data mining can process large volumes of information, (2) data mining can elicit meaningful information without previous knowledge of the domain, (3) data mining can extract novel non-trivial relationships from a data set, and (4) data mining is automatable. These data mining features are used to help address the problem of understanding large legacy systems. This research produced a general method to apply data mining to reverse engineering, and a methodology for design recovery, called Identification of Subsystems based on Associations (ISA). ISA uses mined association rules from a database view of the subject system to guide a clustering process that produces a data-cohesive hierarchical subsystem decomposition of the system. ISA promotes object-oriented principles because each identified subsystem consists of a set of data repositories and the code (i.e., programs) that manipulates them. ISA is an automatic multi-step process, which uses the source code of the subject system and multiple parameters as its input. ISA includes two representation models (i.e., text-based and graphic-based representation models) to present the resulting subsystem decomposition. The automated environment RE-ISA implements the ISA methodology. RE-ISA was used to produce the subsystem decomposition of real-word software systems. Results show that ISA can automatically produce data-cohesive subsystem decompositions without previous knowledge of the subject system, and that ISA always generates the same results if the same parameters are utilized. This research provides evidence that data mining is a beneficial tool for reverse engineering and provides the foundation for defining methodologies that combine data mining and software maintenance

The effect upon UK energy supply schedules of the use of combined heat and power with district heating

The widescale use of combined heat and power with district heating will have a significant effect upon the quantities of primary and secondary fuels used in the United Kingdom. A new methodology for investigating the complex technological interactions between supplies and demands for fuels is developed, and the effect of sample CHP/dh scenarios calculated. Particular attention is paid to electricity generation to determine the impact of CHP/dh upon the operation of the merit order

Neuroprotective Effects of the Nutraceutical Dehydrozingerone and Its C2-Symmetric Dimer in a Drosophila Model of Parkinson’s Disease

Parkinson’s disease (PD) is a neurodegenerative disorder characterized by the loss of dopaminergic neurons responsible for unintended or uncontrollable movements. Mutations in the leucine-rich repeat kinase 2 locus contribute to genetic forms of PD. The fruit fly Drosophila melanogaster carrying this mutation (LRRK2-Dm) is an in vivo model of PD that develops motor impairment and stands for an eligible non-mammalian paradigm to test novel therapeutic approaches. Dehydrozingerone (DHZ) is a natural phenolic compound isolated from ginger and presents anti-inflammatory, antioxidant and neuroprotective properties, making it a potential therapeutic target for PD. We administered DHZ and its C2-symmetric dimer (DHZ-DIM) at 0.5 and 1 mM for 14 and 21 days in the LRRK2-Dm, with the aim of assessing changes in rescuing motor behavior, brain dopaminergic neurons, mitochondria and synapses (T-bars). The shorter treatment with both molecules revealed efficacy at the higher dose, improving climbing behavior with a prevention of dopaminergic neuronal demise. After 21 days, a recovery of the motor disability, dopaminergic neuron loss, mitochondrial damage and T-bars failure was observed with the DHZ-DIM. Our data indicate that the DHZ-DIM exerts a more potent neuroprotective effect with respect to the monomer in LRRK2-Dm, prompting further investigation of these compounds in rodent models of PD

Monroe Urbanized Area MTP 2035

237 pages. Developed by Alliance Transportation Group, Inc. in association with Neel-Schaffer, Inc. Developed for The Monroe Urbanized Area Metropolitan Planning Organization

Annual reports of the selectmen and other officers of the town of Bradford, New Hampshire, for the year ending December 31, 1984, and vital statistics for the year 1984.

This is an annual report containing vital statistics for a town/city in the state of New Hampshire