The deep space network

NASA Technical Reports Server (NTRS)

1974-01-01

The progress is reported of Deep Space Network (DSN) research in the following areas: (1) flight project support, (2) spacecraft/ground communications, (3) station control and operations technology, (4) network control and processing, and (5) deep space stations. A description of the DSN functions and facilities is included.

The deep space network, volume 16

NASA Technical Reports Server (NTRS)

1973-01-01

The objectives, functions, and organization of the DSN are summarized, and the instrumentation facility, ground communication facility, and the network control system are described. The requirements for supporting planetary flight projects are discussed along with the research and technology for tracking, navigation, network control, and data processing.

Comparative analyses of different variants of standard ground for automatic control systems of technical processes of oil and gas production

NASA Astrophysics Data System (ADS)

Gromakov, E. I.; Gazizov, A. T.; Lukin, V. P.; Chimrov, A. V.

2017-01-01

The paper analyses efficiency (interference resistance) of standard TT, TN, IT networks in control links of automatic control systems (ACS) of technical processes (TP) of oil and gas production. Electromagnetic compatibility (EMC) is a standard term used to describe the interference in grounding circuits. Improved EMC of ACS TP can significantly reduce risks and costs of malfunction of equipment that could have serious consequences. It has been proved that an IT network is the best type of grounds for protection of ACS TP in real life conditions. It allows reducing the interference down to the level that is stated in standards of oil and gas companies.

The Deep Space Network. [tracking and communication functions and facilities

NASA Technical Reports Server (NTRS)

1974-01-01

The objectives, functions, and organization of the Deep Space Network are summarized. The Deep Space Instrumentation Facility, the Ground Communications Facility, and the Network Control System are described.

The deep space network

NASA Technical Reports Server (NTRS)

1977-01-01

The facilities, programming system, and monitor and control system for the deep space network are described. Ongoing planetary and interplanetary flight projects are reviewed, along with tracking and ground-based navigation, communications, and network and facility engineering.

Water-resources data network evaluation for Monterey County, California; Phase 2, northern and coastal areas of Monterey County

USGS Publications Warehouse

Templin, W.E.; Smith, P.E.; DeBortoli, M.L.; Schluter, R.C.

1995-01-01

This report presents an evaluation of water- resources data-collection networks in the northern and coastal areas of Monterey County, California. This evaluation was done by the U.S. Geological Survey in cooperation with the Monterey County Flood Control and Water Conservation District to evaluate precipitation, surface water, and ground water monitoring networks. This report describes existing monitoring networks in the study areas and areas where possible additional data-collection is needed. During this study, 106 precipitation-quantity gages were identified, of which 84 were active; however, no precipitation-quality gages were identified in the study areas. The precipitaion-quantity gages were concentrated in the Monterey Peninsula and the northern part of the county. If the number of gages in these areas were reduced, coverage would still be adequate to meet most objectives; however, additional gages could improve coverage in the Tularcitos Creek basin and in the coastal areas south of Carmel to the county boundary. If collection of precipitation data were expanded to include monitoring precipitation quality, this expanded monitoring also could include monitoring precipitation for acid rain and pesticides. Eleven continuous streamflow-gaging stations were identified during this study, of which seven were active. To meet the objectives of the streamflow networks outlined in this report, the seven active stations would need to be continued, four stations would need to be reactivated, and an additional six streamflow-gaging stations would need to be added. Eleven stations that routinely were sampled for chemical constituents were identified in the study areas. Surface water in the lower Big Sur River basin was sampled annually for total coli- form and fecal coliform bacteria, and the Big Sur River was sampled monthly at 16 stations for these bacteria. Routine sampling for chemical constituents also was done in the Big Sur River basin. The Monterey County Flood Control and Water Conservation District maintained three networks in the study areas to measure ground-water levels: (1) the summer network, (2) the monthly network, and (3) the annual autumn network. The California American Water Company also did some ground-water-level monitoring in these areas. Well coverage for ground-water monitoring was dense in the seawater-intrusion area north of Moss Landing (possibly because of multiple overlying aquifers), but sparse in other parts of the study areas. During the study, 44 sections were identified as not monitored for ground-water levels. In an ideal ground-water-level network, wells would be evenly spaced, except where local conditions or correlations of wells make monitoring unnecessary. A total of 384 wells that monitor ground-water levels and/or ground-water quality were identified during this study. The Monterey County Flood Control and Water Conservation District sampled ground-water quality monthly during the irrigation season to monitor seawater intrusion. Once each year (during the summer), the wells in this network were monitored for chlorides, specific conductance, and nitrates. Additional samples were collected from each well once every 5 years for complete mineral analysis. The California Department of Health Services, the California American Water Company, the U.S. Army Health Service at Ford Ord, and the Monterey Peninsula Water Management District also monitored ground-water quality in wells in the study areas. Well coverage for the ground-water- quality networks was dense in the seawater- intrusion area north of Moss Landing, but sparse in the rest of the study areas. During this study, 54 sections were identified as not monitored for water quality.

International Symposium on Spacecraft Ground Control and Flight Dynamics, SCD1, Sao Jose dos Campos, Brazil, Feb. 7-11, 1994

NASA Astrophysics Data System (ADS)

Rozenfeld, Pawel; Kuga, Helio Koiti; Orlando, Valcir

An international symposium on spacecraft flight dynamics and ground control systems produced 85 papers in the areas of attitude determination and control, orbit control, satellite constellation strategies, stationkeeping, spacecraft maneuvering, orbit determination, astrodynamics, ground command and control systems, and mission operations. Several papers included discussions on the application of artificial intelligence, neural networks, expert systems, and ion propulsion. For individual titles, see A95-89098 through A95-89182.

The Telecommunications and Data Acquisition Report

NASA Technical Reports Server (NTRS)

Posner, E. C. (Editor)

1984-01-01

Activities in space communication, radio navigation, radio science, and ground-based astronomy are reported. Advanced systems for the Deep Space Network and its Ground-Communications Facility are discussed including station control and system technology. Network sustaining as well as data and information systems are covered. Studies of geodynamics, investigations of the microwave spectrum, and the search for extraterrestrial intelligence are reported.

The Deep Space Network information system in the year 2000

NASA Technical Reports Server (NTRS)

Markley, R. W.; Beswick, C. A.

1992-01-01

The Deep Space Network (DSN), the largest, most sensitive scientific communications and radio navigation network in the world, is considered. Focus is made on the telemetry processing, monitor and control, and ground data transport architectures of the DSN ground information system envisioned for the year 2000. The telemetry architecture will be unified from the front-end area to the end user. It will provide highly automated monitor and control of the DSN, automated configuration of support activities, and a vastly improved human interface. Automated decision support systems will be in place for DSN resource management, performance analysis, fault diagnosis, and contingency management.

Design and Performance of the Acts Gigabit Satellite Network High Data-Rate Ground Station

NASA Technical Reports Server (NTRS)

Hoder, Doug; Kearney, Brian

1995-01-01

The ACTS High Data-Rate Ground stations were built to support the ACTS Gigabit Satellite Network (GSN). The ACTS GSN was designed to provide fiber-compatible SONET service to remote nodes and networks through a wideband satellite system. The ACTS satellite is unique in its extremely wide bandwidth, and electronically controlled spot beam antennas. This paper discusses the requirements, design and performance of the RF section of the ACTS High Data-Rate Ground Stations and constituent hardware. The ACTS transponder systems incorporate highly nonlinear hard limiting. This introduced a major complexity in to the design and subsequent modification of the ground stations. A discussion of the peculiarities of the A CTS spacecraft transponder system and their impact is included.

Tracking and data relay satellite system: NASA's new spacecraft data acquisition system

NASA Astrophysics Data System (ADS)

Schneider, W. C.; Garman, A. A.

The growth in NASA's ground network complexity and cost triggered a search for an alternative. Through a lease service contract, Western Union will provide to NASA 10 years of space communications services with a Tracking and Data Relay Satellite System (TDRSS). A constellation of four operating satellites in geostationary orbit and a single ground terminal will provide complete tracking, telemetry and command service for all of NASA's Earth orbital satellites below an altitude of 12,000 km. The system is shared: two satellites will be dedicated to NASA service; a third will provide backup as a shared spare; the fourth satellite will be dedicated to Western Union's Advanced Westar commercial service. Western Union will operate the ground terminal and provide operational satellite control. NASA's Network Control Center will provide the focal point for scheduling user services and controlling the interface between TDRSS and the rest of the NASA communications network, project control centers and data processing facilities. TDRSS single access user spacecraft data systems should be designed for efficient time shared data relay support. Reimbursement policy and rate structure for non-NASA users are currently being developed.

On-board congestion control for satellite packet switching networks

NASA Technical Reports Server (NTRS)

Chu, Pong P.

1991-01-01

It is desirable to incorporate packet switching capability on-board for future communication satellites. Because of the statistical nature of packet communication, incoming traffic fluctuates and may cause congestion. Thus, it is necessary to incorporate a congestion control mechanism as part of the on-board processing to smooth and regulate the bursty traffic. Although there are extensive studies on congestion control for both baseband and broadband terrestrial networks, these schemes are not feasible for space based switching networks because of the unique characteristics of satellite link. Here, we propose a new congestion control method for on-board satellite packet switching. This scheme takes into consideration the long propagation delay in satellite link and takes advantage of the the satellite's broadcasting capability. It divides the control between the ground terminals and satellite, but distributes the primary responsibility to ground terminals and only requires minimal hardware resource on-board satellite.

The Telecommunications and Data Acquisition Report

NASA Technical Reports Server (NTRS)

Posner, E. C. (Editor)

1987-01-01

Topics addressed include: tracking and ground-based navigation; communications, spacecraft-ground; station control and system technology; capabilities for existing projects; network upgrade and sustaining; mission interface and support; and Ka-band capabilities.

A Framework for Dimensioning VDL-2 Air-Ground Networks

NASA Technical Reports Server (NTRS)

Ribeiro, Leila Z.; Monticone, Leone C.; Snow, Richard E.; Box, Frank; Apaza, Rafel; Bretmersky, Steven

2014-01-01

This paper describes a framework developed at MITRE for dimensioning a Very High Frequency (VHF) Digital Link Mode 2 (VDL-2) Air-to-Ground network. This framework was developed to support the FAA's Data Communications (Data Comm) program by providing estimates of expected capacity required for the air-ground network services that will support Controller-Pilot-Data-Link Communications (CPDLC), as well as the spectrum needed to operate the system at required levels of performance. The Data Comm program is part of the FAA's NextGen initiative to implement advanced communication capabilities in the National Airspace System (NAS). The first component of the framework is the radio-frequency (RF) coverage design for the network ground stations. Then we proceed to describe the approach used to assess the aircraft geographical distribution and the data traffic demand expected in the network. The next step is the resource allocation utilizing optimization algorithms developed in MITRE's Spectrum ProspectorTM tool to propose frequency assignment solutions, and a NASA-developed VDL-2 tool to perform simulations and determine whether a proposed plan meets the desired performance requirements. The framework presented is capable of providing quantitative estimates of multiple variables related to the air-ground network, in order to satisfy established coverage, capacity and latency performance requirements. Outputs include: coverage provided at different altitudes; data capacity required in the network, aggregated or on a per ground station basis; spectrum (pool of frequencies) needed for the system to meet a target performance; optimized frequency plan for a given scenario; expected performance given spectrum available; and, estimates of throughput distributions for a given scenario. We conclude with a discussion aimed at providing insight into the tradeoffs and challenges identified with respect to radio resource management for VDL-2 air-ground networks.

U.S. Geological Survey Ground-Water Climate Response Network

USGS Publications Warehouse

,

2007-01-01

The U.S. Geological Survey serves the Nation by providing reliable hydrologic information used by others to manage the Nation's water resources. The U.S. Geological Survey (USGS) measures more than 20,000 wells each year for a variety of objectives as part of Federal programs and in cooperation with State and local agencies. Water-level data are collected using consistent data-collection and quality-control methods. A small subset of these wells meets the criteria necessary to be included in a 'Climate Response Network' of wells designed to illustrate the response of the ground-water system to climate variations nationwide. The primary purpose of the Climate Response Network is to portray the effect of climate on ground-water levels in unconfined aquifers or near-surface confined aquifers that are minimally affected by pumping or other anthropogenic stresses. The Climate Response Network Web site (http://groundwaterwatch.usgs.gov/) is the official USGS Web site for illustrating current ground-water conditions in the United States and Puerto Rico. The Climate Response Network Web pages provide information on ground-water conditions at a variety of scales. A national map provides a broad overview of water-table conditions across the Nation. State maps provide a more local picture of ground-water conditions. Site pages provide the details about a specific well.

Network command processing system overview

NASA Technical Reports Server (NTRS)

Nam, Yon-Woo; Murphy, Lisa D.

1993-01-01

The Network Command Processing System (NCPS) developed for the National Aeronautics and Space Administration (NASA) Ground Network (GN) stations is a spacecraft command system utilizing a MULTIBUS I/68030 microprocessor. This system was developed and implemented at ground stations worldwide to provide a Project Operations Control Center (POCC) with command capability for support of spacecraft operations such as the LANDSAT, Shuttle, Tracking and Data Relay Satellite, and Nimbus-7. The NCPS consolidates multiple modulation schemes for supporting various manned/unmanned orbital platforms. The NCPS interacts with the POCC and a local operator to process configuration requests, generate modulated uplink sequences, and inform users of the ground command link status. This paper presents the system functional description, hardware description, and the software design.

The deep space network, volume 15

NASA Technical Reports Server (NTRS)

1973-01-01

The DSN progress is reported in flight project support, TDA research and technology, network engineering, hardware and software implementation, and operations. Topics discussed include: DSN functions and facilities, planetary flight projects, tracking and ground-based navigation, communications, data processing, network control system, and deep space stations.

Constellation Program Electrical Ground Support Equipment Research and Development

NASA Technical Reports Server (NTRS)

McCoy, Keegan S.

2010-01-01

At the Kennedy Space Center, I engaged in the research and development of electrical ground support equipment for NASA's Constellation Program. Timing characteristics playa crucial role in ground support communications. Latency and jitter are two problems that must be understood so that communications are timely and consistent within the Kennedy Ground Control System (KGCS). I conducted latency and jitter tests using Alien-Bradley programmable logic controllers (PLCs) so that these two intrinsic network properties can be reduced. Time stamping and clock synchronization also play significant roles in launch processing and operations. Using RSLogix 5000 project files and Wireshark network protocol analyzing software, I verified master/slave PLC Ethernet module clock synchronization, master/slave IEEE 1588 communications, and time stamping capabilities. All of the timing and synchronization test results are useful in assessing the current KGCS operational level and determining improvements for the future.

Quantifying the spatio-temporal pattern of the ground impact of space weather events using dynamical networks formed from the SuperMAG database of ground based magnetometer stations.

NASA Astrophysics Data System (ADS)

Dods, Joe; Chapman, Sandra; Gjerloev, Jesper

2016-04-01

Quantitative understanding of the full spatial-temporal pattern of space weather is important in order to estimate the ground impact. Geomagnetic indices such as AE track the peak of a geomagnetic storm or substorm, but cannot capture the full spatial-temporal pattern. Observations by the ~100 ground based magnetometers in the northern hemisphere have the potential to capture the detailed evolution of a given space weather event. We present the first analysis of the full available set of ground based magnetometer observations of substorms using dynamical networks. SuperMAG offers a database containing ground station magnetometer data at a cadence of 1min from 100s stations situated across the globe. We use this data to form dynamic networks which capture spatial dynamics on timescales from the fast reconfiguration seen in the aurora, to that of the substorm cycle. Windowed linear cross-correlation between pairs of magnetometer time series along with a threshold is used to determine which stations are correlated and hence connected in the network. Variations in ground conductivity and differences in the response functions of magnetometers at individual stations are overcome by normalizing to long term averages of the cross-correlation. These results are tested against surrogate data in which phases have been randomised. The network is then a collection of connected points (ground stations); the structure of the network and its variation as a function of time quantify the detailed dynamical processes of the substorm. The network properties can be captured quantitatively in time dependent dimensionless network parameters and we will discuss their behaviour for examples of 'typical' substorms and storms. The network parameters provide a detailed benchmark to compare data with models of substorm dynamics, and can provide new insights on the similarities and differences between substorms and how they correlate with external driving and the internal state of the magnetosphere. We can also investigate the solar wind control of the magnetospheric-ionospheric convection system using dynamical networks. The dynamical networks are first interpolated onto a regular grid. Statistically averaged network responses are then formed for a variety of solar wind conditions, including investigating the network response to southward turnings. [1] Dods, J., S. C. Chapman, and J. W. Gjerloev (2015), Network analysis of geomagnetic substorms using the SuperMAG database of ground-based magnetometer stations, J. Geophys. Res. Space Physics, 120, 7774-7784, doi:10.1002/2015JA021456

Tracking and data relay satellite system - NASA's new spacecraft data acquisition system

NASA Technical Reports Server (NTRS)

Schneider, W. C.; Garman, A. A.

1979-01-01

This paper describes NASA's new spacecraft acquisition system provided by the Tracking and Data Relay Satellite System (TDRSS). Four satellites in geostationary orbit and a ground terminal will provide complete tracking, telemetry, and command service for all of NASA's orbital satellites below a 12,000 km altitude. Western Union will lease the system, operate the ground terminal and provide operational satellite control. NASA's network control center will be the focal point for scheduling user services and controlling the interface between TDRSS and the NASA communications network, project control centers, and data processing. TDRSS single access user spacecraft data systems will be designed for time shared data relay support, and reimbursement policy and rate structure for non-NASA users are being developed.

The Telecommunications and Data Acquisition Report

NASA Technical Reports Server (NTRS)

Posner, E. C. (Editor)

1992-01-01

Archival reports on developments in programs managed by JPL's Office of Telecommunications and Data Acquisition (TDA) are provided. In space communications, radio navigation, radio science, and ground-based radio and radar astronomy, it reports on activities of the Deep Space Network (DSN) in planning, in supporting research and technology, in implementation, and in operations. Also included is standards activity at JPL for space data and information. In the search for extraterrestrial intelligence (SETI), the TDA Progress Report reports on implementation and operations for searching the microwave spectrum. Topics covered include tracking and ground-based navigation; communications, spacecraft-ground; station control and system technology; capabilities for new projects; network upgrade and sustaining; network operations and operations support; and TDA program management and analysis.

The deep space network, volume 12

NASA Technical Reports Server (NTRS)

1972-01-01

Progress in the development of the DSN is reported along with TDA research and technology, network engineering, hardware, and software implementation. Included are descriptions of the DSN function and facilities, Helios mission support, Mariner Venus/Mercury 1973 mission support, Viking mission support, tracking and ground-based navigation, communications, network control and data processing, and deep space stations.

Rapid Network Design

DTIC Science & Technology

2013-09-01

control GCE ground combat element LCE logistics combat element MAGTF Marine Air Ground Task Force MWCS Marine Wing Communications Squadron NPS Naval...elements: command element (CE), ground combat el- ement ( GCE ), aviation combat element (ACE), and logistics combat element (LCE). Each ele- ment...This layer provides unimpeded high-speed connectivity between remote sites and the Internet. Limited security policies are applied at this level to

A network control concept for the 30/20 GHz communication system baseband processor

NASA Technical Reports Server (NTRS)

Sabourin, D. J.; Hay, R. E.

1982-01-01

The architecture and system design for a satellite-switched TDMA communication system employing on-board processing was developed by Motorola for NASA's Lewis Research Center. The system design is based on distributed processing techniques that provide extreme flexibility in the selection of a network control protocol without impacting the satellite or ground terminal hardware. A network control concept that includes system synchronization and allows burst synchronization to occur within the system operational requirement is described. This concept integrates the tracking and control links with the communication links via the baseband processor, resulting in an autonomous system operational approach.

Achieving QoS for Aeronautical Telecommunication Networks Over Differentiated Services

NASA Technical Reports Server (NTRS)

Bai, Haowei; Atiquzzaman, Mohammed; Ivanic, William

2001-01-01

Aeronautical Telecommunication Network (ATN) has been developed by the International Civil Aviation Organization to integrate Air-Ground and Ground-Ground data communication for aeronautical applications into a single network serving Air Traffic Control and Aeronautical Operational Communications. To carry time critical information required for aeronautical applications, ATN provides different Quality of Services (QoS) to applications. ATN has therefore, been designed as a stand alone network which implies building an expensive separate network for ATN However, the cost of operating ATN can be reduced if it can be run over a public network such as the Internet. Although the current Internet does not provide QoS the next generation Internet is expected to provide QoS to applications. The objective of this paper is to investigate the possibility of providing QoS to ATN applications when it is run over the next generation Internet. Differentiated Services (DiffServ), one of the protocols proposed for the next generation Internet, will allow network service providers to offer different QoS to customers. Our results show that it is possible to provide QoS to ATN applications when they run over a DiffServ backbone.

Achieving QoS for Aeronautical Telecommunication Networks over Differentiated Services

NASA Technical Reports Server (NTRS)

Bai, Haowei; Atiquzzaman, Mohammed; Ivancic, William

2001-01-01

Aeronautical Telecommunication Network (ATN) has been developed by the International Civil Aviation Organization to integrate Air-Ground and Ground-Ground data communication for aeronautical applications into a single network serving Air Traffic Control and Aeronautical Operational Communications. To carry time critical information required for aeronautical applications, ATN provides different Quality of Services (QoS) to applications. ATN has therefore, been designed as a standalone network which implies building an expensive separate network for ATN. However, the cost of operating ATN can be reduced if it can be run over a public network such as the Internet. Although the current Internet does not provide QoS, the next generation Internet is expected to provide QoS to applications. The objective of this paper is to investigate the possibility of providing QoS to ATN applications when it is run over the next generation Internet. Differentiated Services (DiffServ), one of the protocols proposed for the next generation Internet, will allow network service providers to offer different QoS to customers. Our results show that it is possible to provide QoS to ATN applications when they run over a DiffServ backbone.

The National Aeronautics and Space Administration (NASA) Tracking and Data Relay Satellite System (TDRSS) program Economic and programmatic, considerations

NASA Technical Reports Server (NTRS)

Aller, R. O.

1985-01-01

The Tracking and Data Relay Satellite System (TDRSS) represents the principal element of a new space-based tracking and communication network which will support NASA spaceflight missions in low earth orbit. In its complete configuration, the TDRSS network will include a space segment consisting of three highly specialized communication satellites in geosynchronous orbit, a ground segment consisting of an earth terminal, and associated data handling and control facilities. The TDRSS network has the objective to provide communication and data relay services between the earth-orbiting spacecraft and their ground-based mission control and data handling centers. The first TDRSS spacecraft has been now in service for two years. The present paper is concerned with the TDRSS experience from the perspective of the various programmatic and economic considerations which relate to the program.

Networks Technology Conference

NASA Technical Reports Server (NTRS)

Tasaki, Keiji K. (Editor)

1993-01-01

The papers included in these proceedings represent the most interesting and current topics being pursued by personnel at GSFC's Networks Division and supporting contractors involved in Space, Ground, and Deep Space Network (DSN) technical work. Although 29 papers are represented in the proceedings, only 12 were presented at the conference because of space and time limitations. The proceedings are organized according to five principal technical areas of interest to the Networks Division: Project Management; Network Operations; Network Control, Scheduling, and Monitoring; Modeling and Simulation; and Telecommunications Engineering.

DoD Comprehensive Military Unmanned Aerial Vehicle Smart Device Ground Control Station Threat Model

DTIC Science & Technology

2015-04-01

design , imple- mentation, and test evaluation were interviewed to evaluate the existing gaps in the DoD processes for cybersecurity. This group exposed...such as antenna design and signal reception have made satellite communication networks a viable solution for smart devices on the battlefield...DoD Comprehensive Military Unmanned AERIAL VEHICLE SMART DEVICE GROUND CONTROL STATION THREAT MODEL  Image designed by Diane Fleischer Report

Shuttle Payload Ground Command and Control: An Experiment Implementation Combustion Module-2 Software Development, STS-107

NASA Technical Reports Server (NTRS)

Carek, David Andrew

2003-01-01

This presentation covers the design of a command and control architecture developed by the author for the Combustion Module-2 microgravity experiment, which flew aboard the STS-107 Shuttle mission, The design was implemented to satisfy a hybrid network that utilized TCP/IP for both the onboard segment and ground segment, with an intermediary unreliable transport for the space to ground segment. With the infusion of Internet networking technologies into Space Shuttle, Space Station, and spacecraft avionics systems, comes the need for robust methodologies for ground command and control. Considerations of high bit error links, and unreliable transport over intermittent links must be considered in such systems. Internet protocols applied to these systems, coupled with the appropriate application layer protections, can provide adequate communication architectures for command and control. However, there are inherent limitations and additional complexities added by the use of Internet protocols that must be considered during the design. This presentation will discuss the rationale for the: framework and protocol algorithms developed by the author. A summary of design considerations, implantation issues, and learned lessons will be will be presented. A summary of mission results using this communications architecture will be presented. Additionally, areas of further needed investigation will be identified.

The deep space network

NASA Technical Reports Server (NTRS)

1975-01-01

The objectives, functions, and organization of the Deep Space Network are summarized along with deep space station, ground communication, and network operations control capabilities. Mission support of ongoing planetary/interplanetary flight projects is discussed with emphasis on Viking orbiter radio frequency compatibility tests, the Pioneer Venus orbiter mission, and Helios-1 mission status and operations. Progress is also reported in tracking and data acquisition research and technology, network engineering, hardware and software implementation, and operations.

The Deep Space Network

NASA Technical Reports Server (NTRS)

1974-01-01

The objectives, functions, and organization, of the Deep Space Network are summarized. Deep Space stations, ground communications, and network operations control capabilities are described. The network is designed for two-way communications with unmanned spacecraft traveling approximately 1600 km from earth to the farthest planets in the solar system. It has provided tracking and data acquisition support for the following projects: Ranger, Surveyor, Mariner, Pioneer, Apollo, Helios, Viking, and the Lunar Orbiter.

Expanding the NATO Movement Control Network

DTIC Science & Technology

2016-05-17

nations and abide by their governing rules for highway, air, rail, and vessel movements . The “Strong Europe” movement network extends operational access...national movement coordi- nation centers (NMCCs). The in- teroperability and relationships that are developed there enhance the early entry of forces...by air, ground, sea, and rail. In January 2015, Operation At- lantic Resolve provided the 624th Movement Control Team (MCT), which was forward

TDRSS operations control analysis study

NASA Technical Reports Server (NTRS)

1976-01-01

The use of an operational Tracking and Data Relay Satellite System (TDRSS) and the remaining ground stations for the STDN (GSTDN) was investigated. The operational aspects of TDRSS concepts, GSTDN as a 14-site network, and GSTDN as a 7 site-network were compared and operations control concepts for the configurations developed. Man/machine interface, scheduling system, and hardware/software tradeoff analyses were among the factors considered in the analysis.

Launch Processing System. [for Space Shuttle

NASA Technical Reports Server (NTRS)

Byrne, F.; Doolittle, G. V.; Hockenberger, R. W.

1976-01-01

This paper presents a functional description of the Launch Processing System, which provides automatic ground checkout and control of the Space Shuttle launch site and airborne systems, with emphasis placed on the Checkout, Control, and Monitor Subsystem. Hardware and software modular design concepts for the distributed computer system are reviewed relative to performing system tests, launch operations control, and status monitoring during ground operations. The communication network design, which uses a Common Data Buffer interface to all computers to allow computer-to-computer communication, is discussed in detail.

PV-Diesel Hybrid SCADA Experiment Network Design

NASA Technical Reports Server (NTRS)

Kalu, Alex; Durand, S.; Emrich, Carol; Ventre, G.; Wilson, W.; Acosta, R.

1999-01-01

The essential features of an experimental network for renewable power system satellite based supervisory, control and data acquisition (SCADA) are communication links, controllers, diagnostic equipment and a hybrid power system. Required components for implementing the network consist of two satellite ground stations, to satellite modems, two 486 PCs, two telephone receivers, two telephone modems, two analog telephone lines, one digital telephone line, a hybrid-power system equipped with controller and a satellite spacecraft. In the technology verification experiment (TVE) conducted by Savannah State University and Florida Solar Energy Center, the renewable energy hybrid system is the Apex-1000 Mini-Hybrid which is equipped with NGC3188 for user interface and remote control and the NGC2010 for monitoring and basic control tasks. This power system is connected to a satellite modem via a smart interface, RS232. Commands are sent to the power system control unit through a control PC designed as PC1. PC1 is thus connected to a satellite model through RS232. A second PC, designated PC2, the diagnostic PC is connected to both satellite modems via separate analog telephone lines for checking modems'health. PC2 is also connected to PC1 via a telephone line. Due to the unavailability of a second ground station for the ACTS, one ground station is used to serve both the sending and receiving functions in this experiment. Signal is sent from the control PC to the Hybrid system at a frequency f(sub 1), different from f(sub 2), the signal from the hybrid system to the control PC. f(sub l) and f(sub 2) are sufficiently separated to avoid interference.

Role of Graph Architecture in Controlling Dynamical Networks with Applications to Neural Systems.

PubMed

Kim, Jason Z; Soffer, Jonathan M; Kahn, Ari E; Vettel, Jean M; Pasqualetti, Fabio; Bassett, Danielle S

2018-01-01

Networked systems display complex patterns of interactions between components. In physical networks, these interactions often occur along structural connections that link components in a hard-wired connection topology, supporting a variety of system-wide dynamical behaviors such as synchronization. While descriptions of these behaviors are important, they are only a first step towards understanding and harnessing the relationship between network topology and system behavior. Here, we use linear network control theory to derive accurate closed-form expressions that relate the connectivity of a subset of structural connections (those linking driver nodes to non-driver nodes) to the minimum energy required to control networked systems. To illustrate the utility of the mathematics, we apply this approach to high-resolution connectomes recently reconstructed from Drosophila, mouse, and human brains. We use these principles to suggest an advantage of the human brain in supporting diverse network dynamics with small energetic costs while remaining robust to perturbations, and to perform clinically accessible targeted manipulation of the brain's control performance by removing single edges in the network. Generally, our results ground the expectation of a control system's behavior in its network architecture, and directly inspire new directions in network analysis and design via distributed control.

Role of graph architecture in controlling dynamical networks with applications to neural systems

NASA Astrophysics Data System (ADS)

Kim, Jason Z.; Soffer, Jonathan M.; Kahn, Ari E.; Vettel, Jean M.; Pasqualetti, Fabio; Bassett, Danielle S.

2018-01-01

Networked systems display complex patterns of interactions between components. In physical networks, these interactions often occur along structural connections that link components in a hard-wired connection topology, supporting a variety of system-wide dynamical behaviours such as synchronization. Although descriptions of these behaviours are important, they are only a first step towards understanding and harnessing the relationship between network topology and system behaviour. Here, we use linear network control theory to derive accurate closed-form expressions that relate the connectivity of a subset of structural connections (those linking driver nodes to non-driver nodes) to the minimum energy required to control networked systems. To illustrate the utility of the mathematics, we apply this approach to high-resolution connectomes recently reconstructed from Drosophila, mouse, and human brains. We use these principles to suggest an advantage of the human brain in supporting diverse network dynamics with small energetic costs while remaining robust to perturbations, and to perform clinically accessible targeted manipulation of the brain's control performance by removing single edges in the network. Generally, our results ground the expectation of a control system's behaviour in its network architecture, and directly inspire new directions in network analysis and design via distributed control.

A global spacecraft control network for spacecraft autonomy research

NASA Technical Reports Server (NTRS)

Kitts, Christopher A.

1996-01-01

The development and implementation of the Automated Space System Experimental Testbed (ASSET) space operations and control network, is reported on. This network will serve as a command and control architecture for spacecraft operations and will offer a real testbed for the application and validation of advanced autonomous spacecraft operations strategies. The proposed network will initially consist of globally distributed amateur radio ground stations at locations throughout North America and Europe. These stations will be linked via Internet to various control centers. The Stanford (CA) control center will be capable of human and computer based decision making for the coordination of user experiments, resource scheduling and fault management. The project's system architecture is described together with its proposed use as a command and control system, its value as a testbed for spacecraft autonomy research, and its current implementation.

Training augmentation device for the Air Force satellite Control Network

NASA Technical Reports Server (NTRS)

Shoates, Keith B.

1993-01-01

From the 1960's and into the early 1980's satellite operations and control were conducted by Air Force Systems Command (AFSC), now Air Force Materiel Command (AFMC), out of the Satellite Control Facility at Onizuka AFB, CA. AFSC was responsible for acquiring satellite command and control systems and conducting routine satellite operations. The daily operations, consisting of satellite health and status contacts and station keeping activities, were performed for AFSC by a Mission Control Team (MCT) staffed by civilian contractors who were responsible for providing their own technically 'qualified' personnel as satellite operators. An MCT consists of five positions: mission planner, ground controller, planner analyst, orbit analyst, and ranger controller. Most of the training consisted of On-the-Job-Training (OJT) with junior personnel apprenticed to senior personnel until they could demonstrate job proficiency. With most of the satellite operators having 15 to 25 years of experience, there was minimal risk to the mission. In the mid 1980's Air Force Space Command (AFSPACOM) assumed operational responsibility for a newly established control node at Falcon AFB (FAFB) in CO. The satellites and ground system program offices (SPO's) are organized under AFSC's Space and Missiles Systems Center (SMC) to function as a systems engineering and acquisition agency for AFSPACECOM. The collection of the satellite control nodes, ground tracking stations, computer processing equipment, and connecting communications links is referred to as the Air Force Satellite Control Network (AFSCN).

RBF neural network based PI pitch controller for a class of 5-MW wind turbines using particle swarm optimization algorithm.

PubMed

Poultangari, Iman; Shahnazi, Reza; Sheikhan, Mansour

2012-09-01

In order to control the pitch angle of blades in wind turbines, commonly the proportional and integral (PI) controller due to its simplicity and industrial usability is employed. The neural networks and evolutionary algorithms are tools that provide a suitable ground to determine the optimal PI gains. In this paper, a radial basis function (RBF) neural network based PI controller is proposed for collective pitch control (CPC) of a 5-MW wind turbine. In order to provide an optimal dataset to train the RBF neural network, particle swarm optimization (PSO) evolutionary algorithm is used. The proposed method does not need the complexities, nonlinearities and uncertainties of the system under control. The simulation results show that the proposed controller has satisfactory performance. Copyright © 2012 ISA. Published by Elsevier Ltd. All rights reserved.

Heterogeneous Spacecraft Networks

NASA Technical Reports Server (NTRS)

Nakamura, Yosuke (Inventor); Faber, Nicolas T. (Inventor); Frost, Chad R. (Inventor); Alena, Richard L. (Inventor)

2018-01-01

The present invention provides a heterogeneous spacecraft network including a network management architecture to facilitate communication between a plurality of operations centers and a plurality of data user communities. The network management architecture includes a plurality of network nodes in communication with the plurality of operations centers. The present invention also provides a method of communication for a heterogeneous spacecraft network. The method includes: transmitting data from a first space segment to a first ground segment; transmitting the data from the first ground segment to a network management architecture; transmitting data from a second space segment to a second ground segment, the second space and ground segments having incompatible communication systems with the first space and ground segments; transmitting the data from the second ground station to the network management architecture; and, transmitting data from the network management architecture to a plurality of data user communities.

Ground vehicle control at NIST: From teleoperation to autonomy

NASA Technical Reports Server (NTRS)

Murphy, Karl N.; Juberts, Maris; Legowik, Steven A.; Nashman, Marilyn; Schneiderman, Henry; Scott, Harry A.; Szabo, Sandor

1994-01-01

NIST is applying their Real-time Control System (RCS) methodology for control of ground vehicles for both the U.S. Army Researh Lab, as part of the DOD's Unmanned Ground Vehicles program, and for the Department of Transportation's Intelligent Vehicle/Highway Systems (IVHS) program. The actuated vehicle, a military HMMWV, has motors for steering, brake, throttle, etc. and sensors for the dashboard gauges. For military operations, the vehicle has two modes of operation: a teleoperation mode--where an operator remotely controls the vehicle over an RF communications network; and a semi-autonomous mode called retro-traverse--where the control system uses an inertial navigation system to steer the vehicle along a prerecorded path. For the IVHS work, intelligent vision processing elements replace the human teleoperator to achieve autonomous, visually guided road following.

The Telecommunications and Data Acquisition Report

NASA Technical Reports Server (NTRS)

Posner, E. C. (Editor)

1991-01-01

This quarterly reports on space communications, radio navigation, radio science, and ground based radio and radar astronomy in connection with the Deep Space Network (DSN) in planning, supporting research and technology, implementation, and in operations. Also included is standards activity at JPL for space data and information systems and DSN work. Specific areas of research are: Tracking and ground based navigation; Spacecraft and ground communications; Station control and system technology; DSN Systems Implementation; and DSN Operations.

A conceptual ground-water-quality monitoring network for San Fernando Valley, California

USGS Publications Warehouse

Setmire, J.G.

1985-01-01

A conceptual groundwater-quality monitoring network was developed for San Fernando Valley to provide the California State Water Resources Control Board with an integrated, basinwide control system to monitor the quality of groundwater. The geology, occurrence and movement of groundwater, land use, background water quality, and potential sources of pollution were described and then considered in designing the conceptual monitoring network. The network was designed to monitor major known and potential point and nonpoint sources of groundwater contamination over time. The network is composed of 291 sites where wells are needed to define the groundwater quality. The ideal network includes four specific-purpose networks to monitor (1) ambient water quality, (2) nonpoint sources of pollution, (3) point sources of pollution, and (4) line sources of pollution. (USGS)

Ground Control Point - Wireless System Network for UAV-based environmental monitoring applications

NASA Astrophysics Data System (ADS)

Mejia-Aguilar, Abraham

2016-04-01

In recent years, Unmanned Aerial Vehicles (UAV) have seen widespread civil applications including usage for survey and monitoring services in areas such as agriculture, construction and civil engineering, private surveillance and reconnaissance services and cultural heritage management. Most aerial monitoring services require the integration of information acquired during the flight (such as imagery) with ground-based information (such as GPS information or others) for improved ground truth validation. For example, to obtain an accurate 3D and Digital Elevation Model based on aerial imagery, it is necessary to include ground-based information of coordinate points, which are normally acquired with surveying methods based on Global Position Systems (GPS). However, GPS surveys are very time consuming and especially for longer time series of monitoring data repeated GPS surveys are necessary. In order to improve speed of data collection and integration, this work presents an autonomous system based on Waspmote technologies build on single nodes interlinked in a Wireless Sensor Network (WSN) star-topology for ground based information collection and later integration with surveying data obtained by UAV. Nodes are designed to be visible from the air, to resist extreme weather conditions with low-power consumption. Besides, nodes are equipped with GPS as well as Inertial Measurement Unit (IMU), accelerometer, temperature and soil moisture sensors and thus provide significant advantages in a broad range of applications for environmental monitoring. For our purpose, the WSN transmits the environmental data with 3G/GPRS to a database on a regular time basis. This project provides a detailed case study and implementation of a Ground Control Point System Network for UAV-based vegetation monitoring of dry mountain grassland in the Matsch valley, Italy.

Discrete Event Command & Control for Networked Teams with Multiple Missions

DTIC Science & Technology

2009-03-16

Architecture for Unmanned Ground Systems ( JAUGS )10, and is an efficient means to realize the high-level OODA loops (observe, orient, decide, act) of 4D...for Unmanned Ground systems ( JAUGS )10, and is an efficient means to realize the OODA loops (observe, orient, decide, act) of 4D/RCS11. DEC is able to

Distributed Common Ground System-Navy Increment 2 (DCGS-N Inc 2)

DTIC Science & Technology

2016-03-01

15 minutes Enter and be Managed in the Network: Reference SvcV-7, Consolidated Afloat Networks and Enterprise Services ( CANES ) CDD, DCGS-N Inc 2...Red, White , Gray Data and Tracks to Command and Control System. Continuous Stream from SCI Common Intelligence Picture to General Service (GENSER...AIS - Automatic Information System AOC - Air Operations Command CANES - Consolidated Afloat Networks and Enterprise Services CID - Center for

Open source IPSEC software in manned and unmanned space missions

NASA Astrophysics Data System (ADS)

Edwards, Jacob

Network security is a major topic of research because cyber attackers pose a threat to national security. Securing ground-space communications for NASA missions is important because attackers could endanger mission success and human lives. This thesis describes how an open source IPsec software package was used to create a secure and reliable channel for ground-space communications. A cost efficient, reproducible hardware testbed was also created to simulate ground-space communications. The testbed enables simulation of low-bandwidth and high latency communications links to experiment how the open source IPsec software reacts to these network constraints. Test cases were built that allowed for validation of the testbed and the open source IPsec software. The test cases also simulate using an IPsec connection from mission control ground routers to points of interest in outer space. Tested open source IPsec software did not meet all the requirements. Software changes were suggested to meet requirements.

DSN test and training system

NASA Technical Reports Server (NTRS)

Thorman, H. C.

1975-01-01

Key characteristics of the Deep Space Network Test and Training System were presented. Completion of the Mark III-75 system implementation is reported. Plans are summarized for upgrading the system to a Mark III-77 configuration to support Deep Space Network preparations for the Mariner Jupiter/Saturn 1977 and Pioneer Venus 1978 missions. A general description of the Deep Space Station, Ground Communications Facility, and Network Operations Control Center functions that comprise the Deep Space Network Test and Training System is also presented.

Kennedy Space Center Timing and Countdown Interface to Kennedy Ground Control Subsystem

NASA Technical Reports Server (NTRS)

Olsen, James C.

2015-01-01

Kennedy Ground Control System (KGCS) engineers at the National Aeronautics and Space Administration (NASA) Kennedy Space Center (KSC) are developing a time-tagging process to enable reconstruction of the events during a launch countdown. Such a process can be useful in the case of anomalies or other situations where it is necessary to know the exact time an event occurred. It is thus critical for the timing information to be accurate. KGCS will synchronize all items with Coordinated Universal Time (UTC) obtained from the Timing and Countdown (T&CD) organization. Network Time Protocol (NTP) is the protocol currently in place for synchronizing UTC. However, NTP has a peak error that is too high for today's standards. Precision Time Protocol (PTP) is a newer protocol with a much smaller peak error. The focus of this project has been to implement a PTP solution on the network to increase timing accuracy while introducing and configuring the implementation of a firewall between T&CD and the KGCS network.

Tracking target objects orbiting earth using satellite-based telescopes

DOEpatents

De Vries, Willem H; Olivier, Scot S; Pertica, Alexander J

2014-10-14

A system for tracking objects that are in earth orbit via a constellation or network of satellites having imaging devices is provided. An object tracking system includes a ground controller and, for each satellite in the constellation, an onboard controller. The ground controller receives ephemeris information for a target object and directs that ephemeris information be transmitted to the satellites. Each onboard controller receives ephemeris information for a target object, collects images of the target object based on the expected location of the target object at an expected time, identifies actual locations of the target object from the collected images, and identifies a next expected location at a next expected time based on the identified actual locations of the target object. The onboard controller processes the collected image to identify the actual location of the target object and transmits the actual location information to the ground controller.

The College Football Student-Athlete's Academic Experience: Network Analysis and Model Development

ERIC Educational Resources Information Center

Young, Kyle McLendon

2010-01-01

A grounded theory research study employing network analysis as a means of facilitating the latter stages of the coding process was conducted at a selective university that competes at the highest level of college football. The purpose of the study was to develop a better understanding of how interactive dynamics and controlling mechanisms, such as…

Design and performance of an integrated ground and space sensor web for monitoring active volcanoes.

NASA Astrophysics Data System (ADS)

Lahusen, Richard; Song, Wenzhan; Kedar, Sharon; Shirazi, Behrooz; Chien, Steve; Doubleday, Joshua; Davies, Ashley; Webb, Frank; Dzurisin, Dan; Pallister, John

2010-05-01

An interdisciplinary team of computer, earth and space scientists collaborated to develop a sensor web system for rapid deployment at active volcanoes. The primary goals of this Optimized Autonomous Space In situ Sensorweb (OASIS) are to: 1) integrate complementary space and in situ (ground-based) elements into an interactive, autonomous sensor web; 2) advance sensor web power and communication resource management technology; and 3) enable scalability for seamless addition sensors and other satellites into the sensor web. This three-year project began with a rigorous multidisciplinary interchange that resulted in definition of system requirements to guide the design of the OASIS network and to achieve the stated project goals. Based on those guidelines, we have developed fully self-contained in situ nodes that integrate GPS, seismic, infrasonic and lightning (ash) detection sensors. The nodes in the wireless sensor network are linked to the ground control center through a mesh network that is highly optimized for remote geophysical monitoring. OASIS also features an autonomous bidirectional interaction between ground nodes and instruments on the EO-1 space platform through continuous analysis and messaging capabilities at the command and control center. Data from both the in situ sensors and satellite-borne hyperspectral imaging sensors stream into a common database for real-time visualization and analysis by earth scientists. We have successfully completed a field deployment of 15 nodes within the crater and on the flanks of Mount St. Helens, Washington. The demonstration that sensor web technology facilitates rapid network deployments and that we can achieve real-time continuous data acquisition. We are now optimizing component performance and improving user interaction for additional deployments at erupting volcanoes in 2010.

Deriving neural network controllers from neuro-biological data: implementation of a single-leg stick insect controller.

PubMed

von Twickel, Arndt; Büschges, Ansgar; Pasemann, Frank

2011-02-01

This article presents modular recurrent neural network controllers for single legs of a biomimetic six-legged robot equipped with standard DC motors. Following arguments of Ekeberg et al. (Arthropod Struct Dev 33:287-300, 2004), completely decentralized and sensori-driven neuro-controllers were derived from neuro-biological data of stick-insects. Parameters of the controllers were either hand-tuned or optimized by an evolutionary algorithm. Employing identical controller structures, qualitatively similar behaviors were achieved for robot and for stick insect simulations. For a wide range of perturbing conditions, as for instance changing ground height or up- and downhill walking, swing as well as stance control were shown to be robust. Behavioral adaptations, like varying locomotion speeds, could be achieved by changes in neural parameters as well as by a mechanical coupling to the environment. To a large extent the simulated walking behavior matched biological data. For example, this was the case for body support force profiles and swing trajectories under varying ground heights. The results suggest that the single-leg controllers are suitable as modules for hexapod controllers, and they might therefore bridge morphological- and behavioral-based approaches to stick insect locomotion control.

Apollo Soyuz test project press kit: USA-USSR

NASA Technical Reports Server (NTRS)

1975-01-01

The goals and program of the mission are described. Operations from preflight crew training through splashdown are included. Spacecraft and launch vehicle configurations are given. The 27 joint and unilateral experiments to be performed are described. A flight plan and a schedule of activities is included, together with brief crew biographies. The ground support system is discussed; it includes control centers in Houston and Moscow, and an ATS satellite to relay ground-air-ground communications. The global tracking network and the television transmission system are also described.

ACTS Ka-Band Earth Stations: Technology, Performance, and Lessons Learned

NASA Technical Reports Server (NTRS)

Reinhart, Richard C.; Struharik, Steven J.; Diamond, John J.; Stewart, David

2000-01-01

The Advanced Communications Technology Satellite (ACTS) Project invested heavily in prototype Ka-band satellite ground terminals to conduct an experiments program with the ACTS satellite. The ACTS experiment's program proposed to validate Ka-band satellite and ground station technology. demonstrate future telecommunication services. demonstrate commercial viability and market acceptability of these new services, evaluate system networking and processing technology, and characterize Ka-band propagation effects, including development of techniques to mitigate signal fading. This paper will present a summary of the fixed ground terminals developed by the NASA Glenn Research Center and its industry partners, emphasizing the technology and performance of the terminals (Part 1) and the lessons learned throughout their six year operation including the inclined orbit phase of operations (Full Report). An overview of the Ka-band technology and components developed for the ACTS ground stations is presented. Next. the performance of the ground station technology and its evolution during the ACTS campaign are discussed to illustrate the technical tradeoffs made during the program and highlight technical advances by industry to support the ACTS experiments program and terminal operations. Finally. lessons learned during development and operation of the user terminals are discussed for consideration of commercial adoption into future Ka-band systems. The fixed ground stations used for experiments by government, academic, and commercial entities used reflector based offset-fed antenna systems ranging in size from 0.35m to 3.4m antenna diameter. Gateway earth stations included two systems, referred to as the NASA Ground Station (NGS) and the Link Evaluation Terminal (LET). The NGS provides tracking, telemetry, and control (TT&C) and Time Division Multiple Access (TDMA) network control functions. The LET supports technology verification and high data rate experiments. The ground stations successfully demonstrated many services and applications at Ka-band in three different modes of operation: circuit switched TDMA using the satellite on-board processor, satellite switched SS-TDMA applications using the on-board Microwave Switch Matrix (MSM), and conventional transponder (bent-pipe) operation. Data rates ranged from 4.8 kbps up to 622 Mbps. Experiments included: 1) low rate (4.8- 1 00's kbps) remote data acquisition and control using small earth stations, 2) moderate rate (1-45 Mbps) experiments included full duplex voice and video conferencing and both full duplex and asymmetric data rate protocol and network evaluation using mid-size ground stations, and 3) link characterization experiments and high data rate (155-622 Mbps) terrestrial and satellite interoperability application experiments conducted by a consortium of experimenters using the large transportable ground stations.

An Optimizing Space Data-Communications Scheduling Method and Algorithm with Interference Mitigation, Generalized for a Broad Class of Optimization Problems

NASA Technical Reports Server (NTRS)

Rash, James

2014-01-01

NASA's space data-communications infrastructure-the Space Network and the Ground Network-provide scheduled (as well as some limited types of unscheduled) data-communications services to user spacecraft. The Space Network operates several orbiting geostationary platforms (the Tracking and Data Relay Satellite System (TDRSS)), each with its own servicedelivery antennas onboard. The Ground Network operates service-delivery antennas at ground stations located around the world. Together, these networks enable data transfer between user spacecraft and their mission control centers on Earth. Scheduling data-communications events for spacecraft that use the NASA communications infrastructure-the relay satellites and the ground stations-can be accomplished today with software having an operational heritage dating from the 1980s or earlier. An implementation of the scheduling methods and algorithms disclosed and formally specified herein will produce globally optimized schedules with not only optimized service delivery by the space data-communications infrastructure but also optimized satisfaction of all user requirements and prescribed constraints, including radio frequency interference (RFI) constraints. Evolutionary algorithms, a class of probabilistic strategies for searching large solution spaces, is the essential technology invoked and exploited in this disclosure. Also disclosed are secondary methods and algorithms for optimizing the execution efficiency of the schedule-generation algorithms themselves. The scheduling methods and algorithms as presented are adaptable to accommodate the complexity of scheduling the civilian and/or military data-communications infrastructure within the expected range of future users and space- or ground-based service-delivery assets. Finally, the problem itself, and the methods and algorithms, are generalized and specified formally. The generalized methods and algorithms are applicable to a very broad class of combinatorial-optimization problems that encompasses, among many others, the problem of generating optimal space-data communications schedules.

Space station common module network topology and hardware development

NASA Technical Reports Server (NTRS)

Anderson, P.; Braunagel, L.; Chwirka, S.; Fishman, M.; Freeman, K.; Eason, D.; Landis, D.; Lech, L.; Martin, J.; Mccorkle, J.

1990-01-01

Conceptual space station common module power management and distribution (SSM/PMAD) network layouts and detailed network evaluations were developed. Individual pieces of hardware to be developed for the SSM/PMAD test bed were identified. A technology assessment was developed to identify pieces of equipment requiring development effort. Equipment lists were developed from the previously selected network schematics. Additionally, functional requirements for the network equipment as well as other requirements which affected the suitability of specific items for use on the Space Station Program were identified. Assembly requirements were derived based on the SSM/PMAD developed requirements and on the selected SSM/PMAD network concepts. Basic requirements and simplified design block diagrams are included. DC remote power controllers were successfully integrated into the DC Marshall Space Flight Center breadboard. Two DC remote power controller (RPC) boards experienced mechanical failure of UES 706 stud-mounted diodes during mechanical installation of the boards into the system. These broken diodes caused input to output shorting of the RPC's. The UES 706 diodes were replaced on these RPC's which eliminated the problem. The DC RPC's as existing in the present breadboard configuration do not provide ground fault protection because the RPC was designed to only switch the hot side current. If ground fault protection were to be implemented, it would be necessary to design the system so the RPC switched both the hot and the return sides of power.

An Analysis for the Use of Research and Education Networks and Commercial Network Vendors in Support of Space Based Mission Critical and Non-Critical Networking

NASA Technical Reports Server (NTRS)

Bradford, Robert N.

2002-01-01

Currently, and in the past, dedicated communication circuits and "network services" with very stringent performance requirements are being used to support manned and unmanned mission critical ground operations at GSFC, JSC, MSFC, KSC and other NASA facilities. Because of the evolution of network technology, it is time to investigate using other approaches to providing mission services for space ground operations. The current NASA approach is not in keeping with the evolution of network technologies. In the past decade various research and education networks dedicated to scientific and educational endeavors have emerged, as well as commercial networking providers, that employ advanced networking technologies. These technologies have significantly changed networking in recent years. Significant advances in network routing techniques, various topologies and equipment have made commercial networks very stable and virtually error free. Advances in Dense Wave Division Multiplexing will provide tremendous amounts of bandwidth for the future. The question is: Do these networks, which are controlled and managed centrally, provide a level of service that equals the stringent NASA performance requirements. If they do, what are the implication(s) of using them for critical space based ground operations as they are, without adding high cost contractual performance requirements? A second question is the feasibility of applying the emerging grid technology in space operations. Is it feasible to develop a Space Operations Grid and/or a Space Science Grid? Since these network's connectivity is substantial, both nationally and internationally, development of these sorts of grids may be feasible. The concept of research and education networks has evolved to the international community as well. Currently there are international RENs connecting the US in Chicago to and from Europe, South America, Asia and the Pacific rim, Russia and Canada. And most countries in these areas have their own research and education network as do many states in the USA.

Space Network Ground Segment Sustainment (SGSS) Project: Developing a COTS-Intensive Ground System

NASA Technical Reports Server (NTRS)

Saylor, Richard; Esker, Linda; Herman, Frank; Jacobsohn, Jeremy; Saylor, Rick; Hoffman, Constance

2013-01-01

Purpose of the Space Network Ground Segment Sustainment (SGSS) is to implement a new modern ground segment that will enable the NASA Space Network (SN) to deliver high quality services to the SN community for the future The key SGSS Goals: (1) Re-engineer the SN ground segment (2) Enable cost efficiencies in the operability and maintainability of the broader SN.

Vibration control of building structures using self-organizing and self-learning neural networks

NASA Astrophysics Data System (ADS)

Madan, Alok

2005-11-01

Past research in artificial intelligence establishes that artificial neural networks (ANN) are effective and efficient computational processors for performing a variety of tasks including pattern recognition, classification, associative recall, combinatorial problem solving, adaptive control, multi-sensor data fusion, noise filtering and data compression, modelling and forecasting. The paper presents a potentially feasible approach for training ANN in active control of earthquake-induced vibrations in building structures without the aid of teacher signals (i.e. target control forces). A counter-propagation neural network is trained to output the control forces that are required to reduce the structural vibrations in the absence of any feedback on the correctness of the output control forces (i.e. without any information on the errors in output activations of the network). The present study shows that, in principle, the counter-propagation network (CPN) can learn from the control environment to compute the required control forces without the supervision of a teacher (unsupervised learning). Simulated case studies are presented to demonstrate the feasibility of implementing the unsupervised learning approach in ANN for effective vibration control of structures under the influence of earthquake ground motions. The proposed learning methodology obviates the need for developing a mathematical model of structural dynamics or training a separate neural network to emulate the structural response for implementation in practice.

Aeronautical-Satellite-Assisted Process Being Developed for Information Exchange Through Network Technologies (Aero-SAPIENT)

NASA Technical Reports Server (NTRS)

Zernic, Michael J.

2001-01-01

Communications technologies are being developed to address safety issues during aviation travel. Some of these technologies enable the aircraft to be in constant bidirectional communications with necessary systems, people, and other aircraft that are not currently in place today. Networking technologies, wireless datalinks, and advanced avionics techniques are areas of particular importance that the NASA Glenn Research Center has contributed. Glenn, in conjunction with the NASA Ames Research Center, NASA Dryden Flight Research Center, and NASA Langley Research Center, is investigating methods and applications that would utilize these communications technologies. In mid-June 2000, the flight readiness of the network and communications technologies were demonstrated via a simulated aircraft. A van simulating an aircraft was equipped with advanced phased-array antennas (Advanced Communications/Air Traffic Management (AC/ATM) Advanced Air Transportation Technologies (AATT) project) that used commercial Ku-band satellite communications to connect Glenn, Dryden, and Ames in a combined system ground test. This test simulated air-ground bidirectional transport of real-time digital audio, text, and video data via a hybrid network configuration that demonstrated the flight readiness of the network and communications technologies. Specifically, a Controller Pilot Data Link Communications application was used with other applications to demonstrate a multiprotocol capability via Internet-protocol encapsulated ATN (Aeronautical Telecommunications Network) data packets. The significance of this combined ground test is its contribution to the Aero Information Technology Base Program Level I milestone (Software Technology investment area) of a real-time data link for the National Airspace System. The objective of this milestone was to address multiprotocol technology applicable for real-time data links between aircraft, a satellite, and the ground as well as the ability to distribute flight data with multilevel priorities among several sites.

The telecommunications and data acquisition

NASA Technical Reports Server (NTRS)

Renzetti, N. A. (Editor)

1980-01-01

Radio astronomy and radio interferometry at microwave frequencies are discussed. Other topics concerning the Deep Space Network include program planning, planetary and interplanetary mission support, tracking and ground based navigation, communications, and station control and system technology.

GSFC network operations with Tracking and Data Relay Satellites

NASA Astrophysics Data System (ADS)

Spearing, R.; Perreten, D. E.

The Tracking and Data Relay Satellite System (TDRSS) Network (TN) has been developed to provide services to all NASA User spacecraft in near-earth orbits. Three inter-relating entities will provide these services. The TN has been transformed from a network continuously changing to meet User specific requirements to a network which is flexible to meet future needs without significant changes in operational concepts. Attention is given to the evolution of the TN network, the TN capabilities-space segment, forward link services, tracking services, return link services, the three basic capabilities, single access services, multiple access services, simulation services, the White Sands Ground Terminal, the NASA communications network, and the network control center.

GSFC network operations with Tracking and Data Relay Satellites

NASA Technical Reports Server (NTRS)

Spearing, R.; Perreten, D. E.

1984-01-01

The Tracking and Data Relay Satellite System (TDRSS) Network (TN) has been developed to provide services to all NASA User spacecraft in near-earth orbits. Three inter-relating entities will provide these services. The TN has been transformed from a network continuously changing to meet User specific requirements to a network which is flexible to meet future needs without significant changes in operational concepts. Attention is given to the evolution of the TN network, the TN capabilities-space segment, forward link services, tracking services, return link services, the three basic capabilities, single access services, multiple access services, simulation services, the White Sands Ground Terminal, the NASA communications network, and the network control center.

Integrating the automatic and the controlled: Strategies in Semantic Priming in an Attractor Network with Latching Dynamics

PubMed Central

Lerner, Itamar; Bentin, Shlomo; Shriki, Oren

2014-01-01

Semantic priming has long been recognized to reflect, along with automatic semantic mechanisms, the contribution of controlled strategies. However, previous theories of controlled priming were mostly qualitative, lacking common grounds with modern mathematical models of automatic priming based on neural networks. Recently, we have introduced a novel attractor network model of automatic semantic priming with latching dynamics. Here, we extend this work to show how the same model can also account for important findings regarding controlled processes. Assuming the rate of semantic transitions in the network can be adapted using simple reinforcement learning, we show how basic findings attributed to controlled processes in priming can be achieved, including their dependency on stimulus onset asynchrony and relatedness proportion and their unique effect on associative, category-exemplar, mediated and backward prime-target relations. We discuss how our mechanism relates to the classic expectancy theory and how it can be further extended in future developments of the model. PMID:24890261

Mapping Gnss Restricted Environments with a Drone Tandem and Indirect Position Control

NASA Astrophysics Data System (ADS)

Cledat, E.; Cucci, D. A.

2017-08-01

The problem of autonomously mapping highly cluttered environments, such as urban and natural canyons, is intractable with the current UAV technology. The reason lies in the absence or unreliability of GNSS signals due to partial sky occlusion or multi-path effects. High quality carrier-phase observations are also required in efficient mapping paradigms, such as Assisted Aerial Triangulation, to achieve high ground accuracy without the need of dense networks of ground control points. In this work we consider a drone tandem in which the first drone flies outside the canyon, where GNSS constellation is ideal, visually tracks the second drone and provides an indirect position control for it. This enables both autonomous guidance and accurate mapping of GNSS restricted environments without the need of ground control points. We address the technical feasibility of this concept considering preliminary real-world experiments in comparable conditions and we perform a mapping accuracy prediction based on a simulation scenario.

High fidelity wireless network evaluation for heterogeneous cognitive radio networks

NASA Astrophysics Data System (ADS)

Ding, Lei; Sagduyu, Yalin; Yackoski, Justin; Azimi-Sadjadi, Babak; Li, Jason; Levy, Renato; Melodia, Tammaso

2012-06-01

We present a high fidelity cognitive radio (CR) network emulation platform for wireless system tests, measure- ments, and validation. This versatile platform provides the configurable functionalities to control and repeat realistic physical channel effects in integrated space, air, and ground networks. We combine the advantages of scalable simulation environment with reliable hardware performance for high fidelity and repeatable evaluation of heterogeneous CR networks. This approach extends CR design only at device (software-defined-radio) or lower-level protocol (dynamic spectrum access) level to end-to-end cognitive networking, and facilitates low-cost deployment, development, and experimentation of new wireless network protocols and applications on frequency- agile programmable radios. Going beyond the channel emulator paradigm for point-to-point communications, we can support simultaneous transmissions by network-level emulation that allows realistic physical-layer inter- actions between diverse user classes, including secondary users, primary users, and adversarial jammers in CR networks. In particular, we can replay field tests in a lab environment with real radios perceiving and learning the dynamic environment thereby adapting for end-to-end goals over distributed spectrum coordination channels that replace the common control channel as a single point of failure. CR networks offer several dimensions of tunable actions including channel, power, rate, and route selection. The proposed network evaluation platform is fully programmable and can reliably evaluate the necessary cross-layer design solutions with configurable op- timization space by leveraging the hardware experiments to represent the realistic effects of physical channel, topology, mobility, and jamming on spectrum agility, situational awareness, and network resiliency. We also provide the flexibility to scale up the test environment by introducing virtual radios and establishing seamless signal-level interactions with real radios. This holistic wireless evaluation approach supports a large-scale, het- erogeneous, and dynamic CR network architecture and allows developing cross-layer network protocols under high fidelity, repeatable, and scalable wireless test scenarios suitable for heterogeneous space, air, and ground networks.

A Programmable SDN+NFV Architecture for UAV Telemetry Monitoring

NASA Technical Reports Server (NTRS)

White, Kyle J. S.; Pezaros, Dimitrios P.; Denney, Ewen; Knudson, Matt D.

2017-01-01

With the explosive growth in UAV numbers forecast worldwide, a core concern is how to manage the ad-hoc network configuration required for mobility management. As UAVs migrate among ground control stations, associated network services, routing and operational control must also rapidly migrate to ensure a seamless transition. In this paper, we present a novel, lightweight and modular architecture which supports high mobility, resilience and flexibility through the application of SDN and NFV principles on top of the UAV infrastructure. By combining SDN programmability and Network Function Virtualization we can achieve resilient infrastructure migration of network services, such as network monitoring and anomaly detection, coupled with migrating UAVs to enable high mobility management. Our container-based monitoring and anomaly detection Network Functions (NFs) can be tuned to specific UAV models providing operators better insight during live, high-mobility deployments. We evaluate our architecture against telemetry from over 80flights from a scientific research UAV infrastructure.

Volcano Monitoring: A Case Study in Pervasive Computing

NASA Astrophysics Data System (ADS)

Peterson, Nina; Anusuya-Rangappa, Lohith; Shirazi, Behrooz A.; Song, Wenzhan; Huang, Renjie; Tran, Daniel; Chien, Steve; Lahusen, Rick

Recent advances in wireless sensor network technology have provided robust and reliable solutions for sophisticated pervasive computing applications such as inhospitable terrain environmental monitoring. We present a case study for developing a real-time pervasive computing system, called OASIS for optimized autonomous space in situ sensor-web, which combines ground assets (a sensor network) and space assets (NASA’s earth observing (EO-1) satellite) to monitor volcanic activities at Mount St. Helens. OASIS’s primary goals are: to integrate complementary space and in situ ground sensors into an interactive and autonomous sensorweb, to optimize power and communication resource management of the sensorweb and to provide mechanisms for seamless and scalable fusion of future space and in situ components. The OASIS in situ ground sensor network development addresses issues related to power management, bandwidth management, quality of service management, topology and routing management, and test-bed design. The space segment development consists of EO-1 architectural enhancements, feedback of EO-1 data into the in situ component, command and control integration, data ingestion and dissemination and field demonstrations.

High-Capacity Ground Communications to Support Future Space Missions: A Forecast of Ground Communications Challenges in the 2010-2020 Period

NASA Technical Reports Server (NTRS)

Markley, Richard W.

2003-01-01

The purpose of this presentation is to identify major challenges involved in space ground communications networks to support space flight missions over the next 20 years. The presentation focus is on the Deep Space Network and its customers, but the forecast is applicable to all space ground communications networks.

Exploring the use of grounded theory as a methodological approach to examine the 'black box' of network leadership in the national quality forum.

PubMed

Hoflund, A Bryce

2013-01-01

This paper describes how grounded theory was used to investigate the "black box" of network leadership in the creation of the National Quality Forum. Scholars are beginning to recognize the importance of network organizations and are in the embryonic stages of collecting and analyzing data about network leadership processes. Grounded theory, with its focus on deriving theory from empirical data, offers researchers a distinctive way of studying little-known phenomena and is therefore well suited to exploring network leadership processes. Specifically, this paper provides an overview of grounded theory, a discussion of the appropriateness of grounded theory to investigating network phenomena, a description of how the research was conducted, and a discussion of the limitations and lessons learned from using this approach.

Ground-based telescope pointing and tracking optimization using a neural controller.

PubMed

Mancini, D; Brescia, M; Schipani, P

2003-01-01

Neural network models (NN) have emerged as important components for applications of adaptive control theories. Their basic generalization capability, based on acquired knowledge, together with execution rapidity and correlation ability between input stimula, are basic attributes to consider NN as an extremely powerful tool for on-line control of complex systems. By a control system point of view, not only accuracy and speed, but also, in some cases, a high level of adaptation capability is required in order to match all working phases of the whole system during its lifetime. This is particularly remarkable for a new generation ground-based telescope control system. Infact, strong changes in terms of system speed and instantaneous position error tolerance are necessary, especially in case of trajectory disturb induced by wind shake. The classical control scheme adopted in such a system is based on the proportional integral (PI) filter, already applied and implemented on a large amount of new generation telescopes, considered as a standard in this technological environment. In this paper we introduce the concept of a new approach, the neural variable structure proportional integral, (NVSPI), related to the implementation of a standard multi layer perceptron network in new generation ground-based Alt-Az telescope control systems. Its main purpose is to improve adaptive capability of the Variable structure proportional integral model, an already innovative control scheme recently introduced by authors [Proc SPIE (1997)], based on a modified version of classical PI control model, in terms of flexibility and accuracy of the dynamic response range also in presence of wind noise effects. The realization of a powerful well tested and validated telescope model simulation system allowed the possibility to directly compare performances of the two control schemes on simulated tracking trajectories, revealing extremely encouraging results in terms of NVSPI control robustness and reliability.

Below-ground carbon transfer among Betula nana may increase with warming in Arctic tundra.

PubMed

Deslippe, Julie R; Simard, Suzanne W

2011-11-01

• Shrubs are expanding in Arctic tundra, but the role of mycorrhizal fungi in this process is unknown. We tested the hypothesis that mycorrhizal networks are involved in interplant carbon (C) transfer within a tundra plant community. • Here, we installed below-ground treatments to control for C transfer pathways and conducted a (13)CO(2)-pulse-chase labelling experiment to examine C transfer among and within plant species. • We showed that mycorrhizal networks exist in tundra, and facilitate below-ground transfer of C among Betula nana individuals, but not between or within the other tundra species examined. Total C transfer among conspecific B. nana pairs was 10.7 ± 2.4% of photosynthesis, with the majority of C transferred through rhizomes or root grafts (5.2 ± 5.3%) and mycorrhizal network pathways (4.1 ± 3.3%) and very little through soil pathways (1.4 ± 0.35%). • Below-ground C transfer was of sufficient magnitude to potentially alter plant interactions in Arctic tundra, increasing the competitive ability and mono-dominance of B. nana. C transfer was significantly positively related to ambient temperatures, suggesting that it may act as a positive feedback to ecosystem change as climate warms. © 2011 The Authors. New Phytologist © 2011 New Phytologist Trust.

Untangling complex networks: risk minimization in financial markets through accessible spin glass ground states

PubMed Central

Lisewski, Andreas Martin; Lichtarge, Olivier

2010-01-01

Recurrent international financial crises inflict significant damage to societies and stress the need for mechanisms or strategies to control risk and tamper market uncertainties. Unfortunately, the complex network of market interactions often confounds rational approaches to optimize financial risks. Here we show that investors can overcome this complexity and globally minimize risk in portfolio models for any given expected return, provided the relative margin requirement remains below a critical, empirically measurable value. In practice, for markets with centrally regulated margin requirements, a rational stabilization strategy would be keeping margins small enough. This result follows from ground states of the random field spin glass Ising model that can be calculated exactly through convex optimization when relative spin coupling is limited by the norm of the network's Laplacian matrix. In that regime, this novel approach is robust to noise in empirical data and may be also broadly relevant to complex networks with frustrated interactions that are studied throughout scientific fields. PMID:20625477

Untangling complex networks: risk minimization in financial markets through accessible spin glass ground states.

PubMed

Lisewski, Andreas Martin; Lichtarge, Olivier

2010-08-15

Recurrent international financial crises inflict significant damage to societies and stress the need for mechanisms or strategies to control risk and tamper market uncertainties. Unfortunately, the complex network of market interactions often confounds rational approaches to optimize financial risks. Here we show that investors can overcome this complexity and globally minimize risk in portfolio models for any given expected return, provided the relative margin requirement remains below a critical, empirically measurable value. In practice, for markets with centrally regulated margin requirements, a rational stabilization strategy would be keeping margins small enough. This result follows from ground states of the random field spin glass Ising model that can be calculated exactly through convex optimization when relative spin coupling is limited by the norm of the network's Laplacian matrix. In that regime, this novel approach is robust to noise in empirical data and may be also broadly relevant to complex networks with frustrated interactions that are studied throughout scientific fields.

The use of virtual ground to control transmembrane voltages and measure bilayer currents in serial arrays of droplet interface bilayers

NASA Astrophysics Data System (ADS)

Sarles, Stephen A.

2013-09-01

The droplet interface bilayer (DIB) is a simple technique for constructing a stable lipid bilayer at the interface of two lipid-encased water droplets submerged in oil. Networks of DIBs formed by connecting more than two droplets constitute a new form of modular biomolecular smart material, where the transduction properties of a single lipid bilayer can affect the actions performed at other interface bilayers in the network via diffusion through the aqueous environments of shared droplet connections. The passive electrical properties of a lipid bilayer and the arrangement of droplets that determine the paths for transport in the network require specific electrical control to stimulate and interrogate each bilayer. Here, we explore the use of virtual ground for electrodes inserted into specific droplets in the network and employ a multichannel patch clamp amplifier to characterize bilayer formation and ion-channel activity in a serial DIB array. Analysis of serial connections of DIBs is discussed to understand how assigning electrode connections to the measurement device can be used to measure activity across all lipid membranes within a network. Serial arrays of DIBs are assembled using the regulated attachment method within a multi-compartment flexible substrate, and wire-type electrodes inserted into each droplet compartment of the substrate enable the application of voltage and measurement of current in each droplet in the array.

Developing a space network interface simulator: The NTS approach

NASA Technical Reports Server (NTRS)

Hendrzak, Gary E.

1993-01-01

This paper describes the approach used to redevelop the Network Control Center (NCC) Test System (NTS), a hardware and software facility designed to make testing of the NCC Data System (NCCDS) software efficient, effective, and as rigorous as possible prior to operational use. The NTS transmits and receives network message traffic in real-time. Data transfer rates and message content are strictly controlled and are identical to that of the operational systems. NTS minimizes the need for costly and time-consuming testing with the actual external entities (e.g., the Hubble Space Telescope (HST) Payload Operations Control Center (POCC) and the White Sands Ground Terminal). Discussed are activities associated with the development of the NTS, lessons learned throughout the project's lifecycle, and resulting productivity and quality increases.

Implementation of the MSAT network in Canada

NASA Astrophysics Data System (ADS)

Roscoe, Orest S.

1991-10-01

MSAT will be launched into geostationary orbit at 106.5 degrees west longitude. It will have an aggregate EIRP in excess of 57 dBw, making it the highest powered mobile satellite launched or planned to date. The MSAT ground segment will comprise hundreds of thousands of mobile terminals, as well as numerous feederlink earth stations. This requires a large scale network control system which is unprecedented in a satellite environment. The network control system must support circuit-switched voice and data services and packet-switched data services. In addition to assignment of capacity on demand, the control system must be able to support a variety of service features required by customers, as well as record information for billing. It must operate in a multi-beam, multi-satellite environment as the system grows.

Machine Learning Technique to Find Quantum Many-Body Ground States of Bosons on a Lattice

NASA Astrophysics Data System (ADS)

Saito, Hiroki; Kato, Masaya

2018-01-01

We have developed a variational method to obtain many-body ground states of the Bose-Hubbard model using feedforward artificial neural networks. A fully connected network with a single hidden layer works better than a fully connected network with multiple hidden layers, and a multilayer convolutional network is more efficient than a fully connected network. AdaGrad and Adam are optimization methods that work well. Moreover, we show that many-body ground states with different numbers of particles can be generated by a single network.

Disaster management and mitigation: the telecommunications infrastructure.

PubMed

Patricelli, Frédéric; Beakley, James E; Carnevale, Angelo; Tarabochia, Marcello; von Lubitz, Dag K J E

2009-03-01

Among the most typical consequences of disasters is the near or complete collapse of terrestrial telecommunications infrastructures (especially the distribution network--the 'last mile') and their concomitant unavailability to the rescuers and the higher echelons of mitigation teams. Even when such damage does not take place, the communications overload/congestion resulting from significantly elevated traffic generated by affected residents can be highly disturbing. The paper proposes innovative remedies to the telecommunications difficulties in disaster struck regions. The offered solutions are network-centric operations-cap able, and can be employed in management of disasters of any magnitude (local to national or international). Their implementation provide ground rescue teams (such as law enforcement, firemen, healthcare personnel, civilian authorities) with tactical connectivity among themselves, and, through the Next Generation Network backbone, ensure the essential bidirectional free flow of information and distribution of Actionable Knowledge among ground units, command/control centres, and civilian and military agencies participating in the rescue effort.

Data Gathering and Energy Transfer Dilemma in UAV-Assisted Flying Access Network for IoT.

PubMed

Arabi, Sara; Sabir, Essaid; Elbiaze, Halima; Sadik, Mohamed

2018-05-11

Recently, Unmanned Aerial Vehicles (UAVs) have emerged as an alternative solution to assist wireless networks, thanks to numerous advantages they offer in comparison to terrestrial fixed base stations. For instance, a UAV can be used to embed a flying base station providing an on-demand nomadic access to network services. A UAV can also be used to wirelessly recharge out-of-battery ground devices. In this paper, we aim to deal with both data collection and recharging depleted ground Internet-of-Things (IoT) devices through a UAV station used as a flying base station. To extend the network lifetime, we present a novel use of UAV with energy harvesting module and wireless recharging capabilities. However, the UAV is used as an energy source to empower depleted IoT devices. On one hand, the UAV charges depleted ground IoT devices under three policies: (1) low-battery first scheme; (2) high-battery first scheme; and (3) random scheme. On the other hand, the UAV station collects data from IoT devices that have sufficient energy to transmit their packets, and in the same phase, the UAV exploits the Radio Frequency (RF) signals transmitted by IoT devices to extract and harvest energy. Furthermore, and as the UAV station has a limited coverage time due to its energy constraints, we propose and investigate an efficient trade-off between ground users recharging time and data gathering time. Furthermore, we suggest to control and optimize the UAV trajectory in order to complete its travel within a minimum time, while minimizing the energy spent and/or enhancing the network lifetime. Extensive numerical results and simulations show how the system behaves under different scenarios and using various metrics in which we examine the added value of UAV with energy harvesting module.

The analysis of transient noise of PCB P/G network based on PI/SI co-simulation

NASA Astrophysics Data System (ADS)

Haohang, Su

2018-02-01

With the frequency of the space camera become higher than before, the power noise of the imaging electronic system become the important factor. Much more power noise would disturb the transmissions signal, and even influence the image sharpness and system noise. "Target impedance method" is one of the traditional design method of P/G network (power and ground network), which is shorted of transient power noise analysis and often made "over design". In this paper, a new design method of P/G network is provided which simulated by PI/SI co-simulation. The transient power noise can be simulated and then applied in the design of noise reduction, thus effectively controlling the change of the noise in the P/G network. The method can efficiently control the number of adding decoupling capacitor, and is very efficient and feasible to keep the power integrity.

Study of mobile satellite network based on GEO/LEO satellite constellation

NASA Astrophysics Data System (ADS)

Hu, Xiulin; Zeng, Yujiang; Wang, Ying; Wang, Xianhui

2005-11-01

Mobile satellite network with Inter Satellite Links (ISLs), which consists of non-geostationary satellites, has the characteristic of network topology's variability. This is a great challenge to the design and management of mobile satellite network. This paper analyzes the characteristics of mobile satellite network, takes multimedia Quality of Service (QoS) as the chief object and presents a reference model based on Geostationary Earth Orbit (GEO)/ Low Earth Orbit (LEO) satellite constellation which adapts to the design and management of mobile satellite network. In the reference model, LEO satellites constitute service subnet with responsibility for the access, transmission and switch of the multimedia services for mobile users, while GEO satellites constitute management subnet taking on the centralized management to service subnet. Additionally ground control centre realizes the whole monitoring and control via management subnet. Comparing with terrestrial network, the above reference model physically separates management subnet from service subnet, which not only enhances the advantage of centralized management but also overcomes the shortcoming of low reliability in terrestrial network. Routing of mobile satellite network based on GEO/LEO satellite constellation is also discussed in this paper.

The IXV Ground Segment design, implementation and operations

NASA Astrophysics Data System (ADS)

Martucci di Scarfizzi, Giovanni; Bellomo, Alessandro; Musso, Ivano; Bussi, Diego; Rabaioli, Massimo; Santoro, Gianfranco; Billig, Gerhard; Gallego Sanz, José María

2016-07-01

The Intermediate eXperimental Vehicle (IXV) is an ESA re-entry demonstrator that performed, on the 11th February of 2015, a successful re-entry demonstration mission. The project objectives were the design, development, manufacturing and on ground and in flight verification of an autonomous European lifting and aerodynamically controlled re-entry system. For the IXV mission a dedicated Ground Segment was provided. The main subsystems of the IXV Ground Segment were: IXV Mission Control Center (MCC), from where monitoring of the vehicle was performed, as well as support during pre-launch and recovery phases; IXV Ground Stations, used to cover IXV mission by receiving spacecraft telemetry and forwarding it toward the MCC; the IXV Communication Network, deployed to support the operations of the IXV mission by interconnecting all remote sites with MCC, supporting data, voice and video exchange. This paper describes the concept, architecture, development, implementation and operations of the ESA Intermediate Experimental Vehicle (IXV) Ground Segment and outlines the main operations and lessons learned during the preparation and successful execution of the IXV Mission.

Advanced wireless mobile collaborative sensing network for tactical and strategic missions

NASA Astrophysics Data System (ADS)

Xu, Hao

2017-05-01

In this paper, an advanced wireless mobile collaborative sensing network will be developed. Through properly combining wireless sensor network, emerging mobile robots and multi-antenna sensing/communication techniques, we could demonstrate superiority of developed sensing network. To be concrete, heterogeneous mobile robots including unmanned aerial vehicle (UAV) and unmanned ground vehicle (UGV) are equipped with multi-model sensors and wireless transceiver antennas. Through real-time collaborative formation control, multiple mobile robots can team the best formation that can provide most accurate sensing results. Also, formatting multiple mobile robots can also construct a multiple-input multiple-output (MIMO) communication system that can provide a reliable and high performance communication network.

Feedback enhances feedforward figure-ground segmentation by changing firing mode.

PubMed

Supèr, Hans; Romeo, August

2011-01-01

In the visual cortex, feedback projections are conjectured to be crucial in figure-ground segregation. However, the precise function of feedback herein is unclear. Here we tested a hypothetical model of reentrant feedback. We used a previous developed 2-layered feedforward spiking network that is able to segregate figure from ground and included feedback connections. Our computer model data show that without feedback, neurons respond with regular low-frequency (∼9 Hz) bursting to a figure-ground stimulus. After including feedback the firing pattern changed into a regular (tonic) spiking pattern. In this state, we found an extra enhancement of figure responses and a further suppression of background responses resulting in a stronger figure-ground signal. Such push-pull effect was confirmed by comparing the figure-ground responses with the responses to a homogenous texture. We propose that feedback controls figure-ground segregation by influencing the neural firing patterns of feedforward projecting neurons.

Land subsidence caused by ground water withdrawal in urban areas

USGS Publications Warehouse

Holzer, T.L.; Johnson, A.I.

1985-01-01

At least eight urban areas in the world have encountered significant economic impact from land subsidence caused by pumping of ground water from unconsolidated sediment. The areas, most of which are coastal, include Bangkok, Houston, Mexico City, Osaka, San Jose, Shanghai, Tokyo, and Venice. Flooding related to decreased ground elevation is the principal adverse effect of the subsidence. Lesser effects include regional tilting, well-casing failures, "rising" buildings, and ground failure or rupture. Subsidence of most of these urban areas began before the phenomenon was discovered and understood. Thus, the subsidence problems were unanticipated. Methods to arrest subsidence typically have included control of ground water pumping and development of surface water to offset the reductions of ground water pumping. Ground water recharge has also been practiced. Areas threatened by flooding have been protected by extensive networks of dikes and sea walls, locks, and pumping stations to remove storm runoff. ?? 1985 D. Reidel Publishing Company.

Coarse-Grain Bandwidth Estimation Scheme for Large-Scale Network

NASA Technical Reports Server (NTRS)

Cheung, Kar-Ming; Jennings, Esther H.; Sergui, John S.

2013-01-01

A large-scale network that supports a large number of users can have an aggregate data rate of hundreds of Mbps at any time. High-fidelity simulation of a large-scale network might be too complicated and memory-intensive for typical commercial-off-the-shelf (COTS) tools. Unlike a large commercial wide-area-network (WAN) that shares diverse network resources among diverse users and has a complex topology that requires routing mechanism and flow control, the ground communication links of a space network operate under the assumption of a guaranteed dedicated bandwidth allocation between specific sparse endpoints in a star-like topology. This work solved the network design problem of estimating the bandwidths of a ground network architecture option that offer different service classes to meet the latency requirements of different user data types. In this work, a top-down analysis and simulation approach was created to size the bandwidths of a store-and-forward network for a given network topology, a mission traffic scenario, and a set of data types with different latency requirements. These techniques were used to estimate the WAN bandwidths of the ground links for different architecture options of the proposed Integrated Space Communication and Navigation (SCaN) Network. A new analytical approach, called the "leveling scheme," was developed to model the store-and-forward mechanism of the network data flow. The term "leveling" refers to the spreading of data across a longer time horizon without violating the corresponding latency requirement of the data type. Two versions of the leveling scheme were developed: 1. A straightforward version that simply spreads the data of each data type across the time horizon and doesn't take into account the interactions among data types within a pass, or between data types across overlapping passes at a network node, and is inherently sub-optimal. 2. Two-state Markov leveling scheme that takes into account the second order behavior of the store-and-forward mechanism, and the interactions among data types within a pass. The novelty of this approach lies in the modeling of the store-and-forward mechanism of each network node. The term store-and-forward refers to the data traffic regulation technique in which data is sent to an intermediate network node where they are temporarily stored and sent at a later time to the destination node or to another intermediate node. Store-and-forward can be applied to both space-based networks that have intermittent connectivity, and ground-based networks with deterministic connectivity. For groundbased networks, the store-and-forward mechanism is used to regulate the network data flow and link resource utilization such that the user data types can be delivered to their destination nodes without violating their respective latency requirements.

Catchment-Scale Terrain Modelling with Structure-from-Motion Photogrammetry: a replacement for airborne lidar?

NASA Astrophysics Data System (ADS)

Brasington, James; James, Joe; Cook, Simon; Cox, Simon; Lotsari, Eliisa; McColl, Sam; Lehane, Niall; Williams, Richard; Vericat, Damia

2016-04-01

In recent years, 3D terrain reconstructions based on Structure-from-Motion photogrammetry have dramatically democratized the availability of high quality topographic data. This approach involves the use of a non-linear bundle adjustment to estimate simultaneously camera position, pose, distortion and 3D model coordinates. In contrast to traditional aerial photogrammetry, the bundle adjustment is typically solved without external constraints and instead ground control is used a posteriori to transform the modelled coordinates to an established datum using a similarity transformation. The limited data requirements, coupled with the ability to self-calibrate compact cameras, has led to a burgeoning of applications using low-cost imagery acquired terrestrially or from low-altitude platforms. To date, most applications have focused on relatively small spatial scales (0.1-5 Ha), where relaxed logistics permit the use of dense ground control networks and high resolution, close-range photography. It is less clear whether this low-cost approach can be successfully upscaled to tackle larger, watershed-scale projects extending over 102-3 km2 where it could offer a competitive alternative to established landscape modelling with airborne lidar. At such scales, compromises over the density of ground control, the speed and height of sensor platform and related image properties are inevitable. In this presentation we provide a systematic assessment of the quality of large-scale SfM terrain products derived for over 80 km2 of the braided Dart River and its catchment in the Southern Alps of NZ. Reference data in the form of airborne and terrestrial lidar are used to quantify the quality of 3D reconstructions derived from helicopter photography and used to establish baseline uncertainty models for geomorphic change detection. Results indicate that camera network design is a key determinant of model quality, and that standard aerial photogrammetric networks based on strips of nadir photography can lead to unstable camera calibration and systematic errors that are difficult to model with sparse ground control. We demonstrate how a low cost multi-camera platform providing both nadir and oblique imagery can support robust camera calibration, enabling the generation of high quality, large-scale terrain products that are suitable for precision fluvial change detection.

Wireless Command-and-Control of UAV-Based Imaging LANs

NASA Technical Reports Server (NTRS)

Herwitz, Stanley; Dunagan, S. E.; Sullivan, D. V.; Slye, R. E.; Leung, J. G.; Johnson, L. F.

2006-01-01

Dual airborne imaging system networks were operated using a wireless line-of-sight telemetry system developed as part of a 2002 unmanned aerial vehicle (UAV) imaging mission over the USA s largest coffee plantation on the Hawaiian island of Kauai. A primary mission objective was the evaluation of commercial-off-the-shelf (COTS) 802.11b wireless technology for reduction of payload telemetry costs associated with UAV remote sensing missions. Predeployment tests with a conventional aircraft demonstrated successful wireless broadband connectivity between a rapidly moving airborne imaging local area network (LAN) and a fixed ground station LAN. Subsequently, two separate LANs with imaging payloads, packaged in exterior-mounted pressure pods attached to the underwing of NASA's Pathfinder-Plus UAV, were operated wirelessly by ground-based LANs over independent Ethernet bridges. Digital images were downlinked from the solar-powered aircraft at data rates of 2-6 megabits per second (Mbps) over a range of 6.5 9.5 km. An integrated wide area network enabled payload monitoring and control through the Internet from a range of ca. 4000 km during parts of the mission. The recent advent of 802.11g technology is expected to boost the system data rate by about a factor of five.

Re-engineering Nascom's network management architecture

NASA Technical Reports Server (NTRS)

Drake, Brian C.; Messent, David

1994-01-01

The development of Nascom systems for ground communications began in 1958 with Project Vanguard. The low-speed systems (rates less than 9.6 Kbs) were developed following existing standards; but, there were no comparable standards for high-speed systems. As a result, these systems were developed using custom protocols and custom hardware. Technology has made enormous strides since the ground support systems were implemented. Standards for computer equipment, software, and high-speed communications exist and the performance of current workstations exceeds that of the mainframes used in the development of the ground systems. Nascom is in the process of upgrading its ground support systems and providing additional services. The Message Switching System (MSS), Communications Address Processor (CAP), and Multiplexer/Demultiplexer (MDM) Automated Control System (MACS) are all examples of Nascom systems developed using standards such as, X-windows, Motif, and Simple Network Management Protocol (SNMP). Also, the Earth Observing System (EOS) Communications (Ecom) project is stressing standards as an integral part of its network. The move towards standards has produced a reduction in development, maintenance, and interoperability costs, while providing operational quality improvement. The Facility and Resource Manager (FARM) project has been established to integrate the Nascom networks and systems into a common network management architecture. The maximization of standards and implementation of computer automation in the architecture will lead to continued cost reductions and increased operational efficiency. The first step has been to derive overall Nascom requirements and identify the functionality common to all the current management systems. The identification of these common functions will enable the reuse of processes in the management architecture and promote increased use of automation throughout the Nascom network. The MSS, CAP, MACS, and Ecom projects have indicated the potential value of commercial-off-the-shelf (COTS) and standards through reduced cost and high quality. The FARM will allow the application of the lessons learned from these projects to all future Nascom systems.

A research on the application of software defined networking in satellite network architecture

NASA Astrophysics Data System (ADS)

Song, Huan; Chen, Jinqiang; Cao, Suzhi; Cui, Dandan; Li, Tong; Su, Yuxing

2017-10-01

Software defined network is a new type of network architecture, which decouples control plane and data plane of traditional network, has the feature of flexible configurations and is a direction of the next generation terrestrial Internet development. Satellite network is an important part of the space-ground integrated information network, while the traditional satellite network has the disadvantages of difficult network topology maintenance and slow configuration. The application of SDN technology in satellite network can solve these problems that traditional satellite network faces. At present, the research on the application of SDN technology in satellite network is still in the stage of preliminary study. In this paper, we start with introducing the SDN technology and satellite network architecture. Then we mainly introduce software defined satellite network architecture, as well as the comparison of different software defined satellite network architecture and satellite network virtualization. Finally, the present research status and development trend of SDN technology in satellite network are analyzed.

A laboratory system for the investigation of rain fade compensation techniques for Ka-band satellites

NASA Technical Reports Server (NTRS)

Svoboda, James S.; Kachmar, Brian A.

1993-01-01

The design and performance of a rain fade simulation/counteraction system on a laboratory simulated 30/20 GHz, time division multiple access (TDMA) satellite communications testbed is evaluated. Severe rain attenuation of electromagnetic radiation at 30/20 GHz occurs due to the carrier wavelength approaching the water droplet size. Rain in the downlink path lowers the signal power present at the receiver, resulting in a higher number of bit errors induced in the digital ground terminal. The laboratory simulation performed at NASA Lewis Research Center uses a programmable PIN diode attenuator to simulate 20 GHz satellite downlink geographic rain fade profiles. A computer based network control system monitors the downlink power and informs the network of any power threshold violations, which then prompts the network to issue commands that temporarily increase the gain of the satellite based traveling wave tube (TWT) amplifier. After the rain subsides, the network returns the TWT to the normal energy conserving power mode. Bit error rate (BER) data taken at the receiving ground terminal serves as a measure of the severity of rain degradation, and also evaluates the extent to which the network can improve the faded channel.

The Telecommunications and Data Acquisition Report

NASA Technical Reports Server (NTRS)

Posner, E. C. (Editor)

1984-01-01

This publication provides reports on work performed for the Office of Space Tracking and Data Systems (OSTDS). It reports on the activities of the deep space network (DSN) and the Ground Communications Facility (GCF). Topics discussed on the operation of the DSN include: (1) spacecraft-ground communications; (2) station control and system technology; and (3) capabilities for new projects for systems implementation. The GCF compatibility with packets and data compression is discussed. In geodynamics, the publication reports on the application of radio interferometry at microwave frequencies for geodynamic measurements.

Ground-based simulation of telepresence for materials science experiments. [remote viewing and control of processes aboard Space Station

NASA Technical Reports Server (NTRS)

Johnston, James C.; Rosenthal, Bruce N.; Bonner, Mary JO; Hahn, Richard C.; Herbach, Bruce

1989-01-01

A series of ground-based telepresence experiments have been performed to determine the minimum video frame rate and resolution required for the successive performance of materials science experiments in space. The approach used is to simulate transmission between earth and space station with transmission between laboratories on earth. The experiments include isothermal dendrite growth, physical vapor transport, and glass melting. Modifications of existing apparatus, software developed, and the establishment of an inhouse network are reviewed.

U.S. Army Dugway Proving Ground, UT and the West Desert Test Center

DTIC Science & Technology

2001-04-30

Optic Network •32 Channels of Video •7 Communications Consoles with 20 Radio Nets and Phone Patch •Over 40 Communication Drops & Cell Phones •Centralized... Phone Tower Sites Cell Phone Activation May ‘01 Logistical Support Full Serv ice Com mun ity l Ground Transportation and Maintenance – Vehicle Support...Voice, Data & Video Communications in Mission Control Center •Data Speed: 100 MB/sec •Ethernet Connections •Commercial Power to most Sites Cell

JPL control/structure interaction test bed real-time control computer architecture

NASA Technical Reports Server (NTRS)

Briggs, Hugh C.

1989-01-01

The Control/Structure Interaction Program is a technology development program for spacecraft that exhibit interactions between the control system and structural dynamics. The program objectives include development and verification of new design concepts - such as active structure - and new tools - such as combined structure and control optimization algorithm - and their verification in ground and possibly flight test. A focus mission spacecraft was designed based upon a space interferometer and is the basis for design of the ground test article. The ground test bed objectives include verification of the spacecraft design concepts, the active structure elements and certain design tools such as the new combined structures and controls optimization tool. In anticipation of CSI technology flight experiments, the test bed control electronics must emulate the computation capacity and control architectures of space qualifiable systems as well as the command and control networks that will be used to connect investigators with the flight experiment hardware. The Test Bed facility electronics were functionally partitioned into three units: a laboratory data acquisition system for structural parameter identification and performance verification; an experiment supervisory computer to oversee the experiment, monitor the environmental parameters and perform data logging; and a multilevel real-time control computing system. The design of the Test Bed electronics is presented along with hardware and software component descriptions. The system should break new ground in experimental control electronics and is of interest to anyone working in the verification of control concepts for large structures.

Standard interface: Twin-coaxial converter

NASA Technical Reports Server (NTRS)

Lushbaugh, W. A.

1976-01-01

The network operations control center standard interface has been adopted as a standard computer interface for all future minicomputer based subsystem development for the Deep Space Network. Discussed is an intercomputer communications link using a pair of coaxial cables. This unit is capable of transmitting and receiving digital information at distances up to 600 m with complete ground isolation between the communicating devices. A converter is described that allows a computer equipped with the standard interface to use the twin coaxial link.

Characterizing Social Interaction in Tobacco-Oriented Social Networks: An Empirical Analysis.

PubMed

Liang, Yunji; Zheng, Xiaolong; Zeng, Daniel Dajun; Zhou, Xingshe; Leischow, Scott James; Chung, Wingyan

2015-06-19

Social media is becoming a new battlefield for tobacco "wars". Evaluating the current situation is very crucial for the advocacy of tobacco control in the age of social media. To reveal the impact of tobacco-related user-generated content, this paper characterizes user interaction and social influence utilizing social network analysis and information theoretic approaches. Our empirical studies demonstrate that the exploding pro-tobacco content has long-lasting effects with more active users and broader influence, and reveal the shortage of social media resources in global tobacco control. It is found that the user interaction in the pro-tobacco group is more active, and user-generated content for tobacco promotion is more successful in obtaining user attention. Furthermore, we construct three tobacco-related social networks and investigate the topological patterns of these tobacco-related social networks. We find that the size of the pro-tobacco network overwhelms the others, which suggests a huge number of users are exposed to the pro-tobacco content. These results indicate that the gap between tobacco promotion and tobacco control is widening and tobacco control may be losing ground to tobacco promotion in social media.

Characterizing Social Interaction in Tobacco-Oriented Social Networks: An Empirical Analysis

PubMed Central

Liang, Yunji; Zheng, Xiaolong; Zeng, Daniel Dajun; Zhou, Xingshe; Leischow, Scott James; Chung, Wingyan

2015-01-01

Social media is becoming a new battlefield for tobacco “wars”. Evaluating the current situation is very crucial for the advocacy of tobacco control in the age of social media. To reveal the impact of tobacco-related user-generated content, this paper characterizes user interaction and social influence utilizing social network analysis and information theoretic approaches. Our empirical studies demonstrate that the exploding pro-tobacco content has long-lasting effects with more active users and broader influence, and reveal the shortage of social media resources in global tobacco control. It is found that the user interaction in the pro-tobacco group is more active, and user-generated content for tobacco promotion is more successful in obtaining user attention. Furthermore, we construct three tobacco-related social networks and investigate the topological patterns of these tobacco-related social networks. We find that the size of the pro-tobacco network overwhelms the others, which suggests a huge number of users are exposed to the pro-tobacco content. These results indicate that the gap between tobacco promotion and tobacco control is widening and tobacco control may be losing ground to tobacco promotion in social media. PMID:26091553

An analytical method to determine ground water supply well network designs.

PubMed

MacMillan, Gordon James

2009-01-01

An analytical method is provided where the ground water practitioner can quickly determine the size (number of wells) and spacing of a well network capable of meeting a known ground water demand. In order to apply the method, two new parameters are derived that relate theoretical drawdown to the maximum drawdown that is achievable without mining the aquifer. The size of a well network is shown to be proportional to the ground water demand and inversely proportional to the transmissivity and available head. The spacing between wells in a supply well network is shown to be most sensitive to a derived parameter r(HA/3) , which is related to the available head and the propagation of drawdown away from a theoretical well if the total ground water demand was applied to that well. The method can be used to quickly determine the required spacing between wells in well networks of various sizes that are completed in confined aquifers with no leakance. Copyright © 2009 The Author(s). Journal Compilation © 2009 National Ground Water Association.

Asynchronous transfer mode link performance over ground networks

NASA Technical Reports Server (NTRS)

Chow, E. T.; Markley, R. W.

1993-01-01

The results of an experiment to determine the feasibility of using asynchronous transfer mode (ATM) technology to support advanced spacecraft missions that require high-rate ground communications and, in particular, full-motion video are reported. Potential nodes in such a ground network include Deep Space Network (DSN) antenna stations, the Jet Propulsion Laboratory, and a set of national and international end users. The experiment simulated a lunar microrover, lunar lander, the DSN ground communications system, and distributed science users. The users were equipped with video-capable workstations. A key feature was an optical fiber link between two high-performance workstations equipped with ATM interfaces. Video was also transmitted through JPL's institutional network to a user 8 km from the experiment. Variations in video depending on the networks and computers were observed, the results are reported.

US GEOLOGICAL SURVEY'S NATIONAL SYSTEM FOR PROCESSING AND DISTRIBUTION OF NEAR REAL-TIME HYDROLOGICAL DATA.

USGS Publications Warehouse

Shope, William G.; ,

1987-01-01

The US Geological Survey is utilizing a national network of more than 1000 satellite data-collection stations, four satellite-relay direct-readout ground stations, and more than 50 computers linked together in a private telecommunications network to acquire, process, and distribute hydrological data in near real-time. The four Survey offices operating a satellite direct-readout ground station provide near real-time hydrological data to computers located in other Survey offices through the Survey's Distributed Information System. The computerized distribution system permits automated data processing and distribution to be carried out in a timely manner under the control and operation of the Survey office responsible for the data-collection stations and for the dissemination of hydrological information to the water-data users.

Advanced ground station architecture

NASA Technical Reports Server (NTRS)

Zillig, David; Benjamin, Ted

1994-01-01

This paper describes a new station architecture for NASA's Ground Network (GN). The architecture makes efficient use of emerging technologies to provide dramatic reductions in size, operational complexity, and operational and maintenance costs. The architecture, which is based on recent receiver work sponsored by the Office of Space Communications Advanced Systems Program, allows integration of both GN and Space Network (SN) modes of operation in the same electronics system. It is highly configurable through software and the use of charged coupled device (CCD) technology to provide a wide range of operating modes. Moreover, it affords modularity of features which are optional depending on the application. The resulting system incorporates advanced RF, digital, and remote control technology capable of introducing significant operational, performance, and cost benefits to a variety of NASA communications and tracking applications.

The automated ground network system

NASA Technical Reports Server (NTRS)

Smith, Miles T.; Militch, Peter N.

1993-01-01

The primary goal of the Automated Ground Network System (AGNS) project is to reduce Ground Network (GN) station life-cycle costs. To accomplish this goal, the AGNS project will employ an object-oriented approach to develop a new infrastructure that will permit continuous application of new technologies and methodologies to the Ground Network's class of problems. The AGNS project is a Total Quality (TQ) project. Through use of an open collaborative development environment, developers and users will have equal input into the end-to-end design and development process. This will permit direct user input and feedback and will enable rapid prototyping for requirements clarification. This paper describes the AGNS objectives, operations concept, and proposed design.

Wireless canopy sensing network systems for automated control of irrigation and water use efficiency

USDA-ARS?s Scientific Manuscript database

Ground-based instrumentation for plant canopy sensing (infrared thermometry and spectral reflectance sensors) has been used extensively in agriculture to monitor crop status. Typically, measurements are accomplished with handheld or vehicle mounted instrumentation during limited periods of a day, an...

Exploring the impact of big data in economic geology using cloud-based synthetic sensor networks

NASA Astrophysics Data System (ADS)

Klump, J. F.; Robertson, J.

2015-12-01

In a market demanding lower resource prices and increasing efficiencies, resources companies are increasingly looking to the realm of real-time, high-frequency data streams to better measure and manage their minerals processing chain, from pit to plant to port. Sensor streams can include real-time drilling engineering information, data streams from mining trucks, and on-stream sensors operating in the plant feeding back rich chemical information. There are also many opportunities to deploy new sensor streams - unlike environmental monitoring networks, the mine environment is not energy- or bandwidth-limited. Although the promised efficiency dividends are inviting, the path to achieving these is difficult to see for most companies. As well as knowing where to invest in new sensor technology and how to integrate the new data streams, companies must grapple with risk-laden changes to their established methods of control to achieve maximum gains. What is required is a sandbox data environment for the development of analysis and control strategies at scale, allowing companies to de-risk proposed changes before actually deploying them to a live mine environment. In this presentation we describe our approach to simulating real-time scaleable data streams in a mine environment. Our sandbox consists of three layers: (a) a ground-truth layer that contains geological models, which can be statistically based on historical operations data, (b) a measurement layer - a network of RESTful synthetic sensor microservices which can simulate measurements of ground-truth properties, and (c) a control layer, which integrates the sensor streams and drives the measurement and optimisation strategies. The control layer could be a new machine learner, or simply a company's existing data infrastructure. Containerisation allows rapid deployment of large numbers of sensors, as well as service discovery to form a dynamic network of thousands of sensors, at a far lower cost than physically building the network.

A Gradient Optimization Approach to Adaptive Multi-Robot Control

DTIC Science & Technology

2009-09-01

implemented for deploying a group of three flying robots with downward facing cameras to monitor an environment on the ground. Thirdly, the multi-robot...theoretically proven, and implemented on multi-robot platforms. Thesis Supervisor: Daniela Rus Title: Professor of Electrical Engineering and Computer...often nonlinear, and they are coupled through a network which changes over time. Thirdly, implementing multi-robot controllers requires maintaining mul

Untangling complex networks: Risk minimization in financial markets through accessible spin glass ground states

NASA Astrophysics Data System (ADS)

Lisewski, Andreas Martin; Lichtarge, Olivier

2010-08-01

Recurrent international financial crises inflict significant damage to societies and stress the need for mechanisms or strategies to control risk and tamper market uncertainties. Unfortunately, the complex network of market interactions often confounds rational approaches to optimize financial risks. Here we show that investors can overcome this complexity and globally minimize risk in portfolio models for any given expected return, provided the margin requirement remains below a critical, empirically measurable value. In practice, for markets with centrally regulated margin requirements, a rational stabilization strategy would be keeping margins small enough. This result follows from ground states of the random field spin glass Ising model that can be calculated exactly through convex optimization when relative spin coupling is limited by the norm of the network’s Laplacian matrix. In that regime, this novel approach is robust to noise in empirical data and may be also broadly relevant to complex networks with frustrated interactions that are studied throughout scientific fields.

Hail prevention by ground-based silver iodide generators: Results of historical and modern field projects

NASA Astrophysics Data System (ADS)

Dessens, J.; Sánchez, J. L.; Berthet, C.; Hermida, L.; Merino, A.

2016-03-01

The science of hail suppression by silver iodide (AgI) cloud seeding was developed during the second half of the 20th century in laboratory and tested in several research or operational projects using three delivery methods for the ice forming particles: ground generators, aircraft, and rockets. The randomization process for the seeding was often considered as the imperative method for a better evaluation but failed to give firm results, mostly because the projects did not last long enough considering the hazardous occurrence of severe hailfalls, and also probably due to the use of improper hail parameters. At the same time and until now, a continuous long-term research and operational field project (1952-2015) using ground generator networks has been conducted in France under the leadership of the Association Nationale d'Etude et de Lutte contre les Fléaux Atmosphériques (ANELFA), with a control initially based on annual insurance loss-to-risk ratios, then on hailpad data. More recently (2000-2009), a companion ground seeding project was developed in the north of Spain, with control mostly based on microphysical and hailpad data. The present paper, which focuses on hail suppression by ground seeding, reviews the production of the AgI nuclei, their dispersion and measurement in the atmosphere, as well as their observed or simulated effects in clouds. The paper summarizes the results of the main historical projects in Switzerland, Argentina, and North America, and finally concentrates on the current French and Spanish projects, with a review of already published results, complemented by new ones recently collected in Spain. The conclusion, at least for France and Spain, is that if ground seeding is performed starting 3 hours before the hail falls at the ground with a 10-km mesh AgI generator network located in the developing hailstorm areas, each generator burning about 9 g of AgI per hour, the hailfall energy of the most severe hail days is decreased by about 50%.

LEO Download Capacity Analysis for a Network of Adaptive Array Ground Stations

NASA Technical Reports Server (NTRS)

Ingram, Mary Ann; Barott, William C.; Popovic, Zoya; Rondineau, Sebastien; Langley, John; Romanofsky, Robert; Lee, Richard Q.; Miranda, Felix; Steffes, Paul; Mandl, Dan

2005-01-01

To lower costs and reduce latency, a network of adaptive array ground stations, distributed across the United States, is considered for the downlink of a polar-orbiting low earth orbiting (LEO) satellite. Assuming the X-band 105 Mbps transmitter of NASA s Earth Observing 1 (EO-1) satellite with a simple line-of-sight propagation model, the average daily download capacity in bits for a network of adaptive array ground stations is compared to that of a single 11 m dish in Poker Flats, Alaska. Each adaptive array ground station is assumed to have multiple steerable antennas, either mechanically steered dishes or phased arrays that are mechanically steered in azimuth and electronically steered in elevation. Phased array technologies that are being developed for this application are the space-fed lens (SFL) and the reflectarray. Optimization of the different boresight directions of the phased arrays within a ground station is shown to significantly increase capacity; for example, this optimization quadruples the capacity for a ground station with eight SFLs. Several networks comprising only two to three ground stations are shown to meet or exceed the capacity of the big dish, Cutting the data rate by half, which saves modem costs and increases the coverage area of each ground station, is shown to increase the average daily capacity of the network for some configurations.

Performance analysis of Aloha networks with power capture and near/far effect

NASA Astrophysics Data System (ADS)

McCartin, Joseph T.

1989-06-01

An analysis is presented for the throughput characteristics for several classes of Aloha packet networks. Specifically, the throughput for variable packet length Aloha utilizing multiple power levels to induce receiver capture is derived. The results are extended to an analysis of a selective-repeat ARQ Aloha network. Analytical results are presented which indicate a significant increase in throughput for a variable packet network implementing a random two power level capture scheme. Further research into the area of the near/far effect on Aloha networks is included. Improvements in throughput for mobile radio Aloha networks which are subject to the near/far effect are presented. Tactical Command, Control and Communications (C3) systems of the future will rely on Aloha ground mobile data networks. The incorporation of power capture and the near/far effect into future tactical networks will result in improved system analysis, design, and performance.

Network operability of ground-based microwave radiometers: Calibration and standardization efforts

NASA Astrophysics Data System (ADS)

Pospichal, Bernhard; Löhnert, Ulrich; Küchler, Nils; Czekala, Harald

2017-04-01

Ground-based microwave radiometers (MWR) are already widely used by national weather services and research institutions all around the world. Most of the instruments operate continuously and are beginning to be implemented into data assimilation for atmospheric models. Especially their potential for continuously observing boundary-layer temperature profiles as well as integrated water vapor and cloud liquid water path makes them valuable for improving short-term weather forecasts. However until now, most MWR have been operated as stand-alone instruments. In order to benefit from a network of these instruments, standardization of calibration, operation and data format is necessary. In the frame of TOPROF (COST Action ES1303) several efforts have been undertaken, such as uncertainty and bias assessment, or calibration intercomparison campaigns. The goal was to establish protocols for providing quality controlled (QC) MWR data and their uncertainties. To this end, standardized calibration procedures for MWR have been developed and recommendations for radiometer users compiled. Based on the results of the TOPROF campaigns, a new, high-accuracy liquid-nitrogen calibration load has been introduced for MWR manufactured by Radiometer Physics GmbH (RPG). The new load improves the accuracy of the measurements considerably and will lead to even more reliable atmospheric observations. Next to the recommendations for set-up, calibration and operation of ground-based MWR within a future network, we will present homogenized methods to determine the accuracy of a running calibration as well as means for automatic data quality control. This sets the stage for the planned microwave calibration center at JOYCE (Jülich Observatory for Cloud Evolution), which will be shortly introduced.

Regional and local networks of horizontal control, Cerro Prieto geothermal area

USGS Publications Warehouse

Massey, B.L.

1979-01-01

The Cerro Prieto geothermal area in the Mexicali Valley 30 km southeast of Mexicali, Baja California, is probably deforming due to (1) the extraction of large volumes of steam and hot water, and (2) active tectonism. Two networks of precise horizontal control were established in Mexicali Valley by the U.S. Geological Survey in 1977 - 1978 to measure both types of movement as they occur. These networks consisted of (1) a regional trilateration net brought into the mountain ranges west of the geothermal area from survey stations on an existing U.S. Geological Survey crustal-strain network north of the international border, and (2) a local net tied to stations in the regional net and encompassing the area of present and planned geothermal production. Survey lines in this net were selected to span areas of probable ground-surface movements in and around the geothermal area. Electronic distance measuring (EDM) instruments, operating with a modulated laser beam, were used to measure the distances between stations in both networks. The regional net was run using a highly precise long-range EDM instrument, helicopters for transportation of men and equipment to inaccessible stations on mountain peaks, and a fixed wing airplane flying along the line of sight. Precision of measurements with this complex long-range system approached 0-2 ppm of line length. The local net was measured with a medium-range EDM instrument requiring minimal ancillary equipment. Precision of measurements with this less complex system approached 3 ppm for the shorter line lengths. The detection and analysis of ground-surface movements resulting from tectonic strains or induced by geothermal fluid withdrawal is dependent on subsequent resurveys of these networks. ?? 1979.

Command and Control of Space Assets Through Internet-Based Technologies Demonstrated

NASA Technical Reports Server (NTRS)

Foltz, David A.

2002-01-01

The NASA Glenn Research Center successfully demonstrated a transmission-control-protocol/ Internet-protocol- (TCP/IP) based approach to the command and control of onorbit assets over a secure network. This is a significant accomplishment because future NASA missions will benefit by using Internet-standards-based protocols. Benefits of this Internet-based space command and control system architecture include reduced mission costs and increased mission efficiency. The demonstration proved that this communications architecture is viable for future NASA missions. This demonstration was a significant feat involving multiple NASA organizations and industry. Phillip Paulsen, from Glenn's Project Development and Integration Office, served as the overall project lead, and David Foltz, from Glenn's Satellite Networks and Architectures Branch, provided the hybrid networking support for the required Internet connections. The goal was to build a network that would emulate a connection between a space experiment on the International Space Station and a researcher accessing the experiment from anywhere on the Internet, as shown. The experiment was interfaced to a wireless 802.11 network inside the demonstration area. The wireless link provided connectivity to the Tracking and Data Relay Satellite System (TDRSS) Internet Link Terminal (TILT) satellite uplink terminal located 300 ft away in a parking lot on top of a panel van. TILT provided a crucial link in this demonstration. Leslie Ambrose, NASA Goddard Space Flight Center, provided the TILT/TDRSS support. The TILT unit transmitted the signal to TDRS 6 and was received at the White Sands Second TDRSS Ground Station. This station provided the gateway to the Internet. Coordination also took place at the White Sands station to install a Veridian Firewall and automated security incident measurement (ASIM) system to the Second TDRSS Ground Station Internet gateway. The firewall provides a trusted network for the simulated space experiment. A second Internet connection at the demonstration area was implemented to provide Internet connectivity to a group of workstations to serve as platforms for controlling the simulated space experiment. Installation of this Internet connection was coordinated with an Internet service provider (ISP) and local NASA Johnson Space Center personnel. Not only did this TCP/IP-based architecture prove that a principal investigator on the Internet can securely command and control on-orbit assets, it also demonstrated that valuable virtual testing of planned on-orbit activities can be conducted over the Internet prior to actual deployment in space.

A Ground Systems Architecture Transition for a Distributed Operations System

NASA Technical Reports Server (NTRS)

Sellers, Donna; Pitts, Lee; Bryant, Barry

2003-01-01

The Marshall Space Flight Center (MSFC) Ground Systems Department (GSD) recently undertook an architecture change in the product line that serves the ISS program. As a result, the architecture tradeoffs between data system product lines that serve remote users versus those that serve control center flight control teams were explored extensively. This paper describes the resulting architecture that will be used in the International Space Station (ISS) payloads program, and the resulting functional breakdown of the products that support this architecture. It also describes the lessons learned from the path that was followed, as a migration of products cause the need to reevaluate the allocation of functions across the architecture. The result is a set of innovative ground system solutions that is scalable so it can support facilities of wide-ranging sizes, from a small site up to large control centers. Effective use of system automation, custom components, design optimization for data management, data storage, data transmissions, and advanced local and wide area networking architectures, plus the effective use of Commercial-Off-The-Shelf (COTS) products, provides flexible Remote Ground System options that can be tailored to the needs of each user. This paper offers a description of the efficiency and effectiveness of the Ground Systems architectural options that have been implemented, and includes successful implementation examples and lessons learned.

Data Gathering and Energy Transfer Dilemma in UAV-Assisted Flying Access Network for IoT

PubMed Central

Arabi, Sara; Sadik, Mohamed

2018-01-01

Recently, Unmanned Aerial Vehicles (UAVs) have emerged as an alternative solution to assist wireless networks, thanks to numerous advantages they offer in comparison to terrestrial fixed base stations. For instance, a UAV can be used to embed a flying base station providing an on-demand nomadic access to network services. A UAV can also be used to wirelessly recharge out-of-battery ground devices. In this paper, we aim to deal with both data collection and recharging depleted ground Internet-of-Things (IoT) devices through a UAV station used as a flying base station. To extend the network lifetime, we present a novel use of UAV with energy harvesting module and wireless recharging capabilities. However, the UAV is used as an energy source to empower depleted IoT devices. On one hand, the UAV charges depleted ground IoT devices under three policies: (1) low-battery first scheme; (2) high-battery first scheme; and (3) random scheme. On the other hand, the UAV station collects data from IoT devices that have sufficient energy to transmit their packets, and in the same phase, the UAV exploits the Radio Frequency (RF) signals transmitted by IoT devices to extract and harvest energy. Furthermore, and as the UAV station has a limited coverage time due to its energy constraints, we propose and investigate an efficient trade-off between ground users recharging time and data gathering time. Furthermore, we suggest to control and optimize the UAV trajectory in order to complete its travel within a minimum time, while minimizing the energy spent and/or enhancing the network lifetime. Extensive numerical results and simulations show how the system behaves under different scenarios and using various metrics in which we examine the added value of UAV with energy harvesting module. PMID:29751662

Advanced ISDN satellite designs and experiments

NASA Technical Reports Server (NTRS)

Pepin, Gerard R.

1992-01-01

The research performed by GTE Government Systems and the University of Colorado in support of the NASA Satellite Communications Applications Research (SCAR) Program is summarized. Two levels of research were undertaken. The first dealt with providing interim services Integrated Services Digital Network (ISDN) satellite (ISIS) capabilities that accented basic rate ISDN with a ground control similar to that of the Advanced Communications Technology Satellite (ACTS). The ISIS Network Model development represents satellite systems like the ACTS orbiting switch. The ultimate aim is to move these ACTS ground control functions on-board the next generation of ISDN communications satellite to provide full-service ISDN satellite (FSIS) capabilities. The technical and operational parameters for the advanced ISDN communications satellite design are obtainable from the simulation of ISIS and FSIS engineering software models of the major subsystems of the ISDN communications satellite architecture. Discrete event simulation experiments would generate data for analysis against NASA SCAR performance measure and the data obtained from the ISDN satellite terminal adapter hardware (ISTA) experiments, also developed in the program. The Basic and Option 1 phases of the program are also described and include the following: literature search, traffic mode, network model, scenario specifications, performance measures definitions, hardware experiment design, hardware experiment development, simulator design, and simulator development.

TCP Performance Enhancement Over Iridium

NASA Technical Reports Server (NTRS)

Torgerson, Leigh; Hutcherson, Joseph; McKelvey, James

2007-01-01

In support of iNET maturation, NASA-JPL has collaborated with NASA-Dryden to develop, test and demonstrate an over-the-horizon vehicle-to-ground networking capability, using Iridium as the vehicle-to-ground communications link for relaying critical vehicle telemetry. To ensure reliability concerns are met, the Space Communications Protocol Standards (SCPS) transport protocol was investigated for its performance characteristics in this environment. In particular, the SCPS-TP software performance was compared to that of the standard Transmission Control Protocol (TCP) over the Internet Protocol (IP). This paper will report on the results of this work.

Cognitive and Social Structure of the Elite Collaboration Network of Astrophysics: A Case Study on Shifting Network Structures

ERIC Educational Resources Information Center

Heidler, Richard

2011-01-01

Scientific collaboration can only be understood along the epistemic and cognitive grounding of scientific disciplines. New scientific discoveries in astrophysics led to a major restructuring of the elite network of astrophysics. To study the interplay of the epistemic grounding and the social network structure of a discipline, a mixed-methods…

Georgia's Ground-Water Resources and Monitoring Network, 2006

USGS Publications Warehouse

Nobles, Patricia L.

2006-01-01

The U.S. Geological Survey (USGS) ground-water network for Georgia currently consists of 170 wells in which ground-water levels are continuously monitored. Most of the wells are locatedin the Coastal Plain in the southern part of the State where ground-water pumping stress is high. In particular, there are large concentrations of wells in coastal and southwestern Georgia areas, where there are issues related to ground-water pumping, saltwater intrusion along the coast, and diminished streamflow in southwestern Georgia due to irrigation pumping. The map at right shows the USGS ground-water monitoring network for Georgia. Ground-water levels are monitored in 170 wells statewide, of which 19 transmit data in real time via satellite and posted on the World Wide Web at http://waterdata.usgs.gov/ga/nwis/current/?type=gw . A greater concentration of wells occurs in the Coastal Plain where there are several layers of aquifers and in coastal and southwestern Georgia areas, which are areas with specific ground-water issues.

Time Synchronization Prototype, Server Upgrade Procedure Support and Remote Software Development

NASA Technical Reports Server (NTRS)

Sanders, Shania R.

2014-01-01

Networks are roadways of communication that connect devices. Like all roadways, there are rules and regulations that govern whatever (information in this case) travels along them. One type of rule that is commonly used is called a protocol. More specifically, a protocol is a standard that specifies how data should be transmitted over a network. The project outlined in this document seeks to implement one protocol in particular, Precision Time Protocol, within the Kennedy Ground Control Subsystem network at Kennedy Space Center. This document also summarizes work completed for server upgrades, remote software developer training and how all three assignments demonstrated the importance of accountability and security.

Optimizing digital elevation models (DEMs) accuracy for planning and design of mobile communication networks

NASA Astrophysics Data System (ADS)

Hassan, Mahmoud A.

2004-02-01

Digital elevation models (DEMs) are important tools in the planning, design and maintenance of mobile communication networks. This research paper proposes a method for generating high accuracy DEMs based on SPOT satellite 1A stereo pair images, ground control points (GCP) and Erdas OrthoBASE Pro image processing software. DEMs with 0.2911 m mean error were achieved for the hilly and heavily populated city of Amman. The generated DEM was used to design a mobile communication network resulted in a minimum number of radio base transceiver stations, maximum number of covered regions and less than 2% of dead zones.

Unmanned Ground Vehicle Navigation and Coverage Hole Patching in Wireless Sensor Networks

ERIC Educational Resources Information Center

Zhang, Guyu

2013-01-01

This dissertation presents a study of an Unmanned Ground Vehicle (UGV) navigation and coverage hole patching in coordinate-free and localization-free Wireless Sensor Networks (WSNs). Navigation and coverage maintenance are related problems since coverage hole patching requires effective navigation in the sensor network environment. A…

Attentional impairments in Huntington's disease: A specific deficit for the executive conflict.

PubMed

Maurage, Pierre; Heeren, Alexandre; Lahaye, Magali; Jeanjean, Anne; Guettat, Lamia; Verellen-Dumoulin, Christine; Halkin, Stéphane; Billieux, Joël; Constant, Eric

2017-05-01

Huntington's disease (HD) is characterized by motor and cognitive impairments including memory, executive, and attentional functions. However, because earlier studies relied on multidetermined attentional tasks, uncertainty still abounds regarding the differential deficit across attentional subcomponents. Likewise, the evolution of these deficits during the successive stages of HD remains unclear. The present study simultaneously explored 3 distinct networks of attention (alerting, orienting, executive conflict) in preclinical and clinical HD. Thirty-eight HD patients (18 preclinical) and 38 matched healthy controls completed the attention network test, an integrated and theoretically grounded task assessing the integrity of 3 attentional networks. Preclinical HD was not characterized by any attentional deficit compared to controls. Conversely, clinical HD was associated with a differential deficit across the 3 attentional networks under investigation, showing preserved performance for alerting and orienting networks but massive and specific impairment for the executive conflict network. This indexes an impaired use of executive control to resolve the conflict between task-relevant stimuli and interfering task-irrelevant ones. Clinical HD does not lead to a global attentional deficit but rather to a specific impairment for the executive control of attention. Moreover, the absence of attentional deficits in preclinical HD suggests that these deficits are absent at the initial stages of the disease. In view of their impact on everyday life, attentional deficits should be considered in clinical contexts. Therapeutic programs improving the executive control of attention by neuropsychology and neuromodulation should be promoted. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Definition, analysis and development of an optical data distribution network for integrated avionics and control systems. Part 2: Component development and system integration

NASA Technical Reports Server (NTRS)

Yen, H. W.; Morrison, R. J.

1984-01-01

Fiber optic transmission is emerging as an attractive concept in data distribution onboard civil aircraft. Development of an Optical Data Distribution Network for Integrated Avionics and Control Systems for commercial aircraft will provide a data distribution network that gives freedom from EMI-RFI and ground loop problems, eliminates crosstalk and short circuits, provides protection and immunity from lightning induced transients and give a large bandwidth data transmission capability. In addition there is a potential for significantly reducing the weight and increasing the reliability over conventional data distribution networks. Wavelength Division Multiplexing (WDM) is a candidate method for data communication between the various avionic subsystems. With WDM all systems could conceptually communicate with each other without time sharing and requiring complicated coding schemes for each computer and subsystem to recognize a message. However, the state of the art of optical technology limits the application of fiber optics in advanced integrated avionics and control systems. Therefore, it is necessary to address the architecture for a fiber optics data distribution system for integrated avionics and control systems as well as develop prototype components and systems.

Supervisory control of mobile sensor networks: math formulation, simulation, and implementation.

PubMed

Giordano, Vincenzo; Ballal, Prasanna; Lewis, Frank; Turchiano, Biagio; Zhang, Jing Bing

2006-08-01

This paper uses a novel discrete-event controller (DEC) for the coordination of cooperating heterogeneous wireless sensor networks (WSNs) containing both unattended ground sensors (UGSs) and mobile sensor robots. The DEC sequences the most suitable tasks for each agent and assigns sensor resources according to the current perception of the environment. A matrix formulation makes this DEC particularly useful for WSN, where missions change and sensor agents may be added or may fail. WSN have peculiarities that complicate their supervisory control. Therefore, this paper introduces several new tools for DEC design and operation, including methods for generating the required supervisory matrices based on mission planning, methods for modifying the matrices in the event of failed nodes, or nodes entering the network, and a novel dynamic priority assignment weighting approach for selecting the most appropriate and useful sensors for a given mission task. The resulting DEC represents a complete dynamical description of the WSN system, which allows a fast programming of deployable WSN, a computer simulation analysis, and an efficient implementation. The DEC is actually implemented on an experimental wireless-sensor-network prototyping system. Both simulation and experimental results are presented to show the effectiveness and versatility of the developed control architecture.

DEVELOPMENT OF QUALITY ASSURANCE AND QUALITY CONTROL GUIDANCE FOR GROUND-BASED REMOTE SENSORS FOR USE IN REGULATORY MONITORING

EPA Science Inventory

The U.S. Environmental Protection Agency's (EPA) authority for enhanced monitoring activities is provided for in Title I, Section 182 of the Clean Air Act Amendment of 1990. or example, the Photochemical Assessment Monitoring Station (PAMS) network is one such program which requi...

Genome-Wide Expression Analysis of Reactive Oxygen Species Gene Network in Mizuna Plants Grown in Long-Term Spaceflight

NASA Astrophysics Data System (ADS)

Sugimoto, Manabu; Gusev, Oleg; Wheeler, Raymond; Levinskikh, Margarita; Sychev, Vladimir; Bingham, Gail; Hummerick, Mary; Oono, Youko; Matsumoto, Takashi; Yazawa, Takayuki

We have developed a plant growth system, namely Lada, which was installed in ISS to study and grow plants, including vegetables in a spaceflight environment. We have succeeded in cultivating Mizuna, tomato, pea, radish, wheat, rice, and barley in long-term spaceflight. Transcription levels of superoxide dismutase, glutamyl transferase, catalase, and ascorbate peroxidase were increased in the barley germinated and grown for 26 days in Lada, though the whole-plant growth and development of the barley in spaceflight were the same as in the ground control barley. In this study, we investigated the response of the ROS gene network in Mizuna, Brassica rapa var. nipposinica, cultivated under spaceflight condition. Seeds of Mizuna were sown in the root module of LADA aboard the Zvezda module of ISS and the seedlings were grown under 24h lighting in the leaf chamber. After 27 days of cultivation, the plants were harvested and stored at -80(°) C in MELFI aboard the Destiny module, and were transported to the ground at < -20(°) C in GLACIER aboard Space Shuttle. Ground control cultivation was carried out under the same conditions in LADA. Total RNA isolated from leaves was subjected to mRNA-Seq using next generation sequencing (NGS) technology. A total of 20 in 32 ROS oxidative marker genes were up-regulated, including high expression of four hallmarks, and preferentially expressed genes associated with ROS-scavenging including thioredoxin, glutaredoxin, and alternative oxidase genes. In the transcription factors of the ROS gene network, MEKK1-MKK4-MPK3, OXI1-MKK4-MPK3, and OXI1-MPK3 of MAP cascades, induction of WRKY22 by MEKK1-MKK4-MPK3 cascade, induction of WRKY25 and repression of Zat7 by Zat12 were suggested. These results revealed that the spaceflight environment induced oxidative stress and the ROS gene network activation in the space-grown Mizuna.

Adaptive Neural Network Algorithm for Power Control in Nuclear Power Plants

NASA Astrophysics Data System (ADS)

Masri Husam Fayiz, Al

2017-01-01

The aim of this paper is to design, test and evaluate a prototype of an adaptive neural network algorithm for the power controlling system of a nuclear power plant. The task of power control in nuclear reactors is one of the fundamental tasks in this field. Therefore, researches are constantly conducted to ameliorate the power reactor control process. Currently, in the Department of Automation in the National Research Nuclear University (NRNU) MEPhI, numerous studies are utilizing various methodologies of artificial intelligence (expert systems, neural networks, fuzzy systems and genetic algorithms) to enhance the performance, safety, efficiency and reliability of nuclear power plants. In particular, a study of an adaptive artificial intelligent power regulator in the control systems of nuclear power reactors is being undertaken to enhance performance and to minimize the output error of the Automatic Power Controller (APC) on the grounds of a multifunctional computer analyzer (simulator) of the Water-Water Energetic Reactor known as Vodo-Vodyanoi Energetichesky Reaktor (VVER) in Russian. In this paper, a block diagram of an adaptive reactor power controller was built on the basis of an intelligent control algorithm. When implementing intelligent neural network principles, it is possible to improve the quality and dynamic of any control system in accordance with the principles of adaptive control. It is common knowledge that an adaptive control system permits adjusting the controller’s parameters according to the transitions in the characteristics of the control object or external disturbances. In this project, it is demonstrated that the propitious options for an automatic power controller in nuclear power plants is a control system constructed on intelligent neural network algorithms.

Obstacle negotiation control for a mobile robot suspended on overhead ground wires by optoelectronic sensors

NASA Astrophysics Data System (ADS)

Zheng, Li; Yi, Ruan

2009-11-01

Power line inspection and maintenance already benefit from developments in mobile robotics. This paper presents mobile robots capable of crossing obstacles on overhead ground wires. A teleoperated robot realizes inspection and maintenance tasks on power transmission line equipment. The inspection robot is driven by 11 motor with two arms, two wheels and two claws. The inspection robot is designed to realize the function of observation, grasp, walk, rolling, turn, rise, and decline. This paper is oriented toward 100% reliable obstacle detection and identification, and sensor fusion to increase the autonomy level. An embedded computer based on PC/104 bus is chosen as the core of control system. Visible light camera and thermal infrared Camera are both installed in a programmable pan-and-tilt camera (PPTC) unit. High-quality visual feedback rapidly becomes crucial for human-in-the-loop control and effective teleoperation. The communication system between the robot and the ground station is based on Mesh wireless networks by 700 MHz bands. An expert system programmed with Visual C++ is developed to implement the automatic control. Optoelectronic laser sensors and laser range scanner were installed in robot for obstacle-navigation control to grasp the overhead ground wires. A novel prototype with careful considerations on mobility was designed to inspect the 500KV power transmission lines. Results of experiments demonstrate that the robot can be applied to execute the navigation and inspection tasks.

Moball-Buoy Network: A Near-Real-Time Ground-Truth Distributed Monitoring System to Map Ice, Weather, Chemical Species, and Radiations, in the Arctic

NASA Astrophysics Data System (ADS)

Davoodi, F.; Shahabi, C.; Burdick, J.; Rais-Zadeh, M.; Menemenlis, D.

2014-12-01

The work had been funded by NASA HQ's office of Cryospheric Sciences Program. Recent observations of the Arctic have shown that sea ice has diminished drastically, consequently impacting the environment in the Arctic and beyond. Certain factors such as atmospheric anomalies, wind forces, temperature increase, and change in the distribution of cold and warm waters contribute to the sea ice reduction. However current measurement capabilities lack the accuracy, temporal sampling, and spatial coverage required to effectively quantify each contributing factor and to identify other missing factors. Addressing the need for new measurement capabilities for the new Arctic regime, we propose a game-changing in-situ Arctic-wide Distributed Mobile Monitoring system called Moball-buoy Network. Moball-buoy Network consists of a number of wind-propelled self-powered inflatable spheres referred to as Moball-buoys. The Moball-buoys are self-powered. They use their novel mechanical control and energy harvesting system to use the abundance of wind in the Arctic for their controlled mobility and energy harvesting. They are equipped with an array of low-power low-mass sensors and micro devices able to measure a wide range of environmental factors such as the ice conditions, chemical species wind vector patterns, cloud coverage, air temperature and pressure, electromagnetic fields, surface and subsurface water conditions, short- and long-wave radiations, bathymetry, and anthropogenic factors such as pollutions. The stop-and-go motion capability, using their novel mechanics, and the heads up cooperation control strategy at the core of the proposed distributed system enable the sensor network to be reconfigured dynamically according to the priority of the parameters to be monitored. The large number of Moball-buoys with their ground-based, sea-based, satellite and peer-to-peer communication capabilities would constitute a wireless mesh network that provides an interface for a global control system. This control system will ensure arctic-wide coverage, will optimize Moball-buoys monitoring efforts according to their available resources and the priority of local areas of high scientific value within the Arctic region. Moball-buoy Network is expected to be the first robust and persistent Arctic-wide environment monitoring system capable of providing reliable readings in near real time

Aeronautics and Space Report of the President: Fiscal Year 1996 Activities

NASA Technical Reports Server (NTRS)

1996-01-01

Topics considered include: (1) Space launch activities: space shuttle missions; expendable launch vehicles. (2) Space science: astronomy and space physics; solar system exploration. (3) Space flight and technology: life and microgravity sciences; space shuttle technology; reuseable launch vehicles; international space station; energy; safety and mission assurance; commercial development and regulation of space; surveillance. (4) Space communications: communications satellites; space network; ground networks; mission control and data systems. (5) Aeronautical activities: technology developments; air traffic control and navigation; weather-related aeronautical activities; flight safety and security; aviation medicine and human factors. (6) Studies of the planet earth: terrestrial studies and applications: atmospheric studies: oceanographic studies; international aeronautical and space activities; and appendices.

Datum maintenance of the main Egyptian geodetic control networks by utilizing Precise Point Positioning "PPP" technique

NASA Astrophysics Data System (ADS)

Rabah, Mostafa; Elmewafey, Mahmoud; Farahan, Magda H.

2016-06-01

A geodetic control network is the wire-frame or the skeleton on which continuous and consistent mapping, Geographic Information Systems (GIS), and surveys are based. Traditionally, geodetic control points are established as permanent physical monuments placed in the ground and precisely marked, located, and documented. With the development of satellite surveying methods and their availability and high degree of accuracy, a geodetic control network could be established by using GNSS and referred to an international terrestrial reference frame used as a three-dimensional geocentric reference system for a country. Based on this concept, in 1992, the Egypt Survey Authority (ESA) established two networks, namely High Accuracy Reference Network (HARN) and the National Agricultural Cadastral Network (NACN). To transfer the International Terrestrial Reference Frame to the HARN, the HARN was connected with four IGS stations. The processing results were 1:10,000,000 (Order A) for HARN and 1:1,000,000 (Order B) for NACN relative network accuracy standard between stations defined in ITRF1994 Epoch1996. Since 1996, ESA did not perform any updating or maintaining works for these networks. To see how non-performing maintenance degrading the values of the HARN and NACN, the available HARN and NACN stations in the Nile Delta were observed. The Processing of the tested part was done by CSRS-PPP Service based on utilizing Precise Point Positioning "PPP" and Trimble Business Center "TBC". The study shows the feasibility of Precise Point Positioning in updating the absolute positioning of the HARN network and its role in updating the reference frame (ITRF). The study also confirmed the necessity of the absent role of datum maintenance of Egypt networks.

Designed to Win: An Agile Approach to Air Force Command and Control of Cyberspace

DTIC Science & Technology

2010-06-01

capabilities and limitations of technology with a level of control that synchronizes operations, yet allows independent action to take advantage of...was during the Roman Empire. With the exception of the semaphore telegraph and an improved road network, the same methods of communication used by...48 To provide information quickly to the ground commanders, the Aviation Section of the US Signal Corps installed primitive wireless radio sets in

ITC/USA/'90; Proceedings of the International Telemetering Conference, Las Vegas, NV, Oct. 29-Nov. 2, 1990

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1990-01-01

This conference presents papers in the fields of airborne telemetry, measurement technology, video instrumentation and monitoring, tracking and receiving systems, and real-time processing in telemetry. Topics presented include packet telemetry ground station simulation, a predictable performance wideband noise generator, an improved drone tracking control system transponder, the application of neural networks to drone control, and an integrated real-time turbine engine flight test system.

A flexible CAMAC based data system for Space Shuttle scientific instruments

NASA Technical Reports Server (NTRS)

Ehrmann, C. H.; Baker, R. G.; Smith, R. L.; Kaminski, T. J.

1979-01-01

An effort has been made within NASA to produce a low-cost modular system for implementation of Shuttle payloads based on the CAMAC standards for packaging and data transfer. A key element of such a modular system is a means for controlling the data system, collecting and processing the data for transmission to the ground, and issuing commands to the instrument either from the ground or based on the data collected. A description is presented of such a means based on a network of digital processors and CAMAC crate controllers, which allows for the implementation of instruments ranging from those requiring only a single CAMAC crate of functional modules and no data processing to ones requiring multiple crates and multiple data processors.

Monitoring Fine-Grained Sediment in the Colorado River Ecosystem, Arizona - Control Network and Conventional Survey Techniques

USGS Publications Warehouse

Hazel, Joseph E.; Kaplinski, Matt; Parnell, Roderic A.; Kohl, Keith; Schmidt, John C.

2008-01-01

In 2002, fine-grained sediment (sand, silt, and clay) monitoring in the Colorado River downstream from Glen Canyon Dam was initiated to survey channel topography at scales previously unobtainable in this canyon setting. This report presents the methods used to establish the high-resolution global positioning system (GPS) control network required for this effort as well as the conventional surveying techniques used in the study. Using simultaneous, dual-frequency GPS vector-based methods, the network points were determined to have positioning accuracies of less than 0.03 meters (m) and ellipsoidal height accuracies of between 0.01 and 0.10 m at a 95-percent degree of confidence. We also assessed network point quality with repeated, electronic (optical) total-station observations at 39 points for a total of 362 measurements; the mean range was 0.022 m in horizontal and 0.13 in vertical at a 95-percent confidence interval. These results indicate that the control network is of sufficient spatial and vertical accuracy for collection of airborne and subaerial remote-sensing technologies and integration of these data in a geographic information system on a repeatable basis without anomalies. The monitoring methods were employed in up to 11 discrete reaches over various time intervals. The reaches varied from 1.3 to 6.4 kilometers in length. Field results from surveys in 2000, 2002, and 2004 are described, during which conventional surveying was used to collect more than 3000 points per day. Ground points were used as checkpoints and to supplement areas just below or above the water surface, where remote-sensing data are not collected or are subject to greater error. An accuracy of +or- 0.05 m was identified as the minimum precision of individual ground points. These results are important for assessing digital elevation model (DEM) quality and identifying detection limits of significant change among surfaces generated from remote-sensing technologies.

Evaluation of the U.S. Geological Survey Ground-Water Data-Collection Program in Hawaii, 1992

USGS Publications Warehouse

Anthony, Stephen S.

1997-01-01

In 1992, the U.S. Geological Survey ground-water data-collection program in the State of Hawaii consisted of 188 wells distributed among the islands of Oahu, Kauai, Maui, Molokai, and Hawaii. Water-level and water-quality (temperature, specific conductance, and chloride concentration) data were collected from observation wells, deep monitoring wells that penetrate the zone of transition between freshwater and saltwater, free-flowing wells, and pumped wells. The objective of the program was to collect sufficient spatial and temporal data to define seasonal and long-term changes in ground-water levels and chloride concentrations induced by natural and human-made stresses for different climatic and hydrogeologic settings. Wells needed to meet this objective can be divided into two types of networks: (1) a water-management network to determine the response of ground-water flow systems to human-induced stresses, such as pumpage, and (2) a baseline network to determine the response of ground-water flow systems to natural stresses for different climatic and hydrogeologic settings. Maps showing the distribution and magnitude of pumpage and the distribution of proposed pumped wells are presented to identify areas in need of water-management networks. Wells in the 1992 U.S. Geological Survey ground-water data-collection program were classified as either water-management or baseline network wells. In addition, locations where additional water-management network wells are needed for water-level and water-quality data were identified.

Walking or Waiting? Topologies of the Breeding Ground in Malaria Control

PubMed Central

Lezaun, Javier

2013-01-01

Few places bear as much historical and scientific significance as the breeding ground, the accumulation of stagnant water where disease-carrying insects lay their eggs. Since the turn of the twentieth century, when mosquitoes of the Anopheles genus were identified as the vector of malaria transmission, these aquatic habitats have been a key object of epidemiological research and public health intervention against the disease. Yet the breeding ground can be incorporated into a number of different topologies, each implying a different spatialization of malaria and a distinct imagination of what kind of mosquito control is ‘doable'. A contemporary example of malaria control in Dar es Salaam, Tanzania, illuminates an essential tension between what we characterize as territorial and bionomic approaches to the breeding ground—that is, between control strategies premised on treating all mosquito habitats within a given region, and those that prioritize certain sites on the basis of their position within ecological networks. Each topology localizes the breeding ground by reference to a distinct set of relations, and thus advances an idiosyncratic understanding of what sort of research is worthwhile conducting and what kinds of intervention are sustainable. The multiple ways in which the breeding ground can become an object of research and action clarifies the role of topology as an infra-logic of public health, and makes explicit the politics implicit in efforts to bring different orders of the local to scale. PMID:25937707

The public health response to the re-emergence of syphilis in Wales, UK.

PubMed

Thomas, D Rh; Cann, K F; Evans, M R; Roderick, J; Browning, M; Birley, H D L; Curley, W; Clark, P; Northey, G; Caple, S; Lyons, M

2011-09-01

During the 1990s, cases of infectious syphilis were uncommon in Wales. In 2002, an outbreak occurred in a sexual network of men who have sex with men (MSM) attending a sauna. A multidisciplinary outbreak control team was convened to raise awareness of the outbreak among MSM and health professionals, assess the extent of outbreak, and initiate surveillance measures. It is likely that early intensive control efforts dampened the epidemic curve. However, since 2006 the number of cases has increased steadily to a peak of four cases per 100,000 population in 2008. The majority of cases continue to occur in MSM (81% in 2009) and in those attending genitourinary (GU) medicine clinics in south east Wales (76%). Traditional sexual networks such as saunas, bars/clubs and cruising grounds remain frequently reported, but Internet-based networks are assuming increasing importance. Public health interventions have been sustained, using traditional partner notification, health promotion initiatives, and more innovative Internet network tracing methods.

Ad Hoc Networking for Unmanned Ground Vehicles: Design and Evaluation at Command, Control, Communications, Intelligence, Surveillance and Reconnaissance On-the-Move

DTIC Science & Technology

2006-11-01

software components used in the ad hoc nodes for the C4ISR OTM experiment were OLSRD, an open-source proactive MANET routing software, and OpenVPN , an...developed by Mike Baker (openwrt.org). 6OpenVPN is a trademark of OpenVPN Solutions LLC. 6 Secure communications in the MANET are achieved with...encryption provided by Wired Equivalent Privacy (WEP) and OpenVPN . The WEP protocol, which is part of the IEEE 802.11 wireless networking standard

Optimized autonomous space in-situ sensor web for volcano monitoring

USGS Publications Warehouse

Song, W.-Z.; Shirazi, B.; Huang, R.; Xu, M.; Peterson, N.; LaHusen, R.; Pallister, J.; Dzurisin, D.; Moran, S.; Lisowski, M.; Kedar, S.; Chien, S.; Webb, F.; Kiely, A.; Doubleday, J.; Davies, A.; Pieri, D.

2010-01-01

In response to NASA's announced requirement for Earth hazard monitoring sensor-web technology, a multidisciplinary team involving sensor-network experts (Washington State University), space scientists (JPL), and Earth scientists (USGS Cascade Volcano Observatory (CVO)), have developed a prototype of dynamic and scalable hazard monitoring sensor-web and applied it to volcano monitoring. The combined Optimized Autonomous Space In-situ Sensor-web (OASIS) has two-way communication capability between ground and space assets, uses both space and ground data for optimal allocation of limited bandwidth resources on the ground, and uses smart management of competing demands for limited space assets. It also enables scalability and seamless infusion of future space and in-situ assets into the sensor-web. The space and in-situ control components of the system are integrated such that each element is capable of autonomously tasking the other. The ground in-situ was deployed into the craters and around the flanks of Mount St. Helens in July 2009, and linked to the command and control of the Earth Observing One (EO-1) satellite. ?? 2010 IEEE.

Regulation of Dynamical Systems to Optimal Solutions of Semidefinite Programs: Algorithms and Applications to AC Optimal Power Flow

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dall'Anese, Emiliano; Dhople, Sairaj V.; Giannakis, Georgios B.

2015-07-01

This paper considers a collection of networked nonlinear dynamical systems, and addresses the synthesis of feedback controllers that seek optimal operating points corresponding to the solution of pertinent network-wide optimization problems. Particular emphasis is placed on the solution of semidefinite programs (SDPs). The design of the feedback controller is grounded on a dual e-subgradient approach, with the dual iterates utilized to dynamically update the dynamical-system reference signals. Global convergence is guaranteed for diminishing stepsize rules, even when the reference inputs are updated at a faster rate than the dynamical-system settling time. The application of the proposed framework to the controlmore » of power-electronic inverters in AC distribution systems is discussed. The objective is to bridge the time-scale separation between real-time inverter control and network-wide optimization. Optimization objectives assume the form of SDP relaxations of prototypical AC optimal power flow problems.« less

Flexible network wireless transceiver and flexible network telemetry transceiver

DOEpatents

Brown, Kenneth D.

2008-08-05

A transceiver for facilitating two-way wireless communication between a baseband application and other nodes in a wireless network, wherein the transceiver provides baseband communication networking and necessary configuration and control functions along with transmitter, receiver, and antenna functions to enable the wireless communication. More specifically, the transceiver provides a long-range wireless duplex communication node or channel between the baseband application, which is associated with a mobile or fixed space, air, water, or ground vehicle or other platform, and other nodes in the wireless network or grid. The transceiver broadly comprises a communication processor; a flexible telemetry transceiver including a receiver and a transmitter; a power conversion and regulation mechanism; a diplexer; and a phased array antenna system, wherein these various components and certain subcomponents thereof may be separately enclosed and distributable relative to the other components and subcomponents.

Topological data analysis of contagion maps for examining spreading processes on networks.

PubMed

Taylor, Dane; Klimm, Florian; Harrington, Heather A; Kramár, Miroslav; Mischaikow, Konstantin; Porter, Mason A; Mucha, Peter J

2015-07-21

Social and biological contagions are influenced by the spatial embeddedness of networks. Historically, many epidemics spread as a wave across part of the Earth's surface; however, in modern contagions long-range edges-for example, due to airline transportation or communication media-allow clusters of a contagion to appear in distant locations. Here we study the spread of contagions on networks through a methodology grounded in topological data analysis and nonlinear dimension reduction. We construct 'contagion maps' that use multiple contagions on a network to map the nodes as a point cloud. By analysing the topology, geometry and dimensionality of manifold structure in such point clouds, we reveal insights to aid in the modelling, forecast and control of spreading processes. Our approach highlights contagion maps also as a viable tool for inferring low-dimensional structure in networks.

Topological data analysis of contagion maps for examining spreading processes on networks

NASA Astrophysics Data System (ADS)

Taylor, Dane; Klimm, Florian; Harrington, Heather A.; Kramár, Miroslav; Mischaikow, Konstantin; Porter, Mason A.; Mucha, Peter J.

2015-07-01

Social and biological contagions are influenced by the spatial embeddedness of networks. Historically, many epidemics spread as a wave across part of the Earth's surface; however, in modern contagions long-range edges--for example, due to airline transportation or communication media--allow clusters of a contagion to appear in distant locations. Here we study the spread of contagions on networks through a methodology grounded in topological data analysis and nonlinear dimension reduction. We construct `contagion maps' that use multiple contagions on a network to map the nodes as a point cloud. By analysing the topology, geometry and dimensionality of manifold structure in such point clouds, we reveal insights to aid in the modelling, forecast and control of spreading processes. Our approach highlights contagion maps also as a viable tool for inferring low-dimensional structure in networks.

Proposed Development of NASA Glenn Research Center's Aeronautical Network Research Simulator

NASA Technical Reports Server (NTRS)

Nguyen, Thanh C.; Kerczewski, Robert J.; Wargo, Chris A.; Kocin, Michael J.; Garcia, Manuel L.

2004-01-01

Accurate knowledge and understanding of data link traffic loads that will have an impact on the underlying communications infrastructure within the National Airspace System (NAS) is of paramount importance for planning, development and fielding of future airborne and ground-based communications systems. Attempting to better understand this impact, NASA Glenn Research Center (GRC), through its contractor Computer Networks & Software, Inc. (CNS, Inc.), has developed an emulation and test facility known as the Virtual Aircraft and Controller (VAC) to study data link interactions and the capacity of the NAS to support Controller Pilot Data Link Communications (CPDLC) traffic. The drawback of the current VAC test bed is that it does not allow the test personnel and researchers to present a real world RF environment to a complex airborne or ground system. Fortunately, the United States Air Force and Navy Avionics Test Commands, through its contractor ViaSat, Inc., have developed the Joint Communications Simulator (JCS) to provide communications band test and simulation capability for the RF spectrum through 18 GHz including Communications, Navigation, and Identification and Surveillance functions. In this paper, we are proposing the development of a new and robust test bed that will leverage on the existing NASA GRC's VAC and the Air Force and Navy Commands JCS systems capabilities and functionalities. The proposed NASA Glenn Research Center's Aeronautical Networks Research Simulator (ANRS) will combine current Air Traffic Control applications and physical RF stimulation into an integrated system capable of emulating data transmission behaviors including propagation delay, physical protocol delay, transmission failure and channel interference. The ANRS will provide a simulation/stimulation tool and test bed environment that allow the researcher to predict the performance of various aeronautical network protocol standards and their associated waveforms under varying density conditions. The system allows the user to define human-interactive and scripted aircraft and controller models of various standards, such as (but not limited to) Very High Frequency Digital Link (VDL) of various modes.

An fMRI investigation of the relationship between future imagination and cognitive flexibility

PubMed Central

Roberts, R.P.; Wiebels, K.; Sumner, R.L.; van Mulukom, V.; Grady, C.L.; Schacter, D.L.; Addis, D.R.

2016-01-01

While future imagination is largely considered to be a cognitive process grounded in default mode network activity, studies have shown that future imagination recruits regions in both default mode and frontoparietal control networks. In addition, it has recently been shown that the ability to imagine the future is associated with cognitive flexibility, and that tasks requiring cognitive flexibility result in increased coupling of the default mode network with frontoparietal control and salience networks. In the current study, we investigated the neural correlates underlying the association between cognitive flexibility and future imagination in two ways. First, we experimentally varied the degree of cognitive flexibility required during future imagination by manipulating the disparateness of episodic details contributing to imagined events. To this end, participants generated episodic details (persons, locations, objects) within three social spheres; during fMRI scanning they were presented with sets of three episodic details all taken from the same social sphere (Congruent condition) or different social spheres (Incongruent condition) and required to imagine a future event involving the three details. We predicted that, relative to the Congruent condition, future simulation in the Incongruent condition would be associated with increased activity in regions of the default mode, frontoparietal and salience networks. Second, we hypothesized that individual differences in cognitive flexibility, as measured by performance on the Alternate Uses Task, would correspond to individual differences in the brain regions recruited during future imagination. A task partial least squares (PLS) analysis showed that the Incongruent condition resulted in an increase in activity in regions in salience networks (e.g. the insula) but, contrary to our prediction, reduced activity in many regions of the default mode network (including the hippocampus). A subsequent functional connectivity (within-subject seed PLS) analysis showed that the insula exhibited increased coupling with default mode regions during the Incongruent condition. Finally, a behavioral PLS analysis showed that individual differences in cognitive flexibility were associated with differences in activity in a number of regions from frontoparietal, salience and default-mode networks during both future imagination conditions, further highlighting that the cognitive flexibility underlying future imagination is grounded in the complex interaction of regions in these networks. PMID:27908591

A radiation-hardened, computer for satellite applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gaona, J.I. Jr.

1996-08-01

This paper describes high reliability radiation hardened computers built by Sandia for application aboard DOE satellite programs requiring 32 bit processing. The computers highlight a radiation hardened (10 kGy(Si)) R3000 executing up to 10 million reduced instruction set instructions (RISC) per second (MIPS), a dual purpose module control bus used for real-time default and power management which allows for extended mission operation on as little as 1.2 watts, and a local area network capable of 480 Mbits/s. The central processing unit (CPU) is the NASA Goddard R3000 nicknamed the ``Mongoose or Mongoose 1``. The Sandia Satellite Computer (SSC) uses Rational`smore » Ada compiler, debugger, operating system kernel, and enhanced floating point emulation library targeted at the Mongoose. The SSC gives Sandia the capability of processing complex types of spacecraft attitude determination and control algorithms and of modifying programmed control laws via ground command. And in general, SSC offers end users the ability to process data onboard the spacecraft that would normally have been sent to the ground which allows reconsideration of traditional space-grounded partitioning options.« less

Collective dynamics of 'small-world' networks.

PubMed

Watts, D J; Strogatz, S H

1998-06-04

Networks of coupled dynamical systems have been used to model biological oscillators, Josephson junction arrays, excitable media, neural networks, spatial games, genetic control networks and many other self-organizing systems. Ordinarily, the connection topology is assumed to be either completely regular or completely random. But many biological, technological and social networks lie somewhere between these two extremes. Here we explore simple models of networks that can be tuned through this middle ground: regular networks 'rewired' to introduce increasing amounts of disorder. We find that these systems can be highly clustered, like regular lattices, yet have small characteristic path lengths, like random graphs. We call them 'small-world' networks, by analogy with the small-world phenomenon (popularly known as six degrees of separation. The neural network of the worm Caenorhabditis elegans, the power grid of the western United States, and the collaboration graph of film actors are shown to be small-world networks. Models of dynamical systems with small-world coupling display enhanced signal-propagation speed, computational power, and synchronizability. In particular, infectious diseases spread more easily in small-world networks than in regular lattices.

Extending the Ground Force Network: Aerial Layer Networking

DTIC Science & Technology

2013-04-25

Additionally aerial layer networks are envisioned to augment the Global Information Grid ( GIG ) access, which is currently provided by the surface...frequencies such as HF, VHF, and UHF. This enabled ground forces to establish tactical wide area networks (WAN) and permitted entry to the GIG ...PRC-117G. Both systems are unique in their overall mission sets, but both provide tactical users access to the WAN and GIG . Self-forming and self

Integration of the White Sands Complex into a Wide Area Network

NASA Technical Reports Server (NTRS)

Boucher, Phillip Larry; Horan, Sheila, B.

1996-01-01

The NASA White Sands Complex (WSC) satellite communications facility consists of two main ground stations, an auxiliary ground station, a technical support facility, and a power plant building located on White Sands Missile Range. When constructed, terrestrial communication access to these facilities was limited to copper telephone circuits. There was no local or wide area communications network capability. This project incorporated a baseband local area network (LAN) topology at WSC and connected it to NASA's wide area network using the Program Support Communications Network-Internet (PSCN-I). A campus-style LAN is configured in conformance with the International Standards Organization (ISO) Open Systems Interconnect (ISO) model. Ethernet provides the physical and data link layers. Transmission Control Protocol and Internet Protocol (TCP/IP) are used for the network and transport layers. The session, presentation, and application layers employ commercial software packages. Copper-based Ethernet collision domains are constructed in each of the primary facilities and these are interconnected by routers over optical fiber links. The network and each of its collision domains are shown to meet IEEE technical configuration guidelines. The optical fiber links are analyzed for the optical power budget and bandwidth allocation and are found to provide sufficient margin for this application. Personal computers and work stations attached to the LAN communicate with and apply a wide variety of local and remote administrative software tools. The Internet connection provides wide area network (WAN) electronic access to other NASA centers and the world wide web (WWW). The WSC network reduces and simplifies the administrative workload while providing enhanced and advanced inter-communications capabilities among White Sands Complex departments and with other NASA centers.

LDCM Ground System. Network Lesson Learned

NASA Technical Reports Server (NTRS)

Gal-Edd, Jonathan

2010-01-01

This slide presentation reviews the Landsat Data Continuity Mission (LDCM) and the lessons learned in implementing the network that was assembled to allow for the acquisition, archiving and distribution of the data from the Landsat mission. The objective of the LDCM is to continue the acquisition, archiving, and distribution of moderate-resolution multispectral imagery affording global, synoptic, and repetitive coverage of the earth's land surface at a scale where natural and human-induced changes can be detected, differentiated, characterized, and monitored over time. It includes a review of the ground network, including a block diagram of the ground network elements (GNE) and a review of the RF design and testing. Also included is a listing of the lessons learned.

Real-time neural network earthquake profile predictor

DOEpatents

Leach, R.R.; Dowla, F.U.

1996-02-06

A neural network has been developed that uses first-arrival energy to predict the characteristics of impending earthquake seismograph signals. The propagation of ground motion energy through the earth is a highly nonlinear function. This is due to different forms of ground motion as well as to changes in the elastic properties of the media throughout the propagation path. The neural network is trained using seismogram data from earthquakes. Presented with a previously unseen earthquake, the neural network produces a profile of the complete earthquake signal using data from the first seconds of the signal. This offers a significant advance in the real-time monitoring, warning, and subsequent hazard minimization of catastrophic ground motion. 17 figs.

Real-time neural network earthquake profile predictor

DOEpatents

Leach, Richard R.; Dowla, Farid U.

1996-01-01

A neural network has been developed that uses first-arrival energy to predict the characteristics of impending earthquake seismograph signals. The propagation of ground motion energy through the earth is a highly nonlinear function. This is due to different forms of ground motion as well as to changes in the elastic properties of the media throughout the propagation path. The neural network is trained using seismogram data from earthquakes. Presented with a previously unseen earthquake, the neural network produces a profile of the complete earthquake signal using data from the first seconds of the signal. This offers a significant advance in the real-time monitoring, warning, and subsequent hazard minimization of catastrophic ground motion.

Assimilation of Spatially Sparse In Situ Soil Moisture Networks into a Continuous Model Domain

NASA Astrophysics Data System (ADS)

Gruber, A.; Crow, W. T.; Dorigo, W. A.

2018-02-01

Growth in the availability of near-real-time soil moisture observations from ground-based networks has spurred interest in the assimilation of these observations into land surface models via a two-dimensional data assimilation system. However, the design of such systems is currently hampered by our ignorance concerning the spatial structure of error afflicting ground and model-based soil moisture estimates. Here we apply newly developed triple collocation techniques to provide the spatial error information required to fully parameterize a two-dimensional (2-D) data assimilation system designed to assimilate spatially sparse observations acquired from existing ground-based soil moisture networks into a spatially continuous Antecedent Precipitation Index (API) model for operational agricultural drought monitoring. Over the contiguous United States (CONUS), the posterior uncertainty of surface soil moisture estimates associated with this 2-D system is compared to that obtained from the 1-D assimilation of remote sensing retrievals to assess the value of ground-based observations to constrain a surface soil moisture analysis. Results demonstrate that a fourfold increase in existing CONUS ground station density is needed for ground network observations to provide a level of skill comparable to that provided by existing satellite-based surface soil moisture retrievals.

Land-mobile satellite communication system

NASA Technical Reports Server (NTRS)

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

1993-01-01

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.

Ground potential rise characteristics of urban step-down substations fed by power cables - A practical example

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sobral, S.T.; Barbosa, J.O.; Numes, J.V.C.

1988-10-01

This paper shows some special ground potential rise characteristics of substations fed by power cables. These characteristics were detected during the study of the interconnected ground system of 14 step-down urban substations fed by the 138 kV underground cable network serving the South Zone of Rio de Janeiro city in Brazil. As this type of system is very common in large cities, the subject can be of general interest for the industry. It was verified that when a fault occurs at a ''cable substation'' (a substation fed exclusively by power cables), almost no ground potential effects were detected at themore » faulted substation or at the other ''cable substations'' of the 138 kV network. However, high values of ground potential occurred at the ''transition substations'' (substations in which the power cables are connected to overhead 138 kV transmission lines, with steel groundwires). That ground potential was enough to produce shocks and equipment damage in certain ''transition substations''. It was verified that this problem has no relation with potential transfer. The paper shows also that the utilization of overhead lines with ACSR groundwires on the initial spans closer to the ''transition substation'' would be enough to avoid the problem. Even if the ACSR conductor is used only at the initial section of one of the lines, a reduction of the problem would be obtained. The paper shows also that the utilization of ACSR ground-wires near the ''transition substations'' contributes to reduce the amount of the copper necessary to control step, touch and mess potentials in these substations. Additional mitigation procedures are also examined in the paper.« less

UAV Trajectory Modeling Using Neural Networks

NASA Technical Reports Server (NTRS)

Xue, Min

2017-01-01

Large amount of small Unmanned Aerial Vehicles (sUAVs) are projected to operate in the near future. Potential sUAV applications include, but not limited to, search and rescue, inspection and surveillance, aerial photography and video, precision agriculture, and parcel delivery. sUAVs are expected to operate in the uncontrolled Class G airspace, which is at or below 500 feet above ground level (AGL), where many static and dynamic constraints exist, such as ground properties and terrains, restricted areas, various winds, manned helicopters, and conflict avoidance among sUAVs. How to enable safe, efficient, and massive sUAV operations at the low altitude airspace remains a great challenge. NASA's Unmanned aircraft system Traffic Management (UTM) research initiative works on establishing infrastructure and developing policies, requirement, and rules to enable safe and efficient sUAVs' operations. To achieve this goal, it is important to gain insights of future UTM traffic operations through simulations, where the accurate trajectory model plays an extremely important role. On the other hand, like what happens in current aviation development, trajectory modeling should also serve as the foundation for any advanced concepts and tools in UTM. Accurate models of sUAV dynamics and control systems are very important considering the requirement of the meter level precision in UTM operations. The vehicle dynamics are relatively easy to derive and model, however, vehicle control systems remain unknown as they are usually kept by manufactures as a part of intellectual properties. That brings challenges to trajectory modeling for sUAVs. How to model the vehicle's trajectories with unknown control system? This work proposes to use a neural network to model a vehicle's trajectory. The neural network is first trained to learn the vehicle's responses at numerous conditions. Once being fully trained, given current vehicle states, winds, and desired future trajectory, the neural network should be able to predict the vehicle's future states at next time step. A complete 4-D trajectory are then generated step by step using the trained neural network. Experiments in this work show that the neural network can approximate the sUAV's model and predict the trajectory accurately.

MicroSensors Systems: detection of a dismounted threat

NASA Astrophysics Data System (ADS)

Davis, Bill; Berglund, Victor; Falkofske, Dwight; Krantz, Brian

2005-05-01

The Micro Sensor System (MSS) is a layered sensor network with the goal of detecting dismounted threats approaching high value assets. A low power unattended ground sensor network is dependant on a network protocol for efficiency in order to minimize data transmissions after network establishment. The reduction of network 'chattiness' is a primary driver for minimizing power consumption and is a factor in establishing a low probability of detection and interception. The MSS has developed a unique protocol to meet these challenges. Unattended ground sensor systems are most likely dependant on batteries for power which due to size determines the ability of the sensor to be concealed after placement. To minimize power requirements, overcome size limitations, and maintain a low system cost the MSS utilizes advanced manufacturing processes know as Fluidic Self-Assembly and Chip Scale Packaging. The type of sensing element and the ability to sense various phenomenologies (particularly magnetic) at ranges greater than a few meters limits the effectiveness of a system. The MicroSensor System will overcome these limitations by deploying large numbers of low cost sensors, which is made possible by the advanced manufacturing process used in production of the sensors. The MSS program will provide unprecedented levels of real-time battlefield information which greatly enhances combat situational awareness when integrated with the existing Command, Control, Communications, Computers, Intelligence, Surveillance and Reconnaissance (C4ISR) infrastructure. This system will provide an important boost to realizing the information dominant, network-centric objective of Joint Vision 2020.

Combining GOES-16 Geostationary Lightning Mapper with the ground based Earth Networks Total Lightning Network

NASA Astrophysics Data System (ADS)

Stock, M.; Lapierre, J. L.; Zhu, Y.

2017-12-01

Recently, the Geostationary Lightning Mapper (GLM) began collecting optical data to locate lightning events and flashes over the North and South American continents. This new instrument promises uniformly high detection efficiency (DE) over its entire field of view, with location accuracy on the order of 10 km. In comparison, Earth Networks Total Lightning Networks (ENTLN) has a less uniform coverage, with higher DE in regions with dense sensor coverage, and lower DE with sparse sensor coverage. ENTLN also offers better location accuracy, lightning classification, and peak current estimation for their lightning locations. It is desirable to produce an integrated dataset, combining the strong points of GLM and ENTLN. The easiest way to achieve this is to simply match located lightning processes from each system using time and distance criteria. This simple method will be limited in scope by the uneven coverage of the ground based network. Instead, we will use GLM group locations to look up the electric field change data recorded by ground sensors near each GLM group, vastly increasing the coverage of the ground network. The ground waveforms can then be used for: improvements to differentiation between glint and lightning for GLM, higher precision lighting location, current estimation, and lightning process classification. Presented is an initial implementation of this type of integration using preliminary GLM data, and waveforms from ENTLN.

Competition in collaborative clothing: a qualitative case study of influences on collaborative quality improvement in the ICU.

PubMed

Dainty, Katie N; Scales, Damon C; Sinuff, Tasnim; Zwarenstein, Merrick

2013-04-01

Multiorganisational quality improvement (QI) collaborative networks are promoted for improving quality within healthcare. Recently, several large-scale QI initiatives have been conducted in the intensive care unit (ICU) environment with successful quantitative results. However, the mechanisms through which such networks lead to QI success remain uncertain. We aim to understand ICU staff perspectives on collaborative QI based on involvement in a multiorganisational improvement network and hypothesise about theoretical constructs that might explain the effect of collaboration in such networks. Qualitative study using a modified grounded theory approach. Key informant interviews were conducted with staff from 12 community hospital ICUs that participated in a cluster randomized control trial (RCT) of a QI intervention using a collaborative approach between 2006 and 2008. Data analysis followed the standard procedure for grounded theory using constant comparative methodology. The collaborative network was perceived to promote increased intrateam cooperation over interorganisational cooperation, but friendly competition with other ICUs appeared to be a prominent driver of behaviour change. Bedsides, clinicians reported that belonging to a collaborative network provided recognition for the high-quality patient care that they already provided. However, the existing communication structure was perceived to be ineffective for staff engagement since it was based on a hierarchical approach to knowledge transfer and project awareness. QI collaborative networks may promote behaviour change by improving intrateam communication, fostering competition with other institutions, and increasing recognition for providing high-quality care. Other commonly held assumptions about their potential impact, for instance, increasing interorganisational legitimisation, communication and collaboration, may be less important.

Unmanned Aerial Vehicle Systems for Remote Estimation of Flooded Areas Based on Complex Image Processing.

PubMed

Popescu, Dan; Ichim, Loretta; Stoican, Florin

2017-02-23

Floods are natural disasters which cause the most economic damage at the global level. Therefore, flood monitoring and damage estimation are very important for the population, authorities and insurance companies. The paper proposes an original solution, based on a hybrid network and complex image processing, to this problem. As first novelty, a multilevel system, with two components, terrestrial and aerial, was proposed and designed by the authors as support for image acquisition from a delimited region. The terrestrial component contains a Ground Control Station, as a coordinator at distance, which communicates via the internet with more Ground Data Terminals, as a fixed nodes network for data acquisition and communication. The aerial component contains mobile nodes-fixed wing type UAVs. In order to evaluate flood damage, two tasks must be accomplished by the network: area coverage and image processing. The second novelty of the paper consists of texture analysis in a deep neural network, taking into account new criteria for feature selection and patch classification. Color and spatial information extracted from chromatic co-occurrence matrix and mass fractal dimension were used as well. Finally, the experimental results in a real mission demonstrate the validity of the proposed methodologies and the performances of the algorithms.

Unmanned Aerial Vehicle Systems for Remote Estimation of Flooded Areas Based on Complex Image Processing

PubMed Central

Popescu, Dan; Ichim, Loretta; Stoican, Florin

2017-01-01

Floods are natural disasters which cause the most economic damage at the global level. Therefore, flood monitoring and damage estimation are very important for the population, authorities and insurance companies. The paper proposes an original solution, based on a hybrid network and complex image processing, to this problem. As first novelty, a multilevel system, with two components, terrestrial and aerial, was proposed and designed by the authors as support for image acquisition from a delimited region. The terrestrial component contains a Ground Control Station, as a coordinator at distance, which communicates via the internet with more Ground Data Terminals, as a fixed nodes network for data acquisition and communication. The aerial component contains mobile nodes—fixed wing type UAVs. In order to evaluate flood damage, two tasks must be accomplished by the network: area coverage and image processing. The second novelty of the paper consists of texture analysis in a deep neural network, taking into account new criteria for feature selection and patch classification. Color and spatial information extracted from chromatic co-occurrence matrix and mass fractal dimension were used as well. Finally, the experimental results in a real mission demonstrate the validity of the proposed methodologies and the performances of the algorithms. PMID:28241479

Operational training for the mission operations at the Brazilian National Institute for Space Research (INPE)

NASA Technical Reports Server (NTRS)

Rozenfeld, Pawel

1993-01-01

This paper describes the selection and training process of satellite controllers and data network operators performed at INPE's Satellite Tracking and Control Center in order to prepare them for the mission operations of the INPE's first (SCD1) satellite. An overview of the ground control system and SCD1 architecture and mission is given. Different training phases are described, taking into account that the applicants had no previous knowledge of space operations requiring, therefore, a training which started from the basics.

Peer network influence on intimate partner violence perpetration among urban Tanzanian men.

PubMed

Mulawa, Marta I; Kajula, Lusajo J; Maman, Suzanne

2018-04-01

Male perpetration of intimate partner violence (IPV) against women in Tanzania is widespread. Theory and empirical evidence suggest peer networks may play an important role in shaping IPV perpetration, although research on this topic in sub-Saharan Africa is limited. Grounded in social learning theory, social influence theory, and the theory of gender and power, the purpose of this study was to examine whether and how peer networks influence men's perpetration of IPV in Dar es Salaam, Tanzania. We conducted in-depth interviews (n = 40) with a sub-sample of 20 men enrolled in the control condition of an ongoing cluster-randomised controlled trial. We purposively sampled participants who previously reported perpetrating physical IPV. To analyse the data, we generated narrative summaries and conducted thematic and interpretative coding. We saw no evidence that men self-selected into peer networks with certain values or behaviours. Rather, men described several mechanisms through which their peers influenced the perpetration of IPV, including: (1) the internalisation of peer network norms, (2) pressure to conform to peer network norms and (3) the direct involvement of peers in shaping couple power dynamics. Our findings suggest that peer networks influence men's perpetration of IPV and should be targeted in future programmes and interventions.

Approximating quantum many-body wave functions using artificial neural networks

NASA Astrophysics Data System (ADS)

Cai, Zi; Liu, Jinguo

2018-01-01

In this paper, we demonstrate the expressibility of artificial neural networks (ANNs) in quantum many-body physics by showing that a feed-forward neural network with a small number of hidden layers can be trained to approximate with high precision the ground states of some notable quantum many-body systems. We consider the one-dimensional free bosons and fermions, spinless fermions on a square lattice away from half-filling, as well as frustrated quantum magnetism with a rapidly oscillating ground-state characteristic function. In the latter case, an ANN with a standard architecture fails, while that with a slightly modified one successfully learns the frustration-induced complex sign rule in the ground state and approximates the ground states with high precisions. As an example of practical use of our method, we also perform the variational method to explore the ground state of an antiferromagnetic J1-J2 Heisenberg model.

A proposed ground-water quality monitoring network for Idaho

USGS Publications Warehouse

Whitehead, R.L.; Parliman, D.J.

1979-01-01

A ground water quality monitoring network is proposed for Idaho. The network comprises 565 sites, 8 of which will require construction of new wells. Frequencies of sampling at the different sites are assigned at quarterly, semiannual, annual, and 5 years. Selected characteristics of the water will be monitored by both laboratory- and field-analysis methods. The network is designed to: (1) Enable water managers to keep abreast of the general quality of the State 's ground water, and (2) serve as a warning system for undesirable changes in ground-water quality. Data were compiled for hydrogeologic conditions, ground-water quality, cultural elements, and pollution sources. A ' hydrologic unit priority index ' is used to rank 84 hydrologic units (river basins or segments of river basins) of the State for monitoring according to pollution potential. Emphasis for selection of monitoring sites is placed on the 15 highest ranked units. The potential for pollution is greatest in areas of privately owned agricultural land. Other areas of pollution potential are residential development, mining and related processes, and hazardous waste disposal. Data are given for laboratory and field analyses, number of site visits, manpower, subsistence, and mileage, from which costs for implementing the network can be estimated. Suggestions are made for data storage and retrieval and for reporting changes in water quality. (Kosco-USGS)

The contribution of geology and groundwater studies to city-scale ground heat network strategies: A case study from Cardiff, UK

NASA Astrophysics Data System (ADS)

Boon, David; Farr, Gareth; Patton, Ashley; Kendall, Rhian; James, Laura; Abesser, Corinna; Busby, Jonathan; Schofield, David; White, Debbie; Gooddy, Daren; James, David; Williams, Bernie; Tucker, David; Knowles, Steve; Harcombe, Gareth

2016-04-01

The development of integrated heat network strategies involving exploitation of the shallow subsurface requires knowledge of ground conditions at the feasibility stage, and throughout the life of the system. We describe an approach to the assessment of ground constraints and energy opportunities in data-rich urban areas. Geological and hydrogeological investigations have formed a core component of the strategy development for sustainable thermal use of the subsurface in Cardiff, UK. We present findings from a 12 month project titled 'Ground Heat Network at a City Scale', which was co-funded by NERC/BGS and the UK Government through the InnovateUK Energy Catalyst grant in 2015-16. The project examined the technical feasibility of extracting low grade waste heat from a shallow gravel aquifer using a cluster of open loop ground source heat pumps. Heat demand mapping was carried out separately. The ground condition assessment approach involved the following steps: (1) city-wide baseline groundwater temperature mapping in 2014 with seasonal monitoring for at least 12 months prior to heat pump installation (Patton et al 2015); (2) desk top and field-based investigation of the aquifer system to determine groundwater levels, likely flow directions, sustainable pumping yields, water chemistry, and boundary conditions; (3) creation of a 3D geological framework model with physical property testing and model attribution; (4) use steps 1-3 to develop conceptual ground models and production of maps and GIS data layers to support scenario planning, and initial heat network concept designs; (5) heat flow modelling in FEFLOW software to analyse sustainability and predict potential thermal breakthrough in higher risk areas; (6) installation of a shallow open loop GSHP research observatory with real-time monitoring of groundwater bodies to provide data for heat flow model validation and feedback for system control. In conclusion, early ground condition modelling and subsurface monitoring have provided an initial indication of ground constraints and opportunities supporting development of aquifer thermal energy systems in Cardiff. Ground models should consider the past and future anthropogenic processes that influence and modify the condition of the ground. These include heat losses from buildings, modification of the groundwater regime by artificial pumping, sewers, and other GSH schemes, and construction hazards such as buried infrastructure, old foundations, land contamination and un-exploded ordnance. This knowledge base forms the foundation for a 'whole life' approach for sustainable thermal use of the subsurface. Benefits of the approach include; timely and easy to understand information for land use and financial resource planning, reduced financial risk for developers and investors, clear evidence to help improve public perception of GSHP technology, and provision of independent environmental data to satisfy the needs of the regulator. References: Patton, A.M., Farr, G.J., Boon, D.P., James, D.R., Williams, B., Newell, A.J. 2015. Shallow Groundwater Temperatures and the Urban Heat Island Effect: the First U.K City-wide Geothermal Map to Support Development of Ground Source Heating Systems Strategy. Geophysical Research Abstracts. EGU 2015 Vienna, Austria. (Poster)

Digital Elevation Models of the Pre-Eruption 2000 Crater and 2004-07 Dome-Building Eruption at Mount St. Helens, Washington, USA

USGS Publications Warehouse

Messerich, J.A.; Schilling, S.P.; Thompson, R.A.

2008-01-01

Presented in this report are 27 digital elevation model (DEM) datasets for the crater area of Mount St. Helens. These datasets include pre-eruption baseline data collected in 2000, incremental model subsets collected during the 2004-07 dome building eruption, and associated shaded-relief image datasets. Each dataset was collected photogrammetrically with digital softcopy methods employing a combination of manual collection and iterative compilation of x,y,z coordinate triplets utilizing autocorrelation techniques. DEM data points collected using autocorrelation methods were rigorously edited in stereo and manually corrected to ensure conformity with the ground surface. Data were first collected as a triangulated irregular network (TIN) then interpolated to a grid format. DEM data are based on aerotriangulated photogrammetric solutions for aerial photograph strips flown at a nominal scale of 1:12,000 using a combination of surveyed ground control and photograph-identified control points. The 2000 DEM is based on aerotriangulation of four strips totaling 31 photographs. Subsequent DEMs collected during the course of the eruption are based on aerotriangulation of single aerial photograph strips consisting of between three and seven 1:12,000-scale photographs (two to six stereo pairs). Most datasets were based on three or four stereo pairs. Photogrammetric errors associated with each dataset are presented along with ground control used in the photogrammetric aerotriangulation. The temporal increase in area of deformation in the crater as a result of dome growth, deformation, and translation of glacial ice resulted in continual adoption of new ground control points and abandonment of others during the course of the eruption. Additionally, seasonal snow cover precluded the consistent use of some ground control points.

Mobile User Objective System (MUOS)

DTIC Science & Technology

2015-12-01

the current UHF Follow-On ( UFO ) constellation. MUOS includes the satellite constellation, a ground control and network management system, and a new...MUOS CAI. Each MUOS satellite carries a legacy payload similar to that flown on UFO -11. These legacy payloads will continue to support legacy...Antecedent Information The antecedent system to MUOS was the Ultra High Frequency (UHF) Follow-on ( UFO ) satellite communications program. Comparisons

Coordinating complex problem-solving among distributed intelligent agents

NASA Technical Reports Server (NTRS)

Adler, Richard M.

1992-01-01

A process-oriented control model is described for distributed problem solving. The model coordinates the transfer and manipulation of information across independent networked applications, both intelligent and conventional. The model was implemented using SOCIAL, a set of object-oriented tools for distributing computing. Complex sequences of distributed tasks are specified in terms of high level scripts. Scripts are executed by SOCIAL objects called Manager Agents, which realize an intelligent coordination model that routes individual tasks to suitable server applications across the network. These tools are illustrated in a prototype distributed system for decision support of ground operations for NASA's Space Shuttle fleet.

Validation and understanding of Moderate Resolution Imaging Spectroradiometer aerosol products (C5) using ground-based measurements from the handheld Sun photometer network in China

Treesearch

Zhanqing Li; Feng Niu; Kwon-Ho Lee; Jinyuan Xin; Wei Min Hao; Bryce L. Nordgren; Yuesi Wang; Pucai Wang

2007-01-01

The Moderate Resolution Imaging Spectroradiometer (MODIS) currently provides the most extensive aerosol retrievals on a global basis, but validation is limited to a small number of ground stations. This study presents a comprehensive evaluation of Collection 4 and 5 MODIS aerosol products using ground measurements from the Chinese Sun Hazemeter Network (CSHNET). The...

Holographic neural networks versus conventional neural networks: a comparative evaluation for the classification of landmine targets in ground-penetrating radar images

NASA Astrophysics Data System (ADS)

Mudigonda, Naga R.; Kacelenga, Ray; Edwards, Mark

2004-09-01

This paper evaluates the performance of a holographic neural network in comparison with a conventional feedforward backpropagation neural network for the classification of landmine targets in ground penetrating radar images. The data used in the study was acquired from four different test sites using the landmine detection system developed by General Dynamics Canada Ltd., in collaboration with the Defense Research and Development Canada, Suffield. A set of seven features extracted for each detected alarm is used as stimulus inputs for the networks. The recall responses of the networks are then evaluated against the ground truth to declare true or false detections. The area computed under the receiver operating characteristic curve is used for comparative purposes. With a large dataset comprising of data from multiple sites, both the holographic and conventional networks showed comparable trends in recall accuracies with area values of 0.88 and 0.87, respectively. By using independent validation datasets, the holographic network"s generalization performance was observed to be better (mean area = 0.86) as compared to the conventional network (mean area = 0.82). Despite the widely publicized theoretical advantages of the holographic technology, use of more than the required number of cortical memory elements resulted in an over-fitting phenomenon of the holographic network.

Remote sensing of GHG over Paris megacity and Orléans forest using ground-based QualAir FTS and TCCON-Orléans

NASA Astrophysics Data System (ADS)

Te, Y.; Jeseck, P.; Da Costa, J.; Deutscher, N. M.; Warneke, T.; Notholt, J.

2012-04-01

In a growing world with more than 7 billion inhabitants and big emerging countries such as China, Brazil and India, emissions of anthropogenic pollutants are increasing continuously. Monitoring and control of atmospheric pollutants in megacities have become a major challenge for scientists and public health authorities in environmental research area. The QualAir platform at University Pierre et Marie Curie (UPMC), is an innovating experimental research platform dedicated to survey greenhouse gases (GHGs) and urban air quality. As one of the major instruments of the QualAir platform, the ground-based Fourier transform spectrometer (QualAir FTS, IFS 125HR model) analyses the composition of the urban atmosphere of Paris, which is the third European megacity. The continuous monitoring of atmospheric pollutants is essential to improve the understanding of urban air pollution processes. Associated with a sun-tracker, the QualAir remote sensing FTS operates in solar infrared absorption and enables to monitor many trace gases, and to follow up their variability in the Ile-de-France region. A description of the QualAir FTS will be given. Concentrations of atmospheric GHG, especially CO2 and CH4, are retrieved by the radiative transfer model PROFFIT. Located in the centre of Paris, the QualAir FTS can provide new and complementary urban measurements as compared to unpolluted ground-based stations of existing networks (NDACC and TCCON). The work made by LPMAA to join the TCCON network will also be presented. TCCON-Orléans is a ground-based FTS of the TCCON network located in the forest of Orléans (100 km south of Paris). Preliminary comparisons of GHGs measurements from both sites will be shown. Such ground-based information will help to better characterize regional GHGs, especially regarding anthropogenic emissions and trends.

Tracking Data Certification for the Lunar Reconnaissance Orbiter

NASA Technical Reports Server (NTRS)

Morinelli, Patrick J.; Socoby, Joseph; Hendry, Steve; Campion, Richard

2010-01-01

This paper details the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) Flight Dynamics Facility (FDF) tracking data certification effort of the Lunar Reconnaissance Orbiter (LRO) Space Communications Network (SCN) complement of tracking stations consisting of the NASA White Sands 1 antenna (WS1), and the commercial provider Universal Space Network (USN) antennas at South Point, Hawaii; Dongara Australia; Weilheim, Germany; and Kiruna, Sweden. Certification assessment required the cooperation and coordination of parties not under the control of either the LRO project or ground stations as uplinks on cooperating spacecraft were necessary. The LRO range-tracking requirement of 10m 1 sigma could be satisfactorily demonstrated using any typical spacecraft capable of range tracking. Though typical Low Earth Orbiting (LEO) or Geosynchronous Earth Orbiting (GEO) spacecraft may be adequate for range certification, their measurement dynamics and noise would be unacceptable for proper Doppler certification of 1-3mm/sec 1 sigma. As LRO will orbit the Moon, it was imperative that a suitable target spacecraft be utilized which can closely mimic the expected lunar orbital Doppler dynamics of +/-1.6km/sec and +/-1.5m/sq sec to +/-0.15m/sq sec, is in view of the ground stations, supports coherent S-Band Doppler tracking measurements, and can be modeled by the FDF. In order to meet the LRO metric tracking data specifications, the SCN ground stations employed previously uncertified numerically controlled tracking receivers. Initial certification testing revealed certain characteristics of the units that required resolution before being granted certification.

A model for characterizing residential ground current and magnetic field fluctuations.

PubMed

Mader, D L; Peralta, S B; Sherar, M D

1994-01-01

The current through the residential grounding circuit is an important source for magnetic fields; field variations near the grounding circuit accurately track fluctuations in this ground current. In this paper, a model is presented which permits calculation of the range of these fluctuations. A discrete network model is used to simulate a local distribution system for a single street, and a statistical model to simulate unbalanced currents in the system. Simulations of three-house and ten-house networks show that random appliance operation leads to ground current fluctuations which can be quite large, on the order of 600%. This is consistent with measured fluctuations in an actual house.

Integrated Module and Gene-Specific Regulatory Inference Implicates Upstream Signaling Networks

PubMed Central

Roy, Sushmita; Lagree, Stephen; Hou, Zhonggang; Thomson, James A.; Stewart, Ron; Gasch, Audrey P.

2013-01-01

Regulatory networks that control gene expression are important in diverse biological contexts including stress response and development. Each gene's regulatory program is determined by module-level regulation (e.g. co-regulation via the same signaling system), as well as gene-specific determinants that can fine-tune expression. We present a novel approach, Modular regulatory network learning with per gene information (MERLIN), that infers regulatory programs for individual genes while probabilistically constraining these programs to reveal module-level organization of regulatory networks. Using edge-, regulator- and module-based comparisons of simulated networks of known ground truth, we find MERLIN reconstructs regulatory programs of individual genes as well or better than existing approaches of network reconstruction, while additionally identifying modular organization of the regulatory networks. We use MERLIN to dissect global transcriptional behavior in two biological contexts: yeast stress response and human embryonic stem cell differentiation. Regulatory modules inferred by MERLIN capture co-regulatory relationships between signaling proteins and downstream transcription factors thereby revealing the upstream signaling systems controlling transcriptional responses. The inferred networks are enriched for regulators with genetic or physical interactions, supporting the inference, and identify modules of functionally related genes bound by the same transcriptional regulators. Our method combines the strengths of per-gene and per-module methods to reveal new insights into transcriptional regulation in stress and development. PMID:24146602

Technology Developments Integrating a Space Network Communications Testbed

NASA Technical Reports Server (NTRS)

Kwong, Winston; Jennings, Esther; Clare, Loren; Leang, Dee

2006-01-01

As future manned and robotic space explorations missions involve more complex systems, it is essential to verify, validate, and optimize such systems through simulation and emulation in a low cost testbed environment. The goal of such a testbed is to perform detailed testing of advanced space and ground communications networks, technologies, and client applications that are essential for future space exploration missions. We describe the development of new technologies enhancing our Multi-mission Advanced Communications Hybrid Environment for Test and Evaluation (MACHETE) that enable its integration in a distributed space communications testbed. MACHETE combines orbital modeling, link analysis, and protocol and service modeling to quantify system performance based on comprehensive considerations of different aspects of space missions. It can simulate entire networks and can interface with external (testbed) systems. The key technology developments enabling the integration of MACHETE into a distributed testbed are the Monitor and Control module and the QualNet IP Network Emulator module. Specifically, the Monitor and Control module establishes a standard interface mechanism to centralize the management of each testbed component. The QualNet IP Network Emulator module allows externally generated network traffic to be passed through MACHETE to experience simulated network behaviors such as propagation delay, data loss, orbital effects and other communications characteristics, including entire network behaviors. We report a successful integration of MACHETE with a space communication testbed modeling a lunar exploration scenario. This document is the viewgraph slides of the presentation.

Design of Distributed Controllers Seeking Optimal Power Flow Solutions Under Communication Constraints

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dall'Anese, Emiliano; Simonetto, Andrea; Dhople, Sairaj

This paper focuses on power distribution networks featuring inverter-interfaced distributed energy resources (DERs), and develops feedback controllers that drive the DER output powers to solutions of time-varying AC optimal power flow (OPF) problems. Control synthesis is grounded on primal-dual-type methods for regularized Lagrangian functions, as well as linear approximations of the AC power-flow equations. Convergence and OPF-solution-tracking capabilities are established while acknowledging: i) communication-packet losses, and ii) partial updates of control signals. The latter case is particularly relevant since it enables asynchronous operation of the controllers where DER setpoints are updated at a fast time scale based on local voltagemore » measurements, and information on the network state is utilized if and when available, based on communication constraints. As an application, the paper considers distribution systems with high photovoltaic integration, and demonstrates that the proposed framework provides fast voltage-regulation capabilities, while enabling the near real-time pursuit of solutions of AC OPF problems.« less

Design of Distributed Controllers Seeking Optimal Power Flow Solutions under Communication Constraints: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dall'Anese, Emiliano; Simonetto, Andrea; Dhople, Sairaj

This paper focuses on power distribution networks featuring inverter-interfaced distributed energy resources (DERs), and develops feedback controllers that drive the DER output powers to solutions of time-varying AC optimal power flow (OPF) problems. Control synthesis is grounded on primal-dual-type methods for regularized Lagrangian functions, as well as linear approximations of the AC power-flow equations. Convergence and OPF-solution-tracking capabilities are established while acknowledging: i) communication-packet losses, and ii) partial updates of control signals. The latter case is particularly relevant since it enables asynchronous operation of the controllers where DER setpoints are updated at a fast time scale based on local voltagemore » measurements, and information on the network state is utilized if and when available, based on communication constraints. As an application, the paper considers distribution systems with high photovoltaic integration, and demonstrates that the proposed framework provides fast voltage-regulation capabilities, while enabling the near real-time pursuit of solutions of AC OPF problems.« less

Catchment-Scale Terrain Modelling with Structure-from-Motion Photogrammetry: a replacement for airborne lidar?

NASA Astrophysics Data System (ADS)

Brasington, J.

2015-12-01

Over the last five years, Structure-from-Motion photogrammetry has dramatically democratized the availability of high quality topographic data. This approach involves the use of a non-linear bundle adjustment to estimate simultaneously camera position, pose, distortion and 3D model coordinates. In contrast to traditional aerial photogrammetry, the bundle adjustment is typically solved without external constraints and instead ground control is used a posteriori to transform the modelled coordinates to an established datum using a similarity transformation. The limited data requirements, coupled with the ability to self-calibrate compact cameras, has led to a burgeoning of applications using low-cost imagery acquired terrestrially or from low-altitude platforms. To date, most applications have focused on relatively small spatial scales where relaxed logistics permit the use of dense ground control and high resolution, close-range photography. It is less clear whether this low-cost approach can be successfully upscaled to tackle larger, watershed-scale projects extending over 102-3 km2 where it could offer a competitive alternative to landscape modelling with airborne lidar. At such scales, compromises over the density of ground control, the speed and height of sensor platform and related image properties are inevitable. In this presentation we provide a systematic assessment of large-scale SfM terrain products derived for over 80 km2 of the braided Dart River and its catchment in the Southern Alps of NZ. Reference data in the form of airborne and terrestrial lidar are used to quantify the quality of 3D reconstructions derived from helicopter photography and used to establish baseline uncertainty models for geomorphic change detection. Results indicate that camera network design is a key determinant of model quality, and that standard aerial networks based on strips of nadir photography can lead to unstable camera calibration and systematic errors that are difficult to model with sparse ground control. We demonstrate how a low cost multi-camera platform providing both nadir and oblique imagery can support robust camera calibration, enabling the generation of high quality, large-scale terrain products that are suitable for precision fluvial change detection.

An overview of the technical design of MSAT mobile satellite communications services

NASA Astrophysics Data System (ADS)

Davies, N. George

The Canadian MSAT mobile satellite communications system is being implemented in cooperation with the American Mobile Satellite Consortium (AMSC). Two satellites are to be jointly acquired and each satellite is expected to backup the other. This paper describes the technical concepts of the services to be offered and the baseline planning of the infrastructure for the ground segment. MSAT service requirements are analyzed for mobile radio, telephone, data, and aeronautical services. The MSAT system will use nine beams in a narrow range of L-band frequencies with frequency reuse. Beams may be added to cover flight information areas in the Atlantic and Pacific oceans. The elements of the network architecture are: a network control centre, data hub stations, gateway stations, base stations, mobile terminals, and a signalling system to interconnect the elements of the system. The network control center will manage the network and allocate space segment capacity; data hub stations will support a switched packet mobile data service; the gateway stations will provide interconnection to the public telephone system and data networks; and the base stations will support private circuit switched voice and data services. Several alternative designs for the signalling system are described.

Mapping a sensory-motor network onto a structural and functional ground plan in the hindbrain.

PubMed

Koyama, Minoru; Kinkhabwala, Amina; Satou, Chie; Higashijima, Shin-ichi; Fetcho, Joseph

2011-01-18

The hindbrain of larval zebrafish contains a relatively simple ground plan in which the neurons throughout it are arranged into stripes that represent broad neuronal classes that differ in transmitter identity, morphology, and transcription factor expression. Within the stripes, neurons are stacked continuously according to age as well as structural and functional properties, such as axonal extent, input resistance, and the speed at which they are recruited during movements. Here we address the question of how particular networks among the many different sensory-motor networks in hindbrain arise from such an orderly plan. We use a combination of transgenic lines and pairwise patch recording to identify excitatory and inhibitory interneurons in the hindbrain network for escape behaviors initiated by the Mauthner cell. We map this network onto the ground plan to show that an individual hindbrain network is built by drawing components in predictable ways from the underlying broad patterning of cell types stacked within stripes according to their age and structural and functional properties. Many different specialized hindbrain networks may arise similarly from a simple early patterning.

Publication of topographic atlas and control network of Mars

NASA Technical Reports Server (NTRS)

Wu, Sherman S. C.; Billideau, Jennifer S.; Spare, Beth A.

1991-01-01

To aid planetary studies and the planning of future Mars missions, the Topographic Atlas and Control Network for Mars will be submitted by the end of fiscal year 1992 for publication as a NASA Special Publication. It will consist of reduced versions of 108 1:2 million-scale photomosaics that show contour lines from topographic maps at the same scale, as well as precisely located control points. The control points are from the planetwide network, which is not only instrumental in the compilation of maps at various scales, but is also widely used in other research such as studies of Mars' gravity and atmosphere. An example, a combination of MC 8-NW and -SW, of the photomosaics to be included in the atlas is presented. Contour lines in the figure are at 1-km intervals. The final adjusted ground coordinates and elevations of the 77 control points shown are given in table form. The last column in the table lists the topographic datum (zero elevation) that can be used to compute the solid radius of the control point from the center of mass of Mars. The atlas will also include information such as the adjusted C-matrices of each image, descriptions of the methods used, and their accuracy, and guidelines for users.

Space Link Extension Protocol Emulation for High-Throughput, High-Latency Network Connections

NASA Technical Reports Server (NTRS)

Tchorowski, Nicole; Murawski, Robert

2014-01-01

New space missions require higher data rates and new protocols to meet these requirements. These high data rate space communication links push the limitations of not only the space communication links, but of the ground communication networks and protocols which forward user data to remote ground stations (GS) for transmission. The Consultative Committee for Space Data Systems, (CCSDS) Space Link Extension (SLE) standard protocol is one protocol that has been proposed for use by the NASA Space Network (SN) Ground Segment Sustainment (SGSS) program. New protocol implementations must be carefully tested to ensure that they provide the required functionality, especially because of the remote nature of spacecraft. The SLE protocol standard has been tested in the NASA Glenn Research Center's SCENIC Emulation Lab in order to observe its operation under realistic network delay conditions. More specifically, the delay between then NASA Integrated Services Network (NISN) and spacecraft has been emulated. The round trip time (RTT) delay for the continental NISN network has been shown to be up to 120ms; as such the SLE protocol was tested with network delays ranging from 0ms to 200ms. Both a base network condition and an SLE connection were tested with these RTT delays, and the reaction of both network tests to the delay conditions were recorded. Throughput for both of these links was set at 1.2Gbps. The results will show that, in the presence of realistic network delay, the SLE link throughput is significantly reduced while the base network throughput however remained at the 1.2Gbps specification. The decrease in SLE throughput has been attributed to the implementation's use of blocking calls. The decrease in throughput is not acceptable for high data rate links, as the link requires constant data a flow in order for spacecraft and ground radios to stay synchronized, unless significant data is queued a the ground station. In cases where queuing the data is not an option, such as during real time transmissions, the SLE implementation cannot support high data rate communication.

A comparison of two ground-based lightning detection networks against the satellite-based lightning imaging sensor (LIS)

NASA Astrophysics Data System (ADS)

Thompson, Kelsey B.

We compared lightning stroke data from the ground-based World Wide Lightning Location Network (WWLLN) and lightning stroke data from the ground-based Earth Networks Total Lightning Network (ENTLN) to lightning group data from the satellite-based Lightning Imaging Sensor (LIS) from 1 January 2010 through 30 June 2011. The region of study, about 39°S to 39°N latitude, 164°E to 17°W longitude, chosen to approximate the Geostationary Lightning Mapper (GLM) field of view, was considered in its entirety and then divided into four geographical sub-regions. We found the highest 18-mon WWLLN coincidence percent (CP) value in the Pacific Ocean at 18.9% and the highest 18-mon ENTLN CP value in North America at 63.3%. We found the lowest 18-mon CP value for both WWLLN and ENTLN in South America at 6.2% and 2.2% respectively. Daily CP values and how often large radiance LIS groups had a coincident stroke varied. Coincidences between LIS groups and ENTLN strokes often resulted in more cloud than ground coincidences in North America and more ground than cloud coincidences in the other three sub-regions.

Stress Drop and Depth Controls on Ground Motion From Induced Earthquakes

NASA Astrophysics Data System (ADS)

Baltay, A.; Rubinstein, J. L.; Terra, F. M.; Hanks, T. C.; Herrmann, R. B.

2015-12-01

Induced earthquakes in the central United States pose a risk to local populations, but there is not yet agreement on how to portray their hazard. A large source of uncertainty in the hazard arises from ground motion prediction, which depends on the magnitude and distance of the causative earthquake. However, ground motion models for induced earthquakes may be very different than models previously developed for either the eastern or western United States. A key question is whether ground motions from induced earthquakes are similar to those from natural earthquakes, yet there is little history of natural events in the same region with which to compare the induced ground motions. To address these problems, we explore how earthquake source properties, such as stress drop or depth, affect the recorded ground motion of induced earthquakes. Typically, due to stress drop increasing with depth, ground motion prediction equations model shallower events to have smaller ground motions, when considering the same absolute hypocentral distance to the station. Induced earthquakes tend to occur at shallower depths, with respect to natural eastern US earthquakes, and may also exhibit lower stress drops, which begs the question of how these two parameters interact to control ground motion. Can the ground motions of induced earthquakes simply be understood by scaling our known source-ground motion relations to account for the shallow depth or potentially smaller stress drops of these induced earthquakes, or is there an inherently different mechanism in play for these induced earthquakes? We study peak ground-motion velocity (PGV) and acceleration (PGA) from induced earthquakes in Oklahoma and Kansas, recorded by USGS networks at source-station distances of less than 20 km, in order to model the source effects. We compare these records to those in both the NGA-West2 database (primarily from California) as well as NGA-East, which covers the central and eastern United States and Canada. Preliminary analysis indicates that the induced ground motions appear similar to those from the NGA-West2 database. However, upon consideration of their shallower depths, ground motion behavior from induced events seems to fall in between the West data and that of NGA-East, so we explore the control of stress drop and depth on ground motion in more detail.

Air Traffic Control Improvement Using Prioritized CSMA

NASA Technical Reports Server (NTRS)

Robinson, Daryl C.

2001-01-01

Version 7 simulations of the industry-standard network simulation software "OPNET" are presented of two applications of the Aeronautical Telecommunications Network (ATN), Controller Pilot Data Link Communications (CPDLC) and Automatic Dependent Surveillance-Broadcast mode (ADS-B), over VHF Data Link mode 2 (VDL-2). Communication is modeled for air traffic between just three cities. All aircraft are assumed to have the same equipage. The simulation involves Air Traffic Control (ATC) ground stations and 105 aircraft taking off, flying realistic free-flight trajectories, and landing in a 24-hr period. All communication is modeled as unreliable. Collision-less, prioritized carrier sense multiple access (CSMA) is successfully tested. The statistics presented include latency, queue length, and packet loss. This research may show that a communications system simpler than the currently accepted standard envisioned may not only suffice, but also surpass performance of the standard at a lower cost of deployment.

Landsat's international partners

USGS Publications Warehouse

Byrnes, Raymond A.

2012-01-01

Since the launch of the first Landsat satellite 40 years ago, International Cooperators (ICs) have formed a key strategic alliance with the U.S. Geological Survey (USGS) to not only engage in Landsat data downlink services but also to enable a foundation for scientific and technical collaboration. The map below shows the locations of all ground stations operated by the United States and IC ground station network for the direct downlink and distribution of Landsat 5 (L5) and Landsat 7 (L7) image data. The circles show the approximate area over which each station has the capability for direct reception of Landsat data. The red circles show the components of the L5 ground station network, the green circles show components of the L7 station network, and the dashed circles show stations with dual (L5 and L7) status. The yellow circles show L5 short-term ("campaign") stations that contribute to the USGS Landsat archive. Ground stations in South Dakota and Australia currently serve as the primary data capture facilities for the USGS Landsat Ground Network (LGN). The Landsat Ground Station (LGS) is located at the USGS Earth Resources Observation and Science (EROS) Center in Sioux Falls, South Dakota. The Alice Springs (ASN) ground station is located at the Geoscience Australia facility in Alice Springs, Australia. These sites receive the image data, via X-band Radio Frequency (RF) link, and the spacecraft housekeeping data, via S-band RF link. LGS also provides tracking services and a command link to the spacecrafts.

SMC: SCENIC Model Control

NASA Technical Reports Server (NTRS)

Srivastava, Priyaka; Kraus, Jeff; Murawski, Robert; Golden, Bertsel, Jr.

2015-01-01

NASAs Space Communications and Navigation (SCaN) program manages three active networks: the Near Earth Network, the Space Network, and the Deep Space Network. These networks simultaneously support NASA missions and provide communications services to customers worldwide. To efficiently manage these resources and their capabilities, a team of student interns at the NASA Glenn Research Center is developing a distributed system to model the SCaN networks. Once complete, the system shall provide a platform that enables users to perform capacity modeling of current and prospective missions with finer-grained control of information between several simulation and modeling tools. This will enable the SCaN program to access a holistic view of its networks and simulate the effects of modifications in order to provide NASA with decisional information. The development of this capacity modeling system is managed by NASAs Strategic Center for Education, Networking, Integration, and Communication (SCENIC). Three primary third-party software tools offer their unique abilities in different stages of the simulation process. MagicDraw provides UMLSysML modeling, AGIs Systems Tool Kit simulates the physical transmission parameters and de-conflicts scheduled communication, and Riverbed Modeler (formerly OPNET) simulates communication protocols and packet-based networking. SCENIC developers are building custom software extensions to integrate these components in an end-to-end space communications modeling platform. A central control module acts as the hub for report-based messaging between client wrappers. Backend databases provide information related to mission parameters and ground station configurations, while the end user defines scenario-specific attributes for the model. The eight SCENIC interns are working under the direction of their mentors to complete an initial version of this capacity modeling system during the summer of 2015. The intern team is composed of four students in Computer Science, two in Computer Engineering, one in Electrical Engineering, and one studying Space Systems Engineering.

Evaluation on surface current observing network of high frequency ground wave radars in the Gulf of Thailand

NASA Astrophysics Data System (ADS)

Yin, Xunqiang; Shi, Junqiang; Qiao, Fangli

2018-05-01

Due to the high cost of ocean observation system, the scientific design of observation network becomes much important. The current network of the high frequency radar system in the Gulf of Thailand has been studied using a three-dimensional coastal ocean model. At first, the observations from current radars have been assimilated into this coastal model and the forecast results have improved due to the data assimilation. But the results also show that further optimization of the observing network is necessary. And then, a series of experiments were carried out to assess the performance of the existing high frequency ground wave radar surface current observation system. The simulated surface current data in three regions were assimilated sequentially using an efficient ensemble Kalman filter data assimilation scheme. The experimental results showed that the coastal surface current observation system plays a positive role in improving the numerical simulation of the currents. Compared with the control experiment without assimilation, the simulation precision of surface and subsurface current had been improved after assimilated the surface currents observed at current networks. However, the improvement for three observing regions was quite different and current observing network in the Gulf of Thailand is not effective and a further optimization is required. Based on these evaluations, a manual scheme has been designed by discarding the redundant and inefficient locations and adding new stations where the performance after data assimilation is still low. For comparison, an objective scheme based on the idea of data assimilation has been obtained. Results show that all the two schemes of observing network perform better than the original network and optimal scheme-based data assimilation is much superior to the manual scheme that based on the evaluation of original observing network in the Gulf of Thailand. The distributions of the optimal network of radars could be a useful guidance for future design of observing system in this region.

Explosion Source Location Study Using Collocated Acoustic and Seismic Networks in Israel

NASA Astrophysics Data System (ADS)

Pinsky, V.; Gitterman, Y.; Arrowsmith, S.; Ben-Horin, Y.

2013-12-01

We explore a joined analysis of seismic and infrasonic signals for improvement in automatic monitoring of small local/regional events, such as construction and quarry blasts, military chemical explosions, sonic booms, etc. using collocated seismic and infrasonic networks recently build in Israel (ISIN) in the frame of the project sponsored by the Bi-national USA-Israel Science Foundation (BSF). The general target is to create an automatic system, which will provide detection, location and identification of explosions in real-time or close-to-real time manner. At the moment the network comprises 15 stations hosting a microphone and seismometer (or accelerometer), operated by the Geophysical Institute of Israel (GII), plus two infrasonic arrays, operated by the National Data Center, Soreq: IOB in the South (Negev desert) and IMA in the North of Israel (Upper Galilee),collocated with the IMS seismic array MMAI. The study utilizes a ground-truth data-base of numerous Rotem phosphate quarry blasts, a number of controlled explosions for demolition of outdated ammunitions and experimental surface explosions for a structure protection research, at the Sayarim Military Range. A special event, comprising four military explosions in a neighboring country, that provided both strong seismic (up to 400 km) and infrasound waves (up to 300 km), is also analyzed. For all of these events the ground-truth coordinates and/or the results of seismic location by the Israel Seismic Network (ISN) have been provided. For automatic event detection and phase picking we tested the new recursive picker, based on Statistically optimal detector. The results were compared to the manual picks. Several location techniques have been tested using the ground-truth event recordings and the preliminary results obtained have been compared to the ground-truth locations: 1) a number of events have been located as intersection of azimuths estimated using the wide-band F-K analysis technique applied to the infrasonic phases of the two distant arrays; 2) a standard robust grid-search location procedure based on phase picks and a constant celerity for a phase (tropospheric or stratospheric) was applied; 3) a joint coordinate grid-search procedure using array waveforms and phase picks was tested, 4) the Bayesian Infrasonic Source Localization (BISL) method, incorporating semi-empirical model-based prior information, was modified for array+network configuration and applied to the ground-truth events. For this purpose we accumulated data of the former observations of the air-to-ground infrasonic phases to compute station specific ground-truth Celerity-Range Histograms (ssgtCRH) and/or model-based CRH (mbCRH), which allow to essentially improve the location results. For building the mbCRH the local meteo-data and the ray-tracing modeling in 3 available azimuth ranges, accounting seasonal variations of winds directivity (quadrants North:315-45, South: 135-225, East 45-135) have been used.

Predicting cloud-to-ground lightning with neural networks

NASA Technical Reports Server (NTRS)

Barnes, Arnold A., Jr.; Frankel, Donald; Draper, James Stark

1991-01-01

A neural network is being trained to predict lightning at Cape Canaveral for periods up to two hours in advance. Inputs consist of ground based field mill data, meteorological tower data, lightning location data, and radiosonde data. High values of the field mill data and rapid changes in the field mill data, offset in time, provide the forecasts or desired output values used to train the neural network through backpropagation. Examples of input data are shown and an example of data compression using a hidden layer in the neural network is discussed.

Conceptual Design of a Communication-Based Deep Space Navigation Network

NASA Technical Reports Server (NTRS)

Anzalone, Evan J.; Chuang, C. H.

2012-01-01

As the need grows for increased autonomy and position knowledge accuracy to support missions beyond Earth orbit, engineers must push and develop more advanced navigation sensors and systems that operate independent of Earth-based analysis and processing. Several spacecraft are approaching this problem using inter-spacecraft radiometric tracking and onboard autonomous optical navigation methods. This paper proposes an alternative implementation to aid in spacecraft position fixing. The proposed method Network-Based Navigation technique takes advantage of the communication data being sent between spacecraft and between spacecraft and ground control to embed navigation information. The navigation system uses these packets to provide navigation estimates to an onboard navigation filter to augment traditional ground-based radiometric tracking techniques. As opposed to using digital signal measurements to capture inherent information of the transmitted signal itself, this method relies on the embedded navigation packet headers to calculate a navigation estimate. This method is heavily dependent on clock accuracy and the initial results show the promising performance of a notional system.

Mobile User Objective System (MUOS)

DTIC Science & Technology

2013-12-01

system capacity of the current UHF Follow-On ( UFO ) constellation. MUOS includes the satellite constellation, a ground control and network management...terminals able to support the MUOS CAI. Each MUOS satellite carries a legacy payload similar to that flown on UFO -11. These legacy payloads will...Antecedent Information: The antecedent system to MUOS was the Ultra High Frequency (UHF) Follow-on ( UFO ) satellite communications program. Comparisons of O

Inhibition of HSP70 and a Collagen-Specific Molecular Chaperone (HSP47) Expression in Rat Osteoblasts by Microgravity

NASA Technical Reports Server (NTRS)

Kumei, Yasuhiro; Morita, Sadao; Shimokawa, Hitoyata; Ohya, Kei'ichi; Akiyama, Hideo; Hirano, Masahiko; Sams, Clarence F.; Whitson, Peggy A.

2003-01-01

Rat osteoblasts were cultured aboard a space shuttle for 4 or 5 days. Cells were exposed to 1alpha, 25 dihydroxyvitamin D(3) during the last 20 h and then solubilized by guanidine solution. The mRNA levels for molecular chaperones were analyzed by semi-quantitative RT-PCR. ELISA was used to quantify TGF-beta1 in the conditioned medium. The HSP70 mRNA levels in the flight cultures were almost completely suppressed, as compared to the ground (1 x g) controls. The inducible HSP70 is known as the major heat shock protein that prevents stress-induced apoptosis. The mean mRNA levels for the constitutive HSC73 in the flight cultures were reduced to 69%, approximately 60% of the ground controls. HSC73 is reported to prevent the pathological state that is induced by disruption of microtubule network. The mean HSP47 mRNA levels in the flight cultures were decreased to 50% and 19% of the ground controls on the 4th and 5th days. Concomitantly, the concentration of TGF-beta1 in the conditioned medium of the flight cultures was reduced to 37% and 19% of the ground controls on the 4th and 5th days. HSP47 is the collagen-specific molecular chaperone that controls collagen processing and quality and is regulated by TGF-beta1. Microgravity differentially modulated the expression of molecular chaperones in osteoblasts, which might be involved in induction and/or prevention of osteopenia in space.

Secure real-time wireless video streaming in the aeronautical telecommunications network

NASA Astrophysics Data System (ADS)

Czernik, Pawel; Olszyna, Jakub

2010-09-01

As Air Traffic Control Systems move from a voice only environment to one in which clearances are issued via data link, there is a risk that an unauthorized entity may attempt to masquerade as either the pilot or controller. In order to protect against this and related attacks, air-ground communications must be secured. The challenge is to add security in an environment in which bandwidth is limited. The Aeronautical Telecommunications Network (ATN) is an enabling digital network communications technology that addresses capacity and efficiency issues associated with current aeronautical voice communication systems. Equally important, the ATN facilitates migration to free flight, where direct computer-to-computer communication will automate air traffic management, minimize controller and pilot workload, and improve overall aircraft routing efficiency. Protecting ATN communications is critical since safety-of-flight is seriously affected if an unauthorized entity, a hacker for example, is able to penetrate an otherwise reliable communications system and accidentally or maliciously introduce erroneous information that jeopardizes the overall safety and integrity of a given airspace. However, an ATN security implementation must address the challenges associated with aircraft mobility, limited bandwidth communication channels, and uninterrupted operation across organizational and geopolitical boundaries. This paper provides a brief overview of the ATN, the ATN security concept, and begins a basic introduction to the relevant security concepts of security threats, security services and security mechanisms. Security mechanisms are further examined by presenting the fundamental building blocks of symmetric encipherment, asymmetric encipherment, and hash functions. The second part of this paper presents the project of cryptographiclly secure wireless communication between Unmanned Aerial Vehicles (UAV) and the ground station in the ATM system, based on the ARM9 processor development kid and Embedded Linux operation system.

Recent technical advances in general purpose mobile Satcom aviation terminals

NASA Technical Reports Server (NTRS)

Sydor, John T.

1990-01-01

A second general aviation amplitude companded single sideband (ACSSB) aeronautical terminal was developed for use with the Ontario Air Ambulance Service (OAAS). This terminal is designed to have automatic call set up and take down and to interface with the Public Service Telephone Network (PSTN) through a ground earth station hub controller. The terminal has integrated RF and microprocessor hardware which allows such functions as beam steering and automatic frequency control to be software controlled. The terminal uses a conformal patch array system to provide almost full azimuthal coverage. Antenna beam steering is executed without relying on aircraft supplied orientation information.

Visualizing and Integrating AFSCN Utilization into a Common Operational Picture

NASA Astrophysics Data System (ADS)

Hays, B.; Carlile, A.; Mitchell, T.

The Department of Defense (DoD) and the 50th Space Network Operations Group Studies and Analysis branch (50th SCS/SCXI), located at Schriever AFB Colorado, face the unique challenge of forecasting the expected near term and future utilization of the Air Force Satellite Control Network (AFSCN). The forecasting timeframe covers the planned load from the current date to ten years out. The various satellite missions, satellite requirements, orbital regions, and ground architecture dynamics provide the model inputs and constraints that are used in generating the forecasted load. The AFSCN is the largest network the Air Force uses to control satellites worldwide. Each day, network personnel perform over 500 scheduled events-from satellite maneuvers to critical data downloads. The Forecasting Objective is to provide leadership with the insights necessary to manage the network today and tomorrow. For both today's needs and future needs, SCXI develops AFSCN utilization forecasts to optimize the ground system's coverage and capacity to meet user satellite requirements. SCXI also performs satellite program specific studies to determine network support feasibility. STK and STK Scheduler form the core of the tools used by SCXI. To establish this tool suite, we had to evaluate, evolve, and validate both the COTS products and our own developed code and processes. This began with calibrating the network model to emulate the real life scheduling environment of the AFSCN. Multiple STK Scheduler optimizing (de-confliction) algorithms, including Multi-Pass, Sequential, Random, and Neural, were evaluated and adjusted to determine applicability to the model and the accuracy of the prediction. Additionally, the scheduling Figure of Merit (FOM), which permits custom weighting of various parameters, was analyzed and tested to achieve the most accurate real life result. With the inherent capabilities of STK and the ability to wrap and automate output, SCXI is now able to visually communicate satellite loads in a manner never seen before in AFSCN management meetings. Scenarios such as regional antenna load stress, satellite missed opportunities, and the overall network "big picture" can be visually displayed in 3D versus the textual and line graph methods used for many years. This is the first step towards an integrated space awareness picture with an operational focus. SCXI is working on taking the visual forecast concept farther and begin fusing multiple sources of data to build a 50 SW Common Operating Picture (COP). The vision is to integrate more effective orbital determination processes, resource outages, current and forecasted satellite mission requirements, and future architectural changes into a real-time visual status to enable quick and responsive decisions. This COP would be utilized in a Wing Operations Center to provide up to the minute network status on where satellites are, which ground resources are in contact with them, and what resources are down. The ability to quickly absorb and process this data will enhance decision analysis and save valuable time in both day to day operations and wartime scenarios.

ESOC - The satellite operation center of the European Space Agency

NASA Astrophysics Data System (ADS)

Dworak, H. P.

1980-04-01

The operation and individual functions of the European Space Operation Center (ESOC) that controls the flight of ESA satellites are presented. The main role of the ESOC is discussed and its division into three areas: telemetry, remote piloting, and tracking is outlined. Attention is given to the manipulation of experimental data collected on board the satellites as well as to the functions of the individual ground stations. A block diagram of the information flow to the Meteosat receiving station is presented along with the network outlay of data flow between the ground stations and the ESOC. Distribution of tasks between the ground operation manager, spacecraft operations manager, and flight dynamic software coordinator is discussed with reference to a mission team. A short description of the current missions including COS-B, GEOS-1 and 2, Meteosat, OTS, and ISEE-B is presented

Orion Navigation Sensitivities to Ground Station Infrastructure for Lunar Missions

NASA Technical Reports Server (NTRS)

Getchius, Joel; Kukitschek, Daniel; Crain, Timothy

2008-01-01

The Orion Crew Exploration Vehicle (CEV) will replace the Space Shuttle and serve as the next-generation spaceship to carry humans to the International Space Station and back to the Moon for the first time since the Apollo program. As in the Apollo and Space Shuttle programs, the Mission Control Navigation team will utilize radiometric measurements to determine the position and velocity of the CEV. In the case of lunar missions, the ground station infrastructure consisting of approximately twelve stations distributed about the Earth and known as the Apollo Manned Spaceflight Network, no longer exists. Therefore, additional tracking resources will have to be allocated or constructed to support mission operations for Orion lunar missions. This paper examines the sensitivity of Orion navigation for lunar missions to the number and distribution of tracking sites that form the ground station infrastructure.

Inter-Comparison of Lightning Trends from Ground-Based Networks During Severe Weather: Applications Toward GLM

NASA Technical Reports Server (NTRS)

Carey, Lawrence D.; Schultz, Chris J.; Petersen, Walter A.; Rudlosky, Scott D.; Bateman, Monte; Cecil, Daniel J.; Blakeslee, Richard J.; Goodman, Steven J.

2011-01-01

The planned GOES-R Geostationary Lightning Mapper (GLM) will provide total lightning data on the location and intensity of thunderstorms over a hemispheric spatial domain. Ongoing GOES-R research activities are demonstrating the utility of total flash rate trends for enhancing forecasting skill of severe storms. To date, GLM total lightning proxy trends have been well served by ground-based VHF systems such as the Northern Alabama Lightning Mapping Array (NALMA). The NALMA (and other similar networks in Washington DC and Oklahoma) provide high detection efficiency (> 90%) and location accuracy (< 1 km) observations of total lightning within about 150 km from network center. To expand GLM proxy applications for high impact convective weather (e.g., severe, aviation hazards), it is desirable to investigate the utility of additional sources of continuous lightning that can serve as suitable GLM proxy over large spatial scales (order 100 s to 1000 km or more), including typically data denied regions such as the oceans. Potential sources of GLM proxy include ground-based long-range (regional or global) VLF/LF lightning networks such as the relatively new Vaisala Global Lightning Dataset (GLD360) and Weatherbug Total Lightning Network (WTLN). Before using these data in GLM research applications, it is necessary to compare them with LMAs and well-quantified cloud-to-ground (CG) lightning networks, such as Vaisala s National Lightning Detection Network (NLDN), for assessment of total and CG lightning location accuracy, detection efficiency and flash rate trends. Preliminary inter-comparisons from these lightning networks during selected severe weather events will be presented and their implications discussed.

Unattended wireless proximity sensor networks for counterterrorism, force protection, littoral environments, PHM, and tamper monitoring ground applications

NASA Astrophysics Data System (ADS)

Forcier, Bob

2003-09-01

This paper describes a digital-ultrasonic ground network, which forms an unique "unattended mote sensor system" for monitoring the environment, personnel, facilities, vehicles, power generation systems or aircraft in Counter-Terrorism, Force Protection, Prognostic Health Monitoring (PHM) and other ground applications. Unattended wireless smart sensor/tags continuously monitor the environment and provide alerts upon changes or disruptions to the environment. These wireless smart sensor/tags are networked utilizing ultrasonic wireless motes, hybrid RF/Ultrasonic Network Nodes and Base Stations. The network is monitored continuously with a 24/7 remote and secure monitoring system. This system utilizes physical objects such as a vehicle"s structure or a building to provide the media for two way secure communication of key metrics and sensor data and eliminates the "blind spots" that are common in RF solutions because of structural elements of buildings, etc. The digital-ultrasonic sensors have networking capability and a 32-bit identifier, which provide a platform for a robust data acquisition (DAQ) for a large amount of sensors. In addition, the network applies a unique "signature" of the environment by comparing sensor-to-sensor data to pick up on minute changes, which would signal an invasion of unknown elements or signal a potential tampering in equipment or facilities. The system accommodates satellite and other secure network uplinks in either RF or UWB protocols. The wireless sensors can be dispersed by ground or air maneuvers. In addition, the sensors can be incorporated into the structure or surfaces of vehicles, buildings, or clothing of field personnel.

The ground truth about metadata and community detection in networks.

PubMed

Peel, Leto; Larremore, Daniel B; Clauset, Aaron

2017-05-01

Across many scientific domains, there is a common need to automatically extract a simplified view or coarse-graining of how a complex system's components interact. This general task is called community detection in networks and is analogous to searching for clusters in independent vector data. It is common to evaluate the performance of community detection algorithms by their ability to find so-called ground truth communities. This works well in synthetic networks with planted communities because these networks' links are formed explicitly based on those known communities. However, there are no planted communities in real-world networks. Instead, it is standard practice to treat some observed discrete-valued node attributes, or metadata, as ground truth. We show that metadata are not the same as ground truth and that treating them as such induces severe theoretical and practical problems. We prove that no algorithm can uniquely solve community detection, and we prove a general No Free Lunch theorem for community detection, which implies that there can be no algorithm that is optimal for all possible community detection tasks. However, community detection remains a powerful tool and node metadata still have value, so a careful exploration of their relationship with network structure can yield insights of genuine worth. We illustrate this point by introducing two statistical techniques that can quantify the relationship between metadata and community structure for a broad class of models. We demonstrate these techniques using both synthetic and real-world networks, and for multiple types of metadata and community structures.

Continuum mechanical model for cross-linked actin networks with contractile bundles

NASA Astrophysics Data System (ADS)

Ferreira, J. P. S.; Parente, M. P. L.; Natal Jorge, R. M.

2018-01-01

In the context of a mechanical approach to cell biology, there is a close relationship between cellular function and mechanical properties. In recent years, an increasing amount of attention has been given to the coupling between biochemical and mechanical signals by means of constitutive models. In particular, on the active contractility of the actin cytoskeleton. Given the importance of the actin contraction on the physiological functions, this study propose a constitutive model to describe how the filamentous network controls its mechanics actively. Embedded in a soft isotropic ground substance, the network behaves as a viscous mechanical continuum, comprised of isotropically distributed cross-linked actin filaments and actomyosin bundles. Trough virtual rheometry experiments, the present model relates the dynamics of the myosin motors with the network stiffness, which is to a large extent governed by the time-scale of the applied deformations/forces.

Display integration for ground combat vehicles

NASA Astrophysics Data System (ADS)

Busse, David J.

1998-09-01

The United States Army's requirement to employ high resolution target acquisition sensors and information warfare to increase its dominance over enemy forces has led to the need to integrate advanced display devices into ground combat vehicle crew stations. The Army's force structure require the integration of advanced displays on both existing and emerging ground combat vehicle systems. The fielding of second generation target acquisition sensors, color digital terrain maps and high volume digital command and control information networks on these platforms define display performance requirements. The greatest challenge facing the system integrator is the development and integration of advanced displays that meet operational, vehicle and human computer interface performance requirements for the ground combat vehicle fleet. The subject of this paper is to address those challenges: operational and vehicle performance, non-soldier centric crew station configurations, display performance limitations related to human computer interfaces and vehicle physical environments, display technology limitations and the Department of Defense (DOD) acquisition reform initiatives. How the ground combat vehicle Program Manager and system integrator are addressing these challenges are discussed through the integration of displays on fielded, current and future close combat vehicle applications.

OMI satellite observations of decadal changes in ground-level sulfur dioxide over North America

NASA Astrophysics Data System (ADS)

Kharol, Shailesh K.; McLinden, Chris A.; Sioris, Christopher E.; Shephard, Mark W.; Fioletov, Vitali; van Donkelaar, Aaron; Philip, Sajeev; Martin, Randall V.

2017-05-01

Sulfur dioxide (SO2) has a significant impact on the environment and human health. We estimated ground-level sulfur dioxide (SO2) concentrations from the Ozone Monitoring Instrument (OMI) using SO2 profiles from the Global Environmental Multi-scale - Modelling Air quality and CHemistry (GEM-MACH) model over North America for the period of 2005-2015. OMI-derived ground-level SO2 concentrations (r = 0. 61) and trends (r = 0. 74) correlated well with coincident in situ measurements from air quality networks over North America. We found a strong decreasing trend in coincidently sampled ground-level SO2 from OMI (-81 ± 19 %) and in situ measurements (-86 ± 13 %) over the eastern US for the period of 2005-2015, which reflects the implementation of stricter pollution control laws, including flue-gas desulfurization (FGD) devices in power plants. The spatially and temporally contiguous OMI-derived ground-level SO2 concentrations can be used to assess the impact of long-term exposure to SO2 on the health of humans and the environment.

Lateral Information Processing by Spiking Neurons: A Theoretical Model of the Neural Correlate of Consciousness

PubMed Central

Ebner, Marc; Hameroff, Stuart

2011-01-01

Cognitive brain functions, for example, sensory perception, motor control and learning, are understood as computation by axonal-dendritic chemical synapses in networks of integrate-and-fire neurons. Cognitive brain functions may occur either consciously or nonconsciously (on “autopilot”). Conscious cognition is marked by gamma synchrony EEG, mediated largely by dendritic-dendritic gap junctions, sideways connections in input/integration layers. Gap-junction-connected neurons define a sub-network within a larger neural network. A theoretical model (the “conscious pilot”) suggests that as gap junctions open and close, a gamma-synchronized subnetwork, or zone moves through the brain as an executive agent, converting nonconscious “auto-pilot” cognition to consciousness, and enhancing computation by coherent processing and collective integration. In this study we implemented sideways “gap junctions” in a single-layer artificial neural network to perform figure/ground separation. The set of neurons connected through gap junctions form a reconfigurable resistive grid or sub-network zone. In the model, outgoing spikes are temporally integrated and spatially averaged using the fixed resistive grid set up by neurons of similar function which are connected through gap-junctions. This spatial average, essentially a feedback signal from the neuron's output, determines whether particular gap junctions between neurons will open or close. Neurons connected through open gap junctions synchronize their output spikes. We have tested our gap-junction-defined sub-network in a one-layer neural network on artificial retinal inputs using real-world images. Our system is able to perform figure/ground separation where the laterally connected sub-network of neurons represents a perceived object. Even though we only show results for visual stimuli, our approach should generalize to other modalities. The system demonstrates a moving sub-network zone of synchrony, within which the contents of perception are represented and contained. This mobile zone can be viewed as a model of the neural correlate of consciousness in the brain. PMID:22046178

Lateral information processing by spiking neurons: a theoretical model of the neural correlate of consciousness.

PubMed

Ebner, Marc; Hameroff, Stuart

2011-01-01

Cognitive brain functions, for example, sensory perception, motor control and learning, are understood as computation by axonal-dendritic chemical synapses in networks of integrate-and-fire neurons. Cognitive brain functions may occur either consciously or nonconsciously (on "autopilot"). Conscious cognition is marked by gamma synchrony EEG, mediated largely by dendritic-dendritic gap junctions, sideways connections in input/integration layers. Gap-junction-connected neurons define a sub-network within a larger neural network. A theoretical model (the "conscious pilot") suggests that as gap junctions open and close, a gamma-synchronized subnetwork, or zone moves through the brain as an executive agent, converting nonconscious "auto-pilot" cognition to consciousness, and enhancing computation by coherent processing and collective integration. In this study we implemented sideways "gap junctions" in a single-layer artificial neural network to perform figure/ground separation. The set of neurons connected through gap junctions form a reconfigurable resistive grid or sub-network zone. In the model, outgoing spikes are temporally integrated and spatially averaged using the fixed resistive grid set up by neurons of similar function which are connected through gap-junctions. This spatial average, essentially a feedback signal from the neuron's output, determines whether particular gap junctions between neurons will open or close. Neurons connected through open gap junctions synchronize their output spikes. We have tested our gap-junction-defined sub-network in a one-layer neural network on artificial retinal inputs using real-world images. Our system is able to perform figure/ground separation where the laterally connected sub-network of neurons represents a perceived object. Even though we only show results for visual stimuli, our approach should generalize to other modalities. The system demonstrates a moving sub-network zone of synchrony, within which the contents of perception are represented and contained. This mobile zone can be viewed as a model of the neural correlate of consciousness in the brain.

Networked simulation for team training of Space Station astronauts, ground controllers, and scientists - A training and development environment

NASA Technical Reports Server (NTRS)

Hajare, Ankur R.; Wick, Daniel T.; Bovenzi, James J.

1991-01-01

The purpose of this paper is to describe plans for the Space Station Training Facility (SSTF) which has been designed to meet the envisioned training needs for Space Station Freedom. To meet these needs, the SSTF will integrate networked simulators with real-world systems in five training modes: Stand-Alone, Combined, Joint-Combined, Integrated, and Joint-Integrated. This paper describes the five training modes within the context of three training scenaries. In addition, this paper describes an authoring system which will support the rapid integration of new real-world system changes in the Space Station Freedom Program.

Analysis of the error of the developed method of determination the active conductivity reducing the insulation level between one phase of the network and ground, and insulation parameters in a non-symmetric network with isolated neutral with voltage above 1000 V

NASA Astrophysics Data System (ADS)

Utegulov, B. B.

2018-02-01

In the work the study of the developed method was carried out for reliability by analyzing the error in indirect determination of the insulation parameters in an asymmetric network with an isolated neutral voltage above 1000 V. The conducted studies of the random relative mean square errors show that the accuracy of indirect measurements in the developed method can be effectively regulated not only by selecting a capacitive additional conductivity, which are connected between phases of the electrical network and the ground, but also by the selection of measuring instruments according to the accuracy class. When choosing meters with accuracy class of 0.5 with the correct selection of capacitive additional conductivity that are connected between the phases of the electrical network and the ground, the errors in measuring the insulation parameters will not exceed 10%.

Impact of a Ground Network of Miniaturized Laser Heterodyne Radiometers (mini-LHRs) on Global Carbon Flux Estimates

NASA Astrophysics Data System (ADS)

DiGregorio, A.; Wilson, E. L.; Palmer, P. I.; Mao, J.; Feng, L.

2017-12-01

We present the simulated impact of a small (50 instrument) ground network of NASA Goddard Space Flight Center's miniaturized laser heterodyne radiometer (mini-LHR), a small, low cost ( 50k), portable, and high precision CH4 and CO2 measuring instrument. Partnered with AERONET as a non-intrusive accessory, the mini-LHR is able to leverage the 500+ instrument AERONET network for rapid network deployment and testing, and simultaneously retrieve co-located aerosol data, an important input for sattelite measurements. This observing systems simulation experiment (OSSE) uses the 3-D GEOS-Chem chemistry transport model and 50 strategically selected sites to model flux estimate uncertainty reduction of both TCCON and mini-LHR instruments. We found that 50 mini-LHR sites are capable of improving global uncertainty by up to 70%, with local improvements in the Southern Hemisphere reaching to 90%. Our studies show that addition of the mini-LHR to current ground networks will play a major role in reduction of global carbon flux uncertainty.

Distrubtion Tolerant Network Technology Flight Validation Report: DINET

NASA Technical Reports Server (NTRS)

Jones, Ross M.

2009-01-01

In October and November of 2008, the Jet Propulsion Laboratory installed and tested essential elements of Delay/Disruption Tolerant Networking (DTN) technology on the Deep Impact spacecraft. This experiment, called Deep Impact Network Experiment (DINET), was performed in close cooperation with the EPOXI project which has responsibility for the spacecraft. During DINET some 300 images were transmitted from the JPL nodes to the spacecraft. Then, they were automatically forwarded from the spacecraft back to the JPL nodes, exercising DTN's bundle origination, transmission, acquisition, dynamic route computation, congestion control, prioritization, custody transfer, and automatic retransmission procedures, both on the spacecraft and on the ground, over a period of 27 days. All transmitted bundles were successfully received, without corruption. The DINET experiment demonstrated DTN readiness for operational use in space missions.

Distribution Tolerant Network Technology Flight Validation Report: DINET

NASA Technical Reports Server (NTRS)

Jones, Ross M.

2009-01-01

In October and November of 2008, the Jet Propulsion Laboratory installed and tested essential elements of Delay/Disruption Tolerant Networking (DTN) technology on the Deep Impact spacecraft. This experiment, called Deep Impact Network Experiment (DINET), was performed in close cooperation with the EPOXI project which has responsibility for the spacecraft. During DINET some 300 images were transmitted from the JPL nodes to the spacecraft. Then, they were automatically forwarded from the spacecraft back to the JPL nodes, exercising DTN's bundle origination, transmission, acquisition, dynamic route computation, congestion control, prioritization, custody transfer, and automatic retransmission procedures, both on the spacecraft and on the ground, over a period of 27 days. All transmitted bundles were successfully received, without corruption. The DINET experiment demonstrated DTN readiness for operational use in space missions.

Heterogeneous Multi-Robot System for Mapping Environmental Variables of Greenhouses

PubMed Central

Roldán, Juan Jesús; Garcia-Aunon, Pablo; Garzón, Mario; de León, Jorge; del Cerro, Jaime; Barrientos, Antonio

2016-01-01

The productivity of greenhouses highly depends on the environmental conditions of crops, such as temperature and humidity. The control and monitoring might need large sensor networks, and as a consequence, mobile sensory systems might be a more suitable solution. This paper describes the application of a heterogeneous robot team to monitor environmental variables of greenhouses. The multi-robot system includes both ground and aerial vehicles, looking to provide flexibility and improve performance. The multi-robot sensory system measures the temperature, humidity, luminosity and carbon dioxide concentration in the ground and at different heights. Nevertheless, these measurements can be complemented with other ones (e.g., the concentration of various gases or images of crops) without a considerable effort. Additionally, this work addresses some relevant challenges of multi-robot sensory systems, such as the mission planning and task allocation, the guidance, navigation and control of robots in greenhouses and the coordination among ground and aerial vehicles. This work has an eminently practical approach, and therefore, the system has been extensively tested both in simulations and field experiments. PMID:27376297

A performance study of unmanned aerial vehicle-based sensor networks under cyber attack

NASA Astrophysics Data System (ADS)

Puchaty, Ethan M.

In UAV-based sensor networks, an emerging area of interest is the performance of these networks under cyber attack. This study seeks to evaluate the performance trade-offs from a System-of-Systems (SoS) perspective between various UAV communications architecture options in the context two missions: tracking ballistic missiles and tracking insurgents. An agent-based discrete event simulation is used to model a sensor communication network consisting of UAVs, military communications satellites, ground relay stations, and a mission control center. Network susceptibility to cyber attack is modeled with probabilistic failures and induced data variability, with performance metrics focusing on information availability, latency, and trustworthiness. Results demonstrated that using UAVs as routers increased network availability with a minimal latency penalty and communications satellite networks were best for long distance operations. Redundancy in the number of links between communication nodes helped mitigate cyber-caused link failures and add robustness in cases of induced data variability by an adversary. However, when failures were not independent, redundancy and UAV routing were detrimental in some cases to network performance. Sensitivity studies indicated that long cyber-caused downtimes and increasing failure dependencies resulted in build-ups of failures and caused significant degradations in network performance.

Strong systematicity through sensorimotor conceptual grounding: an unsupervised, developmental approach to connectionist sentence processing

NASA Astrophysics Data System (ADS)

Jansen, Peter A.; Watter, Scott

2012-03-01

Connectionist language modelling typically has difficulty with syntactic systematicity, or the ability to generalise language learning to untrained sentences. This work develops an unsupervised connectionist model of infant grammar learning. Following the semantic boostrapping hypothesis, the network distils word category using a developmentally plausible infant-scale database of grounded sensorimotor conceptual representations, as well as a biologically plausible semantic co-occurrence activation function. The network then uses this knowledge to acquire an early benchmark clausal grammar using correlational learning, and further acquires separate conceptual and grammatical category representations. The network displays strongly systematic behaviour indicative of the general acquisition of the combinatorial systematicity present in the grounded infant-scale language stream, outperforms previous contemporary models that contain primarily noun and verb word categories, and successfully generalises broadly to novel untrained sensorimotor grounded sentences composed of unfamiliar nouns and verbs. Limitations as well as implications to later grammar learning are discussed.

Urban MEMS based seismic network for post-earthquakes rapid disaster assessment

NASA Astrophysics Data System (ADS)

D'Alessandro, Antonino; Luzio, Dario; D'Anna, Giuseppe

2014-05-01

Life losses following disastrous earthquake depends mainly by the building vulnerability, intensity of shaking and timeliness of rescue operations. In recent decades, the increase in population and industrial density has significantly increased the exposure to earthquakes of urban areas. The potential impact of a strong earthquake on a town center can be reduced by timely and correct actions of the emergency management centers. A real time urban seismic network can drastically reduce casualties immediately following a strong earthquake, by timely providing information about the distribution of the ground shaking level. Emergency management centers, with functions in the immediate post-earthquake period, could be use this information to allocate and prioritize resources to minimize loss of human life. However, due to the high charges of the seismological instrumentation, the realization of an urban seismic network, which may allow reducing the rate of fatalities, has not been achieved. Recent technological developments in MEMS (Micro Electro-Mechanical Systems) technology could allow today the realization of a high-density urban seismic network for post-earthquakes rapid disaster assessment, suitable for the earthquake effects mitigation. In the 1990s, MEMS accelerometers revolutionized the automotive-airbag system industry and are today widely used in laptops, games controllers and mobile phones. Due to their great commercial successes, the research into and development of MEMS accelerometers are actively pursued around the world. Nowadays, the sensitivity and dynamics of these sensors are such to allow accurate recording of earthquakes with moderate to strong magnitude. Due to their low cost and small size, the MEMS accelerometers may be employed for the realization of high-density seismic networks. The MEMS accelerometers could be installed inside sensitive places (high vulnerability and exposure), such as schools, hospitals, public buildings and places of worship. The waveforms recorded could be promptly used to determine ground-shaking parameters, like peak ground acceleration/velocity/displacement, Arias and Housner intensity, that could be all used to create, few seconds after a strong earthquakes, shaking maps at urban scale. These shaking maps could allow to quickly identify areas of the town center that have had the greatest earthquake resentment. When a strong seismic event occur, the beginning of the ground motion observed at the site could be used to predict the ensuing ground motion at the same site and so to realize a short term earthquake early warning system. The data acquired after a moderate magnitude earthquake, would provide valuable information for the detail seismic microzonation of the area based on direct earthquake shaking observations rather than from a model-based or indirect methods. In this work, we evaluate the feasibility and effectiveness of such seismic network taking in to account both technological, scientific and economic issues. For this purpose, we have simulated the creation of a MEMS based urban seismic network in a medium size city. For the selected town, taking into account the instrumental specifics, the array geometry and the environmental noise, we investigated the ability of the planned network to detect and measure earthquakes of different magnitude generated from realistic near seismogentic sources.

Decadal-scale changes of nitrate in ground water of the United States, 1988-2004

USGS Publications Warehouse

Rupert, Michael G.

2008-01-01

This study evaluated decadal-scale changes of nitrate concentrations in groundwater samples collected by the USGS National Water-Quality Assessment Program from 495 wells in 24 well networks across the USA in predominantly agricultural areas. Each well network was sampled once during 1988-1995 and resampled once during 2000-2004. Statistical tests of decadal-scale changes of nitrate concentrations in water from all 495 wells combined indicate there is a significant increase in nitrate concentrations in the data set as a whole. Eight out of the 24 well networks, or about 33%, had significant changes of nitrate concentrations. Of the eight well networks with significant decadal-scale changes of nitrate, all except one, the Willamette Valley of Oregon, had increasing nitrate concentrations. Median nitrate concentrations of three of those eight well networks increased above the USEPA maximum contaminant level of 10 mg L-1. Nitrate in water from wells with reduced conditions had significantly smaller decadal-scale changes in nitrate concentrations than oxidized and mixed waters. A subset of wells had data on ground water recharge date; nitrate concentrations increased in response to the increase of N fertilizer use since about 1950. Determining ground water recharge dates is an important component of a ground water trends investigation because recharge dates provide a link between changes in ground water quality and changes in land-use practices. Copyright ?? 2008 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

Hierarchical neural network model of the visual system determining figure/ground relation

NASA Astrophysics Data System (ADS)

Kikuchi, Masayuki

2017-07-01

One of the most important functions of the visual perception in the brain is figure/ground interpretation from input images. Figural region in 2D image corresponding to object in 3D space are distinguished from background region extended behind the object. Previously the author proposed a neural network model of figure/ground separation constructed on the standpoint that local geometric features such as curvatures and outer angles at corners are extracted and propagated along input contour in a single layer network (Kikuchi & Akashi, 2001). However, such a processing principle has the defect that signal propagation requires manyiterations despite the fact that actual visual system determines figure/ground relation within the short period (Zhou et al., 2000). In order to attain speed-up for determining figure/ground, this study incorporates hierarchical architecture into the previous model. This study confirmed the effect of the hierarchization as for the computation time by simulation. As the number of layers increased, the required computation time reduced. However, such speed-up effect was saturatedas the layers increased to some extent. This study attempted to explain this saturation effect by the notion of average distance between vertices in the area of complex network, and succeeded to mimic the saturation effect by computer simulation.

Solar-Powered Airplane with Cameras and WLAN

NASA Technical Reports Server (NTRS)

Higgins, Robert G.; Dunagan, Steve E.; Sullivan, Don; Slye, Robert; Brass, James; Leung, Joe G.; Gallmeyer, Bruce; Aoyagi, Michio; Wei, Mei Y.; Herwitz, Stanley R.;

Development of a Ground Water Data Portal for Interoperable Data Exchange within the U.S. National Ground Water Monitoring Network and Beyond

NASA Astrophysics Data System (ADS)

Booth, N. L.; Brodaric, B.; Lucido, J. M.; Kuo, I.; Boisvert, E.; Cunningham, W. L.

2011-12-01

The need for a national groundwater monitoring network within the United States is profound and has been recognized by organizations outside government as a major data gap for managing ground-water resources. Our country's communities, industries, agriculture, energy production and critical ecosystems rely on water being available in adequate quantity and suitable quality. To meet this need the Subcommittee on Ground Water, established by the Federal Advisory Committee on Water Information, created a National Ground Water Monitoring Network (NGWMN) envisioned as a voluntary, integrated system of data collection, management and reporting that will provide the data needed to address present and future ground-water management questions raised by Congress, Federal, State and Tribal agencies and the public. The NGWMN Data Portal is the means by which policy makers, academics and the public will be able to access ground water data through one seamless web-based application from disparate data sources. Data systems in the United States exist at many organizational and geographic levels and differing vocabulary and data structures have prevented data sharing and reuse. The data portal will facilitate the retrieval of and access to groundwater data on an as-needed basis from multiple, dispersed data repositories allowing the data to continue to be housed and managed by the data provider while being accessible for the purposes of the national monitoring network. This work leverages Open Geospatial Consortium (OGC) data exchange standards and information models. To advance these standards for supporting the exchange of ground water information, an OGC Interoperability Experiment was organized among international participants from government, academia and the private sector. The experiment focused on ground water data exchange across the U.S. / Canadian border. WaterML2.0, an evolving international standard for water observations, encodes ground water levels and is exchanged using the OGC Sensor Observation Service (SOS) standard. Ground Water Markup Language (GWML) encodes well log, lithology and construction information and is exchanged using the OGC Web Feature Service (WFS) standard. Within the NGWMN Data Portal, data exchange between distributed data provider repositories is achieved through the use of these web services and a central mediation hub, which performs both format (syntactic) and nomenclature (semantic) mediation, conforming heterogeneous inputs into common standards-based outputs. Through these common standards, interoperability between the U.S. NGWMN and Canada's Groundwater Information Network (GIN) is achieved, advancing a ground water virtual observatory across North America.

In-Space Internet-Based Communications for Space Science Platforms Using Commercial Satellite Networks

NASA Technical Reports Server (NTRS)

Kerczewski, Robert J.; Bhasin, Kul B.; Fabian, Theodore P.; Griner, James H.; Kachmar, Brian A.; Richard, Alan M.

1999-01-01

The continuing technological advances in satellite communications and global networking have resulted in commercial systems that now can potentially provide capabilities for communications with space-based science platforms. This reduces the need for expensive government owned communications infrastructures to support space science missions while simultaneously making available better service to the end users. An interactive, high data rate Internet type connection through commercial space communications networks would enable authorized researchers anywhere to control space-based experiments in near real time and obtain experimental results immediately. A space based communications network architecture consisting of satellite constellations connecting orbiting space science platforms to ground users can be developed to provide this service. The unresolved technical issues presented by this scenario are the subject of research at NASA's Glenn Research Center in Cleveland, Ohio. Assessment of network architectures, identification of required new or improved technologies, and investigation of data communications protocols are being performed through testbed and satellite experiments and laboratory simulations.

IT Security Support for the Spaceport Command Control Systems Development Ground Support Development Operations

NASA Technical Reports Server (NTRS)

Branch, Drew A.

2014-01-01

Security is one of the most if not the most important areas today. After the several attacks on the United States, security everywhere has heightened from airports to the communication among the military branches legionnaires. With advanced persistent threats (APT's) on the rise following Stuxnet, government branches and agencies are required, more than ever, to follow several standards, policies and procedures to reduce the likelihood of a breach. Attack vectors today are very advanced and are going to continue to get more and more advanced as security controls advance. This creates a need for networks and systems to be in an updated and secured state in a launch control system environment. FISMA is a law that is mandated by the government to follow when government agencies secure networks and devices. My role on this project is to ensure network devices and systems are in compliance with NIST, as outlined in FISMA. I will achieve this by providing assistance with security plan documentation and collection, system hardware and software inventory, malicious code and malware scanning, and configuration of network devices i.e. routers and IDS's/IPS's. In addition, I will be completing security assessments on software and hardware, vulnerability assessments and reporting, and conducting patch management and risk assessments. A guideline that will help with compliance with NIST is the SANS Top 20 Critical Controls. SANS Top 20 Critical Controls as well as numerous security tools, security software and the conduction of research will be used to successfully complete the tasks given to me. This will ensure compliance with FISMA and NIST, secure systems and a secured network. By the end of this project, I hope to have carried out the tasks stated above as well as gain an immense knowledge about compliance, security tools, networks and network devices, as well as policies and procedures.

IT Security Support for the Spaceport Command Control Systems Development Ground Support Development Operations

NASA Technical Reports Server (NTRS)

Branch, Drew

2013-01-01

Security is one of the most if not the most important areas today. After the several attacks on the United States, security everywhere was heightened from Airports to the communication among the military branches legionnaires. With advanced persistent threats (APTs) on the rise following Stuxnet, government branches and agencies are required, more than ever, to follow several standards, policies and procedures to reduce the likelihood of a breach. Attack vectors today are very advanced and are going to continue to get more and more advanced as security controls advance. This creates a need for networks and systems to be in an updated and secured state in a launch control system environment. FISMA is a law that is mandated by the government to follow when government agencies secure networks and devices. My role on this project is to ensure network devices and systems are in compliance with NIST, as outlined in FISMA. I will achieve this by providing assistance with security plan documentation and collection, system hardware and software inventory, malicious code and malware scanning and configuration of network devices i.e. routers and IDSsIPSs. In addition I will be completing security assessments on software and hardware, vulnerability assessments and reporting, conducting patch management and risk assessments. A guideline that will help with compliance with NIST is the SANS Top 20 Critical Controls. SANS Top 20 Critical Controls as well as numerous security tools, security software and the conduction of research will be used to successfully complete the tasks given to me. This will ensure compliance with FISMA and NIST, secure systems and a secured network. By the end of this project, I hope to have carried out stated above as well as gain an immense knowledge about compliance, security tools, networks and network devices, policies and procedures.

Effects of space weather on high-latitude ground systems

NASA Astrophysics Data System (ADS)

Pirjola, Risto

Geomagnetically induced currents (GIC) in technological systems, such as power grids, pipelines, cables and railways, are a ground manifestation of space weather. The first GIC observations were already made in early telegraph equipment more than 150 years ago. In power networks, GIC may saturate transformers with possible harmful consequences extending even to a collapse of the whole system or to permanent damage of transformers. In pipelines, GIC and the associated pipe-to-soil voltages may enhance corrosion or disturb surveys associated with corrosion control. GIC are driven by the geoelectric field induced by a geomagnetic variation at the Earth’s surface. The electric and magnetic fields are primarily produced by ionospheric currents and secondarily affected by the ground conductivity. Of great importance is the auroral electrojet with other rapidly varying currents indicating that GIC are a particular high-latitude problem. In this paper, we summarize the GIC research done in Finland during about 25 years, and discuss the calculation of GIC in a given network. Special attention is paid to modelling a power system. It is shown that, when considering GIC at a site, it is usually sufficient to take account for a smaller grid in the vicinity of the particular site. Modelling GIC also provides a basis for developing forecasting and warning methods of GIC.

Autonomous Sensorweb Operations for Integrated Space, In-Situ Monitoring of Volcanic Activity

NASA Technical Reports Server (NTRS)

Chien, Steve A.; Doubleday, Joshua; Kedar, Sharon; Davies, Ashley G.; Lahusen, Richard; Song, Wenzhan; Shirazi, Behrooz; Mandl, Daniel; Frye, Stuart

2010-01-01

We have deployed and demonstrated operations of an integrated space in-situ sensorweb for monitoring volcanic activity. This sensorweb includes a network of ground sensors deployed to the Mount Saint Helens volcano as well as the Earth Observing One spacecraft. The ground operations and space operations are interlinked in that ground-based intelligent event detections can cause the space segment to acquire additional data via observation requests and space-based data acquisitions (thermal imagery) can trigger reconfigurations of the ground network to allocate increased bandwidth to areas of the network best situated to observe the activity. The space-based operations are enabled by an automated mission planning and tasking capability which utilizes several Opengeospatial Consortium (OGC) Sensorweb Enablement (SWE) standards which enable acquiring data, alerts, and tasking using web services. The ground-based segment also supports similar protocols to enable seamless tasking and data delivery. The space-based segment also supports onboard development of data products (thermal summary images indicating areas of activity, quicklook context images, and thermal activity alerts). These onboard developed products have reduced data volume (compared to the complete images) which enables them to be transmitted to the ground more rapidly in engineering channels.

System control of an autonomous planetary mobile spacecraft

NASA Technical Reports Server (NTRS)

Dias, William C.; Zimmerman, Barbara A.

1990-01-01

The goal is to suggest the scheduling and control functions necessary for accomplishing mission objectives of a fairly autonomous interplanetary mobile spacecraft, while maximizing reliability. Goals are to provide an extensible, reliable system conservative in its use of on-board resources, while getting full value from subsystem autonomy, and avoiding the lure of ground micromanagement. A functional layout consisting of four basic elements is proposed: GROUND and SYSTEM EXECUTIVE system functions and RESOURCE CONTROL and ACTIVITY MANAGER subsystem functions. The system executive includes six subfunctions: SYSTEM MANAGER, SYSTEM FAULT PROTECTION, PLANNER, SCHEDULE ADAPTER, EVENT MONITOR and RESOURCE MONITOR. The full configuration is needed for autonomous operation on Moon or Mars, whereas a reduced version without the planning, schedule adaption and event monitoring functions could be appropriate for lower-autonomy use on the Moon. An implementation concept is suggested which is conservative in use of system resources and consists of modules combined with a network communications fabric. A language concept termed a scheduling calculus for rapidly performing essential on-board schedule adaption functions is introduced.

SCOS 2: A distributed architecture for ground system control

NASA Astrophysics Data System (ADS)

Keyte, Karl P.

The current generation of spacecraft ground control systems in use at the European Space Agency/European Space Operations Centre (ESA/ESOC) is based on the SCOS 1. Such systems have become difficult to manage in both functional and financial terms. The next generation of spacecraft is demanding more flexibility in the use, configuration and distribution of control facilities as well as functional requirements capable of matching those being planned for future missions. SCOS 2 is more than a successor to SCOS 1. Many of the shortcomings of the existing system have been carefully analyzed by user and technical communities and a complete redesign was made. Different technologies were used in many areas including hardware platform, network architecture, user interfaces and implementation techniques, methodologies and language. As far as possible a flexible design approach has been made using popular industry standards to provide vendor independence in both hardware and software areas. This paper describes many of the new approaches made in the architectural design of the SCOS 2.

Summary appraisals of the Nation's ground-water resources; Alaska

USGS Publications Warehouse

Zenone, Chester; Anderson, Gary S.

1978-01-01

Present deficiencies in the ground-water information base are obvious limiting factors to ground-water development in Alaska. There is a need to extend the ground-water data-collection network and to pursue special research into the quantitative aspects of ground-water hydrology in cold regions, particularly the continuous permafrost zone.

Performance Evaluation of a Prototyped Wireless Ground Sensor Network

DTIC Science & Technology

2005-03-01

the network was capable of dynamic adaptation to failure and degradation. 14. SUBJECT TERMS: Wireless Sensor Network , Unmanned Sensor, Unattended...2 H. WIRELESS SENSOR NETWORKS .................................................................... 3...zation, and network traffic. The evaluated scenarios included outdoor, urban and indoor environments. The characteristics of wireless sensor networks , types

Shoran Photogrammetric Mapping Instructions

DTIC Science & Technology

1950-05-15

Armyoufi 16, t t! .: - ! ý 3ý,by The C raazdfrg Officer lngin~er Reserch aca Develolmnt Laboratories Prsperett by Archer M. WilsonL Photogrinmetrio, Brancoh...using agency. The Corps of EnizI.neers is rasponstbie for the final adjustment and analysis of completed control networks resulting from Shoran...path is greatest near the ground., but the path approaches a straight line at higher altitudles where atmosaleric pressure and moisture content become

Ground data systems resource allocation process

NASA Technical Reports Server (NTRS)

Berner, Carol A.; Durham, Ralph; Reilly, Norman B.

1989-01-01

The Ground Data Systems Resource Allocation Process at the Jet Propulsion Laboratory provides medium- and long-range planning for the use of Deep Space Network and Mission Control and Computing Center resources in support of NASA's deep space missions and Earth-based science. Resources consist of radio antenna complexes and associated data processing and control computer networks. A semi-automated system was developed that allows operations personnel to interactively generate, edit, and revise allocation plans spanning periods of up to ten years (as opposed to only two or three weeks under the manual system) based on the relative merit of mission events. It also enhances scientific data return. A software system known as the Resource Allocation and Planning Helper (RALPH) merges the conventional methods of operations research, rule-based knowledge engineering, and advanced data base structures. RALPH employs a generic, highly modular architecture capable of solving a wide variety of scheduling and resource sequencing problems. The rule-based RALPH system has saved significant labor in resource allocation. Its successful use affirms the importance of establishing and applying event priorities based on scientific merit, and the benefit of continuity in planning provided by knowledge-based engineering. The RALPH system exhibits a strong potential for minimizing development cycles of resource and payload planning systems throughout NASA and the private sector.

A deployment of broadband seismic stations in two deep gold mines, South Africa

USGS Publications Warehouse

McGarr, Arthur F.; Boettcher, Margaret S.; Fletcher, Jon Peter B.; Johnston, Malcolm J.; Durrheim, R.; Spottiswoode, S.; Milev, A.

2009-01-01

In-mine seismic networks throughout the TauTona and Mponeng gold mines provide precise locations and seismic source parameters of earthquakes. They also support small-scale experimental projects, including NELSAM (Natural Earthquake Laboratory in South African Mines), which is intended to record, at close hand, seismic rupture of a geologic fault that traverses the project region near the deepest part of TauTona. To resolve some questions regarding the in-mine and NELSAM networks, we deployed four portable broadband seismic stations at deep sites within TauTona and Mponeng for one week during September 2007 and recorded ground acceleration. Moderately large earthquakes within our temporary network were recorded with sufficiently high signal-to-noise that we were able to integrate the acceleration to ground velocity and displacement, from which moment tensors could be determined. We resolved the questions concerning the NELSAM and in-mine networks by using these moment tensors to calculate synthetic seismograms at various network recording sites for comparison with the ground motion recorded at the same locations. We also used the peak velocity of the S wave pulse, corrected for attenuation with distance, to estimate the maximum slip within the rupture zone of an earthquake. We then combined the maximum slip and seismic moment with results from laboratory friction experiments to estimate maximum slip rates within the same high-slip patches of the rupture zone. For the four largest earthquakes recorded within our network, all with magnitudes near 2, these inferred maximum slips range from 4 to 27 mm and the corresponding maximum slip rates range from 1 to 6 m/s. These results, in conjunction with information from previous ground motion studies, indicate that underground support should be capable of withstanding peak ground velocities of at least 5 m/s.

SPARTAN: a global network to evaluate and enhance satellite-based estimates of ground-level particulate matter for global health applications

NASA Astrophysics Data System (ADS)

Snider, G.; Weagle, C. L.; Martin, R. V.; van Donkelaar, A.; Conrad, K.; Cunningham, D.; Gordon, C.; Zwicker, M.; Akoshile, C.; Artaxo, P.; Anh, N. X.; Brook, J.; Dong, J.; Garland, R. M.; Greenwald, R.; Griffith, D.; He, K.; Holben, B. N.; Kahn, R.; Koren, I.; Lagrosas, N.; Lestari, P.; Ma, Z.; Vanderlei Martins, J.; Quel, E. J.; Rudich, Y.; Salam, A.; Tripathi, S. N.; Yu, C.; Zhang, Q.; Zhang, Y.; Brauer, M.; Cohen, A.; Gibson, M. D.; Liu, Y.

2015-01-01

Ground-based observations have insufficient spatial coverage to assess long-term human exposure to fine particulate matter (PM2.5) at the global scale. Satellite remote sensing offers a promising approach to provide information on both short- and long-term exposure to PM2.5 at local-to-global scales, but there are limitations and outstanding questions about the accuracy and precision with which ground-level aerosol mass concentrations can be inferred from satellite remote sensing alone. A key source of uncertainty is the global distribution of the relationship between annual average PM2.5 and discontinuous satellite observations of columnar aerosol optical depth (AOD). We have initiated a global network of ground-level monitoring stations designed to evaluate and enhance satellite remote sensing estimates for application in health-effects research and risk assessment. This Surface PARTiculate mAtter Network (SPARTAN) includes a global federation of ground-level monitors of hourly PM2.5 situated primarily in highly populated regions and collocated with existing ground-based sun photometers that measure AOD. The instruments, a three-wavelength nephelometer and impaction filter sampler for both PM2.5 and PM10, are highly autonomous. Hourly PM2.5 concentrations are inferred from the combination of weighed filters and nephelometer data. Data from existing networks were used to develop and evaluate network sampling characteristics. SPARTAN filters are analyzed for mass, black carbon, water-soluble ions, and metals. These measurements provide, in a variety of regions around the world, the key data required to evaluate and enhance satellite-based PM2.5 estimates used for assessing the health effects of aerosols. Mean PM2.5 concentrations across sites vary by more than 1 order of magnitude. Our initial measurements indicate that the ratio of AOD to ground-level PM2.5 is driven temporally and spatially by the vertical profile in aerosol scattering. Spatially this ratio is also strongly influenced by the mass scattering efficiency.

Ikhana: A NASA UAS Supporting Long Duration Earth Science Missions

NASA Technical Reports Server (NTRS)

Cobleigh, Brent R.

2006-01-01

NASA's Ikhana unmanned aerial vehicle (UAV) is a General Atomics MQ-9 Predator-B modified to support the conduct of Earth science missions for the NASA Science Mission Directorate through partnerships, other government agencies and universities. Ikhana, a Native American word meaning 'intelligence', can carry over 2000 lbs of atmospheric and remote sensing instruments in the payload bay and external pods. The aircraft is capable of mission durations in excess of 24 hours at altitudes above 40,000 ft. Redundant flight control, avionics, power, and network systems increase the system reliability and allow easier access to public airspace. The aircraft is remotely piloted from a mobile ground control station (GCS) using both C-band line-of-sight and Ku-band over-the-horizon satellite datalinks. NASA's GCS has been modified to support on-site science monitoring, or the downlink data can be networked to remote sites. All ground support systems are designed to be deployable to support global Eart science investigations. On-board support capabilities include an instrumentation system and an Airborne Research Test System (ARTS). The ARTS can host research algorithms that will autonomously command and control on-board sensors, perform sensor health monitoring, conduct data analysis, and request changes to the flight plan to maximize data collection. The ARTS also has the ability to host algorithms that will autonomously control the aircraft trajectory based on sensor needs, (e.g. precision trajectory for repeat pass interferometry) or to optimize mission objectives (e.g. search for specific atmospheric conditions). Standard on-board networks will collect science data for recording and for inclusion in the aircraft's high bandwidth downlink. The Ikhana project will complete GCS development, science support systems integration, external pod integration and flight clearance, and operations crew training in early 2007. A large-area remote sensing mission is currently scheduled for the Summer 2007.

A water-quality monitoring network for Vallecitos Valley, Alameda County, California

USGS Publications Warehouse

Farrar, C.D.

1980-01-01

A water-quality monitoring network is proposed to detect the presence of and trace the movement of radioisotopes in the hydrologic system in the vicinity of the Vallecitos Nuclear Center. The source of the radioisotopes is treated industrial wastewater from the Vallecitos Nuclear Center that is discharged into an unnamed tributary of Vallecitos Creek. The effluent infiltrates the alluvium along the stream course, percolates downward to the water table, and mixes with the native ground water in the subsurface. The average daily discharge of effluent to the hydrologic system in 1978 was about 100,000 gallons. In Vallecitos Valley, the Livermore Gravel and the overlying alluvium constitute the ground-water reservoir. There is no subsurface inflow from adjacent ground-water basins. Ground-water flow in the Vallecitos subbasin is toward the southwest.The proposed network consists of four surface-water sampling sites and six wells to sample the ground-water system. Samples collected monthly at each site and analyzed for tritium and for alpha, beta, and gamma radiation would provide adequate data for monitoring.

Use of NEXRAD radar-based observations for quality control of in-situ rain gauge measurements

NASA Astrophysics Data System (ADS)

Nelson, B. R.; Prat, O.; Leeper, R.

2017-12-01

Rain gauge quality control is an often over looked important step in the archive of historical precipitation estimates. We investigate the possibilities that exist for using ground based radar networks for quality control of rain gauge measurements. This process includes the point to pixel comparisons of the rain gauge measurements with NEXRAD observations. There are two NEXRAD based data sets used for reference; the NCEP stage IV and the NWS MRMS gridded data sets. The NCEP stage IV data set is available at 4km hourly for the period 2002-present and includes the radar-gauge bias adjusted precipitation estimate. The NWS MRMS data set includes several different variables such as reflectivity, radar-only estimates, precipitation flag, and radar-gauge bias adjusted precipitation estimates. The latter product provides for much more information to apply quality control such as identification of precipitation type, identification of storm type and Z-R relation. In addition, some of the variables are available at 5-minute scale. The rain gauge networks that are investigated are the Climate Reference Network (CRN), the Fischer-Porter Hourly Precipitation Database (HPD), and the Hydrometeorological Automated Data System (HADS). The CRN network is available at the 5-minute scale, the HPD network is available at the 15-minute and hourly scale, and HADS is available at the hourly scale. The varying scales present challenges for comparisons. However given the higher resolution radar-based products we identify an optimal combination of rain gauge observations that can be compared to the radar-based information. The quality control process focuses on identifying faulty gauges in direct comparison while a deeper investigation focuses on event-based differences from light rain to extreme storms.

A Fast Method for Embattling Optimization of Ground-Based Radar Surveillance Network

NASA Astrophysics Data System (ADS)

Jiang, H.; Cheng, H.; Zhang, Y.; Liu, J.

A growing number of space activities have created an orbital debris environment that poses increasing impact risks to existing space systems and human space flight. For the safety of in-orbit spacecraft, a lot of observation facilities are needed to catalog space objects, especially in low earth orbit. Surveillance of Low earth orbit objects are mainly rely on ground-based radar, due to the ability limitation of exist radar facilities, a large number of ground-based radar need to build in the next few years in order to meet the current space surveillance demands. How to optimize the embattling of ground-based radar surveillance network is a problem to need to be solved. The traditional method for embattling optimization of ground-based radar surveillance network is mainly through to the detection simulation of all possible stations with cataloged data, and makes a comprehensive comparative analysis of various simulation results with the combinational method, and then selects an optimal result as station layout scheme. This method is time consuming for single simulation and high computational complexity for the combinational analysis, when the number of stations increases, the complexity of optimization problem will be increased exponentially, and cannot be solved with traditional method. There is no better way to solve this problem till now. In this paper, target detection procedure was simplified. Firstly, the space coverage of ground-based radar was simplified, a space coverage projection model of radar facilities in different orbit altitudes was built; then a simplified objects cross the radar coverage model was established according to the characteristics of space objects orbit motion; after two steps simplification, the computational complexity of the target detection was greatly simplified, and simulation results shown the correctness of the simplified results. In addition, the detection areas of ground-based radar network can be easily computed with the simplified model, and then optimized the embattling of ground-based radar surveillance network with the artificial intelligent algorithm, which can greatly simplifies the computational complexities. Comparing with the traditional method, the proposed method greatly improved the computational efficiency.

Comparison of the KSC-ER Cloud-to-Ground Lightning Surveillance System (CGLSS) and the U.S. National Lightning Detection Network(TradeMark)(NLDN)

NASA Technical Reports Server (NTRS)

Ward, Jennifer G.; Cummins, Kenneth L.; Krider, E. Philip

2007-01-01

The NASA Kennedy Space Center (KSC) and Air Force Eastern Range (ER) use data from two cloud-to-ground lightning detection networks, CGLSS and NLDN, during ground and launch operations at the KSC-ER. For these applications, it is very important to understand the location accuracy and detection efficiency of each network near the KSC-ER. If a cloud-to-ground (CG) lightning strike is missed or mis-located by even a small amount, the result could have significant safety implications, require expensive retests, or create unnecessary delays or scrubs in launches. Therefore, it is important to understand the performance of each lightning detection system in considerable detail. To evaluate recent upgrades in the CGLSS sensors in 2000 and the entire NLDN in 2002- 2003, we have compared. measurements provided by these independent networks in the summers of 2005 and 2006. Our analyses have focused on the fraction of first strokes reported individually and in-common by each network (flash detection efficiency), the spatial separation between the strike points reported by both networks (relative location accuracy), and the values of the estimated peak current, Ip, reported by each network. The results within 100 km of the KSC-ER show that the networks produce very similar values of Ip (except for a small scaling difference) and that the relative location accuracy is consistent with model estimates that give median values of 200-300m for the CGLSS and 600-700m for the NLDN in the region of the KSC-ER. Because of differences in the network geometries and sensor gains, the NLDN does not report 10-20% of the flashes that have a low Ip (2 kA < |Ip| < 16 kA), both networks report 99 % of the flashes that have intermediate values of Ip (16< |Ip| < 50 kA), and the CGLSS fails to report 20-30% of the high-current events (|Ip| >=0 kA).

Artist concept of the STS-43 Tracking and Data Relay Satellite E (TDRS-E)

NASA Image and Video Library

1990-06-22

Artist concept shows the Tracking and Data Relay Satellite E (TDRS-E) augmenting a sophisticated TDRS system (TDRSS) communications network after deployment during STS-43 from Atlantis, Orbiter Vehicle (OV) 104. TDRS, built by TRW, will be placed in a geosynchronous orbit and after onorbit testing, which requires several weeks, will be designated TDRS-5. The communications satellite will replace TDRS-3 at 174 degrees West longitude. The backbone of NASA's space-to-ground communications, the TDRSs have increased NASA's ability to send and receive data to spacecraft in low-earth orbit to more than 85 percent of the time. Before TDRS, NASA relied solely on a system of ground stations that permitted communications only 15 percent of the time. Increased coverage has allowed onorbit repairs, live television broadcast from space and continuous dialogues between astronaut crews and ground control during critical periods such as Space Shuttle landings.

Research on key technology of space laser communication network

NASA Astrophysics Data System (ADS)

Chang, Chengwu; Huang, Huiming; Liu, Hongyang; Gao, Shenghua; Cheng, Liyu

2016-10-01

Since the 21st century, Spatial laser communication has made a breakthrough development. Europe, the United States, Japan and other space powers have carried out the test of spatial laser communication technology on-orbit, and put forward a series of plans. In 2011, China made the first technology demonstration of satellite-ground laser communication carried by HY-2 satellite. Nowadays, in order to improve the transmission rate of spatial network, the topic of spatial laser communication network is becoming a research hotspot at home and abroad. This thesis, from the basic problem of spatial laser communication network to solve, analyzes the main difference between spatial network and ground network, which draws forth the key technology of spatial laser communication backbone network, and systematically introduces our research on aggregation, addressing, architecture of spatial network. From the perspective of technology development status and trends, the thesis proposes the development route of spatial laser communication network in stages. So as to provide reference about the development of spatial laser communication network in China.

Integrated Operations Architecture Technology Assessment Study

NASA Technical Reports Server (NTRS)

2001-01-01

As part of NASA's Integrated Operations Architecture (IOA) Baseline, NASA will consolidate all communications operations. including ground-based, near-earth, and deep-space communications, into a single integrated network. This network will make maximum use of commercial equipment, services and standards. It will be an Internet Protocol (IP) based network. This study supports technology development planning for the IOA. The technical problems that may arise when LEO mission spacecraft interoperate with commercial satellite services were investigated. Commercial technology and services that could support the IOA were surveyed, and gaps in the capability of existing technology and techniques were identified. Recommendations were made on which gaps should be closed by means of NASA research and development funding. Several findings emerged from the interoperability assessment: in the NASA mission set, there is a preponderance of small. inexpensive, low data rate science missions; proposed commercial satellite communications services could potentially provide TDRSS-like data relay functions; and. IP and related protocols, such as TCP, require augmentation to operate in the mobile networking environment required by the space-to-ground portion of the IOA. Five case studies were performed in the technology assessment. Each case represented a realistic implementation of the near-earth portion of the IOA. The cases included the use of frequencies at L-band, Ka-band and the optical spectrum. The cases also represented both space relay architectures and direct-to-ground architectures. Some of the main recommendations resulting from the case studies are: select an architecture for the LEO/MEO communications network; pursue the development of a Ka-band space-qualified transmitter (and possibly a receiver), and a low-cost Ka-band ground terminal for a direct-to-ground network, pursue the development of an Inmarsat (L-band) space-qualified transceiver to implement a global, low data rate network for LEO/MEO, mission spacecraft; and, pursue developmental research for a miniaturized, high data rate optical transceiver.

Space Link Extension (SLE) Emulation for High-Throughput Network Communication

NASA Technical Reports Server (NTRS)

Murawski, Robert W.; Tchorowski, Nicole; Golden, Bert

2014-01-01

As the data rate requirements for space communications increases, significant stress is placed not only on the wireless satellite communication links, but also on the ground networks which forward data from end-users to remote ground stations. These wide area network (WAN) connections add delay and jitter to the end-to-end satellite communication link, effects which can have significant impacts on the wireless communication link. It is imperative that any ground communication protocol can react to these effects such that the ground network does not become a bottleneck in the communication path to the satellite. In this paper, we present our SCENIC Emulation Lab testbed which was developed to test the CCSDS SLE protocol implementations proposed for use on future NASA communication networks. Our results show that in the presence of realistic levels of network delay, high-throughput SLE communication links can experience significant data rate throttling. Based on our observations, we present some insight into why this data throttling happens, and trace the probable issue back to non-optimal blocking communication which is sup-ported by the CCSDS SLE API recommended practices. These issues were presented as well to the SLE implementation developers which, based on our reports, developed a new release for SLE which we show fixes the SLE blocking issue and greatly improves the protocol throughput. In this paper, we also discuss future developments for our end-to-end emulation lab and how these improvements can be used to develop and test future space communication technologies.

LCOGT Imaging Lab

NASA Astrophysics Data System (ADS)

Tufts, Joseph R.; Lobdill, Rich; Haldeman, Benjamin J.; Haynes, Rachel; Hawkins, Eric; Burleson, Ben; Jahng, David

2008-07-01

The Las Cumbres Observatory Global Telescope Network (LCOGT) is an ambitious project to build and operate, within 5 years, a worldwide robotic network of 50 0.4, 1, and 2 m telescopes sharing identical instrumentation and optimized for precision photometry of time-varying sources. The telescopes, instrumentation, and software are all developed in house with two 2 m telescopes already installed. The LCOGT Imaging Lab is responsible for assembly and characterization of the network's cameras and instrumentation. In addition to a fully equipped CNC machine shop, two electronics labs, and a future optics lab, the Imaging Lab is designed from the ground up to be a superb environment for bare detectors, precision filters, and assembled instruments. At the heart of the lab is an ISO class 5 cleanroom with full ionization. Surrounding this, the class 7 main lab houses equipment for detector characterization including QE and CTE, and equipment for measuring transmission and reflection of optics. Although the first science cameras installed, two TEC cooled e2v 42-40 deep depletion based units and two CryoTiger cooled Fairchild Imaging CCD486-BI based units, are from outside manufacturers, their 18 position filter wheels and the remainder of the network's science cameras, controllers, and instrumentation will be built in house. Currently being designed, the first generation LCOGT cameras for the network's 1 m telescopes use existing CCD486-BI devices and an in-house controller. Additionally, the controller uses digital signal processing to optimize readout noise vs. speed, and all instrumentation uses embedded microprocessors for communication over ethernet.

Guidance and control for unmanned ground vehicles

NASA Astrophysics Data System (ADS)

Bateman, Peter J.

1994-06-01

Techniques for the guidance, control, and navigation of unmanned ground vehicles are described in terms of the communication bandwidth requirements for driving and control of a vehicle remote from the human operator. Modes of operation are conveniently classified as conventional teleoperation, supervisory control, and fully autonomous control. The fundamental problem of maintaining a robust non-line-of-sight communications link between the human controller and the remote vehicle is discussed, as this provides the impetus for greater autonomy in the control system and the greatest scope for innovation. While supervisory control still requires the man to be providing the primary navigational intelligence, fully autonomous operation requires that mission navigation is provided solely by on-board machine intelligence. Methods directed at achieving this performance are described using various active and passive sensing of the terrain for route navigation and obstacle detection. Emphasis is given to TV imagery and signal processing techniques for image understanding. Reference is made to the limitations of current microprocessor technology and suitable computer architectures. Some of the more recent control techniques involve the use of neural networks, fuzzy logic, and data fusion and these are discussed in the context of road following and cross country navigation. Examples of autonomous vehicle testbeds operated at various laboratories around the world are given.

Evaluating data worth for ground-water management under uncertainty

USGS Publications Warehouse

Wagner, B.J.

1999-01-01

A decision framework is presented for assessing the value of ground-water sampling within the context of ground-water management under uncertainty. The framework couples two optimization models-a chance-constrained ground-water management model and an integer-programing sampling network design model-to identify optimal pumping and sampling strategies. The methodology consists of four steps: (1) The optimal ground-water management strategy for the present level of model uncertainty is determined using the chance-constrained management model; (2) for a specified data collection budget, the monitoring network design model identifies, prior to data collection, the sampling strategy that will minimize model uncertainty; (3) the optimal ground-water management strategy is recalculated on the basis of the projected model uncertainty after sampling; and (4) the worth of the monitoring strategy is assessed by comparing the value of the sample information-i.e., the projected reduction in management costs-with the cost of data collection. Steps 2-4 are repeated for a series of data collection budgets, producing a suite of management/monitoring alternatives, from which the best alternative can be selected. A hypothetical example demonstrates the methodology's ability to identify the ground-water sampling strategy with greatest net economic benefit for ground-water management.A decision framework is presented for assessing the value of ground-water sampling within the context of ground-water management under uncertainty. The framework couples two optimization models - a chance-constrained ground-water management model and an integer-programming sampling network design model - to identify optimal pumping and sampling strategies. The methodology consists of four steps: (1) The optimal ground-water management strategy for the present level of model uncertainty is determined using the chance-constrained management model; (2) for a specified data collection budget, the monitoring network design model identifies, prior to data collection, the sampling strategy that will minimize model uncertainty; (3) the optimal ground-water management strategy is recalculated on the basis of the projected model uncertainty after sampling; and (4) the worth of the monitoring strategy is assessed by comparing the value of the sample information - i.e., the projected reduction in management costs - with the cost of data collection. Steps 2-4 are repeated for a series of data collection budgets, producing a suite of management/monitoring alternatives, from which the best alternative can be selected. A hypothetical example demonstrates the methodology's ability to identify the ground-water sampling strategy with greatest net economic benefit for ground-water management.

Observation-well network for collection of ground-water level data in Massachusetts

USGS Publications Warehouse

Socolow, Roy S.

1994-01-01

Aquifers--water-bearing deposits of sand and gravel, glacial till, and fractured bedrock--provide an extensive and readily accessible ground-water supply in Massachusetts. Ground water affects our everyday lives, not just in terms of how much water is available, but also in terms of the position of ground-water levels in relation to land surface. Knowledge of ground-water levels is needed by Federal, State, and local agencies to help plan, manage, and protect ground-water supplies, and by private construction companies for site planning and evaluation. A primary part of the mission of the U.S. Geological Survey (USGS), Water Resources Division, is the systematic collection of ground-water, surface-water, and water-quality data. These data are needed to manage and protect the nation's water resources. The Massachusetts-Rhode Island District of the USGS, in cooperation with the Massachusetts Department of Environmental Management (DEM), Office of Water Resources, and county and town environmental agencies, has maintained a network of observation wells throughout the Commonwealth since the mid 1930's. The purpose of this network is to monitor seasonal and long-term changes in groundwater storage in different lithologic, topographic, and geographic settings. These data are analyzed to provide a monthly index of ground-water conditions to aid in water-resources management and planning, and to define long-term changes in water levels resulting from manmade stresses (such as pumping and construction-site drainage) and natural stresses (such as floods and droughts).

Unsupervised learning in persistent sensing for target recognition by wireless ad hoc networks of ground-based sensors

NASA Astrophysics Data System (ADS)

Hortos, William S.

2008-04-01

In previous work by the author, effective persistent and pervasive sensing for recognition and tracking of battlefield targets were seen to be achieved, using intelligent algorithms implemented by distributed mobile agents over a composite system of unmanned aerial vehicles (UAVs) for persistence and a wireless network of unattended ground sensors for pervasive coverage of the mission environment. While simulated performance results for the supervised algorithms of the composite system are shown to provide satisfactory target recognition over relatively brief periods of system operation, this performance can degrade by as much as 50% as target dynamics in the environment evolve beyond the period of system operation in which the training data are representative. To overcome this limitation, this paper applies the distributed approach using mobile agents to the network of ground-based wireless sensors alone, without the UAV subsystem, to provide persistent as well as pervasive sensing for target recognition and tracking. The supervised algorithms used in the earlier work are supplanted by unsupervised routines, including competitive-learning neural networks (CLNNs) and new versions of support vector machines (SVMs) for characterization of an unknown target environment. To capture the same physical phenomena from battlefield targets as the composite system, the suite of ground-based sensors can be expanded to include imaging and video capabilities. The spatial density of deployed sensor nodes is increased to allow more precise ground-based location and tracking of detected targets by active nodes. The "swarm" mobile agents enabling WSN intelligence are organized in a three processing stages: detection, recognition and sustained tracking of ground targets. Features formed from the compressed sensor data are down-selected according to an information-theoretic algorithm that reduces redundancy within the feature set, reducing the dimension of samples used in the target recognition and tracking routines. Target tracking is based on simplified versions of Kalman filtration. Accuracy of recognition and tracking of implemented versions of the proposed suite of unsupervised algorithms is somewhat degraded from the ideal. Target recognition and tracking by supervised routines and by unsupervised SVM and CLNN routines in the ground-based WSN is evaluated in simulations using published system values and sensor data from vehicular targets in ground-surveillance scenarios. Results are compared with previously published performance for the system of the ground-based sensor network (GSN) and UAV swarm.

Optimization and throughput estimation of optical ground networks for LEO-downlinks, GEO-feeder links and GEO-relays

NASA Astrophysics Data System (ADS)

Fuchs, Christian; Poulenard, Sylvain; Perlot, Nicolas; Riedi, Jerome; Perdigues, Josep

2017-02-01

Optical satellite communications play an increasingly important role in a number of space applications. However, if the system concept includes optical links to the surface of the Earth, the limited availability due to clouds and other atmospheric impacts need to be considered to give a reliable estimate of the system performance. An OGS network is required for increasing the availability to acceptable figures. In order to realistically estimate the performance and achievable throughput in various scenarios, a simulation tool has been developed under ESA contract. The tool is based on a database of 5 years of cloud data with global coverage and can thus easily simulate different optical ground station network topologies for LEO- and GEO-to-ground links. Further parameters, like e.g. limited availability due to sun blinding and atmospheric turbulence, are considered as well. This paper gives an overview about the simulation tool, the cloud database, as well as the modelling behind the simulation scheme. Several scenarios have been investigated: LEO-to-ground links, GEO feeder links, and GEO relay links. The key results of the optical ground station network optimization and throughput estimations will be presented. The implications of key technical parameters, as e.g. memory size aboard the satellite, will be discussed. Finally, potential system designs for LEO- and GEO-systems will be presented.

Functional connectivity analysis in resting state fMRI with echo-state networks and non-metric clustering for network structure recovery

NASA Astrophysics Data System (ADS)

Wismüller, Axel; DSouza, Adora M.; Abidin, Anas Z.; Wang, Xixi; Hobbs, Susan K.; Nagarajan, Mahesh B.

2015-03-01

Echo state networks (ESN) are recurrent neural networks where the hidden layer is replaced with a fixed reservoir of neurons. Unlike feed-forward networks, neuron training in ESN is restricted to the output neurons alone thereby providing a computational advantage. We demonstrate the use of such ESNs in our mutual connectivity analysis (MCA) framework for recovering the primary motor cortex network associated with hand movement from resting state functional MRI (fMRI) data. Such a framework consists of two steps - (1) defining a pair-wise affinity matrix between different pixel time series within the brain to characterize network activity and (2) recovering network components from the affinity matrix with non-metric clustering. Here, ESNs are used to evaluate pair-wise cross-estimation performance between pixel time series to create the affinity matrix, which is subsequently subject to non-metric clustering with the Louvain method. For comparison, the ground truth of the motor cortex network structure is established with a task-based fMRI sequence. Overlap between the primary motor cortex network recovered with our model free MCA approach and the ground truth was measured with the Dice coefficient. Our results show that network recovery with our proposed MCA approach is in close agreement with the ground truth. Such network recovery is achieved without requiring low-pass filtering of the time series ensembles prior to analysis, an fMRI preprocessing step that has courted controversy in recent years. Thus, we conclude our MCA framework can allow recovery and visualization of the underlying functionally connected networks in the brain on resting state fMRI.

Annual Report to Congress: Military and Security Developments Involving the Peoples Republic of China 2016

DTIC Science & Technology

2016-04-26

control. Military discipline inspectors have targeted individual power networks and sectors historically prone to corruption, and the PLA is also...Other disputed areas include the Luconia Shoals, Reed Bank , and the Paracel Islands. The Luconia Shoals are disputed by China and Malaysia and...may contain extensive oil and natural gas reserves, as well as productive fishing grounds. Reed Bank is claimed by both China and the Philippines

Statistical Analysis of Wireless Networks: Predicting Performance in Multiple Environments

DTIC Science & Technology

2006-06-01

The demonstration planned for May 2006 is an air, ground, and water- based scenario, occurring just north of Chiang Mai , Thailand. The scenario...will be fused, displayed, and distributed in real-time to local ( Chiang Mai ), theater (Bangkok), and global (Alameda, California) command and control...COASTS 2006 TOPOLOGY The 2006 version of the COASTS project occurred just north of Chiang Mai , Thailand, at the Mae Ngat Dam. COTS systems were

From Fog to Friction: The Impact of Network-Enabled Command and Control on Operational Leadership

DTIC Science & Technology

2012-05-04

Highway, Suite 1204, Arlington, VA 22202-4302, and to the Office of Management and Budget, Paperwork Reduction Project (0704-0188) Washington, DC...decision-making of operational commanders, affecting their ability to manage the operational level of war. An increasing reliance on NEC2 has...picture (COP) provides the operational commander the ability to coordinate and manage a truly joint force. During OIF, ground forces under attack had

Future large broadband switched satellite communications networks

NASA Technical Reports Server (NTRS)

Staelin, D. H.; Harvey, R. R.

1979-01-01

Critical technical, market, and policy issues relevant to future large broadband switched satellite networks are summarized. Our market projections for the period 1980 to 2000 are compared. Clusters of switched satellites, in lieu of large platforms, etc., are shown to have significant advantages. Analysis of an optimum terrestrial network architecture suggests the proper densities of ground stations and that link reliabilities 99.99% may entail less than a 10% cost premium for diversity protection at 20/30 GHz. These analyses suggest that system costs increase as the 0.6 power of traffic. Cost estimates for nominal 20/30 GHz satellite and ground facilities suggest optimum system configurations might employ satellites with 285 beams, multiple TDMA bands each carrying 256 Mbps, and 16 ft ground station antennas. A nominal development program is outlined.

Device for limiting single phase ground fault of mining machines

NASA Astrophysics Data System (ADS)

Fediuk, R. S.; Stoyushko, N. Yu; Yevdokimova, Yu G.; Smoliakov, A. K.; Batarshin, V. O.; Timokhin, R. A.

2017-10-01

The paper shows the reasons and consequences of the single-phase ground fault. With all the variety of devices for limiting the current single-phase ground fault, it was found that the most effective are Peterson coils having different switching circuits. Measuring of the capacity of the network is of great importance in this case, a number of options capacitance measurement are presented. A closer look is taken at the device for limiting the current of single-phase short circuit, developed in the Far Eastern Federal University under the direction of Dr. G.E. Kuvshinov. The calculation of single-phase short-circuit currents in the electrical network, without compensation and with compensation of capacitive current is carried out. Simulation of a single-phase circuit in a network with the proposed device is conducted.

Description of the SSF PMAD DC testbed control system data acquisition function

NASA Technical Reports Server (NTRS)

Baez, Anastacio N.; Mackin, Michael; Wright, Theodore

1992-01-01

The NASA LeRC in Cleveland, Ohio has completed the development and integration of a Power Management and Distribution (PMAD) DC Testbed. This testbed is a reduced scale representation of the end to end, sources to loads, Space Station Freedom Electrical Power System (SSF EPS). This unique facility is being used to demonstrate DC power generation and distribution, power management and control, and system operation techniques considered to be prime candidates for the Space Station Freedom. A key capability of the testbed is its ability to be configured to address system level issues in support of critical SSF program design milestones. Electrical power system control and operation issues like source control, source regulation, system fault protection, end-to-end system stability, health monitoring, resource allocation, and resource management are being evaluated in the testbed. The SSF EPS control functional allocation between on-board computers and ground based systems is evolving. Initially, ground based systems will perform the bulk of power system control and operation. The EPS control system is required to continuously monitor and determine the current state of the power system. The DC Testbed Control System consists of standard controllers arranged in a hierarchical and distributed architecture. These controllers provide all the monitoring and control functions for the DC Testbed Electrical Power System. Higher level controllers include the Power Management Controller, Load Management Controller, Operator Interface System, and a network of computer systems that perform some of the SSF Ground based Control Center Operation. The lower level controllers include Main Bus Switch Controllers and Photovoltaic Controllers. Power system status information is periodically provided to the higher level controllers to perform system control and operation. The data acquisition function of the control system is distributed among the various levels of the hierarchy. Data requirements are dictated by the control system algorithms being implemented at each level. A functional description of the various levels of the testbed control system architecture, the data acquisition function, and the status of its implementationis presented.

Satellite ATM Networks: Architectures and Guidelines Developed

NASA Technical Reports Server (NTRS)

vonDeak, Thomas C.; Yegendu, Ferit

1999-01-01

An important element of satellite-supported asynchronous transfer mode (ATM) networking will involve support for the routing and rerouting of active connections. Work published under the auspices of the Telecommunications Industry Association (http://www.tiaonline.org), describes basic architectures and routing protocol issues for satellite ATM (SATATM) networks. The architectures and issues identified will serve as a basis for further development of technical specifications for these SATATM networks. Three ATM network architectures for bent pipe satellites and three ATM network architectures for satellites with onboard ATM switches were developed. The architectures differ from one another in terms of required level of mobility, supported data rates, supported terrestrial interfaces, and onboard processing and switching requirements. The documentation addresses low-, middle-, and geosynchronous-Earth-orbit satellite configurations. The satellite environment may require real-time routing to support the mobility of end devices and nodes of the ATM network itself. This requires the network to be able to reroute active circuits in real time. In addition to supporting mobility, rerouting can also be used to (1) optimize network routing, (2) respond to changing quality-of-service requirements, and (3) provide a fault tolerance mechanism. Traffic management and control functions are necessary in ATM to ensure that the quality-of-service requirements associated with each connection are not violated and also to provide flow and congestion control functions. Functions related to traffic management were identified and described. Most of these traffic management functions will be supported by on-ground ATM switches, but in a hybrid terrestrial-satellite ATM network, some of the traffic management functions may have to be supported by the onboard satellite ATM switch. Future work is planned to examine the tradeoffs of placing traffic management functions onboard a satellite as opposed to implementing those functions at the Earth station components.

In-Space Networking on NASA's SCAN Testbed

NASA Technical Reports Server (NTRS)

Brooks, David E.; Eddy, Wesley M.; Clark, Gilbert J.; Johnson, Sandra K.

2016-01-01

The NASA Space Communications and Navigation (SCaN) Testbed, an external payload onboard the International Space Station, is equipped with three software defined radios and a flight computer for supporting in-space communication research. New technologies being studied using the SCaN Testbed include advanced networking, coding, and modulation protocols designed to support the transition of NASAs mission systems from primarily point to point data links and preplanned routes towards adaptive, autonomous internetworked operations needed to meet future mission objectives. Networking protocols implemented on the SCaN Testbed include the Advanced Orbiting Systems (AOS) link-layer protocol, Consultative Committee for Space Data Systems (CCSDS) Encapsulation Packets, Internet Protocol (IP), Space Link Extension (SLE), CCSDS File Delivery Protocol (CFDP), and Delay-Tolerant Networking (DTN) protocols including the Bundle Protocol (BP) and Licklider Transmission Protocol (LTP). The SCaN Testbed end-to-end system provides three S-band data links and one Ka-band data link to exchange space and ground data through NASAs Tracking Data Relay Satellite System or a direct-to-ground link to ground stations. The multiple data links and nodes provide several upgradable elements on both the space and ground systems. This paper will provide a general description of the testbeds system design and capabilities, discuss in detail the design and lessons learned in the implementation of the network protocols, and describe future plans for continuing research to meet the communication needs for evolving global space systems.

Investigation of transient overvoltages in heavily meshed low-voltage underground distribution networks

NASA Astrophysics Data System (ADS)

Salcedo Ulerio, Reynaldo Odalis

The analysis of overvoltages in electrical distribution networks is of considerable significance since they may damage the power system infrastructure and the associated electrical equipment. Overvoltages in distribution networks arise due to switching transients, resonance, lightning strikes and ground faults, among other causes. The operation of network protectors (NWP), low voltage circuit breakers with directional power relay, in a secondary network prevents the continuous flow of reverse power. There are three modes of operation for the network protectors: sensitive, time delayed, and insensitive. In case of a fault, although all of the network protectors sense the fault at the same time, their operation is not simultaneous. Many of them open very quickly with opening times similar to those of the feeder breaker. However, some operate a few cycles later, others take several seconds to open and a few might even fail to operate. Therefore, depending on the settings of the network protectors, faults can last for significantly long time due to backfeeding of current from the low voltage (LV) network into the medium voltage (MV) network. In this work, low voltages are defined as 208V/460V and medium voltage are defined as 25kV/35kV. This thesis presents overvoltages which arise because of the occurrence of a single-line-to-ground (SLG) fault on the MV side (connected in delta) of the system. The thesis reveals that overvoltage stresses are imposed on insulation, micro-processor controlled equipment, and switching devices by overvoltages during current backfeeding. Also, it establishes a relationship between overvoltage magnitude, its duration, and the network loading conditions. Overvoltages above 3 p.u. may be developed as a result of a simultaneous occurrence of three phenomena: neutral displacement, Ferranti effect, and magnetic current chopping. Furthermore, this thesis exposes the possibility of occurrence of the ferro-resonance phenomena in a distribution network having secondary grid, making the study of extreme importance especially in the case of a misoperating network protector. The test systems for both studies were designed following the conventional distribution network with secondary grid, similar to those in the New York City Area. Simulations were performed using the electro-magnetic transient program revised version (EMTP-RV) considering detailed representation of system components as well as the non-linear magnetization and losses of transformers.

Analysis and Simulation of Traffic Control for Resource Management in DVB-Based Broadband Satellite Access Networks

NASA Astrophysics Data System (ADS)

Impemba, Ernesto; Inzerilli, Tiziano

2003-07-01

Integration of satellite access networks with the Internet is seen as a strategic goal to achieve in order to provide ubiquitous broadband access to Internet services in Next Generation Networks (NGNs). One of the main interworking aspects which has been most studied is an efficient management of satellite resources, i.e. bandwidth and buffer space, in order to satisfy most demanding application requirements as to delay control and bandwidth assurance. In this context, resource management in DVB-S/DVB-RCS satellite technologies, emerging technologies for broadband satellite access and transport of IP applications, is a research issue largely investigated as a means to provide efficient bi-directional communications across satellites. This is in particular one of the principal goals of the SATIP6 project, sponsored within the 5th EU Research Programme Framework, i.e. IST. In this paper we present a possible approach to efficiently exploit bandwidth, the most critical resource in a broadband satellite access network, while pursuing satisfaction of delay and bandwidth requirements for applications with guaranteed QoS through a traffic control architecture to be implemented in ground terminals. Performance of this approach is assessed in terms of efficient exploitation of the uplink bandwidth and differentiation and minimization of queuing delays for most demanding applications over a time-varying capacity. Opnet simulations is used as analysis tool.

LAGO: The Latin American giant observatory

NASA Astrophysics Data System (ADS)

Sidelnik, Iván; Asorey, Hernán; LAGO Collaboration

2017-12-01

The Latin American Giant Observatory (LAGO) is an extended cosmic ray observatory composed of a network of water-Cherenkov detectors (WCD) spanning over different sites located at significantly different altitudes (from sea level up to more than 5000 m a.s.l.) and latitudes across Latin America, covering a wide range of geomagnetic rigidity cut-offs and atmospheric absorption/reaction levels. The LAGO WCD is simple and robust, and incorporates several integrated devices to allow time synchronization, autonomous operation, on board data analysis, as well as remote control and automated data transfer. This detection network is designed to make detailed measurements of the temporal evolution of the radiation flux coming from outer space at ground level. LAGO is mainly oriented to perform basic research in three areas: high energy phenomena, space weather and atmospheric radiation at ground level. It is an observatory designed, built and operated by the LAGO Collaboration, a non-centralized collaborative union of more than 30 institutions from ten countries. In this paper we describe the scientific and academic goals of the LAGO project - illustrating its present status with some recent results - and outline its future perspectives.

Intrasite motions and monument instabilities at Medicina ITRF co-location site

NASA Astrophysics Data System (ADS)

Sarti, Pierguido; Abbondanza, Claudio; Legrand, Juliette; Bruyninx, Carine; Vittuari, Luca; Ray, Jim

2013-03-01

We process the total-station surveys performed at the ITRF co-location site Medicina (Northern Italy) over the decade (2001-2010) with the purpose of determining the extent of local intrasite motions and relating them to local geophysical processes, the geological setting and the design of the ground pillars. In addition, continuous observations acquired by two co-located GPS stations (MEDI and MSEL separated by ≈27 m) are analysed and their relative motion is cross-checked with the total-station results. The local ground control network extends over a small area (<100 × 100 m) but the results demonstrate significant anisotropic deformations with rates up to 1.6 mm a-1, primarily horizontal, a value comparable to intraplate tectonic deformations. The results derived from GPS and total-station observations are consistent and point to the presence of horizontal intrasite motions over very short distances possibly associated with varying environmental conditions in a very unfavourable local geological setting and unsuitable monument design, these latter being crucial aspects of the realization and maintenance of global permanent geodetic networks and the global terrestrial reference frame.

Land mobile satellite system requirements

NASA Astrophysics Data System (ADS)

Kiesling, J. D.

1983-05-01

A Land Mobile Satellite System (LMSS) provides voice, data and related communications services to moving vehicles and persons. Communications between the mobiles and satellite are in the 806-890 MHz band. The satellite translates these signals to a ""fixed services band'' such as 14/12 GHz band (Ku-band), and communicates in this band with fixed terminals called gateways. The gateways are located at convenient places such as telephone switches (which provide entry into the national telephone system), dispatcher headquarters, computer centers, etc. Communications are therefore principally mobile to fixed. A third communications link, also at Ku-band, is needed between the satellite and a single fixed ground station. This link provides satellite command, telemetry and ranging and also provides a network control function. The latter, through a common signalling system, receives requests and assigns channel slots, and otherwise controls, monitors and polices the network and collects billing information.

Land mobile satellite system requirements

NASA Technical Reports Server (NTRS)

Kiesling, J. D.

1983-01-01

A Land Mobile Satellite System (LMSS) provides voice, data and related communications services to moving vehicles and persons. Communications between the mobiles and satellite are in the 806-890 MHz band. The satellite translates these signals to a ""fixed services band'' such as 14/12 GHz band (Ku-band), and communicates in this band with fixed terminals called gateways. The gateways are located at convenient places such as telephone switches (which provide entry into the national telephone system), dispatcher headquarters, computer centers, etc. Communications are therefore principally mobile to fixed. A third communications link, also at Ku-band, is needed between the satellite and a single fixed ground station. This link provides satellite command, telemetry and ranging and also provides a network control function. The latter, through a common signalling system, receives requests and assigns channel slots, and otherwise controls, monitors and polices the network and collects billing information.

Dynamic optimization of ISR sensors using a risk-based reward function applied to ground and space surveillance scenarios

NASA Astrophysics Data System (ADS)

DeSena, J. T.; Martin, S. R.; Clarke, J. C.; Dutrow, D. A.; Newman, A. J.

2012-06-01

As the number and diversity of sensing assets available for intelligence, surveillance and reconnaissance (ISR) operations continues to expand, the limited ability of human operators to effectively manage, control and exploit the ISR ensemble is exceeded, leading to reduced operational effectiveness. Automated support both in the processing of voluminous sensor data and sensor asset control can relieve the burden of human operators to support operation of larger ISR ensembles. In dynamic environments it is essential to react quickly to current information to avoid stale, sub-optimal plans. Our approach is to apply the principles of feedback control to ISR operations, "closing the loop" from the sensor collections through automated processing to ISR asset control. Previous work by the authors demonstrated non-myopic multiple platform trajectory control using a receding horizon controller in a closed feedback loop with a multiple hypothesis tracker applied to multi-target search and track simulation scenarios in the ground and space domains. This paper presents extensions in both size and scope of the previous work, demonstrating closed-loop control, involving both platform routing and sensor pointing, of a multisensor, multi-platform ISR ensemble tasked with providing situational awareness and performing search, track and classification of multiple moving ground targets in irregular warfare scenarios. The closed-loop ISR system is fullyrealized using distributed, asynchronous components that communicate over a network. The closed-loop ISR system has been exercised via a networked simulation test bed against a scenario in the Afghanistan theater implemented using high-fidelity terrain and imagery data. In addition, the system has been applied to space surveillance scenarios requiring tracking of space objects where current deliberative, manually intensive processes for managing sensor assets are insufficiently responsive. Simulation experiment results are presented. The algorithm to jointly optimize sensor schedules against search, track, and classify is based on recent work by Papageorgiou and Raykin on risk-based sensor management. It uses a risk-based objective function and attempts to minimize and balance the risks of misclassifying and losing track on an object. It supports the requirement to generate tasking for metric and feature data concurrently and synergistically, and account for both tracking accuracy and object characterization, jointly, in computing reward and cost for optimizing tasking decisions.

Lightning location system supervising Swedish power transmission network

NASA Technical Reports Server (NTRS)

Melin, Stefan A.

1991-01-01

For electric utilities, the ability to prevent or minimize lightning damage on personnel and power systems is of great importance. Therefore, the Swedish State Power Board, has been using data since 1983 from a nationwide lightning location system (LLS) for accurately locating lightning ground strikes. Lightning data is distributed and presented on color graphic displays at regional power network control centers as well as at the national power system control center for optimal data use. The main objectives for use of LLS data are: supervising the power system for optimal and safe use of the transmission and generating capacity during periods of thunderstorms; warning service to maintenance and service crews at power line and substations to end operations hazardous when lightning; rapid positioning of emergency crews to locate network damage at areas of detected lightning; and post analysis of power outages and transmission faults in relation to lightning, using archived lightning data for determination of appropriate design and insulation levels of equipment. Staff have found LLS data useful and economically justified since the availability of power system has increased as well as level of personnel safety.

The advances in airglow study and observation by the ground-based airglow observation network over China

NASA Astrophysics Data System (ADS)

Xu, Jiyao; Li, Qinzeng; Yuan, Wei; Liu, Xiao; Liu, Weijun; Sun, Longchang

2017-04-01

Ground-based airglow observation networks over China used to study airglow have been established, which contains 15 stations. Some new results were obtained using the networks. For OH airglow observations, firstly, an unusual outbreak of Concentric Gravity Wave (CGW) events were observed by the first no-gap network nearly every night during the first half of August 2013. Combination of the ground imager network with satellites provides multilevel observations of the CGWs from the troposphere to the mesopause region. Secondly, three-year OH airglow images (2012-2014) from Qujing (25.6°N, 103.7°E) were used to study how orographic features of the Tibetan Plateau (TP) affect the geographical distributions of gravity wave (GW) sources. We find the orographic forcings have a significant impact on the gravity wave propagation features. Thirdly, ground-based observations of the OH (9-4, 8-3, 6-2, 5-1, 3-0) band airglow over Xinglong (40°2N, 117°4E) in northern China from 2012 to 2014 are used to calculate rotational temperatures. By comparing the ground-based OH rotational temperature with SABER's observations, five Einstein coefficient datasets are evaluated. We find rotational temperatures determined using any of the available Einstein coefficient datasets have systematic errors. We have obtained a set of optimal Einstein coefficients ratios for rotational temperature derivation using three years data from ground-based OH spectra and SABER temperatures. For the OI 630.0 nm airglow observations, we used three-year (2011-2013) observations of thermospheric winds (at 250 km) by Fabry-Perot interferometers at Xinglong to study the climatology of atmospheric planetary wave-type oscillations (PWTOs) with periods of 4-19 days. We found these PWTOs occur more frequently in the months from May to October. They are consistent with the summertime preference of middle-latitude ionospheric electron density oscillations noted in other studies. By using an all-sky airglow imager at 630.0 nm over Xinglong, we studied the evolution (generation, amplification, and dissipation) of mesoscale field-aligned irregularity structures (FAIs) ( 150 km) associated with a medium-scale traveling ionospheric disturbance (MSTID) event. We also investigates the statistical features of equatorial plasma bubbles (EPBs) using airglow images from 2012 to 2014 from a ground-based network of four imagers in the equatorial region of China.

Electrical and mechanical tuning of a silicon vacancy defect in SiC for quantum information technology

NASA Astrophysics Data System (ADS)

Soykal, Oney O.; Reinecke, Thomas L.

We develop coherent control via Stark effect over the optical transition energies of silicon monovacancy deep center in hexagonal silicon carbide. We show that this defect's unique asymmetry properties of its piezoelectric tensor and Kramer's degenerate high-spin ground/excited state configurations can be used to create new possibilities in quantum information technology ranging from photonic networks to quantum key distribution. We also give examples of its qubit implementations via precise electric field control. This work was supported in part by ONR and by the Office of Secretary of Defense, Quantum Science and Engineering Program.

Study of orbiter/payload interface communications configuration control board directive from an operational perspective

NASA Technical Reports Server (NTRS)

Addis, A. W.; Tatosian, C. G.; Lidsey, J. F.

1974-01-01

Orbiter/payload data and communications interface was examined. It was found that the Configuration Control Board Directive (CCBD) greatly increases the capability of the orbiter to communicate with a wide variety of projected shuttle payloads. Rather than being derived from individual payload communication requirements, the CCBD appears to be based on an operational philosophy that requires the orbiter to duplicate or augment the ground network/payload communication links. It is suggested that the implementation of the CCBD be reviewed and compared with the Level 1 Program Requirements Document, differences reconciled, and interface characteristics defined.

A decision algorithm for determining safe clearing limits for the construction of skid roads

Treesearch

Chris LeDoux

2006-01-01

The majority of the timber harvested in the United States is extracted by ground-based skidders and crawler/dozer systems. Ground-based systems generally require a primary transportation network (a network of skid trails/roads) throughout the area being harvested. Logs are skidded or dragged along these skid roads/trails as they are transported from where they were cut...

The Telecommunications and Data Acquisition Report. [Deep Space Network

NASA Technical Reports Server (NTRS)

Posner, E. C. (Editor)

1988-01-01

In space communications, radio navigation, radio science, and ground based radio and radar astronomy, activities of the Deep Space Network and its associated Ground Communications Facility in planning, in supporting research and technology, in implementation, and in operations are reported. Also included is TDA funded activity at JPL on data and information systems and reimbursable DSN work performed for other space agencies through NASA.

Potential Use of a Bayesian Network for Discriminating Flash Type from Future GOES-R Geostationary Lightning Mapper (GLM) data

NASA Technical Reports Server (NTRS)

Solakiewiz, Richard; Koshak, William

2008-01-01

Continuous monitoring of the ratio of cloud flashes to ground flashes may provide a better understanding of thunderstorm dynamics, intensification, and evolution, and it may be useful in severe weather warning. The National Lighting Detection Network TM (NLDN) senses ground flashes with exceptional detection efficiency and accuracy over most of the continental United States. A proposed Geostationary Lightning Mapper (GLM) aboard the Geostationary Operational Environmental Satellite (GOES-R) will look at the western hemisphere, and among the lightning data products to be made available will be the fundamental optical flash parameters for both cloud and ground flashes: radiance, area, duration, number of optical groups, and number of optical events. Previous studies have demonstrated that the optical flash parameter statistics of ground and cloud lightning, which are observable from space, are significantly different. This study investigates a Bayesian network methodology for discriminating lightning flash type (ground or cloud) using the lightning optical data and ancillary GOES-R data. A Directed Acyclic Graph (DAG) is set up with lightning as a "root" and data observed by GLM as the "leaves." This allows for a direct calculation of the joint probability distribution function for the lighting type and radiance, area, etc. Initially, the conditional probabilities that will be required can be estimated from the Lightning Imaging Sensor (LIS) and the Optical Transient Detector (OTD) together with NLDN data. Directly manipulating the joint distribution will yield the conditional probability that a lightning flash is a ground flash given the evidence, which consists of the observed lightning optical data [and possibly cloud data retrieved from the GOES-R Advanced Baseline Imager (ABI) in a more mature Bayesian network configuration]. Later, actual GLM and NLDN data can be used to refine the estimates of the conditional probabilities used in the model; i.e., the Bayesian network is a learning network. Methods for efficient calculation of the conditional probabilities (e.g., an algorithm using junction trees), finding data conflicts, goodness of fit, and dealing with missing data will also be addressed.

The Power of Ground User in Recommender Systems

PubMed Central

Zhou, Yanbo; Lü, Linyuan; Liu, Weiping; Zhang, Jianlin

2013-01-01

Accuracy and diversity are two important aspects to evaluate the performance of recommender systems. Two diffusion-based methods were proposed respectively inspired by the mass diffusion (MD) and heat conduction (HC) processes on networks. It has been pointed out that MD has high recommendation accuracy yet low diversity, while HC succeeds in seeking out novel or niche items but with relatively low accuracy. The accuracy-diversity dilemma is a long-term challenge in recommender systems. To solve this problem, we introduced a background temperature by adding a ground user who connects to all the items in the user-item bipartite network. Performing the HC algorithm on the network with ground user (GHC), it showed that the accuracy can be largely improved while keeping the diversity. Furthermore, we proposed a weighted form of the ground user (WGHC) by assigning some weights to the newly added links between the ground user and the items. By turning the weight as a free parameter, an optimal value subject to the highest accuracy is obtained. Experimental results on three benchmark data sets showed that the WGHC outperforms the state-of-the-art method MD for both accuracy and diversity. PMID:23936380

Illinois ground-water observation network; a preliminary planning document for network design

USGS Publications Warehouse

Frost, L.R.; O'Hearn, Michael; Gibb, J.P.; Sherrill, M.G.

1984-01-01

Water-level and water-quality networks in Illinois were evaluated to determine the adequacy and completeness of available data bases. Ground-water data in present data bases are inadequate to provide information on ground-water quality and water levels in large areas of Illinois and in the major geohydrologic units underlying Illinois and surrounding areas. Data-management needs indicate that a new data base is desirable and could be developed by use of carefully selected available data and new data. Types of data needed to define ground-water quality and water levels in selected geohydrologic units were tentatively identified. They include data on concentrations of organic chemicals related to activities of man, and concentrations of inorganic chemicals which relate either to man 's activities or to the chemical composition of the source aquifer. Water-level data are needed which can be used to describe short- and long-term stresses on the ground-water resources of Illinois. Establishment of priorities for data collection has been deferred until existing hydrologic data files can be stored for usable data and until input from other local, State, and Federal agencies can be solicited and compiled. (USGS)

Detection performance of three different lightning location networks in Beijing area based on accurate fast antenna records

NASA Astrophysics Data System (ADS)

Srivastava, A.; Tian, Y.; Wang, D.; Yuan, S.; Chen, Z.; Sun, Z.; Qie, X.

2016-12-01

Scientists have developed the regional and worldwide lightning location network to study the lightning physics and locating the lightning stroke. One of the key issue in all the networks; to recognize the performance of the network. The performance of each network would be different based on the regional geographic conditions and the instrumental limitation. To improve the performance of the network. it is necessary to know the ground truth of the network and to discuss about the detection efficiency (DE) and location accuracy (LA). A comparative study has been discussed among World Wide Lightning Location Network (WWLLN), ADvanced TOA and Direction system (ADTD) and Beijing Lightning NETwork (BLNET) lightning detection network in Beijing area. WWLLN locate the cloud to ground (CG) and strong inter cloud (IC) globally without demonstrating any differences. ADTD locate the CG strokes in the entire China as regional. Both these networks are long range detection system that does not provide the focused details of a thunderstorm. BLNET can locate the CG and IC and is focused on thunderstorm detection. The waveform of fast antenna checked manually and the relative DE among the three networks has been obtained based on the CG strokes. The relative LA has been obtained using the matched flashes among these networks as well as LA obtained using the strike on the tower. The relative DE of BLNET is much higher than the ADTD and WWLLN as these networks has approximately similar relative DE. The relative LA of WWLLN and ADTD location is eastward and northward respectively from the BLNET. The LA based on tower observation is relatively high-quality in favor of BLNET. The ground truth of WWLLN, ADTD and BLNET has been obtained and found the performance of BLNET network is much better. This study is helpful to improve the performance of the networks and to provide a belief of LA that can follow the thunderstorm path with the prediction and forecasting of thunderstorm and lightning.

The ground truth about metadata and community detection in networks

PubMed Central

Peel, Leto; Larremore, Daniel B.; Clauset, Aaron

2017-01-01

Across many scientific domains, there is a common need to automatically extract a simplified view or coarse-graining of how a complex system’s components interact. This general task is called community detection in networks and is analogous to searching for clusters in independent vector data. It is common to evaluate the performance of community detection algorithms by their ability to find so-called ground truth communities. This works well in synthetic networks with planted communities because these networks’ links are formed explicitly based on those known communities. However, there are no planted communities in real-world networks. Instead, it is standard practice to treat some observed discrete-valued node attributes, or metadata, as ground truth. We show that metadata are not the same as ground truth and that treating them as such induces severe theoretical and practical problems. We prove that no algorithm can uniquely solve community detection, and we prove a general No Free Lunch theorem for community detection, which implies that there can be no algorithm that is optimal for all possible community detection tasks. However, community detection remains a powerful tool and node metadata still have value, so a careful exploration of their relationship with network structure can yield insights of genuine worth. We illustrate this point by introducing two statistical techniques that can quantify the relationship between metadata and community structure for a broad class of models. We demonstrate these techniques using both synthetic and real-world networks, and for multiple types of metadata and community structures. PMID:28508065

The Telecommunications and Data Acquisition Report

NASA Technical Reports Server (NTRS)

Yuen, Joseph H. (Editor)

1993-01-01

This quarterly publication provides archival reports on developments in programs managed by JPL's Office of Telecommunications and Data Acquisition (TDA). In space communications, radio navigation, radio science, and ground-based radio and radar astronomy, it reports on activities of the Deep Space Network (DSN) in planning, supporting research and technology, implementation, and operations. Also included are standards activity at JPL for space data and information systems and reimbursable DSN work performed for other space agencies through NASA. The papers included in this document cover satellite tracking and ground-based navigation, spacecraft-ground communications, and optical communication systems for the Deep Space Network.

Estimating ground water yield in small research basins

Treesearch

Elon S. Verry

2003-01-01

An analysis of ground water recharge in 32 small research watersheds shows the average flow of ground water out of the watershed (deep seepage) is 45% of streamflow and ranges from 8 to 350 mm/year when apportioned over the watershed area. It is time to meld ground water and small watershed science. The use of we11 networks and the evaluation of ground water well...

Improving the Capture and Re-Use of Data with Wearable Computers

NASA Technical Reports Server (NTRS)

Pfarr, Barbara; Fating, Curtis C.; Green, Daniel; Powers, Edward I. (Technical Monitor)

2001-01-01

At the Goddard Space Flight Center, members of the Real-Time Software Engineering Branch are developing a wearable, wireless, voice-activated computer for use in a wide range of crosscutting space applications that would benefit from having instant Internet, network, and computer access with complete mobility and hands-free operations. These applications can be applied across many fields and disciplines including spacecraft fabrication, integration and testing (including environmental testing), and astronaut on-orbit control and monitoring of experiments with ground based experimenters. To satisfy the needs of NASA customers, this wearable computer needs to be connected to a wireless network, to transmit and receive real-time video over the network, and to receive updated documents via the Internet or NASA servers. The voice-activated computer, with a unique vocabulary, will allow the users to access documentation in a hands free environment and interact in real-time with remote users. We will discuss wearable computer development, hardware and software issues, wireless network limitations, video/audio solutions and difficulties in language development.

GRAVSAT/GEOPAUSE refraction study

NASA Technical Reports Server (NTRS)

Llewellyn, S. K.

1977-01-01

A ground station network tracked a high altitude spacecraft which in turn tracked a low orbiting satellite. Orbit data are relayed back to the ground stations. A refraction study was performed on this configuration to compute ionospheric and tropospheric refraction effects along the satellite and ground links.

Ground Motion Prediction Models for Caucasus Region

NASA Astrophysics Data System (ADS)

Jorjiashvili, Nato; Godoladze, Tea; Tvaradze, Nino; Tumanova, Nino

2016-04-01

Ground motion prediction models (GMPMs) relate ground motion intensity measures to variables describing earthquake source, path, and site effects. Estimation of expected ground motion is a fundamental earthquake hazard assessment. The most commonly used parameter for attenuation relation is peak ground acceleration or spectral acceleration because this parameter gives useful information for Seismic Hazard Assessment. Since 2003 development of Georgian Digital Seismic Network has started. In this study new GMP models are obtained based on new data from Georgian seismic network and also from neighboring countries. Estimation of models is obtained by classical, statistical way, regression analysis. In this study site ground conditions are additionally considered because the same earthquake recorded at the same distance may cause different damage according to ground conditions. Empirical ground-motion prediction models (GMPMs) require adjustment to make them appropriate for site-specific scenarios. However, the process of making such adjustments remains a challenge. This work presents a holistic framework for the development of a peak ground acceleration (PGA) or spectral acceleration (SA) GMPE that is easily adjustable to different seismological conditions and does not suffer from the practical problems associated with adjustments in the response spectral domain.

The Role of Advanced Information System Technology in Remote Sensing for NASA's Earth Science Enterprise in the 21st Century

NASA Technical Reports Server (NTRS)

Prescott, Glenn; Komar, George (Technical Monitor)

2001-01-01

Future NASA Earth observing satellites will carry high-precision instruments capable of producing large amounts of scientific data. The strategy will be to network these instrument-laden satellites into a web-like array of sensors to facilitate the collection, processing, transmission, storage, and distribution of data and data products - the essential elements of what we refer to as "Information Technology." Many of these Information Technologies will enable the satellite and ground information systems to function effectively in real-time, providing scientists with the capability of customizing data collection activities on a satellite or group of satellites directly from the ground. In future systems, extremely large quantities of data collected by scientific instruments will require the fastest processors, the highest communication channel transfer rates, and the largest data storage capacity to insure that data flows smoothly from the satellite-based instrument to the ground-based archive. Autonomous systems will control all essential processes and play a key role in coordinating the data flow through space-based communication networks. In this paper, we will discuss those critical information technologies for Earth observing satellites that will support the next generation of space-based scientific measurements of planet Earth, and insure that data and data products provided by these systems will be accessible to scientists and the user community in general.

The South Fork Experimental Watershed: Soil moisture and precipitation network for satellite validation

NASA Astrophysics Data System (ADS)

Cosh, M. H.; Prueger, J. H.; McKee, L.; Bindlish, R.

2013-12-01

A recently deployed long term network for the study of soil moisture and precipitation was deployed in north central iowa, in cooperation between USDA and NASA. This site will be a joint calibration/validation network for the Soil Moisture Active Passive (SMAP) and Global Precipitation Measurement (GPM) missions. At total of 20 dual gauge precipitation gages were established across a watershed landscape with an area of approximately 600 km2. In addition, four soil moisture probes were installed in profile at 5, 10, 20, and 50 cm. The network was installed in April of 2013, at the initiation of the Iowa Flood Study (IFloodS) which was a six week intensive ground based radar observation period, conducted in coordination with NASA and the University of Iowa. This site is a member watershed of the Group on Earth Observations Joint Experiments on Crop Assessment and Monitoring (GEO-JECAM) program. A variety of quality control procedures are examined and spatial and temporal stability aspects of the network are examined. Initial comparisons of the watershed to soil moisture estimates from satellites are also conducted.

Virtual war, military revolutions, and networks: a guide through the concepts from an Australian perspective

NASA Astrophysics Data System (ADS)

Bowley, Dean K.; Gaertner, Paul S.

2003-07-01

In this paper the argument is made that the offensive fire support organisation and doctrine, born of the "indirect fire revolution" of the first world war, is the start point for distributed sensors, shooters and deciders that may be transferred to a joint force; that the culture of directive control and mission orders developed by the German Army in 1918 and then adopted by most western armies is the start point for the culture required to achieve "self synchronisation" and that the network developed for the air defence of carrier battle groups is the start point for developing a networked ground manoeuvre force. We discuss the strategic expectations of network centric warfare, a "virtual war" scenario and the inherent vulnerabilities. The current level of understanding and implementation in specific areas is analysed and lessons for general application are developed and the potential payoff identified. Three broad operational domains are investigated, networked platform versus platform warfare between states, guerrilla/counter-insurfence operations and the emerging domain of "netwars" (terror organisations and criminal gangs).

Methods for Cloud Cover Estimation

NASA Technical Reports Server (NTRS)

Glackin, D. L.; Huning, J. R.; Smith, J. H.; Logan, T. L.

1984-01-01

Several methods for cloud cover estimation are described relevant to assessing the performance of a ground-based network of solar observatories. The methods rely on ground and satellite data sources and provide meteorological or climatological information. One means of acquiring long-term observations of solar oscillations is the establishment of a ground-based network of solar observatories. Criteria for station site selection are: gross cloudiness, accurate transparency information, and seeing. Alternative methods for computing this duty cycle are discussed. The cycle, or alternatively a time history of solar visibility from the network, can then be input to a model to determine the effect of duty cycle on derived solar seismology parameters. Cloudiness from space is studied to examine various means by which the duty cycle might be computed. Cloudiness, and to some extent transparency, can potentially be estimated from satellite data.

Pacific Educational Computer Network Study. Final Report.

ERIC Educational Resources Information Center

Hawaii Univ., Honolulu. ALOHA System.

The Pacific Educational Computer Network Feasibility Study examined technical and non-technical aspects of the formation of an international Pacific Area computer network for higher education. The technical study covered the assessment of the feasibility of a packet-switched satellite and radio ground distribution network for data transmission…

GCF Mark IV development

NASA Technical Reports Server (NTRS)

Mortensen, L. O.

1982-01-01

The Mark IV ground communication facility (GCF) as it is implemented to support the network consolidation program is reviewed. Changes in the GCF are made in the area of increased capacity. Common carrier circuits are the medium for data transfer. The message multiplexing in the Mark IV era differs from the Mark III era, in that all multiplexing is done in a GCF computer under GCF software control, which is similar to the multiplexing currently done in the high speed data subsystem.

Orion Flight Test Architecture Benefits of MBSE Approach

NASA Technical Reports Server (NTRS)

Reed, Don; Simpson, Kim

2012-01-01

Exploration Flight Test 1 (EFT-1) is an unmanned first orbital flight test of the Multi Purpose Crew Vehicle (MPCV) Mission s purpose is to: Test Orion s ascent, on-orbit and entry capabilities Monitor critical activities Provide ground control in support of contingency scenarios Requires development of a large scale end-to-end information system network architecture To effectively communicate the scope of the end-to-end system a model-based system engineering approach was chosen.

Develop Measures of Effectiveness and Deployment Optimization Rules for Networked Ground Micro-Sensors

DTIC Science & Technology

2001-05-01

types and total #) Ø Control of Sensors ( Scheduling ) Ø Coverage (Time & Area) Uncontrollable Inputs ØWeather Ø Atmospheric Effects Ø Equipment...are widely scattered and used to cue or wakeup other higher-level sensors. Trip line sensors consist of some combination of acoustic, seismic and...Employ a mix if different sensor types in order to increase detection probability 4.4.4.2 Minimize Battery Power • Set schedule turn on and off

Using Causal Models to Manage the Cyber Threat to C2 Agility: Working with the Benefit of Hindsight

DTIC Science & Technology

2014-06-01

comprising event types that begin with access to the Ground Control Station network (‘Reconnaissance’), carry out persona management activities leading to...occurring. Figure 9 shows a chain where ‘GCS Hostile Persona Management’ has been detected, leading to a heightened assessment of the probability of...evidence occurs of hostile persona management that calls into question the integrity of the mission itself. What now: search for a mitigation, assess

Locomotion training of legged robots using hybrid machine learning techniques

NASA Technical Reports Server (NTRS)

Simon, William E.; Doerschuk, Peggy I.; Zhang, Wen-Ran; Li, Andrew L.

1995-01-01

In this study artificial neural networks and fuzzy logic are used to control the jumping behavior of a three-link uniped robot. The biped locomotion control problem is an increment of the uniped locomotion control. Study of legged locomotion dynamics indicates that a hierarchical controller is required to control the behavior of a legged robot. A structured control strategy is suggested which includes navigator, motion planner, biped coordinator and uniped controllers. A three-link uniped robot simulation is developed to be used as the plant. Neurocontrollers were trained both online and offline. In the case of on-line training, a reinforcement learning technique was used to train the neurocontroller to make the robot jump to a specified height. After several hundred iterations of training, the plant output achieved an accuracy of 7.4%. However, when jump distance and body angular momentum were also included in the control objectives, training time became impractically long. In the case of off-line training, a three-layered backpropagation (BP) network was first used with three inputs, three outputs and 15 to 40 hidden nodes. Pre-generated data were presented to the network with a learning rate as low as 0.003 in order to reach convergence. The low learning rate required for convergence resulted in a very slow training process which took weeks to learn 460 examples. After training, performance of the neurocontroller was rather poor. Consequently, the BP network was replaced by a Cerebeller Model Articulation Controller (CMAC) network. Subsequent experiments described in this document show that the CMAC network is more suitable to the solution of uniped locomotion control problems in terms of both learning efficiency and performance. A new approach is introduced in this report, viz., a self-organizing multiagent cerebeller model for fuzzy-neural control of uniped locomotion is suggested to improve training efficiency. This is currently being evaluated for a possible patent by NASA, Johnson Space Center. An alternative modular approach is also developed which uses separate controllers for each stage of the running stride. A self-organizing fuzzy-neural controller controls the height, distance and angular momentum of the stride. A CMAC-based controller controls the movement of the leg from the time the foot leaves the ground to the time of landing. Because the leg joints are controlled at each time step during flight, movement is smooth and obstacles can be avoided. Initial results indicate that this approach can yield fast, accurate results.

SONG-China Project: A Global Automated Observation Network

NASA Astrophysics Data System (ADS)

Yang, Z. Z.; Lu, X. M.; Tian, J. F.; Zhuang, C. G.; Wang, K.; Deng, L. C.

2017-09-01

Driven by advancements in technology and scientific objectives, data acquisition in observational astronomy has been changed greatly in recent years. Fully automated or even autonomous ground-based network of telescopes has now become a tendency for time-domain observational projects. The Stellar Observations Network Group (SONG) is an international collaboration with the participation and contribution of the Chinese astronomy community. The scientific goal of SONG is time-domain astrophysics such as asteroseismology and open cluster research. The SONG project aims to build a global network of 1 m telescopes equipped with high-precision and high-resolution spectrographs, and two-channel lucky-imaging cameras. It is the Chinese initiative to install a 50 cm binocular photometry telescope at each SONG node sharing the network platform and infrastructure. This work is focused on design and implementation in technology and methodology of SONG/50BiN, a typical ground-based network composed of multiple sites and a variety of instruments.

Network connectivity enhancement by exploiting all optical multicast in semiconductor ring laser

NASA Astrophysics Data System (ADS)

Siraj, M.; Memon, M. I.; Shoaib, M.; Alshebeili, S.

2015-03-01

The use of smart phone and tablet applications will provide the troops for executing, controlling and analyzing sophisticated operations with the commanders providing crucial documents directly to troops wherever and whenever needed. Wireless mesh networks (WMNs) is a cutting edge networking technology which is capable of supporting Joint Tactical radio System (JTRS).WMNs are capable of providing the much needed bandwidth for applications like hand held radios and communication for airborne and ground vehicles. Routing management tasks can be efficiently handled through WMNs through a central command control center. As the spectrum space is congested, cognitive radios are a much welcome technology that will provide much needed bandwidth. They can self-configure themselves, can adapt themselves to the user requirement, provide dynamic spectrum access for minimizing interference and also deliver optimal power output. Sometimes in the indoor environment, there are poor signal issues and reduced coverage. In this paper, a solution utilizing (CR WMNs) over optical network is presented by creating nanocells (PCs) inside the indoor environment. The phenomenon of four-wave mixing (FWM) is exploited to generate all-optical multicast using semiconductor ring laser (SRL). As a result same signal is transmitted at different wavelengths. Every PC is assigned a unique wavelength. By using CR technology in conjunction with PC will not only solve network coverage issue but will provide a good bandwidth to the secondary users.

Ground-Based Network and Supersite Observations to Complement and Enrich EOS Research

NASA Technical Reports Server (NTRS)

Tsay, Si-Chee; Holben, Brent N.; Welton, Ellsworth J.

2011-01-01

Since 1997 NASA has been successfully launching a series of satellites - the Earth Observing System (EOS) - to intensively study, and gain a better understanding of, the Earth as an integrated system. Space-borne remote sensing observations, however, are often plagued by contamination of surface signatures. Thus, ground-based in-situ and remote-sensing measurements, where signals come directly from atmospheric constituents, the sun, and/or the Earth-atmosphere interactions, provide additional information content for comparisons that confirm quantitatively the usefulness of the integrated surface, aircraft, and satellite datasets. Through numerous participations, particularly but not limited to the EOS remote-sensing/retrieval and validation projects over the years, NASA/GSFC has developed and continuously refined ground-based networks and mobile observatories that proved to be vital in providing high temporal measurements, which complement and enrich the satellite observations. These are: the AERO NET (AErosol RObotic NETwork) a federation of ground-based globally distributed network of spectral sun-sky photometers; the MPLNET (Micro-Pulse Lidar NETwork, a similarly organized network of micro-pulse lidar systems measuring aerosol and cloud vertical structure continuously; and the SMART-COMMIT (Surface-sensing Measurements for Atmospheric Radiative Transfer - Chemical, Optical & Microphysical Measurements of In-situ Troposphere, mobile observatories, a suite of spectral radiometers and in-situ probes acquiring supersite measurements. Most MPLNET sites are collocated with those of AERONET, and both networks always support the deployment of SMART-COMMIT worldwide. These data products follow the data structure of EOS conventions: Level-0, instrument archived raw data; Level-1 (or 1.5), real-time data with no (or limited) quality assurance; Level-2, not real high temporal and spectral resolutions. In this talk, we will present NASA/GSFC groundbased facilities, serving as network or supersite observations, which have been playing key roles in major international research projects over diverse aerosol regimes to complement and enrich the EOS scientific research.

CNES-NASA Disruption-Tolerant Networking (DTN) Interoperability

NASA Technical Reports Server (NTRS)

Mortensen, Dale; Eddy, Wesley M.; Reinhart, Richard C.; Lassere, Francois

2014-01-01

Future missions requiring robust internetworking services may use Delay-Disruption-Tolerant Networking (DTN) technology. CNES, NASA, and other international space agencies are committed to using CCSDS standards in their space and ground mission communications systems. The experiment described in this presentation will evaluate operations concepts, system performance, and advance technology readiness for the use of DTN protocols in conjunction with CCSDS ground systems, CCSDS data links, and CCSDS file transfer applications

The Earth Based Ground Stations Element of the Lunar Program

NASA Technical Reports Server (NTRS)

Gal-Edd, Jonathan; Fatig, Curtis; Schier, James; Lee, Charles

2007-01-01

The Lunar Architecture Team (LAT) is responsible for developing a concept for building and supporting a lunar outpost with several exploration capabilities such as rovers, colonization, and observatories. The lunar outpost is planned to be located at the Moon's South Pole. The LAT Communications and Navigation Team (C&N) is responsible for defining the network infrastructure to support the lunar outpost. The following elements are needed to support lunar outpost activities: A Lunar surface network based on industry standard wireless 802.xx protocols, relay satellites positioned 180 degrees apart to provide South Pole coverage for the half of the lunar 28-day orbit that is obscured from Earth view, earth-based ground stations deployed at geographical locations 120 degrees apart. This paper will focus on the Earth ground stations of the lunar architecture. Two types of ground station networks are discussed. One provides Direct to Earth (DTE) support to lunar users using Kaband 23/26Giga-Hertz (GHz) communication frequencies. The second supports the Lunar Relay Satellite (LRS) that will be using Ka-band 40/37GHz (Q-band). This paper will discuss strategies to provide a robust operational network in support of various lunar missions and trades of building new antennas at non-NASA facilities, to improve coverage and provide site diversification for handling rain attenuation.

Knowledge engineering for temporal dependency networks as operations procedures. [in space communication

NASA Technical Reports Server (NTRS)

Fayyad, Kristina E.; Hill, Randall W., Jr.; Wyatt, E. J.

1993-01-01

This paper presents a case study of the knowledge engineering process employed to support the Link Monitor and Control Operator Assistant (LMCOA). The LMCOA is a prototype system which automates the configuration, calibration, test, and operation (referred to as precalibration) of the communications, data processing, metric data, antenna, and other equipment used to support space-ground communications with deep space spacecraft in NASA's Deep Space Network (DSN). The primary knowledge base in the LMCOA is the Temporal Dependency Network (TDN), a directed graph which provides a procedural representation of the precalibration operation. The TDN incorporates precedence, temporal, and state constraints and uses several supporting knowledge bases and data bases. The paper provides a brief background on the DSN, and describes the evolution of the TDN and supporting knowledge bases, the process used for knowledge engineering, and an analysis of the successes and problems of the knowledge engineering effort.

Benefits of Delay Tolerant Networking for Earth Science Missions

NASA Technical Reports Server (NTRS)

Davis, Faith; Marquart, Jane; Menke, Greg

2012-01-01

To date there has been much discussion about the value of Delay Tolerant Networking (DTN) for space missions. Claims of various benefits, based on paper analysis, are good; however a benefits statement with empirical evidence to support is even better. This paper presents potential and actual advantages of using DTN for Earth science missions based on results from multiple demonstrations, conducted by the Communications, Standards, and Technology Laboratory (CSTL) at NASA Goddard Space Flight Center (GSFC). Demonstrations included two flight demonstrations using the Earth Observing Mission 1 (EO-1) and the Near Earth Network (NEN), a ground based demonstration over satellite links to the Internet Router in Space (IRIS) payload on Intelsat-14, and others using the NASA Tracking Data Relay Satellite System (TDRSS). Real and potential findings include increased flexibility and efficiency in science campaigns, reduced latency in a collaborative science scenario, and improved scientist-instrument communication and control.

Noise isolation system for high-speed circuits

DOEpatents

McNeilly, D.R.

1983-12-29

A noise isolation circuit is provided that consists of a dual function bypass which confines high-speed switching noise to the component or circuit which generates it and isolates the component or circuit from high-frequency noise transients which may be present on the ground and power supply busses. A local circuit ground is provided which is coupled to the system ground by sufficient impedance to force the dissipation of the noise signal in the local circuit or component generating the noise. The dual function bypass network couples high-frequency noise signals generated in the local component or circuit through a capacitor to the local ground while isolating the component or circuit from noise signals which may be present on the power supply busses or system ground. The network is an effective noise isolating system and is applicable to both high-speed analog and digital circuits.

Noise isolation system for high-speed circuits

DOEpatents

McNeilly, David R.

1986-01-01

A noise isolation circuit is provided that consists of a dual function bypass which confines high-speed switching noise to the component or circuit which generates it and isolates the component or circuit from high-frequency noise transients which may be present on the ground and power supply busses. A local circuit ground is provided which is coupled to the system ground by sufficient impedance to force the dissipation of the noise signal in the local circuit or component generating the noise. The dual function bypass network couples high-frequency noise signals generated in the local component or circuit through a capacitor to the local ground while isolating the component or circuit from noise signals which may be present on the power supply busses or system ground. The network is an effective noise isolating system and is applicable to both high-speed analog and digital circuits.

An Optimum Space-to-Ground Communication Concept for CubeSat Platform Utilizing NASA Space Network and Near Earth Network

NASA Technical Reports Server (NTRS)

Wong, Yen F.; Kegege, Obadiah; Schaire, Scott H.; Bussey, George; Altunc, Serhat; Zhang, Yuwen; Patel, Chitra

2016-01-01

National Aeronautics and Space Administration (NASA) CubeSat missions are expected to grow rapidly in the next decade. Higher data rate CubeSats are transitioning away from Amateur Radio bands to higher frequency bands. A high-level communication architecture for future space-to-ground CubeSat communication was proposed within NASA Goddard Space Flight Center. This architecture addresses CubeSat direct-to-ground communication, CubeSat to Tracking Data Relay Satellite System (TDRSS) communication, CubeSat constellation with Mothership direct-to-ground communication, and CubeSat Constellation with Mothership communication through K-Band Single Access (KSA).A Study has been performed to explore this communication architecture, through simulations, analyses, and identifying technologies, to develop the optimum communication concepts for CubeSat communications. This paper will present details of the simulation and analysis that include CubeSat swarm, daughter shipmother ship constellation, Near Earth Network (NEN) S and X-band direct to ground link, TDRS Multiple Access (MA) array vs Single Access mode, notional transceiverantenna configurations, ground asset configurations and Code Division Multiple Access (CDMA) signal trades for daughter mother CubeSat constellation inter-satellite crosslink. Results of Space Science X-band 10 MHz maximum achievable data rate study will be summarized. Assessment of Technology Readiness Level (TRL) of current CubeSat communication technologies capabilities will be presented. Compatibility test of the CubeSat transceiver through NEN and Space Network (SN) will be discussed. Based on the analyses, signal trade studies and technology assessments, the functional design and performance requirements as well as operation concepts for future CubeSat end-to-end communications will be derived.

The Engineering Strong Ground Motion Network of the National Autonomous University of Mexico

NASA Astrophysics Data System (ADS)

Velasco Miranda, J. M.; Ramirez-Guzman, L.; Aguilar Calderon, L. A.; Almora Mata, D.; Ayala Hernandez, M.; Castro Parra, G.; Molina Avila, I.; Mora, A.; Torres Noguez, M.; Vazquez Larquet, R.

2014-12-01

The coverage, design, operation and monitoring capabilities of the strong ground motion program at the Institute of Engineering (IE) of the National Autonomous University of Mexico (UNAM) is presented. Started in 1952, the seismic instrumentation intended initially to bolster earthquake engineering projects in Mexico City has evolved into the largest strong ground motion monitoring system in the region. Today, it provides information not only to engineering projects, but also to the near real-time risk mitigation systems of the country, and enhances the general understanding of the effects and causes of earthquakes in Mexico. The IE network includes more than 100 free-field stations and several buildings, covering the largest urban centers and zones of significant seismicity in Central Mexico. Of those stations, approximately one-fourth send the observed acceleration to a processing center in Mexico City continuously, and the rest require either periodic visits for the manual recovery of the data or remote interrogation, for later processing and cataloging. In this research, we document the procedures and telecommunications systems used systematically to recover information. Additionally, we analyze the spatial distribution of the free-field accelerographs, the quality of the instrumentation, and the recorded ground motions. The evaluation criteria are based on the: 1) uncertainty in the generation of ground motion parameter maps due to the spatial distribution of the stations, 2) potential of the array to provide localization and magnitude estimates for earthquakes with magnitudes greater than Mw 5, and 3) adequacy of the network for the development of Ground Motion Prediction Equations due to intra-plate and intra-slab earthquakes. We conclude that the monitoring system requires a new redistribution, additional stations, and a substantial improvement in the instrumentation and telecommunications. Finally, we present an integral plan to improve the current network's monitoring capabilities.

Orbit Determination Issues for Libration Point Orbits

NASA Technical Reports Server (NTRS)

Beckman, Mark; Bauer, Frank (Technical Monitor)

2002-01-01

Libration point mission designers require knowledge of orbital accuracy for a variety of analyses including station keeping control strategies, transfer trajectory design, and formation and constellation control. Past publications have detailed orbit determination (OD) results from individual libration point missions. This paper collects both published and unpublished results from four previous libration point missions (ISEE (International Sun-Earth Explorer) -3, SOHO (Solar and Heliospheric Observatory), ACE (Advanced Composition Explorer) and MAP (Microwave Anisotropy Probe)) supported by Goddard Space Flight Center's Guidance, Navigation & Control Center. The results of those missions are presented along with OD issues specific to each mission. All past missions have been limited to ground based tracking through NASA ground sites using standard range and Doppler measurement types. Advanced technology is enabling other OD options including onboard navigation using seaboard attitude sensors and the use of the Very Long Baseline Interferometry (VLBI) measurement Delta Differenced One-Way Range (DDOR). Both options potentially enable missions to reduce coherent dedicated tracking passes while maintaining orbital accuracy. With the increased projected loading of the DSN (Deep Space Network), missions must find alternatives to the standard OD scenario.

Effects of local factors and climate on permafrost conditions and distribution in Beiluhe basin, Qinghai-Tibet Plateau, China.

PubMed

Yin, Guoan; Niu, Fujun; Lin, Zhanju; Luo, Jing; Liu, Minghao

2017-03-01

Beiluhe basin is underlain by warm and ice-rich permafrost, and covered by vegetation and soils characteristic of the Qinghai-Tibet Plateau. A field monitoring network was established to investigate permafrost conditions and to assess potential impacts of local factors and climate change. This paper describes the spatial variations in permafrost conditions from instrumented boreholes, controlling environmental factors, and recent thermal evolution of permafrost in the basin. The study area was divided into 10 ecotypes using satellite imagery based classification. The field investigations and cluster analysis of ground temperatures indicated that permafrost underlies most of the ground in swamp meadow, undisturbed alpine meadow, degrading alpine meadow, and desert alpine grassland, but is absent in other cover types. Permafrost-ecotope relations examined over a 2-year (2014-2016) period indicated that: (i) ground surface temperatures varied largely among ecotopes; (ii) annual mean ground temperatures ranged from -1.5 to 0°C in permafrost, indicating sensitive permafrost conditions; (iii) active-layer thicknesses ranged from 1.4m to 3.4m; (iv) ground ice content at the top of permafrost is high, but the active-layer soil is relatively dry. Long-term climate warming has driven thermal changes to permafrost, but ground surface characteristics and soil moisture content strongly influence the ground thermal state. These factors control local-scale spatial variations in permafrost conditions. The warm permafrost in the basin is commonly in thermal disequilibrium, and is sensitive to future climate change. Active-layer thicknesses have increased by at least 42cm and the mean annual ground temperatures have increased by up to 0.2°C in the past 10years over the basin. A permafrost distribution map was produced based on ecotypes, suggesting that permafrost underlies 64% of the study region. Copyright © 2017 Elsevier B.V. All rights reserved.

Smashing the Stovepipe: Leveraging the GMSEC Open Architecture and Advanced IT Automation to Rapidly Prototype, Develop and Deploy Next-Generation Multi-Mission Ground Systems

NASA Technical Reports Server (NTRS)

Swenson, Paul

2017-01-01

Satellite/Payload Ground Systems - Typically highly-customized to a specific mission's use cases - Utilize hundreds (or thousands!) of specialized point-to-point interfaces for data flows / file transfers Documentation and tracking of these complex interfaces requires extensive time to develop and extremely high staffing costs Implementation and testing of these interfaces are even more cost-prohibitive, and documentation often lags behind implementation resulting in inconsistencies down the road With expanding threat vectors, IT Security, Information Assurance and Operational Security have become key Ground System architecture drivers New Federal security-related directives are generated on a daily basis, imposing new requirements on current / existing ground systems - These mandated activities and data calls typically carry little or no additional funding for implementation As a result, Ground System Sustaining Engineering groups and Information Technology staff continually struggle to keep up with the rolling tide of security Advancing security concerns and shrinking budgets are pushing these large stove-piped ground systems to begin sharing resources - I.e. Operational / SysAdmin staff, IT security baselines, architecture decisions or even networks / hosting infrastructure Refactoring these existing ground systems into multi-mission assets proves extremely challenging due to what is typically very tight coupling between legacy components As a result, many "Multi-Mission" ops. environments end up simply sharing compute resources and networks due to the difficulty of refactoring into true multi-mission systems Utilizing continuous integration / rapid system deployment technologies in conjunction with an open architecture messaging approach allows System Engineers and Architects to worry less about the low-level details of interfaces between components and configuration of systems GMSEC messaging is inherently designed to support multi-mission requirements, and allows components to aggregate data across multiple homogeneous or heterogeneous satellites or payloads - The highly-successful Goddard Science and Planetary Operations Control Center (SPOCC) utilizes GMSEC as the hub for it's automation and situational awareness capability Shifts focus towards getting GS to a final configuration-managed baseline, as well as multi-mission / big-picture capabilities that help increase situational awareness, promote cross-mission sharing and establish enhanced fleet management capabilities across all levels of the enterprise.

The Austrian UV monitoring network

NASA Astrophysics Data System (ADS)

Blumthaler, Mario; Klotz, Barbara; Schwarzmann, Michael; Schreder, Josef

2017-02-01

The Austrian UV Monitoring network is operational since 1998 providing a large data set of erythemally weighted UV irradiance recorded with broadband UV biometer at 12 stations distributed all over Austria. In order to obtain high quality data all biometer are recalibrated once a year, the detectors are checked regularly for humidity and quality control is done routinely. The collected data are processed and then published on the website http://www.uv-index.at where the UV-Index of all measurement sites is presented in near real time together with a map of the distribution of the UV-Index over Austria. These UV-Index data together with measurements of global radiation and ozone levels from OMI are used to study long term trends for the stations of the monitoring network. Neither for all weather conditions nor for clear sky conditions is a statistically significant trend found for the UV-Index (with one exception) and for ozone. Furthermore, the radiation amplification factor (RAF) is determined experimentally from the power law correlation between UV-Index and ozone level for the site Innsbruck (577 m above sea level, 47.26°N, 11.38°E) for 19°solar elevation. A value of 0.91 ± 0.05 is found for the RAF for clear sky days with low ground albedo and a value of 1.03 ± 0.08 for days with high ground albedo (snow cover).

Intelligence Applied to Air Vehicles

NASA Technical Reports Server (NTRS)

Rosen, Robert; Gross, Anthony R.; Fletcher, L. Skip; Zornetzer, Steven (Technical Monitor)

2000-01-01

The exponential growth in information technology has provided the potential for air vehicle capabilities that were previously unavailable to mission and vehicle designers. The increasing capabilities of computer hardware and software, including new developments such as neural networks, provide a new balance of work between humans and machines. This paper will describe several NASA projects, and review results and conclusions from ground and flight investigations where vehicle intelligence was developed and applied to aeronautical and space systems. In the first example, flight results from a neural network flight control demonstration will be reviewed. Using, a highly-modified F-15 aircraft, a NASA/Dryden experimental flight test program has demonstrated how the neural network software can correctly identify and respond to changes in aircraft stability and control characteristics. Using its on-line learning capability, the neural net software would identify that something in the vehicle has changed, then reconfigure the flight control computer system to adapt to those changes. The results of the Remote Agent software project will be presented. This capability will reduce the cost of future spacecraft operations as computers become "thinking" partners along with humans. In addition, the paper will describe the objectives and plans for the autonomous airplane program and the autonomous rotorcraft project. Technologies will also be developed.

Data fusion concept in multispectral system for perimeter protection of stationary and moving objects

NASA Astrophysics Data System (ADS)

Ciurapiński, Wieslaw; Dulski, Rafal; Kastek, Mariusz; Szustakowski, Mieczyslaw; Bieszczad, Grzegorz; Życzkowski, Marek; Trzaskawka, Piotr; Piszczek, Marek

2009-09-01

The paper presents the concept of multispectral protection system for perimeter protection for stationary and moving objects. The system consists of active ground radar, thermal and visible cameras. The radar allows the system to locate potential intruders and to control an observation area for system cameras. The multisensor construction of the system ensures significant improvement of detection probability of intruder and reduction of false alarms. A final decision from system is worked out using image data. The method of data fusion used in the system has been presented. The system is working under control of FLIR Nexus system. The Nexus offers complete technology and components to create network-based, high-end integrated systems for security and surveillance applications. Based on unique "plug and play" architecture, system provides unmatched flexibility and simplistic integration of sensors and devices in TCP/IP networks. Using a graphical user interface it is possible to control sensors and monitor streaming video and other data over the network, visualize the results of data fusion process and obtain detailed information about detected intruders over a digital map. System provides high-level applications and operator workload reduction with features such as sensor to sensor cueing from detection devices, automatic e-mail notification and alarm triggering.

The Design and Application of Data Storage System in Miyun Satellite Ground Station

NASA Astrophysics Data System (ADS)

Xue, Xiping; Su, Yan; Zhang, Hongbo; Liu, Bin; Yao, Meijuan; Zhao, Shu

2015-04-01

China has launched Chang'E-3 satellite in 2013, firstly achieved soft landing on moon for China's lunar probe. Miyun satellite ground station firstly used SAN storage network system based-on Stornext sharing software in Chang'E-3 mission. System performance fully meets the application requirements of Miyun ground station data storage.The Stornext file system is a sharing file system with high performance, supports multiple servers to access the file system using different operating system at the same time, and supports access to data on a variety of topologies, such as SAN and LAN. Stornext focused on data protection and big data management. It is announced that Quantum province has sold more than 70,000 licenses of Stornext file system worldwide, and its customer base is growing, which marks its leading position in the big data management.The responsibilities of Miyun satellite ground station are the reception of Chang'E-3 satellite downlink data and management of local data storage. The station mainly completes exploration mission management, receiving and management of observation data, and provides a comprehensive, centralized monitoring and control functions on data receiving equipment. The ground station applied SAN storage network system based on Stornext shared software for receiving and managing data reliable.The computer system in Miyun ground station is composed by business running servers, application workstations and other storage equipments. So storage systems need a shared file system which supports heterogeneous multi-operating system. In practical applications, 10 nodes simultaneously write data to the file system through 16 channels, and the maximum data transfer rate of each channel is up to 15MB/s. Thus the network throughput of file system is not less than 240MB/s. At the same time, the maximum capacity of each data file is up to 810GB. The storage system planned requires that 10 nodes simultaneously write data to the file system through 16 channels with 240MB/s network throughput.When it is integrated,sharing system can provide 1020MB/s write speed simultaneously.When the master storage server fails, the backup storage server takes over the normal service.The literacy of client will not be affected,in which switching time is less than 5s.The design and integrated storage system meet users requirements. Anyway, all-fiber way is too expensive in SAN; SCSI hard disk transfer rate may still be the bottleneck in the development of the entire storage system. Stornext can provide users with efficient sharing, management, automatic archiving of large numbers of files and hardware solutions. It occupies a leading position in big data management. Storage is the most popular sharing shareware, and there are drawbacks in Stornext: Firstly, Stornext software is expensive, in which charge by the sites. When the network scale is large, the purchase cost will be very high. Secondly, the parameters of Stornext software are more demands on the skills of technical staff. If there is a problem, it is difficult to exclude.

High Speed A/D DSP Interface for Carrier Doppler Tracking

NASA Technical Reports Server (NTRS)

Baggett, Timothy

1998-01-01

As on-board satellite systems continue to increase in ability to perform self diagnostic checks, it will become more important for satellites to initiate ground communications contact. Currently, the NASA Space Network requires users to pre-arranged times for satellite communications links through the Tracking and Data Relay Satellite (TDRS). One of the challenges in implementing an on-demand access protocol into the Space Network, is the fact that a low Earth orbiting (LEO) satellite's communications will be subject to a doppler shift which is outside the capability of the NASA ground station to lock onto. In a prearranged system, the satellite's doppler is known a priori, and the ground station is able to lock onto the satellite's signal. This paper describes the development of a high speed analog to digital interface into a Digital Signal Processor (DSP). This system will be used for identifying the doppler shift of a LEO satellite through the Space Network, and aiding the ground station equipment in locking onto the signal. Although this interface is specific to one application, it can be used as a basis for interfacing other devices with a DSP.

Power plant fault detection using artificial neural network

NASA Astrophysics Data System (ADS)

Thanakodi, Suresh; Nazar, Nazatul Shiema Moh; Joini, Nur Fazriana; Hidzir, Hidzrin Dayana Mohd; Awira, Mohammad Zulfikar Khairul

2018-02-01

The fault that commonly occurs in power plants is due to various factors that affect the system outage. There are many types of faults in power plants such as single line to ground fault, double line to ground fault, and line to line fault. The primary aim of this paper is to diagnose the fault in 14 buses power plants by using an Artificial Neural Network (ANN). The Multilayered Perceptron Network (MLP) that detection trained utilized the offline training methods such as Gradient Descent Backpropagation (GDBP), Levenberg-Marquardt (LM), and Bayesian Regularization (BR). The best method is used to build the Graphical User Interface (GUI). The modelling of 14 buses power plant, network training, and GUI used the MATLAB software.

The total carbon column observing network.

PubMed

Wunch, Debra; Toon, Geoffrey C; Blavier, Jean-François L; Washenfelder, Rebecca A; Notholt, Justus; Connor, Brian J; Griffith, David W T; Sherlock, Vanessa; Wennberg, Paul O

2011-05-28

A global network of ground-based Fourier transform spectrometers has been founded to remotely measure column abundances of CO(2), CO, CH(4), N(2)O and other molecules that absorb in the near-infrared. These measurements are directly comparable with the near-infrared total column measurements from space-based instruments. With stringent requirements on the instrumentation, acquisition procedures, data processing and calibration, the Total Carbon Column Observing Network (TCCON) achieves an accuracy and precision in total column measurements that is unprecedented for remote-sensing observations (better than 0.25% for CO(2)). This has enabled carbon-cycle science investigations using the TCCON dataset, and allows the TCCON to provide a link between satellite measurements and the extensive ground-based in situ network. © 2011 The Royal Society

Quality of ground water used for public supply in Florida, 1983-84

USGS Publications Warehouse

Irwin, G.A.; Kirkland, R.T.; Pruitt, J.B.

1985-01-01

From October 1983 through March 1984, a chemical sampling reconnaissance was made of ground water used for public supply for 91 communities throughout Florida. Public supply wells present an excellent network for collecting baseline water-quality information on the quality of ground water prior to any treatment because they are located throughout the State, are in the most populated areas, usually have continuous and often high pumpage, and have great health and economic significance. The reconnaissance was part of several project tasks sponsored by the Florida Department of Environmental Regulation to develop guidelines and data bases for use in the design and implementation of a statewide ground-water monitoring network as mandated by the recent enactment of Florida 's Water Quality Assurance Act of 1983. (USGS)

Determination of trajectories of fireballs using seismic network data

NASA Astrophysics Data System (ADS)

Ishihara, Y.

2006-12-01

Fireballs, Bolides, which are caused by high velocity passages of meteoroids through the atmosphere, generate shockwaves. Meteor shockwave provide us very important information (arrival time and amplitude) to study meteor physics. The shockwave arrival time data enable us to determine trajectories of the fireballs. On the other hand, the shockwave amplitude tells us size and ablation history of the meteoroid. Infrasound observation is one of the ways of detecting bolide shockwaves. However, we have no infrasound observational networks extends for large area with enough spatial distribution for determination of trajectories and estimate ablation histories. We have only a few infrasound arrays that have three or four elements, in the Japanese islands. Last decade, digital seismic networks are greatly improved for the purpose of monitoring micro earthquakes. Those seismic networks are quite sensitive for detecting micro ground vibration, and then those networks could detect not only seismic wave generated by earthquakes, but also ground oscillations generated by coupling of meteor shockwave with the ground near station. Last years, I analyses this kind of ground motion data recorded by seismic network, as meteor shockwave signals. For example, we estimate some great fireball's aerial path from arrival times of shockwaves (e.g., Ishihara et. al., 2003 Earth Planets, and Space, 2004 Geophysical Research. Letters.; Pujol et al., 2006 Planetary and Space Science), and we estimate sizes and ablation history of some great fireball and a meteorite fall (Ishihara et al., 2004 Meteoroids2004). In Japan, some great fireball falls occurred during 2004 to 2005. In this presentation, I show the trajectories of these fireballs determined from shockwave analysis. Some fireballs trajectories are also determined from photographic records. The trajectories determined from shockwave and that from photos show good agreement.

The DRAGON scale concept and results for remote sensing of aerosol properties

NASA Astrophysics Data System (ADS)

Holben, B. N.; Eck, T. F.; Schafer, J.; Giles, D. M.; Kim, J.; Sano, I.; Mukai, S.; Kim, Y. J.; Reid, J. S.; Pickering, K. E.; Crawford, J. H.; Smirnov, A.; Sinyuk, A.; Slutsker, I.; Sorokin, M.; Rodriguez, J.; Liew, S.; Trevino, N.; Lim, H.; Lefer, B. L.; Nadkarni, R.; Macke, A.; Kinne, S. A.; Anderson, B. E.; Russell, P. B.; Maring, H. B.; Welton, E. J.; da Silva, A.; Toon, O. B.; Redemann, J.

2013-12-01

Aerosol processes occur at microscales but are typically observed and reported at continental to global scales. Often observable aerosol processes that have significant anthropogenic impact occur on spatial scales of tens to a few hundred km, representative of convective cloud processing, urban/megacity sources, anthropogenic burning and natural wildfires, dry lakebed dust sources etc. Historically remote sensing of aerosols has relied on relatively coarse temporal and spatial resolution satellite observations or high temporal resolution point observations from ground-based monitoring sites from networks such as AERONET, SKYNET, MPLNET and many other surface observation platforms. Airborne remote and in situ observations combined with assimilation models were/are to be the mesoscale link between the ground- and space-based RS scales. However clearly the in situ and ground-based RS characterizations of aerosols require a convergence of thought, parameterization and actual scale measurements in order to advance this goal. This has been served by periodic multidisciplinary field campaigns yet only recently has a concerted effort been made to establish these ground-based networks in an effort to capture the mesoscale processes through measurement programs such as DISCOVER AQ and NASA AERONET's effort to foster such measurements and analysis through the Distributed Regional Aerosol Gridded Observation Networks (DRAGON), short term meso-networks, with partners in Asia and Europe and N. America. This talk will review the historical need for such networks and discuss some of the results and in some cases unexpected findings from the eight DRAGON campaigns conducted the last several years. Emphasis will be placed on the most recent DISCOVER AQ campaign conducted in Houston TX and the synergism with a regional to global network plan through the SEAC4RS US campaign.

Ramification of Channel Networks Incised by Groundwater Flow

NASA Astrophysics Data System (ADS)

Yi, R. S.; Seybold, H. F.; Petroff, A. P.; Devauchelle, O.; Rothman, D.

2011-12-01

The geometry of channel networks has been a source of fascination since at least Leonardo da Vinci's time. Yet a comprehensive understanding of ramification---the mechanism of branching by which a stream network acquires its geometric complexity---remains elusive. To investigate the mechanisms of ramification and network growth, we consider channel growth driven by groundwater flow as a model system, analogous to a medical scientist's laboratory rat. We test our theoretical predictions through analysis of a particularly compelling example found on the Florida Panhandle north of Bristol. As our ultimate goal is to understand ramification and growth dynamics of the entire network, we build a computational model based on the following growth hypothesis: Channels grow in the direction that captures the maximum water flux. When there are two such directions, tips bifurcate. The direction of growth can be determined from the expansion of the ground water field around each tip, where each coefficient in this expansion has a physical interpretation. The first coefficient in the expansion determines the ground water discharge, leading to a straight growth of the channel. The second term describes the asymmetry in the water field leading to a bending of the stream in the direction of maximal water flux. The ratio between the first and the third coefficient determines a critical distance rc over which the tip feels inhomogeneities in the ground water table. This initiates then the splitting of the tip. In order to test our growth hypothesis and to determine rc, we grow the Florida network backward. At each time step we calculate the solution of the ground water field and determine the appropriate expansion coefficients around each tip. Comparing this simulation result to the predicted values provides us with a stringent measure for rc and the significance of our growth hypothesis.

Arabidopsis JACKDAW and MAGPIE zinc finger proteins delimit asymmetric cell division and stabilize tissue boundaries by restricting SHORT-ROOT action

PubMed Central

Welch, David; Hassan, Hala; Blilou, Ikram; Immink, Richard; Heidstra, Renze; Scheres, Ben

2007-01-01

In the Arabidopsis root, the SHORT-ROOT transcription factor moves outward to the ground tissue from its site of transcription in the stele and is required for the specification of the endodermis and the stem cell organizing quiescent center cells. In addition, SHORT-ROOT and the downstream transcription factor SCARECROW control an oriented cell division in ground tissue stem cell daughters. Here, we show that the JACKDAW and MAGPIE genes, which encode members of a plant-specific family of zinc finger proteins, act in a SHR-dependent feed-forward loop to regulate the range of action of SHORT-ROOT and SCARECROW. JACKDAW expression is initiated independent of SHORT-ROOT and regulates the SCARECROW expression domain outside the stele, while MAGPIE expression depends on SHORT-ROOT and SCARECROW. We provide evidence that JACKDAW and MAGPIE regulate tissue boundaries and asymmetric cell division and can control SHORT-ROOT and SCARECROW activity in a transcriptional and protein interaction network. PMID:17785527

A ground-water-quality monitoring program for Nevada

USGS Publications Warehouse

Nowlin, Jon O.

1986-01-01

A program was designed for the systematic monitoring of ground-water quality in Nevada. Basic hydrologic and water-quality principles are discussed in the formulation of a rational approach to developing a statewide monitoring program. A review of ground-water monitoring efforts in Nevada through 1977 indicates that few requirements for an effective statewide program are being met. A suggested program has been developed that consists of five major elements: (1) A Background-Quality Network to assess the existing water quality in Nevada aquifers, (2) a Contamination Source Inventory of known or potential threats to ground-water quality, (3) Surveillance Networks to monitor ground-water quality in selected hydrographic areas, (4) Intensive Surveys of individual instances of known or potential ground-water contamination, and (5) Ground-Water Data File to manage data generated by the other monitoring elements. Two indices have been developed to help assign rational priorities for monitoring ground water in the 255 hydrographic areas of Nevada: (1) A Hydrographic-Area Priority Index for surveillance monitoring, and (2) A Development-Potential Index for background monitoring of areas with little or no current development. Requirements for efficient management of data from ground-water monitoring are discussed and the three major systems containing Nevada ground-water data are reviewed. More than 11,000 chemical analyses of ground water have been acquired from existing systems and incorporated into a prototype data base.

Nodes

NASA Technical Reports Server (NTRS)

Hanson, John; Martinez, Andres; Petro, Andrew

2015-01-01

Nodes is a technology demonstration mission that is scheduled for launch to the International SpaceStation no earlier than Nov.19, 2015. The two Nodes satellites will be deployed from the Station in early 2016 todemonstrate new network capabilities critical to the operation of swarms of spacecraft. They will demonstrate the ability ofmulti spacecraft swarms to receive and distribute ground commands, exchange information periodically, andautonomously configure the network by determining which spacecraft should communicate with the ground each day ofthe mission.

Toward implementation of a national ground water monitoring network

USGS Publications Warehouse

Schreiber, Robert P.; Cunningham, William L.; Copeland, Rick; Frederick, Kevin D.

2008-01-01

The Federal Advisory Committee on Water Information's (ACWI) Subcommittee on Ground Water (SOGW) has been working steadily to develop and encourage implementation of a nationwide, long-term ground-water quantity and quality monitoring framework. Significant progress includes the planned submission this fall of a draft framework document to the full committee. The document will include recommendations for implementation of the network and continued acknowledgment at the federal and state level of ACWI's potential role in national monitoring toward an improved assessment of the nation's water reserves. The SOGW mission includes addressing several issues regarding network design, as well as developing plans for concept testing, evaluation of costs and benefits, and encouraging the movement from pilot-test results to full-scale implementation within a reasonable time period. With the recent attention to water resource sustainability driven by severe droughts, concerns over global warming effects, and persistent water supply problems, the SOGW mission is now even more critical.

Integrating wireless sensor network for monitoring subsidence phenomena

NASA Astrophysics Data System (ADS)

Marturià, Jordi; Lopez, Ferran; Gigli, Giovanni; Intrieri, Emanuele; Mucchi, Lorenzo; Fornaciai, Alessandro

2016-04-01

An innovative wireless sensor network (WSN) for the 3D superficial monitoring of deformations (such as landslides and subsidence) is being developed in the frame of the Wi-GIM project (Wireless sensor network for Ground Instability Monitoring - LIFE12 ENV/IT/001033). The surface movement is detected acquiring the position (x, y and z) by integrating large bandwidth technology able to detect the 3D coordinates of the sensor with a sub-meter error, with continuous wave radar, which allows decreasing the error down to sub-cm. The Estació neighborhood in Sallent is located over the old potassium mine Enrique. This zone has been affected by a subsidence process over more than twenty years. The implementation of a wide network for ground auscultation has allowed monitoring the process of subsidence since 1997. This network consists of: i) a high-precision topographic leveling network to control the subsidence in surface; ii) a rod extensometers network to monitor subsurface deformation; iii) an automatic Leica TCA Total Station to monitor building movements; iv) an inclinometers network to measure the horizontal displacements on subsurface and v) a piezometer to measure the water level. Those networks were implemented within an alert system for an organized an efficient response of the civil protection authorities in case of an emergency. On 23rd December 2008, an acceleration of subsoil movements (of approx. 12-18 cm/year) provoked the activation of the emergency plan by the Catalan Civil Protection. This implied the preventive and scheduled evacuation of the neighbours (January 2009) located in the area with a higher risk of collapse: around 120 residents of 43 homes. As a consequence, the administration implemented a compensation plan for the evacuation of the whole neighbourhood residents and the demolition of 405 properties. In this work, the adaptation and integration process of Wi-GIM system with those conventional monitoring network are presented for its testing and evaluation. The knowledge gained in the subsidence process, complemented by the huge availability of data from existing networks constitutes a solid foundation for achieving those objectives. New monitoring points have been identified, constructed, prepared to integrate the conventional monitoring system with Wi-GIM system to build a robust system compatible with WI-GIM requirements.

The Impact of Satellites on Cable Communications.

ERIC Educational Resources Information Center

Chayes, Abram

Two recent developments in communications satellite technology may speed the coming of cable TV (CATV) networks. First, increases in satellite power are reducing the cost of ground stations. Second, a connection between one ground station, the satellite, and any other ground station is no longer necessarily fixed. Now one station can communicate…

The American mobile satellite system

NASA Technical Reports Server (NTRS)

Garner, William B.

1990-01-01

During 1989, the American Mobile Satellite Corporation (AMSC) was authorized to construct, launch, and operate satellites to provide mobile satellite services (MSS) to the U.S. and Puerto Rico. The AMSC has undertaken three major development programs to bring a full range of MSS services to the U.S. The first program is the space segment program that will result in the construction and launch of the satellites as well as the construction and installation of the supporting ground telemetry and command system. The second segment will result in the specification, design, development, construction, and installation of the Network Control System necessary for managing communications access to the satellites, and the specification and development of ground equipment for standard circuit switched and packet switched communications services. The third program is the Phase 1 program to provide low speed data services within the U.S. prior to availability of the AMSC satellites and ground segment. Described here are the present status and plans for these three programs as well as an update on related business arrangements and regulatory matters.

A Statewide Private Microwave Wide Area Network for Real-time Natural Hazard Monitoring

NASA Astrophysics Data System (ADS)

Williams, M. C.; Kent, G.; Smith, K. D.; Plank, G.; Slater, D.; Torrisi, J.; Presser, R.; Straley, K.

2013-12-01

The Nevada Seismological Laboratory (NSL) at the University of Nevada, Reno, operates the Nevada Seismic Network, a collection of ground motion instruments installed throughout Nevada and California, for the purposes of detecting, locating, and notifying the public of earthquakes in the state. To perform these tasks effectively, NSL has designed and built a statewide wireless microwave wide-area network (WAN) in order to receive ground motion data in near real-time. This network consists of radio access points, backhauls, and backbone communication sites transmitting time-series, images, and datalogger diagnostics to our data center servers in Reno. This privately managed communication network greatly reduces the dependence on third-party infrastructure (e.g. commercial cellular networks), and is vital for emergency management response and system uptime. Any individual seismograph or data collection device is networked through a wireless point-to-multipoint connection to a remote access point (AP) using a low-cost radio/routerboard combination. Additional point-to-point connections from AP's to radio backhauls and/or mountaintop backbone sites allow the Data Center in Reno to communicate with and receive data directly from each datalogger. Dataloggers, radios, and routers can be configured using tablets on-site, or via desktop computers at the Data Center. Redundant mountaintop links can be added to the network and facilitate the re-routing of data (similar to a meshed network) in the event of a faulty, failing, or noisy communication site. All routers, radios, and servers, including those at the Data Center, have redundant power and can operate independently in the event of a grid power or public Internet outage. A managed server room at the Data Center processes earthquake data for notifications and acts as a data source for remote users. Consisting of about 500 hosts, and spanning hundreds of miles, this WAN provides network operators access to each router and datalogger in our seismic network not only for data collection, but also for maintenance and quality control. This has resulted in several partnerships with other agencies. In addition to our seismic station network for earthquake monitoring, we currently manage ~400 more channels of data (many running at 500 Hz) for the National Center for Nuclear Security (NCNS) Source Physics Experiments, a series of chemical explosions at the Nevada National Security Site. Some of our mountaintop stations have been experimentally equipped with near-infrared high-definition fire cameras for wildfire monitoring, and have recently recorded the Bison and Pedlar fires in northwest Nevada. Data for the Nevada EPSCor climate program also utilizes the NSL WAN. Real-time access to data for these experiments greatly reduces the effort required for data archival, quality control, and monitoring equipment failures. Future plans include increasing density of stations in urban areas such as Reno and Las Vegas, and expanding coverage to Tahoe and eastern Nevada.

Spatial prediction of ground subsidence susceptibility using an artificial neural network.

PubMed

Lee, Saro; Park, Inhye; Choi, Jong-Kuk

2012-02-01

Ground subsidence in abandoned underground coal mine areas can result in loss of life and property. We analyzed ground subsidence susceptibility (GSS) around abandoned coal mines in Jeong-am, Gangwon-do, South Korea, using artificial neural network (ANN) and geographic information system approaches. Spatial data of subsidence area, topography, and geology, as well as various ground-engineering data, were collected and used to create a raster database of relevant factors for a GSS map. Eight major factors causing ground subsidence were extracted from the existing ground subsidence area: slope, depth of coal mine, distance from pit, groundwater depth, rock-mass rating, distance from fault, geology, and land use. Areas of ground subsidence were randomly divided into a training set to analyze GSS using the ANN and a test set to validate the predicted GSS map. Weights of each factor's relative importance were determined by the back-propagation training algorithms and applied to the input factor. The GSS was then calculated using the weights, and GSS maps were created. The process was repeated ten times to check the stability of analysis model using a different training data set. The map was validated using area-under-the-curve analysis with the ground subsidence areas that had not been used to train the model. The validation showed prediction accuracies between 94.84 and 95.98%, representing overall satisfactory agreement. Among the input factors, "distance from fault" had the highest average weight (i.e., 1.5477), indicating that this factor was most important. The generated maps can be used to estimate hazards to people, property, and existing infrastructure, such as the transportation network, and as part of land-use and infrastructure planning.

Monitoring-well network and sampling design for ground-water quality, Wind River Indian Reservation, Wyoming

USGS Publications Warehouse

Mason, Jon P.; Sebree, Sonja K.; Quinn, Thomas L.

2005-01-01

The Wind River Indian Reservation, located in parts of Fremont and Hot Springs Counties, Wyoming, has a total land area of more than 3,500 square miles. Ground water on the Wind River Indian Reservation is a valuable resource for Shoshone and Northern Arapahoe tribal members and others who live on the Reservation. There are many types of land uses on the Reservation that have the potential to affect the quality of ground-water resources. Urban areas, rural housing developments, agricultural lands, landfills, oil and natural gas fields, mining, and pipeline utility corridors all have the potential to affect ground-water quality. A cooperative study was developed between the U.S. Geological Survey and the Wind River Environmental Quality Commission to identify areas of the Reservation that have the highest potential for ground-water contamination and develop a comprehensive plan to monitor these areas. An arithmetic overlay model for the Wind River Indian Reservation was created using seven geographic information system data layers representing factors with varying potential to affect ground-water quality. The data layers used were: the National Land Cover Dataset, water well density, aquifer sensitivity, oil and natural gas fields and petroleum pipelines, sites with potential contaminant sources, sites that are known to have ground-water contamination, and National Pollutant Discharge Elimination System sites. A prioritization map for monitoring ground-water quality on the Reservation was created using the model. The prioritization map ranks the priority for monitoring ground-water quality in different areas of the Reservation as low, medium, or high. To help minimize bias in selecting sites for a monitoring well network, an automated stratified random site-selection approach was used to select 30 sites for ground-water quality monitoring within the high priority areas. In addition, the study also provided a sampling design for constituents to be monitored, sampling frequency, and a simple water-table level observation well network.

High-Bandwidth Tactical-Network Data Analysis in a High-Performance-Computing (HPC) Environment: Packet-Level Analysis

DTIC Science & Technology

2015-09-01

with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS . 1...UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS (ES) Technical and Project Engineering, LLC QED Systems, LLC Alexandria, VA...AND ADDRESS (ES) US Army Research Laboratory ATTN: RDRL-CIH-C Aberdeen Proving Ground, MD 21005 10. SPONSOR/MONITOR’S ACRONYM(S) 11. SPONSOR

On-board Model Predictive Control of a Quadrotor Helicopter: Design, Implementation, and Experiments

DTIC Science & Technology

2012-12-13

speed, as the attached rotor effects momentum change of the surrounding air. However, we have in mind applications (e.g. mobile sensor networks... rotors is in play. At any rate, it suffices to note that the thrust from a given rotor is effectively proportional to its rate of rotation; indeed the...negligible impact on lift force when the main rotor is within 2 rotor diameters of the ground (Leishman, 2006). This effect has also been noted in other

IUS/TUG orbital operations and mission support study. Volume 4: Project planning data

NASA Technical Reports Server (NTRS)

1975-01-01

Planning data are presented for the development phases of interim upper stage (IUS) and tug systems. Major project planning requirements, major event schedules, milestones, system development and operations process networks, and relevant support research and technology requirements are included. Topics discussed include: IUS flight software; tug flight software; IUS/tug ground control center facilities, personnel, data systems, software, and equipment; IUS mission events; tug mission events; tug/spacecraft rendezvous and docking; tug/orbiter operations interface, and IUS/orbiter operations interface.

Non-Gimbaled Antenna Pointing: Summary of Results and Analysis

NASA Technical Reports Server (NTRS)

Horan, Stephen

1998-01-01

There is considerable interest at this time in developing small satellites for quick-turnaround missions to investigate near-earth phenomena from space. One problem to be solved in mission planning is the means of communication between the control infrastructure in the ground segment and the satellite in the space segment. A nominal small-satellite mission design often includes an omni-directional or similar wide-pattern antenna on the satellite and a dedicated ground station for telemetry, tracking, and command support. These terminals typically provide up to 15 minutes of coverage during an orbit that is within the visibility of the ground station; however, not all orbits will pass over the ground station so that coverage gaps will exist in the data flow. To overcome this general limitation on data transmission for low-earth orbiting satellites, the Space Network (SN), operated by the National Aeronautics and Space Administration, (NASA) has been designed to transmit data to and from user satellites through the Tracking and Data Relay Satellites (TDRS) in geostationary orbit and interfacing to the White Sands Complex (WSC) in New Mexico for the data's ground entry point. The advantage of the SN over a fixed ground station is that all low-earth-satellite orbits will be within the visibility area of at least one TDRS within the SN for a large part of the orbit and the potential exists to establish a communications link if the user satellite can point an antenna in the direction of any one of the relay satellites. Within NASA, there is considerable interest in seeing that small satellite developers are aware of the advantages to the SN and that designs to include the SN are part of the satellite design. Small satellite users have not often considered using the SN because of: (1) The 26-dB link penalty differential between direct broadcast to a ground station and transmission through a TDRS to the ground; (2) The class of satellite is too small to support high-gain antennas and associated attitude control and drive electronics; (3) The class of satellites is severely weight and power limited; (4) There are perceived problems in scheduling communications for this class of user on the SN. This report addresses the potential for SN access using non-gimbaled, i.e. fixed-pointed, antennas in the design of the small satellite using modest transmission power to achieve the necessary space-to-ground transmissions. The advantage of using the SN is in the reduction of mission costs arising from using the SN infrastructure instead of a dedicated, proprietary ground station using a similar type of communications package. From the simulations and analysis presented, we will show that a modest satellite configuration can be used with the space network to achieve the data transmission goals of a number of users and thereby rival the performance achieved with proprietary ground stations. In this study, we will concentrate on the return data link (from the user satellite through a TDRS to the ground data entry point). The forward command link (from the ground data entry point through a TDRS to the user satellite) will usually be a lower data rate service and the data volume will also be considerably lower than the return link's requirement. Therefore, we assume that if the return link requirements are satisfied, then the forward link requirements can also be satisfied.

Experience with Delay-Tolerant Networking from Orbit

NASA Technical Reports Server (NTRS)

Ivancic, W.; Eddy, W. M.; Stewart, D.; Wood, L.; Northam, J.; Jackson, C.

2010-01-01

We describe the first use from space of the Bundle Protocol for Delay-Tolerant Networking (DTN) and lessons learned from experiments made and experience gained with this protocol. The Disaster Monitoring Constellation (DMC), constructed by Surrey Satellite Technology Ltd (SSTL), is a multiple-satellite Earth-imaging low-Earth-orbit sensor network in which recorded image swaths are stored onboard each satellite and later downloaded from the satellite payloads to a ground station. Store-and-forward of images with capture and later download gives each satellite the characteristics of a node in a disruption-tolerant network. Originally developed for the Interplanetary Internet, DTNs are now under investigation in an Internet Research Task Force (IRTF) DTN research group (RG), which has developed a bundle architecture and protocol. The DMC is technically advanced in its adoption of the Internet Protocol (IP) for its imaging payloads and for satellite command and control, based around reuse of commercial networking and link protocols. These satellites use of IP has enabled earlier experiments with the Cisco router in Low Earth Orbit (CLEO) onboard the constellation s UK-DMC satellite. Earth images are downloaded from the satellites using a custom IP-based high-speed transfer protocol developed by SSTL, Saratoga, which tolerates unusual link environments. Saratoga has been documented in the Internet Engineering Task Force (IETF) for wider adoption. We experiment with the use of DTNRG bundle concepts onboard the UK-DMC satellite, by examining how Saratoga can be used as a DTN convergence layer to carry the DTNRG Bundle Protocol, so that sensor images can be delivered to ground stations and beyond as bundles. Our practical experience with the first successful use of the DTNRG Bundle Protocol in a space environment gives us insights into the design of the Bundle Protocol and enables us to identify issues that must be addressed before wider deployment of the Bundle Protocol. Published in 2010 by John Wiley & Sons, Ltd. KEY WORDS: Internet; UK-DMC; satellite; Delay-Tolerant Networking (DTN); Bundle Protocol

Characterisation of hydrogeological connections in a lowland karst network using time series analysis of water levels in ephemeral groundwater-fed lakes (turloughs)

NASA Astrophysics Data System (ADS)

Gill, L. W.; Naughton, O.; Johnston, P. M.; Basu, B.; Ghosh, B.

2013-08-01

This research has used continuous water level measurements five groundwater-fed lakes (or turloughs) in a linked lowland karst network of south Galway in Ireland over a 3 year period in order to elucidate the hydrogeological controls and conduit configurations forming the flooded karstic hydraulic system beneath the ground. The main spring outflow from this network discharges below mean sea level making it difficult to determine the hydraulic nature of the network using traditional rainfall-spring flow cross analysis, as has been done in many other studies on karst systems. However, the localised groundwater-surface water interactions (the turloughs) in this flooded lowland karst system can yield information about the nature of the hydraulic connections beneath the ground. Various different analytical techniques have been applied to the fluctuating turlough water level time series data in order to determine the nature of the linkage between them as well as hydraulic pipe configurations at key points in order to improve the conceptual model of the overall karst network. Initially, simple cross correlations between the different turlough water levels were carried out applying different time lags. Frequency analysis of the signals was then carried out using Fast Fourier transform analysis and then both discrete and continuous wavelet analyses have been applied to the data sets to characterise these inherently non-stationary time-series of fluctuating water levels. The analysis has indicated which turloughs are on the main line conduit system and which are somewhat off-line, the relative size of the main conduit in the network including evidence of localised constrictions, as well as clearly showing the tidal influence on the water levels in the three lower turloughs at shallow depths ∼8 km from the main spring outfall at the sea. It has also indicated that the timing of high rainfall events coincident with maximum spring tide levels may promote more consistent, long duration flooding of the turloughs throughout the winter.

Lattice Boltzmann simulation of CO2 reactive transport in network fractured media

NASA Astrophysics Data System (ADS)

Tian, Zhiwei; Wang, Junye

2017-08-01

Carbon dioxide (CO2) geological sequestration plays an important role in mitigating CO2 emissions for climate change. Understanding interactions of the injected CO2 with network fractures and hydrocarbons is key for optimizing and controlling CO2 geological sequestration and evaluating its risks to ground water. However, there is a well-known, difficult process in simulating the dynamic interaction of fracture-matrix, such as dynamic change of matrix porosity, unsaturated processes in rock matrix, and effect of rock mineral properties. In this paper, we develop an explicit model of the fracture-matrix interactions using multilayer bounce-back treatment as a first attempt to simulate CO2 reactive transport in network fractured media through coupling the Dardis's LBM porous model for a new interface treatment. Two kinds of typical fracture networks in porous media are simulated: straight cross network fractures and interleaving network fractures. The reaction rate and porosity distribution are illustrated and well-matched patterns are found. The species concentration distribution and evolution with time steps are also analyzed and compared with different transport properties. The results demonstrate the capability of this model to investigate the complex processes of CO2 geological injection and reactive transport in network fractured media, such as dynamic change of matrix porosity.

Development of Arduino based wireless control system

NASA Astrophysics Data System (ADS)

Sun, Zhuoxiong; Dyke, Shirley J.; Pena, Francisco; Wilbee, Alana

2015-03-01

Over the past few decades, considerable attention has been given to structural control systems to mitigate structural vibration under natural hazards such as earthquakes and extreme weather conditions. Traditional wired structural control systems often employ a large amount of cables for communication among sensors, controllers and actuators. In such systems, implementation of wired sensors is usually quite complicated and expensive, especially on large scale structures such as bridges and buildings. To reduce the laborious installation and maintenance cost, wireless control systems (WCSs) are considered as a novel approach for structural vibration control. In this work, a WCS is developed based on the open source Arduino platform. Low cost, low power wireless sensing and communication components are built on the Arduino platform. Structural control algorithms are embedded within the wireless sensor board for feedback control. The developed WCS is first validated through a series of tests. Next, numerical simulations are performed simulating wireless control of a 3-story shear structure equipped with a semi-active control device (MR damper). Finally, experimental studies are carried out implementing the WCS on the 3-story shear structure in the Intelligent Infrastructure Systems Lab (IISL). A hydraulic shake table is used to generate seismic ground motions. The control performance is evaluated with the impact of modeling uncertainties, measurement noises as well as time delay and data loss induced by the wireless network. The developed WCS is shown to be effective in controlling structural vibrations under several historical earthquake ground motions.

Building an Intelligent Water Information System - American River Prototype

NASA Astrophysics Data System (ADS)

Glaser, S. D.; Bales, R. C.; Conklin, M. H.

2013-12-01

With better management, California's existing water supplies could go further to meeting the needs of the state's urban and agricultural uses. For example, California's water reservoirs are currently controlled and regulated using forecasts based upon more than 75 years of historical data. In the face of global climate change, these forecasts are becoming increasingly inadequate to precisely manage water resources. We propose implementing Leveraging the newest frontiers of information technology, we are developing a basin-scale real-time intelligent water infrastructure system that enables more information-intensive decision support. The complete system is made up of four key components. First, a strategically deployed ground-observation system will complement satellite measurements and provide continuous and accurate estimates of snowpack, soil moisture, vegetation state and energy balance across watersheds. Using our recently developed but mature technologies, we deliver measurements of hydrologic variables over a multi- tiered network of wireless sensor arrays, with a granularity of time and space previously unheard of. Second, satellite and aircraft remote sensing provide the only practical means of spatially continuous basin-wide measurement and monitoring of snow properties, vegetation characteristics and other watershed conditions. The ground-based system is designed to blend with remote sensing data on Sierra Nevada snow properties, and provide value-added products of unprecedented spatial detail and accuracy that are useable on a watershed level. Third, together the satellite and ground-based data make possible the updating of forecast tools, and routine use of physically based hydrologic models. The decision-support framework will provide tools to extract and visualize information of interest from the measured and modeled data, to assess uncertainties, and to optimize operations. Fourth, the advanced cyber infrastructure blends and transforms the numbers recorded by sensors into information in the form that is useful for decision-making. In a sense it 'monetizes' the data. It is the cyber infrastructure that links measurements, data processing, models and users. System software must provide flexibility for multiple types of access from user queries to automated and direct links with analysis tools and decision-support systems. We are currently installing a basin-scale ground-based sensor network focusing on measurements of snowpack, solar radiation, temperature, rH and soil moisture across the American River basin. Although this is a research network, it also provides core elements of a full ground-based operational system.

Prototype of NASA's Global Precipitation Measurement Mission Ground Validation System

NASA Technical Reports Server (NTRS)

Schwaller, M. R.; Morris, K. R.; Petersen, W. A.

2007-01-01

NASA is developing a Ground Validation System (GVS) as one of its contributions to the Global Precipitation Mission (GPM). The GPM GVS provides an independent means for evaluation, diagnosis, and ultimately improvement of GPM spaceborne measurements and precipitation products. NASA's GPM GVS consists of three elements: field campaigns/physical validation, direct network validation, and modeling and simulation. The GVS prototype of direct network validation compares Tropical Rainfall Measuring Mission (TRMM) satellite-borne radar data to similar measurements from the U.S. national network of operational weather radars. A prototype field campaign has also been conducted; modeling and simulation prototypes are under consideration.

Inmarsat aeronautical mobile satellite system: Internetworking issues

NASA Technical Reports Server (NTRS)

Sengupta, Jay R.

1990-01-01

The Inmarsat Aeronautical Mobile Satellite System (AMSS) provides air-ground and air-air communications services to aero-mobile users on a global basis. Communicating parties may be connected either directly, or more commonly, via interconnecting networks to the Inmarsat AMSS, in order to construct end-to-end communications circuits. The aircraft earth station (AES) and the aeronautical ground earth station (GES) are the points of interconnection of the Inmarsat AMSS to users, as well as to interconnecting networks. This paper reviews the internetworking aspects of the Inmarsat AMSS, by introducing the Inmarsat AMSS network architecture and services concepts and then discussing the internetwork address/numbering and routing techniques.

The deep space network, volume 7

NASA Technical Reports Server (NTRS)

1972-01-01

The objectives, functions, and organization of the Deep Space Network are summarized. The Deep Space Instrumentation Facility, the Ground Communications Facility, and the Space Flight Operations Facility are described.

Integrated Network Architecture for Sustained Human and Robotic Exploration

NASA Technical Reports Server (NTRS)

Noreen, Gary; Cesarone, Robert; Deutsch, Leslie; Edwards, Charles; Soloff, Jason; Ely, Todd; Cook, Brian; Morabito, David; Hemmati, Hamid; Piazolla, Sabino;

Networked high-speed auroral observations combined with radar measurements for multi-scale insights

NASA Astrophysics Data System (ADS)

Hirsch, M.; Semeter, J. L.

2015-12-01

Networks of ground-based instruments to study terrestrial aurora for the purpose of analyzing particle precipitation characteristics driving the aurora have been established. Additional funding is pouring into future ground-based auroral observation networks consisting of combinations of tossable, portable, and fixed installation ground-based legacy equipment. Our approach to this problem using the High Speed Tomography (HiST) system combines tightly-synchronized filtered auroral optical observations capturing temporal features of order 10 ms with supporting measurements from incoherent scatter radar (ISR). ISR provides a broader spatial context up to order 100 km laterally on one minute time scales, while our camera field of view (FOV) is chosen to be order 10 km at auroral altitudes in order to capture 100 m scale lateral auroral features. The dual-scale observations of ISR and HiST fine-scale optical observations may be coupled through a physical model using linear basis functions to estimate important ionospheric quantities such as electron number density in 3-D (time, perpendicular and parallel to the geomagnetic field).Field measurements and analysis using HiST and PFISR are presented from experiments conducted at the Poker Flat Research Range in central Alaska. Other multiscale configuration candidates include supplementing networks of all-sky cameras such as THEMIS with co-locations of HiST-like instruments to fuse wide FOV measurements with the fine-scale HiST precipitation characteristic estimates. Candidate models for this coupling include GLOW and TRANSCAR. Future extensions of this work may include incorporating line of sight total electron count estimates from ground-based networks of GPS receivers in a sensor fusion problem.

The Telecommunications and Data Acquisition Report

NASA Technical Reports Server (NTRS)

Posner, E. C. (Editor)

1984-01-01

Developments in space communications, radio navigation, radio science, ground-base radio astronomy, reports on the Deep Space Network (DSN) and its Ground Communications Facility (GCF), and applications of radio interferometry at microwave frequencies are discussed.

Secure Autonomous Automated Scheduling (SAAS). Rev. 1.1

NASA Technical Reports Server (NTRS)

Walke, Jon G.; Dikeman, Larry; Sage, Stephen P.; Miller, Eric M.

2010-01-01

This report describes network-centric operations, where a virtual mission operations center autonomously receives sensor triggers, and schedules space and ground assets using Internet-based technologies and service-oriented architectures. For proof-of-concept purposes, sensor triggers are received from the United States Geological Survey (USGS) to determine targets for space-based sensors. The Surrey Satellite Technology Limited (SSTL) Disaster Monitoring Constellation satellite, the UK-DMC, is used as the space-based sensor. The UK-DMC's availability is determined via machine-to-machine communications using SSTL's mission planning system. Access to/from the UK-DMC for tasking and sensor data is via SSTL's and Universal Space Network's (USN) ground assets. The availability and scheduling of USN's assets can also be performed autonomously via machine-to-machine communications. All communication, both on the ground and between ground and space, uses open Internet standards

Investigations on the sensitivity of a stepped-frequency radar utilizing a vector network analyzer for Ground Penetrating Radar

NASA Astrophysics Data System (ADS)

Seyfried, Daniel; Schubert, Karsten; Schoebel, Joerg

2014-12-01

Employing a continuous-wave radar system, with the stepped-frequency radar being one type of this class, all reflections from the environment are present continuously and simultaneously at the receiver. Utilizing such a radar system for Ground Penetrating Radar purposes, antenna cross-talk and ground bounce reflection form an overall dominant signal contribution while reflections from objects buried in the ground are of quite weak amplitude due to attenuation in the ground. This requires a large dynamic range of the receiver which in turn requires high sensitivity of the radar system. In this paper we analyze the sensitivity of our vector network analyzer utilized as stepped-frequency radar system for GPR pipe detection. We furthermore investigate the performance of increasing the sensitivity of the radar by means of appropriate averaging and low-noise pre-amplification of the received signal. It turns out that the improvement in sensitivity actually achievable may differ significantly from theoretical expectations. In addition, we give a descriptive explanation why our appropriate experiments demonstrate that the sensitivity of the receiver is independent of the distance between the target object and the source of dominant signal contribution. Finally, our investigations presented in this paper lead to a preferred setting of operation for our vector network analyzer in order to achieve best detection capability for weak reflection amplitudes, hence making the radar system applicable for Ground Penetrating Radar purposes.

The GPM Ground Validation Program: Pre to Post-Launch

NASA Astrophysics Data System (ADS)

Petersen, W. A.

2014-12-01

NASA GPM Ground Validation (GV) activities have transitioned from the pre to post-launch era. Prior to launch direct validation networks and associated partner institutions were identified world-wide, covering a plethora of precipitation regimes. In the U.S. direct GV efforts focused on use of new operational products such as the NOAA Multi-Radar Multi-Sensor suite (MRMS) for TRMM validation and GPM radiometer algorithm database development. In the post-launch, MRMS products including precipitation rate, types and data quality are being routinely generated to facilitate statistical GV of instantaneous and merged GPM products. To assess precipitation column impacts on product uncertainties, range-gate to pixel-level validation of both Dual-Frequency Precipitation Radar (DPR) and GPM microwave imager data are performed using GPM Validation Network (VN) ground radar and satellite data processing software. VN software ingests quality-controlled volumetric radar datasets and geo-matches those data to coincident DPR and radiometer level-II data. When combined MRMS and VN datasets enable more comprehensive interpretation of ground-satellite estimation uncertainties. To support physical validation efforts eight (one) field campaigns have been conducted in the pre (post) launch era. The campaigns span regimes from northern latitude cold-season snow to warm tropical rain. Most recently the Integrated Precipitation and Hydrology Experiment (IPHEx) took place in the mountains of North Carolina and involved combined airborne and ground-based measurements of orographic precipitation and hydrologic processes underneath the GPM Core satellite. One more U.S. GV field campaign (OLYMPEX) is planned for late 2015 and will address cold-season precipitation estimation, process and hydrology in the orographic and oceanic domains of western Washington State. Finally, continuous direct and physical validation measurements are also being conducted at the NASA Wallops Flight Facility multi-radar, gauge and disdrometer facility located in coastal Virginia. This presentation will summarize the evolution of the NASA GPM GV program from pre to post-launch eras and highlight early evaluations of GPM satellite datasets.

A Multidisciplinary Approach to Assessing the Causal Components of Climate Change

NASA Astrophysics Data System (ADS)

Gosnold, W. D.; Todhunter, P. E.; Dong, X.; Rundquist, B.; Majorowicz, J.; Blackwell, D. D.

2004-05-01

Separation of climate forcing by anthropogenic greenhouse gases from natural radiative climate forcing is difficult because the composite temperature signal in the meteorological and multi-proxy temperature records cannot be resolved directly into radiative forcing components. To address this problem, we have initiated a large-scale, multidisciplinary project to test coherence between ground surface temperatures (GST) reconstructed from borehole T-z profiles, surface air temperatures (SAT), soil temperatures, and solar radiation. Our hypothesis is that radiative heating and heat exchange between the ground and the air directly control the ground surface temperature. Consequently, borehole T-z measurements at multi-year intervals spanning time periods when solar radiation, soil and air temperatures have been recorded should enable comparison of the thermal energy stored in the ground to these quantities. If coherence between energy storage, solar radiation, GST, SAT and multi-proxy temperature data can be discerned for a one or two decade scale, synthesis of GST and multi-proxy data over the past several centuries may enable us to separately determine the anthropogenic and natural forcings of climate change. The data we are acquiring include: (1) New T-z measurements in boreholes previously used in paleoclimate and heat flow research in Canada and the United States from the 1970's to the present. (2) Meteorological data from the US Historical Climatology Network and the Automated Weather Data Network of the High Plains Regional Climate Center, and Environment Canada. (3) Direct and remotely sensed data on land use, environment, and soil properties at selected borehole and meteorological sites for the periods between borehole observations. The project addresses three related questions: What is the coherence between the GST, SAT, soil temperatures and solar radiation? Have microclimate changes at borehole sites and climate stations affected temperature trends? If good coherence is obtained, can the coherence between thermal energy stored in the ground and radiative forcing during the time between T-z measurements be extended several centuries into the past?

Assessment of Water-Quality Monitoring and a Proposed Water-Quality Monitoring Network for the Mosquito Lagoon Basin, East-Central Florida

USGS Publications Warehouse

Kroening, Sharon E.

2008-01-01

Surface- and ground-water quality data from the Mosquito Lagoon Basin were compiled and analyzed to: (1) describe historical and current monitoring in the basin, (2) summarize surface- and ground-water quality conditions with an emphasis on identifying areas that require additional monitoring, and (3) develop a water-quality monitoring network to meet the goals of Canaveral National Seashore (a National Park) and to fill gaps in current monitoring. Water-quality data were compiled from the U.S. Environmental Protection Agency's STORET system, the U.S. Geological Survey's National Water Information System, or from the agency which collected the data. Most water-quality monitoring focused on assessing conditions in Mosquito Lagoon. Significant spatial and/or seasonal variations in water-quality constituents in the lagoon were quantified for pH values, fecal coliform bacteria counts, and concentrations of dissolved oxygen, total nitrogen, total phosphorus, chlorophyll-a, and total suspended solids. Trace element, pesticide, and ground-water-quality data were more limited. Organochlorine insecticides were the major class of pesticides analyzed. A surface- and ground-water-quality monitoring network was designed for the Mosquito Lagoon Basin which emphasizes: (1) analysis of compounds indicative of human activities, including pesticides and other trace organic compounds present in domestic and industrial waste; (2) greater data collection in the southern part of Mosquito Lagoon where spatial variations in water-quality constituents were quantified; and (3) additional ground-water-quality data collection in the surficial aquifer system and Upper Floridan aquifer. Surface-water-quality data collected as part of this network would include a fixed-station monitoring network of eight sites in the southern part of the basin, including a canal draining Oak Hill. Ground-water quality monitoring should be done routinely at about 20 wells in the surficial aquifer system and Upper Floridan aquifer, distributed between developed and undeveloped parts of the basin. Water samples collected should be analyzed for a wide range of constituents, including physical properties, nutrients, suspended sediment, and constituents associated with increased urban development such as pesticides, other trace organic compounds associated with domestic and industrial waste, and trace elements.

Ground states of partially connected binary neural networks

NASA Technical Reports Server (NTRS)

Baram, Yoram

1990-01-01

Neural networks defined by outer products of vectors over (-1, 0, 1) are considered. Patterns over (-1, 0, 1) define by their outer products partially connected neural networks consisting of internally strongly connected, externally weakly connected subnetworks. Subpatterns over (-1, 1) define subnetworks, and their combinations that agree in the common bits define permissible words. It is shown that the permissible words are locally stable states of the network, provided that each of the subnetworks stores mutually orthogonal subwords, or, at most, two subwords. It is also shown that when each of the subnetworks stores two mutually orthogonal binary subwords at most, the permissible words, defined as the combinations of the subwords (one corresponding to each subnetwork), that agree in their common bits are the unique ground states of the associated energy function.

Improving Air Quality Forecasts with AURA Observations

NASA Technical Reports Server (NTRS)

Newchurch, M. J.; Biazer, A.; Khan, M.; Koshak, W. J.; Nair, U.; Fuller, K.; Wang, L.; Parker, Y.; Williams, R.; Liu, X.

2008-01-01

Past studies have identified model initial and boundary conditions as sources of reducible errors in air-quality simulations. In particular, improving the initial condition improves the accuracy of short-term forecasts as it allows for the impact of local emissions to be realized by the model and improving boundary conditions improves long range transport through the model domain, especially in recirculating anticyclones. During the August 2006 period, we use AURA/OMI ozone measurements along with MODIS and CALIPSO aerosol observations to improve the initial and boundary conditions of ozone and Particulate Matter. Assessment of the model by comparison of the control run and satellite assimilation run to the IONS06 network of ozonesonde observations, which comprise the densest ozone sounding campaign ever conducted in North America, to AURA/TES ozone profile measurements, and to the EPA ground network of ozone and PM measurements will show significant improvement in the CMAQ calculations that use AURA initial and boundary conditions. Further analyses of lightning occurrences from ground and satellite observations and AURA/OMI NO2 column abundances will identify the lightning NOx signal evident in OMI measurements and suggest pathways for incorporating the lightning and NO2 data into the CMAQ simulations.

MIRAGE: The data acquisition, analysis, and display system

NASA Technical Reports Server (NTRS)

Rosser, Robert S.; Rahman, Hasan H.

1993-01-01

Developed for the NASA Johnson Space Center and Life Sciences Directorate by GE Government Services, the Microcomputer Integrated Real-time Acquisition Ground Equipment (MIRAGE) system is a portable ground support system for Spacelab life sciences experiments. The MIRAGE system can acquire digital or analog data. Digital data may be NRZ-formatted telemetry packets of packets from a network interface. Analog signal are digitized and stored in experimental packet format. Data packets from any acquisition source are archived to a disk as they are received. Meta-parameters are generated from the data packet parameters by applying mathematical and logical operators. Parameters are displayed in text and graphical form or output to analog devices. Experiment data packets may be retransmitted through the network interface. Data stream definition, experiment parameter format, parameter displays, and other variables are configured using spreadsheet database. A database can be developed to support virtually any data packet format. The user interface provides menu- and icon-driven program control. The MIRAGE system can be integrated with other workstations to perform a variety of functions. The generic capabilities, adaptability and ease of use make the MIRAGE a cost-effective solution to many experimental data processing requirements.

Emerging Needs for Pervasive Passive Wireless Sensor Networks on Aerospace Vehicles

NASA Technical Reports Server (NTRS)

Wilson, William C.; Juarez, Peter D.

2014-01-01

NASA is investigating passive wireless sensor technology to reduce instrumentation mass and volume in ground testing, air flight, and space exploration applications. Vehicle health monitoring systems (VHMS) are desired on all aerospace programs to ensure the safety of the crew and the vehicles. Pervasive passive wireless sensor networks facilitate VHMS on aerospace vehicles. Future wireless sensor networks on board aerospace vehicles will be heterogeneous and will require active and passive network systems. Since much has been published on active wireless sensor networks, this work will focus on the need for passive wireless sensor networks on aerospace vehicles. Several passive wireless technologies such as microelectromechanical systems MEMS, SAW, backscatter, and chipless RFID techniques, have all shown potential to meet the pervasive sensing needs for aerospace VHMS applications. A SAW VHMS application will be presented. In addition, application areas including ground testing, hypersonic aircraft and spacecraft will be explored along with some of the harsh environments found in aerospace applications.

U.S. EPA'S STRATEGY FOR GROUND WATER QUALITY MONITORING AT HAZARDOUS WASTE LAND DISPOSAL FACILITIES LOCATED IN KARST TERRANES

EPA Science Inventory

Ground water monitoring of hazardous waste land disposal units by a network of wells is ineffective when located in karstic terranes. The U.S. Environmental Protection Agency (EPA) is currently proposing to modify its current ground water quality monitoring requirement of one upg...

GLM Proxy Data Generation: Methods for Stroke/Pulse Level Inter-Comparison of Ground-Based Lightning Reference Networks

NASA Technical Reports Server (NTRS)

Cummins, Kenneth L.; Carey, Lawrence D.; Schultz, Christopher J.; Bateman, Monte G.; Cecil, Daniel J.; Rudlosky, Scott D.; Petersen, Walter Arthur; Blakeslee, Richard J.; Goodman, Steven J.

2011-01-01

In order to produce useful proxy data for the GOES-R Geostationary Lightning Mapper (GLM) in regions not covered by VLF lightning mapping systems, we intend to employ data produced by ground-based (regional or global) VLF/LF lightning detection networks. Before using these data in GLM Risk Reduction tasks, it is necessary to have a quantitative understanding of the performance of these networks, in terms of CG flash/stroke DE, cloud flash/pulse DE, location accuracy, and CLD/CG classification error. This information is being obtained through inter-comparison with LMAs and well-quantified VLF/LF lightning networks. One of our approaches is to compare "bulk" counting statistics on the spatial scale of convective cells, in order to both quantify relative performance and observe variations in cell-based temporal trends provided by each network. In addition, we are using microsecond-level stroke/pulse time correlation to facilitate detailed inter-comparisons at a more-fundamental level. The current development status of our ground-based inter-comparison and evaluation tools will be presented, and performance metrics will be discussed through a comparison of Vaisala s Global Lightning Dataset (GLD360) with the NLDN at locations within and outside the U.S.

GLM Proxy Data Generation: Methods for Stroke/Pulse Level Inter-comparison of Ground-based Lightning Reference Networks

NASA Astrophysics Data System (ADS)

Cummins, K. L.; Carey, L. D.; Schultz, C. J.; Bateman, M. G.; Cecil, D. J.; Rudlosky, S. D.; Petersen, W. A.; Blakeslee, R. J.; Goodman, S. J.

2011-12-01

In order to produce useful proxy data for the GOES-R Geostationary Lightning Mapper (GLM) in regions not covered by VLF lightning mapping systems, we intend to employ data produced by ground-based (regional or global) VLF/LF lightning detection networks. Before using these data in GLM Risk Reduction tasks, it is necessary to have a quantitative understanding of the performance of these networks, in terms of CG flash/stroke DE, cloud flash/pulse DE, location accuracy, and CLD/CG classification error. This information is being obtained through inter-comparison with LMAs and well-quantified VLF/LF lightning networks. One of our approaches is to compare "bulk" counting statistics on the spatial scale of convective cells, in order to both quantify relative performance and observe variations in cell-based temporal trends provided by each network. In addition, we are using microsecond-level stroke/pulse time correlation to facilitate detailed inter-comparisons at a more-fundamental level. The current development status of our ground-based inter-comparison and evaluation tools will be presented, and performance metrics will be discussed through a comparison of Vaisala's Global Lightning Dataset (GLD360) with the NLDN at locations within and outside the U.S.

Force-reflection and shared compliant control in operating telemanipulators with time delay

NASA Technical Reports Server (NTRS)

Kim, Won S.; Hannaford, Blake; Bejczy, Antal K.

1992-01-01

The performance of an advanced telemanipulation system in the presence of a wide range of time delays between a master control station and a slave robot is quantified. The contemplated applications include multiple satellite links to LEO, geosynchronous operation, spacecraft local area networks, and general-purpose computer-based short-distance designs. The results of high-precision peg-in-hole tasks performed by six test operators indicate that task performance decreased linearly with introduced time delays for both kinesthetic force feedback (KFF) and shared compliant control (SCC). The rate of this decrease was substantially improved with SCC compared to KFF. Task performance at delays above 1 s was not possible using KFF. SCC enabled task performance for such delays, which are realistic values for ground-controlled remote manipulation of telerobots in space.

A neural circuitry that emphasizes spinal feedback generates diverse behaviours of human locomotion

PubMed Central

Song, Seungmoon; Geyer, Hartmut

2015-01-01

Neural networks along the spinal cord contribute substantially to generating locomotion behaviours in humans and other legged animals. However, the neural circuitry involved in this spinal control remains unclear. We here propose a specific circuitry that emphasizes feedback integration over central pattern generation. The circuitry is based on neurophysiologically plausible muscle-reflex pathways that are organized in 10 spinal modules realizing limb functions essential to legged systems in stance and swing. These modules are combined with a supraspinal control layer that adjusts the desired foot placements and selects the leg that is to transition into swing control during double support. Using physics-based simulation, we test the proposed circuitry in a neuromuscular human model that includes neural transmission delays, musculotendon dynamics and compliant foot–ground contacts. We find that the control network is sufficient to compose steady and transitional 3-D locomotion behaviours including walking and running, acceleration and deceleration, slope and stair negotiation, turning, and deliberate obstacle avoidance. The results suggest feedback integration to be functionally more important than central pattern generation in human locomotion across behaviours. In addition, the proposed control architecture may serve as a guide in the search for the neurophysiological origin and circuitry of spinal control in humans. PMID:25920414

On-board fault diagnostics for fly-by-light flight control systems using neural network flight processors

NASA Astrophysics Data System (ADS)

Urnes, James M., Sr.; Cushing, John; Bond, William E.; Nunes, Steve

1996-10-01

Fly-by-Light control systems offer higher performance for fighter and transport aircraft, with efficient fiber optic data transmission, electric control surface actuation, and multi-channel high capacity centralized processing combining to provide maximum aircraft flight control system handling qualities and safety. The key to efficient support for these vehicles is timely and accurate fault diagnostics of all control system components. These diagnostic tests are best conducted during flight when all facts relating to the failure are present. The resulting data can be used by the ground crew for efficient repair and turnaround of the aircraft, saving time and money in support costs. These difficult to diagnose (Cannot Duplicate) fault indications average 40 - 50% of maintenance activities on today's fighter and transport aircraft, adding significantly to fleet support cost. Fiber optic data transmission can support a wealth of data for fault monitoring; the most efficient method of fault diagnostics is accurate modeling of the component response under normal and failed conditions for use in comparison with the actual component flight data. Neural Network hardware processors offer an efficient and cost-effective method to install fault diagnostics in flight systems, permitting on-board diagnostic modeling of very complex subsystems. Task 2C of the ARPA FLASH program is a design demonstration of this diagnostics approach, using the very high speed computation of the Adaptive Solutions Neural Network processor to monitor an advanced Electrohydrostatic control surface actuator linked through a AS-1773A fiber optic bus. This paper describes the design approach and projected performance of this on-line diagnostics system.

Optimized Autonomous Space In-situ Sensor-Web for volcano monitoring

USGS Publications Warehouse

Song, W.-Z.; Shirazi, B.; Kedar, S.; Chien, S.; Webb, F.; Tran, D.; Davis, A.; Pieri, D.; LaHusen, R.; Pallister, J.; Dzurisin, D.; Moran, S.; Lisowski, M.

2008-01-01

In response to NASA's announced requirement for Earth hazard monitoring sensor-web technology, a multidisciplinary team involving sensor-network experts (Washington State University), space scientists (JPL), and Earth scientists (USGS Cascade Volcano Observatory (CVO)), is developing a prototype dynamic and scaleable hazard monitoring sensor-web and applying it to volcano monitoring. The combined Optimized Autonomous Space -In-situ Sensor-web (OASIS) will have two-way communication capability between ground and space assets, use both space and ground data for optimal allocation of limited power and bandwidth resources on the ground, and use smart management of competing demands for limited space assets. It will also enable scalability and seamless infusion of future space and in-situ assets into the sensor-web. The prototype will be focused on volcano hazard monitoring at Mount St. Helens, which has been active since October 2004. The system is designed to be flexible and easily configurable for many other applications as well. The primary goals of the project are: 1) integrating complementary space (i.e., Earth Observing One (EO-1) satellite) and in-situ (ground-based) elements into an interactive, autonomous sensor-web; 2) advancing sensor-web power and communication resource management technology; and 3) enabling scalability for seamless infusion of future space and in-situ assets into the sensor-web. To meet these goals, we are developing: 1) a test-bed in-situ array with smart sensor nodes capable of making autonomous data acquisition decisions; 2) efficient self-organization algorithm of sensor-web topology to support efficient data communication and command control; 3) smart bandwidth allocation algorithms in which sensor nodes autonomously determine packet priorities based on mission needs and local bandwidth information in real-time; and 4) remote network management and reprogramming tools. The space and in-situ control components of the system will be integrated such that each element is capable of autonomously tasking the other. Sensor-web data acquisition and dissemination will be accomplished through the use of the Open Geospatial Consortium Sensorweb Enablement protocols. The three-year project will demonstrate end-to-end system performance with the in-situ test-bed at Mount St. Helens and NASA's EO-1 platform. ??2008 IEEE.

The verification of lightning location accuracy in Finland deduced from lightning strikes to trees

NASA Astrophysics Data System (ADS)

Mäkelä, Antti; Mäkelä, Jakke; Haapalainen, Jussi; Porjo, Niko

2016-05-01

We present a new method to determine the ground truth and accuracy of lightning location systems (LLS), using natural lightning strikes to trees. Observations of strikes to trees are being collected with a Web-based survey tool at the Finnish Meteorological Institute. Since the Finnish thunderstorms tend to have on average a low flash rate, it is often possible to identify from the LLS data unambiguously the stroke that caused damage to a given tree. The coordinates of the tree are then the ground truth for that stroke. The technique has clear advantages over other methods used to determine the ground truth. Instrumented towers and rocket launches measure upward-propagating lightning. Video and audio records, even with triangulation, are rarely capable of high accuracy. We present data for 36 quality-controlled tree strikes in the years 2007-2008. We show that the average inaccuracy of the lightning location network for that period was 600 m. In addition, we show that the 50% confidence ellipse calculated by the lightning location network and used operationally for describing the location accuracy is physically meaningful: half of all the strikes were located within the uncertainty ellipse of the nearest recorded stroke. Using tree strike data thus allows not only the accuracy of the LLS to be estimated but also the reliability of the uncertainty ellipse. To our knowledge, this method has not been attempted before for natural lightning.

A community detection algorithm using network topologies and rule-based hierarchical arc-merging strategies

PubMed Central

2017-01-01

The authors use four criteria to examine a novel community detection algorithm: (a) effectiveness in terms of producing high values of normalized mutual information (NMI) and modularity, using well-known social networks for testing; (b) examination, meaning the ability to examine mitigating resolution limit problems using NMI values and synthetic networks; (c) correctness, meaning the ability to identify useful community structure results in terms of NMI values and Lancichinetti-Fortunato-Radicchi (LFR) benchmark networks; and (d) scalability, or the ability to produce comparable modularity values with fast execution times when working with large-scale real-world networks. In addition to describing a simple hierarchical arc-merging (HAM) algorithm that uses network topology information, we introduce rule-based arc-merging strategies for identifying community structures. Five well-studied social network datasets and eight sets of LFR benchmark networks were employed to validate the correctness of a ground-truth community, eight large-scale real-world complex networks were used to measure its efficiency, and two synthetic networks were used to determine its susceptibility to two resolution limit problems. Our experimental results indicate that the proposed HAM algorithm exhibited satisfactory performance efficiency, and that HAM-identified and ground-truth communities were comparable in terms of social and LFR benchmark networks, while mitigating resolution limit problems. PMID:29121100

Serial Network Flow Monitor

NASA Technical Reports Server (NTRS)

Robinson, Julie A.; Tate-Brown, Judy M.

2009-01-01

Using a commercial software CD and minimal up-mass, SNFM monitors the Payload local area network (LAN) to analyze and troubleshoot LAN data traffic. Validating LAN traffic models may allow for faster and more reliable computer networks to sustain systems and science on future space missions. Research Summary: This experiment studies the function of the computer network onboard the ISS. On-orbit packet statistics are captured and used to validate ground based medium rate data link models and enhance the way that the local area network (LAN) is monitored. This information will allow monitoring and improvement in the data transfer capabilities of on-orbit computer networks. The Serial Network Flow Monitor (SNFM) experiment attempts to characterize the network equivalent of traffic jams on board ISS. The SNFM team is able to specifically target historical problem areas including the SAMS (Space Acceleration Measurement System) communication issues, data transmissions from the ISS to the ground teams, and multiple users on the network at the same time. By looking at how various users interact with each other on the network, conflicts can be identified and work can begin on solutions. SNFM is comprised of a commercial off the shelf software package that monitors packet traffic through the payload Ethernet LANs (local area networks) on board ISS.

A CDMA Spotbeam Architecture for the Next Generation Satellite System (NGSS) for the Aeronautical Telecommunications Network (ATN)

NASA Technical Reports Server (NTRS)

Raghavan, Rajesh S.; Shamma, Mohammed A.

2003-01-01

This paper will present work being done to model and simulate a CDMA based Mobile Satellite System architecture for providing all or part of the future Air Traffic Management (ATM) services. Such a system, will help in relieving the dependence on ground based networks, if not eliminate it. Additionally such an architecture can be used in parallel or as a supplementary service along with ground based links to help alleviate any capacity bottlenecks, or in areas where such services are difficult to make available such as in oceanic, remote areas outside the jet highways, or in developing countries where ground services are less available.

High Data Rate Architecture (HiDRA)

NASA Technical Reports Server (NTRS)

Hylton, Alan; Raible, Daniel

2016-01-01

One of the greatest challenges in developing new space technology is in navigating the transition from ground based laboratory demonstration at Technology Readiness Level 6 (TRL-6) to conducting a prototype demonstration in space (TRL-7). This challenge is com- pounded by the relatively low availability of new spacecraft missions when compared with aeronautical craft to bridge this gap, leading to the general adoption of a low-risk stance by mission management to accept new, unproven technologies into the system. Also in consideration of risk, the limited selection and availability of proven space-grade components imparts a severe limitation on achieving high performance systems by current terrestrial technology standards. Finally from a space communications point of view the long duration characteristic of most missions imparts a major constraint on the entire space and ground network architecture, since any new technologies introduced into the system would have to be compliant with the duration of the currently deployed operational technologies, and in some cases may be limited by surrounding legacy capabilities. Beyond ensuring that the new technology is verified to function correctly and validated to meet the needs of the end users the formidable challenge then grows to additionally include: carefully timing the maturity path of the new technology to coincide with a feasible and accepting future mission so it flies before its relevancy has passed, utilizing a limited catalog of available components to their maximum potential to create meaningful and unprecedented new capabilities, designing and ensuring interoperability with aging space and ground infrastructures while simultaneously providing a growth path to the future. The International Space Station (ISS) is approaching 20 years of age. To keep the ISS relevant, technology upgrades are continuously taking place. Regarding communications, the state-of-the-art communication system upgrades underway include high-rate laser terminals. These must interface with the existing, aging data infrastructure. The High Data Rate Architecture (HiDRA) project is designed to provide networked store, carry, and forward capability to optimize data flow through both the existing radio frequency (RF) and new laser communications terminal. The networking capability is realized through the Delay Tolerant Networking (DTN) protocol, and is used for scheduling data movement as well as optimizing the performance of existing RF channels. HiDRA is realized as a distributed FPGA memory and interface controller that is itself controlled by a local computer running DTN software. Thus HiDRA is applicable to other arenas seeking to employ next-generation communications technologies, e.g. deep space. In this paper, we describe HiDRA and its far-reaching research implications.

Cross Validation on the Equality of Uav-Based and Contour-Based Dems

NASA Astrophysics Data System (ADS)

Ma, R.; Xu, Z.; Wu, L.; Liu, S.

2018-04-01

Unmanned Aerial Vehicles (UAV) have been widely used for Digital Elevation Model (DEM) generation in geographic applications. This paper proposes a novel framework of generating DEM from UAV images. It starts with the generation of the point clouds by image matching, where the flight control data are used as reference for searching for the corresponding images, leading to a significant time saving. Besides, a set of ground control points (GCP) obtained from field surveying are used to transform the point clouds to the user's coordinate system. Following that, we use a multi-feature based supervised classification method for discriminating non-ground points from ground ones. In the end, we generate DEM by constructing triangular irregular networks and rasterization. The experiments are conducted in the east of Jilin province in China, which has been suffered from soil erosion for several years. The quality of UAV based DEM (UAV-DEM) is compared with that generated from contour interpolation (Contour-DEM). The comparison shows a higher resolution, as well as higher accuracy of UAV-DEMs, which contains more geographic information. In addition, the RMSE errors of the UAV-DEMs generated from point clouds with and without GCPs are ±0.5 m and ±20 m, respectively.

Photovoltaic Inverter Controllers Seeking AC Optimal Power Flow Solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dall'Anese, Emiliano; Dhople, Sairaj V.; Giannakis, Georgios B.

This paper considers future distribution networks featuring inverter-interfaced photovoltaic (PV) systems, and addresses the synthesis of feedback controllers that seek real- and reactive-power inverter setpoints corresponding to AC optimal power flow (OPF) solutions. The objective is to bridge the temporal gap between long-term system optimization and real-time inverter control, and enable seamless PV-owner participation without compromising system efficiency and stability. The design of the controllers is grounded on a dual ..epsilon..-subgradient method, while semidefinite programming relaxations are advocated to bypass the non-convexity of AC OPF formulations. Global convergence of inverter output powers is analytically established for diminishing stepsize rules formore » cases where: i) computational limits dictate asynchronous updates of the controller signals, and ii) inverter reference inputs may be updated at a faster rate than the power-output settling time.« less

Steerable Space Fed Lens Array for Low-Cost Adaptive Ground Station Applications

NASA Technical Reports Server (NTRS)

Lee, Richard Q.; Popovic, Zoya; Rondineau, Sebastien; Miranda, Felix A.

2007-01-01

The Space Fed Lens Array (SFLA) is an alternative to a phased array antenna that replaces large numbers of expensive solid-state phase shifters with a single spatial feed network. SFLA can be used for multi-beam application where multiple independent beams can be generated simultaneously with a single antenna aperture. Unlike phased array antennas where feed loss increases with array size, feed loss in a lens array with more than 50 elements is nearly independent of the number of elements, a desirable feature for large apertures. In addition, SFLA has lower cost as compared to a phased array at the expense of total volume and complete beam continuity. For ground station applications, both of these tradeoff parameters are not important and can thus be exploited in order to lower the cost of the ground station. In this paper, we report the development and demonstration of a 952-element beam-steerable SFLA intended for use as a low cost ground station for communicating and tracking of a low Earth orbiting satellite. The dynamic beam steering is achieved through switching to different feed-positions of the SFLA via a beam controller.

Automated Guideway Ground Transportation Network Simulation

DOT National Transportation Integrated Search

1975-08-01

The report discusses some automated guideway management problems relating to ground transportation systems and provides an outline of the types of models and algorithms that could be used to develop simulation tools for evaluating system performance....

Exploring Normalization and Network Reconstruction Methods using In Silico and In Vivo Models

EPA Science Inventory

Abstract: Lessons learned from the recent DREAM competitions include: The search for the best network reconstruction method continues, and we need more complete datasets with ground truth from more complex organisms. It has become obvious that the network reconstruction methods t...

ITC/USA/'82; Proceedings of the International Telemetering Conference, San Diego, CA, September 28-30, 1982

NASA Astrophysics Data System (ADS)

The topics studied are related to customer-designed integrated circuits and silicon foundries, systems applications, recent developments in airborne telemetry hardware, optical communications, theoretical applications, stored data systems, digital communications-satellites and other systems, antenna systems and technology, the AF satellite control network, modems, telemetry standards, NASA Deep Space Network operations, and modems applicable to range telemetry and range data relay. Aspects of communication interoperability and transmission standards are considered along with subjects of magnetic tape rec/rep theory and technology, a satellite command and control panel, a computer automated ground station, STS communications, cryptography, RF systems, sensor unique data recovery techniques, software applications, multiplexer-demuliplexer, microprocessor applications, and communication relays. Attention is given to the U.S. Federal data encryption standard (DES), the impact of channel errors on data compression, the effect of premodulation filters on bit error rate performance, and power efficient optical communications for space applications. For individual items see A84-32402 to A84-32456

Applying traditional signal processing techniques to social media exploitation for situational understanding

NASA Astrophysics Data System (ADS)

Abdelzaher, Tarek; Roy, Heather; Wang, Shiguang; Giridhar, Prasanna; Al Amin, Md. Tanvir; Bowman, Elizabeth K.; Kolodny, Michael A.

2016-05-01

Signal processing techniques such as filtering, detection, estimation and frequency domain analysis have long been applied to extract information from noisy sensor data. This paper describes the exploitation of these signal processing techniques to extract information from social networks, such as Twitter and Instagram. Specifically, we view social networks as noisy sensors that report events in the physical world. We then present a data processing stack for detection, localization, tracking, and veracity analysis of reported events using social network data. We show using a controlled experiment that the behavior of social sources as information relays varies dramatically depending on context. In benign contexts, there is general agreement on events, whereas in conflict scenarios, a significant amount of collective filtering is introduced by conflicted groups, creating a large data distortion. We describe signal processing techniques that mitigate such distortion, resulting in meaningful approximations of actual ground truth, given noisy reported observations. Finally, we briefly present an implementation of the aforementioned social network data processing stack in a sensor network analysis toolkit, called Apollo. Experiences with Apollo show that our techniques are successful at identifying and tracking credible events in the physical world.

Simultaneous and coordinated rotational switching of all molecular rotors in a network

DOE PAGES

Zhang, Y.; Kersell, H.; Stefak, R.; ...

2016-05-09

A range of artificial molecular systems have been created that can exhibit controlled linear and rotational motion. In the development of such systems, a key step is the addition of communication between molecules in a network. Here, we show that a two-dimensional array of dipolar molecular rotors can undergo simultaneous rotational switching by applying an electric field from the tip of a scanning tunnelling microscope. Several hundred rotors made from porphyrin-based double-decker complexes can be simultaneously rotated when in a hexagonal rotor network on a Cu(111) surface by applying biases above ±1 V at 80 K. The phenomenon is observedmore » only in a hexagonal rotor network due to the degeneracy of the ground state dipole rotational energy barrier of the system. Defects are essential to increase electric torque on the rotor network and to stabilize the switched rotor domains. At low biases and low initial rotator angles, slight reorientations of individual rotors can occur resulting in the rotator arms pointing in different directions. In conclusion, analysis reveals that the rotator arm directions here are not random, but are coordinated to minimize energy via cross talk among the rotors through dipolar interactions.« less

A National Strategy to Develop Pragmatic Clinical Trials Infrastructure

PubMed Central

Guise, Jeanne‐Marie; Dolor, Rowena J.; Meissner, Paul; Tunis, Sean; Krishnan, Jerry A.; Pace, Wilson D.; Saltz, Joel; Hersh, William R.; Michener, Lloyd; Carey, Timothy S.

2014-01-01

Abstract An important challenge in comparative effectiveness research is the lack of infrastructure to support pragmatic clinical trials, which compare interventions in usual practice settings and subjects. These trials present challenges that differ from those of classical efficacy trials, which are conducted under ideal circumstances, in patients selected for their suitability, and with highly controlled protocols. In 2012, we launched a 1‐year learning network to identify high‐priority pragmatic clinical trials and to deploy research infrastructure through the NIH Clinical and Translational Science Awards Consortium that could be used to launch and sustain them. The network and infrastructure were initiated as a learning ground and shared resource for investigators and communities interested in developing pragmatic clinical trials. We followed a three‐stage process of developing the network, prioritizing proposed trials, and implementing learning exercises that culminated in a 1‐day network meeting at the end of the year. The year‐long project resulted in five recommendations related to developing the network, enhancing community engagement, addressing regulatory challenges, advancing information technology, and developing research methods. The recommendations can be implemented within 24 months and are designed to lead toward a sustained national infrastructure for pragmatic trials. PMID:24472114

Study protocol--Indigenous Australian social networks and the impact on smoking policy and programs in Australia: protocol for a mixed-method prospective study.

PubMed

Maddox, Raglan; Davey, Rachel; Cochrane, Tom; Lovett, Ray; van der Sterren, Anke

2013-09-24

Tobacco use is the most preventable cause of morbidity and mortality in Australia. Comprehensive tobacco control has reduced smoking rates in Australia from approximately 34 per cent in 1980 to 15 per cent in 2010. However, 46 per cent of Aboriginal and Torres Strait Islander people (Indigenous Australians) smoke on a daily basis, more than double the rate of non-Indigenous Australians. The evidence of effective tobacco control strategies for Indigenous Australians is relatively scarce. The aim of this study is to (i) explore the influences of smoking in Indigenous Australian people and to (ii) help inform and evaluate a multi-component tobacco control strategy. The study aims to answer the following questions:--do individuals' social networks influence smoking behaviours;--is there an association between various social and cultural factors and being a smoker or non-smoker; and--does a multi-component tobacco control program impact positively on tobacco behaviours, attitudes and beliefs in Indigenous Australians. Our prospective study will use a mixed-method approach (qualitative and quantitative), including a pre- and post-test evaluation of a tobacco control initiative. The study will explore the social and cultural context underlying Indigenous Australian tobacco use and associated factors which influence smoking behaviour. Primary data will be collected via a panel survey, interviews and focus groups. Secondary data will include de-identified PBS items related to smoking and also data collected from the Quitlines call service. Network analysis will be used to assess whether social networks influence smoking behaviours. For the survey, baseline differences will be tested using chi(2) statistics for the categorical and dichotomous variables and t-tests for the continuous variables, where appropriate. Grounded theory will be used to analyse the interviews and focus groups. Local Aboriginal community controlled organisations will partner in the study. Our study will explore the key factors, including the influence of social networks, that impact on tobacco use and the extent to which smoking behaviours transcend networks within the Indigenous Australian community in the ACT. This will add to the evidence-base, identifying influential factors to tobacco use and the effectiveness and influence of a multi-component tobacco control strategy.

Study protocol - Indigenous Australian social networks and the impact on smoking policy and programs in Australia: protocol for a mixed-method prospective study

PubMed Central

2013-01-01

Background Tobacco use is the most preventable cause of morbidity and mortality in Australia. Comprehensive tobacco control has reduced smoking rates in Australia from approximately 34 per cent in 1980 to 15 per cent in 2010. However, 46 per cent of Aboriginal and Torres Strait Islander people (Indigenous Australians) smoke on a daily basis, more than double the rate of non-Indigenous Australians. The evidence of effective tobacco control strategies for Indigenous Australians is relatively scarce. The aim of this study is to (i) explore the influences of smoking in Indigenous Australian people and to (ii) help inform and evaluate a multi-component tobacco control strategy. The study aims to answer the following questions: - do individuals' social networks influence smoking behaviours; - is there an association between various social and cultural factors and being a smoker or non-smoker; and - does a multi-component tobacco control program impact positively on tobacco behaviours, attitudes and beliefs in Indigenous Australians. Methods and design Our prospective study will use a mixed-method approach (qualitative and quantitative), including a pre- and post-test evaluation of a tobacco control initiative. The study will explore the social and cultural context underlying Indigenous Australian tobacco use and associated factors which influence smoking behaviour. Primary data will be collected via a panel survey, interviews and focus groups. Secondary data will include de-identified PBS items related to smoking and also data collected from the Quitlines call service. Network analysis will be used to assess whether social networks influence smoking behaviours. For the survey, baseline differences will be tested using chi2 statistics for the categorical and dichotomous variables and t-tests for the continuous variables, where appropriate. Grounded theory will be used to analyse the interviews and focus groups. Local Aboriginal community controlled organisations will partner in the study. Discussion Our study will explore the key factors, including the influence of social networks, that impact on tobacco use and the extent to which smoking behaviours transcend networks within the Indigenous Australian community in the ACT. This will add to the evidence-base, identifying influential factors to tobacco use and the effectiveness and influence of a multi-component tobacco control strategy. PMID:24060337

The Telecommunications and Data Acquisition Report

NASA Technical Reports Server (NTRS)

Posner, E. C. (Editor)

1990-01-01

Archival reports on developments in programs managed by the Jet Propulsion Laboratory's (JPL) Office of Telecommunications and Data Acquisition (TDA) are given. Space communications, radio navigation, radio science, and ground-based radio and radar astronomy, activities of the Deep Space Network (DSN) and its associated Ground Communications Facility (GCF) in planning, supporting research and technology, implementation, and operations are reported. Also included is TDA-funded activity at JPL on data and information systems and reimbursable Deep Space Network (DSN) work performed for other space agencies through NASA.

Coupling of ground biosensor networks for water monitoring with satellite observations in assessing Leptospirosis

NASA Astrophysics Data System (ADS)

Skouloudis, A. N.; Rickerby, D. G.

2012-12-01

Leptospirosis became recently a major public-health problem that is closely related with the environment (Nature review Oct 2009, Vol 7, pp 736-747). This disease originates from zoonotic pathogens associated with asymptomatic rodent carriers. Unfortunately, it effects human populations via various direct and indirect routes. This disease can claim many victims with large outbreaks during natural disasters or floods occurring during seasonal conditions. The severity of the illness ranges from subclinical infection to a fulminating fatal disease. Improved water quality monitoring techniques based on biosensor, optical, micro-fluidic and information technologies are leading to radical changes in our ability to perceive and monitor the aquatic environment. Biosensors are capable of providing specific, high spatial resolution information and allow unattended operation that will be particularly useful for water borne related diseases. Current research on biosensors is leading to solutions to problems for several contaminants that were previously irresolvable due to their high degree of complexity. Networking of the sensors enables sensitive monitoring systems allowing real-time monitoring of pollutants and facilitates data transmission between the measurement points and central control stations for continuous surveillance and to provide an early warning capability. The application of intelligent biosensor networks for water quality monitoring and detection of localized sources of pollution are discussed together with the setting up of a methodology that utilizes images from satellite coupled with in-situ sensors for anticipating the zones of potential evolution of this disease and assessing the population at risk. Environmental and climatic conditions that are associated the outbreaks are described and the rational of combining earth observations coupled with advanced in-situ biosensors is explained. The implementation of sensor networks for data collection and exposure mapping is reliant on the identification of location where such networks could be of use. Systematic monitoring from satellite images are utilized for increasing the potential areas of application, for assessing the geographical representativeness on the measurements of the sensors and proposing the methodology on assessing the environmental conditions that are associated with outbreaks of leptospirosis. Unfortunately, several combined deployments of earth observations with ground sensors are required before for the understanding of the connections between hydrology and the human health. Ultimately this will lead to the establishment of early warning system that might investigate the effectiveness of key control measures, including vaccine (when they will become available) and affront the water decontamination, and animal control issues.

Cooperative UAV-Based Communications Backbone for Sensor Networks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roberts, R S

2001-10-07

The objective of this project is to investigate the use of unmanned air vehicles (UAVs) as mobile, adaptive communications backbones for ground-based sensor networks. In this type of network, the UAVs provide communication connectivity to sensors that cannot communicate with each other because of terrain, distance, or other geographical constraints. In these situations, UAVs provide a vertical communication path for the sensors, thereby mitigating geographic obstacles often imposed on networks. With the proper use of UAVs, connectivity to a widely disbursed sensor network in rugged terrain is readily achieved. Our investigation has focused on networks where multiple cooperating UAVs aremore » used to form a network backbone. The advantage of using multiple UAVs to form the network backbone is parallelization of sensor connectivity. Many widely spaced or isolated sensors can be connected to the network at once using this approach. In these networks, the UAVs logically partition the sensor network into sub-networks (subnets), with one UAV assigned per subnet. Partitioning the network into subnets allows the UAVs to service sensors in parallel thereby decreasing the sensor-to-network connectivity. A UAV services sensors in its subnet by flying a route (path) through the subnet, uplinking data collected by the sensors, and forwarding the data to a ground station. An additional advantage of using multiple UAVs in the network is that they provide redundancy in the communications backbone, so that the failure of a single UAV does not necessarily imply the loss of the network.« less

Effect of regional slope on drainage networks

NASA Astrophysics Data System (ADS)

Phillips, Loren F.; Schumm, S. A.

1987-09-01

Drainage networks that develop under conditions of no structural control and homogeneous lithology are generally dendritic, depending upon the shape and inclination of the surface on which they form. An experimental study was designed to investigate the effect of an increase of slope on the evolution and development of dendritic drainage patterns. As slope steepens, the pattern changes from dendritic at 1% slope, to subdendritic at 2%, to subparallel at 3%, to parallel at 5% and higher. The change from a dendritic-type pattern to a parallel-type pattern occurs at a low slope, between 2% and 3%, and primary channel junction angles decrease abruptly from about 60° to 43°. *Present address: U.S. Army Environmental Hygiene Agency, Attn: HSHB-ME-WM, Aberdeen Proving Ground, Maryland 21010-5422

An In Depth Look at Lightning Trends in Hurricane Harvey using Satellite and Ground-Based Measurements

NASA Astrophysics Data System (ADS)

Ringhausen, J.

2017-12-01

This research combines satellite measurements of lightning in Hurricane Harvey with ground-based lightning measurements to get a better sense of the total lightning occurring in the hurricane, both intra-cloud (IC) and cloud-to-ground (CG), and how it relates to the intensification and weakening of the tropical system. Past studies have looked at lightning trends in hurricanes using the space based Lightning Imaging Sensor (LIS) or ground-based lightning detection networks. However, both of these methods have drawbacks. For instance, LIS was in low earth orbit, which limited lightning observations to 90 seconds for a particular point on the ground; hence, continuous lightning coverage of a hurricane was not possible. Ground-based networks can have a decreased detection efficiency, particularly for ICs, over oceans where hurricanes generally intensify. With the launch of the Geostationary Lightning Mapper (GLM) on the GOES-16 satellite, researchers can study total lightning continuously over the lifetime of a tropical cyclone. This study utilizes GLM to investigate total lightning activity in Hurricane Harvey temporally; this is augmented with spatial analysis relative to hurricane structure, similar to previous studies. Further, GLM and ground-based network data are combined using Bayesian techniques in a new manner to leverage the strengths of each detection method. This methodology 1) provides a more complete estimate of lightning activity and 2) enables the derivation of the IC:CG ratio (Z-ratio) throughout the time period of the study. In particular, details of the evolution of the Z-ratio in time and space are presented. In addition, lightning stroke spatiotemporal trends are compared to lightning flash trends. This research represents a new application of lightning data that can be used in future study of tropical cyclone intensification and weakening.

Tensor network state correspondence and holography

NASA Astrophysics Data System (ADS)

Singh, Sukhwinder

2018-01-01

In recent years, tensor network states have emerged as a very useful conceptual and simulation framework to study quantum many-body systems at low energies. In this paper, we describe a particular way in which any given tensor network can be viewed as a representation of two different quantum many-body states. The two quantum many-body states are said to correspond to each other by means of the tensor network. We apply this "tensor network state correspondence"—a correspondence between quantum many-body states mediated by tensor networks as we describe—to the multi-scale entanglement renormalization ansatz (MERA) representation of ground states of one dimensional (1D) quantum many-body systems. Since the MERA is a 2D hyperbolic tensor network (the extra dimension is identified as the length scale of the 1D system), the two quantum many-body states obtained from the MERA, via tensor network state correspondence, are seen to live in the bulk and on the boundary of a discrete hyperbolic geometry. The bulk state so obtained from a MERA exhibits interesting features, some of which caricature known features of the holographic correspondence of String theory. We show how (i) the bulk state admits a description in terms of "holographic screens", (ii) the conformal field theory data associated with a critical ground state can be obtained from the corresponding bulk state, in particular, how pointlike boundary operators are identified with extended bulk operators. (iii) We also present numerical results to illustrate that bulk states, dual to ground states of several critical spin chains, have exponentially decaying correlations, and that the bulk correlation length generally decreases with increase in central charge for these spin chains.

The EDSN Intersatellite Communications Architecture

NASA Technical Reports Server (NTRS)

Hanson, John; Chartres, James; Sanchez, Hugo; Oyadomari, Ken

2014-01-01

The Edison Demonstration of Smallsat Networks (EDSN) is a swarm of eight 1.5U Cubesats developed by the NASA Ames Research Center under the Small Spacecraft Technology Program (SSTP) within NASA Space Technology Mission Directorate (STMD). EDSN, scheduled for launch in late 2014, is designed to explore the use of small spacecraft networks to make synchronized, multipoint scientific measurements, and to organize and pass those data to the ground through their network. Networked swarms of these small spacecraft will open new horizons in astronomy, Earth observations and solar physics. Their range of applications include the formation of synthetic aperture radars for Earth sensing systems, large aperture observatories for next generation telescopes and the collection of spatially distributed measurements of time varying systems, probing the Earth's magnetosphere, Earth-Sun interactions and the Earth's geopotential. The EDSN communications network is maintained and operated by a simple set of predefined rules operating independently on all eight spacecraft without direction from ground based systems. One spacecraft serves as a central node, requesting and collecting data from the other seven spacecraft, organizing the data and passing it to a ground station at regular intervals. The central node is rotated among the spacecraft on a regular basis, providing robustness against the failure of a single spacecraft. This paper describes the communication architecture of the EDSN network and its operation with small spacecraft of limited electrical power, computing power and communication range. Furthermore, the problems of collecting and prioritizing data through a system that has data throughput bottlenecks are addressed. Finally, future network enhancements that can be built on top of the current EDSN hardware are discussed.

Towards Integrated Marmara Strong Motion Network

NASA Astrophysics Data System (ADS)

Durukal, E.; Erdik, M.; Safak, E.; Ansal, A.; Ozel, O.; Alcik, H.; Mert, A.; Kafadar, N.; Korkmaz, A.; Kurtulus, A.

2009-04-01

Istanbul has a 65% chance of having a magnitude 7 or above earthquake within the next 30 years. As part of the preparations for the future earthquake, strong motion networks have been installed in and around Istanbul. The Marmara Strong Motion Network, operated by the Department of Earthquake Engineering of Kandilli Observatory and Earthquake Research Institute, encompasses permanent systems outlined below. It is envisaged that the networks will be run by a single entity responsible for technical management and maintanence, as well as for data management, archiving and dissemination through dedicated web-based interfaces. • Istanbul Earthquake Rapid Response and Early Warning System - IERREWS (one hundred 18-bit accelerometers for rapid response; ten 24-bit accelerometers for early warning) • IGDAŞ Gas Shutoff Network (100 accelerometers to be installed in 2010 and integrated with IERREWS) • Structural Monitoring Arrays - Fatih Sultan Mehmet Suspension Bridge (1200m-long suspension bridge across the Bosphorus, five 3-component accelerometers + GPS sensors) - Hagia Sophia Array (1500-year-old historical edifice, 9 accelerometers) - Süleymaniye Mosque Array (450-year-old historical edifice,9 accelerometers) - Fatih Mosque Array (237-year-old historical edifice, 9 accelerometers) - Kanyon Building Array (high-rise office building, 5 accelerometers) - Isbank Tower Array (high-rise office building, 5 accelerometers) - ENRON Array (power generation facility, 4 acelerometers) - Mihrimah Sultan Mosque Array (450-year-old historical edifice,9 accelerometers + tiltmeters, to be installed in 2009) - Sultanahmet Mosque Array, (390-year-old historical edifice, 9 accelerometers + tiltmeters, to be installed in 2009) • Special Arrays - Atakoy Vertical Array (four 3-component accelerometers at 25, 50, 75, and 150 m depths) - Marmara Tube Tunnel (1400 m long submerged tunnel, 128 ch. accelerometric data, 24 ch. strain data, to be installed in 2010) - Air-Force Academy Array (72 ch. dense accelerometric array to be installed in 2010) - Gemlik Array (a dense basin array of 8 stations, to be installed in 2010) The objectives of these systems and networks are: (1) to produce rapid earthquake intensity, damage and loss assessment information after an earthquake (in the case of IERREWS), (2) to monitor conditions of structural systems, (3) to develop real-time data processing, analysis, and damage detection and location tools (in the case of structural networks) after an extreme event, (4) to assess spatial properties of strong ground motion and ground strain, and to characterise basin response (in the case of special arrays), (5) to investigate site response and wave propagation (in the case of vertical array). Ground motion data obtained from these strong motion networks have and are being used for investigations of attenuation, spatial variation (coherence), simulation benchmarking, source modeling, site response, seismic microzonation, system identification and structural model verification and structural health control. In addition to the systems and networks outlined above there are two temporary networks: KIMNET - a dense urban noise and microtremor network consisting of 50 broadband stations expected to be operational in mid 2009, and SOSEWIN - a 20-station, self-organizing structural integrated array at Ataköy in Istanbul.

Open solutions to distributed control in ground tracking stations

NASA Technical Reports Server (NTRS)

Heuser, William Randy

1994-01-01

The advent of high speed local area networks has made it possible to interconnect small, powerful computers to function together as a single large computer. Today, distributed computer systems are the new paradigm for large scale computing systems. However, the communications provided by the local area network is only one part of the solution. The services and protocols used by the application programs to communicate across the network are as indispensable as the local area network. And the selection of services and protocols that do not match the system requirements will limit the capabilities, performance, and expansion of the system. Proprietary solutions are available but are usually limited to a select set of equipment. However, there are two solutions based on 'open' standards. The question that must be answered is 'which one is the best one for my job?' This paper examines a model for tracking stations and their requirements for interprocessor communications in the next century. The model and requirements are matched with the model and services provided by the five different software architectures and supporting protocol solutions. Several key services are examined in detail to determine which services and protocols most closely match the requirements for the tracking station environment. The study reveals that the protocols are tailored to the problem domains for which they were originally designed. Further, the study reveals that the process control model is the closest match to the tracking station model.

Virtual Mission Operations of Remote Sensors With Rapid Access To and From Space

NASA Technical Reports Server (NTRS)

Ivancic, William D.; Stewart, Dave; Walke, Jon; Dikeman, Larry; Sage, Steven; Miller, Eric; Northam, James; Jackson, Chris; Taylor, John; Lynch, Scott;

47 CFR 27.16 - Network access requirements for Block C in the 746-757 and 776-787 MHz bands.

Code of Federal Regulations, 2013 CFR

2013-10-01

... jeopardizing network security. The potential for excessive bandwidth demand alone shall not constitute grounds... 47 Telecommunication 2 2013-10-01 2013-10-01 false Network access requirements for Block C in the... § 27.16 Network access requirements for Block C in the 746-757 and 776-787 MHz bands. (a) Applicability...

47 CFR 27.16 - Network access requirements for Block C in the 746-757 and 776-787 MHz bands.

Code of Federal Regulations, 2014 CFR

2014-10-01

... jeopardizing network security. The potential for excessive bandwidth demand alone shall not constitute grounds... 47 Telecommunication 2 2014-10-01 2014-10-01 false Network access requirements for Block C in the... § 27.16 Network access requirements for Block C in the 746-757 and 776-787 MHz bands. (a) Applicability...

47 CFR 27.16 - Network access requirements for Block C in the 746-757 and 776-787 MHz bands.

Code of Federal Regulations, 2012 CFR

2012-10-01

... jeopardizing network security. The potential for excessive bandwidth demand alone shall not constitute grounds... 47 Telecommunication 2 2012-10-01 2012-10-01 false Network access requirements for Block C in the... § 27.16 Network access requirements for Block C in the 746-757 and 776-787 MHz bands. (a) Applicability...

In-Space Crew-Collaborative Task Scheduling

NASA Technical Reports Server (NTRS)

Jaap, John; Meyer, Patrick; Davis, Elizabeth; Richardson, Lea

2006-01-01

As humans venture farther from Earth for longer durations, it will become essential for those on the journey to have significant control over the scheduling of their own activities as well as the activities of their companion systems and robots. However, the crew will not do all the scheduling; timelines will be the result of collaboration with ground personnel. Emerging technologies such as in-space message buses, delay-tolerant networks, and in-space internet will be the carriers on which the collaboration rides. Advances in scheduling technology, in the areas of task modeling, scheduling engines, and user interfaces will allow the crew to become virtual scheduling experts. New concepts of operations for producing the timeline will allow the crew and the ground support to collaborate while providing safeguards to ensure that the mission will be effectively accomplished without endangering the systems or personnel.

Linear Power-Flow Models in Multiphase Distribution Networks: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bernstein, Andrey; Dall'Anese, Emiliano

This paper considers multiphase unbalanced distribution systems and develops approximate power-flow models where bus-voltages, line-currents, and powers at the point of common coupling are linearly related to the nodal net power injections. The linearization approach is grounded on a fixed-point interpretation of the AC power-flow equations, and it is applicable to distribution systems featuring (i) wye connections; (ii) ungrounded delta connections; (iii) a combination of wye-connected and delta-connected sources/loads; and, (iv) a combination of line-to-line and line-to-grounded-neutral devices at the secondary of distribution transformers. The proposed linear models can facilitate the development of computationally-affordable optimization and control applications -- frommore » advanced distribution management systems settings to online and distributed optimization routines. Performance of the proposed models is evaluated on different test feeders.« less

Grounding Action Words in the Sensorimotor Interaction with the World: Experiments with a Simulated iCub Humanoid Robot

PubMed Central

Marocco, Davide; Cangelosi, Angelo; Fischer, Kerstin; Belpaeme, Tony

2010-01-01

This paper presents a cognitive robotics model for the study of the embodied representation of action words. The present research will present how an iCub humanoid robot can learn the meaning of action words (i.e. words that represent dynamical events that happen in time) by physically interacting with the environment and linking the effects of its own actions with the behavior observed on the objects before and after the action. The control system of the robot is an artificial neural network trained to manipulate an object through a Back-Propagation-Through-Time algorithm. We will show that in the presented model the grounding of action words relies directly to the way in which an agent interacts with the environment and manipulates it. PMID:20725503

Use of the Delay-Tolerant Networking Bundle Protocol from Space

NASA Technical Reports Server (NTRS)

Wood, Lloyd; Ivancic, William D.; Eddy, Wesley M.; Stewart, Dave; Northam, James; Jackson, Chris; daSilvaCuriel, Alex

2009-01-01

The Disaster Monitoring Constellation (DMC), constructed by Survey Satellite Technology Ltd (SSTL), is a multisatellite Earth-imaging low-Earth-orbit sensor network where captured image swaths are stored onboard each satellite and later downloaded from the satellite payloads to a ground station. Store-and-forward of images with capture and later download gives each satellite the characteristics of a node in a Delay/Disruption Tolerant Network (DTN). Originally developed for the Interplanetary Internet, DTNs are now under investigation in an Internet Research Task Force (IRTF) DTN research group (RG), which has developed a bundle architecture and protocol. The DMC is currently unique in its adoption of the Internet Protocol (IP) for its imaging payloads and for satellite command and control, based around reuse of commercial networking and link protocols. These satellites use of IP has enabled earlier experiments with the Cisco router in Low Earth Orbit (CLEO) onboard the constellation's UK-DMC satellite. Earth images are downloaded from the satellites using a custom IPbased high-speed transfer protocol developed by SSTL, Saratoga, which tolerates unusual link environments. Saratoga has been documented in the Internet Engineering Task Force (IETF) for wider adoption. We experiment with use of DTNRG bundle concepts onboard the UKDMC satellite, by examining how Saratoga can be used as a DTN convergence layer to carry the DTNRG Bundle Protocol, so that sensor images can be delivered to ground stations and beyond as bundles. This is the first successful use of the DTNRG Bundle Protocol in a space environment. We use our practical experience to examine the strengths and weaknesses of the Bundle Protocol for DTN use, paying attention to fragmentation, custody transfer, and reliability issues.

On-board closed-loop congestion control for satellite based packet switching networks

NASA Technical Reports Server (NTRS)

Chu, Pong P.; Ivancic, William D.; Kim, Heechul

1993-01-01

NASA LeRC is currently investigating a satellite architecture that incorporates on-board packet switching capability. Because of the statistical nature of packet switching, arrival traffic may fluctuate and thus it is necessary to integrate congestion control mechanism as part of the on-board processing unit. This study focuses on the closed-loop reactive control. We investigate the impact of the long propagation delay on the performance and propose a scheme to overcome the problem. The scheme uses a global feedback signal to regulate the packet arrival rate of ground stations. In this scheme, the satellite continuously broadcasts the status of its output buffer and the ground stations respond by selectively discarding packets or by tagging the excessive packets as low-priority. The two schemes are evaluated by theoretical queuing analysis and simulation. The former is used to analyze the simplified model and to determine the basic trends and bounds, and the later is used to assess the performance of a more realistic system and to evaluate the effectiveness of more sophisticated control schemes. The results show that the long propagation delay makes the closed-loop congestion control less responsive. The broadcasted information can only be used to extract statistical information. The discarding scheme needs carefully-chosen status information and reduction function, and normally requires a significant amount of ground discarding to reduce the on-board packet loss probability. The tagging scheme is more effective since it tolerates more uncertainties and allows a larger margin of error in status information. It can protect the high-priority packets from excessive loss and fully utilize the downlink bandwidth at the same time.

Data fusion for target tracking and classification with wireless sensor network

NASA Astrophysics Data System (ADS)

Pannetier, Benjamin; Doumerc, Robin; Moras, Julien; Dezert, Jean; Canevet, Loic

2016-10-01

In this paper, we address the problem of multiple ground target tracking and classification with information obtained from a unattended wireless sensor network. A multiple target tracking (MTT) algorithm, taking into account road and vegetation information, is proposed based on a centralized architecture. One of the key issue is how to adapt classical MTT approach to satisfy embedded processing. Based on track statistics, the classification algorithm uses estimated location, velocity and acceleration to help to classify targets. The algorithms enables tracking human and vehicles driving both on and off road. We integrate road or trail width and vegetation cover, as constraints in target motion models to improve performance of tracking under constraint with classification fusion. Our algorithm also presents different dynamic models, to palliate the maneuvers of targets. The tracking and classification algorithms are integrated into an operational platform (the fusion node). In order to handle realistic ground target tracking scenarios, we use an autonomous smart computer deposited in the surveillance area. After the calibration step of the heterogeneous sensor network, our system is able to handle real data from a wireless ground sensor network. The performance of system is evaluated in a real exercise for intelligence operation ("hunter hunt" scenario).

Track classification within wireless sensor network

NASA Astrophysics Data System (ADS)

Doumerc, Robin; Pannetier, Benjamin; Moras, Julien; Dezert, Jean; Canevet, Loic

2017-05-01

In this paper, we present our study on track classification by taking into account environmental information and target estimated states. The tracker uses several motion model adapted to different target dynamics (pedestrian, ground vehicle and SUAV, i.e. small unmanned aerial vehicle) and works in centralized architecture. The main idea is to explore both: classification given by heterogeneous sensors and classification obtained with our fusion module. The fusion module, presented in his paper, provides a class on each track according to track location, velocity and associated uncertainty. To model the likelihood on each class, a fuzzy approach is used considering constraints on target capability to move in the environment. Then the evidential reasoning approach based on Dempster-Shafer Theory (DST) is used to perform a time integration of this classifier output. The fusion rules are tested and compared on real data obtained with our wireless sensor network.In order to handle realistic ground target tracking scenarios, we use an autonomous smart computer deposited in the surveillance area. After the calibration step of the heterogeneous sensor network, our system is able to handle real data from a wireless ground sensor network. The performance of this system is evaluated in a real exercise for intelligence operation ("hunter hunt" scenario).

Aerosol Remote Sensing from AERONET, the Ground-Based Satellite

NASA Technical Reports Server (NTRS)

Holben, Brent N.

2012-01-01

Atmospheric particles including mineral dust, biomass burning smoke, pollution from carbonaceous aerosols and sulfates, sea salt, impact air quality and climate. The Aerosol Robotic Network (AERONET) program, established in the early 1990s, is a federation of ground-based remote sensing aerosol networks of Sun/sky radiometers distributed around the world, which provides a long-term, continuous and readily accessible public domain database of aerosol optical (e.g., aerosol optical depth) and microphysical (e.g., aerosol volume size distribution) properties for aerosol characterization, validation of satellite retrievals, and synergism with Earth science databases. Climatological aerosol properties will be presented at key worldwide locations exhibiting discrete dominant aerosol types. Further, AERONET's temporary mesoscale network campaign (e.g., UAE2, TIGERZ, DRAGON-USA.) results that attempt to quantify spatial and temporal variability of aerosol properties, establish validation of ground-based aerosol retrievals using aircraft profile measurements, and measure aerosol properties on compatible spatial scales with satellite retrievals and aerosol transport models allowing for more robust validation will be discussed.

Cross-Referencing GLM and ISS-LIS with Ground-Based Lightning Networks

NASA Astrophysics Data System (ADS)

Virts, K.; Blakeslee, R. J.; Goodman, S. J.; Koshak, W. J.

2017-12-01

The Geostationary Lightning Mapper (GLM), in geostationary orbit aboard GOES-16 since late 2016, and the Lightning Imaging Sensor (LIS), installed on the International Space Station in February 2017, provide observations of total lightning activity from space. ISS-LIS samples the global tropics and mid-latitudes, while GLM observes the full thunderstorm life-cycle over the Americas and surrounding oceans. The launch of these instruments provides an unprecedented opportunity to compare lightning observations across multiple space-based optical lightning sensors. In this study, months of observations from GLM and ISS-LIS are cross-referenced with each other and with lightning detected by the ground-based Earth Networks Global Lightning Network (ENGLN) and the Vaisala Global Lightning Dataset 360 (GLD360) throughout and beyond the GLM field-of-view. In addition to calibration/validation of the new satellite sensors, this study provides a statistical comparison of the characteristics of lightning observed by the satellite and ground-based instruments, with an emphasis on the lightning flashes uniquely identified by the satellites.

Bifurcation analysis of eight coupled degenerate optical parametric oscillators

NASA Astrophysics Data System (ADS)

Ito, Daisuke; Ueta, Tetsushi; Aihara, Kazuyuki

2018-06-01

A degenerate optical parametric oscillator (DOPO) network realized as a coherent Ising machine can be used to solve combinatorial optimization problems. Both theoretical and experimental investigations into the performance of DOPO networks have been presented previously. However a problem remains, namely that the dynamics of the DOPO network itself can lower the search success rates of globally optimal solutions for Ising problems. This paper shows that the problem is caused by pitchfork bifurcations due to the symmetry structure of coupled DOPOs. Some two-parameter bifurcation diagrams of equilibrium points express the performance deterioration. It is shown that the emergence of non-ground states regarding local minima hampers the system from reaching the ground states corresponding to the global minimum. We then describe a parametric strategy for leading a system to the ground state by actively utilizing the bifurcation phenomena. By adjusting the parameters to break particular symmetry, we find appropriate parameter sets that allow the coherent Ising machine to obtain the globally optimal solution alone.

The Wireless Data Acquisition System for the Vibration Table

NASA Astrophysics Data System (ADS)

Teng, Y. T.; Hu, X.

2014-12-01

The vibration table is a large-scaled tool used for inspecting the performance of seismometers. The output from a seismometer on the table can be directly monitored when the vibration table moves in certain pattern. Compared with other inspection methods, inspecting seismometers' performance indicators (frequency response, degree of linearity, sensitivity, lateral inhibition and dynamic range etc). using vibration tables is more intuitive. Therefore, the vibration tables are an essential testing part in developing new seismometers and seismometer quality control. Whereas, in practice, a cable is needed to connect the seismometer to the ground equipments for its signal outputs and power supply, that means adding a time-varying nonlinear spring between the vibration table and ground. The cable adds nonlinear feature to the table, distorts the table-board movement and bring extra errors to the inspecting work and affected the testing accuracy and precision. In face of this problem, we developed a wireless acquiring system for the vibration table. The system is consisted of a three-channel analog-to-digital conversion, an acquisition control part, local data storage, network interface, wireless router and power management, etc. The analog-to-digital conversion part uses a 24-digit high-precision converter, which has a programmable amplifier at the front end of its artificial circuit, with the function of matching outputs with different amplifier from the vibration table. The acquisition control part uses a 32 bit ARM processor, with low-power dissipation, minute extension and high performance. The application software platform is written in Linux to make the system convenient for multitasking work. Large volume local digital storage is achieved by a 32G SD card, which is used for saving real time acquired data. Data transmission is achieved by network interface and wireless router, which can simplify the application software by the supported TCP/IP protocol. Besides, the acquisition system uses built-in power supply, which provides power to the system with Li-On rechargeable battery with high capacity, then all the cable link between the vibration table and the ground equipment have been removed. With all these changes, the whole system is immobilized on board of the vibration table after being packaged.

A new control system hardware architecture for the Hobby-Eberly Telescope prime focus instrument package

NASA Astrophysics Data System (ADS)

Ramiller, Chuck; Taylor, Trey; Rafferty, Tom H.; Cornell, Mark E.; Rafal, Marc; Savage, Richard

2010-07-01

The Hobby-Eberly Telescope (HET) will be undergoing a major upgrade as a precursor to the HET Dark Energy Experiment (HETDEX‡). As part of this upgrade, the Prime Focus Instrument Package (PFIP) will be replaced with a new design that supports the HETDEX requirements along with the existing suite of instruments and anticipated future additions. This paper describes the new PFIP control system hardware plus the physical constraints and other considerations driving its design. Because of its location at the top end of the telescope, the new PFIP is essentially a stand-alone remote automation island containing over a dozen subsystems. Within the PFIP, motion controllers and modular IO systems are interconnected using a local Controller Area Network (CAN) bus and the CANOpen messaging protocol. CCD cameras that are equipped only with USB 2.0 interfaces are connected to a local Ethernet network via small microcontroller boards running embedded Linux. Links to ground-level systems pass through a 100 m cable bundle and use Ethernet over fiber optic cable exclusively; communications are either direct or through Ethernet/CAN gateways that pass CANOpen messages transparently. All of the control system hardware components are commercially available, designed for rugged industrial applications, and rated for extended temperature operation down to -10 °C.

Detecting volcanic sulfur dioxide plumes in the Northern Hemisphere using the Brewer spectrophotometers, other networks, and satellite observations

NASA Astrophysics Data System (ADS)

Zerefos, Christos S.; Eleftheratos, Kostas; Kapsomenakis, John; Solomos, Stavros; Inness, Antje; Balis, Dimitris; Redondas, Alberto; Eskes, Henk; Allaart, Marc; Amiridis, Vassilis; Dahlback, Arne; De Bock, Veerle; Diémoz, Henri; Engelmann, Ronny; Eriksen, Paul; Fioletov, Vitali; Gröbner, Julian; Heikkilä, Anu; Petropavlovskikh, Irina; Jarosławski, Janusz; Josefsson, Weine; Karppinen, Tomi; Köhler, Ulf; Meleti, Charoula; Repapis, Christos; Rimmer, John; Savinykh, Vladimir; Shirotov, Vadim; Siani, Anna Maria; Smedley, Andrew R. D.; Stanek, Martin; Stübi, René

2017-01-01

This study examines the adequacy of the existing Brewer network to supplement other networks from the ground and space to detect SO2 plumes of volcanic origin. It was found that large volcanic eruptions of the last decade in the Northern Hemisphere have a positive columnar SO2 signal seen by the Brewer instruments located under the plume. It is shown that a few days after the eruption the Brewer instrument is capable of detecting significant columnar SO2 increases, exceeding on average 2 DU relative to an unperturbed pre-volcanic 10-day baseline, with a mean close to 0 and σ = 0.46, as calculated from the 32 Brewer stations under study. Intercomparisons with independent measurements from the ground and space as well as theoretical calculations corroborate the capability of the Brewer network to detect volcanic plumes. For instance, the comparison with OMI (Ozone Monitoring Instrument) and GOME-2 (Global Ozone Monitoring Experiment-2) SO2 space-borne retrievals shows statistically significant agreement between the Brewer network data and the collocated satellite overpasses in the case of the Kasatochi eruption. Unfortunately, due to sparsity of satellite data, the significant positive departures seen in the Brewer and other ground networks following the Eyjafjallajökull, Bárðarbunga and Nabro eruptions could not be statistically confirmed by the data from satellite overpasses. A model exercise from the MACC (Monitoring Atmospheric Composition and Climate) project shows that the large increases in SO2 over Europe following the Bárðarbunga eruption in Iceland were not caused by local pollution sources or ship emissions but were clearly linked to the volcanic eruption. Sulfur dioxide positive departures in Europe following Bárðarbunga could be traced by other networks from the free troposphere down to the surface (AirBase (European air quality database) and EARLINET (European Aerosol Research Lidar Network)). We propose that by combining Brewer data with that from other networks and satellites, a useful tool aided by trajectory analyses and modelling could be created which can also be used to forecast high SO2 values both at ground level and in air flight corridors following future eruptions.

Using a Network of Boundary Layer Profilers to Characterize the Atmosphere at a Major Spaceport

NASA Technical Reports Server (NTRS)

Case, Jonathan L.; Lambert, Winifred; Merceret, Francis; Ward, Jennifer

2006-01-01

Space launch, landing, and ground operations at the Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS) in east-central Florida are highly sensitive to mesoscale weather conditions throughout the year. Due to the complex land-water interfaces and the important role of mesoscale circulations, a high-resolution network of five 915-MHz Doppler Radar Wind Profilers (DRWP) and 44 wind towers was installed over the KSC/CCAFS area. By using quality-controlled 915-MHz DRAT data along with the near-surface tower observations, the Applied Meteorology Unit and KSC Weather Office have studied the development and evolution of various mesoscale phenomena across KSC/CCAFS such as sea and land breezes, low-level jets, and frontal passages. This paper will present some examples of mesoscale phenomena that can impact space operations at KSC/CCAFS, focusing on the utility of the 915-MHz DRWP network in identifying important characteristics of sea/land breezes and low-level jets.

Groundwater sapping valleys: Experimental studies, geological controls and implications to the interpretation of valley networks on Mars

NASA Technical Reports Server (NTRS)

Kochel, R. Craig

1988-01-01

An integrated approach using experimental laboratory models, field studies of terrestrial analogs, and remote studies of terrestrial field sites were applied to the goals of understanding the nature and morphology of valley networks formed by groundwater sapping. In spite of problems with scaling, the experimental studies provide valuable insights into concepts relating to the initiation, development, and evolution of valleys by groundwater sapping. These investigations are also aimed at developing geomorphic criteria for distinguishing valleys formed by surface runoff from those formed by groundwater sapping processes. Channels that were field classified as sapping vs. runoff were successfully distinguished using statistical analysis of their respective morphologies; therefore, it may be possible to use similar techniques to interpret channel genesis on Mars. The terrestrial and flume studies provide the ground truth dataset which can be used (and will be during the present year) to help interpret the genesis of valley networks on Mars.

Microprocessor control and networking for the amps breadboard

NASA Technical Reports Server (NTRS)

Floyd, Stephen A.

1987-01-01

Future space missions will require more sophisticated power systems, implying higher costs and more extensive crew and ground support involvement. To decrease this human involvement, as well as to protect and most efficiently utilize this important resource, NASA has undertaken major efforts to promote progress in the design and development of autonomously managed power systems. Two areas being actively pursued are autonomous power system (APS) breadboards and knowledge-based expert system (KBES) applications. The former are viewed as a requirement for the timely development of the latter. Not only will they serve as final testbeds for the various KBES applications, but will play a major role in the knowledge engineering phase of their development. The current power system breadboard designs are of a distributed microprocessor nature. The distributed nature, plus the need to connect various external computer capabilities (i.e., conventional host computers and symbolic processors), places major emphasis on effective networking. The communications and networking technologies for the first power system breadboard/test facility are described.

A neurocomputational model of figure-ground discrimination and target tracking.

PubMed

Sun, H; Liu, L; Guo, A

1999-01-01

A neurocomputational model is presented for figureground discrimination and target tracking. In the model, the elementary motion detectors of the correlation type, the computational modules of saccadic and smooth pursuit eye movement, an oscillatory neural-network motion perception module and a selective attention module are involved. It is shown that through the oscillatory amplitude and frequency encoding, and selective synchronization of phase oscillators, the figure and the ground can be successfully discriminated from each other. The receptive fields developed by hidden units of the networks were surprisingly similar to the actual receptive fields and columnar organization found in the primate visual cortex. It is suggested that equivalent mechanisms may exist in the primate visual cortex to discriminate figure-ground in both temporal and spatial domains.

Low-Cost Ground Sensor Network for Intrusion Detection

DTIC Science & Technology

2017-09-01

NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS Approved for public release. Distribution is unlimited. LOW- COST GROUND...Gurminder Singh THIS PAGE INTENTIONALLY LEFT BLANK i REPORT DOCUMENTATION PAGE Form Approved OMB No. 0704-0188 Public reporting burden for this...

Application and API for Real-time Visualization of Ground-motions and Tsunami

NASA Astrophysics Data System (ADS)

Aoi, S.; Kunugi, T.; Suzuki, W.; Kubo, T.; Nakamura, H.; Azuma, H.; Fujiwara, H.

2015-12-01

Due to the recent progress of seismograph and communication environment, real-time and continuous ground-motion observation becomes technically and economically feasible. K-NET and KiK-net, which are nationwide strong motion networks operated by NIED, cover all Japan by about 1750 stations in total. More than half of the stations transmit the ground-motion indexes and/or waveform data in every second. Traditionally, strong-motion data were recorded by event-triggering based instruments with non-continues telephone line which is connected only after an earthquake. Though the data from such networks mainly contribute to preparations for future earthquakes, huge amount of real-time data from dense network are expected to directly contribute to the mitigation of ongoing earthquake disasters through, e.g., automatic shutdown plants and helping decision-making for initial response. By generating the distribution map of these indexes and uploading them to the website, we implemented the real-time ground motion monitoring system, Kyoshin (strong-motion in Japanese) monitor. This web service (www.kyoshin.bosai.go.jp) started in 2008 and anyone can grasp the current ground motions of Japan. Though this service provides only ground-motion map in GIF format, to take full advantage of real-time strong-motion data to mitigate the ongoing disasters, digital data are important. We have developed a WebAPI to provide real-time data and related information such as ground motions (5 km-mesh) and arrival times estimated from EEW (earthquake early warning). All response data from this WebAPI are in JSON format and are easy to parse. We also developed Kyoshin monitor application for smartphone, 'Kmoni view' using the API. In this application, ground motions estimated from EEW are overlapped on the map with the observed one-second-interval indexes. The application can playback previous earthquakes for demonstration or disaster drill. In mobile environment, data traffic and battery are limited and it is not practical to regularly visualize all the data. The application has automatic starting (pop-up) function triggered by EEW. Similar WebAPI and application for tsunami are being prepared using the pressure data recorded by dense offshore observation network (S-net), which is under construction along the Japan Trench.

Questa Baseline and Premining Ground-Water Quality Investigation 18. Characterization of Brittle Structures in the Questa Caldera and Their Potential Influence on Bedrock Ground-Water Flow, Red River Valley, New Mexico

USGS Publications Warehouse

Caine, Jonathan S.

2006-01-01

This report presents a field-based characterization of fractured and faulted crystalline bedrock in the southern portion of the Questa caldera and its margin. The focus is (1) the identification and description of brittle geological structures and (2) speculation on the potential effects and controls that these structures might have on the potential fluxes of paleo to present-day ground water in relation to natural or mining-related metal and acid loads to surface and ground water. The entire study area is pervasively jointed with a few distinctive patterns such as orthogonal, oblique orthogonal, and conjugate joint sets. Joint intensity, the number of joints measured per unit line length, is high to extreme. Three types of fault zones are present that include partially silicified, low- and high-angle faults with well-developed damage zones and clay-rich cores and high-angle, unsilicified open faults. Conceptually, the joint networks can be thought of as providing the background porosity and permeability structure of the bedrock aquifer system. This background is cut by discrete entities such as the faults with clay-rich cores and open faults that may act as important hydrologic heterogeneities. The southern caldera margin runs parallel to the course of the Red River Valley, whose incision has left an extreme topographic gradient at high angles to the river. Many of the faults and fault intersections run parallel to this assumed hydraulic gradient; thus, these structures have great potential to provide paleo and present-day, discrete and anisotropic pathways for solute transport within the otherwise relatively low porosity and permeability bedrock background aquifer system. Although brittle fracture networks and faults are pervasive and complex, simple Darcy calculations are used to estimate the hydraulic conductivity and potential ground-water discharges of the bedrock aquifer, caldera margin, and other faults in order to gain insight into the potential contributions of these features to the ground-water and surface-water flow systems. These calculations show that, because all of these features are found along the Red River in the Cabin Springs-Columbine Park-Goat Hill fan area, their combined effect increases the probability that the bedrock aquifer ground-water flow system provides discharge to the Red River along this reach.

Autonomous Mission Operations for Sensor Webs

NASA Astrophysics Data System (ADS)

Underbrink, A.; Witt, K.; Stanley, J.; Mandl, D.

2008-12-01

We present interim results of a 2005 ROSES AIST project entitled, "Using Intelligent Agents to Form a Sensor Web for Autonomous Mission Operations", or SWAMO. The goal of the SWAMO project is to shift the control of spacecraft missions from a ground-based, centrally controlled architecture to a collaborative, distributed set of intelligent agents. The network of intelligent agents intends to reduce management requirements by utilizing model-based system prediction and autonomic model/agent collaboration. SWAMO agents are distributed throughout the Sensor Web environment, which may include multiple spacecraft, aircraft, ground systems, and ocean systems, as well as manned operations centers. The agents monitor and manage sensor platforms, Earth sensing systems, and Earth sensing models and processes. The SWAMO agents form a Sensor Web of agents via peer-to-peer coordination. Some of the intelligent agents are mobile and able to traverse between on-orbit and ground-based systems. Other agents in the network are responsible for encapsulating system models to perform prediction of future behavior of the modeled subsystems and components to which they are assigned. The software agents use semantic web technologies to enable improved information sharing among the operational entities of the Sensor Web. The semantics include ontological conceptualizations of the Sensor Web environment, plus conceptualizations of the SWAMO agents themselves. By conceptualizations of the agents, we mean knowledge of their state, operational capabilities, current operational capacities, Web Service search and discovery results, agent collaboration rules, etc. The need for ontological conceptualizations over the agents is to enable autonomous and autonomic operations of the Sensor Web. The SWAMO ontology enables automated decision making and responses to the dynamic Sensor Web environment and to end user science requests. The current ontology is compatible with Open Geospatial Consortium (OGC) Sensor Web Enablement (SWE) Sensor Model Language (SensorML) concepts and structures. The agents are currently deployed on the U.S. Naval Academy MidSTAR-1 satellite and are actively managing the power subsystem on-orbit without the need for human intervention.

Design of a monitor and simulation terminal (master) for space station telerobotics and telescience

NASA Technical Reports Server (NTRS)

Lopez, L.; Konkel, C.; Harmon, P.; King, S.

1989-01-01

Based on Space Station and planetary spacecraft communication time delays and bandwidth limitations, it will be necessary to develop an intelligent, general purpose ground monitor terminal capable of sophisticated data display and control of on-orbit facilities and remote spacecraft. The basic elements that make up a Monitor and Simulation Terminal (MASTER) include computer overlay video, data compression, forward simulation, mission resource optimization and high level robotic control. Hardware and software elements of a MASTER are being assembled for testbed use. Applications of Neural Networks (NNs) to some key functions of a MASTER are also discussed. These functions are overlay graphics adjustment, object correlation and kinematic-dynamic characterization of the manipulator.

Station to instrumented aircraft L-band telemetry system and RF signal controller for spacecraft simulations and station calibration

NASA Technical Reports Server (NTRS)

Scaffidi, C. A.; Stocklin, F. J.; Feldman, M. B.

1971-01-01

An L-band telemetry system designed to provide the capability of near-real-time processing of calibration data is described. The system also provides the capability of performing computerized spacecraft simulations, with the aircraft as a data source, and evaluating the network response. The salient characteristics of a telemetry analysis and simulation program (TASP) are discussed, together with the results of TASP testing. The results of the L-band system testing have successfully demonstrated the capability of near-real-time processing of telemetry test data, the control of the ground-received signal to within + or - 0.5 db, and the computer generation of test signals.

Coarse-Grain Bandwidth Estimation Techniques for Large-Scale Space Network

NASA Technical Reports Server (NTRS)

Cheung, Kar-Ming; Jennings, Esther

2013-01-01

In this paper, we describe a top-down analysis and simulation approach to size the bandwidths of a store-andforward network for a given network topology, a mission traffic scenario, and a set of data types with different latency requirements. We use these techniques to estimate the wide area network (WAN) bandwidths of the ground links for different architecture options of the proposed Integrated Space Communication and Navigation (SCaN) Network.

Twenty Years of Litter and Root Manipulations: Insights into Multi-Decadal SOM Dynamics and Controls

NASA Astrophysics Data System (ADS)

Wig, J.; Lajtha, K.; Nadelhoffer, K. J.

2012-12-01

Reforestation, reducing deforestation, and sustainable forest management are often recommended by policy makers to mitigate the greenhouse gas contributions of the forestry sector. However, underlying many of these policy recommendations is the assumption that increasing above-ground carbon stocks corresponds to long-term increases in ecosystem carbon stocks, the majority of which is stored in soils. We analyzed soil carbon and nitrogen dynamics in forest soils that had undergone twenty years of continuous manipulations of above- and below-ground organic inputs as part of the Detritus Input and Removal Treatment (DIRT) network. Although we expected that increased C inputs would correspond to significantly elevated C in surface mineral soils, our data suggest that increasing above-ground litter inputs has had a positive priming effect in this soil. Positive priming occurs when increased rates of litter addition to soil lead to disproportionate increases in microbial respiration rates of native soil C, resulting in a net decrease of soil C. Soil respiration rates in a year-long laboratory incubation support this theory: increased above-ground litter inputs led to decreased respiration rates, suggesting a relative deficit of labile organic matter. Removal of below ground inputs, either with or without above-ground litter inputs, also led to decreased respiration in laboratory incubations, demonstrating the importance of fresh root inputs to labile C. Trends in non-hydrolyzable C fractions, a proxy for the more stable C pool, agree with our respiration measurements. Data from sequential density fractionation are consistent with the hypotheses that priming has occurred in response to increased above-ground litter inputs and that root inputs are an important control of the labile C pool. The importance of roots inputs for C stabilization is well documented in the literature, and our hypothesis that increased above-ground litter inputs leads to priming is supported by data from several other DIRT sites. These data indicate there is an important potential loss of ecosystem C due to priming which should be considered when changing organic inputs to the soil, as is the case in some sustainable forestry recommendations.

Estimation of erosion and sedimentation yield in the Ucayali river basin, a Peruvian tributary of the Amazon River, using ground and satellite methods

NASA Astrophysics Data System (ADS)

Santini, William; Martinez, Jean-Michel; Guyot, Jean-Loup; Espinoza, Raul; Vauchel, Philippe; Lavado, Waldo

2014-05-01

Since 2003, the works of HYBAM observatory (www.ore-hybam.org) has allowed to quantify with accuracy, precision and over a long period Amazon's main rivers discharges and sediments loads. In Peru, a network of 8 stations is regularly gauged and managed in association with the national meteorological and Hydrological service (SENAMHI), the UNALM (National Agrological University of La Molina) and the National Water Agency (ANA). Nevertheless, some current processes of erosion and sedimentation in the foreland basins are still little known, both in volumes and in localization. The sedimentary contributions of Andean tributaries could be there considerable, masking a very strong sedimentation in subsidence zones localized between the control points of the HYBAM's network. The development of spatial techniques such as the Altimetry and reflectance measurement allows us today to complete the ground's network: HYBAM's works have allowed establishing a relation between surface concentration and reflectance in Amazonian rivers (Martinez et al., 2009, Espinoza et al., 2012) and reconstituting water levels series (Calmant et al., 2006, 2008). If the difficulty of calibration of these techniques increases towards the upstream, their use can allow a first characterization of the tributaries contributions and sedimentation zones. At world level, erosion and sedimentation yields in the upper Ucayali are exceptional, favored by a marked seasonality in this region (Espinoza et al., 2009, Lavado, 2010, Pépin et al., 2010) and the presence of cells of extreme precipitation ("Hotspots") (Johnson et al., 1976, Espinoza et al, 2009a). The upper Ucayali drainage basin is a Piggyback where the River run with a low slope, parallel to the Andean range, deposing by gravity hundred millions a year of sands, silts and clays. In this work, we thus propose an estimation of sedimentation and erosion yield in the Ucayali river basin using ground and satellite methods.

Flight Hardware Fabricated for Combustion Science in Space

NASA Technical Reports Server (NTRS)

OMalley, Terence F.; Weiland, Karen J.

2005-01-01

NASA Glenn Research Center s Telescience Support Center (TSC) allows researchers on Earth to operate experiments onboard the International Space Station (ISS) and the space shuttles. NASA s continuing investment in the required software, systems, and networks provides distributed ISS ground operations that enable payload developers and scientists to monitor and control their experiments from the Glenn TSC. The quality of scientific and engineering data is enhanced while the long-term operational costs of experiments are reduced because principal investigators and engineering teams can operate their payloads from their home institutions.

Telesat Canada's mobile satellite system

NASA Astrophysics Data System (ADS)

Bertenyi, E.; Wachira, M.

1987-10-01

Telesat Canada plans to begin instituting mobile satellite ('Msat') services in the early 1990s, in order to permit voice and data communications between land vehicles, aircraft, and ships throughout the remote northern regions and the 200-mile offshore regions of Canada and any other point on Canadian territory. An account is presently given of Msat's overall configuration and projected capacity, together with the design features and performance capabilities of the constituent ground, space, and network control segments. Key technology items are the spacecraft high power RF amplifier and its large deployable antenna.

Satellite-Relayed Intercontinental Quantum Network.

PubMed

Liao, Sheng-Kai; Cai, Wen-Qi; Handsteiner, Johannes; Liu, Bo; Yin, Juan; Zhang, Liang; Rauch, Dominik; Fink, Matthias; Ren, Ji-Gang; Liu, Wei-Yue; Li, Yang; Shen, Qi; Cao, Yuan; Li, Feng-Zhi; Wang, Jian-Feng; Huang, Yong-Mei; Deng, Lei; Xi, Tao; Ma, Lu; Hu, Tai; Li, Li; Liu, Nai-Le; Koidl, Franz; Wang, Peiyuan; Chen, Yu-Ao; Wang, Xiang-Bin; Steindorfer, Michael; Kirchner, Georg; Lu, Chao-Yang; Shu, Rong; Ursin, Rupert; Scheidl, Thomas; Peng, Cheng-Zhi; Wang, Jian-Yu; Zeilinger, Anton; Pan, Jian-Wei

2018-01-19

We perform decoy-state quantum key distribution between a low-Earth-orbit satellite and multiple ground stations located in Xinglong, Nanshan, and Graz, which establish satellite-to-ground secure keys with ∼kHz rate per passage of the satellite Micius over a ground station. The satellite thus establishes a secure key between itself and, say, Xinglong, and another key between itself and, say, Graz. Then, upon request from the ground command, Micius acts as a trusted relay. It performs bitwise exclusive or operations between the two keys and relays the result to one of the ground stations. That way, a secret key is created between China and Europe at locations separated by 7600 km on Earth. These keys are then used for intercontinental quantum-secured communication. This was, on the one hand, the transmission of images in a one-time pad configuration from China to Austria as well as from Austria to China. Also, a video conference was performed between the Austrian Academy of Sciences and the Chinese Academy of Sciences, which also included a 280 km optical ground connection between Xinglong and Beijing. Our work clearly confirms the Micius satellite as a robust platform for quantum key distribution with different ground stations on Earth, and points towards an efficient solution for an ultralong-distance global quantum network.

Satellite-Relayed Intercontinental Quantum Network

NASA Astrophysics Data System (ADS)

Liao, Sheng-Kai; Cai, Wen-Qi; Handsteiner, Johannes; Liu, Bo; Yin, Juan; Zhang, Liang; Rauch, Dominik; Fink, Matthias; Ren, Ji-Gang; Liu, Wei-Yue; Li, Yang; Shen, Qi; Cao, Yuan; Li, Feng-Zhi; Wang, Jian-Feng; Huang, Yong-Mei; Deng, Lei; Xi, Tao; Ma, Lu; Hu, Tai; Li, Li; Liu, Nai-Le; Koidl, Franz; Wang, Peiyuan; Chen, Yu-Ao; Wang, Xiang-Bin; Steindorfer, Michael; Kirchner, Georg; Lu, Chao-Yang; Shu, Rong; Ursin, Rupert; Scheidl, Thomas; Peng, Cheng-Zhi; Wang, Jian-Yu; Zeilinger, Anton; Pan, Jian-Wei

2018-01-01

We perform decoy-state quantum key distribution between a low-Earth-orbit satellite and multiple ground stations located in Xinglong, Nanshan, and Graz, which establish satellite-to-ground secure keys with ˜kHz rate per passage of the satellite Micius over a ground station. The satellite thus establishes a secure key between itself and, say, Xinglong, and another key between itself and, say, Graz. Then, upon request from the ground command, Micius acts as a trusted relay. It performs bitwise exclusive or operations between the two keys and relays the result to one of the ground stations. That way, a secret key is created between China and Europe at locations separated by 7600 km on Earth. These keys are then used for intercontinental quantum-secured communication. This was, on the one hand, the transmission of images in a one-time pad configuration from China to Austria as well as from Austria to China. Also, a video conference was performed between the Austrian Academy of Sciences and the Chinese Academy of Sciences, which also included a 280 km optical ground connection between Xinglong and Beijing. Our work clearly confirms the Micius satellite as a robust platform for quantum key distribution with different ground stations on Earth, and points towards an efficient solution for an ultralong-distance global quantum network.

Implementation of rigorous renormalization group method for ground space and low-energy states of local Hamiltonians

NASA Astrophysics Data System (ADS)

Roberts, Brenden; Vidick, Thomas; Motrunich, Olexei I.

2017-12-01

The success of polynomial-time tensor network methods for computing ground states of certain quantum local Hamiltonians has recently been given a sound theoretical basis by Arad et al. [Math. Phys. 356, 65 (2017), 10.1007/s00220-017-2973-z]. The convergence proof, however, relies on "rigorous renormalization group" (RRG) techniques which differ fundamentally from existing algorithms. We introduce a practical adaptation of the RRG procedure which, while no longer theoretically guaranteed to converge, finds matrix product state ansatz approximations to the ground spaces and low-lying excited spectra of local Hamiltonians in realistic situations. In contrast to other schemes, RRG does not utilize variational methods on tensor networks. Rather, it operates on subsets of the system Hilbert space by constructing approximations to the global ground space in a treelike manner. We evaluate the algorithm numerically, finding similar performance to density matrix renormalization group (DMRG) in the case of a gapped nondegenerate Hamiltonian. Even in challenging situations of criticality, large ground-state degeneracy, or long-range entanglement, RRG remains able to identify candidate states having large overlap with ground and low-energy eigenstates, outperforming DMRG in some cases.

Global Precipitation Mission Visualization Tool

NASA Technical Reports Server (NTRS)

Schwaller, Mathew

2011-01-01

The Global Precipitation Mission (GPM) software provides graphic visualization tools that enable easy comparison of ground- and space-based radar observations. It was initially designed to compare ground radar reflectivity from operational, ground-based, S- and C-band meteorological radars with comparable measurements from the Tropical Rainfall Measuring Mission (TRMM) satellite's precipitation radar instrument. This design is also applicable to other groundbased and space-based radars, and allows both ground- and space-based radar data to be compared for validation purposes. The tool creates an operational system that routinely performs several steps. It ingests satellite radar data (precipitation radar data from TRMM) and groundbased meteorological radar data from a number of sources. Principally, the ground radar data comes from national networks of weather radars (see figure). The data ingested by the visualization tool must conform to the data formats used in GPM Validation Network Geometry-matched data product generation. The software also performs match-ups of the radar volume data for the ground- and space-based data, as well as statistical and graphical analysis (including two-dimensional graphical displays) on the match-up data. The visualization tool software is written in IDL, and can be operated either in the IDL development environment or as a stand-alone executable function.

Optimal design of mixed-media packet-switching networks - Routing and capacity assignment

NASA Technical Reports Server (NTRS)

Huynh, D.; Kuo, F. F.; Kobayashi, H.

1977-01-01

This paper considers a mixed-media packet-switched computer communication network which consists of a low-delay terrestrial store-and-forward subnet combined with a low-cost high-bandwidth satellite subnet. We show how to route traffic via ground and/or satellite links by means of static, deterministic procedures and assign capacities to channels subject to a given linear cost such that the network average delay is minimized. Two operational schemes for this network model are investigated: one is a scheme in which the satellite channel is used as a slotted ALOHA channel; the other is a new multiaccess scheme we propose in which whenever a channel collision occurs, retransmission of the involved packets will route through ground links to their destinations. The performance of both schemes is evaluated and compared in terms of cost and average packet delay tradeoffs for some examples. The results offer guidelines for the design and optimal utilization of mixed-media networks.

Observations of Earth space by self-powered stations in Antarctica.

PubMed

Mende, S B; Rachelson, W; Sterling, R; Frey, H U; Harris, S E; McBride, S; Rosenberg, T J; Detrick, D; Doolittle, J L; Engebretson, M; Inan, U; Labelle, J W; Lanzerotti, L J; Weatherwax, A T

2009-12-01

Coupling of the solar wind to the Earth magnetosphere/ionosphere is primarily through the high latitude regions, and there are distinct advantages in making remote sensing observations of these regions with a network of ground-based observatories over other techniques. The Antarctic continent is ideally situated for such a network, especially for optical studies, because the larger offset between geographic and geomagnetic poles in the south enables optical observations at a larger range of magnetic latitudes during the winter darkness. The greatest challenge for such ground-based observations is the generation of power and heat for a sizable ground station that can accommodate an optical imaging instrument. Under the sponsorship of the National Science Foundation, we have developed suitable automatic observing platforms, the Automatic Geophysical Observatories (AGOs) for a network of six autonomous stations on the Antarctic plateau. Each station housed a suite of science instruments including a dual wavelength intensified all-sky camera that records the auroral activity, an imaging riometer, fluxgate and search-coil magnetometers, and ELF/VLF and LM/MF/HF receivers. Originally these stations were powered by propane fuelled thermoelectric generators with the fuel delivered to the site each Antarctic summer. A by-product of this power generation was a large amount of useful heat, which was applied to maintain the operating temperature of the electronics in the stations. Although a reasonable degree of reliability was achieved with these stations, the high cost of the fuel air lift and some remaining technical issues necessitated the development of a different type of power unit. In the second phase of the project we have developed a power generation system using renewable energy that can operate automatically in the Antarctic winter. The most reliable power system consists of a type of wind turbine using a simple permanent magnet rotor and a new type of power control system with variable resistor shunts to regulate the power and dissipate the excess energy and at the same time provide heat for a temperature controlled environment for the instrument electronics and data system. We deployed such systems and demonstrated a high degree of reliability in several years of operation in spite of the relative unpredictability of the Antarctic environment. Sample data are shown to demonstrate that the AGOs provide key measurements, which would be impossible without the special technology developed for this type of observing platform.

Observations of Earth space by self-powered stations in Antarctica

NASA Astrophysics Data System (ADS)

Mende, S. B.; Rachelson, W.; Sterling, R.; Frey, H. U.; Harris, S. E.; McBride, S.; Rosenberg, T. J.; Detrick, D.; Doolittle, J. L.; Engebretson, M.; Inan, U.; Labelle, J. W.; Lanzerotti, L. J.; Weatherwax, A. T.

2009-12-01

Coupling of the solar wind to the Earth magnetosphere/ionosphere is primarily through the high latitude regions, and there are distinct advantages in making remote sensing observations of these regions with a network of ground-based observatories over other techniques. The Antarctic continent is ideally situated for such a network, especially for optical studies, because the larger offset between geographic and geomagnetic poles in the south enables optical observations at a larger range of magnetic latitudes during the winter darkness. The greatest challenge for such ground-based observations is the generation of power and heat for a sizable ground station that can accommodate an optical imaging instrument. Under the sponsorship of the National Science Foundation, we have developed suitable automatic observing platforms, the Automatic Geophysical Observatories (AGOs) for a network of six autonomous stations on the Antarctic plateau. Each station housed a suite of science instruments including a dual wavelength intensified all-sky camera that records the auroral activity, an imaging riometer, fluxgate and search-coil magnetometers, and ELF/VLF and LM/MF/HF receivers. Originally these stations were powered by propane fuelled thermoelectric generators with the fuel delivered to the site each Antarctic summer. A by-product of this power generation was a large amount of useful heat, which was applied to maintain the operating temperature of the electronics in the stations. Although a reasonable degree of reliability was achieved with these stations, the high cost of the fuel air lift and some remaining technical issues necessitated the development of a different type of power unit. In the second phase of the project we have developed a power generation system using renewable energy that can operate automatically in the Antarctic winter. The most reliable power system consists of a type of wind turbine using a simple permanent magnet rotor and a new type of power control system with variable resistor shunts to regulate the power and dissipate the excess energy and at the same time provide heat for a temperature controlled environment for the instrument electronics and data system. We deployed such systems and demonstrated a high degree of reliability in several years of operation in spite of the relative unpredictability of the Antarctic environment. Sample data are shown to demonstrate that the AGOs provide key measurements, which would be impossible without the special technology developed for this type of observing platform.

The Future of Operational Space Weather Observations

NASA Astrophysics Data System (ADS)

Berger, T. E.

2015-12-01

We review the current state of operational space weather observations, the requirements for new or evolved space weather forecasting capablities, and the relevant sections of the new National strategy for space weather developed by the Space Weather Operations, Research, and Mitigation (SWORM) Task Force chartered by the Office of Science and Technology Policy of the White House. Based on this foundation, we discuss future space missions such as the NOAA space weather mission to the L1 Lagrangian point planned for the 2021 time frame and its synergy with an L5 mission planned for the same period; the space weather capabilities of the upcoming GOES-R mission, as well as GOES-Next possiblities; and the upcoming COSMIC-2 mission for ionospheric observations. We also discuss the needs for ground-based operational networks to supply mission critical and/or backup space weather observations including the NSF GONG solar optical observing network, the USAF SEON solar radio observing network, the USGS real-time magnetometer network, the USCG CORS network of GPS receivers, and the possibility of operationalizing the world-wide network of neutron monitors for real-time alerts of ground-level radiation events.

A function approximation approach to anomaly detection in propulsion system test data

NASA Technical Reports Server (NTRS)

Whitehead, Bruce A.; Hoyt, W. A.

1993-01-01

Ground test data from propulsion systems such as the Space Shuttle Main Engine (SSME) can be automatically screened for anomalies by a neural network. The neural network screens data after being trained with nominal data only. Given the values of 14 measurements reflecting external influences on the SSME at a given time, the neural network predicts the expected nominal value of a desired engine parameter at that time. We compared the ability of three different function-approximation techniques to perform this nominal value prediction: a novel neural network architecture based on Gaussian bar basis functions, a conventional back propagation neural network, and linear regression. These three techniques were tested with real data from six SSME ground tests containing two anomalies. The basis function network trained more rapidly than back propagation. It yielded nominal predictions with, a tight enough confidence interval to distinguish anomalous deviations from the nominal fluctuations in an engine parameter. Since the function-approximation approach requires nominal training data only, it is capable of detecting unknown classes of anomalies for which training data is not available.

Ground penetrating radar (GPR) analysis : Phase II field evaluation.

DOT National Transportation Integrated Search

2011-10-01

"The objective of this work was to evaluate the feasibility and value of expanding the MDT's Ground : Penetrating Radar (GPR) program to pavement design and rehabilitation, and to network level : evaluation. Phase I of this project concluded that in ...

Assessing the Accuracy of Ortho-image using Photogrammetric Unmanned Aerial System

NASA Astrophysics Data System (ADS)

Jeong, H. H.; Park, J. W.; Kim, J. S.; Choi, C. U.

2016-06-01

Smart-camera can not only be operated under network environment anytime and any place but also cost less than the existing photogrammetric UAV since it provides high-resolution image, 3D location and attitude data on a real-time basis from a variety of built-in sensors. This study's proposed UAV photogrammetric method, low-cost UAV and smart camera were used. The elements of interior orientation were acquired through camera calibration. The image triangulation was conducted in accordance with presence or absence of consideration of the interior orientation (IO) parameters determined by camera calibration, The Digital Elevation Model (DEM) was constructed using the image data photographed at the target area and the results of the ground control point survey. This study also analyzes the proposed method's application possibility by comparing a Ortho-image the results of the ground control point survey. Considering these study findings, it is suggested that smartphone is very feasible as a payload for UAV system. It is also expected that smartphone may be loaded onto existing UAV playing direct or indirect roles significantly.

Simultaneous scalp electroencephalography (EEG), electromyography (EMG), and whole-body segmental inertial recording for multi-modal neural decoding.

PubMed

Bulea, Thomas C; Kilicarslan, Atilla; Ozdemir, Recep; Paloski, William H; Contreras-Vidal, Jose L

2013-07-26

Recent studies support the involvement of supraspinal networks in control of bipedal human walking. Part of this evidence encompasses studies, including our previous work, demonstrating that gait kinematics and limb coordination during treadmill walking can be inferred from the scalp electroencephalogram (EEG) with reasonably high decoding accuracies. These results provide impetus for development of non-invasive brain-machine-interface (BMI) systems for use in restoration and/or augmentation of gait- a primary goal of rehabilitation research. To date, studies examining EEG decoding of activity during gait have been limited to treadmill walking in a controlled environment. However, to be practically viable a BMI system must be applicable for use in everyday locomotor tasks such as over ground walking and turning. Here, we present a novel protocol for non-invasive collection of brain activity (EEG), muscle activity (electromyography (EMG)), and whole-body kinematic data (head, torso, and limb trajectories) during both treadmill and over ground walking tasks. By collecting these data in the uncontrolled environment insight can be gained regarding the feasibility of decoding unconstrained gait and surface EMG from scalp EEG.

Physical approach to quantum networks with massive particles

NASA Astrophysics Data System (ADS)

Andersen, Molte Emil Strange; Zinner, Nikolaj Thomas

2018-04-01

Assembling large-scale quantum networks is a key goal of modern physics research with applications in quantum information and computation. Quantum wires and waveguides in which massive particles propagate in tailored confinement is one promising platform for realizing a quantum network. In the literature, such networks are often treated as quantum graphs, that is, the wave functions are taken to live on graphs of one-dimensional edges meeting in vertices. Hitherto, it has been unclear what boundary conditions on the vertices produce the physical states one finds in nature. This paper treats a quantum network from a physical approach, explicitly finds the physical eigenstates and compares them to the quantum-graph description. The basic building block of a quantum network is an X-shaped potential well made by crossing two quantum wires, and we consider a massive particle in such an X well. The system is analyzed using a variational method based on an expansion into modes with fast convergence and it provides a very clear intuition for the physics of the problem. The particle is found to have a ground state that is exponentially localized to the center of the X well, and the other symmetric solutions are formed so to be orthogonal to the ground state. This is in contrast to the predictions of the conventionally used so-called Kirchoff boundary conditions in quantum graph theory that predict a different sequence of symmetric solutions that cannot be physically realized. Numerical methods have previously been the only source of information on the ground-state wave function and our results provide a different perspective with strong analytical insights. The ground-state wave function has a spatial profile that looks very similar to the shape of a solitonic solution to a nonlinear Schrödinger equation, enabling an analytical prediction of the wave number. When combining multiple X wells into a network or grid, each site supports a solitonlike localized state. These localized solutions only couple to each other and are able to jump from one site to another as if they were trapped in a discrete lattice.

CRYogenic Orbital TEstbed Ground Test Article Thermal Analysis

NASA Technical Reports Server (NTRS)

Piryk, David; Schallhorn, Paul; Walls, Laurie; Stopnitzky, Benny; Rhys, Noah; Wollen, Mark

2012-01-01

The purpose of this study was to anchor thermal and fluid system models to CRYOTE ground test data. The CRYOTE ground test artide was jointly developed by Innovative Engineering Solutions, United Launch Alliance and NASA KSC. The test article was constructed out of a titanium alloy tank, Sapphire 77 composite skin (similar to G10), an external secondary payload adapter ring, thermal vent system, multi layer insulation and various data acquisition instrumentation. In efforts to understand heat loads throughout this system, the GTA (filled with liquid nitrogen for safety purposes) was subjected to a series of tests in a vacuum chamber at Marshall Space Flight Center. By anchoring analytical models against test data, higher fidelity thermal environment predictions can be made for future flight articles which would eventually demonstrate critical cryogenic fluid management technologies such as system chilldown, transfer, pressure control and long term storage. Significant factors that influenced heat loads included radiative environments, multi-layer insulation performance, tank fill levels and pressures and even contact conductance coefficients. This report demonstrates how analytical thermal/fluid networks were established and includes supporting rationale for specific thermal responses.

Pics d'accélération du mouvement sismique observés lors du séisme de Chichi à Taiwan : application à l'estimation de l'aléa sismiqueAnalysis of peak ground accelerations during the Chichi earthquake, Taiwan: application to seismic hazard evaluation

NASA Astrophysics Data System (ADS)

Chang, Tsui-Yu; Cotton, Fabrice; Angelier, Jacques; Shin, Tzay-Chyn

2001-07-01

Attenuation laws are widely used in order to estimate the peak ground acceleration that may occur at a given locality during an earthquake, for hazard evaluation purposes. However, these simplified laws should be regarded acceptable only in the first approximation, because numerous significant parameters at the local and regional scales are often ignored. We examined the relationship between distance and peak acceleration based on examples from the dense accelerometric network of Taiwan, specifically for the Chichi destructive earthquake. We thus observed significant discrepancies between the predicted and observed accelerations, resulting from (1) near-field saturation, (2) amplification in sedimentary basins, and (3) hanging wall effect. We mapped the residual accelerations (difference between observed and predicted peak ground accelerations). This highlights the role of the regional structure, independently revealed by the geological analysis, as a significant factor that controls the transmission of the seismic accelerations.

Ames life science telescience testbed evaluation

NASA Technical Reports Server (NTRS)

Haines, Richard F.; Johnson, Vicki; Vogelsong, Kristofer H.; Froloff, Walt

1989-01-01

Eight surrogate spaceflight mission specialists participated in a real-time evaluation of remote coaching using the Ames Life Science Telescience Testbed facility. This facility consisted of three remotely located nodes: (1) a prototype Space Station glovebox; (2) a ground control station; and (3) a principal investigator's (PI) work area. The major objective of this project was to evaluate the effectiveness of telescience techniques and hardware to support three realistic remote coaching science procedures: plant seed germinator charging, plant sample acquisition and preservation, and remote plant observation with ground coaching. Each scenario was performed by a subject acting as flight mission specialist, interacting with a payload operations manager and a principal investigator expert. All three groups were physically isolated from each other yet linked by duplex audio and color video communication channels and networked computer workstations. Workload ratings were made by the flight and ground crewpersons immediately after completing their assigned tasks. Time to complete each scientific procedural step was recorded automatically. Two expert observers also made performance ratings and various error assessments. The results are presented and discussed.

Integrated Verification Experiment data collected as part of the Los Alamos National Laboratory's Source Region Program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fitzgerald, T.J.; Carlos, R.C.; Argo, P.E.

As part of the integrated verification experiment (IVE), we deployed a network of hf ionospheric sounders to detect the effects of acoustic waves generated by surface ground motion following underground nuclear tests at the Nevada Test Site. The network sampled up to four geographic locations in the ionosphere from almost directly overhead of the surface ground zero out to a horizontal range of 60 km. We present sample results for four of the IVEs: Misty Echo, Texarkana, Mineral Quarry, and Bexar.

A site evaluation campaign for a ground based atmospheric Cherenkov telescope in Romania

NASA Astrophysics Data System (ADS)

Radu, Aurelian Andrei; Angelescu, Tatiana; Curtef, Valentin; Delia, Florin; Felea, Daniel; Goia, Ioana; Haşegan, Dumitru; Lucaschi, Bogdan; Manea, Ancuta; Popa, Vlad; Raliţă, Ioan; Văcăreanu, Radu

2012-07-01

Around the world, several scientific projects share the interest of a global network of small Cherenkov telescopes for monitoring observations of the brightest blazars—the DWARF network. A small, ground based, imaging atmospheric Cherenkov telescope of last generation is intended to be installed and operated in Romania as a component of the DWARF network. To prepare the construction of the observatory, two support projects have been initiated. Within the framework of these projects, we have assessed a number of possible sites where to settle the observatory. In this paper we submit a brief report on the general characteristics of the best four sites selected after the local infrastructure, the nearby facilities and the social impact criteria have been applied.

Protocol Architecture Model Report

NASA Technical Reports Server (NTRS)

Dhas, Chris

2000-01-01

NASA's Glenn Research Center (GRC) defines and develops advanced technology for high priority national needs in communications technologies for application to aeronautics and space. GRC tasked Computer Networks and Software Inc. (CNS) to examine protocols and architectures for an In-Space Internet Node. CNS has developed a methodology for network reference models to support NASA's four mission areas: Earth Science, Space Science, Human Exploration and Development of Space (REDS), Aerospace Technology. This report applies the methodology to three space Internet-based communications scenarios for future missions. CNS has conceptualized, designed, and developed space Internet-based communications protocols and architectures for each of the independent scenarios. The scenarios are: Scenario 1: Unicast communications between a Low-Earth-Orbit (LEO) spacecraft inspace Internet node and a ground terminal Internet node via a Tracking and Data Rela Satellite (TDRS) transfer; Scenario 2: Unicast communications between a Low-Earth-Orbit (LEO) International Space Station and a ground terminal Internet node via a TDRS transfer; Scenario 3: Multicast Communications (or "Multicasting"), 1 Spacecraft to N Ground Receivers, N Ground Transmitters to 1 Ground Receiver via a Spacecraft.

Network of time-multiplexed optical parametric oscillators as a coherent Ising machine

NASA Astrophysics Data System (ADS)

Marandi, Alireza; Wang, Zhe; Takata, Kenta; Byer, Robert L.; Yamamoto, Yoshihisa

2014-12-01

Finding the ground states of the Ising Hamiltonian maps to various combinatorial optimization problems in biology, medicine, wireless communications, artificial intelligence and social network. So far, no efficient classical and quantum algorithm is known for these problems and intensive research is focused on creating physical systems—Ising machines—capable of finding the absolute or approximate ground states of the Ising Hamiltonian. Here, we report an Ising machine using a network of degenerate optical parametric oscillators (OPOs). Spins are represented with above-threshold binary phases of the OPOs and the Ising couplings are realized by mutual injections. The network is implemented in a single OPO ring cavity with multiple trains of femtosecond pulses and configurable mutual couplings, and operates at room temperature. We programmed a small non-deterministic polynomial time-hard problem on a 4-OPO Ising machine and in 1,000 runs no computational error was detected.

Discrete gravity on random tensor network and holographic Rényi entropy

NASA Astrophysics Data System (ADS)

Han, Muxin; Huang, Shilin

2017-11-01

In this paper we apply the discrete gravity and Regge calculus to tensor networks and Anti-de Sitter/conformal field theory (AdS/CFT) correspondence. We construct the boundary many-body quantum state |Ψ〉 using random tensor networks as the holographic mapping, applied to the Wheeler-deWitt wave function of bulk Euclidean discrete gravity in 3 dimensions. The entanglement Rényi entropy of |Ψ〉 is shown to holographically relate to the on-shell action of Einstein gravity on a branch cover bulk manifold. The resulting Rényi entropy S n of |Ψ〉 approximates with high precision the Rényi entropy of ground state in 2-dimensional conformal field theory (CFT). In particular it reproduces the correct n dependence. Our results develop the framework of realizing the AdS3/CFT2 correspondence on random tensor networks, and provide a new proposal to approximate the CFT ground state.

Deep Space Network and Lunar Network Communication Coverage of the Moon

NASA Technical Reports Server (NTRS)

Lee, Charles H.; Cheung, Kar-Ming

2006-01-01

In this article, we describe the communication coverage analysis for the lunar network and the Earth ground stations. The first part of this article focuses on the direct communication coverage of the Moon from the Earth's ground stations. In particular, we assess the coverage performance of the Moon based on the existing Deep Space Network (DSN) antennas and the complimentary coverage of other potential stations at Hartebeesthoek, South Africa and at Santiago, Chile. We also address the coverage sensitivity based on different DSN antenna scenarios and their capability to provide single and redundant coverage of the Moon. The second part of this article focuses on the framework of the constrained optimization scheme to seek a stable constellation six relay satellites in two planes that not only can provide continuous communication coverage to any users on the Moon surface, but can also deliver data throughput in a highly efficient manner.

Ground-state coding in partially connected neural networks

NASA Technical Reports Server (NTRS)

Baram, Yoram

1989-01-01

Patterns over (-1,0,1) define, by their outer products, partially connected neural networks, consisting of internally strongly connected, externally weakly connected subnetworks. The connectivity patterns may have highly organized structures, such as lattices and fractal trees or nests. Subpatterns over (-1,1) define the subcodes stored in the subnetwork, that agree in their common bits. It is first shown that the code words are locally stable stares of the network, provided that each of the subcodes consists of mutually orthogonal words or of, at most, two words. Then it is shown that if each of the subcodes consists of two orthogonal words, the code words are the unique ground states (absolute minima) of the Hamiltonian associated with the network. The regions of attraction associated with the code words are shown to grow with the number of subnetworks sharing each of the neurons. Depending on the particular network architecture, the code sizes of partially connected networks can be vastly greater than those of fully connected ones and their error correction capabilities can be significantly greater than those of the disconnected subnetworks. The codes associated with lattice-structured and hierarchical networks are discussed in some detail.

A Deep Neural Network Model for Rainfall Estimation UsingPolarimetric WSR-88DP Radar Observations

NASA Astrophysics Data System (ADS)

Tan, H.; Chandra, C. V.; Chen, H.

2016-12-01

Rainfall estimation based on radar measurements has been an important topic for a few decades. Generally, radar rainfall estimation is conducted through parametric algorisms such as reflectivity-rainfall relation (i.e., Z-R relation). On the other hand, neural networks are developed for ground rainfall estimation based on radar measurements. This nonparametric method, which takes into account of both radar observations and rainfall measurements from ground rain gauges, has been demonstrated successfully for rainfall rate estimation. However, the neural network-based rainfall estimation is limited in practice due to the model complexity and structure, data quality, as well as different rainfall microphysics. Recently, the deep learning approach has been introduced in pattern recognition and machine learning areas. Compared to traditional neural networks, the deep learning based methodologies have larger number of hidden layers and more complex structure for data representation. Through a hierarchical learning process, the high level structured information and knowledge can be extracted automatically from low level features of the data. In this paper, we introduce a novel deep neural network model for rainfall estimation based on ground polarimetric radar measurements .The model is designed to capture the complex abstractions of radar measurements at different levels using multiple layers feature identification and extraction. The abstractions at different levels can be used independently or fused with other data resource such as satellite-based rainfall products and/or topographic data to represent the rain characteristics at certain location. In particular, the WSR-88DP radar and rain gauge data collected in Dallas - Fort Worth Metroplex and Florida are used extensively to train the model, and for demonstration purposes. Quantitative evaluation of the deep neural network based rainfall products will also be presented, which is based on an independent rain gauge network.

Novel Method for Detection of Air Pollution using Cellular Communication Networks

NASA Astrophysics Data System (ADS)

David, N.; Gao, O. H.

2016-12-01

Air pollution can lead to a wide spectrum of severe and chronic health impacts. Conventional tools for monitoring the phenomenon do not provide a sufficient monitoring solution in a global scale since they are, for example, not representative of the larger space or due to limited deployment as a result of practical limitations, such as: acquisition, installation, and ongoing maintenance costs. Near ground temperature inversions are directly identified with air pollution events since they suppress vertical atmospheric movement and trap pollutants near the ground. Wireless telecommunication links that comprise the data transfer infrastructure in cellular communication networks operate at frequencies of tens of GHz and are affected by different atmospheric phenomena. These systems are deployed near ground level across the globe, including in developing countries such as India, countries in Africa, etc. Many cellular providers routinely store data regarding the received signal levels in the network for quality assurance needs. Temperature inversions cause atmospheric layering, and change the refractive index of the air when compared to standard conditions. As a result, the ducts that are formed can operate, in essence, as atmospheric wave guides, and cause interference (signal amplification / attenuation) in the microwaves measured by the wireless network. Thus, this network is in effect, an existing system of environmental sensors for monitoring temperature inversions and the episodes of air pollution identified with them. This work presents the novel idea, and demonstrates it, in operation, over several events of air pollution which were detected by a standard cellular communication network during routine operation. Reference: David, N. and Gao, H.O. Using cellular communication networks to detect air pollution, Environmental Science & Technology, 2016 (accepted).

Networked sensors for the combat forces

NASA Astrophysics Data System (ADS)

Klager, Gene

2004-11-01

Real-time and detailed information is critical to the success of ground combat forces. Current manned reconnaissance, surveillance, and target acquisition (RSTA) capabilities are not sufficient to cover battlefield intelligence gaps, provide Beyond-Line-of-Sight (BLOS) targeting, and the ambush avoidance information necessary for combat forces operating in hostile situations, complex terrain, and conducting military operations in urban terrain. This paper describes a current US Army program developing advanced networked unmanned/unattended sensor systems to survey these gaps and provide the Commander with real-time, pertinent information. Networked Sensors for the Combat Forces plans to develop and demonstrate a new generation of low cost distributed unmanned sensor systems organic to the RSTA Element. Networked unmanned sensors will provide remote monitoring of gaps, will increase a unit"s area of coverage, and will provide the commander organic assets to complete his Battlefield Situational Awareness (BSA) picture for direct and indirect fire weapons, early warning, and threat avoidance. Current efforts include developing sensor packages for unmanned ground vehicles, small unmanned aerial vehicles, and unattended ground sensors using advanced sensor technologies. These sensors will be integrated with robust networked communications and Battle Command tools for mission planning, intelligence "reachback", and sensor data management. The network architecture design is based on a model that identifies a three-part modular design: 1) standardized sensor message protocols, 2) Sensor Data Management, and 3) Service Oriented Architecture. This simple model provides maximum flexibility for data exchange, information management and distribution. Products include: Sensor suites optimized for unmanned platforms, stationary and mobile versions of the Sensor Data Management Center, Battle Command planning tools, networked communications, and sensor management software. Details of these products and recent test results will be presented.

Network measures predict neuropsychological outcome after brain injury

PubMed Central

Warren, David E.; Power, Jonathan D.; Bruss, Joel; Denburg, Natalie L.; Waldron, Eric J.; Sun, Haoxin; Petersen, Steven E.; Tranel, Daniel

2014-01-01

Hubs are network components that hold positions of high importance for network function. Previous research has identified hubs in human brain networks derived from neuroimaging data; however, there is little consensus on the localization of such hubs. Moreover, direct evidence regarding the role of various proposed hubs in network function (e.g., cognition) is scarce. Regions of the default mode network (DMN) have been frequently identified as “cortical hubs” of brain networks. On theoretical grounds, we have argued against some of the methods used to identify these hubs and have advocated alternative approaches that identify different regions of cortex as hubs. Our framework predicts that our proposed hub locations may play influential roles in multiple aspects of cognition, and, in contrast, that hubs identified via other methods (including salient regions in the DMN) might not exert such broad influence. Here we used a neuropsychological approach to directly test these predictions by studying long-term cognitive and behavioral outcomes in 30 patients, 19 with focal lesions to six “target” hubs identified by our approaches (high system density and participation coefficient) and 11 with focal lesions to two “control” hubs (high degree centrality). In support of our predictions, we found that damage to target locations produced severe and widespread cognitive deficits, whereas damage to control locations produced more circumscribed deficits. These findings support our interpretation of how neuroimaging-derived network measures relate to cognition and augment classic neuroanatomically based predictions about cognitive and behavioral outcomes after focal brain injury. PMID:25225403

A systematic analysis of directional site effects at stations of the Italian Seismic Network to test the role of local topography

NASA Astrophysics Data System (ADS)

Pischiutta, Marta; Cianfarra, Paola; Salvini, Francesco; Cara, Fabrizio; Vannoli, Paola

2018-03-01

Directional site effects observed at seismological stations on pronounced relief are analyzed. We investigate the ground motion properties calculating horizontal-to-vertical spectral ratios and horizontal polarization of both ambient vibrations and earthquake records using broadband seismograms of the Italian Seismic Network. We find that a subset of 47 stations with pronounced relief, results in a significant (>2) directional amplification of the horizontal component, with a well defined, site-specific direction of motion. However, the horizontal spectral response of sites is not uniform, varying from an isolated (resonant) frequency peak to a broadband amplification, interesting frequency bands as large as 1-10 Hz in many cases. Using the 47 selected stations, we have tried to establish a relation between directional amplification and topography geometry in a 2D-vision, when applicable, through a morphological analysis of the Digital Elevation Model using Geographic Information Systems. The procedure computes the parameters that characterize the geometry of topographic irregularities (size and slope), in combination with a principal component analysis that automatically yields the orientation of the elongated ridges. In seeking a relation between directional amplification and the surface morphology, we have found that it is impossible to fit the variety of observations with a resonant topography model as well as to identify common features in the ground motion behavior for stations with similar topography typologies. We conclude that, rather than the shape of the topography, local structural complexities and details of the near-surface structure must play a predominant role in controlling ground motion properties at sites with pronounced relief.

A systematic analysis of directional site effects at stations of the Italian seismic network to test the role of local topography

NASA Astrophysics Data System (ADS)

Pischiutta, Marta; Cianfarra, Paola; Salvini, Francesco; Cara, Fabrizio; Vannoli, Paola

2018-07-01

Directional site effects observed at seismological stations on pronounced relief are analysed. We investigate the ground motion properties calculating horizontal-to-vertical spectral ratios and horizontal polarization of both ambient vibrations and earthquake records using broad-band seismograms of the Italian seismic network. We find that a subset of 47 stations with pronounced relief results in a significant (>2) directional amplification of the horizontal component, with a well-defined, site-specific direction of motion. However, the horizontal spectral response of sites is not uniform, varying from an isolated (resonant) frequency peak to a broad-band amplification, interesting frequency bands as large as 1-10 Hz in many cases. Using 47 selected stations, we have tried to establish a relation between directional amplification and topography geometry in a 2-D vision, when applicable, through a morphological analysis of the digital elevation model using geographic information systems. The procedure computes the parameters that characterize the geometry of topographic irregularities (size and slope), in combination with a principal component analysis that automatically yields the orientation of the elongated ridges. In seeking a relation between directional amplification and the surface morphology, we have found that it is impossible to fit the variety of observations with a resonant topography model as well as to identify common features in the ground motion behaviour for stations with similar topography typologies. We conclude that, rather than the shape of the topography, local structural complexities and details of the near-surface structure must play a predominant role in controlling ground motion properties at sites with pronounced relief.

Bootstrapping on Undirected Binary Networks Via Statistical Mechanics

NASA Astrophysics Data System (ADS)

Fushing, Hsieh; Chen, Chen; Liu, Shan-Yu; Koehl, Patrice

2014-09-01

We propose a new method inspired from statistical mechanics for extracting geometric information from undirected binary networks and generating random networks that conform to this geometry. In this method an undirected binary network is perceived as a thermodynamic system with a collection of permuted adjacency matrices as its states. The task of extracting information from the network is then reformulated as a discrete combinatorial optimization problem of searching for its ground state. To solve this problem, we apply multiple ensembles of temperature regulated Markov chains to establish an ultrametric geometry on the network. This geometry is equipped with a tree hierarchy that captures the multiscale community structure of the network. We translate this geometry into a Parisi adjacency matrix, which has a relative low energy level and is in the vicinity of the ground state. The Parisi adjacency matrix is then further optimized by making block permutations subject to the ultrametric geometry. The optimal matrix corresponds to the macrostate of the original network. An ensemble of random networks is then generated such that each of these networks conforms to this macrostate; the corresponding algorithm also provides an estimate of the size of this ensemble. By repeating this procedure at different scales of the ultrametric geometry of the network, it is possible to compute its evolution entropy, i.e. to estimate the evolution of its complexity as we move from a coarse to a fine description of its geometric structure. We demonstrate the performance of this method on simulated as well as real data networks.

Performance of Earthquake Early Warning Systems during the Major Events of the 2016-2017 Central Italy Seismic Sequence.

NASA Astrophysics Data System (ADS)

Festa, G.; Picozzi, M.; Alessandro, C.; Colombelli, S.; Cattaneo, M.; Chiaraluce, L.; Elia, L.; Martino, C.; Marzorati, S.; Supino, M.; Zollo, A.

2017-12-01

Earthquake early warning systems (EEWS) are systems nowadays contributing to the seismic risk mitigation actions, both in terms of losses and societal resilience, by issuing an alert promptly after the earthquake origin and before the ground shaking impacts the targets to be protected. EEWS systems can be grouped in two main classes: network based and stand-alone systems. Network based EEWS make use of dense seismic networks surrounding the fault (e.g. Near Fault Observatory; NFO) generating the event. The rapid processing of the P-wave early portion allows for the location and magnitude estimation of the event then used to predict the shaking through ground motion prediction equations. Stand-alone systems instead analyze the early P-wave signal to predict the ground shaking carried by the late S or surface waves, through empirically calibrated scaling relationships, at the recording site itself. We compared the network-based (PRESTo, PRobabilistic and Evolutionary early warning SysTem, www.prestoews.org, Satriano et al., 2011) and the stand-alone (SAVE, on-Site-Alert-leVEl, Caruso et al., 2017) systems, by analyzing their performance during the 2016-2017 Central Italy sequence. We analyzed 9 earthquakes having magnitude 5.0 < M < 6.5 at about 200 stations located within 200 km from the epicentral area, including stations of The Altotiberina NFO (TABOO). Performances are evaluated in terms of rate of success of ground shaking intensity prediction and available lead-time, i.e. the time available for security actions. PRESTo also evaluated the accuracy of location and magnitude. Both systems well predict the ground shaking nearby the event source, with a success rate around 90% within the potential damage zone. The lead-time is significantly larger for the network based system, increasing to more than 10s at 40 km from the event epicentre. The stand-alone system better performs in the near-source region showing a positive albeit small lead-time (<3s). Far away from the source, the performances slightly degrade, mostly owing to uncertain calibration of attenuation relationships. This study opens to the possibility of making EEWS operational in Italy, based on the available acceleration networks, by improving the capability of reducing the lead-time related to data telemetry.

Embedded parallel processing based ground control systems for small satellite telemetry

NASA Technical Reports Server (NTRS)

Forman, Michael L.; Hazra, Tushar K.; Troendly, Gregory M.; Nickum, William G.

1994-01-01

The use of networked terminals which utilize embedded processing techniques results in totally integrated, flexible, high speed, reliable, and scalable systems suitable for telemetry and data processing applications such as mission operations centers (MOC). Synergies of these terminals, coupled with the capability of terminal to receive incoming data, allow the viewing of any defined display by any terminal from the start of data acquisition. There is no single point of failure (other than with network input) such as exists with configurations where all input data goes through a single front end processor and then to a serial string of workstations. Missions dedicated to NASA's ozone measurements program utilize the methodologies which are discussed, and result in a multimission configuration of low cost, scalable hardware and software which can be run by one flight operations team with low risk.

Seismic Hazard Analysis as a Controlling Technique of Induced Seismicity in Geothermal Systems

NASA Astrophysics Data System (ADS)

Convertito, V.; Sharma, N.; Maercklin, N.; Emolo, A.; Zollo, A.

2011-12-01

The effect of induced seismicity of geothermal systems during stimulation and fluid circulation can cover a wide range of values from light and unfelt to severe and damaging. If the design of a modern geothermal system requires the largest efficiency to be obtained from the social point of view it is required that the system could be managed in order to reduce possible impact in advance. In this framework, automatic control of the seismic response of the stimulated reservoir is nowadays mandatory, particularly in proximity of densely populated areas. Recently, techniques have been proposed for this purpose mainly based on the concept of the traffic light. This system provides a tool to decide the level of stimulation rate based on the real-time analysis of the induced seismicity and the ongoing ground motion values. However, in some cases the induced effect can be delayed with respect to the time when the reservoir is stimulated. Thus, a controlling system technique able to estimate the ground motion levels for different time scales can help to better control the geothermal system. Here we present an adaptation of the classical probabilistic seismic hazard analysis to the case where the seismicity rate as well as the propagation medium properties are not constant with time. We use a non-homogeneous seismicity model for modeling purposes, in which the seismicity rate and b-value of the recurrence relationship change with time. Additionally, as a further controlling procedure, we propose a moving time window analysis of the recorded peak ground-motion values aimed at monitoring the changes in the propagation medium. In fact, for the same set of magnitude values recorded at the same stations, we expect that on average peak ground motion values attenuate in same way. As a consequence, the residual differences can be reasonably ascribed to changes in medium properties. These changes can be modeled and directly introduced in the hazard integral. We applied the proposed technique to a training dataset of induced earthquakes recorded by Berkeley-Geysers network, which is installed in The Geysers geothermal area in Northern California. The reliability of the techniques is then tested by using a different dataset performing seismic hazard analysis in a time-evolving approach, which provides with ground-motion values having fixed probabilities of exceedence. Those values can be finally compared with the observations by using appropriate statistical tests.

Suppression of Adverse Effects of GIC Using Controlled Variable Grounding Resistor

NASA Astrophysics Data System (ADS)

Abuhussein, A.; Ali, M. H.

2016-12-01

Geomagnetically induced current (GIC) has a harmful impact on power systems, with a large footprint. Mitigation strategies for the GIC are required to protect the integrity of the power system. To date, the adverse effects of GIC are being mitigated by either operational procedures or grounding fixed capacitors (GFCs). The operational procedures are uncertain, reduce systems' reliability, and increase energy losses. On the other hand, GFCs, incur voltage spikes, increase the transformer cost substantially, and require protection circuitry. This study investigates new possible approaches to cope with GIC, by using a controlled variable grounding resistor (CVGR), without interfering with the system's normal operation. In addition, the new techniques help suppress unsymmetrical faults in the power network. The controllability of the grounding resistor is applied using three different techniques: (1) a Parallel switch that is controlled by PI regulated duty cycle, (2) a Parallel switch that is triggered by a preset values in a look-up-table (LUT), and (3) a Mechanical resistor varied by a Fuzzy logic controller (FLC). The experimental results were obtained and validated using the MATLAB/SIMULINK software. A hypothetical power system that consists of a generator, a 765kv, 500 km long transmission lines connecting between a step-up, Δ-Yn, transformer, and a step-down, Yn-Δ, transformer, is considered. The performance of the CVGR is compared with that of the GFC under the cases of GIC event and unsymmetrical faults. From the simulation results, the following points are concluded: The CVGR effectively suppresses the GIC flowing in the system. Consequently, it protects the transformers from saturation and the rest of the system from collapsing. The CVGR also reduces the voltage and power swings associated with unsymmetrical faults and blocks the zero sequence current flowing through the neutral of the transformer. The performance of the CVGR surpasses that of the GFC in terms of GIC/fault current magnitude and decay time reduction. The GFC violates the IEEE standards C57.32/ C57.12 of transformers insulation level, while the CVGR maintain the neutral to ground voltage within acceptable levels. The CVGR, as opposed to the GFC, does not require a discharge circuit (spark gap), thus it reduces the cost and complexity.

COST Action TU1206 "SUB-URBAN - A European network to improve understanding and use of the ground beneath our cities"

NASA Astrophysics Data System (ADS)

Campbell, Diarmad; de Beer, Johannes; Lawrence, David; van der Meulen, Michiel; Mielby, Susie; Hay, David; Scanlon, Ray; Campenhout, Ignace; Taugs, Renate; Eriksson, Ingelov

2014-05-01

Sustainable urbanisation is the focus of SUB-URBAN, a European Cooperation in Science and Technology (COST) Action TU1206 - A European network to improve understanding and use of the ground beneath our cities. This aims to transform relationships between experts who develop urban subsurface geoscience knowledge - principally national Geological Survey Organisations (GSOs), and those who can most benefit from it - urban decision makers, planners, practitioners and the wider research community. Under COST's Transport and Urban Development Domain, SUB-URBAN has established a network of GSOs and other researchers in over 20 countries, to draw together and evaluate collective urban geoscience research in 3D/4D characterisation, prediction and visualisation. Knowledge exchange between researchers and City-partners within 'SUB-URBAN' is already facilitating new city-scale subsurface projects, and is developing a tool-box of good-practice guidance, decision-support tools, and cost-effective methodologies that are appropriate to local needs and circumstances. These are intended to act as catalysts in the transformation of relationships between geoscientists and urban decision-makers more generally. As a result, the importance of the urban sub-surface in the sustainable development of our cities will be better appreciated, and the conflicting demands currently placed on it will be acknowledged, and resolved appropriately. Existing city-scale 3D/4D model exemplars are being developed by partners in the UK (Glasgow, London), Germany (Hamburg) and France (Paris). These draw on extensive ground investigation (10s-100s of thousands of boreholes) and other data. Model linkage enables prediction of groundwater, heat, SuDS, and engineering properties. Combined subsurface and above-ground (CityGML, BIMs) models are in preparation. These models will provide valuable tools for more holistic urban planning; identifying subsurface opportunities and saving costs by reducing uncertainty in ground conditions. A key area of interest, and one of potential collaboration with COST Action TU1208, is in characterising and parameterising the very near urban subsurface, and especially the anthropogenic deposits, to assist decision-making by civil engineers, and others. Anthropogenic deposits may be many metres thick, are typically very heterogeneous, have complex histories of accumulation, and may including important archaeological assets. They display complex stratigraphies which are difficult to resolve using traditional methodologies, even with extensive invasive ground investigation. Ground Penetrating Radar, and other non-destructive methods of ground investigation hold considerable promise in greatly improving the resolution, understanding, and modelling, of these and other near-surface deposits in particular. This work is a contribution both to COST Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar" and to COST Action TU1206 "SUB-URBAN - A European network to improve understanding and use of the ground beneath our cities"

Epistemic brokerage in the bio-property narrative: contributions to explaining opposition to transgenic technologies in agriculture.

PubMed

Herring, Ronald J

2010-11-30

Unlike some global contentions - abolition of slavery, or universal franchise, for example - the rift over rDNA crops is not about ultimate values. Improvement of farmer welfare and enhanced sustainability of agriculture are universally valued goals. However, means to those ends are politically disputed; that dispute depends on alternative empirical stories about biotechnology, sometimes even alternative epistemologies. Opposition revolves around two fundamental dimensions: bio-safety and bio-property. There is convergence of these dimensions around exceptional risk and vulnerability to corporate control of farmers, but these are analytically separable questions of fact. This paper concentrates on bio-property. Epistemic brokers have successfully established knowledge claims that simultaneously undermine the case for rDNA technologies as potential contributors to development and motivate opposition. Epistemic brokers command authority from their positions at junctures of networks, enabling the screening, weighting, theorizing and diffusion of contentious empirical accounts. In contentions of low information, high information costs and diffuse anxiety, these claims provide cognitive support for opposition to 'GMOs'. Specifically, claims of patents, monopoly corporate control and terminator technology have diffused to and from India in global networks. Though effective in transnational advocacy networks, these claims have proved either false or inconsistent with dynamics on the ground. Copyright © 2010 Elsevier B.V. All rights reserved.

Simulation of the Regional Ground-Water-Flow System and Ground-Water/Surface-Water Interaction in the Rock River Basin, Wisconsin

USGS Publications Warehouse

Juckem, Paul F.

2009-01-01

A regional, two-dimensional, areal ground-water-flow model was developed to simulate the ground-water-flow system and ground-water/surface-water interaction in the Rock River Basin. The model was developed by the U.S. Geological Survey (USGS), in cooperation with the Rock River Coalition. The objectives of the regional model were to improve understanding of the ground-water-flow system and to develop a tool suitable for evaluating the effects of potential regional water-management programs. The computer code GFLOW was used because of the ease with which the model can simulate ground-water/surface-water interactions, provide a framework for simulating regional ground-water-flow systems, and be refined in a stepwise fashion to incorporate new data and simulate ground-water-flow patterns at multiple scales. The ground-water-flow model described in this report simulates the major hydrogeologic features of the modeled area, including bedrock and surficial aquifers, ground-water/surface-water interactions, and ground-water withdrawals from high-capacity wells. The steady-state model treats the ground-water-flow system as a single layer with hydraulic conductivity and base elevation zones that reflect the distribution of lithologic groups above the Precambrian bedrock and a regionally significant confining unit, the Maquoketa Formation. In the eastern part of the Basin where the shale-rich Maquoketa Formation is present, deep ground-water flow in the sandstone aquifer below the Maquoketa Formation was not simulated directly, but flow into this aquifer was incorporated into the GFLOW model from previous work in southeastern Wisconsin. Recharge was constrained primarily by stream base-flow estimates and was applied uniformly within zones guided by regional infiltration estimates for soils. The model includes average ground-water withdrawals from 1997 to 2006 for municipal wells and from 1997 to 2005 for high-capacity irrigation, industrial, and commercial wells. In addition, the model routes tributary base flow through the river network to the Rock River. The parameter-estimation code PEST was linked to the GFLOW model to select the combination of parameter values best able to match more than 8,000 water-level measurements and base-flow estimates at 9 streamgages. Results from the calibrated GFLOW model show simulated (1) ground-water-flow directions, (2) ground-water/surface-water interactions, as depicted in a map of gaining and losing river and lake sections, (3) ground-water contributing areas for selected tributary rivers, and (4) areas of relatively local ground water captured by rivers. Ground-water flow patterns are controlled primarily by river geometries, with most river sections gaining water from the ground-water-flow system; losing sections are most common on the downgradient shore of lakes and reservoirs or near major pumping centers. Ground-water contributing areas to tributary rivers generally coincide with surface watersheds; however the locations of ground-water divides are controlled by the water table, whereas surface-water divides are controlled by surface topography. Finally, areas of relatively local ground water captured by rivers generally extend upgradient from rivers but are modified by the regional flow pattern, such that these areas tend to shift toward regional ground-water divides for relatively small rivers. It is important to recognize the limitations of this regional-scale model. Heterogeneities in subsurface properties and in recharge rates are considered only at a very broad scale (miles to tens of miles). No account is taken of vertical variations in properties or pumping rates, and no provision is made to account for stacked ground-water-flow systems that have different flow patterns at different depths. Small-scale flow systems (hundreds to thousands of feet) associated with minor water bodies are not considered; as a result, the model is not currently designed for simulating site-specifi

An Optimum Space-to-Ground Communication Concept for CubeSat Platform Utilizing NASA Space Network and Near Earth Network

NASA Technical Reports Server (NTRS)

Wong, Yen F.; Kegege, Obadiah; Schaire, Scott H.; Bussey, George; Altunc, Serhat; Zhang, Yuwen; Patel Chitra

2016-01-01

National Aeronautics and Space Administration (NASA) CubeSat missions are expected to grow rapidly in the next decade. Higher data rate CubeSats are transitioning away from Amateur Radio bands to higher frequency bands. A high-level communication architecture for future space-to-ground CubeSat communication was proposed within NASA Goddard Space Flight Center. This architecture addresses CubeSat direct-to-ground communication, CubeSat to Tracking Data Relay Satellite System (TDRSS) communication, CubeSat constellation with Mothership direct-to-ground communication, and CubeSat Constellation with Mothership communication through K-Band Single Access (KSA). A study has been performed to explore this communication architecture, through simulations, analyses, and identifying technologies, to develop the optimum communication concepts for CubeSat communications. This paper presents details of the simulation and analysis that include CubeSat swarm, daughter ship/mother ship constellation, Near Earth Network (NEN) S and X-band direct to ground link, TDRSS Multiple Access (MA) array vs Single Access mode, notional transceiver/antenna configurations, ground asset configurations and Code Division Multiple Access (CDMA) signal trades for daughter ship/mother ship CubeSat constellation inter-satellite cross link. Results of space science X-band 10 MHz maximum achievable data rate study are summarized. CubeSat NEN Ka-Band end-to-end communication analysis is provided. Current CubeSat communication technologies capabilities are presented. Compatibility test of the CubeSat transceiver through NEN and SN is discussed. Based on the analyses, signal trade studies and technology assessments, the desired CubeSat transceiver features and operation concepts for future CubeSat end-to-end communications are derived.

Cone penetrometer testing and discrete-depth ground water sampling techniques: A cost-effective method of site characterization in a multiple-aquifer setting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zemo, D.A.; Pierce, Y.G.; Gallinatti, J.D.

Cone penetrometer testing (CPT), combined with discrete-depth ground water sampling methods, can significantly reduce the time and expense required to characterize large sites that have multiple aquifers. Results from the screening site characterization can then be used to design and install a cost-effective monitoring well network. At a site in northern California, it was necessary to characterize the stratigraphy and the distribution of volatile organic compounds (VOCs). To expedite characterization, a five-week field screening program was implemented that consisted of a shallow ground water survey, CPT soundings and pore-pressure measurements, and discrete-depth ground water sampling. Based on continuous lithologic informationmore » provided by the CPT soundings, four predominantly coarse-grained, water yielding stratigraphic packages were identified. Seventy-nine discrete-depth ground water samples were collected using either shallow ground water survey techniques, the BAT Enviroprobe, or the QED HydroPunch I, depending on subsurface conditions. Using results from these efforts, a 20-well monitoring network was designed and installed to monitor critical points within each stratigraphic package. Good correlation was found for hydraulic head and chemical results between discrete-depth screening data and monitoring well data. Understanding the vertical VOC distribution and concentrations produced substantial time and cost savings by minimizing the number of permanent monitoring wells and reducing the number of costly conductor casings that had to be installed. Additionally, significant long-term cost savings will result from reduced sampling costs, because fewer wells comprise the monitoring network. The authors estimate these savings to be 50% for site characterization costs, 65% for site characterization time, and 60% for long-term monitoring costs.« less

Ground-based instruments of the PWING project to investigate dynamics of the inner magnetosphere at subauroral latitudes as a part of the ERG-ground coordinated observation network

NASA Astrophysics Data System (ADS)

Shiokawa, Kazuo; Katoh, Yasuo; Hamaguchi, Yoshiyuki; Yamamoto, Yuka; Adachi, Takumi; Ozaki, Mitsunori; Oyama, Shin-Ichiro; Nosé, Masahito; Nagatsuma, Tsutomu; Tanaka, Yoshimasa; Otsuka, Yuichi; Miyoshi, Yoshizumi; Kataoka, Ryuho; Takagi, Yuki; Takeshita, Yuhei; Shinbori, Atsuki; Kurita, Satoshi; Hori, Tomoaki; Nishitani, Nozomu; Shinohara, Iku; Tsuchiya, Fuminori; Obana, Yuki; Suzuki, Shin; Takahashi, Naoko; Seki, Kanako; Kadokura, Akira; Hosokawa, Keisuke; Ogawa, Yasunobu; Connors, Martin; Michael Ruohoniemi, J.; Engebretson, Mark; Turunen, Esa; Ulich, Thomas; Manninen, Jyrki; Raita, Tero; Kero, Antti; Oksanen, Arto; Back, Marko; Kauristie, Kirsti; Mattanen, Jyrki; Baishev, Dmitry; Kurkin, Vladimir; Oinats, Alexey; Pashinin, Alexander; Vasilyev, Roman; Rakhmatulin, Ravil; Bristow, William; Karjala, Marty

2017-11-01

The plasmas (electrons and ions) in the inner magnetosphere have wide energy ranges from electron volts to mega-electron volts (MeV). These plasmas rotate around the Earth longitudinally due to the gradient and curvature of the geomagnetic field and by the co-rotation motion with timescales from several tens of hours to less than 10 min. They interact with plasma waves at frequencies of mHz to kHz mainly in the equatorial plane of the magnetosphere, obtain energies up to MeV, and are lost into the ionosphere. In order to provide the global distribution and quantitative evaluation of the dynamical variation of these plasmas and waves in the inner magnetosphere, the PWING project (study of dynamical variation of particles and waves in the inner magnetosphere using ground-based network observations, http://www.isee.nagoya-u.ac.jp/dimr/PWING/) has been carried out since April 2016. This paper describes the stations and instrumentation of the PWING project. We operate all-sky airglow/aurora imagers, 64-Hz sampling induction magnetometers, 40-kHz sampling loop antennas, and 64-Hz sampling riometers at eight stations at subauroral latitudes ( 60° geomagnetic latitude) in the northern hemisphere, as well as 100-Hz sampling EMCCD cameras at three stations. These stations are distributed longitudinally in Canada, Iceland, Finland, Russia, and Alaska to obtain the longitudinal distribution of plasmas and waves in the inner magnetosphere. This PWING longitudinal network has been developed as a part of the ERG (Arase)-ground coordinated observation network. The ERG (Arase) satellite was launched on December 20, 2016, and has been in full operation since March 2017. We will combine these ground network observations with the ERG (Arase) satellite and global modeling studies. These comprehensive datasets will contribute to the investigation of dynamical variation of particles and waves in the inner magnetosphere, which is one of the most important research topics in recent space physics, and the outcome of our research will improve safe and secure use of geospace around the Earth.[Figure not available: see fulltext.

Data and Network Science for Noisy Heterogeneous Systems

ERIC Educational Resources Information Center

Rider, Andrew Kent

2013-01-01

Data in many growing fields has an underlying network structure that can be taken advantage of. In this dissertation we apply data and network science to problems in the domains of systems biology and healthcare. Data challenges in these fields include noisy, heterogeneous data, and a lack of ground truth. The primary thesis of this work is that…

Systematic observations of the slip pulse properties of large earthquake ruptures

USGS Publications Warehouse

Melgar, Diego; Hayes, Gavin

2017-01-01

In earthquake dynamics there are two end member models of rupture: propagating cracks and self-healing pulses. These arise due to different properties of faults and have implications for seismic hazard; rupture mode controls near-field strong ground motions. Past studies favor the pulse-like mode of rupture; however, due to a variety of limitations, it has proven difficult to systematically establish their kinematic properties. Here we synthesize observations from a database of >150 rupture models of earthquakes spanning M7–M9 processed in a uniform manner and show the magnitude scaling properties of these slip pulses indicates self-similarity. Further, we find that large and very large events are statistically distinguishable relatively early (at ~15 s) in the rupture process. This suggests that with dense regional geophysical networks strong ground motions from a large rupture can be identified before their onset across the source region.

Selected hydrologic data for the field demonstration of three permeable reactive barriers near Fry Canyon, Utah, 1996-2000

USGS Publications Warehouse

Wilkowske, Chris D.; Rowland, Ryan C.; Naftz, David L.

2001-01-01

Three permeable reactive barriers (PRBs) were installed near Fry Canyon, Utah, in August 1997 to demonstrate the use of PRBs to control the migration of uranium in ground water. Reactive material included (1) bone-char phosphate, (2) zero-valent iron pellets, and (3) amorphous ferric oxyhydroxide coated gravel. An extensive monitoring network was installed in and around each PRB for collection of water samples, analysis of selected water-quality parameters, and monitoring of water levels. Water temperature, specific conductance, pH, Eh (oxidation-reduction potential), and dissolved oxygen were measured continuously within three different barrier materials, and in two monitoring wells. Water temperature and water level below land surface were electronically recorded every hour with pressure transducers. Data were collected from ground-water monitoring wells installed in and around the PRBs during 1996-98 and from surface-water sites in Fry Creek.

Remote Collaboration on Task Scheduling for Humans at Mars

NASA Technical Reports Server (NTRS)

Jaap, John; Meyer, Patrick; Davis, Elizabeth; Richardson, Lea

2006-01-01

As humans venture farther from Earth for longer durations, it will become essential for those on the journey to have significant control over the scheduling of their own activities as well as the activities of their companion systems and robots. However, the crew will not do all the scheduling; timelines will be the result of collaboration with ground personnel. Emerging technologies such as in-space message buses, delay-tolerant networks, and in-space internet will be the carriers on which the collaboration rides. Advances in scheduling technology, in the areas of task modeling, scheduling engines, and user interfaces will allow the crew to become virtual scheduling experts. New concepts of operations for producing the timeline will allow the crew and the ground support to collaborate while providing safeguards to ensure that the mission will be effectively accomplished without endangering the systems or personnel.

In-Space Crew-Collaborative Task Scheduling

NASA Technical Reports Server (NTRS)

Jaap, John; Meyer, Patrick; Davis, Elizabeth; Richardson, Lea

2006-01-01

As humans venture farther from earth for longer durations, it will become essential for those on the journey to have significant control over the scheduling of their own activities as well as the activities of their companion systems and robots. However, there are many reasons why the crew will not do all the scheduling; timelines will be the result of collaboration with ground personnel. Emerging technologies such as in-space message buses, delay-tolerant networks, and in-space internet will be the carriers on which the collaboration rides. Advances in scheduling technology, in the areas of task modeling, scheduling engines, and user interfaces will allow the crew to become virtual scheduling experts. New concepts of operations for producing the timeline will allow the crew and the ground support to collaborate while providing safeguards to ensure that the mission will be effectively accomplished without endangering the systems or personnel.

Protecting intellectual property in space; Proceedings of the Aerospace Computer Security Conference, McLean, VA, March 20, 1985

NASA Technical Reports Server (NTRS)

1985-01-01

The primary purpose of the Aerospace Computer Security Conference was to bring together people and organizations which have a common interest in protecting intellectual property generated in space. Operational concerns are discussed, taking into account security implications of the space station information system, Space Shuttle security policies and programs, potential uses of probabilistic risk assessment techniques for space station development, key considerations in contingency planning for secure space flight ground control centers, a systematic method for evaluating security requirements compliance, and security engineering of secure ground stations. Subjects related to security technologies are also explored, giving attention to processing requirements of secure C3/I and battle management systems and the development of the Gemini trusted multiple microcomputer base, the Restricted Access Processor system as a security guard designed to protect classified information, and observations on local area network security.

Evaluating the Real-time and Offline Performance of the Virtual Seismologist Earthquake Early Warning Algorithm

NASA Astrophysics Data System (ADS)

Cua, G.; Fischer, M.; Heaton, T.; Wiemer, S.

2009-04-01

The Virtual Seismologist (VS) algorithm is a Bayesian approach to regional, network-based earthquake early warning (EEW). Bayes' theorem as applied in the VS algorithm states that the most probable source estimates at any given time is a combination of contributions from relatively static prior information that does not change over the timescale of earthquake rupture and a likelihood function that evolves with time to take into account incoming pick and amplitude observations from the on-going earthquake. Potentially useful types of prior information include network topology or station health status, regional hazard maps, earthquake forecasts, and the Gutenberg-Richter magnitude-frequency relationship. The VS codes provide magnitude and location estimates once picks are available at 4 stations; these source estimates are subsequently updated each second. The algorithm predicts the geographical distribution of peak ground acceleration and velocity using the estimated magnitude and location and appropriate ground motion prediction equations; the peak ground motion estimates are also updated each second. Implementation of the VS algorithm in California and Switzerland is funded by the Seismic Early Warning for Europe (SAFER) project. The VS method is one of three EEW algorithms whose real-time performance is being evaluated and tested by the California Integrated Seismic Network (CISN) EEW project. A crucial component of operational EEW algorithms is the ability to distinguish between noise and earthquake-related signals in real-time. We discuss various empirical approaches that allow the VS algorithm to operate in the presence of noise. Real-time operation of the VS codes at the Southern California Seismic Network (SCSN) began in July 2008. On average, the VS algorithm provides initial magnitude, location, origin time, and ground motion distribution estimates within 17 seconds of the earthquake origin time. These initial estimate times are dominated by the time for 4 acceptable picks to be available, and thus are heavily influenced by the station density in a given region; these initial estimate times also include the effects of telemetry delay, which ranges between 6 and 15 seconds at the SCSN, and processing time (~1 second). Other relevant performance statistics include: 95% of initial real-time location estimates are within 20 km of the actual epicenter, 97% of initial real-time magnitude estimates are within one magnitude unit of the network magnitude. Extension of real-time VS operations to networks in Northern California is an on-going effort. In Switzerland, the VS codes have been run on offline waveform data from over 125 earthquakes recorded by the Swiss Digital Seismic Network (SDSN) and the Swiss Strong Motion Network (SSMS). We discuss the performance of the VS algorithm on these datasets in terms of magnitude, location, and ground motion estimation.

Decadal-scale changes of pesticides in ground water of the United States, 1993-2003.

PubMed

Bexfield, Laura M

2008-01-01

Pesticide data for ground water sampled across the United States between 1993-1995 and 2001-2003 by the U.S. Geological Survey National Water-Quality Assessment Program were evaluated for trends in detection frequency and concentration. The data analysis evaluated samples collected from a total of 362 wells located in 12 local well networks characterizing shallow ground water in agricultural areas and six local well networks characterizing the drinking water resource in areas of variable land use. Each well network was sampled once during 1993-1995 and once during 2001-2003. The networks provide an overview of conditions across a wide range of hydrogeologic settings and in major agricultural areas that vary in dominant crop type and pesticide use. Of about 80 pesticide compounds analyzed, only six compounds were detected in ground water from at least 10 wells during both sampling events. These compounds were the triazine herbicides atrazine, simazine, and prometon; the acetanilide herbicide metolachlor; the urea herbicide tebuthiuron; and an atrazine degradate, deethylatrazine (DEA). Observed concentrations of these compounds generally were < 0.12 microg L(-1). At individual wells, changes in concentrations typically were < 0.02 microg L(-1). Data analysis incorporated adjustments for changes in laboratory recovery as assessed through laboratory spikes. In wells yielding detectable concentrations of atrazine, DEA, and prometon, concentrations were significantly lower (alpha = 0.1) in 2001-2003 than in 1993-1995, whereas detection frequency of these compounds did not change significantly. Trends in atrazine concentrations at shallow wells in agricultural areas were found to be consistent overall with recent atrazine use data.

Preliminary subsidence investigation of Sacramento Valley, California

USGS Publications Warehouse

Lofgren, B.E.; Ireland, R.L.

1973-01-01

Although a number of agencies have made leveling surveys in Sacramento Valley and a valleywide network of first- and second-order control exists, few areas have sufficient control for determining whether land subsidence has occurred and if so, how much, within the time span of vertical control. Available data suggest that 0.2 to 0.9 foot (0.06 to 0.3 m) of subsidence probably has occurred from 1935-42 to 1964 in an extensive agricultural area of heavy ground-water pumping between Zamora and Davis, and that as much as 2 feet (0.6 m) of subsidence has occurred in at least two areas of pumping overdraft--east of Zamora, and west of Arbuckle. A comparison of maps showing long-term water-level decline and average annual ground-water pumpage indicates several other areas of probable subsidence. In six general areas--northwest of Sacramento; northeast of Sacramento; southeast of Yuba City; 10 miles (16 km) north of Willows; 20 miles (32 km) north of Willows; and especially in the Arbuckle area,ground-water declines have quite probably produced significant subsidence. In two areas of most intensive pumping, no long-term water-level declines have occurred, and no subsidence is indicated. If problems of land subsidence are of concern in Sacramento Valley, and if estimates of historic subsidence or subsidence potential are needed, serious consideration should be given to a field program of basic-data collection. Second-order leveling along a few carefully selected lines of existing control, and the installation and operation of two or three compaction recorders in areas of continuing water-level decline, would provide helpful data for estimating .past and future subsidence.

Trusted Data Communication and Security Issues in Gnss Network of Turkey

NASA Astrophysics Data System (ADS)

Bakici, S.; Erkek, B.; Manti, V.; Altekin, A.

2017-11-01

There are three main activities of General Directorate of Land Registry and Cadastre. These are Mapping, Land Registry and Cadastre. Geomatic Department is responsible for mapping activities. The most important projects like TUSAGA-Aktif (CORS-Tr), Metadata Geoportal, Orthophoto Production and orthophoto web services and preparation of Turkish NSDI Feasibility Report have been conducted and completed by this department's specialists since 2005. TUSAGA-Aktif (CORS-Tr) System, serves location information at cm level accuracy in Turkey and TR Nortern Cyprus in few seconds, where adequate numbers of GNSS satellites are observed and communication possibilities are present. No ground control points and benchmarks are necessary. There are 146 permanent GNSS stations within the CORS-Tr System. Station data are transferred online to the main control center located in the Mapping Department of the General Directorate of Land Registry and Cadastre and to the control center located in the General Command of Mapping. Currently CORS-Tr has more than 9000 users. Most of them are private companies working for governmental organization. Providing data communication between control center and both GNSS station and users via trusted and good substructure is important. Additionally, protection of the system and data against cyber attacks from domestic and foreign sources is important. This paper focuses on data communication and security issues of GNSS network named TUSAGA-Aktif.

30 CFR 77.1004 - Ground control; inspection and maintenance; general.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Ground control; inspection and maintenance... OF UNDERGROUND COAL MINES Ground Control § 77.1004 Ground control; inspection and maintenance... unsafe ground conditions shall be corrected promptly, or the area shall be posted. ...

30 CFR 77.1004 - Ground control; inspection and maintenance; general.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Ground control; inspection and maintenance... OF UNDERGROUND COAL MINES Ground Control § 77.1004 Ground control; inspection and maintenance... unsafe ground conditions shall be corrected promptly, or the area shall be posted. ...

The 13 th Annual Intelligent Ground Vehicle Competition: intelligent ground vehicles created by intelligent teams

NASA Astrophysics Data System (ADS)

Theisen, Bernard L.

2005-10-01

The Intelligent Ground Vehicle Competition (IGVC) is one of three, unmanned systems, student competitions that were founded by the Association for Unmanned Vehicle Systems International (AUVSI) in the 1990s. The IGVC is a multidisciplinary exercise in product realization that challenges college engineering student teams to integrate advanced control theory, machine vision, vehicular electronics, and mobile platform fundamentals to design and build an unmanned system. Teams from around the world focus on developing a suite of dual-use technologies to equip ground vehicles of the future with intelligent driving capabilities. Over the past 13 years, the competition has challenged undergraduate, graduate and Ph.D. students with real world applications in intelligent transportation systems, the military and manufacturing automation. To date, teams from over 50 universities and colleges have participated. This paper describes some of the applications of the technologies required by this competition and discusses the educational benefits. The primary goal of the IGVC is to advance engineering education in intelligent vehicles and related technologies. The employment and professional networking opportunities created for students and industrial sponsors through a series of technical events over the three-day competition are highlighted. Finally, an assessment of the competition based on participant feedback is presented.

The link evaluation terminal for the advanced communications technology satellite experiments program

NASA Technical Reports Server (NTRS)

May, Brian D.

1992-01-01

The experimental NASA satellite, Advanced Communications Technology Satellite (ACTS), introduces new technology for high throughput 30 to 20 GHz satellite services. Contained in a single communication payload is both a regenerative TDMA system and multiple 800 MHz 'bent pipe' channels routed to spot beams by a switch matrix. While only one mode of operation is typical during any experiment, both modes can operate simultaneously with reduced capability due to sharing of the transponder. NASA-Lewis instituted a ground terminal development program in anticipation of the satellite launch to verify the performance of the switch matrix mode of operations. Specific functions are built into the ground terminal to evaluate rain fade compensation with uplink power control and to monitor satellite transponder performance with bit error rate measurements. These functions were the genesis of the ground terminal's name, Link Evaluation Terminal, often referred to as LET. Connectors are included in LET that allow independent experimenters to run unique modulation or network experiments through ACTS using only the RF transmit and receive portions of LET. Test data indicate that LET will be able to verify important parts of ACTS technology and provide independent experimenters with a useful ground terminal. Lab measurements of major subsystems integrated into LET are presented. Bit error rate is measured with LET in an internal loopback mode.

Fully automated, real-time 3D ultrasound segmentation to estimate first trimester placental volume using deep learning.

PubMed

Looney, Pádraig; Stevenson, Gordon N; Nicolaides, Kypros H; Plasencia, Walter; Molloholli, Malid; Natsis, Stavros; Collins, Sally L

2018-06-07

We present a new technique to fully automate the segmentation of an organ from 3D ultrasound (3D-US) volumes, using the placenta as the target organ. Image analysis tools to estimate organ volume do exist but are too time consuming and operator dependant. Fully automating the segmentation process would potentially allow the use of placental volume to screen for increased risk of pregnancy complications. The placenta was segmented from 2,393 first trimester 3D-US volumes using a semiautomated technique. This was quality controlled by three operators to produce the "ground-truth" data set. A fully convolutional neural network (OxNNet) was trained using this ground-truth data set to automatically segment the placenta. OxNNet delivered state-of-the-art automatic segmentation. The effect of training set size on the performance of OxNNet demonstrated the need for large data sets. The clinical utility of placental volume was tested by looking at predictions of small-for-gestational-age babies at term. The receiver-operating characteristics curves demonstrated almost identical results between OxNNet and the ground-truth). Our results demonstrated good similarity to the ground-truth and almost identical clinical results for the prediction of SGA.

Network modules and hubs in plant-root fungal biomes

PubMed Central

Toju, Hirokazu; Yamamoto, Satoshi; Tanabe, Akifumi S.; Hayakawa, Takashi; Ishii, Hiroshi S.

2016-01-01

Terrestrial plants host phylogenetically and functionally diverse groups of below-ground microbes, whose community structure controls plant growth/survival in both natural and agricultural ecosystems. Therefore, understanding the processes by which whole root-associated microbiomes are organized is one of the major challenges in ecology and plant science. We here report that diverse root-associated fungi can form highly compartmentalized networks of coexistence within host roots and that the structure of the fungal symbiont communities can be partitioned into semi-discrete types even within a single host plant population. Illumina sequencing of root-associated fungi in a monodominant south beech forest revealed that the network representing symbiont–symbiont co-occurrence patterns was compartmentalized into clear modules, which consisted of diverse functional groups of mycorrhizal and endophytic fungi. Consequently, terminal roots of the plant were colonized by either of the two largest fungal species sets (represented by Oidiodendron or Cenococcum). Thus, species-rich root microbiomes can have alternative community structures, as recently shown in the relationships between human gut microbiome type (i.e. ‘enterotype’) and host individual health. This study also shows an analytical framework for pinpointing network hubs in symbiont–symbiont networks, leading to the working hypothesis that a small number of microbial species organize the overall root–microbiome dynamics. PMID:26962029

Ground-water-quality assessment of the Central Oklahoma aquifer, Oklahoma; hydrologic, water-quality, and quality-assurance data 1987-90

USGS Publications Warehouse

Ferree, D.M.; Christenson, S.C.; Rea, A.H.; Mesander, B.A.

1992-01-01

This report presents data collected from 202 wells between June 1987 and September 1990 as part of the Central Oklahoma aquifer pilot study of the National Water-Quality Assessment Program. The report describes the sampling networks, the sampling procedures, and the results of the ground-water quality and quality-assurance sample analyses. The data tables consist of information about the wells sampled and the results of the chemical analyses of ground water and quality-assurance sampling. Chemical analyses of ground-water samples in four sampling networks are presented: A geochemical network, a low-density survey bedrock network, a low-density survey alluvium and terrace deposits network, and a targeted urban network. The analyses generally included physical properties, major ions, nutrients, trace substances, radionuclides, and organic constituents. The chemical analyses of the ground-water samples are presented in five tables: (1) Physical properties and concentrations of major ions, nutrients, and trace substances; (2) concentrations of radionuclides and radioactivities; (3) carbon isotope ratios and delta values (d-values) of selected isotopes; (4) concentrations of organic constituents; and (5) organic constituents not reported in ground-water samples. The quality of the ground water sampled varied substantially. The sum of constituents (dissolved solids) concentrations ranged from 71 to 5,610 milligrams per liter, with 38 percent of the wells sampled exceeding the Secondary Maximum Contaminant Level of 500 milligrams per liter established under the Safe Drinking Water Act. Values of pH ranged from 5.7 to 9.2 units with 20 percent of the wells outside the Secondary Maximum Contaminant Level of 6.5 to 8.5 units. Nitrite plus nitrate concentrations ranged from less than 0.1 to 85 milligrams per liter with 8 percent of the wells exceeding the proposed Maximum Contaminant Level of 10 milligrams per liter. Concentrations of trace substances were highly variable, ranging from below the reporting level to concentrations over the Maximum Contaminant Levels for several constituents (arsenic, barium, cadmium, chromium, lead, and selenium). Radionuclide activities also were highly variable. Gross alpha radioactivity ranged from 0.1 to 210 picocuries per liter as 230thorium. Of the wells sampled, 20 percent exceeded the proposed Maximum Contaminant Level of 15 picocuries per liter for gross alpha radioactivity. Organic constituents were detected in 39 percent of the 170 wells sampled for organic constituents; in most cases concentrations were at or near the laboratory minimum reporting levels. Ten of the wells sampled for organic constituents had one or more constituents (chlordane, dieldrin, heptachlor epoxide, trichloroethylene, 1,1-dichloroethylene, 1,1,1-trichloroethane) at concentrations equal to or greater than the Maximum Contaminant Level or acceptable concentrations as suggested in the Environmental Protection Agency's Health Advisory Summaries. Quality-assurance sampling included duplicate samples, repeated samples, blanks, spikes, and blind samples. These samples proved to be essential in evaluating the accuracy of the data, particularly in the case of volatile organic constituents.

Introductions to Mission Operations and Ground Data Systems

NASA Technical Reports Server (NTRS)

Stewart, Helen J.

2009-01-01

This slide presentation discusses how in the early concept studies the communications architecture plays an important part: The communications architecture is the arrangement, or configuration of satellites and ground systems in a space system, and the network of communications links that transfers information between them.

Ground-water levels in Wyoming, 1975

USGS Publications Warehouse

Ballance, Wilbur C.; Freudenthal, Pamela B.

1976-01-01

Ground-water levels are measured periodically in a network of about 260 observation wells in Wyoming to record changes in ground-water storage. The areas of water-level observation are mostly where ground water is used in large quantities for irrigation or municipal purposes. This report contains maps showing location of observation wells and water-level changes from 1975 to 1976. Well history, highest and lowest water levels , and hydrographs for most wells also are included in this report.The program of ground-water observation is conducted by the U.S. Geological Survey in cooperation with the Wyoming State Engineer and the city of Cheyenne.

Network Operations Support Plan for the Spot 2 mission (revision 1)

NASA Technical Reports Server (NTRS)

Werbitzky, Victor

1989-01-01

The purpose of this Network Operations Support Plan (NOSP) is to indicate operational procedures and ground equipment configurations for the SPOT 2 mission. The provisions in this document take precedence over procedures or configurations in other documents.

Odor source identification by grounding linguistic descriptions in an artificial nose

NASA Astrophysics Data System (ADS)

Loutfi, Amy; Coradeschi, Silvia; Duckett, Tom; Wide, Peter

2001-03-01

This paper addresses the problem of enabling autonomous agents (e.g., robots) to carry out human oriented tasks using an electronic nose. The nose consists of a combination of passive gas sensors with different selectivity, the outputs of which are fused together with an artificial neural network in order to recognize various human-determined odors. The basic idea is to ground human-provided linguistic descriptions of these odors in the actual sensory perceptions of the nose through a process of supervised learning. Analogous to the human nose, the paper explains a method by which an electronic nose can be used for substance identification. First, the receptors of the nose are exposed to a substance by means of inhalation with an electric pump. Then a chemical reaction takes place in the gas sensors over a period of time and an artificial neural network processes the resulting sensor patterns. This network was trained to recognize a basic set of pure substances such as vanilla, lavender and yogurt under controlled laboratory conditions. The complete system was then validated through a series of experiments on various combinations of the basic substances. First, we showed that the nose was able to consistently recognize unseen samples of the same substances on which it had been trained. In addition, we presented some first results where the nose was tested on novel combinations of substances on which it had not been trained by combining the learned descriptions - for example, it could distinguish lavender yogurt as a combination of lavender and yogurt.