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Sample records for controlled nutrient-limited environments

  1. The expression of stlA in Photorhabdus luminescens is controlled by nutrient limitation.

    Directory of Open Access Journals (Sweden)

    Lea Lango-Scholey

    Full Text Available Photorhabdus is a genus of Gram-negative entomopathogenic bacteria that also maintain a mutualistic association with nematodes from the family Heterorhabditis. Photorhabdus has an extensive secondary metabolism that is required for the interaction between the bacteria and the nematode. A major component of this secondary metabolism is a stilbene molecule, called ST. The first step in ST biosynthesis is the non-oxidative deamination of phenylalanine resulting in the production of cinnamic acid. This reaction is catalyzed by phenylalanine-ammonium lyase, an enzyme encoded by the stlA gene. In this study we show, using a stlA-gfp transcriptional fusion, that the expression of stlA is regulated by nutrient limitation through a regulatory network that involves at least 3 regulators. We show that TyrR, a LysR-type transcriptional regulator that regulates gene expression in response to aromatic amino acids in E. coli, is absolutely required for stlA expression. We also show that stlA expression is modulated by σ(S and Lrp, regulators that are implicated in the regulation of the response to nutrient limitation in other bacteria. This work is the first that describes pathway-specific regulation of secondary metabolism in Photorhabdus and, therefore, our study provides an initial insight into the complex regulatory network that controls secondary metabolism, and therefore mutualism, in this model organism.

  2. Control of lifespan by food bacteria, nutrient limitation and pathogenicity of food in C. elegans.

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    So, Shuhei; Tokumaru, Takaaki; Miyahara, Kohji; Ohshima, Yasumi

    2011-04-01

    The increased lifespan caused by food limitation has been observed in a wide range of animals including the nematode Caenorhabditis elegans. We show here that the lifespans of eat-2 and eat-5 feeding-defective mutants and a mutant of dbl-1 encoding a TGFβ ligand significantly change between the cultures fed on Escherichia coli strain OP50 or a more nutrient-rich strain HB101. On HB101 food, the eat-2, eat-5 and dbl-1 mutants show increased lifespan compared to that of the wild type. This result is probably due to nutrient limitation because the eat mutations reduce food uptake and the mutation of dbl-1 that regulates expression of several digestive enzymes leads to nutrient limitation. In contrast, the lifespans of the eat-2 and dbl-1 mutants decreased from that of the wild type on OP50 food. We found that live OP50 cells within a worm were markedly more in these mutants than in the wild type, which suggests that impaired digestion of pathogenic OP50 decreased lifespan in the eat-2 and dbl-1 mutants.

  3. Nutrient Limitation of Microbial Mediated Decomposition and Arctic Soil Chronology

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    Melle, C. J.; Darrouzet-Nardi, A.; Wallenstein, M. D.

    2012-12-01

    Soils of northern permafrost regions currently contain twice as much carbon as the entire Earth's atmosphere. Traditionally, environmental constraints have limited microbial activity resulting in restricted decomposition of soil organic matter in these systems and accumulation of massive amounts of soil organic carbon (SOC), however climate change is reducing the constraints of decomposition in arctic permafrost regions. Carbon cycling in nutrient poor, arctic ecosystems is tightly coupled to other biogeochemical cycles. Several studies have suggested strong nitrogen limitations of primary productivity and potentially warm-season microbial activity in these nutrient deficient soils. Nitrogen is required for microbial extracellular enzyme production which drives the decomposition of soil organic matter (SOM). Nitrogen limited arctic soils may also experience limitation via labile carbon availability despite the SOM rich environment due to low extracellular enzyme production. Few studies have directly addressed nutrient induced microbial limitation in SOC rich arctic tundra soils, and even less is known about the potential for nutrient co-limitation. Additionally, through the process of becoming deglaciated, sites within close proximity to one another may have experienced drastic differences in their effective soil ages due to the varied length of their active histories. Many soil properties and nutrient deficiencies are directly related to soil age, however this chronology has not previously been a focus of research on nutrient limitation of arctic soil microbial activity. Understanding of nutrient limitations, as well as potential co-limitation, on arctic soil microbial activity has important implications for carbon cycling and the ultimate fate of the current arctic SOC reservoir. Analyses of nutrient limitation on soils of a single site are not adequate for fully understanding the controls on soil microbial activity across a vast land mass with large variation in

  4. Nutrient Limitation in Central Red Sea Mangroves

    KAUST Repository

    Almahasheer, Hanan

    2016-12-24

    As coastal plants that can survive in salt water, mangroves play an essential role in large marine ecosystems (LMEs). The Red Sea, where the growth of mangroves is stunted, is one of the least studied LMEs in the world. Mangroves along the Central Red Sea have characteristic heights of ~2 m, suggesting nutrient limitation. We assessed the nutrient status of mangrove stands in the Central Red Sea and conducted a fertilization experiment (N, P and Fe and various combinations thereof) on 4-week-old seedlings of Avicennia marina to identify limiting nutrients and stoichiometric effects. We measured height, number of leaves, number of nodes and root development at different time periods as well as the leaf content of C, N, P, Fe, and Chl a in the experimental seedlings. Height, number of nodes and number of leaves differed significantly among treatments. Iron treatment resulted in significantly taller plants compared with other nutrients, demonstrating that iron is the primary limiting nutrient in the tested mangrove population and confirming Liebig\\'s law of the minimum: iron addition alone yielded results comparable to those using complete fertilizer. This result is consistent with the biogenic nature of the sediments in the Red Sea, which are dominated by carbonates, and the lack of riverine sources of iron.

  5. Plants adapted to nutrient limitation allocate less biomass into stems in an arid-hot grassland.

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    Yan, Bangguo; Ji, Zhonghua; Fan, Bo; Wang, Xuemei; He, Guangxiong; Shi, Liangtao; Liu, Gangcai

    2016-09-01

    Biomass allocation can exert a great influence on plant resource acquisition and nutrient use. However, the role of biomass allocation strategies in shaping plant community composition under nutrient limitations remains poorly addressed. We hypothesized that species-specific allocation strategies can affect plant adaptation to nutrient limitations, resulting in species turnover and changes in community-level biomass allocations across nutrient gradients. In this study, we measured species abundance and the concentrations of nitrogen and phosphorus in leaves and soil nutrients in an arid-hot grassland. We quantified species-specific allocation parameters for stems vs leaves based on allometric scaling relationships. Species-specific stem vs leaf allocation parameters were weighted with species abundances to calculate the community-weighted means driven by species turnover. We found that the community-weighted means of biomass allocation parameters were significantly related to the soil nutrient gradient as well as to leaf stoichiometry, indicating that species-specific allocation strategies can affect plant adaptation to nutrient limitations in the studied grassland. Species that allocate less to stems than leaves tend to dominate nutrient-limited environments. The results support the hypothesis that species-specific allocations affect plant adaptation to nutrient limitations. The allocation trade-off between stems and leaves has the potential to greatly affect plant distribution across nutrient gradients.

  6. Growth phase- and nutrient limitation-associated transcript abundance regulation in Bordetella pertussis.

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    Nakamura, Mari M; Liew, Sin-Yee; Cummings, Craig A; Brinig, Mary M; Dieterich, Christine; Relman, David A

    2006-10-01

    To survive in a host environment, microbial pathogens must sense local conditions, including nutrient availability, and adjust their growth state and virulence functions accordingly. No comprehensive investigation of growth phase-related gene regulation in Bordetella pertussis has been reported previously. We characterized changes in genome-wide transcript abundance of B. pertussis as a function of growth phase and availability of glutamate, a key nutrient for this organism. Using a Bordetella DNA microarray, we discovered significant changes in transcript abundance for 861 array elements during the transition from log phase to stationary phase, including declining transcript levels of many virulence factor genes. The responses to glutamate depletion exhibited similarities to the responses induced by exit from log phase, including decreased virulence factor transcript levels. However, only 23% of array elements that showed at least a fourfold growth phase-associated difference in transcript abundance also exhibited glutamate depletion-associated changes, suggesting that nutrient limitation may be one of several interacting factors affecting gene regulation during stationary phase. Transcript abundance patterns of a Bvg+ phase-locked mutant revealed that the BvgAS two-component regulatory system is a key determinant of growth phase- and nutrient limitation-related transcriptional control. Several adhesin genes exhibited lower transcript abundance during stationary phase and under glutamate restriction conditions. The predicted bacterial phenotype was confirmed: adherence to bronchoepithelial cells decreased 3.3- and 4.4-fold at stationary phase and with glutamate deprivation, respectively. Growth phase and nutrient availability may serve as cues by which B. pertussis regulates virulence according to the stage of infection or the location within the human airway.

  7. Environmental variability drives rapid and dramatic changes in nutrient limitation of tropical macroalgae with different ecological strategies

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    Clausing, Rachel J.; Fong, Peggy

    2016-06-01

    Nitrogen (N) or phosphorus (P) limits primary productivity in nearly every ecosystem worldwide, yet how limitation changes over time, particularly in connection to variation in environmental drivers, remains understudied. We evaluated temporal and species-specific variability in the relative importance of N and P limitation among tropical macroalgae in two-factor experiments conducted twice after rains and twice after dry conditions to explore potential linkages to environmental drivers. We studied three common macroalgal species with varying ecological strategies: a fast-growing opportunist, Dictyota bartayresiana; and two calcifying species likely to be slower growing, Galaxaura fasciculata and Padina boryana. On the scale of days to weeks, nutrient responses ranged among and within species from no limitation to increases in growth by 20 and 40 % over controls in 3 d with N and P addition, respectively. After light rain or dry conditions, Dictyota grew rapidly (up to ~60 % in 3 d) with little indication of nutrient limitation, while Padina and Galaxaura shifted between N, P, or no limitation. All species grew slowly or lost mass after a large storm, presumably due to unfavorable conditions on the reef prior to the experiment that limited nutrient uptake. Padina and Galaxaura both became nutrient limited 3 d post-storm, while Dictyota did not. These results suggest that differing capabilities for nutrient uptake and storage dictate the influence of nutrient history and thus drive nutrient responses and, in doing so, may allow species with differing ecological strategies to coexist in a fluctuating environment. Moreover, the great variability in species' responses indicates that patterns of nutrient limitation are more complex than previously recognized, and generalizations about N versus P limitation of a given system may not convey the inherent complexity in governing conditions and processes.

  8. Evaluation of nutrient limitation in aquatic ecosystems with nitrogen fixing bacteria

    Institute of Scientific and Technical Information of China (English)

    WU Gen-fu; WU Xue-chang; XUAN Xiao-dong; ZHOU Xue-ping

    2006-01-01

    There has always been a great need for simple and accurate bioassays for evaluating nutrient limitation in aquatic ecosystems. Whereas organic carbon is usually considered to be the limiting nutrient for microbial growth in many aquatic ecosystems,there are, however, many water sources that are limited by phosphorus or nitrogen. A method named "nitrogen fixing bacterial growth potential" (NFBGP) test, which is based on pre-culturing ofautochthonous (target) microorganisms was described. The method was applied to evaluate phosphorus or nitrogen nutrient limitation in lake and sewage water samples using an isolate of the nitrogen fixing bacterium, Azorhizobium sp. WS6. The results corresponded well to those from the traditional algal growth potential (AGP) test and the bacterial regrowth potential (BRP) test, suggesting that the NFBGP test is a useful supplementary method for evaluating the limiting nutrient, especially phosphorus, in an aquatic environment.

  9. Multiple independent constraints help resolve net ecosystem carbon exchange under nutrient limitation

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    Thornton, P. E.; Metcalfe, D.; Oren, R.; Ricciuto, D. M.

    2014-12-01

    The magnitude, spatial distribution, and variability of land net ecosystem exchange of carbon (NEE) are important determinants of the trajectory of atmospheric carbon dioxide concentration. Independent observational constraints provide important clues regarding NEE and its component fluxes, with information available at multiple spatial scales: from cells, to leaves, to entire organisms and collections of organisms, to complex landscapes and up to continental and global scales. Experimental manipulations, ecosystem observations, and process modeling all suggest that the components of NEE (photosynthetic gains, and respiration and other losses) are controlled in part by the availability of mineral nutrients, and that nutrient limitation is a common condition in many biomes. Experimental and observational constraints at different spatial scales provide a complex and sometimes puzzling picture of the nature and degree of influence of nutrient availability on carbon cycle processes. Photosynthetic rates assessed at the cellular and leaf scales are often higher than the observed accumulation of carbon in plant and soil pools would suggest. We infer that a down-regulation process intervenes between carbon uptake and plant growth under conditions of nutrient limitation, and several down-regulation mechanisms have been hypothesized and tested. A recent evaluation of two alternative hypotheses for down-regulation in the light of whole-plant level flux estimates indicates that some plants take up and store extra carbon, releasing it to the environment again on short time scales. The mechanism of release, either as additional autotrophic respiration or as exudation belowground is unclear, but has important consequences for long-term ecosystem state and response to climate change signals. Global-scale constraints from atmospheric concentration and isotopic composition data help to resolve this question, ultimately focusing attention on land use fluxes as the most uncertain

  10. Detecting terrestrial nutrient limitation: a global meta-analysis of foliar nutrient concentrations after fertilization

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    Ostertag, Rebecca; DiManno, Nicole

    2016-03-01

    Examining foliar nutrient concentrations after fertilization provides an alternative method for detecting nutrient limitation of ecosystems, which is logistically simpler to measure than biomass change. We present a meta-analysis of response ratios of foliar nitrogen and phosphorus (RRN, RRP) after addition of fertilizer of nitrogen (N), phosphorus (P), or the two elements in combination, in relation to climate, ecosystem type, life form, family, and methodological factors. Results support other meta-analyses using biomass, and demonstrate there is strong evidence for nutrient limitation in natural communities. However, because N fertilization experiments greatly outnumber P fertilization trials, it is difficult to discern the absolute importance of N vs. P vs. co-limitation across ecosystems. Despite these caveats, it is striking that results did not follow "conventional wisdom" that temperate ecosystems are N-limited and tropical ones are P-limited. In addition, the use of ratios of N-to-P rather than response ratios also are a useful index of nutrient limitation, but due to large overlap in values, there are unlikely to be universal cutoff values for delimiting N vs. P limitation. Differences in RRN and RRP were most significant across ecosystem types, plant families, life forms, and between competitive environments, but not across climatic variables.

  11. Stoichiometry, Metabolism and Nutrient Limitation Across the Periodic Table in Natural Flowing-Water Chemostats

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    Cohen, M. J.; Nifong, R. L.; Kurz, M. J.; Cropper, W. P.; Martin, J. B.

    2014-12-01

    Relative supplies of macro and micronutrients (C,N,P, various metals), along with light and water, controls ecosystem metabolism, trophic energy transfer and community structure. Here we test the hypothesis, using measurements from 41 spring-fed rivers in Florida, that tissue stoichiometry indicates autotroph nutrient limitation status. Low variation in discharge, temperature and chemical composition within springs, but large variation across springs creates an ideal setting to assess the relationship between limitation and resource supply. Molar N:P ranges from 0.4 to 90, subjecting autotrophs to dramatically different nutrient supply. Over this gradient, species-specific autotroph tissue C:N:P ratios are strictly homeostatic, and with no evidence that nutrient supply affects species composition. Expanding to include 19 metals and micronutrients revealed autotrophs are more plastic in response to micronutrient variation, particularly for iron and manganese whose supply fluxes are small compared to biotic demand. Using a Droop model modified to reflect springs conditions (benthic production, light limitation, high hydraulic turnover), we show that tissue stoichiometry transitions from homeostatic to plastic with the onset of nutrient limitation, providing a potentially powerful new tool for predicting nutrient limitation and thus eutrophication in flowing waters.

  12. Controlled Environment Specimen Transfer

    DEFF Research Database (Denmark)

    Damsgaard, Christian Danvad; Zandbergen, Henny W.; Hansen, Thomas Willum

    2014-01-01

    Specimen transfer under controlled environment conditions, such as temperature, pressure, and gas composition, is necessary to conduct successive complementary in situ characterization of materials sensitive to ambient conditions. The in situ transfer concept is introduced by linking an environme...

  13. Environment induced incoherent controllability

    OpenAIRE

    Romano, Raffaele; D'Alessandro, Domenico

    2005-01-01

    We prove that the environment induced entanglement between two non interacting, two-dimensional quantum systems S and P can be used to control the dynamics of S by means of the initial state of P. Using a simple, exactly solvable model, we show that both accessibility and controllability of S can be achieved under suitable conditions on the interaction of S and P with the environment.

  14. Substrate and nutrient limitation regulating microbial growth in soil

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    Bååth, Erland

    2015-04-01

    Microbial activity and growth in soil is regulated by several abiotic factors, including temperature, moisture and pH as the most important ones. At the same time nutrient conditions and substrate availability will also determine microbial growth. Amount of substrate will not only affect overall microbial growth, but also affect the balance of fungal and bacterial growth. The type of substrate will also affect the latter. Furthermore, according to Liebig law of limiting factors, we would expect one nutrient to be the main limiting one for microbial growth in soil. When this nutrient is added, the initial second liming factor will become the main one, adding complexity to the microbial response after adding different substrates. I will initially describe different ways of determining limiting factors for bacterial growth in soil, especially a rapid method estimating bacterial growth, using the leucine incorporation technique, after adding C (as glucose), N (as ammonium nitrate) and P (as phosphate). Scenarios of different limitations will be covered, with the bacterial growth response compared with fungal growth and total activity (respiration). The "degree of limitation", as well as the main limiting nutrient, can be altered by adding substrate of different stoichiometric composition. However, the organism group responding after alleviating the nutrient limitation can differ depending on the type of substrate added. There will also be situations, where fungi and bacteria appear to be limited by different nutrients. Finally, I will describe interactions between abiotic factors and the response of the soil microbiota to alleviation of limiting factors.

  15. Microbial phosphorous mobilization strategies across a natural nutrient limitation gradient

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    Walker, R.; Wang, S.; Nico, P. S.; Fox, P. M.; Hao, Z.; Karaoz, U.; Torok, T.; Brodie, E.; Chakraborty, R.; Hao, Z.

    2016-12-01

    Phosphorus (P) is a critical nutrient and frequently limits primary productivity in terrestrial ecosystems. Microorganisms have evolved an array of strategies to mobilize occluded and insoluble P and may be important regulators of P availability to vegetation. Understanding the mechanisms of P mobilization, the breadth of microorganisms responsible, and the impact of these organisms on vegetation growth remains an important knowledge gap for both predicting ecosystem productivity and harnessing microbial functions to improve vegetation growth. To determine the relationship between soil development, phosphorus availability and P mobilizing microorganisms and their strategies we are studying a marine terrace chronosequence (Ecological Staircase, Mendocino County, CA) representing a fertility gradient culminating in P-limited pygmy forests that provide an ideal natural observatory to investigate how plant-microbe interactions co-evolve in response to P stress. Soil mineralogical analysis identified acidic soils bearing iron and aluminum phosphates and phytate as the dominant forms of occluded inorganic and organic P, respectively. Several diverse bacterial and fungal strains were isolated on media with AlPO4, FePO4, or phytate as the sole P source. Most microorganisms were able to utilize AlPO4 as a sole P source, with fewer subsisting on FePO4 or phytate. Terraces with a higher fraction of occluded and organic P harbored the greatest abundance of P-mobilizing microorganisms, with a significant proportion coming from the Burkholderia. Isolates that exhibited significant excess P mobilization were inoculated with Arabidopsis and Switchgrass plants grown with insoluble P forms had a positive impact on growth. These results indicate that rhizosphere microorganisms that have evolved under extreme nutrient limitation have an extended capacity for P solubilization, and could potentially be harnessed to alleviate P stress for plants. The detailed mechanisms for P

  16. Individually Controlled Indoor Environment

    DEFF Research Database (Denmark)

    Melikov, Arsen Krikor

    2004-01-01

    individual differences in physiological and psychological response, clothing insulation, activity, preference for air temperature and movement, etc., exist between people. Environmental conditions acceptable for most of the occupants in buildings may be achieved by providing each occupant......The thermal environment and inhaled air quality in buildings to which occupants are exposed has an effect on their health, comfort, performance and productivity. Heating, ventilating and air-conditioning (HVAC) of buildings today is designed to provide a uniform environment. However, large...... knowledge on human response to an individually controlled microenvironment. Recently developed new principles and methods for individually controlled local heating and clean air distribution aimed at improving occupants¿ comfort and performance, as well as protection of occupants from airborne transmission...

  17. Nutrient limitations in wet, drained and rewetted fen meadows : evaluation of methods and results

    NARCIS (Netherlands)

    Van Duren, IC; Pegtel, DM

    2000-01-01

    Restoration of wet grassland communities on peat soils involves management of nutrient supply and hydrology. The concept of nutrient limitation was discussed as well as its interaction with drainage and rewetting of severely drained peat soils. Different methods of assessing nutrient limitation were

  18. Fast Detection of Nutrient Limitation in Macroalgae and Seagrass with Nutrient-Induced Fluorescence

    NARCIS (Netherlands)

    den Haan, J.; Huisman, J.; Dekker, F.; ten Brinke, J.L.; Ford, A.K.; van Ooijen, J.; van Duyl, F.C.; Vermeij, M.J.A.; Visser, P.M.

    2013-01-01

    Background: Rapid determination of which nutrients limit the primary production of macroalgae and seagrasses is vital for understanding the impacts of eutrophication on marine and freshwater ecosystems. However, current methods to assess nutrient limitation are often cumbersome and time consuming. F

  19. Nutrients Limiting Soybean (glycine max l) Growth in Acrisols and Ferralsols of Western Kenya.

    Science.gov (United States)

    Keino, Ludy; Baijukya, Frederick; Ng'etich, Wilson; Otinga, Abigael N; Okalebo, John R; Njoroge, Ruth; Mukalama, John

    2015-01-01

    Low soybean yields in western Kenya have been attributed to low soil fertility despite much work done on nitrogen (N) and phosphorus (P) nutrition leading to suspicion of other nutrient limitations. To investigate this, a nutrient omission trial was set up in the greenhouse at the University of Eldoret-Kenya to diagnose the nutrients limiting soybean production in Acrisols from Masaba central and Butere sub-Counties, and Ferralsols from Kakamega (Shikhulu and Khwisero sub-locations) and Butula sub-Counties and to assess the effect of liming on soil pH and soybean growth. The experiment was laid out in a completely randomized design with ten treatments viz; positive control (complete), negative control (distilled water), complete with lime, complete with N, minus macronutrients P, potassium (K), calcium (Ca), magnesium (Mg) and sulphur (S) and with, micro-nutrients boron (B), molybdenum (Mo), manganese (Mn), copper (Cu) and zinc (Zn) omitted. Visual deficiency symptoms observed included interveinal leaf yellowing in Mg omission and N addition and dark green leaves in P omission. Nutrients omission resulted in their significantly low concentration in plant tissues than the complete treatment. Significantly (P≤ 0.05) lower shoot dry weights (SDWs) than the complete treatment were obtained in different treatments; omission of K and Mg in Masaba and Shikhulu, Mg in Khwisero, K in Butere and, P, Mg and K in Butula. Nitrogen significantly improved SDWs in soils from Kakamega and Butula. Liming significantly raised soil pH by 9, 13 and 11% from 4.65, 4.91 and 4.99 in soils from Masaba, Butere and Butula respectively and soybean SDWs in soils from Butere. The results show that, poor soybean growth was due to K, Mg and P limitation and low pH in some soils. The results also signify necessity of application of small quantities of N for initial soybean use.

  20. Nutrients Limiting Soybean (glycine max l Growth in Acrisols and Ferralsols of Western Kenya.

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    Ludy Keino

    Full Text Available Low soybean yields in western Kenya have been attributed to low soil fertility despite much work done on nitrogen (N and phosphorus (P nutrition leading to suspicion of other nutrient limitations. To investigate this, a nutrient omission trial was set up in the greenhouse at the University of Eldoret-Kenya to diagnose the nutrients limiting soybean production in Acrisols from Masaba central and Butere sub-Counties, and Ferralsols from Kakamega (Shikhulu and Khwisero sub-locations and Butula sub-Counties and to assess the effect of liming on soil pH and soybean growth. The experiment was laid out in a completely randomized design with ten treatments viz; positive control (complete, negative control (distilled water, complete with lime, complete with N, minus macronutrients P, potassium (K, calcium (Ca, magnesium (Mg and sulphur (S and with, micro-nutrients boron (B, molybdenum (Mo, manganese (Mn, copper (Cu and zinc (Zn omitted. Visual deficiency symptoms observed included interveinal leaf yellowing in Mg omission and N addition and dark green leaves in P omission. Nutrients omission resulted in their significantly low concentration in plant tissues than the complete treatment. Significantly (P≤ 0.05 lower shoot dry weights (SDWs than the complete treatment were obtained in different treatments; omission of K and Mg in Masaba and Shikhulu, Mg in Khwisero, K in Butere and, P, Mg and K in Butula. Nitrogen significantly improved SDWs in soils from Kakamega and Butula. Liming significantly raised soil pH by 9, 13 and 11% from 4.65, 4.91 and 4.99 in soils from Masaba, Butere and Butula respectively and soybean SDWs in soils from Butere. The results show that, poor soybean growth was due to K, Mg and P limitation and low pH in some soils. The results also signify necessity of application of small quantities of N for initial soybean use.

  1. Nutrients Limiting Soybean (glycine max l) Growth in Acrisols and Ferralsols of Western Kenya

    OpenAIRE

    Ludy Keino; Frederick Baijukya; Wilson Ng'etich; Otinga, Abigael N.; Okalebo, John R.; Ruth Njoroge; John Mukalama

    2015-01-01

    Low soybean yields in western Kenya have been attributed to low soil fertility despite much work done on nitrogen (N) and phosphorus (P) nutrition leading to suspicion of other nutrient limitations. To investigate this, a nutrient omission trial was set up in the greenhouse at the University of Eldoret-Kenya to diagnose the nutrients limiting soybean production in Acrisols from Masaba central and Butere sub-Counties, and Ferralsols from Kakamega (Shikhulu and Khwisero sub-locations) and Butul...

  2. Characterization of Pseudomonas putida Genes Responsive to Nutrient Limitation

    Energy Technology Data Exchange (ETDEWEB)

    Syn, Chris K.; Magnuson, Jon K.; Kingsley, Mark T.; Swarup, Sanjay

    2004-06-01

    The low bioavailability of nutrients and oxygen in the soil environment has hampered successful expression of biodegradation/biocontrol genes that are driven by promoters highly active during routine laboratory conditions of high nutrient- and oxygen-availability. Hence, in the present study, expression of the gus-tagged genes in 12 Tn5-gus mutants of the soil microbe Pseudomonas putida PNL-MK25 was examined under various conditions chosen to mimic the soil environment: low carbon, phosphate, nitrate, or oxygen, and in the rhizosphere. Based on their expression profiles, three nutrient-responsive mutant (NRM) strains, NRM5, NRM7, and NRM17, were selected for identification of the tagged genes. In the mutant strain NRM5, expression of the glutamate dehydrogenase (gdhA) gene was increased between 4.9- to 26.4-fold under various low nutrient conditions. In NRM7, expression of the novel NADPH:quinone oxidoreductase-like (nql) gene was consistently amongst the highest and was synergistically upregulated by low nutrient and anoxic conditions. The cyoD gene in NRM17, which encodes the fourth subunit of the cytochrome o ubiquinol oxidase complex, had decreased expression in low nutrient conditions but its absolute expression levels was still amongst the highest. Additionally, it was independent of oxygen availability, in contrast to that in E. coli.

  3. Minerals as Ecosystems in the Nutrient-Limited Subsurface

    Science.gov (United States)

    Jones, A. A.; Bennett, P.

    2014-12-01

    A majority of microorganisms in dark, nutrient-poor, subsurface habitats live in biofilms attached to mineral surfaces. As a result, microorganisms have likely adapted and evolved to take advantage of specific minerals that support a variety of biogeochemical processes. Using biofilm reactors inoculated with a diverse microbial biomat from a sulfidic cave, we found that specific microorganisms colonize specific minerals according to their metabolic/nutritional requirements as well as their environmental tolerances in order to increase survival in unfavorable environments. In a neutral pH, carbon (C) and phosphate (P)-limited (unfavorable) reactor, highly-buffering carbonates were colonized by nearly identical communities of neutrophilic sulfur-oxidizing (acid-generating) bacteria (SOB), which intensely corroded the carbonates. Non-buffering quartz was colonized by acid-generating acidophiles, while feldspars (containing potentially toxic aluminum) were colonized largely by aluminotolerant microbes. The SOB Thiothrix unzii demonstrated a clear affinity for basalt, and it is commonly found on basaltic rocks in mid-ocean ridge environments. In an identical reactor amended with acetate, heterotrophic sulfur-reducing bacteria (SRB) dominated on most surfaces. The metabolism of the SRB causes an increase in both alkalinity and pH, nearly eliminating the need for buffering minerals and resulting in carbonate precipitation. However, SRB were not dominant on quartz, which was again colonized by acidophiles and acid-tolerant microorganisms or basalt which hosted a complex consortium similar to those found on natural basalt outcrops. These organisms have been shown to weather basalts to access mineral nutrients, especially when provided a carbon source. In both the C&P-limited and acetate-amended reactors significantly greater biomass accumulated on minerals with high P content. When abundant P was added and the pH was buffered to 8.3, mineral selectivity was eliminated and

  4. Invasive fishes generate biogeochemical hotspots in a nutrient-limited system.

    Directory of Open Access Journals (Sweden)

    Krista A Capps

    Full Text Available Fishes can play important functional roles in the nutrient dynamics of freshwater systems. Aggregating fishes have the potential to generate areas of increased biogeochemical activity, or hotspots, in streams and rivers. Many of the studies documenting the functional role of fishes in nutrient dynamics have focused on native fish species; however, introduced fishes may restructure nutrient storage and cycling freshwater systems as they can attain high population densities in novel environments. The purpose of this study was to examine the impact of a non-native catfish (Loricariidae: Pterygoplichthys on nitrogen and phosphorus remineralization and estimate whether large aggregations of these fish generate measurable biogeochemical hotspots within nutrient-limited ecosystems. Loricariids formed large aggregations during daylight hours and dispersed throughout the stream during evening hours to graze benthic habitats. Excretion rates of phosphorus were twice as great during nighttime hours when fishes were actively feeding; however, there was no diel pattern in nitrogen excretion rates. Our results indicate that spatially heterogeneous aggregations of loricariids can significantly elevate dissolved nutrient concentrations via excretion relative to ambient nitrogen and phosphorus concentrations during daylight hours, creating biogeochemical hotspots and potentially altering nutrient dynamics in invaded systems.

  5. Nutrient limitation in Northern Gulf of Mexico (NGOM: phytoplankton communities and photosynthesis respond to nutrient pulse.

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    Yan Zhao

    Full Text Available Although the Mississippi-Atchafalaya River system exports large amounts of nutrients to the Northern Gulf of Mexico annually, nutrient limitation of primary productivity still occurs offshore, acting as one of the major factors controlling local phytoplankton biomass and community structure. Bioassays were conducted for 48 hrs at two stations adjacent to the river plumes in April and August 2012. High Performance of Liquid Chromatography (HPLC combined with ChemTax and a Fluorescence Induction and Relaxation (FIRe system were combined to observe changes in the phytoplankton community structure and photosynthetic activity. Major fluorescence parameters (Fo, Fv/Fm performed well to reveal the stimulating effect of the treatments with nitrogen (N-nitrate and with nitrogen plus phosphate (+NPi. HPLC/ChemTax results showed that phytoplankton community structure shifted with nitrate addition: we observed an increase in the proportion of diatoms and prasinophytes and a decrease in cyanobacteria and prymnesiophytes. These findings are consistent with predictions from trait-based analysis which predict that phytoplankton groups with high maximum growth rates (μmax and high nutrient uptake rates (Vmax readily take advantage of the addition of limiting nutrients. Changes in phytoplankton community structure, if persistent, could trigger changes of particular organic matter fluxes and alter the micro-food web cycles and bottom oxygen consumption.

  6. Drug susceptibility and biofilm formation of Burkholderia pseudomallei in nutrient-limited condition.

    Science.gov (United States)

    Anutrakunchai, C; Sermswan, R W; Wongratanacheewin, S; Puknun, A; Taweechaisupapong, S

    2015-06-01

    Burkholderia pseudomallei is the causative agent of melioidosis, which can form biofilms and microcolonies in vivo and in vitro. One of the hallmark characteristics of the biofilm-forming bacteria is that they can be up to 1,000 times more resistant to antibiotics than their free-living counterpart. Bacteria also become highly tolerant to antibiotics when nutrients are limited. One of the most important causes of starvation induced tolerance in vivo is biofilm growth. However, the effect of nutritional stress on biofilm formation and drug tolerance of B. pseudomallei has never been reported. Therefore, this study aims to determine the effect of nutrient-limited and enriched conditions on drug susceptibility of B. pseudomallei in both planktonic and biofilm forms in vitro using broth microdilution method and Calgary biofilm device, respectively. The biofilm formation of B. pseudomallei in nutrient-limited and enriched conditions was also evaluated by a modified microtiter-plate test. Six isolates of ceftazidime (CAZ)-susceptible and four isolates of CAZ-resistant B. pseudomallei were used. The results showed that the minimum bactericidal concentrations of CAZ against B. pseudomallei in nutrient-limited condition were higher than those in enriched condition. The drug susceptibilities of B. pseudomallei biofilm in both enriched and nutrient-limited conditions were more tolerant than those of planktonic cells. Moreover, the quantification of biofilm formation by B. pseudomallei in nutrient-limited condition was significantly higher than that in enriched condition. These data indicate that nutrient-limited condition could induce biofilm formation and drug tolerance of B. pseudomallei.

  7. Lake and watershed characteristics rather than climate influence nutrient limitation in shallow lakes

    NARCIS (Netherlands)

    Kosten, S.; Huszar, V.M.; Mazzeo, N.; Scheffer, M.; Sternberg, L.S.L.; Jeppesen, E.

    2009-01-01

    Both nitrogen (N) and phosphorus (P) can limit primary production in shallow lakes, but it is still debated how the importance of N and P varies in time and space. We sampled 83 shallow lakes along a latitudinal gradient (5°–55° S) in South America and assessed the potential nutrient limitation usin

  8. The growth responses of coastal dune species are determined by nutrient limitation and sand burial.

    Science.gov (United States)

    Gilbert, Matthew; Pammenter, Norman; Ripley, Brad

    2008-05-01

    Past work suggests that burial and low nutrient availability limit the growth and zonal distribution of coastal dune plants. Given the importance of these two factors, there is a surprising lack of field investigations of the interactions between burial and nutrient availability. This study aims to address this issue by measuring the growth responses of four coastal dune plant species to these two factors and their interaction. Species that naturally experience either high or low rates of burial were selected and a factorial burial by nutrient addition experiment was conducted. Growth characteristics were measured in order to determine which characteristics allow a species to respond to burial. Species that naturally experience high rates of burial (Arctotheca populifolia and Scaevola plumieri) displayed increased growth when buried, and this response was nutrient-limited. Stable-dune species had either small (Myrica cordifolia, N-fixer) or negligible responses to burial (Metalasia muricata), and were not nutrient-limited. This interspecific difference in response to burial and/or fertiliser is consistent with the idea that burial maintains the observed zonation of species on coastal dunes. Species that are unable to respond to burial are prevented from occupying the mobile dunes. Species able to cope with high rates of burial had high nitrogen-use efficiencies and low dry mass costs of production, explaining their ability to respond to burial under nutrient limitation. The interaction between burial and nutrient limitation is understudied but vital to understanding the zonation of coastal dune plant species.

  9. Nutrient Limitation in Surface Waters of the Oligotrophic Eastern Mediterranean Sea: an Enrichment Microcosm Experiment

    KAUST Repository

    Tsiola, A.

    2015-12-01

    The growth rates of planktonic microbes in the pelagic zone of the Eastern Mediterranean Sea are nutrient limited, but the type of limitation is still uncertain. During this study, we investigated the occurrence of N and P limitation among different groups of the prokaryotic and eukaryotic (pico-, nano-, and micro-) plankton using a microcosm experiment during stratified water column conditions in the Cretan Sea (Eastern Mediterranean). Microcosms were enriched with N and P (either solely or simultaneously), and the PO4 turnover time, prokaryotic heterotrophic activity, primary production, and the abundance of the different microbial components were measured. Flow cytometric and molecular fingerprint analyses showed that different heterotrophic prokaryotic groups were limited by different nutrients; total heterotrophic prokaryotic growth was limited by P, but only when both N and P were added, changes in community structure and cell size were detected. Phytoplankton were N and P co-limited, with autotrophic pico-eukaryotes being the exception as they increased even when only P was added after a 2-day time lag. The populations of Synechococcus and Prochlorococcus were highly competitive with each other; Prochlorococcus abundance increased during the first 2 days of P addition but kept increasing only when both N and P were added, whereas Synechococcus exhibited higher pigment content and increased in abundance 3 days after simultaneous N and P additions. Dinoflagellates also showed opportunistic behavior at simultaneous N and P additions, in contrast to diatoms and coccolithophores, which diminished in all incubations. High DNA content viruses, selective grazing, and the exhaustion of N sources probably controlled the populations of diatoms and coccolithophores.

  10. Decoherence control in different environments

    CERN Document Server

    Paavola, Janika

    2010-01-01

    We investigate two techniques for controlling decoherence, focusing on the crucial role played by the environmental spectrum. We show how environments with different spectra lead to very different dynamical behaviours. Our study clearly proves that such differences must be taken into account when designing decoherence control schemes. The two techniques we consider are reservoir engineering and quantum-Zeno control. We focus on a quantum harmonic oscillator initially prepared in a nonclassical state and derive analytically its non-Markovian dynamics in presence of different bosonic thermal environments. On the one hand we show how, by modifying the spectrum of the environment, it is possible to prolong or reduce the life of a Schr\\"odinger cat state. On the other hand we study the effect of nonselective energy measurements on the degradation of quantumness of initial Fock states. In this latter case we see that the crossover between Zeno (QZE) and anti-Zeno (AZE) effects, discussed by Maniscalco et al. [Phys....

  11. Effects of Savanna trees on soil nutrient limitation and carbon-sequestration potential in dry season

    Science.gov (United States)

    Becker, Joscha; Gütlein, Adrian; Sierra Cornejo, Natalia; Kiese, Ralf; Hertel, Dietrich; Kuzyakov, Yakov

    2016-04-01

    Semi-arid savannah ecosystems are under strong pressure from climate and land-use changes, especially around populous areas like Mt. Kilimanjaro region. Savannah vegetation consists of grassland with isolated trees and is therefore characterized by high spatial variation of canopy cover and aboveground biomass. Both are major regulators for soil ecological parameters and soil-atmospheric trace gas exchange (CO2, N2O, CH4), especially in water limited environments. The spatial distribution of these parameters and the connection between above and belowground processes are important to understand and predict ecosystem changes and estimate its vulnerability. Our objective was to determine spatial trends and changes of soil parameters and trace-gas fluxes and relate their variability to the vegetation structure. We chose three trees from each of the two most dominant species (Acacia nilotica and Balanites aegyptiaca). For each tree, we selected transects with total nine sampling points under and outside the crown. At each sampling point we measured soil and plant biomass carbon (C) and nitrogen (N) content, δ13C, microbial biomass C and N, soil respiration, available nutrients, pH, cation exchange capacity (CEC) as well as belowground biomass, soil temperature and soil water content. Contents and stocks of C and N fractions, Ca2+, K+ and total CEC decreased up to 50% outside the crown. This was unaffected by the tree species, tree size or other tree characteristics. Water content was below the permanent wilting point and independent from tree cover. In all cases tree litter inputs had far a closer C:N ratio than C4-grass litter. Microbial C:N ratio and CO2 efflux was about 30% higher in open area and strongly dependent on mineral N availability. This indicates N limitation and low microbial C use efficiency in soil under open area. We conclude that the spatial structure of aboveground biomass in savanna ecosystems leads to a spatial redistribution of nutrient

  12. Quantitative proteomics of nutrient limitation in the hydrogenotrophic methanogen Methanococcus maripaludis

    Directory of Open Access Journals (Sweden)

    Hendrickson Erik L

    2009-07-01

    Full Text Available Abstract Background Methanogenic Archaea play key metabolic roles in anaerobic ecosystems, where they use H2 and other substrates to produce methane. Methanococcus maripaludis is a model for studies of the global response to nutrient limitations. Results We used high-coverage quantitative proteomics to determine the response of M. maripaludis to growth-limiting levels of H2, nitrogen, and phosphate. Six to ten percent of the proteome changed significantly with each nutrient limitation. H2 limitation increased the abundance of a wide variety of proteins involved in methanogenesis. However, one protein involved in methanogenesis decreased: a low-affinity [Fe] hydrogenase, which may dominate over a higher-affinity mechanism when H2 is abundant. Nitrogen limitation increased known nitrogen assimilation proteins. In addition, the increased abundance of molybdate transport proteins suggested they function for nitrogen fixation. An apparent regulon governed by the euryarchaeal nitrogen regulator NrpR is discussed. Phosphate limitation increased the abundance of three different sets of proteins, suggesting that all three function in phosphate transport. Conclusion The global proteomic response of M. maripaludis to each nutrient limitation suggests a wider response than previously appreciated. The results give new insight into the function of several proteins, as well as providing information that should contribute to the formulation of a regulatory network model.

  13. CHARACTERIZATION OF THE TYPE AND EXTENT OF NUTRIENT LIMITATION IN GRASSLAND VEGETATION USING A BIOASSAY WITH INTACT SODS

    NARCIS (Netherlands)

    OLFF, H; PEGTEL, DM

    1994-01-01

    An important methodological problem in plant ecology concerns the way in which the type and extent of nutrient limitation in terrestrial communities should be assessed. Conclusions on nutrient limitation have been founded mainly on soil extractions, fertiliser trials and tissue nutrient concentratio

  14. Evolving Robot Controllers for Structured Environments Through Environment Decomposition

    DEFF Research Database (Denmark)

    Moreno, Rodrigo; Faiña, Andres; Støy, Kasper

    2015-01-01

    show that by using a sequence the evolutionary algorithm can find a controller that performs well in all sub-environments more consistently than when presenting all sub-environments together. We conclude that environment decomposition is an useful approach for evolving controllers for structured......In this paper we aim to develop a controller that allows a robot to traverse an structured environment. The approach we use is to decompose the environment into simple sub-environments that we use as basis for evolving the controller. Specifically, we decompose a narrow corridor environment...... into four different sub-environments and evolve controllers that generalize to traverse two larger environments composed of the sub-environments. We also study two strategies for presenting the sub-environments to the evolutionary algorithm: all sub-environments at the same time and in sequence. Results...

  15. Evolving Robot Controllers for Structured Environments Through Environment Decomposition

    DEFF Research Database (Denmark)

    Moreno, Rodrigo; Faiña, Andres; Støy, Kasper

    2015-01-01

    In this paper we aim to develop a controller that allows a robot to traverse an structured environment. The approach we use is to decompose the environment into simple sub-environments that we use as basis for evolving the controller. Specifically, we decompose a narrow corridor environment into ...

  16. Fine-root responses to fertilization reveal multiple nutrient limitation in a lowland tropical forest.

    Science.gov (United States)

    Wurzburger, Nina; Wright, S Joseph

    2015-08-01

    Questions remain as to which soil nutrients limit primary production in tropical forests. Phosphorus (P) has long been considered the primary limiting element in lowland forests, but recent evidence demonstrates substantial heterogeneity in response to nutrient addition, highlighting a need to understand and diagnose nutrient limitation across diverse forests. Fine-root characteristics including their abundance, functional traits, and mycorrhizal symbionts can be highly responsive to changes in soil nutrients and may help to diagnose nutrient limitation. Here, we document the response of fine roots to long-term nitrogen (N), P, and potassium (K) fertilization in a lowland forest in Panama. Because this experiment has demonstrated that N and K together limit tree growth and P limits fine litter production, we hypothesized that fine roots would also respond to nutrient addition. Specifically we hypothesized that N, P, and K addition would reduce the biomass, diameter, tissue density, and mycorrhizal colonization of fine roots, and increase nutrient concentration in root tissue. Most morphological root traits responded to the single addition of K and the paired addition of N and P, with the greatest response to all three nutrients combined. The addition of N, P, and K together reduced fine-root biomass, length, and tissue density, and increased specific root length, whereas root diameter remained unchanged. Nitrogen addition did not alter root N concentration, but P and K addition increased root P and K concentration, respectively. Mycorrhizal colonization of fine roots declined with N, increased with P, and was unresponsive to K addition. Although plant species composition remains unchanged after 14 years of fertilization, fine-root characteristics responded to N, P, and K addition, providing some of the strongest stand-level responses in this experiment. Multiple soil nutrients regulate fine-root abundance, morphological and chemical traits, and their association

  17. Interaction effects of ambient UV radiation and nutrient limitation on the toxic cyanobacterium Nodularia spumigena.

    Science.gov (United States)

    Mohlin, Malin; Wulff, Angela

    2009-05-01

    Nodularia spumigena is one of the dominating species during the extensive cyanobacterial blooms in the Baltic Sea. The blooms coincide with strong light, stable stratification, low ratios of dissolved inorganic nitrogen, and dissolved inorganic phosphorus. The ability of nitrogen fixation, a high tolerance to phosphorus starvation, and different photo-protective strategies (production of mycosporine-like amino acids, MAAs) may give N. spumigena a competitive advantage over other phytoplankton during the blooms. To elucidate the interactive effects of ambient UV radiation and nutrient limitation on the performance of N. spumigena, an outdoor experiment was designed. Two radiation treatments photosynthetic active radiation (PAR) and PAR +UV-A + UV-B (PAB) and three nutrient treatments were established: nutrient replete (NP), nitrogen limited (-N), and phosphorus limited (-P). Variables measured were specific growth rate, heterocyst frequency, cell volume, cell concentrations of MAAs, photosynthetic pigments, particulate carbon (POC), particulate nitrogen (PON), and particulate phosphorus (POP). Ratios of particulate organic matter were calculated: POC/PON, POC/POP, and PON/POP. There was no interactive effect between radiation and nutrient limitation on the specific growth rate of N. spumigena, but there was an overall effect of phosphorus limitation on the variables measured. Interaction effects were observed for some variables; cell size (larger cells in -P PAB compared to other treatments) and the carotenoid canthaxanthin (highest concentration in -N PAR). In addition, significantly less POC and PON (mol cell(-1)) were found in -P PAR compared to -P PAB, and the opposite radiation effect was observed in -N. Our study shows that despite interactive effects on some of the variables studied, N. spumigena tolerate high ambient UVR also under nutrient limiting conditions and maintain positive growth rate even under severe phosphorus limitation.

  18. Effects of Nutrient Limitation on Pigments in Thalassiosira weissflogii and Prorocentrum donghaiense

    Institute of Scientific and Technical Information of China (English)

    Jian-Jun Hou; Bang-Qin Huang; Zhen-Rui Cao; Ji-Xin Chen; Hua-Sheng Hong

    2007-01-01

    The response of Prorocentrum donghaiense and Thalassiosira weissflogii pigments under nitrate (N) and phosphate (P) limitation were studied using HPLC and in vlvo fluorescence protocols in batch cultures. For P. donghalense,the pigment ratio was kept stable under different nutrient conditions from the results of HPLC. For T. weissflogii,there was a lower ratio of chlorophyllide to Chi a during the exponential phase, but the reverse during the stationary phase. Different members of the phytoplankton had different pigments response mechanisms under nutrient limitation. From the results of in vivo fluorescence, the ratio of peridinin to Chl a for P. donghaiense increased in nutrient-free culture, while it was kept stable for nutrient-limited cultures during the exponential phase. For T.weissflogii, the ratio of fucoxanthin to Chl a for each culture increased during the exponential phase, but the ratio under N limitation was apparently lower than that for P limitation during the stationary phase. The results indicate that both pigment ratios from HPLC and In vivo fluorescence of T. weissflogii were changed greatly under different nutrient conditions, which suggests that both ratios could be used as indicators of algal physiological status in different nutrient conditions.

  19. Lake and watershed characteristics rather than climate influence nutrient limitation in shallow lakes.

    Science.gov (United States)

    Kosten, Sarian; Huszar, Vera L M; Mazzeo, Néstor; Scheffer, Marten; Sternberg, Leonel da S L; Jeppesen, Erik

    2009-10-01

    Both nitrogen (N) and phosphorus (P) can limit primary production in shallow lakes, but it is still debated how the importance of N and P varies in time and space. We sampled 83 shallow lakes along a latitudinal gradient (5 degrees 55 degrees S) in South America and assessed the potential nutrient limitation using different methods including nutrient ratios in sediment, water, and seston, dissolved nutrient concentrations, and occurrence of N-fixing cyanobacteria. We found that local characteristics such as soil type and associated land use in the catchment, hydrology, and also the presence of abundant submerged macrophyte growth influenced N and P limitation. We found neither a consistent variation in nutrient limitation nor indications for a steady change in denitrification along the latitudinal gradient. Contrary to findings in other regions, we did not find a relationship between the occurrence of (N-fixing and non-N-fixing) cyanobacteria and the TN:TP ratio. We found N-fixing cyanobacteria (those with heterocysts) exclusively in lakes with dissolved inorganic nitrogen (DIN) concentrations of < 100 microg/L, but notably they were also often absent in lakes with low DIN concentrations. We argue that local factors such as land use and hydrology have a stronger influence on which nutrient is limiting than climate. Furthermore, our data show that in a wide range of climates N limitation does not necessarily lead to cyanobacterial dominance.

  20. [Population control and environment protection].

    Science.gov (United States)

    Qu, G

    1982-01-29

    Although many factors cause environmental pollution and damage, the most important and basic factor is a rapidly increasing population. Therefore, a balanced development of population and environment is essential. The pressure a rapidly increasing populaton exerts on the environment has many aspects. The pressure of population on land resources results in increased land use and increased insecticide use due to increased insect tolerance leading to decreased productivity of cultivated land, increased desert formation, and decreased food supply. Population pressure on forest resources leads to land erosion; one of the major causes of the 1981 flood in Sichuan was attributed to excessive logging activities. Demand for fuels (firewood, straws, animal manures) by an increasing population leads to decrease in natural fertilizers, decreased food production, and energy shortage in rural areas. Population pressure on cities leads to air, water, noise and other environmental pollution as well as decrease in housing facilities and in green vegetation. Problems resulting from population pressures on industrial development include industrial and environmental pollution and unemployment. Population increases and accompanying industrial activities affect the weather which in turn affects the quality of agriculture, forests, and lakes. Thus, if unchecked, atmospheric carbon dioxide level would double by the middle of the next century, which would lead to increase in atmospheric temperature with disastrous consequences. Therefore, a well planned program for population control is essential for achieving decent quality of life.

  1. Assessment of Nutrient Limitation in Floodplain Forests with Two Different Techniques

    Directory of Open Access Journals (Sweden)

    Matthew A. Neatrour

    2008-01-01

    Full Text Available We assessed nitrogen and phosphorus limitation in a floodplain forest in southern Georgia in USA using two commonly used methods: nitrogen to phosphorus (N:P ratios in litterfall and fertilized ingrowth cores. We measured nitrogen (N and phosphorus (P concentrations in litterfall to determine N:P mass ratios. We also installed ingrowth cores within each site containing native soil amended with nitrogen (N, phosphorus (P, or nitrogen and phosphorus (N + P fertilizers or without added fertilizer (C. Litter N:P ratios ranged from 16 to 22, suggesting P limitation. However, fertilized ingrowth cores indicated N limitation because fine-root length density was greater in cores fertilized with N or N + P than in those fertilized with P or without added fertilizer. We feel that these two methods of assessing nutrient limitation should be corroborated with fertilization trials prior to use on a wider basis.

  2. Shifts in lake N: P stoichiometry and nutrient limitation driven by atmospheric nitrogen deposition

    Science.gov (United States)

    Elser, J.J.; Andersen, T.; Baron, J.S.; Bergstrom, A.-K.; Jansson, M.; Kyle, M.; Nydick, K.R.; Steger, L.; Hessen, D.O.

    2009-01-01

    Human activities have more than doubled the amount of nitrogen (N) circulating in the biosphere. One major pathway of this anthropogenic N input into ecosystems has been increased regional deposition from the atmosphere. Here we show that atmospheric N deposition increased the stoichiometric ratio of N and phosphorus (P) in lakes in Norway, Sweden, and Colorado, United States, and, as a result, patterns of ecological nutrient limitation were shifted. Under low N deposition, phytoplankton growth is generally N-limited; however, in high-N deposition lakes, phytoplankton growth is consistently P-limited. Continued anthropogenic amplification of the global N cycle will further alter ecological processes, such as biogeochemical cycling, trophic dynamics, and biological diversity, in the world's lakes, even in lakes far from direct human disturbance.

  3. Experimental evaluation of nutrient limitation of phytoplankton communities in the Gulf of Riga

    Science.gov (United States)

    Seppälä, J.; Tamminen, T.; Kaitala, S.

    1999-12-01

    Phytoplankton nutrient limitation was studied in the Gulf of Riga during spring bloom (April 1995), early summer stage (June 1994), cyanobacterial bloom (July 1994) and post cyanobacterial bloom (August 1993). Each year six factorial nutrient enrichment experiments were carried out in various locations in the Gulf; including outer Irbe Strait, northern Gulf and southern Gulf. The responses of natural phytoplankton communities to the nutrient additions (80 μg NH 4-N l -1, 20 μg PO 4-P l -1 and two levels of combined additions) were followed for 3 days using 6 l experimental units. To evaluate the nutrient limitation patterns, time series of chlorophyll a were analysed using polynomial regression models and ranking method, taking advantage of the relatively constant experimental error. Apparent nutrient depletion rates and ratios were estimated, and compared with the changes in particulate nutrient ratios. During the spring diatom bloom in 1995, ambient inorganic nutrient concentrations were still high, and thus phytoplankton biomass did not respond to additions of nutrients. Chlorophyll a specific nutrient depletion rates were low (0.01-0.12 μg N (μg chl a) -1 h -1 and 0.002-0.016 μg P (μg chl a) -1 h -1) and linear over time, thus also revealing that phytoplankton was not limited by these nutrients in that time. In June 1994, there was an areal shift from N limitation in the outer Irbe Strait towards co-limitation in the southern Gulf. Later in July 1994, during the bloom of N-fixing Aphanizomenon flos-aquae, the N limitation was obvious for the whole study area. For this period chlorophyll a specific nutrient depletion rates were high (0.36-0.67 μg N (μg chl a) -1 h -1 and 0.089-0.135 μg P (μg chl a) -1 h -1), and added nutrients were almost totally depleted during the first light period. After the collapse of cyanobacterial bloom in August 1993, the experiment carried out in the southern Gulf indicated P limitation of phytoplankton. The central Gulf was

  4. Nutrient limitation restricts growth and reproductive output in a tropical montane cloud forest bromeliad: findings from a long-term forest fertilization experiment.

    Science.gov (United States)

    Lasso, Eloisa; Ackerman, James D

    2013-01-01

    From studies in seasonal lowland tropical forests, bromeliad epiphytes appear to be limited mainly by water, and to a lesser extent by nutrient supply, especially phosphorous. Less is understood about the mineral nutrition of tropical montane cloud forest (TMCF) epiphytes, even though their highest diversity is in this habitat. Nutrient limitation is known to be a key factor restricting forest productivity in TMCF, and if epiphytes are nutritionally linked to their host trees, as has been suggested, we would expect that they are also nutrient limited. We studied the effect of a higher nutrient input on reproduction and growth of the tank bromeliad Werauhia sintenisii in experimental plots located in a TMCF in Puerto Rico, where all macro- and micronutrients had been added quarterly starting in 1989 and continuing throughout the duration of this study. We found that bromeliads growing in fertilized plots were receiving litterfall with higher concentrations of N, P, and Zn and had higher concentrations of P, Zn, Fe, Al, and Na in their vegetative body. The N:P ratios found (fertilized = 27.5 and non-fertilized = 33.8) suggest that W. sintenisii may also be phosphorous limited as are lowland epiphytes. Fertilized plants had slightly longer inflorescences, and more flowers per inflorescence, than non-fertilized plants, but their flowers produced nectar in similar concentrations and quantities. Fertilized plants produced more seeds per fruit and per plant. Frequency of flowering in two consecutive years was higher for fertilized plants than for controls, suggesting that fertilized plants overcome the cost of reproduction more readily than non-fertilized plants. These results provide evidence that TMCF epiphytic bromeliads are nutrient limited like their lowland counterparts.

  5. Flexible access control for dynamic collaborative environments

    NARCIS (Netherlands)

    Dekker, Mari Antonius Cornelis

    2009-01-01

    Access control is used in computer systems to control access to confidential data. In this thesis we focus on access control for dynamic collaborative environments where multiple users and systems access and exchange data in an ad hoc manner. In such environments it is difficult to protect confident

  6. Asthma control: Patient and environment

    NARCIS (Netherlands)

    Rijssenbeek-Nouwens, L.H.M.

    2015-01-01

    Control of asthma, the goal of asthma treatment, seems hard to obtain. However, it is largely unknown why control of asthma remains difficult in many patients in spite of available powerful medication. In this thesis we studied non-pharmacological factors influencing asthma control: patient related

  7. Morphological and physiological adjustment to N and P fertilization in nutrient-limited Metrosideros polymorpha canopy trees in Hawaii.

    Science.gov (United States)

    Cordell, S; Goldstein, G; Meinzer, F C; Vitousek, P M

    2001-01-01

    Leaf-level studies of Metrosideros polymorpha Gaud. (Myrtaceae) canopy trees at both ends of a substrate age gradient in the Hawaiian Islands pointed to differential patterns of adjustment to both nutrient limitation and removal of this limitation by long-term (8-14 years) nitrogen (N), phosphorus (P) and N + P fertilizations. The two study sites were located at the same elevation, had similar annual precipitation, and supported forests dominated by M. polymorpha, but differed in the age of the underlying volcanic substrate, and in soil nutrient availability, with relatively low N at the young site (300 years, Thurston, Hawaii) and relatively low P at the oldest site (4,100,000 years, Kokee, Kauai). Within each site, responses to N and P fertilization were similar, regardless of the difference in soil N and P availability between sites. At the young substrate site, nutrient addition led to a larger mean leaf size (about 7.4 versus 4.8 cm2), resulting in a larger canopy leaf surface area. Differences in foliar N and P content, chlorophyll concentrations and carboxylation capacity between the fertilized and control plots were small. At the old substrate site, nutrient addition led to an increase in photosynthetic rate per unit leaf surface area from 4.5 to 7.6 micromol m(-2) s(-1), without a concomitant change in leaf size. At this site, leaves had substantially greater nutrient concentrations, chlorophyll content and carboxylation capacity in the fertilized plots than in the control plots. These contrasting acclimation responses to fertilization at the young and old sites led to significant increases in total carbon gain of M. polymorpha canopy trees at both sites. At the young substrate site, acclimation to fertilization was morphological, resulting in larger leaves, whereas at the old substrate site, physiological acclimation resulted in higher leaf carboxylation capacity and chlorophyll content.

  8. Assessment of changes in potential nutrient limitation in an impounded river after application of lanthanum-modified bentonite

    NARCIS (Netherlands)

    Douglas, Grant B.; Lurling, Miguel; Spears, Bryan M.

    2016-01-01

    With the advent of phosphorus (P)-adsorbent materials and techniques to address eutrophication in aquatic systems, there is a need to develop interpretive techniques to rapidly assess changes in potential nutrient limitation. In a trial application of the P-adsorbent, lanthanum-modified bentonite

  9. Adaptation of Bacillus subtilis carbon core metabolism to simultaneous nutrient limitation and osmotic challenge : a multi-omics perspective

    NARCIS (Netherlands)

    Kohlstedt, Michael; Sappa, Praveen K; Meyer, Hanna; Maaß, Sandra; Zaprasis, Adrienne; Hoffmann, Tamara; Becker, Judith; Steil, Leif; Hecker, Michael; van Dijl, Jan Maarten; Lalk, Michael; Mäder, Ulrike; Stülke, Jörg; Bremer, Erhard; Völker, Uwe; Wittmann, Christoph

    2014-01-01

    The Gram-positive bacterium Bacillus subtilis encounters nutrient limitations and osmotic stress in its natural soil ecosystem. To ensure survival and sustain growth, highly integrated adaptive responses are required. Here, we investigated the system-wide response of B.subtilis to different, simulta

  10. Assessment of changes in potential nutrient limitation in an impounded river after application of lanthanum-modified bentonite

    NARCIS (Netherlands)

    Douglas, Grant B.; Lurling, Miguel; Spears, Bryan M.

    2016-01-01

    With the advent of phosphorus (P)-adsorbent materials and techniques to address eutrophication in aquatic systems, there is a need to develop interpretive techniques to rapidly assess changes in potential nutrient limitation. In a trial application of the P-adsorbent, lanthanum-modified bentonite

  11. Global comparison reveals biogenic weathering as driven by nutrient limitation at ecosystem scale

    Science.gov (United States)

    Boy, Jens; Godoy, Roberto; Dechene, Annika; Shibistova, Olga; Amir, Hamid; Iskandar, Issi; Fogliano, Bruno; Boy, Diana; McCulloch, Robert; Andrino, Alberto; Gschwendtner, Silvia; Marin, Cesar; Sauheitl, Leopold; Dultz, Stefan; Mikutta, Robert; Guggenberger, Georg

    2017-04-01

    A substantial contribution of biogenic weathering in ecosystem nutrition, especially by symbiotic microorganisms, has often been proposed, but large-scale in vivo studies are still missing. Here we compare a set of ecosystems spanning from the Antarctic to tropical forests for their potential biogenic weathering and its drivers. To address biogenic weathering rates, we installed mineral mesocosms only accessible for bacteria and fungi for up to 4 years, which contained freshly broken and defined nutrient-baring minerals in soil A horizons of ecosystems along a gradient of soil development differing in climate and plant species communities. Alterations of the buried minerals were analyzed by grid-intersection, confocal lascer scanning microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy on the surface and on thin sections. On selected sites, carbon fluxes were tracked by 13C labeling, and microbial community was identified by DNA sequencing. In young ecosystems (protosoils) biogenic weathering is almost absent and starts after first carbon accumulation by aeolian (later litter) inputs and is mainly performed by bacteria. With ongoing soil development and appearance of symbiotic (mycorrhized) plants, nutrient availability in soil increasingly drove biogenic weathering, and fungi became the far more important players than bacteria. We found a close relation between fungal biogenic weathering and available potassium across all 16 forested sites in the study, regardless of the dominant mycorrhiza type (AM or EM), climate, and plant-species composition. We conclude that nutrient limitations at ecosystem scale are generally counteracted by adapted fungal biogenic weathering. The close relation between fungal weathering and plant-available nutrients over a large range of severely contrasting ecosystems points towards a direct energetic support of these weathering processes by the photoautotrophic community, making biogenic weathering a

  12. Nutrient limitation of native and invasive N2-fixing plants in northwest prairies

    Science.gov (United States)

    Thorpe, Andrea S.; Perakis, Steven S.; Catricala, Christina; Kaye, Thomas N.

    2013-01-01

    Nutrient rich conditions often promote plant invasions, yet additions of non-nitrogen (N) nutrients may provide a novel approach for conserving native symbiotic N-fixing plants in otherwise N-limited ecosystems. Lupinus oreganus is a threatened N-fixing plant endemic to prairies in western Oregon and southwest Washington (USA). We tested the effect of non-N fertilizers on the growth, reproduction, tissue N content, and stable isotope δ15N composition of Lupinus at three sites that differed in soil phosphorus (P) and N availability. We also examined changes in other Fabaceae (primarily Vicia sativa and V. hirsuta) and cover of all plant species. Variation in background soil P and N availability shaped patterns of nutrient limitation across sites. Where soil P and N were low, P additions increased Lupinus tissue N and altered foliar δ15N, suggesting P limitation of N fixation. Where soil P was low but N was high, P addition stimulated growth and reproduction in Lupinus. At a third site, with higher soil P, only micro- and macronutrient fertilization without N and P increased Lupinus growth and tissue N. Lupinus foliar δ15N averaged −0.010‰ across all treatments and varied little with tissue N, suggesting consistent use of fixed N. In contrast, foliar δ15N of Vicia spp. shifted towards 0‰ as tissue N increased, suggesting that conditions fostering N fixation may benefit these exotic species. Fertilization increased cover, N fixation, and tissue N of non-target, exotic Fabaceae, but overall plant community structure shifted at only one site, and only after the dominant Lupinus was excluded from analyses. Our finding that non-N fertilization increased the performance of Lupinus with few community effects suggests a potential strategy to aid populations of threatened legume species. The increase in exotic Fabaceae species that occurred with fertilization further suggests that monitoring and adaptive management should accompany any large scale applications.

  13. Nutrient limitation of native and invasive N2-fixing plants in northwest prairies.

    Directory of Open Access Journals (Sweden)

    Andrea S Thorpe

    Full Text Available Nutrient rich conditions often promote plant invasions, yet additions of non-nitrogen (N nutrients may provide a novel approach for conserving native symbiotic N-fixing plants in otherwise N-limited ecosystems. Lupinus oreganus is a threatened N-fixing plant endemic to prairies in western Oregon and southwest Washington (USA. We tested the effect of non-N fertilizers on the growth, reproduction, tissue N content, and stable isotope δ(15N composition of Lupinus at three sites that differed in soil phosphorus (P and N availability. We also examined changes in other Fabaceae (primarily Vicia sativa and V. hirsuta and cover of all plant species. Variation in background soil P and N availability shaped patterns of nutrient limitation across sites. Where soil P and N were low, P additions increased Lupinus tissue N and altered foliar δ(15N, suggesting P limitation of N fixation. Where soil P was low but N was high, P addition stimulated growth and reproduction in Lupinus. At a third site, with higher soil P, only micro- and macronutrient fertilization without N and P increased Lupinus growth and tissue N. Lupinus foliar δ(15N averaged -0.010‰ across all treatments and varied little with tissue N, suggesting consistent use of fixed N. In contrast, foliar δ(15N of Vicia spp. shifted towards 0‰ as tissue N increased, suggesting that conditions fostering N fixation may benefit these exotic species. Fertilization increased cover, N fixation, and tissue N of non-target, exotic Fabaceae, but overall plant community structure shifted at only one site, and only after the dominant Lupinus was excluded from analyses. Our finding that non-N fertilization increased the performance of Lupinus with few community effects suggests a potential strategy to aid populations of threatened legume species. The increase in exotic Fabaceae species that occurred with fertilization further suggests that monitoring and adaptive management should accompany any large scale

  14. Nutrient limitation of native and invasive N2-fixing plants in northwest prairies.

    Science.gov (United States)

    Thorpe, Andrea S; Perakis, Steven; Catricala, Christina; Kaye, Thomas N

    2013-01-01

    Nutrient rich conditions often promote plant invasions, yet additions of non-nitrogen (N) nutrients may provide a novel approach for conserving native symbiotic N-fixing plants in otherwise N-limited ecosystems. Lupinus oreganus is a threatened N-fixing plant endemic to prairies in western Oregon and southwest Washington (USA). We tested the effect of non-N fertilizers on the growth, reproduction, tissue N content, and stable isotope δ(15)N composition of Lupinus at three sites that differed in soil phosphorus (P) and N availability. We also examined changes in other Fabaceae (primarily Vicia sativa and V. hirsuta) and cover of all plant species. Variation in background soil P and N availability shaped patterns of nutrient limitation across sites. Where soil P and N were low, P additions increased Lupinus tissue N and altered foliar δ(15)N, suggesting P limitation of N fixation. Where soil P was low but N was high, P addition stimulated growth and reproduction in Lupinus. At a third site, with higher soil P, only micro- and macronutrient fertilization without N and P increased Lupinus growth and tissue N. Lupinus foliar δ(15)N averaged -0.010‰ across all treatments and varied little with tissue N, suggesting consistent use of fixed N. In contrast, foliar δ(15)N of Vicia spp. shifted towards 0‰ as tissue N increased, suggesting that conditions fostering N fixation may benefit these exotic species. Fertilization increased cover, N fixation, and tissue N of non-target, exotic Fabaceae, but overall plant community structure shifted at only one site, and only after the dominant Lupinus was excluded from analyses. Our finding that non-N fertilization increased the performance of Lupinus with few community effects suggests a potential strategy to aid populations of threatened legume species. The increase in exotic Fabaceae species that occurred with fertilization further suggests that monitoring and adaptive management should accompany any large scale applications.

  15. Can short-term and small-scale experiments reflect nutrient limitation on phytoplankton in natural lakes?

    Science.gov (United States)

    Wang, Haijun; Li, Yan; Feng, Weisong; Yu, Qing; Xiao, Xucheng; Liang, Xiaomin; Shao, Jianchun; Ma, Shuonan; Wang, Hongzhu

    2016-07-01

    Whether it is necessary to reduce nitrogen (N) and/or phosphorus (P) input to mitigate lake eutrophication is controversial. The controversy stems mainly from differences in time and space in previous studies that support the contrasting ideas. To test the response of phytoplankton to various combinations of nutrient control strategies in mesocosms and the possibility of reflecting the conditions in natural ecosystems with short-term experiments, a 9-month experiment was carried out in eight 800-L tanks with four nutrient level combinations (+N+P, -N+P, +N-P, and -N-P), with an 18-month whole-ecosystem experiment in eight ~800-m 2 ponds as the reference. Phytoplankton abundance was determined by P not N, regardless of the initial TN/TP level, which was in contrast to the nutrient limitation predicted by the N/P theory. Net natural N inputs were calculated to be 4.9, 6.8, 1.5, and 3.0 g in treatments +N+P, -N+P, +N-P, and -N-P, respectively, suggesting that N deficiency and P addition may promote natural N inputs to support phytoplankton development. However, the compensation process was slow, as suggested by an observed increase in TN after 3 weeks in -N+P and 2 months in -N-P in the tank experiment, and after 3 months in -N +P and ~3 months in -N-P in our pond experiment. Obviously, such a slow process cannot be simulated in short-term experiments. The natural N inputs cannot be explained by planktonic N-fixation because N-fixing cyanobacteria were scarce, which was probably because there was a limited pool of species in the tanks. Therefore, based on our results we argue that extrapolating short-term, small-scale experiments to large natural ecosystems does not give reliable, accurate results.

  16. Generation and Control of Game Virtual Environment

    Institute of Scientific and Technical Information of China (English)

    Myeong Won Lee; Jae Moon Lee

    2007-01-01

    In this paper, we present a framework for the generation and control of an Internet-based 3-dimensional game virtual environment that allows a character to navigate through the environment. Our framework includes 3-dimensional terrain mesh data processing, a map editor, scene processing, collision processing, and walkthrough control. We also define an environment-specific semantic information editor, which can be applied using specific location obtained from the real world. Users can insert text information related to the characters real position in the real world during navigation in the game virtual environment.

  17. Intelligent Mobile Robot Control in Unknown Environments

    Science.gov (United States)

    Mester, Gyula

    This paper gives the fuzzy reactive control of a wheeled mobile robot motion in an unknown environment with obstacles. The model of the vehicle has two driving wheels and the angular velocities of the two wheels are independently controlled. When the vehicle is moving towards the target and the sensors detect an obstacle, an avoiding strategy is necessary. We proposed a fuzzy reactive navigation strategy of collision-free motion in an unknown environment with obstacles. First, the vehicle kinematics constraints and kinematics model are analyzed. Then the fuzzy reactive control of a wheeled mobile robot motion in an unknown environment with obstacles is proposed. Output of the fuzzy controller is the angular speed difference between the left and right wheels (wheel angular speed correction) of the vehicle. The simulation results show the effectiveness and the validity of the obstacle avoidance behavior in an unknown environment of the proposed fuzzy control strategy.

  18. CONTROL ENVIRONMENT IN KOSOVO PUBLIC INSTITUTIONS

    Directory of Open Access Journals (Sweden)

    Shaqir M. REXHEPI

    2015-06-01

    Full Text Available The study on how is Internal Control System developed in public institutions is of a special importance for modalities, forms and the manner of the application of relevant strategies for the functioning of internal control environment in public institutions. In this paper, there is treated the existing situation of internal control system environment of public finances and its implementation in public sector. For internal control system environment in public finances to function effectively, there should exist a coherent control environment which includes responsibilities for financial management from managers of Publicly Owned Enterprises and with complete functioning of internal audit, which exists in the function of development to add value. In Kosovo public institutions, this framework is offered by legislation and by institutional mechanism for the implementation of legislation according to these parameters.

  19. Environment and health: Probes and sensors for environment digital control

    Science.gov (United States)

    Schettini, Chiara

    2014-05-01

    The idea of studying the environment using New Technologies (NT) came from a MIUR (Ministry of Education of the Italian Government) notice that allocated funds for the realization of innovative school science projects. The "Environment and Health" project uses probes and sensors for digital control of environment (water, air and soil). The working group was composed of 4 Science teachers from 'Liceo Statale G. Mazzini ', under the coordination of teacher Chiara Schettini. The Didactic Section of Naples City of Sciences helped the teachers in developing the project and it organized a refresher course for them on the utilization of digital control sensors. The project connects Environment and Technology because the study of the natural aspects and the analysis of the chemical-physical parameters give students and teachers skills for studying the environment based on the utilization of NT in computing data elaboration. During the practical project, samples of air, water and soil are gathered in different contexts. Sample analysis was done in the school's scientific laboratory with digitally controlled sensors. The data are elaborated with specific software and the results have been written in a booklet and in a computing database. During the first year, the project involved 6 school classes (age of the students 14—15 years), under the coordination of Science teachers. The project aims are: 1) making students more aware about environmental matters 2) achieving basic skills for evaluating air, water and soil quality. 3) achieving strong skills for the utilization of digitally controlled sensors. 4) achieving computing skills for elaborating and presenting data. The project aims to develop a large environmental conscience and the need of a ' good ' environment for defending our health. Moreover it would increase the importance of NT as an instrument of knowledge.

  20. Patterns in nutrient limitation and chlorophyll a along an anthropogenic eutrophication gradient in French Mediterranean coastal lagoons

    OpenAIRE

    Souchu, Philippe; Bec, Beatrice; Smith, Val H.; Laugier, Thierry; Fiandrino, Annie; Benau, Laurent; Orsoni, Valerie; Collos, Yves; Vaquer, Andre

    2010-01-01

    A cross-ecosystem comparison of data obtained from 20 French Mediterranean lagoons with contrasting eutrophication status provided the basis for investigating the variables that best predict chlorophyll a (Chl a) concentrations and nutrient limitation of phytoplankton biomass along a strong nutrient enrichment gradient. Summer concentrations of dissolved inorganic nitrogen (DIN) and phosphorus (DIP) comprised only a small fraction of total nitrogen (TN) and total phosphorus (TP). On the basis...

  1. Robot motion control in mobile environment

    Institute of Scientific and Technical Information of China (English)

    Iliya V Miroshnik; HUANG Xian-lin(黄显林); HE Jie(贺杰)

    2003-01-01

    With the problem of robot motion control in dynamic environment represented by mobile obstacles,working pieces and external mechanisms considered, a relevant control actions design procedure has been pro-posed to provide coordination of robot motions with respect to the moving external objects so that an extension ofrobot spatial motion techniques and active robotic strategies based on approaches of nonlinear control theory canbe achieved.

  2. Spatial and Temporal Patterns of Nutrient Limitation, Plant Biomass and Productivity, and Stream Metabolism Vary in Response to Short- and Long-Term Hydrological Regime Shifts

    Science.gov (United States)

    Grimm, N. B.; Sabo, J. L.; Dong, X.; Ruhí, A.

    2014-12-01

    Climate and hydrology are strong drivers of ecosystem structure and function in arid landscapes. Arid regions are characterized by high interannual variation in precipitation, and these climate patterns drive the overall hydrologic disturbance regime (in terms of flooding and drying), which influences geomorphic structure, biotic distributions, and nutrient status of desert stream ecosystems. We analyzed the long-term pattern of discharge in a desert stream in Arizona to identify hydrologic regime shifts, i.e., abrupt transitions between sequences of floods and droughts at periods of months to decades. We used wavelet analysis to identify time intervals over a 50-year time series that were negatively correlated with one another, reflecting a shift from wet to dry phases. We also looked with finer resolution at the most recent 10-year period, when wetlands have come to dominate the ecosystem owing to a management change, and at individual flood and drought events within years. In space, there is high site fidelity of wetland plant cover, corresponding to reliable water sources. Comparing five-year patterns of plant distribution and stream metabolism between wet and dry years suggested the primacy of geomorphic controls in drought periods. Nutrient limitation of algal production varied from moderate to very strong N limitation, with only one year when there was a (weak) suggestion of secondary P limitation. Over the longer period of record, we identified times characterized by hydrological regime shifts and asked whether ecosystem variables would have changed over that time period. We hypothesized, in particular, that the changes in nutrient status of the stream ecosystem would result from these regime shifts. We used our most complete long-term dataset on stream nitrogen (N) and phosphorus (P) concentrations and N:P ratios as a proxy for nutrient limitation. However, N:P varied primarily at fine scales in response to individual flood events.

  3. Employee quality, monitoring environment and internal control

    Directory of Open Access Journals (Sweden)

    Chunli Liu

    2017-03-01

    Full Text Available We investigate the effect of internal control employees (ICEs on internal control quality. Using special survey data from Chinese listed firms, we find that ICE quality has a significant positive influence on internal control quality. We examine the effect of monitoring on this result and find that the effect is more pronounced for firms with strict monitoring environments, especially when the firms implement the Chinese internal control regulation system (CSOX, have higher institutional ownership or attach greater importance to internal control. Our findings suggest that ICEs play an important role in the design and implementation of internal control systems. Our study should be of interest to both top managers who wish to improve corporate internal control quality and regulators who wish to understand the mechanisms of internal control monitoring.

  4. Do foliar, litter, and root nitrogen and phosphorus concentrations reflect nutrient limitation in a lowland tropical wet forest?

    Directory of Open Access Journals (Sweden)

    Silvia Alvarez-Clare

    Full Text Available Understanding nutrient limitation of net primary productivity (NPP is critical to predict how plant communities will respond to environmental change. Foliar nutrients, especially nitrogen and phosphorus concentrations ([N] and [P] and their ratio, have been used widely as indicators of plant nutritional status and have been linked directly to nutrient limitation of NPP. In tropical systems, however, a high number of confounding factors can limit the ability to predict nutrient limitation--as defined mechanistically by NPP responses to fertilization--based on the stoichiometric signal of the plant community. We used a long-term full factorial N and P fertilization experiment in a lowland tropical wet forest in Costa Rica to explore how tissue (foliar, litter and root [N] and [P] changed with fertilization, how different tree size classes and taxa influenced the community response, and how tissue nutrients related to NPP. Consistent with NPP responses to fertilization, there were no changes in community-wide foliar [N] and [P], two years after fertilization. Nevertheless, litterfall [N] increased with N additions and root [P] increased with P additions. The most common tree species (Pentaclethra macroloba had 9% higher mean foliar [N] with NP additions and the most common palm species (Socratea exohrriza had 15% and 19% higher mean foliar [P] with P and NP additions, respectively. Moreover, N:P ratios were not indicative of NPP responses to fertilization, either at the community or at the taxa level. Our study suggests that in these diverse tropical forests, tissue [N] and [P] are driven by the interaction of multiple factors and are not always indicative of the nutritional status of the plant community.

  5. Do foliar, litter, and root nitrogen and phosphorus concentrations reflect nutrient limitation in a lowland tropical wet forest?

    Science.gov (United States)

    Alvarez-Clare, Silvia; Mack, Michelle C

    2015-01-01

    Understanding nutrient limitation of net primary productivity (NPP) is critical to predict how plant communities will respond to environmental change. Foliar nutrients, especially nitrogen and phosphorus concentrations ([N] and [P]) and their ratio, have been used widely as indicators of plant nutritional status and have been linked directly to nutrient limitation of NPP. In tropical systems, however, a high number of confounding factors can limit the ability to predict nutrient limitation--as defined mechanistically by NPP responses to fertilization--based on the stoichiometric signal of the plant community. We used a long-term full factorial N and P fertilization experiment in a lowland tropical wet forest in Costa Rica to explore how tissue (foliar, litter and root) [N] and [P] changed with fertilization, how different tree size classes and taxa influenced the community response, and how tissue nutrients related to NPP. Consistent with NPP responses to fertilization, there were no changes in community-wide foliar [N] and [P], two years after fertilization. Nevertheless, litterfall [N] increased with N additions and root [P] increased with P additions. The most common tree species (Pentaclethra macroloba) had 9% higher mean foliar [N] with NP additions and the most common palm species (Socratea exohrriza) had 15% and 19% higher mean foliar [P] with P and NP additions, respectively. Moreover, N:P ratios were not indicative of NPP responses to fertilization, either at the community or at the taxa level. Our study suggests that in these diverse tropical forests, tissue [N] and [P] are driven by the interaction of multiple factors and are not always indicative of the nutritional status of the plant community.

  6. Are patterns in nutrient limitation belowground consistent with those aboveground: Results from a 4 million year chronosequence

    Science.gov (United States)

    Reed, S.C.; Vitousek, P.M.; Cleveland, C.C.

    2011-01-01

    Accurately predicting the effects of global change on net carbon (C) exchange between terrestrial ecosystems and the atmosphere requires a more complete understanding of how nutrient availability regulates both plant growth and heterotrophic soil respiration. Models of soil development suggest that the nature of nutrient limitation changes over the course of ecosystem development, transitioning from nitrogen (N) limitation in 'young' sites to phosphorus (P) limitation in 'old' sites. However, previous research has focused primarily on plant responses to added nutrients, and the applicability of nutrient limitation-soil development models to belowground processes has not been thoroughly investigated. Here, we assessed the effects of nutrients on soil C cycling in three different forests that occupy a 4 million year substrate age chronosequence where tree growth is N limited at the youngest site, co-limited by N and P at the intermediate-aged site, and P limited at the oldest site. Our goal was to use short-term laboratory soil C manipulations (using 14C-labeled substrates) and longer-term intact soil core incubations to compare belowground responses to fertilization with aboveground patterns. When nutrients were applied with labile C (sucrose), patterns of microbial nutrient limitation were similar to plant patterns: microbial activity was limited more by N than by P in the young site, and P was more limiting than N in the old site. However, in the absence of C additions, increased respiration of native soil organic matter only occurred with simultaneous additions of N and P. Taken together, these data suggest that altered nutrient inputs into ecosystems could have dissimilar effects on C cycling above- and belowground, that nutrients may differentially affect of the fate of different soil C pools, and that future changes to the net C balance of terrestrial ecosystems will be partially regulated by soil nutrient status. ?? 2010 US Government.

  7. Visual operations control in administrative environments

    Energy Technology Data Exchange (ETDEWEB)

    Carson, M.L.; Levine, L.O.

    1995-03-01

    When asked what comes to mind when they think of ``controlling work`` in the office, people may respond with ``overbearing boss,`` ``no autonomy,`` or ``Theory X management.`` The idea of controlling work in white collar or administrative environments can have a negative connotation. However, office life is often chaotic and miserable precisely because the work processes are out of control, and managers must spend their time looking over people`s shoulders and fighting fires. While management styles and structures vary, the need for control of work processes does not. Workers in many environments are being reorganized into self-managed work teams. These teams are expected to manage their own work through increased autonomy and empowerment. However, even empowered work teams must manage their work processes because of process variation. The amount of incoming jobs vary with both expected (seasonal) and unexpected demand. The mixture of job types vary over time, changing the need for certain skills or knowledge. And illness and turnover affect the availability of workers with needed skills and knowledge. Clearly, there is still a need to control work, whether the authority for controlling work is vested in one person or many. Visual control concepts provide simple, inexpensive, and flexible mechanisms for managing processes in work teams and continuous improvement administrative environments.

  8. Hierarchical Robot Control In A Multisensor Environment

    Science.gov (United States)

    Bhanu, Bir; Thune, Nils; Lee, Jih Kun; Thune, Mari

    1987-03-01

    Automatic recognition, inspection, manipulation and assembly of objects will be a common denominator in most of tomorrow's highly automated factories. These tasks will be handled by intelligent computer controlled robots with multisensor capabilities which contribute to desired flexibility and adaptability. The control of a robot in such a multisensor environment becomes of crucial importance as the complexity of the problem grows exponentially with the number of sensors, tasks, commands and objects. In this paper we present an approach which uses CAD (Computer-Aided Design) based geometric and functional models of objects together with action oriented neuroschemas to recognize and manipulate objects by a robot in a multisensor environment. The hierarchical robot control system is being implemented on a BBN Butterfly multi processor. Index terms: CAD, Hierarchical Control, Hypothesis Generation and Verification, Parallel Processing, Schemas

  9. Physiological Disorders in Closed, Controlled Environment Crops

    Science.gov (United States)

    Wheeler, Raymond M.; Morrow, Robert C.

    2010-01-01

    This slide presentation reviews some of the physiological disorders that affect crops grown in closed controlled environments. A physiological disorder is understood to be a problem resulting from the influence of environmental and horticultural factors on plan development other than a problem caused by a pathogen or some other abiotic cause. The topics that are addressed are: (1) Calcium-Related Disorders (2) Oedema (Intumescence) (3) Long-Photoperiod Injury (4) Light Spectral Quality Effects (5) Super-Elevated CO2 Injuries (6) Ethylene (7) Other Disorders (8) Considerations for Closed Space Environments. Views of plant with the disorders are shown.

  10. Inducer bacteria, unique signal peptides and nutrient limitation stimulate in-vitro bacteriocin production

    Science.gov (United States)

    Bacteriocins (BCN) provide enormous potential for controlling bacterial infections in human and veterinary medicine, in feedstuffs and human foods, and in cosmetic applications. To successfully apply such antimicrobial proteins, adequate commercial quantities of these valuable BCN must be efficient...

  11. Interactive formation control in complex environments.

    Science.gov (United States)

    Henry, Joseph; Shum, Hubert P H; Komura, Taku

    2014-02-01

    The degrees of freedom of a crowd is much higher than that provided by a standard user input device. Typically, crowd-control systems require multiple passes to design crowd movements by specifying waypoints, and then defining character trajectories and crowd formation. Such multi-pass control would spoil the responsiveness and excitement of real-time control systems. In this paper, we propose a single-pass algorithm to control a crowd in complex environments. We observe that low-level details in crowd movement are related to interactions between characters and the environment, such as diverging/merging at cross points, or climbing over obstacles. Therefore, we simplify the problem by representing the crowd with a deformable mesh, and allow the user, via multitouch input, to specify high-level movements and formations that are important for context delivery. To help prevent congestion, our system dynamically reassigns characters in the formation by employing a mass transport solver to minimize their overall movement. The solver uses a cost function to evaluate the impact from the environment, including obstacles and areas affecting movement speed. Experimental results show realistic crowd movement created with minimal high-level user inputs. Our algorithm is particularly useful for real-time applications including strategy games and interactive animation creation.

  12. Growth of Geobacter sulfurreducens under nutrient-limiting conditions in continuous culture.

    Science.gov (United States)

    Esteve-Núñez, Abraham; Rothermich, Mary; Sharma, Manju; Lovley, Derek

    2005-05-01

    A system for growing Geobacter sulfurreducens under anaerobic conditions in chemostats was developed in order to study the physiology of this organism under conditions that might more closely approximate those found in the subsurface than batch cultures. Geobacter sulfurreducens could be cultured under acetate-limiting conditions with fumarate or Fe(III)-citrate as the electron acceptor at growth rates between 0.04 and 0.09 h(-1). The molar growth yield was threefold higher with fumarate as the electron acceptor than with Fe(III), despite the lower mid-point potential of the fumarate/succinate redox couple. When growth was limited by availability of fumarate, high steady-state concentrations were detected, suggesting that fumarate is unlikely to be an important electron acceptor in sedimentary environments. The half-saturation constant, Ks, for acetate in Fe(III)-grown cultures (10 microM) suggested that the growth of Geobacter species is likely to be acetate limited in most subsurface sediments, but that when millimolar quantities of acetate are added to the subsurface in order to promote the growth of Geobacter for bioremediation applications, this should be enough to overcome any acetate limitations. When the availability of electron acceptors, rather than acetate, limited growth, G. sulfurreducens was less efficient in incorporating acetate into biomass but had higher respiration rates, a desirable physiological characteristic when adding acetate to stimulate the activity of Geobacter species during in situ uranium bioremediation. These results demonstrate that the ability to study the growth of G. sulfurreducens under steady-state conditions can provide insights into its physiological characteristics that have relevance for its activity in a diversity of sedimentary environments.

  13. Substrate and nutrient limitation of ammonia-oxidizing bacteria and archaea in temperate forest soil

    Science.gov (United States)

    J.S. Norman; J.E. Barrett

    2014-01-01

    Ammonia-oxidizing microbes control the rate-limiting step of nitrification, a critical ecosystem process, which affects retention and mobility of nitrogen in soil ecosystems. This study investigated substrate (NH4þ) and nutrient (K and P) limitation of ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) in temperate forest soils at Coweeta Hydrologic...

  14. Nutrient limitation and physiology mediate the fine-scale (de)coupling of biogeochemical cycles.

    Science.gov (United States)

    Appling, Alison P; Heffernan, James B

    2014-09-01

    Nutrients in the environment are coupled over broad timescales (days to seasons) when organisms add or withdraw multiple nutrients simultaneously and in ratios that are roughly constant. But at finer timescales (seconds to days), nutrients become decoupled if physiological traits such as nutrient storage limits, circadian rhythms, or enzyme kinetics cause one nutrient to be processed faster than another. To explore the interactions among these coupling and decoupling mechanisms, we introduce a model in which organisms process resources via uptake, excretion, growth, respiration, and mortality according to adjustable trait parameters. The model predicts that uptake can couple the input of one nutrient to the export of another in a ratio reflecting biological demand stoichiometry, but coupling occurs only when the input nutrient is limiting. Temporal nutrient coupling may, therefore, be a useful indicator of ecosystem limitation status. Fine-scale patterns of nutrient coupling are further modulated by, and potentially diagnostic of, physiological traits governing growth, uptake, and internal nutrient storage. Together, limitation status and physiological traits create a complex and informative relationship between nutrient inputs and exports. Understanding the mechanisms behind that relationship could enrich interpretations of fine-scale time-series data such as those now emerging from in situ solute sensors.

  15. Nutrient limitation of primary productivity in the Southeast Pacific (BIOSOPE cruise

    Directory of Open Access Journals (Sweden)

    S. Bonnet

    2008-02-01

    Full Text Available Iron is an essential nutrient involved in a variety of biological processes in the ocean, including photosynthesis, respiration and dinitrogen fixation. Atmospheric deposition of aerosols is recognized as the main source of iron for the surface ocean. In high nutrient, low chlorophyll areas, it is now clearly established that iron limits phytoplankton productivity but its biogeochemical role in low nutrient, low chlorophyll environments has been poorly studied. We investigated this question in the unexplored southeast Pacific, arguably the most oligotrophic area of the global ocean. Situated far from any continental aerosol source, the atmospheric iron flux to this province is amongst the lowest of the world ocean. Here we report that, despite low dissolved iron concentrations (~0.1 nmol l−1 across the whole gyre (3 stations located in the center and at the western and the eastern edges, primary productivity are only limited by iron availability at the border of the gyre, but not in the center. The seasonal stability of the gyre has apparently allowed for the development of populations acclimated to these extreme oligotrophic conditions. Moreover, despite clear evidence of nitrogen limitation in the central gyre, we were unable to measure dinitrogen fixation in our experiments, even after iron and/or phosphate additions, and cyanobacterial nif H gene abundances were extremely low compared to the North Pacific Gyre. The South Pacific gyre is therefore unique with respect to the physiological status of its phytoplankton populations.

  16. Elemental economy: microbial strategies for optimizing growth in the face of nutrient limitation.

    Science.gov (United States)

    Merchant, Sabeeha S; Helmann, John D

    2012-01-01

    Microorganisms play a dominant role in the biogeochemical cycling of nutrients. They are rightly praised for their facility for fixing both carbon and nitrogen into organic matter, and microbial driven processes have tangibly altered the chemical composition of the biosphere and its surrounding atmosphere. Despite their prodigious capacity for molecular transformations, microorganisms are powerless in the face of the immutability of the elements. Limitations for specific elements, either fleeting or persisting over eons, have left an indelible trace on microbial genomes, physiology, and their very atomic composition. We here review the impact of elemental limitation on microbes, with a focus on selected genetic model systems and representative microbes from the ocean ecosystem. Evolutionary adaptations that enhance growth in the face of persistent or recurrent elemental limitations are evident from genome and proteome analyses. These range from the extreme (such as dispensing with a requirement for a hard to obtain element) to the extremely subtle (changes in protein amino acid sequences that slightly, but significantly, reduce cellular carbon, nitrogen, or sulfur demand). One near-universal adaptation is the development of sophisticated acclimation programs by which cells adjust their chemical composition in response to a changing environment. When specific elements become limiting, acclimation typically begins with an increased commitment to acquisition and a concomitant mobilization of stored resources. If elemental limitation persists, the cell implements austerity measures including elemental sparing and elemental recycling. Insights into these fundamental cellular properties have emerged from studies at many different levels, including ecology, biological oceanography, biogeochemistry, molecular genetics, genomics, and microbial physiology. Here, we present a synthesis of these diverse studies and attempt to discern some overarching themes.

  17. Nutrients limit photosynthesis in seedlings of a lowland tropical forest tree species.

    Science.gov (United States)

    Pasquini, S C; Santiago, L S

    2012-02-01

    We investigated how photosynthesis by understory seedlings of the lowland tropical tree species Alseis blackiana responded to 10 years of soil nutrient fertilization with N, P and K. We ask whether nutrients are limiting to light and CO(2) acquisition in a low light understory environment. We measured foliar nutrient concentrations of N, P and K, isotopic composition of carbon (δ(13)C) and nitrogen (δ(15)N), and light response curves of photosynthesis and chlorophyll fluorescence. Canopy openness was measured above each study seedling and included in statistical analyses to account for variation in light availability. Foliar N concentration increased by 20% with N addition. Foliar P concentration increased by 78% with P addition and decreased by 14% with N addition. Foliar K increased by 8% with K addition. Foliar δ(13)C showed no significant responses, and foliar δ(15)N decreased strongly with N addition, matching the low δ(15)N values of applied fertilizer. Canopy openness ranged from 0.01 to 6.71% with a mean of 1.76 ± 0.14 (± 1SE). Maximum photosynthetic CO(2) assimilation rate increased by 9% with N addition. Stomatal conductance increased with P addition and with P and K in combination. Chlorophyll fluorescence measurements revealed that quantum yield of photosystem II increased with K addition, maximum electron transport rate trended 9% greater with N addition (p = 0.07), and saturating photosynthetically active radiation increased with N addition. The results demonstrate that nutrient addition can enhance photosynthetic processes, even under low light availability.

  18. Nutrient limitation governs Staphylococcus aureus metabolism and niche adaptation in the human nose.

    Directory of Open Access Journals (Sweden)

    Bernhard Krismer

    2014-01-01

    Full Text Available Colonization of the human nose by Staphylococcus aureus in one-third of the population represents a major risk factor for invasive infections. The basis for adaptation of S. aureus to this specific habitat and reasons for the human predisposition to become colonized have remained largely unknown. Human nasal secretions were analyzed by metabolomics and found to contain potential nutrients in rather low amounts. No significant differences were found between S. aureus carriers and non-carriers, indicating that carriage is not associated with individual differences in nutrient supply. A synthetic nasal medium (SNM3 was composed based on the metabolomics data that permits consistent growth of S. aureus isolates. Key genes were expressed in SNM3 in a similar way as in the human nose, indicating that SNM3 represents a suitable surrogate environment for in vitro simulation studies. While the majority of S. aureus strains grew well in SNM3, most of the tested coagulase-negative staphylococci (CoNS had major problems to multiply in SNM3 supporting the notion that CoNS are less well adapted to the nose and colonize preferentially the human skin. Global gene expression analysis revealed that, during growth in SNM3, S. aureus depends heavily on de novo synthesis of methionine. Accordingly, the methionine-biosynthesis enzyme cysteine-γ-synthase (MetI was indispensable for growth in SNM3, and the MetI inhibitor DL-propargylglycine inhibited S. aureus growth in SNM3 but not in the presence of methionine. Of note, metI was strongly up-regulated by S. aureus in human noses, and metI mutants were strongly abrogated in their capacity to colonize the noses of cotton rats. These findings indicate that the methionine biosynthetic pathway may include promising antimicrobial targets that have previously remained unrecognized. Hence, exploring the environmental conditions facultative pathogens are exposed to during colonization can be useful for understanding niche

  19. Wastewater contaminant transport and treatment in a nutrient limited ribbed fen

    Science.gov (United States)

    McCarter, C. P. R.; Price, J. S.; Branfireun, B. A.

    2015-12-01

    To minimize the discharge of wastewater contaminants from remote northern communities and mining operations, fen peatlands in sub-arctic regions are used for tertiary wastewater treatment to detain, transform, and remove these contaminants. However, there is a limited understanding of contaminant transport and treatment in fen peatlands, particularly in sub-arctic Canada. To better characterize wastewater contaminant transport and treatment in these systems, approximately 44 m3 day-1 of simulated wastewater, concentrated custom-blend fertilizer (NO3-, PO33-, and SO42-) and Cl- diluted with water, was pumped into a small 0.5 ha sub-arctic ribbed fen continuously for 47 days (July 15th -August 31st 2014). Contaminant concentration of 3 similar ribbed fens varied between 0.0-3.0 mg L-1 over the study period (May - September 2014). An exponential increase in transmissivity (2.4 to 16.8 m2 day-1) as the water table rose (~0.16 m) increased the average linear groundwater velocity (0.5 to 3.4 m day-1) and resulted in rapid SO42- (0.8 m day-1) and Cl- (1.9 m day-1) transport. Notwithstanding the rapid transport of Cl-, diffusion into inactive pores still retarded Cl- transport by a factor of 1.8. Contrary to the rapid transport of SO42- and Cl-, the other contaminants were rapidly removed from the pore water (likely through biological uptake or adsorption) and minimal transport was observed (0.29 and 0.04 m day-1 for PO33- and NO3-, respectively). Northern ribbed fens have a large capacity to detain certain wastewater contaminants (e.g., NO3- and PO33-), yet allow rapid transport of others (e.g., SO42- and Cl-). Thus, these peatlands have the potential to significantly decrease wastewater contamination in northern aquatic environment by both biogeochemical and physical processes but careful management of the hydrology is required to prevent the release of mobile contaminants.

  20. Biocorrosion and biofilm formation in a nutrient limited heating system subjected to alternating microaerophilic conditions.

    Science.gov (United States)

    Kjellerup, B V; Kjeldsen, K U; Lopes, F; Abildgaard, L; Ingvorsen, K; Frølund, B; Sowers, K R; Nielsen, P H

    2009-11-01

    Severe biofilm formation and biocorrosion have been observed in heating systems even when the water quality complied with existing standards. The coupling between water chemistry, biofilm formation, species composition, and biocorrosion in a heating system was investigated by adding low concentrations of nutrients and oxygen under continuous and alternating dosing regimes. Molecular analysis of 16S rRNA gene fragments demonstrated that the amendments did not cause changes in the overall bacterial community composition. The combined alternating dosing of nutrients and oxygen caused increased rates of pitting (bio-) corrosion. Detection of bacteria involved in sulfide production and oxidation by retrieval of the functional dsrAB and apsA genes revealed the presence of Gram-positive sulfate- and sulfite-reducers and an unknown sulfur-oxidizer. Therefore, to control biocorrosion, sources of oxygen and nutrients must be limited, since the effect of the alternating operational conditions apparently is more important than the presence of potentially corrosive biofilm bacteria.

  1. Nutrient Limitations Constrain the Feedback Capacity of Landscapes in the High Arctic: Nonlinearities and Synergism

    Science.gov (United States)

    Arens, S. J.; Sullivan, P. F.; Welker, J. M.; Rogers, M. C.; Holland, K.; Schimel, J.; Persson, K.

    2006-12-01

    Nutrient availability appears to be a controlling factor in the structure and function of High Arctic terrestrial systems as depicted by biological hot spots such as bird cliffs which are found throughout the arctic. Understanding the processes by which nutrients control plant production, canopy structure, and ecosystem carbon cycling have been well studied in the Low Arctic, where fertilization experiments have been employed for decades. Few studies have examined how the amount and type of nutrient augmentations (fertilization) affects the magnitude and pattern of CO2 exchange, species composition and optical properties of prostrate dwarf-shrub, herb tundra, the largest ecosystem in the High Arctic. In this study, amendments of three levels of nitrogen (N) (0.5 g/m2, 1.0 g/m2 and 5.0 g/m2) phosphorus (P) (2.5 g/m2) were initiated in prostrate dwarf- shrub, herb tundra near Pituffik (Thule), Greenland (76¢ªN, 68¢ªW). Species composition, net ecosystem CO2 exchange (NEE), gross primary photosynthesis (GPP), ecosystem respiration (ER) and plot-level normalized difference vegetation index (NDVI) were used to quantify changes in ecosystem structure and function. Non- linear responses to the addition of different levels of N were observed. CO2 gas exchange and NDVI showed indicated the strongest response at middle levels of N addition (1.0 g/m2). Strong and synergystic responses to the combined addition of nitrogen and phosphorus were observed. Increases in vegetation density and a shift in species composition were observed when N and P were added to these systems, partially explaining the near doubling of NDVI values from 0.3 to 0.6. Rates of NEE, GPP and ER were significantly higher when N and P were combined compared to independent additions of each or when compared to non-fertilized areas. Our results indicate that feedback processes such as CO2 exchange, optical properties and vegetation composition and structure are co-limited by N and P and that the addition

  2. Injuries to plants from controlled environment contaminants

    Science.gov (United States)

    Tibbitts, T. W.

    The use of controlled environments is subject to problems from contaminants emitted from materials of the system and from plants. Many contaminants are difficult to identify because injurious dosages are very low, there is a lack of information on what compounds injure plants, because species and cultivars differ greatly in their sensitivity to injury and injury symptoms often are not distinctive. Plastics have been shown to emit many different volatile compounds. The compound, di-butyl phthalate, contained in certain flexible plastics, has been shown to be very toxic to plants. Other injuries have been produced by caulking compounds and bonded screening. Paints have been shown to release xylene that is toxic to plants. Steam for humidification can cause problems because of hydroxylamines and other compounds added to steam used for heating to control fungal growth in return lines. Mercury, from broken thermometers is a particular problem in growth chambers because small quantities can collect in cracks and slowly volatilize to slow growth of plants. Plants themselves release large quantities of volatile hydrocarbons, with ethylene being the commonly recognized chemical that can be damaging when allowed to accumulate. People release large quantities of carbon dioxide which can cause variations in the rate of growth of plants. Contaminant problems can be controlled through filtering of the air or ventilation with make-up air, however the potential for problems is always present and careful testing should be undertaken with the particular species and cultivars being grown to insure that there are no toxic agents altering growth in each particular controlled environment being utilized.

  3. Nutrient limitation reduces land carbon uptake in simulations with a model of combined carbon, nitrogen and phosphorus cycling

    Directory of Open Access Journals (Sweden)

    D. S. Goll

    2012-09-01

    Full Text Available Terrestrial carbon (C cycle models applied for climate projections simulate a strong increase in net primary productivity (NPP due to elevated atmospheric CO2 concentration during the 21st century. These models usually neglect the limited availability of nitrogen (N and phosphorus (P, nutrients that commonly limit plant growth and soil carbon turnover. To investigate how the projected C sequestration is altered when stoichiometric constraints on C cycling are considered, we incorporated a P cycle into the land surface model JSBACH (Jena Scheme for Biosphere–Atmosphere Coupling in Hamburg, which already includes representations of coupled C and N cycles.

    The model reveals a distinct geographic pattern of P and N limitation. Under the SRES (Special Report on Emissions Scenarios A1B scenario, the accumulated land C uptake between 1860 and 2100 is 13% (particularly at high latitudes and 16% (particularly at low latitudes lower in simulations with N and P cycling, respectively, than in simulations without nutrient cycles. The combined effect of both nutrients reduces land C uptake by 25% compared to simulations without N or P cycling. Nutrient limitation in general may be biased by the model simplicity, but the ranking of limitations is robust against the parameterization and the inflexibility of stoichiometry. After 2100, increased temperature and high CO2 concentration cause a shift from N to P limitation at high latitudes, while nutrient limitation in the tropics declines. The increase in P limitation at high-latitudes is induced by a strong increase in NPP and the low P sorption capacity of soils, while a decline in tropical NPP due to high autotrophic respiration rates alleviates N and P limitations. The quantification of P limitation remains challenging. The poorly constrained processes of soil P sorption and biochemical mineralization are identified as the main uncertainties in the strength of P limitation

  4. Controlling social stress in virtual reality environments.

    Science.gov (United States)

    Hartanto, Dwi; Kampmann, Isabel L; Morina, Nexhmedin; Emmelkamp, Paul G M; Neerincx, Mark A; Brinkman, Willem-Paul

    2014-01-01

    Virtual reality exposure therapy has been proposed as a viable alternative in the treatment of anxiety disorders, including social anxiety disorder. Therapists could benefit from extensive control of anxiety eliciting stimuli during virtual exposure. Two stimuli controls are studied in this study: the social dialogue situation, and the dialogue feedback responses (negative or positive) between a human and a virtual character. In the first study, 16 participants were exposed in three virtual reality scenarios: a neutral virtual world, blind date scenario, and job interview scenario. Results showed a significant difference between the three virtual scenarios in the level of self-reported anxiety and heart rate. In the second study, 24 participants were exposed to a job interview scenario in a virtual environment where the ratio between negative and positive dialogue feedback responses of a virtual character was systematically varied on-the-fly. Results yielded that within a dialogue the more positive dialogue feedback resulted in less self-reported anxiety, lower heart rate, and longer answers, while more negative dialogue feedback of the virtual character resulted in the opposite. The correlations between on the one hand the dialogue stressor ratio and on the other hand the means of SUD score, heart rate and audio length in the eight dialogue conditions showed a strong relationship: r(6) = 0.91, p = 0.002; r(6) = 0.76, p = 0.028 and r(6) = -0.94, p = 0.001 respectively. Furthermore, more anticipatory anxiety reported before exposure was found to coincide with more self-reported anxiety, and shorter answers during the virtual exposure. These results demonstrate that social dialogues in a virtual environment can be effectively manipulated for therapeutic purposes.

  5. Controlling social stress in virtual reality environments.

    Directory of Open Access Journals (Sweden)

    Dwi Hartanto

    Full Text Available Virtual reality exposure therapy has been proposed as a viable alternative in the treatment of anxiety disorders, including social anxiety disorder. Therapists could benefit from extensive control of anxiety eliciting stimuli during virtual exposure. Two stimuli controls are studied in this study: the social dialogue situation, and the dialogue feedback responses (negative or positive between a human and a virtual character. In the first study, 16 participants were exposed in three virtual reality scenarios: a neutral virtual world, blind date scenario, and job interview scenario. Results showed a significant difference between the three virtual scenarios in the level of self-reported anxiety and heart rate. In the second study, 24 participants were exposed to a job interview scenario in a virtual environment where the ratio between negative and positive dialogue feedback responses of a virtual character was systematically varied on-the-fly. Results yielded that within a dialogue the more positive dialogue feedback resulted in less self-reported anxiety, lower heart rate, and longer answers, while more negative dialogue feedback of the virtual character resulted in the opposite. The correlations between on the one hand the dialogue stressor ratio and on the other hand the means of SUD score, heart rate and audio length in the eight dialogue conditions showed a strong relationship: r(6 = 0.91, p = 0.002; r(6 = 0.76, p = 0.028 and r(6 = -0.94, p = 0.001 respectively. Furthermore, more anticipatory anxiety reported before exposure was found to coincide with more self-reported anxiety, and shorter answers during the virtual exposure. These results demonstrate that social dialogues in a virtual environment can be effectively manipulated for therapeutic purposes.

  6. Controlling Social Stress in Virtual Reality Environments

    Science.gov (United States)

    Hartanto, Dwi; Kampmann, Isabel L.; Morina, Nexhmedin; Emmelkamp, Paul G. M.; Neerincx, Mark A.; Brinkman, Willem-Paul

    2014-01-01

    Virtual reality exposure therapy has been proposed as a viable alternative in the treatment of anxiety disorders, including social anxiety disorder. Therapists could benefit from extensive control of anxiety eliciting stimuli during virtual exposure. Two stimuli controls are studied in this study: the social dialogue situation, and the dialogue feedback responses (negative or positive) between a human and a virtual character. In the first study, 16 participants were exposed in three virtual reality scenarios: a neutral virtual world, blind date scenario, and job interview scenario. Results showed a significant difference between the three virtual scenarios in the level of self-reported anxiety and heart rate. In the second study, 24 participants were exposed to a job interview scenario in a virtual environment where the ratio between negative and positive dialogue feedback responses of a virtual character was systematically varied on-the-fly. Results yielded that within a dialogue the more positive dialogue feedback resulted in less self-reported anxiety, lower heart rate, and longer answers, while more negative dialogue feedback of the virtual character resulted in the opposite. The correlations between on the one hand the dialogue stressor ratio and on the other hand the means of SUD score, heart rate and audio length in the eight dialogue conditions showed a strong relationship: r(6) = 0.91, p = 0.002; r(6) = 0.76, p = 0.028 and r(6) = −0.94, p = 0.001 respectively. Furthermore, more anticipatory anxiety reported before exposure was found to coincide with more self-reported anxiety, and shorter answers during the virtual exposure. These results demonstrate that social dialogues in a virtual environment can be effectively manipulated for therapeutic purposes. PMID:24671006

  7. Access control mechanisms for distributed healthcare environments.

    Science.gov (United States)

    Sergl-Pommerening, Marita

    2004-01-01

    Today's IT-infrastructure provides more and more possibilities to share electronic patient data across several healthcare organizations and hospital departments. A strong requirement is sufficient data protection and security measures complying with the medical confidentiality and the data protection laws of each state or country like the European directive on data protection or the U.S. HIPAA privacy rule. In essence, the access control mechanisms and authorization structures of information systems must be able to realize the Need-To-Access principle. This principle can be understood as a set of context-sensitive access rules, regarding the patient's path across the organizations. The access control mechanisms of today's health information systems do not sufficiently satisfy this requirement, because information about participation of persons or organizations is not available within each system in a distributed environment. This problem could be solved by appropriate security services. The CORBA healthcare domain standard contains such a service for obtaining authorization decisions and administrating access decision policies (RAD). At the university hospital of Mainz we have developed an access control system (MACS), which includes the main functionality of the RAD specification and the access control logic that is needed for such a service. The basic design principles of our approach are role-based authorization, user rights with static and dynamic authorization data, context rules and the separation of three cooperating servers that provide up-to-date knowledge about users, roles and responsibilities. This paper introduces the design principles and the system design and critically evaluates the concepts based on practical experience.

  8. An operating environment for control systems on transputer networks

    NARCIS (Netherlands)

    Tillema, H.G.; Schoute, Albert L.; Wijbrans, K.C.J.; Wijbrans, K.C.J.

    1991-01-01

    The article describes an operating environment for control systems. The environment contains the basic layers of a distributed operating system. The design of this operating environment is based on the requirements demanded by controllers which can be found in complex control systems. Due to the

  9. Earth Rings for Planetary Environment Control

    Science.gov (United States)

    Pearson, Jerome; Oldson, John; Levin, Eugene; Carroll, Joseph

    2002-01-01

    For most of its past, large parts of the Earth have experienced subtropical climates, with high sea levels and no polar icecaps. This warmer environment was punctuated 570, 280, and 3 million years ago with periods of glaciation that covered temperate regions with thick ice for millions of years. At the end of the current ice age, a warmer climate could flood coastal cities, even without human-caused global warming. In addition, asteroids bombard the Earth periodically, with impacts large enough to destroy most life on Earth, and the sun is warming inexorably. This paper proposes a concept to solve these problems simultaneously, by creating an artificial planetary ring about the Earth to shade it. Past proposals for space climate control have depended on gigantic engineering structures launched from Earth and placed in Earth orbit or at the Earth-Sun L1 libration point, requiring fabrication, large launch masses and expense, constant control, and repair. Our solution is to begin by using lunar material, and then mine and remove Earth-orbit-crossing asteroids and discard the tailings into Earth orbit, to form a broad, flat ring like those of Saturn. This solution is evaluated and compared with other alternatives. Such ring systems can persist for thousands of years, and can be maintained by shepherding satellites or by continual replenishment from new asteroids to replace the edges of the ring lost by diffusion. An Earth ring at R = 1.3-1.83 RE would shade only the equatorial regions, moderating climate extremes, and could reverse a century of global warming. It could also absorb particles from the radiation belts, making trips to high Earth orbit and GEO safer for humans and for electronics. It would also light the night many times as bright as the full moon. A preliminary design of the ring is developed, including its location, mass, composition, stability, and timescale required. A one-dimensional climate model is used to evaluate the Earth ring performance

  10. Hyperosmosis and its combination with nutrient-limitation are novel environmental stressors for induction of triacylglycerol accumulation in cells of Chlorella kessleri.

    Science.gov (United States)

    Hirai, Kazuho; Hayashi, Taihei; Hasegawa, Yuri; Sato, Atsushi; Tsuzuki, Mikio; Sato, Norihiro

    2016-05-17

    Triacylglycerols of oleaginous algae are promising for production of food oils and biodiesel fuel. Air-drying of cells induces triacylglycerol accumulation in a freshwater green alga, Chlorella kessleri, therefore, it seems that dehydration, i.e., intracellular hyperosmosis, and/or nutrient-limitation are key stressors. We explored this possibility in liquid-culturing C. kessleri cells. Strong hyperosmosis with 0.9 M sorbitol or 0.45 M NaCl for two days caused cells to increase the triacylglycerol content in total lipids from 1.5 to 48.5 and 75.3 mol%, respectively, on a fatty acid basis, whereas nutrient-limitation caused its accumulation to 41.4 mol%. Even weak hyperosmosis with 0.3 M sorbitol or 0.15 M NaCl, when nutrient-limitation was simultaneously imposed, induced triacylglycerol accumulation to 61.9 and 65.7 mol%, respectively. Furthermore, culturing in three-fold diluted seawater, the chemical composition of which resembled that of the medium for the combinatory stress, enabled the cells to accumulate triacylglycerol up to 24.7 weight% of dry cells in only three days. Consequently, it was found that hyperosmosis is a novel stressor for triacylglycerol accumulation, and that weak hyperosmosis, together with nutrient-limitation, exerts a strong stimulating effect on triacylglycerol accumulation. A similar combinatory stress would contribute to the triacylglycerol accumulation in air-dried C. kessleri cells.

  11. Self versus environment motion in postural control.

    Directory of Open Access Journals (Sweden)

    Kalpana Dokka

    2010-02-01

    Full Text Available To stabilize our position in space we use visual information as well as non-visual physical motion cues. However, visual cues can be ambiguous: visually perceived motion may be caused by self-movement, movement of the environment, or both. The nervous system must combine the ambiguous visual cues with noisy physical motion cues to resolve this ambiguity and control our body posture. Here we have developed a Bayesian model that formalizes how the nervous system could solve this problem. In this model, the nervous system combines the sensory cues to estimate the movement of the body. We analytically demonstrate that, as long as visual stimulation is fast in comparison to the uncertainty in our perception of body movement, the optimal strategy is to weight visually perceived movement velocities proportional to a power law. We find that this model accounts for the nonlinear influence of experimentally induced visual motion on human postural behavior both in our data and in previously published results.

  12. Community structure and activity of a highly dynamic and nutrient-limited hypersaline microbial mat in Um Alhool Sabkha, Qatar.

    Directory of Open Access Journals (Sweden)

    Roda Al-Thani

    Full Text Available The Um Alhool area in Qatar is a dynamic evaporative ecosystem that receives seawater from below as it is surrounded by sand dunes. We investigated the chemical composition, the microbial activity and biodiversity of the four main layers (L1-L4 in the photosynthetic mats. Chlorophyll a (Chl a concentration and distribution (measured by HPLC and hyperspectral imaging, respectively, the phycocyanin distribution (scanned with hyperspectral imaging, oxygenic photosynthesis (determined by microsensor, and the abundance of photosynthetic microorganisms (from 16S and 18S rRNA sequencing decreased with depth in the euphotic layer (L1. Incident irradiance exponentially attenuated in the same zone reaching 1% at 1.7-mm depth. Proteobacteria dominated all layers of the mat (24%-42% of the identified bacteria. Anoxygenic photosynthetic bacteria (dominated by Chloroflexus were most abundant in the third red layer of the mat (L3, evidenced by the spectral signature of Bacteriochlorophyll as well as by sequencing. The deep, black layer (L4 was dominated by sulfate reducing bacteria belonging to the Deltaproteobacteria, which were responsible for high sulfate reduction rates (measured using 35S tracer. Members of Halobacteria were the dominant Archaea in all layers of the mat (92%-97%, whereas Nematodes were the main Eukaryotes (up to 87%. Primary productivity rates of Um Alhool mat were similar to those of other hypersaline microbial mats. However, sulfate reduction rates were relatively low, indicating that oxygenic respiration contributes more to organic material degradation than sulfate reduction, because of bioturbation. Although Um Alhool hypersaline mat is a nutrient-limited ecosystem, it is interestingly dynamic and phylogenetically highly diverse. All its components work in a highly efficient and synchronized way to compensate for the lack of nutrient supply provided during regular inundation periods.

  13. Community Structure and Activity of a Highly Dynamic and Nutrient-Limited Hypersaline Microbial Mat in Um Alhool Sabkha, Qatar

    KAUST Repository

    Al-Thani, Roda

    2014-03-21

    The Um Alhool area in Qatar is a dynamic evaporative ecosystem that receives seawater from below as it is surrounded by sand dunes. We investigated the chemical composition, the microbial activity and biodiversity of the four main layers (L1–L4) in the photosynthetic mats. Chlorophyll a (Chl a) concentration and distribution (measured by HPLC and hyperspectral imaging, respectively), the phycocyanin distribution (scanned with hyperspectral imaging), oxygenic photosynthesis (determined by microsensor), and the abundance of photosynthetic microorganisms (from 16S and 18S rRNA sequencing) decreased with depth in the euphotic layer (L1). Incident irradiance exponentially attenuated in the same zone reaching 1% at 1.7-mm depth. Proteobacteria dominated all layers of the mat (24%–42% of the identified bacteria). Anoxygenic photosynthetic bacteria (dominated by Chloroflexus) were most abundant in the third red layer of the mat (L3), evidenced by the spectral signature of Bacteriochlorophyll as well as by sequencing. The deep, black layer (L4) was dominated by sulfate reducing bacteria belonging to the Deltaproteobacteria, which were responsible for high sulfate reduction rates (measured using 35S tracer). Members of Halobacteria were the dominant Archaea in all layers of the mat (92%–97%), whereas Nematodes were the main Eukaryotes (up to 87%). Primary productivity rates of Um Alhool mat were similar to those of other hypersaline microbial mats. However, sulfate reduction rates were relatively low, indicating that oxygenic respiration contributes more to organic material degradation than sulfate reduction, because of bioturbation. Although Um Alhool hypersaline mat is a nutrient-limited ecosystem, it is interestingly dynamic and phylogenetically highly diverse. All its components work in a highly efficient and synchronized way to compensate for the lack of nutrient supply provided during regular inundation periods.

  14. Nutrient limitation on ecosystem productivity and processes of mature and old-growth subtropical forests in China.

    Directory of Open Access Journals (Sweden)

    Enqing Hou

    Full Text Available Nitrogen (N is considered the dominant limiting nutrient in temperate regions, while phosphorus (P limitation frequently occurs in tropical regions, but in subtropical regions nutrient limitation is poorly understood. In this study, we investigated N and P contents and N:P ratios of foliage, forest floors, fine roots and mineral soils, and their relationships with community biomass, litterfall C, N and P productions, forest floor turnover rate, and microbial processes in eight mature and old-growth subtropical forests (stand age >80 yr at Dinghushan Biosphere Reserve, China. Average N:P ratios (mass based in foliage, litter (L layer and mixture of fermentation and humus (F/H layer, and fine roots were 28.3, 42.3, 32.0 and 32.7, respectively. These values are higher than the critical N:P ratios for P limitation proposed (16-20 for foliage, ca. 25 for forest floors. The markedly high N:P ratios were mainly attributed to the high N concentrations of these plant materials. Community biomass, litterfall C, N and P productions, forest floor turnover rate and microbial properties were more strongly related to measures of P than N and frequently negatively related to the N:P ratios, suggesting a significant role of P availability in determining ecosystem production and productivity and nutrient cycling at all the study sites except for one prescribed disturbed site where N availability may also be important. We propose that N enrichment is probably a significant driver of the potential P limitation in the study area. Low P parent material may also contribute to the potential P limitation. In general, our results provided strong evidence supporting a significant role for P availability, rather than N availability, in determining ecosystem primary productivity and ecosystem processes in subtropical forests of China.

  15. Employee quality, monitoring environment and internal control

    National Research Council Canada - National Science Library

    Chunli Liu Bin Lin Wei Shu

    2017-01-01

    ... quality.We examine the effect of monitoring on this result and find that the effect is more pronounced for firms with strict monitoring environments, especially when the firms implement the Chinese internal...

  16. NASA's Contributions to Controlled Environment Agriculture

    Science.gov (United States)

    Wheeler, Raymond M.

    2016-01-01

    It may come as a surprise, but NASA has been a long-standing sponsor of controlled environment agriculture (CEA) research. This is based on the potential for using plants (crops) for life support systems in space. Through photosynthesis, crops could produce food and oxygen for humans, while removing CO2. In addition, plant transpiration could help purify waste water. NASAs interest in bioregenerative life support dates back to the late 1950s. At that time, much of the testing focused on algae, but over the years moved toward higher plants as CEA techniques improved. Throughout the 1980s and 90s, extensive testing was carried out at different universities to gather horticultural data for a range of crops, including wheat, soybean, lettuce, potato, sweet potato, cowpea, rice and more. These studies examined different electric light sources, mineral nutrition, recirculating hydroponics, effects of CO2, temperature, photosynthetic photon flux (PPF), and photoperiod on the crops, and identified cultivars that would be useful for space. Findings from these studies were then used to conduct large scale (20 sq m), closed atmosphere tests at Kennedy Space Center, and later at NASA Johnson Space Center, where plant growth chambers were linked to human habitats. Results showed that with high light input and careful horticultural management, about 20-25 sq m of crops under continuous cultivation could produce the O2 for one person, and about 40-50 sq m could produce enough dietary calories. The ability to sustain these production levels and accurately assess system costs and failures needs further study. In all likelihood, the use of plants for life support will evolve, where for early missions like the International Space Station, crops will be grown in small chambers to provide supplemental fresh foods. As mission durations and distances increase, the systems could expand to assume more of the life support burden. But the constraints of space travel require that these

  17. Creative responses needed in controlled environment.

    Science.gov (United States)

    Rogatz, P

    1978-08-01

    Faced with an increasingly regulatory environment, hospitals must find innovative ways by which, first, to survive and, then, to respond constructively to externally applied constraints. Decertification of beds and a move to ambulatory care programs are only two of many possible responses. The key to success will be the measure of cooperation between health care providers, insurers, and government.

  18. Transactions Concurrency Control in Web Service Environment

    DEFF Research Database (Denmark)

    Alrifai, Mohammad; Dolog, Peter; Nejdl, Wolfgang

    2006-01-01

    an engineering point of view as it does not change the way consumers or clients of web services have to be programmed. Furthermore, it avoids direct communication between transaction coordinators which preserves security by keeping the information about business transactions restricted to the coordinators which......Business transactions in web service environments run with relaxed isolation and atomicity property. In such environments, transactions can commit and roll back independently on each other. Transaction management has to reflect this issue and address the problems which result for example from...... concurrent access to web service resources and data. In this paper we propose an extension to the WS-Transaction Protocol which ensures the consistency of the data when independent business transactions access the data concurrently under the relaxed transaction properties. Our extension is based...

  19. Transactions Concurrency Control in Web Service Environment

    DEFF Research Database (Denmark)

    Alrifai, Mohammad; Dolog, Peter; Nejdl, Wolfgang

    2006-01-01

    on transaction dependency graphs maintained at the service provider side. We have implemented such a protocol on top of WS-Transaction. The extension on the web service provider side is simple to achieve as it can be an integral part of the service invocation mechanism. It has also an advantage from...... an engineering point of view as it does not change the way consumers or clients of web services have to be programmed. Furthermore, it avoids direct communication between transaction coordinators which preserves security by keeping the information about business transactions restricted to the coordinators which......Business transactions in web service environments run with relaxed isolation and atomicity property. In such environments, transactions can commit and roll back independently on each other. Transaction management has to reflect this issue and address the problems which result for example from...

  20. Nutrient limits in diets for growing dairy goats Límites nutricionales para dietas de cabras lecheras en crecimiento

    Directory of Open Access Journals (Sweden)

    AL Martínez-Marín

    2012-01-01

    Full Text Available Dry matter intake and nutrient requirements of young growing dairy goats were reviewed in this paper to derive nutrient limits applicable for diet optimization through minimum cost linear programming. The diets offered to growing goats should be optimized from both nutritional and economic view. To get those objectives, the nutritionist has to estimate accurately forage and total dry matter intake, and the nutrient supply and requirements. The reviewed literature suggests that intake of young growing goats ranges between physical and physiological limits imposed by gut fill and energy requirements. The filling effect of the diet is related to its structural carbohydrate content, whereas the physiological satiety effect is related to diet metabolizable energy content. The minimum intake of forage required to keep rumen health is low, whereas maximum forage intake is probably related to the neutral detergent fibre content of the total diet. The energy and protein supply and requirements calculated according to the two most recent feed evaluation systems are similar, what makes no difference using any of both to optimize diets. Recent proposals to calculate calcium and phosphorus supply and requirements provide greater accuracy than the older ones.El objetivo del presente trabajo fue revisar el consumo de materia seca y las necesidades nutritivas de cabras lecheras de reposición estabuladas para establecer límites nutricionales aplicables a la formulación de dietas por programación lineal a mínimo coste. El diseño de dietas nutricionalmente adecuadas y económicas requiere que el nutricionista estime correctamente el consumo de materia seca y forraje y los aportes y las necesidades de nutrientes. La bibliografía revisada sugiere que el consumo total de materia seca de las cabras oscila entre los límites físico y fisiológico impuestos por la capacidad del tracto digestivo y las necesidades energéticas diarias. El efecto de llenado

  1. Controlling social stress in virtual reality environments

    NARCIS (Netherlands)

    Hartanto, D.; Kampmann, I.L.; Morina, N.; Emmelkamp, P.G.M.; Neerincx, M.A.; Brinkman, W.P.

    2014-01-01

    Virtual reality exposure therapy has been proposed as a viable alternative in the treatment of anxiety disorders, including social anxiety disorder. Therapists could benefit from extensive control of anxiety eliciting stimuli during virtual exposure. Two stimuli controls are studied in this study: t

  2. Measles control in the urbanising environment

    African Journals Online (AJOL)

    1991-04-20

    Apr 20, 1991 ... primary health care delivery, thereby making the achievement of 'health for all by .... respectively - similar to the rates in their regions of origin. 19 ..... Walsh JA. Selective primary health care: strategies for control of disease in.

  3. Controlling Social Stress in Virtual Reality Environments

    OpenAIRE

    Hartanto, Dwi; Kampmann, Isabel L.; Morina, Nexhmedin; Paul G M Emmelkamp; Neerincx, Mark A.; Brinkman, Willem-Paul

    2014-01-01

    Virtual reality exposure therapy has been proposed as a viable alternative in the treatment of anxiety disorders, including social anxiety disorder. Therapists could benefit from extensive control of anxiety eliciting stimuli during virtual exposure. Two stimuli controls are studied in this study: the social dialogue situation, and the dialogue feedback responses (negative or positive) between a human and a virtual character. In the first study, 16 participants were exposed in three virtual r...

  4. Controlling social stress in virtual reality environments

    OpenAIRE

    Hartanto, D.; Kampmann, I.L.; Morina, N; Emmelkamp, P.G.M.; Neerincx, M.A.; Brinkman, W.P.

    2014-01-01

    Virtual reality exposure therapy has been proposed as a viable alternative in the treatment of anxiety disorders, including social anxiety disorder. Therapists could benefit from extensive control of anxiety eliciting stimuli during virtual exposure. Two stimuli controls are studied in this study: the social dialogue situation, and the dialogue feedback responses (negative or positive) between a human and a virtual character. In the first study, 16 participants were exposed in three virtual r...

  5. Controlling social stress in virtual reality environments

    OpenAIRE

    Dwi Hartanto; Kampmann, Isabel L.; Nexhmedin Morina; Emmelkamp, Paul G. M.; Neerincx, Mark A.; Willem-Paul Brinkman

    2014-01-01

    Virtual reality exposure therapy has been proposed as a viable alternative in the treatment of anxiety disorders, including social anxiety disorder. Therapists could benefit from extensive control of anxiety eliciting stimuli during virtual exposure. Two stimuli controls are studied in this study: the social dialogue situation, and the dialogue feedback responses (negative or positive) between a human and a virtual character. In the first study, 16 participants were exposed in three virtual r...

  6. Uniformity and control in the pyrotechnic environment

    Energy Technology Data Exchange (ETDEWEB)

    Strubel, S. J. [Harvard Industries Inc., Arnold, MO (United States)

    2000-04-01

    In the production of pyrotechnic materials control is very stringent as dictated by the intrinsic nature of the material. Uniformity is continuous and maintained at a high level. In contrast, once the pyrotechnic material is produced susceptibility towards loss in control begins, given the multiplicity of destination, environmental changes, storage, terrain shooting devices, ignition methods, non-standard state regulations and variations in safety personnel expertise. This author claims that with the advances made in electronic engineering, adoption of electronic control systems could greatly increase uniformity and control. Some of his recommendations include: electronic consoles designed with computers for firing control, choreography and animated lighting displays; microchips embedded in pyrotechnic materials for ease of identification, storage, transportation and display; microchips encased in flash technology to provide ignition, replacing chemical fuses; audible alarms and light signals to alert the operator when the fireworks device is moved to the arming stage, thus preventing inadvertent firing; and electronic sequencers for firing mortars, in one launcher, milliseconds apart, to lessen the impact on launchers. Benefits claimed for these techniques would be increased safety, reduced insurance premiums and claims, and increase in efficiency and most of all, in control.

  7. Control of the aseptic processing environment.

    Science.gov (United States)

    Frieben, W R

    1983-11-01

    Methods used by industry with applications to hospital pharmacy for maintaining an aseptic environment in production of sterile pharmaceutical products are discussed. A major source of product contamination is airborne microorganisms. The laminar-airflow workbench with a high-efficiency particulate air filter provides an ultraclean environment for preparation of sterile products. However, the workbench does not guarantee sterility of products and is not effective if not properly installed and maintained or if the operator uses poor aseptic technique. The laminar-airflow workbench should be tested for leaks, airflow velocity, and airflow patterns when installed, and the workbench should be checked periodically thereafter. The workbench should be placed in a cleanroom where traffic and air disturbances that might affect the laminar airflow are eliminated. A major source of airborne microbial contamination in cleanrooms is people. Personnel movement through an area and presence of personnel without lint-free, nonshedding protective garments increase the levels of microbial contaminants in an area. The transport of nonsterile products (bottles, boxes, paper products) into a cleanroom should be minimized. The cleanroom itself should be sanitized and should be immaculate. Microbial or particulate monitoring should be conducted in the cleanroom using a quantitative method, and corrective-action limits should be set. Hospital pharmacists should examine industrial sterile-processing techniques and apply them to the preparation of sterile products.

  8. Cooperative Control of Distributed Autonomous Vehicles in Adversarial Environments

    Science.gov (United States)

    2006-08-14

    IEEE Transactions on Automatic Control , March 2006. Computation and control language programming environment: Design...to Nash equilibria”, IEEE Transactions on Automatic Control , March 2005. Differential games with probabilistic models: Many representations of...Accepted for publication, IEEE Transactions on Automatic Control , 2006. Language Evolution: This work is indirectly related to the problem of consensus.

  9. Fitting method for hybrid temperature control in smart home environment

    OpenAIRE

    CHENG, Zhuo; TAN, Yasuo; Lim, Azman Osman

    2014-01-01

    The design of control system is crucial for improving the comfort level of home environment. Cyber-Physical Systems (CPSs) can offer numerous opportunities to design high efficient control systems. In this paper, we focus on the design of temperature control systems. By using the idea of CPS, a hybrid temperature control (HTC) system is proposed. It combines supervisory and proportional-integral-derivative (PID) controllers. Through an energy efficient temperature control (EETC) algorithm, HT...

  10. Exploring the relationship between personal control and the hospital environment.

    Science.gov (United States)

    Williams, Anne M; Dawson, Sky; Kristjanson, Linda J

    2008-06-01

    This paper describes the further development of the substantive theory Optimising Personal Control to Facilitate Emotional Comfort. In previous work, emotional comfort was identified as a therapeutic state that was influenced by several factors, one of which was the hospital environment. This paper focuses on aspects within the hospital environment that patients perceive to influence their feelings of personal control. A relationship between control and health has been discussed in previous literature. There are indications that aspects of the hospital environment can impact on a patient's perception of control. This project explored personal control in relation to the hospital environment from the perspective of patients. Grounded theory method was used. Data were collected from patients' interviews and field observations and analysed using the constant comparative method. Interviews were tape-recorded and transcribed verbatim. A qualitative data computer program was used to manage the data. The results confirmed the findings of the original study where hospitalised patients were found to experience feelings of reduced personal control. The conditions of level of security, level of knowing and level of personal value were described in terms of their contribution to the patient's feelings of personal control. Specific directions for further research into the development and evaluation of therapeutic hospital environments that promote personal control and the associated emotional comfort are provided. This research highlights the importance of considering patients' feelings of personal control during their hospital stay. Several directions for establishment of therapeutic environments within hospitals are provided, but more research in this area is recommended.

  11. History and applications in controlled environments

    Science.gov (United States)

    Downs, R. J.

    1994-01-01

    The widespread application of electric (often called artificial) light in greenhouses, growing rooms, and plant growth chambers would presuppose that the role of phytochrome would be considered in the selection and use of such lighting systems. Unfortunately this is not usually the case. Part of the problem is that many students, and indeed an unfortunate number of senior scientists, seem to regard phytochrome as a laboratory phenomenon without much application in the real world. They simply have not grasped the concept that phytochrome is functioning through all stages of plant development, wherever plants are grown. It is certainly true, as Meijer (1971) stated, that one cannot compare experimental results obtained under very strict laboratory conditions with plant irradiation in glasshouses and in growth rooms. When Karl Norris developed the first practical portable spectroradiometer about 1962, some of the first measurements were to determine the red/far-red ratios under tree canopies. These measurements showed clearly the predominance of far-red in the understory and suggested that far-red was contributing to the elongation exhibited by many species growing in the shade, and possibly was a factor in the induction of light requirements in seeds. Subsequently we used Catalpa leaves as far-red filters to make light-insensitive lettuce seed light requiring. Much more detailed work has since been done on phytochrome effects in the natural environment, and it is encouraging to note that efforts are bring made to apply phytochrome research to horticulture.

  12. Intelligent Mobile Robot Motion Control in Unstructured Environments

    Directory of Open Access Journals (Sweden)

    Gyula Mester

    2010-11-01

    Full Text Available This paper presents the intelligent wheeled mobile robot motion control inunstructured environments. The fuzzy control of a wheeled mobile robot motion inunstructured environments with obstacles and slopes is proposed. Outputs of the fuzzycontroller are the angular speed difference between the left and right wheels of the mobilerobot and the mobile robot velocity. The simulation results show the effectiveness and thevalidity of the obstacle avoidance behavior in an unstructured environment and the velocitycontrol of a wheeled mobile robot motion of the proposed fuzzy control strategy. Wirelesssensor-based remote control of mobile robots motion in unstructured environments usingthe Sun SPOT technology is proposed. The proposed method has been implemented on theminiature mobile robot Khepera that is equipped with sensors. Finally, the effectivenessand efficiency of the proposed sensor-based remote control strategy are demonstrated byexperimental studies and good experimental results.

  13. CPG Control for Biped Hopping Robot in Unpredictable Environment

    Institute of Scientific and Technical Information of China (English)

    Tingting Wang; Wei Guo; Mantian Li; Fusheng Zha; Lining Sun

    2012-01-01

    A CPG control mechanism is proposed for hopping motion control of biped robot in unpredictable environment.Based on analysis of robot motion and biological observation of animal's control mechanism,the motion control task is divided into two simple parts:motion sequence control and output force control.Inspired by a two-level CPG model,a two-level CPG control mechanism is constructed to coordinate the drivers of robot joint,while various feedback information are introduced into the control mechanism.Interneurons within the control mechanism are modeled to generate motion rhythm and pattern promptly for motion sequence control; motoneurons are modeled to control output forces of joint drivers in real time according to feedbacks.The control system can perceive changes caused by unknown perturbations and environment changes according to feedback information,and adapt to unpredictable environment by adjusting outputs of neurons.The control mechanism is applied to a biped hopping robot in unpredictable environment on simulation platform,and stable adaptive motions are obtained.

  14. The metabolic response of P. putida KT2442 producing high levels of polyhydroxyalkanoate under single- and multiple-nutrient-limited growth: Highlights from a multi-level omics approach

    Directory of Open Access Journals (Sweden)

    Poblete-Castro Ignacio

    2012-03-01

    Full Text Available Abstract Background Pseudomonas putida KT2442 is a natural producer of polyhydroxyalkanoates (PHAs, which can substitute petroleum-based non-renewable plastics and form the basis for the production of tailor-made biopolymers. However, despite the substantial body of work on PHA production by P. putida strains, it is not yet clear how the bacterium re-arranges its whole metabolism when it senses the limitation of nitrogen and the excess of fatty acids as carbon source, to result in a large accumulation of PHAs within the cell. In the present study we investigated the metabolic response of KT2442 using a systems biology approach to highlight the differences between single- and multiple-nutrient-limited growth in chemostat cultures. Results We found that 26, 62, and 81% of the cell dry weight consist of PHA under conditions of carbon, dual, and nitrogen limitation, respectively. Under nitrogen limitation a specific PHA production rate of 0.43 (g·(g·h-1 was obtained. The residual biomass was not constant for dual- and strict nitrogen-limiting growth, showing a different feature in comparison to other P. putida strains. Dual limitation resulted in patterns of gene expression, protein level, and metabolite concentrations that substantially differ from those observed under exclusive carbon or nitrogen limitation. The most pronounced differences were found in the energy metabolism, fatty acid metabolism, as well as stress proteins and enzymes belonging to the transport system. Conclusion This is the first study where the interrelationship between nutrient limitations and PHA synthesis has been investigated under well-controlled conditions using a system level approach. The knowledge generated will be of great assistance for the development of bioprocesses and further metabolic engineering work in this versatile organism to both enhance and diversify the industrial production of PHAs.

  15. Probabilistically Safe Vehicle Control in a Hostile Environment

    OpenAIRE

    Cizelj, Igor; Ding, Xu Chu; Lahijanian, Morteza; Pinto, Alessandro; Belta, Calin

    2011-01-01

    In this paper we present an approach to control a vehicle in a hostile environment with static obstacles and moving adversaries. The vehicle is required to satisfy a mission objective expressed as a temporal logic specification over a set of properties satisfied at regions of a partitioned environment. We model the movements of adversaries in between regions of the environment as Poisson processes. Furthermore, we assume that the time it takes for the vehicle to traverse in between two facets...

  16. Human response to an individually controlled environment

    DEFF Research Database (Denmark)

    Knudsen, G.L.; Melikov, Arsen Krikor

    2005-01-01

    -desk air terminal device supplying cool air, a chair with convectively heated backrest, an under-desk radiant heating panel and a floor-heating panel. The temperature of the PV air and the under-desk air was kept at 20 degrees C. The subjects were provided with control of the flow rate and direction...... of the personalized air and under-desk airflow rate, the temperature of the convection flow from the chair, and the surface temperature of the heating panels. The results reveal that the thermal and air quality acceptability was significantly higher with the ICS at all room temperatures compared to the reference...... condition. The ICS could satisfy more than 85% of the subjects in regard to both thermal comfort and inhaled air quality....

  17. CONTROL OF INDOOR ENVIRONMENTS VIA THE REGULATION OF BUILDING ENVELOPES

    Directory of Open Access Journals (Sweden)

    Mitja Košir

    2011-01-01

    Full Text Available The design of comfortable, healthy and stimulating indoor environments in buildings has a direct impact on the users and on energy consumption, as well as on the wider soci-economic environment of society.The indoor environment of buildings is defined with the formulation of the building envelope, which functions as an interface between the internal and external environments and its users. A properly designed, flexible and adequately controlled building envelope is a starting point in the formulation of a high-quality indoor environment. The systematic treatment of the indoor environment and building envelope from a user’s point of view represents an engineering approach that enables the holistic treatment of buildings, as well as integrated components and systems. The presented division of indoor environment in terms of visual, thermal, olfactory, acoustic and ergonomic sub-environments enables the classification and selection of crucial factors influencing design. This selection and classification can be implemented in the design, as well as in control applications of the building envelope. The implementation of the approach described is demonstrated with an example of an automated control system for the internal environment of an office in the building of the Faculty of Civil and Geodetic Engineering.

  18. Parental Low Self-Control, Family Environments, and Juvenile Delinquency.

    Science.gov (United States)

    Meldrum, Ryan C; Connolly, George M; Flexon, Jamie; Guerette, Rob T

    2016-10-01

    Research consistently finds that low self-control is significantly correlated with delinquency. Only recently, however, have researchers started to examine associations between parental low self-control, family environments, and child antisocial behavior. Adding to this emerging area of research, the current study examines associations between parental low self-control, aspects of the family environment, and officially recoded juvenile delinquency among a sample (N = 101) of juveniles processed through a juvenile justice assessment facility located in the Southeastern United States. Furthermore, it considers whether aspects of family environments, particularly family cohesion, family conflict, and parental efficacy, mediate the influence of parental low self-control on delinquency. The results of a series of analyses indicate that parental low self-control is correlated with various aspects of family environments and juvenile delinquency, and that the association between parental low self-control and juvenile delinquency is mediated by family environments. Supplementary analyses also suggest that the association between parental low self-control and the family environment may be reciprocal.

  19. Integrated control of the South African border environment

    CSIR Research Space (South Africa)

    Taute, BJE

    2007-03-01

    Full Text Available security, trade and tourism. Control of the border environment is inherently a multi-departmental responsibility, requiring extensive communication and coordination across departments, agencies and provinces, and covering the whole of the South African...

  20. Gaseous emissions from plants in controlled environments

    Science.gov (United States)

    Dubay, Denis T.

    1988-01-01

    Plant growth in a controlled ecological life support system may entail the build-up over extended time periods of phytotoxic concentrations of volatile organic compounds produced by the plants themselves. Ethylene is a prominent gaseous emission of plants, and is the focus of this report. The objective was to determine the rate of ethylene release by spring wheat, white potato, and lettuce during early, middle, and late growth stages, and during both the light and dark segments of the diurnal cycle. Plants grown hydroponically using the nutrient film technique were covered with plexiglass containers for 4 to 6 h. At intervals after enclosure, gas samples were withdrawn with a syringe and analyzed for ethylene with a gas chromatograph. Lettuce produced 10 to 100 times more ethylene than wheat or potato, with production rates ranging from 141 to 158 ng g-dry/wt/h. Wheat produced from 1.7 to 14.3 ng g-dry/wt/h, with senescent wheat producing the least amount and flowering wheat the most. Potatoes produced the least amount of ethylene, with values never exceeding 5 ng g-dry/wt/h. Lettuce and potatoes each produced ethylene at similar rates whether in dark period or light period. Ethylene sequestering of 33 to 43 percent by the plexiglass enclosures indicated that these production estimates may be low by one-third to one-half. These results suggest that concern for ethylene build-up in a contained atmosphere should be greatest when growing lettuce, and less when growing wheat or potato.

  1. Environment-sensitive manipulator control. [real time, decision making computer aided control

    Science.gov (United States)

    Bejczy, A. K.

    1974-01-01

    Environment-sensitive manipulator control (control systems capable of controlling manipulator motion based on real-time response to sensor data obtained during the attempt to perform a requested task) is described, and experiments on (1) proximity control in manipulation and (2) application of an articulated and adaptively controlled hand-to-environment-sensitive manipulator control are reported. The efficiency of such systems is determined by the separation of control and data processing functions between operator and computer.

  2. Efficient identity management and access control in cloud environment

    Science.gov (United States)

    Gloster, Jonathan

    2013-05-01

    As more enterprises are enticed to move data to a cloud environment to enhance data sharing and reduce operating costs by exploiting shared resources, concerns have risen over the ability to secure information within the cloud. This paper examines how a traditional Identity and Access Control (IDAM) architecture can be adapted to address security concerns of a cloud environment. We propose changing the paradigm of IDAM form a pure trust model to a risk based model will enable information to be protected securely in a cloud environment without impacting efficiencies of cloud environments.

  3. A Platform-independent Programming Environment for Robot Control

    CERN Document Server

    Reckhaus, Michael; Ploeger, Paul G; Kraetzschmar, Gerhard K

    2010-01-01

    The development of robot control programs is a complex task. Many robots are different in their electrical and mechanical structure which is also reflected in the software. Specific robot software environments support the program development, but are mainly text-based and usually applied by experts in the field with profound knowledge of the target robot. This paper presents a graphical programming environment which aims to ease the development of robot control programs. In contrast to existing graphical robot programming environments, our approach focuses on the composition of parallel action sequences. The developed environment allows to schedule independent robot actions on parallel execution lines and provides mechanism to avoid side-effects of parallel actions. The developed environment is platform-independent and based on the model-driven paradigm. The feasibility of our approach is shown by the application of the sequencer to a simulated service robot and a robot for educational purpose.

  4. Mobile robot navigation in unknown static environments using ANFIS controller

    Directory of Open Access Journals (Sweden)

    Anish Pandey

    2016-09-01

    Full Text Available Navigation and obstacle avoidance are the most important task for any mobile robots. This article presents the Adaptive Neuro-Fuzzy Inference System (ANFIS controller for mobile robot navigation and obstacle avoidance in the unknown static environments. The different sensors such as ultrasonic range finder sensor and sharp infrared range sensor are used to detect the forward obstacles in the environments. The inputs of the ANFIS controller are obstacle distances obtained from the sensors, and the controller output is a robot steering angle. The primary objective of the present work is to use ANFIS controller to guide the mobile robot in the given environments. Computer simulations are conducted through MATLAB software and implemented in real time by using C/C++ language running Arduino microcontroller based mobile robot. Moreover, the successful experimental results on the actual mobile robot demonstrate the effectiveness and efficiency of the proposed controller.

  5. Integrated control algorithms for plant environment in greenhouse

    Science.gov (United States)

    Zhang, Kanyu; Deng, Lujuan; Gong, Youmin; Wang, Shengxue

    2003-09-01

    In this paper a survey of plant environment control in artificial greenhouse was put forward for discussing the future development. Firstly, plant environment control started with the closed loop control of air temperature in greenhouse. With the emergence of higher property computer, the adaptive control algorithm and system identification were integrated into the control system. As adaptation control is more depending on observation of variables by sensors and yet many variables are unobservable or difficult to observe, especially for observation of crop growth status, so model-based control algorithm were developed. In order to evade modeling difficulty, one method is predigesting the models and the other method is utilizing fuzzy logic and neural network technology that realize the models by the black box and gray box theory. Studies on control method of plant environment in greenhouse by means of expert system (ES) and artificial intelligence (AI) have been initiated and developed. Nowadays, the research of greenhouse environment control focus on energy saving, optimal economic profit, enviornment protection and continualy develop.

  6. Stability of Unfalsified Adaptive Switching Control in Noisy Environments

    NARCIS (Netherlands)

    Battistelli, Giorgio; Mosca, Edoardo; Safonov, Michael G.; Tesi, Pietro

    2010-01-01

    In recent years, unfalsified adaptive switching control has emerged as a promising technique for the control of uncertain plants only on the basis of plant I/O data. This note analyzes the input-output stability of the resulting switched system in a noisy environment, and discusses the issue of equi

  7. The KALI multi-arm robot programming and control environment

    Science.gov (United States)

    Backes, Paul; Hayati, Samad; Hayward, Vincent; Tso, Kam

    1989-01-01

    The KALI distributed robot programming and control environment is described within the context of its use in the Jet Propulsion Laboratory (JPL) telerobot project. The purpose of KALI is to provide a flexible robot programming and control environment for coordinated multi-arm robots. Flexibility, both in hardware configuration and software, is desired so that it can be easily modified to test various concepts in robot programming and control, e.g., multi-arm control, force control, sensor integration, teleoperation, and shared control. In the programming environment, user programs written in the C programming language describe trajectories for multiple coordinated manipulators with the aid of KALI function libraries. A system of multiple coordinated manipulators is considered within the programming environment as one motion system. The user plans the trajectory of one controlled Cartesian frame associated with a motion system and describes the positions of the manipulators with respect to that frame. Smooth Cartesian trajectories are achieved through a blending of successive path segments. The manipulator and load dynamics are considered during trajectory generation so that given interface force limits are not exceeded.

  8. Quasi serializable concurrency control in mobile broadcast environments

    Institute of Scientific and Technical Information of China (English)

    Dang Depeng; Liu Yunsheng

    2007-01-01

    The problem of maintaining data consistency in mobile broadcast environments is researched.Quasi serializability is formally defined and analyzed at first.It was shown that quasi serializability is less stringent than serializability when database consistency is maintained for transactions.Then,corresponding concurrency control protocol that supports both update transactions and read-only transactions is outlined for mobile broadcast environments.Finally,the simulation results confirmed that the proposed protocol could improve the response time significantly.

  9. Complex conditional control by pigeons in a continuous virtual environment.

    Science.gov (United States)

    Qadri, Muhammad A J; Reid, Sean; Cook, Robert G

    2016-01-01

    We tested two pigeons in a continuously streaming digital environment. Using animation software that constantly presented a dynamic, three-dimensional (3D) environment, the animals were tested with a conditional object identification task. The correct object at a given time depended on the virtual context currently streaming in front of the pigeon. Pigeons were required to accurately peck correct target objects in the environment for food reward, while suppressing any pecks to intermixed distractor objects which delayed the next object's presentation. Experiment 1 established that the pigeons' discrimination of two objects could be controlled by the surface material of the digital terrain. Experiment 2 established that the pigeons' discrimination of four objects could be conjunctively controlled by both the surface material and topography of the streaming environment. These experiments indicate that pigeons can simultaneously process and use at least two context cues from a streaming environment to control their identification behavior of passing objects. These results add to the promise of testing interactive digital environments with animals to advance our understanding of cognition and behavior.

  10. Modeling and control for closed environment plant production systems

    Science.gov (United States)

    Fleisher, David H.; Ting, K. C.; Janes, H. W. (Principal Investigator)

    2002-01-01

    A computer program was developed to study multiple crop production and control in controlled environment plant production systems. The program simulates crop growth and development under nominal and off-nominal environments. Time-series crop models for wheat (Triticum aestivum), soybean (Glycine max), and white potato (Solanum tuberosum) are integrated with a model-based predictive controller. The controller evaluates and compensates for effects of environmental disturbances on crop production scheduling. The crop models consist of a set of nonlinear polynomial equations, six for each crop, developed using multivariate polynomial regression (MPR). Simulated data from DSSAT crop models, previously modified for crop production in controlled environments with hydroponics under elevated atmospheric carbon dioxide concentration, were used for the MPR fitting. The model-based predictive controller adjusts light intensity, air temperature, and carbon dioxide concentration set points in response to environmental perturbations. Control signals are determined from minimization of a cost function, which is based on the weighted control effort and squared-error between the system response and desired reference signal.

  11. Evolution of Neural Controllers for Robot Navigation in Human Environments

    Directory of Open Access Journals (Sweden)

    Genci Capi

    2010-01-01

    Full Text Available Problem statement: In this study, we presented a novel vision-based learning approach for autonomous robot navigation. Approach: In our method, we converted the captured image in a binary one, which after the partition is used as the input of the neural controller. Results: The neural control system, which maps the visual information to motor commands, is evolved online using real robots. Conclusion/Recommendations: We showed that evolved neural networks performed well in indoor human environments. Furthermore, we compared the performance of neural controllers with an algorithmic vision based control method.

  12. Fertilization for High Yields in Corn-Sweet Potato-Wheat Rotation: A Systematic Approach to Nutrient Limiting Factors of Soils in Chongqing, China

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A systematic approach was adopted to investigate the nutrient limiting factors in gray-brown purple soils and yellow soils derived from limestone in Chongqing, China, to study balanced fertilization for corn, sweet potato and wheat in rotation. The results showed that N, P and K were deficient in both soils, Cu, Mn, S andZn in the gray-brown purple soils and Ca, Mg, Mo and Zn for the yellow soils. Balanced fertilizer application increased yields of corn, sweet potato and wheat by 28.4%, 28.7% and 4.4%, respectively, as compared to the local farmers' practice. The systematic approach can be considered as one of the most efficient and reliable methods in fertility study.

  13. Novel hybrid adaptive controller for manipulation in complex perturbation environments.

    Directory of Open Access Journals (Sweden)

    Alex M C Smith

    Full Text Available In this paper we present a hybrid control scheme, combining the advantages of task-space and joint-space control. The controller is based on a human-like adaptive design, which minimises both control effort and tracking error. Our novel hybrid adaptive controller has been tested in extensive simulations, in a scenario where a Baxter robot manipulator is affected by external disturbances in the form of interaction with the environment and tool-like end-effector perturbations. The results demonstrated improved performance in the hybrid controller over both of its component parts. In addition, we introduce a novel method for online adaptation of learning parameters, using the fuzzy control formalism to utilise expert knowledge from the experimenter. This mechanism of meta-learning induces further improvement in performance and avoids the need for tuning through trial testing.

  14. Novel Hybrid Adaptive Controller for Manipulation in Complex Perturbation Environments

    Science.gov (United States)

    Smith, Alex M. C.; Yang, Chenguang; Ma, Hongbin; Culverhouse, Phil; Cangelosi, Angelo; Burdet, Etienne

    2015-01-01

    In this paper we present a hybrid control scheme, combining the advantages of task-space and joint-space control. The controller is based on a human-like adaptive design, which minimises both control effort and tracking error. Our novel hybrid adaptive controller has been tested in extensive simulations, in a scenario where a Baxter robot manipulator is affected by external disturbances in the form of interaction with the environment and tool-like end-effector perturbations. The results demonstrated improved performance in the hybrid controller over both of its component parts. In addition, we introduce a novel method for online adaptation of learning parameters, using the fuzzy control formalism to utilise expert knowledge from the experimenter. This mechanism of meta-learning induces further improvement in performance and avoids the need for tuning through trial testing. PMID:26029916

  15. Expert system for controlling plant growth in a contained environment

    Science.gov (United States)

    May, George A. (Inventor); Lanoue, Mark Allen (Inventor); Bethel, Matthew (Inventor); Ryan, Robert E. (Inventor)

    2011-01-01

    In a system for optimizing crop growth, vegetation is cultivated in a contained environment, such as a greenhouse, an underground cavern or other enclosed space. Imaging equipment is positioned within or about the contained environment, to acquire spatially distributed crop growth information, and environmental sensors are provided to acquire data regarding multiple environmental conditions that can affect crop development. Illumination within the contained environment, and the addition of essential nutrients and chemicals are in turn controlled in response to data acquired by the imaging apparatus and environmental sensors, by an "expert system" which is trained to analyze and evaluate crop conditions. The expert system controls the spatial and temporal lighting pattern within the contained area, and the timing and allocation of nutrients and chemicals to achieve optimized crop development. A user can access the "expert system" remotely, to assess activity within the growth chamber, and can override the "expert system".

  16. Homeostasis control of building environment using sensor agent robot

    Science.gov (United States)

    Nagahama, Eri; Mita, Akira

    2012-04-01

    A human centered system for building is demanded to meet variety of needs due to the diversification and maturation of society. Smart buildings and smart houses have been studied to satisfy this demand. However, it is difficult for such systems to respond flexibly to unexpected events and needs that are caused by aging and complicate emotion changes. With this regards, we suggest "Biofied Buildings". The goal for this research is to realize buildings that are safer, more comfortable and more energy-efficient by embedding adaptive functions of life into buildings. In this paper, we propose a new control system for building environments, focused on physiological adaptation, particularly homeostasis, endocrine system and immune system. Residents are used as living sensors and controllers in the control loop. A sensor agent robot is used to acquire resident's discomfort feeling, and to output hormone-like signals to activate devices to control the environments. The proposed system could control many devices without establishing complicated scenarios. Results obtained from some simulations and the demonstration experiments using an LED lighting system showed that the proposed system were able to achieve robust and stable control of environments without complicated scenarios.

  17. Magnetic fluid readily controlled in zero gravity environment

    Science.gov (United States)

    Papell, S. S.

    1965-01-01

    Colloid composed of finely ground iron oxide in a fluid such as heptane, is controlled and directed magnetically in a zero gravity environment. It will not separate on standing for long periods or after exposure to magnetic or centrifugal forces. Because of its low density and low viscosity, it is easily pumped.

  18. Reliability Architecture for Collaborative Robot Control Systems in Complex Environments

    Directory of Open Access Journals (Sweden)

    Liang Tang

    2016-02-01

    Full Text Available Many different kinds of robot systems have been successfully deployed in complex environments, while research into collaborative control systems between different robots, which can be seen as a hybrid internetware safety-critical system, has become essential. This paper discusses ways to construct robust and secure reliability architecture for collaborative robot control systems in complex environments. First, the indication system for evaluating the realtime reliability of hybrid internetware systems is established. Next, a dynamic collaborative reliability model for components of hybrid internetware systems is proposed. Then, a reliable, adaptive and evolutionary computation method for hybrid internetware systems is proposed, and a timing consistency verification solution for collaborative robot control internetware applications is studied. Finally, a multi-level security model supporting dynamic resource allocation is established.

  19. Controlled environment crop production - Hydroponic vs. lunar regolith

    Science.gov (United States)

    Bugbee, Bruce G.; Salisbury, Frank B.

    1989-01-01

    The potential of controlled environment crop production in a lunar colony is discussed. Findings on the effects of optimal root-zone and aerial environments derived as part of the NASA CELSS project at Utah State are presented. The concept of growing wheat in optimal environment is discussed. It is suggested that genetic engineering might produce the ideal wheat cultivar for CELSS (about 100 mm in height with fewer leaves). The Utah State University hydroponic system is outlined and diagrams of the system and plant container construction are provided. Ratio of plant mass to solution mass, minimum root-zone volume, maintenance, and pH control are discussed. A comparison of liquid hydrophonic systems and lunar regoliths as substrates for plant growth is provided. The physiological processes that are affected by the root-zone environment are discussed including carbon partitioning, nutrient availability, nutrient absorption zones, root-zone oxygen, plant water potential, root-produced hormones, and rhizosphere pH control.

  20. Weak Serializable Concurrency Control in Real-time Broadcast Environments

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Given the asymmetric communication capabilities in mobile real-time environments, traditional serializability-based approaches are too restrictive, unnecessary, and impractical. Thus propose the use of a new weaker correctness criterion is proposed. This paper first formally defines the new notion of correctness called weak serializability. After the necessary and sufficient conditions for weak serializability are shown, corresponding concurrency control protocol based on this criterion is outlined for real-time broadcast environments. Finally, the simulation results confirmed that the proposed techniques help mobile transactions to meet their deadlines and improve query response time.

  1. Distributed Motor Controller (DMC) for Operation in Extreme Environments

    Science.gov (United States)

    McKinney, Colin M.; Yager, Jeremy A.; Mojarradi, Mohammad M.; Some, Rafi; Sirota, Allen; Kopf, Ted; Stern, Ryan; Hunter, Don

    2012-01-01

    This paper presents an extreme environment capable Distributed Motor Controller (DMC) module suitable for operation with a distributed architecture of future spacecraft systems. This motor controller is designed to be a bus-based electronics module capable of operating a single Brushless DC motor in extreme space environments: temperature (-120 C to +85 C required, -180 C to +100 C stretch goal); radiation (>;20K required, >;100KRad stretch goal); >;360 cycles of operation. Achieving this objective will result in a scalable modular configuration for motor control with enhanced reliability that will greatly lower cost during the design, fabrication and ATLO phases of future missions. Within the heart of the DMC lies a pair of cold-capable Application Specific Integrated Circuits (ASICs) and a Field Programmable Gate Array (FPGA) that enable its miniaturization and operation in extreme environments. The ASICs are fabricated in the IBM 0.5 micron Silicon Germanium (SiGe) BiCMOS process and are comprised of Analog circuitry to provide telemetry information, sensor interface, and health and status of DMC. The FPGA contains logic to provide motor control, status monitoring and spacecraft interface. The testing and characterization of these ASICs have yielded excellent functionality in cold temperatures (-135 C). The DMC module has demonstrated successful operation of a motor at temperature.

  2. Modeling and Control of Livestock Ventilation Systems and Indoor Environments

    DEFF Research Database (Denmark)

    Wu, Zhuang; Heiselberg, Per; Stoustrup, Jakob

    2005-01-01

    constraints and random disturbances is designed through system linearization. The well designed control systems are able to determine the demand ventilation rate and airflow pattern, improve and optimize the indoor Thermal Comfort (TC), Indoor Air Quality (IAQ) and energy use.......The hybrid ventilation systems have been widely used for livestock barns to provide optimum indoor climate by controlling the ventilation rate and air flow distribution within the ventilated building structure. The purpose of this paper is to develop models for livestock ventilation systems...... and indoor environments with a major emphasis on the prediction of indoor horizontal variation of temperature and concentration adapted to the design of appropriate controlling strategy and control systems. The Linear Quadratic (LQ) optimal control method taking into account of the effect of necessary...

  3. Multiagent Flight Control in Dynamic Environments with Cooperative Coevolutionary Algorithms

    Science.gov (United States)

    Knudson, Matthew D.; Colby, Mitchell; Tumer, Kagan

    2014-01-01

    Dynamic flight environments in which objectives and environmental features change with respect to time pose a difficult problem with regards to planning optimal flight paths. Path planning methods are typically computationally expensive, and are often difficult to implement in real time if system objectives are changed. This computational problem is compounded when multiple agents are present in the system, as the state and action space grows exponentially. In this work, we use cooperative coevolutionary algorithms in order to develop policies which control agent motion in a dynamic multiagent unmanned aerial system environment such that goals and perceptions change, while ensuring safety constraints are not violated. Rather than replanning new paths when the environment changes, we develop a policy which can map the new environmental features to a trajectory for the agent while ensuring safe and reliable operation, while providing 92% of the theoretically optimal performance

  4. Access control management for e-Healthcare in cloud environment

    Directory of Open Access Journals (Sweden)

    Lili Sun

    2014-03-01

    Full Text Available Data outsourcing is a major component for cloud computing that allows data owners to distribute resources to external services for users and organizations who can apply the resources. A crucial problem for owners is how to make sure their sensitive information accessed by legitimate users only using the trusted services but not authorized to read the actual information. With the increased development of cloud computing, it brings challenges for data security and access control when outsourcing users’ data and sharing sensitive data in cloud environment since it is not within the same trusted domain as data owners’. Access control policies have become an important issue in the security filed in cloud computing. Semantic web technologies represent much richer forms of relationships among users, resources and actions among different web applications such as clouding computing. However, Semantic web applications pose new requirements for security mechanisms especially in the access control models. This paper addresses existing access control methods and presents a semantic based access control model which considers semantic relations among different entities in cloud computing environment. We have enriched the research for semantic web technology with role-based access control that is able to be applied in the field of medical information system or e-Healthcare system. This work shows how the semantic web technology provides efficient solutions for the management of complex and distributed data in heterogeneous systems, and it can be used in the medical information systems as well.

  5. Molecular specificity, convergence and constraint shape adaptive evolution in nutrient-poor environments.

    Directory of Open Access Journals (Sweden)

    Jungeui Hong

    2014-01-01

    Full Text Available One of the central goals of evolutionary biology is to explain and predict the molecular basis of adaptive evolution. We studied the evolution of genetic networks in Saccharomyces cerevisiae (budding yeast populations propagated for more than 200 generations in different nitrogen-limiting conditions. We find that rapid adaptive evolution in nitrogen-poor environments is dominated by the de novo generation and selection of copy number variants (CNVs, a large fraction of which contain genes encoding specific nitrogen transporters including PUT4, DUR3 and DAL4. The large fitness increases associated with these alleles limits the genetic heterogeneity of adapting populations even in environments with multiple nitrogen sources. Complete identification of acquired point mutations, in individual lineages and entire populations, identified heterogeneity at the level of genetic loci but common themes at the level of functional modules, including genes controlling phosphatidylinositol-3-phosphate metabolism and vacuole biogenesis. Adaptive strategies shared with other nutrient-limited environments point to selection of genetic variation in the TORC1 and Ras/PKA signaling pathways as a general mechanism underlying improved growth in nutrient-limited environments. Within a single population we observed the repeated independent selection of a multi-locus genotype, comprised of the functionally related genes GAT1, MEP2 and LST4. By studying the fitness of individual alleles, and their combination, as well as the evolutionary history of the evolving population, we find that the order in which these mutations are acquired is constrained by epistasis. The identification of repeatedly selected variation at functionally related loci that interact epistatically suggests that gene network polymorphisms (GNPs may be a frequent outcome of adaptive evolution. Our results provide insight into the mechanistic basis by which cells adapt to nutrient-limited environments

  6. Integrated controlling technique of ecological environment in Shendong Mining Area

    Institute of Scientific and Technical Information of China (English)

    ZHANG Dong-sheng; LIU Yu-de; WANG An; WANG Yi

    2007-01-01

    To enclose the interactive relation between the underground mining with suitable protection for surface ecological environments and surface prevention of ecological environments adapting to mining disturbing was researched and developed core of this technique. There are three aspects of controlling ecological environments, to dispose and renew before exploitation, to protect surface ecological environments in the exploitative process and to repair and build up after exploitation. Based on the moving law of overburden strata in shallow seam, the surface subsidence law and the growth law of vegetation in subsidence mine area, the integrated controlling technique has been developed synthetically by methods of theoretic analysis, laboratory simulation, numerical calculation,commercial test etc.. It includes the key techniques of aquifer-protective mining, filtering and purging of mine water through goaf, preventing and extinguishing fire in shallow seam,no-rock roadway layout and waste disposal in underground, frame-building ecological functional sphere before exploitation, frame-building the ecological cycle using system after mining and so on.

  7. Development of visual 3D virtual environment for control software

    Science.gov (United States)

    Hirose, Michitaka; Myoi, Takeshi; Amari, Haruo; Inamura, Kohei; Stark, Lawrence

    1991-01-01

    Virtual environments for software visualization may enable complex programs to be created and maintained. A typical application might be for control of regional electric power systems. As these encompass broader computer networks than ever, construction of such systems becomes very difficult. Conventional text-oriented environments are useful in programming individual processors. However, they are obviously insufficient to program a large and complicated system, that includes large numbers of computers connected to each other; such programming is called 'programming in the large.' As a solution for this problem, the authors are developing a graphic programming environment wherein one can visualize complicated software in virtual 3D world. One of the major features of the environment is the 3D representation of concurrent process. 3D representation is used to supply both network-wide interprocess programming capability (capability for 'programming in the large') and real-time programming capability. The authors' idea is to fuse both the block diagram (which is useful to check relationship among large number of processes or processors) and the time chart (which is useful to check precise timing for synchronization) into a single 3D space. The 3D representation gives us a capability for direct and intuitive planning or understanding of complicated relationship among many concurrent processes. To realize the 3D representation, a technology to enable easy handling of virtual 3D object is a definite necessity. Using a stereo display system and a gesture input device (VPL DataGlove), our prototype of the virtual workstation has been implemented. The workstation can supply the 'sensation' of the virtual 3D space to a programmer. Software for the 3D programming environment is implemented on the workstation. According to preliminary assessments, a 50 percent reduction of programming effort is achieved by using the virtual 3D environment. The authors expect that the 3D

  8. Nutrient Limitation in the Precambrian

    Science.gov (United States)

    Planavsky, N. J.; Lalonde, S.; Konhauser, K.; Lyons, T. W.

    2010-04-01

    We present Fe and P concentrations from distal hydrothermal sediments and iron formations through time in order to evaluate the evolution of the marine P reservoir. P concentrations appear to have been elevated in Precambrian oceans.

  9. Proposed congestion control method for cloud computing environments

    CERN Document Server

    Kuribayashi, Shin-ichi

    2012-01-01

    As cloud computing services rapidly expand their customer base, it has become important to share cloud resources, so as to provide them economically. In cloud computing services, multiple types of resources, such as processing ability, bandwidth and storage, need to be allocated simultaneously. If there is a surge of requests, a competition will arise between these requests for the use of cloud resources. This leads to the disruption of the service and it is necessary to consider a measure to avoid or relieve congestion of cloud computing environments. This paper proposes a new congestion control method for cloud computing environments which reduces the size of required resource for congested resource type instead of restricting all service requests as in the existing networks. Next, this paper proposes the user service specifications for the proposed congestion control method, and clarifies the algorithm to decide the optimal size of required resource to be reduced, based on the load offered to the system. I...

  10. Budgetary control in a “just in time” environment

    OpenAIRE

    Ioan Constantin Dima; Liliana Ivănuţ

    2002-01-01

    Budgetary control in a “Just In Time” environment is based on a new industrial organization, with only two levels of authority: workshops or homogeneous work units and budgetary centers. Each budgetary center generates it’s own costs and responsibilities and refers only to these. The system is oriented to the future and the performance to obtain is evaluated starting from an adjustment coefficient, which shows the improvement effort reported to initial budget

  11. Demographic and Commercial Environments and Building Control Customer Services

    Directory of Open Access Journals (Sweden)

    Hope Peter

    2016-01-01

    Full Text Available A simple and cost effective business analytics schema developed in this study provides a basis for observing how demographic and commercial environmental impacts affect building control customer services. In order to overlay environmental impacts onto building control services, schematic mapping of resource distributions and services were plotted according to corporate jurisdiction, corporate virtues and customer type characteristics. Quantitative and qualitative surveys were conducted on corporate staff and material resources, business performance measures and targets, building control service manager observations and demographic and commercial environments. Results from this research provide a single view corporate map of people, material resources, and service performance in relation to customer characteristics, while reaching out to better understand the building control customer experience, general public expectation and market influences. In this regard, this research can provide a foundation for realising corporate virtue aspirations.

  12. Heterologous expression of Anabaena PCC 7120 all3940 (a Dps family gene) protects Escherichia coli from nutrient limitation and abiotic stresses

    Energy Technology Data Exchange (ETDEWEB)

    Narayan, Om Prakash; Kumari, Nidhi [Molecular Biology Section, Laboratory of Algal Biology, Center of Advanced Study in Botany, Banaras Hindu University, Varanasi-22 1005 (India); Rai, Lal Chand, E-mail: lcraibhu@gmail.com [Molecular Biology Section, Laboratory of Algal Biology, Center of Advanced Study in Botany, Banaras Hindu University, Varanasi-22 1005 (India)

    2010-03-26

    This study presents first hand data on the cloning and heterologous expression of Anabaena PCC 7120 all3940 (a dps family gene) in combating nutrients limitation and multiple abiotic stresses. The Escherichia coli transformed with pGEX-5X-2-all3940 construct when subjected to iron, carbon, nitrogen, phosphorus limitation and carbofuron, copper, UV-B, heat, salt and cadmium stress registered significant increase in growth over the cells transformed with empty vector under iron (0%), carbon (0.05%), nitrogen (3.7 mM) and phosphorus (2 mM) limitation and carbofuron (0.025 mg ml{sup -1}), CuCl{sub 2} (1 mM), UV-B (10 min), heat (47 {sup o}C), NaCl (6% w/v) and CdCl{sub 2} (4 mM) stress. Enhanced expression of all3940 gene measured by semi-quantitative RT-PCR at different time points under above mentioned treatments clearly demonstrates its role in tolerance against aforesaid abiotic stresses. This study opens the gate for developing transgenic cyanobacteria capable of growing successfully under above mentioned stresses.

  13. Genes in new environments: genetics and evolution in biological control.

    Science.gov (United States)

    Roderick, George K; Navajas, Maria

    2003-11-01

    The availability of new genetic technologies has positioned the field of biological control as a test bed for theories in evolutionary biology and for understanding practical aspects of the release of genetically manipulated material. Purposeful introductions of pathogens, parasites, predators and herbivores, when considered as replicated semi-natural field experiments, show the unpredictable nature of biological colonization. The characteristics of organisms and their environments that determine this variation in the establishment and success of biological control can now be explored using genetic tools. Lessons from studies of classical biological control can help inform researchers and policy makers about the risks that are associated with the release of genetically modified organisms, particularly with respect to long-term evolutionary changes.

  14. Fuzzy control of mobile robot in slippery environment

    Directory of Open Access Journals (Sweden)

    Nabil Hassan Hadi

    2005-01-01

    Full Text Available The problem of independent motion control of mobile robot (МR in conditions when unforeseen changes of conditions of interaction of wheels with a surface are considered. An example of such changes can be sudden entrance МR a slippery surface. The deployment of an autonomous unmanned ground vehicle for field applications provides the means by which the risk to personnel can be minimized and operational capabilities improved. In rough terrain, it is critical for mobile robots to maintain good wheel traction. Wheel slip could cause the rover to lose control and become trapped. This paper describes the application of fuzzy control to a feedback system within slippery environment. The study is conducted on an example of МR with two driving wheels.

  15. BIODEGRABILITY OF BIOPLASTIC MATERIALS IN A CONTROLLED COMPOSTING ENVIRONMENT

    Directory of Open Access Journals (Sweden)

    Magdalena Daria Vaverková

    2015-06-01

    Full Text Available The objective of this study was to determine the biodegradability of bioplastic materials – sponge cloths – available on the European market that are labeled as 100% biodegradable but not certified as compostable. The test was carried out in a controlled composting environment. The project length was 22 weeks. The emphasis was put on discovering whether the sponge cloths are biodegradable or not. Based on the results thereof it can be concluded that sponge cloths have not decomposed completely but their color has changed and that degradation and physical changes occurred. Samples A1, and A2 have not decomposed completely and exhibited very slow degradation rate. Sample B5 exhibited the highest degradation rate. Samples B3, B4 exhibited high degree of decomposition. The main conclusion from this study is that biodegradation of bioplastics materials strongly depends on both the environment in which they are placed and the chemical nature of the material.

  16. Noise Pollution Control System in the Hospital Environment

    Science.gov (United States)

    Figueroa Gallo, LM; Olivera, JM

    2016-04-01

    Problems related to environmental noise are not a new subject, but they became a major issue to solve because of the increasing, in complexity and intensity, of human activities due technological advances. Numerous international studies had dealt with the exposure of critical patients to noisy environment such as the Neonatal Intensive Care Units; their results show that there are difficulties in the organization in the developing brain, it can damage the delicate auditory structures and can cause biorhythm disorders, specially in preterm infants. The objective of this paper is to present the development and implementation of a control system that includes technical-management-training aspects to regulate the levels of specific noise sources in the neonatal hospitalization environment. For this purpose, there were applied different tools like: observations, surveys, procedures, an electronic control device and a training program for a Neonatal Service Unit. As a result, all noise sources were identified -some of them are eliminable-; all the service stable staff categories participated voluntarily; environmental noise measurements yielded values between 62.5 and 64.6 dBA and maximum were between 86.1 and 89.7 dBA; it was designed and installed a noise control device and the staff is being trained in noise reduction best practices.

  17. Leg compliance control of a hexapod robot based on improved adaptive control in different environments

    Institute of Scientific and Technical Information of China (English)

    朱雅光; 金波; 李伟

    2015-01-01

    Considering the compliance control problem of a hexapod robot under different environments, a control strategy based on the improved adaptive control algorithm is proposed. The model of robot structure and impedance control is established. Then, the indirect adaptive control algorithm is derived. Through the analysis of its parameters, it can be noticed that the algorithm does not meet the requirements of the robot compliance control in a complex environment. Therefore, the fuzzy control algorithm is used to adjust the adaptive control parameters. The satisfied system response can be obtained based on the adjustment in real time according to the error between input and output. Comparative experiments and analysis of traditional adaptive control and the improved adaptive control algorithm are presented. It can be verified that not only desired contact force can be reached quickly in different environments, but also smaller contact impact and sliding avoidance are guaranteed, which means that the control strategy has great significance to enhance the adaptability of the hexapod robot.

  18. Infinitely dimensional control Markov branching chains in random environments

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    First of all we introduce the concepts of infinitely dimensional control Markov branching chains in random environments (β-MBCRE) and prove the existence of such chains, then we introduce the concepts of conditional generating functionals and random Markov transition functions of such chains and investigate their branching property. Base on these concepts we calculate the moments of the β-MBCRE and obtain the main results of this paper such as extinction probabilities, polarization and proliferation rate. Finally we discuss the classification ofβ-MBCRE according to the different standards.

  19. Stimulating productivity of hydroponic lettuce in controlled environments with triacontanol

    Science.gov (United States)

    Knight, S. L.; Mitchell, C. A.

    1987-01-01

    Triacontanol (1-triacontanol) applied as a foliar spray at 10(-7) M to 4-day-old, hydroponically grown leaf lettuce (Lactuca sativa L.) seedlings in a controlled environment increased leaf fresh and dry weight 13% to 20% and root fresh and dry weight 13% to 24% 6 days after application, relative to plants sprayed with water. When applied at 8 as well as 4 days after seeding, triacontanol increased plant fresh and dry weight, leaf area, and mean relative growth rate 12% to 37%. There was no benefit of repeating application of triacontanol in terms of leaf dry weight gain.

  20. DESIGN OF ROBOTIC COLONIZER CONTROL SYSTEM FOR AQUEOUS ENVIRONMENT

    Directory of Open Access Journals (Sweden)

    C.VENKATESH

    2013-05-01

    Full Text Available Now a days there is a huge interest on underwater communication systems for various applications in order to explore aqueous environments. Intelligent robots and cooperative multi- agent robotic systems can be very efficient tools to speed up search and research operations in remote areas. Robots are also useful to do jobs inareas and in situations that are hazardous for human, they can go anywhere that is not reachable my humans and can go into gaps and move trough small holes that are impossible for humans and even trained dogs. in this paper, a wireless underwater mobile robot system is designed in order to study the behavior of artemia group. anew idea has been presented for underwater mobile robot system which is consists of two parts, first is the underwater mechanical robot and the second is ZigBee wireless based mobile robot which controls and moves the first part. by this system different patterns motion control (linear, circular, zigzag, etc. has been performed and proved the ability to control group of robot by controlling the group of artemia and monitoring the underwater mobile robot control with the help of water proof RF wireless camera and also explore the details present around the mobile robot

  1. Metadata Control Agent approach for Replication in Grid Environments

    Directory of Open Access Journals (Sweden)

    P. SunilGavaskar

    2013-10-01

    Full Text Available since grid environment is dynamic, network latency and user requests may change. In order to provide better communication, access time and fault tolerant in decentralized systems, the replication is a technique to reduce access time, storage space. The objective of the work is to propose an agent control approach for Heterogeneous environments using the Agents for storing objects as replicas in decentralized environments. Our idea minimizes the more replicas (i.e. causes overhead on response time and update cost, therefore maintaining suitable number of replicas is important. Fixed replicas provides file access structure to identify the esteem files and gives optimal replication location, which minimize replication issues like access time and update cost by assuming a given traffic pattern. In this context we present the Agents as replicas to maintain a suitable scalable architecture. The solution uses fewer replicas, which lead to fewer agents as a result of that frequent updating is possible. Our tests show that the proposed strategy outperforms previous solutions in terms of replication issues.

  2. Supervisory control of multiple robots in dynamic tasking environments.

    Science.gov (United States)

    Chen, Jessie Y C; Barnes, Michael J

    2012-01-01

    A military targeting environment was simulated to examine the effects of an intelligent route-planning agent RoboLeader, which could support dynamic robot re-tasking based on battlefield developments, on the performance of robotics operators. We manipulated the level of assistance (LOAs) provided by RoboLeader as well as the presence of a visualisation tool that provided feedback to the participants on their primary task (target encapsulation) performance. Results showed that the participants' primary task benefited from RoboLeader on all LOAs conditions compared to manual performance; however, visualisation had little effect. Frequent video gamers demonstrated significantly better situation awareness of the mission environment than did infrequent gamers. Those participants with higher spatial ability performed better on a secondary target detection task than did those with lower spatial ability. Finally, participants' workload assessments were significantly lower when they were assisted by RoboLeader than when they performed the target entrapment task manually. Practitioner Summary: This study demonstrated the utility of an intelligent agent for enhancing robotics operators' supervisory control performance as well as reducing their workload during a complex urban scenario involving moving targets. The results furthered the understanding of the interplay among level-of-autonomy, multitasking performance and individual differences in military tasking environments.

  3. Maximizing Information on the Environment by Dynamically Controlled Qubit Probes

    Science.gov (United States)

    Zwick, Analia; Álvarez, Gonzalo A.; Kurizki, Gershon

    2016-01-01

    We explore the ability of a qubit probe to characterize unknown parameters of its environment. By resorting to the quantum estimation theory, we analytically find the ultimate bound on the precision of estimating key parameters of a broad class of ubiquitous environmental noises ("baths") which the qubit may probe. These include the probe-bath coupling strength, the correlation time of generic types of bath spectra, and the power laws governing these spectra, as well as their dephasing times T2. Our central result is that by optimizing the dynamical control on the probe under realistic constraints one may attain the maximal accuracy bound on the estimation of these parameters by the least number of measurements possible. Applications of this protocol that combines dynamical control and estimation theory tools to quantum sensing are illustrated for a nitrogen-vacancy center in diamond used as a probe.

  4. Head Tracking Based Avatar Control for Virtual Environment Teamwork Training

    Directory of Open Access Journals (Sweden)

    Stefan Marks

    2012-12-01

    Full Text Available Virtual environments (VE are gaining in popularity and are increasingly used for teamwork training purposes, e.g., for medical teams. One shortcoming of modern VEs is that nonverbal communication channels, essential for teamwork, are not supported well. We address this issue by using an inexpensive webcam to track the user's head. This tracking information is used to control the head movement of the user's avatar, thereby conveying head gestures and adding a nonverbal communication channel. We conducted a user study investigating the influence of head tracking based avatar control on the perceived realism of the VE and on the performance of a surgical teamwork training scenario. Our results show that head tracking positively influences the perceived realism of the VE and the communication, but has no major influence on the training outcome.

  5. Maximizing information on the environment by dynamically controlled qubit probes

    CERN Document Server

    Zwick, Analia; Kurizki, Gershon

    2015-01-01

    We explore the ability of a qubit probe to characterize unknown parameters of its environment. By resorting to quantum estimation theory, we analytically find the ultimate bound on the precision of estimating key parameters of a broad class of ubiquitous environmental noises ("baths") which the qubit may probe. These include the probe-bath coupling strength, the correlation time of generic bath spectra, the power laws governing these spectra, as well as their dephasing times T2. Our central result is that by optimizing the dynamical control on the probe under realistic constraints one may attain the maximal accuracy bound on the estimation of these parameters by the least number of measurements possible. Applications of this protocol that combines dynamical control and estimation theory tools to quantum sensing are illustrated for a nitrogen-vacancy center in diamond used as a probe.

  6. Does the Environment Responsibility Affect the Management Control System?

    Directory of Open Access Journals (Sweden)

    Hichem DKHILI

    2013-06-01

    Full Text Available The literature suggests a problem emerging between management controls systems with the new responsibilities that companies must take into consideration. This study examines a system design management control tool orientation as behaviors that can overcome the uncertainties related to the environment and register the company in a voluntary approach which takes into account the environmental dimensions. A questionnaire survey sent to 306 Tunisian industrial companies was conducted. The results of the exploratory and confirmatory analysis are required. The results of the principal component factor analysis evidenced by Cronbach's alpha and KMO test, helped to cleanse the items selected from the literature. Similarly, the results of structural equations with indices of structural adjustment and parcimonies have devoted a good quality adjustment. Overall, findings suggest that most of the firm’s environment is uncertain, more tools to include in its environmental dimensions. On the other hand, the voluntary integration of an environmental approach is part of a strategy of cost leadership in the Tunisian industrial companies.

  7. Understanding Plant-Soil Relationships Using Controlled Environment Facilities

    Science.gov (United States)

    Andersen, C. P.; Rygiewicz, P. T.

    1999-01-01

    Although soil is a component of terrestrial ecosystems, it is comprised of a complex web of interacting organisms, and therefore can be considered itself as an ecosystem. Soil microflora and fauna derive energy from plants and plant residues and serve important functions in maintaining soil physical and chemical properties, thereby affecting net primary productivity (NPP), and in the case of contained environments, the quality of the life support system. We have been using 3 controlled-environment facilities (CEF's) that incorporate different levels of soil biological complexity and environmental control, and differ in their resemblance to natural ecosystems, to study relationships among plant physiology, soil ecology, fluxes of minerals and nutrients, and overall ecosystem function. The simplest system utilizes growth chambers and specialized root chambers with organic-less media to study the physiology of plant-mycorrhizal associations. A second system incorporates natural soil in open-top chambers to study soil bacterial and fungal population response to stress. The most complex CEF incorporates reconstructed soil profiles in a ``constructed'' ecosystem, enabling close examination of the soil foodweb. Our results show that closed ecosystem research is important for understanding mechanisms of response to ecosystem stresses. In addition, responses observed at one level of biological complexity may not allow prediction of response at a different level of biological complexity. In closed life support systems, incorporating soil foodwebs will require less artificial manipulation to maintain system stability and sustainability.

  8. Interaction Effects of Light, Temperature and Nutrient Limitations (N, P and Si) on Growth, Stoichiometry and Photosynthetic Parameters of the Cold-Water Diatom Chaetoceros wighamii.

    Science.gov (United States)

    Spilling, Kristian; Ylöstalo, Pasi; Simis, Stefan; Seppälä, Jukka

    2015-01-01

    Light (20-450 μmol photons m(-2) s(-1)), temperature (3-11 °C) and inorganic nutrient composition (nutrient replete and N, P and Si limitation) were manipulated to study their combined influence on growth, stoichiometry (C:N:P:Chl a) and primary production of the cold water diatom Chaetoceros wighamii. During exponential growth, the maximum growth rate (~0.8 d(-1)) was observed at high temperature and light; at 3 °C the growth rate was ~30% lower under similar light conditions. The interaction effect of light and temperature were clearly visible from growth and cellular stoichiometry. The average C:N:P molar ratio was 80:13:1 during exponential growth, but the range, due to different light acclimation, was widest at the lowest temperature, reaching very low C:P (~50) and N:P ratios (~8) at low light and temperature. The C:Chl a ratio had also a wider range at the lowest temperature during exponential growth, ranging 16-48 (weight ratio) at 3 °C compared with 17-33 at 11 °C. During exponential growth, there was no clear trend in the Chl a normalized, initial slope (α*) of the photosynthesis-irradiance (PE) curve, but the maximum photosynthetic production (P(m)) was highest for cultures acclimated to the highest light and temperature. During the stationary growth phase, the stoichiometric relationship depended on the limiting nutrient, but with generally increasing C:N:P ratio. The average photosynthetic quotient (PQ) during exponential growth was 1.26 but decreased to nutrient and light limitation, probably due to photorespiration. The results clearly demonstrate that there are interaction effects between light, temperature and nutrient limitation, and the data suggests greater variability of key parameters at low temperature. Understanding these dynamics will be important for improving models of aquatic primary production and biogeochemical cycles in a warming climate.

  9. Interaction Effects of Light, Temperature and Nutrient Limitations (N, P and Si on Growth, Stoichiometry and Photosynthetic Parameters of the Cold-Water Diatom Chaetoceros wighamii.

    Directory of Open Access Journals (Sweden)

    Kristian Spilling

    Full Text Available Light (20-450 μmol photons m(-2 s(-1, temperature (3-11 °C and inorganic nutrient composition (nutrient replete and N, P and Si limitation were manipulated to study their combined influence on growth, stoichiometry (C:N:P:Chl a and primary production of the cold water diatom Chaetoceros wighamii. During exponential growth, the maximum growth rate (~0.8 d(-1 was observed at high temperature and light; at 3 °C the growth rate was ~30% lower under similar light conditions. The interaction effect of light and temperature were clearly visible from growth and cellular stoichiometry. The average C:N:P molar ratio was 80:13:1 during exponential growth, but the range, due to different light acclimation, was widest at the lowest temperature, reaching very low C:P (~50 and N:P ratios (~8 at low light and temperature. The C:Chl a ratio had also a wider range at the lowest temperature during exponential growth, ranging 16-48 (weight ratio at 3 °C compared with 17-33 at 11 °C. During exponential growth, there was no clear trend in the Chl a normalized, initial slope (α* of the photosynthesis-irradiance (PE curve, but the maximum photosynthetic production (P(m was highest for cultures acclimated to the highest light and temperature. During the stationary growth phase, the stoichiometric relationship depended on the limiting nutrient, but with generally increasing C:N:P ratio. The average photosynthetic quotient (PQ during exponential growth was 1.26 but decreased to <1 under nutrient and light limitation, probably due to photorespiration. The results clearly demonstrate that there are interaction effects between light, temperature and nutrient limitation, and the data suggests greater variability of key parameters at low temperature. Understanding these dynamics will be important for improving models of aquatic primary production and biogeochemical cycles in a warming climate.

  10. LTL Control in Uncertain Environments with Probabilistic Satisfaction Guarantees

    CERN Document Server

    Ding, Xu Chu; Belta, Calin; Rus, Daniela

    2011-01-01

    We present a method to generate a robot control strategy that maximizes the probability to accomplish a task. The task is given as a Linear Temporal Logic (LTL) formula over a set of properties that can be satisfied at the regions of a partitioned environment. We assume that the probabilities with which the properties are satisfied at the regions are known, and the robot can determine the truth value of a proposition only at the current region. Motivated by several results on partitioned-based abstractions, we assume that the motion is performed on a graph. To account for noisy sensors and actuators, we assume that a control action enables several transitions with known probabilities. We show that this problem can be reduced to the problem of generating a control policy for a Markov Decision Process (MDP) such that the probability of satisfying an LTL formula over its states is maximized. We provide a complete solution for the latter problem that builds on existing results from probabilistic model checking. W...

  11. Web based remote monitoring and controlling system for vulnerable environments

    Science.gov (United States)

    Thomas, Aparna; George, Minu

    2016-03-01

    The two major areas of concern in industrial establishments are monitoring and security. The remote monitoring and controlling can be established with the help of Web technology. Managers can monitor and control the equipment in the remote area through a web browser. The targeted area includes all type of susceptible environment like gas filling station, research and development laboratories. The environmental parameters like temperature, light intensity, gas etc. can be monitored. Security is a very important factor in an industrial setup. So motion detection feature is added to the system to ensure the security. The remote monitoring and controlling system makes use of the latest, less power consumptive and fast working microcontroller like S3C2440. This system is based on ARM9 and Linux operating system. The ARM9 will collect the sensor data and establish real time video monitoring along with motion detection feature. These captured video data as well as environmental data is transmitted over internet using embedded web server which is integrated within the ARM9 board.

  12. An artificial reality environment for remote factory control and monitoring

    Science.gov (United States)

    Kosta, Charles Paul; Krolak, Patrick D.

    1993-01-01

    Work has begun on the merger of two well known systems, VEOS (HITLab) and CLIPS (NASA). In the recent past, the University of Massachusetts Lowell developed a parallel version of NASA CLIPS, called P-CLIPS. This modification allows users to create smaller expert systems which are able to communicate with each other to jointly solve problems. With the merger of a VEOS message system, PCLIPS-V can now act as a group of entities working within VEOS. To display the 3D virtual world we have been using a graphics package called HOOPS, from Ithaca Software. The artificial reality environment we have set up contains actors and objects as found in our Lincoln Logs Factory of the Future project. The environment allows us to view and control the objects within the virtual world. All communication between the separate CLIPS expert systems is done through VEOS. A graphical renderer generates camera views on X-Windows devices; Head Mounted Devices are not required. This allows more people to make use of this technology. We are experimenting with different types of virtual vehicles to give the user a sense that he or she is actually moving around inside the factory looking ahead through windows and virtual monitors.

  13. NASA's Controlled Environment Agriculture Testing for Space Habitats

    Science.gov (United States)

    Wheeler, Raymond M.

    2014-01-01

    NASA and other space agencies have an interest in using plants for human life support in space. The plants could provide food and O2 for the humans, while removing CO2 and helping purify wastewater. Studies to date have shown that a wide range of crops can be grown in controlled environment conditions envisioned for space. Light is a critical factor both for crop productivity and system power costs, and recent improvements in LEDs make them a preferred lighting option for space. Because space systems would be tightly closed, issues such as ethylene build-up and management must be considered. Ultimately, the costs and reliability of biological life support options must be compared with more conventional life support approaches. Findings to date suggest that about 20-25 sq. meters of crops could supply the O2 for one human, while about 50 sq. meters would be required for food (dietary calories).

  14. Air traffic control by distributed management in a MLS environment

    Science.gov (United States)

    Kreifeldt, J. G.; Parkin, L.; Hart, S.

    1977-01-01

    The microwave landing system (MLS) is a technically feasible means for increasing runway capacity since it could support curved approaches to a short final. The shorter the final segment of the approach, the wider the variety of speed mixes possible so that theoretically, capacity would ultimately be limited by runway occupance time only. An experiment contrasted air traffic control in a MLS environment under a centralized form of management and under distributed management which was supported by a traffic situation display in each of the 3 piloted simulators. Objective flight data, verbal communication and subjective responses were recorded on 18 trial runs lasting about 20 minutes each. The results were in general agreement with previous distributed management research. In particular, distributed management permitted a smaller spread of intercrossing times and both pilots and controllers perceived distributed management as the more 'ideal' system in this task. It is concluded from this and previous research that distributed management offers a viable alternative to centralized management with definite potential for dealing with dense traffic in a safe, orderly and expeditious manner.

  15. Limits of Executive Control: Sequential Effects in Predictable Environments.

    Science.gov (United States)

    Verbruggen, Frederick; McAndrew, Amy; Weidemann, Gabrielle; Stevens, Tobias; McLaren, Ian P L

    2016-05-01

    Cognitive-control theories attribute action control to executive processes that modulate behavior on the basis of expectancy or task rules. In the current study, we examined corticospinal excitability and behavioral performance in a go/no-go task. Go and no-go trials were presented in runs of five, and go and no-go runs alternated predictably. At the beginning of each trial, subjects indicated whether they expected a go trial or a no-go trial. Analyses revealed that subjects immediately adjusted their expectancy ratings when a new run started. However, motor excitability was primarily associated with the properties of the previous trial, rather than the predicted properties of the current trial. We also observed a large latency cost at the beginning of a go run (i.e., reaction times were longer for the first trial in a go run than for the second trial). These findings indicate that actions in predictable environments are substantially influenced by previous events, even if this influence conflicts with conscious expectancies about upcoming events. © The Author(s) 2016.

  16. DURIP: Piezoresponse Force Microscope (PFM) with Controlled Environment for Characterization of Flexoelectric Nanostructures

    Science.gov (United States)

    2015-04-21

    DURIP: Piezoresponse Force Microscope (PFM) with Controlled Environment for Characterization of Flexoelectric Nanostructures A piezo-force... microscope (PFM) system was acquired under this support for characterization of flexoelectric micro/nanostructures in a controlled environment. The system...published in non peer-reviewed journals: Final Report: DURIP: Piezoresponse Force Microscope (PFM) with Controlled Environment for Characterization of

  17. Integrated software environment dedicated for implementation of control systems based on PLC controllers

    Directory of Open Access Journals (Sweden)

    Szymon SURMA

    2007-01-01

    Full Text Available Industrial processes’ control systems based on PLC controllers play today a very important role in all fields of transport, including also sea transport. Construction of control systems is the field of engineering, which has been continuously evolving towards maximum simplification of system design path. Up to now the time needed forthe system construction from the design to commissioning had to be divided into a few stages. A mistake made in an earlier stage caused that in most cases the next stages had to be restarted. Available debugging systems allows defect detection at an early stage of theproject implementation. The paper presents general characteristic of integrated software for implementation of complex control systems. The issues related to the software use for programming of the visualisation environment, control computer, selection oftransmission medium and transmission protocol as well as PLC controllers’ configuration, software and control have been analysed.

  18. Central automatic control or distributed occupant control for better indoor environment quality in the future

    DEFF Research Database (Denmark)

    Toftum, Jørn

    2008-01-01

    of adverse symptoms and building related symptoms than the ventilation mode per se. This result indicates that even though the development and application of new indoor environment sensors and HVAC control systems may allow for fully automated IEQ control, such systems should not compromise occupants...... in the degree of perceived control. The database was composed of 1353 responses obtained in 25 buildings of which 15 had mechanical ventilation (997 responses) and 9 had natural ventilation (275 responses). Analysis of occupant responses, after grouping according to categories determined by the degree...... of satisfaction with the perceived control, showed that the degree of control satisfaction, but rarely building category (natural vs. mechanical ventilation), affected the prevalence of adverse perceptions and symptoms. Thus, the degree of control, as perceived by occupants, was more important for the prevalence...

  19. Central automatic control or distributed occupant control for better indoor environment quality in the future

    DEFF Research Database (Denmark)

    Toftum, Jørn

    2010-01-01

    a discrepancy in the degree of perceived control. The database was composed of 1272 responses obtained in 24 buildings of which 15 had mechanical ventilation (997 responses) and 9 had natural ventilation (275 responses). The number of occupant-reported control opportunities was higher in buildings with natural...... ventilation. Analysis of occupant responses, after grouping according to categories determined by the degree of satisfaction with the perceived control, showed that it was more likely the degree of control satisfaction that affected the prevalence of adverse perceptions and symptoms. Thus, the degree...... of control, as perceived by occupants, seemed more important for the prevalence of adverse symptoms and building-related symptoms than the ventilation mode per se. This result indicates that even though the development and application of new indoor environment sensors and HVAC control systems may allow...

  20. Simulation model for plant growth in controlled environment systems

    Science.gov (United States)

    Raper, C. D., Jr.; Wann, M.

    1986-01-01

    The role of the mathematical model is to relate the individual processes to environmental conditions and the behavior of the whole plant. Using the controlled-environment facilities of the phytotron at North Carolina State University for experimentation at the whole-plant level and methods for handling complex models, researchers developed a plant growth model to describe the relationships between hierarchial levels of the crop production system. The fundamental processes that are considered are: (1) interception of photosynthetically active radiation by leaves, (2) absorption of photosynthetically active radiation, (3) photosynthetic transformation of absorbed radiation into chemical energy of carbon bonding in solube carbohydrates in the leaves, (4) translocation between carbohydrate pools in leaves, stems, and roots, (5) flow of energy from carbohydrate pools for respiration, (6) flow from carbohydrate pools for growth, and (7) aging of tissues. These processes are described at the level of organ structure and of elementary function processes. The driving variables of incident photosynthetically active radiation and ambient temperature as inputs pertain to characterization at the whole-plant level. The output of the model is accumulated dry matter partitioned among leaves, stems, and roots; thus, the elementary processes clearly operate under the constraints of the plant structure which is itself the output of the model.

  1. Surface chemistry of black phosphorus under a controlled oxidative environment

    Science.gov (United States)

    Luo, Wei; Zemlyanov, Dmitry Y.; Milligan, Cory A.; Du, Yuchen; Yang, Lingming; Wu, Yanqing; Ye, Peide D.

    2016-10-01

    Black phosphorus (BP), the bulk counterpart of monolayer phosphorene, is a relatively stable phosphorus allotrope at room temperature. However, monolayer phosphorene and ultra-thin BP layers degrade in ambient atmosphere. In this paper, we report the investigation of BP oxidation and discuss the reaction mechanism based on the x-ray photoelectron spectroscopy (XPS) data. The kinetics of BP oxidation was examined under various well-controlled conditions, namely in 5% O2/Ar, 2.3% H2O/Ar, and 5% O2 and 2.3% H2O/Ar. At room temperature, the BP surface is demonstrated not to be oxidized at a high oxidation rate in 5% O2/Ar nor in 2.3% H2O/Ar, according to XPS, with the thickness of the oxidized phosphorus layer <5 Å for 5 h. On the other hand, in the O2/H2O mixture, a 30 Å thickness oxide layer was detected already after 2 h of the treatment. This result points to a synergetic effect of water and oxygen in the BP oxidation. The oxidation effect was also studied in applications to the electrical measurements of BP field-effect transistors (FETs) with or without passivation. The electrical performance of BP FETs with atomic layer deposition (ALD) dielectric passivation or h-BN passivation formed in a glove-box environment are also presented.

  2. Environment

    DEFF Research Database (Denmark)

    Valentini, Chiara

    2017-01-01

    The term environment refers to the internal and external context in which organizations operate. For some scholars, environment is defined as an arrangement of political, economic, social and cultural factors existing in a given context that have an impact on organizational processes and structures....... For others, environment is a generic term describing a large variety of stakeholders and how these interact and act upon organizations. Organizations and their environment are mutually interdependent and organizational communications are highly affected by the environment. This entry examines the origin...... and development of organization-environment interdependence, the nature of the concept of environment and its relevance for communication scholarships and activities....

  3. Active route learning in virtual environments: disentangling movement control from intention, instruction specificity, and navigation control.

    Science.gov (United States)

    von Stülpnagel, Rul; Steffens, Melanie C

    2013-09-01

    Active navigation research examines how physiological and psychological involvement in navigation benefits spatial learning. However, existing conceptualizations of active navigation comprise separable, distinct factors. This research disentangles the contributions of movement control (i.e., self-contained vs. observed movement) as a central factor from learning intention (Experiment 1), instruction specificity and instruction control (Experiment 2), as well as navigation control (Experiment 3) to spatial learning in virtual environments. We tested the effects of these factors on landmark recognition (landmark knowledge), tour-integration and route navigation (route knowledge). Our findings suggest that movement control leads to robust advantages in landmark knowledge as compared to observed movement. Advantages in route knowledge do not depend on learning intention, but on the need to elaborate spatial information. Whenever the necessary level of elaboration is assured for observed movement, too, the development of route knowledge is not inferior to that for self-contained movement.

  4. A Distributed Control System Prototyping Environment to Support Control Room Modernization

    Energy Technology Data Exchange (ETDEWEB)

    Lew, Roger Thomas [Idaho National Lab. (INL), Idaho Falls, ID (United States); Boring, Ronald Laurids [Idaho National Lab. (INL), Idaho Falls, ID (United States); Ulrich, Thomas Anthony [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2014-12-01

    Operators of critical processes, such as nuclear power production, must contend with highly complex systems, procedures, and regulations. Developing human-machine interfaces (HMIs) that better support operators is a high priority for ensuring the safe and reliable operation of critical processes. Human factors engineering (HFE) provides a rich and mature set of tools for evaluating the performance of HMIs, however the set of tools for developing and designing HMIs is still in its infancy. Here we propose a rapid prototyping approach for integrating proposed HMIs into their native environments before a design is finalized. This approach allows researchers and developers to test design ideas and eliminate design flaws prior to fully developing the new system. We illustrate this approach with four prototype designs developed using Microsoft’s Windows Presentation Foundation (WPF). One example is integrated into a microworld environment to test the functionality of the design and identify the optimal level of automation for a new system in a nuclear power plant. The other three examples are integrated into a full-scale, glasstop digital simulator of a nuclear power plant. One example demonstrates the capabilities of next generation control concepts; another aims to expand the current state of the art; lastly, an HMI prototype was developed as a test platform for a new control system currently in development at U.S. nuclear power plants. WPF possesses several characteristics that make it well suited to HMI design. It provides a tremendous amount of flexibility, agility, robustness, and extensibility. Distributed control system (DCS) specific environments tend to focus on the safety and reliability requirements for real-world interfaces and consequently have less emphasis on providing functionality to support novel interaction paradigms. Because of WPF’s large user-base, Microsoft can provide an extremely mature tool. Within process control applications,WPF is

  5. Adaptation of a Control Center Development Environment for Industrial Process Control

    Science.gov (United States)

    Killough, Ronnie L.; Malik, James M.

    1994-01-01

    In the control center, raw telemetry data is received for storage, display, and analysis. This raw data must be combined and manipulated in various ways by mathematical computations to facilitate analysis, provide diversified fault detection mechanisms, and enhance display readability. A development tool called the Graphical Computation Builder (GCB) has been implemented which provides flight controllers with the capability to implement computations for use in the control center. The GCB provides a language that contains both general programming constructs and language elements specifically tailored for the control center environment. The GCB concept allows staff who are not skilled in computer programming to author and maintain computer programs. The GCB user is isolated from the details of external subsystem interfaces and has access to high-level functions such as matrix operators, trigonometric functions, and unit conversion macros. The GCB provides a high level of feedback during computation development that improves upon the often cryptic errors produced by computer language compilers. An equivalent need can be identified in the industrial data acquisition and process control domain: that of an integrated graphical development tool tailored to the application to hide the operating system, computer language, and data acquisition interface details. The GCB features a modular design which makes it suitable for technology transfer without significant rework. Control center-specific language elements can be replaced by elements specific to industrial process control.

  6. Control of the Environment in the Operating Room.

    Science.gov (United States)

    Katz, Jonathan D

    2016-09-23

    There is a direct relationship between the quality of the environment of a workplace and the productivity and efficiency of the work accomplished. Components such as temperature, humidity, ventilation, drafts, lighting, and noise each contribute to the quality of the overall environment and the sense of well-being of those who work there.The modern operating room is a unique workplace with specific, and frequently conflicting, environmental requirements for each of the inhabitants. Even minor disturbances in the internal environment of the operating room can have serious ramifications on the comfort, effectiveness, and safety of each of the inhabitants. A cool, well-ventilated, and dry climate is optimal for many members of the surgical team. Any significant deviation from these objectives raises the risk of decreased efficiency and productivity and adverse surgical outcomes. A warmer, more humid, and quieter environment is necessary for the patient. If these requirements are not met, the risk of surgical morbidity and mortality is increased. An important task for the surgical team is to find the correct balance between these 2 opposed requirements. Several of the components of the operating room environment, especially room temperature and airflow patterns, are easily manipulated by the members of the surgical team. In the following discussion, we will examine these elements to better understand the clinical ramifications of adjustments and accommodations that are frequently made to meet the requirements of both the surgical staff and the patient.

  7. A Multi-Environment Thermal Control System With Freeze-Tolerant Radiator Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Future space exploration missions require advanced thermal control systems (TCS) to dissipate heat from spacecraft, rovers, or habitats to external environments. We...

  8. Integrated Environment Control and Long-Term Development

    Directory of Open Access Journals (Sweden)

    Elena Maria MINEA

    2002-06-01

    Full Text Available The issue of environment is an apparently easy-to-debate subject, but, in fact, it is a very complex and tender issue, concerning the whole mankind. The observation and the analysis of the environment carried out especially by scientists; as well as the environmental monitoring of its quality confers new dimensions to the problem, because man is now faced with a horrible scourge of his own creation: pollution. The purpose of durable development is to find the optimum measure among four systems: the economic, the technologic, the ambient and the human.

  9. Optimization of humidifying procedure in controlled environment for ...

    African Journals Online (AJOL)

    hp

    2016-11-09

    Nov 9, 2016 ... This study investigated mushroom cultivation in controlled indoor ... The total 261.8 kg mushroom was harvested from the controlled cultivation system, a fairly good ..... Computer and Computing Technologies in Agriculture VI.

  10. Managing empowerment and control in an intranet environment

    OpenAIRE

    Duane, A.; Finnegan, Jason

    2003-01-01

    An intranet increases in sophistication and complexity as it evolves. This evolution leads to an increasing need for control over the intranet. However, this is a contentious issue, as an intranet is deemed to be an empowering technology. Consequently, intranet control systems must balance empowerment and control so as not to negate each other. This paper investigates intranet control activities and their effect on users' perceptions of empowerment throughout the evolution of an intranet in H...

  11. High-tech controls for energy and environment. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Biondo, S.J. [ed.] [USDOE, Washington, DC (United States); Drummond, C.J. [ed.] [USDOE Pittsburgh Energy Technology Center, PA (United States)

    1995-05-01

    This document contains reports which were presented at a symposium for adaptive control systems. Topics were concerned with fuzzy logic, genetic algorithms, adaptive processes control, nonlinear component analysis, and processes control and efficiency applied to reducing nitrogen oxides emissions and to a column flotation unit. Individual reports (22 reports) are processed separately for the data bases.

  12. Constraint, Intelligence, and Control Hierarchy in Virtual Environments. Chapter 1

    Science.gov (United States)

    Sheridan, Thomas B.

    2007-01-01

    This paper seeks to deal directly with the question of what makes virtual actors and objects that are experienced in virtual environments seem real. (The term virtual reality, while more common in public usage, is an oxymoron; therefore virtual environment is the preferred term in this paper). Reality is difficult topic, treated for centuries in those sub-fields of philosophy called ontology- "of or relating to being or existence" and epistemology- "the study of the method and grounds of knowledge, especially with reference to its limits and validity" (both from Webster s, 1965). Advances in recent decades in the technologies of computers, sensors and graphics software have permitted human users to feel present or experience immersion in computer-generated virtual environments. This has motivated a keen interest in probing this phenomenon of presence and immersion not only philosophically but also psychologically and physiologically in terms of the parameters of the senses and sensory stimulation that correlate with the experience (Ellis, 1991). The pages of the journal Presence: Teleoperators and Virtual Environments have seen much discussion of what makes virtual environments seem real (see, e.g., Slater, 1999; Slater et al. 1994; Sheridan, 1992, 2000). Stephen Ellis, when organizing the meeting that motivated this paper, suggested to invited authors that "We may adopt as an organizing principle for the meeting that the genesis of apparently intelligent interaction arises from an upwelling of constraints determined by a hierarchy of lower levels of behavioral interaction. "My first reaction was "huh?" and my second was "yeah, that seems to make sense." Accordingly the paper seeks to explain from the author s viewpoint, why Ellis s hypothesis makes sense. What is the connection of "presence" or "immersion" of an observer in a virtual environment, to "constraints" and what types of constraints. What of "intelligent interaction," and is it the intelligence of the

  13. An Access Control and Trust Management Framework for Loosely-Coupled Multidomain Environments

    Science.gov (United States)

    Zhang, Yue

    2010-01-01

    Multidomain environments where multiple organizations interoperate with each other are becoming a reality as can be seen in emerging Internet-based enterprise applications. Access control to ensure secure interoperation in such an environment is a crucial challenge. A multidomain environment can be categorized as "tightly-coupled" and…

  14. Quality control of computational fluid dynamics in indoor environments

    DEFF Research Database (Denmark)

    Sørensen, Dan Nørtoft; Nielsen, P. V.

    2003-01-01

    Computational fluid dynamics (CFD) is used routinely to predict air movement and distributions of temperature and concentrations in indoor environments. Modelling and numerical errors are inherent in such studies and must be considered when the results are presented. Here, we discuss modelling as...... the quality of CFD calculations, as well as guidelines for the minimum information that should accompany all CFD-related publications to enable a scientific judgment of the quality of the study....

  15. REACTOR ANALYSIS AND VIRTUAL CONTROL ENVIRONMENT (RAVEN) FY12 REPORT

    Energy Technology Data Exchange (ETDEWEB)

    Cristian Rabiti; Andrea Alfonsi; Joshua Cogliati; Diego Mandelli; Robert Kinoshita

    2012-09-01

    RAVEN is a complex software tool that will have tasks spanning from being the RELAP-7 user interface, to using RELAP-7 to perform Risk Informed Safety Characterization (RISMC), and to controlling RELAP-7 calculation execution. The goal of this document is to: 1. Highlight the functional requirements of the different tasks of RAVEN 2. Identify shared functions that could be aggregate in modules so to obtain a minimal software redundancy and maximize software utilization. RAVEN is in fact a software framework that will allow exploiting the following functionalities: • Derive and actuate the control logic required to: o Simulate the plant control system o Simulate the operator (procedure guided) actions o Perform Monte Carlo sampling of random distributed events o Perform event three based analysis • Provide a GUI to: o Input a plant description to RELAP-7 (component, control variable, control parameters) o Concurrent monitoring of Control Parameters o Concurrent alteration of control parameters • Provide Post Processing data mining capability based on o Dimensionality reduction o Cardinality reduction In this document it will be shown how an appropriate mathematical formulation of the control logic and probabilistic analysis leads to have most of the software infrastructure leveraged between the two main tasks. Further, this document will go through the development accomplished this year, including simulation results, and priorities for the next years development

  16. IEPLC Framework, Automated Communication in a Heterogeneous Control System Environment

    CERN Document Server

    Locci, F

    2014-01-01

    In CERN accelerators control system several components are essential such as: Programmable Logic Controller (PLC), PCI Extensions for Instrumentation (PXI), and other micro-controller families. Together with their weaknesses and their strength points they typically present custom communication protocols and it is therefore difficult to federate them into the control system using a single communication strategy. Furthermore this dependency to the physical device interfaces and protocols makes most of the code not reusable and the replacement of old technology a difficult problem. The purpose of IEPLC ([1]) is to mitigate the communication issues given by this heterogeneity; it proposes a framework to define communication interfaces in a hardware independent manner. In addition it automatically generates all the resources needed on master side (typically represented by a FEC: Front-End Computer) and slave side (typically represented by the controller) to implement a common and generic Ethernet communication. Th...

  17. Bilateral Teleoperation Method Using an Autonomous Control Based on Information on Contact Environment

    Science.gov (United States)

    Taguchi, Keiichi; Ohnishi, Kouhei

    In procedures that involve remote control, such as remote surgery, it is necessary to operate a robot in a remote location in a sensitive environment; the treatment of internal organs is an example of such a procedure. In this paper, we propose a method for autonomous hazard avoidance control that is based on information on the contact environment. The proposed method involves the use of bilateral control. During safe operations, systems are controlled by bilateral control. During dangerous operations, a slave system is controlled autonomously so as to avoid dangerous operations. In order to determine the degree of operation risk, fuzzy set theory is applied to the force exerted on the environment. Further, variable compliance control based on the force exerted on the environment is utilized to avoid the risk. The effectiveness of the proposed method is confirmed by experimental results.

  18. Garment Selection for Cleanrooms and Controlled Environments for Spacecraft

    Science.gov (United States)

    1991-04-01

    seeks to quantify 0.5-jm and larger particles. The method utilizes a process similar to that used in a clothes dryer . Garments are tumbled inside a...drum rotating at 10 rpm, while the air over the tumbling garment is tested with an automatic optical or laser particl oWlrter of the type nor- mally...alkaline environment. Water temperature must be no higher than 55"C (130F) to avoid wrinkles in the garment. Washing shall be followed by tumble

  19. Controlled Environments Enable Adaptive Management in Aquatic Ecosystems Under Altered Environments

    Science.gov (United States)

    Bubenheim, David L.

    2016-01-01

    Ecosystems worldwide are impacted by altered environment conditions resulting from climate, drought, and land use changes. Gaps in the science knowledge base regarding plant community response to these novel and rapid changes limit both science understanding and management of ecosystems. We describe how CE Technologies have enabled the rapid supply of gap-filling science, development of ecosystem simulation models, and remote sensing assessment tools to provide science-informed, adaptive management methods in the impacted aquatic ecosystem of the California Sacramento-San Joaquin River Delta. The Delta is the hub for California's water, supplying Southern California agriculture and urban communities as well as the San Francisco Bay area. The changes in environmental conditions including temperature, light, and water quality and associated expansion of invasive aquatic plants negatively impact water distribution and ecology of the San Francisco Bay/Delta complex. CE technologies define changes in resource use efficiencies, photosynthetic productivity, evapotranspiration, phenology, reproductive strategies, and spectral reflectance modifications in native and invasive species in response to altered conditions. We will discuss how the CE technologies play an enabling role in filling knowledge gaps regarding plant response to altered environments, parameterization and validation of ecosystem models, development of satellite-based, remote sensing tools, and operational management strategies.

  20. Countering Terrorism Through Control of Pakistan’s Information Environment

    Science.gov (United States)

    2014-09-01

    116 6. Al Rashid Trust...xiv THIS PAGE INTENTIONALLY LEFT BLANK xv LIST OF ACRONYMS AND ABBREVIATIONS AEWC Airborne Early Warning and Control ART Al Rashid Trust ASWJ...Al Rashid Trust, and indirect ties with Al Qaeda and Jaish-e-Mohammed (JeM). It is also alleged that Bashiruddin Mahmood’s team was trying to develop

  1. Schoenfeld's problem solving theory in a student controlled learning environment

    NARCIS (Netherlands)

    Harskamp, E.; Suhre, C.

    2007-01-01

    This paper evaluates the effectiveness of a student controlled computer program for high school mathematics based on instruction principles derived from Schoenfeld's theory of problem solving. The computer program allows students to choose problems and to make use of hints during different episodes

  2. Schoenfeld's problem solving theory in a student controlled learning environment

    NARCIS (Netherlands)

    Harskamp, E.; Suhre, C.

    2007-01-01

    This paper evaluates the effectiveness of a student controlled computer program for high school mathematics based on instruction principles derived from Schoenfeld's theory of problem solving. The computer program allows students to choose problems and to make use of hints during different episodes

  3. Controlling malaria with indoor residual spraying in spatially heterogenous environments.

    Science.gov (United States)

    Al-Arydah, Mo'tassem; Smith, Robert

    2011-10-01

    Indoor residual spraying-spraying insecticide inside houses to kill mosquitoes-has been one of the most effective methods of disease control ever devised, being responsible for the near-eradication of malaria from the world in the third quarter of the twentieth century and saving tens of millions of lives. However, with malaria resurgence currently underway, it has received relatively little attention, been applied only in select physical locations and not always at regular intervals. We extend a time-dependent model of malaria spraying to include spatial heterogeneity and address the following research questions: 1. What are the effects of spraying in different geographical areas? 2. How do the results depend upon the regularity of spraying? 3. Can we alter our control strategies to account for asymmetric phenomena such as wind? We use impulsive partial differential equation models to derive thresholds for malaria control when spraying occurs uniformly, within an interior disc or under asymmetric advection effects. Spatial heterogeneity results in an increase in the necessary frequency of spraying, but control is still achievable.

  4. Optimal Control Policy for Environment withScience and Technology Stochastic Occur

    Institute of Scientific and Technical Information of China (English)

    MinggaoXue; ChulinLi; PuGong

    2004-01-01

    In this paper, the control policy for environment with two kinds of irreversibility, which work in opposite directions and uncertainty of cost is regarded as an investment decision. By using real-option theory, the paper presents the model of the optimal control policy for environment under the science and technology that can reduce environment pollution stochastic occur. The paper has discussed the effects of changes in the various parameters on the critical value at which the policy should be adopted. The results show thatthe optimal control policy is quite sensitive to the science and technology which can reduce environment pollution stochastic occur, pointing to the importance of carefully accounting for its impact in determining the control policy for environment.

  5. Feasibility of BCI Control in a Realistic Smart Home Environment

    Directory of Open Access Journals (Sweden)

    Nataliya Kosmyna

    2016-08-01

    Full Text Available Smart homes have been an active area of research, however despite considerable investment, they are not yet a reality for end-users. Moreover, there are still accessibility challenges for the elderly or the disabled, two of the main potential targets for home automation. In this exploratory study we design a control mechanism for smart homes based on Brain Computer Interfaces (BCI and apply it in the Domus smart home platform in order to evaluate the potential interest of users about BCIs at home. We enable users to control lighting, a TV set, a coffee machine and the shutters of the smart home. We evaluate the performance (accuracy, interaction time, usability and feasibility (USE questionnaire on 12 healthy subjects and 2 disabled subjects. We find that healthy subjects achieve 77% task accuracy. However, disabled subjects achieved a better accuracy (81% compared to 77%.

  6. Occupant Behaviour with regard to Control of the Indoor Environment

    DEFF Research Database (Denmark)

    Andersen, Rune Vinther

    on the behaviour of their occupants. As a consequence, there is a need to investigate occupants’ interactions with building controls, such as opening of windows, adjustments of heating set-points, use of solar shading, etc. Some models of occupants’ interactions with operable windows do exist, but these are based...... behaviour of occupants was found to have a substantial impact on the energy performance of a building. This becomes increasingly important in buildings designed using the adaptive model of thermal comfort, where occupants are encouraged to interact with building controls. It was found that determination...... of acceptable thermal conditions with the adaptive model may result in significant energy savings and at the same time will not have large consequences for the mental performance of the occupants. Large differences in the behaviour patterns of occupants were found between dwellings. The time of day had a great...

  7. Feasibility of BCI Control in a Realistic Smart Home Environment

    Science.gov (United States)

    Kosmyna, Nataliya; Tarpin-Bernard, Franck; Bonnefond, Nicolas; Rivet, Bertrand

    2016-01-01

    Smart homes have been an active area of research, however despite considerable investment, they are not yet a reality for end-users. Moreover, there are still accessibility challenges for the elderly or the disabled, two of the main potential targets for home automation. In this exploratory study we design a control mechanism for smart homes based on Brain Computer Interfaces (BCI) and apply it in the “Domus”1 smart home platform in order to evaluate the potential interest of users about BCIs at home. We enable users to control lighting, a TV set, a coffee machine and the shutters of the smart home. We evaluate the performance (accuracy, interaction time), usability and feasibility (USE questionnaire) on 12 healthy subjects and 2 disabled subjects. We find that healthy subjects achieve 77% task accuracy. However, disabled subjects achieved a better accuracy (81% compared to 77%). PMID:27616986

  8. Feasibility of BCI Control in a Realistic Smart Home Environment.

    Science.gov (United States)

    Kosmyna, Nataliya; Tarpin-Bernard, Franck; Bonnefond, Nicolas; Rivet, Bertrand

    2016-01-01

    Smart homes have been an active area of research, however despite considerable investment, they are not yet a reality for end-users. Moreover, there are still accessibility challenges for the elderly or the disabled, two of the main potential targets for home automation. In this exploratory study we design a control mechanism for smart homes based on Brain Computer Interfaces (BCI) and apply it in the "Domus" smart home platform in order to evaluate the potential interest of users about BCIs at home. We enable users to control lighting, a TV set, a coffee machine and the shutters of the smart home. We evaluate the performance (accuracy, interaction time), usability and feasibility (USE questionnaire) on 12 healthy subjects and 2 disabled subjects. We find that healthy subjects achieve 77% task accuracy. However, disabled subjects achieved a better accuracy (81% compared to 77%).

  9. Management of fluorescent lamps in controlled environment chambers

    Science.gov (United States)

    Romer, Mark

    1994-01-01

    Management of fluorescent lights is recommended to (1) maintain uniformity of light intensity over time and (2) permit reproducibility of lighting conditions during experimental replications. At the McGill Phytotron, the lighting intensity can be controlled to desired level because any individual pair of the 40 lamps in each chamber can be set to be 'on' at any particular time. A lamp canopy service history is maintained for each experiment permitting accurate replication of lighting conditions for subsequent replicate trials.

  10. Mobile monitoring and embedded control system for factory environment.

    Science.gov (United States)

    Lian, Kuang-Yow; Hsiao, Sung-Jung; Sung, Wen-Tsai

    2013-12-17

    This paper proposes a real-time method to carry out the monitoring of factory zone temperatures, humidity and air quality using smart phones. At the same time, the system detects possible flames, and analyzes and monitors electrical load. The monitoring also includes detecting the vibrations of operating machinery in the factory area. The research proposes using ZigBee and Wi-Fi protocol intelligent monitoring system integration within the entire plant framework. The sensors on the factory site deliver messages and real-time sensing data to an integrated embedded systems via the ZigBee protocol. The integrated embedded system is built by the open-source 32-bit ARM (Advanced RISC Machine) core Arduino Due module, where the network control codes are built in for the ARM chipset integrated controller. The intelligent integrated controller is able to instantly provide numerical analysis results according to the received data from the ZigBee sensors. The Android APP and web-based platform are used to show measurement results. The built-up system will transfer these results to a specified cloud device using the TCP/IP protocol. Finally, the Fast Fourier Transform (FFT) approach is used to analyze the power loads in the factory zones. Moreover, Near Field Communication (NFC) technology is used to carry out the actual electricity load experiments using smart phones.

  11. Mobile Monitoring and Embedded Control System for Factory Environment

    Directory of Open Access Journals (Sweden)

    Kuang-Yow Lian

    2013-12-01

    Full Text Available This paper proposes a real-time method to carry out the monitoring of factory zone temperatures, humidity and air quality using smart phones. At the same time, the system detects possible flames, and analyzes and monitors electrical load. The monitoring also includes detecting the vibrations of operating machinery in the factory area. The research proposes using ZigBee and Wi-Fi protocol intelligent monitoring system integration within the entire plant framework. The sensors on the factory site deliver messages and real-time sensing data to an integrated embedded systems via the ZigBee protocol. The integrated embedded system is built by the open-source 32-bit ARM (Advanced RISC Machine core Arduino Due module, where the network control codes are built in for the ARM chipset integrated controller. The intelligent integrated controller is able to instantly provide numerical analysis results according to the received data from the ZigBee sensors. The Android APP and web-based platform are used to show measurement results. The built-up system will transfer these results to a specified cloud device using the TCP/IP protocol. Finally, the Fast Fourier Transform (FFT approach is used to analyze the power loads in the factory zones. Moreover, Near Field Communication (NFC technology is used to carry out the actual electricity load experiments using smart phones.

  12. Biosynthesized silver nanoparticles to control fungal infections in indoor environments

    Science.gov (United States)

    Deyá, Cecilia; Bellotti, Natalia

    2017-06-01

    Fungi grow especially in dark and moist areas, deteriorating the indoor environment and causing infections that particularly affect immunosuppressed individuals. Antimicrobial coatings have as principal objective to prevent biofilm formation and infections by incorporation of bioactive additives. In this sense, metallic nanoparticles, such as silver, have proven to be active against different microorganisms specially bacteria. Biosynthesized method is a promising environmentally friendly option to obtain nanoparticles. The aim of this research was assess the employment of plants extracts of Aloysia triphylla (cedrón), Laurelia sempervirens (laurel) and Ruta chalepensis (ruda) to obtain silver nanoparticles to be used as an antimicrobial additive to a waterborne coating formulation. The products obtained were assessed against fungal isolates from biodeteriorated indoor coatings. The fungi were identified by conventional and molecular techniques as Chaetomium globosum and Alternaria alternate. The results revealed that the coating with silver nanoparticles obtained with L. sempervirens extract at 60 °C with a size of 9.8 nm was the most efficient against fungal biofilm development.

  13. Control Systems application in Java based Enterprise and Cloud Environments – A Survey

    Directory of Open Access Journals (Sweden)

    Ravi Kumar Gullapalli

    2011-08-01

    Full Text Available The classical feedback control systems has been a successful theory in many engineering applications like electrical power, process, and manufacturing industries. For more than a decade there is active research in exploring feedback control systems applications in computing and some of the results are applied to the commercial software products. There are good number of research review papers on this subject exist, giving high level overview, explaining specific applications like load balancing or CPU utilization power management in data centers. We observe that majority of the control system applications are in Web and Application Server environments. We attempt to discuss on how control systems is applied to Web and Application(JEE Servers that are deployed in Enterprise and cloud environments. Our paper presents this review with a specific emphasis on Java based Web, Application and Enterprise Server Bus environments. We conclude with the future reserach in applying control systems to Enterprise and Cloud environments.

  14. Payload analysis and control of manipulators for human interactive environments

    OpenAIRE

    Arango Castro, Jaime Enrique

    2014-01-01

    Esta tesis doctoral presenta los resultados de simulaciones numéricas y algunos análisis experimentales de tres aspectos principales: el modelamiento dinámico de manipuladores de múltiples grados de libertad (GdL) (n > 2 GdL), el cálculo de la capacidad dinámica de carga asociada al manejo de dicha carga, y el análisis y diseño de controladores no lineales incluyendo el Control Adaptativo por Desfalsificación (CAD). Se desarrollaron análisis de dos (2) casos de estudio: el SCORBOT ER V PLUS ...

  15. A Mixed-Reality Environment for Digital Control Systems

    OpenAIRE

    Heinz-Dietrich Wuttke

    2006-01-01

    Learning the design of control systems requires not only deep theoretical but also practical experience that can be get in laboratory work. Goal of the projects “JGIFT†and “FIPS†- created by members of the Institute of Theoretical and Technical Computer Science of the Technical University of Ilmenau - is to examine and implement new techniques for a development and training system based on Finite State Machines (FSM). In our contribution we would like to present means and ...

  16. Robot-Environment Interaction Control of a Flexible Joint Light Weight Robot Manipulator

    Directory of Open Access Journals (Sweden)

    Genliang Xiong

    2012-09-01

    Full Text Available This paper presents a weighted path planning approach for a light weight robot coming into compliant contact with the environment, as well as robot‐environment interaction enabled impedance control. Using a joint torque sensor, Cartesian impedance control is introduced to realize the manipulator compliance control. Then the weighted path planning approach is developed to detect the contact condition and to control the interaction. Experiments are carried out on a 5‐DOF light weight manipulator. The experimental results validate the developed control approach enhanced by the weighted path planning scheme.

  17. The national and international regulatory environment in tobacco control.

    Science.gov (United States)

    Warner, Kenneth E

    2015-07-09

    Despite their lethality, cigarettes are subject to little regulation that directly restricts their contents or their legality. This may change in the near future with the Framework Convention on Tobacco Control (FCTC), the world's first global health treaty, now in force, as well as developments in a few individual countries. Cigarettes are subject to a substantial number of country-specific regulations regarding their conditions of sale: their price (mostly through taxation), the places where they can be consumed (clean indoor air laws), who can smoke them (prohibitions on their use by or sales to minors), how they can be advertised or promoted (if at all), and how they must be packaged (minimum pack sizes, warning labels, plain packaging). Such policies constitute the core of successful tobacco control. The FCTC has been ratified by 180 countries representing 90% of the world's population. The FCTC requires compliance with numerous provisions relating to the kinds of regulations noted above. The treaty also mandates explicit attention to direct product regulation. Several countries have such authority, at least in limited forms. In the US, for example, the Food and Drug Administration (FDA) now has the legal authority to regulate tobacco products, including their contents. The possibility exists that, in the foreseeable future, a country will mandate product standards that will substantially reduce the appeal of cigarettes and other combusted tobacco products, which are by far the leading sources of the death and disease associated with tobacco.

  18. Information-educational environment with adaptive control of learning process

    Science.gov (United States)

    Modjaev, A. D.; Leonova, N. M.

    2017-01-01

    Recent years, a new scientific branch connected with the activities in social sphere management developing intensively and it is called "Social Cybernetics". In the framework of this scientific branch, theory and methods of management of social sphere are formed. Considerable attention is paid to the management, directly in real time. However, the decision of such management tasks is largely constrained by the lack of or insufficiently deep study of the relevant sections of the theory and methods of management. The article discusses the use of cybernetic principles in solving problems of control in social systems. Applying to educational activities a model of composite interrelated objects representing the behaviour of students at various stages of educational process is introduced. Statistical processing of experimental data obtained during the actual learning process is being done. If you increase the number of features used, additionally taking into account the degree and nature of variability of levels of current progress of students during various types of studies, new properties of students' grouping are discovered. L-clusters were identified, reflecting the behaviour of learners with similar characteristics during lectures. It was established that the characteristics of the clusters contain information about the dynamics of learners' behaviour, allowing them to be used in additional lessons. The ways of solving the problem of adaptive control based on the identified dynamic characteristics of the learners are planned.

  19. Mounting human entities to control and interact with networked ship entities in a virtual environment

    OpenAIRE

    Stewart, Bryan Christopher

    1996-01-01

    Approved for public release; distribution is unlimited This thesis research addresses the problem of mounting human entities to other non-human entities in the virtual environment. Previous human entities were exercised as individual entities in the virtual environment. Yet there are many applications (i.e. shipboard damage control, amphibious landings, helicopter vertical assaults) where human entities need to mount other vehicles within the virtual environment. The approach taken was to ...

  20. Controlling Risk Exposure in Periodic Environments: A Genetic Algorithm Approach

    CERN Document Server

    Navarro, Emeterio

    2007-01-01

    In this paper, we compare the performance of different agent's investment strategies in an investment scenario with periodic returns and different types and levels of noise. We consider an investment model, where an agent decides the percentage of budget to risk at each time step. Afterwards, agent's investment is evaluated in the market via a return on investment (RoI), which we assume is a stochastic process with unknown periodicities and different levels of noise. To control the risk exposure, we investigate approaches based on: technical analysis (Moving Least Squares, MLS), and evolutionary computation (Genetic Algorithms, GA). In our comparison, we also consider two reference strategies for zero-knowledge and complete-knowledge behaviors, respectively. In our approach, the performance of a strategy corresponds to the average budget that can be obtained with this strategy over a certain number of time steps. To this end, we perform some computer experiments, where for each strategy the budget obtained af...

  1. The programmable (logic) controller: Adapting in an environment of change

    Energy Technology Data Exchange (ETDEWEB)

    Levine, P.S. [ed.

    1995-03-01

    Reports of the imminent death of the PLC (programmable logic controller) were greatly exaggerated, to paraphrase Mark Twain. In fact, the PLC is not only alive and working worldwide in thousands of applications, but it is also integrating well with related technologies. Long-term survival is a larger question - probably unanswerable given the pace of technological change. However, a few questions arise about the PLC today and in the immediate future: (1) What`s happening with programming languages? (2) Will there continue to be a {open_quotes}blurring of the lines{close_quotes} between the PLC and other technologies, and what role will software play in this integration? (3) How will the PLC`s cost and size affect the market?

  2. A Mixed-Reality Environment for Digital Control Systems

    Directory of Open Access Journals (Sweden)

    Heinz-Dietrich Wuttke

    2006-04-01

    Full Text Available Learning the design of control systems requires not only deep theoretical but also practical experience that can be get in laboratory work. Goal of the projects “JGIFT” and “FIPS” - created by members of the Institute of Theoretical and Technical Computer Science of the Technical University of Ilmenau - is to examine and implement new techniques for a development and training system based on Finite State Machines (FSM. In our contribution we would like to present means and methods required for providing this tool set web wide for a large user base and independent from the operating system.

  3. Customizable software architectures in the accelerator control system environment

    CERN Document Server

    Mejuev, I; Kadokura, E

    2001-01-01

    Tailoring is further evolution of an application after deployment in order to adapt it to requirements that were not accounted for in the original design. End-user customization has been extensively researched in applied computer science from HCI and software engineering perspectives. Customization allows coping with flexibility requirements, decreasing maintenance and development costs of software products. In general, dynamic or diverse software requirements constitute the need for implementing end-user customization in computer systems. In accelerator physics research the factor of dynamic requirements is especially important, due to frequent software and hardware modifications resulting in correspondingly high upgrade and maintenance costs. We introduce the results of feasibility study on implementing end-user tailorability in the software for accelerator control system, considering the design and implementation of a distributed monitoring application for the 12 GeV KEK Proton Synchrotron as an example. T...

  4. Sustaining Teacher Control in a Blog-Based Personal Learning Environment

    Science.gov (United States)

    Tomberg, Vladimir; Laanpere, Mart; Ley, Tobias; Normak, Peeter

    2013-01-01

    Various tools and services based on Web 2.0 (mainly blogs, wikis, social networking tools) are increasingly used in formal education to create personal learning environments, providing self-directed learners with more freedom, choice, and control over their learning. In such distributed and personalized learning environments, the traditional role…

  5. Sole-Source Lighting for Controlled-Environment Agriculture

    Science.gov (United States)

    Mitchell.Cary; Stutte, Gary W.

    2015-01-01

    Since plants on Earth evolved under broad-spectrum solar radiation, anytime they are grown exclusively under electric lighting that does not contain all wavelengths in similar proportion to those in sunlight, plant appearance and size could be uniquely different. Nevertheless, plants have been grown for decades under fluorescent (FL) (1) + incandescent (IN) (2) lamps as a sole source of lighting (SSL), and researchers have become comfortable that, in certain proportions of FL + IN for a given species, plants can appear "normal" relative to their growth outdoors. The problem with using such traditional SSLs for commercial production typically is short lamp lifespans and not obtaining enough photosynthetically active radiation (PAR, 400-700 nm) when desired. These limitations led to supplementation of FL + IN lamp outputs with longer-lived, high-intensity discharge (HID) lamps in growth chambers (3). As researchers became comfortable that mixes of orange-biased high-pressure sodium (HPS) and blue-biased metal halide (MH) HIDs together also could give normal plant growth at higher intensities, growth chambers and phytotrons subsequently were equipped mainly with HID lamps, with their intense thermal output filtered out by ventilated light caps or thermal-controlled water barriers. For the most part, IN and HID lamps have found a home in commercial protected horticulture, usually for night-break photoperiod lighting (IN) or for seasonal supplemental lighting (mostly HPS) in greenhouses. However, lack of economically viable options for SSL have held back aspects of year-round indoor agriculture from taking off commercially.

  6. Controlled environment life support system: Growth studies with potatoes

    Science.gov (United States)

    Tibbitts, T. W.; Wheeler, R. M.

    1986-01-01

    Results of experiments conducted to maximize the productivity of potatoes grown under controlled environmental conditions are discussed. A variety of parameters is examined which affect potato growth, specifically, photoperiod, light intensity, temperature, nitrogen nutrition, carbon dioxide concentration and culture techniques. These experiments were conducted using five different cultivars, Russet Burbank, Norchip, Superior, Kennebec and Norland. To achieve high productivity, three specific objectives were explored: (1) to develop effective cultural procedures, (2) to determine the most effective photoperiod and (3) to develop a mist culture system. It is felt that the productivity obtained in this study is below the maximum that can be obtained. High irradiance levels coupled with tuber-promoting conditions such as cooler temperatures, increased CO2 levels and lowered nitrogen concentrations should allow increases in tuber production. Tuberization appears to be accelerated by short daylengths although final yields are not increased. Mist culture techniques have not yet produced fully developed tubers. The use of supporting media and alteration of the nitrogen content of the mist solution are being explored as a way to allow tubers to develop to maturity.

  7. Local Measurement of Fuel Energy Deposition and Heat Transfer Environment During Fuel Lifetime Using Controlled Calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Don W. Miller; Andrew Kauffmann; Eric Kreidler; Dongxu Li; Hanying Liu; Daniel Mills; Thomas D. Radcliff; Joseph Talnagi

    2001-12-31

    A comprehensive description of the accomplishments of the DOE grant titled, ''Local Measurement of Fuel Energy Deposition and Heat Transfer Environment During Fuel Lifetime using Controlled Calorimetry''.

  8. Motor Controller for Extreme Environments Based on SiGe Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed innovation is a motor-control subsystem capable of operation in extreme environments, including those to be encountered on the Moon and Mars....

  9. The User Experience: Developing an Integrated Photogrammetric Control Environment (IPCE) for Planetary Mapping

    Science.gov (United States)

    Edmundson, K. L.; Archinal, B. A.; Backer, J. C.; Barrett, J. M.; Becker, K. J.; Becker, T. L.; Bonn, J. P.; Cook, D. A.; Hahn, M. A.; Humphrey, I. R.; Lambright, S.; Lee, E. M.; Mapel, J. A.; Oyama, K. A.; Paquette, A. C.; Shepherd, M. R.; Sides, S. C.; Sucharski, T. L.; Weller, L. A.

    2017-06-01

    The USGS Astrogeology Science Center is developing in ISIS3 an interactive user interface that integrates all aspects of the photogrammetric control process in a single environment. Here we provide a progress update on this work.

  10. Growth of the coccolithophore Emiliania huxleyi in light- and nutrient-limited batch reactors: relevance for the BIOSOPE deep ecological niche of coccolithophores

    Science.gov (United States)

    Perrin, Laura; Probert, Ian; Langer, Gerald; Aloisi, Giovanni

    2016-11-01

    Coccolithophores are unicellular calcifying marine algae that play an important role in the oceanic carbon cycle via their cellular processes of photosynthesis (a CO2 sink) and calcification (a CO2 source). In contrast to the well-studied, surface-water coccolithophore blooms visible from satellites, the lower photic zone is a poorly known but potentially important ecological niche for coccolithophores in terms of primary production and carbon export to the deep ocean. In this study, the physiological responses of an Emiliania huxleyi strain to conditions simulating the deep niche in the oligotrophic gyres along the BIOSOPE transect in the South Pacific Gyre were investigated. We carried out batch culture experiments with an E. huxleyi strain isolated from the BIOSOPE transect, reproducing the in situ conditions of light and nutrient (nitrate and phosphate) limitation. By simulating coccolithophore growth using an internal stores (Droop) model, we were able to constrain fundamental physiological parameters for this E. huxleyi strain. We show that simple batch experiments, in conjunction with physiological modelling, can provide reliable estimates of fundamental physiological parameters for E. huxleyi that are usually obtained experimentally in more time-consuming and costly chemostat experiments. The combination of culture experiments, physiological modelling and in situ data from the BIOSOPE cruise show that E. huxleyi growth in the deep BIOSOPE niche is limited by availability of light and nitrate. This study contributes more widely to the understanding of E. huxleyi physiology and behaviour in a low-light and oligotrophic environment of the ocean.

  11. Mineralogical Controls on Carbon Cycling in a Floodplain Environment

    Science.gov (United States)

    Arora, B.; Dwivedi, D.; Steefel, C. I.; Spycher, N.; Fox, P. M.; Nico, P. S.

    2016-12-01

    -associated organic carbon as compared to non-NRZ locations. Results therefore suggest that soil mineralogy constitutes a dominant control over organic carbon stocks and residence times. A mechanistic representation of soil mineral-organic-microbe interactions is necessary to reproduce SOM profiles at the site.

  12. Empirical Modeling of Plant Gas Fluxes in Controlled Environments

    Science.gov (United States)

    Cornett, Jessie David

    1994-01-01

    As humans extend their reach beyond the earth, bioregenerative life support systems must replace the resupply and physical/chemical systems now used. The Controlled Ecological Life Support System (CELSS) will utilize plants to recycle the carbon dioxide (CO2) and excrement produced by humans and return oxygen (O2), purified water and food. CELSS design requires knowledge of gas flux levels for net photosynthesis (PS(sub n)), dark respiration (R(sub d)) and evapotranspiration (ET). Full season gas flux data regarding these processes for wheat (Triticum aestivum), soybean (Glycine max) and rice (Oryza sativa) from published sources were used to develop empirical models. Univariate models relating crop age (days after planting) and gas flux were fit by simple regression. Models are either high order (5th to 8th) or more complex polynomials whose curves describe crop development characteristics. The models provide good estimates of gas flux maxima, but are of limited utility. To broaden the applicability, data were transformed to dimensionless or correlation formats and, again, fit by regression. Polynomials, similar to those in the initial effort, were selected as the most appropriate models. These models indicate that, within a cultivar, gas flux patterns appear remarkably similar prior to maximum flux, but exhibit considerable variation beyond this point. This suggests that more broadly applicable models of plant gas flux are feasible, but univariate models defining gas flux as a function of crop age are too simplistic. Multivariate models using CO2 and crop age were fit for PS(sub n), and R(sub d) by multiple regression. In each case, the selected model is a subset of a full third order model with all possible interactions. These models are improvements over the univariate models because they incorporate more than the single factor, crop age, as the primary variable governing gas flux. They are still limited, however, by their reliance on the other environmental

  13. Human response to individually controlled micro environment generated with localized chilled beam

    DEFF Research Database (Denmark)

    Uth, Simon C.; Nygaard, Linette; Bolashikov, Zhecho Dimitrov;

    2014-01-01

    Indoor environment in a single-office room created by a localised chilled beam with individual control of the primary air flow was studied. Response of 24 human subjects when exposed to the environment generated by the chilled beam was collected via questionnaires under a 2-hour exposure including...... and local thermal sensation reported by the subjects with the two systems. Both systems were equally acceptable. At 26°C the individual control of the localised chilled beam lead to higher acceptability of the work environment. At 28°C the acceptability decreased with the two systems. It was not acceptable...

  14. Effect of Personal Control over Thermal Environment in a Laboratorium Setting

    DEFF Research Database (Denmark)

    Kulve, M. te; Boerstra, A. C.; Toftum, Jørn;

    was that human responses to a thermal indoor environment depend on the availability of control opportunities. This was tested in a field lab where subjects had a personal desk fan with a stepless controller at their workplace. Two conditions were tested: one (the first) with individual control and one without......, but with identical indoor climate exposure as recorded during the first session. During both experimental conditions, 23 subjects were exposed for 120 min to an operative temperature of 28 °C and they were provided with a personal desk fan. During the first exposure subjects were allowed to adjust air velocity (and...... therefore local thermal environment) at any moment. For each subject the adjustments were recorded. In the second experiment, subjects were exposed to identical indoor environment conditions as recorded during the first experiment, but without individual control of the desk fan (control knob was hidden...

  15. Fuzzy force control of constrained robot manipulators based on impedance model in an unknown environment

    Institute of Scientific and Technical Information of China (English)

    LIU Hongyi; WANG Lei; WANG Fei

    2007-01-01

    To precisely implement the force control of robot manipulators in an unknown environment,a control strategy based on fuzzy prediction of the reference trajectory in the impedance model is developed.The force tracking experiments are executed in an open-architecture control system with different tracking velocities,different desired forces,different contact stiffnesses and different surface figurations.The corresponding force control results are compared and analyzed.The influences of unknown parameters of the environment on the contact force are analyzed based on experimental data,and the tunings of predictive scale factors are illustrated.The experimental results show that the desired trajectory in the impedance model is predicted exactly and rapidly in the cases that the contact surface is unknown,the contact stiffness changes,and the fuzzy force control algorithm has high adaptability to the unknown environment.

  16. Autonomy supported, learner-controlled or system-controlled learning in hypermedia environments and the influence of academic self-regulation style

    NARCIS (Netherlands)

    Gorissen, Chantal; Kester, Liesbeth; Brand-Gruwel, Saskia; Martens, Rob

    2012-01-01

    Gorissen, C. J. J., Kester, L., Brand-Gruwel, S., & Martens, R. (in press). Autonomy supportive, learner-controlled or system-controlled learning in hypermedia environments and the influence of academic self-regulation style. Interactive Learning Environments.

  17. Differential nutrient limitation of soil microbial biomass and metabolic quotients (qCO2): is there a biological stoichiometry of soil microbes?

    Science.gov (United States)

    Hartman, Wyatt H; Richardson, Curtis J

    2013-01-01

    Variation in microbial metabolism poses one of the greatest current uncertainties in models of global carbon cycling, and is particularly poorly understood in soils. Biological Stoichiometry theory describes biochemical mechanisms linking metabolic rates with variation in the elemental composition of cells and organisms, and has been widely observed in animals, plants, and plankton. However, this theory has not been widely tested in microbes, which are considered to have fixed ratios of major elements in soils. To determine whether Biological Stoichiometry underlies patterns of soil microbial metabolism, we compiled published data on microbial biomass carbon (C), nitrogen (N), and phosphorus (P) pools in soils spanning the global range of climate, vegetation, and land use types. We compared element ratios in microbial biomass pools to the metabolic quotient qCO2 (respiration per unit biomass), where soil C mineralization was simultaneously measured in controlled incubations. Although microbial C, N, and P stoichiometry appeared to follow somewhat constrained allometric relationships at the global scale, we found significant variation in the C∶N∶P ratios of soil microbes across land use and habitat types, and size-dependent scaling of microbial C∶N and C∶P (but not N∶P) ratios. Microbial stoichiometry and metabolic quotients were also weakly correlated as suggested by Biological Stoichiometry theory. Importantly, we found that while soil microbial biomass appeared constrained by soil N availability, microbial metabolic rates (qCO2) were most strongly associated with inorganic P availability. Our findings appear consistent with the model of cellular metabolism described by Biological Stoichiometry theory, where biomass is limited by N needed to build proteins, but rates of protein synthesis are limited by the high P demands of ribosomes. Incorporation of these physiological processes may improve models of carbon cycling and understanding of the effects of

  18. Multifrequency permittivity measurements enable on-line monitoring of changes in intracellular conductivity due to nutrient limitations during batch cultivations of CHO cells.

    Science.gov (United States)

    Ansorge, Sven; Esteban, Geoffrey; Schmid, Georg

    2010-01-01

    Lab and pilot scale batch cultivations of a CHO K1/dhfr(-) host cell line were conducted to evaluate on-line multifrequency permittivity measurements as a process monitoring tool. The beta-dispersion parameters such as the characteristic frequency (f(C)) and the permittivity increment (Deltaepsilon(max)) were calculated on-line from the permittivity spectra. The dual-frequency permittivity signal correlated well with the off-line measured biovolume and the viable cell density. A significant drop in permittivity was monitored at the transition from exponential growth to a phase with reduced growth rate. Although not reflected in off-line biovolume measurements, this decrease coincided with a drop in OUR and was probably caused by the depletion of glutamine and a metabolic shift occurring at the same time. Sudden changes in cell density, cell size, viability, capacitance per membrane area (C(M)), and effects caused by medium conductivity (sigma(m)) could be excluded as reasons for the decrease in permittivity. After analysis of the process data, a drop in f(C) as a result of a fall in intracellular conductivity (sigma(i)) was identified as responsible for the observed changes in the dual-frequency permittivity signal. It is hypothesized that the beta-dispersion parameter f(C) is indicative of changes in nutrient availability that have an impact on intracellular conductivity sigma(i). On-line permittivity measurements consequently not only reflect the biovolume but also the physiological state of mammalian cell cultures. These findings should pave the way for a better understanding of the intracellular state of cells and render permittivity measurements an important tool in process development and control.

  19. Nutrient limitation in three lowland tropical forests in southern China receiving high nitrogen deposition: insights from fine root responses to nutrient additions.

    Science.gov (United States)

    Zhu, Feifei; Yoh, Muneoki; Gilliam, Frank S; Lu, Xiankai; Mo, Jiangming

    2013-01-01

    Elevated nitrogen (N) deposition to tropical forests may accelerate ecosystem phosphorus (P) limitation. This study examined responses of fine root biomass, nutrient concentrations, and acid phosphatase activity (APA) of bulk soil to five years of N and P additions in one old-growth and two younger lowland tropical forests in southern China. The old-growth forest had higher N capital than the two younger forests from long-term N accumulation. From February 2007 to July 2012, four experimental treatments were established at the following levels: Control, N-addition (150 kg N ha(-1) yr(-1)), P-addition (150 kg P ha(-1) yr(-1)) and N+P-addition (150 kg N ha(-1) yr(-1) plus 150 kg P ha(-1) yr(-1)). We hypothesized that fine root growth in the N-rich old-growth forest would be limited by P availability, and in the two younger forests would primarily respond to N additions due to large plant N demand. Results showed that five years of N addition significantly decreased live fine root biomass only in the old-growth forest (by 31%), but significantly elevated dead fine root biomass in all the three forests (by 64% to 101%), causing decreased live fine root proportion in the old-growth and the pine forests. P addition significantly increased live fine root biomass in all three forests (by 20% to 76%). The combined N and P treatment significantly increased live fine root biomass in the two younger forests but not in the old-growth forest. These results suggest that fine root growth in all three study forests appeared to be P-limited. This was further confirmed by current status of fine root N:P ratios, APA in bulk soil, and their responses to N and P treatments. Moreover, N addition significantly increased APA only in the old-growth forest, consistent with the conclusion that the old-growth forest was more P-limited than the younger forests.

  20. Nutrient limitation in three lowland tropical forests in southern China receiving high nitrogen deposition: insights from fine root responses to nutrient additions.

    Directory of Open Access Journals (Sweden)

    Feifei Zhu

    Full Text Available Elevated nitrogen (N deposition to tropical forests may accelerate ecosystem phosphorus (P limitation. This study examined responses of fine root biomass, nutrient concentrations, and acid phosphatase activity (APA of bulk soil to five years of N and P additions in one old-growth and two younger lowland tropical forests in southern China. The old-growth forest had higher N capital than the two younger forests from long-term N accumulation. From February 2007 to July 2012, four experimental treatments were established at the following levels: Control, N-addition (150 kg N ha(-1 yr(-1, P-addition (150 kg P ha(-1 yr(-1 and N+P-addition (150 kg N ha(-1 yr(-1 plus 150 kg P ha(-1 yr(-1. We hypothesized that fine root growth in the N-rich old-growth forest would be limited by P availability, and in the two younger forests would primarily respond to N additions due to large plant N demand. Results showed that five years of N addition significantly decreased live fine root biomass only in the old-growth forest (by 31%, but significantly elevated dead fine root biomass in all the three forests (by 64% to 101%, causing decreased live fine root proportion in the old-growth and the pine forests. P addition significantly increased live fine root biomass in all three forests (by 20% to 76%. The combined N and P treatment significantly increased live fine root biomass in the two younger forests but not in the old-growth forest. These results suggest that fine root growth in all three study forests appeared to be P-limited. This was further confirmed by current status of fine root N:P ratios, APA in bulk soil, and their responses to N and P treatments. Moreover, N addition significantly increased APA only in the old-growth forest, consistent with the conclusion that the old-growth forest was more P-limited than the younger forests.

  1. Formation Control of Mobile Agents with Second-order Nonlinear Dynamics in Unknown Environments Containing Obstacles

    NARCIS (Netherlands)

    Huang, Jie; Cao, Ming; Zhou, Ning

    2016-01-01

    This paper investigates the formation control problem of multiple mobile agents with second-order nonlinear dynamics in complex environments containing multiple obstacles. By employing the null-space-based behavioral (NSB) control architecture, a novel fast terminal sliding mode based adaptive contr

  2. Development and Validation of a Controlled Virtual Environment for Guidance, Navigation and Control of Quadrotor UAV

    Science.gov (United States)

    2013-09-01

    solving optimal control problems , a...approach for solving optimal control problems was that of indirect methods. However, the disadvantage associated with indirect methods is that the boundary...the adjoint equations, control equations and all the transversality conditions explicitly. Thus, solving optimal control problems using

  3. Can personal control over the physical environment ease distractions in office workplaces?

    Science.gov (United States)

    Lee, So Young; Brand, J L

    2010-03-01

    The purpose of this study was to investigate whether perception of control over aspects of the physical environment reduces the previously documented negative effects of distraction in office workplaces on perceived job performance. This study analysed 384 questionnaires collected from employees in the corporate offices of three manufacturing companies in Michigan, USA. The role of a sense of personal control over physical environment features as a mediating influence between work attitudes and work outcomes was explored using structural equations modelling. The results showed that workers' sense of control over physical aspects of their work environment mediated the relationship between perceived distractions and perceived job performance. These results suggest that increasing perceptions of personal control over features of the physical work environment may serve to link work attitudes and work outcomes. STATEMENT OF RELEVANCE: Open-plan offices are common throughout the world, making this study relevant for researchers and practitioners alike. These results suggest that if employees can adjust aspects of their office work environment, this may increase their sense of personal control, reducing the effects of distractions, a frequent complaint in open offices.

  4. Evaluation of ULV and Thermal Fog Mosquito Control Applications in Temperate and Desert Environments

    Science.gov (United States)

    2010-01-01

    current control strategies (Linthicum et al. 2007, Cope et al. 2008, Dalton 2008). A survey of the literature between 1940 and 2009 reveals an...applications to control Culex and Aedes adults in temperate and desert environments. Multiple factors including envi- ronmental conditions have a...Chanthon K. 1976. The control of field populations of Aedes aegypti by malathion, fenitrothion, bioresmethrin and pyre- thrum ULV ground aerosols, and by

  5. A monitor for the laboratory evaluation of control integrity in digital control systems operating in harsh electromagnetic environments

    Science.gov (United States)

    Belcastro, Celeste M.; Fischl, Robert; Kam, Moshe

    1992-01-01

    This paper presents a strategy for dynamically monitoring digital controllers in the laboratory for susceptibility to electromagnetic disturbances that compromise control integrity. The integrity of digital control systems operating in harsh electromagnetic environments can be compromised by upsets caused by induced transient electrical signals. Digital system upset is a functional error mode that involves no component damage, can occur simultaneously in all channels of a redundant control computer, and is software dependent. The motivation for this work is the need to develop tools and techniques that can be used in the laboratory to validate and/or certify critical aircraft controllers operating in electromagnetically adverse environments that result from lightning, high-intensity radiated fields (HIRF), and nuclear electromagnetic pulses (NEMP). The detection strategy presented in this paper provides dynamic monitoring of a given control computer for degraded functional integrity resulting from redundancy management errors, control calculation errors, and control correctness/effectiveness errors. In particular, this paper discusses the use of Kalman filtering, data fusion, and statistical decision theory in monitoring a given digital controller for control calculation errors.

  6. Controlling the quantum-memory-assisted entropic uncertainty relation by quantum-jump-based feedback control in dissipative environments

    Science.gov (United States)

    Yu, Min; Fang, Mao-Fa

    2017-09-01

    The dynamic properties of the quantum-memory-assisted entropic uncertainty relation for a system comprised of a qubit to be measured and a memory qubit are investigated. We explore the behaviors of the entropic uncertainty and its lower bound in three different cases: Only one of the two qubits interacts with an external environment and subjects to quantum-jump-based feedback control, or both of the two qubits independently experience their own environments and local quantum-jump-based feedback control. Our results reveal that the quantum-jump-based feedback control with an appropriate feedback parameter can reduce the entropic uncertainty and its lower bound, and for the three different scenarios, the reduction in the uncertainty relates to different physical quantities. Besides, we find out that the quantum-jump-based feedback control not only can remarkably decrease the entropic uncertainty, but also can make the uncertainty reach its lower bound where the dynamical map becomes unital.

  7. The influence of the aquatic environment on the control of postural sway.

    Science.gov (United States)

    Marinho-Buzelli, Andresa R; Rouhani, Hossein; Masani, Kei; Verrier, Mary C; Popovic, Milos R

    2017-01-01

    Balance training in the aquatic environment is often used in rehabilitation practice to improve static and dynamic balance. Although aquatic therapy is widely used in clinical practice, we still lack evidence on how immersion in water actually impacts postural control. We examined how postural sway measured using centre of pressure and trunk acceleration parameters are influenced by the aquatic environment along with the effects of visual information. Our results suggest that the aquatic environment increases postural instability, measured by the centre of pressure parameters in the time-domain. The mean velocity and area were more significantly affected when individuals stood with eyes closed in the aquatic environment. In addition, a more forward posture was assumed in water with eyes closed in comparison to standing on land. In water, the low frequencies of sway were more dominant compared to standing on dry land. Trunk acceleration differed in water and dry land only for the larger upper trunk acceleration in mediolateral direction during standing in water. This finding shows that the study participants potentially resorted to using their upper trunk to compensate for postural instability in mediolateral direction. Only the lower trunk seemed to change acceleration pattern in anteroposterior and mediolateral directions when the eyes were closed, and it did so depending on the environment conditions. The increased postural instability and the change in postural control strategies that the aquatic environment offers may be a beneficial stimulus for improving balance control.

  8. Research on framework for formation control of multiple underwater robots in a dynamic environment

    Institute of Scientific and Technical Information of China (English)

    MENG Xian-song; XU Hong-gen; ZHANG Ming-jun

    2004-01-01

    In this paper a practical framework is proposed to keep formation control of multiple underwater robots in a dynamic environment. The approach is a viable solution to solve formation problem. The approach allows online planning of the formation paths using a Dijkstra's search algorithm based on the current sensor data. The formation is allowed to be dynamically changed in order to avoid obstacles in the environment. A controller is designed to keep the robots in their planned trajectories. It is shown that the approach is effec In this paper a practical framework is proposed to keep formation control of multiple underwater robots in a dynamic environment. The approach is a viable solution to solve formation problem.

  9. SOLERAS - Solar Controlled Environment Agriculture Project. Final report, Volume 1. Project summary

    Energy Technology Data Exchange (ETDEWEB)

    1985-12-30

    A summary of the Solar Controlled Environment Agriculture Project is presented. The design of the greenhouses include transparent double pane glass roof with channels for fluid between the panes, inner pane tinted and double pane extruded acrylic aluminized mylar shade and diffuser. Solar energy technologies provide power for water desalination, for pumping irrigation water, and for cooling and heating the controlled environment space so that crops can grow in arid lands. The project is a joint effort between the United States and Saudi Arabia. (BCS)

  10. Eye-based Direct Interaction for Environmental Control in Heterogeneous Smart Environments

    Science.gov (United States)

    Corno, Fulvio; Gale, Alastair; Majaranta, Päivi; Räihä, Kari-Jouko

    environmental control is the control, operation, and monitoring of an environment via intermediary technology such as a computer. Typically this means control of a domestic home.Within the scope of COGAIN, this environmental control concerns the control of the personal environment of a person (with or without a disability). This defines environmental control as the control of a home or domestic setting and those objects that are within that setting. Thus, we may say that environmental control systems enable anyone to operate a wide range of domestic appliances and other vital functions in the home by remote control. In recent years the problem of self-sufficiency for older people and people with a disability has attracted increasing attention and resources. The search for new solutions that can guarantee greater autonomy and a better quality of life has begun to exploit easily available state-of-the-art technology. Personal environmental control can be considered to be a comprehensive and effective aid, adaptable to the functional possibilities of the user and to their desired actions.

  11. Design and Comparative Study of Three Photovoltaic Battery Charge Control Algorithms in MATLAB/SIMULINK Environment

    Directory of Open Access Journals (Sweden)

    Ankur Bhattacharjee

    2012-09-01

    Full Text Available This paper contains the design of a three stage solar battery charge controller and a comparative study of this charge control technique with three conventional solar battery charge control techniques such as 1. Constant Current (CC charging, 2. Two stage constant current constant voltage (CC-CV charging technique. The analysis and the comparative study of the aforesaid charging techniques are done in MATLAB/SIMULINK environment. Here the practical data used to simulate the charge control algorithms are based on a 12Volts 7Ah Sealed lead acid battery.

  12. Development of a Novel Motor Imagery Control Technique and Application in a Gaming Environment

    Science.gov (United States)

    Xue, Tao

    2017-01-01

    We present a methodology for a hybrid brain-computer interface (BCI) system, with the recognition of motor imagery (MI) based on EEG and blink EOG signals. We tested the BCI system in a 3D Tetris and an analogous 2D game playing environment. To enhance player's BCI control ability, the study focused on feature extraction from EEG and control strategy supporting Game-BCI system operation. We compared the numerical differences between spatial features extracted with common spatial pattern (CSP) and the proposed multifeature extraction. To demonstrate the effectiveness of 3D game environment at enhancing player's event-related desynchronization (ERD) and event-related synchronization (ERS) production ability, we set the 2D Screen Game as the comparison experiment. According to a series of statistical results, the group performing MI in the 3D Tetris environment showed more significant improvements in generating MI-associated ERD/ERS. Analysis results of game-score indicated that the players' scores presented an obvious uptrend in 3D Tetris environment but did not show an obvious downward trend in 2D Screen Game. It suggested that the immersive and rich-control environment for MI would improve the associated mental imagery and enhance MI-based BCI skills. PMID:28572817

  13. Sense of control under uncertainty depends on people's childhood environment: a life history theory approach.

    Science.gov (United States)

    Mittal, Chiraag; Griskevicius, Vladas

    2014-10-01

    Past research found that environmental uncertainty leads people to behave differently depending on their childhood environment. For example, economic uncertainty leads people from poor childhoods to become more impulsive while leading people from wealthy childhoods to become less impulsive. Drawing on life history theory, we examine the psychological mechanism driving such diverging responses to uncertainty. Five experiments show that uncertainty alters people's sense of control over the environment. Exposure to uncertainty led people from poorer childhoods to have a significantly lower sense of control than those from wealthier childhoods. In addition, perceptions of control statistically mediated the effect of uncertainty on impulsive behavior. These studies contribute by demonstrating that sense of control is a psychological driver of behaviors associated with fast and slow life history strategies. We discuss the implications of this for theory and future research, including that environmental uncertainty might lead people who grew up poor to quit challenging tasks sooner than people who grew up wealthy.

  14. Influence of heat cost allocation on occupants' control of indoor environment in 56 apartments

    DEFF Research Database (Denmark)

    Andersen, Søren; Andersen, Rune Korsholm; Olesen, Bjarne W.

    2016-01-01

    by comparing indoor environmental measurements between two buildings: one with collective payment and one with individual payment. The measurements were collected at 5 min intervals at a central location in each of 56 apartments in Copenhagen, Denmark over a period of two months. Questionnaires and semi......-structured interviews showed a strong influence of the heat cost allocation plan on the occupants' control strategies. Occupants whose heating bills were based on floor area focused on a healthy and comfortable indoor environment. Occupants whose heating bills were based on meter readings focused on energy conservation...... of this paper was to study the indoor environment in buildings with collective and individual heat cost allocation plans, to investigate how the heat cost allocation influenced occupant behaviour and how occupants controlled the indoor environment. The effects of the heat cost allocation type were studied...

  15. Primitive environment control for preservation of pit relics in archeology museums of China.

    Science.gov (United States)

    Gu, Zhaolin; Luo, Xilian; Meng, Xiangzhao; Wang, Zanshe; Ma, Tao; Yu, Chuck; Rong, Bo; Li, Ku; Li, Wenwu; Tan, Ying

    2013-02-01

    Immovable historical relics in some archeology museums of China suffer deterioration due to their improper preservation environment. The existing environmental control systems used in archeology museums are often designed for the amenities of visitors, and these manipulated environments are often inappropriate for the conservation of abiotic relics. This paper points out that the large open space of the existing archeology museum could be a cause of deterioration of the relics from the point of view of indoor air convective flow. The paper illustrates the need to introduce a local pit environmental control, which could reintegrate a pit primitive environment for the preservation of the historical relics by using an air curtain system, orientated to isolate the unearthed relics, semiexposed in pits to the large gallery open space of the exhibition hall.

  16. Preparing Content-Rich Learning Environments with VPython and Excel, Controlled by Visual Basic for Applications

    Science.gov (United States)

    Prayaga, Chandra

    2008-01-01

    A simple interface between VPython and Microsoft (MS) Office products such as Word and Excel, controlled by Visual Basic for Applications, is described. The interface allows the preparation of content-rich, interactive learning environments by taking advantage of the three-dimensional (3D) visualization capabilities of VPython and the GUI…

  17. INVERSE PROBLEM METHOD FOR WATER ENVIRONMENT TOTAL CAPACITY CONTROL OF A TIDAL RIVER

    Institute of Scientific and Technical Information of China (English)

    WANG Dao-zeng; ZHAO Yu-feng; LIN Wei-qing

    2005-01-01

    In this paper, an improved method for water environment total capacity control of tidal rivers was presented. The maximal capacity of point pollution sources for the Huangpu River was computed by this method, and the result was compared with the practically observed data. The numerical result shows that the method is effective and efficient.

  18. Instructional Control of Cognitive Load in the Design of Complex Learning Environments

    NARCIS (Netherlands)

    Kester, Liesbeth; Paas, Fred; Van Merriënboer, Jeroen

    2010-01-01

    Kester, L., Paas, F., & Van Merriënboer, J. J. G. (2010). Instructional control of cognitive load in the design of complex learning environments. In J. L. Plass, R. Moreno, & Roland Brünken (Eds.), Cognitive Load Theory (pp. 109-130). New York: Cambridge University Press.

  19. A Survey of Security Tools for the Industrial Control System Environment

    Energy Technology Data Exchange (ETDEWEB)

    Hurd, Carl M. [Idaho National Lab. (INL), Idaho Falls, ID (United States); McCarty, Michael V. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2017-06-12

    This report details the results of a survey conducted by Idaho National Laboratory (INL) to identify existing tools which could be used to prevent, detect, mitigate, or investigate a cyber-attack in an industrial control system (ICS) environment. This report compiles a list of potentially applicable tools and shows the coverage of the tools in an ICS architecture.

  20. Amplitude Test for Input Devices for System Control in Immersive Virtual Environment

    DEFF Research Database (Denmark)

    Stenholt, Rasmus; Thornemann Hansen, Nina; Hald, Kasper

    2014-01-01

    In this study, the amplitudes best suited to compare four input devices are examined in the context of a pointer-based system control interface for immersive virtual environments. The interfaces are based on a pen and tablet, a touch tablet, hand-tracking using Kinect and a Wii Nunchuk analog stick...

  1. Policy Based Access Control in Dynamic Grid-based Collaborative Environment

    NARCIS (Netherlands)

    Y. Demchenko; L. Gommans; A. Tokmakoff; R. van Buuren

    2006-01-01

    This paper describes the design and development of a flexible, customer-driven, security infrastructure for Gridbased Collaborative Environments. The paper proposes further development of the access control model built around a service or resource provisioning agreement (e.g., an experiment or proje

  2. Sequential tests for gene–environment interactions in matched case–control studies

    NARCIS (Netherlands)

    Tweel, I. van der; Schipper, M.E.I.

    2004-01-01

    The sample size necessary to detect a significant gene × environment interaction in an observational study can be large. For reasons of cost-effectiveness and efficient use of available biological samples we investigated the properties of sequential designs in matched case–control studies to test fo

  3. An agile planning and control framework for customer-order driven discrete parts manufacturing environments

    NARCIS (Netherlands)

    Assen, van M.F.; Hans, E.W.; Velde, van de S.L.

    2000-01-01

    In this paper, we present a planning and control framework for manufacture-to-order environments that enables and supports agile-based discrete parts manufacturing. The characteristic elements of our framework are that it is decentralized, logistics and business oriented, and that it recognizes that

  4. Beyond the Personal Learning Environment: Attachment and Control in the Classroom of the Future

    Science.gov (United States)

    Johnson, Mark William; Sherlock, David

    2014-01-01

    The Personal Learning Environment (PLE) has been presented in a number of guises over a period of 10 years as an intervention which seeks the reorganisation of educational technology through shifting the "locus of control" of technology towards the learner. In the intervening period to the present, a number of initiatives have attempted…

  5. Beyond the Personal Learning Environment: Attachment and Control in the Classroom of the Future

    Science.gov (United States)

    Johnson, Mark William; Sherlock, David

    2014-01-01

    The Personal Learning Environment (PLE) has been presented in a number of guises over a period of 10 years as an intervention which seeks the reorganisation of educational technology through shifting the "locus of control" of technology towards the learner. In the intervening period to the present, a number of initiatives have attempted…

  6. The Performance Implications of Fit among Environment, Strategy, Structure, Control System and Social Performance

    Directory of Open Access Journals (Sweden)

    Hasan Fauzi

    2009-12-01

    domain will be contingent upon strategic behaviors, which are behaviors of members in an organization. The paper integrates the contextual variables including business environment, strategy, organization structure, and control system with corporate performance by using corporate social performance as moderating variable by means of a recent literatures study from strategic management and accounting field.

  7. Solar energy controlled-environment agriculture in the United States and in Saudi Arabia

    Science.gov (United States)

    Luft, W.; Froechtenigt, J.

    1981-11-01

    Greenhouse designs proposed for use in hot climates to reduce the temperature by essentially passive means are illustrated. The project plans of the SOLERAS, solar powered, controlled environment agriculture are outlined. The water desalination technology being evaluated is reverse osmosis. The solar collection technologies include flat plate thermal collectors, solar ponds, photovoltaics and wind turbines.

  8. 78 FR 56541 - Concept Release on Risk Controls and System Safeguards for Automated Trading Environments

    Science.gov (United States)

    2013-09-12

    ... September 12, 2013 Part IV Commodity Futures Trading Commission 17 CFR Chapter I Concept Release on Risk Controls and System Safeguards for Automated Trading Environments; Proposed Rule #0;#0;Federal Register / Vol. 78 , No. 177 / Thursday, September 12, 2013 / Proposed Rules#0;#0; ] COMMODITY FUTURES...

  9. Demographic parameters of individual E.coli within and among controlled environment

    DEFF Research Database (Denmark)

    Jouvet, Lionel; Steiner, Ulrich

    2014-01-01

    . This can be achieved by working on isogenic populations under controlled environments. We use a microfluidic device to limit stochastic processes to their molecular components. The high throughput microfluidic device traps thousands of individual E. coli cells and tracks them over their lifespan...

  10. Rational spatio-temporal strategies for controlling a Chagas disease vector in urban environments.

    Science.gov (United States)

    Levy, Michael Z; Malaga Chavez, Fernando S; Cornejo Del Carpio, Juan G; Vilhena, Daril A; McKenzie, F Ellis; Plotkin, Joshua B

    2010-07-06

    The rational design of interventions is critical to controlling communicable diseases, especially in urban environments. In the case of the Chagas disease vector Triatoma infestans, successful control is stymied by the return of the insect after the effectiveness of the insecticide wanes. Here, we adapt a genetic algorithm, originally developed for the travelling salesman problem, to improve the spatio-temporal design of insecticide campaigns against T. infestans, in a complex urban environment. We find a strategy that reduces the expected instances of vector return 34-fold compared with the current strategy of sequential insecticide application to spatially contiguous communities. The relative success of alternative control strategies depends upon the duration of the effectiveness of the insecticide, and it shows chaotic fluctuations in response to unforeseen delays in a control campaign. We use simplified models to analyse the outcomes of qualitatively different spatio-temporal strategies. Our results provide a detailed procedure to improve control efforts for an urban Chagas disease vector, as well as general guidelines for improving the design of interventions against other disease agents in complex environments.

  11. MAPPING GNSS RESTRICTED ENVIRONMENTS WITH A DRONE TANDEM AND INDIRECT POSITION CONTROL

    Directory of Open Access Journals (Sweden)

    E. Cledat

    2017-08-01

    Full Text Available The problem of autonomously mapping highly cluttered environments, such as urban and natural canyons, is intractable with the current UAV technology. The reason lies in the absence or unreliability of GNSS signals due to partial sky occlusion or multi-path effects. High quality carrier-phase observations are also required in efficient mapping paradigms, such as Assisted Aerial Triangulation, to achieve high ground accuracy without the need of dense networks of ground control points. In this work we consider a drone tandem in which the first drone flies outside the canyon, where GNSS constellation is ideal, visually tracks the second drone and provides an indirect position control for it. This enables both autonomous guidance and accurate mapping of GNSS restricted environments without the need of ground control points. We address the technical feasibility of this concept considering preliminary real-world experiments in comparable conditions and we perform a mapping accuracy prediction based on a simulation scenario.

  12. Learning-based force servoing control of a robot with vision in an unknown environment

    Institute of Scientific and Technical Information of China (English)

    肖南峰

    2004-01-01

    A learning-based control approach is presented for force servoing of a robot with vision in an unknown environment. Firstly, mapping relationships between image features of the servoing object and the joint angles of the robot are derived and learned by a neural network. Secondly, a learning controller based on the neural network is designed for the robot to trace the object. Thirdly, a discrete time impedance control law is obtained for the force servoing of the robot,the on-line learning algorithms for three neural networks are developed to adjust the impedance parameters of the robot in the unknown environment. Lastly, wiping experiments are carried out by using a 6 DOF industrial robot with a CCD camera and a force/torque sensor in its end effector, and the experimental results confirm the effectiveness of the approach.

  13. Adaptive randomized algorithms for analysis and design of control systems under uncertain environments

    Science.gov (United States)

    Chen, Xinjia

    2015-05-01

    We consider the general problem of analysis and design of control systems in the presence of uncertainties. We treat uncertainties that affect a control system as random variables. The performance of the system is measured by the expectation of some derived random variables, which are typically bounded. We develop adaptive sequential randomized algorithms for estimating and optimizing the expectation of such bounded random variables with guaranteed accuracy and confidence level. These algorithms can be applied to overcome the conservatism and computational complexity in the analysis and design of controllers to be used in uncertain environments. We develop methods for investigating the optimality and computational complexity of such algorithms.

  14. Family control,institutional environment and cash dividend policy:Evidence from China

    Institute of Scientific and Technical Information of China (English)

    Zhihua; Wei; Shinong; Wu; Changqing; Li; Wei; Chen

    2011-01-01

    Using a sample of 1486 Chinese A-share listed companies for the period 2004-2008,this study empirically tests the impact of family control,institutional environment and their interaction on the cash dividend policy of listed companies.Our results indicate that(1)family firms have a lower cash dividend payout ratio and propensity to pay dividends than non-family firms;(2) a favorable regional institutional environment has a significant positive impact on the cash dividend payout ratio and propensity to pay dividends of listed companies;and(3) the impact of the regional institutional environment on cash dividends is stronger in family firms than in non-family firms.Somewhat surprisingly,we find that controlling family shareholders in China may intensify Agency Problem Ⅰ(the owner-manager conflict) rather than Agency Problem Ⅱ(the controlling shareholder-minority shareholder conflict),and thus have a significant negative impact on cash dividend policy.In contrast,a favorable regional institutional environment plays a positive corporate governance role in mitigating Agency Problem 1 and encouraging family firms to pay cash dividends.

  15. Identification and control of dissolved oxygen in hybridoma cell culture in a shear sensitive environment.

    Science.gov (United States)

    Simon, L; Karim, M N

    2001-01-01

    The productivity of mammalian cells can be enhanced by facilitating adequate oxygen transfer into the cultivation medium. However, current methods of controlling dissolved oxygen (DO) fail to account for alterations in medium composition during the course of the fermentation. These changes, which directly affect gas solubility and overall mass transfer coefficient, may be significant and deteriorate controller's performance in the long run. In this paper, the applications of Generalized Predictive Controllers (GPC) to DO control were investigated in a shear sensitive environment and compared to PID and Model Predictive Controllers (MPC). Input and output data for system identification were initially generated by varying the composition of oxygen fed into the bioreactor from 0 to 0.21 mol % while keeping the total inlet gas flow rate at 8.75 vvm. The process was identified using an AutoRegressive model with eXogeneous inputs (ARX) model and tested on different data sets. The model parameters were then correlated with the overall mass transfer coefficients. In simulation tests, the output of the PID controller switched from minimum to maximum values while more continuous control signals were obtained with the MPC and GPC controllers. When tested in a cell-free medium, all three controllers were able to track setpoint changes with some chattering observed in the control signals. The GPC outperformed the MPC and PID controllers when applied to the cultivation of hybridoma cells.

  16. Gait control in a soft robot by sensing interactions with the environment using self-deformation

    Science.gov (United States)

    Ishiguro, Akio; Trimmer, Barry A.

    2016-01-01

    All animals use mechanosensors to help them move in complex and changing environments. With few exceptions, these sensors are embedded in soft tissues that deform in normal use such that sensory feedback results from the interaction of an animal with its environment. Useful information about the environment is expected to be embedded in the mechanical responses of the tissues during movements. To explore how such sensory information can be used to control movements, we have developed a soft-bodied crawling robot inspired by a highly tractable animal model, the tobacco hornworm Manduca sexta. This robot uses deformations of its body to detect changes in friction force on a substrate. This information is used to provide local sensory feedback for coupled oscillators that control the robot's locomotion. The validity of the control strategy is demonstrated with both simulation and a highly deformable three-dimensionally printed soft robot. The results show that very simple oscillators are able to generate propagating waves and crawling/inching locomotion through the interplay of deformation in different body parts in a fully decentralized manner. Additionally, we confirmed numerically and experimentally that the gait pattern can switch depending on the surface contact points. These results are expected to help in the design of adaptable, robust locomotion control systems for soft robots and also suggest testable hypotheses about how soft animals use sensory feedback. PMID:28083114

  17. The attitude control of fixed-wing MAVS in turbulent environments

    Science.gov (United States)

    Mohamed, Abdulghani; Massey, Kevin; Watkins, Simon; Clothier, Reece

    2014-04-01

    The small scale and portability of fixed-wing Micro Aerial Vehicles lend them to many unique applications, however their utility is often limited by ineffective attitude control in turbulent environments. The performance of attitude control systems themselves are affected by a variety of factors. Assessment of this system’s performance needs to be viewed in relation to the MAVs’ unique constraints. Certain aspects and limitations of MAV attitude control related issues are addressed in the literature, but to fully address the degradation of utility, the entire system must be examined. These issues can only be fully addressed when considering them concurrently. There is no framework for defining the attitude control problem explicitly for MAVs. This paper attempts to (1) Define the MAV attitude control problem with respect to the unique constraints imposed by this class of Unmanned Aircraft; (2) Review current design trends of MAVs with respect to vulnerability to atmospheric turbulence.

  18. A fuzzy expert system to Trust-Based Access Control in crowdsourcing environments

    Directory of Open Access Journals (Sweden)

    Olusegun Folorunso

    2015-07-01

    Full Text Available Crowdsourcing has been widely accepted across a broad range of application areas. In crowdsourcing environments, the possibility of performing human computation is characterized with risks due to the openness of their web-based platforms where each crowd worker joins and participates in the process at any time, causing serious effect on the quality of its computation. In this paper, a combination of Trust-Based Access Control (TBAC strategy and fuzzy-expert systems was used to enhance the quality of human computation in crowdsourcing environment. A TBAC-fuzzy algorithm was developed and implemented using MATLAB 7.6.0 to compute trust value (Tvalue, priority value as evaluated by fuzzy inference system (FIS and finally generate access decision to each crowd-worker. In conclusion, the use of TBAC is feasible in improving quality of human computation in crowdsourcing environments.

  19. Performance-Driven Hybrid Full-Body Character Control for Navigation and Interaction in Virtual Environments

    Science.gov (United States)

    Mousas, Christos; Anagnostopoulos, Christos-Nikolaos

    2017-06-01

    This paper presents a hybrid character control interface that provides the ability to synthesize in real-time a variety of actions based on the user's performance capture. The proposed methodology enables three different performance interaction modules: the performance animation control that enables the direct mapping of the user's pose to the character, the motion controller that synthesizes the desired motion of the character based on an activity recognition methodology, and the hybrid control that lies within the performance animation and the motion controller. With the methodology presented, the user will have the freedom to interact within the virtual environment, as well as the ability to manipulate the character and to synthesize a variety of actions that cannot be performed directly by him/her, but which the system synthesizes. Therefore, the user is able to interact with the virtual environment in a more sophisticated fashion. This paper presents examples of different scenarios based on the three different full-body character control methodologies.

  20. Intricate environment-modulated genetic networks control isoflavone accumulation in soybean seeds

    Directory of Open Access Journals (Sweden)

    Shannon Grover

    2010-06-01

    Full Text Available Abstract Background Soybean (Glycine max [L] Merr. seed isoflavones have long been considered a desirable trait to target in selection programs for their contribution to human health and plant defense systems. However, attempts to modify seed isoflavone contents have not always produced the expected results because their genetic basis is polygenic and complex. Undoubtedly, the extreme variability that seed isoflavones display over environments has obscured our understanding of the genetics involved. Results In this study, a mapping population of RILs with three replicates was analyzed in four different environments (two locations over two years. We found a total of thirty-five main-effect genomic regions and many epistatic interactions controlling genistein, daidzein, glycitein and total isoflavone accumulation in seeds. The use of distinct environments permitted detection of a great number of environment-modulated and minor-effect QTL. Our findings suggest that isoflavone seed concentration is controlled by a complex network of multiple minor-effect loci interconnected by a dense epistatic map of interactions. The magnitude and significance of the effects of many of the nodes and connections in the network varied depending on the environmental conditions. In an attempt to unravel the genetic architecture underlying the traits studied, we searched on a genome-wide scale for genomic regions homologous to the most important identified isoflavone biosynthetic genes. We identified putative candidate genes for several of the main-effect and epistatic QTL and for QTL reported by other groups. Conclusions To better understand the underlying genetics of isoflavone accumulation, we performed a large scale analysis to identify genomic regions associated with isoflavone concentrations. We not only identified a number of such regions, but also found that they can interact with one another and with the environment to form a complex adaptable network

  1. Case-control studies of gene-environment interaction: Bayesian design and analysis.

    Science.gov (United States)

    Mukherjee, Bhramar; Ahn, Jaeil; Gruber, Stephen B; Ghosh, Malay; Chatterjee, Nilanjan

    2010-09-01

    With increasing frequency, epidemiologic studies are addressing hypotheses regarding gene-environment interaction. In many well-studied candidate genes and for standard dietary and behavioral epidemiologic exposures, there is often substantial prior information available that may be used to analyze current data as well as for designing a new study. In this article, first, we propose a proper full Bayesian approach for analyzing studies of gene-environment interaction. The Bayesian approach provides a natural way to incorporate uncertainties around the assumption of gene-environment independence, often used in such an analysis. We then consider Bayesian sample size determination criteria for both estimation and hypothesis testing regarding the multiplicative gene-environment interaction parameter. We illustrate our proposed methods using data from a large ongoing case-control study of colorectal cancer investigating the interaction of N-acetyl transferase type 2 (NAT2) with smoking and red meat consumption. We use the existing data to elicit a design prior and show how to use this information in allocating cases and controls in planning a future study that investigates the same interaction parameters. The Bayesian design and analysis strategies are compared with their corresponding frequentist counterparts.

  2. Cadmium and lead residue control in a hazard analysis and critical control point (HACCP) environment.

    Science.gov (United States)

    Pagan-Rodríguez, Doritza; O'Keefe, Margaret; Deyrup, Cindy; Zervos, Penny; Walker, Harry; Thaler, Alice

    2007-02-21

    In 2003-2004, the U.S. Department of Agriculture Food Safety and Inspection Service (FSIS) conducted an exploratory assessment to determine the occurrence and levels of cadmium and lead in randomly collected samples of kidney, liver, and muscle tissues of mature chickens, boars/stags, dairy cows, and heifers. The data generated in the study were qualitatively compared to data that FSIS gathered in a 1985-1986 study in order to identify trends in the levels of cadmium and lead in meat and poultry products. The exploratory assessment was necessary to verify that Hazard Analysis and Critical Control Point plans and efforts to control exposure to these heavy metals are effective and result in products that meet U.S. export requirements. A comparison of data from the two FSIS studies suggests that the incidence and levels of cadmium and lead in different slaughter classes have remained stable since the first study was conducted in 1985-1986. This study was conducted to fulfill FSIS mandate to ensure that meat, poultry, and egg products entering commerce in the United States are free of adulterants, including elevated levels of environmental contaminants such as cadmium and lead.

  3. Pigeon interaction mode switch-based UAV distributed flocking control under obstacle environments.

    Science.gov (United States)

    Qiu, Huaxin; Duan, Haibin

    2017-07-28

    Unmanned aerial vehicle (UAV) flocking control is a serious and challenging problem due to local interactions and changing environments. In this paper, a pigeon flocking model and a pigeon coordinated obstacle-avoiding model are proposed based on a behavior that pigeon flocks will switch between hierarchical and egalitarian interaction mode at different flight phases. Owning to the similarity between bird flocks and UAV swarms in essence, a distributed flocking control algorithm based on the proposed pigeon flocking and coordinated obstacle-avoiding models is designed to coordinate a heterogeneous UAV swarm to fly though obstacle environments with few informed individuals. The comparative simulation results are elaborated to show the feasibility, validity and superiority of our proposed algorithm. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  4. Standard Practice for Aerospace Cleanrooms and Associated Controlled Environments-Cleanroom Operations

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2004-01-01

    1.1 This practice specifies basic requirements, procedures, and practices for operating aerospace cleanrooms and controlled environments and precautions associated with the facility and equipment used. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  5. Active control of contaminant particulates in a low-earth-orbit near-spacecraft environment

    Science.gov (United States)

    Conger, J. C.; Hastings, D. E.

    1995-01-01

    The effectiveness of three possible active methods to clear and control micron-class contaminant particles in a spacecraft environment are examined. The first is the firing of cold gas jets to remove particles from the view angle of a sensor. The second is to modify the electric field surrounding the spacecraft so that the particles are repelled from the sensor. The third is to use electron beams to increase particulate charge so that ambient electromagnetic forces will have a greater effect.

  6. SENVM: Server Environment Monitoring and Controlling System for a Small Data Center Using Wireless Sensor Network

    OpenAIRE

    Choochaisri, Supasate; Niennattrakul, Vit; Jenjaturong, Saran; Intanagonwiwat, Chalermek; Ratanamahatana, Chotirat Ann

    2011-01-01

    In recent years, efficient energy utilization becomes an essential requirement for data centers, especially in data centers of world-leading companies, where "Green Data Center" defines a new term for an environment-concerned data center. Solutions to change existing a data center to the green one may vary. In the big company, high-cost approaches including re-planning server rooms, changing air-conditioners, buying low-powered servers, and equipping sophisticating environmental control equip...

  7. Minitron II system for precise control of the plant growth environment.

    Science.gov (United States)

    Knight, S L; Akers, C P; Akers, S W; Mitchell, C A

    1988-01-01

    A transparent, cylindrical chamber system was developed to allow measurement of gas-exchange by small crop canopies in the undisturbed plant growth environment. The system is an elaboration of the Minitron system developed previously to compare growth of small plants in different environments within the same general growth area. The Minitron II system described herein accommodates hydroponic culture and separate control of atmospheric composition in individual chambers. Root and shoot environments are compartmented separately to accommodate atmospheres of different flow rate and/or gaseous composition. A series of 0-rings and tension-adjustable springs allow carbon dioxide in the flowing atmosphere to be analyzed without cross-contamination between chamber compartments or from external gas sources. Carbon dioxide has been maintained at set point +/- 9 g m-3 over a range of CO2 concentrations from 382 to 2725 g m-3 and with an atmosphere turnover rate of 136.7 cm3 s-1 by computer-assisted mass flow controllers. Each chamber has dimensions large enough (61 cm internal diameter, 0.151 m3 internal volume) to allow adequate replication of individual plants for statistical purposes (e.g., up to 36 equally-spaced plant holders). No significant variation in growth or photosynthetic rate of leaf lettuce occurred between chambers for a given set of environmental conditions. Gas-exchange rates in different chambers changed to a similar extent as CO2 concentration in the flowing atmosphere or chamber temperature were varied by the same amount. When coupled with appropriate control systems, Minitron II chambers can provide separate controlled environments for multiple small plants with adequate precision and at relatively low cost.

  8. Use of microgravity sensors for quantification of space shuttle orbiter vernier reaction control system induced environments

    Science.gov (United States)

    Friend, Robert B.

    1998-01-01

    In the modeling of spacecraft dynamics it is important to accurately characterize the environment in which the vehicle operates, including the environments induced by the vehicle itself. On the Space Shuttle these induced environmental factors include reaction control system plume. Knowledge of these environments is necessary for performance of control systems and loads analyses, estimation of disturbances due to thruster firings, and accurate state vector propagation. During the STS-71 mission, while the Orbiter was performing attitude control for the mated Orbiter/Mir stack, it was noted that the autopilot was limit cycling at a rate higher than expected from pre-flight simulations. Investigations during the mission resulted in the conjecture that an unmodelled plume impingement force was acting upon the orbiter elevons. The in-flight investigations were not successful in determining the actual magnitude of the impingement, resulting in several sequential post-flight investigations. Efforts performed to better quantify the vernier reaction control system induced plume impingement environment of the Space Shuttle orbiter are described in this paper, and background detailing circumstances which required the more detailed knowledge of the RCS self impingement forces, as well as a description of the resulting investigations and their results is presented. The investigations described in this paper applied microgravity acceleration data from two shuttle borne microgravity experiments, SAMS and OARE, to the solution of this particular problem. This solution, now used by shuttle analysts and mission planners, results in more accurate propellant consumption and attitude limit cycle estimates in preflight analyses, which are critical for pending International Space Station missions.

  9. Integrating autonomous distributed control into a human-centric C4ISR environment

    Science.gov (United States)

    Straub, Jeremy

    2017-05-01

    This paper considers incorporating autonomy into human-centric Command, Control, Communications, Computers, Intelligence, Surveillance and Reconnaissance (C4ISR) environments. Specifically, it focuses on identifying ways that current autonomy technologies can augment human control and the challenges presented by additive autonomy. Three approaches to this challenge are considered, stemming from prior work in two converging areas. In the first, the problem is approached as augmenting what humans currently do with automation. In the alternate approach, the problem is approached as treating humans as actors within a cyber-physical system-of-systems (stemming from robotic distributed computing). A third approach, combines elements of both of the aforementioned.

  10. RADIATION ENVIRONMENT, ORGANIZATION AND PROVIDING OF POPULATION RADIATION PROTECTION CONTROL IN ST. PETBURG

    Directory of Open Access Journals (Sweden)

    I. A. Rakitin

    2008-01-01

    Full Text Available The article presents the analysis of radiation environment and work experience of Rospotrebnadzor Administration in St. Petersburg in the field of organizing of population radiation protection control and interaction with the local government executive bodies. It shows the level and structure of the city population collective doses from the main dose forming ionizing irradiation sources. It emphasizes the integrated method of solving the population exposure limitation issues based on the results of radiation-hygienic passport system and on the data from Uniform State System for Doses Control and Registration. The evaluation of the work being carried out is given.

  11. Simulation of three-phase induction motor drives using indirect field oriented control in PSIM environment

    Science.gov (United States)

    Aziri, Hasif; Patakor, Fizatul Aini; Sulaiman, Marizan; Salleh, Zulhisyam

    2017-09-01

    This paper presents the simulation of three-phase induction motor drives using Indirect Field Oriented Control (IFOC) in PSIM environment. The asynchronous machine is well known about natural limitations fact of highly nonlinearity and complexity of motor model. In order to resolve these problems, the IFOC is applied to control the instantaneous electrical quantities such as torque and flux component. As FOC is controlling the stator current that represented by a vector, the torque component is aligned with d coordinate while the flux component is aligned with q coordinate. There are five levels of the incremental system are gradually built up to verify and testing the software module in the system. Indeed, all of system build levels are verified and successfully tested in PSIM environment. Moreover, the corresponding system of five build levels are simulated in PSIM environment which is user-friendly for simulation studies in order to explore the performance of speed responses based on IFOC algorithm for three-phase induction motor drives.

  12. ASSESSMENT OF PROFESSIONAL SKILLS OF STUDENTS IN IT-BASED CONTROLLED EDUCATIONAL ENVIRONMENT OF A UNIVERSITY

    Directory of Open Access Journals (Sweden)

    Evgeiy Nikolaevich Boyarov

    2013-08-01

    Full Text Available The article looks at the problem of estimating professional skills of students, the process of their building and assessing their level in IT-based controlled educational environment of a university. The author presents research findings of professional skills level of future educational professionals in the field of Life Safety[1] based on their academic results.Goal: to develop and show by experiments efficiency of building professional skills of students in IT-based controlled educational environment of a university.Results: increasing the level of professional skills in IT-based controlled educational environment of a university.Scope of application of results: field of higher professional education.DOI: http://dx.doi.org/10.12731/2218-7405-2013-7-1[1] Life Safety or Fundamentals of Health and Safety is a secondary school subject, which involves teaching basic rules of how to act in dangerous situations in everyday life (natural disasters, fires, terrorist attacks, etc., provide first aid, etc.

  13. A research on the excavation, support, and environment control of large scale underground space

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Pil Chong; Kwon, Kwang Soo; Jeong, So Keul [Korea Institute of Geology Mining and Materials, Taejon (Korea, Republic of)

    1995-12-01

    With the growing necessity of the underground space due to the deficiency of above-ground space, the size and shape of underground structures tend to be complex and diverse. This complexity and variety force the development of new techniques for rock mass classification, excavation and supporting of underground space, monitoring and control of underground environment. All these techniques should be applied together to make the underground space comfortable. To achieve this, efforts have been made on 5 different areas; research on the underground space design and stability analysis, research on the techniques for excavation of rock by controlled blasting, research on the development of monitoring system to forecast the rock behaviour of underground space, research on the environment inspection system in closed space, and research on dynamic analysis of the airflow and environmental control in the large geos-spaces. The 5 main achievements are improvement of the existing structure analysis program(EXCRACK) to consider the deformation and failure characteristics of rock joints, development of new blasting design (SK-cut), prediction of ground vibration through the newly proposed wave propagation equation, development and In-Situ application of rock mass deformation monitoring system and data acquisition software, and trial manufacture of the environment inspection system in closed space. Should these techniques be applied to the development of underground space, prevention of industrial disaster, cut down of construction cost, domestication of monitoring system, improvement of tunnel stability, curtailment of royalty, upgrade of domestic technologies will be brought forth. (Abstract Truncated)

  14. Adaptation of SUBSTOR for controlled-environment potato production with elevated carbon dioxide

    Science.gov (United States)

    Fleisher, D. H.; Cavazzoni, J.; Giacomelli, G. A.; Ting, K. C.; Janes, H. W. (Principal Investigator)

    2003-01-01

    The SUBSTOR crop growth model was adapted for controlled-environment hydroponic production of potato (Solanum tuberosum L. cv. Norland) under elevated atmospheric carbon dioxide concentration. Adaptations included adjustment of input files to account for cultural differences between the field and controlled environments, calibration of genetic coefficients, and adjustment of crop parameters including radiation use efficiency. Source code modifications were also performed to account for the absorption of light reflected from the surface below the crop canopy, an increased leaf senescence rate, a carbon (mass) balance to the model, and to modify the response of crop growth rate to elevated atmospheric carbon dioxide concentration. Adaptations were primarily based on growth and phenological data obtained from growth chamber experiments at Rutgers University (New Brunswick, N.J.) and from the modeling literature. Modified-SUBSTOR predictions were compared with data from Kennedy Space Center's Biomass Production Chamber for verification. Results show that, with further development, modified-SUBSTOR will be a useful tool for analysis and optimization of potato growth in controlled environments.

  15. Optimized Control for Dynamical Performance of the Polishing Robot in Unstructured Environment

    Directory of Open Access Journals (Sweden)

    Zhong Luo

    2011-01-01

    Full Text Available In this paper, the dynamical performance of polishing robot working in unstructured environment is investigated. Structure mechanism and operating principle of a polishing robot are introduced firstly, and its dynamical model is established. Then, a S-shaped acceleration-deceleration path planning method and a human-simulated intelligent control (HSIC strategy are proposed. The S-shaped acceleration-deceleration path planning method is to switch the magnitude and direction of the abrupt velocities between motion sections in order to improve the work efficiency, the smoothness of movement and the processing accuracy. The HSIC control strategy is built based on the unstructured environment information measured by ultrasonic sensors, in which the appropriate programs prepared in advance are determined according to the size and sign of both the control error and its change rate. Simulation results show that the intelligent control strategy combining with optimum path planning method are effective to reduce the structure vibration, to improve the stability and the control accuracy of the polishing robot system.

  16. The Study of Reinforcement Learning for Traffic Self-Adaptive Control under Multiagent Markov Game Environment

    Directory of Open Access Journals (Sweden)

    Lun-Hui Xu

    2013-01-01

    Full Text Available Urban traffic self-adaptive control problem is dynamic and uncertain, so the states of traffic environment are hard to be observed. Efficient agent which controls a single intersection can be discovered automatically via multiagent reinforcement learning. However, in the majority of the previous works on this approach, each agent needed perfect observed information when interacting with the environment and learned individually with less efficient coordination. This study casts traffic self-adaptive control as a multiagent Markov game problem. The design employs traffic signal control agent (TSCA for each signalized intersection that coordinates with neighboring TSCAs. A mathematical model for TSCAs’ interaction is built based on nonzero-sum markov game which has been applied to let TSCAs learn how to cooperate. A multiagent Markov game reinforcement learning approach is constructed on the basis of single-agent Q-learning. This method lets each TSCA learn to update its Q-values under the joint actions and imperfect information. The convergence of the proposed algorithm is analyzed theoretically. The simulation results show that the proposed method is convergent and effective in realistic traffic self-adaptive control setting.

  17. Distributed virtual environment-based safety control for Internet tele-robots

    Institute of Scientific and Technical Information of China (English)

    Gao Yongsheng; Zhao Jie; Gao Sheng; Cai Hegao

    2006-01-01

    The inherent complexity and uncertainty of multi-operator multi-robot (MOMR) tele-operation system make its safeguard an essential problem. Hazardous factors in the system are analyzed using fault tree analysis(FTA) technology, and three-layer interactive safety architecture with information flow is designed in modules to control the factors according to the holistic control mode. After that, distributed virtual environment (DVE) including the characteristics of virtual guide (VG) technology is discussed to help the operators achieve some tasks through the visibility of control commands, time-delay, movement collision and operators' intentions. Finally an experiment is implemented to test the efficiency of safety control architecture by using two robots to place some building blocks in the same workspace.

  18. Distributed optimization-based control of multi-agent networks in complex environments

    CERN Document Server

    Zhu, Minghui

    2015-01-01

    This book offers a concise and in-depth exposition of specific algorithmic solutions for distributed optimization based control of multi-agent networks and their performance analysis. It synthesizes and analyzes distributed strategies for three collaborative tasks: distributed cooperative optimization, mobile sensor deployment and multi-vehicle formation control. The book integrates miscellaneous ideas and tools from dynamic systems, control theory, graph theory, optimization, game theory and Markov chains to address the particular challenges introduced by such complexities in the environment as topological dynamics, environmental uncertainties, and potential cyber-attack by human adversaries. The book is written for first- or second-year graduate students in a variety of engineering disciplines, including control, robotics, decision-making, optimization and algorithms and with backgrounds in aerospace engineering, computer science, electrical engineering, mechanical engineering and operations research. Resea...

  19. Development of a learning module using a virtual environment to demonstrate EMG and telerobotic control principles.

    Science.gov (United States)

    Patterson, P E

    2002-01-01

    A prototype system was developed for use as a teaching tool, allowing students to link EMG monitoring, data smoothing, robotic control, and neural network training within a rapid prototyping virtual environment (VE). The VE software allowed for the rapid development of scenarios and, when linked with EMG data input to a neural network, allowed the user to control an artificial world containing a virtual arm. Student teams then attempted to control the arm in the VE while performing the tasks by use of a neural network system they had specifically developed and trained using their own EMG signals. The results from their system were then translated into a form that enabled the control of a real robot. Students enjoyed the challenge and uniqueness of the module, and were enthusiastic about extending the concept to other areas of interest.

  20. RCTS: A flexible environment for sensor integration and control of robot systems; the distributed processing approach

    Science.gov (United States)

    Allard, R.; Mack, B.; Bayoumi, M. M.

    1989-01-01

    Most robot systems lack a suitable hardware and software environment for the efficient research of new control and sensing schemes. Typically, engineers and researchers need to be experts in control, sensing, programming, communication and robotics in order to implement, integrate and test new ideas in a robot system. In order to reduce this time, the Robot Controller Test Station (RCTS) has been developed. It uses a modular hardware and software architecture allowing easy physical and functional reconfiguration of a robot. This is accomplished by emphasizing four major design goals: flexibility, portability, ease of use, and ease of modification. An enhanced distributed processing version of RCTS is described. It features an expanded and more flexible communication system design. Distributed processing results in the availability of more local computing power and retains the low cost of microprocessors. A large number of possible communication, control and sensing schemes can therefore be easily introduced and tested, using the same basic software structure.

  1. Degradation of thermal control materials under a simulated radiative space environment

    Science.gov (United States)

    Sharma, A. K.; Sridhara, N.

    2012-11-01

    A spacecraft with a passive thermal control system utilizes various thermal control materials to maintain temperatures within safe operating limits. Materials used for spacecraft applications are exposed to harsh space environments such as ultraviolet (UV) and particle (electron, proton) irradiation and atomic oxygen (AO), undergo physical damage and thermal degradation, which must be considered for spacecraft thermal design optimization and cost effectiveness. This paper describes the effect of synergistic radiation on some of the important thermal control materials to verify the assumptions of beginning-of-life (BOL) and end-of-life (EOL) properties. Studies on the degradation in the optical properties (solar absorptance and infrared emittance) of some important thermal control materials exposed to simulated radiative geostationary space environment are discussed. The current studies are purely related to the influence of radiation on the degradation of the materials; other environmental aspects (e.g., thermal cycling) are not discussed. The thermal control materials investigated herein include different kind of second-surface mirrors, white anodizing, white paints, black paints, multilayer insulation materials, varnish coated aluminized polyimide, germanium coated polyimide, polyether ether ketone (PEEK) and poly tetra fluoro ethylene (PTFE). For this purpose, a test in the constant vacuum was performed reproducing a three year radiative space environment exposure, including ultraviolet and charged particle effects on North/South panels of a geostationary three-axis stabilized spacecraft. Reflectance spectra were measured in situ in the solar range (250-2500 nm) and the corresponding solar absorptance values were calculated. The test methodology and the degradations of the materials are discussed. The most important degradations among the low solar absorptance materials were found in the white paints whereas the rigid optical solar reflectors remained quite

  2. Controlling wear failure of graphite-like carbon film in aqueous environment: Two feasible approaches

    Energy Technology Data Exchange (ETDEWEB)

    Wang Yongxin [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Science, Lanzhou 730000 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Wang Liping, E-mail: lpwang@licp.cas.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Science, Lanzhou 730000 (China); Xue Qunji [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Science, Lanzhou 730000 (China)

    2011-02-15

    Friction and wear behaviors of graphite-like carbon (GLC) films in aqueous environment were investigated by a reciprocating sliding tribo-meter with ball-on-disc contact. Film structures and wear scars were studied by scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and a non-contact 3D surface profiler. A comprehensive wear model of the GLC film in aqueous environment was established, and two feasible approaches to control critical factor to the corresponding wear failure were discussed. Results showed that wear loss of GLC films in aqueous environment was characterized by micro-plough and local delamination. Due to the significant material loss, local delamination of films was critical to wear failure of GLC film in aqueous environment if the film was not prepared properly. The initiation and propagation of micro-cracks within whole films closely related to the occurrence of the films delamination from the interface between interlayer and substrate. The increase of film density by adjusting the deposition condition would significantly reduce the film delamination from substrate, meanwhile, fabricating a proper interlayer between substrate and GLC films to prevent the penetration of water molecules into the interface between interlayer and substrate could effectively eliminate the delamination.

  3. A navigation and control system for an autonomous rescue vehicle in the space station environment

    Science.gov (United States)

    Merkel, Lawrence

    1991-01-01

    A navigation and control system was designed and implemented for an orbital autonomous rescue vehicle envisioned to retrieve astronauts or equipment in the case that they become disengaged from the space station. The rescue vehicle, termed the Extra-Vehicular Activity Retriever (EVAR), has an on-board inertial measurement unit ahd GPS receivers for self state estimation, a laser range imager (LRI) and cameras for object state estimation, and a data link for reception of space station state information. The states of the retriever and objects (obstacles and the target object) are estimated by inertial state propagation which is corrected via measurements from the GPS, the LRI system, or the camera system. Kalman filters are utilized to perform sensor fusion and estimate the state propagation errors. Control actuation is performed by a Manned Maneuvering Unit (MMU). Phase plane control techniques are used to control the rotational and translational state of the retriever. The translational controller provides station-keeping or motion along either Clohessy-Wiltshire trajectories or straight line trajectories in the LVLH frame of any sufficiently observed object or of the space station. The software was used to successfully control a prototype EVAR on an air bearing floor facility, and a simulated EVAR operating in a simulated orbital environment. The design of the navigation system and the control system are presented. Also discussed are the hardware systems and the overall software architecture.

  4. Interaction Control Protocols for Distributed Multi-user Multi-camera Environments

    Directory of Open Access Journals (Sweden)

    Gareth W Daniel

    2003-10-01

    Full Text Available Video-centred communication (e.g., video conferencing, multimedia online learning, traffic monitoring, and surveillance is becoming a customary activity in our lives. The management of interactions in such an environment is a complicated HCI issue. In this paper, we present our study on a collection of interaction control protocols for distributed multiuser multi-camera environments. These protocols facilitate different approaches to managing a user's entitlement for controlling a particular camera. We describe a web-based system that allows multiple users to manipulate multiple cameras in varying remote locations. The system was developed using the Java framework, and all protocols discussed have been incorporated into the system. Experiments were designed and conducted to evaluate the effectiveness of these protocols, and to enable the identification of various human factors in a distributed multi-user and multi-camera environment. This work provides an insight into the complexity associated with the interaction management in video-centred communication. It can also serve as a conceptual and experimental framework for further research in this area.

  5. Amplitude Test for Input Devices for System Control in Immersive Virtual Environment

    DEFF Research Database (Denmark)

    Stenholt, Rasmus; Thornemann Hansen, Nina; Hald, Kasper

    2014-01-01

    In this study, the amplitudes best suited to compare four input devices are examined in the context of a pointer-based system control interface for immersive virtual environments. The interfaces are based on a pen and tablet, a touch tablet, hand-tracking using Kinect and a Wii Nunchuk analog sti...... menu using each combination of amplitude and interface. The amplitudes to be used for future experiments were found. Also, the movement times for the interfaces do not fit the predictions of Fitts' law.......In this study, the amplitudes best suited to compare four input devices are examined in the context of a pointer-based system control interface for immersive virtual environments. The interfaces are based on a pen and tablet, a touch tablet, hand-tracking using Kinect and a Wii Nunchuk analog stick....... This is done as a preliminary study in order to be able to compare the interfaces with the goal of evaluating them in the context of using virtual environments in a class lecture. Five amplitudes are tested for each of the four interfaces by having test participants mark menu elements in an eight-part radial...

  6. Integration of Environment Sensing and Control Functions for Robust Rotorcraft UAV (RUAV) Guidance

    Science.gov (United States)

    Dadkhah Tehrani, Navid

    Unmanned Air Vehicles (UAVs) have started supplanting manned aircraft in a broad range of tasks. Vehicles such as miniature rotorcrafts with broad maneuvering range and small size can enter remote locations that are hard to reach using other air and ground vehicles. Developing a guidance system which enables a Rotorcraft UAV (RUAV) to perform such tasks involves combing key elements from robotics motion planning, control system design, trajectory optimization as well as dynamics modeling. The focus of this thesis is to integrate a guidance system for a small-scale rotorcraft to enable a high level of performance and situational awareness. We cover large aspects of the system integration including modeling, control system design, environment sensing as well as motion planning in the presence of uncertainty. The system integration in this thesis is performed around a Blade-CX2 miniature coaxial helicopter. The first part of the thesis focuses on the development of the parameterized model for the Blade-CX2 helicopter with an emphasis on the coaxial rotor configuration. The model explicitly accounts for the dynamics of lower rotor and uses an implicit lumped parameter model for the upper rotor and stabilizer-bar. The parameterized model was identified using frequency domain system identification. In the second part of the thesis, we use the identified model to design a control law for the Blade-CX2 helicopter. The control augmentation for the Blade-CX2 helicopter was based on a nested attitude-velocity loop control architecture and was designed following classical loop-shaping and dynamic inversion techniques. A path following layer wrapped around the velocity control system enables the rotorcraft to follow reference trajectories specified by a sequence of waypoints and velocity vectors. Such reference paths are common in autonomous guidance systems. Finally, the third part of the thesis addresses the problem of autonomous navigation through a partially known or

  7. Power assist control of electric bicycle taking environment and rider's condition into account

    Science.gov (United States)

    Niki, Hiroshi; Miyata, Junichi; Murakami, Toshiyuki

    2005-12-01

    Recently, bicycles are widely used as a convenient transportation tool. But from a viewpoint of wide use for the future aging society, it is problem to pedal on rider's own. As well known, power assistance bicycle has already been used. The power assistance bicycle helps the elderly people or the people who has weak legs to expand their field. However, existing power assistance bicycle doesn't take running environment and rider's condition into account. The new control algorithm for power assistance bicycle is proposed in this paper. Human input and running friction are estimated as a disturbance torque with a disturbance observer. By using high pass filter (HPF), human input is separated from running friction. This method realizes power assistance bicycle without torque sensor. Disturbance observer compensates running friction. Compliance control is applied to make the bicycle have desired compliance. The effectiveness of this control algorithm is verified by numerical and experimental results.

  8. Board independence, internal information environment and voluntary disclosure of auditors’ reports on internal controls

    Institute of Scientific and Technical Information of China (English)

    Ye Sun; Yang Yi; Bin Lin

    2012-01-01

    When there is high information asymmetry between directors and managers,independent directors do not have enough information to perform their functions. Only when faced with a good internal information environment can such directors acquire enough information to provide advice and monitor managers,and only under these conditions can increasing their proportion on the board effectively reduce agency problems, such as driving managers to disclose information to investors. Using a sample of Chinese listed firms that voluntarily disclose their auditors’ reports on internal controls from 2007 to 2009, this study explores how the information acquisition costs of independent directors affect their monitoring effectiveness by investigating the disclosure decisions of their internal control audits. We find that when the information asymmetry between insiders and outside directors is low and the proportion of independent directors on a board is high, a firm is more likely to voluntarily disclose its internal control audit report.

  9. Board independence, internal information environment and voluntary disclosure of auditors’ reports on internal controls

    Directory of Open Access Journals (Sweden)

    Ye Sun

    2012-06-01

    Full Text Available When there is high information asymmetry between directors and managers, independent directors do not have enough information to perform their functions. Only when faced with a good internal information environment can such directors acquire enough information to provide advice and monitor managers, and only under these conditions can increasing their proportion on the board effectively reduce agency problems, such as driving managers to disclose information to investors. Using a sample of Chinese listed firms that voluntarily disclose their auditors’ reports on internal controls from 2007 to 2009, this study explores how the information acquisition costs of independent directors affect their monitoring effectiveness by investigating the disclosure decisions of their internal control audits. We find that when the information asymmetry between insiders and outside directors is low and the proportion of independent directors on a board is high, a firm is more likely to voluntarily disclose its internal control audit report.

  10. Controls and variability of solute and sedimentary fluxes in Antarctic and sub-Antarctic Environments

    Science.gov (United States)

    Zwolinski, Zbigniew

    2015-04-01

    . Solute and sediment transport in the streams of analyzed environments are constrained by the relatively short water runoff season that typically lasts from a few weeks to maximum of four months during the austral summer, for Antarctic and sub-Antarctic regions respectively. Because of high intensity of mechanical and chemical weathering processes solute and sediment transport are rather high within Antarctic environments. Weathering rates on slopes and magnitude of fluvial transport in relatively short streams control the intensity of denudational processes. Both mechanical and chemical denudation varies highly through sub-Antarctic and Antarctic environments. To generate accurate predictions of fluvial and denudational processes we must fully understand the actual geoecological processes, which in some places are under rapid change, e.g., the Antarctic Peninsula and sub-Antarctic islands.

  11. Proposal of inspection methodology for environment radiological control; Proposta de metodologia de inspecao para controle radiologico ambiental

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Nadia Soido Falcao

    2005-07-01

    The Radiation Protection and Dosimetry Institute (IRD) of the Brazilian Nuclear Energy Commission (CNEN) is in charge of verifying that the self-monitoring operator is effective to control the radiological quality of environmental around the nuclear facilities and carried out in accordance with the regulatory requirements. While a long time, the verification of compliance was kept by the conduction of large scale monitoring programs around all the authorized installations. The IRD decided to reformulate its performance behavior, starting another kind of control program, due to the number increase of nuclear installations and the diversity of activities conducted by the operators. This program, so-called Monitoring Control Program (PCM) is a regulatory activity developed by the Environmental Impact Assessment Service (SEAIA) of IRD and has the aim of check the effectiveness of authorized self-control. Actually the regulatory control of environmental radiological integrity around the authorized nuclear installation essentially depends on the effectiveness of regulatory inspections fulfilled by the SEAIA/IRD. Due to the implementation of modern practices of management in the IRD, specially the quality management system on regulatory inspection activities, emerged the need of unify these actions. It was also necessary to establish standard procedures required for inspection conduction. This work proposes one methodology for the inspections of environmental radiological control suitable to assure the compliance and effectiveness of environmental and effluent monitoring programs conducted by the operator, through the systematic verification of compliance and data quality assessment. The proposed methodology seeks to attend the appeals for high control standards of environment protection and public health. Here, we presented as products of this work: The inspection handbook and checklists for inspections; one framework for sampling, handling, recording and reporting of

  12. USABILITY EVALUATION OF A CONTROL AND PROGRAMMING ENVIRONMENT FOR PROGRAMMING EDUCATION

    Directory of Open Access Journals (Sweden)

    Maísa S. dos S. Lopes

    2016-07-01

    Full Text Available This paper presents an assessment of usability of Control and Programming Environment (CPE of a remote mobile robot. The CPE is an educational environment focused on computer programming education that integrates a program development online tool with a remote lab. To evaluate system usability, empirical test was conducted with computer science students in order to identify the views of users on the system and get directions on how to improve the quality of interface use. The study used questionnaire and observation of the evaluator. The degree of users’ satisfaction was measured by using a quantitative approach that establishes the average ranking for each question of the questionnaire. The results indicate that the system is simple, easy to use and suited to programming practices, however needed changes to make it more intuitive and efficient. The realization test of usability, even with a small sample user, is important to provide feedback on the system's user experience and help identify problems.

  13. Flexible sample environment for high resolution neutron imaging at high temperatures in controlled atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Makowska, Małgorzata G., E-mail: malg@dtu.dk [Department of Energy Conversion and Storage, Technical University of Denmark, Roskilde 4000 (Denmark); European Spallation Source ESS AB, P.O. Box 176, SE-221 00 Lund (Sweden); Theil Kuhn, Luise; Cleemann, Lars N. [Department of Energy Conversion and Storage, Technical University of Denmark, Roskilde 4000 (Denmark); Lauridsen, Erik M. [Xnovo Technology ApS, Galoche Alle 15, Køge 4600 (Denmark); Bilheux, Hassina Z.; Molaison, Jamie J.; Santodonato, Louis J. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Tremsin, Anton S. [Space Sciences Laboratory, University of California at Berkeley, Berkeley, California 94720 (United States); Grosse, Mirco [Institute for Applied Material Research, Karlsruhe Institute of Technology, Karlsruhe DE-76021 (Germany); Morgano, Manuel [Paul Scherrer Institut, Villigen PSI CH-5232 (Switzerland); Kabra, Saurabh [ISIS, Rutherford Appleton Laboratory, Chilton OX11 0QX (United Kingdom); Strobl, Markus [European Spallation Source ESS AB, P.O. Box 176, SE-221 00 Lund (Sweden)

    2015-12-15

    High material penetration by neutrons allows for experiments using sophisticated sample environments providing complex conditions. Thus, neutron imaging holds potential for performing in situ nondestructive measurements on large samples or even full technological systems, which are not possible with any other technique. This paper presents a new sample environment for in situ high resolution neutron imaging experiments at temperatures from room temperature up to 1100 °C and/or using controllable flow of reactive atmospheres. The design also offers the possibility to directly combine imaging with diffraction measurements. Design, special features, and specification of the furnace are described. In addition, examples of experiments successfully performed at various neutron facilities with the furnace, as well as examples of possible applications are presented. This covers a broad field of research from fundamental to technological investigations of various types of materials and components.

  14. Geological Environment Problems Caused by Controlling Groundwater Exploitation in Jiangyin City

    Institute of Scientific and Technical Information of China (English)

    DENG Qing-hai; MA Feng-shan; YUAN Ren-mao; YAO Bing-kui

    2007-01-01

    Geological environment effects caused by the control of groundwater exploitation in Jiangyin city are discussed thoroughly, including the dynamic variation of groundwater levels and quality and the development of land subsidence and ground fissures. According to the dynamic characteristics of groundwater levels, some advice about groundwater exploitation is offered. Our research will provide a basis for using groundwater resources and the prevention of geological disasters in Jiangyin city and the Suzhou-Wuxi-Changzhou area. The following results are deduced from our research. First, groundwater levels vary with the exploitation of groundwater in Jiangyin city and are affected by hydrogeological conditions. The groundwater levels remained rather stable before and after the implementation of control of groundwater exploitation in the northwest of Jiangyin city along the Yangtze River. A suitable level of exploitation should be allowed. In the southeast, the speed of recovery of the groundwater level has been rather rapid after the control of exploitation. We conclude that groundwater might be exploited locally after the groundwater level has recovered. In the southwest, the speed of recovery of the groundwater level is rather slow and exploitation of groundwater should be prohibited. Second, groundwater quality is stable in Jiangyin city and the contents of the main chemical indices of groundwater varied only slightly before and after the control of exploitation. Third, after controlling the exploitation, the speed of land subsidence has clearly slowed down and the development of ground fissures has been controlled effectively.

  15. Evolutionary Fuzzy Control and Navigation for Two Wheeled Robots Cooperatively Carrying an Object in Unknown Environments.

    Science.gov (United States)

    Juang, Chia-Feng; Lai, Min-Ge; Zeng, Wan-Ting

    2015-09-01

    This paper presents a method that allows two wheeled, mobile robots to navigate unknown environments while cooperatively carrying an object. In the navigation method, a leader robot and a follower robot cooperatively perform either obstacle boundary following (OBF) or target seeking (TS) to reach a destination. The two robots are controlled by fuzzy controllers (FC) whose rules are learned through an adaptive fusion of continuous ant colony optimization and particle swarm optimization (AF-CACPSO), which avoids the time-consuming task of manually designing the controllers. The AF-CACPSO-based evolutionary fuzzy control approach is first applied to the control of a single robot to perform OBF. The learning approach is then applied to achieve cooperative OBF with two robots, where an auxiliary FC designed with the AF-CACPSO is used to control the follower robot. For cooperative TS, a rule for coordination of the two robots is developed. To navigate cooperatively, a cooperative behavior supervisor is introduced to select between cooperative OBF and cooperative TS. The performance of the AF-CACPSO is verified through comparisons with various population-based optimization algorithms for the OBF learning problem. Simulations and experiments verify the effectiveness of the approach for cooperative navigation of two robots.

  16. Implementing Internet of Things in a military command and control environment

    Science.gov (United States)

    Raglin, Adrienne; Metu, Somiya; Russell, Stephen; Budulas, Peter

    2017-05-01

    While the term Internet of Things (IoT) has been coined relatively recently, it has deep roots in multiple other areas of research including cyber-physical systems, pervasive and ubiquitous computing, embedded systems, mobile ad-hoc networks, wireless sensor networks, cellular networks, wearable computing, cloud computing, big data analytics, and intelligent agents. As the Internet of Things, these technologies have created a landscape of diverse heterogeneous capabilities and protocols that will require adaptive controls to effect linkages and changes that are useful to end users. In the context of military applications, it will be necessary to integrate disparate IoT devices into a common platform that necessarily must interoperate with proprietary military protocols, data structures, and systems. In this environment, IoT devices and data will not be homogeneous and provenance-controlled (i.e. single vendor/source/supplier owned). This paper presents a discussion of the challenges of integrating varied IoT devices and related software in a military environment. A review of contemporary commercial IoT protocols is given and as a practical example, a middleware implementation is proffered that provides transparent interoperability through a proactive message dissemination system. The implementation is described as a framework through which military applications can integrate and utilize commercial IoT in conjunction with existing military sensor networks and command and control (C2) systems.

  17. Synthetic control of flowering in rice independent of the cultivation environment.

    Science.gov (United States)

    Okada, Ryo; Nemoto, Yasue; Endo-Higashi, Naokuni; Izawa, Takeshi

    2017-03-27

    For genetically homogeneous crops, the timing of flowering is determined largely by the cultivation environment and is strongly associated with the yield and quality of the harvest(1). Flowering time and other agronomical traits are often tightly correlated, which can lead to difficulty excluding the effects of flowering time when evaluating the characteristics of different genetic varieties(2). Here, we describe the development of transgenic rice plants whose flowering time can be controlled by specific agrochemicals. We first developed non-flowering rice plants by overexpressing a floral repressor gene, Grain number, plant height and heading date 7 (Ghd7)(3,4), to inhibit any environmentally induced spontaneous flowering. We then co-transformed plants with a rice florigen gene, Heading date 3a (Hd3a)(5), which is induced by the application of specific agrochemicals. This permitted the flowering time to be experimentally controlled regardless of the cultivation environment: some transgenic plants flowered only after agrochemical treatment. Furthermore, plant size and yield-related traits could, in some cases, be increased owing to both a longer duration of vegetative growth and an increased panicle size. This ability to control flowering time experimentally, independently of environmental variables, may lead to production of crops suitable for growth in different climates and facilitate breeding for various agronomical traits.

  18. A modular, computer-controlled system for olfactory stimulation in the MRI environment.

    Science.gov (United States)

    Andrieu, Patrice; Bonnans, Vincent; Meneses, Jaime; Millot, Jean-Louis; Moulin, Thierry; Gharbi, Tijani

    2014-03-01

    Although the cerebral networks involved in sensory perception are of general interest in neuroscience, registration of the effects of olfactory stimulation, especially in a magnetic resonance imaging (MRI) environment, presents particular problems and constraints. This article presents details of a reliable and portable system for olfactory stimulation that is modular in design and based on microcontroller technology. It has the following characteristics: (1) It is under software control; (2) the presentation of olfactory stimulation can be synchronized with respiration; (3) it can be manually controlled; and (4) it is fully compatible with an MRI environment. The principle underlying this system is to direct an odor to the subject's nostrils by switching airflow to different odor diffusers. The characteristics of this system were established using (1) ultraviolet (UV) spectroscopy, to measure its response time, and (2) gas chromatography, to measure the repeatability of odor presentation in terms of gas concentration. A response time of 200 ± 25 ms was obtained for the system, and the standard deviations of the gas concentration delivered during stimulation ranged from 1.5% to 22%, depending on the odor, the airflow, and the dilution of the odor used. Since it is portable, controlled by software, and reliable, on the basis of the results we obtained, this system will lend itself to a wide range of applications in olfactory neuroscience.

  19. Controlling the Short-Range Propagation Environment Using Active Frequency Selective Surfaces

    Directory of Open Access Journals (Sweden)

    L. Subrt

    2010-12-01

    Full Text Available This paper deals with a new approach to the control of the propagation environment in indoor scenarios using intelligent walls. The intelligent wall is a conventional wall situated inside a building, but equipped with an active frequency selective surface and sensors. The intelligent wall can be designed as a self-configuring and self-optimizing autonomous part of a collaborative infrastructure working within a high-capacity mobile radio system. The paper shows how such surfaces can be used to adjust the electromagnetic characteristics of the wall in response to changes in traffic demand, monitored using a network of sensors, thereby controlling the propagation environment inside the building. Some of the potential problems (mainly controlling coverage and interference relating to an increased usage of wireless systems both inside and outside buildings are discussed and possible solutions using intelligent walls with the active FSS are suggested. The positive influence of intelligent walls on system performance is shown and results obtained from the simulations are shown and discussed.

  20. Flexible operation strategy for environment control system in abnormal supply power condition

    Science.gov (United States)

    Liping, Pang; Guoxiang, Li; Hongquan, Qu; Yufeng, Fang

    2017-04-01

    This paper establishes an optimization method that can be applied to the flexible operation of the environment control system in an abnormal supply power condition. A proposed conception of lifespan is used to evaluate the depletion time of the non-regenerative substance. The optimization objective function is to maximize the lifespans. The optimization variables are the allocated powers of subsystems. The improved Non-dominated Sorting Genetic Algorithm is adopted to obtain the pareto optimization frontier with the constraints of the cabin environmental parameters and the adjustable operating parameters of the subsystems. Based on the same importance of objective functions, the preferred power allocation of subsystems can be optimized. Then the corresponding running parameters of subsystems can be determined to ensure the maximum lifespans. A long-duration space station with three astronauts is used to show the implementation of the proposed optimization method. Three different CO2 partial pressure levels are taken into consideration in this study. The optimization results show that the proposed optimization method can obtain the preferred power allocation for the subsystems when the supply power is at a less-than-nominal value. The method can be applied to the autonomous control for the emergency response of the environment control system.

  1. Nap environment control considering respiration rate and music tempo by using sensor agent robot

    Science.gov (United States)

    Nakaso, Sayaka; Mita, Akira

    2015-03-01

    We propose a system that controls a nap environment considering respiration rates and music tempo by using a sensor agent robot. The proposed system consists of two sub-systems. The first sub-system measures respiration rates using optical flow. We conducted preparatory experiments to verify the accuracy of this sub-system. The experimental results showed that this sub-system can measure the respiration rates accurately despite several positional relationships. It was also shown that the accuracy could be affected by clothes, movements and light. The second sub-system we constructed was the music play sub-system that chooses music with the certain tempo corresponding to the respiration rates measured by the first sub-system. We conducted verification experiments to verify the effectiveness of this music play sub-system. The experimental results showed the effectiveness of varying music tempo based on the respiration rates in taking a nap. We also demonstrated this system in a real environment; a subject entered into the room being followed by ebioNα. When the subject was considered sleeping, ebioNα started measuring respiration rates, controlling music based on the respiration rates. As a result, we showed that this system could be realized. As a next step, we would like to improve this system to a nap environment control system to be used in offices. To realize this, we need to update the first sub-system measuring respiration rates by removing disturbances. We also need to upgrade music play sub-system considering the numbers of tunes, the kinds of music and time to change music.

  2. ROMANIA’S FACTS ABOUT INTERNAL CONTROL ENVIRONMENT OF EUROPEAN SOCIAL FUND FINANCED PROJECTS

    Directory of Open Access Journals (Sweden)

    Dogar Cristian

    2012-07-01

    Full Text Available The malfunctioning of internal control system of European Social Fund (ESF financed interventions may prejudice the sound financial management principle. Incorporating COSO principles in the beneficiary’s internal control systems may provide some warranties about compliance to the above mentioned principle as described in the EC Regulation 1605-2002. This study aims to explore some facts in actual internal control environment, as a base for future improvements of Romanian ESF beneficiary’s internal control systems ESF financed interventions covers a large range of costs for implementing labor market related services. But supporting costs according to the sound financial management principle calls for best value for money in real and legal operations. Without some specifics from the donor or a mutual accepted best practice model, most of the ESF beneficiaries are reporting their efforts to actual researches and specialized literature regarding internal control system implementation in services. This study was realized in April 2012 by applying an investigation instrument, an on-line questionnaire collecting both opinions and factual data as well to a number of 962 members of a practice community for ESF interventions implementation. This technique was used to test hypotheses regarding the premises existence for a future improvement of the existing internal control system model. 100 members of this community: managers, accountants, auditors financial responsible and other team members answered anonymously, revealing a real concern for internal control, providing as well a different side image for this. Analyzing all stakeholder answers, we may consider that our hypothesis is correct and there is a real need for internal control environment improvements. This study is a part of a larger research “New models of the accounting and internal control systems of ESF financed interventions in Romania”, addressing a qualitative

  3. Comfort and performance impact of personal control over thermal environment in summer

    DEFF Research Database (Denmark)

    Boerstra, Atze C.; te Kulve, Marije; Toftum, Jørn

    2015-01-01

    recorded during the first session. Thus, each subject was exposed to two customized conditions with identical exposure, only different from a psychological point of view.During the two sessions identical questionnaires and performance tests were used to evaluate subjects' comfort, SBS symptom incidence...... and performance. As expected, perceived control over the environment was significantly higher during session A, but there were no differences in perceived comfort and SBS symptom intensity. Both self-assessed and objectively measured performance was significantly better during session B. About two...

  4. An experiment towards characterizing seahorse sound in a laboratory controlled environment

    Digital Repository Service at National Institute of Oceanography (India)

    Saran, A; Sreepada, R.A; Chakraborty, B.; Fernandes, W.A; Srivastava, R.; Kuncolienker, D.S.; Gawde, G.

    N a t i o n a l C o n f e r e n c e o n E l e c t r o n i c T e c h n o l o g i e s 1 5 t h & 1 6 t h A p r i l 2 K 1 1 | 138 An Experiment towards Characterizing Seahorse Sound in a Laboratory Controlled Environment Arvind K. Saran1, R.... A. Sreepada1, Bishwajit Chakraborty1, William Fernandes1, Ratan Srivastava1 1National Institute of Oceanography, Dona Paula, Goa, India Dinanath Sinai Kuncolienker 2 , Gajanan Gawde2 2Goa Engineering College, Farmagudi Ponda, Goa, India...

  5. Dynamics of a Stage Structured Pest Control Model in a Polluted Environment with Pulse Pollution Input

    Directory of Open Access Journals (Sweden)

    Bing Liu

    2013-01-01

    Full Text Available By using pollution model and impulsive delay differential equation, we formulate a pest control model with stage structure for natural enemy in a polluted environment by introducing a constant periodic pollutant input and killing pest at different fixed moments and investigate the dynamics of such a system. We assume only that the natural enemies are affected by pollution, and we choose the method to kill the pest without harming natural enemies. Sufficient conditions for global attractivity of the natural enemy-extinction periodic solution and permanence of the system are obtained. Numerical simulations are presented to confirm our theoretical results.

  6. Optimal feedback control of two-qubit entanglement in dissipative environments

    Science.gov (United States)

    Rafiee, Morteza; Nourmandipour, Alireza; Mancini, Stefano

    2016-07-01

    We study the correction of errors intervening in two qubits dissipating into their own environments. This is done by resorting to local feedback actions with the aim of preserving as much as possible the initial amount of entanglement. Optimal control is found first by gaining insights from the subsystem purity and then by numerical analysis on the concurrence. This is tantamount to a double optimization on the actuation and on the measurement processes. Repeated feedback action is also investigated, thus paving the way for a continuous-time formulation and a solution of the problem.

  7. Dynamic control of coherent orbital-angular-momentum beams in turbid environments

    Science.gov (United States)

    Morgan, K. S.; Miller, J. K.; Cochenour, B. M.; Johnson, E. G.

    2016-05-01

    This work examines the propagation properties of two superimposed coherent orbital angular momentum (OAM) modes for use in underwater systems as an alternative to amplitude modulation. An OAM mode of l=+2 is interfered with OAM mode l=-1 from a λ = 540 nm laser source. These OAM modes are superimposed using a Mach-Zehnder (MZ) interferometer combined with diffractive optical elements. By manipulating the optical path length of one of the MZ legs, the interference of these beams can be temporally controlled. The spatial profile is maintained in a turbid environment up through 4.9 attenuation lengths for both cases.

  8. An optimal control strategy for collision avoidance of mobile robots in non-stationary environments

    Science.gov (United States)

    Kyriakopoulos, K. J.; Saridis, G. N.

    1991-01-01

    An optimal control formulation of the problem of collision avoidance of mobile robots in environments containing moving obstacles is presented. Collision avoidance is guaranteed if the minimum distance between the robot and the objects is nonzero. A nominal trajectory is assumed to be known from off-line planning. The main idea is to change the velocity along the nominal trajectory so that collisions are avoided. Furthermore, time consistency with the nominal plan is desirable. A numerical solution of the optimization problem is obtained. Simulation results verify the value of the proposed strategy.

  9. Long-term tracking of microbial survivability and growth in a controlled environment

    Science.gov (United States)

    Sutandar, Andiyanto; Abdiel Foo, Jong Yong; Lim, Chu Sing; Hsu, Li-Yang

    2008-04-01

    The ecological and histological study of a microbial population in a given environment provides important information leading to its survivability and growth. Current standard laboratory practices adopt culture on a medium housed in an incubated environment. However, large numbers of cultures are usually required to investigate the effects of variations in parametric conditions on the microbes. This can result in a high use of resources such as consumables and man-hours. Automated systems that are able to replenish fresh nutrients and extract metabolic waste for long-term monitoring are also limited. In this study, a system capable of real-time monitoring of microbe survival and providing a suitable environment for their growth is presented. Housed within its structure is a customized chamber with temperature control, pH regulation, nutrient providence and metabolic waste removal functions. To assess the reliability of the system, five sets of Staphylococcus aureus ATCC 29213 strains are cultured and monitored continuously for 96 consecutive hours. The survival and growth of the pathogens are verified by standard laboratory techniques such as viable plate count after each successive 24 h of monitoring. The findings herein suggest that the system is able to monitor the microbial population with minimal human intervention and can be a valuable long-term tracking tool.

  10. Orion Exploration Flight Test Reaction Control System Jet Interaction Heating Environment from Flight Data

    Science.gov (United States)

    White, Molly E.; Hyatt, Andrew J.

    2016-01-01

    The Orion Multi-Purpose Crew Vehicle (MPCV) Reaction Control System (RCS) is critical to guide the vehicle along the desired trajectory during re-­-entry. However, this system has a significant impact on the convective heating environment to the spacecraft. Heating augmentation from the jet interaction (JI) drives thermal protection system (TPS) material selection and thickness requirements for the spacecraft. This paper describes the heating environment from the RCS on the afterbody of the Orion MPCV during Orion's first flight test, Exploration Flight Test 1 (EFT-1). These jet plumes interact with the wake of the crew capsule and cause an increase in the convective heating environment. Not only is there widespread influence from the jet banks, there may also be very localized effects. The firing history during EFT-1 will be summarized to assess which jet bank interaction was measured during flight. Heating augmentation factors derived from the reconstructed flight data will be presented. Furthermore, flight instrumentation across the afterbody provides the highest spatial resolution of the region of influence of the individual jet banks of any spacecraft yet flown. This distribution of heating augmentation across the afterbody will be derived from the flight data. Additionally, trends with possible correlating parameters will be investigated to assist future designs and ground testing programs. Finally, the challenges of measuring JI, applying this data to future flights and lessons learned will be discussed.

  11. Robust control of the seasonal expression of the Arabidopsis FLC gene in a fluctuating environment.

    Science.gov (United States)

    Aikawa, Shinichiro; Kobayashi, Masaki J; Satake, Akiko; Shimizu, Kentaro K; Kudoh, Hiroshi

    2010-06-22

    Plants flower in particular seasons even in natural, fluctuating environments. The molecular basis of temperature-dependent flowering-time regulation has been extensively studied, but little is known about how gene expression is controlled in natural environments. Without a memory of past temperatures, it would be difficult for plants to detect seasons in natural, noisy environments because temperature changes occurring within a few weeks are often inconsistent with seasonal trends. Our 2-y census of the expression of a temperature-dependent flowering-time gene, AhgFLC, in a natural population of perennial Arabidopsis halleri revealed that the regulatory system of this flowering-time gene extracts seasonal cues as if it memorizes temperatures over the past 6 wk. Time-series analysis revealed that as much as 83% of the variation in the AhgFLC expression is explained solely by the temperature for the previous 6 wk, but not by the temperatures over shorter or longer periods. The accuracy of our model in predicting the gene expression pattern under contrasting temperature regimes in the transplant experiments indicates that such modeling incorporating the molecular bases of flowering-time regulation will contribute to predicting plant responses to future climate changes.

  12. Local Control of Audio Environment: A Review of Methods and Applications

    Directory of Open Access Journals (Sweden)

    Jussi Kuutti

    2014-02-01

    Full Text Available The concept of a local audio environment is to have sound playback locally restricted such that, ideally, adjacent regions of an indoor or outdoor space could exhibit their own individual audio content without interfering with each other. This would enable people to listen to their content of choice without disturbing others next to them, yet, without any headphones to block conversation. In practice, perfect sound containment in free air cannot be attained, but a local audio environment can still be satisfactorily approximated using directional speakers. Directional speakers may be based on regular audible frequencies or they may employ modulated ultrasound. Planar, parabolic, and array form factors are commonly used. The directivity of a speaker improves as its surface area and sound frequency increases, making these the main design factors for directional audio systems. Even directional speakers radiate some sound outside the main beam, and sound can also reflect from objects. Therefore, directional speaker systems perform best when there is enough ambient noise to mask the leaking sound. Possible areas of application for local audio include information and advertisement audio feed in commercial facilities, guiding and narration in museums and exhibitions, office space personalization, control room messaging, rehabilitation environments, and entertainment audio systems.

  13. HmsC Controls Yersinia pestis Biofilm Formation in Response to Redox Environment

    Directory of Open Access Journals (Sweden)

    Gai-Xian Ren

    2017-08-01

    Full Text Available Yersinia pestis biofilm formation, controlled by intracellular levels of the second messenger molecule cyclic diguanylate (c-di-GMP, is important for blockage-dependent plague transmission from fleas to mammals. HmsCDE is a tripartite signaling system that modulates intracellular c-di-GMP levels to regulate biofilm formation in Y. pestis. Previously, we found that Y. pestis biofilm formation is stimulated in reducing environments in an hmsCDE-dependent manner. However, the mechanism by which HmsCDE senses the redox state remains elusive. Using a dsbA mutant and the addition of Cu2+ to simulate reducing and oxidizing periplasmic environments, we found that HmsC protein levels are decreased and the HmsC-HmsD protein-protein interaction is weakened in a reducing environment. In addition, we revealed that intraprotein disulphide bonds are critical for HmsC since breakage lowers protein stability and diminishes the interaction with HmsD. Our results suggest that HmsC might play a major role in sensing the environmental changes.

  14. UAV formation control design with obstacle avoidance in dynamic three-dimensional environment.

    Science.gov (United States)

    Chang, Kai; Xia, Yuanqing; Huang, Kaoli

    2016-01-01

    This paper considers the artificial potential field method combined with rotational vectors for a general problem of multi-unmanned aerial vehicle (UAV) systems tracking a moving target in dynamic three-dimensional environment. An attractive potential field is generated between the leader and the target. It drives the leader to track the target based on the relative position of them. The other UAVs in the formation are controlled to follow the leader by the attractive control force. The repulsive force affects among the UAVs to avoid collisions and distribute the UAVs evenly on the spherical surface whose center is the leader-UAV. Specific orders or positions of the UAVs are not required. The trajectories of avoidance obstacle can be obtained through two kinds of potential field with rotation vectors. Every UAV can choose the optimal trajectory to avoid the obstacle and reconfigure the formation after passing the obstacle. Simulations study on UAV are presented to demonstrate the effectiveness of proposed method.

  15. Event-Based Control Strategy for Mobile Robots in Wireless Environments.

    Science.gov (United States)

    Socas, Rafael; Dormido, Sebastián; Dormido, Raquel; Fabregas, Ernesto

    2015-12-02

    In this paper, a new event-based control strategy for mobile robots is presented. It has been designed to work in wireless environments where a centralized controller has to interchange information with the robots over an RF (radio frequency) interface. The event-based architectures have been developed for differential wheeled robots, although they can be applied to other kinds of robots in a simple way. The solution has been checked over classical navigation algorithms, like wall following and obstacle avoidance, using scenarios with a unique or multiple robots. A comparison between the proposed architectures and the classical discrete-time strategy is also carried out. The experimental results shows that the proposed solution has a higher efficiency in communication resource usage than the classical discrete-time strategy with the same accuracy.

  16. Association of plant injury with an air contaminant in a controlled environment facility

    Energy Technology Data Exchange (ETDEWEB)

    Knudson, L.L.; Tibbitts, T.W.

    1974-01-01

    Gaseous compounds are common, yet seldom recognized contaminants in controlled environments. Injury to several plant species has been observed in the Biotron which uses trichloroethylene as a coolant in its centrally controlled system. Sometimes this compound is present in the rooms at an average level of 2 ppm, as measured by gas chromatography. Injury symptoms, which vary between species, are characteristic of air pollution injury. Present studies with Tagetes patula show a distinctive necrosis on the upper leaf surfaces. Experiments are being conducted to determine whether trichloroethylene is the agent involved and to investigate aspects of the physiology of injury utilizing a procedure which may be applicable to other long-term, low-level pollution studies.

  17. Optimal operating policy for a controllable queueing model with a fuzzy environment

    Institute of Scientific and Technical Information of China (English)

    Chuen-homg LIN; Jau-chuan KE

    2009-01-01

    We construct the membership functions of the fuzzy objective values of a controllable queueing model, in which cost elements, arrival rate and service rate are all fuzzy numbers. Based on Zadeh's extension principle, a set of parametric nonlinear programs is developed to find the upper and lower bounds of the minimal average total cost per unit time at the possibility level. The membership functions of the minimal average total cost are further constructed using different values of the possibility level. A numerical example is solved successfully to illustrate the validity of the proposed approach. Because the object value is ex-pressed and governed by the membership functions, the optimization problem in a fuzzy environment for the controllable queueing models is represented more accurately and analytical results are more useful for system designers and practitioners.

  18. Bacteriophages for detection and control of bacterial pathogens in food and food-processing environment.

    Science.gov (United States)

    Brovko, Lubov Y; Anany, Hany; Griffiths, Mansel W

    2012-01-01

    This chapter presents recent advances in bacteriophage research and their application in the area of food safety. Section 1 describes general facts on phage biology that are relevant to their application for control and detection of bacterial pathogens in food and environmental samples. Section 2 summarizes the recently acquired data on application of bacteriophages to control growth of bacterial pathogens and spoilage organisms in food and food-processing environment. Section 3 deals with application of bacteriophages for detection and identification of bacterial pathogens. Advantages of bacteriophage-based methods are presented and their shortcomings are discussed. The chapter is intended for food scientist and food product developers, and people in food inspection and health agencies with the ultimate goal to attract their attention to the new developing technology that has a tremendous potential in providing means for producing wholesome and safe food.

  19. Virtual- and real-world operation of mobile robotic manipulators: integrated simulation, visualization, and control environment

    Science.gov (United States)

    Chen, ChuXin; Trivedi, Mohan M.

    1992-03-01

    This research is focused on enhancing the overall productivity of an integrated human-robot system. A simulation, animation, visualization, and interactive control (SAVIC) environment has been developed for the design and operation of an integrated robotic manipulator system. This unique system possesses the abilities for multisensor simulation, kinematics and locomotion animation, dynamic motion and manipulation animation, transformation between real and virtual modes within the same graphics system, ease in exchanging software modules and hardware devices between real and virtual world operations, and interfacing with a real robotic system. This paper describes a working system and illustrates the concepts by presenting the simulation, animation, and control methodologies for a unique mobile robot with articulated tracks, a manipulator, and sensory modules.

  20. Event-Based Control Strategy for Mobile Robots in Wireless Environments

    Science.gov (United States)

    Socas, Rafael; Dormido, Sebastián; Dormido, Raquel; Fabregas, Ernesto

    2015-01-01

    In this paper, a new event-based control strategy for mobile robots is presented. It has been designed to work in wireless environments where a centralized controller has to interchange information with the robots over an RF (radio frequency) interface. The event-based architectures have been developed for differential wheeled robots, although they can be applied to other kinds of robots in a simple way. The solution has been checked over classical navigation algorithms, like wall following and obstacle avoidance, using scenarios with a unique or multiple robots. A comparison between the proposed architectures and the classical discrete-time strategy is also carried out. The experimental results shows that the proposed solution has a higher efficiency in communication resource usage than the classical discrete-time strategy with the same accuracy. PMID:26633412

  1. SENVM: Server Environment Monitoring and Controlling System for a Small Data Center Using Wireless Sensor Network

    CERN Document Server

    Choochaisri, Supasate; Jenjaturong, Saran; Intanagonwiwat, Chalermek; Ratanamahatana, Chotirat Ann

    2011-01-01

    In recent years, efficient energy utilization becomes an essential requirement for data centers, especially in data centers of world-leading companies, where "Green Data Center" defines a new term for an environment-concerned data center. Solutions to change existing a data center to the green one may vary. In the big company, high-cost approaches including re-planning server rooms, changing air-conditioners, buying low-powered servers, and equipping sophisticating environmental control equipments are possible, but not for small to medium enterprises (SMEs) and academic sectors which have limited budget. In this paper, we propose a novel system, SENVM, used to monitor and control air temperature in a server room to be in appropriate condition, not too cold, where very unnecessary cooling leads to unnecessary extra electricity expenses, and also inefficient in energy utilization. With implementing on an emerging technology, Wireless Sensor Network (WSN), Green Data Center is feasible to every small data center...

  2. Can modifications to the bedroom environment improve the sleep of new parents? Two randomized controlled trials.

    Science.gov (United States)

    Lee, Kathryn A; Gay, Caryl L

    2011-02-01

    Postpartum sleep disruption is common among new parents. In this randomized controlled trial we evaluated a modified sleep hygiene intervention for new parents (infant proximity, noise masking, and dim lighting) in anticipation of night-time infant care. Two samples of new mothers (n = 118 and 122) were randomized to the experimental intervention or attention control, and sleep was assessed in late pregnancy and first 3 months postpartum using actigraphy and the General Sleep Disturbance Scale. The sleep hygiene strategies evaluated did not benefit the more socioeconomically advantaged women or their partners in Sample 1, but did improve postpartum sleep among the less advantaged women of Sample 2. Simple changes to the bedroom environment can improve sleep for new mothers with few resources.

  3. EEG-based asynchronous BCI control of a car in 3D virtual reality environments

    Institute of Scientific and Technical Information of China (English)

    ZHAO QiBin; ZHANG LiQing; CICHOCKI Andrzej

    2009-01-01

    Brain computer interface (BCl) aims at creating new communication channels without depending on brain's normal output channels of peripheral nerves and muscles.However,natural and sophisticated interactions manner between brain and computer still remain challenging.In this paper,we investigate how the duration of event-related desynchronization/synchronization (ERD/ERS) caused by motor im-agery (MI) can be modulated and used as an additional control parameter beyond simple binary deci-sions.Furthermore,using the non-time-locked properties of sustained (de)synchronization,we have developed an asynchronous BCl system for driving a car in 3D virtual reality environment (VRE) based on cumulative incremental control strategy.The extensive real time experiments confirmed that our new approach is able to drive smoothly a virtual car within challenging VRE only by the MI tasks with-out involving any muscular activities.

  4. Active member vibration control experiment in a KC-135 reduced gravity environment

    Science.gov (United States)

    Lawrence, C. R.; Lurie, B. J.; Chen, G.-S.; Swanson, A. D.

    1991-01-01

    An active member vibration control experiment in a KC-135 reduced gravity environment was carried out by the Air Force Flight Dynamics Laboratory and the Jet Propulsion Laboratory. Two active members, consisting of piezoelectric actuators, displacement sensors, and load cells, were incorporated into a 12-meter, 104 kg box-type test structure. The active member control design involved the use of bridge (compound) feedback concept, in which the collocated force and velocity signals are feedback locally. An impact-type test was designed to accommodate the extremely short duration of the reduced gravity testing window in each parabolic flight. The moving block analysis technique was used to estimate the modal frequencies and dampings from the free-decay responses. A broadband damping performance was demonstrated up to the ninth mode of 40 Hz. The best damping performance achieved in the flight test was about 5 percent in the fourth mode of the test structure.

  5. Event-Based Control Strategy for Mobile Robots in Wireless Environments

    Directory of Open Access Journals (Sweden)

    Rafael Socas

    2015-12-01

    Full Text Available In this paper, a new event-based control strategy for mobile robots is presented. It has been designed to work in wireless environments where a centralized controller has to interchange information with the robots over an RF (radio frequency interface. The event-based architectures have been developed for differential wheeled robots, although they can be applied to other kinds of robots in a simple way. The solution has been checked over classical navigation algorithms, like wall following and obstacle avoidance, using scenarios with a unique or multiple robots. A comparison between the proposed architectures and the classical discrete-time strategy is also carried out. The experimental results shows that the proposed solution has a higher efficiency in communication resource usage than the classical discrete-time strategy with the same accuracy.

  6. Heat dissipation in controlled environment enclosures through the application of water screens

    Science.gov (United States)

    Warrington, I. J.; Halligan, E. A.; Ruby, L. C.; Mcnaughton, K. G.

    1994-01-01

    The use of plate glass-water thermal barriers in controlled environment facilities effectively reduces the thermal load within the plant growth chamber. This allows high PPFs to be provided for plant growth and development studies, adequate simulation of daily light integrals, and simulation of peak PPF's. Further, substantial amounts of incandescent lamp supplementation can be used to achieve simulation of daylight R:FR ratios which are needed to ensure adequate stem development in some species. While the focus in this paper is on the use of entire thermal barriers which separate the lighting enclosure from the plant growth chamber, the same principles apply to the use of water jackets for cooling individual lamps (such as can occur with xenon-arc lamps). In this instance, the barrier separating the lamps from the plant chamber can be much simpler (e.g., plexiglass) as the main function of the barrier is to separate the air ventilation of the lamp enclosure from the air system within the plant growth chamber. The main advantage of water as a thermal barrier is the negligible absorption of radiation in the photosynthetically-active and near infrared wavebands. Consequently, plate glass-water barriers typically allow transmission of approximately 90% of radiation in these regions. While ventilated double and triple glazing systems appear to be attractive alternative to water barriers from an operating standpoint, their significant absorption in the biologically-important wavebands (7 - 12%) with each glass layer and longer-wave cut-offs (typically 2500 - 4000 nm) makes them a much less attractive alternative. The data presented here demonstrate clearly that measurement of PPF alone is not an adequate representation of the radiation environment being used in a controlled environment study. The amounts and proportions of long-wave and short-wave radiation in a plant growth chamber are dependent on lamp type, lamp combination, presence of a thermal barrier, the type of

  7. Emergent adaptive behaviour of GRN-controlled simulated robots in a changing environment

    Directory of Open Access Journals (Sweden)

    Yao Yao

    2016-12-01

    Full Text Available We developed a bio-inspired robot controller combining an artificial genome with an agent-based control system. The genome encodes a gene regulatory network (GRN that is switched on by environmental cues and, following the rules of transcriptional regulation, provides output signals to actuators. Whereas the genome represents the full encoding of the transcriptional network, the agent-based system mimics the active regulatory network and signal transduction system also present in naturally occurring biological systems. Using such a design that separates the static from the conditionally active part of the gene regulatory network contributes to a better general adaptive behaviour. Here, we have explored the potential of our platform with respect to the evolution of adaptive behaviour, such as preying when food becomes scarce, in a complex and changing environment and show through simulations of swarm robots in an A-life environment that evolution of collective behaviour likely can be attributed to bio-inspired evolutionary processes acting at different levels, from the gene and the genome to the individual robot and robot population.

  8. Analysis, testing, and control of telescope's high-precision drive system in low-temperature environment

    Science.gov (United States)

    Du, Fu-Jia; Zhang, Jian; Wen, Hai-Kun

    2014-07-01

    Antarctic is perfect site for astronomic observatory. But Antarctic also challenge the telescope design because of low temperature. The low temperature can impact characterization of telescope control system, especially for drive system. The following phenomenon can be produced due to low temperature. 1. The viscosity of grease will increase. 2. The clearance of bearing and gear will decrease. These two factors can lead to the increase in load torque of drive system with temperature drop. This would cause the bad tracking accuracy and low speed creeping. In order to overcome the impact of low temperature and improve the telescope's track accuracy. In this paper, we describe some methods to overcome the effect of low temperature. First, the motor's electromagnetism and lubrication in low temperature are analyzed. It shows that motor's electromagnetism is little affected by temperature if the suitable material is selected. But the characterization of grease change dramatically with temperature. Second, the other lubricant material, solid lubricant, instead of lubricating grease is proposed. Contrasting experiment on two lubricant material proved that the solid lubricant is better than lubricating grease in low temperature environment. Third, besides the mechanical solution, a method from control point view is proposed to reduce the temperature influence. In this paper, the friction feedforward algorithm is used to compensate the torque change. Laboratory testing results will be presented verifying that friction feedforward can increase the tracking accuracy in low temperature environment.

  9. Controlling cooperativity of a metastable open system coupled weakly to a noisy environment

    Institute of Scientific and Technical Information of China (English)

    赵阳

    2015-01-01

    The notion of cooperativity comprises a specific characteristic of a multipartite system concerning its ability to demon-strate a sigmoidal-type response of varying sensitivities to input stimuli in transitions between states under controlled con-ditions. From a statistical physics viewpoint, in this work we attempt to describe the cooperativity by the stability of a metastable open system with respect to irreversibility. To treat the evolution of a system weakly coupled to the environment in a kinetic framework, we consider two fluctuating energy levels of different dimensionalities, initial population of one level, reversible transitions of population between the levels, and irreversible depopulation of another level. An average is made over level fluctuations and environment vibrations so that inter-level transition rate can be obtained accounting for the influences of external control on level position and dimensionality. It is found that the cooperativity of the two-level system is bounded approximately between 0.736 and unity, with the lower bound indicating worsening system stability.

  10. Controlling cooperativity of a metastable open system coupled weakly to a noisy environment

    Science.gov (United States)

    Victor, I. Teslenko; Oleksiy, L. Kapitanchuk; Zhao, Yang

    2015-02-01

    The notion of cooperativity comprises a specific characteristic of a multipartite system concerning its ability to demonstrate a sigmoidal-type response of varying sensitivities to input stimuli in transitions between states under controlled conditions. From a statistical physics viewpoint, in this work we attempt to describe the cooperativity by the stability of a metastable open system with respect to irreversibility. To treat the evolution of a system weakly coupled to the environment in a kinetic framework, we consider two fluctuating energy levels of different dimensionalities, initial population of one level, reversible transitions of population between the levels, and irreversible depopulation of another level. An average is made over level fluctuations and environment vibrations so that an inter-level transition rate can be obtained accounting for the influences of external control on level position and dimensionality. It is found that the cooperativity of the two-level system is bounded approximately between 0.736 and unity, with the lower bound indicating worsening system stability. Project supported by the National Academy of Sciences of Ukraine (Grant No. 0110U007542) and the National Research Foundation of Singapore through the Competitive Research Programme (Grant No. NRF-CRP5-2009-04).

  11. Review of bioaerosols in indoor environment with special reference to sampling, analysis and control mechanisms.

    Science.gov (United States)

    Ghosh, Bipasha; Lal, Himanshu; Srivastava, Arun

    2015-12-01

    Several tiny organisms of various size ranges present in air are called airborne particles or bioaerosol which mainly includes live or dead fungi and bacteria, their secondary metabolites, viruses, pollens, etc. which have been related to health issues of human beings and other life stocks. Bio-terror attacks in 2001 as well as pandemic outbreak of flue due to influenza A H1N1 virus in 2009 have alarmed us about the importance of bioaerosol research. Hence characterization i.e. identification and quantification of different airborne microorganisms in various indoor environments is necessary to identify the associated risks and to establish exposure threshold. Along with the bioaerosol sampling and their analytical techniques, various literatures revealing the concentration levels of bioaerosol have been mentioned in this review thereby contributing to the knowledge of identification and quantification of bioaerosols and their different constituents in various indoor environments (both occupational and non-occupational sections). Apart from recognition of bioaerosol, developments of their control mechanisms also play an important role. Hence several control methods have also been briefly reviewed. However, several individual levels of efforts such as periodic cleaning operations, maintenance activities and proper ventilation system also serve in their best way to improve indoor air quality.

  12. Selection of anthracnose resistant common beans using detached leaves in partially controlled environment

    Directory of Open Access Journals (Sweden)

    Alisson Campos Pereira

    2014-08-01

    Full Text Available The objectives of this study were to evaluate the possibility of selecting anthracnose resistant common bean plants using detached primary leaves in partially controlled environment of a greenhouse and identify differences in the reaction of genotypes to anthracnose. The common bean cultivars Ouro Negro, OuroVermelho, ManteigãoFosco 11, Rudá, Rudá-R, VP8, BRSMG Madrepérola, Pérola, MeiaNoite and BRSMG Talismãwere characterizedfor resistance to the races 65, 81 and 453 of Colletotrichum lindemuthianum and the method of detached primary leaves was compared to the method with the traditional inoculation of plants at the phenological stage V2. The lines Rudá, Rudá-R and Pérola were inoculated with the races 65 and 453 of C. lindemuthianum, aiming to assess the rate of coincidence of anthracnose severity by both inoculation methods. In general, the two methods presented similar results for the reaction of the cultivars. The use of detached primary leaves of common bean plants in the partially controlled environment was feasible for selection of plants resistant to anthracnose and has the advantages of low-needed infrastructure and reduction of resources, space and time.

  13. Determining biodegradability of plastic materials under controlled and natural composting environments.

    Science.gov (United States)

    Mohee, R; Unmar, G

    2007-01-01

    With the advent of recently promulgated Government regulations on plastics in Mauritius, a study was initiated to examine the biodegradability of two different types of plastic, namely Willow Ridge Plastics - PDQ-H additive (Plastic A) and Ecosafe Plastic - TDPA additive (Plastic B) under controlled and natural composting environments. The results obtained from the controlled composting environment showed that the cumulative carbon dioxide evolution for Plastic A was much higher than that for Plastic B. Plastic A therefore showed a higher level of biodegradation in terms of CO2 evolution than Plastic B. However, from the regression analysis, it was found that the level of CO2 varying with time fitted the sigmoid type curves with very high correlation coefficients (R2 values: 0.9928, 0.9921 and 0.9816, for reference material, inoculum and Plastic A, respectively). The corresponding F-values obtained from the ANOVA analysis together with significance levels of pbiodegradability experiment were significant. The other experiment was undertaken to observe any physical change of Plastics A and B as compared to a reference plastic, namely, compostable plastic bag (Mater-Bi product-Plastic C), when exposed to a natural composting environment. Thermophilic temperatures were obtained for about 3-5 days of composting and the moisture content was in the range of 60-80% throughout the degradation process. It was observed that after 55 days of composting, Plastic C degraded completely while Plastic A and Plastic B did not undergo any significant degradation. It can be concluded that naturally based plastic made of starch would degrade completely in a time frame of 60 days, whereas plastics with biodegradable additive would require a longer time.

  14. Teacher Pupil-Control Ideology and Behavior as Predictors of Classroom Environment: Public and Catholic Schools Compared. Draft.

    Science.gov (United States)

    Lunenburg, Fred C.

    This study examined differences between public and Catholic schools concerning teachers' pupil control ideology, teachers' pupil control behavior, and students' perceptions of their classroom environments. The concepts of humanistic and custodial pupil control ideologies were used to contrast types of individual orientations and the types of…

  15. Chaos synchronization in noisy environment using nonlinear filtering and sliding mode control

    Energy Technology Data Exchange (ETDEWEB)

    Behzad, Mehdi [Center of Excellence in Design, Robotics, and Automation (CEDRA), Department of Mechanical Engineering, Sharif University of Technology, Postal Code 11365-9567, Azadi Avenue, Tehran (Iran, Islamic Republic of)], E-mail: m_behzad@sharif.edu; Salarieh, Hassan [Center of Excellence in Design, Robotics, and Automation (CEDRA), Department of Mechanical Engineering, Sharif University of Technology, Postal Code 11365-9567, Azadi Avenue, Tehran (Iran, Islamic Republic of)], E-mail: salarieh@mech.sharif.edu; Alasty, Aria [Center of Excellence in Design, Robotics, and Automation (CEDRA), Department of Mechanical Engineering, Sharif University of Technology, Postal Code 11365-9567, Azadi Avenue, Tehran (Iran, Islamic Republic of)], E-mail: aalasti@sharif.edu

    2008-06-15

    This paper presents an algorithm for synchronizing two different chaotic systems, using a combination of the extended Kalman filter and the sliding mode controller. It is assumed that the drive chaotic system has a random excitation with a stochastically chaotic behavior. Two different cases are considered in this study. At first it is assumed that all state variables of the drive system are available, i.e. complete state measurement, and a sliding mode controller is designed for synchronization. For the second case, it is assumed that the output of the drive system does not contain the whole state variables of the drive system, and it is also affected by some random noise. By combination of extended Kalman filter and the sliding mode control, a synchronizing control law is proposed. As a case study, the presented algorithm is applied to the Lur'e-Genesio chaotic systems as the drive-response dynamic systems. Simulation results show the good performance of the algorithm in synchronizing the chaotic systems in presence of noisy environment.

  16. Vibration, buckling and smart control of microtubules using piezoelectric nanoshells under electric voltage in thermal environment

    Science.gov (United States)

    Farajpour, A.; Rastgoo, A.; Mohammadi, M.

    2017-03-01

    Piezoelectric nanomaterials such as zinc oxide (ZnO) are of low toxicity and have many biomedical applications including optical imaging, drug delivery, biosensing and harvesting biomechanical energy using hybrid nanogenerators. In this paper, the vibration, buckling and smart control of microtubules (MTs) embedded in an elastic medium in thermal environment using a piezoelectric nanoshell (PNS) are investigated. The MT and PNS are considered to be coupled by a filament network. The PNS is subjected to thermal loads and an external electric voltage which operates to control the mechanical behavior of the MT. Using the nonlocal continuum mechanics, the governing differential equations are derived. An exact solution is presented for simply supported boundary conditions. The differential quadrature method is also used to solve the governing equations for other boundary conditions. A detailed parametric study is conducted to investigate the effects of the elastic constants of surrounding medium and internal filament matrix, scale coefficient, electric voltage, the radius-to-thickness ratio of PNSs and temperature change on the smart control of MTs. It is found that the applied electric voltage can be used as an effective controlling parameter for the vibration and buckling of MTs.

  17. Vibration, buckling and smart control of microtubules using piezoelectric nanoshells under electric voltage in thermal environment

    Energy Technology Data Exchange (ETDEWEB)

    Farajpour, A., E-mail: ariobarzan.oderj@gmail.com; Rastgoo, A.; Mohammadi, M.

    2017-03-15

    Piezoelectric nanomaterials such as zinc oxide (ZnO) are of low toxicity and have many biomedical applications including optical imaging, drug delivery, biosensing and harvesting biomechanical energy using hybrid nanogenerators. In this paper, the vibration, buckling and smart control of microtubules (MTs) embedded in an elastic medium in thermal environment using a piezoelectric nanoshell (PNS) are investigated. The MT and PNS are considered to be coupled by a filament network. The PNS is subjected to thermal loads and an external electric voltage which operates to control the mechanical behavior of the MT. Using the nonlocal continuum mechanics, the governing differential equations are derived. An exact solution is presented for simply supported boundary conditions. The differential quadrature method is also used to solve the governing equations for other boundary conditions. A detailed parametric study is conducted to investigate the effects of the elastic constants of surrounding medium and internal filament matrix, scale coefficient, electric voltage, the radius-to-thickness ratio of PNSs and temperature change on the smart control of MTs. It is found that the applied electric voltage can be used as an effective controlling parameter for the vibration and buckling of MTs.

  18. Multilingual home environment and specific language impairment: a case-control study in Chinese children.

    Science.gov (United States)

    Cheuk, Daniel Ka Leung; Wong, Virginia; Leung, Gabriel Matthew

    2005-07-01

    Specific language impairment (SLI) is a common developmental disorder in young children. To investigate the association between multilingual home environment and SLI, we conducted a case-control study in Hong Kong Chinese children over a 4-year period in the Duchess of Kent Children's Hospital. Consecutive medical records of all new referrals below 5 years of age were reviewed and children diagnosed with SLI (case) were compared with those referred with other developmental and behavioural problems who had been assessed as having normal language and overall development (control) using the Griffiths Mental Developmental Scale. SLI was defined as those with a language quotient more than one standard deviation below the mean and below the general developmental quotient in children with normal general developmental quotient, but without neurological or other organic diseases. We used binary and ordinal logistic regression to assess any association between SLI and multilingual exposure at home, adjusting for age and gender of subjects, parental age, education level and occupational status, number of siblings, family history of language delay and main caregiver at home. Multivariable linear regression was used to examine the effect of covariates on the language comprehension and expression standard scores assessed by the Reynell Developmental Language Scale. A total of 326 cases and 304 controls were included. The mean ages of cases and controls were 2.56 and 2.89 years respectively. Boys predominated in both groups (cases, 75.2%; controls, 60.2%). The children were exposed to between one and four languages at home, the major ones being Cantonese Chinese followed by English. The adjusted odds ratio (OR) of SLI was 2.94; [95% confidence interval (CI) 1.82, 4.74] for multilingual compared with monolingual exposure. A significant linear dose-response relationship was found (OR of SLI = 2.58 [1.72, 3.88] for each additional language to which the child was exposed). Male

  19. The function of green belt Jatibarang as quality control for the environment of Semarang city

    Science.gov (United States)

    Murtini, Titien Woro; Harani, Arnis Rochma; Ernadia, Loretta

    2017-06-01

    The quality of the healthy environment in a neighborhood city is decreasing in number. According to the government regulation, Act No. 26 of 2007, a city should have 20% of green areas from the total area of the city. Now, Semarang only has 7.5% of green areas from the total city area. One of the efforts made by the Government of Semarang is the establishment of a greenbelt in Jatibarang area. It consists of several parts, namely, the reservoirs in the green belt area and also the plant zone in other sectors. The reservoir has a function as the controller of water resources sustainability where the crops serve as the balance for the combination. Thus, it is interesting to study how the interplay of these two functions in a green belt area. The primary data used in this study was obtained from the locus of research by direct observation, interview, and physical data collection. Based on the data collection, data was then processed and analyzed in accordance with the indicators that had been compiled based on theories of reservoirs, green belts, and the quality of the urban environment. Government regulations regarding with the greenbelt and tanks were also used as references in the discussion. The research found out that the presence of the reservoir and the plants in the green belt of Jatibarang can improve the function of the green belt optimally which is a real influence for the improvement of the environment quality, especially water. The Greenbelt was divided into four zones, namely the Arboretum, Argo - Forestry, Ecotourism, Buffer - Zone also made the region became a beautiful greenbelt that brought a positive influence to environmental quality.

  20. A controlled laboratory environment to study EO signal degradation due to underwater turbulence

    Science.gov (United States)

    Matt, Silvia; Hou, Weilin; Goode, Wesley; Liu, Guigen; Han, Ming; Kanaev, Andrey; Restaino, Sergio

    2015-05-01

    Temperature microstructure in the ocean can lead to localized changes in the index of refraction and can distort underwater electro-optical (EO) signal transmission. A similar phenomenon is well-known from atmospheric optics and generally referred to as "optical turbulence". Though turbulent fluctuations in the ocean distort EO signal transmission and can impact various underwater applications, from diver visibility to active and passive remote sensing, there have been few studies investigating the subject. To provide a test bed for the study of impacts from turbulent flows on underwater EO signal transmission, and to examine and mitigate turbulence effects, we set up a laboratory turbulence environment allowing the variation of turbulence intensity. Convective turbulence is generated in a large Rayleigh- Bénard tank and the turbulent flow is quantified using high-resolution Acoustic Doppler Velocimeter profilers and fast thermistor probes. The turbulence measurements are complemented by computational fluid dynamics simulations of convective turbulence emulating the tank environment. These numerical simulations supplement the sparse laboratory measurements. The numerical data compared well to the laboratory data and both conformed to the Kolmogorov spectrum of turbulence and the Batchelor spectrum of temperature fluctuations. The controlled turbulence environment can be used to assess optical image degradation in the tank in relation to turbulence intensity, as well as to apply adaptive optics techniques. This innovative approach that combines optical techniques, turbulence measurements and numerical simulations can help understand how to mitigate the effects of turbulence impacts on underwater optical signal transmission, as well as advance optical techniques to probe oceanic processes.

  1. Implementing Iris in the Railway Control Office Application for Secure Saas in Cloud Environment

    Directory of Open Access Journals (Sweden)

    Dr. K. Meena

    2015-12-01

    Full Text Available Technology plays a vital role in each and every part of the world. In particular ―Cloud‖ computing - a moderately recent term, characterizes the path to develop the advancement in the world of computer science. Further, Cloud provides an affordable environment for its users through different forms of services such as SaaS (Software as a service, PaaS (Platform as a service, and IaaS (Infrastructure as a Service. Cloud computing is also an Internet-based computing where a large pool of systems are connected in private or public networks, and provide dynamically scalable infrastructure for application data as well as file storage. Security of Cloud computing is an evolving sub-domain of network security, computer security and information security. In spite of its advantages, Cloud environment has many security flaws such as loss of important data, data leakage and something related to cloning, resource pooling etc. Security of Cloud Computing is an emerging area for study. It includes several security and privacy issues with challenges and solutions for many security issues of cloud computing. The Control Office Application (COA is the latest addition to train operations related IT application of Indian Railways. Along with the Freight Operations Information System (FOIS, COA has led to a complete transformation in train operations and facilitates all information on train operations being computer generated. It is this application that feeds the National Train Enquiry System (NTES which provides passengers with up to date information on train running. COA also provides train operations information to FOIS and ICMS. The objective of the Indian Railways is to further improve the operations by using technological aids that enable quicker data capture and intelligent applications that provide better planning and forecasting tools. To overcome these issues, in Cloud computing, we can use SaaS (software as a service. In this paper, we have proposed

  2. Understanding and controlling airborne organic compounds in the indoor environment: mass transfer analysis and applications.

    Science.gov (United States)

    Zhang, Y; Xiong, J; Mo, J; Gong, M; Cao, J

    2016-02-01

    Mass transfer is key to understanding and controlling indoor airborne organic chemical contaminants (e.g., VVOCs, VOCs, and SVOCs). In this study, we first introduce the fundamentals of mass transfer and then present a series of representative works from the past two decades, focusing on the most recent years. These works cover: (i) predicting and controlling emissions from indoor sources, (ii) determining concentrations of indoor air pollutants, (iii) estimating dermal exposure for some indoor gas-phase SVOCs, and (iv) optimizing air-purifying approaches. The mass transfer analysis spans the micro-, meso-, and macroscales and includes normal mass transfer modeling, inverse problem solving, and dimensionless analysis. These representative works have reported some novel approaches to mass transfer. Additionally, new dimensionless parameters such as the Little number and the normalized volume of clean air being completely cleaned in a given time period were proposed to better describe the general process characteristics in emissions and control of airborne organic compounds in the indoor environment. Finally, important problems that need further study are presented, reflecting the authors' perspective on the research opportunities in this area.

  3. Extended Queue Management Backward Congestion Control Algorithms for Web Transfers in Wireless Environment

    Directory of Open Access Journals (Sweden)

    V.Sinthu Janita Prakash

    2012-10-01

    Full Text Available Wireless links are characterized by high error rates and intermittent connectivity. TCP congestion control has been developed on the assumption that network congestion is the only cause for packet loss. Upon detecting a packet loss, TCP drops its transmit window resulting in an unnecessary reduction of end-to-end throughput which results in suboptimal performance.The sender has to be made aware by some feedback mechanism that some of the losses reported are not due to congestion. The Active Queue Management algorithms (AQM are used to reduce congestion, and in this paper, we have analysed four AQM algorithms, Random Early Deduction (RED, Wireless Explicit Congestion Notification (WECN, Queue Management Backward Congestion Control Algorithm (QMBCCA and its enhanced version Extended Queue Management Backward Congestion Control Algorithm (EQMBCCA. WECN, QMBCCA & EQMBCCA algorithms make use of feedback mechanisms. WECN gives feedback using the CE bit. QMBCCA and EQMBCCA make use of ISQ notifications and also the CE bit whenever the average queue size crosses minimum threshold value. EQMBCCA reduces the reverse ISQ traffic by introducing a configurable intermediate threshold value IntThres. The comparison is made in terms of Delay, HTTP packet loss percentage and fairness for FTP flows in a wireless environment. It is found that the performance of EQMBCCA is almost equal to that of QMBCCA and better than RED and WECN.

  4. Institutional Level Identity Control Strategies in the Distance Education Environment: A Survey of Administrative Staff

    Directory of Open Access Journals (Sweden)

    Alexander Amigud

    2013-12-01

    Full Text Available Physical separation of students and instructors creates the gap of anonymity and limited control over the remote learning environment. The ability of academic institutions to authenticate students and validate authorship of academic work at various points during a course is necessary for preserving not only perceived credibility but also public safety. With the growing scope of distance education programs that permeate critical areas such as healthcare, airspace, water management, and food solutions, universities have a moral obligation to employ secure measures to verify learning outcomes. This study examines the measures universities with large distance education programs employ to align identity of learners with the academic work they do, as well as the effectiveness of and challenges and barriers to their implementation. The research was undertaken using a multiple case approach and examined survey responses from five academic administrators at five officially accredited post secondary institutions in three countries. The cases examined in the study include: Athabasca University, Open University UK, Penn State University World Campus, University of Maryland University College, and eConcordia, Concordia University’s distance learning facility. This study is not an exhaustive attempt to examine all aspects of academic integrity, but rather to create awareness about various learner authentication strategies. This study confirms that secure learner authentication in the distance education environment is possible. However, with greater pressure to enhance security of learner authentication, the openness of open learning is challenged and may change as we know it.

  5. Management of Rett Syndrome in the Controlled Multisensory (Snoezelen Environment. A Review with Three Case Stories

    Directory of Open Access Journals (Sweden)

    Meir Lotan

    2006-01-01

    Full Text Available Rett syndrome (RS is a neurological disorder resulting from an X-linked dominant mutation. It is characterized by a variety of physical and perceptual disabilities, resulting in a need for continuous intervention programs to be administered on a regular basis throughout life. Many of these individuals with RS show fear of movement and, therefore, find it hard to accept external facilitation (so common in physical therapy intervention. In a search for novel intervention techniques that might improve their ability to cope with difficulties in daily situations, while also reducing their difficulty in handling motion inflicted by an external physical facilitator, we examined the use of the Snoezelen room. The Snoezelen, also known as the controlled multisensory environment, can provide a soothing atmosphere that appeals to the individual with RS, while at the same time it can improve physical, sensorial, and functional abilities. This article suggests various intervention goals that are appropriate for individuals with RS at different stages of the disorder. Since the management of young children with RS in the multisensory environment has been discussed at length in the past, this article will mainly describe intervention with adults with RS, focusing on three case stories. The present article reviews the available scientific materials on the topic of Snoezelen, incorporating clinical knowledge in the field of RS and suggesting this approach as an appropriate intervention method for this population.

  6. Design of Wireless Sensor Network-Based Greenhouse Environment Monitoring and Automatic Control System

    Directory of Open Access Journals (Sweden)

    Yongxian Song

    2012-05-01

    Full Text Available  In view of the characteristics of greenhouse environment monitoring system, a system scheme based on wireless sensor network (WSN is presented, which adopts Atmega128L chip and CC2530 that is a low power RF chip from TI to design the sink node and sensor nodes in the WSN. The monitoring and management center can control the temperature and humidity of the greenhouse, measure the carbon dioxide content, and collect the information about intensity of illumination, and so on. And the system adopts multilevel energy memory. It combines energy management with energy transfer, which makes the energy collected by solar energy batteries be used reasonably. Therefore, the self-managing energy supply system is established. In addition, the nodes deployment method and time synchronization problem are analyzed in detail. The system can solve the problem of complex cabling with the advantages of low power consumption, low cost, good robustness, extended flexible and high reliability. An effective tool is provided for monitoring and analysis decision-making of the greenhouse environment.

  7. Mapping Thermal Habitat of Ectotherms Based on Behavioral Thermoregulation in a Controlled Thermal Environment

    Science.gov (United States)

    Fei, T.; Skidmore, A.; Liu, Y.

    2012-07-01

    Thermal environment is especially important to ectotherm because a lot of physiological functions rely on the body temperature such as thermoregulation. The so-called behavioural thermoregulation function made use of the heterogeneity of the thermal properties within an individual's habitat to sustain the animal's physiological processes. This function links the spatial utilization and distribution of individual ectotherm with the thermal properties of habitat (thermal habitat). In this study we modelled the relationship between the two by a spatial explicit model that simulates the movements of a lizard in a controlled environment. The model incorporates a lizard's transient body temperatures with a cellular automaton algorithm as a way to link the physiology knowledge of the animal with the spatial utilization of its microhabitat. On a larger spatial scale, 'thermal roughness' of the habitat was defined and used to predict the habitat occupancy of the target species. The results showed the habitat occupancy can be modelled by the cellular automaton based algorithm at a smaller scale, and can be modelled by the thermal roughness index at a larger scale.

  8. Applying physicochemical approaches to control phosphogypsum heavy metal releases in aquatic environment.

    Science.gov (United States)

    Ammar, Rawaa; El Samrani, Antoine G; Kazpard, Véronique; Bassil, Joseph; Lartiges, Bruno; Saad, Zeinab; Chou, Lei

    2013-12-01

    One of the most important sources of solid waste in the Mediterranean Basin ecosystem originated from the phosphate fertilizer industries, which discharge phosphogypsum (PG) directly into aquatic environments or are stacked on stockpiles. The present study investigates metal release from PG under the influence of variable pH, increasing PG mass content, and complexing organic matter ligands. Major ions from PG leachates, grain size and charge, main functional groups along with metal leachability (Pb, Cd, Cr, Cu, and Zn) were determined using ion chromatography, laser diffraction, zetameter, Fourier transform infrared spectroscopy, and atomic absorption spectroscopy, respectively. The complete dissolution of PG recorded is at 2 g/L. Saturation and supersaturation with respect to PG may occur at concentrations of 3 and 4 g/L, respectively, revealing a clustering phenomenon leading to heavy metal encapsulation within the aggregates. Organic ligands such as citrate may trigger the cationic exchange within the PG suspension leading to ion release. As these factors are considered as specific process involving the release of contaminants from PG during storage under natural conditions, this study could set the foundations for PG remediation in aquatic environment. Organic ligands under controlled pH conditions could be utilized in treating fertilizer industrial wastes by taking into consideration the particularity of the receiving area, thus decreasing metal hazardous impact on natural media.

  9. [The use of thermoelectric modules (Peltier elements) in the relative humidity control of a hyperbaric environment].

    Science.gov (United States)

    Stashkov, O A

    2002-01-01

    The author considers an option for automatic relative humidity control of a hyperbaric environment demonstrated in a pressure chamber for small animals. To achieve the purpose, a device has been developed to cool off gas mixture using the Peltier effect and then remove condensate. Experiments were performed with two different gas mixtures: O2-N2-He at 25.5 x 10(5) Pa and 30 degrees C and air at 6.9 x 10(5) Pa and 22 degrees C. The device enabled stabilization of relative humidity in the chamber at 30-40% without bio-objects and at 35-46% with bio-objects (Wistar rats).

  10. SOLERAS - Solar Controlled Environment Agriculture Project. Final report, Volume 5. Science Applications, Incorporated system requirements definition

    Energy Technology Data Exchange (ETDEWEB)

    1985-01-01

    This report sets forth the system requirements for a Solar Controlled-Environment Agriculture System (SCEAS) Project. In the report a conceptual baseline system description for an engineering test facility is given. This baseline system employs a fluid roof/roof filter in combination with a large storage tank and a ground water heat exchanger in order to provide cooling and heating as needed. Desalination is accomplished by pretreatment followed by reverse osmosis. Energy is provided by means of photovoltaics and wind machines in conjunction with storage batteries. Site and climatic data needed in the design process are given. System performance specifications and integrated system design criteria are set forth. Detailed subsystem design criteria are presented and appropriate references documented.

  11. Behavior of QQ-plots and genomic control in studies of gene-environment interaction.

    Directory of Open Access Journals (Sweden)

    Arend Voorman

    Full Text Available Genome-wide association studies of gene-environment interaction (GxE GWAS are becoming popular. As with main effects GWAS, quantile-quantile plots (QQ-plots and Genomic Control are being used to assess and correct for population substructure. However, in G x E work these approaches can be seriously misleading, as we illustrate; QQ-plots may give strong indications of substructure when absolutely none is present. Using simulation and theory, we show how and why spurious QQ-plot inflation occurs in G x E GWAS, and how this differs from main-effects analyses. We also explain how simple adjustments to standard regression-based methods used in G x E GWAS can alleviate this problem.

  12. Project Scheduling Using Hybrid Genetic Algorithm with Fuzzy Logic Controller in SCM Environment

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    In supply chain management (SCM) environment, we consider a resource-constrained project scheduling problem (rcPSP) model as one of advanced scheduling problems considered by a constraint programming technique. We develop a hybrid genetic algorithm (hGA) with a fuzzy logic controller (FLC) to solve the rcPSP which is the well known NP-hard problem. This new approach is based on the design of genetic operators with FLC through initializing the serial method which is superior for a large rcPSP scale. For solving these rcPSP problems, we first demonstrate that our hGA with FLC (flc-hGA) yields better results than several heuristic procedures presented in the literature. We have revealed a fact that flc-hGA has the evolutionary behaviors of average fitness better than hGA without FLC.

  13. Short-term genome evolution of Listeria monocytogenes in a non-controlled environment

    Directory of Open Access Journals (Sweden)

    Ivy Reid A

    2008-11-01

    Full Text Available Abstract Background While increasing data on bacterial evolution in controlled environments are available, our understanding of bacterial genome evolution in natural environments is limited. We thus performed full genome analyses on four Listeria monocytogenes, including human and food isolates from both a 1988 case of sporadic listeriosis and a 2000 listeriosis outbreak, which had been linked to contaminated food from a single processing facility. All four isolates had been shown to have identical subtypes, suggesting that a specific L. monocytogenes strain persisted in this processing plant over at least 12 years. While a genome sequence for the 1988 food isolate has been reported, we sequenced the genomes of the 1988 human isolate as well as a human and a food isolate from the 2000 outbreak to allow for comparative genome analyses. Results The two L. monocytogenes isolates from 1988 and the two isolates from 2000 had highly similar genome backbone sequences with very few single nucleotide (nt polymorphisms (1 – 8 SNPs/isolate; confirmed by re-sequencing. While no genome rearrangements were identified in the backbone genome of the four isolates, a 42 kb prophage inserted in the chromosomal comK gene showed evidence for major genome rearrangements. The human-food isolate pair from each 1988 and 2000 had identical prophage sequence; however, there were significant differences in the prophage sequences between the 1988 and 2000 isolates. Diversification of this prophage appears to have been caused by multiple homologous recombination events or possibly prophage replacement. In addition, only the 2000 human isolate contained a plasmid, suggesting plasmid loss or acquisition events. Surprisingly, besides the polymorphisms found in the comK prophage, a single SNP in the tRNA Thr-4 prophage represents the only SNP that differentiates the 1988 isolates from the 2000 isolates. Conclusion Our data support the hypothesis that the 2000 human listeriosis

  14. Control of yellow and purple nutsedge in elevated CO2 environments with glyphosate and halosulfuron

    Directory of Open Access Journals (Sweden)

    Stephen Christopher Marble

    2015-01-01

    Full Text Available Atmospheric concentrations of carbon dioxide (CO2 have significantly increased over the past century and are expected to continue rising in the future. While elevated levels of CO2 will likely result in higher crop yields, weed growth is also highly likely to increase, which could increase the incidence of herbicide resistant biotypes. An experiment was conducted in 2012 to determine the effects of an elevated CO2 environment on glyphosate and halosulfuron efficacy for postemergence control of purple and yellow nutsedge (Cyperus rotundus L. and C. esculentus L.. Both species of nutsedge where grown in 3.0-L containers under either ambient or elevated (ambient + 200 µmol mol-1 CO2 in open-top field chambers and treated with either 0.5×, 1.0×, or 1.5× of the manufacturer’s labeled rate of halosulfuron, glyphosate, or a tank mix of the two herbicides. The growth of both nutsedge species responded positively to elevated CO2, purple nutsedge had increased shoot and root dry weights and yellow nutsedge had increased shoot, root, and tuber dry weights and counts. Few treatment differences were observed among the herbicides at any of the rates tested. At three weeks following herbicide application, both purple and yellow nutsedge were adequately controlled by both herbicides and combinations at all rates tested, regardless of CO2 concentration. Based on this study, it is likely that predicted future CO2 levels will have little impact on the efficacy of single applications of halosulfuron or glyphosate for control of purple and yellow nutsedge at the growth stages described here, although scenarios demanding more persistent control efforts remain a question.

  15. Control of yellow and purple nutsedge in elevated CO2 environments with glyphosate and halosulfuron.

    Science.gov (United States)

    Marble, S Christopher; Prior, Stephen A; Runion, G Brett; Torbert, H Allen

    2015-01-01

    Atmospheric concentrations of carbon dioxide (CO2) have significantly increased over the past century and are expected to continue rising in the future. While elevated levels of CO2 will likely result in higher crop yields, weed growth is also highly likely to increase, which could increase the incidence of herbicide resistant biotypes. An experiment was conducted in 2012 to determine the effects of an elevated CO2 environment on glyphosate and halosulfuron efficacy for postemergence control of purple and yellow nutsedge (Cyperus rotundus L. and C. esculentus L.). Both species of nutsedge where grown in 3.0-L containers under either ambient or elevated (ambient + 200 μmol mol(-1)) CO2 in open-top field chambers and treated with either 0.5×, 1.0×, or 1.5× of the manufacturer's labeled rate of halosulfuron, glyphosate, or a tank mix of the two herbicides. The growth of both nutsedge species responded positively to elevated CO2, purple nutsedge had increased shoot and root dry weights and yellow nutsedge had increased shoot, root, and tuber dry weights and counts. Few treatment differences were observed among the herbicides at any of the rates tested. At 3 weeks following herbicide application, both purple and yellow nutsedge were adequately controlled by both herbicides and combinations at all rates tested, regardless of CO2 concentration. Based on this study, it is likely that predicted future CO2 levels will have little impact on the efficacy of single applications of halosulfuron or glyphosate for control of purple and yellow nutsedge at the growth stages described here, although scenarios demanding more persistent control efforts remain a question.

  16. Self-paced brain-computer interface control of ambulation in a virtual reality environment

    Science.gov (United States)

    Wang, Po T.; King, Christine E.; Chui, Luis A.; Do, An H.; Nenadic, Zoran

    2012-10-01

    Objective. Spinal cord injury (SCI) often leaves affected individuals unable to ambulate. Electroencephalogram (EEG) based brain-computer interface (BCI) controlled lower extremity prostheses may restore intuitive and able-body-like ambulation after SCI. To test its feasibility, the authors developed and tested a novel EEG-based, data-driven BCI system for intuitive and self-paced control of the ambulation of an avatar within a virtual reality environment (VRE). Approach. Eight able-bodied subjects and one with SCI underwent the following 10-min training session: subjects alternated between idling and walking kinaesthetic motor imageries (KMI) while their EEG were recorded and analysed to generate subject-specific decoding models. Subjects then performed a goal-oriented online task, repeated over five sessions, in which they utilized the KMI to control the linear ambulation of an avatar and make ten sequential stops at designated points within the VRE. Main results. The average offline training performance across subjects was 77.2±11.0%, ranging from 64.3% (p = 0.001 76) to 94.5% (p = 6.26×10-23), with chance performance being 50%. The average online performance was 8.5±1.1 (out of 10) successful stops and 303±53 s completion time (perfect = 211 s). All subjects achieved performances significantly different than those of random walk (p ambulation after only 10 minutes training. The ability to achieve such BCI control with minimal training indicates that the implementation of future BCI-lower extremity prosthesis systems may be feasible.

  17. Tunable Diode Laser Sensor for Monitoring and Control of Harsh Combustion Environments

    Energy Technology Data Exchange (ETDEWEB)

    VonDrasek, William; Melsio-Pubill, Anna

    2006-05-30

    This work represents the collaborative effort between American Air Liquide and Physical Sciences, Inc. for developing a sensor based on near-IR tunable diode lasers (TDL). The multi-species capability of the sensor for simultaneous monitoring of CO, O2, and H2O concentration as well as gas temperature is ideal for in-situ monitoring on industrial furnaces. The chemical species targeted are fundamental for controlling the combustion space for improved energy efficiency, reduced pollutants, and improved product quality, when coupling the measurement to a combustion control system. Several add-on modules developed provide flexibility in the system configuration for handling different process monitoring applications. For example, the on-Demand Power Control system for the 1.5 ?m laser is used for high particle density exhaust streams where laser transmission is problematic. For long-distance signal collection a fiber optic communication system is used to reduce noise pick-up. Finally, hardened modules to withstand high ambient temperatures, immune to EMF interference, protection from flying debris, and interfaced with pathlength control laser beam shielding probes were developed specifically for EAF process monitoring. Demonstration of these different system configurations was conducted on Charter Steel's reheat furnace, Imco Recycling, Inc. (now Aleris International, Inc.) aluminum reverberatory furnace, and Gerdau Ameristeel's EAF. Measurements on the reheat furnace demonstrated zone monitoring with the measurement performed close to the steel billet. Results from the aluminum furnace showed the benefit of measuring in-situ near the bath. In this case, low-level furnace optimization was performed and demonstrated 5% fuel savings. Monitoring tests on the EAF off-gas demonstrated the level of industrialization of the sensor to survive the harsh EAF environment. Long-term testing on the EAF has been on-going for over 6 months with essentially zero maintenance

  18. Adaptation to a new environment allows cooperators to purge cheaters stochastically.

    Science.gov (United States)

    Waite, Adam James; Shou, Wenying

    2012-11-20

    Cooperation via production of common goods is found in diverse life forms ranging from viruses to social animals. However, natural selection predicts a "tragedy of the commons": Cheaters, benefiting from without producing costly common goods, are more fit than cooperators and should destroy cooperation. In an attempt to discover novel mechanisms of cheater control, we eliminated known ones using a yeast cooperator-cheater system engineered to supply or exploit essential nutrients. Surprisingly, although less fit than cheaters, cooperators quickly dominated a fraction of cocultures. Cooperators isolated from these cocultures were superior to the cheater isolates they had been cocultured with, even though these cheaters were superior to ancestral cooperators. Resequencing and phenotypic analyses revealed that evolved cooperators and cheaters all harbored mutations adaptive to the nutrient-limited cooperative environment, allowing growth at a much lower concentration of nutrient than their ancestors. Even after the initial round of adaptation, evolved cooperators still stochastically dominated cheaters derived from them. We propose the "adaptive race" model: If during adaptation to an environment, the fitness gain of cooperators exceeds that of cheaters by at least the fitness cost of cooperation, the tragedy of the commons can be averted. Although cooperators and cheaters sample from the same pool of adaptive mutations, this symmetry is soon broken: The best cooperators purge cheaters and continue to grow, whereas the best cheaters cause rapid self-extinction. We speculate that adaptation to changing environments may contribute to the persistence of cooperative systems before the appearance of more sophisticated mechanisms of cheater control.

  19. Voice Over Internet Protocol (VoIP) in a Control Center Environment

    Science.gov (United States)

    Pirani, Joseph; Calvelage, Steven

    2010-01-01

    The technology of transmitting voice over data networks has been available for over 10 years. Mass market VoIP services for consumers to make and receive standard telephone calls over broadband Internet networks have grown in the last 5 years. While operational costs are less with VoIP implementations as opposed to time division multiplexing (TDM) based voice switches, is it still advantageous to convert a mission control center s voice system to this newer technology? Marshall Space Flight Center (MSFC) Huntsville Operations Support Center (HOSC) has converted its mission voice services to a commercial product that utilizes VoIP technology. Results from this testing, design, and installation have shown unique considerations that must be addressed before user operations. There are many factors to consider for a control center voice design. Technology advantages and disadvantages were investigated as they refer to cost. There were integration concerns which could lead to complex failure scenarios but simpler integration for the mission infrastructure. MSFC HOSC will benefit from this voice conversion with less product replacement cost, less operations cost and a more integrated mission services environment.

  20. Mealtime family interactions in home environments of children with loss of control eating.

    Science.gov (United States)

    Czaja, Julia; Hartmann, Andrea Sabrina; Rief, Winfried; Hilbert, Anja

    2011-06-01

    Experimental and self-report studies have shown that parents have a strong influence on their normal or overweight children's eating behavior, i.e. through parental feeding behavior or communication. Studies in children with loss of control (LOC) eating that have investigated this relationship are scarce, and ecologically valid observational studies are missing. This study examined family functioning at mealtimes in home environments in 43 families of a child with LOC eating and 31 families of a child without LOC eating; the children were 8-13 years old. Familial interactions, child eating behavior, and parental mealtime behavior were assessed using the Mealtime Family Interaction Coding System, observation of bite speed of the child, and self-report questionnaires. Less healthy patterns of communication (U=201.53, pChildren with LOC eating (M=4.73, SD=1.88) ate faster than controls (M=3.71, SD=1.19; pchildren and are associated with the child's eating behavior. Parent-child communication training should be tested as an intervention for children with LOC episodes.

  1. Integration of herbicides with manual weeding for controlling the weeds in rice under saline environment.

    Science.gov (United States)

    Hakim, M A; Juraimi, Abdul Shukor; Hanafi, M M; Rafii, Mohd Y; Ismail, Mohd Razi; Karim, S M Rezaul; Kausar, H

    2015-11-01

    The pot experiment was conducted to select appropriate integrated weed management method in rice under different salinity levels (0, 4 and 8 dS m(-1)). All the parameters including rice and weed measured were significantly influenced by weed control treatments at all salinity levels. Treatments including weed-free condition, Pretilachlor @0.375 kg ai ha(-1) + hand weeding, Propanil + Thiobencarb @ 0.9 kg ai ha(-1) and 1.8 kg ai ha(-1)+ hand weeding performed better under all salinity levels. Pretilachlor @ 0.375 kg ai ha(-1) with one round of hand weeding and propanil + thiobencarb 0.9 kg ai ha(-1) + 1.8 kg ai ha(-1) with one round of hand weeding were comparable to weed-free yields, and were superior to other treatments under salinity condition. Considering all the parameters, pretilachlor @ 0.375 kg ai ha(-1) + one round of hand weeding (at 65 DAT), propanil + thiobencarb 0.9 kg ai ha(-1) +1.8 kg ai ha(-1) + one round of hand weeding (at 65 DAT) gave the most effective control of weeds in rice under saline environments.

  2. Control strategies for a stochastic model of host-parasite interaction in a seasonal environment.

    Science.gov (United States)

    Gómez-Corral, A; López García, M

    2014-08-01

    We examine a nonlinear stochastic model for the parasite load of a single host over a predetermined time interval. We use nonhomogeneous Poisson processes to model the acquisition of parasites, the parasite-induced host mortality, the natural (no parasite-induced) host mortality, and the reproduction and death of parasites within the host. Algebraic results are first obtained on the age-dependent distribution of the number of parasites infesting the host at an arbitrary time t. The interest is in control strategies based on isolation of the host and the use of an anthelmintic at a certain intervention instant t0. This means that the host is free living in a seasonal environment, and it is transferred to a uninfected area at age t0. In the uninfected area, the host does not acquire new parasites, undergoes a treatment to decrease the parasite load, and its natural and parasite-induced mortality are altered. For a suitable selection of t0, we present two control criteria that appropriately balance effectiveness and cost of intervention. Our approach is based on simple probabilistic principles, and it allows us to examine seasonal fluctuations of gastrointestinal nematode burden in growing lambs.

  3. Plant diversity effects on ecosystem evapotranspiration and carbon uptake: a controlled environment (Ecotron) and modeling approach

    Science.gov (United States)

    Milcu, Alexandru; Roy, Jacques

    2016-04-01

    Effects of species and functional diversity of plants on ecosystem evapotranspiration and carbon fluxes have been rarely assessed simultaneously. Here we present the results from an experiment that combined a lysimeter setup in a controlled environment facility (Ecotron) with large ecosystem samples/ monoliths originating from a long-term biodiversity experiment ("The Jena Experiment") and a modelling approach. We aimed at (1) quantifying the impact of plant species richness (4 vs. 16 species) on day- and night-time ecosystem water vapor fluxes and carbon uptake, (2) partitioning ecosystem evapotranspiration into evaporation and plant transpiration using the Shuttleworth and Wallace (SW) energy partitioning model, and (3) identifying the most parsimonious predictors of water vapor vapor and CO2 fluxes using plant functional trait-based metrics such as functional diversity and community weighted means. The SW model indicated that at low plant species richness, a higher proportion of the available energy was diverted to evaporation (a non-productive flux), while at higher species richness the proportion of ecosystem transpiration (a production-related water flux) increased. This led to an increased carbon gain per amount of water vapor loss (i.e. increased water use efficiency). While the LAI controlled the carbon and water fluxes, we also found that the diversity of plant functional traits, and in particular of leaf nitrogen concentration are potential important predictors of ecosystem transpiration and carbon uptake and consequently significantly contributed to increase in water use efficiency in communities with higher plant diversity.

  4. A programming environment to control switching networks based on STC104 packet routing chip

    Science.gov (United States)

    Legrand, I. C.; Schwendicke, U.; Leich, H.; Medinnis, M.; Koehler, A.; Wegner, P.; Sulanke, K.; Dippel, R.; Gellrich, A.

    1997-02-01

    The software environment used to control a large switching architecture based on SGS-Thomson STC104 (an asynchronous 32-way dynamic packet routing chip) is presented. We are evaluating this switching technology for large scale, real-time parallel systems. A Graphical User Interface (GUI) written as a multi-thread application in Java allows to set the switch configuration and to continuously monitor the state of each link. This GUI connects to a multi-thread server via TCP/IP sockets. The server is running on a PC-Linux system and implements the virtual channel protocol in communicating with the STC104 switching units using the Data Strobe link or the VME bus. Linux I/O drivers to control the Data Strobe link parallel adaptor (STC101) were developed. For each client the server creates a new thread and allocates a new socket for communications. The Java code of the GUI may be transferred to any client using the http protocol providing a user friendly interface to the system with real-time monitoring which is also platform independent.

  5. A Learning Model for Enhancing the Student's Control in Educational Process Using Web 2.0 Personal Learning Environments

    Science.gov (United States)

    Rahimi, Ebrahim; van den Berg, Jan; Veen, Wim

    2015-01-01

    In recent educational literature, it has been observed that improving student's control has the potential of increasing his or her feeling of ownership, personal agency and activeness as means to maximize his or her educational achievement. While the main conceived goal for personal learning environments (PLEs) is to increase student's control by…

  6. A Learning Model for Enhancing the Student's Control in Educational Process Using Web 2.0 Personal Learning Environments

    Science.gov (United States)

    Rahimi, Ebrahim; van den Berg, Jan; Veen, Wim

    2015-01-01

    In recent educational literature, it has been observed that improving student's control has the potential of increasing his or her feeling of ownership, personal agency and activeness as means to maximize his or her educational achievement. While the main conceived goal for personal learning environments (PLEs) is to increase student's control by…

  7. Power to the People: Using Learner Control to Improve Trainee Reactions and Learning in Web-Based Instructional Environments

    Science.gov (United States)

    Orvis, Karin A.; Fisher, Sandra L.; Wasserman, Michael E.

    2009-01-01

    This experimental study investigated the mechanisms by which learner control influences learning in an e-learning environment. The authors hypothesized that learner control would enhance learning indirectly through its effect on trainee reactions and learner engagement (in particular, off-task attention), such that learners who were more satisfied…

  8. Biogeochemical and hydrological controls in mobilizing Se in a saline wetland environment

    Science.gov (United States)

    Datta, S.; Hettiarachchi, G. M.; Crawford, M.; Karna, R.; Allmendinger, N. E.; Khatiwada, R.

    2010-12-01

    Selenium (Se) contamination in watersheds remains a challenge to water and land and wildlife managers throughout the west and mid west of US. In that sense, understanding the fundamentals of Se mobilization, fixation and bioconcentration is the current research endeavor. The challenge for Se research is developing watershed-geochemical models that are well founded in Se geochemical/biologcial principles that can be applied in a wide range of situations to inform decisions. Pariette Wetlands, a 9000 acre Bureau of Land Management controlled wetland system composed of 20 ponds located at the confluence of Pariette Draw and the Green River is the present location of this study. The agricultural and irrigation practices and the water-rock interactions leading to salinization can be associated with changes in Se chemistry in the rivers. Since its inception Pariette Wetlands has been home to a rich and diverse wetland ecosystem located in the arid Uintah Basin of Northeastern Utah. Detailed sampling of surficial sediments (0-1 m) from stream banks, channel beds and for water sampling have been undergone in 2 separate field trips throughout the entire reach of the wetland. To establish Pariette Draw’s contribution of Se to the Green river, water and sediments were also sampled from the Green River up and downstream of its confluence with Pariette Draw. In situ measurements of water parameters within the wetland suggest a clear trend of increased pH from upstream, 8, to downstream, 9.2 and combined with TDS suggest a pH controlled saline environment system. The headwaters near Flood Control Dam have an added input of Se from a possible irrigation source upstream in Pleasant Valley area while Se drastically decreases downstream towards the Red Head Pond. Se fractionation in sediments is being analyzed via a sequential extraction procedure to locate the labile fractions of mostly inorganic bound Se. Solid state speciation of Se via μ-XRF aided μ-XANES is being combined

  9. A Cost Effective Solution for Development Environment for Data Acquisition, Monitoring and Simulation of PLC Controlled Applications

    Directory of Open Access Journals (Sweden)

    O. Bjelica

    2014-06-01

    Full Text Available It is very important to test and monitor the operation of Programmable Logic Controller (PLC in real time (online. Nowadays, conventional, but expensive monitoring systems for PLCs, such as Supervisory Control and Data Acquisition (SCADA systems, software and hardware simulators (or debuggers, are widely used. This paper proposes a user friendly and cost-effective development environment for monitoring, data acquisition and online simulation of applications with PLC. The purpose of this solution is to simulate the process which is controlled by the PLC. The performances of the proposed development environment are presented on the examples of washing machine and dishwasher simulators.

  10. Autonomy supported, learner-controlled or system-controlled learning in hypermedia environments and the influence of academic self-regulation style

    NARCIS (Netherlands)

    Gorissen, Chantal J J; Kester, Liesbeth; Brand-Gruwel, Saskia; Martens, Rob

    2015-01-01

    This study focuses on learning in three different hypermedia environments that either support autonomous learning, learner-controlled learning or system-controlled learning and explores the mediating role of academic self-regulation style (ASRS; i.e. a macro level of motivation) on learning. This re

  11. Autonomy Supported, Learner-Controlled or System-Controlled Learning in Hypermedia Environments and the Influence of Academic Self-Regulation Style

    Science.gov (United States)

    Gorissen, Chantal J. J.; Kester, Liesbeth; Brand-Gruwel, Saskia; Martens, Rob

    2015-01-01

    This study focuses on learning in three different hypermedia environments that either support autonomous learning, learner-controlled learning or system-controlled learning and explores the mediating role of academic self-regulation style (ASRS; i.e. a macro level of motivation) on learning. This research was performed to gain more insight in the…

  12. Autonomy supported, learner-controlled or system-controlled learning in hypermedia environments and the influence of academic self-regulation style

    NARCIS (Netherlands)

    Gorissen, Chantal J J; Kester, Liesbeth; Brand-Gruwel, Saskia; Martens, Rob

    2015-01-01

    This study focuses on learning in three different hypermedia environments that either support autonomous learning, learner-controlled learning or system-controlled learning and explores the mediating role of academic self-regulation style (ASRS; i.e. a macro level of motivation) on learning. This

  13. Controlling transfer of quantum correlations among bi-partitions of a composite quantum system by combining different noisy environments

    Institute of Scientific and Technical Information of China (English)

    Zhang Xiu-Xing; LiFu-Li

    2011-01-01

    The correlation dynamics are investigated for various bi-partitions of a composite quantum system consisting of two qubits and two independent and non-identical noisy environments.The two qubits have no direct interaction with each other and locally interact with their environments.Classical and quantum correlations including the entanglement are initially prepared only between the two qubits.We find that contrary to the identical noisy environment case,the quantum correlation transfer direction can be controlled by combining different noisy environments.The amplitudedamping environment determines whether there exists the entanglement transfer among bi-partitions of the system.When one qubit is coupled to an amplitude-damping environment and the other one to a bit-flip one,we find a very interesting result that all the quantum and the classical correlations,and even the entanglement,originally existing between the qubits,can be completely transferred without any loss to the qubit coupled to the bit-flit environment and the amplitude-damping environment.We also notice that it is possible to distinguish the quantum correlation from the classical correlation and the entanglement by combining different noisy environments.

  14. Effects of light quality on the accumulation of phytochemicals in vegetables produced in controlled environments: a review.

    Science.gov (United States)

    Bian, Zhong Hua; Yang, Qi Chang; Liu, Wen Ke

    2015-03-30

    Phytochemicals in vegetables are important for human health, and their biosynthesis, metabolism and accumulation are affected by environmental factors. Light condition (light quality, light intensity and photoperiod) is one of the most important environmental variables in regulating vegetable growth, development and phytochemical accumulation, particularly for vegetables produced in controlled environments. With the development of light-emitting diode (LED) technology, the regulation of light environments has become increasingly feasible for the provision of ideal light quality, intensity and photoperiod for protected facilities. In this review, the effects of light quality regulation on phytochemical accumulation in vegetables produced in controlled environments are identified, highlighting the research progress and advantages of LED technology as a light environment regulation tool for modifying phytochemical accumulation in vegetables. © 2014 Society of Chemical Industry.

  15. Controlling Aedes aegypti in Cryptic Environments with Manually Carried Ultra-Low Volume and Mist Blower Pesticide Applications.

    Science.gov (United States)

    Harwood, James F; Helmey, Wendy L; Turnwall, Brent B; Justice, Kevin D; Farooq, Muhammed; Richardson, Alec G

    2016-09-01

    Because Aedes aegypti , a vector of dengue, chikungunya, and Zika viruses, exhibits resting and reproductive behaviors that present challenges to control them, pesticide application equipment available for vector control must be evaluated for their ability to control this species in a variety of cryptic environments. Five types of pesticide sprayers, representing 3 spray technologies (1 mister, 2 ultra-low volume [ULV] cold foggers, and 2 ULV thermal foggers), were evaluated for their ability to control adult and immature stages of Ae. aegypti in indoor and outdoor environments. Cages holding adult mosquitoes and larvae were placed in cryptic sites for indoor sprays and placed among dense vegetation for outdoor sprays. Adult and pupal mortality data were recorded following applications of a mixture of synergized pyrethrins and pyriproxyfen. We found that no single sprayer was best suited for controlling Ae. aegypti in indoor and outdoor environments, nor was one best for controlling adult and immature mosquitoes. Sprayers producing larger droplets (misters and cold foggers) were more effective in controlling immature mosquitoes indoors and outdoors. Thermal fogging was more effective in controlling adults indoors, whereas cold fogs and misters were more effective for outdoor control.

  16. Effects of Home Visitation on Maternal Competencies, Family Environment, and Child Development: a Randomized Controlled Trial.

    Science.gov (United States)

    Sierau, Susan; Dähne, Verena; Brand, Tilman; Kurtz, Vivien; von Klitzing, Kai; Jungmann, Tanja

    2016-01-01

    Based on the US Nurse-Family Partnership (NFP) program, the German home visiting program "Pro Kind" offered support for socially and financially disadvantaged first-time mothers from pregnancy until the children's second birthday. A multi-centered, longitudinal randomized controlled trial (RCT) was conducted to assess its effectiveness on mothers and children. A total of 755 women with multiple risk factors were recruited, 394 received regular home visits (treatment group), while 361 only had access to standard community services (control group). Program influences on family environment (e.g., quality of home, social support), maternal competencies (e.g., maternal self-efficacy, empathy, parenting style), and child development (e.g., cognitive and motor development) were assessed from mothers' program intake in pregnancy to children's second birthday based on self-reports in regular interviews and developmental tests. Generalized estimating equations (GEE) models showed small, but significant positive treatment effects on parental self-efficacy, and marginally significant effects on social support, and knowledge on child rearing. Maternal stress, self-efficacy, and feelings of attachment in the TG tend to show a more positive development over time. Subgroup effects were found for high-risk mothers in the TG, who reported more social support over time and, generally, had children with higher developmental scores compared to their CG counterparts. Post hoc analyses of implementation variables revealed the quality of the helping relationship as a significant indicator of treatment effects. Results are discussed in terms of implementation and public policy differences between NFP and Pro Kind.

  17. Controls on Arsenic Retention in Surface and Subsurface Environments: Resolving the Impact of Iron Reduction

    Science.gov (United States)

    Tufano, K.; Fendorf, S.

    2007-12-01

    A transition from oxidizing to reducing conditions has long been implicated in increasing aqueous As concentrations. Confounding processes controlling the release of As, reductive transformation of ferrihydrite, a common Fe(III) (hydr)oxide, has recently been shown to promote As retention rather than release. Elucidating the processes controlling As desorption and subsequent migration in surface and subsurface environments and how environmental factors (for example, availability of labile carbon and duration/extent of flooding) affect these processes will allow predictions to be made regarding long-term stability of As in soil and sediment. In turn, this can aid in evaluating the likelihood of having measurable As in groundwater. To better resolve these processes, here we examine As desorption from ferrihydrite-coated sands pre-sorbed with As(III) at circumneutral pH under Fe-reducing conditions with the dissimilatory iron reducing bacterium (DIRB) Shewanella putrefaciens strain CN- 32. We reveal that upon iron reduction, transformation of As-bearing ferrihydrite results in As(III) retention. However, over time there is a shift from reductive transformation to reductive dissolution of the As-bearing Fe phase(s) coupled with prolonged release of As to the aqueous phase. Our results suggest that arsenic retention may increase or decrease depending on the type of iron oxide, secondary iron transformations, and duration of reducing conditions. Immediately following a transition to anaerobic conditions there is potential for As retention on newly formed ferric/ferrous (hydr)oxide phases; however prolonged reduction will result in both the dissolution of ferric/ferrous (hydr)oxides and release of aqueous arsenic.

  18. Application of overlay modeling and control with Zernike polynomials in an HVM environment

    Science.gov (United States)

    Ju, JaeWuk; Kim, MinGyu; Lee, JuHan; Nabeth, Jeremy; Jeon, Sanghuck; Heo, Hoyoung; Robinson, John C.; Pierson, Bill

    2016-03-01

    Shrinking technology nodes and smaller process margins require improved photolithography overlay control. Generally, overlay measurement results are modeled with Cartesian polynomial functions for both intra-field and inter-field models and the model coefficients are sent to an advanced process control (APC) system operating in an XY Cartesian basis. Dampened overlay corrections, typically via exponentially or linearly weighted moving average in time, are then retrieved from the APC system to apply on the scanner in XY Cartesian form for subsequent lot exposure. The goal of the above method is to process lots with corrections that target the least possible overlay misregistration in steady state as well as in change point situations. In this study, we model overlay errors on product using Zernike polynomials with same fitting capability as the process of reference (POR) to represent the wafer-level terms, and use the standard Cartesian polynomials to represent the field-level terms. APC calculations for wafer-level correction are performed in Zernike basis while field-level calculations use standard XY Cartesian basis. Finally, weighted wafer-level correction terms are converted to XY Cartesian space in order to be applied on the scanner, along with field-level corrections, for future wafer exposures. Since Zernike polynomials have the property of being orthogonal in the unit disk we are able to reduce the amount of collinearity between terms and improve overlay stability. Our real time Zernike modeling and feedback evaluation was performed on a 20-lot dataset in a high volume manufacturing (HVM) environment. The measured on-product results were compared to POR and showed a 7% reduction in overlay variation including a 22% terms variation. This led to an on-product raw overlay Mean + 3Sigma X&Y improvement of 5% and resulted in 0.1% yield improvement.

  19. Electronic desalting for controlling the ionic environment in droplet-based biosensing platforms

    Energy Technology Data Exchange (ETDEWEB)

    Swaminathan, Vikhram Vilasur [Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Dak, Piyush; Alam, Muhammad A., E-mail: rbashir@illinois.edu, E-mail: alam@purdue.edu [School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Reddy, Bobby; Duarte-Guevara, Carlos; Zhong, Yu [Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Salm, Eric [Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Fischer, Andrew [Abbott Laboratories, 1921 Hurd Drive, Dept. 8482 LC2 M/S 2-33, Irving, Texas 75038 (United States); Liu, Yi-Shao [Taiwan Semiconductor Manufacturing Company, Hsinchu 300-78, Taiwan (China); Bashir, Rashid, E-mail: rbashir@illinois.edu, E-mail: alam@purdue.edu [Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States)

    2015-02-02

    The ability to control the ionic environment in saline waters and aqueous electrolytes is useful for desalination as well as electronic biosensing. We demonstrate a method of electronic desalting at micro-scale through on-chip micro electrodes. We show that, while desalting is limited in bulk solutions with unlimited availability of salts, significant desalting of ≥1 mM solutions can be achieved in sub-nanoliter volume droplets with diameters of ∼250 μm. Within these droplets, by using platinum-black microelectrodes and electrochemical surface treatments, we can enhance the electrode surface area to achieve >99% and 41% salt removal in 1 mM and 10 mM salt concentrations, respectively. Through self-consistent simulations and experimental measurements, we demonstrate that conventional double-layer theory over-predicts the desalting capacity and, hence, cannot be used to model systems that are mass limited or undergoing significant salt removal from the bulk. Our results will provide a better understanding of capacitive desalination, as well as a method for salt manipulation in high-throughput droplet-based microfluidic sensing platforms.

  20. Data link air traffic control and flight deck environments: Experiment in flight crew performance

    Science.gov (United States)

    Lozito, Sandy; Mcgann, Alison; Corker, Kevin

    1993-01-01

    This report describes an experiment undertaken in a full mission simulation environment to investigate the performance impact of, and human/system response to, data-linked Air Traffic Control (ATC) and automated flight deck operations. Subjects were twenty pilots (ten crews) from a major United States air carrier. Crews flew the Advanced Concepts Flight Simulator (ACFS), a generic 'glass cockpit' simulator at NASA Ames. The method of data link used was similar to the data link implementation plans for a next-generation aircraft, and included the capability to review ATC messages and directly enter ATC clearance information into the aircraft systems. Each crew flew experimental scenarios, in which data reflecting communication timing, errors and clarifications, and procedures were collected. Results for errors and clarifications revealed an interaction between communication modality (voice v. data link) and communication type (air/ground v. intracrew). Results also revealed that voice crews initiated ATC contact significantly more than data link crews. It was also found that data link crews performed significantly more extraneous activities during the communication task than voice crews. Descriptive data from the use of the review menu indicate the pilot-not-flying accessing the review menu most often, and also suggest diffulty in accessing the target message within the review menu structure. The overall impact of communication modality upon air/ground communication and crew procedures is discussed.

  1. Photodegradation of antibiotics on soil surfaces: laboratory studies on sulfadiazine in an ozone-controlled environment.

    Science.gov (United States)

    Wolters, André; Steffens, Markus

    2005-08-15

    Among the processes affecting transport and degradation of antibiotics released to the environment during application of manure and slurry to agricultural land, photochemical transformations are of particular interest. Drying-out of the top soil layer under field conditions enables sorption of surface-applied antibiotics to soil dust, thus facilitating direct, indirect, and sensitized photodegradation at the soil/atmosphere interface. For studying various photochemical transformation processes of sulfadiazine, a photovolatility chamber designed in accordance with the requirements of the USEPA Guideline and 161-3 was used. Application of 14C-labeled sulfadiazine enabled complete mass balances and allowed for investigating the impact of various surfaces (glass and soil dust) and environmental factors, i.e., irradiation and atmospheric ozone, on photodegradation and volatilization. Volatilization was shown to be a negligible process. Even after increasing the air temperature up to 35 degrees C only minor amounts of sulfadiazine and transformation products (0.01-0.28% of applied radioactivity) volatilized. Due to direct and indirect photodegradation, the highest extent of mineralization to 14CO2 (3.9%), the formation of degradation products and of nonextractable soil residues was measured in irradiated soil dust experiments using ozone concentrations of 200 ppb. However, even in the dark significant mineralization was observed when ozone was present, indicating ozone-controlled transformation of sulfadiazine to occur at the soil surface.

  2. Modelling and Control of Stepper Motors for High Accuracy Positioning Systems Used in Radioactive Environments

    CERN Document Server

    Picatoste Ruilope, Ricardo; Masi, Alessandro

    Hybrid Stepper Motors are widely used in open-loop position applications. They are the choice of actuation for the collimators in the Large Hadron Collider, the largest particle accelerator at CERN. In this case the positioning requirements and the highly radioactive operating environment are unique. The latter forces both the use of long cables to connect the motors to the drives which act as transmission lines and also prevents the use of standard position sensors. However, reliable and precise operation of the collimators is critical for the machine, requiring the prevention of step loss in the motors and maintenance to be foreseen in case of mechanical degradation. In order to make the above possible, an approach is proposed for the application of an Extended Kalman Filter to a sensorless stepper motor drive, when the motor is separated from its drive by long cables. When the long cables and high frequency pulse width modulated control voltage signals are used together, the electrical signals difer greatl...

  3. Experimental research on charging characteristics of a pressure-controlled VRLA battery in high-temperature environments

    Institute of Scientific and Technical Information of China (English)

    Hua ZHU; Jin-jun TAN; Zhang-lu XU; Ji-sen XU

    2009-01-01

    Valve-regulated-lead-acid (VRLA) battery charging performed in high-temperature environments is extremely risky under overcharge conditions, and may lead to a subsequent thermal runaway. A new pressure-controlled charging method was adopted and the charging characteristics of the pressure-controlled VRLA battery in high-temperature environments were ex-perimentally studied. The concept was tested in a large temperature gradient to obtain more details about the effects of users' accustomed charging and discharging modes on battery capacity.' The premature capacity loss (PCL) phenomenon under high temperature exposure was analyzed. The results showed that the capacity loss could be recovered by charging using a large current.

  4. Implementation of an Embedded Web Server Application for Wireless Control of Brain Computer Interface Based Home Environments.

    Science.gov (United States)

    Aydın, Eda Akman; Bay, Ömer Faruk; Güler, İnan

    2016-01-01

    Brain Computer Interface (BCI) based environment control systems could facilitate life of people with neuromuscular diseases, reduces dependence on their caregivers, and improves their quality of life. As well as easy usage, low-cost, and robust system performance, mobility is an important functionality expected from a practical BCI system in real life. In this study, in order to enhance users' mobility, we propose internet based wireless communication between BCI system and home environment. We designed and implemented a prototype of an embedded low-cost, low power, easy to use web server which is employed in internet based wireless control of a BCI based home environment. The embedded web server provides remote access to the environmental control module through BCI and web interfaces. While the proposed system offers to BCI users enhanced mobility, it also provides remote control of the home environment by caregivers as well as the individuals in initial stages of neuromuscular disease. The input of BCI system is P300 potentials. We used Region Based Paradigm (RBP) as stimulus interface. Performance of the BCI system is evaluated on data recorded from 8 non-disabled subjects. The experimental results indicate that the proposed web server enables internet based wireless control of electrical home appliances successfully through BCIs.

  5. Getting to the core of locus of control: Is it an evaluation of the self or the environment?

    Science.gov (United States)

    Johnson, Russell E; Rosen, Christopher C; Chang, Chu-Hsiang Daisy; Lin, Szu-Han Joanna

    2015-09-01

    Responding to criticisms surrounding the structural validity of the higher order core self-evaluations (CSE) construct, in the current study we examined the appropriateness of including locus of control as an indicator of CSE. Drawing from both theoretical and empirical evidence, we argue that locus of control is more heavily influenced by evaluations of the environment compared with the other CSE traits. Using data from 4 samples, we demonstrate that model fit for the higher order CSE construct is better when locus of control is excluded versus included as a trait indicator and that the shared variance between locus of control and CSE is nominal. This does not mean that locus of control is irrelevant for CSE theory though. We propose that evaluations of the environment moderate the relations that CSE has with its outcomes. To test this proposition, we collected data from 4 unique samples that included a mix of student and employee participants, self- and other-ratings, and cross-sectional and longitudinal data. Our results revealed that locus of control moderated relations of CSE with life and job satisfaction, and supervisor-rated job performance. CSE had stronger, positive relations with these outcomes when locus of control is internal versus external. These findings broaden CSE theory by demonstrating one way in which evaluations of the environment interface with evaluations of the self. (PsycINFO Database Record

  6. Real Time Implementation of PID and Fuzzy PD Controllers for DC-Servo Motor Based on Lab View Environment

    Directory of Open Access Journals (Sweden)

    Safaa M. Z. Al-Ubaidi

    2012-06-01

    Full Text Available This paper presents an implementation of conventional PID (CPID controller using Ziegler-Nichols rules and fuzzy PD (FPD controller for position servo motor control based on Lab View (Laboratory Virtual Instrument Engineering Workbench Environment through Data Acquisition (DAQ Device PCI- 6521 of National Instrument's and Data Acquisition Accessory Board Model (CB-68LP.CPID controller is perhaps the most well-known and most widely used in industrial applications. However, it has been known that CPID controller generally don’t work well for non-linear systems, higher order and time-delayed linear system and particularly complex and vague system. To overcome these difficulties, this paper proposes to use the FPD controller for a servo motor system instead of CPID. The parameters of servo motor used are completely unknown. The FPD structure has two-input single-output and fairly similar characteristic to its conventional counterpart and provides good performance. Simple rules base are used for FPD (nine rules only. Performance evaluation was carried out via a comparison study for the proposed control scheme and other existing control scheme, such as CPID controller. The critical point for this experiment on position system is a steady state error and settling time.  The performance showing that the FPD has less settling time and zero steady state error over its CPID. The algorithms of FPD and CPID controllers are implemented using PID, Fuzzy Logic and simulation toolkits of the Lab View environment.

  7. Suitability of Agent Technology for Military Command and Control in the Future Combat System Environment

    Energy Technology Data Exchange (ETDEWEB)

    Potok, TE

    2003-02-13

    The U.S. Army is faced with the challenge of dramatically improving its war fighting capability through advanced technologies. Any new technology must provide significant improvement over existing technologies, yet be reliable enough to provide a fielded system. The focus of this paper is to assess the novelty and maturity of agent technology for use in the Future Combat System (FCS). The FCS concept represents the U.S. Army's ''mounted'' form of the Objective Force. This concept of vehicles, communications, and weaponry is viewed as a ''system of systems'' which includes net-centric command and control (C{sup 2}) capabilities. This networked C{sup 2} is an important transformation from the historically centralized, or platform-based, C{sup 2} function since a centralized command architecture may become a decision-making and execution bottleneck, particularly as the pace of war accelerates. A mechanism to ensure an effective network-centric C{sup 2} capacity (combining intelligence gathering and analysis available at lower levels in the military hierarchy) is needed. Achieving a networked C{sup 2} capability will require breakthroughs in current software technology. Many have proposed the use of agent technology as a potential solution. Agents are an emerging technology, and it is not yet clear whether it is suitable for addressing the networked C{sup 2} challenge, particularly in satisfying battlespace scalability, mobility, and security expectations. We have developed a set of software requirements for FCS based on military requirements for this system. We have then evaluated these software requirements against current computer science technology. This analysis provides a set of limitations in the current technology when applied to the FCS challenge. Agent technology is compared against this set of limitations to provide a means of assessing the novelty of agent technology in an FCS environment. From this analysis we

  8. Human body micro-environment: The benefits of controlling airflow interaction

    DEFF Research Database (Denmark)

    Melikov, Arsen Krikor

    2015-01-01

    This paper focuses on the micro-environment around a human body, and especially on its interaction with the surrounding environment. Research on the free convection flow generated by a human body (including the convective boundary layer around the body and the thermal plume above the body), its...

  9. Circadian clock proteins control adaptation to novel environment and memory formation

    Science.gov (United States)

    A.Kondratova, Anna; V.Dubrovsky, Yuliya; Antoch, Marina P.; Kondratov, Roman V.

    2010-01-01

    Deficiency of the transcription factor BMAL1, a core component of the circadian clock, results in an accelerated aging phenotype in mice. The circadian clock regulates many physiological processes and was recently implicated in control of brain-based activities, such as memory formation and the regulation of emotions. Aging is accompanied by the decline in brain physiology, particularly decline in the response and adaptation to novelty. We investigated the role of the circadian clock in exploratory behavior and habituation to novelty using the open field paradigm. We found that mice with a deficiency of the circadian transcription factor BMAL1 display hyperactivity in novel environments and impaired intra- and intersession habituation, indicative of defects in short- and long-term memory formation. In contrast, mice double-deficient for the circadian proteins CRY1 and CRY2 (repressors of the BMAL1-mediated transcription) demonstrate reduced activity and accelerated habituation when compared to wild type mice. Mice with mutation in theClock gene (encoding the BMAL1 transcription partner) show normal locomotion, but increased rearing activity and impaired intersession habituation. BMAL1 is highly expressed in the neurons of the hippocampus - a brain region associated with spatial memory formation; BMAL1 deficiency disrupts circadian oscillation in gene expression and reactive oxygen species homeostasis in the brain, which may be among the possible mechanisms involved. Thus, we suggest that the BMAL1:CLOCK activity is critical for the proper exploratory and habituation behavior, and that the circadian clock prepares organism for a new round of everyday activities through optimization of behavioral learning. PMID:20519775

  10. Effect of climate change on infection of grapevine by downy and powdery mildew under controlled environment.

    Science.gov (United States)

    Pugliese, M; Gullino, M L; Garibaldi, A

    2011-01-01

    Plant responses to elevated CO2 and temperature have been much studied in recent years, but effects of climate change on pathological responses are largerly unknown. The pathosystems grapevine (Vitis vinifera) - downy mildew (Plasmopara viticola) and powdery mildew (Erysiphe necatrix) were chosen as models to assess the potential impact of increased CO2 and temperature on disease incidence and severity under controlled environment. Grapevine potted plants were grown in phytotrons under 4 different simulated climatic conditions: (1) standard temperature (ranging from 18 degrees to 22 degrees C) and standard CO2 concentration (450 ppm); (2) standard temperature and elevated CO2 concentration (800 ppm); (3) elevated temperature (ranging from 22 degrees to 26 degrees C, 4 degrees C higher than standard) and standard CO2 concentration; (4) elevated temperature and CO2 concentration. Each plant was inoculated with a spore suspension containing 5x10(5) cfu/ml. Disease index and physiological parameters (chlorophyll content, fluorescence, assimilation rate) were assessed. Results showed an increase of the chlorophyll content with higher temperatures and CO2 concentration, to which consequently corresponded an higher fluorescence index. Disease incidence of downy mildew increased when both CO2 and temperatures were higher, while an increase in CO2 did not influenced powdery mildew incidence, probably due to the increased photosynthetic activity of plants under such conditions. Considering that the rising concentrations of CO2 and other greenhouse gases will lead to an increase in global temperature and longer seasons, we can assume that this will allow more time for pathogens evolution and could increase pathogen survival, indirectly affecting downy and powdery mildews of grapevine.

  11. Toward Understanding Pore Formation and Mobility during Controlled Directional Solidification in a Microgravity Environment Investigation (PFMI)

    Science.gov (United States)

    Grugel, Richard N.; Anilkumar, A. V.; Luz, Paul; Jeter, Linda; Volz, Martin P.; Spivey, Reggie; Smith, G.

    2003-01-01

    The generation and inclusion of detrimental porosity, e.g., pipes and rattails can occur during controlled directional solidification processing. The origin of these defects is generally attributed to gas evolution and entrapment during solidification of the melt. On Earth, owing to buoyancy, an initiated bubble can rapidly rise through the liquid melt and pop at the surface; this is obviously not ensured in a low gravity or microgravity environment. Clearly, porosity generation and inclusion is detrimental to conducting any meaningful solidification-science studies in microgravity. Thus it is essential that model experiments be conducted in microgravity, to understand the details of the generation and mobility of porosity, so that methods can be found to eliminate it. In hindsight, this is particularly relevant given the results of the previous directional solidification experiments conducted in Space. The current International Space Station (ISS) Microgravity Science Glovebox (MSG) investigation addresses the central issue of porosity formation and mobility during controlled directional solidification processing in microgravity. The study will be done using a transparent metal-analogue material, succinonitrile (SCN) and succinonitrile-water 'alloys', so that direct observation and recording of pore generation and mobility can be made during the experiments. Succinonitrile is particularly well suited for the proposed investigation because it is transparent, it solidifies in a manner analogous to most metals, it has a convenient melting point, its material properties are well characterized and, it has been successfully used in previous microgravity experiments. The PFMI experiment will be launched on the UF-2, STS-111 flight. Highlighting the porosity development problem in metal alloys during microgravity processing, the poster will describe: (i) the intent of the proposed experiments, (ii) the theoretical rationale behind using SCN as the study material for

  12. Evaluating on-line control of goal-directed arm movement while standing in virtual visual environment

    OpenAIRE

    Martin, Olivier; Julian, Benjamin; Boissieux, Laurence; Gascuel, Jean-Dominique; Prablanc, Claude

    2002-01-01

    International audience; The control of visually guided movement has been showed to be optimised when motor programming quickly integrated the visual information to update on-going motor commands. The purpose of this study was to verify this proposition for movement executed in virtual visual environment (VE), by exploring the effect of immersion on the on-line visuomotor control of goal-directed arm movement. Six subjects participated in the experiment, in which hand reaching toward a station...

  13. Weathering and vegetation controls on nickel isotope fractionation in surface ultramafic environments (Albania)

    Science.gov (United States)

    Estrade, Nicolas; Cloquet, Christophe; Echevarria, Guillaume; Sterckeman, Thibault; Deng, Tenghaobo; Tang, YeTao; Morel, Jean-Louis

    2015-08-01

    The dissolved nickel (Ni) isotopic composition of rivers and oceans presents an apparent paradox. Even though rivers represent a major source of Ni in the oceans, seawater is more enriched in the heavier isotopes than river-water. Additional sources or processes must therefore be invoked to account for the isotopic budget of dissolved Ni in seawater. Weathering of continental rocks is thought to play a major role in determining the magnitude and sign of isotopic fractionation of metals between a rock and the dissolved product. We present a study of Ni isotopes in the rock-soil-plant systems of several ultramafic environments. The results reveal key insights into the magnitude and the control of isotopic fractionation during the weathering of continental ultramafic rocks. This study introduces new constraints on the influence of vegetation during the weathering process, which should be taken into account in interpretations of the variability of Ni isotopes in rivers. The study area is located in a temperate climate zone within the ophiolitic belt area of Albania. The serpentinized peridotites sampled present a narrow range of heavy Ni isotopic compositions (δ60Ni = 0.25 ± 0.16 ‰, 2SD n = 2). At two locations, horizons within two soil profiles affected by different degrees of weathering all presented light isotopic compositions compared to the parent rock (Δ60Nisoil-rock up to - 0.63 ‰). This suggests that the soil pool takes up the light isotopes, while the heavier isotopes remain in the dissolved phase. By combining elemental and mineralogical analyses with the isotope compositions determined for the soils, the extent of fractionation was found to be controlled by the secondary minerals formed in the soil. The types of vegetation growing on ultramafic-derived soils are highly adapted and include both Ni-hyperaccumulating species, which can accumulate several percent per weight of Ni, and non-accumulating species. Whole-plant isotopic compositions were found

  14. Feedback environment and well-being at work: The mediating role of personal control and feelings of helplessness

    NARCIS (Netherlands)

    Sparr, J.L.; Sonnentag, S.E.

    2008-01-01

    This study examines employees' personal control and feelings of helplessness at work as partial mediators of the relationship between the supervisor-employee feedback environment and well-being (job satisfaction, job depression, job anxiety, turnover intentions) at work. Findings are reported from a

  15. Observer-based scheme for tuning the control of variable speed wind turbines operating in hostile environments

    DEFF Research Database (Denmark)

    Caruana, Cedric; Al-Durra, Ahmed; Blaabjerg, Frede

    2016-01-01

    the control law. The proposed observer identifies variations in the power coefficient surface over time due to the effect of the environment on the rotor blades. Simulations for both open- and closed-loop operations are shown. The proposed technique shows the potential to alleviate the performance degradation...

  16. SOLERAS - Solar Controlled Environment Agriculture Project. Final report, Volume 4. Saudi Engineering Solar Energy Applications System Design Study

    Energy Technology Data Exchange (ETDEWEB)

    1985-01-01

    Literature summarizing a study on the Saudi Arabian solar controlled environment agriculture system is presented. Specifications and performance requirements for the system components are revealed. Detailed performance and cost analyses are used to determine the optimum design. A preliminary design of an engineering field test is included. Some weather data are provided for Riyadh, Saudi Arabia. (BCS)

  17. The complex logic of stringent response regulation in Caulobacter crescentus: starvation signalling in an oligotrophic environment.

    Science.gov (United States)

    Boutte, Cara C; Crosson, Sean

    2011-05-01

    Bacteria rapidly adapt to nutritional changes via the stringent response, which entails starvation-induced synthesis of the small molecule, ppGpp, by RelA/SpoT homologue (Rsh) enzymes. Binding of ppGpp to RNA polymerase modulates the transcription of hundreds of genes and remodels the physiology of the cell. Studies of the stringent response have primarily focused on copiotrophic bacteria such as Escherichia coli; little is known about how stringent signalling is regulated in species that live in consistently nutrient-limited (i.e. oligotrophic) environments. Here we define the input logic and transcriptional output of the stringent response in the oligotroph, Caulobacter crescentus. The sole Rsh protein, SpoT(CC), binds to and is regulated by the ribosome, and exhibits AND-type control logic in which amino acid starvation is a necessary but insufficient signal for activation of ppGpp synthesis. While both glucose and ammonium starvation upregulate the synthesis of ppGpp, SpoT(CC) detects these starvation signals by two independent mechanisms. Although the logic of stringent response control in C. crescentus differs from E. coli, the global transcriptional effects of elevated ppGpp are similar, with the exception of 16S rRNA transcription, which is controlled independently of spoT(CC). This study highlights how the regulatory logic controlling the stringent response may be adapted to the nutritional niche of a bacterial species.

  18. Controlling operational risk : concepts and practices : a participant-observer research on the development of concepts and practices in controlling operational risk in a banking environment

    NARCIS (Netherlands)

    Tillaart, van den Alice Hendrika Adriana Johanna

    2003-01-01

    The subject of this thesis is controlling operational risk in a banking environment. Operational risk is defined as ¿the risk of losses resulting from inadequate or failed internal processes, people, systems, or from external events¿. The definition already points out that this is a broad subject th

  19. Control of particle-spacecraft interactions in a LEO near-spacecraft environment

    Science.gov (United States)

    Conger, J. C.; Hastings, D. E.

    1993-01-01

    Spacecraft may actively modify their environment by the release of particulate contamination. Particles may also enter the near-spacecraft environment when spacecraft enter clouds of dust or debris in space. This contamination may seriously hamper the function of systems on board the craft. Particulate contamination in the vicinity of a spacecraft may interfere substantially with electromagnetic observations in the infrared, visible and ultraviolet regions of the spectrum. Particles may also accumulate on surfaces such as radiators, and degrade their performance. A computational model is developed to observe the behavior of particulate contamination in the spacecraft environment. This model self-consistently monitors the forces and charge on the particle.

  20. Nonproliferation, arms control and disarmament and extended deterrence in the new security environment

    Energy Technology Data Exchange (ETDEWEB)

    Pilat, Joseph F [Los Alamos National Laboratory

    2009-01-01

    With the end of the Cold War, in a dramatically changed security environment, the advances in nonnuclear strategic capabilities along with reduced numbers and roles for nuclear forces has altered the calculus of deterrence and defense, at least for the United States. For many, this opened up a realistic possibility of a nuclear-free world. It soon became clear that the initial post-Cold War hopes were exaggerated. The world did change fundamentally, but it did not become more secure and stable. In place of the old Soviet threat, there has been growing concern about proliferation and terrorism involving nuclear and other weapons of mass destruction (WMD), regional conflicts, global instability and increasingly serious new and emerging threats, including cyber attacks and attacks on satellites. For the United States at least, in this emerging environment, the political rationales for nuclear weapons, from deterrence to reassurance to alliance management, are changing and less central than during the Cold War to the security of the United States, its friends and allies. Nuclear weapons remain important for the US, but for a far more limited set of roles and missions. As the Perry-Schlesinger Commission report reveals, there is a domestic US consensus on nuclear policy and posture at the highest level and for the near term, including the continued role of nuclear arms in deterring WMD use and in reassuring allies. Although the value of nuclear weapons has declined for the United States, the value of these weapons for Russia, China and so-called 'rogue' states is seen to be rising. The nuclear logic of NATO during Cold War - the need for nuclear weapons to counter vastly superior conventional capabilities of the Soviet Union and the Warsaw Pact - is today heard from Russians and even some proliferants. Moreover, these weapons present a way for rogues to achieve regional hegemony and possibly to deter interventions by the United States or others. While the

  1. HARDWARE ENVIRONMENT FACTOR FOR CONTROL SIGNAL TRANSFER TO A PLANT IN THE SYNTHESIS PROBLEM OF DISCRETE SYSTEMS

    Directory of Open Access Journals (Sweden)

    O. S. Nuyya

    2015-07-01

    Full Text Available The paper attempts to revise certain provisions of the existing theory of discrete systems in the organization of hardware environment control signal transmission to a technical plant. It is known that the formation of a digital signal in discrete control problem of continuous plant is carried out by microcontroller or micro-computer and is represented by a parallel code, which dimension is determined by the hardware used. The parallel code for a digital clock cycle of the designed system is transmitted to the terminal device of a technical continuous plant, where the digital-to-analog conversion takes place. This kind of control signal transmission to the technical plant asserts its implementation by means of parallel buses. It is known that the length of a parallel bus is limited to an amount not exceeding half a meter due to the existing interference environment with modern standards of length. Thus, if the placement of the control signal and control plant is such that their connecting bus length exceeds more than half a meter, there is the inevitable transition from the parallel control signal to an allotted serial. The paper deals with the system factors arising in the transition from the parallel control signal to the serial by modern interfaces. Provisions of the paper are illustrated by an example. This paper is intended for system analytics and channel specialists. The resulting algorithm is applicable for control of plants (electric drive, in particular in the large industrial factories.

  2. Flexible sample environment for high resolution neutron imaging at high temperatures in controlled atmosphere

    DEFF Research Database (Denmark)

    Makowska, Malgorzata G.; Kuhn, Luise Theil; Cleemann, Lars Nilausen

    2015-01-01

    High material penetration by neutrons allows for experiments using sophisticated sample environments providing complex conditions. Thus, neutron imaging holds potential for performing in situ nondestructive measurements on large samples or even full technological systems, which are not possible w...

  3. Testing gene-environment interaction in large-scale case-control association studies: possible choices and comparisons.

    Science.gov (United States)

    Mukherjee, Bhramar; Ahn, Jaeil; Gruber, Stephen B; Chatterjee, Nilanjan

    2012-02-01

    Several methods for screening gene-environment interaction have recently been proposed that address the issue of using gene-environment independence in a data-adaptive way. In this report, the authors present a comparative simulation study of power and type I error properties of 3 classes of procedures: 1) the standard 1-step case-control method; 2) the case-only method that requires an assumption of gene-environment independence for the underlying population; and 3) a variety of hybrid methods, including empirical-Bayes, 2-step, and model averaging, that aim at gaining power by exploiting the assumption of gene-environment independence and yet can protect against false positives when the independence assumption is violated. These studies suggest that, although the case-only method generally has maximum power, it has the potential to create substantial false positives in large-scale studies even when a small fraction of markers are associated with the exposure under study in the underlying population. All the hybrid methods perform well in protecting against such false positives and yet can retain substantial power advantages over standard case-control tests. The authors conclude that, for future genome-wide scans for gene-environment interactions, major power gain is possible by using alternatives to standard case-control analysis. Whether a case-only type scan or one of the hybrid methods should be used depends on the strength and direction of gene-environment interaction and association, the level of tolerance for false positives, and the nature of replication strategies.

  4. Control of spontaneous emission of a single quantum emitter through a time-modulated photonic-band-gap environment

    Science.gov (United States)

    Calajò, Giuseppe; Rizzuto, Lucia; Passante, Roberto

    2017-08-01

    We consider the spontaneous emission of a two-level quantum emitter, such as an atom or a quantum dot, in a modulated time-dependent environment with a photonic band gap. An example of such an environment is a dynamical photonic crystal or any other environment with a band gap whose properties are modulated in time, in the effective mass approximation. After introducing our model of a dynamical photonic crystal, we show that it allows new possibilities to control and tailor the physical features of the emitted radiation, specifically its frequency spectrum. In the weak-coupling limit and in an adiabatic case, we obtain the emitted spectrum and we show the appearance of two lateral peaks due to the presence of the modulated environment, separated from the central peak by the modulation frequency. We show that the two side peaks are not symmetric in height, and that their height ratio can be exploited to investigate the density of states of the environment. Our results show that a dynamical environment can give further possibilities to modify the spontaneous emission features, such as its spectrum and emission rate, with respect to a static one. Observability of the phenomena we obtain is discussed, as well as relevance for tailoring and engineering radiative processes.

  5. Plant-centered biosystems in space environments: technological concepts for developing a plant genetic assessment and control system.

    Science.gov (United States)

    Lomax, Terri L; Findlay, Kirk A; White, T J; Winner, William E

    2003-06-01

    Plants will play an essential role in providing life support for any long-term space exploration or habitation. We are evaluating the feasibility of an adaptable system for measuring the response of plants to any unique space condition and optimizing plant performance under those conditions. The proposed system is based on a unique combination of systems including the rapid advances in the field of plant genomics, microarray technology for measuring gene expression, bioinformatics, gene pathways and networks, physiological measurements in controlled environments, and advances in automation and robotics. The resulting flexible module for monitoring and optimizing plant responses will be able to be inserted as a cassette into a variety of platforms and missions for either experimental or life support purposes. The results from future plant functional genomics projects have great potential to be applied to those plant species most likely to be used in space environments. Eventually, it will be possible to use the plant genetic assessment and control system to optimize the performance of any plant in any space environment. In addition to allowing the effective control of environmental parameters for enhanced plant productivity and other life support functions, the proposed module will also allow the selection or engineering of plants to thrive in specific space environments. The proposed project will advance human exploration of space in the near- and mid-term future on the International Space Station and free-flying satellites and in the far-term for longer duration missions and eventual space habitation.

  6. Bubble Induced Disruption of a Planar Solid-Liquid Interface During Controlled Directional Solidification in a Microgravity Environment

    Science.gov (United States)

    Grugel, Richard N.; Brush, Lucien N.; Anilkumar, Amrutur V.

    2013-01-01

    Pore Formation and Mobility Investigation (PFMI) experiments were conducted in the microgravity environment aboard the International Space Station with the intent of better understanding the role entrained porosity/bubbles play during controlled directional solidification. The planar interface in a slowing growing succinonitrile - 0.24 wt% water alloy was being observed when a nitrogen bubble traversed the mushy zone and remained at the solid-liquid interface. Breakdown of the interface to shallow cells subsequently occurred, and was later evaluated using down-linked data from a nearby thermocouple. These results and other detrimental effects due to the presence of bubbles during solidification processing in a microgravity environment are presented and discussed.

  7. A real-time human-perception interface for task-level control of a robot in unfamiliar environments

    Science.gov (United States)

    Miles, Eric Scott

    Recent advances in the development of semi-autonomous robotic systems offer numerous potential advantages in many engineering and science endeavors. Significant reductions in cost, time and risk, as well as increased capability, can be obtained by utilizing intelligent machines to assist humans. However, the use of robots also introduces many challenging issues, including the need for high-bandwidth stable control despite communication delays and operator fatigue. In response to these challenges, the Stanford Aerospace Robotics Laboratory has pioneered the Task-Level Control architecture, which enables humans to direct, from a strategic level, sophisticated tasks that a robot then executes autonomously. The research reported here is intended to extend the Task-Level Control architecture significantly--by using human perception in a natural way--to work well in unfamiliar environments. An unfamiliar environment is defined to be one about which it is impossible to have perfect and complete knowledge before developing and deploying a robotic system. Clearly, every work environment is, to some extent, unfamiliar. This research has shown that drawing intimately, in real time, upon a human's deep visual perception is extremely effective in overcoming such unfamiliarity. A novel interactive vision-based operator interface for directing a highly autonomous robot operating in an unfamiliar environment is presented. Intuitive interaction with a live-video display from cameras on board the robot is used in combination with stereo-vision algorithms to maintain the operator's attention at the overall object-level during the modeling process. With this interface, the human's remarkable ability to discern entire object-level constructs is utilized to produce quick, cogent and robust models of unexpected and unknown objects in the environment. Once unfamiliar objects have been suitably modeled, tasks involving those objects can be directed via the Task-Level Control architecture

  8. Implementation and Validation of EtherCAT Support in Integrated Development Environment for Synchronized Motion Control Application

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jongbo; Kim, Chaerin; Kim, Ikhwan; Kim, Youngdong; Kim, Taehyoun [Univ. of Seoul, Seoul (Korea, Republic of)

    2014-02-15

    Recently, software-based programmable logic controller (PLC) systems, which are implemented in standard PLC languages on general hardware, are gaining popularity because they overcome the limitations of classical hardware PLC systems. Another noticeable trend is that the use of integrated development environment (IDE) is becoming important. IDEs can help developers to easily manage the growing complexity of modern control systems. Furthermore, industrial Ethernet, e. g. EtherCAT, is becoming widely accepted as a replacement for conventional fieldbuses in the distributed control domain because it offers favorable features such as short transmission delay, high bandwidth, and low cost. In this paper, we implemented the extension of open source IDE, called Beremiz, for developing EtherCAT-based real-time, synchronized motion control applications. We validated the EtherCAT system management features and the real-time responsiveness of the control function by using commercial EtherCAT drives and evaluation boards.

  9. Diabetes Learning in Virtual Environments: Testing the Efficacy of Self-Management Training and Support in Virtual Environments (Randomized Controlled Trial Protocol).

    Science.gov (United States)

    Vorderstrasse, Allison A; Melkus, Gail D; Pan, Wei; Lewinski, Allison A; Johnson, Constance M

    2015-01-01

    Ongoing self-management improves outcomes for those with Type 2 diabetes (T2D); however, there are many barriers to patients receiving assistance in this from the healthcare system and peers. Findings from our pilot study showed that a virtual diabetes community on the Internet with real-time interaction among peers with T2D-and with healthcare professionals-is feasible and has the potential to influence clinical and psychosocial outcomes. The purpose of this article is to present the protocol for the Diabetes Learning in Virtual Environments (LIVE) trial. Diabetes LIVE is a two-group, randomized controlled trial to compare effects of a virtual environment and traditional Web site on diet and physical activity. Our secondary aims will determine the effects on metabolic outcomes; effects of level of engagement and social network formation in LIVE on behavioral outcomes; potential mediating effects of changes in self-efficacy; and diabetes knowledge, diabetes-related distress, and social support on behavior change and metabolic outcomes. We will enroll 300 subjects at two sites (Duke University/Raleigh-Durham, NC and New York University/New York, NY) who have T2D and do not have serious complications or comorbidities. Those randomly assigned to the intervention group have access to the LIVE site where they can find information, synchronous classes with diabetes educators, and peer support to enhance self-management. Those in the control group have access to the same informational and educational content in a traditional asynchronous Web format. Measures of self-management, clinical outcomes, and psychosocial outcomes are assessed at baseline and 3, 6, 12, and 18 months. Should LIVE prove effective in improved self-management of diabetes, similar interventions could be applied to other prevalent chronic diseases. Innovative programs such as LIVE have potential for improving healthcare access in an easily disseminated alternative model of care that potentially improves

  10. An estimation method of the direct benefit of a waterlogging control project applicable to the changing environment

    Science.gov (United States)

    Zengmei, L.; Guanghua, Q.; Zishen, C.

    2015-05-01

    The direct benefit of a waterlogging control project is reflected by the reduction or avoidance of waterlogging loss. Before and after the construction of a waterlogging control project, the disaster-inducing environment in the waterlogging-prone zone is generally different. In addition, the category, quantity and spatial distribution of the disaster-bearing bodies are also changed more or less. Therefore, under the changing environment, the direct benefit of a waterlogging control project should be the reduction of waterlogging losses compared to conditions with no control project. Moreover, the waterlogging losses with or without the project should be the mathematical expectations of the waterlogging losses when rainstorms of all frequencies meet various water levels in the drainage-accepting zone. So an estimation model of the direct benefit of waterlogging control is proposed. Firstly, on the basis of a Copula function, the joint distribution of the rainstorms and the water levels are established, so as to obtain their joint probability density function. Secondly, according to the two-dimensional joint probability density distribution, the dimensional domain of integration is determined, which is then divided into small domains so as to calculate the probability for each of the small domains and the difference between the average waterlogging loss with and without a waterlogging control project, called the regional benefit of waterlogging control project, under the condition that rainstorms in the waterlogging-prone zone meet the water level in the drainage-accepting zone. Finally, it calculates the weighted mean of the project benefit of all small domains, with probability as the weight, and gets the benefit of the waterlogging control project. Taking the estimation of benefit of a waterlogging control project in Yangshan County, Guangdong Province, as an example, the paper briefly explains the procedures in waterlogging control project benefit estimation. The

  11. Control an Electromechanical System in the Real-Time Linux Environment

    Directory of Open Access Journals (Sweden)

    Matej Dobšovič

    2008-05-01

    Full Text Available This article is concerned with possibilities of control in real-time using Real-Time Linux (RTL. It describes the control abilities of a Personal Computer (PC with RTLoperating system, cooperation with industrial control cards, the architecture of controlsoftware and possibilities of use in real applications. We are putting forward experiencewith a simple interconnection between the RTL kernel and a control card using the Comedisoftware package.

  12. Kinematics modeling and control simulation for a logging harvester in virtual environments

    OpenAIRE

    2015-01-01

    This article presents the kinematics model and control simulation of a hydraulic boom. This hydraulic boom is used on the logging harvester, which is a typical forestry vehicle. The kinematics equations of the hydraulic boom and the transformation between joint variables and hydraulic cylinder variables are obtained for the control purpose. An autonomous control method is suggested for the harvesting head to capture trunks. There are two separate closed loops in the control scheme: the inner ...

  13. Landmark-based robust navigation for tactical UGV control in GPS-denied communication-degraded environments

    Science.gov (United States)

    Endo, Yoichiro; Balloch, Jonathan C.; Grushin, Alexander; Lee, Mun Wai; Handelman, David

    2016-05-01

    Control of current tactical unmanned ground vehicles (UGVs) is typically accomplished through two alternative modes of operation, namely, low-level manual control using joysticks and high-level planning-based autonomous control. Each mode has its own merits as well as inherent mission-critical disadvantages. Low-level joystick control is vulnerable to communication delay and degradation, and high-level navigation often depends on uninterrupted GPS signals and/or energy-emissive (non-stealth) range sensors such as LIDAR for localization and mapping. To address these problems, we have developed a mid-level control technique where the operator semi-autonomously drives the robot relative to visible landmarks that are commonly recognizable by both humans and machines such as closed contours and structured lines. Our novel solution relies solely on optical and non-optical passive sensors and can be operated under GPS-denied, communication-degraded environments. To control the robot using these landmarks, we developed an interactive graphical user interface (GUI) that allows the operator to select landmarks in the robot's view and direct the robot relative to one or more of the landmarks. The integrated UGV control system was evaluated based on its ability to robustly navigate through indoor environments. The system was successfully field tested with QinetiQ North America's TALON UGV and Tactical Robot Controller (TRC), a ruggedized operator control unit (OCU). We found that the proposed system is indeed robust against communication delay and degradation, and provides the operator with steady and reliable control of the UGV in realistic tactical scenarios.

  14. Multi-parameter decoupling and slope tracking control strategy of a large-scale high altitude environment simulation test cabin

    Institute of Scientific and Technical Information of China (English)

    Li Ke; Liu Wangkai; Wang Jun; Huang Yong; Liu Meng

    2014-01-01

    A large-scale high altitude environment simulation test cabin was developed to accu-rately control temperatures and pressures encountered at high altitudes. The system was developed to provide slope-tracking dynamic control of the temperature–pressure two-parameter and over-come the control difficulties inherent to a large inertia lag link with a complex control system which is composed of turbine refrigeration device, vacuum device and liquid nitrogen cooling device. The system includes multi-parameter decoupling of the cabin itself to avoid equipment damage of air refrigeration turbine caused by improper operation. Based on analysis of the dynamic characteris-tics and modeling for variations in temperature, pressure and rotation speed, an intelligent control-ler was implemented that includes decoupling and fuzzy arithmetic combined with an expert PID controller to control test parameters by decoupling and slope tracking control strategy. The control system employed centralized management in an open industrial ethernet architecture with an indus-trial computer at the core. The simulation and field debugging and running results show that this method can solve the problems of a poor anti-interference performance typical for a conventional PID and overshooting that can readily damage equipment. The steady-state characteristics meet the system requirements.

  15. A lean production control system for high-variety/low-volume environments : a case study implementation

    NARCIS (Netherlands)

    Slomp, J.; Bokhorst, J.A.C.; Germs, R.

    2009-01-01

    Due to the success of lean manufacturing, many companies are interested in implementing a lean production control system. Lean production control principles include the levelling of production, the use of pull mechanisms and takt time control. These principles have mainly been applied in high volume

  16. A Comparative Study of Memory-Type Control Charts under Normal and Contaminated Normal Environments

    NARCIS (Netherlands)

    Nazir, H.Z.; Abbas, N.; Riaz, M.; Does, R.J.M.M.

    2016-01-01

    Cumulative sum (CUSUM) and exponentially weighted moving average (EWMA) control charts are commonly used to detect small changes in the parameters of production processes. Recently, a new control structure was introduced, named as mixed EWMA–CUSUM control chart, which combined both charts. The

  17. A Comparative Study of Memory-Type Control Charts under Normal and Contaminated Normal Environments

    NARCIS (Netherlands)

    Nazir, H.Z.; Abbas, N.; Riaz, M.; Does, R.J.M.M.

    2016-01-01

    Cumulative sum (CUSUM) and exponentially weighted moving average (EWMA) control charts are commonly used to detect small changes in the parameters of production processes. Recently, a new control structure was introduced, named as mixed EWMA–CUSUM control chart, which combined both charts. The curre

  18. A lean production control system for high-variety/low-volume environments : a case study implementation

    NARCIS (Netherlands)

    Slomp, J.; Bokhorst, J.A.C.; Germs, R.

    2009-01-01

    Due to the success of lean manufacturing, many companies are interested in implementing a lean production control system. Lean production control principles include the levelling of production, the use of pull mechanisms and takt time control. These principles have mainly been applied in high volume

  19. Calcium localization in lettuce leaves with and without tipburn: comparison of controlled-environment and field-grown plants

    Science.gov (United States)

    Barta, D. J.; Tibbitts, T. W.

    1991-01-01

    An electron microprobe was used to determine tissue concentrations of Ca across 20-mm-long leaves of 'Green Lakes' crisphead lettuce (Lactuca sativa L.) with and without tipburn injury. Concentrations within the fifth and 14th leaves, counted from the cotyledons, from plants grown under controlled-environment conditions were compared to concentrations within similar leaves obtained from plants grown under field conditions. Only the 14th leaf from plants grown under controlled-environment conditions developed tipburn. Injured areas on these leaves had Ca concentrations as low as 0.2 to 0.3 mg g-1 dry weight. Uninjured areas of tipburned leaves contained from 0.4 to 0.5 mg g-1 dry weight. Concentrations across the uninjured 14th leaf from field-grown plants averaged 1.0 mg g-1 dry weight. Amounts across the uninjured fifth leaves from both environments averaged 1.6 mg g-1 dry weight. In contrast, Mg concentrations were higher in injured leaves than in uninjured leaves and thus were negatively correlated with Ca concentrations. Magnesium concentrations averaged 4.7 mg g-1 dry weight in injured leaves compared with 3.4 mg g-1 dry weight in uninjured leaves from both environments. Magnesium concentrations were uniform across the leaf. Potassium concentrations were highest at the leaf apex and decreased toward the base and also decreased from the midrib to the margin. Potassium averaged 51 mg g-1 dry weight in injured and uninjured leaves from both environments. No significant differences in K concentration were present between injured and uninjured leaves. This study documented that deficient concentrations of Ca were present in areas of leaf tissue developing tipburn symptoms and that concentrations were significantly higher in similar areas of other leaves that had no symptoms. This study also documented that Ca concentrations were significantly lower in enclosed leaves that exhibited tipburn symptoms than in exposed leaves that did not exhibit tipburn. Also, the

  20. Nonproliferation, arms control and disarmament and extended deterrence in the new security environment

    Energy Technology Data Exchange (ETDEWEB)

    Pilat, Joseph F [Los Alamos National Laboratory

    2009-01-01

    With the end of the Cold War, in a dramatically changed security environment, the advances in nonnuclear strategic capabilities along with reduced numbers and roles for nuclear forces has altered the calculus of deterrence and defense, at least for the United States. For many, this opened up a realistic possibility of a nuclear-free world. It soon became clear that the initial post-Cold War hopes were exaggerated. The world did change fundamentally, but it did not become more secure and stable. In place of the old Soviet threat, there has been growing concern about proliferation and terrorism involving nuclear and other weapons of mass destruction (WMD), regional conflicts, global instability and increasingly serious new and emerging threats, including cyber attacks and attacks on satellites. For the United States at least, in this emerging environment, the political rationales for nuclear weapons, from deterrence to reassurance to alliance management, are changing and less central than during the Cold War to the security of the United States, its friends and allies. Nuclear weapons remain important for the US, but for a far more limited set of roles and missions. As the Perry-Schlesinger Commission report reveals, there is a domestic US consensus on nuclear policy and posture at the highest level and for the near term, including the continued role of nuclear arms in deterring WMD use and in reassuring allies. Although the value of nuclear weapons has declined for the United States, the value of these weapons for Russia, China and so-called 'rogue' states is seen to be rising. The nuclear logic of NATO during Cold War - the need for nuclear weapons to counter vastly superior conventional capabilities of the Soviet Union and the Warsaw Pact - is today heard from Russians and even some proliferants. Moreover, these weapons present a way for rogues to achieve regional hegemony and possibly to deter interventions by the United States or others. While the

  1. Who's in Control? Teachers from Five Countries Share Perspectives on Power Dynamics in the Learning Environment

    Science.gov (United States)

    Lovorn, Michael; Sunal, Cynthia Szymanski; Christensen, Lois McFadyen; Sunal, Dennis W.; Shwery, Craig

    2012-01-01

    This article explores perspectives and strands of thought among teachers from five countries about power dynamics in learning environments, perspectives on power of dominant cultures and impacts of power on concepts of citizenship and social justice. Discourses revealed teachers have some understanding of how power impacts teaching and learning,…

  2. Runoff controlling factors in various sized catchments in a semi-arid Mediterranean environment in Spain

    NARCIS (Netherlands)

    Wit, A.M.W. de

    2001-01-01

    Understanding land degradation in a semi-arid Mediterranean environment is very difficult because of the contributing factors: precipitation, infiltration vegetation cover and discontinuity of flow and the temporal and spatial levels of resolution at which these factors are acting. Therefore it is s

  3. The Networked Student Model for Construction of Personal Learning Environments: Balancing Teacher Control and Student Autonomy

    Science.gov (United States)

    Drexler, Wendy

    2010-01-01

    Principles of networked learning, constructivism, and connectivism inform the design of a test case through which secondary students construct personal learning environments for the purpose of independent inquiry. Emerging web applications and open educational resources are integrated to support a "Networked Student Model" that promotes…

  4. The South African legislative environment, in critical need of scientific evidence based alignment for airborne control

    CSIR Research Space (South Africa)

    Fleming, EJ

    2014-07-01

    Full Text Available Review of evidence based research indicates that there are best practice principles that can be applied to the design of the built environment with regard to the reduction of the risk of cross infection from airborne diseases in health facilities...

  5. The Networked Student Model for Construction of Personal Learning Environments: Balancing Teacher Control and Student Autonomy

    Science.gov (United States)

    Drexler, Wendy

    2010-01-01

    Principles of networked learning, constructivism, and connectivism inform the design of a test case through which secondary students construct personal learning environments for the purpose of independent inquiry. Emerging web applications and open educational resources are integrated to support a "Networked Student Model" that promotes…

  6. Control of an Autonomous Radio-Controlled Helicopter in a Modified Simulation Environment Using Proportional Integral Derivative Algorithms

    Science.gov (United States)

    2008-06-01

    outputs, even when tracking a single position, maintaining hover without GPS can be considered useful under short-term conditions. All PID controllers also...user can deduce that his or her initial hunch was wrong and look elsewhere for a solution. 4. Key Flight Modes 4.1 Trim State Although PID ... controllers will eventually settle into a final value after receiving stable gains, there may still be errors present even with a strong Ki term. As such

  7. Nonlinear Adaptive PID Control for Greenhouse Environment Based on RBF Network

    Directory of Open Access Journals (Sweden)

    Guanghui Li

    2012-04-01

    Full Text Available This paper presents a hybrid control strategy, combining Radial Basis Function (RBF network with conventional proportional, integral, and derivative (PID controllers, for the greenhouse climate control. A model of nonlinear conservation laws of enthalpy and matter between numerous system variables affecting the greenhouse climate is formulated. RBF network is used to tune and identify all PID gain parameters online and adaptively. The presented Neuro-PID control scheme is validated through simulations of set-point tracking and disturbance rejection. We compare the proposed adaptive online tuning method with the offline tuning scheme that employs Genetic Algorithm (GA to search the optimal gain parameters. The results show that the proposed strategy has good adaptability, strong robustness and real-time performance while achieving satisfactory control performance for the complex and nonlinear greenhouse climate control system, and it may provide a valuable reference to formulate environmental control strategies for actual application in greenhouse production.

  8. Nonlinear adaptive PID control for greenhouse environment based on RBF network.

    Science.gov (United States)

    Zeng, Songwei; Hu, Haigen; Xu, Lihong; Li, Guanghui

    2012-01-01

    This paper presents a hybrid control strategy, combining Radial Basis Function (RBF) network with conventional proportional, integral, and derivative (PID) controllers, for the greenhouse climate control. A model of nonlinear conservation laws of enthalpy and matter between numerous system variables affecting the greenhouse climate is formulated. RBF network is used to tune and identify all PID gain parameters online and adaptively. The presented Neuro-PID control scheme is validated through simulations of set-point tracking and disturbance rejection. We compare the proposed adaptive online tuning method with the offline tuning scheme that employs Genetic Algorithm (GA) to search the optimal gain parameters. The results show that the proposed strategy has good adaptability, strong robustness and real-time performance while achieving satisfactory control performance for the complex and nonlinear greenhouse climate control system, and it may provide a valuable reference to formulate environmental control strategies for actual application in greenhouse production.

  9. A Fuzzy Logic Behavior Architecture Controller for a Mobile Robot Path Planning in Multi-obstacles Environment

    Directory of Open Access Journals (Sweden)

    Zhu Qi-dan

    2013-04-01

    Full Text Available The path planning and obstacle avoidance are the most important tasks for an autonomous mobile robot moving in an unknown environment. This paper presents a simple fuzzy logic controller which involves searching target and path planning with obstacle avoidance. In this contest, fuzzy logic controllers are constructed for target searching behavior and obstacle avoidance behavior based on the distance and angle between the robot and the target as inputs for the first behavior and the distance between the robot and the nearest obstacle for the second behavior; then a third fusion behavior is developed to combine the outputs of the two behaviors to compute the speed of the mobile robot in order to fulfill its task properly. Simulation results show that the proposed approach is efficient and can be applied to the mobile robots moving in unknown environments.

  10. Environment control to improve recombinant protein yields in plants based on Agrobacterium-mediated transient gene expression

    Directory of Open Access Journals (Sweden)

    Naomichi eFujiuchi

    2016-03-01

    Full Text Available Agrobacterium-mediated transient expression systems enable plants to produce a wide range of recombinant proteins on a rapid timescale. To achieve economically feasible upstream production and downstream processing, two yield parameters should be considered: 1 recombinant protein content per unit biomass; and 2 recombinant protein productivity per unit area-time at the end of the upstream production. Because environmental factors in the upstream production have impacts on those parameters, environment control is important to maximize the recombinant protein yield. In this review, we summarize the effects of pre- and post-inoculation environmental factors in the upstream production on the yield parameters and discuss the basic concept of environment control for plant-based transient expression systems. Pre-inoculation environmental factors associated with planting density, light quality and nutrient supply affect plant characteristics such as biomass and morphology, which in turn affect recombinant protein content and productivity. Accordingly, environment control for such plant characteristics has significant implications to achieve a high yield. On the other hand, post-inoculation environmental factors such as temperature, light intensity and humidity have been shown to affect recombinant protein content. Considering that recombinant protein production in Agrobacterium-mediated transient expression systems is a result of a series of complex biological events starting from T-DNA transfer from Agrobacterium tumefaciens to protein biosynthesis and accumulation in leaf tissue, we propose that dynamic environment control during the post-inoculation process, i.e., changing environmental conditions at an appropriate timing for each event, may be a promising approach to obtain a high yield. Detailed descriptions of plant growth conditions and careful examination of environmental effects will significantly contribute to our knowledge to stably obtain

  11. Heading assessment by “tunnel vision” patients and control subjects standing or walking in a virtual reality environment

    OpenAIRE

    Apfelbaum, Henry; Pelah, Adar; Peli, Eli

    2007-01-01

    Virtual reality locomotion simulators are a promising tool for evaluating the effectiveness of vision aids to mobility for people with low vision. This study examined two factors to gain insight into the verisimilitude requirements of the test environment: the effects of treadmill walking and the suitability of using controls as surrogate patients. Ten “tunnel vision” patients with retinitis pigmentosa (RP) were tasked with identifying which side of a clearly visible obstacle their heading th...

  12. An investigation into the effectiveness of statistical process control techniques, with management data from a product development environment

    OpenAIRE

    Julien, Denyse

    1998-01-01

    The study reported on in this thesis was an empirical investigation into the implementation and use of, Statistical Process Control (SPC) techniques and tools in a product development environment. The data used originated from four different business units in the European flavour division of a large International company, belonging to the Flavour and Fragrance industry. The study highlights many of the problems related to the use of real data, and working with individuals throughout an organi...

  13. Event-triggered H∞ reliable control for offshore structures in network environments

    Science.gov (United States)

    Zhang, Bao-Lin; Han, Qing-Long; Zhang, Xian-Ming

    2016-04-01

    This paper investigates the network-based modeling and event-triggered H∞ reliable control for an offshore structure. First, a network-based model of the offshore structure subject to external wave force and actuator faults is presented. Second, an event-triggering mechanism is proposed such that during the control implementation, only requisite sampled-data is transmitted over networks. Third, an event-triggered H∞ reliable control problem for the offshore structure is solved by employing the Lyapunov-Krasovskii functional approach, and the desired controller can be derived. It is shown through simulation results that for possible actuator failures, the networked controller is capable of guaranteeing the stability of the offshore structure. In addition, compared with the H∞ control scheme without network settings, the proposed controller can suppress the vibration of the offshore structure to almost the same level as the H∞ controller, while the former requires less control cost. Furthermore, under the network-based controller, the communication resources can be saved significantly.

  14. The ambiguity of contents and results in the Norwegian internal control of safety, health and environment reform

    Energy Technology Data Exchange (ETDEWEB)

    Hovden, Jan

    1998-05-01

    The results of introducing a mandatory public reform in Norway with regard to the requirements on enterprises' management of safety, health and environment (SHE) systems are reviewed and discussed. The reform, named internal control (IC), implies a delegation of the direct control of SHE conditions to the enterprises, and introduces system auditing as the main tool for the regulatory bodies. A mixture of successes and failures in implementing the reform, including some perspectives for further adaptation and development of the IC concept are discussed.

  15. Kinematics modeling and control simulation for a logging harvester in virtual environments

    Directory of Open Access Journals (Sweden)

    Yili Zheng

    2015-10-01

    Full Text Available This article presents the kinematics model and control simulation of a hydraulic boom. This hydraulic boom is used on the logging harvester, which is a typical forestry vehicle. The kinematics equations of the hydraulic boom and the transformation between joint variables and hydraulic cylinder variables are obtained for the control purpose. An autonomous control method is suggested for the harvesting head to capture trunks. There are two separate closed loops in the control scheme: the inner closed loop realizes the control on the hydraulic cylinders, and the outer loop plans the desired trajectory of the harvesting head to capture trunks based on the laser measurement data. An interactive real-time dynamic simulation system is developed, and the proposed control method is verified.

  16. Model Predictive Control of a Continuous Vacuum Crystalliser in an Industrial Environment: A Feasibility Study

    OpenAIRE

    Moldoványi, N.; Abonyi, J.

    2009-01-01

    Crystallisers are essentially multivariable systems with high interaction amongst the process variables. Model Predictive Controllers (MPC) can handle such highly interacting multivariable systems efficiently due to their coordinated approach. In the absence of a real continuous crystalliser, a detailed momentum-model was applied using the process simulator in Simulink. This process has been controlled by a model predictive controller widely used in industry. A new framework has been worke...

  17. Heading assessment by "tunnel vision" patients and control subjects standing or walking in a virtual reality environment.

    Science.gov (United States)

    Apfelbaum, Henry; Pelah, Adar; Peli, Eli

    2007-01-01

    Virtual reality locomotion simulators are a promising tool for evaluating the effectiveness of vision aids to mobility for people with low vision. This study examined two factors to gain insight into the verisimilitude requirements of the test environment: the effects of treadmill walking and the suitability of using controls as surrogate patients. Ten "tunnel vision" patients with retinitis pigmentosa (RP) were tasked with identifying which side of a clearly visible obstacle their heading through the virtual environment would lead them, and were scored both on accuracy and on their distance from the obstacle when they responded. They were tested both while walking on a treadmill and while standing, as they viewed a scene representing progress through a shopping mall. Control subjects, each wearing a head-mounted field restriction to simulate the vision of a paired patient, were also tested. At wide angles of approach, controls and patients performed with a comparably high degree of accuracy, and made their choices at comparable distances from the obstacle. At narrow angles of approach, patients' accuracy increased when walking, while controls' accuracy decreased. When walking, both patients and controls delayed their decisions until closer to the obstacle. We conclude that a head-mounted field restriction is not sufficient for simulating tunnel vision, but that the improved performance observed for walking compared to standing suggests that a walking interface (such as a treadmill) may be essential for eliciting natural perceptually-guided behavior in virtual reality locomotion simulators.

  18. Fuzzy Theory Based Control Method for an In-pipe Robot to Move in Variable Resistance Environment

    Institute of Scientific and Technical Information of China (English)

    LI Te; MA Shugen; LI Bin; WANG Minghui; WANG Yuechao

    2015-01-01

    Most of the existing screw drive in-pipe robots cannot actively adjust the maximum traction capacity, which limits the adaptability to the wide range of variable environment resistance, especially in curved pipes. In order to solve this problem, a screw drive in-pipe robot based on adaptive linkage mechanism is proposed. The differential property of the adaptive linkage mechanism allows the robot to move without motion interference in the straight and varied curved pipes by adjusting inclining angles of rollers self-adaptively. The maximum traction capacity of the robot can be changed by actively adjusting the inclining angles of rollers. In order to improve the adaptability to the variable resistance, a torque control method based on the fuzzy controller is proposed. For the variable environment resistance, the proposed control method can not only ensure enough traction force, but also limit the output torque in a feasible region. In the simulations, the robot with the proposed control method is compared to the robot with fixed inclining angles of rollers. The results show that the combination of the torque control method and the proposed robot achieves the better adaptability to the variable resistance in the straight and curved pipes.

  19. SITUATION ASSESSMENT THROUGH MULTI-MODAL SENSING OF DYNAMIC ENVIRONMENTS TO SUPPORT COGNITIVE ROBOT CONTROL

    Directory of Open Access Journals (Sweden)

    Atta Badii

    2014-12-01

    Full Text Available Awareness of emerging situations in a dynamic operational environment of a robotic assistive device is an essential capability of such a cognitive system, based on its effective and efficient assessment of the prevailing situation. This allows the system to interact with the environment in a sensible (semiautonomous / pro-active manner without the need for frequent interventions from a supervisor.  In this paper, we report a novel generic Situation Assessment Architecture for robotic systems directly assisting humans as developed in the CORBYS project. This paper presents the overall architecture for situation assessment and its application in proof-of-concept Demonstrators as developed and validated within the CORBYS project. These include a robotic human follower and a mobile gait rehabilitation robotic system. We present an overview of the structure and functionality of the Situation Assessment Architecture for robotic systems with results and observations as collected from initial validation on the two CORBYS Demonstrators.

  20. Gene-Environment Interactions Controlling Energy and Glucose Homeostasis and the Developmental Origins of Obesity

    Science.gov (United States)

    Bouret, Sebastien; Levin, Barry E.; Ozanne, Susan E.

    2015-01-01

    Obesity and type 2 diabetes mellitus (T2DM) often occur together and affect a growing number of individuals in both the developed and developing worlds. Both are associated with a number of other serious illnesses that lead to increased rates of mortality. There is likely a polygenic mode of inheritance underlying both disorders, but it has become increasingly clear that the pre- and postnatal environments play critical roles in pushing predisposed individuals over the edge into a disease state. This review focuses on the many genetic and environmental variables that interact to cause predisposed individuals to become obese and diabetic. The brain and its interactions with the external and internal environment are a major focus given the prominent role these interactions play in the regulation of energy and glucose homeostasis in health and disease. PMID:25540138

  1. Diazepam Binding Inhibitor Promotes Stem Cell Expansion Controlling Environment-Dependent Neurogenesis.

    Science.gov (United States)

    Dumitru, Ionut; Neitz, Angela; Alfonso, Julieta; Monyer, Hannah

    2017-04-05

    Plasticity of adult neurogenesis supports adaptation to environmental changes. The identification of molecular mediators that signal these changes to neural progenitors in the niche has remained elusive. Here we report that diazepam binding inhibitor (DBI) is crucial in supporting an adaptive mechanism in response to changes in the environment. We provide evidence that DBI is expressed in stem cells in all neurogenic niches of the postnatal brain. Focusing on the hippocampal subgranular zone (SGZ) and employing multiple genetic manipulations in vivo, we demonstrate that DBI regulates the balance between preserving the stem cell pool and neurogenesis. Specifically, DBI dampens GABA activity in stem cells, thereby sustaining the proproliferative effect of physical exercise and enriched environment. Our data lend credence to the notion that the modulatory effect of DBI constitutes a general mechanism that regulates postnatal neurogenesis. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. A Study of Smart Power Control Algorithm Using RF Communication in Smart Home Environment

    OpenAIRE

    Su-hong Shin; Kyoung-hwa Do; Byoung-soo Koh

    2013-01-01

    Today’s technologies in the IT area face the era of combination and convergence of technologies in many different areas. Through the natural interaction between people and devices in the environment where various kinds of devices are connected over a single network, they have been developing from human-oriented service technologies to smart and futuristic home technologies. Smart home technology is one of them. It is a technology of establishing a digital home in which various kinds of home a...

  3. Modelling and Control of Stepper Motors for High Accuracy Positioning Systems Used in Radioactive Environments

    OpenAIRE

    Picatoste Ruilope, Ricardo

    2014-01-01

    Hybrid Stepper Motors are widely used in open-loop position applications. They are the choice of actuation for the collimators in the Large Hadron Collider, the largest particle accelerator at CERN. In this case the positioning requirements and the highly radioactive operating environment are unique. The latter forces both the use of long cables to connect the motors to the drives which act as transmission lines and also prevents the use of standard position sensors. However, reliable and pre...

  4. A case-control study on the occurrence of Salmonella spp. in the environment of pigs.

    Science.gov (United States)

    Gotter, V; Blaha, T; Klein, G

    2012-01-01

    The objective of this study was to compare the occurrence of Salmonella spp. found in the animal environment in pig herds with different Salmonella risks (61 herds with low seroprevalence, 81 herds with high seroprevalence) on a broad scale. The environmental samples were divided into two types: direct (n=1105) and indirect (n=1220) environmental samples. All samples were tested for Salmonella spp. via real-time polymerase chain reaction. Most of the indirect environments were more often Salmonella-positive in the high-seroprevalence herds than in the low-seroprevalence herds; significantly higher were compartment aisles [odds ratio (OR) 3·45, 95% confidence interval (CI) 1·61-7·41], driving boards (OR 3·06, 95% CI 1·38-6·92) and the central aisle of the barn (OR 3·03, 95% CI 1·35-6·83). The overall results show that especially areas in the indirect environment are the major, but mostly underestimated causes of residual Salmonella.

  5. Using noise to control heterogeneity of isogenic populations in homogenous environments

    Science.gov (United States)

    Szymańska, Paulina; Gritti, Nicola; Keegstra, Johannes M.; Soltani, Mohammad; Munsky, Brian

    2015-07-01

    We explore the extent to which the phenotypes of individual, genetically identical cells can be controlled independently from each other using only a single homogeneous environmental input. We show that such control is theoretically impossible if restricted to a deterministic setting, but it can be achieved readily if one exploits heterogeneities introduced at the single-cell level due to stochastic fluctuations in gene regulation. Using stochastic analyses of a bistable genetic toggle switch, we develop a control strategy that maximizes the chances that a chosen cell will express one phenotype, while the rest express another. The control mechanism uses UV radiation to enhance identically protein degradation in all cells. Control of individual cells is made possible only by monitoring stochastic protein fluctuations and applying UV control at favorable times and levels. For two identical cells, our stochastic control law can drive protein expression of a chosen cell above its neighbor with a better than 99% success rate. In a population of 30 identical cells, we can drive a given cell to remain consistently within the top 20%. Although cellular noise typically impairs predictability for biological responses, our results show that it can also simultaneously improve controllability for those same responses.

  6. A Nonlinear Model Predictive Control Algorithm for Obstacle Avoidance in Autonomous Ground Vehicles within Unknown Environments

    Science.gov (United States)

    2015-04-24

    Allgwer and A. Zheng, Nonlinear model predictive control vol. 26: Springer , 2000. [10] J. M. Park, D. W. Kim, Y. S. Yoon, H. J. Kim, and K. S. Yi...include modeling, simulation, and control of dynamic systems, with applications to energy systems, multibody dynamics, vehicle systems, and biomechanics

  7. Controlling a stream of paranoia evoking events in a virtual reality environment

    NARCIS (Netherlands)

    Isnanda, Reza Giga; Brinkman, Willem-Paul; Veling, Wim; van der Gaag, Mark; Neerincx, Mark

    2014-01-01

    Although virtual reality exposure has been reported as a method to induce paranoid thought, little is known about mechanisms to control specific virtual stressors. This paper reports on a study that examines the effect of controlling the stream of potential paranoia evoking events in a virtual resta

  8. Controlling a stream of paranoia evoking events in a virtual reality environment

    NARCIS (Netherlands)

    Isnanda, Reza Giga; Brinkman, Willem-Paul; Veling, Wim; van der Gaag, Mark; Neerincx, Mark

    2014-01-01

    Although virtual reality exposure has been reported as a method to induce paranoid thought, little is known about mechanisms to control specific virtual stressors. This paper reports on a study that examines the effect of controlling the stream of potential paranoia evoking events in a virtual

  9. AGC of a multi-area power system under deregulated environment using redox flow batteries and interline power flow controller

    Directory of Open Access Journals (Sweden)

    Tulasichandra Sekhar Gorripotu

    2015-12-01

    Full Text Available In this paper, Proportional Integral Derivative with Filter (PIDF is proposed for Automatic Generation Control (AGC of a multi-area power system in deregulated environment. Initially, a two area four units thermal system without any physical constraints is considered and the gains of the PIDF controller are optimized employing Differential Evolution (DE algorithm using ITAE criterion. The superiority of proposed DE optimized PIDF controller over Fuzzy Logic controller is demonstrated. Then, to further improve the system performance, an Interline Power Flow Controller (IPFC is placed in the tie-line and Redox Flow Batteries (RFB is considered in the first area and the controller parameters are tuned. Additionally, to get an accurate insight of the AGC problem, important physical constraints such as Time Delay (TD and Generation Rate Constraints (GRC are considered and the controller parameters are retuned. The performance of proposed controller is evaluated under different operating conditions that take place in a deregulated power market. Further, the proposed approach is extended to a two area six units hydro thermal system. Finally, sensitivity analysis is performed by varying the system parameters and operating load conditions from their nominal values.

  10. CALCULATION OF CONTROL CIRCUITS IN TIME DOMAIN USING SCILAB / XCOS ENVIRONMENT

    Directory of Open Access Journals (Sweden)

    Chioncel Petru

    2014-10-01

    Full Text Available The paper presents the computing of control circuits in time domain, starting from the mathematical model of the control path described by differential equation’s with constant coefficients, whose solution can be obtained through Laplace transform and transfer functions. In the field of electric drives, the control circuits can be reduced to elements of PT1 and PT2 type, for which, the responses obtained from step and impulse function in the test process, are analyzed. The presented calculation, done in Scilab, highlights the test responses of the process and, the speed control circuit implemented as block diagrams in Xcos, reveals the improve of the process parameter through the control loop.

  11. Evaluation of passive and active vibration control mechanisms in a microgravity environment

    Science.gov (United States)

    Ellison, J.; Ahmadi, G.; Grodsinsky, C.

    1993-01-01

    The behavior of equipment and their light secondary attachments in large space structures under orbital excitation is studied. The equipment is modeled as a shear beam and its secondary attachment is treated as a single-degree-of-freedom lumped mass system. Peak responses of the equipment and its secondary system for a variety of vibration control mechanisms are evaluated. A novel active friction control mechanism, by varying the normal force, is suggested. The device uses a magnetic field control to minimize the stick condition, thereby reducing the overall structural response. The results show that the use of the passive vibration control devices could reduce the peak equipment responses to a certain extent. However, major reduction of vibration levels could be achieved only by the use of active devices. Using active control of the interface normal force, the peak responses of the equipment and its attachment are reduced by a factor of 10 over the fixed-base equipment response.

  12. Flexible Concurrency Control for Legacy CAD to Construct Collaborative CAD Environment

    Science.gov (United States)

    Cai, Xiantao; Li, Xiaoxia; He, Fazhi; Han, Soonhung; Chen, Xiao

    Collaborative CAD (Co-CAD) systems can be constructed based on either 3D kernel or legacy stand-alone CAD systems, which are typically commercial CAD systems such as CATIA, Pro/E and so on. Most of synchronous Co-CAD systems, especially these based on legacy stand-alone CAD systems, adopt the lock mechanism or the floor control as concurrency controls which are very restrictive and stagnant. A flexible concurrency control method is proposed to support the flexible concurrency control in Co-CAD systems based on legacy stand-alone CAD systems. At first, a model of operation relationship is proposed with special consideration for the concurrency control of these kinds of Co-CAD system. Then two types of data structure, the Collaborative Feature Dependent Graph (Co-FDG) and the Collaborative Feature Operational List (Co-FOL), are presented as the cornerstone of flexible concurrency control. Next a Flexible Concurrency Control Algorithm (FCCA) is proposed. Finally a Selective Undo/Redo Algorithm is proposed which can improve the flexibility of Co-CAD furthermore.

  13. Research on Coordinated Robotic Motion Control Based on Fuzzy Decoupling Method in Fluidic Environments

    Directory of Open Access Journals (Sweden)

    Wei Zhang

    2014-01-01

    Full Text Available The underwater recovery of autonomous underwater vehicles (AUV is a process of 6-DOF motion control, which is related to characteristics with strong nonlinearity and coupling. In the recovery mission, the vehicle requires high level control accuracy. Considering an AUV called BSAV, this paper established a kinetic model to describe the motion of AUV in the horizontal plane, which consisted of nonlinear equations. On the basis of this model, the main coupling variables were analyzed during recovery. Aiming at the strong coupling problem between the heading control and sway motion, we designed a decoupling compensator based on the fuzzy theory and the decoupling theory. We analyzed to the rules of fuzzy compensation, the input and output membership functions of fuzzy compensator, through compose operation and clear operation of fuzzy reasoning, and obtained decoupling compensation quantity. Simulation results show that the fuzzy decoupling controller effectively reduces the overshoot of the system, and improves the control precision. Through the water tank experiments and analysis of experimental data, the effectiveness and feasibility of AUV recovery movement coordinated control based on fuzzy decoupling method are validated successful, and show that the fuzzy decoupling control method has a high practical value in the recovery mission.

  14. KALI - An environment for the programming and control of cooperative manipulators

    Science.gov (United States)

    Hayward, Vincent; Hayati, Samad

    1988-01-01

    A design description is given of a controller for cooperative robots. The background and motivation for multiple arm control are discussed. A set of programming primitives which permit a programmer to specify cooperative tasks are described. Motion primitives specify asynchronous motions, master/slave motions, and cooperative motions. In the context of cooperative robots, trajectory generation issues are discussed and the authors' implementation briefly described. The relations between programming and control in the case of multiple robots are examined. The allocation of various tasks among a multiprocessor computer is described.

  15. Feasibility of using combined EMG and kinematic signals for prosthesis control: A simulation study using a virtual reality environment.

    Science.gov (United States)

    Blana, Dimitra; Kyriacou, Theocharis; Lambrecht, Joris M; Chadwick, Edward K

    2016-08-01

    Transhumeral amputation has a significant effect on a person's independence and quality of life. Myoelectric prostheses have the potential to restore upper limb function, however their use is currently limited due to lack of intuitive and natural control of multiple degrees of freedom. The goal of this study was to evaluate a novel transhumeral prosthesis controller that uses a combination of kinematic and electromyographic (EMG) signals recorded from the person's proximal humerus. Specifically, we trained a time-delayed artificial neural network to predict elbow flexion/extension and forearm pronation/supination from six proximal EMG signals, and humeral angular velocity and linear acceleration. We evaluated this scheme with ten able-bodied subjects offline, as well as in a target-reaching task presented in an immersive virtual reality environment. The offline training had a target of 4° for flexion/extension and 8° for pronation/supination, which it easily exceeded (2.7° and 5.5° respectively). During online testing, all subjects completed the target-reaching task with path efficiency of 78% and minimal overshoot (1.5%). Thus, combining kinematic and muscle activity signals from the proximal humerus can provide adequate prosthesis control, and testing in a virtual reality environment can provide meaningful data on controller performance.

  16. Changing expression of vertebrate immunity genes in an anthropogenic environment: a controlled experiment.

    Science.gov (United States)

    Hablützel, Pascal I; Brown, Martha; Friberg, Ida M; Jackson, Joseph A

    2016-09-01

    The effect of anthropogenic environments on the function of the vertebrate immune system is a problem of general importance. For example, it relates to the increasing rates of immunologically-based disease in modern human populations and to the desirability of identifying optimal immune function in domesticated animals. Despite this importance, our present understanding is compromised by a deficit of experimental studies that make adequately matched comparisons between wild and captive vertebrates. We transferred post-larval fishes (three-spined sticklebacks), collected in the wild, to an anthropogenic (captive) environment. We then monitored, over 11 months, how the systemic expression of immunity genes changed in comparison to cohort-matched wild individuals in the originator population (total n = 299). We found that a range of innate (lyz, defbl2, il1r-like, tbk1) and adaptive (cd8a, igmh) immunity genes were up-regulated in captivity, accompanied by an increase in expression of the antioxidant enzyme, gpx4a. For some genes previously known to show seasonality in the wild, this appeared to be reduced in captive fishes. Captive fishes tended to express immunity genes, including igzh, foxp3b, lyz, defbl2, and il1r-like, more variably. Furthermore, although gene co-expression patterns (analyzed through gene-by-gene correlations and mutual information theory based networks) shared common structure in wild and captive fishes, there was also significant divergence. For one gene in particular, defbl2, high expression was associated with adverse health outcomes in captive fishes. Taken together, these results demonstrate widespread regulatory changes in the immune system in captive populations, and that the expression of immunity genes is more constrained in the wild. An increase in constitutive systemic immune activity, such as we observed here, may alter the risk of immunopathology and contribute to variance in health in vertebrate populations exposed to

  17. The fate of caesium-137 in a soil environment controlled by immobilization on clay minerals

    OpenAIRE

    NAKAO, Atsushi; Funakawa, Shinya; Tsukada, Hirofumi; Kosaki, Takashi

    2012-01-01

    Caesium-137 (137Cs), with its high release rate and long half life, is the most important longterm contributor to environmental contamination of all the radionuclides released by the accident at the Fukushima Dai-ichi nuclear power plant in March 2011. There have been many surveys of the fate of 137Cs in terrestrial environments, especially after the atmospheric nuclear tests of the 1950s and 60s and the Chernobyl accident in 1986. Previous surveys revealed that most of the 137Cs deposited on...

  18. Flammability control in the oxygen environment of the Apollo guidance and navigation equipment

    Science.gov (United States)

    Holley, M. D.; Bachman, S.

    1971-01-01

    The Apollo guidance and navigation (G&N) equipment test program, the redesign philosophy, and the actual equipment modifications that were used to limit burn rates in an environment of 100 percent oxygen at pressures of 6.2 and 16 psia are described. The major approach was a serious basic review of the real function of the nonmetallic materials of concern. The result of this review was that the materials could be replaced, eliminated, or covered by nonflammable metallic materials. Although several low-flammability nonmetallic materials were investigated, the direct approach of cover, eliminate, or replace generally proved to be quicker and more effective.

  19. Uncalibrated Visual Servo Control of Magnetically Actuated Microrobots in a Fluid Environment

    Directory of Open Access Journals (Sweden)

    Jenelle Armstrong Piepmeier

    2014-09-01

    Full Text Available Microrobots have a number of potential applications for micromanipulation and assembly, but also offer challenges in power and control. This paper describes an uncalibrated vision-based control system for magnetically actuated microrobots operating untethered at the interface between two immiscible fluids. The microrobots are 20 μm thick and approximately 100–200 μm in lateral dimension. Several different robot shapes are investigated. The robots and fluid are in a 20 × 20 × 15 mm vial placed at the center of four electromagnets. Pulse width modulation of the electromagnet currents is used to control robot speed and direction. Given a desired position, a controller based on recursive least square estimation drives the microrobot to the goal without a priori knowledge of system parameters such as drag coefficients or intrinsic and extrinsic camera parameters. Results are verified experimentally using a variety of microrobot shapes and system configurations.

  20. Coordinated Control of Multi-Agent Systems in Rapidly Varying Environments Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The main objective of this Phase II STTR project is to develop advanced control algorithms that enable multiple autonomous agents to perform complex tasks in rapidly...

  1. Temperature Field-Wind Velocity Field Optimum Control of Greenhouse Environment Based on CFD Model

    Directory of Open Access Journals (Sweden)

    Yongbo Li

    2014-01-01

    Full Text Available The computational fluid dynamics technology is applied as the environmental control model, which can include the greenhouse space. Basic environmental factors are set to be the control objects, the field information is achieved via the division of layers by height, and numerical characteristics of each layer are used to describe the field information. Under the natural ventilation condition, real-time requirements, energy consumption, and distribution difference are selected as index functions. The optimization algorithm of adaptive simulated annealing is used to obtain optimal control outputs. A comparison with full-open ventilation shows that the whole index can be reduced at 44.21% and found that a certain mutual exclusiveness exists between the temperature and velocity field in the optimal course. All the results indicate that the application of CFD model has great advantages to improve the control accuracy of greenhouse.

  2. Environment-insensitive and gate-controllable photocurrent enabled by bandgap engineering of MoS2 junctions

    Science.gov (United States)

    Shih, Fu-Yu; Wu, Yueh-Chun; Shih, Yi-Siang; Shih, Ming-Chiuan; Wu, Tsuei-Shin; Ho, Po-Hsun; Chen, Chun-Wei; Chen, Yang-Fang; Chiu, Ya-Ping; Wang, Wei-Hua

    2017-03-01

    Two-dimensional (2D) materials are composed of atomically thin crystals with an enormous surface-to-volume ratio, and their physical properties can be easily subjected to the change of the chemical environment. Encapsulation with other layered materials, such as hexagonal boron nitride, is a common practice; however, this approach often requires inextricable fabrication processes. Alternatively, it is intriguing to explore methods to control transport properties in the circumstance of no encapsulated layer. This is very challenging because of the ubiquitous presence of adsorbents, which can lead to charged-impurity scattering sites, charge traps, and recombination centers. Here, we show that the short-circuit photocurrent originated from the built-in electric field at the MoS2 junction is surprisingly insensitive to the gaseous environment over the range from a vacuum of 1 × 10-6  Torr to ambient condition. The environmental insensitivity of the short-circuit photocurrent is attributed to the characteristic of the diffusion current that is associated with the gradient of carrier density. Conversely, the photocurrent with bias exhibits typical persistent photoconductivity and greatly depends on the gaseous environment. The observation of environment-insensitive short-circuit photocurrent demonstrates an alternative method to design device structure for 2D-material-based optoelectronic applications.

  3. Analysis of Cisco Open Network Environment (ONE) OpenFlow Controller Implementation

    Science.gov (United States)

    2014-08-01

    or match criteria to ports that are not connected) as well as the ability to install and uninstall a flow from switches without deleting it entirely...Port recognition Not explicit Yes Install/ uninstall flows NA Yes Set dynamic flows Requires code manipulation Yes 6 5.2 OpenFlow Control Channel...Setup The initial handshake between the controller and switch was monitored using packet analysis tools capable of understanding OpenFlow protocol

  4. Can Modifications to the Bedroom Environment Improve the Sleep of New Parents? Two Randomized Controlled Trials

    OpenAIRE

    Lee, Kathryn A.; Gay, Caryl L.

    2010-01-01

    Postpartum sleep disruption is common among new parents. In this randomized controlled trial we evaluated a modified sleep hygiene intervention for new parents (infant proximity, noise masking, and dim lighting) in anticipation of night-time infant care. Two samples of new mothers (n = 118 and 122) were randomized to the experimental intervention or attention control, and sleep was assessed in late pregnancy and first 3 months postpartum using actigraphy and the General Sleep Disturbance Scal...

  5. How do people with persecutory delusions evaluate threat in a controlled social environment? A qualitative study using virtual reality.

    Science.gov (United States)

    Fornells-Ambrojo, Miriam; Freeman, Daniel; Slater, Mel; Swapp, David; Antley, Angus; Barker, Chris

    2015-01-01

    Environmental factors have been associated with psychosis but there is little qualitative research looking at how the ongoing interaction between individual and environment maintains psychotic symptoms. The current study investigates how people with persecutory delusions interpret events in a virtual neutral social environment using qualitative methodology. 20 participants with persecutory delusions and 20 controls entered a virtual underground train containing neutral characters. Under these circumstances, people with persecutory delusions reported similar levels of paranoia as non-clinical participants. The transcripts of a post-virtual reality interview of the first 10 participants in each group were analysed. Thematic analyses of interviews focusing on the decision making process associated with attributing intentions of computer-generated characters revealed 11 themes grouped in 3 main categories (evidence in favour of paranoid appraisals, evidence against paranoid appraisals, other behaviour). People with current persecutory delusions are able to use a range of similar strategies to healthy volunteers when making judgements about potential threat in a neutral environment that does not elicit anxiety, but they are less likely than controls to engage in active hypothesis-testing and instead favour experiencing "affect" as evidence of persecutory intention.

  6. Data communication between Panasonic PLC and PC using SerialPort control in C#.NET environment

    Science.gov (United States)

    Gao, Ting; Gan, Xiaochuan; Ma, Liqun

    2015-02-01

    With the gradual promotion of Microsoft.NET platform, C# as an object-oriented programming language based on the platform has been widely used. Therefore, more attention is concentrated on how to achieve the communication between Panasonic PLC and PC efficiently and fast in C#.NET environment. In this paper, a method of using SerialPort control which could be used for achieving communication between PLC and PC is introduced. Meanwhile, the reason of abnormal thread when displayed the receiving data in form is analyzed and the programming method to solve the problem of thread safety is designed. Achieving the communication of Panasonic PLC and PC in C#.NET environment can give full play to the advantages of the .NET framework. It is practical, easy communication, high reliability and can combine with other measurement and calibration procedures effectively and conveniently. Configuration software is expensive and can only communicate with PLC separately, but these shortcomings can be solved in C#.NET environment. A well-designed user interface realized real-time monitoring of PLC parameters and achieved management and control integration. The experiment show that this method of data transfer is accurate and the program' running is stable.

  7. Ion concentrations in seagrass: A comparison of results from field and controlled-environment studies

    Science.gov (United States)

    Garrote-Moreno, Aurora; Cambridge, Marion; Sánchez-Lizaso, Jose Luis

    2016-11-01

    Osmoregulation is essential for the survival of seagrasses in marine and hypersaline environments. The aim of this study was to examine ion concentrations of four seagrass species (Posidonia australis, P. sinuosa, Amphibolis antarctica and A. griffithii) after exposure to salinity changes. Plant fragments were placed in a series of aquaria at marine salinity (35) and, after one week of acclimation, exposed for 7 days to salinities between 20 and 70. Cl-, Na+ and total ion concentration increased with salinity in leaf tissue of the four seagrasses species. These results were compared with those of P. australis and A. antarctica samples collected at three locations at Shark Bay, Western Australia where higher salinities occurred, ranging from 46 to 51. Concentrations of K+ and Ca+2 were higher in seagrass tissues from Shark Bay than in those in aquarium trials. Cl-, Na+ and total ions in P. australis and A. antarctica from Shark Bay were lowest at the highest salinity location. The K+/Na+ ratio in the aquarium trials (under ambient conditions) was in the following order: A. antarctica = A. griffithii > P. australis > P. sinuosa and Ca+2/Na+ ratio was: A. antarctica = A. griffithii > P. sinuosa > P. australis. This species order indicates a physiological capacity to tolerate variation in salinity. Furthermore, these ratios were higher in the locality with highest salinity in Shark Bay, indicating acclimation and adaptation of ion concentrations to the salinity regime in the environment.

  8. Crystal structure control of aluminized clay minerals on the mobility of caesium in contaminated soil environments.

    Science.gov (United States)

    Dzene, Liva; Ferrage, Eric; Viennet, Jean-Christophe; Tertre, Emmanuel; Hubert, Fabien

    2017-02-24

    Radioactive caesium pollution resulting from Fukushima Dai-ichi and Chernobyl nuclear plant accidents involves strong interactions between Cs(+) and clays, especially vermiculite-type minerals. In acidic soil environments, such as in Fukushima area, vermiculite is subjected to weathering processes, resulting in aluminization. The crystal structure of aluminized clays and its implications for Cs(+) mobility in soils remain poorly understood due to the mixture of these minerals with other clays and organic matter. We performed acidic weathering of a vermiculite to mimic the aluminization process in soils. Combination of structure analysis and Cs(+) extractability measurements show that the increase of aluminization is accompanied by an increase in Cs(+) mobility. Crystal structure model for aluminized vermiculite is based on the interstratification of unaltered vermiculite layers and aluminized layers within the same particle. Cs(+) in vermiculite layers is poorly mobile, while the extractability of Cs(+) is greatly enhanced in aluminized layers. The overall reactivity of the weathered clay (cation exchange capacity, Cs(+) mobility) is then governed by the relative abundance of the two types of layers. The proposed layer model for aluminized vermiculite with two coexisting populations of caesium is of prime importance for predicting the fate of caesium in contaminated soil environments.

  9. Crystal structure control of aluminized clay minerals on the mobility of caesium in contaminated soil environments

    Science.gov (United States)

    Dzene, Liva; Ferrage, Eric; Viennet, Jean-Christophe; Tertre, Emmanuel; Hubert, Fabien

    2017-01-01

    Radioactive caesium pollution resulting from Fukushima Dai-ichi and Chernobyl nuclear plant accidents involves strong interactions between Cs+ and clays, especially vermiculite-type minerals. In acidic soil environments, such as in Fukushima area, vermiculite is subjected to weathering processes, resulting in aluminization. The crystal structure of aluminized clays and its implications for Cs+ mobility in soils remain poorly understood due to the mixture of these minerals with other clays and organic matter. We performed acidic weathering of a vermiculite to mimic the aluminization process in soils. Combination of structure analysis and Cs+ extractability measurements show that the increase of aluminization is accompanied by an increase in Cs+ mobility. Crystal structure model for aluminized vermiculite is based on the interstratification of unaltered vermiculite layers and aluminized layers within the same particle. Cs+ in vermiculite layers is poorly mobile, while the extractability of Cs+ is greatly enhanced in aluminized layers. The overall reactivity of the weathered clay (cation exchange capacity, Cs+ mobility) is then governed by the relative abundance of the two types of layers. The proposed layer model for aluminized vermiculite with two coexisting populations of caesium is of prime importance for predicting the fate of caesium in contaminated soil environments. PMID:28233805

  10. Crystal structure control of aluminized clay minerals on the mobility of caesium in contaminated soil environments

    Science.gov (United States)

    Dzene, Liva; Ferrage, Eric; Viennet, Jean-Christophe; Tertre, Emmanuel; Hubert, Fabien

    2017-02-01

    Radioactive caesium pollution resulting from Fukushima Dai-ichi and Chernobyl nuclear plant accidents involves strong interactions between Cs+ and clays, especially vermiculite-type minerals. In acidic soil environments, such as in Fukushima area, vermiculite is subjected to weathering processes, resulting in aluminization. The crystal structure of aluminized clays and its implications for Cs+ mobility in soils remain poorly understood due to the mixture of these minerals with other clays and organic matter. We performed acidic weathering of a vermiculite to mimic the aluminization process in soils. Combination of structure analysis and Cs+ extractability measurements show that the increase of aluminization is accompanied by an increase in Cs+ mobility. Crystal structure model for aluminized vermiculite is based on the interstratification of unaltered vermiculite layers and aluminized layers within the same particle. Cs+ in vermiculite layers is poorly mobile, while the extractability of Cs+ is greatly enhanced in aluminized layers. The overall reactivity of the weathered clay (cation exchange capacity, Cs+ mobility) is then governed by the relative abundance of the two types of layers. The proposed layer model for aluminized vermiculite with two coexisting populations of caesium is of prime importance for predicting the fate of caesium in contaminated soil environments.

  11. Steady-State VEP-Based Brain-Computer Interface Control in an Immersive 3D Gaming Environment

    Directory of Open Access Journals (Sweden)

    Burke R

    2005-01-01

    Full Text Available This paper presents the application of an effective EEG-based brain-computer interface design for binary control in a visually elaborate immersive 3D game. The BCI uses the steady-state visual evoked potential (SSVEP generated in response to phase-reversing checkerboard patterns. Two power-spectrum estimation methods were employed for feature extraction in a series of offline classification tests. Both methods were also implemented during real-time game play. The performance of the BCI was found to be robust to distracting visual stimulation in the game and relatively consistent across six subjects, with 41 of 48 games successfully completed. For the best performing feature extraction method, the average real-time control accuracy across subjects was 89%. The feasibility of obtaining reliable control in such a visually rich environment using SSVEPs is thus demonstrated and the impact of this result is discussed.

  12. Occupant preferences and satisfaction with the luminous environment and control systems in daylit offices: a literature review

    Energy Technology Data Exchange (ETDEWEB)

    Galasiu, A.D.; Veitch, J.A. [Indoor Environment Research Programme, Institute for Research in Construction, National Research Council Canada, Ottawa, Ontario (Canada)

    2006-07-01

    This paper presents an overview of peer-reviewed investigations of subjective issues linked to the use of daylighting in office buildings, particularly studies of preferred physical and luminous conditions in daylit office environments, and studies of occupant satisfaction and acceptance of electric lighting and window shading controls. The literature shows a consistent strong preference for daylight and a wide distribution between individuals in relation to the preferred illuminance levels in daylit offices. Existing knowledge about how people respond to daylight-linked lighting and shading controls in the workplace is very limited; therefore, this paper presents a summary of knowledge gaps in the field of daylighting and its interaction with the occupants. The resulting key directions for future research highlight issues for which a better understanding is required for the development of lighting and window shading control systems that are both energy efficient and suitable for the office occupants. (author)

  13. Steady-State VEP-Based Brain-Computer Interface Control in an Immersive 3D Gaming Environment

    Science.gov (United States)

    Lalor, E. C.; Kelly, S. P.; Finucane, C.; Burke, R.; Smith, R.; Reilly, R. B.; McDarby, G.

    2005-12-01

    This paper presents the application of an effective EEG-based brain-computer interface design for binary control in a visually elaborate immersive 3D game. The BCI uses the steady-state visual evoked potential (SSVEP) generated in response to phase-reversing checkerboard patterns. Two power-spectrum estimation methods were employed for feature extraction in a series of offline classification tests. Both methods were also implemented during real-time game play. The performance of the BCI was found to be robust to distracting visual stimulation in the game and relatively consistent across six subjects, with 41 of 48 games successfully completed. For the best performing feature extraction method, the average real-time control accuracy across subjects was 89%. The feasibility of obtaining reliable control in such a visually rich environment using SSVEPs is thus demonstrated and the impact of this result is discussed.

  14. The Influence of Parental Self-Efficacy and Perceived Control on the Home Learning Environment of Young Children.

    Science.gov (United States)

    Peacock-Chambers, Elizabeth; Martin, Justin T; Necastro, Kelly A; Cabral, Howard J; Bair-Merritt, Megan

    2017-03-01

    To: 1) examine sociodemographic factors associated with high parental self-efficacy and perceived control, and 2) determine how self-efficacy and control relate to the home learning environment (HLE), including whether they mediate the relationship between sociodemographic characteristics and HLE, among low-income parents of young children. Cross-sectional survey of English- and Spanish-speaking parents, 18 years of age and older, with children 15 to 36 months old, to assess parental self-efficacy, perceived control, HLE, and sociodemographic characteristics. Bivariate analysis identified sociodemographic predictors of high self-efficacy and control. Separate multivariate linear regression models were used to examine associations between self-efficacy, control, and the HLE. Formal path analysis was used to assess whether self-efficacy and control mediate the relationship between sociodemographic characteristics and HLE. Of 144 participants, 25% were white, 65% were immigrants, and 35% completed the survey in Spanish. US-born subjects, those who completed English surveys, or who had higher educational levels had significantly higher mean self-efficacy and perceived control scores (P self-efficacy and perceived control were associated with a positive change in HLE score in separate multivariate models (self-efficacy β = .7 [95% confidence interval (CI), 0.5-0.9]; control β = .5 [95% CI, 0.2-0.8]). Self-efficacy acted as a mediator such that low self-efficacy explained part of the association between parental depressive symptoms, immigrant status, and less optimal HLE (P = .04 and self-efficacy and perceived control positively influence HLEs of young children. Self-efficacy alone mediates the relationship between parental depressive symptoms, immigrant status, and less optimal early home learning. Copyright © 2016 Academic Pediatric Association. Published by Elsevier Inc. All rights reserved.

  15. A remote control training system for rat navigation in complicated environment

    Institute of Scientific and Technical Information of China (English)

    FENG Zhou-yan; LIU Chun-qing; LIU Fu-xin; LUO Jian-hong; ZHUANG Yue-ting; ZHENG Xiao-xiang; CHEN Wei-dong; YE Xue-song; ZHANG Shao-min; ZHENG Xiao-jing; WANG Peng; JIANG Jun; JIN Lin; XU Zhi-jian

    2007-01-01

    A remote control system has been developed to deliver stimuli into the rat brain through a wireless micro-stimulator for animal behavior training. The system consists of the following main components: an integrated PC control program, a transmitter and a receiver based on Bluetooth (BT) modules, a stimulator controlled by C8051 microprocessor, as well as an operant chamber and an eight-arm radial maze. The micro-stimulator is featured with its changeable amplitude of pulse output for both constant-voltage and constant-current mode, which provides an easy way to set the proper suitable stimulation intensity for different training. The system has been used in behavior experiments for monitoring and recording bar-pressing in the operant chamber, controlling rat roaming in the eight-arm maze, as well as navigating rats through a 3D obstacle route. The results indicated that the system worked stably and that the stimulation was effective for different types of rat behavior controls. In addition, the results showed that stimulation in the whisker barrel region of rat primary somatosensory cortex (SI) acted like a cue. The animals can be trained to take different desired turns upon the association between the SI cue stimulation and the reward stimulation in the medial forebrain bundle (MFB).

  16. A novel approach to determine the efficacy of patterned surfaces for biofouling control in relation to its microfluidic environment.

    Science.gov (United States)

    Halder, Partha; Nasabi, Mahyar; Lopez, Francisco Javier Tovar; Jayasuriya, Niranjali; Bhattacharya, Satinath; Deighton, Margaret; Mitchell, Arnan; Bhuiyan, Muhammed Ali

    2013-01-01

    Biofouling, the unwanted growth of sessile microorganisms on submerged surfaces, presents a serious problem for underwater structures. While biofouling can be controlled to various degrees with different microstructure-based patterned surfaces, understanding of the underlying mechanism is still imprecise. Researchers have long speculated that microtopographies might influence near-surface microfluidic conditions, thus microhydrodynamically preventing the settlement of microorganisms. It is therefore very important to identify the microfluidic environment developed on patterned surfaces and its relation with the antifouling behaviour of those surfaces. This study considered the wall shear stress distribution pattern as a significant aspect of this microfluidic environment. In this study, patterned surfaces with microwell arrays were assessed experimentally with a real-time biofilm development monitoring system using a novel microchannel-based flow cell reactor. Finally, computational fluid dynamics simulations were carried out to show how the microfluidic conditions were affecting the initial settlement of microorganisms.

  17. Differential Evolution Based Receding Horizon Control for UAV Motion Planning in Dynamic Environments

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xing; BAI YongQiang; XIN Bin; CHEN Jie

    2013-01-01

    This paper presents online motion planning for UAV (unmanned aerial vehicle) in complex threat field,including both static threats and moving threats,which can be formulated as a dynamic constrained optimal control problem.Receding horizon control (RHC) based on differential evolution (DE) algorithm is adopted.A location-predicting model of moving threats is established to assess the value of threat that UAV faces in flight.Then flyable paths can be generated by the control inputs which are optimized by DE under the guidance of the objective function.Simulation results demonstrate that the proposed method not only generates smooth and flyable paths,but also enables UAV to avoid threats efficiently and arrive at destination safely.

  18. RSSI/LQI-based transmission power control for body area networks in healthcare environment.

    Science.gov (United States)

    Kim, Seungku; Kim, Seokhwan; Eom, Doo-Seop

    2013-05-01

    This paper presents a novel transmission power control protocol for body area networks. Conventional transmission power control protocols adjust the transmission power on the basis of the received signal strength indication (RSSI). However, in case of the presence of interference, the RSSI is not a correct indicator to determine the link state. We first present the empirical evidence for this and then propose a practical protocol to discriminate between the signal attenuation and interference using the RSSI and link quality indication (LQI). This protocol controls the transmission power and avoids interference based on the link state. Finally, we discuss the implementation of the proposed protocol on Tmote Sky and evaluate the performance in the presence and absence of interference. The experimental results showed that the proposed protocol has high energy-efficiency and reliability, even in the presence of interference.

  19. The influence of socioeconomic environment on the effectiveness of alcohol prevention among European students: a cluster randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Faggiano Fabrizio

    2011-05-01

    Full Text Available Abstract Background Although social environments may influence alcohol-related behaviours in youth, the relationship between neighbourhood socioeconomic context and effectiveness of school-based prevention against underage drinking has been insufficiently investigated. We study whether the social environment affects the impact of a new school-based prevention programme on alcohol use among European students. Methods During the school year 2004-2005, 7079 students 12-14 years of age from 143 schools in nine European centres participated in this cluster randomised controlled trial. Schools were randomly assigned to either control or a 12-session standardised curriculum based on the comprehensive social influence model. Randomisation was blocked within socioeconomic levels of the school environment. Alcohol use and alcohol-related problem behaviours were investigated through a self-completed anonymous questionnaire at baseline and 18 months thereafter. Data were analysed using multilevel models, separately by socioeconomic level. Results At baseline, adolescents in schools of low socioeconomic level were more likely to report problem drinking than other students. Participation in the programme was associated in this group with a decreased odds of reporting episodes of drunkenness (OR = 0.60, 95% CI = 0.44-0.83, intention to get drunk (OR = 0.60, 95% CI = 0.45-0.79, and marginally alcohol-related problem behaviours (OR = 0.70, 95% CI = 0.46-1.06. No significant programme's effects emerged for students in schools of medium or high socioeconomic level. Effects on frequency of alcohol consumption were also stronger among students in disadvantaged schools, although the estimates did not attain statistical significance in any subgroup. Conclusions It is plausible that comprehensive social influence programmes have a more favourable effect on problematic drinking among students in underprivileged social environments. Trial registration ISRCTN: ISRCTN

  20. Using the CERN generic Windows infrastructure in a specific control environment

    CERN Document Server

    Deloose, I; Pace, A

    1999-01-01

    CERN has a large Windows 95/NT infrastructure with more than 3500 PCs connected that is used as one of the main information services for the laboratory. This infrastructure is used for a wide set of services, including Office Automation, Computing Aided Engineering, Calculations, Software Development, and ... controls. This paper will describe the CERN generic infrastructure for Windows 95 and Windows NT and then give several examples of PC control applications and future directions. The implementation of an object oriented device server based on Windows NT and ActiveX in the CERN ISOLDE-REX experiment will be reported.