Science.gov

Sample records for conceptual site model

  1. Uncertainty and the Conceptual Site Model

    NASA Astrophysics Data System (ADS)

    Price, V.; Nicholson, T. J.

    2007-12-01

    Our focus is on uncertainties in the underlying conceptual framework upon which all subsequent steps in numerical and/or analytical modeling efforts depend. Experienced environmental modelers recognize the value of selecting an optimal conceptual model from several competing site models, but usually do not formally explore possible alternative models, in part due to incomplete or missing site data, as well as relevant regional data for establishing boundary conditions. The value in and approach for developing alternative conceptual site models (CSM) is demonstrated by analysis of case histories. These studies are based on reported flow or transport modeling in which alternative site models are formulated using data that were not available to, or not used by, the original modelers. An important concept inherent to model abstraction of these alternative conceptual models is that it is "Far better an approximate answer to the right question, which is often vague, than the exact answer to the wrong question, which can always be made precise." (Tukey, 1962) The case histories discussed here illustrate the value of formulating alternative models and evaluating them using site-specific data: (1) Charleston Naval Site where seismic characterization data allowed significant revision of the CSM and subsequent contaminant transport modeling; (2) Hanford 300-Area where surface- and ground-water interactions affecting the unsaturated zone suggested an alternative component to the site model; (3) Savannah River C-Area where a characterization report for a waste site within the modeled area was not available to the modelers, but provided significant new information requiring changes to the underlying geologic and hydrogeologic CSM's used; (4) Amargosa Desert Research Site (ADRS) where re-interpretation of resistivity sounding data and water-level data suggested an alternative geologic model. Simple 2-D spreadsheet modeling of the ADRS with the revised CSM provided an improved

  2. Evaluating Conceptual Site Models with Multicomponent Reactive Transport Modeling

    NASA Astrophysics Data System (ADS)

    Dai, Z.; Heffner, D.; Price, V.; Temples, T. J.; Nicholson, T. J.

    2005-05-01

    Modeling ground-water flow and multicomponent reactive chemical transport is a useful approach for testing conceptual site models and assessing the design of monitoring networks. A graded approach with three conceptual site models is presented here with a field case of tetrachloroethene (PCE) transport and biodegradation near Charleston, SC. The first model assumed a one-layer homogeneous aquifer structure with semi-infinite boundary conditions, in which an analytical solution of the reactive solute transport can be obtained with BIOCHLOR (Aziz et al., 1999). Due to the over-simplification of the aquifer structure, this simulation cannot reproduce the monitoring data. In the second approach we used GMS to develop the conceptual site model, a layer-cake multi-aquifer system, and applied a numerical module (MODFLOW and RT3D within GMS) to solve the flow and reactive transport problem. The results were better than the first approach but still did not fit the plume well because the geological structures were still inadequately defined. In the third approach we developed a complex conceptual site model by interpreting log and seismic survey data with Petra and PetraSeis. We detected a major channel and a younger channel, through the PCE source area. These channels control the local ground-water flow direction and provide a preferential chemical transport pathway. Results using the third conceptual site model agree well with the monitoring concentration data. This study confirms that the bias and uncertainty from inadequate conceptual models are much larger than those introduced from an inadequate choice of model parameter values (Neuman and Wierenga, 2003; Meyer et al., 2004). Numerical modeling in this case provides key insight into the hydrogeology and geochemistry of the field site for predicting contaminant transport in the future. Finally, critical monitoring points and performance indicator parameters are selected for future monitoring to confirm system

  3. Karstification beneath dam sites: From conceptual models to realistic scenarios

    NASA Astrophysics Data System (ADS)

    Hiller, Thomas; Kaufmann, Georg; Romanov, Douchko

    2010-05-01

    Dam sites located above soluble rock such as limestone or gypsum can leak in relatively short times (tenths of years), when compared to the natural time scale of karstification (10.000-100.000 years). The reason for this leakage is the high hydraulic gradient imposed by the reservoir that drives aggressive water through the fracture and fissure system of the bedrock and this aggressive water dissolves the rock and increases permeability fairly fast. Thus, on the one hand water losses through enlarged fractures can become a problem for the reservoir. On the other hand, the void space itself can be a risk for the dam structure above. This may have unpredictable ecological and economical consequences. We present a three-dimensional conceptual model study of karstification in dam-site areas on limestone bedrock. We compare our three-dimensional model to a standard two-dimensional dam site model to verify the results of our code. We further carry out a sensitivity analysis on the physical and chemical parameters driving the karstification to derive an empirical formulation of the breakthrough time TB. In a next step we implement a statistical fracture network and topography to approach a more realistic scenario. Finally we show the results of a three dimensional model based on a real dam site.

  4. Using the conceptual site model approach to characterize groundwater quality

    SciTech Connect

    Shephard, E.; Glucksberg, N.; Walter, N.

    2007-07-01

    To understand groundwater quality, the first step is to develop a conceptual site model (CSM) that describes the site history, describes the geology and the hydrogeology of the site, identifies potential release areas or sources, and evaluates the fate and transport of site related compounds. After the physical site setting is understood and potential release areas are identified, appropriate and representative groundwater monitoring wells may be used to evaluate groundwater quality at a site and provide a network to assess impacts from potential future releases. To develop the CSM, the first step to understand the different requirements from each of the regulatory stakeholders. Each regulatory agency may have different approaches to site characterization and closure (i.e., different groundwater and soil remediation criteria). For example, the United States Environmental Protection Agency (EPA) and state governments have published guidance documents that proscribe the required steps and information needed to develop a CSM. The Nuclear Regulatory Commission (NRC) has a proscriptive model for the Historical Site Assessment under the Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM), and contains requirements for developing a conceptual site model in NUREG 1757. Federal and state agencies may also have different closure criteria for potential contaminants of concern. Understanding these differences before starting a groundwater monitoring program is important because the minimum detectable activity (MDA), lowest limit detection (LLD), and sample quantitation limit (SQL) must be low enough so that data may be evaluated under each of the programs. After a Historical Site Assessment is completed a work plan is developed and executed to not only collect physical data that describes the geology and hydrogeology, but to also characterize the soil, groundwater, sediments, and surface water quality of each potentially impacted areas. Although the primary

  5. A Bayesian belief network approach for assessing uncertainty in conceptual site models at contaminated sites

    NASA Astrophysics Data System (ADS)

    Thomsen, Nanna I.; Binning, Philip J.; McKnight, Ursula S.; Tuxen, Nina; Bjerg, Poul L.; Troldborg, Mads

    2016-05-01

    A key component in risk assessment of contaminated sites is in the formulation of a conceptual site model (CSM). A CSM is a simplified representation of reality and forms the basis for the mathematical modeling of contaminant fate and transport at the site. The CSM should therefore identify the most important site-specific features and processes that may affect the contaminant transport behavior at the site. However, the development of a CSM will always be associated with uncertainties due to limited data and lack of understanding of the site conditions. CSM uncertainty is often found to be a major source of model error and it should therefore be accounted for when evaluating uncertainties in risk assessments. We present a Bayesian belief network (BBN) approach for constructing CSMs and assessing their uncertainty at contaminated sites. BBNs are graphical probabilistic models that are effective for integrating quantitative and qualitative information, and thus can strengthen decisions when empirical data are lacking. The proposed BBN approach facilitates a systematic construction of multiple CSMs, and then determines the belief in each CSM using a variety of data types and/or expert opinion at different knowledge levels. The developed BBNs combine data from desktop studies and initial site investigations with expert opinion to assess which of the CSMs are more likely to reflect the actual site conditions. The method is demonstrated on a Danish field site, contaminated with chlorinated ethenes. Four different CSMs are developed by combining two contaminant source zone interpretations (presence or absence of a separate phase contamination) and two geological interpretations (fractured or unfractured clay till). The beliefs in each of the CSMs are assessed sequentially based on data from three investigation stages (a screening investigation, a more detailed investigation, and an expert consultation) to demonstrate that the belief can be updated as more information

  6. A Bayesian belief network approach for assessing uncertainty in conceptual site models at contaminated sites.

    PubMed

    Thomsen, Nanna I; Binning, Philip J; McKnight, Ursula S; Tuxen, Nina; Bjerg, Poul L; Troldborg, Mads

    2016-05-01

    A key component in risk assessment of contaminated sites is in the formulation of a conceptual site model (CSM). A CSM is a simplified representation of reality and forms the basis for the mathematical modeling of contaminant fate and transport at the site. The CSM should therefore identify the most important site-specific features and processes that may affect the contaminant transport behavior at the site. However, the development of a CSM will always be associated with uncertainties due to limited data and lack of understanding of the site conditions. CSM uncertainty is often found to be a major source of model error and it should therefore be accounted for when evaluating uncertainties in risk assessments. We present a Bayesian belief network (BBN) approach for constructing CSMs and assessing their uncertainty at contaminated sites. BBNs are graphical probabilistic models that are effective for integrating quantitative and qualitative information, and thus can strengthen decisions when empirical data are lacking. The proposed BBN approach facilitates a systematic construction of multiple CSMs, and then determines the belief in each CSM using a variety of data types and/or expert opinion at different knowledge levels. The developed BBNs combine data from desktop studies and initial site investigations with expert opinion to assess which of the CSMs are more likely to reflect the actual site conditions. The method is demonstrated on a Danish field site, contaminated with chlorinated ethenes. Four different CSMs are developed by combining two contaminant source zone interpretations (presence or absence of a separate phase contamination) and two geological interpretations (fractured or unfractured clay till). The beliefs in each of the CSMs are assessed sequentially based on data from three investigation stages (a screening investigation, a more detailed investigation, and an expert consultation) to demonstrate that the belief can be updated as more information

  7. SITE CHARACTERIZATION TO SUPPORT DEVELOPMENT OF CONCEPTUAL SITE MODELS AND TRANSPORT MODELS FOR MONITORING CONTAMINANTS IN GROUND WATER

    EPA Science Inventory

    The development of conceptual and predictive models is an important tool to guide site characterization in support of monitoring contaminants in ground water. The accuracy of predictive models is limited by the adequacy of the input data and the assumptions made to constrain mod...

  8. Refining the site conceptual model at a former uranium mill site in Riverton, Wyoming, USA

    DOE PAGESBeta

    Dam, William; Campbell, Sam; Johnson, Ray; Looney, Brian; Denham, Miles E.; Eddy-Dilek, Carol A.; Babits, Steven J.

    2015-07-07

    Milling activities at a former uranium mill site near Riverton, Wyoming, USA, contaminated the shallow groundwater beneath and downgradient of the site. Although the mill operated for <6 years (1958-1963), its impact remains an environmental liability. Groundwater modeling predicted that contaminant concentrations were declining steadily, which confirmed the conceptual site model (CSM). However, local flooding in 2010 mobilized contaminants that migrated downgradient from the Riverton site and resulted in a dramatic increase in groundwater contaminant concentrations. This observation indicated that the original CSM was inadequate to explain site conditions and needed to be refined. In response to the new observationsmore » after the flood, a collaborative investigation to better understand site conditions and processes commenced. This investigation included installing 103 boreholes to collect soil and groundwater samples, sampling and analysis of evaporite minerals along the bank of the Little Wind River, an analysis of evaportranspiration in the shallow aquifer, and sampling naturally organic-rich sediments near groundwater discharge areas. The enhanced characterization revealed that the existing CSM did not account for high uranium concentrations in groundwater remaining on the former mill site and groundwater plume stagnation near the Little Wind River. Observations from the flood and subsequent investigations indicate that additional characterization is still needed to continue refining the CSM and determine the viability of the natural flushing compliance strategy. Additional sampling, analysis, and testing of soil and groundwater are necessary to investigate secondary contaminant sources, mobilization of contaminants during floods, geochemical processes, contaminant plume stagnation, distribution of evaporite minerals and organic-rich sediments, and mechanisms and rates of contaminant transfer from soil to groundwater. Future data collection will be used to

  9. Refining the site conceptual model at a former uranium mill site in Riverton, Wyoming, USA

    SciTech Connect

    Dam, William; Campbell, Sam; Johnson, Ray; Looney, Brian; Denham, Miles E.; Eddy-Dilek, Carol A.; Babits, Steven J.

    2015-07-07

    Milling activities at a former uranium mill site near Riverton, Wyoming, USA, contaminated the shallow groundwater beneath and downgradient of the site. Although the mill operated for <6 years (1958-1963), its impact remains an environmental liability. Groundwater modeling predicted that contaminant concentrations were declining steadily, which confirmed the conceptual site model (CSM). However, local flooding in 2010 mobilized contaminants that migrated downgradient from the Riverton site and resulted in a dramatic increase in groundwater contaminant concentrations. This observation indicated that the original CSM was inadequate to explain site conditions and needed to be refined. In response to the new observations after the flood, a collaborative investigation to better understand site conditions and processes commenced. This investigation included installing 103 boreholes to collect soil and groundwater samples, sampling and analysis of evaporite minerals along the bank of the Little Wind River, an analysis of evaportranspiration in the shallow aquifer, and sampling naturally organic-rich sediments near groundwater discharge areas. The enhanced characterization revealed that the existing CSM did not account for high uranium concentrations in groundwater remaining on the former mill site and groundwater plume stagnation near the Little Wind River. Observations from the flood and subsequent investigations indicate that additional characterization is still needed to continue refining the CSM and determine the viability of the natural flushing compliance strategy. Additional sampling, analysis, and testing of soil and groundwater are necessary to investigate secondary contaminant sources, mobilization of contaminants during floods, geochemical processes, contaminant plume stagnation, distribution of evaporite minerals and organic-rich sediments, and mechanisms and rates of contaminant transfer from soil to groundwater. Future data collection will be used to

  10. Mass discharge estimation from contaminated sites: Multi-model solutions for assessment of conceptual uncertainty

    NASA Astrophysics Data System (ADS)

    Thomsen, N. I.; Troldborg, M.; McKnight, U. S.; Binning, P. J.; Bjerg, P. L.

    2012-04-01

    Mass discharge estimates are increasingly being used in the management of contaminated sites. Such estimates have proven useful for supporting decisions related to the prioritization of contaminated sites in a groundwater catchment. Potential management options can be categorised as follows: (1) leave as is, (2) clean up, or (3) further investigation needed. However, mass discharge estimates are often very uncertain, which may hamper the management decisions. If option 1 is incorrectly chosen soil and water quality will decrease, threatening or destroying drinking water resources. The risk of choosing option 2 is to spend money on remediating a site that does not pose a problem. Choosing option 3 will often be safest, but may not be the optimal economic solution. Quantification of the uncertainty in mass discharge estimates can therefore greatly improve the foundation for selecting the appropriate management option. The uncertainty of mass discharge estimates depends greatly on the extent of the site characterization. A good approach for uncertainty estimation will be flexible with respect to the investigation level, and account for both parameter and conceptual model uncertainty. We propose a method for quantifying the uncertainty of dynamic mass discharge estimates from contaminant point sources on the local scale. The method considers both parameter and conceptual uncertainty through a multi-model approach. The multi-model approach evaluates multiple conceptual models for the same site. The different conceptual models consider different source characterizations and hydrogeological descriptions. The idea is to include a set of essentially different conceptual models where each model is believed to be realistic representation of the given site, based on the current level of information. Parameter uncertainty is quantified using Monte Carlo simulations. For each conceptual model we calculate a transient mass discharge estimate with uncertainty bounds resulting from

  11. CASE STUDY: SITE CONCEPTUAL MODEL FOR ENHANCED MNA OF ARSENIC

    EPA Science Inventory

    Field investigations have been conducted to understand the fate of arsenic in contaminated ground water during discharge into the Halls Brook Holding Area (HBHA) Pond at the Industri-Plex Superfund Site in Massachusetts. The ground water plume contains elevated levels of arsenic...

  12. Conceptual Model of Iodine Behavior in the Subsurface at the Hanford Site

    SciTech Connect

    Truex, Michael J.; Lee, Brady D.; Johnson, Christian D.; Qafoku, Nikolla P.; Last, George V.; Lee, Michelle H.; Kaplan, Daniel I.

    2015-09-01

    The fate and transport of 129I in the environment and potential remediation technologies are currently being studied as part of environmental remediation activities at the Hanford Site. A conceptual model describing the nature and extent of subsurface contamination, factors that control plume behavior, and factors relevant to potential remediation processes is needed to support environmental remedy decisions. Because 129I is an uncommon contaminant, relevant remediation experience and scientific literature are limited. Thus, the conceptual model also needs to both describe known contaminant and biogeochemical process information and to identify aspects about which additional information needed to effectively support remedy decisions. this document summarizes the conceptual model of iodine behavior relevant to iodine in the subsurface environment at the Hanford site.

  13. Three-dimensional conceptual model for the Hanford Site unconfined aquifer system: FY 1994 status report

    SciTech Connect

    Thorne, P.D.; Chamness, M.A.; Vermeul, V.R.; Macdonald, Q.C.; Schubert, S.E.

    1994-11-01

    This report documents work conducted during the fiscal year 1994 to development an improved three-dimensional conceptual model of ground-water flow in the unconfined aquifer system across the Hanford Site Ground-Water Surveillance Project, which is managed by Pacific Northwest Laboratory. The main objective of the ongoing effort to develop an improved conceptual model of ground-water flow is to provide the basis for improved numerical report models that will be capable of accurately predicting the movement of radioactive and chemical contaminant plumes in the aquifer beneath Hanford. More accurate ground-water flow models will also be useful in assessing the impacts of changes in facilities and operations. For example, decreasing volumes of operational waste-water discharge are resulting in a declining water table in parts of the unconfined aquifer. In addition to supporting numerical modeling, the conceptual model also provides a qualitative understanding of the movement of ground water and contaminants in the aquifer.

  14. Preliminary assessment of the impact of conceptual model uncertainty on site performance

    SciTech Connect

    Gallegos, D.P.; Pohl, P.I.; Olague, N.E.; Knowlton, R.G.; Updegraff, C.D.

    1990-10-01

    The US Department of Energy is responsible for the design, construction, operation, and decommission of a site for the deep geologic disposal of high-level radioactive waste (HLW). This involves site characterization and the use of performance assessment to demonstrate compliance with regulations for HLW disposal from the US Environmental Protection Agency (EPA) and the US Nuclear Regulatory Commission. The EPA standard states that a performance assessment should consider the associated uncertainties involved in estimating cumulative release of radionuclides to the accessible environment. To date, the majority of the efforts in uncertainty analysis have been directed toward data and parameter uncertainty, whereas little effort has been made to treat model uncertainty. Model uncertainty includes conceptual model uncertainty, mathematical model uncertainty, and any uncertainties derived from implementing the mathematical model in a computer code. Currently there is no systematic approach that is designed to address the uncertainty in conceptual models. The purpose of this investigation is to take a first step at addressing conceptual model uncertainty. This will be accomplished by assessing the relative impact of alternative conceptual models on the integrated release of radionuclides to the accessible environment for an HLW repository site located in unsaturated, fractured tuff. 4 refs., 2 figs.

  15. Adaptive Work Strategy for Evaluating a Conceptual Site Model

    NASA Astrophysics Data System (ADS)

    Dietrich, P.; Utom, A. U.; Werban, U.

    2015-12-01

    A comprehensive, diagnostic, procedural and adaptive scheme involving a combination of geophysical and direct push methods was developed and applied in the Wurmlingen study site situated within the region of Baden-Württemberg (southwest Germany). The goal of the study was to test the applicability of electrical resistivity method in imaging resistivity contrasts, and mapping the depth to and lateral extent of field-scale subsurface structures and existence of flow paths that may control concentration gradients of groundwater solution contents. Based on a relatively fast and cost-effective areal mapping with vertical electrical sounding technique, a northwest-southeast trending stream-channel-like depression (low apparent resistivity feature) through a Pleistocene aquifer was detected. For a more detailed characterization, we implemented electrical resistivity tomography method followed by direct push (DP) technologies. Beside the use of DP for verification of structures identified by geophysical tools, we used it for multi-level groundwater sampling. Results from groundwater chemistry indicate zones of steep nitrate concentration gradients associated with the feature.

  16. Three-dimensional conceptual model for the Hanford Site unconfined aquifer system, FY 1993 status report

    SciTech Connect

    Thorne, P.D.; Chamness, M.A.; Spane, F.A. Jr.; Vermeul, V.R.; Webber, W.D.

    1993-12-01

    The ground water underlying parts of the Hanford Site (Figure 1.1) contains radioactive and chemical contaminants at concentrations exceeding regulatory standards (Dresel et al. 1993). The Hanford Site Ground-Water Surveillance Project, operated by Pacific Northwest Laboratory (PNL), is responsible for monitoring the movement of these contaminants to ensure that public health and the environment are protected. To support the monitoring effort, a sitewide three-dimensional ground-water flow model is being developed. This report provides an update on the status of the conceptual model that will form the basis for constructing a numerical three-dimensional flow model for, the site. Thorne and Chamness (1992) provide additional information on the initial development of the three-dimensional conceptual model.

  17. Using the Conceptual Site Model to Remediate Two Sites in New England and Reach License Termination and Site Reuse

    SciTech Connect

    Glucksberg, Nadia; Peters, Jay

    2008-01-15

    The Conceptual Site Model (CSM) is a powerful tool for understanding the link between contamination sources, cleanup objectives, and ultimate site reuse. The CSM describes the site setting, geology, hydrogeology, potential sources, release mechanisms and migration pathways of contaminants. The CSM is needed to understand the extent of contamination and how receptors may be exposed to both radiological and chemical constituents. A key component of the CSM that is often overlooked concerns how the regulatory requirements drive remediation and how each has to be integrated into the CSM to ensure that all stakeholder requirements are understood and addressed. This paper describes how the use of the CSM helped reach closure and reuse at two facilities in Connecticut that are pursuing termination of their Nuclear Regulatory Commission (NRC) license. The two facilities are the Combustion Engineering Site, located in Windsor, Connecticut, (CE Windsor Site) and the Connecticut Yankee Atomic Power Company, located in Haddam Neck, Connecticut (CYAPCO). The closure of each of these facilities is regulated by four agencies: - Nuclear Regulatory Commission (NRC) - which requires cleanup levels for radionuclides to be protective of public health; - US Environmental Protection Agency (USEPA) - which requires cleanup levels for chemicals to be protective of public health and the environment; - Connecticut Department of Environmental Protection (CTDEP) Bureau of Air Management, Radiation Division - which requires cleanup levels for radionuclides to be protective of public health; and - Connecticut Department of Environmental Protection (CTDEP) Bureau of Water Protection and Land Reuse - which requires cleanup levels for chemicals to be protective of public health and the environment. Some of the radionuclides at the CE Windsor Site are also regulated under the Formerly Utilized Site Remedial Action Program (FUSRAP) under the Army Corps of Engineers. The remainder of this paper

  18. A Systematic Approach for Developing Conceptual Models of Contaminant Transport at the Hanford Site

    NASA Astrophysics Data System (ADS)

    Murray, C. J.; Last, G. V.; Rohay, V. J.; Schelling, F. J.; Hildebrand, R. D.; Morse, J. G.

    2004-12-01

    The U.S. Department of Energy (DOE) faces many decisions regarding future remedial actions and waste disposal at the Hanford Site in southeast Washington State. To support these decisions, DOE recognized the need for a comprehensive and systematic approach to developing and documenting complete, consistent, and defensible conceptual models of contaminant release and migration. After reviewing existing conceptual model development methodologies that might be applicable to environmental assessments at the Hanford Site, DOE initiated efforts to adapt and implement the Features, Events, and Processes (FEP) methodology developed for use in performance assessments of nuclear waste disposal systems by NIREX. In adapting this methodology for use in the environmental assessments at Hanford, the international list of FEPs, compiled from nuclear waste disposal programs, was evaluated to develop a list of potentially relevant Hanford-specific FEPs. The international nuclear waste programs focus on deep geologic disposal while waste disposal at the Hanford Site involves burial in shallow unconsolidated geologic deposits. Thus, a graphical tool called the Process Relationship Diagram (PRD) was created to assist in identifying the international FEPs and additional factors that are relevant to Hanford, and to illustrate the relationships among these factors. The PRD is similar in form and function to the Master Directed Diagram used by NIREX to provide a visual and systematic structure for the FEP methodology. Adaptation of this approach is showing promise in facilitating the development of conceptual models and selection of relevant factors to be incorporated into environmental uncertainty assessments for the Hanford Site.

  19. Identification of Errors in the Hanford Site-Wide Groundwater Flow Model by Inverse Modeling of Alternative Conceptual Models

    NASA Astrophysics Data System (ADS)

    Cole, C. R.; Scheibe, T. D.; Vermeul, V. R.; Wurstner, S. K.; Thorne, P. D.; Freedman, V. L.; Murray, C. J.; Bergeron, M. P.

    2002-12-01

    A regional-scale, three-dimensional groundwater flow and transport modeling effort has been undertaken to quantify the environmental consequences of past waste disposal activities and support ongoing environmental management activities at the U.S. Department of Energy's Hanford Site. An important aspect of this effort is the identification and quantification of uncertainties associated with model predictions. It is recognized that such uncertainties arise not only from selection of inappropriate groundwater model parameters (parameter error), but also from the underlying conceptualization of the groundwater system (model error). Therefore, we have adopted an approach to uncertainty characterization that involves the evaluation of multiple alternative conceptual models (ACMs) within an inverse modeling framework. The initial step in implementation of the framework was the development of a multi-processor implementation of the UCODE inverse modeling system and application of the inverse framework to update parameter estimates from a prior deterministic model. A preliminary first-order uncertainty analysis was performed based on the model results. At the same time, site geologists developed an improved conceptual model of the 3D structure of the aquifer system. Inverse modeling of the updated conceptual model led to estimates of some parameters, especially specific yield, that were not plausible, indicating that there were problems with the conceptual model. As a result, additional ACMs were developed and subjected to inverse analysis, including an alternative with modified boundary conditions (leaky underlying bedrock), an alternative incorporating surface recharge modifications based on surface run-on from an adjacent topographic feature, and an alternative incorporating an improved description of the timing and volume of waste discharges arriving at the water table (upper model boundary). Model predictions of transient hydraulic heads under each ACM were compared

  20. Offshore Wind Guidance Document: Oceanography and Sediment Stability (Version 1) Development of a Conceptual Site Model.

    SciTech Connect

    Roberts, Jesse D.; Jason Magalen; Craig Jones

    2014-06-01

    This guidance document provide s the reader with an overview of the key environmental considerations for a typical offshore wind coastal location and the tools to help guide the reader through a thoro ugh planning process. It will enable readers to identify the key coastal processes relevant to their offshore wind site and perform pertinent analysis to guide siting and layout design, with the goal of minimizing costs associated with planning, permitting , and long - ter m maintenance. The document highlight s site characterization and assessment techniques for evaluating spatial patterns of sediment dynamics in the vicinity of a wind farm under typical, extreme, and storm conditions. Finally, the document des cribe s the assimilation of all of this information into the conceptual site model (CSM) to aid the decision - making processes.

  1. Joint Assessment of Parameter and Conceptual Model Uncertainty at the Hanford Site 300 Area

    NASA Astrophysics Data System (ADS)

    Meyer, P. D.; Ye, M.; Neuman, S. P.

    2005-12-01

    Assessment of conceptual model and parameter uncertainties is important for science-based decision making, long-term stewardship and monitoring network design. We use the recently developed Maximum Likelihood Bayesian Model Averaging (MLBMA) method to assess jointly the uncertainty associated with alternative flow and transport models, and their parameters, at the 300 Area of the DOE Hanford Site in Washington. Eight groundwater flow and transport model alternatives are considered representing various levels of model complexity, e.g., the degree to which they resolve temporal variations in river stage and spatial variations in hydraulic and transport parameters. The eight models are implemented using MODFLOW and MT3DMS in conjunction with the statistical parameter estimation package PEST and its sensitivity routine SENSAN within the framework of GMS (Groundwater Modeling System). Each of the eight flow and transport models is calibrated jointly against site measurements of hydraulic head and concentration. Parameters found to be insensitive to these measurements and measurements found to have negligible effect on model parameters are excluded from the calibration. The relative plausibility of each calibrated model is expressed in terms of a posterior model probability computed on the basis of Kashyap's information criterion KIC. Models having relatively small posterior probabilities are discarded and those with relatively large posterior probabilities are retained to obtain MLBMA predictions of flow and transport at the site. This is done by (a) using the parameter estimates and their covariance matrices to generate numerous Monte Carlo realizations of model parameters; (b) generating corresponding realizations of predicted heads, concentrations and fluxes; (c) computing the mean and variance of these quantities over all realizations; and (d) averaging the latter over all models using their posterior probabilities as weights. We conclude by comparing the predictive

  2. Karstification beneath dam-sites: From conceptual models to realistic scenarios

    NASA Astrophysics Data System (ADS)

    Hiller, Thomas; Kaufmann, Georg; Romanov, Douchko

    2011-02-01

    SummaryDam-sites and reservoirs located above soluble rock are often damaged by increased leakage through the sub-surface within the life-time of the structure. The high hydraulic gradients driving the water through the fracture and fissure system of the bedrock have a strong impact on the aquifer evolution. The increased permeability, if not prevented, leads to an imminent danger of high leakage rates (breakthrough) as well. As a result, the structural safety of the dam-site itself is at risk. Past experience has shown that this may have large environmental and economical consequences. For a better understanding of the evolution of karst aquifer systems in the vicinity of dam-sites, a three-dimensional conceptual model is presented. We show the evolution of the karst aquifer for simple three-dimensional dam-site setups. Keeping the symmetry and simplicity of the models we can relate our results to the two- and one-dimensional scenarios presented in the past. Implementing a statistical fracture network and topographic information to this basic setup we show that these complex three-dimensional properties of the real aquifers, have a significant influence on the karstification, and cannot always be addressed by two -and one-dimensional models.

  3. Comparison of Model Error for Alternative Conceptual Models of Sediment Geometry at the Hanford Site, Southeast Washington

    NASA Astrophysics Data System (ADS)

    Murray, C. J.; Savelieva-Trofimova, E. A.; Thorne, P. D.; Xie, Y.; Scheibe, T. D.; Cole, C. R.; Kanevski, M.

    2002-12-01

    A number of uncertainties exist in the hydrogeology of the Hanford Site, and the high costs and risks associated with cleanup of sites contaminated with radioactive wastes requires that the uncertainty associated with alternative remediation decisions must fully reflect the uncertainty associated with these decisions. Prior uncertainty analyses of Hanford groundwater model predictions have focused on uncertainties in model parameters (e.g., hydraulic conductivity) given an assumed conceptual model of hydrogeologic structure. In this study we evaluated predictive uncertainty related to the model structure conceptualization. Our study has focused on two major elements of the hydrogeologic structure of the Hanford Site: the geometry of mud units that occur within the aquifer, and the parameter zonation for hydrologic properties of the uppermost conductive portion of the aquifer. For each structural element, we have developed alternative conceptual models that have been evaluated by inverse modeling. The geometry and continuity of mud units exert a strong influence on groundwater flow and contaminant transport at the site. A detailed study of the spatial distribution of the three mud units was performed using a data set consisting of the presence/absence of each mud unit at several hundred boreholes, as well as the thickness if a mud unit was present. The spatial analysis proceeded in two stages. A series of stochastic simulations of the mud units were prepared using geostatistical methods. The stochastic simulations were numerically ranked and a subset of the best and worst simulations (as determined by the connectedness of the aquifer given the simulated mud distributions) was used as inputs to an inverse model. Inverse modeling was performed using UCODE and a finite element flow and transport code (CFEST) and used to test the fit of over 76,000 observed potentiometric head data for several alternative models of the mud distribution. Those conceptual models included

  4. SAMPLING PROTOCOLS TO SUPPORT DEVELOPMENT OF CONCEPTUAL SITE MODELS AND CLEANUP DECISIONS FOR CONTAMINANTS IN GROUND WATER

    EPA Science Inventory

    The ability to make reliable decisions about the extent of subsurface contamination and approaches to restoration of contaminated ground water is dependent on the development of an accurate conceptual site model (CSM). The accuracy of the CSM is dependent on the quality of site ...

  5. Conceptual model for regional radionuclide transport from a basalt repository site. Final draft, technical memorandum

    SciTech Connect

    Walton, W.C.; Voorhees, M.L.; Prickett, T.A.

    1980-05-23

    This technical memorandum was prepared to: (1) describe a typical basalt radionuclide repository site, (2) describe geologic and hydrologic processes associated with regional radionuclide transport in basalts, (3) define the parameters required to model regional radionuclide transport from a basalt repository site, and (4) develop a ''conceptual model'' of radionuclide transport from a basalt repository site. In a general hydrological sense, basalts may be described as layered sequences of aquifers and aquitards. The Columbia River Basalt, centered near the semi-arid Pasco Basin, is considered by many to be typical basalt repository host rock. Detailed description of the flow system including flow velocities with high-low hydraulic conductivity sequences are not possible with existing data. However, according to theory, waste-transport routes are ultimately towards the Columbia River and the lengths of flow paths from the repository to the biosphere may be relatively short. There are many physical, chemical, thermal, and nuclear processes with associated parameters that together determine the possible pattern of radionuclide migration in basalts and surrounding formations. Brief process descriptions and associated parameter lists are provided. Emphasis has been placed on the use of the distribution coefficient in simulating ion exchange. The use of the distribution coefficient approach is limited because it takes into account only relatively fast mass transfer processes. In general, knowledge of hydrogeochemical processes is primitive.

  6. Field studies at the Apache Leap Research Site in support of alternative conceptual models

    SciTech Connect

    Woodhouse, E.G.; Davidson, G.R.; Theis, C.

    1997-08-01

    This is a final technical report for a project of the U.S Nuclear Regulatory Commission (sponsored contract NRC-04-090-51) with the University of Arizona. The contract was an optional extension that was initiated on July 21, 1994 and that expired on May 31, 1995. The project manager was Thomas J. Nicholson, Office of Nuclear Regulatory Research. The objectives of this contract were to examine hypotheses and conceptual models concerning unsaturated flow and transport through fractured rock, and to design and execute confirmatory field and laboratory experiments to test these hypotheses and conceptual models at the Apache Leap Research Site near Superior, Arizona. The results discussed here are products of specific tasks that address a broad spectrum of issues related to flow and transport through fractures. Each chapter in this final report summarizes research related to a specific set of objectives and can be read and interpreted as a separate entity. The tasks include detection and characterization of historical rapid fluid flow through fractured rock and the relationship to perched water systems using environmental isotopic tracers of {sup 3}H and {sup 14}C, fluid- and rock-derived {sup 2343}U/{sup 238}U measurements, and geophysical data. The water balance in a small watershed at the ALRS demonstrates the methods of acounting for ET, and estimating the quantity of water available for infiltration through fracture networks. Grain density measurements were made for core-sized samples using a newly designed gas pycnometer. The distribution and magnitude of air permeability measurements have been measured in a three-dimensional setting; the subsequent geostatistical analysis is presented. Electronic versions of the data presented here are available from authors; more detailed discussions and analyses are available in technical publications referenced herein, or soon to appear in the professional literature.

  7. Integrating intrusive and nonintrusive characterization methods to achieve a conceptual site model for the SLDA FUSRAP site - 8265.

    SciTech Connect

    Durham, L. A.; Peterson, J. M.; Frothingham, D. G.; Frederick, W. T.; Lenart, W.; Environmental Science Division; U. S. Army Corps of Engineers, Pittsburg District; U. S. Army Corps of Engineers, Buffalo District

    2008-01-01

    data and information from these sources were used to refine the conceptual site model, complete the RI/FS, and support the ongoing remedial design and action, which will achieve site closure acceptable to all stakeholders.

  8. A conceptual model for assessing risks in a Mediterranean Natura 2000 Network site.

    PubMed

    Macedo-Sousa, Joaquim A; Soares, Amadeu M V M; Tarazona, José V

    2009-01-15

    Every year millions of tons of chemical products are disposed to the environment as a result of human activities, with deleterious consequences to biodiversity. In Europe the biodiversity policy basis for action is provided by the Birds and the Habitats Directives. According to these directives a network of protected areas is being built across EU countries encompassing the Natura 2000 Network. But the management plans of these protected areas do not require an ecotoxicological assessment of chemicals used within its limits. As for risk assessment protocols described in EC pieces of legislation and technical guidance documents, they are generic guidelines that not take into consideration regional particularities, e.g. the Mediterranean ecoregion specificities, and its local ecological values. Herewith we present a conceptual model for the assessment of risks posed by agriculture to bird species of conservationist concern from Natura 2000 Network sites; an example is set in a cereal steppe of the Iberian Peninsula. Hazards identified are related to the utilization of herbicides, disposal of sewage sludge to be used as fertilizer, and the input of veterinary pharmaceuticals that can be found in livestock dung and urine. This innovative model, to be used in high tier risk assessment, takes into account the biotic parameters of the protected bird species: great bustard (Otis tarda), lesser kestrel (Falco naumanni), and montagu's harrier (Circus pygargus). The transfer of chemicals is considered to occur mainly through a realistic trophic chain scenario according to the different feeding behaviour among different species and even within the same species when having different feeding habits (e.g. adults and juveniles). Moreover, the probabilistic approach is proposed in order to perform a transparent risk assessment and clearer risk communication. PMID:18990432

  9. Use of a Local-Scale Numerical Model to Resolve Conceptual Model Issues at Lawrence Livermore National Laboratory's Site 300.

    NASA Astrophysics Data System (ADS)

    Ritcey, A. C.; Maley, M. P.; Mansoor, K.; Blake, R. G.

    2001-12-01

    A finite-element model was developed to simulate saturated-zone groundwater flow and contaminant transport within the Building 832 Canyon Operating Unit (B832) located at Lawrence Livermore National Laboratory's Site 300. Site 300 is an experimental testing facility located in the Altamont Hills near Tracy, California. The Altamont Hills are located along the easternmost flank of the California Coast Range, and are characterized by steep topography, faulting and folding. Beginning in the 1950s, experimental activities were conducted at B832 that resulted in the release of high concentrations of trichloroethene (TCE) to the subsurface. The primary objective of the numerical model was to investigate the influence of local geologic features on groundwater flow and contaminant transport. The model was designed to easily allow modifications to the conceptual model, and was limited to a single hydrostratigraphic unit (HSU) composed of a thin, (10m thick) sandstone layer within the Neroly Formation that is defined as the primary contaminant pathway. The finite-element code FEFLOW was used for the simulations. Two local-scale features, a fault and a small discharge area, were incorporated into the model, and their effects on flow and transport evaluated by comparison with observed data. The model was also used to evaluate the effects of local-boundary treatments on model results. In particular, the sensitivity of the model to boundary conditions along the western portion of the model domain was evaluated, instigating a re-evaluation of ground-water elevation data in this area. Overall, the local-scale model provided an excellent tool for understanding and refining the conceptual model. The model will also provide boundary conditions (e.g. ground water and TCE fluxes) for a larger-scale model of Site 300's regional aquifer. In addition, the single HSU model allows debugging of boundary conditions in a simpler, more computationally-efficient environment prior to development

  10. Conceptual Model of Uranium in the Vadose Zone for Acidic and Alkaline Wastes Discharged at the Hanford Site Central Plateau

    SciTech Connect

    Truex, Michael J.; Szecsody, James E.; Qafoku, Nikolla; Serne, R. Jeffrey

    2014-09-01

    Historically, uranium was disposed in waste solutions of varying waste chemistry at the Hanford Site Central Plateau. The character of how uranium was distributed in the vadose zone during disposal, how it has continued to migrate through the vadose zone, and the magnitude of potential impacts on groundwater are strongly influenced by geochemical reactions in the vadose zone. These geochemical reactions can be significantly influenced by the disposed-waste chemistry near the disposal location. This report provides conceptual models and supporting information to describe uranium fate and transport in the vadose zone for both acidic and alkaline wastes discharged at a substantial number of waste sites in the Hanford Site Central Plateau. The conceptual models include consideration of how co-disposed acidic or alkaline fluids influence uranium mobility in terms of induced dissolution/precipitation reactions and changes in uranium sorption with a focus on the conditions near the disposal site. This information, when combined with the extensive information describing uranium fate and transport at near background pH conditions, enables focused characterization to support effective fate and transport estimates for uranium in the subsurface.

  11. The site-scale saturated zone flow model for Yucca Mountain: calibration of different conceptual models and their impact on flow paths.

    PubMed

    Zyvoloski, George; Kwicklis, Edward; Eddebbarh, Al Aziz; Arnold, Bill; Faunt, Claudia; Robinson, Bruce A

    2003-01-01

    This paper presents several different conceptual models of the Large Hydraulic Gradient (LHG) region north of Yucca Mountain and describes the impact of those models on groundwater flow near the potential high-level repository site. The results are based on a numerical model of site-scale saturated zone beneath Yucca Mountain. This model is used for performance assessment predictions of radionuclide transport and to guide future data collection and modeling activities. The numerical model is calibrated by matching available water level measurements using parameter estimation techniques, along with more informal comparisons of the model to hydrologic and geochemical information. The model software (hydrologic simulation code FEHM and parameter estimation software PEST) and model setup allows for efficient calibration of multiple conceptual models. Until now, the Large Hydraulic Gradient has been simulated using a low-permeability, east-west oriented feature, even though direct evidence for this feature is lacking. In addition to this model, we investigate and calibrate three additional conceptual models of the Large Hydraulic Gradient, all of which are based on a presumed zone of hydrothermal chemical alteration north of Yucca Mountain. After examining the heads and permeabilities obtained from the calibrated models, we present particle pathways from the potential repository that record differences in the predicted groundwater flow regime. The results show that Large Hydraulic Gradient can be represented with the alternate conceptual models that include the hydrothermally altered zone. The predicted pathways are mildly sensitive to the choice of the conceptual model and more sensitive to the quality of calibration in the vicinity on the repository. These differences are most likely due to different degrees of fit of model to data, and do not represent important differences in hydrologic conditions for the different conceptual models. PMID:12714319

  12. 1994 conceptual model of the carbon tetrachloride contamination in the 200 West Area at the Hanford Site

    SciTech Connect

    Rohay, V.J.

    1994-08-01

    Between 1955 and 1973, a total of 363,000 to 580,000 L (577,000 to kg) of liquid carbon tetrachloride, in mixtures with other organic and aqueous, actinide-bearing fluids, were discharged to the soil column at three disposal facilities -- the 216-Z-9 Trench, the 216-Z-lA TiTe Field, and the 216-Z-18 Crib -- in the 200 West Area at the Hanford Site. In the mid-1980`s, dissolved carbon tetrachloride was found in the uppermost aquifer beneath the disposal facilities, and in late 1990, the US Environmental Protection Agency and the Washington State Department of Ecology requested that the US Department of Energy proceed with planning and implementation of an expedited response action (ERA) to minimize additional carbon tetrachloride contamination of the groundwater. In February 1992, soil vapor extraction was initiated to remove carbon tetrachloride from the unsaturated zone beneath these disposal facilities. By May 1994, a total of 10,560 L (16,790 kg) of carbon tetrachloride had been removed, amounting to an estimated 2% of the discharged inventory. In the spring of 1991, the Volatile Organic Compounds -- Arid Integrated Demonstration (VOC-Arid ID) program selected the carbon tetrachloride-contaminated site for demonstration and deployment of new technologies for evaluation and cleanup of volatile organic compounds and associated contaminants in soils and groundwater at arid sites. Site investigations conducted in support of both the ERA and the VOC-Arid ID have been integrated because of their shared objective to refine the conceptual model of the site and to promote efficiency. Site characterization data collected in fiscal year 1993 have supported and led to refinement of the conceptual model of the carbon tetrachloride site.

  13. Using integrated geospatial mapping and conceptual site models to guide risk-based environmental clean-up decisions.

    PubMed

    Mayer, Henry J; Greenberg, Michael R; Burger, Joanna; Gochfield, Michael; Powers, Charles; Kosson, David; Keren, Roger; Danis, Christine; Vyas, Vikram

    2005-04-01

    Government and private sector organizations are increasingly turning to the use of maps and other visual models to provide a depiction of environmental hazards and the potential risks they represent to humans and ecosystems. Frequently, the graphic presentation is tailored to address a specific contaminant, its location and possible exposure pathways, and potential receptors. Its format is usually driven by the data available, choice of graphics technology, and the audience being served. A format that is effective for displaying one contaminant at one scale at one site, however, may be ineffective in accurately portraying the circumstances surrounding a different contaminant at the same site, or the same contaminant at a different site, because of limitations in available data or the graphics technology being used. This is the daunting challenge facing the U.S. Department of Energy (DOE), which is responsible for the nation's legacy wastes from nuclear weapons research, testing, and production at over 100 sites in the United States. In this article, we discuss the development and use of integrated geospatial mapping and conceptual site models to identify hazards and evaluate alternative long-term environmental clean-up strategies at DOE sites located across the United States. While the DOE probably has the greatest need for such information, the Department of Defense and other public and private responsible parties for many large and controversial National Priority List or Superfund sites would benefit from a similar approach. PMID:15876215

  14. A Comprehensive and Systematic Approach to Developing and Documenting Conceptual Models of Contaminant Release and Migration at the Hanford Site

    SciTech Connect

    Last, George V.; Rohay, Virginia J.; Schelling, F J.; Bunn, Amoret L.; Delamare, Michael A.; Dirkes, Roger L.; Hildebrand, R D.; Morse, John G.; Napier, Bruce A.; Riley, Robert G.; Soler, Luis; Thorne, Paul D.

    2004-04-01

    The U. S. Department of Energy?s Richland Operations Office has initiated efforts to adapt and implement the Features, Events, and Processes (FEPs) methodology (used in scenario development for nuclear waste disposal programs) to the environmental management and remediation problems facing the Hanford Site. These efforts have shown that modification of the FEPs methodology to incorporate the use of Process Relationship Diagrams (PRD) is effective in facilitating the development of conceptual models and selection of potentially relevant factors to be incorporated into a specific performance assessment. In developing this methodology for Hanford, a master PRD was created to provide an organization structure for identifying the potentially relevant factors (i.e. FEPs) and for illustrating the relationships between these factors. This organizational framework was developed to match the organization of current Hanford site-wide performance assessment activities and to facilitate screening of the FEPs relevant to the problems (and conceptual models) that need to be addressed at the site. However, the link between Hanford specific FEPs and the international list of FEPs was maintained to demonstrate completeness and perhaps to expand the usefulness of the international list for other environmental programs.

  15. Case study of contaminated groundwater discharge: how in situ tools link an evolving conceptual site model with management decisions.

    PubMed

    Duncan, P Bruce; Greenberg, Marc S; Leja, Stan; Williams, Jonathan; Black, Curt; Henry, Richard G; Wilhelm, Leon

    2007-04-01

    In this paper, we show how simple in situ tools provide key insights into groundwater transport and exposure pathways. We illustrate how integration between managers, hydrogeologists, and ecologists, through the use of an evolving conceptual site model, helps direct management decisions. An initial conceptual site model was used to guide a preliminary investigation to determine the extent to which contaminant exposure from discharging groundwater occurs in a waterway. Regulatory agency managers, informed by phased input of data, supported extending the site investigation subtidally to identify the nature and extent of waterway contamination and to provide the basis for developing remedial alternatives. Approaches and tools used in this reconnaissance investigation included monitoring ambient surface water for groundwater signatures, installing minipiezometers within the sediment, and installing diffusion samplers and seepage meters. Despite high concentrations of contaminants in nearby piezometer samples, the diffusion sampler array indicated few locations with contaminant accumulation in the top 20 cm of the sediment. At the location where deployed, seepage meters demonstrated a high degree of connectivity and the potential for mass loading in the waterway. In the collective experience of the authors, this is one of the 1st sites where this comprehensive suite of tools has been applied in a regulatory setting to evaluate the movement of industrial contaminants beneath and into a waterway. This approach was effective because of integration of disciplines, unification of previously separate groundwater and sediment investigations, and collaboration across separate agencies and programs. In large part because of the results, the facility and agency managers agreed, and have begun a comprehensive subtidal investigation, to characterize the distribution of sediment and groundwater contamination and to quantify the groundwater flux to the surface water. PMID:17477296

  16. Predicting DNAPL mass discharge and contaminated site longevity probabilities: Conceptual model and high-resolution stochastic simulation

    NASA Astrophysics Data System (ADS)

    Koch, J.; Nowak, W.

    2015-02-01

    Improper storage and disposal of nonaqueous-phase liquids (NAPLs) has resulted in widespread contamination of the subsurface, threatening the quality of groundwater as a freshwater resource. The high frequency of contaminated sites and the difficulties of remediation efforts demand rational decisions based on a sound risk assessment. Due to sparse data and natural heterogeneities, this risk assessment needs to be supported by appropriate predictive models with quantified uncertainty. This study proposes a physically and stochastically coherent model concept to simulate and predict crucial impact metrics for DNAPL contaminated sites, such as contaminant mass discharge and DNAPL source longevity. To this end, aquifer parameters and the contaminant source architecture are conceptualized as random space functions. The governing processes are simulated in a three-dimensional, highly resolved, stochastic, and coupled model that can predict probability density functions of mass discharge and source depletion times. While it is not possible to determine whether the presented model framework is sufficiently complex or not, we can investigate whether and to which degree the desired model predictions are sensitive to simplifications often found in the literature. By testing four commonly made simplifications, we identified aquifer heterogeneity, groundwater flow irregularity, uncertain and physically based contaminant source zones, and their mutual interlinkages as indispensable components of a sound model framework.

  17. Transient Inverse Calibration of Site-Wide Groundwater Model to Hanford Operational Impacts from 1943 to 1996--Alternative Conceptual Model Considering Interaction with Uppermost Basalt Confined Aquifer

    SciTech Connect

    Vermeul, Vincent R.; Cole, Charles R.; Bergeron, Marcel P.; Thorne, Paul D.; Wurstner, Signe K.

    2001-08-29

    The baseline three-dimensional transient inverse model for the estimation of site-wide scale flow parameters, including their uncertainties, using data on the transient behavior of the unconfined aquifer system over the entire historical period of Hanford operations, has been modified to account for the effects of basalt intercommunication between the Hanford unconfined aquifer and the underlying upper basalt confined aquifer. Both the baseline and alternative conceptual models (ACM-1) considered only the groundwater flow component and corresponding observational data in the 3-Dl transient inverse calibration efforts. Subsequent efforts will examine both groundwater flow and transport. Comparisons of goodness of fit measures and parameter estimation results for the ACM-1 transient inverse calibrated model with those from previous site-wide groundwater modeling efforts illustrate that the new 3-D transient inverse model approach will strengthen the technical defensibility of the final model(s) and provide the ability to incorporate uncertainty in predictions related to both conceptual model and parameter uncertainty. These results, however, indicate that additional improvements are required to the conceptual model framework. An investigation was initiated at the end of this basalt inverse modeling effort to determine whether facies-based zonation would improve specific yield parameter estimation results (ACM-2). A description of the justification and methodology to develop this zonation is discussed.

  18. Groundwater monitoring program plan and conceptual site model for the Al-Tuwaitha Nuclear Research Center in Iraq.

    SciTech Connect

    Copland, John Robin; Cochran, John Russell

    2013-07-01

    The Radiation Protection Center of the Iraqi Ministry of Environment is developing a groundwater monitoring program (GMP) for the Al-Tuwaitha Nuclear Research Center located near Baghdad, Iraq. The Al-Tuwaitha Nuclear Research Center was established in about 1960 and is currently being cleaned-up and decommissioned by Iraq's Ministry of Science and Technology. This Groundwater Monitoring Program Plan (GMPP) and Conceptual Site Model (CSM) support the Radiation Protection Center by providing:A CSM describing the hydrogeologic regime and contaminant issues,recommendations for future groundwater characterization activities, anddescriptions of the organizational elements of a groundwater monitoring program. The Conceptual Site Model identifies a number of potential sources of groundwater contamination at Al-Tuwaitha. The model also identifies two water-bearing zones (a shallow groundwater zone and a regional aquifer). The depth to the shallow groundwater zone varies from approximately 7 to 10 meters (m) across the facility. The shallow groundwater zone is composed of a layer of silty sand and fine sand that does not extend laterally across the entire facility. An approximately 4-m thick layer of clay underlies the shallow groundwater zone. The depth to the regional aquifer varies from approximately 14 to 17 m across the facility. The regional aquifer is composed of interfingering layers of silty sand, fine-grained sand, and medium-grained sand. Based on the limited analyses described in this report, there is no severe contamination of the groundwater at Al-Tuwaitha with radioactive constituents. However, significant data gaps exist and this plan recommends the installation of additional groundwater monitoring wells and conducting additional types of radiological and chemical analyses.

  19. Borehole Completion and Conceptual Hydrogeologic Model for the IFRC Well Field, 300 Area, Hanford Site

    SciTech Connect

    Bjornstad, Bruce N.; Horner, Jacob A.; Vermeul, Vincent R.; Lanigan, David C.; Thorne, Paul D.

    2009-04-20

    A tight cluster of 35 new wells was installed over a former waste site, the South Process Pond (316-1 waste site), in the Hanford Site 300 Area in summer 2008. This report documents the details of the drilling, sampling, and well construction for the new array and presents a summary of the site hydrogeology based on the results of drilling and preliminary geophysical logging.

  20. Conceptual IT model

    NASA Astrophysics Data System (ADS)

    Arnaoudova, Kristina; Stanchev, Peter

    2015-11-01

    The business processes are the key asset for every organization. The design of the business process models is the foremost concern and target among an organization's functions. Business processes and their proper management are intensely dependent on the performance of software applications and technology solutions. The paper is attempt for definition of new Conceptual model of IT service provider, it could be examined as IT focused Enterprise model, part of Enterprise Architecture (EA) school.

  1. Conceptual Model of the Geometry and Physics of Water Flow in a Fractured Basalt Vadose Zone: Box Canyon Site, Idaho

    SciTech Connect

    Faybishenko, Boris; Doughty, Christine; Steiger, Michael; Long, Jane C.S.; Wood, Tom; Jacobsen, Janet; Lore, Jason; Zawislanski, Peter T.

    1999-03-01

    A conceptual model of the geometry and physics of water flow in a fractured basalt vadose zone was developed based on the results of lithological studies and a series of ponded infiltration tests conducted at the Box Canyon site near the Idaho National Engineering and Environmental Laboratory (INEEL) in Idaho. The infiltration tests included one two-week test in 1996, three two-day tests in 1997, and one four-day test in 1997. For the various tests, initial infiltration rates ranged from 4.1 cm/day to 17.7 cm/day and then decreased with time, presumably due to mechanical or microbiological clogging of fractures and vesicularbasalt in the near-surface zone, as well as the effect of entrapped air. The subsurface moisture redistribution was monitored with tensiometers, neutron logging, time domain reflectrometry and ground penetrating radar. A conservative tracer, potassium bromide, was added to the pond water at a concentration of 3 g/L to monitor water flow with electrical resistivity probes and water sampling. Analysis of the data showed evidence of preferential flow rather than the propagation of a uniform wetting front. We propose a conceptual model describing the saturation-desaturation behavior of the basalt, in which rapid preferential flow through vertical column-bounding fractures occurs from the surface to the base of the basalt flow. After the rapid wetting of column-bounding fractures, a gradual wetting of other fractures and the basalt matrix occurs. Fractures that are saturated early in the tests may become desaturated thereafter, which we attribute to the redistribution of water between fractures and matrix. Lateral movement of water was also observed within a horizontal central fracture zone and rubble zone, which could have important implications for contaminant accumulation at contaminated sites.

  2. Information on Hydrologic Conceptual Models, Parameters, Uncertainty Analysis, and Data Sources for Dose Assessments at Decommissioning Sites

    SciTech Connect

    Meyer, Philip D.; Gee, Glendon W.; Nicholson, Thomas J.

    2000-02-28

    This report addresses issues related to the analysis of uncertainty in dose assessments conducted as part of decommissioning analyses. The analysis is limited to the hydrologic aspects of the exposure pathway involving infiltration of water at the ground surface, leaching of contaminants, and transport of contaminants through the groundwater to a point of exposure. The basic conceptual models and mathematical implementations of three dose assessment codes are outlined along with the site-specific conditions under which the codes may provide inaccurate, potentially nonconservative results. In addition, the hydrologic parameters of the codes are identified and compared. A methodology for parameter uncertainty assessment is outlined that considers the potential data limitations and modeling needs of decommissioning analyses. This methodology uses generic parameter distributions based on national or regional databases, sensitivity analysis, probabilistic modeling, and Bayesian updating to incorporate site-specific information. Data sources for best-estimate parameter values and parameter uncertainty information are also reviewed. A follow-on report will illustrate the uncertainty assessment methodology using decommissioning test cases.

  3. An investigation of the impact of conceptual model uncertainty on the estimated performance of a hypothetical high-level nuclear waste repository site in unsaturated, fractured tuff; Yucca Mountain Site Characterization Project

    SciTech Connect

    Gallegos, D.P.; Phol, P.I.; Updegraff, C.D.

    1992-04-01

    Performance assessment modeling for High Level Waste (HLW) disposal incorporates three different types of uncertainty. These include data and parameter uncertainty, modeling uncertainty (which includes conceptual, mathematical, and numerical), and uncertainty associated with predicting the future state of the system. In this study, the potential impact of conceptual model uncertainty on the estimated performance of a hypothetical high-level radioactive waste disposal site in unsaturated, fractured tuff has been assessed for a given group of conceptual models. This was accomplished by taking a series of six, one-dimensional conceptual models, which differed only by the fundamental assumptions used to develop them, and conducting ground-water flow and radionuclide transport simulations. Complementary cumulative distribution functions (CCDFs) representing integrated radionuclide release to the water table indicate that differences in the basic assumptions used to develop conceptual models can have a significant impact on the estimated performance of the site. Because each of the conceptual models employed the same mathematical and numerical models, contained the same data and parameter values and ranges, and did not consider the possible future states of the system, changes in the CCDF could be attributed primarily to differences in conceptual modeling assumptions. Studies such as this one could help prioritize site characterization activities by identifying critical and uncertain assumptions used in model development, thereby providing guidance as to where reduction of uncertainty is most important.

  4. Integrating Intrusive and Non-intrusive Characterization Methods To Achieve A Conceptual Site Model For The SLDA FUSRAP

    SciTech Connect

    Durham, L.A.; Peterson, J.M.; Frothingham, D.G.; Frederick, W.T.; Lenart, W.

    2008-07-01

    trenches. The data and information from these sources were used to refine the conceptual site model, complete the RI/FS, and support the ongoing remedial design and action, which will achieve site closure acceptable to all stakeholders. (authors)

  5. A Conceptual Site Model for Nature and Extent of Contamination in a Riparian-Near Shore Area - 12410

    SciTech Connect

    Morgans, Donna; Lowe, John; McCarthy, Chris; Aly, Alaa

    2012-07-01

    The 100-K decision area is located along the Columbia River and includes source Operable Units (OUs), a groundwater OU, and the adjacent surface water, saturated sediment and aquatic biota. A conceptual site model (CSM) has been developed to evaluate concentrations of non-radiological substances and radionuclides detected in soil, water and sediments in a riparian near-shore area along the Columbia River. The CSM is used to determine if potential transport pathways exist to these media from Hanford Site sources by incorporating information from the physical system, surface hydrology, subsurface hydrogeology, analytical results, and ecological evaluation into the model. Six contaminants of ecological concern, mostly metals and non-radiological inorganics, have been identified in riparian and near-shore media. With few exceptions (notably chromium and hexavalent chromium), there are ambient sources for these constituents in soil, sediment and water that are unrelated to the Hanford Site. While the CSM documented analytical and biological conditions, this paper presents results focused on analytical measurements to document the potential for these contaminants to be related to a release from the Hanford Site. The purpose for preparing this CSM was to address, on a reactor decision area basis, the potential for Hanford Site contaminants in soil or groundwater to migrate to riparian or near-shore areas at concentrations that could be of concern for ecological receptors. This CSM supplements the analysis of River Corridor-wide ecological risks presented in the ecological risk assessment of the RCBRA. The RCBRA identified on a site-wide basis some contaminants of ecological concern that warranted further evaluation. Based on the results of the further evaluation contained in this CSM, with the exception of hexavalent chromium, detected concentrations of contaminants in riparian or near-shore media are not reliably detectable at levels of ecological concern, or are not

  6. Refinement of the Kansas City Plant site conceptual model with respect to dense non-aqueous phase liquids (DNAPL)

    SciTech Connect

    Korte, N.E.; Hall, S.C.; Baker, J.L.

    1995-10-01

    This document presents a refinement of the site conceptual model with respect to dense non-aqueous phase liquid (DNAPL) at the US Department of Energy Kansas City Plant (KCP). This refinement was prompted by a review of the literature and the results of a limited study that was conducted to evaluate whether pools of DNAPL were present in contaminated locations at the KCP. The field study relied on the micropurge method of sample collection. This method has been demonstrated as a successful approach for obtaining discrete samples within a limited aquifer zone. Samples were collected at five locations across 5-ft well screens located at the base of the alluvial aquifer at the KCP. The hypothesis was that if pools of DNAPL were present, the dissolved concentration would increase with depth. Four wells with highly contaminated groundwater were selected for the test. Three of the wells were located in areas where DNAPL was suspected, and one where no DNAPL was believed to be present. The results demonstrated no discernible pattern with depth for the four wells tested. A review of the data in light of the available technical literature suggests that the fine-grained nature of the aquifer materials precludes the formation of pools. Instead, DNAPL is trapped as discontinuous ganglia that are probably widespread throughout the aquifer. The discontinuous nature of the DNAPL distribution prevents the collection of groundwater samples with concentrations approaching saturation. Furthermore, the results indicate that attempts to remediate the aquifer with conventional approaches will not result in restoration to pristine conditions because the tortuous groundwater flow paths will inhibit the efficiency of fluid-flow-based treatments.

  7. Status report on the development of a three-dimensional conceptual model for the Hanford Site unconfined aquifer system

    SciTech Connect

    Thorne, P.D.; Chamness, M.A.

    1992-11-01

    This report presents the status of development of a three-dimensional conceptual model for the unconfined aquifer system at Hanford. A conceptual model is needed to support development of a realistic three-dimensional numerical model for predicting ground-water flow and the transport of contaminants. The report focuses on developing a hydrogeologic framework, assessing available hydraulic property data, describing flow-system boundaries, and evaluating areal recharge and leakage. Geologic descriptions of samples obtained during well drilling were used to prepare cross sections that correlate relatively continuous layers. The layers were defined based on textural differences that are expected to reflect differences in hydraulic properties. Assigning hydraulic properties to the layers is a critical part of the conceptual model. Available hydraulic property data for the study area were compiled and were correlated with the geologic layers where possible. Flow-system boundaries are present within the study area at basalt outcrops and at the Columbia River. Boundary conditions have been evaluated for these areas. Available estimates of areal recharge from precipitation were compiled.

  8. Combined Estimation of Hydrogeologic Conceptual Model, Parameter, and Scenario Uncertainty with Application to Uranium Transport at the Hanford Site 300 Area

    SciTech Connect

    Meyer, Philip D.; Ye, Ming; Rockhold, Mark L.; Neuman, Shlomo P.; Cantrell, Kirk J.

    2007-07-30

    This report to the Nuclear Regulatory Commission (NRC) describes the development and application of a methodology to systematically and quantitatively assess predictive uncertainty in groundwater flow and transport modeling that considers the combined impact of hydrogeologic uncertainties associated with the conceptual-mathematical basis of a model, model parameters, and the scenario to which the model is applied. The methodology is based on a n extension of a Maximum Likelihood implementation of Bayesian Model Averaging. Model uncertainty is represented by postulating a discrete set of alternative conceptual models for a site with associated prior model probabilities that reflect a belief about the relative plausibility of each model based on its apparent consistency with available knowledge and data. Posterior model probabilities are computed and parameter uncertainty is estimated by calibrating each model to observed system behavior; prior parameter estimates are optionally included. Scenario uncertainty is represented as a discrete set of alternative future conditions affecting boundary conditions, source/sink terms, or other aspects of the models, with associated prior scenario probabilities. A joint assessment of uncertainty results from combining model predictions computed under each scenario using as weight the posterior model and prior scenario probabilities. The uncertainty methodology was applied to modeling of groundwater flow and uranium transport at the Hanford Site 300 Area. Eight alternative models representing uncertainty in the hydrogeologic and geochemical properties as well as the temporal variability were considered. Two scenarios represent alternative future behavior of the Columbia River adjacent to the site were considered. The scenario alternatives were implemented in the models through the boundary conditions. Results demonstrate the feasibility of applying a comprehensive uncertainty assessment to large-scale, detailed groundwater flow

  9. Use of GIS and 3D Modeling for Development and Conceptualization of a Performance Assessment Model for Decommissioning of a Complex Site

    SciTech Connect

    Esh, D. W.; Gross, A. J.; Thaggard, M.

    2006-07-01

    Geographic Information Systems (GIS) and 3D geo-spatial modeling were employed to facilitate development and conceptualization of a performance assessment (PA) model that will be used to evaluate the health impacts of residual radioactivity at a former nuclear materials processing facility site in New York. Previous operations have resulted in a number of different sources of radiological contamination that must be assessed during site decommissioning. A performance assessment model is being developed to estimate radiological dose to potential receptors through the simulation of the release and transport of radionuclides, and exposure to residual contamination for hundreds to thousands of years in the future. A variety of inputs are required to parameterize the performance assessment model, such as: distance from the waste to surface water bodies, thickness of geologic units for saturated transport, saturated thickness of the geologic units, and spatial and temporal average of percent of waste that is saturated. GIS and 3D modeling are used to analyze and abstract aleatory uncertainty associated with the dimensionality of the geologic system into epistemic uncertainty for one- and two-dimensional process models for flow and transport of radionuclides. Three-dimensional geo-spatial modeling was used to develop the geologic framework and the geometrical representation of the residual contamination within the geologic framework. GIS was used in the initial development and parameterization of the transport pathways, to provide spatial context to the PA model, and to link it to the 3D geologic framework and contamination geometry models. Both the GIS and 3-D modeling were used to interpret the results of runs of the PA model. (authors)

  10. Fuzzy conceptual rainfall runoff models

    NASA Astrophysics Data System (ADS)

    Özelkan, Ertunga C.; Duckstein, Lucien

    2001-11-01

    A fuzzy conceptual rainfall-runoff (CRR) framework is proposed herein to deal with those parameter uncertainties of conceptual rainfall-runoff models, that are related to data and/or model structure: with every element of the rainfall-runoff model assumed to be possibly uncertain, taken here as being fuzzy. First, the conceptual rainfall-runoff system is fuzzified and then different operational modes are formulated using fuzzy rules; second, the parameter identification aspect is examined using fuzzy regression techniques. In particular, bi-objective and tri-objective fuzzy regression models are applied in the case of linear conceptual rainfall-runoff models so that the decision maker may be able to trade off prediction vagueness (uncertainty) and the embedding outliers. For the non-linear models, a fuzzy least squares regression framework is applied to derive the model parameters. The methodology is illustrated using: (1) a linear conceptual rainfall-runoff model; (2) an experimental two-parameter model; and (3) a simplified version of the Sacramento soil moisture accounting model of the US National Weather Services river forecast system (SAC-SMA) known as the six-parameter model. It is shown that the fuzzy logic framework enables the decision maker to gain insight about the model sensitivity and the uncertainty stemming from the elements of the CRR model.

  11. Understanding the fate of polycyclic aromatic hydrocarbons at a forest fire site using a conceptual model based on field monitoring.

    PubMed

    Simon, Erwan; Choi, Sung-Deuk; Park, Min-Kyu

    2016-11-01

    Forest fires are a well-known source of polycyclic aromatic hydrocarbons (PAHs). After forest fires, residual ash above a soil layer can be highly contaminated with PAHs. However, little is known about the fate of these contaminants, particularly about their susceptibility to be transferred deeper into underlying soil or downstream during rainfall events. In this study, meteorological conditions, organic carbon (OC) content, and the 16 US-EPA priority PAHs in unburnt control soil, burnt soil, and ash were monitored for 16 months after a forest fire. Whereas the ash was significantly contaminated with PAHs, the levels of PAHs in the underlying burnt soil were similar to those of the control soil. In the ash bed, the levels of PAHs normalized by OC also decreased. Neither PAHs nor OC lost from the ash bed was substantially transferred to the underlying soil. Instead, significant amounts of PAHs in the ash bed were likely removed by surface runoff. Light PAHs were dominantly emitted from the forest fire, but they showed higher decreasing rates with total precipitation. These findings were explained by a conceptual model for the fate of PAHs, involving four distinct processes related to precipitation and two states of the ash bed. PMID:27368087

  12. Conceptual models of information processing

    NASA Technical Reports Server (NTRS)

    Stewart, L. J.

    1983-01-01

    The conceptual information processing issues are examined. Human information processing is defined as an active cognitive process that is analogous to a system. It is the flow and transformation of information within a human. The human is viewed as an active information seeker who is constantly receiving, processing, and acting upon the surrounding environmental stimuli. Human information processing models are conceptual representations of cognitive behaviors. Models of information processing are useful in representing the different theoretical positions and in attempting to define the limits and capabilities of human memory. It is concluded that an understanding of conceptual human information processing models and their applications to systems design leads to a better human factors approach.

  13. Model Breaking Points Conceptualized

    ERIC Educational Resources Information Center

    Vig, Rozy; Murray, Eileen; Star, Jon R.

    2014-01-01

    Current curriculum initiatives (e.g., National Governors Association Center for Best Practices and Council of Chief State School Officers 2010) advocate that models be used in the mathematics classroom. However, despite their apparent promise, there comes a point when models break, a point in the mathematical problem space where the model cannot,…

  14. Conceptual design report for site drainage control

    SciTech Connect

    Hunter, M.R.

    1996-07-01

    The Mound Plant (Mound), located in Miamisburg, Ohio, is a Department of Energy (DOE) development and production facility performing support work for DOE`s weapons and energy-related programs. EG&G Mound Applied Technologies, Inc. (EG&G) is the Operating Contractor (OC) for this Government-Owned, Contractor-Operated (GOCO) facility. The work performed at Mound emphasizes nuclear energy and explosives technology. Mound is currently implementing an Environmental, Safety & Health (ES&H) Upgrades Program designed to protect its employees, the public, and the environment from adverse effects caused by facility activities. The first project of this multiphase program is now in the final stages of construction, and the second project is currently under design. Four additional projects, one of which is presented in this report, are in the conceptual design stage. At Mound, 22 soil zones have become contaminated with radioactive material. These zones cover approximately 20 percent of the total area of developed property at the site. During a storm event, the rainwater washes contaminated soil from these zones into the storm sewer system. These radioactive contaminants may then be discharged along with the stormwater into the Great Miami River via the Miami Erie Canal. This conceptual design report (CDR), Site Drainage Control, the fourth project in the ES&H program, describes a project that will provide improvements and much needed repairs to inadequate and deteriorating portions of the storm drainage system on the developed property. The project also will provide a stormwater retention facility capable of storing the stormwater runoff, from the developed property, resulting from a 100-year storm event. These improvements will permit the effective control and monitoring of stormwater to prevent the spread of radioactive contaminants from contaminated soil zones and will provide a means to collect and contain accidental spills of hazardous substances.

  15. Contributing towards a conceptual model of soil-landscape co-evolution: observations from historic mining sites in Alberta, Canada

    NASA Astrophysics Data System (ADS)

    Raab, Thomas; Naeth, Anne; Hirsch, Florian; Raab, Alexandra

    2016-04-01

    characteristic geomorphology of the prairie can be found in landscape (i). Distinct differences are found in properties and types of soils in these four landscapes. Natural soils and pile soils characteristically differ in parent material and soil horizons. No information is gathered yet for the reclaimed soils and the landslides soils due to prohibited access. However, based on what we find at the former Diplomat Mine we can conclude that distribution, development and properties of unreclaimed soils in historical open cast mines in Alberta are primarily controlled by parent material and topography. The geomorphological set-up is dominating the trajectory of vegetation development and post-mining geomorphodynamics. Contrasting slope aspects determine micro climatic conditions and lead to different vegetation types. This has likely had an effect on soil development and soil properties (especially carbon stocks). Further studies will be conducted to quantify these differing soil properties to refine this conceptual model of initial pedogenesis and soil distribution on very young landforms in the prairie landscapes.

  16. Conceptual dynamical models for turbulence

    PubMed Central

    Majda, Andrew J.; Lee, Yoonsang

    2014-01-01

    Understanding the complexity of anisotropic turbulent processes in engineering and environmental fluid flows is a formidable challenge with practical significance because energy often flows intermittently from the smaller scales to impact the largest scales in these flows. Conceptual dynamical models for anisotropic turbulence are introduced and developed here which, despite their simplicity, capture key features of vastly more complicated turbulent systems. These conceptual models involve a large-scale mean flow and turbulent fluctuations on a variety of spatial scales with energy-conserving wave–mean-flow interactions as well as stochastic forcing of the fluctuations. Numerical experiments with a six-dimensional conceptual dynamical model confirm that these models capture key statistical features of vastly more complex anisotropic turbulent systems in a qualitative fashion. These features include chaotic statistical behavior of the mean flow with a sub-Gaussian probability distribution function (pdf) for its fluctuations whereas the turbulent fluctuations have decreasing energy and correlation times at smaller scales, with nearly Gaussian pdfs for the large-scale fluctuations and fat-tailed non-Gaussian pdfs for the smaller-scale fluctuations. This last feature is a manifestation of intermittency of the small-scale fluctuations where turbulent modes with small variance have relatively frequent extreme events which directly impact the mean flow. The dynamical models introduced here potentially provide a useful test bed for algorithms for prediction, uncertainty quantification, and data assimilation for anisotropic turbulent systems. PMID:24753605

  17. Conceptual dynamical models for turbulence.

    PubMed

    Majda, Andrew J; Lee, Yoonsang

    2014-05-01

    Understanding the complexity of anisotropic turbulent processes in engineering and environmental fluid flows is a formidable challenge with practical significance because energy often flows intermittently from the smaller scales to impact the largest scales in these flows. Conceptual dynamical models for anisotropic turbulence are introduced and developed here which, despite their simplicity, capture key features of vastly more complicated turbulent systems. These conceptual models involve a large-scale mean flow and turbulent fluctuations on a variety of spatial scales with energy-conserving wave-mean-flow interactions as well as stochastic forcing of the fluctuations. Numerical experiments with a six-dimensional conceptual dynamical model confirm that these models capture key statistical features of vastly more complex anisotropic turbulent systems in a qualitative fashion. These features include chaotic statistical behavior of the mean flow with a sub-Gaussian probability distribution function (pdf) for its fluctuations whereas the turbulent fluctuations have decreasing energy and correlation times at smaller scales, with nearly Gaussian pdfs for the large-scale fluctuations and fat-tailed non-Gaussian pdfs for the smaller-scale fluctuations. This last feature is a manifestation of intermittency of the small-scale fluctuations where turbulent modes with small variance have relatively frequent extreme events which directly impact the mean flow. The dynamical models introduced here potentially provide a useful test bed for algorithms for prediction, uncertainty quantification, and data assimilation for anisotropic turbulent systems. PMID:24753605

  18. Geohydrology and conceptual model of a ground-water-flow system near a Superfund site in Cheshire, Connecticut

    USGS Publications Warehouse

    Stone, J.R.; Barlow, P.M.; Starn, J.J.

    1996-01-01

    Degradation of ground-water quality has been identified in an area of the north-central part of the town of Cheshire, Connecticut. An investigation by the U.S. Geological Survey, in cooperation with the U.S. Environmental Protection Agency, was done during 1994-95 to characterize the unconsolidated glacial deposits and the sedimentary bedrock, integrate the local geohydrologic conditions with the regional geohydrologic system, and develop a conceptual understanding of ground-water flow in the study area. A regional ground-water-flow model developed for the region near the study area indicates that perennial streams, including Judd Brook and the Tenmile River, form hydrologic divides that separate the larger region into hydraulically independent flow systems. In the local study area, synoptic water-level measurements made in June 1995 indicate that ground water near the water table flows west and southwestward from the low hill on the eastern side of the area toward the pond and wetlands along Judd Brook. Water-level data indicate that there is good hydraulic connection between the unconsolidated materials and underlying fractured bedrock. Unconsolidated materials in the study area consist principally of glacial stratified deposits that are fine sand, silt, and clay of glaci- olacustrine origin; locally these overlie thin glacial till. The glacial sediments range in thickness from a few feet to about 25 ft in the eastern part of the study area and are as much as 100 ft thick in the western and southern part of the study area beneath the Judd Brook and Tenmile River valleys. Fluvial redbeds of the New Haven Arkose underlie the glacial deposits in the region; in the study area, the redbeds consist of (1) channel sandstone units, which are coarse sandstone to fine conglomerate, generally in 6- to 15-ft- thick sequences; and (2) overbank mudstone units, which are siltstone and silty sandstone with some fine sandstone, generally in 6- to 50-ft-thick sequences. Thin

  19. CONCEPTUAL MODELS FOR WATERSHED AND REGIONAL ASSESSMENTS

    EPA Science Inventory

    Conceptual models, as defined here, describe and illustrate the relationships between ecological receptors, the stressors to which they may be exposed, and the potential sources of the those stressors within a particular area or ecosystem. This document describes conceptual model...

  20. Research program to develop and validate conceptual models for flow and transport through unsaturated, fractured rock; Yucca Mountain Site Characterization Project

    SciTech Connect

    Glass, R.J.; Tidwell, V.C.

    1991-09-01

    As part of the Yucca Mountain Project, our research program to develop and validate conceptual models for flow and transport through unsaturated fractured rock integrates fundamental physical experimentation with conceptual model formulation and mathematical modeling. Our research is directed toward developing and validating macroscopic, continuum-based models and supporting effective property models because of their widespread utility within the context of this project. Success relative to the development and validation of effective property models is predicted on a firm understanding of the basic physics governing flow through fractured media, specifically in the areas of unsaturated flow and transport in a single fracture and fracture-matrix interaction.

  1. Conceptual Models for Search Engines

    NASA Astrophysics Data System (ADS)

    Hendry, D. G.; Efthimiadis, E. N.

    Search engines have entered popular culture. They touch people in diverse private and public settings and thus heighten the importance of such important social matters as information privacy and control, censorship, and equitable access. To fully benefit from search engines and to participate in debate about their merits, people necessarily appeal to their understandings for how they function. In this chapter we examine the conceptual understandings that people have of search engines by performing a content analysis on the sketches that 200 undergraduate and graduate students drew when asked to draw a sketch of how a search engine works. Analysis of the sketches reveals a diverse range of conceptual approaches, metaphors, representations, and misconceptions. On the whole, the conceptual models articulated by these students are simplistic. However, students with higher levels of academic achievement sketched more complete models. This research calls attention to the importance of improving students' technical knowledge of how search engines work so they can be better equipped to develop and advocate policies for how search engines should be embedded in, and restricted from, various private and public information settings.

  2. toolkit computational mesh conceptual model.

    SciTech Connect

    Baur, David G.; Edwards, Harold Carter; Cochran, William K.; Williams, Alan B.; Sjaardema, Gregory D.

    2010-03-01

    The Sierra Toolkit computational mesh is a software library intended to support massively parallel multi-physics computations on dynamically changing unstructured meshes. This domain of intended use is inherently complex due to distributed memory parallelism, parallel scalability, heterogeneity of physics, heterogeneous discretization of an unstructured mesh, and runtime adaptation of the mesh. Management of this inherent complexity begins with a conceptual analysis and modeling of this domain of intended use; i.e., development of a domain model. The Sierra Toolkit computational mesh software library is designed and implemented based upon this domain model. Software developers using, maintaining, or extending the Sierra Toolkit computational mesh library must be familiar with the concepts/domain model presented in this report.

  3. A conceptual model for site-level ecology of the giant gartersnake (Thamnophis gigas) in the Sacramento Valley, California

    USGS Publications Warehouse

    Halstead, Brian J.; Wylie, Glenn D.; Casazza, Michael L.; Hansen, Eric C.; Scherer, Rick D.; Patterson, Laura C.

    2015-01-01

    Bayesian networks further provide a clear visual display of the model that facilitates understanding among various stakeholders (Marcot and others, 2001; Uusitalo , 2007). Empirical data and expert judgment can be combined, as continuous or categorical variables, to update knowledge about the system (Marcot and others, 2001; Uusitalo , 2007). Importantly, Bayesian network models allow inference from causes to consequences, but also from consequences to causes, so that data can inform the states of nodes (values of different random variables) in either direction (Marcot and others, 2001; Uusitalo , 2007). Because they can incorporate both decision nodes that represent management actions and utility nodes that quantify the costs and benefits of outcomes, Bayesian networks are ideally suited to risk analysis and adaptive management (Nyberg and others, 2006; Howes and others, 2010). Thus, Bayesian network models are useful in situations where empirical data are not available, such as questions concerning the responses of giant gartersnakes to management.

  4. A Conceptual Data Model of Datum Systems

    PubMed Central

    McCaleb, Michael R.

    1999-01-01

    A new conceptual data model that addresses the geometric dimensioning and tolerancing concepts of datum systems, datums, datum features, datum targets, and the relationships among these concepts, is presented. Additionally, a portion of a related data model, Part 47 of STEP (ISO 10303-47), is reviewed and a comparison is made between it and the new conceptual data model.

  5. Conceptual and logical level of database modeling

    NASA Astrophysics Data System (ADS)

    Hunka, Frantisek; Matula, Jiri

    2016-06-01

    Conceptual and logical levels form the top most levels of database modeling. Usually, ORM (Object Role Modeling) and ER diagrams are utilized to capture the corresponding schema. The final aim of business process modeling is to store its results in the form of database solution. For this reason, value oriented business process modeling which utilizes ER diagram to express the modeling entities and relationships between them are used. However, ER diagrams form the logical level of database schema. To extend possibilities of different business process modeling methodologies, the conceptual level of database modeling is needed. The paper deals with the REA value modeling approach to business process modeling using ER-diagrams, and derives conceptual model utilizing ORM modeling approach. Conceptual model extends possibilities for value modeling to other business modeling approaches.

  6. Analysis of Hydrogeologic Conceptual Model and Parameter Uncertainty

    SciTech Connect

    Meyer, Philip D.; Nicholson, Thomas J.; Mishra, Srikanta

    2003-06-24

    A systematic methodology for assessing hydrogeologic conceptual model, parameter, and scenario uncertainties is being developed to support technical reviews of environmental assessments related to decommissioning of nuclear facilities. The first major task being undertaken is to produce a coupled parameter and conceptual model uncertainty assessment methodology. This task is based on previous studies that have primarily dealt individually with these two types of uncertainties. Conceptual model uncertainty analysis is based on the existence of alternative conceptual models that are generated using a set of clearly stated guidelines targeted at the needs of NRC staff. Parameter uncertainty analysis makes use of generic site characterization data as well as site-specific characterization and monitoring data to evaluate parameter uncertainty in each of the alternative conceptual models. Propagation of parameter uncertainty will be carried out through implementation of a general stochastic model of groundwater flow and transport in the saturated and unsaturated zones. Evaluation of prediction uncertainty will make use of Bayesian model averaging and visualization of model results. The goal of this study is to develop a practical tool to quantify uncertainties in the conceptual model and parameters identified in performance assessments.

  7. Conceptualization of a hypothetical high-level nuclear waste repository site in unsaturated, fractured tuff

    SciTech Connect

    Parsons, A.M.; Olague, N.E.; Gallegos, D.P.

    1991-01-01

    Under the sponsorship of the US Nuclear Regulatory Commission (NRC), Sandia National Laboratories (SNL) is developing a performance assessment methodology for the analysis of long-term disposal and isolation of high-level nuclear wastes (HLW) in alternative geologic media. As part of this exercise, SNL created a conceptualization of ground-water flow and radionuclide transport in the far field of a hypothetical HLW repository site located in unsaturated, fractured tuff formations. This study provides a foundation for the development of conceptual mathematical, and numerical models to be used in this performance assessment methodology. This conceptualization is site specific in terms of geometry, the regional ground-water flow system, stratigraphy, and structure in that these are based on information from Yucca Mountain located on the Nevada Test Site. However, in terms of processes in unsaturated, fractured, porous media, the model is generic. This report also provides a review and evaluation of previously proposed conceptual models of unsaturated and saturated flow and solute transport. This report provides a qualitative description of a hypothetical HLW repository site in fractured tuff. However, evaluation of the current knowledge of flow and transport at Yucca Mountain does not yield a single conceptual model. Instead, multiple conceptual models are possible given the existing information.

  8. Pu(V) transport through Savannah River Site soils - an evaluation of a conceptual model of surface- mediated reduction to Pu (IV).

    PubMed

    Powell, Brian A; Kaplan, Daniel I; Serkiz, Steven M; Coates, John T; Fjeld, Robert A

    2014-05-01

    Over the last fifteen years the Savannah River Site (SRS) in South Carolina, USA, was selected as the site of three new plutonium facilities: the Mixed Oxide Fuel Fabrication Facility, Pit Disassembly and Conversion Facility, and the Pu Immobilization Plant. In order to assess the potential human and environmental risk associated with these recent initiatives, improved understanding of the fate and transport of Pu in the SRS subsurface environment is necessary. The hypothesis of this study was that the more mobile forms of Pu, Pu(V) and Pu(VI), would be reduced to the less mobile Pu(III/IV) oxidation states under ambient SRS subsurface conditions. Laboratory-scale dynamic flow experiments (i.e., column studies) indicated that Pu(V) was very mobile in SRS sediments. At higher pH values the mobility of Pu decreased and the fraction of Pu that became irreversibly sorbed to the sediment increased, albeit, only slightly. Conversely, these column experiments showed that Pu(IV) was essentially immobile and was largely irreversibly sorbed to the sediment. More than 100 batch sorption experiments were also conducted with four end-member sediments, i.e., sediments that include the chemical, textural, and mineralogical properties likely to exist in the SRS. These tests were conducted as a function of initial Pu oxidation state, pH, and contact time and consistently demonstrated that although Pu(V) sorbed initially quite weakly to sediments, it slowly, over the course of <33 days, sorbed very strongly to sediments, to approximately the same degree as Pu(IV). This is consistent with our hypothesis that Pu(V) is reduced to the more strongly sorbing form of Pu, Pu(IV). These studies provide important experimental support for a conceptual geochemical model for dissolved Pu in a highly weathered subsurface environment. That is that, irrespective of the initial oxidation state of the dissolved Pu introduced into a SRS sediment system, Pu(IV) controls the environmental transport

  9. Identifiability analysis in conceptual sewer modelling.

    PubMed

    Kleidorfer, M; Leonhardt, G; Rauch, W

    2012-01-01

    For a sufficient calibration of an environmental model not only parameter sensitivity but also parameter identifiability is an important issue. In identifiability analysis it is possible to analyse whether changes in one parameter can be compensated by appropriate changes of the other ones within a given uncertainty range. Parameter identifiability is conditional to the information content of the calibration data and consequently conditional to a certain measurement layout (i.e. types of measurements, number and location of measurement sites, temporal resolution of measurements etc.). Hence the influence of number and location of measurement sites on the number of identifiable parameters can be investigated. In the present study identifiability analysis is applied to a conceptual model of a combined sewer system aiming to predict the combined sewer overflow emissions. Different measurement layouts are tested and it can be shown that only 13 of the most sensitive catchment areas (represented by the model parameter 'effective impervious area') can be identified when overflow measurements of the 20 highest overflows and the runoff to the waste water treatment plant are used for calibration. The main advantage of this method is very low computational costs as the number of required model runs equals the total number of model parameters. Hence, this method is a valuable tool when analysing large models with a long runtime and many parameters. PMID:22864432

  10. Guide for developing conceptual models for ecological risk assessments

    SciTech Connect

    Suter, G.W., II

    1996-05-01

    Ecological conceptual models are the result of the problem formulation phase of an ecological risk assessment, which is an important component of the Remedial Investigation process. They present hypotheses of how the site contaminants might affect the site ecology. The contaminant sources, routes, media, routes, and endpoint receptors are presented in the form of a flow chart. This guide is for preparing the conceptual models; use of this guide will standardize the models so that they will be of high quality, useful to the assessment process, and sufficiently consistent so that connections between sources of exposure and receptors can be extended across operable units (OU). Generic conceptual models are presented for source, aquatic integrator, groundwater integrator, and terrestrial OUs.

  11. Umatilla Satellite and Release Sites Project : Final Conceptual Design Report.

    SciTech Connect

    Montgomery, James M.

    1992-03-01

    This report presents the results of site analysis for the Umatilla Satellite and Release Sites Project. The purpose of this project is to provide engineering services for the siting and conceptual design of satellite and release facilities for the Umatilla Basin hatchery program. The Umatilla Basin hatchery program consists of artificial production facilities for salmon and steelhead to enhance production in the Umatilla River as defined in the Umatilla master plan approved in 1989 by the Northwest Power Planning Council. Facilities identified in the master plan include adult salmon broodstock holding and spawning facilities, facilities for recovery, acclimation, and/or extended rearing of salmon juveniles, and development of river sites for release of hatchery salmon and steelhead. The historic and current distribution of fall chinook, summer chinook, and coho salmon and steelhead trout was summarized for the Umatilla River basin. Current and future production and release objectives were reviewed. Twenty seven sites were evaluated for the potential development of facilities. Engineering and environmental attributes of the sites were evaluated and compared to facility requirements for water and space. Site screening was conducted to identify the sites with the most potential for facility development. Alternative sites were selected for conceptual design of each facility type. A proposed program for adult holding facilities, final rearing/acclimation, and direct release facilities was developed.

  12. Federal Facilities Compliance Act, Conceptual Site Treatment Plan. Part 1

    SciTech Connect

    1993-10-29

    This Conceptual Site Treatment Plan was prepared by Ames Laboratory to meet the requirements of the Federal Facilities Compliance Act. Topics discussed in this document include: general discussion of the plan, including the purpose and scope; technical aspects of preparing plans, including the rationale behind the treatability groupings and a discussion of characterization issues; treatment technology needs and treatment options for specific waste streams; low-level mixed waste options; TRU waste options; and future waste generation from restoration activities.

  13. Site Characterization Plan (SCP) conceptual design criteria document

    SciTech Connect

    Naiknimbalkar, N.M.

    1986-05-19

    This SCP Conceptual Design Criteria Document was developed to guide engineering effort for Engineering Study No. 10, the supporting document for Chapter 6 of the SCP. The document provides regulatory design guidance, design rationale derived from the Generic Requirements for a Mined Geological Disposal System document, site-specific criteria, and design assumptions. Appendices were added to provide additional information on geology and seals design. 24 figs., 15 tabs.

  14. SCP (Site Characterization Plan) conceptual design criteria document

    SciTech Connect

    Naiknimbalkar, N.M.

    1985-05-01

    This SCP Conceptual Design Criteria Document was developed to guide engineering efforts for Engineering Study No. 10, the supporting document for Chapter 6 of the SCP. The document provides regulatory design guidance, design rationale derived from the Generic Requirements for a Mined Geological Disposal System document, site-specific criteria, and design assumptions. Appendices were added to provide additional information on geology and seals design.

  15. Formalizing Linguistic Conventions for Conceptual Models

    NASA Astrophysics Data System (ADS)

    Becker, Jörg; Delfmann, Patrick; Herwig, Sebastian; Lis, Łukasz; Stein, Armin

    A precondition for the appropriate analysis of conceptual models is not only their syntactic correctness but also their semantic comparability. Assuring comparability is challenging especially when models are developed by different persons. Empirical studies show that such models can vary heavily, especially in model element naming, even if they express the same issue. In contrast to most ontology-driven approaches proposing the resolution of these differences ex-post, we introduce an approach that avoids naming differences in conceptual models already during modeling. Therefore we formalize naming conventions combining domain thesauri and phrase structures based on a lin-guistic grammar. This allows for guiding modelers automatically during the modeling process using standardized labels for model elements. Our approach is generic, making it applicable for any modeling language.

  16. Modeling field-scale multiple tracer injection at a low-level waste disposal site in fractured rocks: effect of multiscale heterogeneity and source term uncertainty on conceptual understanding of mass transfer processes.

    PubMed

    Gwo, Jin-Ping; Jardine, Philip M; Sanford, William E

    2005-03-01

    Multiple factors may affect the scale-up of laboratory multi-tracer injection into structured porous media to the field. Under transient flow conditions and with multiscale heterogeneities in the field, previous attempts to scale-up laboratory experiments have not answered definitely the questions about the governing mechanisms and the spatial extent of the influence of small-scale mass transfer processes such as matrix diffusion. The objective of this research is to investigate the effects of multiscale heterogeneity, mechanistic and site model conceptualization, and source term density effect on elucidating and interpreting tracer movement in the field. Tracer release and monitoring information previously obtained in a field campaign of multiple, conservative tracer injection under natural hydraulic gradients at a low-level waste disposal site in eastern Tennessee, United States, is used for the research. A suite of two-pore-domain, or fracture-matrix, groundwater flow and transport models are calibrated and used to conduct model parameter and prediction uncertainty analyses. These efforts are facilitated by a novel nested Latin-hypercube sampling technique. Our results verify, at field scale, a multiple-pore-domain, multiscale mechanistic conceptual model that was used previously to interpret only laboratory observations. The results also suggest that, integrated over the entire field site, mass flux rates attributable to small-scale mass transfer are comparable to that of field-scale solute transport. The uncertainty analyses show that fracture spacing is the most important model parameter and model prediction uncertainty is relatively higher at the interface between the preferred flow path and its parent bedrock. The comparisons of site conceptual models indicate that the effect of matrix diffusion may be confined to the immediate neighborhood of the preferential flow path. Finally, because the relatively large amount of tracer needed for field studies, it is

  17. Leading Generative Groups: A Conceptual Model

    ERIC Educational Resources Information Center

    London, Manuel; Sobel-Lojeski, Karen A.; Reilly, Richard R.

    2012-01-01

    This article presents a conceptual model of leadership in generative groups. Generative groups have diverse team members who are expected to develop innovative solutions to complex, unstructured problems. The challenge for leaders of generative groups is to balance (a) establishing shared goals with recognizing members' vested interests, (b)…

  18. Self-Presentation: A Conceptualization and Model.

    ERIC Educational Resources Information Center

    Schlenker, Barry R.

    This paper provides a conceptual definition and model of self-presentational behavior. Self-presentation is defined as the attempt to control self-relevant images before real or imagined others. Several aspects of the definition are discussed along with the notion that people's self-presentations represent the choice of the most desirable images…

  19. A Conceptual Model of Rhetorical Community.

    ERIC Educational Resources Information Center

    Ehrenhaus, Peter

    A conceptual model of the rhetorical community that addresses the sociodramatic processes through which social order evolves, is maintained, can change, and is threatened is presented in this paper. Following an introduction, the paper identifies the various uses of rhetorical vision and rhetorical community that are found in fantasy theme…

  20. Administrator Training and Development: Conceptual Model.

    ERIC Educational Resources Information Center

    Boardman, Gerald R.

    A conceptual model for an individualized training program for school administrators integrates processes, characteristics, and tasks through theory training and application. Based on an application of contingency theory, it provides a system matching up administrative candidates' needs in three areas (administrative process, administrative…

  1. Conceptual Models of Frontal Cyclones.

    ERIC Educational Resources Information Center

    Eagleman, Joe R.

    1981-01-01

    This discussion of weather models uses maps to illustrate the differences among three types of frontal cyclones (long wave, short wave, and troughs). Awareness of these cyclones can provide clues to atmospheric conditions which can lead toward accurate weather forecasting. (AM)

  2. A conceptual model for megaprogramming

    NASA Technical Reports Server (NTRS)

    Tracz, Will

    1990-01-01

    Megaprogramming is component-based software engineering and life-cycle management. Magaprogramming and its relationship to other research initiatives (common prototyping system/common prototyping language, domain specific software architectures, and software understanding) are analyzed. The desirable attributes of megaprogramming software components are identified and a software development model and resulting prototype megaprogramming system (library interconnection language extended by annotated Ada) are described.

  3. The conceptualization model problem—surprise

    NASA Astrophysics Data System (ADS)

    Bredehoeft, John

    2005-03-01

    The foundation of model analysis is the conceptual model. Surprise is defined as new data that renders the prevailing conceptual model invalid; as defined here it represents a paradigm shift. Limited empirical data indicate that surprises occur in 20-30% of model analyses. These data suggest that groundwater analysts have difficulty selecting the appropriate conceptual model. There is no ready remedy to the conceptual model problem other than (1) to collect as much data as is feasible, using all applicable methods—a complementary data collection methodology can lead to new information that changes the prevailing conceptual model, and (2) for the analyst to remain open to the fact that the conceptual model can change dramatically as more information is collected. In the final analysis, the hydrogeologist makes a subjective decision on the appropriate conceptual model. The conceptualization problem does not render models unusable. The problem introduces an uncertainty that often is not widely recognized. Conceptual model uncertainty is exacerbated in making long-term predictions of system performance. C'est le modèle conceptuel qui se trouve à base d'une analyse sur un modèle. On considère comme une surprise lorsque le modèle est invalidé par des données nouvelles; dans les termes définis ici la surprise est équivalente à un change de paradigme. Des données empiriques limitées indiquent que les surprises apparaissent dans 20 à 30% des analyses effectuées sur les modèles. Ces données suggèrent que l'analyse des eaux souterraines présente des difficultés lorsqu'il s'agit de choisir le modèle conceptuel approprié. Il n'existe pas un autre remède au problème du modèle conceptuel que: (1) rassembler autant des données que possible en utilisant toutes les méthodes applicables—la méthode des données complémentaires peut conduire aux nouvelles informations qui vont changer le modèle conceptuel, et (2) l'analyste doit rester ouvert au fait

  4. Carbon Tetrachloride Flow and Transport in the Subsurface of the 216-Z-18 Crib and 216-Z-1A Tile Field at the Hanford Site: Multifluid Flow Simulations and Conceptual Model Update

    SciTech Connect

    Oostrom, Mart; Rockhold, Mark L.; Thorne, Paul D.; Last, George V.; Truex, Michael J.

    2006-10-31

    Carbon tetrachloride (CT) was discharged to the 216-Z-9, Z-1A, and Z-18 waste sites that are included in the 200-PW-1 Operable Unit in Hanford 200 West Area. Fluor Hanford, Inc. is conducting a Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) remedial investigation/feasibility study (RI/FS) for the 200-PW-1 Operable Unit. As part of this overall effort, Pacific Northwest National Laboratory (PNNL) was contracted to improve the conceptual model of how CT is distributed in the Hanford 200 West Area subsurface through use of numerical flow and transport modeling. This work supports the U.S. Department of Energy's (DOE's) efforts to characterize the nature and distribution of CT in the 200 West Area and subsequently select an appropriate final remedy.

  5. A Conceptual Model of Learning Networks

    NASA Astrophysics Data System (ADS)

    Koper, Rob

    In the TENCompetence project a set of UML models (Booch et al. 1999) have been developed to specify the core concepts for Learning Networks Services that support professional competence development. The three most important, high-level models are (a) the use case model, (b) the conceptual model, and (c) the domain model. The first model identifies the primary use cases we need in order to support professional competence development. The second model describes the concept of competence and competence development from a theoretical point of view. What is a competence? How does it relate to the cognitive system of an actor? How are competences developed? The third model is a UML Domain Model that defines, among other things, the components of a Learning Network, defines the concepts and relationships between the concepts in a Learning Network and provides a starting point for the design of the overall architecture for Learning Network Services, including the data model.

  6. A contemporary conceptual model of hypochondriasis.

    PubMed

    Abramowitz, Jonathan S; Schwartz, Stefanie A; Whiteside, Stephen P

    2002-12-01

    Hypochondriasis (HC), which involves preoccupation with the fear of having a serious illness despite appropriate medical examination, is often encountered in medical settings. The most conspicuous feature of this disorder is seeking excessive reassurance from physicians, medical references, or self-inspection; however, many patients also fear they will receive upsetting information if evaluated and thus avoid consultations and remain preoccupied with physiologic events, believing they are physically ill. Thus, HC causes personal suffering for the patient and practical and cost management problems for professionals across fields of clinical practice. The past 2 decades have seen considerable improvement in the understanding and treatment of HC. In this article, we review a contemporary conceptual model of HC and an effective form of treatment called cognitive-behavioral therapy that is derived from this model. Recommendations for presenting this conceptualization to patients and encouraging proper treatment are also discussed. PMID:12479520

  7. Assessment of effectiveness of geologic isolation systems. A conceptual simulation model for release scenario analysis of a hypothetical site in Columbia Plateau Basalts

    SciTech Connect

    Stottlemyre, J.A.; Petrie, G.M.; Benson, G.L.; Zellmer, J.T.

    1981-01-01

    This report is a status report for an evolving methodology for release scenario development for underground nuclear waste repositories. As such, it is intended for use as a reference point and a preliminary description of an evolving geoscience methodology. When completed this methodology will be used as a tool in developing disruptive release scenarios for analyzing the long-term safety of geological nuclear waste repositories. While a basalt environment is used as an example, this report is not intended to reflect an actual site safety assessment for a repository in a media. It is rather intended to present a methodology system framework and to provide discussions of the geological phenomena and parameters that must be addressed in order to develop a methodology for potential release scenarios. It is also important to note that the phenomena, their interrelationships, and their relative importance along with the overall current structure of the model will change as new geological information is gathered through additional peer review, geotechnical input, site specific field work, and related research efforts.

  8. Use of Numerical Groundwater Modeling to Evaluate Uncertainty in Conceptual Models of Recharge and Hydrostratigraphy

    SciTech Connect

    Pohlmann, Karl; Ye, Ming; Pohll, Greg; Chapman, Jenny

    2007-01-19

    Numerical groundwater models are based on conceptualizations of hydrogeologic systems that are by necessity developed from limited information and therefore are simplifications of real conditions. Each aspect (e.g. recharge, hydrostratigraphy, boundary conditions) of the groundwater model is often based on a single conceptual model that is considered to be the best representation given the available data. However, the very nature of their construction means that each conceptual model is inherently uncertain and the available information may be insufficient to refute plausible alternatives, thereby raising the possibility that the flow model is underestimating overall uncertainty. In this study we use the Death Valley Regional Flow System model developed by the U.S. Geological Survey as a framework to predict regional groundwater flow southward into Yucca Flat on the Nevada Test Site. An important aspect of our work is to evaluate the uncertainty associated with multiple conceptual models of groundwater recharge and subsurface hydrostratigraphy and quantify the impacts of this uncertainty on model predictions. In our study, conceptual model uncertainty arises from two sources: (1) alternative interpretations of the hydrostratigraphy in the northern portion of Yucca Flat where, owing to sparse data, the hydrogeologic system can be conceptualized in different ways, and (2) uncertainty in groundwater recharge in the region as evidenced by the existence of several independent approaches for estimating this aspect of the hydrologic system. The composite prediction of groundwater flow is derived from the regional model that formally incorporates the uncertainty in these alternative input models using the maximum likelihood Bayesian model averaging method. An assessment of the joint predictive uncertainty of the input conceptual models is also produced. During this process, predictions of the alternative models are weighted by model probability, which is the degree of

  9. Optimal combinations of specialized conceptual hydrological models

    NASA Astrophysics Data System (ADS)

    Kayastha, Nagendra; Lal Shrestha, Durga; Solomatine, Dimitri

    2010-05-01

    In hydrological modelling it is a usual practice to use a single lumped conceptual model for hydrological simulations at all regimes. However often the simplicity of the modelling paradigm leads to errors in represent all the complexity of the physical processes in the catchment. A solution could be to model various hydrological processes separately by differently parameterized models, and to combine them. Different hydrological models have varying performance in reproducing catchment response. Generally it cannot be represented precisely in different segments of the hydrograph: some models performed well in simulating the peak flows, while others do well in capturing the low flows. Better performance can be achieved if a model being applied to the catchment using different model parameters that are calibrated using criteria favoring high or low flows. In this work we use a modular approach to simulate hydrology of a catchment, wherein multiple models are applied to replicate the catchment responses and each "specialist" model is calibrated according to a specific objective function which is chosen in a way that forces the model to capture certain aspects of the hydrograph, and outputs of models are combined using so-called "fuzzy committee". Such multi-model approach has been already previously implemented in the development of data driven and conceptual models (Fenicia et al., 2007), but its perfomance was considered only during the calibration period. In this study we tested an application to conceptual models in both calibration and verification period. In addition, we tested the sensitivity of the result to the use of different weightings used in the objective functions formulations, and memberbship functions used in the committee. The study was carried out for Bagamati catchment in Nepal and Brue catchment in United Kingdoms with the MATLAB-based implementation of HBV model. Multi-objective evolutionary optimization genetic algorithm (Deb, 2001) was used to

  10. Assessment of Alternative Conceptual Models Using Reactive Transport Modeling with Monitoring Data

    NASA Astrophysics Data System (ADS)

    Dai, Z.; Price, V.; Heffner, D.; Hodges, R.; Temples, T.; Nicholson, T.

    2005-12-01

    Monitoring data proved very useful in evaluating alternative conceptual models, simulating contaminant transport behavior, and reducing uncertainty. A graded approach using three alternative conceptual site models was formulated to simulate a field case of tetrachloroethene (PCE) transport and biodegradation. These models ranged from simple to complex in their representation of subsurface heterogeneities. The simplest model was a single-layer homogeneous aquifer that employed an analytical reactive transport code, BIOCHLOR (Aziz et al., 1999). Due to over-simplification of the aquifer structure, this simulation could not reproduce the monitoring data. The second model consisted of a multi-layer conceptual model, in combination with numerical modules, MODFLOW and RT3D within GMS, to simulate flow and reactive transport. Although the simulation results from the second model were comparatively better than those from the simple model, they still did not adequately reproduce the monitoring well concentrations because the geological structures were still inadequately defined. Finally, a more realistic conceptual model was formulated that incorporated heterogeneities and geologic structures identified from well logs and seismic survey data using the Petra and PetraSeis software. This conceptual model included both a major channel and a younger channel that were detected in the PCE source area. In this model, these channels control the local ground-water flow direction and provide a preferential chemical transport pathway. Simulation results using this conceptual site model proved compatible with the monitoring concentration data. This study demonstrates that the bias and uncertainty from inadequate conceptual models are much larger than those introduced from an inadequate choice of model parameter values (Neuman and Wierenga, 2003; Meyer et al., 2004; Ye et al., 2004). This case study integrated conceptual and numerical models, based on interpreted local hydrogeologic and

  11. Conceptual models for cumulative risk assessment.

    PubMed

    Linder, Stephen H; Sexton, Ken

    2011-12-01

    In the absence of scientific consensus on an appropriate theoretical framework, cumulative risk assessment and related research have relied on speculative conceptual models. We argue for the importance of theoretical backing for such models and discuss 3 relevant theoretical frameworks, each supporting a distinctive "family" of models. Social determinant models postulate that unequal health outcomes are caused by structural inequalities; health disparity models envision social and contextual factors acting through individual behaviors and biological mechanisms; and multiple stressor models incorporate environmental agents, emphasizing the intermediary role of these and other stressors. The conclusion is that more careful reliance on established frameworks will lead directly to improvements in characterizing cumulative risk burdens and accounting for disproportionate adverse health effects. PMID:22021317

  12. Conceptual Frameworks in the Doctoral Research Process: A Pedagogical Model

    ERIC Educational Resources Information Center

    Berman, Jeanette; Smyth, Robyn

    2015-01-01

    This paper contributes to consideration of the role of conceptual frameworks in the doctoral research process. Through reflection on the two authors' own conceptual frameworks for their doctoral studies, a pedagogical model has been developed. The model posits the development of a conceptual framework as a core element of the doctoral…

  13. A Structural Equation Model of Conceptual Change in Physics

    ERIC Educational Resources Information Center

    Taasoobshirazi, Gita; Sinatra, Gale M.

    2011-01-01

    A model of conceptual change in physics was tested on introductory-level, college physics students. Structural equation modeling was used to test hypothesized relationships among variables linked to conceptual change in physics including an approach goal orientation, need for cognition, motivation, and course grade. Conceptual change in physics…

  14. A Conceptual Model of Referee Efficacy

    PubMed Central

    Guillén, Félix; Feltz, Deborah L.

    2010-01-01

    This paper presents a conceptual model of referee efficacy, defines the concept, proposes sources of referee specific efficacy information, and suggests consequences of having high or low referee efficacy. Referee efficacy is defined as the extent to which referees believe they have the capacity to perform successfully in their job. Referee efficacy beliefs are hypothesized to be influenced by mastery experiences, referee knowledge/education, support from significant others, physical/mental preparedness, environmental comfort, and perceived anxiety. In turn, referee efficacy beliefs are hypothesized to influence referee performance, referee stress, athlete rule violations, athlete satisfaction, and co-referee satisfaction. PMID:21713174

  15. Facet Modelling: An Approach to Flexible and Integrated Conceptual Modelling.

    ERIC Educational Resources Information Center

    Opdahl, Andreas L.; Sindre, Guttorm

    1997-01-01

    Identifies weaknesses of conceptual modelling languages for the problem domain of information systems (IS) development. Outlines an approach called facet modelling of real-world problem domains to deal with the complexity of contemporary analysis problems. Shows how facet models can be defined and visualized; discusses facet modelling in relation…

  16. Propulsion System Models for Rotorcraft Conceptual Design

    NASA Technical Reports Server (NTRS)

    Johnson, Wayne

    2014-01-01

    The conceptual design code NDARC (NASA Design and Analysis of Rotorcraft) was initially implemented to model conventional rotorcraft propulsion systems, consisting of turboshaft engines burning jet fuel, connected to one or more rotors through a mechanical transmission. The NDARC propulsion system representation has been extended to cover additional propulsion concepts, including electric motors and generators, rotor reaction drive, turbojet and turbofan engines, fuel cells and solar cells, batteries, and fuel (energy) used without weight change. The paper describes these propulsion system components, the architecture of their implementation in NDARC, and the form of the models for performance and weight. Requirements are defined for improved performance and weight models of the new propulsion system components. With these new propulsion models, NDARC can be used to develop environmentally-friendly rotorcraft designs.

  17. Combined Estimation of Hydrogeologic Conceptual Model and Parameter Uncertainty

    SciTech Connect

    Meyer, Philip D.; Ye, Ming; Neuman, Shlomo P.; Cantrell, Kirk J.

    2004-03-01

    The objective of the research described in this report is the development and application of a methodology for comprehensively assessing the hydrogeologic uncertainties involved in dose assessment, including uncertainties associated with conceptual models, parameters, and scenarios. This report describes and applies a statistical method to quantitatively estimate the combined uncertainty in model predictions arising from conceptual model and parameter uncertainties. The method relies on model averaging to combine the predictions of a set of alternative models. Implementation is driven by the available data. When there is minimal site-specific data the method can be carried out with prior parameter estimates based on generic data and subjective prior model probabilities. For sites with observations of system behavior (and optionally data characterizing model parameters), the method uses model calibration to update the prior parameter estimates and model probabilities based on the correspondence between model predictions and site observations. The set of model alternatives can contain both simplified and complex models, with the requirement that all models be based on the same set of data. The method was applied to the geostatistical modeling of air permeability at a fractured rock site. Seven alternative variogram models of log air permeability were considered to represent data from single-hole pneumatic injection tests in six boreholes at the site. Unbiased maximum likelihood estimates of variogram and drift parameters were obtained for each model. Standard information criteria provided an ambiguous ranking of the models, which would not justify selecting one of them and discarding all others as is commonly done in practice. Instead, some of the models were eliminated based on their negligibly small updated probabilities and the rest were used to project the measured log permeabilities by kriging onto a rock volume containing the six boreholes. These four

  18. Conceptual classification model for Sustainable Flood Retention Basins.

    PubMed

    Scholz, Miklas; Sadowski, Adam J

    2009-01-01

    The aim of this paper is to recommend a rapid conceptual classification model for Sustainable Flood Retention Basins (SFRB) used to control runoff in a temperate climate. An SFRB is an aesthetically pleasing retention basin predominantly used for flood protection adhering to sustainable drainage and best management practices. The classification model was developed on the basis of a database of 141 SFRB using the River Rhine catchment in Baden (part of Baden-Württemberg, Germany) as a case study. It is based on an agglomerative cluster analysis and is intended to be used by engineers and scientists to adequately classify the following different types of SFRB: Hydraulic Flood Retention Basin, Traditional Flood Retention Basin, Sustainable Flood Retention Wetland, Aesthetic Flood Retention Wetland, Integrated Flood Retention Wetland and Natural Flood Retention Wetland. The selection of classification variables was supported by a principal component analysis. The identification of SFRB in the data set was based on a Ward cluster analysis of 34 weighted classification variables. Scoring tables were defined to enable the assignment of the six SFRB definitions to retention basins in the data set. The efficiency of these tables was based on a scoring system which gave the conceptual model for the example case study sites an overall efficiency of approximately 60% (as opposed to 17% by chance). This conceptual classification model should be utilized to improve communication by providing definitions for SFRB types. The classification definitions are likely to be applicable for other regions with both temperate oceanic and temperate continental climates. PMID:18280029

  19. CONCEPTUAL MODELS FOR THE LASSEN HYDROTHERMAL SYSTEM.

    USGS Publications Warehouse

    Ingebritsen, S.E.; Sorey, M.L.

    1987-01-01

    The Lassen hydrothermal system, like a number of other systems in regions of moderate to great topographic relief, includes steam-heated features at higher elevations and high-chloride springs at lower elevations, connected to and fed by a single circulation system at depth. Two conceptual models for such systems are presented. They are similar in several ways: however, there are basic differences in terms of the nature and extent of vapor-dominated conditions beneath the steam-heated features. For some Lassen-like systems, these differences could have environmental and economic implications. Available data do not make it possible to establish a single preferred model for the Lassen system, and the actual system is complex enough that both models may apply to different parts of the system.

  20. A conceptual holding model for veterinary applications.

    PubMed

    Ferrè, Nicola; Kuhn, Werner; Rumor, Massimo; Marangon, Stefano

    2014-05-01

    Spatial references are required when geographical information systems (GIS) are used for the collection, storage and management of data. In the veterinary domain, the spatial component of a holding (of animals) is usually defined by coordinates, and no other relevant information needs to be interpreted or used for manipulation of the data in the GIS environment provided. Users trying to integrate or reuse spatial data organised in such a way, frequently face the problem of data incompatibility and inconsistency. The root of the problem lies in differences with respect to syntax as well as variations in the semantic, spatial and temporal representations of the geographic features. To overcome these problems and to facilitate the inter-operability of different GIS, spatial data must be defined according to a \\"schema\\" that includes the definition, acquisition, analysis, access, presentation and transfer of such data between different users and systems. We propose an application \\"schema\\" of holdings for GIS applications in the veterinary domain according to the European directive framework (directive 2007/2/EC--INSPIRE). The conceptual model put forward has been developed at two specific levels to produce the essential and the abstract model, respectively. The former establishes the conceptual linkage of the system design to the real world, while the latter describes how the system or software works. The result is an application \\"schema\\" that formalises and unifies the information-theoretic foundations of how to spatially represent a holding in order to ensure straightforward information-sharing within the veterinary community. PMID:24893036

  1. Data Modeling & the Infrastructural Nature of Conceptual Tools

    ERIC Educational Resources Information Center

    Lesh, Richard; Caylor, Elizabeth; Gupta, Shweta

    2007-01-01

    The goal of this paper is to demonstrate the infrastructural nature of many modern conceptual technologies. The focus of this paper is on conceptual tools associated with elementary types of data modeling. We intend to show a variety of ways in which these conceptual tools not only express thinking, but also mold and shape thinking. And those ways…

  2. Detecting hydrological changes through conceptual model

    NASA Astrophysics Data System (ADS)

    Viola, Francesco; Caracciolo, Domenico; Pumo, Dario; Francipane, Antonio; Valerio Noto, Leonardo

    2015-04-01

    Natural changes and human modifications in hydrological systems coevolve and interact in a coupled and interlinked way. If, on one hand, climatic changes are stochastic, non-steady, and affect the hydrological systems, on the other hand, human-induced changes due to over-exploitation of soils and water resources modifies the natural landscape, water fluxes and its partitioning. Indeed, the traditional assumption of static systems in hydrological analysis, which has been adopted for long time, fails whenever transient climatic conditions and/or land use changes occur. Time series analysis is a way to explore environmental changes together with societal changes; unfortunately, the not distinguishability between causes restrict the scope of this method. In order to overcome this limitation, it is possible to couple time series analysis with an opportune hydrological model, such as a conceptual hydrological model, which offers a schematization of complex dynamics acting within a basin. Assuming that model parameters represent morphological basin characteristics and that calibration is a way to detect hydrological signature at a specific moment, it is possible to argue that calibrating the model over different time windows could be a method for detecting potential hydrological changes. In order to test the capabilities of a conceptual model in detecting hydrological changes, this work presents different "in silico" experiments. A synthetic-basin is forced with an ensemble of possible future scenarios generated with a stochastic weather generator able to simulate steady and non-steady climatic conditions. The experiments refer to Mediterranean climate, which is characterized by marked seasonality, and consider the outcomes of the IPCC 5th report for describing climate evolution in the next century. In particular, in order to generate future climate change scenarios, a stochastic downscaling in space and time is carried out using realizations of an ensemble of General

  3. Turnaround Time Modeling for Conceptual Rocket Engines

    NASA Technical Reports Server (NTRS)

    Nix, Michael; Staton, Eric J.

    2004-01-01

    Recent years have brought about a paradigm shift within NASA and the Space Launch Community regarding the performance of conceptual design. Reliability, maintainability, supportability, and operability are no longer effects of design; they have moved to the forefront and are affecting design. A primary focus of this shift has been a planned decrease in vehicle turnaround time. Potentials for instituting this decrease include attacking the issues of removing, refurbishing, and replacing the engines after each flight. less, it is important to understand the operational affects of an engine on turnaround time, ground support personnel and equipment. One tool for visualizing this relationship involves the creation of a Discrete Event Simulation (DES). A DES model can be used to run a series of trade studies to determine if the engine is meeting its requirements, and, if not, what can be altered to bring it into compliance. Using DES, it is possible to look at the ways in which labor requirements, parallel maintenance versus serial maintenance, and maintenance scheduling affect the overall turnaround time. A detailed DES model of the Space Shuttle Main Engines (SSME) has been developed. Trades may be performed using the SSME Processing Model to see where maintenance bottlenecks occur, what the benefits (if any) are of increasing the numbers of personnel, or the number and location of facilities, in addition to trades previously mentioned, all with the goal of optimizing the operational turnaround time and minimizing operational cost. The SSME Processing Model was developed in such a way that it can easily be used as a foundation for developing DES models of other operational or developmental reusable engines. Performing a DES on a developmental engine during the conceptual phase makes it easier to affect the design and make changes to bring about a decrease in turnaround time and costs.

  4. Evaluation of conceptual, mathematical and physical-and-chemical models for describing subsurface radionuclide transport at the Lake Karachai Waste Disposal Site

    SciTech Connect

    Rumynin, V.G.; Mironenko, V.A.; Sindalovsky, L.N.; Boronina, A.V.; Konosavsky, P.K.; Pozdniakov, S.P.

    1998-06-01

    The goal of this work was to develop the methodology and to improve understanding of subsurface radionuclide transport for application to the Lake Karachai Site and to identify the influence of the processes and interactions involved into transport and fate of the radionuclides. The report is focused on two sets of problems, which have to do both with, hydrodynamic and hydrogeochemical aspects of the contaminant transport.

  5. Dynamic Multicriteria Evaluation of Conceptual Hydrological Models

    NASA Astrophysics Data System (ADS)

    de Vos, N. J.; Rientjes, T. H.; Fenicia, F.; Gupta, H. V.

    2007-12-01

    Accurate and precise forecasts of river streamflows are crucial for successful management of water resources and under the threat of hydrological extremes such as floods and droughts. Conceptual rainfall-runoff models are the most popular approach in flood forecasting. However, the calibration and evaluation of such models is often oversimplified by the use of performance statistics that largely ignore the dynamic character of a watershed system. This research aims to find novel ways of model evaluation by identifying periods of hydrologic similarity and customizing evaluation within each period using multiple criteria. A dynamic approach to hydrologic model identification, calibration and testing can be realized by applying clustering algorithms (e.g., Self-Organizing Map, Fuzzy C-means algorithm) to hydrological data. These algorithms are able to identify clusters in the data that represent periods of hydrological similarity. In this way, dynamic catchment system behavior can be simplified within the clusters that are identified. Although clustering requires a number of subjective choices, new insights into the hydrological functioning of a catchment can be obtained. Finally, separate model multi-criteria calibration and evaluation is performed for each of the clusters. Such a model evaluation procedure shows to be reliable and gives much-needed feedback on exactly where certain model structures fail. Several clustering algorithms were tested on two data sets of meso-scale and large-scale catchments. The results show that the clustering algorithms define categories that reflect hydrological process understanding: dry/wet seasons, rising/falling hydrograph limbs, precipitation-driven/ non-driven periods, etc. The results of various clustering algorithms are compared and validated using expert knowledge. Calibration results on a conceptual hydrological model show that the common practice of single-criteria calibration over the complete time series fails to perform

  6. Updated Conceptual Model for the 300 Area Uranium Groundwater Plume

    SciTech Connect

    Zachara, John M.; Freshley, Mark D.; Last, George V.; Peterson, Robert E.; Bjornstad, Bruce N.

    2012-11-01

    The 300 Area uranium groundwater plume in the 300-FF-5 Operable Unit is residual from past discharge of nuclear fuel fabrication wastes to a number of liquid (and solid) disposal sites. The source zones in the disposal sites were remediated by excavation and backfilled to grade, but sorbed uranium remains in deeper, unexcavated vadose zone sediments. In spite of source term removal, the groundwater plume has shown remarkable persistence, with concentrations exceeding the drinking water standard over an area of approximately 1 km2. The plume resides within a coupled vadose zone, groundwater, river zone system of immense complexity and scale. Interactions between geologic structure, the hydrologic system driven by the Columbia River, groundwater-river exchange points, and the geochemistry of uranium contribute to persistence of the plume. The U.S. Department of Energy (DOE) recently completed a Remedial Investigation/Feasibility Study (RI/FS) to document characterization of the 300 Area uranium plume and plan for beginning to implement proposed remedial actions. As part of the RI/FS document, a conceptual model was developed that integrates knowledge of the hydrogeologic and geochemical properties of the 300 Area and controlling processes to yield an understanding of how the system behaves and the variables that control it. Recent results from the Hanford Integrated Field Research Challenge site and the Subsurface Biogeochemistry Scientific Focus Area Project funded by the DOE Office of Science were used to update the conceptual model and provide an assessment of key factors controlling plume persistence.

  7. A conceptual model of intentional comfort touch.

    PubMed

    Connor, Ann; Howett, Maeve

    2009-06-01

    This article discusses the application and integration of intentional comfort touch as a holistic nursing practice. A review of the literature on touch and its related concepts is included. Although nurses use touch frequently in patient encounters, it is not always used intentionally or deliberately to enhance care. The article compares and contrasts intentional comfort touch with nonintentional or procedural touch. The use of intentional comfort touch in innovative clinical settings with diverse and at-risk populations is described. Based on clinical experiences and the current literature, a conceptual model of intentional comfort touch is proposed. The application of touch is discussed as is the meaning and importance of intentional touch for students, faculty, and patients. PMID:19443699

  8. Stormwater infiltration trenches: a conceptual modelling approach.

    PubMed

    Freni, Gabriele; Mannina, Giorgio; Viviani, Gaspare

    2009-01-01

    In recent years, limitations linked to traditional urban drainage schemes have been pointed out and new approaches are developing introducing more natural methods for retaining and/or disposing of stormwater. These mitigation measures are generally called Best Management Practices or Sustainable Urban Drainage System and they include practices such as infiltration and storage tanks in order to reduce the peak flow and retain part of the polluting components. The introduction of such practices in urban drainage systems entails an upgrade of existing modelling frameworks in order to evaluate their efficiency in mitigating the impact of urban drainage systems on receiving water bodies. While storage tank modelling approaches are quite well documented in literature, some gaps are still present about infiltration facilities mainly dependent on the complexity of the involved physical processes. In this study, a simplified conceptual modelling approach for the simulation of the infiltration trenches is presented. The model enables to assess the performance of infiltration trenches. The main goal is to develop a model that can be employed for the assessment of the mitigation efficiency of infiltration trenches in an integrated urban drainage context. Particular care was given to the simulation of infiltration structures considering the performance reduction due to clogging phenomena. The proposed model has been compared with other simplified modelling approaches and with a physically based model adopted as benchmark. The model performed better compared to other approaches considering both unclogged facilities and the effect of clogging. On the basis of a long-term simulation of six years of rain data, the performance and the effectiveness of an infiltration trench measure are assessed. The study confirmed the important role played by the clogging phenomenon on such infiltration structures. PMID:19587416

  9. A Conceptual Modeling Approach for OLAP Personalization

    NASA Astrophysics Data System (ADS)

    Garrigós, Irene; Pardillo, Jesús; Mazón, Jose-Norberto; Trujillo, Juan

    Data warehouses rely on multidimensional models in order to provide decision makers with appropriate structures to intuitively analyze data with OLAP technologies. However, data warehouses may be potentially large and multidimensional structures become increasingly complex to be understood at a glance. Even if a departmental data warehouse (also known as data mart) is used, these structures would be also too complex. As a consequence, acquiring the required information is more costly than expected and decision makers using OLAP tools may get frustrated. In this context, current approaches for data warehouse design are focused on deriving a unique OLAP schema for all analysts from their previously stated information requirements, which is not enough to lighten the complexity of the decision making process. To overcome this drawback, we argue for personalizing multidimensional models for OLAP technologies according to the continuously changing user characteristics, context, requirements and behaviour. In this paper, we present a novel approach to personalizing OLAP systems at the conceptual level based on the underlying multidimensional model of the data warehouse, a user model and a set of personalization rules. The great advantage of our approach is that a personalized OLAP schema is provided for each decision maker contributing to better satisfy their specific analysis needs. Finally, we show the applicability of our approach through a sample scenario based on our CASE tool for data warehouse development.

  10. NADM Conceptual Model 1.0 -- A Conceptual Model for Geologic Map Information

    USGS Publications Warehouse

    North American Geologic Map Data Model (NADM) Steering Committee Data Model Design Team

    2004-01-01

    Executive Summary -- The NADM Data Model Design Team was established in 1999 by the North American Geologic Map Data Model Steering Committee (NADMSC) with the purpose of drafting a geologic map data model for consideration as a standard for developing interoperable geologic map-centered databases by state, provincial, and federal geological surveys. The model is designed to be a technology-neutral conceptual model that can form the basis for a web-based interchange format using evolving information technology (e.g., XML, RDF, OWL), and guide implementation of geoscience databases in a common conceptual framework. The intended purpose is to allow geologic information sharing between geologic map data providers and users, independent of local information system implementation. The model emphasizes geoscience concepts and relationships related to information presented on geologic maps. Design has been guided by an informal requirements analysis, documentation of existing databases, technology developments, and other standardization efforts in the geoscience and computer-science communities. A key aspect of the model is the notion that representation of the conceptual framework (ontology) that underlies geologic map data must be part of the model, because this framework changes with time and understanding, and varies between information providers. The top level of the model distinguishes geologic concepts, geologic representation concepts, and metadata. The geologic representation part of the model provides a framework for representing the ontology that underlies geologic map data through a controlled vocabulary, and for establishing the relationships between this vocabulary and a geologic map visualization or portrayal. Top-level geologic classes in the model are Earth material (substance), geologic unit (parts of the Earth), geologic age, geologic structure, fossil, geologic process, geologic relation, and geologic event.

  11. Alternate conceptual model of ground water flow at Yucca Mountain

    SciTech Connect

    1993-12-31

    Attempts to predict the performance of a high-level nuclear waste repository in the United States have lead to the development of alternative conceptual models of the ground watre flow field in which the repository will be located. This step has come about because of the lage uncertainties involved in predicting the movement of water and radionuclides through an unsaturated fractured rock. Further, one of the standards to which we are comparing performance is probabilistic, so we are forced to try to conceive of all credible scenarios by which ground water may intersect the repository horizon and perhaps transport radionuclides to a given compliance boundary. To simplify this task, the DOE set about identifying alternative conceptual models of ground water flow which are consistent with existing data. Modeling these concepts necessitates the use of simplifying assumptions. Among the modeling assumptions commonly utilized by analysts of the Yucca Mountain site are those of uniformly distributed, small volumes of recharge and matrix or porous media flow. Most scientists would agree that recharge at Yucca Mountain does not occur in this ideal and simplified fashion, yet modeling endeavors continue to commonly utilize this approach. In this paper, we examine the potential effects of focused recharge on the flow field at Yucca Mountain in concert with a fractured matrix and non-equilibrium view of ground water flow.

  12. Comparison of two conceptual models of flow using the TSA

    SciTech Connect

    Wilson, M.L.

    1992-01-01

    As part of the performance-assessment task for the potential repository site at Yucca Mountain, Nevada, Sandia National Laboratories is developing a set of programs called the Total-System Analyzer (TSA). The TSA is one of the tools being used in the current effort to provide a systematic preliminary estimate the total-system performance of the Yucca Mountain site. The purposes of this paper are twofold: (1) to describe capabilities that have been added to the TSA in the last year; and (2) to present a comparison of two conceptual models of unsaturated-zone flow and transport, in terms of the performance measure specified by the Environmental Protection Agency (EPA) in 40 CFR Part 191. The conceptual-model comparison is intended to demonstrate the new TSA capabilities and at the same time shed some light on the performance implications of fracture flow at Yucca Mountain. Unsaturated fracture flow is not yet well understood, and it is of great importance in determining the performance of Yucca Mountain.

  13. A conceptual, distributed snow redistribution model

    NASA Astrophysics Data System (ADS)

    Frey, S.; Holzmann, H.

    2015-11-01

    When applying conceptual hydrological models using a temperature index approach for snowmelt to high alpine areas often accumulation of snow during several years can be observed. Some of the reasons why these "snow towers" do not exist in nature are vertical and lateral transport processes. While snow transport models have been developed using grid cell sizes of tens to hundreds of square metres and have been applied in several catchments, no model exists using coarser cell sizes of 1 km2, which is a common resolution for meso- and large-scale hydrologic modelling (hundreds to thousands of square kilometres). In this paper we present an approach that uses only gravity and snow density as a proxy for the age of the snow cover and land-use information to redistribute snow in alpine basins. The results are based on the hydrological modelling of the Austrian Inn Basin in Tyrol, Austria, more specifically the Ötztaler Ache catchment, but the findings hold for other tributaries of the river Inn. This transport model is implemented in the distributed rainfall-runoff model COSERO (Continuous Semi-distributed Runoff). The results of both model concepts with and without consideration of lateral snow redistribution are compared against observed discharge and snow-covered areas derived from MODIS satellite images. By means of the snow redistribution concept, snow accumulation over several years can be prevented and the snow depletion curve compared with MODIS (Moderate Resolution Imaging Spectroradiometer) data could be improved, too. In a 7-year period the standard model would lead to snow accumulation of approximately 2900 mm SWE (snow water equivalent) in high elevated regions whereas the updated version of the model does not show accumulation and does also predict discharge with more accuracy leading to a Kling-Gupta efficiency of 0.93 instead of 0.9. A further improvement can be shown in the comparison of MODIS snow cover data and the calculated depletion curve, where

  14. Hydrogeologic framework, hydrology, and refined conceptual model of groundwater flow for Coastal Plain aquifers at the Standard Chlorine of Delaware, Inc. Superfund Site, New Castle County, Delaware, 2005-12

    USGS Publications Warehouse

    Brayton, Michael J.; Cruz, Roberto M.; Myers, Luke; Degnan, James R.; Raffensperger, Jeff P.

    2015-01-01

    The regional hydrogeologic framework indicates that the site is underlain by Coastal Plain sediments of the Columbia, Merchantville, and Potomac Formations. Two primary aquifers underlying the site, the Columbia and the upper Potomac, are separated by the Merchantville Formation confining unit. Local groundwater flow in the surficial (Columbia) aquifer is controlled by topography and generally flows northward and discharges to nearby surface water. Regional flow within the Potomac aquifer is towards the southeast, and is strongly influenced by major water withdrawals locally. Previous investigations at the site indicated that contaminants, primarily benzene and chlorinated benzene compounds, were present in the Columbia aquifer in most locations; however, there were only limited detections in the upper Potomac aquifer as of 2004. From 2005 through 2012, the USGS designed a monitoring network, assisted with exploratory drilling, collected data at monitoring wells, conducted geophysical surveys, evaluated water-level responses in wells during pumping of a production well, and evaluated major aquifer withdrawals. Data collected through these efforts were used to refine the local conceptual flow system. The refined conceptual flow system for the site includes: (a) identification of gaps in confining units in the study area, (b) identification and correlation of multiple water-bearing sand intervals within the upper Potomac Formation, (c) connections between groundwater and surface water, (d) connections between shallow and deeper groundwater, (e) new water-level (or potentiometric surface) maps and inferred flow directions, and (f) identification of major local pumping well influences. The implications of the revised conceptual flow system on the occurrence and movement of site contaminants are that the resulting detection of contaminants in the upper Potomac aquifer at specific well locations can be attributed primarily to either advective lateral transport, direct

  15. Conceptualizing Telehealth in Nursing Practice: Advancing a Conceptual Model to Fill a Virtual Gap.

    PubMed

    Nagel, Daniel A; Penner, Jamie L

    2016-03-01

    Increasingly nurses use various telehealth technologies to deliver health care services; however, there has been a lag in research and generation of empirical knowledge to support nursing practice in this expanding field. One challenge to generating knowledge is a gap in development of a comprehensive conceptual model or theoretical framework to illustrate relationships of concepts and phenomena inherent to adoption of a broad range of telehealth technologies to holistic nursing practice. A review of the literature revealed eight published conceptual models, theoretical frameworks, or similar entities applicable to nursing practice. Many of these models focus exclusively on use of telephones and four were generated from qualitative studies, but none comprehensively reflect complexities of bridging nursing process and elements of nursing practice into use of telehealth. The purpose of this article is to present a review of existing conceptual models and frameworks, discuss predominant themes and features of these models, and present a comprehensive conceptual model for telehealth nursing practice synthesized from this literature for consideration and further development. This conceptual model illustrates characteristics of, and relationships between, dimensions of telehealth practice to guide research and knowledge development in provision of holistic person-centered care delivery to individuals by nurses through telehealth technologies. PMID:25858897

  16. Conceptual model for heart failure disease management.

    PubMed

    Andrikopoulou, Efstathia; Abbate, Kariann; Whellan, David J

    2014-03-01

    The objective of this review is to propose a conceptual model for heart failure (HF) disease management (HFDM) and to define the components of an efficient HFDM plan in reference to this model. Articles that evaluated 1 or more of the following aspects of HFDM were reviewed: (1) outpatient clinic follow-up; (2) self-care interventions to enhance patient skills; and (3) remote evaluation of worsening HF either using structured telephone support (STS) or by monitoring device data (telemonitoring). The success of programs in reducing readmissions and mortality were mixed. Outpatient follow-up programs generally resulted in improved outcomes, including decreased readmissions. Based on 1 meta-analysis, specialty clinics improved outcomes and nonspecialty clinics did not. Results from self-care programs were inconsistent and might have been affected by patient cognitive status and educational level, and intervention intensity. Telemonitoring, despite initially promising meta-analyses demonstrating a decrease in the number and duration of HF-related readmissions and all-cause mortality rates at follow-up, has not been shown in randomized trials to consistently reduce readmissions or mortality. However, evidence from device monitoring trials in particular might have been influenced by technology and design issues that might be rectified in future trials. Results from the literature suggest that the ideal HFDM plan would include outpatient follow-up at an HF specialty clinic and continuous education to improve patient self-care. The end result of this plan would lead to better understanding on the part of the patient and improved patient ability to recognize and respond to signs of decompensation. PMID:24565255

  17. Conceptual and Numerical Models for UZ Flow and Transport

    SciTech Connect

    H. Liu

    2000-03-03

    The purpose of this Analysis/Model Report (AMR) is to document the conceptual and numerical models used for modeling of unsaturated zone (UZ) fluid (water and air) flow and solute transport processes. This is in accordance with ''AMR Development Plan for U0030 Conceptual and Numerical Models for Unsaturated Zone (UZ) Flow and Transport Processes, Rev 00''. The conceptual and numerical modeling approaches described in this AMR are used for models of UZ flow and transport in fractured, unsaturated rock under ambient and thermal conditions, which are documented in separate AMRs. This AMR supports the UZ Flow and Transport Process Model Report (PMR), the Near Field Environment PMR, and the following models: Calibrated Properties Model; UZ Flow Models and Submodels; Mountain-Scale Coupled Processes Model; Thermal-Hydrologic-Chemical (THC) Seepage Model; Drift Scale Test (DST) THC Model; Seepage Model for Performance Assessment (PA); and UZ Radionuclide Transport Models.

  18. A Logical Model of Conceptual Integrity in Data Integration

    PubMed Central

    Flater, David

    2003-01-01

    Conceptual integrity is required for the result of data integration to be cohesive and sensible. Compromised conceptual integrity results in “semantic faults,” which are commonly blamed for latent integration bugs. A logical model of conceptual integrity in data integration and a simple example application are presented. Unlike constructive models that attempt to prevent semantic faults, this model allows both correct and incorrect integrations to be described. Imperfect legacy systems can therefore be modeled, allowing a more formal analysis of their flaws and the possible remedies.

  19. Model of Conceptual Change for INQPRO: A Bayesian Network Approach

    ERIC Educational Resources Information Center

    Ting, Choo-Yee; Sam, Yok-Cheng; Wong, Chee-Onn

    2013-01-01

    Constructing a computational model of conceptual change for a computer-based scientific inquiry learning environment is difficult due to two challenges: (i) externalizing the variables of conceptual change and its related variables is difficult. In addition, defining the causal dependencies among the variables is also not trivial. Such difficulty…

  20. Using Conceptual Change Theories to Model Position Concepts in Astronomy

    ERIC Educational Resources Information Center

    Yang, Chih-Chiang; Hung, Jeng-Fung

    2012-01-01

    The roles of conceptual change and model building in science education are very important and have a profound and wide effect on teaching science. This study examines the change in children's position concepts after instruction, based on different conceptual change theories. Three classes were chosen and divided into three groups, including a…

  1. A conceptual graphs modeling of UMLS components.

    PubMed

    Joubert, M; Miton, F; Fieschi, M; Robert, J J

    1995-01-01

    The Unified Medical Language System (UMLS) of the U.S. National Library of Medicine is a complex collection of terms, concepts, and relationships derived from standard classifications. Potential applications would benefit from a high level representation of its components. This paper proposes a conceptual representation of both the Metathesaurus and the Semantic Network of the UMLS based on conceptual graphs. It shows that the addition of a dictionary of concepts to the UMLS knowledge base allows the capability to exploit it pertinently. This dictionary defines more precisely the core concepts and adds constraints on their use. Constraints are dedicated to guide an "intelligent" browsing of the UMLS knowledge sources. PMID:8591348

  2. Challenges in Requirements Engineering: A Research Agenda for Conceptual Modeling

    NASA Astrophysics Data System (ADS)

    March, Salvatore T.; Allen, Gove N.

    Domains for which information systems are developed deal primarily with social constructions—conceptual objects and attributes created by human intentions and for human purposes. Information systems play an active role in these domains. They document the creation of new conceptual objects, record and ascribe values to their attributes, initiate actions within the domain, track activities performed, and infer conclusions based on the application of rules that govern how the domain is affected when socially-defined and identified causal events occur. Emerging applications of information technologies evaluate such business rules, learn from experience, and adapt to changes in the domain. Conceptual modeling grammars aimed at representing their system requirements must include conceptual objects, socially-defined events, and the rules pertaining to them. We identify challenges to conceptual modeling research and pose an ontology of the artificial as a step toward meeting them.

  3. Building of a conceptual model at the UE25-c hole complex

    SciTech Connect

    Karasaki, K.; Landsfeld, M.; Grossenbacher, K.

    1990-10-01

    This paper discusses construction of a conceptual model of the UE25-c hole complex. An interdisciplinary approach is discussed where all the available data are integrated. Site geology, borehole geophysics and hydraulic test results at UE25-c hole complex suggest that groundwater flow may be controlled by fractures and faults. A model is proposed.

  4. Overtraining and recovery. A conceptual model.

    PubMed

    Kenttä, G; Hassmén, P

    1998-07-01

    importance of active measures to improve the recovery process. Furthermore, directing attention to psychophysiological cues serves the same purpose as in RPE, i.e. increasing self-awareness. This article reviews and conceptualises the whole overtraining process. In doing so, it (i) aims to differentiate between the types of stress affecting an athlete's performance: (ii) identifies factors influencing an athlete's ability to adapt to physical training: (iii) structures the recovery process. The TQR method to facilitate monitoring of the recovery process is then suggested and a conceptual model that incorporates all of the important parameters for performance gain (adaptation) and loss (maladaptation). PMID:9739537

  5. An Integrative-Interactive Conceptual Model for Curriculum Development.

    ERIC Educational Resources Information Center

    Al-Ibrahim, Abdul Rahman H.

    1982-01-01

    The Integrative-Interactive Conceptual Model for Curriculum Development calls for curriculum reform and innovation to be cybernetic so that all aspects of curriculum planning get adequate attention. (CJ)

  6. CONCEPTUAL MODEL DEVELOPMENT AND INFORMATION MANAGEMENT FRAMEWORK FOR DIAGNOSTICS RESEARCH

    EPA Science Inventory

    Conceptual model development will focus on the effects of habitat alteration, nutrients,suspended and bedded sediments, and toxic chemicals on appropriate endpoints (individuals, populations, communities, ecosystems) across spatial scales (habitats, water body, watershed, region)...

  7. Towards a Model of Technology Adoption: A Conceptual Model Proposition

    NASA Astrophysics Data System (ADS)

    Costello, Pat; Moreton, Rob

    A conceptual model for Information Communication Technology (ICT) adoption by Small Medium Enterprises (SMEs) is proposed. The research uses several ICT adoption models as its basis with theoretical underpinning provided by the Diffusion of Innovation theory and the Technology Acceptance Model (TAM). Taking an exploratory research approach the model was investigated amongst 200 SMEs whose core business is ICT. Evidence from this study demonstrates that these SMEs face the same issues as all other industry sectors. This work points out weaknesses in SMEs environments regarding ICT adoption and suggests what they may need to do to increase the success rate of any proposed adoption. The methodology for development of the framework is described and recommendations made for improved Government-led ICT adoption initiatives. Application of the general methodology has resulted in new opportunities to embed the ethos and culture surrounding the issues into the framework of new projects developed as a result of Government intervention. A conceptual model is proposed that may lead to a deeper understanding of the issues under consideration.

  8. Conceptual Models and the Future of Special Education

    ERIC Educational Resources Information Center

    Kauffman, James M.

    2007-01-01

    A medical model has advantages over a legal model in thinking about special education, especially in responding supportively to difference, meeting individual needs, and practicing prevention. The legal conceptual model now dominates thinking about special education, but a medical model promises a brighter future for special education and for…

  9. Postclosure performance assessment of the SCP (Site Characterization Plan) conceptual design for horizontal emplacement: Revision 1

    SciTech Connect

    Not Available

    1987-08-01

    This report is a preliminary postclosure performance assessment of the repository design specified in the Site Characterization Plan Conceptual Design Report (SCP-CDR) for horizontal emplacement of high-level nuclear waste. At the time that these analyses were done, horizontal emplacement was the preferred orientation for the waste packages but vertical emplacement is now the reference design. This assessment consists of (1) a review of the regulatory requirements and strategy to demonstrate compliance with these requirements, (2) an analysis of the performance of the total repository system, (3) an analysis of the thermomechanical behavior of the repository, (4) an analysis of brine mobility in the repository, (5) an analysis of the waste package performance, (6) an analysis of the performance of seals, and (7) comments on the sensitivity of the various performance measures to uncertainties in the data and models. These are preliminary analyses and, in most cases, involve bounding calculations of the repository behavior. They have several purposes including (1) assessing how well this conceptual design ''measures up'' against requirements, (2) gaining experience in implementing the performance assessment strategy and tools and thereby learning where improvements are needed, (3) helping to identify needed data, and (4) helping to indicate required design modifications. 26 refs., 40 figs., 20 tabs.

  10. Sensitivity of hydrological performance assessment analysis to variations in material properties, conceptual models, and ventilation models

    SciTech Connect

    Sobolik, S.R.; Ho, C.K.; Dunn, E.; Robey, T.H.; Cruz, W.T.

    1996-07-01

    The Yucca Mountain Site Characterization Project is studying Yucca Mountain in southwestern Nevada as a potential site for a high-level nuclear waste repository. Site characterization includes surface- based and underground testing. Analyses have been performed to support the design of an Exploratory Studies Facility (ESF) and the design of the tests performed as part of the characterization process, in order to ascertain that they have minimal impact on the natural ability of the site to isolate waste. The information in this report pertains to sensitivity studies evaluating previous hydrological performance assessment analyses to variation in the material properties, conceptual models, and ventilation models, and the implications of this sensitivity on previous recommendations supporting ESF design. This document contains information that has been used in preparing recommendations for Appendix I of the Exploratory Studies Facility Design Requirements document.

  11. Climate model uncertainty versus conceptual geological uncertainty in hydrological modeling

    NASA Astrophysics Data System (ADS)

    Sonnenborg, T. O.; Seifert, D.; Refsgaard, J. C.

    2015-09-01

    Projections of climate change impact are associated with a cascade of uncertainties including in CO2 emission scenarios, climate models, downscaling and impact models. The relative importance of the individual uncertainty sources is expected to depend on several factors including the quantity that is projected. In the present study the impacts of climate model uncertainty and geological model uncertainty on hydraulic head, stream flow, travel time and capture zones are evaluated. Six versions of a physically based and distributed hydrological model, each containing a unique interpretation of the geological structure of the model area, are forced by 11 climate model projections. Each projection of future climate is a result of a GCM-RCM model combination (from the ENSEMBLES project) forced by the same CO2 scenario (A1B). The changes from the reference period (1991-2010) to the future period (2081-2100) in projected hydrological variables are evaluated and the effects of geological model and climate model uncertainties are quantified. The results show that uncertainty propagation is context-dependent. While the geological conceptualization is the dominating uncertainty source for projection of travel time and capture zones, the uncertainty due to the climate models is more important for groundwater hydraulic heads and stream flow.

  12. Climate model uncertainty vs. conceptual geological uncertainty in hydrological modeling

    NASA Astrophysics Data System (ADS)

    Sonnenborg, T. O.; Seifert, D.; Refsgaard, J. C.

    2015-04-01

    Projections of climate change impact are associated with a cascade of uncertainties including CO2 emission scenario, climate model, downscaling and impact model. The relative importance of the individual uncertainty sources is expected to depend on several factors including the quantity that is projected. In the present study the impacts of climate model uncertainty and geological model uncertainty on hydraulic head, stream flow, travel time and capture zones are evaluated. Six versions of a physically based and distributed hydrological model, each containing a unique interpretation of the geological structure of the model area, are forced by 11 climate model projections. Each projection of future climate is a result of a GCM-RCM model combination (from the ENSEMBLES project) forced by the same CO2 scenario (A1B). The changes from the reference period (1991-2010) to the future period (2081-2100) in projected hydrological variables are evaluated and the effects of geological model and climate model uncertainties are quantified. The results show that uncertainty propagation is context dependent. While the geological conceptualization is the dominating uncertainty source for projection of travel time and capture zones, the uncertainty on the climate models is more important for groundwater hydraulic heads and stream flow.

  13. CONCEPTUAL FRAMEWORK FOR REGRESSION MODELING OF GROUND-WATER FLOW.

    USGS Publications Warehouse

    Cooley, Richard L.

    1985-01-01

    The author examines the uses of ground-water flow models and which classes of use require treatment of stochastic components. He then compares traditional and stochastic procedures for modeling actual (as distinguished from hypothetical) systems. Finally, he examines the conceptual basis and characteristics of the regression approach to modeling ground-water flow.

  14. Developing Models of Communicative Competence: Conceptual, Statistical, and Methodological Considerations.

    ERIC Educational Resources Information Center

    Cziko, Gary A.

    The development of an empirically based model of communicative competence is discussed in terms of conceptual, statistical, and methodological considerations. A distinction is made between descriptive and working models of communicative competence. Working models attempt to show how components of communicative competence are interrelated…

  15. A Conceptual Model of Career Development to Enhance Academic Motivation

    ERIC Educational Resources Information Center

    Collins, Nancy Creighton

    2010-01-01

    The purpose of this study was to develop, refine, and validate a conceptual model of career development to enhance the academic motivation of community college students. To achieve this end, a straw model was built from the theoretical and empirical research literature. The model was then refined and validated through three rounds of a Delphi…

  16. A Conceptual Model To Assist Educational Leaders Manage Change.

    ERIC Educational Resources Information Center

    Cochren, John R.

    This paper presents a conceptual model to help school leaders manage change effectively. The model was developed from a literature review of theory development and model construction. Specifically, the paper identifies the major components that inhibit organizational change, and synthesizes the most salient features of these components through a…

  17. Implementations Are Not Conceptualizations: Revising the Verb Learning Model.

    ERIC Educational Resources Information Center

    MacWhinney, Brian; Leinbach, Jared

    A model of the child's learning of the past tense forms of English verbs is discussed. This connectionist model takes as input a present-tense verb and provides as output a past tense form. A new simulation is applied to 13 problems raised by critics of the model, presented as fundamental flaws in the conceptualizations underlying connectionism.…

  18. A conceptual model for determining career choice of CHROME alumna based on farmer's conceptual models

    NASA Astrophysics Data System (ADS)

    Moore, Lisa Simmons

    This qualitative program evaluation examines the career decision-making processes and career choices of nine, African American women who participated in the Cooperating Hampton Roads Organization for Minorities in Engineering (CHROME) and who graduated from urban, rural or suburban high schools in the year 2000. The CHROME program is a nonprofit, pre-college intervention program that encourages underrepresented minority and female students to enter science, technically related, engineering, and math (STEM) career fields. The study describes career choices and decisions made by each participant over a five-year period since high school graduation. Data was collected through an Annual Report, Post High School Questionnaires, Environmental Support Questionnaires, Career Choice Questionnaires, Senior Reports, and standardized open-ended interviews. Data was analyzed using a model based on Helen C. Farmer's Conceptual Models, John Ogbu's Caste Theory and Feminist Theory. The CHROME program, based on its stated goals and tenets, was also analyzed against study findings. Findings indicated that participants received very low levels of support from counselors and teachers to pursue STEM careers and high levels of support from parents and family, the CHROME program and financial backing. Findings of this study also indicated that the majority of CHROME alumna persisted in STEM careers. The most successful participants, in terms of undergraduate degree completion and occupational prestige, were the African American women who remained single, experienced no critical incidents, came from a middle class to upper middle class socioeconomic background, and did not have children.

  19. Identifying students' mental models of sound propagation: The role of conceptual blending in understanding conceptual change

    NASA Astrophysics Data System (ADS)

    Hrepic, Zdeslav; Zollman, Dean A.; Rebello, N. Sanjay

    2010-07-01

    We investigated introductory physics students’ mental models of sound propagation. We used a phenomenographic method to analyze the data in the study. In addition to the scientifically accepted Wave model, students used the “Entity” model to describe the propagation of sound. In this latter model sound is a self-standing entity, different from the medium through which it propagates. All other observed alternative models contain elements of both Entity and Wave models, but at the same time are distinct from each of the constituent models. We called these models “hybrid” or “blend” models. We discuss how students use these models in various contexts before and after instruction and how our findings contribute to the understanding of conceptual change. Implications of our findings for teaching are summarized.

  20. Conceptual model for transferring information between small watersheds

    USGS Publications Warehouse

    Cleaves, E.T.

    2003-01-01

    Stream and watershed management and restoration can be greatly facilitated through use of physiographic landform classification to organize and communicate natural resource, hazard, and environmental information at a broad scale (1:250,000) as illustrated by the Piedmont and Coastal Plain Provinces in Maryland, or at a small scale (1:24,000) as illustrated using divisions and zones combined with a conceptual model. The conceptual model brings together geology, surficial processes, landforms and land use change information at the small watershed scale and facilitates transfer of information from one small watershed to another with similar geology and landforms. Stream flow, sediment erosion, and water quality illustrate the use of the model.

  1. Supporting user-defined granularities in a spatiotemporal conceptual model

    USGS Publications Warehouse

    Khatri, V.; Ram, S.; Snodgrass, R.T.; O'Brien, G. M.

    2002-01-01

    Granularities are integral to spatial and temporal data. A large number of applications require storage of facts along with their temporal and spatial context, which needs to be expressed in terms of appropriate granularities. For many real-world applications, a single granularity in the database is insufficient. In order to support any type of spatial or temporal reasoning, the semantics related to granularities needs to be embedded in the database. Specifying granularities related to facts is an important part of conceptual database design because under-specifying the granularity can restrict an application, affect the relative ordering of events and impact the topological relationships. Closely related to granularities is indeterminacy, i.e., an occurrence time or location associated with a fact that is not known exactly. In this paper, we present an ontology for spatial granularities that is a natural analog of temporal granularities. We propose an upward-compatible, annotation-based spatiotemporal conceptual model that can comprehensively capture the semantics related to spatial and temporal granularities, and indeterminacy without requiring new spatiotemporal constructs. We specify the formal semantics of this spatiotemporal conceptual model via translation to a conventional conceptual model. To underscore the practical focus of our approach, we describe an on-going case study. We apply our approach to a hydrogeologic application at the United States Geologic Survey and demonstrate that our proposed granularity-based spatiotemporal conceptual model is straightforward to use and is comprehensive.

  2. Conceptual design report, TWRS Privatization Phase I, site development and roads, subproject W-505

    SciTech Connect

    Singh, G.

    1997-06-05

    This document includes Conceptual Design Report (CDR) for the site development, construction of new roads and improvements at existing road intersections, habitat mitigation, roadway lighting, and construction power needed for the construction of two Private Contractor (PC) Facilities. Approximately 50 hectare (124 acres) land parcel, east of the Grout Facility, is planned for the PC facilities.

  3. A Conceptual Model of Multiple Dimensions of Identity.

    ERIC Educational Resources Information Center

    Jones, Susan R.; McEwen, Marylu K.

    2000-01-01

    Presents a conceptual model of multiple dimensions of identity, which depicts a core sense of self or one's personal identity. Intersecting circles surrounding the core identity represent significant identity dimensions and contextual influences. The model evolved from a grounded theory study of a group of 10 women college students ranging in age…

  4. Conceptual model for assessment of inhalation exposure: defining modifying factors.

    PubMed

    Tielemans, Erik; Schneider, Thomas; Goede, Henk; Tischer, Martin; Warren, Nick; Kromhout, Hans; Van Tongeren, Martie; Van Hemmen, Joop; Cherrie, John W

    2008-10-01

    The present paper proposes a source-receptor model to schematically describe inhalation exposure to help understand the complex processes leading to inhalation of hazardous substances. The model considers a stepwise transfer of a contaminant from the source to the receptor. The conceptual model is constructed using three components, i.e. (i) the source, (ii) various transmission compartments and (iii) the receptor, and describes the contaminant's emission and its pattern of transport. Based on this conceptual model, a list of nine mutually independent principal modifying factors (MFs) is proposed: activity emission potential, substance emission potential, localized control, separation, segregation, dilution, worker behavior, surface contamination and respiratory protection. These MFs describe the exposure process at a high level of abstraction so that the model can be generically applicable. A list of exposure determinants underlying each of these principal MFs is proposed to describe the exposure process at a more detailed level. The presented conceptual model is developed in conjunction with an activity taxonomy as described in a separate paper. The proposed conceptual model and MFs should be seen as 'building blocks' for development of higher tier exposure models. PMID:18787181

  5. Revisiting "Discrepancy Analysis in Continuing Medical Education: A Conceptual Model"

    ERIC Educational Resources Information Center

    Fox, Robert D.

    2011-01-01

    Based upon a review and analysis of selected literature, the author presents a conceptual model of discrepancy analysis evaluation for planning, implementing, and assessing the impact of continuing medical education (CME). The model is described in terms of its value as a means of diagnosing errors in the development and implementation of CME. The…

  6. What Is FRBR? A Conceptual Model for the Bibliographic Universe

    ERIC Educational Resources Information Center

    Tillett, Barbara

    2005-01-01

    From 1992 to 1995 the IFLA Study Group on Functional Requirements for Bibliographic Records (FRBR) developed an entity relationship model as a generalised view of the bibliographic universe, intended to be independent of any cataloguing code or implementation. The FRBR report itself includes a description of the conceptual model (the entities,…

  7. A Conceptual Model For Effluent-Dependent Riverine Environments

    NASA Astrophysics Data System (ADS)

    Murphy, M. T.; Meyerhoff, R. D.; Osterkamp, W. R.; Smith, E. L.; Hawkins, R. H.

    2001-12-01

    The Arid West Water Quality Research Project (WQRP) is a multi-year, EPA-funded scientific endeavor directed by the Pima County, Wastewater Management Department in southern Arizona and focussed upon several interconnected ecological questions. These questions are crucial to water quality management in the arid and semi arid western US. A key component has been the ecological, hydrological and geomorphological investigation of habitat created by the discharge of treated effluent into ephemeral streams. Such environments are fundamentally different from the dry streams or rivers they displace; however, they are clearly not the perennial streams they superficially resemble. Under Arizona State regulations, such streams can bear the use designation of "Effluent Dependent Waters," or EDWs. Before this investigation, a hydrological/ecological conceptual model for these unique ecosystems had not been published. We have constructed one for general review that is designed to direct future work in the WQRP. The project investigated ten representative, yet contrasting EDW sites distributed throughout arid areas of the western US, to gather both historical and reconnaissance level field data, including in-stream and riparian, habitat and morphometric fluvial data. In most cases, the cross sectional area of the prior channel is oversized relative to the discharge of the introduced effluent. Where bed control is absent, the channels are incised downstream of the discharge point, further suggesting a disequilibrium between the channel and the regulated effluent flow. Several of the studied stream systems primarily convey storm water and are aggradational, exhibiting braided or anastomizing channels, high energy bedforms, and spatially dynamic interfluves. Active channels are formed in response to individual storm events and can be highly dynamic in both location and cross-sectional morphology. This poses a geomorphological challenge in the selection of a discharge point. We

  8. A Conceptual Critique of Sternberg's WICS Model

    ERIC Educational Resources Information Center

    Koro-Ljungberg, Mirka

    2003-01-01

    Robert Sternberg's model of giftedness brings together interesting and very important elements of giftedness by synthesizing wisdom, intelligence, and creativity in novel ways. While his model is based on extensive research and utilizes a variety of sources and expertise, the epistemological consistency of Sternberg's model is, in the author's…

  9. From models to performance assessment: the conceptualization problem.

    PubMed

    Bredehoeft, John D

    2003-01-01

    Today, models are ubiquitous tools for ground water analyses. The intent of this paper is to explore philosophically the role of the conceptual model in analysis. Selection of the appropriate conceptual model is an a priori decision by the analyst. Calibration is an integral part of the modeling process. Unfortunately a wrong or incomplete conceptual model can often be adequately calibrated; good calibration of a model does not ensure a correct conceptual model. Petroleum engineers have another term for calibration; they refer to it as history matching. A caveat to the idea of history matching is that we can make a prediction with some confidence equal to the period of the history match. In other words, if we have matched a 10-year history, we can predict for 10 years with reasonable confidence; beyond 10 years the confidence in the prediction diminishes rapidly. The same rule of thumb applies to ground water model analyses. Nuclear waste disposal poses a difficult problem because the time horizon, 1000 years or longer, is well beyond the possibility of the history match (or period of calibration) in the traditional analysis. Nonetheless, numerical models appear to be the tool of choice for analyzing the safety of waste facilities. Models have a well-recognized inherent uncertainty. Performance assessment, the technique for assessing the safety of nuclear waste facilities, involves an ensemble of cascading models. Performance assessment with its ensemble of models multiplies the inherent uncertainty of the single model. The closer we can approach the idea of a long history with which to match the models, even models of nuclear waste facilities, the more confidence we will have in the analysis (and the models, including performance assessment). This thesis argues for prolonged periods of observation (perhaps as long as 300 to 1000 years) before a nuclear waste facility is finally closed. PMID:13678111

  10. Conceptual hydrogeological model of a coastal hydrosystem in the mediterranean

    NASA Astrophysics Data System (ADS)

    Mitropapas, Anastasios; Pouliaris, Christos; Apostolopoulos, Georgios; Vasileiou, Eleni; Schüth, Christoph; Vienken, Thomas; Dietrich, Peter; Kallioras, Andreas

    2016-04-01

    Groundwater resources management in the Mediterranean basin is an issue of paramount importance that becomes a necessity in the case of the coastal hydrosystems. Coastal aquifers are considered very sensitive ecosystems that are subject to several stresses being of natural or anthropogenic origin. The coastal hydrosystem of Lavrion can be used as a reference site that incorporates multi-disciplinary environmental problems, which are typical for Circum-Mediterranean. This study presents the synthesis of a wide range of field activities within the area of Lavrion including the monitoring of water resources within all hydrologic zones (surface, unsaturated and saturated) and geophysical (invasive and non-invasive) surveys. Different monitoring approaches -targeting to the collection of hydrochemical, geophysical, geological, hydrological data- were applied, that proved to provide a sound characterization of the groundwater flows within the coastal karstic system in connection to the surrounding water bodies of the study area. The above are used as input parameters process during the development of the conceptual model of the coastal hydrosystem of Lavrion. Key-words: Coastal hydrosystems, Mediterranean basin, seawater intrusion

  11. Designing Public Library Websites for Teens: A Conceptual Model

    ERIC Educational Resources Information Center

    Naughton, Robin Amanda

    2012-01-01

    The main goal of this research study was to develop a conceptual model for the design of public library websites for teens (TLWs) that would enable designers and librarians to create library websites that better suit teens' information needs and practices. It bridges a gap in the research literature between user interface design in…

  12. A Multiperspectival Conceptual Model of Transformative Meaning Making

    ERIC Educational Resources Information Center

    Freed, Maxine

    2009-01-01

    Meaning making is central to transformative learning, but little work has explored how meaning is constructed in the process. Moreover, no meaning-making theory adequately captures its characteristics and operations during radical transformation. The purpose of this dissertation was to formulate and specify a multiperspectival conceptual model of…

  13. A Conceptual Model of the World of Work.

    ERIC Educational Resources Information Center

    VanRooy, William H.

    The conceptual model described in this paper resulted from the need to organize a body of knowledge related to the world of work which would enable curriculum developers to prepare accurate, realistic instructional materials. The world of work is described by applying Malinowski's scientific study of the structural components of culture. It is…

  14. Conceptualizations of Creativity: Comparing Theories and Models of Giftedness

    ERIC Educational Resources Information Center

    Miller, Angie L.

    2012-01-01

    This article reviews seven different theories of giftedness that include creativity as a component, comparing and contrasting how each one conceptualizes creativity as a part of giftedness. The functions of creativity vary across the models, suggesting that while the field of gifted education often cites the importance of creativity, the…

  15. Sources of Sex Discrimination in Educational Systems: A Conceptual Model

    ERIC Educational Resources Information Center

    Kutner, Nancy G.; Brogan, Donna

    1976-01-01

    A conceptual model is presented relating numerous variables contributing to sexism in American education. Discrimination is viewed as intervening between two sets of interrelated independent variables and the dependent variable of sex inequalities in educational attainment. Sex-role orientation changes are the key to significant change in the…

  16. A Conceptual Model for Effective Distance Learning in Higher Education

    ERIC Educational Resources Information Center

    Farajollahi, Mehran; Zare, Hosein; Hormozi, Mahmood; Sarmadi, Mohammad Reza; Zarifsanaee, Nahid

    2010-01-01

    The present research aims at presenting a conceptual model for effective distance learning in higher education. Findings of this research shows that an understanding of the technological capabilities and learning theories especially constructive theory and independent learning theory and communicative and interaction theory in Distance learning is…

  17. Analysis of natural ground-water level variations for hydrogeologic conceptualization, Hanford Site, Washington

    NASA Astrophysics Data System (ADS)

    Nevulis, Richard H.; Davis, Donald R.; Sorooshian, Soroosh

    1989-07-01

    This study involves the analysis of groundwater level time series for the purpose of obtaining details for a conceptual hydrogeologic model at a time when conventional hydraulic stress testing was not feasible due to regulatory considerations. The study area is located in south central Washington in the Pasco Basin which was a candidate site for underground disposal of high-level radioactive nuclear wastes. Advantages of such passive methods of analysis may include relative simplicity, low cost, and avoidance of disturbances typically associated with stress testing of aquifers. Through this approach, natural and incidental man-made groundwater level variations, most of which are quite small, are examined by statistical and analytical methods in conjunction with hydrogeologic models to draw inferences on the hydrogeology. Vertical connectivity of the hydrostratigraphic units is also examined by analyzing groundwater level time series of five units at three piezometer nests. It is concluded that a combination of statistical/analytical approaches used in a complementary fashion can provide useful information about the hydrogeology of a given area. A meaningful analysis requires that there is (1) a source of influence on the groundwater levels, (2) a response to that influence, (3) a sufficiently long data record, and (4) measurement and analytical techniques which allow the detection and identification of the influence and response.

  18. A new conceptual model of convection

    SciTech Connect

    Walcek, C.

    1995-09-01

    Classical cumulus parameterizations assume that cumulus clouds are entraining plumes of hot air rising through the atmosphere. However, ample evidence shows that clouds cannot be simulated using this approach. Dr. Walcek suggests that cumulus clouds can be reasonably simulated by assuming that buoyant plumes detrain mass as they rise through the atmosphere. Walcek successfully simulates measurements of tropical convection using this detraining model of cumulus convection. Comparisons with measurements suggest that buoyant plumes encounter resistance to upward movement as they pass through dry layers in the atmosphere. This probably results from turbulent mixing and evaporation of cloud water, which generates negatively buoyant mixtures which detrain from the upward moving plume. This mass flux model of detraining plumes is considerably simpler than existing mass flux models, yet reproduces many of the measured effects associated with convective activity. 1 fig.

  19. Conceptualizing Evolving Models of Educational Development

    ERIC Educational Resources Information Center

    Fraser, Kym; Gosling, David; Sorcinelli, Mary Deane

    2010-01-01

    Educational development, which the authors use to refer to the field of professional and strategic development associated with university and college learning and teaching, can be described in many ways by referring to its different aspects. In this article the authors endeavor to categorize many of the models that have been used to describe…

  20. CONCEPTUAL DEVELOPMENT OF A TOXIC SCREENING MODEL

    EPA Science Inventory

    This report presents the application of the Routing and Graphical Display system developed by EPA to show how computer based modeling and simulation using the Reach File can be used to assess the types and concentrations of contaminants that could be found at any point in a river...

  1. A conceptual model of morphogenesis and regeneration

    PubMed Central

    Tosenberger, A.; Bessonov, N.; Levin, M.; Reinberg, N.; Volpert, V.; Morozova, N.

    2016-01-01

    This paper is devoted to computer modelling of the development and regeneration of multicellular biological structures. Some species (e.g., planaria and salamanders) are able to regenerate parts of their body after amputation damage, but the global rules governing cooperative cell behaviour during morphogenesis are not known. Here, we consider a simplified model organism, which consists of tissues formed around special cells that can be interpreted as stem cells. We assume that stem cells communicate with each other by a set of signals, and that the values of these signals depend on the distance between cells. Thus the signal distribution characterizes location of stem cells. If the signal distribution is changed, then the difference between the initial and the current signal distribution affects the behaviour of stem cells – e.g. as a result of an amputation of a part of tissue the signal distribution changes which stimulates stem cells to migrate to new locations, appropriate for regeneration of the proper pattern. Moreover, as stem cells divide and form tissues around them, they control the form and the size of regenerating tissues. This two-level organization of the model organism, with global regulation of stem cells and local regulation of tissues, allows its reproducible development and regeneration. PMID:25822060

  2. Conceptual ecological models to guide integrated landscape monitoring of the Great Basin

    USGS Publications Warehouse

    Miller, D.M.; Finn, S.P.; Woodward, Andrea; Torregrosa, Alicia; Miller, M.E.; Bedford, D.R.; Brasher, A.M.

    2010-01-01

    The Great Basin Integrated Landscape Monitoring Pilot Project was developed in response to the need for a monitoring and predictive capability that addresses changes in broad landscapes and waterscapes. Human communities and needs are nested within landscapes formed by interactions among the hydrosphere, geosphere, and biosphere. Understanding the complex processes that shape landscapes and deriving ways to manage them sustainably while meeting human needs require sophisticated modeling and monitoring. This document summarizes current understanding of ecosystem structure and function for many of the ecosystems within the Great Basin using conceptual models. The conceptual ecosystem models identify key ecological components and processes, identify external drivers, develop a hierarchical set of models that address both site and landscape attributes, inform regional monitoring strategy, and identify critical gaps in our knowledge of ecosystem function. The report also illustrates an approach for temporal and spatial scaling from site-specific models to landscape models and for understanding cumulative effects. Eventually, conceptual models can provide a structure for designing monitoring programs, interpreting monitoring and other data, and assessing the accuracy of our understanding of ecosystem functions and processes.

  3. A Conceptual Model of the Information Requirements of Nursing Organizations

    PubMed Central

    Miller, Emmy

    1989-01-01

    Three related issues play a role in the identification of the information requirements of nursing organizations. These issues are the current state of computer systems in health care organizations, the lack of a well-defined data set for nursing, and the absence of models representing data and information relevant to clinical and administrative nursing practice. This paper will examine current methods of data collection, processing, and storage in clinical and administrative nursing practice for the purpose of identifying the information requirements of nursing organizations. To satisfy these information requirements, database technology can be used; however, a model for database design is needed that reflects the conceptual framework of nursing and the professional concerns of nurses. A conceptual model of the types of data necessary to produce the desired information will be presented and the relationships among data will be delineated.

  4. Conceptual Commitments of the LIDA Model of Cognition

    NASA Astrophysics Data System (ADS)

    Franklin, Stan; Strain, Steve; McCall, Ryan; Baars, Bernard

    2013-06-01

    Significant debate on fundamental issues remains in the subfields of cognitive science, including perception, memory, attention, action selection, learning, and others. Psychology, neuroscience, and artificial intelligence each contribute alternative and sometimes conflicting perspectives on the supervening problem of artificial general intelligence (AGI). Current efforts toward a broad-based, systems-level model of minds cannot await theoretical convergence in each of the relevant subfields. Such work therefore requires the formulation of tentative hypotheses, based on current knowledge, that serve to connect cognitive functions into a theoretical framework for the study of the mind. We term such hypotheses "conceptual commitments" and describe the hypotheses underlying one such model, the Learning Intelligent Distribution Agent (LIDA) Model. Our intention is to initiate a discussion among AGI researchers about which conceptual commitments are essential, or particularly useful, toward creating AGI agents.

  5. Mercury Issues and Complexities in Oak Ridge, Tennessee; Redefining the Conceptual Model - 12277

    SciTech Connect

    Peterson, Mark; Southworth, George; Watson, David; Looney, Brian; Eddy-Dilek, Carol; Ketelle, Richard

    2012-07-01

    Releases of mercury from an industrial facility in Oak Ridge, Tennessee in the 1950's and early 1960's resulted in contamination of soil and groundwater within the facility, as well as downstream surface waters. Remediation efforts, which began in the 1980's, have decreased waterborne mercury concentrations near the facility, but elevated levels of mercury remain in the soil, sediment, water, and biota. Widespread distribution of mercury sources and complex mercury transport pathways are some of many challenges at the site. For effective environmental management and closure decision making relative to mercury contamination at the facilities, an up-to-date conceptual model of mercury source areas, processes, likely flow paths, and flux was deemed necessary. Recent facility and reconfiguration efforts, site characterizations, remedial actions, and research are facilitating the collection of new mercury data in Oak Ridge. To develop the current model, a multi-organizational team reviewed existing conceptual models from a variety of sources, consolidated historical data and source information, gathered input from local experts with extensive site knowledge, and used recently collected mercury data from a variety of sampling programs. The developed site conceptual model indicates that the nature and extent of mercury concentration and contaminant flux has significantly changed in the ten years since flux-based conceptual models were used for previous remedial action decisions. A new water treatment system has effectively reduced mercury inputs to the creek and is removing substantially greater quantities of mercury from groundwater than was expected. However, fish concentrations in downstream waters have not responded to decreased water concentrations in the stream. Flux from one large out-fall at the creek's headwaters appears to be a greater percentage of the overall flux leaving the site than previous years, albeit year to year variation in flux is large, and the

  6. Conceptual Model for Selenium Cycling in the Great Salt Lake

    NASA Astrophysics Data System (ADS)

    Johnson, W. P.; Conover, M. R.; Wurtsbaugh, W. A.; Adams, J.

    2006-12-01

    The conceptual model for Selenium cycling in the Great Salt Lake was developed to guide investigations in support of determining an open water selenium standard for the Great Salt Lake. The motivation to determine this particular selenium standard derives from public concern for a plan to allow disposal of reverse osmosis (RO) concentrate in the GSL, which would contain elevated concentrations of major and trace elements, including selenium. The development of an open water standard for selenium requires a working knowledge of the biological significance of existing selenium concentrations in the Great Salt Lake, as well as a working understanding of the likely changes of these concentrations over time given existing and proposed loads to the system. This working knowledge" is being represented in a conceptual model that accounts for selenium in various stocks" in the system (e.g. water, sediment, biota) and the flow" of selenium between stocks (e.g., precipitation and settling, volatilization, bioconcentration). It illustrates the critical pathway of selenium in the Great Salt Lake from water, to microorganisms, to brine shrimp and brine flies, to birds, and to their eggs. It also addresses the complexity of the GSL system: a) Spatially diverse, being comprised by four distinct bays and two layers, with major differences in salinity among their waters. b) Temporally dynamic, due to seasonal and inter-annual variations in runoff. The conceptual model is presently descriptive, but will serve as the basis for a semi-quantitative model that will be fed by data accumulated during subsequent investigations.

  7. Dixie Valley Engineered Geothermal System Exploration Methodology Project, Baseline Conceptual Model Report

    DOE Data Explorer

    Iovenitti, Joe

    2013-05-15

    The Engineered Geothermal System (EGS) Exploration Methodology Project is developing an exploration approach for EGS through the integration of geoscientific data. The Project chose the Dixie Valley Geothermal System in Nevada as a field laboratory site for methodlogy calibration purposes because, in the public domain, it is a highly characterized geothermal systems in the Basin and Range with a considerable amount of geoscience and most importantly, well data. This Baseline Conceptual Model report summarizes the results of the first three project tasks (1) collect and assess the existing public domain geoscience data, (2) design and populate a GIS database, and (3) develop a baseline (existing data) geothermal conceptual model, evaluate geostatistical relationships, and generate baseline, coupled EGS favorability/trust maps from +1km above sea level (asl) to -4km asl for the Calibration Area (Dixie Valley Geothermal Wellfield) to identify EGS drilling targets at a scale of 5km x 5km. It presents (1) an assessment of the readily available public domain data and some proprietary data provided by Terra-Gen Power, LLC, (2) a re-interpretation of these data as required, (3) an exploratory geostatistical data analysis, (4) the baseline geothermal conceptual model, and (5) the EGS favorability/trust mapping. The conceptual model presented applies to both the hydrothermal system and EGS in the Dixie Valley region.

  8. eLac - Conceptual Model for Flood Management

    NASA Astrophysics Data System (ADS)

    Rata, Marius; Florentin Draghia, Aurelian; Drobot, Radu; Matreata, Marius; Corbus, Ciprian

    2015-04-01

    This article reviews the conceptual model of the decision support system (DSS) for flood management activities introduced in the scope of e-LAC project. Following the general system architecture which has an emphasize on the water management decision processes, hydrologic and hydraulic models are introduced and discussed according to their specific DSS integration potential. Three directions are discussed in dedicated sections corresponding to the main modules defined in the conceptual model : the Water Basin Management Module (mainly implements the management decision flow, but manages also data exchange between hydrologic modeling module and hydraulic modeling module, allow real time visualization for hydrological data), the Hydrologic Modeling Module (manages all the modeling functionalities of rainfalls - runoff processes, providing continuous hydrologic forecasts with a variable time-step depending on the actual basin situation) and the Hydraulic Modeling Module (computes the flood's waves routing having as boundary upstream conditions the discharge hydrographs, generated both by catchment's upper area, river tributaries and inter-basins, respectively the rating curves, water level hydrograph or water surface slope as downstream condition). The GIS concepts are contextually reviewed based on their use as geospatial database for water management modeling, integration within hydrologic time courses, hydraulic modeling (from both software and management perspective), expert knowledge or mathematical modeling results (knowledge database, rules).

  9. Scientific and conceptual flaws of coercive treatment models in addiction.

    PubMed

    Uusitalo, Susanne; van der Eijk, Yvette

    2016-01-01

    In conceptual debates on addiction, neurobiological research has been used to support the idea that addicted drug users lack control over their addiction-related actions. In some interpretations, this has led to coercive treatment models, in which, the purpose is to 'restore' control. However, neurobiological studies that go beyond what is typically presented in conceptual debates paint a different story. In particular, they indicate that though addiction has neurobiological manifestations that make the addictive behaviour difficult to control, it is possible for individuals to reverse these manifestations through their own efforts. Thus, addicted individuals should not be considered incapable of making choices voluntarily, simply on the basis that addiction has neurobiological manifestations, and coercive treatment models of addiction should be reconsidered in this respect. PMID:26463621

  10. CONCEPTUAL MODELS AND METHODS TO GUIDE DIAGNOSTIC RESEARCH INTO CAUSES OF IMPAIRMENT TO AQUATIC ECOSYSTEMS

    EPA Science Inventory

    Methods and conceptual models to guide the development of tools for diagnosing the causes of biological impairment within aquatic ecosystems of the United States are described in this report. The conceptual models developed here address nutrients, suspended and bedded sediments (...

  11. Federal Facility Compliance Act: Conceptual Site Treatment Plan for Lawrence Livermore National Laboratory, Livermore, California

    SciTech Connect

    Not Available

    1993-10-01

    The Department of Energy (DOE) is required by section 3021(b) of the Resource Conservation and Recovery Act (RCRA), as amended by the Federal Facility Compliance Act (the Act), to prepare plans describing the development of treatment capacities and technologies for treating mixed waste. The Act requires site treatment plans (STPs or plans) to be developed for each site at which DOE generates or stores mixed waste and submitted to the State or EPA for approval, approval with modification, or disapproval. The Lawrence Livermore National Laboratory (LLNL) Conceptual Site Treatment Plan (CSTP) is the preliminary version of the plan required by the Act and is being provided to California, the US Environmental Protection Agency (EPA), and others for review. A list of the other DOE sites preparing CSTPs is included in Appendix 1.1 of this document. Please note that Appendix 1.1 appears as Appendix A, pages A-1 and A-2 in this document.

  12. Conceptual Models in Health Informatics Research: A Literature Review and Suggestions for Development

    PubMed Central

    2016-01-01

    Background Contributing to health informatics research means using conceptual models that are integrative and explain the research in terms of the two broad domains of health science and information science. However, it can be hard for novice health informatics researchers to find exemplars and guidelines in working with integrative conceptual models. Objectives The aim of this paper is to support the use of integrative conceptual models in research on information and communication technologies in the health sector, and to encourage discussion of these conceptual models in scholarly forums. Methods A two-part method was used to summarize and structure ideas about how to work effectively with conceptual models in health informatics research that included (1) a selective review and summary of the literature of conceptual models; and (2) the construction of a step-by-step approach to developing a conceptual model. Results The seven-step methodology for developing conceptual models in health informatics research explained in this paper involves (1) acknowledging the limitations of health science and information science conceptual models; (2) giving a rationale for one’s choice of integrative conceptual model; (3) explicating a conceptual model verbally and graphically; (4) seeking feedback about the conceptual model from stakeholders in both the health science and information science domains; (5) aligning a conceptual model with an appropriate research plan; (6) adapting a conceptual model in response to new knowledge over time; and (7) disseminating conceptual models in scholarly and scientific forums. Conclusions Making explicit the conceptual model that underpins a health informatics research project can contribute to increasing the number of well-formed and strongly grounded health informatics research projects. This explication has distinct benefits for researchers in training, research teams, and researchers and practitioners in information, health, and other

  13. Conceptual Model of Quantities, Units, Dimensions, and Values

    NASA Technical Reports Server (NTRS)

    Rouquette, Nicolas F.; DeKoenig, Hans-Peter; Burkhart, Roger; Espinoza, Huascar

    2011-01-01

    JPL collaborated with experts from industry and other organizations to develop a conceptual model of quantities, units, dimensions, and values based on the current work of the ISO 80000 committee revising the International System of Units & Quantities based on the International Vocabulary of Metrology (VIM). By providing support for ISO 80000 in SysML via the International Vocabulary of Metrology (VIM), this conceptual model provides, for the first time, a standard-based approach for addressing issues of unit coherence and dimensional analysis into the practice of systems engineering with SysML-based tools. This conceptual model provides support for two kinds of analyses specified in the International Vocabulary of Metrology (VIM): coherence of units as well as of systems of units, and dimension analysis of systems of quantities. To provide a solid and stable foundation, the model for defining quantities, units, dimensions, and values in SysML is explicitly based on the concepts defined in VIM. At the same time, the model library is designed in such a way that extensions to the ISQ (International System of Quantities) and SI Units (Systeme International d Unites) can be represented, as well as any alternative systems of quantities and units. The model library can be used to support SysML user models in various ways. A simple approach is to define and document libraries of reusable systems of units and quantities for reuse across multiple projects, and to link units and quantity kinds from these libraries to Unit and QuantityKind stereotypes defined in SysML user models.

  14. Life cycle cost modeling of conceptual space vehicles

    NASA Technical Reports Server (NTRS)

    Ebeling, Charles

    1993-01-01

    This paper documents progress to date by the University of Dayton on the development of a life cycle cost model for use during the conceptual design of new launch vehicles and spacecraft. This research is being conducted under NASA Research Grant NAG-1-1327. This research effort changes the focus from that of the first two years in which a reliability and maintainability model was developed to the initial development of a life cycle cost model. Cost categories are initially patterned after NASA's three axis work breakdown structure consisting of a configuration axis (vehicle), a function axis, and a cost axis. The focus will be on operations and maintenance costs and other recurring costs. Secondary tasks performed concurrent with the development of the life cycle costing model include continual support and upgrade of the R&M model. The primary result of the completed research will be a methodology and a computer implementation of the methodology to provide for timely cost analysis in support of the conceptual design activities. The major objectives of this research are: to obtain and to develop improved methods for estimating manpower, spares, software and hardware costs, facilities costs, and other cost categories as identified by NASA personnel; to construct a life cycle cost model of a space transportation system for budget exercises and performance-cost trade-off analysis during the conceptual and development stages; to continue to support modifications and enhancements to the R&M model; and to continue to assist in the development of a simulation model to provide an integrated view of the operations and support of the proposed system.

  15. Integrating O/S models during conceptual design, part 1

    NASA Technical Reports Server (NTRS)

    Ebeling, Charles E.

    1994-01-01

    The University of Dayton is pleased to submit this report to the National Aeronautics and Space Administration (NASA), Langley Research Center, which integrates a set of models for determining operational capabilities and support requirements during the conceptual design of proposed space systems. This research provides for the integration of the reliability and maintainability (R&M) model, both new and existing simulation models, and existing operations and support (O&S) costing equations in arriving at a complete analysis methodology. Details concerning the R&M model and the O&S costing model may be found in previous reports accomplished under this grant (NASA Research Grant NAG1-1327). In the process of developing this comprehensive analysis approach, significant enhancements were made to the R&M model, updates to the O&S costing model were accomplished, and a new simulation model developed. This is the 1st part of a 3 part technical report.

  16. Misrepresentation and amendment of soil moisture in conceptual hydrological modelling

    NASA Astrophysics Data System (ADS)

    Zhuo, Lu; Han, Dawei

    2016-04-01

    Although many conceptual models are very effective in simulating river runoff, their soil moisture schemes are generally not realistic in comparison with the reality (i.e., getting the right answers for the wrong reasons). This study reveals two significant misrepresentations in those models through a case study using the Xinanjiang model which is representative of many well-known conceptual hydrological models. The first is the setting of the upper limit of its soil moisture at the field capacity, due to the 'holding excess runoff' concept (i.e., runoff begins on repletion of its storage to the field capacity). The second is neglect of capillary rise of water movement. A new scheme is therefore proposed to overcome those two issues. The amended model is as effective as its original form in flow modelling, but represents more logically realistic soil water processes. The purpose of the study is to enable the hydrological model to get the right answers for the right reasons. Therefore, the new model structure has a better capability in potentially assimilating soil moisture observations to enhance its real-time flood forecasting accuracy. The new scheme is evaluated in the Pontiac catchment of the USA through a comparison with satellite observed soil moisture. The correlation between the XAJ and the observed soil moisture is enhanced significantly from 0.64 to 0.70. In addition, a new soil moisture term called SMDS (Soil Moisture Deficit to Saturation) is proposed to complement the conventional SMD (Soil Moisture Deficit).

  17. Design Oriented Structural Modeling for Airplane Conceptual Design Optimization

    NASA Technical Reports Server (NTRS)

    Livne, Eli

    1999-01-01

    The main goal for research conducted with the support of this grant was to develop design oriented structural optimization methods for the conceptual design of airplanes. Traditionally in conceptual design airframe weight is estimated based on statistical equations developed over years of fitting airplane weight data in data bases of similar existing air- planes. Utilization of such regression equations for the design of new airplanes can be justified only if the new air-planes use structural technology similar to the technology on the airplanes in those weight data bases. If any new structural technology is to be pursued or any new unconventional configurations designed the statistical weight equations cannot be used. In such cases any structural weight estimation must be based on rigorous "physics based" structural analysis and optimization of the airframes under consideration. Work under this grant progressed to explore airframe design-oriented structural optimization techniques along two lines of research: methods based on "fast" design oriented finite element technology and methods based on equivalent plate / equivalent shell models of airframes, in which the vehicle is modelled as an assembly of plate and shell components, each simulating a lifting surface or nacelle / fuselage pieces. Since response to changes in geometry are essential in conceptual design of airplanes, as well as the capability to optimize the shape itself, research supported by this grant sought to develop efficient techniques for parametrization of airplane shape and sensitivity analysis with respect to shape design variables. Towards the end of the grant period a prototype automated structural analysis code designed to work with the NASA Aircraft Synthesis conceptual design code ACS= was delivered to NASA Ames.

  18. Operations and support cost modeling of conceptual space vehicles

    NASA Technical Reports Server (NTRS)

    Ebeling, Charles

    1994-01-01

    The University of Dayton is pleased to submit this annual report to the National Aeronautics and Space Administration (NASA) Langley Research Center which documents the development of an operations and support (O&S) cost model as part of a larger life cycle cost (LCC) structure. It is intended for use during the conceptual design of new launch vehicles and spacecraft. This research is being conducted under NASA Research Grant NAG-1-1327. This research effort changes the focus from that of the first two years in which a reliability and maintainability model was developed to the initial development of an operations and support life cycle cost model. Cost categories were initially patterned after NASA's three axis work breakdown structure consisting of a configuration axis (vehicle), a function axis, and a cost axis. A revised cost element structure (CES), which is currently under study by NASA, was used to established the basic cost elements used in the model. While the focus of the effort was on operations and maintenance costs and other recurring costs, the computerized model allowed for other cost categories such as RDT&E and production costs to be addressed. Secondary tasks performed concurrent with the development of the costing model included support and upgrades to the reliability and maintainability (R&M) model. The primary result of the current research has been a methodology and a computer implementation of the methodology to provide for timely operations and support cost analysis during the conceptual design activities.

  19. Conceptual Modeling in the Time of the Revolution: Part II

    NASA Astrophysics Data System (ADS)

    Mylopoulos, John

    Conceptual Modeling was a marginal research topic at the very fringes of Computer Science in the 60s and 70s, when the discipline was dominated by topics focusing on programs, systems and hardware architectures. Over the years, however, the field has moved to centre stage and has come to claim a central role both in Computer Science research and practice in diverse areas, such as Software Engineering, Databases, Information Systems, the Semantic Web, Business Process Management, Service-Oriented Computing, Multi-Agent Systems, Knowledge Management, and more. The transformation was greatly aided by the adoption of standards in modeling languages (e.g., UML), and model-based methodologies (e.g., Model-Driven Architectures) by the Object Management Group (OMG) and other standards organizations. We briefly review the history of the field over the past 40 years, focusing on the evolution of key ideas. We then note some open challenges and report on-going research, covering topics such as the representation of variability in conceptual models, capturing model intentions, and models of laws.

  20. Conceptual Model of the Klamath Falls, Oregon Geothermal Area

    SciTech Connect

    Prucha, R.H.; Benson, S.M.; Witherspoon, P.A.

    1987-01-20

    Over the last 50 years significant amounts of data have been obtained from the Klamath Falls geothermal resource. To date, the complexity of the system has stymied researchers, leading to the development of only very generalized hydrogeologic and geothermal models of the area. Recently, the large quantity of available temperature data have been re-evaluated, revealing new information on subsurface heat flow and locations of faults in the system. These inferences are supported by borehole, geochemical, geophysical, and hydrologic data. Based on re-evaluation of all available data, a detailed conceptual model for the Klamath Falls geothermal resource is proposed. 1 tab., 8 figs., 21 refs.

  1. A Conceptual Model of the Pasadena Housing System

    NASA Technical Reports Server (NTRS)

    Hirshberg, Alan S.; Barber, Thomas A.

    1971-01-01

    During the last 5 years, there have been several attempts at applying systems analysis to complex urban problems. This paper describes one such attempt by a multidisciplinary team of students, engineers, professors, and community representatives. The Project organization is discussed and the interaction of the different disciplines (the process) described. The two fundamental analysis questions posed by the Project were: "Why do houses deteriorate?" and "Why do people move?" The analysis of these questions led to the development of a conceptual system model of housing in Pasadena. The major elements of this model are described, and several conclusions drawn from it are presented.

  2. Conceptual model of the Klamath Falls, Oregon geothermal area

    SciTech Connect

    Prucha, R.H.; Benson, S.M.; Witherspoon, P.A.

    1987-01-01

    Over the last 50 years significant amounts of data have been obtained from the Klamath Falls geothermal resource. To date, the complexity of the system has stymied researchers, leading to the development of only very generalized hydrogeologic and geothermal models of the area. Recently, the large quantity of available temperature data have been re-evaluated, revealing new information on subsurface heat flow and locations of faults in the system. These inferences are supported by borehole, geochemical, geophysical, and hydrologic data. Based on re-evaluation of all available data, a detailed conceptual model for the Klamath Falls geothermal resource is proposed.

  3. Multimorbidity: conceptual basis, epidemiological models and measurement challenges.

    PubMed

    Fernández-Niño, Julián Alfredo; Bustos-Vázquez, Eduardo

    2016-01-01

    The growing number of patients with complex clinical profiles related to chronic diseases has contributed to the increasingly widespread use of the term 'multimorbidity'. A suitable measurement of this condition is essential to epidemiological studies considering that it represents a challenge for the clinical management of patients as well as for health systems and epidemiological investigations. In this context, the present essay reviews the conceptual proposals behind the measurement of multimorbidity including the epidemiological and methodological challenges it involves. We discuss classical definitions of comorbidity, how they differ from the concept of multimorbidity, and their roles in epidemiological studies. The various conceptual models that contribute to the operational definitions and strategies to measure this variable are also presented. The discussion enabled us to identify a significant gap between the modern conceptual development of multimorbidity and the operational definitions. This gap exists despite the theoretical developments that have occurred in the classical concept of comorbidity to arrive to the modern and multidimensional conception of multimorbidty. Measurement strategies, however, have not kept pace with this advance. Therefore, new methodological proposals need to be developed in order to obtain information regarding the actual impact on individuals' health and its implications for public health. PMID:27622480

  4. Development and testing of conceptual models describing plutonium subsurface transport (Invited)

    NASA Astrophysics Data System (ADS)

    Powell, B. A.

    2009-12-01

    Understanding coupled chemical, physical, and biological processes controlling plutonium subsurface transport is fundamental to predicting the fate and transport of actinides in the subsurface. In previous conceptual models of plutonium transport, it is assumed that low solubility and high affinity for mineral surfaces will limit the mobility of plutonium in the environment. However, this traditional model has been challenged based on observations of accelerated subsurface migration. Revised conceptual models developed through a combination of field scale observations and targeted laboratory experiments will be discussed in the context of two subsurface environments. Conceptual models of colloid facilitated plutonium transport in the southwestern United States will be discussed. Field observations and measurements show kilometer scale transport of plutonium. However, the identity of the colloidal fraction has not yet been confirmed. Laboratory experiments indicate that plutonium has strong interactions with smectite clays and iron oxide colloids. Interfacial modeling of plutonium interactions with smectite indicate that sorption of plutonium occurs through both ion exchange and surface complexation mechanisms. Batch, column, and batch flow-through experiments examining plutonium interactions with metal (oxyhydr)oxide minerals indicate strong sorption hysteresis which is believed to be the result of plutonium reduction to more strongly sorbing oxidation states as well as dehydration of the plutonium ion upon formation of a surface complex. Furthermore, nanoscale plutonium hydrous oxide colloids also appear to have strong interactions with iron oxide colloids. These data aid in the validation of the observed kilometer scale transport of plutonium in subsurface environments. A second set of long-term experiments have focused on vadoze zone transport of plutonium at the Savannah River Site in the southeastern United States. Based on a series of batch and column studies

  5. Conceptual Change Texts in Chemistry Teaching: A Study on the Particle Model of Matter

    ERIC Educational Resources Information Center

    Beerenwinkel, Anne; Parchmann, Ilka; Grasel, Cornelia

    2011-01-01

    This study explores the effect of a conceptual change text on students' awareness of common misconceptions on the particle model of matter. The conceptual change text was designed based on principles of text comprehensibility, of conceptual change instruction and of instructional approaches how to introduce the particle model. It was evaluated in…

  6. A Conceptual Framework for SAHRA Integrated Multi-resolution Modeling in the Rio Grande Basin

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Gupta, H.; Springer, E.; Wagener, T.; Brookshire, D.; Duffy, C.

    2004-12-01

    The sustainable management of water resources in a river basin requires an integrated analysis of the social, economic, environmental and institutional dimensions of the problem. Numerical models are commonly used for integration of these dimensions and for communication of the analysis results to stakeholders and policy makers. The National Science Foundation Science and Technology Center for Sustainability of semi-Arid Hydrology and Riparian Areas (SAHRA) has been developing integrated multi-resolution models to assess impacts of climate variability and land use change on water resources in the Rio Grande Basin. These models not only couple natural systems such as surface and ground waters, but will also include engineering, economic and social components that may be involved in water resources decision-making processes. This presentation will describe the conceptual framework being developed by SAHRA to guide and focus the multiple modeling efforts and to assist the modeling team in planning, data collection and interpretation, communication, evaluation, etc. One of the major components of this conceptual framework is a Conceptual Site Model (CSM), which describes the basin and its environment based on existing knowledge and identifies what additional information must be collected to develop technically sound models at various resolutions. The initial CSM is based on analyses of basin profile information that has been collected, including a physical profile (e.g., topographic and vegetative features), a man-made facility profile (e.g., dams, diversions, and pumping stations), and a land use and ecological profile (e.g., demographics, natural habitats, and endangered species). Based on the initial CSM, a Conceptual Physical Model (CPM) is developed to guide and evaluate the selection of a model code (or numerical model) for each resolution to conduct simulations and predictions. A CPM identifies, conceptually, all the physical processes and engineering and socio

  7. Our evolving conceptual model of the coastal eutrophication problem

    USGS Publications Warehouse

    Cloern, James E.

    2001-01-01

    A primary focus of coastal science during the past 3 decades has been the question: How does anthropogenic nutrient enrichment cause change in the structure or function of nearshore coastal ecosystems? This theme of environmental science is recent, so our conceptual model of the coastal eutrophication problem continues to change rapidly. In this review, I suggest that the early (Phase I) conceptual model was strongly influenced by limnologists, who began intense study of lake eutrophication by the 1960s. The Phase I model emphasized changing nutrient input as a signal, and responses to that signal as increased phytoplankton biomass and primary production, decomposition of phytoplankton-derived organic matter, and enhanced depletion of oxygen from bottom waters. Coastal research in recent decades has identified key differences in the responses of lakes and coastal-estuarine ecosystems to nutrient enrichment. The contemporary (Phase II) conceptual model reflects those differences and includes explicit recognition of (1) system-specific attributes that act as a filter to modulate the responses to enrichment (leading to large differences among estuarine-coastal systems in their sensitivity to nutrient enrichment); and (2) a complex suite of direct and indirect responses including linked changes in: water transparency, distribution of vascular plants and biomass of macroalgae, sediment biogeochemistry and nutrient cycling, nutrient ratios and their regulation of phytoplankton community composition, frequency of toxic/harmful algal blooms, habitat quality for metazoans, reproduction/growth/survival of pelagic and benthic invertebrates, and subtle changes such as shifts in the seasonality of ecosystem functions. Each aspect of the Phase II model is illustrated here with examples from coastal ecosystems around the world. In the last section of this review I present one vision of the next (Phase III) stage in the evolution of our conceptual model, organized around 5

  8. Development and Validation of a Mass Casualty Conceptual Model

    PubMed Central

    Culley, Joan M.; Effken, Judith A.

    2012-01-01

    Purpose To develop and validate a conceptual model that provides a framework for the development and evaluation of information systems for mass casualty events. Design The model was designed based on extant literature and existing theoretical models. A purposeful sample of 18 experts validated the model. Open-ended questions, as well as a 7-point Likert scale, were used to measure expert consensus on the importance of each construct and its relationship in the model and the usefulness of the model to future research. Methods Computer-mediated applications were used to facilitate a modified Delphi technique through which a panel of experts provided validation for the conceptual model. Rounds of questions continued until consensus was reached, as measured by an interquartile range (no more than 1 scale point for each item); stability (change in the distribution of responses less than 15% between rounds); and percent agreement (70% or greater) for indicator questions. Findings Two rounds of the Delphi process were needed to satisfy the criteria for consensus or stability related to the constructs, relationships, and indicators in the model. The panel reached consensus or sufficient stability to retain all 10 constructs, 9 relationships, and 39 of 44 indicators. Experts viewed the model as useful (mean of 5.3 on a 7-point scale). Conclusions Validation of the model provides the first step in understanding the context in which mass casualty events take place and identifying variables that impact outcomes of care. Clinical Relevance This study provides a foundation for understanding the complexity of mass casualty care, the roles that nurses play in mass casualty events, and factors that must be considered in designing and evaluating information-communication systems to support effective triage under these conditions. PMID:20487188

  9. Equivalent plate modeling for conceptual design of aircraft wing structures

    NASA Technical Reports Server (NTRS)

    Giles, Gary L.

    1995-01-01

    This paper describes an analysis method that generates conceptual-level design data for aircraft wing structures. A key requirement is that this data must be produced in a timely manner so that is can be used effectively by multidisciplinary synthesis codes for performing systems studies. Such a capability is being developed by enhancing an equivalent plate structural analysis computer code to provide a more comprehensive, robust and user-friendly analysis tool. The paper focuses on recent enhancements to the Equivalent Laminated Plate Solution (ELAPS) analysis code that significantly expands the modeling capability and improves the accuracy of results. Modeling additions include use of out-of-plane plate segments for representing winglets and advanced wing concepts such as C-wings along with a new capability for modeling the internal rib and spar structure. The accuracy of calculated results is improved by including transverse shear effects in the formulation and by using multiple sets of assumed displacement functions in the analysis. Typical results are presented to demonstrate these new features. Example configurations include a C-wing transport aircraft, a representative fighter wing and a blended-wing-body transport. These applications are intended to demonstrate and quantify the benefits of using equivalent plate modeling of wing structures during conceptual design.

  10. Conceptual Models as Hypotheses in Monitoring Urban Landscapes

    NASA Astrophysics Data System (ADS)

    Lookingbill, Todd R.; Gardner, Robert H.; Townsend, Philip A.; Carter, Shawn L.

    2007-08-01

    Many problems and challenges of ecosystem management currently are driven by the rapid pace and spatial extent of landscape change. Parks and reserves within areas of high human population density are especially challenged to meet the recreational needs of local populations and to preserve valued environmental resources. The complex problem of managing multiple objectives and multiple resources requires an enormous quantity of information, and conceptual models have been proposed as tools for organizing and interpreting this information. Academics generally prefer a bottom-up approach to model construction that emphasizes ecologic theory and process, whereas managers often use a top-down approach that takes advantage of existing information to address more pragmatic objectives. The authors propose a formal process for developing, applying, and testing conceptual models to be used in landscape monitoring that reconciles these seemingly opposing perspectives. The four-step process embraces the role of hypothesis testing in the development of models and evaluation of their utility. An example application of the process to a network of national parks in and around Washington, DC illustrates the ability of the approach to systematically identify monitoring data that would both advance ecologic theory and inform management decisions.

  11. Conceptual models as hypotheses in monitoring urban landscapes.

    PubMed

    Lookingbill, Todd R; Gardner, Robert H; Townsend, Philip A; Carter, Shawn L

    2007-08-01

    Many problems and challenges of ecosystem management currently are driven by the rapid pace and spatial extent of landscape change. Parks and reserves within areas of high human population density are especially challenged to meet the recreational needs of local populations and to preserve valued environmental resources. The complex problem of managing multiple objectives and multiple resources requires an enormous quantity of information, and conceptual models have been proposed as tools for organizing and interpreting this information. Academics generally prefer a bottom-up approach to model construction that emphasizes ecologic theory and process, whereas managers often use a top-down approach that takes advantage of existing information to address more pragmatic objectives. The authors propose a formal process for developing, applying, and testing conceptual models to be used in landscape monitoring that reconciles these seemingly opposing perspectives. The four-step process embraces the role of hypothesis testing in the development of models and evaluation of their utility. An example application of the process to a network of national parks in and around Washington, DC illustrates the ability of the approach to systematically identify monitoring data that would both advance ecologic theory and inform management decisions. PMID:17562105

  12. Ecohydrologic Response of a Wetland Indicator Species to Climate Change and Streamflow Regulation: A Conceptual Model

    NASA Astrophysics Data System (ADS)

    Ward, E. M.; Gorelick, S.

    2015-12-01

    The Peace-Athabasca Delta ("Delta") in northeastern Alberta, Canada, is a UNESCO World Heritage Site and a Ramsar Wetland of International Importance. Delta ecohydrology is expected to respond rapidly to upstream water demand and climate change, with earlier spring meltwater, decreased springtime peak flow, and a decline in springtime ice-jam flooding. We focus on changes in the population and distribution of muskrat (Ondatra zibethicus), an ecohydrologic indicator species. We present a conceptual model linking hydrology and muskrat ecology. Our conceptual model links seven modules representing (1) upstream water demand, (2) streamflow and snowmelt, (3) floods, (4) the water balance of floodplain lakes, (5) muskrat habitat suitability, (6) wetland vegetation, and (7) muskrat population dynamics predicted using an agent-based model. Our goal is to evaluate the effects of different climate change and upstream water demand scenarios on the abundance and distribution of Delta muskrat, from present-2100. Moving from the current conceptual model to a predictive quantitative model, we will rely on abundant existing data and Traditional Ecological Knowledge of muskrat and hydrology in the Delta.

  13. Conceptual Modeling for the Unified Medical Language System

    PubMed Central

    Barr, Charles E.; Komorowski, Henryk Jan; Pattison-Gordon, Edward; Greenes, Robert A.

    1988-01-01

    The Unified Medical Language System was proposed by the National Library of Medicine to facilitate the exchange and utilization of information from multiple sources. We are using semantic networks as the knowledge representation scheme in a prototype system to explore how to accomplish these goals. Conceptual modeling helps define a complete and consistent set of objects and relationships to include in the semantic net. Both top-down and bottom-up approaches were found useful in the seven step process of building the semantic network. Theoretical and practical issues are discussed as well as future extensions to the current prototype.

  14. Conceptual Modeling of mRNA Decay Provokes New Hypotheses

    PubMed Central

    Somekh, Judith; Haimovich, Gal; Guterman, Adi; Dori, Dov; Choder, Mordechai

    2014-01-01

    Biologists are required to integrate large amounts of data to construct a working model of the system under investigation. This model is often informal and stored mentally or textually, making it prone to contain undetected inconsistencies, inaccuracies, or even contradictions, not much less than a representation in free natural language. Using Object-Process Methodology (OPM), a formal yet visual and humanly accessible conceptual modeling language, we have created an executable working model of the mRNA decay process in Saccharomyces cerevisiae, as well as the import of its components to the nucleus following mRNA decay. We show how our model, which incorporates knowledge from 43 articles, can reproduce outcomes that match the experimental findings, evaluate hypotheses, and predict new possible outcomes. Moreover, we were able to analyze the effects of the mRNA decay model perturbations related to gene and interaction deletions, and predict the nuclear import of certain decay factors, which we then verified experimentally. In particular, we verified experimentally the hypothesis that Rpb4p, Lsm1p, and Pan2p remain bound to the RNA 3′-untralslated region during the entire process of the 5′ to 3′ degradation of the RNA open reading frame. The model has also highlighted erroneous hypotheses that indeed were not in line with the experimental outcomes. Beyond the scientific value of these specific findings, this work demonstrates the value of the conceptual model as an in silico vehicle for hypotheses generation and testing, which can reinforce, and often even replace, risky, costlier wet lab experiments. PMID:25255440

  15. Empirical evaluation of the conceptual model underpinning a regional aquatic long-term monitoring program using causal modelling

    USGS Publications Warehouse

    Irvine, Kathryn M.; Miller, Scott; Al-Chokhachy, Robert K.; Archer, Erik; Roper, Brett B.; Kershner, Jeffrey L.

    2015-01-01

    Conceptual models are an integral facet of long-term monitoring programs. Proposed linkages between drivers, stressors, and ecological indicators are identified within the conceptual model of most mandated programs. We empirically evaluate a conceptual model developed for a regional aquatic and riparian monitoring program using causal models (i.e., Bayesian path analysis). We assess whether data gathered for regional status and trend estimation can also provide insights on why a stream may deviate from reference conditions. We target the hypothesized causal pathways for how anthropogenic drivers of road density, percent grazing, and percent forest within a catchment affect instream biological condition. We found instream temperature and fine sediments in arid sites and only fine sediments in mesic sites accounted for a significant portion of the maximum possible variation explainable in biological condition among managed sites. However, the biological significance of the direct effects of anthropogenic drivers on instream temperature and fine sediments were minimal or not detected. Consequently, there was weak to no biological support for causal pathways related to anthropogenic drivers’ impact on biological condition. With weak biological and statistical effect sizes, ignoring environmental contextual variables and covariates that explain natural heterogeneity would have resulted in no evidence of human impacts on biological integrity in some instances. For programs targeting the effects of anthropogenic activities, it is imperative to identify both land use practices and mechanisms that have led to degraded conditions (i.e., moving beyond simple status and trend estimation). Our empirical evaluation of the conceptual model underpinning the long-term monitoring program provided an opportunity for learning and, consequently, we discuss survey design elements that require modification to achieve question driven monitoring, a necessary step in the practice of

  16. Evolution of the conceptual model of unsaturated zone hydrology at Yucca Mountain, Nevada

    NASA Astrophysics Data System (ADS)

    Flint, Alan L.; Flint, Lorraine E.; Bodvarsson, Gudmundur S.; Kwicklis, Edward M.; Fabryka-Martin, June

    2001-06-01

    Yucca Mountain is an arid site proposed for consideration as the United States' first underground high-level radioactive waste repository. Low rainfall (approximately 170 mm/yr) and a thick unsaturated zone (500-1000 m) are important physical attributes of the site because the quantity of water likely to reach the waste and the paths and rates of movement of the water to the saturated zone under future climates would be major factors in controlling the concentrations and times of arrival of radionuclides at the surrounding accessible environment. The framework for understanding the hydrologic processes that occur at this site and that control how quickly water will penetrate through the unsaturated zone to the water table has evolved during the past 15 yr. Early conceptual models assumed that very small volumes of water infiltrated into the bedrock (0.5-4.5 mm/yr, or 2-3 percent of rainfall), that much of the infiltrated water flowed laterally within the upper nonwelded units because of capillary barrier effects, and that the remaining water flowed down faults with a small amount flowing through the matrix of the lower welded, fractured rocks. It was believed that the matrix had to be saturated for fractures to flow. However, accumulating evidence indicated that infiltration rates were higher than initially estimated, such as infiltration modeling based on neutron borehole data, bomb-pulse isotopes deep in the mountain, perched water analyses and thermal analyses. Mechanisms supporting lateral diversion did not apply at these higher fluxes, and the flux calculated in the lower welded unit exceeded the conductivity of the matrix, implying vertical flow of water in the high permeability fractures of the potential repository host rock, and disequilibrium between matrix and fracture water potentials. The development of numerical modeling methods and parameter values evolved concurrently with the conceptual model in order to account for the observed field data

  17. Evolution of the conceptual model of unsaturated zone hydrology at yucca mountain, nevada

    SciTech Connect

    Flint, A. L.; Flint, L. E.; Bodvarsson, G. S.; Kwicklis, E. M.; Fabryka-Martin, J.

    2001-02-01

    Yucca Mountain is an arid site proposed for consideration as the United States' first underground high-level radioactive waste repository. Low rainfall (approximately 170 mm/yr) and a thick unsaturated zone (500-1000 m) are important physical attributes of the site because the quantity of water likely to reach the waste and the paths and rates of movement of the water to the saturated zone under future climates would be major factors in controlling the concentrations and times of arrival of radionuclides at the surrounding accessible environment. The framework for understanding the hydrologic processes that occur at this site and that control how quickly water will penetrate through the unsaturated zone to the water table has evolved during the past 15 yr. Early conceptual models assumed that very small volumes of water infiltrated into the bedrock (0.5-4.5 mm/yr, or 2-3 percent of rainfall), that much of the infiltrated water flowed laterally within the upper nonwelded units because o f capillary barrier effects, and that the remaining water flowed down faults with a small amount flowing through the matrix of the lower welded, fractured rocks. It was believed that the matrix had to be saturated for fractures to show. However, accumulating evidence indicated that infiltration rates were higher than initially estimated, such as infiltration modeling based on neutron borehole data, bomb-pulse isotopes deep in the mountain, perched water analyses and thermal analyses. Mechanisms supporting lateral diversion did not apply at these higher fluxes, and the flux calculated in the lower welded unit exceeded the conductivity of the matrix, implying vertical flow of water into the high permeability fractures of the potential repository host rock, and disequilibrium between matrix and fracture water potentials. The development of numerical modeling methods and parameter values evolved concurrently with the conceptual model in order to account for the observed field data

  18. Evolution of the conceptual model of unsaturated zone hydrology at Yucca Mountain, Nevada

    USGS Publications Warehouse

    Flint, Alan L.; Flint, Lorraine E.; Bodvarsson, Gudmundur S.; Kwicklis, Edward M.; Fabryka-Martin, June

    2001-01-01

    Yucca Mountain is an arid site proposed for consideration as the United States’ first underground high-level radioactive waste repository. Low rainfall (approximately 170 mm/yr) and a thick unsaturated zone (500–1000 m) are important physical attributes of the site because the quantity of water likely to reach the waste and the paths and rates of movement of the water to the saturated zone under future climates would be major factors in controlling the concentrations and times of arrival of radionuclides at the surrounding accessible environment. The framework for understanding the hydrologic processes that occur at this site and that control how quickly water will penetrate through the unsaturated zone to the water table has evolved during the past 15 yr. Early conceptual models assumed that very small volumes of water infiltrated into the bedrock (0.5–4.5 mm/yr, or 2–3 percent of rainfall), that much of the infiltrated water flowed laterally within the upper nonwelded units because of capillary barrier effects, and that the remaining water flowed down faults with a small amount flowing through the matrix of the lower welded, fractured rocks. It was believed that the matrix had to be saturated for fractures to flow. However, accumulating evidence indicated that infiltration rates were higher than initially estimated, such as infiltration modeling based on neutron borehole data, bomb-pulse isotopes deep in the mountain, perched water analyses and thermal analyses. Mechanisms supporting lateral diversion did not apply at these higher fluxes, and the flux calculated in the lower welded unit exceeded the conductivity of the matrix, implying vertical flow of water in the high permeability fractures of the potential repository host rock, and disequilibrium between matrix and fracture water potentials. The development of numerical modeling methods and parameter values evolved concurrently with the conceptual model in order to account for the observed field data

  19. Conceptual Understanding of Climate Change with a Simple Climate Model

    NASA Astrophysics Data System (ADS)

    Dommenget, Dietmar; Floeter, Janine

    2010-05-01

    The future climate change projections are essentially based on coupled general circulation model (CGCM) simulations, which give a distinct global warming pattern with arctic winter amplification, an equilibrium land-sea warming contrast and an inter-hemispheric warming gradient. While these simulations are the most important tool of the Intergovernmental Panel on Climate Change (IPCC) predictions, the conceptual understanding of these predicted structures of climate change and the causes of their uncertainties is very difficult to reach if only based on these highly complex CGCM simulations. In the study presented here we will introduce a very simple, globally resolved energy balance (GREB) model, which is capable of simulating the main characteristics of global warming. The model shall give a bridge between the strongly simplified energy balance models and the fully coupled 4-dimensional complex CGCMs. It provides a fast tool for the conceptual understanding and development of hypotheses for climate change studies and teaching. It is based on the surface energy balance by very simple representations of solar and thermal radiation, the atmospheric hydrological cycle, sensible turbulent heat flux, the transport by the mean atmospheric circulation and heat exchange with the deeper ocean. It can be run on any PC computer and compute 200yrs climate scenarios within minutes. The simple model's climate sensitivity and the spatial structure of the warming pattern are within the uncertainties of the IPCC models simulations. It is capable of simulating the arctic winter amplification, the equilibrium land-sea warming contrast and the inter-hemispheric warming gradient with good agreement to the IPCC models in amplitude and structure.

  20. Conceptual Design Report: Nevada Test Site Mixed Waste Disposal Facility Project

    SciTech Connect

    NSTec Environmental Management

    2009-01-31

    Environmental cleanup of contaminated nuclear weapons manufacturing and test sites generates radioactive waste that must be disposed. Site cleanup activities throughout the U.S. Department of Energy (DOE) complex are projected to continue through 2050. Some of this waste is mixed waste (MW), containing both hazardous and radioactive components. In addition, there is a need for MW disposal from other mission activities. The Waste Management Programmatic Environmental Impact Statement Record of Decision designates the Nevada Test Site (NTS) as a regional MW disposal site. The NTS has a facility that is permitted to dispose of onsite- and offsite-generated MW until November 30, 2010. There is not a DOE waste management facility that is currently permitted to dispose of offsite-generated MW after 2010, jeopardizing the DOE environmental cleanup mission and other MW-generating mission-related activities. A mission needs document (CD-0) has been prepared for a newly permitted MW disposal facility at the NTS that would provide the needed capability to support DOE's environmental cleanup mission and other MW-generating mission-related activities. This report presents a conceptual engineering design for a MW facility that is fully compliant with Resource Conservation and Recovery Act (RCRA) and DOE O 435.1, 'Radioactive Waste Management'. The facility, which will be located within the Area 5 Radioactive Waste Management Site (RWMS) at the NTS, will provide an approximately 20,000-cubic yard waste disposal capacity. The facility will be licensed by the Nevada Division of Environmental Protection (NDEP).

  1. An analogue conceptual rainfall-runoff model for educational purposes

    NASA Astrophysics Data System (ADS)

    Herrnegger, Mathew; Riedl, Michael; Schulz, Karsten

    2016-04-01

    Conceptual rainfall-runoff models, in which runoff processes are modelled with a series of connected linear and non-linear reservoirs, remain widely applied tools in science and practice. Additionally, the concept is appreciated in teaching due to its somewhat simplicity in explaining and exploring hydrological processes of catchments. However, when a series of reservoirs are used, the model system becomes highly parametrized and complex and the traceability of the model results becomes more difficult to explain to an audience not accustomed to numerical modelling. Since normally the simulations are performed with a not visible digital code, the results are also not easily comprehensible. This contribution therefore presents a liquid analogue model, in which a conceptual rainfall-runoff model is reproduced by a physical model. This consists of different acrylic glass containers representing different storage components within a catchment, e.g. soil water or groundwater storage. The containers are equipped and connected with pipes, in which water movement represents different flow processes, e.g. surface runoff, percolation or base flow. Water from a storage container is pumped to the upper part of the model and represents effective rainfall input. The water then flows by gravity through the different pipes and storages. Valves are used for controlling the flows within the analogue model, comparable to the parameterization procedure in numerical models. Additionally, an inexpensive microcontroller-based board and sensors are used to measure storage water levels, with online visualization of the states as time series data, building a bridge between the analogue and digital world. The ability to physically witness the different flows and water levels in the storages makes the analogue model attractive to the audience. Hands-on experiments can be performed with students, in which different scenarios or catchment types can be simulated, not only with the analogue but

  2. Development of a conceptual model of cancer caregiver health literacy.

    PubMed

    Yuen, E Y N; Dodson, S; Batterham, R W; Knight, T; Chirgwin, J; Livingston, P M

    2016-03-01

    Caregivers play a vital role in caring for people diagnosed with cancer. However, little is understood about caregivers' capacity to find, understand, appraise and use information to improve health outcomes. The study aimed to develop a conceptual model that describes the elements of cancer caregiver health literacy. Six concept mapping workshops were conducted with 13 caregivers, 13 people with cancer and 11 healthcare providers/policymakers. An iterative, mixed methods approach was used to analyse and synthesise workshop data and to generate the conceptual model. Six major themes and 17 subthemes were identified from 279 statements generated by participants during concept mapping workshops. Major themes included: access to information, understanding of information, relationship with healthcare providers, relationship with the care recipient, managing challenges of caregiving and support systems. The study extends conceptualisations of health literacy by identifying factors specific to caregiving within the cancer context. The findings demonstrate that caregiver health literacy is multidimensional, includes a broad range of individual and interpersonal elements, and is influenced by broader healthcare system and community factors. These results provide guidance for the development of: caregiver health literacy measurement tools; strategies for improving health service delivery, and; interventions to improve caregiver health literacy. PMID:25630765

  3. A conceptual model of people's vulnerability to floods

    NASA Astrophysics Data System (ADS)

    Milanesi, Luca; Pilotti, Marco; Ranzi, Roberto

    2015-01-01

    Hydraulic risk maps provide the baseline for land use and emergency planning. Accordingly, they should convey clear information on the potential physical implications of the different hazards to the stakeholders. This paper presents a vulnerability criterion focused on human stability in a flow specifically devised for rapidly evolving floods where life, before than economic values, might be threatened. The human body is conceptualized as a set of cylinders and its stability to slipping and toppling is assessed by forces and moments equilibrium. Moreover, a depth threshold to consider drowning is assumed. In order to widen its scope of application, the model takes the destabilizing effect of local slope (so far disregarded in the literature) and fluid density into account. The resulting vulnerability classification could be naturally subdivided in three levels (low, medium, and high) that are limited by two stability curves for children and adults, respectively. In comparison with the most advanced literature conceptual approaches, the proposed model is weakly parameterized and the computed thresholds fit better the available experimental data sets. A code that implements the proposed algorithm is provided.

  4. Treatment of uncertainty and developing conceptual models for environmental risk assessments and radioactive waste disposal safety cases.

    PubMed

    El-Ghonemy, Hamdi; Watts, Len; Fowler, Linda

    2005-01-01

    The common approach to performing quantitative risk assessments in the contaminated land industry in the UK lacks a formal methodology for the treatment of the full range of uncertainties and for documenting decisions regarding the development of conceptual models and the selection of computer codes. The approach presented here represents an alternative, more detailed, and systematic approach for developing conceptual models and addressing uncertainties when undertaking contaminated land risk assessments. It is intended that the advantages of this approach are recognised by practitioners in the contaminated land industry and adopted, where appropriate, to help improve the quality of contaminated land risk assessments. The identification of features, events, and processes (FEPs) has been applied to safety assessments of deep geological and near-surface disposal of radioactive wastes. One of the primary benefits of using this approach is in the development of conceptual models. The approach identifies the FEPs that need to be addressed during the development of conceptual models and in the selection of suitable computer codes that can be used to represent the conceptual models. This approach has been applied by BNFL at the low-level radioactive waste disposal site at Drigg in Cumbria and is currently being adopted for a contaminated land study at the Sellafield site, also in Cumbria. This paper presents the advantages of using FEPs in the development of conceptual models and the treatment of uncertainties. The paper also discusses the application of this approach to contaminated land studies and provides an example to demonstrate the application of the approach. BNFL's approach at the Drigg site involves the identification of components (features) and phenomena (events and processes) that govern interactions and dependencies between the components by arranging them in a matrix format. PMID:15607782

  5. Simulation of shallow groundwater levels: Comparison of a data-driven and a conceptual model

    NASA Astrophysics Data System (ADS)

    Fahle, Marcus; Dietrich, Ottfried; Lischeid, Gunnar

    2015-04-01

    Despite an abundance of models aimed at simulating shallow groundwater levels, application of such models is often hampered by a lack of appropriate input data. Difficulties especially arise with regard to soil data, which are typically hard to obtain and prone to spatial variability, eventually leading to uncertainties in the model results. Modelling approaches relying entirely on easily measured quantities are therefore an alternative to encourage the applicability of models. We present and compare two models for calculating 1-day-ahead predictions of the groundwater level that are only based on measurements of potential evapotranspiration, precipitation and groundwater levels. The first model is a newly developed conceptual model that is parametrized using the White method (which estimates the actual evapotranspiration on basis of diurnal groundwater fluctuations) and a rainfall-response ratio. Inverted versions of the two latter approaches are then used to calculate the predictions of the groundwater level. Furthermore, as a completely data-driven alternative, a simple feed-forward multilayer perceptron neural network was trained based on the same inputs and outputs. Data of 4 growing periods (April to October) from a study site situated in the Spreewald wetland in North-east Germany were taken to set-up the models and compare their performance. In addition, response surfaces that relate model outputs to combinations of different input variables are used to reveal those aspects in which the two approaches coincide and those in which they differ. Finally, it will be evaluated whether the conceptual approach can be enhanced by extracting knowledge of the neural network. This is done by replacing in the conceptual model the default function that relates groundwater recharge and groundwater level, which is assumed to be linear, by the non-linear function extracted from the neural network.

  6. Importance of incorporating agriculture in conceptual rainfall-runoff models

    NASA Astrophysics Data System (ADS)

    de Boer-Euser, Tanja; Hrachowitz, Markus; Winsemius, Hessel; Savenije, Hubert

    2016-04-01

    Incorporating spatially variable information is a frequently discussed option to increase the performance of (semi-)distributed conceptual rainfall-runoff models. One of the methods to do this is by using this spatially variable information to delineate Hydrological Response Units (HRUs) within a catchment. In large parts of Europe the original forested land cover is replaced by an agricultural land cover. This change in land cover probably affects the dominant runoff processes in the area, for example by increasing the Hortonian overland flow component, especially on the flatter and higher elevated parts of the catchment. A change in runoff processes implies a change in HRUs as well. A previous version of our model distinguished wetlands (areas close to the stream) from the remainder of the catchment. However, this configuration was not able to reproduce all fast runoff processes, both in summer as in winter. Therefore, this study tests whether the reproduction of fast runoff processes can be improved by incorporating a HRU which explicitly accounts for the effect of agriculture. A case study is carried out in the Ourthe catchment in Belgium. For this case study the relevance of different process conceptualisations is tested stepwise. Among the conceptualisations are Hortonian overland flow in summer and winter, reduced infiltration capacity due to a partly frozen soil and the relative effect of rainfall and snow smelt in case of this frozen soil. The results show that the named processes can make a large difference on event basis, especially the Hortonian overland flow in summer and the combination of rainfall and snow melt on (partly) frozen soil in winter. However, differences diminish when the modelled period of several years is evaluated based on standard metrics like Nash-Sutcliffe Efficiency. These results emphasise on one hand the importance of incorporating the effects of agricultural in conceptual models and on the other hand the importance of more event

  7. Behavioral patterns and lesion sites associated with impaired processing of lexical and conceptual knowledge of actions.

    PubMed

    Kemmerer, David; Rudrauf, David; Manzel, Ken; Tranel, Daniel

    2012-07-01

    To further investigate the neural substrates of lexical and conceptual knowledge of actions, we administered a battery of six tasks to 226 brain-damaged patients with widely distributed lesions in the left and right cerebral hemispheres. The tasks probed lexical and conceptual knowledge of actions in a variety of verbal and non-verbal ways, including naming, word-picture matching, attribute judgments involving both words and pictures, and associative comparisons involving both words and pictures. Of the 226 patients who were studied, 61 failed one or more of the six tasks, with four patients being impaired on the entire battery, and varied numbers of patients being impaired on varied combinations of tasks. Overall, the 61 patients manifested a complex array of associations and dissociations across the six tasks. The lesion sites of 147 of the 226 patients were also investigated, using formal methods for lesion-deficit statistical mapping and power analysis of lesion overlap maps. Significant effects for all six tasks were found in the following left-hemisphere regions: the inferior frontal gyrus; the ventral precentral gyrus, extending superiorly into what are likely to be hand-related primary motor and premotor areas; and the anterior insula. In addition, significant effects for 4-5 tasks were found in not only the regions just mentioned, but also in several other left-hemisphere areas: the ventral postcentral gyrus; the supramarginal gyrus; and the posterior middle temporal gyrus. These results converge with previous research on the neural underpinnings of action words and concepts. However, the current study goes considerably beyond most previous investigations by providing extensive behavioral and lesion data for an unusually large and diverse sample of brain-damaged patients, and by incorporating multiple measures of verb comprehension. Regarding theoretical implications, the study provides new support for the Embodied Cognition Framework, which maintains that

  8. Conceptual Site Treatment Plan Laboratory for Energy-Related Health Research Environmental Restoration Project

    SciTech Connect

    Chapman, T.E.

    1993-10-01

    The Federal Facilities Compliance Act (the Act) of 1992 waives sovereign immunity for federal facilities for fines and penalties under the provisions of the Resource Recovery and Conservation Act, state, interstate, and local hazardous and solid waste management requirements. However, for three years the Act delays the waiver for violations involving US Department of Energy (DOE) facilities. The Act, however, requires that the DOE prepare a Conceptual Site Treatment Plan (CSTP) for each of its sites that generate or store mixed wastes (MWs). The purpose of the CSTP is to present DOE`s preliminary evaluations of the development of treatment capacities and technologies for treating a site`s MW. This CSTP presents the preliminary capacity and technology evaluation for the Laboratory for Energy-Related Health Research (LEHR). The five identified MW streams at LEHR are evaluated to the extent possible given available information. Only one MW stream is sufficiently well defined to permit a technology evaluation to be performed. Two other MW streams are in the process of being characterized so that an evaluation can be performed. The other two MW streams will be generated by the decommissioning of inactive facilities onsite within the next five years.

  9. A conceptual model for short-term inpatient group psychotherapy.

    PubMed

    Kibel, H D

    1981-01-01

    The author reviews the history of the literature on inpatient group psychotherapy. Key observations of early workers--the central role of the group leader, the experiential benefits of the group, and the relationship to the milieu--have not resulted in wide application of this form of therapy because of limitations of previous conceptual models. The model presented draws on concepts of general systems and object relations theory. General systems theory explains how the small therapy group symbolically reflects the dynamic process of the psychiatric unit. Object relations theory provides a unique understanding of the central regulatory function of the therapist and the beneficial effects of the group. The author provides clinical illustrations of these points. PMID:7446787

  10. A conceptual model for translating omic data into clinical action

    PubMed Central

    Herr, Timothy M.; Bielinski, Suzette J.; Bottinger, Erwin; Brautbar, Ariel; Brilliant, Murray; Chute, Christopher G.; Denny, Joshua; Freimuth, Robert R.; Hartzler, Andrea; Kannry, Joseph; Kohane, Isaac S.; Kullo, Iftikhar J.; Lin, Simon; Pathak, Jyotishman; Peissig, Peggy; Pulley, Jill; Ralston, James; Rasmussen, Luke; Roden, Dan; Tromp, Gerard; Williams, Marc S.; Starren, Justin

    2015-01-01

    Genomic, proteomic, epigenomic, and other “omic” data have the potential to enable precision medicine, also commonly referred to as personalized medicine. The volume and complexity of omic data are rapidly overwhelming human cognitive capacity, requiring innovative approaches to translate such data into patient care. Here, we outline a conceptual model for the application of omic data in the clinical context, called “the omic funnel.” This model parallels the classic “Data, Information, Knowledge, Wisdom pyramid” and adds context for how to move between each successive layer. Its goal is to allow informaticians, researchers, and clinicians to approach the problem of translating omic data from bench to bedside, by using discrete steps with clearly defined needs. Such an approach can facilitate the development of modular and interoperable software that can bring precision medicine into widespread practice. PMID:26430534

  11. A conceptual model for translating omic data into clinical action.

    PubMed

    Herr, Timothy M; Bielinski, Suzette J; Bottinger, Erwin; Brautbar, Ariel; Brilliant, Murray; Chute, Christopher G; Denny, Joshua; Freimuth, Robert R; Hartzler, Andrea; Kannry, Joseph; Kohane, Isaac S; Kullo, Iftikhar J; Lin, Simon; Pathak, Jyotishman; Peissig, Peggy; Pulley, Jill; Ralston, James; Rasmussen, Luke; Roden, Dan; Tromp, Gerard; Williams, Marc S; Starren, Justin

    2015-01-01

    Genomic, proteomic, epigenomic, and other "omic" data have the potential to enable precision medicine, also commonly referred to as personalized medicine. The volume and complexity of omic data are rapidly overwhelming human cognitive capacity, requiring innovative approaches to translate such data into patient care. Here, we outline a conceptual model for the application of omic data in the clinical context, called "the omic funnel." This model parallels the classic "Data, Information, Knowledge, Wisdom pyramid" and adds context for how to move between each successive layer. Its goal is to allow informaticians, researchers, and clinicians to approach the problem of translating omic data from bench to bedside, by using discrete steps with clearly defined needs. Such an approach can facilitate the development of modular and interoperable software that can bring precision medicine into widespread practice. PMID:26430534

  12. Trade-offs underlying maternal breastfeeding decisions: a conceptual model.

    PubMed

    Tully, Kristin P; Ball, Helen L

    2013-01-01

    This paper presents a new conceptual model that generates predictions about breastfeeding decisions and identifies interactions that affect outcomes. We offer a contextual approach to infant feeding that models multi-directional influences by expanding on the evolutionary parent-offspring conflict and situation-specific breastfeeding theories. The main hypothesis generated from our framework suggests that simultaneously addressing breastfeeding costs and benefits, in relation to how they are interpreted by mothers, will be most effective. Our approach focuses on contributors to the attitudes and commitment underlying breastfeeding outcomes, beginning in the prenatal period. We conclude that some maternal-offspring conflict is inherent with the dynamic infant feeding relationship. Guidance that anticipates and addresses family trade-offs over time can be incorporated into breastfeeding support for families. PMID:22188564

  13. Remedial Action Plan and site conceptual design for stabilization of the inactive uranium mill tailings site at Shiprock, New Mexico

    SciTech Connect

    Hill, T.V.; Morley, J.A. . Uranium Mill Tailings Remedial Action Project Office); Began, E.T. )

    1985-06-01

    This Remedial Action Plan (RAP) has been developed to serve a twofold purpose. It presents the series of activities which are proposed by the Department of Energy (DOE) to effect long-term control of radioactive materials at the inactive uranium processing site located on the Navajo Reservation at Shiprock, New Mexico. It also serves to document the concurrence of both the Navajo Nation and the Nuclear Regulatory Commission (NRC) in the remedial action. This document has been structured to provide a comprehensive understanding of the remedial action proposed for the Shiprock site. Detailed supporting information can be found in appendices and referenced documents. Section 2.0 presents the EPA standards, including a discussion of their objectives. Section 3.0 traces the history of operations at the Shiprock site with a description of the present site characteristics. Section 4.0 provides a definition of site-specific problems, a listing of remedial action alternatives which have been considered, and the action which is being proposed. Section 5.0 presents a summary of the conceptual design for the proposed action which includes objectives, design features, schedule, cost, and implementation methods. Section 6.0 summarizes the plan for ensuring health and safety protection for the surrounding community and the onsite workers. Section 7.0 presents a detailed listing of the responsibilities of the project participants. Section 8.0 describes the quality assurance process that will be used by the RAC during construction. Section 9.0 describes the features of the long-term maintenance and surveillance plan. Section 10.0 documents the on-going activities to keep the public informed and participating in the project. Attached as part of the RAP are five appendices which describe in more detail various aspects of the remedial action.

  14. The use of ecohydrological groundwater indicator plants in hydrogeological conceptual models

    NASA Astrophysics Data System (ADS)

    Lewis, J.

    2011-12-01

    Many plant species have been used for millennia as indicators of subsurface water. Under favorable circumstances, such ecohydrological indicators can suggest groundwater discharge areas, the depth to groundwater and the degree of mineralization. This information is available at virtually no expense and therefore has the potential to cost-effectively contribute to hydrogeological conceptual site models. However, very few hydrogeological studies take advantage of this inexpensive source of data. This review focuses on woody plants that are easily identified by earth scientists with little botanical training. Both facultative and obligate phreatophyte species are discussed. Riparian vegetation, being often found in groundwater discharge areas is covered in depth. The majority of published research concerning phreatophytes comes from the arid and semi-arid environments of the southwestern United States. However, this paper makes an effort to draw on data from several regions of the world and several fields of study. This includes a substantial body of research into geobotany from the former Soviet Union which has been largely overlooked by Western scholars. One of the most significant obstacles to using ecohydrological indicators in hydrogeological conceptual models is simply locating relevant information. Little has been published concerning indicator species in temperate, boreal and tropical zones. As a result, there is less useful information that can be deduced from groundwater indicator species in these climates. This article reviews both the state of the art and the potential for appliying ecohydrological groundwater indicator species to groundwater conceptual models. We conclude that ecohydrological groundwater indicators currently have the potential to cost effectively contribute to groundwater conceptual models in arid and semi-arid riparian zones. In climates that have an excess of moisture, extracting useful information from indicator species may require

  15. Evaluation of the US DOE's conceptual model of hydrothermal activity at Yucca Mountain, Nevada

    NASA Astrophysics Data System (ADS)

    Dublyansky, Y. V.

    2012-11-01

    A unique conceptual model envisaging conductive heating of rocks in the thick unsaturated zone of Yucca Mountain, Nevada by a silicic pluton emplaced several kilometers away is accepted by the US Department of Energy (DOE) as an explanation of the elevated depositional temperatures measured in fluid inclusions in secondary fluorite and calcite. Acceptance of this model allowed the DOE not to consider hydrothermal activity in the performance assessment of the proposed high-level nuclear waste disposal facility. Evaluation shows that validation of the model by computational modeling and by observations at a natural analog site was unsuccessful. Due to the lack of validation, the reliance on this model must be discontinued and the scientific defensibility of decisions which rely on this model must be re-evaluated.

  16. Secrets in Primary Care: A Qualitative Exploration and Conceptual Model

    PubMed Central

    Biderman, Aya; Mitki, Revital; Borkan, Jeffrey M.

    2007-01-01

    Objective Secrets and issues of confidentiality are critical concerns in doctor–patient communication and fundamental aspects of every medical encounter. Nevertheless, the nature, content, prevalence, impact, and consequences of secrets in medicine have largely been unexplored. This study investigates the role of secrets in primary care. It describes the intuitive strategies used by primary care physicians to cope with secrets, provides a categorization system, and suggests a conceptual model. Design Focus groups of primary care physicians were the principal data collection method employed. Transcripts from 8 focus groups were analyzed using an “immersion–crystallization” framework involving cycles of concentrated textual review of data. Insights from this iterative process and from the literature were employed in the construction of contextual types, content categories, processes, and models. Participants Sixty-one family physicians and general practitioners in Israel with a wide variety of seniority, ethnic, religious, and immigration backgrounds. Setting Locations in the north, south, and center of Israel. Results Analysis revealed insights about definitions, prevalence, process, and content of secrets in primary care. The main content findings centered on categories of secrets such as propensity to secrecy, toxicity of secrets, and the special nature of secrets in family medicine. The main process findings regarded the life cycle of secrets and doctors’ coping strategies. Based on our findings and a review of the literature, a conceptual model of secrets in primary care is proposed. Conclusions The importance and impact of secrets are significant part of daily medical practice. Further research is needed to enhance physicians’ effective and ethical handling of secrets and secrecy in practice. PMID:17487521

  17. Title I conceptual design for Pit 6 landfill closure at Lawrence Livermore National Laboratory Site 300

    SciTech Connect

    MacDonnell, B.A.; Obenauf, K.S.

    1996-08-01

    The objective of this design project is to evaluate and prepare design and construction documents for a closure cover cap for the Pit 6 Landfill located at Lawrence Livermore National Laboratory Site 300. This submittal constitutes the Title I Design (Conceptual Design) for the closure cover of the Pit 6 Landfill. A Title I Design is generally 30 percent of the design effort. Title H Design takes the design to 100 percent complete. Comments and edits to this Title I Design will be addressed in the Title II design submittal. Contents of this report are as follows: project background; design issues and engineering approach; design drawings; calculation packages; construction specifications outline; and construction quality assurance plan outline.

  18. Preclosure performance assessment review of the draft site characterization plan conceptual design report: Technical report

    SciTech Connect

    Waite, D.A.; Gupta, R.; Ludwig, S.B.; Maheras, S.J.; Mayberry, J.J.; Plummer, A.M.; Tarapore, P.S.

    1987-12-01

    This report presents the preclosure performance assessment review (PAR) of the Site Characterization Plan Conceptual Design Report (SCP-CDR). The PAR was performed on the design presented in the SCP-CDR working draft, Revision 1, released in October 1986. After review this working draft became the ''Site Characterization Plan Conceptual Design Report'', Revision 1. There are two distinct objectives of the PAR: (1) to analyze the design presented in the SCP-CDR in terms of offsite and occupational radiological safety, and (2) to test safety assessment methods and tools. This report addresses only the first of the PAR objectives. The PAR analysis consists of assessments of offsite and occupational doses resulting from routine and abnormal repository events. The scope of the analysis is restricted to preclosure operations at the repository. This report addresses (1) the description of repository facilities and operations, (2) the development of radioactive material inventories and radiation dose rates, (3) the development of radioactive material release scenarios and source terms, and (4) the assessment of offsite and occupational radiation dose equivalents. This report contains a summary of the analyses in the above four areas, and analysis details are documented. The results of the assessments are compared with regulatory requirements to determine how the repository performs relative to the requirements. The analyses indicate that the offsite and occupational impacts comply with regulatory requirements. However, based on this preliminary analysis of the draft design document, the occupational impacts exceed the SCP-CDR design objective of 1 rem/year in some areas. 59 refs., 12 figs., 127 tabs.

  19. Climate stability and sensitivity in some simple conceptual models

    NASA Astrophysics Data System (ADS)

    Bates, J. Ray

    2012-02-01

    A theoretical investigation of climate stability and sensitivity is carried out using three simple linearized models based on the top-of-the-atmosphere energy budget. The simplest is the zero-dimensional model (ZDM) commonly used as a conceptual basis for climate sensitivity and feedback studies. The others are two-zone models with tropics and extratropics of equal area; in the first of these (Model A), the dynamical heat transport (DHT) between the zones is implicit, in the second (Model B) it is explicitly parameterized. It is found that the stability and sensitivity properties of the ZDM and Model A are very similar, both depending only on the global-mean radiative response coefficient and the global-mean forcing. The corresponding properties of Model B are more complex, depending asymmetrically on the separate tropical and extratropical values of these quantities, as well as on the DHT coefficient. Adopting Model B as a benchmark, conditions are found under which the validity of the ZDM and Model A as climate sensitivity models holds. It is shown that parameter ranges of physical interest exist for which such validity may not hold. The 2 × CO2 sensitivities of the simple models are studied and compared. Possible implications of the results for sensitivities derived from GCMs and palaeoclimate data are suggested. Sensitivities for more general scenarios that include negative forcing in the tropics (due to aerosols, inadvertent or geoengineered) are also studied. Some unexpected outcomes are found in this case. These include the possibility of a negative global-mean temperature response to a positive global-mean forcing, and vice versa.

  20. Conceptual model and map of financial exploitation of older adults.

    PubMed

    Conrad, Kendon J; Iris, Madelyn; Ridings, John W; Fairman, Kimberly P; Rosen, Abby; Wilber, Kathleen H

    2011-10-01

    This article describes the processes and outcomes of three-dimensional concept mapping to conceptualize financial exploitation of older adults. Statements were generated from a literature review and by local and national panels consisting of 16 experts in the field of financial exploitation. These statements were sorted and rated using Concept Systems software, which grouped the statements into clusters and depicted them as a map. Statements were grouped into six clusters, and ranked by the experts as follows in descending severity: (a) theft and scams, (b) financial victimization, (c) financial entitlement, (d) coercion, (e) signs of possible financial exploitation, and (f) money management difficulties. The hierarchical model can be used to identify elder financial exploitation and differentiate it from related but distinct areas of victimization. The severity hierarchy may be used to develop measures that will enable more precise screening for triage of clients into appropriate interventions. PMID:21978290

  1. Rule based design of conceptual models for formative evaluation

    NASA Technical Reports Server (NTRS)

    Moore, Loretta A.; Chang, Kai; Hale, Joseph P.; Bester, Terri; Rix, Thomas; Wang, Yaowen

    1994-01-01

    A Human-Computer Interface (HCI) Prototyping Environment with embedded evaluation capability has been investigated. This environment will be valuable in developing and refining HCI standards and evaluating program/project interface development, especially Space Station Freedom on-board displays for payload operations. This environment, which allows for rapid prototyping and evaluation of graphical interfaces, includes the following four components: (1) a HCI development tool; (2) a low fidelity simulator development tool; (3) a dynamic, interactive interface between the HCI and the simulator; and (4) an embedded evaluator that evaluates the adequacy of a HCI based on a user's performance. The embedded evaluation tool collects data while the user is interacting with the system and evaluates the adequacy of an interface based on a user's performance. This paper describes the design of conceptual models for the embedded evaluation system using a rule-based approach.

  2. Rule based design of conceptual models for formative evaluation

    NASA Technical Reports Server (NTRS)

    Moore, Loretta A.; Chang, Kai; Hale, Joseph P.; Bester, Terri; Rix, Thomas; Wang, Yaowen

    1994-01-01

    A Human-Computer Interface (HCI) Prototyping Environment with embedded evaluation capability has been investigated. This environment will be valuable in developing and refining HCI standards and evaluating program/project interface development, especially Space Station Freedom on-board displays for payload operations. This environment, which allows for rapid prototyping and evaluation of graphical interfaces, includes the following four components: (1) a HCI development tool, (2) a low fidelity simulator development tool, (3) a dynamic, interactive interface between the HCI and the simulator, and (4) an embedded evaluator that evaluates the adequacy of a HCI based on a user's performance. The embedded evaluation tool collects data while the user is interacting with the system and evaluates the adequacy of an interface based on a user's performance. This paper describes the design of conceptual models for the embedded evaluation system using a rule-based approach.

  3. Alternative conceptual models and codes for unsaturated flow in fractured tuff: Preliminary assessments for GWTT-95

    SciTech Connect

    Ho, C.K.; Altman, S.J.; Arnold, B.W.

    1995-09-01

    Groundwater travel time (GWTT) calculations will play an important role in addressing site-suitability criteria for the potential high-level nuclear waste repository at Yucca Mountain,Nevada. In support of these calculations, Preliminary assessments of the candidate codes and models are presented in this report. A series of benchmark studies have been designed to address important aspects of modeling flow through fractured media representative of flow at Yucca Mountain. Three codes (DUAL, FEHMN, and TOUGH 2) are compared in these benchmark studies. DUAL is a single-phase, isothermal, two-dimensional flow simulator based on the dual mixed finite element method. FEHMN is a nonisothermal, multiphase, multidimensional simulator based primarily on the finite element method. TOUGH2 is anon isothermal, multiphase, multidimensional simulator based on the integral finite difference method. Alternative conceptual models of fracture flow consisting of the equivalent continuum model (ECM) and the dual permeability (DK) model are used in the different codes.

  4. Recurrence time distributions of large earthquakes in conceptual model studies

    NASA Astrophysics Data System (ADS)

    Zoeller, G.; Hainzl, S.

    2007-12-01

    The recurrence time distribution of large earthquakes in seismically active regions is a crucial ingredient for seismic hazard assessment. However, due to sparse observational data and a lack of knowledge on the precise mechanisms controlling seismicity, this distribution is unknown. In many practical applications of seismic hazard assessment, the Brownian passage time (BPT) distribution (or a different distribution) is fitted to a small number of observational recurrence times. Here, we study various aspects of recurrence time distributions in conceptual models of individual faults and fault networks: First, the dependence of the recurrence time distribution on the fault interaction is investigated by means of a network of Brownian relaxation oscillators. Second, the Brownian relaxation oscillator is modified towards a model for large earthquakes, taking into account also the statistics of intermediate events in a more appropriate way. This model simulates seismicity in a fault zone consisting of a major fault and some surrounding smaller faults with Gutenberg-Richter type seismicity. This model can be used for more realistic and robust estimations of the real recurrence time distribution in seismic hazard assessment.

  5. GIS-based Conceptual Database Model for Planetary Geoscientific Mapping

    NASA Astrophysics Data System (ADS)

    van Gasselt, Stephan; Nass, Andrea; Neukum, Gerhard

    2010-05-01

    We here report on the conceptual design of a geodatabase model as part of a larger-scaled GIS-based system composed of several applications, templates and database backend which supports conducting combined geological as well as geomorphological mapping of planetary surfaces and which simplifies the process of maintaining data and map products. Performing geological and/or geomorphological stand-alone or systematic mapping of planetary surfaces supported by modern GIS environments involves several tasks to be performed before the actual mapping process can be carried out. Such tasks deal with setting up a working environment by querying and defining raster data from a variety of planetary missions to be used and processed, importing auxiliary data, defining projection parameters for one or more map layer(s) and each raster/vector dataset, importing processed data, and defining a variety of vector shape geometries and attributes for mapping in terms of geometry type, representation symbology and attribute domains in a consistent way. In order to allow consistent mapping approaches and subsequent homogenisation success, a mapper makes use of pre-defined model schemas (templates) and definitions allowing to import mapping representation and styles as well as a backbone geo-database to immediately start working and making use of the provided infrastructure. The conceptual geo-database design developed far involves the design of the main object and data layers and consists of objects, object types, their relationships and additionally the formulation of integrity conditions on a level which is in principle independent of the exact implementation and its environment. Furthermore, the data layer containing attribute domains has been implemented. The conceptual design has been crafted using ESRI's ArcGIS File Geodatabase environment but it can be exported to any other GDBMS. The overall layout consists of several main elements or entity groups composed of relations

  6. Conceptual models of the evolution of transgressive dune field systems

    NASA Astrophysics Data System (ADS)

    Hesp, Patrick A.

    2013-10-01

    This paper examines the evolutionary paths of some transgressive dune fields that have formed on different coasts of the world, and presents some initial conceptual models of system dynamics for transgressive dune sheets and dune fields. Various evolutionary pathways are conceptualized based on a visual examination of dune fields from around the world. On coasts with high sediment supply, dune sheets and dune fields tend to accumulate as large scale barrier systems with little colonization of vegetation in arid-hyper to arid climate regimes, and as multiple, active discrete phases of dune field and deflation plain couplets in temperate to tropical environments. Active dune fields tend to be singular entities on coasts with low to moderate sediment supply. Landscape complexity and vegetation richness and diversity increases as dune fields evolve from simple active sheets and dunes to single and multiple deflation plains and basins, precipitation ridges, nebkha fields and a host of other dune types associated with vegetation (e.g. trailing ridges, slacks, remnant knobs, gegenwalle ridges and dune track ridges, 'tree islands' and 'bush pockets'). Three principal scenarios of transgressive dune sheet and dune field development are discussed, including dune sheets or dune fields evolving directly from the backshore, development following foredune and/or dune field erosion, and development from the breakdown or merging of parabolic dunes. Various stages of evolution are outlined for each scenario. Knowledge of evolutionary patterns and stages in coastal dune fields is very limited and caution is urged in attempts to reverse, change and/or modify dune fields to 'restore' some perceived loss of ecosystem or dune functioning.

  7. Conceptual models of the evolution of transgressive dune field systems

    NASA Astrophysics Data System (ADS)

    A. Hesp, Patrick

    2013-10-01

    This paper examines the evolutionary paths of some transgressive dune fields that have formed on different coasts of the world, and presents some initial conceptual models of system dynamics for transgressive dune sheets and dune fields. Various evolutionary pathways are conceptualized based on a visual examination of dune fields from around the world. On coasts with high sediment supply, dune sheets and dune fields tend to accumulate as large scale barrier systems with little colonization of vegetation in arid-hyper to arid climate regimes, and as multiple, active discrete phases of dune field and deflation plain couplets in temperate to tropical environments. Active dune fields tend to be singular entities on coasts with low to moderate sediment supply. Landscape complexity and vegetation richness and diversity increases as dune fields evolve from simple active sheets and dunes to single and multiple deflation plains and basins, precipitation ridges, nebkha fields and a host of other dune types associated with vegetation (e.g. trailing ridges, slacks, remnant knobs, gegenwalle ridges and dune track ridges, ‘tree islands' and ‘bush pockets'). Three principal scenarios of transgressive dune sheet and dune field development are discussed, including dune sheets or dune fields evolving directly from the backshore, development following foredune and/or dune field erosion, and development from the breakdown or merging of parabolic dunes. Various stages of evolution are outlined for each scenario. Knowledge of evolutionary patterns and stages in coastal dune fields is very limited and caution is urged in attempts to reverse, change and/or modify dune fields to ‘restore' some perceived loss of ecosystem or dune functioning.

  8. [Conceptual model of teasing and bullying in adolescents].

    PubMed

    Lien, Angela Shin-Yu; Dai, Yu-Tzu; Lee, Ya-Ling

    2013-08-01

    Teasing and bullying incident levels have increased markedly in recent years according to international news reports. School and community-level action to stop and prevent bullying is a key focus of government education policy worldwide. Teasing is a usual facet of social interaction among youth and is related to bullying behavior. Although teasing and bullying are significant concerns, references for relevant concept analysis are lacking in the nursing field. To facilitate early screening to identify high-risk bullies and help victims effectively stop bullying events, concept analysis is needed to clarify and distinguish between the two concepts of teasing and bullying. The aim of this study is to integrate relevant published literature to determine the reasons for and relationships between teasing and bullying. We chose obesity as an example to construct a teasing and bullying conceptual model for adolescents and used this model to explore the related factors and health impacts of obesity. We found that both teaser intent and recipient perceptions correlated with bullying behavior. Duration and severity may induce teasing to become bullying. Because weight-based teasing is common among adolescents, we chose obesity as an example issue to demonstrate our adolescents teasing and bullying concept model. We then integrated the antecedent and consequential factors of teasing and bullying for obese adolescents. Weight-control strategies can stop school bullying if early interventions are performed in high-risk populations. PMID:23922094

  9. A Hydrogeophysical Conceptual Model of Mount Toondina Impact Crater, South Australia

    NASA Astrophysics Data System (ADS)

    Dressler, D. K.; Halihan, T.; Love, A.; Xie, Y.; Simmons, C.

    2011-12-01

    Mount Toondina, located on the Great Artesian Basin (GAB), South Australia, is a meteorite impact crater and a ground water discharge feature with a water hole, a tufa salt flat and several former mapped springs. Aerial photographs and field survey data indicate that water was flowing from springs as recent as twenty years ago. Geophysical site surveys including electrical resistivity imaging (ERI), gravity and seismic data were utilized to constrain a hydrogeologic model for the site. Regional magnetic and gravity surveys were also utilized to evaluate the site boundaries using Oasis Montaj. Fluid chemistry and electrical conductivity from the site was used along with the geophysical data to constrain FEFLOW models to test hydrogeological conceptual models of the permeability structure of Mount Toondina. It is hypothesized that the spring system is controlled by advective flow from the subsurface artesian aquifer to the ring of vegetation around the perimeter of the impact structure. Additionally, it is hypothesized that the central salt flat portion of the impact crater is influenced by free convective processes. The field data and FEFLOW model results will be used to better manage flora and fauna in the Mount Toondina area and to better predict groundwater flow on other impact craters.

  10. Towards methodical modelling: Differences between the structure and output dynamics of multiple conceptual models

    NASA Astrophysics Data System (ADS)

    Knoben, Wouter; Woods, Ross; Freer, Jim

    2016-04-01

    Conceptual hydrologic models consist of a certain arrangement of spatial and temporal dynamics consisting of stores, fluxes and transformation functions, depending on the modeller's choices and intended use. They have the advantages of being computationally efficient, being relatively easy model structures to reconfigure and having relatively low input data demands. This makes them well-suited for large-scale and large-sample hydrology, where appropriately representing the dominant hydrologic functions of a catchment is a main concern. Given these requirements, the number of parameters in the model cannot be too high, to avoid equifinality and identifiability issues. This limits the number and level of complexity of dominant hydrologic processes the model can represent. Specific purposes and places thus require a specific model and this has led to an abundance of conceptual hydrologic models. No structured overview of these models exists and there is no clear method to select appropriate model structures for different catchments. This study is a first step towards creating an overview of the elements that make up conceptual models, which may later assist a modeller in finding an appropriate model structure for a given catchment. To this end, this study brings together over 30 past and present conceptual models. The reviewed model structures are simply different configurations of three basic model elements (stores, fluxes and transformation functions), depending on the hydrologic processes the models are intended to represent. Differences also exist in the inner workings of the stores, fluxes and transformations, i.e. the mathematical formulations that describe each model element's intended behaviour. We investigate the hypothesis that different model structures can produce similar behavioural simulations. This can clarify the overview of model elements by grouping elements which are similar, which can improve model structure selection.

  11. Student Conceptual Level and Models of Teaching: Theoretical and Empirical Coordination of Two Models.

    ERIC Educational Resources Information Center

    Hunt, David E.; And Others

    The Conceptual Level (CL) matching model describes the differential reaction of students varying in CL to educational environments varying in degree of structure. Models of teaching describe environments systematically varying in structure and therefore provide a specific basis for coordinated investigation of differential effects. The effects of…

  12. Computational Plume Modeling of COnceptual ARES Vehicle Stage Tests

    NASA Technical Reports Server (NTRS)

    Allgood, Daniel C.; Ahuja, Vineet

    2007-01-01

    The plume-induced environment of a conceptual ARES V vehicle stage test at the NASA Stennis Space Center (NASA-SSC) was modeled using computational fluid dynamics (CFD). A full-scale multi-element grid was generated for the NASA-SSC B-2 test stand with the ARES V stage being located in a proposed off-center forward position. The plume produced by the ARES V main power plant (cluster of five RS-68 LOX/LH2 engines) was simulated using a multi-element flow solver - CRUNCH. The primary objective of this work was to obtain a fundamental understanding of the ARES V plume and its impingement characteristics on the B-2 flame-deflector. The location, size and shape of the impingement region were quantified along with the un-cooled deflector wall pressures, temperatures and incident heating rates. Issues with the proposed tests were identified and several of these addressed using the CFD methodology. The final results of this modeling effort will provide useful data and boundary conditions in upcoming engineering studies that are directed towards determining the required facility modifications for ensuring safe and reliable stage testing in support of the Constellation Program.

  13. Description and evaluation of a mechanistically based conceptual model for spall

    SciTech Connect

    Hansen, F.D.; Knowles, M.K.; Thompson, T.W.

    1997-08-01

    A mechanistically based model for a possible spall event at the WIPP site is developed and evaluated in this report. Release of waste material to the surface during an inadvertent borehole intrusion is possible if future states of the repository include high gas pressure and waste material consisting of fine particulates having low mechanical strength. The conceptual model incorporates the physics of wellbore hydraulics coupled to transient gas flow to the intrusion borehole, and mechanical response of the waste. Degraded waste properties using of the model. The evaluations include both numerical and analytical implementations of the conceptual model. A tensile failure criterion is assumed appropriate for calculation of volumes of waste experiencing fragmentation. Calculations show that for repository gas pressures less than 12 MPa, no tensile failure occurs. Minimal volumes of material experience failure below gas pressure of 14 MPa. Repository conditions dictate that the probability of gas pressures exceeding 14 MPa is approximately 1%. For these conditions, a maximum failed volume of 0.25 m{sup 3} is calculated.

  14. The Marx Models as Conceptual Models in School Effectiveness Research.

    ERIC Educational Resources Information Center

    Giesbers, J. H. G. I.; Sleegers, P.

    1994-01-01

    Discusses the educational and organizational theory of Ernst Marx, the educational-organizational models he developed, and their use in Dutch secondary schools, particularly to enhance policymaking capacity. Marx theory embraces several basic ideas: the capacity to individualize instruction, to offer a broad education, to enhance operational…

  15. Addressing Conceptual Model Uncertainty in the Evaluation of Model Prediction Errors

    NASA Astrophysics Data System (ADS)

    Carrera, J.; Pool, M.

    2014-12-01

    Model predictions are uncertain because of errors in model parameters, future forcing terms, and model concepts. The latter remain the largest and most difficult to assess source of uncertainty in long term model predictions. We first review existing methods to evaluate conceptual model uncertainty. We argue that they are highly sensitive to the ingenuity of the modeler, in the sense that they rely on the modeler's ability to propose alternative model concepts. Worse, we find that the standard practice of stochastic methods leads to poor, potentially biased and often too optimistic, estimation of actual model errors. This is bad news because stochastic methods are purported to properly represent uncertainty. We contend that the problem does not lie on the stochastic approach itself, but on the way it is applied. Specifically, stochastic inversion methodologies, which demand quantitative information, tend to ignore geological understanding, which is conceptually rich. We illustrate some of these problems with the application to Mar del Plata aquifer, where extensive data are available for nearly a century. Geologically based models, where spatial variability is handled through zonation, yield calibration fits similar to geostatiscally based models, but much better predictions. In fact, the appearance of the stochastic T fields is similar to the geologically based models only in areas with high density of data. We take this finding to illustrate the ability of stochastic models to accommodate many data, but also, ironically, their inability to address conceptual model uncertainty. In fact, stochastic model realizations tend to be too close to the "most likely" one (i.e., they do not really realize the full conceptualuncertainty). The second part of the presentation is devoted to argue that acknowledging model uncertainty may lead to qualitatively different decisions than just working with "most likely" model predictions. Therefore, efforts should concentrate on

  16. The Value of Conceptual Models in Coping with Complexity and Interdisciplinarity in Environmental Sciences Education

    ERIC Educational Resources Information Center

    Fortuin, Karen P. J.; van Koppen, C. S. A.; Leemans, Rik

    2011-01-01

    Conceptual models are useful for facing the challenges of environmental sciences curriculum and course developers and students. These challenges are inherent to the interdisciplinary and problem-oriented character of environmental sciences curricula. In this article, we review the merits of conceptual models in facing these challenges. These…

  17. Semantic Description of Educational Adaptive Hypermedia Based on a Conceptual Model

    ERIC Educational Resources Information Center

    Papasalouros, Andreas; Retalis, Symeon; Papaspyrou, Nikolaos

    2004-01-01

    The role of conceptual modeling in Educational Adaptive Hypermedia Applications (EAHA) is especially important. A conceptual model of an educational application depicts the instructional solution that is implemented, containing information about concepts that must be ac-quired by learners, tasks in which learners must be involved and resources…

  18. A Conceptual Model of Pain Assessment for Noncommunicative Persons with Dementia

    ERIC Educational Resources Information Center

    Snow, A. Lynn; O'Malley, Kimberly J.; Cody, Marisue; Kunik, Mark E.; Ashton, Carol M.; Beck, Cornelia; Bruera, Eduardo; Novy, Diane

    2004-01-01

    Purpose: Our objectives are to present a conceptual model of the pain assessment process in persons with dementia and discuss methods for validating our model within this population. Design and Methods: This conceptual work is based on an integrative review and current pain theory, pain assessment research in demented and nondemented populations,…

  19. Teacher Emotion Research: Introducing a Conceptual Model to Guide Future Research

    ERIC Educational Resources Information Center

    Fried, Leanne; Mansfield, Caroline; Dobozy, Eva

    2015-01-01

    This article reports on the development of a conceptual model of teacher emotion through a review of teacher emotion research published between 2003 and 2013. By examining 82 publications regarding teacher emotion, the main aim of the review was to identify how teacher emotion was conceptualised in the literature and develop a conceptual model to…

  20. ABSTRACT: Design of Groundwater Monitoring Networks Considering Conceptual Model and Parametric Uncertainty

    SciTech Connect

    A. Hassan; H. Bekhit; Y. Zhang; J. Chapman

    2008-09-15

    Uncertainty built into conceptual groundwater flow and transport models and associated parametric uncertainty should be appropriately included when such models are used to develop detection monitoring networks for contaminated sites. We compare alternative approaches of propagating such uncertainty from the flow and transport model into the network design. The focus is on detection monitoring networks where the primary objective is to intercept the contaminant before it reaches a boundary of interest (e.g., compliance boundary). Different uncertainty propagation approaches identify different well locations and different well combinations (networks) as having the highest detection efficiency. It is thus recommended that multiple uncertainty propagation approaches are considered. If several approaches yield consistent results in terms of identifying the best performing candidate wells and the best performing well network for detecting a contaminant plume, this would provide confidence in the suitability of the selected well locations.

  1. Conceptual model for regional radionuclide transport from a salt dome repository: a technical memorandum

    SciTech Connect

    Kier, R.S.; Showalter, P.A.; Dettinger, M.D.

    1980-05-30

    Disposal of high-level radioactive wastes is a major environmental problem influencing further development of nuclear energy in this country. Salt domes in the Gulf Coast Basin are being investigated as repository sites. A major concern is geologic and hydrologic stability of candidate domes and potential transport of radionuclides by groundwater to the biosphere prior to their degradation to harmless levels of activity. This report conceptualizes a regional geohydrologic model for transport of radionuclides from a salt dome repository. The model considers transport pathways and the physical and chemical changes that would occur through time prior to the radionuclides reaching the biosphere. Necessary, but unknown inputs to the regional model involve entry and movement of fluids through the repository dome and across the dome-country rock interface and the effect on the dome and surrounding strata of heat generated by the radioactive wastes.

  2. Conceptual Models for the Fracture Network in Contaminated Shale Based on Different Lines of Evidence

    NASA Astrophysics Data System (ADS)

    Parker, B. L.; Chapman, S.; Cherry, J. A.

    2009-05-01

    In investigations of groundwater flow in fractured sedimentary rock, there is typically a large discrepancy between the number of fractures identified by different methods in boreholes. The methods directed at fracture geometry such as inspection of continuous core and borehole imaging (acoustic, optical, electrical televiewing, borehole camera, etc.) commonly identify numerous fractures. In contrast, the methods that infer fractures from measurements in the open borehole water column (borehole flow meters, temperature, electrical conductance, full borehole dilution) show far fewer fractures. These two different categories of data support two very different conceptual models for the fracture networks in which groundwater flow occurs. A study was conducted at a contaminated industrial site in an area of approximately 150m by 100m located on a fractured Ordovician shale in New York State where a fracture network conceptual model was initially developed based primarily on borehole flow metering and related cross-borehole hydraulic tests. In this conceptual model based on eight boreholes having a maximum depth of 50 m, the total number of flow zones identified was 14 over 140 m of open hole and ranged from none to five per hole. PCE DNAPL released decades ago has caused substantial VOC contamination (PCE, TCE, cis-DCE, and VC) and this contamination was delineated by means of a large number of contaminant analyses on samples from continuous rock core at an average spacing of 0.3 m. Although groundwater flow occurs almost entirely in the fractures, almost all the contaminant mass resides in the rock matrix (porosity 2-5%) because of long term diffusion-driven mass transfer from fractures to the matrix. The rock core contaminant profiles indicate that advective transport has occurred over decades through numerous fractures in each borehole. Therefore, many of the fractures identified from corelogs and televiewing must have active groundwater flow. This supports a

  3. Chlorine-36 data at Yucca Mountain: statistical tests of conceptual models for unsaturated-zone flow.

    PubMed

    Campbell, Katherine; Wolfsberg, Andrew; Fabryka-Martin, June; Sweetkind, Donald

    2003-01-01

    An extensive set of chlorine-36 (36Cl) data has been collected in the Exploratory Studies Facility (ESF), an 8-km-long tunnel at Yucca Mountain, Nevada, for the purpose of developing and testing conceptual models of flow and transport in the unsaturated zone (UZ) at this site. At several locations, the measured values of 36Cl/Cl ratios for salts leached from rock samples are high enough to provide strong evidence that at least a small component of bomb-pulse 36Cl, fallout from atmospheric testing of nuclear devices in the 1950s and 1960s, was measured, implying that some fraction of the water traveled from the ground surface through 200-300 m of unsaturated rock to the level of the ESF during the last 50 years. These data are analyzed here using a formal statistical approach based on log-linear models to evaluate alternative conceptual models for the distribution of such fast flow paths. The most significant determinant of the presence of bomb-pulse 36Cl in a sample from the welded Topopah Spring unit (TSw) is the structural setting from which the sample was collected. Our analysis generally supports the conceptual model that a fault that cuts through the nonwelded Paintbrush tuff unit (PTn) that overlies the TSw is required in order for bomb-pulse 36Cl to be transmitted to the sample depth in less than 50 years. Away from PTn-cutting faults, the ages of water samples at the ESF appear to be a strong function of the thickness of the nonwelded tuff between the ground surface and the ESF, due to slow matrix flow in that unit. PMID:12714284

  4. Chlorine-36 data at Yucca Mountain: Statistical tests of conceptual models for unsaturated-zone flow

    USGS Publications Warehouse

    Campbell, K.; Wolfsberg, A.; Fabryka-Martin, J.; Sweetkind, D.

    2003-01-01

    An extensive set of chlorine-36 (36Cl) data has been collected in the Exploratory Studies Facility (ESF), an 8-km-long tunnel at Yucca Mountain, Nevada, for the purpose of developing and testing conceptual models of flow and transport in the unsaturated zone (UZ) at this site. At several locations, the measured values of 36Cl/Cl ratios for salts leached from rock samples are high enough to provide strong evidence that at least a small component of bomb-pulse 36Cl, fallout from atmospheric testing of nuclear devices in the 1950s and 1960s, was measured, implying that some fraction of the water traveled from the ground surface through 200-300 m of unsaturated rock to the level of the ESF during the last 50 years. These data are analyzed here using a formal statistical approach based on log-linear models to evaluate alternative conceptual models for the distribution of such fast flow paths. The most significant determinant of the presence of bomb-pulse 36Cl in a sample from the welded Topopah Spring unit (TSw) is the structural setting from which the sample was collected. Our analysis generally supports the conceptual model that a fault that cuts through the nonwelded Paintbrush tuff unit (PTn) that overlies the TSw is required in order for bomb-pulse 36Cl to be transmitted to the sample depth in less than 50 years. Away from PTn-cutting faults, the ages of water samples at the ESF appear to be a strong function of the thickness of the nonwelded tuff between the ground surface and the ESF, due to slow matrix flow in that unit. ?? 2002 Elsevier Science B.V. All rights reserved.

  5. DSEM. Disposal Site Economic Model

    SciTech Connect

    Smith, P.R.

    1989-01-01

    The DISPOSAL SITE ECONOMIC MODEL calculates the average generator price, or average price per cubic foot charged by a disposal facility to a waste generator, one measure of comparing the economic attractiveness of different waste disposal site and disposal technology combinations. The generator price is calculated to recover all costs necessary to develop, construct, operate, close, and care for a site through the end of the institutional care period and to provide the necessary financial returns to the site developer and lender (when used). Six alternative disposal technologies, based on either private or public financing, can be considered - shallow land disposal, intermediate depth disposal, above or below ground vaults, modular concrete canister disposal, and earth mounded concrete bunkers - based on either private or public development.

  6. From conceptual model to remediation: bioavailability, a key to clean up heavy metal contaminated soils.

    NASA Astrophysics Data System (ADS)

    Petruzzelli, Gianniantonio; Pedron, Francesca; Pezzarossa, Beatrice

    2013-04-01

    Processes of metal bioavailability in the soil To know the bioavailability processes at site specific levels is essential to understand in detail the risks associated with pollution, and to support the decision-making process, i.e. description of the conceptual model and choice of clean up technologies. It is particularly important to assess how chemical, physical and biological processes in the soil affect the reactions leading to adsorption, precipitation or release of contaminants. The measurement of bioavailability One of the main difficulties in the practical application of the bioavailability concept in soil remediation is the lack of consensus on the method to be used to measure bioavailability. The best strategy is to apply a series of tests to assess bioavailability, since no applicable method is universally valid under all conditions. As an example, bioavailability tests for phytotechnology application should consider two distinct aspects: a physico-chemical driven solubilization process and a physiologically driven uptake process. Soil and plant characteristics strongly influence bioavailability. Bioavailability as a tool in remediation strategies Bioavailability can be used at all stages in remediation strategies: development of the conceptual model, evaluation of risk assessment, and selection of the best technology, considering different scenarios and including different environmental objectives. Two different strategies can be followed: the reduction and the increase of bioavailability. Procedures that reduce bioavailability aim to prevent the movement of pollutants from the soil to the living organisms, essentially by: i) removal of the labile phase of the contaminant, i.e. the fraction which is intrinsic to the processes of bioavailability (phytostabilization); ii) conversion of the labile fraction into a stable fraction (precipitation or adsorption); iii) increase of the resistance to mass transfer of the contaminants (inertization). Procedures

  7. Development of a conceptual model for vertical flow wetland metabolism.

    PubMed

    Giraldo, E; Zárate, E

    2001-01-01

    Four parallel vertical constructed wetlands, with a total area of 556 m2, are used to treat domestic wastewater, coming from a community of 550 inhabitants. The system includes pre-treatment with an anaerobic filter and post-treatment with chlorine, before discharging the effluent to the ocean. Four native species of macrophytes were planted: Paspalum penisetum, Typha sp, Conocarpres erectus and Scirpus lacustris. In situ measurements of gas content were performed for each bed during an operation cycle. After a feeding discharge, an unaltered sample of sand from each bed was taken, and a respirometric test was implemented to measure the metabolic activity in terms of oxygen consumption kinetics, CO2 production and organic matter degradation. The results were used to develop a conceptual model of the microbiologic metabolism for the process of organic matter removal from wastewater. Sorption in the bed is the main mechanism for organic matter removal from the wastewater, with subsequent biological oxidation during the resting period. The degradation rate for dissolved organic matter is found to be dependent on its concentration and on oxygen content in the gaseous phase. During the days of major activity, the oxygen content was not fully recovered when a new discharge occurred, finding anaerobic activity within the bed. PMID:11804107

  8. Burden of Illness in Hereditary Angioedema: A Conceptual Model.

    PubMed

    Bygum, Anette; Aygören-Pürsün, Emel; Beusterien, Kathleen; Hautamaki, Emily; Sisic, Zlatko; Wait, Suzanne; Boysen, Henrik B; Caballero, Teresa

    2015-07-01

    The objective of the Hereditary Angioedema Burden of Illness Study in Europe was to assess the real-world experience of hereditary angioedema (HAE) from the patient perspective. Based on open-ended qualitative interviews with 30 patients from Spain, Germany and Denmark, 5 key themes emerged characterizing the impact of HAE on health-related quality of life (HRQoL): (i) unnecessary treatments and procedures, (ii) symptom triggers, (iii) attack impacts, (iv) caregiver impacts, and (v) long-term impacts. Patients for example experience unnecessary medical procedures due to diagnostic delays; anxiety and fear about attacks, and passing HAE to children; reduced work/school productivity; and limited career/educational achievement. Patient caregivers also experience worry and work/activity interruption during the attacks. In conclusion, a conceptual model was developed illustrating the hypothesized relationships among the wide-ranging short- and long-term HRQoL impacts of HAE. These findings can be used to highlight important issues in clinical management, raise awareness of the patients' experience among policymakers and help guide measurement of HRQoL outcomes in future studies in HAE. PMID:25394853

  9. Initial Conceptualization and Application of the Alaska Thermokarst Model

    NASA Astrophysics Data System (ADS)

    Bolton, W. R.; Lara, M. J.; Genet, H.; Romanovsky, V. E.; McGuire, A. D.

    2015-12-01

    Thermokarst topography forms whenever ice-rich permafrost thaws and the ground subsides due to the volume loss when ground ice transitions to water. The Alaska Thermokarst Model (ATM) is a large-scale, state-and-transition model designed to simulate transitions between landscape units affected by thermokarst disturbance. The ATM uses a frame-based methodology to track transitions and proportion of cohorts within a 1-km2 grid cell. In the arctic tundra environment, the ATM tracks thermokarst-related transitions among wetland tundra, graminoid tundra, shrub tundra, and thermokarst lakes. In the boreal forest environment, the ATM tracks transitions among forested permafrost plateau, thermokarst lakes, collapse scar fens and bogs. The transition from one cohort to another due to thermokarst processes can take place if thaw reaches ice-rich ground layers either due to pulse disturbance (i.e. large precipitation event or fires), or due to gradual active layer deepening that eventually results in penetration of the protective layer. The protective layer buffers the ice-rich soils from the land surface and is critical to determine how susceptible an area is to thermokarst degradation. The rate of terrain transition in our model is determined by a set of rules that are based upon the ice-content of the soil, the drainage efficiency (or the ability of the landscape to store or transport water), the cumulative probability of thermokarst initiation, distance from rivers, lake dynamics (increasing, decreasing, or stable), and other factors. Tundra types are allowed to transition from one type to another (for example, wetland tundra to graminoid tundra) under favorable climatic conditions. In this study, we present our conceptualization and initial simulation results from in the arctic (the Barrow Peninsula) and boreal (the Tanana Flats) regions of Alaska.

  10. A Conceptual Model of the Formation of Filament Barbs

    NASA Astrophysics Data System (ADS)

    Martin, S. F.

    1997-05-01

    Barbs are the structures along the sides of a filament that connect its horizontal axis to chromosphere. The barbs, previously called 'legs' can be considered as magnetic field conduits along which mass is continuously guided and transported to and from the chromosphere. In the model presented, the barbs represent a secondary stage in filament formation which follows an intial stage in which a nearly horizontal axial magnetic field is first formed along a filament channel. Barb formation is most effectively and readily illustrated where the filament channel is broad and well-developed such as exists among the decaying network remnants of active regions. In these circumstances, the filament channel is a region of relatively low magnetic flux density compared to adjacent areas further from the polarity inversion. H-alpha filtergrams show that the axial parts of the filament are low and nearly contiguous with the chromosphere. The low height of the axial field, and the relative absence of concentrations of network magnetic field, are favorable conditions for magnetic reconnection between the axial field of the filament and new ephemeral regions and intranetwork magnetic fields beneath the filament. These reconnections lead to the formation of the barbs joining parts of the newly emerged fields to the axial field of the filament. Barb formation and motions seen in H-alpha filtergrams provide the evidence for this initial part of the conceptual model. The remaining part of the model is a demonstration of why only right-bearing barbs are seen on dextral filaments and left-bearing barbs on sinistral filaments; this is due to the sinistral or dextral magnetic configuration of the filament channel which does not permit the survival of barbs of the non-observed chirality as will be illustrated.