Science.gov

Sample records for agent cwa simulants

  1. Array of Love-wave sensors based on quartz/Novolac to detect CWA simulants.

    PubMed

    Matatagui, D; Fontecha, J; Fernández, M J; Aleixandre, M; Gràcia, I; Cané, C; Horrillo, M C

    2011-09-15

    An array of Love-wave sensors based on quartz and Novolac has been developed to detect chemical warfare agents (CWAs). These weapons are a risk for human health due to their efficiency and high lethality; therefore an early and clear detection is of enormous importance for the people safety. Love-wave devices realized on quartz as piezoelectric substrate and Novolac as guiding layer have been used to make up an array of six sensors, which have been coated with specific polymers by spin coating. The CWAs are very dangerous and for safety reasons their well known simulants have been used: dimethylmethyl phosphonate (DMMP), dipropyleneglycol methyl ether (DPGME), dimethylmethyl acetamide (DMA), dichloroethane (DCE), dichloromethane (DCM) and dichloropentane (DCP). The array has been exposed to these CWA simulants detecting very low concentrations, such as 25 ppb of DMMP, a simulant of nerve agent sarin. Finally, principal component analysis (PCA) as data pre-processing and discrimination technique, and probabilistic neural networks (PNN) as patterns classification technique have been applied. The performance of the sensor array has shown stability, accuracy, high sensitivity and good selectivity to these simulants. PMID:21807207

  2. Reactive skin decontamination lotion (RSDL) for the decontamination of chemical warfare agent (CWA) dermal exposure.

    PubMed

    Schwartz, M D; Hurst, C G; Kirk, M A; Reedy, S J D; Braue, E H

    2012-08-01

    Rapid decontamination of the skin is the single most important action to prevent dermal absorption of chemical contaminants in persons exposed to chemical warfare agents (CWA) and toxic industrial chemicals (TICs) as a result of accidental or intentional release. Chemicals on the skin may be removed by mechanical means through the use of dry sorbents or water. Recent interest in decontamination systems which both partition contaminants away from the skin and actively neutralize the chemical has led to the development of several reactive decontamination solutions. This article will review the recently FDA-approved Reactive Skin Decontamination Lotion (RSDL) and will summarize the toxicity and efficacy studies conducted to date. Evidence of RSDL's superior performance against vesicant and organophosphorus chemical warfare agents compared to water, bleach, and dry sorbents, suggests that RSDL may have a role in mass human exposure chemical decontamination in both the military and civilian arenas. PMID:22352732

  3. Direct and Sensitive Detection of CWA Simulants by Active Capillary Plasma Ionization Coupled to a Handheld Ion Trap Mass Spectrometer

    NASA Astrophysics Data System (ADS)

    Wolf, Jan-Christoph; Etter, Raphael; Schaer, Martin; Siegenthaler, Peter; Zenobi, Renato

    2016-07-01

    An active capillary plasma ionization (ACI) source was coupled to a handheld mass spectrometer (Mini 10.5; Aston Labs, West Lafayette, IN, USA) and applied to the direct gas-phase detection and quantification of chemical warfare agent (CWA) related chemicals. Complementing the discontinuous atmospheric pressure interface (DAPI) of the Mini 10.5 mass spectrometer with an additional membrane pump, a quasi-continuous sample introduction through the ACI source was achieved. Nerve agent simulants (three dialkyl alkylphosphonates, a dialkyl phosporamidate, and the pesticide dichlorvos) were detected at low gas-phase concentrations with limits of detection ranging from 1.0 μg/m3 to 6.3 μg/m3. Our results demonstrate a sensitivity enhancement for portable MS-instrumentation by using an ACI source, enabling direct, quantitative measurements of volatile organic compounds. Due to its high sensitivity, selectivity, low power consumption (<80 W) and weight (<13 kg), this instrumentation has the potential for direct on-site CWA detection as required by military or civil protection.

  4. Direct and Sensitive Detection of CWA Simulants by Active Capillary Plasma Ionization Coupled to a Handheld Ion Trap Mass Spectrometer

    NASA Astrophysics Data System (ADS)

    Wolf, Jan-Christoph; Etter, Raphael; Schaer, Martin; Siegenthaler, Peter; Zenobi, Renato

    2016-03-01

    An active capillary plasma ionization (ACI) source was coupled to a handheld mass spectrometer (Mini 10.5; Aston Labs, West Lafayette, IN, USA) and applied to the direct gas-phase detection and quantification of chemical warfare agent (CWA) related chemicals. Complementing the discontinuous atmospheric pressure interface (DAPI) of the Mini 10.5 mass spectrometer with an additional membrane pump, a quasi-continuous sample introduction through the ACI source was achieved. Nerve agent simulants (three dialkyl alkylphosphonates, a dialkyl phosporamidate, and the pesticide dichlorvos) were detected at low gas-phase concentrations with limits of detection ranging from 1.0 μg/m3 to 6.3 μg/m3. Our results demonstrate a sensitivity enhancement for portable MS-instrumentation by using an ACI source, enabling direct, quantitative measurements of volatile organic compounds. Due to its high sensitivity, selectivity, low power consumption (<80 W) and weight (<13 kg), this instrumentation has the potential for direct on-site CWA detection as required by military or civil protection.

  5. Direct and Sensitive Detection of CWA Simulants by Active Capillary Plasma Ionization Coupled to a Handheld Ion Trap Mass Spectrometer.

    PubMed

    Wolf, Jan-Christoph; Etter, Raphael; Schaer, Martin; Siegenthaler, Peter; Zenobi, Renato

    2016-07-01

    An active capillary plasma ionization (ACI) source was coupled to a handheld mass spectrometer (Mini 10.5; Aston Labs, West Lafayette, IN, USA) and applied to the direct gas-phase detection and quantification of chemical warfare agent (CWA) related chemicals. Complementing the discontinuous atmospheric pressure interface (DAPI) of the Mini 10.5 mass spectrometer with an additional membrane pump, a quasi-continuous sample introduction through the ACI source was achieved. Nerve agent simulants (three dialkyl alkylphosphonates, a dialkyl phosporamidate, and the pesticide dichlorvos) were detected at low gas-phase concentrations with limits of detection ranging from 1.0 μg/m(3) to 6.3 μg/m(3). Our results demonstrate a sensitivity enhancement for portable MS-instrumentation by using an ACI source, enabling direct, quantitative measurements of volatile organic compounds. Due to its high sensitivity, selectivity, low power consumption (<80 W) and weight (<13 kg), this instrumentation has the potential for direct on-site CWA detection as required by military or civil protection. Graphical Abstract ᅟ. PMID:27020924

  6. Stand-off CWA imaging system: second sight MS

    NASA Astrophysics Data System (ADS)

    Bernascolle, Philippe F.; Elichabe, Audrey; Fervel, Franck; Haumonté, Jean-Baptiste

    2012-06-01

    In recent years, several manufactures of IR imaging devices have launched commercial models applicable to a wide range of chemical species. These cameras are rugged and sufficiently sensitive to detect low concentrations of toxic and combustible gases. Bertin Technologies, specialized in the design and supply of innovating systems for industry, defense and health, has developed a stand-off gas imaging system using a multi-spectral infrared imaging technology. With this system, the gas cloud size, localization and evolution can be displayed in real time. This technology was developed several years ago in partnership with the CEB, a French MoD CBRN organization. The goal was to meet the need for early warning caused by a chemical threat. With a night & day efficiency of up to 5 km, this process is able to detect Chemical Warfare Agents (CWA), critical Toxic Industrial Compounds (TIC) and also flammable gases. The system has been adapted to detect industrial spillage, using off-the-shelf uncooled infrared cameras, allowing 24/7 surveillance without costly frequent maintenance. The changes brought to the system are in compliance with Military Specifications (MS) and primarily focus on the signal processing improving the classification of the detected products and on the simplification of the Human Machine Interface (HMI). Second Sight MS is the only mass produced, passive stand-off CWA imaging system with a wide angle (up to 60°) already used by several regular armies around the world. This paper examines this IR gas imager performance when exposed to several CWA, TIC and simulant compounds. First, we will describe the Second Sight MS system. The theory of gas detection, visualization and classification functions has already been described elsewhere, so we will just summarize it here. We will then present the main topic of this paper which is the results of the tests done in laboratory on live agents and in open field on simulant. The sensitivity threshold of the

  7. OCEAN DISCHARGE CRITERIA DATABASE (CWA SECTION 403)

    EPA Science Inventory

    Resource Purpose:Under Section 402 of the CWA, NPDES permits addressing discharges to the ocean can be obtained. Also under the NPDES program, facilities that discharge beyond the baseline must obtain in addition to NPDES permit under CWA Section 402, that permit must also...

  8. Secondary ionization of chemical warfare agent simulants: atmospheric pressure ion mobility time-of-flight mass spectrometry.

    PubMed

    Steiner, Wes E; Clowers, Brian H; Haigh, Paul E; Hill, Herbert H

    2003-11-15

    For the first time, the use of a traditional ionization source for ion mobility spectrometry (radioactive nickel ((63)Ni) beta emission ionization) and three alternative ionization sources (electrospray ionization (ESI), secondary electrospray ionization (SESI), and electrical discharge (corona) ionization (CI)) were employed with an atmospheric pressure ion mobility orthogonal reflector time-of-flight mass spectrometer (IM(tof)MS) to detect chemical warfare agent (CWA) simulants from both aqueous- and gas-phase samples. For liquid-phase samples, ESI was used as the sample introduction and ionization method. For the secondary ionization (SESI, CI, and traditional (63)Ni ionization) of vapor-phase samples, two modes of sample volatilization (heated capillary and thermal desorption chamber) were investigated. Simulant reference materials, which closely mimic the characteristic chemical structures of CWA as defined and described by Schedule 1, 2, or 3 of the Chemical Warfare Convention treaty verification, were used in this study. A mixture of four G/V-type nerve simulants (dimethyl methylphosphonate, pinacolyl methylphosphonate, diethyl phosphoramidate, and 2-(butylamino)ethanethiol) and one S-type vesicant simulant (2-chloroethyl ethyl sulfide) were found in each case (sample ionization and introduction methods) to be clearly resolved using the IM(tof)MS method. In many cases, reduced mobility constants (K(o)) were determined for the first time. Ion mobility drift times, flight times, relative signal intensities, and fragmentation product signatures for each of the CWA simulants are reported for each of the methods investigated. PMID:14615983

  9. Detection and monitoring of CWA and BWA using LIBS

    NASA Astrophysics Data System (ADS)

    Landström, L.; Larsson, A.; Gradmark, P.-Å.; Örebrand, Lillermor; Andersson, P. O.; Wästerby, Pär.; Tjärnhage, Torbjörn

    2014-05-01

    Results related to laser induced breakdown spectroscopy (LIBS) as an analytical tool for applications regarding CWA and BWA detection/monitoring will be presented and discussed in this paper. A `real-time' aerosol analysis set-up using LIBS on single μm-sized particles (sampled from ambient air into a particle stream) has been developed and evaluated. Here, a two-stage triggering unit ensures a high hit-rate of the sampled aerosol particles and the optical emission from the laser induced plasma is collected and coupled into an echelle spectrometer equipped with an intensified CCD detector. Each CCD image (echellogram), optimally originating from a single μm-sized particle, is then analyzed and the result treated by an alarm algorithm built from a database using multivariate data analysis. The database signatures of simulant agents and interferents were obtained in controlled atmospheres (aerosol chamber/wind tunnel) as well as from measurements in different ambient background. The LIBS bioaerosol system with alarm algorithm was also tested in `real-life' settings (subway station) during simulant dispersions. Painted surfaces have also been analyzed by LIBS to obtain information about residues of organophosphates on, or within, the paint. Depth analysis has been performed, which illustrated the possibility to monitor diffusion and penetration behavior of neat CWAs and simulant chemicals in the paint layer by following the intensity of phosphorous emission lines in single shot LIBS spectra as function of number of laser pulses. In addition, LIBS analysis was also performed after simple ethanol decontamination procedures, after which P emission lines still could be observed. The possibilities and challenges associated with the different set-ups and applications will be briefly discussed in connection with the presented results.

  10. Chemistry of destroying chemical warfare agents in flame. Technical project report, April 1994-May 1995

    SciTech Connect

    Korobeinichev, O.P.; Chernov, A.A.; Shvartsberg, V.M.; Il`in, S.B.; Mokrushin, V.V.

    1995-05-01

    The goal of the research is to increase our understanding of flame chemistry of organophosphorus compounds (OPC). This class of chemicals includes chemical warfare agents. (CWAs) such as the nerve agents GB GD and VX, stockpiles of which in the United States and Former Soviet Union are scheduled for destruction by incineration or other technologies. Although high CWA destruction efficiency has been demonstrated in incinerator tests in the U.S. it is necessary to improve technology for achievement higher efficiency and lower level of pollutants. The knowledge of detailed destruction chemistry of the CWA and simulants can be obtained by studying the structure of flames, doped with simulants and CWA and by the development of the combustion model which will include the chemical mechanism of destroying CWA in flame. Alkyl phosphates and alkyl phosphonates are typical organophosphorus compounds, that are simulants of sarin.

  11. Single-particle aerosol mass spectrometry for the detection and identification of chemical warfare agent simulants.

    PubMed

    Martin, Audrey N; Farquar, George R; Frank, Matthias; Gard, Eric E; Fergenson, David P

    2007-08-15

    Single-particle aerosol mass spectrometry (SPAMS) was used for the real-time detection of liquid nerve agent simulants. A total of 1000 dual-polarity time-of-flight mass spectra were obtained for micrometer-sized single particles each of dimethyl methyl phosphonate, diethyl ethyl phosphonate, diethyl phosphoramidate, and diethyl phthalate using laser fluences between 0.58 and 7.83 nJ/microm2, and mass spectral variation with laser fluence was studied. The mass spectra obtained allowed identification of single particles of the chemical warfare agent (CWA) simulants at each laser fluence used although lower laser fluences allowed more facile identification. SPAMS is presented as a promising real-time detection system for the presence of CWAs. PMID:17630721

  12. Graphene oxide as sensitive layer in Love-wave surface acoustic wave sensors for the detection of chemical warfare agent simulants.

    PubMed

    Sayago, Isabel; Matatagui, Daniel; Fernández, María Jesús; Fontecha, José Luis; Jurewicz, Izabela; Garriga, Rosa; Muñoz, Edgar

    2016-02-01

    A Love-wave device with graphene oxide (GO) as sensitive layer has been developed for the detection of chemical warfare agent (CWA) simulants. Sensitive films were fabricated by airbrushing GO dispersions onto Love-wave devices. The resulting Love-wave sensors detected very low CWA simulant concentrations in synthetic air at room temperature (as low as 0.2 ppm for dimethyl-methylphosphonate, DMMP, a simulant of sarin nerve gas, and 0.75 ppm for dipropylene glycol monomethyl ether, DPGME, a simulant of nitrogen mustard). High responses to DMMP and DPGME were obtained with sensitivities of 3087 and 760 Hz/ppm respectively. Very low limit of detection (LOD) values (9 and 40 ppb for DMMP and DPGME, respectively) were calculated from the achieved experimental data. The sensor exhibited outstanding sensitivity, good linearity and repeatability to all simulants tested. The detection mechanism is here explained in terms of hydrogen bonding formation between the tested CWA simulants and GO. PMID:26653465

  13. Validation of an evacuated canister method for measuring part-per-billion levels of chemical warfare agent simulants.

    PubMed

    Coffey, Christopher C; LeBouf, Ryan F; Calvert, Catherine A; Slaven, James E

    2011-08-01

    The National Institute for Occupational Safety and Health (NIOSH) research on direct-reading instruments (DRIs) needed an instantaneous sampling method to provide independent confirmation of the concentrations of chemical warfare agent (CWA) simulants. It was determined that evacuated canisters would be the method of choice. There is no method specifically validated for volatile organic compounds (VOCs) in the NIOSH Manual of Analytical Methods. The purpose of this study was to validate an evacuated canister method for sampling seven specific VOCs that can be used as a simulant for CWA agents (cyclohexane) or influence the DRI measurement of CWA agents (acetone, chloroform, methylene chloride, methyl ethyl ketone, hexane, and carbon tetrachloride [CCl4]). The method used 6-L evacuated stainless-steel fused silica-lined canisters to sample the atmosphere containing VOCs. The contents of the canisters were then introduced into an autosampler/preconcentrator using a microscale purge and trap (MPT) method. The MPT method trapped and concentrated the VOCs in the air sample and removed most of the carbon dioxide and water vapor. After preconcentration, the samples were analyzed using a gas chromatograph with a mass selective detector. The method was tested, evaluated, and validated using the NIOSH recommended guidelines. The evaluation consisted of determining the optimum concentration range for the method; the sample stability over 30 days; and the accuracy, precision, and bias of the method. This method meets the NIOSH guidelines for six of the seven compounds (excluding acetone) tested in the range of 2.3-50 parts per billion (ppb), making it suitable for sampling of these VOCs at the ppb level. PMID:21874953

  14. Ultratrace detection of chemical warfare agent simulants using supersonic-molecular-beam, resonance-enhanced multiphoton-ionization, time-of-flight mass spectroscopy. Final report

    SciTech Connect

    Syage, J.A.; Pollard, J.E.; Cohen, R.B.

    1988-02-15

    An ultratrace detection method that offers exceptional selectivity has been developed based on the technique of supersonic molecular beam, resonance enhanced multiphoton ionization, time-of-flight mass spectroscopy (MB/REMPI/TOFMS). Single ion detection capability has given detection limits as low as 300 ppt (dimethyl sulfide). Single vibronic level REMPI of the supercooled molecules in conjunction with TOFMS provides selectivity of 10,000 against chemically similar compounds. Studies were carried out using moist air expansions for a variety of organophosphonate and sulfide chemical warfare agent (CWA) simulant molecules. The preparation of molecules in single vibronic levels by laser excitation in supersonic molecular beams has enabled us to record high resolution spectra of higher excited electronic states showing fully resolved vibrational structure for diisopropyl methylphosphonate (DIMP) and dimethyl sulfide (DMS). VUV absorption spectra have also been recorded for several CWA molecules at ambient temperature, revealing several new electronic states extending up to the ionization threshold.

  15. Facility monitoring of chemical warfare agent simulants in air using an automated, field-deployable, miniature mass spectrometer.

    PubMed

    Smith, Jonell N; Noll, Robert J; Cooks, R Graham

    2011-05-30

    Vapors of four chemical warfare agent (CWA) stimulants, 2-chloroethyl ethyl sulfide (CEES), diethyl malonate (DEM), dimethyl methylphosphonate (DMMP), and methyl salicylate (MeS), were detected, identified, and quantitated using a fully automated, field-deployable, miniature mass spectrometer. Samples were ionized using a glow discharge electron ionization (GDEI) source, and ions were mass analyzed with a cylindrical ion trap (CIT) mass analyzer. A dual-tube thermal desorption system was used to trap compounds on 50:50 Tenax TA/Carboxen 569 sorbent before their thermal release. The sample concentrations ranged from low parts per billion [ppb] to two parts per million [ppm]. Limits of detection (LODs) ranged from 0.26 to 5.0 ppb. Receiver operating characteristic (ROC) curves are presented for each analyte. A sample of CEES at low ppb concentration was combined separately with two interferents, bleach (saturated vapor) and diesel fuel exhaust (1%), as a way to explore the capability of detecting the simulant in an environmental matrix. Also investigated was a mixture of the four CWA simulants (at concentrations in air ranging from 270 to 380 ppb). Tandem mass (MS/MS) spectral data were used to identify and quantify the individual components. PMID:21504010

  16. Mechanistic insights into the luminescent sensing of organophosphorus chemical warfare agents and simulants using trivalent lanthanide complexes.

    PubMed

    Dennison, Genevieve H; Johnston, Martin R

    2015-04-20

    Organophosphorus chemical warfare agents (OP CWAs) are potent acetylcholinesterase inhibitors that can cause incapacitation and death within minutes of exposure, and furthermore are largely undetectable by the human senses. Fast, efficient, sensitive and selective detection of these compounds is therefore critical to minimise exposure. Traditional molecular-based sensing approaches have exploited the chemical reactivity of the OP CWAs, whereas more recently supramolecular-based approaches using non-covalent interactions have gained momentum. This is due, in part, to the potential development of sensors with second-generation properties, such as reversibility and multifunction capabilities. Supramolecular sensors also offer opportunities for incorporation of metal ions allowing for the exploitation of their unique properties. In particular, trivalent lanthanide ions are being increasingly used in the OP CWA sensing event and their use in supramolecular sensors is discussed in this Minireview. We focus on the fundamental interactions of simple lanthanide systems with OP CWAs and simulants, along with the development of more elaborate and complex systems including those containing nanotubes, polymers and gold nanoparticles. Whilst literature investigations into lanthanide-based OP CWA detection systems are relatively scarce, their unique and versatile properties provide a promising platform for the development of more efficient and complex sensing systems into the future. PMID:25649522

  17. High-separation efficiency micro-fabricated multi-capillary gas chromatographic columns for simulants of the nerve agents and blister agents

    PubMed Central

    2014-01-01

    To achieve both high speed and separation efficiency in the separation of a mixture of nerve and blister agent simulants, a high-aspect-ratio micro-fabricated multi-capillary column (MCC, a 50-cm-long, 450-μm-deep, and 60-μm-wide four-capillary column) was fabricated by the application of the microelectromechanical system (MEMS) techniques. Mixtures of chemical warfare agent (CWA) simulants - dimethyl methylphosphonate (DMMP), triethyl phosphate (TEP), and methyl salicylate - were used as samples. The fabricated MCC allowed for the separation of all the components of the gaseous mixture within 24 s, even when the difference in boiling point was 4°C, as in the case of TEP and methyl salicylate. Furthermore, interfering agents - dichloromethane, ethanol, and toluene - were also included in the subsequent gaseous mixture samples. The boiling point of these six components ranged from 78°C to 219°C. All six components were clearly separated within 70 s. This study is the first to report the clear separation of gas mixtures of components with close boiling points. The column efficiency was experimentally determined to be 12,810 plates/m. PMID:24899869

  18. High-separation efficiency micro-fabricated multi-capillary gas chromatographic columns for simulants of the nerve agents and blister agents

    NASA Astrophysics Data System (ADS)

    Li, Yi; Du, Xiaosong; Wang, Yang; Tai, Huiling; Qiu, Dong; Lin, Qinghao; Jiang, Yadong

    2014-05-01

    To achieve both high speed and separation efficiency in the separation of a mixture of nerve and blister agent simulants, a high-aspect-ratio micro-fabricated multi-capillary column (MCC, a 50-cm-long, 450-μm-deep, and 60-μm-wide four-capillary column) was fabricated by the application of the microelectromechanical system (MEMS) techniques. Mixtures of chemical warfare agent (CWA) simulants - dimethyl methylphosphonate (DMMP), triethyl phosphate (TEP), and methyl salicylate - were used as samples. The fabricated MCC allowed for the separation of all the components of the gaseous mixture within 24 s, even when the difference in boiling point was 4°C, as in the case of TEP and methyl salicylate. Furthermore, interfering agents - dichloromethane, ethanol, and toluene - were also included in the subsequent gaseous mixture samples. The boiling point of these six components ranged from 78°C to 219°C. All six components were clearly separated within 70 s. This study is the first to report the clear separation of gas mixtures of components with close boiling points. The column efficiency was experimentally determined to be 12,810 plates/m.

  19. Harmonization of European laboratory response networks by implementing CWA 15793: use of a gap analysis and an "insider" exercise as tools.

    PubMed

    Sundqvist, Bo; Bengtsson, Ulrika Allard; Wisselink, Henk J; Peeters, Ben P H; van Rotterdam, Bart; Kampert, Evelien; Bereczky, Sándor; Johan Olsson, N G; Szekely Björndal, Asa; Zini, Sylvie; Allix, Sébastien; Knutsson, Rickard

    2013-09-01

    Laboratory response networks (LRNs) have been established for security reasons in several countries including the Netherlands, France, and Sweden. LRNs function in these countries as a preparedness measure for a coordinated diagnostic response capability in case of a bioterrorism incident or other biocrimes. Generally, these LRNs are organized on a national level. The EU project AniBioThreat has identified the need for an integrated European LRN to strengthen preparedness against animal bioterrorism. One task of the AniBioThreat project is to suggest a plan to implement laboratory biorisk management CWA 15793:2011 (CWA 15793), a management system built on the principle of continual improvement through the Plan-Do-Check-Act (PDCA) cycle. The implementation of CWA 15793 can facilitate trust and credibility in a future European LRN and is an assurance that the work done at the laboratories is performed in a structured way with continuous improvements. As a first step, a gap analysis was performed to establish the current compliance status of biosafety and laboratory biosecurity management with CWA 15793 in 5 AniBioThreat partner institutes in France (ANSES), the Netherlands (CVI and RIVM), and Sweden (SMI and SVA). All 5 partners are national and/or international laboratory reference institutes in the field of public or animal health and possess high-containment laboratories and animal facilities. The gap analysis showed that the participating institutes already have robust biorisk management programs in place, but several gaps were identified that need to be addressed. Despite differences between the participating institutes in their compliance status, these variations are not significant. Biorisk management exercises also have been identified as a useful tool to control compliance status and thereby implementation of CWA 15793. An exercise concerning an insider threat and loss of a biological agent was performed at SVA in the AniBioThreat project to evaluate

  20. Extremely sensitive CWA analyzer based on a novel optical pressure sensor in photoacoustic gas analysis

    NASA Astrophysics Data System (ADS)

    Kauppinen, Jyrki K.; Koskinen, Vesa; Uotila, Juho; Kauppinen, Ismo K.

    2004-12-01

    Major improvement into the sensitivity of broadband Fourier transform infrared (FTIR) spectrometers, used in gas analysis, can be achieved by a photoacoustic detection system, which bases on a recently introduced optical pressure sensor. The sensor is a cantilever-type microphone with interferometric measurement of its free end displacement. By using a preliminary prototype of the photoacoustic gas detector, equipped with the proposed sensor and a black body radiation source, a detection limit in the sub-ppb range was obtained for e.g. methane gas. The limit, obtained in non-resonant operation mode, is very close to the best photoacoustic results achieved with powerfull laser sources and by exploiting the cell resonances. It is also orders of magnitude better than any measurement with a black body radiation source. Furthermore, the ultimate sensitivity leads on to very small detection limits also for several chemical warfare agents (CWA) e.g. sarin, tabun and mustard. The small size of the sensor and its great thermal stability enables the construction of an extremely sensitive portable CWA analyzer in the near future.

  1. Computational Spectrum of Agent Model Simulation

    SciTech Connect

    Perumalla, Kalyan S

    2010-01-01

    The study of human social behavioral systems is finding renewed interest in military, homeland security and other applications. Simulation is the most generally applied approach to studying complex scenarios in such systems. Here, we outline some of the important considerations that underlie the computational aspects of simulation-based study of human social systems. The fundamental imprecision underlying questions and answers in social science makes it necessary to carefully distinguish among different simulation problem classes and to identify the most pertinent set of computational dimensions associated with those classes. We identify a few such classes and present their computational implications. The focus is then shifted to the most challenging combinations in the computational spectrum, namely, large-scale entity counts at moderate to high levels of fidelity. Recent developments in furthering the state-of-the-art in these challenging cases are outlined. A case study of large-scale agent simulation is provided in simulating large numbers (millions) of social entities at real-time speeds on inexpensive hardware. Recent computational results are identified that highlight the potential of modern high-end computing platforms to push the envelope with respect to speed, scale and fidelity of social system simulations. Finally, the problem of shielding the modeler or domain expert from the complex computational aspects is discussed and a few potential solution approaches are identified.

  2. Structure-activity predictions of properties of organophosphorus pesticides and chemical agents important for optical detection. Master`s thesis

    SciTech Connect

    Porte, R.E.

    1995-12-01

    This thesis presents the results of an investigation for estimating various physicochemical properties of chemical warfare agents and organophosphorus pesticides. The determination of aqueous solubility, - octanol/water partition coefficients, and alkaline hydrolysis rate constants will be used in the development of a chemical sensor using fiber optic spectroscopy. These three parameters will effect the limit of detection for each compound by limiting the concentration in the detector. The parameters were estimated by linear free energy relationships and quantitative structure activity relationships using experimental data for compounds of similar chemical structure. The results of this thesis showed that the hydrophobic medium represented by 1-octanol did concentrate the OP pesticides but did not significantly concentrate CWA, CWA simulants, or CWA hydrolysis products. Correlations were evaluated for six classes of organophosphorus compounds. The limitation of this approach to predicting physicochemical parameters is not in the molecular descriptors used in the regression equations but in the availability of existing experimental data.

  3. FTIR gas analysis with improved sensitivity and selectivity for CWA and TIC detection

    NASA Astrophysics Data System (ADS)

    Phillips, Charles M.; Tan, Huwei

    2010-04-01

    This presentation describes the use of an FTIR (Fourier Transform Infrared)-based spectrometer designed to continuously monitor ambient air for the presence of chemical warfare agents (CWAs) and toxic industrial chemicals (TICs). The necessity of a reliable system capable of quickly and accurately detecting very low levels of CWAs and TICs while simultaneously retaining a negligible false alarm rate will be explored. Technological advancements in FTIR sensing have reduced noise while increasing selectivity and speed of detection. These novel analyzer design characteristics are discussed in detail and descriptions are provided which show how optical throughput, gas cell form factor, and detector response are optimized. The hardware and algorithms described here will explain why this FTIR system is very effective for the simultaneous detection and speciation of a wide variety of toxic compounds at ppb concentrations. Analytical test data will be reviewed demonstrating the system's sensitivity to and selectivity for specific CWAs and TICs; this will include recent data acquired as part of the DHS ARFCAM (Autonomous Rapid Facility Chemical Agent Monitor) project. These results include analyses of the data from live agent testing for the determination of CWA detection limits, immunity to interferences, detection times, residual noise analysis and false alarm rates. Sensing systems such as this are critical for effective chemical hazard identification which is directly relevant to the CBRNE community.

  4. Virtual agents in a simulated virtual training environment

    NASA Technical Reports Server (NTRS)

    Achorn, Brett; Badler, Norman L.

    1993-01-01

    A drawback to live-action training simulations is the need to gather a large group of participants in order to train a few individuals. One solution to this difficulty is the use of computer-controlled agents in a virtual training environment. This allows a human participant to be replaced by a virtual, or simulated, agent when only limited responses are needed. Each agent possesses a specified set of behaviors and is capable of limited autonomous action in response to its environment or the direction of a human trainee. The paper describes these agents in the context of a simulated hostage rescue training session, involving two human rescuers assisted by three virtual (computer-controlled) agents and opposed by three other virtual agents.

  5. Development of a persistent chemical agent simulation system

    NASA Technical Reports Server (NTRS)

    1983-01-01

    A Persistent Chemical Agent Simulation System was developed (PCASS) to simulate, for force-on-force training exercises, the field environment produced by the presence of persistent chemical agents. Such a simulant system must satisfy several requirements to be of value as a training aid. Specifically, it must provide for realistic training which will generate competency in at least the following areas: (1) detection of the persistent agent presence; (2) proper use of protective equipment and procedures; (3) determination of the extent of contamination; and (4) decontamination of equipment and personnel.

  6. 2 CFR 1532.1120 - What is the purpose of CAA or CWA disqualification?

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... and Reinstatement Under the Clean Air Act and Clean Water Act § 1532.1120 What is the purpose of CAA or CWA disqualification? As provided for in Executive Order 11738 (3 CFR, 1973 Comp., p. 799),...

  7. 2 CFR 1532.1120 - What is the purpose of CAA or CWA disqualification?

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... and Reinstatement Under the Clean Air Act and Clean Water Act § 1532.1120 What is the purpose of CAA or CWA disqualification? As provided for in Executive Order 11738 (3 CFR, 1973 Comp., p. 799),...

  8. 2 CFR 1532.1120 - What is the purpose of CAA or CWA disqualification?

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... and Reinstatement Under the Clean Air Act and Clean Water Act § 1532.1120 What is the purpose of CAA or CWA disqualification? As provided for in Executive Order 11738 (3 CFR, 1973 Comp., p. 799),...

  9. 2 CFR 1532.1120 - What is the purpose of CAA or CWA disqualification?

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... and Reinstatement Under the Clean Air Act and Clean Water Act § 1532.1120 What is the purpose of CAA or CWA disqualification? As provided for in Executive Order 11738 (3 CFR, 1973 Comp., p. 799),...

  10. A simulation-based tutor that reasons about multiple agents

    SciTech Connect

    Rhodes Eliot, C. III; Park Woolf, B.

    1996-12-31

    This paper examines the problem of modeling multiple agents within an intelligent simulation-based tutor. Multiple agent and planning technology were used to enable the system to critique a human agent`s reasoning about multiple agents. This perspective arises naturally whenever a student must learn to lead and coordinate a team of people. The system dynamically selected teaching goals, instantiated plans and modeled the student and the domain as it monitored the student`s progress. The tutor provides one of the first complete integrations of a real-time simulation with knowledge-based reasoning. Other novel techniques of the system are reported, such as common-sense reasoning about plans, reasoning about protocol mechanisms, and using a real-time simulation for training.

  11. Evaluation of the efficacy of a portable LIBS system for detection of CWA on surfaces.

    PubMed

    L'Hermite, D; Vors, E; Vercouter, T; Moutiers, G

    2016-05-01

    Laser-induced breakdown spectroscopy (LIBS) is a laser-based optical technique particularly suited for in situ surface analysis. A portable LIBS instrument was tested to detect surface chemical contamination by chemical warfare agents (CWAs). Test of detection of surface contamination was carried out in a toxlab facility with four CWAs, sarin (GB), lewisite (L1), mustard gas (HD), and VX, which were deposited on different substrates, wood, concrete, military green paint, gloves, and ceramic. The CWAs were detected by means of the detection of atomic markers (As, P, F, Cl, and S). The LIBS instrument can give a direct response in terms of detection thanks to an integrated interface for non-expert users or so called end-users. We have evaluated the capability of automatic detection of the selected CWAs. The sensitivity of our portable LIBS instrument was confirmed for the detection of a CWA at surface concentrations above 15 μg/cm(2). The simultaneous detection of two markers may lead to a decrease of the number of false positive. PMID:26906000

  12. Hydrophobic polydimethylsiloxane (PDMS) coating of mesoporous silica and its use as a preconcentrating agent of gas analytes.

    PubMed

    Park, Eun Ji; Cho, Youn Kyoung; Kim, Dae Han; Jeong, Myung-Geun; Kim, Yong Ho; Kim, Young Dok

    2014-09-01

    Mesoporous silica with mean pore size of ∼14 nm was coated by polydimethylsiloxane (PDMS) using a thermal deposition method. We showed that the inner walls of pores larger than ∼8 nm can be coated by thin layers of PDMS, and the surfaces consisting of PDMS-coated silica were superhydrophobic, with water contact angles close to 170°. We used the PDMS-coated silica as adsorbents of various gas-phase chemical warfare agent (CWA) simulants. PDMS-coated silica allowed molecular desorption of various CWA simulants even after exposure under highly humid conditions and, therefore, is applicable as an agent for the preconcentration of gas-phase analytes to enhance the sensitivities of various sensors. PMID:25102134

  13. Evolution of cooperative behavior in simulation agents

    SciTech Connect

    Stroud, P.D.

    1998-04-01

    A simulated automobile factory paint shop is used as a testbed for exploring the emulation of human decision making behavior. A discrete events simulation of the paint shop as a collection of interacting Java actors is described. An evolutionary cognitive architecture is under development for building software actors to emulate humans in simulations of human dominated complex systems. In this paper, the cognitive architecture is extended by implementing a persistent population of trial behaviors with an incremental fitness valuation update strategy, and by allowing a group of cognitive actors to share information. A proof of principle demonstration is presented.

  14. Brahms An Agent-Oriented Language for Work Practice Simulation and Multi-Agent Systems Development

    NASA Astrophysics Data System (ADS)

    Sierhuis, Maarten; Clancey, William J.; van Hoof, Ron J. J.

    Brahms is a multi-agent modeling language for simulating human work practice that emerges from work processes in organizations. The same Brahms language can be used to implement and execute distributed multi-agent systems, based on models of work practice that were first simulated. Brahms demonstrates how a multi-agent belief-desire-intention language, symbolic cognitive modeling, traditional business process modeling, activity-and situated cognition theories are brought together in a coherent approach for analysis and design of organizations and human-centered systems.

  15. A decontamination study of simulated chemical and biological agents

    NASA Astrophysics Data System (ADS)

    Uhm, Han S.; Lee, Han Y.; Hong, Yong C.; Shin, Dong H.; Park, Yun H.; Hong, Yi F.; Lee, Chong K.

    2007-07-01

    A comprehensive decontamination scheme of the chemical and biological agents, including airborne agents and surface contaminating agents, is presented. When a chemical and biological attack occurs, it is critical to decontaminate facilities or equipments to an acceptable level in a very short time. The plasma flame presented here may provide a rapid and effective elimination of toxic substances in the interior air in isolated spaces. As an example, a reaction chamber, with the dimensions of a 22cm diameter and 30cm length, purifies air with an airflow rate of 5000l/min contaminated with toluene, the simulated chemical agent, and soot from a diesel engine, the simulated aerosol for biological agents. Although the airborne agents in an isolated space are eliminated to an acceptable level by the plasma flame, the decontamination of the chemical and biological agents cannot be completed without cleaning surfaces of the facilities. A simulated sterilization study of micro-organisms was carried out using the electrolyzed ozone water. The electrolyzed ozone water very effectively kills endospores of Bacillus atrophaeus (ATCC 9372) within 3min. The electrolyzed ozone water also kills the vegetative micro-organisms, fungi, and virus. The electrolyzed ozone water, after the decontamination process, disintegrates into ordinary water and oxygen without any trace of harmful materials to the environment.

  16. A decontamination study of simulated chemical and biological agents

    SciTech Connect

    Uhm, Han S.; Lee, Han Y.; Hong, Yong C.; Shin, Dong H.; Park, Yun H.; Hong, Yi F.; Lee, Chong K.

    2007-07-01

    A comprehensive decontamination scheme of the chemical and biological agents, including airborne agents and surface contaminating agents, is presented. When a chemical and biological attack occurs, it is critical to decontaminate facilities or equipments to an acceptable level in a very short time. The plasma flame presented here may provide a rapid and effective elimination of toxic substances in the interior air in isolated spaces. As an example, a reaction chamber, with the dimensions of a 22 cm diameter and 30 cm length, purifies air with an airflow rate of 5000 l/min contaminated with toluene, the simulated chemical agent, and soot from a diesel engine, the simulated aerosol for biological agents. Although the airborne agents in an isolated space are eliminated to an acceptable level by the plasma flame, the decontamination of the chemical and biological agents cannot be completed without cleaning surfaces of the facilities. A simulated sterilization study of micro-organisms was carried out using the electrolyzed ozone water. The electrolyzed ozone water very effectively kills endospores of Bacillus atrophaeus (ATCC 9372) within 3 min. The electrolyzed ozone water also kills the vegetative micro-organisms, fungi, and virus. The electrolyzed ozone water, after the decontamination process, disintegrates into ordinary water and oxygen without any trace of harmful materials to the environment.

  17. Cognitive Modeling for Agent-Based Simulation of Child Maltreatment

    NASA Astrophysics Data System (ADS)

    Hu, Xiaolin; Puddy, Richard

    This paper extends previous work to develop cognitive modeling for agent-based simulation of child maltreatment (CM). The developed model is inspired from parental efficacy, parenting stress, and the theory of planned behavior. It provides an explanatory, process-oriented model of CM and incorporates causality relationship and feedback loops from different factors in the social ecology in order for simulating the dynamics of CM. We describe the model and present simulation results to demonstrate the features of this model.

  18. Agent-Based Simulations for Project Management

    NASA Technical Reports Server (NTRS)

    White, J. Chris; Sholtes, Robert M.

    2011-01-01

    Currently, the most common approach used in project planning tools is the Critical Path Method (CPM). While this method was a great improvement over the basic Gantt chart technique being used at the time, it now suffers from three primary flaws: (1) task duration is an input, (2) productivity impacts are not considered , and (3) management corrective actions are not included. Today, computers have exceptional computational power to handle complex simulations of task e)(eculion and project management activities (e.g ., dynamically changing the number of resources assigned to a task when it is behind schedule). Through research under a Department of Defense contract, the author and the ViaSim team have developed a project simulation tool that enables more realistic cost and schedule estimates by using a resource-based model that literally turns the current duration-based CPM approach "on its head." The approach represents a fundamental paradigm shift in estimating projects, managing schedules, and reducing risk through innovative predictive techniques.

  19. Real-time trace detection and identification of chemical warfare agent simulants using recent advances in proton transfer reaction time-of-flight mass spectrometry.

    PubMed

    Petersson, Fredrik; Sulzer, Philipp; Mayhew, Chris A; Watts, Peter; Jordan, Alfons; Märk, Lukas; Märk, Tilmann D

    2009-12-01

    This work demonstrates for the first time the potential of using recent developments in proton transfer reaction mass spectrometry for the rapid detection and identification of chemical warfare agents (CWAs) in real-time. A high-resolution (m/Deltam up to 8000) and high-sensitivity (approximately 50 cps/ppbv) proton transfer reaction time-of-flight mass spectrometer (PTR-TOF 8000 from Ionicon Analytik GmBH) has been successfully used to detect a number of CWA simulants at room temperature; namely dimethyl methylphosphonate, diethyl methylphosphonate, diisopropyl methylphosphonate, dipropylene glycol monomethyl ether and 2-chloroethyl ethyl sulfide. Importantly, we demonstrate in this paper the potential to identify CWAs with a high level of confidence in complex chemical environments, where multiple threat agents and interferents could also be present in trace amounts, thereby reducing the risk of false positives. Instantaneous detection and identification of trace quantities of chemical threats using proton transfer reaction mass spectrometry could form the basis for a timely warning system capability with greater precision and accuracy than is currently provided by existing analytical technologies. PMID:19902419

  20. Agent-Based Modeling and Simulation on Emergency Evacuation

    NASA Astrophysics Data System (ADS)

    Ren, Chuanjun; Yang, Chenghui; Jin, Shiyao

    Crowd stampedes and evacuation induced by panic caused by emergences often lead to fatalities as people are crushed, injured, trampled or even dead. Such phenomena may be triggered in life-threatening situations such as fires, explosions in crowded buildings. Emergency evacuation simulation has recently attracted the interest of a rapidly increasing number of scientists. This paper presents an Agent-Based Modeling and Simulation using Repast software to construct crowd evacuations for emergency response from an area under a fire. Various types of agents and different attributes of agents are designed in contrast to traditional modeling. The attributes that govern the characteristics of the people are studied and tested by iterative simulations. Simulations are also conducted to demonstrate the effect of various parameters of agents. Some interesting results were observed such as "faster is slower" and the ignorance of available exits. At last, simulation results suggest practical ways of minimizing the harmful consequences of such events and the existence of an optimal escape strategy.

  1. Modeling and simulating human teamwork behaviors using intelligent agents

    NASA Astrophysics Data System (ADS)

    Fan, Xiaocong; Yen, John

    2004-12-01

    Among researchers in multi-agent systems there has been growing interest in using intelligent agents to model and simulate human teamwork behaviors. Teamwork modeling is important for training humans in gaining collaborative skills, for supporting humans in making critical decisions by proactively gathering, fusing, and sharing information, and for building coherent teams with both humans and agents working effectively on intelligence-intensive problems. Teamwork modeling is also challenging because the research has spanned diverse disciplines from business management to cognitive science, human discourse, and distributed artificial intelligence. This article presents an extensive, but not exhaustive, list of work in the field, where the taxonomy is organized along two main dimensions: team social structure and social behaviors. Along the dimension of social structure, we consider agent-only teams and mixed human-agent teams. Along the dimension of social behaviors, we consider collaborative behaviors, communicative behaviors, helping behaviors, and the underpinning of effective teamwork-shared mental models. The contribution of this article is that it presents an organizational framework for analyzing a variety of teamwork simulation systems and for further studying simulated teamwork behaviors.

  2. Agent 2003 Conference on Challenges in Social Simulation

    SciTech Connect

    Margaret Clemmons, ed.

    2003-01-01

    Welcome to the Proceedings of the fourth in a series of agent simulation conferences cosponsored by Argonne National Laboratory and The University of Chicago. Agent 2003 is the second conference in which three Special Interest Groups from the North American Association for Computational Social and Organizational Science (NAACSOS) have been involved in planning the program--Computational Social Theory; Simulation Applications; and Methods, Toolkits and Techniques. The theme of Agent 2003, Challenges in Social Simulation, is especially relevant, as there seems to be no shortage of such challenges. Agent simulation has been applied with increasing frequency to social domains for several decades, and its promise is clear and increasingly visible. Like any nascent scientific methodology, however, it faces a number of problems or issues that must be addressed in order to progress. These challenges include: (1) Validating models relative to the social settings they are designed to represent; (2) Developing agents and interactions simple enough to understand but sufficiently complex to do justice to the social processes of interest; (3) Bridging the gap between empirically spare artificial societies and naturally occurring social phenomena; (4) Building multi-level models that span processes across domains; (5) Promoting a dialog among theoretical, qualitative, and empirical social scientists and area experts, on the one hand, and mathematical and computational modelers and engineers, on the other; (6) Using that dialog to facilitate substantive progress in the social sciences; and (7) Fulfilling the aspirations of users in business, government, and other application areas, while recognizing and addressing the preceding challenges. Although this list hardly exhausts the challenges the field faces, it does identify topics addressed throughout the presentations of Agent 2003. Agent 2003 is part of a much larger process in which new methods and techniques are applied to

  3. Tutorial on agent-based modeling and simulation. Part 2 : how to model with agents.

    SciTech Connect

    Macal, C. M.; North, M. J.; Decision and Information Sciences

    2006-01-01

    Agent-based modeling and simulation (ABMS) is a new approach to modeling systems comprised of interacting autonomous agents. ABMS promises to have far-reaching effects on the way that businesses use computers to support decision-making and researchers use electronic laboratories to do research. Some have gone so far as to contend that ABMS is a new way of doing science. Computational advances make possible a growing number of agent-based applications across many fields. Applications range from modeling agent behavior in the stock market and supply chains, to predicting the spread of epidemics and the threat of bio-warfare, from modeling the growth and decline of ancient civilizations to modeling the complexities of the human immune system, and many more. This tutorial describes the foundations of ABMS, identifies ABMS toolkits and development methods illustrated through a supply chain example, and provides thoughts on the appropriate contexts for ABMS versus conventional modeling techniques.

  4. Agent-based simulation of a financial market

    NASA Astrophysics Data System (ADS)

    Raberto, Marco; Cincotti, Silvano; Focardi, Sergio M.; Marchesi, Michele

    2001-10-01

    This paper introduces an agent-based artificial financial market in which heterogeneous agents trade one single asset through a realistic trading mechanism for price formation. Agents are initially endowed with a finite amount of cash and a given finite portfolio of assets. There is no money-creation process; the total available cash is conserved in time. In each period, agents make random buy and sell decisions that are constrained by available resources, subject to clustering, and dependent on the volatility of previous periods. The model proposed herein is able to reproduce the leptokurtic shape of the probability density of log price returns and the clustering of volatility. Implemented using extreme programming and object-oriented technology, the simulator is a flexible computational experimental facility that can find applications in both academic and industrial research projects.

  5. Tutorial on agent-based modeling and simulation.

    SciTech Connect

    Macal, C. M.; North, M. J.; Decision and Information Sciences

    2005-01-01

    Agent-based modeling and simulation (ABMS) is a new approach to modeling systems comprised of autonomous, interacting agents. ABMS promises to have far-reaching effects on the way that businesses use computers to support decision-making and researchers use electronic laboratories to support their research. Some have gone so far as to contend that ABMS is a third way of doing science besides deductive and inductive reasoning. Computational advances have made possible a growing number of agent-based applications in a variety of fields. Applications range from modeling agent behavior in the stock market and supply chains, to predicting the spread of epidemics and the threat of bio-warfare, from modeling consumer behavior to understanding the fall of ancient civilizations, to name a few. This tutorial describes the theoretical and practical foundations of ABMS, identifies toolkits and methods for developing ABMS models, and provides some thoughts on the relationship between ABMS and traditional modeling techniques.

  6. Simulation of convoy of unmanned vehicles using agent based modeling

    NASA Astrophysics Data System (ADS)

    Sharma, Sharad; Singh, Harpreet; Gerhart, G. R.

    2007-10-01

    There has been an increasing interest of unmanned vehicles keeping the importance of defense and security. A few models for a convoy of unmanned vehicle exist in literature. The objective of this paper is to exploit agent based modeling technique for a convoy of unmanned vehicles where each vehicle is an agent. Using this approach, the convoy of vehicles reaches a specified goal from a starting point. Each agent is associated with number of sensors. The agents make intelligent decisions based on sensor inputs and at the same time maintaining their group capability and behavior. The simulation is done for a battlefield environment from a single starting point to a single goal. This approach can be extended for multiple starting points to reach multiple goals. The simulation gives the time taken by the convoy to reach a goal from its initial position. In the battlefield environment, commanders make various tactical decisions depending upon the location of an enemy outpost, minefields, number of soldiers in platoons, and barriers. The simulation can help the commander to make effective decisions depending on battlefield, convoy and obstacles to reach a particular goal. The paper describes the proposed approach and gives the simulation results. The paper also gives problems for future research in this area.

  7. THE APPLICATION OF SINGLE PARTICLE AEROSOL MASS SPECTROMETRY FOR THE DETECTION AND IDENTIFICATION OF HIGH EXPLOSIVES AND CHEMICAL WARFARE AGENTS

    SciTech Connect

    Martin, A

    2006-10-23

    Single Particle Aerosol Mass Spectrometry (SPAMS) was evaluated as a real-time detection technique for single particles of high explosives. Dual-polarity time-of-flight mass spectra were obtained for samples of 2,4,6-trinitrotoluene (TNT), 1,3,5-trinitro-1,3,5-triazinane (RDX), and pentaerythritol tetranitrate (PETN); peaks indicative of each compound were identified. Composite explosives, Comp B, Semtex 1A, and Semtex 1H were also analyzed, and peaks due to the explosive components of each sample were present in each spectrum. Mass spectral variability with laser fluence is discussed. The ability of the SPAMS system to identify explosive components in a single complex explosive particle ({approx}1 pg) without the need for consumables is demonstrated. SPAMS was also applied to the detection of Chemical Warfare Agent (CWA) simulants in the liquid and vapor phases. Liquid simulants for sarin, cyclosarin, tabun, and VX were analyzed; peaks indicative of each simulant were identified. Vapor phase CWA simulants were adsorbed onto alumina, silica, Zeolite, activated carbon, and metal powders which were directly analyzed using SPAMS. The use of metal powders as adsorbent materials was especially useful in the analysis of triethyl phosphate (TEP), a VX stimulant, which was undetectable using SPAMS in the liquid phase. The capability of SPAMS to detect high explosives and CWA simulants using one set of operational conditions is established.

  8. Agent-based modeling and simulation Part 3 : desktop ABMS.

    SciTech Connect

    Macal, C. M.; North, M. J.; Decision and Information Sciences

    2007-01-01

    Agent-based modeling and simulation (ABMS) is a new approach to modeling systems comprised of autonomous, interacting agents. ABMS promises to have far-reaching effects on the way that businesses use computers to support decision-making and researchers use electronic laboratories to support their research. Some have gone so far as to contend that ABMS 'is a third way of doing science,' in addition to traditional deductive and inductive reasoning (Axelrod 1997b). Computational advances have made possible a growing number of agent-based models across a variety of application domains. Applications range from modeling agent behavior in the stock market, supply chains, and consumer markets, to predicting the spread of epidemics, the threat of bio-warfare, and the factors responsible for the fall of ancient civilizations. This tutorial describes the theoretical and practical foundations of ABMS, identifies toolkits and methods for developing agent models, and illustrates the development of a simple agent-based model of shopper behavior using spreadsheets.

  9. Greening the CWA consent decree - some examples of collaborative research amongst USEPA and municipalities

    EPA Science Inventory

    Combined sewer overflows (CSOs) violate the Clean Water Act Enforcement of CWA boils down to settlements with US cities – typically billions of dollars Green Infrastructure (GI) has come into view as part of consent decree settlements These settlements are a primary way to rehab...

  10. Computational Investigations of Potential Energy Function Development for Metal--Organic Framework Simulations, Metal Carbenes, and Chemical Warfare Agents

    NASA Astrophysics Data System (ADS)

    Cioce, Christian R.

    sigma donates, and subsequent back-bonding occurs into a pi* antibonding orbital. This is a different type of interaction not seen in the three existing classes of metal-carbene complexes, namely Fischer, Schrock, and Grubbs. Finally, the virtual engineering of enhanced chemical warfare agent (CWA) detection systems is discussed. As part of a U.S. Department of Defense supported research project, in silico chemical modifications to a previously synthesized zinc-porphyrin, ZnCS1, were made to attempt to achieve preferential binding of the nerve agent sarin versus its simulant, DIMP (diisopropyl methylphosphonate). Upon modification, a combination of steric effects and induced hydrogen bonding allowed for the selective binding of sarin. The success of this work demonstrates the role that high performance computing can play in national security research, without the associated costs and high security required for experimentation.

  11. Multi-Agent Flight Simulation with Robust Situation Generation

    NASA Technical Reports Server (NTRS)

    Johnson, Eric N.; Hansman, R. John, Jr.

    1994-01-01

    A robust situation generation architecture has been developed that generates multi-agent situations for human subjects. An implementation of this architecture was developed to support flight simulation tests of air transport cockpit systems. This system maneuvers pseudo-aircraft relative to the human subject's aircraft, generating specific situations for the subject to respond to. These pseudo-aircraft maneuver within reasonable performance constraints, interact in a realistic manner, and make pre-recorded voice radio communications. Use of this system minimizes the need for human experimenters to control the pseudo-agents and provides consistent interactions between the subject and the pseudo-agents. The achieved robustness of this system to typical variations in the subject's flight path was explored. It was found to successfully generate specific situations within the performance limitations of the subject-aircraft, pseudo-aircraft, and the script used.

  12. Development of a Persistent Chemical Agent Simulator System (PCASS)

    NASA Technical Reports Server (NTRS)

    Mcginness, W. G.

    1983-01-01

    The development of a persistent chemical agent simulation system (PCASS) is described. This PCASS is to be used for the military training of troops to simulate actual chemical warfare. The purpose of this system is to facilitate in the determination of chemical contamination and effectiveness of decontamination for training purposes. The fluorescent tracer employed has no daylight activation, but yet is easily removed with a decontaminate solution or water and surfactants. Also employed is a time delayed color developing system. When an individual is subjected to the PCASS and does not decontaminate adequately, red blotches or red coloration will develop as a function of time and temperature. The intent of this is to simulate the delayed chemical reaction of mustard contaminates.

  13. Task-level object grasping for simulated agents.

    PubMed

    Douville, B; Levison, L; Badler, N I

    1996-01-01

    Simulating a human figure performing a manual task requires that the agent interact with objects in the environment in a realistic manner. Graphic or programming interfaces to control human figure animation, however, do not allow the animator to instruct the system with concise "high-level" commands. Instructions coming from a high-level planner cannot be directly given to a synthetic agent because they do not specify such details as which end-effector to use or where on the object to grasp. Because current animation systems require joint angle displacement descriptions of motion--even for motions that incorporate upwards of 15 joints--an efficient connection between high-level specifications and low-level hand joint motion is required. In this paper we describe a system that directs task-level, general-purpose, object grasping for a simulated human agent. The Object-Specific Reasoner (OSR) is a reasoning module that uses knowledge of the object of the underspecified action to generate values for missing parameters. The Grasp Behavior manages simultaneous motions of the joints in the hand, wrist, and arm, and provides a programmer with a high-level description of the desired action. When composed hierarchically, the OSR and the Grasp behavior interpret task-level commands and direct specific motions to the animation system. These modules are implemented as part of the Jack system at the University of Pennsylvania. PMID:11539378

  14. Hair analysis as a useful procedure for detection of vapour exposure to chemical warfare agents: simulation of sulphur mustard with methyl salicylate.

    PubMed

    Spiandore, Marie; Piram, Anne; Lacoste, Alexandre; Josse, Denis; Doumenq, Pierre

    2014-06-01

    Chemical warfare agents (CWA) are highly toxic compounds which have been produced to kill or hurt people during conflicts or terrorist attacks. Despite the fact that their use is strictly prohibited according to international convention, populations' exposure still recently occurred. Development of markers of exposure to CWA is necessary to distinguish exposed victims from unexposed ones. We present the first study of hair usage as passive sampler to assess contamination by chemicals in vapour form. This work presents more particularly the hair adsorption capacity for methyl salicylate used as a surrogate of the vesicant sulphur mustard. Chemical vapours toxicity through the respiratory route has historically been defined through Haber's law's concentration-time (Ct) product, and vapour exposure of hair to methyl salicylate was conducted with various times or doses of exposure in the range of incapacitating and lethal Ct products corresponding to sulphur mustard. Following exposure, extraction of methyl salicylate from hair was conducted by simple soaking in dichloromethane. Methyl salicylate could be detected on hair for vapour concentration corresponding to about one fifth of the sulphur mustard concentration that would kill 50% of exposed individuals (LCt50). The amount of methyl salicylate recovered from hair increased with time or dose of exposure. It showed a good correlation with the concentration-time product, suggesting that hair could be used like a passive sampler to assess vapour exposure to chemical compounds. It introduces great perspectives concerning the use of hair as a marker of exposure to CWA. PMID:24817050

  15. Flexible carbon nanotube sensors for nerve agent simulants

    NASA Astrophysics Data System (ADS)

    Cattanach, Kyle; Kulkarni, Rashmi D.; Kozlov, Mikhail; Manohar, Sanjeev K.

    2006-08-01

    Chemiresistor-based vapour sensors made from network films of single-walled carbon nanotube (SWNT) bundles on flexible plastic substrates (polyethylene terephthalate, PET) can be used to detect chemical warfare agent simulants for the nerve agents Sarin (diisopropyl methylphosphonate, DIMP) and Soman (dimethyl methylphosphonate, DMMP). Large, reproducible resistance changes (75-150%), are observed upon exposure to DIMP or DMMP vapours, and concentrations as low as 25 ppm can be detected. Robust sensor response to simulant vapours is observed even in the presence of large equilibrium concentrations of interferent vapours commonly found in battle-space environments, such as hexane, xylene and water (10 000 ppm each), suggesting that both DIMP and DMMP vapours are capable of selectively displacing other vapours from the walls of the SWNTs. Response to these interferent vapours can be effectively filtered out by using a 2 µm thick barrier film of the chemoselective polymer polyisobutylene (PIB) on the SWNT surface. These network films are composed of a 1-2 µm thick non-woven mesh of SWNT bundles (15-30 nm diameter), whose sensor response is qualitatively and quantitatively different from previous studies on individual SWNTs, or a network of individual SWNTs, suggesting that vapour sorption at interbundle sites could be playing an important role. This study also shows that the line patterning method used in device fabrication to obtain any desired pattern of films of SWNTs on flexible substrates can be used to rapidly screen simulants at high concentrations before developing more complicated sensor systems.

  16. Supercritical fluid extraction of chemical warfare agent simulants from soil.

    PubMed

    Griest, W H; Ramsey, R S; Ho, C H; Caldwell, W M

    1992-05-29

    Chemical warfare agent simulants are efficiently recovered from 2-ppm spikes in 1 g of Rocky Mountain Arsenal Standard Soil using methanol-carbon dioxide (5:95) at 300 atm for 2 min at 60 degrees C. Recoveries (n = 3) were 79 +/- 23% for dimethylmethylphosphonate, 93 +/- 14% for 2-chloroethylethyl sulfide, 92 +/- 13% for diisopropylfluorophosphate and 95 +/- 17% for diisopropylmethylphosphonate. Recoveries are higher than, but less precise than those achieved from a 5-min ultrasonic micro-scale extraction using methanol. Much less laboratory waste is generated than the current standard organic solvent extraction method (33 g of soil shaken with 100 ml of chloroform). PMID:1400849

  17. Validation techniques of agent based modelling for geospatial simulations

    NASA Astrophysics Data System (ADS)

    Darvishi, M.; Ahmadi, G.

    2014-10-01

    One of the most interesting aspects of modelling and simulation study is to describe the real world phenomena that have specific properties; especially those that are in large scales and have dynamic and complex behaviours. Studying these phenomena in the laboratory is costly and in most cases it is impossible. Therefore, Miniaturization of world phenomena in the framework of a model in order to simulate the real phenomena is a reasonable and scientific approach to understand the world. Agent-based modelling and simulation (ABMS) is a new modelling method comprising of multiple interacting agent. They have been used in the different areas; for instance, geographic information system (GIS), biology, economics, social science and computer science. The emergence of ABM toolkits in GIS software libraries (e.g. ESRI's ArcGIS, OpenMap, GeoTools, etc) for geospatial modelling is an indication of the growing interest of users to use of special capabilities of ABMS. Since ABMS is inherently similar to human cognition, therefore it could be built easily and applicable to wide range applications than a traditional simulation. But a key challenge about ABMS is difficulty in their validation and verification. Because of frequent emergence patterns, strong dynamics in the system and the complex nature of ABMS, it is hard to validate and verify ABMS by conventional validation methods. Therefore, attempt to find appropriate validation techniques for ABM seems to be necessary. In this paper, after reviewing on Principles and Concepts of ABM for and its applications, the validation techniques and challenges of ABM validation are discussed.

  18. Flexible carbon nanotube sensors for nerve agent simulants.

    PubMed

    Cattanach, Kyle; Kulkarni, Rashmi D; Kozlov, Mikhail; Manohar, Sanjeev K

    2006-08-28

    Chemiresistor-based vapour sensors made from network films of single-walled carbon nanotube (SWNT) bundles on flexible plastic substrates (polyethylene terephthalate, PET) can be used to detect chemical warfare agent simulants for the nerve agents Sarin (diisopropyl methylphosphonate, DIMP) and Soman (dimethyl methylphosphonate, DMMP). Large, reproducible resistance changes (75-150%), are observed upon exposure to DIMP or DMMP vapours, and concentrations as low as 25 ppm can be detected. Robust sensor response to simulant vapours is observed even in the presence of large equilibrium concentrations of interferent vapours commonly found in battle-space environments, such as hexane, xylene and water (10 000 ppm each), suggesting that both DIMP and DMMP vapours are capable of selectively displacing other vapours from the walls of the SWNTs. Response to these interferent vapours can be effectively filtered out by using a 2 µm thick barrier film of the chemoselective polymer polyisobutylene (PIB) on the SWNT surface. These network films are composed of a 1-2 µm thick non-woven mesh of SWNT bundles (15-30 nm diameter), whose sensor response is qualitatively and quantitatively different from previous studies on individual SWNTs, or a network of individual SWNTs, suggesting that vapour sorption at interbundle sites could be playing an important role. This study also shows that the line patterning method used in device fabrication to obtain any desired pattern of films of SWNTs on flexible substrates can be used to rapidly screen simulants at high concentrations before developing more complicated sensor systems. PMID:21727548

  19. Using metal complex ion-molecule reactions in a miniature rectilinear ion trap mass spectrometer to detect chemical warfare agents.

    PubMed

    Graichen, Adam M; Vachet, Richard W

    2013-06-01

    The gas-phase reactions of a series of coordinatively unsaturated [Ni(L)n](y+) complexes, where L is a nitrogen-containing ligand, with chemical warfare agent (CWA) simulants in a miniature rectilinear ion trap mass spectrometer were investigated as part of a new approach to detect CWAs. Results show that upon entering the vacuum system via a poly(dimethylsiloxane) (PDMS) membrane introduction, low concentrations of several CWA simulants, including dipropyl sulfide (simulant for mustard gas), acetonitrile (simulant for the nerve agent tabun), and diethyl phosphite (simulant for nerve agents sarin, soman, tabun, and VX), can react with metal complex ions generated by electrospray ionization (ESI), thereby providing a sensitive means of detecting these compounds. The [Ni(L)n](2+) complexes are found to be particularly reactive with the simulants of mustard gas and tabun, allowing their detection at low parts-per-billion (ppb) levels. These detection limits are well below reported exposure limits for these CWAs, which indicates the applicability of this new approach, and are about two orders of magnitude lower than electron ionization detection limits on the same mass spectrometer. The use of coordinatively unsaturated metal complexes as reagent ions offers the possibility of further tuning the ion-molecule chemistry so that desired compounds can be detected selectively or at even lower concentrations. PMID:23532782

  20. Using Metal Complex Ion-Molecule Reactions in a Miniature Rectilinear Ion Trap Mass Spectrometer to Detect Chemical Warfare Agents

    NASA Astrophysics Data System (ADS)

    Graichen, Adam M.; Vachet, Richard W.

    2013-06-01

    The gas-phase reactions of a series of coordinatively unsaturated [Ni(L)n]y+ complexes, where L is a nitrogen-containing ligand, with chemical warfare agent (CWA) simulants in a miniature rectilinear ion trap mass spectrometer were investigated as part of a new approach to detect CWAs. Results show that upon entering the vacuum system via a poly(dimethylsiloxane) (PDMS) membrane introduction, low concentrations of several CWA simulants, including dipropyl sulfide (simulant for mustard gas), acetonitrile (simulant for the nerve agent tabun), and diethyl phosphite (simulant for nerve agents sarin, soman, tabun, and VX), can react with metal complex ions generated by electrospray ionization (ESI), thereby providing a sensitive means of detecting these compounds. The [Ni(L)n]2+ complexes are found to be particularly reactive with the simulants of mustard gas and tabun, allowing their detection at low parts-per-billion (ppb) levels. These detection limits are well below reported exposure limits for these CWAs, which indicates the applicability of this new approach, and are about two orders of magnitude lower than electron ionization detection limits on the same mass spectrometer. The use of coordinatively unsaturated metal complexes as reagent ions offers the possibility of further tuning the ion-molecule chemistry so that desired compounds can be detected selectively or at even lower concentrations.

  1. Chemical Warfare Agent Degradation and Decontamination

    SciTech Connect

    Talmage, Sylvia Smith; Watson, Annetta Paule; Hauschild, Veronique; Munro, Nancy B; King, J.

    2007-02-01

    The decontamination of chemical warfare agents (CWA) from structures, environmental media, and even personnel has become an area of particular interest in recent years due to increased homeland security concerns. In addition to terrorist attacks, scenarios such as accidental releases of CWA from U.S. stockpile sites or from historic, buried munitions are also subjects for response planning. To facilitate rapid identification of practical and effective decontamination approaches, this paper reviews pathways of CWA degradation by natural means as well as those resulting from deliberately applied solutions and technologies; these pathways and technologies are compared and contrasted. We then review various technologies, both traditional and recent, with some emphasis on decontamination materials used for surfaces that are difficult to clean. Discussion is limited to the major threat CWA, namely sulfur mustard (HD, bis(2-chloroethyl)sulfide), VX (O-ethyl S-(2-diisopropylaminoethyl) methylphosphonothioate), and the G-series nerve agents. The principal G-agents are GA (tabun, ethyl N,N-dimethylphosphoramidocyanidate), GB (sarin, isopropyl methylphosphonofluoridate), and GD (soman, pinacolyl methylphosphonofluoridate). The chemical decontamination pathways of each agent are outlined, with some discussion of intermediate and final degradation product toxicity. In all cases, and regardless of the CWA degradation pathway chosen for decontamination, it will be necessary to collect and analyze pertinent environmental samples during the treatment phase to confirm attainment of clearance levels.

  2. Agent-based modeling to simulate the dengue spread

    NASA Astrophysics Data System (ADS)

    Deng, Chengbin; Tao, Haiyan; Ye, Zhiwei

    2008-10-01

    In this paper, we introduce a novel method ABM in simulating the unique process for the dengue spread. Dengue is an acute infectious disease with a long history of over 200 years. Unlike the diseases that can be transmitted directly from person to person, dengue spreads through a must vector of mosquitoes. There is still no any special effective medicine and vaccine for dengue up till now. The best way to prevent dengue spread is to take precautions beforehand. Thus, it is crucial to detect and study the dynamic process of dengue spread that closely relates to human-environment interactions where Agent-Based Modeling (ABM) effectively works. The model attempts to simulate the dengue spread in a more realistic way in the bottom-up way, and to overcome the limitation of ABM, namely overlooking the influence of geographic and environmental factors. Considering the influence of environment, Aedes aegypti ecology and other epidemiological characteristics of dengue spread, ABM can be regarded as a useful way to simulate the whole process so as to disclose the essence of the evolution of dengue spread.

  3. Using Agent Based Modeling (ABM) to Develop Cultural Interaction Simulations

    NASA Technical Reports Server (NTRS)

    Drucker, Nick; Jones, Phillip N.

    2012-01-01

    Today, most cultural training is based on or built around "cultural engagements" or discrete interactions between the individual learner and one or more cultural "others". Often, success in the engagement is the end or the objective. In reality, these interactions usually involve secondary and tertiary effects with potentially wide ranging consequences. The concern is that learning culture within a strict engagement context might lead to "checklist" cultural thinking that will not empower learners to understand the full consequence of their actions. We propose the use of agent based modeling (ABM) to collect, store, and, simulating the effects of social networks, promulgate engagement effects over time, distance, and consequence. The ABM development allows for rapid modification to re-create any number of population types, extending the applicability of the model to any requirement for social modeling.

  4. Agent-based modeling: Methods and techniques for simulating human systems

    PubMed Central

    Bonabeau, Eric

    2002-01-01

    Agent-based modeling is a powerful simulation modeling technique that has seen a number of applications in the last few years, including applications to real-world business problems. After the basic principles of agent-based simulation are briefly introduced, its four areas of application are discussed by using real-world applications: flow simulation, organizational simulation, market simulation, and diffusion simulation. For each category, one or several business applications are described and analyzed. PMID:12011407

  5. Pedestrian simulation and distribution in urban space based on visibility analysis and agent simulation

    NASA Astrophysics Data System (ADS)

    Ying, Shen; Li, Lin; Gao, Yurong

    2009-10-01

    Spatial visibility analysis is the important direction of pedestrian behaviors because our visual conception in space is the straight method to get environment information and navigate your actions. Based on the agent modeling and up-tobottom method, the paper develop the framework about the analysis of the pedestrian flow depended on visibility. We use viewshed in visibility analysis and impose the parameters on agent simulation to direct their motion in urban space. We analyze the pedestrian behaviors in micro-scale and macro-scale of urban open space. The individual agent use visual affordance to determine his direction of motion in micro-scale urban street on district. And we compare the distribution of pedestrian flow with configuration in macro-scale urban environment, and mine the relationship between the pedestrian flow and distribution of urban facilities and urban function. The paper first computes the visibility situations at the vantage point in urban open space, such as street network, quantify the visibility parameters. The multiple agents use visibility parameters to decide their direction of motion, and finally pedestrian flow reach to a stable state in urban environment through the simulation of multiple agent system. The paper compare the morphology of visibility parameters and pedestrian distribution with urban function and facilities layout to confirm the consistence between them, which can be used to make decision support in urban design.

  6. Detection of chemical warfare simulants using Raman excitation at 1064 nm

    NASA Astrophysics Data System (ADS)

    Dentinger, Claire; Mabry, Mark W.; Roy, Eric G.

    2014-05-01

    Raman spectroscopy is a powerful technique for material identification. The technique is sensitive to primary and higher ordered molecular structure and can be used to identify unknown materials by comparison with spectral reference libraries. Additionally, miniaturization of opto-electronic components has permitted development of portable Raman analyzers that are field deployable. Raman scattering is a relatively weak effect compared to a competing phenomenon, fluorescence. Even a moderate amount of fluorescence background interference can easily prevent identification of unknown materials. A long wavelength Raman system is less likely to induce fluorescence from a wider variety of materials than a higher energy visible laser system. Compounds such as methyl salicylate (MS), diethyl malonate (DEM), and dimethyl methylphosphonate (DMMP) are used as chemical warfare agent (CWA) simulants for development of analytical detection strategies. Field detection of these simulants however poses unique challenges because threat identification must be made quickly without the turnaround time usually required for a laboratory based analysis. Fortunately, these CWA simulants are good Raman scatterers, and field based detection using portable Raman instruments is promising. Measurements of the CWA simulants were done using a 1064 nm based portable Raman spectrometer. The longer wavelength excitation laser was chosen relative to a visible based laser systems because the 1064 nm based spectrometer is less likely to induce fluorescence and more suitable to a wider range of materials. To more closely mimic real world measurement situations, different sample presentations were investigated.

  7. Patient-centered appointment scheduling using agent-based simulation.

    PubMed

    Turkcan, Ayten; Toscos, Tammy; Doebbeling, Brad N

    2014-01-01

    Enhanced access and continuity are key components of patient-centered care. Existing studies show that several interventions such as providing same day appointments, walk-in services, after-hours care, and group appointments, have been used to redesign the healthcare systems for improved access to primary care. However, an intervention focusing on a single component of care delivery (i.e. improving access to acute care) might have a negative impact other components of the system (i.e. reduced continuity of care for chronic patients). Therefore, primary care clinics should consider implementing multiple interventions tailored for their patient population needs. We collected rapid ethnography and observations to better understand clinic workflow and key constraints. We then developed an agent-based simulation model that includes all access modalities (appointments, walk-ins, and after-hours access), incorporate resources and key constraints and determine the best appointment scheduling method that improves access and continuity of care. This paper demonstrates the value of simulation models to test a variety of alternative strategies to improve access to care through scheduling. PMID:25954423

  8. When Do We Simulate Non-Human Agents? Dissociating Communicative and Non-Communicative Actions

    ERIC Educational Resources Information Center

    Liepelt, Roman; Prinz, Wolfgang; Brass, Marcel

    2010-01-01

    There is strong evidence that we automatically simulate observed behavior in our motor system. Previous research suggests that this simulation process depends on whether we observe a human or a non-human agent. Measuring a motor priming effect, this study investigated the question of whether agent-sensitivity of motor simulation depends on the…

  9. Agent-Based Crowd Simulation Considering Emotion Contagion for Emergency Evacuation Problem

    NASA Astrophysics Data System (ADS)

    Faroqi, H.; Mesgari, M.-S.

    2015-12-01

    During emergencies, emotions greatly affect human behaviour. For more realistic multi-agent systems in simulations of emergency evacuations, it is important to incorporate emotions and their effects on the agents. In few words, emotional contagion is a process in which a person or group influences the emotions or behavior of another person or group through the conscious or unconscious induction of emotion states and behavioral attitudes. In this study, we simulate an emergency situation in an open square area with three exits considering Adults and Children agents with different behavior. Also, Security agents are considered in order to guide Adults and Children for finding the exits and be calm. Six levels of emotion levels are considered for each agent in different scenarios and situations. The agent-based simulated model initialize with the random scattering of agent populations and then when an alarm occurs, each agent react to the situation based on its and neighbors current circumstances. The main goal of each agent is firstly to find the exit, and then help other agents to find their ways. Numbers of exited agents along with their emotion levels and damaged agents are compared in different scenarios with different initialization in order to evaluate the achieved results of the simulated model. NetLogo 5.2 is used as the multi-agent simulation framework with R language as the developing language.

  10. Agent-Based Knowledge Discovery for Modeling and Simulation

    SciTech Connect

    Haack, Jereme N.; Cowell, Andrew J.; Marshall, Eric J.; Fligg, Alan K.; Gregory, Michelle L.; McGrath, Liam R.

    2009-09-15

    This paper describes an approach to using agent technology to extend the automated discovery mechanism of the Knowledge Encapsulation Framework (KEF). KEF is a suite of tools to enable the linking of knowledge inputs (relevant, domain-specific evidence) to modeling and simulation projects, as well as other domains that require an effective collaborative workspace for knowledge-based tasks. This framework can be used to capture evidence (e.g., trusted material such as journal articles and government reports), discover new evidence (covering both trusted and social media), enable discussions surrounding domain-specific topics and provide automatically generated semantic annotations for improved corpus investigation. The current KEF implementation is presented within a semantic wiki environment, providing a simple but powerful collaborative space for team members to review, annotate, discuss and align evidence with their modeling frameworks. The novelty in this approach lies in the combination of automatically tagged and user-vetted resources, which increases user trust in the environment, leading to ease of adoption for the collaborative environment.

  11. A Systematic Review of Agent-Based Modelling and Simulation Applications in the Higher Education Domain

    ERIC Educational Resources Information Center

    Gu, X.; Blackmore, K. L.

    2015-01-01

    This paper presents the results of a systematic review of agent-based modelling and simulation (ABMS) applications in the higher education (HE) domain. Agent-based modelling is a "bottom-up" modelling paradigm in which system-level behaviour (macro) is modelled through the behaviour of individual local-level agent interactions (micro).…

  12. Serious games experiment toward agent-based simulation

    USGS Publications Warehouse

    Wein, Anne; Labiosa, William

    2013-01-01

    We evaluate the potential for serious games to be used as a scientifically based decision-support product that supports the United States Geological Survey’s (USGS) mission--to provide integrated, unbiased scientific information that can make a substantial contribution to societal well-being for a wide variety of complex environmental challenges. Serious or pedagogical games are an engaging way to educate decisionmakers and stakeholders about environmental challenges that are usefully informed by natural and social scientific information and knowledge and can be designed to promote interactive learning and exploration in the face of large uncertainties, divergent values, and complex situations. We developed two serious games that use challenging environmental-planning issues to demonstrate and investigate the potential contributions of serious games to inform regional-planning decisions. Delta Skelta is a game emulating long-term integrated environmental planning in the Sacramento-San Joaquin Delta, California, that incorporates natural hazards (flooding and earthquakes) and consequences for California water supplies amidst conflicting water interests. Age of Ecology is a game that simulates interactions between economic and ecologic processes, as well as natural hazards while implementing agent-based modeling. The content of these games spans the USGS science mission areas related to water, ecosystems, natural hazards, land use, and climate change. We describe the games, reflect on design and informational aspects, and comment on their potential usefulness. During the process of developing these games, we identified various design trade-offs involving factual information, strategic thinking, game-winning criteria, elements of fun, number and type of players, time horizon, and uncertainty. We evaluate the two games in terms of accomplishments and limitations. Overall, we demonstrated the potential for these games to usefully represent scientific information

  13. Novel reversible and selective nerve agent simulant detection in conjunction with superoxide "turn-on" probing.

    PubMed

    Jang, Yoon Jeong; Murale, Dhiraj P; Churchill, David G

    2014-04-01

    Herein, we present fluorescein as a reversible fluorescent sensor for nerve agent simulants diethylchlorophosphate (DCP), diethyl methylphosphonate (DEMP), and diethyl cyanophosphonate (DECP). The superoxide allows for an "off-on" mechanism to regenerate fluorescein. The order of decrease in fluorescence intensity for nerve agent simulants is DCP > DEMP ≫ DECP. PMID:24558644

  14. Identifying Evacuees' Demand of Tsunami Shelters using Agent Based Simulation

    NASA Astrophysics Data System (ADS)

    Mas, E.; Adriano, B.; Koshimura, S.; Imamura, F.; Kuroiwa, J.; Yamazaki, F.; Zavala, C.; Estrada, M.

    2012-12-01

    Amongst the lessons learned in tsunami events such as the 2004 Indian Ocean and 2011 Great Tohoku Japan earthquake is that sometimes nature exceeds structural countermeasures like seawalls, breakwaters or tsunami gates. In such situations it is a challenging task for people in plain areas to find sheltering places. The vertical evacuation to multistory buildings is one alternative to provide areas for sheltering in a complex environment of evacuation. However, if the spatial distribution and the available capacity of these structures are not well displayed, conditions of evacuee over-demand or under-demand might be observed in several structures. In this study, we present the integration of the tsunami numerical modeling and the agent based simulation of evacuation as the method to estimate the sheltering demand of evacuees in an emergent behavior approach. The case study is set in La Punta district in Peru. Here, we used in the tsunami simulation a seismic source of slip distribution model (Pulido et.al. ,2011; Chlieh et.al, 2011) for a possible future tsunami scenario in the central Andes. We modeled three alternatives of evacuation. First, the horizontal evacuation scenario was analyzed to support the necessity of the sheltering-in-place option for the district. Second, the vertical evacuation scenario and third, the combination of vertical and horizontal evacuation scenarios of pedestrians and vehicles were conducted. In the last two alternatives, the demand of evacuees were measured at each official tsunami evacuation building and compared to the sheltering capacity of the structure. Results showed that out of twenty tsunami evacuation buildings, thirteen resulted with over-demands and seven were still with available space. Also it is confirmed that in this case the horizontal evacuation might lead to a high number of casualties due to the traffic congestion at the neck of the district. Finally the vertical evacuation would be a suitable solution for this area

  15. 2 CFR 1532.1110 - How will a CAA or CWA conviction affect my eligibility to participate in Federal contracts...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... the Clean Air Act and Clean Water Act § 1532.1110 How will a CAA or CWA conviction affect my... debarment and suspension system (i.e. covered transactions under subpart A through I of 2 CFR part 180, or prohibited awards under 48 CFR part 9, subpart 9.4), if you: (a) Will perform any part of the transaction...

  16. 2 CFR 1532.1110 - How will a CAA or CWA conviction affect my eligibility to participate in Federal contracts...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... the Clean Air Act and Clean Water Act § 1532.1110 How will a CAA or CWA conviction affect my... debarment and suspension system (i.e. covered transactions under subpart A through I of 2 CFR part 180, or prohibited awards under 48 CFR part 9, subpart 9.4), if you: (a) Will perform any part of the transaction...

  17. 2 CFR 1532.1110 - How will a CAA or CWA conviction affect my eligibility to participate in Federal contracts...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... the Clean Air Act and Clean Water Act § 1532.1110 How will a CAA or CWA conviction affect my... debarment and suspension system (i.e. covered transactions under subpart A through I of 2 CFR part 180, or prohibited awards under 48 CFR part 9, subpart 9.4), if you: (a) Will perform any part of the transaction...

  18. 2 CFR 1532.1130 - How does disqualification under the CAA or CWA differ from a Federal discretionary suspension or...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Clean Air Act and Clean Water Act § 1532.1130 How does disqualification under the CAA or CWA differ from... 2 CFR part 180 or under 48 CFR part 9, subpart 9.4, are exclusions imposed at the discretion of... I of 2 CFR part 180, or under 48 CFR part 9, subpart 9.4....

  19. 2 CFR 1532.1130 - How does disqualification under the CAA or CWA differ from a Federal discretionary suspension or...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Clean Air Act and Clean Water Act § 1532.1130 How does disqualification under the CAA or CWA differ from... 2 CFR part 180 or under 48 CFR part 9, subpart 9.4, are exclusions imposed at the discretion of... I of 2 CFR part 180, or under 48 CFR part 9, subpart 9.4....

  20. 2 CFR 1532.1110 - How will a CAA or CWA conviction affect my eligibility to participate in Federal contracts...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... the Clean Air Act and Clean Water Act § 1532.1110 How will a CAA or CWA conviction affect my... debarment and suspension system (i.e. covered transactions under subpart A through I of 2 CFR part 180, or prohibited awards under 48 CFR part 9, subpart 9.4), if you: (a) Will perform any part of the transaction...

  1. 2 CFR 1532.1130 - How does disqualification under the CAA or CWA differ from a Federal discretionary suspension or...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Clean Air Act and Clean Water Act § 1532.1130 How does disqualification under the CAA or CWA differ from... 2 CFR part 180 or under 48 CFR part 9, subpart 9.4, are exclusions imposed at the discretion of... I of 2 CFR part 180, or under 48 CFR part 9, subpart 9.4....

  2. 2 CFR 1532.1130 - How does disqualification under the CAA or CWA differ from a Federal discretionary suspension or...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Clean Air Act and Clean Water Act § 1532.1130 How does disqualification under the CAA or CWA differ from... 2 CFR part 180 or under 48 CFR part 9, subpart 9.4, are exclusions imposed at the discretion of... I of 2 CFR part 180, or under 48 CFR part 9, subpart 9.4....

  3. Surface studies of aminoferrocene derivatives on gold: electrochemical sensors for chemical warfare agents.

    PubMed

    Khan, Mohammad A K; Long, Yi-Tao; Schatte, Gabriele; Kraatz, Heinz-Bernhard

    2007-04-01

    The cystamine conjugate [(BocNH)Fc(CO)CSA]2 was prepared by coupling cystamine with the N-protected ferrocene amino acid derivative BocHN-Fc-COOH and was fully characterized by spectroscopic methods and by single-crystal X-ray diffraction. The cystamine conjugate forms films on gold substrates, which upon deprotection of the amino group, react with chemical warfare agent (CWA) mimics, upon which the redox properties of the Fc group are affected significantly. Cyclic voltammetry shows 50(5) mV anodic shifts of the Fc redox potentials after exposure to EtSCH2CH2Cl, a simulant for sulfur mustard HD (MA), and (NC)(EtO)2P(O), a simulant for nerve agent Tabun (NA). Exposure to MA and NA causes an increase in 2.3 and 4.5 ng mass, respectively, in QCM which indicates ca. 70% efficiency in Boc-deprotection. Ellipsometry measured a film thickness increase from 6(+/-1) A for the deprotected film to 10(+/-4) A for the film modified with MA and to 7(+/-2) A for the film modified with NA. AFM measurements show changes in the thickness and morphology of the film after reaction with MA and NA. The surfaces were analyzed by X-ray photoelectron spectroscopy (XPS) and clearly show the attachment of the cystamine conjugate on the surface and its reaction with CWA mimics. PMID:17319647

  4. Modeling the transport of chemical warfare agents and simulants in polymeric substrates for reactive decontamination

    NASA Astrophysics Data System (ADS)

    Pearl, Thomas; Mantooth, Brent; Varady, Mark; Willis, Matthew

    2014-03-01

    Chemical warfare agent simulants are often used for environmental testing in place of highly toxic agents. This work sets the foundation for modeling decontamination of absorbing polymeric materials with the focus on determining relationships between agents and simulants. The correlations of agents to simulants must consider the three way interactions in the chemical-material-decontaminant system where transport and reaction occur in polymer materials. To this end, diffusion modeling of the subsurface transport of simulants and live chemical warfare agents was conducted for various polymer systems (e.g., paint coatings) with and without reaction pathways with applied decontamination. The models utilized 1D and 2D finite difference diffusion and reaction models to simulate absorption and reaction in the polymers, and subsequent flux of the chemicals out of the polymers. Experimental data including vapor flux measurements and dynamic contact angle measurements were used to determine model input parameters. Through modeling, an understanding of the relationship of simulant to live chemical warfare agent was established, focusing on vapor emission of agents and simulants from materials.

  5. Ion mobility spectrometric analysis of vaporous chemical warfare agents by the instrument with corona discharge ionization ammonia dopant ambient temperature operation.

    PubMed

    Satoh, Takafumi; Kishi, Shintaro; Nagashima, Hisayuki; Tachikawa, Masumi; Kanamori-Kataoka, Mieko; Nakagawa, Takao; Kitagawa, Nobuyoshi; Tokita, Kenichi; Yamamoto, Soichiro; Seto, Yasuo

    2015-03-20

    The ion mobility behavior of nineteen chemical warfare agents (7 nerve gases, 5 blister agents, 2 lachrymators, 2 blood agents, 3 choking agents) and related compounds including simulants (8 agents) and organic solvents (39) was comparably investigated by the ion mobility spectrometry instrument utilizing weak electric field linear drift tube with corona discharge ionization, ammonia doping, purified inner air drift flow circulation operated at ambient temperature and pressure. Three alkyl methylphosphonofluoridates, tabun, and four organophosphorus simulants gave the intense characteristic positive monomer-derived ion peaks and small dimer-derived ion peaks, and the later ion peaks were increased with the vapor concentrations. VX, RVX and tabun gave both characteristic positive monomer-derived ions and degradation product ions. Nitrogen mustards gave the intense characteristic positive ion peaks, and in addition distinctive negative ion peak appeared from HN3. Mustard gas, lewisite 1, o-chlorobenzylidenemalononitrile and 2-mercaptoethanol gave the characteristic negative ion peaks. Methylphosphonyl difluoride, 2-chloroacetophenone and 1,4-thioxane gave the characteristic ion peaks both in the positive and negative ion mode. 2-Chloroethylethylsulfide and allylisothiocyanate gave weak ion peaks. The marker ion peaks derived from two blood agents and three choking agents were very close to the reactant ion peak in negative ion mode and the respective reduced ion mobility was fluctuated. The reduced ion mobility of the CWA monomer-derived peaks were positively correlated with molecular masses among structurally similar agents such as G-type nerve gases and organophosphorus simulants; V-type nerve gases and nitrogen mustards. The slope values of the calibration plots of the peak heights of the characteristic marker ions versus the vapor concentrations are related to the detection sensitivity, and within chemical warfare agents examined the slope values for sarin, soman

  6. Optical detection of chemical warfare agents and toxic industrial chemicals

    NASA Astrophysics Data System (ADS)

    Webber, Michael E.; Pushkarsky, Michael B.; Patel, C. Kumar N.

    2004-12-01

    We present an analytical model evaluating the suitability of optical absorption based spectroscopic techniques for detection of chemical warfare agents (CWAs) and toxic industrial chemicals (TICs) in ambient air. The sensor performance is modeled by simulating absorption spectra of a sample containing both the target and multitude of interfering species as well as an appropriate stochastic noise and determining the target concentrations from the simulated spectra via a least square fit (LSF) algorithm. The distribution of the LSF target concentrations determines the sensor sensitivity, probability of false positives (PFP) and probability of false negatives (PFN). The model was applied to CO2 laser based photoacosutic (L-PAS) CWA sensor and predicted single digit ppb sensitivity with very low PFP rates in the presence of significant amount of interferences. This approach will be useful for assessing sensor performance by developers and users alike; it also provides methodology for inter-comparison of different sensing technologies.

  7. Fingerprinting malathion vapor: a simulant for VX nerve agent

    NASA Astrophysics Data System (ADS)

    Song, Renbo; Ding, Yujie J.; Zotova, Ioulia B.

    2008-04-01

    Being motivated by the possibility of fingerprinting and detecting VX nerve agent, we have investigated its stimulant, i.e. malathion vapor, which is less toxic and commercially available, in the far-infrared/THz transition region and THz frequency range. Such a spectroscopic study was carried out by using Fourier transform infrared spectroscopy (FTIR). Our intention is to obtain a specific spectroscopic signature of VX nerve agent as a chemical warfare agent. Following our experimental result, we have successfully observed eleven new absorption peaks from malathion vapor in the spectral ranges from 15 cm -1 to 68 cm -1 and from 75 cm -1 to 640 cm -1. Specifically, in the far-infrared/THz transition region, we have observed eight peaks and whereas in the THz region we have identified three relatively weak transition peaks. In addition, we have investigated the dependence of the absorption spectra on temperature in the range from room temperature to 60°C. In both of the frequency ranges, we have found that absorption coefficients significantly increase with increasing temperature. By comparing the transition peaks in the two frequency ranges, we have concluded that the frequency range of 400-640cm -1 is an optimal range for fingerprinting this chemical specie. We have designated two peaks for effectively and accurately identifying the VX nerve agents and one peak for differentiating between malathion and VX nerve agent.

  8. A Participatory Agent-Based Simulation for Indoor Evacuation Supported by Google Glass.

    PubMed

    Sánchez, Jesús M; Carrera, Álvaro; Iglesias, Carlos Á; Serrano, Emilio

    2016-01-01

    Indoor evacuation systems are needed for rescue and safety management. One of the challenges is to provide users with personalized evacuation routes in real time. To this end, this project aims at exploring the possibilities of Google Glass technology for participatory multiagent indoor evacuation simulations. Participatory multiagent simulation combines scenario-guided agents and humans equipped with Google Glass that coexist in a shared virtual space and jointly perform simulations. The paper proposes an architecture for participatory multiagent simulation in order to combine devices (Google Glass and/or smartphones) with an agent-based social simulator and indoor tracking services. PMID:27563911

  9. Nanowire-based surface-enhanced Raman spectroscopy (SERS) for chemical warfare simulants

    NASA Astrophysics Data System (ADS)

    Hoffmann, J. A.; Miragliotta, J. A.; Wang, J.; Tyagi, P.; Maddanimath, T.; Gracias, D. H.; Papadakis, S. J.

    2012-06-01

    Hand-held instruments capable of spectroscopic identification of chemical warfare agents (CWA) would find extensive use in the field. Because CWA can be toxic at very low concentrations compared to typical background levels of commonly-used compounds (flame retardants, pesticides) that are chemically similar, spectroscopic measurements have the potential to reduce false alarms by distinguishing between dangerous and benign compounds. Unfortunately, most true spectroscopic instruments (infrared spectrometers, mass spectrometers, and gas chromatograph-mass spectrometers) are bench-top instruments. Surface-acoustic wave (SAW) sensors are commercially available in hand-held form, but rely on a handful of functionalized surfaces to achieve specificity. Here, we consider the potential for a hand-held device based on surface enhanced Raman scattering (SERS) using templated nanowires as enhancing substrates. We examine the magnitude of enhancement generated by the nanowires and the specificity achieved in measurements of a range of CWA simulants. We predict the ultimate sensitivity of a device based on a nanowire-based SERS core to be 1-2 orders of magnitude greater than a comparable SAW system, with a detection limit of approximately 0.01 mg m-3.

  10. Chromogenic and fluorogenic detection of a nerve agent simulant with a rhodamine-deoxylactam based sensor.

    PubMed

    Wu, Xuanjun; Wu, Zhisheng; Han, Shoufa

    2011-11-01

    A chromogenic and fluorogenic detection of a nerve agent simulant was developed based on diethyl chlorophosphate triggered tandem phosphorylation and intramolecular cyclization of N-(rhodamine B)-deoxylactam-2-aminoethanol. PMID:21952323

  11. Fluorescence cross section measurements of biological agent simulants

    SciTech Connect

    Stephens, J.R.

    1996-11-01

    Fluorescence is a powerful technique that has potential uses in detection and characterization of biological aerosols both in the battlefield and in civilian environments. Fluorescence techniques can be used with ultraviolet (UV) light detection and ranging (LIDAR) equipment to detect biological aerosol clouds at a distance, to provide early warning of a biological attack, and to track an potentially noxious cloud. Fluorescence can also be used for detection in a point sensor to monitor biological materials and to distinguish agents from benign aerosols. This work is part of a continuing program by the Army`s Chemical and Biological Defense Command to characterized the optical properties of biological agents. Reported here are ultraviolet fluorescence measurements of Bacillus megaterium and Bacillus Globigii aerosols suspended in an electrodynamic particle trap. Fluorescence spectra of a common atmospheric aerosol, pine pollen, are also presented.

  12. CWA stand-off detection, a new figure-of-merit: the field surface scanning rate

    NASA Astrophysics Data System (ADS)

    Bernascolle, Philippe F.

    2013-05-01

    All the manufacturers of stand-off CWA detectors communicate on the "same" characteristics. And one can find these parameters in the comparison table published between all the different products [1]. These characteristics are for example the maximum detection range, the number of different detectable compounds, the weight, the price, etc… All these parameters are good to compare products between them, but they omit one very important point: the reaction time in case of an unexpected incoming chemical threat, in the case of the surveillance application. To answer this important question, we imagine a new parameter: the Field Surface Scanning Rate (FSSR). This value is a classical parameter in astronomical survey, use by astronomers to compare the performance of different telescopes, they compute the quantity of sky (in sky square degrees) analyzed per unit of time by the system. In this paper we will compare this new figure-of-merit, the FSSR, of some commercially off the shelf stand-off detector. The comparison between classical FTIR system and gas imaging system in term of FSSR will be presented.

  13. Experimental Simulations for Elimination of Biological and/or Chemical Agents

    NASA Astrophysics Data System (ADS)

    Hong, Yong C.; Kim, Jeong H.; Uhm, Han S.

    2003-10-01

    The threat of biological and/or chemical agents in a domestic terrorist attack and in military conflict is increasing worldwide. The 2oo1 anthrax terror throughout the USA, 1995 sarin nerve gas attack on Tokyo subway, and the like are evident for this threat. Elimination and decontamination of biological and/or chemical agents are needed for such an attack. Experimental simulation for elimination of biological and/or chemical agents using an atmospheric-pressure microwave plasma torch is carried out. The elimination of biological and/or chemical agents through the vitrification or burnout of sewage sludge powders and the decomposition of toluene gas as a chemical agent stimulant is presented. A detailed characterization for the elimination of the simulant chemicals using Fourier Transform Infrared (FT-IR) and Gas Chromatography (GC) is also presented.

  14. Protocol for determination of chemical warfare agent simulant movement through porous media

    SciTech Connect

    Jenkins, R.A.; Buchanan, M.V.; Merriweather, R.; Ilgner, R.H.; Gayle, T.M.; Moneyhun, J.H.; Watson, A.P.

    1992-07-01

    In the event of an unplanned release of chemical warfare agent during any phase of the Chemical Stockpile Disposal Program (CSDP), a (small) potential exists for contamination of buildings and materials used in their construction. Guidelines for unrestricted access to potentially agent-contaminated private and public property are presently undefined due to uncertainties regarding the adequacy of decontaminating porous surfaces such as wood, masonry and gypsum wall board. Persistent agents such as VX or mustard are particularly problematic. The report which follows documents a measurement protocol developed in a scoping investigation characterizing the permeation of chemical warfare agent simulants (diisopropylmethyl phosphonate (DIMP) for warfare agent GB, dimethylmethyl phosphonate (DMMP) for warfare agent VX and chlorethylethyl sulfide (CEES) for warfare agent sulfur mustard) through several, common porous, construction materials. The porous media'' selected for examination were wood, brick, cinder block, and gypsum wall board. Simulants were tested rather than actual warfare agents because of their low toxicity, commercial availability, and the lack of surety capability at Oak Ridge National Laboratory (ORNL). The present work is considered a protocol for confirmation testing with live'' agents.

  15. Protocol for determination of chemical warfare agent simulant movement through porous media

    SciTech Connect

    Jenkins, R.A.; Buchanan, M.V.; Merriweather, R.; Ilgner, R.H.; Gayle, T.M.; Moneyhun, J.H.; Watson, A.P.

    1992-07-01

    In the event of an unplanned release of chemical warfare agent during any phase of the Chemical Stockpile Disposal Program (CSDP), a (small) potential exists for contamination of buildings and materials used in their construction. Guidelines for unrestricted access to potentially agent-contaminated private and public property are presently undefined due to uncertainties regarding the adequacy of decontaminating porous surfaces such as wood, masonry and gypsum wall board. Persistent agents such as VX or mustard are particularly problematic. The report which follows documents a measurement protocol developed in a scoping investigation characterizing the permeation of chemical warfare agent simulants [diisopropylmethyl phosphonate (DIMP) for warfare agent GB, dimethylmethyl phosphonate (DMMP) for warfare agent VX and chlorethylethyl sulfide (CEES) for warfare agent sulfur mustard] through several, common porous, construction materials. The ``porous media`` selected for examination were wood, brick, cinder block, and gypsum wall board. Simulants were tested rather than actual warfare agents because of their low toxicity, commercial availability, and the lack of surety capability at Oak Ridge National Laboratory (ORNL). The present work is considered a protocol for confirmation testing with ``live`` agents.

  16. Large-scale multi-agent transportation simulations

    NASA Astrophysics Data System (ADS)

    Cetin, Nurhan; Nagel, Kai; Raney, Bryan; Voellmy, Andreas

    2002-08-01

    It is now possible to microsimulate the traffic of whole metropolitan areas with 10 million travelers or more, "micro" meaning that each traveler is resolved individually as a particle. In contrast to physics or chemistry, these particles have internal intelligence; for example, they know where they are going. This means that a transportation simulation project will have, besides the traffic microsimulation, modules which model this intelligent behavior. The most important modules are for route generation and for demand generation. Demand is generated by each individual in the simulation making a plan of activities such as sleeping, eating, working, shopping, etc. If activities are planned at different locations, they obviously generate demand for transportation. This however is not enough since those plans are influenced by congestion which initially is not known. This is solved via a relaxation method, which means iterating back and forth between the activities/routes generation and the traffic simulation.

  17. A study of the simulated evolution of the spectral sensitivity of visual agent receptors.

    PubMed

    Liese, A; Polani, D; Uthmann, T

    2001-01-01

    In this article we study a model for the evolution of the spectral sensitivity of visual receptors for agents in a continuous virtual environment. The model uses a genetic algorithm (GA) to evolve the agent sensors along with the control of the agents by requiring the agents to solve certain tasks in the simulation environment. The properties of the evolved sensors are analyzed for different scenarios. In particular, it is shown that the GA is able to find a balance between sensor costs and agent performance in such a way that the spectral sensor sensitivity reflects the emission spectrum of the target objects and that the capability of the sensors to evolve can help the agents significantly in adapting to their task. PMID:11580876

  18. Simulated Environments with Animated Agents: Effects on Visual Attention, Emotion, Performance, and Perception

    ERIC Educational Resources Information Center

    Romero-Hall, E.; Watson, G. S.; Adcock, A.; Bliss, J.; Adams Tufts, K.

    2016-01-01

    This research assessed how emotive animated agents in a simulation-based training affect the performance outcomes and perceptions of the individuals interacting in real time with the training application. A total of 56 participants consented to complete the study. The material for this investigation included a nursing simulation in which…

  19. Terahertz signatures of biological-warfare-agent simulants

    NASA Astrophysics Data System (ADS)

    Globus, Tatiana; Woolard, Dwight L.; Khromova, Tatyana; Partasarathy, Ramakrishnan; Majewski, Alexander; Abreu, Rene; Hesler, Jeffrey L.; Pan, Shing-Kuo; Ediss, Geoff

    2004-09-01

    This work presents spectroscopic characterization results for biological simulant materials measured in the terahertz gap. Signature data have been collected between 3 cm-1 and 10 cm-1 for toxin Ovalbumin, bacteria Erwinia herbicola, Bacillus Subtilis lyophilized cells and RNA MS2 phage, BioGene. Measurements were conducted on a modified Bruker FTIR spectrometer equipped with the noise source developed in the NRAL. The noise source provides two orders of magnitude higher power in comparison with a conventional mercury lamp. Photometric characterization of the instrument performance demonstrates that the expected error for sample characterization inside the interval from 3 to 9.5 cm-1 is less then 1%.

  20. Selection of an averaging technique by simulation study of a DIAL system for toxic agents monitoring

    NASA Astrophysics Data System (ADS)

    Dudeja, Jai Paul; Jindal, Mukesh Kumar; Veerabuthiran, S.

    2007-10-01

    Differential Absorption Lidar (DIAL) is a very effective technique for standoff detection of various toxic agents in the atmosphere. The Lidar backscattered signal received usually has poor signal to noise (SNR) ratio. In order to improve the SNR, statistical averaging over a number of laser pulses is employed. The aim of the present work is to select a particular statistical averaging technique, which is most suitable in removing the noise in Lidar return signals. The DIAL system considered here uses laser transmitters based on OPO based (2-5 μm) and TEA CO2 (9-11μm) lasers. Eight commonly used chemical warfare agents including five nerve agents and three blister agents have been considered here as examples of toxic agents. A Graphical User Interface (GUI) software has been developed in LabVIEW to simulate return signals mixed with the expected noise levels. A toxic agent cloud with a given thickness and concentration has been assumed to be detected in the ambient atmospheric conditions at various ranges up to 5 Km. Data for 200 pulses per agent was stored in the computer memory. Various known statistical averaging techniques were used and number concentrations of particular agent have been computed and compared with ideal Lidar return signal values. This exercise was repeated for all the eight agents and based on the results obtained; the most suitable averaging technique has been selected.

  1. Wireless Hazard Badges to Detect Nerve-Agent Simulants.

    PubMed

    Zhu, Rong; Azzarelli, Joseph M; Swager, Timothy M

    2016-08-01

    Human exposure to hazardous chemicals can have adverse short- and long-term health effects. In this Communication, we have developed a single-use wearable hazard badge that dosimetrically detects diethylchlorophosphate (DCP), a model organophosphorous cholinesterase inhibitor simulant. Improved chemically actuated resonant devices (CARDs) are fabricated in a single step and unambiguously relate changes in chemiresistance to a wireless readout. To provide selective and readily manufacturable sensor elements for this platform, we developed an ionic-liquid-mediated single walled carbon nanotube based chemidosimetric scheme with DCP limits of detection of 28 ppb. As a practical demonstration, an 8 h workday time weighted average equivalent exposure of 10 ppb DCP effects an irreversible change in smartphone readout. PMID:27384415

  2. Method for distributed agent-based non-expert simulation of manufacturing process behavior

    DOEpatents

    Ivezic, Nenad; Potok, Thomas E.

    2004-11-30

    A method for distributed agent based non-expert simulation of manufacturing process behavior on a single-processor computer comprises the steps of: object modeling a manufacturing technique having a plurality of processes; associating a distributed agent with each the process; and, programming each the agent to respond to discrete events corresponding to the manufacturing technique, wherein each discrete event triggers a programmed response. The method can further comprise the step of transmitting the discrete events to each agent in a message loop. In addition, the programming step comprises the step of conditioning each agent to respond to a discrete event selected from the group consisting of a clock tick message, a resources received message, and a request for output production message.

  3. Reactively and Anticipatory Behaving Agents for Artificial Life Simulations

    NASA Astrophysics Data System (ADS)

    Kohout, Karel; Nahodil, Pavel

    2010-11-01

    Reactive behavior is still considered and the exact opposite for the anticipatory one. Despite the advances on the field of anticipation there are little thoughts on relation with the reactive behavior, the similarities and where the boundary is. In this article we will present our viewpoint and we will try to show that reactive and anticipatory behavior can be combined. This is the basic ground of our unified theory for anticipatory behavior architecture. We still miss such compact theory, which would integrate multiple aspects of anticipation. My multi-level anticipatory behavior approach is based on the current understanding of anticipation from both the artificial intelligence and biology point of view. As part of the explanation we will also elaborate on the topic of weak and strong artificial life. Anticipation is not matter of a single mechanism in a living organism. It was noted already that it happens on many different levels even in the very simple creatures. What we consider to be important for our work and what is our original though is that it happens even without voluntary control. We believe that this is novelty though for the anticipation theory. Naturally research of anticipation was in the beginning of this decade focused on the anticipatory principles bringing advances on the field itself. This allowed us to build on those, look at them from higher perspective, and use not one but multiple levels of anticipation in a creature design. This presents second original though and that is composition of the agent architecture that has anticipation built in almost every function. In this article we will focus only on first two levels within the 8-factor anticipation framework. We will introduce them as defined categories of anticipation and describe them from theory and implementation algorithm point of view. We will also present an experiment conducted, however this experiment serves more as explanatory example. These first two levels may seem trivial

  4. Chemical Computer Man: Chemical Agent Response Simulation (CARS). Technical report, January 1983-September 1985

    SciTech Connect

    Davis, E.G.; Mioduszewski, R.J.

    1988-03-01

    The Chemical Computer Man: Chemical Agent Response Simulation (CARS) is a computer model and simulation program for estimating the dynamic changes in human physiological dysfunction resulting from exposures to chemical-threat nerve agents. The newly developed CARS methodology simulates agent exposure effects on the following five indices of human physiological function: mental, vision, cardio-respiratory, visceral, and limbs. Mathematical models and the application of basic pharmacokinetic principles were incorporated into the simulation so that for each chemical exposure, the relationship between exposure dosage, absorbed dosage (agent blood plasma concentration), and level of physiological response are computed as a function of time. CARS, as a simulation tool, is designed for the users with little or no computer-related experience. The model combines maximum flexibility with a comprehensive user-friendly interactive menu-driven system. Users define an exposure problem and obtain immediate results displayed in tabular, graphical, and image formats. CARS has broad scientific and engineering applications, not only in technology for the soldier in the area of Chemical Defense, but also in minimizing animal testing in biomedical and toxicological research and the development of a modeling system for human exposure to hazardous-waste chemicals.

  5. Agent-based simulation of building evacuation using a grid graph-based model

    NASA Astrophysics Data System (ADS)

    Tan, L.; Lin, H.; Hu, M.; Che, W.

    2014-02-01

    Shifting from macroscope models to microscope models, the agent-based approach has been widely used to model crowd evacuation as more attentions are paid on individualized behaviour. Since indoor evacuation behaviour is closely related to spatial features of the building, effective representation of indoor space is essential for the simulation of building evacuation. The traditional cell-based representation has limitations in reflecting spatial structure and is not suitable for topology analysis. Aiming at incorporating powerful topology analysis functions of GIS to facilitate agent-based simulation of building evacuation, we used a grid graph-based model in this study to represent the indoor space. Such model allows us to establish an evacuation network at a micro level. Potential escape routes from each node thus could be analysed through GIS functions of network analysis considering both the spatial structure and route capacity. This would better support agent-based modelling of evacuees' behaviour including route choice and local movements. As a case study, we conducted a simulation of emergency evacuation from the second floor of an official building using Agent Analyst as the simulation platform. The results demonstrate the feasibility of the proposed method, as well as the potential of GIS in visualizing and analysing simulation results.

  6. Studies on residue-free decontaminants for chemical warfare agents.

    PubMed

    Wagner, George W

    2015-03-17

    Residue-free decontaminants based on hydrogen peroxide, which decomposes to water and oxygen in the environment, are examined as decontaminants for chemical warfare agents (CWA). For the apparent special case of CWA on concrete, H2O2 alone, without any additives, effectively decontaminates S-2-(diisopropylamino)ethyl O-ethyl methylphosphonothioate (VX), pinacolyl methylphosphorofluoridate (GD), and bis(2-choroethyl) sulfide (HD) in a process thought to involve H2O2 activation by surface-bound carbonates/bicarbonates (known H2O2 activators for CWA decontamination). A plethora of products are formed during the H2O2 decontamination of HD on concrete, and these are characterized by comparison to synthesized authentic compounds. As a potential residue-free decontaminant for surfaces other than concrete (or those lacking adsorbed carbonate/bicarbonate) H2O2 activation for CWA decontamination is feasible using residue-free NH3 and CO2 as demonstrated by reaction studies for VX, GD, and HD in homogeneous solution. Although H2O2/NH3/CO2 ("HPAC") decontaminants are active for CWA decontamination in solution, they require testing on actual surfaces of interest to assess their true efficacy for surface decontamination. PMID:25710477

  7. Design and simulation of material-integrated distributed sensor processing with a code-based agent platform and mobile multi-agent systems.

    PubMed

    Bosse, Stefan

    2015-01-01

    Multi-agent systems (MAS) can be used for decentralized and self-organizing data processing in a distributed system, like a resource-constrained sensor network, enabling distributed information extraction, for example, based on pattern recognition and self-organization, by decomposing complex tasks in simpler cooperative agents. Reliable MAS-based data processing approaches can aid the material-integration of structural-monitoring applications, with agent processing platforms scaled to the microchip level. The agent behavior, based on a dynamic activity-transition graph (ATG) model, is implemented with program code storing the control and the data state of an agent, which is novel. The program code can be modified by the agent itself using code morphing techniques and is capable of migrating in the network between nodes. The program code is a self-contained unit (a container) and embeds the agent data, the initialization instructions and the ATG behavior implementation. The microchip agent processing platform used for the execution of the agent code is a standalone multi-core stack machine with a zero-operand instruction format, leading to a small-sized agent program code, low system complexity and high system performance. The agent processing is token-queue-based, similar to Petri-nets. The agent platform can be implemented in software, too, offering compatibility at the operational and code level, supporting agent processing in strong heterogeneous networks. In this work, the agent platform embedded in a large-scale distributed sensor network is simulated at the architectural level by using agent-based simulation techniques. PMID:25690550

  8. Design and Simulation of Material-Integrated Distributed Sensor Processing with a Code-Based Agent Platform and Mobile Multi-Agent Systems

    PubMed Central

    Bosse, Stefan

    2015-01-01

    Multi-agent systems (MAS) can be used for decentralized and self-organizing data processing in a distributed system, like a resource-constrained sensor network, enabling distributed information extraction, for example, based on pattern recognition and self-organization, by decomposing complex tasks in simpler cooperative agents. Reliable MAS-based data processing approaches can aid the material-integration of structural-monitoring applications, with agent processing platforms scaled to the microchip level. The agent behavior, based on a dynamic activity-transition graph (ATG) model, is implemented with program code storing the control and the data state of an agent, which is novel. The program code can be modified by the agent itself using code morphing techniques and is capable of migrating in the network between nodes. The program code is a self-contained unit (a container) and embeds the agent data, the initialization instructions and the ATG behavior implementation. The microchip agent processing platform used for the execution of the agent code is a standalone multi-core stack machine with a zero-operand instruction format, leading to a small-sized agent program code, low system complexity and high system performance. The agent processing is token-queue-based, similar to Petri-nets. The agent platform can be implemented in software, too, offering compatibility at the operational and code level, supporting agent processing in strong heterogeneous networks. In this work, the agent platform embedded in a large-scale distributed sensor network is simulated at the architectural level by using agent-based simulation techniques. PMID:25690550

  9. A framework for service enterprise workflow simulation with multi-agents cooperation

    NASA Astrophysics Data System (ADS)

    Tan, Wenan; Xu, Wei; Yang, Fujun; Xu, Lida; Jiang, Chuanqun

    2013-11-01

    Process dynamic modelling for service business is the key technique for Service-Oriented information systems and service business management, and the workflow model of business processes is the core part of service systems. Service business workflow simulation is the prevalent approach to be used for analysis of service business process dynamically. Generic method for service business workflow simulation is based on the discrete event queuing theory, which is lack of flexibility and scalability. In this paper, we propose a service workflow-oriented framework for the process simulation of service businesses using multi-agent cooperation to address the above issues. Social rationality of agent is introduced into the proposed framework. Adopting rationality as one social factor for decision-making strategies, a flexible scheduling for activity instances has been implemented. A system prototype has been developed to validate the proposed simulation framework through a business case study.

  10. Experimental examination of ultraviolet Raman cross sections of chemical warfare agent simulants

    NASA Astrophysics Data System (ADS)

    Kullander, F.; Landström, L.; Lundén, H.; Wästerby, Pär.

    2015-05-01

    Laser induced Raman scattering from the commonly used chemical warfare agent simulants dimethyl sulfoxide, tributyl phosphate, triethyl phosphonoacetate was measured at excitation wavelengths ranging from 210 to 410 nm using a pulsed laser based spectrometer system with a probing distance of 1.4 m and with a field of view on the target of less than 1mm. For the purpose of comparison with well explored reference liquids the Raman scattering from simulants was measured in the form of an extended liquid surface layer on top of a silicon wafer. This way of measuring enabled direct comparison to the Raman scattering strength from cyclohexane. The reference Raman spectra were used to validate the signal strength of the simulants and the calibration of the experimental set up. Measured UV absorbance functions were used to calculate Raman cross sections. Established Raman cross sections of the simulants make it possible to use them as reference samples when measuring on chemical warfare agents in droplet form.

  11. Using an Agent-Supported Simulation Environment for Intelligent Manufacturing Systems

    NASA Astrophysics Data System (ADS)

    Ruiz, Nancy; Giret, Adriana; Botti, Vicente

    The manufacturing field is an area where the application of simulation is an essential tool for validating methods and architectures before applying them on the factory floor. Multiagent System technology has demonstrated its utility in manufacturing system modeling and implementation. Agenthood features such as proactivity, reactivity, and sociability may also be useful for associating them with the specific simulation needs of the new manufacturing requirements. In this paper, we present an Agent-supported Simulation Tool (tool uses both events and discrete time to control agent tasks) for Intelligent Manufacturing Systems applied to a real manufacturing enterprise case study. The main goal is to provide a flexible simulation tool that can be adapted to solve the new manufacturing requirements that appear in a real environment allowing the experts of manufacturing domains to optimize the resource usage and to have enough data to make decisions.

  12. [Research on multi-agent based modeling and simulation of hospital system].

    PubMed

    Zhao, Junping; Yang, Hongqiao; Guo, Huayuan; Li, Yi; Zhang, Zhenjiang; Li, Shuzhang

    2010-12-01

    In this paper, the theory of complex adaptive system (CAS) and its modeling method are introduced. The complex characters of the hospital system is analyzed. The agile manufacturing and cell reconstruction technologies are used to reconstruct the hospital system. Then we set forth a research for simulation of hospital system based on the methodology of Multi-Agent technology and high level architecture (HLA). Finally, a simulation framework based on HLA for hospital system is presented. PMID:21374992

  13. Agent-based evacuation simulation for spatial allocation assessment of urban shelters

    NASA Astrophysics Data System (ADS)

    Yu, Jia; Wen, Jiahong; Jiang, Yong

    2015-12-01

    The construction of urban shelters is one of the most important work in urban planning and disaster prevention. The spatial allocation assessment is a fundamental pre-step for spatial location-allocation of urban shelters. This paper introduces a new method which makes use of agent-based technology to implement evacuation simulation so as to conduct dynamic spatial allocation assessment of urban shelters. The method can not only accomplish traditional geospatial evaluation for urban shelters, but also simulate the evacuation process of the residents to shelters. The advantage of utilizing this method lies into three aspects: (1) the evacuation time of each citizen from a residential building to the shelter can be estimated more reasonably; (2) the total evacuation time of all the residents in a region is able to be obtained; (3) the road congestions in evacuation in sheltering can be detected so as to take precautionary measures to prevent potential risks. In this study, three types of agents are designed: shelter agents, government agents and resident agents. Shelter agents select specified land uses as shelter candidates for different disasters. Government agents delimitate the service area of each shelter, in other words, regulate which shelter a person should take, in accordance with the administrative boundaries and road distance between the person's position and the location of the shelter. Resident agents have a series of attributes, such as ages, positions, walking speeds, and so on. They also have several behaviors, such as reducing speed when walking in the crowd, helping old people and children, and so on. Integrating these three types of agents which are correlated with each other, evacuation procedures can be simulated and dynamic allocation assessment of shelters will be achieved. A case study in Jing'an District, Shanghai, China, was conducted to demonstrate the feasibility of the method. A scenario of earthquake disaster which occurs in nighttime

  14. Use of agent-based simulations to design and interpret HIV clinical trials.

    PubMed

    Cuadros, Diego F; Abu-Raddad, Laith J; Awad, Susanne F; García-Ramos, Gisela

    2014-07-01

    In this study, we illustrate the utility of an agent-based simulation to inform a trial design and how this supports outcome interpretation of randomized controlled trials (RCTs). We developed agent-based Monte Carlo models to simulate existing landmark HIV RCTs, such as the Partners in Prevention HSV/HIV Transmission Study. We simulated a variation of this study using valacyclovir therapy as the intervention, and we used a male circumcision RCT based on the Rakai Male Circumcision Trial. Our results indicate that a small fraction (20%) of the simulated Partners in Prevention HSV/HIV Transmission Study realizations rejected the null hypothesis, which was no effect from the intervention. Our results also suggest that an RCT designed to evaluate the effectiveness of a more potent drug regimen for HSV-2 suppression (valacyclovir therapy) is more likely to identify the efficacy of the intervention. For the male circumcision RCT simulation, the greater biological effect of the male circumcision yielded a major fraction (81%) of RCT realizations' that rejects the null hypothesis, which was no effect from the intervention. Our study highlights how agent-based simulations synthesize individual variation in the epidemiological context of the RCT. This methodology will be particularly useful for designing RCTs aimed at evaluating combination prevention interventions in community-based RCTs, wherein an intervention׳s effectiveness is challenging to predict. PMID:24792492

  15. Design of a Mobile Agent-Based Adaptive Communication Middleware for Federations of Critical Infrastructure Simulations

    NASA Astrophysics Data System (ADS)

    Görbil, Gökçe; Gelenbe, Erol

    The simulation of critical infrastructures (CI) can involve the use of diverse domain specific simulators that run on geographically distant sites. These diverse simulators must then be coordinated to run concurrently in order to evaluate the performance of critical infrastructures which influence each other, especially in emergency or resource-critical situations. We therefore describe the design of an adaptive communication middleware that provides reliable and real-time one-to-one and group communications for federations of CI simulators over a wide-area network (WAN). The proposed middleware is composed of mobile agent-based peer-to-peer (P2P) overlays, called virtual networks (VNets), to enable resilient, adaptive and real-time communications over unreliable and dynamic physical networks (PNets). The autonomous software agents comprising the communication middleware monitor their performance and the underlying PNet, and dynamically adapt the P2P overlay and migrate over the PNet in order to optimize communications according to the requirements of the federation and the current conditions of the PNet. Reliable communications is provided via redundancy within the communication middleware and intelligent migration of agents over the PNet. The proposed middleware integrates security methods in order to protect the communication infrastructure against attacks and provide privacy and anonymity to the participants of the federation. Experiments with an initial version of the communication middleware over a real-life networking testbed show that promising improvements can be obtained for unicast and group communications via the agent migration capability of our middleware.

  16. Metal organic frameworks (MOFs) for degrdation of nerve agent simulant parathion

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Parathion, a simulant of nerve agent VX, has been studied for degradation on Fe3+, Fe2+ and zerovalent iron supported on chitosan. Chitosan, a naturally occurring biopolymer derivative of chitin, is a very good adsorbent for many chemicals including metals. Chitosan is used as supporting biopolymer ...

  17. An agent-based simulation of extirpation of Ceratitis capitata applied to invasions in California

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We describe and validate an Agent-Based Simulation(ABS) of invasive insects and use it to investigate the time to extirpation of Ceratitis capitata using data from seven outbreaks that occurred in California from 2008-2010. Results are compared with the length of intervention and quarantine imposed ...

  18. Fluorogenic and chromogenic probe for rapid detection of a nerve agent simulant DCP.

    PubMed

    Wu, Wei-hui; Dong, Jun-jun; Wang, Xin; Li, Jian; Sui, Shao-hui; Chen, Gao-yun; Liu, Ji-wei; Zhang, Ming

    2012-07-21

    A fluorogenic and visual probe was devised to detect diethyl chlorophosphate (DCP), a nerve agent simulant. The probe, N-(rhodamine B)-lactam-2-aminoethanol (RB-AE), undergoes oxazoline formation following phosphorylation in the presence of DCP, which gives rapid and clear fluorescence and color change in the assay solutions. PMID:22624148

  19. Efficient Allocation of Resources for Defense of Spatially Distributed Networks Using Agent-Based Simulation.

    PubMed

    Kroshl, William M; Sarkani, Shahram; Mazzuchi, Thomas A

    2015-09-01

    This article presents ongoing research that focuses on efficient allocation of defense resources to minimize the damage inflicted on a spatially distributed physical network such as a pipeline, water system, or power distribution system from an attack by an active adversary, recognizing the fundamental difference between preparing for natural disasters such as hurricanes, earthquakes, or even accidental systems failures and the problem of allocating resources to defend against an opponent who is aware of, and anticipating, the defender's efforts to mitigate the threat. Our approach is to utilize a combination of integer programming and agent-based modeling to allocate the defensive resources. We conceptualize the problem as a Stackelberg "leader follower" game where the defender first places his assets to defend key areas of the network, and the attacker then seeks to inflict the maximum damage possible within the constraints of resources and network structure. The criticality of arcs in the network is estimated by a deterministic network interdiction formulation, which then informs an evolutionary agent-based simulation. The evolutionary agent-based simulation is used to determine the allocation of resources for attackers and defenders that results in evolutionary stable strategies, where actions by either side alone cannot increase its share of victories. We demonstrate these techniques on an example network, comparing the evolutionary agent-based results to a more traditional, probabilistic risk analysis (PRA) approach. Our results show that the agent-based approach results in a greater percentage of defender victories than does the PRA-based approach. PMID:25683347

  20. Supercritical fluid extraction and organic solvent microextraction of chemical agent simulants from soil

    SciTech Connect

    Griest, W.H.; Ramsey, R.S.; Ho, C.h.; Caldwell, W.M.

    1991-12-31

    Experiments with chemical warfare agent simulants suggest that supercritical fluid extraction can achieve good extraction recoveries of agents in soil and produce less laboratory waste than current organic solvent extraction methods. Two-ppm spikes in 1 g of Rocky Mountain Arsenal Standard Soil were extracted using 5% methanol in carbon dioxide at 300 atm for 2 min at 60{degrees}C. Recoveries (n=3) were 79{plus_minus}23% for dimethylmethylphosphonate, 93{plus_minus}14% for 2-chlorethylethylsulfide, 92{plus_minus}13% for diisopropylfluorophosphate, and 95{plus_minus}17% for diisopropylmethylphosphonate. A 5 min ultrasonic micro-scale extraction using methanol is more reproducible but less efficient.

  1. Supercritical fluid extraction and organic solvent microextraction of chemical agent simulants from soil

    SciTech Connect

    Griest, W.H.; Ramsey, R.S.; Ho, C.h.; Caldwell, W.M.

    1991-01-01

    Experiments with chemical warfare agent simulants suggest that supercritical fluid extraction can achieve good extraction recoveries of agents in soil and produce less laboratory waste than current organic solvent extraction methods. Two-ppm spikes in 1 g of Rocky Mountain Arsenal Standard Soil were extracted using 5% methanol in carbon dioxide at 300 atm for 2 min at 60{degrees}C. Recoveries (n=3) were 79{plus minus}23% for dimethylmethylphosphonate, 93{plus minus}14% for 2-chlorethylethylsulfide, 92{plus minus}13% for diisopropylfluorophosphate, and 95{plus minus}17% for diisopropylmethylphosphonate. A 5 min ultrasonic micro-scale extraction using methanol is more reproducible but less efficient.

  2. A water market simulator considering pair-wise trades between agents

    NASA Astrophysics Data System (ADS)

    Huskova, I.; Erfani, T.; Harou, J. J.

    2012-04-01

    In many basins in England no further water abstraction licences are available. Trading water between water rights holders has been recognized as a potentially effective and economically efficient strategy to mitigate increasing scarcity. A screening tool that could assess the potential for trade through realistic simulation of individual water rights holders would help assess the solution's potential contribution to local water management. We propose an optimisation-driven water market simulator that predicts pair-wise trade in a catchment and represents its interaction with natural hydrology and engineered infrastructure. A model is used to emulate licence-holders' willingness to engage in short-term trade transactions. In their simplest form agents are represented using an economic benefit function. The working hypothesis is that trading behaviour can be partially predicted based on differences in marginal values of water over space and time and estimates of transaction costs on pair-wise trades. We discuss the further possibility of embedding rules, norms and preferences of the different water user sectors to more realistically represent the behaviours, motives and constraints of individual licence holders. The potential benefits and limitations of such a social simulation (agent-based) approach is contrasted with our simulator where agents are driven by economic optimization. A case study based on the Dove River Basin (UK) demonstrates model inputs and outputs. The ability of the model to suggest impacts of water rights policy reforms on trading is discussed.

  3. Rapid chemical agent identification by surface-enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Lee, Yuan-Hsiang; Farquharson, Stuart

    2001-08-01

    Although the Chemical Weapons Convention prohibits the development, production, stockpiling, and use of chemical warfare agents (CWAs), the use of these agents persists due to their low cost, simplicity in manufacturing and ease of deployment. These attributes make these weapons especially attractive to low technology countries and terrorists. The military and the public at large require portable, fast, sensitive, and accurate analyzers to provide early warning of the use of chemical weapons. Traditional laboratory analyzers such as the combination of gas chromatography and mass spectroscopy, although sensitive and accurate, are large and require up to an hour per analysis. New, chemical specific analyzers, such as immunoassays and molecular recognition sensors, are portable, fast, and sensitive, but are plagued by false-positives (response to interferents). To overcome these limitations, we have been investigating the potential of surface-enhanced Raman spectroscopy (SERS) to identify and quantify chemical warfare agents in either the gas or liquid phase. The approach is based on the extreme sensitivity of SERS demonstrated by single molecule detection, a new SERS material that we have developed to allow reproducible and reversible measurements, and the molecular specific information provided by Raman spectroscopy. Here we present SER spectra of chemical agent simulants in both the liquid and gas phase, as well as CWA hydrolysis phase.

  4. An Agent-Based Model of New Venture Creation: Conceptual Design for Simulating Entrepreneurship

    NASA Technical Reports Server (NTRS)

    Provance, Mike; Collins, Andrew; Carayannis, Elias

    2012-01-01

    There is a growing debate over the means by which regions can foster the growth of entrepreneurial activity in order to stimulate recovery and growth of their economies. On one side, agglomeration theory suggests the regions grow because of strong clusters that foster knowledge spillover locally; on the other side, the entrepreneurial action camp argues that innovative business models are generated by entrepreneurs with unique market perspectives who draw on knowledge from more distant domains. We will show you the design for a novel agent-based model of new venture creation that will demonstrate the relationship between agglomeration and action. The primary focus of this model is information exchange as the medium for these agent interactions. Our modeling and simulation study proposes to reveal interesting relationships in these perspectives, offer a foundation on which these disparate theories from economics and sociology can find common ground, and expand the use of agent-based modeling into entrepreneurship research.

  5. Simulating tissue mechanics with agent-based models: concepts, perspectives and some novel results

    NASA Astrophysics Data System (ADS)

    Van Liedekerke, P.; Palm, M. M.; Jagiella, N.; Drasdo, D.

    2015-12-01

    In this paper we present an overview of agent-based models that are used to simulate mechanical and physiological phenomena in cells and tissues, and we discuss underlying concepts, limitations, and future perspectives of these models. As the interest in cell and tissue mechanics increase, agent-based models are becoming more common the modeling community. We overview the physical aspects, complexity, shortcomings, and capabilities of the major agent-based model categories: lattice-based models (cellular automata, lattice gas cellular automata, cellular Potts models), off-lattice models (center-based models, deformable cell models, vertex models), and hybrid discrete-continuum models. In this way, we hope to assist future researchers in choosing a model for the phenomenon they want to model and understand. The article also contains some novel results.

  6. Measurement of drug facilitated sexual assault agents in simulated sweat by ion mobility spectrometry.

    PubMed

    Demoranville, Leonard T; Verkouteren, Jennifer R

    2013-03-15

    Ion mobility spectrometry has found widespread use for the detection of explosives and illicit drugs. The technique offers rapid results with high sensitivity and little sample preparation. As such, it is well suited for field deployed screening settings. Here the response of ion mobility spectrometers for three drug-facilitated sexual assault (DFSA) agents - flunitrazepam, ketamine, and MDMA - and related metabolites has been studied in the presence of a simulated sweat. While all three DFSA agents present certain challenges for qualitative identification, IMS can provide useful information to guide the early treatment and investigation of sexual assault cases. Used as a presumptive test, the identification of DFSA agents would later require confirmatory analysis by other techniques. PMID:23598140

  7. Comparing stochastic differential equations and agent-based modelling and simulation for early-stage cancer.

    PubMed

    Figueredo, Grazziela P; Siebers, Peer-Olaf; Owen, Markus R; Reps, Jenna; Aickelin, Uwe

    2014-01-01

    There is great potential to be explored regarding the use of agent-based modelling and simulation as an alternative paradigm to investigate early-stage cancer interactions with the immune system. It does not suffer from some limitations of ordinary differential equation models, such as the lack of stochasticity, representation of individual behaviours rather than aggregates and individual memory. In this paper we investigate the potential contribution of agent-based modelling and simulation when contrasted with stochastic versions of ODE models using early-stage cancer examples. We seek answers to the following questions: (1) Does this new stochastic formulation produce similar results to the agent-based version? (2) Can these methods be used interchangeably? (3) Do agent-based models outcomes reveal any benefit when compared to the Gillespie results? To answer these research questions we investigate three well-established mathematical models describing interactions between tumour cells and immune elements. These case studies were re-conceptualised under an agent-based perspective and also converted to the Gillespie algorithm formulation. Our interest in this work, therefore, is to establish a methodological discussion regarding the usability of different simulation approaches, rather than provide further biological insights into the investigated case studies. Our results show that it is possible to obtain equivalent models that implement the same mechanisms; however, the incapacity of the Gillespie algorithm to retain individual memory of past events affects the similarity of some results. Furthermore, the emergent behaviour of ABMS produces extra patters of behaviour in the system, which was not obtained by the Gillespie algorithm. PMID:24752131

  8. ActivitySim: large-scale agent based activity generation for infrastructure simulation

    SciTech Connect

    Gali, Emmanuel; Eidenbenz, Stephan; Mniszewski, Sue; Cuellar, Leticia; Teuscher, Christof

    2008-01-01

    The United States' Department of Homeland Security aims to model, simulate, and analyze critical infrastructure and their interdependencies across multiple sectors such as electric power, telecommunications, water distribution, transportation, etc. We introduce ActivitySim, an activity simulator for a population of millions of individual agents each characterized by a set of demographic attributes that is based on US census data. ActivitySim generates daily schedules for each agent that consists of a sequence of activities, such as sleeping, shopping, working etc., each being scheduled at a geographic location, such as businesses or private residences that is appropriate for the activity type and for the personal situation of the agent. ActivitySim has been developed as part of a larger effort to understand the interdependencies among national infrastructure networks and their demand profiles that emerge from the different activities of individuals in baseline scenarios as well as emergency scenarios, such as hurricane evacuations. We present the scalable software engineering principles underlying ActivitySim, the socia-technical modeling paradigms that drive the activity generation, and proof-of-principle results for a scenario in the Twin Cities, MN area of 2.6 M agents.

  9. Survey: Destruction of chemical agent simulants in supercritical water oxidation. Master's thesis

    SciTech Connect

    Blank, M.R.

    1992-07-01

    The supercritical water oxidation (SCWO) process exhibits distinct advantages for destruction of toxic wastes. Examples of these wastes are two chemical agent simulants, dimethyl methylphosphonate (DMMP) and thiodiglycol (2,2'-thiodiethanol). DMMP is similar to the nerve agent GB Sarin in structure, and thiodiglycol is a hydrolysis product of the blister agent HD Sulfur Mustard. Both simulants are miscible in water and relatively non-toxic in comparison to the actual chemical agents. Using a Laboratory-scale, batch three temperatures were investigated: 425 deg C, 450 deg C, and 500 deg C with an initial concentration of one percent by volume, 11,450 mg/L for DMMP and 12,220 mg/L for thiodiglycol. Residence times investigated were: 1, 2, 3, 6, and 8 minutes. Reactor beat-up (H.U.) was determined to be one minute. Both pyrolysis and oxidation tests were conducted. Oxygen levels were uniformly set at 200% of stoichiometric requirements for the parent compounds.

  10. Evolutionary Agent-Based Simulation of the Introduction of New Technologies in Air Traffic Management

    NASA Technical Reports Server (NTRS)

    Yliniemi, Logan; Agogino, Adrian K.; Tumer, Kagan

    2014-01-01

    Accurate simulation of the effects of integrating new technologies into a complex system is critical to the modernization of our antiquated air traffic system, where there exist many layers of interacting procedures, controls, and automation all designed to cooperate with human operators. Additions of even simple new technologies may result in unexpected emergent behavior due to complex human/ machine interactions. One approach is to create high-fidelity human models coming from the field of human factors that can simulate a rich set of behaviors. However, such models are difficult to produce, especially to show unexpected emergent behavior coming from many human operators interacting simultaneously within a complex system. Instead of engineering complex human models, we directly model the emergent behavior by evolving goal directed agents, representing human users. Using evolution we can predict how the agent representing the human user reacts given his/her goals. In this paradigm, each autonomous agent in a system pursues individual goals, and the behavior of the system emerges from the interactions, foreseen or unforeseen, between the agents/actors. We show that this method reflects the integration of new technologies in a historical case, and apply the same methodology for a possible future technology.

  11. IMPROVEMENT OF BUSINESS EFFICIENCY USING A MULTI-AGENT SIMULATION FOR HIGHWAY PATROL ON URBAN EXPRESSWAY

    NASA Astrophysics Data System (ADS)

    Okamoto, Taro; Taniguchi, Eiichi; Yamada, Tadashi

    In Japan, the network of urban expressway has been expanding with the development of urban areas. However, the patrol systems in the urban expressway has not been operated on the basis of scientific evidence, but of conformity and experience. It is therefore crucial to efficiently operate such systems, not only to facilitate the rapid recovery of decreased expressway functionality, but also to acquire the income that supports the operation of privatized expressway companies. Therefore, we develop a multiagent simulation model consisting of the decision-making of four agents, including expressway company, highway patol company, road network users and road authority. These agents determines their schemes depending on their profit obtained. Results of the simulation identyfies the schemes that could offer the profits to the expressway companies in terms of the convenience of the users and the improvement of their operation.

  12. Multi-agent system for short and long-term power market simulations.

    SciTech Connect

    Wang, J.; Botterud, A.; Conzelmann, G.; Koritarov, V.

    2009-04-01

    In this paper we give an overview of the Electricity Market Complex Adaptive System (EMCAS) model. EMCAS uses the agent-based modeling and simulation (ABMS) technique to model the market participants in electricity markets as different agents with different strategies, risk preferences, and objectives. The complex operations of an electricity market can be simulated across several time horizons from day-ahead scheduling to long-term expansion planning. The methodology used in the model is discussed and a central European case is utilized to illustrate how EMCAS can be used to analyze a power system's operation under various assumptions. The results show the effectiveness of the model, and how the ABMS approach allows the testing of different market conditions.

  13. A rhodamine-deoxylactam based sensor for chromo-fluorogenic detection of nerve agent simulant.

    PubMed

    Wu, Zhisheng; Wu, Xuanjun; Yang, Yuhui; Wen, Ting-bin; Han, Shoufa

    2012-10-15

    N-(rhodamine B)-deoxylactam-5-amino-1-pentanol (dRB-APOH) was designed and prepared as the chromo-fluorogenic sensor for detection of a nerve agent simulant via analyte triggered tandem phosphorylation and opening of the intramolecular deoxylactam. The successful detection of diethyl chlorophosphate suggests the utility of rhodamine-deoxylactams as the chromo-fluorogenic signal reporting platform for design of sensors targeting reactive chemical species via various chemistries. PMID:22995618

  14. GridLAB-D: An Agent-Based Simulation Framework for Smart Grids

    DOE PAGESBeta

    Chassin, David P.; Fuller, Jason C.; Djilali, Ned

    2014-01-01

    Simulation of smart grid technologies requires a fundamentally new approach to integrated modeling of power systems, energy markets, building technologies, and the plethora of other resources and assets that are becoming part of modern electricity production, delivery, and consumption systems. As a result, the US Department of Energy’s Office of Electricity commissioned the development of a new type of power system simulation tool called GridLAB-D that uses an agent-based approach to simulating smart grids. This paper presents the numerical methods and approach to time-series simulation used by GridLAB-D and reviews applications in power system studies, market design, building control systemmore » design, and integration of wind power in a smart grid.« less

  15. Quantitative agent-based firm dynamics simulation with parameters estimated by financial and transaction data analysis

    NASA Astrophysics Data System (ADS)

    Ikeda, Yuichi; Souma, Wataru; Aoyama, Hideaki; Iyetomi, Hiroshi; Fujiwara, Yoshi; Kaizoji, Taisei

    2007-03-01

    Firm dynamics on a transaction network is considered from the standpoint of econophysics, agent-based simulations, and game theory. In this model, interacting firms rationally invest in a production facility to maximize net present value. We estimate parameters used in the model through empirical analysis of financial and transaction data. We propose two different methods ( analytical method and regression method) to obtain an interaction matrix of firms. On a subset of a real transaction network, we simulate firm's revenue, cost, and fixed asset, which is the accumulated investment for the production facility. The simulation reproduces the quantitative behavior of past revenues and costs within a standard error when we use the interaction matrix estimated by the regression method, in which only transaction pairs are taken into account. Furthermore, the simulation qualitatively reproduces past data of fixed assets.

  16. GridLAB-D: An Agent-Based Simulation Framework for Smart Grids

    SciTech Connect

    Chassin, David P.; Fuller, Jason C.; Djilali, Ned

    2014-06-23

    Simulation of smart grid technologies requires a fundamentally new approach to integrated modeling of power systems, energy markets, building technologies, and the plethora of other resources and assets that are becoming part of modern electricity production, delivery, and consumption systems. As a result, the US Department of Energy’s Office of Electricity commissioned the development of a new type of power system simulation tool called GridLAB-D that uses an agent-based approach to simulating smart grids. This paper presents the numerical methods and approach to time-series simulation used by GridLAB-D and reviews applications in power system studies, market design, building control system design, and integration of wind power in a smart grid.

  17. Role of coating agent in iron oxide nanoparticle formation in an aqueous dispersion: Experiments and simulation.

    PubMed

    Bachhar, Nirmalya; Bandyopadhyaya, Rajdip

    2016-02-15

    Iron oxide (Fe3O4) nanoparticle was synthesized by coprecipitation and was modeled and solved using a hybrid (discrete-continuous) model, based on a kinetic Monte Carlo (kMC) simulation scheme. The latter was combined with the constant number MC method, to improve both speed and accuracy of the simulation. Complete particle size distribution (PSD) from simulation matches very well with PSD of both uncoated and coated (with either polyacrylic acid or dextran) Fe3O4 nanoparticles, obtained from our experiments. The model is general, as the time scales of various processes (nucleation, diffusion-growth and coagulation-growth) are incorporated in rate equations, while, input simulation parameters are experimentally measured quantities. With the help of the validated model, effect of coating agent on coagulation-growth was estimated by a single, fitted, coagulation-efficiency parameter. Our simulation shows that, logarithm of coagulation-efficiency scales linearly with logarithm of inverse of the molecular weight of the coating agent. With this scaling law, our model is able to a priori predict the experimental PSD of Fe3O4 nanoparticles, synthesized with an even higher molecular weight of dextran. PMID:26624531

  18. The noncontact detection of nerve agent simulants on U.S. military CARC

    NASA Astrophysics Data System (ADS)

    Petryk, Michael W. P.

    2009-05-01

    The non-contact detection of chemical warfare agent simulants is achieved in the condensed phase using polarization modulation infrared reflection-absorption spectroscopy (PMIRRAS). The G-series nerve agent simulants, trimethyl phosphate (TMP) and triethyl phosphate (TEP), are detected on US military chemical agent resistant coating (CARC) using PMIRRAS. Optimal detector angles for PMIRRAS are determined, as are absorption features which can be used to distinguish between the spectral contributions of the substrate (CARC) and the analyte (TMP or TEP). Ab initio calculations carried out at the B3LYP / 6-31G(d,p) level of theory and basis set are used to predict the most stable simulant conformations, and their harmonic (unscaled) vibrational frequencies. Ab initio vibrational frequency data is used to explain the existence of both upward-oriented and downward-oriented PMIRRAS absorption features in terms of molecular orientation at a surface and the orientation of the dipole derivative vector of a given vibrational mode.

  19. Chemical agent simulants for testing transparent materials. Contractor report, September 1987-January 1988

    SciTech Connect

    Lewis, R.E.; Liebman, S.A.; Isaacson, L.; Grasso, P.S.; Sarver, E.W.

    1988-05-01

    Transparent polymeric materials undergo physical changes when exposed to chemical warfare agents. The object of this task was to: 1) select candidate liquids to simulate GB, VX and HD effects (three each) and 2) perform three point bend tests to determine critical strain values for cracking/crazing for simulant/transparent-polymer materials combinations. The critical-strain tests were accomplished using ASTM method D790-80 for stress crazing. The method was modified and enhanced to detect stress crazing via changes in reflection/diffraction patterns produced with a helium-neon (He-Ne) laser. Four transparent-polymer materials were tested; namely, as cast polymethyl methacrylate (PMMA), biaxially stretched PMMA, polycarbonate and polyurethane GAC-590. The critical-strain values obtained for the simulant/polymer combinations are presented as a four-by-nine map that allows easy comparisons as a function of material or simulant. Comparison with actual agent data is possible using this four-by-nine map.

  20. An Agent-Based Labor Market Simulation with Endogenous Skill-Demand

    NASA Astrophysics Data System (ADS)

    Gemkow, S.

    This paper considers an agent-based labor market simulation to examine the influence of skills on wages and unemployment rates. Therefore less and highly skilled workers as well as less and highly productive vacancies are implemented. The skill distribution is exogenous whereas the distribution of the less and highly productive vacancies is endogenous. The different opportunities of the skill groups on the labor market are established by skill requirements. This means that a highly productive vacancy can only be filled by a highly skilled unemployed. Different skill distributions, which can also be interpreted as skill-biased technological change, are simulated by incrementing the skill level of highly skilled persons exogenously. This simulation also provides a microeconomic foundation of the matching function often used in theoretical approaches.

  1. Security Analysis of Selected AMI Failure Scenarios Using Agent Based Game Theoretic Simulation

    SciTech Connect

    Abercrombie, Robert K; Schlicher, Bob G; Sheldon, Frederick T

    2014-01-01

    Information security analysis can be performed using game theory implemented in dynamic Agent Based Game Theoretic (ABGT) simulations. Such simulations can be verified with the results from game theory analysis and further used to explore larger scale, real world scenarios involving multiple attackers, defenders, and information assets. We concentrated our analysis on the Advanced Metering Infrastructure (AMI) functional domain which the National Electric Sector Cyber security Organization Resource (NESCOR) working group has currently documented 29 failure scenarios. The strategy for the game was developed by analyzing five electric sector representative failure scenarios contained in the AMI functional domain. From these five selected scenarios, we characterize them into three specific threat categories affecting confidentiality, integrity and availability (CIA). The analysis using our ABGT simulation demonstrates how to model the AMI functional domain using a set of rationalized game theoretic rules decomposed from the failure scenarios in terms of how those scenarios might impact the AMI network with respect to CIA.

  2. Model reduction for agent-based social simulation: coarse-graining a civil violence model.

    PubMed

    Zou, Yu; Fonoberov, Vladimir A; Fonoberova, Maria; Mezic, Igor; Kevrekidis, Ioannis G

    2012-06-01

    Agent-based modeling (ABM) constitutes a powerful computational tool for the exploration of phenomena involving emergent dynamic behavior in the social sciences. This paper demonstrates a computer-assisted approach that bridges the significant gap between the single-agent microscopic level and the macroscopic (coarse-grained population) level, where fundamental questions must be rationally answered and policies guiding the emergent dynamics devised. Our approach will be illustrated through an agent-based model of civil violence. This spatiotemporally varying ABM incorporates interactions between a heterogeneous population of citizens [active (insurgent), inactive, or jailed] and a population of police officers. Detailed simulations exhibit an equilibrium punctuated by periods of social upheavals. We show how to effectively reduce the agent-based dynamics to a stochastic model with only two coarse-grained degrees of freedom: the number of jailed citizens and the number of active ones. The coarse-grained model captures the ABM dynamics while drastically reducing the computation time (by a factor of approximately 20). PMID:23005161

  3. Model reduction for agent-based social simulation: Coarse-graining a civil violence model

    NASA Astrophysics Data System (ADS)

    Zou, Yu; Fonoberov, Vladimir A.; Fonoberova, Maria; Mezic, Igor; Kevrekidis, Ioannis G.

    2012-06-01

    Agent-based modeling (ABM) constitutes a powerful computational tool for the exploration of phenomena involving emergent dynamic behavior in the social sciences. This paper demonstrates a computer-assisted approach that bridges the significant gap between the single-agent microscopic level and the macroscopic (coarse-grained population) level, where fundamental questions must be rationally answered and policies guiding the emergent dynamics devised. Our approach will be illustrated through an agent-based model of civil violence. This spatiotemporally varying ABM incorporates interactions between a heterogeneous population of citizens [active (insurgent), inactive, or jailed] and a population of police officers. Detailed simulations exhibit an equilibrium punctuated by periods of social upheavals. We show how to effectively reduce the agent-based dynamics to a stochastic model with only two coarse-grained degrees of freedom: the number of jailed citizens and the number of active ones. The coarse-grained model captures the ABM dynamics while drastically reducing the computation time (by a factor of approximately 20).

  4. Parallel Agent-Based Simulations on Clusters of GPUs and Multi-Core Processors

    SciTech Connect

    Aaby, Brandon G; Perumalla, Kalyan S; Seal, Sudip K

    2010-01-01

    An effective latency-hiding mechanism is presented in the parallelization of agent-based model simulations (ABMS) with millions of agents. The mechanism is designed to accommodate the hierarchical organization as well as heterogeneity of current state-of-the-art parallel computing platforms. We use it to explore the computation vs. communication trade-off continuum available with the deep computational and memory hierarchies of extant platforms and present a novel analytical model of the tradeoff. We describe our implementation and report preliminary performance results on two distinct parallel platforms suitable for ABMS: CUDA threads on multiple, networked graphical processing units (GPUs), and pthreads on multi-core processors. Message Passing Interface (MPI) is used for inter-GPU as well as inter-socket communication on a cluster of multiple GPUs and multi-core processors. Results indicate the benefits of our latency-hiding scheme, delivering as much as over 100-fold improvement in runtime for certain benchmark ABMS application scenarios with several million agents. This speed improvement is obtained on our system that is already two to three orders of magnitude faster on one GPU than an equivalent CPU-based execution in a popular simulator in Java. Thus, the overall execution of our current work is over four orders of magnitude faster when executed on multiple GPUs.

  5. Simulation-based examination of the limits of performance for decentralized multi-agent surveillance and tracking of undersea targets

    NASA Astrophysics Data System (ADS)

    Peterson, Cameron K.; Newman, Andrew J.; Spall, James C.

    2014-06-01

    This paper examines the limits of performance for an ensemble of cooperating, mobile sensing agents executing an undersea surveillance mission. The objective of the multi-agent ensemble is to minimize uncertainty concerning the presence and location of targets as the multi-target system evolves over time. Each agent is capable of sensing, communicating with other agents, processing data to infer states of interest (fusion), and deciding on and executing motion commands. Each agent continually executes a perception-action cycle in which it fuses information to determine its best estimate of the multi-target system state and decides on its next (and possibly future) motion action(s) to optimize a criterion related to its entropic state (quantification of information gain or loss). Each agent's perception of the states of interest is derived from measurements captured by its own sensor(s) and information communicated by other agents. Each agent's decisions are based on its estimates of the multi­ target system state, its entropic state, and its predictions of peer agent actions. The multi-agent cooperative decision making can be modeled as a cyclic optimization whereby the joint decision vector is optimized by sequentially optimizing each individual agent's decision vector while holding the others fixed. Moreover, the problem is a cyclic stochastic optimization (CSO) whereby only noisy measurements of the objective function are available to each agent. Preliminary theoretical results have recently emerged regarding convergence conditions and sub-optimality for CSO. This paper examines the implications and applicability of CSO convergence and sub-optimality via simulation- based experiments in the context of a cooperating multi-agent ensemble of undersea sensing agents searching a region for new targets and maintaining track on all discovered targets. Simulation results indicate that the theoretical results provide useful guidance on predicting the empirically

  6. Graceful Failure and Societal Resilience Analysis Via Agent-Based Modeling and Simulation

    NASA Astrophysics Data System (ADS)

    Schopf, P. S.; Cioffi-Revilla, C.; Rogers, J. D.; Bassett, J.; Hailegiorgis, A. B.

    2014-12-01

    Agent-based social modeling is opening up new methodologies for the study of societal response to weather and climate hazards, and providing measures of resiliency that can be studied in many contexts, particularly in coupled human and natural-technological systems (CHANTS). Since CHANTS are complex adaptive systems, societal resiliency may or may not occur, depending on dynamics that lack closed form solutions. Agent-based modeling has been shown to provide a viable theoretical and methodological approach for analyzing and understanding disasters and societal resiliency in CHANTS. Our approach advances the science of societal resilience through computational modeling and simulation methods that complement earlier statistical and mathematical approaches. We present three case studies of social dynamics modeling that demonstrate the use of these agent based models. In Central Asia, we exmaine mutltiple ensemble simulations with varying climate statistics to see how droughts and zuds affect populations, transmission of wealth across generations, and the overall structure of the social system. In Eastern Africa, we explore how successive episodes of drought events affect the adaptive capacity of rural households. Human displacement, mainly, rural to urban migration, and livelihood transition particularly from pastoral to farming are observed as rural households interacting dynamically with the biophysical environment and continually adjust their behavior to accommodate changes in climate. In the far north case we demonstrate one of the first successful attempts to model the complete climate-permafrost-infrastructure-societal interaction network as a complex adaptive system/CHANTS implemented as a ``federated'' agent-based model using evolutionary computation. Analysis of population changes resulting from extreme weather across these and other cases provides evidence for the emergence of new steady states and shifting patterns of resilience.

  7. Agent-based model of angiogenesis simulates capillary sprout initiation in multicellular networks.

    PubMed

    Walpole, J; Chappell, J C; Cluceru, J G; Mac Gabhann, F; Bautch, V L; Peirce, S M

    2015-09-01

    Many biological processes are controlled by both deterministic and stochastic influences. However, efforts to model these systems often rely on either purely stochastic or purely rule-based methods. To better understand the balance between stochasticity and determinism in biological processes a computational approach that incorporates both influences may afford additional insight into underlying biological mechanisms that give rise to emergent system properties. We apply a combined approach to the simulation and study of angiogenesis, the growth of new blood vessels from existing networks. This complex multicellular process begins with selection of an initiating endothelial cell, or tip cell, which sprouts from the parent vessels in response to stimulation by exogenous cues. We have constructed an agent-based model of sprouting angiogenesis to evaluate endothelial cell sprout initiation frequency and location, and we have experimentally validated it using high-resolution time-lapse confocal microscopy. ABM simulations were then compared to a Monte Carlo model, revealing that purely stochastic simulations could not generate sprout locations as accurately as the rule-informed agent-based model. These findings support the use of rule-based approaches for modeling the complex mechanisms underlying sprouting angiogenesis over purely stochastic methods. PMID:26158406

  8. A Scaffolding Framework to Support Learning of Emergent Phenomena Using Multi-Agent-Based Simulation Environments

    NASA Astrophysics Data System (ADS)

    Basu, Satabdi; Sengupta, Pratim; Biswas, Gautam

    2015-04-01

    Students from middle school to college have difficulties in interpreting and understanding complex systems such as ecological phenomena. Researchers have suggested that students experience difficulties in reconciling the relationships between individuals, populations, and species, as well as the interactions between organisms and their environment in the ecosystem. Multi-agent-based computational models (MABMs) can explicitly capture agents and their interactions by representing individual actors as computational objects with assigned rules. As a result, the collective aggregate-level behavior of the population dynamically emerges from simulations that generate the aggregation of these interactions. Past studies have used a variety of scaffolds to help students learn ecological phenomena. Yet, there is no theoretical framework that supports the systematic design of scaffolds to aid students' learning in MABMs. Our paper addresses this issue by proposing a comprehensive framework for the design, analysis, and evaluation of scaffolding to support students' learning of ecology in a MABM. We present a study in which middle school students used a MABM to investigate and learn about a desert ecosystem. We identify the different types of scaffolds needed to support inquiry learning activities in this simulation environment and use our theoretical framework to demonstrate the effectiveness of our scaffolds in helping students develop a deep understanding of the complex ecological behaviors represented in the simulation..

  9. Selective opening of nanoscopic capped mesoporous inorganic materials with nerve agent simulants; an application to design chromo-fluorogenic probes.

    PubMed

    Candel, Inmaculada; Bernardos, Andrea; Climent, Estela; Marcos, M Dolores; Martínez-Máñez, Ramón; Sancenón, Félix; Soto, Juan; Costero, Ana; Gil, Salvador; Parra, Margarita

    2011-08-01

    A hybrid nanoscopic capped mesoporous material, that is selectively opened in the presence of nerve agent simulants, has been prepared and used as a probe for the chromo-fluorogenic detection of these chemicals. PMID:21691625

  10. Array of Love-wave sensors to detect CWA low-levels

    NASA Astrophysics Data System (ADS)

    Matatagui, D.; Fontecha, J.; Fernández, M. J.; Gràcia, I.; Cané, C.; Horrillo, M. C.

    2011-11-01

    Different Love-wave sensors have been developed in order to detect low-levels of chemical warfare agents for security applications. The different types of sensors have been realized using quartz and LiTaO3, as piezoelectric substrates, and SiO2 and Novolac, as guiding layers. Excellent results have been achieved with the sensors fabricated, measuring up to 200 ppb of DMMP.

  11. Scanning surface-enhanced Raman spectroscopy (SERS) of chemical agent simulants on templated Au-Ag nanowire substrates

    NASA Astrophysics Data System (ADS)

    Hoffmann, J. A.; Miragliotta, J. A.; Wang, J.; Tyagi, P.; Maddanimath, T.; Gracias, D. H.; Papadakis, S. J.

    2009-05-01

    We report the results of scanning micro-Raman spectroscopy obtained on Au-Ag nanowires for a variety of chemical warfare agent simulants. Rough silver segments embedded in gold nanowires showed enhancement of 105 - 107 and allowed unique identification of 3 of 4 chemical agent simulants tested. These results suggest a promising method for detection of compounds significant for security applications, leading to sensors that are compact and selective.

  12. Agent-Based Simulation for Interconnection-Scale Renewable Integration and Demand Response Studies

    SciTech Connect

    Chassin, David P.; Behboodi, Sahand; Crawford, Curran; Djilali, Ned

    2015-12-23

    This paper collects and synthesizes the technical requirements, implementation, and validation methods for quasi-steady agent-based simulations of interconnectionscale models with particular attention to the integration of renewable generation and controllable loads. Approaches for modeling aggregated controllable loads are presented and placed in the same control and economic modeling framework as generation resources for interconnection planning studies. Model performance is examined with system parameters that are typical for an interconnection approximately the size of the Western Electricity Coordinating Council (WECC) and a control area about 1/100 the size of the system. These results are used to demonstrate and validate the methods presented.

  13. Multi-Agent Simulations of the Immune Response to Hiv during the Acute Stage of Infection

    NASA Astrophysics Data System (ADS)

    Walshe, R.; Ruskin, H. J.; Callaghan, A.

    Results of multi-agent based simulations of the immune response to HIV during the acute phase of infection are presented here. The model successfully recreates the viral dynamics associated with the acute phase of infection, i.e., a rapid rise in viral load followed by a sharp decline to what is often referred to as a "set point", a result of T-cell response and emergence of HIV neutralizing antibodies. The results indicate that sufficient T Killer cell response is the key factor in controlling viral growth during this phase with antibody levels of critical importance only in the absence of a sufficient T Killer response.

  14. Investigation of Simulated Trading — A multi agent based trading system for optimization purposes

    NASA Astrophysics Data System (ADS)

    Schneider, Johannes J.

    2010-07-01

    Some years ago, Bachem, Hochstättler, and Malich proposed a heuristic algorithm called Simulated Trading for the optimization of vehicle routing problems. Computational agents place buy-orders and sell-orders for customers to be handled at a virtual financial market, the prices of the orders depending on the costs of inserting the customer in the tour or for his removal. According to a proposed rule set, the financial market creates a buy-and-sell graph for the various orders in the order book, intending to optimize the overall system. Here I present a thorough investigation for the application of this algorithm to the traveling salesman problem.

  15. Standoff lidar simulation for biological warfare agent detection, tracking, and classification

    NASA Astrophysics Data System (ADS)

    Jönsson, Erika; Steinvall, Ove; Gustafsson, Ove; Kullander, Fredrik; Jonsson, Per

    2010-04-01

    Lidar has been identified as a promising sensor for remote detection of biological warfare agents (BWA). Elastic IR lidar can be used for cloud detection at long ranges and UV laser induced fluorescence can be used for discrimination of BWA against naturally occurring aerosols. This paper will describe a simulation tool which enables the simulation of lidar for detection, tracking and classification of aerosol clouds. The cloud model was available from another project and has been integrated into the model. It takes into account the type of aerosol, type of release (plume or puff), amounts of BWA, winds, height above the ground and terrain roughness. The model input includes laser and receiver parameters for both the IR and UV channels as well as the optical parameters of the background, cloud and atmosphere. The wind and cloud conditions and terrain roughness are specified for the cloud simulation. The search area including the angular sampling resolution together with the IR laser pulse repetition frequency defines the search conditions. After cloud detection in the elastic mode, the cloud can be tracked using appropriate algorithms. In the tracking mode the classification using fluorescence spectral emission is simulated and tested using correlation against known spectra. Other methods for classification based on elastic backscatter are also discussed as well as the determination of particle concentration. The simulation estimates and displays the lidar response, cloud concentration as well as the goodness of fit for the classification using fluorescence.

  16. [Decontamination of chemical warfare agents by photocatalysis].

    PubMed

    Hirakawa, Tsutomu; Mera, Nobuaki; Sano, Taizo; Negishi, Nobuaki; Takeuchi, Koji

    2009-01-01

    Photocatalysis has been widely applied to solar-energy conversion and environmental purification. Photocatalyst, typically titanium dioxide (TiO(2)), produces active oxygen species under irradiation of ultraviolet light, and can decompose not only conventional pollutants but also different types of hazardous substances at mild conditions. We have recently started the study of photocatalytic decontamination of chemical warfare agents (CWAs) under collaboration with the National Research Institute of Police Science. This article reviews environmental applications of semiconductor photocatalysis, decontamination methods for CWAs, and previous photocatalytic studies applied to CWA degradation, together with some of our results obtained with CWAs and their simulant compounds. The data indicate that photocatalysis, which may not always give a striking power, certainly helps detoxification of such hazardous compounds. Unfortunately, there are not enough data obtained with real CWAs due to the difficulty in handling. We will add more scientific data using CWAs in the near future to develop useful decontamination systems that can reduce the damage caused by possible terrorism. PMID:19122438

  17. Multi-Agent-Based Simulation of a Complex Ecosystem of Mental Health Care.

    PubMed

    Kalton, Alan; Falconer, Erin; Docherty, John; Alevras, Dimitris; Brann, David; Johnson, Kyle

    2016-02-01

    This paper discusses the creation of an Agent-Based Simulation that modeled the introduction of care coordination capabilities into a complex system of care for patients with Serious and Persistent Mental Illness. The model describes the engagement between patients and the medical, social and criminal justice services they interact with in a complex ecosystem of care. We outline the challenges involved in developing the model, including process mapping and the collection and synthesis of data to support parametric estimates, and describe the controls built into the model to support analysis of potential changes to the system. We also describe the approach taken to calibrate the model to an observable level of system performance. Preliminary results from application of the simulation are provided to demonstrate how it can provide insights into potential improvements deriving from introduction of care coordination technology. PMID:26590977

  18. Promoting Conceptual Change for Complex Systems Understanding: Outcomes of an Agent-Based Participatory Simulation

    NASA Astrophysics Data System (ADS)

    Rates, Christopher A.; Mulvey, Bridget K.; Feldon, David F.

    2016-08-01

    Components of complex systems apply across multiple subject areas, and teaching these components may help students build unifying conceptual links. Students, however, often have difficulty learning these components, and limited research exists to understand what types of interventions may best help improve understanding. We investigated 32 high school students' understandings of complex systems components and whether an agent-based simulation could improve their understandings. Pretest and posttest essays were coded for changes in six components to determine whether students showed more expert thinking about the complex system of the Chesapeake Bay watershed. Results showed significant improvement for the components Emergence ( r = .26, p = .03), Order ( r = .37, p = .002), and Tradeoffs ( r = .44, p = .001). Implications include that the experiential nature of the simulation has the potential to support conceptual change for some complex systems components, presenting a promising option for complex systems instruction.

  19. AN AGENT-BASED SIMULATION STUDY OF A COMPLEX ADAPTIVE COLLABORATION NETWORK

    SciTech Connect

    Ozmen, Ozgur; Smith, Jeffrey; Yilmaz, Levent

    2013-01-01

    One of the most significant problems in organizational scholarship is to discern how social collectives govern, organize, and coordinate the actions of individuals to achieve collective outcomes. The collectives are usually interpreted as complex adaptive systems (CAS). The understanding of CAS is more likely to arise with the help of computer-based simulations. In this tutorial, using agent-based modeling approach, a complex adaptive social communication network model is introduced. The objective is to present the underlying dynamics of the system in a form of computer simulation that enables analyzing the impacts of various mechanisms on network topologies and emergent behaviors. The ultimate goal is to further our understanding of the dynamics in the system and facilitate developing informed policies for decision-makers.

  20. Promoting Conceptual Change for Complex Systems Understanding: Outcomes of an Agent-Based Participatory Simulation

    NASA Astrophysics Data System (ADS)

    Rates, Christopher A.; Mulvey, Bridget K.; Feldon, David F.

    2016-03-01

    Components of complex systems apply across multiple subject areas, and teaching these components may help students build unifying conceptual links. Students, however, often have difficulty learning these components, and limited research exists to understand what types of interventions may best help improve understanding. We investigated 32 high school students' understandings of complex systems components and whether an agent-based simulation could improve their understandings. Pretest and posttest essays were coded for changes in six components to determine whether students showed more expert thinking about the complex system of the Chesapeake Bay watershed. Results showed significant improvement for the components Emergence (r = .26, p = .03), Order (r = .37, p = .002), and Tradeoffs (r = .44, p = .001). Implications include that the experiential nature of the simulation has the potential to support conceptual change for some complex systems components, presenting a promising option for complex systems instruction.

  1. Using an agent-based model to simulate children’s active travel to school

    PubMed Central

    2013-01-01

    Background Despite the multiple advantages of active travel to school, only a small percentage of US children and adolescents walk or bicycle to school. Intervention studies are in a relatively early stage and evidence of their effectiveness over long periods is limited. The purpose of this study was to illustrate the utility of agent-based models in exploring how various policies may influence children’s active travel to school. Methods An agent-based model was developed to simulate children’s school travel behavior within a hypothetical city. The model was used to explore the plausible implications of policies targeting two established barriers to active school travel: long distance to school and traffic safety. The percent of children who walk to school was compared for various scenarios. Results To maximize the percent of children who walk to school the school locations should be evenly distributed over space and children should be assigned to the closest school. In the case of interventions to improve traffic safety, targeting a smaller area around the school with greater intensity may be more effective than targeting a larger area with less intensity. Conclusions Despite the challenges they present, agent based models are a useful complement to other analytical strategies in studying the plausible impact of various policies on active travel to school. PMID:23705953

  2. Detection of simulants and degradation products of chemical warfare agents by vibrational spectroscopy

    NASA Astrophysics Data System (ADS)

    Ruiz-Pesante, Orlando; Pacheco-Londoño, Leonardo C.; Primera-Pedrozo, Oliva M.; Ortiz, William; Soto-Feliciano, Yadira M.; Nieves, Deborah E.; Ramirez, Michael L.; Hernández-Rivera, Samuel P.

    2007-04-01

    This work was focused in the measurement of spectroscopic signatures of Chemical Warfare Agent Simulants (CWAS) and degradation products of chemical agents using vibrational spectroscopy for the generation of spectroscopic libraries. The chemicals studied were: DMMP, DIMP, 2-CEES, 2-BAET, 1,4-thioxane, thiodiglycol sulfoxide, dihexylamine, cyclohexylamine, among others. Raman microscopy experiments were performed at different excitation wavelengths that spanned from NIR at 1064 and 785 nm to the VIS at 532, 514.5 and 488 nm and even the deep ultraviolet region at 244 nm. For the compounds studied the optimum excitation lines were 488 nm and 532 nm with a laser power of 25 mW. Among the most prominent bands were at these incident wavelengths were located ca. 652 and 1444 cm-1. Fourier Transform Infrared Spectroscopy in liquid and gas phase and Fiber Optics Coupled-Grazing Angle Probe-FTIR (FOCGAP- FTIR) were used to characterize the spectroscopic signature of target threat agents. The surface experiments were performed at detection levels of about 1 μg/cm2 suggest that limits of detection (LOD) achievable could be as low as nanograms/cm2. Remote sensing experiments were performed using a telescope coupled with a Raman spectrophotometer as a function of power and acquisition time. Characterization of compounds by vibrational spectroscopy and the early stages of the transition from the lab based experiments to remote detection experiments will be presented.

  3. Modeling and simulation of virtual human's coordination based on multi-agent systems

    NASA Astrophysics Data System (ADS)

    Zhang, Mei; Wen, Jing-Hua; Zhang, Zu-Xuan; Zhang, Jian-Qing

    2006-10-01

    The difficulties and hotspots researched in current virtual geographic environment (VGE) are sharing space and multiusers operation, distributed coordination and group decision-making. The theories and technologies of MAS provide a brand-new environment for analysis, design and realization of distributed opening system. This paper takes cooperation among virtual human in VGE which multi-user participate in as main researched object. First we describe theory foundation truss of VGE, and present the formalization description of Multi-Agent System (MAS). Then we detailed analyze and research arithmetic of collectivity operating behavior learning of virtual human based on best held Genetic Algorithm(GA), and establish dynamics action model which Multi-Agents and object interact dynamically and colony movement strategy. Finally we design a example which shows how 3 evolutional Agents cooperate to complete the task of colony pushing column box, and design a virtual world prototype of virtual human pushing box collectively based on V-Realm Builder 2.0, moreover we make modeling and dynamic simulation with Simulink 6.

  4. Design and evaluation of hyperspectral algorithms for chemical warfare agent detection

    NASA Astrophysics Data System (ADS)

    Manolakis, Dimitris; D'Amico, Francis M.

    2005-11-01

    Remote sensing of chemical warfare agents (CWA) with stand-off hyperspectral imaging sensors has a wide range of civilian and military applications. These sensors exploit the spectral changes in the ambient photon flux produced by either sunlight or the thermal emission of the earth after passage through a region containing the CWA cloud. The purpose of this paper is threefold. First, to discuss a simple phenomenological model for the radiance measured by the sensor in the case of optically thin clouds. This model provides the mathematical framework for the development of optimum algorithms and their analytical evaluation. Second, we identify the fundamental aspects of the data exploitation problem and we develop detection algorithms that can be used by different sensors as long as they can provide the required measurements. Finally, we discuss performance metrics for detection, identification, and quantification and we investigate their dependance on CWA spectral signatures, sensor noise, and background spectral variability.

  5. Modeling the Information Age Combat Model: An Agent-Based Simulation of Network Centric Operations

    NASA Technical Reports Server (NTRS)

    Deller, Sean; Rabadi, Ghaith A.; Bell, Michael I.; Bowling, Shannon R.; Tolk, Andreas

    2010-01-01

    The Information Age Combat Model (IACM) was introduced by Cares in 2005 to contribute to the development of an understanding of the influence of connectivity on force effectiveness that can eventually lead to quantitative prediction and guidelines for design and employment. The structure of the IACM makes it clear that the Perron-Frobenius Eigenvalue is a quantifiable metric with which to measure the organization of a networked force. The results of recent experiments presented in Deller, et aI., (2009) indicate that the value of the Perron-Frobenius Eigenvalue is a significant measurement of the performance of an Information Age combat force. This was accomplished through the innovative use of an agent-based simulation to model the IACM and represents an initial contribution towards a new generation of combat models that are net-centric instead of using the current platform-centric approach. This paper describes the intent, challenges, design, and initial results of this agent-based simulation model.

  6. A Multi Agent-Based Framework for Simulating Household PHEV Distribution and Electric Distribution Network Impact

    SciTech Connect

    Cui, Xiaohui; Liu, Cheng; Kim, Hoe Kyoung; Kao, Shih-Chieh; Tuttle, Mark A; Bhaduri, Budhendra L

    2011-01-01

    The variation of household attributes such as income, travel distance, age, household member, and education for different residential areas may generate different market penetration rates for plug-in hybrid electric vehicle (PHEV). Residential areas with higher PHEV ownership could increase peak electric demand locally and require utilities to upgrade the electric distribution infrastructure even though the capacity of the regional power grid is under-utilized. Estimating the future PHEV ownership distribution at the residential household level can help us understand the impact of PHEV fleet on power line congestion, transformer overload and other unforeseen problems at the local residential distribution network level. It can also help utilities manage the timing of recharging demand to maximize load factors and utilization of existing distribution resources. This paper presents a multi agent-based simulation framework for 1) modeling spatial distribution of PHEV ownership at local residential household level, 2) discovering PHEV hot zones where PHEV ownership may quickly increase in the near future, and 3) estimating the impacts of the increasing PHEV ownership on the local electric distribution network with different charging strategies. In this paper, we use Knox County, TN as a case study to show the simulation results of the agent-based model (ABM) framework. However, the framework can be easily applied to other local areas in the US.

  7. An Agent-based Simulation Model for C. difficile Infection Control

    PubMed Central

    Codella, James; Safdar, Nasia; Heffernan, Rick; Alagoz, Oguzhan

    2014-01-01

    Background. Control of C. difficile infection (CDI) is an increasingly difficult problem for healthcare institutions. There are commonly recommended strategies to combat CDI transmission such as oral vancomycin for CDI treatment, increased hand hygiene with soap and water for healthcare workers, daily environmental disinfection of infected patient rooms, and contact isolation of diseased patients. However, the efficacy of these strategies, particularly for endemic CDI, has not been well studied. The objective of this research is to develop a valid agent-based simulation model (ABM) to study C. difficile transmission and control in a mid-sized hospital. Methods. We develop an ABM of a mid-sized hospital with agents such as patients, healthcare workers, and visitors. We model the natural progression of CDI in a patient using a Markov chain and the transmission of CDI through agent and environmental interactions. We derive input parameters from aggregate patient data from the 2007-2010 Wisconsin Hospital Association and published medical literature. We define a calibration process, which we use to estimate transition probabilities of the Markov model by comparing simulation results to benchmark values found in published literature. Results. Comparing CDI control strategies implemented individually, routine bleach disinfection of CDI+ patient rooms provides the largest reduction in nosocomial asymptomatic colonizations (21.8%) and nosocomial CDIs (42.8%). Additionally, vancomycin treatment provides the largest reduction in relapse CDIs (41.9%), CDI-related mortalities (68.5%), and total patient LOS (21.6%). Conclusion. We develop a generalized ABM for CDI control that can be customized and further expanded to specific institutions and/or scenarios. Additionally, we estimate transition probabilities for a Markov model of natural CDI progression in a patient through calibration. PMID:25112595

  8. An agent-based simulation model to study accountable care organizations.

    PubMed

    Liu, Pai; Wu, Shinyi

    2016-03-01

    Creating accountable care organizations (ACOs) has been widely discussed as a strategy to control rapidly rising healthcare costs and improve quality of care; however, building an effective ACO is a complex process involving multiple stakeholders (payers, providers, patients) with their own interests. Also, implementation of an ACO is costly in terms of time and money. Immature design could cause safety hazards. Therefore, there is a need for analytical model-based decision-support tools that can predict the outcomes of different strategies to facilitate ACO design and implementation. In this study, an agent-based simulation model was developed to study ACOs that considers payers, healthcare providers, and patients as agents under the shared saving payment model of care for congestive heart failure (CHF), one of the most expensive causes of sometimes preventable hospitalizations. The agent-based simulation model has identified the critical determinants for the payment model design that can motivate provider behavior changes to achieve maximum financial and quality outcomes of an ACO. The results show nonlinear provider behavior change patterns corresponding to changes in payment model designs. The outcomes vary by providers with different quality or financial priorities, and are most sensitive to the cost-effectiveness of CHF interventions that an ACO implements. This study demonstrates an increasingly important method to construct a healthcare system analytics model that can help inform health policy and healthcare management decisions. The study also points out that the likely success of an ACO is interdependent with payment model design, provider characteristics, and cost and effectiveness of healthcare interventions. PMID:24715674

  9. Real-time PCR assay for detection of a new simulant for poxvirus biothreat agents.

    PubMed

    Garnier, Laurence; Gaudin, Jean-Christophe; Bensadoun, Paul; Rebillat, Isabelle; Morel, Yannick

    2009-03-01

    Research and financial efforts spent on biodefense technologies highlight the current concern for biothreat event preparedness. Nonhazardous but relevant "simulant" microorganisms are typically used to simplify technological developments, testing, and staff training. The bacteriophage MS2, a small RNA virus, is classically used as the reference simulant for biothreat viruses within the biodefense community. However, variola virus, considered a major threat, displays very different features (size, envelope, and double-stranded DNA genome). The size parameter is critical for aerosol sampling, detection, and protection/filtration technologies. Therefore, a panel of relevant simulants should be used to cover the diversity of biothreat agents. Thus, we investigated a new virus model, the Cydia pomonella granulovirus (baculovirus), which is currently used as a biopesticide. It displays a size similar to that of poxviruses, is enveloped, and contains double-stranded DNA. To provide a molecular tool to detect and quantify this model virus, we developed an assay based on real-time PCR, with a limit of detection ranging from roughly 10 to a few tens of target copies per microl according to the sample matrix. The specificity of the assay against a large panel of potential cross-reactive microorganisms was checked, and the suitability of the assay for environmental samples, especially aerosol studies, was determined. In conclusion, we suggest that our PCR assay allows Cydia pomonella granulovirus to be used as a simulant for poxviruses. This assay may also be useful for environmental or crop treatment studies. PMID:19168659

  10. Agent-based computer simulation and sirs: building a bridge between basic science and clinical trials.

    PubMed

    An, G

    2001-10-01

    The management of Systemic Inflammatory Response Syndrome (SIRS)/Multiple Organ Failure (MOF) remains the greatest challenge in the field of critical care. There has been uniform difficulty in translating the results of basic science research into effective therapeutic regimes. We propose that this is due in part to a failure to account for the complex, nonlinear nature of the inflammatory process of which SIRS/MOF represents a disordered state. Attempts to manipulate this process without an understanding of the dynamics of the system may potentially produce unintended consequences. Agent-Based Computer Simulation (ABCS) provides a means to synthesize the information acquired from the linear analysis of basic science into a model that preserves the complexity of the inflammatory system. We have constructed an abstracted version of the inflammatory process using an ABCS that is based at the cellular level. Despite its abstraction, the simulation produces non-linear behavior and reproduces the dynamic structure of the inflammatory response. Furthermore, adjustment of the simulation to model one of the unsuccessful initial anti-inflammatory trials of the 1990's demonstrates the adverse outcome that was observed in those clinical trials. It must be emphasized that the current model is extremely abstract and simplified. However, it is hoped that future ABCSs of sufficient sophistication eventually may provide an important bridging tool to translate basic science discoveries into clinical applications. Creating these simulations will require a large collaborative effort, and it is hoped that this paper will stimulate interest in this form of analysis. PMID:11580108

  11. Decontamination Strategy for Large Area and/or Equipment Contaminated with Chemical and Biological Agents using a High Energy Arc Lamp (HEAL)

    SciTech Connect

    Schoske, Richard; Kennedy, Patrick; Duty, Chad E; Smith, Rob R; Huxford, Theodore J; Bonavita, Angelo M; Engleman, Greg; Vass, Arpad Alexander; Griest, Wayne H; Ilgner, Ralph H; Brown, Gilbert M

    2009-04-01

    A strategy for the decontamination of large areas and or equipment contaminated with Biological Warfare Agents (BWAs) and Chemical Warfare Agents (CWAs) was demonstrated using a High Energy Arc Lamp (HEAL) photolysis system. This strategy offers an alternative that is potentially quicker, less hazardous, generates far less waste, and is easier to deploy than those currently fielded by the Department of Defense (DoD). For example, for large frame aircraft the United States Air Force still relies on the combination of weathering (stand alone in environment), air washing (fly aircraft) and finally washing the aircraft with Hot Soapy Water (HSW) in an attempt to remove any remaining contamination. This method is laborious, time consuming (upwards of 12+ hours not including decontamination site preparation), and requires large amounts of water (e.g., 1,600+ gallons for a single large frame aircraft), and generates large amounts of hazardous waste requiring disposal. The efficacy of the HEAL system was demonstrated using diisopropyl methyl phosphonate (DIMP) a G series CWA simulant, and Bacillus globigii (BG) a simulant of Bacillus anthracis. Experiments were designed to simulate the energy flux of a field deployable lamp system that could stand-off 17 meters from a 12m2 target area and uniformly expose a surface at 1360 W/m2. The HEAL system in the absence of a catalyst reduced the amount of B. globigii by five orders of magnitude at a starting concentration of 1.63 x 107 spores. In the case of CWA simulants, the HEAL system in the presence of the catalyst TiO2 effectively degraded DIMP sprayed onto a 100mm diameter Petri dish in 5 minutes.

  12. CATSI EDM: recent advances in the development and validation of a ruggedized passive standoff CWA sensor

    NASA Astrophysics Data System (ADS)

    Lavoie, Hugo; Thériault, Jean-Marc; Bouffard, François; Puckrin, Eldon; Turcotte, Caroline S.; Lacasse, Paul

    2008-04-01

    Defence Research and Development Canada (DRDC) - Valcartier is currently developing a ruggedized passive standoff sensor for the detection of chemical warfare agents (CWAs) based on differential Fourier-transform infrared (FTIR) radiometry. This system is referred to as the Compact ATmospheric Sounding Interferometer (CATSI) Engineering Development Model (EDM). The CATSI EDM sensor is based on the use of a double-beam FTIR spectrometer that is optimized for optical subtraction. A description of the customized sensor is given along with a discussion on the detection and identification approaches that have been developed. Preliminary results of validation from a number of laboratory measurements and open-air trials are analyzed to establish the capability of detection and identification of various toxic and non-toxic chemical vapor plumes. These results clearly demonstrate the capability of the passive differential radiometric approach for the standoff detection and identification of chemical vapors at distances up to a few kilometers from the sensor.

  13. Evaluation of wholesale electric power market rules and financial risk management by agent-based simulations

    NASA Astrophysics Data System (ADS)

    Yu, Nanpeng

    As U.S. regional electricity markets continue to refine their market structures, designs and rules of operation in various ways, two critical issues are emerging. First, although much experience has been gained and costly and valuable lessons have been learned, there is still a lack of a systematic platform for evaluation of the impact of a new market design from both engineering and economic points of view. Second, the transition from a monopoly paradigm characterized by a guaranteed rate of return to a competitive market created various unfamiliar financial risks for various market participants, especially for the Investor Owned Utilities (IOUs) and Independent Power Producers (IPPs). This dissertation uses agent-based simulation methods to tackle the market rules evaluation and financial risk management problems. The California energy crisis in 2000-01 showed what could happen to an electricity market if it did not go through a comprehensive and rigorous testing before its implementation. Due to the complexity of the market structure, strategic interaction between the participants, and the underlying physics, it is difficult to fully evaluate the implications of potential changes to market rules. This dissertation presents a flexible and integrative method to assess market designs through agent-based simulations. Realistic simulation scenarios on a 225-bus system are constructed for evaluation of the proposed PJM-like market power mitigation rules of the California electricity market. Simulation results show that in the absence of market power mitigation, generation company (GenCo) agents facilitated by Q-learning are able to exploit the market flaws and make significantly higher profits relative to the competitive benchmark. The incorporation of PJM-like local market power mitigation rules is shown to be effective in suppressing the exercise of market power. The importance of financial risk management is exemplified by the recent financial crisis. In this

  14. Fire fighting trainers' exposure to carcinogenic agents in smoke diving simulators.

    PubMed

    Laitinen, Juha; Mäkelä, Mauri; Mikkola, Jouni; Huttu, Ismo

    2010-01-15

    It is well known that fire fighters are potentially exposed to various carcinogenic agents at a fire scene. An almost unheeded issue, however, is fire fighters' exposure to carcinogenic agents in smoke diving simulators. Biomonitoring (urinary muconic acid, 1-naphthol and 1-pyrenol), dermal (polycyclic aromatic hydrocarbons) and occupational hygiene measurements (cyanides, hydrogen cyanide, polycyclic aromatic hydrocarbons, volatile organic compounds and formaldehyde) were used to determine how the burning material, the type of simulator and protective clothing used affect fire fighting trainers' exposure. The highest excretion of 1-pyrenol (sampled 6h after end of exposure, in average 4.3-9.2nmol/L) and emissions of benzene (1.0-2.5mg/m(3)) and hydrogen cyanide (0.2-0.9mg/m(3)) were measured during the burning of conifer plywood and chipboard, and the lowest when pure pine and spruce wood (1.5nmol/L, 0.6mg/m(3), and 0.05mg/m(3)) was burned. However the safest burning material seemed to be propane (1.0nmol/L, 0.2mg/m(3), and not measured). The type of simulator used affected trainers' exposure very clearly. The highest dermal whole body exposures to polycyclic aromatic hydrocarbons were measured in the fire house simulator (in average 1200ng/cm(2)). Clearly lower exposure levels were measured in container training sessions (760ng/cm(2)), where the average dermal exposure level was 35% lower than in the fire house. The exposure levels (30ng/cm(2)) in the gas simulator in turn, were only 4% of the levels in container training sessions. The amount of polycyclic aromatic hydrocarbons decreased by 80% on trainers' hands when they used under gloves (in average 8.7ng/cm(2)) compared to those (48.4ng/cm(2)) who did not. There was not difference in protection efficiency against polycyclic aromatic hydrocarbons between tested fire suits (Brage and Bristol). PMID:19576276

  15. Agent-Based Spatiotemporal Simulation of Biomolecular Systems within the Open Source MASON Framework

    PubMed Central

    Pérez-Rodríguez, Gael; Pérez-Pérez, Martín; Glez-Peña, Daniel; Azevedo, Nuno F.; Lourenço, Anália

    2015-01-01

    Agent-based modelling is being used to represent biological systems with increasing frequency and success. This paper presents the implementation of a new tool for biomolecular reaction modelling in the open source Multiagent Simulator of Neighborhoods framework. The rationale behind this new tool is the necessity to describe interactions at the molecular level to be able to grasp emergent and meaningful biological behaviour. We are particularly interested in characterising and quantifying the various effects that facilitate biocatalysis. Enzymes may display high specificity for their substrates and this information is crucial to the engineering and optimisation of bioprocesses. Simulation results demonstrate that molecule distributions, reaction rate parameters, and structural parameters can be adjusted separately in the simulation allowing a comprehensive study of individual effects in the context of realistic cell environments. While higher percentage of collisions with occurrence of reaction increases the affinity of the enzyme to the substrate, a faster reaction (i.e., turnover number) leads to a smaller number of time steps. Slower diffusion rates and molecular crowding (physical hurdles) decrease the collision rate of reactants, hence reducing the reaction rate, as expected. Also, the random distribution of molecules affects the results significantly. PMID:25874228

  16. Multi-Agent Modeling and Simulation Approach for Design and Analysis of MER Mission Operations

    NASA Technical Reports Server (NTRS)

    Seah, Chin; Sierhuis, Maarten; Clancey, William J.

    2005-01-01

    A space mission operations system is a complex network of human organizations, information and deep-space network systems and spacecraft hardware. As in other organizations, one of the problems in mission operations is managing the relationship of the mission information systems related to how people actually work (practices). Brahms, a multi-agent modeling and simulation tool, was used to model and simulate NASA's Mars Exploration Rover (MER) mission work practice. The objective was to investigate the value of work practice modeling for mission operations design. From spring 2002 until winter 2003, a Brahms modeler participated in mission systems design sessions and operations testing for the MER mission held at Jet Propulsion Laboratory (JPL). He observed how designers interacted with the Brahms tool. This paper discussed mission system designers' reactions to the simulation output during model validation and the presentation of generated work procedures. This project spurred JPL's interest in the Brahms model, but it was never included as part of the formal mission design process. We discuss why this occurred. Subsequently, we used the MER model to develop a future mission operations concept. Team members were reluctant to use the MER model, even though it appeared to be highly relevant to their effort. We describe some of the tool issues we encountered.

  17. Detection and classification of organophosphate nerve agent simulants using support vector machines with multiarray sensors.

    PubMed

    Sadik, Omowunmi; Land, Walker H; Wanekaya, Adam K; Uematsu, Michiko; Embrechts, Mark J; Wong, Lut; Leibensperger, Dale; Volykin, Alex

    2004-01-01

    The need for rapid and accurate detection systems is expanding and the utilization of cross-reactive sensor arrays to detect chemical warfare agents in conjunction with novel computational techniques may prove to be a potential solution to this challenge. We have investigated the detection, prediction, and classification of various organophosphate (OP) nerve agent simulants using sensor arrays with a novel learning scheme known as support vector machines (SVMs). The OPs tested include parathion, malathion, dichlorvos, trichlorfon, paraoxon, and diazinon. A new data reduction software program was written in MATLAB V. 6.1 to extract steady-state and kinetic data from the sensor arrays. The program also creates training sets by mixing and randomly sorting any combination of data categories into both positive and negative cases. The resulting signals were fed into SVM software for "pairwise" and "one" vs all classification. Experimental results for this new paradigm show a significant increase in classification accuracy when compared to artificial neural networks (ANNs). Three kernels, the S2000, the polynomial, and the Gaussian radial basis function (RBF), were tested and compared to the ANN. The following measures of performance were considered in the pairwise classification: receiver operating curve (ROC) Az indices, specificities, and positive predictive values (PPVs). The ROC Az) values, specifities, and PPVs increases ranged from 5% to 25%, 108% to 204%, and 13% to 54%, respectively, in all OP pairs studied when compared to the ANN baseline. Dichlorvos, trichlorfon, and paraoxon were perfectly predicted. Positive prediction for malathion was 95%. PMID:15032529

  18. Quantitative multi-agent models for simulating protein release from PLGA bioerodible nano- and microspheres.

    PubMed

    Barat, Ana; Crane, Martin; Ruskin, Heather J

    2008-09-29

    Using poly(lactide-co-glycolide) (PLGA) particles for drug encapsulation and delivery has recently gained considerable popularity for a number of reasons. An advantage in one sense, but a drawback of PLGA use in another, is that drug delivery systems made of this material can provide a wide range of dissolution profiles, due to their internal structure and properties related to particles' manufacture. The advantages of enriching particulate drug design experimentation with computer models, are evident with simulations used to predict and optimize design, as well as indicate choice of best manufacturing parameters. In the present work, we seek to understand the phenomena observed for PLGA micro- and nanospheres, through Cellular Automata (CA) agent-based Monte Carlo (MC) models. Systems are studied both over large temporal scales (capturing slow erosion of PLGA) and for various spatial configurations (capturing initial as well as dynamic morphology). The major strength of this multi-agent approach is to observe dissolution directly, by monitoring the emergent behaviour: the dissolution profile manifested, as a sphere erodes. Different problematic aspects of the modelling process are discussed in details in this paper. The models were tested on experimental data from literature, demonstrating very good performance. Quantitative discussion is provided throughout the text in order to make a demonstration of the use in practice of the proposed model. PMID:18436414

  19. Changing crops in response to climate: virtual Nang Rong, Thailand in an agent based simulation

    PubMed Central

    Malanson, George P.; Verdery, Ashton M.; Walsh, Stephen J.; Sawangdee, Yothin; Heumann, Benjamin W.; McDaniel, Philip M.; Frizzelle, Brian G.; Williams, Nathalie E.; Yao, Xiaozheng; Entwisle, Barbara; Rindfuss, Ronald R.

    2014-01-01

    The effects of extended climatic variability on agricultural land use were explored for the type of system found in villages of northeastern Thailand. An agent based model developed for the Nang Rong district was used to simulate land allotted to jasmine rice, heavy rice, cassava, and sugar cane. The land use choices in the model depended on likely economic outcomes, but included elements of bounded rationality in dependence on household demography. The socioeconomic dynamics are endogenous in the system, and climate changes were added as exogenous drivers. Villages changed their agricultural effort in many different ways. Most villages reduced the amount of land under cultivation, primarily with reduction in jasmine rice, but others did not. The variation in responses to climate change indicates potential sensitivity to initial conditions and path dependence for this type of system. The differences between our virtual villages and the real villages of the region indicate effects of bounded rationality and limits on model applications. PMID:25061240

  20. Surface Decontamination of Simulated Chemical Warfare Agents Using a Nonequilibrium Plasma with Off-Gas Monitoring

    SciTech Connect

    Moeller, Trevor M.; Alexander, M. Lizabeth; Engelhard, Mark H.; Gaspar, Dan J.; Luna, Maria L.; Irving, Patricia M.

    2002-08-01

    InnovaTek is developing a surface decontamination technology that utilizes active species generated in a nonequilibrium corona plasma. The plasma technology was tested against DMMP, a simulant for the chemical agent Sarin. GC-MS analysis showed that a greater than four log10 destruction of the DMMP on an aluminum surface was achieved in a 10 minute treatment. An ion-trap mass spectrometer was utilized to collect time-resolved data on the treatment off-gases. These data indicate that only non-toxic fragments of the broken down DMMP molecule were present in the gas phase. The technology is being further refined to develop a product that will not only decontaminate surfaces but will also sense when decontamination is complete

  1. Gas sensor based on nano ZSM-5 zeolite films for the nerve agent simulant dimethylmethylphosphonate detection

    NASA Astrophysics Data System (ADS)

    Xie, Haifen; Ting, Yu; Sun, Xiaoxiang; Jia, Zhou; Huang, Yiping

    2004-12-01

    The piezoelectric sensor device coated with nanosize ZSM-5 zeolite films has beem fabricated. The Nerve agent simulant Dimethylmethylphosphonate has been tested with this piezoelectric sensor devices. The frequency shifts to time at 1 ppm, 5ppm and 20ppm DMMP are examined respectively. The minimum detection concentration of 1ppm DMMP has been obtained in the N2 at 293K. 1 ppm is lower than the EC50 concentration value (where EC50 is the airborne concentration sufficient to induce severe effects in 50% of those exposed for 30 min). The frequency sensitivity was found to be about 60HZ / ppm. The effect of acetone on the ZSM-5 zeolite film was also investigated for the selectivity test. Using principle component analysis (PCA), we can qualify and quantify these testing gases.

  2. Agent-Based Simulation for Interconnection-Scale Renewable Integration and Demand Response Studies

    DOE PAGESBeta

    Chassin, David P.; Behboodi, Sahand; Crawford, Curran; Djilali, Ned

    2015-12-23

    This paper collects and synthesizes the technical requirements, implementation, and validation methods for quasi-steady agent-based simulations of interconnectionscale models with particular attention to the integration of renewable generation and controllable loads. Approaches for modeling aggregated controllable loads are presented and placed in the same control and economic modeling framework as generation resources for interconnection planning studies. Model performance is examined with system parameters that are typical for an interconnection approximately the size of the Western Electricity Coordinating Council (WECC) and a control area about 1/100 the size of the system. These results are used to demonstrate and validate the methodsmore » presented.« less

  3. Prediction Markets and Beliefs about Climate: Results from Agent-Based Simulations

    NASA Astrophysics Data System (ADS)

    Gilligan, J. M.; John, N. J.; van der Linden, M.

    2015-12-01

    Climate scientists have long been frustrated by persistent doubts a large portion of the public expresses toward the scientific consensus about anthropogenic global warming. The political and ideological polarization of this doubt led Vandenbergh, Raimi, and Gilligan [1] to propose that prediction markets for climate change might influence the opinions of those who mistrust the scientific community but do trust the power of markets.We have developed an agent-based simulation of a climate prediction market in which traders buy and sell future contracts that will pay off at some future year with a value that depends on the global average temperature at that time. The traders form a heterogeneous population with different ideological positions, different beliefs about anthropogenic global warming, and different degrees of risk aversion. We also vary characteristics of the market, including the topology of social networks among the traders, the number of traders, and the completeness of the market. Traders adjust their beliefs about climate according to the gains and losses they and other traders in their social network experience. This model predicts that if global temperature is predominantly driven by greenhouse gas concentrations, prediction markets will cause traders' beliefs to converge toward correctly accepting anthropogenic warming as real. This convergence is largely independent of the structure of the market and the characteristics of the population of traders. However, it may take considerable time for beliefs to converge. Conversely, if temperature does not depend on greenhouse gases, the model predicts that traders' beliefs will not converge. We will discuss the policy-relevance of these results and more generally, the use of agent-based market simulations for policy analysis regarding climate change, seasonal agricultural weather forecasts, and other applications.[1] MP Vandenbergh, KT Raimi, & JM Gilligan. UCLA Law Rev. 61, 1962 (2014).

  4. Recent Advances in Agent-Based Tsunami Evacuation Simulations: Case Studies in Indonesia, Thailand, Japan and Peru

    NASA Astrophysics Data System (ADS)

    Mas, Erick; Koshimura, Shunichi; Imamura, Fumihiko; Suppasri, Anawat; Muhari, Abdul; Adriano, Bruno

    2015-12-01

    As confirmed by the extreme tsunami events over the last decade (the 2004 Indian Ocean, 2010 Chile and 2011 Japan tsunami events), mitigation measures and effective evacuation planning are needed to reduce disaster risks. Modeling tsunami evacuations is an alternative means to analyze evacuation plans and possible scenarios of evacuees' behaviors. In this paper, practical applications of an agent-based tsunami evacuation model are presented to demonstrate the contributions that agent-based modeling has added to tsunami evacuation simulations and tsunami mitigation efforts. A brief review of previous agent-based evacuation models in the literature is given to highlight recent progress in agent-based methods. Finally, challenges are noted for bridging gaps between geoscience and social science within the agent-based approach for modeling tsunami evacuations.

  5. Evaluating environmental strategies in a textile printing and dyeing enterprise by an agent-based simulation model

    NASA Astrophysics Data System (ADS)

    Gao, Lei; Ding, Yongsheng; Li, Fang

    2013-05-01

    To improve the capabilities of saving energy and reducing pollutant emission of textile printing and dyeing (PD) industry, this article presents a novel agent-based simulation model for assessing the impacts of environmental strategies on a PD enterprise. Two typical PD enterprises in China are simulated with different modelling granularities: one is at a module level, while the other is at an enterprise level. The module-level simulation model depicts detailed production processes in a PD enterprise and evaluates five candidate strategies on their capabilities of improving energy usage and waste emission. The enterprise-level simulation model views a PD enterprise as an agent and assesses three tax strategies for waste discharge. The simulation results show that the proposed general model could be a valuable tool to explore potential solutions to saving energy and reducing waste emission in PD enterprises, after being calibrated to a real case.

  6. An Agent-Based Simulation for Investigating the Impact of Stereotypes on Task-Oriented Group Formation

    NASA Astrophysics Data System (ADS)

    Maghami, Mahsa; Sukthankar, Gita

    In this paper, we introduce an agent-based simulation for investigating the impact of social factors on the formation and evolution of task-oriented groups. Task-oriented groups are created explicitly to perform a task, and all members derive benefits from task completion. However, even in cases when all group members act in a way that is locally optimal for task completion, social forces that have mild effects on choice of associates can have a measurable impact on task completion performance. In this paper, we show how our simulation can be used to model the impact of stereotypes on group formation. In our simulation, stereotypes are based on observable features, learned from prior experience, and only affect an agent's link formation preferences. Even without assuming stereotypes affect the agents' willingness or ability to complete tasks, the long-term modifications that stereotypes have on the agents' social network impair the agents' ability to form groups with sufficient diversity of skills, as compared to agents who form links randomly. An interesting finding is that this effect holds even in cases where stereotype preference and skill existence are completely uncorrelated.

  7. Simulation of avascular tumor growth by agent-based game model involving phenotype-phenotype interactions.

    PubMed

    Chen, Yong; Wang, Hengtong; Zhang, Jiangang; Chen, Ke; Li, Yumin

    2015-01-01

    All tumors, both benign and metastatic, undergo an avascular growth stage with nutrients supplied by the surrounding tissue. This avascular growth process is much easier to carry out in more qualitative and quantitative experiments starting from tumor spheroids in vitro with reliable reproducibility. Essentially, this tumor progression would be described as a sequence of phenotypes. Using agent-based simulation in a two-dimensional spatial lattice, we constructed a composite growth model in which the phenotypic behavior of tumor cells depends on not only the local nutrient concentration and cell count but also the game among cells. Our simulation results demonstrated that in silico tumors are qualitatively similar to those observed in tumor spheroid experiments. We also found that the payoffs in the game between two living cell phenotypes can influence the growth velocity and surface roughness of tumors at the same time. Finally, this current model is flexible and can be easily extended to discuss other situations, such as environmental heterogeneity and mutation. PMID:26648395

  8. Simulation of avascular tumor growth by agent-based game model involving phenotype-phenotype interactions

    PubMed Central

    Chen, Yong; Wang, Hengtong; Zhang, Jiangang; Chen, Ke; Li, Yumin

    2015-01-01

    All tumors, both benign and metastatic, undergo an avascular growth stage with nutrients supplied by the surrounding tissue. This avascular growth process is much easier to carry out in more qualitative and quantitative experiments starting from tumor spheroids in vitro with reliable reproducibility. Essentially, this tumor progression would be described as a sequence of phenotypes. Using agent-based simulation in a two-dimensional spatial lattice, we constructed a composite growth model in which the phenotypic behavior of tumor cells depends on not only the local nutrient concentration and cell count but also the game among cells. Our simulation results demonstrated that in silico tumors are qualitatively similar to those observed in tumor spheroid experiments. We also found that the payoffs in the game between two living cell phenotypes can influence the growth velocity and surface roughness of tumors at the same time. Finally, this current model is flexible and can be easily extended to discuss other situations, such as environmental heterogeneity and mutation. PMID:26648395

  9. The contribution of agent-based simulations to conservation management on a Natura 2000 site.

    PubMed

    Dupont, Hélène; Gourmelon, Françoise; Rouan, Mathias; Le Viol, Isabelle; Kerbiriou, Christian

    2016-03-01

    The conservation of biodiversity today must include the participation and support of local stakeholders. Natura 2000 can be considered as a conservation system that, in its application in most EU countries, relies on the participation of local stakeholders. Our study proposes a scientific method for participatory modelling, with the aim of contributing to the conservation management of habitats and species at a Natura 2000 site (Crozon Peninsula, Bretagne, France) that is representative of in landuse changes in coastal areas. We make use of companion modelling and its associated tools (scenario-planning, GIS, multi-agent modelling and simulations) to consider possible futures through the co-construction of management scenarios and the understanding of their consequences on different indicators of biodiversity status (habitats, avifauna, flora). The maintenance of human activities as they have been carried out since the creation of the Natura 2000s zone allows the biodiversity values to remain stable. Extensive agricultural activities have been shown to be essential to this maintenance, whereas management sustained by the multiplication of conservation actions brings about variable results according to the indicators. None of the scenarios has a positive incidence on the set of indicators. However, an understanding of the modelling system and the results of the simulations allow for the refining of the selection of conservation actions in relation to the species to be preserved. PMID:26696603

  10. MCNP simulation of absorbed energy and dose by iodinated contrast agent

    NASA Astrophysics Data System (ADS)

    He, Wenjun; Mah, Eugene; Huda, Walter; Yao, Hai

    2012-03-01

    The purpose of this study is to investigate the absorbed dose and energy by iodinated contrast medium in diagnostic radiology. A simulation geometry in which an inner sphere (d = 0.2cm, 1cm, 5cm) filled with iodinated contrast medium (or water) is located at the center of a 20cm diameter water sphere was used in simulations performed with MCNP5 codes. Monoenergetic x-rays with energies ranging from 40 to 80keV from a cone beam source were utilized and contrast medium concentration ranged from 100 to 1mg/ml. Absorbed dose ratio (RD) to inner sphere and total absorbed energies ratio (RE) to the whole phantom with and without iodinated contrast medium were investigated. The maximum RD was ~13 for the 0.2cm diameter sphere with 100mg/ml contrast medium. The maximum RE was ~1.05 for the 5cm diameter contrast sphere at 80keV with 100mg/ml contrast medium. Under the same incident photon energy, increasing the inner sphere size from 0.2cm to 5cm caused a ~63% increase in the RD on average. Decreasing the contrast medium concentration from 100 to 10 mg/ml caused a decrease of RD of ~ 76%. A conclusion was reached that although local absorbed dose increase caused by iodinated contrast agent could be high; the increase in total absorbed energy is negligible.

  11. An agent-based simulation of extirpation of Ceratitis capitata applied to invasions in California.

    PubMed

    Manoukis, Nicholas C; Hoffman, Kevin

    2014-01-01

    We present an agent-based simulation (ABS) of Ceratitis capitata ("Medfly") developed for estimating the time to extirpation of this pest in areas where quarantines and eradication treatments were immediately imposed. We use the ABS, implemented in the program MED-FOES, to study seven different outbreaks that occurred in Southern California from 2008 to 2010. Results are compared with the length of intervention and quarantine imposed by the State, based on a linear developmental model (thermal unit accumulation, or "degree-day"). MED-FOES is a useful tool for invasive species managers as it incorporates more information from the known biology of the Medfly, and includes the important feature of being demographically explicit, providing significant improvements over simple degree-day calculations. While there was general agreement between the length of quarantine by degree-day and the time to extirpation indicated by MED-FOES, the ABS suggests that the margin of safety varies among cases and that in two cases the quarantine may have been excessively long. We also examined changes in the number of individuals over time in MED-FOES and conducted a sensitivity analysis for one of the outbreaks to explore the role of various input parameters on simulation outcomes. While our implementation of the ABS in this work is motivated by C. capitata and takes extirpation as a postulate, the simulation is very flexible and can be used to study a variety of questions on the invasion biology of pest insects and methods proposed to manage or eradicate such species. PMID:24563646

  12. [Decontamination of chemical and biological warfare agents].

    PubMed

    Seto, Yasuo

    2009-01-01

    Chemical and biological warfare agents (CBWA's) are diverse in nature; volatile acute low-molecular-weight toxic compounds, chemical warfare agents (CWA's, gaseous choking and blood agents, volatile nerve gases and blister agents, nonvolatile vomit agents and lacrymators), biological toxins (nonvolatile low-molecular-weight toxins, proteinous toxins) and microbes (bacteria, viruses, rickettsiae). In the consequence management against chemical and biological terrorism, speedy decontamination of victims, facilities and equipment is required for the minimization of the damage. In the present situation, washing victims and contaminated materials with large volumes of water is the basic way, and additionally hypochlorite salt solution is used for decomposition of CWA's. However, it still remains unsolved how to dispose large volumes of waste water, and the decontamination reagents have serious limitation of high toxicity, despoiling nature against the environments, long finishing time and non-durability in effective decontamination. Namely, the existing decontamination system is not effective, nonspecifically affecting the surrounding non-target materials. Therefore, it is the urgent matter to build up the usable decontamination system surpassing the present technologies. The symposiast presents the on-going joint project of research and development of the novel decontamination system against CBWA's, in the purpose of realizing nontoxic, fast, specific, effective and economical terrorism on-site decontamination. The projects consists of (1) establishment of the decontamination evaluation methods and verification of the existing technologies and adaptation of bacterial organophosphorus hydrolase, (2) development of adsorptive elimination technologies using molecular recognition tools, and (4) development of deactivation technologies using photocatalysis. PMID:19122437

  13. Investigating the role of water in the Diffusion of Cholera using Agent-Based simulation

    NASA Astrophysics Data System (ADS)

    Augustijn, Ellen-Wien; Doldersum, Tom; Augustijn, Denie

    2014-05-01

    Traditionally, cholera was considered to be a waterborne disease. Currently we know that many other factors can contribute to the spread of this disease including human mobility and human behavior. However, the hydrological component in cholera diffusion is significant. The interplay between cholera and water includes bacteria (V. cholera) that survive in the aquatic environment, the possibility that run-off water from dumpsites carries the bacteria to surface water (rivers and lakes), and when the bacteria reach streams they can be carried downstream to infect new locations. Modelling is a very important tool to build theory on the interplay between different types of transmission mechanisms that together are responsible for the spread of Cholera. Agent-based simulation models are very suitable to incorporate behavior at individual level and to reproduce emergence. However, it is more difficult to incorporate the hydrological components in this type of model. In this research we present the hydrological component of an Agent-Based Cholera model developed to study a Cholera epidemic in Kumasi (Ghana) in 2005. The model was calibrated on the relative contribution of each community to the distributed pattern of cholera rather than the absolute number of incidences. Analysis of the results shows that water plays an important role in the diffusion of cholera: 75% of the cholera cases were infected via river water that was contaminated by runoff from the dumpsites. To initiate infections upstream, the probability of environment-to-human transmission seemed to be overestimated compared to what may be expected from literature. Scenario analyses show that there is a strong relation between the epidemic curve and the rainfall. Removing dumpsites that are situated close to the river resulted in a strong decrease in the number of cholera cases. Results are sensitive to the scheduling of the daily activities and the survival time of the cholera bacteria.

  14. Decontamination of chemical warfare sulfur mustard agent simulant by ZnO nanoparticles

    NASA Astrophysics Data System (ADS)

    Sadeghi, Meysam; Yekta, Sina; Ghaedi, Hamed

    2016-07-01

    In this study, zinc oxide nanoparticles (ZnO NPs) have been surveyed to decontaminate the chloroethyl phenyl sulfide as a sulfur mustard agent simulant. Prior to the reaction, ZnO NPs were successfully prepared through sol-gel method in the absence and presence of polyvinyl alcohol (PVA). PVA was utilized as a capping agent to control the agglomeration of the nanoparticles. The formation, morphology, elemental component, and crystalline size of nanoscale ZnO were certified and characterized by SEM/EDX, XRD, and FT-IR techniques. The decontamination (adsorption and destruction) was tracked by the GC-FID analysis, in which the effects of polarity of the media, such as isopropanol, acetone and n-hexane, reaction time intervals from 1 up to 18 h, and different temperatures, including 25, 35, 45, and 55 °C, on the catalytic/decontaminative capability of the surface of ZnO NPs/PVA were investigated and discussed, respectively. Results demonstrated that maximum decontamination (100 %) occurred in n-hexane solvent at 55 °C after 1 h. On the other hand, the obtained results for the acetone and isopropanol solvents were lower than expected. GC-MS chromatograms confirmed the formation of hydroxyl ethyl phenyl sulfide and phenyl vinyl sulfide as the destruction reaction products. Furthermore, these chromatograms proved the role of hydrolysis and elimination mechanisms on the catalyst considering its surface Bronsted and Lewis acid sites. A non-polar solvent aids material transfer to the reactive surface acid sites without blocking these sites.

  15. Proposal of Classification Method of Time Series Data in International Emissions Trading Market Using Agent-based Simulation

    NASA Astrophysics Data System (ADS)

    Nakada, Tomohiro; Takadama, Keiki; Watanabe, Shigeyoshi

    This paper proposes the classification method using Bayesian analytical method to classify the time series data in the international emissions trading market depend on the agent-based simulation and compares the case with Discrete Fourier transform analytical method. The purpose demonstrates the analytical methods mapping time series data such as market price. These analytical methods have revealed the following results: (1) the classification methods indicate the distance of mapping from the time series data, it is easier the understanding and inference than time series data; (2) these methods can analyze the uncertain time series data using the distance via agent-based simulation including stationary process and non-stationary process; and (3) Bayesian analytical method can show the 1% difference description of the emission reduction targets of agent.

  16. Irrigation of an established vineyard with winery cleaning agent solution (simulated winery wastewater): vine growth, berry quality, and soil chemistry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The ability to use winery wastewater (WW) for irrigation purposes could be a beneficial to the wine industry. A major difficulty in studying WW use is its inconsistent availability and composition. As such, we applied four simulated WWs composed of salts from two main industrial cleaning agents, and...

  17. Simulating the conversion of rural settlements to town land based on multi-agent systems and cellular automata.

    PubMed

    Liu, Yaolin; Kong, Xuesong; Liu, Yanfang; Chen, Yiyun

    2013-01-01

    Rapid urbanization in China has triggered the conversion of land from rural to urban use, particularly the conversion of rural settlements to town land. This conversion is the result of the joint effects of the geographic environment and agents involving the government, investors, and farmers. To understand the dynamic interaction dominated by agents and to predict the future landscape of town expansion, a small town land-planning model is proposed based on the integration of multi-agent systems (MAS) and cellular automata (CA). The MAS-CA model links the decision-making behaviors of agents with the neighbor effect of CA. The interaction rules are projected by analyzing the preference conflicts among agents. To better illustrate the effects of the geographic environment, neighborhood, and agent behavior, a comparative analysis between the CA and MAS-CA models in three different towns is presented, revealing interesting patterns in terms of quantity, spatial characteristics, and the coordinating process. The simulation of rural settlements conversion to town land through modeling agent decision and human-environment interaction is very useful for understanding the mechanisms of rural-urban land-use change in developing countries. This process can assist town planners in formulating appropriate development plans. PMID:24244472

  18. Simulating the Conversion of Rural Settlements to Town Land Based on Multi-Agent Systems and Cellular Automata

    PubMed Central

    Liu, Yaolin; Kong, Xuesong; Liu, Yanfang; Chen, Yiyun

    2013-01-01

    Rapid urbanization in China has triggered the conversion of land from rural to urban use, particularly the conversion of rural settlements to town land. This conversion is the result of the joint effects of the geographic environment and agents involving the government, investors, and farmers. To understand the dynamic interaction dominated by agents and to predict the future landscape of town expansion, a small town land-planning model is proposed based on the integration of multi-agent systems (MAS) and cellular automata (CA). The MAS-CA model links the decision-making behaviors of agents with the neighbor effect of CA. The interaction rules are projected by analyzing the preference conflicts among agents. To better illustrate the effects of the geographic environment, neighborhood, and agent behavior, a comparative analysis between the CA and MAS-CA models in three different towns is presented, revealing interesting patterns in terms of quantity, spatial characteristics, and the coordinating process. The simulation of rural settlements conversion to town land through modeling agent decision and human-environment interaction is very useful for understanding the mechanisms of rural-urban land-use change in developing countries. This process can assist town planners in formulating appropriate development plans. PMID:24244472

  19. Biophysically Realistic Filament Bending Dynamics in Agent-Based Biological Simulation

    PubMed Central

    Alberts, Jonathan B.

    2009-01-01

    An appealing tool for study of the complex biological behaviors that can emerge from networks of simple molecular interactions is an agent-based, computational simulation that explicitly tracks small-scale local interactions – following thousands to millions of states through time. For many critical cell processes (e.g. cytokinetic furrow specification, nuclear centration, cytokinesis), the flexible nature of cytoskeletal filaments is likely to be critical. Any computer model that hopes to explain the complex emergent behaviors in these processes therefore needs to encode filament flexibility in a realistic manner. Here I present a numerically convenient and biophysically realistic method for modeling cytoskeletal filament flexibility in silico. Each cytoskeletal filament is represented by a series of rigid segments linked end-to-end in series with a variable attachment point for the translational elastic element. This connection scheme allows an empirically tuning, for a wide range of segment sizes, viscosities, and time-steps, that endows any filament species with the experimentally observed (or theoretically expected) static force deflection, relaxation time-constant, and thermal writhing motions. I additionally employ a unique pair of elastic elements – one representing the axial and the other the bending rigidity– that formulate the restoring force in terms of single time-step constraint resolution. This method is highly local –adjacent rigid segments of a filament only interact with one another through constraint forces—and is thus well-suited to simulations in which arbitrary additional forces (e.g. those representing interactions of a filament with other bodies or cross-links / entanglements between filaments) may be present. Implementation in code is straightforward; Java source code is available at www.celldynamics.org. PMID:19283085

  20. Emulating a System Dynamics Model with Agent-Based Models: A Methodological Case Study in Simulation of Diabetes Progression

    SciTech Connect

    Schryver, Jack; Nutaro, James; Shankar, Mallikarjun

    2015-10-30

    An agent-based simulation model hierarchy emulating disease states and behaviors critical to progression of diabetes type 2 was designed and implemented in the DEVS framework. The models are translations of basic elements of an established system dynamics model of diabetes. In this model hierarchy, which mimics diabetes progression over an aggregated U.S. population, was dis-aggregated and reconstructed bottom-up at the individual (agent) level. Four levels of model complexity were defined in order to systematically evaluate which parameters are needed to mimic outputs of the system dynamics model. Moreover, the four estimated models attempted to replicate stock counts representing disease states in the system dynamics model, while estimating impacts of an elderliness factor, obesity factor and health-related behavioral parameters. Health-related behavior was modeled as a simple realization of the Theory of Planned Behavior, a joint function of individual attitude and diffusion of social norms that spread over each agent s social network. Although the most complex agent-based simulation model contained 31 adjustable parameters, all models were considerably less complex than the system dynamics model which required numerous time series inputs to make its predictions. In all three elaborations of the baseline model provided significantly improved fits to the output of the system dynamics model. The performances of the baseline agent-based model and its extensions illustrate a promising approach to translate complex system dynamics models into agent-based model alternatives that are both conceptually simpler and capable of capturing main effects of complex local agent-agent interactions.

  1. Emulating a System Dynamics Model with Agent-Based Models: A Methodological Case Study in Simulation of Diabetes Progression

    DOE PAGESBeta

    Schryver, Jack; Nutaro, James; Shankar, Mallikarjun

    2015-10-30

    An agent-based simulation model hierarchy emulating disease states and behaviors critical to progression of diabetes type 2 was designed and implemented in the DEVS framework. The models are translations of basic elements of an established system dynamics model of diabetes. In this model hierarchy, which mimics diabetes progression over an aggregated U.S. population, was dis-aggregated and reconstructed bottom-up at the individual (agent) level. Four levels of model complexity were defined in order to systematically evaluate which parameters are needed to mimic outputs of the system dynamics model. Moreover, the four estimated models attempted to replicate stock counts representing disease statesmore » in the system dynamics model, while estimating impacts of an elderliness factor, obesity factor and health-related behavioral parameters. Health-related behavior was modeled as a simple realization of the Theory of Planned Behavior, a joint function of individual attitude and diffusion of social norms that spread over each agent s social network. Although the most complex agent-based simulation model contained 31 adjustable parameters, all models were considerably less complex than the system dynamics model which required numerous time series inputs to make its predictions. In all three elaborations of the baseline model provided significantly improved fits to the output of the system dynamics model. The performances of the baseline agent-based model and its extensions illustrate a promising approach to translate complex system dynamics models into agent-based model alternatives that are both conceptually simpler and capable of capturing main effects of complex local agent-agent interactions.« less

  2. A spatial agent-based model for the simulation of adults' daily walking within a city.

    PubMed

    Yang, Yong; Diez Roux, Ana V; Auchincloss, Amy H; Rodriguez, Daniel A; Brown, Daniel G

    2011-03-01

    Environmental effects on walking behavior have received attention in recent years because of the potential for policy interventions to increase population levels of walking. Most epidemiologic studies describe associations of walking behavior with environmental features. These analyses ignore the dynamic processes that shape walking behaviors. A spatial agent-based model (ABM) was developed to simulate people's walking behaviors within a city. Each individual was assigned properties such as age, SES, walking ability, attitude toward walking and a home location. Individuals perform different activities on a regular basis such as traveling for work, for basic needs, and for leisure. Whether an individual walks and the amount she or he walks is a function of distance to different activities and her/his walking ability and attitude toward walking. An individual's attitude toward walking evolves over time as a function of past experiences, walking of others along the walking route, limits on distances walked per day, and attitudes toward walking of the other individuals within her/his social network. The model was calibrated and used to examine the contributions of land use and safety to socioeconomic differences in walking. With further refinement and validation, ABMs may help to better understand the determinants of walking and identify the most promising interventions to increase walking. PMID:21335269

  3. A Spatial Agent-Based Model for the Simulation of Adults’ Daily Walking Within a City

    PubMed Central

    Yang, Yong; Roux, Ana V. Diez; Auchincloss, Amy H.; Rodriguez, Daniel A.; Brown, Daniel G.

    2012-01-01

    Environmental effects on walking behavior have received attention in recent years because of the potential for policy interventions to increase population levels of walking. Most epidemiologic studies describe associations of walking behavior with environmental features. These analyses ignore the dynamic processes that shape walking behaviors. A spatial agent-based model (ABM) was developed to simulate peoples’ walking behaviors within a city. Each individual was assigned properties such as age, SES, walking ability, attitude toward walking and a home location. Individuals perform different activities on a regular basis such as traveling for work, for shopping, and for recreation. Whether an individual walks and the amount she or he walks is a function distance to different activities and her or his walking ability and attitude toward walking. An individual’s attitude toward walking evolves over time as a function of past experiences, walking of others along the walking route, limits on distances walked per day, and attitudes toward walking of the other individuals within her/his social network. The model was calibrated and used to examine the contributions of land use and safety to socioeconomic differences in walking. With further refinement and validation, ABMs may help to better understand the determinants of walking and identify the most promising interventions to increase walking. PMID:21335269

  4. Synchronisation effects on the behavioural performance and information dynamics of a simulated minimally cognitive robotic agent.

    PubMed

    Moioli, Renan C; Vargas, Patricia A; Husbands, Phil

    2012-09-01

    Oscillatory activity is ubiquitous in nervous systems, with solid evidence that synchronisation mechanisms underpin cognitive processes. Nevertheless, its informational content and relationship with behaviour are still to be fully understood. In addition, cognitive systems cannot be properly appreciated without taking into account brain-body- environment interactions. In this paper, we developed a model based on the Kuramoto Model of coupled phase oscillators to explore the role of neural synchronisation in the performance of a simulated robotic agent in two different minimally cognitive tasks. We show that there is a statistically significant difference in performance and evolvability depending on the synchronisation regime of the network. In both tasks, a combination of information flow and dynamical analyses show that networks with a definite, but not too strong, propensity for synchronisation are more able to reconfigure, to organise themselves functionally and to adapt to different behavioural conditions. The results highlight the asymmetry of information flow and its behavioural correspondence. Importantly, it also shows that neural synchronisation dynamics, when suitably flexible and reconfigurable, can generate minimally cognitive embodied behaviour. PMID:22810898

  5. Selective real-time detection of gaseous nerve agent simulants using multiwavelength photoacoustics.

    PubMed

    Gurton, Kristan P; Felton, Melvin; Tober, Richard

    2012-08-15

    An optical detection method is presented that is designed to detect and identify the presence of macromolecular gas species (e.g., organophosphate-based nerve agent simulants) at trace level concentrations. The technique is based on a modified version of conventional laser photoacoustic (PA) spectroscopy, in which optical absorption is typically measured using a single laser source. We demonstrate the ability to simultaneously measure multiple absorption-related parameters that serve as a concentration-independent identifier. Three continuous wave mid-infrared laser sources, operating at 8.68, 9.29, and 10.35 μm, are combined and propagated axially through a specially designed flow through PA cell. Each laser is modulated at a different frequency and the resultant acoustic signal(s) are detected and deconvolved using a PC-based 24 bit dynamic signal acquisition device. Species detection and identification is achieved by tabulating independent ratios of the acoustic response for each laser source. Quantitative absorption measured is verified using a Fourier transform infrared spectrometer. Results show good detection and species separation/identification at moderately low ppm concentrations. PMID:23381295

  6. Collaborative Multi-Agent Based Simulations: Stakeholder-Focused Innovation in Water Resources Management and Decision-Support Modeling

    NASA Astrophysics Data System (ADS)

    Kock, B. E.

    2006-12-01

    The combined use of multi-agent based simulations and collaborative modeling approaches is emerging as a highly effective tool for representing complex coupled social-biophysical water resource systems. A collaboratively-designed, multi-agent based simulation can be used both as a decision-support tool and as a didactic method for improving stakeholder understanding and engagement with water resources policymaking and management. Major technical and non-technical obstacles remain to the efficient and effective development of multi-agent models of human society, to integrating these models with GIS and other numerical models, and to building a process for engaging stakeholders with model design, implementation and use. It is proposed here to tackle some of these obstacles through a collaborative multi-agent based simulation process framework, intended for practical use in resolving disputes and environmental challenges over sustainable irrigated agriculture in the Western United States. A practical implementation of this framework will be conducted in collaboration with a diverse stakeholder group representing farmers and local, state and federal water managers. Through the use of simulation gaming, interviewing and computer-based knowledge elicitation, a multi-agent model representing local and regional social dynamics will be developed to support the acceptable and sustainable implementation of management alternatives for reducing regional problems of salinization and high selenium concentrations in soils and irrigation water. The development of a socially and scientifically credible simulation platform in this setting can make a significant contribution to ensuring the non-adversarial use of high quality science, enhance the engagement of stakeholders with policymaking, and help meet the challenges of integrating dynamic models of human society with more traditional biophysical systems models.

  7. An operational epidemiological model for calibrating agent-based simulations of pandemic influenza outbreaks.

    PubMed

    Prieto, D; Das, T K

    2016-03-01

    Uncertainty of pandemic influenza viruses continue to cause major preparedness challenges for public health policymakers. Decisions to mitigate influenza outbreaks often involve tradeoff between the social costs of interventions (e.g., school closure) and the cost of uncontrolled spread of the virus. To achieve a balance, policymakers must assess the impact of mitigation strategies once an outbreak begins and the virus characteristics are known. Agent-based (AB) simulation is a useful tool for building highly granular disease spread models incorporating the epidemiological features of the virus as well as the demographic and social behavioral attributes of tens of millions of affected people. Such disease spread models provide excellent basis on which various mitigation strategies can be tested, before they are adopted and implemented by the policymakers. However, to serve as a testbed for the mitigation strategies, the AB simulation models must be operational. A critical requirement for operational AB models is that they are amenable for quick and simple calibration. The calibration process works as follows: the AB model accepts information available from the field and uses those to update its parameters such that some of its outputs in turn replicate the field data. In this paper, we present our epidemiological model based calibration methodology that has a low computational complexity and is easy to interpret. Our model accepts a field estimate of the basic reproduction number, and then uses it to update (calibrate) the infection probabilities in a way that its effect combined with the effects of the given virus epidemiology, demographics, and social behavior results in an infection pattern yielding a similar value of the basic reproduction number. We evaluate the accuracy of the calibration methodology by applying it for an AB simulation model mimicking a regional outbreak in the US. The calibrated model is shown to yield infection patterns closely replicating

  8. Environmental chemistry of chemical warfare agents

    SciTech Connect

    MacNaughton, M.G.; Brewer, J.H.; Ledbetter-Ferrill, J.

    1995-06-01

    This paper summarizes the approach used in the preparation of a Handbook for the Corps of Engineers, Huntsville Division, on the environmental chemistry of chemical warfare agents. The agents GB and HD will be used to illustrate the type of information in the report. Those readers interested in the full report should contact Mr. Arkie Fanning, Huntsville Corps of Engineers at (505) 955-5256. The U.S. Army Corps of Engineers (ACE) has identified approximately 7,200 formerly used defense sites (FUDS) in the United States, some of which are suspected to be contaminated with chemical warfare agents (CWA). The ACE has responsibility for environmental clean-up of FUDS, including site characterization, evaluation and remediation of the site. Thirty-four FUDS and 48 active DOD installations that may contain CWA were identified in an Interim Survey and Analysis Report by the USACMDA Program Manager for Non-Stockpile Chemical Material (NSCM). The chemical agents listed include sulfur mustard (H), lewisite (L), tabun (GA), sarin (GB), VX, hydrogen cyanide (AC), cyanogen chloride (CK), phosgene (CG), BZ, and CS.

  9. Linking Bayesian and Agent-Based Models to Simulate Complex Social-Ecological Systems in the Sonoran Desert

    NASA Astrophysics Data System (ADS)

    Pope, A.; Gimblett, R.

    2013-12-01

    Interdependencies of ecologic, hydrologic, and social systems challenge traditional approaches to natural resource management in semi-arid regions. As a complex social-ecological system, water demands in the Sonoran Desert from agricultural and urban users often conflicts with water needs for its ecologically-significant riparian corridors. To explore this system, we developed an agent-based model to simulate complex feedbacks between human decisions and environmental conditions. Cognitive mapping in conjunction with stakeholder participation produced a Bayesian model of conditional probabilities of local human decision-making processes resulting to changes in water demand. Probabilities created in the Bayesian model were incorporated into the agent-based model, so that each agent had a unique probability to make a positive decision based on its perceived environment at each point in time and space. By using a Bayesian approach, uncertainty in the human decision-making process could be incorporated. The spatially-explicit agent-based model simulated changes in depth-to-groundwater by well pumping based on an agent's water demand. Depth-to-groundwater was then used as an indicator of unique vegetation guilds within the riparian corridor. Each vegetation guild provides varying levels of ecosystem services, the changes of which, along with changes in depth-to-groundwater, feedback to influence agent behavior. Using this modeling approach allowed us to examine resilience of semi-arid riparian corridors and agent behavior under various scenarios. The insight provided by the model contributes to understanding how specific interventions may alter the complex social-ecological system in the future.

  10. Incorporating Social Oriented Agent and Interactive Simulation in E-learning: Impact on Learning, Perceptions, Experiences to Non-Native English Students

    ERIC Educational Resources Information Center

    Ballera, Melvin; Elssaedi, Mosbah Mohamed

    2012-01-01

    There is an unrealized potential in the use of socially-oriented pedagogical agent and interactive simulation in e-learning system. In this paper, we investigate the impact of having a socially oriented tutor agent and the incorporation of interactive simulation in e-learning into student performances, perceptions and experiences for non-native…

  11. Age-correlated stress resistance improves fitness of yeast: support from agent-based simulations

    PubMed Central

    2014-01-01

    Background Resistance to stress is often heterogeneous among individuals within a population, which helps protect against intermittent stress (bet hedging). This is also the case for heat shock resistance in the budding yeast Saccharomyces cerevisiae. Interestingly, the resistance appears to be continuously distributed (vs. binary, switch-like) and correlated with replicative age (vs. random). Older, slower-growing cells are more resistant than younger, faster-growing ones. Is there a fitness benefit to age-correlated stress resistance? Results Here this hypothesis is explored using a simple agent-based model, which simulates a population of individual cells that grow and replicate. Cells age by accumulating damage, which lowers their growth rate. They synthesize trehalose at a metabolic cost, which helps protect against heat shock. Proteins Tsl1 and Tps3 (trehalose synthase complex regulatory subunit TSL1 and TPS3) represent the trehalose synthesis complex and they are expressed using constant, age-dependent and stochastic terms. The model was constrained by calibration and comparison to data from the literature, including individual-based observations obtained using high-throughput microscopy and flow cytometry. A heterogeneity network was developed, which highlights the predominant sources and pathways of resistance heterogeneity. To determine the best trehalose synthesis strategy, model strains with different Tsl1/Tps3 expression parameters were placed in competition in an environment with intermittent heat shocks. Conclusions For high severities and low frequencies of heat shock, the winning strain used an age-dependent bet hedging strategy, which shows that there can be a benefit to age-correlated stress resistance. The study also illustrates the utility of combining individual-based observations and modeling to understand mechanisms underlying population heterogeneity, and the effect on fitness. PMID:24529069

  12. Effect of Antifoam Agent on Oxidative Leaching of Hanford Tank Sludge Simulants

    SciTech Connect

    Rapko, Brian M.; Jones, Susan A.; Lumetta, Gregg J.; Peterson, Reid A.

    2010-02-26

    Oxidative leaching of simulant tank waste containing an antifoam agent (AFA) to reduce the chromium content of the sludge was tested using permanganate as the oxidant in 0.25 M NaOH solutions. AFA is added to the waste treatment process to prevent foaming. The AFA, Dow Corning Q2-3183A, is a surface-active polymer that consists of polypropylene glycol, polydimethylsiloxane, octylphenoxy polyethoxy ethanol, treated silica, and polyether polyol. Some of the Hanford Tank Waste Treatment and Immobilization Plant (WTP) waste slurries contain high concentrations of undissolved solids that would exhibit undesirable behavior without AFA addition. These tests were conducted to determine the effect of the AFA on oxidative leaching of Cr(III) in waste by permanganate. It has not previously been determined what effect AFA has on the permanganate reaction. This study was conducted to determine the effect AFA has on the oxidation of the chromium, plus plutonium and other criticality-related elements, specifically Fe, Ni and Mn. During the oxidative leaching process, Mn is added as liquid permanganate solution and is converted to an insoluble solid that precipitates as MnO2 and becomes part of the solid waste. Caustic leaching was performed followed by an oxidative leach at either 25°C or 45°C. Samples of the leachate and solids were collected at each step of the process. Initially, Battelle-Pacific Northwest Division (PNWD) was contracted by Bechtel National, Inc. to perform these further scoping studies on oxidative alkaline leaching. The data obtained from the testing will be used by the WTP operations to develop procedures for permanganate dosing of Hanford tank sludge solids during oxidative leaching. Work was initially conducted under contract number 24590-101-TSA-W000-00004. In February 2007, the contract mechanism was switched to Pacific Northwest National Laboratory (PNNL) operating Contract DE-AC05-76RL01830. In summary, this report describes work focused on

  13. Can human-like Bots control collective mood: agent-based simulations of online chats

    NASA Astrophysics Data System (ADS)

    Tadić, Bosiljka; Šuvakov, Milovan

    2013-10-01

    Using an agent-based modeling approach, in this paper, we study self-organized dynamics of interacting agents in the presence of chat Bots. Different Bots with tunable ‘human-like’ attributes, which exchange emotional messages with agents, are considered, and the collective emotional behavior of agents is quantitatively analyzed. In particular, using detrended fractal analysis we determine persistent fluctuations and temporal correlations in time series of agent activity and statistics of avalanches carrying emotional messages of agents when Bots favoring positive/negative affects are active. We determine the impact of Bots and identify parameters that can modulate that impact. Our analysis suggests that, by these measures, the emotional Bots induce collective emotion among interacting agents by suitably altering the fractal characteristics of the underlying stochastic process. Positive emotion Bots are slightly more effective than negative emotion Bots. Moreover, Bots which periodically alternate between positive and negative emotion can enhance fluctuations in the system, leading to avalanches of agent messages that are reminiscent of self-organized critical states.

  14. The application of dynamic micro-simulation model of urban planning based on multi-agent system

    NASA Astrophysics Data System (ADS)

    Xu, J.; Shiming, W.

    2012-12-01

    The dynamic micro-simulation model of urban planning based on multi-agent, is mainly used to measure and predict the impact of the policy on urban land use, employment opportunities and the price of real estate. The representation of the supply and characteristics of land and of real estate development, at a spatial scale. The use of real estate markets as a central organizing focus, with consumer choices and supplier choices explicitly represented, as well as the resulting effects on real estate prices. The relationship of agents to real estate tied to specific locations provided a clean accounting of space and its use. Finally, it will produce a map composited with the dynamic demographic distribution and the dynamic employment transfer by the geographic spatial data. With the data produced by the urban micro-simulation model, it can provide the favorable forecast reference for the scientific urban land use.

  15. Dual-Function Metal-Organic Framework as a Versatile Catalyst for Detoxifying Chemical Warfare Agent Simulants.

    PubMed

    Liu, Yangyang; Moon, Su-Young; Hupp, Joseph T; Farha, Omar K

    2015-12-22

    The nanocrystals of a porphyrin-based zirconium(IV) metal-organic framework (MOF) are used as a dual-function catalyst for the simultaneous detoxification of two chemical warfare agent simulants at room temperature. Simulants of nerve agent (such as GD, VX) and mustard gas, dimethyl 4-nitrophenyl phosphate and 2-chloroethyl ethyl sulfide, have been hydrolyzed and oxidized, respectively, to nontoxic products via a pair of pathways catalyzed by the same MOF. Phosphotriesterase-like activity of the Zr6-containing node combined with photoactivity of the porphyrin linker gives rise to a versatile MOF catalyst. In addition, bringing the MOF crystals down to the nanoregime leads to acceleration of the catalysis. PMID:26482030

  16. Simulating Land-Use Change using an Agent-Based Land Transaction Model

    NASA Astrophysics Data System (ADS)

    Bakker, M. M.; van Dijk, J.; Alam, S. J.

    2013-12-01

    In the densely populated cultural landscapes of Europe, the vast majority of all land is owned by private parties, be it farmers (the majority), nature organizations, property developers, or citizens. Therewith, the vast majority of all land-use change arises from land transactions between different owner types: successful farms expand at the expense of less successful farms, and meanwhile property developers, individual citizens, and nature organizations also actively purchase land. These land transactions are driven by specific properties of the land, by governmental policies, and by the (economic) motives of both buyers and sellers. Climate/global change can affect these drivers at various scales: at the local scale changes in hydrology can make certain land less or more desirable; at the global scale the agricultural markets will affect motives of farmers to buy or sell land; while at intermediate (e.g. provincial) scales property developers and nature conservationists may be encouraged or discouraged to purchase land. The cumulative result of all these transactions becomes manifest in changing land-use patterns, and consequent environmental responses. Within the project Climate Adaptation for Rural Areas an agent-based land-use model was developed that explores the future response of individual land users to climate change, within the context of wider global change (i.e. policy and market change). It simulates the exchange of land among farmers and between farmers and nature organizations and property developers, for a specific case study area in the east of the Netherlands. Results show that local impacts of climate change can result in a relative stagnation in the land market in waterlogged areas. Furthermore, the increase in dairying at the expense of arable cultivation - as has been observed in the area in the past - is slowing down as arable produce shows a favourable trend in the agricultural world market. Furthermore, budgets for nature managers are

  17. Multi-Agent Based Simulation of Optimal Urban Land Use Allocation in the Middle Reaches of the Yangtze River, China

    NASA Astrophysics Data System (ADS)

    Zeng, Y.; Huang, W.; Jin, W.; Li, S.

    2016-06-01

    The optimization of land-use allocation is one of important approaches to achieve regional sustainable development. This study selects Chang-Zhu-Tan agglomeration as study area and proposed a new land use optimization allocation model. Using multi-agent based simulation model, the future urban land use optimization allocation was simulated in 2020 and 2030 under three different scenarios. This kind of quantitative information about urban land use optimization allocation and urban expansions in future would be of great interest to urban planning, water and land resource management, and climate change research.

  18. Real-Time Agent-Based Modeling Simulation with in-situ Visualization of Complex Biological Systems

    PubMed Central

    Seekhao, Nuttiiya; Shung, Caroline; JaJa, Joseph; Mongeau, Luc; Li-Jessen, Nicole Y. K.

    2016-01-01

    We present an efficient and scalable scheme for implementing agent-based modeling (ABM) simulation with In Situ visualization of large complex systems on heterogeneous computing platforms. The scheme is designed to make optimal use of the resources available on a heterogeneous platform consisting of a multicore CPU and a GPU, resulting in minimal to no resource idle time. Furthermore, the scheme was implemented under a client-server paradigm that enables remote users to visualize and analyze simulation data as it is being generated at each time step of the model. Performance of a simulation case study of vocal fold inflammation and wound healing with 3.8 million agents shows 35× and 7× speedup in execution time over single-core and multi-core CPU respectively. Each iteration of the model took less than 200 ms to simulate, visualize and send the results to the client. This enables users to monitor the simulation in real-time and modify its course as needed. PMID:27547508

  19. An extensible simulation environment and movement metrics for testing walking behavior in agent-based models

    SciTech Connect

    Paul M. Torrens; Atsushi Nara; Xun Li; Haojie Zhu; William A. Griffin; Scott B. Brown

    2012-01-01

    Human movement is a significant ingredient of many social, environmental, and technical systems, yet the importance of movement is often discounted in considering systems complexity. Movement is commonly abstracted in agent-based modeling (which is perhaps the methodological vehicle for modeling complex systems), despite the influence of movement upon information exchange and adaptation in a system. In particular, agent-based models of urban pedestrians often treat movement in proxy form at the expense of faithfully treating movement behavior with realistic agency. There exists little consensus about which method is appropriate for representing movement in agent-based schemes. In this paper, we examine popularly-used methods to drive movement in agent-based models, first by introducing a methodology that can flexibly handle many representations of movement at many different scales and second, introducing a suite of tools to benchmark agent movement between models and against real-world trajectory data. We find that most popular movement schemes do a relatively poor job of representing movement, but that some schemes may well be 'good enough' for some applications. We also discuss potential avenues for improving the representation of movement in agent-based frameworks.

  20. Integrating the simulation of domestic water demand behaviour to an urban water model using agent based modelling

    NASA Astrophysics Data System (ADS)

    Koutiva, Ifigeneia; Makropoulos, Christos

    2015-04-01

    The urban water system's sustainable evolution requires tools that can analyse and simulate the complete cycle including both physical and cultural environments. One of the main challenges, in this regard, is the design and development of tools that are able to simulate the society's water demand behaviour and the way policy measures affect it. The effects of these policy measures are a function of personal opinions that subsequently lead to the formation of people's attitudes. These attitudes will eventually form behaviours. This work presents the design of an ABM tool for addressing the social dimension of the urban water system. The created tool, called Urban Water Agents' Behaviour (UWAB) model, was implemented, using the NetLogo agent programming language. The main aim of the UWAB model is to capture the effects of policies and environmental pressures to water conservation behaviour of urban households. The model consists of agents representing urban households that are linked to each other creating a social network that influences the water conservation behaviour of its members. Household agents are influenced as well by policies and environmental pressures, such as drought. The UWAB model simulates behaviour resulting in the evolution of water conservation within an urban population. The final outcome of the model is the evolution of the distribution of different conservation levels (no, low, high) to the selected urban population. In addition, UWAB is implemented in combination with an existing urban water management simulation tool, the Urban Water Optioneering Tool (UWOT) in order to create a modelling platform aiming to facilitate an adaptive approach of water resources management. For the purposes of this proposed modelling platform, UWOT is used in a twofold manner: (1) to simulate domestic water demand evolution and (2) to simulate the response of the water system to the domestic water demand evolution. The main advantage of the UWAB - UWOT model

  1. Coupling multi-agent model and GIS to simulate pine wood nematode disease spread in ZheJiang Province, China

    NASA Astrophysics Data System (ADS)

    Huang, Huaguo; Wang, Lei; Zhang, XiaoLi; Luo, YouQing; Zhao, Liqiong

    2008-10-01

    A coupled method based on multi-agent model, remote sensing and GIS is described to simulate the forest disease spread. The coupled model focuses on the temporal dynamics of the Bursaphelenchus xylophilus population at the landscape scale. Each individual is modeled as an autonomous agent who behaves according to a set of rules including spreading in the landscape, feeding on Pinus massoniana, sheltering in forest edges and dying, constrained by terrain, land cover and other variables. The model parameters are derived from remote sensing data and field measurements. Ten factors, including damage degree of Pinus Massoniana, altitude and slope, are helped to build the transfer rules. The main outputs are the dynamic disease distribution maps and survived pine population. Our method is applied and validated in DingHai distinct, Zhou Shan city of Zhejiang Province. Three Landsat TM images from the year 1991 to 2006 are used for the pine information extraction. The extracted pine distribution map is used to compare with the simulated surviving pine map. The results show that the coupled model can produce reasonable results and be used as a virtual experiment tool. However, it is difficult to simulate the human activities to help or prevent disease spread and the long fly behavior of insect vectors. Therefore, there still exists some difference between the simulated results and the real data. At the next step, those factors will be considered.

  2. Using the Integration of Discrete Event and Agent-Based Simulation to Enhance Outpatient Service Quality in an Orthopedic Department.

    PubMed

    Kittipittayakorn, Cholada; Ying, Kuo-Ching

    2016-01-01

    Many hospitals are currently paying more attention to patient satisfaction since it is an important service quality index. Many Asian countries' healthcare systems have a mixed-type registration, accepting both walk-in patients and scheduled patients. This complex registration system causes a long patient waiting time in outpatient clinics. Different approaches have been proposed to reduce the waiting time. This study uses the integration of discrete event simulation (DES) and agent-based simulation (ABS) to improve patient waiting time and is the first attempt to apply this approach to solve this key problem faced by orthopedic departments. From the data collected, patient behaviors are modeled and incorporated into a massive agent-based simulation. The proposed approach is an aid for analyzing and modifying orthopedic department processes, allows us to consider far more details, and provides more reliable results. After applying the proposed approach, the total waiting time of the orthopedic department fell from 1246.39 minutes to 847.21 minutes. Thus, using the correct simulation model significantly reduces patient waiting time in an orthopedic department. PMID:27195606

  3. Applying GIS and high performance agent-based simulation for managing an Old World Screwworm fly invasion of Australia.

    PubMed

    Welch, M C; Kwan, P W; Sajeev, A S M

    2014-10-01

    Agent-based modelling has proven to be a promising approach for developing rich simulations for complex phenomena that provide decision support functions across a broad range of areas including biological, social and agricultural sciences. This paper demonstrates how high performance computing technologies, namely General-Purpose Computing on Graphics Processing Units (GPGPU), and commercial Geographic Information Systems (GIS) can be applied to develop a national scale, agent-based simulation of an incursion of Old World Screwworm fly (OWS fly) into the Australian mainland. The development of this simulation model leverages the combination of massively data-parallel processing capabilities supported by NVidia's Compute Unified Device Architecture (CUDA) and the advanced spatial visualisation capabilities of GIS. These technologies have enabled the implementation of an individual-based, stochastic lifecycle and dispersal algorithm for the OWS fly invasion. The simulation model draws upon a wide range of biological data as input to stochastically determine the reproduction and survival of the OWS fly through the different stages of its lifecycle and dispersal of gravid females. Through this model, a highly efficient computational platform has been developed for studying the effectiveness of control and mitigation strategies and their associated economic impact on livestock industries can be materialised. PMID:24705073

  4. Research on the interaction of hydrogen-bond acidic polymer sensitive sensor materials with chemical warfare agents simulants by inverse gas chromatography.

    PubMed

    Yang, Liu; Han, Qiang; Cao, Shuya; Huang, Feng; Qin, Molin; Guo, Chenghai; Ding, Mingyu

    2015-01-01

    Hydrogen-bond acidic polymers are important high affinity materials sensitive to organophosphates in the chemical warfare agent sensor detection process. Interactions between the sensor sensitive materials and chemical warfare agent simulants were studied by inverse gas chromatography. Hydrogen bonded acidic polymers, i.e., BSP3, were prepared for micro-packed columns to examine the interaction. DMMP (a nerve gas simulant) and 2-CEES (a blister agent simulant) were used as probes. Chemical and physical parameters such as heats of absorption and Henry constants of the polymers to DMMP and 2-CEES were determined by inverse gas chromatography. Details concerning absorption performance are also discussed in this paper. PMID:26043177

  5. Research on the Interaction of Hydrogen-Bond Acidic Polymer Sensitive Sensor Materials with Chemical Warfare Agents Simulants by Inverse Gas Chromatography

    PubMed Central

    Yang, Liu; Han, Qiang; Cao, Shuya; Huang, Feng; Qin, Molin; Guo, Chenghai; Ding, Mingyu

    2015-01-01

    Hydrogen-bond acidic polymers are important high affinity materials sensitive to organophosphates in the chemical warfare agent sensor detection process. Interactions between the sensor sensitive materials and chemical warfare agent simulants were studied by inverse gas chromatography. Hydrogen bonded acidic polymers, i.e., BSP3, were prepared for micro-packed columns to examine the interaction. DMMP (a nerve gas simulant) and 2-CEES (a blister agent simulant) were used as probes. Chemical and physical parameters such as heats of absorption and Henry constants of the polymers to DMMP and 2-CEES were determined by inverse gas chromatography. Details concerning absorption performance are also discussed in this paper. PMID:26043177

  6. Determination of trace amounts of chemical warfare agent degradation products in decontamination solutions with NMR spectroscopy.

    PubMed

    Koskela, Harri; Rapinoja, Marja-Leena; Kuitunen, Marja-Leena; Vanninen, Paula

    2007-12-01

    Decontamination solutions are used for an efficient detoxification of chemical warfare agents (CWAs). As these solutions can be composed of strong alkaline chemicals with hydrolyzing and oxidizing properties, the analysis of CWA degradation products in trace levels from these solutions imposes a challenge for any analytical technique. Here, we present results of application of nuclear magnetic resonance spectroscopy for analysis of trace amounts of CWA degradation products in several untreated decontamination solutions. Degradation products of the nerve agents sarin, soman, and VX were selectively monitored with substantially reduced interference of background signals by 1D 1H-31P heteronuclear single quantum coherence (HSQC) spectrometry. The detection limit of the chemicals was at the low part-per-million level (2-10 microg/mL) in all studied solutions. In addition, the concentration of the degradation products was obtained with sufficient confidence with external standards. PMID:17973498

  7. Impact of Different Policies on Unhealthy Dietary Behaviors in an Urban Adult Population: An Agent-Based Simulation Model

    PubMed Central

    Giabbanelli, Philippe J.; Arah, Onyebuchi A.; Zimmerman, Frederick J.

    2014-01-01

    Objectives. Unhealthy eating is a complex-system problem. We used agent-based modeling to examine the effects of different policies on unhealthy eating behaviors. Methods. We developed an agent-based simulation model to represent a synthetic population of adults in Pasadena, CA, and how they make dietary decisions. Data from the 2007 Food Attitudes and Behaviors Survey and other empirical studies were used to calibrate the parameters of the model. Simulations were performed to contrast the potential effects of various policies on the evolution of dietary decisions. Results. Our model showed that a 20% increase in taxes on fast foods would lower the probability of fast-food consumption by 3 percentage points, whereas improving the visibility of positive social norms by 10%, either through community-based or mass-media campaigns, could improve the consumption of fruits and vegetables by 7 percentage points and lower fast-food consumption by 6 percentage points. Zoning policies had no significant impact. Conclusions. Interventions emphasizing healthy eating norms may be more effective than directly targeting food prices or regulating local food outlets. Agent-based modeling may be a useful tool for testing the population-level effects of various policies within complex systems. PMID:24832414

  8. Review of environmental exposure concentrations of chemical warfare agent residues and associated the fish community risk following the construction and completion of the Nord Stream gas pipeline between Russia and Germany.

    PubMed

    Sanderson, Hans; Fauser, Patrik; Rahbek, Malene; Larsen, Jørn Bo

    2014-08-30

    This paper compiles all the measured chemical warfare agent (CWA) concentrations found in relation to the Nord Stream pipeline work in Danish waters for the past 5 years. Sediment and biota sampling were performed along the pipeline route in four campaigns, prior to (in 2008 and 2010), during (in 2011) and after (in 2012) the construction work. No parent CWAs were detected in the sediments. Patchy residues of CWA degradation products of Adamsite, Clark I, phenyldichloroarsine, trichloroarsine and Lewisite II, were detected in a total of 29 of the 391 sediment samples collected and analyzed the past 5 years. The cumulative fish community risk quotient for the different locations, calculated as a sum of background and added risk, ranged between 0 and 0.017 suggesting a negligible acute CWA risk toward the fish community. The added risk from sediment disturbance in relation to construction of the pipelines represents less than 2% of the total risk in the areas with the highest calculated risk. The analyses of benthic infauna corroborate the finding of CWA related low risk across the years. There was no significant difference in CWA risk before (2008) and after the pipeline construction (2012). PMID:25113514

  9. Multi-agent Simulation about Urban Dynamics Based on a Hypothetical Relationship between Individuals' Travel Behavior and Residential Choice Behavior

    NASA Astrophysics Data System (ADS)

    Taniguchi, Tadahiro; Takahashi, Yusuke

    In this paper, we proposed a simple urban model including individuals' travel behavior and residential choice behavior. Multi-agent simulation framework is described. We performed several experiments to evaluate political measures which will solve problems about motorization. As a result, drastic mobility management scheme increased the number of travelers using a train, and the distribution of residences became compact. However, it also increased many agents' total costs of living because of high rent and several kinds of cost including time cost and fatigue cost to reach a station. On the other hand, raising gas price made CO2 emission less and kept total cost of living lower than the drastic mobility management measure. This suggests that to have people use train or bus by changing their attitude might be socially more expensive than to make people chose whether they use car or not under the condition that gas price is raised.

  10. A cyclization-induced emission enhancement (CIEE)-based ratiometric fluorogenic and chromogenic probe for the facile detection of a nerve agent simulant DCP.

    PubMed

    Mahapatra, Ajit Kumar; Maiti, Kalipada; Manna, Saikat Kumar; Maji, Rajkishor; Mondal, Sanchita; Das Mukhopadhyay, Chitrangada; Sahoo, Prithidipa; Mandal, Debasish

    2015-06-14

    The first ratiometric fluorescent probe for the detection of a nerve agent simulant was developed based on tandem phosphorylation and intramolecular cyclization, by which high sensitivity as well as large emission shift could be achieved. PMID:25980383

  11. Simulated experiment for elimination of air contaminated with odorous chemical agents by microwave plasma burner

    SciTech Connect

    Hong, Yong Cheol; Shin, Dong Hun; Uhm, Han Sup

    2007-10-15

    An experimental study on elimination of odorous chemical agent was carried out by making use of a microwave plasma burner, which consists of a microwave plasma torch and a reaction chamber with a fuel injector. Injection of hydrocarbon fuels into a high-temperature microwave torch plasma generates a plasma flame. The plasma flame can eliminate the odorous chemical agent diluted in air or purify the interior air of a large volume in isolated spaces. The specially designed reaction chamber eliminated H{sub 2}S and NH{sub 3} diluted in airflow rate of 5000 lpm (liters per minute), showing {beta} values of 46.52 and 39.69 J/l, respectively.

  12. Highly selective detection of nerve-agent simulants with BODIPY dyes.

    PubMed

    Barba-Bon, Andrea; Costero, Ana M; Gil, Salvador; Harriman, Anthony; Sancenón, Félix

    2014-05-19

    Two chromo-fluorogenic probes, each based on the boron dipyrromethene core, have been developed for the detection of nerve-agent mimics. These chemosensors display both a color change and a significant enhancement of fluorescence in the presence of diethylcyanophosphonate (DCNP) and diisopropylfluorophosphate (DFP). No interference from other organophosphorus compounds or acids has been observed. Two portable chemosensor kits have been developed and tested to demonstrate its practical application in real-time monitoring. PMID:24700454

  13. Distribution of chemical warfare agent, energetics, and metals in sediments at a deep-water discarded military munitions site

    NASA Astrophysics Data System (ADS)

    Briggs, Christian; Shjegstad, Sonia M.; Silva, Jeff A. K.; Edwards, Margo H.

    2016-06-01

    There is a strong need to understand the behavior of chemical warfare agent (CWA) at underwater discarded military munitions (DMM) sites to determine the potential threat to human health or the environment, yet few studies have been conducted at sites in excess of 250 m, the depth at which most U.S. chemical munitions were disposed. As part of the Hawai'i Undersea Military Munitions Assessment (HUMMA), sediments adjacent to chemical and conventional DMM at depths of 400-650 m were sampled using human occupied vehicles (HOVs) in order to quantify the distribution of CWA, energetics, and select metals. Sites in the same general area, with no munitions within 50 m in any direction were sampled as a control. Sulfur mustard (HD) and its degradation product 1,4-dithiane were detected at each CWA DMM site, as well as a single sample with the HD degradation product 1,4-thioxane. An energetic compound was detected in sediment to a limited extent at one CWA DMM site. Metals common in munitions casings (i.e., Fe, Cu, and Pb) showed similar trends at the regional and site-wide scales, likely reflecting changes in marine sediment deposition and composition. This study shows HD and its degradation products can persist in the deep-marine environment for decades following munitions disposal.

  14. Identification of vapor-phase chemical warfare agent simulants and rocket fuels using laser-induced breakdown spectroscopy

    SciTech Connect

    Stearns, Jaime A.; McElman, Sarah E.; Dodd, James A.

    2010-05-01

    Application of laser-induced breakdown spectroscopy (LIBS) to the identification of security threats is a growing area of research. This work presents LIBS spectra of vapor-phase chemical warfare agent simulants and typical rocket fuels. A large dataset of spectra was acquired using a variety of gas mixtures and background pressures and processed using partial least squares analysis. The five compounds studied were identified with a 99% success rate by the best method. The temporal behavior of the emission lines as a function of chamber pressure and gas mixture was also investigated, revealing some interesting trends that merit further study.

  15. Antioxidants as potential medical countermeasures for chemical warfare agents and toxic industrial chemicals.

    PubMed

    McElroy, Cameron S; Day, Brian J

    2016-01-15

    The continuing horrors of military conflicts and terrorism often involve the use of chemical warfare agents (CWAs) and toxic industrial chemicals (TICs). Many CWA and TIC exposures are difficult to treat due to the danger they pose to first responders and their rapid onset that can produce death shortly after exposure. While the specific mechanism(s) of toxicity of these agents are diverse, many are associated either directly or indirectly with increased oxidative stress in affected tissues. This has led to the exploration of various antioxidants as potential medical countermeasures for CWA/TIC exposures. Studies have been performed across a wide array of agents, model organisms, exposure systems, and antioxidants, looking at an almost equally diverse set of endpoints. Attempts at treating CWAs/TICs with antioxidants have met with mixed results, ranging from no effect to nearly complete protection. The aim of this commentary is to summarize the literature in each category for evidence of oxidative stress and antioxidant efficacy against CWAs and TICs. While there is great disparity in the data concerning methods, models, and remedies, the outlook on antioxidants as medical countermeasures for CWA/TIC management appears promising. PMID:26476351

  16. An agent-based framework for fuel cycle simulation with recycling

    SciTech Connect

    Gidden, M.J.; Wilson, P.P.H.; Huff, K.D.; Carlsen, R.W.

    2013-07-01

    Simulation of the nuclear fuel cycle is an established field with multiple players. Prior development work has utilized techniques such as system dynamics to provide a solution structure for the matching of supply and demand in these simulations. In general, however, simulation infrastructure development has occurred in relatively closed circles, each effort having unique considerations as to the cases which are desired to be modeled. Accordingly, individual simulators tend to have their design decisions driven by specific use cases. Presented in this work is a proposed supply and demand matching algorithm that leverages the techniques of the well-studied field of mathematical programming. A generic approach is achieved by treating facilities as individual entities and actors in the supply-demand market which denote preferences amongst commodities. Using such a framework allows for varying levels of interaction fidelity, ranging from low-fidelity, quick solutions to high-fidelity solutions that model individual transactions (e.g. at the fuel-assembly level). The power of the technique is that it allows such flexibility while still treating the problem in a generic manner, encapsulating simulation engine design decisions in such a way that future simulation requirements can be relatively easily added when needed. (authors)

  17. Understanding coupled natural and human systems on fire prone landscapes: integrating wildfire simulation into an agent based planning system.

    NASA Astrophysics Data System (ADS)

    Barros, Ana; Ager, Alan; Preisler, Haiganoush; Day, Michelle; Spies, Tom; Bolte, John

    2015-04-01

    Agent-based models (ABM) allow users to examine the long-term effects of agent decisions in complex systems where multiple agents and processes interact. This framework has potential application to study the dynamics of coupled natural and human systems where multiple stimuli determine trajectories over both space and time. We used Envision, a landscape based ABM, to analyze long-term wildfire dynamics in a heterogeneous, multi-owner landscape in Oregon, USA. Landscape dynamics are affected by land management policies, actors decisions, and autonomous processes such as vegetation succession, wildfire, or at a broader scale, climate change. Key questions include: 1) How are landscape dynamics influenced by policies and institutions, and 2) How do land management policies and actor decisions interact to produce intended and unintended consequences with respect to wildfire on fire-prone landscapes. Applying Envision to address these questions required the development of a wildfire module that could accurately simulate wildfires on the heterogeneous landscapes within the study area in terms of replicating historical fire size distribution, spatial distribution and fire intensity. In this paper we describe the development and testing of a mechanistic fire simulation system within Envision and application of the model on a 3.2 million fire prone landscape in central Oregon USA. The core fire spread equations use the Minimum Travel Time algorithm developed by M Finney. The model operates on a daily time step and uses a fire prediction system based on the relationship between energy release component and historical fires. Specifically, daily wildfire probabilities and sizes are generated from statistical analyses of historical fires in relation to daily ERC values. The MTT was coupled with the vegetation dynamics module in Envision to allow communication between the respective subsystem and effectively model fire effects and vegetation dynamics after a wildfire. Canopy and

  18. Spectroscopic investigation of the noncovalent association of the nerve agent simulant diisopropyl methylphosphonate (DIMP) with zinc(II) porphyrins.

    PubMed

    Maza, William A; Vetromile, Carissa M; Kim, Chungsik; Xu, Xue; Zhang, X Peter; Larsen, Randy W

    2013-11-01

    Organophosphonates pose a significant threat as chemical warfare agents, as well as environmental toxins in the form of pesticides. Thus, methodologies to sense and decontaminate these agents are of significant interest. Porphyrins and metalloporphyrins offer an excellent platform to develop chemical threat sensors and photochemical degradation systems. These highly conjugated planar molecules exhibit relatively long-lived singlet and triplet states with high quantum yields and also form self-associated complexes with a wide variety of molecules. A significant aspect of porphyrins is the ability to functionalize the peripheral ring system either directly to the pyrrole rings or to the bridging methine carbons. In this report, steady-state absorption and fluorescence are utilized to probe binding affinities of a series of symmetric and asymmetric zinc(II) metalloporphyrins for the nerve agent simulant diisopropyl methylphosphonate (DIMP) in hexane. The red shifts in the absorption and emission spectra observed for all of the metalloporphyrins probed are discussed in the frame of Gouterman's four orbital model and a common binding motif involving coordination between the metalloporphyrin and DIMP via interaction between the zinc metal center of the porphyrin and phosphoryl oxygen of DIMP (Zn-O═P) is proposed. PMID:24093669

  19. Agent-based Modeling to Simulate the Diffusion of Water-Efficient Innovations and the Emergence of Urban Water Sustainability

    NASA Astrophysics Data System (ADS)

    Kanta, L.; Giacomoni, M.; Shafiee, M. E.; Berglund, E.

    2014-12-01

    The sustainability of water resources is threatened by urbanization, as increasing demands deplete water availability, and changes to the landscape alter runoff and the flow regime of receiving water bodies. Utility managers typically manage urban water resources through the use of centralized solutions, such as large reservoirs, which may be limited in their ability balance the needs of urbanization and ecological systems. Decentralized technologies, on the other hand, may improve the health of the water resources system and deliver urban water services. For example, low impact development technologies, such as rainwater harvesting, and water-efficient technologies, such as low-flow faucets and toilets, may be adopted by households to retain rainwater and reduce demands, offsetting the need for new centralized infrastructure. Decentralized technologies may create new complexities in infrastructure and water management, as decentralization depends on community behavior and participation beyond traditional water resources planning. Messages about water shortages and water quality from peers and the water utility managers can influence the adoption of new technologies. As a result, feedbacks between consumers and water resources emerge, creating a complex system. This research develops a framework to simulate the diffusion of water-efficient innovations and the sustainability of urban water resources, by coupling models of households in a community, hydrologic models of a water resources system, and a cellular automata model of land use change. Agent-based models are developed to simulate the land use and water demand decisions of individual households, and behavioral rules are encoded to simulate communication with other agents and adoption of decentralized technologies, using a model of the diffusion of innovation. The framework is applied for an illustrative case study to simulate water resources sustainability over a long-term planning horizon.

  20. The Basic Immune Simulator: An agent-based model to study the interactions between innate and adaptive immunity

    PubMed Central

    Folcik, Virginia A; An, Gary C; Orosz, Charles G

    2007-01-01

    Background We introduce the Basic Immune Simulator (BIS), an agent-based model created to study the interactions between the cells of the innate and adaptive immune system. Innate immunity, the initial host response to a pathogen, generally precedes adaptive immunity, which generates immune memory for an antigen. The BIS simulates basic cell types, mediators and antibodies, and consists of three virtual spaces representing parenchymal tissue, secondary lymphoid tissue and the lymphatic/humoral circulation. The BIS includes a Graphical User Interface (GUI) to facilitate its use as an educational and research tool. Results The BIS was used to qualitatively examine the innate and adaptive interactions of the immune response to a viral infection. Calibration was accomplished via a parameter sweep of initial agent population size, and comparison of simulation patterns to those reported in the basic science literature. The BIS demonstrated that the degree of the initial innate response was a crucial determinant for an appropriate adaptive response. Deficiency or excess in innate immunity resulted in excessive proliferation of adaptive immune cells. Deficiency in any of the immune system components increased the probability of failure to clear the simulated viral infection. Conclusion The behavior of the BIS matches both normal and pathological behavior patterns in a generic viral infection scenario. Thus, the BIS effectively translates mechanistic cellular and molecular knowledge regarding the innate and adaptive immune response and reproduces the immune system's complex behavioral patterns. The BIS can be used both as an educational tool to demonstrate the emergence of these patterns and as a research tool to systematically identify potential targets for more effective treatment strategies for diseases processes including hypersensitivity reactions (allergies, asthma), autoimmunity and cancer. We believe that the BIS can be a useful addition to the growing suite of in

  1. Mathematical Simulation of the Extraction of a Blending Agent from Cylindrical Bodies in the Semicontinuous Regime

    NASA Astrophysics Data System (ADS)

    Rudobashta, S. P.; Kosheleva, M. K.; Kartashov, É. M.

    2016-06-01

    A problem of the kinetics of extraction of a blending agent from cylindrical bodies in an apparatus of semicontinuous action (periodic for the solid phase and continuous for the liquid phase) in which the liquid phase is completely mixed was formulated and solved analytically. The kinetics of the indicated process at different specific flow rates of the liquid phase was analyzed with the use of a numerical method. Recommendations on the use of the solution obtained for calculating the kinetics of extraction of technological contaminants from textile materials in the process of their flushing are given

  2. Mathematical Simulation of the Extraction of a Blending Agent from Cylindrical Bodies in the Semicontinuous Regime

    NASA Astrophysics Data System (ADS)

    Rudobashta, S. P.; Kosheleva, M. K.; Kartashov, É. M.

    2016-05-01

    A problem of the kinetics of extraction of a blending agent from cylindrical bodies in an apparatus of semicontinuous action (periodic for the solid phase and continuous for the liquid phase) in which the liquid phase is completely mixed was formulated and solved analytically. The kinetics of the indicated process at different specific flow rates of the liquid phase was analyzed with the use of a numerical method. Recommendations on the use of the solution obtained for calculating the kinetics of extraction of technological contaminants from textile materials in the process of their flushing are given

  3. Non-contact detection of chemical warfare simulant triethyl phosphate using PM-IRRAS.

    PubMed

    Kycia, Annia H; Vezvaie, Mansoor; Zamlynny, Vlad; Lipkowski, Jacek; Petryk, Michael W P

    2012-08-01

    Polarization modulation-infrared reflection absorption spectroscopy (PM-IRRAS) was employed to detect the chemical warfare agent (CWA) simulant triethyl phosphate (TEP) on gold, as well as on US military paint, i.e., chemical agent resistant coating (CARC). The targeted CWAs (G and V-series nerve agents) are characterized by phosphoric group vibrations present in the 1200 cm(-1) region. TEP displays two prominent peaks at 1268 cm(-1) and 1036 cm(-1) corresponding to P=O and (P)-O-C vibrations, respectively. A droplet of TEP solution in cyclohexane was deposited on gold and CARC substrates and after solvent evaporation PM-IRRAS spectra were collected in the 1200 cm(-1) region. The integrated peak area of the PO and (P)OC vibrations was used to construct calibration curves and to determine the experimental limit of detection (LoD). In the case of gold as the substrate the estimated LoD of ~0.48 μg and 1.23 μg was obtained for the P=O and (P)-O-C vibrations, respectively. In the case of CARC, a LoD of 24 μg was determined. These detection limits are at least 3 orders of magnitude lower than the typical lethal dose of G and V-series nerve agents, demonstrating potential of PM-IRRAS for non-contact detection of these CWAs. PMID:22769035

  4. Being an "Agent Provocateur": Utilising Online Spaces for Teacher Professional Development in Virtual Simulation Games

    ERIC Educational Resources Information Center

    deNoyelles, Aimee; Raider-Roth, Miriam

    2016-01-01

    This article details the results of an action research study which investigated how teachers used online learning community spaces to develop and support their teaching and learning of the Jewish Court of All Time (JCAT), a web-mediated, character-playing, simulation game that engages participants with social, historical and cultural curricula.…

  5. Optical detection of chemical warfare agents and toxic industrial chemicals: Simulation

    NASA Astrophysics Data System (ADS)

    Webber, Michael E.; Pushkarsky, Michael; Patel, C. Kumar N.

    2005-06-01

    We present an analysis of optical techniques for the detection of chemical warfare agents and toxic industrial chemicals in real-world conditions. We analyze the problem of detecting a target species in the presence of a multitude of interferences that are often stochastic and we provide a broadly applicable technique for evaluating the sensitivity, probability of false positives (PFP), and probability of false negatives (PFN) for a sensor through the illustrative example of a laser photoacoustic spectrometer (L-PAS). This methodology includes (1) a model of real-world air composition, (2) an analytical model of an actual field-deployed L-PAS, (3) stochasticity in instrument response and air composition, (4) repeated detection calculations to obtain statistics and receiver operating characteristic curves, and (5) analyzing these statistics to determine the sensor's sensitivity, PFP, and PFN. This methodology was used to analyze variations in sensor design and ambient conditions, and can be utilized as a framework for comparing different sensors.

  6. Monte Carlo simulations of dose enhancement around gold nanoparticles used as X-ray imaging contrast agents and radiosensitizers

    NASA Astrophysics Data System (ADS)

    Li, W. B.; Müllner, M.; Greiter, M. B.; Bissardon, C.; Xie, W. Z.; Schlatll, H.; Oeh, U.; Li, J. L.; Hoeschen, C.

    2014-03-01

    Gold nanoparticles (GNPs) were demonstrated as X-ray imaging contrast agents and radiosensitizers in mice. However, the translational medical applications of GNPs in to the clinical practice need further detailed information on the biological effects related to the enhanced doses in malignant and healthy cells. The idea of improving radiotherapy with high atomic number materials, especially gold foils, was initiated in our research unit in the 1980s. Recently, experimental and theoretical efforts were made to investigate the potential improvement of imaging and radiotherapy with GNPs. Initially, the present work attempts to validate the dose enhancement effects of GNPs to cancer cells; secondly, it intends to examine the possible side effects on healthy cells when using GNPs as X-ray contrast agent. In this study, three Monte Carlo simulation programs, namely PENELOPE-2011, GEANT4 and EGSnrc were used to simulate the local energy deposition and the resulting dose enhancement of GNPs. Diameters of the GNPs were assumed to be 2 nm, 15 nm, 50 nm, 100 nm and 200 nm. The X-ray energy spectra for irradiation were 60 kVp, 80 kVp, 100 kVp, 150 kVp with a filtering of 2.7 mm Al for projectional radiography, and 8 mm Al for 100 kVp and 150 kVp for computed tomography. Additional peak energy of 200 kVp was simulated for radiotherapy purpose. The information of energy deposition and dose enhancement can help understanding the physical processes of medical imaging and the implication of nanoparticles in radiotherapy.

  7. Final report for the endowment of simulator agents with human-like episodic memory LDRD.

    SciTech Connect

    Speed, Ann Elizabeth; Lippitt, Carl Edward; Thomas, Edward Victor; Xavier, Patrick Gordon; Forsythe, Christi A.; Schaller, Mark J.; Schoenwald, David Alan

    2003-12-01

    This report documents work undertaken to endow the cognitive framework currently under development at Sandia National Laboratories with a human-like memory for specific life episodes. Capabilities have been demonstrated within the context of three separate problem areas. The first year of the project developed a capability whereby simulated robots were able to utilize a record of shared experience to perform surveillance of a building to detect a source of smoke. The second year focused on simulations of social interactions providing a queriable record of interactions such that a time series of events could be constructed and reconstructed. The third year addressed tools to promote desktop productivity, creating a capability to query episodic logs in real time allowing the model of a user to build on itself based on observations of the user's behavior.

  8. β-Glucan as an encapsulating agent: Effect on probiotic survival in simulated gastrointestinal tract.

    PubMed

    Shah, Asima; Gani, Adil; Ahmad, Mudasir; Ashwar, Bilal Ahmad; Masoodi, F A

    2016-01-01

    Three strains of probiotics Lactobacillus casei, Lactobacillus brevis, and Lactobacillus plantarum were encapsulated in β-glucan matrix using emulsion technique. Further the encapsulated cells were studied for their tolerance in simulated gastrointestinal conditions and its storage stability. The average encapsulation efficiency of β-glucan-probiotic beads was found to be 74.01%. The surface morphology of β-glucan containing bacteria was studied using SEM. The noteworthy absorptions in the FT-IR spectra between 1300-900 cm(-1) and 2918-2925 cm(-1) corresponds to the presence of bacteria into the glucan matrix. Also, the thermal stability of β-glucan was evaluated using Differential Scanning Calorimeter. The efficiency of β-glucan in protecting the surviability of probiotic cells under simulated gastrointestinal conditions was studied. Results revealed significant (p<0.05) improvement to tolerance when the encapsulated cells were subjected to stresses like low pH, heat treatment, simulated intestinal conditions and storage. PMID:26562556

  9. Agent-Based Simulations of Malaria Transmissions with Applications to a Study Site in Thailand

    NASA Technical Reports Server (NTRS)

    Kiang, Richard K.; Adimi, Farida; Zollner, Gabriela E.; Coleman, Russell E.

    2006-01-01

    The dynamics of malaria transmission are driven by environmental, biotic and socioeconomic factors. Because of the geographic dependency of these factors and the complex interactions among them, it is difficult to generalize the key factors that perpetuate or intensify malaria transmission. Methods: Discrete event simulations were used for modeling the detailed interactions among the vector life cycle, sporogonic cycle and human infection cycle, under the explicit influences of selected extrinsic and intrinsic factors. Meteorological and environmental parameters may be derived from satellite data. The output of the model includes the individual infection status and the quantities normally observed in field studies, such as mosquito biting rates, sporozoite infection rates, gametocyte prevalence and incidence. Results were compared with mosquito vector and human malaria data acquired over 4.5 years (June 1999 - January 2004) in Kong Mong Tha, a remote village in Kanchanaburi Province, western Thailand. Results: Three years of transmissions of vivax and falciparum malaria were simulated for a hypothetical hamlet with approximately 1/7 of the study site population. The model generated results for a number of scenarios, including applications of larvicide and insecticide, asymptomatic cases receiving or not receiving treatment, blocking malaria transmission in mosquito vectors, and increasing the density of farm (host) animals in the hamlet. Transmission characteristics and trends in the simulated results are comparable to actual data collected at the study site.

  10. First-principles molecular dynamics simulations of condensed-phase V-type nerve agent reaction pathways and energy barriers.

    PubMed

    Gee, Richard H; Kuo, I-Feng W; Chinn, Sarah C; Raber, Ellen

    2012-03-14

    Computational studies of condensed-phase chemical reactions are challenging in part because of complexities in understanding the effects of the solvent environment on the reacting chemical species. Such studies are further complicated due to the demanding computational resources required to implement high-level ab initio quantum chemical methods when considering the solvent explicitly. Here, we use first-principles molecular dynamics simulations to examine condensed-phase decontamination reactions of V-type nerve agents in an explicit aqueous solvent. Our results include a detailed study of hydrolysis, base-hydrolysis, and nucleophilic oxidation of both VX and R-VX, as well as their protonated counterparts (i.e., VXH(+) and R-VXH(+)). The decontamination mechanisms and chemical reaction energy barriers, as determined from our simulations, are found to be in good agreement with experiment. The results demonstrate the applicability of using such simulations to assist in understanding new decontamination technologies or other applications that require computational screening of condensed-phase chemical reaction mechanisms. PMID:22298156

  11. Measurements of Raman scattering in the middle ultraviolet band from persistent chemical warfare agents

    NASA Astrophysics Data System (ADS)

    Kullander, Fredrik; Landström, Lars; Lundén, Hampus; Mohammed, Abdesalam; Olofsson, Göran; Wästerby, Pär.

    2014-05-01

    The very low Raman scattering cross section and the fluorescence background limit the measuring range of Raman based instruments operating in the visible or infrared band. We are exploring if laser excitation in the middle ultraviolet (UV) band between 200 and 300 nm is useful and advantageous for detection of persistent chemical warfare agents (CWA) on various kinds of surfaces. The UV Raman scattering from tabun, mustard gas, VX and relevant simulants in the form of liquid surface contaminations has been measured using a laboratory experimental setup with a short standoff distance around 1 meter. Droplets having a volume of 1 μl were irradiated with a tunable pulsed laser swept within the middle UV band. A general trend is that the signal strength moves through an optimum when the laser excitation wavelength is swept between 240 and 300 nm. The signal from tabun reaches a maximum around 265 nm, the signal from mustard gas around 275 nm. The Raman signal from VX is comparably weak. Raman imaging by the use of a narrow bandpass UV filter is also demonstrated.

  12. Metal-ion catalyzed oxidation of a G-agent simulant by oxone. Final report Oct 89-Dec 90

    SciTech Connect

    Leslie, D.R.; Ward, J.R.

    1992-07-01

    By means of the ability of oxone to oxidize sulphur, oxone has been shown to be a rapid decontaminant for mustard or VX. G-agents, such as sarin or soman, are difficult to oxidize, and all means to decontaminate sarin or soman are based on hydrolysis. To see if oxone might have utility as a general decontaminant, experiments were run to see if the ability of oxone to destroy organophosphorus esters could be enhanced with transition-metal catalysts. Hydrolysis of the G-agent simulant diisopropyl methylphosphonate (DIMP) was promoted in oxone solution by the presence of such low valent metal ions as cobalt (II), chromium (III), or manganese (II). The reaction is initiated by radical formation from decomposition of HO-SO3. Radical chains may be terminated by dimerization of S04-, other reactions forming 02, or by reduction of the radical to S04= by low valent metal ion. The radical can also reduce the oxidized metal ion back to the original low valent state, thereby providing a path for turnover of the metal ion. The relatively slow rate and the potential for contaminants in field application that could react with the SO4- radicals make it unlikely that metal ion catalysis of oxone decomposition will prove to be a useful decontaminant. Decontamination, NMR, Chemical agents, Metal-ion catalysis, Chromium (III), DIMP, Oxone, Kinetics. This paper describes the effect of a crystal field, according to site symmetry, upon the magnetic quantum-level structure of an atomic ion, as expressed in electric dipole transitions (a corresponding treatment for magnetic dipole transitions, in the original German, is not included). Crystal field Magnetic quantum numbers Atomic ion.

  13. Transport behavior of surrogate biological warfare agents in a simulated landfill: effect of leachate recirculation and water infiltration.

    PubMed

    Saikaly, Pascal E; Hicks, Kristin; Barlaz, Morton A; de Los Reyes, Francis L

    2010-11-15

    An understanding of the transport behavior of biological warfare (BW) agents in landfills is required to evaluate the suitability of landfills for the disposal of building decontamination residue (BDR) following a bioterrorist attack on a building. Surrogate BW agents, Bacillus atrophaeus spores and Serratia marcescens, were spiked into simulated landfill reactors that were filled with synthetic building debris (SBD) and operated for 4 months with leachate recirculation or water infiltration. Quantitative polymerase chain reaction (Q-PCR) was used to monitor surrogate transport. In the leachate recirculation reactors, <10% of spiked surrogates were eluted in leachate over 4 months. In contrast, 45% and 31% of spiked S. marcescens and B. atrophaeus spores were eluted in leachate in the water infiltration reactors. At the termination of the experiment, the number of retained cells and spores in SBD was measured over the depth of the reactor. Less than 3% of the total spiked S. marcescens cells and no B. atrophaeus spores were detected in SBD. These results suggest that significant fractions of the spiked surrogates were strongly attached to SBD. PMID:20973546

  14. Interaction of collagen with chlorosulphonated paraffin tanning agents: Fourier transform infrared spectroscopic analysis and molecular dynamics simulations.

    PubMed

    Monti, Susanna; Bramanti, Emilia; Della Porta, Valentina; Onor, Massimo; D'Ulivo, Alessandro; Barone, Vincenzo

    2013-09-21

    The binding of chlorosulphonated paraffins to collagen triple helices is studied by means of classical molecular dynamics simulations and experimental spectroscopic techniques in order to disclose the principal characteristics of their interaction during the leather fattening process. Indeed, collagen is the main target to develop new leather modifying agents with specific characteristics, and an accurate design of the collagen binders, supported by predictive computational strategies, could be a successful tool to obtain new effective eco-compatible compounds able to impart to the leather the required functionalities and distinctive mechanical properties. Possible effects caused by the tanning agents on the collagen matrix have been identified from both experimental and theoretical points of view. Computational data in agreement with experiment have revealed that chlorosulphonated paraffins can interact favorably with the collagen residues having amine groups in their side chains (Arg, Lys, Asn and Gln) and reduce the tendency of the solvated collagen matrix to swell. However, the interference of chlorosulphonated paraffins with the unfolding process, which is operated mainly by the action of water, can be due both to covalent cross-linking of the collagen chains and intermolecular hydrogen bonding interactions involving also the hydroxyl groups of Hyp, Ser and Thr residues. PMID:23904010

  15. Biochemical characterization and molecular dynamic simulation of β-sitosterol as a tubulin-binding anticancer agent.

    PubMed

    Mahaddalkar, Tejashree; Suri, Charu; Naik, Pradeep Kumar; Lopus, Manu

    2015-08-01

    Βeta-sitosterol (β-SITO), a phytosterol present in pomegranate, peanut, corn oil, almond, and avocado, has been recognized to offer health benefits and potential clinical uses. β-SITO is orally bioavailable and, as a constituent of edible natural products, is considered to have no undesired side effects. It has also been considered as a potent anticancer agent. However, the molecular mechanism of action of β-SITO as a tubulin-binding anticancer agent and its binding site on tubulin are poorly understood. Using a combination of biochemical analyses and molecular dynamic simulation, we investigated the molecular details of the binding interactions of β-SITO with tubulin. A polymer mass assay comparing the effects of β-SITO and of taxol and vinblastine on tubulin assembly showed that this phytosterol stabilized microtubule assembly in a manner similar to taxol. An 8-anilino-1-naphthalenesulfonic acid assay confirmed the direct interaction of β-SITO with tubulin. Although β-SITO did not show direct binding to the colchicine site on tubulin, it stabilized the colchicine binding. Interestingly, no sulfhydryl groups of tubulin were involved in the binding interaction of β-SITO with tubulin. Based on the results from the biochemical assays, we computationally modeled the binding of β-SITO with tubulin. Using molecular docking followed by molecular dynamic simulations, we found that β-SITO binds tubulin at a novel site (which we call the 'SITO site') adjacent to the colchicine and noscapine sites. Our data suggest that β-SITO is a potent anticancer compound that interferes with microtubule assembly dynamics by binding to a novel site on tubulin. PMID:25912799

  16. Biophotonic ring resonator for ultrasensitive detection of DMMP as a simulant for organophosphorus agents.

    PubMed

    Bonnot, Karine; Cuesta-Soto, Francisco; Rodrigo, Manuel; Varriale, Antonio; Sanchez, Nuria; D'Auria, Sabato; Spitzer, Denis; Lopez-Royo, Francisco

    2014-05-20

    Combining photonic integrated circuits with a biologically based sensing approach has the ability to provide a new generation of portable and low-cost sensor devices with a high specificity and sensitivity for a number of applications in environmental monitoring, defense, and homeland security. We report herein on the specific biosensing under continuous air flow of DMMP, which is commonly used as a simulant and a precursor for the synthesis of Sarin. The proposed technology is based on the selective recognition of the targeted DMMP molecule by specifically modified proteins immobilized on photonic structures. The response of the biophotonic structures shows a high stability and accuracy over 3 months, allowing for the detection in diluted air of DMMP at concentration as low as 35 μg/m(3) (6.8 ppb) in less than 15 min. The performance of the developed technology satisfies most current homeland and military security requirements. PMID:24766275

  17. Concepts and theoretical specifications of a Coastal Vulnerability Dynamic Simulator (COVUDS): A multi-agent system for simulating coastal vulnerability towards management of coastal ecosystem services

    NASA Astrophysics Data System (ADS)

    Orencio, P. M.; Endo, A.; Taniguchi, M.

    2014-12-01

    Disaster-causing natural hazards such as floods, erosions, earthquakes or slope failures were particularly observed to be concentrated in certain geographical regions. In the Asia-pacific region, coastal ecosystems were suffering because of perennial threats driven by chronic fluctuations in climate variability (e.g., typhoons, ENSO), or by dynamically occurring events (e.g., earthquakes, tsunamis). Among the many people that were found prone to such a risky condition were the ones inhabiting near the coastal areas. Characteristically, aside from being located at the forefront of these events, the coastal communities have impacted the resource by the kind of behavioral patterns they exhibited, such as overdependence and overexploitation to achieve their wellbeing. In this paper, we introduce the development of an approach to an assessment of the coupled human- environment using a multi- agent simulation (MAS) model known as Coastal Vulnerability Dynamic Simulator (COVUDS). The COVUDS comprised a human- environmental platform consisting multi- agents with corresponding spatial- based dynamic and static variables. These variables were used to present multiple hypothetical future situations that contribute to the purpose of supporting a more rational management of the coastal ecosystem and their environmental equities. Initially, we present the theoretical and conceptual components that would lead to the development of the COVUDS. These consisted of the human population engaged in behavioral patterns affecting the conditions of coastal ecosystem services; the system of the biophysical environment and changes in patches brought by global environment and local behavioral variations; the policy factors that were important for choosing area- specific interventions; and the decision- making mechanism that integrates the first three components. To guide a future scenario-based application that will be undertaken in a coastal area in the Philippines, the components of the

  18. Rapid response behavior, at room temperature, of a nanofiber-structured TiO2 sensor to selected simulant chemical-warfare agents.

    PubMed

    Ma, Xingfa; Zhu, Tao; Xu, Huizhong; Li, Guang; Zheng, Junbao; Liu, Aiyun; Zhang, Jianqin; Du, Huatai

    2008-02-01

    A chemical prototype sensor was constructed based on nanofiber-structured TiO2 and highly sensitive quartz resonators. The gas-sensing behavior of this new sensor to selected simulant warfare agents was investigated at room temperature. Results showed rapid response and good reversibility of this sensor when used with high-purity nitrogen. This provides a simple approach to preparation of materials needed as chemical sensors for selected organic volatiles or warfare agents. PMID:18094961

  19. Detection of aqueous phase chemical warfare agent degradation products by negative mode ion mobility time-of-flight mass spectrometry [IM(tof)MS].

    PubMed

    Steiner, Wes E; Harden, Charles S; Hong, Feng; Klopsch, Steve J; Hill, Herbert H; McHugh, Vincent M

    2006-02-01

    The use of negative ion monitoring mode with an atmospheric pressure ion mobility orthogonal reflector time-of-flight mass spectrometer [IM(tof)MS] to detect chemical warfare agent (CWA) degradation products from aqueous phase samples has been determined. Aqueous phase sampling used a traditional electrospray ionization (ESI) source for sample introduction and ionization. Certified reference materials (CRM) of CWA degradation products for the detection of Schedule 1, 2, or 3 toxic chemicals or their precursors as defined by the chemical warfare convention (CWC) treaty verification were used in this study. A mixture of six G-series nerve related CWA degradation products (EMPA, IMPA, EHEP, IHEP, CHMPA, and PMPA) and their related collision induced dissociation (CID) fragment ions (MPA and EPA) were found in each case to be clearly resolved and detected using the IM(tof)MS instrument in negative ion monitoring mode. Corresponding ions, masses, drift times, K(o) values, and signal intensities for each of the CWA degradation products are reported. PMID:16413205

  20. Superfund TIO videos. Set A. Regulatory overview - CERCLA's relationship to other programs: RCRA, Title III, UST, CWA, SDWA. Part 1. Audio-Visual

    SciTech Connect

    Not Available

    1990-01-01

    The videotape is divided into five sections. Section 1 provides definitions and historical information on both the Resource Conservation and Recovery Act (RCRA) and the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). The four types of RCRA regulatory programs - Subtitles C, D, I, and J - are described. Treatment, storage, and disposal (TSD) and recycling facilities are also discussed. Section 2 discusses the history behind the Emergency Planning and Community Right-to-Know Act (Title III). The four major provisions of Title III, which are emergency planning, emergency release notification, community right-to-know reporting, and the toxic chemical release inventory are covered. Section 3 outlines the UST program covering notification, record keeping, and the UST Trust Fund. Section 4 outlines the six major provisions of the Clean Water Act (CWA): water quality, pretreatment, prevention of oil and hazardous substance discharges, responses to oil and hazardous substance discharges, discharges of hazardous substances into the ocean, and dredge and fill. Section 5 explains the purpose, regulations, and standards of the Safe Drinking Water Act (SDWA). Specific issues such as underground injection, sole source aquifers, and lead contamination are discussed.

  1. Acute environmental toxicity and persistence of DEM, a chemical agent simulant: Diethyl malonate. [Diethyl malonate

    SciTech Connect

    Cataldo, D.A.; Ligotke, M.W.; Harvey, S.D.; Fellows, R.J.; Li, Shu-mei W.; Van Voris, P.; Wentsel, R.S.

    1990-05-01

    The purpose of the following chemical simulant studies is to assess the potential acute environmental effects and persistence of diethyl malonate (DEM). Deposition velocities for DEM to soil surfaces ranged from 0.04 to 0.2 cm/sec. For foliar surfaces, deposition velocities ranged from 0.0002 cm/sec at low air concentrations to 0.05 cm/sec for high dose levels. The residence times or half-lives of DEM deposited to soils was 2 h for the fast component and 5 to 16 h for the residual material. DEM deposited to foliar surfaces also exhibited biphasic depuration. The half-life of the short residence time component ranged from 1 to 3 h, while the longer time component had half-times of 16 to 242 h. Volatilization and other depuration mechanisms reduce surface contaminant levels in both soils and foliage to less than 1% of initial dose within 96 h. DEM is not phytotoxic at foliar mass loading levels of less than 10 {mu}m/cm{sup 2}. However, severe damage is evident at mass loading levels in excess of 17 {mu}g/cm{sup 2}. Tall fescue and sagebrush were more affected than was short-needle pine, however, mass loading levels were markedly different. Regrowth of tall fescue indicated that the effects of DEM are residual, and growth rates are affected only at higher mass loadings through the second harvest. Results from in vitro testing of DEM indicated concentrations below 500 {mu}g/g dry soil generally did not negatively impact soil microbial activity. Short-term effects of DEM were more profound on soil dehydrogenase activity than on soil phosphatase activity. No enzyme inhibition or enhancement was observed after 28 days in incubation. Results of the earthworm bioassay indicate survival to be 86 and 66% at soil doses of 107 and 204 {mu}g DEM/cm{sup 2}, respectively. At higher dose level, activity or mobility was judged to be affected in over 50% of the individuals. 21 refs., 10 figs., 15 tabs.

  2. Laboratory conditions and safety in a chemical warfare agent analysis and research laboratory.

    PubMed

    Kenar, Levent; Karayilanoğlu, Turan; Kose, Songul

    2002-08-01

    Toxic chemicals have been used as weapons of war and also as means of terrorist attacks on civilian populations. Research focusing on chemical warfare agents (CWAs) may be associated with an increased risk of exposure to and contamination by these agents. This article summarizes some of the regulations concerning designation and safety in a CWA analysis and research laboratory and medical countermeasures in case of an accidental exposure. The design of such a laboratory, coupled with a set of safety guidelines, provides for the safe conduct of research and studies involving CWAs. Thus, a discussion of decontamination and protection means against CWAs is also presented. PMID:12188231

  3. Binding of chemical warfare agent simulants as guests in a coordination cage: contributions to binding and a fluorescence-based response.

    PubMed

    Taylor, Christopher G P; Piper, Jerico R; Ward, Michael D

    2016-05-01

    Cubic coordination cages act as competent hosts for several alkyl phosphonates used as chemical warfare agent simulants; a range of cage/guest structures have been determined, contributions to guest binding analysed, and a fluorescent response to guest binding demonstrated. PMID:27020844

  4. In situ infrared aerosol spectroscopy for a variety of nerve agent simulants using flow-through photoacoustics.

    PubMed

    Gurton, Kristan P; Felton, Melvin; Dahmani, Rachid; Ligon, David

    2007-09-01

    We present newly measured results of an ongoing experimental program established to measure optical cross sections in the mid- and long-wave infrared for a variety of chemically and biologically based aerosols. For this study we consider only chemically derived aerosols, and in particular, a group of chemical compounds often used as simulants for the detection of extremely toxic organophosphorus nerve agents. These materials include: diethyl methylphosphonate (DEMP), dimethyl methylphosphonate (DMMP), diisopropyl methylphosphonate (DIMP), and diethyl phthalate (DEP). As reported in a prior study [Appl. Opt. 44, 4001 (2005)], we combine two optical techniques well suited for aerosol spectroscopy [i.e., flow-through photoacoustics and Fourier transform infrared (FTIR) emission spectroscopy], to measure in situ the absolute extinction and absorption cross sections over a variety of wavelengths spanning the IR spectral region from 3 to 13 mum. Aerosol size distribution(s), particle number density, and dosimetric measurements are recorded simultaneously in order to present optical cross sections that are aerosol mass normalized, i.e., m(2)/gram. Photoacoustic results, conducted at a series of CO(2) laser lines, compare well with measured broadband FTIR spectral extinction. Both FTIR and photoacoustic data also compare well with Mie theory calculations based on measured size distributions and previously published complex indices of refraction. PMID:17805369

  5. Multiobjective Decision Making Policies and Coordination Mechanisms in Hierarchical Organizations: Results of an Agent-Based Simulation

    PubMed Central

    2014-01-01

    This paper analyses how different coordination modes and different multiobjective decision making approaches interfere with each other in hierarchical organizations. The investigation is based on an agent-based simulation. We apply a modified NK-model in which we map multiobjective decision making as adaptive walk on multiple performance landscapes, whereby each landscape represents one objective. We find that the impact of the coordination mode on the performance and the speed of performance improvement is critically affected by the selected multiobjective decision making approach. In certain setups, the performances achieved with the more complex multiobjective decision making approaches turn out to be less sensitive to the coordination mode than the performances achieved with the less complex multiobjective decision making approaches. Furthermore, we present results on the impact of the nature of interactions among decisions on the achieved performance in multiobjective setups. Our results give guidance on how to control the performance contribution of objectives to overall performance and answer the question how effective certain multiobjective decision making approaches perform under certain circumstances (coordination mode and interdependencies among decisions). PMID:25152926

  6. Structural elucidation of direct analysis in real time ionized nerve agent simulants with infrared multiple photon dissociation spectroscopy.

    PubMed

    Rummel, Julia L; Steill, Jeffrey D; Oomens, Jos; Contreras, Cesar S; Pearson, Wright L; Szczepanski, Jan; Powell, David H; Eyler, John R

    2011-06-01

    Infrared multiple photon dissociation (IRMPD) was used to generate vibrational spectra of ions produced with a direct analysis in real time (DART) ionization source coupled to a 4.7 T Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer. The location of protonation on the nerve agent simulants diisopropyl methylphosphonate (DIMP) and dimethyl methylphosphonate (DMMP) was studied while solutions of the compounds were introduced for extended periods of time with a syringe pump. Theoretical vibrational spectra were generated with density functional theory calculations. Visual comparison of experimental mid-IR IRMPD spectra and theoretical spectra could not establish definitively if a single structure or a mixture of conformations was present for the protonated parent of each compound. However, theoretical calculations, near-ir IRMPD spectra, and frequency-to-frequency and statistical comparisons indicated that the protonation site for both DIMP and DMMP was predominantly, if not exclusively, the phosphonyl oxygen instead of one of the oxygen atoms with only single bonds. PMID:21491962

  7. In situ infrared aerosol spectroscopy for a variety of nerve agent simulants using flow-through photoacoustics

    NASA Astrophysics Data System (ADS)

    Gurton, Kristan P.; Felton, Melvin; Dahmani, Rachid; Ligon, David

    2007-09-01

    We present newly measured results of an ongoing experimental program established to measure optical cross sections in the mid- and long-wave infrared for a variety of chemically and biologically based aerosols. For this study we consider only chemically derived aerosols, and in particular, a group of chemical compounds often used as simulants for the detection of extremely toxic organophosphorus nerve agents. These materials include: diethyl methylphosphonate (DEMP), dimethyl methylphosphonate (DMMP), diisopropyl methylphosphonate (DIMP), and diethyl phthalate (DEP). As reported in a prior study [Appl. Opt. 44, 4001 (2005)], we combine two optical techniques well suited for aerosol spectroscopy [i.e., flow-through photoacoustics and Fourier transform infrared (FTIR) emission spectroscopy], to measure in situ the absolute extinction and absorption cross sections over a variety of wavelengths spanning the IR spectral region from 3 to 13 μm. Aerosol size distribution(s), particle number density, and dosimetric measurements are recorded simultaneously in order to present optical cross sections that are aerosol mass normalized, i.e., m2/gram. Photoacoustic results, conducted at a series of CO2 laser lines, compare well with measured broadband FTIR spectral extinction. Both FTIR and photoacoustic data also compare well with Mie theory calculations based on measured size distributions and previously published complex indices of refraction.

  8. Multiobjective decision making policies and coordination mechanisms in hierarchical organizations: results of an agent-based simulation.

    PubMed

    Leitner, Stephan; Wall, Friederike

    2014-01-01

    This paper analyses how different coordination modes and different multiobjective decision making approaches interfere with each other in hierarchical organizations. The investigation is based on an agent-based simulation. We apply a modified NK-model in which we map multiobjective decision making as adaptive walk on multiple performance landscapes, whereby each landscape represents one objective. We find that the impact of the coordination mode on the performance and the speed of performance improvement is critically affected by the selected multiobjective decision making approach. In certain setups, the performances achieved with the more complex multiobjective decision making approaches turn out to be less sensitive to the coordination mode than the performances achieved with the less complex multiobjective decision making approaches. Furthermore, we present results on the impact of the nature of interactions among decisions on the achieved performance in multiobjective setups. Our results give guidance on how to control the performance contribution of objectives to overall performance and answer the question how effective certain multiobjective decision making approaches perform under certain circumstances (coordination mode and interdependencies among decisions). PMID:25152926

  9. Liquid-liquid-solid microextraction and detection of nerve agent simulants by on-membrane Fourier transform infrared spectroscopy.

    PubMed

    Garg, Prabhat; Purohit, Ajay; Tak, Vijay K; Kumar, Ajeet; Dubey, D K

    2012-11-01

    A coupling of novel liquid-liquid-solid microextraction (LLSME) technique based on porous hydrophobic membrane and Fourier-transform infrared spectroscopy has been presented for the detection, identification and quantification of markers and simulants of nerve agents. Two isomers O,O'-dihexyl methylphosphonate (DHMP) and O,O'-dipentyl isopropylphosphonate (DPIPP) were chosen as model analytes for the study. In the present technique, organic phase was immobilised within the pores of membrane after fixing it in an assembly, which was then immersed into aqueous sample of target analytes for extraction. The analytes were directly determined on the surface of membrane by FTIR spectroscopy without elution. On comparison with solid phase microextraction (SPME), LLSME was found to be much more efficient. The method was optimised and quantitative analyses were performed using calibration curves obtained via Beer's law and employing processing of spectra obtained, via a multivariate calibration technique partial least square (PLS). Relative standard deviations (RSDs) for intraday repeatability and interday reproducibility were found to be in the range of 0.20-0.50% and 0.20-0.60%, respectively. Limit of detection (LOD) was achieved up to 15 ng mL(-1). Applicability of the method was tested with an unknown real sample obtained in an international official proficiency test (OPT). PMID:23084054

  10. Modeling the 2014 Ebola Virus Epidemic - Agent-Based Simulations, Temporal Analysis and Future Predictions for Liberia and Sierra Leone.

    PubMed

    Siettos, Constantinos; Anastassopoulou, Cleo; Russo, Lucia; Grigoras, Christos; Mylonakis, Eleftherios

    2015-01-01

    We developed an agent-based model to investigate the epidemic dynamics of Ebola virus disease (EVD) in Liberia and Sierra Leone from May 27 to December 21, 2014. The dynamics of the agent-based simulator evolve on small-world transmission networks of sizes equal to the population of each country, with adjustable densities to account for the effects of public health intervention policies and individual behavioral responses to the evolving epidemic. Based on time series of the official case counts from the World Health Organization (WHO), we provide estimates for key epidemiological variables by employing the so-called Equation-Free approach. The underlying transmission networks were characterized by rather random structures in the two countries with densities decreasing by ~19% from the early (May 27-early August) to the last period (mid October-December 21). Our estimates for the values of key epidemiological variables, such as the mean time to death, recovery and the case fatality rate, are very close to the ones reported by the WHO Ebola response team during the early period of the epidemic (until September 14) that were calculated based on clinical data. Specifically, regarding the effective reproductive number Re, our analysis suggests that until mid October, Re was above 2.3 in both countries; from mid October to December 21, Re dropped well below unity in Liberia, indicating a saturation of the epidemic, while in Sierra Leone it was around 1.9, indicating an ongoing epidemic. Accordingly, a ten-week projection from December 21 estimated that the epidemic will fade out in Liberia in early March; in contrast, our results flashed a note of caution for Sierra Leone since the cumulative number of cases could reach as high as 18,000, and the number of deaths might exceed 5,000, by early March 2015. However, by processing the reported data of the very last period (December 21, 2014-January 18, 2015), we obtained more optimistic estimates indicative of a remission of

  11. [Susceptibility of clinically-isolated bacteria strains to respiratory quinolones and evaluation of antimicrobial agent efficacy by Monte Carlo simulation].

    PubMed

    Kosaka, Tadashi; Yamada, Yukiji; Kimura, Takeshi; Kodama, Mai; Fujitomo, Yumiko; Masaki, Nakanishi; Toshiaki, Komori; Keisuke, Shikata; Fujita, Naohisa

    2016-02-01

    Respiratory quinolones (RQs) are broad-spectrum antimicrobial agents used for the treatment of a wide variety of community-acquired and nosocomial infections. However, bacterial resistance to quinolones has been on the increase. In this study, we investigated the predicted efficacy of RQs for various strains of 9 bacterial species clinically isolated at our university hospital using the Monte Carlo simulation (MCS) method based on pharmacokinetics/pharmacodynamics modeling. In addition, the influence of the patients' renal function on the efficacy of RQs was evaluated. We surveyed antimicrobial susceptibility testing of 9 bacterial species (n = number of strains) [Streptococcus pneumoniae (n = 15), Streptococcus pyogenes (n = 14), Streptococcus agalactiae (n = 19), methicillin-susceptible Staphylococcus aureus (MSSA) (n = 24), Escherichia coli (n = 35), Haemophilus influenzae (n = 17), Klebsiella pneumoniae (n = 14), Pseudomonas aeruginosa (n = 31), and Moraxella catarrhalis (n = 11)] to 4 RQs [garenoxacin (GRNX), levofloxacin (LVFX), sitafloxacin (STFX), and moxifloxacin (MFLX)]. We found that compared with the other RQs, Gram-positive cocci was most resistant to LVFX, and that the minimum inhibitory concentration (MIC₉₀) values for S. pneumoniae, S. pyogenes, S. agalactiae, and MSSA were high (2, 16, > 16, and 8 µg/mL, respectively). In regard to Gram-negative rods, the susceptibility of E. coli to RQs was found to be decreased, with the MIC₉₀ values of GRNX, LVFX, STFX, and MFLX being > 16, 16, 1, and 16 µg/mL, respectively. MCS revealed that the target attainment rate of the area under the unbound concentration-time curve divided by the MIC₉₀ (ƒ · AUC/MIC ratio), against S. pneumoniae was 86.9-100%, but against E. coli was low (52.1-66.2%). The ƒ · AUC/MIC target attainment rate of LVFX against S. pneumoniae, S. pyogenes, and S. agalactiae tended to decrease due to increased creatinine clearance, and that of LVFX and STFX against MSSA also

  12. Design of a multi-agent hydroeconomic model to simulate a complex human-water system: Early insights from the Jordan Water Project

    NASA Astrophysics Data System (ADS)

    Yoon, J.; Klassert, C. J. A.; Lachaut, T.; Selby, P. D.; Knox, S.; Gorelick, S.; Rajsekhar, D.; Tilmant, A.; Avisse, N.; Harou, J. J.; Gawel, E.; Klauer, B.; Mustafa, D.; Talozi, S.; Sigel, K.

    2015-12-01

    Our work focuses on development of a multi-agent, hydroeconomic model for purposes of water policy evaluation in Jordan. The model adopts a modular approach, integrating biophysical modules that simulate natural and engineered phenomena with human modules that represent behavior at multiple levels of decision making. The hydrologic modules are developed using spatially-distributed groundwater and surface water models, which are translated into compact simulators for efficient integration into the multi-agent model. For the groundwater model, we adopt a response matrix method approach in which a 3-dimensional MODFLOW model of a complex regional groundwater system is converted into a linear simulator of groundwater response by pre-processing drawdown results from several hundred numerical simulation runs. Surface water models for each major surface water basin in the country are developed in SWAT and similarly translated into simple rainfall-runoff functions for integration with the multi-agent model. The approach balances physically-based, spatially-explicit representation of hydrologic systems with the efficiency required for integration into a complex multi-agent model that is computationally amenable to robust scenario analysis. For the multi-agent model, we explicitly represent human agency at multiple levels of decision making, with agents representing riparian, management, supplier, and water user groups. The agents' decision making models incorporate both rule-based heuristics as well as economic optimization. The model is programmed in Python using Pynsim, a generalizable, open-source object-oriented code framework for modeling network-based water resource systems. The Jordan model is one of the first applications of Pynsim to a real-world water management case study. Preliminary results from a tanker market scenario run through year 2050 are presented in which several salient features of the water system are investigated: competition between urban and

  13. Analysis of gaseous toxic industrial compounds and chemical warfare agent simulants by atmospheric pressure ionization mass spectrometry.

    PubMed

    Cotte-Rodríguez, Ismael; Justes, Dina R; Nanita, Sergio C; Noll, Robert J; Mulligan, Christopher C; Sanders, Nathaniel L; Cooks, R Graham

    2006-04-01

    The suitability of atmospheric pressure chemical ionization mass spectrometry as sensing instrumentation for the real-time monitoring of low levels of toxic compounds is assessed, especially with respect to public safety applications. Gaseous samples of nine toxic industrial compounds, NH3, H2S, Cl2, CS2, SO2, C2H4O, HBr, C6H6 and AsH3, and two chemical warfare agent simulants, dimethyl methylphosphonate (DMMP) and methyl salicylate (MeS), were studied. API-MS proves highly suited to this application, with speedy analysis times (<30 seconds), high sensitivity, high selectivity towards analytes, good precision, dynamic range and accuracy. Tandem MS methods were implemented in selected cases for improved selectivity, sensitivity, and limits of detection. Limits of detection in the parts-per-billion and parts-per-trillion range were achieved for this set of analytes. In all cases detection limits were well below the compounds' permissible exposure limits (PELs), even in the presence of added complex mixtures of alkanes. Linear responses, up to several orders of magnitude, were obtained over the concentration ranges studied (sub-ppb to ppm), with relative standard deviations less than 3%, regardless of the presence of alkane interferents. Receiver operating characteristic (ROC) curves are presented to show the performance trade-off between sensitivity, probability of correct detection, and false positive rate. A dynamic sample preparation system for the production of gas phase analyte concentrations ranging from 100 pptr to 100 ppm and capable of admixing gaseous matrix compounds and control of relative humidity and temperature is also described. PMID:16568176

  14. Modelling Temporal Schedule of Urban Trains Using Agent-Based Simulation and NSGA2-BASED Multiobjective Optimization Approaches

    NASA Astrophysics Data System (ADS)

    Sahelgozin, M.; Alimohammadi, A.

    2015-12-01

    Increasing distances between locations of residence and services leads to a large number of daily commutes in urban areas. Developing subway systems has been taken into consideration of transportation managers as a response to this huge amount of travel demands. In developments of subway infrastructures, representing a temporal schedule for trains is an important task; because an appropriately designed timetable decreases Total passenger travel times, Total Operation Costs and Energy Consumption of trains. Since these variables are not positively correlated, subway scheduling is considered as a multi-criteria optimization problem. Therefore, proposing a proper solution for subway scheduling has been always a controversial issue. On the other hand, research on a phenomenon requires a summarized representation of the real world that is known as Model. In this study, it is attempted to model temporal schedule of urban trains that can be applied in Multi-Criteria Subway Schedule Optimization (MCSSO) problems. At first, a conceptual framework is represented for MCSSO. Then, an agent-based simulation environment is implemented to perform Sensitivity Analysis (SA) that is used to extract the interrelations between the framework components. These interrelations is then taken into account in order to construct the proposed model. In order to evaluate performance of the model in MCSSO problems, Tehran subway line no. 1 is considered as the case study. Results of the study show that the model was able to generate an acceptable distribution of Pareto-optimal solutions which are applicable in the real situations while solving a MCSSO is the goal. Also, the accuracy of the model in representing the operation of subway systems was significant.

  15. Remote Continuous Wave and Pulsed Laser Raman Detection of Chemical Warfare Agents Simulants and Toxic Industrial Compounds

    NASA Astrophysics Data System (ADS)

    Ortiz-Rivera, William; Pacheco-Londoño, Leonardo C.; Hernández-Rivera, Samuel P.

    2010-09-01

    This study describes the design, assembly, testing and comparison of two Remote Raman Spectroscopy (RRS) systems intended for standoff detection of hazardous chemical liquids. Raman spectra of Chemical Warfare Agents Simulants (CWAS) and Toxic Industrial Compounds (TIC) were measured in the laboratory at a 6.6 m source-target distance using continuous wave (CW) laser detection. Standoff distances for pulsed measurements were 35 m for dimethyl methylphosphonate (DMMP) detection and 60, 90 and 140 m for cyclohexane detection. The prototype systems consisted of a Raman spectrometer equipped with a CCD detector (for CW measurements) and an I-CCD camera with time-gated electronics (for pulsed laser measurements), a reflecting telescope, a fiber optic assembly, a single-line CW laser source (514.5, 488.0, 351.1 and 363.8 nm) and a frequency-doubled single frequency Nd:YAG 532 nm laser (5 ns pulses at 10 Hz). The telescope was coupled to the spectrograph using an optical fiber, and filters were used to reject laser radiation and Rayleigh scattering. Two quartz convex lenses were used to collimate the light from the telescope from which the telescope-focusing eyepiece was removed, and direct it to the fiber optic assembly. To test the standoff sensing system, the Raman Telescope was used in the detection of liquid TIC: benzene, chlorobenzene, toluene, carbon tetrachloride, cyclohexane and carbon disulfide. Other compounds studied were CWAS: dimethylmethyl phosphonate, 2-chloroethyl ethyl sulfide and 2-(butylamino)-ethanethiol. Relative Raman scattering cross sections of liquid CWAS were measured using single-line sources at 532.0, 488.0, 363.8 and 351.1 nm. Samples were placed in glass and quartz vials at the standoff distances from the telescope for the Remote Raman measurements. The mass of DMMP present in water solutions was also quantified as part of the system performance tests.

  16. Analysis of CDC social control measures using an agent-based simulation of an influenza epidemic in a city

    PubMed Central

    2011-01-01

    Background The transmission of infectious disease amongst the human population is a complex process which requires advanced, often individual-based, models to capture the space-time details observed in reality. Methods An Individual Space-Time Activity-based Model (ISTAM) was applied to simulate the effectiveness of non-pharmaceutical control measures including: (1) refraining from social activities, (2) school closure and (3) household quarantine, for a hypothetical influenza outbreak in an urban area. Results Amongst the set of control measures tested, refraining from social activities with various compliance levels was relatively ineffective. Household quarantine was very effective, especially for the peak number of cases and total number of cases, with large differences between compliance levels. Household quarantine resulted in a decrease in the peak number of cases from more than 300 to around 158 for a 100% compliance level, a decrease of about 48.7%. The delay in the outbreak peak was about 3 to 17 days. The total number of cases decreased to a range of 3635-5403, that is, 63.7%-94.7% of the baseline value. When coupling control measures, household quarantine together with school closure was the most effective strategy. The resulting space-time distribution of infection in different classes of activity bundles (AB) suggests that the epidemic outbreak is strengthened amongst children and then spread to adults. By sensitivity analysis, this study demonstrated that earlier implementation of control measures leads to greater efficacy. Also, for infectious diseases with larger basic reproduction number, the effectiveness of non-pharmaceutical measures was shown to be limited. Conclusions Simulated results showed that household quarantine was the most effective control measure, while school closure and household quarantine implemented together achieved the greatest benefit. Agent-based models should be applied in the future to evaluate the efficacy of control

  17. The effect of nitrate, bicarbonate and natural organic matter on the degradation of sunscreen agent p-aminobenzoic acid by simulated solar irradiation.

    PubMed

    Mao, Liang; Meng, Cui; Zeng, Chao; Ji, Yuefei; Yang, Xi; Gao, Shixiang

    2011-11-15

    Our experiments revealed that a model sunscreen agent, p-aminobenzoic acid (PABA), can be effectively transformed through reactions that are mediated by simulated solar irradiation. We systematically explored the effects of nitrate ions, bicarbonate and different types of natural organic matter (NOM) on the degradation of PABA by simulated solar irradiation. Experimental data suggest that these components ubiquitous in nature water have different influence on the rates of the photoinduced removal of PABA. Products were extracted and analyzed using LC/MS and a total of four products probably resulting from OH and NO2 radicals attack were identified and the possible reaction pathways were proposed. The findings in this study provide useful information for understanding the environmental transformation of sunscreen agent in aquatic system. PMID:21975008

  18. On The Wealth Distribution Of A Simulated Kinetic Economy With An Arbitrary Fraction of Agents Networking Trading Opportunities

    NASA Astrophysics Data System (ADS)

    Khidzir, Sidiq Mohamad; Abdullah, Wan Ahmad Tajuddin Wan

    2008-05-01

    We study a trading model where agents trade money based on an arbitrary random fractions similar to works done by Chakraborti and Chatterjee, arXiv:0710.0917, but embed a networking capability to an arbitrary percentage of agents. We do this to see the effects on the power law in the wealth distribution. Our studies show that the percentage of networking affects the value of the Pareto Exponent.

  19. An Economic Analysis of Strategies to Control Clostridium Difficile Transmission and Infection Using an Agent-Based Simulation Model

    PubMed Central

    Nelson, Richard E.; Jones, Makoto; Leecaster, Molly; Samore, Matthew H.; Ray, William; Huttner, Angela; Huttner, Benedikt; Khader, Karim; Stevens, Vanessa W.; Gerding, Dale; Schweizer, Marin L.; Rubin, Michael A.

    2016-01-01

    Background A number of strategies exist to reduce Clostridium difficile (C. difficile) transmission. We conducted an economic evaluation of “bundling” these strategies together. Methods We constructed an agent-based computer simulation of nosocomial C. difficile transmission and infection in a hospital setting. This model included the following components: interactions between patients and health care workers; room contamination via C. difficile shedding; C. difficile hand carriage and removal via hand hygiene; patient acquisition of C. difficile via contact with contaminated rooms or health care workers; and patient antimicrobial use. Six interventions were introduced alone and "bundled" together: (a) aggressive C. difficile testing; (b) empiric isolation and treatment of symptomatic patients; (c) improved adherence to hand hygiene and (d) contact precautions; (e) improved use of soap and water for hand hygiene; and (f) improved environmental cleaning. Our analysis compared these interventions using values representing 3 different scenarios: (1) base-case (BASE) values that reflect typical hospital practice, (2) intervention (INT) values that represent implementation of hospital-wide efforts to reduce C. diff transmission, and (3) optimal (OPT) values representing the highest expected results from strong adherence to the interventions. Cost parameters for each intervention were obtained from published literature. We performed our analyses assuming low, normal, and high C. difficile importation prevalence and transmissibility of C. difficile. Results INT levels of the “bundled” intervention were cost-effective at a willingness-to-pay threshold of $100,000/quality-adjusted life-year in all importation prevalence and transmissibility scenarios. OPT levels of intervention were cost-effective for normal and high importation prevalence and transmissibility scenarios. When analyzed separately, hand hygiene compliance, environmental decontamination, and empiric

  20. Thread Group Multithreading: Accelerating the Computation of an Agent-Based Power System Modeling and Simulation Tool -- C GridLAB-D

    SciTech Connect

    Jin, Shuangshuang; Chassin, David P.

    2014-01-06

    GridLAB-DTM is an open source next generation agent-based smart-grid simulator that provides unprecedented capability to model the performance of smart grid technologies. Over the past few years, GridLAB-D has been used to conduct important analyses of smart grid concepts, but it is still quite limited by its computational performance. In order to break through the performance bottleneck to meet the need for large scale power grid simulations, we develop a thread group mechanism to implement highly granular multithreaded computation in GridLAB-D. We achieve close to linear speedups on multithreading version compared against the single-thread version of the same code running on general purpose multi-core commodity for a benchmark simple house model. The performance of the multithreading code shows favorable scalability properties and resource utilization, and much shorter execution time for large-scale power grid simulations.

  1. Differential mobility spectroscopy for chemical agent detection

    NASA Astrophysics Data System (ADS)

    Griffin, M. Todd

    2006-05-01

    General Dynamics ATP (GDATP) and Sionex Corporation (Sionex) are carrying out a cooperative development for a handheld chemical agent detector, being called JUNO TM, which will have lower false positives, higher sensitivity, and improved interference rejection compared with presently available detectors. This enhanced performance is made possible by the use of a new principle of ion separation called Differential Mobility Spectrometry (DMS). The enhanced selectivity is provided by the field tunable nature of the Sionex differential mobility technology (microDMxTM) which forms the analytical heart of the JUNO system and enables fingerprinting of molecules by characterization of the ionized molecular behavior under multiple electric field conditions. This enhanced selectivity is valuable in addressing not only the traditional list of chemical warfare agents (CWA) but also the substantial list of Toxic Industrial Compounds (TICs) and Toxic Industrial Materials (TIMs) which may be released in warfare or terrorist situations. Experimental results showing the ability of the microDMx to reject interferences, detect and resolve live agents are presented. An additional breakthrough in the technology was realized by operating the device at a reduced pressure of around 0.5 atmospheres. This reduced pressure operation resulted in roughly doubling the spectrometers resolution over what has previously been reported [1]. Advances have also been made in power consumption and packaging leading to a device suitable for portable, handheld, applications. Experimental results illustrating the performance of the microDMx technology employed in JUNO are highlighted.

  2. Investigation of statistics strategies for improving the discriminating power of laser-induced breakdown spectroscopy for chemical and biological warfare agent simulants

    NASA Astrophysics Data System (ADS)

    Munson, Chase A.; De Lucia, Frank C.; Piehler, Thuvan; McNesby, Kevin L.; Miziolek, Andrzej W.

    2005-08-01

    Laser-induced breakdown spectroscopy spectra of bacterial spores, molds, pollens and nerve agent simulants have been acquired. The performance of several statistical methodologies-linear correlation, principal components analysis, and soft independent model of class analogy-has been evaluated for their ability to differentiate between the various samples. The effect of data selection (total spectra, peak intensities, and intensity ratios) and pre-treatments (e.g., averaging) on the statistical models have also been studied. Results indicate the use of spectral averaging and weighting schemes may be used to significantly improve sample differentiation.

  3. In Vivo Efficacy of Human Simulated Regimens of Carbapenems and Comparator Agents against NDM-1-Producing Enterobacteriaceae

    PubMed Central

    Wiskirchen, Dora E.; Nordmann, Patrice; Crandon, Jared L.

    2014-01-01

    Doripenem and ertapenem have demonstrated efficacy against several NDM-1-producing isolates in vivo, despite having high MICs. In this study, we sought to further characterize the efficacy profiles of humanized regimens of standard (500 mg given every 8 h) and high-dose, prolonged infusion of doripenem (2 g given every 8 h, 4-h infusion) and 1 g of ertapenem given intravenously every 24 h and the comparator regimens of ceftazidime at 2 g given every 8 h (2-h infusion), levofloxacin at 500 mg every 24 h, and aztreonam at 2 g every 6 h (1-h infusion) against a wider range of isolates in a murine thigh infection model. An isogenic wild-type strain and NDM-1-producing Klebsiella pneumoniae and eight clinical NDM-1-producing members of the family Enterobacteriaceae were tested in immunocompetent- and neutropenic-mouse models. The wild-type strain was susceptible to all of the agents, while the isogenic NDM-1-producing strain was resistant to ceftazidime, doripenem, and ertapenem. Clinical NDM-1-producing strains were resistant to nearly all five of the agents (two were susceptible to levofloxacin). In immunocompetent mice, all of the agents produced ≥1-log10 CFU reductions of the isogenic wild-type and NDM-1-producing strains after 24 h. Minimal efficacy of ceftazidime, aztreonam, and levofloxacin against the clinical NDM-1-producing strains was observed. However, despite in vitro resistance, ≥1-log10 CFU reductions of six of eight clinical strains were achieved with high-dose, prolonged infusion of doripenem and ertapenem. Slight enhancements of doripenem activity over the standard doses were obtained with high-dose, prolonged infusion for three of the four isolates tested. Similar efficacy observations were noted in neutropenic mice. These data suggest that carbapenems are a viable treatment option for infections caused by NDM-1-producing Enterobacteriaceae. PMID:24379195

  4. Prediction of dual agents as an activator of mutant p53 and inhibitor of Hsp90 by docking, molecular dynamic simulation and virtual screening.

    PubMed

    Abbasi, Maryam; Sadeghi-Aliabadi, Hojjat; Hassanzadeh, Farshid; Amanlou, Massoud

    2015-09-01

    Heat shock protein90s (Hsp90s) play a crucial role in the development of cancer, and their inhibitors are a main target for tumor suppression. P53 also is a tumor suppressor, but in cancer cells, mutations in the p53 gene lead to the inactivation and accumulation of protein. For instance, the ninth p53 cancer mutation, Y220C, destabilizes the p53 core domain. Small molecules have been assumed to bind to Y220C DNA-binding domain and reactivate cellular mutant p53 functions. In this study, one of the mutant p53 activators is suggested as an Hsp90 inhibitor according to a pyrazole scaffold. To confirm a new ligand as a dual agent, molecular docking and molecular dynamic simulations were performed on both proteins (p53 and Hsp90). Molecular dynamic simulations were also conducted to evaluate the obtained results on the other two pyrazole structures, one known as Hsp90 inhibitor and the other as the reported mutant p53 activator. The findings indicate that the new ligand was stable in the active site of both proteins. Finally, a virtual screening was performed on ZINC database, and a set of new dual agents was proposed according to the new ligand scaffold. PMID:26277488

  5. Numerical Simulation of Evacuation Process in Malaysia By Using Distinct-Element-Method Based Multi-Agent Model

    NASA Astrophysics Data System (ADS)

    Abustan, M. S.; Rahman, N. A.; Gotoh, H.; Harada, E.; Talib, S. H. A.

    2016-07-01

    In Malaysia, not many researches on crowd evacuation simulation had been reported. Hence, the development of numerical crowd evacuation process by taking into account people behavioral patterns and psychological characteristics is crucial in Malaysia. On the other hand, tsunami disaster began to gain attention of Malaysian citizens after the 2004 Indian Ocean Tsunami that need quick evacuation process. In relation to the above circumstances, we have conducted simulations of tsunami evacuation process at the Miami Beach of Penang Island by using Distinct Element Method (DEM)-based crowd behavior simulator. The main objectives are to investigate and reproduce current conditions of evacuation process at the said locations under different hypothetical scenarios for the efficiency study of the evacuation. The sim-1 is initial condition of evacuation planning while sim-2 as improvement of evacuation planning by adding new evacuation area. From the simulation result, sim-2 have a shorter time of evacuation process compared to the sim-1. The evacuation time recuded 53 second. The effect of the additional evacuation place is confirmed from decreasing of the evacuation completion time. Simultaneously, the numerical simulation may be promoted as an effective tool in studying crowd evacuation process.

  6. Numerical simulation to study the feasibility of using CO2 as a stimulation agent for enhanced geothermal systems

    SciTech Connect

    Xu, T.; Zhang, W.; Pruess, K.

    2009-11-15

    A major concern in the development of enhanced geothermal systems (EGS) is achieving and maintaining adequate injectivity, while avoiding the development of preferential short-circuiting flow paths such as those caused by thermally-induced stress cracking. Past researches have tended to focus primarily on thermal and hydraulic stimulation. Recent studies suggest that chemical stimulation may improve the performance of EGS reservoirs. Geothermal injection wells are often drilled into formations containing reactive minerals such as calcite. Injecting aqueous chemical agents such as mineral acids, could be effective for mineral dissolution and porosity enhancement at distances of several meters around a well. An alternative to treatment with strong acids is the use of supercritical (SC) CO{sub 2} as stimulation agent for an aqueous-based EGS. Reactive transport modeling is used to investigate the effectiveness of this method. We used the thermal condition and mineralogical composition from a well of Desert Peak EGS site, to examine ways in which mixtures of water and CO{sub 2} can be injected to enhance porosity.

  7. Modeling the transmission of community-associated methicillin-resistant Staphylococcus aureus: a dynamic agent-based simulation

    PubMed Central

    2014-01-01

    Background Methicillin-resistant Staphylococcus aureus (MRSA) has been a deadly pathogen in healthcare settings since the 1960s, but MRSA epidemiology changed since 1990 with new genetically distinct strain types circulating among previously healthy people outside healthcare settings. Community-associated (CA) MRSA strains primarily cause skin and soft tissue infections, but may also cause life-threatening invasive infections. First seen in Australia and the U.S., it is a growing problem around the world. The U.S. has had the most widespread CA-MRSA epidemic, with strain type USA300 causing the great majority of infections. Individuals with either asymptomatic colonization or infection may transmit CA-MRSA to others, largely by skin-to-skin contact. Control measures have focused on hospital transmission. Limited public health education has focused on care for skin infections. Methods We developed a fine-grained agent-based model for Chicago to identify where to target interventions to reduce CA-MRSA transmission. An agent-based model allows us to represent heterogeneity in population behavior, locations and contact patterns that are highly relevant for CA-MRSA transmission and control. Drawing on nationally representative survey data, the model represents variation in sociodemographics, locations, behaviors, and physical contact patterns. Transmission probabilities are based on a comprehensive literature review. Results Over multiple 10-year runs with one-hour ticks, our model generates temporal and geographic trends in CA-MRSA incidence similar to Chicago from 2001 to 2010. On average, a majority of transmission events occurred in households, and colonized rather than infected agents were the source of the great majority (over 95%) of transmission events. The key findings are that infected people are not the primary source of spread. Rather, the far greater number of colonized individuals must be targeted to reduce transmission. Conclusions Our findings suggest

  8. Agent Orange

    MedlinePlus

    ... Index Agent Orange Agent Orange Home Facts about Herbicides Veterans' Diseases Birth Defects Benefits Exposure Locations Provider ... millions of gallons of Agent Orange and other herbicides on trees and vegetation during the Vietnam War. ...

  9. [Analytical and on-site detection methods for chemical warfare agents].

    PubMed

    Seto, Yasuo

    2006-12-01

    Chemical warfare agents (CWAs) are fast acting and sometimes lethal, even at low levels, and can be classified into nerve gases, blister agents, choking agents, blood agents, vomit agents, tear gases, and incapacitating agents. As countermeasures against CWA terrorism, detection and identification are important. In crisis management, monitoring of CWAs in public places and security checks at territorial borders, big event venues, and executive facilities are performed for protection against terrorism. In consequence management, on-site detection by first responders and laboratory analysis after on-site sampling and transfer are performed for minimization of terrorism damage, leading to personal protection, initial investigation, and emergency lifesaving. In incident management, laboratory analysis is performed to provide evidence at court trials for the prevention of future crimes. Laboratory analysis consists of pretreatment of on-site and casualty samples and instrumental analysis using GC-MS. However, CWAs are easily degraded, and thus are difficult to detect. Instead, it is useful to detect their metabolites and degradation products using tert-butyldimethylsilyl derivatization GC-MS or direct LC-MS. Commercially available chemical detection equipment such as gas detection tubes and ion mobility spectrometers are used for on-site detection. We have evaluated the detection performance of such equipment and found that no equipment fulfills the required perfect performance of CWA detection sensitivity, accuracy, response time, return time, and operation. To overcome the drawbacks, we have adopted the monitoring tape method and counterflow introduction atmospheric pressure chemical ionization mass spectrometry and recommend the combination of commercial detection equipment and these new technologies for simultaneous, rapid detection of all CWAs. PMID:17139154

  10. New simulation approach using classical formalism to water nuclear magnetic relaxation dispersions in presence of superparamagnetic particles used as MRI contrast agents

    NASA Astrophysics Data System (ADS)

    Vuong, Q. L.; Gossuin, Y.; Gillis, P.; Delangre, S.

    2012-09-01

    Superparamagnetic nanoparticles are used as negative contrast agents in magnetic resonance imaging: owing to their large magnetic moment the water proton spins are dephased, which accelerates the nuclear magnetic relaxation of an aqueous sample containing these particles. Transverse and longitudinal relaxation times depend on several parameters of the nanoparticles such as radius and magnetization and on experimental parameters such as the static magnetic field or echo time. In this work, we introduce a new simulation methodology, using a classical formalism, allowing the simulation of the NMR signal during transverse and longitudinal relaxation induced by superparamagnetic particles in an aqueous solution, which, to our knowledge has never been done before. Nuclear magnetic relaxation dispersion profiles are obtained for a wide range of nanoparticle radii and magnetizations. The results can be classified in two regimes—the well-known motional averaging and static regimes. This generalizes previous studies focusing on transverse relaxation at high magnetic field (larger than 1 T). Simulation results correspond to analytical theories in their validity range and so far unknown dependences of the relaxation with magnetization and radii of the NMR dispersions profiles are observed, which could be used to characterize experimental samples containing large superparamagnetic particles.

  11. Curcumin-I Knoevenagel's condensates and their Schiff's bases as anticancer agents: synthesis, pharmacological and simulation studies.

    PubMed

    Ali, Imran; Haque, Ashanul; Saleem, Kishwar; Hsieh, Ming Fa

    2013-07-01

    Pyrazolealdehydes (4a-d), Knoevenagel's condensates (5a-d) and Schiff's bases (6a-d) of curcumin-I were synthesized, purified and characterized. Hemolysis assays, cell line activities, DNA bindings and docking studies were carried out. These compounds were lesser hemolytic than standard drug doxorubicin. Minimum cell viability (MCF-7; wild) observed was 59% (1.0 μg/mL) whereas the DNA binding constants ranged from 1.4×10(3) to 8.1×10(5) M(-1). The docking energies varied from -7.30 to -13.4 kcal/mol. It has been observed that DNA-compound adducts were stabilized by three governing forces (Van der Wall's, H-bonding and electrostatic attractions). It has also been observed that compounds 4a-d preferred to enter minor groove while 5a-d and 6a-d interacted with major grooves of DNA. The anticancer activities of the reported compounds might be due to their interactions with DNA. These results indicated the bright future of the reported compounds as anticancer agents. PMID:23643901

  12. Preliminary evaluation of military, commercial and novel skin decontamination products against a chemical warfare agent simulant (methyl salicylate).

    PubMed

    Matar, Hazem; Guerreiro, Antonio; Piletsky, Sergey A; Price, Shirley C; Chilcott, Robert P

    2016-01-01

    Rapid decontamination is vital to alleviate adverse health effects following dermal exposure to hazardous materials. There is an abundance of materials and products which can be utilised to remove hazardous materials from the skin. In this study, a total of 15 products were evaluated, 10 of which were commercial or military products and five were novel (molecular imprinted) polymers. The efficacies of these products were evaluated against a 10 µl droplet of (14)C-methyl salicylate applied to the surface of porcine skin mounted on static diffusion cells. The current UK military decontaminant (Fuller's earth) performed well, retaining 83% of the dose over 24 h and served as a benchmark to compare with the other test products. The five most effective test products were Fuller's earth (the current UK military decontaminant), Fast-Act® and three novel polymers [based on itaconic acid, 2-trifluoromethylacrylic acid and N,N-methylenebis(acrylamide)]. Five products (medical moist-free wipes, 5% FloraFree™ solution, normal baby wipes, baby wipes for sensitive skin and Diphotérine™) enhanced the dermal absorption of (14)C-methyl salicylate. Further work is required to establish the performance of the most effective products identified in this study against chemical warfare agents. PMID:26339920

  13. Flow Cytometry with Gold Nanoparticles and their Clusters as scattering Contrast Agents: FDTD Simulation of Light-Cell Interaction

    PubMed Central

    Tanev, Stoyan; Sun, Wenbo; Pond, James; Tuchin, Valery V.; Zharov, Vladimir P.

    2010-01-01

    The formulation of the Finite-Difference Time-Domain (FDTD) approach is presented in the framework of its potential applications to in vivo flow cytometry based on light scattering. The consideration is focused on comparison of light scattering by a single biological cell alone in controlled refractive index matching conditions and by cells labeled by gold nanoparticles. The optical schematics including phase contrast (OPCM) microscopy as a prospective modality for in vivo flow cytometry is also analyzed. The validation of the FDTD approach for the simulation of flow cytometry may open a new avenue in the development of advanced cytometric techniques based on scattering effects from nanoscale targets. PMID:19670359

  14. Detection and classification characteristics of arrays of carbon black/organic polymer composite chemiresistive vapor detectors for the nerve agent simulants dimethylmethylphosphonate and diisopropylmethylphosponate.

    PubMed

    Hopkins, A R; Lewis, N S

    2001-03-01

    Arrays of conducting polymer composite vapor detectors have been evaluated for performance in the presence of the nerve agent simulants dimethylmethylphosphonate (DMMP) and diisopropylmethylphosponate (DIMP). Limits of detection for DMMP on unoptimized carbon black/ organic polymer composite vapor detectors in laboratory air were estimated to be 0.047-0.24 mg m(-3). These values are lower than the EC50 value (where EC50 is the airborne concentration sufficient to induce severe effects in 50% of those exposed for 30 min) for the nerve agents sarin (methylphosphonofluoridic acid, 1-methylethyl ester) and soman (methylphosphonofluoridic acid, 1,2,2-trimethylpropyl ester), which has been established as approximately 0.8 mg m(-3). Arrays of these vapor detectors were easily able to resolve signatures due to exposures to DMMP from those due to DIMP or due to a variety of other test analytes (including water, methanol, benzene, toluene, diesel fuel, lighter fluid, vinegar, and tetrahydrofuran) in a laboratory air background. In addition, DMMP at 27 mg m(-3) could be detected and differentiated from the signatures of the other test analytes in the presence of backgrounds of potential interferences, including water, methanol, benzene, toluene, diesel fuel, lighter fluid, vinegar, and tetrahydrofuran, even when these interferents were present in much higher concentrations than that of the DMMP or DIMP being detected. PMID:11289432

  15. Monte Carlo simulation of microbeam radiation therapy with an interlaced irradiation geometry and an Au contrast agent in a realistic head phantom

    NASA Astrophysics Data System (ADS)

    Gokeri, Gurdal; Kocar, Cemil; Tombakoglu, Mehmet

    2010-12-01

    In this study, dose distribution calculations for bidirectional interlaced microbeam radiation therapy (BIMRT) were performed with a detailed head phantom model and the Monte Carlo code MCNPX. Doses were calculated in intracranial targets of dimensions 20 × 6.8 × 20 mm3 and 20 × 20 × 20 mm3 and surrounding tissue for which interlacing arrays are composed of 5 and 15 microbeams, respectively. Simulations were performed with a realistic head phantom and a homogenized head phantom of the same outer shape to study the effects of the structure of the realistic phantom on dose distribution and to show how important it is to use realistic phantoms. Depth-dose profiles and dose falloffs at the edges of the targets were calculated for cases with and without an Au contrast agent deposited in the target region and surrounding tissue. The parallel pattern of the microbeam arrays was preserved through the head phantom which makes it possible to interlace microbeam arrays even at deep seated targets. As the dimensions of the target volume were increased, the valley dose values increased with the number of microbeams. This sets limits on the size and position of the target. The usage of gold as a contrast agent provided a substantial increase in target dose and decreased the skin entrance, maximum skull bone and maximum brain doses inevitable to produce the desired target dose. Short dose falloffs at the edges of the targets were preserved for all cases.

  16. Detection and classification characteristics of arrays of carbon black/organic polymer composite chemiresistive vapor detectors for the nerve agent simulants Dimethylmethylphosphonate and Diisopropy

    NASA Astrophysics Data System (ADS)

    Hopkins, Alan R.; Lewis, Nathan S.

    2002-06-01

    Arrays of conducting polymer composite vapor detectors have been evaluated for performance in the presence of the nerve agent simulants dimethylmethylphosphonate (DMMP) and diisopropylmethylphosponate (DIMP). Limits of detection for DMMP on unoptimized carbon black-organic polymer composite vapor detectors in laboratory air were estimated to be 0.047-0.24 mg m-3. These values are lower than the EC50 value for the nerve agents sarin (methylphosphonofluoridic acid, (1-methylethyl) ester) and soman, which have been established as equals 0.8 mg m-3. Arrays of these vapor detectors were easily able to resolve signatures due to exposures to DMMP from those due to DIMP or due to a variety of other test analytes in a laboratory air background. In addition, DMMP at 27 mg m-3 could be detected and differentiated from the signatures of the other test analytes in the presence of backgrounds of potential interferents in the background ambient, including water, methanol, benzene, toluene, diesel fuel, lighter fluid, vinegar and tetrahydrofuran, even when these interferents were present in much higher concentrations than that of the DMMP or DIMP being detected.

  17. Compatibility and stability of palonosetron hydrochloride with four neruomuscular blocking agents during simulated y-site administration.

    PubMed

    Trusley, Craig; Ben, Michael; Kupiec, Thomas C; Trissel, Lawrence A

    2008-01-01

    Palonosetron hydrochloride is a longer-acting selective 5-HT3 receptor antagonist that has been approved for the prevention of chemotherapy-induced nausea and vomiting and is being evaluated for the prevention of postoperative nausea and vomiting. The objective of this study was to evaluate the physical and chemical stability of palonosetron hydrochloride 50 mcg/mL when mixed with any of the neuromuscular blocking drugs cisatracurium besylate 0.5 mg/mL, rocuronium bromide 1 mg/mL, succinylcholine chloride 2 mg/mL, and vecuronium bromide 1 mg/mL during simulated Y-site administration. Triplicate samples of palonosetron hydrochloride with each of the neuromuscular blocking drugs were tested. Samples were stored and evaluated for up to 4 hours at room temperature. Physical stability was assessed by turbidimetric and particulate measurements and visual inspection. Chemical stability was assessed by high-performnace liquid chromatography. All of the admixtures were clear and colorless when viewed in normal fluorescent room light and when viewed with a Tyndall beam. Measured turbidity and particulate content were low initially and remained low throughout the study. The drug concentration was unchanged in all of the samples tested. Palonosetron hydrochloride is physically and chemically stable with cisatracurium besylate, rocuronium bromide, succinylcholine chloride, or vecuronium bromide at the concentrations tested during simulated Y-site administration over 4 hours at ambient room temperature. PMID:23969608

  18. Portable Solid Phase Micro-Extraction Coupled with Ion Mobility Spectrometry System for On-Site Analysis of Chemical Warfare Agents and Simulants in Water Samples

    PubMed Central

    Yang, Liu; Han, Qiang; Cao, Shuya; Yang, Jie; Yang, Junchao; Ding, Mingyu

    2014-01-01

    On-site analysis is an efficient approach to facilitate analysis at the location of the system under investigation as it can result in more accurate, more precise and quickly available analytical data. In our work, a novel self-made thermal desorption based interface was fabricated to couple solid-phase microextraction with ion mobility spectrometry for on-site water analysis. The portable interface can be connected with the front-end of an ion mobility spectrometer directly without other modifications. The analytical performance was evaluated via the extraction of chemical warfare agents and simulants in water samples. Several parameters including ionic strength and extraction time have been investigated in detail. The application of the developed method afforded satisfactory recoveries ranging from 72.9% to 114.4% when applied to the analysis of real water samples. PMID:25384006

  19. Numerical simulation study of silica and calcite dissolution around a geothermal well by injecting high pH solutions with chelating agent.

    SciTech Connect

    Xu, Tianfu; Rose, Peter; Fayer, Scott; Pruess, Karsten

    2009-02-01

    Dissolution of silica, silicate, and calcite minerals in the presence of a chelating agent (NTA) at a high pH has been successfully performed in the laboratory using a high-temperature flow reactor. The mineral dissolution and porosity enhancement in the laboratory experiment has been reproduced by reactive transport simulation using TOUGHREACT. The chemical stimulation method has been applied by numerical modeling to a field geothermal injection well system, to investigate its effectiveness. Parameters from the quartz monzodiorite unit at the Enhanced Geothermal System (EGS) site at Desert Peak (Nevada) were used. Results indicate that the injection of a high pH chelating solution results in dissolution of both calcite and plagioclase minerals, and avoids precipitation of calcite at high temperature conditions. Consequently reservoir porosity and permeability can be enhanced especially near the injection well.

  20. Chromatographic separation of simulants of nerve and blister agents by combining one- and two-channel columns with different stationary phases.

    PubMed

    Yuan, Huan; Du, Xiaosong; Li, Yi; Zhao, Xulan; Xu, Ming

    2016-04-01

    A two-channel gas chromatography column and a single-channel column were made by deep reactive-ion etching technology. The two short columns were coated with different stationary phases, and then linked without a modulator. This is to aim at increasing the sample capacity and achieving a higher separation efficiency in complex environments. The results show that the capacity of the connected column is approximately 4 and 1.5 times larger than that of the single- and two-channel columns, respectively. The linked column was utilized to separate a six-component mixture, composed of three simulants of nerve and blister agents and three interfering vapors. The results demonstrate that the combined column has a remarkably higher separation efficiency than the individual columns, and an acceptable resolution is achieved although the total length of the linked column is only 1.5 m. PMID:26843525

  1. Portable solid phase micro-extraction coupled with ion mobility spectrometry system for on-site analysis of chemical warfare agents and simulants in water samples.

    PubMed

    Yang, Liu; Han, Qiang; Cao, Shuya; Yang, Jie; Yang, Junchao; Ding, Mingyu

    2014-01-01

    On-site analysis is an efficient approach to facilitate analysis at the location of the system under investigation as it can result in more accurate, more precise and quickly available analytical data. In our work, a novel self-made thermal desorption based interface was fabricated to couple solid-phase microextraction with ion mobility spectrometry for on-site water analysis. The portable interface can be connected with the front-end of an ion mobility spectrometer directly without other modifications. The analytical performance was evaluated via the extraction of chemical warfare agents and simulants in water samples. Several parameters including ionic strength and extraction time have been investigated in detail. The application of the developed method afforded satisfactory recoveries ranging from 72.9% to 114.4% when applied to the analysis of real water samples. PMID:25384006

  2. Ideal free distribution or dynamic game? An agent-based simulation study of trawling strategies with varying information

    NASA Astrophysics Data System (ADS)

    Beecham, J. A.; Engelhard, G. H.

    2007-10-01

    An ecological economic model of trawling is presented to demonstrate the effect of trawling location choice strategy on net input (rate of economic gain of fish caught per time spent less costs). Fishing location choice is considered to be a dynamic process whereby trawlers chose from among a repertoire of plastic strategies that they modify if their gains fall below a fixed proportion of the mean gains of the fleet as a whole. The distribution of fishing across different areas of a fishery follows an approximate ideal free distribution (IFD) with varying noise due to uncertainty. The least-productive areas are not utilised because initial net input never reaches the mean yield of better areas subject to competitive exploitation. In cases, where there is a weak temporal autocorrelation between fish stocks in a specific location, a plastic strategy of local translocation between trawls mixed with longer-range translocation increases realised input. The trawler can change its translocation strategy in the light of information about recent trawling success compared to its long-term average but, in contrast to predictions of the Marginal Value Theorem (MVT) model, does not know for certain what it will find by moving, so may need to sample new patches. The combination of the two types of translocation mirrored beam-trawling strategies used by the Dutch fleet and the resultant distribution of trawling effort is confirmed by analysis of historical effort distribution of British otter trawling fleets in the North Sea. Fisheries exploitation represents an area where dynamic agent-based adaptive models may be a better representation of the economic dynamics of a fleet than classically inspired optimisation models.

  3. Chemical defense collective protection technology. Volume 12. A procedure for recharging self-contained breathing apparatus air bottles in the presence of simulated chemical warfare agents. Final report, 6-11 September 1990

    SciTech Connect

    Conkle, J.P.; Tucker, D.M.; Moore, G.

    1993-05-01

    A procedure was developed and tested for recharging Self-Contained Breathing Apparatus (SCBA) cylinders in an atmosphere contaminated with chemical agent simulant at concentrations which would produce casualties if actual agent were used. With the exception of a rack for storing the cylinders before and after recharging, all items used are currently available commercially or through off-the-shelf DOD supply sources. Cylinders were successfully recharged without contamination in the presence of chemical agent simulant in the compressor area as well as in the cylinder filling area. Inexperienced personnel easily learned and successfully followed the recharging procedures even though they were burdened by protective clothing and equipment. Chemical agents, SCBA, Firefighting, Self-contained breathing apparatus.

  4. Aging of polyurethane foam insulation in simulated refrigerator panels -- Initial results with third-generation blowing agents

    SciTech Connect

    Wilkes, K.E.; Gabbard, W.A.; Weaver, F.J.

    1998-11-01

    Laboratory data are presented on the effect of constant-temperature aging on the apparent thermal conductivity of polyurethane foam insulation for refrigerators and freezers. The foam specimens were blown with HCFC-141b and with three of its potential replacements -- HFC-134a, HFC-245fa, and cyclopentane. Specimens were aged at constant temperatures of 90 F, 40 F, and {minus}10 F. Thermal conductivity measurements were made on two types of specimens: full-thickness simulated refrigerator panels containing foam enclosed between solid plastic sheets, and thin slices of core foam cut from similar panels. Results are presented for about 250 days of aging for the core-foam specimens and for the first six months of aging for the full-thickness panels.

  5. Flow cytometry with gold nanoparticles and their clusters as scattering contrast agents: FDTD simulation of light-cell interaction.

    PubMed

    Tanev, Stoyan; Sun, Wenbo; Pond, James; Tuchin, Valery V; Zharov, Vladimir P

    2009-09-01

    The formulation of the finite-difference time-domain (FDTD) approach is presented in the framework of its potential applications to in-vivo flow cytometry based on light scattering. The consideration is focused on comparison of light scattering by a single biological cell alone in controlled refractive-index matching conditions and by cells labeled by gold nanoparticles. The optical schematics including phase contrast (OPCM) microscopy as a prospective modality for in-vivo flow cytometry is also analyzed. The validation of the FDTD approach for the simulation of flow cytometry may open up a new avenue in the development of advanced cytometric techniques based on scattering effects from nanoscale targets. PMID:19670359

  6. Aging of Polyurethane Foam Insulation in Simulated Refrigerator Panels--One-Year Results with Third-Generation Blowing Agents

    SciTech Connect

    Gabbard, W.A.; Weaver, F.J.; Wilkes, K.E.

    1999-09-27

    Laboratory data are presented on the effect of constant-temperature aging on the apparent thermal conductivity of polyurethane foam insulation for refrigerators and freezers. The foam specimens were blown with HCFC-141b and with three of its potential replacements--HFC-134a, HFC-245fa, and cyclopentane. Specimens were aged at constant temperatures of 90 F, 40 F, and {minus}10 F. Thermal conductivity measurements were made on two types of specimens: full-thickness simulated refrigerator panels containing foam enclosed between solid plastic sheets, and thin slices of core foam cut from similar panels. Results are presented for the first year of a multi-year study for the full-thickness panels and for about 1-1/2 years of aging for the core-foam specimens.

  7. Aging of Polyurethane Foam Insulation in Simulated Refrigerator Panels--Three-Year Results with Third-Generation Blowing Agents

    SciTech Connect

    Wilkes, K.E.

    2001-05-29

    Laboratory data are presented on the effect of constant-temperature aging on the apparent thermal conductivity of polyurethane foam insulation for refrigerators and freezers. The foam specimens were blown with HCFC-141b and with three of its potential replacements--HFC-134a, HFC-245fa, and cyclopentane. Specimens were aged at constant temperatures of 90 F, 40 F, and -10 F. Thermal conductivity measurements were made on two types of specimens: full-thickness simulated refrigerator panels containing foam enclosed between solid plastic sheets, and thin slices of core foam cut from similar panels. Results are presented for the first three years of a multi-year aging study. Preliminary comparisons of measured data with predictions of a mathematical aging model are presented.

  8. Multi-agent modeling and simulation of farmland use change in the farming-pastoral zone: A case study of Qianjingou Town in Inner Mongolia, China

    NASA Astrophysics Data System (ADS)

    Yan, H.

    2015-12-01

    Farmland is the most basic material conditions for guaranteeing rural livelihoods and national food security, and exploring management strategies that take both of the sustainable rural livelihoods and sustainable farmland use into account has vital significance of theory and practice. Farmland is a complex and self-adaptive system that couples human and natural systems together, and natural factors and social factors that are related to its changing process need to be considered when modeling farmland changing process. This paper takes Qianjingou Town in Inner Mongolia farming-pastoral zone as study area. From the perspective of the relationship between households' livelihoods and farmland use, this study builds the process mechanism of farmland use change based on questionnaires data, and constructs multi-agent simulation model of farmland use change with the help of Eclipse and Repast toolbox. Through simulating the relationship between natural factors (with geographical location) and households' behaviors, this paper systematically simulates households' renting and abandoning farmland behaviors, and truly describes dynamic interactions between households' livelihoods and factors related to farmland use change. These factors include natural factors (net primary productivity, road accessibility, slope and relief amplitude) and social factors (households' family structures, economic development and government policies). In the end, this study scientifically predicts farmland use change trend in the future 30 years. The simulation results show that, the number of abandoned and sublet farmland plots has a gradually increasing trend, the number of non-farm households and pure-outwork households has a remarkable increasing trend, and the number of part-farm households and pure-farm households shows a decreasing trend. Households' livelihoods sustainability in the study area is confronted with increasing pressure, and households' nonfarm employment has an increasing

  9. Detection of nerve agents using proton transfer reaction mass spectrometry with ammonia as reagent gas.

    PubMed

    Ringer, Joachim M

    2013-01-01

    The chemical warfare agents (CWA) Sarin, Soman, Cyclosarin and Tabun were characterised by proton transfer mass spectrometry (PTRMS). It was found that PTRMS is a suitable technique to detect nerve agents highly sensitively, highly selectively and in near real-time. Methods were found to suppress molecule fragmentation which is significant under PTRMS hollow cathode ionisation conditions. In this context, the drift voltage (as one of the most important system parameters) was varied and ammonia was introduced as an additional chemical reagent gas. Auxiliary chemicals such as ammonia affect ionisation processes and are quite common in context with detectors for CWAs based on ion mobility spectrometry (IMS). With both, variation of drift voltage and ammonia as the reagent gas, fragmentation can be suppressed effectively. Suppression of fragmentation is crucial particularly concerning the implementation of an algorithm for automated agent identification in field applications. On the other hand, appearance of particular fragments might deliver additional information. Degradation and rearrangement products of nerve agents are not distinctive for the particular agent but for the chemical class they belong to. It was found that switching between ammonia doped and ordinary water ionisation chemistry can easily be performed within a few seconds. Making use of this effect it is possible to switch between fragment and molecular ion peak spectra. Thus, targeted fragmentation can be used to confirm identification based only on single peak detection. PTRMS turned out to be a promising technique for future CWA detectors. In terms of sensitivity, response time and selectivity (or confidence of identification, respectively) PTRMS performs as a bridging technique between IMS and GC-MS. PMID:24308198

  10. Use of an agent-based simulation model to evaluate a mobile-based system for supporting emergency evacuation decision making.

    PubMed

    Tian, Yu; Zhou, Tian-Shu; Yao, Qin; Zhang, Mao; Li, Jing-Song

    2014-12-01

    Recently, mass casualty incidents (MCIs) have been occurring frequently and have gained international attention. There is an urgent need for scientifically proven and effective emergency responses to MCIs, particularly as the severity of incidents is continuously increasing. The emergency response to MCIs is a multi-dimensional and multi-participant dynamic process that changes in real-time. The evacuation decisions that assign casualties to different hospitals in a region are very important and impact both the results of emergency treatment and the efficiency of medical resource utilization. Previously, decisions related to casualty evacuation were made by an incident commander with emergency experience and in accordance with macro emergency guidelines. There are few decision-supporting tools available to reduce the difficulty and psychological pressure associated with the evacuation decisions an incident commander must make. In this study, we have designed a mobile-based system to collect medical and temporal data produced during an emergency response to an MCI. Using this information, our system's decision-making model can provide personal evacuation suggestions that improve the overall outcome of an emergency response. The effectiveness of our system in reducing overall mortality has been validated by an agent-based simulation model established to simulate an emergency response to an MCI. PMID:25354665

  11. Biological Agents

    MedlinePlus

    ... to Z Index Contact Us FAQs What's New Biological Agents This page requires that javascript be enabled ... and Health Topics A-Z Index What's New Biological agents include bacteria, viruses, fungi, other microorganisms and ...

  12. Relative merits of rCWA and XiX heteronuclear spin decoupling in solid-state magic-angle-spinning NMR spectroscopy: A bimodal Floquet analysis

    NASA Astrophysics Data System (ADS)

    Equbal, Asif; Leskes, Michal; Nielsen, Niels Chr.; Madhu, P. K.; Vega, Shimon

    2016-02-01

    We present a bimodal Floquet analysis of the recently introduced refocused continuous wave (rCW) solid-state NMR heteronuclear dipolar decoupling method and compare it with the similar looking X-inverse X (XiX) scheme. The description is formulated in the rf interaction frame and is valid for both finite and ideal π pulse rCW irradiation that forms the refocusing element in the rCW scheme. The effective heteronuclear dipolar coupling Hamiltonian up to first order is described. The analysis delineates the difference between the two sequences to different orders of their Hamiltonians for both diagonal and off-diagonal parts. All the resonance conditions observed in experiments and simulations have been characterised and their influence on residual line broadening is highlighted. The theoretical comparison substantiates the numerical simulations and experimental results to a large extent.

  13. Effect of long-term simulated pulpal pressure on the bond strength and nanoleakage of resin-luting agents with different bonding strategies.

    PubMed

    de Alexandre, R S; Santana, V B; Kasaz, A C; Arrais, C A G; Rodrigues, J A; Reis, A F

    2014-01-01

    This study evaluated the effects of simulated hydrostatic pulpal pressure (SPP) on the microtensile bond strength (μTBS) to dentin and nanoleakage patterns produced by self-adhesive luting agents after 12 months. Three self-adhesive luting agents (RelyX Unicem [UN], RelyX U100 [UC], and Clearfil SA Luting [SA]) and three conventional luting agents (Rely X ARC [RX], Panavia F [PF], and a two-step self-etching adhesive system [Clearfil SE Bond] associated with Panavia F [PS]) were evaluated. One hundred twenty-three human molars were abraded to expose occlusal surfaces. Resin cements were used to lute cylindrical composite blocks to the teeth either subjected or not to SPP. Sixty specimens were subjected to 15 cm H2O of SPP for 24 hours before and 24 hours or 12 months after cementation procedures. Afterward, restored teeth were serially sectioned into beams with a cross-sectional area of 1 mm(2) at the bonded interface and were tested in tension (cross-head speed of 1 mm/min). Failure mode was determined using scanning electron microscopy (SEM). Data were statistically analyzed by three-way analysis of variance and post hoc Tukey test (p=0.05). Two additional teeth in each group were serially sectioned into 0.9-mm-thick slabs, which were submitted to a nanoleakage protocol with AgNO3 and analyzed with scanning and transmission electron microscopes. The μTBS values of the etch-and-rinse group (RX) were negatively influenced by SPP and long-term water storage with SPP. After 12 months, UC and SA presented premature failures in all specimens when submitted to SPP. SPP increased silver deposition in most groups in both evaluation times. The hydrostatic pulpal pressure effect was material dependent. The storage time without SPP did not affect bond strength. However, long-term SPP influenced the performance of the etch-and-rinse and self-adhesive cements regarding μTBS and nanoleakage pattern, except to UN. PMID:24502755

  14. Effect of Food Simulating Agents on the Hardness and Bond Strength of a Silicone Soft Liner to a Denture Base Acrylic Resin

    PubMed Central

    Khaledi, A.A.R.; Bahrani, M.; Shirzadi, S.

    2015-01-01

    Statement of the Problem: Bonding failure between acrylic resin and soft liner material and also gradual loss of soft liner resiliency over time are two impending challenges frequently recognized with a denture base embraced with a resilient liner. Since patients drink various beverages, it is crucial to assess the influences of these beverages on physical characteristics of soft liners. Purpose: This in vitro study envisioned to assess the influence of food simulating agents (FSA) on the hardness of a silicone soft liner by employing a Shore A durometer test and also evaluate its bond strength to a denture base resin by using tensile bond strength test. Materials and Methods: To test the hardness of samples, 50 rectangular samples (40 mm × 10 mm × 3 mm) were prepared from a heat-polymerized polymethyl methacrylate (Meliodent). Mollosil, a commercially available silicone resilient liner, was provided and applied on the specimens following the manufacturer’s directions. In order to test tensile bond strength, 100 cylindrical specimens (30 mm × 10 mm) were fabricated. The liners were added between specimens with the thicknesses of 3 mm. The specimens were divided into 5 groups (n=10) and immersed in distilled water, heptane, citric acid, and 50% ethanol. For each test, we used 10 specimens as a baseline measurement; control group. All specimens were kept in dispersed containers at 37ºC for 12 days and all solutions were changed every day. The hardness was verified using a Shore A durometer and the tensile bond strength was examined by an Instron testing machine at a cross-head speed of 5 mm/min. The records were analyzed employing one-way ANOVA, Tukey’s HSD, and LSD tests. Results: The mean tensile bond strength ± standard deviation (SD) for Mollosil was as follows for each group: 3.1 ± 0.4 (water), 1.8 ± 0.4 (citric acid), 3.0 ± 0.4 (heptane), 1.2 ± 0.3 (50% ethanol), and 3.8 ± 0.4 (control). The hardness values for each group were: 28.7 ± 2.11 (water

  15. Continuum Model for Decontamination of Chemical Warfare Agent from a Rubbery Polymer using the Maxwell-Stefan Formulation

    NASA Astrophysics Data System (ADS)

    Varady, Mark; Bringuier, Stefan; Pearl, Thomas; Stevenson, Shawn; Mantooth, Brent

    Decontamination of polymers exposed to chemical warfare agents (CWA) often proceeds by application of a liquid solution. Absorption of some decontaminant components proceed concurrently with extraction of the CWA, resulting in multicomponent diffusion in the polymer. In this work, the Maxwell-Stefan equations were used with the Flory-Huggins model of species activity to mathematically describe the transport of two species within a polymer. This model was used to predict the extraction of the nerve agent O-ethyl S-[2(diisopropylamino)ethyl] methylphosphonothioate (VX) from a silicone elastomer into both water and methanol. Comparisons with experimental results show good agreement with minimal fitting of model parameters from pure component uptake data. Reaction of the extracted VX with sodium hydroxide in the liquid-phase was also modeled and used to predict the overall rate of destruction of VX. Although the reaction proceeds more slowly in the methanol-based solution compared to the aqueous solution, the extraction rate is faster due to increasing VX mobility as methanol absorbs into the silicone, resulting in an overall faster rate of VX destruction.

  16. Computational Fluid Dynamics Simulations of Contrast Agent Bolus Dispersion in a Coronary Bifurcation: Impact on MRI-Based Quantification of Myocardial Perfusion

    PubMed Central

    Schmidt, Regine; Graafen, Dirk; Weber, Stefan; Schreiber, Laura M.

    2013-01-01

    Contrast-enhanced first-pass magnetic resonance imaging (MRI) in combination with a tracer kinetic model, for example, MMID4, can be used to determine myocardial blood flow (MBF) and myocardial perfusion reserve (MPR). Typically, the arterial input function (AIF) required for this methodology is estimated from the left ventricle (LV). Dispersion of the contrast agent bolus might occur between the LV and the myocardial tissue. Negligence of bolus dispersion could cause an error in MBF determination. The aim of this study was to investigate the influence of bolus dispersion in a simplified coronary bifurcation geometry including one healthy and one stenotic branch on the quantification of MBF and MPR. Computational fluid dynamics (CFD) simulations were combined with MMID4. Different inlet boundary conditions describing pulsatile and constant flows for rest and hyperemia and differing outflow conditions have been investigated. In the bifurcation region, the increase of the dispersion was smaller than inside the straight vessels. A systematic underestimation of MBF values up to −16.1% for pulsatile flow and an overestimation of MPR up to 7.5% were found. It was shown that, under the conditions considered in this study, bolus dispersion can significantly influence the results of quantitative myocardial MR-perfusion measurements. PMID:23533541

  17. Multi-Agent Social Simulation

    NASA Astrophysics Data System (ADS)

    Noda, Itsuki; Stone, Peter; Yamashita, Tomohisa; Kurumatani, Koichi

    While ambient intelligence and smart environments (AISE) technologies are expected to provide large impacts to human lives and social activities, it is generally difficult to show utilities and effects of these technologies on societies. AISE technologies are not only methods to improve performance and functionality of existing services in the society, but also frameworks to introduce new systems and services to the society. For example, no one expected beforehand what Internet or mobile phone brought into out social activities and services, although they changes our social system and patterns of behaviors drastically and emerge new services (and risks, unfortunately). The main reason of this difficulty is that actual effects of IT systems appear when enough number of people in the society use the technologies.

  18. Modeling the 2014 Ebola Virus Epidemic – Agent-Based Simulations, Temporal Analysis and Future Predictions for Liberia and Sierra Leone

    PubMed Central

    Siettos, Constantinos; Anastassopoulou, Cleo; Russo, Lucia; Grigoras, Christos; Mylonakis, Eleftherios

    2015-01-01

    We developed an agent-based model to investigate the epidemic dynamics of Ebola virus disease (EVD) in Liberia and Sierra Leone from May 27 to December 21, 2014. The dynamics of the agent-based simulator evolve on small-world transmission networks of sizes equal to the population of each country, with adjustable densities to account for the effects of public health intervention policies and individual behavioral responses to the evolving epidemic. Based on time series of the official case counts from the World Health Organization (WHO), we provide estimates for key epidemiological variables by employing the so-called Equation-Free approach. The underlying transmission networks were characterized by rather random structures in the two countries with densities decreasing by ~19% from the early (May 27-early August) to the last period (mid October-December 21). Our estimates for the values of key epidemiological variables, such as the mean time to death, recovery and the case fatality rate, are very close to the ones reported by the WHO Ebola response team during the early period of the epidemic (until September 14) that were calculated based on clinical data. Specifically, regarding the effective reproductive number Re, our analysis suggests that until mid October, Re was above 2.3 in both countries; from mid October to December 21, Re dropped well below unity in Liberia, indicating a saturation of the epidemic, while in Sierra Leone it was around 1.9, indicating an ongoing epidemic. Accordingly, a ten-week projection from December 21 estimated that the epidemic will fade out in Liberia in early March; in contrast, our results flashed a note of caution for Sierra Leone since the cumulative number of cases could reach as high as 18,000, and the number of deaths might exceed 5,000, by early March 2015. However, by processing the reported data of the very last period (December 21, 2014-January 18, 2015), we obtained more optimistic estimates indicative of a remission of

  19. Preliminary effects of real-world factors on the recovery and exploitation of forensic impurity profiles of a nerve-agent simulant from office media.

    PubMed

    Fraga, Carlos G; Sego, Landon H; Hoggard, Jamin C; Acosta, Gabriel A Pérez; Viglino, Emilie A; Wahl, Jon H; Synovec, Robert E

    2012-12-28

    Dimethyl methylphosphonate (DMMP) was used as a chemical threat agent (CTA) simulant for a first look at the effects of real-world factors on the recovery and exploitation of a CTA's impurity profile for source matching. Four stocks of DMMP having different impurity profiles were disseminated as aerosols onto cotton, painted wall board, and nylon coupons according to a thorough experimental design. The DMMP-exposed coupons were then solvent extracted and analyzed for DMMP impurities by comprehensive 2D gas chromatography/mass spectrometry (GC×GC/MS). The similarities between the coupon DMMP impurity profiles and the known (reference) DMMP profiles were measured by dot products of the coupon profiles and known profiles and by score values obtained from principal component analysis. One stock, with a high impurity-profile selectivity value of 0.9 out of 1, had 100% of its respective coupons correctly classified and no false positives from other coupons. Coupons from the other three stocks with low selectivity values (0.0073, 0.012, and 0.018) could not be sufficiently distinguished from one another for reliable matching to their respective stocks. The results from this work support that: (1) extraction solvents, if not appropriately selected, can have some of the same impurities present in a CTA reducing a CTA's useable impurity profile, (2) low selectivity among a CTA's known impurity profiles will likely make definitive source matching impossible in some real-world conditions, (3) no detrimental chemical-matrix interference was encountered during the analysis of actual office media, (4) a short elapsed time between release and sample storage is advantageous for the recovery of the impurity profile because it minimizes volatilization of forensic impurities, and (5) forensic impurity profiles weighted toward higher volatility impurities are more likely to be altered by volatilization following CTA exposure. PMID:23177156

  20. Preliminary Effects of Real-World Factors on the Recovery and Exploitation of Forensic Impurity Profiles of a Nerve-Agent Simulant from Office Media

    SciTech Connect

    Fraga, Carlos G.; Sego, Landon H.; Hoggard, Jamin C.; Perez Acosta, Gabriel A.; Viglino, Emilie A.; Wahl, Jon H.; Synovec, Robert E.

    2012-12-28

    Dimethyl methylphosphonate (DMMP) was used as a chemical threat agent (CTA) simulant for a first look at the effects of real-world factors on the recovery and exploitation of a CTA’s impurity profile for source matching. Four stocks of DMMP having different impurity profiles were disseminated as aerosols onto cotton, painted wall board, and nylon coupons according to a thorough experimental design. The DMMP-exposed coupons were then solvent extracted and analyzed for DMMP impurities by comprehensive 2-D gas chromatography/mass spectrometry (GC×GC/MS). The similarities between the coupon DMMP impurity profiles and the known (reference) DMMP profiles were measured by dot products of the coupon profiles and known profiles and by score values obtained from principal component analysis. One stock, with a high impurity-profile selectivity value of 0.9 out of 1, had 100% of its respective coupons correctly classified and no false positives from other coupons. Coupons from the other three stocks with low selectivity values (0.0073, 0.012, and 0.018) could not be sufficiently distinguished from one another for reliable matching to their respective stocks. The results from this work support that: (1) extraction solvents, if not appropriately selected, can have some of the same impurities present in a CTA reducing a CTA’s useable impurity profile, (2) low selectivity among a CTA’s known impurity profiles will likely make definitive source matching impossible in some real-world conditions, (3) no detrimental chemical-matrix interference was encountered during the analysis of actual office media, (4) a short elapsed time between release and sample storage is advantageous for the recovery of the impurity profile because it minimizes volatilization of forensic impurities, and (5) forensic impurity profiles weighted towards higher volatility impurities are more likely to be altered by volatilization following CTA exposure.

  1. Vapour breakthrough behaviour of carbon tetrachloride - A simulant for chemical warfare agent on ASZMT carbon: A comparative study with whetlerite carbon

    NASA Astrophysics Data System (ADS)

    Srivastava, Avanish Kumar; Shah, Dilip K.; Mahato, T. H.; Roy, A.; Yadav, S. S.; Srivas, S. K.; Singh, Beer

    2013-06-01

    ASZMT and whetlerite carbon was prepared by impregnation of active carbon with ammonical salts of Cu (II), Ag (I), Zn (II), Mo (VI), TEDA and Cu (II), Ag (I), Cr (VI), NaOH, C5H5N respectively using incipient wetness technique. Thereafter, impregnated carbon systems were characterized using scanning electron microscopy, energy dispersive X-ray, atomic absorption spectroscopy, thermogravimetry and surface characterization techniques. Impregnated carbon systems were evaluated under dynamic conditions against carbon tetrachloride (CCl4) vapour that was used as a simulant for the persistent chemical warfare agents for testing breakthrough times of filter cartridges and canisters of gas masks in the national approval test of respirators. The protective potential of ASZMT carbon was compared with the whetlerite carbon which is presently used in NBC filtration system. The effect of CCl4 concentration, test flow rate, temperature and relative humidity on the breakthrough behaviour of the impregnated carbon systems has also been studied. The study clearly indicated that the whetlerite carbon possessed breakthrough time greater than ASZMT carbon. However, ASZMT carbon provided adequate protection against CCl4 vapours and can be used as an alternative to whetlerite carbon that contain Cr(VI), which is reported to be carcinogenic and having lesser shelf life. The study indicated the breakthrough time of impregnated carbon systems were found to decrease with the increase of the CCl4 concentration and flow rate. The variation in temperature and relative humidity did not significantly affect the breakthrough behaviour of impregnated carbon systems at high vapour concentration of CCl4 whereasbreak through time of impregnated carbon systems reduced by an increase of relative humidity at low CCl4 vapour concentration.

  2. Fragmentation of molecular ions in differential mobility spectrometry as a method for identification of chemical warfare agents.

    PubMed

    Maziejuk, M; Puton, J; Szyposzyńska, M; Witkiewicz, Z

    2015-11-01

    The subject of the work is the use of differential mobility spectrometry (DMS) for the detection of chemical warfare agents (CWA). Studies were performed for mustard gas, i.e., bis(2-chloroethyl)sulfide (HD), sarin, i.e., O-isopropyl methylphosphonofluoridate (GB) and methyl salicylate (MS) used as test compounds. Measurements were conducted with two ceramic DMS analyzers of different constructions allowing the generation of an electric field with an intensity of more than 120 Td. Detector signals were measured for positive and negative modes of operation in a temperature range from 0 to 80 °C. Fragmentations of ions containing analyte molecules were observed for all tested compounds. The effective temperatures of fragmentation estimated on the basis of dispersion plots were equal from about 148 °C for GB to 178 °C for MS. It was found that values of separation voltage (SV) and compensation voltage (CV) at which the fragmentation of sample ions is observed may be the parameters improving the certainty of detection for different analytes. The DMS analyzers enabling the observation of ion fragmentation can be successfully used for effective CWA detection. PMID:26452948

  3. Efficient heterogeneous and environmentally friendly degradation of nerve agents on a tungsten-based POM.

    PubMed

    Mizrahi, Dana M; Saphier, Sigal; Columbus, Ishay

    2010-07-15

    Common (chemical warfare agent) CWA decontaminants exhibit harsh and corrosive characteristics, and are harmful to the environment. In the course of our quest for active sorbents as efficient decontaminants, Keggin-type polyoxometalate (POM) (NH(4))(3)PW(12)O(40) was tested for oxidative degradation of CWAs. Although oxidation did not take place, sarin (GB) and VX were smoothly decontaminated to non-toxic products within 1 and 10 days, respectively. Degradation was carried out directly on the powder, eliminating the need for solvents. Mustard gas (HD), whose degradation is highly dependent on oxidation, was not decontaminated by this POM. Solid state MAS NMR ((31)P and (13)C) was utilized both for POM characterization and for decontamination studies monitoring. PMID:20363072

  4. Agent amplified communication

    SciTech Connect

    Kautz, H.; Selman, B.; Milewski, A.

    1996-12-31

    We propose an agent-based framework for assisting and simplifying person-to-person communication for information gathering tasks. As an example, we focus on locating experts for any specified topic. In our approach, the informal person-to-person networks that exist within an organization are used to {open_quotes}referral chain{close_quotes} requests for expertise. User-agents help automate this process. The agents generate referrals by analyzing records of e-mail communication patterns. Simulation results show that the higher responsiveness of an agent-based system can be effectively traded for the higher accuracy of a completely manual approach. Furthermore, preliminary experience with a group of users on a prototype system has shown that useful automatic referrals can be found in practice. Our experience with actual users has also shown that privacy concerns are central to the successful deployment of personal agents: an advanced agent-based system will therefore need to reason about issues involving trust and authority.

  5. Based on a multi-agent system for multi-scale simulation and application of household's LUCC: a case study for Mengcha village, Mizhi county, Shaanxi province.

    PubMed

    Chen, Hai; Liang, Xiaoying; Li, Rui

    2013-01-01

    Multi-Agent Systems (MAS) offer a conceptual approach to include multi-actor decision making into models of land use change. Through the simulation based on the MAS, this paper tries to show the application of MAS in the micro scale LUCC, and reveal the transformation mechanism of difference scale. This paper starts with a description of the context of MAS research. Then, it adopts the Nested Spatial Choice (NSC) method to construct the multi-scale LUCC decision-making model. And a case study for Mengcha village, Mizhi County, Shaanxi Province is reported. Finally, the potentials and drawbacks of the following approach is discussed and concluded. From our design and implementation of the MAS in multi-scale model, a number of observations and conclusions can be drawn on the implementation and future research directions. (1) The use of the LUCC decision-making and multi-scale transformation framework provides, according to us, a more realistic modeling of multi-scale decision making process. (2) By using continuous function, rather than discrete function, to construct the decision-making of the households is more realistic to reflect the effect. (3) In this paper, attempts have been made to give a quantitative analysis to research the household interaction. And it provides the premise and foundation for researching the communication and learning among the households. (4) The scale transformation architecture constructed in this paper helps to accumulate theory and experience for the interaction research between the micro land use decision-making and the macro land use landscape pattern. Our future research work will focus on: (1) how to rational use risk aversion principle, and put the rule on rotation between household parcels into model. (2) Exploring the methods aiming at researching the household decision-making over a long period, it allows us to find the bridge between the long-term LUCC data and the short-term household decision-making. (3) Researching the

  6. Sunscreening Agents

    PubMed Central

    Martis, Jacintha; Shobha, V; Sham Shinde, Rutuja; Bangera, Sudhakar; Krishnankutty, Binny; Bellary, Shantala; Varughese, Sunoj; Rao, Prabhakar; Naveen Kumar, B.R.

    2013-01-01

    The increasing incidence of skin cancers and photodamaging effects caused by ultraviolet radiation has increased the use of sunscreening agents, which have shown beneficial effects in reducing the symptoms and reoccurrence of these problems. Many sunscreen compounds are in use, but their safety and efficacy are still in question. Efficacy is measured through indices, such as sun protection factor, persistent pigment darkening protection factor, and COLIPA guidelines. The United States Food and Drug Administration and European Union have incorporated changes in their guidelines to help consumers select products based on their sun protection factor and protection against ultraviolet radiation, whereas the Indian regulatory agency has not yet issued any special guidance on sunscreening agents, as they are classified under cosmetics. In this article, the authors discuss the pharmacological actions of sunscreening agents as well as the available formulations, their benefits, possible health hazards, safety, challenges, and proper application technique. New technologies and scope for the development of sunscreening agents are also discussed as well as the role of the physician in patient education about the use of these agents. PMID:23320122

  7. Spatio-temporal Dynamics of Land-use and Land-cover Change: A Multi-agent Simulation Model and Its Application to an Upland Watershed in Central Vietnam

    NASA Astrophysics Data System (ADS)

    Le, Q.; Vlek, P. L.; Park, S.

    2005-12-01

    Land-use and land-cover change (LUCC) is an essential environmental process that should be monitored and prognosticated to provide a basis for better land management policy. However, LUCC modeling is a challenge due to the complex nature and unexpected behavior of both human drivers and natural constraints. This paper presents a multi-agent-based model to simulate spatio-temporal land-use changes and the interdependent socio-economic dynamics emerging from the complex socio-ecological interactions at micro levels resulting from land-use policy interventions. The model provides land-use scenarios under alternative policy to support decisions on land management for improved rural livelihoods while protecting the environment. In the multi-agent simulation model, the human community is represented by household agents (heterogeneous farming households) with their profiles and decision-making mechanisms about land use. The household profile defines the five asset dimensions of household livelihood (e.g., social, human, financial, natural and physical assets). The land-use decision-making program works by taking inputs from the household profile, perceived spatial environmental attributes, and introduced policies. The decision-making program is a logical procedure that combines a land-use choice model (multi-nominal logistic choices) and anthropological rules. The landscape environment is represented by landscape agents (congruent land patches of 30mx30m) with their state variables and ecological response mechanisms to environmental changes and human interventions. State variables of landscape agents correspond to spatial GIS-raster layers of biophysical, economic, and institutional variables. Ecological mechanisms of landscape agents are represented by internal sub-models of agricultural and forest productivity dynamics, which work in response to the current state, history, and spatial neighbourhood of the landscape agents. A multi-agent based protocol coordinates the

  8. Ex Vivo Perfusion-Simulation Measurements of Microbubbles as a Scattering Contrast Agent for Grating-Based X-Ray Dark-Field Imaging.

    PubMed

    Velroyen, Astrid; Bech, Martin; Tapfer, Arne; Yaroshenko, Andre; Müller, Mark; Paprottka, Philipp; Ingrisch, Michael; Cyran, Clemens C; Auweter, Sigrid D; Nikolaou, Konstantin; Reiser, Maximilian F; Pfeiffer, Franz

    2015-01-01

    The investigation of dedicated contrast agents for x-ray dark-field imaging, which exploits small-angle scattering at microstructures for contrast generation, is of strong interest in analogy to the common clinical use of high-atomic number contrast media in conventional attenuation-based imaging, since dark-field imaging has proven to provide complementary information. Therefore, agents consisting of gas bubbles, as used in ultrasound imaging for example, are of particular interest. In this work, we investigate an experimental contrast agent based on microbubbles consisting of a polyvinyl-alcohol shell with an iron oxide coating, which was originally developed for multimodal imaging and drug delivery. Its performance as a possible contrast medium for small-animal angiography was examined using a mouse carcass to realistically consider attenuating and scattering background signal. Subtraction images of dark field, phase contrast and attenuation were acquired for a concentration series of 100%, 10% and 1.3% to mimic different stages of dilution in the contrast agent in the blood vessel system. The images were compared to the gold-standard iodine-based contrast agent Solutrast, showing a good contrast improvement by microbubbles in dark-field imaging. This study proves the feasibility of microbubble-based dark-field contrast-enhancement in presence of scattering and attenuating mouse body structures like bone and fur. Therefore, it suggests a strong potential of the use of polymer-based microbubbles for small-animal dark-field angiography. PMID:26134130

  9. Ex Vivo Perfusion-Simulation Measurements of Microbubbles as a Scattering Contrast Agent for Grating-Based X-Ray Dark-Field Imaging

    PubMed Central

    Velroyen, Astrid; Bech, Martin; Tapfer, Arne; Yaroshenko, Andre; Müller, Mark; Paprottka, Philipp; Ingrisch, Michael; Cyran, Clemens C.; Auweter, Sigrid D.; Nikolaou, Konstantin; Reiser, Maximilian F.; Pfeiffer, Franz

    2015-01-01

    The investigation of dedicated contrast agents for x-ray dark-field imaging, which exploits small-angle scattering at microstructures for contrast generation, is of strong interest in analogy to the common clinical use of high-atomic number contrast media in conventional attenuation-based imaging, since dark-field imaging has proven to provide complementary information. Therefore, agents consisting of gas bubbles, as used in ultrasound imaging for example, are of particular interest. In this work, we investigate an experimental contrast agent based on microbubbles consisting of a polyvinyl-alcohol shell with an iron oxide coating, which was originally developed for multimodal imaging and drug delivery. Its performance as a possible contrast medium for small-animal angiography was examined using a mouse carcass to realistically consider attenuating and scattering background signal. Subtraction images of dark field, phase contrast and attenuation were acquired for a concentration series of 100%, 10% and 1.3% to mimic different stages of dilution in the contrast agent in the blood vessel system. The images were compared to the gold-standard iodine-based contrast agent Solutrast, showing a good contrast improvement by microbubbles in dark-field imaging. This study proves the feasibility of microbubble-based dark-field contrast-enhancement in presence of scattering and attenuating mouse body structures like bone and fur. Therefore, it suggests a strong potential of the use of polymer-based microbubbles for small-animal dark-field angiography. PMID:26134130

  10. Antidiabetic Agents.

    ERIC Educational Resources Information Center

    Plummer, Nancy; Michael, Nancy, Ed.

    This module on antidiabetic agents is intended for use in inservice or continuing education programs for persons who administer medications in long-term care facilities. Instructor information, including teaching suggestions, and a listing of recommended audiovisual materials and their sources appear first. The module goal and objectives are then…

  11. Analysis of Nerve Agent Metabolites from Hair for Long-Term Verification of Nerve Agent Exposure.

    PubMed

    Appel, Amanda S; McDonough, John H; McMonagle, Joseph D; Logue, Brian A

    2016-06-21

    Several methods for the bioanalysis of nerve agents or their metabolites have been developed for the verification of nerve agent exposure. However, parent nerve agents and known metabolites are generally rapidly excreted from biological matrixes typically used for analysis (i.e., blood, urine, and tissues), limiting the amount of time after an exposure that verification is feasible. In this study, hair was evaluated as a long-term repository of nerve agent hydrolysis products. Pinacolyl methylphosphonic acid (PMPA; hydrolysis product of soman) and isopropyl methylphosphonic acid (IMPA; hydrolysis product of sarin) were extracted from hair samples with N,N-dimethylformamide and subsequently analyzed by liquid chromatography-tandem mass spectrometry. Limits of detection for PMPA and IMPA were 0.15 μg/kg and 7.5 μg/kg and linear ranges were 0.3-150 μg/kg and 7.5-750 μg/kg, respectively. To evaluate the applicability of the method to verify nerve agent exposure well after the exposure event, rats were exposed to soman, hair was collected after approximately 30 days, and stored for up to 3.5 years prior to initial analysis. PMPA was positively identified in 100% of the soman-exposed rats (N = 8) and was not detected in any of the saline treated animals (N = 6). The hair was reanalyzed 5.5 years after exposure and PMPA was detected in 6 of the 7 (one of the soman-exposed hair samples was completely consumed in the analysis at 3.5 years) rat hair samples (with no PMPA detected in the saline exposed animals). Although analysis of CWA metabolites from hair via this technique is not appropriate as a universal method to determine exposure (i.e., it takes time for the hair to grow above the surface of the skin and typical analysis times are >24 h), it complements existing methods and could become the preferred method for verification of exposure if 10 or more days have elapsed after a suspected exposure. PMID:27161086

  12. Test operations procedure (TOP) 8-2-501, permeation and penetration of air-permeable, semipermeable, and impermeable materials with chemical agents or simulants (swatch testing). Final report

    SciTech Connect

    1997-03-03

    This test operations procedure (TOP) provides the current standard for planning and conducting tests to measure the permeation or penetration of swatches of materials by chemical agents such as distilled mustard (HD), or the nerve agents sarin (GB), or V-agent (VX). The swatches may be single or multi-layered, inert, sorptive or reactive. Swatches may be taken from candidate or standardized fabrics, in which case application of this TOP can provide relative ranking or screening information about the ability of the standardized and/or candidate materials to resist permeation or penetration by chemical agents. Swatches may also be taken from garments that are new, have been stored, or have been worn for various times under different conditions. Testing these material swatches using the procedures in the TOP can provide data to evaluate the effects of the different condition of wear. This TOP is not adequate for the assessment of the ability of an end item clothing made from any tested material to protect the wearer. The data obtained by these procedures cannot be correlated to field conditions. One or more of the test procedures given may be required in a detailed test plan (DTP).

  13. Learning-by-Teaching: Designing Teachable Agents with Intrinsic Motivation

    ERIC Educational Resources Information Center

    Zhao, Guopeng; Ailiya; Shen, Zhiqi

    2012-01-01

    Teachable agent is a type of pedagogical agent which instantiates Learning-by-Teaching theory through simulating a "naive" learner in order to motivate students to teach it. This paper discusses the limitation of existing teachable agents and incorporates intrinsic motivation to the agent model to enable teachable agents with initiative behaviors…

  14. Agent-based modeling of complex infrastructures

    SciTech Connect

    North, M. J.

    2001-06-01

    Complex Adaptive Systems (CAS) can be applied to investigate complex infrastructures and infrastructure interdependencies. The CAS model agents within the Spot Market Agent Research Tool (SMART) and Flexible Agent Simulation Toolkit (FAST) allow investigation of the electric power infrastructure, the natural gas infrastructure and their interdependencies.

  15. Antiparasitic agents.

    PubMed

    Rosenblatt, J E

    1999-11-01

    Several important developments have occurred in recent years in the chemotherapy for and prophylaxis of parasitic infections. Although mefloquine is clearly the most effective agent for prevention of chloroquine-resistant falciparum malaria, its use has been compromised by side effects, both real and imagined. Well-designed studies have shown that side effects occur no more frequently with low-dose mefloquine than with chloroquine. Use of mefloquine in pregnant women has not been associated with birth defects, but the incidence of stillbirths may be increased. Malarone is a new agent that combines atovaquone and proguanil, and it may be as effective as mefloquine; however, it is not yet available in the United States. Several newer agents have appeared in response to the development of multidrug resistant Plasmodium falciparum, especially in Southeast Asia. Halofantrine is available for the treatment of mild to moderate malaria due to P. falciparum and for P. vivax infections. Because of severe toxic effects, use of halofantrine should be restricted to only those unusual and rare situations in which other agents cannot be used. Artemisinin (an extract of the Chinese herbal remedy qinghaosu) and two derivatives, artesunate and artemether, are active against multidrug resistant P. falciparum and are widely used in Asia in oral, parenteral, and rectal forms. The antibacterial azithromycin in combination with atovaquone or quinine has now been reported to treat babesiosis effectively in experimental animals and in a few patients. Azithromycin in combination with paromomycin has also shown promise in the treatment of cryptosporidiosis (and toxoplasmosis when combined with pyrimethamine) in patients with the acquired immunodeficiency syndrome (AIDS). Albendazole is currently the only systemic agent available for treatment of microsporidiosis, an infection primarily of patients with AIDS. In addition, albendazole and ivermectin have emerged as effective broad

  16. Estimation of the age-specific per-contact probability of Ebola virus transmission in Liberia using agent-based simulations

    NASA Astrophysics Data System (ADS)

    Siettos, Constantinos I.; Anastassopoulou, Cleo; Russo, Lucia; Grigoras, Christos; Mylonakis, Eleftherios

    2016-06-01

    Based on multiscale agent-based computations we estimated the per-contact probability of transmission by age of the Ebola virus disease (EVD) that swept through Liberia from May 2014 to March 2015. For the approximation of the epidemic dynamics we have developed a detailed agent-based model with small-world interactions between individuals categorized by age. For the estimation of the structure of the evolving contact network as well as the per-contact transmission probabilities by age group we exploited the so called Equation-Free framework. Model parameters were fitted to official case counts reported by the World Health Organization (WHO) as well as to recently published data of key epidemiological variables, such as the mean time to death, recovery and the case fatality rate.

  17. Pathogenetic validation of the use of biological protective agents and early treatment in cases of radiation injury simulating radiation effects under space flight conditions

    NASA Technical Reports Server (NTRS)

    Rogozkin, V. D.; Varteres, V.; Sabo, L.; Groza, N.; Nikolov, I.

    1974-01-01

    In considering a radiation safety system for space flights, the various measures to protect man against radiation include drug prophylaxis. At the present time a great deal of experimental material has been accumulated on the prevention and treatment of radiation injuries. Antiradiation effectiveness has been established for sulfur- and nitrogen-containing substances, auxins, cyanides, polynucleotides, mucopolysaccharides, lipopolysaccharides, aminosaccharides, synthetic polymers, vitamins, hormones, amino acids and other compounds which can be divided into two basic groups - biological and chemical protective agents.

  18. Kromoscopy for detection of chemical warfare agents

    NASA Astrophysics Data System (ADS)

    Ewing, Kenneth J.; Sanghera, Jas; Aggarwal, Ishwar D.; Block, Myron J.

    2004-12-01

    The ability of a Kromoscope to discriminate between chemical warfare agent simulants and toxic industrial chemicals is evaluated. The Kromoscope response to the simulants DMMP and DIMP is compared to a pesticide (diazanon) and cyclopentanol. The response of a mid-infrared Kromoscope to the nerve agents VX and GB and the stimulant DF are calculated.

  19. A wrench in the works of human acetylcholinesterase: Soman induced conformational changes revealed by molecular dynamics simulations

    SciTech Connect

    Bennion, Brian J.; Essiz, Sebnem G.; Lau, Edmond Y.; Fattebert, Jean -Luc; Emigh, Aiyana; Lightstone, Felice C.; Salsbury , Jr, Freddie

    2015-04-13

    Irreversible inactivation of human acetylcholinesterase (hAChE) by organophosphorous pesticides (OPs) and chemical weapon agents (CWA) has severe morbidity and mortality consequences. We present data from quantum mechanics/molecular mechanics (QM/MM) and 80 classical molecular dynamics (MD) simulations of the apo and soman-adducted forms of hAChE to investigate the effects on the dynamics and protein structure when the catalytic Serine 203 is phosphonylated. We find that the soman phosphonylation of the active site Ser203 follows a water assisted addition-elimination mechanism with the elimination of the fluoride ion being the highest energy barrier at 6.5 kcal/mole. We observe soman-dependent changes in backbone and sidechain motions compared to the apo form of the protein. These alterations restrict the soman-adducted hAChE to a structural state that is primed for the soman adduct to be cleaved and removed from the active site. The altered motions and resulting structures provide alternative pathways into and out of the hAChE active site. In the soman-adducted protein both side and back door pathways are viable for soman adduct access. Correlation analysis of the apo and soman adducted MD trajectories shows that the correlation of gorge entrance and back door motion is disrupted when hAChE is adducted. This supports the hypothesis that substrate and product can use two different pathways as entry and exit sites in the apo form of the protein. These alternative pathways have important implications for the rational design of medical countermeasures.

  20. A wrench in the works of human acetylcholinesterase: Soman induced conformational changes revealed by molecular dynamics simulations

    DOE PAGESBeta

    Bennion, Brian J.; Essiz, Sebnem G.; Lau, Edmond Y.; Fattebert, Jean -Luc; Emigh, Aiyana; Lightstone, Felice C.; Salsbury , Jr, Freddie

    2015-04-13

    Irreversible inactivation of human acetylcholinesterase (hAChE) by organophosphorous pesticides (OPs) and chemical weapon agents (CWA) has severe morbidity and mortality consequences. We present data from quantum mechanics/molecular mechanics (QM/MM) and 80 classical molecular dynamics (MD) simulations of the apo and soman-adducted forms of hAChE to investigate the effects on the dynamics and protein structure when the catalytic Serine 203 is phosphonylated. We find that the soman phosphonylation of the active site Ser203 follows a water assisted addition-elimination mechanism with the elimination of the fluoride ion being the highest energy barrier at 6.5 kcal/mole. We observe soman-dependent changes in backbone andmore » sidechain motions compared to the apo form of the protein. These alterations restrict the soman-adducted hAChE to a structural state that is primed for the soman adduct to be cleaved and removed from the active site. The altered motions and resulting structures provide alternative pathways into and out of the hAChE active site. In the soman-adducted protein both side and back door pathways are viable for soman adduct access. Correlation analysis of the apo and soman adducted MD trajectories shows that the correlation of gorge entrance and back door motion is disrupted when hAChE is adducted. This supports the hypothesis that substrate and product can use two different pathways as entry and exit sites in the apo form of the protein. These alternative pathways have important implications for the rational design of medical countermeasures.« less

  1. A Wrench in the Works of Human Acetylcholinesterase: Soman Induced Conformational Changes Revealed by Molecular Dynamics Simulations

    PubMed Central

    Fattebert, Jean-Luc; Emigh, Aiyana

    2015-01-01

    Irreversible inactivation of human acetylcholinesterase (hAChE) by organophosphorous pesticides (OPs) and chemical weapon agents (CWA) has severe morbidity and mortality consequences. We present data from quantum mechanics/molecular mechanics (QM/MM) and 80 classical molecular dynamics (MD) simulations of the apo and soman-adducted forms of hAChE to investigate the effects on the dynamics and protein structure when the catalytic Serine 203 is phosphonylated. We find that the soman phosphonylation of the active site Ser203 follows a water assisted addition-elimination mechanism with the elimination of the fluoride ion being the highest energy barrier at 6.5 kcal/mole. We observe soman-dependent changes in backbone and sidechain motions compared to the apo form of the protein. These alterations restrict the soman-adducted hAChE to a structural state that is primed for the soman adduct to be cleaved and removed from the active site. The altered motions and resulting structures provide alternative pathways into and out of the hAChE active site. In the soman-adducted protein both side and back door pathways are viable for soman adduct access. Correlation analysis of the apo and soman adducted MD trajectories shows that the correlation of gorge entrance and back door motion is disrupted when hAChE is adducted. This supports the hypothesis that substrate and product can use two different pathways as entry and exit sites in the apo form of the protein. These alternative pathways have important implications for the rational design of medical countermeasures. PMID:25874456

  2. Antifungal agents.

    PubMed

    Ryder, N S

    1999-12-01

    At this year's ICAAC Meeting, new data on approximately 20 different antifungal agents were presented, while no new agents were disclosed. Drugs in late development include the triazoles, voriconazole (Pfizer Ltd) and Sch-56592 (Schering-Plough Corp), and the echinocandins, caspofungin (Merck & Co Inc) and FK-463 (Fujisawa Pharmaceutical Co Ltd). In contrast to previous years, presentations on these and earlier developmental compounds were relatively modest in scope, with few significant new data. Little new information appeared on the most recent novel class of agents, the sordarins (Glaxo Wellcome plc). Early clinical results were presented for FK-463, showing acceptable tolerability and dose-dependent efficacy in AIDS-associated esophageal candidiasis. A new liposomal formulation of nystatin (Nyotran; Aronex Pharmaceuticals Inc) was shown to be equivalent to conventional amphotericin B in empiric therapy of presumed fungal infection in neutropenic patients, but with reduced toxicity. Intravenous itraconazole (Janssen Pharmaceutica NV) was an effective prophylactic therapy in invasive pulmonary aspergillosis, while oral itraconazole was discussed as a treatment for fungal infection in heart and liver transplant patients. The allylamine compound, terbinafine (Novartis AG), showed good clinical efficacy against fungal mycetoma, a serious tropical infection. A major highlight was the first presentation of inhibitors of fungal efflux pumps as a strategy for overcoming resistance. MC-510027 (milbemycin alpha-9; Microcide Pharmaceuticals Inc) and its derivatives, potentiated the antifungal activity of triazoles and terbinafine in a number of Candida spp. Another pump inhibitor, MC-005172 (Microcide Pharmaceuticals Inc) showed in vivo potentiation of fluconazole in a mouse kidney infection model. Microcide Pharmaceuticals Inc also presented inhibitors of bacterial efflux pumps. PMID:16113946

  3. KGB agents

    NASA Astrophysics Data System (ADS)

    Gaina, Alex

    A short story is reported in which the activity of Communist Party of the USSR and secret KGB agents, which were payed by the State, in view of controlling of the conscience of population. The story reffers to the Physics Department of the Moscow University, Planing Institute of the Gosplan of Moldavian S.S.R. and Chishinau Technical University (actually: Technical University of Moldova), where the author has worked during Soviet times. Almost every 6-th citizen in the USSR was engaged in this activity, while actually the former communists rule in the Republic of Moldova.

  4. What makes virtual agents believable?

    NASA Astrophysics Data System (ADS)

    Bogdanovych, Anton; Trescak, Tomas; Simoff, Simeon

    2016-01-01

    In this paper we investigate the concept of believability and make an attempt to isolate individual characteristics (features) that contribute to making virtual characters believable. As the result of this investigation we have produced a formalisation of believability and based on this formalisation built a computational framework focused on simulation of believable virtual agents that possess the identified features. In order to test whether the identified features are, in fact, responsible for agents being perceived as more believable, we have conducted a user study. In this study we tested user reactions towards the virtual characters that were created for a simulation of aboriginal inhabitants of a particular area of Sydney, Australia in 1770 A.D. The participants of our user study were exposed to short simulated scenes, in which virtual agents performed some behaviour in two different ways (while possessing a certain aspect of believability vs. not possessing it). The results of the study indicate that virtual agents that appear resource bounded, are aware of their environment, own interaction capabilities and their state in the world, agents that can adapt to changes in the environment and exist in correct social context are those that are being perceived as more believable. Further in the paper we discuss these and other believability features and provide a quantitative analysis of the level of contribution for each such feature to the overall perceived believability of a virtual agent.

  5. Chemical warfare agent detection in complex environments with comprehensive two-dimensional gas chromatography

    NASA Astrophysics Data System (ADS)

    Reichenbach, Stephen E.; Ni, Mingtian; Kottapalli, Visweswara; Visvanathan, Arvind; Ledford, Edward B., Jr.; Oostdijk, John; Trap, Henk C.

    2003-08-01

    Comprehensive two-dimensional gas chromatography (GCxGC) is an emerging technology for chemical separation that provides an order-of-magnitude increase in separation capacity over traditional gas chromatography. GCxGC separates chemical species with two capillary columns interfaced by two-stage thermal desorption. Because GCxGC is comprehensive and has high separation capacity, it can perform multiple traditional analytical methods with a single analysis. GCxGC has great potential for a wide variety of environmental sensing applications, including detection of chemical warfare agents (CWA) and other harmful chemicals. This paper demonstrates separation of nerve agents sarin and soman from a matrix of gasoline and diesel fuel. Using a combination of an initial column separating on the basis of boiling point and a second column separating on the basis of polarity, GCxGC clearly separates the nerve agents from the thousands of other chemicals in the sample. The GCxGC data is visualized, processed, and analyzed as a two-dimensional digital image using a software system for GCxGC image processing developed at the University of Nebraska - Lincoln.

  6. Health care agents

    MedlinePlus

    Durable power of attorney for health care; Health care proxy; End-of-life - health care agent; Life support treatment - ... Respirator - health care agent; Ventilator - health care agent; Power of attorney - health care agent; POA - health care ...

  7. Agent Building Software

    NASA Technical Reports Server (NTRS)

    2000-01-01

    AgentBuilder is a software component developed under an SBIR contract between Reticular Systems, Inc., and Goddard Space Flight Center. AgentBuilder allows software developers without experience in intelligent agent technologies to easily build software applications using intelligent agents. Agents are components of software that will perform tasks automatically, with no intervention or command from a user. AgentBuilder reduces the time and cost of developing agent systems and provides a simple mechanism for implementing high-performance agent systems.

  8. Who's your neighbor? neighbor identification for agent-based modeling.

    SciTech Connect

    Macal, C. M.; Howe, T. R.; Decision and Information Sciences; Univ. of Chicago

    2006-01-01

    Agent-based modeling and simulation, based on the cellular automata paradigm, is an approach to modeling complex systems comprised of interacting autonomous agents. Open questions in agent-based simulation focus on scale-up issues encountered in simulating large numbers of agents. Specifically, how many agents can be included in a workable agent-based simulation? One of the basic tenets of agent-based modeling and simulation is that agents only interact and exchange locally available information with other agents located in their immediate proximity or neighborhood of the space in which the agents are situated. Generally, an agent's set of neighbors changes rapidly as a simulation proceeds through time and as the agents move through space. Depending on the topology defined for agent interactions, proximity may be defined by spatial distance for continuous space, adjacency for grid cells (as in cellular automata), or by connectivity in social networks. Identifying an agent's neighbors is a particularly time-consuming computational task and can dominate the computational effort in a simulation. Two challenges in agent simulation are (1) efficiently representing an agent's neighborhood and the neighbors in it and (2) efficiently identifying an agent's neighbors at any time in the simulation. These problems are addressed differently for different agent interaction topologies. While efficient approaches have been identified for agent neighborhood representation and neighbor identification for agents on a lattice with general neighborhood configurations, other techniques must be used when agents are able to move freely in space. Techniques for the analysis and representation of spatial data are applicable to the agent neighbor identification problem. This paper extends agent neighborhood simulation techniques from the lattice topology to continuous space, specifically R2. Algorithms based on hierarchical (quad trees) or non-hierarchical data structures (grid cells) are

  9. GIS and agent based spatial-temporal simulation modeling for assessing tourism social carrying capacity: a study on Mount Emei scenic area, China

    NASA Astrophysics Data System (ADS)

    Zhang, Renjun

    2007-06-01

    Each scenic area can sustain a specific level of acceptance of tourist development and use, beyond which further development can result in socio-cultural deterioration or a decline in the quality of the experience gained by visitors. This specific level is called carrying capacity. Social carrying capacity can be defined as the maximum level of use (in terms of numbers and activities) that can be absorbed by an area without an unacceptable decline in the quality of experience of visitors and without an unacceptable adverse impact on the society of the area. It is difficult to assess the carrying capacity, because the carrying capacity is determined by not only the number of visitors, but also the time, the type of the recreation, the characters of each individual and the physical environment. The objective of this study is to build a spatial-temporal simulation model to simulate the spatial-temporal distribution of tourists. This model is a tourist spatial behaviors simulator (TSBS). Based on TSBS, the changes of each visitor's travel patterns such as location, cost, and other states data are recoded in a state table. By analyzing this table, the intensity of the tourist use in any area can be calculated; the changes of the quality of tourism experience can be quantized and analyzed. So based on this micro simulation method the social carrying capacity can be assessed more accurately, can be monitored proactively and managed adaptively. In this paper, the carrying capacity of Mount Emei scenic area is analyzed as followed: The author selected the intensity of the crowd as the monitoring Indicators. it is regarded that longer waiting time means more crowded. TSBS was used to simulate the spatial-temporal distribution of tourists. the average of waiting time all the visitors is calculated. And then the author assessed the social carrying capacity of Mount Emei scenic area, found the key factors have impacted on social carrying capacity. The results show that the TSBS

  10. Development of an Agent-Based Model (ABM) to Simulate the Immune System and Integration of a Regression Method to Estimate the Key ABM Parameters by Fitting the Experimental Data

    PubMed Central

    Tong, Xuming; Chen, Jinghang; Miao, Hongyu; Li, Tingting; Zhang, Le

    2015-01-01

    Agent-based models (ABM) and differential equations (DE) are two commonly used methods for immune system simulation. However, it is difficult for ABM to estimate key parameters of the model by incorporating experimental data, whereas the differential equation model is incapable of describing the complicated immune system in detail. To overcome these problems, we developed an integrated ABM regression model (IABMR). It can combine the advantages of ABM and DE by employing ABM to mimic the multi-scale immune system with various phenotypes and types of cells as well as using the input and output of ABM to build up the Loess regression for key parameter estimation. Next, we employed the greedy algorithm to estimate the key parameters of the ABM with respect to the same experimental data set and used ABM to describe a 3D immune system similar to previous studies that employed the DE model. These results indicate that IABMR not only has the potential to simulate the immune system at various scales, phenotypes and cell types, but can also accurately infer the key parameters like DE model. Therefore, this study innovatively developed a complex system development mechanism that could simulate the complicated immune system in detail like ABM and validate the reliability and efficiency of model like DE by fitting the experimental data. PMID:26535589

  11. Development of an Agent-Based Model (ABM) to Simulate the Immune System and Integration of a Regression Method to Estimate the Key ABM Parameters by Fitting the Experimental Data.

    PubMed

    Tong, Xuming; Chen, Jinghang; Miao, Hongyu; Li, Tingting; Zhang, Le

    2015-01-01

    Agent-based models (ABM) and differential equations (DE) are two commonly used methods for immune system simulation. However, it is difficult for ABM to estimate key parameters of the model by incorporating experimental data, whereas the differential equation model is incapable of describing the complicated immune system in detail. To overcome these problems, we developed an integrated ABM regression model (IABMR). It can combine the advantages of ABM and DE by employing ABM to mimic the multi-scale immune system with various phenotypes and types of cells as well as using the input and output of ABM to build up the Loess regression for key parameter estimation. Next, we employed the greedy algorithm to estimate the key parameters of the ABM with respect to the same experimental data set and used ABM to describe a 3D immune system similar to previous studies that employed the DE model. These results indicate that IABMR not only has the potential to simulate the immune system at various scales, phenotypes and cell types, but can also accurately infer the key parameters like DE model. Therefore, this study innovatively developed a complex system development mechanism that could simulate the complicated immune system in detail like ABM and validate the reliability and efficiency of model like DE by fitting the experimental data. PMID:26535589

  12. Safe motion planning for mobile agents: A model of reactive planning for multiple mobile agents

    SciTech Connect

    Fujimura, Kikuo.

    1990-01-01

    The problem of motion planning for multiple mobile agents is studied. Each planning agent independently plans its own action based on its map which contains a limited information about the environment. In an environment where more than one mobile agent interacts, the motions of the robots are uncertain and dynamic. A model for reactive agents is described and simulation results are presented to show their behavior patterns. 18 refs., 2 figs.

  13. Spectrally-resolved fluorescence cross sections of aerosolized biological live agents and simulants using five excitation wavelengths in a BSL-3 laboratory.

    PubMed

    Pan, Yong-Le; Hill, Steven C; Santarpia, Joshua L; Brinkley, Kelly; Sickler, Todd; Coleman, Mark; Williamson, Chatt; Gurton, Kris; Felton, Melvin; Pinnick, Ronald G; Baker, Neal; Eshbaugh, Jonathan; Hahn, Jerry; Smith, Emily; Alvarez, Ben; Prugh, Amber; Gardner, Warren

    2014-04-01

    A system for measuring spectrally-resolved fluorescence cross sections of single bioaerosol particles has been developed and employed in a biological safety level 3 (BSL-3) facility at Edgewood Chemical and Biological Center (ECBC). It is used to aerosolize the slurry or solution of live agents and surrogates into dried micron-size particles, and to measure the fluorescence spectra and sizes of the particles one at a time. Spectrally-resolved fluorescence cross sections were measured for (1) bacterial spores: Bacillus anthracis Ames (BaA), B. atrophaeus var. globigii (BG) (formerly known as Bacillus globigii), B. thuringiensis israelensis (Bti), B. thuringiensis kurstaki (Btk), B. anthracis Sterne (BaS); (2) vegetative bacteria: Escherichia coli (E. coli), Pantoea agglomerans (Eh) (formerly known as Erwinia herbicola), Yersinia rohdei (Yr), Yersinia pestis CO92 (Yp); and (3) virus preparations: Venezuelan equine encephalitis TC83 (VEE) and the bacteriophage MS2. The excitation wavelengths were 266 nm, 273 nm, 280 nm, 365 nm and 405 nm. PMID:24718194

  14. Launch Commit Criteria Monitoring Agent

    NASA Technical Reports Server (NTRS)

    Semmel, Glenn S.; Davis, Steven R.; Leucht, Kurt W.; Rowe, Dan A.; Kelly, Andrew O.; Boeloeni, Ladislau

    2005-01-01

    The Spaceport Processing Systems Branch at NASA Kennedy Space Center has developed and deployed a software agent to monitor the Space Shuttle's ground processing telemetry stream. The application, the Launch Commit Criteria Monitoring Agent, increases situational awareness for system and hardware engineers during Shuttle launch countdown. The agent provides autonomous monitoring of the telemetry stream, automatically alerts system engineers when predefined criteria have been met, identifies limit warnings and violations of launch commit criteria, aids Shuttle engineers through troubleshooting procedures, and provides additional insight to verify appropriate troubleshooting of problems by contractors. The agent has successfully detected launch commit criteria warnings and violations on a simulated playback data stream. Efficiency and safety are improved through increased automation.

  15. Monoterpenes as nitrofurantoin resistance modulating agents: minimal structural requirements, molecular dynamics simulations, and the effect of piperitone on the emergence of nitrofurantoin resistance in Enterobacteriaceae.

    PubMed

    Shahverdi, Ahmad R; Mirzaie, Sako; Rafii, Fatemeh; Kakavand, Marjan; Foroumadi, Alireza

    2015-08-01

    The effects of different monoterpenes and 2-cyclohexen-1-one on the antibacterial activity of nitrofurantoin against resistant Enterobacter cloacae, were compared and the minimal structural component of monoterpene required for the highest level of resistance-modulating activity was determined. Subinhibitory concentrations of all compounds tested enhanced the antibacterial activity of nitrofurantoin against E. cloacae to different extents. The highest synergistic effect was observed for the monoterpenes, like piperitone, which contained a conjugated ketone and C=C bond in their carbon ring structure. Piperitone also suppressed the emergence of nitrofurantoin-resistant strains of Enterobacteriaceae that were mutagenized by ethyl methanesulfonate. The modes of interaction of carvone, piperitone, and an enzyme inhibitor, benzoate, with nitroreductase were investigated by molecular docking and molecular dynamic (MD) simulation for 20 ns. MD simulation supported greater stability of the benzoate and monoterpene-nitroreductase (NR) complexes than of free NR. The results of this investigation are promising for the synthesis of more effective lead compounds to enhance the antibacterial activity of nitro drugs against resistant Enterobacter strains. PMID:26174760

  16. Proceedings of the Agent 2002 Conference on Social Agents : Ecology, Exchange, and Evolution

    SciTech Connect

    Macal, C., ed.; Sallach, D., ed.

    2003-04-10

    Welcome to the ''Proceedings'' of the third in a series of agent simulation conferences cosponsored by Argonne National Laboratory and The University of Chicago. The theme of this year's conference, ''Social Agents: Ecology, Exchange and Evolution'', was selected to foster the exchange of ideas on some of the most important social processes addressed by agent simulation models, namely: (1) The translation of ecology and ecological constraints into social dynamics; (2) The role of exchange processes, including the peer dependencies they create; and (3) The dynamics by which, and the attractor states toward which, social processes evolve. As stated in the ''Call for Papers'', throughout the social sciences, the simulation of social agents has emerged as an innovative and powerful research methodology. The promise of this approach, however, is accompanied by many challenges. First, modeling complexity in agents, environments, and interactions is non-trivial, and these representations must be explored and assessed systematically. Second, strategies used to represent complexities are differentially applicable to any particular problem space. Finally, to achieve sufficient generality, the design and experimentation inherent in agent simulation must be coupled with social and behavioral theory. Agent 2002 provides a forum for reviewing the current state of agent simulation scholarship, including research designed to address such outstanding issues. This year's conference introduces an extensive range of domains, models, and issues--from pre-literacy to future projections, from ecology to oligopolistic markets, and from design to validation. Four invited speakers highlighted major themes emerging from social agent simulation.

  17. Preparing Change Agents for Change Agent Roles.

    ERIC Educational Resources Information Center

    Sedlacek, James R.

    Seventy-seven Spanish- and Portuguese-speaking agricultural change agents from developing Central and South American countries responded to a questionnaire which sought perceptions of the roles in which the change agents felt they were involved and the roles for which they felt they were being trained. The agents were participating in training…

  18. A multi-agent architecture for geosimulation of moving agents

    NASA Astrophysics Data System (ADS)

    Vahidnia, Mohammad H.; Alesheikh, Ali A.; Alavipanah, Seyed Kazem

    2015-10-01

    In this paper, a novel architecture is proposed in which an axiomatic derivation system in the form of first-order logic facilitates declarative explanation and spatial reasoning. Simulation of environmental perception and interaction between autonomous agents is designed with a geographic belief-desire-intention and a request-inform-query model. The architecture has a complementary quantitative component that supports collaborative planning based on the concept of equilibrium and game theory. This new architecture presents a departure from current best practices geographic agent-based modelling. Implementation tasks are discussed in some detail, as well as scenarios for fleet management and disaster management.

  19. Economic Path Scheduling for Mobile Agent System on Computer Network

    NASA Astrophysics Data System (ADS)

    Olajubu, E. A.

    Mobile agent technology has a lot of gains to offer network-centric applications. The technology promises to be very suitable for narrow-bandwidth networks by reducing network latency and allowing transparent per-to-per computing. Multi-agent technology had been proposed for many network-centric applications with little or no path scheduling algorithms. This paper describes the need for path scheduling algorithms for agents in multi-agent systems. Traveling salesman problem (TSP) scheme is used to model ordered agents and the unordered agents schedule their path based on random distribution. The two types of agents were modeled and simulated based on bandwidth usage and response time as performance metrics. Our simulation results shows that ordered agents have superior performance against unordered agents. The ordered agents exhibit lower bandwidth usage and higher response time.

  20. Identification of chemical warfare agents using a portable microchip-based detection device

    NASA Astrophysics Data System (ADS)

    Petkovic-Duran, K.; Swallow, A.; Sexton, B. A.; Glenn, F.; Zhu, Y.

    2011-12-01

    Analysis of chemical warfare agents (CWAs) and their degradation products is an important verification component in support of the Chemical Weapons Convention and urgently demanding rapid and reliable analytical methods. A portable microchip electrophoresis (ME) device with contactless conductivity (CCD) detection was developed for the in situ identification of CWA and their degradation products. A 10mM MES/His, 0.4mM CTAB - based separation electrolyte accomplished the analysis of Sarin (GB), Tabun( GA) and Soman (GD) in less than 1 min, which is the fastest screening of nerve agents achieved with portable ME and CCD based detection methods to date. Reproducibility of detection was successfully demonstrated on simultaneous detection of GB (200ppm) and GA (278ppm). Reasonable agreement for the four consecutive runs was achieved with the mean peak time for Sarin of 29.15s, and the standard error of 0.58s or 2%. GD and GA were simultaneously detected with their degradation products methylphosphonic acid (MPA), pinacolyl methylphosphonic acid (PMPA) and O-Ethyl Phosphorocyanidate (GAHP and GAHP1) respectively. The detection limit for Sarin was around 35ppb. To the best of our knowledge this is the best result achieved in microchip electrophoresis and contactless conductivity based detection to date.

  1. Water security: continuous monitoring of water distribution systems for chemical agents by SERS

    NASA Astrophysics Data System (ADS)

    Inscore, Frank; Shende, Chetan; Sengupta, Atanu; Farquharson, Stuart

    2007-04-01

    Ensuring safe water supplies requires continuous monitoring for potential poisons and portable analyzers to map distribution in the event of an attack. In the case of chemical warfare agents (CWAs) analyzers are needed that have sufficient sensitivity (part-per-billion), selectivity (differentiate the CWA from its hydrolysis products), and speed (less than 10 minutes) to be of value. We have been investigating the ability of surface-enhanced Raman spectroscopy (SERS) to meet these requirements by detecting CWAs and their hydrolysis products in water. The expected success of SERS is based on reported detection of single molecules, the one-to-one relationship between a chemical and its Raman spectrum, and the minimal sample preparation requirements. Recently, we have developed a simple sampling device designed to optimize the interaction of the target molecules with the SERS-active material with the goal of increasing sensitivity and decreasing sampling times. This sampling device employs a syringe to draw the water sample containing the analyte into a capillary filled with the SERS-active material. Recently we used such SERS-active capillaries to measure 1 ppb cyanide in water. Here we extend these measurements to nerve agent hydrolysis products using a portable Raman analyzer.

  2. Remote Agent Demonstration

    NASA Technical Reports Server (NTRS)

    Dorais, Gregory A.; Kurien, James; Rajan, Kanna

    1999-01-01

    We describe the computer demonstration of the Remote Agent Experiment (RAX). The Remote Agent is a high-level, model-based, autonomous control agent being validated on the NASA Deep Space 1 spacecraft.

  3. Autonomous sensor manager agents (ASMA)

    NASA Astrophysics Data System (ADS)

    Osadciw, Lisa A.

    2004-04-01

    Autonomous sensor manager agents are presented as an algorithm to perform sensor management within a multisensor fusion network. The design of the hybrid ant system/particle swarm agents is described in detail with some insight into their performance. Although the algorithm is designed for the general sensor management problem, a simulation example involving 2 radar systems is presented. Algorithmic parameters are determined by the size of the region covered by the sensor network, the number of sensors, and the number of parameters to be selected. With straight forward modifications, this algorithm can be adapted for most sensor management problems.

  4. Laser photoacoustic spectroscopy helps fight terrorism: High sensitivity detection of chemical Warfare Agent and explosives

    NASA Astrophysics Data System (ADS)

    Patel, C. K. N.

    2008-01-01

    Tunable laser photoacoustic spectroscopy is maturing rapidly in its applications to real world problems. One of the burning problems of the current turbulent times is the threat of terrorist acts against civilian population. This threat appears in two distinct forms. The first is the potential release of chemical warfare agents (CWA), such as the nerve agents, in a crowded environment. An example of this is the release of Sarin by Aum Shinrikyo sect in a crowded Tokyo subway in 1995. An example of the second terrorist threat is the ever-present possible suicide bomber in crowded environment such as airports, markets and large buildings. Minimizing the impact of both of these threats requires early detection of the presence of the CWAs and explosives. Photoacoustic spectroscopy is an exquisitely sensitive technique for the detection of trace gaseous species, a property that Pranalytica has extensively exploited in its CO2 laser based commercial instrumentation for the sub-ppb level detection of a number of industrially important gases including ammonia, ethylene, acrolein, sulfur hexafluoride, phosphine, arsine, boron trichloride and boron trifluoride. In this presentation, I will focus, however, on our recent use of broadly tunable single frequency high power room temperature quantum cascade lasers (QCL) for the detection of the CWAs and explosives. Using external grating cavity geometry, we have developed room temperature QCLs that produce continuously tunable single frequency CW power output in excess of 300 mW at wavelengths covering 5 μm to 12 μm. I will present data that show a CWA detection capability at ppb levels with false alarm rates below 1:108. I will also show the capability of detecting a variety of explosives at a ppb level, again with very low false alarm rates. Among the explosives, we have demonstrated the capability of detecting homemade explosives such as triacetone triperoxide and its liquid precursor, acetone which is a common household

  5. Factorization of simulations

    SciTech Connect

    Barrett, C. L.; Mortveit, H. S.; Reidys, C. M.

    2001-01-01

    A simulation is collection of agents that, according to some schedule, are making decisions based on information about other agents in that collection. In this paper we present a class of dynamical systems called Sequential Dynamical Systems (SDS) that was developed to capture these key features of computer simulations. Here, as an example of the use of SDS, we demonstrate how one can obtain information about a simulation by a factorization into smaller simulations.

  6. Derivatization of organophosphorus nerve agent degradation products for gas chromatography with ICPMS and TOF-MS detection.

    PubMed

    Richardson, Douglas D; Caruso, Joseph A

    2007-06-01

    Separation and detection of seven V-type (venomous) and G-type (German) organophosphorus nerve agent degradation products by gas chromatography with inductively coupled plasma mass spectrometry (GC-ICPMS) is described. The nonvolatile alkyl phosphonic acid degradation products of interest included ethyl methylphosphonic acid (EMPA, VX acid), isopropyl methylphosphonic acid (IMPA, GB acid), ethyl hydrogen dimethylamidophosphate sodium salt (EDPA, GA acid), isobutyl hydrogen methylphosphonate (IBMPA, RVX acid), as well as pinacolyl methylphosphonic acid (PMPA), methylphosphonic acid (MPA), and cyclohexyl methylphosphonic acid (CMPA, GF acid). N-(tert-Butyldimethylsilyl)-N-methyltrifluroacetamide with 1% TBDMSCl was utilized to form the volatile TBDMS derivatives of the nerve agent degradation products for separation by GC. Exact mass confirmation of the formation of six of the TBDMS derivatives was obtained by GC-time of flight mass spectrometry (TOF-MS). The method developed here allowed for the separation and detection of all seven TBDMS derivatives as well as phosphate in less than ten minutes. Detection limits for the developed method were less than 5 pg with retention times and peak area precisions of less than 0.01 and 6%, respectively. This method was successfully applied to river water and soil matrices. To date this is the first work describing the analysis of chemical warfare agent (CWA) degradation products by GC-ICPMS. PMID:17356819

  7. Spacecraft sanitation agent development

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The development of an effective sanitizing agent that is compatible with the spacecraft environment and the human occupant is discussed. Experimental results show that two sanitation agents must be used to satisfy mission requirements: one agent for personal hygiene and one for equipment maintenance. It was also recommended that a water rinse be used with the agents for best results, and that consideration be given to using the agents pressure packed or in aerosol formulations.

  8. Application of a high surface area solid-phase microextraction air sampling device: collection and analysis of chemical warfare agent surrogate and degradation compounds.

    PubMed

    Stevens, Michael E; Tipple, Christopher A; Smith, Philip A; Cho, David S; Mustacich, Robert V; Eckenrode, Brian A

    2013-09-17

    This work examines a recently improved, dynamic air sampling technique, high surface area solid-phase microextraction (HSA-SPME), developed for time-critical, high-volume sampling and analysis scenarios. The previously reported HSA-SPME sampling device, which provides 10-fold greater surface area compared to commercially available SPME fibers, allowed for an increased analyte uptake per unit time relative to exhaustive sampling through a standard sorbent tube. This sampling device has been improved with the addition of a type-K thermocouple and a custom heater control circuit for direct heating, providing precise (relative standard deviation ∼1%) temperature control of the desorption process for trapped analytes. Power requirements for the HSA-SPME desorption process were 30-fold lower than those for conventional sorbent-bed-based desorption devices, an important quality for a device that could be used for field analysis. Comparisons of the HSA-SPME device when using fixed sampling times for the chemical warfare agent (CWA) surrogate compound, diisopropyl methylphosphonate (DIMP), demonstrated that the HSA-SPME device yielded a greater chromatographic response (up to 50%) relative to a sorbent-bed method. Another HSA-SPME air sampling approach, in which two devices are joined in tandem, was also evaluated for very rapid, low-level, and representative analysis when using discrete sampling times for the compounds of interest. The results indicated that subparts per billion by volume concentration levels of DIMP were detectable with short sampling times (∼15 s). Finally, the tandem HSA-SPME device was employed for the headspace sampling of a CWA degradation compound, 2-(diisopropylaminoethyl) ethyl sulfide, present on cloth material, which demonstrated the capability to detect trace amounts of a CWA degradation product that is estimated to be less volatile than sarin. The rapid and highly sensitive detection features of this device may be beneficial in decision

  9. Antagonistic formation motion of cooperative agents

    NASA Astrophysics Data System (ADS)

    Lu, Wan-Ting; Dai, Ming-Xiang; Xue, Fang-Zheng

    2015-02-01

    This paper investigates a new formation motion problem of a class of first-order multi-agent systems with antagonistic interactions. A distributed formation control algorithm is proposed for each agent to realize the antagonistic formation motion. A sufficient condition is derived to ensure that all of the agents make an antagonistic formation motion in a distributed manner. It is shown that all of the agents can be spontaneously divided into several groups and that agents in the same group collaborate while agents in different groups compete. Finally, a numerical simulation is included to demonstrate our theoretical results. Project supported by the National Natural Science Foundation of China (Grant Nos. 61203080 and 61473051) and the Natural Science Foundation of Chongqing City (Grant No. CSTC 2011BB0081).

  10. Pinning synchronization of a mobile agent network

    NASA Astrophysics Data System (ADS)

    Wang, Lei; Sun, You-xian

    2009-11-01

    We investigate the problem of controlling a group of mobile agents in a plane in order to move them towards a desired orbit via pinning control, in which each agent is associated with a chaotic oscillator coupled with those of neighboring agents, and the pinning strategy is to have the common linear feedback acting on a small fraction of agents by random selection. We explore the effects of the pinning probability, feedback gains and agent density in the pinning synchronization of a mobile agent network under a fast-switching constraint, and perform numerical simulations for validation. In particular, we show that there exists a critical pinning density for network synchronization with an unbounded region: above the threshold, the dynamical network can be controlled by pinning; below it, anarchy prevails. And for the network with a single bounded synchronization region, pinning control has little effect as regards enhancing network synchronizability.

  11. Evolutionary algorithms and multi-agent systems

    NASA Astrophysics Data System (ADS)

    Oh, Jae C.

    2006-05-01

    This paper discusses how evolutionary algorithms are related to multi-agent systems and the possibility of military applications using the two disciplines. In particular, we present a game theoretic model for multi-agent resource distribution and allocation where agents in the environment must help each other to survive. Each agent maintains a set of variables representing actual friendship and perceived friendship. The model directly addresses problems in reputation management schemes in multi-agent systems and Peer-to-Peer distributed systems. We present algorithms based on evolutionary game process for maintaining the friendship values as well as a utility equation used in each agent's decision making. For an application problem, we adapted our formal model to the military coalition support problem in peace-keeping missions. Simulation results show that efficient resource allocation and sharing with minimum communication cost is achieved without centralized control.

  12. Optical recognition of biological agents

    NASA Astrophysics Data System (ADS)

    Baumgart, Chris W.; Linder, Kim Dalton; Trujillo, Josh J.

    2008-04-01

    Differentiation between particulate biological agents and non-biological agents is typically performed via a time-consuming "wet chemistry" process or through the use of fluorescent and spectroscopic analysis. However, while these methods can provide definitive recognition of biological agents, many of them have to be performed in a laboratory environment, or are difficult to implement in the field. Optical recognition techniques offer an additional recognition approach that can provide rapid analysis of a material in-situ to identify those materials that may be biological in nature. One possible application is to use these techniques to "screen" suspicious materials and to identify those that are potentially biological in nature. Suspicious materials identified by this screening process can then be analyzed in greater detail using the other, more definitive (but time consuming) analysis techniques. This presentation will describe the results of a feasibility study to determine whether optical pattern recognition techniques can be used to differentiate biological related materials from non-biological materials. As part of this study, feature extraction algorithms were developed utilizing multiple contrast and texture based features to characterize the macroscopic properties of different materials. In addition, several pattern recognition approaches using these features were tested including cluster analysis and neural networks. Test materials included biological agent simulants, biological agent related materials, and non-biological materials (suspicious white powders). Results of a series of feasibility tests will be presented along with a discussion of the potential field applications for these techniques.

  13. An Immune Agent for Web-Based AI Course

    ERIC Educational Resources Information Center

    Gong, Tao; Cai, Zixing

    2006-01-01

    To overcome weakness and faults of a web-based e-learning course such as Artificial Intelligence (AI), an immune agent was proposed, simulating a natural immune mechanism against a virus. The immune agent was built on the multi-dimension education agent model and immune algorithm. The web-based AI course was comprised of many files, such as HTML…

  14. Nucleophilic Polymers and Gels in Hydrolytic Degradation of Chemical Warfare Agents.

    PubMed

    Bromberg, Lev; Creasy, William R; McGarvey, David J; Wilusz, Eugene; Hatton, T Alan

    2015-10-01

    Water- and solvent-soluble polymeric materials based on polyalkylamines modified with nucleophilic groups are introduced as catalysts of chemical warfare agent (CWA) hydrolysis. A comparative study conducted at constant pH and based on the criteria of the synthetic route simplicity, aqueous solubility, and rate of hydrolysis of CWA mimic, diisopropylfluorophosphate (DFP), indicated that 4-aminopyridine-substituted polyallylamine (PAAm-APy) and polyvinylamine substituted with 4-aminopyridine (PVAm-APy) were advantageous over 4-pyridinealdoxime-modified PVAm and PAAm, poly(butadiene-co-pyrrolidinopyridine), and PAAm modified with bipyridine and its complex with Cu(II). The synthesis of PVAm-APy and PAAm-APy involved generation of a betaine derivative of acrylamide and its covalent attachment onto the polyalkylamine chain followed by basic hydrolysis. Hydrogel particles of PAAm-APy and PVAm-APy cross-linked by epichlorohydrin exhibited pH-dependent swelling and ionization patterns that affected the rate constants of DFP nucleophilic hydrolysis. Deprotonation of the aminopyridine and amine groups increased the rates of the nucleophilic hydrolysis. The second-order rate of nucleophilic hydrolysis was 5.5- to 10-fold higher with the nucleophile-modified gels compared to those obtained by cross-linking of unmodified PAAm, throughout the pH range. Testing of VX and soman (GD) was conducted in 2.5-3.7 wt % PVAm-APy suspensions or gels swollen in water or DMSO/water mixtures. The half-lives of GD in aqueous PVAm-APy were 12 and 770 min at pH 8.5 and 5, respectively. Addition of VX into 3.5-3.7 wt % suspensions of PVAm-APy in DMSO-d6 and D2O at initial VX concentration of 0.2 vol % resulted in 100% VX degradation in less than 20 min. The unmodified PVAm and PAAm were 2 orders of magnitude less active than PVAm-APy and PAAm-APy, with VX half-lives in the range of 24 h. Furthermore, the PVAm-APy and PAAm-APy gels facilitated the dehydrochlorination reaction of sulfur mustard

  15. Direct quantification of chemical warfare agents and related compounds at low ppt levels: comparing active capillary dielectric barrier discharge plasma ionization and secondary electrospray ionization mass spectrometry.

    PubMed

    Wolf, Jan-Christoph; Schaer, Martin; Siegenthaler, Peter; Zenobi, Renato

    2015-01-01

    A novel active capillary dielectric barrier discharge plasma ionization (DBDI) technique for mass spectrometry is applied to the direct detection of 13 chemical warfare related compounds, including sarin, and compared to secondary electrospray ionization (SESI) in terms of selectivity and sensitivity. The investigated compounds include an intact chemical warfare agent and structurally related molecules, hydrolysis products and/or precursors of highly toxic nerve agents (G-series, V-series, and "new" nerve agents), and blistering and incapacitating warfare agents. Well-defined analyte gas phase concentrations were generated by a pressure-assisted nanospray with consecutive thermal evaporation and dilution. Identification was achieved by selected reaction monitoring (SRM). The most abundant fragment ion intensity of each compound was used for quantification. For DBDI and SESI, absolute gas phase detection limits in the low ppt range (in MS/MS mode) were achieved for all compounds investigated. Although the sensitivity of both methods was comparable, the active capillary DBDI sensitivity was found to be dependent on the applied AC voltage, thus enabling direct tuning of the sensitivity and the in-source fragmentation, which may become a key feature in terms of field applicability. Our findings underline the applicability of DBDI and SESI for the direct, sensitive detection and quantification of several CWA types and their degradation products. Furthermore, they suggest the use of DBDI in combination with hand-held instruments for CWAs on-site monitoring. PMID:25427190

  16. Software algorithms for false alarm reduction in LWIR hyperspectral chemical agent detection

    NASA Astrophysics Data System (ADS)

    Manolakis, D.; Model, J.; Rossacci, M.; Zhang, D.; Ontiveros, E.; Pieper, M.; Seeley, J.; Weitz, D.

    2008-04-01

    The long-wave infrared (LWIR) hyperpectral sensing modality is one that is often used for the problem of detection and identification of chemical warfare agents (CWA) which apply to both military and civilian situations. The inherent nature and complexity of background clutter dictates a need for sophisticated and robust statistical models which are then used in the design of optimum signal processing algorithms that then provide the best exploitation of hyperspectral data to ultimately make decisions on the absence or presence of potentially harmful CWAs. This paper describes the basic elements of an automated signal processing pipeline developed at MIT Lincoln Laboratory. In addition to describing this signal processing architecture in detail, we briefly describe the key signal models that form the foundation of these algorithms as well as some spatial processing techniques used for false alarm mitigation. Finally, we apply this processing pipeline to real data measured by the Telops FIRST hyperspectral (FIRST) sensor to demonstrate its practical utility for the user community.

  17. An Adaptive Multi-agent System for Project Schedule Management

    NASA Astrophysics Data System (ADS)

    Shou, Yongyi; Lai, Changtao

    A multi-agent system is established for project schedule management, considering the need for adaptive and dynamic scheduling under uncertainty. The system is realized using Java. In the proposed system, three types of agents, namely activity agents, resource agents, and a monitoring agent, are designed. Duration and resource requirement self-learning operators are developed for activity agents in order to model the self-learning and adaptive capacities of an agent in its local environment; moreover, a monitoring operator is also presented for the monitoring agent. The system allows the user to set up simulation parameters or scheduling rules according to their own preferences. Simulation results from an example showed that the system is effective in supporting users' decision-making process.

  18. Measurement of breakthrough volumes of volatile chemical warfare agents on a poly(2,6-diphenylphenylene oxide)-based adsorbent and application to thermal desorption-gas chromatography/mass spectrometric analysis.

    PubMed

    Kanamori-Kataoka, Mieko; Seto, Yasuo

    2015-09-01

    To establish adequate on-site solvent trapping of volatile chemical warfare agents (CWAs) from air samples, we measured the breakthrough volumes of CWAs on three adsorbent resins by an elution technique using direct electron ionization mass spectrometry. The trapping characteristics of Tenax(®) TA were better than those of Tenax(®) GR and Carboxen(®) 1016. The latter two adsorbents showed non-reproducible breakthrough behavior and low VX recovery. The specific breakthrough values were more than 44 (sarin) L/g Tenax(®) TA resin at 20°C. Logarithmic values of specific breakthrough volume for four nerve agents (sarin, soman, tabun, and VX) showed a nearly linear correlation with the reciprocals of their boiling points, but the data point of sulfur mustard deviated from this linear curve. Next, we developed a method to determine volatile CWAs in ambient air by thermal desorption-gas chromatography (TD-GC/MS). CWA solutions that were spiked into the Tenax TA(®) adsorbent tubes were analyzed by a two-stage TD-GC/MS using a Tenax(®) TA-packed cold trap tube. Linear calibration curves for CWAs retained in the resin tubes were obtained in the range between 0.2pL and 100pL for sarin, soman, tabun, cyclohexylsarin, and sulfur mustard; and between 2pL and 100pL for VX and Russian VX. We also examined the stability of CWAs in Tenax(®) TA tubes purged with either dry or 50% relative humidity air under storage conditions at room temperature or 4°C. More than 80% sarin, soman, tabun, cyclohexylsarin, and sulfur mustard were recovered from the tubes within 2 weeks. In contrast, the recoveries of VX and Russian VX drastically reduced with storage time at room temperature, resulting in a drop to 10-30% after 2 weeks. Moreover, we examined the trapping efficiency of Tenax TA(®) adsorbent tubes for vaporized CWA samples (100mL) prepared in a 500mL gas sampling cylinder. In the concentration range of 0.2-2.5mg/m(3), >50% of sarin, soman, tabun, cyclohexylsarin, and HD were

  19. Hydroxypyridonate chelating agents

    DOEpatents

    Raymond, Kenneth N.; Scarrow, Robert C.; White, David L.

    1987-01-01

    Chelating agents having 1-hydroxy-2-pyridinone (HOPO) and related moieties incorporated within their structures, including polydentate HOPO-substituted polyamines such as spermidine and spermine, and HOPO-substituted desferrioxamine. The chelating agents are useful in selectively removing certain cations from solution, and are particularly useful as ferric ion and actinide chelators. Novel syntheses of the chelating agents are provided.

  20. Mobile Agents Applications.

    ERIC Educational Resources Information Center

    Martins, Rosane Maria; Chaves, Magali Ribeiro; Pirmez, Luci; Rust da Costa Carmo, Luiz Fernando

    2001-01-01

    Discussion of the need to filter and retrieval relevant information from the Internet focuses on the use of mobile agents, specific software components which are based on distributed artificial intelligence and integrated systems. Surveys agent technology and discusses the agent building package used to develop two applications using IBM's Aglet…

  1. Screening of degradation products, impurities and precursors of chemical warfare agents in water and wet or dry organic liquid samples by in-sorbent tube silylation followed by thermal desorption-gas chromatography-mass spectrometry.

    PubMed

    Terzic, Oliver

    2010-07-23

    A standard method used by inspection teams of the Organisation for the Prohibition of Chemical Weapons (OPCW) for preparation of aqueous samples requires several extraction and derivatization steps. This results in tedious and time consuming on-site analysis. A simple thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) method was developed to analyse for a broad range of degradation products, impurities and precursors of chemical warfare agents (CWA) in water solutions and wet or dry organic liquid samples. The method is fast, sensitive, requires only microliter volumes of sample and enables the simultaneous determination of a wide range of compounds with widely differing polarity, volatility and reactivity. The applicability of the method was demonstrated by successful analysis of five OPCW Official Proficiency Test samples. PMID:20541765

  2. Characterization of chemical agent transport in paints.

    PubMed

    Willis, Matthew P; Gordon, Wesley; Lalain, Teri; Mantooth, Brent

    2013-09-15

    A combination of vacuum-based vapor emission measurements with a mass transport model was employed to determine the interaction of chemical warfare agents with various materials, including transport parameters of agents in paints. Accurate determination of mass transport parameters enables the simulation of the chemical agent distribution in a material for decontaminant performance modeling. The evaluation was performed with the chemical warfare agents bis(2-chloroethyl) sulfide (distilled mustard, known as the chemical warfare blister agent HD) and O-ethyl S-[2-(diisopropylamino)ethyl] methylphosphonothioate (VX), an organophosphate nerve agent, deposited on to two different types of polyurethane paint coatings. The results demonstrated alignment between the experimentally measured vapor emission flux and the predicted vapor flux. Mass transport modeling demonstrated rapid transport of VX into the coatings; VX penetrated through the aliphatic polyurethane-based coating (100 μm) within approximately 107 min. By comparison, while HD was more soluble in the coatings, the penetration depth in the coatings was approximately 2× lower than VX. Applications of mass transport parameters include the ability to predict agent uptake, and subsequent long-term vapor emission or contact transfer where the agent could present exposure risks. Additionally, these parameters and model enable the ability to perform decontamination modeling to predict how decontaminants remove agent from these materials. PMID:23872337

  3. Standard Agent Framework 1

    SciTech Connect

    Goldsmith, Steven Y.

    1999-04-06

    The Standard Agent framework provides an extensible object-oriented development environment suitable for use in both research and applications projects. The SAF provides a means for constructing and customizing multi-agent systems through specialization of standard base classes (architecture-driven framework) and by composition of component classes (data driven framework). The standard agent system is implemented as an extensible object-centerd framework. Four concrete base classes are developed: (1) Standard Agency; (2) Standard Agent; (3) Human Factor, and (4) Resources. The object-centered framework developed and utilized provides the best comprimise between generality and flexibility available in agent development systems today.

  4. Can Space Applications Benefit from Intelligent Agents?

    NASA Astrophysics Data System (ADS)

    Varghese, Blesson; McKee, Gerard

    The work reported in this paper proposes a Swarm-Array computing approach based on 'Intelligent Agents' to apply autonomic computing concepts to parallel computing systems and build reliable systems for space applications. Swarm-array computing is a swarm robotics inspired, novel computing approach considered as a path to achieve autonomy in parallel computing systems. In the intelligent agent approach, a task to be executed on parallel computing cores is considered as a swarm of autonomous agents. A task is carried to a computing core by carrier agents and can be seamlessly transferred between cores in the event of a predicted failure, thereby achieving self-* objectives of autonomic computing. The approach is validated on a multi-agent simulator.

  5. Dynamics of adaptive agents with asymmetric information

    NASA Astrophysics Data System (ADS)

    DeMartino, Andrea; Galla, Tobias

    2005-08-01

    We apply path integral techniques to study the dynamics of agent-based models with asymmetric information structures. In particular, we devise a batch version of a model proposed originally by Berg et al (2001 Quantitative Finance 1 203), and convert the coupled multi-agent processes into an effective-agent problem from which the dynamical order parameters in ergodic regimes can be derived self-consistently together with the corresponding phase structure. Our dynamical study complements and extends the available static theory. Results are confirmed by numerical simulations.

  6. Agent Architectures for Compliance

    NASA Astrophysics Data System (ADS)

    Burgemeestre, Brigitte; Hulstijn, Joris; Tan, Yao-Hua

    A Normative Multi-Agent System consists of autonomous agents who must comply with social norms. Different kinds of norms make different assumptions about the cognitive architecture of the agents. For example, a principle-based norm assumes that agents can reflect upon the consequences of their actions; a rule-based formulation only assumes that agents can avoid violations. In this paper we present several cognitive agent architectures for self-monitoring and compliance. We show how different assumptions about the cognitive architecture lead to different information needs when assessing compliance. The approach is validated with a case study of horizontal monitoring, an approach to corporate tax auditing recently introduced by the Dutch Customs and Tax Authority.

  7. Structural characterization of chemical warfare agent degradation products in decontamination solutions with proton band-selective (1)H-(31)P NMR spectroscopy.

    PubMed

    Koskela, Harri; Hakala, Ullastiina; Vanninen, Paula

    2010-06-15

    Decontamination solutions, which are usually composed of strong alkaline chemicals, are used for efficient detoxification of chemical warfare agents (CWAs). The analysis of CWA degradation products directly in decontamination solutions is challenging due to the nature of the matrix. Furthermore, occasionally an unforeseen degradation pathway can result in degradation products which could be eluded to in standard analyses. Here, we present the results of the application of proton band-selective (1)H-(31)P NMR spectroscopy, i.e., band-selective 1D (1)H-(31)P heteronuclear single quantum coherence (HSQC) and band-selective 2D (1)H-(31)P HSQC-total correlation spectroscopy (TOCSY), for ester side chain characterization of organophosphorus nerve agent degradation products in decontamination solutions. The viability of the approach is demonstrated with a test mixture of typical degradation products of nerve agents sarin, soman, and VX. The proton band-selective (1)H-(31)P NMR spectroscopy is also applied in characterization of unusual degradation products of VX in GDS 2000 solution. PMID:20507069

  8. Chemical crowd control agents.

    PubMed

    Menezes, Ritesh G; Hussain, Syed Ather; Rameez, Mansoor Ali Merchant; Kharoshah, Magdy A; Madadin, Mohammed; Anwar, Naureen; Senthilkumaran, Subramanian

    2016-03-01

    Chemical crowd control agents are also referred to as riot control agents and are mainly used by civil authorities and government agencies to curtail civil disobedience gatherings or processions by large crowds. Common riot control agents used to disperse large numbers of individuals into smaller, less destructive, and more easily controllable numbers include chloroacetophenone, chlorobenzylidenemalononitrile, dibenzoxazepine, diphenylaminearsine, and oleoresin capsicum. In this paper, we discuss the emergency medical care needed by sufferers of acute chemical agent contamination and raise important issues concerning toxicology, safety and health. PMID:26658556

  9. Designing Agent Utilities for Coordinated, Scalable and Robust Multi-Agent Systems

    NASA Technical Reports Server (NTRS)

    Tumer, Kagan

    2005-01-01

    Coordinating the behavior of a large number of agents to achieve a system level goal poses unique design challenges. In particular, problems of scaling (number of agents in the thousands to tens of thousands), observability (agents have limited sensing capabilities), and robustness (the agents are unreliable) make it impossible to simply apply methods developed for small multi-agent systems composed of reliable agents. To address these problems, we present an approach based on deriving agent goals that are aligned with the overall system goal, and can be computed using information readily available to the agents. Then, each agent uses a simple reinforcement learning algorithm to pursue its own goals. Because of the way in which those goals are derived, there is no need to use difficult to scale external mechanisms to force collaboration or coordination among the agents, or to ensure that agents actively attempt to appropriate the tasks of agents that suffered failures. To present these results in a concrete setting, we focus on the problem of finding the sub-set of a set of imperfect devices that results in the best aggregate device. This is a large distributed agent coordination problem where each agent (e.g., device) needs to determine whether to be part of the aggregate device. Our results show that the approach proposed in this work provides improvements of over an order of magnitude over both traditional search methods and traditional multi-agent methods. Furthermore, the results show that even in extreme cases of agent failures (i.e., half the agents failed midway through the simulation) the system's performance degrades gracefully and still outperforms a failure-free and centralized search algorithm. The results also show that the gains increase as the size of the system (e.g., number of agents) increases. This latter result is particularly encouraging and suggests that this method is ideally suited for domains where the number of agents is currently in the

  10. Constructing Agent Model for Virtual Training Systems

    NASA Astrophysics Data System (ADS)

    Murakami, Yohei; Sugimoto, Yuki; Ishida, Toru

    Constructing highly realistic agents is essential if agents are to be employed in virtual training systems. In training for collaboration based on face-to-face interaction, the generation of emotional expressions is one key. In training for guidance based on one-to-many interaction such as direction giving for evacuations, emotional expressions must be supplemented by diverse agent behaviors to make the training realistic. To reproduce diverse behavior, we characterize agents by using a various combinations of operation rules instantiated by the user operating the agent. To accomplish this goal, we introduce a user modeling method based on participatory simulations. These simulations enable us to acquire information observed by each user in the simulation and the operating history. Using these data and the domain knowledge including known operation rules, we can generate an explanation for each behavior. Moreover, the application of hypothetical reasoning, which offers consistent selection of hypotheses, to the generation of explanations allows us to use otherwise incompatible operation rules as domain knowledge. In order to validate the proposed modeling method, we apply it to the acquisition of an evacuee's model in a fire-drill experiment. We successfully acquire a subject's model corresponding to the results of an interview with the subject.

  11. Change Agent Survival Guide

    ERIC Educational Resources Information Center

    Dunbar, Folwell L.

    2011-01-01

    Consulting is a rough racket. Only a tarantula hair above IRS agents, meter maids and used car sales people, the profession is a prickly burr for slings and arrows. Throw in education, focus on dysfunctional schools and call oneself a "change agent," and this bad rap all but disappears. Unfortunately, though, consulting/coaching/mentoring in…

  12. Travel Agent Course Outline.

    ERIC Educational Resources Information Center

    British Columbia Dept. of Education, Victoria.

    Written for college entry-level travel agent training courses, this course outline can also be used for inservice training programs offered by travel agencies. The outline provides information on the work of a travel agent and gives clear statements on what learners must be able to do by the end of their training. Material is divided into eight…

  13. A Multi-agent Approach to Distribution System Restoration

    NASA Astrophysics Data System (ADS)

    Nagata, Takeshi; Tao, Yasuhiro; Sasaki, Hiroshi; Fujita, Hideki

    This paper proposes a multi-agent approach to decentralized power system restoration for a distribution system network. The proposed method consists of several Feeder Agents (FAGs) and Load Agents (LAGs). LAG corresponds to the customer load, while a FAG is developed to act as a manager for the decision process. From the simulation results, it can be seen the proposed multi-agent system could reach the right solution by making use of only local information. This means that the proposed multi-agent restoration system is a promising approach to more large-scale distribution networks.

  14. Pediatric Antifungal Agents

    PubMed Central

    Cohen-Wolkowiez, Michael; Moran, Cassandra; Benjamin, Daniel K.; Smith, P Brian

    2009-01-01

    Purpose of review In immunocompromised hosts, invasive fungal infections are common and fatal. In the past decade, the antifungal armamentarium against invasive mycoses has expanded greatly. The purpose of this report is to review the most recent literature addressing the use of antifungal agents in children. Recent findings Most studies evaluating the safety and efficacy of antifungal agents are limited to adults. However, important progress has been made in describing the pharmacokinetics and safety of newer antifungal agents in children, including the echinocandins. Summary Dosage guidelines for newer antifungal agents are currently based on adult and limited pediatric data. Because important developmental pharmacology changes occur throughout childhood impacting the pharmacokinetics of these agents, antifungal studies specifically designed for children are necessary. PMID:19741525

  15. How do agents represent?

    NASA Astrophysics Data System (ADS)

    Ryan, Alex

    Representation is inherent to the concept of an agent, but its importance in complex systems has not yet been widely recognised. In this paper I introduce Peirce's theory of signs, which facilitates a definition of representation in general. In summary, representation means that for some agent, a model is used to stand in for another entity in a way that shapes the behaviour of the agent with respect to that entity. Representation in general is then related to the theories of representation that have developed within different disciplines. I compare theories of representation from metaphysics, military theory and systems theory. Additional complications arise in explaining the special case of mental representations, which is the focus of cognitive science. I consider the dominant theory of cognition — that the brain is a representational device — as well as the sceptical anti-representational response. Finally, I argue that representation distinguishes agents from non-representational objects: agents are objects capable of representation.

  16. Standard Agent Framework 1

    1999-04-06

    The Standard Agent framework provides an extensible object-oriented development environment suitable for use in both research and applications projects. The SAF provides a means for constructing and customizing multi-agent systems through specialization of standard base classes (architecture-driven framework) and by composition of component classes (data driven framework). The standard agent system is implemented as an extensible object-centerd framework. Four concrete base classes are developed: (1) Standard Agency; (2) Standard Agent; (3) Human Factor, and (4)more » Resources. The object-centered framework developed and utilized provides the best comprimise between generality and flexibility available in agent development systems today.« less

  17. Fate of the chemical warfare agent O-ethyl S-2-diisopropylaminoethyl methylphosphonothiolate (VX) on soil following accelerant-based fire and liquid decontamination.

    PubMed

    Gravett, M R; Hopkins, F B; Self, A J; Webb, A J; Timperley, C M; Riches, J R

    2014-08-01

    procedures and analytical methods suitable for investigating accelerant and decontaminant-soaked soil samples are presented. VX and its degradation products and/or impurities were detected under all the conditions studied, demonstrating that accelerant-based fire and liquid-based decontamination and then fire are unlikely to prevent the retrieval of evidence of chemical warfare agent (CWA) testing. This is the first published study of the effects of an accelerant-based fire on a CWA in environmental samples. The results will inform defence and security-based organisations worldwide and support the verification activities of the Organisation for the Prohibition of Chemical Weapons (OPCW), winner of the 2013 Nobel Peace Prize for its extensive efforts to eliminate chemical weapons. PMID:24972874

  18. Engineering Agent Organisations in a Business Environment

    NASA Astrophysics Data System (ADS)

    Traskas, Dimitris; Padget, Julian

    Motivated by demands from the commercial world for software systems that can assist in the reorganisation of processes for the purpose of reducing business complexity, we discuss the benefits and challenges of the multi-agent approach. We concentrate on the engineering aspects of large scale multi-agent systems and begin our exploration by focusing on a real world example from the call centre industry. The critical call routing process seems appropriate and useful in presenting our ideas and provides a good starting point for the development of agent organisations capable of self-management and coordination. The main contributions of this work can be summarised as the demonstration of the value of agent organisational models that do not replicate the typical hierarchical structures observed in human organisations and that a quite basic peer-to-peer structure produces very similar performance indicators to a mature simulator that uses conventional techniques, suggesting further improvements may readily be realized.

  19. NISAC Agent Based Laboratory for Economics

    SciTech Connect

    Downes, Paula; Davis, Chris; Eidson, Eric; Ehlen, Mark; Gieseler, Charles; Harris, Richard

    2006-10-11

    The software provides large-scale microeconomic simulation of complex economic and social systems (such as supply chain and market dynamics of businesses in the US economy) and their dependence on physical infrastructure systems. The system is based on Agent simulation, where each entity of inteest in the system to be modeled (for example, a Bank, individual firms, Consumer households, etc.) is specified in a data-driven sense to be individually repreented by an Agent. The Agents interact using rules of interaction appropriate to their roles, and through those interactions complex economic and social dynamics emerge. The software is implemented in three tiers, a Java-based visualization client, a C++ control mid-tier, and a C++ computational tier.

  20. NISAC Agent Based Laboratory for Economics

    2006-10-11

    The software provides large-scale microeconomic simulation of complex economic and social systems (such as supply chain and market dynamics of businesses in the US economy) and their dependence on physical infrastructure systems. The system is based on Agent simulation, where each entity of inteest in the system to be modeled (for example, a Bank, individual firms, Consumer households, etc.) is specified in a data-driven sense to be individually repreented by an Agent. The Agents interactmore » using rules of interaction appropriate to their roles, and through those interactions complex economic and social dynamics emerge. The software is implemented in three tiers, a Java-based visualization client, a C++ control mid-tier, and a C++ computational tier.« less

  1. Agent-Supported Mission Operations Teamwork

    NASA Technical Reports Server (NTRS)

    Malin, Jane T.

    2003-01-01

    This slide presentation reviews the development of software agents to support of mission operations teamwork. The goals of the work was to make automation by agents easy to use, supervise and direct, manage information and communication to decrease distraction, interruptions, workload and errors, reduce mission impact of off-nominal situations and increase morale and decrease turnover. The accomplishments or the project are: 1. Collaborative agents - mixed initiative and creation of instructions for mediating agent 2. Methods for prototyping, evaluating and evolving socio-technical systems 3. Technology infusion: teamwork tools in mISSIons 4. Demonstrations in simulation testbed An example of the use of agent is given, the use of an agent to monitor a N2 tank leak. An incomplete instruction to the agent is handled with mediating assistants, or Intelligent Briefing and Response Assistant (IBRA). The IBRA Engine also watches data stream for triggers and executes Act-Whenever actions. There is also a Briefing and Response Instruction (BRI) which is easy for a discipline specialist to create through a BRI editor.

  2. Biological warfare agents

    PubMed Central

    Thavaselvam, Duraipandian; Vijayaraghavan, Rajagopalan

    2010-01-01

    The recent bioterrorist attacks using anthrax spores have emphasized the need to detect and decontaminate critical facilities in the shortest possible time. There has been a remarkable progress in the detection, protection and decontamination of biological warfare agents as many instrumentation platforms and detection methodologies are developed and commissioned. Even then the threat of biological warfare agents and their use in bioterrorist attacks still remain a leading cause of global concern. Furthermore in the past decade there have been threats due to the emerging new diseases and also the re-emergence of old diseases and development of antimicrobial resistance and spread to new geographical regions. The preparedness against these agents need complete knowledge about the disease, better research and training facilities, diagnostic facilities and improved public health system. This review on the biological warfare agents will provide information on the biological warfare agents, their mode of transmission and spread and also the detection systems available to detect them. In addition the current information on the availability of commercially available and developing technologies against biological warfare agents has also been discussed. The risk that arise due to the use of these agents in warfare or bioterrorism related scenario can be mitigated with the availability of improved detection technologies. PMID:21829313

  3. Dioxin, agent orange

    SciTech Connect

    Gough, M.

    1986-01-01

    This book presents information on the following topics: dioxin, a prevalent problem; nobody wanted dioxin; agent organe and Vietnam; what we know about and may learn about agent orange and Veterans' health; agent organe and birth defects; dioxin in Missouri; 2, 4, 5-T: the U.S.' disappearing herbicide; Seveso: high-level environmental exposure; the nitro explosion; industrial exposures to dioxin; company behavior in the face of dioxin exposures; dioxin and specific cancers; animal tests of dioxin toxicity; dioxin decions; the present and the future.

  4. Quantum-enhanced deliberation of learning agents using trapped ions

    NASA Astrophysics Data System (ADS)

    Dunjko, V.; Friis, N.; Briegel, H. J.

    2015-02-01

    A scheme that successfully employs quantum mechanics in the design of autonomous learning agents has recently been reported in the context of the projective simulation (PS) model for artificial intelligence. In that approach, the key feature of a PS agent, a specific type of memory which is explored via random walks, was shown to be amenable to quantization, allowing for a speed-up. In this work we propose an implementation of such classical and quantum agents in systems of trapped ions. We employ a generic construction by which the classical agents are ‘upgraded’ to their quantum counterparts by a nested process of adding coherent control, and we outline how this construction can be realized in ion traps. Our results provide a flexible modular architecture for the design of PS agents. Furthermore, we present numerical simulations of simple PS agents which analyze the robustness of our proposal under certain noise models.

  5. Molecular modeling of organophosphorous agents and their aqueous solutions.

    PubMed

    Vishnyakov, Aleksey; Gor, Gennady Yu; Lee, Ming-Tsung; Neimark, Alexander V

    2011-05-26

    Using molecular dynamics simulations, we modeled solvation and diffusion in aqueous solutions of organophosphorous compounds, including nerve G-agents sarin and soman (methylphosphonofluoridates) and their common simulants DMMP (dimethyl methylphosphonate) and DIFP (diisopropyl fluorophosphate). The aqueous solutions of the organophosphorous compounds were found to display complex molecular scale structures and dynamic properties due to competing interactions between strongly hydrophobic and hydrophilic groups. The mixing of agents with water was proved to be exothermic with negative excess mixing volume, indicating a strongly hydrophilic solvation. This effect was confirmed in a specially performed experiment. We discuss to what extent DMMP and DIFP are suitable simulants for G-agents in experimental studies, as far as their interactions with water are concerned. We also focus on the relevance of the structural features and mobilities of agents in water to their interactions with permselective polyelectrolyte membranes that may be employed as protective barriers against chemical warfare agents. PMID:21542641

  6. Agent oriented programming

    NASA Technical Reports Server (NTRS)

    Shoham, Yoav

    1994-01-01

    The goal of our research is a methodology for creating robust software in distributed and dynamic environments. The approach taken is to endow software objects with explicit information about one another, to have them interact through a commitment mechanism, and to equip them with a speech-acty communication language. System-level applications include software interoperation and compositionality. A government application of specific interest is an infrastructure for coordination among multiple planners. Daily activity applications include personal software assistants, such as programmable email, scheduling, and new group agents. Research topics include definition of mental state of agents, design of agent languages as well as interpreters for those languages, and mechanisms for coordination within agent societies such as artificial social laws and conventions.

  7. Radioactive diagnostic agent

    SciTech Connect

    Shigematsu, A.; Aihara, M.; Matsuda, M.; Suzuki, A.; Tsuya, A.

    1984-02-07

    A radioactive diagnostic agent for renal cortex, adrenal cortex, myocardium, brain stem, spinal nerve, etc., which comprises as an essential component monoiodoacetic acid wherein the iodine atom is radioactive.

  8. Riot Control Agents

    MedlinePlus

    ... your clothing, rapidly wash your entire body with soap and water, and get medical care as quickly ... agent from your skin with large amounts of soap and water. Washing with soap and water will ...

  9. 'Dilute-and-shoot' RSLC-MS-MS method for fast detection of nerve and vesicant chemical warfare agent metabolites in urine.

    PubMed

    Rodin, Igor; Braun, Arcady; Stavrianidi, Andrey; Baygildiev, Timur; Shpigun, Oleg; Oreshkin, Dmitry; Rybalchenko, Igor

    2015-01-01

    A sensitive screening method based on fast liquid chromatography tandem mass-spectrometry (RSLC-MS-MS) has shown the feasibility of separation and detection of low concentration β-lyase metabolites of sulfur mustard and of nerve agent phosphonic acids in urine. The analysis of these compounds is of interest because they are specific metabolites of the chemical warfare agents (CWAs), sulfur mustard (HD), sarin (GB), soman (GD), VX and Russian VX (RVX). The 'dilute-and-shoot' RSLC-MS-MS method provides a sensitive and direct approach for determining CWA exposure in non-extracted non-derivatized samples from urine. Chromatographic separation of the metabolites was achieved using a reverse phase column with gradient mobile phases consisting of 0.5% formic acid in water and acetonitrile. Identification and quantification of species were achieved using electrospray ionization-tandem mass-spectrometry monitoring two precursor-to-product ion transitions for each compound. The method demonstrates linearity over at least two orders of magnitude and had detection limits of 0.5 ng/mL in urine. PMID:25326204

  10. Cutaneous challenge with chemical warfare agents in the SKH-1 hairless mouse. (I) Development of a model for screening studies in skin decontamination and protection.

    PubMed

    Dorandeu, F; Taysse, L; Boudry, I; Foquin, A; Hérodin, F; Mathieu, J; Daulon, S; Cruz, C; Lallement, G

    2011-06-01

    Exposure to lethal chemical warfare agents (CWAs) is no longer only a military issue due to the terrorist threat. Among the CWAs of concern are the organophosphorus nerve agent O-ethyl-S-(2[di-isopropylamino]ethyl)methyl-phosphonothioate (VX) and the vesicant sulfur mustard (SM). Although efficient means of decontamination are available, most of them lose their efficacy when decontamination is delayed after exposure of the bare skin. Alternatively, CWA skin penetration can be prevented by topical skin protectants. Active research in skin protection and decontamination is thus paramount. In vivo screening of decontaminants or skin protectants is usually time consuming and may be expensive depending on the animal species used. We were thus looking for a suitable, scientifically sound and cost-effective model, which is easy to handle. The euthymic hairless mouse Crl: SKH-1 (hr/hr) BR is widely used in some skin studies and has previously been described to be suitable for some experiments involving SM or SM analogs. To evaluate the response of this species, we studied the consequences of exposing male anaesthetized SKH-1 mice to either liquid VX or to SM, the latter being used in liquid form or as saturated vapours. Long-term effects of SM burn were also evaluated. The model was then used in the companion paper (Taysse et al.(1)). PMID:20547654

  11. Development of a liquid chromatography-multiple reaction monitoring procedure for concurrent verification of exposure to different forms of mustard agents.

    PubMed

    Yeo, Thong-Hiang; Ho, Mer-Lin; Loke, Weng-Keong

    2008-01-01

    A novel liquid chromatography-multiple reaction monitoring (LC-MRM) procedure has been developed for retrospective diagnosis of exposure to different forms of mustard agents. This concise method is able to validate prior exposure to nitrogen mustards (HN-1, HN-2, and HN-3) or sulfur mustard (HD) in a single run, which significantly reduces analysis time compared to separate runs to screen for different mustards' biomarkers based on tandem mass spectrometry. Belonging to one of the more toxic classes of chemical warfare agents, these potent vesicants bind covalently to the cysteine-34 residue of human serum albumin. This results in the formation of stable adducts whose identities were confirmed by a de novo sequencing bioinformatics software package. Our developed technique tracks these albumin-derived adduct biomarkers in blood samples which persist in vitro following exposure, enabling a detection limit of 200 nM of HN-1, 100 nM of HN-2, 200 nM of HN-3, or 50 nM of HD in human blood. The CWA-adducts formed in blood samples can be conveniently and sensitively analyzed by this MRM technique to allow rapid and reliable screening. PMID:18269793

  12. An Agent-Based Cockpit Task Management System

    NASA Technical Reports Server (NTRS)

    Funk, Ken

    1997-01-01

    An agent-based program to facilitate Cockpit Task Management (CTM) in commercial transport aircraft is developed and evaluated. The agent-based program called the AgendaManager (AMgr) is described and evaluated in a part-task simulator study using airline pilots.

  13. Learning by Communicating in Natural Language with Conversational Agents

    ERIC Educational Resources Information Center

    Graesser, Arthur; Li, Haiying; Forsyth, Carol

    2014-01-01

    Learning is facilitated by conversational interactions both with human tutors and with computer agents that simulate human tutoring and ideal pedagogical strategies. In this article, we describe some intelligent tutoring systems (e.g., AutoTutor) in which agents interact with students in natural language while being sensitive to their cognitive…

  14. Nanomotors responsive to nerve-agent vapor plumes.

    PubMed

    Singh, Virendra V; Kaufmann, Kevin; Esteban-Fernández de Ávila, Berta; Uygun, Murat; Wang, Joseph

    2016-02-25

    Enzyme-powered nanomotors responsive to the presence of nerve agents in the surrounding atmosphere are employed for remote detection of chemical vapor threats. Distinct changes in the propulsion behavior, associated with the partition of the sarin simulant diethyl chlorophosphate (DCP), offer reliable and rapid detection of the nerve-agent vapor threat. PMID:26824395

  15. Agents: An approach for dynamic process modelling

    NASA Astrophysics Data System (ADS)

    Grohmann, Axel; Kopetzky, Roland; Lurk, Alexander

    1999-03-01

    With the growing amount of distributed and heterogeneous information and services, conventional information systems have come to their limits. This gave rise to the development of a Multi-Agent System (the "Logical Client") which can be used in complex information systems as well as in other advanced software systems. Computer agents are proactive, reactive and social. They form a community of independent software components that can communicate and co-operate in order to accomplish complex tasks. Thus the agent-oriented paradigm provides a new and powerful approach to programming distributed systems. The communication framework developed is based on standards like CORBA, KQML and KIF. It provides an embedded rule based system to find adequate reactions to incoming messages. The macro-architecture of the Logical Client consists of independent agents and uses artificial intelligence to cope with complex patterns of communication and actions. A set of system agents is also provided, including the Strategy Service as a core component for modelling processes at runtime, the Computer Supported Cooperative Work (CSCW) Component for supporting remote co-operation between human users and the Repository for managing and hiding the file based data flow in heterogeneous networks. This architecture seems to be capable of managing complexity in information systems. It is also being implemented in a complex simulation system that monitors and simulates the environmental radioactivity in the country Baden-Württemberg.

  16. Nondestructive Intervention to Multi-Agent Systems through an Intelligent Agent

    PubMed Central

    Han, Jing; Wang, Lin

    2013-01-01

    For a given multi-agent system where the local interaction rule of the existing agents can not be re-designed, one way to intervene the collective behavior of the system is to add one or a few special agents into the group which are still treated as normal agents by the existing ones. We study how to lead a Vicsek-like flocking model to reach synchronization by adding special agents. A popular method is to add some simple leaders (fixed-headings agents). However, we add one intelligent agent, called ‘shill’, which uses online feedback information of the group to decide the shill's moving direction at each step. A novel strategy for the shill to coordinate the group is proposed. It is strictly proved that a shill with this strategy and a limited speed can synchronize every agent in the group. The computer simulations show the effectiveness of this strategy in different scenarios, including different group sizes, shill speed, and with or without noise. Compared to the method of adding some fixed-heading leaders, our method can guarantee synchronization for any initial configuration in the deterministic scenario and improve the synchronization level significantly in low density groups, or model with noise. This suggests the advantage and power of feedback information in intervention of collective behavior. PMID:23658695

  17. Bidding Agents That Perpetrate Auction Fraud

    NASA Astrophysics Data System (ADS)

    Trevathan, Jarrod; McCabe, Alan; Read, Wayne

    This paper presents a software bidding agent that inserts fake bids on the seller's behalf to inflate an auction's price. This behaviour is referred to as shill bidding. Shill bidding is strictly prohibited by online auctioneers, as it defrauds unsuspecting buyers by forcing them to pay more for the item. The malicious bidding agent was constructed to aid in developing shill detection techniques. We have previously documented a simple shill bidding agent that incrementally increases the auction price until it reaches the desired profit target, or it becomes too risky to continue bidding. This paper presents an adaptive shill bidding agent which when used over a series of auctions with substitutable items, can revise its strategy based on bidding behaviour in past auctions. The adaptive agent applies a novel prediction technique referred to as the Extremum Consistency (EC) algorithm, to determine the optimal price to aspire for. The EC algorithm has successfully been used in handwritten signature verification for determining the maximum and minimum values in an input stream. The agent's ability to inflate the price has been tested in a simulated marketplace and experimental results are presented.

  18. Output regulation of switched linear multi-agent systems: an agent-dependent average dwell time method

    NASA Astrophysics Data System (ADS)

    Jia, Hongwei; Zhao, Jun

    2016-08-01

    The output regulation problem of switched linear multi-agent systems with stabilisable and unstabilisable subsystems is investigated in this paper. A sufficient condition for the solvability of the problem is given. Owing to the characteristics of switched multi-agent systems, even if each agent has its own dwell time, the multi-agent systems, if viewed as an overall switched system, may not have a dwell time. To overcome this difficulty, we present a new approach, called an agent-dependent average dwell time method. Due to the limited information exchange between agents, a distributed dynamic observer network for agents is provided. Further, a distributed dynamic controller based on observer is designed. Finally, simulation results show the effectiveness of the proposed solutions.

  19. Non-halogenated alternative cleaning agents

    SciTech Connect

    Nigrey, P.J.

    1992-01-01

    The cleaning efficiency of five alternative cleaning agents have been evaluated as possible replacements chlorofluorocarbon (CFC) and chlorohydrocarbon (CHC) solvents used in the manufacture of certain electronic components. These cleaning agents were evaluated in the first phase (Phase I) of a two-phase program to remove various simulated manufacturing contaminants such as oils, greases, mold release, and body oils. Results showed that a decyl acetate (EXXATE 1000) and a terpene (BIOACT EC-7) were both able to effectively remove these contaminants form copper board substrates.

  20. Non-halogenated alternative cleaning agents

    SciTech Connect

    Nigrey, P.J.

    1992-09-01

    The cleaning efficiency of five alternative cleaning agents have been evaluated as possible replacements chlorofluorocarbon (CFC) and chlorohydrocarbon (CHC) solvents used in the manufacture of certain electronic components. These cleaning agents were evaluated in the first phase (Phase I) of a two-phase program to remove various simulated manufacturing contaminants such as oils, greases, mold release, and body oils. Results showed that a decyl acetate (EXXATE 1000) and a terpene (BIOACT EC-7) were both able to effectively remove these contaminants form copper board substrates.

  1. A Diversified Investment Strategy Using Autonomous Agents

    NASA Astrophysics Data System (ADS)

    Barbosa, Rui Pedro; Belo, Orlando

    In a previously published article, we presented an architecture for implementing agents with the ability to trade autonomously in the Forex market. At the core of this architecture is an ensemble of classification and regression models that is used to predict the direction of the price of a currency pair. In this paper, we will describe a diversified investment strategy consisting of five agents which were implemented using that architecture. By simulating trades with 18 months of out-of-sample data, we will demonstrate that data mining models can produce profitable predictions, and that the trading risk can be diminished through investment diversification.

  2. Agent Based Modeling Applications for Geosciences

    NASA Astrophysics Data System (ADS)

    Stein, J. S.

    2004-12-01

    Agent-based modeling techniques have successfully been applied to systems in which complex behaviors or outcomes arise from varied interactions between individuals in the system. Each individual interacts with its environment, as well as with other individuals, by following a set of relatively simple rules. Traditionally this "bottom-up" modeling approach has been applied to problems in the fields of economics and sociology, but more recently has been introduced to various disciplines in the geosciences. This technique can help explain the origin of complex processes from a relatively simple set of rules, incorporate large and detailed datasets when they exist, and simulate the effects of extreme events on system-wide behavior. Some of the challenges associated with this modeling method include: significant computational requirements in order to keep track of thousands to millions of agents, methods and strategies of model validation are lacking, as is a formal methodology for evaluating model uncertainty. Challenges specific to the geosciences, include how to define agents that control water, contaminant fluxes, climate forcing and other physical processes and how to link these "geo-agents" into larger agent-based simulations that include social systems such as demographics economics and regulations. Effective management of limited natural resources (such as water, hydrocarbons, or land) requires an understanding of what factors influence the demand for these resources on a regional and temporal scale. Agent-based models can be used to simulate this demand across a variety of sectors under a range of conditions and determine effective and robust management policies and monitoring strategies. The recent focus on the role of biological processes in the geosciences is another example of an area that could benefit from agent-based applications. A typical approach to modeling the effect of biological processes in geologic media has been to represent these processes in

  3. Development of the HS-SPME-GC-MS/MS method for analysis of chemical warfare agent and their degradation products in environmental samples.

    PubMed

    Nawała, Jakub; Czupryński, Krzysztof; Popiel, Stanisław; Dziedzic, Daniel; Bełdowski, Jacek

    2016-08-24

    After World War II approximately 50,000 tons of chemical weapons were dumped in the Baltic Sea by the Soviet Union under the provisions of the Potsdam Conference on Disarmament. These dumped chemical warfare agents still possess a major threat to the marine environment and to human life. Therefore, continue monitoring of these munitions is essential. In this work, we present the application of new solid phase microextraction fibers in analysis of chemical warfare agents and their degradation products. It can be concluded that the best fiber for analysis of sulfur mustard and its degradation products is butyl acrylate (BA), whereas for analysis of organoarsenic compounds and chloroacetophenone, the best fiber is a co-polymer of methyl acrylate and methyl methacrylate (MA/MMA). In order to achieve the lowest LOD and LOQ the samples should be divided into two subsamples. One of them should be analyzed using a BA fiber, and the second one using a MA/MMA fiber. When the fast analysis is required, the microextraction should be performed by use of a butyl acrylate fiber because the extraction efficiency of organoarsenic compounds for this fiber is acceptable. Next, we have elaborated of the HS-SPME-GC-MS/MS method for analysis of CWA degradation products in environmental samples using laboratory obtained fibers The analytical method for analysis of organosulfur and organoarsenic compounds was optimized and validated. The LOD's for all target chemicals were between 0.03 and 0.65 ppb. Then, the analytical method developed by us, was used for the analysis of sediment and pore water samples from the Baltic Sea. During these studies, 80 samples were analyzed. It was found that 25 sediments and 5 pore water samples contained CWA degradation products such as 1,4-dithiane, 1,4-oxathiane or triphenylarsine, the latter being a component of arsine oil. The obtained data is evidence that the CWAs present in the Baltic Sea have leaked into the general marine environment. PMID

  4. Agent independent task planning

    NASA Technical Reports Server (NTRS)

    Davis, William S.

    1990-01-01

    Agent-Independent Planning is a technique that allows the construction of activity plans without regard to the agent that will perform them. Once generated, a plan is then validated and translated into instructions for a particular agent, whether a robot, crewmember, or software-based control system. Because Space Station Freedom (SSF) is planned for orbital operations for approximately thirty years, it will almost certainly experience numerous enhancements and upgrades, including upgrades in robotic manipulators. Agent-Independent Planning provides the capability to construct plans for SSF operations, independent of specific robotic systems, by combining techniques of object oriented modeling, nonlinear planning and temporal logic. Since a plan is validated using the physical and functional models of a particular agent, new robotic systems can be developed and integrated with existing operations in a robust manner. This technique also provides the capability to generate plans for crewmembers with varying skill levels, and later apply these same plans to more sophisticated robotic manipulators made available by evolutions in technology.

  5. Electric power market agent design

    NASA Astrophysics Data System (ADS)

    Oh, Hyungseon

    The electric power industry in many countries has been restructured in the hope of a more economically efficient system. In the restructured system, traditional operating and planning tools based on true marginal cost do not perform well since information required is strictly confidential. For developing a new tool, it is necessary to understand offer behavior. The main objective of this study is to create a new tool for power system planning. For the purpose, this dissertation develops models for a market and market participants. A new model is developed in this work for explaining a supply-side offer curve, and several variables are introduced to characterize the curve. Demand is estimated using a neural network, and a numerical optimization process is used to determine the values of the variables that maximize the profit of the agent. The amount of data required for the optimization is chosen with the aid of nonlinear dynamics. To suggest an optimal demand-side bidding function, two optimization problems are constructed and solved for maximizing consumer satisfaction based on the properties of two different types of demands: price-based demand and must-be-served demand. Several different simulations are performed to test how an agent reacts in various situations. The offer behavior depends on locational benefit as well as the offer strategies of competitors.

  6. MpcAgent

    SciTech Connect

    Nutaro, James

    2013-11-29

    MpcAgent software is a module for the VolltronLite platform from PNNL that regulates the operation of rooftop air conditioning units in small to medium commercial buildings for the purpose of reducing peak power consumption. The MpcAgent accomplishes this by restricting the number of units that may operate simultaneously and using a model predictive control strategy to select which units to operate in each control period. The outcome of this control is effective control of the building air temperature at the user specified set point while avoiding expensive peak demand charges that result from running all HVAC units simultaneously.

  7. MpcAgent

    2013-11-29

    MpcAgent software is a module for the VolltronLite platform from PNNL that regulates the operation of rooftop air conditioning units in small to medium commercial buildings for the purpose of reducing peak power consumption. The MpcAgent accomplishes this by restricting the number of units that may operate simultaneously and using a model predictive control strategy to select which units to operate in each control period. The outcome of this control is effective control of themore » building air temperature at the user specified set point while avoiding expensive peak demand charges that result from running all HVAC units simultaneously.« less

  8. Gadofullerene MRI contrast agents.

    PubMed

    Bolskar, Robert D

    2008-04-01

    A promising new class of MRI contrast-enhancing agents with high relaxivities is based on gadolinium-containing metallofullerenes, which are also termed gadofullerenes. Detailed study of the water-proton relaxivity properties and intermolecular nanoclustering behavior of gadofullerene derivatives has revealed valuable information about their relaxivity mechanisms and given a deeper understanding of this new class of paramagnetic contrast agent. Here, the latest findings on water-solubilized gadofullerene materials and how these findings relate to their future applications in MRI are reviewed and discussed. PMID:18373426

  9. Model of mobile agents for sexual interactions networks

    NASA Astrophysics Data System (ADS)

    González, M. C.; Lind, P. G.; Herrmann, H. J.

    2006-02-01

    We present a novel model to simulate real social networks of complex interactions, based in a system of colliding particles (agents). The network is build by keeping track of the collisions and evolves in time with correlations which emerge due to the mobility of the agents. Therefore, statistical features are a consequence only of local collisions among its individual agents. Agent dynamics is realized by an event-driven algorithm of collisions where energy is gained as opposed to physical systems which have dissipation. The model reproduces empirical data from networks of sexual interactions, not previously obtained with other approaches.

  10. Exploring cooperation and competition using agent-based modeling

    PubMed Central

    Elliott, Euel; Kiel, L. Douglas

    2002-01-01

    Agent-based modeling enhances our capacity to model competitive and cooperative behaviors at both the individual and group levels of analysis. Models presented in these proceedings produce consistent results regarding the relative fragility of cooperative regimes among agents operating under diverse rules. These studies also show how competition and cooperation may generate change at both the group and societal level. Agent-based simulation of competitive and cooperative behaviors may reveal the greatest payoff to social science research of all agent-based modeling efforts because of the need to better understand the dynamics of these behaviors in an increasingly interconnected world. PMID:12011396

  11. Adaptivity in Agent-Based Routing for Data Networks

    NASA Technical Reports Server (NTRS)

    Wolpert, David H.; Kirshner, Sergey; Merz, Chris J.; Turner, Kagan

    2000-01-01

    Adaptivity, both of the individual agents and of the interaction structure among the agents, seems indispensable for scaling up multi-agent systems (MAS s) in noisy environments. One important consideration in designing adaptive agents is choosing their action spaces to be as amenable as possible to machine learning techniques, especially to reinforcement learning (RL) techniques. One important way to have the interaction structure connecting agents itself be adaptive is to have the intentions and/or actions of the agents be in the input spaces of the other agents, much as in Stackelberg games. We consider both kinds of adaptivity in the design of a MAS to control network packet routing. We demonstrate on the OPNET event-driven network simulator the perhaps surprising fact that simply changing the action space of the agents to be better suited to RL can result in very large improvements in their potential performance: at their best settings, our learning-amenable router agents achieve throughputs up to three and one half times better than that of the standard Bellman-Ford routing algorithm, even when the Bellman-Ford protocol traffic is maintained. We then demonstrate that much of that potential improvement can be realized by having the agents learn their settings when the agent interaction structure is itself adaptive.

  12. Autonomous Formations of Multi-Agent Systems

    NASA Technical Reports Server (NTRS)

    Dhali, Sanjana; Joshi, Suresh M.

    2013-01-01

    Autonomous formation control of multi-agent dynamic systems has a number of applications that include ground-based and aerial robots and satellite formations. For air vehicles, formation flight ("flocking") has the potential to significantly increase airspace utilization as well as fuel efficiency. This presentation addresses two main problems in multi-agent formations: optimal role assignment to minimize the total cost (e.g., combined distance traveled by all agents); and maintaining formation geometry during flock motion. The Kuhn-Munkres ("Hungarian") algorithm is used for optimal assignment, and consensus-based leader-follower type control architecture is used to maintain formation shape despite the leader s independent movements. The methods are demonstrated by animated simulations.

  13. Agent Persuasion Mechanism of Acquaintance

    NASA Astrophysics Data System (ADS)

    Jinghua, Wu; Wenguang, Lu; Hailiang, Meng

    Agent persuasion can improve negotiation efficiency in dynamic environment based on its initiative and autonomy, and etc., which is being affected much more by acquaintance. Classification of acquaintance on agent persuasion is illustrated, and the agent persuasion model of acquaintance is also illustrated. Then the concept of agent persuasion degree of acquaintance is given. Finally, relative interactive mechanism is elaborated.

  14. 13 CFR 107.1620 - Functions of agents, including Central Registration Agent, Selling Agent and Fiscal Agent.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Functions of agents, including Central Registration Agent, Selling Agent and Fiscal Agent. 107.1620 Section 107.1620 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION SMALL BUSINESS INVESTMENT COMPANIES SBA Financial Assistance...

  15. 13 CFR 108.1620 - Functions of agents, including Central Registration Agent, Selling Agent and Fiscal Agent.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Functions of agents, including Central Registration Agent, Selling Agent and Fiscal Agent. 108.1620 Section 108.1620 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION NEW MARKETS VENTURE CAPITAL (âNMVCâ) PROGRAM SBA...

  16. Laser-based instrumentation for the detection of chemical agents

    SciTech Connect

    Hartford, A. Jr.; Sander, R.K.; Quigley, G.P.; Radziemski, L.J.; Cremers, D.A.

    1982-01-01

    Several laser-based techniques are being evaluated for the remote, point, and surface detection of chemical agents. Among the methods under investigation are optoacoustic spectroscopy, laser-induced breakdown spectroscopy (LIBS), and synchronous detection of laser-induced fluorescence (SDLIF). Optoacoustic detection has already been shown to be capable of extremely sensitive point detection. Its application to remote sensing of chemical agents is currently being evaluated. Atomic emission from the region of a laser-generated plasma has been used to identify the characteristic elements contained in nerve (P and F) and blister (S and Cl) agents. Employing this LIBS approach, detection of chemical agent simulants dispersed in air and adsorbed on a variety of surfaces has been achieved. Synchronous detection of laser-induced fluorescence provides an attractive alternative to conventional LIF, in that an artificial narrowing of the fluorescence emission is obtained. The application of this technique to chemical agent simulants has been successfully demonstrated. 19 figures.

  17. Probing the role of P dbnd O stretching mode enhancement in nerve-agent sensors: Simulation of the adsorption of diisopropylfluorophosphate on the model MgO and CaO surfaces

    NASA Astrophysics Data System (ADS)

    Kolodziejczyk, Wojciech; Majumdar, D.; Roszak, Szczepan; Leszczynski, Jerzy

    2007-12-01

    The interactions of diisopropylfluorophosphate (DFP) with model MgO and CaO surfaces have been investigated using density functional (DFT) and Møller-Plesset second order perturbation techniques. The geometries were fully optimized at the DFT level. The calculated interaction energies and the corresponding thermodynamic properties show that DFP is physisorbed on these two model oxide surfaces and adsorption on the MgO surface is stronger. Analyses of the calculated IR and Raman spectra point to the enhancement of the P dbnd O stretching mode with respect to the isolated DFP and this property could be used to detect nerve-agents using surface-enhanced Raman spectroscopy.

  18. Can Subscription Agents Survive?

    ERIC Educational Resources Information Center

    Tuttle, Marcia

    1985-01-01

    With the saturation of traditional markets for their services, subscription agents have evolved from orders and invoices to serving customers by communicating with librarians and publishers and making automated and paper products available. Magazine fulfillment centers, publisher discounts, and electronic publishing will influence the subscription…

  19. Remote Agent Experiment

    NASA Technical Reports Server (NTRS)

    Benard, Doug; Dorais, Gregory A.; Gamble, Ed; Kanefsky, Bob; Kurien, James; Millar, William; Muscettola, Nicola; Nayak, Pandu; Rouquette, Nicolas; Rajan, Kanna; Norvig, Peter (Technical Monitor)

    2000-01-01

    Remote Agent (RA) is a model-based, reusable artificial intelligence (At) software system that enables goal-based spacecraft commanding and robust fault recovery. RA was flight validated during an experiment on board of DS1 between May 17th and May 21th, 1999.

  20. E-Learning Agents

    ERIC Educational Resources Information Center

    Gregg, Dawn G.

    2007-01-01

    Purpose: The purpose of this paper is to illustrate the advantages of using intelligent agents to facilitate the location and customization of appropriate e-learning resources and to foster collaboration in e-learning environments. Design/methodology/approach: This paper proposes an e-learning environment that can be used to provide customized…

  1. Battlefield agent collaboration

    NASA Astrophysics Data System (ADS)

    Budulas, Peter P.; Young, Stuart H.; Emmerman, Philip J.

    2001-09-01

    Small air and ground physical agents (robots) will be ubiquitous on the battlefield of the 21st century, principally to lower the exposure to harm of our ground forces in urban and open terrain scenarios. Teams of small collaborating physical agents conducting tasks such as Reconnaissance, Surveillance, and Target Acquisition (RSTA), intelligence, chemical and biological agent detection, logistics, decoy, sentry; and communications relay will have advanced sensors, communications, and mobility characteristics. It is anticipated that there will be many levels of individual and team collaboration between the soldier and robot, robot to robot, and robot to mother ship. This paper presents applications and infrastructure components that illustrate each of these levels. As an example, consider the application where a team of twenty small robots must rapidly explore and define a building complex. Local interactions and decisions require peer to peer collaboration. Global direction and information fusion warrant a central team control provided by a mother ship. The mother ship must effectively deliver/retrieve, service, and control these robots as well as fuse the information gathered by these highly mobile robot teams. Any level of collaboration requires robust communications, specifically a mobile ad hoc network. The application of fixed ground sensors and mobile robots is also included in this paper. This paper discusses on going research at the U.S. Army Research Laboratory that supports the development of multi-robot collaboration. This research includes battlefield visualization, intelligent software agents, adaptive communications, sensor and information fusion, and multi-modal human computer interaction.

  2. Mobility control agent

    SciTech Connect

    Argabright, P.A.; Phillips, B.L.; Rhudy, J.S.

    1983-05-17

    Polymer mobility control agents useful in supplemental oil recovery processes, which give improved reciprocal relative mobilities, are prepared by initiating the polymerization of a monomer containing a vinyl group with a catalyst comprising a persulfate and ferrous ammonium sulfate. The vinyl monomer is an acrylyl, a vinyl cyanide, a styryl and water soluble salts thereof.

  3. Agent Based Intelligence in a Tetrahedral Rover

    NASA Technical Reports Server (NTRS)

    Phelps, Peter; Truszkowski, Walt

    2007-01-01

    A tetrahedron is a 4-node 6-strut pyramid structure which is being used by the NASA - Goddard Space Flight Center as the basic building block for a new approach to robotic motion. The struts are extendable; it is by the sequence of activities: strut-extension, changing the center of gravity and falling that the tetrahedron "moves". Currently, strut-extension is handled by human remote control. There is an effort underway to make the movement of the tetrahedron autonomous, driven by an attempt to achieve a goal. The approach being taken is to associate an intelligent agent with each node. Thus, the autonomous tetrahedron is realized as a constrained multi-agent system, where the constraints arise from the fact that between any two agents there is an extendible strut. The hypothesis of this work is that, by proper composition of such automated tetrahedra, robotic structures of various levels of complexity can be developed which will support more complex dynamic motions. This is the basis of the new approach to robotic motion which is under investigation. A Java-based simulator for the single tetrahedron, realized as a constrained multi-agent system, has been developed and evaluated. This paper reports on this project and presents a discussion of the structure and dynamics of the simulator.

  4. Agent-Based Modeling in Systems Pharmacology.

    PubMed

    Cosgrove, J; Butler, J; Alden, K; Read, M; Kumar, V; Cucurull-Sanchez, L; Timmis, J; Coles, M

    2015-11-01

    Modeling and simulation (M&S) techniques provide a platform for knowledge integration and hypothesis testing to gain insights into biological systems that would not be possible a priori. Agent-based modeling (ABM) is an M&S technique that focuses on describing individual components rather than homogenous populations. This tutorial introduces ABM to systems pharmacologists, using relevant case studies to highlight how ABM-specific strengths have yielded success in the area of preclinical mechanistic modeling. PMID:26783498

  5. Adding ecosystem function to agent-based land use models

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this paper is to examine issues in the inclusion of simulations of ecosystem functions in agent-based models of land use decision-making. The reasons for incorporating these simulations include local interests in land fertility and global interests in carbon sequestration. Biogeoche...

  6. Groundwater Infiltration Path of Road Deicing Agent and its Quantification

    NASA Astrophysics Data System (ADS)

    Moroizumi, T.; Hada, J.; Sasaki, K.

    2015-12-01

    A deicing agent has been sprinkled on an expressway to prevent it from freezing in the hilly and mountainous area along the expressway having been used for more than 30 years. We investigated the infiltration, the river runoff, and the scattering of the de-icing agent quantitatively, observed the variation of water quality in river, and discussed the infiltration route and balance of the deicing agent in order to clarify the influence of the de-icing agent on the groundwater salinization. As a result, it turned out that 65% of the de-icing agent sprinkled on the road surface flowed into the waterway, the 25% infiltrated into underground through the crack of a road surface, and the remaining 10% dispersed out of an expressway. Next, for the rate of the de-icing agent outflowing to the river during a frozen snow term, it was estimated that the 39% of the sprinkled de-icing agent outflowed with surface water, and the 17% did with groundwater. Moreover, it was shown clearly that the 44% was probably stored in underground from the balance between the sprinkled de-icing agent and the outflowing one. In addition, the Cl- concentration of groundwater by the infiltrated deicing agent was simulated to clarify its extent and to predict its change in future when stopped sprinkling the deicing agent.

  7. A local flocking algorithm of multi-agent dynamic systems

    NASA Astrophysics Data System (ADS)

    Pei, Huiqin; Chen, Shiming; Lai, Qiang

    2015-11-01

    In this paper, the local flocking of multi-agent systems is investigated, which means all agents form some groups of surrounding multiple targets with the partial information exchange. For the purpose of realising local multi-flocking, a control algorithm of local flocking is proposed, which is a biologically inspired approach that assimilates key characteristics of flocking and anti-flocking. In the process of surrounding mobile targets through the control algorithm, all agents can adaptively choose between two work modes to depend on the variation of visual field and the number of pursuing agents with the mobile target. One is a flocking pursuing mode which is that some agents pursue each mobile target, the other is an anti-flocking searching mode that means with the exception of the pursing agents of mobile targets, other agents respectively hunt for optimal the mobile target with a closest principle between the agent and the target. In two work modes, the agents are controlled severally via the different control protocol. By the Lyapunov theorem, the stability of the second-order multi-agent system is proven in detail. Finally, simulation results verify the effectiveness of the proposed algorithm.

  8. Distributed Agents for Autonomy

    NASA Astrophysics Data System (ADS)

    Blake, Rick; Amigoni, Francesco; Brambilla, Andrea; de la Rosa Steinz, Sonia; Lavagna, Michele; le Duc, Ian; Page, Jonathan; Page, Oliver; Steel, Robin; Wijnands, Quirien

    2010-08-01

    The Distributed Agents for Autonomy (DAFA) Study has been performed for ESA by SciSys UK Ltd, Vega GmbH and Politecnico di Milano. An analysis of past, present and future space missions has been conducted, structured around a set of three pre-defined mission scenarios: Formation Flying, Earth Observation and Planetary Exploration. This analysis led to the definition of a framework of use cases where the application of distributed autonomy seems necessary or appropriate, and a set of metrics that may be used to assess such deployments. Agent technology and architectures were extensively surveyed and the results used to elaborate each of the mission scenarios to the point where a software prototype could be constructed. Such a prototype was developed for a scenario based on the ExoMars mission and this has been used to highlight the advantages of a DAFA approach to the mission architecture.

  9. Agent based simulations in disease modeling Comment on "Towards a unified approach in the modeling of fibrosis: A review with research perspectives" by Martine Ben Amar and Carlo Bianca

    NASA Astrophysics Data System (ADS)

    Pappalardo, Francesco; Pennisi, Marzio

    2016-07-01

    Fibrosis represents a process where an excessive tissue formation in an organ follows the failure of a physiological reparative or reactive process. Mathematical and computational techniques may be used to improve the understanding of the mechanisms that lead to the disease and to test potential new treatments that may directly or indirectly have positive effects against fibrosis [1]. In this scenario, Ben Amar and Bianca [2] give us a broad picture of the existing mathematical and computational tools that have been used to model fibrotic processes at the molecular, cellular, and tissue levels. Among such techniques, agent based models (ABM) can give a valuable contribution in the understanding and better management of fibrotic diseases.

  10. Rigid bifunctional chelating agents

    DOEpatents

    Sweet, Mark P.; Mease, Ronnie C.; Srivastava, Suresh C.

    1998-07-21

    Bicyclo›2.2.2! octane-2,3 diamine-N,N,N',N'-tetraacetic acids (BODTA) and bicyclo›2.2.1! heptane-2,3 diamine-N,N,N',N'-tetraacetic acid (BHDTA) are chelating agents useful in forming detectably labeled bioconjugate compounds for diagnostic and therapeutic purposes. New compounds and processes of forming BODTA and BHDTA are disclosed. Radioimmunoconjugates of the present invention show high and prolonged tumor uptake with low normal tissue uptakes.

  11. Rigid bifunctional chelating agents

    DOEpatents

    Sweet, Mark P.; Mease, Ronnie C.; Srivastava, Suresh C.

    2000-02-08

    Bicyclo[2.2.2]octane-2,3 diamine-N,N,N',N'-tetraacetic acids (BODTA) and bicyclo[2.2.1]heptane-2,3 diamine-N,N,N',N'-tetraacetic acid (BHDTA) are chelating agents useful in forming detectably labeled bioconjugate compounds for diagnostic and therapeutic purposes. New compounds and processes of forming BODTA and BHDTA are disclosed. Radioimmunoconjugates of the present invention show high and prolonged tumor uptake with low normal tissue uptakes.

  12. Surface polymerization agents

    SciTech Connect

    Taylor, C.; Wilkerson, C.

    1996-12-01

    This is the final report of a 1-year, Laboratory-Directed R&D project at LANL. A joint technical demonstration was proposed between US Army Missile Command (Redstone Arsenal) and LANL. Objective was to demonstrate that an unmanned vehicle or missile could be used as a platform to deliver a surface polymerization agent in such a manner as to obstruct the filters of an air-breathing mechanism, resulting in operational failure.

  13. Rigid bifunctional chelating agents

    DOEpatents

    Sweet, M.P.; Mease, R.C.; Srivastava, S.C.

    1998-07-21

    Bicyclo[2.2.2] octane-2,3 diamine-N,N,N`,N`-tetraacetic acids (BODTA) and bicyclo[2.2.1] heptane-2,3 diamine-N,N,N`,N`-tetraacetic acid (BHDTA) are chelating agents useful in forming detectably labeled bioconjugate compounds for diagnostic and therapeutic purposes. New compounds and processes of forming BODTA and BHDTA are disclosed. Radioimmunoconjugates of the present invention show high and prolonged tumor uptake with low normal tissue uptakes.

  14. Adding ecosystem function to agent-based land use models

    PubMed Central

    Yadav, V.; Del Grosso, S.J.; Parton, W.J.; Malanson, G.P.

    2015-01-01

    The objective of this paper is to examine issues in the inclusion of simulations of ecosystem functions in agent-based models of land use decision-making. The reasons for incorporating these simulations include local interests in land fertility and global interests in carbon sequestration. Biogeochemical models are needed in order to calculate such fluxes. The Century model is described with particular attention to the land use choices that it can encompass. When Century is applied to a land use problem the combinatorial choices lead to a potentially unmanageable number of simulation runs. Century is also parameter-intensive. Three ways of including Century output in agent-based models, ranging from separately calculated look-up tables to agents running Century within the simulation, are presented. The latter may be most efficient, but it moves the computing costs to where they are most problematic. Concern for computing costs should not be a roadblock. PMID:26191077

  15. Perioperative allergy: uncommon agents.

    PubMed

    Caimmi, S; Caimmi, D; Cardinale, F; Indinnimeo, L; Crisafulli, G; Peroni, D G; Marseglia, G L

    2011-01-01

    Anesthesia may often be considered as a high-risk procedure and anaphylaxis remains a major cause of concern for anesthetists who routinely administer many potentially allergenic agents. Neuromuscular blocking agents, latex and antibiotics are the substances involved in most of the reported reactions. Besides these three agents, a wide variety of substances may cause an anaphylactic reaction during anesthesia. Basically all the administered drugs or substances may be potential causes of anaphylaxis. Among them, those reported the most in literature include hypnotics, opioids, local anesthetics, colloids, dye, Non-Steroidal Anti-Inflammatory Drugs (NSAIDs), Iodinated Contrast Media (ICM), antiseptics, aprotinin, ethylene oxyde and formaldehyde, and protamine and heparins. No premedication can effectively prevent an allergic reaction and a systematic preoperative screening is not justified for all patients; nevertheless, an allergy specialist should evaluate those patients with a history of anesthesia-related allergy. Patients must be fully informed of investigation results, and advised to provide a detailed report prior to future anesthesia. PMID:22014927

  16. CATS-based Air Traffic Controller Agents

    NASA Technical Reports Server (NTRS)

    Callantine, Todd J.

    2002-01-01

    This report describes intelligent agents that function as air traffic controllers. Each agent controls traffic in a single sector in real time; agents controlling traffic in adjoining sectors can coordinate to manage an arrival flow across a given meter fix. The purpose of this research is threefold. First, it seeks to study the design of agents for controlling complex systems. In particular, it investigates agent planning and reactive control functionality in a dynamic environment in which a variety perceptual and decision making skills play a central role. It examines how heuristic rules can be applied to model planning and decision making skills, rather than attempting to apply optimization methods. Thus, the research attempts to develop intelligent agents that provide an approximation of human air traffic controller behavior that, while not based on an explicit cognitive model, does produce task performance consistent with the way human air traffic controllers operate. Second, this research sought to extend previous research on using the Crew Activity Tracking System (CATS) as the basis for intelligent agents. The agents use a high-level model of air traffic controller activities to structure the control task. To execute an activity in the CATS model, according to the current task context, the agents reference a 'skill library' and 'control rules' that in turn execute the pattern recognition, planning, and decision-making required to perform the activity. Applying the skills enables the agents to modify their representation of the current control situation (i.e., the 'flick' or 'picture'). The updated representation supports the next activity in a cycle of action that, taken as a whole, simulates air traffic controller behavior. A third, practical motivation for this research is to use intelligent agents to support evaluation of new air traffic control (ATC) methods to support new Air Traffic Management (ATM) concepts. Current approaches that use large, human

  17. Liposome encapsulation of chelating agents

    DOEpatents

    Rahman, Yueh Erh

    1976-01-13

    A method for transferring a chelating agent across a cellular membrane by encapsulating the charged chelating agent within liposomes and carrying the liposome-encapsulated chelating agent to the cellular membrane where the liposomes containing the chelating agent will be taken up by the cells, thereby transferring the chelating agent across the cellular membrane. A chelating agent can be introduced into the interior of a cell of a living organism wherein the liposomes will be decomposed, releasing the chelating agent to the interior of the cell. The released chelating agent will complex intracellularly deposited toxic heavy metals, permitting the more soluble metal complex to transfer across the cellular membrane from the cell and subsequently be removed from the living organism.

  18. Applications of Agent Based Approaches in Business (A Three Essay Dissertation)

    ERIC Educational Resources Information Center

    Prawesh, Shankar

    2013-01-01

    The goal of this dissertation is to investigate the enabling role that agent based simulation plays in business and policy. The aforementioned issue has been addressed in this dissertation through three distinct, but related essays. The first essay is a literature review of different research applications of agent based simulation in various…

  19. Hydroxypyridonate and hydroxypyrimidinone chelating agents

    SciTech Connect

    Raymond, Kenneth N.; Doble, Daniel M.; Sunderland, Christopher J.; Thompson, Marlon

    2005-01-25

    The present invention provides hydroxypyridinone and hydroxypyrimidone chelating agents. Also provides are Gd(III) complexes of these agents, which are useful as contrast enhancing agents for magnetic resonance imaging. The invention also provides methods of preparing the compounds of the invention, as well as methods of using the compounds in magnetic resonance imaging applications.

  20. Collaborating with Autonomous Agents

    NASA Technical Reports Server (NTRS)

    Trujillo, Anna C.; Cross, Charles D.; Fan, Henry; Hempley, Lucas E.; Motter, Mark A.; Neilan, James H.; Qualls, Garry D.; Rothhaar, Paul M.; Tran, Loc D.; Allen, B. Danette

    2015-01-01

    With the anticipated increase of small unmanned aircraft systems (sUAS) entering into the National Airspace System, it is highly likely that vehicle operators will be teaming with fleets of small autonomous vehicles. The small vehicles may consist of sUAS, which are 55 pounds or less that typically will y at altitudes 400 feet and below, and small ground vehicles typically operating in buildings or defined small campuses. Typically, the vehicle operators are not concerned with manual control of the vehicle; instead they are concerned with the overall mission. In order for this vision of high-level mission operators working with fleets of vehicles to come to fruition, many human factors related challenges must be investigated and solved. First, the interface between the human operator and the autonomous agent must be at a level that the operator needs and the agents can understand. This paper details the natural language human factors e orts that NASA Langley's Autonomy Incubator is focusing on. In particular these e orts focus on allowing the operator to interact with the system using speech and gestures rather than a mouse and keyboard. With this ability of the system to understand both speech and gestures, operators not familiar with the vehicle dynamics will be able to easily plan, initiate, and change missions using a language familiar to them rather than having to learn and converse in the vehicle's language. This will foster better teaming between the operator and the autonomous agent which will help lower workload, increase situation awareness, and improve performance of the system as a whole.

  1. Chemical warfare agents.

    PubMed

    Ganesan, K; Raza, S K; Vijayaraghavan, R

    2010-07-01

    Among the Weapons of Mass Destruction, chemical warfare (CW) is probably one of the most brutal created by mankind in comparison with biological and nuclear warfare. Chemical weapons are inexpensive and are relatively easy to produce, even by small terrorist groups, to create mass casualties with small quantities. The characteristics of various CW agents, general information relevant to current physical as well as medical protection methods, detection equipment available and decontamination techniques are discussed in this review article. A brief note on Chemical Weapons Convention is also provided. PMID:21829312

  2. Pharmacologic agents targeting autophagy

    PubMed Central

    Vakifahmetoglu-Norberg, Helin; Xia, Hong-guang; Yuan, Junying

    2015-01-01

    Autophagy is an important intracellular catabolic mechanism critically involved in regulating tissue homeostasis. The implication of autophagy in human diseases and the need to understand its regulatory mechanisms in mammalian cells have stimulated research efforts that led to the development of high-throughput screening protocols and small-molecule modulators that can activate or inhibit autophagy. Herein we review the current landscape in the development of screening technology as well as the molecules and pharmacologic agents targeting the regulatory mechanisms of autophagy. We also evaluate the potential therapeutic application of these compounds in different human pathologies. PMID:25654545

  3. Chemical warfare agents

    PubMed Central

    Ganesan, K.; Raza, S. K.; Vijayaraghavan, R.

    2010-01-01

    Among the Weapons of Mass Destruction, chemical warfare (CW) is probably one of the most brutal created by mankind in comparison with biological and nuclear warfare. Chemical weapons are inexpensive and are relatively easy to produce, even by small terrorist groups, to create mass casualties with small quantities. The characteristics of various CW agents, general information relevant to current physical as well as medical protection methods, detection equipment available and decontamination techniques are discussed in this review article. A brief note on Chemical Weapons Convention is also provided. PMID:21829312

  4. Cleaning agents and asthma.

    PubMed

    Quirce, S; Barranco, P

    2010-01-01

    Although cleaners represent a significant part of the working population worldwide, they remain a relatively understudied occupational group. Epidemiological studies have shown an association between cleaning work and asthma, but the risk factors are uncertain. Cleaning workers are exposed to a large variety of cleaning products containing both irritants and sensitizers, as well as to common indoor allergens and pollutants. Thus, the onset or aggravation of asthma in this group could be related to an irritant-induced mechanism or to specific sensitization. The main sensitizers contained in cleaning products are disinfectants, quaternary ammonium compounds (such as benzalkonium chloride), amine compounds, and fragrances.The strongest airway irritants in cleaning products are bleach (sodium hypochlorite), hydrochloric acid, and alkaline agents (ammonia and sodium hydroxide), which are commonly mixed together. Exposure to the ingredients of cleaning products may give rise to both new-onset asthma, with or without a latency period, and work-exacerbated asthma. High-level exposure to irritants may induce reactive airways dysfunction syndrome. Cleaning workers may also have a greater relative risk of developing asthma due to prolonged low-to-moderate exposure to respiratory irritants. In addition, asthma-like symptoms without confirmed asthma are also common after exposure to cleaning agents. In many cleaners, airway symptoms induced by chemicals and odors cannot be explained by allergic or asthmatic reactions. These patients may have increased sensitivity to inhaled capsaicin, which is known to reflect sensory reactivity, and this condition is termed airway sensory hyperreactivity. PMID:21313993

  5. [New agents for hypercholesterolemia].

    PubMed

    Pintó, Xavier; García Gómez, María Carmen

    2016-02-19

    An elevated proportion of high cardiovascular risk patients do not achieve the therapeutic c-LDL goals. This owes to physicians' inappropriate or insufficient use of cholesterol lowering medications or to patients' bad tolerance or therapeutic compliance. Another cause is an insufficient efficacy of current cholesterol lowering drugs including statins and ezetimibe. In addition, proprotein convertase subtilisin kexin type 9 inhibitors are a new cholesterol lowering medications showing safety and high efficacy to reduce c-LDL in numerous already performed or underway clinical trials, potentially allowing an optimal control of hypercholesterolemia in most patients. Agents inhibiting apolipoprotein B synthesis and microsomal transfer protein are also providing a new potential to decrease cholesterol in patients with severe hypercholesterolemia and in particular in homozygote familial hypercholesterolemia. Last, cholesteryl ester transfer protein inhibitors have shown powerful effects on c-HDL and c-LDL, although their efficacy in cardiovascular prevention and safety has not been demonstrated yet. We provide in this article an overview of the main characteristics of therapeutic agents for hypercholesterolemia, which have been recently approved or in an advanced research stage. PMID:25817449

  6. Holograms as Teaching Agents

    NASA Astrophysics Data System (ADS)

    Walker, Robin A.

    2013-02-01

    Hungarian physicist Dennis Gabor won the Pulitzer Prize for his 1947 introduction of basic holographic principles, but it was not until the invention of the laser in 1960 that research scientists, physicians, technologists and the general public began to seriously consider the interdisciplinary potentiality of holography. Questions around whether and when Three-Dimensional (3-D) images and systems would impact American entertainment and the arts would be answered before educators, instructional designers and students would discover how much Three-Dimensional Hologram Technology (3DHT) would affect teaching practices and learning environments. In the following International Symposium on Display Holograms (ISDH) poster presentation, the author features a traditional board game as well as a reflection hologram to illustrate conventional and evolving Three-Dimensional representations and technology for education. Using elements from the American children's toy Operation® (Hasbro, 2005) as well as a reflection hologram of a human brain (Ko, 1998), this poster design highlights the pedagogical effects of 3-D images, games and systems on learning science. As teaching agents, holograms can be considered substitutes for real objects, (human beings, organs, and animated characters) as well as agents (pedagogical, avatars, reflective) in various learning environments using many systems (direct, emergent, augmented reality) and electronic tools (cellphones, computers, tablets, television). In order to understand the particular importance of utilizing holography in school, clinical and public settings, the author identifies advantages and benefits of using 3-D images and technology as instructional tools.

  7. Synthesized Population Databases: A US Geospatial Database for Agent-Based Models

    PubMed Central

    Wheaton, William D.; Cajka, James C.; Chasteen, Bernadette M.; Wagener, Diane K.; Cooley, Philip C.; Ganapathi, Laxminarayana; Roberts, Douglas J.; Allpress, Justine L.

    2010-01-01

    Agent-based models simulate large-scale social systems. They assign behaviors and activities to “agents” (individuals) within the population being modeled and then allow the agents to interact with the environment and each other in complex simulations. Agent-based models are frequently used to simulate infectious disease outbreaks, among other uses. RTI used and extended an iterative proportional fitting method to generate a synthesized, geospatially explicit, human agent database that represents the US population in the 50 states and the District of Columbia in the year 2000. Each agent is assigned to a household; other agents make up the household occupants. For this database, RTI developed the methods for generating synthesized households and personsassigning agents to schools and workplaces so that complex interactions among agents as they go about their daily activities can be taken into accountgenerating synthesized human agents who occupy group quarters (military bases, college dormitories, prisons, nursing homes).In this report, we describe both the methods used to generate the synthesized population database and the final data structure and data content of the database. This information will provide researchers with the information they need to use the database in developing agent-based models. Portions of the synthesized agent database are available to any user upon request. RTI will extract a portion (a county, region, or state) of the database for users who wish to use this database in their own agent-based models. PMID:20505787

  8. Quantised consensus of multi-agent systems with nonlinear dynamics

    NASA Astrophysics Data System (ADS)

    Zhu, Yunru; Zheng, Yuanshi; Wang, Long

    2015-08-01

    This paper studies the consensus problem of first-order and second-order multi-agent systems with nonlinear dynamics and quantised interactions. Continuous-time and impulsive control inputs are designed for the multi-agent systems on the logarithmic quantised relative state measurements of agents, respectively. By using nonsmooth analysis tools, we get some sufficient conditions for the consensus of multi-agent systems under the continuous-time inputs. Compared with continuous-time control inputs, impulsive distributed control inputs just use the state variables of the systems at discrete-time instances. Based on impulsive control theory, we prove that the multi-agent systems can reach consensus by choosing proper control gains and impulsive intervals. The simulation results are given to verify the effectiveness of the theoretical results.

  9. Adaptation and Learning of Agents in Market Oriented Programming

    NASA Astrophysics Data System (ADS)

    Ishinishi, Masayuki; Namatame, Akira; Kita, Hajime

    Market Oriented Programming (MOP) proposed by Wellman is a decentralized control method using auction machanism inspired by the market economy. It is applied to many problems such as network and computation resource allocation. Conventional MOP models are formulated based on the concept of ‘competitive market’ of economics which assumes that the market consists of sufficiently many and small agents. However, in realistic applications of MOP, number of agents is limited and their interdependency is not negligible. In this paper, MOP for interdependent agents is discussed. An oligopoly market model for MOP is introduced, and adaptation process of interdependent agents and its stability are discussed. Further, it is also demonstrated that selfish learning of adaptation coefficiency by each agent achieves stability of market through computer simulation.

  10. Global optimization of minority game by intelligent agents

    NASA Astrophysics Data System (ADS)

    Xie, Yan-Bo; Wang, Bing-Hong; Hu, Chin-Kun; Zhou, Tao

    2005-10-01

    We propose a new model of minority game with intelligent agents who use trail and error method to make a choice such that the standard deviation σ2 and the total loss in this model reach the theoretical minimum values in the long time limit and the global optimization of the system is reached. This suggests that the economic systems can self-organize into a highly optimized state by agents who make decisions based on inductive thinking, limited knowledge, and capabilities. When other kinds of agents are also present, the simulation results and analytic calculations show that the intelligent agent can gain profits from producers and are much more competent than the noise traders and conventional agents in original minority games proposed by Challet and Zhang.

  11. Agent based modeling of the coevolution of hostility and pacifism

    NASA Astrophysics Data System (ADS)

    Dalmagro, Fermin; Jimenez, Juan

    2015-01-01

    We propose a model based on a population of agents whose states represent either hostile or peaceful behavior. Randomly selected pairs of agents interact according to a variation of the Prisoners Dilemma game, and the probabilities that the agents behave aggressively or not are constantly updated by the model so that the agents that remain in the game are those with the highest fitness. We show that the population of agents oscillate between generalized conflict and global peace, without either reaching a stable state. We then use this model to explain some of the emergent behaviors in collective conflicts, by comparing the simulated results with empirical data obtained from social systems. In particular, using public data reports we show how the model precisely reproduces interesting quantitative characteristics of diverse types of armed conflicts, public protests, riots and strikes.

  12. Synchronised output regulation of nonlinear multi-agent systems

    NASA Astrophysics Data System (ADS)

    Xiang, Ji; Li, Yanjun; Wei, Wei

    2015-01-01

    This paper considers a synchronised output regulation (SOR) problem of nonlinear multi-agent systems with switching graph. The SOR means that all agents have their outputs synchronised but also ultimately evolve on a manifold determined by a predefined exosystem. Each agent constructs its local copy of the predefined exosystem and exchanges the state information of the local exosystem to realise the synchronisation of local exosystem. A controller based on the nonlinear output regulation theory is then presented to force the agent's output track the output of local exosystem. It is shown that the SOR is solvable under the assumptions same as that for nonlinear output regulation of a single agent, if the switching graph satisfies the bounded interconnectivity times condition. Both state feedback and output feedback are addressed. A numerical simulation is made to show the efficacy of the analytic results.

  13. A multiagent architecture for developing medical information retrieval agents.

    PubMed

    Walczak, Steven

    2003-10-01

    Information that is available on the world wide web (WWW) is already more vast than can be comprehensibly studied by individuals and this quantity is increasing at a staggering pace. The quality of service delivered by physicians is dependent on the availability of current information. The agent paradigm offers a means for enabling physicians to filter information and retrieve only information that is relevant to current patient treatments. As with many specialized domains, agent-based information retrieval in medical domains must satisfy several domain-dependent constraints. A multiple agent architecture is developed and described in detail to efficiently provide agent-based information retrieval from the WWW and other explicit information resources. A simulation of the proposed multiple agent architecture shows a 97% decrease in information overload and an 85% increase in information relevancy over existing meta-search tools (with even larger gains over standard search engines). PMID:14584625

  14. Swarming behaviors in multi-agent systems with nonlinear dynamics

    SciTech Connect

    Yu, Wenwu; Chen, Guanrong; Cao, Ming; Lü, Jinhu; Zhang, Hai-Tao

    2013-12-15

    The dynamic analysis of a continuous-time multi-agent swarm model with nonlinear profiles is investigated in this paper. It is shown that, under mild conditions, all agents in a swarm can reach cohesion within a finite time, where the upper bounds of the cohesion are derived in terms of the parameters of the swarm model. The results are then generalized by considering stochastic noise and switching between nonlinear profiles. Furthermore, swarm models with limited sensing range inducing changing communication topologies and unbounded repulsive interactions between agents are studied by switching system and nonsmooth analysis. Here, the sensing range of each agent is limited and the possibility of collision among nearby agents is high. Finally, simulation results are presented to demonstrate the validity of the theoretical analysis.

  15. Learning models of intelligent agents

    SciTech Connect

    Carmel, D.; Markovitch, S.

    1996-12-31

    Agents that operate in a multi-agent system need an efficient strategy to handle their encounters with other agents involved. Searching for an optimal interactive strategy is a hard problem because it depends mostly on the behavior of the others. In this work, interaction among agents is represented as a repeated two-player game, where the agents` objective is to look for a strategy that maximizes their expected sum of rewards in the game. We assume that agents` strategies can be modeled as finite automata. A model-based approach is presented as a possible method for learning an effective interactive strategy. First, we describe how an agent should find an optimal strategy against a given model. Second, we present an unsupervised algorithm that infers a model of the opponent`s automaton from its input/output behavior. A set of experiments that show the potential merit of the algorithm is reported as well.

  16. Flexible, secure agent development framework

    DOEpatents

    Goldsmith; Steven Y.

    2009-04-07

    While an agent generator is generating an intelligent agent, it can also evaluate the data processing platform on which it is executing, in order to assess a risk factor associated with operation of the agent generator on the data processing platform. The agent generator can retrieve from a location external to the data processing platform an open site that is configurable by the user, and load the open site into an agent substrate, thereby creating a development agent with code development capabilities. While an intelligent agent is executing a functional program on a data processing platform, it can also evaluate the data processing platform to assess a risk factor associated with performing the data processing function on the data processing platform.

  17. Flocking of multi-agent systems with multiple groups

    NASA Astrophysics Data System (ADS)

    Jing, Gangshan; Zheng, Yuanshi; Wang, Long

    2014-12-01

    In this paper, we consider the flocking problem of multi-agent systems with multiple groups. First, some algorithms using local information are designed to divide the agents into any pre-assigned number of groups in fixed and switching heterogeneous networks, respectively. Based on algebraic graph theory and Barbalat's lemma, convergence criteria are established to ensure velocity alignment and cohesion of each subgroup as well as collision avoidance between any agents in the whole group. Second, an algorithm for homogeneous networks is studied. Simulation examples are finally presented to verify the effectiveness of our theoretical results.

  18. Bionanoconjugate-based composites for decontamination of nerve agents.

    PubMed

    Borkar, Indrakant V; Dinu, Cerasela Zoica; Zhu, Guangyu; Kane, Ravi S; Dordick, Jonathan S

    2010-01-01

    We have developed enzyme-based composites that rapidly and effectively detoxify simulants of V- and G-type chemical warfare nerve agents. The approach was based on the efficient immobilization of organophosphorus hydrolase onto carbon nanotubes to form active and stable conjugates that were easily entrapped in commercially available paints. The resulting catalytic-based composites showed no enzyme leaching and rendered >99% decontamination of 10 g/m(2) paraoxon, a simulant of the V-type nerve agent, in 30 minutes and >95% decontamination of diisopropylfluorophosphate, a simulant of G-type nerve agent, in 45 minutes. The formulations are expected to be environmentally friendly and to offer an easy to use, on demand, decontamination alternative to chemical approaches for sustainable material self-decontamination. PMID:20859933

  19. Techniques and Issues in Agent-Based Modeling Validation

    SciTech Connect

    Pullum, Laura L; Cui, Xiaohui

    2012-01-01

    Validation of simulation models is extremely important. It ensures that the right model has been built and lends confidence to the use of that model to inform critical decisions. Agent-based models (ABM) have been widely deployed in different fields for studying the collective behavior of large numbers of interacting agents. However, researchers have only recently started to consider the issues of validation. Compared to other simulation models, ABM has many differences in model development, usage and validation. An ABM is inherently easier to build than a classical simulation, but more difficult to describe formally since they are closer to human cognition. Using multi-agent models to study complex systems has attracted criticisms because of the challenges involved in their validation [1]. In this report, we describe the challenge of ABM validation and present a novel approach we recently developed for an ABM system.

  20. New antifungal agents.

    PubMed

    Gupta, Aditya K; Tomas, Elizabeth

    2003-07-01

    Currently, use of standard antifungal therapies can be limited because of toxicity, low efficacy rates, and drug resistance. New formulations are being prepared to improve absorption and efficacy of some of these standard therapies. Various new antifungals have demonstrated therapeutic potential. These new agents may provide additional options for the treatment of superficial fungal infections and they may help to overcome the limitations of current treatments. Liposomal formulations of AmB have a broad spectrum of activity against invasive fungi, such as Candida spp., C. neoformans, and Aspergillus spp., but not dermatophyte fungi. The liposomal AmB is associated with significantly less toxicity and good rates of efficacy, which compare or exceed that of standard AmB. These factors may provide enough of an advantage to patients to overcome the increased costs of these formulations. Three new azole drugs have been developed, and may be of use in both systemic and superficial fungal infections. Voriconazole, ravuconazole, and posaconazole are triazoles, with broad-spectrum activity. Voriconazole has a high bioavailability, and has been used with success in immunocompromised patients with invasive fungal infections. Ravuconazole has shown efficacy in candidiasis in immunocompromised patients, and onychomycosis in healthy patients. Preliminary in vivo studies with posaconazole indicated potential use in a variety of invasive fungal infections including oropharyngeal candidiasis. Echinocandins and pneumocandins are a new class of antifungals, which act as fungal cell wall beta-(1,3)-D-glucan synthase enzyme complex inhibitors. Caspofungin (MK-0991) is the first of the echinocandins to receive Food and Drug Administration approval for patients with invasive aspergillosis not responding or intolerant to other antifungal therapies, and has been effective in patients with oropharyngeal and esophageal candidiasis. Standardization of MIC value determination has improved the

  1. Fluoroquinolone antimicrobial agents.

    PubMed Central

    Wolfson, J S; Hooper, D C

    1989-01-01

    The fluoroquinolones, a new class of potent orally absorbed antimicrobial agents, are reviewed, considering structure, mechanisms of action and resistance, spectrum, variables affecting activity in vitro, pharmacokinetic properties, clinical efficacy, emergence of resistance, and tolerability. The primary bacterial target is the enzyme deoxyribonucleic acid gyrase. Bacterial resistance occurs by chromosomal mutations altering deoxyribonucleic acid gyrase and decreasing drug permeation. The drugs are bactericidal and potent in vitro against members of the family Enterobacteriaceae, Haemophilus spp., and Neisseria spp., have good activity against Pseudomonas aeruginosa and staphylococci, and (with several exceptions) are less potent against streptococci and have fair to poor activity against anaerobic species. Potency in vitro decreases in the presence of low pH, magnesium ions, or urine but is little affected by different media, increased inoculum, or serum. The effects of the drugs in combination with a beta-lactam or aminoglycoside are often additive, occasionally synergistic, and rarely antagonistic. The agents are orally absorbed, require at most twice-daily dosing, and achieve high concentrations in urine, feces, and kidney and good concentrations in lung, bone, prostate, and other tissues. The drugs are efficacious in treatment of a variety of bacterial infections, including uncomplicated and complicated urinary tract infections, bacterial gastroenteritis, and gonorrhea, and show promise for therapy of prostatitis, respiratory tract infections, osteomyelitis, and cutaneous infections, particularly when caused by aerobic gram-negative bacilli. Fluoroquinolones have also proved to be efficacious for prophylaxis against travelers' diarrhea and infection with gram-negative bacilli in neutropenic patients. The drugs are effective in eliminating carriage of Neisseria meningitidis. Patient tolerability appears acceptable, with gastrointestinal or central nervous

  2. A novel alignment repulsion algorithm for flocking of multi-agent systems based on the number of neighbours per agent

    NASA Astrophysics Data System (ADS)

    Kahani, R.; Sedigh, A. K.; Mahjani, M. Gh.

    2015-12-01

    In this paper, an energy-based control methodology is proposed to satisfy the Reynolds three rules in a flock of multiple agents. First, a control law is provided that is directly derived from the passivity theorem. In the next step, the Number of Neighbours Alignment/Repulsion algorithm is introduced for a flock of agents which loses the cohesion ability and uniformly joint connectivity condition. With this method, each agent tries to follow the agents which escape its neighbourhood by considering the velocity of escape time and number of neighbours. It is mathematically proved that the motion of multiple agents converges to a rigid and uncrowded flock if the group is jointly connected just for an instant. Moreover, the conditions for collision avoidance are guaranteed during the entire process. Finally, simulation results are presented to show the effectiveness of the proposed methodology.

  3. Projective simulation for artificial intelligence

    PubMed Central

    Briegel, Hans J.; De las Cuevas, Gemma

    2012-01-01

    We propose a model of a learning agent whose interaction with the environment is governed by a simulation-based projection, which allows the agent to project itself into future situations before it takes real action. Projective simulation is based on a random walk through a network of clips, which are elementary patches of episodic memory. The network of clips changes dynamically, both due to new perceptual input and due to certain compositional principles of the simulation process. During simulation, the clips are screened for specific features which trigger factual action of the agent. The scheme is different from other, computational, notions of simulation, and it provides a new element in an embodied cognitive science approach to intelligent action and learning. Our model provides a natural route for generalization to quantum-mechanical operation and connects the fields of reinforcement learning and quantum computation. PMID:22590690

  4. Projective simulation for artificial intelligence.

    PubMed

    Briegel, Hans J; De las Cuevas, Gemma

    2012-01-01

    We propose a model of a learning agent whose interaction with the environment is governed by a simulation-based projection, which allows the agent to project itself into future situations before it takes real action. Projective simulation is based on a random walk through a network of clips, which are elementary patches of episodic memory. The network of clips changes dynamically, both due to new perceptual input and due to certain compositional principles of the simulation process. During simulation, the clips are screened for specific features which trigger factual action of the agent. The scheme is different from other, computational, notions of simulation, and it provides a new element in an embodied cognitive science approach to intelligent action and learning. Our model provides a natural route for generalization to quantum-mechanical operation and connects the fields of reinforcement learning and quantum computation. PMID:22590690

  5. Projective simulation for artificial intelligence

    NASA Astrophysics Data System (ADS)

    Briegel, Hans J.; de Las Cuevas, Gemma

    2012-05-01

    We propose a model of a learning agent whose interaction with the environment is governed by a simulation-based projection, which allows the agent to project itself into future situations before it takes real action. Projective simulation is based on a random walk through a network of clips, which are elementary patches of episodic memory. The network of clips changes dynamically, both due to new perceptual input and due to certain compositional principles of the simulation process. During simulation, the clips are screened for specific features which trigger factual action of the agent. The scheme is different from other, computational, notions of simulation, and it provides a new element in an embodied cognitive science approach to intelligent action and learning. Our model provides a natural route for generalization to quantum-mechanical operation and connects the fields of reinforcement learning and quantum computation.

  6. Kinetics of pulpal temperature rise during light curing of 6 bonding agents from different generations, using light emitting diode and quartz-tungsten-halogen units: An in-vitro simulation

    PubMed Central

    Khaksaran, Najmeh Khatoon; Kashi, Tahereh Jafarzadeh; Rakhshan, Vahid; Zeynolabedin, Zahra Sadat; Bagheri, Hossein

    2015-01-01

    Background: Application of bonding agents (BA) into deep cavities and light curing them might increase pulpal temperature and threaten its health. The purpose of this study was to evaluate temperature rise of pulp by light curing six BA using two different light curing units (LCU), through a dent in wall of 0.5 mm. Materials and Methods: This in vitro experiment was carried out on 96 slices of the same number of human third molars (6 BAs × 2 LCUs × 8 specimens in each group). There were 6 groups of BAs: N Bond, G-Bond, OptiBond XTR, Clearfil SE, Adper Single Bond 2 and V Bond. Each group of BA (n = 16) had two subgroups of light emitting diode (LED) and quartz-tungsten-halogen light cure units (n = 8). Each of these 16 specimens were subjected to light emitting for 20 s, once without any BAs (control) and later when a BA was applied to surface of disk. Temperature rises in 140 s were evaluated. Their mean temperature change in first 20 s were calculated and analyzed using two-way repeated-measures and one-way analysis of variance (ANOVA) and Tukey (α = 0.05). Furthermore rate of temperature increase was calculated for each material and LCU. Results: Minimum and maximum temperature rises in all subgroups were 1.7 and 2.8°C, respectively. Repeated measures ANOVA showed that both of adhesive and LCU types had significant effect on temperature rise after application of adhesives. Tukey post-hoc analysis showed Clearfil SE showed significantly higher temperature rise in comparison with Adper Single bond 2 (P = 0.047) and N Bond (P = 0.038). Temperature rose in a linear fashion during first 30-40 s and after that it was non-linear. Conclusion: 20 s of light curing seems safe for pulpal health (with critical threshold of 5.5°C). However, in longer durations and especially when using LED units, the process should be broken to two sessions. PMID:25878684

  7. Hepatocytes as Immunological Agents.

    PubMed

    Crispe, Ian N

    2016-01-01

    Hepatocytes are targeted for infection by a number of major human pathogens, including hepatitis B virus, hepatitis C virus, and malaria. However, hepatocytes are also immunological agents in their own right. In systemic immunity, they are central in the acute-phase response, which floods the circulation with defensive proteins during diverse stresses, including ischemia, physical trauma, and sepsis. Hepatocytes express a variety of innate immune receptors and, when challenged with pathogen- or damage-associated molecular patterns, can deliver cell-autonomous innate immune responses that may result in host defense or in immunopathology. Important human pathogens have evolved mechanisms to subvert these responses. Finally, hepatocytes talk directly to T cells, resulting in a bias toward immune tolerance. PMID:26685314

  8. Agent Assignment for Process Management: Pattern Based Agent Performance Evaluation

    NASA Astrophysics Data System (ADS)

    Jablonski, Stefan; Talib, Ramzan

    In almost all workflow management system the role concept is determined once at the introduction of workflow application and is not reevaluated to observe how successfully certain processes are performed by the authorized agents. This paper describes an approach which evaluates how agents are working successfully and feed this information back for future agent assignment to achieve maximum business benefit for the enterprise. The approach is called Pattern based Agent Performance Evaluation (PAPE) and is based on machine learning technique combined with post processing technique. We report on the result of our experiments and discuss issues and improvement of our approach.

  9. Successful technical trading agents using genetic programming.

    SciTech Connect

    Othling, Andrew S.; Kelly, John A.; Pryor, Richard J.; Farnsworth, Grant V.

    2004-10-01

    Genetic programming (GP) has proved to be a highly versatile and useful tool for identifying relationships in data for which a more precise theoretical construct is unavailable. In this project, we use a GP search to develop trading strategies for agent based economic models. These strategies use stock prices and technical indicators, such as the moving average convergence/divergence and various exponentially weighted moving averages, to generate buy and sell signals. We analyze the effect of complexity constraints on the strategies as well as the relative performance of various indicators. We also present innovations in the classical genetic programming algorithm that appear to improve convergence for this problem. Technical strategies developed by our GP algorithm can be used to control the behavior of agents in economic simulation packages, such as ASPEN-D, adding variety to the current market fundamentals approach. The exploitation of arbitrage opportunities by technical analysts may help increase the efficiency of the simulated stock market, as it does in the real world. By improving the behavior of simulated stock markets, we can better estimate the effects of shocks to the economy due to terrorism or natural disasters.

  10. Exploration for Agents with Different Personalities in Unknown Environments

    NASA Astrophysics Data System (ADS)

    Doumit, Sarjoun; Minai, Ali

    We present in this paper a personality-based architecture (PA) that combines elements from the subsumption architecture and reinforcement learning to find alternate solutions for problems facing artificial agents exploring unknown environments. The underlying PA algorithm is decomposed into layers according to the different (non-contiguous) stages that our agent passes in, which in turn are influenced by the sources of rewards present in the environment. The cumulative rewards collected by an agent, in addition to its internal composition serve as factors in shaping its personality. In missions where multiple agents are deployed, our solution-goal is to allow each of the agents develop its own distinct personality in order for the collective to reach a balanced society, which then can accumulate the largest possible amount of rewards for the agent and society as well. The architecture is tested in a simulated matrix world which embodies different types of positive rewards and negative rewards. Varying experiments are performed to compare the performance of our algorithm with other algorithms under the same environment conditions. The use of our architecture accelerates the overall adaptation of the agents to their environment and goals by allowing the emergence of an optimal society of agents with different personalities. We believe that our approach achieves much efficient results when compared to other more restrictive policy designs.

  11. Agent-based enterprise integration

    SciTech Connect

    N. M. Berry; C. M. Pancerella

    1998-12-01

    The authors are developing and deploying software agents in an enterprise information architecture such that the agents manage enterprise resources and facilitate user interaction with these resources. The enterprise agents are built on top of a robust software architecture for data exchange and tool integration across heterogeneous hardware and software. The resulting distributed multi-agent system serves as a method of enhancing enterprises in the following ways: providing users with knowledge about enterprise resources and applications; accessing the dynamically changing enterprise; locating enterprise applications and services; and improving search capabilities for applications and data. Furthermore, agents can access non-agents (i.e., databases and tools) through the enterprise framework. The ultimate target of the effort is the user; they are attempting to increase user productivity in the enterprise. This paper describes their design and early implementation and discusses the planned future work.

  12. Collaborating Fuzzy Reinforcement Learning Agents

    NASA Technical Reports Server (NTRS)

    Berenji, Hamid R.

    1997-01-01

    Earlier, we introduced GARIC-Q, a new method for doing incremental Dynamic Programming using a society of intelligent agents which are controlled at the top level by Fuzzy Relearning and at the local level, each agent learns and operates based on ANTARCTIC, a technique for fuzzy reinforcement learning. In this paper, we show that it is possible for these agents to compete in order to affect the selected control policy but at the same time, they can collaborate while investigating the state space. In this model, the evaluator or the critic learns by observing all the agents behaviors but the control policy changes only based on the behavior of the winning agent also known as the super agent.

  13. New agents for prostate cancer.

    PubMed

    Agarwal, N; Di Lorenzo, G; Sonpavde, G; Bellmunt, J

    2014-09-01

    The therapeutic landscape of metastatic castration-resistant prostate cancer (mCRPC) has been revolutionized by the arrival of multiple novel agents in the past 2 years. Immunotherapy in the form of sipuleucel-T, androgen axis inhibitors, including abiraterone acetate and enzalutamide, a chemotherapeutic agent, cabazitaxel, and a radiopharmaceutical, radium-223, have all yielded incremental extensions of survival and have been recently approved. A number of other agents appear promising in early studies, suggesting that the armamentarium against castrate-resistant prostate cancer is likely to continue to expand. Emerging androgen pathway inhibitors include androgen synthesis inhibitors (TAK700), androgen receptor inhibitors (ARN-509, ODM-201), AR DNA binding domain inhibitors (EPI-001), selective AR downregulators or SARDs (AZD-3514), and agents that inhibit both androgen synthesis and receptor binding (TOK-001/galeterone). Promising immunotherapeutic agents include poxvirus vaccines and CTLA-4 inhibitor (ipilimumab). Biologic agents targeting the molecular drivers of disease are also being investigated as single agents, including cabozantinib (Met and VEGFR2 inhibitor) and tasquinimod (angiogenesis and immune modulatory agent). Despite the disappointing results seen from studies evaluating docetaxel in combination with other agents, including GVAX, anti-angiogentic agents (bevacizumab, aflibercept, lenalinomide), a SRC kinase inhibitor (dasatinib), endothelin receptor antagonists (atrasentan, zibotentan), and high-dose calcitriol (DN-101), the results from the trial evaluating docetaxel in combination with the clusterin antagonist, custirsen, are eagerly awaited. New therapeutic hurdles consist of discovering new targets, understanding resistance mechanisms, the optimal sequencing and combinations of available agents, as well as biomarkers predictive for benefit. Novel agents targeting bone metastases are being developed following the success of zoledronic acid

  14. High performance computing for three-dimensional agent-based molecular models.

    PubMed

    Pérez-Rodríguez, G; Pérez-Pérez, M; Fdez-Riverola, F; Lourenço, A

    2016-07-01

    Agent-based simulations are increasingly popular in exploring and understanding cellular systems, but the natural complexity of these systems and the desire to grasp different modelling levels demand cost-effective simulation strategies and tools. In this context, the present paper introduces novel sequential and distributed approaches for the three-dimensional agent-based simulation of individual molecules in cellular events. These approaches are able to describe the dimensions and position of the molecules with high accuracy and thus, study the critical effect of spatial distribution on cellular events. Moreover, two of the approaches allow multi-thread high performance simulations, distributing the three-dimensional model in a platform independent and computationally efficient way. Evaluation addressed the reproduction of molecular scenarios and different scalability aspects of agent creation and agent interaction. The three approaches simulate common biophysical and biochemical laws faithfully. The distributed approaches show improved performance when dealing with large agent populations while the sequential approach is better suited for small to medium size agent populations. Overall, the main new contribution of the approaches is the ability to simulate three-dimensional agent-based models at the molecular level with reduced implementation effort and moderate-level computational capacity. Since these approaches have a generic design, they have the major potential of being used in any event-driven agent-based tool. PMID:27372059

  15. Broad-spectrum antiviral agents

    PubMed Central

    Zhu, Jun-Da; Meng, Wen; Wang, Xiao-Jia; Wang, Hwa-Chain R.

    2015-01-01

    Development of highly effective, broad-spectrum antiviral agents is the major objective shared by the fields of virology and pharmaceutics. Antiviral drug development has focused on targeting viral entry and replication, as well as modulating cellular defense system. High throughput screening of molecules, genetic engineering of peptides, and functional screening of agents have identified promising candidates for development of optimal broad-spectrum antiviral agents to intervene in viral infection and control viral epidemics. This review discusses current knowledge, prospective applications, opportunities, and challenges in the development of broad-spectrum antiviral agents. PMID:26052325

  16. Learning in engineered multi-agent systems

    NASA Astrophysics Data System (ADS)

    Menon, Anup

    graph (communication graph) and, under certain conditions, prove convergence of agent joint action (under eITEL) to the welfare optimizing set. The main condition requires that the union of interaction and communication graphs be strongly connected; thus the algorithm combines an implicit form of communication (via interactions through utility functions) with explicit inter-agent communications to achieve the given collaborative goal. This work has kinship with certain evolutionary computation techniques such as Simulated Annealing; the algorithm steps are carefully designed such that it describes an ergodic Markov chain with a stationary distribution that has support over states where agent joint actions optimize the welfare function. The main analysis tool is perturbed Markov chains and results of broader interest regarding these are derived as well. The other algorithm, Collaborative Extremum Seeking (CES), uses techniques from extremum seeking control to solve the problem when agent actions are drawn from the set of real numbers. In this case, under the assumption of existence of a local minimizer for the welfare function and a connected undirected communication graph between agents, a result regarding convergence of joint action to a small neighborhood of a local optimizer of the welfare function is proved. Since extremum seeking control uses a simultaneous gradient estimation-descent scheme, gradient information available in the continuous action space formulation is exploited by the CES algorithm to yield improved convergence speeds. The effectiveness of this algorithm for the wind farm power maximization problem is evaluated via simulations. Lastly, we turn to a different question regarding role of the information exchange pattern on performance of distributed control systems by means of a case study for the vehicle platooning problem. In the vehicle platoon control problem, the objective is to design distributed control laws for individual vehicles in a platoon

  17. The Agent of Change: The Agent of Conflict.

    ERIC Educational Resources Information Center

    Hatfield, C. R., Jr.

    This speech examines the role of change agents in third world societies and indicates that the change agent must, to some extent, manipulate the social situation, even if his view of society is a more optimistic one than he finds in reality. If he considers strains and stresses to be the lubricants of change, then his focus on conflict as a…

  18. Incorporating BDI Agents into Human-Agent Decision Making Research

    NASA Astrophysics Data System (ADS)

    Kamphorst, Bart; van Wissen, Arlette; Dignum, Virginia

    Artificial agents, people, institutes and societies all have the ability to make decisions. Decision making as a research area therefore involves a broad spectrum of sciences, ranging from Artificial Intelligence to economics to psychology. The Colored Trails (CT) framework is designed to aid researchers in all fields in examining decision making processes. It is developed both to study interaction between multiple actors (humans or software agents) in a dynamic environment, and to study and model the decision making of these actors. However, agents in the current implementation of CT lack the explanatory power to help understand the reasoning processes involved in decision making. The BDI paradigm that has been proposed in the agent research area to describe rational agents, enables the specification of agents that reason in abstract concepts such as beliefs, goals, plans and events. In this paper, we present CTAPL: an extension to CT that allows BDI software agents that are written in the practical agent programming language 2APL to reason about and interact with a CT environment.

  19. Plasmids encoding therapeutic agents

    DOEpatents

    Keener, William K.

    2007-08-07

    Plasmids encoding anti-HIV and anti-anthrax therapeutic agents are disclosed. Plasmid pWKK-500 encodes a fusion protein containing DP178 as a targeting moiety, the ricin A chain, an HIV protease cleavable linker, and a truncated ricin B chain. N-terminal extensions of the fusion protein include the maltose binding protein and a Factor Xa protease site. C-terminal extensions include a hydrophobic linker, an L domain motif peptide, a KDEL ER retention signal, another Factor Xa protease site, an out-of-frame buforin II coding sequence, the lacZ.alpha. peptide, and a polyhistidine tag. More than twenty derivatives of plasmid pWKK-500 are described. Plasmids pWKK-700 and pWKK-800 are similar to pWKK-500 wherein the DP178-encoding sequence is substituted by RANTES- and SDF-1-encoding sequences, respectively. Plasmid pWKK-900 is similar to pWKK-500 wherein the HIV protease cleavable linker is substituted by a lethal factor (LF) peptide-cleavable linker.

  20. TACtic- A Multi Behavioral Agent for Trading Agent Competition

    NASA Astrophysics Data System (ADS)

    Khosravi, Hassan; Shiri, Mohammad E.; Khosravi, Hamid; Iranmanesh, Ehsan; Davoodi, Alireza

    Software agents are increasingly being used to represent humans in online auctions. Such agents have the advantages of being able to systematically monitor a wide variety of auctions and then make rapid decisions about what bids to place in what auctions. They can do this continuously and repetitively without losing concentration. To provide a means of evaluating and comparing (benchmarking) research methods in this area the trading agent competition (TAC) was established. This paper describes the design, of TACtic. Our agent uses multi behavioral techniques at the heart of its decision making to make bidding decisions in the face of uncertainty, to make predictions about the likely outcomes of auctions, and to alter the agent's bidding strategy in response to the prevailing market conditions.