A large-eddy simulation based power estimation capability for wind farms over complex terrain

Science.gov (United States)

Senocak, I.; Sandusky, M.; Deleon, R.

2017-12-01

There has been an increasing interest in predicting wind fields over complex terrain at the micro-scale for resource assessment, turbine siting, and power forecasting. These capabilities are made possible by advancements in computational speed from a new generation of computing hardware, numerical methods and physics modelling. The micro-scale wind prediction model presented in this work is based on the large-eddy simulation paradigm with surface-stress parameterization. The complex terrain is represented using an immersed-boundary method that takes into account the parameterization of the surface stresses. Governing equations of incompressible fluid flow are solved using a projection method with second-order accurate schemes in space and time. We use actuator disk models with rotation to simulate the influence of turbines on the wind field. Data regarding power production from individual turbines are mostly restricted because of proprietary nature of the wind energy business. Most studies report percentage drop of power relative to power from the first row. There have been different approaches to predict power production. Some studies simply report available wind power in the upstream, some studies estimate power production using power curves available from turbine manufacturers, and some studies estimate power as torque multiplied by rotational speed. In the present work, we propose a black-box approach that considers a control volume around a turbine and estimate the power extracted from the turbine based on the conservation of energy principle. We applied our wind power prediction capability to wind farms over flat terrain such as the wind farm over Mower County, Minnesota and the Horns Rev offshore wind farm in Denmark. The results from these simulations are in good agreement with published data. We also estimate power production from a hypothetical wind farm in complex terrain region and identify potential zones suitable for wind power production.

Simulation of tracer dispersion from elevated and surface releases in complex terrain

Science.gov (United States)

Hernández, J. F.; Cremades, L.; Baldasano, J. M.

A new version of an advanced mesoscale dispersion modeling system for simulating passive air pollutant dispersion in the real atmospheric planetary boundary layer (PBL), is presented. The system comprises a diagnostic mass-consistent meteorological model and a Lagrangian particle dispersion model (LADISMO). The former version of LADISMO, developed according to Zannetti (Air pollution modelling, 1990), was based on the Monte Carlo technique and included calculation of higher-order moments of vertical random forcing for convective conditions. Its ability to simulate complex flow dispersion has been stated in a previous paper (Hernández et al. 1995, Atmospheric Environment, 29A, 1331-1341). The new version follows Thomson's scheme (1984, Q. Jl Roy. Met. Soc.110, 1107-1120). It is also based on Langevin equation and follows the ideas given by Brusasca et al. (1992, Atmospheric Environment26A, 707-723) and Anfossi et al. (1992, Nuovo Cemento 15c, 139-158). The model is used to simulate the dispersion and predict the ground level concentration (g.l.c.) of a tracer (SF 6) released from both an elevated source ( case a) and a ground level source ( case b) in a highly complex mountainous terrain during neutral and synoptically dominated conditions ( case a) and light and apparently stable conditions ( case b). The last case is considered as being a specially difficult task to simulate. In fact, few works have reported situations with valley drainage flows in complex terrains and real stable atmospheric conditions with weak winds. The model assumes that nearly calm situations associated to strong stability and air stagnation, make the lowest layers of PBL poorly diffusive (Brusasca et al., 1992, Atmospheric Environment26A, 707-723). Model results are verified against experimental data from Guardo-90 tracer experiments, an intensive field campaign conducted in the Carrion river valley (Northern Spain) to study atmospheric diffusion within a steep walled valley in mountainous

Numerical Simulation of a Lee Wave Case over Three-Dimensional Mountainous Terrain under Strong Wind Condition

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Lei Li

2013-01-01

Full Text Available This study of a lee wave event over three-dimensional (3D mountainous terrain in Lantau Island, Hong Kong, using a simulation combining mesoscale model and computational fluid dynamics (CFD model has shown that (1 3D steep mountainous terrain can trigger small scale lee waves under strong wind condition, and the horizontal extent of the wave structure is in a dimension of few kilometers and corresponds to the dimension of the horizontal cross-section of the mountain; (2 the life cycle of the lee wave is short, and the wave structures will continuously form roughly in the same location, then gradually move downstream, and dissipate over time; (3 the lee wave triggered by the mountainous terrain in this case can be categorized into “nonsymmetric vortex shedding” or “turbulent wake,” as defined before based on water tank experiments; (4 the magnitude of the wave is related to strength of wind shear. This study also shows that a simulation combining mesoscale model and CFD can capture complex wave structure in the boundary layer over realistic 3D steep terrain, and have a potential value for operational jobs on air traffic warning, wind energy utilization, and atmospheric environmental assessment.

New high-fidelity terrain modeling method constrained by terrain semanteme.

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Bo Zhou

Full Text Available Production of higher-fidelity digital elevation models is important; as such models are indispensable components of space data infrastructure. However, loss of terrain features is a constant problem for grid digital elevation models, although these models have already been defined in such a way that their distinct usage as data sources in terrain modeling processing is prohibited. Therefore, in this study, the novel concept-terrain semanteme is proposed to define local space terrain features, and a new process for generating grid digital elevation models based on this new concept is designed. A prototype system is programmed to test the proposed approach; the results indicate that terrain semanteme can be applied in the process of grid digital elevation model generation, and that usage of this new concept improves the digital elevation model fidelity. Moreover, the terrain semanteme technique can be applied for recovery of distorted digital elevation model regions containing terrain semantemes, with good recovery efficiency indicated by experiments.

Simulation and Analysis of the Topographic Effects on Snow-Free Albedo over Rugged Terrain

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Dalei Hao

2018-02-01

Full Text Available Topography complicates the modeling and retrieval of land surface albedo due to shadow effects and the redistribution of incident radiation. Neglecting topographic effects may lead to a significant bias when estimating land surface albedo over a single slope. However, for rugged terrain, a comprehensive and systematic investigation of topographic effects on land surface albedo is currently ongoing. Accurately estimating topographic effects on land surface albedo over a rugged terrain presents a challenge in remote sensing modeling and applications. In this paper, we focused on the development of a simplified estimation method for snow-free albedo over a rugged terrain at a 1-km scale based on a 30-m fine-scale digital elevation model (DEM. The proposed method was compared with the radiosity approach based on simulated and real DEMs. The results of the comparison showed that the proposed method provided adequate computational efficiency and satisfactory accuracy simultaneously. Then, the topographic effects on snow-free albedo were quantitatively investigated and interpreted by considering the mean slope, subpixel aspect distribution, solar zenith angle, and solar azimuth angle. The results showed that the more rugged the terrain and the larger the solar illumination angle, the more intense the topographic effects were on black-sky albedo (BSA. The maximum absolute deviation (MAD and the maximum relative deviation (MRD of the BSA over a rugged terrain reached 0.28 and 85%, respectively, when the SZA was 60° for different terrains. Topographic effects varied with the mean slope, subpixel aspect distribution, SZA and SAA, which should not be neglected when modeling albedo.

Tests of high-resolution simulations over a region of complex terrain in Southeast coast of Brazil

Science.gov (United States)

Chou, Sin Chan; Luís Gomes, Jorge; Ristic, Ivan; Mesinger, Fedor; Sueiro, Gustavo; Andrade, Diego; Lima-e-Silva, Pedro Paulo

2013-04-01

The Eta Model is used operationally by INPE at the Centre for Weather Forecasts and Climate Studies (CPTEC) to produce weather forecasts over South America since 1997. The model has gone through upgrades along these years. In order to prepare the model for operational higher resolution forecasts, the model is configured and tested over a region of complex topography located near the coast of Southeast Brazil. The model domain includes the two Brazilians cities, Rio de Janeiro and Sao Paulo, urban areas, preserved tropical forest, pasture fields, and complex terrain where it can rise from sea level up to about 1000 m. Accurate near-surface wind direction and magnitude are needed for the power plant emergency plan. Besides, the region suffers from frequent events of floods and landslides, therefore accurate local forecasts are required for disaster warnings. The objective of this work is to carry out a series of numerical experiments to test and evaluate high resolution simulations in this complex area. Verification of model runs uses observations taken from the nuclear power plant and higher resolution reanalyses data. The runs were tested in a period when flow was predominately forced by local conditions and in a period forced by frontal passage. The Eta Model was configured initially with 2-km horizontal resolution and 50 layers. The Eta-2km is a second nesting, it is driven by Eta-15km, which in its turn is driven by Era-Interim reanalyses. The series of experiments consists of replacing surface layer stability function, adjusting cloud microphysics scheme parameters, further increasing vertical and horizontal resolutions. By replacing the stability function for the stable conditions substantially increased the katabatic winds and verified better against the tower wind data. Precipitation produced by the model was excessive in the region. Increasing vertical resolution to 60 layers caused a further increase in precipitation production. This excessive

ATON (Autonomous Terrain-based Optical Navigation) for exploration missions: recent flight test results

Science.gov (United States)

Theil, S.; Ammann, N.; Andert, F.; Franz, T.; Krüger, H.; Lehner, H.; Lingenauber, M.; Lüdtke, D.; Maass, B.; Paproth, C.; Wohlfeil, J.

2018-03-01

Since 2010 the German Aerospace Center is working on the project Autonomous Terrain-based Optical Navigation (ATON). Its objective is the development of technologies which allow autonomous navigation of spacecraft in orbit around and during landing on celestial bodies like the Moon, planets, asteroids and comets. The project developed different image processing techniques and optical navigation methods as well as sensor data fusion. The setup—which is applicable to many exploration missions—consists of an inertial measurement unit, a laser altimeter, a star tracker and one or multiple navigation cameras. In the past years, several milestones have been achieved. It started with the setup of a simulation environment including the detailed simulation of camera images. This was continued by hardware-in-the-loop tests in the Testbed for Robotic Optical Navigation (TRON) where images were generated by real cameras in a simulated downscaled lunar landing scene. Data were recorded in helicopter flight tests and post-processed in real-time to increase maturity of the algorithms and to optimize the software. Recently, two more milestones have been achieved. In late 2016, the whole navigation system setup was flying on an unmanned helicopter while processing all sensor information onboard in real time. For the latest milestone the navigation system was tested in closed-loop on the unmanned helicopter. For that purpose the ATON navigation system provided the navigation state for the guidance and control of the unmanned helicopter replacing the GPS-based standard navigation system. The paper will give an introduction to the ATON project and its concept. The methods and algorithms of ATON are briefly described. The flight test results of the latest two milestones are presented and discussed.

The Efficacy of Using Synthetic Vision Terrain-Textured Images to Improve Pilot Situation Awareness

Science.gov (United States)

Uenking, Michael D.; Hughes, Monica F.

2002-01-01

The General Aviation Element of the Aviation Safety Program's Synthetic Vision Systems (SVS) Project is developing technology to eliminate low visibility induced General Aviation (GA) accidents. SVS displays present computer generated 3-dimensional imagery of the surrounding terrain on the Primary Flight Display (PFD) to greatly enhance pilot's situation awareness (SA), reducing or eliminating Controlled Flight into Terrain, as well as Low-Visibility Loss of Control accidents. SVS-conducted research is facilitating development of display concepts that provide the pilot with an unobstructed view of the outside terrain, regardless of weather conditions and time of day. A critical component of SVS displays is the appropriate presentation of terrain to the pilot. An experimental study is being conducted at NASA Langley Research Center (LaRC) to explore and quantify the relationship between the realism of the terrain presentation and resulting enhancements of pilot SA and performance. Composed of complementary simulation and flight test efforts, Terrain Portrayal for Head-Down Displays (TP-HDD) experiments will help researchers evaluate critical terrain portrayal concepts. The experimental effort is to provide data to enable design trades that optimize SVS applications, as well as develop requirements and recommendations to facilitate the certification process. In this part of the experiment a fixed based flight simulator was equipped with various types of Head Down flight displays, ranging from conventional round dials (typical of most GA aircraft) to glass cockpit style PFD's. The variations of the PFD included an assortment of texturing and Digital Elevation Model (DEM) resolution combinations. A test matrix of 10 terrain display configurations (in addition to the baseline displays) were evaluated by 27 pilots of various backgrounds and experience levels. Qualitative (questionnaires) and quantitative (pilot performance and physiological) data were collected during

Using the power balance model to simulate cross-country skiing on varying terrain

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Moxnes JF

2014-05-01

Full Text Available John F Moxnes,1 Øyvind Sandbakk,2 Kjell Hausken31Department for Protection, Norwegian Defence Research Establishment, Kjeller, Norway; 2Center for Elite Sports Research, Department of Neuroscience, Norwegian University of Science and Technology, Trondheim, Norway; 3Faculty of Social Sciences, University of Stavanger, Stavanger, NorwayAbstract: The current study adapts the power balance model to simulate cross-country skiing on varying terrain. We assumed that the skier’s locomotive power at a self-chosen pace is a function of speed, which is impacted by friction, incline, air drag, and mass. An elite male skier’s position along the track during ski skating was simulated and compared with his experimental data. As input values in the model, air drag and friction were estimated from the literature based on the skier's mass, snow conditions, and speed. We regard the fit as good, since the difference in racing time between simulations and measurements was 2 seconds of the 815 seconds racing time, with acceptable fit both in uphill and downhill terrain. Using this model, we estimated the influence of changes in various factors such as air drag, friction, and body mass on performance. In conclusion, the power balance model with locomotive power as a function of speed was found to be a valid tool for analyzing performance in cross-country skiing.Keywords: air drag, efficiency, friction coefficient, speed, locomotive power

Selection method of terrain matching area for TERCOM algorithm

Science.gov (United States)

Zhang, Qieqie; Zhao, Long

2017-10-01

The performance of terrain aided navigation is closely related to the selection of terrain matching area. The different matching algorithms have different adaptability to terrain. This paper mainly studies the adaptability to terrain of TERCOM algorithm, analyze the relation between terrain feature and terrain characteristic parameters by qualitative and quantitative methods, and then research the relation between matching probability and terrain characteristic parameters by the Monte Carlo method. After that, we propose a selection method of terrain matching area for TERCOM algorithm, and verify the method correctness with real terrain data by simulation experiment. Experimental results show that the matching area obtained by the method in this paper has the good navigation performance and the matching probability of TERCOM algorithm is great than 90%

Hybrid RANS/LES applied to complex terrain

DEFF Research Database (Denmark)

Bechmann, Andreas; Sørensen, Niels N.

2011-01-01

Large Eddy Simulation (LES) of the wind in complex terrain is limited by computational cost. The number of computational grid points required to resolve the near-ground turbulent structures (eddies) are very high. The traditional solution to the problem has been to apply a wall function...... aspect ratio in the RANS layer and thereby resolve the mean near-wall velocity profile. The method is applicable to complex terrain and the benefits of traditional LES are kept intact. Using the hybrid method, simulations of the wind over a natural complex terrain near Wellington in New Zealand...... that accounts for the whole near-wall region. Recently, a hybrid method was proposed in which the eddies close to the ground were modelled in a Reynolds-averaged sense (RANS) and the eddies above this region were simulated using LES. The advantage of the approach is the ability to use shallow cells of high...

Simulations of Turbulent Flow Over Complex Terrain Using an Immersed-Boundary Method

Science.gov (United States)

DeLeon, Rey; Sandusky, Micah; Senocak, Inanc

2018-02-01

We present an immersed-boundary method to simulate high-Reynolds-number turbulent flow over the complex terrain of Askervein and Bolund Hills under neutrally-stratified conditions. We reconstruct both the velocity and the eddy-viscosity fields in the terrain-normal direction to produce turbulent stresses as would be expected from the application of a surface-parametrization scheme based on Monin-Obukhov similarity theory. We find that it is essential to be consistent in the underlying assumptions for the velocity reconstruction and the eddy-viscosity relation to produce good results. To this end, we reconstruct the tangential component of the velocity field using a logarithmic velocity profile and adopt the mixing-length model in the near-surface turbulence model. We use a linear interpolation to reconstruct the normal component of the velocity to enforce the impermeability condition. Our approach works well for both the Askervein and Bolund Hills when the flow is attached to the surface, but shows slight disagreement in regions of flow recirculation, despite capturing the flow reversal.

Simulations of Turbulent Flow Over Complex Terrain Using an Immersed-Boundary Method

Science.gov (United States)

DeLeon, Rey; Sandusky, Micah; Senocak, Inanc

2018-06-01

We present an immersed-boundary method to simulate high-Reynolds-number turbulent flow over the complex terrain of Askervein and Bolund Hills under neutrally-stratified conditions. We reconstruct both the velocity and the eddy-viscosity fields in the terrain-normal direction to produce turbulent stresses as would be expected from the application of a surface-parametrization scheme based on Monin-Obukhov similarity theory. We find that it is essential to be consistent in the underlying assumptions for the velocity reconstruction and the eddy-viscosity relation to produce good results. To this end, we reconstruct the tangential component of the velocity field using a logarithmic velocity profile and adopt the mixing-length model in the near-surface turbulence model. We use a linear interpolation to reconstruct the normal component of the velocity to enforce the impermeability condition. Our approach works well for both the Askervein and Bolund Hills when the flow is attached to the surface, but shows slight disagreement in regions of flow recirculation, despite capturing the flow reversal.

Fractal Landscape Algorithms for Environmental Simulations

Science.gov (United States)

Mao, H.; Moran, S.

2014-12-01

Natural science and geographical research are now able to take advantage of environmental simulations that more accurately test experimental hypotheses, resulting in deeper understanding. Experiments affected by the natural environment can benefit from 3D landscape simulations capable of simulating a variety of terrains and environmental phenomena. Such simulations can employ random terrain generation algorithms that dynamically simulate environments to test specific models against a variety of factors. Through the use of noise functions such as Perlin noise, Simplex noise, and diamond square algorithms, computers can generate simulations that model a variety of landscapes and ecosystems. This study shows how these algorithms work together to create realistic landscapes. By seeding values into the diamond square algorithm, one can control the shape of landscape. Perlin noise and Simplex noise are also used to simulate moisture and temperature. The smooth gradient created by coherent noise allows more realistic landscapes to be simulated. Terrain generation algorithms can be used in environmental studies and physics simulations. Potential studies that would benefit from simulations include the geophysical impact of flash floods or drought on a particular region and regional impacts on low lying area due to global warming and rising sea levels. Furthermore, terrain generation algorithms also serve as aesthetic tools to display landscapes (Google Earth), and simulate planetary landscapes. Hence, it can be used as a tool to assist science education. Algorithms used to generate these natural phenomena provide scientists a different approach in analyzing our world. The random algorithms used in terrain generation not only contribute to the generating the terrains themselves, but are also capable of simulating weather patterns.

A method for simulating the release of natural gas from the rupture of high-pressure pipelines in any terrain.

Science.gov (United States)

Deng, Yajun; Hu, Hongbing; Yu, Bo; Sun, Dongliang; Hou, Lei; Liang, Yongtu

2018-01-15

The rupture of a high-pressure natural gas pipeline can pose a serious threat to human life and environment. In this research, a method has been proposed to simulate the release of natural gas from the rupture of high-pressure pipelines in any terrain. The process of gas releases from the rupture of a high-pressure pipeline is divided into three stages, namely the discharge, jet, and dispersion stages. Firstly, a discharge model is established to calculate the release rate of the orifice. Secondly, an improved jet model is proposed to obtain the parameters of the pseudo source. Thirdly, a fast-modeling method applicable to any terrain is introduced. Finally, based upon these three steps, a dispersion model, which can take any terrain into account, is established. Then, the dispersion scenarios of released gas in four different terrains are studied. Moreover, the effects of pipeline pressure, pipeline diameter, wind speed and concentration of hydrogen sulfide on the dispersion scenario in real terrain are systematically analyzed. The results provide significant guidance for risk assessment and contingency planning of a ruptured natural gas pipeline. Copyright © 2017. Published by Elsevier B.V.

Numerical simulations of windblown dust over complex terrain: the Fiambalá Basin episode in June 2015

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L. A. Mingari

2017-06-01

MSG-SEVIRI retrieval product. We tested two numerical schemes: with the default configuration of the FALL3D model, we found difficulties to simulate transport through orographic barriers, whereas an alternative configuration, using a numerical scheme to more accurately compute the horizontal advection in abrupt terrains, substantially improved the model performance.

Construction Method of the Topographical Features Model for Underwater Terrain Navigation

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Wang Lihui

2015-09-01

Full Text Available Terrain database is the reference basic for autonomous underwater vehicle (AUV to implement underwater terrain navigation (UTN functions, and is the important part of building topographical features model for UTN. To investigate the feasibility and correlation of a variety of terrain parameters as terrain navigation information metrics, this paper described and analyzed the underwater terrain features and topography parameters calculation method. Proposing a comprehensive evaluation method for terrain navigation information, and constructing an underwater navigation information analysis model, which is associated with topographic features. Simulation results show that the underwater terrain features, are associated with UTN information directly or indirectly, also affect the terrain matching capture probability and the positioning accuracy directly.

Terrain-Toolkit

DEFF Research Database (Denmark)

Wang, Qi; Kaul, Manohar; Long, Cheng

2014-01-01

, as will be shown, is used heavily for query processing in spatial databases; and (3) they do not provide the surface distance operator which is fundamental for many applications based on terrain data. Motivated by this, we developed a tool called Terrain-Toolkit for terrain data which accepts a comprehensive set......Terrain data is becoming increasingly popular both in industry and in academia. Many tools have been developed for visualizing terrain data. However, we find that (1) they usually accept very few data formats of terrain data only; (2) they do not support terrain simplification well which...

Sculpting Mountains: Interactive Terrain Modeling Based on Subsurface Geology.

Science.gov (United States)

Cordonnier, Guillaume; Cani, Marie-Paule; Benes, Bedrich; Braun, Jean; Galin, Eric

2018-05-01

Most mountain ranges are formed by the compression and folding of colliding tectonic plates. Subduction of one plate causes large-scale asymmetry while their layered composition (or stratigraphy) explains the multi-scale folded strata observed on real terrains. We introduce a novel interactive modeling technique to generate visually plausible, large scale terrains that capture these phenomena. Our method draws on both geological knowledge for consistency and on sculpting systems for user interaction. The user is provided hands-on control on the shape and motion of tectonic plates, represented using a new geologically-inspired model for the Earth crust. The model captures their volume preserving and complex folding behaviors under collision, causing mountains to grow. It generates a volumetric uplift map representing the growth rate of subsurface layers. Erosion and uplift movement are jointly simulated to generate the terrain. The stratigraphy allows us to render folded strata on eroded cliffs. We validated the usability of our sculpting interface through a user study, and compare the visual consistency of the earth crust model with geological simulation results and real terrains.

Local-scale stratigraphy of grooved terrain on Ganymede

Science.gov (United States)

Murchie, Scott L.; Head, James W.; Helfenstein, Paul; Plescia, Jeffrey B.

1987-01-01

The surface of the Jovian satellite, Ganymede, is divided into two main units, dark terrain cut by arcuate and subradial furrows, and light terrain consisting largely of areas with pervasive U-shaped grooves. The grooved terrain may be subdivided on the basis of pervasive morphology of groove domains into four terrain types: (1) elongate bands of parallel grooves (groove lanes); (2) polygonal domains of parallel grooves (grooved polygons); (3) polygonal domains of two orthogonal groove sets (reticulate terrain); and (4) polygons having two to several complexly cross-cutting groove sets (complex grooved terrain). Reticulate terrain is frequently dark and not extensively resurfaced, and grades to a more hummocky terrain type. The other three grooved terrain types have almost universally been resurfaced by light material during their emplacement. The sequence of events during grooved terrain emplacement has been investigated. An attempt is made to integrate observed geologic and tectonic patterns to better constrain the relative ages and styles of emplacement of grooved terrain types. A revised model of grooved terrain emplacement is proposed and is tested using detailed geologic mapping and measurement of crater density.

Digital terrain data base - new possibilities of 3D terrain modeling

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Mateja Rihtaršič

1992-12-01

Full Text Available GISs has brought new dimensions in the field of digital terrain modelling, too. Modem DTMs must be real (relational databases with high degree of "intelligence". This paper presents some of the demands, ivhich have to be solved in modern digital terrain databases, together with main steps of their's generation. Problems, connected to regional level, multi-pur pose use, new possibilities and direct integration into GIS are presented. The practical model was created across smaller test area, so few lines with practical experiences can be droped, too.

Experimental study and large eddy simulation of effect of terrain slope on marginal burning in shrub fuel beds

Science.gov (United States)

Xiangyang Zhou; Shankar Mahalingam; David Weise

2007-01-01

This paper presents a combined study of laboratory scale fire spread experiments and a three-dimensional large eddy simulation (LES) to analyze the effect of terrain slope on marginal burning behavior in live chaparral shrub fuel beds. Line fire was initiated in single species fuel beds of four common chaparral plants under various fuel bed configurations and ambient...

Analyzing complex wake-terrain interactions and its implications on wind-farm performance.

Science.gov (United States)

Tabib, Mandar; Rasheed, Adil; Fuchs, Franz

2016-09-01

Rotating wind turbine blades generate complex wakes involving vortices (helical tip-vortex, root-vortex etc.).These wakes are regions of high velocity deficits and high turbulence intensities and they tend to degrade the performance of down-stream turbines. Hence, a conservative inter-turbine distance of up-to 10 times turbine diameter (10D) is sometimes used in wind-farm layout (particularly in cases of flat terrain). This ensures that wake-effects will not reduce the overall wind-farm performance, but this leads to larger land footprint for establishing a wind-farm. In-case of complex-terrain, within a short distance (say 10D) itself, the nearby terrain can rise in altitude and be high enough to influence the wake dynamics. This wake-terrain interaction can happen either (a) indirectly, through an interaction of wake (both near tip vortex and far wake large-scale vortex) with terrain induced turbulence (especially, smaller eddies generated by small ridges within the terrain) or (b) directly, by obstructing the wake-region partially or fully in its flow-path. Hence, enhanced understanding of wake- development due to wake-terrain interaction will help in wind farm design. To this end the current study involves: (1) understanding the numerics for successful simulation of vortices, (2) understanding fundamental vortex-terrain interaction mechanism through studies devoted to interaction of a single vortex with different terrains, (3) relating influence of vortex-terrain interactions to performance of a wind-farm by studying a multi-turbine wind-farm layout under different terrains. The results on interaction of terrain and vortex has shown a much faster decay of vortex for complex terrain compared to a flatter-terrain. The potential reasons identified explaining the observation are (a) formation of secondary vortices in flow and its interaction with the primary vortex and (b) enhanced vorticity diffusion due to increased terrain-induced turbulence. The implications of

Adding complex terrain and stable atmospheric condition capability to the OpenFOAM-based flow solver of the simulator for on/offshore wind farm applications (SOWFA

Directory of Open Access Journals (Sweden)

Churchfield Matthew J.

2014-01-01

Full Text Available The National Renewable Energy Laboratory's Simulator for On/Offshore Wind Farm Applications contains an OpenFOAM-based flow solver for performing large-eddy simulation of flow through wind plants. The solver computes the atmospheric boundary layer flow and models turbines with actuator lines. Until recently, the solver was limited to flows over flat terrain and could only use the standard Smagorinsky subgrid-scale model. In this work, we present our improvements to the flow solver that enable us to 1 use any OpenFOAM-standard subgrid-scale model and 2 simulate flow over complex terrain. We used the flow solver to compute a stably stratified atmospheric boundary layer using both the standard and the Lagrangian-averaged scale-independent dynamic Smagorinsky models. Surprisingly, the results using the standard Smagorinsky model compare well to other researchers' results of the same case, although it is often said that the standard Smagorinsky model is too dissipative for accurate stable stratification calculations. The scale-independent dynamic subgrid-scale model produced poor results, probably due to the spikes in model constant with values as high as 4.6. We applied a simple bounding of the model constant to remove these spikes, which caused the model to produce results much more in line with other researchers' results. We also computed flow over a simple hilly terrain and performed some basic qualitative analysis to verify the proper operation of the terrain-local surface stress model we employed.

Complex terrain and wind lidars

Energy Technology Data Exchange (ETDEWEB)

Bingoel, F.

2009-08-15

This thesis includes the results of a PhD study about complex terrain and wind lidars. The study mostly focuses on hilly and forested areas. Lidars have been used in combination with cups, sonics and vanes, to reach the desired vertical measurement heights. Several experiments are performed in complex terrain sites and the measurements are compared with two different flow models; a linearised flow model LINCOM and specialised forest model SCADIS. In respect to the lidar performance in complex terrain, the results showed that horizontal wind speed errors measured by a conically scanning lidar can be of the order of 3-4% in moderately-complex terrain and up to 10% in complex terrain. The findings were based on experiments involving collocated lidars and meteorological masts, together with flow calculations over the same terrains. The lidar performance was also simulated with the commercial software WAsP Engineering 2.0 and was well predicted except for some sectors where the terrain is particularly steep. Subsequently, two experiments were performed in forested areas; where the measurements are recorded at a location deep-in forest and at the forest edge. Both sites were modelled with flow models and the comparison of the measurement data with the flow model outputs showed that the mean wind speed calculated by LINCOM model was only reliable between 1 and 2 tree height (h) above canopy. The SCADIS model reported better correlation with the measurements in forest up to approx6h. At the forest edge, LINCOM model was used by allocating a slope half-in half out of the forest based on the suggestions of previous studies. The optimum slope angle was reported as 17 deg.. Thus, a suggestion was made to use WAsP Engineering 2.0 for forest edge modelling with known limitations and the applied method. The SCADIS model worked better than the LINCOM model at the forest edge but the model reported closer results to the measurements at upwind than the downwind and this should be

Wind farm layout optimization in complex terrain: A preliminary study on a Gaussian hill

DEFF Research Database (Denmark)

Feng, Ju; Shen, Wen Zhong

2014-01-01

this problem for WFs in flat terrain or offshore has been investigated in many studies, it is still a challenging problem for WFs in complex terrain. In this preliminary study, the wind flow conditions of complex terrain without WTs are first obtained from computational fluid dynamics (CFD) simulation...

Preduction of Vehicle Mobility on Large-Scale Soft-Soil Terrain Maps Using Physics-Based Simulation

Science.gov (United States)

2016-08-02

Mechergui, Srinivas Sanikommu UNCLASSIFIED: Distribution Statement A. Approved for public release; distribution is unlimited. (#28138) Outline • Motivation ...Distribution Statement A. Approved for public release; distribution is unlimited. (#28138) Motivation /NRMM • Mobility measures include: – Speed-made...Index (CI). – Terrain uphill grade. • Rest of the terrain parameters will be considered in future work. 4 Terrain map (22 km x 22 km) colored by

High resolution simulations of orographic flow over a complex terrain on the Southeast coast of Brazil

Science.gov (United States)

Chou, S. C.; Zolino, M. M.; Gomes, J. L.; Bustamante, J. F.; Lima-e-Silva, P. P.

2012-04-01

The Eta Model is used operationally by CPTEC to produce weather forecasts over South America since 1997. The model has gone through upgrades. In order to prepare the model for operational higher resolution forecasts, the model is configured and tested over a region of complex topography located near the coast of Southeast Brazil. The Eta Model was configured, with 2-km horizontal resolution and 50 layers. The Eta-2km is a second nesting, it is driven by Eta-15km, which in its turn is driven by Era-Interim reanalyses. The model domain includes the two Brazilians cities, Rio de Janeiro and Sao Paulo, urban areas, preserved tropical forest, pasture fields, and complex terrain and coastline. Mountains can rise up to about 700m. The region suffers frequent events of floods and landslides. The objective of this work is to evaluate high resolution simulations of wind and temperature in this complex area. Verification of model runs uses observations taken from the nuclear power plant. Accurate near-surface wind direction and magnitude are needed for the plant emergency plan and winds are highly sensitive to model spatial resolution and atmospheric stability. Verification of two cases during summer shows that model has clear diurnal cycle signal for wind in that region. The area is characterized by weak winds which makes the simulation more difficult. The simulated wind magnitude is about 1.5m/s, which is close to observations of about 2m/s; however, the observed change of wind direction of the sea breeze is fast whereas it is slow in the simulations. Nighttime katabatic flow is captured by the simulations. Comparison against Eta-5km runs show that the valley circulation is better described in the 2-km resolution run. Simulated temperatures follow closely the observed diurnal cycle. Experiments improving some surface conditions such as the surface temperature and land cover show simulation error reduction and improved diurnal cycle.

Self-Supervised Learning of Terrain Traversability from Proprioceptive Sensors

Science.gov (United States)

Bajracharya, Max; Howard, Andrew B.; Matthies, Larry H.

2009-01-01

Robust and reliable autonomous navigation in unstructured, off-road terrain is a critical element in making unmanned ground vehicles a reality. Existing approaches tend to rely on evaluating the traversability of terrain based on fixed parameters obtained via testing in specific environments. This results in a system that handles the terrain well that it trained in, but is unable to process terrain outside its test parameters. An adaptive system does not take the place of training, but supplements it. Whereas training imprints certain environments, an adaptive system would imprint terrain elements and the interactions amongst them, and allow the vehicle to build a map of local elements using proprioceptive sensors. Such sensors can include velocity, wheel slippage, bumper hits, and accelerometers. Data obtained by the sensors can be compared to observations from ranging sensors such as cameras and LADAR (laser detection and ranging) in order to adapt to any kind of terrain. In this way, it could sample its surroundings not only to create a map of clear space, but also of what kind of space it is and its composition. By having a set of building blocks consisting of terrain features, a vehicle can adapt to terrain that it has never seen before, and thus be robust to a changing environment. New observations could be added to its library, enabling it to infer terrain types that it wasn't trained on. This would be very useful in alien environments, where many of the physical features are known, but some are not. For example, a seemingly flat, hard plain could actually be soft sand, and the vehicle would sense the sand and avoid it automatically.

Ranging error analysis of single photon satellite laser altimetry under different terrain conditions

Science.gov (United States)

Huang, Jiapeng; Li, Guoyuan; Gao, Xiaoming; Wang, Jianmin; Fan, Wenfeng; Zhou, Shihong

2018-02-01

Single photon satellite laser altimeter is based on Geiger model, which has the characteristics of small spot, high repetition rate etc. In this paper, for the slope terrain, the distance of error's formula and numerical calculation are carried out. Monte Carlo method is used to simulate the experiment of different terrain measurements. The experimental results show that ranging accuracy is not affected by the spot size under the condition of the flat terrain, But the inclined terrain can influence the ranging error dramatically, when the satellite pointing angle is 0.001° and the terrain slope is about 12°, the ranging error can reach to 0.5m. While the accuracy can't meet the requirement when the slope is more than 70°. Monte Carlo simulation results show that single photon laser altimeter satellite with high repetition rate can improve the ranging accuracy under the condition of complex terrain. In order to ensure repeated observation of the same point for 25 times, according to the parameters of ICESat-2, we deduce the quantitative relation between the footprint size, footprint, and the frequency repetition. The related conclusions can provide reference for the design and demonstration of the domestic single photon laser altimetry satellite.

Numerical simulation of terrain-induced mesoscale circulation in the Chiang Mai area, Thailand

Science.gov (United States)

Sathitkunarat, Surachai; Wongwises, Prungchan; Pan-Aram, Rudklao; Zhang, Meigen

2008-11-01

The regional atmospheric modeling system (RAMS) was applied to Chiang Mai province, a mountainous area in Thailand, to study terrain-induced mesoscale circulations. Eight cases in wet and dry seasons under different weather conditions were analyzed to show thermal and dynamic impacts on local circulations. This is the first study of RAMS in Thailand especially investigating the effect of mountainous area on the simulated meteorological data. Analysis of model results indicates that the model can reproduce major features of local circulation and diurnal variations in temperatures. For evaluating the model performance, model results were compared with observed wind speed, wind direction, and temperature monitored at a meteorological tower. Comparison shows that the modeled values are generally in good agreement with observations and that the model captured many of the observed features.

Numerical simulation of flow over bariers in complex terrain

Czech Academy of Sciences Publication Activity Database

Bodnár, Tomáš; Beneš, L.; Kozel, Karel

2008-01-01

Roč. 31, 5-6 (2008), s. 619-632 ISSN 1124-1896 R&D Projects: GA AV ČR 1ET400760405 Institutional research plan: CEZ:AV0Z20760514 Keywords : boundary layer * complex terrain * finite difference Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 0.277, year: 2008 http://prometeo.sif.it:8080/papers/?pid=ncc9331

New non-orthogonality treatment for atmospheric boundary layer flow simulation above highly non-uniform terrains

Directory of Open Access Journals (Sweden)

Mirkov Nikola S.

2016-01-01

Full Text Available In this paper we validate an improved finite volume approximation of Reynolds Averaged Navier-Stokes equations for simulation of wind flows in body-fitted grids generated by algebraic extrusion from digital terrain elevation data, proposed in N. Mirkov et. al. J. Comput. Phys. 287, 18-45(2015, [1]. The approach is based on second-order accurate finite volume method with collocated variable arrangement and pressure-velocity coupling trough SIMPLE algorithm. The main objective is the attenuation of spurious pressure field oscillations in regions with discontinuity in grid line slopes, as encountered in grids representing highly non-uniform terrains. Moreover, the approach relaxes the need for grid generation based on elliptic PDEs or grid smoothing by applying fixed point iterations (i.e. Gauss-Seidel to initial grid node positions resulting from algebraic grid generators. Drawbacks of previous approaches which ignored treatment of finite volume grid cell cases with intersection point offset in non-orthogonality corrections are removed. Application to real-life wind farm project at Dobrič (Srvljig, Serbia is used to assess the effectiveness of the method. The results validate the view in which accurate discretization of governing equations play more important role than the choice of turbulence modelling closures. [Projekat Ministarstva nauke Republike Srbije, br. TR-33036

Simulation of Wind Farms in Flat & Complex terrain using CFD

DEFF Research Database (Denmark)

Prospathopoulos, John; Cabezon, D.; Politis, E.S.

2010-01-01

, the combination of the induction factor method along with the turbulence correction provides satisfactory results. In the complex terrain case, there are some significant discrepancies with the measurements, which are discussed. In this case, the induction factor method does not provide satisfactory results....

Rapid Optimal Generation Algorithm for Terrain Following Trajectory Based on Optimal Control

Institute of Scientific and Technical Information of China (English)

杨剑影; 张海; 谢邦荣; 尹健

2004-01-01

Based on the optimal control theory, a 3-dimensionnal direct generation algorithm is proposed for anti-ground low altitude penetration tasks under complex terrain. By optimizing the terrain following(TF) objective function,terrain coordinate system, missile dynamic model and control vector, the TF issue is turning into the improved optimal control problem whose mathmatical model is simple and need not solve the second order terrain derivative. Simulation results prove that this method is reasonable and feasible. The TF precision is in the scope from 0.3 m to 3.0 m,and the planning time is less than 30 min. This method have the strongpionts such as rapidness, precision and has great application value.

Numerical simulation of turbulent convective flow over wavy terrain

Science.gov (United States)

Dörnbrack, A.; Schumann, U.

1993-09-01

By means of a large-eddy simulation, the convective boundary layer is investigated for flows over wavy terrain. The lower surface varies sinusoidally in the downstream direction while remaining constant in the other. Several cases are considered with amplitude δ up to 0.15 H and wavelength λ of H to 8 H, where H is the mean fluid-layer height. At the lower surface, the vertical heat flux is prescribed to be constant and the momentum flux is determined locally from the Monin-Obukhov relationship with a roughness length z o=10-4 H. The mean wind is varied between zero and 5 w *, where w * is the convective velocity scale. After rather long times, the flow structure shows horizontal scales up to 4 H, with a pattern similar to that over flat surfaces at corresponding shear friction. Weak mean wind destroys regular spatial structures induced by the surface undulation at zero mean wind. The surface heating suppresses mean-flow recirculation-regions even for steep surface waves. Short surface waves cause strong drag due to hydrostatic and dynamic pressure forces in addition to frictional drag. The pressure drag increases slowly with the mean velocity, and strongly with δ/ H. The turbulence variances increase mainly in the lower half of the mixed layer for U/w *>2.

CFD three dimensional wake analysis in complex terrain

Science.gov (United States)

Castellani, F.; Astolfi, D.; Terzi, L.

2017-11-01

Even if wind energy technology is nowadays fully developed, the use of wind energy in very complex terrain is still challenging. In particular, it is challenging to characterize the combination effects of wind ow over complex terrain and wake interactions between nearby turbines and this has a practical relevance too, for the perspective of mitigating anomalous vibrations and loads as well improving the farm efficiency. In this work, a very complex terrain site has been analyzed through a Reynolds-averaged CFD (Computational Fluid Dynamics) numerical wind field model; in the simulation the inuence of wakes has been included through the Actuator Disk (AD) approach. In particular, the upstream turbine of a cluster of 4 wind turbines having 2.3 MW of rated power is studied. The objective of this study is investigating the full three-dimensional wind field and the impact of three-dimensionality on the evolution of the waked area between nearby turbines. A post-processing method of the output of the CFD simulation is developed and this allows to estimate the wake lateral deviation and the wake width. The reliability of the numerical approach is inspired by and crosschecked through the analysis of the operational SCADA (Supervisory Control and Data Acquisition) data of the cluster of interest.

How fine is fine enough when doing CFD terrain simulations

DEFF Research Database (Denmark)

Sørensen, Niels N.; Bechmann, Andreas; Réthoré, Pierre-Elouan

2012-01-01

The present work addresses the problemof establishing the necessary grid resolution to obtain a given level of numerical accuracy using a CFD model for prediction of flow over terrain. It is illustrated, that a very high resolution may be needed if the numerical difference between consecutive...

Landing Control of Foot with Springs for Walking Robots on Rough Terrain

Directory of Open Access Journals (Sweden)

Moyuru Yamada

2009-09-01

Full Text Available Landing control is one of the important issues for biped walking robot, because robots are expected to walk on not only known flat surfaces but also unknown and uneven terrain for working at various fields. This paper presents a new controller design for a robotic foot to land on unknown terrain. The robotic foot considered in this study equips springs to reduce the impact force at the foot landing. There are two objectives in the landing control; achieving the desired ground reaction force and positioning the foot on unknown terrain. To achieve these two objectives simultaneously by adjusting the foot position, we propose a PI force controller with a desired foot position, which guarantees the robust stability of control system with respect to terrain variance, and exact positioning of the foot to unknown terrain. Simulation results using the Open Dynamics Engine demonstrate the effectiveness of the proposed controller.

Soft Soil Impact Testing and Simulation of Aerospace Structures

Science.gov (United States)

Fasanella, Edwin L.; Jackson, Karen E.; Kellas, Sotiris

2008-01-01

In June 2007, a 38-ft/s vertical drop test of a 5-ft-diameter, 5-ft-long composite fuselage section that was retrofitted with a novel composite honeycomb Deployable Energy Absorber (DEA) was conducted onto unpacked sand. This test was one of a series of tests to evaluate the multi-terrain capabilities of the DEA and to generate test data for model validation. During the test, the DEA crushed approximately 6-in. and left craters in the sand of depths ranging from 7.5- to 9-in. A finite element model of the fuselage section with DEA was developed for execution in LS-DYNA, a commercial nonlinear explicit transient dynamic code. Pre-test predictions were generated in which the sand was represented initially as a crushable foam material MAT_CRUSHABLE_FOAM (Mat 63). Following the drop test, a series of hemispherical penetrometer tests were conducted to assist in soil characterization. The penetrometer weighed 20-lb and was instrumented with a tri-axial accelerometer. Drop tests were performed at 16-ft/s and crater depths were measured. The penetrometer drop tests were simulated as a means for developing a more representative soil model based on a soil and foam material definition MAT_SOIL_AND FOAM (Mat 5) in LS-DYNA. The model of the fuselage with DEA was reexecuted using the updated soil model and test-analysis correlations are presented.

Laser altimetry and terrain analysis: A revolution in geomorphology

NARCIS (Netherlands)

Anders, N.; Seijmonsbergen, H.

2008-01-01

Terrain analysis in geomorphology has undergone a serious quantitative revolution over recent decades. Lidar information has been efficiently used to automatically classify discrete landforms, map forest structures, and provide input for models simulating landscape development, e.g. channel incision

Dynamic Modeling and Vibration Analysis for the Vehicles with Rigid Wheels Based on Wheel-Terrain Interaction Mechanics

Directory of Open Access Journals (Sweden)

Jianfeng Wang

2015-01-01

Full Text Available The contact mechanics for a rigid wheel and deformable terrain are complicated owing to the rigid flexible coupling characteristics. Bekker’s equations are used as the basis to establish the equations of the sinking rolling wheel, to vertical load pressure relationship. Since vehicle movement on the Moon is a complex and on-going problem, the researcher is poised to simplify this problem of vertical loading of the wheel. In this paper, the quarter kinetic models of a manned lunar rover, which are both based on the rigid road and deformable lunar terrain, are used as the simulation models. With these kinetic models, the vibration simulations were conducted. The simulation results indicate that the quarter kinetic model based on the deformable lunar terrain accurately reflects the deformable terrain’s influence on the vibration characteristics of a manned lunar rover. Additionally, with the quarter kinetic model of the deformable terrain, the vibration simulations of a manned lunar rover were conducted, which include a parametric analysis of the wheel parameters, vehicle speed, and suspension parameters. The results show that a manned lunar rover requires a lower damping value and stiffness to achieve better vibration performance.

A spatially explicit hydro-ecological modeling framework (BEPS-TerrainLab V2.0): Model description and test in a boreal ecosystem in Eastern North America

Science.gov (United States)

Govind, Ajit; Chen, Jing Ming; Margolis, Hank; Ju, Weimin; Sonnentag, Oliver; Giasson, Marc-André

2009-04-01

SummaryA spatially explicit, process-based hydro-ecological model, BEPS-TerrainLab V2.0, was developed to improve the representation of ecophysiological, hydro-ecological and biogeochemical processes of boreal ecosystems in a tightly coupled manner. Several processes unique to boreal ecosystems were implemented including the sub-surface lateral water fluxes, stratification of vegetation into distinct layers for explicit ecophysiological representation, inclusion of novel spatial upscaling strategies and biogeochemical processes. To account for preferential water fluxes common in humid boreal ecosystems, a novel scheme was introduced based on laboratory analyses. Leaf-scale ecophysiological processes were upscaled to canopy-scale by explicitly considering leaf physiological conditions as affected by light and water stress. The modified model was tested with 2 years of continuous measurements taken at the Eastern Old Black Spruce Site of the Fluxnet-Canada Research Network located in a humid boreal watershed in eastern Canada. Comparison of the simulated and measured ET, water-table depth (WTD), volumetric soil water content (VSWC) and gross primary productivity (GPP) revealed that BEPS-TerrainLab V2.0 simulates hydro-ecological processes with reasonable accuracy. The model was able to explain 83% of the ET, 92% of the GPP variability and 72% of the WTD dynamics. The model suggests that in humid ecosystems such as eastern North American boreal watersheds, topographically driven sub-surface baseflow is the main mechanism of soil water partitioning which significantly affects the local-scale hydrological conditions.

VHF/UHF imagery and RCS measurements of ground targets in forested terrain

Science.gov (United States)

Gatesman, Andrew J.; Beaudoin, Christopher J.; Giles, Robert H.; Waldman, Jerry; Nixon, William E.

2002-08-01

The monostatic VV and HH-polarized radar signatures of several targets and trees have been measured at foliage penetration frequencies (VHF/UHF) by using 1/35th scale models and an indoor radar range operating at X-band. An array of high-fidelity scale model ground vehicles and test objects as well as scaled ground terrain and trees have been fabricated for the study. Radar measurement accuracy has been confirmed by comparing the signature of a test object with a method of moments radar cross section prediction code. In addition to acquiring signatures of targets located on a smooth, dielectric ground plane, data have also been acquired with targets located in simulated wooded terrain that included scaled tree trunks and tree branches. In order to assure the correct backscattering behavior, all dielectric properties of live tree wood and moist soil were scaled properly to match the complex dielectric constant of the full-scale materials. The impact of the surrounding tree clutter on the VHF/UHF radar signatures of ground vehicles was accessed. Data were processed into high-resolution, polar-formatted ISAR imagery and signature comparisons are made between targets in open-field and forested scenarios.

A Virtual Simulation Environment for Lunar Rover: Framework and Key Technologies

Directory of Open Access Journals (Sweden)

Yan-chun Yang

2008-11-01

Full Text Available Lunar rover development involves a large amount of validation works in realistic operational conditions, including its mechanical subsystem and on-board software. Real tests require equipped rover platform and a realistic terrain. It is very time consuming and high cost. To improve the development efficiency, a rover simulation environment called RSVE that affords real time capabilities with high fidelity has been developed. It uses fractional Brown motion (fBm technique and statistical properties to generate lunar surface. Thus, various terrain models for simulation can be generated through changing several parameters. To simulate lunar rover evolving on natural and unstructured surface with high realism, the whole dynamics of the multi-body systems and complex interactions with soft ground is integrated in this environment. An example for path planning algorithm and controlling algorithm testing in this environment is tested. This simulation environment runs on PC or Silicon Graphics.

A Virtual Simulation Environment for Lunar Rover: Framework and Key Technologies

Directory of Open Access Journals (Sweden)

Yan-chun Yang

2008-06-01

Full Text Available Lunar rover development involves a large amount of validation works in realistic operational conditions, including its mechanical subsystem and on-board software. Real tests require equipped rover platform and a realistic terrain. It is very time consuming and high cost. To improve the development efficiency, a rover simulation environment called RSVE that affords real time capabilities with high fidelity has been developed. It uses fractional Brown motion (fBm technique and statistical properties to generate lunar surface. Thus, various terrain models for simulation can be generated through changing several parameters. To simulate lunar rover evolving on natural and unstructured surface with high realism, the whole dynamics of the multi-body systems and complex interactions with soft ground is integrated in this environment. An example for path planning algorithm and controlling algorithm testing in this environment is tested. This simulation environment runs on PC or Silicon Graphics.

Realistic terrain visualization based on 3D virtual world technology

Science.gov (United States)

Huang, Fengru; Lin, Hui; Chen, Bin; Xiao, Cai

2010-11-01

The rapid advances in information technologies, e.g., network, graphics processing, and virtual world, have provided challenges and opportunities for new capabilities in information systems, Internet applications, and virtual geographic environments, especially geographic visualization and collaboration. In order to achieve meaningful geographic capabilities, we need to explore and understand how these technologies can be used to construct virtual geographic environments to help to engage geographic research. The generation of three-dimensional (3D) terrain plays an important part in geographical visualization, computer simulation, and virtual geographic environment applications. The paper introduces concepts and technologies of virtual worlds and virtual geographic environments, explores integration of realistic terrain and other geographic objects and phenomena of natural geographic environment based on SL/OpenSim virtual world technologies. Realistic 3D terrain visualization is a foundation of construction of a mirror world or a sand box model of the earth landscape and geographic environment. The capabilities of interaction and collaboration on geographic information are discussed as well. Further virtual geographic applications can be developed based on the foundation work of realistic terrain visualization in virtual environments.

Laboratory simulations of the atmospheric mixed layer in flow over complex terrain

Data.gov (United States)

U.S. Environmental Protection Agency — A laboratory study of the influence of complex terrain on the interface between a well-mixed boundary layer and an elevated stratified layer was conducted in the...

Periodic spring–mass running over uneven terrain through feedforward control of landing conditions

International Nuclear Information System (INIS)

III, Luther R Palmer; Eaton, Caitrin E

2014-01-01

This work pursues a feedforward control algorithm for high-speed legged locomotion over uneven terrain. Being able to rapidly negotiate uneven terrain without visual or a priori information about the terrain will allow legged systems to be used in time-critical applications and alongside fast-moving humans or vehicles. The algorithm is shown here implemented on a spring-loaded inverted pendulum model in simulation, and can be configured to approach fixed running height over uneven terrain or self-stable terrain following. Offline search identifies unique landing conditions that achieve a desired apex height with a constant stride period over varying ground levels. Because the time between the apex and touchdown events is directly related to ground height, the landing conditions can be computed in real time as continuous functions of this falling time. Enforcing a constant stride period reduces the need for inertial sensing of the apex event, which is nontrivial for physical systems, and allows for clocked feedfoward control of the swing leg. (paper)

Periodic spring-mass running over uneven terrain through feedforward control of landing conditions.

Science.gov (United States)

Palmer, Luther R; Eaton, Caitrin E

2014-09-01

This work pursues a feedforward control algorithm for high-speed legged locomotion over uneven terrain. Being able to rapidly negotiate uneven terrain without visual or a priori information about the terrain will allow legged systems to be used in time-critical applications and alongside fast-moving humans or vehicles. The algorithm is shown here implemented on a spring-loaded inverted pendulum model in simulation, and can be configured to approach fixed running height over uneven terrain or self-stable terrain following. Offline search identifies unique landing conditions that achieve a desired apex height with a constant stride period over varying ground levels. Because the time between the apex and touchdown events is directly related to ground height, the landing conditions can be computed in real time as continuous functions of this falling time. Enforcing a constant stride period reduces the need for inertial sensing of the apex event, which is nontrivial for physical systems, and allows for clocked feedfoward control of the swing leg.

Information measures for terrain visualization

Science.gov (United States)

Bonaventura, Xavier; Sima, Aleksandra A.; Feixas, Miquel; Buckley, Simon J.; Sbert, Mateu; Howell, John A.

2017-02-01

Many quantitative and qualitative studies in geoscience research are based on digital elevation models (DEMs) and 3D surfaces to aid understanding of natural and anthropogenically-influenced topography. As well as their quantitative uses, the visual representation of DEMs can add valuable information for identifying and interpreting topographic features. However, choice of viewpoints and rendering styles may not always be intuitive, especially when terrain data are augmented with digital image texture. In this paper, an information-theoretic framework for object understanding is applied to terrain visualization and terrain view selection. From a visibility channel between a set of viewpoints and the component polygons of a 3D terrain model, we obtain three polygonal information measures. These measures are used to visualize the information associated with each polygon of the terrain model. In order to enhance the perception of the terrain's shape, we explore the effect of combining the calculated information measures with the supplementary digital image texture. From polygonal information, we also introduce a method to select a set of representative views of the terrain model. Finally, we evaluate the behaviour of the proposed techniques using example datasets. A publicly available framework for both the visualization and the view selection of a terrain has been created in order to provide the possibility to analyse any terrain model.

CALCULATION OF CHEMICAL ATMOSPHERE ESTIMATION GIVEN THE COMPLEX TERRAIN

Directory of Open Access Journals (Sweden)

M. M. Biliaiev

2010-06-01

Full Text Available The 3D numerical model was used to simulate the toxic gas dispersion over a complex terrain after an accident spillage. The model is based on the K-gradient transport model and the model of potential flow. The results of numerical experiment are presented.

TopoSCALE v.1.0: downscaling gridded climate data in complex terrain

Science.gov (United States)

Fiddes, J.; Gruber, S.

2014-02-01

Simulation of land surface processes is problematic in heterogeneous terrain due to the the high resolution required of model grids to capture strong lateral variability caused by, for example, topography, and the lack of accurate meteorological forcing data at the site or scale it is required. Gridded data products produced by atmospheric models can fill this gap, however, often not at an appropriate spatial resolution to drive land-surface simulations. In this study we describe a method that uses the well-resolved description of the atmospheric column provided by climate models, together with high-resolution digital elevation models (DEMs), to downscale coarse-grid climate variables to a fine-scale subgrid. The main aim of this approach is to provide high-resolution driving data for a land-surface model (LSM). The method makes use of an interpolation of pressure-level data according to topographic height of the subgrid. An elevation and topography correction is used to downscale short-wave radiation. Long-wave radiation is downscaled by deriving a cloud-component of all-sky emissivity at grid level and using downscaled temperature and relative humidity fields to describe variability with elevation. Precipitation is downscaled with a simple non-linear lapse and optionally disaggregated using a climatology approach. We test the method in comparison with unscaled grid-level data and a set of reference methods, against a large evaluation dataset (up to 210 stations per variable) in the Swiss Alps. We demonstrate that the method can be used to derive meteorological inputs in complex terrain, with most significant improvements (with respect to reference methods) seen in variables derived from pressure levels: air temperature, relative humidity, wind speed and incoming long-wave radiation. This method may be of use in improving inputs to numerical simulations in heterogeneous and/or remote terrain, especially when statistical methods are not possible, due to lack of

On characterizing terrain visibility graphs

Directory of Open Access Journals (Sweden)

William Evans

2015-06-01

Full Text Available A terrain is an $x$-monotone polygonal line in the $xy$-plane. Two vertices of a terrain are mutually visible if and only if there is no terrain vertex on or above the open line segment connecting them. A graph whose vertices represent terrain vertices and whose edges represent mutually visible pairs of terrain vertices is called a terrain visibility graph. We would like to find properties that are both necessary and sufficient for a graph to be a terrain visibility graph; that is, we would like to characterize terrain visibility graphs.Abello et al. [Discrete and Computational Geometry, 14(3:331--358, 1995] showed that all terrain visibility graphs are “persistent”. They showed that the visibility information of a terrain point set implies some ordering requirements on the slopes of the lines connecting pairs of points in any realization, and as a step towards showing sufficiency, they proved that for any persistent graph $M$ there is a total order on the slopes of the (pseudo lines in a generalized configuration of points whose visibility graph is $M$.We give a much simpler proof of this result by establishing an orientation to every triple of vertices, reflecting some slope ordering requirements that are consistent with $M$ being the visibility graph, and prove that these requirements form a partial order. We give a faster algorithm to construct a total order on the slopes. Our approach attempts to clarify the implications of the graph theoretic properties on the ordering of the slopes, and may be interpreted as defining properties on an underlying oriented matroid that we show is a restricted type of $3$-signotope.

Simulation of wind-induced snow transport in alpine terrain using a fully coupled snowpack/atmosphere model

Science.gov (United States)

Vionnet, V.; Martin, E.; Masson, V.; Guyomarc'h, G.; Naaim-Bouvet, F.; Prokop, A.; Durand, Y.; Lac, C.

2013-06-01

In alpine regions, wind-induced snow transport strongly influences the spatio-temporal evolution of the snow cover throughout the winter season. To gain understanding on the complex processes that drive the redistribution of snow, a new numerical model is developed. It couples directly the detailed snowpack model Crocus with the atmospheric model Meso-NH. Meso-NH/Crocus simulates snow transport in saltation and in turbulent suspension and includes the sublimation of suspended snow particles. A detailed representation of the first meters of the atmosphere allows a fine reproduction of the erosion and deposition process. The coupled model is evaluated against data collected around the experimental site of Col du Lac Blanc (2720 m a.s.l., French Alps). For this purpose, a blowing snow event without concurrent snowfall has been selected and simulated. Results show that the model captures the main structures of atmospheric flow in alpine terrain, the vertical profile of wind speed and the snow particles fluxes near the surface. However, the horizontal resolution of 50 m is found to be insufficient to simulate the location of areas of snow erosion and deposition observed by terrestrial laser scanning. When activated, the sublimation of suspended snow particles causes a reduction in deposition of 5.3%. Total sublimation (surface + blowing snow) is three times higher than surface sublimation in a simulation neglecting blowing snow sublimation.

Real-Time Human in the Loop MBS Simulation in the Fraunhofer Robot-Based Driving Simulator

Directory of Open Access Journals (Sweden)

Kleer Michael

2014-08-01

Full Text Available The paper encompasses the overview of hardware architecture and the systems characteristics of the Fraunhofer driving simulator. First, the requirements of the real-time model and the real-time calculation hardware are defined and discussed in detail. Aspects like transport delay and the parallel computation of complex real-time models are presented. In addition, the interfacing of the models with the simulator system is shown. Two simulator driving tests, including a fully interactive rough terrain driving with a wheeled excavator and a test drive with a passenger car, are set to demonstrate system characteristics. Furthermore, the simulator characteristics of practical significance, such as simulator response time delay, simulator acceleration signal bandwidth obtained from artificial excitation and from the simulator driving test, will be presented and discussed.

Knowledge-inducing Global Path Planning for Robots in Environment with Hybrid Terrain

Directory of Open Access Journals (Sweden)

Yi-nan Guo

2010-09-01

Full Text Available In complex environment with hybrid terrain, different regions may have different terrain. Path planning for robots in such environment is an open NP-complete problem, which lacks effective methods. The paper develops a novel global path planning method based on common sense and evolution knowledge by adopting dual evolution structure in culture algorithms. Common sense describes terrain information and feasibility of environment, which is used to evaluate and select the paths. Evolution knowledge describes the angle relationship between the path and the obstacles, or the common segments of paths, which is used to judge and repair infeasible individuals. Taken two types of environments with different obstacles and terrain as examples, simulation results indicate that the algorithm can effectively solve path planning problem in complex environment and decrease the computation complexity for judgment and repair of infeasible individuals. It also can improve the convergence speed and have better computation stability.

Validation of the simpleFoam (RANS solver for the atmospheric boundary layer in complex terrain

Directory of Open Access Journals (Sweden)

Peralta C.

2014-01-01

Full Text Available We validate the simpleFoam (RANS solver in OpenFOAM (version 2.1.1 for simulating neutral atmospheric boundary layer flows in complex terrain. Initial and boundary conditions are given using Richards and Hoxey proposal [1]. In order to obtain stable simulation of the ABL, modified wall functions are used to set the near-wall boundary conditions, following Blocken et al remedial measures [2]. A structured grid is generated with the new library terrainBlockMesher [3,4], based on OpenFOAM's blockMesh native mesher. The new tool is capable of adding orographic features and the forest canopy. Additionally, the mesh can be refined in regions with complex orography. We study both the classical benchmark case of Askervein hill [5] and the more recent Bolund island data set [6]. Our purpose is two-folded: to validate the performance of OpenFOAM steady state solvers, and the suitability of the new meshing tool to generate high quality structured meshes, which will be used in the future for performing more computationally intensive LES simulations in complex terrain.

Submarine Salt Karst Terrains

Directory of Open Access Journals (Sweden)

Nico Augustin

2016-06-01

Full Text Available Karst terrains that develop in bodies of rock salt (taken as mainly of halite, NaCl are special not only for developing in one of the most soluble of all rocks, but also for developing in one of the weakest rocks. Salt is so weak that many surface-piercing salt diapirs extrude slow fountains of salt that that gravity spread downslope over deserts on land and over sea floors. Salt fountains in the deserts of Iran are usually so dry that they flow at only a few cm/yr but the few rain storms a decade so soak and weaken them that they surge at dm/day for a few days. We illustrate the only case where the rates at which different parts of one of the many tens of subaerial salt karst terrains in Iran flows downslope constrains the rates at which its subaerial salt karst terrains form. Normal seawater is only 10% saturated in NaCl. It should therefore be sufficiently aggressive to erode karst terrains into exposures of salt on the thousands of known submarine salt extrusions that have flowed or are still flowing over the floors of hundreds of submarine basins worldwide. However, we know of no attempt to constrain the processes that form submarine salt karst terrains on any of these of submarine salt extrusions. As on land, many potential submarine karst terrains are cloaked by clastic and pelagic sediments that are often hundreds of m thick. Nevertheless, detailed geophysical and bathymetric surveys have already mapped likely submarine salt karst terrains in at least the Gulf of Mexico, and the Red Sea. New images of these two areas are offered as clear evidence of submarine salt dissolution due to sinking or rising aggressive fluids. We suggest that repeated 3D surveys of distinctive features (± fixed seismic reflectors of such terrains could measure any downslope salt flow and thus offer an exceptional opportunity to constrain the rates at which submarine salt karst terrains develop. Such rates are of interest to all salt tectonicians and the many

Are Titan's radial Labyrinth terrains surface expressions of large laccoliths?

Science.gov (United States)

Schurmeier, L.; Dombard, A. J.; Malaska, M.; Radebaugh, J.

2017-12-01

The Labyrinth terrain unit may be the one of the best examples of the surface expression of Titan's complicated history. They are characterized as highly eroded, dissected, and elevated plateaus and remnant ridges, with an assumed composition that is likely organic-rich based on radar emissivity. How these features accumulated organic-rich sediments and formed topographic highs by either locally uplifting or surviving pervasive regional deflation or erosion is an important question for understanding the history of Titan. There are several subsets of Labyrinth terrains, presumably with differing evolutionary histories and formation processes. We aim to explain the formation of a subset of Labyrinth terrain units informally referred to as "radial Labyrinth terrains." They are elevated and appear dome-like, circular in planform, have a strong radial dissection pattern, are bordered by Undifferentiated Plains units, and are found in the mid-latitudes. Based on their shape, clustering, and dimensions, we suggest that they may be the surface expression of large subsurface laccoliths. A recent study by Manga and Michaut (Icarus, 2017) explained Europa's lenticulae (pits, domes, spots) with the formation of saucer-shaped sills that form laccoliths around the brittle-ductile transition depth within the ice shell (1-5 km). Here, we apply the same scaling relationships and find that the larger size of radial labyrinth terrains with Titan's higher gravity implies deeper intrusion depths of around 20-40 km. This intrusion depth matches the expected brittle-ductile transition on Titan based on our finite element simulations and yield strength envelope analyses. We hypothesize that Titan's radial labyrinth terrains formed as cryovolcanic (water) intrusions that rose to the brittle-ductile transition within the ice shell where they spread horizontally, and uplifted the overlying ice. The organic-rich sedimentary cover also uplifted, becoming more susceptible to pluvial and fluvial

Spatial and temporal variability of hyperspectral signatures of terrain

Science.gov (United States)

Jones, K. F.; Perovich, D. K.; Koenig, G. G.

2008-04-01

Electromagnetic signatures of terrain exhibit significant spatial heterogeneity on a range of scales as well as considerable temporal variability. A statistical characterization of the spatial heterogeneity and spatial scaling algorithms of terrain electromagnetic signatures are required to extrapolate measurements to larger scales. Basic terrain elements including bare soil, grass, deciduous, and coniferous trees were studied in a quasi-laboratory setting using instrumented test sites in Hanover, NH and Yuma, AZ. Observations were made using a visible and near infrared spectroradiometer (350 - 2500 nm) and hyperspectral camera (400 - 1100 nm). Results are reported illustrating: i) several difference scenes; ii) a terrain scene time series sampled over an annual cycle; and iii) the detection of artifacts in scenes. A principal component analysis indicated that the first three principal components typically explained between 90 and 99% of the variance of the 30 to 40-channel hyperspectral images. Higher order principal components of hyperspectral images are useful for detecting artifacts in scenes.

The Effect of Terrain Inclination on Performance and the Stability Region of Two-Wheeled Mobile Robots

Directory of Open Access Journals (Sweden)

Zareena Kausar

2012-11-01

Full Text Available Two-wheeled mobile robots (TWMRs have a capability of avoiding the tip-over problem on inclined terrain by adjusting the centre of mass position of the robot body. The effects of terrain inclination on the robot performance are studied to exploit this capability. Prior to the real-time implementation of position control, an estimation of the stability region of the TWMR is essential for safe operation. A numerical method to estimate the stability region is applied and the effects of inclined surfaces on the performance and stability region of the robot are investigated. The dynamics of a TWMR is modelled on a general uneven terrain and reduced for cases of inclined and horizontal flat terrain. A full state feedback (FSFB controller is designed based on optimal gains with speed tracking on a horizontal flat terrain. The performance and stability regions are simulated for the robot on a horizontal flat and inclined terrain with the same controller. The results endorse a variation in equilibrium points and a reduction in stability region for robot motion on inclined terrain.

3D Fractal reconstruction of terrain profile data based on digital elevation model

International Nuclear Information System (INIS)

Huang, Y.M.; Chen, C.-J.

2009-01-01

Digital Elevation Model (DEM) often makes it difficult for terrain reconstruction and data storage due to the failure in acquisition of details with higher resolution. If original terrain of DEM can be simulated, resulting in geographical details can be represented precisely while reducing the data size, then an effective reconstruction scheme is essential. This paper adopts two sets of real-world 3D terrain profile data to proceed data reducing, i.e. data sampling randomly, then reconstruct them through 3D fractal reconstruction. Meanwhile, the quantitative and qualitative difference generated from different reduction rates were evaluated statistically. The research results show that, if 3D fractal interpolation method is applied to DEM reconstruction, the higher reduction rate can be obtained for DEM of larger data size with respect to that of smaller data size under the assumption that the entire terrain structure is still maintained.

Probing the Terrain

DEFF Research Database (Denmark)

Johannessen, Runa

2016-01-01

Whether manifest in built structures or invisible infrastructures, architectures of control in the occupied Palestinian West Bank is structurally defined by endemic uncertainty. Shifting lines and frontiers are recorded on the terrain, creating elastic zones of uncertainty necessitating navigatio...... to the territory through its lines and laws, and how the very structure of the occupation has changed over the years, I seek to make visible the ways in which architectures of uncertainty compensate for the fleeting terrain that HH is probing.......Whether manifest in built structures or invisible infrastructures, architectures of control in the occupied Palestinian West Bank is structurally defined by endemic uncertainty. Shifting lines and frontiers are recorded on the terrain, creating elastic zones of uncertainty necessitating...

An Approach to Stable Walking over Uneven Terrain Using a Reflex-Based Adaptive Gait

Directory of Open Access Journals (Sweden)

Umar Asif

2011-01-01

Full Text Available This paper describes the implementation of an adaptive gait in a six-legged walking robot that is capable of generating reactive stepping actions with the same underlying control methodology as an insect for stable walking over uneven terrains. The proposed method of gait generation uses feedback data from onboard sensors to generate an adaptive gait in order to surmount obstacles, gaps and perform stable walking. The paper addresses its implementation through simulations in a visual dynamic simulation environment. Finally the paper draws conclusions about the significance and performance of the proposed gait in terms of tracking errors while navigating in difficult terrains.

Declarative Terrain Modeling for Military Training Games

Directory of Open Access Journals (Sweden)

Ruben M. Smelik

2010-01-01

Full Text Available Military training instructors increasingly often employ computer games to train soldiers in all sorts of skills and tactics. One of the difficulties instructors face when using games as a training tool is the creation of suitable content, including scenarios, entities, and corresponding terrain models. Terrain plays a key role in many military training games, as for example, in our case game Tactical Air Defense. However, current manual terrain editors are both too complex and too time-consuming to be useful for instructors; automatic terrain generation methods show a lot of potential, but still lack user control and intuitive editing capabilities. We present a novel way for instructors to model terrain for their training games: instead of constructing a terrain model using complex modeling tools, instructors can declare the required properties of their terrain using an advanced sketching interface. Our framework integrates terrain generation methods and manages dependencies between terrain features in order to automatically create a complete 3D terrain model that matches the sketch. With our framework, instructors can easily design a large variety of terrain models that meet their training requirements.

Terrain Mapping and Obstacle Detection Using Gaussian Processes

DEFF Research Database (Denmark)

Kjærgaard, Morten; Massaro, Alessandro Salvatore; Bayramoglu, Enis

2011-01-01

In this paper we consider a probabilistic method for extracting terrain maps from a scene and use the information to detect potential navigation obstacles within it. The method uses Gaussian process regression (GPR) to predict an estimate function and its relative uncertainty. To test the new...... show that the estimated maps follow the terrain shape, while protrusions are identified and may be isolated as potential obstacles. Representing the data with a covariance function allows a dramatic reduction of the amount of data to process, while maintaining the statistical properties of the measured...... and interpolated features....

Local curvature entropy-based 3D terrain representation using a comprehensive Quadtree

Science.gov (United States)

Chen, Qiyu; Liu, Gang; Ma, Xiaogang; Mariethoz, Gregoire; He, Zhenwen; Tian, Yiping; Weng, Zhengping

2018-05-01

Large scale 3D digital terrain modeling is a crucial part of many real-time applications in geoinformatics. In recent years, the improved speed and precision in spatial data collection make the original terrain data more complex and bigger, which poses challenges for data management, visualization and analysis. In this work, we presented an effective and comprehensive 3D terrain representation based on local curvature entropy and a dynamic Quadtree. The Level-of-detail (LOD) models of significant terrain features were employed to generate hierarchical terrain surfaces. In order to reduce the radical changes of grid density between adjacent LODs, local entropy of terrain curvature was regarded as a measure of subdividing terrain grid cells. Then, an efficient approach was presented to eliminate the cracks among the different LODs by directly updating the Quadtree due to an edge-based structure proposed in this work. Furthermore, we utilized a threshold of local entropy stored in each parent node of this Quadtree to flexibly control the depth of the Quadtree and dynamically schedule large-scale LOD terrain. Several experiments were implemented to test the performance of the proposed method. The results demonstrate that our method can be applied to construct LOD 3D terrain models with good performance in terms of computational cost and the maintenance of terrain features. Our method has already been deployed in a geographic information system (GIS) for practical uses, and it is able to support the real-time dynamic scheduling of large scale terrain models more easily and efficiently.

AN EXPERIMENTAL EVALUATION OF 3D TERRAIN MAPPING WITH AN AUTONOMOUS HELICOPTER

Directory of Open Access Journals (Sweden)

B. P. Hudzietz

2012-09-01

Full Text Available We demonstrate a method for unmanned aerial vehicle based structure from motion mapping and show it to be a viable option for large scale, high resolution terrain modeling. Current methods of large scale terrain modeling can be cost and time prohibitive. We present a method for integrating low cost cameras and unmanned aerial vehicles for the purpose of 3D terrain mapping. Using structure from motion, aerial images taken of the landscape can be reconstructed into 3D models of the terrain. This process is well suited for use on unmanned aerial vehicles due to the light weight and low cost of equipment. We discuss issues of flight path planning and propose an algorithm to assist in the generation of these paths. The structure from motion mapping process is experimentally evaluated in three distinct environments: ground based testing on man-made environments, ground based testing on natural environments, and airborne testing on natural environments. Ground based testing on natural environments was shown to be extremely useful for camera calibration, and the resulting models were found to have a maximum error of 4.26 cm and standard deviation of 1.50 cm. During airborne testing, several areas of approximately 30,000 m2 were mapped. These areas were mapped with acceptable accuracy and a resolution of 1.24 cm.

Energy management that generates terrain following versus apex-preserving hopping in man and machine.

Science.gov (United States)

Kalveram, Karl Theodor; Haeufle, Daniel F B; Seyfarth, André; Grimmer, Sten

2012-01-01

While hopping, 12 subjects experienced a sudden step down of 5 or 10 cm. Results revealed that the hopping style was "terrain following". It means that the subjects pursued to keep the distance between maximum hopping height (apex) and ground profile constant. The spring-loaded inverse pendulum (SLIP) model, however, which is currently considered as template for stable legged locomotion would predict apex-preserving hopping, by which the absolute maximal hopping height is kept constant regardless of changes of the ground level. To get more insight into the physics of hopping, we outlined two concepts of energy management: "constant energy supply", by which in each bounce--regardless of perturbations--the same amount of mechanical energy is injected, and "lost energy supply", by which the mechanical energy that is going to be dissipated in the current cycle is assessed and replenished. When tested by simulations and on a robot testbed capable of hopping, constant energy supply generated stable and robust terrain following hopping, whereas lost energy supply led to something like apex-preserving hopping, which, however, lacks stability as well as robustness. Comparing simulated and machine hopping with human hopping suggests that constant energy supply has a good chance to be used by humans to generate hopping.

Treinta y Tres stratigraphic terrain: ex Cuchilla Dionisio terrain. Uruguay

International Nuclear Information System (INIS)

Bossi, J.

2010-01-01

From 1998 we are discussing if the eastern area of ZCSB is an allochtonous block named TCD or if it belongs to Dom Feliciano belt with an age of 500 - 700 Ma. This crustal block is difficult to study because Laguna Merin Graben cut it in two around 4000 k m2 crustal fragments distant s more de 100 km between them. Southern block which was named T PE by Masquelín (2006) was demonstrated as allochtonous by Bossi and Gaucher (2004) destroying the Cdf model but seriously complicating the stratigraphic terminology. It is proposed to do some changes in order to profit the general agreement about allochtomy. The CDT with change by Treinta y Tres terrane; T PE become sub - terrain Punta del Este; sub - terrain Cuchilla Dionisio for the septetrional block. From 1998 we are discussing if the eastern area of ZCSB is an allochtonous block named TCD or if it belongs to Dom Feliciano belt with an age of 500 - 700 Ma. This crustal block is difficult to study because Laguna Merín Graben cut it in two around 4000 k m2 crustal fragments distant s more de 100 km between them. Southern block which was named T PE by Masquelín (2006) was demonstrated as allochtonous by Bossi and Gaucher (2004) destroying the CDF model but seriously complicating the stratigraphic terminology. It is proposed to do some changes in order to profit the general agreement about allochtomy. The CDT with change by Treinta y Tres terrain; TPE become sub - terrain Punta del Este; sub - terrain Cuchilla Dionisio for the septetrional block

Terrain assessment guidelines : CAGC best practice. Version 3

Energy Technology Data Exchange (ETDEWEB)

NONE

2009-07-01

This terrain classification assessment guideline discussed the steps required for personnel to understand terrain hazards present during seismic operations. Maps and other sources must be used to classify terrain steepness and surface conditions using geographical information systems (GIS), LIDAR, or satellite photographs. The impact of managing steep terrain within projects must also be considered when class 3, 4, 5, or 6 terrain has been identified. Terrains must also be classified according to colours. Secondary terrain assessments must be conducted when class 3, 4, 5, or 6 terrain has been identified. Terrain management plans should included methods of keeping untrained workers out of areas with classes greater than 3. Methods of entering and exiting steep terrain must be identified. Workers must be trained to work in areas with steep terrains. Methods of rescue and evacuation must also be established. Procedures were outlined for all terrain classes. Footwear, head protection and general safety requirements were outlined. 14 figs.

Irregular Morphing for Real-Time Rendering of Large Terrain

Directory of Open Access Journals (Sweden)

S. Kalem

2016-06-01

Full Text Available The following paper proposes an alternative approach to the real-time adaptive triangulation problem. A new region-based multi-resolution approach for terrain rendering is described which improves on-the-fly the distribution of the density of triangles inside the tile after selecting appropriate Level-Of-Detail by an adaptive sampling. This proposed approach organizes the heightmap into a QuadTree of tiles that are processed independently. This technique combines the benefits of both Triangular Irregular Network approach and region-based multi-resolution approach by improving the distribution of the density of triangles inside the tile. Our technique morphs the initial regular grid of the tile to deformed grid in order to minimize approximation error. The proposed technique strives to combine large tile size and real-time processing while guaranteeing an upper bound on the screen space error. Thus, this approach adapts terrain rendering process to local surface characteristics and enables on-the-fly handling of large amount of terrain data. Morphing is based-on the multi-resolution wavelet analysis. The use of the D2WT multi-resolution analysis of the terrain height-map speeds up processing and permits to satisfy an interactive terrain rendering. Tests and experiments demonstrate that Haar B-Spline wavelet, well known for its properties of localization and its compact support, is suitable for fast and accurate redistribution. Such technique could be exploited in client-server architecture for supporting interactive high-quality remote visualization of very large terrain.

Prediction of wind energy distribution in complex terrain using CFD

DEFF Research Database (Denmark)

Xu, Chang; Li, Chenqi; Yang, Jianchuan

2013-01-01

Based on linear models, WAsP software predicts wind energy distribution, with a good accuracy for flat terrain, but with a large error under complicated topography. In this paper, numerical simulations are carried out using the FLUENT software on a mesh generated by the GAMBIT and ARGIS software ...

An evaluation of WRF's ability to reproduce the surface wind over complex terrain based on typical circulation patterns.

NARCIS (Netherlands)

Jiménez, P.A.; Dudhia, J.; González-Rouco, J.F.; Montávez, J.P.; Garcia-Bustamante, E.; Navarro, J.; Vilà-Guerau de Arellano, J.; Munoz-Roldán, A.

2013-01-01

[1] The performance of the Weather Research and Forecasting (WRF) model to reproduce the surface wind circulations over complex terrain is examined. The atmospheric evolution is simulated using two versions of the WRF model during an over 13¿year period (1992 to 2005) over a complex terrain region

NPSNET: Dynamic Terrain and Cultured Feature Depiction

Science.gov (United States)

1992-09-01

defaults. bridge(terrain *ptr, vertex pos, bridge mattype bmat ); This constructor takes only the pointer to the underlying terrain, a placement, and a...material to use for construction. bridge(terrain *ptr, vertex pos, bridge-mattype bmat , float dir); This constructor takes a terrain pointer, a...placement position, a material to use, and a direction to run. bridge(terrain *ptr, vertex pos, bridge-mattype bmat , float dir, float width, float height

Simulator testing system (STS)

International Nuclear Information System (INIS)

Miller, V.N.

1990-01-01

In recent years there has been a greater demand placed on the capabilities and time usage of real-time nuclear plant simulators due to NRC, INPO and utilities requirements. The requirements applied to certification, new simulators, upgrades, modifications, and maintenance of the simulators vary; however, they all require the capabilities of the simulator to be tested whether it is for NRC 10CFR55.45b requirements, ATP testing of new simulators, ATP testing of upgrades with or without panels, adding software/hardware due to plant modifications, or analyzing software/hardware problems on the simulator. This paper describes the Simulator Testing System (STS) which addresses each one of these requirements placed on simulators. Special attention will be given to ATP testing of upgrades without the use of control room panels. The capabilities and applications of the four parts of STS which are the Display Control Software (DCS), Procedure Control Software (PCS), Display Generator Software (DGS) and the Procedure Generator Software (PGS) will be reviewed

Terrain Mapping and Classification in Outdoor Environments Using Neural Networks

OpenAIRE

Alberto Yukinobu Hata; Denis Fernando Wolf; Gustavo Pessin; Fernando Osório

2009-01-01

This paper describes a three-dimensional terrain mapping and classification technique to allow the operation of mobile robots in outdoor environments using laser range finders. We propose the use of a multi-layer perceptron neural network to classify the terrain into navigable, partially navigable, and non-navigable. The maps generated by our approach can be used for path planning, navigation, and local obstacle avoidance. Experimental tests using an outdoor robot and a laser sensor demonstra...

Lie group model neuromorphic geometric engine for real-time terrain reconstruction from stereoscopic aerial photos

Science.gov (United States)

Tsao, Thomas R.; Tsao, Doris

1997-04-01

In the 1980's, neurobiologist suggested a simple mechanism in primate visual cortex for maintaining a stable and invariant representation of a moving object. The receptive field of visual neurons has real-time transforms in response to motion, to maintain a stable representation. When the visual stimulus is changed due to motion, the geometric transform of the stimulus triggers a dual transform of the receptive field. This dual transform in the receptive fields compensates geometric variation in the stimulus. This process can be modelled using a Lie group method. The massive array of affine parameter sensing circuits will function as a smart sensor tightly coupled to the passive imaging sensor (retina). Neural geometric engine is a neuromorphic computing device simulating our Lie group model of spatial perception of primate's primal visual cortex. We have developed the computer simulation and experimented on realistic and synthetic image data, and performed a preliminary research of using analog VLSI technology for implementation of the neural geometric engine. We have benchmark tested on DMA's terrain data with their result and have built an analog integrated circuit to verify the computational structure of the engine. When fully implemented on ANALOG VLSI chip, we will be able to accurately reconstruct a 3D terrain surface in real-time from stereoscopic imagery.

Object Georeferencing in UAV-Based SAR Terrain Images

Directory of Open Access Journals (Sweden)

Łabowski Michał

2016-12-01

Full Text Available Synthetic aperture radars (SAR allow to obtain high resolution terrain images comparable with the resolution of optical methods. Radar imaging is independent on the weather conditions and the daylight. The process of analysis of the SAR images consists primarily of identifying of interesting objects. The ability to determine their geographical coordinates can increase usability of the solution from a user point of view. The paper presents a georeferencing method of the radar terrain images. The presented images were obtained from the SAR system installed on board an Unmanned Aerial Vehicle (UAV. The system was developed within a project under acronym WATSAR realized by the Military University of Technology and WB Electronics S.A. The source of the navigation data was an INS/GNSS system integrated by the Kalman filter with a feed-backward correction loop. The paper presents the terrain images obtained during flight tests and results of selected objects georeferencing with an assessment of the accuracy of the method.

Parabolic Equation Modeling of Propagation over Terrain Using Digital Elevation Model

Directory of Open Access Journals (Sweden)

Xiao-Wei Guan

2018-01-01

Full Text Available The parabolic equation method based on digital elevation model (DEM is applied on propagation predictions over irregular terrains. Starting from a parabolic approximation to the Helmholtz equation, a wide-angle parabolic equation is deduced under the assumption of forward propagation and the split-step Fourier transform algorithm is used to solve it. The application of DEM is extended to the Cartesian coordinate system and expected to provide a precise representation of a three-dimensional surface with high efficiency. In order to validate the accuracy, a perfectly conducting Gaussian terrain profile is simulated and the results are compared with the shift map. As a consequence, a good agreement is observed. Besides, another example is given to provide a theoretical basis and reference for DEM selection. The simulation results demonstrate that the prediction errors will be obvious only when the resolution of the DEM used is much larger than the range step in the PE method.

A multi-mode real-time terrain parameter estimation method for wheeled motion control of mobile robots

Science.gov (United States)

Li, Yuankai; Ding, Liang; Zheng, Zhizhong; Yang, Qizhi; Zhao, Xingang; Liu, Guangjun

2018-05-01

For motion control of wheeled planetary rovers traversing on deformable terrain, real-time terrain parameter estimation is critical in modeling the wheel-terrain interaction and compensating the effect of wheel slipping. A multi-mode real-time estimation method is proposed in this paper to achieve accurate terrain parameter estimation. The proposed method is composed of an inner layer for real-time filtering and an outer layer for online update. In the inner layer, sinkage exponent and internal frictional angle, which have higher sensitivity than that of the other terrain parameters to wheel-terrain interaction forces, are estimated in real time by using an adaptive robust extended Kalman filter (AREKF), whereas the other parameters are fixed with nominal values. The inner layer result can help synthesize the current wheel-terrain contact forces with adequate precision, but has limited prediction capability for time-variable wheel slipping. To improve estimation accuracy of the result from the inner layer, an outer layer based on recursive Gauss-Newton (RGN) algorithm is introduced to refine the result of real-time filtering according to the innovation contained in the history data. With the two-layer structure, the proposed method can work in three fundamental estimation modes: EKF, REKF and RGN, making the method applicable for flat, rough and non-uniform terrains. Simulations have demonstrated the effectiveness of the proposed method under three terrain types, showing the advantages of introducing the two-layer structure.

Aviation Safety Simulation Model

Science.gov (United States)

Houser, Scott; Yackovetsky, Robert (Technical Monitor)

2001-01-01

The Aviation Safety Simulation Model is a software tool that enables users to configure a terrain, a flight path, and an aircraft and simulate the aircraft's flight along the path. The simulation monitors the aircraft's proximity to terrain obstructions, and reports when the aircraft violates accepted minimum distances from an obstruction. This model design facilitates future enhancements to address other flight safety issues, particularly air and runway traffic scenarios. This report shows the user how to build a simulation scenario and run it. It also explains the model's output.

Effect of an isolated elliptical terrain (Jeju Island on rainfall enhancement in a moist environment

Directory of Open Access Journals (Sweden)

Keun-OK Lee

2014-03-01

Full Text Available A series of idealised experiments using a cloud-resolving storm simulator (CReSS was performed to investigate the effects of the isolated elliptically shaped terrain of Jeju Island (oriented east–west, southern Korea, on the enhancement of pre-existing rainfall systems under the influence of prevailing southwesterly moist flows. Control parameters were the low-altitude wind speed (Froude numbers: 0.2, 0.4, 0.55 and the initial location of the elongated (oriented north–east rainfall system (off the northwestern or western shores of the island. Simulations were conducted for all combinations of initial location and wind regime. Overall, results indicate that weak southwesterlies flowing around the steep mountain on the island (height, 2 km generate two local convergences, on the northern lateral side and on the lee side of the island, both in regions of moist environments, thus producing conditions favourable for enhanced rainfall. As an eastward-moving rainfall system approaches the northwestern shore of the island, the southwesterlies at low altitudes accelerate between the system and the terrain, generating a local updraft region that causes rainfall enhancement onshore in advance of the system's arrival over the terrain. Thus, the prevailing southwesterlies at low altitudes that are parallel to the terrain are a crucial element for the enhancement. Relatively weak southwesterlies at low altitudes allow system enhancement on the lee side by generating a convergence of relatively weak go-around northwesterlies from the northern island and relatively strong moist southwesterlies from the southern island, thus producing a relatively long-lived rainfall system. As the southwesterlies strengthen, a dry descending air mass intensifies on the northeastern downwind side of the terrain, rapidly dissipating rainfall and resulting in a relatively short-lived rainfall system. A coexisting terrain-generated local convergence, combined with the absence

New formulation for interferometric synthetic aperture radar for terrain mapping

Science.gov (United States)

Jakowatz, Charles V., Jr.; Wahl, Daniel E.; Eichel, Paul H.; Thompson, Paul A.

1994-06-01

The subject of interferometric synthetic aperture radar (IFSAR) for high-accuracy terrain elevation mapping continues to gain importance in the arena of radar signal processing. Applications to problems in precision terrain-aided guidance and automatic target recognition, as well as a variety of civil applications, are being studied by a number of researchers. Not unlike many other areas of SAR processing, the subject of IFSAR can, at first glance, appear to be somewhat mysterious. In this paper we show how the mathematics of IFSAR for terrain elevation mapping using a pair of spotlight mode SAR collections can be derived in a very straightforward manner. Here, we employ an approach that relies entirely on Fourier transforms, and utilizes no reference to range equations or Doppler concepts. The result is a simplified explanation of the fundamentals of interferometry, including an easily-seen link between image domain phase difference and terrain elevation height. The derivation builds upon previous work by the authors in which a framework for spotlight mode SAR image formation based on an analogy to 3D computerized axial tomography (CAT) was developed. After outlining the major steps in the mathematics, we show how a computer simulator which utilizes 3D Fourier transforms can be constructed that demonstrates all of the major aspects of IFSAR from spotlight mode collections.

Processing Terrain Point Cloud Data

KAUST Repository

DeVore, Ronald

2013-01-10

Terrain point cloud data are typically acquired through some form of Light Detection And Ranging sensing. They form a rich resource that is important in a variety of applications including navigation, line of sight, and terrain visualization. Processing terrain data has not received the attention of other forms of surface reconstruction or of image processing. The goal of terrain data processing is to convert the point cloud into a succinct representation system that is amenable to the various application demands. The present paper presents a platform for terrain processing built on the following principles: (i) measuring distortion in the Hausdorff metric, which we argue is a good match for the application demands, (ii) a multiscale representation based on tree approximation using local polynomial fitting. The basic elements held in the nodes of the tree can be efficiently encoded, transmitted, visualized, and utilized for the various target applications. Several challenges emerge because of the variable resolution of the data, missing data, occlusions, and noise. Techniques for identifying and handling these challenges are developed. © 2013 Society for Industrial and Applied Mathematics.

Wind farm layout optimization in complex terrain: A preliminary study on a Gaussian hill

International Nuclear Information System (INIS)

Feng, J; Shen, W Z

2014-01-01

One of the crucial problems for wind farm (WF) development is wind farm layout optimization. It seeks to find the optimal positions of wind turbines (WTs) inside a WF, so as to maximize and/or minimize a single objective or multiple objectives, while satisfying certain constraints. Although this problem for WFs in flat terrain or offshore has been investigated in many studies, it is still a challenging problem for WFs in complex terrain. In this preliminary study, the wind flow conditions of complex terrain without WTs are first obtained from computational fluid dynamics (CFD) simulation, then an adapted Jensen wake model is developed by considering the terrain features and taking the inflow conditions as input. Using this combined method, the wake effects of WF in complex terrain are properly modelled. Besides, a random search (RS) algorithm proposed in previous study is improved by adding some adaptive mechanisms and applied to solve the layout optimization problem of a WF on a Gaussian shape hill. The layout of the WF with a certain number of WTs is optimized to maximize the total power output, which obtained steady improvements over expert guess layouts

Processing Terrain Point Cloud Data

KAUST Repository

DeVore, Ronald; Petrova, Guergana; Hielsberg, Matthew; Owens, Luke; Clack, Billy; Sood, Alok

2013-01-01

Terrain point cloud data are typically acquired through some form of Light Detection And Ranging sensing. They form a rich resource that is important in a variety of applications including navigation, line of sight, and terrain visualization

Large-eddy simulation of atmospheric flow over complex terrain

Energy Technology Data Exchange (ETDEWEB)

Bechmann, A.

2006-11-15

The present report describes the development and validation of a turbulence model designed for atmospheric flows based on the concept of Large-Eddy Simulation (LES). The background for the work is the high Reynolds number k - epsilon model, which has been implemented on a finite-volume code of the incompressible Reynolds-averaged Navier-Stokes equations (RANS). The k - epsilon model is traditionally used for RANS computations, but is here developed to also enable LES. LES is able to provide detailed descriptions of a wide range of engineering flows at low Reynolds numbers. For atmospheric flows, however, the high Reynolds numbers and the rough surface of the earth provide difficulties normally not compatible with LES. Since these issues are most severe near the surface they are addressed by handling the near surface region with RANS and only use LES above this region. Using this method, the developed turbulence model is able to handle both engineering and atmospheric flows and can be run in both RANS or LES mode. For LES simulations a time-dependent wind field that accurately represents the turbulent structures of a wind environment must be prescribed at the computational inlet. A method is implemented where the turbulent wind field from a separate LES simulation can be used as inflow. To avoid numerical dissipation of turbulence special care is paid to the numerical method, e.g. the turbulence model is calibrated with the specific numerical scheme used. This is done by simulating decaying isotropic and homogeneous turbulence. Three atmospheric test cases are investigated in order to validate the behavior of the presented turbulence model. Simulation of the neutral atmospheric boundary layer, illustrates the turbulence model ability to generate and maintain the turbulent structures responsible for boundary layer transport processes. Velocity and turbulence profiles are in good agreement with measurements. Simulation of the flow over the Askervein hill is also

Repository simulation tests

International Nuclear Information System (INIS)

Wicks, G.G.; Bibler, N.E.; Jantzen, C.M.; Plodinec, M.J.

1984-01-01

The repository simulation experiments described in this paper are designed to assess the performance of SRP waste glass under the most realistic repository conditions that can be obtained in the laboratory. These tests simulate the repository environment as closely as possible and introduce systematically the variability of the geology, groundwater chemistry, and waste package components during the leaching of the waste glass. The tests evaluate waste form performance under site-specific conditions, which differ for each of the geologic repositories under consideration. Data from these experiments will aid in the development of a realistic source term that can describe the release of radionuclides from SRP waste glass as a component of proposed waste packages. Hence, this information can be useful to optimize waste package design for SRP waste glass and to provide data for predicting long-term performance and subsequent conformance to regulations. The repository simulation tests also help to bridge the gap in interpreting results derived from tests performed under the control of the laboratory to the uncertainity and variability of field tests. In these experiments, site-specific repository components and conditions are emphasized and only the site specific materials contact the waste forms. An important feature of these tests is that both actual and simulated waste glasses are tested identically. 7 figures, 2 tables

Experimental and Numerical Modelling of Flow over Complex Terrain: The Bolund Hill

Science.gov (United States)

Conan, Boris; Chaudhari, Ashvinkumar; Aubrun, Sandrine; van Beeck, Jeroen; Hämäläinen, Jari; Hellsten, Antti

2016-02-01

In the wind-energy sector, wind-power forecasting, turbine siting, and turbine-design selection are all highly dependent on a precise evaluation of atmospheric wind conditions. On-site measurements provide reliable data; however, in complex terrain and at the scale of a wind farm, local measurements may be insufficient for a detailed site description. On highly variable terrain, numerical models are commonly used but still constitute a challenge regarding simulation and interpretation. We propose a joint state-of-the-art study of two approaches to modelling atmospheric flow over the Bolund hill: a wind-tunnel test and a large-eddy simulation (LES). The approach has the particularity of describing both methods in parallel in order to highlight their similarities and differences. The work provides a first detailed comparison between field measurements, wind-tunnel experiments and numerical simulations. The systematic and quantitative approach used for the comparison contributes to a better understanding of the strengths and weaknesses of each model and, therefore, to their enhancement. Despite fundamental modelling differences, both techniques result in only a 5 % difference in the mean wind speed and 15 % in the turbulent kinetic energy (TKE). The joint comparison makes it possible to identify the most difficult features to model: the near-ground flow and the wake of the hill. When compared to field data, both models reach 11 % error for the mean wind speed, which is close to the best performance reported in the literature. For the TKE, a great improvement is found using the LES model compared to previous studies (20 % error). Wind-tunnel results are in the low range of error when compared to experiments reported previously (40 % error). This comparison highlights the potential of such approaches and gives directions for the improvement of complex flow modelling.

Techniques for Automatic Creation of Terrain Databases for Training and Mission Preparation

NARCIS (Netherlands)

Kuijper, F.; Son, R. van; Meurs, F. van; Smelik, R.M.; Kraker, J.K. de

2010-01-01

In the support of defense agencies and civil authorities TNO runs a research program that strives after automatic generation of terrain databases for a variety of simulation applications. Earlier papers by TNO at the IMAGE conference have reported in-depth on specific projects within this program.

Survivor shielding. Part C. Improvements in terrain shielding

International Nuclear Information System (INIS)

Egbert, Stephen D.; Kaul, Dean C.; Roberts, James A.; Kerr, George D.

2005-01-01

A number of atomic-bomb survivors were affected by shielding provided by terrain features. These terrain features can be a small hill, affecting one or two houses, or a high mountain that shields large neighborhoods. In the survivor dosimetry system, terrain shielding can be described by a transmission factor (TF), which is the ratio between the dose with and without the terrain present. The terrain TF typically ranges between 0.1 and 1.0. After DS86 was implemented at RERF, the terrain shielding categories were examined and found to either have a bias or an excessive uncertainty that could readily be removed. In 1989, an improvement in the terrain model was implemented at RERF in the revised DS86 code, but the documentation was not published. It is now presented in this section. The solution to the terrain shielding in front of a house is described in this section. The problem of terrain shielding of survivors behind Hijiyama mountain at Hiroshima and Konpirasan mountain at Nagasaki has also been recognized, and a solution to this problem has been included in DS02. (author)

Scout Rover Applications for Forward Acquisition of Soil and Terrain Data

Science.gov (United States)

Sonsalla, R.; Ahmed, M.; Fritsche, M.; Akpo, J.; Voegele, T.

2014-04-01

As opposed to the present mars exploration missions future mission concepts ask for a fast and safe traverse through vast and varied expanses of terrain. As seen during the Mars Exploration Rover (MER) mission the rovers suffered a lack of detailed soil and terrain information which caused Spirit to get permanently stuck in soft soil. The goal of the FASTER1 EU-FP7 project is to improve the mission safety and the effective traverse speed for planetary rover exploration by determining the traversability of the terrain and lowering the risk to enter hazardous areas. To achieve these goals, a scout rover will be used for soil and terrain sensing ahead of the main rover. This paper describes a highly mobile, and versatile micro scout rover that is used for soil and terrain sensing and is able to co-operate with a primary rover as part of the FASTER approach. The general reference mission idea and concept is addressed within this paper along with top-level requirements derived from the proposed ESA/NASA Mars Sample Return mission (MSR) [4]. Following the mission concept and requirements [3], a concept study for scout rover design and operations has been performed [5]. Based on this study the baseline for the Coyote II rover was designed and built as shown in Figure 1. Coyote II is equipped with a novel locomotion concept, providing high all terrain mobility and allowing to perform side-to-side steering maneuvers which reduce the soil disturbance as compared to common skid steering [6]. The rover serves as test platform for various scout rover application tests ranging from locomotion testing to dual rover operations. From the lessons learned from Coyote II and for an enhanced design, a second generation rover (namely Coyote III) as shown in Figure 2 is being built. This rover serves as scout rover platform for the envisaged FASTER proof of concept field trials. The rover design is based on the test results gained by the Coyote II trials. Coyote III is equipped with two

Morphological modeling of terrains and volume data

CERN Document Server

Comic, Lidija; Magillo, Paola; Iuricich, Federico

2014-01-01

This book describes the mathematical background behind discrete approaches to morphological analysis of scalar fields, with a focus on Morse theory and on the discrete theories due to Banchoff and Forman. The algorithms and data structures presented are used for terrain modeling and analysis, molecular shape analysis, and for analysis or visualization of sensor and simulation 3D data sets. It covers a variety of application domains including geography, geology, environmental sciences, medicine and biology. The authors classify the different approaches to morphological analysis which are all ba

Effect of load carriage and natural terrain conditions on cognitive performance in desert environments.

Science.gov (United States)

Bhattacharyya, Debojyoti; Pal, Madhusudan; Chatterjee, Tirthankar; Majumdar, Dhurjati

2017-10-01

Correct decision making is a critical component of cognitive performance of a soldier, which may be influenced by the load carriage and terrain conditions during their deployment in desert environment. The present study was aimed to investigate the effects of loads and terrain conditions on the cognitive performance in a group of twelve healthy heat acclimatized infantry soldiers under natural desert environment. The soldiers participated in a 10min walking trial during carrying no load and also carrying 10.7, 21.4 and 30kg at two terrain conditions viz., sandy and hard. We studied attention, memory and executive function, which are having immense functional importance in military operations. Standardized cognitive test battery was applied to the participants after carrying each magnitude of load at each terrain. Baseline cognitive performance was recorded on a separate day and was compared with the performances recorded after the load carriage trials. An attempt was made to reveal the relationship between physiological workload (relative workload) and cognitive performance at the point of completion of load carriage trials. Load, terrains and load×terrain interaction did not produce any significant effect (p>0.05) on the cognitive performance. Attention and relative workload were found significantly correlated at hard terrain under no load, 21.4kg and 30kg. Significant correlation was found between executive function and relative workload at hard terrain under no load. Carrying upto 30kg load for 10min at 3.5-4kmph walking speed resulted in improvement in attention at sandy terrain, decrement in memory at both sandy and hard terrains and improvement in executive function at sandy terrain. Copyright © 2017 Elsevier Inc. All rights reserved.

Simulation of wind-induced snow transport and sublimation in alpine terrain using a fully coupled snowpack/atmosphere model

Science.gov (United States)

Vionnet, V.; Martin, E.; Masson, V.; Guyomarc'h, G.; Naaim-Bouvet, F.; Prokop, A.; Durand, Y.; Lac, C.

2014-03-01

In alpine regions, wind-induced snow transport strongly influences the spatio-temporal evolution of the snow cover throughout the winter season. To gain understanding on the complex processes that drive the redistribution of snow, a new numerical model is developed. It directly couples the detailed snowpack model Crocus with the atmospheric model Meso-NH. Meso-NH/Crocus simulates snow transport in saltation and in turbulent suspension and includes the sublimation of suspended snow particles. The coupled model is evaluated against data collected around the experimental site of Col du Lac Blanc (2720 m a.s.l., French Alps). First, 1-D simulations show that a detailed representation of the first metres of the atmosphere is required to reproduce strong gradients of blowing snow concentration and compute mass exchange between the snowpack and the atmosphere. Secondly, 3-D simulations of a blowing snow event without concurrent snowfall have been carried out. Results show that the model captures the main structures of atmospheric flow in alpine terrain. However, at 50 m grid spacing, the model reproduces only the patterns of snow erosion and deposition at the ridge scale and misses smaller scale patterns observed by terrestrial laser scanning. When activated, the sublimation of suspended snow particles causes a reduction of deposited snow mass of 5.3% over the calculation domain. Total sublimation (surface + blowing snow) is three times higher than surface sublimation in a simulation neglecting blowing snow sublimation.

Terrain reconstruction based on descent images for the Chang’e III landing area

Directory of Open Access Journals (Sweden)

Xu Xinchao

2015-10-01

Full Text Available A new method that combined image matching and shape from shading for terrain reconstruction was proposed to solve the lack of terrain in the landing area of Chang'e III. First, the reflection equation was established based on the Lommel– Seeliger reflection model. After edge extraction, the gradients of points on the edge were solved. The normal vectors of adjacent points were obtained using the smoothness constraint. Furthermore, the gradients of residual points in the image were determined through evolution. The inadequacy of the reflection equation was eliminated by considering the gradient as the constraint of the reflection equation. The normal vector of each point could be obtained by solving the reflection equation. The terrain without coordinate information was reconstructed by iterating the vector field. After using scaleinvariant feature transform to extract matching points in the descent images, the terrain was converted to a lander centroid coordinate system. Experiments were carried out with MATLAB-simulated images, laboratory images, and descent images of Chang'e III. Results show that the proposed method performs better than the classical SFS algorithm. The new method can provide reference for other deep space exploration activities.

Spectra of Velocity components over Complex Terrain

DEFF Research Database (Denmark)

Panofsky, H. A.; Larko, D.; Lipschut, R.

1982-01-01

: When air moves over terrain with changed characteristics, then (1) for wavelengths very short relative to the fetch over the new terrain, the spectral densities are in equilibrium with the new terrain. (1) for wavelengths long compared to this fetch, spectral densities remain unchanged if the ground...

Rough terrain motion planning for actively reconfigurable mobile robots

International Nuclear Information System (INIS)

Brunner, Michael

2015-01-01

In the aftermath of the Tohoku earthquake and the nuclear meltdown at the power plant of Fukushima Daiichi in 2011, reconfigurable robots like the iRobot Packbot were deployed. Instead of humans, the robots were used to investigate contaminated areas. Other incidents are the two major earthquakes in Northern Italy in May 2012. Besides many casualties, a large number of historical buildings was severely damaged. Due to the imminent danger of collapse, it was too dangerous for rescue personnel to enter many of the buildings. Therefore, the sites were inspected by reconfigurable robots, which are able to traverse the rubble and debris of the partially destroyed buildings. This thesis develops a navigation system enabling wheeled and tracked robots to safely traverse rough terrain and challenging structures. It consists of a planning mechanism and a controller. The focus of this thesis, however, is on the contribution to motion planning. The planning scheme employs a hierarchical approach to motion planning for actively reconfigurable robots in rough environments. Using a map of the environment the algorithm estimates the traversability under the consideration of uncertainties. Based on this analysis, an initial path search determines an approximate solution with respect to the robot's operating limits.Subsequently, a detailed planning step refines the initial path where it is required. The refinement step considers the robot's actuators and stability in addition to the quantities of the first search. Determining the robot-terrain interaction is very important in rough terrain. This thesis presents two path refinement approaches: a deterministic and a randomized approach. The experimental evaluation investigates the separate components of the planning scheme, the robot-terrain interaction for instance.In simulation as well as in real world experiments the evaluation demonstrates the necessity of such a planning algorithm in rough terrain and it provides

Rough terrain motion planning for actively reconfigurable mobile robots

Energy Technology Data Exchange (ETDEWEB)

Brunner, Michael

2015-02-05

In the aftermath of the Tohoku earthquake and the nuclear meltdown at the power plant of Fukushima Daiichi in 2011, reconfigurable robots like the iRobot Packbot were deployed. Instead of humans, the robots were used to investigate contaminated areas. Other incidents are the two major earthquakes in Northern Italy in May 2012. Besides many casualties, a large number of historical buildings was severely damaged. Due to the imminent danger of collapse, it was too dangerous for rescue personnel to enter many of the buildings. Therefore, the sites were inspected by reconfigurable robots, which are able to traverse the rubble and debris of the partially destroyed buildings. This thesis develops a navigation system enabling wheeled and tracked robots to safely traverse rough terrain and challenging structures. It consists of a planning mechanism and a controller. The focus of this thesis, however, is on the contribution to motion planning. The planning scheme employs a hierarchical approach to motion planning for actively reconfigurable robots in rough environments. Using a map of the environment the algorithm estimates the traversability under the consideration of uncertainties. Based on this analysis, an initial path search determines an approximate solution with respect to the robot's operating limits.Subsequently, a detailed planning step refines the initial path where it is required. The refinement step considers the robot's actuators and stability in addition to the quantities of the first search. Determining the robot-terrain interaction is very important in rough terrain. This thesis presents two path refinement approaches: a deterministic and a randomized approach. The experimental evaluation investigates the separate components of the planning scheme, the robot-terrain interaction for instance.In simulation as well as in real world experiments the evaluation demonstrates the necessity of such a planning algorithm in rough terrain and it provides

Evaluation of terrain geomorphometric characteristics for ground clearance charts production

Directory of Open Access Journals (Sweden)

Mirko A. Borisov

2011-01-01

Full Text Available Geomorphometric exploration applied in the military terrain analysis is based on the GIS methodology of spatial analyses and is related primarily to military terrain analyses. It includes relief assessment aiming at producing ground clearance charts for the analysis of terrain maneuverability and its deployment, cover and concealment possibilities. An evaluation analysis of geomorphological parameters was performed for the Avala test area using a few terrain parameters (visibility, terrain aspect and slope as well as some terrain qualitative categories (e.g. vegetation density. Terrain slope Slope and aspect are morphometric terrain parameters that can be derived directly from the DTM using some GIS operations. Slope is the first derivative of a surface and has both magnitude and direction. Slope is perhaps the most important aspect of the surface form, since surfaces are formed completely of slopes, and slope angles control the gravitational force available for geomorphic work. Mathematically, the tangent of the slope angle is the first derivative of altitude, and it is a tangent or percent slope as this surface parameter is generally referred to. Slope is defined at each point as the slope of a plane tangent to the surface at that point. In practice, however, slope is generally measured over a finite distance, especially when data are obtained from a contour map. Terrain aspect Aspect is also the first derivative of a surface and has both magnitude and direction. The term aspect is defined as the direction of the biggest slope vector on the tangent plane projected onto the horizontal plane. Aspect is the bearing (or azimuth of the slope direction, and its angle ranges from 0 to 360°. Analyses of terrain slope and ground clearance for military forces The analysis of land assessment of the Avala test area included the definition of relief categories in relation to cover and concealment purposes with the aim to include the geomorphological basis

ISOSTATICALLY DISTURBED TERRAIN OF NORTHWESTERN ANDES MOUNTAINS FROM SPECTRALLY CORRELATED FREE-AIR AND GRAVITY TERRAIN DATA

Directory of Open Access Journals (Sweden)

Hernández P Orlando

2006-12-01

Full Text Available Recently revised models on global tectonics describe the convergence of the North Andes, Nazca, Caribbean and South American Plates and their seismicity, volcanism, active faulting and extreme
topography. The current plate boundaries of the area are mainly interpreted from volcanic and seismic datasets with variable confidence levels. New insights on the isostatic state and plate boundaries of
the northwestern Andes Mountains can be obtained from the spectral analysis of recently available gravity and topography data.
Isostatically disturbed terrain produces free-air anomalies that are highly correlated with the gravity effects of the terrain. The terrain gravity effects (TGE and free air gravity anomalies (FAGA of the
Andes mountains spectral correlation data confirms that these mountains are isostatically disturbed. Strong negative terrain-correlated FAGA along western South America and the Greater and Lesser Antilles are consistent with anomalously deepened mantle displaced by subducting oceanic plates.

Inversion of the compensated terrain gravity effects (CTGE reveals plate subduction systems with alternating shallower and steeper subduction angles. The gravity modeling highlights crustal
deformation from plate collision and subduction and other constraints on the tectonism of the plate boundary zones for the region.

Path Planning and Replanning for Mobile Robot Navigation on 3D Terrain: An Approach Based on Geodesic

Directory of Open Access Journals (Sweden)

Kun-Lin Wu

2016-01-01

Full Text Available In this paper, mobile robot navigation on a 3D terrain with a single obstacle is addressed. The terrain is modelled as a smooth, complete manifold with well-defined tangent planes and the hazardous region is modelled as an enclosing circle with a hazard grade tuned radius representing the obstacle projected onto the terrain to allow efficient path-obstacle intersection checking. To resolve the intersections along the initial geodesic, by resorting to the geodesic ideas from differential geometry on surfaces and manifolds, we present a geodesic-based planning and replanning algorithm as a new method for obstacle avoidance on a 3D terrain without using boundary following on the obstacle surface. The replanning algorithm generates two new paths, each a composition of two geodesics, connected via critical points whose locations are found to be heavily relying on the exploration of the terrain via directional scanning on the tangent plane at the first intersection point of the initial geodesic with the circle. An advantage of this geodesic path replanning procedure is that traversability of terrain on which the detour path traverses could be explored based on the local Gauss-Bonnet Theorem of the geodesic triangle at the planning stage. A simulation demonstrates the practicality of the analytical geodesic replanning procedure for navigating a constant speed point robot on a 3D hill-like terrain.

A Multi-Scale Validation Strategy for Albedo Products over Rugged Terrain and Preliminary Application in Heihe River Basin, China

Directory of Open Access Journals (Sweden)

Xingwen Lin

2018-01-01

Full Text Available The issue for the validation of land surface remote sensing albedo products over rugged terrain is the scale effects between the reference albedo measurements and coarse scale albedo products, which is caused by the complex topography. This paper illustrates a multi-scale validation strategy specified for coarse scale albedo validation over rugged terrain. A Mountain-Radiation-Transfer-based (MRT-based albedo upscaling model was proposed in the process of multi-scale validation strategy for aggregating fine scale albedo to coarse scale. The simulated data of both the reference coarse scale albedo and fine scale albedo were used to assess the performance and uncertainties of the MRT-based albedo upscaling model. The results showed that the MRT-based model could reflect the albedo scale effects over rugged terrain and provided a robust solution for albedo upscaling from fine scale to coarse scale with different mean slopes and different solar zenith angles. The upscaled coarse scale albedos had the great agreements with the simulated coarse scale albedo with a Root-Mean-Square-Error (RMSE of 0.0029 and 0.0017 for black sky albedo (BSA and white sky albedo (WSA, respectively. Then the MRT-based model was preliminarily applied for the assessment of daily MODerate Resolution Imaging Spectroradiometer (MODIS Albedo Collection V006 products (MCD43A3 C6 over rugged terrain. Results showed that the MRT-based model was effective and suitable for conducting the validation of MODIS albedo products over rugged terrain. In this research area, it was shown that the MCD43A3 C6 products with full inversion algorithm, were generally in agreement with the aggregated coarse scale reference albedos over rugged terrain in the Heihe River Basin, with the BSA RMSE of 0.0305 and WSA RMSE of 0.0321, respectively, which were slightly higher than those over flat terrain.

Simulator for materials testing reactors

International Nuclear Information System (INIS)

Takemoto, Noriyuki; Sugaya, Naoto; Ohtsuka, Kaoru; Hanakawa, Hiroki; Onuma, Yuichi; Hosokawa, Jinsaku; Hori, Naohiko; Kaminaga, Masanori; Tamura, Kazuo; Hotta, Kohji; Ishitsuka, Tatsuo

2013-06-01

A real-time simulator for both reactor and irradiation facilities of a materials testing reactor, “Simulator of Materials Testing Reactors”, was developed for understanding reactor behavior and operational training in order to utilize it for nuclear human resource development and to promote partnership with developing countries which have a plan to introduce nuclear power plant. The simulator is designed based on the JMTR (Japan Materials Testing Reactor), and it simulates operation, irradiation tests and various kinds of anticipated operational transients and accident conditions caused by the reactor and irradiation facilities. The development of the simulator was sponsored by the Japanese government as one of the specialized projects of advanced research infrastructure in order to promote basic as well as applied researches. This report summarizes the simulation components, hardware specification and operation procedure of the simulator. (author)

THE DISTRIBUTION MODELING OF IMPURITIES IN THE ATMOSPHERE WITH TAKING INTO ACCOUNT OF TERRAIN

Directory of Open Access Journals (Sweden)

P. B. Mashyhina

2009-03-01

Full Text Available The 2D numerical model to simulate the pollutant dispersion over complex terrain was proposed. The model is based on the equation of potential flow and the equation of admixture transfer. Results of the numerical experiment are presented.

Planning Routes Across Economic Terrains: Maximizing Utility, Following Heuristics

Science.gov (United States)

Zhang, Hang; Maddula, Soumya V.; Maloney, Laurence T.

2010-01-01

We designed an economic task to investigate human planning of routes in landscapes where travel in different kinds of terrain incurs different costs. Participants moved their finger across a touch screen from a starting point to a destination. The screen was divided into distinct kinds of terrain and travel within each kind of terrain imposed a cost proportional to distance traveled. We varied costs and spatial configurations of terrains and participants received fixed bonuses minus the total cost of the routes they chose. We first compared performance to a model maximizing gain. All but one of 12 participants failed to adopt least-cost routes and their failure to do so reduced their winnings by about 30% (median value). We tested in detail whether participants’ choices of routes satisfied three necessary conditions (heuristics) for a route to maximize gain. We report failures of one heuristic for 7 out of 12 participants. Last of all, we modeled human performance with the assumption that participants assign subjective utilities to costs and maximize utility. For 7 out 12 participants, the fitted utility function was an accelerating power function of actual cost and for the remaining 5, a decelerating power function. We discuss connections between utility aggregation in route planning and decision under risk. Our task could be adapted to investigate human strategy and optimality of route planning in full-scale landscapes. PMID:21833269

PLANNING ROUTES ACROSS ECONOMIC TERRAINS: MAXIMIZING UTILITY, FOLLOWING HEURISTICS

Directory of Open Access Journals (Sweden)

Hang eZhang

2010-12-01

Full Text Available We designed an economic task to investigate human planning of routes in landscapes where travel in different kinds of terrain incurs different costs. Participants moved their finger across a touch screen from a starting point to a destination. The screen was divided into distinct kinds of terrain and travel within each kind of terrain imposed a cost proportional to distance traveled. We varied costs and spatial configurations of terrains and participants received fixed bonuses minus the total cost of the routes they chose. We first compared performance to a model maximizing gain. All but one of 12 participants failed to adopt least-cost routes and their failure to do so reduced their winnings by about 30% (median value. We tested in detail whether participants’ choices of routes satisfied three necessary conditions (heuristics for a route to maximize gain. We report failures of one heuristic for 7 out of 12 participants. Last of all, we modeled human performance with the assumption that participants assign subjective utilities to costs and maximize utility. For 7 out 12 participants, the fitted utility function was an accelerating power function of actual cost and for the remaining 5, a decelerating power function. We discuss connections between utility aggregation in route planning and decision under risk. Our task could be adapted to investigate human strategy and optimality of route planning in full-scale landscapes.

Global terrain classification using Multiple-Error-Removed Improved-Terrain (MERIT) to address susceptibility of landslides and other geohazards

Science.gov (United States)

Iwahashi, J.; Yamazaki, D.; Matsuoka, M.; Thamarux, P.; Herrick, J.; Yong, A.; Mital, U.

2017-12-01

A seamless model of landform classifications with regional accuracy will be a powerful platform for geophysical studies that forecast geologic hazards. Spatial variability as a function of landform on a global scale was captured in the automated classifications of Iwahashi and Pike (2007) and additional developments are presented here that incorporate more accurate depictions using higher-resolution elevation data than the original 1-km scale Shuttle Radar Topography Mission digital elevation model (DEM). We create polygon-based terrain classifications globally by using the 280-m DEM interpolated from the Multi-Error-Removed Improved-Terrain DEM (MERIT; Yamazaki et al., 2017). The multi-scale pixel-image analysis method, known as Multi-resolution Segmentation (Baatz and Schäpe, 2000), is first used to classify the terrains based on geometric signatures (slope and local convexity) calculated from the 280-m DEM. Next, we apply the machine learning method of "k-means clustering" to prepare the polygon-based classification at the globe-scale using slope, local convexity and surface texture. We then group the divisions with similar properties by hierarchical clustering and other statistical analyses using geological and geomorphological data of the area where landslides and earthquakes are frequent (e.g. Japan and California). We find the 280-m DEM resolution is only partially sufficient for classifying plains. We nevertheless observe that the categories correspond to reported landslide and liquefaction features at the global scale, suggesting that our model is an appropriate platform to forecast ground failure. To predict seismic amplification, we estimate site conditions using the time-averaged shear-wave velocity in the upper 30-m (VS30) measurements compiled by Yong et al. (2016) and the terrain model developed by Yong (2016; Y16). We plan to test our method on finer resolution DEMs and report our findings to obtain a more globally consistent terrain model as there

Terrain Perception in a Shape Shifting Rolling-Crawling Robot

Directory of Open Access Journals (Sweden)

Fuchida Masataka

2016-09-01

Full Text Available Terrain perception greatly enhances the performance of robots, providing them with essential information on the nature of terrain being traversed. Several living beings in nature offer interesting inspirations which adopt different gait patterns according to nature of terrain. In this paper, we present a novel terrain perception system for our bioinspired robot, Scorpio, to classify the terrain based on visual features and autonomously choose appropriate locomotion mode. Our Scorpio robot is capable of crawling and rolling locomotion modes, mimicking Cebrenus Rechenburgi, a member of the huntsman spider family. Our terrain perception system uses Speeded Up Robust Feature (SURF description method along with color information. Feature extraction is followed by Bag of Word method (BoW and Support Vector Machine (SVM for terrain classification. Experiments were conducted with our Scorpio robot to establish the efficacy and validity of the proposed approach. In our experiments, we achieved a recognition accuracy of over 90% across four terrain types namely grass, gravel, wooden deck, and concrete.

ARAC terrain data base

International Nuclear Information System (INIS)

Walker, H.

1982-11-01

A terrain data base covering the continental United States at 500-meter resolution has been generated. Its function is to provide terrain data for input to mesoscale atmospheric models that are used as part of the Atmospheric Release Advisory Capability at Lawrence Livermore Laboratory (LLNL). The structure of the data base as it exists on the LLNL computer system is described. The data base has been written to tapes for transfer to other systems and the format of these tapes is also described

3D Finite Element Analysis of PWA-Oil Sand Terrain System Interaction

Directory of Open Access Journals (Sweden)

Y. Li

2012-01-01

Full Text Available A simulator for analyzing the interaction between the oil sand terrain and a pipe wagon articulating (PWA system has been developed in this paper. An elastic-plastic oil sand model was built based on the finite element analysis (FEA method and von Mises yield criterion using the Algor mechanical event simulation (MES software. The three-dimensional (3D distribution of the stress, strain, nodal displacement, and deformed shape of the oil sands was animated at an environmental temperature of 25°C. The 3D behavior of the oil sand terrain was investigated with different loading conditions. The effect of the load and contact area on the stress and nodal displacement was analyzed, respectively. The results indicate that both the max stress and max nodal displacement increase with the load varying from 0 to 3.6+7 N and decrease with the contact area varying from 2 to 10 m2. The method presented in this paper forms the basis for evaluating the bearing capacity of oil sand ground.

Hybrid RANS/LES method for wind flow over complex terrain

DEFF Research Database (Denmark)

Bechmann, Andreas; Sørensen, Niels N.

2010-01-01

for flows at high Reynolds numbers. To reduce the computational cost of traditional LES, a hybrid method is proposed in which the near-wall eddies are modelled in a Reynolds-averaged sense. Close to walls, the flow is treated with the Reynolds-averaged Navier-Stokes (RANS) equations (unsteady RANS...... rough walls. Previous attempts of combining RANS and LES has resulted in unphysical transition regions between the two layers, but the present work improves this region by using a stochastic backscatter model. To demonstrate the ability of the proposed hybrid method, simulations are presented for wind...... the turbulent kinetic energy, whereas the new method captures the high turbulence levels well but underestimates the mean velocity. The presented results are for a relative mild configuration of complex terrain, but the proposed method can also be used for highly complex terrain where the benefits of the new...

Toroidal simulation magnet tests

International Nuclear Information System (INIS)

Walstrom, P.L.; Domm, T.C.

1975-01-01

A number of different schemes for testing superconducting coils in a simulated tokamak environment are analyzed for their merits relative to a set of test criteria. Two of the concepts are examined in more detail: the so-called cluster test scheme, which employs two large background field coils, one on either side of the test coil, and the compact torus, a low-aspect ratio toroidal array of a small number of coils in which all of the coils are essentially test coils. Simulation of the pulsed fields of the tokamak is discussed briefly

A method for separation of the terrain and non-terrain from Vehicle-borne Laser Scanning Data

International Nuclear Information System (INIS)

Wei, Jiangxia; Zhong, Ruofei

2014-01-01

Half the points from vehicle-borne laser scanning data are terrain data. If you want to extract features such as trees, street lights and buildings, terrain points must be removed. Nowadays, either airborne or vehicle-borne laser data, are mostly used to set an elevation threshold based on the scanning line or POS data to determine whether the point is a terrain point or not, but the disadvantage is part of low buildings or other feature objects will be lost. If the study area has high differences in the horizontal or the forward direction, this method is not applicable. This paper investigates a new methodology to extract the terrain points, which has great significance for data reduction and classification. The procedure includes the following steps: 1)Pre-processing: to remove discrete points and abnormal points. 2) Divided all the points into grid, calculating the average value of the XY and the minimum value of the Z of all the points in the same grid as the central point of the grid.3) Choose nearest six points which are close to the centre point to fitting the quadratic surface.4)Compare the normal vector of the fitting surface of the grid to the normal vector of the 8-neighborhood, if the difference is too big, it will be smoothed.5) Determine whether the point in the grid is on the surface, if the point belongs to the surface, it will be classified as terrain point. The results and evaluation have shown the effectiveness of the method and its potential in separation of the terrain of various areas

UAS applications in high alpine, snow-covered terrain

Science.gov (United States)

Bühler, Y.; Stoffel, A.; Ginzler, C.

2017-12-01

Access to snow-covered, alpine terrain is often difficult and dangerous. Hence parameters such as snow depth or snow avalanche release and deposition zones are hard to map in situ with adequate spatial and temporal resolution and with spatial continuous coverage. These parameters are currently operationally measured at automated weather stations and by observer networks. However such isolated point measurements are not able to capture the information spatial continuous and to describe the high spatial variability present in complex mountain topography. Unmanned Aerial Systems (UAS) have the potential to fill this gap by frequently covering selected high alpine areas with high spatial resolution down to ground resolutions of even few millimeters. At the WSL Institute for Snow and Avalanche Research SLF we test different photogrammetric UAS with visual and near infrared bands. During the last three years we were able to gather experience in more than 100 flight missions in extreme terrain. By processing the imagery applying state-of-the-art structure from motion (SfM) software, we were able to accurately document several avalanche events and to photogrammetrically map snow depth with accuracies from 1 to 20 cm (dependent on the flight height above ground) compare to manual snow probe measurements. This was even possible on homogenous snow surfaces with very little texture. A key issue in alpine terrain is flight planning. We need to cover regions at high elevations with large altitude differences (up to 1 km) with high wind speeds (up to 20 m/s) and cold temperatures (down to - 25°C). Only a few UAS are able to cope with these environmental conditions. We will give an overview on our applications of UAS in high alpine terrain that demonstrate the big potential of such systems to acquire frequent, accurate and high spatial resolution geodata in high alpine, snow covered terrain that could be essential to answer longstanding questions in avalanche and snow hydrology

Method for Measuring the Information Content of Terrain from Digital Elevation Models

Directory of Open Access Journals (Sweden)

Lujin Hu

2015-10-01

Full Text Available As digital terrain models are indispensable for visualizing and modeling geographic processes, terrain information content is useful for terrain generalization and representation. For terrain generalization, if the terrain information is considered, the generalized terrain may be of higher fidelity. In other words, the richer the terrain information at the terrain surface, the smaller the degree of terrain simplification. Terrain information content is also important for evaluating the quality of the rendered terrain, e.g., the rendered web terrain tile service in Google Maps (Google Inc., Mountain View, CA, USA. However, a unified definition and measures for terrain information content have not been established. Therefore, in this paper, a definition and measures for terrain information content from Digital Elevation Model (DEM, i.e., a digital model or 3D representation of a terrain’s surface data are proposed and are based on the theory of map information content, remote sensing image information content and other geospatial information content. The information entropy was taken as the information measuring method for the terrain information content. Two experiments were carried out to verify the measurement methods of the terrain information content. One is the analysis of terrain information content in different geomorphic types, and the results showed that the more complex the geomorphic type, the richer the terrain information content. The other is the analysis of terrain information content with different resolutions, and the results showed that the finer the resolution, the richer the terrain information. Both experiments verified the reliability of the measurements of the terrain information content proposed in this paper.

A framework for WRF to WRF-IBM grid nesting to enable multiscale simulations

Energy Technology Data Exchange (ETDEWEB)

Wiersema, David John [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Univ. of California, Berkeley, CA (United States); Lundquist, Katherine A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Chow, Fotini Katapodes [Univ. of California, Berkeley, CA (United States)

2016-09-29

With advances in computational power, mesoscale models, such as the Weather Research and Forecasting (WRF) model, are often pushed to higher resolutions. As the model’s horizontal resolution is refined, the maximum resolved terrain slope will increase. Because WRF uses a terrain-following coordinate, this increase in resolved terrain slopes introduces additional grid skewness. At high resolutions and over complex terrain, this grid skewness can introduce large numerical errors that require methods, such as the immersed boundary method, to keep the model accurate and stable. Our implementation of the immersed boundary method in the WRF model, WRF-IBM, has proven effective at microscale simulations over complex terrain. WRF-IBM uses a non-conforming grid that extends beneath the model’s terrain. Boundary conditions at the immersed boundary, the terrain, are enforced by introducing a body force term to the governing equations at points directly beneath the immersed boundary. Nesting between a WRF parent grid and a WRF-IBM child grid requires a new framework for initialization and forcing of the child WRF-IBM grid. This framework will enable concurrent multi-scale simulations within the WRF model, improving the accuracy of high-resolution simulations and enabling simulations across a wide range of scales.

Recent developments and assessment of a three-dimensional PBL parameterization for improved wind forecasting over complex terrain

Science.gov (United States)

Kosovic, B.; Jimenez, P. A.; Haupt, S. E.; Martilli, A.; Olson, J.; Bao, J. W.

2017-12-01

At present, the planetary boundary layer (PBL) parameterizations available in most numerical weather prediction (NWP) models are one-dimensional. One-dimensional parameterizations are based on the assumption of horizontal homogeneity. This homogeneity assumption is appropriate for grid cell sizes greater than 10 km. However, for mesoscale simulations of flows in complex terrain with grid cell sizes below 1 km, the assumption of horizontal homogeneity is violated. Applying a one-dimensional PBL parameterization to high-resolution mesoscale simulations in complex terrain could result in significant error. For high-resolution mesoscale simulations of flows in complex terrain, we have therefore developed and implemented a three-dimensional (3D) PBL parameterization in the Weather Research and Forecasting (WRF) model. The implementation of the 3D PBL scheme is based on the developments outlined by Mellor and Yamada (1974, 1982). Our implementation in the Weather Research and Forecasting (WRF) model uses a pure algebraic model (level 2) to diagnose the turbulent fluxes. To evaluate the performance of the 3D PBL model, we use observations from the Wind Forecast Improvement Project 2 (WFIP2). The WFIP2 field study took place in the Columbia River Gorge area from 2015-2017. We focus on selected cases when physical phenomena of significance for wind energy applications such as mountain waves, topographic wakes, and gap flows were observed. Our assessment of the 3D PBL parameterization also considers a large-eddy simulation (LES). We carried out a nested LES with grid cell sizes of 30 m and 10 m covering a large fraction of the WFIP2 study area. Both LES domains were discretized using 6000 x 3000 x 200 grid cells in zonal, meridional, and vertical direction, respectively. The LES results are used to assess the relative magnitude of horizontal gradients of turbulent stresses and fluxes in comparison to vertical gradients. The presentation will highlight the advantages of the 3

A new method for determination of most likely landslide initiation points and the evaluation of digital terrain model scale in terrain stability mapping

Directory of Open Access Journals (Sweden)

P. Tarolli

2006-01-01

Full Text Available This paper introduces a new approach for determining the most likely initiation points for landslides from potential instability mapped using a terrain stability model. This approach identifies the location with critical stability index from a terrain stability model on each downslope path from ridge to valley. Any measure of terrain stability may be used with this approach, which here is illustrated using results from SINMAP, and from simply taking slope as an index of potential instability. The relative density of most likely landslide initiation points within and outside mapped landslide scars provides a way to evaluate the effectiveness of a terrain stability measure, even when mapped landslide scars include run out zones, rather than just initiation locations. This relative density was used to evaluate the utility of high resolution terrain data derived from airborne laser altimetry (LIDAR for a small basin located in the Northeastern Region of Italy. Digital Terrain Models were derived from the LIDAR data for a range of grid cell sizes (from 2 to 50 m. We found appreciable differences between the density of most likely landslide initiation points within and outside mapped landslides with ratios as large as three or more with the highest ratios for a digital terrain model grid cell size of 10 m. This leads to two conclusions: (1 The relative density from a most likely landslide initiation point approach is useful for quantifying the effectiveness of a terrain stability map when mapped landslides do not or can not differentiate between initiation, runout, and depositional areas; and (2 in this study area, where landslides occurred in complexes that were sometimes more than 100 m wide, a digital terrain model scale of 10 m is optimal. Digital terrain model scales larger than 10 m result in loss of resolution that degrades the results, while for digital terrain model scales smaller than 10 m the physical processes responsible for triggering

Running over unknown rough terrain with a one-legged planar robot

International Nuclear Information System (INIS)

Andrews, Ben; Miller, Bruce; Clark, Jonathan E; Schmitt, John

2011-01-01

The ability to traverse unknown, rough terrain is an advantage that legged locomoters have over their wheeled counterparts. However, due to the complexity of multi-legged systems, research in legged robotics has not yet been able to reproduce the agility found in the animal kingdom. In an effort to reduce the complexity of the problem, researchers have developed single-legged models to gain insight into the fundamental dynamics of legged running. Inspired by studies of animal locomotion, researchers have proposed numerous control strategies to achieve stable, one-legged running over unknown, rough terrain. One such control strategy incorporates energy variations into the system during the stance phase by changing the force-free leg length as a sinusoidal function of time. In this research, a one-legged planar robot capable of implementing this and other state-of-the-art control strategies was designed and built. Both simulated and experimental results were used to determine and compare the stability of the proposed controllers as the robot was subjected to unknown drop and raised step perturbations equal to 25% of the nominal leg length. This study illustrates the relative advantages of utilizing a minimal-sensing, active energy removal control scheme to stabilize running over rough terrain.

Wind farm design in complex terrain: the FarmOpt methodology

DEFF Research Database (Denmark)

Feng, Ju

Designing wind farms in complex terrain is becoming more and more important, especially for countries like China, where a large portion of the territory is featured as complex terrain. Although potential richer wind resources could be expected at complex terrain sites (thanks to the terrain effec...

Weightless environment simulation test; Mujuryo simulation shiken

Energy Technology Data Exchange (ETDEWEB)

Kobayashi, K.; Yamamoto, T.; Kato, F. [Kawasaki Heavy Industries, Ltd., Kobe (Japan)

1997-07-20

Kawasaki Heavy Industries, Ltd., delivered a Weightless Environment Test System (WETS) to National Space Development Agency of Japan in 1994. This system creates a weightless environment similar to that in space by balancing gravity and buoyancy in the water, and is constituted of a large water tank, facilities to supply air and cooling water to space suits worn in the water, etc. In this report, a weightless environment simulation test and the facilities to supply air and cooling water are described. In the weightless environment simulation test, the astronaut to undergo tests and training wears a space suit quite similar to the suit worn on the orbit, and performs EVA/IVA (extravehicular activities/intravehicular activities) around a JEM (Japanese Experimental Module) mockup installed in the water verifying JEM design specifications, preparing manuals for operations on the orbit, or receives basic space-related drill and training. An EVA weightless environment simulation test No. 3 was accomplished with success in January, 1997, when the supply of breathing water and cooling water to the space suit, etc., were carried out with safety and reliability. 2 refs., 8 figs., 2 tabs.

GIS TECHNOLOGY AND TERRAIN ORTHOPHOTOMAP MAKING FOR MILITARY APPLICATION

Directory of Open Access Journals (Sweden)

Elshan Hashimov

2017-11-01

Full Text Available In this paper, it is shown that GIS and photogrammetry technologiyes, determination of searching target coordinates for the operational desicion making are very important for the military application, for the combat control. With aim of orthophotomap making of the terrain and identification of terrain supervision there has been constructed 3D model for choosen mountainous terrain of Azerbaijan Republic using GIS technology. Based on this model there has been obtained a terrain profile and carried out mapping. Using ArcGis software there has been investigated possibility remain control on obserbvable and unobservable parties of terrain on supervision line from supervision point to target point.

GPS test range mission planning

Science.gov (United States)

Roberts, Iris P.; Hancock, Thomas P.

The principal features of the Test Range User Mission Planner (TRUMP), a PC-resident tool designed to aid in deploying and utilizing GPS-based test range assets, are reviewed. TRUMP features time history plots of time-space-position information (TSPI); performance based on a dynamic GPS/inertial system simulation; time history plots of TSPI data link connectivity; digital terrain elevation data maps with user-defined cultural features; and two-dimensional coverage plots of ground-based test range assets. Some functions to be added during the next development phase are discussed.

Automatic terrain modeling using transfinite element analysis

KAUST Repository

Collier, Nathan; Calo, Victor M.

2010-01-01

An automatic procedure for modeling terrain is developed based on L2 projection-based interpolation of discrete terrain data onto transfinite function spaces. The function space is refined automatically by the use of image processing techniques

Atmospheric flow over terrain using hybrid RANS/LES

DEFF Research Database (Denmark)

Bechmann, Andreas; Sørensen, Niels N.; Johansen, Jeppe

2007-01-01

Due to years of growth in installed wind power, new sites for wind turbines are in constant demand. With increased use of ever more complex sites, local wind phenomena can be expected to greatly increase the load on wind turbines. This work describes how Large-Eddy Simulation (LES) can be used...... to estimate the wind in complex terrain. A newly developed LES-model is presented and is validated by predicting the wind over the Askervein hill. We believe, that the ability of LES to capture load generating turbulent structures like wind gusts, is crucial for further development of complex sites....

Wind field and dispersion modelling in complex terrain

International Nuclear Information System (INIS)

Bartzis, J.G.; Varvayanni, M.; Catsaros, N.; Konte, K.; Amanatidis, G.

1991-01-01

Dispersion of airborne radioactive material can have an important environmental impact. Its prediction remains a difficult problem, especially over complex and inhomogeneous terrain, or under complicated atmospheric conditions. The ADREA-I code, a three-dimensional transport code especially designed for terrains of high complexity can be considered as contribution to the solution of the above problem. The code development has been initiated within the present CEC Radiation Program. New features are introduced into the code to describe the anomalous topography, the turbulent diffusion and numerical solution procedures. In this work besides a brief presentation of the main features of the code, a number of applications will be presented with the aim on one hand to illustrate the capability and reliability of the code and on the other hand to clarify the effects on windfield and dispersion in special cases of interest. Within the framework of ADREA-I verification studies, a I-D simulation of the experimental Wangara Day-33 mean boundary layer was attempted, reproducing the daytime wind speeds, temperatures, specific humidities and mixing depths. In order to address the effect of surface irregularities and inhomogeneities on contamination patterns, the flow field and dispersion were analyzed over a 2-D, 1000m high mountain range, surrounded by sea, with a point source assumed 40km offshore from one coastline. This terrain was studied as representing a greater Athens area idealization. The effects of a 2-D, 1000m high mountain range of Gaussian shape on long range transport has also been studied in terms of influence area, wind and concentration profile distortions and dry deposition patterns

Procedure and layout for the development of a fatigue test on an agricultural implement by a four poster test bench

Directory of Open Access Journals (Sweden)

M. Cutini

2013-09-01

Full Text Available The increasing demand in agricultural vehicles’ power requirements, payloads and driving speeds increases issues related to tractors and farm implements exposure to solicitations. One of the main factors to be taken into account for fatigue test developing on agricultural machines is the heterogeneity of the environment and activity in which the tractor operates. In particular, for contractors the use in transport conditions both on terrain and road becomes important. As far as transport is concerned. factors mainly affecting solicitations on carried implement are soil profile roughness, tractor settings and forward speed. In this paper, CRA-ING laboratory of Treviglio, Italy, together with Frandent Group s.r.l. (Osasco, Italy, analyse the possibility of creating a solicitation profile by means of one four poster test bench for fatigue test on a carried implement simulating transport conditions. Accelerations at the hubs of the tractor were acquired during transport on terrain and reproduced with one electro-hydraulic four posters test bench on one dummy of a tractor developed for carrying the implement. Artificial bumps were mathematically created and introduced in the time history to simulate squares solicitations. Twelve hours of test were carried out. This experience confirmed the possibility of carrying out laboratory fatigue test on agricultural implements by reproducing specific field conditions solicitations with four poster test bench.

Cross-Coupled Control for All-Terrain Rovers

Directory of Open Access Journals (Sweden)

Giulio Reina

2013-01-01

Full Text Available Mobile robots are increasingly being used in challenging outdoor environments for applications that include construction, mining, agriculture, military and planetary exploration. In order to accomplish the planned task, it is critical that the motion control system ensure accuracy and robustness. The achievement of high performance on rough terrain is tightly connected with the minimization of vehicle-terrain dynamics effects such as slipping and skidding. This paper presents a cross-coupled controller for a 4-wheel-drive/4-wheel-steer robot, which optimizes the wheel motors’ control algorithm to reduce synchronization errors that would otherwise result in wheel slip with conventional controllers. Experimental results, obtained with an all-terrain rover operating on agricultural terrain, are presented to validate the system. It is shown that the proposed approach is effective in reducing slippage and vehicle posture errors.

Stratigraphy of the layered terrain in Valles Marineris, Mars

Science.gov (United States)

Komatsu, G.; Strom, Roger G.

1991-01-01

The layered terrain in Valles Marineris provides information about its origin and the geologic history of this canyon system. Whether the terrain is sedimentary material deposited in a dry or lacustrine environment, or volcanic material related to the tectonics of the canyon is still controversial. However, recent studies of Gangis Layered Terrain suggests a cyclic sequence of deposition and erosion under episodic lacustrine conditions. The stratigraphic studies are extended to four other occurrences of layered terrains in Valles Marineris in an attempt to correlate and distinguish between depositional environments. The Juvantae Chasma, Hebes Chasma, Ophir and Candor Chasmata, Melas Chasma, and Gangis Layered Terrain were examined. Although there are broad similarities among the layered terrains, no two deposits are exactly alike. This suggests that there was no synchronized regional depositional processes to form all the layered deposits. However, the similar erosional style of the lower massive weakly bedded unit in Hebes, Gangis, and Ophir-Candor suggests it may have been deposited under similar circumstances.

Stereo-vision-based terrain mapping for off-road autonomous navigation

Science.gov (United States)

Rankin, Arturo L.; Huertas, Andres; Matthies, Larry H.

2009-05-01

Successful off-road autonomous navigation by an unmanned ground vehicle (UGV) requires reliable perception and representation of natural terrain. While perception algorithms are used to detect driving hazards, terrain mapping algorithms are used to represent the detected hazards in a world model a UGV can use to plan safe paths. There are two primary ways to detect driving hazards with perception sensors mounted to a UGV: binary obstacle detection and traversability cost analysis. Binary obstacle detectors label terrain as either traversable or non-traversable, whereas, traversability cost analysis assigns a cost to driving over a discrete patch of terrain. In uncluttered environments where the non-obstacle terrain is equally traversable, binary obstacle detection is sufficient. However, in cluttered environments, some form of traversability cost analysis is necessary. The Jet Propulsion Laboratory (JPL) has explored both approaches using stereo vision systems. A set of binary detectors has been implemented that detect positive obstacles, negative obstacles, tree trunks, tree lines, excessive slope, low overhangs, and water bodies. A compact terrain map is built from each frame of stereo images. The mapping algorithm labels cells that contain obstacles as nogo regions, and encodes terrain elevation, terrain classification, terrain roughness, traversability cost, and a confidence value. The single frame maps are merged into a world map where temporal filtering is applied. In previous papers, we have described our perception algorithms that perform binary obstacle detection. In this paper, we summarize the terrain mapping capabilities that JPL has implemented during several UGV programs over the last decade and discuss some challenges to building terrain maps with stereo range data.

Numerical simulations of rubber bearing tests and shaking table tests

International Nuclear Information System (INIS)

Hirata, K.; Matsuda, A.; Yabana, S.

2002-01-01

Test data concerning rubber bearing tests and shaking table tests of base-isolated model conducted by CRIEPI are provided to the participants of Coordinated Research Program (CRP) on 'Intercomparison of Analysis Methods for predicting the behaviour of Seismically Isolated Nuclear Structure', which is organized by International Atomic Energy Agency (IAEA), for the comparison study of numerical simulation of base-isolated structure. In this paper outlines of the test data provided and the numerical simulations of bearing tests and shaking table tests are described. Using computer code ABAQUS, numerical simulations of rubber bearing tests are conducted for NRBs, LRBs (data provided by CRIEPI) and for HDRs (data provided by ENEA/ENEL and KAERI). Several strain energy functions are specified according to the rubber material test corresponding to each rubber bearing. As for lead plug material in LRB, mechanical characteristics are reevaluated and are made use of. Simulation results for these rubber bearings show satisfactory agreement with the test results. Shaking table test conducted by CRIEPI is of a base isolated rigid mass supported by LRB. Acceleration time histories, displacement time histories of the isolators as well as cyclic loading test data of the LRB used for the shaking table test are provided to the participants of the CRP. Simulations of shaking table tests are conducted for this rigid mass, and also for the steel frame model which is conducted by ENEL/ENEA. In the simulation of the rigid mass model test, where LRBs are used, isolators are modeled either by bilinear model or polylinear model. In both cases of modeling of isolators, simulation results show good agreement with the test results. In the case of the steel frame model, where HDRs are used as isolators, bilinear model and polylinear model are also used for modeling isolators. The response of the model is simulated comparatively well in the low frequency range of the floor response, however, in

Simulant Development for LAWPS Testing

Energy Technology Data Exchange (ETDEWEB)

Russell, Renee L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Schonewill, Philip P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Burns, Carolyn A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2017-05-23

This report describes simulant development work that was conducted to support the technology maturation of the LAWPS facility. Desired simulant physical properties (density, viscosity, solids concentration, solid particle size), sodium concentrations, and general anion identifications were provided by WRPS. The simulant recipes, particularly a “nominal” 5.6M Na simulant, are intended to be tested at several scales, ranging from bench-scale (500 mL) to full-scale. Each simulant formulation was selected to be chemically representative of the waste streams anticipated to be fed to the LAWPS system, and used the current version of the LAWPS waste specification as a formulation basis. After simulant development iterations, four simulants of varying sodium concentration (5.6M, 6.0M, 4.0M, and 8.0M) were prepared and characterized. The formulation basis, development testing, and final simulant recipes and characterization data for these four simulants are presented in this report.

Numerical simulation of the aerodynamic field in complex terrain wind farm based on actuator disk model

DEFF Research Database (Denmark)

Xu, Chang; Li, Chen Qi; Han, Xing Xing

2015-01-01

Study on the aerodynamic field in complex terrain is significant to wind farm micro-sitting and wind power prediction. This paper modeled the wind turbine through an actuator disk model, and solved the aerodynamic field by CFD to study the influence of meshing, boundary conditions and turbulence ...

Simulation-based Testing of Control Software

Energy Technology Data Exchange (ETDEWEB)

Ozmen, Ozgur [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Nutaro, James J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sanyal, Jibonananda [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Olama, Mohammed M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2017-02-10

It is impossible to adequately test complex software by examining its operation in a physical prototype of the system monitored. Adequate test coverage can require millions of test cases, and the cost of equipment prototypes combined with the real-time constraints of testing with them makes it infeasible to sample more than a small number of these tests. Model based testing seeks to avoid this problem by allowing for large numbers of relatively inexpensive virtual prototypes that operate in simulation time at a speed limited only by the available computing resources. In this report, we describe how a computer system emulator can be used as part of a model based testing environment; specifically, we show that a complete software stack including operating system and application software - can be deployed within a simulated environment, and that these simulations can proceed as fast as possible. To illustrate this approach to model based testing, we describe how it is being used to test several building control systems that act to coordinate air conditioning loads for the purpose of reducing peak demand. These tests involve the use of ADEVS (A Discrete Event System Simulator) and QEMU (Quick Emulator) to host the operational software within the simulation, and a building model developed with the MODELICA programming language using Buildings Library and packaged as an FMU (Functional Mock-up Unit) that serves as the virtual test environment.

Photometric diversity of terrains on Triton

Science.gov (United States)

Hillier, J.; Veverka, J.; Helfenstein, P.; Lee, P.

1994-01-01

Voyager disk-resolved images of Triton in the violet (0.41 micrometers) and green (0.56 micrometer wavelengths have been analyzed to derive the photometric characteristics of terrains on Triton. Similar conclusions are found using two distinct but related definitions of photometric units, one based on color ratio and albedo properties (A. S. McEwen, 1990), the other on albedo and brightness ratios at different phase angles (P. Lee et al., 1992). A significant diversity of photometric behavior, much broader than that discovered so far on any other icy satellite, occurs among Triton's terrains. Remarkably, differences in photometric behavior do not correlate well with geologic terrain boundaries defined on the basis of surface morphology. This suggests that in most cases photometric properties on Triton are controlled by thin deposits superposed on underlying geologic units. Single scattering albedos are 0.98 or higher and asymmetry factors range from -0.35 to -0.45 for most units. The most distinct scattering behavior is exhibited by the reddish northern units already identified as the Anomalously Scattering Region (ASR), which scatters light almost isotropically with g = -0.04. In part due to the effects of Triton's clouds and haze, it is difficult to constrain the value of bar-theta, Hapke's macroscopic roughness parameter, precisely for Triton or to map differences in bar-theta among the different photometric terrains. However, our study shows that Triton must be relatively smooth, with bar-theta less than 15-20 degs and suggests that a value of 14 degs is appropriate. The differences in photometric characteristics lead to significantly different phase angle behavior for the various terrains. For example, a terrain (e.g., the ASR) that appears dark relative to another at low phase angles will reverse its contrast (become relatively brighter) at larger phase angles. The photometric parameters have been used to calculate hemispherical albedos for the units and to

What model resolution is required in climatological downscaling over complex terrain?

Science.gov (United States)

El-Samra, Renalda; Bou-Zeid, Elie; El-Fadel, Mutasem

2018-05-01

This study presents results from the Weather Research and Forecasting (WRF) model applied for climatological downscaling simulations over highly complex terrain along the Eastern Mediterranean. We sequentially downscale general circulation model results, for a mild and wet year (2003) and a hot and dry year (2010), to three local horizontal resolutions of 9, 3 and 1 km. Simulated near-surface hydrometeorological variables are compared at different time scales against data from an observational network over the study area comprising rain gauges, anemometers, and thermometers. The overall performance of WRF at 1 and 3 km horizontal resolution was satisfactory, with significant improvement over the 9 km downscaling simulation. The total yearly precipitation from WRF's 1 km and 3 km domains exhibited quantitative measure of the potential errors for various hydrometeorological variables.

Parallel Implementation of the Terrain Masking Algorithm

Science.gov (United States)

1994-03-01

contains behavior rules which can define a computation or an algorithm. It can communicate with other process nodes, it can contain local data, and it can...terrain maskirg calculation is being performed. It is this algorithm that comsumes about seventy percent of the total terrain masking calculation time

A GPS inspired Terrain Referenced Navigation algorithm

NARCIS (Netherlands)

Vaman, D.

2014-01-01

Terrain Referenced Navigation (TRN) refers to a form of localization in which measurements of distances to the terrain surface are matched with a digital elevation map allowing a vehicle to estimate its own position within the map. The main goal of this dissertation is to improve TRN performance

EARTHWORK VOLUME CALCULATION FROM DIGITAL TERRAIN MODELS

Directory of Open Access Journals (Sweden)

JANIĆ Milorad

2015-06-01

Full Text Available Accurate calculation of cut and fill volume has an essential importance in many fields. This article shows a new method, which has no approximation, based on Digital Terrain Models. A relatively new mathematical model is developed for that purpose, which is implemented in the software solution. Both of them has been tested and verified in the praxis on several large opencast mines. This application is developed in AutoLISP programming language and works in AutoCAD environment.

Walking Robots Dynamic Control Systems on an Uneven Terrain

Directory of Open Access Journals (Sweden)

MUNTEANU, M. S.

2010-05-01

Full Text Available The paper presents ZPM dynamic control of walking robots, developing an open architecture real time control multiprocessor system, in view of obtaining new capabilities for walking robots. The complexity of the movement mechanism of a walking robot was taken into account, being a repetitive tilting process with numerous instable movements and which can lead to its turnover on an uneven terrain. The control system architecture for the dynamic robot walking is presented in correlation with the control strategy which contains three main real time control loops: balance robot control using sensorial feedback, walking diagram control with periodic changes depending on the sensorial information during each walk cycle, predictable movement control based on a quick decision from the previous experimental data. The results obtained through simulation and experiments show an increase in mobility, stability in real conditions and obtaining of high performances related to the possibility of moving walking robots on terrains with a configuration as close as possible to real situations, respectively developing new technological capabilities of the walking robot control systems for slope movement and walking by overtaking or going around obstacles.

Environmental impacts of forest road construction on mountainous terrain.

Science.gov (United States)

Caliskan, Erhan

2013-03-15

Forest roads are the base infrastructure foundation of forestry operations. These roads entail a complex engineering effort because they can cause substantial environmental damage to forests and include a high-cost construction. This study was carried out in four sample sites of Giresun, Trabzon(2) and Artvin Forest Directorate, which is in the Black Sea region of Turkey. The areas have both steep terrain (30-50% gradient) and very steep terrain (51-80% gradient). Bulldozers and hydraulic excavators were determined to be the main machines for forest road construction, causing environmental damage and cross sections in mountainous areas.As a result of this study, the percent damage to forests was determined as follows: on steep terrain, 21% of trees were damaged by excavators and 33% of trees were damaged by bulldozers during forest road construction, and on very steep terrain, 27% of trees were damaged by excavators and 44% of trees were damaged by bulldozers during forest road construction. It was also determined that on steep terrain, when excavators were used, 12.23% less forest area was destroyed compared with when bulldozers were used and 16.13% less area was destroyed by excavators on very steep terrain. In order to reduce the environmental damage on the forest ecosystem, especially in steep terrains, hydraulic excavators should replace bulldozers in forest road construction activities.

Environmental Impacts of Forest Road Construction on Mountainous Terrain

Directory of Open Access Journals (Sweden)

Erhan Caliskan

2013-03-01

Full Text Available Forest roads are the base infrastructure foundation of forestry operations. These roads entail a complex engineering effort because they can cause substantial environmental damage to forests and include a high-cost construction. This study was carried out in four sample sites of Giresun, Trabzon(2 and Artvin Forest Directorate, which is in the Black Sea region of Turkey. The areas have both steep terrain (30-50% gradient and very steep terrain (51-80% gradient. Bulldozers and hydraulic excavators were determined to be the main machines for forest road construction, causing environmental damage and cross sections in mountainous areas.As a result of this study, the percent damage to forests was determined as follows: on steep terrain, 21% of trees were damaged by excavators and 33% of trees were damaged by bulldozers during forest road construction, and on very steep terrain, 27% of trees were damaged by excavators and 44% of trees were damaged by bulldozers during forest road construction. It was also determined that on steep terrain, when excavators were used, 12.23% less forest area was destroyed compared with when bulldozers were used and 16.13% less area was destroyed by excavators on very steep terrain. In order to reduce the environmental damage on the forest ecosystem, especially in steep terrains, hydraulic excavators should replace bulldozers in forest road construction activities.

Computing visibility on terrains in external memory

NARCIS (Netherlands)

Haverkort, H.J.; Toma, L.; Zhuang, Yi

2007-01-01

We describe a novel application of the distribution sweeping technique to computing visibility on terrains. Given an arbitrary viewpoint v, the basic problem we address is computing the visibility map or viewshed of v, which is the set of points in the terrain that are visible from v. We give the

47 CFR 80.759 - Average terrain elevation.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Average terrain elevation. 80.759 Section 80.759 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE MARITIME SERVICES Standards for Computing Public Coast Station VHF Coverage § 80.759 Average terrain elevation. (a)(1) Draw radials...

The influence of terrain forcing on the initiation of deep convection over Mediterranean islands

Science.gov (United States)

Barthlott, Christian; Kirshbaum, Daniel

2013-04-01

The influence of mountainous islands on the initiation of deep convection is investigated using the Consortium for Small-scale Modeling (COSMO) model. The study day is 26 August 2009 on which moist convection occurred over both the Corsica and Sardinia island in the Mediterranean Sea. Sensitivity runs with systematically modified topography are explored to evaluate the relative importance of the land-sea contrast and the terrain height for convection initiation. Whereas no island precipitation is simulated when the islands are completely removed, all simulations that represent these land surfaces develop convective precipitation. Although convection initiates progressively earlier in the day over taller islands, the precipitation rates and accumulations do not show a fixed relationship with terrain height. This is due to the competing effects of different physical processes. First, whereas the forcing for low-level ascent increases over taller islands, the boundary-layer moisture supply decreases, which diminishes the conditional instability and precipitable water. Second, whereas taller islands enhance the inland propagation speeds of sea-breeze fronts, they also mechanically block these fronts and prevent them from reaching the island interior. As a result, the island precipitation is rather insensitive to island terrain height except for one particular case in which the island precipitation increases considerably due to an optimal superposition of the sea breeze and upslope flow. These results demonstrate the complexity of interactions between sea breezes and orography and reinforce that an adequate representation of detailed topographic features is necessary to account for thermally induced wind systems that initiate deep convection.

Improved visibility computation on massive grid terrains

NARCIS (Netherlands)

Fishman, J.; Haverkort, H.J.; Toma, L.; Wolfson, O.; Agrawal, D.; Lu, C.-T.

2009-01-01

This paper describes the design and engineering of algorithms for computing visibility maps on massive grid terrains. Given a terrain T, specified by the elevations of points in a regular grid, and given a viewpoint v, the visibility map or viewshed of v is the set of grid points of T that are

Terrain Classification of Norwegian Slab Avalanche Accidents

Science.gov (United States)

Hallandvik, Linda; Aadland, Eivind; Vikene, Odd Lennart

2016-01-01

It is difficult to rely on snow conditions, weather, and human factors when making judgments about avalanche risk because these variables are dynamic and complex; terrain, however, is more easily observed and interpreted. Therefore, this study aimed to investigate (1) the type of terrain in which historical fatal snow avalanche accidents in Norway…

Sensitivity of a carbon and productivity model to climatic, water, terrain, and biophysical parameters in a Rocky Mountain watershed

Energy Technology Data Exchange (ETDEWEB)

Xu, S.; Peddle, D.R.; Coburn, C.A.; Kienzle, S. [Univ. of Lethbridge, Dept. of Geography, Lethbridge, Alberta (Canada)

2008-06-15

Net primary productivity (NPP) is a key component of the terrestrial carbon cycle and is important in ecological, watershed, and forest management studies, and more broadly in global climate change research. Determining the relative importance and magnitude of uncertainty of NPP model inputs is important for proper carbon reporting over larger areas and time periods. This paper presents a systematic evaluation of the boreal ecosystem productivity simulator (BEPS) model in mountainous terrain using an established montane forest test site in Kananaskis, Alberta, in the Canadian Rocky Mountains. Model runs were based on forest (land cover, leaf area index (LAI), biomass) and climate-water inputs (solar radiation, temperature, precipitation, humidity, soil water holding capacity) derived from digital elevation model (DEM) derivatives, climate data, geographical information system (GIS) functions, and topographically corrected satellite imagery. Four sensitivity analyses were conducted as a controlled series of experiments involving (i) NPP individual parameter sensitivity for a full growing season, (ii) NPP independent variation tests (parameter {mu} {+-} 1{sigma}), (iii) factorial analyses to assess more complex multiple-factor interactions, and (iv) topographic correction. The results, validated against field measurements, showed that modeled NPP was sensitive to most inputs measured in the study area, with LAI and forest type the most important forest input, and solar radiation the most important climate input. Soil available water holding capacity expressed as a function of wetness index was only significant in conjunction with precipitation when both parameters represented a moisture-deficit situation. NPP uncertainty resulting from topographic influence was equivalent to 140 kg C ha{sup -1}{center_dot}year{sup -1}. This suggested that topographic correction of model inputs is important for accurate NPP estimation. The BEPS model, designed originally for flat

Sensitivity of a carbon and productivity model to climatic, water, terrain, and biophysical parameters in a Rocky Mountain watershed

International Nuclear Information System (INIS)

Xu, S.; Peddle, D.R.; Coburn, C.A.; Kienzle, S.

2008-01-01

Net primary productivity (NPP) is a key component of the terrestrial carbon cycle and is important in ecological, watershed, and forest management studies, and more broadly in global climate change research. Determining the relative importance and magnitude of uncertainty of NPP model inputs is important for proper carbon reporting over larger areas and time periods. This paper presents a systematic evaluation of the boreal ecosystem productivity simulator (BEPS) model in mountainous terrain using an established montane forest test site in Kananaskis, Alberta, in the Canadian Rocky Mountains. Model runs were based on forest (land cover, leaf area index (LAI), biomass) and climate-water inputs (solar radiation, temperature, precipitation, humidity, soil water holding capacity) derived from digital elevation model (DEM) derivatives, climate data, geographical information system (GIS) functions, and topographically corrected satellite imagery. Four sensitivity analyses were conducted as a controlled series of experiments involving (i) NPP individual parameter sensitivity for a full growing season, (ii) NPP independent variation tests (parameter μ ± 1σ), (iii) factorial analyses to assess more complex multiple-factor interactions, and (iv) topographic correction. The results, validated against field measurements, showed that modeled NPP was sensitive to most inputs measured in the study area, with LAI and forest type the most important forest input, and solar radiation the most important climate input. Soil available water holding capacity expressed as a function of wetness index was only significant in conjunction with precipitation when both parameters represented a moisture-deficit situation. NPP uncertainty resulting from topographic influence was equivalent to 140 kg C ha -1 ·year -1 . This suggested that topographic correction of model inputs is important for accurate NPP estimation. The BEPS model, designed originally for flat boreal forests, was shown to be

Wind Tunnel Modeling Of Wind Flow Over Complex Terrain

Science.gov (United States)

Banks, D.; Cochran, B.

2010-12-01

This presentation will describe the finding of an atmospheric boundary layer (ABL) wind tunnel study conducted as part of the Bolund Experiment. This experiment was sponsored by Risø DTU (National Laboratory for Sustainable Energy, Technical University of Denmark) during the fall of 2009 to enable a blind comparison of various air flow models in an attempt to validate their performance in predicting airflow over complex terrain. Bohlund hill sits 12 m above the water level at the end of a narrow isthmus. The island features a steep escarpment on one side, over which the airflow can be expected to separate. The island was equipped with several anemometer towers, and the approach flow over the water was well characterized. This study was one of only two only physical model studies included in the blind model comparison, the other being a water plume study. The remainder were computational fluid dynamics (CFD) simulations, including both RANS and LES. Physical modeling of air flow over topographical features has been used since the middle of the 20th century, and the methods required are well understood and well documented. Several books have been written describing how to properly perform ABL wind tunnel studies, including ASCE manual of engineering practice 67. Boundary layer wind tunnel tests are the only modelling method deemed acceptable in ASCE 7-10, the most recent edition of the American Society of Civil Engineers standard that provides wind loads for buildings and other structures for buildings codes across the US. Since the 1970’s, most tall structures undergo testing in a boundary layer wind tunnel to accurately determine the wind induced loading. When compared to CFD, the US EPA considers a properly executed wind tunnel study to be equivalent to a CFD model with infinitesimal grid resolution and near infinite memory. One key reason for this widespread acceptance is that properly executed ABL wind tunnel studies will accurately simulate flow separation

Nuclear system test simulator

International Nuclear Information System (INIS)

Sawyer, S.D.; Hill, W.D.; Wilson, P.A.; Steiner, W.M.

1987-01-01

A transportable test simulator is described for a nuclear power plant. The nuclear power plant includes a control panel, a reactor having actuated rods for moving into and out of a reactor for causing the plant to operate, and a control rod network extending between the control panel and the reactor rods. The network serially transmits command words between the panel and rods, and has connecting interfaces at preselected points remote from the control panel between the control panel and rods. The test simulator comprises: a test simulator input for transport to and connection into the network at at least one interface for receiving the serial command words from the network. Each serial command includes an identifier portion and a command portion; means for processing interior of the simulator for the serial command words for identifying that portion of the power plant designated in the identifier portion and processing the word responsive to the command portion of the word after the identification; means for generating a response word responsive to the command portion; and output means for sending and transmitting the response word to the nuclear power plant at the interface whereby the control panel responds to the response word

Nesting Large-Eddy Simulations Within Mesoscale Simulations for Wind Energy Applications

Science.gov (United States)

Lundquist, J. K.; Mirocha, J. D.; Chow, F. K.; Kosovic, B.; Lundquist, K. A.

2008-12-01

With increasing demand for more accurate atmospheric simulations for wind turbine micrositing, for operational wind power forecasting, and for more reliable turbine design, simulations of atmospheric flow with resolution of tens of meters or higher are required. These time-dependent large-eddy simulations (LES) account for complex terrain and resolve individual atmospheric eddies on length scales smaller than turbine blades. These small-domain high-resolution simulations are possible with a range of commercial and open- source software, including the Weather Research and Forecasting (WRF) model. In addition to "local" sources of turbulence within an LES domain, changing weather conditions outside the domain can also affect flow, suggesting that a mesoscale model provide boundary conditions to the large-eddy simulations. Nesting a large-eddy simulation within a mesoscale model requires nuanced representations of turbulence. Our group has improved the Weather and Research Forecating model's (WRF) LES capability by implementing the Nonlinear Backscatter and Anisotropy (NBA) subfilter stress model following Kosoviæ (1997) and an explicit filtering and reconstruction technique to compute the Resolvable Subfilter-Scale (RSFS) stresses (following Chow et al, 2005). We have also implemented an immersed boundary method (IBM) in WRF to accommodate complex terrain. These new models improve WRF's LES capabilities over complex terrain and in stable atmospheric conditions. We demonstrate approaches to nesting LES within a mesoscale simulation for farms of wind turbines in hilly regions. Results are sensitive to the nesting method, indicating that care must be taken to provide appropriate boundary conditions, and to allow adequate spin-up of turbulence in the LES domain. This work is performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Virtual terrain: a security-based representation of a computer network

Science.gov (United States)

Holsopple, Jared; Yang, Shanchieh; Argauer, Brian

2008-03-01

Much research has been put forth towards detection, correlating, and prediction of cyber attacks in recent years. As this set of research progresses, there is an increasing need for contextual information of a computer network to provide an accurate situational assessment. Typical approaches adopt contextual information as needed; yet such ad hoc effort may lead to unnecessary or even conflicting features. The concept of virtual terrain is, therefore, developed and investigated in this work. Virtual terrain is a common representation of crucial information about network vulnerabilities, accessibilities, and criticalities. A virtual terrain model encompasses operating systems, firewall rules, running services, missions, user accounts, and network connectivity. It is defined as connected graphs with arc attributes defining dynamic relationships among vertices modeling network entities, such as services, users, and machines. The virtual terrain representation is designed to allow feasible development and maintenance of the model, as well as efficacy in terms of the use of the model. This paper will describe the considerations in developing the virtual terrain schema, exemplary virtual terrain models, and algorithms utilizing the virtual terrain model for situation and threat assessment.

LOD-based clustering techniques for efficient large-scale terrain storage and visualization

Science.gov (United States)

Bao, Xiaohong; Pajarola, Renato

2003-05-01

Large multi-resolution terrain data sets are usually stored out-of-core. To visualize terrain data at interactive frame rates, the data needs to be organized on disk, loaded into main memory part by part, then rendered efficiently. Many main-memory algorithms have been proposed for efficient vertex selection and mesh construction. Organization of terrain data on disk is quite difficult because the error, the triangulation dependency and the spatial location of each vertex all need to be considered. Previous terrain clustering algorithms did not consider the per-vertex approximation error of individual terrain data sets. Therefore, the vertex sequences on disk are exactly the same for any terrain. In this paper, we propose a novel clustering algorithm which introduces the level-of-detail (LOD) information to terrain data organization to map multi-resolution terrain data to external memory. In our approach the LOD parameters of the terrain elevation points are reflected during clustering. The experiments show that dynamic loading and paging of terrain data at varying LOD is very efficient and minimizes page faults. Additionally, the preprocessing of this algorithm is very fast and works from out-of-core.

Creating and Testing Simulation Software

Science.gov (United States)

Heinich, Christina M.

2013-01-01

The goal of this project is to learn about the software development process, specifically the process to test and fix components of the software. The paper will cover the techniques of testing code, and the benefits of using one style of testing over another. It will also discuss the overall software design and development lifecycle, and how code testing plays an integral role in it. Coding is notorious for always needing to be debugged due to coding errors or faulty program design. Writing tests either before or during program creation that cover all aspects of the code provide a relatively easy way to locate and fix errors, which will in turn decrease the necessity to fix a program after it is released for common use. The backdrop for this paper is the Spaceport Command and Control System (SCCS) Simulation Computer Software Configuration Item (CSCI), a project whose goal is to simulate a launch using simulated models of the ground systems and the connections between them and the control room. The simulations will be used for training and to ensure that all possible outcomes and complications are prepared for before the actual launch day. The code being tested is the Programmable Logic Controller Interface (PLCIF) code, the component responsible for transferring the information from the models to the model Programmable Logic Controllers (PLCs), basic computers that are used for very simple tasks.

Optimization of Wind Farm Layout in Complex Terrain

DEFF Research Database (Denmark)

Xu, Chang; Yang, Jianchuan; Li, Chenqi

2013-01-01

Microscopic site selection for wind farms in complex terrain is a technological difficulty in the development of onshore wind farms. This paper presented a method for optimizing wind farm layout in complex terrain. This method employed Lissaman and Jensen wake models, took wind velocity distribut......Microscopic site selection for wind farms in complex terrain is a technological difficulty in the development of onshore wind farms. This paper presented a method for optimizing wind farm layout in complex terrain. This method employed Lissaman and Jensen wake models, took wind velocity...... are subject to boundary conditions and minimum distance conditions. The improved genetic algorithm (GA) for real number coding was used to search the optimal result. Then the optimized result was compared to the result from the experienced layout method. Results show the advantages of the present method...

Compaction-Based Deformable Terrain Model as an Interface for Real-Time Vehicle Dynamics Simulations

Science.gov (United States)

2013-04-16

N.Y. [20] Wulfsohn, D., and Upadhyaya, S. K., 1992, "Prediction of traction and soil compaction using three-dimensional soil- tyre contact profile," Journal of Terramechanics, 29(6), pp. 541-564. ...the relative speedup of utilizing GPUs for computational acceleration. INTRODUCTION In order to enable off- road vehicle dynamics analysis...ANSI Std Z39-18 Page 2 of 8 Figure 2. Tire geometry used to determine collision points with the terrain In the context of off- road vehicle

Generating color terrain images in an emergency response system

International Nuclear Information System (INIS)

Belles, R.D.

1985-08-01

The Atmospheric Release Advisory Capability (ARAC) provides real-time assessments of the consequences resulting from an atmospheric release of radioactive material. In support of this operation, a system has been created which integrates numerical models, data acquisition systems, data analysis techniques, and professional staff. Of particular importance is the rapid generation of graphical images of the terrain surface in the vicinity of the accident site. A terrain data base and an associated acquisition system have been developed that provide the required terrain data. This data is then used as input to a collection of graphics programs which create and display realistic color images of the terrain. The graphics system currently has the capability of generating color shaded relief images from both overhead and perspective viewpoints within minutes. These images serve to quickly familiarize ARAC assessors with the terrain near the release location, and thus permit them to make better informed decisions in modeling the behavior of the released material. 7 refs., 8 figs

Productive uncertainty. Notes on Terrain Vague

Directory of Open Access Journals (Sweden)

Francesco Marullo

2014-12-01

Full Text Available Terrain vague is usually synonym for a place exceeding the traditional categories of the city. Juxtaposing entropy to definite zones of containment, abandonment and emptiness to consolidated urban fabric, ceaseless transformation to historical stratification, informality and illegal activities to controlled jurisdictions, the terrain vague acts a sort of ruin, where the city is at the point of both being forgotten and disclosing its imminent future, eluding any of its regular uses and functioning mechanisms.

Analysis of geologic terrain models for determination of optimum SAR sensor configuration and optimum information extraction for exploration of global non-renewable resources. Pilot study: Arkansas Remote Sensing Laboratory, part 1, part 2, and part 3

Science.gov (United States)

Kaupp, V. H.; Macdonald, H. C.; Waite, W. P.; Stiles, J. A.; Frost, F. S.; Shanmugam, K. S.; Smith, S. A.; Narayanan, V.; Holtzman, J. C. (Principal Investigator)

1982-01-01

Computer-generated radar simulations and mathematical geologic terrain models were used to establish the optimum radar sensor operating parameters for geologic research. An initial set of mathematical geologic terrain models was created for three basic landforms and families of simulated radar images were prepared from these models for numerous interacting sensor, platform, and terrain variables. The tradeoffs between the various sensor parameters and the quantity and quality of the extractable geologic data were investigated as well as the development of automated techniques of digital SAR image analysis. Initial work on a texture analysis of SEASAT SAR imagery is reported. Computer-generated radar simulations are shown for combinations of two geologic models and three SAR angles of incidence.

TERRAIN, BERKS COUNTY, USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, PIERCE, COUNTY, USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, DARKE COUNTY, OH

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, RICE COUNTY, MN

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, JONES COUNTY, IA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, Norfolk County, Massachusetts

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, JEFFERSON COUNTY, USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, WRIGHT COUNTY, IA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, RANKIN COUNTY, MS

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, Pierce County, WA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, MITCHELL COUNTY, IA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, DAWSON COUNTY, NE

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, BARNSTABLE COUNTY, MASSACHUSETTS

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, FRANKLIN COUNTY, IA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, CLALLAM COUNTY, WASHINGTON

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, HOWARD COUNTY, IA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, NEWTON COUNTY, GA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describe the digital topographical data that were used to create...

TERRAIN, PIKE COUNTY, MS

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, Lincoln County, AR

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, KENDALL COUNTY, TEXAS

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, LEON COUNTY, TEXAS

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, SNOHOMISH COUNTY, WASHINGTON

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, TRAVIS COUNTY, TEXAS

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, Bennington County, Vermont

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, Northampton COUNTY, USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that were used to create...

TERRAIN, POTTER COUNTY, USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that were used to create...

TERRAIN, UNION PARISH, LOUSIANA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, KITSAP COUNTY, WASHINGTON

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, WAYNE COUNTY, TENNESSEE

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, TROUSDALE COUNTY, TENNESSEE

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

Using contraband simulators for portal metal detector testing

Energy Technology Data Exchange (ETDEWEB)

Murray, D.W.

1992-08-01

Because contraband materials or items are either too dangerous or too expensive, contraband simulators have been widely used to test contraband detection equipment. Very realistic bomb simulators have been used to test x-ray scanners, and common radioactive sources have been used successfully to test the operation of special nuclear material (SNM) radiation detectors. The simulators used to test early metal detectors were also reasonably successful; however, these simulators were rapidly outdated by the introduction of modern active field metal detectors. This paper describes some of the earlier attempts to develop metal detector test simulators. A successful highly enriched uranium (HEU) simulator for metal detector testing is described that has duplicated all the characteristics modern equipment is capable of detecting. The paper also describes the development needed to produce handgun simulators that could be used effectively for metal detector performance testing.

Using contraband simulators for portal metal detector testing

Energy Technology Data Exchange (ETDEWEB)

Murray, D.W.

1992-01-01

Because contraband materials or items are either too dangerous or too expensive, contraband simulators have been widely used to test contraband detection equipment. Very realistic bomb simulators have been used to test x-ray scanners, and common radioactive sources have been used successfully to test the operation of special nuclear material (SNM) radiation detectors. The simulators used to test early metal detectors were also reasonably successful; however, these simulators were rapidly outdated by the introduction of modern active field metal detectors. This paper describes some of the earlier attempts to develop metal detector test simulators. A successful highly enriched uranium (HEU) simulator for metal detector testing is described that has duplicated all the characteristics modern equipment is capable of detecting. The paper also describes the development needed to produce handgun simulators that could be used effectively for metal detector performance testing.

Using sport psychology in simulator testing

International Nuclear Information System (INIS)

Primeau, T.; Chandler, K.

2007-01-01

The paper will cover the methods of simulator testing at Bruce Power and the recent trial of using a sport psychology consultant to help candidates deal with the mental, physiological and emotional responses to simulator examinations. Previous research has shown that mental skills training can enhance the performance of both cognitive and physical skills. As such, it was hypothesized that a structured mental skills program would assist candidates in achieving optimal performance during simulator testing. The paper will be written as a descriptive piece. The paper will offer insight into the benefits of using mental skills training in preparation for simulator testing and the drawbacks as experienced by the Authorized Nuclear Operator (ANO). (author)

Body shape helps legged robots climb and turn in complex 3-D terrains

Science.gov (United States)

Han, Yuanfeng; Wang, Zheliang; Li, Chen

Analogous to streamlined shapes that reduce drag in fluids, insects' ellipsoid-like rounded body shapes were recently discovered to be ``terradynamically streamlined'' and enhance locomotion in cluttered terrain by facilitating body rolling. Here, we hypothesize that there exist more terradynamic shapes that facilitate other modes of locomotion like climbing and turning in complex 3-D terrains by facilitating body pitching and yawing. To test our hypothesis, we modified the body shape of a legged robot by adding an elliptical and a rectangular shell and tested how it negotiated with circular and square vertical pillars. With a rectangular shell the robot always pitched against square pillars in an attempt to climb, whereas with an elliptical shell it always yawed and turned away from circular pillars given a small initial lateral displacement. Square / circular pillars facilitated pitching / yawing, respectively. To begin to reveal the contact physics, we developed a locomotion energy landscape model. Our model revealed that potential energy barriers to transition from pitching to yawing are high for angular locomotor and obstacle shapes (rectangular / square) but vanish for rounded shapes (elliptical / circular). Our study supports the plausibility of locomotion energy landscapes for understanding the rich locomotor transitions in complex 3-D terrains.

WRF modeling of PM2.5 remediation by SALSCS and its clean air flow over Beijing terrain.

Science.gov (United States)

Cao, Qingfeng; Shen, Lian; Chen, Sheng-Chieh; Pui, David Y H

2018-06-01

Atmospheric simulations were carried out over the terrain of entire Beijing, China, to investigate the effectiveness of an air-pollution cleaning system named Solar-Assisted Large-Scale Cleaning System (SALSCS) for PM 2.5 mitigation by using the Weather Research and Forecasting (WRF) model. SALSCS was proposed to utilize solar energy to generate airflow therefrom the airborne particulate pollution of atmosphere was separated by filtration elements. Our model used a derived tendency term in the potential temperature equation to simulate the buoyancy effect of SALSCS created with solar radiation on its nearby atmosphere. PM 2.5 pollutant and SALSCS clean air were simulated in the model domain by passive tracer scalars. Simulation conditions with two system flow rates of 2.64 × 10 5  m 3 /s and 3.80 × 10 5  m 3 /s were tested for seven air pollution episodes of Beijing during the winters of 2015-2017. The numerical results showed that with eight SALSCSs installed along the 6 th Ring Road of the city, 11.2% and 14.6% of PM 2.5 concentrations were reduced under the two flow-rate simulation conditions, respectively. Copyright © 2018 Elsevier B.V. All rights reserved.

Slip estimation methods for proprioceptive terrain classification using tracked mobile robots

CSIR Research Space (South Africa)

Masha, Ditebogo F

2017-11-01

Full Text Available Recent work has shown that proprioceptive measurements such as terrain slip can be used for terrain classification. This paper investigates the suitability of four simple slip estimation methods for differentiating between indoor and outdoor terrain...

Interactive Editing of GigaSample Terrain Fields

KAUST Repository

Treib, Marc

2012-05-01

Previous terrain rendering approaches have addressed the aspect of data compression and fast decoding for rendering, but applications where the terrain is repeatedly modified and needs to be buffered on disk have not been considered so far. Such applications require both decoding and encoding to be faster than disk transfer. We present a novel approach for editing gigasample terrain fields at interactive rates and high quality. To achieve high decoding and encoding throughput, we employ a compression scheme for height and pixel maps based on a sparse wavelet representation. On recent GPUs it can encode and decode up to 270 and 730 MPix/s of color data, respectively, at compression rates and quality superior to JPEG, and it achieves more than twice these rates for lossless height field compression. The construction and rendering of a height field triangulation is avoided by using GPU ray-casting directly on the regular grid underlying the compression scheme. We show the efficiency of our method for interactive editing and continuous level-of-detail rendering of terrain fields comprised of several hundreds of gigasamples. © 2012 The Author(s).

Real-time maritime scene simulation for ladar sensors

Science.gov (United States)

Christie, Chad L.; Gouthas, Efthimios; Swierkowski, Leszek; Williams, Owen M.

2011-06-01

Continuing interest exists in the development of cost-effective synthetic environments for testing Laser Detection and Ranging (ladar) sensors. In this paper we describe a PC-based system for real-time ladar scene simulation of ships and small boats in a dynamic maritime environment. In particular, we describe the techniques employed to generate range imagery accompanied by passive radiance imagery. Our ladar scene generation system is an evolutionary extension of the VIRSuite infrared scene simulation program and includes all previous features such as ocean wave simulation, the physically-realistic representation of boat and ship dynamics, wake generation and simulation of whitecaps, spray, wake trails and foam. A terrain simulation extension is also under development. In this paper we outline the development, capabilities and limitations of the VIRSuite extensions.

Gravity Terrain Effect of the Seafloor Topography in Taiwan

Directory of Open Access Journals (Sweden)

Lun-Tao Tong Tai-Rong Guo

2007-01-01

Full Text Available Gravity terrain correction is used to compensate for the gravitational effects of the topography residual to the Bouguer plate. The seafloor topography off the eastern offshore of Taiwan is extremely rugged, and the depth of the sea bottom could be greater than 5000 m. In order to evaluate the terrain effect caused by the seafloor topography, a modern computer algorithm is used to calculate the terrain correction based on the digital elevation model (DEM.

Estimating Slopes In Images Of Terrain By Use Of BRDF

Science.gov (United States)

Scholl, Marija S.

1995-01-01

Proposed method of estimating slopes of terrain features based on use of bidirectional reflectivity distribution function (BRDF) in analyzing aerial photographs, satellite video images, or other images produced by remote sensors. Estimated slopes integrated along horizontal coordinates to obtain estimated heights; generating three-dimensional terrain maps. Method does not require coregistration of terrain features in pairs of images acquired from slightly different perspectives nor requires Sun or other source of illumination to be low in sky over terrain of interest. On contrary, best when Sun is high. Works at almost all combinations of illumination and viewing angles.

Gas-liquid two-phase flow behavior in terrain-inclined pipelines for gathering transport system of wet natural gas

DEFF Research Database (Denmark)

Yang, Yan; Li, Jingbo; Wang, Shuli

2018-01-01

The Volume of Fluid method and Re-Normalisation Group (RNG) k-ε turbulence model were employed to predict the gas-liquid two-phase flow in a terrain-inclined pipeline with deposited liquids. The simulation was carried out in a 22.5 m terrain-inclined pipeline with a 150 mm internal diameter...... on the liquid level under the suction force which caused by the negative pressure around the elbow, and then it touched to the top of the pipe. When the liquid blocked the pipe, the pressure drop between the upstream and downstream of the elbow increased with the increase of the gas velocity. At larger gas...

Terrain aided navigation for autonomous underwater vehicles with coarse maps

International Nuclear Information System (INIS)

Zhou, Ling; Cheng, Xianghong; Zhu, Yixian

2016-01-01

Terrain aided navigation (TAN) is a form of geophysical localization technique for autonomous underwater vehicles (AUVs) operating in GPS-denied environments. TAN performance on sensor-rich AUVs has been evaluated in sea trials. However, many challenges remain before TAN can be successfully implemented on sensor-limited AUVs, especially with coarse maps. To improve TAN performance over coarse maps, a Gaussian process (GP) is proposed for the modeling of bathymetric terrain and integrated into the particle filter (GP-PF). GP is applied to provide not only the bathymetric value prediction through learning a set of bathymetric data from coarse maps but also the variance of the prediction. As a measurement update, calculated on bathymetric deviation is performed through the PF to obtain absolute and bounded positioning accuracy. Through the analysis of TAN performance on experimental data for two different terrains with map resolutions of 10–50 m, both the ability of the proposed model to represent the actual bathymetric terrain with accuracy and the effect of the GP-PF for TAN on sensor-limited systems in suited terrain are demonstrated. The experiment results further verify that there is an inverse relationship between the coarseness of the map and the overall TAN accuracy in rough terrains, but there is hardly any relationship between them in relatively flat terrains. (paper)

Molecular dynamics simulation of impact test

International Nuclear Information System (INIS)

Akahoshi, Y.; Schmauder, S.; Ludwig, M.

1998-01-01

This paper describes an impact test by molecular dynamics (MD) simulation to evaluate embrittlement of bcc Fe at different temperatures. A new impact test model is developed for MD simulation. The typical fracture behaviors show transition from brittle to ductile fracture, and a history of the impact loads also demonstrates its transition. We conclude that the impact test by MD could be feasible. (orig.)

Molecular dynamics simulation of impact test

Energy Technology Data Exchange (ETDEWEB)

Akahoshi, Y. [Kyushu Inst. of Tech., Kitakyushu, Fukuoka (Japan); Schmauder, S.; Ludwig, M. [Stuttgart Univ. (Germany). Staatliche Materialpruefungsanstalt

1998-11-01

This paper describes an impact test by molecular dynamics (MD) simulation to evaluate embrittlement of bcc Fe at different temperatures. A new impact test model is developed for MD simulation. The typical fracture behaviors show transition from brittle to ductile fracture, and a history of the impact loads also demonstrates its transition. We conclude that the impact test by MD could be feasible. (orig.)

Evaluating terrain based criteria for snow avalanche exposure ratings using GIS

Science.gov (United States)

Delparte, Donna; Jamieson, Bruce; Waters, Nigel

2010-05-01

Snow avalanche terrain in backcountry regions of Canada is increasingly being assessed based upon the Avalanche Terrain Exposure Scale (ATES). ATES is a terrain based classification introduced in 2004 by Parks Canada to identify "simple", "challenging" and "complex" backcountry areas. The ATES rating system has been applied to well over 200 backcountry routes, has been used in guidebooks, trailhead signs and maps and is part of the trip planning component of the AVALUATOR™, a simple decision-support tool for backcountry users. Geographic Information Systems (GIS) offers a means to model and visualize terrain based criteria through the use of digital elevation model (DEM) and land cover data. Primary topographic variables such as slope, aspect and curvature are easily derived from a DEM and are compatible with the equivalent evaluation criteria in ATES. Other components of the ATES classification are difficult to extract from a DEM as they are not strictly terrain based. An overview is provided of the terrain variables that can be generated from DEM and land cover data; criteria from ATES which are not clearly terrain based are identified for further study or revision. The second component of this investigation was the development of an algorithm for inputting suitable ATES criteria into a GIS, thereby mimicking the process avalanche experts use when applying the ATES classification to snow avalanche terrain. GIS based classifications were compared to existing expert assessments for validity. The advantage of automating the ATES classification process through GIS is to assist avalanche experts with categorizing and mapping remote backcountry terrain.

Constraining the Surface Energy Balance of Snow in Complex Terrain

Science.gov (United States)

Lapo, Karl E.

values and coupled land-atmosphere models have difficulty representing these processes. We developed a new method analyzing turbulent fluxes at the land surface that relies on using the observed surface temperature, which we called the offline turbulence method. We used this method to test a number of stability schemes as they are implemented within land models. Stability schemes can cause small biases in the simulated sensible heat flux, but these are caused by compensating errors, as no single method was able to accurately reproduce the observed distribution of the sensible heat flux. We described how these turbulence schemes perform within different turbulence regimes, particularly noting the difficulty representing turbulence during conditions with faster wind speeds and the transition between weak and strong wind turbulence regimes. Heterogeneity in the horizontal distribution of surface temperature associated with different land surface types likely explains some of the missing physics within land models and is manifested as counter-gradient fluxes in observations. The coupling of land and atmospheric models needs further attention, as we highlight processes that are missing. Expanding on the utility of surface temperature, Ts, in model evaluations, we demonstrated the utility of using surface temperature in snow models evaluations. Ts is the diagnostic variable of the modeled surface energy balance within physically-based models and is an ideal supplement to traditional evaluation techniques. We demonstrated how modeling decisions affect Ts, specifically testing the impact of vertical layer structure, thermal conductivity, and stability corrections in addition to the effect of uncertainty in forcing data on simulated Ts. The internal modeling decisions had minimal impacts relative to uncertainty in the forcing data. Uncertainty in downwelling longwave was found to have the largest impact on simulated Ts. Using Ts, we demonstrated how various errors in the forcing

Automatic terrain modeling using transfinite element analysis

KAUST Repository

Collier, Nathan

2010-05-31

An automatic procedure for modeling terrain is developed based on L2 projection-based interpolation of discrete terrain data onto transfinite function spaces. The function space is refined automatically by the use of image processing techniques to detect regions of high error and the flexibility of the transfinite interpolation to add degrees of freedom to these areas. Examples are shown of a section of the Palo Duro Canyon in northern Texas.

Online 3D terrain visualisation using Unity 3D game engine: A comparison of different contour intervals terrain data draped with UAV images

Science.gov (United States)

Hafiz Mahayudin, Mohd; Che Mat, Ruzinoor

2016-06-01

The main objective of this paper is to discuss on the effectiveness of visualising terrain draped with Unmanned Aerial Vehicle (UAV) images generated from different contour intervals using Unity 3D game engine in online environment. The study area that was tested in this project was oil palm plantation at Sintok, Kedah. The contour data used for this study are divided into three different intervals which are 1m, 3m and 5m. ArcGIS software were used to clip the contour data and also UAV images data to be similar size for the overlaying process. The Unity 3D game engine was used as the main platform for developing the system due to its capabilities which can be launch in different platform. The clipped contour data and UAV images data were process and exported into the web format using Unity 3D. Then process continue by publishing it into the web server for comparing the effectiveness of different 3D terrain data (contour data) draped with UAV images. The effectiveness is compared based on the data size, loading time (office and out-of-office hours), response time, visualisation quality, and frame per second (fps). The results were suggest which contour interval is better for developing an effective online 3D terrain visualisation draped with UAV images using Unity 3D game engine. It therefore benefits decision maker and planner related to this field decide on which contour is applicable for their task.

A Research on Wind Farm Micro-sitting Optimization in Complex Terrain

DEFF Research Database (Denmark)

Xu, Chang; Yang, Jianchuan; Li, Chenqi

2013-01-01

Wind farm layout optimization in complex terrain is a pretty difficult issue for onshore wind farm. In this article, a novel optimization method is proposed to optimize the layout for wind farms in complex terrain. This method utilized Lissaman and Jensen wake models for taking the terrain height...... that the CPSO method has a higher optimal value, and could be used to optimize the actual wind farm micro-sitting engineering projects.......Wind farm layout optimization in complex terrain is a pretty difficult issue for onshore wind farm. In this article, a novel optimization method is proposed to optimize the layout for wind farms in complex terrain. This method utilized Lissaman and Jensen wake models for taking the terrain height...... turbines’ park coordinates which subject to the boundary and minimum distance conditions between two wind turbines. A Cross Particle Swarm Optimization (CPSO) method is developed and applied to optimize the layout for a certain wind farm case. Compared with the uniform and experience method, results show...

Design and Test of Advanced Thermal Simulators for an Alkali Metal-Cooled Reactor Simulator

Science.gov (United States)

Garber, Anne E.; Dickens, Ricky E.

2011-01-01

The Early Flight Fission Test Facility (EFF-TF) at NASA Marshall Space Flight Center (MSFC) has as one of its primary missions the development and testing of fission reactor simulators for space applications. A key component in these simulated reactors is the thermal simulator, designed to closely mimic the form and function of a nuclear fuel pin using electric heating. Continuing effort has been made to design simple, robust, inexpensive thermal simulators that closely match the steady-state and transient performance of a nuclear fuel pin. A series of these simulators have been designed, developed, fabricated and tested individually and in a number of simulated reactor systems at the EFF-TF. The purpose of the thermal simulators developed under the Fission Surface Power (FSP) task is to ensure that non-nuclear testing can be performed at sufficiently high fidelity to allow a cost-effective qualification and acceptance strategy to be used. Prototype thermal simulator design is founded on the baseline Fission Surface Power reactor design. Recent efforts have been focused on the design, fabrication and test of a prototype thermal simulator appropriate for use in the Technology Demonstration Unit (TDU). While designing the thermal simulators described in this paper, effort were made to improve the axial power profile matching of the thermal simulators. Simultaneously, a search was conducted for graphite materials with higher resistivities than had been employed in the past. The combination of these two efforts resulted in the creation of thermal simulators with power capacities of 2300-3300 W per unit. Six of these elements were installed in a simulated core and tested in the alkali metal-cooled Fission Surface Power Primary Test Circuit (FSP-PTC) at a variety of liquid metal flow rates and temperatures. This paper documents the design of the thermal simulators, test program, and test results.

Modeling soil organic carbon stock after 10 years of cover crops in Mediterranean vineyards: improving ANN prediction by digital terrain analysis.

Science.gov (United States)

Lo Papa, Giuseppe; Novara, Agata; Santoro, Antonino; Gristina, Luciano

2014-05-01

Estimate changes in soil organic carbon (SOC) stock after Agro Environment Measures adoption are strategically for national and regional scale. Uncertainty in estimates also represents a very important parameter in terms of evaluation of the exact costs and agro environment payments to farmers. In this study we modeled the variation of SOC stock after 10-year cover crop adoption in a vine growing area of South-Eastern Sicily. A paired-site approach was chosen to study the difference in SOC stocks. A total 100 paired sites (i.e. two adjacent plots) were chosen and three soil samples (Ap soil horizons, circa 0-30 cm depth) were collected in each plot to obtain a mean value of organic carbon concentration for each plot. The variation of soil organic carbon (SOCv) for each plot was calculated by differences between concentrations of the plot subjected to cover crops (SOC10) and the relative plot subjected to traditional agronomic practices (SOC0). The feasibility of using artificial neural networks as a method to predict soil organic carbon stock variation and the contribution of digital terrain analysis to improve the prediction were tested. We randomly subdivided the experimental values of SOC-stock difference in 80 learning samples and 20 test samples for model validation. SOCv was strongly correlated to the SOC0 concentration. Model validation using only SOCv as unique covariate showed a training and test perfection of 0.724 and 0.871 respectively. We hypothesized that terrain-driven hydrological flow patterns, mass-movement and local micro-climatic factors could be responsible processes contributing for SOC redistributions, thus affecting soil carbon stock in time. Terrain attributes were derived by digital terrain analysis from the 10 m DEM of the study area. A total of 37 terrain attributes were calculated and submitted to statistical feature selection. The Chi-square ranking indicated only 4 significant covariates among the terrain attributes (slope height

Test/score/report: Simulation techniques for automating the test process

Science.gov (United States)

Hageman, Barbara H.; Sigman, Clayton B.; Koslosky, John T.

1994-01-01

A Test/Score/Report capability is currently being developed for the Transportable Payload Operations Control Center (TPOCC) Advanced Spacecraft Simulator (TASS) system which will automate testing of the Goddard Space Flight Center (GSFC) Payload Operations Control Center (POCC) and Mission Operations Center (MOC) software in three areas: telemetry decommutation, spacecraft command processing, and spacecraft memory load and dump processing. Automated computer control of the acceptance test process is one of the primary goals of a test team. With the proper simulation tools and user interface, the task of acceptance testing, regression testing, and repeatability of specific test procedures of a ground data system can be a simpler task. Ideally, the goal for complete automation would be to plug the operational deliverable into the simulator, press the start button, execute the test procedure, accumulate and analyze the data, score the results, and report the results to the test team along with a go/no recommendation to the test team. In practice, this may not be possible because of inadequate test tools, pressures of schedules, limited resources, etc. Most tests are accomplished using a certain degree of automation and test procedures that are labor intensive. This paper discusses some simulation techniques that can improve the automation of the test process. The TASS system tests the POCC/MOC software and provides a score based on the test results. The TASS system displays statistics on the success of the POCC/MOC system processing in each of the three areas as well as event messages pertaining to the Test/Score/Report processing. The TASS system also provides formatted reports documenting each step performed during the tests and the results of each step. A prototype of the Test/Score/Report capability is available and currently being used to test some POCC/MOC software deliveries. When this capability is fully operational it should greatly reduce the time necessary

Optimization of wind farm micro-siting for complex terrain using greedy algorithm

International Nuclear Information System (INIS)

Song, M.X.; Chen, K.; He, Z.Y.; Zhang, X.

2014-01-01

An optimization approach based on greedy algorithm for optimization of wind farm micro-siting is presented. The key of optimizing wind farm micro-siting is the fast and accurate evaluation of the wake flow interactions of wind turbines. The virtual particle model is employed for wake flow simulation of wind turbines, which makes the present method applicable for non-uniform flow fields on complex terrains. In previous bionic optimization method, within each step of the optimization process, only the power output of the turbine that is being located or relocated is considered. To aim at the overall power output of the wind farm comprehensively, a dependent region technique is introduced to improve the estimation of power output during the optimization procedure. With the technique, the wake flow influences can be reduced more efficiently during the optimization procedure. During the optimization process, the turbine that is being added will avoid being affected other turbines, and avoid affecting other turbine in the meantime. The results from the numerical calculations demonstrate that the present method is effective for wind farm micro-siting on complex terrain, and it produces better solutions in less time than the previous bionic method. - Highlights: • Greedy algorithm is applied to wind farm micro-siting problem. • The present method is effective for optimization on complex terrains. • Dependent region is suggested to improve the evaluation of wake influences. • The present method has better performance than the bionic method

Real time simulator for material testing reactor

Energy Technology Data Exchange (ETDEWEB)

Takemoto, Noriyuki; Imaizumi, Tomomi; Izumo, Hironobu; Hori, Naohiko; Suzuki, Masahide [Japan Atomic Energy Agency, Oarai Research and Development Center, Oarai, Ibaraki (Japan); Ishitsuka, Tatsuo; Tamura, Kazuo [ITOCHU Techno-Solutions Corp., Tokyo (Japan)

2012-03-15

Japan Atomic Energy Agency (JAEA) is now developing a real time simulator for a material testing reactor based on Japan Materials Testing Reactor (JMTR). The simulator treats reactor core system, primary and secondary cooling system, electricity system and irradiation facility systems. Possible simulations are normal reactor operation, unusual transient operation and accidental operation. The developed simulator also contains tool to revise/add facility in it for the future development. (author)

Real time simulator for material testing reactor

International Nuclear Information System (INIS)

Takemoto, Noriyuki; Imaizumi, Tomomi; Izumo, Hironobu; Hori, Naohiko; Suzuki, Masahide; Ishitsuka, Tatsuo; Tamura, Kazuo

2012-01-01

Japan Atomic Energy Agency (JAEA) is now developing a real time simulator for a material testing reactor based on Japan Materials Testing Reactor (JMTR). The simulator treats reactor core system, primary and secondary cooling system, electricity system and irradiation facility systems. Possible simulations are normal reactor operation, unusual transient operation and accidental operation. The developed simulator also contains tool to revise/add facility in it for the future development. (author)

Testing cooperative systems with the MARS simulator

NARCIS (Netherlands)

Netten, B.D.; Wedemeijer, H.

2010-01-01

The complexity of cooperative systems makes the use of high fidelity simulation essential in the development and testing of cooperative applications and their interactions with other cooperative systems. In SAFESPOT a simulator test bench is setup to test the safety margin applications running on

Ground testing and simulation. II - Aerodynamic testing and simulation: Saving lives, time, and money

Science.gov (United States)

Dayman, B., Jr.; Fiore, A. W.

1974-01-01

The present work discusses in general terms the various kinds of ground facilities, in particular, wind tunnels, which support aerodynamic testing. Since not all flight parameters can be simulated simultaneously, an important problem consists in matching parameters. It is pointed out that there is a lack of wind tunnels for a complete Reynolds-number simulation. Using a computer to simulate flow fields can result in considerable reduction of wind-tunnel hours required to develop a given flight vehicle.

Comparing mixing-length models of the diabatic wind profile over homogeneous terrain

DEFF Research Database (Denmark)

Pena Diaz, Alfredo; Gryning, Sven-Erik; Hasager, Charlotte Bay

2010-01-01

Models of the diabatic wind profile over homogeneous terrain for the entire atmospheric boundary layer are developed using mixing-length theory and are compared to wind speed observations up to 300 m at the National Test Station for Wind Turbines at Høvsøre, Denmark. The measurements are performe...

Terrain Adaptive Reconfiguration of Mobility

Data.gov (United States)

National Aeronautics and Space Administration — Develop an algorithm (and software) to automatically adapt a reconfigurable robot to different types of terrains for improved mobility, that compared to SOA:...

For wind turbines in complex terrain, the devil is in the detail

Science.gov (United States)

Lange, Julia; Mann, Jakob; Berg, Jacob; Parvu, Dan; Kilpatrick, Ryan; Costache, Adrian; Chowdhury, Jubayer; Siddiqui, Kamran; Hangan, Horia

2017-09-01

The cost of energy produced by onshore wind turbines is among the lowest available; however, onshore wind turbines are often positioned in a complex terrain, where the wind resources and wind conditions are quite uncertain due to the surrounding topography and/or vegetation. In this study, we use a scale model in a three-dimensional wind-testing chamber to show how minor changes in the terrain can result in significant differences in the flow at turbine height. These differences affect not only the power performance but also the life-time and maintenance costs of wind turbines, and hence, the economy and feasibility of wind turbine projects. We find that the mean wind, wind shear and turbulence level are extremely sensitive to the exact details of the terrain: a small modification of the edge of our scale model, results in a reduction of the estimated annual energy production by at least 50% and an increase in the turbulence level by a factor of five in the worst-case scenario with the most unfavorable wind direction. Wind farm developers should be aware that near escarpments destructive flows can occur and their extent is uncertain thus warranting on-site field measurements.

A neural network model for estimating soil phosphorus using terrain analysis

Directory of Open Access Journals (Sweden)

Ali Keshavarzi

2015-12-01

Full Text Available Artificial neural network (ANN model was developed and tested for estimating soil phosphorus (P in Kouhin watershed area (1000 ha, Qazvin province, Iran using terrain analysis. Based on the soil distribution correlation, vegetation growth pattern across the topographically heterogeneous landscape, the topographic and vegetation attributes were used in addition to pedologic information for the development of ANN model in area for estimating of soil phosphorus. Totally, 85 samples were collected and tested for phosphorus contents and corresponding attributes were estimated by the digital elevation model (DEM. In order to develop the pedo-transfer functions, data linearity was checked, correlated and 80% was used for modeling and ANN was tested using 20% of collected data. Results indicate that 68% of the variation in soil phosphorus could be explained by elevation and Band 1 data and significant correlation was observed between input variables and phosphorus contents. There was a significant correlation between soil P and terrain attributes which can be used to derive the pedo-transfer function for soil P estimation to manage nutrient deficiency. Results showed that P values can be calculated more accurately with the ANN-based pedo-transfer function with the input topographic variables along with the Band 1.

Simulation and material testing of jet engines

International Nuclear Information System (INIS)

Tariq, M.M.

2006-01-01

The NASA software engine simulator version U 1.7a beta has been used for simulation and material testing of jet engines. Specifications of Modem Jet Engines are stated, and then engine simulator is applied on these specifications. This simulator can simulate turbojet, afterburner, turbofan and ram jet. The material of many components of engine may be varied. Conventional and advanced materials for jet engines can be simulated and tested. These materials can be actively cooled to increase the operating temperature limit. As soon as temperature of any engine component exceeds the temperature limit of material, a warning message flashes across screen. Temperature Limits Exceeded. This flashing message remainst here until necessaryc hangesa re carried out in engine operationp rocedure. Selection Criteria of Engines is stated for piston prop, turboprop, turbofan, turbojet, and turbojet with afterburner and Ramjet. Several standard engines are modeled in Engine Simulator. These engines can. be compared by several engineering specifications. The design, modeling, simulation and testing of engines helps to better understand different types of materials used in jet engines. (author)

BWR Full Integral Simulation Test (FIST). Phase I test results

International Nuclear Information System (INIS)

Hwang, W.S.; Alamgir, M.; Sutherland, W.A.

1984-09-01

A new full height BWR system simulator has been built under the Full-Integral-Simulation-Test (FIST) program to investigate the system responses to various transients. The test program consists of two test phases. This report provides a summary, discussions, highlights and conclusions of the FIST Phase I tests. Eight matrix tests were conducted in the FIST Phase I. These tests have investigated the large break, small break and steamline break LOCA's, as well as natural circulation and power transients. Results and governing phenomena of each test have been evaluated and discussed in detail in this report. One of the FIST program objectives is to assess the TRAC code by comparisons with test data. Two pretest predictions made with TRACB02 are presented and compared with test data in this report

Convective boundary layer heights over mountainous terrain - A review of concepts -

Science.gov (United States)

De Wekker, Stephan; Kossmann, Meinolf

2015-12-01

Mountainous terrain exerts an important influence on the Earth's atmosphere and affects atmospheric transport and mixing at a wide range of temporal and spatial scales. The vertical scale of this transport and mixing is determined by the height of the atmospheric boundary layer, which is therefore an important parameter in air pollution studies, weather forecasting, climate modeling, and many other applications. It is recognized that the spatio-temporal structure of the daytime convective boundary layer (CBL) height is strongly modified and more complex in hilly and mountainous terrain compared to flat terrain. While the CBL over flat terrain is mostly dominated by turbulent convection, advection from multi-scale thermally driven flows plays an important role for the CBL evolution over mountainous terrain. However, detailed observations of the CBL structure and understanding of the underlying processes are still limited. Characteristics of CBL heights in mountainous terrain are reviewed for dry, convective conditions. CBLs in valleys and basins, where hazardous accumulation of pollutants is of particular concern, are relatively well-understood compared to CBLs over slopes, ridges, or mountain peaks. Interests in the initiation of shallow and deep convection, and of budgets and long-range transport of air pollutants and trace gases, have triggered some recent studies on terrain induced exchange processes between the CBL and the overlying atmosphere. These studies have helped to gain more insight into CBL structure over complex mountainous terrain, but also show that the universal definition of CBL height over mountains remains an unresolved issue. The review summarizes the progress that has been made in documenting and understanding spatio-temporal behavior of CBL heights in mountainous terrain and concludes with a discussion of open research questions and opportunities for future research.

Complex terrain influences ecosystem carbon responses to temperature and precipitation

Science.gov (United States)

Reyes, W. M.; Epstein, H. E.; Li, X.; McGlynn, B. L.; Riveros-Iregui, D. A.; Emanuel, R. E.

2017-08-01

Terrestrial ecosystem responses to temperature and precipitation have major implications for the global carbon cycle. Case studies demonstrate that complex terrain, which accounts for more than 50% of Earth's land surface, can affect ecological processes associated with land-atmosphere carbon fluxes. However, no studies have addressed the role of complex terrain in mediating ecophysiological responses of land-atmosphere carbon fluxes to climate variables. We synthesized data from AmeriFlux towers and found that for sites in complex terrain, responses of ecosystem CO2 fluxes to temperature and precipitation are organized according to terrain slope and drainage area, variables associated with water and energy availability. Specifically, we found that for tower sites in complex terrain, mean topographic slope and drainage area surrounding the tower explained between 51% and 78% of site-to-site variation in the response of CO2 fluxes to temperature and precipitation depending on the time scale. We found no such organization among sites in flat terrain, even though their flux responses exhibited similar ranges. These results challenge prevailing conceptual framework in terrestrial ecosystem modeling that assumes that CO2 fluxes derive from vertical soil-plant-climate interactions. We conclude that the terrain in which ecosystems are situated can also have important influences on CO2 responses to temperature and precipitation. This work has implications for about 14% of the total land area of the conterminous U.S. This area is considered topographically complex and contributes to approximately 15% of gross ecosystem carbon production in the conterminous U.S.

VTAC: virtual terrain assisted impact assessment for cyber attacks

Science.gov (United States)

Argauer, Brian J.; Yang, Shanchieh J.

2008-03-01

Overwhelming intrusion alerts have made timely response to network security breaches a difficult task. Correlating alerts to produce a higher level view of intrusion state of a network, thus, becomes an essential element in network defense. This work proposes to analyze correlated or grouped alerts and determine their 'impact' to services and users of the network. A network is modeled as 'virtual terrain' where cyber attacks maneuver. Overlaying correlated attack tracks on virtual terrain exhibits the vulnerabilities exploited by each track and the relationships between them and different network entities. The proposed impact assessment algorithm utilizes the graph-based virtual terrain model and combines assessments of damages caused by the attacks. The combined impact scores allow to identify severely damaged network services and affected users. Several scenarios are examined to demonstrate the uses of the proposed Virtual Terrain Assisted Impact Assessment for Cyber Attacks (VTAC).

Dynamic modeling and mobility analysis of the transforming roving-rolling explorer (TRREx) as it Traverses Rugged Martian Terrain

Science.gov (United States)

Edwin, Lionel E.; Mazzoleni, Andre P.

2016-03-01

All planetary surface exploration missions thus far have employed traditional rovers with a rocker-bogie suspension. These rovers can navigate moderately rough and flat terrain, but are not designed to traverse rugged terrain with steep slopes. The fact is, however, that the most scientifically interesting missions require exploration platforms with capabilities for navigating such types of rugged terrain. This issue motivates the development of new kinds of rovers that take advantage of the latest advances in robotic technologies to traverse rugged terrain efficiently. This work analyzes one such rover concept called the Transforming Roving-Rolling Explorer (TRREx) that is principally aimed at addressing the above issue. Biologically inspired by the way the armadillo curls up into a ball when threatened, and the way the golden wheel spider uses the dynamic advantages of a sphere to roll down hills when escaping danger, the TRREx rover can traverse like a traditional 6-wheeled rover over conventional terrain, but can also transform itself into a sphere, when necessary, to travel down steep inclines, or navigate rough terrain. This paper investigates the mobility of the TRREx when it is in its rolling mode, i.e. when it is a sphere and can steer itself through actuations that shift its center of mass to achieve the desired direction of roll. A mathematical model describing the dynamics of the rover in this spherical configuration is presented, and actuated rolling is demonstrated through computer simulation. Parametric analyzes that investigate the rover's mobility as a function of its design parameters are also presented. This work highlights the contribution of the spherical rolling mode to the enhanced mobility of the TRREx rover and how it could enable challenging surface exploration missions in the future.

Colour based off-road environment and terrain type classification

NARCIS (Netherlands)

Jansen, P.; Mark, W. van der; Heuvel, J.C. van den; Groen, F.C.A.

2005-01-01

Terrain classification is an important problem that still remains to be solved for off-road autonomous robot vehicle guidance. Often, obstacle detection systems are used which cannot distinguish between solid obstacles such as rocks or soft obstacles such as tall patches of grass. Terrain

ATRAN Terrain Sensing Guidance-The Grand-Daddy System

Science.gov (United States)

Koch, Richard F.; Evans, Donald C.

1980-12-01

ATRAN was the pioneer terrain sensing guidance system developed in the 1950 era and deployed in Europe on the Air Force's mobile, ground launched TM-76A MACE cruise missile in the late 1950's and early 1960's. The background, principles and technology are described for this system which was the forerunner of todays modern autonomous standoff terrain sensing guided weapons.

Numerical Simulation Analysis of Seismic of Frame Structure on Hill Terrain

Directory of Open Access Journals (Sweden)

Weng Weisu

2017-01-01

Full Text Available In recent year, Wenchuan,Ya’an,Yushu and other areas in china occur a series of high earthquake, however areas of earthquake is similar as mountainous terrain, building structure of seismic increasingly aroused our concern, and the research that hill topography affected building structure seismic in shallow mountain. The research content mainly includes: through modelling was built by the ANSYS software, the cooperative effects of a ten layer of frame structure- hill system were calculation. First, simple comparative dynamic characteristics analysis of soil - structure interaction and the rigid foundation assumption conditions; Second, put Hill-Soil-Structure Interaction(referred to as HSSI and Soil - Structure - Interaction(referred to as SSI further analysis of the dynamic response, including: including structural modal analysis (vibration mode, cycle, the time history analysis (such as displacement, internal force and acceleration and so on. Through Hill-Soil-Structure Interaction research, taking each factor in consideration, giving structure seismic key technology measures about shallow mountain to provide reference for such structure theory research.

TERRAIN, ALLENDALE COUNTY, SOUTH CAROLINA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, WAKULLA COUNTY, FL, USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, BRADFORD COUNTY, FL, USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, GADSDEN COUNTY, FL, USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, LEVY COUNTY, FL, USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, WOODFORD COUNTY, KENTUCKY USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, TANEY COUNTY, Missouri USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, FRANKLIN PARISH, LA, USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, Catahoula PARISH, LA, USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, RICHLAND PARISH, LA, USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, OVERTON COUNTY, TN, USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, STEWART COUNTY, TN, USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, POWELL COUNTY, KENTUCKY USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, HENRY COUNTY, KENTUCKY USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, BARREN COUNTY, KENTUCKY USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, LOWNDES COUNTY, ALABAMA USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, FRANKLIN COUNTY, ALABAMA USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, HARRISON COUNTY, KENTUCKY USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, LOGAN COUNTY, KENTUCKY USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, WINNESHIEK COUNTY, IOWA, USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, CHEROKEE COUNTY, ALABAMA USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, JEFFERSON COUNTY, ALABAMA USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, POWESHIEK COUNTY, IOWA USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, RANDOLPH COUNTY, ALABAMA USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, ELMORE COUNTY, ALABAMA USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, ANNE ARUNDEL COUNTY, USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, WASHINGTON COUNTY, KENTUCKY USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, WASHINGTON COUNTY, Ohio USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, LAWRENCE COUNTY, Ohio USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, SEBASTIAN COUNTY, AR, USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describe the digital topographical data that were used to create...

TERRAIN, BALLARD COUNTY, KENTUCKY USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, NELSON COUNTY, KENTUCKY USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, EVANGELINE PARISH, LA, USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, HOUSTON COUNTY, TN, USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, JESSAMINE COUNTY, KENTUCKY USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN Submission for CHICKASAW, IA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, TALLAPOOSA COUNTY, ALABAMA USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, MOREHOUSE PARISH, LA, USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, ALLEN COUNTY, KENTUCKY USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, LEWIS COUNTY, Missouri USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, BUFFALO COUNTY, WISCONSIN, USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, MARENGO COUNTY, ALABAMA USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, CLARKE COUNTY, ALABAMA USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, HART COUNTY, KENTUCKY USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, MONROE COUNTY, Michigan USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, WAYNE COUNTY, KENTUCKY USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, MCLEAN COUNTY, KENTUCKY USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, WINSTON COUNTY, ALABAMA USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, CHAMBERS COUNTY, ALABAMA USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, PERRY COUNTY, ALABAMA USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, ESTILL COUNTY, KENTUCKY USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, NATCHITOCHES PARISH, LA, USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, CLINTON COUNTY, KENTUCKY USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, CHILTON COUNTY, ALABAMA USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, GRAYSON COUNTY, KENTUCKY USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, GARRARD COUNTY, KENTUCKY USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, Sedgwick COUNTY, Kansas USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, MACOMB COUNTY, MI, USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, MARSHALL COUNTY, ALABAMA USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

Terrain Data, Caroline COUNTY, USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, SUWANNEE COUNTY, FLORIDA USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, CHOCTAW COUNTY, ALABAMA USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, CARLISLE COUNTY, KENTUCKY USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, SIMPSON COUNTY, KENTUCKY USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, GRAVES COUNTY, KENTUCKY USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, MADISON COUNTY, ALABAMA USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, LAWRENCE COUNTY, ALABAMA USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, MENIFEE COUNTY, KENTUCKY USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, SHELBY COUNTY, ALABAMA USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, Platte County, Missouri USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, SCOTT COUNTY, KENTUCKY USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, FAYETTE COUNTY, KENTUCKY USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, CARTER COUNTY, KENTUCKY USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, SANTA CRUZ COUNTY, AZ

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, MUHLENBERG COUNTY, KENTUCKY USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, CAMPBELL COUNTY, KENTUCKY USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

47 CFR 1.959 - Computation of average terrain elevation.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 1 2010-10-01 2010-10-01 false Computation of average terrain elevation. 1.959 Section 1.959 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL PRACTICE AND PROCEDURE Wireless Radio Services Applications and Proceedings Application Requirements and Procedures § 1.959 Computation of average terrain elevation. Except a...

High-resolution WRF-LES simulations for real episodes: A case study for prealpine terrain

Science.gov (United States)

Hald, Cornelius; Mauder, Matthias; Laux, Patrick; Kunstmann, Harald

2017-04-01

While in most large or regional scale weather and climate models turbulence is parametrized, LES (Large Eddy Simulation) allows for the explicit modeling of turbulent structures in the atmosphere. With the exponential growth in available computing power the technique has become more and more applicable, yet it has mostly been used to model idealized scenarios. It is investigated how well WRF-LES can represent small scale weather patterns. The results are evaluated against different hydrometeorological measurements. We use WRF-LES to model the diurnal cycle for a 48 hour episode in summer over moderately complex terrain in southern Germany. The model setup uses a high resolution digital elevation model, land use and vegetation map. The atmospheric boundary conditions are set by reanalysis data. Schemes for radiation and microphysics and a land-surface model are employed. The biggest challenge in modeling arises from the high horizontal resolution of dx = 30m, since the subgrid-scale model then requires a vertical resolution dz ≈ 10m for optimal results. We observe model instabilities and present solutions like smoothing of the surface input data, careful positioning of the model domain and shortening of the model time step down to a twentieth of a second. Model results are compared to an array of various instruments including eddy covariance stations, LIDAR, RASS, SODAR, weather stations and unmanned aerial vehicles. All instruments are part of the TERENO pre-Alpine area and were employed in the orchestrated measurement campaign ScaleX in July 2015. Examination of the results show reasonable agreement between model and measurements in temperature- and moisture profiles. Modeled wind profiles are highly dependent on the vertical resolution and are in accordance with measurements only at higher wind speeds. A direct comparison of turbulence is made difficult by the purely statistical character of turbulent motions in the model.

Development of Partial Discharging Simulation Test Equipment

Science.gov (United States)

Kai, Xue; Genghua, Liu; Yan, Jia; Ziqi, Chai; Jian, Lu

2017-12-01

In the case of partial discharge training for recruits who lack of on-site work experience, the risk of physical shock and damage of the test equipment may be due to the limited skill level and improper operation by new recruits. Partial discharge simulation tester is the use of simulation technology to achieve partial discharge test process simulation, relatively true reproduction of the local discharge process and results, so that the operator in the classroom will be able to get familiar with and understand the use of the test process and equipment.The teacher sets up the instrument to display different partial discharge waveforms so that the trainees can analyze the test results of different partial discharge types.

Dirt bikes and all terrain vehicles: the real threat to pediatric kidneys.

Science.gov (United States)

Wu, Hsi-Yang; Gaines, Barbara A

2007-10-01

Recent reviews show that bicycles are the major cause of significant renal injury with few injuries occurring during contact sports. All-terrain vehicles are also responsible for significant pediatric renal trauma. We determined whether dirt bikes and all-terrain vehicles cause more significant renal injuries than contact sports. A retrospective review of our pediatric trauma database revealed 115 consecutive patients treated for renal trauma from 2000 to 2005. A total of 20 bicycle injuries occurred, including 6 on dirt bikes. A total of 13 all-terrain vehicle injuries occurred, including 4 involving rollovers. A total of 12 contact sport injuries occurred, including 2 during pick-up games. The mean grade of renal injury was compared among the mechanisms, with grades III-V considered high grade. In descending order of renal injury the mechanisms were dirt bike (2.8), all-terrain vehicle rollover (2.8), bicycle (2.3), all-terrain vehicle (2.1), contact sports (1.8) and organized contact sports (1.4). Dirt bikes and all-terrain vehicle rollovers caused significantly greater renal trauma than organized contact sports (2.8 vs 1.4, p = 0.007 and 0.02, respectively), whereas overall bicycle and all-terrain vehicle accidents resulted in similar renal trauma grades compared to those of all contact sports. The 2 high grade renal injuries during contact sports occurred during pick-up football games without protective gear. Physician advice regarding children with a solitary kidney should include avoiding dirt bikes and all-terrain vehicles. Efforts to limit all-terrain vehicle use in children younger than 16 years would decrease the risk of significant renal injury in this population more effectively than limiting contact sports participation.

Helicopter Field Testing of NASA's Autonomous Landing and Hazard Avoidance Technology (ALHAT) System fully Integrated with the Morpheus Vertical Test Bed Avionics

Science.gov (United States)

Epp, Chirold D.; Robertson, Edward A.; Ruthishauser, David K.

2013-01-01

The Autonomous Landing and Hazard Avoidance Technology (ALHAT) Project was chartered to develop and mature to a Technology Readiness Level (TRL) of six an autonomous system combining guidance, navigation and control with real-time terrain sensing and recognition functions for crewed, cargo, and robotic planetary landing vehicles. The ALHAT System must be capable of identifying and avoiding surface hazards to enable a safe and accurate landing to within tens of meters of designated and certified landing sites anywhere on a planetary surface under any lighting conditions. This is accomplished with the core sensing functions of the ALHAT system: Terrain Relative Navigation (TRN), Hazard Detection and Avoidance (HDA), and Hazard Relative Navigation (HRN). The NASA plan for the ALHAT technology is to perform the TRL6 closed loop demonstration on the Morpheus Vertical Test Bed (VTB). The first Morpheus vehicle was lost in August of 2012 during free-flight testing at Kennedy Space Center (KSC), so the decision was made to perform a helicopter test of the integrated ALHAT System with the Morpheus avionics over the ALHAT planetary hazard field at KSC. The KSC helicopter tests included flight profiles approximating planetary approaches, with the entire ALHAT system interfaced with all appropriate Morpheus subsystems and operated in real-time. During these helicopter flights, the ALHAT system imaged the simulated lunar terrain constructed in FY2012 to support ALHAT/Morpheus testing at KSC. To the best of our knowledge, this represents the highest fidelity testing of a system of this kind to date. During this helicopter testing, two new Morpheus landers were under construction at the Johnson Space Center to support the objective of an integrated ALHAT/Morpheus free-flight demonstration. This paper provides an overview of this helicopter flight test activity, including results and lessons learned, and also provides an overview of recent integrated testing of ALHAT on the second

Continuous free-crab gaits for hexapod robots on a natural terrain with forbidden zones: An application to humanitarian demining

OpenAIRE

Estremera, Joaquín; Cobano, José A.; González de Santos, Pablo

2010-01-01

Autonomous robots are leaving the laboratories to master new outdoor applications, and walking robots in particular have already shown their potential advantages in these environments, especially on a natural terrain. Gait generation is the key to success in the negotiation of natural terrain with legged robots; however, most of the algorithms devised for hexapods have been tested under laboratory conditions. This paper presents the development of crab and turning gaits for hexapod robots on ...

Large-eddy simulation of atmospheric flow over complex terrain

DEFF Research Database (Denmark)

Bechmann, Andreas

2007-01-01

The present report describes the development and validation of a turbulence model designed for atmospheric flows based on the concept of Large-Eddy Simulation (LES). The background for the work is the high Reynolds number k - #epsilon# model, which has been implemented on a finite-volume code...... turbulence model is able to handle both engineering and atmospheric flows and can be run in both RANS or LES mode. For LES simulations a time-dependent wind field that accurately represents the turbulent structures of a wind environment must be prescribed at the computational inlet. A method is implemented...... where the turbulent wind field from a separate LES simulation can be used as inflow. To avoid numerical dissipation of turbulence special care is paid to the numerical method, e.g. the turbulence model is calibrated with the specific numerical scheme used. This is done by simulating decaying isotropic...

An Optimized Method for Terrain Reconstruction Based on Descent Images

Directory of Open Access Journals (Sweden)

Xu Xinchao

2016-02-01

Full Text Available An optimization method is proposed to perform high-accuracy terrain reconstruction of the landing area of Chang’e III. First, feature matching is conducted using geometric model constraints. Then, the initial terrain is obtained and the initial normal vector of each point is solved on the basis of the initial terrain. By changing the vector around the initial normal vector in small steps a set of new vectors is obtained. By combining these vectors with the direction of light and camera, the functions are set up on the basis of a surface reflection model. Then, a series of gray values is derived by solving the equations. The new optimized vector is recorded when the obtained gray value is closest to the corresponding pixel. Finally, the optimized terrain is obtained after iteration of the vector field. Experiments were conducted using the laboratory images and descent images of Chang’e III. The results showed that the performance of the proposed method was better than that of the classical feature matching method. It can provide a reference for terrain reconstruction of the landing area in subsequent moon exploration missions.

Terrain Simplification Research in Augmented Scene Modeling

Institute of Scientific and Technical Information of China (English)

无

2001-01-01

environment. As one of the most important tasks in augmented scene modeling, terrain simplification research has gained more and more attention. In this paper, we mainly focus on point selection problem in terrain simplification using triangulated irregular network. Based on the analysis and comparison of traditional importance measures for each input point, we put forward a new importance measure based on local entropy. The results demonstrate that the local entropy criterion has a better performance than any traditional methods. In addition, it can effectively conquer the "short-sight" problem associated with the traditional methods.

RailSiTe® (Rail Simulation and Testing

Directory of Open Access Journals (Sweden)

Martin Johne

2016-10-01

Full Text Available RailSiTe® (Rail Simulation and Testing is DLR’s rail simulation and testing laboratory (see Figure 1. It is the implementation of a fully modular concept for the simulation of on-board and trackside control and safety technology. The RailSiTe® laboratory additionally comprises the RailSET (Railway Simulation Environment for Train Drivers and Operators human-factors laboratory, a realistic environment containing a realistic train mockup including 3D simulation.

Pre-analysis techniques applied to area-based correlation aiming Digital Terrain Model generation

Directory of Open Access Journals (Sweden)

Maurício Galo

2005-12-01

Full Text Available Area-based matching is an useful procedure in some photogrammetric processes and its results are of crucial importance in applications such as relative orientation, phototriangulation and Digital Terrain Model generation. The successful determination of correspondence depends on radiometric and geometric factors. Considering these aspects, the use of procedures that previously estimate the quality of the parameters to be computed is a relevant issue. This paper describes these procedures and it is shown that the quality prediction can be computed before performing matching by correlation, trough the analysis of the reference window. This procedure can be incorporated in the correspondence process for Digital Terrain Model generation and Phototriangulation. The proposed approach comprises the estimation of the variance matrix of the translations from the gray levels in the reference window and the reduction of the search space using the knowledge of the epipolar geometry. As a consequence, the correlation process becomes more reliable, avoiding the application of matching procedures in doubtful areas. Some experiments with simulated and real data are presented, evidencing the efficiency of the studied strategy.

Lunar terrain mapping and relative-roughness analysis

Science.gov (United States)

Rowan, Lawrence C.; McCauley, John F.; Holm, Esther A.

1971-01-01

Terrain maps of the equatorial zone (long 70° E.-70° W. and lat 10° N-10° S.) were prepared at scales of 1:2,000,000 and 1:1,000,000 to classify lunar terrain with respect to roughness and to provide a basis for selecting sites for Surveyor and Apollo landings as well as for Ranger and Lunar Orbiter photographs. The techniques that were developed as a result of this effort can be applied to future planetary exploration. By using the best available earth-based observational data and photographs 1:1,000,000-scale and U.S. Geological Survey lunar geologic maps and U.S. Air Force Aeronautical Chart and Information Center LAC charts, lunar terrain was described by qualitative and quantitative methods and divided into four fundamental classes: maria, terrae, craters, and linear features. Some 35 subdivisions were defined and mapped throughout the equatorial zone, and, in addition, most of the map units were illustrated by photographs. The terrain types were analyzed quantitatively to characterize and order their relative-roughness characteristics. Approximately 150,000 east-west slope measurements made by a photometric technique (photoclinometry) in 51 sample areas indicate that algebraic slope-frequency distributions are Gaussian, and so arithmetic means and standard deviations accurately describe the distribution functions. The algebraic slope-component frequency distributions are particularly useful for rapidly determining relative roughness of terrain. The statistical parameters that best describe relative roughness are the absolute arithmetic mean, the algebraic standard deviation, and the percentage of slope reversal. Statistically derived relative-relief parameters are desirable supplementary measures of relative roughness in the terrae. Extrapolation of relative roughness for the maria was demonstrated using Ranger VII slope-component data and regional maria slope data, as well as the data reported here. It appears that, for some morphologically homogeneous

Simulation and Verificaiton of Flow in Test Methods

DEFF Research Database (Denmark)

Thrane, Lars Nyholm; Szabo, Peter; Geiker, Mette Rica

2005-01-01

Simulations and experimental results of L-box and slump flow test of a self-compacting mortar and a self-compacting concrete are compared. The simulations are based on a single fluid approach and assume an ideal Bingham behavior. It is possible to simulate the experimental results of both tests...

What Influences Youth to Operate All-Terrain Vehicles Safely?

Science.gov (United States)

Grummon, A. H.; Heaney, C. A.; Dellinger, W. A.; Wilkins, J. R., III

2014-01-01

The operation of all-terrain vehicles (ATVs) by youth has contributed to the incidence of serious and fatal injuries among children. This study explored factors related to the frequency with which youth wore a helmet and refrained from engaging in three risky driving behaviors (driving at risky speeds, on paved roads and on unfamiliar terrain)…

Wind Turbine Loads Induced by Terrain and Wakes: An Experimental Study through Vibration Analysis and Computational Fluid Dynamics

Directory of Open Access Journals (Sweden)

Francesco Castellani

2017-11-01

Full Text Available A wind turbine is a very well-known archetype of energy conversion system working at non-stationary regimes. Despite this, a deep mechanical comprehension of wind turbines operating in complicated conditions is still challenging, especially as regards the analysis of experimental data. In particular, wind turbines in complex terrain represent a very valuable testing ground because of the possible combination of wake effects among nearby turbines and flow accelerations caused by the terrain morphology. For these reasons, in this work, a cluster of four full-scale wind turbines from a very complex site is studied. The object of investigation is vibrations, at the level of the structure (tower and drive-train. Data collected by the on-board condition monitoring system are analyzed and interpreted in light of the knowledge of wind conditions and operating parameters collected by the Supervisory Control And Data Acquisition (SCADA. A free flow Computational Fluid Dynamics (CFD simulation is also performed, and it allows one to better interpret the vibration analysis. The main outcome is the interpretation of how wakes and flow turbulences appear in the vibration signals, both at the structural level and at the drive-train level. Therefore, this wind to gear approach builds a connection between flow phenomena and mechanical phenomena in the form of vibrations, representing a precious tool for assessing loads in different working conditions.

Standard Specification for Solar Simulation for Terrestrial Photovoltaic Testing

CERN Document Server

American Society for Testing and Materials. Philadelphia

2010-01-01

1.1 This specification provides means for classifying solar simulators intended for indoor testing of photovoltaic devices (solar cells or modules), according to their spectral match to a reference spectral irradiance, non-uniformity of spatial irradiance, and temporal instability of irradiance. 1.2 Testing of photovoltaic devices may require the use of solar simulators. Test Methods that require specific classification of simulators as defined in this specification include Test Methods E948, E1036, and E1362. 1.3 This standard is applicable to both pulsed and steady state simulators and includes recommended test requirements used for classifying such simulators. 1.4 A solar simulator usually consists of three major components: (1) light source(s) and associated power supply; (2) any optics and filters required to modify the output beam to meet the classification requirements in Section 4; and (3) the necessary controls to operate the simulator, adjust irradiance, etc. 1.5 A light source that does not mee...

Finite element simulations of two rock mechanics tests

International Nuclear Information System (INIS)

Dahlke, H.J.; Lott, S.A.

1986-04-01

Rock mechanics tests are performed to determine in situ stress conditions and material properties of an underground rock mass. To design stable underground facilities for the permanent storage of high-level nuclear waste, determination of these properties and conditions is a necessary first step. However, before a test and its associated equipment can be designed, the engineer needs to know the range of expected values to be measured by the instruments. Sensitivity studies by means of finite element simulations are employed in this preliminary design phase to evaluate the pertinent parameters and their effects on the proposed measurements. The simulations, of two typical rock mechanics tests, the plate bearing test and the flat-jack test, by means of the finite element analysis, are described. The plate bearing test is used to determine the rock mass deformation modulus. The flat-jack test is used to determine the in situ stress conditions of the host rock. For the plate bearing test, two finite element models are used to simulate the classic problem of a load on an elastic half space and the actual problem of a plate bearing test in an underground tunnel of circular cross section. For the flat-jack simulation, a single finite element model is used to simulate both horizontal and vertical slots. Results will be compared to closed-form solutions available in the literature

Simulating lightning tests to radar system

NARCIS (Netherlands)

Blaj, M.A.; Buesink, Frederik Johannes Karel; Leferink, Frank Bernardus Johannes

2010-01-01

The risk of destruction due to lightning makes simulating the effects of lightning strikes a necessity. We modeled a radar enclosure and simulated the effect of a lightning strike. The results have been validated using full threat lightning current tests.

Conceptual design for simulator of irradiation test reactors

International Nuclear Information System (INIS)

Takemoto, Noriyuki; Ohto, Tsutomu; Magome, Hirokatsu; Izumo, Hironobu; Hori, Naohiko

2012-03-01

A simulator of irradiation test reactors has been developed since JFY 2010 for understanding reactor behavior and for upskilling in order to utilize a nuclear human resource development (HRD) and to promote partnership with developing countries which have a plan to introduce nuclear power plant. The simulator is designed based on the JMTR, one of the irradiation test reactors, and it simulates operation, irradiation tests and various kinds of accidents caused by the reactor and irradiation facility. The development of the simulator is sponsored by the Japanese government as one of the specialized projects of advanced research infrastructure in order to promote basic as well as applied researches. The training using the simulator will be started for the nuclear HRD from JFY 2012. This report summarizes the result of the conceptual design of the simulator in JFY 2010. (author)

Using game engine for 3D terrain visualisation of GIS data: A review

Science.gov (United States)

Che Mat, Ruzinoor; Shariff, Abdul Rashid Mohammed; Nasir Zulkifli, Abdul; Shafry Mohd Rahim, Mohd; Hafiz Mahayudin, Mohd

2014-06-01

This paper reviews on the 3D terrain visualisation of GIS data using game engines that are available in the market as well as open source. 3D terrain visualisation is a technique used to visualise terrain information from GIS data such as a digital elevation model (DEM), triangular irregular network (TIN) and contour. Much research has been conducted to transform the 2D view of map to 3D. There are several terrain visualisation softwares that are available for free, which include Cesium, Hftool and Landserf. This review paper will help interested users to better understand the current state of art in 3D terrain visualisation of GIS data using game engines.

Using game engine for 3D terrain visualisation of GIS data: A review

International Nuclear Information System (INIS)

Mat, Ruzinoor Che; Zulkifli, Abdul Nasir; Mahayudin, Mohd Hafiz; Shariff, Abdul Rashid Mohammed; Rahim, Mohd Shafry Mohd

2014-01-01

This paper reviews on the 3D terrain visualisation of GIS data using game engines that are available in the market as well as open source. 3D terrain visualisation is a technique used to visualise terrain information from GIS data such as a digital elevation model (DEM), triangular irregular network (TIN) and contour. Much research has been conducted to transform the 2D view of map to 3D. There are several terrain visualisation softwares that are available for free, which include Cesium, Hftool and Landserf. This review paper will help interested users to better understand the current state of art in 3D terrain visualisation of GIS data using game engines

An open source high-performance solution to extract surface water drainage networks from diverse terrain conditions

Science.gov (United States)

Stanislawski, Larry V.; Survila, Kornelijus; Wendel, Jeffrey; Liu, Yan; Buttenfield, Barbara P.

2018-01-01

This paper describes a workflow for automating the extraction of elevation-derived stream lines using open source tools with parallel computing support and testing the effectiveness of procedures in various terrain conditions within the conterminous United States. Drainage networks are extracted from the US Geological Survey 1/3 arc-second 3D Elevation Program elevation data having a nominal cell size of 10 m. This research demonstrates the utility of open source tools with parallel computing support for extracting connected drainage network patterns and handling depressions in 30 subbasins distributed across humid, dry, and transitional climate regions and in terrain conditions exhibiting a range of slopes. Special attention is given to low-slope terrain, where network connectivity is preserved by generating synthetic stream channels through lake and waterbody polygons. Conflation analysis compares the extracted streams with a 1:24,000-scale National Hydrography Dataset flowline network and shows that similarities are greatest for second- and higher-order tributaries.

Effect on tracer concentrations of ABL depth models in complex terrain

Energy Technology Data Exchange (ETDEWEB)

Galmarini, S.; Salin, P. [Joint Research Center Ispra (Italy); Anfossi, D.; Trini-Castelli, S. [CNR-ICGF, Turin (Italy); Schayes, G. [Univ. Louvain-la-Neuve, Louvain (Belgium)

1997-10-01

In the present preliminary study we use different ABL (atmospheric boundary layer) depth formulations to study atmospheric dispersion in complex-terrain conditions. The flow in an Alpine valley during the tracer experiment TRANSALP is simulated by means of a mesoscale model and a tracer dispersion is reproduced using a Lagrangian particle model. The ABL dept enters as key parameter in particle model turbulent-dispersion formulation. The preliminary results reveal that the ABL depth parameter can influence the dispersion process but that in the case of a dispersion in a valley-daytime flow the results depend much more strongly on the model horizontal and vertical resolution. A relatively coarse horizontal resolution implies a considerable smoothing of the topography that largely affects the dispersion characteristics. The vertical resolution does not allow on to resolve with sufficient details the rapid and large variation of the flow characteristic as the terrain feature vary. Two of the methods used to determine the ABL depth depend strongly on the resolution. The method that instead depends only on surface parameters like heat flux and surface based stability allowed us to obtain results to be considered satisfactory for what concerns the dispersion process, quite consistent with the flow model results, less numeric dependent and more physically sound. (LN)

High Severity Wildfire Effect On Rainfall Infiltration And Runoff: A Cellular Automata Based Simulation

Science.gov (United States)

Vergara-Blanco, J. E.; Leboeuf-Pasquier, J.; Benavides-Solorio, J. D. D.

2017-12-01

A simulation software that reproduces rainfall infiltration and runoff for a storm event in a particular forest area is presented. A cellular automaton is utilized to represent space and time. On the time scale, the simulation is composed by a sequence of discrete time steps. On the space scale, the simulation is composed of forest surface cells. The software takes into consideration rain intensity and length, individual forest cell soil absorption capacity evolution, and surface angle of inclination. The software is developed with the C++ programming language. The simulation is executed on a 100 ha area within La Primavera Forest in Jalisco, Mexico. Real soil texture for unburned terrain and high severity wildfire affected terrain is employed to recreate the specific infiltration profile. Historical rainfall data of a 92 minute event is used. The Horton infiltration equation is utilized for infiltration capacity calculation. A Digital Elevation Model (DEM) is employed to reproduce the surface topography. The DEM is displayed with a 3D mesh graph where individual surface cells can be observed. The plot colouring renders water content development at the cell level throughout the storm event. The simulation shows that the cumulative infiltration and runoff which take place at the surface cell level depend on the specific storm intensity, fluctuation and length, overall terrain topography, cell slope, and soil texture. Rainfall cumulative infiltration for unburned and high severity wildfire terrain are compared: unburned terrain exhibits a significantly higher amount of rainfall infiltration.It is concluded that a cellular automaton can be utilized with a C++ program to reproduce rainfall infiltration and runoff under diverse soil texture, topographic and rainfall conditions in a forest setting. This simulation is geared for an optimization program to pinpoint the locations of a series of forest land remediation efforts to support reforestation or to minimize runoff.

Conically scanning lidar error in complex terrain

Directory of Open Access Journals (Sweden)

Ferhat Bingöl

2009-05-01

Full Text Available Conically scanning lidars assume the flow to be homogeneous in order to deduce the horizontal wind speed. However, in mountainous or complex terrain this assumption is not valid implying a risk that the lidar will derive an erroneous wind speed. The magnitude of this error is measured by collocating a meteorological mast and a lidar at two Greek sites, one hilly and one mountainous. The maximum error for the sites investigated is of the order of 10 %. In order to predict the error for various wind directions the flows at both sites are simulated with the linearized flow model, WAsP Engineering 2.0. The measurement data are compared with the model predictions with good results for the hilly site, but with less success at the mountainous site. This is a deficiency of the flow model, but the methods presented in this paper can be used with any flow model.

A high resolution complex terrain dispersion study in the Rocky Flats, Colorado vicinity

International Nuclear Information System (INIS)

Poulos, G.S.; Bossert, J.E.

1992-01-01

In January/February, 1991 an intensive set of measurements was taken around Rocky Flats near Denver, CO under the auspices of the Department of Energy Atmospheric Studies over Complex Terrain (ASCOT) program. This region of the country is known as the Front Range, and is characterized by a transition from the relatively flat terrain of the Great Plains to the highly varied terrain of the Rocky Mountains. One goal of the ASCOT 1991 program was to gain insight into multi-scale meteorological interaction by observing wintertime drainage conditions at the mountain-valley-plains interface. ASCOT data included surface and upper air measurements on approximately a 50km 2 scale. Simultaneously, an SF 6 tracer release study was being conducted around Rocky Flats, a nuclear materials production facility. Detailed surface concentration measurements were completed for the SF 6 plume. This combination of meteorological and tracer concentration data provided a unique data set for comparisons of mesoscale and dispersion modeling results with observations and for evaluating our capability to predict pollutant transport. Our approach is to use the Regional Atmospheric Modeling System (RAMS) mesoscale model to simulate atmospheric conditions and the Lagrangian Particle Dispersion Model (LPDM), a component of the RAMS system, to model the dispersion of the SF 6 . We have chosen the 4--5 February, 1991 overnight period as our case study. This night was characterized by strong drainage flows from the Rocky Mountains to the west of Rocky Flats, southerly winds in a layer about lkm thick above the drainage flows, and northwesterly winds above that layer extending to the tropopause

Automating the simulator testing and data collection process

Energy Technology Data Exchange (ETDEWEB)

Magi, T.; Dimitri-Hakim, R. [L-3 Communications MAPPS Inc., Montreal, Quebec (Canada)

2012-07-01

Scenario-based training is a key process in the use of Full Scope Simulators (FSS) for operator training. Scenario-based training can be defined as any set of simulated plant operations performed with a specific training objective in mind. In order to meet this training objective, the ANSI/ANS-3.5-2009 standard requires that certain simulator training scenarios be tested to ensure that they reproduce the expected plant responses, that all plant procedures can be followed, and that scenario-based training objectives can be met. While malfunction testing provided a narrow view of the simulator performance revolving around the malfunction itself, scenario testing provides a broader, overall view. The concept of instructor validation of simulator scenarios to be used for training and evaluation, and oversight of simulator performance during the validation process, work hand-in-hand. This is where Scenario-Based Testing comes into play. With the description of Scenario-Based Testing (SBT) within Nuclear Energy Institute NEI 09-09 white paper and within the ANSI/ANS-3.5-2009 standard, the industry now has a way forward that reduces the regulatory uncertainty. Together, scenario-based testing and scenario-based training combine to produce better simulators which in turn can be used to more effectively and efficiently train new and existing power plant operators. However, they also impose a significant data gathering and analysis burden on FSS users. L-3 MAPPS Orchid Instructor Station (Orchid IS) facilitates this data gathering and analysis by providing features that automate this process with a simple, centralized, easy to use interface. (author)

Bathymetric terrain model of the Atlantic margin for marine geological investigations

Science.gov (United States)

Andrews, Brian D.; Chaytor, Jason D.; ten Brink, Uri S.; Brothers, Daniel S.; Gardner, James V.; Lobecker, Elizabeth A.; Calder, Brian R.

2016-01-01

A bathymetric terrain model of the Atlantic margin covering almost 725,000 square kilometers of seafloor from the New England Seamounts in the north to the Blake Basin in the south is compiled from existing multibeam bathymetric data for marine geological investigations. Although other terrain models of the same area are extant, they are produced from either satellite-derived bathymetry at coarse resolution (ETOPO1), or use older bathymetric data collected by using a combination of single beam and multibeam sonars (Coastal Relief Model). The new multibeam data used to produce this terrain model have been edited by using hydrographic data processing software to maximize the quality, usability, and cartographic presentation of the combined 100-meter resolution grid. The final grid provides the largest high-resolution, seamless terrain model of the Atlantic margin..

Cyber-Physical Energy Systems Modeling, Test Specification, and Co-Simulation Based Testing

DEFF Research Database (Denmark)

van der Meer, A. A.; Palensky, P.; Heussen, Kai

2017-01-01

The gradual deployment of intelligent and coordinated devices in the electrical power system needs careful investigation of the interactions between the various domains involved. Especially due to the coupling between ICT and power systems a holistic approach for testing and validating is required....... Taking existing (quasi-) standardised smart grid system and test specification methods as a starting point, we are developing a holistic testing and validation approach that allows a very flexible way of assessing the system level aspects by various types of experiments (including virtual, real......, and mixed lab settings). This paper describes the formal holistic test case specification method and applies it to a particular co-simulation experimental setup. The various building blocks of such a simulation (i.e., FMI, mosaik, domain-specific simulation federates) are covered in more detail...

Predicting forest height using the GOST, Landsat 7 ETM+, and airborne LiDAR for sloping terrains in the Greater Khingan Mountains of China

NARCIS (Netherlands)

Gu, Chengyan; Clevers, Jan G.P.W.; Liu, Xiao; Tian, Xin; Li, Zhouyuan; Li, Zengyuan

2018-01-01

Sloping terrain of forests is an overlooked factor in many models simulating the canopy bidirectional reflectance distribution function, which limits the estimation accuracy of forest vertical structure parameters (e.g., forest height). The primary objective of this study was to predict forest

TERRAIN Submission for Waushara Countywide DFIRM

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain for Middlesex County, NJ

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that were used to create...

DCS Terrain Submission for Seminole, GA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain Submission for Stephens, OK

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, Pointe Coupee PARISH, LA, USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain Submission for Carter, OK

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain Submission for Mono, CA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

Terrain Sumbission for Howard County NE

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN Submission for Outagamie Countywide DFIRM

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, ESSEX COUNTY, MASSACHUSETTS - Coastal PMR

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain for HOUSTON COUNTY, ALABAMA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain for Clay County, GA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, UPPER CUMBERLAND WATERSHED, KENTUCKY USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

Terrain, CEDAR RAPIDS, LINN COUNTY, IA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain Submission for Irwin, GA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain Submission for Brazos TX

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain for Harris County, GA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN Submission for CHISAGO COUNTY, MN

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describe the digital topographic data that were used to create...

DCS Terrain for Jasper County, GA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain Submission for Garvin, OK

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

Terrain Data, Queen Anne's COUNTY, USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain for Gilmer County, GA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain Submission for Houston TX

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain for Marion County, GA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain for Washington County, GA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain Submission for Sioux Falls

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain Submission for Mohave, AZ

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain for Hancock County, GA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, ST. CLAIR COUNTY, ALABAMA USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain for Lincoln County, GA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain for Greene County, GA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, CERRO GORDO COUNTY, IOWA, USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain Submission for Merced, CA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain Submission for Ouachita, AR

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain for Pickens County, GA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain for Williamson County, TX

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain Submission for Clark, AR

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain Submission for Drew AR

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain for Cobb County, GA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, ST. LOUIS COUNTY, Missouri USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain Submission for Logan, OK

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

Influences of Appalachian orography on heavy rainfall and rainfall variability associated with the passage of hurricane Isabel by ensemble simulations

Science.gov (United States)

Oldaker, Guy; Liu, Liping; Lin, Yuh-Lang

2017-12-01

This study focuses on the heavy rainfall event associated with hurricane Isabel's (2003) passage over the Appalachian mountains of the eastern United States. Specifically, an ensemble consisting of two groups of simulations using the Weather Research and Forecasting model (WRF), with and without topography, is performed to investigate the orographic influences on heavy rainfall and rainfall variability. In general, the simulated ensemble mean with full terrain is able to reproduce the key observed 24-h rainfall amount and distribution, while the flat-terrain mean lacks in this respect. In fact, 30-h rainfall amounts are reduced by 75% with the removal of topography. Rainfall variability is also significantly increased with the presence of orography. Further analysis shows that the complex interaction between the hurricane and terrain along with contributions from varied microphysics, cumulus parametrization, and planetary boundary layer schemes have a pronounced effect on rainfall and rainfall variability. This study follows closely with a previous study, but for a different TC case of Isabel (2003). It is an important sensitivity test for a different TC in a very different environment. This study reveals that the rainfall variability behaves similarly, even with different settings of the environment.

GIS-based terrain analysis of linear infrastructure corridors in the Mackenzie River Valley, NWT

International Nuclear Information System (INIS)

Ednie, M.; Wright, J.F.; Duchesne, C.

2007-01-01

The impact of global warming on permafrost terrain was discussed with particular reference to the structural stability and performance reliability of the proposed pipelines and roads in the Mackenzie River Valley in the Northwest Territories. Engineers, regulators and decision makers responsible for the development of these networks must have access to information about current and future terrain conditions, both local and regional. The Geological Survey of Canada is developing an ArcGIS resident, multi-component terrain analysis methodology for evaluating permafrost terrain in terms of the probable geothermal and geomorphological responses to climate warming. A GIS-integrated finite-element transient ground thermal model (T-ONE) can predict local-regional permafrost conditions and future responses of permafrost to climate warming. The influences of surface and channel hydrology on local erosion potentials can be determined by analyzing the topographic and topologic characteristics of the terrain. A weights of evidence-based landscape-process model, currently under development, will consider multiple terrain factors for mapping terrain that is susceptible to slope failure, subsidence or erosion. This terrain analysis methodology is currently being applied to a 2 km buffer spanning the proposed Mackenzie Gas Pipeline right-of-way, and along winter and all-weather road networks in the Mackenzie River Valley. Initial ground thermal modeling has identified thermally sensitive terrain for which permafrost will either completely disappear or warm significantly to near isothermal conditions within the next 25 to 55 years

Preparation and Integration of ALHAT Precision Landing Technology for Morpheus Flight Testing

Science.gov (United States)

Carson, John M., III; Robertson, Edward A.; Pierrottet, Diego F.; Roback, Vincent E.; Trawny, Nikolas; Devolites, Jennifer L.; Hart, Jeremy J.; Estes, Jay N.; Gaddis, Gregory S.

2014-01-01

The Autonomous precision Landing and Hazard Avoidance Technology (ALHAT) project has developed a suite of prototype sensors for enabling autonomous and safe precision land- ing of robotic or crewed vehicles on solid solar bodies under varying terrain lighting condi- tions. The sensors include a Lidar-based Hazard Detection System (HDS), a multipurpose Navigation Doppler Lidar (NDL), and a long-range Laser Altimeter (LAlt). Preparation for terrestrial ight testing of ALHAT onboard the Morpheus free- ying, rocket-propelled ight test vehicle has been in progress since 2012, with ight tests over a lunar-like ter- rain eld occurring in Spring 2014. Signi cant work e orts within both the ALHAT and Morpheus projects has been required in the preparation of the sensors, vehicle, and test facilities for interfacing, integrating and verifying overall system performance to ensure readiness for ight testing. The ALHAT sensors have undergone numerous stand-alone sensor tests, simulations, and calibrations, along with integrated-system tests in special- ized gantries, trucks, helicopters and xed-wing aircraft. A lunar-like terrain environment was constructed for ALHAT system testing during Morpheus ights, and vibration and thermal testing of the ALHAT sensors was performed based on Morpheus ights prior to ALHAT integration. High- delity simulations were implemented to gain insight into integrated ALHAT sensors and Morpheus GN&C system performance, and command and telemetry interfacing and functional testing was conducted once the ALHAT sensors and electronics were integrated onto Morpheus. This paper captures some of the details and lessons learned in the planning, preparation and integration of the individual ALHAT sen- sors, the vehicle, and the test environment that led up to the joint ight tests.

Terrain Extraction by Integrating Terrestrial Laser Scanner Data and Spectral Information

Science.gov (United States)

Lau, C. L.; Halim, S.; Zulkepli, M.; Azwan, A. M.; Tang, W. L.; Chong, A. K.

2015-10-01

The extraction of true terrain points from unstructured laser point cloud data is an important process in order to produce an accurate digital terrain model (DTM). However, most of these spatial filtering methods just utilizing the geometrical data to discriminate the terrain points from nonterrain points. The point cloud filtering method also can be improved by using the spectral information available with some scanners. Therefore, the objective of this study is to investigate the effectiveness of using the three-channel (red, green and blue) of the colour image captured from built-in digital camera which is available in some Terrestrial Laser Scanner (TLS) for terrain extraction. In this study, the data acquisition was conducted at a mini replica landscape in Universiti Teknologi Malaysia (UTM), Skudai campus using Leica ScanStation C10. The spectral information of the coloured point clouds from selected sample classes are extracted for spectral analysis. The coloured point clouds which within the corresponding preset spectral threshold are identified as that specific feature point from the dataset. This process of terrain extraction is done through using developed Matlab coding. Result demonstrates that a higher spectral resolution passive image is required in order to improve the output. This is because low quality of the colour images captured by the sensor contributes to the low separability in spectral reflectance. In conclusion, this study shows that, spectral information is capable to be used as a parameter for terrain extraction.

Autonomous terrain characterization and modelling for dynamic control of unmanned vehicles

Science.gov (United States)

Talukder, A.; Manduchi, R.; Castano, R.; Owens, K.; Matthies, L.; Castano, A.; Hogg, R.

2002-01-01

This end-to-end obstacle negotiation system is envisioned to be useful in optimized path planning and vehicle navigation in terrain conditions cluttered with vegetation, bushes, rocks, etc. Results on natural terrain with various natural materials are presented.

An Effective Terrain Aided Navigation for Low-Cost Autonomous Underwater Vehicles.

Science.gov (United States)

Zhou, Ling; Cheng, Xianghong; Zhu, Yixian; Dai, Chenxi; Fu, Jinbo

2017-03-25

Terrain-aided navigation is a potentially powerful solution for obtaining submerged position fixes for autonomous underwater vehicles. The application of terrain-aided navigation with high-accuracy inertial navigation systems has demonstrated meter-level navigation accuracy in sea trials. However, available sensors may be limited depending on the type of the mission. Such limitations, especially for low-grade navigation sensors, not only degrade the accuracy of traditional navigation systems, but further impact the ability to successfully employ terrain-aided navigation. To address this problem, a tightly-coupled navigation is presented to successfully estimate the critical sensor errors by incorporating raw sensor data directly into an augmented navigation system. Furthermore, three-dimensional distance errors are calculated, providing measurement updates through the particle filter for absolute and bounded position error. The development of the terrain aided navigation system is elaborated for a vehicle equipped with a non-inertial-grade strapdown inertial navigation system, a 4-beam Doppler Velocity Log range sensor and a sonar altimeter. Using experimental data for navigation performance evaluation in areas with different terrain characteristics, the experiment results further show that the proposed method can be successfully applied to the low-cost AUVs and significantly improves navigation performance.

Test requirements for the integral effect test to simulate Korean PWR plants

Energy Technology Data Exchange (ETDEWEB)

Song, Chul Hwa; Park, C. K.; Lee, S. J.; Kwon, T. S.; Yun, B. J.; Chung, M. K

2001-02-01

In this report, the test requirements are described for the design of the integral effect test facility to simulate Korean PWR plants. Since the integral effect test facility should be designed so as to simulate various thermal hydraulic phenomena, as closely as possible, to be occurred in real plants during operation or anticipated transients, the design and operational characteristics of the reference plants (Korean Standard Nuclear Plant and Korean Next Generation Reactor)were analyzed in order to draw major components, systems, and functions to be satisfied or simulated in the test facility. The test matrix is set up by considering major safety concerns of interest and the test objectives to confirm and enhance the safety of the plants. And the analysis and prioritization of the test matrix leads to the general design requirements of the test facility. Based on the general design requirements, the design criteria is set up for the basic and detailed design of the test facility. And finally it is drawn the design requirements specific to the fluid system and measurement system of the test facility. The test requirements in this report will be used as a guideline to the scaling analysis and basic design of the test facility. The test matrix specified in this report can be modified in the stage of main testing by considering the needs of experiments and circumstances at that time.

Test requirements for the integral effect test to simulate Korean PWR plants

International Nuclear Information System (INIS)

Song, Chul Hwa; Park, C. K.; Lee, S. J.; Kwon, T. S.; Yun, B. J.; Chung, M. K.

2001-02-01

In this report, the test requirements are described for the design of the integral effect test facility to simulate Korean PWR plants. Since the integral effect test facility should be designed so as to simulate various thermal hydraulic phenomena, as closely as possible, to be occurred in real plants during operation or anticipated transients, the design and operational characteristics of the reference plants (Korean Standard Nuclear Plant and Korean Next Generation Reactor)were analyzed in order to draw major components, systems, and functions to be satisfied or simulated in the test facility. The test matrix is set up by considering major safety concerns of interest and the test objectives to confirm and enhance the safety of the plants. And the analysis and prioritization of the test matrix leads to the general design requirements of the test facility. Based on the general design requirements, the design criteria is set up for the basic and detailed design of the test facility. And finally it is drawn the design requirements specific to the fluid system and measurement system of the test facility. The test requirements in this report will be used as a guideline to the scaling analysis and basic design of the test facility. The test matrix specified in this report can be modified in the stage of main testing by considering the needs of experiments and circumstances at that time

Flow analysis of HANARO flow simulated test facility

International Nuclear Information System (INIS)

Park, Yong-Chul; Cho, Yeong-Garp; Wu, Jong-Sub; Jun, Byung-Jin

2002-01-01

The HANARO, a multi-purpose research reactor of 30 MWth open-tank-in-pool type, has been under normal operation since its initial critical in February, 1995. Many experiments should be safely performed to activate the utilization of the NANARO. A flow simulated test facility is being developed for the endurance test of reactivity control units for extended life times and the verification of structural integrity of those experimental facilities prior to loading in the HANARO. This test facility is composed of three major parts; a half-core structure assembly, flow circulation system and support system. The half-core structure assembly is composed of plenum, grid plate, core channel with flow tubes, chimney and dummy pool. The flow channels are to be filled with flow orifices to simulate core channels. This test facility must simulate similar flow characteristics to the HANARO. This paper, therefore, describes an analytical analysis to study the flow behavior of the test facility. The computational flow analysis has been performed for the verification of flow structure and similarity of this test facility assuming that flow rates and pressure differences of the core channel are constant. The shapes of flow orifices were determined by the trial and error method based on the design requirements of core channel. The computer analysis program with standard k - ε turbulence model was applied to three-dimensional analysis. The results of flow simulation showed a similar flow characteristic with that of the HANARO and satisfied the design requirements of this test facility. The shape of flow orifices used in this numerical simulation can be adapted for manufacturing requirements. The flow rate and the pressure difference through core channel proved by this simulation can be used as the design requirements of the flow system. The analysis results will be verified with the results of the flow test after construction of the flow system. (author)

Automated testing and reverification for training simulators using SATAR

International Nuclear Information System (INIS)

Charles, R.D.; Gaddy, C.D.; Nargarkar, A.; Colley, R.

1990-01-01

This paper reports that simulators used to train nuclear power plant operators must be recertified periodically to ensure fidelity for training (10 CFR 55.45). The objective of the Simulator Automated Testing and Reverification (SATAR) project was to develop software to reverify dynamic simulator performance automatically. The software resides in a standard configuration personal computer and in the simulator computer; the two computers are linked via serial ports. SATAR will automatically run performance tests, collect and analyze data, and compare data with baseline performance data. With SATAR, support from operations and simulator support personnel can be reduced greatly, and the repeatability of performance tests can be improved

Investigation of Microphysical Parameters within Winter and Summer Type Precipitation Events over Mountainous [Complex] Terrain

International Nuclear Information System (INIS)

Stalker, James R.; Bossert, James E.

1997-10-01

In this study we investigate complex terrain effects on precipitation with RAMS for both in winter and summer cases from a microphysical perspective. We consider a two dimensional east-west topographic cross section in New Mexico representative of the Jemez mountains on the west and the Sangre de Cristo mountains on the east. Located between these two ranges is the Rio Grande Valley. In these two dimensional experiments, variations in DSDs are considered to simulate total precipitation that closely duplicate observed precipitation

The Application of Voltage Transformer Simulator in Electrical Test Training

Science.gov (United States)

Li, Nan; Zhang, Jun; Chai, Ziqi; Wang, Jingpeng; Yang, Baowei

2018-02-01

The voltage transformer test is an important means to monitor its operating state. The accuracy and reliability of the test data is directly related to the test skill level of the operator. However, the risk of test instruments damage, equipment being tested damage and electric shock in operator is caused by improper operation when training the transformer test. In this paper, a simulation device of voltage transformer is set up, and a simulation model is built for the most common 500kV capacitor voltage transformer (CVT), the simulation model can realize several test items of CVT by combing with teaching guidance platform, simulation instrument, complete set of system software and auxiliary equipment in Changchun. Many successful applications show that the simulation device has good practical value and wide application prospect.

Flight-appropriate 3D Terrain-rendering Toolkit for Synthetic Vision, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — The TerraBlocksTM 3D terrain data format and terrain-block-rendering methodology provides an enabling basis for successful commercial deployment of...

Terrain Commander: Unattended Ground-Based Surveillance System

National Research Council Canada - National Science Library

Steadman, Bob

2000-01-01

.... Terrain Commander OASIS provides next generation target detection, classification, and tracking through smart sensor fusion of beamforming acoustic, seismic, passive infrared, and magnetic sensors...

Prototyping and Simulation of Robot Group Intelligence using Kohonen Networks.

Science.gov (United States)

Wang, Zhijun; Mirdamadi, Reza; Wang, Qing

2016-01-01

Intelligent agents such as robots can form ad hoc networks and replace human being in many dangerous scenarios such as a complicated disaster relief site. This project prototypes and builds a computer simulator to simulate robot kinetics, unsupervised learning using Kohonen networks, as well as group intelligence when an ad hoc network is formed. Each robot is modeled using an object with a simple set of attributes and methods that define its internal states and possible actions it may take under certain circumstances. As the result, simple, reliable, and affordable robots can be deployed to form the network. The simulator simulates a group of robots as an unsupervised learning unit and tests the learning results under scenarios with different complexities. The simulation results show that a group of robots could demonstrate highly collaborative behavior on a complex terrain. This study could potentially provide a software simulation platform for testing individual and group capability of robots before the design process and manufacturing of robots. Therefore, results of the project have the potential to reduce the cost and improve the efficiency of robot design and building.

Testability, Test Automation and Test Driven Development for the Trick Simulation Toolkit

Science.gov (United States)

Penn, John

2014-01-01

This paper describes the adoption of a Test Driven Development approach and a Continuous Integration System in the development of the Trick Simulation Toolkit, a generic simulation development environment for creating high fidelity training and engineering simulations at the NASA Johnson Space Center and many other NASA facilities. It describes the approach, and the significant benefits seen, such as fast, thorough and clear test feedback every time code is checked into the code repository. It also describes an approach that encourages development of code that is testable and adaptable.

simulate_CAT: A Computer Program for Post-Hoc Simulation for Computerized Adaptive Testing

Directory of Open Access Journals (Sweden)

İlker Kalender

2015-06-01

Full Text Available This paper presents a computer software developed by the author. The software conducts post-hoc simulations for computerized adaptive testing based on real responses of examinees to paper and pencil tests under different parameters that can be defined by user. In this paper, short information is given about post-hoc simulations. After that, the working principle of the software is provided and a sample simulation with required input files is shown. And last, output files are described

Risk-Aware Planetary Rover Operation: Autonomous Terrain Classification and Path Planning

Science.gov (United States)

Ono, Masahiro; Fuchs, Thoams J.; Steffy, Amanda; Maimone, Mark; Yen, Jeng

2015-01-01

Identifying and avoiding terrain hazards (e.g., soft soil and pointy embedded rocks) are crucial for the safety of planetary rovers. This paper presents a newly developed groundbased Mars rover operation tool that mitigates risks from terrain by automatically identifying hazards on the terrain, evaluating their risks, and suggesting operators safe paths options that avoids potential risks while achieving specified goals. The tool will bring benefits to rover operations by reducing operation cost, by reducing cognitive load of rover operators, by preventing human errors, and most importantly, by significantly reducing the risk of the loss of rovers.

Visuospatial Aptitude Testing Differentially Predicts Simulated Surgical Skill.

Science.gov (United States)

Hinchcliff, Emily; Green, Isabel; Destephano, Christopher; Cox, Mary; Smink, Douglas; Kumar, Amanika; Hokenstad, Erik; Bengtson, Joan; Cohen, Sarah

2018-02-05

To determine if visuospatial perception (VSP) testing is correlated to simulated or intraoperative surgical performance as rated by the American College of Graduate Medical Education (ACGME) milestones. Classification II-2 SETTING: Two academic training institutions PARTICIPANTS: 41 residents, including 19 Brigham and Women's Hospital and 22 Mayo Clinic residents from three different specialties (OBGYN, general surgery, urology). Participants underwent three different tests: visuospatial perception testing (VSP), Fundamentals of Laparoscopic Surgery (FLS®) peg transfer, and DaVinci robotic simulation peg transfer. Surgical grading from the ACGME milestones tool was obtained for each participant. Demographic and subject background information was also collected including specialty, year of training, prior experience with simulated skills, and surgical interest. Standard statistical analysis using Student's t test were performed, and correlations were determined using adjusted linear regression models. In univariate analysis, BWH and Mayo training programs differed in both times and overall scores for both FLS® peg transfer and DaVinci robotic simulation peg transfer (p<0.05 for all). Additionally, type of residency training impacted time and overall score on robotic peg transfer. Familiarity with tasks correlated with higher score and faster task completion (p= 0.05 for all except VSP score). There was no difference in VSP scores by program, specialty, or year of training. In adjusted linear regression modeling, VSP testing was correlated only to robotic peg transfer skills (average time p=0.006, overall score p=0.001). Milestones did not correlate to either VSP or surgical simulation testing. VSP score was correlated with robotic simulation skills but not with FLS skills or ACGME milestones. This suggests that the ability of VSP score to predict competence differs between tasks. Therefore, further investigation is required into aptitude testing, especially prior

CONTEXT-BASED URBAN TERRAIN RECONSTRUCTION FROM UAV-VIDEOS FOR GEOINFORMATION APPLICATIONS

Directory of Open Access Journals (Sweden)

D. Bulatov

2012-09-01

Full Text Available Urban terrain reconstruction has many applications in areas of civil engineering, urban planning, surveillance and defense research. Therefore the needs of covering ad-hoc demand and performing a close-range urban terrain reconstruction with miniaturized and relatively inexpensive sensor platforms are constantly growing. Using (miniaturized unmanned aerial vehicles, (MUAVs, represents one of the most attractive alternatives to conventional large-scale aerial imagery. We cover in this paper a four-step procedure of obtaining georeferenced 3D urban models from video sequences. The four steps of the procedure – orientation, dense reconstruction, urban terrain modeling and geo-referencing – are robust, straight-forward, and nearly fully-automatic. The two last steps – namely, urban terrain modeling from almost-nadir videos and co-registration of models 6ndash; represent the main contribution of this work and will therefore be covered with more detail. The essential substeps of the third step include digital terrain model (DTM extraction, segregation of buildings from vegetation, as well as instantiation of building and tree models. The last step is subdivided into quasi- intrasensorial registration of Euclidean reconstructions and intersensorial registration with a geo-referenced orthophoto. Finally, we present reconstruction results from a real data-set and outline ideas for future work.

I/O-Efficient Computation of Water Flow Across a Terrain

DEFF Research Database (Denmark)

Arge, Lars Allan; Revsbæk, Morten; Zeh, Norbert

2010-01-01

). We present an I/O-efficient algorithm that solves this problem using O(sort(X) log (X/M) + sort(N)) I/Os, where N is the number of terrain vertices, X is the number of pits of the terrain, sort(N) is the cost of sorting N data items, and M is the size of the computer's main memory. Our algorithm...

BWR Full Integral Simulation Test (FIST) Phase II test results and TRAC-BWR model qualification

International Nuclear Information System (INIS)

Sutherland, W.A.; Alamgir, M.; Findlay, J.A.; Hwang, W.S.

1985-10-01

Eight matrix tests were conducted in the FIST Phase I. These tests investigated the large break, small break and steamline break LOCA's, as well as natural circulation and power transients. There are nine tests in Phase II of the FIST program. They include the following LOCA tests: BWR/6 LPCI line break, BWR/6 intermediate size recirculation break, and a BWR/4 large break. Steady state natural circulation tests with feedwater makeup performed at high and low pressure, and at high pressure with HPCS makeup, are included. Simulation of a transient without rod insertion, and with controlled depressurization, was performed. Also included is a simulation of the Peach Bottom turbine trip test. The final two tests simulated a failure to maintain water level during a postulated accident. A FIST program objective is to assess the TRAC code by comparisons with test data. Two post-test predictions made with TRACB04 are compared with Phase II test data in this report. These are for the BWR/6 LPCI line break LOCA, and the Peach Bottom turbine trip test simulation

Terrain and building effects on the transport of radioactive material at a nuclear site

International Nuclear Information System (INIS)

Jeong, Hyojoon; Park, Misun; Jeong, Haesun; Hwang, Wontae; Kim, Eunhan; Han, Moonhee

2014-01-01

Highlights: • This study is to quantify the building and terrain effects on the atmospheric dispersion. • Statistical methods with AERMOD-PRIME and CFD were used. • To assess the risk in nuclear power plants, terrain and building effects have to be considered. - Abstract: This study identified the terrain and building effects on the atmospheric dispersion of radioactive materials at the Wolsong Nuclear Site. To analyze the atmospheric dispersion of radioactive materials, the AERMOD-PRIME model, CFD model and meteorological data from 2010 were used. The terrain and building effects on the atmospheric dispersion of radioactive materials within a 1 km radius of the site were statistically significant. The maximum concentration of the radioactive material increased by 7 times compared to the concentration when the terrain and building effects were not considered. It was found that the terrain and building influenced the decrease in the concentration of radioactive material in a concentric circle with a 914 m radius from the center of the site. The concentration of radioactive material in a concentric circle with a 350 m radius was two-times higher than the concentration estimated at the backside of the building, which is the downwind side, without any consideration of the terrain and building effects. In consideration of the Korean situation, in which multiple nuclear reactors are built on the same nuclear site, it is necessary to evaluate the risk that may affect workers and nearby residents by reflecting the terrain and building effects

Pre-flight physical simulation test of HIMES reentry test vehicle

Science.gov (United States)

Kawaguchi, Jun'ichiro; Inatani, Yoshifumi; Yonemoto, Koichi; Hosokawa, Shigeru

ISAS is now developing a small reentry test vehicle, which is 2m long with a 1.5m wing span and weighs about 170 kg, for the purpose of exploring high angle-of-attack aerodynamic attitude control issue in supersonic and hypersonic speed. The flight test, employing 'Rockoon' launch system, is planned as a preliminary design verification for a fully reusable winged rocket named HIMES (Highly Maneuverable Experimental Space) vehicle. This paper describes the results of preflight ground test using a motion table system. This ground system test is called 'physical simulation' aimed at: (1) functional verification of side-jet system, aerodynamic surface actuators, battery and onboard avionics; and (2) guidance and control law evaluation, in total hardware-in-the-loop system. The pressure of side-jet nozzles was measured to provide exact thrust characteristics of reaction control. The dynamics of vehicle motion was calculated in real-time by the ground simulation computer.

Design, Fabrication and Testing of Carbon Fiber Reinforced Epoxy Drive Shaft for All Terrain Vehicle using Filament Winding

Directory of Open Access Journals (Sweden)

Yeshwant Nayak Suhas

2018-01-01

Full Text Available Filament winding is a composite material fabrication technique that is used to manufacture concentric hollow components. In this study Carbon/Epoxy composite drive shafts were fabricated using filament winding process with a fiber orientation of [852/±452/252]s. Carbon in the form of multifilament fibers of Tairyfil TC-33 having 3000 filaments/strand was used as reinforcement with low viscosity epoxy resin as the matrix material. The driveshaft is designed to be used in SAE Baja All Terrain Vehicle (ATV that makes use of a fully floating axle in its rear wheel drive system. The torsional strength of the shaft was tested and compared to that of an OEM steel shaft that was previously used in the ATV. Results show that the composite shaft had 8.5% higher torsional strength in comparison to the OEM steel shaft and was also lighter by 60%. Scanning electron microscopy (SEM micrographs were studied to investigate the probable failure mechanism. Delamination, matrix agglomeration, fiber pull-out and matrix cracking were the prominent failure mechanisms identified.

Reliability Testing Using the Vehicle Durability Simulator

Science.gov (United States)

2017-11-20

techniques are employed to reduce test and simulation time. Through application of these processes and techniques the reliability characteristics...remote parameter control (RPC) software. The software is specifically designed for the data collection, analysis, and simulation processes outlined in...the selection process for determining the desired runs for simulation . 4.3 Drive File Development. After the data have been reviewed and

Explosive simulants for testing explosive detection systems

Science.gov (United States)

Kury, John W.; Anderson, Brian L.

1999-09-28

Explosives simulants that include non-explosive components are disclosed that facilitate testing of equipment designed to remotely detect explosives. The simulants are non-explosive, non-hazardous materials that can be safely handled without any significant precautions. The simulants imitate real explosives in terms of mass density, effective atomic number, x-ray transmission properties, and physical form, including moldable plastics and emulsions/gels.

Simulation of Particle Fluxes at the DESY-II Test Beam Facility

International Nuclear Information System (INIS)

Schuetz, Anne

2015-05-01

In the course of this Master's thesis ''Simulation of Particle Fluxes at the DESY-II Test Beam Facility'' the test beam generation for the DESY test beam line was studied in detail and simulated with the simulation software SLIC. SLIC uses the Geant4 toolkit for realistic Monte Carlo simulations of particles passing through detector material.After discussing the physics processes relevant for the test beam generation and the principles of the beam generation itself, the software used is introduced together with a description of the functionality of the Geant4 Monte Carlo simulation. The simulation of the test beam line follows the sequence of the test beam generation. Therefore, it starts with the simulation of the beam bunch of the synchrotron accelerator DESY-II, and proceeds step by step with the single test beam line components. An additional benefit of this thesis is the provision of particle flux and trajectory maps, which make fluxes directly visible by following the particle tracks through the simulated beam line. These maps allow us to see each of the test beam line components, because flux rates and directions change rapidly at these points. They will also guide the decision for placements of future test beam line components and measurement equipment.In the end, the beam energy and its spread, and the beam rate of the final test beam in the test beam area were studied in the simulation, so that the results can be compared to the measured beam parameters. The test beam simulation of this Master's thesis will serve as a key input for future test beam line improvements.

Numerical simulation of small scale soft impact tests

International Nuclear Information System (INIS)

Varpasuo, Pentti

2008-01-01

This paper describes the small scale soft missile impact tests. The purpose of the test program is to provide data for the calibration of the numerical simulation models for impact simulation. In the experiments, both dry and fluid filled missiles are used. The tests with fluid filled missiles investigate the release speed and the droplet size of the fluid release. This data is important in quantifying the fire hazard of flammable liquid after the release. The spray release velocity and droplet size are also input data for analytical and numerical simulation of the liquid spread in the impact. The behaviour of the impact target is the second investigative goal of the test program. The response of reinforced and pre-stressed concrete walls is studied with the aid of displacement and strain monitoring. (authors)

Shape-assisted body reorientation enhances trafficability through cluttered terrain

Science.gov (United States)

Li, Chen; Pullin, Andrew; Haldane, Duncan; Fearing, Ronald; Full, Robert

2014-11-01

Many birds and fishes have slender, streamlined bodies that reduce fluid dynamic drag and allow fast and efficient locomotion. Similarly, numerous terrestrial animals run through cluttered terrain where 3-D, multi-component obstacles like grass, bushes, trees, walls, doors, and pillars also resist motion, but it is unknown whether their body shape plays a major role. Here, we challenged discoid cockroaches that possess a rounded, thin, nearly ellipsoidal body to run through tall, narrowly spaced, grass-like beams. The animals primarily rolled their body to the side to maneuver through the obstacle gaps. Reduction of body roundness by artificial shells inhibited this side roll maneuver, resulting in a lower traversal probability and a longer traversal time (P exoskeleton shell to a legged robot of a nearly cuboidal body. The rounded shell enabled the robot to use passive side rolling to maneuver through beams. To explain the mechanism, we developed a simple physics model to construct an energy landscape of the body-terrain interaction, which allowed estimation of body forces and torques exerted by the beams. Our model revealed that, by passive interaction with the terrain, a rounded body (ellipsoid) rolled more easily than an angular body (cuboid) to access energy valleys between energy barriers caused by obstacles. Our study is the first to demonstrate that a terradynamically ``streamlined'' shape can reduce terrain resistance and enhance trafficability by assisting body reorientation.

Merging a Terrain-Based Parameter and Snow Particle Counter Data for the Assessment of Snow Redistribution in the Col du Lac Blanc Area

Science.gov (United States)

Schön, Peter; Prokop, Alexander; Naaim-Bouvet, Florence; Vionnet, Vincent; Guyomarc'h, Gilbert; Heiser, Micha; Nishimura, Kouichi

2015-04-01

Wind and the associated snow drift are dominating factors determining the snow distribution and accumulation in alpine areas, resulting in a high spatial variability of snow depth that is difficult to evaluate and quantify. The terrain-based parameter Sx characterizes the degree of shelter or exposure of a grid point provided by the upwind terrain, without the computational complexity of numerical wind field models. The parameter has shown to qualitatively predict snow redistribution with good reproduction of spatial patterns. It does not, however, provide a quantitative estimate of changes in snow depths. The objective of our research was to introduce a new parameter to quantify changes in snow depths in our research area, the Col du Lac Blanc in the French Alps. The area is at an elevation of 2700 m and particularly suited for our study due to its consistently bi-modal wind directions. Our work focused on two pronounced, approximately 10 m high terrain breaks, and we worked with 1 m resolution digital snow surface models (DSM). The DSM and measured changes in snow depths were obtained with high-accuracy terrestrial laser scan (TLS) measurements. First we calculated the terrain-based parameter Sx on a digital snow surface model and correlated Sx with measured changes in snow-depths (Δ SH). Results showed that Δ SH can be approximated by Δ SHestimated = α * Sx, where α is a newly introduced parameter. The parameter α has shown to be linked to the amount of snow deposited influenced by blowing snow flux. At the Col du Lac Blanc test side, blowing snow flux is recorded with snow particle counters (SPC). Snow flux is the number of drifting snow particles per time and area. Hence, the SPC provide data about the duration and intensity of drifting snow events, two important factors not accounted for by the terrain parameter Sx. We analyse how the SPC snow flux data can be used to estimate the magnitude of the new variable parameter α . To simulate the development

Implementation and Testing of Advanced Surface Boundary Conditions Over Complex Terrain in A Semi-idealized Model

Science.gov (United States)

Li, Y.; Epifanio, C.

2017-12-01

In numerical prediction models, the interaction between the Earth's surface and the atmosphere is typically accounted for in terms of surface layer parameterizations, whose main job is to specify turbulent fluxes of heat, moisture and momentum across the lower boundary of the model domain. In the case of a domain with complex geometry, implementing the flux conditions (particularly the tensor stress condition) at the boundary can be somewhat subtle, and there has been a notable history of confusion in the CFD community over how to formulate and impose such conditions generally. In the atmospheric case, modelers have largely been able to avoid these complications, at least until recently, by assuming that the terrain resolved at typical model resolutions is fairly gentle, in the sense of having relatively shallow slopes. This in turn allows the flux conditions to be imposed as if the lower boundary were essentially flat. Unfortunately, while this flat-boundary assumption is acceptable for coarse resolutions, as grids become more refined and the geometry of the resolved terrain becomes more complex, the appproach is less justified. With this in mind, the goal of our present study is to explore the implementation and usage of the full, unapproximated version of the turbulent flux/stress conditions in atmospheric models, thus taking full account of the complex geometry of the resolved terrain. We propose to implement the conditions using a semi-idealized model developed by Epifanio (2007), in which the discretized boundary conditions are reduced to a large, sparse-matrix problem. The emphasis will be on fluxes of momentum, as the tensor nature of this flux makes the associated stress condition more difficult to impose, although the flux conditions for heat and moisture will be considered as well. With the resulotion of 90 meters, some of the results show that the typical differences between flat-boundary cases and full/stress cases are on the order of 10%, with extreme

Prototyping a robotic dental testing simulator.

Science.gov (United States)

Alemzadeh, K; Hyde, R A; Gao, J

2007-05-01

A parallel robot based on the Stewart platform is being developed to simulate jaw motion and investigate its effect on jaw function to test the wearing away of dental components such as individual teeth, crowns, bridges, full set of dentures, and implant-supported overdentures by controlling chewing motion. The current paper only describes the comparison between an alternative configuration proposed by Xu and the Stewart platform configuration. The Stewart platform was chosen as an ideal structure for simulating human mastication as it is easily assembled, has high rigidity, high load-carrying capacity, and accurate positioning capability. The kinematics and singularities of the Stewart platform have been analysed and software developed to (a) test the control algorithms/strategy of muscle movement for the six degree of freedom of mastication cycle and (b) simulate and observe various design options to be able to make the best judgement in product development. The human replica skull has been analysed and reverse engineered with further simplification before integration with the Stewart platform computer-aided design (CAD) to develop the robotic dental testing simulator. Assembly modelling of the reproduced skull was critically analysed for good occlusion in CAD environment. A pulse-width modulation (PWM) circuit plus interface was built to control position and speed of the chosen actuators. A computer numerical control (CNC) machine and wire-electro-discharge machining (wire EDM) were used to manufacture the critical parts such as lower mandible, upper maxilla, and universal joints.

An improved method of continuous LOD based on fractal theory in terrain rendering

Science.gov (United States)

Lin, Lan; Li, Lijun

2007-11-01

With the improvement of computer graphic hardware capability, the algorithm of 3D terrain rendering is going into the hot topic of real-time visualization. In order to solve conflict between the rendering speed and reality of rendering, this paper gives an improved method of terrain rendering which improves the traditional continuous level of detail technique based on fractal theory. This method proposes that the program needn't to operate the memory repeatedly to obtain different resolution terrain model, instead, obtains the fractal characteristic parameters of different region according to the movement of the viewpoint. Experimental results show that the method guarantees the authenticity of landscape, and increases the real-time 3D terrain rendering speed.

DOGWOOD RUN TERRAIN, YORK COUNTY, PA, USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data includes digital elevation models, LIDAR derived contours, LIDAR three-dimensional spot elevations and breaklines, field surveyed ground elevations and...

TERRAIN DATA CAPTURE STANDARDS, Bedford PA, USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data includes digital elevation models, LIDAR derived contours, LIDAR three-dimensional spot elevations and breaklines, field surveyed ground elevations and...

Improvement of a three-dimensional atmospheric dynamic model and examination of its performance over complex terrain

International Nuclear Information System (INIS)

Nagai, Haruyasu; Yamazawa, Hiromi

1994-11-01

A three-dimensional atmospheric dynamic model (PHYSIC) was improved and its performance was examined using the meteorological data observed at a coastal area with a complex terrain. To introduce synoptic meteorological conditions into the model, the initial and boundary conditions were improved. By this improvement, the model can predict the temporal change of wind field for more than 24 hours. Moreover, the model successfully simulates the land and sea breeze observed at Shimokita area in the summer of 1992. (author)

Geotechnical Tests on Asteroid Simulant Orgueil

Science.gov (United States)

Garcia, Alexander D'marco

2017-01-01

In the last 100 years, the global population has more than quadrupled to over seven billion people. At the same time, the demand for food and standard of living has been increasing which has amplified the global water use by nearly eight times from approximately 500 to 4000 cu km per yr from 1900 to 2010. With the increasing concern to sustain the growing population on Earth it is necessary to seek other approaches to ensure that our planet will have resources for generations to come. In recent years, the advancement of space travel and technology has allowed the idea of mining asteroids with resources closer to becoming a reality. During the duration of the internship at NASA Kennedy Space Center, several geotechnical tests were conducted on BP-1 lunar simulant and asteroid simulant Orgueil. The tests that were conducted on BP-1 was to practice utilizing the equipment that will be used on the asteroid simulant and the data from those tests will be omitted from report. Understanding the soil mechanics of asteroid simulant Orgueil will help provide basis for future technological advances and prepare scientists for the conditions they may encounter when mining asteroids becomes reality in the distant future. Distinct tests were conducted to determine grain size distribution, unconsolidated density, and maximum density. Once the basic properties are known, the asteroid simulant will be altered to different levels of compaction using a vibrator table to see how compaction affects the density. After different intervals of vibration compaction, a miniature vane shear test will be conducted. Laboratory vane shear testing is a reliable tool to investigate strength anisotropy in the vertical and horizontal directions of a very soft to stiff saturated fine-grained clayey soil. This test will provide us with a rapid determination of the shear strength on the undisturbed compacted regolith. The results of these tests will shed light on how much torque is necessary to drill

Walking on uneven terrain with a powered ankle prosthesis: A preliminary assessment.

Science.gov (United States)

Shultz, Amanda H; Lawson, Brian E; Goldfarb, Michael

2015-01-01

A successful walking gait with a powered prosthesis depends heavily on proper timing of power delivery, or push-off. This paper describes a control approach which provides improved walking on uneven terrain relative to previous work intended for use on even (level) terrain. This approach is motivated by an initial healthy subject study which demonstrated less variation in sagittal plane shank angle than sagittal plane ankle angle when walking on uneven terrain relative to even terrain. The latter therefore replaces the former as the control signal used to initiate push-off in the powered prosthesis described herein. The authors demonstrate improvement in consistency for several gait characteristics, relative to healthy, as well as controller characteristics with the new control approach, including a 50% improvement in the consistency of the percentage of stride at which push-off is initiated.

Performance and evaluation of a coupled prognostic model TAPM over a mountainous complex terrain industrial area

Science.gov (United States)

Matthaios, Vasileios N.; Triantafyllou, Athanasios G.; Albanis, Triantafyllos A.; Sakkas, Vasileios; Garas, Stelios

2018-05-01

Atmospheric modeling is considered an important tool with several applications such as prediction of air pollution levels, air quality management, and environmental impact assessment studies. Therefore, evaluation studies must be continuously made, in order to improve the accuracy and the approaches of the air quality models. In the present work, an attempt is made to examine the air pollution model (TAPM) efficiency in simulating the surface meteorology, as well as the SO2 concentrations in a mountainous complex terrain industrial area. Three configurations under different circumstances, firstly with default datasets, secondly with data assimilation, and thirdly with updated land use, ran in order to investigate the surface meteorology for a 3-year period (2009-2011) and one configuration applied to predict SO2 concentration levels for the year of 2011.The modeled hourly averaged meteorological and SO2 concentration values were statistically compared with those from five monitoring stations across the domain to evaluate the model's performance. Statistical measures showed that the surface temperature and relative humidity are predicted well in all three simulations, with index of agreement (IOA) higher than 0.94 and 0.70 correspondingly, in all monitoring sites, while an overprediction of extreme low temperature values is noted, with mountain altitudes to have an important role. However, the results also showed that the model's performance is related to the configuration regarding the wind. TAPM default dataset predicted better the wind variables in the center of the simulation than in the boundaries, while improvement in the boundary horizontal winds implied the performance of TAPM with updated land use. TAPM assimilation predicted the wind variables fairly good in the whole domain with IOA higher than 0.83 for the wind speed and higher than 0.85 for the horizontal wind components. Finally, the SO2 concentrations were assessed by the model with IOA varied from 0

Simulated hail impact testing of photovoltaic solar panels

Science.gov (United States)

Moore, D.; Wilson, A.; Ross, R.

1978-01-01

Techniques used to simulate and study the effect of hail on photovoltaic solar panels are described. Simulated hail stones (frozen ice spheres projected at terminal velocity) or steel balls were applied by air guns, gravity drop, or static loading. Tests with simulated hail and steel balls yielded different results. The impact strength of 10 commercially available flat-plate photovoltaic modules was tested. It was found that none of the six panel designs incorporating clear potting silicone material as the outermost layer remained undamaged by 1-in. simulated hailstones, while a photovoltaic module equipped with a 0.188-in.-thick acrylic cover sheet would be able to withstand the impact of a 2-in.-diameter hailstone.

AAN Tactical Roles in Complex Urban Terrain

National Research Council Canada - National Science Library

Funkhouser, Anthony

1998-01-01

.... The infantryman will assume the responsibility for tasks such as mobility. However, many experts predict the future battlefields will consist of complex urban terrain where much of the world population is occupying...

Robot navigation in unknown terrains: Introductory survey of non-heuristic algorithms

Energy Technology Data Exchange (ETDEWEB)

Rao, N.S.V. [Oak Ridge National Lab., TN (US); Kareti, S.; Shi, Weimin [Old Dominion Univ., Norfolk, VA (US). Dept. of Computer Science; Iyengar, S.S. [Louisiana State Univ., Baton Rouge, LA (US). Dept. of Computer Science

1993-07-01

A formal framework for navigating a robot in a geometric terrain by an unknown set of obstacles is considered. Here the terrain model is not a priori known, but the robot is equipped with a sensor system (vision or touch) employed for the purpose of navigation. The focus is restricted to the non-heuristic algorithms which can be theoretically shown to be correct within a given framework of models for the robot, terrain and sensor system. These formulations, although abstract and simplified compared to real-life scenarios, provide foundations for practical systems by highlighting the underlying critical issues. First, the authors consider the algorithms that are shown to navigate correctly without much consideration given to the performance parameters such as distance traversed, etc. Second, they consider non-heuristic algorithms that guarantee bounds on the distance traversed or the ratio of the distance traversed to the shortest path length (computed if the terrain model is known). Then they consider the navigation of robots with very limited computational capabilities such as finite automata, etc.

The Mysteries and Curiosities of Mars: A Tour of Unusual and Unexplained Terrains

Science.gov (United States)

Kerber, L.

2017-12-01

The large amount of data available from orbiting satellites around Mars has provided a wealth of information about the Martian surface and geological history. The published literature tends to focus on regions of Mars for which there are ready explanations; however, many regions of Mars remain mysterious. In this contribution, we present some of the strangest and least explained terrains on Mars: The Taffy Terrain: This complex terrain, consisting of swirling layers with variably sized bands, is present mostly at the bottom of Hellas Basin, but versions of it can also be found on the floor of Melas Chasma and in the Medusae Fossae Formation near Apollinaris Sulci. While little has been written about the taffy terrain, hypotheses include "glacial features" and salt domes. The taffy terrain bears some resemblance to submarine salt domes in the Gulf of Mexico, glacial deposits with mixed ash and ice in Iceland, or chalk formations in Egypt's White Desert. The Fishscale Terrain: At the northern edge of Lucus Planum, the friable Medusae Fossae Formation transitions into a chaos-like terrain with hundreds of mesas forming a pattern like the scales of a fish. While chaos terrains are mysterious in general, this morphologically fresh, near-equatorial chaos is especially unusual. Polygonal Ridges in Gordii Dorsum: Also a part of the Medusae Fossae Formation, the ridges in Gordii Dorsum represent a negative image of the fishscale terrain—a intricate lattice of slender black ridges. These are thought to form via the embayment of the fishscale terrain with lava and the subsequent erosion of the original mesas. Horseshoe Features: These geomorphological features look like inverted barchan dunes, but they are actually pits eroded into the surface of the Medusae Fossae Formation. Channels surrounding Elysium Mons: These channel systems are among the most complex on Mars, but they appear on a young Amazonian lava surface. The channels cut through topography, anastomose, and

Improving SAR Automatic Target Recognition Models with Transfer Learning from Simulated Data

DEFF Research Database (Denmark)

Malmgren-Hansen, David; Kusk, Anders; Dall, Jørgen

2017-01-01

SAR images. The simulated data set is obtained by adding a simulated object radar reflectivity to a terrain model of individual point scatters, prior to focusing. Our results show that a Convolutional Neural Network (Convnet) pretrained on simulated data has a great advantage over a Convnet trained...

Merging field mapping and numerical simulation to interpret the lithofacies variations from unsteady pyroclastic density currents on uneven terrain: The case of La Fossa di Vulcano (Aeolian Islands, Italy)

Science.gov (United States)

Doronzo, Domenico M.; Dellino, Pierfrancesco; Sulpizio, Roberto; Lucchi, Federico

2017-01-01

In order to obtain results from computer simulations of explosive volcanic eruptions, one either needs a statistical approach to test a wide range of initial and boundary conditions, or needs using a well-constrained field case study via stratigraphy. Here we followed the second approach, using data obtained from field mapping of the Grotta dei Palizzi 2 pyroclastic deposits (Vulcano Island, Italy) as input for numerical modeling. This case study deals with impulsive phreatomagmatic explosions of La Fossa Cone that generated ash-rich pyroclastic density currents, interacting with the topographic high of the La Fossa Caldera rim. One of the simplifications in dealing with well-sorted ash (one particle size in the model) is to highlight the topographic effects on the same pyroclastic material in an unsteady current. We demonstrate that by merging field data with 3D numerical simulation results it is possible to see key details of the dynamical current-terrain interaction, and to interpret the lithofacies variations of the associated deposits as a function of topography-induced sedimentation (settling) rate. Results suggest that a value of the sedimentation rate lower than 5 kg/m2 s at the bed load can still be sheared by the overlying current, producing tractional structures (laminae) in the deposits. Instead, a sedimentation rate higher than that threshold can preclude the formation of tractional structures, producing thicker massive deposits. We think that the approach used in this study could be applied to other case studies (both for active and ancient volcanoes) to confirm or refine such threshold value of the sedimentation rate, which is to be considered as an upper value as for the limitations of the numerical model.

DCS TERRAIN SUBMISSION FOR PUTNAM COUNTY, FL

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describe the digital topographic data that were used to create...

DCS Terrain Submission for Dawes County, NE

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, CITY OF DALLAS, DALLAS COUNTY, TEXAS

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN, Priest Lake, Bonner County, Idaho USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain Submission for LeFlore, OK

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain Submission for Mason County, KY

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that were used to create...

DCS TERRAIN SUBMISSION FOR VOLUSIA COUNTY, FL

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describe the digital topographic data that were used to create...

DCS Terrain Submission for Cass County, MO

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain Submission for Bark River PMR

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain Submission for Lee County MS

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain for Greer County, Oklahoma, USA

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain Submission for Angelina County, TX

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

TERRAIN DATA, CITY OF CARSON CITY, NV

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describe the digital topographic data that were used to create...

DCS Terrain Submission for Fulton County, IN

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain Submission for Miami County, IN

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain Submittal for Socorro County NM

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describe the digital topographic data that were used to create...

Digital Terrain Submittal for Duval County, FL

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

DCS TERRAIN SUBMISSION FOR KNOX COUNTY, TN

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describe the digital topographic data that were used to create...

DCS Terrain Submission for Cass County, TX

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain Submission for Lancaster County, NE

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain Submission for Benton County, AR

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describe the digital topographic data that were used to create...

DCS Terrain Submission for Pike County, KY

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that were used to create...

DCS Terrain Submission for Winston County, AL

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain Submission for Chemung County, NY

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain Submission for Chippewa County, Wisconsin

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

DCS TERRAIN SUBMISSION FOR SHELBY COUNTY, TN

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describe the digital topographic data that were used to create...

DCS Terrain Submission for Albany County NY

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describe the digital topographic data that were used to create...

DCS Terrain Submission for Gunnison County, CO

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain Submission for Lewis County, KY

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that were used to create...

DCS Terrain Submission for Lake County, Montana

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain Submission for Missoula County,Montana

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain Submission for Chariton County, MO

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

DCS Terrain Submission for Lagrange County, IN

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

DCS TERRAIN Submission for STEARNS COUNTY, MN

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

Penitentes as the Origin of the Bladed Terrain of Tartarus Dorsa on Pluto

Science.gov (United States)

Moores, John E.; Smith, Christina L.; Toigo, Anthony D.; Guzewich, Scott D.

2017-01-01

Penitentes are snow and ice features formed by erosion that, on Earth, are characterized by bowl-shaped depressions several tens of centimetres across, whose edges grade into spires up to several metres tall. Penitentes have been suggested as an explanation for anomalous radar data on Europa, but until now no penitentes have been identified conclusively on planetary bodies other than Earth. Regular ridges with spacings of 3,000 to 5,000 metres and depths of about 500 metres with morphologies that resemble penitentes have been observed by the New Horizons spacecraft in the Tartarus Dorsa region of Pluto (220 deg -250 deg E, 0 deg -20 deg N). Here we report simulations, based upon a recent model representing conditions on Pluto in which deepening penitentes reproduce both the tri-modal (north-south, east-west and northeast-southwest) orientation and the spacing of the ridges of this bladed terrain. At present, these penitentes deepen by approximately one centimetre per orbital cycle and grow only during periods of relatively high atmospheric pressure, suggesting a formation timescale of several tens of millions of years, consistent with crater ages. This timescale implies that the penitentes formed from initial topographic variations of no more than a few tens of metres, consistent with Plutos youngest terrains.

Simulation of a force on force exercise

International Nuclear Information System (INIS)

Terhune, R.; Van Slyke, D.; Sheppard, T.; Brandrup, M.

1988-01-01

The Security Exercise Evaluation System (SEES) is under development for use in planning Force on Force exercises and as an aid in post-exercise evaluation. This study is part of the development cycle where the simulation results are compared to field data to provide guidance for further development of the model. SEES is an event-driven stochastic computer program simulating individual movement and combat within an urban terrain environment. The simulator models the physics of movement, line of sight, and weapon effects. It relies on the controllers to provide all knowledge of security tactics, which are entered by the controllers during the simulation using interactive color graphic workstations. They are able to develop, modify and implement plans promptly as the simulator maintains real time. This paper reports on how SEES will be used to develop an intrusion plan, test the security response tactics and develop observer logistics. A Force on Force field exercise will then be executed to follow the plan with observations recorded. An analysis is made by first comparing the plan and events of the simulation with the field exercise, modifying the simulation plan to match the actual field exercise, and then running the simulation to develop a distribution of possible outcomes