51 research outputs found

    Reducing Cognitive Load Using Hypervariate Display

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    This research examined the application of hypervariate display principles to human-computer interfaces with the intent of reducing the cognitive load placed on the operator during high-intensity activity. This research extended the existing body of knowledge relevant to reducing the cognitive load using human-computer interfaces. Existing research has explored the application of techniques that, when used in isolation, contribute to a computer operator\u27s understanding of the data or efficiency in execution of tasks. This research studied the collaborative use of proven display techniques to improve a computer operator\u27s ability to understand large amounts of data more rapidly and react to that data more effectively. These techniques, including the display of multiple variables in a single window, use of preattentive factors in the display, and the severing of geospatial dependencies on data significantly contributed to the reduction of cognitive burdens placed on a user in environments that are typically overwhelming. Experiments performed on 18 volunteer participants conclusively proved that the hypervariate display improved the participants\u27 ability to handle increased workload, comprehend complex situations quickly and completely, and efficiently respond to the situation in an effective manner. This research has significant value and broad application to user communities where computers are used to control high-intensity operations such as military and law enforcement environments

    Influence of curing on pore properties and strength of alkali activated mortars

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    The paper investigates the effect of wet/dry, wet and dry curing on the pore properties and strength of an alkali activated cementitious (AACM) mortar. The pore characteristics were determined from the cumulative and differential pore volume curves obtained by mercury intrusion porosimetry. AACM mortars possess a bimodal pore size distribution while the control PC mortar is unimodal. AACM mortars have a lower porosity, higher capillary pore volume, lower gel pore volume and lower critical and threshold pore diameters than the PC mortar which indicate greater durability potential of AACMs. Wet/dry curing is optimum for AACM mortars while wet curing is optimum for the PC mortar. Shrinkage and retarding admixtures improve the strength and pore structure of the AACMs

    Cementitious Barriers Partnership (CBP): Training and Release of CBP Toolbox Software, Version 1.0 -13480

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    ABSTRACT The Cementitious Barriers Partnership (CBP) Project is a multi-disciplinary, multi-institutional collaboration supported by the Office of Tank Waste Management within the Office of Environmental Management of U.S. Department of Energy (US DOE). The CBP program has developed a set of integrated tools (based on state-of-the-art models and leaching test methods) that improve understanding and predictions of the long-term hydraulic and chemical performance of cementitious barriers used in nuclear applications. Tools selected for and developed under this program are intended to evaluate and predict the behavior of cementitious barriers used in near-surface engineered waste disposal systems for periods of performance up to or longer than 100 years for operating facilities and longer than 1,000 years for waste management purposes. CBP software tools were made available to selected DOE Office of Environmental Management and field site users for training and evaluation based on a set of important degradation scenarios, including sulfate ingress/attack and carbonation of cementitious materials. The tools were presented at two-day training workshops held at U.S. National Institute of Standards and Technology (NIST), Savannah River, and Hanford included LeachXS™/ORCHESTRA, STADIUM®, and a CBP-developed GoldSim Dashboard interface. Collectively, these components form the CBP Software ToolBox. The new U.S. Environmental Protection Agency leaching test methods based on the Leaching Environmental Assessment Framework (LEAF) were also presented. The CBP Dashboard uses a custom Dynamic-link library developed by CBP to couple to the LeachXS™/ORCHESTRA and STADIUM® codes to simulate reactive transport and degradation in cementitious materials for selected performance assessment scenarios. The first day of the workshop introduced participants to the software components via presentation materials, and the second day included hands-on tutorial exercises followed by discussions of enhancements desired by participants. Tools were revised based on feedbac

    Investigating the utility of coupling COCOMO with a system dynamics simulation of software development

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    Cost estimation of software, in this era of budgetary constraints, is vitally important to the success or failure of a software project. Although there are many cost estimation models available, cost overruns and late deliveries still persist. Coupling the Constructive Cost model (COCOMO) and the Systems Dynamics Model of Software Project Management can provide a tool to study project management over the life of a project, to use sensitivity analysis to enhance COCOMO's cost driver set, and to utilize an automated optimization system for software cost estimation in a single or multi-project environment. This new type of model creates a means to study the multi-project environment and determine what the advantages and disadvantages are to sharing resources between different software projects. Several "C" programs were developed, that when interfaced and coupled with the system dynamic model, provide a tool to optimize cost estimates in a two project environment. It also creates an environment to perform extensive sensitivity analysis for the enhancement of COCOMO's cost driver set in the single and two project environment.http://archive.org/details/investigatinguti00smitLieutenant, United States NavyApproved for public release; distribution is unlimited

    REFERENCE CASES FOR USE IN THE CEMENTITOUS PARTNERSHIP PROJECT

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    The Cementitious Barriers Partnership Project (CBP) is a multi-disciplinary, multi-institution cross cutting collaborative effort supported by the US Department of Energy (DOE) to develop a reasonable and credible set of tools to improve understanding and prediction of the structural, hydraulic and chemical performance of cementitious barriers used in nuclear applications. The period of performance is >100 years for operating facilities and > 1000 years for waste management. The CBP has defined a set of reference cases to provide the following functions: (i) a common set of system configurations to illustrate the methods and tools developed by the CBP, (ii) a common basis for evaluating methodology for uncertainty characterization, (iii) a common set of cases to develop a complete set of parameter and changes in parameters as a function of time and changing conditions, (iv) a basis for experiments and model validation, and (v) a basis for improving conceptual models and reducing model uncertainties. These reference cases include the following two reference disposal units and a reference storage unit: (i) a cementitious low activity waste form in a reinforced concrete disposal vault, (ii) a concrete vault containing a steel high-level waste tank filled with grout (closed high-level waste tank), and (iii) a spent nuclear fuel basin during operation. Each case provides a different set of desired performance characteristics and interfaces between materials and with the environment. Examples of concretes, grout fills and a cementitious waste form are identified for the relevant reference case configurations
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