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1

Entry, Descent and Landing Systems Analysis Study: Phase 1 Report  

NASA Technical Reports Server (NTRS)

NASA senior management commissioned the Entry, Descent and Landing Systems Analysis (EDL-SA) Study in 2008 to identify and roadmap the Entry, Descent and Landing (EDL) technology investments that the agency needed to make in order to successfully land large payloads at Mars for both robotic and human-scale missions. This paper summarizes the motivation, approach and top-level results from Year 1 of the study, which focused on landing 10-50 mt on Mars, but also included a trade study of the best advanced parachute design for increasing the landed payloads within the EDL architecture of the Mars Science Laboratory (MSL) mission

DwyerCianciolo, Alicia M.; Davis, Jody L.; Komar, David R.; Munk, Michelle M.; Samareh, Jamshid A.; Powell, Richard W.; Shidner, Jeremy D.; Stanley, Douglas O.; Wilhite, Alan W.; Kinney, David J.; McGuire, M. Kathleen; Arnold, James O.; Howard, Austin R.; Sostaric, Ronald R.; Studak, Joseph W.; Zumwalt, Carlie H.; Llama, Eduardo G.; Casoliva, Jordi; Ivanov, Mark C.; Clark, Ian; Sengupta, Anita

2010-01-01

2

The Land Analysis System (LAS) for multispectral image processing  

USGS Publications Warehouse

The Land Analysis System (LAS) is an interactive software system available in the public domain for the analysis, display, and management of multispectral and other digital image data. LAS provides over 240 applications functions and utilities, a flexible user interface, complete online and hard-copy documentation, extensive image-data file management, reformatting, conversion utilities, and high-level device independent access to image display hardware. The authors summarize the capabilities of the current release of LAS (version 4.0) and discuss plans for future development. Particular emphasis is given to the issue of system portability and the importance of removing and/or isolating hardware and software dependencies.

Wharton, S. W.; Lu, Y. C.; Quirk, Bruce K.; Oleson, Lyndon R.; Newcomer, J. A.; Irani, Frederick M.

1988-01-01

3

Analysis of dynamic response requirements for GNSS landing systems  

Microsoft Academic Search

An important issue in the development of future Global Navigation Satellite System (GNSS) Landing Systems (GLSs) is the dynamic response characteristics of GLS airborne equipment. To be compatible with existing airborne systems which use the Instrument Landing System (ILS), it is desirable for the dynamic properties of the GLS guidance signal to be equivalent to ILS. Specific concerns include dynamic

Gary A. McGraw

1998-01-01

4

Entry, Descent and Landing Systems Analysis Study: Phase 2 Report on Exploration Feed-Forward Systems  

NASA Technical Reports Server (NTRS)

NASA senior management commissioned the Entry, Descent and Landing Systems Analysis (EDL-SA) Study in 2008 to identify and roadmap the Entry, Descent and Landing (EDL) technology investments that the agency needed to successfully land large payloads at Mars for both robotic and human-scale missions. Year 1 of the study focused on technologies required for Exploration-class missions to land payloads of 10 to 50 t. Inflatable decelerators, rigid aeroshell and supersonic retro-propulsion emerged as the top candidate technologies. In Year 2 of the study, low TRL technologies identified in Year 1, inflatables aeroshells and supersonic retropropulsion, were combined to create a demonstration precursor robotic mission. This part of the EDL-SA Year 2 effort, called Exploration Feed Forward (EFF), took much of the systems analysis simulation and component model development from Year 1 to the next level of detail.

Dwyer Ciancolo, Alicia M.; Davis, Jody L.; Engelund, Walter C.; Komar, D. R.; Queen, Eric M.; Samareh, Jamshid A.; Way, David W.; Zang, Thomas A.; Murch, Jeff G.; Krizan, Shawn A.; Olds, Aaron D.; Powell, Richard W.; Shidner, Jeremy D.; Kinney, Daivd J.; McGuire, M. Kathleen; Arnold, James O.; Covington, M. Alan; Sostaric, Ronald R.; Zumwalt, Carlie H.; Llama, Eduardo G.

2011-01-01

5

Overview of the NASA Entry, Descent and Landing Systems Analysis Study  

NASA Technical Reports Server (NTRS)

NASA senior management commissioned the Entry, Descent and Landing Systems Analysis (EDL-SA) Study in 2008 to identify and roadmap the Entry, Descent and Landing (EDL) technology investments that the agency needed to make in order to successfully land large payloads at Mars for both robotic and human-scale missions. This paper summarizes the approach and top-level results from Year 1 of the Study, which focused on landing 10-50 mt on Mars, but also included a trade study of the best advanced parachute design for increasing the landed payloads within the EDL architecture of the Mars Science Laboratory (MSL) mission.

Zang, Thomas A.; Dwyer-Cianciolo, Alicia M.; Kinney, David J.; Howard, Austin R.; Chen, George T.; Ivanov, Mark C.; Sostaric, Ronald R.; Westhelle, Carlos H.

2010-01-01

6

Entry, Descent and Landing Systems Analysis: Exploration Feed Forward Internal Peer Review Slide Package  

NASA Technical Reports Server (NTRS)

NASA senior management commissioned the Entry, Descent and Landing Systems Analysis (EDL-SA) Study in 2008 to identify and roadmap the Entry, Descent and Landing (EDL) technology investments that the agency needed to successfully land large payloads at Mars for both robotic and human-scale missions. Year 1 of the study focused on technologies required for Exploration-class missions to land payloads of 10 to 50 mt. Inflatable decelerators, rigid aeroshell and supersonic retro-propulsion emerged as the top candidate technologies. In Year 2 of the study, low TRL technologies identified in Year 1, inflatables aeroshells and supersonic retropropulsion, were combined to create a demonstration precursor robotic mission. This part of the EDL-SA Year 2 effort, called Exploration Feed Forward (EFF), took much of the systems analysis simulation and component model development from Year 1 to the next level of detail.

Dwyer Cianciolo, Alicia M. (Editor)

2011-01-01

7

Entry, Descent and Landing Systems Analysis: Exploration Class Simulation Overview and Results  

NASA Technical Reports Server (NTRS)

NASA senior management commissioned the Entry, Descent and Landing Systems Analysis (EDL-SA) Study in 2008 to identify and roadmap the Entry, Descent and Landing (EDL) technology investments that the agency needed to make in order to successfully land large payloads at Mars for both robotic and exploration or human-scale missions. The year one exploration class mission activity considered technologies capable of delivering a 40-mt payload. This paper provides an overview of the exploration class mission study, including technologies considered, models developed and initial simulation results from the EDL-SA year one effort.

DwyerCianciolo, Alicia M.; Davis, Jody L.; Shidner, Jeremy D.; Powell, Richard W.

2010-01-01

8

Heave-pitch-roll analysis and testing of air cushion landing systems  

NASA Technical Reports Server (NTRS)

The analytical tools (analysis and computer simulation) needed to explain and predict the dynamic operation of air cushion landing systems (ACLS) is described. The following tasks were performed: the development of improved analytical models for the fan and the trunk; formulation of a heave pitch roll analysis for the complete ACLS; development of a general purpose computer simulation to evaluate landing and taxi performance of an ACLS equipped aircraft; and the verification and refinement of the analysis by comparison with test data obtained through lab testing of a prototype cushion. Demonstration of simulation capabilities through typical landing and taxi simulation of an ACLS aircraft are given. Initial results show that fan dynamics have a major effect on system performance. Comparison with lab test data (zero forward speed) indicates that the analysis can predict most of the key static and dynamic parameters (pressure, deflection, acceleration, etc.) within a margin of a 10 to 25 percent.

Boghani, A. B.; Captain, K. M.; Wormley, D. N.

1978-01-01

9

Title : "SMALL Savannah: An Information System for the integrated analysis of land use change in the Far North Cameroon"  

E-print Network

Title : "SMALL Savannah: An Information System for the integrated analysis of land use change and sharing on natural resources and land use. The case study of the far North region of Cameroon shows competition among land uses, more conflicts between actors and increasing poverty. The model developed

Hille, Sander

10

AIR LAND WATER ANALYSIS SYSTEM (ALEAS): A MULTI-MEDIA MODEL FOR TOXIC SUBSTANCES  

EPA Science Inventory

The Air Land Water Analysis System (ALWAS) is a multi-media environmental model for describing the atmospheric dispersion of toxicants, the surface runoff of deposited toxicants, and the subsequent fate of these materials in surface water bodies. ALWAS dipicts the spatial and tem...

11

Microwave Landing System  

Microsoft Academic Search

The National Microwave Landing Systems (MLS) program is a joint DOT\\/DOD\\/NASA effort to implement a common civil\\/military precision landing system to replace the current Instrument Landing System (ILS). The MLS will be capable of providing precision landing guidance down to Category III minimum while allowing for complex approach paths in both the horizontal and vertical planes. The system is based

Thomas E. Evans

1986-01-01

12

Multidisciplinary Tool for Systems Analysis of Planetary Entry, Descent, and Landing  

NASA Technical Reports Server (NTRS)

Systems analysis of a planetary entry (SAPE), descent, and landing (EDL) is a multidisciplinary activity in nature. SAPE improves the performance of the systems analysis team by automating and streamlining the process, and this improvement can reduce the errors that stem from manual data transfer among discipline experts. SAPE is a multidisciplinary tool for systems analysis of planetary EDL for Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Titan. It performs EDL systems analysis for any planet, operates cross-platform (i.e., Windows, Mac, and Linux operating systems), uses existing software components and open-source software to avoid software licensing issues, performs low-fidelity systems analysis in one hour on a computer that is comparable to an average laptop, and keeps discipline experts in the analysis loop. SAPE uses Python, a platform-independent, open-source language, for integration and for the user interface. Development has relied heavily on the object-oriented programming capabilities that are available in Python. Modules are provided to interface with commercial and government off-the-shelf software components (e.g., thermal protection systems and finite-element analysis). SAPE currently includes the following analysis modules: geometry, trajectory, aerodynamics, aerothermal, thermal protection system, and interface for structural sizing.

Samareh, Jamshid A.

2011-01-01

13

Air cushion landing system  

NASA Technical Reports Server (NTRS)

Static and dynamic performance of air cushion landing system is simulated in computer program that treats four primary ACLS subsystems: fan, feeding system, trunk, and cushion. Configuration of systems is sufficiently general to represent variety of practical designs.

Boghami, K. M.; Captain, K. M.; Fish, R. B.

1978-01-01

14

Instrument Landing Systems  

Microsoft Academic Search

A historical background of instrumental approach and landing equipment for aircraft is given beginning with post-World War I efforts of J. D. Doolittle and emphasizing military-civil standardization efforts that began in 1948 and are continuing. The inadequacies of the current Instrument Landing System (ILS) are detailed and the various efforts of special committees to define an eventual replacement system are

L. Sanders

1973-01-01

15

Interfacing geographic information systems and remote sensing for rural land-use analysis  

NASA Technical Reports Server (NTRS)

Recent advances in computer-based geographic information systems (GISs) are briefly reviewed, with an emphasis on the incorporation of remote-sensing data in GISs for rural applications. Topics addressed include sampling procedures for rural land-use analyses; GIS-based mapping of agricultural land use and productivity; remote sensing of land use and agricultural, forest, rangeland, and water resources; monitoring the dynamics of irrigation agriculture; GIS methods for detecting changes in land use over time; and the development of land-use modeling strategies.

Nellis, M. Duane; Lulla, Kamlesh; Jensen, John

1990-01-01

16

Land system change and food security: towards multi-scale land system solutions?  

PubMed Central

Land system changes are central to the food security challenge. Land system science can contribute to sustainable solutions by an integrated analysis of land availability and the assessment of the tradeoffs associated with agricultural expansion and land use intensification. A land system perspective requires local studies of production systems to be contextualised in a regional and global context, while global assessments should be confronted with local realities. Understanding of land governance structures will help to support the development of land use policies and tenure systems that assist in designing more sustainable ways of intensification. Novel land systems should be designed that are adapted to the local context and framed within the global socio-ecological system. Such land systems should explicitly account for the role of land governance as a primary driver of land system change and food production. PMID:24143158

Verburg, Peter H; Mertz, Ole; Erb, Karl-Heinz; Haberl, Helmut; Wu, Wenbin

2013-01-01

17

Analysis and design of a capsule landing system and surface vehicle control system for Mars exploration  

NASA Technical Reports Server (NTRS)

A number of problems related to the design, construction and evaluation of an autonomous roving planetary vehicle and its control and operating systems intended for an unmanned exploration of Mars are studied. Vehicle configuration, dynamics, control, systems and propulsion; systems analysis; terrain sensing and modeling and path selection; and chemical analysis of samples are included.

1974-01-01

18

Study of USGS/NASA land use classification system. [computer analysis from LANDSAT data  

NASA Technical Reports Server (NTRS)

The results of a computer mapping project using LANDSAT data and the USGS/NASA land use classification system are summarized. During the computer mapping portion of the project, accuracies of 67 percent to 79 percent were achieved using Level II of the classification system and a 4,000 acre test site centered on Douglasville, Georgia. Analysis of response to a questionaire circulated to actual and potential LANDSAT data users reveals several important findings: (1) there is a substantial desire for additional information related to LANDSAT capabilities; (2) a majority of the respondents feel computer mapping from LANDSAT data could aid present or future projects; and (3) the costs of computer mapping are substantially less than those of other methods.

Spann, G. W.

1975-01-01

19

Analysis and design of a capsule landing system and surface vehicle control system for Mars exploration  

NASA Technical Reports Server (NTRS)

Problems related to the design and control of a mobile planetary vehicle to implement a systematic plan for the exploration of Mars are reported. Problem areas include: vehicle configuration, control, dynamics, systems and propulsion; systems analysis, terrain modeling and path selection; and chemical analysis of specimens. These tasks are summarized: vehicle model design, mathematical model of vehicle dynamics, experimental vehicle dynamics, obstacle negotiation, electrochemical controls, remote control, collapsibility and deployment, construction of a wheel tester, wheel analysis, payload design, system design optimization, effect of design assumptions, accessory optimal design, on-board computer subsystem, laser range measurement, discrete obstacle detection, obstacle detection systems, terrain modeling, path selection system simulation and evaluation, gas chromatograph/mass spectrometer system concepts, and chromatograph model evaluation and improvement.

Frederick, D. K.; Lashmet, P. K.; Sandor, G. N.; Shen, C. N.; Smith, E. V.; Yerazunis, S. W.

1973-01-01

20

Analysis and design of a capsule landing system and surface vehicle control system for Mars exporation  

NASA Technical Reports Server (NTRS)

The problems related to the design and control of a mobile planetary vehicle to implement a systematic plan for the exploration of Mars were investigated. Problem areas receiving attention include: vehicle configuration, control, dynamics, systems and propulsion; systems analysis; navigation, terrain modeling and path selection; and chemical analysis of specimens. The following specific tasks were studied: vehicle model design, mathematical modeling of dynamic vehicle, experimental vehicle dynamics, obstacle negotiation, electromechanical controls, collapsibility and deployment, construction of a wheel tester, wheel analysis, payload design, system design optimization, effect of design assumptions, accessory optimal design, on-board computer subsystem, laser range measurement, discrete obstacle detection, obstacle detection systems, terrain modeling, path selection system simulation and evaluation, gas chromatograph/mass spectrometer system concepts, chromatograph model evaluation and improvement and transport parameter evaluation.

Frederick, D. K.; Lashmet, P. K.; Sandor, G. N.; Shen, C. N.; Smith, E. J.; Yerazunis, S. W.

1972-01-01

21

Analysis and design of a capsule landing system and surface vehicle control system for Mars exploration  

NASA Technical Reports Server (NTRS)

Investigation of problems related to the design and control of a mobile planetary vehicle to implement a systematic plan for the exploration of Mars has been undertaken. Problem areas receiving attention include: vehicle configuration, control, dynamics, systems and propulsion; systems analysis; terrain modeling and path selection; and chemical analysis of specimens. The following specific tasks have been under study: vehicle model design, mathematical modeling of a dynamic vehicle, experimental vehicle dynamics, obstacle negotiation, electromechanical controls, collapsibility and deployment, construction of a wheel tester, wheel analysis, payload design, system design optimization, effect of design assumptions, accessory optimal design, on-board computer sybsystem, laser range measurement, discrete obstacle detection, obstacle detection systems, terrain modeling, path selection system simulation and evaluation, gas chromatograph/mass spectrometer system concepts, chromatograph model evaluation and improvement.

Frederick, D. K.; Lashmet, P. K.; Sandor, G. N.; Shen, C. N.; Smith, E. J.; Yerazunis, S. W.

1972-01-01

22

Global Land Information System  

USGS Publications Warehouse

The Global Land Information System (GLIS) is a World Wide Web-based query tool developed by the U.S. Geological Survey (USGS) to provide data and information about the Earth's land surface. Examples of holdings available through the GLIS include cartographic data, topographic data, soils data, aerial photographs, and satellite images from various agencies and cooperators located around the world. Both hard copy and digital data collections are represented in the GLIS, and preview images are available for millions of the products in the system.

U.S. Geological Survey

1999-01-01

23

LandCaRe DSS--an interactive decision support system for climate change impact assessment and the analysis of potential agricultural land use adaptation strategies.  

PubMed

Decision support to develop viable climate change adaptation strategies for agriculture and regional land use management encompasses a wide range of options and issues. Up to now, only a few suitable tools and methods have existed for farmers and regional stakeholders that support the process of decision-making in this field. The interactive model-based spatial information and decision support system LandCaRe DSS attempts to close the existing methodical gap. This system supports interactive spatial scenario simulations, multi-ensemble and multi-model simulations at the regional scale, as well as the complex impact assessment of potential land use adaptation strategies at the local scale. The system is connected to a local geo-database and via the internet to a climate data server. LandCaRe DSS uses a multitude of scale-specific ecological impact models, which are linked in various ways. At the local scale (farm scale), biophysical models are directly coupled with a farm economy calculator. New or alternative simulation models can easily be added, thanks to the innovative architecture and design of the DSS. Scenario simulations can be conducted with a reasonable amount of effort. The interactive LandCaRe DSS prototype also offers a variety of data analysis and visualisation tools, a help system for users and a farmer information system for climate adaptation in agriculture. This paper presents the theoretical background, the conceptual framework, and the structure and methodology behind LandCaRe DSS. Scenario studies at the regional and local scale for the two Eastern German regions of Uckermark (dry lowlands, 2600 km(2)) and Weißeritz (humid mountain area, 400 km(2)) were conducted in close cooperation with stakeholders to test the functionality of the DSS prototype. The system is gradually being transformed into a web version (http://www.landcare-dss.de) to ensure the broadest possible distribution of LandCaRe DSS to the public. The system will be continuously developed, updated and used in different research projects and as a learning and knowledge-sharing tool for students. The main objective of LandCaRe DSS is to provide information on the complex long-term impacts of climate change and on potential management options for adaptation by answering "what-if" type questions. PMID:23582740

Wenkel, Karl-Otto; Berg, Michael; Mirschel, Wilfried; Wieland, Ralf; Nendel, Claas; Köstner, Barbara

2013-09-01

24

Analysis and design of a capsule landing system and surface vehicle control system for Mars exploration  

NASA Technical Reports Server (NTRS)

Investigation of problems related to control of a mobile planetary vehicle according to a systematic plan for the exploration of Mars has been undertaken. Problem areas receiving attention include: (1) overall systems analysis; (2) vehicle configuration and dynamics; (3) toroidal wheel design and evaluation; (4) on-board navigation systems; (5) satellite-vehicle navigation systems; (6) obstacle detection systems; (7) terrain sensing, interpretation and modeling; (8) computer simulation of terrain sensor-path selection systems; and (9) chromatographic systems design concept studies. The specific tasks which have been undertaken are defined and the progress which has been achieved during the period July 1, 1971 to December 31, 1971 is summarized.

Frederick, D. K.; Lashmet, P. K.; Sandor, G. N.; Shen, C. N.; Smith, E. J.; Yerazunis, S. W.

1971-01-01

25

Parametric Mass Modeling for Mars Entry, Descent and Landing System Analysis Study  

NASA Technical Reports Server (NTRS)

This paper provides an overview of the parametric mass models used for the Entry, Descent, and Landing Systems Analysis study conducted by NASA in FY2009-2010. The study examined eight unique exploration class architectures that included elements such as a rigid mid-L/D aeroshell, a lifting hypersonic inflatable decelerator, a drag supersonic inflatable decelerator, a lifting supersonic inflatable decelerator implemented with a skirt, and subsonic/supersonic retro-propulsion. Parametric models used in this study relate the component mass to vehicle dimensions and mission key environmental parameters such as maximum deceleration and total heat load. The use of a parametric mass model allows the simultaneous optimization of trajectory and mass sizing parameters.

Samareh, Jamshid A.; Komar, D. R.

2011-01-01

26

Aircraft landing gear systems  

NASA Technical Reports Server (NTRS)

Topics presented include the laboratory simulation of landing gear pitch-plane dynamics, a summary of recent aircraft/ground vehicle friction measurement tests, some recent aircraft tire thermal studies, and an evaluation of critical speeds in high-speed aircraft. Also presented are a review of NASA antiskid braking research, titanium matrix composite landing gear development, the current methods and perspective of aircraft flotation analysis, the flow rate and trajectory of water spray produced by an aircraft tire, and spin-up studies of the Space Shuttle Orbiter main gear tire.

Tanner, John A. (editor)

1990-01-01

27

Analysis of Summer Thunderstorms in Central Alabama Using the NASA Land Information System  

NASA Technical Reports Server (NTRS)

Forecasters have difficulty predicting "random" afternoon thunderstorms during the summer months. Differences in soil characteristics could be a contributing factor for storms. The NASA Land Information System (LIS) may assist forecasters in predicting summer convection by identifying boundaries in land characteristics. This project identified case dates during the summer of 2009 by analyzing synoptic weather maps, radar, and satellite data to look for weak atmospheric forcing and disorganized convective development. Boundaries in land characteristics that may have lead to convective initiation in central Alabama were then identified using LIS.

James, Robert; Case, Jonathan; Molthan, Andrew; Jedloved, Gary

2010-01-01

28

Analysis of Summertime Convective Initiation in Central Alabama Using the Land Information System  

NASA Technical Reports Server (NTRS)

During the summer months in the southeastern United States, convective initiation presents a frequent challenge to operational forecasters. Thunderstorm development has traditionally been referred to as random due to their disorganized, sporadic appearance and lack of atmospheric forcing. Horizontal variations in land surface characteristics such as soil moisture, soil type, land and vegetation cover could possibly be a focus mechanism for afternoon convection during the summer months. The NASA Land Information System (LIS) provides a stand-alone land surface modeling framework that incorporates these varying soil and vegetation properties, antecedent precipitation, and atmospheric forcing to represent the soil state at high resolution. The use of LIS as a diagnostic tool may help forecasters to identify boundaries in land surface characteristics that could correlate to favored regions of convection initiation. The NASA Shortterm Prediction Research and Transition (SPoRT) team has been collaborating with the National Weather Service Office in Birmingham, AL to help incorporate LIS products into their operational forecasting methods. This paper highlights selected convective case dates from summer 2009 when synoptic forcing was weak, and identifies any boundaries in land surface characteristics that may have contributed to convective initiation. The LIS output depicts the effects of increased sensible heat flux from urban areas on the development of convection, as well as convection along gradients in land surface characteristics and surface sensible and latent heat fluxes. These features may promote mesoscale circulations and/or feedback processes that can either enhance or inhibit convection. With this output previously unavailable to operational forecasters, LIS provides a new tool to forecasters in order to help eliminate the randomness of summertime convective initiation.

James, Robert S.; Case, Jonathan L.; Molthan, Andrew L.; Jedlovec, Gary J.

2011-01-01

29

Sensitivity analysis of helicopter IMC decelerating steep approach and landing performance to navigation system parameters. [Instrument Meteorological Conditions  

NASA Technical Reports Server (NTRS)

The present investigation is concerned with a sensitivity analysis of the Decelerated Steep Approach and Landing (DSAL) maneuver to on-board and ground-based navigation system parameters. The Instrument Meteorological Conditions (IMC) DSAL maneuver involves decelerating to zero range rate while tracking the localizer and glideslope. The considered study investigated the performance of the navigation systems using Constant Deceleration Profile (CDP) guidance and a six degrees glideslope trajectory. A closed-loop computer simulation of the UH1H helicopter DSAL system was developed for the sensitivity analysis. Conclusions on system performance parameter sensitivity are discussed.

Karmali, M. S.; Phatak, A. V.; Bull, J. S.; Peach, L. L.; Demko, P. S.

1984-01-01

30

Guidance and Control Algorithms for the Mars Entry, Descent and Landing Systems Analysis  

NASA Technical Reports Server (NTRS)

The purpose of the Mars Entry, Descent and Landing Systems Analysis (EDL-SA) study was to identify feasible technologies that will enable human exploration of Mars, specifically to deliver large payloads to the Martian surface. This paper focuses on the methods used to guide and control two of the contending technologies, a mid- lift-to-drag (L/D) rigid aeroshell and a hypersonic inflatable aerodynamic decelerator (HIAD), through the entry portion of the trajectory. The Program to Optimize Simulated Trajectories II (POST2) is used to simulate and analyze the trajectories of the contending technologies and guidance and control algorithms. Three guidance algorithms are discussed in this paper: EDL theoretical guidance, Numerical Predictor-Corrector (NPC) guidance and Analytical Predictor-Corrector (APC) guidance. EDL-SA also considered two forms of control: bank angle control, similar to that used by Apollo and the Space Shuttle, and a center-of-gravity (CG) offset control. This paper presents the performance comparison of these guidance algorithms and summarizes the results as they impact the technology recommendations for future study.

Davis, Jody L.; CwyerCianciolo, Alicia M.; Powell, Richard W.; Shidner, Jeremy D.; Garcia-Llama, Eduardo

2010-01-01

31

Land Cover Change Community-based Processing and Analysis System (LC-ComPS): Lessons Learned from Technology Infusion  

NASA Astrophysics Data System (ADS)

The Land Cover Change Community-based Processing and Analysis System (LC-ComPS) combines grid technology, existing science modules, and dynamic workflows to enable users to complete advanced land data processing on data available from local and distributed archives. Changes in land cover represent a direct link between human activities and the global environment, and in turn affect Earth's climate. Thus characterizing land cover change has become a major goal for Earth observation science. Many science algorithms exist to generate new products (e.g., surface reflectance, change detection) used to study land cover change. The overall objective of the LC-ComPS is to release a set of tools and services to the land science community that can be implemented as a flexible LC-ComPS to produce surface reflectance and land-cover change information with ground resolution on the order of Landsat-class instruments. This package includes software modules for pre-processing Landsat-type satellite imagery (calibration, atmospheric correction, orthorectification, precision registration, BRDF correction) for performing land-cover change analysis and includes pre-built workflow chains to automatically generate surface reflectance and land-cover change products based on user input. In order to meet the project objectives, the team created the infrastructure (i.e., client-server system with graphical and machine interfaces) to expand the use of these existing science algorithm capabilities in a community with distributed, large data archives and processing centers. Because of the distributed nature of the user community, grid technology was chosen to unite the dispersed community resources. At that time, grid computing was not used consistently and operationally within the Earth science research community. Therefore, there was a learning curve to configure and implement the underlying public key infrastructure (PKI) interfaces, required for the user authentication, secure file transfer and remote job execution on the grid network of machines. In addition, science support was needed to vet that the grid technology did not have any adverse affects of the science module outputs. Other open source, unproven technologies, such as a workflow package to manage jobs submitted by the user, were infused into the overall system with successful results. This presentation will discuss the basic capabilities of LC-ComPS, explain how the technology was infused, and provide lessons learned for using and integrating the various technologies while developing and operating the system, and finally outline plans moving forward (maintenance and operations decisions) based on the experience to date.

Masek, J.; Rao, A.; Gao, F.; Davis, P.; Jackson, G.; Huang, C.; Weinstein, B.

2008-12-01

32

Variational sensitivity analysis and data assimilation studies of the coupled land surface-atmospheric boundary layer system  

E-print Network

One of the fundamental components of Earth system science is understanding coupled land-atmosphere processes. The land plays an especially important role in the climate system principally via the regulation of surface ...

Margulis, Steven A. (Steven Adam), 1973-

2002-01-01

33

Life cycle inventory-based analysis of greenhouse gas emissions from arable land farming systems in Hokkaido, northern Japan  

Microsoft Academic Search

To assess their impacts on net global warming, total greenhouse gas emissions (mainly CO2, N2O and CH4) from agricultural production in arable land cropping systems in the Tokachi region of Hokkaido, Japan, were estimated using life cycle inventory (LCI) analysis. The LCI data included CO2 emissions from on-farm and off-farm fossil fuel consumption, soil CO2 emissions induced by the decomposition

Nobuhisa Koga; Takuji Sawamoto; Haruo Tsuruta

2006-01-01

34

Analysis and design of a capsule landing system and surface vehicle control system for Mars exploration  

NASA Technical Reports Server (NTRS)

The following tasks related to the design, construction, and evaluation of a mobile planetary vehicle for unmanned exploration of Mars are discussed: (1) design and construction of a 0.5 scale dynamic vehicle; (2) mathematical modeling of vehicle dynamics; (3) experimental 0.4 scale vehicle dynamics measurements and interpretation; (4) vehicle electro-mechanical control systems; (5) remote control systems; (6) collapsibility and deployment concepts and hardware; (7) design, construction and evaluation of a wheel with increased lateral stiffness, (8) system design optimization; (9) design of an on-board computer; (10) design and construction of a laser range finder; (11) measurement of reflectivity of terrain surfaces; (12) obstacle perception by edge detection; (13) terrain modeling based on gradients; (14) laser scan systems; (15) path selection system simulation and evaluation; (16) gas chromatograph system concepts; (17) experimental chromatograph separation measurements and chromatograph model improvement and evaluation.

Frederick, D. K.; Lashmet, P. K.; Moyer, W. R.; Sandor, G. N.; Shen, C. N.; Smith, E. J.; Yerazunis, S. W.

1973-01-01

35

Analysis and design of a capsule landing system and surface vehicle control system for Mars exploration  

NASA Technical Reports Server (NTRS)

Problems related to an unmanned exploration of the planet Mars by means of an autonomous roving planetary vehicle are investigated. These problems include: design, construction and evaluation of the vehicle itself and its control and operating systems. More specifically, vehicle configuration, dynamics, control, propulsion, hazard detection systems, terrain sensing and modelling, obstacle detection concepts, path selection, decision-making systems, and chemical analyses of samples are studied. Emphasis is placed on development of a vehicle capable of gathering specimens and data for an Augmented Viking Mission or to provide the basis for a Sample Return Mission.

Gisser, D. G.; Frederick, D. K.; Lashmet, P. K.; Sandor, G. N.; Shen, C. N.; Yerazunis, S. Y.

1975-01-01

36

Microwave Landing System Area Navigation  

Microsoft Academic Search

The International Civil Aviation Organization (ICAO) Standards and Recommended Practices (SARPS) states that the Time Reference Scanning Beam (TRSB) Microwave Landing System will supplant the existing Instrument Landing System (ILS) as the recognized international standard as early as 1995. The MLS provides the ability to determine the aircraft's position in three dimensional space over a large coverage volume in the

James Remer; Barry Billmann

1987-01-01

37

Analysis of Multiple Precipitation Products and Preliminary Assessment of Their Impact on Global Land Data Assimilation System (GLDAS) Land Surface States  

NASA Technical Reports Server (NTRS)

Land surface models (LSMs) are computer programs, similar to weather and climate prediction models, which simulate the stocks and fluxes of water (including soil moisture, snow, evaporation, and runoff) and energy (including the temperature of and sensible heat released from the soil) after they arrive on the land surface as precipitation and sunlight. It is not currently possible to measure all of the variables of interest everywhere on Earth with sufficient accuracy and space-time resolution. Hence LSMs have been developed to integrate the available observations with our understanding of the physical processes involved, using powerful computers, in order to map these stocks and fluxes as they change in time. The maps are used to improve weather forecasts, support water resources and agricultural applications, and study the Earth's water cycle and climate variability. NASA's Global Land Data Assimilation System (GLDAS) project facilitates testing of several different LSMs with a variety of input datasets (e.g., precipitation, plant type). Precipitation is arguably the most important input to LSMs. Many precipitation datasets have been produced using satellite and rain gauge observations and weather forecast models. In this study, seven different global precipitation datasets were evaluated over the United States, where dense rain gauge networks contribute to reliable precipitation maps. We then used the seven datasets as inputs to GLDAS simulations, so that we could diagnose their impacts on output stocks and fluxes of water. In terms of totals, the Climate Prediction Center (CPC) Merged Analysis of Precipitation (CMAP) had the closest agreement with the US rain gauge dataset for all seasons except winter. The CMAP precipitation was also the most closely correlated in time with the rain gauge data during spring, fall, and winter, while the satellitebased estimates performed best in summer. The GLDAS simulations revealed that modeled soil moisture is highly sensitive to precipitation, with differences in spring and summer as large as 45% depending on the choice of precipitation input.

Gottschalck, Jon; Meng, Jesse; Rodel, Matt; Houser, paul

2005-01-01

38

Sensitivity analysis of land unit suitability for conservation using a knowledge-based system.  

PubMed

The availability of spatially continuous data layers can have a strong impact on selection of land units for conservation purposes. The suitability of ecological conditions for sustaining the targets of conservation is an important consideration in evaluating candidate conservation sites. We constructed two fuzzy logic-based knowledge bases to determine the conservation suitability of land units in the interior Columbia River basin using NetWeaver software in the Ecosystem Management Decision Support application framework. Our objective was to assess the sensitivity of suitability ratings, derived from evaluating the knowledge bases, to fuzzy logic function parameters and to the removal of data layers (land use condition, road density, disturbance regime change index, vegetation change index, land unit size, cover type size, and cover type change index). The amount and geographic distribution of suitable land polygons was most strongly altered by the removal of land use condition, road density, and land polygon size. Removal of land use condition changed suitability primarily on private or intensively-used public land. Removal of either road density or land polygon size most strongly affected suitability on higher-elevation US Forest Service land containing small-area biophysical environments. Data layers with the greatest influence differed in rank between the two knowledge bases. Our results reinforce the importance of including both biophysical and socio-economic attributes to determine the suitability of land units for conservation. The sensitivity tests provided information about knowledge base structuring and parameterization as well as prioritization for future data needs. PMID:20623353

Humphries, Hope C; Bourgeron, Patrick S; Reynolds, Keith M

2010-08-01

39

Sensitivity Analysis of Land Unit Suitability for Conservation Using a Knowledge-Based System  

NASA Astrophysics Data System (ADS)

The availability of spatially continuous data layers can have a strong impact on selection of land units for conservation purposes. The suitability of ecological conditions for sustaining the targets of conservation is an important consideration in evaluating candidate conservation sites. We constructed two fuzzy logic-based knowledge bases to determine the conservation suitability of land units in the interior Columbia River basin using NetWeaver software in the Ecosystem Management Decision Support application framework. Our objective was to assess the sensitivity of suitability ratings, derived from evaluating the knowledge bases, to fuzzy logic function parameters and to the removal of data layers (land use condition, road density, disturbance regime change index, vegetation change index, land unit size, cover type size, and cover type change index). The amount and geographic distribution of suitable land polygons was most strongly altered by the removal of land use condition, road density, and land polygon size. Removal of land use condition changed suitability primarily on private or intensively-used public land. Removal of either road density or land polygon size most strongly affected suitability on higher-elevation US Forest Service land containing small-area biophysical environments. Data layers with the greatest influence differed in rank between the two knowledge bases. Our results reinforce the importance of including both biophysical and socio-economic attributes to determine the suitability of land units for conservation. The sensitivity tests provided information about knowledge base structuring and parameterization as well as prioritization for future data needs.

Humphries, Hope C.; Bourgeron, Patrick S.; Reynolds, Keith M.

2010-08-01

40

Skin Temperature Analysis and Bias Correction in a Coupled Land-Atmosphere Data Assimilation System  

NASA Technical Reports Server (NTRS)

In an initial investigation, remotely sensed surface temperature is assimilated into a coupled atmosphere/land global data assimilation system, with explicit accounting for biases in the model state. In this scheme, an incremental bias correction term is introduced in the model's surface energy budget. In its simplest form, the algorithm estimates and corrects a constant time mean bias for each gridpoint; additional benefits are attained with a refined version of the algorithm which allows for a correction of the mean diurnal cycle. The method is validated against the assimilated observations, as well as independent near-surface air temperature observations. In many regions, not accounting for the diurnal cycle of bias caused degradation of the diurnal amplitude of background model air temperature. Energy fluxes collected through the Coordinated Enhanced Observing Period (CEOP) are used to more closely inspect the surface energy budget. In general, sensible heat flux is improved with the surface temperature assimilation, and two stations show a reduction of bias by as much as 30 Wm(sup -2) Rondonia station in Amazonia, the Bowen ratio changes direction in an improvement related to the temperature assimilation. However, at many stations the monthly latent heat flux bias is slightly increased. These results show the impact of univariate assimilation of surface temperature observations on the surface energy budget, and suggest the need for multivariate land data assimilation. The results also show the need for independent validation data, especially flux stations in varied climate regimes.

Bosilovich, Michael G.; Radakovich, Jon D.; daSilva, Arlindo; Todling, Ricardo; Verter, Frances

2006-01-01

41

A study of instrument landing system on decimeter-wave  

Microsoft Academic Search

This paper puts forward a new type of landing system based on decimeter wave, in-depth analysis on the forming of navigation information under this system, indicates the characteristics of the landing system, and defines the main technologies; provides the approach to realize the landing system with the application of decimeter wave instruments, puts forward the methods and the simulation of

Lijian Shi; Yongsheng Wang; Dewei Wu; Xiubin Zhao

2007-01-01

42

Revised Land Use Characteristic Dataset for Asia and Southwest Asia for the Navy Aerosol Analysis and Prediction System (NAAPS)  

NASA Astrophysics Data System (ADS)

Presently, the Navy Aerosol Analysis and Prediction System (NAAPS) uses the U.S. Geological Survey (USGS) land use characteristic dataset to determine global dust emission areas. The USGS dataset was developed from Advanced Very High-Resolution Radiometer 1-km data from April 1992 to March 1993. In the past decade drastic changes in land and water use in Asia and Southwest Asia have quickly outdated this dataset. In China and Mongolia, age-old practices of farming and animal husbandry have been abandoned. Herders have too many animals in one location allowing the grassland to be eaten away and leaving vast areas of topsoil exposed and primed for removal by the wind. In the case of Southwest Asia, a four-year drought is in progress. Many of the wetlands and marshes in the river deltas are drying up from the lack of water runoff. To compound the problem several new dams were and are being built along the major watersheds. In particular, Iraq's dam building in the 1990's and politically driven draining of the Mesopotamian marshes between the Tigris and Euphrates rivers has lead to the near disappearance of this historical marshland. To incorporate these changes we are updating the USGS land use characteristic dataset using GIS-like software named ENVI (Environment for Visualizing Images), 1 km National Geophysical Data Center (NGDC) global topographical data, satellite imagery, and recently released governmental maps and reports. (For example, within the last two years the Chinese and Mongolian governments have released land degradation and desertification maps to satisfy the requirements set forth by United Nations Convention to Combat Desertification.) The steps taken to create the new land use characteristic database will be described in detail. Before (non-dust producing areas) and after (dust producing areas) examples will be shown.

Walker, A. L.; Richardson, K.; Westphal, D. L.

2002-12-01

43

Status of Instrument Landing Systems  

Microsoft Academic Search

During the past ten years a large number of instrument landing systems have undergone development and tests and a considerable fund of information has been accumulated concerning the shortcomings and advantages of each. The major airlines of the United States, the Federal Communications Commission, the Bureau of Air Commerce, and the Subcommittee on Instrument Landing Devices of the Radio Technical

W. E. Jackson

1938-01-01

44

Advanced Land Imager Assessment System  

NASA Technical Reports Server (NTRS)

The Advanced Land Imager Assessment System (ALIAS) supports radiometric and geometric image processing for the Advanced Land Imager (ALI) instrument onboard NASA s Earth Observing-1 (EO-1) satellite. ALIAS consists of two processing subsystems for radiometric and geometric processing of the ALI s multispectral imagery. The radiometric processing subsystem characterizes and corrects, where possible, radiometric qualities including: coherent, impulse; and random noise; signal-to-noise ratios (SNRs); detector operability; gain; bias; saturation levels; striping and banding; and the stability of detector performance. The geometric processing subsystem and analysis capabilities support sensor alignment calibrations, sensor chip assembly (SCA)-to-SCA alignments and band-to-band alignment; and perform geodetic accuracy assessments, modulation transfer function (MTF) characterizations, and image-to-image characterizations. ALIAS also characterizes and corrects band-toband registration, and performs systematic precision and terrain correction of ALI images. This system can geometrically correct, and automatically mosaic, the SCA image strips into a seamless, map-projected image. This system provides a large database, which enables bulk trending for all ALI image data and significant instrument telemetry. Bulk trending consists of two functions: Housekeeping Processing and Bulk Radiometric Processing. The Housekeeping function pulls telemetry and temperature information from the instrument housekeeping files and writes this information to a database for trending. The Bulk Radiometric Processing function writes statistical information from the dark data acquired before and after the Earth imagery and the lamp data to the database for trending. This allows for multi-scene statistical analyses.

Chander, Gyanesh; Choate, Mike; Christopherson, Jon; Hollaren, Doug; Morfitt, Ron; Nelson, Jim; Nelson, Shar; Storey, James; Helder, Dennis; Ruggles, Tim; Kaita, Ed; Levy, Raviv; Ong, Lawrence; Markham, Brian; Schweiss, Robert

2008-01-01

45

A design for a new catalog manager and associated file management for the Land Analysis System (LAS)  

NASA Technical Reports Server (NTRS)

Due to the larger number of different types of files used in an image processing system, a mechanism for file management beyond the bounds of typical operating systems is necessary. The Transportable Applications Executive (TAE) Catalog Manager was written to meet this need. Land Analysis System (LAS) users at the EROS Data Center (EDC) encountered some problems in using the TAE catalog manager, including catalog corruption, networking difficulties, and lack of a reliable tape storage and retrieval capability. These problems, coupled with the complexity of the TAE catalog manager, led to the decision to design a new file management system for LAS, tailored to the needs of the EDC user community. This design effort, which addressed catalog management, label services, associated data management, and enhancements to LAS applications, is described. The new file management design will provide many benefits including improved system integration, increased flexibility, enhanced reliability, enhanced portability, improved performance, and improved maintainability.

Greenhagen, Cheryl

1986-01-01

46

Global Land Information System (GLIS)  

USGS Publications Warehouse

The Global Land Information System (GLIS) is an interactive computer system developed by the U.S. Geological Survey (USGS) for scientists seeking sources of information about the Earth's land surfaces. GLIS contains "metadata," that is, descriptive information about data sets. Through GLIS, scientists can evaluate data sets, determine their availability, and place online requests for products. GLIS is more, however, than a mere list of products. It offers online samples of earth science data that may be ordered through the system.

U.S. Geological Survey

1992-01-01

47

Sensitivity Analysis of Land Unit Suitability for Conservation Using a Knowledge-Based System  

Microsoft Academic Search

The availability of spatially continuous data layers can have a strong impact on selection of land units for conservation purposes. The suitability of ecological conditions for sustaining the targets of conservation is an important consideration in evaluating candidate conservation sites. We constructed two fuzzy logic-based knowledge bases to determine the conservation suitability of land units in the interior Columbia River

Hope C. Humphries; Patrick S. Bourgeron; Keith M. Reynolds

2010-01-01

48

Dual Heat Pulse, Dual Layer Thermal Protection System Sizing Analysis and Trade Studies for Human Mars Entry Descent and Landing  

NASA Technical Reports Server (NTRS)

NASA has been recently updating design reference missions for the human exploration of Mars and evaluating the technology investments required to do so. The first of these started in January 2007 and developed the Mars Design Reference Architecture 5.0 (DRA5). As part of DRA5, Thermal Protection System (TPS) sizing analysis was performed on a mid L/D rigid aeroshell undergoing a dual heat pulse (aerocapture and atmospheric entry) trajectory. The DRA5 TPS subteam determined that using traditional monolithic ablator systems would be mass expensive. They proposed a new dual-layer TPS concept utilizing an ablator atop a low thermal conductivity insulative substrate to address the issue. Using existing thermal response models for an ablator and insulative tile, preliminary hand analysis of the dual layer concept at a few key heating points indicated that the concept showed potential to reduce TPS masses and warranted further study. In FY09, the followon Entry, Descent and Landing Systems Analysis (EDL-SA) project continued by focusing on Exploration-class cargo or crewed missions requiring 10 to 50 metric tons of landed payload. The TPS subteam advanced the preliminary dual-layer TPS analysis by developing a new process and updated TPS sizing code to rapidly evaluate mass-optimized, full body sizing for a dual layer TPS that is capable of dual heat pulse performance. This paper describes the process and presents the results of the EDL-SA FY09 dual-layer TPS analyses on the rigid mid L/D aeroshell. Additionally, several trade studies were conducted with the sizing code to evaluate the impact of various design factors, assumptions and margins.

McGuire, Mary Kathleen

2011-01-01

49

Sensitivity Analysis of Land Unit Suitability for Conservation Using a Knowledge-Based System  

Microsoft Academic Search

The availability of spatially continuous data layers can have a strong impact on selection of land units for conservation\\u000a purposes. The suitability of ecological conditions for sustaining the targets of conservation is an important consideration\\u000a in evaluating candidate conservation sites. We constructed two fuzzy logic-based knowledge bases to determine the conservation\\u000a suitability of land units in the interior Columbia River

Hope C. HumphriesPatrick; Patrick S. Bourgeron; Keith M. Reynolds

2010-01-01

50

The Land Gini Coefficient and Its Application for Land Use Structure Analysis in China  

PubMed Central

We introduce the Gini coefficient to assess the rationality of land use structure. The rapid transformation of land use in China provides a typical case for land use structure analysis. In this study, a land Gini coefficient (LGC) analysis tool was developed. The land use structure rationality was analyzed and evaluated based on statistical data for China between 1996 and 2008. The results show: (1)The LGC of three major land use types–farmland, built-up land and unused land–was smaller when the four economic districts were considered as assessment units instead of the provinces. Therefore, the LGC is spatially dependent; if the calculation unit expands, then the LGC decreases, and this relationship does not change with time. Additionally, land use activities in different provinces of a single district differed greatly. (2) At the national level, the LGC of the three main land use types indicated that during the 13 years analyzed, the farmland and unused land were evenly distributed across China. However, the built-up land distribution was relatively or absolutely unequal and highlights the rapid urbanization in China. (3) Trends in the distribution of the three major land use types are very different. At the national level, when using a district as the calculation unit, the LGC of the three main land use types increased, and their distribution became increasingly concentrated. However, when a province was used as the calculation unit, the LGC of the farmland increased, while the LGC of the built-up and unused land decreased. These findings indicate that the distribution of the farmland became increasingly concentrated, while the built-up land and unused land became increasingly uniform. (4) The LGC analysis method of land use structure based on geographic information systems (GIS) is flexible and convenient. PMID:24130764

Zheng, Xinqi; Xia, Tian; Yang, Xin; Yuan, Tao; Hu, Yecui

2013-01-01

51

Integrating NASA's Land Analysis System (LAS) image processing software with an appropriate Geographic Information System (GIS): A review of candidates in the public domain  

NASA Technical Reports Server (NTRS)

A user requirements analysis (URA) was undertaken to determine and appropriate public domain Geographic Information System (GIS) software package for potential integration with NASA's LAS (Land Analysis System) 5.0 image processing system. The necessity for a public domain system was underscored due to the perceived need for source code access and flexibility in tailoring the GIS system to the needs of a heterogenous group of end-users, and to specific constraints imposed by LAS and its user interface, Transportable Applications Executive (TAE). Subsequently, a review was conducted of a variety of public domain GIS candidates, including GRASS 3.0, MOSS, IEMIS, and two university-based packages, IDRISI and KBGIS. The review method was a modified version of the GIS evaluation process, development by the Federal Interagency Coordinating Committee on Digital Cartography. One IEMIS-derivative product, the ALBE (AirLand Battlefield Environment) GIS, emerged as the most promising candidate for integration with LAS. IEMIS (Integrated Emergency Management Information System) was developed by the Federal Emergency Management Agency (FEMA). ALBE GIS is currently under development at the Pacific Northwest Laboratory under contract with the U.S. Army Corps of Engineers' Engineering Topographic Laboratory (ETL). Accordingly, recommendations are offered with respect to a potential LAS/ALBE GIS linkage and with respect to further system enhancements, including coordination with the development of the Spatial Analysis and Modeling System (SAMS) GIS in Goddard's IDM (Intelligent Data Management) developments in Goddard's National Space Science Data Center.

Rochon, Gilbert L.

1989-01-01

52

Survey and Analysis of Land Satellite Remote Sensing Applied in Highway Transportations Infrastructure and System Engineering  

Microsoft Academic Search

The US Department of Transportation (US DOT) initiated the Commercial Remote Sensing and Spatial Information Technology Application to Transportation program in 1999 in collaboration with the National Aeronautics and Space Administration (NASA). With the efforts in the past several years, tremendous accomplishments have been made. This paper makes a survey for the applications of land observation satellite remote sensing in

Guoqing Zhou; Daiyong Wei

2008-01-01

53

Information analysis of a spatial database for ecological land classification  

NASA Technical Reports Server (NTRS)

An ecological land classification was developed for a complex region in southern California using geographic information system techniques of map overlay and contingency table analysis. Land classes were identified by mutual information analysis of vegetation pattern in relation to other mapped environmental variables. The analysis was weakened by map errors, especially errors in the digital elevation data. Nevertheless, the resulting land classification was ecologically reasonable and performed well when tested with higher quality data from the region.

Davis, Frank W.; Dozier, Jeff

1990-01-01

54

LAND USE, COVER AND FORMS CLASSIFICATION SYSTEM  

E-print Network

FLORIDA LAND USE, COVER AND FORMS CLASSIFICATION SYSTEM HANDBOOK JANUARY 1999 DEPARTMENT OF TRANSPORTATION SURVEYING AND MAPPING GEOGRAPHIC MAPPING SECTION #12;FLORIDA LAND USE, COVER AND FORMS LAND USE, COVER AND FORMS CLASSIFICATION SYSTEM ABOUT THIS EDITION: This is an updated FLORIDA LAND USE

Binford, Michael W.

55

The Global Land Data Assimilation System  

Microsoft Academic Search

A Global Land Data Assimilation System (GLDAS) has been developed. Its purpose is to ingest satellite- and ground-based observational data products, using advanced land surface modeling and data assimilation techniques, in order to generate optimal fields of land surface states and fluxes. GLDAS is unique in that it is an uncoupled land surface modeling system that drives multiple models, integrates

M. Rodell; U. Jambor; J. Gottschalck; K. Mitchell; C.-J. Meng; K. Arsenault; B. Cosgrove; J. Radakovich; M. Bosilovich; J. K. Entin; J. P. Walker; D. Lohmann; D. Toll

2004-01-01

56

Instrument Landing System Performance Prediction  

Microsoft Academic Search

An electromagnetic scattering model has been developed for predicting Instrument Landing System (ILS) localizer and glide slope performance. The model is used to predict course structure degradation resulting from a change in the airport environment. Such changes include the addition of new hangars, terminal buildings and control towers as well as terrain modifications. In addition, the model is used to

G. Chin; L. Jordan; D. Kahn; S. Morin

1975-01-01

57

Landing gear energy absorption system  

NASA Technical Reports Server (NTRS)

A landing pad system is described for absorbing horizontal and vertical impact forces upon engagement with a landing surface where circumferentially arranged landing struts respectively have a clevis which receives a slidable rod member and where the upper portion of a slidable rod member is coupled to the clevis by friction washers which are force fit onto the rod member to provide for controlled constant force energy absorption when the rod member moves relative to the clevis. The lower end of the friction rod is pivotally attached by a ball and socket to a support plate where the support plate is arranged to slide in a transverse direction relative to a housing which contains an energy absorption material for absorbing energy in a transverse direction.

Hansen, Christopher P. (inventor)

1994-01-01

58

An Automated Land Analysis System (ALAS) for applications at a range of spatial scales: Watershed to global  

SciTech Connect

Recent advances in Digital Elevation Model (DEM) data availability and topographic analysis have enabled us to develop an Automated Land Analysis System (ALAS). ALAS is based on a series of codes which determine topographic and hydrologic characteristics at each pixel, watershed, and each large scale cell. The input requirements are a DEM from any location in the world, it`s resolution, and array size. A Motif accessed script reads in these inputs and generates a series of data sets which further describe the watershed properties such as flow directions, hydrologic characteristic probability density functions, etc.). Postscript files and arrays indicating the fme river networks and each subcatchment, as well as numerous other properties, are produced and catalogued. The motivation behind the development of ALAS is a direct response to the conceptualization of convergent scales between hydrologic and atmospheric models as defined by the World Climate Research Programme. The remainder of this paper highlights ALAS components, capabilities, and provides some discussion on its applications.

Miller, N.L.

1995-08-01

59

Application and analysis of anchored geosynthetic systems for stabilization of abandoned mine land slopes  

SciTech Connect

An anchored geosynthetic system (AGS) was used in the remediation of a landslide associated with an abandoned coal mine located near Hindman, Kentucky. In concept, AGS is a system that provides in-situ stabilization of soil slopes by combining a surface-deployed geosynthetic with an anchoring system of driven reinforcing rods similar to soil nailing. Installation of the system of driven reinforcing rods similar to soil nailing. Installation of the system involves tensioning a geosynthetic over a slope`s surface by driving anchors through the geosynthetic at a given spacing and distance. By tensioning the geosynthetic over the slope`s surface, a compressive load is applied to the slope. Benefits of AGS are described to include the following: (1) increase soil strength due to soil compression including increased compressive loading on potential failure surfaces, (2) soil reinforcement through soil nailing, (3), halt of soil creep, (4) erosion control, and (5) long term soil consolidation. Following installation of the AGS and one year of monitoring, it was found that the anchored geosynthetic system only provided some of the reported benefits and in general did not function as an active stabilization system. This was due in part to the inability of the system to provide and maintain loading on the geosynthetic. The geosynthetic, however, did tension when slope movement occurred and prevented the slope from failing. Thus, the system functioned more as a passive restraint system and appeared to function well over the monitoring period.

Vitton, S.J. [Michigan Technological Univ., Houghton, MI (United States); Whitman, F. [Testing Inc., Decatur, AL (United States); Liang, R.Y. [Univ. of Akron, OH (United States); Harris, W.W.

1996-12-31

60

Land mobile satellite demonstration system  

NASA Technical Reports Server (NTRS)

A land mobile satellite demonstration system is described. It ulilizes the INMARSAT MARECS B2 satellite at 26 degrees W. The system provides data transmission using a poll-response protocol with error detection and retransmission at 200 b/s rate. For most tests a 1.8 inch monopole antenna was used, along with a satellite EIRP normally used for four voice channels. A brief summary of the results are given and the overall system consisting of three elements in addition to the satellite (the mobile unit, the base station, and the office terminal and map display) is described. Throughput statistics from one trip are summarized.

Gooch, Guy M.; Nicholas, David C.

1988-01-01

61

Land Information Systems in Developing Countries  

E-print Network

Land Information Systems in Developing Countries: Bibliography Compiled by: Harlan Onsrud Jeff Acknowledgments Articles on land information systems and cadastral systems in developing countries are spread and Geomatics Engineering at the University of New Brunswick and the Land Tenure Center at the University

California at Santa Barbara, University of

62

Guidance characteristics of GNSS landing systems  

Microsoft Academic Search

Technical and operation concepts for precision landing have evolved around the signal in space characteristics of the Instrument Landing System (ILS). For the Global Navigation Satellite System (GNSS) Landing System (GLS), many of these characteristics will be dependent on computational processes inside the airborne receiver. Development of GLS standards creates an opportunity to improve on inherent ILS limitations while retaining

A. Stratton

1998-01-01

63

Testing and analysis of dual-mode adaptive landing gear, taxi mode test system for YF-12A  

NASA Technical Reports Server (NTRS)

The effectiveness of a dual mode adaptive landing gear system in reducing the dynamic response of an airplane during ground taxiing was studied. The dynamic taxi tests of the YF-12A research airplane are presented. A digital computer program which simulated the test conditions is discussed. The dual mode system as tested provides dynamic taxi response reductions of 25 percent at the cg and 30 to 45 percent at the cockpit.

Gamon, M. A.

1979-01-01

64

UNIVERSITY-NATIONAL OCEANOGRAPHIC LABORATORY SYSTEM Moss Landing Marine Laboratories 8272 Moss Landing Road, Moss Landing, CA 95039  

E-print Network

UNIVERSITY-NATIONAL OCEANOGRAPHIC LABORATORY SYSTEM Moss Landing Marine Laboratories 8272 Moss Landing Road, Moss Landing, CA 95039 (831)-771-4410 Fax (831) 632-4413 www.unols.org office SYSTEM Moss Landing Marine Laboratories 8272 Moss Landing Road, Moss Landing, CA 95039 (831)-771-4410 Fax

65

Analysis of Landing-Gear Behavior  

NASA Technical Reports Server (NTRS)

This report presents a theoretical study of the behavior of the conventional type of oleo-pneumatic landing gear during the process of landing impact. The basic analysis is presented in a general form and treats the motions of the landing gear prior to and subsequent to the beginning of shock-strut deflection. The applicability of the analysis to actual landing gears has been investigated for the particular case of a vertical landing gear in the absence of drag loads by comparing calculated results with experimental drop-test data for impacts with and without tire bottoming. The calculated behavior of the landing gear was found to be in good agreement with the drop-test data.

Milwitzky, Benjamin; Cook, Francis E

1953-01-01

66

Crew Office Evaluation of a Precision Lunar Landing System  

NASA Technical Reports Server (NTRS)

A representative Human System Interface for a precision lunar landing system, ALHAT, has been developed as a platform for prototype visualization and interaction concepts. This facilitates analysis of crew interaction with advanced sensors and AGNC systems. Human-in-the-loop evaluations with representatives from the Crew Office (i.e. astronauts) and Mission Operations Directorate (MOD) were performed to refine the crew role and information requirements during the final phases of landing. The results include a number of lessons learned from Shuttle that are applicable to the design of a human supervisory landing system and cockpit. Overall, the results provide a first order analysis of the tasks the crew will perform during lunar landing, an architecture for the Human System Interface based on these tasks, as well as details on the information needs to land safely.

Major, Laura M.; Duda, Kevin R.; Hirsh, Robert L.

2011-01-01

67

Flight inspection of instrument landing system  

Microsoft Academic Search

?This paper aims to familiarize experts from other fields with issues of flight inspection of instrument landing system (ILS) and its assessment contained in the elaborated documentation. At first in chapter I. the standard volumes of the instrument landing system are described, followed by standard profiles flown during the flight inspection in chapter II. Finally, chapter III. describes the instrument

Andrej Novak; Jan Pitor

2011-01-01

68

Application of tire dynamics to aircraft landing gear design analysis  

NASA Technical Reports Server (NTRS)

The tire plays a key part in many analyses used for design of aircraft landing gear. Examples include structural design of wheels, landing gear shimmy, brake whirl, chatter and squeal, complex combination of chatter and shimmy on main landing gear (MLG) systems, anti-skid performance, gear walk, and rough terrain loads and performance. Tire parameters needed in the various analyses are discussed. Two tire models are discussed for shimmy analysis, the modified Moreland approach and the von Schlippe-Dietrich approach. It is shown that the Moreland model can be derived from the Von Schlippe-Dietrich model by certain approximations. The remaining analysis areas are discussed in general terms and the tire parameters needed for each are identified. Accurate tire data allows more accurate design analysis and the correct prediction of dynamic performance of aircraft landing gear.

Black, R. J.

1983-01-01

69

ForEnvironmentalManagementofMilitaryLands Land Condition-Trend Analysis  

E-print Network

THECENTER ForEnvironmentalManagementofMilitaryLands Land Condition-Trend Analysis (LCTA) II Survey Using MS Access to Analyze Land Condition-Trend Analysis Data A Beginner's Guide By Christine Bern CENTER FOR ENVIRONMENTAL MANAGEMENT OF MILITARY LANDS Colorado State University Fort Collins, Colorado

70

Reorienting land degradation towards sustainable land management: Linking sustainable livelihoods with ecosystem services in rangeland systems.  

PubMed

This paper identifies new ways of moving from land degradation towards sustainable land management through the development of economic mechanisms. It identifies new mechanisms to tackle land degradation based on retaining critical levels of natural capital whilst basing livelihoods on a wider range of ecosystem services. This is achieved through a case study analysis of the Kalahari rangelands in southwest Botswana. The paper first describes the socio-economic and ecological characteristics of the Kalahari rangelands and the types of land degradation taking place. It then focuses on bush encroachment as a way of exploring new economic instruments (e.g. Payments for Ecosystem Services) designed to enhance the flow of ecosystem services that support livelihoods in rangeland systems. It does this by evaluating the likely impacts of bush encroachment, one of the key forms of rangeland degradation, on a range of ecosystem services in three land tenure types (private fenced ranches, communal grazing areas and Wildlife Management Areas), before considering options for more sustainable land management in these systems. We argue that with adequate policy support, economic mechanisms could help reorient degraded rangelands towards more sustainable land management. PMID:25617787

Reed, M S; Stringer, L C; Dougill, A J; Perkins, J S; Atlhopheng, J R; Mulale, K; Favretto, N

2015-03-15

71

A visual navigation system for autonomous land vehicles  

Microsoft Academic Search

A modular system architecture has been developed to support visual navigation by an autonomous land vehicle. The system consists of vision modules performing image processing, three-dimensional shape recovery, and geometric reasoning, as well as modules for planning, navigating, and piloting. The system runs in two distinct modes, bootstrap and feedforward. The bootstrap mode requires analysis of entire images to find

ALLEN M. WAXMAN; JACQUELINE J. LEMOIGNE; LARRY S. DAVIS; BABU SRINIVASAN; TODD R. KUSHNER; Eli Liang; THARAKESH SIDDALINGAIAH

1987-01-01

72

International Symposium on Urban Land Policies and Land Use Systems Center for Urban Studies  

E-print Network

1 International Symposium on Urban Land Policies and Land Use Systems Center for Urban Studies original land-use tools, such as the Legal Density Ceiling, a kind of land tax that the Brazilian. Furthermore, the strong land-use control policy enforced after the second World War in France has enabled

Paris-Sud XI, Université de

73

Autonomous landing guidance system validation  

Microsoft Academic Search

ALG is a combination of raster imaging sensor, head-up displays, flight guidance and procedures which allow pilots to perform hand flown aircraft maneuvers in adverse weather, at night, or in low visibility conditions at facilities with minimal or no ground aids. Maneuvers in the context of ALG relate to takeoff, landing, rollout, taxi and terminal parking. Commercial needs are driven

Long Q. Bui; Michael R. Franklin; Christopher Taylor; Graham Neilson

1997-01-01

74

An analysis of Milwaukee county land use  

NASA Technical Reports Server (NTRS)

The identification and classification of urban and suburban phenomena through analysis of remotely-acquired sensor data can provide information of great potential value to many regional analysts. Such classifications, particularly those using spectral data obtained from satellites such as the first Earth Resources Technology Satellite (ERTS-1) orbited by NASA, allow rapid frequent and accurate general land use inventories that are of value in many types of spatial analyses. In this study, Milwaukee County, Wisconsin was classified into several broad land use categories on the basis of computer analysis of four bands of ERTS spectral data (ERTS Frame Number E1017-16093). Categories identified were: (1) road-central business district, (2) grass (green vegetation), (3) suburban, (4) wooded suburb, (5) heavy industry, (6) inner city, and (7) water. Overall, 90 percent accuracy was attained in classification of these urban land use categories.

Todd, W. J.; Mausel, P. E.

1973-01-01

75

Land system architecture: Using land systems to adapt and mitigate global environmental change  

SciTech Connect

Land systems (mosaics of land use and cover) are human environment systems, the changes in which drive and respond to local to global environmental changes, climate to macro-economy (Foley et al., 2005). Changes in land systems have been the principal proximate cause in the loss of habitats and biota globally, long contributed to atmospheric greenhouse gases, and hypothesized to have triggered climate changes in the early Holocene (Ruddiman, 2003). Land use, foremost agriculture, is the largest source of biologically active nitrogen to the atmosphere, critical to sources and sinks of carbon, and a major component in the hydrologic cycle (e.g., Bouwman et al., 2011). Changes in land systems also affect regional climate (Feddema et al., 2005; Pielke, 2005), ecosystem functions, and the array of ecosystem services they provide. Land systems, therefore, are a central feature of how humankind manages its relationship with nature-intended or not, or whether this relationship proceeds sustainably or not.

Turner, B.L.; Janetos, Anthony C.; Verbug, Peter H.; Murray, Alan T.

2013-04-01

76

Crew procedures for microwave landing system operations  

NASA Technical Reports Server (NTRS)

The objective of this study was to identify crew procedures involved in Microwave Landing System (MLS) operations and to obtain a preliminary assessment of crew workload. The crew procedures were identified for three different complements of airborne equipment coupled to an autopilot. Using these three equipment complements, crew tasks were identified for MLS approaches and precision departures and compared to an ILS approach and a normal departure. Workload comparisons between the approaches and departures were made by using a task-timeline analysis program that obtained workload indexes, i.e., the radio of time required to complete the tasks to the time available. The results showed an increase in workload for the MLS scenario for one of the equipment complements. However, even this workload was within the capacity of two crew members.

Summers, Leland G.

1987-01-01

77

Magneto-rheological (MR) damper for landing gear system  

NASA Astrophysics Data System (ADS)

Depending on the different sink speeds, angles of attack and masses; aircraft landing gears could face a wide range of impact conditions which may possibly cause structural damage or failure. Thus, in hard landing scenarios, the landing gear must absorb sufficient energy in order to minimize dynamic stress on the aircraft airframe. Semi-active control systems are the recent potential solutions to overcome these limitations. Among semi-active control strategies, those based on smart fluids such as magneto-rheological (MR) fluids have received recent attraction as their rheological properties can be continuously controlled using magnetic or electric field and they are not sensitive to the contaminants and the temperature variation and also require lower powers. This thesis focuses on modeling of a MR damper for landing gear system and analysis of semi-active controller to attenuate dynamic load and landing impact. First, passive landing gear of a Navy aircraft is modeled and the forces associated with the shock strut are formulated. The passive shock strut is then integrated with a MR valve to design MR shock strut. Here, MR shock strut is integrated with the landing gear system modeled as the 2DOF system and governing equations of motion are derived in order to simulate the dynamics of the system under different impact conditions. Subsequently the inverse model of the MR shock strut relating MR yield stress to the MR shock strut force and strut velocity is formulated. Using the developed governing equations and inverse model, a PID controller is formulated to reduce the acceleration of the system. Controlled performance of the simulated MR landing gear system is demonstrated and compared with that of passive system.

Khani, Mahboubeh

2010-11-01

78

HEADING REFERENCE SYSTEMS FOR LAND VEHICLES  

Microsoft Academic Search

The paper presents designs of several Heading Reference Systems which can be used in land vehicles for determination of their heading. The systems are composed of diverse combinations of gyro, electronic compass and GNSS receiver and employ Kalman filtering algorithms. Chosen simulation results, comparing accuracy of the designed systems, are included in the paper.

Piotr KANIEWSKI

79

Reconciling Cadastral Records in a Dual Land Registration System in  

Microsoft Academic Search

Soon after gaining independence, the Ghana government adopted a deed registration system for recording land ownership. A legislative instrument supported this decision. The deficiencies of the deed registration system resulted in innumerabl e cases of land ownership disputes. Juxtaposed with the official registration system is the customary land tenure system, which authorized custodians of the stool lands to allocate parcels

Collins FOSU; Francis W. DERBY

80

Validation and Verification of Operational Land Analysis Activities at the Air Force Weather Agency  

NASA Technical Reports Server (NTRS)

The NASA developed Land Information System (LIS) is the Air Force Weather Agency's (AFWA) operational Land Data Assimilation System (LDAS) combining real time precipitation observations and analyses, global forecast model data, vegetation, terrain, and soil parameters with the community Noah land surface model, along with other hydrology module options, to generate profile analyses of global soil moisture, soil temperature, and other important land surface characteristics. (1) A range of satellite data products and surface observations used to generate the land analysis products (2) Global, 1/4 deg spatial resolution (3) Model analysis generated at 3 hours

Shaw, Michael; Kumar, Sujay V.; Peters-Lidard, Christa D.; Cetola, Jeffrey

2011-01-01

81

A comparative analysis of the Global Land Cover 2000 and MODIS land cover data sets  

USGS Publications Warehouse

Accurate and up-to-date global land cover data sets are necessary for various global change research studies including climate change, biodiversity conservation, ecosystem assessment, and environmental modeling. In recent years, substantial advancement has been achieved in generating such data products. Yet, we are far from producing geospatially consistent high-quality data at an operational level. We compared the recently available Global Land Cover 2000 (GLC-2000) and MODerate resolution Imaging Spectrometer (MODIS) global land cover data to evaluate the similarities and differences in methodologies and results, and to identify areas of spatial agreement and disagreement. These two global land cover data sets were prepared using different data sources, classification systems, and methodologies, but using the same spatial resolution (i.e., 1 km) satellite data. Our analysis shows a general agreement at the class aggregate level except for savannas/shrublands, and wetlands. The disagreement, however, increases when comparing detailed land cover classes. Similarly, percent agreement between the two data sets was found to be highly variable among biomes. The identified areas of spatial agreement and disagreement will be useful for both data producers and users. Data producers may use the areas of spatial agreement for training area selection and pay special attention to areas of disagreement for further improvement in future land cover characterization and mapping. Users can conveniently use the findings in the areas of agreement, whereas users might need to verify the informaiton in the areas of disagreement with the help of secondary information. Learning from past experience and building on the existing infrastructure (e.g., regional networks), further research is necessary to (1) reduce ambiguity in land cover definitions, (2) increase availability of improved spatial, spectral, radiometric, and geometric resolution satellite data, and (3) develop advanced classification algorithms. ?? 2004 Elsevier Inc. All rights reserved.

Giri, C.; Zhu, Z.; Reed, B.

2005-01-01

82

Improvements on the Instrument Landing System  

Microsoft Academic Search

The present paper deals primarily with CAA contribution to the art of instrument landing systems and is confined to the localizer and glide-path portions of the system. It describes briefly the present standard 8-loop localizer used at most sites as well as some modifications made in the basic localizer concept in order to adapt it to locations where siting problems

W. E. Jackson

1959-01-01

83

New Developments in Instrument Landing System  

Microsoft Academic Search

This paper describes the antenna systems and equipments utilized in providing ICAO Category I, II, and III performance for the Instrument Landing System (ILS). The latest configurations for localizer, glide slope and markers are discussed. A mathematical model employing physical optics techniques and computers for calculating glide slope course bends is also discussed.

Henry H. Butts; Richard H. McFarland

1966-01-01

84

Inertial navigation system for mobile land vehicles  

Microsoft Academic Search

This paper describes a prototype of an inertial navigation system for use in mobile land vehicles, such as cars or mobile robots. The complete system is composed by sensors, their mechanical mount and cabling, these connect to a PC card with local processing and memory, based on a Intel 80C196KC microcontroller. The sensors used were a piezoelectric vibrating gyroscope, two

Jorge Lobo; Paulo Lucas; Jorge Dias; A. Traca de Almeida

1995-01-01

85

Monitoring urban land cover change: An expert system approach to land cover classification  

E-print Network

Monitoring urban land cover change: An expert system approach to land cover classification 2001; accepted 1 March 2001 Abstract The spatial and temporal distribution of land cover with Landsat Thematic Mapper (TM) data to derive a land cover classification for the semiarid Phoenix

Ramsey, Michael

86

Analysis of land use and land cover change in a coastal area of Rio de Janeiro using  

E-print Network

1 Analysis of land use and land cover change in a coastal area of Rio de Janeiro using high opportunities, but require intensive resource management and environmental protection. Land use and land cover. This study quantitatively describes spatiotemporal changes of land use and land cover over the last four

87

Instrument Landing System: Enhanced Model  

Microsoft Academic Search

We know that the ILS system in aircraft navigation have some problems. That when the signals contact some obstructions near airport runway the aircraft receiver makes some mistakes. In this paper we offer some enhanced model to solve these limitations.

Parisa Noshiravani; Arman Rezaee

2010-01-01

88

Spectroradiometric considerations for advanced land observing systems  

NASA Technical Reports Server (NTRS)

Research aimed at improving the inflight absolute radiometric calibration of advanced land observing systems was initiated. Emphasis was on the satellite sensor calibration program at White Sands. Topics addressed include: absolute radiometric calibration of advanced remote sensing; atmospheric effects on reflected radiation; inflight radiometric calibration; field radiometric methods for reflectance and atmospheric measurement; and calibration of field relectance radiometers.

Slater, P. N.

1986-01-01

89

Supervising passenger land-transport systems  

Microsoft Academic Search

In this paper, we propose a supervisory control approach, based on controlled automata concepts, for the planning for online service-operations control of a new class of passenger land-transport systems ( PLanTSs). A PLanTS belongs to a class of dynamic demand-responsive transportation systems. Rapid advances in information and communication technologies are providing a new infrastructural and communications basis upon which higher

Kiam Tian Seow; Michel Pasquier

2004-01-01

90

The Land Use and Land Cover Dichotomy: A Comparison of Two Land Classification Systems in Support of Urban Earth Science Applications  

NASA Technical Reports Server (NTRS)

One is likely to read the terms 'land use' and 'land cover' in the same sentence, yet these concepts have different origins and different applications. Land cover is typically analyzed by earth scientists working with remotely sensed images. Land use is typically studied by urban planners who must prescribe solutions that could prevent future problems. This apparent dichotomy has led to different classification systems for land-based data. The works of earth scientists and urban planning practitioners are beginning to come together in the field of spatial analysis and in their common use of new spatial analysis technology. In this context, the technology can stimulate a common 'language' that allows a broader sharing of ideas. The increasing amount of land use and land cover change challenges the various efforts to classify in ways that are efficient, effective, and agreeable to all groups of users. If land cover and land uses can be identified by remote methods using aerial photography and satellites, then these ways are more efficient than field surveys of the same area. New technology, such as high-resolution satellite sensors, and new methods, such as more refined algorithms for image interpretation, are providing refined data to better identify the actual cover and apparent use of land, thus effectiveness is improved. However, the closer together and the more vertical the land uses are, the more difficult the task of identification is, and the greater is the need to supplement remotely sensed data with field study (in situ). Thus, a number of land classification methods were developed in order to organize the greatly expanding volume of data on land characteristics in ways useful to different groups. This paper distinguishes two land based classification systems, one developed primarily for remotely sensed data, and the other, a more comprehensive system requiring in situ collection methods. The intent is to look at how the two systems developed and how they can work together so that land based information can be shared among different users and compared over time.

McAllister, William K.

2003-01-01

91

Development of a portable precision landing system  

NASA Technical Reports Server (NTRS)

A portable, tactical approach guidance (PTAG) system, based on a novel, X-band, precision approach concept, was developed and flight tested as a part of NASA's Rotorcraft All-Weather Operations Research Program. The system is based on state-of-the-art X-band technology and digital processing techniques. The PTAG airborne hardware consists of an X-band receiver and a small microprocessor installed in conjunction with the aircraft instrument landing system (ILS) receiver. The microprocessor analyzes the X-band, PTAG pulses and outputs ILS compatible localizer and glide slope signals. The ground stations are inexpensive, portable units, each weighing less than 85 lb, including battery, that can be quickly deployed at a landing site. Results from the flight test program show that PTAG has a significant potential for providing tactical aircraft with low cost, portable, precision instrument approach capability.

Davis, T. J.; Clary, G. R.; Macdonald, S. L.

1986-01-01

92

Adaptive Instrument Landing System in Future Air Traffic Control  

Microsoft Academic Search

Civil aviation develops rapidly, to enhance the security and reliability of instrument landing system, adaptive beamforming technology has been proposed to the future air traffic control system, which is a cooperative instrument landing system. Based on adaptive beamforming technology, the feasibility was analyzed in this work. Adaptive signal equations were deduced in adaptive instrument landing system. Localizer beacon can navigate

Yonghtna Li; Bin Yang; Liguo Yang; Zhiqiang He; Kai Niu; Weiling Wu

2006-01-01

93

The land potential knowledge system (LandPKS): Increasing land productivity and resilience  

Technology Transfer Automated Retrieval System (TEKTRAN)

Africa must significantly increase agricultural production to meet the needs of a growing population. Current efforts focus on intensifying production on currently used lands and expanding to un- or under-utilized lands. The success of both strategies requires understanding the land’s potential prod...

94

78 FR 13316 - National Forest System Land Management Planning Directives  

Federal Register 2010, 2011, 2012, 2013, 2014

...National Forest System Land Management Planning Directives AGENCY: Forest Service...Forest System (NFS) land management planning regulation. Issuance of these proposed...including ``RIN 0596-AD06'' or ``planning directives'' on the cover sheet...

2013-02-27

95

77 FR 44144 - National Forest System Land Management Planning; Correction  

Federal Register 2010, 2011, 2012, 2013, 2014

...National Forest System Land Management Planning; Correction AGENCY: Forest Service...National Forest System land management planning rule in the Federal Register, on April...Ecosystem Management Coordination staff's Planning Specialist Regis Terney at...

2012-07-27

96

The Sand Land Soil System and Society  

NASA Astrophysics Data System (ADS)

Worldwide arid soils such as Latterites from African Savannas to the Xeralfs and Xererts of the Mediterranean Basin Ortents and Orthids of Asian Deserts are uniquely different in their strategic roles for utilizing the land in places where a delicate balance between annual climatic cycles and general trends toward desertification predominate Arid lands cover 1 3 of global land surface and contain irreplaceable natural resources with potential productivity of meeting the demands of more than two billion people and serving as sources and sinks of atmospheric CO2 to combat global warming The soil system in these arid areas are being degraded underutilized and kept in a stage of obliviousness due to inadequate public literacy and most importantly in-sufficient scientific evaluations based on pedology and soil taxonomy standards Implementation of food security projects and sustainable development programs on randomly selected sites and assessment of land degradation worldwide by powerful computers and satellite imagery techniques without field work and identification of Representative Soil Units are data producing and grant attracting but counter productive We live in a world in which there is an order out there and things are precisely measured and categorized for efficient utilization Why not the soils mainly in arid areas How we could generalize the world of soils under our feet by concept of soils are the same Expansion of educational programs quantification of multiple ecosystems within the arid regions through detailed and correlated

Mahjoory, R. A.

97

Spatiotemporal analysis of land use and land cover change in the Brazilian Amazon  

PubMed Central

This paper provides a comparative analysis of land use and land cover (LULC) changes among three study areas with different biophysical environments in the Brazilian Amazon at multiple scales, from per-pixel, polygon, census sector, to study area. Landsat images acquired in the years of 1990/1991, 1999/2000, and 2008/2010 were used to examine LULC change trajectories with the post-classification comparison approach. A classification system composed of six classes – forest, savanna, other-vegetation (secondary succession and plantations), agro-pasture, impervious surface, and water, was designed for this study. A hierarchical-based classification method was used to classify Landsat images into thematic maps. This research shows different spatiotemporal change patterns, composition and rates among the three study areas and indicates the importance of analyzing LULC change at multiple scales. The LULC change analysis over time for entire study areas provides an overall picture of change trends, but detailed change trajectories and their spatial distributions can be better examined at a per-pixel scale. The LULC change at the polygon scale provides the information of the changes in patch sizes over time, while the LULC change at census sector scale gives new insights on how human-induced activities (e.g., urban expansion, roads, and land use history) affect LULC change patterns and rates. This research indicates the necessity to implement change detection at multiple scales for better understanding the mechanisms of LULC change patterns and rates. PMID:24127130

Li, Guiying; Moran, Emilio; Hetrick, Scott

2013-01-01

98

The Auto-Tuned Land Data Assimilation System (ATLAS)  

NASA Astrophysics Data System (ADS)

Land data assimilation systems are commonly tasked with merging remotely sensed surface soil moisture retrievals with information derived from a soil water balance model driven by observed rainfall. The performance of such systems can be degraded by the incorrect specification of parameters describing modeling and observation errors. Here the Auto-Tuned Land Data Assimilation System (ATLAS) is introduced to simultaneously solve for all parameters required for the application of a simple land data assimilation system to integrate satellite-based rainfall and soil moisture retrievals for drought monitoring applications. The approach is based on combining a triple collocation (TC) strategy with the statistical analysis of filtering innovations and designed to leverage the simultaneous availability of satellite-based soil moisture products acquired from both active and passive microwave remote sensing. A number of variants of the ATLAS approach—each based on a different strategy for leveraging TC and innovation analysis within an adaptive filtering framework—are derived and evaluated through a synthetic twin experiment. In addition, a preliminary real data analysis is conducted using actual satellite-based products and evaluated against independent ground-based observations. Results illustrate the potential of ATLAS to improve the analysis of soil moisture anomalies using data products derived from the Global Precipitation Measurement (GPM) and the NASA Soil Moisture Active/Passive missions.

Crow, W. T.; Yilmaz, M. Tugrul

2014-01-01

99

Video guidance, landing, and imaging systems  

NASA Technical Reports Server (NTRS)

The adaptive potential of video guidance technology for earth orbital and interplanetary missions was explored. The application of video acquisition, pointing, tracking, and navigation technology was considered to three primary missions: planetary landing, earth resources satellite, and spacecraft rendezvous and docking. It was found that an imaging system can be mechanized to provide a spacecraft or satellite with a considerable amount of adaptability with respect to its environment. It also provides a level of autonomy essential to many future missions and enhances their data gathering ability. The feasibility of an autonomous video guidance system capable of observing a planetary surface during terminal descent and selecting the most acceptable landing site was successfully demonstrated in the laboratory. The techniques developed for acquisition, pointing, and tracking show promise for recognizing and tracking coastlines, rivers, and other constituents of interest. Routines were written and checked for rendezvous, docking, and station-keeping functions.

Schappell, R. T.; Knickerbocker, R. L.; Tietz, J. C.; Grant, C.; Rice, R. B.; Moog, R. D.

1975-01-01

100

Surface Landing Site Weather Analysis for NASA's Constellation Program  

NASA Technical Reports Server (NTRS)

Weather information is an important asset for NASA's Constellation Program in developing the next generation space transportation system to fly to the International Space Station, the Moon and, eventually, to Mars. Weather conditions can affect vehicle safety and performance during multiple mission phases ranging from pre-launch ground processing of the Ares vehicles to landing and recovery operations, including all potential abort scenarios. Meteorological analysis is art important contributor, not only to the development and verification of system design requirements but also to mission planning and active ground operations. Of particular interest are the surface weather conditions at both nominal and abort landing sites for the manned Orion capsule. Weather parameters such as wind, rain, and fog all play critical roles in the safe landing of the vehicle and subsequent crew and vehicle recovery. The Marshall Space Flight Center (MSFC) Natural Environments Branch has been tasked by the Constellation Program with defining the natural environments at potential landing zones. This paper wiI1 describe the methodology used for data collection and quality control, detail the types of analyses performed, and provide a sample of the results that cab be obtained.

Altino, Karen M.; Burns, K. L.

2008-01-01

101

Flight test evaluation of microwave landing system airborne antennas  

Microsoft Academic Search

of a new approach and landing guidance system that will utilize C-band and possibly Ku-band microwave frequencies. This Microwave Landing System (MU) will eventually replace the Instrument Landing System (ILS) currently in use at airports today. New airborne antenna designs and locations for most commercial and military aircraft will be required. Previously, most airborne antenna designs have been based primarily

Melvin C. Gilreath; William F. White

1978-01-01

102

AGFATL- ACTIVE GEAR FLEXIBLE AIRCRAFT TAKEOFF AND LANDING ANALYSIS  

NASA Technical Reports Server (NTRS)

The Active Gear, Flexible Aircraft Takeoff and Landing Analysis program, AGFATL, was developed to provide a complete simulation of the aircraft takeoff and landing dynamics problem. AGFATL can represent an airplane either as a rigid body with six degrees of freedom or as a flexible body with multiple degrees of freedom. The airframe flexibility is represented by the superposition of up to twenty free vibration modes on the rigid-body motions. The analysis includes maneuver logic and autopilots programmed to control the aircraft during glide slope, flare, landing, and takeoff. The program is modular so that performance of the aircraft in flight and during landing and ground maneuvers can be studied separately or in combination. A program restart capability is included in AGFATL. Effects simulated in the AGFATL program include: (1) flexible aircraft control and performance during glide slope, flare, landing roll, and takeoff roll under conditions of changing winds, engine failures, brake failures, control system failures, strut failures, restrictions due to runway length, and control variable limits and time lags; (2) landing gear loads and dynamics for up to five gears; (3) single and multiple engines (maximum of four) including selective engine reversing and failure; (4) drag chute and spoiler effects; (5) wheel braking (including skid-control) and selective brake failure; (6) aerodynamic ground effects; (7) aircraft carrier operations; (8) inclined runways and runway perturbations; (9) flexible or rigid airframes; 10) rudder and nose gear steering; and 11) actively controlled landing gear shock struts. Input to the AGFATL program includes data which describe runway roughness; vehicle geometry, flexibility and aerodynamic characteristics; landing gear(s); propulsion; and initial conditions such as attitude, attitude change rates, and velocities. AGFATL performs a time integration of the equations of motion and outputs comprehensive information on the airframe, state-of-maneuver logic, autopilots, control response, and aircraft loads from impact, runway roll-out, and ground operations. Flexible-body and total (elastic plus rigid-body) displacements, velocities, and accelerations are also output in the flexible-body option for up to twenty points on the aircraft. The AGFATL program is written in FORTRAN IV for batch execution and has been implemented on a CDC CYBER 170 series computer with an overlayed central memory requirement of approximately 141 (octal) of 60 bit words. The AGFATL program was last updated in 1984.

Mcgehee, J. R.

1994-01-01

103

Quantitative Geomorphological Analysis & Land Use/ Land Cover Change Detection of Two Sub-Watersheds in NE region of Punjab, India  

NASA Astrophysics Data System (ADS)

Morphometric analysis is the measurement and mathematical analysis of the landforms. The delineation of drainage system is of utmost importance in understanding hydrological system of an area, water resource management and it's planning in an effective manner. Morphometric analysis and land use change detection of two sub-watersheds namely Kukar Suha and Ratewal of district Shahid Bhagat Singh Nagar, Punjab, India was carried out for quantitative description of drainage and characterisation. The stream order, stream number, stream length, mean stream length, and other morphometric analysis like bifurcation ratio, drainage density, texture, relief ratio, ruggedness number etc. were measured. The drainage pattern of Kukar Suha and Ratewal is mainly dendritic. The agriculture and settlements came up along the drainage network causes the pattern disturbance in the watershed. The study was undertaken to spotlight the morphometric parameters, their impact on the basin and the land use land cover changes occurred over the period of time. Morphometric parameters such as linear aspect, areal aspect and relief aspect of the watershed are computed. The land use/land cover change was extracted from LISS IV Mx + Cartosat1 PAN data. ASTER data is used to prepare DEM (digital elevation model) and geographical information system (GIS) was used to evaluate various morphometric parameters in ArcGIS10 software.

Kaur, M.; Singh, S.; Verma, V. K.; Pateriya, B.

2014-11-01

104

Louisiana comprehensive planning information system. [computerized land use mapping system  

NASA Technical Reports Server (NTRS)

A statewide computerized land use mapping system is reported that uses polygons to identify inventories from aerial photography by employing the USGS classification system. In addition, the system provides soil, population, and housing census data as well as economic indicators that can be useful in relating to the overall system.

Ryan, P. W.; Schwertz, E.

1975-01-01

105

Nuclear instrument landing system. Phase II interim report covering the period June 1971January 1973  

Microsoft Academic Search

The analysis, design, construction, and field tests of a prototype ; Nuclear lnstrument Landing System (NILS) are rcported. NILS is designed as a ; short range guidance system for providing highly accurate aircraft position ; information durirg the last phases of descent and touchdown for completely ; automated landings in zero visibility weather. The NILS consists of ground and ;

Kaminskas

1973-01-01

106

A new digital land mobile satellite system  

NASA Astrophysics Data System (ADS)

A description is given of the different digital services planned to be carried over existing and planned mobile satellite systems. These systems are then compared with analog services in terms of bandwidth and power efficiency. This comparison provides the rationale for the establishment of a digital land mobile satellite service (DLMSS) to use frequencies that are currently available but not yet assigned to a domestic mobile satellite system in the United States. The focus here is on the expected advantages of digital transmission techniques in accommodating additional mobile satellite systems in this portion of the spectrum, and how such techniques can fully satisfy voice, data and facsimile mobile communications requirements in a cost effective manner. A description is given of the system architecture of the DMLSS service proposed by the Geostar Messaging Corporation (GMC) and the market potential of DLMSS.

Schneider, Philip

107

A new digital land mobile satellite system  

NASA Technical Reports Server (NTRS)

A description is given of the different digital services planned to be carried over existing and planned mobile satellite systems. These systems are then compared with analog services in terms of bandwidth and power efficiency. This comparison provides the rationale for the establishment of a digital land mobile satellite service (DLMSS) to use frequencies that are currently available but not yet assigned to a domestic mobile satellite system in the United States. The focus here is on the expected advantages of digital transmission techniques in accommodating additional mobile satellite systems in this portion of the spectrum, and how such techniques can fully satisfy voice, data and facsimile mobile communications requirements in a cost effective manner. A description is given of the system architecture of the DMLSS service proposed by the Geostar Messaging Corporation (GMC) and the market potential of DLMSS.

Schneider, Philip

1990-01-01

108

Flight safety performance of the microwave landing system  

Microsoft Academic Search

The microwave landing system (MLS), which is scheduled to be implemented progressively over the next 10 years, is intended to supply the instrument landing system (ILS) as the international standard landing aid. MLS has been demonstrated to be superior to ILS from both performance and reliability standpoints, yet considerable debate persists on its relative merits. Although tolerance criteria for flight

Daniel J. Berninger; Cantillion Boulevard; Mays Landing

1990-01-01

109

Airplane takeoff and landing performance monitoring system  

NASA Technical Reports Server (NTRS)

The invention is a real-time takeoff and landing performance monitoring system for an aircraft which provides a pilot with graphic and metric information to assist in decisions related to achieving rotation speed (VR) within the safe zone of a runway, or stopping the aircraft on the runway after landing or take-off abort. The system processes information in two segments: a pretakeoff segment and a real-time segment. One-time inputs of ambient conditions and airplane configuration information are used in the pretakeoff segment to generate scheduled performance data. The real-time segment uses the scheduled performance data, runway length data and transducer measured parameters to monitor the performance of the airplane throughout the takeoff roll. Airplane acceleration and engine-performance anomalies are detected and annunciated. A novel and important feature of this segment is that it updates the estimated runway rolling friction coefficient. Airplane performance predictions also reflect changes in head wind occurring as the takeoff roll progresses. The system provides a head-down display and a head-up display. The head-up display is projected onto a partially reflective transparent surface through which the pilot views the runway. By comparing the present performance of the airplane with a continually predicted nominal performance based upon given conditions, performance deficiencies are detected by the system and conveyed to pilot in form of both elemental information and integrated information.

Middleton, David B. (inventor); Srivatsan, Raghavachari (inventor); Person, Lee H., Jr. (inventor)

1994-01-01

110

Airplane takeoff and landing performance monitoring system  

NASA Technical Reports Server (NTRS)

The invention is a real-time takeoff and landing performance monitoring system for an aircraft which provides a pilot with graphic and metric information to assist in decisions related to achieving rotation speed (V.sub.R) within the safe zone of a runway, or stopping the aircraft on the runway after landing or take-off abort. The system processes information in two segments: a pretakeoff segment and a real-time segment. One-time inputs of ambient conditions and airplane configuration information are used in the pretakeoff segment to generate scheduled performance data. The real-time segment uses the scheduled performance data, runway length data and transducer measured parameters to monitor the performance of the airplane throughout the takeoff roll. Airplane acceleration and engine-performance anomalies are detected and annunciated. A novel and important feature of this segment is that it updates the estimated runway rolling friction coefficient. Airplane performance predictions also reflect changes in head wind occurring as the takeoff roll progresses. The system provides a head-down display and a head-up display. The head-up display is projected onto a partially reflective transparent surface through which the pilot views the runway. By comparing the present performance of the airplane with a continually predicted nominal performance based upon given conditions, performance deficiencies are detected by the system and conveyed to pilot in form of both elemental information and integrated information.

Middleton, David B. (Inventor); Srivatsan, Raghavachari (Inventor); Person, Jr., Lee H. (Inventor)

1996-01-01

111

Airplane takeoff and landing performance monitoring system  

NASA Technical Reports Server (NTRS)

The invention is a real-time takeoff and landing performance monitoring system for an aircraft which provides a pilot with graphic and metric information to assist in decisions related to achieving rotation speed (V.sub.R) within the safe zone of a runway, or stopping the aircraft on the runway after landing or take-off abort. The system processes information in two segments: a pretakeoff segment and a real-time segment. One-time inputs of ambient conditions and airplane configuration information are used in the pretakeoff segment to generate scheduled performance data. The real-time segment uses the scheduled performance data, runway length data and transducer measured parameters to monitor the performance of the airplane throughout the takeoff roll. Airplane and engine performance deficiencies are detected and annunciated. A novel and important feature of this segment is that it updates the estimated runway rolling friction coefficient. Airplane performance predictions also reflect changes in head wind occurring as the takeoff roll progresses. The system provides a head-down display and a head-up display. The head-up display is projected onto a partially reflective transparent surface through which the pilot views the runway. By comparing the present performance of the airplane with a predicted nominal performance based upon given conditions, performance deficiencies are detected by the system.

Middleton, David B. (Inventor); Srivatsan, Raghavachari (Inventor); Person, Jr., Lee H. (Inventor)

1991-01-01

112

Shortle and Jeddi 1 Probabilistic Analysis of Wake Vortex Hazards for Landing Aircraft Using Multilateration  

E-print Network

Instrument Flight Rules (IFR) between two landing aircraft at the runway threshold is between 2.5 and 6Shortle and Jeddi 1 Probabilistic Analysis of Wake Vortex Hazards for Landing Aircraft Using Multilateration Data John F. Shortle* Systems Engineering and Operations Research George Mason University 4400

113

Global Land Project: Major Scientific Questions for Coupled Modeling of Land Systems  

Microsoft Academic Search

This chapter describes some scientific challenges for coupled modeling of land systems at the interface of human and environmental\\u000a systems. These include examining the character and operation of drivers of change and processes representation of drivers\\u000a in models. A variety of examples of land use change, primarily from rural areas, are used to examine drivers of land use change\\u000a and

Richard Aspinall

114

Analysis of Land Suitable for Algae State of Hawaii  

E-print Network

Analysis of Land Suitable for Algae Production State of Hawaii Prepared for the U.S. Department agency thereof. #12;Analysis of Land Suitable for Algae Production State of Hawaii Prepared by Mele University of Hawaii at Manoa August 2011 #12;i Executive Summary Algae are considered to be a viable crop

115

Surface Landing Site Weather Analysis for Constellation Program  

NASA Technical Reports Server (NTRS)

Weather information is an important asset for NASA's Constellation Program in developing the next generation space transportation system to fly to the International Space Station, the Moon and, eventually, to Mars. Weather conditions can affect vehicle safety and performance during multiple mission phases ranging from pre-launch ground processing to landing and recovery operations, including all potential abort scenarios. Meteorological analysis is an important contributor, not only to the development and verification of system design requirements but also to mission planning and active ground operations. Of particular interest are the surface atmospheric conditions at both nominal and abort landing sites for the manned Orion capsule. Weather parameters such as wind, rain, and fog all play critical roles in the safe landing of the vehicle and subsequent crew and vehicle recovery. The Marshall Space Flight Center Natural Environments Branch has been tasked by the Constellation Program with defining the natural environments at potential landing zones. Climatological time series of operational surface weather observations are used to calculate probabilities of occurrence of various sets of hypothetical vehicle constraint thresholds, Data are available for numerous geographical locations such that statistical analysis can be performed for single sites as well as multiple-site network configurations. Results provide statistical descriptions of how often certain weather conditions are observed at the site(s) and the percentage that specified criteria thresholds are matched or exceeded. Outputs are tabulated by month and hour of day to show both seasonal and diurnal variation. This paper will describe the methodology used for data collection and quality control, detail the types of analyses performed, and provide a sample of the results that can be obtained,

Altino, Karen M.; Burns, K. Lee

2008-01-01

116

The Pilot Land Data System: Report of the Program Planning Workshops  

NASA Technical Reports Server (NTRS)

An advisory report to be used by NASA in developing a program plan for a Pilot Land Data System (PLDS) was developed. The purpose of the PLDS is to improve the ability of NASA and NASA sponsored researchers to conduct land-related research. The goal of the planning workshops was to provide and coordinate planning and concept development between the land related science and computer science disciplines, to discuss the architecture of the PLDs, requirements for information science technology, and system evaluation. The findings and recommendations of the Working Group are presented. The pilot program establishes a limited scale distributed information system to explore scientific, technical, and management approaches to satisfying the needs of the land science community. The PLDS paves the way for a land data system to improve data access, processing, transfer, and analysis, which land sciences information synthesis occurs on a scale not previously permitted because of limits to data assembly and access.

1984-01-01

117

Inferring Land Surface Model Parameters for the Assimilation of Satellite-Based L-Band Brightness Temperature Observations into a Soil Moisture Analysis System  

NASA Technical Reports Server (NTRS)

The Soil Moisture and Ocean Salinity (SMOS) satellite mission provides global measurements of L-band brightness temperatures at horizontal and vertical polarization and a variety of incidence angles that are sensitive to moisture and temperature conditions in the top few centimeters of the soil. These L-band observations can therefore be assimilated into a land surface model to obtain surface and root zone soil moisture estimates. As part of the observation operator, such an assimilation system requires a radiative transfer model (RTM) that converts geophysical fields (including soil moisture and soil temperature) into modeled L-band brightness temperatures. At the global scale, the RTM parameters and the climatological soil moisture conditions are still poorly known. Using look-up tables from the literature to estimate the RTM parameters usually results in modeled L-band brightness temperatures that are strongly biased against the SMOS observations, with biases varying regionally and seasonally. Such biases must be addressed within the land data assimilation system. In this presentation, the estimation of the RTM parameters is discussed for the NASA GEOS-5 land data assimilation system, which is based on the ensemble Kalman filter (EnKF) and the Catchment land surface model. In the GEOS-5 land data assimilation system, soil moisture and brightness temperature biases are addressed in three stages. First, the global soil properties and soil hydraulic parameters that are used in the Catchment model were revised to minimize the bias in the modeled soil moisture, as verified against available in situ soil moisture measurements. Second, key parameters of the "tau-omega" RTM were calibrated prior to data assimilation using an objective function that minimizes the climatological differences between the modeled L-band brightness temperatures and the corresponding SMOS observations. Calibrated parameters include soil roughness parameters, vegetation structure parameters, and the single scattering albedo. After this climatological calibration, the modeling system can provide L-band brightness temperatures with a global mean absolute bias of less than 10K against SMOS observations, across multiple incidence angles and for horizontal and vertical polarization. Third, seasonal and regional variations in the residual biases are addressed by estimating the vegetation optical depth through state augmentation during the assimilation of the L-band brightness temperatures. This strategy, tested here with SMOS data, is part of the baseline approach for the Level 4 Surface and Root Zone Soil Moisture data product from the planned Soil Moisture Active Passive (SMAP) satellite mission.

Reichle, Rolf H.; De Lannoy, Gabrielle J. M.

2012-01-01

118

Impact of Land Surface Initialization Approach on Subseasonal Forecast Skill: A Regional Analysis in the Southern Hemisphere  

E-print Network

Impact of Land Surface Initialization Approach on Subseasonal Forecast Skill: A Regional Analysis The authors use a sophisticated coupled land­atmosphere modeling system for a Southern Hemisphere subdomain centered over southeastern Australia to evaluate differences in simulation skill from two different land

Evans, Jason

119

Land System Science: between global challenges and local realities?  

PubMed Central

This issue of Current Opinion in Environmental Sustainability provides an overview of recent advances in Land System Science while at the same time setting the research agenda for the Land System Science community. Land System Science is not just representing land system changes as either a driver or a consequence of global environmental change. Land systems also offer solutions to global change through adaptation and mitigation and can play a key role in achieving a sustainable future earth. The special issue assembles 14 articles that entail different perspectives on land systems and their dynamics, synthesizing current knowledge, highlighting currently under-researched topics, exploring scientific frontiers and suggesting ways ahead, integrating a plethora of scientific disciplines. PMID:24851141

Verburg, Peter H; Erb, Karl-Heinz; Mertz, Ole; Espindola, Giovana

2013-01-01

120

Extensible Modular Landing Systems for Human Moon and Mars Exploration  

E-print Network

Extensible Modular Landing Systems for Human Moon and Mars Exploration by Wilfried Hofstetter and Proposed Moon and Mars Exploration System architectures...... 27 2.1.1 The Apollo System...................................................................................... 54 3. Moon and Mars System Architectures Point Designs

de Weck, Olivier L.

121

Land surface model spin-up behavior in the North American Land Data Assimilation System (NLDAS)  

E-print Network

Land surface model spin-up behavior in the North American Land Data Assimilation System (NLDAS; published 21 November 2003. [1] The process of a model adjusting to its forcing (model spin-up) can severely the spin-up process. To gain a better understanding of how spin-up processes affect complex spatial

Robock, Alan

122

Saab NINS\\/NILS-an autonomons landing system for Gripen  

Microsoft Academic Search

This paper presents a new approach for integrated landing systems. Applicable avionics platforms are military aircraft, helicopters, and unmanned aerial vehicles. In this paper we focus on the introduction of NILS (new integrated landing system) in the Saab fourth generation fighter JAS39 Gripen. NILS is based on an integrated navigation system (NINS) which is covered in the paper as well.

P. Pucar; J. Palmqvist

2000-01-01

123

Land Cover Analysis of Temperate Asia  

NASA Technical Reports Server (NTRS)

Satellite data from the advanced very high resolution radiometer (AVHRR) instrument were used to produce a general land cover distribution of temperate Asia (referred to hence as Central Asia) from 1982, starting with the NOAA-7 satellite, and continuing through 1991, ending with the NOAA-11 satellite. Emphasis was placed upon delineating the and and semi-arid zones of Central Asia (largely Mongolia and adjacent areas), mapping broad categories of aggregated land cover, and upon studying photosynthetic capacity increases in Central Asia from 1982 to 1991.

Justice, Chris

1998-01-01

124

Incorporating JULES into NASA's Land Information System (LIS) and Investigations of Land-Atmosphere Coupling  

NASA Technical Reports Server (NTRS)

NASA's Land Information System (LIS; lis.gsfc.nasa.gov) is a flexible land surface modeling and data assimilation framework developed over the past decade with the goal of integrating satellite- and ground-based observational data products and advanced land surface modeling techniques to produce optimal fields of land surface states and fluxes. LIS features a high performance and flexible design, and operates on an ensemble of land surface models for extension over user-specified regional or global domains. The extensible interfaces of LIS allow the incorporation of new domains, land surface models (LSMs), land surface parameters, meteorological inputs, data assimilation and optimization algorithms. In addition, LIS has also been demonstrated for parameter estimation and uncertainty estimation, and has been coupled to the Weather Research and Forecasting (WRF) mesoscale model. A visiting fellowship is currently underway to implement JULES into LIS and to undertake some fundamental science on the feedbacks between the land surface and the atmosphere. An overview of the LIS system, features, and sample results will be presented in an effort to engage the community in the potential advantages of LIS-JULES for a range of applications. Ongoing efforts to develop a framework for diagnosing land-atmosphere coupling will also be presented using the suite of LSM and PBL schemes available in LIS and WRF along with observations from the U. S .. Southern Great Plains. This methodology provides a potential pathway to study factors controlling local land-atmosphere coupling (LoCo) using the LIS-WRF system, which will serve as a testbed for future experiments to evaluate coupling diagnostics within the community.

Santanello, Joseph

2011-01-01

125

Land Condition -Trend Analysis Data Dictionary  

E-print Network

Collins, CO 80523 (303) 491-2748 #12;William Sprouse is a Database Analyst with the Center for Ecological RELATIONAL DATABASE 2 DOCUMENT SYNTAX AND TERMINOLOGY 2 PLOT INFORMATION 3 LAND USE DATA 4 VEGETATION DATA 4 FLORISTIC INVENTORY 7 WILDLIFE INVENTORY 8 BIRDS (STANDARD) 8 SMALL MAMMALS (STANDARD) 9 REPTILES

126

High accuracy navigation and landing system using GPS\\/IMU system integration  

Microsoft Academic Search

In this paper, the accuracy, integrity and continuity of function requirements for automatic landing systems using satellite navigation systems are discussed. Such a landing system is the integrated navigation and landing system (INLS) developed by Deutsche Aerospace (DASA\\/Ulm, Germany). The system concepts of the INLS are presented. It is shown how an INLS, based on system integration of a satellite

J. Meyer-Hilberg; T. Jacob

1994-01-01

127

A land use and land cover classification system for use with remote sensor data  

USGS Publications Warehouse

The framework of a national land use and land cover classification system is presented for use with remote sensor data. The classification system has been developed to meet the needs of Federal and State agencies for an up-to-date overview of land use and land cover throughout the country on a basis that is uniform in categorization at the more generalized first and second levels and that will be receptive to data from satellite and aircraft remote sensors. The proposed system uses the features of existing widely used classification systems that are amenable to data derived from remote sensing sources. It is intentionally left open-ended so that Federal, regional, State, and local agencies can have flexibility in developing more detailed land use classifications at the third and fourth levels in order to meet their particular needs and at the same time remain compatible with each other and the national system. Revision of the land use classification system as presented in U.S. Geological Survey Circular 671 was undertaken in order to incorporate the results of extensive testing and review of the categorization and definitions.

Anderson, James R.; Hardy, Ernest E.; Roach, John T.; Witmer, Richard E.

1976-01-01

128

Trade-off analysis in the Northern Andes to study the dynamics in agricultural land use.  

PubMed

In this paper we hypothesize that land use change can be induced by non-linearities and thresholds in production systems that impact farmers' decision making. Tradeoffs between environmental and economic indicators is a useful way to represent dynamic properties of agricultural systems. The Tradeoff Analysis (TOA) System is software designed to implement the integrated analysis of tradeoffs in agricultural systems. The TOA methodology is based on spatially explicit econometric simulation models linked to spatially referenced bio-physical simulation models to simulate land use and input decisions. The methodology has been applied for the potato-pasture production system in the Ecuadorian Andes. The land use change literature often describes non-linearity in land use change as a result of sudden changes in the political (e.g. new agricultural policies) or environmental setting (e.g. earthquakes). However, less attention has been paid to the non-linearities in production systems and their consequences for land use change. In this paper, we use the TOA system to study agricultural land use dynamics and to find the underlying processes for non-linearities. Results show that the sources of non-linearities are in the properties of bio-physical processes and in the decision making-process of farmers. PMID:15246571

Stoorvogel, J J; Antle, J M; Crissman, C C

2004-08-01

129

Preprint 11-June-2003: Encyclopedia of Life Support Systems (EOLSS)1 Section 1.5 "Land Use and Land Cover"  

E-print Network

1 Preprint 11-June-2003: Encyclopedia of Life Support Systems (EOLSS)1 Section 1.5 "Land Use .................................................... 9 7 Critical issues in using dynamic simulation models for land evaluation and Land Cover" Topic 1.5.27 "Biophysical Models in Land Evaluation" Copyright " 2003 by EOLSS Publishers

Rossiter, D G "David"

130

Cross-Site Comparison of Land-Use Decision-Making and Its Consequences across Land Systems with a  

E-print Network

Cross-Site Comparison of Land-Use Decision-Making and Its Consequences across Land Systems, Maryland, United States of America Abstract Local changes in land use result from the decisions and actions a general understanding of how local decision-making shapes land-use changes at the global scale. This paper

Ellis, Erle C.

131

A meta-analysis of global urban land expansion.  

PubMed

The conversion of Earth's land surface to urban uses is one of the most irreversible human impacts on the global biosphere. It drives the loss of farmland, affects local climate, fragments habitats, and threatens biodiversity. Here we present a meta-analysis of 326 studies that have used remotely sensed images to map urban land conversion. We report a worldwide observed increase in urban land area of 58,000 km(2) from 1970 to 2000. India, China, and Africa have experienced the highest rates of urban land expansion, and the largest change in total urban extent has occurred in North America. Across all regions and for all three decades, urban land expansion rates are higher than or equal to urban population growth rates, suggesting that urban growth is becoming more expansive than compact. Annual growth in GDP per capita drives approximately half of the observed urban land expansion in China but only moderately affects urban expansion in India and Africa, where urban land expansion is driven more by urban population growth. In high income countries, rates of urban land expansion are slower and increasingly related to GDP growth. However, in North America, population growth contributes more to urban expansion than it does in Europe. Much of the observed variation in urban expansion was not captured by either population, GDP, or other variables in the model. This suggests that contemporary urban expansion is related to a variety of factors difficult to observe comprehensively at the global level, including international capital flows, the informal economy, land use policy, and generalized transport costs. Using the results from the global model, we develop forecasts for new urban land cover using SRES Scenarios. Our results show that by 2030, global urban land cover will increase between 430,000 km(2) and 12,568,000 km(2), with an estimate of 1,527,000 km(2) more likely. PMID:21876770

Seto, Karen C; Fragkias, Michail; Güneralp, Burak; Reilly, Michael K

2011-01-01

132

A Meta-Analysis of Global Urban Land Expansion  

PubMed Central

The conversion of Earth's land surface to urban uses is one of the most irreversible human impacts on the global biosphere. It drives the loss of farmland, affects local climate, fragments habitats, and threatens biodiversity. Here we present a meta-analysis of 326 studies that have used remotely sensed images to map urban land conversion. We report a worldwide observed increase in urban land area of 58,000 km2 from 1970 to 2000. India, China, and Africa have experienced the highest rates of urban land expansion, and the largest change in total urban extent has occurred in North America. Across all regions and for all three decades, urban land expansion rates are higher than or equal to urban population growth rates, suggesting that urban growth is becoming more expansive than compact. Annual growth in GDP per capita drives approximately half of the observed urban land expansion in China but only moderately affects urban expansion in India and Africa, where urban land expansion is driven more by urban population growth. In high income countries, rates of urban land expansion are slower and increasingly related to GDP growth. However, in North America, population growth contributes more to urban expansion than it does in Europe. Much of the observed variation in urban expansion was not captured by either population, GDP, or other variables in the model. This suggests that contemporary urban expansion is related to a variety of factors difficult to observe comprehensively at the global level, including international capital flows, the informal economy, land use policy, and generalized transport costs. Using the results from the global model, we develop forecasts for new urban land cover using SRES Scenarios. Our results show that by 2030, global urban land cover will increase between 430,000 km2 and 12,568,000 km2, with an estimate of 1,527,000 km2 more likely. PMID:21876770

Seto, Karen C.; Fragkias, Michail; Güneralp, Burak; Reilly, Michael K.

2011-01-01

133

A Reusable Design for Precision Lunar Landing Systems  

NASA Technical Reports Server (NTRS)

The top-level architecture to accomplish NASA's Vision for Space Exploration is to use Lunar missions and systems not just as an end in themselves, but also as testbeds for the more ambitious goals of Human Mars Exploration (HME). This approach means that Lunar missions and systems are most likely going to be targeted for (Lunar) polar missions, and also for long-duration (months) surface stays. This overacting theme creates basic top-level requirements for any next-generation lander system: 1) Long duration stays: a) Multiple landers in close proximity; b) Pinpoint landings for "surface rendezvous"; c) Autonomous landing of pre-positioned assets; and d) Autonomous Hazard Detection and Avoidance. 2) Polar and deep-crater landings (dark); 3) Common/extensible systems for Moon and Mars, crew and cargo. These requirements pose challenging technology and capability needs. Compare and contrast: 4) Apollo: a) 1 km landing accuracy; b) Lunar near-side (well imaged and direct-to-Earth com. possible); c) Lunar equatorial (landing trajectories offer best navigation support from Earth); d) Limited lighting conditions; e) Significant ground-in-the-loop operations; 5) Lunar Access: a) 10-100m landing precision; b) "Anywhere" access includes polar (potentially poor nav. support from Earth) and far side (poor gravity and imaging; no direct-to-Earth com); c) "Anytime" access includes any lighting condition (including dark); d) Full autonomous landing capability; e) Extensible design for tele-operation or operator-in-the-loop; and f) Minimal ground support to reduce operations costs. The Lunar Access program objectives, therefore, are to: a) Develop a baseline Lunar Precision Landing System (PLS) design to enable pinpoint "anywhere, anytime" landings; b) landing precision 10m-100m; c) Any LAT, LON; and d) Any lighting condition; This paper will characterize basic features of the next generation Lunar landing system, including trajectory types, sensor suite options and a reference system architecture.

Fuhrman, Linda; Brand, Timothy; Fill, Tom; Norris, Lee; Paschall, Steve

2005-01-01

134

A Vision System for Landing an Unmanned Aerial Vehicle  

Microsoft Academic Search

We present the design ami implementation of a real-time computer vision syslem for a rotor-craft un- manned aerial vehicle to land onto a known land- ing target. This vision system consists of customized software and off-the-shelf harc!ware which perform im- age processing, segmentation, feature point extraction, camera pan\\/tilt control, and motion estimation. We introduce the design of a landing target

Courtney S. Sharp; Orriid Shakernia; S. Shankar Sastry

2001-01-01

135

Post2 End-to-End Descent and Landing Simulation for ALHAT Design Analysis Cycle 2  

NASA Technical Reports Server (NTRS)

The ALHAT project is an agency-level program involving NASA centers, academia, and industry, with a primary goal to develop a safe, autonomous, precision-landing system for robotic and crew-piloted lunar and planetary descent vehicles. POST2 is used as the 6DOF descent and landing trajectory simulation for determining integrated system performance of ALHAT landing-system models and lunar environment models. This paper presents updates in the development of the ALHAT POST2 simulation, as well as preliminary system performance analysis for ALDAC-2 used for the testing and assessment of ALHAT system models. The ALDAC-2 POST2 Monte Carlo simulation results have been generated and focus on HRN model performance with the fully integrated system, as well performance improvements of AGNC and TSAR model since the previous design analysis cycle

Davis, Jody L.; Striepe, Scott A.; Maddock, Robert W.; Johnson, Andrew E.; Paschall, Stephen C., II

2010-01-01

136

SANITARY SEWER SYSTEMS - LAND APPLICATION AREAS, NEUSE RIVER WATERSHED, NC  

EPA Science Inventory

The North Carolina Rural Economic Development Center (NCREDC) in conjunction with Hobbs, Upchurch & Associates developed the digital Sewer system land applications as mapped by individual system owners as required by contract. The data collected will facilitate planning, siting a...

137

Neutron-based land mine detection system development  

SciTech Connect

This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The goal of this project was to examine the feasibility of developing a land mine detection system that can detect nonmetallic (plastic) mines using the detection and analysis of prompt gamma neutron activation analysis (PGNAA). The authors approached this study by first carrying out a review of other nonmetallic land mine detection methods for comparison with the PGNAA concept. They reviewed issues associated with detecting and recording the return gamma signal resulting from neutrons interacting with high explosive in mines and they examined two neutron source technologies that have been under development at Los Alamos for the past several years for possible application to a PGNAA system. A major advantage of the PGNAA approach is it`s ability to discriminate detection speed and need for close proximity. The authors identified approaches to solving these problems through development of improved neutron sources and detection sensors.

Davis, H.A.; McDonald, T.E. Jr.; Nebel, R.A.; Pickrell, M.M.

1997-10-01

138

Historical Overview of the American Land Use System: A Diagnostic Approach to Evaluating Governmental Land Use Control  

Microsoft Academic Search

This article describes how the American land use system has evolved to address recent environmental and economic development problems. It begins by tracing the history of the legal system used in the United States to control private sector land development and demonstrates how it achieved the flexibility needed to respond to modern challenges. The American land use system has paid

John R Nolon

2006-01-01

139

Analysis and design of a capsule landing system and surface vehicle control system for Mars exploration. [performance tests of remote control equipment for roving vehicles  

NASA Technical Reports Server (NTRS)

Problems related to the design and control of an autonomous rover for the purpose of unmanned exploration of the planets were considered. Building on the basis of prior studies, a four wheeled rover of unusual mobility and maneuverability was further refined and tested under both laboratory and field conditions. A second major effort was made to develop autonomous guidance. Path selection systems capable of dealing with relatively formidable hazard and terrains involving various short range (1.0-3.0 meters), hazard detection systems using a triangulation detection concept were simulated and evaluated. The mechanical/electronic systems required to implement such a scheme were constructed and tested. These systems include: laser transmitter, photodetectors, the necessary data handling/controlling systems and a scanning mast. In addition, a telemetry system to interface the vehicle, the off-board computer and a remote control module for operator intervention were developed. Software for the autonomous control concept was written. All of the systems required for complete autonomous control were shown to be satisfactory except for that portion of the software relating to the handling of interrupt commands.

Gisser, D. G.; Frederick, D. K.; Sandor, G. N.; Shen, C. N.; Yerazunis, S. W.

1976-01-01

140

Preliminary analysis of knee stress in Full Extension Landing  

PubMed Central

OBJECTIVE: This study provides an experimental and finite element analysis of knee-joint structure during extended-knee landing based on the extracted impact force, and it numerically identifies the contact pressure, stress distribution and possibility of bone-to-bone contact when a subject lands from a safe height. METHODS: The impact time and loads were measured via inverse dynamic analysis of free landing without knee flexion from three different heights (25, 50 and 75 cm), using five subjects with an average body mass index of 18.8. Three-dimensional data were developed from computed tomography scans and were reprocessed with modeling software before being imported and analyzed by finite element analysis software. The whole leg was considered to be a fixed middle-hinged structure, while impact loads were applied to the femur in an upward direction. RESULTS: Straight landing exerted an enormous amount of pressure on the knee joint as a result of the body's inability to utilize the lower extremity muscles, thereby maximizing the threat of injury when the load exceeds the height-safety threshold. CONCLUSIONS: The researchers conclude that extended-knee landing results in serious deformation of the meniscus and cartilage and increases the risk of bone-to-bone contact and serious knee injury when the load exceeds the threshold safety height. This risk is considerably greater than the risk of injury associated with walking downhill or flexion landing activities. PMID:24141832

Makinejad, Majid Davoodi; Abu Osman, Noor Azuan; Wan Abas, Wan Abu Bakar; Bayat, Mehdi

2013-01-01

141

Operational Flight Testing of Early Instrument Landing Systems  

Microsoft Academic Search

The development of successful instrument approach and landing involved the solution of not only technical problems, but operational problems as well. A review of methods used to overcome operational problems is made, covering the period from the earliest successful instrument landing to the introduction of instrument approach into routine scheduled operation. Flight techniques are described, using early systems such as

E. A. Cutrell

1959-01-01

142

Acquiring observation error covariance information for land data assimilation systems  

Technology Transfer Automated Retrieval System (TEKTRAN)

Recent work has presented the initial application of adaptive filtering techniques to land surface data assimilation systems. Such techniques are motivated by our current lack of knowledge concerning the structure of large-scale error in either land surface modeling output or remotely-sensed estimat...

143

Treatment of systematic errors in land data assimilation systems  

NASA Astrophysics Data System (ADS)

Data assimilation systems are generally designed to minimize the influence of random error on the estimation of system states. Yet, experience with land data assimilation systems has also revealed the presence of large systematic differences between model-derived and remotely-sensed estimates of land surface states. Such differences are commonly resolved prior to data assimilation through implementation of a pre-processing rescaling step whereby observations are scaled (or non-linearly transformed) to somehow "match" comparable predictions made by an assimilation model. While the rationale for removing systematic differences in means (i.e., bias) between models and observations is well-established, relatively little theoretical guidance is currently available to determine the appropriate treatment of higher-order moments during rescaling. This talk presents a simple analytical argument to define an optimal linear-rescaling strategy for observations prior to their assimilation into a land surface model. While a technique based on triple collocation theory is shown to replicate this optimal strategy, commonly-applied rescaling techniques (e.g., so called "least-squares regression" and "variance matching" approaches) are shown to represent only sub-optimal approximations to it. Since the triple collocation approach is likely infeasible in many real-world circumstances, general advice for deciding between various feasible (yet sub-optimal) rescaling approaches will be presented with an emphasis of the implications of this work for the case of directly assimilating satellite radiances. While the bulk of the analysis will deal with linear rescaling techniques, its extension to nonlinear cases will also be discussed.

Crow, W. T.; Yilmaz, M.

2012-12-01

144

Analysis of Land Suitable for Algae State of Hawaii  

E-print Network

Analysis of Land Suitable for Algae Production State of Hawaii Prepared by Mele Chillingworth Scott of Hawaii at Manoa August 2011 #12;i Executive Summary Algae are considered to be a viable crop for biofuel for biofuels has increased interest in growing algae in Hawaii for biofuels. An analysis of algae production

145

Direct-sequence spread spectrum spectral overlay in the instrument landing system glideslope and microwave landing system bands  

Microsoft Academic Search

We compare the performance of direct-sequence spread spectrum (DS-SS) code-division multiple access (CDMA) systems used in spectral overlay mode in two different aeronautical bands: the instrument landing system glideslope (ILS-GS) band, from 329-335 MHz, and the microwave landing system (MLS) band, from 5091-5150 MHz. The purpose of the overlay system is to enable increased spectral efficiency (higher data throughput), for

Joshua T. Neville; David K Matolak

2004-01-01

146

76 FR 81911 - National Advisory Committee for Implementation of the National Forest System Land Management...  

Federal Register 2010, 2011, 2012, 2013, 2014

...National Forest System Land Management Planning Rule AGENCY: USDA Forest Service. ACTION...National Forest System Land Management Planning Rule (Committee). In accordance with...National Forest System Land Management Planning Rule (Planning Rule). The...

2011-12-29

147

Temporal Land Cover Analysis for Net Ecosystem Improvement  

SciTech Connect

We delineated 8 watersheds contributing to previously defined river reaches within the 1,468-km2 historical floodplain of the tidally influenced lower Columbia River and estuary. We assessed land-cover change at the watershed, reach, and restoration site scales by reclassifying remote-sensing data from the National Oceanic and Atmospheric Administration Coastal Change Analysis Program’s land cover/land change product into forest, wetland, and urban categories. The analysis showed a 198.3 km2 loss of forest cover during the first 6 years of the Columbia Estuary Ecosystem Restoration Program, 2001–2006. Total measured urbanization in the contributing watersheds of the estuary during the full 1996-2006 change analysis period was 48.4 km2. Trends in forest gain/loss and urbanization differed between watersheds. Wetland gains and losses were within the margin of error of the satellite imagery analysis. No significant land cover change was measured at restoration sites, although it was visible in aerial imagery, therefore, the 30-m land-cover product may not be appropriate for assessment of early-stage wetland restoration. These findings suggest that floodplain restoration sites in reaches downstream of watersheds with decreasing forest cover will be subject to increased sediment loads, and those downstream of urbanization will experience effects of increased impervious surfaces on hydrologic processes.

Ke, Yinghai; Coleman, Andre M.; Diefenderfer, Heida L.

2013-04-09

148

Applications of Skylab data to land use and climatological analysis  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. Skylab study in Central Atlantic Regional Ecological Test Site encompassed two separate but related tasks: (1) evaluation of photographic sensors S190A and B as sources of land use data for planning and managing land resources in major metropolitan regions, and (2) evaluation of the multispectral scanner S192 used in conjunction with associated data and analytical techniques as a data source on urban climates and the surface energy balance. Photographs from the Skylab S190B earth terrain camera were of greatest interest in the land use analysis task; they were of sufficiently high resolution to identify and map many level 2 and 3 land use categories. After being corrected to allow for atmosphere effects, output from thermal and visible bands of the S192 was employed in constructing computer map plots of albedo and surface temperature.

Alexander, R. H. (principal investigator); Lewis, J. E., Jr.; Lins, H. F., Jr.; Jenner, C. B.; Outcalt, S. I.; Pease, R. W.

1976-01-01

149

Land-use systems and resilience of tropical rain forests in the Tehuantepec Isthmus, Mexico.  

PubMed

Land-cover types were analyzed for 1970, 1990 and 2000 as the bases for determining land-use systems and their influence on the resilience of tropical rain forests in the Tehuantepec Isthmus, Mexico. Deforestation (DR) and mean annual transformation rates were calculated from land-cover change data; thus, the classification of land-use change processes was determined according to their impact on resilience: a) Modification, including land-cover conservation and intensification, and b) Conversion, including disturbance and regeneration processes. Regeneration processes, from secondary vegetation under extensive use, cultivated vegetation under intensive use, and cultivated or induced vegetation under extensive use to mature or secondary vegetation, have high resilience capacity. In contrast, cattle-raising is characterized by rapid expansion, long-lasting change, and intense damages; thus, recent disturbance processes, which include the conversion to cattle-raising, provoke the downfall of the traditional agricultural system, and nullify the capacity of resilience of tropical rain forest. The land-use cover change processes reveal a) the existence of four land-use systems (forestry, extensive agriculture, extensive cattle-raising, and intensive uses) and b) a trend towards the replacement of agricultural and forestry systems by extensive cattle-raising, which was consolidated during 1990-2000 (DR of evergreen tropical rain forest = 4.6%). Only the forestry system, which is not subject to deforestation, but is affected by factors such as selective timber, extraction, firewood collection, grazing, or human-induced fire, is considered to have high resilience (2 years), compared to agriculture (2-10 years) or cattle-raising (nonresilient). It is concluded that the analysis of land-use systems is essential for understanding the implications of land-use cover dynamics on forest recovery and land degradation in tropical rain forests. PMID:15726281

García-Romero, Arturo; Oropeza-Orozco, Oralia; Galicia-Sarmiento, Leopoldo

2004-12-01

150

Aeroacoustic Analysis of a Simplified Landing Gear  

NASA Technical Reports Server (NTRS)

A hybrid approach is used to investigate the noise generated by a simplified landing gear without small scale parts such as hydraulic lines and fasteners. The Ffowcs Williams and Hawkings equation is used to predict the noise at far-field observer locations from flow data provided by an unsteady computational fluid dynamics calculation. A simulation with 13 million grid points has been completed, and comparisons are made between calculations with different turbulence models. Results indicate that the turbulence model has a profound effect on the levels and character of the unsteadiness. Flow data on solid surfaces and a set of permeable surfaces surrounding the gear have been collected. Noise predictions using the porous surfaces appear to be contaminated by errors caused by large wake fluctuations passing through the surfaces. However, comparisons between predictions using the solid surfaces with the near-field CFD solution are in good agreement giving confidence in the far-field results.

Lockard, David P.; Khorrami, Mehdi, R.; Li, Fei

2004-01-01

151

Quantitative Change and Use Analysis of Agricultural Land in China  

NASA Astrophysics Data System (ADS)

Climatic change, economic and scientific development and political guidance irritate the change of land use. With the index of crop sown area, this paper mainly explores the agricultural land use situation in these years of China. Accumulated temperature and urbanization rate are used to analyze space-time difference and its impact mechanism of crop sown area, for the quantitative change of agricultural land. While cropping index reflected agricultural land use is considered to obtain the actual use of cultivated land and its surplus capacity. Some results are concluded as follows: (1) from 1949 to 2010, crop sown area has a generally slow growth in China, however, with obvious space diversity. Most quickly increase and decrease are reflected in Xinjiang and North China, and the size of agricultural land ranks from the midland to the east and to the west of China. (2) Based on the relationship of accumulated temperature and cropping system, effect of climatic change, urbanization and other factors aggregated on crop sown area increase are considered. It is confirmed that warming promotes much little, urbanization restrains mainly in South China, northeast China, Xinjiang and southwest China, and other factors aggregated accelerate agricultural land of the rest of China. (3) From 1980 to 2009, agricultural land use degree keeps unceasing deepening. By the common influence of decreased cultivated area and less potential cropping index than actual cropping index, surplus capacity of cultivated area induces, from 6.27*107 hm2 in 1980 to 3.85*107 hm2 in 2009. However, it still accounts for about 20 percent of agricultural land to the full potential, which verifies the necessary of sufficient and reasonable use in further.

Fu, Y.; Chou, J.; Dong, W.

2013-12-01

152

7. Northeast view interior, air traffic control and landing system ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. Northeast view interior, air traffic control and landing system room 25 - Selfridge Field, Building No. 1050, Northwest corner of Doolittle Avenue & D Street; Harrison Township, Mount Clemens, Macomb County, MI

153

Land-use suitability analysis for urban development in Beijing.  

PubMed

Land-use suitability analyses are of considerable use in the planning of mega-cities. An Urban Development Land-use Suitability Mapping (UDLSM) approach has been constructed, based on opportunity and constraint criteria. Two Multi-criteria Evaluation (MCE) methods, the Ideal Point Method (IPM) and Ordered Weighted Averaging (OWA), were used to generate the opportunity map. The protection map was obtained by means of constraint criteria, utilizing the Boolean union operator. A suitability map was then generated by overlaying the opportunity and protection maps. By applying the UDLSM approach to Beijing, its urban development land-use suitability was mapped, and a sensitivity analysis undertaken to examine the robustness of the proposed approach. Indirect validation was achieved by mutual comparisons of suitability maps resulting from the two MCE methods, where the overall agreement of 91% and kappa coefficient of 0.78 indicated that both methods provide very similar spatial land-use suitability distributions. The suitability level decreases from central Beijing to its periphery, and the area classed as suitable amounts to 28% of the total area. Leading attributes of each opportunity factor for suitability were revealed, with 2256 km(2), i.e. 70%, of existing development land being overlaid by suitable areas in Beijing. Conflicting parcels of land were identified by overlaying the resultant map with two previous development blueprints for Beijing. The paper includes several recommendations aimed at improving the long-term urban development plans for Beijing. PMID:25036557

Liu, Renzhi; Zhang, Ke; Zhang, Zhijiao; Borthwick, Alistair G L

2014-12-01

154

Study on passive momentum exchange landing gear using two-dimensional analysis  

NASA Astrophysics Data System (ADS)

This paper discusses a landing response control system based on the momentum exchange principle for planetary exploration spacecraft. In the past, landing gear systems with cantilever designs that incorporate honeycomb materials to dissipate shock energy through plastic deformation have been used, but once tested before launch, the system cannot be used in a real mission. The sky crane system used for the Mars Science Laboratory by NASA can achieve a safe and precise landing, but it is highly complex. This paper introduces a momentum exchange impact damper (MEID) that absorbs the controlled object's momentum with extra masses called damper masses. The MEID is reusable, which makes it easy to ensure the landing gear's reliability. In this system, only passive elements such as springs are needed. A single-axis (SA) model has already been used to verify the effectiveness of MEIDs through simulations and experiments measuring the rebound height of the spacecraft. However, the SA model cannot address the rotational motion and tipping of the spacecraft. This paper presents a two-landing-gear-system (TLGS) model in which multiple MEIDs are equipped for two-dimensional analysis. Unlike in the authors' previous studies, in this study each MEID is launched when the corresponding landing gear lands and the MEIDs do not contain active actuators. This mechanism can be used to realize advanced control specifications, and it is simply compared with previous mechanisms including actuators, in which all of the MEIDs are launched simultaneously. If each MEID works when the corresponding gear lands, the rebound height of each gear can be minimized, and tipping can be prevented, as demonstrated by the results of our simulations.

Watanabe, Tsubasa; Hara, Susumu; Otsuki, Masatsugu

2014-12-01

155

Land use survey using remote sensing and geographical information systems  

Microsoft Academic Search

A hybrid system which integrates Remote Sensing (RS) data and Geographical Information Systems (GIS) information, has been developed for land use survey in Hiroshima city. The system consists of three interrelated subsystems, i.e., a personal computer, a minicomputer and an engineering workstation: The system can handle an image data base consisting of satellite digital images such as Landsat TM and

Yuzo Suga

1992-01-01

156

Environmental assessment and land change analysis in seminatural land covers applicable to land management  

NASA Astrophysics Data System (ADS)

The present research is based on the hypertemporal analysis of a set of 212 images from the NDVI index from January 2003 to March 2012 provided by the medium-resolution sensor MODIS TERRA. The study area is located in the center of the Iberian Peninsula (Spain). The specific objectives of the study are to investigate the rhythms of the annual development of the NDVI of each of the classes, determine the classes that are most sensitive to climatic variability and define the interannual sequences of variation in NDVI with an associated trend analysis. The classes situated in lower-altitude areas are strongly dependent on autumn rainfall and present negative temporal tendencies, and those situated at mountaintops and on upper slopes are correlated with spring-summer temperatures and exhibit stable or positive tendencies.

Bullón, Teresa

2015-02-01

157

14 CFR 23.729 - Landing gear extension and retraction system.  

Code of Federal Regulations, 2010 CFR

...1 2010-01-01 2010-01-01 false Landing gear extension and retraction system. 23.729...CATEGORY AIRPLANES Design and Construction Landing Gear § 23.729 Landing gear extension and retraction system. (a)...

2010-01-01

158

14 CFR 23.729 - Landing gear extension and retraction system.  

Code of Federal Regulations, 2011 CFR

...1 2011-01-01 2011-01-01 false Landing gear extension and retraction system. 23.729...CATEGORY AIRPLANES Design and Construction Landing Gear § 23.729 Landing gear extension and retraction system. (a)...

2011-01-01

159

A land surface soil moisture data assimilation system based on the dual-UKF method and the Community Land Model  

E-print Network

A land surface soil moisture data assimilation system based on the dual-UKF method and the Community Land Model Xiangjun Tian,1 Zhenghui Xie,1 and Aiguo Dai2 Received 28 November 2007; revised 10-UKF method to account for the effects of land surface subgrid- scale heterogeneity and soil water thawing

Dai, Aiguo

160

Automated Loads Analysis System (ATLAS)  

NASA Technical Reports Server (NTRS)

ATLAS is a generalized solution that can be used for launch vehicles. ATLAS is used to produce modal transient analysis and quasi-static analysis results (i.e., accelerations, displacements, and forces) for the payload math models on a specific Shuttle Transport System (STS) flight using the shuttle math model and associated forcing functions. This innovation solves the problem of coupling of payload math models into a shuttle math model. It performs a transient loads analysis simulating liftoff, landing, and all flight events between liftoff and landing. ATLAS utilizes efficient and numerically stable algorithms available in MSC/NASTRAN.

Gardner, Stephen; Frere, Scot; O’Reilly, Patrick

2013-01-01

161

Task Analysis of Shuttle Entry and Landing Activities  

NASA Technical Reports Server (NTRS)

The Task Analysis of Shuttle Entry and Landing (E/L) Activities documents all tasks required to land the Orbiter following an STS mission. In addition to analysis of tasks performed, task conditions are described, including estimated time for completion, altitude, relative velocity, normal and lateral acceleration, location of controls operated or monitored, and level of g's experienced. This analysis precedes further investigations into potential effects of zero g on piloting capabilities for landing the Orbiter following long-duration missions. This includes, but is not limited to, researching the effects of extended duration missions on piloting capabilities. Four primary constraints of the analysis must be clarified: (1) the analysis depicts E/L in a static manner--the actual process is dynamic; (2) the task analysis was limited to a paper analysis, since it was not feasible to conduct research in the actual setting (i.e., observing or filming duration an actual E/L); (3) the tasks included are those required for E/L during nominal, daylight conditions; and (4) certain E/L tasks will vary according to the flying style of each commander.

Holland, Albert W.; Vanderark, Stephen T.

1993-01-01

162

Automatic helical rotorcraft descent and landing using a Microwave Landing System  

NASA Technical Reports Server (NTRS)

A helical-approach concept is presented for Instrument Flight Rules (IFR) operation of rotorcraft into congested terminal areas where separation from high-speed jet traffic is highly desirable and the airport-precision-approach aid is a Microwave Landing System (MLS). The concept takes advantage of the fact that rotorcraft need not land on the main runway but can operate from a pad that lies on an MLS radial offset from the centerline. The results of 48 flights using a UH-1H helicopter and a research avionics system are presented. Three levels of navigation sophistication were also investigated. It is shown that an approach helix can be contained in a relatively small volume and that being within the Instrument Landing System (ILS) Category II window at a 30-m (100-ft) altitude is not a requirement for a successful hover over a landing pad. Only two of the three navigation systems provided estimates that allowed all flights to descend from hover to touchdown.

Mcgee, L. A.; Foster, J. D.; Xenakis, G.

1981-01-01

163

a Study of Urban Intensive Land Evaluating System  

NASA Astrophysics Data System (ADS)

The contradiction of land supply and demand is becoming increasingly prominent in China. The increasing efficiency of land use is an important means to resolve the conflict. We propose a scientific approach for promoting the urban intensive land use. In this paper, an evaluation system of urban intensive land use is programmed. It is designed to change the manual way of collecting index data and building index system to a dynamical way. The system improves the efficiency and accuracy of the evaluation of urban intensive land use. It achieves intensive evaluation on three scales: macro-level, medium-level and micro-level. We build two data extraction methods. One is XML-based meta-data exchange method that obtains index data from the cadastral database. Another is data monitoring method that writes the index data to the evaluation database at real time. Database technologies are used to calculate index values and build index systems dynamically. GIS technologies are use to achieve three scales evaluation of urban intensive land use.

Jiang, L.; Gu, J.; Chen, X.; You, Y.; Tang, Q.

2012-07-01

164

Ongoing Development of NASA's Global Land Data Assimilation System  

NASA Technical Reports Server (NTRS)

NASA's Global Land Data Assimilation System (GLDAS) produces global fields of land surface states (e.g., soil moisture and temperature) and fluxes (e.g., latent heat flux and runoff) by driving offline land surface models with observation-based inputs, using the Land Information System (LIS) software. Since production began in 2001, GLDAS has supported more than 100 scientific investigations and applications. Some examples are GEWEX and NASA Energy and Water Cycle Study (NEWS) global water and energy budget analyses, interpretations of hydrologic data derived from the Gravity Recovery and Climate Experiment (GRACE) satellite mission, and forecast model initiation studies at NOAA and NASA. At the same time, the GLDAS team has continued improve results through the development of new modeling and data assimilation techniques. Here we describe several recent and ongoing innovations. These include global implementation of a runoff routing procedure, GRACE data assimilation, advanced snow cover assimilation, and irrigation modeling.

Rodell, Matthew; Kato, Hiroko; Zaitchik, Ben

2008-01-01

165

An analysis of metropolitan land-use by machine processing of earth resources technology satellite data  

NASA Technical Reports Server (NTRS)

A successful application of state-of-the-art remote sensing technology in classifying an urban area into its broad land use classes is reported. This research proves that numerous urban features are amenable to classification using ERTS multispectral data automatically processed by computer. Furthermore, such automatic data processing (ADP) techniques permit areal analysis on an unprecedented scale with a minimum expenditure of time. Also, classification results obtained using ADP procedures are consistent, comparable, and replicable. The results of classification are compared with the proposed U. S. G. S. land use classification system in order to determine the level of classification that is feasible to obtain through ERTS analysis of metropolitan areas.

Mausel, P. W.; Todd, W. J.; Baumgardner, M. F.

1976-01-01

166

Validation of an Active Gear, Flexible Aircraft Take-off and Landing analysis (AGFATL)  

NASA Technical Reports Server (NTRS)

The results of an analytical investigation using a computer program for active gear, flexible aircraft take off and landing analysis (AGFATL) are compared with experimental data from shaker tests, drop tests, and simulated landing tests to validate the AGFATL computer program. Comparison of experimental and analytical responses for both passive and active gears indicates good agreement for shaker tests and drop tests. For the simulated landing tests, the passive and active gears were influenced by large strut binding friction forces. The inclusion of these undefined forces in the analytical simulations was difficult, and consequently only fair to good agreement was obtained. An assessment of the results from the investigation indicates that the AGFATL computer program is a valid tool for the study and initial design of series hydraulic active control landing gear systems.

Mcgehee, J. R.

1984-01-01

167

An analysis of landing rates and separations at the Dallas/Fort Worth International Airport  

NASA Technical Reports Server (NTRS)

Advanced air traffic management systems such as the Center/TRACON Automation System (CTAS) should yield a wide range of benefits, including reduced aircraft delays and controller workload. To determine the traffic-flow benefits achievable from future terminal airspace automation, live radar information was used to perform an analysis of current aircraft landing rates and separations at the Dallas/Fort Worth International Airport. Separation statistics that result when controllers balance complex control procedural constraints in order to maintain high landing rates are presented. In addition, the analysis estimates the potential for airport capacity improvements by determining the unused landing opportunities that occur during rush traffic periods. Results suggest a large potential for improving the accuracy and consistency of spacing between arrivals on final approach, and they support earlier simulation findings that improved air traffic management would increase capacity and reduce delays.

Ballin, Mark G.; Erzberger, Heinz

1996-01-01

168

Hierarchical resource analysis for land use planning through remote sensing  

NASA Technical Reports Server (NTRS)

A hierarchical resource analysis was applied to remote sensing data to provide maps at Planning Levels I and III (Anderson et al., U.S. Geological Survey Circular 671) for Meade County, S. Dak. Level I land use and general soil maps were prepared by visual interpretation of imagery from a false color composite of Landsat MSS bands 4, 5, and 7 and single bands (5 and 7). A modified Level III land use map was prepared for the Black Hills area from RB-57 photography enlarged to a scale of 1:24,000. Level III land use data were used together with computer-generated interpretive soil maps to analyze relationships between developed and developing areas and soil criteria.

Byrnes, B. H.; Frazee, C. J.; Cox, T. L.

1976-01-01

169

Global land cover mapping: a review and uncertainty analysis  

USGS Publications Warehouse

Given the advances in remotely sensed imagery and associated technologies, several global land cover maps have been produced in recent times including IGBP DISCover, UMD Land Cover, Global Land Cover 2000 and GlobCover 2009. However, the utility of these maps for specific applications has often been hampered due to considerable amounts of uncertainties and inconsistencies. A thorough review of these global land cover projects including evaluating the sources of error and uncertainty is prudent and enlightening. Therefore, this paper describes our work in which we compared, summarized and conducted an uncertainty analysis of the four global land cover mapping projects using an error budget approach. The results showed that the classification scheme and the validation methodology had the highest error contribution and implementation priority. A comparison of the classification schemes showed that there are many inconsistencies between the definitions of the map classes. This is especially true for the mixed type classes for which thresholds vary for the attributes/discriminators used in the classification process. Examination of these four global mapping projects provided quite a few important lessons for the future global mapping projects including the need for clear and uniform definitions of the classification scheme and an efficient, practical, and valid design of the accuracy assessment.

Congalton, Russell G.; Gu, Jianyu; Yadav, Kamini; Thenkabail, Prasad S.; Ozdogan, Mutlu

2014-01-01

170

Analysis of On-board Hazard Detection and Avoidance for Safe Lunar Landing  

NASA Technical Reports Server (NTRS)

Landing hazard detection and avoidance technology is being pursued within NASA to improve landing safety and increase access to sites of interest on the lunar surface. The performance of a hazard detection and avoidance system depends on properties of the terrain, sensor performance, algorithm design, vehicle characteristics and the overall all guidance navigation and control architecture. This paper analyzes the size of the region that must be imaged, sensor performance parameters and the impact of trajectory angle on hazard detection performance. The analysis shows that vehicle hazard tolerance is the driving parameter for hazard detection system design.

Johnson, Andrew E.; Huertas, Andres; Werner, Robert A.; Montgomery, James F.

2008-01-01

171

Visualization and Analysis of Multi-scale Land Surface Products via Giovanni Portals  

NASA Technical Reports Server (NTRS)

Large volumes of MODIS land data products at multiple spatial resolutions have been integrated into the Giovanni online analysis system to support studies on land cover and land use changes,focused on the Northern Eurasia and Monsoon Asia regions through the LCLUC program. Giovanni (Goddard Interactive Online Visualization ANd aNalysis Infrastructure) is a Web-based application developed by the NASA Goddard Earth Sciences Data and Information Services Center (GES DISC), providing a simple and intuitive way to visualize, analyze, and access Earth science remotely-sensed and modeled data.Customized Giovanni Web portals (Giovanni-NEESPI andGiovanni-MAIRS) have been created to integrate land, atmospheric,cryospheric, and societal products, enabling researchers to do quick exploration and basic analyses of land surface changes, and their relationships to climate, at global and regional scales. This presentation shows a sample Giovanni portal page, lists selected data products in the system, and illustrates potential analyses with imagesand time-series at global and regional scales, focusing on climatology and anomaly analysis. More information is available at the GES DISCMAIRS data support project portal: http:disc.sci.gsfc.nasa.govmairs.

Shen, Suhung; Kempler, Steven J.; Gerasimov, Irina V.

2013-01-01

172

Hyperspectral remote sensing data analysis for characterizing land surface conditions  

Microsoft Academic Search

The characterization of land surface conditions such as senescent plant materials, soils, green vegetation, and water bodies is essential information for understanding global change. The Airborne Visible\\/Infrared Imaging Spectrometer (AVIRIS) provides more detailed information about materials having specific narrow absorption features and possibilities for detecting very subtle variations than can be obtained from the broad bands of current sensors systems.

Chang-Woo Ahn

1996-01-01

173

Research priorities in land use and land-cover change for the Earth system and integrated assessment modelling  

SciTech Connect

This special issue has highlighted recent and innovative methods and results that integrate observations and AQ3 modelling analyses of regional to global aspect of biophysical and biogeochemical interactions of land-cover change with the climate system. Both the Earth System and the Integrated Assessment modeling communities recognize the importance of an accurate representation of land use and land-cover change to understand and quantify the interactions and feedbacks with the climate and socio-economic systems, respectively. To date, cooperation between these communities has been limited. Based on common interests, this work discusses research priorities in representing land use and land-cover change for improved collaboration across modelling, observing and measurement communities. Major research topics in land use and land-cover change are those that help us better understand (1) the interaction of land use and land cover with the climate system (e.g. carbon cycle feedbacks), (2) the provision of goods and ecosystem services by terrestrial (natural and anthropogenic) land-cover types (e.g. food production), (3) land use and management decisions and (4) opportunities and limitations for managing climate change (for both mitigation and adaptation strategies).

Hibbard, Kathleen A.; Janetos, Anthony C.; Van Vuuren, Detlef; Pongratz, Julia; Rose, Steven K.; Betts, Richard; Herold, Martin; Feddema, Johannes J.

2010-11-15

174

Assessing land-use change in Ireland using the Land-Parcel Identification System  

NASA Astrophysics Data System (ADS)

Carbon dynamics linked to Land-Use and Land-Use Change (LULUC) are considered a major factor in the global Greenhouse Gas (GHG) budget. The major sources of carbon to the atmosphere are the loss of above and below ground biomass as well as the loss of soil organic carbon. Estimates have shown that in the decade between 1990 and 2000 emissions related to LULUC and forestry have been between 0.5 and 2.7 Gt C yr-1. The major sources are conversion from forestry to agriculture and grasslands to cropland; conversely land-use change from cropland to grassland can facilitate soil carbon sequestration. While the effects of different types of land-use change on the GHG budget have been well studied, assessing land-use change at a national level is subject to uncertainty. In Ireland LULUC are currently modelled using national statistical data on total land-uses as well as socio-economic data. This may lead to inaccuracies as it neither provides information on direct land-use change trajectories nor spatially explicit information such as soil properties. The aim of this study is to assess the suitability of the land-parcel identification system (LPIS) to assess overall inter-annual land-use change as well as the immediate trajectory of change reported, and to provide tools for this purpose. For the available LPIS datasets (2000 to 2012) a number of issues have been identified. (1) Duplication of parcels led to a major overestimation of the agricultural area. On average 20917.7 ±7157.6 parcels showed one or multiple duplicates, leading to an overestimation of the agricultural area by 58194.2 ±11578.4km2, (2) no continuous identification of parcels through time complicates tracking land-use change, and (3) parcel outline changes over time without indication if the changes represent real-world changes or corrections of the LPIS database. Geoinformation Systems tools have been developed to address those issues, including a tool to remove duplicate parcels and a tool that assigns unique parcels identification codes based on spatial stability. To differentiate between real-world change and corrections in the database minimum criteria based on differences in parcel area (5% of the parcel area) and shifts in the parcel centroid over time (12m) have been introduced. Using the newly assigned parcel identification codes it could be shown that parcel stability between consecutive years is very high (on average 90.5% ±3.2 of the parcels in any year are present in the following year). When looking at the whole timeframe only 48.5% ±7.2 of the parcels recorded in 2000 are still present in 2012. These results indicate that LPIS has a strong potential for identifying inter-annual land-use change between consecutive years, however changes in parcel outlines lead to difficulties when comparing non-consecutive years. Further research will be conducted to adapt the available tools to estimate land-use change from changing parcels.

Zimmermann, Jesko; O'Brien, Phillip; Green, Stuart; Gonzales Del Campo, Ainhoa; Jones, Michael; Stout, Jane

2014-05-01

175

Mars Science Laboratory Entry, Descent, and Landing System Overview  

NASA Technical Reports Server (NTRS)

In 2010, the Mars Science Laboratory (MSL) mission will pioneer the next generation of robotic Entry, Descent, and Landing (EDL) systems by delivering the largest and most capable rover to date to the surface of Mars. In addition to landing more mass than prior missions to Mars, MSL will offer access to regions of Mars that have been previously unreachable. The MSL EDL sequence is a result of a more stringent requirement set than any of its predecessors. Notable among these requirements is landing a 900 kg rover in a landing ellipse much smaller than that of any previous Mars lander. In meeting these requirements, MSL is extending the limits of the EDL technologies qualified by the Mars Viking, Mars Pathfinder, and Mars Exploration Rover missions.

Prakash, Ravi; Burkhart, P. Dan; Chen, Allen; Comeaux, Keith A.; Guernsey, Carl S.; Devin, M. Kipp; Mendeck, Gavin F.; Powell, Richard W.; Rivellini, Tommaso P.; San Martin, A. Miguel; Sell, Steven W.; Steltzner, Adam D.; Way, David W.

2008-01-01

176

Land-Use Change Analysis Using GIS in the Water-Level-Fluctuating Zone of the Three Gorges Reservoir Region: A Kai'xian County Case  

Microsoft Academic Search

The water-level-fluctuating zone (WLFZ) in the Three Gorges Reservoir (TGR) changes seasonally because of the special hydrological characteristics and agriculture practices. Rapid land use changes have taken place in the WLFZ of the TGR, which is affected by the functions and structures of the local environmental system directly or indirectly. Land use change analysis is very important for land planning

Huang Chuan; Wang Li-ao; Yuan Hui; Bao Junjie

2010-01-01

177

Analysis of land cover change and its driving forces in a desert oasis landscape of southern Xinjiang, China  

NASA Astrophysics Data System (ADS)

The combined effects of drought, warming and the changes in land cover have caused severe land degradation for several decades in the extremely arid desert oases of Southern Xinjiang, Northwest China. This study examined land cover changes during 1990-2008 to characterize and quantify the transformations in the typical oasis of Hotan. Land cover classifications of these images were performed based on the supervised classification scheme integrated with conventional vegetation and soil indexes. Change-detection techniques in remote sensing (RS) and a geographic information system (GIS) were applied to quantify temporal and spatial dynamics of land cover changes. The overall accuracies, Kappa coefficients, and average annual increase rate or decrease rate of land cover classes were calculated to assess classification results and changing rate of land cover. The analysis revealed that major trends of the land cover changes were the notable growth of the oasis and the reduction of the desert-oasis ecotone, which led to accelerated soil salinization and plant deterioration within the oasis. These changes were mainly attributed to the intensified human activities. The results indicated that the newly created agricultural land along the margins of the Hotan oasis could result in more potential areas of land degradation. If no effective measures are taken against the deterioration of the oasis environment, soil erosion caused by land cover change may proceed. The trend of desert moving further inward and the shrinking of the ecotone may lead to potential risks to the eco-environment of the Hotan oasis over the next decades.

Amuti, T.; Luo, G.

2014-07-01

178

RITD - Adapting Mars Entry, Descent and Landing System for Earth  

NASA Astrophysics Data System (ADS)

Abstract A new generation of in?atable Entry, Descent and Landing System (EDLS) or Mars has been developed. It is used in both the initial atmospheric entry and atmospheric descent before the semi-hard impact of the penetrator into Martian surface. The EDLS applicability to Earth’s atmosphere is studied by the EU/RITD [1] project. Project focuses to the analysis and tests of the transonic behaviour of this compact and light weight payload entry system at the Earth re-entry 1. EDLS for Earth The dynamical stability of the craft is analysed, concentrating on the most critical part of the atmospheric re-entry, the transonic phase. In Martian atmosphere the MetNet vehicle stability during the transonic phase is understood. However, in the more dense Earth’s atmosphere, the transonic phase is shorter and turbulence more violent. Therefore, the EDLS has to be sufficiently dynamically stable to overcome the forces tending to deflect the craft from its nominal trajectory and attitude. The preliminary design of the inflatable EDLS for Earth will be commenced once the scaling of the re-entry system and the dynamical stability analysis have been performed. The RITD-project concentrates on mission and applications achievable with the current MetNet-type (i.e. “Mini-1” category) of lander, and on requirements posed by other type Earth re-entry concepts. 2. Entry Angle Determination for Mini-1 - lander For successful Earth landing, the suitable re-entry angle and velocity with specific descent vehicle (DV) mass and heat flux parameters need to be determined. These key parameters in determining the Earth re-entry for DV are: - qmax (kW/m2): maximal specific heat flux, - Q (MJ/m2): specific integral heat flux to DV front shield, - m (kg): descent vehicle (DV) mass, - V (m/s): re-entry velocity and - theta(deg.): flight-path angle at Earth re-entry For Earth re-entry, the calculation results in the optimal value of entry velocity for MetNet (“Mini-1” category) -type lander, with mass of 22kg, being VSOL = 5268 m/s. Using the basic pre-defined parameters for MetNet-type of lander in Earth atmosphere, we get the optimal angle of = -3.06 degrees for Earth re-entry. 3. Payload Mass for Earth Entry DV One of the key elements in Earth entry lander is the amount of available payload mass. The payload mass depends on, e.g., the lander size, landing type (soil or water), heat shield durability and additional landing gear. The payload mass will have an impact to the center of gravity of the lander. The payload with a “low” CoG (compared the the lander structure) has a larger tolerance than the payload with “high” CoG. In cases where payload CoG causes instability, the extra balance mass can be used to adjust CoG. This balance mass will reduce the available payload mass. A major limitation for payload mass is the heat shielding. Acknowledgements The research leading to these results has received funding from the European Community’s Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 263255. References [1] http://ritd.fmi.fi

Heilimo, Jyri; Aleksashkin, Sergey; Martynov, Maxim; Schmidt, Walter; Harri, Ari-Matti; Vsevolod Koryanov, D.; Kazakovtcev, Victor; Haukka, Harri; Arruego, Ignacio; Finchenko, Valery; Ostresko, Boris; Ponomarenko, Andrei; Martin, Susanna; Siili, Tero

179

RITD - Adapting Mars Entry, Descent and Landing System for Earth  

NASA Astrophysics Data System (ADS)

A new generation of inflatable Entry, Descent and Landing System (EDLS) for Mars has been developed. It is used in both the initial atmospheric entry and atmospheric descent before the semi-hard impact of the penetrator into Martian surface. The EDLS applicability to Earth's atmosphere is studied by the EU/RITD [1] project. Project focuses to the analysis and tests of the transonic behaviour of this compact and light weight payload entry system at the Earth re-entry. 1. EDLS for Earth The dynamical stability of the craft is analysed, concentrating on the most critical part of the atmospheric re-entry, the transonic phase. In Martian atmosphere the MetNet vehicle stability during the transonic phase is understood. However, in the more dense Earth's atmosphere, the transonic phase is shorter and turbulence more violent. Therefore, the EDLS has to be sufficiently dynamically stable to overcome the forces tending to deflect the craft from its nominal trajectory and attitude. The preliminary design of the inflatable EDLS for Earth will be commenced once the scaling of the re-entry system and the dynamical stability analysis have been performed. The RITD-project concentrates on mission and applications achievable with the current MetNet-type (i.e. 'Mini-1' category) of lander, and on requirements posed by other type Earth re-entry concepts. 2. Entry Angle Determination for Mini-1 - lander For successful Earth landing, the suitable re-entry angle and velocity with specific descent vehicle (DV) mass and heat flux parameters need to be determined. These key parameters in determining the Earth re-entry for DV are: qmax (kW/m2): maximal specific heat flux, Q (MJ/m2): specific integral heat flux to DV front shield, m (kg): descent vehicle (DV) mass, V (m/s): re-entry velocity and ? (deg.): flight-path angle at Earth re-entry For Earth re-entry, the calculation results in the optimal value of entry velocity for MetNet ('Mini-1' category) -type lander, with mass of 22kg, being VSOL = 5268 m/s. Using the basic pre-defined parameters for MetNet-type of lander in Earth atmosphere, we get the optimal angle of ? = -3.06 degrees for Earth re-entry. 3. Payload Mass for Earth Entry DV One of the key elements in Earth entry lander is the amount of available payload mass. The payload mass depends on, e.g., the lander size, landing type (soil or water), heat shield durability and additional landing gear. The payload mass will have an impact to the center of gravity of the lander. The payload with a 'low' CoG (compared the the lander structure) has a larger tolerance than the payload with 'high' CoG. In cases where payload CoG causes instability, the extra balance mass can be used to adjust CoG. This balance mass will reduce the available payload mass. A major limitation for payload mass is the heat shielding. Acknowledgements The research leading to these results has received funding from the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 263255. References [1] http://ritd.fmi.fi

Heilimo, Jyri; Harri, Ari-Matti; Aleksashkin, Sergey; Koryanov, Vsevolod; Arruego, Ignacio; Schmidt, Walter; Haukka, Harri; Finchenko, Valery; Martynov, Maxim; Ostresko, Boris; Ponomarenko, Andrey; Kazakovtsev, Viktor; Martin, Susanna; Siili, Tero

2014-05-01

180

A Stochastic Model for the Landing Dispersion of Hazard Detection and Avoidance Capable Flight Systems  

NASA Astrophysics Data System (ADS)

To support landing site assessments for HDA-capable flight systems and to facilitate trade studies between the potential HDA architectures versus the yielded probability of safe landing a stochastic landing dispersion model has been developed.

Witte, L.

2014-06-01

181

Helical automatic approaches of helicopters with microwave landing systems  

NASA Technical Reports Server (NTRS)

A program is under way to develop a data base for establishing navigation and guidance concepts for all-weather operation of rotorcraft. One of the objectives is to examine the feasibility of conducting simultaneous rotorcraft and conventional fixed-wing, noninterfering, landing operations in instrument meteorological conditions at airports equipped with microwave landing systems (MLSs) for fixed-wing traffic. An initial test program to investigate the feasibility of conducting automatic helical approaches was completed, using the MLS at Crows Landing near Ames. These tests were flown on board a UH-1H helicopter equipped with a digital automatic landing system. A total of 48 automatic approaches and landings were flown along a two-turn helical descent, tangent to the centerline of the MLS-equipped runway to determine helical light performance and to provide a data base for comparison with future flights for which the helical approach path will be located near the edge of the MLS coverage. In addition, 13 straight-in approaches were conducted. The performance with varying levels of state-estimation system sophistication was evaluated as part of the flight tests. The results indicate that helical approaches to MLS-equipped runways are feasible for rotorcraft and that the best position accuracy was obtained using the Kalman-filter state-estimation with inertial navigation systems sensors.

Foster, J. D.; Mcgee, L. A.; Dugan, D. C.

1982-01-01

182

US aircraft landing systems-VHF-UHF and microwave  

Microsoft Academic Search

The aircraft instrument landing system (ILS), operating in the VHF\\/UHF frequency bands has been in operation for over 50 years. With the various glide slope systems and the highly directional localizer antenna arrays successful ILS performance can now be achieved under the most adverse electromagnetic conditions. Several disadvantages prevent ILS from meeting the needs of aviation indefinitely. These disadvantages are

H. W. Cooper

1990-01-01

183

Systemic change increases forecast uncertainty of land use change models  

NASA Astrophysics Data System (ADS)

Cellular Automaton (CA) models of land use change are based on the assumption that the relationship between land use change and its explanatory processes is stationary. This means that model structure and parameterization are usually kept constant over time, ignoring potential systemic changes in this relationship resulting from societal changes, thereby overlooking a source of uncertainty. Evaluation of the stationarity of the relationship between land use and a set of spatial attributes has been done by others (e.g., Bakker and Veldkamp, 2012). These studies, however, use logistic regression, separate from the land use change model. Therefore, they do not gain information on how to implement the spatial attributes into the model. In addition, they often compare observations for only two points in time and do not check whether the change is statistically significant. To overcome these restrictions, we assimilate a time series of observations of real land use into a land use change CA (Verstegen et al., 2012), using a Bayesian data assimilation technique, the particle filter. The particle filter was used to update the prior knowledge about the parameterization and model structure, i.e. the selection and relative importance of the drivers of location of land use change. In a case study of sugar cane expansion in Brazil, optimal model structure and parameterization were determined for each point in time for which observations were available (all years from 2004 to 2012). A systemic change, i.e. a statistically significant deviation in model structure, was detected for the period 2006 to 2008. In this period the influence on the location of sugar cane expansion of the driver sugar cane in the neighborhood doubled, while the influence of slope and potential yield decreased by 75% and 25% respectively. Allowing these systemic changes to occur in our CA in the future (up to 2022) resulted in an increase in model forecast uncertainty by a factor two compared to the assumption of a stationary system. This means that the assumption of a constant model structure is not adequate and largely underestimates uncertainty in the forecast. Non-stationarity in land use change projections is challenging to model, because it is difficult to determine when the system will change and how. We believe that, in sight of these findings, land use change modelers should be more aware, and communicate more clearly, that what they try to project is at the limits, and perhaps beyond the limits, of what is still projectable. References Bakker, M., Veldkamp, A., 2012. Changing relationships between land use and environmental characteristics and their consequences for spatially explicit land-use change prediction. Journal of Land Use Science 7, 407-424. Verstegen, J.A., Karssenberg, D., van der Hilst, F., Faaij, A.P.C., 2012. Spatio-Temporal Uncertainty in Spatial Decision Support Systems: a Case Study of Changing Land Availability for Bioenergy Crops in Mozambique. Computers , Environment and Urban Systems 36, 30-42.

Verstegen, J. A.; Karssenberg, D.; van der Hilst, F.; Faaij, A.

2013-12-01

184

Air cushion landing system stability study  

NASA Astrophysics Data System (ADS)

An analysis of an inelastic ACLS plunge mode dynamic model is presented. The ACLS has unrestrained side elements and frozen end elements. The model exhibits unstable behavior at certain operating conditions for which the side elements are in contact with the ground. A linear analysis showed this instability to be due mainly to the altitude sensitivities of the cushion to atmosphere airflows and the attendant influence on the dynamic pressure forces on the vehicle. The model instability can be alleviated by isolating side and end elements so that they are all unrestrained and by simultaneously venting the air cushion directly to atmosphere.

Burton, T. D.

1981-02-01

185

Commercialization of the land remote sensing system: An examination of mechanisms and issues  

NASA Technical Reports Server (NTRS)

In September 1982 the Secretary of Commerce was authorized (by Title II of H.R. 5890 of the 97th Congress) to plan and provide for the management and operation of the civil land remote sensing satellite systems, to provide for user fees, and to plan for the transfer of the ownership and operation of future civil operational land remote sensing satellite systems to the private sector. As part of the planning for transfer, a number of approaches were to be compared including wholly private ownership and operation of the system by an entity competitively selected, mixed government/private ownership and operation, and a legislatively-chartered privately-owned corporation. The results of an analysis and comparison of a limited number of financial and organizational approaches for either transfer of the ownership and operation of the civil operational land remote sensing program to the private sector or government retention are presented.

Cauley, J. K.; Gaelick, C.; Greenberg, J. S.; Logsdon, J.; Monk, T.

1983-01-01

186

Implementation and Application of the Kalman Filter Data Assimilation Approaches in NASA's Land Information System Infrastructure  

Microsoft Academic Search

Building on the North-American and Global Land Data Assimilation Systems (LDAS), a Land Information System (LIS) infrastructure has been developed at NASA Goddard Space Flight Center jointly with NOAA- NCEP, NWS and university collaborators. In the context of numerical weather prediction applications, LDAS can provide optimal estimates of land surface state initial conditions by integrating with an ensemble of land

X. Zhan; S. Kumar; W. T. Crow; K. Arsenault; P. R. Houser; C. Peters-Lidard

2006-01-01

187

Rapid prototyping of soil moisture estimates using the NASA Land Information System  

Microsoft Academic Search

The Land Information System (LIS), developed at the NASA Goddard Space Flight Center, is a functional Land Data Assimilation System (LDAS) that incorporates a suite of land models in an interoperable computational framework. LIS has been integrated into a computational Rapid Prototyping Capabilities (RPC) infrastructure. LIS consists of a core, a number of community land models, data servers, and visualization

V. Anantharaj; G. Mostovoy; B. Li; C. Peters-Lidard; P. Houser; R. Moorhead; S. Kumar

2007-01-01

188

Multipath effect suppression for instrument landing system based on MUSIC  

Microsoft Academic Search

The Decimeter-wavelength Instrument Landing System is designed to assure an exact and timely flight arrival on many airports. But its signal can often be distorted by reflections and scattering caused by objects which are illuminated by the radiating antennas, sometimes referred to be \\

Xiubin Zhao; Yongsheng Wang; Hengle Jiang; Chuanjin Dai

2005-01-01

189

Microprocessor-Controlled Communications in an Advanced Instrument Landing System  

Microsoft Academic Search

The application of 4-bit microprocessors to the communication of the control and status signals found in an advanced aircraft instrument landing system is presented. The advantages as well as some of the peculiarities of such an approach are described. Among the benefits, one must include the possibility of a very convenient and understandable human interface.

S. E. Belter; C. R. Williams; S. C. Bass

1976-01-01

190

Applications of slotted cable antennas in the instrument landing system  

Microsoft Academic Search

The use of slotted waveguides in the instrument landing system (ILS) is discussed, and applications of slotted cable antennas to the ILS localizer and glide slope are described. Examples are given of both existing and prospective designs intended to provide solutions for specific siting problems. Important applications are to the end-fire glide slope and category-III localizers

1990-01-01

191

The Instrument Landing System: Replace it, or Repair it?  

Microsoft Academic Search

The Instrument Landing System (ILS), in its present 90\\/150 Hz format, had its beginnings in the United States and England during the years 1939 to 1945. Since then, it has served the aviation community worldwide. There have been many improvements to cope with ever increasing traffic, crowded airports, and difficult siting problems. There are those who say that it's time

Chester B. Watts

1999-01-01

192

Elimination of background clutter in airports for instrument landing systems  

Microsoft Academic Search

Specular reflection from airport buildings interferes with instrument landing systems. It is possible to eliminate these specular reflections by periodic strip grating techniques. These metallic strips, when painted over a dielectric sheet, are found to eliminate the specular reflections from a plane metallic surface and the surface behaves as a `non reflecting conducting surface.' These inexpensive surfaces are lightweight and

K. A. Jose; Vijay K. Varadan; Vasundara V. Varadan

1994-01-01

193

A Look at the Future of Automatic Landing Systems  

Microsoft Academic Search

Current systems of instrument approach guidance, even with recent and forthcoming improvements, are shown to be inadequate for future operational needs. The potential weaknesses of current techniques include restrictions on flight-control maneuverability, limited landing rates, special terrain and siting requirements, and deterioration of service in the critical low-altitude region near touchdown. A broad look at future requirements, especially those posed

G. B. Litchford; A. Tatz; F. H. Battle

1959-01-01

194

Orion Landing and Recovery Systems Development - Government Contributions  

NASA Technical Reports Server (NTRS)

This slide presentation reviews NASA's work in development of landing and recovery systems for the Orion space craft. It includes a review of the available tools and skills that assist in analyzing the aerodynamic decelerators. There is a description of the work that is being done on the Government Furnished Equipment (GFE) parachutes that will be used with the Orion Crew Exploration Vehicle (CEV)

Machin, Ricardo A.

2010-01-01

195

Low cost airborne microwave landing system receiver, task 3  

NASA Technical Reports Server (NTRS)

Work performed on the low cost airborne Microwave Landing System (MLS) receiver is summarized. A detailed description of the prototype low cost MLS receiver is presented. This detail includes block diagrams, schematics, board assembly drawings, photographs of subassemblies, mechanical construction, parts lists, and microprocessor software. Test procedures are described and results are presented.

Hager, J. B.; Vancleave, J. R.

1979-01-01

196

Solar System: Stranded in no-man's-land  

NASA Astrophysics Data System (ADS)

The discovery of a second resident in a region of the Solar System called the inner Oort cloud prompts fresh thinking about this no-man's-land between the giant planets and the reservoir of comets of long orbital period. See Letter p.471

Schwamb, Megan E.

2014-03-01

197

Selecting landing sites for lunar lander missions using spatial analysis  

NASA Astrophysics Data System (ADS)

Russian Federal Space Agency (Roscosmos) is planning to launch two spacecrafts to the Moon with lander missions in 2015 and 2017. [1] Here, we present an approach to create a method of landing sites selection. We researched the physical features of the Moon using spatial analysis techniques presented in ArcGIS Desktop Software in accordance with its suitability for automatic landing. Hence we analyzed Russian lunar program and received the technical characteristics of the spacecrafts and scientific goals that they should meet [1]. Thus we identified the criteria of surface suitability for landing. We divided them into two groups: scientific criteria (the hydrogen content of the regolith [2] and day and night sur-face temperature [3]) and safety criteria (surface slopes and roughness, sky view factor, the Earth altitude, presence of polar permanently shadowed regions). In conformity with some investigations it is believed that the south polar region of the Moon is the most promising territory where water ice can be found (finding water ice is the main goal for Russian lunar missions [1]). According to the selected criteria and selected area of research we used remote sensing data from LRO (Lunar Reconnaissance Orbiter) [4] as basic data, because it is the most actual and easily available. The data was processed and analyzed using spatial analysis techniques of ArcGIS Desktop Software, so we created a number of maps depicting the criteria and then combined and overlaid them. As a result of overlay process we received five territories where the landing will be safe and the scientific goals will have being met. It should be noted that our analysis is only the first order assessment and the results cannot be used as actual landing sites for the lunar missions in 2015 and 2017, since a number of factors, which can only be analyzed in a very large scale, was not taken into account. However, an area of researching is narrowed to five territories, what can make the future research much easier. The analysis of these five areas in a large scale will be the subject of further research. References: [1] Mitrofanov I. G. et al. (2011) LPS XLII, Abstract #1798 [2] Mitrofanov I. G., et al. Hydrogen Mapping of the Lunar South Pole Using the LRO Neutron Detector Experiment LEND // Science vol. 330 2010, pp. 483-486 [3] Paige D.A. et al. (2011) LPS XLII, Abstract #2544 [4] Zuber M.T. et al. (2010) Space Sci. Rev., 150, 63-80

Djachkova, Maia; Lazarev, Evgeniy

198

Developing a Prototype ALHAT Human System Interface for Landing  

NASA Technical Reports Server (NTRS)

The goal of the Autonomous Landing and Hazard Avoidance Technology (ALHAT) project is to safely execute a precision landing anytime/anywhere on the moon. This means the system must operate in any lighting conditions, operate in the presence of any thruster generated regolith clouds, and operate without the help of redeployed navigational aids or prepared landing site at the landing site. In order to reach this ambitious goal, computer aided technologies such as ALHAT will be needed in order to permit these landings to be done safely. Although there will be advanced autonomous capabilities onboard future landers, humans will still be involved (either onboard as astronauts or remotely from mission control) in any mission to the moon or other planetary body. Because many time critical decisions must be made quickly and effectively during the landing sequence, the Descent and Landing displays need to be designed to be as effective as possible at presenting the pertinent information to the operator, and allow the operators decisions to be implemented as quickly as possible. The ALHAT project has established the Human System Interface (HSI) team to lead in the development of these displays and to study the best way to provide operators enhanced situational awareness during landing activities. These displays are prototypes that were developed based on multiple design and feedback sessions with the astronaut office at NASA/ Johnson Space Center. By working with the astronauts in a series of plan/build/evaluate cycles, the HSI team has obtained astronaut feedback from the very beginning of the design process. In addition to developing prototype displays, the HSI team has also worked to provide realistic lunar terrain (and shading) to simulate a "out the window" view that can be adjusted to various lighting conditions (based on a desired date/time) to allow the same terrain to be viewed under varying lighting terrain. This capability will be critical to determining the effect of terrain/lighting on the human pilot, and how they use windows and displays during landing activities. The Apollo missions were limited to about 28 possible launch days a year due to lighting and orbital constraints. In order to take advantage of more landing opportunities and venture to more challenging landing locations, future landers will need to utilize sensors besides human eyes for scanning the surface. The ALHAT HSI system must effectively convey ALHAT produced information to the operator, so that landings can occur during less "optimal" conditions (lighting, surface terrain, slopes, etc) than was possible during Apollo missions. By proving this capability, ALHAT will simultaneously provide more flexible access to the moon, and greater safety margins for future landers. This paper will specifically focus on the development of prototype displays (the Trajectory Profile Display (TPD), Landing Point Designation (LPD), and Crew Camera View (CCV) ), implementation of realistic planetary terrain, human modeling, and future HSI plans.

Hirsh, Robert L.; Chua, Zarrin K.; Heino, Todd A.; Strahan, Al; Major, Laura; Duda, Kevin

2011-01-01

199

Lunar Navigation Determination System - LaNDS  

NASA Technical Reports Server (NTRS)

A portable comprehensive navigational system has been developed that both robotic and human explorers can use to determine their location, attitude, and heading anywhere on the lunar surface independent of external infrastructure (needs no Lunar satellite network, line of sight to the Sun or Earth, etc.). The system combines robust processing power with an extensive topographical database to create a real-time atlas (GIS Geospatial Information System) that is able to autonomously control and monitor both single unmanned rovers and fleets of rovers, as well as science payload stations. The system includes provisions for teleoperation and tele-presence. The system accepts (but does not require) inputs from a wide range of sensors. A means was needed to establish a location when the search is taken deep in a crater (looking for water ice) and out of view of Earth or any other references. A star camera can be employed to determine the user's attitude in menial space and stellar map in body space. A local nadir reference (e.g., an accelerometer that orients the nadir vector in body space) can be used in conjunction with a digital ephemeris and gravity model of the Moon to isolate the latitude, longitude, and azimuth of the user on the surface. That information can be used in conjunction with a Lunar GIS and advanced navigation planning algorithms to aid astronauts (or other assets) to navigate on the Lunar surface.

Quinn, David; Talabac, Stephen

2012-01-01

200

Photogrammetric Measurements of CEV Airbag Landing Attenuation Systems  

NASA Technical Reports Server (NTRS)

High-speed photogrammetric measurements are being used to assess the impact dynamics of the Orion Crew Exploration Vehicle (CEV) for ground landing contingency upon return to earth. Test articles representative of the Orion capsule are dropped at the NASA Langley Landing and Impact Research (LandIR) Facility onto a sand/clay mixture representative of a dry lakebed from elevations as high as 62 feet (18.9 meters). Two different types of test articles have been evaluated: (1) half-scale metal shell models utilized to establish baseline impact dynamics and soil characterization, and (2) geometric full-scale drop models with shock-absorbing airbags which are being evaluated for their ability to cushion the impact of the Orion CEV with the earth s surface. This paper describes the application of the photogrammetric measurement technique and provides drop model trajectory and impact data that indicate the performance of the photogrammetric measurement system.

Barrows, Danny A.; Burner, Alpheus W.; Berry, Felecia C.; Dismond, Harriett R.; Cate, Kenneth H.

2008-01-01

201

MOLDOVA LAND TENURE SYSTEM Carlton A Brown  

E-print Network

1990s, the United States Agency for International Development (USAID) instituted a cadastral system constitution on September 29, 1994. According to the constitution, Moldova is a democratic state in which back to 1360 A.D. The peak of this medieval Moldovan state was during the rule of Stefan the Great

Onsrud, Harlan J.

202

Modeling and Simulation of the Second-Generation Orion Crew Module Air Bag Landing System  

NASA Technical Reports Server (NTRS)

Air bags were evaluated as the landing attenuation system for earth landing of the Orion Crew Module (CM). An important element of the air bag system design process is proper modeling of the proposed configuration to determine if the resulting performance meets requirements. Analysis conducted to date shows that airbags are capable of providing a graceful landing of the CM in nominal and off-nominal conditions such as parachute failure, high horizontal winds, and unfavorable vehicle/ground angle combinations. The efforts presented here surround a second generation of the airbag design developed by ILC Dover, and is based on previous design, analysis, and testing efforts. In order to fully evaluate the second generation air bag design and correlate the dynamic simulations, a series of drop tests were carried out at NASA Langley's Landing and Impact Research (LandIR) facility. The tests consisted of a full-scale set of air bags attached to a full-scale test article representing the Orion Crew Module. The techniques used to collect experimental data, construct the simulations, and make comparisons to experimental data are discussed.

Timmers, Richard B.; Welch, Joseph V.; Hardy, Robin C.

2009-01-01

203

Intersects between Land, Energy, Water and the Climate System  

NASA Astrophysics Data System (ADS)

Climate change affects water, and land resources, and with growing human activity, each of these sectors relies increasingly on the others for critical resources. Events such as drought across the South Central U.S. during 2011 demonstrate that climatic impacts within each of these sectors can cascade through interactions between sectors. Energy, water, and land resources are each vulnerable to impacts on either of the other two sectors. For example, energy systems inherently require land and water. Increased electricity demands to contend with climate change can impose additional burdens on overly subscribed water resources. Within this environment, energy systems compete for water with agriculture, human consumption, and other needs. In turn, climate driven changes in landscape attributes and land use affect water quality and availability as well as energy demands. Diminishing water quality and availability impose additional demands for energy to access and purify water, and for land to store and distribute water. In some situations, interactions between water, energy, and land resources make options for reducing greenhouse gas emissions vulnerable to climate change. Energy options such as solar power or biofuel use can reduce net greenhouse gas emissions as well as U.S. dependence on foreign resources. As a result, the U.S. is expanding renewable energy systems. Advanced technology such as carbon dioxide capture with biofuels may offer a means of removing CO2 from the atmosphere. But as with fossil fuels, renewable energy sources can impose significant demands for water and land. For example, solar power mayrequire significant land to site facilities and water for cooling or to produce steam. Raising crops to produce biofuels uses arable land and water that might otherwise be available for food production. Thus, warmer and drier climate can compromise these renewable energy resources, and drought can stress water supplies creating competition between energy production and agriculture. These kinds of stresses often initiate innovated technological developments, such as dry cooling to reduce water demands in the U.S. Southwest for utility-scalesolar development, however, the need for large areas of land remain, and often, large land tracts in this region are under Federal ownership and used as conservation or wildlife refuges. Conflicting stakeholder views, institutional commitments, and international concerns can constrain options for reducing vulnerability to climate change, and interactions among water, energy, and land resource sectors can intensify such constraints. While management decisions may focus primarily on one of these resource sectors, where the three sectors are tightly coupled, options for mitigating or adapting to climate change may be limited more than expected. For example, the Columbia River Treaty between Canada and the U.S. emphasizes hydroelectric power and flood control, but with warmer temperatures and drier summers projected for the Northwest, diminishing water supplies will result in increased pumping for resource production (i.e., deeper groundwater) and transmission. Finally, coordinated water management for agriculture, ecosystem services, and hydropower will be an important aspect of adaptation not necessarily accommodated by the Treaty.

Hibbard, K. A.; Skaggs, R.; Wilson, T.

2012-12-01

204

Load-limiting landing gear footpad energy absorption system  

NASA Technical Reports Server (NTRS)

As a precursor to future manned missions to the moon, an inexpensive, unmanned vehicle that could carry small, scientific payloads to the lunar surface was studied by NASA. The vehicle, called the Common Lunar Lander, required extremely optimized structural systems to increase the potential payload mass. A lightweight energy-absorbing system (LAGFEAS), which also acts as a landing load-limiter was designed to help achieve this optimized structure. Since the versatile and easily tailored system is a load-limiter, it allowed for the structure to be designed independently of the ever-changing landing energy predictions. This paper describes the LAGFEAS system and preliminary verification testing performed at NASA's Johnson Space Center for the Common Lunar Lander program.

Hansen, Chris; Tsai, Ted

1994-01-01

205

Descriptive land Impact asses.  

E-print Network

Descriptive land use model Impact asses. Impact asses. Impact asses. Impact asses. Conflicts and regulations Functioning of sub-systems Revised goals and objectives "Networks in the Delta" Land use analysis for interactive integrated physical planning Study area Land use change modelling "Networks in the Delta" Faculty

Schot, Paul

206

VITS-A Vision System for Autonomous Land Vehicle Navigation  

Microsoft Academic Search

A description is given of VITS (for vision task sequencer), the vision system for the autonomous land vehicle (ALV) Alvin, addressing in particular the task of road-following. The ALV vision system builds symbolic descriptions of road and obstacle boundaries using both video and range sensors. The authors discuss various road segmentation methods for video-based road-following, along with approaches to boundary

MATTHEW A. TURK; David G. Morgenthaler; Keith D. Gremban; Martin Marra

1988-01-01

207

Automated, on-board terrain analysis for precision landings  

NASA Technical Reports Server (NTRS)

Advances in space robotics technology hinge to a large extent upon the development and deployment of sophisticated new vision-based methods for automated in-space mission operations and scientific survey. To this end, we have developed a new concept for automated terrain analysis that is based upon a generic image enhancement platform|multi-scale retinex (MSR) and visual servo (VS) processing. This pre-conditioning with the MSR and the vs produces a "canonical" visual representation that is largely independent of lighting variations, and exposure errors. Enhanced imagery is then processed with a biologically inspired two-channel edge detection process, followed by a smoothness based criteria for image segmentation. Landing sites can be automatically determined by examining the results of the smoothness-based segmentation which shows those areas in the image that surpass a minimum degree of smoothness. Though the msr has proven to be a very strong enhancement engine, the other elements of the approach|the vs, terrain map generation, and smoothness-based segmentation|are in early stages of development. Experimental results on data from the Mars Global Surveyor show that the imagery can be processed to automatically obtain smooth landing sites. In this paper, we describe the method used to obtain these landing sites, and also examine the smoothness criteria in terms of the imager and scene characteristics. Several examples of applying this method to simulated and real imagery are shown.

Rahman, Zia-ur; Jobson, Daniel J.; Woodell, Glenn A.; Hines, Glenn D.

2006-01-01

208

Automated On-board Terrain Analysis for Precision Landings  

NASA Technical Reports Server (NTRS)

Advances in space robotics technology hinge to a large extent upon the development and deployment of sophisticated new vision-based methods for automated in-space mission operations and scientific survey. To this end, we have developed a new concept for automated terrain analysis that is based upon a generic image enhancement platform-multi-scale Retinex (MSR) and visual servo (VS) processing. This pre-conditioning with the MSR and the VS produces a "canonical" visual representation that is largely independent of lighting variations, and exposure errors. Enhanced imagery is then processed with a biologically inspired two-channel edge detection process, followed by a smoothness based criteria for image segmentation. Landing sites can be automatically determined by examining the results of the smoothness-based segmentation which shows those areas in the image that surpass a minimum degree of smoothness. Though the MSR has proven to be a very strong enhancement engine, the other elements of the approach, the VS, terrain map generation, and smoothness-based segmentation, are in early stages of development. Experimental results on data from the Mars Global Surveyor show that the imagery can be processed to automatically obtain smooth landing sites. In this paper, we describe the method used to obtain these landing sites, and also examine the smoothness criteria in terms of the imager and scene characteristics. Several examples of applying this method to simulated and real imagery are shown.

Rahman, Zia-ur; Jobson, Daniel J.; Woodell, Glenn A.; Hines, Glenn D.

2006-01-01

209

Land-mobile satellite communication system  

NASA Technical Reports Server (NTRS)

A satellite communications system includes an orbiting communications satellite for relaying communications to and from a plurality of ground stations, and a network management center for making connections via the satellite between the ground stations in response to connection requests received via the satellite from the ground stations, the network management center being configured to provide both open-end service and closed-end service. The network management center of one embodiment is configured to provides both types of service according to a predefined channel access protocol that enables the ground stations to request the type of service desired. The channel access protocol may be configured to adaptively allocate channels to open-end service and closed-end service according to changes in the traffic pattern and include a free-access tree algorithm that coordinates collision resolution among the ground stations.

Yan, Tsun-Yee (Inventor); Rafferty, William (Inventor); Dessouky, Khaled I. (Inventor); Wang, Charles C. (Inventor); Cheng, Unjeng (Inventor)

1993-01-01

210

77 FR 2563 - Public Land Order No. 7787; Withdrawal of Public and National Forest System Lands in the Grand...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Forest System Lands in the Grand Canyon Watershed; Arizona AGENCY: Bureau of Land Management...in order to protect the Grand Canyon Watershed from adverse effects of locatable mineral...in order to protect the Grand Canyon Watershed from adverse effects of locatable...

2012-01-18

211

Study of USGS/NASA land use classification system. [compatibility of land use classification system with computer processing techniques employed for land use mapping from ERTS data  

NASA Technical Reports Server (NTRS)

It is known from several previous investigations that many categories of land-use can be mapped via computer processing of Earth Resources Technology Satellite data. The results are presented of one such experiment using the USGS/NASA land-use classification system. Douglas County, Georgia, was chosen as the test site for this project. It was chosen primarily because of its recent rapid growth and future growth potential. Results of the investigation indicate an overall land-use mapping accuracy of 67% with higher accuracies in rural areas and lower accuracies in urban areas. It is estimated, however, that 95% of the State of Georgia could be mapped by these techniques with an accuracy of 80% to 90%.

Spann, G. W.; Faust, N. L.

1974-01-01

212

Testing of CMA-2000 Microwave Landing System (MLS) airborne receiver  

NASA Astrophysics Data System (ADS)

Microwave landing system (MLS) is a precision approach and landing guidance system which provides position information and various air to ground data. Position information is provided on a wide coverage sector and is determined by an azimuth angle measurement, an elevation angle measurement, and a range measurement. MLS performance standards and testing of the MLS airborne receiver is mainly governed by Technical Standard Order TSO-C104 issued by the Federal Aviation Administration. This TSO defines detailed test procedures for use in determining the required performance under standard and stressed conditions. It also imposes disciplines on software development and testing procedures. Testing performed on the CMA-2000 MLS receiver and methods used in its validation are described. A computer automated test system has been developed to test for compliance with RTCA/DO-177 Minimum Operation Performance Standards. Extensive software verification and traceability tests designed to ensure compliance with RTCA/DO-178 are outlined.

Labreche, L.; Murfin, A. J.

1989-09-01

213

Propeller modulation effects on a scanning beam microwave landing system  

NASA Technical Reports Server (NTRS)

An investigation to assess the modulation effects on microwave signals transmitted through rotating propeller blades. Interruption of the antenna line-of-sight signal by the rotating propeller causes a variation of path loss, which produces essentially an amplitude modulation of the received signal. This interruption or blockage effect is generally only partial because of edge diffraction around the particular interfering propeller blade. Signals reflected from the rotating propeller will also cause Doppler frequency shifts to be present in the received signals. A scanning beam microwave landing system (MLS) known as MODILS (modular instrument landing system) was used to process the received signals for display. The effects of propeller modulation were studied by varying the following parameters: (1) spacing between propeller and receiving antenna, (2) propeller dimensions, (3) propeller speed (rpm), (4) number of propeller blades, (5) system data rate, (6) receiver response time, and (7) receiver antenna aperture.

Pope, J. M.; Staehle, W. H.

1974-01-01

214

Multipath effect suppression for instrument landing system based on MUSIC  

NASA Astrophysics Data System (ADS)

The Decimeter-wavelength Instrument Landing System is designed to assure an exact and timely flight arrival on many airports. But its signal can often be distorted by reflections and scattering caused by objects which are illuminated by the radiating antennas, sometimes referred to be "multipath", which pose a great threat to the system's operation. In this paper, an improved receiver based on spatial spectrum estimation concepts is proposed for safer automatic landing procedures. The new approach is based on Direction of Arrival (DOA) estimation performed by the MUSIC algorithm and signal filter performed by beamforming algorithm. The superior performance of the proposed system with respect to currently employed techniques in the presence of unwanted interferences has been tested in extensive computer simulations.

Zhao, Xiubin; Wang, Yongsheng; Jiang, Hengle; Dai, Chuanjin

2005-11-01

215

Digital simulation of continuous error models with application to an instrument landing system error  

NASA Technical Reports Server (NTRS)

A digital simulation of the continuous error of the localized beam of a conventional instrument landing system is discussed. The digital simulation was developed during the analysis of space shuttle navigation capabilities. A discrete mathematical model for use on a digital computer is described. The model generates an output random sequence which is equivalent, for simulation purposes, to the desired random process. The model is a system of difference equations driven by a zero-mean Gaussian random sequence.

Merrick, R. B.; Smith, G. L.

1972-01-01

216

An integrated GPS\\/INS\\/baro and radar altimeter system for aircraft precision approach landings  

Microsoft Academic Search

Currently, the Department of Defense (DOD) and the commercial airline industry are utilizing the Instrument Landing System (ILS) during aircraft landings for precision approaches. The replacement system for the aging ILS was thought to be the Microwave Landing System (MLS). Instead, use of the Global Positioning System (GPS) is now thought to be a viable replacement for ILS precision approaches.

Robert A. Gray; Peter S. Maybeck

1995-01-01

217

Vision-Aided Inertial Navigation for Precise Planetary Landing: Analysis and Experiments  

Microsoft Academic Search

In this paper, we present the analysis and experi- mental validation of a vision-aided inertial navigation algorithm for planetary landing applications. The system employs tight integration of inertial and visual feature measurements to com- pute accurate estimates of the lander's terrain-relative position, attitude, and velocity in real time. Two types of features are considered: mapped landmarks, i.e., features whose global

Anastasios I. Mourikis; Nikolas Trawny; Stergios I. Roumeliotis; Andrew Johnson; Larry Matthies

2007-01-01

218

Assessing land-use impacts on biodiversity using an expert systems tool  

USGS Publications Warehouse

Habitat alteration, in the form of land-use development, is a leading cause of biodiversity loss in the U.S. and elsewhere. Although statutes in the U.S. may require consideration of biodiversity in local land-use planning and regulation, local governments lack the data, resources, and expertise to routinely consider biotic impacts that result from permitted land uses. We hypothesized that decision support systems could aid solution of this problem. We developed a pilot biodiversity expert systems tool (BEST) to test that hypothesis and learn what additional scientific and technological advancements are required for broad implementation of such a system. BEST uses data from the U.S. Geological Survey's Gap Analysis Program (GAP) and other data in a desktop GIS environment. The system provides predictions of conflict between proposed land uses and biotic elements and is intended for use at the start of the development review process. Key challenges were the development of categorization systems that relate named land-use types to ecological impacts, and relate sensitivities of biota to ecological impact levels. Although the advent of GAP and sophisticated desktop GIS make such a system feasible for broad implementation, considerable ongoing research is required to make the results of such a system scientifically sound, informative, and reliable for the regulatory process. We define a role for local government involvement in biodiversity impact assessment, the need for a biodiversity decision support system, the development of a prototype system, and scientific needs for broad implementation of a robust and reliable system.

Crist, P.J.; Kohley, T.W.; Oakleaf, J.

2000-01-01

219

Land  

NSDL National Science Digital Library

The solid Earth is the foundation upon which the entire system rests, and provides the critical substrate and reservoir of raw materials the rest of the system. The solid Earth also records the past in the ...

220

Figure 1. Extent of the Kirkwood-Cohansey aquifer system in New Jersey, areas of agricultural land use, and locations of wells sampled for analysis of radium concentrations, 1988-96.  

E-print Network

Figure 1. Extent of the Kirkwood-Cohansey aquifer system in New Jersey, areas of agricultural land of the Interior U.S. Geological Survey Radium-226 and Radium-228 in Shallow Ground Water, Southern New Jersey Fact.S. Geological Survey (USGS) in cooperation with the New Jersey Department of Environmental Protection (NJDEP

221

Modeling and Simulation of the Second-Generation Orion Crew Module Air Bag Landing System  

NASA Technical Reports Server (NTRS)

Air bags were evaluated as the landing attenuation system for earth landing of the Orion Crew Module (CM). Analysis conducted to date shows that airbags are capable of providing a graceful landing of the CM in nominal and off-nominal conditions such as parachute failure, high horizontal winds, and unfavorable vehicle/ground angle combinations, while meeting crew and vehicle safety requirements. The analyses and associated testing presented here surround a second generation of the airbag design developed by ILC Dover, building off of relevant first-generation design, analysis, and testing efforts. In order to fully evaluate the second generation air bag design and correlate the dynamic simulations, a series of drop tests were carried out at NASA Langley s Landing and Impact Research (LandIR) facility in Hampton, Virginia. The tests consisted of a full-scale set of air bags attached to a full-scale test article representing the Orion Crew Module. The techniques used to collect experimental data, develop the simulations, and make comparisons to experimental data are discussed.

Timmers, Richard B.; Hardy, Robin C.; Willey, Cliff E.; Welch, Joseph V.

2009-01-01

222

75 FR 52713 - Nationwide Aerial Application of Fire Retardant on National Forest System Lands  

Federal Register 2010, 2011, 2012, 2013, 2014

...Service Nationwide Aerial Application of Fire Retardant on National Forest System Lands...continued nationwide aerial application of fire retardant on National Forest System lands...The Forest Service is working to restore fire-adapted ecosystems through...

2010-08-27

223

23 CFR 970.212 - Federal lands safety management system (SMS).  

Code of Federal Regulations, 2010 CFR

...Federal lands safety management system (SMS). 970.212 Section 970.212 Highways...Federal lands safety management system (SMS). In addition to the requirements provided in § 970.204, the SMS must meet the following...

2010-04-01

224

23 CFR 970.212 - Federal lands safety management system (SMS).  

Code of Federal Regulations, 2014 CFR

...Federal lands safety management system (SMS). 970.212 Section 970.212 Highways...Federal lands safety management system (SMS). In addition to the requirements provided in § 970.204, the SMS must meet the following...

2014-04-01

225

23 CFR 970.212 - Federal lands safety management system (SMS).  

Code of Federal Regulations, 2011 CFR

...Federal lands safety management system (SMS). 970.212 Section 970.212 Highways...Federal lands safety management system (SMS). In addition to the requirements provided in § 970.204, the SMS must meet the following...

2011-04-01

226

23 CFR 970.212 - Federal lands safety management system (SMS).  

Code of Federal Regulations, 2013 CFR

...Federal lands safety management system (SMS). 970.212 Section 970.212 Highways...Federal lands safety management system (SMS). In addition to the requirements provided in § 970.204, the SMS must meet the following...

2013-04-01

227

23 CFR 970.212 - Federal lands safety management system (SMS).  

Code of Federal Regulations, 2012 CFR

...Federal lands safety management system (SMS). 970.212 Section 970.212 Highways...Federal lands safety management system (SMS). In addition to the requirements provided in § 970.204, the SMS must meet the following...

2012-04-01

228

Models for estimating runway landing capacity with Microwave Landing System (MLS)  

NASA Technical Reports Server (NTRS)

A model is developed which is capable of computing the ultimate landing runway capacity, under ILS and MLS conditions, when aircraft population characteristics and air traffic control separation rules are given. This model can be applied in situations when only a horizontal separation between aircraft approaching a runway is allowed, as well as when both vertical and horizontal separations are possible. It is assumed that the system is free of errors, that is that aircraft arrive at specified points along the prescribed flight path precisely when the controllers intend for them to arrive at these points. Although in the real world there is no such thing as an error-free system, the assumption is adequate for a qualitative comparison of MLS with ILS. Results suggest that an increase in runway landing capacity, caused by introducing the MLS multiple approach paths, is to be expected only when an aircraft population consists of aircraft with significantly differing approach speeds and particularly in situations when vertical separation can be applied. Vertical separation can only be applied if one of the types of aircraft in the mix has a very steep descent angle.

Tosic, V.; Horonjeff, R.

1975-01-01

229

LAnd surface remote sensing Products VAlidation System (LAPVAS) and its preliminary application  

NASA Astrophysics Data System (ADS)

The long term record of remote sensing product shows the land surface parameters with spatial and temporal change to support regional and global scientific research widely. Remote sensing product with different sensors and different algorithms is necessary to be validated to ensure the high quality remote sensing product. Investigation about the remote sensing product validation shows that it is a complex processing both the quality of in-situ data requirement and method of precision assessment. A comprehensive validation should be needed with long time series and multiple land surface types. So a system named as land surface remote sensing product is designed in this paper to assess the uncertainty information of the remote sensing products based on a amount of in situ data and the validation techniques. The designed validation system platform consists of three parts: Validation databases Precision analysis subsystem, Inter-external interface of system. These three parts are built by some essential service modules, such as Data-Read service modules, Data-Insert service modules, Data-Associated service modules, Precision-Analysis service modules, Scale-Change service modules and so on. To run the validation system platform, users could order these service modules and choreograph them by the user interactive and then compete the validation tasks of remote sensing products (such as LAI ,ALBEDO ,VI etc.) . Taking SOA-based architecture as the framework of this system. The benefit of this architecture is the good service modules which could be independent of any development environment by standards such as the Web-Service Description Language(WSDL). The standard language: C++ and java will used as the primary programming language to create service modules. One of the key land surface parameter, albedo, is selected as an example of the system application. It is illustrated that the LAPVAS has a good performance to implement the land surface remote sensing product validation.

Lin, Xingwen; Wen, Jianguang; Tang, Yong; Ma, Mingguo; Dou, Baocheng; Wu, Xiaodan; Meng, Lumin

2014-11-01

230

Improved Modeling of Land-Atmosphere Interactions using a Coupled Version of WRF with the Land Information System  

NASA Technical Reports Server (NTRS)

The exchange of energy and moisture between the Earth's surface and the atmospheric boundary layer plays a critical role in many hydrometeorological processes. Accurate and high-resolution representations of surface properties such as sea-surface temperature (SST), vegetation, soil temperature and moisture content, and ground fluxes are necessary to better understand the Earth-atmosphere interactions and improve numerical predictions of weather and climate phenomena. The NASA/NWS Short-term Prediction Research and Transition (SPORT) Center is currently investigating the potential benefits of assimilating high-resolution datasets derived from the NASA moderate resolution imaging spectroradiometer (MODIS) instruments using the Weather Research and Forecasting (WRF) model and the Goddard Space Flight Center Land Information System (LIS). The LIS is a software framework that integrates satellite and ground-based observational and modeled data along with multiple land surface models (LSMs) and advanced computing tools to accurately characterize land surface states and fluxes. The LIS can be run uncoupled to provide a high-resolution land surface initial condition, and can also be run in a coupled mode with WRF to integrate surface and soil quantities using any of the LSMs available in LIS. The LIS also includes the ability to optimize the initialization of surface and soil variables by tuning the spin-up time period and atmospheric forcing parameters, which cannot be done in the standard WRF. Among the datasets available from MODIS, a leaf-area index field and composite SST analysis are used to improve the lower boundary and initial conditions to the LIS/WRF coupled model over both land and water. Experiments will be conducted to measure the potential benefits from using the coupled LIS/WRF model over the Florida peninsula during May 2004. This month experienced relatively benign weather conditions, which will allow the experiments to focus on the local and mesoscale impacts of the high-resolution MODIS datasets and optimized soil and surface initial conditions. Follow-on experiments will examine the utility of such an optimized WRF configuration for more complex weather scenarios such as convective initiation. This paper will provide an overview of the experiment design and present preliminary results from selected cases in May 2004.

Case, Jonathan L.; LaCasse, Katherine M.; Santanello, Joseph A., Jr.; Lapenta, William M.; Petars-Lidard, Christa D.

2007-01-01

231

A satellite system for land-mobile communications in Europe  

NASA Technical Reports Server (NTRS)

There exists a great unsatisified demand for land mobile communications in Europe, particularly in sectors of business activity such as the road transport industry. This demand could best be satisfied by means of satellite-based private networks providing voice and data communications in a hub configuration. The potential market is estimated to encompass several hundred thousand road vehicles and the transmission capacity required would be several thousand channels. ESA is currently demonstrating the potential of satellite communications for this type of application, using a system called PRODAT. System studies are being performed with the aim of defining the architecture of a regional satellite system for Europe.

Bartholome, P.; Rogard, R.

1988-01-01

232

Mathematical Analysis of Relationship between Land Price and Real Estate Bubbles  

Microsoft Academic Search

In the article, the author studies the relationship between land price and real estate bubbles through mathematical analysis. Firstly, through analyzing the situation in foreign countries, the author points out that the rising price of land makes the price of real estate keep rising because the land price is the most important part of real estate price. This is the

Lv Bo; Zhang Ming-yu

2006-01-01

233

Land Tenure and the Cadastral System of Mali University of Maine, Department of Spatial Information Engineering  

E-print Network

1 Land Tenure and the Cadastral System of Mali Ted Wells University of Maine, Department of Spatial Information Engineering Cadastral and Land Information Systems-SIE526 May 1999 ABSTRACT This paper is an introduction to the history of land tenure and cadastral systems in the sub-Saharan country of Mali in West

Onsrud, Harlan J.

234

Unmanned Aircraft Systems for Monitoring Department of the Interior Lands  

NASA Astrophysics Data System (ADS)

Unmanned Aircraft Systems (UAS) technology is quickly evolving and will have a significant impact on Earth science research. The U.S. Geological Survey (USGS) is conducting an operational test and evaluation of UAS to see how this technology supports the mission of the Department of the Interior (DOI). Over the last 4 years, the USGS, working with many partners, has been actively conducting proof of concept UAS operations, which are designed to evaluate the potential of UAS technology to support the mandated DOI scientific, resource and land management missions. UAS technology is being made available to monitor environmental conditions, analyze the impacts of climate change, respond to natural hazards, understand landscape change rates and consequences, conduct wildlife inventories and support related land management and law enforcement missions. Using small UAS (sUAS), the USGS is able to tailor solutions to meet project requirements by obtaining very high resolution video data, acquiring thermal imagery, detecting chemical plumes, and generating digital terrain models at a fraction of the cost of conventional surveying methods. UAS technology is providing a mechanism to collect timely remote sensing data at a low cost and at low risk over DOI lands that can be difficult to monitor and consequently enhances our ability to provide unbiased scientific information to better enable decision makers to make informed decisions. This presentation describes the UAS technology and infrastructure being employed, the application projects already accomplished, lessons learned and future of UAS within the DOI. We fully expect that by 2020 UAS will emerge as a primary platform for all DOI remote sensing applications. Much like the use of Internet technology, Geographic Information Systems (GIS) and Global Positioning Systems (GPS), UAS have the potential of enabling the DOI to be better stewards of the land.

Hutt, M. E.; Quirk, B.

2013-12-01

235

Land-use planning of Volyn region (Ukraine) using Geographic Information Systems (GIS) technologies  

NASA Astrophysics Data System (ADS)

Land-use development planning is carried out in order to create a favourable environment for human life, sustainable socioeconomic and spatial development. Landscape planning is an important part of land-use development that aims to meet the fundamental principles of sustainable development. Geographic Information Systems (GIS) is a fundamental tool to make a better landscape planning at different territorial levels, providing data and maps to support decision making. The objective of this work is to create spatio-temporal, territorial and ecological model of development of Volyn region (Ukraine). It is based on existing spatial raster and vector data and includes the analysis of territory dynamics as the aspects responsible for it. A spatial analyst tool was used to zone the areas according to their environmental components and economic activity. This analysis is fundamental to define the basic parameters of sustainability of Volyn region. To carry out this analysis, we determined the demographic capacity of districts and the analysis of spatial parameters of land use. On the basis of the existing natural resources, we observed that there is a need of landscape protection and integration of more are natural areas in the Pan-European Ecological Network. Using GIS technologies to landscape planning in Volyn region, allowed us to identify, natural areas of interest, contribute to a better resource management and conflict resolution. Geographic Information Systems will help to formulate and implement landscape policies, reform the existing administrative system of Volyn region and contribute to a better sustainable development.

Strielko, Irina; Pereira, Paulo

2014-05-01

236

Analysis of continuous GPS measurements from southern Victoria Land, Antarctica  

USGS Publications Warehouse

Several years of continuous data have been collected at remote bedrock Global Positioning System (GPS) sites in southern Victoria Land, Antarctica. Annual to sub-annual variations are observed in the position time-series. An atmospheric pressure loading (APL) effect is calculated from pressure field anomalies supplied by the European Centre for Medium-Range Weather Forecasts (ECMWF) model loading an elastic Earth model. The predicted APL signal has a moderate correlation with the vertical position time-series at McMurdo, Ross Island (International Global Navigation Satellite System Service (IGS) station MCM4), produced using a global solution. In contrast, a local solution in which MCM4 is the fiducial site generates a vertical time series for a remote site in Victoria Land (Cape Roberts, ROB4) which exhibits a low, inverse correlation with the predicted atmospheric pressure loading signal. If, in the future, known and well modeled geophysical loads can be separated from the time-series, then local hydrological loading, of interest for glaciological and climate applications, can potentially be extracted from the GPS time-series.

Willis, Michael J.

2007-01-01

237

Human Planetary Landing System (HPLS) Capability Roadmap: Wrap Up  

NASA Technical Reports Server (NTRS)

When and how does the full scale system and subsystems need to be qualified & Human-rated for flight? Answer: No later than 29. Full scale AEDL Flight Tests can and should be done at Earth (need to get fast turn around between multiple tests). Do we need a Full Scale Validation Flight Test at Mars? Answer: Not, specifically, but the AEDL community is very uncomfortable with the notion of the very first full scale AEDL being piloted. The full scale unpiloted AEDL advance cargo mission that immediately precedes the human landing could do the trick. What kind of precursor AEDL Flight Tests are needed at Mars? Answer: We need to validate our performance & aerodynamic models by flying a scaled (1/10th?) version of the Full Scale Mission by 22. When and how do we decide on the AEDL system to fly? Answer: No later than 2015 (earlier is harder). We need to do multi-path full scale flight simulations and subscale / component development testing starting ASAP. If we find an AEDL for a landing mass of 40 MT, will this same architecture and technology paradigm extend to landing 80 MT? 120 MT? Is there another break point? Answer: We do not know yet.

Manning, Rob

2005-01-01

238

Integrating land management into Earth system models: the importance of land use transitions at sub-grid-scale  

NASA Astrophysics Data System (ADS)

Recent studies indicate that changes in surface climate and carbon fluxes caused by land management (i.e., modifications of vegetation structure without changing the type of land cover) can be as large as those caused by land cover change. Further, such effects may occur on substantial areas: while about one quarter of the land surface has undergone land cover change, another fifty percent are managed. This calls for integration of management processes in Earth system models (ESMs). This integration increases the importance of awareness and agreement on how to diagnose effects of land use in ESMs to avoid additional model spread and thus unnecessary uncertainties in carbon budget estimates. Process understanding of management effects, their model implementation, as well as data availability on management type and extent pose challenges. In this respect, a significant step forward has been done in the framework of the current IPCC's CMIP5 simulations (Coupled Model Intercomparison Project Phase 5): The climate simulations were driven with the same harmonized land use dataset that, different from most datasets commonly used before, included information on two important types of management: wood harvest and shifting cultivation. However, these new aspects were employed by only part of the CMIP5 models, while most models continued to use the associated land cover maps. Here, we explore the consequences for the carbon cycle of including subgrid-scale land transformations ("gross transitions"), such as shifting cultivation, as example of the current state of implementation of land management in ESMs. Accounting for gross transitions is expected to increase land use emissions because it represents simultaneous clearing and regrowth of natural vegetation in different parts of the grid cell, reducing standing carbon stocks. This process cannot be captured by prescribing land cover maps ("net transitions"). Using the MPI-ESM we find that ignoring gross transitions underestimates emissions substantially, for historical times by about 40%. Implementation of land management such as gross transitions is a step forward in terms of comprehensiveness of simulated processes. However, it has increased model spread in carbon fluxes, because land management processes have been considered by only a subset of recent ESMs contributing to major projects such as IPCC or the Global Carbon Project. This model spread still causes the net land use flux to be the most uncertain component in the global carbon budget. Other causes have previously been identified as differences in land use datasets, differing types of vegetation model, accounting of nutrient limitation, the inclusion of land use feedbacks (increase in atmospheric CO2 due to land use emissions causing terrestrial carbon uptake), and a confusion of whether the net land use flux in ESMs should be reported as instantaneous emissions, or also account for delayed carbon responses and regrowth. These differences explain a factor 2-6 difference between model estimates and are expected to be further affected by interactions with land management. This highlights the importance of an accurate protocol for future model intercomparisons of carbon fluxes from land cover change and land management to ensure comparison of the same processes and fluxes.

Pongratz, Julia; Wilkenskjeld, Stiig; Kloster, Silvia; Reick, Christian

2014-05-01

239

An investigation of an active landing gear system to reduce aircraft vibrations caused by landing impacts and runway excitations  

NASA Astrophysics Data System (ADS)

A mathematical model is developed to control aircraft vibrations caused by runway excitation using an active landing gear system. Equations are derived to describe the integrated aircraft-active system. The nonlinear characteristics of the system are modelled and it is actively controlled using a Proportional Integral Derivative (PID) strategy. The performance of this system and its corresponding passive system are compared using numerical simulations. It is demonstrated that the impact loads and the vertical displacement of the aircraft's centre of gravity caused by landing and runway excitations are greatly reduced using the active system, which result in improvements to the performance of the landing gear system, benefits the aircraft's fatigue life, taxiing performance, crew/passenger comfort and reduces requirements on the unevenness of runways.

Wang, Haitao; Xing, J. T.; Price, W. G.; Li, Weiji

2008-10-01

240

Evolution of INMARSAT systems and applications: The land mobile experience  

NASA Technical Reports Server (NTRS)

Inmarsat has provided mobile satellite communication services for land mobile applications for well over a decade. Having started with the Inmarsat-A voice and telex system, Inmarsat is committed to the evolution of services towards a global personal, handheld satellite communicator. Over the years, users have benefitted from the evolution of technologies, increased user friendliness and portability of terminals and ever decreasing cost of operations. This paper describes the various present systems, their characteristics and applications, and outlines their contributions in the evolution towards the personal global communicator.

Staffa, Eugene; Subramaniam, Ram

1993-01-01

241

Land-use change analysis in Yulin prefecture, northwestern China using remote sensing and GIS  

Microsoft Academic Search

Rapid land-use change has taken place in many arid and semi-arid regions of China such as Yulin prefecture over the last decade due to rehabilitation measures. In this paper, land-use change dynamics were investigated by the combined use of satellite remote sensing and geographical information systems (GIS). Our objectives were to determine land-use transition rates among land-use types in Yulin

Z. Li; X. Li; Y. Wang; A. Ma; J. Wang

2004-01-01

242

The future of olive plantation systems on sloping and mountainous land; scenarios for production and natural resource conservation, First Annual Report. EU project Olivero  

Microsoft Academic Search

The project will devote itself to the future of olive plantation systems on sloping and mountainous land in southern Europe. These systems have been affected by emigration of local populations and fierce competition from low land plantations and from non-EU countries, and are currently neither productive nor sustainable. The project will undertake a thorough analysis of production, ecological and socio-economic

L. Fleskens; L. Stroosnijder; Graaff de J

2004-01-01

243

Triple L -Land, Livestock and Livelihood Dynamics in Dryland Systems, West Pokot, Kenya  

E-print Network

Triple L - Land, Livestock and Livelihood Dynamics in Dryland Systems, West Pokot, Kenya Background; systems often associated with problems of overgrazing and land degradation. Ever since Hardin's (1968) seminal paper on the tragedy of the commons, the question of sustainable land management in pastoralist

244

Scaled Measurements of Instrument-Landing-System Disturbances Due to Large Taxiing Aircraft  

Microsoft Academic Search

It is commonly known that the directional pattern of the instrument landing system (ILS)-localizer antenna system, which constitutes the landing-course information for approaching aircraft, can be disturbed by reflections from large aircraft on the ground. Therefore, airport operators are interested in knowing configurations of landed and taxiing aircraft that lead to such ILS disturbance scenarios. Measurements on a real airport

Robert Geise; Achim Enders; Helge Vahle; Harald Spieker

2008-01-01

245

Height estimation via stereo vision system for unmanned helicopter autonomous landing  

Microsoft Academic Search

Auto landing is a very important function of control in the development of autonomous unmanned helicopters. In this paper, the stereo vision system is proposed to provide the height information on landing control instead of global positioning system (GPS). GPS provided 3-axis information, but the height error of GPS is usually in meters, which is not accurate enough for landing.

Kuo-Hsien Hsia; Shao-Fan Lien; Juhng-Perng Su

2010-01-01

246

Using the Nordic Geodetic Observing System for land uplift studies  

NASA Astrophysics Data System (ADS)

Geodetic observing systems have been planned and developed during the last decade. An ideal observing system consists of a network of geodetic observing stations with several techniques at the same site, publicly accessible databases, and as a product delivers data time series, combination of techniques or some other results obtained from the data sets. Globally, there is the International Association of Geodesy (IAG) Global Geodetic Observing System (GGOS), and there are ongoing attempts to create also regional observing systems. In this paper we introduce one regional system, the Nordic Geodetic Observing System (NGOS) hosted by the Nordic Geodetic Commission (NKG). Data availability and accessibility are one of the major issues today. We discuss in general data-related topics, and introduce a pilot database project of NGOS. As a demonstration of the use of such a database, we apply it for postglacial rebound studies in the Fennoscandian area. We compare land uplift values from three techniques, GNSS, tide gauges and absolute gravity, with the Nordic Geodetic Commission NKG2005LU land uplift model for Fennoscandia. The purpose is to evaluate the data obtained from different techniques and different sources and get the most reliable values for the uplift using publicly available data. The primary aim of observing systems will be to produce data and other products needed by multidisciplinary projects, such as Upper Mantle Dynamics and Quaternary Climate in Cratonic Areas (DynaQlim) or the European Plate Observing System (EPOS), but their needs may currently exceed the scope of an existing observing system. We discuss what requirements the projects pose to observing systems and their development. To make comparisons between different studies possible and reliable, the researcher should document what they have in detail, either in appendixes, supplementary material or some other available format.

Nordman, M.; Poutanen, M.; Kairus, A.; Virtanen, J.

2014-07-01

247

Development and application of a benchmarking system for land models (Invited)  

NASA Astrophysics Data System (ADS)

There is a widely understood need for improved assessment of terrestrial system models that are utilized in climate, weather, and ecosystem modeling. A more comprehensive and more systematic land model ';benchmarking' process should help speed the development of new parameterizations, improve the design of new measurement campaigns, and reduce uncertainties associated with key land surface processes. However, the development of informative metrics is non-trivial. Past data-model intercomparisons have certainly strengthened the representation of key processes in land models, but often this information has not been easily accessible for use by other modeling teams or in future intercomparisons. Further, the development of sophisticated model diagnostics programs--that can fully exploit the richness of large Earth System data sets like satellite or Fluxnet measurements--are outside the scope of any single investigator. Here, we will describe progress in the development of a comprehensive (and extensible) land model analysis system that spans water, energy, carbon, and vegetation dynamics metrics. Several classes of metrics are employed including (1) large-scale state and flux estimates (e.g., soil C, atmospheric CO2 cycle, surface temperatures, GRACE water budget estimates, river discharge); (2) functional responses of explicitly modeled and emergent processes (e.g., stomatal responses to VPD, near-surface soil moisture responses to precipitation); and (3) experimental manipulation responses (e.g., N additions, FACE, warming). We will demonstrate the application of selected metrics to several versions of the Community Land Model (principally CLM4 and CLM4.5 and variants therein). Additionally, we will discuss how the analysis package, which is open source and modular, is designed to be extensible and improved by many different modeling and measurement teams.

Lawrence, D. M.; Randerson, J. T.; Mu, M.; Hoffman, F. M.; Riley, W. J.; Koven, C. D.; Todd-Brown, K. E.; Keppel-Aleks, G.

2013-12-01

248

Seasonal-scale Observational Data Analysis and Atmospheric Phenomenology for the Cold Land Processes Experiment  

NASA Technical Reports Server (NTRS)

The Cold Land Processes Experiment (CLPX) experiment emphasized the development of a strong synergism between process-oriented understanding, land surface models and microwave remote sensing. Our work sought to investigate which topographically- generated atmospheric phenomena are most relevant to the CLPX MSA's for the purpose of evaluating their climatic importance to net local moisture fluxes and snow transport through the use of high-resolution data assimilation/atmospheric numerical modeling techniques. Our task was to create three long-term, scientific quality atmospheric datasets for quantitative analysis (for all CLPX researchers) and provide a summary of the meteorologically-relevant phenomena of the three MSAs (see Figure) over northern Colorado. Our efforts required the ingest of a variety of CLPX datasets and the execution an atmospheric and land surface data assimilation system based on the Navier-Stokes equations (the Local Analysis and Prediction System, LAPS, and an atmospheric numerical weather prediction model, as required) at topographically- relevant grid spacing (approx. 500 m). The resulting dataset will be analyzed by the CLPX community as a part of their larger research goals to determine the relative influence of various atmospheric phenomena on processes relevant to CLPX scientific goals.

Poulos, Gregory S.; Stamus, Peter A.; Snook, John S.

2005-01-01

249

Surface Hydrology in Global River Basins in the Off-Line Land-Surface GEOS Assimilation (OLGA) System  

NASA Technical Reports Server (NTRS)

Land surface hydrology for the Off-line Land-surface GEOS Analysis (OLGA) system and Goddard Earth Observing System (GEOS-1) Data Assimilation System (DAS) has been examined using a river routing model. The GEOS-1 DAS land-surface parameterization is very simple, using an energy balance prediction of surface temperature and prescribed soil water. OLGA uses near-surface atmospheric data from the GEOS-1 DAS to drive a more comprehensive parameterization of the land-surface physics. The two global systems are evaluated using a global river routing model. The river routing model uses climatologic surface runoff from each system to simulate the river discharge from global river basins, which can be compared to climatologic river discharge. Due to the soil hydrology, the OLGA system shows a general improvement in the simulation of river discharge compared to the GEOS-1 DAS. Snowmelt processes included in OLGA also have a positive effect on the annual cycle of river discharge and source runoff. Preliminary tests of a coupled land-atmosphere model indicate improvements to the hydrologic cycle compared to the uncoupled system. The river routing model has provided a useful tool in the evaluation of the GCM hydrologic cycle, and has helped quantify the influence of the more advanced land surface model.

Bosilovich, Michael G.; Yang, Runhua; Houser, Paul R.

1998-01-01

250

Mars Science Laboratory: Entry, Descent, and Landing System Performance  

NASA Technical Reports Server (NTRS)

In 2010, the Mars Science Laboratory (MSL) mission will pioneer the next generation of robotic Entry, Descent, and Landing (EDL) systems, by delivering the largest and most capable rover to date to the surface of Mars. To do so, MSL will fly a guided lifting entry at a lift-to-drag ratio in excess of that ever flown at Mars, deploy the largest parachute ever at Mars, and perform a novel Sky Crane maneuver. Through improved altitude capability, increased latitude coverage, and more accurate payload delivery, MSL is allowing the science community to consider the exploration of previously inaccessible regions of the planet. The MSL EDL system is a new EDL architecture based on Viking heritage technologies and designed to meet the challenges of landing increasing massive payloads on Mars. In accordance with level-1 requirements, the MSL EDL system is being designed to land an 850 kg rover to altitudes as high as 1 km above the Mars Orbiter Laser Altimeter defined areoid within 10 km of the desired landing site. Accordingly, MSL will enter the largest entry mass, fly the largest 70 degree sphere-cone aeroshell, generate the largest hypersonic lift-to-drag ratio, and deploy the largest Disk-Gap-Band supersonic parachute of any previous mission to Mars. Major EDL events include a hypersonic guided entry, supersonic parachute deploy and inflation, subsonic heatshield jettison, terminal descent sensor acquisition, powered descent initiation, sky crane terminal descent, rover touchdown detection, and descent stage flyaway. Key performance metrics, derived from level-1 requirements and tracked by the EDL design team to indicate performance capability and timeline margins, include altitude and range at parachute deploy, time on radar, and propellant use. The MSL EDL system, which will continue to develop over the next three years, will enable a notable extension in the advancement of Mars surface science by delivering more science capability than ever before to the surface of Mars. This paper describes the current MSL EDL system performance as predicted by end-to-end EDL simulations, highlights the sensitivity of this baseline performance to several key environmental assumptions, and discusses some of the challenges faced in delivering such an unprecedented rover payload to the surface of Mars.

Way, David W.; Powell, Richard W.; Chen, Allen; Steltzner, Adam D.; San Martin, Alejandro M.; Burkhart, Paul D.; mendeck, Gavin F.

2006-01-01

251

Mars Science Laboratory: Entry, Descent, and Landing System Performance  

NASA Technical Reports Server (NTRS)

In 2010, the Mars Science Laboratory (MSL) mission will pioneer the next generation of robotic Entry, Descent, and Landing (EDL) systems, by delivering the largest and most capable rover to date to the surface of Mars. To do so, MSL will fly a guided lifting entry at a lift-to-drag ratio in excess of that ever flown at Mars, deploy the largest parachute ever at Mars, and perform a novel Sky Crane maneuver. Through improved altitude capability, increased latitude coverage, and more accurate payload delivery, MSL is allowing the science community to consider the exploration of previously inaccessible regions of the planet. The MSL EDL system is a new EDL architecture based on Viking heritage technologies and designed to meet the challenges of landing increasing massive payloads on Mars. In accordance with level-1 requirements, the MSL EDL system is being designed to land an 850 kg rover to altitudes as high as 1 km above the Mars Orbiter Laser Altimeter defined areoid within 10 km of the desired landing site. Accordingly, MSL will enter the largest entry mass, fly the largest 70 degree sphere-cone aeroshell, generate the largest hypersonic lift-to-drag ratio, and deploy the largest Disk-Gap-Band supersonic parachute of any previous mission to Mars. Major EDL events include a hypersonic guided entry, supersonic parachute deploy and inflation, subsonic heatshield jettison, terminal descent sensor acquisition, powered descent initiation, sky crane terminal descent, rover touchdown detection, and descent stage flyaway. Key performance metrics, derived from level-1 requirements and tracked by the EDL design team to indicate performance capability and timeline margins, include altitude and range at parachute deploy, time on radar, and propellant use. The MSL EDL system, which will continue to develop over the next three years, will enable a notable extension in the advancement of Mars surface science by delivering more science capability than ever before to the surface of Mars. This paper describes the current MSL EDL system performance as predicted by end-to-end EDL simulations, highlights the sensitivity of this baseline performance to several key environmental assumptions, and discusses some of the challenges faced in delivering such an unprecedented rover payload to the surface of Mars.

Way, David W.; Powell, Richard W.; Chen, Allen; SanMartin, A. Miguel; Burkhart, P. Daniel; Mendeck, Gavin F.

2007-01-01

252

Carbon-Structural Analysis of Global Land Models (C-SALM)  

NASA Astrophysics Data System (ADS)

Abstract Better understanding of terrestrial carbon cycle is taking an increased scientific attention in the present era of climate change. Representation of the global carbon cycle is increasingly becoming complex in land models which results in large uncertainties in modeled outputs. Therefore, it is urgent to promote methods for quantitative and critical assessment of the models. Here we apply a systematic computational framework for Carbon-Structural Analysis of Global Land Model (C-SALM). The models used in this study are NCAR's Community Land Models (versions CLM3.5, CLM4.0 and CLM4.5) present in Community Earth System Model (CESM), Australian Community Atmosphere Biosphere Land Exchange (CABLE) and Common Land Model (CoLM) of China. The framework applied in this study facilitates the effective model comparison by decomposing a complex land model into traceable components based on fundamental properties of biogeochemical processes implemented in these models. The framework defines ecosystem carbon storage capacity (Xss) as a product of net primary productivity (NPP) and ecosystem residence time (?E). The ?E is determined by (i) baseline carbon residence times (??E), (ii) environmental scalars (?), and (iii) environmental forcings (Xia et al., 2013). The ??E can be further traced by partitioning coefficients (called vector B) and transfer coefficients (called A & C matrices) of NPP. To compare land models, the steady state annual average outputs were computed using 1990 forcing data at 1x1o resolution. The carbon storage capacity of each model was found to be determined differently which are due to differences present in carbon residence time and environmental scalars. The dependency of ? was assessed based on temperature (?T) and water (?W) scalars. This study explains the carbon model pool structure for each model and identifies the A, B and C elements at each carbon pool. The C-SALM study also evaluates models at major plant functional types (PFTs) level and traces major differences in terms of ?E, ??E and ? in each model. Climate forcings which control decomposition rates were found to be different at PFT level for each model. The approximation errors raised due to temporal variations of A, B, C and ? were evaluated at PFT level for each model. Information from C-SALM is helpful in enhancing the understanding of land model performance and reducing uncertainty in model output. Furthermore, this study has a range of implications for future model development and inter-comparison. Reference: Xia J, Luo Y, Wang YP, Hararuk O (2013) Traceable components of terrestrial carbon storage capacity in biogeochemical models. Global Change Biology, 19, 2104-2116.

Rafique, R.; Xia, J.; Hararuk, O.; Luo, Y.; Dai, Y.; Macaulay, C.

2013-12-01

253

Carbon balances during land conversion in early bioenergy systems  

NASA Astrophysics Data System (ADS)

In this study, we established a field experiment and deployed seven eddy-covariance towers to quantify the roles of land use change and the subsequent carbon (C) balances of three different bioenergy systems (corn, switchgrass, and mixed prairie species) that were developed from two historical land use types: monocultural grasslands dominated by smooth brome (Bromus inermis Leyss) and lands in the Conservation Reserve Program (CRP). Three CRP fields and three cropland fields were converted to soybean in 2009 (conversion year) before establishing the cellulosic biofuel cropping systems in 2010 (establishment year). A CRP perennial grassland site was kept undisturbed as a reference. Conversion of CRP to soybean induced net C emissions during the conversion year (134 -262 g C m-2 yr-1), while in the same year the net C balance at the CRP grassland reference was -35 g C m-2 yr-1 (i.e., net C sequestration). The establishment of switchgrass and mixed prairie induced a cumulative C balance of -113 g C m-2 (switchgrass from CRP), 250 g C m-2 (switchgrass from cropland), 706 g C m-2 (mixed prairie from CRP), and 59 g C m-2 (mixed prairie from cropland) over the three-year study period. The cumulative three-year C balance of corn converted from CRP and from cropland was -151 g C m-2 and -183 g C m-2, respectively. Eddy flux measurements during cellulosic biofuel crop establishment reveal annual changes in C balance that cannot be detected using conventional mass balance approaches. When end-use of harvested biomass was considered, the C balances for all studied systems, except the reference site, exhibited large C emissions ranging from 150 to 990 g C m-2 over the three-year conversion phase.

Zenone, T.; Chen, J.; Gelfand, I.; Robertson, G. P.; Hamilton, S. K.

2012-12-01

254

REDUCING STORMWATER RUNOFF THROUGH LAND SUITABILITY ANALYSIS AND LOW-IMPACT SUBDIVISION DESIGN  

Technology Transfer Automated Retrieval System (TEKTRAN)

We demonstrate an approach to reduce the anticipated increase in stormwater runoff from development under conventional subdivision design by incorporating hydrologic factors into a land suitability analysis and a low-impact subdivision design. A typical land suitability analysis assesses attributes ...

255

Simulated final approach path captures using the microwave landing system  

NASA Technical Reports Server (NTRS)

Computer simulation results are presented for intercepting final approach paths using various Microwave Landing System (MLS) path capture concepts. This study, conducted under the Advanced Transport Operating System (ATOPS) program, simulated these captures using the MD-80 aircraft as the study model. Several different capture concepts were investigated. Systems that could be retrofitted into existing aircraft with minimum hardware and software changes were considered. An enhanced ILS look-alike capture provided improved tracking performance over conventional ILS without using a full-up path computer. The other concepts used waypoint databases and path computers to provide smart captures. These captures included lateral path intercepts as well as vertical path control. Winds, turbulence, and MLS noise were included in the simulation. In all cases, acceptable tracking errors were obtained during transition to the final approach path.

Feather, J. B.

1988-01-01

256

Land Data Assimilation of Satellite-Based Soil Moisture Products Using the Land Information System Over the NLDAS Domain  

NASA Technical Reports Server (NTRS)

This presentation will include results from data assimilation simulations using the NASA-developed Land Information System (LIS). Using the ensemble Kalman filter in LIS, two satellite-based soil moisture products from the AMSR-E instrument were assimilated, one a NASA-based product and the other from the Land Parameter Retrieval Model (LPRM). The domain and land-surface forcing data from these simulations were from the North American Land Data Assimilation System Phase-2, over the period 2002-2008. The Noah land-surface model, version 3.2, was used during the simulations. Changes to estimates of land surface states, such as soil moisture, as well as changes to simulated runoff/streamflow will be presented. Comparisons over the NLDAS domain will also be made to two global reference evapotranspiration (ET) products, one an interpolated product based on FLUXNET tower data and the other a satellite- based algorithm from the MODIS instrument. Results of an improvement metric show that assimilating the LPRM product improved simulated ET estimates while the NASA-based soil moisture product did not.

Mocko, David M.; Kumar, S. V.; Peters-Lidard, C. D.; Tian, Y.

2011-01-01

257

Analysis of Links Positions in Landing Gear Mechanism  

NASA Astrophysics Data System (ADS)

This article contains a kinematic analysis of an aircraft chassis mechanism in a range of positions. The mechanism of the chassis is made up of several smaller subsystems with different functions. The first mechanism is used to eject the chassis before landing (touchdown) and fold it to hatchway after the lift off. The second mechanism is designed to perform rotation of the crossover with the wheel, in order to adjust the position of the wheel to fit it in the limited space in the hold. The third mechanism allows movement of the chassis resulting from the change in length of the damper. To determine the position of the following links of the mechanism calculus of vectors was applied in which unit vectors were used to represent the angular position of the links. The aim of the analysis is to determine the angle of convergence and the angle of heel wheels as a function of the variable length of hydraulic cylinder, length of the shock absorber, length of the regulations rods

Brewczy?ski, D.; Tora, G.

2014-08-01

258

Navigation for space shuttle approach and landing using an inertial navigation system augmented by data from a precision ranging system or a microwave scan beam landing guidance system  

NASA Technical Reports Server (NTRS)

A preliminary study has been made of the navigation performance which might be achieved for the high cross-range space shuttle orbiter during final approach and landing by using an optimally augmented inertial navigation system. Computed navigation accuracies are presented for an on-board inertial navigation system augmented (by means of an optimal filter algorithm) with data from two different ground navigation aids; a precision ranging system and a microwave scanning beam landing guidance system. These results show that augmentation with either type of ground navigation aid is capable of providing a navigation performance at touchdown which should be adequate for the space shuttle. In addition, adequate navigation performance for space shuttle landing is obtainable from the precision ranging system even with a complete dropout of precision range measurements as much as 100 seconds before touchdown.

Mcgee, L. A.; Smith, G. L.; Hegarty, D. M.; Merrick, R. B.; Carson, T. M.; Schmidt, S. F.

1970-01-01

259

Application of scenario analysis and multiagent technique in land-use planning: a case study on Sanjiang wetlands.  

PubMed

Land-use planning has triggered debates on social and environmental values, in which two key questions will be faced: one is how to see different planning simulation results instantaneously and apply the results back to interactively assist planning work; the other is how to ensure that the planning simulation result is scientific and accurate. To answer these questions, the objective of this paper is to analyze whether and how a bridge can be built between qualitative and quantitative approaches for land-use planning work and to find out a way to overcome the gap that exists between the ability to construct computer simulation models to aid integrated land-use plan making and the demand for them by planning professionals. The study presented a theoretical framework of land-use planning based on scenario analysis (SA) method and multiagent system (MAS) simulation integration and selected freshwater wetlands in the Sanjiang Plain of China as a case study area. Study results showed that MAS simulation technique emphasizing quantitative process effectively compensated for the SA method emphasizing qualitative process, which realized the organic combination of qualitative and quantitative land-use planning work, and then provided a new idea and method for the land-use planning and sustainable managements of land resources. PMID:23818816

Yu, Huan; Ni, Shi-Jun; Kong, Bo; He, Zheng-Wei; Zhang, Cheng-Jiang; Zhang, Shu-Qing; Pan, Xin; Xia, Chao-Xu; Li, Xuan-Qiong

2013-01-01

260

Object-oriented image analysis and change detection of land-use on Tenerife related to socio-economic conditions  

NASA Astrophysics Data System (ADS)

The island Tenerife is characterized by an increasing tourism, which causes an enormous change of the socio-economic situation and a rural exodus. This development leads - beside for example sociocultural issues - to fallow land, decreasing settlements, land wasting etc., as well as to an economic and ecological problem. This causes to a growing interest in geoecological aspects and to an increasing demand for an adequate monitoring database. In order to study the change of land use and land cover, the technology of remote sensing (LANDSAT 3 MSS and 7 ETM+, orthophotos) and geographical information systems were used to analyze the spatial pattern and its spatial temporal changes of land use from end of the 70s to the present in different scales. Because of the heterogeneous landscape and the unsatisfactory experience with pixel-based classification of the same area, object-oriented image analysis techniques have been applied to classify the remote sensed data. A post-classification application was implemented to detect spatial and categorical land use and land cover changes, which have been clipped with the socio-economic data within GIS to derive the driving forces of the changes and their variability in time and space.

Naumann, Simone; Siegmund, Alexander

2004-10-01

261

Application of Scenario Analysis and Multiagent Technique in Land-Use Planning: A Case Study on Sanjiang Wetlands  

PubMed Central

Land-use planning has triggered debates on social and environmental values, in which two key questions will be faced: one is how to see different planning simulation results instantaneously and apply the results back to interactively assist planning work; the other is how to ensure that the planning simulation result is scientific and accurate. To answer these questions, the objective of this paper is to analyze whether and how a bridge can be built between qualitative and quantitative approaches for land-use planning work and to find out a way to overcome the gap that exists between the ability to construct computer simulation models to aid integrated land-use plan making and the demand for them by planning professionals. The study presented a theoretical framework of land-use planning based on scenario analysis (SA) method and multiagent system (MAS) simulation integration and selected freshwater wetlands in the Sanjiang Plain of China as a case study area. Study results showed that MAS simulation technique emphasizing quantitative process effectively compensated for the SA method emphasizing qualitative process, which realized the organic combination of qualitative and quantitative land-use planning work, and then provided a new idea and method for the land-use planning and sustainable managements of land resources. PMID:23818816

Ni, Shi-Jun; He, Zheng-Wei; Zhang, Cheng-Jiang; Zhang, Shu-Qing; Pan, Xin; Xia, Chao-Xu; Li, Xuan-Qiong

2013-01-01

262

Simulation Framework for Rapid Entry, Descent, and Landing (EDL) Analysis, Phase 2 Results  

NASA Technical Reports Server (NTRS)

The NASA Engineering and Safety Center (NESC) was requested to establish the Simulation Framework for Rapid Entry, Descent, and Landing (EDL) Analysis assessment, which involved development of an enhanced simulation architecture using the Program to Optimize Simulated Trajectories II simulation tool. The assessment was requested to enhance the capability of the Agency to provide rapid evaluation of EDL characteristics in systems analysis studies, preliminary design, mission development and execution, and time-critical assessments. Many of the new simulation framework capabilities were developed to support the Agency EDL-Systems Analysis (SA) team that is conducting studies of the technologies and architectures that are required to enable human and higher mass robotic missions to Mars. The findings, observations, and recommendations from the NESC are provided in this report.

Murri, Daniel G.

2011-01-01

263

Simulation Framework for Rapid Entry, Descent, and Landing (EDL) Analysis. Volume 1  

NASA Technical Reports Server (NTRS)

The NASA Engineering and Safety Center (NESC) was requested to establish the Simulation Framework for Rapid Entry, Descent, and Landing (EDL) Analysis assessment, which involved development of an enhanced simulation architecture using the Program to Optimize Simulated Trajectories II (POST2) simulation tool. The assessment was requested to enhance the capability of the Agency to provide rapid evaluation of EDL characteristics in systems analysis studies, preliminary design, mission development and execution, and time-critical assessments. Many of the new simulation framework capabilities were developed to support the Agency EDL Systems Analysis (EDL-SA) team, that is conducting studies of the technologies and architectures that are required to enable higher mass robotic and human mission to Mars. The findings of the assessment are contained in this report.

Murri, Daniel G.

2010-01-01

264

Air traffic control using a microwave landing system  

NASA Technical Reports Server (NTRS)

The performance of air traffic controllers using a simulated microwave landing system to control the landing of STOL aircraft is investigated. In a series of two experiments, controllers were asked to achieve a 60-sec separation between targets at the missed approach point when only two targets were on the simulated radar scope, and in the presence of 25 targets, with up to 10 on the screen at any one time. In both experiments, the presence of a ground wind is found to degrade separation performance, and an increased work load results in even greater separation variability, as the controllers did not have time to convert aircraft distances into times. In addition, curved courses are found to have an effect on performance. It is thus recommended that in order to create a practical air traffic control system with separation standards based on time, as in the MLS, controller work loads should be reduced and aircraft positions should be displayed with respect to time rather than distance.

Gershzohn, G.

1980-01-01

265

RAAG_A_288073 RAAG.cls January 23, 2008 19:32 Survival Analysis in Land Change Science  

E-print Network

) and remote sensing data, can effectively disclose relationships in land changes, and in many instances excel change modeling, remote sensing, survival analysis, temporal complexity. 10 15 L and change modeling has with geographic information systems (GIS) and remote sensing data, and to explore its potential to better

Brown, Daniel G.

266

Application of Calspan pitch rate control system to the Space Shuttle for approach and landing  

NASA Technical Reports Server (NTRS)

A pitch rate control system designed for use in the shuttle during approach and landing was analyzed and compared with a revised control system developed by NASA and the existing OFT control system. The design concept control system uses filtered pitch rate feedback with proportional plus integral paths in the forward loop. Control system parameters were designed as a function of flight configuration. Analysis included time and frequency domain techniques. Results indicate that both the Calspan and NASA systems significantly improve the flying qualities of the shuttle over the OFT. Better attitude and flight path control and less time delay are the primary reasons. The Calspan system is preferred because of reduced time delay and simpler mechanization. Further testing of the improved flight control systems in an in-flight simulator is recommended.

Weingarten, N. C.; Chalk, C. R.

1983-01-01

267

Design and reliability prediction of a distributed landing gear control system  

Microsoft Academic Search

Purpose – Proper function of landing gear plays a crucial role in the safe operation of an airplane. Traditional landing gear control system utilizes centralized control technology. The relatively heavy wire harness and low reliability accompanied with this technology make it logical to transfer from traditional control to real-time distributed control. This paper aims to look into a new landing

Lixuan Lu; Jianhe Lei

2010-01-01

268

Efficient Methods of Clutter Suppression for Coexisting Land and Weather Clutter Systems  

E-print Network

Efficient Methods of Clutter Suppression for Coexisting Land and Weather Clutter Systems The removal of coexisting land and weather clutter signals is a common problem in many radar applications. Although the optimal method for land-weather clutter suppression is known, it is usually not amenable

Candan, Cagatay

269

Drivers of land use change and household determinants of sustainability in smallholder farming systems of Eastern Uganda  

PubMed Central

Smallholder farming systems in sub-Saharan Africa have undergone changes in land use, productivity and sustainability. Understanding of the drivers that have led to changes in land use in these systems and factors that influence the systems’ sustainability is useful to guide appropriate targeting of intervention strategies for improvement. We studied low input Teso farming systems in eastern Uganda from 1960 to 2001 in a place-based analysis combined with a comparative analysis of similar low input systems in southern Mali. This study showed that policy-institutional factors next to population growth have driven land use changes in the Teso systems, and that nutrient balances of farm households are useful indicators to identify their sustainability. During the period of analysis, the fraction of land under cultivation increased from 46 to 78%, and communal grazing lands nearly completely disappeared. Cropping diversified over time; cassava overtook cotton and millet in importance, and rice emerged as an alternative cash crop. Impacts of political instability, such as the collapse of cotton marketing and land management institutions, of communal labour arrangements and aggravation of cattle rustling were linked to the changes. Crop productivity in the farming systems is poor and nutrient balances differed between farm types. Balances of N, P and K were all positive for larger farms (LF) that had more cattle and derived a larger proportion of their income from off-farm activities, whereas on the medium farms (MF), small farms with cattle (SF1) and without cattle (SF2) balances were mostly negative. Sustainability of the farming system is driven by livestock, crop production, labour and access to off-farm income. Building private public partnerships around market-oriented crops can be an entry point for encouraging investment in use of external nutrient inputs to boost productivity in such African farming systems. However, intervention strategies should recognise the diversity and heterogeneity between farms to ensure efficient use of these external inputs. PMID:20628448

de Ridder, Nico; de Jager, Andre; Delve, Robert J.; Bekunda, Mateete A.; Giller, Ken E.

2010-01-01

270

Analysis of Land Use/Land Cover Changes Using Remote Sensing Data and GIS at an Urban Area, Tirupati, India  

PubMed Central

Land use/land cover (LU/LC) changes were determined in an urban area, Tirupati, from 1976 to 2003 by using Geographical Information Systems (GISs) and remote sensing technology. These studies were employed by using the Survey of India topographic map 57 O/6 and the remote sensing data of LISS III and PAN of IRS ID of 2003. The study area was classified into eight categories on the basis of field study, geographical conditions, and remote sensing data. The comparison of LU/LC in 1976 and 2003 derived from toposheet and satellite imagery interpretation indicates that there is a significant increase in built-up area, open forest, plantation, and other lands. It is also noted that substantial amount of agriculture land, water spread area, and dense forest area vanished during the period of study which may be due to rapid urbanization of the study area. No mining activities were found in the study area in 1976, but a small addition of mining land was found in 2003. PMID:23781152

Mallupattu, Praveen Kumar; Sreenivasula Reddy, Jayarama Reddy

2013-01-01

271

AN ANALYSIS OF LAND DISTRIBUTION AND CONCENTRATION IN BOLIVIA  

Microsoft Academic Search

Despite the implementation of Bolivia's land reform in 1953, the agrarian structure continues to have an extreme concentration of land. Furthermore, in the last two decades regional agrarian structure have been aggravated by population pressures and a lack of new technological practices for most small scale farmers and peasants. Public and private institutions and urban residents observe hundreds of landless

Fernando Crespo Valdivia

1991-01-01

272

Land-Use Systems and Resilience of Tropical Rain Forests in the Tehuantepec Isthmus, Mexico  

Microsoft Academic Search

Land-cover types were analyzed for 1970, 1990 and 2000 as the bases for determining land-use systems and their influence on the resilience of tropical rain forests in the Tehuantepec Isthmus, Mexico. Deforestation (DR) and mean annual transformation rates were calculated from land-cover change data; thus, the classification of land-use change processes was determined according to their impact on resilience: a)

Arturo GarcÍa-Romero; Oralia Oropeza-Orozco; Leopoldo Galicia-Sarmiento

2004-01-01

273

A Summary of the Development of a Nominal Land Landing Airbag Impact Attenuation System for the Orion Crew Module  

NASA Technical Reports Server (NTRS)

Airborne Systems North America (formally Irvin Aerospace Inc) has developed an Airbag Landing System for the Orion Crew Module of the Crew Exploration Vehicle. This work is in support of the NASA Langley Research Center Landing System Advanced Development Project. Orion is part of the Constellation Program to send human explorers back to the moon, and then onwards to Mars and other destinations in the Solar System. A component of the Vision for Space Exploration, Orion is being developed to also enable access to space following the retirement of the Space Shuttle in the next decade. This paper documents the development of a conceptual design, fabrication of prototype assemblies, component level testing and two generations of airbag landing system testing. The airbag system has been designed and analyzed using the transient dynamic finite element code LS-DYNA(RegisteredTradeMark). The landing system consists of six airbag assemblies; each assembly comprising a primary impact venting airbag and a non-venting anti-bottoming airbag. The anti-bottoming airbag provides ground clearance following the initial impact attenuation sequence. Incorporated into each primary impact airbag is an active vent that allows the entrapped gas to exit the control volume. The size of the vent is tailored to control the flow-rate of the exiting gas. An internal shaping structure is utilized to control the shape of the primary or main airbags prior to ground impact; this significantly improves stroke efficiency and performance.

Tutt, Ben; Gill, Susannah; Wilson, Aaron; Johnson, Keith

2009-01-01

274

A mini/microcomputer-based land use information system  

NASA Technical Reports Server (NTRS)

The paper describes the Multipurpose Interactive NASA Information System (MINIS), a data management system for land-use applications. MINIS is written nearly entirely in FORTRAN IV, and has a full range of conditional, Boolean and arithmetic commands, as well as extensive format control and the capability of interactive file creation and updating. It requires a mini or microcomputer with at least 64 K of core or semiconductor memory. MINIS has its own equation-oriented query language for retrieval from different kinds of data bases. It features a graphics output which permits output of overlay maps. Some experience of the U.S. Department of Agriculture and the Tennessee State Planning Office with MINIS is discussed.

Seitz, R. N.; Keefer, R. L.; Britton, L. J.; Wilson, J. M.

1977-01-01

275

Land rigs benefit from portable top drive system  

SciTech Connect

A small, portable topdrive system, which can be installed in as little as 4 hr with little or no derrick modification, can help land rigs drill difficult or extended reach wells, according to Tesco Drilling Technology in Calgary. The units are designed for rigs that must be dismantled and moved after each well. To reduce the amount of derrick modifications, the systems are designed to fit on any rig that can make a conventional kelly connection with a 42-ft kelly and a 31-ft single. The compact unit can operate in tapered area above the monkey board. The first portable skid package went into the field in 1992. In its first 6 months of operation, this unit was installed on six rigs, drilled seven horizontal wells, and operated for about 2,000 hr with only 12.5 hr total downtime.

Not Available

1994-03-14

276

The NASA-Goddard Multi-Scale Modeling Framework - Land Information System: Global Land/atmosphere Interaction with Resolved Convection  

NASA Technical Reports Server (NTRS)

The present generation of general circulation models (GCM) use parameterized cumulus schemes and run at hydrostatic grid resolutions. To improve the representation of cloud-scale moist processes and landeatmosphere interactions, a global, Multi-scale Modeling Framework (MMF) coupled to the Land Information System (LIS) has been developed at NASA-Goddard Space Flight Center. The MMFeLIS has three components, a finite-volume (fv) GCM (Goddard Earth Observing System Ver. 4, GEOS-4), a 2D cloud-resolving model (Goddard Cumulus Ensemble, GCE), and the LIS, representing the large-scale atmospheric circulation, cloud processes, and land surface processes, respectively. The non-hydrostatic GCE model replaces the single-column cumulus parameterization of fvGCM. The model grid is composed of an array of fvGCM gridcells each with a series of embedded GCE models. A horizontal coupling strategy, GCE4fvGCM4Coupler4LIS, offered significant computational efficiency, with the scalability and I/O capabilities of LIS permitting landeatmosphere interactions at cloud-scale. Global simulations of 2007e2008 and comparisons to observations and reanalysis products were conducted. Using two different versions of the same land surface model but the same initial conditions, divergence in regional, synoptic-scale surface pressure patterns emerged within two weeks. The sensitivity of largescale circulations to land surface model physics revealed significant functional value to using a scalable, multi-model land surface modeling system in global weather and climate prediction.

Mohr, Karen Irene; Tao, Wei-Kuo; Chern, Jiun-Dar; Kumar, Sujay V.; Peters-Lidard, Christa D.

2013-01-01

277

Analysis of coastal change in Marie Byrd Land and Ellsworth Land, West Antarctica, using Landsat imagery  

USGS Publications Warehouse

The U.S. Geological Survey is using Landsat imagery from the early 1970s and mid- to late 1980s/early 1990s to analyze glaciological features, compile a glacier inventory, measure surface velocities of outlet glaciers, ice streams and ice shelves, determine coastline change and calculate the area and volume of iceberg calving in Antarctica. Ice-surface velocities in Marie Byrd and Ellsworth Lands, West Antarctica, range from the fast-moving Thwaites, Pine Island, Land and DeVicq Glaciers to the slower-moving ice shelves. The average ice-front velocity during the time interval of Landsat imagery, for the faster-moving outlet glaciers, was 2.9 km a-1 for Thwaites Glacier, 2.4 km a-1 for Pine Island Glacier, 2.0 km a-1 for Land Glacier and 1.4 km a-1 for DeVicq Glacier. Evaluation of coastal change from the early 1970s to the early 1990s shows advance of the floating ice front in some coastal areas and recession in others, with an overall small average advance in the entire coastal study area, but no major trend towards advance or retreat. Comparison of average ice-surface velocities with changes in the ice front has yielded estimates of iceberg calving. The total iceberg calving from the Marie Byrd Land and Ellsworth Land coasts during the study period was greater than 8500 km2 (estimated volume of about 2400 km3) or an average of about 550 km2 a-1 (more than 150 km3 a-1). Almost 70% of this discharge is contributed by Thwaites and Pine Island Glaciers.

Ferrigno, J.G.; Williams, R.S., Jr.; Rosanova, C.E.; Lucchitta, B.K.; Swithinbank, C.

1998-01-01

278

Land use and land cover classification, changes and analysis in gum Arabic belt in North Kordofan, Sudan  

NASA Astrophysics Data System (ADS)

The gum arabic belt in Sudan plays a significant role in environmental, social and economical aspects. This research was conducted in North Kordofan State, which is affected by modifications in conditions and composition of vegetation cover trends in the gum arabic belt as in the rest of the Sahelian Sudan zone. The objective of the paper is to study the classification, changes and analysis of the land use and land cover in the gum arabic belt in North Kordofan State in Sudan. The study used imageries from different satellites (Landsat and ASTER) and multi-temporal dates (MSS 1972, TM 1985, ETM+ 1999 and ASTER 2007) acquired in dry season. The imageries were geo-referenced and radiometrically corrected by using ENVI-FLAASH software. Image classification (pixel-based) and accuracy assessment were applied. Application of multi-temporal remote sensing data demonstrated successfully the identification and mapping of land use and land cover into five main classes. Forest dominated by Acacia senegal class was separated covering an area of 21% in the year 2007. The obvious changes and reciprocal conversions in the land use and land cover structure indicate the trends and conditions caused by the human interventions as well as ecological impacts on Acacia senegal trees. Also the study revealed that a drastic loss of forest resources occurred in the gum arabic belt in North Kordofan during 1972 to 2007 (25% for Acacia senegal trees). The study concluded that, using of traditional Acacia senegal-based agro-forestry as one of the most successful form in the gum belt.

Adam, Hassan E.; Csaplovics, Elmar; Elhaja, Mohamed E.; El Abbas, Mustafa M.

2013-10-01

279

Orion Crew Module Landing System Simulation and Verification  

NASA Technical Reports Server (NTRS)

NASA Langley Research Center (LaRC) has developed a comprehensive test and analysis program to evaluate the ability of LS-DYNA to model the materials and the phenomena involved in soil and water landing impacts of the Orion crew module. Elemental, scale boilerplate, and full-scale prototype testing is being conducted in support of the simulation verification and validation approach. Aspects of the simulations evaluated against test data include soil constitutive properties, water equations of state, and contact algorithms. Subsystems tested include airbags, crushable energy absorbing honeycomb materials, and energy absorbing seat support struts. The procedures, instrumentation, and general observations from each test series are presented. Plans for a series of swing tests of a full-scale boilerplate into a purpose-built water basin are described. Further plans for swing tests of flight-like prototypes into the water basin are noted.

Vassilakos, Gregory J.; Stegall, David E.; Hardy, Robin C.; Boitnott, Richard L.; Reaves, Mercedes; Mark, Stephen D.; Annett, Martin S.

2011-01-01

280

Modeling Land Ice in the Community Earth System Model  

NASA Astrophysics Data System (ADS)

Mass loss from glaciers and ice sheets is accelerating. In order to better understand and predict ice mass loss and resulting sea-level rise, we are coupling land-ice models to the Community Earth System Model (CESM). The current version of CESM includes the Glimmer Community Ice Sheet Model (Glimmer-CISM), which uses the shallow-ice approximation. We are now incorporating a new version of CISM with scalable, higher-order dynamical cores for improved simulations of fast ice flow. Also, we are implementing two-way coupling between ice sheets and the land and atmosphere. Here, we summarize results to dates and describe ongoing model development. We show that the simulated present-day surface mass balance of Greenland is in good agreement with observations and regional models, and we describe the sensitivity of the mass balance to climate changes. We show initial results from higher-order ice-sheet models with prescribed atmosphere and ocean forcing, including SeaRISE and ice2sea scenarios. Finally, we describe progress in coupling ice-sheet and ocean models (which will enable simulations with a dynamic Antarctic ice sheet) and in modeling smaller glaciers and ice caps.

Lipscomb, W.; Johnson, J.; Price, S.; Sacks, W.

2012-04-01

281

Assimilation of microwave brightness temperature in a land data assimilation system with multi-observation operators  

NASA Astrophysics Data System (ADS)

A radiative transfer model (RTM) that provides a link between model states and satellite observations (e.g., brightness temperature) can act as an observation operator in land data assimilation to directly assimilate brightness temperatures. In this study, a microwave Land Data Assimilation System (LDAS) was developed with three RTMs (The radiative transfer model for bare field (QH), land emissivity model (LandEM), and Community Microwave Emission Model (CMEM)) as its multi-observation operators (LDAS-MO). Assimilation experiments using the Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E) satellite brightness temperature data from July 2005 to December 2008 were then conducted to investigate the impact of the RTMs on the assimilated results over China. It was found that the assimilated volumetric soil-water content using each of the three observation operators improved the estimation of soil moisture content in the top soil layer (0-10 cm), with reduced root mean square errors (RMSEs), and increased correlation coefficients with field observations (OBS) as compared to a control run with no assimilation for the absence of frozen or snow-covered conditions. The assimilated soil moisture for the QH model, which was more sensitive to dry soil than the other models, produced closer correlations with OBS in arid and semi-arid regions while smaller RMSEs were observed for LandEM. CMEM agreed most closely with OBS over the middle and lower reaches of the Yangtze River due to its better simulation of the brightness temperature over densely vegetated areas. To improve assimilation accuracy, a Bayesian model averaging (BMA) scheme for the LDAS-MO was developed. The BMA scheme was found to significantly enhance assimilation capability producing the soil moisture analysis, showing the lowest RMSEs and highest correlations with OBS over all areas. It was demonstrated that the BMA scheme with LDAS-MO has the potential to estimate soil moisture with high accuracy.

Jia, Binghao; Tian, Xiangjun; Xie, Zhenghui; Liu, Jianguo; Shi, Chunxiang

2013-05-01

282

Surface Temperature Assimilation in the Global Land Data Assimilation System (GLDAS)  

NASA Technical Reports Server (NTRS)

The Global Land Data Assimilation System (GLDAS) is a global land parameterization that uses prescribed meteorology as forcing in order to determine regular gridded land surface states (temperature and moisture) and other properties (e.g. water and heat fluxes). In the present experiment, the assimilation of surface skin temperature is incorporated into the land parameterizations. The meteorological forcing was derived from the Goddard Earth Observing System (GEOS-3) Data Assimilation System (DAS) for the full year of 1998 GLDAS can use several land parameterizations, but here we use the Mosaic land surface model and the Common Land Model (CLM). TOVS surface temperature observations are assimilated into GLDAS. The TOVS observations are less frequent that observations used in previous experiments (ISCCP). The purpose of this presentation is to evaluate the impact of the TOVS assimilation on both Mosaic and CLM. We will especially consider the impact of coarse temporal observations on the assimilation and bias correction.

Bosilovich, Michael G.; Radakovich, Jon D.; daSilva, Arlindo; Houser, Paul R.; Atlas, Robert M. (Technical Monitor)

2002-01-01

283

Optimum recovery and landing systems for spacecraft and rocket booster stages  

Microsoft Academic Search

Various recovery and land landing systems for spacecraft, including non-steerable aerodynamic decelerators (parachutes, ballute, and paraballute), steerable aerodynamic decelerators, deployable flexible wings, and lifting-body and winged vehicles, are considered. Materials used, design and performance characteristics, and deployment techniques are described. Non-steerable decelerators are applicable to vertical descent modes. The Space Shuttle booster recovery system and Viking Mars landing system both

K. O. Brauer

1974-01-01

284

Detection of land use/land cover changes through the comparative analysis of NDVI-MODIS phenological clusters  

NASA Astrophysics Data System (ADS)

The use of satellite time series provides precious information to understand vegetation dynamics. In particular, they can be profitably used for studying magnitudo and spatial extent of the Earth's land cover alterations, which affect directly biodiversity, can contribute to land degradation, and are linked to climate change by feedback mechanisms. In the framework of PRO-LAND project (PO-FESR Basilicata 2007-2013), we used NDVI-MODIS satellite time series (250 m), available as 16-day composite from the NASA LPDAAC dataset, to analyze land cover changes occurred in Basilicata region (Southern Italy) during the period 2000-2010. We performed a phenological clustering for the years 2000 and 2010 by means of the unsupervised classification fuzzy k-means which is able to identify gradual differences among phenological patterns. The time domain considered is from April to October in order to reduce disturbances due to the presence of clouds, which can distort actual vegetation phenological profiles. The optimal number of clusters to capture the heterogeneity of the examined area was fixed at ten, because it seemed to be a good trade-off between the need of an efficient representation of ecosystems and the ability to detect local fragmentation effects. Results show that the temporal patterns of the ten clusters can be organised in a continuum of phenological curves. They can be sorted unambiguously according to increasing percentage of man-made areas (decreasing percentage of natural areas) and allow us to well discriminate different land cover compositions by looking not only at differences in mean NDVI values but also at differences in the seasonal timing. The cluster sequence for both the examined years mostly follows the spatial arrangement of the land cover classes, and the complex orography of the investigated region. In general, results show that a slight variability characterize the arrangement of cluster cores, particularly for the clusters with a dominance of natural or anthropic covers, whereas a slightly higher variability appears at the cluster borders (especially for clusters where anthropic and natural covers are mixed). Overall, this study puts into evidence a fair decrease in the number of patches (~ -10%) accompanied by the increase of the mean patch area (~ +10%), which means that there is a tendency to compaction of the areas that are classified in the same phenological cluster. This phenomenon is particularly interesting for mountainous natural areas. A coupled analysis of meteo-climatic conditions and implemented land cover management policies can enable to identify the causes behind the observed phenomena, allowing for a more complete picture and a better interpretation of the occurred land cover changes.

Simoniello, Tiziana; Imbrenda, Vito; Lanfredi, Maria

2013-04-01

285

Numerical Analysis of Steady Flow around a Landing Gear Noise Measurement Model  

NASA Astrophysics Data System (ADS)

It is well known that landing-gear noise is one of the dominant noise sources during the approach phase of a civil airplane. Therefore, it is important to understand the noise generation mechanism and reduce the noise from a landing gear. In this study, steady-state flow analysis around a landing gear model is reported using unstructured-mesh method. To predict the landing gear noise directly, unsteady flow analysis is necessary. However, even from the steady-state analysis, information related with the noise generation could be gained by focusing on the accelerated region or wake interference. From these preliminary results, basic flow field information is obtained to understand the flow physics around the complicated landing gear geometry.

Imamura, Taro; Hirai, Tohru; Yokokawa, Yuzuru; Murayama, Mitsuhiro; Yamamoto, Kazuomi

286

Elemental analysis in environmental land samples by stand-off laser-induced breakdown spectroscopy  

NASA Astrophysics Data System (ADS)

The stand-off detection and analysis of environmental land samples have been demonstrated using laser-induced breakdown spectrometry. The samples of interest have included soils and vegetation powder. Elements Hg, As, Pb, Zn, Cd and Cr have been spectrally analysed with a focus on Hg as a trace contaminant in the samples. It is found that element Fe, usually contained in land samples, is a main source of spectral interference for Hg detection due to its ever present iron emission line at 253.68 nm that is closely adjacent to the strongest Hg emission line at 253.65 nm, and hence, a high resolution of spectral detection is necessary. The strong spectral signals from Bremsstrahlung emission in laser-induced plasma and atomic emission of Fe of high concentration caused a significant reduction in detection resolution in the use of image intensifier of an ICCD. The limit of detection at ~8 ppm for Hg detection in soil samples with iron as a minor constituent has been achieved, using an optical chopper and a CCD detector for laser-induced breakdown spectroscopy (LIBS) signal detection. Such detection method in LIBS system has shown a great advantage in determining trace elements from interfering elemental constituents in land sample matrixes.

Fang, Xiao; Ahmad, S. R.

2014-06-01

287

Green Infrastructure & Sustainable Urban Land Use Decision Analysis Workshop  

EPA Science Inventory

Introduce green infrastructure, concepts and land use alternatives, to City of Cleveland operations staff. Discuss potential of green alternatives to impact daily operations and routine maintenance activities. Tie in sustainability concepts to long-term City planning and discu...

288

Manifesting Destiny: A Land Education Analysis of Settler Colonialism in Jamestown, Virginia, USA  

ERIC Educational Resources Information Center

Globally, colonization has been and continues to be enacted in the take-over of Indigenous land and the subsequent conversion of agriculture from diverse food and useful crops to large-scale monoculture and cash crops. This article uses a land education analysis to map the rise of the ideology and practices of Manifest Destiny in Virginia.…

McCoy, Kate

2014-01-01

289

GIS-based quality analysis on the cultivated land resources in poor areas of China  

NASA Astrophysics Data System (ADS)

Cultivated land resource is a key factor that affects the development standard of a region. By analysis of land use and land cover data in 2000, together with national geographical data, soil fertility comprehensive quality assessment data (1980), a GIS-based research is carried out on the quality analysis of cultivated land resources in poor areas. Firstly, data mining methods are used to gather the inter-relationships between the poor areas' cultivated land resources and its geographical background factors. Secondly, comparative analysis between the poor areas and non-poor areas is conducted to reveal the difference. Results show that the big difference exists in the basic natural features of the cultivated land resources between poor and non-poor areas. Although the quantity of cultivated land resource in those poor areas is not less than that of non-poor areas, the quality is lowly evaluated because of its high elevation, steep slope and earth surface roughness. Finally, after overlay analysis, the natural quality of cultivated land resources in poor areas is assessed according to their topographical and soil fertility features.

Liu, Ling; Wang, Ying Jie; Han, Jia Fu

2009-07-01

290

Spatial Analysis of Residential Land Prices in Belgium: Accessibility, Linguistic Border, and Environmental Amenities  

Microsoft Academic Search

Goffette-Nagot F., Reginster I. and Thomas I. Spatial analysis of residential land prices in Belgium: accessibility, linguistic border, and environmental amenities, Regional Studies. This paper explores the spatial variation of land prices in Belgium. The originality of the methodology is threefold: to work at the spatial extent of an entire country; to compute accessibility measures to all jobs and several

Florence Goffette-Nagot; Isabelle Reginster; Isabelle Thomas

2010-01-01

291

Land disposal of water treatment plant sludge -- A feasibility analysis  

SciTech Connect

In this study, the following alternative disposal methods for the Buffalo Pound Water Treatment Sludge were evaluated: landfilling, discharge into sanitary sewers, long-term lagooning, use in manufacturing, co-composting, alum recovery and land application. Land application was chosen at the best disposal alternative. Preliminary design resulted in a 1% dry alum sludge loading rate (25 tonnes/ha), requiring 35 ha over a nine-year period and a phosphorus fertilizer supplement of about 50kg/ha.

Viraraghavan, T.; Multon, L.M.; Wasylenchuk, E.J.

1998-07-01

292

Results from Assimilating AMSR-E Soil Moisture Estimates into a Land Surface Model Using an Ensemble Kalman Filter in the Land Information System  

NASA Technical Reports Server (NTRS)

Improve simulations of soil moisture/temperature, and consequently boundary layer states and processes, by assimilating AMSR-E soil moisture estimates into a coupled land surface-mesoscale model Provide a new land surface model as an option in the Land Information System (LIS)

Blankenship, Clay B.; Crosson, William L.; Case, Jonathan L.; Hale, Robert

2010-01-01

293

Architecture of the global land acquisition system: applying the tools of network science to identify key vulnerabilities  

NASA Astrophysics Data System (ADS)

Global land acquisitions, often dubbed ‘land grabbing’ are increasingly becoming drivers of land change. We use the tools of network science to describe the connectivity of the global acquisition system. We find that 126 countries participate in this form of global land trade. Importers are concentrated in the Global North, the emerging economies of Asia, and the Middle East, while exporters are confined to the Global South and Eastern Europe. A small handful of countries account for the majority of land acquisitions (particularly China, the UK, and the US), the cumulative distribution of which is best described by a power law. We also find that countries with many land trading partners play a disproportionately central role in providing connectivity across the network with the shortest trading path between any two countries traversing either China, the US, or the UK over a third of the time. The land acquisition network is characterized by very few trading cliques and therefore characterized by a low degree of preferential trading or regionalization. We also show that countries with many export partners trade land with countries with few import partners, and vice versa, meaning that less developed countries have a large array of export partnerships with developed countries, but very few import partnerships (dissassortative relationship). Finally, we find that the structure of the network is potentially prone to propagating crises (e.g., if importing countries become dependent on crops exported from their land trading partners). This network analysis approach can be used to quantitatively analyze and understand telecoupled systems as well as to anticipate and diagnose the potential effects of telecoupling.

Seaquist, J. W.; Li Johansson, Emma; Nicholas, Kimberly A.

2014-11-01

294

77 FR 8895 - Public Land Order No. 7788; Withdrawal of National Forest System Land for the Red Cloud...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Withdrawal of National Forest System Land for the Red Cloud Campground; New Mexico AGENCY: Bureau...historical interpretive integrity of the Red Cloud Campground within the Cibola National...capital investment expended to develop the Red Cloud Campground facility and the...

2012-02-15

295

78 FR 58555 - Public Land Order No. 7821; Withdrawal of National Forest System Land for Steamboat Rock Picnic...  

Federal Register 2010, 2011, 2012, 2013, 2014

This order withdraws on behalf of the United States Forest Service, 50 acres of National Forest System land from location and entry under the United States mining laws for a period of 20 years to protect the recreational uses and improvements at the Steamboat Rock Picnic Grounds within the Black Hills National Forest in South...

2013-09-24

296

Using GIS and outranking multicriteria analysis for land-use suitability assessment  

Microsoft Academic Search

Land-useplanners oftenmake complexdecisionswithin a shortperiod of time when they must take into account sustainable developmentand economic competitiveness. A set of land-use suitability maps would be very useful in this respect.Ideally, thesemapsshouldincorporatecomplexcriteriaintegratingseveral stakeholders' points of view. To illustrate the feasibility of this approach, a land suitability map for housing was realised for a small region of Switzerland. Geographical Information System technology

Florent Joerin; Marius Thériault; André Musy

2001-01-01

297

An Onboard Monocular Vision System for Autonomous Takeoff, Hovering and Landing of a Micro Aerial Vehicle  

E-print Network

An Onboard Monocular Vision System for Autonomous Takeoff, Hovering and Landing of a Micro Aerial monocular vision system for autonomous takeoff, hovering and landing of a Micro Aerial Vehicle (MAV). Since for environment perception and are usually lightweight. Thus, many UAVs rely on vision systems for autonomous

Zell, Andreas

298

Some findings on the applications of ERTS and Skylab imagery for metropolitan land use analysis  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. Work undertaken on a three-sensor land use data evaluation for a portion of the Phoenix area is reported. Analyses between land use data generated from 1970 high altitude photography and that detectable from ERTS and Skylab, especially in terms of changes in land use indicate that ERTS and Skylab imagery can be used effectively to detect and identify areas of post-1970 land use change, especially those documenting urban expansion at the rural-urban fringe. Significant preliminary findings on the utility of ERTS and Skylab data for metropolitan land use analysis, substantiated by evaluation with 1970 and 1972 ground control land use data are reported.

Alexander, R. H. (principal investigator); Milazzo, V. A.

1974-01-01

299

Research priorities in land use and land-cover change for the Earth system and integrated assessment modelling  

E-print Network

to contemporary time. Given the inherent uncertainty in human systems, in IAMs all kinds of assumptions on future development of factors related to land use such as socio-economic, energy and demo- graphic processes are made. These assumptions are partly based... recognizes the importance of land use as a critical factor in socio-economic decision making, e.g. for food and timber production, valuation of the state of ecosystems and their services, and increas- ingly, as a response to demand for biofuels...

Hibbard, Kathy; Janetos, Anthony; van Vuuren, Detlef P.; Pongtatz, Julia; Rose, Steven K.; Betts, Richard; Herold, Martin; Feddema, Johannes J.

2010-01-01

300

An equilibrium analysis of the land use structure in the Yunnan Province, China  

NASA Astrophysics Data System (ADS)

Global land use structure is changing rapidly due to unceasing population growth and accelerated urbanization, which leads to fierce competition between the rigid demand for built-up area and the protection of cultivated land, forest, and grassland. It has been a great challenge to realize the sustainable development of land resources. Based on a computable general equilibrium model of land use change with a social accounting matrix dataset, this study implemented an equilibrium analysis of the land use structure in the Yunnan Province during the period of 2008-2020 under three scenarios, the baseline scenario, low TFP (total factor productivity) scenario, and high TFP scenario. The results indicated that under all three scenarios, area of cultivated land declined significantly along with a remarkable expansion of built-up area, while areas of forest, grassland, and unused land increased slightly. The growth rate of TFP had first negative and then positive effects on the expansion of built-up area and decline of cultivated land as it increased. Moreover, the simulated changes of both cultivated land and built-up area were the biggest under the low TFP scenario, and far exceeded the limit in the Overall Plan for Land Utilization in the Yunnan Province in 2020. The scenario-based simulation results are of important reference value for policy-makers in making land use decisions, balancing the fierce competition between the protection of cultivated land and the increasing demand for built-up area, and guaranteeing food security, ecological security, and the sustainable development of land resources.

van Aken, H. M.; van Veldhoven, A. K.; Veth, C.; de Ruijter, W. P. M.; van Leeuwen, P. J.; Drijfhout, S. S.; Whittle, C. P.; Rouault, M.

2014-06-01

301

An equilibrium analysis of the land use structure in the Yunnan Province, China  

NASA Astrophysics Data System (ADS)

Global land use structure is changing rapidly due to unceasing population growth and accelerated urbanization, which leads to fierce competition between the rigid demand for built-up area and the protection of cultivated land, forest, and grassland. It has been a great challenge to realize the sustainable development of land resources. Based on a computable general equilibrium model of land use change with a social accounting matrix dataset, this study implemented an equilibrium analysis of the land use structure in the Yunnan Province during the period of 2008-2020 under three scenarios, the baseline scenario, low TFP (total factor productivity) scenario, and high TFP scenario. The results indicated that under all three scenarios, area of cultivated land declined significantly along with a remarkable expansion of built-up area, while areas of forest, grassland, and unused land increased slightly. The growth rate of TFP had first negative and then positive effects on the expansion of built-up area and decline of cultivated land as it increased. Moreover, the simulated changes of both cultivated land and built-up area were the biggest under the low TFP scenario, and far exceeded the limit in the Overall Plan for Land Utilization in the Yunnan Province in 2020. The scenario-based simulation results are of important reference value for policy-makers in making land use decisions, balancing the fierce competition between the protection of cultivated land and the increasing demand for built-up area, and guaranteeing food security, ecological security, and the sustainable development of land resources.

Luo, Jiao; Zhan, Jinyan; Lin, Yingzhi; Zhao, Chunhong

2014-09-01

302

Short-rotation wood production systems for marginal land in the Great Lakes region: Final report  

Microsoft Academic Search

Over the long-term, short-rotation wood production systems can provide a sustained supply of wood as a renewable energy resource. Short-rotation forestry is an alternative to conventional agriculture on marginal land. Since several harvests occur from a single planting, short rotation systems provide relatively permanent vegetation. The potential for improved land use and resource conservation exists in conversion of marginal land

Majerus

1986-01-01

303

Flight test evaluation of the Stanford University/United Airlines differential GPS Category 3 automatic landing system  

NASA Technical Reports Server (NTRS)

Test flights were conducted to evaluate the capability of Differential Global Positioning System (DGPS) to provide the accuracy and integrity required for International Civil Aviation Organization (ICAO) Category (CAT) 3 precision approach and landings. These test flights were part of a Federal Aviation Administration (FAA) program to evaluate the technical feasibility of using DGPS based technology for CAT 3 precision approach and landing applications. A United Airlines Boeing 737-300 (N304UA) was equipped with DGPS receiving equipment and additional computing capability provided by Stanford University. The test flights were conducted at NASA Ames Research Center's Crows Landing Flight Facility, Crows Landing, California. The flight test evaluation was based on completing 100 approaches and autolandings; 90 touch and go, and 10 terminating with a full stop. Two types of accuracy requirements were evaluated: 1) Total system error, based on the Required Navigation Performance (RNP), and 2) Navigation sensor error, based on ICAO requirements for the Microwave Landing System (MLS). All of the approaches and autolandings were evaluated against ground truth reference data provided by a laser tracker. Analysis of these approaches and autolandings shows that the Stanford University/United Airlines system met the requirements for a successful approach and autolanding 98 out of 100 approaches and autolandings, based on the total system error requirements as specified in the FAA CAT 3 Level 2 Flight Test Plan.

Kaufmann, David N.; Ncnally, B. David

1995-01-01

304

Land Application of Wastes: An Educational Program. Costing Land Application Systems - Module 10.  

ERIC Educational Resources Information Center

This module expands on the concepts of cost estimation and comparison of costs among various treatment alternatives which were presented in a previous module. The need for useful published cost data is stressed. Criteria for selecting cost references are presented, and examples of charts and graphs from several of these are used in comparing land

Clarkson, W. W.; And Others

305

The economic potential of bioenergy for climate change mitigation with special attention given to implications for the land system  

NASA Astrophysics Data System (ADS)

Biomass from cellulosic bioenergy crops is expected to play a substantial role in future energy systems, especially if climate policy aims at stabilizing greenhouse gas concentration at low levels. However, the potential of bioenergy for climate change mitigation remains unclear due to large uncertainties about future agricultural yield improvements and land availability for biomass plantations. This letter, by applying a modelling framework with detailed economic representation of the land and energy sector, explores the cost-effective contribution of bioenergy to a low-carbon transition, paying special attention to implications for the land system. In this modelling framework, bioenergy competes directly with other energy technology options on the basis of costs, including implicit costs due to biophysical constraints on land and water availability. As a result, we find that bioenergy from specialized grassy and woody bioenergy crops, such as Miscanthus or poplar, can contribute approximately 100 EJ in 2055 and up to 300 EJ of primary energy in 2095. Protecting natural forests decreases biomass availability for energy production in the medium, but not in the long run. Reducing the land available for agricultural use can partially be compensated for by means of higher rates of technological change in agriculture. In addition, our trade-off analysis indicates that forest protection combined with large-scale cultivation of dedicated bioenergy is likely to affect bioenergy potentials, but also to increase global food prices and increase water scarcity. Therefore, integrated policies for energy, land use and water management are needed.

Popp, Alexander; Dietrich, Jan Philipp; Lotze-Campen, Hermann; Klein, David; Bauer, Nico; Krause, Michael; Beringer, Tim; Gerten, Dieter; Edenhofer, Ottmar

2011-07-01

306

Information Processing Analysis of Human Land Mine Detection Skill James J. Staszewski1  

E-print Network

Mellon Research Institute and Dept. of Psychology, Carnegie Mellon University ABSTRACT This paper concluded that "human operators perform better with any detector system than the corresponding fully welfare of civilians in lands in which armed conflicts occur. From a military perspective, land mines have

Creswell, J. David

307

Effects of Urban Land Supply Policy on Real Estate in China: An Econometric Analysis  

Microsoft Academic Search

Since 2005, the Chinese government has frequently strengthened controls on the real estate market. Land supply policy was included in the system of state macro-control on the real estate market and state economic development. This paper examines the following issues after analyzing the panel data of Yunnan Province and other provinces of China. (1) Does land supply have significant effects

Hong Zhang

308

Anticipating Forest and Range Land Development in Central Oregon (USA) for Landscape Analysis, with an Example Application Involving Mule Deer  

NASA Astrophysics Data System (ADS)

Forest policymakers, public lands managers, and scientists in the Pacific Northwest (USA) seek ways to evaluate the landscape-level effects of policies and management through the multidisciplinary development and application of spatially explicit methods and models. The Interagency Mapping and Analysis Project (IMAP) is an ongoing effort to generate landscape-wide vegetation data and models to evaluate the integrated effects of disturbances and management activities on natural resource conditions in Oregon and Washington (USA). In this initial analysis, we characterized the spatial distribution of forest and range land development in a four-county pilot study region in central Oregon. The empirical model describes the spatial distribution of buildings and new building construction as a function of population growth, existing development, topography, land-use zoning, and other factors. We used the model to create geographic information system maps of likely future development based on human population projections to inform complementary landscape analyses underway involving vegetation, habitat, and wildfire interactions. In an example application, we use the model and resulting maps to show the potential impacts of future forest and range land development on mule deer ( Odocoileus hemionus) winter range. Results indicate significant development encroachment and habitat loss already in 2000 with development located along key migration routes and increasing through the projection period to 2040. The example application illustrates a simple way for policymakers and public lands managers to combine existing data and preliminary model outputs to begin to consider the potential effects of development on future landscape conditions.

Kline, Jeffrey D.; Moses, Alissa; Burcsu, Theresa

2010-05-01

309

Anticipating forest and range land development in central Oregon (USA) for landscape analysis, with an example application involving mule deer.  

PubMed

Forest policymakers, public lands managers, and scientists in the Pacific Northwest (USA) seek ways to evaluate the landscape-level effects of policies and management through the multidisciplinary development and application of spatially explicit methods and models. The Interagency Mapping and Analysis Project (IMAP) is an ongoing effort to generate landscape-wide vegetation data and models to evaluate the integrated effects of disturbances and management activities on natural resource conditions in Oregon and Washington (USA). In this initial analysis, we characterized the spatial distribution of forest and range land development in a four-county pilot study region in central Oregon. The empirical model describes the spatial distribution of buildings and new building construction as a function of population growth, existing development, topography, land-use zoning, and other factors. We used the model to create geographic information system maps of likely future development based on human population projections to inform complementary landscape analyses underway involving vegetation, habitat, and wildfire interactions. In an example application, we use the model and resulting maps to show the potential impacts of future forest and range land development on mule deer (Odocoileus hemionus) winter range. Results indicate significant development encroachment and habitat loss already in 2000 with development located along key migration routes and increasing through the projection period to 2040. The example application illustrates a simple way for policymakers and public lands managers to combine existing data and preliminary model outputs to begin to consider the potential effects of development on future landscape conditions. PMID:20300934

Kline, Jeffrey D; Moses, Alissa; Burcsu, Theresa

2010-05-01

310

Integrated dynamic landscape analysis and modeling system (IDLAMS) : installation manual.  

SciTech Connect

The Integrated Dynamic Landscape Analysis and Modeling System (IDLAMS) is a prototype, integrated land management technology developed through a joint effort between Argonne National Laboratory (ANL) and the US Army Corps of Engineers Construction Engineering Research Laboratories (USACERL). Dr. Ronald C. Sundell, Ms. Pamela J. Sydelko, and Ms. Kimberly A. Majerus were the principal investigators (PIs) for this project. Dr. Zhian Li was the primary software developer. Dr. Jeffrey M. Keisler, Mr. Christopher M. Klaus, and Mr. Michael C. Vogt developed the decision analysis component of this project. It was developed with funding support from the Strategic Environmental Research and Development Program (SERDP), a land/environmental stewardship research program with participation from the US Department of Defense (DoD), the US Department of Energy (DOE), and the US Environmental Protection Agency (EPA). IDLAMS predicts land conditions (e.g., vegetation, wildlife habitats, and erosion status) by simulating changes in military land ecosystems for given training intensities and land management practices. It can be used by military land managers to help predict the future ecological condition for a given land use based on land management scenarios of various levels of training intensity. It also can be used as a tool to help land managers compare different land management practices and further determine a set of land management activities and prescriptions that best suit the needs of a specific military installation.

Li, Z.; Majerus, K. A.; Sundell, R. C.; Sydelko, P. J.; Vogt, M. C.

1999-02-24

311

Exploitation of GeoEye-1 Data for Land Use/Land Cover Analysis Using Object-Based Image Analysis in the Eastern Nile Basin of Sudan  

NASA Astrophysics Data System (ADS)

Recently, object-oriented classification techniques based on image segmentation approaches are being studied using high-resolution satellite images to extract various thematic information. In this study different types of land use/land cover (LULC) types were analysed by employing object-based image analysis approach to GeoEye-1 data at the Eastern Nile Basin of Sudan. For that purpose, multi-resolution segmentation (MRS) of the Definiens software was used for creating the image objects. Using the feature space optimisation (FSO) tool the attributes of the GeoEye-1 image were optimised in order to obtain the best separability among classes for the LULC mapping. The best separation distance of the tested spectral, shape and textural features showed different variations among the discriminated LULC classes. An overall accuracy of 94 % with a kappa value 0.92 was resulted from the classification scheme, while accuracy differences among the classes were kept minimal. Finally, the results highlighted the importance of using very high-resolution satellite images for delineating the complex land use cover in the dry lands of the Eastern Nile Basin. Key Words: Multi-resolution segmentation; feature space optimisation; land use/land cover mapping; Eastern Nile Basin

Guma Biro Turk, Khalid; Pradhan, Biswajeet

312

Cross-Site Comparison of Land-Use Decision-Making and Its Consequences across Land Systems with a Generalized Agent-Based Model  

PubMed Central

Local changes in land use result from the decisions and actions of land-users within land systems, which are structured by local and global environmental, economic, political, and cultural contexts. Such cross-scale causation presents a major challenge for developing a general understanding of how local decision-making shapes land-use changes at the global scale. This paper implements a generalized agent-based model (ABM) as a virtual laboratory to explore how global and local processes influence the land-use and livelihood decisions of local land-users, operationalized as settlement-level agents, across the landscapes of six real-world test sites. Test sites were chosen in USA, Laos, and China to capture globally-significant variation in population density, market influence, and environmental conditions, with land systems ranging from swidden to commercial agriculture. Publicly available global data were integrated into the ABM to model cross-scale effects of economic globalization on local land-use decisions. A suite of statistics was developed to assess the accuracy of model-predicted land-use outcomes relative to observed and random (i.e. null model) landscapes. At four of six sites, where environmental and demographic forces were important constraints on land-use choices, modeled land-use outcomes were more similar to those observed across sites than the null model. At the two sites in which market forces significantly influenced land-use and livelihood decisions, the model was a poorer predictor of land-use outcomes than the null model. Model successes and failures in simulating real-world land-use patterns enabled the testing of hypotheses on land-use decision-making and yielded insights on the importance of missing mechanisms. The virtual laboratory approach provides a practical framework for systematic improvement of both theory and predictive skill in land change science based on a continual process of experimentation and model enhancement. PMID:24489696

Magliocca, Nicholas R.; Brown, Daniel G.; Ellis, Erle C.

2014-01-01

313

A land use and environmental impact analysis of the Norfolk-Portsmouth SMSA  

NASA Technical Reports Server (NTRS)

The feasibility of using remote sensing techniques for land use and environmental assessment in the Norfolk-Portsmouth area is discussed. Data cover the use of high altitude aircraft and satellite remote sensing data for: (1) identifying various heirarchial levels of land use, (2) monitoring land use changes for repetitive basis, (3) assessing the impact of competing land uses, and (4) identifying areas of potential environmental deterioration. High altitude aircraft photographs (scale 1:120,000) acquired in 1959, 1970, and 1972, plus Earth Resources Technology Satellite (ERTS-1) color composite images acquired in 1972 were used for the land use and environmental assessments. The high altitude aircraft photography, as expected, was successfully used to map Level 1, Level 2, as well as some urban Level 3 land use categories. However, the detail of land use analysis obtainable from the ERTS imagery exceeded the expectations for the U.S. Geological Survey's land use classification scheme. Study results are consistent with the initial investigation which determined Level 1 land use change to be 16.7 square km per year.

Mitchel, W. B.; Berlin, G. L.

1973-01-01

314

Application of spatial features to satellite land-use analysis. [spectral signature variations  

NASA Technical Reports Server (NTRS)

A Level I land-use analysis of selected training areas of the Colorado Front Range was carried out using digital ERTS-A satellite imagery. Level I land-use categories included urban, agriculture (irrigated and dryland farming), rangeland, and forests. The spatial variations in spectral response for these land-use classes were analyzed using discrete two-dimensional Fourier transforms to isolate and extract spatial features. Analysis was performed on ERTS frame 1352-17134 (July 10, 1973) and frame number 1388-17131 (August 15, 1973). On training sets, spatial features yielded 80 to 100 percent classification accuracies with commission errors ranging from 0 to 20 percent.

Smith, J.; Hornung, R.; Berry, J.

1975-01-01

315

Experimental and analytical studies of advanced air cushion landing systems  

NASA Technical Reports Server (NTRS)

Several concepts are developed for air cushion landing systems (ACLS) which have the potential for improving performance characteristics (roll stiffness, heave damping, and trunk flutter), and reducing fabrication cost and complexity. After an initial screening, the following five concepts were evaluated in detail: damped trunk, filled trunk, compartmented trunk, segmented trunk, and roll feedback control. The evaluation was based on tests performed on scale models. An ACLS dynamic simulation developed earlier is updated so that it can be used to predict the performance of full-scale ACLS incorporating these refinements. The simulation was validated through scale-model tests. A full-scale ACLS based on the segmented trunk concept was fabricated and installed on the NASA ACLS test vehicle, where it is used to support advanced system development. A geometrically-scaled model (one third full scale) of the NASA test vehicle was fabricated and tested. This model, evaluated by means of a series of static and dynamic tests, is used to investigate scaling relationships between reduced and full-scale models. The analytical model developed earlier is applied to simulate both the one third scale and the full scale response.

Lee, E. G. S.; Boghani, A. B.; Captain, K. M.; Rutishauser, H. J.; Farley, H. L.; Fish, R. B.; Jeffcoat, R. L.

1981-01-01

316

A role for AVIRIS in the Landsat and Advanced Land Remote Sensing Systems program  

NASA Technical Reports Server (NTRS)

As a calibrated imaging spectrometer flying at a 20 km altitude, AVIRIS may contribute to the Landsat and the Advanced Land Remote Sensing System efforts. These contributions come in the areas of: (1) on-orbit calibration, (2) specification of new spectral bands, (3) validation of algorithms, and (4) investigation of an imaging spectrometer of the Advanced Land Remote Sensing System.

Green, Robert O.; Simmonds, John J.

1993-01-01

317

A Terminal Descent Sensor Trade Study Overview for the Orion Landing and Recovery System  

NASA Technical Reports Server (NTRS)

This trade study was conducted as a part of the Orion Landing System Advanced Development Project to determine possible Terminal Descent Sensor (TDS) architectures that could be used for a rocket assisted landing system. Several technologies were considered for the Orion TDS including radar, lidar, GPS applications, mechanical sensors, and gamma ray altimetry.

Dunn, Catherine; Prakash, Ravi

2008-01-01

318

A Method to Reduce the Need for Large Antennas in Microwave Landing Systems (MLS)  

Microsoft Academic Search

The replacement of the present Instrument Landing System (ILS) by the new Microwave Landing System (MLS) which is supposed to begin about 1980 is caused by increasing requirements for capacity, accuracy and coverage which ILS cannot meet. The increased accuracy is largely achieved by the use of microwave frequencies which implies larger antennas in wavelengths in spite of reduced physical

B. Forssell

1976-01-01

319

Participatory modeling of endangered wildlife systems: Simulating the sage-grouse and land use in  

E-print Network

METHODS Participatory modeling of endangered wildlife systems: Simulating the sage-grouse and land 2008 The Greater sage-grouse (Centrocercus urophasianus) occupies the sage brush habitats of Western for system dynamics to synthesize known sage-grouse dynamics and local land use patterns to support

Ford, Andrew

320

IMPLEMENTATION AND APPLICATION OF THE KALMAN FILTER DATA ASSIMILATION APPROACHES IN NASA'S LAND INFORMATION SYSTEM INFRASTRUCTURE  

Technology Transfer Automated Retrieval System (TEKTRAN)

Building on the North-American and Global Land Data Assimilation Systems (LDAS), a Land Information System (LIS) infrastructure has been developed at NASA Goddard Space Flight Center jointly with NOAA-NCEP, NWS and university collaborators. In the context of numerical weather prediction applications...

321

Land Resource Sustainability for Urban Development: Spatial Decision Support System Prototype  

Microsoft Academic Search

Land resource sustainability for urban development characterizes the problem of decision-making with multiplicity and uncertainty. A decision support system prototype aids in the assessment of incremental land development plan proposals put forth within the long-term community priority of a sustainable growth. Facilitating this assessment is the analytic hierarchy process (AHP), a multicriteria evaluation and decision support system. The decision support

Reza Banai

2005-01-01

322

Modular Building Blocks for Manned Spacecraft: A Case Study for Moon and Mars Landing Systems  

E-print Network

Modular Building Blocks for Manned Spacecraft: A Case Study for Moon and Mars Landing Systems modular building blocks for platforming of manned Moon and Mars landing systems employing modularity. The motivation for platforming is the need to reduce overall Moon and Mars exploration architecture lifecycle

de Weck, Olivier L.

323

A Generic, Interoperable, Hydrologic Data Assimilation Framework using the Land Information System  

Technology Transfer Automated Retrieval System (TEKTRAN)

Land Information System (LIS; http://lis.gsfc.nasa.gov) is a hydrologic modeling system that integrates the use of various community land surface models, use of ground and satellite-based observations, and high performance computing and data management tools to enable hydrologic prediction at variou...

324

LUBBOCK LAND TREATMENT SYSTEM RESEARCH AND DEMONSTRATION PROJECT. VOLUME 1. DEMONSTRATION/HYDROGEOLOGIC STUDY  

EPA Science Inventory

The Lubbock Land Treatment System Research and Demonstration Project, funded by Congress in 1978 (H.R. 9375), was designed to address the various issues concerning the use of slow rate land application of municipal wastewater. Information provided in the volume details the system...

325

Off-Axis Calibration of KamLAND and Modeling of the ``FourPi'' Calibration System  

NASA Astrophysics Data System (ADS)

KamLAND is 1000-ton liquid scintillator detector which uses the prompt and delayed signals from inverse beta decay to detect electron anti-neutrinos produced in nuclear reactors. KamLAND has made the first observation of the disappearance of reactor electron anti-neutrinos. The largest contribution to the systematic uncertainty in KamLAND is the fiducial volume uncertainty (4.7 % out of a total 6.5 % ). Until now the detector has been calibrated using gamma-ray sources of known energy deployed along the detector's vertical axis. A new 4? calibration system allows for off-axis source deployment throughout the entire fiducial volume. The 4 ? system is expected to reduce the fiducial volume uncertainty from 4.7 % to ˜ 1-2 % , and improve KamLAND's sensitivity in the determination of the mass-difference parameter ?m12^2 . The 4? system is currently in the initial stages of off-axis deployment. An off-line calculation is used to predict the location of the gamma-ray sources within the detector. The calculation takes into account the systems geometry, buoyancy effects in the liquid scintillator, and gravitational deflection of the 4? pole from its neutral axis (deflection correction incorporates both a theoretical model, and survey data). Comparison of the predicted source location with the vertex reconstructed using the KamLAND analysis software, allows for an investigation of the biases in the reconstruction procedure.

Elor, Gilly

2006-10-01

326

Bioenergy costs and potentials with special attention to implications for the land system  

NASA Astrophysics Data System (ADS)

In the coming decades, an increasing competition for global land and water resources can be expected, due to rising demand for agricultural products, goals of nature conservation, and changing production conditions due to climate change. Especially biomass from cellulosic bioenergy crops, such as Miscanthus or poplar, is being proposed to play a substantial role in future energy systems if climate policy aims at stabilizing greenhouse gas (GHG) concentration at low levels. However, the potential of bioenergy for climate change mitigation remains unclear due to large uncertainties about future agricultural yield improvements, land availability for biomass plantations, and implications for the land system. In order to explore the cost-effective contribution of bioenergy to a low carbon transition with special attention to implications for the land system, we present a modeling framework with detailed biophysical and economic representation of the land and energy sector: We have linked the global dynamic vegetation and water balance model LPJmL (Bondeau et al. 2007, Rost et al. 2008), the global land and water use model MAgPIE (Lotze-Campen et al. 2008, Popp et al. 2010), and the global energy-economy-climate model ReMIND (Leimbach et al. 2009). In this modeling framework LPJmL supplies spatially explicit (0.5° resolution) agricultural yields as well as carbon and water stocks and fluxes. Based on this biophysical input MAgPIE delivers cost-optimized land use patterns (0.5° resolution), associated GHG emissions and rates of future yield increases in agricultural production. Moreover, shadow prices are calculated for irrigation water (as an indicator for water scarcity), food commodities, and bioenergy (as an indicator for changes in production costs) under different land use constraints such as forest conservation for climate change mitigation and as a contribution to biodiversity conservation. The energy-economy-climate model ReMIND generates the demand for bioenergy, taking into account the direct competition with other energy technology options for GHG mitigation, based on economic costs of bioenergy production. As a result, we find that bioenergy from specialized grassy and woody bioenergy crops can contribute approximately 100 EJ in 2055 and up to 300 EJ of primary energy in 2095. Protecting natural forests decreases biomass availability for energy production in the medium run, but not in the long run. Reducing the land available for agricultural use can partially be compensated for by higher rates of technological change in agriculture; however, bioenergy crops will occupy large shares of available cropland in both scenarios. In addition, our trade-off analysis indicates that forest protection combined with large-scale cultivation of dedicated bioenergy is likely to affect bioenergy potentials, but also to increase global food prices and increase water scarcity.

Popp, A.; Lotze-Campen, H.; Dietrich, J.; Klein, D.; Bauer, N.; Krause, M.; Beringer, T.; Gerten, D.

2011-12-01

327

Development of automatic and manual flight director landing systems for the XV-15 tilt rotor aircraft in helicopter mode  

NASA Technical Reports Server (NTRS)

The objective of this effort is to determine IFR approach path and touchdown dispersions for manual and automatic XV-15 tilt rotor landings, and to develop missed approach criteria. Only helicopter mode XV-15 operation is considered. The analysis and design sections develop the automatic and flight director guidance equations for decelerating curved and straight-in approaches into a typical VTOL landing site equipped with an MLS navigation aid. These system designs satisfy all known pilot-centered, guidance and control requirements for this flying task. Performance data, obtained from nonstationary covariance propagation dispersion analysis for the system, are used to develop the approach monitoring criteria. The autoland and flight director guidance equations are programmed for the VSTOLAND 1819B digital computer. The system design dispersion data developed through analysis and the 1819B digital computer program are verified and refined using the fixed-base, man-in-the-loop XV-15 VSTOLAND simulation.

Hofmann, L. G.; Hoh, R. H.; Jewell, W. F.; Teper, G. L.; Patel, P. D.

1978-01-01

328

Analysis of the geomorphology surrounding the Chang'e-3 landing site  

NASA Astrophysics Data System (ADS)

Chang'e-3 (CE-3) landed on the Mare Imbrium basin in the east part of Sinus Iridum (19.51°W, 44.12°N), which was China's first soft landing on the Moon and it started collecting data on the lunar surface environment. To better understand the environment of this region, this paper utilizes the available high-resolution topography data, image data and geological data to carry out a detailed analysis and research on the area surrounding the landing site (Sinus Iridum and 45 km×70 km of the landing area) as well as on the topography, landform, geology and lunar dust of the area surrounding the landing site. A general topographic analysis of the surrounding area is based on a digital elevation model and digital elevation model data acquired by Chang'e-2 that have high resolution; the geology analysis is based on lunar geological data published by USGS; the study on topographic factors and distribution of craters and rocks in the surrounding area covering 4 km×4 km or even smaller is based on images from the CE-3 landing camera and images from the topographic camera; an analysis is done of the effect of the CE-3 engine plume on the lunar surface by comparing images before and after the landing using data from the landing camera. A comprehensive analysis of the results shows that the landing site and its surrounding area are identified as typical lunar mare with flat topography. They are suitable for maneuvers by the rover, and are rich in geological phenomena and scientific targets, making it an ideal site for exploration.

Li, Chun-Lai; Mu, Ling-Li; Zou, Xiao-Duan; Liu, Jian-Jun; Ren, Xin; Zeng, Xing-Guo; Yang, Yi-Man; Zhang, Zhou-Bin; Liu, Yu-Xuan; Zuo, Wei; Li, Han

2014-12-01

329

A regional analysis of drivers and impacts of land cover change and long-term land cover trends in the Great Basin, United States  

NASA Astrophysics Data System (ADS)

An improved understanding of land use/land cover change at local and regional scales is important in an increasingly human-dominated biosphere. The land surface provides resources necessary for human survival (e.g., cropland, water, raw materials) as well as providing other services such as habitat for native species, carbon storage, and nutrient cycling. A goal of land change science is to identify where land cover change is taking place, understand how land use may affect that change, and determine what the consequences of change may be. In the Great Basin Desert of the Western U.S., an important form of land cover change is invasion by non-native cheatgrass (Bromus tectorum). Cheatgrass invasion destroys native shrub ecosystems, leading to a loss of biodiversity, loss of viable rangeland and increased fire frequency. In this work, I show how remote sensing can be used to detect the regional and local extents of cheatgrass invasion. Remote sensing results are then used to assess the spatial patterns of cheatgrass invasion over time to determine how land use might have affected invasion. Further, I consider the long-term impacts of cheatgrass invasion on biodiversity and carbon storage in the Great Basin. In addition to an analysis of cheatgrass, this thesis presents a new methodology for time series modeling, which can be used to better interpret annual and inter-annual vegetation community phenology. I apply this modeling methodology to all land cover in the Great Basin to assess long-term land cover trends and localized anomalous response within the range of land cover classes present. By investigating regional land cover change I am able to provide more detailed analysis of the drivers of change for land managers while working at a scale relevant to studies of global environmental change.

Bradley, Bethany Adella

330

Sensitivity analysis for the aerosol retrieval over land for MERIS  

Microsoft Academic Search

The inversion of aerosol characteristics over DDV (Dark Dense Vegetation) targets is an intermediate and important step whenever atmospheric correction over land for the Envisat\\/MERIS instrument is performed. We present here the results of an error budget for every step of this inversion. We show that the crucial step is DDV selection based on a threshold on the ARVI (Atmospherically

C. Schmechtig; V. Carrère; P. Dubuisson; J. C. Roger; R. Santer

2003-01-01

331

Methodological Advances in the Spatial Analysis of Land Fragmentation  

Microsoft Academic Search

This article evaluates the effect of moving window (MW) size on observed fragmentation spatial patterns and proposes a method to identify an effective MW size using Simpson's diversity index. To test the robustness of the proposed method, we demonstrate its use in six cities in the Phoenix metropolitan area that have substantial variation in land composition and configuration. Next we

Sainan Zhang; Abigail M. York; Christopher G. Boone; Milan Shrestha

2012-01-01

332

Multi-Terrain Earth Landing Systems Applicable for Manned Space Capsules  

NASA Technical Reports Server (NTRS)

A key element of the President's Vision for Space Exploration is the development of a new space transportation system to replace Shuttle that will enable manned exploration of the moon, Mars, and beyond. NASA has tasked the Constellation Program with the development of this architecture, which includes the Ares launch vehicle and Orion manned spacecraft. The Orion spacecraft must carry six astronauts and its primary structure should be reusable, if practical. These requirements led the Constellation Program to consider a baseline land landing on return to earth. To assess the landing system options for Orion, a review of current operational parachute landing systems such as those used for the F-111 escape module and the Soyuz is performed. In particular, landing systems with airbags and retrorockets that would enable reusability of the Orion capsule are investigated. In addition, Apollo tests and analyses conducted in the 1960's for both water and land landings are reviewed. Finally, tests and dynamic finite element simulations to understand land landings for the Orion spacecraft are also presented.

Fasanella, Edwin L.

2008-01-01

333

Preliminary Analysis of the efficacy of Artificial neural Network (ANN) and Cellular Automaton (CA) based Land Use Models in Urban Land-Use Planning  

NASA Astrophysics Data System (ADS)

This research provides an opportunity of collaboration between urban planners and modellers by providing a clear theoretical foundations on the two most widely used urban land use models, and assessing the effectiveness of applying the models in urban planning context. Understanding urban land cover change is an essential element for sustainable urban development as it affects ecological functioning in urban ecosystem. Rapid urbanization due to growing inclination of people to settle in urban areas has increased the complexities in predicting that at what shape and size cities will grow. The dynamic changes in the spatial pattern of urban landscapes has exposed the policy makers and environmental scientists to great challenge. But geographic science has grown in symmetry to the advancements in computer science. Models and tools are developed to support urban planning by analyzing the causes and consequences of land use changes and project the future. Of all the different types of land use models available in recent days, it has been found by researchers that the most frequently used models are Cellular Automaton (CA) and Artificial Neural Networks (ANN) models. But studies have demonstrated that the existing land use models have not been able to meet the needs of planners and policy makers. There are two primary causes identified behind this prologue. First, there is inadequate understanding of the fundamental theories and application of the models in urban planning context i.e., there is a gap in communication between modellers and urban planners. Second, the existing models exclude many key drivers in the process of simplification of the complex urban system that guide urban spatial pattern. Thus the models end up being effective in assessing the impacts of certain land use policies, but cannot contribute in new policy formulation. This paper is an attempt to increase the knowledge base of planners on the most frequently used land use model and also assess the relative effectiveness of the two models, ANN and CA, in urban planning. The questions that are addressed in this research are: a) What makes ANN models different from CA models?; b) Which model has higher accuracy in predicting future urban land use change?; and c) Are the models effective enough in guiding urban land use policies and strategies? The models that are used for this research are Multilayer Perceptron (MLP) and CA model, available in IDRISI Taiga. Since, the objective is to perform a comparative analysis and draw general inferences irrespective of specific urban policies, the availability of data was given more emphasis over the selection of particular location. Urban area in Massachusetts was chosen to conduct the study due to data availability. Extensive literature review was performed to understand the functionality of the two models. The models were applied to predict future changes and the accuracy assessment was performed using standard matrix. Inferences were drawn about the applicability of the models in urban planning context along with recommendations. This research will not only develop understanding of land use models among urban planners, but also will create an environment of coupled research between planners and modellers.

Harun, R.

2013-05-01

334

Assessment on EXPERT Descent and Landing System Aerodynamics  

NASA Astrophysics Data System (ADS)

EXPERT is a re-entry vehicle designed for validation of aero-thermodynamic models, numerical schemes in Computational Fluid Dynamics codes and test facilities for measuring flight data under an Earth re-entry environment. This paper addresses the design for the descent and landing sequence for EXPERT. It includes the descent sequence, the choice of drogue and main parachutes, and the parachute deployment condition, which can be supersonic or subsonic. The analysis is based mainly on an engineering tool, PASDA, together with some hand calculations for parachute sizing and design. The tool consists of a detailed 6-DoF simulation performed with the aerodynamics database of the vehicle, an empirical wakes model and the International Standard Atmosphere database. The aerodynamics database for the vehicle is generated by DNW experimental data and CFD codes within the framework of an ESA contract to CIRA. The analysis will be presented in terms of altitude, velocity, accelerations, angle-of- attack, pitch angle and angle of rigging line. Discussion on the advantages and disadvantages of each parachute deployment condition is included in addition to some comparison with the available data based on a Monte-Carlo method from a Russian company, FSUE NIIPS. Sensitivity on wind speed to the performance of EXPERT is shown to be strong. Supersonic deployment of drogue shows a better performance in stability at the expense of a larger G-load than those from the subsonic deployment of drogue. Further optimization on the parachute design is necessary in order to fulfill all the EXPERT specifications.

Wong, H.; Muylaert, J.; Northey, D.; Riley, D.

2009-01-01

335

Global land information system (GLIS) access to worldwide Landsat data  

USGS Publications Warehouse

The Landsat Technical Working Group (LTWG) and the Landsat Ground Station Operations Working Group (LGSOWG) have encouraged Landsat receiving stations around the world to share information about their data holdings through the exchange of metadata records. Receiving stations forward their metadata records to the U.S. Geological Survey's EROS Data Center (EDC) on a quarterly basis. The EDC maintains the records for each station, coordinates changes to the database, and provides metadata to the stations as requested. The result is a comprehensive international database listing most of the world's Landsat data acquisitions This exchange of information began in the early 1980's with the inclusion in the EDC database os scenes acquired by a receiving station in Italy. Through the years other stations have agreed to participate; currently ten of the seventeen stations actively share their metadata records. Coverage maps have been generated to depict the status of the database. The Worldwide Landsat database is also available though the Global Land Information System (GLIS).

Smith, Timothy B.; Goodale, Katherine L.

1993-01-01

336

Braking and cornering studies on an air cushion landing system  

NASA Technical Reports Server (NTRS)

An experimental investigation was conducted to evaluate several concepts for braking and steering a vehicle equipped with an air cushion landing system (ACLS). The investigation made use of a modified airboat equipped with an ACLS. Braking concepts were characterized by the average deceleration of the vehicle. Reduced lobe flow and cavity venting braking concepts were evaluated in this program. The cavity venting braking concept demonstrated the best performance, producing decelerations on the test vehicle on the same order as moderate braking with conventional wheel brakes. Steering concepts were evaluated by recording the path taken while attempting to follow a prescribed maneuver. The steering concepts evaluated included using rudders only, using differential lobe flow, and using rudders combined with a lightly loaded, nonsteering center wheel. The latter concept proved to be the most accurate means of steering the vehicle on the ACLS, producing translational deviations two to three times higher than those from conventional nose-gear steering. However, this concept was still felt to provide reasonably precise steering control for the ACLS-equipped vehicle.

Daugherty, R. H.

1983-01-01

337

Towards decision-based global land use models for improved understanding of the Earth system  

NASA Astrophysics Data System (ADS)

A primary goal of Earth system modelling is to improve understanding of the interactions and feedbacks between human decision making and biophysical processes. The nexus of land use and land cover change (LULCC) and the climate system is an important example. LULCC contributes to global and regional climate change, while climate affects the functioning of terrestrial ecosystems and LULCC. However, at present, LULCC is poorly represented in global circulation models (GCMs). LULCC models that are explicit about human behaviour and decision-making processes have been developed at local to regional scales, but the principles of these approaches have not yet been applied to the global scale level in ways that deal adequately with both direct and indirect feedbacks from the climate system. In this article, we explore current knowledge about LULCC modelling and the interactions between LULCC, GCMs and dynamic global vegetation models (DGVMs). In doing so, we propose new ways forward for improving LULCC representations in Earth system models. We conclude that LULCC models need to better conceptualise the alternatives for upscaling from the local to global scale. This involves better representation of human agency, including processes such as learning, adaptation and agent evolution, formalising the role and emergence of governance structures, institutional arrangements and policy as endogenous processes and better theorising about the role of teleconnections and connectivity across global networks. Our analysis underlines the importance of observational data in global-scale assessments and the need for coordination in synthesising and assimilating available data.

Rounsevell, M. D. A.; Arneth, A.; Alexander, P.; Brown, D. G.; de Noblet-Ducoudré, N.; Ellis, E.; Finnigan, J.; Galvin, K.; Grigg, N.; Harman, I.; Lennox, J.; Magliocca, N.; Parker, D.; O'Neill, B. C.; Verburg, P. H.; Young, O.

2014-02-01

338

23 CFR 972.212 - Federal lands safety management system (SMS).  

Code of Federal Regulations, 2012 CFR

...TRANSPORTATION FEDERAL LANDS HIGHWAYS FISH AND WILDLIFE SERVICE MANAGEMENT SYSTEMS Fish and Wildlife Service Management Systems § 972.212...collection, maintenance and reporting of a database that includes: (i) Accident...

2012-04-01

339

23 CFR 972.210 - Federal lands bridge management system (BMS).  

Code of Federal Regulations, 2013 CFR

...LANDS HIGHWAYS FISH AND WILDLIFE SERVICE MANAGEMENT SYSTEMS Fish and Wildlife Service Management Systems...framework for a BMS: (1) A database and an ongoing program...the BMS. The minimum BMS database shall include:...

2013-04-01

340

23 CFR 972.208 - Federal lands pavement management system (PMS).  

Code of Federal Regulations, 2011 CFR

...LANDS HIGHWAYS FISH AND WILDLIFE SERVICE MANAGEMENT SYSTEMS Fish and Wildlife Service Management Systems...framework for a PMS: (1) A database and an ongoing program...the PMS. The minimum PMS database shall include:...

2011-04-01

341

23 CFR 972.212 - Federal lands safety management system (SMS).  

Code of Federal Regulations, 2010 CFR

...TRANSPORTATION FEDERAL LANDS HIGHWAYS FISH AND WILDLIFE SERVICE MANAGEMENT SYSTEMS Fish and Wildlife Service Management Systems § 972.212...collection, maintenance and reporting of a database that includes: (i) Accident...

2010-04-01

342

23 CFR 972.210 - Federal lands bridge management system (BMS).  

Code of Federal Regulations, 2014 CFR

...LANDS HIGHWAYS FISH AND WILDLIFE SERVICE MANAGEMENT SYSTEMS Fish and Wildlife Service Management Systems...framework for a BMS: (1) A database and an ongoing program...the BMS. The minimum BMS database shall include:...

2014-04-01

343

23 CFR 972.212 - Federal lands safety management system (SMS).  

Code of Federal Regulations, 2013 CFR

...TRANSPORTATION FEDERAL LANDS HIGHWAYS FISH AND WILDLIFE SERVICE MANAGEMENT SYSTEMS Fish and Wildlife Service Management Systems § 972.212...collection, maintenance and reporting of a database that includes: (i) Accident...

2013-04-01

344

23 CFR 972.208 - Federal lands pavement management system (PMS).  

Code of Federal Regulations, 2010 CFR

...LANDS HIGHWAYS FISH AND WILDLIFE SERVICE MANAGEMENT SYSTEMS Fish and Wildlife Service Management Systems...framework for a PMS: (1) A database and an ongoing program...the PMS. The minimum PMS database shall include:...

2010-04-01

345

23 CFR 972.208 - Federal lands pavement management system (PMS).  

Code of Federal Regulations, 2014 CFR

...LANDS HIGHWAYS FISH AND WILDLIFE SERVICE MANAGEMENT SYSTEMS Fish and Wildlife Service Management Systems...framework for a PMS: (1) A database and an ongoing program...the PMS. The minimum PMS database shall include:...

2014-04-01

346

23 CFR 972.212 - Federal lands safety management system (SMS).  

Code of Federal Regulations, 2011 CFR

...TRANSPORTATION FEDERAL LANDS HIGHWAYS FISH AND WILDLIFE SERVICE MANAGEMENT SYSTEMS Fish and Wildlife Service Management Systems § 972.212...collection, maintenance and reporting of a database that includes: (i) Accident...

2011-04-01

347

23 CFR 972.208 - Federal lands pavement management system (PMS).  

Code of Federal Regulations, 2012 CFR

...LANDS HIGHWAYS FISH AND WILDLIFE SERVICE MANAGEMENT SYSTEMS Fish and Wildlife Service Management Systems...framework for a PMS: (1) A database and an ongoing program...the PMS. The minimum PMS database shall include:...

2012-04-01

348

23 CFR 972.208 - Federal lands pavement management system (PMS).  

Code of Federal Regulations, 2013 CFR

...LANDS HIGHWAYS FISH AND WILDLIFE SERVICE MANAGEMENT SYSTEMS Fish and Wildlife Service Management Systems...framework for a PMS: (1) A database and an ongoing program...the PMS. The minimum PMS database shall include:...

2013-04-01

349

23 CFR 972.212 - Federal lands safety management system (SMS).  

Code of Federal Regulations, 2014 CFR

...TRANSPORTATION FEDERAL LANDS HIGHWAYS FISH AND WILDLIFE SERVICE MANAGEMENT SYSTEMS Fish and Wildlife Service Management Systems § 972.212...collection, maintenance and reporting of a database that includes: (i) Accident...

2014-04-01

350

23 CFR 972.210 - Federal lands bridge management system (BMS).  

Code of Federal Regulations, 2011 CFR

...LANDS HIGHWAYS FISH AND WILDLIFE SERVICE MANAGEMENT SYSTEMS Fish and Wildlife Service Management Systems...framework for a BMS: (1) A database and an ongoing program...the BMS. The minimum BMS database shall include:...

2011-04-01

351

23 CFR 972.210 - Federal lands bridge management system (BMS).  

Code of Federal Regulations, 2010 CFR

...LANDS HIGHWAYS FISH AND WILDLIFE SERVICE MANAGEMENT SYSTEMS Fish and Wildlife Service Management Systems...framework for a BMS: (1) A database and an ongoing program...the BMS. The minimum BMS database shall include:...

2010-04-01

352

23 CFR 972.210 - Federal lands bridge management system (BMS).  

Code of Federal Regulations, 2012 CFR

...LANDS HIGHWAYS FISH AND WILDLIFE SERVICE MANAGEMENT SYSTEMS Fish and Wildlife Service Management Systems...framework for a BMS: (1) A database and an ongoing program...the BMS. The minimum BMS database shall include:...

2012-04-01

353

AGROFORESTRY SYSTEMS: INTEGRATED LAND USE TO STORE AND CONSERVE CARBON  

EPA Science Inventory

Agroforestry is a promising land use practice to maintain or increase agricultural productivity while preserving or improving fertility. n extensive literature survey was conducted to evaluate the carbon dynamics of agroforestry practices and to assess their potential to store ca...

354

Multi-Agent Systems for the Simulation of Land-Use and Land-Cover Change: A Review  

Microsoft Academic Search

This article presents an overview of multi-agent system models of land-use\\/cover change (MAS\\/LUCC models). This special class of LUCC models combines a cellular landscape model with agent-based representations of decision making, integrating the two components through specification of interdependencies and feedbacks between agents and their environment. The authors review alternative LUCC modeling techniques and discuss the ways in which MAS\\/LUCC

Dawn C. Parker; Steven M. Manson; Marco A. Janssen; Matthew J. Hoffmann; Peter Deadman

2003-01-01

355

System architecture and market aspects of an European Land Mobile Satellite System via EMS  

NASA Astrophysics Data System (ADS)

The paper describes an implementation scenario of a Land Mobile Satellite System via the EMS (European Mobile System) payload embarked on Italsat F-2. Some emphasis is given on market issues aiming at singling out business niches of Land Mobile Satellite Services (LMSS) in Europe. Other crucial issues exist such as: the alternate/competitive systems, the problems of interworking with other existing and/or planned systems, the definition of network architecture that better fits the user requirements, the marketing strategy and, last but not least, the financial evaluation of the project. The paper, on the basis of a study performed by Telespazio on behalf of ESA, discusses some of these issues with emphasis on competitive market aspects.

Ananasso, F.; Mistretta, I.

1992-03-01

356

Autonomous Hovering and Landing of a Quad-rotor Micro Aerial Vehicle by Means of on Ground Stereo Vision System  

Microsoft Academic Search

On ground stereo vision system is used for autonomous hovering and landing of a quadrotor Micro Aerial Vehicle (MAV). This kind of system has an advantage to support embedded vision system for autonomous hovering and landing, since an embedded vision system occasionally gives inaccurate distance calculation due to either vibration problem or unknown geometry of the landing target. Color based

Dwi Pebrianti; Farid Kendoul; Syaril Azrad; Wei Wang; Kenzo Nonami

2010-01-01

357

Space shuttle navigation analysis. Volume 2: Baseline system navigation  

NASA Technical Reports Server (NTRS)

Studies related to the baseline navigation system for the orbiter are presented. The baseline navigation system studies include a covariance analysis of the Inertial Measurement Unit calibration and alignment procedures, postflight IMU error recovery for the approach and landing phases, on-orbit calibration of IMU instrument biases, and a covariance analysis of entry and prelaunch navigation system performance.

Jones, H. L.; Luders, G.; Matchett, G. A.; Rains, R. G.

1980-01-01

358

An Analysis: Outdoor Recreation on Government Lands in Texas.  

E-print Network

million ~rllicll .ctras used to expand antl improve state facilities antl help finance the clevelopment of municipal antl county parks and recreation areas and several recreation sites on reservoirs operated by state river authorities. Impact.... Consequently, the General policy of most districts has been to acquire streams and rivers has been under- only land needed for the project or for necessary he demands for municipal, indus- maintenance and operation of the reservoir and tion uses, as well...

Reed, David J.; Reid, Leslie M.

1969-01-01

359

Modeling the influences of land reclamation on groundwater systems: A case study in Shekou peninsula, Shenzhen, China  

E-print Network

Modeling the influences of land reclamation on groundwater systems: A case study in Shekou form 16 February 2010 Accepted 18 April 2010 Available online 24 April 2010 Keywords: Land reclamation of land has been reclaimed around the Shekou peninsula, Shenzhen, China. Land reclamation may have

Jiao, Jiu Jimmy

360

Snow process modeling in the North American Land Data Assimilation System (NLDAS)  

E-print Network

Snow process modeling in the North American Land Data Assimilation System (NLDAS): 1. Evaluation of model-simulated snow cover extent Justin Sheffield,1 Ming Pan,1 Eric F. Wood,1 Kenneth E. Mitchell,2) and consists of two parts: (1) assessment of land surface model simulations of snow cover extent and (2

Robock, Alan

361

Expert system classification of urban land use\\/cover for Delhi, India  

Microsoft Academic Search

This study presents the results of classifying land use\\/land cover for Delhi, India using an expert system approach. For this study Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data of 22 September 2003 were used. The research goals of this project are two?fold. In one respect, the research goal is to report on the extent covered by urbanization using

Elizabeth A. Wentz; David Nelson; Atiqur Rahman; William L. Stefanov; Shoursaseni Sen Roy

2008-01-01

362

Cartography and Information Systems for the Luna-Glob Landing Sites  

NASA Astrophysics Data System (ADS)

We provide cartography and information system support to the LUNA-GLOB mission and assess candidate landing sites [1] on the basis of different available remote sensing data sets. The main goal of our work is to identify science opportunities in the sub-polar areas and to detect possible hazards for any landing spacecraft.

Kokhanov, A.; Karachevtseva, I.; Oberst, J.; Zubarev, A.; Robinson, M. S.

2012-09-01

363

Impact of agricultural land management systems on soil microbial diversity and plant disease  

Technology Transfer Automated Retrieval System (TEKTRAN)

Increased diversity of fungal rDNA ITS-1 amplicons, as measured by the Shannon-Weiner index, was associated with land management practices that minimise soil disturbance (bahiagrass pasture and undisturbed weed fallow) when compared with organic or conventional land management systems. Diversity de...

364

Efficient Methods of Clutter Suppression for Coexisting Land and Weather Clutter Systems  

E-print Network

1 Efficient Methods of Clutter Suppression for Coexisting Land and Weather Clutter Systems C¸ a and weather clutter signals is a common problem in many radar applications. Although the optimal method for land-weather clutter suppression is known, it is usually not amenable to implementation due

Yýlmaz, �zgür

365

FORT HOOD LAND MANAGEMENT SYSTEM (LMS) MILITARY FIELD APPLICATION SITE FY99 IN-PROGRESS REVIEW  

EPA Science Inventory

The purpose of the Land Management System (LMS) is to provide relevant science, tools, and information to land and water resource managers and decision makers with the goal of enhancing their ability to understand and communicate past, current, and potential impacts of management...

366

On Modeling A Dynamic Hybrid System with Constraints: Computing Aircraft Landing  

E-print Network

On Modeling A Dynamic Hybrid System with Constraints: Computing Aircraft Landing Trajectories of computing trajectories of a set of aircraft in their final descent, right before landing. Trajectories must be compatible with aircraft dynamics while keeping distance between aircraft large enough. Our objective

Artiouchine, Konstantin

367

Development and implementation of the Virginia agronomic land use evaluation system (VALUES)  

Microsoft Academic Search

There is currently a great deal of concern about the movement of nutrients from agricultural land to surface and ground water. This concern centers on nitrogen (N) and phosphorus (P). These two nutrients greatly stimulate algal growth, ultimately causing a depletion of oxygen which adversely affects aquatic vegetation, and higher marine life. The Virginia Agronomic Land Use Evaluation System (VALUES)

S. J. Donohue; T. W. Simpson; J. C. Baker; M. M. Monnett; G. W. Hawkins

1994-01-01

368

LUBBOCK LAND TREATMENT SYSTEM RESEARCH AND DEMONSTRATION PROJECT. VOLUME 5. EXECUTIVE SUMMARY  

EPA Science Inventory

The Lubbock Land Treatment System Research and Demonstration Project, funded by Congress in 1978 (H.R. 9375), was designed to address the various issues concerning the use of slow rate land application of municipal wastewater. The project involved the (1) physical expansion of ov...

369

LUBBOCK LAND TREATMENT SYSTEM RESEARCH AND DEMONSTRATION PROJECT. VOLUME 2. PERCOLATE INVESTIGATION IN THE ROOT ZONE  

EPA Science Inventory

The Lubbock Land Treatment System Research and Demonstration Project, funded by Congress in 1978 (H.R. 9375), was designed to address the various issues concerning the use of slow rate land application of municipal wastewater. The project involved the (1) physical expansion of an...

370

Joint analysis of solar neutrino and new KamLAND data in the RSFP framework  

E-print Network

A joint analysis of solar neutrino data together with the new KamLAND data is presented in the RSFP framework. It is investigated that how the new KamLAND data effects the allowed regions at different $\\mu B$ values. A limit on $\\mu B$ value is found at the different confidence level intervals. It is shown that the RSFP scenerio does not have a crucial role on the solar neutrino data.

D. Yilmaz

2008-10-06

371

An econometric analysis of changes in arable land utilization using multinomial logit model in Pinggu district, Beijing, China.  

PubMed

Arable land in China has been decreasing as a result of rapid population growth and economic development as well as urban expansion, especially in developed regions around cities where quality farmland quickly disappears. This paper analyzed changes in arable land utilization during 1993-2008 in the Pinggu district, Beijing, China, developed a multinomial logit (MNL) model to determine spatial driving factors influencing arable land-use change, and simulated arable land transition probabilities. Land-use maps, as well as social-economic and geographical data were used in the study. The results indicated that arable land decreased significantly between 1993 and 2008. Lost arable land shifted into orchard, forestland, settlement, and transportation land. Significant differences existed for arable land transitions among different landform areas. Slope, elevation, population density, urbanization rate, distance to settlements, and distance to roadways were strong drivers influencing arable land transition to other uses. The MNL model was proved effective for predicting transition probabilities in land use from arable land to other land-use types, thus can be used for scenario analysis to develop land-use policies and land-management measures in this metropolitan area. PMID:23774750

Xu, Yueqing; McNamara, Paul; Wu, Yanfang; Dong, Yue

2013-10-15

372

Land degradation and Poverty in maize producing areas of Kenya - Development of an interdisciplinary analysis framework using GIS and remote sensing  

NASA Astrophysics Data System (ADS)

Land degradation causes poverty and vice versa. But both processes are highly complex, hard to predict and to mitigate, and need insights from different perspectives. Therefore an interdisciplinary framework for the understanding of land degradation processes by linking biophysical data with socio-economic trends is necessary. Agricultural systems in Kenya are affected by land degradation and especially recent developments such as agricultural innovations including the use of hybrid seeds and chemical fertilizer have an impact on the environment. Vegetation analysis, used as a proxy indicator for the status of land is carried out to monitor environmental changes in maize producing areas of western Kenya. One of the methods used in this study includes time series analysis of vegetation data from 2001 to 2010 based on MODIS NDVI data with 250m and 500m resolution. Occurring trends are linked to rainfall estimation data and annually classified land use cover data with 500m resolution based on MODIS within the same time period. Analysis of significant trends in combination with land cover information show recent land change dynamics. As these changes are not solely biophysically driven, socio-economic variables representing marginality - defined as the root cause of poverty- are also considered. The most poor are primarily facing the most vulnerable and thereby less fertile soils. Moreover they are lacking access to information to eventually use existing potential. This makes the analysis of changing environmental processes and household characteristics in the interplay important to understand in order to highlight the most influencing variables. Within the new interdisciplinary analysis framework the concept of marginality includes different dimensions referring to certain livelihood characteristics such as health and education which describe a more diverse picture of poverty than the known economic perspective. Household surveys and census data from different time periods allow the analysis of socio-economic trends and link this information to biophysical factors. If relationships between certain variables are understood, adapted land management strategies can be developed. This study aims at linking pixel-level information with established remote sensing methods to the socio-economic concept of marginality based on household surveys and census data on administrative levels. Besides remote sensing and statistical analysis of socio-economic data a GIS is used for geospatial analysis. As most studies on land degradation focus on biophysical aspects such as vegetation or soil degradation this study uses an innovative approach by integrating biophysical analysis without neglecting a human oriented approach which plays a key role in environmental systems nowadays. This interdisciplinary research helps to get closer to the right and adapted policies and land management strategies as land degradation processes do not stick to administrative boundaries but policy advice does.

Graw, Valerie; Nkonya, Ephraim; Menz, Gunter

2014-05-01

373

Neptune Aerocapture Systems Analysis  

Microsoft Academic Search

A Neptune Aerocapture Systems Analysis is completed to determine the feasibility, bene- fit and risk of an aeroshell aerocapture system for Neptune and to identify technology gaps and technology performance goals. The high fidelity systems analysis is completed by a five center NASA team and includes the following disciplines and analyses: science; mission de- sign; aeroshell configuration screening and definition;

Mary Kae Lockwood

374

Analysis and prediction of household location choice in Grand Lyon with urban land use simulation tool UrbanSim  

E-print Network

Analysis and prediction of household location choice in Grand Lyon with urban land use simulation by adding other UrbanSim models to the application. Keywords: household location choice, land use modelling population, employment, land use and transportation is a necessary precondition of efficient urban planning

Paris-Sud XI, Université de

375

Direct Sensor Orientation of a Land-Based Mobile Mapping System  

PubMed Central

A land-based mobile mapping system (MMS) is flexible and useful for the acquisition of road environment geospatial information. It integrates a set of imaging sensors and a position and orientation system (POS). The positioning quality of such systems is highly dependent on the accuracy of the utilized POS. This limitation is the major drawback due to the elevated cost associated with high-end GPS/INS units, particularly the inertial system. The potential accuracy of the direct sensor orientation depends on the architecture and quality of the GPS/INS integration process as well as the validity of the system calibration (i.e., calibration of the individual sensors as well as the system mounting parameters). In this paper, a novel single-step procedure using integrated sensor orientation with relative orientation constraint for the estimation of the mounting parameters is introduced. A comparative analysis between the proposed single-step and the traditional two-step procedure is carried out. Moreover, the estimated mounting parameters using the different methods are used in a direct geo-referencing procedure to evaluate their performance and the feasibility of the implemented system. Experimental results show that the proposed system using single-step system calibration method can achieve high 3D positioning accuracy. PMID:22164015

Rau, Jiann-Yeou; Habib, Ayman F.; Kersting, Ana P.; Chiang, Kai-Wei; Bang, Ki-In; Tseng, Yi-Hsing; Li, Yu-Hua

2011-01-01

376

Efficiency Analysis of Agricultural Land Use Based on DEA Method: A Case Study among APEC Economies  

Microsoft Academic Search

This study made an analysis of agricultural land use efficiency in APEC (Asia-Pacific Economic Cooperation) with an objective to find which member economy can produce at least the same amount of food production with less resources input. To do so, data envelopment analysis (DEA), a useful method to evaluate the efficiency and productivity of a number of producers which consume

Qiangyi Yu; Huajun Tang; Youqi Chen; Wenbin Wu; Peng Yang; Pengqin Tang; Xinguo Xu

2011-01-01

377

Spatial correlation characteristic analysis of land clutter for PRC_cw radar at x-band  

NASA Astrophysics Data System (ADS)

Pseudo-random code continuous wave (PRC_CW) radar, which is low probability of intercept and has good ability of target detection in clutter, is widely used in fields of target detection, tracking, guiding, detecting underground, and so on. Temporal distribution function of land clutter was always studied and the backscatter from land was supposed spatially homogeneous. In fact, the backscatter from various resolution cells is obviously different, especially under complicated land background, since the number of clutter sources is too great. So it is very important for spatial correlation characteristic analysis of land clutter. In this paper, spatial correlation characteristic of land clutter for PRC_CW radar at X-band was analyzed. The time spread of radar echo exists while the radar works at low grazing angle. To PRC_CW radar, the time spread of radar echo results in that the receiving signal amplitude at a certain time is the sum of many spread codes. In this paper, spatial amplitude distribution and spatial correlation function of some typical land clutter under the condition of single code were firstly discussed. Then, we point out the problem of time spread of echo signal at low grazing angle and proposed a superposition method to simulate real clutter echo of PRC_CW radar. Finally we analyzed the spatial correlation characteristics of some typical land clutter.

Cao, Zhiguo; Zhang, Zhiyong; Zhang, Tianxu

1998-09-01

378

Analysis of land use and land cover change in a coastal area of Rio de Janeiro using high-resolution remotely sensed data  

NASA Astrophysics Data System (ADS)

Coastal areas offer great recreational and economic opportunities, but require intensive resource management and environmental protection. Land use and land cover information provides a rapid and cost-effective means for monitoring and planning coastal area development. This study quantitatively describes spatiotemporal changes of land use and land cover over the last four decades in a coastal area of the state of Rio de Janeiro, Brazil. Historical aerial photographs from 1976 and satellite images from 1990 and 2012 were classified and analyzed. We used supervised classification and machine learning techniques to classify the images. An accuracy assessment of results was performed. Land use change statistics for the period indicate that urban areas have increased to the detriment of dense vegetation, salines, and bare soil. The analysis provides a basis for better control of anthropogenic impacts and geoconservation activities in this coastal area of Rio de Janeiro.

Avelar, Silvania; Tokarczyk, Piotr

2014-01-01

379

Developing land use scenario dynamics model by the integration of system dynamics model and cellular automata model  

Microsoft Academic Search

Modeling land use scenario changes and its potential impacts on the structure and function of the ecosystem in the typical\\u000a regions are helpful to understanding the interactive mechanism between land use system and ecological system. A Land Use Scenario\\u000a Dynamics (LUSD) model by the integration of System Dynamics (SD) model and Cellular Automata (CA) model is developed with\\u000a land use

Chunyang He; Peijun Shi; Jin Chen; Xiaobing Li; Yaozhong Pan; Jing Li; Yuechen Li; Jinggang Li

2005-01-01

380

Detection by Pilots of System Failures during Instrument Landings  

Microsoft Academic Search

The effects of gust disturbances and the pilot's participation mode in the control task on his work-load level and failure detection performance during a simulated low visibility landing approach are examined. We found that the participation mode had a strong effect on the pilot's work load, the induced work load being lowest when the pilot acted as a monitoring element

Arye R. Ephrath; Renwick E. Curry

1977-01-01

381

Disengaged Farmers: The Land Grant System's Overlooked Clientele  

Microsoft Academic Search

The land-grant university was founded to promote equality in American society by educating the common man, developing knowledge to solve problems, and by disseminating that knowledge to all who need it. The Cooperative Extension Service (CES) offers research based information and non-formal education to the public, and serves as a link between the universities' researchers and the citizen: However, some

S. Christian Mariger; Kathleen D. Kelsey

2003-01-01

382

Capturing interactions between nitrogen and hydrological cycles under historical climate and land use: Susquehanna watershed analysis with the GFDL Land Model LM3-TAN  

NASA Astrophysics Data System (ADS)

We developed a~process model LM3-TAN to assess the combined effects of direct human influences and climate change on Terrestrial and Aquatic Nitrogen (TAN) cycling. The model was developed by expanding NOAA's Geophysical Fluid Dynamics Laboratory land model LM3V-N of coupled terrestrial carbon and nitrogen (C-N) cycling and including new N cycling processes and inputs such as a~soil denitrification, point N sources to streams (i.e. sewage), and stream transport and microbial processes. Because the model integrates ecological, hydrological, and biogeochemical processes, it captures key controls of transport and fate of N in the vegetation-soil-river system in a comprehensive and consistent framework which is responsive to climatic variations and land use changes. We applied the model at 1/8° resolution for a study of the Susquehanna River basin. We simulated with LM3-TAN stream dissolved organic-N, ammonium-N, and nitrate-N loads throughout the river network, and we evaluated the modeled loads for 1986-2005 using data from 15 monitoring stations as well as a reported budget for the entire basin. By accounting for inter-annual hydrologic variability, the model was able to capture inter-annual variations of stream N loadings. While the model was calibrated with the stream N loads only at the last downstream station Marietta (40.02° N, 76.32° W), it captured the N loads well at multiple locations within the basin with different climate regimes, land use types, and associated N sources and transformations in the sub-basins. Furthermore, the calculated and previously reported N budgets agreed well at the level of the whole Susquehanna watershed. Here we illustrate how point and non-point N sources contribute to the various ecosystems are stored, lost, and exported via the river. Local analysis for 6 sub-basins showed combined effects of land use and climate on the soil denitrification rates, with the highest rates in the Lower Susquehanna sub-basin (extensive agriculture; Atlantic coastal climate) and the lowest rates in the West Branch Susquehanna sub-basin (mostly forest; Great Lakes and Midwest climate). In the re-growing secondary forests, most of the N from non-point sources was stored in the vegetation and soil, but in the agricultural lands most N inputs were removed by soil denitrification indicating that anthropogenic N applications could drive substantial increase of N2O emission, an intermediate of the denitrification process.

Lee, M.; Malyshev, S.; Shevliakova, E.; Jaffé, P. R.

2014-04-01

383

Capturing interactions between nitrogen and hydrological cycles under historical climate and land use: Susquehanna watershed analysis with the GFDL land model LM3-TAN  

NASA Astrophysics Data System (ADS)

We developed a process model LM3-TAN to assess the combined effects of direct human influences and climate change on terrestrial and aquatic nitrogen (TAN) cycling. The model was developed by expanding NOAA's Geophysical Fluid Dynamics Laboratory land model LM3V-N of coupled terrestrial carbon and nitrogen (C-N) cycling and including new N cycling processes and inputs such as a soil denitrification, point N sources to streams (i.e., sewage), and stream transport and microbial processes. Because the model integrates ecological, hydrological, and biogeochemical processes, it captures key controls of the transport and fate of N in the vegetation-soil-river system in a comprehensive and consistent framework which is responsive to climatic variations and land-use changes. We applied the model at 1/8° resolution for a study of the Susquehanna River Basin. We simulated with LM3-TAN stream dissolved organic-N, ammonium-N, and nitrate-N loads throughout the river network, and we evaluated the modeled loads for 1986-2005 using data from 16 monitoring stations as well as a reported budget for the entire basin. By accounting for interannual hydrologic variability, the model was able to capture interannual variations of stream N loadings. While the model was calibrated with the stream N loads only at the last downstream Susquehanna River Basin Commission station Marietta (40°02' N, 76°32' W), it captured the N loads well at multiple locations within the basin with different climate regimes, land-use types, and associated N sources and transformations in the sub-basins. Furthermore, the calculated and previously reported N budgets agreed well at the level of the whole Susquehanna watershed. Here we illustrate how point and non-point N sources contributing to the various ecosystems are stored, lost, and exported via the river. Local analysis of six sub-basins showed combined effects of land use and climate on soil denitrification rates, with the highest rates in the Lower Susquehanna Sub-Basin (extensive agriculture; Atlantic coastal climate) and the lowest rates in the West Branch Susquehanna Sub-Basin (mostly forest; Great Lakes and Midwest climate). In the re-growing secondary forests, most of the N from non-point sources was stored in the vegetation and soil, but in the agricultural lands most N inputs were removed by soil denitrification, indicating that anthropogenic N applications could drive substantial increase of N2O emission, an intermediate of the denitrification process.

Lee, M.; Malyshev, S.; Shevliakova, E.; Milly, P. C. D.; Jaffé, P. R.

2014-10-01

384

An economic analysis of land use alternatives on CRP land trees after the CRP contracts expire in east Texas  

E-print Network

rotation length of the tree stand. The real discounted revenues of the land use alternatives, based in 1993, are compared on a per-acre basis. The results indicate that retaining trees on post-CRP land is a better option than reverting land to corn, cotton...

Arekere, Marigowda Dhananjaya

1996-01-01

385

Urban land use of the Sao Paulo metropolitan area by automatic analysis of LANDSAT data  

NASA Technical Reports Server (NTRS)

The separability of urban land use classes in the metropolitan area of Sao Paulo was studied by means of automatic analysis of MSS/LANDSAT digital data. The data were analyzed using the media K and MAXVER classification algorithms. The land use classes obtained were: CBD/vertical growth area, residential area, mixed area, industrial area, embankment area type 1, embankment area type 2, dense vegetation area and sparse vegetation area. The spectral analysis of representative samples of urban land use classes was done using the "Single Cell" analysis option. The classes CBD/vertical growth area, residential area and embankment area type 2 showed better spectral separability when compared to the other classes.

Parada, N. D. J. (principal investigator); Niero, M.; Foresti, C.

1983-01-01

386

Relations Among Geology, Physiography, Land Use, and Stream Habitat Conditions in the Buffalo and Current River Systems, Missouri and Arkansas  

USGS Publications Warehouse

This study investigated links between drainage-basin characteristics and stream habitat conditions in the Buffalo National River, Arkansas and the Ozark National Scenic Riverways, Missouri. It was designed as an associative study - the two parks were divided into their principle tributary drainage basins and then basin-scale and stream-habitat data sets were gathered and compared between them. Analyses explored the relative influence of different drainage-basin characteristics on stream habitat conditions. They also investigated whether a relation between land use and stream characteristics could be detected after accounting for geologic and physiographic differences among drainage basins. Data were collected for three spatial scales: tributary drainage basins, tributary stream reaches, and main-stem river segments of the Current and Buffalo Rivers. Tributary drainage-basin characteristics were inventoried using a Geographic Information System (GIS) and included aspects of drainage-basin physiography, geology, and land use. Reach-scale habitat surveys measured channel longitudinal and cross-sectional geometry, substrate particle size and embeddedness, and indicators of channel stability. Segment-scale aerial-photo based inventories measured gravel-bar area, an indicator of coarse sediment load, along main-stem rivers. Relations within and among data sets from each spatial scale were investigated using correlation analysis and multiple linear regression. Study basins encompassed physiographically distinct regions of the Ozarks. The Buffalo River system drains parts of the sandstone-dominated Boston Mountains and of the carbonate-dominated Springfield and Salem Plateaus. The Current River system is within the Salem Plateau. Analyses of drainage-basin variables highlighted the importance of these physiographic differences and demonstrated links among geology, physiography, and land-use patterns. Buffalo River tributaries have greater relief, steeper slopes, and more streamside bluffs than the Current River tributaries. Land use patterns in both river systems correlate with physiography - cleared land area is negatively associated with drainage-basin average slope. Both river systems are dominantly forested (0-35 per-cent cleared land), however, the potential for landscape disturbance may be greater in the Buffalo River system where a larger proportion of cleared land occurs on steep slopes (>15 degrees). When all drainage basins are grouped together, reach-scale channel characteristics show the strongest relations with drainage-basin physiography. Bankfull channel geometry and residual pool dimensions are positively correlated with drainage area and topographic relief variables. After accounting for differences in drainage area, channel dimensions in Buffalo River tributaries tend to be larger than in Current River tributaries. This trend is consistent with the flashy runoff and large storm flows that can be generated in rugged, sandstone-dominate terrain. Substrate particle size is also most strongly associated with physiography; particle size is positively correlated with topographic relief variables. When tributaries are subset by river system, relations with geology and land use variables become apparent. Buffalo River tributaries with larger proportions of carbonate bedrock and cleared land area have shallower channels, better-sorted, gravel-rich substrate, and more eroding banks than those with little cleared land and abundant sandstone bedrock. Gravel-bar area on the Buffalo River main stem was also larger within 1-km of carbonate-rich tributary junctions. Because geology and cleared land are themselves correlated, relations with anthropogenic and natural factors could often not be separated. Channel characteristics in the Current River system show stronger associations with physiography than with land use. Channels are shallower and have finer substrates in the less rugged, karst-rich, western basins than in the

Panfil, Maria S.; Jacobson, Robert B.

2001-01-01

387

Landing performance of an air cushion landing system installed on a 1/10-scale dynamic model on the C-8 Buffalo airplane  

NASA Technical Reports Server (NTRS)

An experimental study was conducted to evaluate the landing behavior of a 1/10-scale dynamic model of the C-8 Buffalo airplane equipped with an air-cushion landing system (ACLS) on a variety of surfaces including both calm and rough water and a smooth hard surface. Taxi runs were made on the hard surface over several obstacles. Landings were made with the model at various pitch and roll attitudes and vertical velocities and at one nominal horizontal velocity. Data from the landings include time histories of the trunk and air-cushion pressures and accelerations at selected locations on the model.

Thompson, W. C.

1973-01-01

388

Hydration of the lower stratosphere by ice crystal geysers over land convective systems  

E-print Network

The possible impact of deep convective overshooting over land has been explored by six simultaneous soundings of water vapour, particles and ozone in the lower stratosphere next to Mesoscale Convective Systems (MCSs) during ...

Khaykin, S.

389

78 FR 33705 - Postdecisional Administrative Review Process for Occupancy or Use of National Forest System Lands...  

Federal Register 2010, 2011, 2012, 2013, 2014

...DEPARTMENT OF AGRICULTURE Forest Service 36 CFR Parts 212, 214, 215, 222...Review Process for Occupancy or Use of National Forest System Lands and Resources AGENCY: USDA, Forest Service. ACTION: Final...

2013-06-05

390

Design of an Automatic Landing System for the Meridian UAV using Fuzzy Logic  

E-print Network

This document describes the design of an automatic landing system for the Meridian unmanned aerial vehicle (UAV) in development for glacial ice research. The Center for Remote Sensing of Ice Sheets (CReSIS), established by the National Science...

Royer, David Andrew

2010-04-22

391

Developing better reservoir models for Early Palaeozoic, (pre land plants), mixed continental/marine depositional systems  

E-print Network

Developing better reservoir models for Early Palaeozoic, (pre land plants), mixed continental/marine depositional systems: improving reservoir characterisation and architectural input Supervisory Team Professor George (University of Western Australia Overview Pre-Late Silurian reservoirs, which hold significant

Henderson, Gideon

392

Estimating model and observation error covariance information for land data assimilation systems  

Technology Transfer Automated Retrieval System (TEKTRAN)

In order to operate efficiently, data assimilation systems require accurate assumptions concerning the statistical magnitude and cross-correlation structure of error in model forecasts and assimilated observations. Such information is seldom available for the operational implementation of land data ...

393

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

PubMed

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

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

2013-01-01

394

Enhanced Flight Vision Systems and Synthetic Vision Systems for NextGen Approach and Landing Operations  

NASA Technical Reports Server (NTRS)

Synthetic Vision Systems and Enhanced Flight Vision System (SVS/EFVS) technologies have the potential to provide additional margins of safety for aircrew performance and enable operational improvements for low visibility operations in the terminal area environment with equivalent efficiency as visual operations. To meet this potential, research is needed for effective technology development and implementation of regulatory standards and design guidance to support introduction and use of SVS/EFVS advanced cockpit vision technologies in Next Generation Air Transportation System (NextGen) operations. A fixed-base pilot-in-the-loop simulation test was conducted at NASA Langley Research Center that evaluated the use of SVS/EFVS in NextGen low visibility approach and landing operations. Twelve crews flew approach and landing operations in a simulated NextGen Chicago O'Hare environment. Various scenarios tested the potential for using EFVS to conduct approach, landing, and roll-out operations in visibility as low as 1000 feet runway visual range (RVR). Also, SVS was tested to evaluate the potential for lowering decision heights (DH) on certain instrument approach procedures below what can be flown today. Expanding the portion of the visual segment in which EFVS can be used in lieu of natural vision from 100 feet above the touchdown zone elevation to touchdown and rollout in visibilities as low as 1000 feet RVR appears to be viable as touchdown performance was acceptable without any apparent workload penalties. A lower DH of 150 feet and/or possibly reduced visibility minima using SVS appears to be viable when implemented on a Head-Up Display, but the landing data suggests further study for head-down implementations.

Kramer, Lynda J.; Bailey, Randall E.; Ellis, Kyle K. E.; Williams, Steven P.; Arthur, Jarvis J., III; Prinzel, Lawrence J., III; Shelton, Kevin J.

2013-01-01

395

INTEGRATED LAND-USE SYSTEMS: ASSESSMENT OF PROMISING AGROFOREST AND ALTERNATIVE LAND-USE PRACTICES TO ENHANCE CARBON CONSERVATION AND SEQUESTRATION  

EPA Science Inventory

Degraded or sub-standard soils and marginal lands occupy a significant proportion of boreal, temperate and tropical biomes. anagement of these lands with a wide range of existing, site-specific, integrated, agroforest systems represents a significant global opportunity to reduce ...

396

Fuzzy Logic Based Approach to Design of Autonomous Landing System for Unmanned Aerial Vehicles  

Microsoft Academic Search

This paper is concerned with autonomous flight of UAVs and proposes a fuzzy logic based autonomous flight and landing system\\u000a controller. Besides three fuzzy logic controllers which are developed for autonomous navigation for UAVs in a previous work\\u000a as fuzzy logic based autonomous mission control blocks, three more fuzzy logic modules are developed under the main landing\\u000a system for the

Omer Cetin; Sefer Kurnaz; Okyay Kaynak

2011-01-01

397

The impact of the Microwave landing system (MLS) on runway capacity at British regional airports  

Microsoft Academic Search

The Microwave Landing System (MLS) has the ability to support curved and steep angle approaches and provides improved precision approach guidance when compared with the current Instrument Landing System (ILS).These MLS characteristics produce reduced inter?arrival spacing when compared with ILS procedures and therefore increase runway capacity if the runway occupancy time is not the limiting factor.This paper considers the effect

F. Abdelouahab; N. Ashford

1991-01-01

398

Interaction Relationship between Agricultural Insurance and Transfer of Land Contract Rights Based on Game Analysis of Farmer Selection  

Microsoft Academic Search

In the new stage of rural reform, faced universal transfer of land contract rights, one of the most important tasks of rural system construction is accelerating development of agricultural insurance in China. However, agricultural insurance does not function efficiently enough to accord effective protection to farmers in land contract rights transfer, and agricultural insurance and transfer of land contract rights

Zhaojun Liu

2010-01-01

399

Using soft-systems methods to evaluate the outputs from multi-objective land use planning tools  

E-print Network

Using soft-systems methods to evaluate the outputs from multi-objective land use planning tools K.B. Matthews , K. Buchan , A.R. Sibbald , and Susan Craw The Macaulay Land Use Research Institute, Aberdeen, AB effects on the financial, social and environmental sustainability of land use systems. One approach

Coello, Carlos A. Coello

400

Inertial navigation systems analysis.  

NASA Technical Reports Server (NTRS)

This volume offers the avionic systems engineer a fundamental exposition of the mechanization and error analysis of inertial navigation systems. While the material is applicable to spacecraft and undersea navigation, emphasis is placed upon terrestrial applications on or slightly above the earth's surface. As a result, practical considerations are geared toward those aircraft navigation systems of particular current interest. Extensive use is made of perturbation techniques to develop linearized system equations, whose solutions closely approximate those obtained by nonlinear differential equations. A unified error analysis technique is developed that is applicable to virtually all system configurations. The technique provides a greatly simplified method for comparing the performance of competing system configurations.

Britting, K. R.

1971-01-01

401

Analysis of Land Use Change and Urbanization in the Kucukcekmece Water Basin (Istanbul, Turkey) with Temporal Satellite Data using Remote Sensing and GIS  

PubMed Central

Accurate and timely information about land use and land cover (LULC) and its changes in urban areas are crucial for urban land management decision-making, ecosystem monitoring and urban planning. Also, monitoring and representation of urban sprawl and its effects on the LULC patterns and hydrological processes of an urbanized watershed is an essential part of water resource planning and management. This paper presents an image analysis study using multi temporal digital satellite imagery of LULC and changes in the Kucukcekmece Watershed (Metropolitan Istanbul, Turkey) from 1992 to 2006. The Kucukcekmece Basin includes portions of the Kucukcekmece District within the municipality of Istanbul so it faces a dramatic urbanization. An urban monitoring analysis approach was first used to implement a land cover classification. A change detection method controlled with ground truth information was then used to determine changes in land cover. During the study period, the variability and magnitude of hydrological components based on land-use patterns were cumulatively influenced by urban sprawl in the watershed. The proposed approach, which uses a combination of Remote Sensing (RS) and Geographical Information System (GIS) techniques, is an effective tool that enhances land-use monitoring, planning, and management of urbanized watersheds.

Coskun, H. Gonca; Alganci, Ugur; Usta, Gokce

2008-01-01

402

L A N D U S E S / S Y S T E M S & O B J E C T I V E S | EXISTING AND PROPOSED LAND USES Land Uses/Systems &  

E-print Network

L A N D U S E S / S Y S T E M S & O B J E C T I V E S | EXISTING AND PROPOSED LAND USES Land Uses/Systems & Objectives EXISTING AND PROPOSED LAND USES The 2003 LRDP identifies 16 land use categories covering a range of built environ- ments and open lands. The Existing Land Use diagram in this section presents cur- rent

California at Davis, University of

403

Propagation measurements for an Australian land mobile-satellite system  

Microsoft Academic Search

Plans to introduce Land Mobile-Satellite Services (LMSS) at L-band in 1991\\/92 are discussed. Although it is known that attenuation due to roadside trees is significant it is not well quantified. This paper describes measurements of attenuation statistics using a helicopter and an instrumented van. Results are given for two different tree densities, for evaluation angles of 30, 45, and 60

A. J. Bundrock; R. A. Harvey

1989-01-01

404

Marine algae and land plants share conserved phytochrome signaling systems  

PubMed Central

Phytochrome photosensors control a vast gene network in streptophyte plants, acting as master regulators of diverse growth and developmental processes throughout the life cycle. In contrast with their absence in known chlorophyte algal genomes and most sequenced prasinophyte algal genomes, a phytochrome is found in Micromonas pusilla, a widely distributed marine picoprasinophyte (<2 µm cell diameter). Together with phytochromes identified from other prasinophyte lineages, we establish that prasinophyte and streptophyte phytochromes share core light-input and signaling-output domain architectures except for the loss of C-terminal response regulator receiver domains in the streptophyte phytochrome lineage. Phylogenetic reconstructions robustly support the presence of phytochrome in the common progenitor of green algae and land plants. These analyses reveal a monophyletic clade containing streptophyte, prasinophyte, cryptophyte, and glaucophyte phytochromes implying an origin in the eukaryotic ancestor of the Archaeplastida. Transcriptomic measurements reveal diurnal regulation of phytochrome and bilin chromophore biosynthetic genes in Micromonas. Expression of these genes precedes both light-mediated phytochrome redistribution from the cytoplasm to the nucleus and increased expression of photosynthesis-associated genes. Prasinophyte phytochromes perceive wavelengths of light transmitted farther through seawater than the red/far-red light sensed by land plant phytochromes. Prasinophyte phytochromes also retain light-regulated histidine kinase activity lost in the streptophyte phytochrome lineage. Our studies demonstrate that light-mediated nuclear translocation of phytochrome predates the emergence of land plants and likely represents a widespread signaling mechanism in unicellular algae. PMID:25267653

Duanmu, Deqiang; Bachy, Charles; Sudek, Sebastian; Wong, Chee-Hong; Jiménez, Valeria; Rockwell, Nathan C.; Martin, Shelley S.; Ngan, Chew Yee; Reistetter, Emily N.; van Baren, Marijke J.; Price, Dana C.; Wei, Chia-Lin; Reyes-Prieto, Adrian; Lagarias, J. Clark; Worden, Alexandra Z.

2014-01-01

405

Tracing the source and fate of nitrate in contemporary mixed land-use surface water systems  

NASA Astrophysics Data System (ADS)

Nitrogenous fertilizers increase agricultural productivity, ultimately feeding the planet. Yet, it is possible to have too much of a good thing, and nitrogen is no exception. When in excess nitrogen has been shown to accelerate eutrophication of water bodies, and act as a chronic toxin (e.g. methemoglobinemia). As land-use intensity continues to rise in response to increases in agricultural productivity, the risk of adverse effects of nitrogen loading on surface water bodies will also increase. Stable isotope proxies are potential tracers of nitrate, the most common nitrogenous phase in surface waters. Applying stable isotope proxies therefore presents an opportunity to identify and manage sources of excess nitrogen before aquatic systems are severely degraded. However, the heterogeneous nature of potential pollution sources themselves, and their distribution with a modified catchment network, make understanding this issue highly complex. The Banks Peninsula, an eroded late tertiary volcanic complex located on the east coast of the South Island New Zealand, presents a unique opportunity to study and understand the sources and fates of nitrate within streams in a contemporary mixed land-use setting. Within this small geographic area there a variety of agricultural activities are practiced, including: heavily fertilized golf courses; stands of regenerating native forest; and areas of fallow gorse (Ulex europaeus; a invasive N-fixing shrub). Each of these landuse classes has its own unique nitrogen budget. Multivariate analysis was used on stream nitrate concentrations to reveal that stream reaches dominated by gorse had significantly higher nitrate concentrations than other land-use classes. Nitrate ?15N & ?18O data from these sites show strong covariance, plotting along a distinct fractionation line (r2 = 0.96). This finding facilitates interpretation of what processes are controlling nitrate concentration within these systems. Further, complementary aquatic foodweb ?15N ?13C analyses of multiple species in various trophic positions allow for a unique, holistic insight in to the fate of gorse-derived nitrate at an ecosystem level. We present here physicochemical and stable isotopic data from a variety of aqueous and aquatic foodweb components. Data is generated using emerging and established analytical techniques, in order to explore links between foodweb ecology, ecosystem function, and fate and transport of excess nitrate along longitudinal gradients of mixed land-use catchments.

Stewart, S. D.; Young, M. B.; Horton, T. W.; Harding, J. S.

2011-12-01

406

Watershed scale environmental sustainability analysis of biofuel production in changing land use and climate scenarios  

NASA Astrophysics Data System (ADS)

One of the grand challenges in meeting the US biofuel goal is producing large quantities of cellulosic biofeedstock materials for the production of biofuels in an environmentally sustainable and economically viable manner. The possible land use and land management practice changes induce concerns over the environmental impacts of these bioenergy crop production scenarios both in terms of water availability and water quality, and these impacts may be exacerbated by climate variability and change. This study aims to evaluate environmental sustainability of various plausible land and crop management scenarios for biofuel production under changing climate scenarios for a Midwest US watershed. The study considers twelve environmental sustainability indicators related hydrology and water quality with thirteen plausible biofuels scenarios in the watershed under nine climate change scenarios. The land use change scenarios for evaluation includes, (1) bioenergy crops in highly erodible soils (3) bioenergy crops in low row crop productive fields (marginal lands); (3) bioenergy crops in pasture and range land use areas and (4) combinations of these scenarios. Future climate data bias corrected and downscaled to daily values from the World Climate Research Programme's (WCRP's) Coupled Model Intercomparison Project phase 3 (CMIP3) multi-model dataset were used in this study. The distributed hydrological model SWAT (Soil and Water Assessment Tool) was used to simulate bioenergy crops growth, hydrology and water quality. The watershed scale sustainability analysis was done in Wildcat Creek basin, which is located in North-Central Indiana, USA.

RAJ, C.; Chaubey, I.; Cherkauer, K. A.; Brouder, S. M.; Volenec, J. J.

2013-12-01

407

Modeling regional aquifer-system compaction and land subsidence in Yunlin County, Taiwan  

NASA Astrophysics Data System (ADS)

Yunlin is a county in central Taiwan that is home to several major economic development projects. Extracting groundwater has caused large-scale land subsidence in Yunlin, with the largest cumulative subsidence being 135 cm over 1992-2010. A multi-sensor monitoring system consisting of continuous GPS stations (CGPSs), a leveling network, gravity network, 300 m-deep multi-layer compaction monitoring wells and groundwater wells is deployed to monitor land subsidence and its mechanism in Yunlin. GPS data at CGPS station HWES in Huwei Township of Yunlin show a cumulative subsidence of 19.9 cm over May 2007- October 2011. Data from a nearby monitoring well show that the subsidence is caused by compactions occurring mainly at aquifers 2, 3 and 4. An analysis of subsidence and compaction at HWES suggests that the compaction is ongoing at depths > 300 m. Four hydrogeological parameters of the three sediment layers in Huwei, i.e., vertical hydraulic conductivity, elastic skeletal specific storage, inelastic skeletal specific storage, and the initial maximum preconsolidation stress, in the one-dimensional compaction model COMPAC, are estimated using the genetic algorithm. With the parameters, COMPAC predicts compactions to an accuracy consistent with in situ measurements, and the root mean square error are below 5mm. The result provides a key reference for water management in central Taiwan.

Hung, W.-C.; Hwang, C. W.; Kuo, C. L.; Yeh, T. K.

2012-04-01

408

Simulation study of two VTOL control/display systems in IMC approach and landing  

NASA Technical Reports Server (NTRS)

Both systems had full attitude command; the more complex system (Type 1) also had translational velocity command. The systems were applied to existing models of a VTOL lift-fan transport and the AV-8A Harrier. Simulated landings were made on a model of a DD963 Spruance-class destroyer. It was concluded that acceptable transitions and vertical landings can be performed, using the Type 1 system, in free-air turbulence up to 2.5 m/sec and sea state 6 and, using the Type 2 system, in free-air turbulence up to 1.5 m/sec and sea state 4.

Merrick, V. K.

1981-01-01

409

The Met Office Coupled Atmosphere/Land/Ocean/Sea-Ice Data Assimilation System  

NASA Astrophysics Data System (ADS)

The Met Office has developed a weakly-coupled data assimilation (DA) system using the global coupled model HADGEM3 (Hadley Centre Global Environment Model, version 3). This model combines the atmospheric model UM (Unified Model) at 60 km horizontal resolution on 85 vertical levels, the ocean model NEMO (Nucleus for European Modeling of the Ocean) at 25 km (at the equator) horizontal resolution on 75 vertical levels, and the sea-ice model CICE at the same resolution as NEMO. The atmosphere and the ocean/sea-ice fields are coupled every 1-hour using the OASIS coupler. The coupled model is corrected using two separate 6-hour window data assimilation systems: a 4D-Var for the atmosphere with associated soil moisture content nudging and snow analysis schemes on the one hand, and a 3D-Var FGAT for the ocean and sea-ice on the other hand. The background information in the DA systems comes from a previous 6-hour forecast of the coupled model. To show the impact of coupled DA, one-month experiments have been carried out, including 1) a full atmosphere/land/ocean/sea-ice coupled DA run, 2) an atmosphere-only run forced by OSTIA SSTs and sea-ice with atmosphere and land DA, and 3) an ocean-only run forced by atmospheric fields from run 2 with ocean and sea-ice DA. In addition, 5-day forecast runs, started twice a day, have been produced from initial conditions generated by either run 1 or a combination of runs 2 and 3. The different results have been compared to each other and, whenever possible, to other references such as the Met Office atmosphere and ocean operational analyses or the OSTIA data. These all show the coupled DA system functioning well. Evidence of imbalances and initialisation shocks has also been looked for.

Lea, Daniel; Mirouze, Isabelle; Martin, Matthew; Hines, Adrian; Guiavarch, Catherine; Shelly, Ann

2014-05-01

410

Covariance Analysis Tool (G-CAT) for Computing Ascent, Descent, and Landing Errors  

NASA Technical Reports Server (NTRS)

G-CAT is a covariance analysis tool that enables fast and accurate computation of error ellipses for descent, landing, ascent, and rendezvous scenarios, and quantifies knowledge error contributions needed for error budgeting purposes. Because GCAT supports hardware/system trade studies in spacecraft and mission design, it is useful in both early and late mission/ proposal phases where Monte Carlo simulation capability is not mature, Monte Carlo simulation takes too long to run, and/or there is a need to perform multiple parametric system design trades that would require an unwieldy number of Monte Carlo runs. G-CAT is formulated as a variable-order square-root linearized Kalman filter (LKF), typically using over 120 filter states. An important property of G-CAT is that it is based on a 6-DOF (degrees of freedom) formulation that completely captures the combined effects of both attitude and translation errors on the propagated trajectories. This ensures its accuracy for guidance, navigation, and control (GN&C) analysis. G-CAT provides the desired fast turnaround analysis needed for error budgeting in support of mission concept formulations, design trade studies, and proposal development efforts. The main usefulness of a covariance analysis tool such as G-CAT is its ability to calculate the performance envelope directly from a single run. This is in sharp contrast to running thousands of simulations to obtain similar information using Monte Carlo methods. It does this by propagating the "statistics" of the overall design, rather than simulating individual trajectories. G-CAT supports applications to lunar, planetary, and small body missions. It characterizes onboard knowledge propagation errors associated with inertial measurement unit (IMU) errors (gyro and accelerometer), gravity errors/dispersions (spherical harmonics, masscons), and radar errors (multiple altimeter beams, multiple Doppler velocimeter beams). G-CAT is a standalone MATLAB- based tool intended to run on any engineer's desktop computer.

Boussalis, Dhemetrios; Bayard, David S.

2013-01-01

411

Modeling the Behaviour of an Advanced Material Based Smart Landing Gear System for Aerospace Vehicles  

SciTech Connect

The last two decades have seen a substantial rise in the use of advanced materials such as polymer composites for aerospace structural applications. In more recent years there has been a concerted effort to integrate materials, which mimic biological functions (referred to as smart materials) with polymeric composites. Prominent among smart materials are shape memory alloys, which possess both actuating and sensory functions that can be realized simultaneously. The proper characterization and modeling of advanced and smart materials holds the key to the design and development of efficient smart devices/systems. This paper focuses on the material characterization; modeling and validation of the model in relation to the development of a Shape Memory Alloy (SMA) based smart landing gear (with high energy dissipation features) for a semi rigid radio controlled airship (RC-blimp). The Super Elastic (SE) SMA element is configured in such a way that it is forced into a tensile mode of high elastic deformation. The smart landing gear comprises of a landing beam, an arch and a super elastic Nickel-Titanium (Ni-Ti) SMA element. The landing gear is primarily made of polymer carbon composites, which possess high specific stiffness and high specific strength compared to conventional materials, and are therefore ideally suited for the design and development of an efficient skid landing gear system with good energy dissipation characteristics. The development of the smart landing gear in relation to a conventional metal landing gear design is also dealt with.

Varughese, Byji; Dayananda, G. N.; Rao, M. Subba [National Aerospace Laboratories, P.B. No: 1779, Airport Road, Bangalore-560017 (India)

2008-07-29

412

Modeling the Behaviour of an Advanced Material Based Smart Landing Gear System for Aerospace Vehicles  

NASA Astrophysics Data System (ADS)

The last two decades have seen a substantial rise in the use of advanced materials such as polymer composites for aerospace structural applications. In more recent years there has been a concerted effort to integrate materials, which mimic biological functions (referred to as smart materials) with polymeric composites. Prominent among smart materials are shape memory alloys, which possess both actuating and sensory functions that can be realized simultaneously. The proper characterization and modeling of advanced and smart materials holds the key to the design and development of efficient smart devices/systems. This paper focuses on the material characterization; modeling and validation of the model in relation to the development of a Shape Memory Alloy (SMA) based smart landing gear (with high energy dissipation features) for a semi rigid radio controlled airship (RC-blimp). The Super Elastic (SE) SMA element is configured in such a way that it is forced into a tensile mode of high elastic deformation. The smart landing gear comprises of a landing beam, an arch and a super elastic Nickel-Titanium (Ni-Ti) SMA element. The landing gear is primarily made of polymer carbon composites, which possess high specific stiffness and high specific strength compared to conventional materials, and are therefore ideally suited for the design and development of an efficient skid landing gear system with good energy dissipation characteristics. The development of the smart landing gear in relation to a conventional metal landing gear design is also dealt with.

Varughese, Byji; Dayananda, G. N.; Rao, M. Subba

2008-07-01

413

Land-use poverty traps identified in shifting cultivation systems shape long-term tropical forest cover  

PubMed Central

In this article we illustrate how fine-grained longitudinal analyses of land holding and land use among forest peasant households in an Amazonian village can enrich our understanding of the poverty/land cover nexus. We examine the dynamic links in shifting cultivation systems among asset poverty, land use, and land cover in a community where poverty is persistent and primary forests have been replaced over time—with community enclosure—by secondary forests (i.e., fallows), orchards, and crop land. Land cover change is assessed using aerial photographs/satellite imagery from 1965 to 2007. Household and plot level data are used to track land holding, portfolios, and use as well as land cover over the past 30 y, with particular attention to forest status (type and age). Our analyses find evidence for two important types of “land-use” poverty traps—a “subsistence crop” trap and a “short fallow” trap—and indicate that the initial conditions of land holding by forest peasants have long-term effects on future forest cover and household welfare. These findings suggest a new mechanism driving poverty traps: insufficient initial land holdings induce land use patterns that trap households in low agricultural productivity. Path dependency in the evolution of household land portfolios and land use strategies strongly influences not only the wellbeing of forest people but also the dynamics of tropical deforestation and secondary forest regrowth. PMID:21873179

Coomes, Oliver T.; Takasaki, Yoshito; Rhemtulla, Jeanine M.

2011-01-01

414

Land-use poverty traps identified in shifting cultivation systems shape long-term tropical forest cover.  

PubMed

In this article we illustrate how fine-grained longitudinal analyses of land holding and land use among forest peasant households in an Amazonian village can enrich our understanding of the poverty/land cover nexus. We examine the dynamic links in shifting cultivation systems among asset poverty, land use, and land cover in a community where poverty is persistent and primary forests have been replaced over time--with community enclosure--by secondary forests (i.e., fallows), orchards, and crop land. Land cover change is assessed using aerial photographs/satellite imagery from 1965 to 2007. Household and plot level data are used to track land holding, portfolios, and use as well as land cover over the past 30 y, with particular attention to forest status (type and age). Our analyses find evidence for two important types of "land-use" poverty traps--a "subsistence crop" trap and a "short fallow" trap--and indicate that the initial conditions of land holding by forest peasants have long-term effects on future forest cover and household welfare. These findings suggest a new mechanism driving poverty traps: insufficient initial land holdings induce land use patterns that trap households in low agricultural productivity. Path dependency in the evolution of household land portfolios and land use strategies strongly influences not only the wellbeing of forest people but also the dynamics of tropical deforestation and secondary forest regrowth. PMID:21873179

Coomes, Oliver T; Takasaki, Yoshito; Rhemtulla, Jeanine M

2011-08-23

415

Integration of Data Assimilation, Stochastic Optimization and Uncertainty Modeling within NASA's Land Information System (LIS)  

NASA Astrophysics Data System (ADS)

Recent advances in information systems technology have significantly improved our ability to fully exploit the information content of remote sensing data. In this talk, we discuss a range of applications for the optimization and uncertainty tools recently incorporated into the NASA Land Information System (LIS) to address this challenge. LIS is a high-resolution, high-performance, land surface modeling and data assimilation system that supports a wide range of land surface research and applications. The applications of the new optimization and uncertainty tools involve several LIS land-coupled models, including the Weather Research and Forecasting Model (WRF), models of land microwave emission (the Soil Moisture and Ocean Salinity (SMOS) Community Microwave Emission Model (CMEM)), radiative transfer (Joint Center for Satellite Data Assimilation's Community Radiative Transfer Model (CRTM)), landslide and streamflow simulation. The impact of parameter estimation on land surface modeling is investigated for a range of studies, including soil moisture modeling in the Walnut Gulch experimental watershed, land data assimilation over the continental United States, and coupled land-atmosphere forecasts using WRF for the Southern Great Plains. In addition, the uncertainty in the outputs of such coupled systems is investigated. The uncertainty methods include Monte Carlo for propagating parameter uncertainties and model errors as well as Markov chain Monte Carlo methods that enable the updating of parameter uncertainties with remote sensing data. The tradeoffs between uncertainty estimation and parameter estimation are also highlighted. Finally, remaining challenges for the development of information systems of this kind are identified, including challenges in their use as part of mission simulation experiments.

Harrison, K.; Peters-Lidard, C. D.; Kumar, S.; Santanello, J. A.; Kirschbaum, D. B.

2011-12-01

416

76 FR 1629 - Public Land Order No. 7757; Withdrawal of National Forest System Land for the Big Ice Cave; Montana  

Federal Register 2010, 2011, 2012, 2013, 2014

...Sandra Ward, Bureau of Land Management, Montana State Office, 5001 Southgate Drive, Billings, Montana 59101, 406-896-5052. SUPPLEMENTARY INFORMATION: The Forest Service will manage the land to protect the Big Ice Cave, its subterranean water...

2011-01-11

417

Spatio-temporal pattern analysis of land use/cover change trajectories in Xihe watershed  

NASA Astrophysics Data System (ADS)

Human-induced land use/cover change has been considered to be one of the most important parts of global environmental changes. In loess hilly and gully regions, to prevent soil loss and achieve better ecological environments, soil conservation measures have been taken during the past decades. The main objective of this study is to quantify the spatio-temporal variability of land use/cover change spatial patterns and make preliminary estimation of the role of human activity in the environmental change in Xihe watershed, Gansu Province, China. To achieve this objective, the methodology was developed in two different aspects, that is, (1) analysis of change patterns by binary image of change trajectories overlaid with different natural geographic factors, in which Relative Change Intensity (RCI) metric was established and used to make comparisons, and (2) analysis based on pattern metrics of main trajectories in the study area. Multi-source and multi-temporal Remote Sensing (RS) images (including Landsat ETM+ (30 June 2001), SPOT imagery (21 November 2003 and 5 May 2008) and CBERS02 CCD (5 June 2006)) were used due to the constraints of the availability of remotely sensed data. First, they were used to extract land use/cover types of each time node by object-oriented classification method. Classification results were then utilized in the trajectory analysis of land use/cover changes through the given four time nodes. Trajectories at every pixel were acquired to trace the history of land use/cover change for every location in the study area. Landscape metrics of trajectories were then analyzed to detect the change characteristics in time and space through the given time series. Analysis showed that most land use/cover changes were caused by human activities, most of which, under the direction of local government, had mainly led to virtuous change on the ecological environments. While, on the contrary, about one quarter of human-induced changes were vicious ones. Analysis through overlaying binary image of change trajectories with natural factors can efficiently show the spatio-temporal distribution characteristics of land use/cover change patterns. It is found that in the study area RCI of land use/cover changes is related to the distance to the river line. And there is a certain correlation between RCI and slope grades. However, no obvious correlation exists between RCI and aspect grades.

Wang, Dongchuan; Gong, Jianhua; Chen, Liding; Zhang, Lihui; Song, Yiquan; Yue, Yujuan

2012-02-01

418

Spatial assessment of soil properties for agricultural land using remotely sensed imagery, relief analysis and GIS  

Microsoft Academic Search

This paper presents a methodological framework and has applications in sustainable land use planning and the management of agroecosystems. On examples of a mountain range in Germany airborne remote sensing and digital relief analysis have been used to improve the inventory of soil heterogeneity and to asses its impact on crop growth. A bioindicative model concept has been developed, based

Thomas M. Selige

1997-01-01

419

Analysis of badlands: coupling of tectonic and land surface processes in the Pyrenees of Spain  

E-print Network

Analysis of badlands: coupling of tectonic and land surface processes in the Pyrenees of Spain MSc to rainstorms. In north-east Spain, sediment from rapidly eroding badlands has significantly reduced reservoir-funded research consortium (SESAM II) with partners at the University of Lleida, Spain

Baer, Christian

420

SPECTRAL ANALYSIS OF COASTAL VEGETATION AND LAND COVER USING AISA+HYPERSPECTRAL DATA  

Technology Transfer Automated Retrieval System (TEKTRAN)

This paper describes spectral analysis of several coastal land cover types on South Padre Island, Texas, using AISA+hyperspectral remote sensing data. AISA+hyperspectral data (1.5 meter) were acquired throughout the area on 9 March 2005. Data over mangrove areas were converted to percent reflecta...

421

Chemical analysis of mucus from certain land snails under Egyptian conditions  

Microsoft Academic Search

The present investigation was carried out to study the chemical analysis of the mucus of three common land snails, Eobania vermiculata, Theba pisana and Monacha obstructa, and identification of the chemical compositions by using GC-MS. Results revealed that several variations in composition were observed between all species. Oxime, methoxy-phenyl and cyclotrisiloxane, hexamethyl were major components found that in three species,

A. A. A. Sallam; S. A. El-Massry; I. N. Nasr

2009-01-01

422

A conceptual ground processing system for operational land remote sensing satellites  

Microsoft Academic Search

A nonexperimental, or 'operational,' land remote-sensing satellite system will become a reality during this decade. The spatial resolution and number of spectral bands of such a system could exceed those of the current Landsat systems and result in a data stream as large as 10 to the 12th bits per day, transmitted at rates as high as 150 million bits

P. F. Holkenbrink; D. E. Ulmer; G. H. Landis; B. P. Bauer

1980-01-01

423

Parametrized Verification of Distributed Cyber-Physical Systems: An Aircraft Landing Protocol Case Study  

E-print Network

and automatically verify the key safety property of the protocol regardless of the number of aircraft in the systemParametrized Verification of Distributed Cyber-Physical Systems: An Aircraft Landing Protocol Case called the Small Aircraft Transportation System (SATS). Each aircraft is modeled as a timed automaton

Liberzon, Daniel

424

High-Resolution Land Data Assimilation System and its Application to NWP  

Microsoft Academic Search

A High-Resolution Land Data Assimilation System (HRLDAS) has been developed at the National Center for Atmospheric Research. It uses observed hourly precipitation and surface solar downward radiation to drive, in offline mode, a land surface model (the so-named OSULSM) to simulate long-term evolution of soil state including soil moisture and temperature. The advantage of HRLDAS is its use of 1-km

K. Manning; F. Chen

2003-01-01

425

Lateral control system design for VTOL landing on a DD963 in high sea states. M.S. Thesis  

NASA Technical Reports Server (NTRS)

The problem of designing lateral control systems for the safe landing of VTOL aircraft on small ships is addressed. A ship model is derived. The issues of estimation and prediction of ship motions are discussed, using optimal linear linear estimation techniques. The roll motion is the most important of the lateral motions, and it is found that it can be predicted for up to 10 seconds in perfect conditions. The automatic landing of the VTOL aircraft is considered, and a lateral controller, defined as a ship motion tracker, is designed, using optimal control techniqes. The tradeoffs between the tracking errors and the control authority are obtained. The important couplings between the lateral motions and controls are demonstrated, and it is shown that the adverse couplings between the sway and the roll motion at the landing pad are significant constraints in the tracking of the lateral ship motions. The robustness of the control system, including the optimal estimator, is studied, using the singular values analysis. Through a robustification procedure, a robust control system is obtained, and the usefulness of the singular values to define stability margins that take into account general types of unstructured modelling errors is demonstrated. The minimal destabilizing perturbations indicated by the singular values analysis are interpreted and related to the multivariable Nyquist diagrams.

Bodson, M.

1982-01-01

426

Exposure Analysis Modeling System  

EPA Science Inventory

The Exposure Analysis Modeling System (EXAMS) is an interactive software application for formulating aquatic ecosystem models and evaluating the fate, transport, and exposure concentrations of synthetic organic chemicals including pesticides, industrial materials, and leachates f...

427

Soil food web properties explain ecosystem services across European land use systems  

PubMed Central

Intensive land use reduces the diversity and abundance of many soil biota, with consequences for the processes that they govern and the ecosystem services that these processes underpin. Relationships between soil biota and ecosystem processes have mostly been found in laboratory experiments and rarely are found in the field. Here, we quantified, across four countries of contrasting climatic and soil conditions in Europe, how differences in soil food web composition resulting from land use systems (intensive wheat rotation, extensive rotation, and permanent grassland) influence the functioning of soils and the ecosystem services that they deliver. Intensive wheat rotation consistently reduced the biomass of all components of the soil food web across all countries. Soil food web properties strongly and consistently predicted processes of C and N cycling across land use systems and geographic locations, and they were a better predictor of these processes than land use. Processes of carbon loss increased with soil food web properties that correlated with soil C content, such as earthworm biomass and fungal/bacterial energy channel ratio, and were greatest in permanent grassland. In contrast, processes of N cycling were explained by soil food web properties independent of land use, such as arbuscular mycorrhizal fungi and bacterial channel biomass. Our quantification of the contribution of soil organisms to processes of C and N cycling across land use systems and geographic locations shows that soil biota need to be included in C and N cycling models and highlights the need to map and conserve soil biodiversity across the world. PMID:23940339

de Vries, Franciska T.; Thébault, Elisa; Liiri, Mira; Birkhofer, Klaus; Tsiafouli, Maria A.; Bjørnlund, Lisa; Bracht Jørgensen, Helene; Brady, Mark Vincent; Christensen, Søren; de Ruiter, Peter C.; d’Hertefeldt, Tina; Frouz, Jan; Hedlund, Katarina; Hemerik, Lia; Hol, W. H. Gera; Hotes, Stefan; Mortimer, Simon R.; Setälä, Heikki; Sgardelis, Stefanos P.; Uteseny, Karoline; van der Putten, Wim H.; Wolters, Volkmar; Bardgett, Richard D.

2013-01-01

428

Outdoor Recreation on Government Lands in Texas, An Analysis.  

ERIC Educational Resources Information Center

This study represents an inventory of major government, non-urban outdoor recreation programs and facilities in Texas, as well as an indication of visitor use reported by individual agencies. The purpose of the analysis is to illustrate the importance of outdoor recreation in Texas and the contribution of various agencies, rather than to determine…

Reed, David J.; Reid, Leslie M.

429

Land use classification utilizing remote multispectral scanner data and computer analysis techniques  

NASA Technical Reports Server (NTRS)

An airborne multispectral scanner was used to collect the visible and reflective infrared data. A small subdivision near Lafayette, Indiana was selected as the test site for the urban land use study. Multispectral scanner data were collected over the subdivision on May 1, 1970 from an altitude of 915 meters. The data were collected in twelve wavelength bands from 0.40 to 1.00 micrometers by the scanner. The results indicated that computer analysis of multispectral data can be very accurate in classifying and estimating the natural and man-made materials that characterize land uses in an urban scene.

Leblanc, P. N.; Johannsen, C. J.; Yanner, J. E.

1973-01-01

430

Web-GIS Based System for the Management of Objections to a Comprehensive Municipal Land Use Plan  

E-print Network

Web-GIS Based System for the Management of Objections to a Comprehensive Municipal Land Use Plan of a comprehensive municipal land use plan is a long and arduous process that requires great effort from local of urban information and to enable citizens to register objections to the land use plan during

Touriño, Juan

431

A slotted waveguide setup as scaled instrument-landing-system for measuring scattering of an A380 and large objects  

Microsoft Academic Search

At an airport the instrument-landing-system (ILS) provides aircraft on landing approach with both the lateral and vertical guidance to the runway. It is known that the lateral landing course information (localizer) can be disturbed due to reflections on large aircraft taxiing near the runway. Investigating such disturbance scenarios in a scaled setup requires an accurate and flexible modelling of a

R. Geise; J. Schueuer; L. Thiele; K. Notte; T. Beckers; A. Enders

2010-01-01

432

Cost analysis of water and sediment diversions to optimize land building in the Mississippi River delta  

NASA Astrophysics Data System (ADS)

Land loss in the Mississippi River delta caused by subsidence and erosion has resulted in habitat loss and increased exposure of settled areas to storm surge risks. There is debate over the most cost-efficient and geomorphologically feasible projects to build land by river diversions, namely, whether a larger number of small, or a lesser number of large, engineered diversions provide the most efficient outcomes. This study uses an optimization framework to identify portfolios of diversions that are efficient for three general restoration objectives: maximize land built, minimize cost, and minimize water diverted. The framework links the following models: (1) a hydraulic water and sediment diversion model that, for a given structural design for a diversion, estimates the volume of water and sediment diverted; (2) a geomorphological land-building model that estimates the amount of land built over a time period, given the volume of water and sediment; and (3) a statistical model of investment cost as a function of diversion depth and width. An efficient portfolio is found by optimizing one objective subject to constraints on achievement of the other two; then by permuting those constraints, we find distinct portfolios that represent trade-offs among the objectives. Although the analysis explores generic relationships among size, cost, and land building (and thus does not consider specific project proposals or locations), the results demonstrate that large-scale land building (>200 km2) programs that operate over a time span of 50 years require deep diversions because of the enhanced efficiency of sand extraction per unit water. This conclusion applies whether or not there are significant scale economies or diseconomies associated with wider and deeper diversions.

Kenney, Melissa A.; Hobbs, Benjamin F.; Mohrig, David; Huang, Hongtai; Nittrouer, Jeffrey A.; Kim, Wonsuck; Parker, Gary

2013-06-01

433

Land use change and landslide characteristics analysis for community-based disaster mitigation.  

PubMed

On August 8, 2009, Typhoon Morakot brought heavy rain to Taiwan, causing numerous landslides and debris flows in the Taihe village area of Meishan Township, Chiayi County, in south-central Taiwan. In the Taihe land is primary used for agriculture and land use management may be a factor in the area's landslides. This study explores Typhoon Morakot-induced landslides and land use changes between 1999 and 2009 using GIS with the aid of field investigation. Spot 5 satellite images with a resolution of 2.5 m are used for landslide interpretation and manually digitalized in GIS. A statistical analysis for landslide frequency-area distribution was used to identify the landslide characteristics associated with different types of land use. There were 243 landslides with a total area of 2.75 km(2) in the study area. The area is located in intrinsically fragile combinations of sandstone and shale. Typhoon Morakot-induced landslides show a power-law distribution in the study area. Landslides were mainly located in steep slope areas containing natural forest and in areas planted with bamboo, tea, and betel nut. Land covered with natural forest shows the highest landslide ratio, followed by bamboo, betel nut, and tea. Landslides thus show a higher ratio in areas planted with shallow root vegetation such as bamboo, betel nut, and tea. Furthermore, the degree of basin development is proportional to the landslide ratio. The results show that a change in vegetation cover results in a modified landslide area and frequency and changed land use areas have higher landslide ratios than non-changed. Land use management and community-based disaster prevention are needed in mountainous areas of Taiwan for hazard mitigation. PMID:22961329

Chen, Chien-Yuan; Huang, Wen-Lin

2013-05-01