2,032 research outputs found
Conceptual Requirements for Command and Control Languages
Simulation Interoperability Standards Organization (SISO) SIW Conference PaperThe current Coalition Battle Management Language initiative (C-BML) will define a language to
unambiguously exchange command and control information between systems. This paper introduces a categorization
that may be used to guide the process of developing C-BML effectively by enumerating the conceptual requirements the
authors have identified in model-based data engineering and process engineering based studies in various domains
Conceptual Requirements for Command and Control Languages
The current Coalition Battle Management Language initiative (C-BML) will define a language to unambiguously exchange command and control information between systems. This paper introduces a categorization that may be used to guide the process of developing C-BML effectively by enumerating the conceptual requirements the authors have identified in model-based data engineering and process engineering based studies in various domains.
First, it is important to distinguish if application of the language will support the planning, execution, or observation phase of command and control. While C-BML already distinguishes between tasking and reporting, planning is a category with different requirements.
Second, the language must be able to express various spatio-temporal constraints, which can be expressed using fixed expressions, relative to each other, or in mixed forms. In addition to the traditional spatio-temporal constraints, operation-specific constraints – or the perception thereof – need to be expressed.
Finally, it must be determined if the constraints are used in support of accomplishment-driven objectives or avoidance-driven objectives. While this category seems to be trivial to most human consumers of the language, it has significant implications for systems.
The paper introduces the conceptual constraints using examples and evaluates mathematical means provided by discrete structures needed for computation to describe their ability to cope with these challenges
Modelling representation errors of atmospheric CO2 mixing ratios at a regional scale
Inverse modelling of carbon sources and sinks requires an accurate quality estimate of the modelling framework to obtain a realistic estimate of the inferred fluxes and their uncertainties. So-called "representation errors" result from our inability to correctly represent point observations with simulated average values of model grid cells. They may add substantial uncertainty to the interpretation of atmospheric CO2 mixing ratio data. We simulated detailed variations in the CO2 mixing ratios with a high resolution (2 km) mesoscale model (RAMS) to estimate the representation errors introduced at larger model grid sizes of 10 100 km. We found that meteorology is the main driver of representation errors in our study causing spatial and temporal variations in the error estimate. Within the nocturnal boundary layer, the representation errors are relatively large and mainly caused by unresolved topography at lower model resolutions. During the day, convective structures, mesoscale circulations, and surface CO2 flux variability were found to be the main sources of representation errors. Interpreting observations near a mesoscale circulation as representative for air with the correct footprint relative to the front can reduce the representation error substantially. The remaining representation error is 0.5 1.5 ppm at 20 100 km resolution
Reconfiguration and dissociation of bonded hydrogen in silicon by energetic ions
We report in situ infrared measurements of ion-induced reconfiguration and dissociation of bonded hydrogen associated with various defects in silicon at low temperatures. Defect-associated Si-H complexes were prepared by low-temperature proton implantation in silicon followed by room-temperature annealing. As a result of subsequent low-temperature (3)He ion irradiation, we observed (1) ion-induced dissociation of Si-H complexes, (2) a notable difference in the dissociation rate of interstitial- and vacancy-type defects, and, unexpectedly, (3) the growth of bond-centered hydrogen, which is generally observed in association with low-temperature proton implantation. These findings provide insight into the mechanisms responsible for the dissociation of hydrogen bonds in silicon and thus have important implications for bond-selective nanoscale engineering and the long-term reliability of state-of-the-art silicon semiconductor and photovoltaic devices
Testing of a Water Loss Distribution Model for Moving Sprinkler Systems
Field water balance measurements using monolithic lysimeters were used in validating the Cupid-DPE model for predicting water loss partitioning during sprinkler irrigation from a moving lateral system fitted with impact sprinklers and spray nozzles. The model combines equations governing water droplet evaporation and droplet ballistics with a comprehensive plant-environment energy balance model. Comparisons indicate good agreement between measured and modeled transpiration, and the measured and modeled soil evaporation during the day of irrigation. Total predicted evapotranspiration during the day of irrigation was greater than measured totals using the monolithic lysimeters. However, part of this difference was because the lysimeters could not measure water use during irrigation. Total measured and predicted evapo-transpiration agreed well for the day following irrigation. Predicted soil evaporation rates matched well for the period immediately following irrigation, and cumulative soil evaporation was nearly identical to the measured total through the end of the next day. During irrigation, the main water loss was shifted from transpiration to evaporation of the wetted-canopy. For equal application volumes, the duration of this effect was greater using impact sprinklers due to the greater wetted diameter and lower average application rate compared to spray nozzles. Predicted water flux rates during irrigation were up to 50% greater for canopy evaporation than for transpiration rates predicted immediately prior to the start of irrigation. Canopy evaporation amounted to 69% and 63% of the total predicted water use during impact and spray irrigation, respectively. It also was 0.69 and 0.28 mm greater, respectively, than the predicted transpiration total during this same time span assuming no irrigation had been applied. About 13 and 5% of the water applied by overhead sprinkling was evaporated or transpired during impact and spray irrigation, respectively. However, the net increase in predicted water loss during irrigation was only 5.8% and 2.4% of the irrigated water depth applied for the impact and spray cases, respectively, because transpiration and soil evaporation would have occurred even without irrigation. Although droplet evaporation represented less than 1% of the total water loss for the day using either type of sprinkler, irrigation water did influence the energy transfer between the plant-environment and water droplets during flight, on the canopy, and the soil
ET mapping for agricultural water management: present status and challenges
Evapotranspiration (ET) is an essential component of the water balance. Remote sensing based agrometeorological models are presently most suited for estimating crop water use at both field and regional scales. Numerous ET algorithms have been developed to make use of remote sensing data acquired by sensors on airborne and satellite platforms. In this paper, a literature review was done to evaluate numerous commonly used remote sensing based algorithms for their ability to estimate regional ET accurately. The reported estimation accuracy varied from 67 to 97% for daily ET and above 94% for seasonal ET indicating that they have the potential to estimate regional ET accurately. However, there are opportunities to further improving these models for accurately estimating all energy balance components. The spatial and temporal remote sensing data from the existing set of earth observing satellite platforms are not sufficient enough to be used in the estimation of spatially distributed ET for on-farm irrigation management purposes, especially at a field scale level (~10 to 200 ha). This will be constrained further if the thermal sensors on future Landsat satellites are abandoned. However, research opportunities exist to improve the spatial and temporal resolution of ET by developing algorithms to increase the spatial resolution of reflectance and surface temperature data derived from Landsat/ ASTER/MODIS images using same/other-sensor high resolution multi-spectral images
MATHEMATICAL MODELS TOWARDS SELF-ORGANIZING FORMAL FEDERATION LANGUAGES BASED ON CONCEPTUAL MODELS OF INFORMATION EXCHANGE CAPABILITIES
Conceptual models capture information that is crucial for composability of legacy solutions that is not formally captured in the derived technical artifacts. It is necessary to make this information available for the selection (or elimination) of available solutions, their orchestration, and their execution. Current standards barely address this class of problems. The approach presented in this paper is the first step towards self-organizing federation languages. The system interfaces are described in form of exchangeable data. The context of information exchange (syntax, semantics, and pragmatics) is captured as metadata. These metadata are used to identify the elements of a formal federation language that links model composability and simulation interoperability based on conceptual model elements. The paper describes the formal process of selection, orchestration, and execution and the underlying mathematics for the information exchange specifications that bridge conceptual and engineering levels of the federation process.
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