The U.S. Geological Survey Modular Ground-Water Model - PCGN: A Preconditioned Conjugate Gradient Solver with Improved Nonlinear Control

USGS Publications Warehouse

Naff, Richard L.; Banta, Edward R.

2008-01-01

The preconditioned conjugate gradient with improved nonlinear control (PCGN) package provides addi-tional means by which the solution of nonlinear ground-water flow problems can be controlled as compared to existing solver packages for MODFLOW. Picard iteration is used to solve nonlinear ground-water flow equations by iteratively solving a linear approximation of the nonlinear equations. The linear solution is provided by means of the preconditioned conjugate gradient algorithm where preconditioning is provided by the modi-fied incomplete Cholesky algorithm. The incomplete Cholesky scheme incorporates two levels of fill, 0 and 1, in which the pivots can be modified so that the row sums of the preconditioning matrix and the original matrix are approximately equal. A relaxation factor is used to implement the modified pivots, which determines the degree of modification allowed. The effects of fill level and degree of pivot modification are briefly explored by means of a synthetic, heterogeneous finite-difference matrix; results are reported in the final section of this report. The preconditioned conjugate gradient method is coupled with Picard iteration so as to efficiently solve the nonlinear equations associated with many ground-water flow problems. The description of this coupling of the linear solver with Picard iteration is a primary concern of this document.

Use of synthetic ground covers to control weeds in blackberries

USDA-ARS?s Scientific Manuscript database

Weed control in blackberries (Rubus spp.) is a serious problem for organic producers and those who wish to reduce their reliance on herbicides. Three landscape fabrics (Dewitt, Texel, and a white polyester weave) and one industrial grade white on black plastic were used for weed control in conjucti...

Identification and stochastic control of helicopter dynamic modes

NASA Technical Reports Server (NTRS)

Molusis, J. A.; Bar-Shalom, Y.

1983-01-01

A general treatment of parameter identification and stochastic control for use on helicopter dynamic systems is presented. Rotor dynamic models, including specific applications to rotor blade flapping and the helicopter ground resonance problem are emphasized. Dynamic systems which are governed by periodic coefficients as well as constant coefficient models are addressed. The dynamic systems are modeled by linear state variable equations which are used in the identification and stochastic control formulation. The pure identification problem as well as the stochastic control problem which includes combined identification and control for dynamic systems is addressed. The stochastic control problem includes the effect of parameter uncertainty on the solution and the concept of learning and how this is affected by the control's duel effect. The identification formulation requires algorithms suitable for on line use and thus recursive identification algorithms are considered. The applications presented use the recursive extended kalman filter for parameter identification which has excellent convergence for systems without process noise.

Quality-control results for ground-water and surface-water data, Sacramento River Basin, California, National Water-Quality Assessment, 1996-1998

USGS Publications Warehouse

Munday, Cathy; Domagalski, Joseph L.

2003-01-01

Evaluating the extent that bias and variability affect the interpretation of ground- and surface-water data is necessary to meet the objectives of the National Water-Quality Assessment (NAWQA) Program. Quality-control samples used to evaluate the bias and variability include annual equipment blanks, field blanks, field matrix spikes, surrogates, and replicates. This report contains quality-control results for the constituents critical to the ground- and surface-water components of the Sacramento River Basin study unit of the NAWQA Program. A critical constituent is one that was detected frequently (more than 50 percent of the time in blank samples), was detected at amounts exceeding water-quality standards or goals, or was important for the interpretation of water-quality data. Quality-control samples were collected along with ground- and surface-water samples during the high intensity phase (cycle 1) of the Sacramento River Basin NAWQA beginning early in 1996 and ending in 1998. Ground-water field blanks indicated contamination of varying levels of significance when compared with concentrations detected in environmental ground-water samples for ammonia, dissolved organic carbon, aluminum, and copper. Concentrations of aluminum in surface-water field blanks were significant when compared with environmental samples. Field blank samples collected for pesticide and volatile organic compound analyses revealed no contamination in either ground- or surface-water samples that would effect the interpretation of environmental data, with the possible exception of the volatile organic compound trichloromethane (chloroform) in ground water. Replicate samples for ground water and surface water indicate that variability resulting from sample collection, processing, and analysis was generally low. Some of the larger maximum relative percentage differences calculated for replicate samples occurred between samples having lowest absolute concentration differences and(or) values near the reporting limit. Surrogate recoveries for pesticides analyzed by gas chromatography/mass spectrometry (GC/MS), pesticides analyzed by high performance liquid chromatography (HPLC), and volatile organic compounds in ground- and surface-water samples were within the acceptable limits of 70 to 130 percent and median recovery values between 82 and 113 percent. The recovery percentages for surrogate compounds analyzed by HPLC had the highest standard deviation, 20 percent for ground-water samples and 16 percent for surface-water samples, and the lowest median values, 82 percent for ground-water samples and 91 percent for surface-water samples. Results were consistent with the recovery results described for the analytical methods. Field matrix spike recoveries for pesticide compounds analyzed using GC/MS in ground- and surface-water samples were comparable with published recovery data. Recoveries of carbofuran, a critical constituent in ground- and surface-water studies, and desethyl atrazine, a critical constituent in the ground-water study, could not be calculated because of problems with the analytical method. Recoveries of pesticides analyzed using HPLC in ground- and surface-water samples were generally low and comparable with published recovery data. Other methodological problems for HPLC analytes included nondetection of the spike compounds and estimated values of spike concentrations. Recovery of field matrix spikes for volatile organic compounds generally were within the acceptable range, 70 and 130 percent for both ground- and surface-water samples, and median recoveries from 62 to 127 percent. High or low recoveries could be related to errors in the field, such as double spiking or using spike solution past its expiration date, rather than problems during analysis. The methodological changes in the field spike protocol during the course of the Sacramento River Basin study, which included decreasing the amount of spike solu

Eccentricity and argument of perigee control for orbits with repeat ground tracks

NASA Technical Reports Server (NTRS)

Vincent, Mark A.

1992-01-01

In order to gain an understanding into the problem of eccentricity (e) and argument of perigee (omega) control for TOPEX/Poseidon, the two cases where the highest latitude crossing time and one of the equator crossings are held constant are investigated. Variations in e and omega cause a significant effect on the satellite's ground-track repeatability. Maintaining e and omega near their frozen values will minimize this variation. Analytical expressions are found to express this relationship while keeping an arbitrary point of the ground track fixed. The initial offset of the ground track from its nominal path determines the subsequent evolution of e and omega about their frozen values. This long-term behavior is numerically determined using an earth gravitational field including the first 17 zonal harmonics. The numerical results are plotted together with the analytical constraints to see if the later values of e and omega cause unacceptable deviation in the ground track.

Newer Technologies for School Security. ERIC Digest Number 145.

ERIC Educational Resources Information Center

Schneider, Tod

This digest describes several technologies that can be used to control access to, and improve surveillance of, school grounds. Access can be controlled by using "smart" cards to control keyed entries. Many schools have problems with multiple copies of keys, and these card systems are integrated with computer software that allows for…

Results of the recent precipitation static flight test program on the Navy P-3B antisubmarine aircraft

NASA Technical Reports Server (NTRS)

Whitaker, Mike

1991-01-01

Severe precipitation static problems affecting the communication equipment onboard the P-3B aircraft were recently studied. The study was conducted after precipitation static created potential safety-of-flight problems on Naval Reserve aircraft. A specially designed flight test program was conducted in order to measure, record, analyze, and characterize potential precipitation static problem areas. The test program successfully characterized the precipitation static interference problems while the P-3B was flown in moderate to extreme precipitation conditions. Data up to 400 MHz were collected on the effects of engine charging, precipitation static, and extreme cross fields. These data were collected using a computer controlled acquisition system consisting of a signal generator, RF spectrum and audio analyzers, data recorders, and instrumented static dischargers. The test program is outlined and the computer controlled data acquisition system is described in detail which was used during flight and ground testing. The correlation of test results is also discussed which were recorded during the flight test program and those measured during ground testing.

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.

Automatic Scheduling and Planning (ASAP) in future ground control systems

NASA Technical Reports Server (NTRS)

Matlin, Sam

1988-01-01

This report describes two complementary approaches to the problem of space mission planning and scheduling. The first is an Expert System or Knowledge-Based System for automatically resolving most of the activity conflicts in a candidate plan. The second is an Interactive Graphics Decision Aid to assist the operator in manually resolving the residual conflicts which are beyond the scope of the Expert System. The two system designs are consistent with future ground control station activity requirements, support activity timing constraints, resource limits and activity priority guidelines.

Smoke Management: Toward a Data Base to Validate PB-Piedmont - Numerical Simulation of Smoke on the Ground at Night

Treesearch

Gary L. Achtemeier

1999-01-01

The use of fire for controlled burning to meet objectives for silviculture or for ecosystem management carries the risk of liability for smoke. Near-ground smoke can degrade air quality, reduce visibility, aggravate health problems, and create a general nuisance. At night, smoke can locally limit visibility over roadways creating serious hazards to transportation. PB-...

Calibrating and adjusting expectations in life: A grounded theory on how elderly persons with somatic health problems maintain control and balance in life and optimize well-being

PubMed Central

Helvik, Anne-Sofie; Iversen, Valentina Cabral; Steiring, Randi; Hallberg, Lillemor R-M

2011-01-01

Aim This study aims at exploring the main concern for elderly individuals with somatic health problems and what they do to manage this. Method In total, 14 individuals (mean=74.2 years; range=68–86 years) of both gender including hospitalized and outpatient persons participated in the study. Open interviews were conducted and analyzed according to grounded theory, an inductive theory-generating method. Results The main concern for the elderly individuals with somatic health problems was identified as their striving to maintain control and balance in life. The analysis ended up in a substantive theory explaining how elderly individuals with somatic disease were calibrating and adjusting their expectations in life in order to adapt to their reduced energy level, health problems, and aging. By adjusting the expectations to their actual abilities, the elderly can maintain a sense of that they still have the control over their lives and create stability. The ongoing adjustment process is facilitated by different strategies and result despite lower expectations in subjective well-being. The facilitating strategies are utilizing the network of important others, enjoying cultural heritage, being occupied with interests, having a mission to fulfill, improving the situation by limiting boundaries and, finally, creating meaning in everyday life. Conclusion The main concern of the elderly with somatic health problems was to maintain control and balance in life. The emerging theory explains how elderly people with somatic health problems calibrate their expectations of life in order to adjust to reduced energy, health problems, and aging. This process is facilitated by different strategies and result despite lower expectation in subjective well-being. PMID:21468299

Application of spring tabs to elevator controls

NASA Technical Reports Server (NTRS)

Phillips, William H

1944-01-01

Equations are presented for calculating the stick-force characteristics obtained with a spring-tab type of elevator control. The main problems encountered in the design of a satisfactory elevator spring tab are to provide stick forces in the desired range, to maintain the force per g sufficiently constant throughout the speed range, to avoid undesirable "feel" of the control in ground handling or in flight at low airspeeds, and to prevent flutter. Examples are presented to show the design features of spring tabs required to solve these problems for airplanes of various sizes.

Action-based language: a theory of language acquisition, comprehension, and production.

PubMed

Glenberg, Arthur M; Gallese, Vittorio

2012-07-01

Evolution and the brain have done a marvelous job solving many tricky problems in action control, including problems of learning, hierarchical control over serial behavior, continuous recalibration, and fluency in the face of slow feedback. Given that evolution tends to be conservative, it should not be surprising that these solutions are exploited to solve other tricky problems, such as the design of a communication system. We propose that a mechanism of motor control, paired controller/predictor models, has been exploited for language learning, comprehension, and production. Our account addresses the development of grammatical regularities and perspective, as well as how linguistic symbols become meaningful through grounding in perception, action, and emotional systems. Copyright © 2011 Elsevier Srl. All rights reserved.

Tecnologias mas nuevas para la seguridad escolar (Newer Technologies for School Security). ERIC Digest.

ERIC Educational Resources Information Center

Schneider, Tod

This digest in Spanish describes several technologies that can be used to control access to, and improve surveillance of, school grounds. Access can be controlled by using "smart" cards to control keyed entries. Many schools have problems with multiple copies of keys, and these card systems are integrated with computer software that…

A method of measuring increase in soil depth and water-storage capacity due to forest management

Treesearch

George R., Jr. Trimble

1952-01-01

Conservationists, engineers, and others who deal with water problems have become more and more concerned in recent years with increasing the storage of water in the ground. Their concern has centered around problems of flood control and storage of water for later use by plants or animals, including man.

Control Engineering, System Theory and Mathematics: The Teacher's Challenge

ERIC Educational Resources Information Center

Zenger, K.

2007-01-01

The principles, difficulties and challenges in control education are discussed and compared to the similar problems in the teaching of mathematics and systems science in general. The difficulties of today's students to appreciate the classical teaching of engineering disciplines, which are based on rigorous and scientifically sound grounds, are…

Ergonomic problems regarding the interactive touch input via screens in onboard and ground-based flight control

NASA Technical Reports Server (NTRS)

Holzhausen, K. P.; Gaertner, K. P.

1985-01-01

A significant problem concerning the integration of display and switching functions is related to the fact that numerous informative data which have to be processed by man must be read from only a few display devices. A satisfactory ergonomic design of integrated display devices and keyboards is in many cases difficult, because not all functions which can be displayed and selected are simultaneously available. A technical solution which provides an integration of display and functional elements on the basis of the highest flexibility is obtained by using a cathode ray tube with a touch-sensitive screen. The employment of an integrated data input/output system is demonstrated for the cases of onboard and ground-based flight control. Ergonomic studies conducted to investigate the suitability of an employment of touch-sensitive screens are also discussed.

Astronaut Richard Truly seen working with Apollo docking mechanism model

NASA Technical Reports Server (NTRS)

1975-01-01

Astronaut Richard H. Truly, an Apollo Soyuz Test Project (ASTP) spacecraft communicator, is seen working with an Apollo docking mechanism in the Mission Control Center during the joint U.S.-USSR ASTP docking in Earth orbit mission. Astronaut Truly, a member of the American ASTP crew support team, was working on the docking probe problem. The crew had notified ground control that there was a problem with removing the probe from the tunnel of the Apollo Command Module.

Controlled Ecological Life Support System. Design, Development, and Use of a Ground-Based Plant Growth Module

NASA Technical Reports Server (NTRS)

Macelroy, Robert D.; Smernoff, David T.; Rummel, John D.

1987-01-01

Problems of food production by higher plants are addressed. Experimentation requirements and necessary equipment for designing an experimental Controlled Ecological Life Support System (CELSS) Plant Growth Module are defined. A framework is provided for the design of laboratory sized plant growth chambers. The rationale for the development of an informal collaborative effort between investigators from universities and industry and those at Ames is evaluated. Specific research problems appropriate for collaborative efforts are identified.

[Ground-clearing fires in the amazon and respiratory disease].

PubMed

Gonçalves, Karen dos Santos; de Castro, Hermano Albuquerque; Hacon, Sandra de Souza

2012-06-01

The intentional burning of forest biomass commonly known as "ground-clearing fires" is an age-old and widespread practice in the country and is seen as a major contributor to global emissions of greenhouse gases. However, global awareness of their potential impact is relatively recent. The occurrence of large ground-clearing fires in the Brazilian and international scenarios drew attention to the problem, but the measures taken to prevent and/or control the fires are still insufficient. In the Amazon region, with distinct geographical and environmental features from the rest of the country, with its historic process of land occupation, every year the ground-clearing fires expose larger portions of the population making them vulnerable to its effects. In this context, this non-systematic review presents the papers written over the past five years about the fires in the Brazilian Amazon and respiratory illness. The main objective is to provide information for managers and leaders on environmental issues about the problems related to biomass burning in the Amazon region.

Lifelong Transfer Learning for Heterogeneous Teams of Agents in Sequential Decision Processes

DTIC Science & Technology

2016-06-01

making (SDM) tasks in dynamic environments with simulated and physical robots . 15. SUBJECT TERMS Sequential decision making, lifelong learning, transfer...sequential decision-making (SDM) tasks in dynamic environments with both simple benchmark tasks and more complex aerial and ground robot tasks. Our work...and ground robots in the presence of disturbances: We applied our methods to the problem of learning controllers for robots with novel disturbances in

Detecting Target Objects by Natural Language Instructions Using an RGB-D Camera

PubMed Central

Bao, Jiatong; Jia, Yunyi; Cheng, Yu; Tang, Hongru; Xi, Ning

2016-01-01

Controlling robots by natural language (NL) is increasingly attracting attention for its versatility, convenience and no need of extensive training for users. Grounding is a crucial challenge of this problem to enable robots to understand NL instructions from humans. This paper mainly explores the object grounding problem and concretely studies how to detect target objects by the NL instructions using an RGB-D camera in robotic manipulation applications. In particular, a simple yet robust vision algorithm is applied to segment objects of interest. With the metric information of all segmented objects, the object attributes and relations between objects are further extracted. The NL instructions that incorporate multiple cues for object specifications are parsed into domain-specific annotations. The annotations from NL and extracted information from the RGB-D camera are matched in a computational state estimation framework to search all possible object grounding states. The final grounding is accomplished by selecting the states which have the maximum probabilities. An RGB-D scene dataset associated with different groups of NL instructions based on different cognition levels of the robot are collected. Quantitative evaluations on the dataset illustrate the advantages of the proposed method. The experiments of NL controlled object manipulation and NL-based task programming using a mobile manipulator show its effectiveness and practicability in robotic applications. PMID:27983604

Shuttle Orbiter Active Thermal Control Subsystem design and flight experience

NASA Technical Reports Server (NTRS)

Bond, Timothy A.; Metcalf, Jordan L.; Asuncion, Carmelo

1991-01-01

The paper examines the design of the Space Shuttle Orbiter Active Thermal Control Subsystem (ATCS) constructed for providing the vehicle and payload cooling during all phases of a mission and during ground turnaround operations. The operation of the Shuttle ATCS and some of the problems encountered during the first 39 flights of the Shuttle program are described, with special attention given to the major problems encountered with the degradation of the Freon flow rate on the Orbiter Columbia, the Flash Evaporator Subsystem mission anomalies which occurred on STS-26 and STS-34, and problems encountered with the Ammonia Boiler Subsystem. The causes and the resolutions of these problems are discussed.

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.

Quality Improvement of Ground Works Process with the Use of Chosen Lean Management Tools - Case Study

NASA Astrophysics Data System (ADS)

Nowotarski, Piotr; Paslawski, Jerzy; Wysocki, Bartosz

2017-12-01

Ground works are one of the first processes connected with erecting structures. Based on ground conditions like the type of soil or level of underground water different types and solutions for foundations are designed. Foundations are the base for the buildings, and their proper design and execution is the key for the long and faultless use of the whole construction and might influence on the future costs of the eventual repairs (especially when ground water level is high, and there is no proper water insulation made). Article presents the introduction of chosen Lean Management tools for quality improvement of the process of ground works based on the analysis made on the construction site of vehicle control station located in Poznan, Poland. Processes assessment is made from different perspectives taking into account that 3 main groups of workers were directly involved in the process: blue collar-workers, site manager and site engineers. What is more comparison is made on the 3 points of view to the problems that might occur during this type of works, with details analysis on the causes of such situation? Authors presents also the change of approach of workers directly involved in the mentioned processes regarding introduction of Lean Management methodology, which illustrates the problem of scepticism for new ideas of the people used to perform works and actions in traditional way. Using Lean Management philosophy in construction is a good idea to streamline processes in company, get rid of constantly recurring problems, and in this way improve the productivity and quality of executed activities. Performed analysis showed that different groups of people have very different idea and opinion on the problems connected with executing the same process - ground works and only having full picture of the situation (especially in construction processes) management can take proper problems-preventing actions that consequently can influence on the amount of waste generated on the construction cite which positively influence on the external environment.

Powered ankle-foot prosthesis to assist level-ground and stair-descent gaits.

PubMed

Au, Samuel; Berniker, Max; Herr, Hugh

2008-05-01

The human ankle varies impedance and delivers net positive work during the stance period of walking. In contrast, commercially available ankle-foot prostheses are passive during stance, causing many clinical problems for transtibial amputees, including non-symmetric gait patterns, higher gait metabolism, and poorer shock absorption. In this investigation, we develop and evaluate a myoelectric-driven, finite state controller for a powered ankle-foot prosthesis that modulates both impedance and power output during stance. The system employs both sensory inputs measured local to the external prosthesis, and myoelectric inputs measured from residual limb muscles. Using local prosthetic sensing, we first develop two finite state controllers to produce biomimetic movement patterns for level-ground and stair-descent gaits. We then employ myoelectric signals as control commands to manage the transition between these finite state controllers. To transition from level-ground to stairs, the amputee flexes the gastrocnemius muscle, triggering the prosthetic ankle to plantar flex at terminal swing, and initiating the stair-descent state machine algorithm. To transition back to level-ground walking, the amputee flexes the tibialis anterior muscle, triggering the ankle to remain dorsiflexed at terminal swing, and initiating the level-ground state machine algorithm. As a preliminary evaluation of clinical efficacy, we test the device on a transtibial amputee with both the proposed controller and a conventional passive-elastic control. We find that the amputee can robustly transition between the finite state controllers through direct muscle activation, allowing rapid transitioning from level-ground to stair walking patterns. Additionally, we find that the proposed finite state controllers result in a more biomimetic ankle response, producing net propulsive work during level-ground walking and greater shock absorption during stair descent. The results of this study highlight the potential of prosthetic leg controllers that exploit neural signals to trigger terrain-appropriate, local prosthetic leg behaviors.

Feedback from video for virtual reality Navigation

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

Tsap, L V

2000-10-27

Important preconditions for wide acceptance of virtual reality (VR) systems include their comfort, ease and naturalness to use. Most existing trackers super from discomfort-related issues. For example, body-based trackers (hand controllers, joysticks, helmet attachments, etc.) restrict spontaneity and naturalness of motion, while ground-based devices (e.g., hand controllers) limit the workspace by literally binding an operator to the ground. There are similar problems with controls. This paper describes using real-time video with registered depth information (from a commercially available camera) for virtual reality navigation. Camera-based setup can replace cumbersome trackers. The method includes selective depth processing for increased speed, and amore » robust skin-color segmentation for accounting illumination variations.« less

GPS: Actions Needed to Address Ground System Development Problems and User Equipment Production Readiness

DTIC Science & Technology

2015-09-01

Executive Action 43 Agency Comments and Our Evaluation 44 Appendix I Objectives , Scope, and Methodology 47 Appendix II Comments from the Department of...findings and conclusions based on our audit objectives . We believe that the evidence obtained provides a reasonable basis for our findings and...conclusions based on our audit objectives . GPS is a global positioning, navigation, and timing system consisting of space, ground control, and user equipment

Shared control on lunar spacecraft teleoperation rendezvous operations with large time delay

NASA Astrophysics Data System (ADS)

Ya-kun, Zhang; Hai-yang, Li; Rui-xue, Huang; Jiang-hui, Liu

2017-08-01

Teleoperation could be used in space on-orbit serving missions, such as object deorbits, spacecraft approaches, and automatic rendezvous and docking back-up systems. Teleoperation rendezvous and docking in lunar orbit may encounter bottlenecks for the inherent time delay in the communication link and the limited measurement accuracy of sensors. Moreover, human intervention is unsuitable in view of the partial communication coverage problem. To solve these problems, a shared control strategy for teleoperation rendezvous and docking is detailed. The control authority in lunar orbital maneuvers that involves two spacecraft as rendezvous and docking in the final phase was discussed in this paper. The predictive display model based on the relative dynamic equations is established to overcome the influence of the large time delay in communication link. We discuss and attempt to prove via consistent, ground-based simulations the relative merits of fully autonomous control mode (i.e., onboard computer-based), fully manual control (i.e., human-driven at the ground station) and shared control mode. The simulation experiments were conducted on the nine-degrees-of-freedom teleoperation rendezvous and docking simulation platform. Simulation results indicated that the shared control methods can overcome the influence of time delay effects. In addition, the docking success probability of shared control method was enhanced compared with automatic and manual modes.

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.

Water and wastewater related issues in Sri Lanka.

PubMed

Bandara, N J G J

2003-01-01

The primary problems concerning water resources in Sri Lanka are the depletion and degradation of the resource caused by various anthropogenic activities. Surface inland waters in urban areas are polluted heavily with domestic sewage and industrial effluents, and in rural areas with agricultural runoff. With regard to ground water in certain areas of the dry zone, there is a high fluoride content and in hard, rocky, alluvial areas, there is a high concentration of iron. In urban over-crowded cities, there is biological contamination of ground water. Over-utilization, particularly through tube wells, is another major problem affecting ground water resources in Sri Lanka. Oil spills, dumping of waste from ships, coral and sand mining, and activities are the main causes of marine pollution in the country. Except for pipe-borne water supply, irrigation and hydropower schemes, in general water resources in Sri Lanka are managed very poorly. Regulations are available to control most water related problems but enforcement of these regulations is lacking. The ultimate result of degradation and depletion of water resources is the increasing health hazards. Water-borne and vector-borne diseases are prevalent, particularly amongst urban low-income communities with poor sanitary facilities and drainage. Despite government initiatives and legislation, very slow progress has been made towards combating water pollution. This paper examines the most significant water and wastewater related issues in Sri Lanka and their controlling mechanisms.

Reliable transfer of data from ground to space

NASA Technical Reports Server (NTRS)

Brosi, Fred

1993-01-01

This paper describes the problems involved in uplink of data from control centers on the ground to spacecraft, and explores the solutions to those problems, past. present. and future. The evolution of this process, from simple commanding to transfer of large volumes of data and commands is traced. The need for reliable end-to-end protocols for commanding and file transfer is demonstrated, and the shortcomings of both existing telecommand protocols and commercial products to meet this need are discussed. Recent developments in commercial protocols that may be adaptable to the mentioned operations environment are surveyed, and current efforts to develop a suite of protocols for reliable transfer in this environment are presented.

Robust Stability and Control of Multi-Body Ground Vehicles with Uncertain Dynamics and Failures

DTIC Science & Technology

2010-01-01

and N. Zhang, 2008. “Robust stability control of vehicle rollover subject to actuator time delay”. Proc. IMechE Part I: J. of systems and control ...Dynamic Systems and Control Conference, Boston, MA, Sept 2010 R.K. Yedavalli,”Robust Stability of Linear Interval Parameter Matrix Family Problem...for control coupled output regulation for a class of systems is presented. In section 2.1.7, the control design algorithm developed in section

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

Pollution of ground water in Europe

PubMed Central

Buchan, S.; Key, A.

1956-01-01

This paper discusses pollution of ground water in 20 countries of the European region, giving for each an account of the geology and hydrogeology, water supplies, the extent and nature of ground water pollution, and the legal, administrative, and technical means of controlling that pollution. For the countries not considered in the preceding article on surface water pollution, an account is also given of the superficial physical features, rainfall, population, and industries. A general discussion follows of such questions as the ways in which ground water pollution may occur, the factors mitigating or aggravating pollution, and ways of protection against pollution. The authors consider that the problem of ground water pollution in Europe may well be more serious than it would appear to be on the evidence so far obtained. PMID:13374533

Grounding line dynamics inferred from a 3D full-Stokes model solving the contact problem

NASA Astrophysics Data System (ADS)

Favier, Lionel; Gagliardini, Olivier; Durand, Gael; Zwinger, Thomas

2010-05-01

The mass balance of marine ice-sheets, such as the West Antarctic Ice Sheet, is mostly controlled by their grounding line dynamics. Most numerical models simulating marine ice-sheets involve simplifications and do not include all the stress gradients. First results obtained with a 3D full-Stokes model for the grounded ice-sheet / floating ice-shelf transition, using the finite-element code Elmer/Ice, are presented. The initial geometry, which takes into account a dome and a calving front, has been laterally extruded from a previously investigated 2D flowline geometry. The grounding line migration is computed by solving the contact problem between the ice and the rigid downward sloping bedrock, where a non linear friction law is applied in the two horizontal directions. The evolutions of the sea-air and sea-ice interfaces are determined by the solution of a local transport equation. The consistency between the 3D model and the analogous results of the flowline model is shown by comparing the results in the basic extruded case, with no normal flux through lateral boundaries. Thereafter, spatially non uniform perturbations are introduced, to simulate the grounding line dynamics under fully three-dimensional perturbations.

Dynamic analysis of space structures including elastic, multibody, and control behavior

NASA Technical Reports Server (NTRS)

Pinson, Larry; Soosaar, Keto

1989-01-01

The problem is to develop analysis methods, modeling stategies, and simulation tools to predict with assurance the on-orbit performance and integrity of large complex space structures that cannot be verified on the ground. The problem must incorporate large reliable structural models, multi-body flexible dynamics, multi-tier controller interaction, environmental models including 1g and atmosphere, various on-board disturbances, and linkage to mission-level performance codes. All areas are in serious need of work, but the weakest link is multi-body flexible dynamics.

Ground-water as a nuisance

NASA Astrophysics Data System (ADS)

Straskraba, V.

1984-03-01

In certain circumstances, ground-water causes geotechnical problems and can be considered a nuisance rather than a blessing. The cases where ground-water creates considerable complications include construction, tunnelling, mining, landslides, and land subsidence. The development of hydrogeology as a science has proved over the years to substantially reduce the severe problems and disasterous problems caused by ground-water.

Integrated Controls-Structures Design Methodology for Flexible Spacecraft

NASA Technical Reports Server (NTRS)

Maghami, P. G.; Joshi, S. M.; Price, D. B.

1995-01-01

This paper proposes an approach for the design of flexible spacecraft, wherein the structural design and the control system design are performed simultaneously. The integrated design problem is posed as an optimization problem in which both the structural parameters and the control system parameters constitute the design variables, which are used to optimize a common objective function, thereby resulting in an optimal overall design. The approach is demonstrated by application to the integrated design of a geostationary platform, and to a ground-based flexible structure experiment. The numerical results obtained indicate that the integrated design approach generally yields spacecraft designs that are substantially superior to the conventional approach, wherein the structural design and control design are performed sequentially.

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.

Simulation-Based Rule Generation Considering Readability

PubMed Central

Yahagi, H.; Shimizu, S.; Ogata, T.; Hara, T.; Ota, J.

2015-01-01

Rule generation method is proposed for an aircraft control problem in an airport. Designing appropriate rules for motion coordination of taxiing aircraft in the airport is important, which is conducted by ground control. However, previous studies did not consider readability of rules, which is important because it should be operated and maintained by humans. Therefore, in this study, using the indicator of readability, we propose a method of rule generation based on parallel algorithm discovery and orchestration (PADO). By applying our proposed method to the aircraft control problem, the proposed algorithm can generate more readable and more robust rules and is found to be superior to previous methods. PMID:27347501

Space Environments Testbed

NASA Technical Reports Server (NTRS)

Leucht, David K.; Koslosky, Marie J.; Kobe, David L.; Wu, Jya-Chang C.; Vavra, David A.

2011-01-01

The Space Environments Testbed (SET) is a flight controller data system for the Common Carrier Assembly. The SET-1 flight software provides the command, telemetry, and experiment control to ground operators for the SET-1 mission. Modes of operation (see dia gram) include: a) Boot Mode that is initiated at application of power to the processor card, and runs memory diagnostics. It may be entered via ground command or autonomously based upon fault detection. b) Maintenance Mode that allows for limited carrier health monitoring, including power telemetry monitoring on a non-interference basis. c) Safe Mode is a predefined, minimum power safehold configuration with power to experiments removed and carrier functionality minimized. It is used to troubleshoot problems that occur during flight. d) Operations Mode is used for normal experiment carrier operations. It may be entered only via ground command from Safe Mode.

Optimal Control Based Stiffness Identification of an Ankle-Foot Orthosis Using a Predictive Walking Model

PubMed Central

Sreenivasa, Manish; Millard, Matthew; Felis, Martin; Mombaur, Katja; Wolf, Sebastian I.

2017-01-01

Predicting the movements, ground reaction forces and neuromuscular activity during gait can be a valuable asset to the clinical rehabilitation community, both to understand pathology, as well as to plan effective intervention. In this work we use an optimal control method to generate predictive simulations of pathological gait in the sagittal plane. We construct a patient-specific model corresponding to a 7-year old child with gait abnormalities and identify the optimal spring characteristics of an ankle-foot orthosis that minimizes muscle effort. Our simulations include the computation of foot-ground reaction forces, as well as the neuromuscular dynamics using computationally efficient muscle torque generators and excitation-activation equations. The optimal control problem (OCP) is solved with a direct multiple shooting method. The solution of this problem is physically consistent synthetic neural excitation commands, muscle activations and whole body motion. Our simulations produced similar changes to the gait characteristics as those recorded on the patient. The orthosis-equipped model was able to walk faster with more extended knees. Notably, our approach can be easily tuned to simulate weakened muscles, produces physiologically realistic ground reaction forces and smooth muscle activations and torques, and can be implemented on a standard workstation to produce results within a few hours. These results are an important contribution toward bridging the gap between research methods in computational neuromechanics and day-to-day clinical rehabilitation. PMID:28450833

Experimental Adiabatic Quantum Factorization under Ambient Conditions Based on a Solid-State Single Spin System.

PubMed

Xu, Kebiao; Xie, Tianyu; Li, Zhaokai; Xu, Xiangkun; Wang, Mengqi; Ye, Xiangyu; Kong, Fei; Geng, Jianpei; Duan, Changkui; Shi, Fazhan; Du, Jiangfeng

2017-03-31

The adiabatic quantum computation is a universal and robust method of quantum computing. In this architecture, the problem can be solved by adiabatically evolving the quantum processor from the ground state of a simple initial Hamiltonian to that of a final one, which encodes the solution of the problem. Adiabatic quantum computation has been proved to be a compatible candidate for scalable quantum computation. In this Letter, we report on the experimental realization of an adiabatic quantum algorithm on a single solid spin system under ambient conditions. All elements of adiabatic quantum computation, including initial state preparation, adiabatic evolution (simulated by optimal control), and final state read-out, are realized experimentally. As an example, we found the ground state of the problem Hamiltonian S_{z}I_{z} on our adiabatic quantum processor, which can be mapped to the factorization of 35 into its prime factors 5 and 7.

Experimental Adiabatic Quantum Factorization under Ambient Conditions Based on a Solid-State Single Spin System

NASA Astrophysics Data System (ADS)

Xu, Kebiao; Xie, Tianyu; Li, Zhaokai; Xu, Xiangkun; Wang, Mengqi; Ye, Xiangyu; Kong, Fei; Geng, Jianpei; Duan, Changkui; Shi, Fazhan; Du, Jiangfeng

2017-03-01

The adiabatic quantum computation is a universal and robust method of quantum computing. In this architecture, the problem can be solved by adiabatically evolving the quantum processor from the ground state of a simple initial Hamiltonian to that of a final one, which encodes the solution of the problem. Adiabatic quantum computation has been proved to be a compatible candidate for scalable quantum computation. In this Letter, we report on the experimental realization of an adiabatic quantum algorithm on a single solid spin system under ambient conditions. All elements of adiabatic quantum computation, including initial state preparation, adiabatic evolution (simulated by optimal control), and final state read-out, are realized experimentally. As an example, we found the ground state of the problem Hamiltonian SzIz on our adiabatic quantum processor, which can be mapped to the factorization of 35 into its prime factors 5 and 7.

Web-Altairis: An Internet-Enabled Ground System

NASA Technical Reports Server (NTRS)

Miller, Phil; Coleman, Jason; Gemoets, Darren; Hughes, Kevin

2000-01-01

This paper describes Web-Altairis, an Internet-enabled ground system software package funded by the Advanced Automation and Architectures Branch (Code 588) of NASA's Goddard Space Flight Center. Web-Altairis supports the trend towards "lights out" ground systems, where the control center is unattended and problems are resolved by remote operators. This client/server software runs on most popular platforms and provides for remote data visualization using the rich functionality of the VisAGE toolkit. Web-Altairis also supports satellite commanding over the Internet. This paper describes the structure of Web-Altairis and VisAGE, the underlying technologies, the provisions for security, and our experiences in developing and testing the software.

Machine Learning Control For Highly Reconfigurable High-Order Systems

DTIC Science & Technology

2015-01-02

develop and flight test a Reinforcement Learning based approach for autonomous tracking of ground targets using a fixed wing Unmanned...Reinforcement Learning - based algorithms are developed for learning agents’ time dependent dynamics while also learning to control them. Three algorithms...to a wide range of engineering- based problems . Implementation of these solutions, however, is often complicated by the hysteretic, non-linear,

Flying qualities - A costly lapse in flight-control design

NASA Technical Reports Server (NTRS)

Berry, D. T.

1982-01-01

Generic problems in advanced aircraft with advanced control systems which suffer from control sensitivity, sluggish response, and pilot-induced oscillation tendencies are examined, with a view to improving techniques for eliminating the problems in the design phase. Results of two NASA and NASA/AIAA workshops reached a consensus that flying qualities criteria do not match control system development, control system designers are not relying on past experience in their field, ground-based simulation is relied on too heavily, and communications between flying qualities and control systems engineers need improvement. A summation is offered in that hardware and software have outstripped the pilot's capacity to use the capabilities which new aircraft offer. The flying qualities data base is stressed to be dynamic, and continually redefining the man/machine relationships.

Attitude ground support system for the solar maximum mission spacecraft

NASA Technical Reports Server (NTRS)

Nair, G.

1980-01-01

The SMM attitude ground support system (AGSS) supports the acquisition of spacecraft roll attitude reference, performs the in-flight calibration of the attitude sensor complement, supports onboard control autonomy via onboard computer data base updates, and monitors onboard computer (OBC) performance. Initial roll attitude acquisition is accomplished by obtaining a coarse 3 axis attitude estimate from magnetometer and Sun sensor data and subsequently refining it by processing data from the fixed head star trackers. In-flight calibration of the attitude sensor complement is achieved by processing data from a series of slew maneuvers designed to maximize the observability and accuracy of the appropriate alignments and biases. To ensure autonomy of spacecraft operation, the AGSS selects guide stars and computes sensor occultation information for uplink to the OBC. The onboard attitude control performance is monitored on the ground through periodic attitude determination and processing of OBC data in downlink telemetry. In general, the control performance has met mission requirements. However, software and hardware problems have resulted in sporadic attitude reference losses.

Expert assessments and content analysis of crew communication during ISS missions

NASA Astrophysics Data System (ADS)

Yusupova, Anna

During the last seven years, we have analyzed the communication patterns between ISS crewmembers and mission control personnel and identified a number of different communication styles between these two groups (Gushin et al, 2005). In this paper, we will report on an external validity check we conducted that compares our findings with those of another study using the same research material. For many years the group of psychologists at the Medical Center of Space Flight Control (TCUMOKO) at the Institute for Biomedical Problems (IBMP) in Moscow has been analyzing audio communication sessions of Russian space crews with the ground-based Mission Control during long-duration spaceflight conditions. We compared week by week texts of the standard weekly monitoring reports made by the TsUP psychological group and audiocommunication of space crews with mission control centers. Expert assessments of the crewmembers' psychological state are made by IBMP psychoneurologists on the basis of daily schedule fulfillment, video and audio materials, and psychophysiological data from board. The second approach was based on the crew-ground communication analysis. For both population of messages we applied two corresponding schemas of content analysis. All statements made in communication sessions and weekly reports were divided into three groups in terms of their communication function (Lomov, 1981): 1) informative function (e.g., demands for information, requests, professional slang); 2) socio-regulatory function (e.g., rational consent or discord, operational complaint, refusal to cooperate); and 3) affective (emotional) function (e.g., encouragement, sympathy, emotional consent or discord). Number of statements of the audiocommunication sessions correlated with corresponding functions (informative, regulatory, affective) of communication in weekly monitioring reports made by experts. Crewmembers verbal behavior expresses its psycho-emotional state which is formulated by expert psychologists in weekly reports. This result shows that both approaches (expert assessment and content analysis of crew communication) can provide us with valuable data concerning crew's psychological state. Statistically significant correlations between crew-ground communication and expert assessment parameters testify that the same patterns of crewmembers behavior could be detected by both methods. 1. Lomov B.F. Problem of communication in psychology. // Problem of communication in psychology. Moscow, Nauka, 1981 2. Gushin V., M.D., Yusupova A., Pustinnikova J., Popova I. Crew-ground control communication styles: preliminary results in psychosocial area. // Proceedings of 56th International Astronautical Congress, Fukuoka 2005.

Around Marshall

NASA Image and Video Library

1990-12-03

The primary objective of the STS-35 mission was round the clock observation of the celestial sphere in ultraviolet and X-Ray astronomy with the Astro-1 observatory which consisted of four telescopes: the Hopkins Ultraviolet Telescope (HUT); the Wisconsin Ultraviolet Photo-Polarimeter Experiment (WUPPE); the Ultraviolet Imaging Telescope (UIT); and the Broad Band X-Ray Telescope (BBXRT). The Huntsville Operations Support Center (HOSC) Spacelab Payload Operations Control Center (SL POCC) at the Marshall Space Flight Center (MSFC) was the air/ground communication channel used between the astronauts and ground control teams during the Spacelab missions. Teams of controllers and researchers directed on-orbit science operations, sent commands to the spacecraft, received data from experiments aboard the Space Shuttle, adjusted mission schedules to take advantage of unexpected science opportunities or unexpected results, and worked with crew members to resolve problems with their experiments. Due to loss of data used for pointing and operating the ultraviolet telescopes, MSFC ground teams were forced to aim the telescopes with fine tuning by the flight crew. This photo is an overview of the MSFC Payload Control Room (PCR).

Spacelab

NASA Image and Video Library

1990-12-02

The primary objective of the STS-35 mission was round the clock observation of the celestial sphere in ultraviolet and X-Ray astronomy with the Astro-1 observatory which consisted of four telescopes: the Hopkins Ultraviolet Telescope (HUT); the Wisconsin Ultraviolet Photo-Polarimeter Experiment (WUPPE); the Ultraviolet Imaging Telescope (UIT); and the Broad Band X-Ray Telescope (BBXRT). The Huntsville Operations Support Center (HOSC) Spacelab Payload Operations Control Center (SL POCC) at the Marshall Space Flight Center (MSFC) was the air/ground communication channel used between the astronauts and ground control teams during the Spacelab missions. Teams of controllers and researchers directed on-orbit science operations, sent commands to the spacecraft, received data from experiments aboard the Space Shuttle, adjusted mission schedules to take advantage of unexpected science opportunities or unexpected results, and worked with crew members to resolve problems with their experiments. Due to loss of data used for pointing and operating the ultraviolet telescopes, MSFC ground teams were forced to aim the telescopes with fine tuning by the flight crew. Pictured onboard the shuttle is astronaut Robert Parker using a Manual Pointing Controller (MPC) for the ASTRO-1 mission Instrument Pointing System (IPS).

Around Marshall

NASA Image and Video Library

1990-12-02

The primary objective of the STS-35 mission was round the clock observation of the celestial sphere in ultraviolet and X-Ray astronomy with the Astro-1 observatory which consisted of four telescopes: the Hopkins Ultraviolet Telescope (HUT); the Wisconsin Ultraviolet Photo-Polarimeter Experiment (WUPPE); the Ultraviolet Imaging Telescope (UIT); and the Broad Band X-Ray Telescope (BBXRT). The Huntsville Operations Support Center (HOSC) Spacelab Payload Operations Control Center (SL POCC) at the Marshall Space Flight Center (MSFC) was the air/ground communication channel used between the astronauts and ground control teams during the Spacelab missions. Teams of controllers and researchers directed on-orbit science operations, sent commands to the spacecraft, received data from experiments aboard the Space Shuttle, adjusted mission schedules to take advantage of unexpected science opportunities or unexpected results, and worked with crew members to resolve problems with their experiments. Due to loss of data used for pointing and operating the ultraviolet telescopes, MSFC ground teams were forced to aim the telescopes with fine tuning by the flight crew. This photo captures the activity at the Operations Control Facility during the mission as Dr. Urban and Paul Whitehouse give a “thumbs up”.

Road-Following Formation Control of Autonomous Ground Vehicles

NASA Technical Reports Server (NTRS)

Ono, Masahiro; Droge, Greg; Grip, Havard; Toupet, Olivier; Scrapper, Chris; Rahmani, Amir

2015-01-01

This work presents a novel cooperative path planning for formation keeping robots traversing along a road with obstacles and possible narrow passages. A unique challenge in this problem is a requirement for spatial and temporal coordination between vehicles while ensuring collision and obstacle avoidance.

Treatment of the control mechanisms of light airplanes in the flutter clearance process

NASA Technical Reports Server (NTRS)

Breitbach, E. J.

1979-01-01

It has become more and more evident that many difficulties encountered in the course of aircraft flutter analyses can be traced to strong localized nonlinearities in the control mechanisms. To cope with these problems, more reliable mathematical models paying special attention to control system nonlinearities were established by means of modified ground vibration test procedures in combination with suitably adapted modal synthesis approaches. Three different concepts are presented.

Skylab-EREP studies in computer mapping of terrain in the Cripple Creek-Canon City area of Colorado

NASA Technical Reports Server (NTRS)

Smedes, H. W.; Ranson, K. J.; Holstrom, R. L.

1975-01-01

Multispectral-scanner data from satellites are used as input to computers for automatically mapping terrain classes of ground cover. Some major problems faced in this remote-sensing task include: (1) the effect of mixtures of classes and, primarily because of mixtures, the problem of what constitutes accurate control data, and (2) effects of the atmosphere on spectral responses. The fundamental principles of these problems are presented along with results of studies of them for a test site of Colorado, using LANDSAT-1 data.

Dynamic test results for the CASES ground experiment

NASA Technical Reports Server (NTRS)

Bukley, Angelia P.; Patterson, Alan F.; Jones, Victoria L.

1993-01-01

The Controls, Astrophysics, and Structures Experiment in Space (CASES) Ground Test Facility (GTF) has been developed at Marshall Space Flight Center (MSFC) to provide a facility for the investigation of Controls/Structures Interaction (CSI) phenomena, to support ground testing of a potential shuttle-based CASES flight experiment, and to perform limited boom deployment and retraction dynamics studies. The primary objectives of the ground experiment are to investigate CSI on a test article representative of a Large Space Structure (LSS); provide a platform for Guest Investigators (GI's) to conduct CSI studies; to test and evaluate LSS control methodologies, system identification (ID) techniques, failure mode analysis; and to compare ground test predictions and flight results. The proposed CASES flight experiment consists of a 32 meter deployable/retractable boom at the end of which is an occulting plate. The control objective of the experiment is to maintain alignment of the tip plate (occulter) with a detector located at the base of the boom in the orbiter bay. The tip plate is pointed towards a star, the sun, or the galactic center to collect high-energy X-rays emitted by these sources. The tip plate, boom, and detector comprise a Fourier telescope. The occulting holes in the tip plate are approximately one millimeter in diameter making the alignment requirements quite stringent. Control authority is provided by bidirectional linear thrusters located at the boom tip and Angular Momentum Exchange Devices (AMED's) located at mid-boom and at the tip. The experiment embodies a number of CSI control problems including vibration suppression, pointing a long flexible structure, and disturbance rejection. The CASES GTF is representative of the proposed flight experiment with identical control objectives.

Realization of ground-state artificial skyrmion lattices at room temperature

DOE PAGES

Gilbert, Dustin A.; Maranville, Brian B.; Balk, Andrew L.; ...

2015-10-08

We report that the topological nature of magnetic skyrmions leads to extraordinary properties that provide new insights into fundamental problems of magnetism and exciting potentials for novel magnetic technologies. Prerequisite are systems exhibiting skyrmion lattices at ambient conditions, which have been elusive so far. We demonstrate the realization of artificial Bloch skyrmion lattices over extended areas in their ground state at room temperature by patterning asymmetric magnetic nanodots with controlled circularity on an underlayer with perpendicular magnetic anisotropy (PMA). Polarity is controlled by a tailored magnetic field sequence and demonstrated in magnetometry measurements. The vortex structure is imprinted from themore » dots into the interfacial region of the underlayer via suppression of the PMA by a critical ion-irradiation step. In conclusion, the imprinted skyrmion lattices are identified directly with polarized neutron reflectometry and confirmed by magnetoresistance measurements. Our results demonstrate an exciting platform to explore room-temperature ground-state skyrmion lattices.« less

Research on Scheduling Algorithm for Multi-satellite and Point Target Task on Swinging Mode

NASA Astrophysics Data System (ADS)

Wang, M.; Dai, G.; Peng, L.; Song, Z.; Chen, G.

2012-12-01

Nowadays, using satellite in space to observe ground is an important and major method to obtain ground information. With the development of the scientific technology in the field of space, many fields such as military and economic and other areas have more and more requirement of space technology because of the benefits of the satellite's widespread, timeliness and unlimited of area and country. And at the same time, because of the wide use of all kinds of satellites, sensors, repeater satellites and ground receiving stations, ground control system are now facing great challenge. Therefore, how to make the best value of satellite resources so as to make full use of them becomes an important problem of ground control system. Satellite scheduling is to distribute the resource to all tasks without conflict to obtain the scheduling result so as to complete as many tasks as possible to meet user's requirement under considering the condition of the requirement of satellites, sensors and ground receiving stations. Considering the size of the task, we can divide tasks into point task and area task. This paper only considers point targets. In this paper, a description of satellite scheduling problem and a chief introduction of the theory of satellite scheduling are firstly made. We also analyze the restriction of resource and task in scheduling satellites. The input and output flow of scheduling process are also chiefly described in the paper. On the basis of these analyses, we put forward a scheduling model named as multi-variable optimization model for multi-satellite and point target task on swinging mode. In the multi-variable optimization model, the scheduling problem is transformed the parametric optimization problem. The parameter we wish to optimize is the swinging angle of every time-window. In the view of the efficiency and accuracy, some important problems relating the satellite scheduling such as the angle relation between satellites and ground targets, positive and negative swinging angle and the computation of time window are analyzed and discussed. And many strategies to improve the efficiency of this model are also put forward. In order to solve the model, we bring forward the conception of activity sequence map. By using the activity sequence map, the activity choice and the start time of the activity can be divided. We also bring forward three neighborhood operators to search the result space. The front movement remaining time and the back movement remaining time are used to analyze the feasibility to generate solution from neighborhood operators. Lastly, the algorithm to solve the problem and model is put forward based genetic algorithm. Population initialization, crossover operator, mutation operator, individual evaluation, collision decrease operator, select operator and collision elimination operator is designed in the paper. Finally, the scheduling result and the simulation for a practical example on 5 satellites and 100 point targets with swinging mode is given, and the scheduling performances are also analyzed while the swinging angle in 0, 5, 10, 15, 25. It can be shown by the result that the model and the algorithm are more effective than those ones without swinging mode.

Lessons Learned from the Node 1 Atmosphere Control and Storage and Water Recovery and Management Subsystem Design

NASA Technical Reports Server (NTRS)

Williams, David E.

2010-01-01

Node 1 flew to the International Space Station (ISS) on Flight 2A during December 1998. To date the National Aeronautics and Space Administration (NASA) has learned a lot of lessons from this module based on its history of approximately two years of acceptance testing on the ground and currently its twelve years on-orbit. This paper will provide an overview of the ISS Environmental Control and Life Support (ECLS) design of the Node 1 Atmosphere Control and Storage (ACS) and Water Recovery and Management (WRM) subsystems and it will document some of the lessons that have been learned to date for these subsystems based on problems prelaunch, problems encountered on-orbit, and operational problems/concerns. It is hoped that documenting these lessons learned from ISS will help in preventing them in future Programs.

Spillover, nonlinearity, and flexible structures

NASA Technical Reports Server (NTRS)

Bass, Robert W.; Zes, Dean

1991-01-01

Many systems whose evolution in time is governed by Partial Differential Equations (PDEs) are linearized around a known equilibrium before Computer Aided Control Engineering (CACE) is considered. In this case, there are infinitely many independent vibrational modes, and it is intuitively evident on physical grounds that infinitely many actuators would be needed in order to control all modes. A more precise, general formulation of this grave difficulty (spillover problem) is due to A.V. Balakrishnan. A possible route to circumvention of this difficulty lies in leaving the PDE in its original nonlinear form, and adding the essentially finite dimensional control action prior to linearization. One possibly applicable technique is the Liapunov Schmidt rigorous reduction of singular infinite dimensional implicit function problems to finite dimensional implicit function problems. Omitting details of Banach space rigor, the formalities of this approach are given.

Lessons Learned from the Node 1 Atmosphere Control and Storage and Water Recovery and Management Subsystem Design

NASA Technical Reports Server (NTRS)

Williams, David E.

2011-01-01

Node 1 flew to the International Space Station (ISS) on Flight 2A during December 1998. To date the National Aeronautics and Space Administration (NASA) has learned a lot of lessons from this module based on its history of approximately two years of acceptance testing on the ground and currently its twelve years on-orbit. This paper will provide an overview of the ISS Environmental Control and Life Support (ECLS) design of the Node 1 Atmosphere Control and Storage (ACS) and Water Recovery and Management (WRM) subsystems and it will document some of the lessons that have been learned to date for these subsystems based on problems prelaunch, problems encountered on-orbit, and operational problems/concerns. It is hoped that documenting these lessons learned from ISS will help in preventing them in future Programs.

Ground control failures. A pictorial view of case studies

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

Peng, S.S.

2007-07-01

The book shows, in pictorial views, many forms and/or stages of types of failures in mines, for instance, cutter, roof falls, and cribs. In each case, the year of occurrence is stated in the beginning so that the environment or technological background under which it occurred are reflected. The narrative than begins with the mining and geological conditions, followed by a description of the ground control problems and recommended solutions and results, if any. The sections cover failure of pillars, roof falls, longwall, roof bolting, multiple-seam mining, floor heave, longwall, flooding and weathering of coal, old workings, and shortwall andmore » thin-seam plow longwall.« less

Evaluation of emission control strategies for airfield operations at the Los Angeles and San Francisco International Airports. Final report

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

Gelinas, C.G.

1978-08-01

This report reviews potential air pollutant emission reductions which could be achieved by various strategies to control airfield operations at Los Angeles and San Francisco International Airports, and examines safety problems, cost impacts, potential fuel savings, time frame for strategy implementation, and potential regulatory and jurisdictional conflicts associated with each strategy. Airfield emission sources studied included aircraft operation in the idle, taxi, takeoff, and landing modes; ground service vehicles; fuel handling and storage; and aircraft engine maintenance. Nineteen potential strategies were identified, and seven strategies were selected for detailed analysis and examination after a preliminary evaluation. Two strategies, aircraft towingmore » and reducing the number of operating engines on the ground, appear to provide the most significant emission reduction. Both of these strategies offer potential reductions in the range of 20 to 40 percent of the carbon monoxide and nitrogen oxides which are currently emitted by ground operations. The aircraft towing strategy also offers a comparable improvement in suspended particulate matter emissions. When the overall feasibility of each strategy is evaluated, the strategy to reduce the number of operating engines appears to be the most viable since its implementation would result in fuel savings, no apparent safety problems, and it can be implemented immediately.« less

Solving Quantum Ground-State Problems with Nuclear Magnetic Resonance

PubMed Central

Li, Zhaokai; Yung, Man-Hong; Chen, Hongwei; Lu, Dawei; Whitfield, James D.; Peng, Xinhua; Aspuru-Guzik, Alán; Du, Jiangfeng

2011-01-01

Quantum ground-state problems are computationally hard problems for general many-body Hamiltonians; there is no classical or quantum algorithm known to be able to solve them efficiently. Nevertheless, if a trial wavefunction approximating the ground state is available, as often happens for many problems in physics and chemistry, a quantum computer could employ this trial wavefunction to project the ground state by means of the phase estimation algorithm (PEA). We performed an experimental realization of this idea by implementing a variational-wavefunction approach to solve the ground-state problem of the Heisenberg spin model with an NMR quantum simulator. Our iterative phase estimation procedure yields a high accuracy for the eigenenergies (to the 10−5 decimal digit). The ground-state fidelity was distilled to be more than 80%, and the singlet-to-triplet switching near the critical field is reliably captured. This result shows that quantum simulators can better leverage classical trial wave functions than classical computers PMID:22355607

The principle of superposition and its application in ground-water hydraulics

USGS Publications Warehouse

Reilly, Thomas E.; Franke, O. Lehn; Bennett, Gordon D.

1987-01-01

The principle of superposition, a powerful mathematical technique for analyzing certain types of complex problems in many areas of science and technology, has important applications in ground-water hydraulics and modeling of ground-water systems. The principle of superposition states that problem solutions can be added together to obtain composite solutions. This principle applies to linear systems governed by linear differential equations. This report introduces the principle of superposition as it applies to ground-water hydrology and provides background information, discussion, illustrative problems with solutions, and problems to be solved by the reader.

Distributed Method to Optimal Profile Descent

NASA Astrophysics Data System (ADS)

Kim, Geun I.

Current ground automation tools for Optimal Profile Descent (OPD) procedures utilize path stretching and speed profile change to maintain proper merging and spacing requirements at high traffic terminal area. However, low predictability of aircraft's vertical profile and path deviation during decent add uncertainty to computing estimated time of arrival, a key information that enables the ground control center to manage airspace traffic effectively. This paper uses an OPD procedure that is based on a constant flight path angle to increase the predictability of the vertical profile and defines an OPD optimization problem that uses both path stretching and speed profile change while largely maintaining the original OPD procedure. This problem minimizes the cumulative cost of performing OPD procedures for a group of aircraft by assigning a time cost function to each aircraft and a separation cost function to a pair of aircraft. The OPD optimization problem is then solved in a decentralized manner using dual decomposition techniques under inter-aircraft ADS-B mechanism. This method divides the optimization problem into more manageable sub-problems which are then distributed to the group of aircraft. Each aircraft solves its assigned sub-problem and communicate the solutions to other aircraft in an iterative process until an optimal solution is achieved thus decentralizing the computation of the optimization problem.

Proceedings of Workshop XVI; The dynamic characteristics of faulting inferred from recordings of strong ground motion

USGS Publications Warehouse

Boatwright, John; Jacobson, Muriel L.

1982-01-01

The strong ground motions radiated by earthquake faulting are controlled by the dynamic characteristics of the faulting process. Although this assertion seems self-evident, seismologists have only recently begun to derive and test quantitative relations between common measures of strong ground motion and the dynamic characteristics of faulting. Interest in this problem has increased dramatically in past several years, however, resulting in a number of important advances. The research presented in this workshop is a significant part of this scientific development. Watching this development occur through the work of many scientists is exciting; to be able to gather a number of these scientists together in one workshop is a remarkable opportunity.

Combined monitoring, decision and control model for the human operator in a command and control desk

NASA Technical Reports Server (NTRS)

Muralidharan, R.; Baron, S.

1978-01-01

A report is given on the ongoing efforts to mode the human operator in the context of the task during the enroute/return phases in the ground based control of multiple flights of remotely piloted vehicles (RPV). The approach employed here uses models that have their analytical bases in control theory and in statistical estimation and decision theory. In particular, it draws heavily on the modes and the concepts of the optimal control model (OCM) of the human operator. The OCM is being extended into a combined monitoring, decision, and control model (DEMON) of the human operator by infusing decision theoretic notions that make it suitable for application to problems in which human control actions are infrequent and in which monitoring and decision-making are the operator's main activities. Some results obtained with a specialized version of DEMON for the RPV control problem are included.

Systems engineering and integration of control centers in support of multiple programs. [ground control for STS payloads and unmanned vehicles

NASA Technical Reports Server (NTRS)

Miller, David N.

1989-01-01

The NASA Johnson Space Center's new Multiprogram Control Center (MPCC) addresses the control requirements of complex STS payloads as well as unmanned vehicles. An account is given of the relationship of the MPCC to the STS Mission Control Center, with a view to significant difficulties that may be encountered and solutions thus far devised for generic problems. Examples of MPCC workstation applications encompass telemetry decommutation, engineering unit conversion, data-base management, trajectory processing, and flight design.

Mission Manager Area of the Spacelab Payload Operations Control Center (SL POCC)

NASA Technical Reports Server (NTRS)

1990-01-01

The primary objective of the STS-35 mission was round the clock observation of the celestial sphere in ultraviolet and X-Ray astronomy with the Astro-1 observatory which consisted of four telescopes: the Hopkins Ultraviolet Telescope (HUT); the Wisconsin Ultraviolet Photo-Polarimeter Experiment (WUPPE); the Ultraviolet Imaging Telescope (UIT); and the Broad Band X-Ray Telescope (BBXRT). The Huntsville Operations Support Center (HOSC) Spacelab Payload Operations Control Center (SL POCC) at the Marshall Space Flight Center (MSFC) was the air/ground communication channel used between the astronauts and ground control teams during the Spacelab missions. Teams of controllers and researchers directed on-orbit science operations, sent commands to the spacecraft, received data from experiments aboard the Space Shuttle, adjusted mission schedules to take advantage of unexpected science opportunities or unexpected results, and worked with crew members to resolve problems with their experiments. Pictured is Jack Jones in the Mission Manager Area.

The automatic human

NASA Technical Reports Server (NTRS)

Billings, Charles

1991-01-01

An overview is presented of the growth and role of automation in civil aircraft operations for both cockpit management and ground control. NASA has initiated a research program centered on furthering automation and developing a consistent and rational philosophy of human centered aircraft and air traffic control automation. Introduction of the NASA Aviation Safety Reporting System (ASRS) has proved successful in bringing together pilots and ground controllers to report incidents of operational anomalies that can then be analyzed, leading to corrective action to prevent similar reoccurrences. Attention is given to the growing trend of extensive automation in the cockpit that appears to be leading to a diminution of management control of the aircraft by the decreasing number of flight crew members. A majority of reports indicate that there is a serious mismatch between new aircraft capabilities and ATC procedures, which were designed for older aircraft. ASRS has also kept research oriented toward real problems and community needs.

The F-18 High Alpha Research Vehicle: A High-Angle-of-Attack Testbed Aircraft

NASA Technical Reports Server (NTRS)

Regenie, Victoria; Gatlin, Donald; Kempel, Robert; Matheny, Neil

1992-01-01

The F-18 High Alpha Research Vehicle is the first thrust-vectoring testbed aircraft used to study the aerodynamics and maneuvering available in the poststall flight regime and to provide the data for validating ground prediction techniques. The aircraft includes a flexible research flight control system and full research instrumentation. The capability to control the vehicle at angles of attack up to 70 degrees is also included. This aircraft was modified by adding a pitch and yaw thrust-vectoring system. No significant problems occurred during the envelope expansion phase of the program. This aircraft has demonstrated excellent control in the wing rock region and increased rolling performance at high angles of attack. Initial pilot reports indicate that the increased capability is desirable although some difficulty in judging the size and timing of control inputs was observed. The aircraft, preflight ground testing and envelope expansion flight tests are described.

Computing eigenfunctions and eigenvalues of boundary-value problems with the orthogonal spectral renormalization method

NASA Astrophysics Data System (ADS)

Cartarius, Holger; Musslimani, Ziad H.; Schwarz, Lukas; Wunner, Günter

2018-03-01

The spectral renormalization method was introduced in 2005 as an effective way to compute ground states of nonlinear Schrödinger and Gross-Pitaevskii type equations. In this paper, we introduce an orthogonal spectral renormalization (OSR) method to compute ground and excited states (and their respective eigenvalues) of linear and nonlinear eigenvalue problems. The implementation of the algorithm follows four simple steps: (i) reformulate the underlying eigenvalue problem as a fixed-point equation, (ii) introduce a renormalization factor that controls the convergence properties of the iteration, (iii) perform a Gram-Schmidt orthogonalization process in order to prevent the iteration from converging to an unwanted mode, and (iv) compute the solution sought using a fixed-point iteration. The advantages of the OSR scheme over other known methods (such as Newton's and self-consistency) are (i) it allows the flexibility to choose large varieties of initial guesses without diverging, (ii) it is easy to implement especially at higher dimensions, and (iii) it can easily handle problems with complex and random potentials. The OSR method is implemented on benchmark Hermitian linear and nonlinear eigenvalue problems as well as linear and nonlinear non-Hermitian PT -symmetric models.

Adiabatic quantum computation with neutral atoms via the Rydberg blockade

NASA Astrophysics Data System (ADS)

Goyal, Krittika; Deutsch, Ivan

2011-05-01

We study a trapped-neutral-atom implementation of the adiabatic model of quantum computation whereby the Hamiltonian of a set of interacting qubits is changed adiabatically so that its ground state evolves to the desired output of the algorithm. We employ the ``Rydberg blockade interaction,'' which previously has been used to implement two-qubit entangling gates in the quantum circuit model. Here it is employed via off-resonant virtual dressing of the excited levels, so that atoms always remain in the ground state. The resulting dressed-Rydberg interaction is insensitive to the distance between the atoms within a certain blockade radius, making this process robust to temperature and vibrational fluctuations. Single qubit interactions are implemented with global microwaves and atoms are locally addressed with light shifts. With these ingredients, we study a protocol to implement the two-qubit Quadratic Unconstrained Binary Optimization (QUBO) problem. We model atom trapping, addressing, coherent evolution, and decoherence. We also explore collective control of the many-atom system and generalize the QUBO problem to multiple qubits. We study a trapped-neutral-atom implementation of the adiabatic model of quantum computation whereby the Hamiltonian of a set of interacting qubits is changed adiabatically so that its ground state evolves to the desired output of the algorithm. We employ the ``Rydberg blockade interaction,'' which previously has been used to implement two-qubit entangling gates in the quantum circuit model. Here it is employed via off-resonant virtual dressing of the excited levels, so that atoms always remain in the ground state. The resulting dressed-Rydberg interaction is insensitive to the distance between the atoms within a certain blockade radius, making this process robust to temperature and vibrational fluctuations. Single qubit interactions are implemented with global microwaves and atoms are locally addressed with light shifts. With these ingredients, we study a protocol to implement the two-qubit Quadratic Unconstrained Binary Optimization (QUBO) problem. We model atom trapping, addressing, coherent evolution, and decoherence. We also explore collective control of the many-atom system and generalize the QUBO problem to multiple qubits. We acknowledge funding from the AQUARIUS project, Sandia National Laboratories

Lessons Learned from the Node 1 Temperature and Humidity Control Subsystem Design

NASA Technical Reports Server (NTRS)

Williams, David E.

2010-01-01

Node 1 flew to the International Space Station (ISS) on Flight 2A during December 1998. To date the National Aeronautics and Space Administration (NASA) has learned a lot of lessons from this module based on its history of approximately two years of acceptance testing on the ground and currently its twelve years on-orbit. This paper will provide an overview of the ISS Environmental Control and Life Support (ECLS) design of the Node 1 Temperature and Humidity Control (THC) subsystem and it will document some of the lessons that have been learned to date for this subsystem and it will document some of the lessons that have been learned to date for these subsystems based on problems prelaunch, problems encountered on-orbit, and operational problems/concerns. It is hoped that documenting these lessons learned from ISS will help in preventing them in future Programs. 1

Grounding of space structures

NASA Astrophysics Data System (ADS)

Bosela, P. A.; Fertis, D. G.; Shaker, F. J.

1992-09-01

Space structures, such as the Space Station solar arrays, must be extremely light-weight, flexible structures. Accurate prediction of the natural frequencies and mode shapes is essential for determining the structural adequacy of components, and designing a controls system. The tension pre-load in the 'blanket' of photovoltaic solar collectors, and the free/free boundary conditions of a structure in space, causes serious reservations on the use of standard finite element techniques of solution. In particular, a phenomenon known as 'grounding', or false stiffening, of the stiffness matrix occurs during rigid body rotation. This paper examines the grounding phenomenon in detail. Numerous stiffness matrices developed by others are examined for rigid body rotation capability, and found lacking. A force imbalance inherent in the formulations examined is the likely cause of the grounding problem, suggesting the need for a directed force formulation.

Preliminary PANSAT ground station software design and use of an expert system to analyze telemetry

NASA Astrophysics Data System (ADS)

Lawrence, Gregory W.

1994-03-01

The Petite Amateur Navy Satellite (PANSAT) is a communications satellite designed to be used by civilian amateur radio operators. A master ground station is being built at the Naval Postgraduate School. This computer system performs satellite commands, displays telemetry, trouble-shoots problems, and passes messages. The system also controls an open loop tracking antenna. This paper concentrates on the telemetry display, decoding, and interpretation through artificial intelligence (AI). The telemetry is displayed in an easily interpretable format, so that any user can understand the current health of the satellite and be cued as to any problems and possible solutions. Only the master ground station has the ability to receive all telemetry and send commands to the spacecraft; civilian ham users do not have access to this information. The telemetry data is decommutated and analyzed before it is displayed to the user, so that the raw data will not have to be interpreted by ground users. The analysis will use CLIPS imbedded in the code, and derive its inputs from telemetry decommutation. The program is an expert system using a forward chaining set of rules based on the expected operation and parameters of the satellite. By building the rules during the construction and design of the satellite, the telemetry can be well understood and interpreted after the satellite is launched and the designers may no longer be available to provide input to the problem.

Around Marshall

NASA Image and Video Library

1990-12-12

The primary objective of the STS-35 mission was round the clock observation of the celestial sphere in ultraviolet and X-Ray astronomy with the Astro-1 observatory which consisted of four telescopes: the Hopkins Ultraviolet Telescope (HUT); the Wisconsin Ultraviolet Photo-Polarimeter Experiment (WUPPE); the Ultraviolet Imaging Telescope (UIT); and the Broad Band X-Ray Telescope (BBXRT). The Huntsville Operations Support Center (HOSC) Spacelab Payload Operations Control Center (SL POCC) at the Marshall Space Flight Center (MSFC) was the air/ground communication channel used between the astronauts and ground control teams during the Spacelab missions. Teams of controllers and researchers directed on-orbit science operations, sent commands to the spacecraft, received data from experiments aboard the Space Shuttle, adjusted mission schedules to take advantage of unexpected science opportunities or unexpected results, and worked with crew members to resolve problems with their experiments. Due to loss of data used for pointing and operating the ultraviolet telescopes, MSFC ground teams were forced to aim the telescopes with fine tuning by the flight crew. This photo captures the activity of WUPPE data review at the Science Operations Area during the mission.

Around Marshall

NASA Image and Video Library

1990-12-04

The primary objective of the STS-35 mission was round the clock observation of the celestial sphere in ultraviolet and X-Ray astronomy with the Astro-1 observatory which consisted of four telescopes: the Hopkins Ultraviolet Telescope (HUT); the Wisconsin Ultraviolet Photo-Polarimeter Experiment (WUPPE); the Ultraviolet Imaging Telescope (UIT); and the Broad Band X-Ray Telescope (BBXRT). The Huntsville Operations Support Center (HOSC) Spacelab Payload Operations Control Center (SL POCC) at the Marshall Space Flight Center (MSFC) was the air/ground communication channel used between the astronauts and ground control teams during the Spacelab missions. Teams of controllers and researchers directed on-orbit science operations, sent commands to the spacecraft, received data from experiments aboard the Space Shuttle, adjusted mission schedules to take advantage of unexpected science opportunities or unexpected results, and worked with crew members to resolve problems with their experiments. Due to loss of data used for pointing and operating the ultraviolet telescopes, MSFC ground teams were forced to aim the telescopes with fine tuning by the flight crew. This photo captures a press briefing at MSFC during STS-35, ASTRO-1 Mission.

Around Marshall

NASA Image and Video Library

1990-12-02

The primary objective of the STS-35 mission was round the clock observation of the celestial sphere in ultraviolet and X-Ray astronomy with the Astro-1 observatory which consisted of four telescopes: the Hopkins Ultraviolet Telescope (HUT); the Wisconsin Ultraviolet Photo-Polarimeter Experiment (WUPPE); the Ultraviolet Imaging Telescope (UIT); and the Broad Band X-Ray Telescope (BBXRT). The Huntsville Operations Support Center (HOSC) Spacelab Payload Operations Control Center (SL POCC) at the Marshall Space Flight Center (MSFC) was the air/ground communication channel used between the astronauts and ground control teams during the Spacelab missions. Teams of controllers and researchers directed on-orbit science operations, sent commands to the spacecraft, received data from experiments aboard the Space Shuttle, adjusted mission schedules to take advantage of unexpected science opportunities or unexpected results, and worked with crew members to resolve problems with their experiments. Due to loss of data used for pointing and operating the ultraviolet telescopes, MSFC ground teams were forced to aim the telescopes with fine tuning by the flight crew. This photo captures the activity of viewing HUT data in the Mission Manager Actions Room during the mission.

Around Marshall

NASA Image and Video Library

1990-12-02

The primary objective of the STS-35 mission was round the clock observation of the celestial sphere in ultraviolet and X-Ray astronomy with the Astro-1 observatory which consisted of four telescopes: the Hopkins Ultraviolet Telescope (HUT); the Wisconsin Ultraviolet Photo-Polarimeter Experiment (WUPPE); the Ultraviolet Imaging Telescope (UIT); and the Broad Band X-Ray Telescope (BBXRT). The Huntsville Operations Support Center (HOSC) Spacelab Payload Operations Control Center (SL POCC) at the Marshall Space Flight Center (MSFC) was the air/ground communication channel used between the astronauts and ground control teams during the Spacelab missions. Teams of controllers and researchers directed on-orbit science operations, sent commands to the spacecraft, received data from experiments aboard the Space Shuttle, adjusted mission schedules to take advantage of unexpected science opportunities or unexpected results, and worked with crew members to resolve problems with their experiments. Due to loss of data used for pointing and operating the ultraviolet telescopes, MSFC ground teams were forced to aim the telescopes with fine tuning by the flight crew. This photo captures the activities at the Mission Manager Actions Room during the mission.

Around Marshall

NASA Image and Video Library

1990-12-02

The primary objective of the STS-35 mission was round the clock observation of the celestial sphere in ultraviolet and X-Ray astronomy with the Astro-1 observatory which consisted of four telescopes: the Hopkins Ultraviolet Telescope (HUT); the Wisconsin Ultraviolet Photo-Polarimeter Experiment (WUPPE); the Ultraviolet Imaging Telescope (UIT); and the Broad Band X-Ray Telescope (BBXRT). The Huntsville Operations Support Center (HOSC) Spacelab Payload Operations Control Center (SL POCC) at the Marshall Space Flight Center (MSFC) was the air/ground communication channel used between the astronauts and ground control teams during the Spacelab missions. Teams of controllers and researchers directed on-orbit science operations, sent commands to the spacecraft, received data from experiments aboard the Space Shuttle, adjusted mission schedules to take advantage of unexpected science opportunities or unexpected results, and worked with crew members to resolve problems with their experiments. Due to loss of data used for pointing and operating the ultraviolet telescopes, MSFC ground teams were forced to aim the telescopes with fine tuning by the flight crew. This photo captures the activity of BBKRT data review in the Science Operations Area during the mission.

Changes in pulse rate, respiratory rate, blood oxygenation, perfusion index, skin conductance, and their variability induced during and after grounding human subjects for 40 minutes.

PubMed

Chevalier, Gaetan

2010-01-01

Previous studies have shown that grounding produces quantifiable physiologic changes. This study was set up to reproduce and expand earlier electrophysiologic and physiologic parameters measured immediately after grounding with improved methodology and state-of-the-art equipment. A multiparameter double-blind experiment was conducted with 14 men and 14 women (age range: 18-80) in relatively good health. Subjects were screened for health problems using a commonly used health questionnaire. They were seated in a comfortable recliner and measured during 2-hour grounding sessions, leaving time for signals to stabilize before, during, and after grounding (40 minutes for each period). Sham 2-hour grounding sessions were also recorded with the same subjects as controls. This report presents results for 5 of the 18 parameters measured. The parameters reported here are: skin conductance (SC), blood oxygenation (BO), respiratory rate (RR), pulse rate (PR), and perfusion index (PI). This study was performed in a rented facility in Encinitas, California. The facility was chosen in a quiet area for its very low electromagnetic noise. For each session, statistical analyses were performed on four 10-minute segments: before and after grounding (sham grounding for control session) and before and after ungrounding (sham ungrounding). There was an immediate decrease in SC at grounding and an immediate increase at ungrounding on all subjects. RR increased during grounding, and the effect lasted after ungrounding. RR variance increased immediately after grounding then decreased. BO variance decreased during grounding, followed by a dramatic increase after ungrounding. PR and PI variances increased toward the end of the grounding period, and this change persisted after ungrounding. These results warrant further research to determine how grounding affects the body. Grounding could become important for relaxation, health maintenance and disease prevention.

Dynamic analysis of space-related linear and non-linear structures

NASA Technical Reports Server (NTRS)

Bosela, Paul A.; Shaker, Francis J.; Fertis, Demeter G.

1990-01-01

In order to be cost effective, space structures must be extremely light weight, and subsequently, very flexible structures. The power system for Space Station Freedom is such a structure. Each array consists of a deployable truss mast and a split blanket of photo-voltaic solar collectors. The solar arrays are deployed in orbit, and the blanket is stretched into position as the mast is extended. Geometric stiffness due to the preload make this an interesting non-linear problem. The space station will be subjected to various dynamic loads, during shuttle docking, solar tracking, attitude adjustment, etc. Accurate prediction of the natural frequencies and mode shapes of the space station components, including the solar arrays, is critical for determining the structural adequacy of the components, and for designing a dynamic control system. The process used in developing and verifying the finite element dynamic model of the photo-voltaic arrays is documented. Various problems were identified, such as grounding effects due to geometric stiffness, large displacement effects, and pseudo-stiffness (grounding) due to lack of required rigid body modes. Analysis techniques, such as development of rigorous solutions using continuum mechanics, finite element solution sequence altering, equivalent systems using a curvature basis, Craig-Bampton superelement approach, and modal ordering schemes were utilized. The grounding problems associated with the geometric stiffness are emphasized.

Dynamic analysis of space-related linear and non-linear structures

NASA Technical Reports Server (NTRS)

Bosela, Paul A.; Shaker, Francis J.; Fertis, Demeter G.

1990-01-01

In order to be cost effective, space structures must be extremely light weight, and subsequently, very flexible structures. The power system for Space Station Freedom is such a structure. Each array consists of a deployable truss mast and a split blanket of photovoltaic solar collectors. The solar arrays are deployed in orbit, and the blanket is stretched into position as the mast is extended. Geometric stiffness due to the preload make this an interesting non-linear problem. The space station will be subjected to various dynamic loads, during shuttle docking, solar tracking, attitude adjustment, etc. Accurate prediction of the natural frequencies and mode shapes of the space station components, including the solar arrays, is critical for determining the structural adequacy of the components, and for designing a dynamic controls system. The process used in developing and verifying the finite element dynamic model of the photo-voltaic arrays is documented. Various problems were identified, such as grounding effects due to geometric stiffness, large displacement effects, and pseudo-stiffness (grounding) due to lack of required rigid body modes. Analysis techniques, such as development of rigorous solutions using continuum mechanics, finite element solution sequence altering, equivalent systems using a curvature basis, Craig-Bampton superelement approach, and modal ordering schemes were utilized. The grounding problems associated with the geometric stiffness are emphasized.

Smarter Software For Enhanced Vehicle Health Monitoring and Inter-Planetary Exploration

NASA Technical Reports Server (NTRS)

Larson, William E.; Goodrich, Charles H.; Steinrock, Todd (Technical Monitor)

2001-01-01

The existing philosophy for space mission control was born in the early days of the space program when technology did not exist to put significant control responsibility onboard the spacecraft. NASA relied on a team of ground control experts to troubleshoot systems when problems occurred. As computing capability improved, more responsibility was handed over to the systems software. However, there is still a large contingent of both launch and flight controllers supporting each mission. New technology can update this philosophy to increase mission assurance and reduce the cost of inter-planetary exploration. The advent of model-based diagnosis and intelligent planning software enables spacecraft to handle most routine problems automatically and allocate resources in a flexible way to realize mission objectives. The manifests for recent missions include multiple subsystems and complex experiments. Spacecraft must operate at longer distances from earth where communications delays make earthbound command and control impractical. NASA's Ames Research Center (ARC) has demonstrated the utility of onboard diagnosis and planning with the Remote Agent experiment in 1999. KSC has pioneered model-based diagnosis and demonstrated its utility for ground support operations. KSC and ARC are cooperating in research to improve the state of the art of this technology. This paper highlights model-based reasoning applications for Moon and Mars missions including in-situ resource utilization and enhanced vehicle health monitoring.

Interaction of marine geodesy, satellite technology and ocean physics

NASA Technical Reports Server (NTRS)

Mourad, A. G.; Fubara, D. M. J.

1972-01-01

The possible applications of satellite technology in marine geodesy and geodetic related ocean physics were investigated. Four major problems were identified in the areas of geodesy and ocean physics: (1) geodetic positioning and control establishment; (2) sea surface topography and geoid determination; (3) geodetic applications to ocean physics; and (4) ground truth establishment. It was found that satellite technology can play a major role in their solution. For solution of the first problem, the use of satellite geodetic techniques, such as Doppler and C-band radar ranging, is demonstrated to fix the three-dimensional coordinates of marine geodetic control if multi-satellite passes are used. The second problem is shown to require the use of satellite altimetry, along with accurate knowledge of ocean-dynamics parameters such as sea state, ocean tides, and mean sea level. The use of both conventional and advanced satellite techniques appeared to be necessary to solve the third and fourth problems.

Solar heating and cooling system installed at RKL Controls Company, Lumberton, New Jersey

NASA Technical Reports Server (NTRS)

1981-01-01

The final results of the design and operation of a computer controlled solar heated and cooled 40,000 square foot manufacturing building, sales office, and computer control center/display room are summarized. The system description, test data, major problems and resolutions, performance, operation and maintenance manual, equipment manufacturers' literature, and as-built drawings are presented. The solar system is composed of 6,000 square feet of flat plate collectors, external above ground storage subsystem, controls, absorption chiller, heat recovery, and a cooling tower.

Optical communications for transport aircraft

NASA Technical Reports Server (NTRS)

Stengel, Robert

1994-01-01

Optical communications for transport aircraft are discussed. The problem involves: increasing demand for radio-frequency bands from an enlarging pool of users (aircraft, ground and sea vehicles, fleet operators, traffic control centers, and commercial radio and television); desirability of providing high-bandwidth dedicated communications to and from every aircraft in the National Airspace System; need to support communications, navigation, and surveillance for a growing number of aircraft; and improved meteorological observations by use of probe aircraft. The solution involves: optical signal transmission support very high data rates; optical transmission of signals between aircraft, orbiting satellites, and ground stations, where unobstructed line-of-sight is available; conventional radio transmissions of signals between aircraft and ground stations, where optical line-of-sight is unavailable; and radio priority given to aircraft in weather.

The principle of superposition and its application in ground-water hydraulics

USGS Publications Warehouse

Reilly, T.E.; Franke, O.L.; Bennett, G.D.

1984-01-01

The principle of superposition, a powerful methematical technique for analyzing certain types of complex problems in many areas of science and technology, has important application in ground-water hydraulics and modeling of ground-water systems. The principle of superposition states that solutions to individual problems can be added together to obtain solutions to complex problems. This principle applies to linear systems governed by linear differential equations. This report introduces the principle of superposition as it applies to groundwater hydrology and provides background information, discussion, illustrative problems with solutions, and problems to be solved by the reader. (USGS)

Application of empirical and linear methods to VSTOL powered-lift aerodynamics

NASA Technical Reports Server (NTRS)

Margason, Richard; Kuhn, Richard

1988-01-01

Available prediction methods applied to problems of aero/propulsion interactions for short takeoff and vertical landing (STOVL) aircraft are critically reviewed and an assessment of their strengths and weaknesses provided. The first two problems deal with aerodynamic performance effects during hover: (1) out-of-ground effect, and (2) in-ground effect. The first can be evaluated for some multijet cases; however, the second problem is very difficult to evaluate for multijets. The ground-environment effects due to wall jets and fountain flows directly affect hover performance. In a related problem: (3) hot-gas ingestion affects the engine operation. Both of these problems as well as jet noise affect the ability of people to work near the aircraft and the ability of the aircraft to operate near the ground. Additional problems are: (4) the power-augmented lift due to jet-flap effects (both in- and out-of-ground effects), and (5) the direct jet-lift effects during short takeoff and landing (STOL) operations. The final problem: (6) is the aerodynamic/propulsion interactions in transition between hover and wing-borne flight. Areas where modern CFD methods can provide improvements to current computational capabilities are identified.

Teaching English in a Multilingual Context: The Algerian Case.

ERIC Educational Resources Information Center

Miliani, Mohamed

2001-01-01

Algeria's educational system and language usage are politically controlled. As French loses its ground, English is being heralded as a solution to the country's problems. Popular vernaculars are banned. Language policy is the result of political takeovers. The introduction of English in elementary school appears to be an attempt to end the…

The use of remote sensing in mosquito control

NASA Technical Reports Server (NTRS)

1973-01-01

The technology of remote sensing, developed by the space program for identification of surface features from the vantage point of an aircraft or satellite, has substantial application in precisely locating mosquito breeding grounds. Preliminary results of the NASA technology working cooperatively with a city government agency in solving this problem are discussed.

Industrial and Innovation Policy in Europe: The Effects on Growth and Sustainability

ERIC Educational Resources Information Center

Korres, George M.

2007-01-01

Industrial policy is a highly controversial issue. The European Union (EU) justifies its industrial policy on the grounds of common problems across countries, its capacity to coordinate and reduce duplication of efforts, its capacity to control and limit member-state subsidies to industries, and its mandate for foreign trade and competition…

Efficiency of quantum vs. classical annealing in nonconvex learning problems

PubMed Central

Zecchina, Riccardo

2018-01-01

Quantum annealers aim at solving nonconvex optimization problems by exploiting cooperative tunneling effects to escape local minima. The underlying idea consists of designing a classical energy function whose ground states are the sought optimal solutions of the original optimization problem and add a controllable quantum transverse field to generate tunneling processes. A key challenge is to identify classes of nonconvex optimization problems for which quantum annealing remains efficient while thermal annealing fails. We show that this happens for a wide class of problems which are central to machine learning. Their energy landscapes are dominated by local minima that cause exponential slowdown of classical thermal annealers while simulated quantum annealing converges efficiently to rare dense regions of optimal solutions. PMID:29382764

Intelligent (Autonomous) Power Controller Development for Human Deep Space Exploration

NASA Technical Reports Server (NTRS)

Soeder, James; Raitano, Paul; McNelis, Anne

2016-01-01

As NASAs Evolvable Mars Campaign and other exploration initiatives continue to mature they have identified the need for more autonomous operations of the power system. For current human space operations such as the International Space Station, the paradigm is to perform the planning, operation and fault diagnosis from the ground. However, the dual problems of communication lag as well as limited communication bandwidth beyond GEO synchronous orbit, underscore the need to change the operation methodology for human operation in deep space. To address this need, for the past several years the Glenn Research Center has had an effort to develop an autonomous power controller for human deep space vehicles. This presentation discusses the present roadmap for deep space exploration along with a description of conceptual power system architecture for exploration modules. It then contrasts the present ground centric control and management architecture with limited autonomy on-board the spacecraft with an advanced autonomous power control system that features ground based monitoring with a spacecraft mission manager with autonomous control of all core systems, including power. It then presents a functional breakdown of the autonomous power control system and examines its operation in both normal and fault modes. Finally, it discusses progress made in the development of a real-time power system model and how it is being used to evaluate the performance of the controller and well as using it for verification of the overall operation.

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.

The Propulsive-Only Flight Control Problem

NASA Technical Reports Server (NTRS)

Blezad, Daniel J.

1996-01-01

Attitude control of aircraft using only the throttles is investigated. The long time constants of both the engines and of the aircraft dynamics, together with the coupling between longitudinal and lateral aircraft modes make piloted flight with failed control surfaces hazardous, especially when attempting to land. This research documents the results of in-flight operation using simulated failed flight controls and ground simulations of piloted propulsive-only control to touchdown. Augmentation control laws to assist the pilot are described using both optimal control and classical feedback methods. Piloted simulation using augmentation shows that simple and effective augmented control can be achieved in a wide variety of failed configurations.

BEARS: a multi-mission anomaly response system

NASA Astrophysics Data System (ADS)

Roberts, Bryce A.

2009-05-01

The Mission Operations Group at UC Berkeley's Space Sciences Laboratory operates a highly automated ground station and presently a fleet of seven satellites, each with its own associated command and control console. However, the requirement for prompt anomaly detection and resolution is shared commonly between the ground segment and all spacecraft. The efficient, low-cost operation and "lights-out" staffing of the Mission Operations Group requires that controllers and engineers be notified of spacecraft and ground system problems around the clock. The Berkeley Emergency Anomaly and Response System (BEARS) is an in-house developed web- and paging-based software system that meets this need. BEARS was developed as a replacement for an existing emergency reporting software system that was too closedsource, platform-specific, expensive, and antiquated to expand or maintain. To avoid these limitations, the new system design leverages cross-platform, open-source software products such as MySQL, PHP, and Qt. Anomaly notifications and responses make use of the two-way paging capabilities of modern smart phones.

Computational analysis of aerodynamic characteristics for wing in ground effect craft in lateral stability

NASA Astrophysics Data System (ADS)

Amir, M. A. U.; Maimun, A.; Mat, S.; Saad, M. R.

2016-10-01

Wing in-ground effect (WIG) crafts are becoming promising transportation over the last decade. However, stability and control problems faced by the WIG in earlier development are still unresolved. This paper objectively investigates the lateral stability of wing in ground effect craft. The wing encompasses a winglet at the end of the wingtip. Lift, drag and pressure were measured with the respect of the heeling angle of 100, 150 and 200, respectively, with the h/c of 0.3. Initial results from the computational studies show that the ground effect pressure distributions provide a natural righting moment when the WIG craft heels near ground. This initial result provides an insight to understand the current state of knowledge of stability for WIG, particularly on transverse or lateral stability of WIG where it plays important roles in the safety aspect. It is crucial to understand the stability and its component in order to avoid any unforeseen accident. This paper discusses the results obtained from the numerical studies.

Ground-water contamination and legal controls in Michigan

USGS Publications Warehouse

Deutsch, Morris

1963-01-01

The great importance of the fresh ground-water resources of Michigan is evident because 90 percent of the rural and about 70 percent of the total population of the State exclusive of the Detroit metropolitan area are supplied from underground sources. The water-supply and public-health problems that have been caused by some cases of ground-water contamination in the State illustrate the necessity of protecting this vital resource.Manmade and natural contaminants, including many types of chemical and organic matter, have entered many of the numerous aquifers of the State. Aquifers have been contaminated by waste-laden liquids percolating from the surface or from the zone of aeration and by direct injection to the aquifer itself. Industrial and domestic wastes, septic tanks, leaking sewers, flood waters or other poor quality surface waters, mine waters, solids stored or spread at the surface, and even airborne wastes all have been sources of ground-water contamination in Michigan. In addition, naturally occurring saline waters have been induced into other aquifers by overpumping or unrestricted flow from artesian wells, possibly by dewatering operations, and by the deepening of surface stream channels. Vertical migration of saline waters through open holes from formations underlying various important aquifers also has spoiled some of the fresh ground waters in the State. In spite of the contamination that has occurred, however, the total amount of ground water that has been spoiled is only a small part of the total resource. Neither is the contamination so widespread as that of the surface streams of Michigan.Overall legal authority to control most types of ground-water contamination in the State has been assigned by the Michigan Legislature to the Water Resources Commission, although the Department of Conservation and the Health Department also exercise important water-pollution control functions. The Michigan Supreme Court, in an important case upholding the power of the Water Resources Commission to control pollution of ground water, in effect has introduced the doctrine of reasonable use into the law of the State. Excluding controls administered by the Department of Conservation on activities of the oil and gas industry, however, legal controls have not been used abate intrusion of natural saline waters into fresh-water aquifers in response to pumping and other manmade changes in the hydrologic regimen.

Around Marshall

NASA Image and Video Library

1990-12-03

The primary objective of the STS-35 mission was round the clock observation of the celestial sphere in ultraviolet and X-Ray astronomy with the Astro-1 observatory which consisted of four telescopes: the Hopkins Ultraviolet Telescope (HUT); the Wisconsin Ultraviolet Photo-Polarimeter Experiment (WUPPE); the Ultraviolet Imaging Telescope (UIT); and the Broad Band X-Ray Telescope (BBXRT). The Huntsville Operations Support Center (HOSC) Spacelab Payload Operations Control Center (SL POCC) at the Marshall Space Flight Center (MSFC) was the air/ground communication channel used between the astronauts and ground control teams during the Spacelab missions. Teams of controllers and researchers directed on-orbit science operations, sent commands to the spacecraft, received data from experiments aboard the Space Shuttle, adjusted mission schedules to take advantage of unexpected science opportunities or unexpected results, and worked with crew members to resolve problems with their experiments. Pictured is Jack Jones in the Mission Manager Area.

Around Marshall

NASA Image and Video Library

1990-12-07

The primary objective of the STS-35 mission was round the clock observation of the celestial sphere in ultraviolet and X-Ray astronomy with the Astro-1 observatory which consisted of four telescopes: the Hopkins Ultraviolet Telescope (HUT); the Wisconsin Ultraviolet Photo-Polarimeter Experiment (WUPPE); the Ultraviolet Imaging Telescope (UIT); and the Broad Band X-Ray Telescope (BBXRT). The Huntsville Operations Support Center (HOSC) Spacelab Payload Operations Control Center (SL POCC) at the Marshall Space Flight Center (MSFC) was the air/ground communication channel used between the astronauts and ground control teams during the Spacelab missions. Teams of controllers and researchers directed on-orbit science operations, sent commands to the spacecraft, received data from experiments aboard the Space Shuttle, adjusted mission schedules to take advantage of unexpected science opportunities or unexpected results, and worked with crew members to resolve problems with their experiments. This photo is of Space classroom students in the Discovery Optics Lab at MSFC during STS-35, ASTRO-1 mission payload operations.

Around Marshall

NASA Image and Video Library

1990-12-03

The primary objective of the STS-35 mission was round the clock observation of the celestial sphere in ultraviolet and X-Ray astronomy with the Astro-1 observatory which consisted of four telescopes: the Hopkins Ultraviolet Telescope (HUT); the Wisconsin Ultraviolet Photo-Polarimeter Experiment (WUPPE); the Ultraviolet Imaging Telescope (UIT); and the Broad Band X-Ray Telescope (BBXRT). The Huntsville Operations Support Center (HOSC) Spacelab Payload Operations Control Center (SL POCC) at the Marshall Space Flight Center (MSFC) was the air/ground communication channel used between the astronauts and ground control teams during the Spacelab missions. Teams of controllers and researchers directed on-orbit science operations, sent commands to the spacecraft, received data from experiments aboard the Space Shuttle, adjusted mission schedules to take advantage of unexpected science opportunities or unexpected results, and worked with crew members to resolve problems with their experiments. Pictured is the TV OPS area of the SL POCC.

Optimal Path Planning and Control of Quadrotor Unmanned Aerial Vehicle for Area Coverage

NASA Astrophysics Data System (ADS)

Fan, Jiankun

An Unmanned Aerial Vehicle (UAV) is an aircraft without a human pilot on board. Its flight is controlled either autonomously by computers onboard the vehicle, or remotely by a pilot on the ground, or by another vehicle. In recent years, UAVs have been used more commonly than prior years. The example includes areo-camera where a high speed camera was attached to a UAV which can be used as an airborne camera to obtain aerial video. It also could be used for detecting events on ground for tasks such as surveillance and monitoring which is a common task during wars. Similarly UAVs can be used for relaying communication signal during scenarios when regular communication infrastructure is destroyed. The objective of this thesis is motivated from such civilian operations such as search and rescue or wildfire detection and monitoring. One scenario is that of search and rescue where UAV's objective is to geo-locate a person in a given area. The task is carried out with the help of a camera whose live feed is provided to search and rescue personnel. For this objective, the UAV needs to carry out scanning of the entire area in the shortest time. The aim of this thesis to develop algorithms to enable a UAV to scan an area in optimal time, a problem referred to as "Coverage Control" in literature. The thesis focuses on a special kind of UAVs called "quadrotor" that is propelled with the help of four rotors. The overall objective of this thesis is achieved via solving two problems. The first problem is to develop a dynamic control model of quadrtor. In this thesis, a proportional-integral-derivative controller (PID) based feedback control system is developed and implemented on MATLAB's Simulink. The PID controller helps track any given trajectory. The second problem is to design a trajectory that will fulfill the mission. The planed trajectory should make sure the quadrotor will scan the whole area without missing any part to make sure that the quadrotor will find the lost person in the area. The generated trajectory should also be optimal. This is achieved via making some assumptions on the form of the trajectory and solving the optimization problem to obtain optimal parameters of the trajectory. The proposed techniques are validated with the help of numerous simulations.

Measuring software development characteristics in the local environment. [considering project requirements for spacecraft control

NASA Technical Reports Server (NTRS)

Basili, V. R.; Zelkowitz, M. V.

1978-01-01

In a brief evaluation of software-related considerations, it is found that suitable approaches for software development depend to a large degree on the characteristics of the particular project involved. An analysis is conducted of development problems in an environment in which ground support software is produced for spacecraft control. The amount of work involved is in the range from 6 to 10 man-years. Attention is given to a general project summary, a programmer/analyst survey, a component summary, a component status report, a resource summary, a change report, a computer program run analysis, aspects of data collection on a smaller scale, progress forecasting, problems of overhead, and error analysis.

Reducing air pollutant emissions at airports by controlling aircraft ground operations

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

Gelinas, C.G.; Fan, H.S.L.

1979-02-01

Average-day carbon monoxide, total hydrocarbon, and NO/sub x/ aircraft emissions and fuel use estimates (apportioned to takeoff, taxi, idle, and landing) for departure and arrival at Los Angeles and San Francisco International Airports were compared with emissions level and fuel use estimates for four emission reduction strategies (tow aircraft between runways and gates, shutdown one engine during taxiing, control departure time, and assign runways to minimize taxiing distance). The best strategy, the shutdown of one engine while taxiing, produces substantial emission reductions, cost benefits owing to fuel savings, and no apparent safety problems; aircraft towing reduced emissions significantly, but introducedmore » a number of safety problems.« less

A mathematical problem and a Spacecraft Control Laboratory Experiment (SCOLE) used to evaluate control laws for flexible spacecraft. NASA/IEEE design challenge

NASA Technical Reports Server (NTRS)

Taylor, Lawrence W., Jr.; Balakrishnan, A. V.

1988-01-01

The problen of controlling large, flexible space systems has been evaluated using computer simulation. In several cases, ground experiments have also been used to validate system performance under more realistic conditions. There remains a need, however, to test additional control laws for flexible spacecraft and to directly compare competing design techniques. A program is discussed which has been initiated to make direct comparisons of control laws for, first, a mathematical problem, then and experimental test article being assembled under the cognizance of the Spacecraft Control Branch at the NASA Langley Research Center with the advice and counsel of the IEEE Subcommittee on Large Space Structures. The physical apparatus will consist of a softly supported dynamic model of an antenna attached to the Shuttle by a flexible beam. The control objective will include the task of directing the line-of-sight of the Shuttle antenna configuration toward a fixed target, under conditions of noisy data, control authority and random disturbances.

Safety Control and Safety Education at Technical Institutes

NASA Astrophysics Data System (ADS)

Iino, Hiroshi

The importance of safety education for students at technical institutes is emphasized on three grounds including safety of all working members and students in their education, research and other activities. The Kanazawa Institute of Technology re-organized the safety organization into a line structure and improved safety minds of all their members and now has a chemical materials control system and a set of compulsory safety education programs for their students, although many problems still remain.

A wind-tunnel investigation of parameters affecting helicopter directional control at low speeds in ground effect

NASA Technical Reports Server (NTRS)

Yeager, W. T., Jr.; Young, W. H., Jr.; Mantay, W. R.

1974-01-01

An investigation was conducted in the Langley full-scale tunnel to measure the performance of several helicopter tail-rotor/fin configurations with regard to directional control problems encountered at low speeds in ground effect. Tests were conducted at wind azimuths of 0 deg to 360 deg in increments of 30 deg and 60 deg and at wind speeds from 0 to 35 knots. The results indicate that at certain combinations of wind speed and wind azimuth, large increases in adverse fin force require correspondingly large increases in the tail-rotor thrust, collective pitch, and power required to maintain yaw trim. Changing the tail-rotor direction of rotation to top blade aft for either a pusher tail rotor (tail-rotor wake blowing away from fin) or a tractor tail rotor (tail-rotor wake blowing against fin) will alleviate this problem. For a pusher tail rotor at 180 deg wind azimuth, increases in the fin/tail-rotor gap were not found to have any significant influence on the overall vehicle directional control capability. Changing the tail rotor to a higher position was found to improve tail-rotor performance for a fin-off configuration at a wind azimuth of 180 deg. A V-tail configuration with a pusher tail rotor with top blade aft direction of rotation was found to be the best configuration with regard to overall directional control capability.

Lessons learned from Shuttle/Mir: psychosocial countermeasures

NASA Technical Reports Server (NTRS)

Kanas, Nick; Salnitskiy, Vyacheslav; Grund, Ellen M.; Gushin, Vadim; Weiss, Daniel S.; Kozerenko, Olga; Sled, Alexander; Marmar, Charles R.

2002-01-01

BACKGROUND: During future long-duration space missions, countermeasures need to be developed to deal with psychosocial issues that might impact negatively on crewmember performance and well-being. METHODS: In our recently completed NASA-funded study of 5 U.S. astronauts, 8 Russian cosmonauts, and 42 U.S. and 16 Russian mission control personnel who participated in the Shuttle/Mir program, we evaluated a number of important psychosocial issues such as group tension, cohesion, leadership role, and the displacement of negative emotions from crewmembers to people in mission control and from mission control personnel to management. RESULTS: Based on our findings, which are reviewed, a number of psychosocial countermeasures are suggested to help ameliorate the negative impact of potential psychosocial problems during future manned space missions. CONCLUSIONS: Crewmembers should be selected not only to rule out psychopathology but also to select-in for group compatibility and facility in a common language. Training should include briefings and team building related to a number of psychosocial issues and should involve both crewmembers and mission control personnel. During the mission, both experts on the ground and the crewmembers themselves should be alert to potential interpersonal problems, including the displacement of negative emotions from the crew to the ground. Supportive activities should consist of both individual and interpersonal strategies, including an awareness of changing leisure time needs. Finally, attention should be given to postmission readjustment and to supporting the families on Earth.

Operation Anaconda: Lessons Learned, or Lessons Observed?

DTIC Science & Technology

2009-06-12

commentators have noted that suboptimal command and control relationships, lack of communication , and confusion all contributed to the initial...lack of communication , and confusion all contributed to the initial problems in air/ground coordination, few have examined the joint and service...continuous challenge in modern warfare. Despite the vast increases in communications and information sharing capabilities that have accompanied

Concerns in Water Supply and Pollution Control: Legal, Social, and Economic.

ERIC Educational Resources Information Center

Burke, D. Barlow, Jr.; And Others

This bulletin contains three articles which focus on ground water's potential as a dependable supply source and some of the problems impeding the development of that potential. The authors' concerns are discussed from the vantage point of their areas of specialization: law, sociology, and economics. The first author states that water law abounds…

World Population: U.N. on the Move but Grounds for Optimism Are Scant

ERIC Educational Resources Information Center

Holden, Constance

1974-01-01

Discusses current trends and problems relating to world population, and focuses on action being taken by the United Nations. This year (1974) has been designated World Population Year, and will be highlighted by a conference in Bucharest in which all 130 member governments will meet to confront the issue of population control. (JR)

Computation of Ground-State Properties in Molecular Systems: Back-Propagation with Auxiliary-Field Quantum Monte Carlo.

PubMed

Motta, Mario; Zhang, Shiwei

2017-11-14

We address the computation of ground-state properties of chemical systems and realistic materials within the auxiliary-field quantum Monte Carlo method. The phase constraint to control the Fermion phase problem requires the random walks in Slater determinant space to be open-ended with branching. This in turn makes it necessary to use back-propagation (BP) to compute averages and correlation functions of operators that do not commute with the Hamiltonian. Several BP schemes are investigated, and their optimization with respect to the phaseless constraint is considered. We propose a modified BP method for the computation of observables in electronic systems, discuss its numerical stability and computational complexity, and assess its performance by computing ground-state properties in several molecular systems, including small organic molecules.

Configuration management and software measurement in the Ground Systems Development Environment (GSDE)

NASA Technical Reports Server (NTRS)

Church, Victor E.; Long, D.; Hartenstein, Ray; Perez-Davila, Alfredo

1992-01-01

A set of functional requirements for software configuration management (CM) and metrics reporting for Space Station Freedom ground systems software are described. This report is one of a series from a study of the interfaces among the Ground Systems Development Environment (GSDE), the development systems for the Space Station Training Facility (SSTF) and the Space Station Control Center (SSCC), and the target systems for SSCC and SSTF. The focus is on the CM of the software following delivery to NASA and on the software metrics that relate to the quality and maintainability of the delivered software. The CM and metrics requirements address specific problems that occur in large-scale software development. Mechanisms to assist in the continuing improvement of mission operations software development are described.

Ground-state properties of the three-band Hubbard model

NASA Astrophysics Data System (ADS)

Zhang, Shiwei; Vitali, Ettore; Chiciak, Adam; Shi, Hao

The three-band Hubbard model proposed by Emery describes the CuO2 plane in cuprate superconductors by retaining both Cu and O orbitals in a minimal sense. Applying the latest developments in the auxiliary-field quantum Monte Carlo (AFQMC) method, we investigate ground-state properties of this model at half-filling and when lightly (under-)doped. The AFQMC uses generalized Hartree-Fock (GHF) trial wave functions to control the sign problem. A self-consistent constraint is applied. We also determine the unrestricted Hartree-Fock (UHF) and GHF ground states and compare their predictions with those from AFQMC. Similarities and differences between the three-band model and one-band Hubbard model will be discussed. Supported by NSF, and the Simons Foundation. Computing is carried out at the Extreme Science and Engineering Discovery Environment(XSEDE).

Development and evaluation of automatic landing control laws for power lift STOL aircraft

NASA Technical Reports Server (NTRS)

Feinreich, B.; Gevaert, G.

1981-01-01

A series of investigations were conducted to generate and verify through ground bases simulation and flight research a data base to aid in the design and certification of advanced propulsive lift short takeoff and landing aircraft. Problems impacting the design of powered lift short haul aircraft that are to be landed automatically on STOL runways in adverse weather were examined. An understanding of the problems was gained by a limited coverage of important elements that are normally included in the certification process of a CAT 3 automatic landing system.

Common approach to solving SGEMP, DEMP, and ESD survivability

NASA Technical Reports Server (NTRS)

Ling, D.

1977-01-01

System Generated Electromagnetic Pulse (SGEMP) and Dispersed Electromagnetic Pulse DEMP) are nuclear generated spacecraft environments. Electrostatic discharge (ESD) is a natural spacecraft environment resulting from differential charging in magnetic substorms. All three phenomena, though differing in origin, result in the same problem to the spacecraft and that is Electromagnetic Interference (EMI). A common design approach utilizing a spacecraft structural Faraday Cage is presented which helps solve the EMI problem. Also, other system design techniques are discussed which minimize the magnitude of these environments through control of materials and electrical grounding configuration.

Study on the technology of dual-tube layered injection in ASP flooding

NASA Astrophysics Data System (ADS)

Yang, Ye; Zhang, Yongping; Xu, Dekui; Cai, Meng; Yang, Zhigang; Wang, Hailong; Song, Xingliang

2017-10-01

For the single-tube layered injection technology cannot solve the problem of interlayer pressure difference is greater than 2MPa injection wells, through the development of dual-tube packer, dual-tube injection allocator, downhole plug, the ground pressure regulator and molecular weight regulator. Dual-tube layered injection technology is formed. According to the data of ASP flooding injection wells in the field, the whole well is divided into high permeability and low permeability oil reservoir. Two separate injection channels can be formed by using dual-tube packer and dual-tube injection allocator. Through the use of the ground pressure regulator, the problem of the high permeability layer and low permeability layer of the injection pressure difference is solved. Through the use of the ground molecular weight regulator, the problem that the same molecular weight ASP solution is not suitable for high and low permeability is solved. By replacing the downhole plug, the grouping transformation of some oil layer can be achieved. The experiment and field application of 3 wells results show that: the flow control range is 20m3/d-70m3/d; the max. Throttling differential pressure is 3.5MPa; the viscosity loss rate of solution is less than 5%; and the molecular weight adjusting range is 20%-50%. The utilization degree of oil layer is obviously increased through the use of the dual-tube layered injection technology.

Pumping strategies for management of a shallow water table: The value of the simulation-optimization approach

USGS Publications Warehouse

Barlow, P.M.; Wagner, B.J.; Belitz, K.

1996-01-01

The simulation-optimization approach is used to identify ground-water pumping strategies for control of the shallow water table in the western San Joaquin Valley, California, where shallow ground water threatens continued agricultural productivity. The approach combines the use of ground-water flow simulation with optimization techniques to build on and refine pumping strategies identified in previous research that used flow simulation alone. Use of the combined simulation-optimization model resulted in a 20 percent reduction in the area subject to a shallow water table over that identified by use of the simulation model alone. The simulation-optimization model identifies increasingly more effective pumping strategies for control of the water table as the complexity of the problem increases; that is, as the number of subareas in which pumping is to be managed increases, the simulation-optimization model is better able to discriminate areally among subareas to determine optimal pumping locations. The simulation-optimization approach provides an improved understanding of controls on the ground-water flow system and management alternatives that can be implemented in the valley. In particular, results of the simulation-optimization model indicate that optimal pumping strategies are constrained by the existing distribution of wells between the semiconfined and confined zones of the aquifer, by the distribution of sediment types (and associated hydraulic conductivities) in the western valley, and by the historical distribution of pumping throughout the western valley.

STS-35 Mission Manager Actions Room at the Marshall Space Flight Center Spacelab Payload Operations

NASA Technical Reports Server (NTRS)

1990-01-01

The primary objective of the STS-35 mission was round the clock observation of the celestial sphere in ultraviolet and X-Ray astronomy with the Astro-1 observatory which consisted of four telescopes: the Hopkins Ultraviolet Telescope (HUT); the Wisconsin Ultraviolet Photo-Polarimeter Experiment (WUPPE); the Ultraviolet Imaging Telescope (UIT); and the Broad Band X-Ray Telescope (BBXRT). The Huntsville Operations Support Center (HOSC) Spacelab Payload Operations Control Center (SL POCC) at the Marshall Space Flight Center (MSFC) was the air/ground communication channel used between the astronauts and ground control teams during the Spacelab missions. Teams of controllers and researchers directed on-orbit science operations, sent commands to the spacecraft, received data from experiments aboard the Space Shuttle, adjusted mission schedules to take advantage of unexpected science opportunities or unexpected results, and worked with crew members to resolve problems with their experiments. Due to loss of data used for pointing and operating the ultraviolet telescopes, MSFC ground teams were forced to aim the telescopes with fine tuning by the flight crew. This photo captures the activities at the Mission Manager Actions Room during the mission.

HUT Data Inspected at Marshall Space Flight Center During the STS-35 Mission

NASA Technical Reports Server (NTRS)

1990-01-01

The primary objective of the STS-35 mission was round the clock observation of the celestial sphere in ultraviolet and X-Ray astronomy with the Astro-1 observatory which consisted of four telescopes: the Hopkins Ultraviolet Telescope (HUT); the Wisconsin Ultraviolet Photo-Polarimeter Experiment (WUPPE); the Ultraviolet Imaging Telescope (UIT); and the Broad Band X-Ray Telescope (BBXRT). The Huntsville Operations Support Center (HOSC) Spacelab Payload Operations Control Center (SL POCC) at the Marshall Space Flight Center (MSFC) was the air/ground communication channel used between the astronauts and ground control teams during the Spacelab missions. Teams of controllers and researchers directed on-orbit science operations, sent commands to the spacecraft, received data from experiments aboard the Space Shuttle, adjusted mission schedules to take advantage of unexpected science opportunities or unexpected results, and worked with crew members to resolve problems with their experiments. Due to loss of data used for pointing and operating the ultraviolet telescopes, MSFC ground teams were forced to aim the telescopes with fine tuning by the flight crew. This photo captures the activity of viewing HUT data in the Mission Manager Actions Room during the mission.

A precise time synchronization method for 5G based on radio-over-fiber network with SDN controller

NASA Astrophysics Data System (ADS)

He, Linkuan; Wei, Baoguo; Yang, Hui; Yu, Ao; Wang, Zhengyong; Zhang, Jie

2018-02-01

There is an increasing demand on accurate time synchronization with the growing bandwidth of network service for 5G. In 5G network, it's necessary for base station to achieve accurate time synchronization to guarantee the quality of communication. In order to keep accuracy time for 5G network, we propose a time synchronization system for satellite ground station based on radio-over-fiber network (RoFN) with software defined optical network (SDON) controller. The advantage of this method is to improve the accuracy of time synchronization of ground station. The IEEE 1588 time synchronization protocol can solve the problems of high cost and lack of precision. However, in the process of time synchronization, distortion exists during the transmission of digital time signal. RoF uses analog optical transmission links and therefore analog transmission can be implemented among ground stations instead of digital transmission, which means distortion and bandwidth waste in the process of digital synchronization can be avoided. Additionally, the thought of SDN, software defined network, can optimize RoFN with centralized control and simplifying base station. Related simulation had been carried out to prove its superiority.

Multimodel methods for optimal control of aeroacoustics.

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

Chen, Guoquan; Collis, Samuel Scott

2005-01-01

A new multidomain/multiphysics computational framework for optimal control of aeroacoustic noise has been developed based on a near-field compressible Navier-Stokes solver coupled with a far-field linearized Euler solver both based on a discontinuous Galerkin formulation. In this approach, the coupling of near- and far-field domains is achieved by weakly enforcing continuity of normal fluxes across a coupling surface that encloses all nonlinearities and noise sources. For optimal control, gradient information is obtained by the solution of an appropriate adjoint problem that involves the propagation of adjoint information from the far-field to the near-field. This computational framework has been successfully appliedmore » to study optimal boundary-control of blade-vortex interaction, which is a significant noise source for helicopters on approach to landing. In the model-problem presented here, the noise propagated toward the ground is reduced by 12dB.« less

Spacecraft Dynamics and Control Program at AFRPL

NASA Technical Reports Server (NTRS)

Das, A.; Slimak, L. K. S.; Schloegel, W. T.

1986-01-01

A number of future DOD and NASA spacecraft such as the space based radar will be not only an order of magnitude larger in dimension than the current spacecraft, but will exhibit extreme structural flexibility with very low structural vibration frequencies. Another class of spacecraft (such as the space defense platforms) will combine large physical size with extremely precise pointing requirement. Such problems require a total departure from the traditional methods of modeling and control system design of spacecraft where structural flexibility is treated as a secondary effect. With these problems in mind, the Air Force Rocket Propulsion Laboratory (AFRPL) initiated research to develop dynamics and control technology so as to enable the future large space structures (LSS). AFRPL's effort in this area can be subdivided into the following three overlapping areas: (1) ground experiments, (2) spacecraft modeling and control, and (3) sensors and actuators. Both the in-house and contractual efforts of the AFRPL in LSS are summarized.

CONFRONTING THE MODIFIABLE AREAL UNIT PROBLEM FOR INFERENCE ON NITRATE IN REGIONAL SHALLOW GROUND WATER

EPA Science Inventory

This work addresses a potentially serious problem in synthesis of
spatially explicit data on ground water quality from wells, known to
geographers as the modifiable areal unit problem (MAUP). Investigators
are faced with choosing a level of aggregation appropriate to
...

Remote sensing and disease control in China: past, present and future

PubMed Central

2013-01-01

Satellite measurements have distinct advantages over conventional ground measurements because they can collect the information repeatedly and automatically. Since 1970 globally and 1985 in China, the availability of remote sensing (RS) techniques has steadily grown and they are becoming increasingly important to improve our understanding of human health. This paper gives the first detailed overview on the developments of RS applications for disease control in China. The problems, challenges and future directions are also discussed with an aim of guiding prospective studies. PMID:23311958

A survey of new technology for cockpit application to 1990's transport aircraft simulators

NASA Technical Reports Server (NTRS)

Holt, A. P., Jr.; Noneaker, D. O.; Walthour, L.

1980-01-01

Two problems were investigated: inter-equipment data transfer, both on board the aircraft and between air and ground; and crew equipment communication via the cockpit displays and controls. Inter-equipment data transfer is discussed in terms of data bus and data link requirements. Crew equipment communication is discussed regarding the availability of CRT display systems for use in research simulators to represent flat panel displays of the future, and of software controllable touch panels.

Trained sensory panel and consumer evaluation of the effects of gamma irradiation on palatability of vacuum-packaged frozen ground beef patties.

PubMed

Wheeler, T L; Shackelford, S D; Koohmaraie, M

1999-12-01

The objectives for this experiment were to determine the effects of gamma irradiation on 1) the palatability of vacuum-packaged frozen ground beef patties by trained sensory panel and 2) consumer evaluation of the taste of hamburgers made with those patties. Boxes (4.5 kg) of frozen (-28 degrees C) ground beef patties (113.4 g/patty, 19% fat) from a commercial supplier were irradiated at a commercial gamma irradiation facility at one of three levels (0, 3.0, or 4.5 kGy). All boxes were stored at 28 degrees C for 27 to 29 d after irradiation before evaluation by a trained descriptive attribute sensory panel and for 62 to 104 d after irradiation before consumer evaluation. The trained panel evaluated grilled patties for ground beef aroma intensity, off-aroma, and off-flavor on 4-point scales (4 = intense, none, and none; 1 = none, intense, and intense, respectively) and ground beef flavor intensity, tenderness, and juiciness on 8-point scales (8 = extremely intense, tender, or juicy; 1 = extremely bland, tough, or dry). Control patties had more intense (P<.05) ground beef aroma (3.1 vs 2.6), less off-aroma (3.3 vs 2.6), and more intense ground beef flavor (4.9 vs. 4.3) than irradiated patties. However, there were no differences (P>.05) in any sensory trait between frozen ground beef patties treated with 3.0 or 4.5 kGy of gamma irradiation. There were no differences (P>.05) among treatments for tenderness (6.3, 6.6, and 6.7) or juiciness ratings (5.7, 5.9, and 5.9), respectively, for 0, 3.0, and 4.5 kGy. The consumers evaluated taste of a hamburger that included their choice of condiments on a 10-point scale (10 = excellent; 1 = terrible). Hamburgers made with patties treated with 4.5 kGy were rated lower (P<.05) in taste than hamburgers made with either control patties or those treated with 3.0 kGy (6.5, 6.6, and 6.2, respectively, for 0, 3.0, and 4.5 kGy); however, all doses were rated at some level of "fair." These results imply that hamburgers made from ground beef patties irradiated under the conditions of this experiment would encounter little, if any, consumer acceptance problems at the 3.0 kGy dose and only slightly greater problems at the 4.5 kGy dose.

A randomized controlled trial of Moderation-Oriented Cue Exposure.

PubMed

Heather, N; Brodie, J; Wale, S; Wilkinson, G; Luce, A; Webb, E; McCarthy, S

2000-07-01

A randomized controlled trial was conducted to examine the effectiveness of Moderation-Oriented Cue Exposure (MOCE) in comparison to Behavioral Self-Control Training (BSCT). The main hypothesis was that MOCE would be more effective than BSCT among a sample of problem drinkers aiming at moderate drinking. A subsidiary hypothesis was that MOCE would be relatively more effective than BSCT among problem drinkers with higher levels of alcohol dependence. Clients (N = 91; 75% men) were randomly allocated to either MOCE or BSCT. Treatment was delivered in weekly sessions by two trained therapists, in a nested design in which therapists switched to the alternative treatment modality approximately halfway through the trial. Follow-up was carried out 6 months following posttreatment assessment, with 85% successful contact. There was no evidence for the general superiority of MOCE over BSCT. The subsidiary hypothesis was not confirmed. A subsample of clients (n = 14) showing levels of dependence at baseline above the commonly accepted cut-point for a moderation goal (Severity of Alcohol Dependence Questionnaire [SADQ] > 29) showed outcomes at least as favorable as those below the cut-point. The validity of self-reports of alcohol consumption and problems was supported by significant relationships with liver function tests (gamma-glutamyl transferase and alanine transferase). These results provide no grounds for the replacement of BSCT by MOCE in routine, moderation-oriented treatment practice. Assuming they prefer it to abstinence and that it is not contra-indicated on other grounds, there seems no reason why clients showing a higher level of dependence (SADQ = 30-45) should not be offered a moderation goal.

Overview of Intelligent Power Controller Development for Human Deep Space Exploration

NASA Technical Reports Server (NTRS)

Soeder, James F.; Dever, Timothy P.; McNelis, Anne M.; Beach, Raymond F.; Trase, Larry M.; May, Ryan D.

2014-01-01

Intelligent or autonomous control of an entire spacecraft is a major technology that must be developed to enable NASA to meet its human exploration goals. NASA's current long term human space platform, the International Space Station, is in low Earth orbit with almost continuous communication with the ground based mission control. This permits the near real-time control by the ground of all of the core systems including power. As NASA moves beyond low Earth orbit, the issues of communication time-lag and lack of communication bandwidth beyond geosynchronous orbit does not permit this type of operation. This paper presents the work currently ongoing at NASA to develop an architecture for an autonomous power control system as well as the effort to assemble that controller into the framework of the vehicle mission manager and other subsystem controllers to enable autonomous control of the complete spacecraft. Due to the common problems faced in both space power systems and terrestrial power system, the potential for spin-off applications of this technology for use in micro-grids located at the edge or user end of terrestrial power grids for peak power accommodation and reliability are described.

Overview of Intelligent Power Controller Development for Human Deep Space Exploration

NASA Technical Reports Server (NTRS)

Soeder, James F.; Dever, Timothy P.; McNelis, Anne M.; Beach, Raymond F.; Trase, Larry M.; May, Ryan D.

2014-01-01

Intelligent or autonomous control of an entire spacecraft is a major technology that must be developed to enable NASA to meet its human exploration goals. NASA's current long term human space platform, the International Space Station, is in low earth orbit with almost continuous communication with the ground based mission control. This permits the near real-time control by the ground of all of the core systems including power. As NASA moves beyond Low Earth Orbit, the issues of communication time-lag and lack of communication bandwidth beyond geosynchronous orbit does not permit this type of operation. This paper presents the work currently ongoing at NASA to develop an architecture for an autonomous power control system as well as the effort to assemble that controller into the framework of the vehicle mission manager and other subsystem controllers to enable autonomous control of the complete spacecraft. Due to the common problems faced in both space power systems and terrestrial power system, the potential for spin-off applications of this technology for use in micro-grids located at the edge or user end of terrestrial power grids for peak power accommodation and reliability are described.

Overview of Intelligent Power Controller Development for Human Deep Space Exploration

NASA Technical Reports Server (NTRS)

Soeder, James F.; Dever, Timothy P.; McNelis, Anne M.; Beach, Raymond F.; Trase, Larry M.; May, Ryan

2014-01-01

Intelligent or autonomous control of an entire spacecraft is a major technology that must be developed to enable NASA to meet its human exploration goals. NASAs current long term human space platform, the International Space Station, is in low earth orbit with almost continuous communication with the ground based mission control. This permits the near real-time control by the ground of all of the core systems including power. As NASA moves beyond Low Earth Orbit, the issues of communication time-lag and lack of communication bandwidth beyond geosynchronous orbit does not permit this type of operation. This paper presents the work currently ongoing at NASA to develop an architecture for an autonomous power control system as well as the effort to assemble that controller into the framework of the vehicle mission manager and other subsystem controllers to enable autonomous control of the complete spacecraft. Due to the common problems faced in both space power systems and terrestrial power system, the potential for spin-off applications of this technology for use in micro-grids located at the edge or user end of terrestrial power grids for peak power accommodation and reliability are described.

Emergency Nursing Experiences in Assisting People With Suicidal Behavior: A Grounded Theory Study.

PubMed

Vedana, Kelly Graziani Giacchero; Magrini, Daniel Fernando; Miasso, Adriana Inocenti; Zanetti, Ana Carolina Guidorizzi; de Souza, Jacqueline; Borges, Tatiana Longo

2017-08-01

To understand emergency nursing experiences in assisting people with suicidal behavior. Grounded theory study with symbolic interactionism conducted in 2015 to 2016 in Brazil with 19 nurses. Assistance for people with suicidal behavior is critical, challenging, evokes different feelings and requires knowledge, skills and emotional control. Nurses did not feel prepared or supported, and identified recurrent gaps and problems. Nurses occupied a limited role, restricted to attending to physical needs. They predominantly manifested opposition, judgments and incomprehension about patients. This study presents key elements to be addressed in interventions and investigations regarding nursing support, training and supervision. Copyright © 2017 Elsevier Inc. All rights reserved.

Ground cross-modal impedance as a tool for analyzing ground/plate interaction and ground wave propagation.

PubMed

Grau, L; Laulagnet, B

2015-05-01

An analytical approach is investigated to model ground-plate interaction based on modal decomposition and the two-dimensional Fourier transform. A finite rectangular plate subjected to flexural vibration is coupled with the ground and modeled with the Kirchhoff hypothesis. A Navier equation represents the stratified ground, assumed infinite in the x- and y-directions and free at the top surface. To obtain an analytical solution, modal decomposition is applied to the structure and a Fourier Transform is applied to the ground. The result is a new tool for analyzing ground-plate interaction to resolve this problem: ground cross-modal impedance. It allows quantifying the added-stiffness, added-mass, and added-damping from the ground to the structure. Similarity with the parallel acoustic problem is highlighted. A comparison between the theory and the experiment shows good matching. Finally, specific cases are investigated, notably the influence of layer depth on plate vibration.

Some wake-related operational limitations of rotorcraft

NASA Technical Reports Server (NTRS)

Heyson, H. H.

1980-01-01

Wind tunnel measurements show that the wake of a rotor, except at near hovering speeds, is not like that of a propeller. The wake is more like that of a wing except that, because of the slow speeds, the wake velocities may be much greater. The helicopter can produce a wake hazard to following light aircraft that is disproportionately great compared to an equivalent fixed wing aircraft. This hazard should be recognized by both pilots and airport controllers when operating in congested areas. Ground effect is generally counted as a blessing since it allows overloaded takeoffs; however, it also introduces additional operation problems. These problems include premature blade stall in hover, settling in forward transition, shuddering in approach to touchdown and complicatons with yaw control. Some of these problems were treated analytically in an approximate manner and reasonable experiment agreement was obtained. An awareness of these effects can prepare the user for their appearance and their consequences.

Quantum annealing for the number-partitioning problem using a tunable spin glass of ions

PubMed Central

Graß, Tobias; Raventós, David; Juliá-Díaz, Bruno; Gogolin, Christian; Lewenstein, Maciej

2016-01-01

Exploiting quantum properties to outperform classical ways of information processing is an outstanding goal of modern physics. A promising route is quantum simulation, which aims at implementing relevant and computationally hard problems in controllable quantum systems. Here we demonstrate that in a trapped ion setup, with present day technology, it is possible to realize a spin model of the Mattis-type that exhibits spin glass phases. Our method produces the glassy behaviour without the need for any disorder potential, just by controlling the detuning of the spin-phonon coupling. Applying a transverse field, the system can be used to benchmark quantum annealing strategies which aim at reaching the ground state of the spin glass starting from the paramagnetic phase. In the vicinity of a phonon resonance, the problem maps onto number partitioning, and instances which are difficult to address classically can be implemented. PMID:27230802

Optimal tactics for close support operations. III - Degraded intelligence and communications

NASA Astrophysics Data System (ADS)

Hess, J.; Kalaba, R.; Kagiwada, H.; Spingarn, K.; Tsokos, C.

1980-04-01

A new generation of C3 (command, control, and communication) models for military cybernetics is developed. Recursive equations for the solution of the C3 problem are derived for an amphibious campaign with linear time-varying dynamics. Air and ground commanders are assumed to have no intelligence and no communications. Numerical results are given for the optimal decision rules.

Civil Aviation Research and Development /CARD/ Policy Study.

NASA Technical Reports Server (NTRS)

Syvertson, C. A.

1971-01-01

The results of the study lead to a number of conclusions regarding priority areas for R and D. It was found that aircraft noise abatement deserves highest priority because of widespread concern for the environment and because the success of the noise-abatement program will affect the solutions to other problems. Congestion is next on the list of priority problems. Its solution will involve an organized effort directed at the combination of air traffic control, runway capacity, ground control of aircraft, terminal processing, access and egress, parking, and airport location, acquisition, and development. A new short-haul system could help relieve congestion at existing airports. Constant improvements in technology for long-haul vehicles and their propulsion systems are essential to continued U.S. leadership.

Pharmacology in space. Part 2. Controlling motion sickness

NASA Technical Reports Server (NTRS)

Lathers, C. M.; Charles, J. B.; Bungo, M. W.

1989-01-01

In this second article in the two-part series on pharmacology in space, Claire Lathers and colleagues discuss the pharmacology of drugs used to control motion sickness in space and note that the pharmacology of the 'ideal' agent has yet to be worked out. That motion sickness may impair the pharmacological action of a drug by interfering with its absorption and distribution because of alteration of physiology is a problem unique to pharmacology in space. The authors comment on the problem of designing suitable ground-based studies to evaluate the pharmacological effect of drugs to be used in space and discuss the use of salivary samples collected during space flight to allow pharmacokinetic evaluations necessary for non-invasive clinical drug monitoring.

Stochastic correlative firing for figure-ground segregation.

PubMed

Chen, Zhe

2005-03-01

Segregation of sensory inputs into separate objects is a central aspect of perception and arises in all sensory modalities. The figure-ground segregation problem requires identifying an object of interest in a complex scene, in many cases given binaural auditory or binocular visual observations. The computations required for visual and auditory figure-ground segregation share many common features and can be cast within a unified framework. Sensory perception can be viewed as a problem of optimizing information transmission. Here we suggest a stochastic correlative firing mechanism and an associative learning rule for figure-ground segregation in several classic sensory perception tasks, including the cocktail party problem in binaural hearing, binocular fusion of stereo images, and Gestalt grouping in motion perception.

Review of Leading Approaches for Mitigating Hypersonic Vehicle Communications Blackout and a Method of Ceramic Particulate Injection Via Cathode Spot Arcs for Blackout Mitigation

NASA Technical Reports Server (NTRS)

Gillman, Eric D.; Foster, John E.; Blankson, Isaiah M.

2010-01-01

Vehicles flying at hypersonic velocities within the atmosphere become enveloped in a "plasma sheath" that prevents radio communication, telemetry, and most importantly, GPS signal reception for navigation. This radio "blackout" period has been a problem since the dawn of the manned space program and was an especially significant hindrance during the days of the Apollo missions. An appropriate mitigation method must allow for spacecraft to ground control and ground control to spacecraft communications through the reentry plasma sheath. Many mitigation techniques have been proposed, including but not limited to, aerodynamic shaping, magnetic windows, and liquid injection. The research performed on these mitigation techniques over the years will be reviewed and summarized, along with the advantages and obstacles that each technique will need to overcome to be practically implemented. A unique approach for mitigating the blackout communications problem is presented herein along with research results associated with this method. The novel method involves the injection of ceramic metal-oxide particulate into a simulated reentry plasma to quench the reentry plasma. Injection of the solid ceramic particulates is achieved by entrainment within induced, energetic cathode spot flows.

Engineering management consideration for an integrated aeronautical mobile satellite service

NASA Astrophysics Data System (ADS)

Belcher, John M.

In order to meet local air traffic control terminal requirements as well as national and transborder requirements, countries have developed communications, navigation, and surveillance (CNS) systems having little systems integration and a solely ground-based solution to air traffic control problems. It is believed that the application of satellite technology is the only currently viable solution that will enable international civil aviation to overcome the shortcomings of the presently available CNS systems. If properly implemented, available satellite system technology integrated with avionics and ground based capabilities, can be used to meet new global aviation demands. A clear transition plan has to be implemented so as to ensure continuity of service, recognize user-borne costs, and satisfy institutional and national objectives in the progress toward a universal air traffic management (ATM) system. ATM systems design should rely on a modular approach for flexibility and upgrading. An aeronautical mobile satellite service is intended to provide a worldwide satellite data link and direct air/ground voice communication. Institutional and financial roadblocks for implemetation of a global based approach will likely be far greater than technical constraints.

Experiments in structural dynamics and control using a grid

NASA Technical Reports Server (NTRS)

Montgomery, R. C.

1985-01-01

Future spacecraft are being conceived that are highly flexible and of extreme size. The two features of flexibility and size pose new problems in control system design. Since large scale structures are not testable in ground based facilities, the decision on component placement must be made prior to full-scale tests on the spacecraft. Control law research is directed at solving problems of inadequate modelling knowledge prior to operation required to achieve peak performance. Another crucial problem addressed is accommodating failures in systems with smart components that are physically distributed on highly flexible structures. Parameter adaptive control is a method of promise that provides on-orbit tuning of the control system to improve performance by upgrading the mathematical model of the spacecraft during operation. Two specific questions are answered in this work. They are: What limits does on-line parameter identification with realistic sensors and actuators place on the ultimate achievable performance of a system in the highly flexible environment? Also, how well must the mathematical model used in on-board analytic redundancy be known and what are the reasonable expectations for advanced redundancy management schemes in the highly flexible and distributed component environment?

Hybrid Genetic Algorithm - Local Search Method for Ground-Water Management

NASA Astrophysics Data System (ADS)

Chiu, Y.; Nishikawa, T.; Martin, P.

2008-12-01

Ground-water management problems commonly are formulated as a mixed-integer, non-linear programming problem (MINLP). Relying only on conventional gradient-search methods to solve the management problem is computationally fast; however, the methods may become trapped in a local optimum. Global-optimization schemes can identify the global optimum, but the convergence is very slow when the optimal solution approaches the global optimum. In this study, we developed a hybrid optimization scheme, which includes a genetic algorithm and a gradient-search method, to solve the MINLP. The genetic algorithm identifies a near- optimal solution, and the gradient search uses the near optimum to identify the global optimum. Our methodology is applied to a conjunctive-use project in the Warren ground-water basin, California. Hi- Desert Water District (HDWD), the primary water-manager in the basin, plans to construct a wastewater treatment plant to reduce future septic-tank effluent from reaching the ground-water system. The treated wastewater instead will recharge the ground-water basin via percolation ponds as part of a larger conjunctive-use strategy, subject to State regulations (e.g. minimum distances and travel times). HDWD wishes to identify the least-cost conjunctive-use strategies that control ground-water levels, meet regulations, and identify new production-well locations. As formulated, the MINLP objective is to minimize water-delivery costs subject to constraints including pump capacities, available recharge water, water-supply demand, water-level constraints, and potential new-well locations. The methodology was demonstrated by an enumerative search of the entire feasible solution and comparing the optimum solution with results from the branch-and-bound algorithm. The results also indicate that the hybrid method identifies the global optimum within an affordable computation time. Sensitivity analyses, which include testing different recharge-rate scenarios, pond layouts, and water-supply constraints, indicate that the number of new wells is insensitive to water-supply constraints; however, pumping rates and patterns of the existing wells are sensitive. The locations of new wells are mildly sensitive to the pond layout.

Problems identified by dual sensory impaired older adults in long-term care when using a self-management program: A qualitative study

PubMed Central

Zuidema, Sytse; Vernooij-Dassen, Myrra; Dees, Marianne; Hermsen, Pieter; Kempen, Gertrudis; Graff, Maud

2017-01-01

Objective To gain insights into the problems of dual sensory impaired older adults in long-term care. Insights into these problems are essential for developing adequate policies which address the needs of the increasing population of dual sensory impaired older adults in long-term care. Methods A qualitative study was conducted in parallel with a cluster randomized controlled trial. Dual sensory impaired older adults in the intervention group (n = 47, age range 82–98) were invited by a familiar nurse to identify the problems they wanted to address. Data were taken from the semi-structured intervention diaries in which nurses noted the older adults’ verbal responses during a five-month intervention period in 17 long-term care homes across the Netherlands. The data were analyzed using descriptive statistics and qualitative content analysis based on the Grounded Theory. Findings The 47 dual sensory impaired older adults identified a total of 122 problems. Qualitative content analysis showed that the older adults encountered participation problems and problems controlling what happens in their personal environment. Three categories of participation problems emerged: (1) existential concerns of not belonging or not being able to connect with other people, (2) lack of access to communication, information and mobility, and (3) the desire to be actively involved in care delivery. Two categories of control-in-personal-space problems emerged: (1) lack of control of their own physical belongings, and (2) lack of control regarding the behavior of nurses providing daily care in their personal environment. Conclusions The invasive problems identified indicate that dual sensory impaired older adults experience great existential pressures on their lives. Long-term care providers need to develop and implement policies that identify and address these problems, and be aware of adverse consequences of usual care, in order to improve dual sensory impaired residents’ autonomy and quality of life. PMID:28323846

Problems identified by dual sensory impaired older adults in long-term care when using a self-management program: A qualitative study.

PubMed

Roets-Merken, Lieve; Zuidema, Sytse; Vernooij-Dassen, Myrra; Dees, Marianne; Hermsen, Pieter; Kempen, Gertrudis; Graff, Maud

2017-01-01

To gain insights into the problems of dual sensory impaired older adults in long-term care. Insights into these problems are essential for developing adequate policies which address the needs of the increasing population of dual sensory impaired older adults in long-term care. A qualitative study was conducted in parallel with a cluster randomized controlled trial. Dual sensory impaired older adults in the intervention group (n = 47, age range 82-98) were invited by a familiar nurse to identify the problems they wanted to address. Data were taken from the semi-structured intervention diaries in which nurses noted the older adults' verbal responses during a five-month intervention period in 17 long-term care homes across the Netherlands. The data were analyzed using descriptive statistics and qualitative content analysis based on the Grounded Theory. The 47 dual sensory impaired older adults identified a total of 122 problems. Qualitative content analysis showed that the older adults encountered participation problems and problems controlling what happens in their personal environment. Three categories of participation problems emerged: (1) existential concerns of not belonging or not being able to connect with other people, (2) lack of access to communication, information and mobility, and (3) the desire to be actively involved in care delivery. Two categories of control-in-personal-space problems emerged: (1) lack of control of their own physical belongings, and (2) lack of control regarding the behavior of nurses providing daily care in their personal environment. The invasive problems identified indicate that dual sensory impaired older adults experience great existential pressures on their lives. Long-term care providers need to develop and implement policies that identify and address these problems, and be aware of adverse consequences of usual care, in order to improve dual sensory impaired residents' autonomy and quality of life.

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

Trace Contaminant Control for the International Space Station's Node 1- Analysis, Design, and Verification

NASA Technical Reports Server (NTRS)

Perry, J. L.

2017-01-01

Trace chemical contaminant generation inside crewed spacecraft cabins is a technical and medical problem that must be continuously evaluated. Although passive control through materials selection and active control by adsorption and catalytic oxidation devices is employed during normal operations of a spacecraft, contaminant buildup can still become a problem. Buildup is particularly troublesome during the stages between the final closure of a spacecraft during ground processing and the time that a crewmember enters for the first time during the mission. Typically, the elapsed time between preflight closure and first entry on orbit for spacecraft such as Spacelab modules was 30 days. During that time, the active contamination control systems are not activated and contaminants can potentially build up to levels which exceed the spacecraft maximum allowable concentrations (SMACs) specified by NASA toxicology experts. To prevent excessively high contamination levels at crew entry, the Spacelab active contamination control system was operated for 53 hours just before launch.

Information Handling is the Problem

NASA Technical Reports Server (NTRS)

Malin, Jane T.

2001-01-01

This slide presentation reviews the concerns surrounding the automation of information handling. There are two types of decision support software that supports most Space Station Flight Controllers. one is very simple, and the other is very complex. A middle ground is sought. This is the reason for the Human Centered Autonomous and Assistant Systems Testbed (HCAAST) Project. The aim is to study flight controllers at work, and in the bigger picture, with particular attention to how they handle information and how coordination of multiple teams is performed. The focus of the project is on intelligent assistants to assist in handling information for the flight controllers.

Noise Problems Associated with Ground Operations of Jet Aircraft

NASA Technical Reports Server (NTRS)

Hubbard, Harvey H.

1959-01-01

The nature of the noise-exposure problem for humans and the aircraft-structural-damage problem is each discussed briefly. Some discussion is directed toward available methods of minimizing the effects of noise on ground crews, on the aircraft structure, and on the surrounding community. A bibliography of available papers relating to noise-reduction devices is also included.

Space Students Visit MSFC During STS-35 Astro-1 Mission

NASA Technical Reports Server (NTRS)

1990-01-01

The primary objective of the STS-35 mission was round the clock observation of the celestial sphere in ultraviolet and X-Ray astronomy with the Astro-1 observatory which consisted of four telescopes: the Hopkins Ultraviolet Telescope (HUT); the Wisconsin Ultraviolet Photo-Polarimeter Experiment (WUPPE); the Ultraviolet Imaging Telescope (UIT); and the Broad Band X-Ray Telescope (BBXRT). The Huntsville Operations Support Center (HOSC) Spacelab Payload Operations Control Center (SL POCC) at the Marshall Space Flight Center (MSFC) was the air/ground communication channel used between the astronauts and ground control teams during the Spacelab missions. Teams of controllers and researchers directed on-orbit science operations, sent commands to the spacecraft, received data from experiments aboard the Space Shuttle, adjusted mission schedules to take advantage of unexpected science opportunities or unexpected results, and worked with crew members to resolve problems with their experiments. This photo is of Space classroom students in the Discovery Optics Lab at MSFC during STS-35, ASTRO-1 mission payload operations.

Modeling human target acquisition in ground-to-air weapon systems

NASA Technical Reports Server (NTRS)

Phatak, A. V.; Mohr, R. L.; Vikmanis, M.; Wei, K. C.

1982-01-01

The problems associated with formulating and validating mathematical models for describing and predicting human target acquisition response are considered. In particular, the extension of the human observer model to include the acquisition phase as well as the tracking segment is presented. Relationship of the Observer model structure to the more complex Standard Optimal Control model formulation and to the simpler Transfer Function/Noise representation is discussed. Problems pertinent to structural identifiability and the form of the parameterization are elucidated. A systematic approach toward the identification of the observer acquisition model parameters from ensemble tracking error data is presented.

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.

The BAPE 2 balloon-borne CO2

NASA Technical Reports Server (NTRS)

Degnan, J. J.; Walker, H. E.; Peruso, C. J.; Johnson, E. H.; Klein, B. J.; Mcelroy, J. H.

1972-01-01

The systems and techniques which were utilized in the experiment to establish an air-to-ground CO2 laser heterodyne link are described along with the successes and problems encountered when the heterodyne receiver and laser transmitter package were removed from the controlled environment of the laboratory. Major topics discussed include: existing systems and the underlying principles involved in their operation; experimental techniques and optical alignment methods which were found to be useful; theoretical calculations of signal strengths expected under a variety of test conditions and in actual flight; and the experimental results including problems encountered and their possible solutions.

Flying Boresight for Advanced Testing and Calibration of Tracking Antennas and Flight Path Simulations

NASA Astrophysics Data System (ADS)

Hafner, D.

2015-09-01

The application of ground-based boresight sources for calibration and testing of tracking antennas usually entails various difficulties, mostly due to unwanted ground effects. To avoid this problem, DLR MORABA developed a small, lightweight, frequency-adjustable S-band boresight source, mounted on a small remote-controlled multirotor aircraft. Highly accurate GPS-supported, position and altitude control functions allow both, very steady positioning of the aircraft in mid-air, and precise waypoint-based, semi-autonomous flights. In contrast to fixed near-ground boresight sources this flying setup enables to avoid obstructions in the Fresnel zone between source and antenna. Further, it minimizes ground reflections and other multipath effects which can affect antenna calibration. In addition, the large operating range of a flying boresight simplifies measurements in the far field of the antenna and permits undisturbed antenna pattern tests. A unique application is the realistic simulation of sophisticated flight paths, including overhead tracking and demanding trajectories of fast objects such as sounding rockets. Likewise, dynamic tracking tests are feasible which provide crucial information about the antenna pedestal performance — particularly at high elevations — and reveal weaknesses in the autotrack control loop of tracking antenna systems. During acceptance tests of MORABA's new tracking antennas, a manned aircraft was never used, since the Flying Boresight surpassed all expectations regarding usability, efficiency, and precision. Hence, it became an integral part of MORABA's standard antenna setup and calibration procedures.

Real-Time Meteorological Battlespace Characterization in Support of Sea Power 21

DTIC Science & Technology

2011-02-04

32  5.3  LESSONS LEARNED ....................................................................................... 44  6.  FUTURE WORK...problem with the SWR alignment, which is sometimes re- set during SWR maintenance (see Section 6 ‘Lessons Learned ’ for a case in point). Fig...ground clutter present (discussed in Section 6 ‘Lessons Learned ’), along with the lowest-tilt, quality controlled velocity. Bottom panel shows the

Dreaming is not controlled by hippocampal mechanisms.

PubMed

Solms, Mark

2013-12-01

Links with the Humanities are to be welcomed, but they cannot be exempted from normal scientific criteria. Any hypothesis regarding the function of dreams that is premised on rapid eye movement (REM)/dream isomorphism is unsupportable on empirical grounds. Llewellyn's hypothesis has the further problem of counter-evidence in respect of its claim that dreaming relies upon hippocampal functions. The hypothesis also lacks face validity.

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

Needham, D.; Spearman, A.

This paper describes the design and development of a modular gas control installation which is completely buried, except for a small instrument housing and vent pipe. Buried installations controlling gas pressure have many advantages:- no unsightly or costly housings, protection from damage by vehicles or vandals, no problems of acquisition of sites in built-up areas, no need to divert mains to alternative locations, reduced noise, and easier planning permission associated with environmental aspects. It had not previously been possible to realise these advantages with conventional equipment but a novel concept has emerged which solves the problems and provides additional benefits.more » All the working components of a single stream governor station are installed under a 600mm diameter surface access cover. The essential control elements are contained in a lightweight cartridge which can be exchanged in about 15 minutes by two men working from ground level.« less

Langley's CSI evolutionary model: Phase 2

NASA Technical Reports Server (NTRS)

Horta, Lucas G.; Reaves, Mercedes C.; Elliott, Kenny B.; Belvin, W. Keith; Teter, John E.

1995-01-01

Phase 2 testbed is part of a sequence of laboratory models, developed at NASA Langley Research Center, to enhance our understanding on how to model, control, and design structures for space applications. A key problem with structures that must perform in space is the appearance of unwanted vibrations during operations. Instruments, design independently by different scientists, must share the same vehicle causing them to interact with each other. Once in space, these problems are difficult to correct and therefore, prediction via analysis design, and experiments is very important. Phase 2 laboratory model and its predecessors are designed to fill a gap between theory and practice and to aid in understanding important aspects in modeling, sensor and actuator technology, ground testing techniques, and control design issues. This document provides detailed information on the truss structure and its main components, control computer architecture, and structural models generated along with corresponding experimental results.

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.

Around Marshall

NASA Image and Video Library

1990-12-04

The primary objective of the STS-35 mission was round the clock observation of the celestial sphere in ultraviolet and X-Ray astronomy with the Astro-1 observatory which consisted of four telescopes: the Hopkins Ultraviolet Telescope (HUT); the Wisconsin Ultraviolet Photo-Polarimeter Experiment (WUPPE); the Ultraviolet Imaging Telescope (UIT); and the Broad Band X-Ray Telescope (BBXRT). The Huntsville Operations Support Center (HOSC) Spacelab Payload Operations Control Center (SL POCC) at the Marshall Space Flight Center (MSFC) was the air/ground communication channel used between the astronauts and ground control teams during the Spacelab missions. Teams of controllers and researchers directed on-orbit science operations, sent commands to the spacecraft, received data from experiments aboard the Space Shuttle, adjusted mission schedules to take advantage of unexpected science opportunities or unexpected results, and worked with crew members to resolve problems with their experiments. Due to loss of data used for pointing and operating the ultraviolet telescopes, MSFC ground teams were forced to aim the telescopes with fine tuning by the flight crew. This photo captures the activity of WUPPE (Wisconsin Ultraviolet Photo-Polarimeter Experiment) data review at the Science Operations Area during the mission. This image shows mission activities at the Broad Band X-Ray Telescope (BBXRT) Work Station in the Science Operations Area (SOA).

Apollo experience report: Launch escape propulsion subsystem

NASA Technical Reports Server (NTRS)

Townsend, N. A.

1973-01-01

The Apollo launch escape propulsion subsystem contained three solid rocket motors. The general design, development, and qualification of the solid-propellant pitch-control, tower-jettison, and launch-escape motors of the Apollo launch escape propulsion subsystem were completed during years 1961 to 1966. The launch escape system components are described in general terms, and the sequence of events through the ground-based test programs and flight-test programs is discussed. The initial ground rules established for this system were that it should use existing technology and designs as much as possible. The practicality of this decision is proved by the minimum number of problems that were encountered during the development and qualification program.

An Open-source Community Web Site To Support Ground-Water Model Testing

NASA Astrophysics Data System (ADS)

Kraemer, S. R.; Bakker, M.; Craig, J. R.

2007-12-01

A community wiki wiki web site has been created as a resource to support ground-water model development and testing. The Groundwater Gourmet wiki is a repository for user supplied analytical and numerical recipes, howtos, and examples. Members are encouraged to submit analytical solutions, including source code and documentation. A diversity of code snippets are sought in a variety of languages, including Fortran, C, C++, Matlab, Python. In the spirit of a wiki, all contributions may be edited and altered by other users, and open source licensing is promoted. Community accepted contributions are graduated into the library of analytic solutions and organized into either a Strack (Groundwater Mechanics, 1989) or Bruggeman (Analytical Solutions of Geohydrological Problems, 1999) classification. The examples section of the wiki are meant to include laboratory experiments (e.g., Hele Shaw), classical benchmark problems (e.g., Henry Problem), and controlled field experiments (e.g., Borden landfill and Cape Cod tracer tests). Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.

Water-quality assessment of the Smith River drainage basin, California and Oregon

USGS Publications Warehouse

Iwatsubo, Rick T.; Washabaugh, Donna S.

1982-01-01

A water-quality assessment of the Smith River drainage basin was made to provide a summary of the water-quality conditions including known or potential water-quality problems. Results of the study showed that the water quality of the Smith River is excellent and generally meets the water-quality objectives for the beneficial uses identified by the California Regional Water Quality Control Board, North Coast Region. Known and potential problems related to water quality include: Sedimentation resulting from both natural erosional processes and land-use activities such as timber harvest, road construction, and mining that accelerate the erosional processes; bacterial contamination of surface and ground waters from inundated septic tanks and drainfields, and grazing activities; industrial spills which have resulted in fish kills and oil residues; high concetrations of iron in ground water; log and debris jams creating fish migration barriers; and pesticide and trace-element contamination from timber-harvest and mining activities, respectively. Future studies are needed to establish: (1) a sustained long-term monitoring program to provide a broad coverage of water-quality conditions in order to define long-term water-quality trends; and (2) interpretive studies to determine the source of known and potential water-quality problems. (USGS)

Large-scale block adjustment without use of ground control points based on the compensation of geometric calibration for ZY-3 images

NASA Astrophysics Data System (ADS)

Yang, Bo; Wang, Mi; Xu, Wen; Li, Deren; Gong, Jianya; Pi, Yingdong

2017-12-01

The potential of large-scale block adjustment (BA) without ground control points (GCPs) has long been a concern among photogrammetric researchers, which is of effective guiding significance for global mapping. However, significant problems with the accuracy and efficiency of this method remain to be solved. In this study, we analyzed the effects of geometric errors on BA, and then developed a step-wise BA method to conduct integrated processing of large-scale ZY-3 satellite images without GCPs. We first pre-processed the BA data, by adopting a geometric calibration (GC) method based on the viewing-angle model to compensate for systematic errors, such that the BA input images were of good initial geometric quality. The second step was integrated BA without GCPs, in which a series of technical methods were used to solve bottleneck problems and ensure accuracy and efficiency. The BA model, based on virtual control points (VCPs), was constructed to address the rank deficiency problem caused by lack of absolute constraints. We then developed a parallel matching strategy to improve the efficiency of tie points (TPs) matching, and adopted a three-array data structure based on sparsity to relieve the storage and calculation burden of the high-order modified equation. Finally, we used the conjugate gradient method to improve the speed of solving the high-order equations. To evaluate the feasibility of the presented large-scale BA method, we conducted three experiments on real data collected by the ZY-3 satellite. The experimental results indicate that the presented method can effectively improve the geometric accuracies of ZY-3 satellite images. This study demonstrates the feasibility of large-scale mapping without GCPs.

Ground water hydraulics as a geophysical aid

USGS Publications Warehouse

Ferris, John G.

1948-01-01

The publication of the non-equilibrium formula in 1935 in a paper by Theis marked the opening of a new era in the analysis and understanding of the hydraulics of percolating ground waters. Through the past decade 9 an ever-increasing number of engineers and geologists have become familiar-with the application of this formula to practical problems of ground-water flow and have tested it in the field, against precise observations, under controlled conditions. Although the highly idealized aquifer assumed for the derivation of this formula is not of widespread occurrence in the field, we gain increasing confidence in the use of the Theis method as our backlog of proven data accumulates until we now look askance at test data which do not conform to this theory. In many cases, careful study of these anomalous data will reveal the means for estimating the degree or manner in which an observed aquifer diverges from the idealized aquifer.

Photogrammetry on glaciers: Old and new knowledge

NASA Astrophysics Data System (ADS)

Pfeffer, W. T.; Welty, E.; O'Neel, S.

2014-12-01

In the past few decades terrestrial photogrammetry has become a widely used tool for glaciological research, brought about in part by the proliferation of high-quality, low-cost digital cameras, dramatic increases in image-processing power of computers, and very innovative progress in image processing, much of which has come from computer vision research and from the computer gaming industry. At present, glaciologists have developed their capacity to gather images much further than their ability to process them. Many researchers have accumulated vast inventories of imagery, but have no efficient means to extract the data they desire from them. In many cases these are single-image time series where the processing limitation lies in the paucity of methods to obtain 3-dimension object space information from measurements in the 2-dimensional image space; in other cases camera pairs have been operated but no automated means is in hand for conventional stereometric analysis of many thousands of image pairs. Often the processing task is further complicated by weak camera geometry or ground control distribution, either of which will compromise the quality of 3-dimensional object space solutions. Solutions exist for many of these problems, found sometimes among the latest computer vision results, and sometimes buried in decades-old pre-digital terrestrial photogrammetric literature. Other problems, particularly those arising from poorly constrained or underdetermined camera and ground control geometry, may be unsolvable. Small-scale, ground-based photography and photogrammetry of glaciers has grown over the past few decades in an organic and disorganized fashion, with much duplication of effort and little coordination or sharing of knowledge among researchers. Given the utility of terrestrial photogrammetry, its low cost (if properly developed and implemented), and the substantial value of the information to be had from it, some further effort to share knowledge and methods would be a great benefit for the community. We consider some of the main problems to be solved, and aspects of how optimal knowledge sharing might be accomplished.

Potential effects of the introduction of the discrete address beacon system data link on air/ground information transfer problems

NASA Technical Reports Server (NTRS)

Grayson, R. L.

1981-01-01

This study of Aviation Safety Reporting System reports suggests that benefits should accure from implementation of discrete address beacon system data link. The phase enhanced terminal information system service is expected to provide better terminal information than present systems by improving currency and accuracy. In the exchange of air traffic control messages, discrete address insures that only the intended recipient receives and acts on a specific message. Visual displays and printer copy of messages should mitigate many of the reported problems associated with voice communications. The problems that remain unaffected include error in addressing the intended recipient and messages whose content is wrong but are otherwise correct as to format and reasonableness.

Locomotor Sub-functions for Control of Assistive Wearable Robots.

PubMed

Sharbafi, Maziar A; Seyfarth, Andre; Zhao, Guoping

2017-01-01

A primary goal of comparative biomechanics is to understand the fundamental physics of locomotion within an evolutionary context. Such an understanding of legged locomotion results in a transition from copying nature to borrowing strategies for interacting with the physical world regarding design and control of bio-inspired legged robots or robotic assistive devices. Inspired from nature, legged locomotion can be composed of three locomotor sub-functions, which are intrinsically interrelated: Stance : redirecting the center of mass by exerting forces on the ground. Swing : cycling the legs between ground contacts. Balance : maintaining body posture. With these three sub-functions, one can understand, design and control legged locomotory systems with formulating them in simpler separated tasks. Coordination between locomotor sub-functions in a harmonized manner appears then as an additional problem when considering legged locomotion. However, biological locomotion shows that appropriate design and control of each sub-function simplifies coordination. It means that only limited exchange of sensory information between the different locomotor sub-function controllers is required enabling the envisioned modular architecture of the locomotion control system. In this paper, we present different studies on implementing different locomotor sub-function controllers on models, robots, and an exoskeleton in addition to demonstrating their abilities in explaining humans' control strategies.

Locomotor Sub-functions for Control of Assistive Wearable Robots

PubMed Central

Sharbafi, Maziar A.; Seyfarth, Andre; Zhao, Guoping

2017-01-01

A primary goal of comparative biomechanics is to understand the fundamental physics of locomotion within an evolutionary context. Such an understanding of legged locomotion results in a transition from copying nature to borrowing strategies for interacting with the physical world regarding design and control of bio-inspired legged robots or robotic assistive devices. Inspired from nature, legged locomotion can be composed of three locomotor sub-functions, which are intrinsically interrelated: Stance: redirecting the center of mass by exerting forces on the ground. Swing: cycling the legs between ground contacts. Balance: maintaining body posture. With these three sub-functions, one can understand, design and control legged locomotory systems with formulating them in simpler separated tasks. Coordination between locomotor sub-functions in a harmonized manner appears then as an additional problem when considering legged locomotion. However, biological locomotion shows that appropriate design and control of each sub-function simplifies coordination. It means that only limited exchange of sensory information between the different locomotor sub-function controllers is required enabling the envisioned modular architecture of the locomotion control system. In this paper, we present different studies on implementing different locomotor sub-function controllers on models, robots, and an exoskeleton in addition to demonstrating their abilities in explaining humans' control strategies. PMID:28928650

Robust energy-absorbing compensators for the ACTEX II test article

NASA Astrophysics Data System (ADS)

Blaurock, Carl A.; Miller, David W.; Nye, Ted

1995-05-01

The paper addresses the problem of satellite solar panel vibration. A multi-layer vibration control scheme is investigated using a flight test article. Key issues in the active control portion are presented in the paper. The paper discusses the primary control design drivers, which are the time variations in modal frequencies due to configuration and thermal changes. A local control design approach is investigated, but found to be unworkable due to sensor/actuator non-collocation. An alternate design process uses linear robust control techniques, by describing the modal shifts as uncertainties. Multiple modal design, alpha- shifted multiple model, and a feedthrough compensation scheme are examined. Ground and simulation tests demonstrate that the resulting controllers provide significant vibration reduction in the presence of expected system variations.

Design of power cable grounding wire anti-theft monitoring system

NASA Astrophysics Data System (ADS)

An, Xisheng; Lu, Peng; Wei, Niansheng; Hong, Gang

2018-01-01

In order to prevent the serious consequences of the power grid failure caused by the power cable grounding wire theft, this paper presents a GPRS based power cable grounding wire anti-theft monitoring device system, which includes a camera module, a sensor module, a micro processing system module, and a data monitoring center module, a mobile terminal module. Our design utilize two kinds of methods for detecting and reporting comprehensive image, it can effectively solve the problem of power and cable grounding wire box theft problem, timely follow-up grounded cable theft events, prevent the occurrence of electric field of high voltage transmission line fault, improve the reliability of the safe operation of power grid.

Trajectory Design Employing Convex Optimization for Landing on Irregularly Shaped Asteroids

NASA Technical Reports Server (NTRS)

Pinson, Robin M.; Lu, Ping

2016-01-01

Mission proposals that land spacecraft on asteroids are becoming increasingly popular. However, in order to have a successful mission the spacecraft must reliably and softly land at the intended landing site with pinpoint precision. The problem under investigation is how to design a propellant optimal powered descent trajectory that can be quickly computed onboard the spacecraft, without interaction from the ground control. The propellant optimal control problem in this work is to determine the optimal finite thrust vector to land the spacecraft at a specified location, in the presence of a highly nonlinear gravity field, subject to various mission and operational constraints. The proposed solution uses convex optimization, a gravity model with higher fidelity than Newtonian, and an iterative solution process for a fixed final time problem. In addition, a second optimization method is wrapped around the convex optimization problem to determine the optimal flight time that yields the lowest propellant usage over all flight times. Gravity models designed for irregularly shaped asteroids are investigated. Success of the algorithm is demonstrated by designing powered descent trajectories for the elongated binary asteroid Castalia.

The Effects of Lunar Dust on EVA Systems During the Apollo Missions

NASA Technical Reports Server (NTRS)

Gaier, James R.

2005-01-01

Mission documents from the six Apollo missions that landed on the lunar surface have been studied in order to catalog the effects of lunar dust on Extra-Vehicular Activity (EVA) systems, primarily the Apollo surface space suit. It was found that the effects could be sorted into nine categories: vision obscuration, false instrument readings, dust coating and contamination, loss of traction, clogging of mechanisms, abrasion, thermal control problems, seal failures, and inhalation and irritation. Although simple dust mitigation measures were sufficient to mitigate some of the problems (i.e., loss of traction) it was found that these measures were ineffective to mitigate many of the more serious problems (i.e., clogging, abrasion, diminished heat rejection). The severity of the dust problems were consistently underestimated by ground tests, indicating a need to develop better simulation facilities and procedures.

The Effects of Lunar Dust on EVA Systems During the Apollo Missions

NASA Technical Reports Server (NTRS)

Gaier, James R.

2007-01-01

Mission documents from the six Apollo missions that landed on the lunar surface have been studied in order to catalog the effects of lunar dust on Extra-Vehicular Activity (EVA) systems, primarily the Apollo surface space suit. It was found that the effects could be sorted into nine categories: vision obscuration, false instrument readings, dust coating and contamination, loss of traction, clogging of mechanisms, abrasion, thermal control problems, seal failures, and inhalation and irritation. Although simple dust mitigation measures were sufficient to mitigate some of the problems (i.e., loss of traction) it was found that these measures were ineffective to mitigate many of the more serious problems (i.e., clogging, abrasion, diminished heat rejection). The severity of the dust problems were consistently underestimated by ground tests, indicating a need to develop better simulation facilities and procedures.

Structures vibration control via Tuned Mass Dampers using a co-evolution Coral Reefs Optimization algorithm

NASA Astrophysics Data System (ADS)

Salcedo-Sanz, S.; Camacho-Gómez, C.; Magdaleno, A.; Pereira, E.; Lorenzana, A.

2017-04-01

In this paper we tackle a problem of optimal design and location of Tuned Mass Dampers (TMDs) for structures subjected to earthquake ground motions, using a novel meta-heuristic algorithm. Specifically, the Coral Reefs Optimization (CRO) with Substrate Layer (CRO-SL) is proposed as a competitive co-evolution algorithm with different exploration procedures within a single population of solutions. The proposed approach is able to solve the TMD design and location problem, by exploiting the combination of different types of searching mechanisms. This promotes a powerful evolutionary-like algorithm for optimization problems, which is shown to be very effective in this particular problem of TMDs tuning. The proposed algorithm's performance has been evaluated and compared with several reference algorithms in two building models with two and four floors, respectively.

Analysis of ground state in random bipartite matching

NASA Astrophysics Data System (ADS)

Shi, Gui-Yuan; Kong, Yi-Xiu; Liao, Hao; Zhang, Yi-Cheng

2016-02-01

Bipartite matching problems emerge in many human social phenomena. In this paper, we study the ground state of the Gale-Shapley model, which is the most popular bipartite matching model. We apply the Kuhn-Munkres algorithm to compute the numerical ground state of the model. For the first time, we obtain the number of blocking pairs which is a measure of the system instability. We also show that the number of blocking pairs formed by each person follows a geometric distribution. Furthermore, we study how the connectivity in the bipartite matching problems influences the instability of the ground state.

Autonomous search and surveillance with small fixed wing aircraft

NASA Astrophysics Data System (ADS)

McGee, Timothy Garland

Small unmanned aerial vehicles (UAVs) have the potential to act as low cost tools in a variety of both civilian and military applications including traffic monitoring, border patrol, and search and rescue. While most current operational UAV systems require human operators, advances in autonomy will allow these systems to reach their full potential as sensor platforms. This dissertation specifically focuses on developing advanced control, path planning, search, and image processing techniques that allow small fixed wing aircraft to autonomously collect data. The problems explored were motivated by experience with the development and experimental flight testing of a fleet of small autonomous fixed wing aircraft. These issues, which have not been fully addressed in past work done on ground vehicles or autonomous helicopters, include the influence of wind and turning rate constraints, the non-negligible velocity of ground targets relative to the aircraft velocity, and limitations on sensor size and processing power on small vehicles. Several contributions for the autonomous operation of small fixed wing aircraft are presented. Several sliding surface controllers are designed which extend previous techniques to include variable sliding surface coefficients and the use of spatial vehicle dynamics. These advances eliminate potential singularities in the control laws to follow spatially defined paths and allow smooth transition between controllers. The optimal solution for the problem of path planning through an ordered set of points for an aircraft with a bounded turning rate in the presence of a constant wind is then discussed. Path planning strategies are also explored to guarantee that a searcher will travel within sensing distance of a mobile ground target. This work assumes only a maximum velocity of the target and is designed to succeed for any possible path of the target. Closed-loop approximations of both the path planning and search techniques, using the sliding surface controllers already discussed, are also studied. Finally, a novel method is presented to detect obstacles by segmenting an image into sky and non-sky regions. The feasibility of this method is demonstrated experimentally on an aircraft test bed.

Aids and the Police

DTIC Science & Technology

1990-01-01

emergency medical personnel arrived, he fought their rescue attempts and had to be wrestled to the ground. All the time he was coughing, spitting and...infection. In fact, no emergency worker has been reported to the Centers for Disease Control (CDC) as contracting HIV clearly as a result of job-related...important variable of the AIDS problem, but also stress the necessity of addressing thc, entire issue from a strategic management perspective . This analysis

Knowledge-Acquisition Tool For Expert System

NASA Technical Reports Server (NTRS)

Disbrow, James D.; Duke, Eugene L.; Regenie, Victoria A.

1988-01-01

Digital flight-control systems monitored by computer program that evaluates and recommends. Flight-systems engineers for advanced, high-performance aircraft use knowlege-acquisition tool for expert-system flight-status monitor suppling interpretative data. Interpretative function especially important in time-critical, high-stress situations because it facilitates problem identification and corrective strategy. Conditions evaluated and recommendations made by ground-based engineers having essential knowledge for analysis and monitoring of performances of advanced aircraft systems.

Ground Taxi Navigation Problems and Training Solutions

NASA Technical Reports Server (NTRS)

Quinn, Cheryl; Walter, Kim E.; Rosekind, Mark (Technical Monitor)

1997-01-01

Adverse weather conditions can put considerable strain on the National Airspace System. Even small decreases in visibility on the airport surface can create delays, hinder safe movement and lead to errors. Studies of Aviation Safety Reporting System (ASRS) surface movement incidents support the need for technologies and procedures to improve ground operations in low-visibility conditions. This study examined 139 ASRS reports of low-visibility surface movement incidents at 10 major U.S. airports. Errors were characterized in terms of incident type, contributing factors and consequences. The incidents in the present sample were comprised of runway transgressions, taxiway excursions and ground conflicts. The primary contributing factors were Airport Layout and Markings, Communication and Distraction. In half the incidents the controller issued a new clearance or the flight crew took an evasive action and in the remaining half, no recovery attempt was made because the error was detected after the fact. By gaining a better understanding the factors that affect crew navigation in low visibility and the types of errors that are likely to occur, it will be possible to develop more robust technologies to aid pilots in the ground taxi task. Implications for crew training and procedure development for low-visibility ground taxi are also discussed.

Water Resources Investigations at Edwards Air Force Base since 1988

USGS Publications Warehouse

Sneed, Michelle; Nishikawa, Tracy; Martin, Peter

2006-01-01

Edwards Air Force Base (EAFB) in southern California (fig. 1) has relied on ground water to meet its water-supply needs. The extraction of ground water has led to two major problems that can directly affect the mission of EAFB: declining water levels (more than 120 ft since the 1920s) and land subsidence, a gradual downward movement of the land surface (more than 4 ft since the late 1920s). As water levels decline, this valuable resource becomes depleted, thus requiring mitigating measures. Land subsidence has caused cracked (fissured) runways and accelerated erosion on Rogers lakebed. In 1988, the U.S. Geological Survey (USGS), in cooperation with the U.S. Air Force, began investigations of the effects of declining water levels and land subsidence at EAFB and possible mitigation measures, such as the injection of imported surface water into the ground-water system. The cooperative investigations included data collection and analyses, numerical simulations of ground-water flow and land subsidence, and development of a preliminary simulation-optimization model. The results of these investigations indicate that the injection of imported water may help to control land subsidence; however, the potential ground-water-quality impacts are unknown.

Effects of irrigation pumping on the ground-water system in Newton and Jasper Counties, Indiana

USGS Publications Warehouse

Bergeron, Marcel P.

1981-01-01

Flow in the ground-water system in Newton and Jasper Counties, Indiana, was simulated in a quasi-three-dimensional model in a study of irrigation use of ground water in the two counties. The ground-water system consists of three aquifers: (1) a surficial coarse sand aquifer known as the Kankakee aquifer, (2) a limestone and dolomite bedrock aquifer, and (3) a sand and gravel bedrock valley aquifer. Irrigation pumping, derived primarily from the bedrock, was estimated to be 34.8 million gallons per day during peak irrigation in 1977. Acreage irrigated with ground water is estimated to be 6,200 acres. A series of model experiments was used to estimate the effects of irrigation pumping on ground-water levels and streamflow. Model analysis indicates that a major factor controlling drawdown due to pumping in the bedrock aquifer are the variations in thickness and in vertical hydraulic conductivity in a semiconfining unit overlying the bedrock. Streamflow was not significantly reduced by hypothetical withdrawals of 12.6 million gallons per day from the bedrock aquifer and 10.3 million gallons per day in the Kankakee aquifer. Simulation of water-level recovery after irrigation pumping indicated that a 5-year period of alternating between increasing pumping and recovery will not cause serious problems of residual drawdown or ground-water mining. 

Fixation procedure for transmission electron microscopy of Chara rhizoids under microgravity in a Spacelab (IML-2).

PubMed

Braun, M; Buchen, B; Sievers, A

1996-06-27

A special fixation device and fixation procedure have been developed to investigate for the first time the ultrastructure of gravity-sensing, unicellular Chara rhizoids grown for 30 h under microgravity (MG) conditions during the IML-2 mission. The fixation unit allowed culture, fixation and storage of Chara rhizoids in the same chamber without transferring the samples. The procedure was easy and safe to perform and required a minimum of crew time. Rhizoids fixated with glutaraldehyde in space and further processed for electron microscopy on ground showed that the fixation was of high quality and corresponded to the fixation quality of rhizoids in the ground controls. Thus, the equipment accomplished the manifold problems related to the physical effects of MG. The polarity of the rhizoids was maintained in MG. Well-preserved organelles and microtubules showed no obvious difference in ultrastructure or distribution after 30-h growth in MG compared to ground controls. The statoliths were more randomly distributed, however, only up to 50 microns basal to the tip. Thus, changing the gravity conditions does to disturb the cellular organisation of the rhizoids enabling the tip-growing cells to follow their genetic program in development and growth also under MG.

NASA aviation safety reporting system

NASA Technical Reports Server (NTRS)

1978-01-01

Reports describing various types of communication problems are presented along with summaries dealing with judgment and decision making. Concerns relating to the ground proximity warning system are summarized and several examples of true terrain proximity warnings are provided. An analytic study of reports relating to profile descents was performed. Problems were found to be associated with charting and graphic presentation of the descents, with lack of uniformity of the descent procedures among facilities using them, and with the flight crew workload engendered by profile descents, particularly when additional requirements are interposed by air traffic control during the execution of the profiles. A selection of alert bulletins and responses to them were reviewed.

Human vs autonomous control of planetary roving vehicles

NASA Technical Reports Server (NTRS)

Whitney, W. M.

1974-01-01

Supervisory or semiautonomous control has some compelling advantages over step-by-step human command and verification for the operation of roving vehicles on remote planetary surfaces. There are also disadvantages in relation to the complex system that must be mobilized and the chain of events that must be enacted to conduct a mission. Which of the two control methods is better on technical grounds may not be the deciding factor in its acceptance or rejection. Some of the issues that affect changes in spacecraft design and operation are summarized. To accelerate the movement toward more autonomous machines, it will be necessary to understand and to address the problems that such autonomy will create for other elements of the control system and for the control process.

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. ...

A dataset of stereoscopic images and ground-truth disparity mimicking human fixations in peripersonal space

PubMed Central

Canessa, Andrea; Gibaldi, Agostino; Chessa, Manuela; Fato, Marco; Solari, Fabio; Sabatini, Silvio P.

2017-01-01

Binocular stereopsis is the ability of a visual system, belonging to a live being or a machine, to interpret the different visual information deriving from two eyes/cameras for depth perception. From this perspective, the ground-truth information about three-dimensional visual space, which is hardly available, is an ideal tool both for evaluating human performance and for benchmarking machine vision algorithms. In the present work, we implemented a rendering methodology in which the camera pose mimics realistic eye pose for a fixating observer, thus including convergent eye geometry and cyclotorsion. The virtual environment we developed relies on highly accurate 3D virtual models, and its full controllability allows us to obtain the stereoscopic pairs together with the ground-truth depth and camera pose information. We thus created a stereoscopic dataset: GENUA PESTO—GENoa hUman Active fixation database: PEripersonal space STereoscopic images and grOund truth disparity. The dataset aims to provide a unified framework useful for a number of problems relevant to human and computer vision, from scene exploration and eye movement studies to 3D scene reconstruction. PMID:28350382

Apollo 13: Houston, We've Got a Problem

NASA Technical Reports Server (NTRS)

1991-01-01

This video contains historical footage of the flight of Apollo-13, the fifth Lunar Mission and the third spacecraft that was to land on the Moon. Apollo-13's launch date was April 11, 1970. On the 13th of April, after docking with the Lunar Module, the astronauts, Jim Lovell, Fred Haise, and Jack Swiggert, discovered that their oxygen tanks had ruptured and ended up entering and returning to Earth in the Lunar Module instead of the Command Module. There is footage of inside module and Mission Control shots, personal commentary by the astronauts concerning the problems as they developed, national news footage and commentary, and a post-flight Presidential Address by President Richard Nixon. Film footage of the approach to the Moon and departing from Earth, and air-to-ground communication with Mission Control is included.

Apollo 13: Houston, we've got a problem

NASA Astrophysics Data System (ADS)

1991-04-01

This video contains historical footage of the flight of Apollo-13, the fifth Lunar Mission and the third spacecraft that was to land on the Moon. Apollo-13's launch date was April 11, 1970. On the 13th of April, after docking with the Lunar Module, the astronauts, Jim Lovell, Fred Haise, and Jack Swiggert, discovered that their oxygen tanks had ruptured and ended up entering and returning to Earth in the Lunar Module instead of the Command Module. There is footage of inside module and Mission Control shots, personal commentary by the astronauts concerning the problems as they developed, national news footage and commentary, and a post-flight Presidential Address by President Richard Nixon. Film footage of the approach to the Moon and departing from Earth, and air-to-ground communication with Mission Control is included.

Application of digital profile modeling techniques to ground-water solute transport at Barstow, California

USGS Publications Warehouse

Robson, Stanley G.

1978-01-01

This study investigated the use of a two-dimensional profile-oriented water-quality model for the simulation of head and water-quality changes through the saturated thickness of an aquifer. The profile model is able to simulate confined or unconfined aquifers with nonhomogeneous anisotropic hydraulic conductivity, nonhomogeneous specific storage and porosity, and nonuniform saturated thickness. An aquifer may be simulated under either steady or nonsteady flow conditions provided that the ground-water flow path along which the longitudinal axis of the model is oriented does not move in the aquifer during the simulation time period. The profile model parameters are more difficult to quantify than are the corresponding parameters for an areal-oriented water-fluality model. However, the sensitivity of the profile model to the parameters may be such that the normal error of parameter estimation will not preclude obtaining acceptable model results. Although the profile model has the advantage of being able to simulate vertical flow and water-quality changes in a single- or multiple-aquifer system, the types of problems to which it can be applied is limited by the requirements that (1) the ground-water flow path remain oriented along the longitudinal axis of the model and (2) any subsequent hydrologic factors to be evaluated using the model must be located along the land-surface trace of the model. Simulation of hypothetical ground-water management practices indicates that the profile model is applicable to problem-oriented studies and can provide quantitative results applicable to a variety of management practices. In particular, simulations of the movement and dissolved-solids concentration of a zone of degraded ground-water quality near Barstow, Calif., indicate that halting subsurface disposal of treated sewage effluent in conjunction with pumping a line of fully penetrating wells would be an effective means of controlling the movement of degraded ground water.

Summary appraisals of the Nation's ground-water resources; South Atlantic Gulf region

USGS Publications Warehouse

Cederstrom, D.J.; Boswell, E.H.; Tarver, G.R.

1979-01-01

Ground-water problems generally are not severe. Critical situations are restricted to areas where large quantities of ground water are being withdrawn or where aquifers are contaminated by oil-field or industrial waste. Large withdrawals in coastal areas have caused some saltwater intrusion. In other localities, highly mineralized water may have migrated along fault zones to freshwater aquifers. Many of the present problems can be resolved or ameliorated by redistributing withdrawals or developing alternative water sources.

MODFLOW-2000 Ground-Water Model?User Guide to the Subsidence and Aquifer-System Compaction (SUB) Package

USGS Publications Warehouse

Hoffmann, Jörn; Leake, S.A.; Galloway, D.L.; Wilson, Alicia M.

2003-01-01

This report documents a computer program, the Subsidence and Aquifer-System Compaction (SUB) Package, to simulate aquifer-system compaction and land subsidence using the U.S. Geological Survey modular finite-difference ground-water flow model, MODFLOW-2000. The SUB Package simulates elastic (recoverable) compaction and expansion, and inelastic (permanent) compaction of compressible fine-grained beds (interbeds) within the aquifers. The deformation of the interbeds is caused by head or pore-pressure changes, and thus by changes in effective stress, within the interbeds. If the stress is less than the preconsolidation stress of the sediments, the deformation is elastic; if the stress is greater than the preconsolidation stress, the deformation is inelastic. The propagation of head changes within the interbeds is defined by a transient, one-dimensional (vertical) diffusion equation. This equation accounts for delayed release of water from storage or uptake of water into storage in the interbeds. Properties that control the timing of the storage changes are vertical hydraulic diffusivity and interbed thickness. The SUB Package supersedes the Interbed Storage Package (IBS1) for MODFLOW, which assumes that water is released from or taken into storage with changes in head in the aquifer within a single model time step and, therefore, can be reasonably used to simulate only thin interbeds. The SUB Package relaxes this assumption and can be used to simulate time-dependent drainage and compaction of thick interbeds and confining units. The time-dependent drainage can be turned off, in which case the SUB Package gives results identical to those from IBS1. Three sample problems illustrate the usefulness of the SUB Package. One sample problem verifies that the package works correctly. This sample problem simulates the drainage of a thick interbed in response to a step change in head in the adjacent aquifer and closely matches the analytical solution. A second sample problem illustrates the effects of seasonally varying discharge and recharge to an aquifer system with a thick interbed. A third sample problem simulates a multilayered regional ground-water basin. Model input files for the third sample problem are included in the appendix.

Comparison of radar and infrared distance sensors for intelligent cruise control systems

NASA Astrophysics Data System (ADS)

Hoess, Alfred; Hosp, Werner; Rauner, Hans

1995-09-01

In this paper, infrared distance sensors are compared regarding technology, environmental, and practical aspects. Different methods for obtaining lateral resolution and covering the required detection range are presented for both sensor technologies. Possible positions for sensor installation at the test vehicle have been tested. Experimental results regarding cleaning devices and other environmental problems are presented. Finally, future aspects, e.g. speed over ground measurements or technological steps are discussed.

Range and mission scheduling automation using combined AI and operations research techniques

NASA Technical Reports Server (NTRS)

Arbabi, Mansur; Pfeifer, Michael

1987-01-01

Ground-based systems for Satellite Command, Control, and Communications (C3) operations require a method for planning, scheduling and assigning the range resources such as: antenna systems scattered around the world, communications systems, and personnel. The method must accommodate user priorities, last minute changes, maintenance requirements, and exceptions from nominal requirements. Described are computer programs which solve 24 hour scheduling problems, using heuristic algorithms and a real time interactive scheduling process.

Skylab

NASA Image and Video Library

1992-01-22

The primary payload for Space Shuttle Mission STS-42, launched January 22, 1992, was the International Microgravity Laboratory-1 (IML-1), a pressurized manned Spacelab module. The goal of IML-1 was to explore in depth the complex effects of weightlessness of living organisms and materials processing. Around-the-clock research was performed on the human nervous system's adaptation to low gravity and effects of microgravity on other life forms such as shrimp eggs, lentil seedlings, fruit fly eggs, and bacteria. Materials processing experiments were also conducted, including crystal growth from a variety of substances such as enzymes, mercury iodide and a virus. The Huntsville Operations Support Center (HOSC) Spacelab Payload Operations Control Center (SL POCC) at the Marshall Space Flight Center (MSFC) was the air/ground communication channel used between the astronauts aboard the Spacelab and scientists, researchers, and ground control teams during the Spacelab missions. The facility made instantaneous video and audio communications possible for scientists on the ground to follow the progress and to send direct commands of their research almost as if they were in space with the crew. Teams of controllers and researchers directed on-orbit science operations, sent commands to the spacecraft, received data from experiments aboard the Space Shuttle, adjusted mission schedules to take advantage of unexpected science opportunities or unexpected results, and worked with crew members to resolve problems with their experiments. In this photograph the Payload Operations Director (POD) views the launch.

MODFLOW/MT3DMS-based simulation of variable-density ground water flow and transport

USGS Publications Warehouse

Langevin, C.D.; Guo, W.

2006-01-01

This paper presents an approach for coupling MODFLOW and MT3DMS for the simulation of variable-density ground water flow. MODFLOW routines were modified to solve a variable-density form of the ground water flow equation in which the density terms are calculated using an equation of state and the simulated MT3DMS solute concentrations. Changes to the MODFLOW and MT3DMS input files were kept to a minimum, and thus existing data files and data files created with most pre- and postprocessors can be used directly with the SEAWAT code. The approach was tested by simulating the Henry problem and two of the saltpool laboratory experiments (low- and high-density cases). For the Henry problem, the simulated results compared well with the steady-state semianalytic solution and also the transient isochlor movement as simulated by a finite-element model. For the saltpool problem, the simulated breakthrough curves compared better with the laboratory measurements for the low-density case than for the high-density case but showed good agreement with the measured salinity isosurfaces for both cases. Results from the test cases presented here indicate that the MODFLOW/MT3DMS approach provides accurate solutions for problems involving variable-density ground water flow and solute transport. ?? 2006 National Ground Water Association.

Sharing Solutions: Persistence and Grounding in Multimodal Collaborative Problem Solving

ERIC Educational Resources Information Center

Dillenbourg, Pierre; Traum, David

2006-01-01

This article reports on an exploratory study of the relationship between grounding and problem solving in multimodal computer-mediated collaboration. This article examines two different media, a shared whiteboard and a MOO environment that includes a text chat facility. A study was done on how the acknowledgment rate (how often partners give…

A BAYES LIKELIHOOD INFORMATION THEORETIC APPROACH FOR THE EXOGENOUS AGGREGATION OF REGIONAL GROUND WATER QUALITY DATA

EPA Science Inventory

This work addresses a potentially serious problem in analysis or synthesis of spatially explicit data on ground water quality from wells, known to geographers as the modifiable areal unit problem (MAUP). It results from the fact that in regional aggregation of spatial data, inves...

Galileo Attitude Determination: Experiences with a Rotating Star Scanner

NASA Technical Reports Server (NTRS)

Merken, L.; Singh, G.

1991-01-01

The Galileo experience with a rotating star scanner is discussed in terms of problems encountered in flight, solutions implemented, and lessons learned. An overview of the Galileo project and the attitude and articulation control subsystem is given and the star scanner hardware and relevant software algorithms are detailed. The star scanner is the sole source of inertial attitude reference for this spacecraft. Problem symptoms observed in flight are discussed in terms of effects on spacecraft performance and safety. Sources of thse problems include contributions from flight software idiosyncrasies and inadequate validation of the ground procedures used to identify target stars for use by the autonomous on-board star identification algorithm. Problem fixes (some already implemented and some only proposed) are discussed. A general conclusion is drawn regarding the inherent difficulty of performing simulation tests to validate algorithms which are highly sensitive to external inputs of statistically 'rare' events.

Birth of a megaproject: Political economy of flood control in bangladesh

NASA Astrophysics Data System (ADS)

Boyce, James K.

1990-07-01

A major flood control initiative has been launched in Bangladesh under the coordination of the World Bank. The bank's five-year Action Plan is intended to initiate a long-term investment program, the specifics of which remain to be determined. Long-term proposals under consideration include the construction of massive embankments along the great rivers of the Bangladesh delta. The wisdom of such a “structural solution” to Bangladesh's flood problems can be questioned on economic, environmental, and technical grounds. Regrettably, the decision-making process has not encouraged wide debate on these questions.

Prediction of ground effects on aircraft noise

NASA Technical Reports Server (NTRS)

Pao, S. P.; Wenzel, A. R.; Oncley, P. B.

1978-01-01

A unified method is recommended for predicting ground effects on noise. This method may be used in flyover noise predictions and in correcting static test-stand data to free-field conditions. The recommendation is based on a review of recent progress in the theory of ground effects and of the experimental evidence which supports this theory. It is shown that a surface wave must be included sometimes in the prediction method. Prediction equations are collected conveniently in a single section of the paper. Methods of measuring ground impedance and the resulting ground-impedance data are also reviewed because the recommended method is based on a locally reactive impedance boundary model. Current practice of estimating ground effects are reviewed and consideration is given to practical problems in applying the recommended method. These problems include finite frequency-band filters, finite source dimension, wind and temperature gradients, and signal incoherence.

Permeable pavement and stormwater management systems: a review.

PubMed

Imran, H M; Akib, Shatirah; Karim, Mohamed Rehan

2013-01-01

Uncontrolled stormwater runoff not only creates drainage problems and flash floods but also presents a considerable threat to water quality and the environment. These problems can, to a large extent, be reduced by a type of stormwater management approach employing permeable pavement systems (PPS) in urban, industrial and commercial areas, where frequent problems are caused by intense undrained stormwater. PPS could be an efficient solution for sustainable drainage systems, and control water security as well as renewable energy in certain cases. Considerable research has been conducted on the function of PPS and their improvement to ensure sustainable drainage systems and water quality. This paper presents a review of the use of permeable pavement for different purposes. The paper focuses on drainage systems and stormwater runoff quality from roads, driveways, rooftops and parking lots. PPS are very effective for stormwater management and water reuse. Moreover, geotextiles provide additional facilities to reduce the pollutants from infiltrate runoff into the ground, creating a suitable environment for the biodegradation process. Furthermore, recently, ground source heat pumps and PPS have been found to be an excellent combination for sustainable renewable energy. In addition, this study has identified several gaps in the present state of knowledge on PPS and indicates some research needs for future consideration.

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.

Controlling Emergent Ferromagnetism at Complex Oxide Interfaces

NASA Astrophysics Data System (ADS)

Grutter, Alexander

The emergence of complex magnetic ground states at ABO3 perovskite heterostructure interfaces is among the most promising routes towards highly tunable nanoscale materials for spintronic device applications. Despite recent progress, isolating and controlling the underlying mechanisms behind these emergent properties remains a highly challenging materials physics problems. In particular, generating and tuning ferromagnetism localized at the interface of two non-ferromagnetic materials is of fundamental and technological interest. An ideal model system in which to study such effects is the CaRuO3/CaMnO3 interface, where the constituent materials are paramagnetic and antiferromagnetic in the bulk, respectively. Due to small fractional charge transfer to the CaMnO3 (0.07 e-/Mn) from the CaRuO3, the interfacial Mn ions are in a canted antiferromagnetic state. The delicate balance between antiferromagnetic superexchange and ferromagnetic double exchange results in a magnetic ground state which is extremely sensitive to perturbations. We exploit this sensitivity to achieve control of the magnetic interface, tipping the balance between ferromagnetic and antiferromagnetic interactions through octahedral connectivity modification. Such connectivity effects are typically tightly confined to interfaces, but by targeting a purely interfacial emergent magnetic system, we achieve drastic alterations to the magnetic ground state. These results demonstrate the extreme sensitivity of the magnetic state to the magnitude of the charge transfer, suggesting the potential for direct electric field control. We achieve such electric field control through direct back gating of a CaRuO3/CaMnO3 bilayer. Thus, the CaRuO3/CaMnO3 system provides new insight into how charge transfer, interfacial symmetry, and electric fields may be used to control ferromagnetism at the atomic scale.

Mechanization of and experience with a triplex fly-by-wire backup control system

NASA Technical Reports Server (NTRS)

Lock, W. P.; Petersen, W. R.; Whitman, G. B.

1976-01-01

A redundant three axis analog control system was designed and developed to back up a digital fly by wire control system for an F-8C airplane. The mechanization and operational experience with the backup control system, the problems involved in synchronizing it with the primary system, and the reliability of the system are discussed. The backup control system was dissimilar to the primary system, and it provided satisfactory handling through the flight envelope evaluated. Limited flight tests of a variety of control tasks showed that control was also satisfactory when the backup control system was controlled by a minimum displacement (force) side stick. The operational reliability of the F-8 digital fly by wire control system was satisfactory, with no unintentional downmodes to the backup control system in flight. The ground and flight reliability of the system's components is discussed.

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

Quantum Hamilton equations of motion for bound states of one-dimensional quantum systems

NASA Astrophysics Data System (ADS)

Köppe, J.; Patzold, M.; Grecksch, W.; Paul, W.

2018-06-01

On the basis of Nelson's stochastic mechanics derivation of the Schrödinger equation, a formal mathematical structure of non-relativistic quantum mechanics equivalent to the one in classical analytical mechanics has been established in the literature. We recently were able to augment this structure by deriving quantum Hamilton equations of motion by finding the Nash equilibrium of a stochastic optimal control problem, which is the generalization of Hamilton's principle of classical mechanics to quantum systems. We showed that these equations allow a description and numerical determination of the ground state of quantum problems without using the Schrödinger equation. We extend this approach here to deliver the complete discrete energy spectrum and related eigenfunctions for bound states of one-dimensional stationary quantum systems. We exemplify this analytically for the one-dimensional harmonic oscillator and numerically by analyzing a quartic double-well potential, a model of broad importance in many areas of physics. We furthermore point out a relation between the tunnel splitting of such models and mean first passage time concepts applied to Nelson's diffusion paths in the ground state.

Analysis and control of high-speed wheeled vehicles

NASA Astrophysics Data System (ADS)

Velenis, Efstathios

In this work we reproduce driving techniques to mimic expert race drivers and obtain the open-loop control signals that may be used by auto-pilot agents driving autonomous ground wheeled vehicles. Race drivers operate their vehicles at the limits of the acceleration envelope. An accurate characterization of the acceleration capacity of the vehicle is required. Understanding and reproduction of such complex maneuvers also require a physics-based mathematical description of the vehicle dynamics. While most of the modeling issues of ground-vehicles/automobiles are already well established in the literature, lack of understanding of the physics associated with friction generation results in ad-hoc approaches to tire friction modeling. In this work we revisit this aspect of the overall vehicle modeling and develop a tire friction model that provides physical interpretation of the tire forces. The new model is free of those singularities at low vehicle speed and wheel angular rate that are inherent in the widely used empirical static models. In addition, the dynamic nature of the tire model proposed herein allows the study of dynamic effects such as transients and hysteresis. The trajectory-planning problem for an autonomous ground wheeled vehicle is formulated in an optimal control framework aiming to minimize the time of travel and maximize the use of the available acceleration capacity. The first approach to solve the optimal control problem is using numerical techniques. Numerical optimization allows incorporation of a vehicle model of high fidelity and generates realistic solutions. Such an optimization scheme provides an ideal platform to study the limit operation of the vehicle, which would not be possible via straightforward simulation. In this work we emphasize the importance of online applicability of the proposed methodologies. This underlines the need for optimal solutions that require little computational cost and are able to incorporate real, unpredictable environments. A semi-analytic methodology is developed to generate the optimal velocity profile for minimum time travel along a prescribed path. The semi-analytic nature ensures minimal computational cost while a receding horizon implementation allows application of the methodology in uncertain environments. Extensions to increase fidelity of the vehicle model are finally provided.

Satellite, environmental, and medical information applied to epidemiological monitoring

NASA Technical Reports Server (NTRS)

Roberts, Donald R.; Legters, Llewellyn J.

1991-01-01

Improved communications and space-science technologies, such as remote sensing, offer hope of new, more holistic approaches to combating many arthropod-borne disease problems. The promise offered by these technologies has surfaced at a time when global and national efforts at disease control are in decline. Indeed, these programs seem to be losing ground against the arthropod-borne diseases just as rapidly as we seem to be moving forward in technological development. Given these circumstances, we can only hope that remote sensing and geographic information system (GIS) technologies can be pressed into service to help target the temporal and spatial application of control measures and to help in developing new control strategies.

Scanning Mode Sensor for Detection of Flow Inhomogeneities

NASA Technical Reports Server (NTRS)

Adamovsky, Grigory (Inventor)

1998-01-01

A scanning mode sensor and method is provided for detection of flow inhomogeneities such as shock. The field of use of this invention is ground test control and engine control during supersonic flight. Prior art measuring techniques include interferometry. Schlieren, and shadowgraph techniques. These techniques. however, have problems with light dissipation. The present method and sensor utilizes a pencil beam of energy which is passed through a transparent aperture in a flow inlet in a time-sequential manner so as to alter the energy beam. The altered beam or its effects are processed and can be studied to reveal information about flow through the inlet which can in turn be used for engine control.

Scanning Mode Sensor for Detection of Flow Inhomogeneities

NASA Technical Reports Server (NTRS)

Adamovsky, Grigory (Inventor)

1996-01-01

A scanning mode sensor and method is provided for detection of flow inhomogeneities such as shock. The field of use of this invention is ground test control and engine control during supersonic flight. Prior art measuring techniques include interferometry, Schlieren, and shadowgraph techniques. These techniques, however, have problems with light dissipation. The present method and sensor utilizes a pencil beam of energy which is passed through a transparent aperture in a flow inlet in a time-sequential manner so as to alter the energy beam. The altered beam or its effects are processed and can be studied to reveal information about flow through the inlet which can in turn be used for engine control.

Adiabatic Quantum Computation with Neutral Atoms

NASA Astrophysics Data System (ADS)

Biedermann, Grant

2013-03-01

We are implementing a new platform for adiabatic quantum computation (AQC)[2] based on trapped neutral atoms whose coupling is mediated by the dipole-dipole interactions of Rydberg states. Ground state cesium atoms are dressed by laser fields in a manner conditional on the Rydberg blockade mechanism,[3,4] thereby providing the requisite entangling interactions. As a benchmark we study a Quadratic Unconstrained Binary Optimization (QUBO) problem whose solution is found in the ground state spin configuration of an Ising-like model. In collaboration with Lambert Parazzoli, Sandia National Laboratories; Aaron Hankin, Center for Quantum Information and Control (CQuIC), University of New Mexico; James Chin-Wen Chou, Yuan-Yu Jau, Peter Schwindt, Cort Johnson, and George Burns, Sandia National Laboratories; Tyler Keating, Krittika Goyal, and Ivan Deutsch, Center for Quantum Information and Control (CQuIC), University of New Mexico; and Andrew Landahl, Sandia National Laboratories. This work was supported by the Laboratory Directed Research and Development program at Sandia National Laboratories

Analysis and Ground Testing for Validation of the Inflatable Sunshield in Space (ISIS) Experiment

NASA Technical Reports Server (NTRS)

Lienard, Sebastien; Johnston, John; Adams, Mike; Stanley, Diane; Alfano, Jean-Pierre; Romanacci, Paolo

2000-01-01

The Next Generation Space Telescope (NGST) design requires a large sunshield to protect the large aperture mirror and instrument module from constant solar exposure at its L2 orbit. The structural dynamics of the sunshield must be modeled in order to predict disturbances to the observatory attitude control system and gauge effects on the line of site jitter. Models of large, non-linear membrane systems are not well understood and have not been successfully demonstrated. To answer questions about sunshield dynamic behavior and demonstrate controlled deployment, the NGST project is flying a Pathfinder experiment, the Inflatable Sunshield in Space (ISIS). This paper discusses in detail the modeling and ground-testing efforts performed at the Goddard Space Flight Center to: validate analytical tools for characterizing the dynamic behavior of the deployed sunshield, qualify the experiment for the Space Shuttle, and verify the functionality of the system. Included in the discussion will be test parameters, test setups, problems encountered, and test results.

Ground state sign-changing solutions for fractional Kirchhoff equations in bounded domains

NASA Astrophysics Data System (ADS)

Luo, Huxiao; Tang, Xianhua; Gao, Zu

2018-03-01

We study the existence of ground state sign-changing solutions for the fractional Kirchhoff problem. Under mild assumptions on the nonlinearity, by using some new analytical skills and the non-Nehari manifold method, we prove that the fractional Kirchhoff problem possesses a ground state sign-changing solution ub. Moreover, we show that the energy of ub is strictly larger than twice that of the ground state solutions of Nehari-type. Finally, we establish the convergence property of ub as the parameter b ↘ 0. Our results generalize some results obtained by Shuai [J. Differ. Equations 259, 1256 (2015)] and Tang and Cheng [J. Differ. Equations 261, 2384 (2016)].

Modeling chloride movement in the alluvial aquifer at the Rocky Mountain Arsenal, Colorado

USGS Publications Warehouse

Konikow, Leonard F.

1977-01-01

A solute-transport model that can be used to predict the movement of dissolved chemicals in flowing ground water was applied to a problem of ground-water contamination at the Rocky Mountain Arsenal, near Denver, Colo. The model couples a finite-difference solution to the ground-water flow equation with the method-of-characteristics solution to the solute-transport equation. From 1943 to 1956 liquid industrial wastes containing high chloride concentrations were disposed into unlined ponds at the Arsenal. Wastes seeped out of the unlined disposal ponds and spread for many square miles in the underlying shallow alluvial aquifer. Since 1956 disposal has been into an asphalt-lined reservoir, which contributed to a decline in ground-water contamination by 1972. The simulation model quantitatively integrated the effects of the major factors that controlled changes in chloride concentrations and accurately reproduced the 30-year history of chloride ground-water contamination. Analysis of the simulation results indicates that the geologic framework of the area markedly restricted the transport and dispersion of dissolved chemicals in the alluvium. Dilution, from irrigation recharge and seepage from unlined canals, was an important factor in reducing the level of chloride concentrations downgradient from the Arsenal. Similarly, recharge of uncontaminated water from the unlined ponds since 1956 has helped to dilute and flush the contaminated ground water.

Experience with the EURECA Packet Telemetry and Packet Telecommand system

NASA Technical Reports Server (NTRS)

Sorensen, Erik Mose; Ferri, Paolo

1994-01-01

The European Retrieval Carrier (EURECA) was launched on its first flight on the 31st of July 1992 and retrieved on the 29th of June 1993. EURECA is characterized by several new on-board features, most notably Packet telemetry, and a partial implementation of packet telecommanding, the first ESA packetised spacecraft. Today more than one year after the retrieval the data from the EURECA mission has to a large extent been analysed and we can present some of the interesting results. This paper concentrates on the implementation and operational experience with the EURECA Packet Telemetry and Packet Telecommanding. We already discovered during the design of the ground system that the use of packet telemetry has major impact on the overall design and that processing of packet telemetry may have significant effect on the computer loading and sizing. During the mission a number of problems were identified with the on-board implementation resulting in very strange anomalous behaviors. Many of these problems directly violated basic assumptions for the design of the ground segment adding to the strange behavior. The paper shows that the design of a telemetry packet system should be flexible enough to allow a rapid configuration of the telemetry processing in order to adapt it to the new situation in case of an on-board failure. The experience gained with the EURECA mission control should be used to improve ground systems for future missions.

ADRPM-VII applied to the long-range acoustic detection problem

NASA Technical Reports Server (NTRS)

Shalis, Edward; Koenig, Gerald

1990-01-01

An acoustic detection range prediction model (ADRPM-VII) has been written for IBM PC/AT machines running on the MS-DOS operating system. The software allows the user to predict detection distances of ground combat vehicles and their associated targets when they are involved in quasi-military settings. The program can also calculate individual attenuation losses due to spherical spreading, atmospheric absorption, ground reflection and atmospheric refraction due to temperature and wind gradients while varying parameters effecting the source-receiver problem. The purpose here is to examine the strengths and limitations of ADRPM-VII by modeling the losses due to atmospheric refraction and ground absorption, commonly known as excess attenuation, when applied to the long range detection problem for distances greater than 3 kilometers.

Automatic forest-fire measuring using ground stations and Unmanned Aerial Systems.

PubMed

Martínez-de Dios, José Ramiro; Merino, Luis; Caballero, Fernando; Ollero, Anibal

2011-01-01

This paper presents a novel system for automatic forest-fire measurement using cameras distributed at ground stations and mounted on Unmanned Aerial Systems (UAS). It can obtain geometrical measurements of forest fires in real-time such as the location and shape of the fire front, flame height and rate of spread, among others. Measurement of forest fires is a challenging problem that is affected by numerous potential sources of error. The proposed system addresses them by exploiting the complementarities between infrared and visual cameras located at different ground locations together with others onboard Unmanned Aerial Systems (UAS). The system applies image processing and geo-location techniques to obtain forest-fire measurements individually from each camera and then integrates the results from all the cameras using statistical data fusion techniques. The proposed system has been extensively tested and validated in close-to-operational conditions in field fire experiments with controlled safety conditions carried out in Portugal and Spain from 2001 to 2006.

Automatic Forest-Fire Measuring Using Ground Stations and Unmanned Aerial Systems

PubMed Central

Martínez-de Dios, José Ramiro; Merino, Luis; Caballero, Fernando; Ollero, Anibal

2011-01-01

This paper presents a novel system for automatic forest-fire measurement using cameras distributed at ground stations and mounted on Unmanned Aerial Systems (UAS). It can obtain geometrical measurements of forest fires in real-time such as the location and shape of the fire front, flame height and rate of spread, among others. Measurement of forest fires is a challenging problem that is affected by numerous potential sources of error. The proposed system addresses them by exploiting the complementarities between infrared and visual cameras located at different ground locations together with others onboard Unmanned Aerial Systems (UAS). The system applies image processing and geo-location techniques to obtain forest-fire measurements individually from each camera and then integrates the results from all the cameras using statistical data fusion techniques. The proposed system has been extensively tested and validated in close-to-operational conditions in field fire experiments with controlled safety conditions carried out in Portugal and Spain from 2001 to 2006. PMID:22163958

Potential use of ground-based sensor technologies for weed detection.

PubMed

Peteinatos, Gerassimos G; Weis, Martin; Andújar, Dionisio; Rueda Ayala, Victor; Gerhards, Roland

2014-02-01

Site-specific weed management is the part of precision agriculture (PA) that tries to effectively control weed infestations with the least economical and environmental burdens. This can be achieved with the aid of ground-based or near-range sensors in combination with decision rules and precise application technologies. Near-range sensor technologies, developed for mounting on a vehicle, have been emerging for PA applications during the last three decades. These technologies focus on identifying plants and measuring their physiological status with the aid of their spectral and morphological characteristics. Cameras, spectrometers, fluorometers and distance sensors are the most prominent sensors for PA applications. The objective of this article is to describe-ground based sensors that have the potential to be used for weed detection and measurement of weed infestation level. An overview of current sensor systems is presented, describing their concepts, results that have been achieved, already utilized commercial systems and problems that persist. A perspective for the development of these sensors is given. © 2013 Society of Chemical Industry.

Empirical and pragmatic adequacy of grounded theory: Advancing nurse empowerment theory for nurses' practice.

PubMed

Udod, Sonia A; Racine, Louise

2017-12-01

To draw on the findings of a grounded theory study aimed at exploring how power is exercised in nurse-manager relationships in the hospital setting, this paper examines the empirical and pragmatic adequacy of grounded theory as a methodology to advance the concept of empowerment in the area of nursing leadership and management. The evidence on staff nurse empowerment has highlighted the magnitude of individual and organisational outcomes, but has not fully explicated the micro-level processes underlying how power is exercised, shared or created within the nurse-manager relationship. Although grounded theory is a widely adopted nursing research methodology, it remains less used in nursing leadership because of the dominance of quantitative approaches to research. Grounded theory methodology provides the empirical and pragmatic relevance to inform nursing practice and policy. Grounded theory is a relevant qualitative approach to use in leadership research as it provides a fine and detailed analysis of the process underlying complexity and bureaucracy. Discursive paper. A critical examination of the empirical and pragmatic relevance of grounded theory by (Corbin & Strauss, , ) as a method for analysing and solving problems in nurses' practice is provided. This paper provides evidence to support the empirical and pragmatic adequacy of grounded theory methodology. Although the application of the ontological, epistemological and methodological assumptions of grounded theory is challenging, this methodology is useful to address real-life problems in nursing practice by developing theoretical explanations of nurse empowerment, or lack thereof, in the workplace. Grounded theory represents a relevant methodology to inform nursing leadership research. Grounded theory is anchored in the reality of practice. The strength of grounded theory is to provide results that can be readily applied to clinical practice and policy as they arise from problems that affect practice and that are meaningful to nurses. © 2017 John Wiley & Sons Ltd.

Summary appraisals of the Nation's ground-water resources; Lower Colorado region

USGS Publications Warehouse

Davidson, E.S.

1979-01-01

The potential for greater development of ground water in the southwestern part of the region is constrained by land subsidence, earth cracks, increasing costs of pumping and transportation, and moderate to poor chemical quality of water. More ground water can be developed in the northeastern part of the region, where the major constraint is pumping cost owing to low to moderate well yields and depth to water. Some benefits can be realized everywhere in the region through changes in current use and greater efficiencies of use. Additional supplies may be made available by capture of natural evapotranspiration. Increasing the efficiency of use is possible hydrologically but, in the near term, is more expensive than increasing groundwater development. Decrease of irrigation, change to water-saving methods of irrigation, use of saline water, decrease of per capita public- supply use, and more reuse of water in almost every type of use could help extend the supply and thereby reduce the current rate of ground-water depletion. Financial problems have not yet caused an overall decrease in pumpage, but, locally, operating costs or partial dewatering of the aquifer has eliminated or decreased withdrawal. Current water laws in all States of the region, except Arizona, control or allocate the use of ground water.

GROUND-WATER POLLUTION PROBLEMS IN THE SOUTHEASTERN UNITED STATES

EPA Science Inventory

An evaluation of principal sources of ground-water contamination has been carried out in seven southeastern States--Alabama, Florida, Georgia, Mississippi, North Carolina, South Carolina, and Virginia. Natural ground-water quality is good to excellent, except for the presence of ...

KSC-98pc970

NASA Image and Video Library

1998-08-20

In Firing Room 1 at KSC, Shuttle launch team members put the Shuttle system through an integrated simulation. The control room is set up with software used to simulate flight and ground systems in the launch configuration. A Simulation Team, comprised of KSC engineers, introduce 12 or more major problems to prepare the launch team for worst-case scenarios. Such tests and simulations keep the Shuttle launch team sharp and ready for liftoff. The next liftoff is targeted for Oct. 29

An inventory of aeronautical ground research facilities. Volume 4: Engineering flight simulation facilities

NASA Technical Reports Server (NTRS)

Pirrello, C. J.; Hardin, R. D.; Capelluro, L. P.; Harrison, W. D.

1971-01-01

The general purpose capabilities of government and industry in the area of real time engineering flight simulation are discussed. The information covers computer equipment, visual systems, crew stations, and motion systems, along with brief statements of facility capabilities. Facility construction and typical operational costs are included where available. The facilities provide for economical and safe solutions to vehicle design, performance, control, and flying qualities problems of manned and unmanned flight systems.

A Review of Function Allocation and En Route Separation Assurance

NASA Technical Reports Server (NTRS)

Lewis, Timothy A.; Aweiss, Arwa S.; Guerreiro, Nelson M.; Daiker, Ronald J.

2016-01-01

Today's air traffic control system has reached a limit to the number of aircraft that can be safely managed at the same time. This air traffic capacity bottleneck is a critical problem along the path to modernization for air transportation. The design of the next separation assurance system to address this problem is a cornerstone of air traffic management research today. This report reviews recent work by NASA and others in the areas of function allocation and en route separation assurance. This includes: separation assurance algorithms and technology prototypes; concepts of operations and designs for advanced separation assurance systems; and specific investigations into air-ground and human-automation function allocation.

Studies of some unconventional systems for solving various landing problems. [air cushion landing system

NASA Technical Reports Server (NTRS)

Leland, T. J.; Mcgehee, J. R.; Dreher, R. C.

1981-01-01

Solutions to various landing problems were obtained through unconventional systems. The first, of these is the air cushion landing system, where efforts were concentrated on development of adequate braking and steering systems and an improved understanding of scaling laws and behavior. The second was concentrated on use of a wire brush skid as a drag producing device, which was shown to have good friction coefficients and reasonable wear rates at ground bearing pressures up to 689 kPa and forward speeds up to 80 km/hr. The third showed great promise in an active control landing gear where significant load reductions were possible during landing impact and subsequent rollout.

Generating Safety-Critical PLC Code From a High-Level Application Software Specification

NASA Technical Reports Server (NTRS)

2008-01-01

The benefits of automatic-application code generation are widely accepted within the software engineering community. These benefits include raised abstraction level of application programming, shorter product development time, lower maintenance costs, and increased code quality and consistency. Surprisingly, code generation concepts have not yet found wide acceptance and use in the field of programmable logic controller (PLC) software development. Software engineers at Kennedy Space Center recognized the need for PLC code generation while developing the new ground checkout and launch processing system, called the Launch Control System (LCS). Engineers developed a process and a prototype software tool that automatically translates a high-level representation or specification of application software into ladder logic that executes on a PLC. All the computer hardware in the LCS is planned to be commercial off the shelf (COTS), including industrial controllers or PLCs that are connected to the sensors and end items out in the field. Most of the software in LCS is also planned to be COTS, with only small adapter software modules that must be developed in order to interface between the various COTS software products. A domain-specific language (DSL) is a programming language designed to perform tasks and to solve problems in a particular domain, such as ground processing of launch vehicles. The LCS engineers created a DSL for developing test sequences of ground checkout and launch operations of future launch vehicle and spacecraft elements, and they are developing a tabular specification format that uses the DSL keywords and functions familiar to the ground and flight system users. The tabular specification format, or tabular spec, allows most ground and flight system users to document how the application software is intended to function and requires little or no software programming knowledge or experience. A small sample from a prototype tabular spec application is shown.

Method development at Nordic School of Public Health NHV: Phenomenology and Grounded Theory.

PubMed

Strandmark, Margaretha

2015-08-01

Qualitative methods such as phenomenology and grounded theory have been valuable tools in studying public health problems. A description and comparison of these methods. Phenomenology emphasises an inside perspective in form of consciousness and subjectively lived experiences, whereas grounded theory emanates from the idea that interactions between people create new insights and knowledge. Fundamental aspects of phenomenology include life world, consciousness, phenomenological reduction and essence. Significant elements in grounded theory are coding, categories and core categories, which develop a theory. There are differences in the philosophical approach, the name of the concept and the systematic tools between the methods. Thus, the phenomenological method is appropriate when studying emotional and existential research problems, and grounded theory is a method more suited to investigate processes. © 2015 the Nordic Societies of Public Health.

An intelligent position-specific training system for mission operations

NASA Technical Reports Server (NTRS)

Schneider, M. P.

1992-01-01

Marshall Space Flight Center's (MSFC's) payload ground controller training program provides very good generic training; however, ground controller position-specific training can be improved by including position-specific training systems in the training program. This report explains why MSFC needs to improve payload ground controller position-specific training. The report describes a generic syllabus for position-specific training systems, a range of system designs for position-specific training systems, and a generic development process for developing position-specific training systems. The report also describes a position-specific training system prototype that was developed for the crew interface coordinator payload operations control center ground controller position. The report concludes that MSFC can improve the payload ground controller training program by incorporating position-specific training systems for each ground controller position; however, MSFC should not develop position-specific training systems unless payload ground controller position experts will be available to participate in the development process.

[Development of New Mathematical Methodology in Air Traffic Control for the Analysis of Hybrid Systems

NASA Technical Reports Server (NTRS)

Hermann, Robert

1997-01-01

The aim of this research is to develop new mathematical methodology for the analysis of hybrid systems of the type involved in Air Traffic Control (ATC) problems. Two directions of investigation were initiated. The first used the methodology of nonlinear generalized functions, whose mathematical foundations were initiated by Colombeau and developed further by Oberguggenberger; it has been extended to apply to ordinary differential. Systems of the type encountered in control in joint work with the PI and M. Oberguggenberger. This involved a 'mixture' of 'continuous' and 'discrete' methodology. ATC clearly involves mixtures of two sorts of mathematical problems: (1) The 'continuous' dynamics of a standard control type described by ordinary differential equations (ODE) of the form: {dx/dt = f(x, u)} and (2) the discrete lattice dynamics involved of cellular automata. Most of the CA literature involves a discretization of a partial differential equation system of the type encountered in physics problems (e.g. fluid and gas problems). Both of these directions requires much thinking and new development of mathematical fundamentals before they may be utilized in the ATC work. Rather than consider CA as 'discretization' of PDE systems, I believe that the ATC applications will require a completely different and new mathematical methodology, a sort of discrete analogue of jet bundles and/or the sheaf-theoretic techniques to topologists. Here too, I have begun work on virtually 'virgin' mathematical ground (at least from an 'applied' point of view) which will require considerable preliminary work.

Application of oil spill model to marine pollution and risk control problems

NASA Astrophysics Data System (ADS)

Aseev, Nikita; Agoshkov, Valery; Sheloput, Tatyana

2017-04-01

Oil transportation by sea induces challenging problems of environmental control. Millions of tonnes of oil are yearly released during routine ship operations, not to mention vast spills due to different accidents (e.g. tanker collisions, grounding, etc.). Oil pollution is dangerous to marine organisms such as plants, fish and mammals, leading to widespread damage to our planet. In turn, fishery and travel agencies can lose money and clients, and ship operators are obliged to pay huge penalties for environmental pollution. In this work we present the method of accessing oil pollution of marine environment using recently developed oil spill model. The model describes basic processes of the oil slick evolution: oil transport due to currents, drift under the action of wind, spreading on the surface, evaporation, emulsification and dispersion. Such parameters as slick location, mass, density of oil, water content, viscosity and density of "water-in-oil" emulsion can be calculated. We demonstrate how to apply the model to damage calculation problems using a concept of average damage to particular marine area. We also formulate the problem of oil spill risk control, when some accident parameters are not known, but their probability distribution is given. We propose a new algorithm to solve such problems and show results of our model simulations. The work can be interesting to broad environmental, physics and mathematics community. The work is supported by Russian Foundation for Basic Research grant 16-31-00510.

NASA's aviation safety research and technology program

NASA Technical Reports Server (NTRS)

Fichtl, G. H.

1977-01-01

Aviation safety is challenged by the practical necessity of compromising inherent factors of design, environment, and operation. If accidents are to be avoided these factors must be controlled to a degree not often required by other transport modes. The operational problems which challenge safety seem to occur most often in the interfaces within and between the design, the environment, and operations where mismatches occur due to ignorance or lack of sufficient understanding of these interactions. Under this report the following topics are summarized: (1) The nature of operating problems, (2) NASA aviation safety research, (3) clear air turbulence characterization and prediction, (4) CAT detection, (5) Measurement of Atmospheric Turbulence (MAT) Program, (6) Lightning, (7) Thunderstorm gust fronts, (8) Aircraft ground operating problems, (9) Aircraft fire technology, (10) Crashworthiness research, (11) Aircraft wake vortex hazard research, and (12) Aviation safety reporting system.

Numerical modelling of GPR ground-matching enhancement by a chirped multilayer structure - output of cooperation within COST Action TU1208

NASA Astrophysics Data System (ADS)

Baghdasaryan, Hovik V.; Knyazyan, Tamara M.; Hovhannisyan, Tamara. T.; Marciniak, Marian; Pajewski, Lara

2016-04-01

As is well know, Ground Penetrating Radar (GPR) is an electromagnetic technique for the detection and imaging of buried objects, with resolution ranging from centimeters to few meters [1, 2]. Though this technique is mature enough and different types of GPR devices are already in use, some problems are still waiting for their solution [3]. One of them is to achieve a better matching of transmitting GPR antenna to the ground, that will increase the signal penetration depth and the signal/noise ratio at the receiving end. In the current work, a full-wave electromagnetic modelling of the interaction of a plane wave with a chirped multilayered structure on the ground is performed, via numerical simulation. The method of single expression is used, which is a suitable technique for multi-boundary problems solution [4, 5]. The considered multilayer consists of two different dielectric slabs of low and high permittivity, where the highest value of permittivity doesn't exceed the permittivity of the ground. The losses in the ground are suitably taken into account. Two types of multilayers are analysed. Numerical results are obtained for the reflectance from the structure, as well as for the distributions of electric field components and power flow density in both the considered structures and the ground. The obtained results indicate that, for a better matching with the ground, the layer closer to the ground should be the high-permittivity one. Acknowledgement This work benefited from networking activities carried out within the EU funded COST Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar" (www.GPRadar.eu, www.cost.eu). Part of this work was developed during the Short-Term Scientific Mission COST-STSM-TU1208-25016, carried out by Prof. Baghdasaryan in the National Institute of Telecommunications in Warsaw, Poland. References [1] H. M. Jol. Ground Penetrating Radar: Theory and Applications. Elsevier, 2009. 509 pp. [2] R. Persico. Introduction to Ground Penetrating Radar. IEEE Press, Wiley, 2014. 368 pp. [3] A. Benedetto, L. Pajewski. Civil Engineering Applications of Ground Penetrating Radar. Springer, 2015. 371 pp. [4] H.V. Baghdasaryan, T.M. Knyazyan, "Problem of Plane EM-Wave Self-action in Multilayer Structure: an Exact Solution", Optical and Quantum Electronics, vol. 31, 1999, pp. 1059-1072. [5] H.V. Baghdasaryan, "Basics of the Method of Single Expression: New Approach for Solving Boundary Problems in Classical Electrodynamics", Yerevan, Chartaraget, 2013.

Undermining subsistence: Barren-ground caribou in a “tragedy of open access”

PubMed Central

Parlee, Brenda L.; Sandlos, John; Natcher, David C.

2018-01-01

Sustaining arctic/subarctic ecosystems and the livelihoods of northern Indigenous peoples is an immense challenge amid increasing resource development. The paper describes a “tragedy of open access” occurring in Canada’s north as governments open up new areas of sensitive barren-ground caribou habitat to mineral resource development. Once numbering in the millions, barren-ground caribou populations (Rangifer tarandus groenlandicus/Rangifer tarandus granti) have declined over 70% in northern Canada over the last two decades in a cycle well understood by northern Indigenous peoples and scientists. However, as some herds reach critically low population levels, the impacts of human disturbance have become a major focus of debate in the north and elsewhere. A growing body of science and traditional knowledge research points to the adverse impacts of resource development; however, management efforts have been almost exclusively focused on controlling the subsistence harvest of northern Indigenous peoples. These efforts to control Indigenous harvesting parallel management practices during previous periods of caribou population decline (for example, 1950s) during which time governments also lacked evidence and appeared motivated by other values and interests in northern lands and resources. As mineral resource development advances in northern Canada and elsewhere, addressing this “science-policy gap” problem is critical to the sustainability of both caribou and people. PMID:29503864

Approximate ground states of the random-field Potts model from graph cuts

NASA Astrophysics Data System (ADS)

Kumar, Manoj; Kumar, Ravinder; Weigel, Martin; Banerjee, Varsha; Janke, Wolfhard; Puri, Sanjay

2018-05-01

While the ground-state problem for the random-field Ising model is polynomial, and can be solved using a number of well-known algorithms for maximum flow or graph cut, the analog random-field Potts model corresponds to a multiterminal flow problem that is known to be NP-hard. Hence an efficient exact algorithm is very unlikely to exist. As we show here, it is nevertheless possible to use an embedding of binary degrees of freedom into the Potts spins in combination with graph-cut methods to solve the corresponding ground-state problem approximately in polynomial time. We benchmark this heuristic algorithm using a set of quasiexact ground states found for small systems from long parallel tempering runs. For a not-too-large number q of Potts states, the method based on graph cuts finds the same solutions in a fraction of the time. We employ the new technique to analyze the breakup length of the random-field Potts model in two dimensions.

Computational solution of atmospheric chemistry problems

NASA Technical Reports Server (NTRS)

Jafri, J.; Ake, R. L.

1986-01-01

Extensive studies were performed on problems of interest in atmospheric chemistry. In addition to several minor projects, four major projects were performed and described (theoretical studies of ground and low-lying excited states of ClO2; ground and excited state potential energy surfaces of the methyl peroxy radical; electronic states ot the FO radical; and theoretical studies S02 (H2O) (sub n)).

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.

Information needs related to extension service and community outreach.

PubMed

Bottcher, Robert W

2003-06-01

Air quality affects everyone. Some people are affected by air quality impacts, regulations, and technological developments in several ways. Stakeholders include the medical community, ecologists, government regulators, industries, technology providers, academic professionals, concerned citizens, the news media, and elected officials. Each of these groups may perceive problems and opportunities differently, but all need access to information as it is developed. The diversity and complexity of air quality problems contribute to the challenges faced by extension and outreach professionals who must communicate with stakeholders having diverse backgrounds. Gases, particulates, biological aerosols, pathogens, and odors all require expensive and relatively complex technology to measure and control. Economic constraints affect the ability of regulators and others to measure air quality, and industry and others to control it. To address these challenges, while communicating air quality research results and concepts to stakeholders, three areas of information needs are evident. (1) A basic understanding of the fundamental concepts regarding air pollutants and their measurement and control is needed by all stakeholders; the Extension Specialist, to be effective, must help people move some distance up the learning curve. (2) Each problem or set of problems must be reasonably well defined since comprehensive solution of all problems simultaneously may not be feasible; for instance, the solution of an odor problem associated with animal production may not address atmospheric effects due to ammonia emissions. (3) The integrity of the communication process must be preserved by avoiding prejudice and protectionism; although stakeholders may seek to modify information to enhance their interests, extension and outreach professionals must be willing to present unwelcome information or admit to a lack of information. A solid grounding in fundamental concepts, careful and fair problem definition, and a resolute commitment to integrity and credibility will enable effective communication of air quality information to and among diverse stakeholders.

Grounded Classification: Grounded Theory and Faceted Classification.

ERIC Educational Resources Information Center

Star, Susan Leigh

1998-01-01

Compares the qualitative method of grounded theory (GT) with Ranganathan's construction of faceted classifications (FC) in library and information science. Both struggle with a core problem--the representation of vernacular words and processes, empirically discovered, which will, although ethnographically faithful, be powerful beyond the single…

Stochastic model of the NASA/MSFC ground facility for large space structures with uncertain parameters: The maximum entropy approach, part 2

NASA Technical Reports Server (NTRS)

Hsia, Wei Shen

1989-01-01

A validated technology data base is being developed in the areas of control/structures interaction, deployment dynamics, and system performance for Large Space Structures (LSS). A Ground Facility (GF), in which the dynamics and control systems being considered for LSS applications can be verified, was designed and built. One of the important aspects of the GF is to verify the analytical model for the control system design. The procedure is to describe the control system mathematically as well as possible, then to perform tests on the control system, and finally to factor those results into the mathematical model. The reduction of the order of a higher order control plant was addressed. The computer program was improved for the maximum entropy principle adopted in Hyland's MEOP method. The program was tested against the testing problem. It resulted in a very close match. Two methods of model reduction were examined: Wilson's model reduction method and Hyland's optimal projection (OP) method. Design of a computer program for Hyland's OP method was attempted. Due to the difficulty encountered at the stage where a special matrix factorization technique is needed in order to obtain the required projection matrix, the program was successful up to the finding of the Linear Quadratic Gaussian solution but not beyond. Numerical results along with computer programs which employed ORACLS are presented.

F-16XL ship #1 (#849) during first flight of the Digital Flight Control System (DFCS)

NASA Technical Reports Server (NTRS)

1997-01-01

After completing its first flight with the Digital Flight Control System on December 16, 1997, the F-16XL #1 aircraft began a series of envelope expansion flights. On January 27 and 29, 1998, it successfully completed structural clearance tests, as well as most of the load testing Only flights at Mach 1.05 at 10,000 feet, Mach 1.1 at 15,000 feet, and Mach 1.2 at 20,000 feet remained. During the next flight, on February 4, an instrumentation problem cut short the planned envelope expansion tests. After the problem was corrected, the F-16XL returned to flight status, and on February 18 and 20, flight control and evaluation flights were made. Two more research flights were planned for the following week, but another problem appeared. During the ground start up, project personnel noticed that the leading edge flap moved without being commanded. The Digital Flight Control Computer was sent to the Lockheed-Martin facility at Fort Worth, where the problem was traced to a defective chip in the computer. After it was replaced, the F-16XL #1 flew a highly successful flight controls and handling qualities evaluation flight on March 26, clearing the way for the final tests. The final limited loads expansion flight occurred on March 31, and was fully successful. As a result, the on-site Lockheed-Martin loads engineer cleared the aircraft to Mach 1.8. The remaining two handling qualities and flight control evaluation flights were both made on April 3, 1998. These three flights concluded the flight test portion of the DFCS upgrade.

NASA/ESA CV-990 Spacelab Simulation (ASSESS 2)

NASA Technical Reports Server (NTRS)

1977-01-01

Cost effective techniques for addressing management and operational activities on Spacelab were identified and analyzed during a ten day NASA-ESA cooperative mission with payload and flight responsibilities handled by the organization assigned for early Spacelabs. Topics discussed include: (1) management concepts and interface relationships; (2) experiment selection; (3) hardware development; (4) payload integration and checkout; (5) selection and training of mission specialists and payload specialists; (6) mission control center/payload operations control center interactions with ground and flight problems; (7) real time interaction during flight between principal investigators and the mission specialist/payload specialist flight crew; and (8) retrieval of scientific data and its analysis.

Expansion of flight simulator capability for study and solution of aircraft directional control problems on runways

NASA Technical Reports Server (NTRS)

Kibbee, G. W.

1978-01-01

The development, evaluation, and evaluation results of a DC-9-10 runway directional control simulator are described. An existing wide bodied flight simulator was modified to this aircraft configuration. The simulator was structured to use either two of antiskid simulations; (1) an analog mechanization that used aircraft hardware; or (2) a digital software simulation. After the simulation was developed it was evaluated by 14 pilots who made 818 simulated flights. These evaluations involved landings, rejected takeoffs, and various ground maneuvers. Qualitatively most pilots evaluated the simulator as realistic with good potential especially for pilot training for adverse runway conditions.

Perception, planning, and control for walking on rugged terrain

NASA Technical Reports Server (NTRS)

Simmons, Reid; Krotkov, Eric

1991-01-01

The CMU Planetary Rover project is developing a six-legged walking robot capable of autonomously navigating, exploring, and acquiring samples in rugged, unknown environments. To gain experience with the problems involved in walking on rugged terrain, a full-scale prototype leg was built and mounted on a carriage that rolls along overhead rails. Issues addressed in developing the software system to autonomously walk the leg through rugged terrain are described. In particular, the insights gained into perceiving and modeling rugged terrain, controlling the legged mechanism, interacting with the ground, choosing safe yet effective footfalls, and planning efficient leg moves through space are described.

Advancing adolescent maternal development: a grounded theory.

PubMed

Atkinson, Leah D; Peden-McAlpine, Cynthia J

2014-01-01

This paper reports a substantive grounded theory called the theory of Advancing Adolescent Maternal Development. A grounded theory approach was used. Thirty public health nurses working with adolescent clients in a state public health nurse home visiting program volunteered to participate in this study. The basic social psychological problem that emerged from the data was incomplete and at risk adolescent maternal development. Social support and public health nursing interventions are central in the problem resolution process which occurs in stages. Study results can be used to inform the nursing care of pregnant and parenting adolescents. © 2014.

Ground-water conditions in the central Virgin River basin, Utah

USGS Publications Warehouse

Cordova, R.M.; Sandberg, G.W.; McConkie, Wilson

1972-01-01

Water-rights problems have occurred in the central Virgin River basin and are expected to increase as development of the water resources increases. The Utah State Engineer needs a basic knowledge of ground-water conditions and of the relation of ground water to surface water as a first step to understanding and resolving the problems. Accordingly, the State Engineer requested the U. S. Geological Survey to make a ground-water investigation of the central Virgin River basin as part of the Statewide cooperative agreement with the Utah Department of Natural Resources. The investigation was begun July 1, 1968, and fieldwork was completed in August 1970. Detailed information was obtained for the principal aquifers and for recharge, movement, discharge, storage, utilization, and chemical quality of ground water. A progress report (Cordova, Sandberg, and McConkie, 1970) describes the general findings in the first year of the investigation.

MODFLOW-2005, the U.S. Geological Survey modular ground-water model - documentation of shared node local grid refinement (LGR) and the boundary flow and head (BFH) package

USGS Publications Warehouse

Mehl, Steffen W.; Hill, Mary C.

2006-01-01

This report documents the addition of shared node Local Grid Refinement (LGR) to MODFLOW-2005, the U.S. Geological Survey modular, transient, three-dimensional, finite-difference ground-water flow model. LGR provides the capability to simulate ground-water flow using one block-shaped higher-resolution local grid (a child model) within a coarser-grid parent model. LGR accomplishes this by iteratively coupling two separate MODFLOW-2005 models such that heads and fluxes are balanced across the shared interfacing boundary. LGR can be used in two-and three-dimensional, steady-state and transient simulations and for simulations of confined and unconfined ground-water systems. Traditional one-way coupled telescopic mesh refinement (TMR) methods can have large, often undetected, inconsistencies in heads and fluxes across the interface between two model grids. The iteratively coupled shared-node method of LGR provides a more rigorous coupling in which the solution accuracy is controlled by convergence criteria defined by the user. In realistic problems, this can result in substantially more accurate solutions and require an increase in computer processing time. The rigorous coupling enables sensitivity analysis, parameter estimation, and uncertainty analysis that reflects conditions in both model grids. This report describes the method used by LGR, evaluates LGR accuracy and performance for two- and three-dimensional test cases, provides input instructions, and lists selected input and output files for an example problem. It also presents the Boundary Flow and Head (BFH) Package, which allows the child and parent models to be simulated independently using the boundary conditions obtained through the iterative process of LGR.

KSC-98pc969

NASA Image and Video Library

1998-08-19

KENNEDY SPACE CENTER, FLA. -- In Firing Room 1 at KSC, Shuttle launch team members put the Shuttle system through an integrated simulation. The control room is set up with software used to simulate flight and ground systems in the launch configuration. A Simulation Team, comprisING KSC engineers, introduce 12 or more major problems to prepare the launch team for worst-case scenarios. Such tests and simulations keep the Shuttle launch team sharp and ready for liftoff. The next liftoff is targeted for Oct. 29.

KSC-98pc971

NASA Image and Video Library

1998-08-20

KENNEDY SPACE CENTER, FLA. -- In Firing Room 1 at KSC, Shuttle launch team members put the Shuttle system through an integrated simulation. The control room is set up with software used to simulate flight and ground systems in the launch configuration. A Simulation Team, comprising KSC engineers, introduce 12 or more major problems to prepare the launch team for worst-case scenarios. Such tests and simulations keep the Shuttle launch team sharp and ready for liftoff. The next liftoff is targeted for Oct. 29

A Ground-Up Model for Gun Violence Reduction: A Community-Based Public Health Approach.

PubMed

Byrdsong, T Rashad; Devan, Angela; Yamatani, Hide

2016-01-01

The suggested strategy for the reduction of violence is to collaboratively address the problem, based on an intervention system focused on prevention, rehabilitation, and development. This strategy is capable of engaging community residents in positive ways, and it empowers them to take ownership and sustain much-needed resident commitments to achieve long-term public safety. The community residents largely insist that over-reliance on law enforcement to control violence invites further affliction among Black youth and adults.

MS Thomas on middeck with TIPS messages

NASA Image and Video Library

2016-08-12

STS083-309-003 (4-8 April 1997) --- Astronaut Donald A. Thomas, mission specialist, checks a fresh delivery of messages from ground controllers onboard the Earth-orbiting Space Shuttle Columbia. The Thermal Impulse Imaging System (TIPS) is located on the mid deck of Columbia. Thomas, along with four other NASA astronauts and two payload specialists supporting the Microgravity Sciences Laboratory (MSL-1) mission were less than a fourth of the way through a scheduled 16-day flight when a power problem cut short their planned stay.

The KSC Simulation Team practices for contingencies in Firing Room 1

NASA Technical Reports Server (NTRS)

1998-01-01

In Firing Room 1 at KSC, Shuttle launch team members put the Shuttle system through an integrated simulation. The control room is set up with software used to simulate flight and ground systems in the launch configuration. A Simulation Team, comprised of KSC engineers, introduce 12 or more major problems to prepare the launch team for worst-case scenarios. Such tests and simulations keep the Shuttle launch team sharp and ready for liftoff. The next liftoff is targeted for Oct. 29.

Field Application of a Permeable Reactive Barrier for Treatment of Arsenic in Ground Water

EPA Science Inventory

Contamination of ground-water resources by arsenic is a widespread environmental problem; consequently, there is an escalating need for developments and improvements of remedial technologies to effectively manage arsenic contamination in ground water and soils. In June 2005, a 9...

AN IN-SITU PERMEABLE REACTIVE BARRIER FOR THE TREATMENT OF ARSENIC IN GROUND WATER

EPA Science Inventory

Contamination of ground-water resources by arsenic is a widespread environmental problem; consequently, there is an escalating need for developments and improvements of remedial technologies to effectively manage arsenic contamination in ground water and soils. In June 2005, a 7 ...

AN IN-SITU PERMEABLE REACTIVE BARRIER FOR THE TREATMENT OF ARSENIC IN GROUND WATER

EPA Science Inventory

Contamination of ground-water resources by arsenic is a widespread environmental problem; consequently, there is an escalating need for developments and improvements of remedial technologies to effectively manage arsenic contamination in ground water and soils. In June 2005, a 7...

THE EMERGING RELATIONSHIP BETWEEN GROUND LEVEL OZONE AND LANDSCAPE CHARACTERISTICS

EPA Science Inventory

One of the most serious environmental health problems facing our society is that of poor air quality caused primarily by the formation of ground level ozone. Although natural ozone is beneficial in the upper atmosphere as a filter for ultraviolet radiation, ground- level ozone is...

The Ground Flash Fraction Retrieval Algorithm Employing Differential Evolution: Simulations and Applications

NASA Technical Reports Server (NTRS)

Koshak, William; Solakiewicz, Richard

2012-01-01

The ability to estimate the fraction of ground flashes in a set of flashes observed by a satellite lightning imager, such as the future GOES-R Geostationary Lightning Mapper (GLM), would likely improve operational and scientific applications (e.g., severe weather warnings, lightning nitrogen oxides studies, and global electric circuit analyses). A Bayesian inversion method, called the Ground Flash Fraction Retrieval Algorithm (GoFFRA), was recently developed for estimating the ground flash fraction. The method uses a constrained mixed exponential distribution model to describe a particular lightning optical measurement called the Maximum Group Area (MGA). To obtain the optimum model parameters (one of which is the desired ground flash fraction), a scalar function must be minimized. This minimization is difficult because of two problems: (1) Label Switching (LS), and (2) Parameter Identity Theft (PIT). The LS problem is well known in the literature on mixed exponential distributions, and the PIT problem was discovered in this study. Each problem occurs when one allows the numerical minimizer to freely roam through the parameter search space; this allows certain solution parameters to interchange roles which leads to fundamental ambiguities, and solution error. A major accomplishment of this study is that we have employed a state-of-the-art genetic-based global optimization algorithm called Differential Evolution (DE) that constrains the parameter search in such a way as to remove both the LS and PIT problems. To test the performance of the GoFFRA when DE is employed, we applied it to analyze simulated MGA datasets that we generated from known mixed exponential distributions. Moreover, we evaluated the GoFFRA/DE method by applying it to analyze actual MGAs derived from low-Earth orbiting lightning imaging sensor data; the actual MGA data were classified as either ground or cloud flash MGAs using National Lightning Detection Network[TM] (NLDN) data. Solution error plots are provided for both the simulations and actual data analyses.

Predicting ground-water movement in large mine spoil areas in the Appalachian Plateau

USGS Publications Warehouse

Wunsch, D.R.; Dinger, J.S.; Graham, C.D.R.

1999-01-01

Spoil created by surface mining can accumulate large quantities of ground-water, which can create geotechnical or regulatory problems, as well as flood active mine pits. A current study at a large (4.1 km2), thick, (up to 90 m) spoil body in eastern Kentucky reveals important factors that control the storage and movement of water. Ground-water recharge occurs along the periphery of the spoil body where surface-water drainage is blocked, as well as from infiltration along the spoil-bedrock contact, recharge from adjacent bedrock, and to a minor extent, through macropores at the spoil's surface. Based on an average saturated thickness of 6.4 m for all spoil wells, and assuming an estimated porosity of 20%, approximately 5.2 x 106 m3 of water is stored within the existing 4.1 km2 of reclaimed spoil. A conceptual model of ground-water flow, based on data from monitoring wells, dye-tracing data, discharge from springs and ponds, hydraulic gradients, chemical data, field reconnaissance, and aerial photographs indicate that three distinct but interconnected saturated zones have been established: one in the spoil's interior, and others in the valley fills that surround the main spoil body at lower elevations. Ground-water movement is sluggish in the spoil's interior, but moves quickly through the valley fills. The conceptual model shows that a prediction of ground-water occurrence, movement, and quality can be made for active or abandoned spoil areas if all or some of the following data are available: structural contour of the base of the lowest coal seam being mined, pre-mining topography, documentation of mining methods employed throughout the mine, overburden characteristics, and aerial photographs of mine progression.Spoil created by surface mining can accumulate large quantities of ground-water, which can create geotechnical or regulatory problems, as well as flood active mine pits. A current study at a large (4.1 km2), thick, (up to 90 m) spoil body in eastern Kentucky reveals important factors that control the storage and movement of water. Ground-water recharge occurs along the periphery of the spoil body where surface-water drainage is blocked, as well as from infiltration along the spoil-bedrock contact, recharge from adjacent bedrock, and to a minor extent, through macropores at the spoil's surface. Based on an average saturated thickness of 6.4 m for all spoil wells, and assuming an estimated porosity of 20%, approximately 5.2 ?? 106 m3 of water is stored within the existing 4.1 km2 of reclaimed spoil. A conceptual model of ground-water flow, based on data from monitoring wells, dye-tracing data, discharge from springs and ponds, hydraulic gradients, chemical data, field reconnaissance, and aerial photographs indicate that three distinct but interconnected saturated zones have been established: one in the spoil's interior, and others in the valley fills that surround the main spoil body at lower elevations. Ground-water movement is sluggish in the spoil's interior, but moves quickly through the valley fills. The conceptual model shows that a prediction of ground-water occurrence, movement, and quality can be made for active or abandoned spoil areas if all or some of the following data are available: structural contour of the base of the lowest coal seam being mined, pre-mining topography, documentation of mining methods employed throughout the mine, overburden characteristics, and aerial photographs of mine progression.

Experimental evaluation of model predictive control and inverse dynamics control for spacecraft proximity and docking maneuvers

NASA Astrophysics Data System (ADS)

Virgili-Llop, Josep; Zagaris, Costantinos; Park, Hyeongjun; Zappulla, Richard; Romano, Marcello

2018-03-01

An experimental campaign has been conducted to evaluate the performance of two different guidance and control algorithms on a multi-constrained docking maneuver. The evaluated algorithms are model predictive control (MPC) and inverse dynamics in the virtual domain (IDVD). A linear-quadratic approach with a quadratic programming solver is used for the MPC approach. A nonconvex optimization problem results from the IDVD approach, and a nonlinear programming solver is used. The docking scenario is constrained by the presence of a keep-out zone, an entry cone, and by the chaser's maximum actuation level. The performance metrics for the experiments and numerical simulations include the required control effort and time to dock. The experiments have been conducted in a ground-based air-bearing test bed, using spacecraft simulators that float over a granite table.

Spin systems and Political Districting Problem

NASA Astrophysics Data System (ADS)

Chou, Chung-I.; Li, Sai-Ping

2007-03-01

The aim of the Political Districting Problem is to partition a territory into electoral districts subject to some constraints such as contiguity, population equality, etc. In this paper, we apply statistical physics methods to Political Districting Problem. We will show how to transform the political problem to a spin system, and how to write down a q-state Potts model-like energy function in which the political constraints can be written as interactions between sites or external fields acting on the system. Districting into q voter districts is equivalent to finding the ground state of this q-state Potts model. Searching for the ground state becomes an optimization problem, where optimization algorithms such as the simulated annealing method and Genetic Algorithm can be employed here.

Exposure to microgravity for 30 days onboard Bion M1 caused muscle atrophy and impaired regeneration in murine femoral Quadriceps

NASA Astrophysics Data System (ADS)

Radugina, E. A.; Almeida, E. A. C.; Blaber, E.; Poplinskaya, V. A.; Markitantova, Y. V.; Grigoryan, E. N.

2018-02-01

Mechanical unloading in microgravity during spaceflight is known to cause muscular atrophy, changes in muscle fiber composition, gene expression, and reduction in regenerative muscle growth. Although some limited data exists for long-term effects of microgravity in human muscle, these processes have mostly been studied in rodents for short periods of time. Here we report on how long-term (30-day long) mechanical unloading in microgravity affects murine muscles of the femoral Quadriceps group. To conduct these studies we used muscle tissue from 6 microgravity mice, in comparison to habitat (7), and vivarium (14) ground control mice from the NASA Biospecimen Sharing Program conducted in collaboration with the Institute for Biomedical Problems of the Russian Academy of Sciences, during the Russian Bion M1 biosatellite mission in 2013. Muscle histomorphology from microgravity specimens showed signs of extensive atrophy and regenerative hypoplasia relative to ground controls. Specifically, we observed a two-fold decrease in the number of myonuclei, compared to vivarium and ground controls, and central location of myonuclei, low density of myofibers in the tissue, and of myofibrils within a fiber, as well as fragmentation and swelling of myofibers. Despite obvious atrophy, muscle regeneration nevertheless appeared to have continued after 30 days in microgravity as evidenced by thin and short newly formed myofibers. Many of them, however, showed evidence of apoptotic cells and myofibril degradation, suggesting that long-term unloading in microgravity may affect late stages of myofiber differentiation. Ground asynchronous and vivarium control animals demonstrated normal, well-developed tissue structure with sufficient blood and nerve supply and evidence of regenerative formation of new myofibers free of apoptotic nuclei. Regenerative activity of satellite cells in muscles was observed both in microgravity and ground control groups, using Pax7 and Myogenin immunolocalization, as well as Myogenin expression analysis. In addition, we have detected positive nuclear immunolocalization of c-Jun and c-Myc proteins indicating their sensitivity to changes in gravitational loading in a given model. In summary, long-term spaceflight in microgravity caused significant atrophy and degeneration of the femoral Quadriceps muscle group, and it may interfere with muscle regenerative processes by inducing apoptosis in newly-formed myofibrils during their differentiation phase.

Improving Dorsal Stream Function in Dyslexics by Training Figure/Ground Motion Discrimination Improves Attention, Reading Fluency, and Working Memory.

PubMed

Lawton, Teri

2016-01-01

There is an ongoing debate about whether the cause of dyslexia is based on linguistic, auditory, or visual timing deficits. To investigate this issue three interventions were compared in 58 dyslexics in second grade (7 years on average), two targeting the temporal dynamics (timing) of either the auditory or visual pathways with a third reading intervention (control group) targeting linguistic word building. Visual pathway training in dyslexics to improve direction-discrimination of moving test patterns relative to a stationary background (figure/ground discrimination) significantly improved attention, reading fluency, both speed and comprehension, phonological processing, and both auditory and visual working memory relative to controls, whereas auditory training to improve phonological processing did not improve these academic skills significantly more than found for controls. This study supports the hypothesis that faulty timing in synchronizing the activity of magnocellular with parvocellular visual pathways is a fundamental cause of dyslexia, and argues against the assumption that reading deficiencies in dyslexia are caused by phonological deficits. This study demonstrates that visual movement direction-discrimination can be used to not only detect dyslexia early, but also for its successful treatment, so that reading problems do not prevent children from readily learning.

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.

Development and Testing of a Two-UAV Communication Relay System.

PubMed

Li, Boyang; Jiang, Yifan; Sun, Jingxuan; Cai, Lingfeng; Wen, Chih-Yung

2016-10-13

In the development of beyond-line-of-sight (BLOS) Unmanned Aerial Vehicle (UAV) systems, communication between the UAVs and the ground control station (GCS) is of critical importance. The commonly used economical wireless modules are restricted by the short communication range and are easily blocked by obstacles. The use of a communication relay system provides a practical way to solve these problems, improving the performance of UAV communication in BLOS and cross-obstacle operations. In this study, a communication relay system, in which a quadrotor was used to relay radio communication for another quadrotor was developed and tested. First, the UAVs used as the airborne platform were constructed, and the hardware for the communication relay system was selected and built up. Second, a set of software programs and protocol for autonomous mission control, communication relay control, and ground control were developed. Finally, the system was fully integrated into the airborne platform and tested both indoor and in-flight. The Received Signal Strength Indication (RSSI) and noise value in two typical application scenarios were recorded. The test results demonstrated the ability of this system to extend the communication range and build communication over obstacles. This system also shows the feasibility to coordinate multiple UAVs' communication with the same relay structure.

Development and Testing of a Two-UAV Communication Relay System

PubMed Central

Li, Boyang; Jiang, Yifan; Sun, Jingxuan; Cai, Lingfeng; Wen, Chih-Yung

2016-01-01

In the development of beyond-line-of-sight (BLOS) Unmanned Aerial Vehicle (UAV) systems, communication between the UAVs and the ground control station (GCS) is of critical importance. The commonly used economical wireless modules are restricted by the short communication range and are easily blocked by obstacles. The use of a communication relay system provides a practical way to solve these problems, improving the performance of UAV communication in BLOS and cross-obstacle operations. In this study, a communication relay system, in which a quadrotor was used to relay radio communication for another quadrotor was developed and tested. First, the UAVs used as the airborne platform were constructed, and the hardware for the communication relay system was selected and built up. Second, a set of software programs and protocol for autonomous mission control, communication relay control, and ground control were developed. Finally, the system was fully integrated into the airborne platform and tested both indoor and in-flight. The Received Signal Strength Indication (RSSI) and noise value in two typical application scenarios were recorded. The test results demonstrated the ability of this system to extend the communication range and build communication over obstacles. This system also shows the feasibility to coordinate multiple UAVs’ communication with the same relay structure. PMID:27754369

Inverse models: A necessary next step in ground-water modeling

USGS Publications Warehouse

Poeter, E.P.; Hill, M.C.

1997-01-01

Inverse models using, for example, nonlinear least-squares regression, provide capabilities that help modelers take full advantage of the insight available from ground-water models. However, lack of information about the requirements and benefits of inverse models is an obstacle to their widespread use. This paper presents a simple ground-water flow problem to illustrate the requirements and benefits of the nonlinear least-squares repression method of inverse modeling and discusses how these attributes apply to field problems. The benefits of inverse modeling include: (1) expedited determination of best fit parameter values; (2) quantification of the (a) quality of calibration, (b) data shortcomings and needs, and (c) confidence limits on parameter estimates and predictions; and (3) identification of issues that are easily overlooked during nonautomated calibration.Inverse models using, for example, nonlinear least-squares regression, provide capabilities that help modelers take full advantage of the insight available from ground-water models. However, lack of information about the requirements and benefits of inverse models is an obstacle to their widespread use. This paper presents a simple ground-water flow problem to illustrate the requirements and benefits of the nonlinear least-squares regression method of inverse modeling and discusses how these attributes apply to field problems. The benefits of inverse modeling include: (1) expedited determination of best fit parameter values; (2) quantification of the (a) quality of calibration, (b) data shortcomings and needs, and (c) confidence limits on parameter estimates and predictions; and (3) identification of issues that are easily overlooked during nonautomated calibration.

Brief state-of-the-art review on optical communications for the NASA ISES workshop

NASA Technical Reports Server (NTRS)

Hendricks, Herbert D.

1990-01-01

The current state of the art of optical communications is briefly reviewed. This review covers NASA programs, DOD and other government agency programs, commercial aerospace programs, and foreign programs. Included is a brief summary of a recent NASA workshop on optical communications. The basic conclusions from all the program reviews is that optical communications is a technology ready to be accepted but needed to be demonstrated. Probably the most advanced and sophisticated optical communications system is the Laser Intersatellite Transmission Experiment (LITE) system developed for flight on the Advanced Communications Technology Satellite (ACTS). Optical communications technology is available for the applications of data communications at data rates in the under 300 MBits/sec for nearly all applications under 2 times GEO distances. Applications for low-earth orbiter (LEO) to ground will allow data rates in the multi-GBits/sec range. Higher data rates are limited by currently available laser power. Phased array lasers offer technology which should eliminate this problem. The major problem of cloud coverage can probably be eliminated by look ahead pointing, multiple ground stations, and knowledge of weather conditions to control the pointing. Most certainly, optical communications offer a new spectral region to relieve the RF bands and very high data communications rates that will be required in less than 10 years to solve the communications problems on Earth.

Onboard utilization of ground control points for image correction. Volume 3: Ground control point simulation software design

NASA Technical Reports Server (NTRS)

1981-01-01

The software developed to simulate the ground control point navigation system is described. The Ground Control Point Simulation Program (GCPSIM) is designed as an analysis tool to predict the performance of the navigation system. The system consists of two star trackers, a global positioning system receiver, a gyro package, and a landmark tracker.

Comparison of Airborne and Ground-Based Function Allocation Concepts for NextGen Using Human-In-The-Loop Simulations

NASA Technical Reports Server (NTRS)

Wing, David J.; Prevot, Thomas; Murdoch, Jennifer L.; Cabrall, Christopher D.; Homola, Jeffrey R.; Martin, Lynne H.; Mercer, Joey S.; Hoadley, Sherwood T.; Wilson, Sara R.; Hubbs, Clay E.;

Computational Studies of Strongly Correlated Quantum Matter

NASA Astrophysics Data System (ADS)

Shi, Hao

The study of strongly correlated quantum many-body systems is an outstanding challenge. Highly accurate results are needed for the understanding of practical and fundamental problems in condensed-matter physics, high energy physics, material science, quantum chemistry and so on. Our familiar mean-field or perturbative methods tend to be ineffective. Numerical simulations provide a promising approach for studying such systems. The fundamental difficulty of numerical simulation is that the dimension of the Hilbert space needed to describe interacting systems increases exponentially with the system size. Quantum Monte Carlo (QMC) methods are one of the best approaches to tackle the problem of enormous Hilbert space. They have been highly successful for boson systems and unfrustrated spin models. For systems with fermions, the exchange symmetry in general causes the infamous sign problem, making the statistical noise in the computed results grow exponentially with the system size. This hinders our understanding of interesting physics such as high-temperature superconductivity, metal-insulator phase transition. In this thesis, we present a variety of new developments in the auxiliary-field quantum Monte Carlo (AFQMC) methods, including the incorporation of symmetry in both the trial wave function and the projector, developing the constraint release method, using the force-bias to drastically improve the efficiency in Metropolis framework, identifying and solving the infinite variance problem, and sampling Hartree-Fock-Bogoliubov wave function. With these developments, some of the most challenging many-electron problems are now under control. We obtain an exact numerical solution of two-dimensional strongly interacting Fermi atomic gas, determine the ground state properties of the 2D Fermi gas with Rashba spin-orbit coupling, provide benchmark results for the ground state of the two-dimensional Hubbard model, and establish that the Hubbard model has a stripe order in the underdoped region.

Public Policy on Ground-Water Quality Protection. Proceedings of a National Conference (Virginia Polytechnic Inst. and State University, Blacksburg, Virginia, April 13-16, 1977).

ERIC Educational Resources Information Center

Kerns, Waldon R., Ed.

This publication contains the papers presented at a National Conference on Ground Water Quality Protection Policy held in April of 1977. Paper titles include: (1) Magnitude of the Ground-Water Contamination Problem; (2) Limited Degredation as a Ground-Water Quality Policy; (3) Surface and Subsurface Mining: Policy Implications; (4) Oil Well…

Ground-water quality in selected areas of Wisconsin

USGS Publications Warehouse

Hindall, S.M.

1979-01-01

Analysis of 2,071 ground-water samples from 970 wells throughout Wisconsin indicate large variations in ground-water quality. Ground water in Wisconsin is generally suitable for most uses, but in some areas concentrations of chemical constituents exceed recommended drinking-water standards. Iron, manganese, and nitrate commonly exceed recommended drinking-water standards and dissolved solids, sulfate, heavy metals, and phenolic materials may present local problems. (USGS)

Leibniz on the metaphysical foundation of physics

NASA Astrophysics Data System (ADS)

Temple, Daniel R.

This thesis examines how and why Leibniz felt that physics must be grounded in metaphysics. I argue that one of the strongest motivation Leibniz had for attempting to ground physics in metaphysics was his concern over the problem of induction. Even in his early writings, Leibniz was well aware of the problem of induction and how this problem threatened the very possibility of physics. Both his early and later theories of truth are geared towards solving this deep problem in the philosophy of science. In his early theory of truth, all truths are ultimately grounded in (but not necessarily reducible to) an identity. Hence, all truths are ultimately based in logic. Consequently, the problem of induction is seemingly solved since everything that happens, happens with the force of logical necessity. Unfortunately, this theory is incompatible with Leibniz's theory of possible worlds and hence, jeopardizes the liberty of God. In Leibniz's later theory of truth, Leibniz tries to overcome this weakness by acknowledging truths that are grounded in the free but moral necessity of God's actions. Since God's benevolence is responsible for the actualization of this world, then this world must possess rational laws. Furthermore, since God's rationality ensures that everything obeys the principle of sufficient reason, then we can use this principle to determine the fundamental laws of the universe. Leibniz himself attempts to derive these laws using this principle. Kant attempted to continue this work of securing the possibility of science, and the problems he encountered helped to shape his critical philosophy. So I conclude by a comparative analysis of Leibniz and Kant on the foundations of physics.

Apollo experience report: Guidance and control systems. Mission control programmer for unmanned missions AS-202, Apollo 4, and Apollo 6

NASA Technical Reports Server (NTRS)

Holloway, G. F.

1975-01-01

An unmanned test flight program required to evaluate the command module heat shield and the structural integrity of the command and service module/Saturn launch vehicle is described. The mission control programer was developed to provide the unmanned interface between the guidance and navigation computer and the other spacecraft systems for mission event sequencing and real-time ground control during missions AS-202, Apollo 4, and Apollo 6. The development of this unmanned programer is traced from the initial concept through the flight test phase. Detailed discussions of hardware development problems are given with the resulting solutions. The mission control programer functioned correctly without any flight anomalies for all missions. The Apollo 4 mission control programer was reused for the Apollo 6 flight, thus being one of the first subsystems to be reflown on an Apollo space flight.

Filtering method of star control points for geometric correction of remote sensing image based on RANSAC algorithm

NASA Astrophysics Data System (ADS)

Tan, Xiangli; Yang, Jungang; Deng, Xinpu

2018-04-01

In the process of geometric correction of remote sensing image, occasionally, a large number of redundant control points may result in low correction accuracy. In order to solve this problem, a control points filtering algorithm based on RANdom SAmple Consensus (RANSAC) was proposed. The basic idea of the RANSAC algorithm is that using the smallest data set possible to estimate the model parameters and then enlarge this set with consistent data points. In this paper, unlike traditional methods of geometric correction using Ground Control Points (GCPs), the simulation experiments are carried out to correct remote sensing images, which using visible stars as control points. In addition, the accuracy of geometric correction without Star Control Points (SCPs) optimization is also shown. The experimental results show that the SCPs's filtering method based on RANSAC algorithm has a great improvement on the accuracy of remote sensing image correction.

Tracked robot controllers for climbing obstacles autonomously

NASA Astrophysics Data System (ADS)

Vincent, Isabelle

2009-05-01

Research in mobile robot navigation has demonstrated some success in navigating flat indoor environments while avoiding obstacles. However, the challenge of analyzing complex environments to climb obstacles autonomously has had very little success due to the complexity of the task. Unmanned ground vehicles currently exhibit simple autonomous behaviours compared to the human ability to move in the world. This paper presents the control algorithms designed for a tracked mobile robot to autonomously climb obstacles by varying its tracks configuration. Two control algorithms are proposed to solve the autonomous locomotion problem for climbing obstacles. First, a reactive controller evaluates the appropriate geometric configuration based on terrain and vehicle geometric considerations. Then, a reinforcement learning algorithm finds alternative solutions when the reactive controller gets stuck while climbing an obstacle. The methodology combines reactivity to learning. The controllers have been demonstrated in box and stair climbing simulations. The experiments illustrate the effectiveness of the proposed approach for crossing obstacles.

The Systems Analysis of Problems of An Evaluation,prognosis and Optimization of Graund Water Management In Reclamated Areas

NASA Astrophysics Data System (ADS)

Vakhonin, N.

The problems connected to ground water dynamics take place in various areas of the people economic activity. For want of it in some branches the greatest interest rep- resents creation of quantitative parameters of a water mode, in one cases - of a level mode H(t) (land reclamation, agricultural and forest economy, ecology), in other - cre- ation of water discharge Q (t) (water-intakes for a water-supply or on the contrary - protective system from mines and quarry submerge). In a number of branches the ex- treme interest is represented by ground water quality dynamics (potable water-supply, inflow to rivers and lakes used for fish-breeding etc.). Each from these cases requires the account of features for want of creation of ground water dynamics models, re- alization of monitoring for their identification. With allowance for aid above in the report, the problems connected to ground water dynamics are bro-ken on three types: 1) evaluations of the system state and matching with normative parameters or match- ing of various objects among themselves; 2) prognosises of dynamics of ground water amount and quality; 3) problems of decision making support (optimization of ground water management), formalized as: The analysis is conducted for each of them and the conditions of choice of a generality level of a variable state describing ground stream dynamics (soil humidity, ground wa- ter level, water volume in the camera) and alternate variants, appropriate to them, of models describing water dynamics are shown: physical with the distributed parameters (equation of joint filtering of the bicomponent environment water-air, water-transfer equation, Boussinesk equation; with lumped parameters (chamber model with cam- eras of a various degree aggregating down to "a black box"), and also non-physical (statistical, regressive and neural networks) model. The possibility of using by each from these models for three selected types of problems is shown. On an example of reclamated agricultural object the correlation of ground water dynamics with other sub-systems is shown: by open channel streams, drains etc. also by processes: evapo- transpiration, infiltra-tion, snow melting etc. The possible versions of the processes in- teraction description with ground wa-ter dynamics are analyzed. The kinds of bound- ary conditions 1-st, 2-nd, 3-rd kind for internal and external boundaries of filtration stream are typed. There is formulated the request about necessity of monitoring real- 1 ization for the statistical task of source effects on more broad boundary of filtration stream, than optimized system. The model identification is carried out on the base of 24-year's monitoring data in the reclamated catchment of the river Yaselda. 2

A 2-lambda laser-induced flurorescence field instrument for ground-based and airborne measurements of atmospheric OH

NASA Technical Reports Server (NTRS)

Rodgers, M. O.; Bradshaw, J. D.; Sandholm, S. T.; Kesheng, S.; Davis, D. D.

1985-01-01

A number of techniques have been proposed for detecting atmospheric OH radicals. Of these, the laser-induced fluorescence (LIF) technique has been used by the largest number of investigators. One of the problems arising in connection with the implementation of this technique is related to the perturbing effect of the UV (lambda approximately 282 nm) laser beam used for OH monitoring, while another problem relates to signal extraction. Several new LIF approaches have been or are currently under development with the objective to bring both problems under control. The present paper deals with the experimental features of one of these new approaches. The considered approach is referred to as 2-lambda laser-induced fluorescence (2-lambda LIF). It is shown that the 2-lambda LIF system provides significant advantages over earlier 1-lambda LIF OH measurement instruments operating at ambient pressure.

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

Moore, Thomas W.; Quach, Tu-Thach; Detry, Richard Joseph

Complex Adaptive Systems of Systems, or CASoS, are vastly complex ecological, sociological, economic and/or technical systems which we must understand to design a secure future for the nation and the world. Perturbations/disruptions in CASoS have the potential for far-reaching effects due to pervasive interdependencies and attendant vulnerabilities to cascades in associated systems. Phoenix was initiated to address this high-impact problem space as engineers. Our overarching goals are maximizing security, maximizing health, and minimizing risk. We design interventions, or problem solutions, that influence CASoS to achieve specific aspirations. Through application to real-world problems, Phoenix is evolving the principles and discipline ofmore » CASoS Engineering while growing a community of practice and the CASoS engineers to populate it. Both grounded in reality and working to extend our understanding and control of that reality, Phoenix is at the same time a solution within a CASoS and a CASoS itself.« less

The Development and Implementation of Ground Safety Requirements for Project Orion Abort Flight Testing - A Case Study

NASA Technical Reports Server (NTRS)

Kirkpatrick, Paul D.; Williams, Jeffrey G.; Condzella, Bill R.

2008-01-01

A rigorous set of detailed ground safety requirements is required to make sure that ground support equipment (GSE) and associated planned ground operations are conducted safely. Detailed ground safety requirements supplement the GSE requirements already called out in NASA-STD-5005. This paper will describe the initial genesis of these ground safety requirements, the establishment and approval process and finally the implementation process for Project Orion. The future of the requirements will also be described. Problems and issues encountered and overcame will be discussed.

Witnessing eigenstates for quantum simulation of Hamiltonian spectra

PubMed Central

Santagati, Raffaele; Wang, Jianwei; Gentile, Antonio A.; Paesani, Stefano; Wiebe, Nathan; McClean, Jarrod R.; Morley-Short, Sam; Shadbolt, Peter J.; Bonneau, Damien; Silverstone, Joshua W.; Tew, David P.; Zhou, Xiaoqi; O’Brien, Jeremy L.; Thompson, Mark G.

2018-01-01

The efficient calculation of Hamiltonian spectra, a problem often intractable on classical machines, can find application in many fields, from physics to chemistry. We introduce the concept of an “eigenstate witness” and, through it, provide a new quantum approach that combines variational methods and phase estimation to approximate eigenvalues for both ground and excited states. This protocol is experimentally verified on a programmable silicon quantum photonic chip, a mass-manufacturable platform, which embeds entangled state generation, arbitrary controlled unitary operations, and projective measurements. Both ground and excited states are experimentally found with fidelities >99%, and their eigenvalues are estimated with 32 bits of precision. We also investigate and discuss the scalability of the approach and study its performance through numerical simulations of more complex Hamiltonians. This result shows promising progress toward quantum chemistry on quantum computers. PMID:29387796

An Induced Environment Contamination Monitor for the Space Shuttle

NASA Technical Reports Server (NTRS)

Miller, E. R. (Editor); Decher, R. (Editor)

1978-01-01

The Induced Environment Contamination Monitor (IECM), a set of ten instruments integrated into a self-contained unit and scheduled to fly on shuttle Orbital Flight Tests 1 through 6 and on Spacelabs 1 and 2, is described. The IECM is designed to measure the actual environment to determine whether the strict controls placed on the shuttle system have solved the contamination problem. Measurements are taken during prelaunch, ascent, on-orbit, descent, and postlanding. The on-orbit measurements are molecular return flux, background spectral intensity, molecular deposition, and optical surface effects. During the other mission phases dew point, humidity, aerosol content, and trace gas are measured as well as optical surface effects and molecular deposition. The IECM systems and thermal design are discussed. Preflight and ground operations are presented together with associated ground support equipment. Flight operations and data reduction plans are given.

Research perspectives in the field of ground penetrating radars in Armenia

NASA Astrophysics Data System (ADS)

Baghdasaryan, Hovik; Knyazyan, Tamara; Hovhannisyan, Tamara

2014-05-01

Armenia is a country located in a very complicated region from geophysical point of view. It is situated on a cross of several tectonic plates and a lot of dormant volcanoes. The main danger is earthquakes and the last big disaster was in 1988 in the northwest part of contemporary Armenia. As a consequence, the main direction of geophysical research is directed towards monitoring and data analysis of seismic activity. National Academy of Sciences of Armenia is conducting these activities in the Institute of Geological Sciences and in the Institute of Geophysics and Engineering Seismology. Research in the field of ground penetrating radars is considered in Armenia as an advanced and perspective complement to the already exploiting research tools. The previous achievements of Armenia in the fields of radiophysics, antenna measurements, laser physics and existing relevant research would permit to initiate new promising area of research in the direction of theory and experiments of ground penetrating radars. One of the key problems in the operation of ground penetrating radars is correct analysis of peculiarities of electromagnetic wave interaction with different layers of the earth. For this, the well-known methods of electromagnetic boundary problem solutions are applied. In addition to the existing methods our research group of Fiber Optics Communication Laboratory at the State Engineering University of Armenia declares its interest in exploring the possibilities of new non-traditional method of boundary problems solution for electromagnetic wave interaction with the ground. This new method for solving boundary problems of electrodynamics is called the method of single expression (MSE) [1-3]. The distinctive feature of this method is denial from the presentation of wave equation's solution in the form of counter-propagating waves, i.e. denial from the superposition principal application. This permits to solve linear and nonlinear (field intensity-dependent) problems with the same exactness, without any approximations. It is favourable also since in solution of boundary problems in the MSE there is no necessity in applying absorbing boundary conditions at the model edges by terminating the computational domain. In the MSE the computational process starts from the rear side of any multilayer structure that ensures the uniqueness of problem solution without application of any artificial absorbing boundary conditions. Previous success of the MSE application in optical domain gives us confidence in successful extension of this method's use for solution of different problems related to electromagnetic wave interaction with the layers of the earth and buried objects in the ground. This work benefited from networking activities carried out within the EU funded COST Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar." 1. H.V. Baghdasaryan, T.M. Knyazyan, 'Problem of Plane EM Wave Self-action in Multilayer Structure: an Exact Solution', Optical and Quantum Electronics, vol. 31, 1999, pp.1059-1072. 2. H.V. Baghdasaryan, T.M. Knyazyan, 'Modelling of strongly nonlinear sinusoidal Bragg gratings by the Method of Single Expression', Optical and Quantum Electronics, vol. 32, 2000, pp. 869-883. 3. H.V. Baghdasaryan, 'Basics of the Method of Single Expression: New Approach for Solving Boundary Problems in Classical Electrodynamics', Yerevan, Chartaraget, 2013.

Mechanization of and experience with a triplex fly-by-wire backup control system

NASA Technical Reports Server (NTRS)

Lock, W. P.; Petersen, W. R.; Whitman, G. B.

1975-01-01

A redundant three-axis analog control system was designed and developed to back up a digital fly-by-wire control system for an F-8C airplane. Forty-two flights, involving 58 hours of flight time, were flown by six pilots. The mechanization and operational experience with the backup control system, the problems involved in synchronizing it with the primary system, and the reliability of the system are discussed. The backup control system was dissimilar to the primary system, and it provided satisfactory handling through the flight envelope evaluated. Limited flight tests of a variety of control tasks showed that control was also satisfactory when the backup control system was controlled by a minimum-displacement (force) side stick. The operational reliability of the F-8 digital fly-by-wire control system was satisfactory, with no unintentional downmodes to the backup control system in flight. The ground and flight reliability of the system's components is discussed.

The growth of railway ground vibration problems - A review.

PubMed

Connolly, David P; Marecki, Grzegorz P; Kouroussis, Georges; Thalassinakis, Ioannis; Woodward, Peter K

2016-10-15

Ground-borne noise and vibration from railway lines can cause human distress/annoyance, and also negatively affect real estate property values. Therefore this paper analyses a collection of technical ground-borne noise and vibration reports, detailing commercial vibration assessments undertaken at 1604 railway track sections, in 9 countries across the world. A wide range of rail projects are considered including light rail, tram lines, underground/tunnelled lines, freight, conventional rail and high speed rail. It documents the rise in ground-borne vibration problems and trends in the prediction industry, with the aim of informing the current research area. Firstly, the reports are analysed chronologically and it is found that railway vibration is a growing global concern, and as such, assessments have become more prevalent. International assessment metrics are benchmarked and it is found that velocity decibels (VdB), vibration dose value (VDV) and peak particle velocity (PPV) are the most commonly used methods of assessment. Furthermore, to predict vibration levels, the physical measurement of frequency transfer functions is preferential to numerical modelling. Results from the reports show that ground vibration limits are exceeded in 44% of assessments, and that ground-borne noise limits are exceeded in 31%. Moreover, mitigation measures were required on approximately 50% of projects, revealing that ground-borne noise and vibration is a widespread railroad engineering challenge. To solve these problems, the most commonly used abatement strategy is a modification of the railtrack structure (active mitigation), rather than the implementation of a more passive solution in the far-field. Copyright © 2015 Elsevier B.V. All rights reserved.

A celestial assisted INS initialization method for lunar explorers.

PubMed

Ning, Xiaolin; Wang, Longhua; Wu, Weiren; Fang, Jiancheng

2011-01-01

The second and third phases of the Chinese Lunar Exploration Program (CLEP) are planning to achieve Moon landing, surface exploration and automated sample return. In these missions, the inertial navigation system (INS) and celestial navigation system (CNS) are two indispensable autonomous navigation systems which can compensate for limitations in the ground based navigation system. The accurate initialization of the INS and the precise calibration of the CNS are needed in order to achieve high navigation accuracy. Neither the INS nor the CNS can solve the above problems using the ground controllers or by themselves on the lunar surface. However, since they are complementary to each other, these problems can be solved by combining them together. A new celestial assisted INS initialization method is presented, in which the initial position and attitude of the explorer as well as the inertial sensors' biases are estimated by aiding the INS with celestial measurements. Furthermore, the systematic error of the CNS is also corrected by the help of INS measurements. Simulations show that the maximum error in position is 300 m and in attitude 40″, which demonstrates this method is a promising and attractive scheme for explorers on the lunar surface.

A Celestial Assisted INS Initialization Method for Lunar Explorers

PubMed Central

Ning, Xiaolin; Wang, Longhua; Wu, Weiren; Fang, Jiancheng

2011-01-01

The second and third phases of the Chinese Lunar Exploration Program (CLEP) are planning to achieve Moon landing, surface exploration and automated sample return. In these missions, the inertial navigation system (INS) and celestial navigation system (CNS) are two indispensable autonomous navigation systems which can compensate for limitations in the ground based navigation system. The accurate initialization of the INS and the precise calibration of the CNS are needed in order to achieve high navigation accuracy. Neither the INS nor the CNS can solve the above problems using the ground controllers or by themselves on the lunar surface. However, since they are complementary to each other, these problems can be solved by combining them together. A new celestial assisted INS initialization method is presented, in which the initial position and attitude of the explorer as well as the inertial sensors’ biases are estimated by aiding the INS with celestial measurements. Furthermore, the systematic error of the CNS is also corrected by the help of INS measurements. Simulations show that the maximum error in position is 300 m and in attitude 40″, which demonstrates this method is a promising and attractive scheme for explorers on the lunar surface. PMID:22163998

A new pre-loaded beam geometric stiffness matrix with full rigid body capabilities

NASA Astrophysics Data System (ADS)

Bosela, P. A.; Fertis, D. G.; Shaker, F. J.

1992-09-01

Space structures, such as the Space Station solar arrays, must be extremely light-weight, flexible structures. Accurate prediction of the natural frequencies and mode shapes is essential for determining the structural adequacy of components, and designing a controls system. The tension pre-load in the 'blanket' of photovoltaic solar collectors, and the free/free boundary conditions of a structure in space, causes serious reservations on the use of standard finite element techniques of solution. In particular, a phenomenon known as 'grounding', or false stiffening, of the stiffness matrix occurs during rigid body rotation. The authors have previously shown that the grounding phenomenon is caused by a lack of rigid body rotational capability, and is typical in beam geometric stiffness matrices formulated by others, including those which contain higher order effects. The cause of the problem was identified as the force imbalance inherent in the formulations. In this paper, the authors develop a beam geometric stiffness matrix for a directed force problem, and show that the resultant global stiffness matrix contains complete rigid body mode capabilities, and performs very well in the diagonalization methodology customarily used in dynamic analysis.

Public health oncology: a framework for progress in low- and middle-income countries.

PubMed

Love, R R; Ginsburg, O M; Coleman, C N

2012-12-01

The problems of cancer are increasing in low- and middle-income countries (LMCs), which now have significant majorities of the global case and mortality burdens. The professional oncology community is being increasingly called upon to define pragmatic and realistic approaches to these problems. Focusing on mortality and case burden outcomes defines public health oncology or population-affecting cancer medicine. We use this focus to consider practical approaches. The greatest cancer burdens are in Asia. A public health oncology perspective mandates: first, addressing the major and social challenges of cancer medicine for populations: human rights, health systems, corruption, and our limited knowledge base for value-conscious interventions. Second, adoption of evolving concepts and models for sustainable development in LMCs. Third, clear and realistic statements of action and inaction affecting populations, grounded in our best cancer science, and attention to these. Finally, framing the goals and challenges for population-affecting cancer medicine requires a change in paradigm from historical top-down models of technology transfer, to one which is community-grounded and local-evidence based. Public health oncology perspectives define clear focus for much needed research on country-specific practical approaches to cancer control.

Public health oncology: a framework for progress in low- and middle-income countries†

PubMed Central

Love, R. R.; Ginsburg, O. M.; Coleman, C. N.

2012-01-01

Background The problems of cancer are increasing in low- and middle-income countries (LMCs), which now have significant majorities of the global case and mortality burdens. The professional oncology community is being increasingly called upon to define pragmatic and realistic approaches to these problems. Patients and methods Focusing on mortality and case burden outcomes defines public health oncology or population-affecting cancer medicine. We use this focus to consider practical approaches. Results The greatest cancer burdens are in Asia. A public health oncology perspective mandates: first, addressing the major and social challenges of cancer medicine for populations: human rights, health systems, corruption, and our limited knowledge base for value-conscious interventions. Second, adoption of evolving concepts and models for sustainable development in LMCs. Third, clear and realistic statements of action and inaction affecting populations, grounded in our best cancer science, and attention to these. Finally, framing the goals and challenges for population-affecting cancer medicine requires a change in paradigm from historical top-down models of technology transfer, to one which is community-grounded and local-evidence based. Conclusion Public health oncology perspectives define clear focus for much needed research on country-specific practical approaches to cancer control. PMID:23087162

Integrated optimization of unmanned aerial vehicle task allocation and path planning under steady wind.

PubMed

Luo, He; Liang, Zhengzheng; Zhu, Moning; Hu, Xiaoxuan; Wang, Guoqiang

2018-01-01

Wind has a significant effect on the control of fixed-wing unmanned aerial vehicles (UAVs), resulting in changes in their ground speed and direction, which has an important influence on the results of integrated optimization of UAV task allocation and path planning. The objective of this integrated optimization problem changes from minimizing flight distance to minimizing flight time. In this study, the Euclidean distance between any two targets is expanded to the Dubins path length, considering the minimum turning radius of fixed-wing UAVs. According to the vector relationship between wind speed, UAV airspeed, and UAV ground speed, a method is proposed to calculate the flight time of UAV between targets. On this basis, a variable-speed Dubins path vehicle routing problem (VS-DP-VRP) model is established with the purpose of minimizing the time required for UAVs to visit all the targets and return to the starting point. By designing a crossover operator and mutation operator, the genetic algorithm is used to solve the model, the results of which show that an effective UAV task allocation and path planning solution under steady wind can be provided.

Integrated optimization of unmanned aerial vehicle task allocation and path planning under steady wind

PubMed Central

Liang, Zhengzheng; Zhu, Moning; Hu, Xiaoxuan; Wang, Guoqiang

2018-01-01

Wind has a significant effect on the control of fixed-wing unmanned aerial vehicles (UAVs), resulting in changes in their ground speed and direction, which has an important influence on the results of integrated optimization of UAV task allocation and path planning. The objective of this integrated optimization problem changes from minimizing flight distance to minimizing flight time. In this study, the Euclidean distance between any two targets is expanded to the Dubins path length, considering the minimum turning radius of fixed-wing UAVs. According to the vector relationship between wind speed, UAV airspeed, and UAV ground speed, a method is proposed to calculate the flight time of UAV between targets. On this basis, a variable-speed Dubins path vehicle routing problem (VS-DP-VRP) model is established with the purpose of minimizing the time required for UAVs to visit all the targets and return to the starting point. By designing a crossover operator and mutation operator, the genetic algorithm is used to solve the model, the results of which show that an effective UAV task allocation and path planning solution under steady wind can be provided. PMID:29561888

Upsets related to spacecraft charging

NASA Astrophysics Data System (ADS)

Frederickson, A. R.

1996-04-01

The charging of spacecraft components by high energy radiation can result in spontaneous pulsed discharges. The pulses can interrupt normal operations of spacecraft electronics. The 20-year history of ground studies and spacecraft studies of this phenomenon are reviewed. The data from space are not sufficient to unambiguously point to a few specific solutions. The ground based data continue to find more problem areas the longer one looks. As spacecraft become more complex and carry less radiation shielding, the charging and discharging of insulators is becoming a more critical problem area. Ground experiments indicate that solutions for spacecraft are multiple and diverse, and many technical details are reviewed or introduced here.

Use of Picard and Newton iteration for solving nonlinear ground water flow equations

USGS Publications Warehouse

Mehl, S.

2006-01-01

This study examines the use of Picard and Newton iteration to solve the nonlinear, saturated ground water flow equation. Here, a simple three-node problem is used to demonstrate the convergence difficulties that can arise when solving the nonlinear, saturated ground water flow equation in both homogeneous and heterogeneous systems with and without nonlinear boundary conditions. For these cases, the characteristic types of convergence patterns are examined. Viewing these convergence patterns as orbits of an attractor in a dynamical system provides further insight. It is shown that the nonlinearity that arises from nonlinear head-dependent boundary conditions can cause more convergence difficulties than the nonlinearity that arises from flow in an unconfined aquifer. Furthermore, the effects of damping on both convergence and convergence rate are investigated. It is shown that no single strategy is effective for all problems and how understanding pitfalls and merits of several methods can be helpful in overcoming convergence difficulties. Results show that Picard iterations can be a simple and effective method for the solution of nonlinear, saturated ground water flow problems.

The thermo-vibrational convection in microgravity condition. Ground-based modelling.

NASA Astrophysics Data System (ADS)

Zyuzgin, A. V.; Putin, G. F.; Harisov, A. F.

In 1995-2000 at orbital station "Mir" has been carried out the series of experiments with the equipment "Alice" for the studying regimes of heat transfer in the supercritical fluids under influence inertial microaccelerations. The experiments have found out existence of the thermo-vibrational and thermo-inertial convective movements in the real weightlessness[1] and controlling microgravity fields[2]. However regarding structures of thermovibrational convection the results of experiments have inconsistent character. Therefore carrying out the ground-based modeling of the given problem is actually. In this work in laboratory conditions were investigated the thermo-vibrational convective movements from the dot heat source at high-frequency vibrations of the cavity with the fluid and presence quasi-static microacceleration. As the result of ground-based modeling, the regimes of convective flows, similar observed in the space experiment are received. Evolution of the convective structures and the spatial-temporary characteristics of movements are investigated in a wide range of the problem parameters. The control criteria and its critical value are determined. The received results well coordinated to the data of space experiments and allow adding and expanding representation about thermo-vibrational effects in conditions of real weightlessness and remove the contradictions concerning structures thermo-vibrational convective flows, received at the analysis of the given orbital experiments. The research described in this publication was made possible in part by Russian Foundation for Basic Research and Administration of Perm Region, Russia, under grant 04-02-96038, and Award No. PE-009-0 of the U.S. Civilian Research & Development Foundation for the Independent States of the Former Soviet Union (CRDF). A.V. Zyuzgin, A. I. Ivanov, V. I. Polezhaev, G. F. Putin, E. B. Soboleva Convective Motions in Near-Critical Fluids under Real Zero-Gravity Conditions. Cosmic Research, Vol. 39, No. 2, 2001, pp. 175--186. A.V. Zyuzgin, G.F. Putin, N.G. Ivanova, A.V. Chudinov, A.I. Ivanov, A.V. Kalmykov, V. I. Polezhaev, V.M. Emelianov The heat convection of nearcritical fluid in the controlled microacceleration field under zero-gravity condition. Advances in Space Research, 2003, Vol. 32, No 2, pp. 205-210.

Quantum Adiabatic Algorithms and Large Spin Tunnelling

NASA Technical Reports Server (NTRS)

Boulatov, A.; Smelyanskiy, V. N.

2003-01-01

We provide a theoretical study of the quantum adiabatic evolution algorithm with different evolution paths proposed in this paper. The algorithm is applied to a random binary optimization problem (a version of the 3-Satisfiability problem) where the n-bit cost function is symmetric with respect to the permutation of individual bits. The evolution paths are produced, using the generic control Hamiltonians H (r) that preserve the bit symmetry of the underlying optimization problem. In the case where the ground state of H(0) coincides with the totally-symmetric state of an n-qubit system the algorithm dynamics is completely described in terms of the motion of a spin-n/2. We show that different control Hamiltonians can be parameterized by a set of independent parameters that are expansion coefficients of H (r) in a certain universal set of operators. Only one of these operators can be responsible for avoiding the tunnelling in the spin-n/2 system during the quantum adiabatic algorithm. We show that it is possible to select a coefficient for this operator that guarantees a polynomial complexity of the algorithm for all problem instances. We show that a successful evolution path of the algorithm always corresponds to the trajectory of a classical spin-n/2 and provide a complete characterization of such paths.

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

USGS Publications Warehouse

Bloyd, Richard M.

1974-01-01

Rapid advance of techniques in ground-water hydrology during recent years has provided methods which the hydrologist can use for evaluating planned ground-water development. Therefore, the manager can resolve the inherent problems that historically have bred caution when this part of our total water resource was considered for development.

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.

Scaled Composites' Doug Shane examines the screen of his ground control station during tests in New Mexico. Shane used this configuration as the ground control station to remotely pilot the Proteus aircraft during a NASA sponsored series of tests.

NASA Image and Video Library

2002-03-13

Scaled Composites' Doug Shane examines the screen of his ground control station during tests in New Mexico. Shane used this configuration as the ground control station to remotely pilot the Proteus aircraft during a NASA sponsored series of tests.

Undecidability of the spectral gap.

PubMed

Cubitt, Toby S; Perez-Garcia, David; Wolf, Michael M

2015-12-10

The spectral gap--the energy difference between the ground state and first excited state of a system--is central to quantum many-body physics. Many challenging open problems, such as the Haldane conjecture, the question of the existence of gapped topological spin liquid phases, and the Yang-Mills gap conjecture, concern spectral gaps. These and other problems are particular cases of the general spectral gap problem: given the Hamiltonian of a quantum many-body system, is it gapped or gapless? Here we prove that this is an undecidable problem. Specifically, we construct families of quantum spin systems on a two-dimensional lattice with translationally invariant, nearest-neighbour interactions, for which the spectral gap problem is undecidable. This result extends to undecidability of other low-energy properties, such as the existence of algebraically decaying ground-state correlations. The proof combines Hamiltonian complexity techniques with aperiodic tilings, to construct a Hamiltonian whose ground state encodes the evolution of a quantum phase-estimation algorithm followed by a universal Turing machine. The spectral gap depends on the outcome of the corresponding 'halting problem'. Our result implies that there exists no algorithm to determine whether an arbitrary model is gapped or gapless, and that there exist models for which the presence or absence of a spectral gap is independent of the axioms of mathematics.

Electromagnetic imaging with an arbitrarily oriented magnetic dipole

NASA Astrophysics Data System (ADS)

Guillemoteau, Julien; Sailhac, Pascal; Behaegel, Mickael

2013-04-01

We present the theoretical background for the geophysical EM analysis with arbitrarily oriented magnetic dipoles. The first application of such a development is that we would now be able to correct the data when they are not acquired in accordance to the actual interpretation methods. In order to illustrate this case, we study the case of airborne TEM measurements over an inclined ground. This context can be encountered if the measurements are made in mountain area. We show in particular that transient central loop helicopter borne magnetic data should be corrected by a factor proportional to the angle of the slope under the system. In addition, we studied the sensitivity function of a grounded multi-angle frequency domain system. Our development leads to a general Jacobian kernel that could be used for all the induction number and all the position/orientation of both transmitter and receiver in the air layer. Indeed, if one could design a system controlling the angles of Tx and Rx, the present development would allow to interpret such a data set and enhance the ground analysis, especially in order to constrain the 3D anisotropic inverse problem.

9 CFR 416.2 - Establishment grounds and facilities.

Code of Federal Regulations, 2014 CFR

2014-01-01

... ACT SANITATION § 416.2 Establishment grounds and facilities. (a) Grounds and pest control. The grounds... place a pest management program to prevent the harborage and breeding of pests on the grounds and within establishment facilities. Pest control substances used must be safe and effective under the conditions of use...

9 CFR 416.2 - Establishment grounds and facilities.

Code of Federal Regulations, 2013 CFR

2013-01-01

... ACT SANITATION § 416.2 Establishment grounds and facilities. (a) Grounds and pest control. The grounds... place a pest management program to prevent the harborage and breeding of pests on the grounds and within establishment facilities. Pest control substances used must be safe and effective under the conditions of use...

9 CFR 416.2 - Establishment grounds and facilities.

Code of Federal Regulations, 2012 CFR

2012-01-01

... ACT SANITATION § 416.2 Establishment grounds and facilities. (a) Grounds and pest control. The grounds... place a pest management program to prevent the harborage and breeding of pests on the grounds and within establishment facilities. Pest control substances used must be safe and effective under the conditions of use...

Summary of hydrologic conditions of the Louisville area of Kentucky

USGS Publications Warehouse

Bell, Edwin Allen

1966-01-01

Water problems and their solutions have been associated with the growth and development of the Louisville area for more than a century. Many hydrologic data that aided water users in the past can be applied to present water problems and will be helpful for solving many similar problems in the future. Most of the water problems of Louisville, a water-rich area, concern management and are associated with the distribution of supplies, the quality of water, drainage, and waste disposal. The local hydrologic system at Louisville is dominated by the Ohio River and the glacial-outwash deposits beneath its flood plain. The water-bearing limestones in the uplands are ,secondary sources of water. The average flow of the Ohio River at Louisville, 73 billion gallons per day, and the potential availability of 370 million gallons per day of ground water suitable for industrial cooling purposes minimize the chance of acute water shortage in the area. Under current development, use of water averages about 211 million gallons per day, excluding about 392 million gallons of Ohio River water circulated daily through steampower plants and returned directly to the river. Optimum use and control of the water resources will be dependent on solving several water problems. The principal sources of water are in the Ohio River bottom land, whereas the new and potential centers of use are in the uplands. Either water must be piped to these new centers from the present sources or new supplies must be developed. Available data on streamflow and ground water are adequate to plan for the development of small local supplies. Since the completion of floodwalls and levees in 1953, widespread damage from flooding is a thing of the past in the Louisville area. Some local flooding of unprotected areas and of lowlands along tributary streams still takes place. The analyses of streamflow data are useful in planning for protection of these areas, but additional streamflow records and flood-area mapping are needed to best solve the problem. Droughts are a problem only to users of small water supplies in the uplands, where additional water either can be imported or developed locally. Pollution and undesirable chemical quality of water for some uses are the most serious drawbacks to the optimum development of the water resources in Louisville and Jefferson County. Available chemical analyses of ground water are useful for determining its suitability for various uses, but additional data are needed to guide management decisions. Sources of contamination should be inventoried and water samples analyzed periodically to monitor changes in quality.

The structures and the role of an international agency for the control of satellites

NASA Technical Reports Server (NTRS)

Dupuy, R. J.

1984-01-01

Legal questions involved in the liability of a proposed agency which would control internationally owned satellites for monitoring worldwide compliance with arms control agreements are discussed. Difficulties in acquiring the signed consent of all the relevant nations, and guaranteeing satisfactory compliance with the terms of such an agreement are noted. Additional problems to be solved comprise the construction of the ground based facilities and the satellites, the funding for the venture, and the reconciliation of the functions of the proposed agency with the sovereignty of individual states. The agency would gather, treat, and format data for signatories of arms control agreements and provide technical assistance in crisis conditions. It is concluded that the existence and functioning of the agency would reduce the amount of classified information and would consequently reduce the level of international tensions.

State and local response to damaging land subsidence in United States urban areas

USGS Publications Warehouse

Holzer, T.L.

1989-01-01

Land subsidence caused by man-induced depressuring of underground reservoirs has occurred in at least nine urban areas in the United States. Significant efforts to control it have been made in three areas: Long Beach, California; Houston-Galveston, Texas; and Santa Clara Valley, California. In these areas coastal flooding and its control cost more than $300 million. Institutional changes were required in each area to ameliorate its subsidence problem. In Long Beach and Houston Galveston, efforts were made to mitigate subsidence only after significant flood damage had occurred. To arrest subsidence at Long Beach, the city lobbied for a special state law, the California Subsidence Act, that required unitization and repressuring of the Wilmington oil field. In the Houston-Galveston region, the Texas State Legislature authorized formation of the Harris-Galveston Coastal Subsidence District with authority to regulate groundwater pumping by permit. This solution, which was achieved through efforts of entities affected by subsidence, was the product of a series of compromises necessitated by political fragmentation and disjointed water planning in the region. Amelioration of subsidence in the Santa Clara Valley was a collateral benefit from the effort by water users to curtail ground-water overdraft in the valley. Importation of surface water and a tax on ground-water pumpage reduced ground-water use, thereby allowing the recovery of water level and the arresting of subsidence.

Aerodynamic Drag Analysis of 3-DOF Flex-Gimbal GyroWheel System in the Sense of Ground Test

PubMed Central

Huo, Xin; Feng, Sizhao; Liu, Kangzhi; Wang, Libin; Chen, Weishan

2016-01-01

GyroWheel is an innovative device that combines the actuating capabilities of a control moment gyro with the rate sensing capabilities of a tuned rotor gyro by using a spinning flex-gimbal system. However, in the process of the ground test, the existence of aerodynamic disturbance is inevitable, which hinders the improvement of the specification performance and control accuracy. A vacuum tank test is a possible candidate but is sometimes unrealistic due to the substantial increase in costs and complexity involved. In this paper, the aerodynamic drag problem with respect to the 3-DOF flex-gimbal GyroWheel system is investigated by simulation analysis and experimental verification. Concretely, the angular momentum envelope property of the spinning rotor system is studied and its integral dynamical model is deduced based on the physical configuration of the GyroWheel system with an appropriately defined coordinate system. In the sequel, the fluid numerical model is established and the model geometries are checked with FLUENT software. According to the diversity and time-varying properties of the rotor motions in three-dimensions, the airflow field around the GyroWheel rotor is analyzed by simulation with respect to its varying angular velocity and tilt angle. The IPC-based experimental platform is introduced, and the properties of aerodynamic drag in the ground test condition are obtained through comparing the simulation with experimental results. PMID:27941602

AMO EXPRESS: A Command and Control Experiment for Crew Autonomy Onboard the International Space Station

NASA Technical Reports Server (NTRS)

Stetson, Howard K.; Frank, Jeremy; Cornelius, Randy; Haddock, Angie; Wang, Lui; Garner, Larry

2015-01-01

NASA is investigating a range of future human spaceflight missions, including both Mars-distance and Near Earth Object (NEO) targets. Of significant importance for these missions is the balance between crew autonomy and vehicle automation. As distance from Earth results in increasing communication delays, future crews need both the capability and authority to independently make decisions. However, small crews cannot take on all functions performed by ground today, and so vehicles must be more automated to reduce the crew workload for such missions. NASA's Advanced Exploration Systems Program funded Autonomous Mission Operations (AMO) project conducted an autonomous command and control experiment on-board the International Space Station that demonstrated single action intelligent procedures for crew command and control. The target problem was to enable crew initialization of a facility class rack with power and thermal interfaces, and involving core and payload command and telemetry processing, without support from ground controllers. This autonomous operations capability is enabling in scenarios such as initialization of a medical facility to respond to a crew medical emergency, and representative of other spacecraft autonomy challenges. The experiment was conducted using the Expedite the Processing of Experiments for Space Station (EXPRESS) rack 7, which was located in the Port 2 location within the U.S Laboratory onboard the International Space Station (ISS). Activation and deactivation of this facility is time consuming and operationally intensive, requiring coordination of three flight control positions, 47 nominal steps, 57 commands, 276 telemetry checks, and coordination of multiple ISS systems (both core and payload). Utilization of Draper Laboratory's Timeliner software, deployed on-board the ISS within the Command and Control (C&C) computers and the Payload computers, allowed development of the automated procedures specific to ISS without having to certify and employ novel software for procedure development and execution. The procedures contained the ground procedure logic and actions as possible to include fault detection and recovery capabilities.

Coherent population trapping with a controlled dissipation: applications in optical metrology

NASA Astrophysics Data System (ADS)

Nicolas, L.; Delord, T.; Jamonneau, P.; Coto, R.; Maze, J.; Jacques, V.; Hétet, G.

2018-03-01

We analyze the properties of a pulsed coherent population trapping protocol that uses a controlled decay from the excited state in a Λ-level scheme. We study this problem analytically and numerically and find regimes where narrow transmission, absorption, or fluorescence spectral lines occur. We then look for optimal frequency measurements using these spectral features by computing the Allan deviation in the presence of ground state decoherence and show that the protocol is on a par with Ramsey-CPT. We discuss possible implementations with ensembles of alkali atoms and single ions and demonstrate that typical pulsed-CPT experiments that are realized on femto-second timescales can be implemented on micro-seconds timescales using this scheme.

ATS-1/ATS-3 dual satellite navigation study

NASA Technical Reports Server (NTRS)

Hoover, W. M.

1971-01-01

A study which illustrated the feasibility of implementing an on-board aircraft navigation system based on using the ATS-1 and ATS-3 satellites, the modified Omega Position Location Equipment (OPLE) Control Center, and a suitable aircraft terminal was conducted. The report provides: (1) a consideration of the problems of satellite navigation and an objective definition of the optimum system under the constraints of its specified components, (2) a description of the necessary modifications to the OPLE Control Center, the design of an aircraft terminal, and the design of ground reference terminals, and (3) an outline of an experiment plan and an estimate of the cost to be expected in conducting the program.

Bibliography on Ground Vehicle Communications & Control : A KWIC Index

DOT National Transportation Integrated Search

1971-08-01

This bibliography, or the subject of communication and control of ground vehicles, covers the fields of land-mobile communication, computer-aided traffic control, communication with high speed ground vehicles and radio frequency noise. Emphasis is pl...

An optimization-based integrated controls-structures design methodology for flexible space structures

NASA Technical Reports Server (NTRS)

Maghami, Peiman G.; Joshi, Suresh M.; Armstrong, Ernest S.

1993-01-01

An approach for an optimization-based integrated controls-structures design is presented for a class of flexible spacecraft that require fine attitude pointing and vibration suppression. The integrated design problem is posed in the form of simultaneous optimization of both structural and control design variables. The approach is demonstrated by application to the integrated design of a generic space platform and to a model of a ground-based flexible structure. The numerical results obtained indicate that the integrated design approach can yield spacecraft designs that have substantially superior performance over a conventional design wherein the structural and control designs are performed sequentially. For example, a 40-percent reduction in the pointing error is observed along with a slight reduction in mass, or an almost twofold increase in the controlled performance is indicated with more than a 5-percent reduction in the overall mass of the spacecraft (a reduction of hundreds of kilograms).

Experimental study of adaptive pointing and tracking for large flexible space structures

NASA Technical Reports Server (NTRS)

Boussalis, D.; Bayard, D. S.; Ih, C.; Wang, S. J.; Ahmed, A.

1991-01-01

This paper describes an experimental study of adaptive pointing and tracking control for flexible spacecraft conducted on a complex ground experiment facility. The algorithm used in this study is based on a multivariable direct model reference adaptive control law. Several experimental validation studies were performed earlier using this algorithm for vibration damping and robust regulation, with excellent results. The current work extends previous studies by addressing the pointing and tracking problem. As is consistent with an adaptive control framework, the plant is assumed to be poorly known to the extent that only system level knowledge of its dynamics is available. Explicit bounds on the steady-state pointing error are derived as functions of the adaptive controller design parameters. It is shown that good tracking performance can be achieved in an experimental setting by adjusting adaptive controller design weightings according to the guidelines indicated by the analytical expressions for the error.

Multi-Agent Cooperative Target Search

PubMed Central

Hu, Jinwen; Xie, Lihua; Xu, Jun; Xu, Zhao

2014-01-01

This paper addresses a vision-based cooperative search for multiple mobile ground targets by a group of unmanned aerial vehicles (UAVs) with limited sensing and communication capabilities. The airborne camera on each UAV has a limited field of view and its target discriminability varies as a function of altitude. First, by dividing the whole surveillance region into cells, a probability map can be formed for each UAV indicating the probability of target existence within each cell. Then, we propose a distributed probability map updating model which includes the fusion of measurement information, information sharing among neighboring agents, information decay and transmission due to environmental changes such as the target movement. Furthermore, we formulate the target search problem as a multi-agent cooperative coverage control problem by optimizing the collective coverage area and the detection performance. The proposed map updating model and the cooperative control scheme are distributed, i.e., assuming that each agent only communicates with its neighbors within its communication range. Finally, the effectiveness of the proposed algorithms is illustrated by simulation. PMID:24865884

The Cyclic Nature of Problem Solving: An Emergent Multidimensional Problem-Solving Framework

ERIC Educational Resources Information Center

Carlson, Marilyn P.; Bloom, Irene

2005-01-01

This paper describes the problem-solving behaviors of 12 mathematicians as they completed four mathematical tasks. The emergent problem-solving framework draws on the large body of research, as grounded by and modified in response to our close observations of these mathematicians. The resulting "Multidimensional Problem-Solving Framework" has four…

New techniques to measure cliff change from historical oblique aerial photographs and structure-from-motion photogrammetry

USGS Publications Warehouse

Warrick, Jonathan; Ritchie, Andy; Adelman, Gabrielle; Adelman, Ken; Limber, Patrick W.

2017-01-01

Oblique aerial photograph surveys are commonly used to document coastal landscapes. Here it is shown that adequate overlap may exist in these photographic records to develop topographic models with Structure-from-Motion (SfM) photogrammetric techniques. Using photographs of Fort Funston, California, from the California Coastal Records Project, imagery were combined with ground control points in a four-dimensional analysis that produced topographic point clouds of the study area’s cliffs for 5 years spanning 2002 to 2010. Uncertainty was assessed by comparing point clouds with airborne LIDAR data, and these uncertainties were related to the number and spatial distribution of ground control points used in the SfM analyses. With six or more ground control points, the root mean squared errors between the SfM and LIDAR data were less than 0.30 m (minimum 1⁄4 0.18 m), and the mean systematic error was less than 0.10 m. The SfM results had several benefits over traditional airborne LIDAR in that they included point coverage on vertical- to-overhanging sections of the cliff and resulted in 10–100 times greater point densities. Time series of the SfM results revealed topographic changes, including landslides, rock falls, and the erosion of landslide talus along the Fort Funston beach. Thus, it was concluded that SfM photogrammetric techniques with historical oblique photographs allow for the extraction of useful quantitative information for mapping coastal topography and measuring coastal change. The new techniques presented here are likely applicable to many photograph collections and problems in the earth sciences.

Tethered Vehicle Control and Tracking System

NASA Technical Reports Server (NTRS)

North, David D. (Inventor); Aull, Mark J. (Inventor)

2017-01-01

A kite system includes a kite and a ground station. The ground station includes a sensor that can be utilized to determine an angular position and velocity of the kite relative to the ground station. A controller utilizes a fuzzy logic control system to autonomously fly the kite. The system may include a ground station having powered winding units that generate power as the lines to the kite are unreeled. The control system may be configured to fly the kite in a crosswind trajectory to increase line tension for power generation. The sensors for determining the position of the kite are preferably ground-based.

Tethered Vehicle Control and Tracking System

NASA Technical Reports Server (NTRS)

North, David D. (Inventor); Aull, Mark J. (Inventor)

2014-01-01

A kite system includes a kite and a ground station. The ground station includes a sensor that can be utilized to determine an angular position and velocity of the kite relative to the ground station. A controller utilizes a fuzzy logic control system to autonomously fly the kite. The system may include a ground station having powered winding units that generate power as the lines to the kite are unreeled. The control system may be configured to fly the kite in a crosswind trajectory to increase line tension for power generation. The sensors for determining the position of the kite are preferably ground-based.

Model-based reasoning in SSF ECLSS

NASA Technical Reports Server (NTRS)

Miller, J. K.; Williams, George P. W., Jr.

1992-01-01

The interacting processes and reconfigurable subsystems of the Space Station Freedom Environmental Control and Life Support System (ECLSS) present a tremendous technical challenge to Freedom's crew and ground support. ECLSS operation and problem analysis is time-consuming for crew members and difficult for current computerized control, monitoring, and diagnostic software. These challenges can be at least partially mitigated by the use of advanced techniques such as Model-Based Reasoning (MBR). This paper will provide an overview of MBR as it is being applied to Space Station Freedom ECLSS. It will report on work being done to produce intelligent systems to help design, control, monitor, and diagnose Freedom's ECLSS. Specifically, work on predictive monitoring, diagnosability, and diagnosis, with emphasis on the automated diagnosis of the regenerative water recovery and air revitalization processes will be discussed.

Trace Analysis of Heavy Metals in Ground Waters of Vijayawada Industrial Area

ERIC Educational Resources Information Center

Tadiboyina, Ravisankar; Ptsrk, Prasada Rao

2016-01-01

In recent years, the new environmental problem are arising due to industrial hazard wastage, global climate change, ground water contamination and etc., gives an attention to protect environment.one of the major source of contamination of ground water is improper discharge of industrial effluents these effluents contains so many heavy metals which…

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....

Testing the sensitivity of pumpage to increases in surficial aquifer system heads in the Cypress Creek well-field area, West-Central Florida : an optimization technique

USGS Publications Warehouse

Yobbi, Dann K.

2002-01-01

Tampa Bay depends on ground water for most of the water supply. Numerous wetlands and lakes in Pasco County have been impacted by the high demand for ground water. Central Pasco County, particularly the area within the Cypress Creek well field, has been greatly affected. Probable causes for the decline in surface-water levels are well-field pumpage and a decade-long drought. Efforts are underway to increase surface-water levels by developing alternative sources of water supply, thus reducing the quantity of well-field pumpage. Numerical ground-water flow simulations coupled with an optimization routine were used in a series of simulations to test the sensitivity of optimal pumpage to desired increases in surficial aquifer system heads in the Cypress Creek well field. The ground-water system was simulated using the central northern Tampa Bay ground-water flow model. Pumping solutions for 1987 equilibrium conditions and for a transient 6-month timeframe were determined for five test cases, each reflecting a range of desired target recovery heads at different head control sites in the surficial aquifer system. Results are presented in the form of curves relating average head recovery to total optimal pumpage. Pumping solutions are sensitive to the location of head control sites formulated in the optimization problem and as expected, total optimal pumpage decreased when desired target head increased. The distribution of optimal pumpage for individual production wells also was significantly affected by the location of head control sites. A pumping advantage was gained for test-case formulations where hydraulic heads were maximized in cells near the production wells, in cells within the steady-state pumping center cone of depression, and in cells within the area of the well field where confining-unit leakance is the highest. More water was pumped and the ratio of head recovery per unit decrease in optimal pumpage was more than double for test cases where hydraulic heads are maximized in cells located at or near the production wells. Additionally, the ratio of head recovery per unit decrease in pumpage was about three times more for the area where confining-unit leakance is the highest than for other leakance zone areas of the well field. For many head control sites, optimal heads corresponding to optimal pumpage deviated from the desired target recovery heads. Overall, pumping solutions were constrained by the limiting recovery values, initial head conditions, and by upper boundary conditions of the ground-water flow model.

Application of the conjugate-gradient method to ground-water models

USGS Publications Warehouse

Manteuffel, T.A.; Grove, D.B.; Konikow, Leonard F.

1984-01-01

The conjugate-gradient method can solve efficiently and accurately finite-difference approximations to the ground-water flow equation. An aquifer-simulation model using the conjugate-gradient method was applied to a problem of ground-water flow in an alluvial aquifer at the Rocky Mountain Arsenal, Denver, Colorado. For this application, the accuracy and efficiency of the conjugate-gradient method compared favorably with other available methods for steady-state flow. However, its efficiency relative to other available methods depends on the nature of the specific problem. The main advantage of the conjugate-gradient method is that it does not require the use of iteration parameters, thereby eliminating this partly subjective procedure. (USGS)

Science objectives for ground- and space-based optical/IR interferometry

NASA Technical Reports Server (NTRS)

Ridgway, Stephen T.

1992-01-01

Ground-based interferometry will make spectacular strides in the next decade. However, it will always be limited by the turbulence of the terrestrial atmosphere. Some of the most exciting and subtle problems may only be addressed from a stable platform above the atmosphere. The lunar surface offers such a platform, nearly ideal in many respects. Once built, such a telescope array will not only resolve key fundamental problems, but will revolutionize virtually every topic in observational astronomy. Estimates of the possible performance of lunar and ground-based interferometers of the 21st century shows that the lunar interferometer reaches the faintest sources of all wavelengths, but has the most significant advantage in the infrared.

Geology and water resources of Winnebago County, Wisconsin

USGS Publications Warehouse

Olcott, Perry C.

1966-01-01

Sources or water in Winnebago County include surface water from the Fox and Wolf Rivers and their associated lakes, and ground water from sandstone, dolomite, and sand and gravel deposits. Surface water is hard and generally requires treatment, but is then suitable for municipal and most industrial uses. Pollution is only a local problem in the lakes and rivers, but algae are present in most of the lakes. Ground water in Winnebago County is hard to very hard, and dissolved iron is a problem in a large area of the county. A saline-water zone borders the eastern edge of the county and underlies the areas of concentrated pumpage at Neenah-Menasha and Oshkosh. A thick, southeastward-dipping sandstone aquifer, yielding as much as 1,000 gallons per minute to municipal and industrial wells, underlies Winnebago County. A dolomite aquifer in the eastern and southern part of the county yields as much as 50 gallons per minute to wells. Sand and gravel layers and lenses in preglacial bedrock channels, in northwestern Winnebago County and in the upper Fox River valley, yield as much as 50 gallons per minute to wells. Present water problems in the county include algae and local pollution in the Lake Winnebago Pool, iron in water from the sandstone aquifer, and saline ground Water in the eastern part of the county. Potential problems include rapid decline of water levels because of interference between closely spaced wells, migration of saline ground water toward areas of pumping, surface-water pollution from inadequate sewage and industrial-waste process plants, and ground-water pollution in dolomite formations. Development of the water resources of the county should follow a comprehensive plan which takes into consideration all aspects of water use. Dispersal of wells, especially extending toward the west from the heavily pumped Neenah-Menasha and Oshkosh areas, is recommended to reduce water-level declines and to avoid saline water. Supplemental use of ground water is recmmended for municipal expansion of water facilities and to reduce the algae treatment problem of water from the Lake Winnebago Pool.

Natural Resources Study to Determine Causes and Alternative Solutions to the Siltation and Pollution Problems of Big Stone Lake. Task 1.

DTIC Science & Technology

1974-08-01

have been collected in and around the watershed area. Eight of these were species of the genus Aedes and one was Culiseta inornata, a known carrier...needing or See Table 3 663,00C- possibly needing control Other Sources Land runoff Snow mlt and storm water Water courses ditches and 57,000 carrying...than those for the lower portion. 3. Ground Water a. Supply: Part of the water from rain, melting snow , wet- lands, lakes, and streams in the Big Stone

Material Science

NASA Image and Video Library

2003-01-22

Video images sent to the ground allow scientists to watch the behavior of the bubbles as they control the melting and freezing of the material during the Pore Formation and Mobility Investigation (PFMI) in the Microgravity Science Glovebox aboard the International Space Station. While the investigation studies the way that metals behave at the microscopic scale on Earth -- and how voids form -- the experiment uses a transparent material called succinonitrile that behaves like a metal to study this problem. The bubbles do not float to the top of the material in microgravity, so they can study their interactions.

Proceedings of the Meeting of the Special Interest Group on Control Theory (1st) Held at Aberdeen Proving Ground, Maryland on 22 May 80,

DTIC Science & Technology

1980-05-01

elements that will form the candi- existing targets are given In References 2 and S. date GIC systems; The effectiveness of any missile system Is con- a...authority is specified as that a sensor using some form of pattern recogni- tion may be required. The problem is to find or ot , .- I K (2, begin...have the requirements imposed by an advanced G&C system. been derived so that the resulting formulation is deliberately cast in a form particularly

High assurance SPIRAL

NASA Astrophysics Data System (ADS)

Franchetti, Franz; Sandryhaila, Aliaksei; Johnson, Jeremy R.

2014-06-01

In this paper we introduce High Assurance SPIRAL to solve the last mile problem for the synthesis of high assurance implementations of controllers for vehicular systems that are executed in today's and future embedded and high performance embedded system processors. High Assurance SPIRAL is a scalable methodology to translate a high level specification of a high assurance controller into a highly resource-efficient, platform-adapted, verified control software implementation for a given platform in a language like C or C++. High Assurance SPIRAL proves that the implementation is equivalent to the specification written in the control engineer's domain language. Our approach scales to problems involving floating-point calculations and provides highly optimized synthesized code. It is possible to estimate the available headroom to enable assurance/performance trade-offs under real-time constraints, and enables the synthesis of multiple implementation variants to make attacks harder. At the core of High Assurance SPIRAL is the Hybrid Control Operator Language (HCOL) that leverages advanced mathematical constructs expressing the controller specification to provide high quality translation capabilities. Combined with a verified/certified compiler, High Assurance SPIRAL provides a comprehensive complete solution to the efficient synthesis of verifiable high assurance controllers. We demonstrate High Assurance SPIRALs capability by co-synthesizing proofs and implementations for attack detection and sensor spoofing algorithms and deploy the code as ROS nodes on the Landshark unmanned ground vehicle and on a Synthetic Car in a real-time simulator.

Ground Systems Development Environment (GSDE) interface requirements and prototyping plan

NASA Technical Reports Server (NTRS)

Church, Victor E.; Philips, John; Bassman, Mitchell; Williams, C.

1990-01-01

This report describes the data collection and requirements analysis effort of the Ground System Development Environment (GSDE) Interface Requirements study. It identifies potential problems in the interfaces among applications and processors in the heterogeneous systems that comprises the GSDE. It describes possible strategies for addressing those problems. It also identifies areas for further research and prototyping to demonstrate the capabilities and feasibility of those strategies and defines a plan for building the necessary software prototypes.

Mechanisms in wing-in-ground effect aerodynamics

NASA Astrophysics Data System (ADS)

Jones, Marvin Alan

An aircraft in low-level flight experiences a large increase in lift and a marked reduction in drag, compared with flight at altitude. This phenomenon is termed the 'wing-in-ground' effect. In these circumstances a region of high pressure is created beneath the aerofoil, and a pressure difference is set up between its upper and lower surfaces. A pressure difference is not permitted at the trailing edge and therefore a mechanism must exist which allows the pressures above and below to adjust themselves to produce a continuous pressure field in the wake. It is the study of this mechanism and its role in the aerodynamics of low-level flight that forms the basis of our investigation. We begin in Chapter 2 by considering the flow past a thin aero-foil moving at moderate distances from the ground, the typical ground clearance a being of order unity. The aforementioned mechanism is introduced and described in detail in the context of this inviscid problem. Chapter 3 considers the same flow for large and small ground clearances and in the later case shows that the flow solution beneath the aerofoil takes on a particularly simple form. In this case the lift is shown to increase as a-1. In Chapter 4 we focus on the flow past the trailing edge of an aerofoil moving even nearer the ground, with the ground just outside the boundary layer. We show that in this case our asymptotic theory for small a is consistent with a 'triple-deck' approach to the problem which incorporates ground effects via a new pressure-displacement law. The triple-deck ground-interference problem is stated and solved. In Chapter 5 we investigate the case where the aerofoil is so near the ground that the ground is inside the boundary layer. Here the moving ground interacts with the aerofoil in a fully viscous way and the non-linear boundary layer equations hold along the entire length of the aerofoil. Again a pressure difference at the trailing edge is not permitted and this produces upstream adjustment back to the leading edge. Regions of reversed flow can occur and their effects, with regard to downforce production and racing car undertray design, are considered. In Chapter 6 we consider 'wing-in-tunnel' effects.

Results of quality-control sampling of water, bed sediment, and tissue in the Western Lake Michigan Drainages study unit of the National Water-Quality Assessment Program

USGS Publications Warehouse

Fitzgerald, S.A.

1997-01-01

This report contains the quality control results of the Western Lake Michigan Drainages study unit of the National Water Quality Assessment Program. Quality control samples were collected in the same manner and contemporaneously with environmental samples during the first highintensity study phase in the unit (1992 through 1995) and amounted to approximately 15 percent of all samples collected. The accuracy and precision of hundreds of chemical analyses of surface and ground-water, bed sediment, and tissue was determined through the collection and analysis of field blanks, field replicates and splits, matrix spikes, and surrogates. Despite the several detections of analytes in the field blanks, the concentrations of most constituents in the environmental samples will likely be an order of magnitude or higher than those in the blanks. However, frequent detections, and high concentrations, of dissolved organic carbon (DOC) in several surface and ground-water blanks are probably significant with respect to commonly measured environmental concentrations, and the environmental data will have to be qualified accordingly. The precision of sampling of water on a percent basis, as determined from replicates and splits, was generally proportional to the concentration of the constituents, with constituents present in relatively high concentrations generally having less sampling variability than those with relatively low concentrations. In general, analytes with relatively high variability between replicates were present at concentrations near the reporting limit or were associated with relatively small absolute concentration differences, or both. Precision of replicates compared to that for splits in bed sediment samples was similar, thus eliminating sampling as a major source of variability in analyte concentrations. In the case the phthalates in bed sediment, contamination in either the field or laboratory could have caused the relatively large variability between replicate samples and between split samples.Variability of analyte concentrations in tissue samples was relatively low, being 29 percent or less for all constituents. Recoveries of most laboratory schedule 2001/2010 pesticide spike compounds in surfacewater samples were reasonably good. Low intrinsic method recovery resulted in relatively low recovery forp,p'-DDE, metribuzin, and propargite. In the case of propargite, decomposition with the environmental sample matrices was also indicated. Recoveries of two compounds, cyanazine and thiobencarb, might have been biased high due to interferences. The one laboratory schedule 2050/2051 field matrix pesticide spike indicated numerous operational problems with this method that biased recoveries either low or high. Recoveries of pesticides from both pesticide schedules in field spikes of ground-water samples generally were similar to those of field matrix spikes of surface- water samples. High maximum recoveries were noted for tebuthiuron, disulfoton, DCPA, and permethrin, which indicates the possible presence of interferents in the matrices for these compounds. Problems in the recoveries of pesticides on schedule 2050/2051 from ground-water samples generally were the same as those for surfacewater samples. Recoveries of VOCs in field matrix spikes were reasonable when consideration was given for the use of the micropipettor that delivered only about 80 percent on average of the nominal mass of spiked analytes. Finally, the recoveries of most surrogate compounds in surface and ground-water samples were reasonable. Problems in sample handling (for example, spillage) were likely not the cause of any of the low recoveries of spiked compounds.

Electrostatic antenna space environment interaction study

NASA Technical Reports Server (NTRS)

Katz, I.

1981-01-01

The interactions of the electrostatic antenna with the space environment in both low Earth orbit and geosynchronous orbit are investigated. It is concluded that the electrostatically controlled membrane mirror is a viable concept for space applications. However, great care must be taken to enclose the high voltage electrodes in a Faraday cage structure to separate the high voltage region from the ambient plasma. For this reason, metallized cloth is not acceptable as a membrane material. Conventional spacecraft charging at geosynchronous orbit should not be a problem provided ancillary structures (such as booms) are given nonnegligible conductivity and adequate grounding. Power loss due to plasma electrons entering the high field region is a potentially serious problem. In low earth orbit any opening whatever in the Faraday cage is likely to produce an unacceptable power drain.

Surface charge method for molecular surfaces with curved areal elements I. Spherical triangles

NASA Astrophysics Data System (ADS)

Yu, Yi-Kuo

2018-03-01

Parametrizing a curved surface with flat triangles in electrostatics problems creates a diverging electric field. One way to avoid this is to have curved areal elements. However, charge density integration over curved patches appears difficult. This paper, dealing with spherical triangles, is the first in a series aiming to solve this problem. Here, we lay the ground work for employing curved patches for applying the surface charge method to electrostatics. We show analytically how one may control the accuracy by expanding in powers of the the arc length (multiplied by the curvature). To accommodate not extremely small curved areal elements, we have provided enough details to include higher order corrections that are needed for better accuracy when slightly larger surface elements are used.

Mature data transport and command management services for the Space Station

NASA Technical Reports Server (NTRS)

Carper, R. D.

1986-01-01

The duplex space/ground/space data services for the Space Station are described. The need to separate the uplink data service functions from the command functions is discussed. Command management is a process shared by an operation control center and a command management system and consists of four functions: (1) uplink data communications, (2) management of the on-board computer, (3) flight resource allocation and management, and (4) real command management. The new data service capabilities provided by microprocessors, ground and flight nodes, and closed loop and open loop capabilities are studied. The need for and functions of a flight resource allocation management service are examined. The system is designed so only users can access the system; the problems encountered with open loop uplink access are analyzed. The procedures for delivery of operational, verification, computer, and surveillance and monitoring data directly to users are reviewed.

Turn Your Schoolgrounds into an Environmental Study Area.

ERIC Educational Resources Information Center

Buetler, Larry, Ed.

1993-01-01

Describes activities that utilize the school grounds as a context to study environmental problems. Activities include surveying the grounds, map making, tree identification, study of plant and animal life, soil studies, and conservation and beautification projects. (MDH)

Ground-water program in Alabama

USGS Publications Warehouse

LaMoreaux, P.E.

1955-01-01

Several recent years of drought have emphasized the importance of Alabama's ground-water supplies, a matter of concern to us all.  So far we have been blessed in Alabama with ample ground-water, although a combination of increased use, waste, pollution, and drought has brought about critical local water shortages.  These problems serve as a fair warning of what lies ahead if we do not take the necessary steps to obtan adequate knowledge of our ground-water resources.

Potential health consequences of ground-water contamination by nitrates in Nebraska.

PubMed

Weisenburger, D D

1993-01-01

Ground water serves as the primary source of drinking water for nearly all of rural Nebraska. However, ground-water contamination by nitrates, largely due to the use of fertilizers, is an increasing problem. In an ecologic study, the author found that counties characterized by high fertilizer usage and significant ground-water contamination by nitrates also had a high incidence of non-Hodgkin's lymphoma. Other potential health effects of nitrates in drinking water are also discussed.

Ground-water models as a management tool in Florida

USGS Publications Warehouse

Hutchinson, C.B.

1984-01-01

Highly sophisticated computer models provide powerful tools for analyzing historic data and for simulating future water levels, water movement, and water chemistry under stressed conditions throughout the ground-water system in Florida. Models that simulate the movement of heat and subsidence of land in response to aquifer pumping also have potential for application to hydrologic problems in the State. Florida, with 20 ground-water modeling studies reported since 1972, has applied computer modeling techniques to a variety of water-resources problems. Models in Florida generally have been used to provide insight to problems of water supply, contamination, and impact on the environment. The model applications range from site-specific studies, such as estimating contamination by wastewater injection at St. Petersburg, to a regional model of the entire State that may be used to assess broad-scale environmental impact of water-resources development. Recently, groundwater models have been used as management tools by the State regulatory authority to permit or deny development of water resources. As modeling precision, knowledge, and confidence increase, the use of ground-water models will shift more and more toward regulation of development and enforcement of environmental laws. (USGS)

System and method for transferring telemetry data between a ground station and a control center

NASA Technical Reports Server (NTRS)

Ray, Timothy J. (Inventor); Ly, Vuong T. (Inventor)

2012-01-01

Disclosed herein are systems, computer-implemented methods, and tangible computer-readable media for coordinating communications between a ground station, a control center, and a spacecraft. The method receives a call to a simple, unified application programmer interface implementing communications protocols related to outer space, when instruction relates to receiving a command at the control center for the ground station generate an abstract message by agreeing upon a format for each type of abstract message with the ground station and using a set of message definitions to configure the command in the agreed upon format, encode the abstract message to generate an encoded message, and transfer the encoded message to the ground station, and perform similar actions when the instruction relates to receiving a second command as a second encoded message at the ground station from the control center and when the determined instruction type relates to transmitting information to the control center.

Improving Dorsal Stream Function in Dyslexics by Training Figure/Ground Motion Discrimination Improves Attention, Reading Fluency, and Working Memory

PubMed Central

Lawton, Teri

2016-01-01

There is an ongoing debate about whether the cause of dyslexia is based on linguistic, auditory, or visual timing deficits. To investigate this issue three interventions were compared in 58 dyslexics in second grade (7 years on average), two targeting the temporal dynamics (timing) of either the auditory or visual pathways with a third reading intervention (control group) targeting linguistic word building. Visual pathway training in dyslexics to improve direction-discrimination of moving test patterns relative to a stationary background (figure/ground discrimination) significantly improved attention, reading fluency, both speed and comprehension, phonological processing, and both auditory and visual working memory relative to controls, whereas auditory training to improve phonological processing did not improve these academic skills significantly more than found for controls. This study supports the hypothesis that faulty timing in synchronizing the activity of magnocellular with parvocellular visual pathways is a fundamental cause of dyslexia, and argues against the assumption that reading deficiencies in dyslexia are caused by phonological deficits. This study demonstrates that visual movement direction-discrimination can be used to not only detect dyslexia early, but also for its successful treatment, so that reading problems do not prevent children from readily learning. PMID:27551263

A Critical Survey of Optimization Models for Tactical and Strategic Aspects of Air Traffic Flow Management

NASA Technical Reports Server (NTRS)

Bertsimas, Dimitris; Odoni, Amedeo

1997-01-01

This document presents a critical review of the principal existing optimization models that have been applied to Air Traffic Flow Management (TFM). Emphasis will be placed on two problems, the Generalized Tactical Flow Management Problem (GTFMP) and the Ground Holding Problem (GHP), as well as on some of their variations. To perform this task, we have carried out an extensive literature review that has covered more than 40 references, most of them very recent. Based on the review of this emerging field our objectives were to: (i) identify the best available models; (ii) describe typical contexts for applications of the models; (iii) provide illustrative model formulations; and (iv) identify the methodologies that can be used to solve the models. We shall begin our presentation below by providing a brief context for the models that we are reviewing. In Section 3 we shall offer a taxonomy and identify four classes of models for review. In Sections 4, 5, and 6 we shall then review, respectively, models for the Single-Airport Ground Holding Problem, the Generalized Tactical FM P and the Multi-Airport Ground Holding Problem (for the definition of these problems see Section 3 below). In each section, we identify the best available models and discuss briefly their computational performance and applications, if any, to date. Section 7 summarizes our conclusions about the state of the art.

Comfort-oriented vehicle suspension design with skyhook inerter configuration

NASA Astrophysics Data System (ADS)

Hu, Yinlong; Chen, Michael Z. Q.; Sun, Yonghui

2017-09-01

This paper is concerned with the comfort-oriented vehicle suspension design problem by using a skyhook inerter configuration. The rationale of the skyhook inerter is to use a grounded inerter to virtually increase the sprung mass of a vehicle, as it is analytically demonstrated that increasing the sprung mass can always improve the ride comfort performance. Semi-active means to realize the skyhook inerter configuration are investigated by using semi-active inerters. Three control laws, that is the on-off control, the anti-chatter on-off control, and the continuous control, are proposed for the semi-active inerter to approximate the skyhook inerter. Numerical simulations are performed to demonstrate the effectiveness and performances of these control laws. It is shown that the semi-active realizations of the skyhook inerter by using the proposed control laws can achieve over 10% improvement compared with the traditional strut, and similar performances are obtained for these control laws, with slight differences with respect to different static stiffnesses of the suspension system.

A Grounded Theory Study on Journeying through the Shield to Sacredness: "Ni'hokaa' Diyin Dine'e Idliini Dolzin"

ERIC Educational Resources Information Center

Garrity, Geraldine

2013-01-01

In doing a grounded theory study, the researcher does not identify a hypothesis, formulate research questions, or state a specific problem at the beginning of the research. Grounded theory research begins with data collection, minimizing preconceptions about outcomes to the greatest extent possible. I began my research with this attitude of not…

Structural impact response for assessing railway vibration induced on buildings

NASA Astrophysics Data System (ADS)

Kouroussis, Georges; Mouzakis, Harris P.; Vogiatzis, Konstantinos E.

2018-03-01

Over the syears, the rapid growth in railway infrastructure has led to numerous environmental challenges. One such significant issue, particularly in urban areas, is ground-borne vibration. A common source of ground-borne vibration is caused by local defects (e.g. rail joints, switches, turnouts, etc.) that generate large amplitude excitations at isolated locations. Modelling these excitation sources is particularly challenging and requires the use of complex and extensive computational efforts. For some situations, the use of experiments and measured data offers a rapid way to estimate the effect of such defects and to evaluate the railway vibration levels using a scoping approach. In this paper, the problem of railway-induced ground vibrations is presented along with experimental studies to assess the ground vibration and ground borne noise levels, with a particular focus on the structural response of sensitive buildings. The behaviour of particular building foundations is evaluated through experimental data collected in Brussels Region, by presenting the expected frequency responses for various types of buildings, taking into account both the soil-structure interaction and the tramway track response. A second study is dedicated to the Athens metro, where transmissibility functions are used to analyse the effect of various Athenian building face to metro network trough comprehensive measurement campaigns. This allows the verification of appropriate vibration mitigation measures. These benchmark applications based on experimental results have been proved to be efficient to treat a complex problem encountered in practice in urban areas, where the urban rail network interacts with important local defects and where the rise of railway ground vibration problems has clearly been identified.

Assessment of remote sensing technologies to discover and characterize waste sites

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

NONE

1992-03-11

This report presents details about waste management practices that are being developed using remote sensing techniques to characterize DOE waste sites. Once the sites and problems have been located and characterized and an achievable restoration and remediation program have been established, efforts to reclaim the environment will begin. Special problems to be considered are: concentrated waste forms in tanks and pits; soil and ground water contamination; ground safety hazards for workers; and requirement for long-term monitoring.

A Program of Ground-Based Astronomy to Complement Einstein Observations.

DTIC Science & Technology

1982-11-30

Astronomy D T I C i CO-,,, Uv I,. WA TOPE: -. Gary A. Cbanan Assistant Professor of Phy.3[cs i t0V.l.., 1982 %30𔃼 0 ii CONTENTS Page A. REPORT DOCUMENTATION...block number) A total of eight ground-based astronomical observing programs were carried out in pursuit of a multiwavelength approach to a number of...astro- physical problems. Synthesis of these results with existing X-ray data led to considerable progress on problems of the emission mechanisms and

OpenSatKit Enables Quick Startup for CubeSat Missions

NASA Technical Reports Server (NTRS)

McComas, David; Melton, Ryan

2017-01-01

The software required to develop, integrate, and operate a spacecraft is substantial regardless of whether its a large or small satellite. Even getting started can be a monumental task. To solve this problem, NASAs Core Flight System (cFS), NASA's 42 spacecraft dynamics simulator, and Ball Aerospaces COSMOS ground system have been integrated together into a kit called OpenSatKit that provides a complete and open source software solution for starting a new satellite mission. Users can have a working system with flight software, dynamics simulation, and a ground command and control system up and running within hours.Every satellite mission requires three primary categories of software to function. The first is Flight Software (FSW) which provides the onboard control of the satellites and its payload(s). NASA's cFS provides a great platform for developing this software. Second, while developing a satellite on earth, it is necessary to simulate the satellites orbit, attitude, and actuators, to ensure that the systems that control these aspects will work correctly in the real environment. NASAs 42 simulator provides these functionalities. Finally, the ground has to be able to communicate with the satellite, monitor its performance and health, and display its data. Additionally, test scripts have to be written to verify the system on the ground. Ball Aerospace's COSMOS command and control system provides this functionality. Once the OpenSatKit is up and running, the next step is to customize the platform and get it running on the end target. Starting from a fully working system makes porting the cFS from Linux to a users platform much easier. An example Raspberry Pi target is included in the kit so users can gain experience working with a low cost hardware target. All users can benefit from OpenSatKit but the greatest impact and benefits will be to SmallSat missions with constrained budgets and small software teams. This paper describes OpenSatKits system design, the steps necessary to run the system to target the Raspberry Pi, and future plans. OpenSatKit is a free fully functional spacecraft software system that we hope will greatly benefit the SmallSat community.

Motion Planning and Task Assignment for Unmanned Aerial Vehicles Cooperating with Unattended Ground Sensors

DTIC Science & Technology

2014-10-24

problem was formalized as the Dubins travelling salesman problem (TSP). In the second phase of the research we have...given constraints on its motion. This problem was formalized as the Dubins travelling salesman problem (TSP). The contributions of the study in the... problem was formalized as the Dubins travelling salesman problem (TSP). The Dubins Travelling Salesperson Problem (DTSP) and its variants [8, 12,

Aircraft symmetric flight optimization. [gradient techniques for supersonic aircraft control

NASA Technical Reports Server (NTRS)

Falco, M.; Kelley, H. J.

1973-01-01

Review of the development of gradient techniques and their application to aircraft optimal performance computations in the vertical plane of flight. Results obtained using the method of gradients are presented for attitude- and throttle-control programs which extremize the fuel, range, and time performance indices subject to various trajectory and control constraints, including boundedness of engine throttle control. A penalty function treatment of state inequality constraints which generally appear in aircraft performance problems is outlined. Numerical results for maximum-range, minimum-fuel, and minimum-time climb paths for a hypothetical supersonic turbojet interceptor are presented and discussed. In addition, minimum-fuel climb paths subject to various levels of ground overpressure intensity constraint are indicated for a representative supersonic transport. A variant of the Gel'fand-Tsetlin 'method of ravines' is reviewed, and two possibilities for further development of continuous gradient processes are cited - namely, a projection version of conjugate gradients and a curvilinear search.

Superconducting spin valves controlled by spiral re-orientation in B20-family magnets

NASA Astrophysics Data System (ADS)

Pugach, N. G.; Safonchik, M.; Champel, T.; Zhitomirsky, M. E.; Lähderanta, E.; Eschrig, M.; Lacroix, C.

2017-10-01

We propose a superconducting spin-triplet valve, which consists of a superconductor and an itinerant magnetic material, with the magnet showing an intrinsic non-collinear order characterized by a wave vector that may be aligned in a few equivalent preferred directions under the control of a weak external magnetic field. Re-orienting the spiral direction allows one to controllably modify long-range spin-triplet superconducting correlations, leading to spin-valve switching behavior. Our results indicate that the spin-valve effect may be noticeable. This bilayer may be used as a magnetic memory element for cryogenic nanoelectronics. It has the following advantages in comparison to superconducting spin valves proposed previously: (i) it contains only one magnetic layer, which may be more easily fabricated and controlled; (ii) its ground states are separated by a potential barrier, which solves the "half-select" problem of the addressed switch of memory elements.

Research on flight stability performance of rotor aircraft based on visual servo control method

NASA Astrophysics Data System (ADS)

Yu, Yanan; Chen, Jing

2016-11-01

control method based on visual servo feedback is proposed, which is used to improve the attitude of a quad-rotor aircraft and to enhance its flight stability. Ground target images are obtained by a visual platform fixed on aircraft. Scale invariant feature transform (SIFT) algorism is used to extract image feature information. According to the image characteristic analysis, fast motion estimation is completed and used as an input signal of PID flight control system to realize real-time status adjustment in flight process. Imaging tests and simulation results show that the method proposed acts good performance in terms of flight stability compensation and attitude adjustment. The response speed and control precision meets the requirements of actual use, which is able to reduce or even eliminate the influence of environmental disturbance. So the method proposed has certain research value to solve the problem of aircraft's anti-disturbance.

Optical Control of a Nuclear Spin in Diamond

NASA Astrophysics Data System (ADS)

Levonian, David; Goldman, Michael; Degreve, Kristiaan; Choi, Soonwon; Markham, Matthew; Twitchen, Daniel; Lukin, Mikhail

2017-04-01

The nitrogen-vacancy (NV) center in diamond has emerged as a promising candidate for quantum information and quantum communication applications. The NV center's potential as a quantum register is due to the long coherence time of its spin-triplet electronic ground state, the optical addressability of its electronic transitions, and the presence of nearby ancillary nuclear spins. The NV center's electronic spin and nearby nuclear spins are most commonly manipulated using applied microwave and RF fields, but this approach would be difficult to scale up for use with an array of NV-based quantum registers. In this context, all-optical manipulation would be more scalable, technically simpler, and potentially faster. Although all-optical control of the electronic spin has been demonstrated, it is an outstanding problem for the nuclear spins. Here, we use an optical Raman scheme to implement nuclear spin-specific control of the electronic spin and coherent control of the 14N nuclear spin.

Process Upsets Involving Trace Contaminant Control Systems

NASA Technical Reports Server (NTRS)

Graf, John C.; Perry, Jay; Wright, John; Bahr, Jim

2000-01-01

Paradoxically, trace contaminant control systems that suffer unexpected upsets and malfunctions can release hazardous gaseous contaminants into a spacecraft cabin atmosphere causing potentially serious toxicological problems. Trace contaminant control systems designed for spaceflight typically employ a combination of adsorption beds and catalytic oxidation reactors to remove organic and inorganic trace contaminants from the cabin atmosphere. Interestingly, the same design features and attributes which make these systems so effective for purifying a spacecraft's atmosphere can also make them susceptible to system upsets. Cabin conditions can be contributing causes of phenomena such as adsorbent "rollover" and catalyst poisoning can alter a systems performance and in some in stances release contamination into the cabin. Evidence of these phenomena has been observed both in flight and during ground-based tests. The following discussion describes specific instances of system upsets found in trace contaminant control systems, groups these specific upsets into general hazard classifications, and recommends ways to minimize these hazards.

Distributed pheromone-based swarming control of unmanned air and ground vehicles for RSTA

NASA Astrophysics Data System (ADS)

Sauter, John A.; Mathews, Robert S.; Yinger, Andrew; Robinson, Joshua S.; Moody, John; Riddle, Stephanie

2008-04-01

The use of unmanned vehicles in Reconnaissance, Surveillance, and Target Acquisition (RSTA) applications has received considerable attention recently. Cooperating land and air vehicles can support multiple sensor modalities providing pervasive and ubiquitous broad area sensor coverage. However coordination of multiple air and land vehicles serving different mission objectives in a dynamic and complex environment is a challenging problem. Swarm intelligence algorithms, inspired by the mechanisms used in natural systems to coordinate the activities of many entities provide a promising alternative to traditional command and control approaches. This paper describes recent advances in a fully distributed digital pheromone algorithm that has demonstrated its effectiveness in managing the complexity of swarming unmanned systems. The results of a recent demonstration at NASA's Wallops Island of multiple Aerosonde Unmanned Air Vehicles (UAVs) and Pioneer Unmanned Ground Vehicles (UGVs) cooperating in a coordinated RSTA application are discussed. The vehicles were autonomously controlled by the onboard digital pheromone responding to the needs of the automatic target recognition algorithms. UAVs and UGVs controlled by the same pheromone algorithm self-organized to perform total area surveillance, automatic target detection, sensor cueing, and automatic target recognition with no central processing or control and minimal operator input. Complete autonomy adds several safety and fault tolerance requirements which were integrated into the basic pheromone framework. The adaptive algorithms demonstrated the ability to handle some unplanned hardware failures during the demonstration without any human intervention. The paper describes lessons learned and the next steps for this promising technology.

Ground-water problems in highway construction and maintenance

USGS Publications Warehouse

Rasmussen, W.C.; Haigler, L.B.

1953-01-01

This report discusses the occurrence of ground water in relation to certain problems in highway construction and maintenance. These problems are: the subdrainage of roads; quicksand; the arrest of soil creep in road cuts; the construction of lower and larger culverts necessitated by the farm-drainage program; the prevention of failure of bridge abutments and retaining walls; and the water-cement ratio of sub-water-table concrete. Although the highway problems and suggested solutions are of general interest, they are considered with special reference to the State of Delaware, in relation to the geology of that State. The new technique of soil stabilization by electroosmosis is reviewed in the hope that it might find application here in road work and pile setting, field application by the Germans and Russians is reviewed.

Keep It in Proportion.

ERIC Educational Resources Information Center

Snider, Richard G.

1985-01-01

The ratio factors approach involves recognizing a given fraction, then multiplying so that units cancel. This approach, which is grounded in concrete operational thinking patterns, provides a standard for science ratio and proportion problems. Examples are included for unit conversions, mole problems, molarity, speed/density problems, and…

24 CFR 3285.204 - Ground moisture control.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 24 Housing and Urban Development 5 2011-04-01 2011-04-01 false Ground moisture control. 3285.204... URBAN DEVELOPMENT MODEL MANUFACTURED HOME INSTALLATION STANDARDS Site Preparation § 3285.204 Ground... materials, a vapor retarder must be installed to cover the ground under the home, unless the home is...

14 CFR 25.415 - Ground gust conditions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Ground gust conditions. 25.415 Section 25... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Control Surface and System Loads § 25.415 Ground... ground gusts and taxiing downwind: (1) The control system between the stops nearest the surfaces and the...

24 CFR 3285.204 - Ground moisture control.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Ground moisture control. 3285.204... URBAN DEVELOPMENT MODEL MANUFACTURED HOME INSTALLATION STANDARDS Site Preparation § 3285.204 Ground... materials, a vapor retarder must be installed to cover the ground under the home, unless the home is...

14 CFR 25.415 - Ground gust conditions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Ground gust conditions. 25.415 Section 25... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Control Surface and System Loads § 25.415 Ground... ground gusts and taxiing downwind: (1) The control system between the stops nearest the surfaces and the...

Ground-water quality assessment of the central Oklahoma Aquifer, Oklahoma; project description

USGS Publications Warehouse

Christenson, S.C.; Parkhurst, D.L.

1987-01-01

In April 1986, the U.S. Geological Survey began a pilot program to assess the quality of the Nation's surface-water and ground-water resources. The program, known as the National Water-Quality Assessment (NAWQA) program, is designed to acquire and interpret information about a variety of water-quality issues. The Central Oklahoma aquifer project is one of three ground-water pilot projects that have been started. The NAWQA program also incudes four surface-water pilot projects. The Central Oklahoma aquifer project, as part of the pilot NAWQA program, will develop and test methods for performing assessments of ground-water quality. The objectives of the Central Oklahoma aquifer assessment are: (1) To investigate regional ground-water quality throughout the aquifer in the manner consistent with the other pilot ground-water projects, emphasizing the occurrence and distribution of potentially toxic substances in ground water, including trace elements, organic compounds, and radioactive constituents; (2) to describe relations between ground-water quality, land use, hydrogeology, and other pertinent factors; and (3) to provide a general description of the location, nature, and possible causes of selected prevalent water-quality problems within the study unit; and (4) to describe the potential for water-quality degradation of ground-water zones within the study unit. The Central Oklahoma aquifer, which includes in descending order the Garber Sandstone and Wellington Formation, the Chase Group, the Council Grove Group, the Admire Group, and overlying alluvium and terrace deposits, underlies about 3,000 square miles of central Oklahoma and is used extensively for municipal, industrial, commercial, and domestic water supplies. The aquifer was selected for study by the NAWQA program because it is a major source for water supplies in central Oklahoma and because it has several known or suspected water-quality problems. Known problems include concentrations of arsenic, chromium, selenium, and gross-alpha activity that exceed drinking-water standards. Suspected problems include possible contamination of the aquifer by oil-field brines and drilling fluids, pesticides, industrial chemicals, septic-tank effluent, fertilizers, and leakage from sewage systems and underground tanks used for storage of hydrocarbons. There are four major components of the Central Oklahoma aquifer project. The first component is the collection and analysis of existing information, including chemical, hydrologic, and land-use data. The second component is the geohydrologic and geochemical investigations of the aquifer flow system. The third component is the sampling for a wide variety of inorganic, organic, and radioactive constituents as part a regional survey that will produce a consistent set of data among all ground-water pilot projects. These data can be used to: (1) Define regional ground-water quality within the Central Oklahoma aquifer, and (2) compare water quality in the Central Oklahoma aquifer to the water quality in the other ground-water study units of the NAWQA program. The fourth component is topical studies that will address, in more detail, some of the major water-quality issues pertaining to the aquifer.

Problems Related to Computer Ethics: Origins of the Problems and Suggested Solutions

ERIC Educational Resources Information Center

Kuzu, Abdullah

2009-01-01

Increasing use of information and communication technologies (ICTs) help individuals to solve several everyday problems, which used to be harder, more complicated and time consuming. Even though ICTs provide individuals with many advantages, they might also serve as grounds for several societal and ethical problems which vary in accordance with…

Mooring and ground handling rigid airships

NASA Technical Reports Server (NTRS)

Walker, H., Jr.

1975-01-01

The problems of mooring and ground handling rigid airships are discussed. A brief history of Mooring and Ground Handling Rigid Airships from July 2, 1900 through September 1, 1939 is included. Also a brief history of ground handling developments with large U. S. Navy nonrigid airships between September 1, 1939 and August 31, 1962 is included wherein developed equipment and techniques appear applicable to future large rigid airships. Finally recommendations are made pertaining to equipment and procedures which appear desirable and feasible for future rigid airship programs.

Joint inversion of geophysical data using petrophysical clustering and facies deformation wth the level set technique

NASA Astrophysics Data System (ADS)

Revil, A.

2015-12-01

Geological expertise and petrophysical relationships can be brought together to provide prior information while inverting multiple geophysical datasets. The merging of such information can result in more realistic solution in the distribution of the model parameters, reducing ipse facto the non-uniqueness of the inverse problem. We consider two level of heterogeneities: facies, described by facies boundaries and heteroegenities inside each facies determined by a correlogram. In this presentation, we pose the geophysical inverse problem in terms of Gaussian random fields with mean functions controlled by petrophysical relationships and covariance functions controlled by a prior geological cross-section, including the definition of spatial boundaries for the geological facies. The petrophysical relationship problem is formulated as a regression problem upon each facies. The inversion of the geophysical data is performed in a Bayesian framework. We demonstrate the usefulness of this strategy using a first synthetic case for which we perform a joint inversion of gravity and galvanometric resistivity data with the stations located at the ground surface. The joint inversion is used to recover the density and resistivity distributions of the subsurface. In a second step, we consider the possibility that the facies boundaries are deformable and their shapes are inverted as well. We use the level set approach to perform such deformation preserving prior topological properties of the facies throughout the inversion. With the help of prior facies petrophysical relationships and topological characteristic of each facies, we make posterior inference about multiple geophysical tomograms based on their corresponding geophysical data misfits. The method is applied to a second synthetic case showing that we can recover the heterogeneities inside the facies, the mean values for the petrophysical properties, and, to some extent, the facies boundaries using the 2D joint inversion of gravity and galvanometric resistivity data. For this 2D synthetic example, we note that the position of the facies are well-recovered except far from the ground surfce where the sensitivity is too low. The figure shows the evolution of the shape of the facies during the inversion itertion by iteration.

Powered Descent Guidance with General Thrust-Pointing Constraints

NASA Technical Reports Server (NTRS)

Carson, John M., III; Acikmese, Behcet; Blackmore, Lars

2013-01-01

The Powered Descent Guidance (PDG) algorithm and software for generating Mars pinpoint or precision landing guidance profiles has been enhanced to incorporate thrust-pointing constraints. Pointing constraints would typically be needed for onboard sensor and navigation systems that have specific field-of-view requirements to generate valid ground proximity and terrain-relative state measurements. The original PDG algorithm was designed to enforce both control and state constraints, including maximum and minimum thrust bounds, avoidance of the ground or descent within a glide slope cone, and maximum speed limits. The thrust-bound and thrust-pointing constraints within PDG are non-convex, which in general requires nonlinear optimization methods to generate solutions. The short duration of Mars powered descent requires guaranteed PDG convergence to a solution within a finite time; however, nonlinear optimization methods have no guarantees of convergence to the global optimal or convergence within finite computation time. A lossless convexification developed for the original PDG algorithm relaxed the non-convex thrust bound constraints. This relaxation was theoretically proven to provide valid and optimal solutions for the original, non-convex problem within a convex framework. As with the thrust bound constraint, a relaxation of the thrust-pointing constraint also provides a lossless convexification that ensures the enhanced relaxed PDG algorithm remains convex and retains validity for the original nonconvex problem. The enhanced PDG algorithm provides guidance profiles for pinpoint and precision landing that minimize fuel usage, minimize landing error to the target, and ensure satisfaction of all position and control constraints, including thrust bounds and now thrust-pointing constraints.

Research field of fire technology in Finland

NASA Astrophysics Data System (ADS)

Loikkanen, P.; Holm, C.

1987-02-01

The goal of the study is to give an overview of the whole diversified research field of fire technology and its problems. For this reason the research subjects have been grouped so that the responsibilities of different authorities, the legislation and specifications, various fields of technology, areas of industry, and groups of products could all be found as clearly as possible. The field has been divided into nine sub-areas. They are: general grounds, fire physics and chemistry, structural fire prevention, textiles and furnishings, devices for heating and other use, detection, fire fighting and rescue, quality control, and special problems. The sub-areas have been divided into 34 main subjects and these, excluding those of special problems, further into as many as 117 subject groups. Characteristics and problems of the sub-areas and the main subjects have been described. The subject groups have been characterized by key words and concepts which outline the projects. No concrete research projects and programs have, however, been directly suggested because their extent and contents depend essentially on financing and other available resources.

Quantum Optimization of Fully Connected Spin Glasses

NASA Astrophysics Data System (ADS)

Venturelli, Davide; Mandrà, Salvatore; Knysh, Sergey; O'Gorman, Bryan; Biswas, Rupak; Smelyanskiy, Vadim

2015-07-01

Many NP-hard problems can be seen as the task of finding a ground state of a disordered highly connected Ising spin glass. If solutions are sought by means of quantum annealing, it is often necessary to represent those graphs in the annealer's hardware by means of the graph-minor embedding technique, generating a final Hamiltonian consisting of coupled chains of ferromagnetically bound spins, whose binding energy is a free parameter. In order to investigate the effect of embedding on problems of interest, the fully connected Sherrington-Kirkpatrick model with random ±1 couplings is programmed on the D-Wave TwoTM annealer using up to 270 qubits interacting on a Chimera-type graph. We present the best embedding prescriptions for encoding the Sherrington-Kirkpatrick problem in the Chimera graph. The results indicate that the optimal choice of embedding parameters could be associated with the emergence of the spin-glass phase of the embedded problem, whose presence was previously uncertain. This optimal parameter setting allows the performance of the quantum annealer to compete with (and potentially outperform, in the absence of analog control errors) optimized simulated annealing algorithms.

A projection gradient method for computing ground state of spin-2 Bose–Einstein condensates

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

Wang, Hanquan, E-mail: hanquan.wang@gmail.com; Yunnan Tongchang Scientific Computing and Data Mining Research Center, Kunming, Yunnan Province, 650221

In this paper, a projection gradient method is presented for computing ground state of spin-2 Bose–Einstein condensates (BEC). We first propose the general projection gradient method for solving energy functional minimization problem under multiple constraints, in which the energy functional takes real functions as independent variables. We next extend the method to solve a similar problem, where the energy functional now takes complex functions as independent variables. We finally employ the method into finding the ground state of spin-2 BEC. The key of our method is: by constructing continuous gradient flows (CGFs), the ground state of spin-2 BEC can bemore » computed as the steady state solution of such CGFs. We discretized the CGFs by a conservative finite difference method along with a proper way to deal with the nonlinear terms. We show that the numerical discretization is normalization and magnetization conservative and energy diminishing. Numerical results of the ground state and their energy of spin-2 BEC are reported to demonstrate the effectiveness of the numerical method.« less

The changing pattern of ground-water development on Long Island, New York

USGS Publications Warehouse

Heath, Ralph C.; Foxworthy, B.L.; Cohen, Philip M.

1966-01-01

Ground-water development on Long Island has followed a pattern that has reflected changing population trends, attendant changes in the use and disposal of water, and the response of the hydrologic system to these changes. The historic pattern of development has ranged from individually owned shallow wells tapping glacial deposits to large-capacity public-supply wells tapping deep artesian aquifers. Sewage disposal has ranged from privately owned cesspools to modern large-capacity sewage-treatment plants discharging more than 70 mgd of water to the sea. At present (1965), different parts of long Island are characterized by different stages of ground-water development. In parts of Suffolk County in eastern long Island, development is similar to the earliest historical stages. Westward toward New York City, ground-water development becomes more intensive and complex, and the attendant problems become more acute. The alleviation of present problems and those that arise in the future will require management decisions based on the soundest possible knowledge of the hydrologic system, including an understanding of the factors involved in the changing pattern of ground-water development on the island.

On the Relationship between Fourier and Response Spectra: Implications for the Adjustment of Empirical Ground-Motion Prediction Equations (GMPEs)

NASA Astrophysics Data System (ADS)

Bora, Sanjay; Scherbaum, Frank; Kuehn, Nicolas; Stafford, Peter

2016-04-01

Often, scaling of response spectral amplitudes, (e.g., spectral acceleration) obtained from empirical ground motion prediction equations (GMPEs), with respect to commonly used seismological parameters such as magnitude, distance and site condition is assumed/referred to be representing a similar scaling of Fourier spectral amplitudes. For instance, the distance scaling of response spectral amplitudes is related with the geometrical spreading of seismic waves. Such comparison of scaling of response spectral amplitudes with that of corresponding Fourier spectral amplitudes is motivated by that, the functional forms of response spectral GMPEs are often derived using the concepts borrowed from Fourier spectral modeling of ground motion. As these GMPEs are subsequently calibrated with empirical observations, this may not appear to pose any major problems in the prediction of ground motion for a particular earthquake scenario. However, the assumption that the Fourier spectral concepts persist for response spectra can lead to undesirable consequences when it comes to the adjustment of response spectral GMPEs to represent conditions not covered in the original empirical data set. In this context, a couple of important questions arise, e.g., what are the distinctions and/or similarities between Fourier and response spectra of ground-motions? And, if they are different, then what is the mechanism responsible for such differences and how do adjustments that are made to FAS manifest in response spectra? We explore the relationship between the Fourier and response spectrum of ground motion by using random vibration theory (RVT). With a simple Brune (1970, 1971) source model, RVT-generated acceleration spectra for a fixed magnitude and distance scenario are used. The RVT analyses reveal that the scaling of low oscillator-frequency response spectral ordinates can be treated as being equivalent to the scaling of the corresponding Fourier spectral ordinates. However, the high oscillator-frequency response spectral ordinates are controlled by a rather wide-band of Fourier spectral ordinates. In fact, the peak ground acceleration (PGA), counter to the popular perception that it is a reflection of the high-frequency characteristics of ground motion, is controlled by the entire Fourier spectrum of ground-motion. Finally, it is demonstrated, how an adjustment made in Fourier spectral amplitudes is different or similar to the same adjustment made in the response spectral amplitudes. For this purpose, two cases: adjustments to the stress parameter (Δσ) (source term) and to attributes reflecting site response (V s-κ0) are considered.

The Ozone Problem | Ground-level Ozone | New England | US ...

EPA Pesticide Factsheets

2017-04-10

Many factors impact ground-level ozone development, including temperature, wind speed and direction, time of day, and driving patterns. Due to its dependence on weather conditions, ozone is typically a summertime pollutant and a chief component of summertime smog.

Arsenic in Ground Water of the United States

MedlinePlus

... a hard problem : Geotimes Newsmagazine of the Earth Sciences, v.46 no.11, p.34-36. (2001) DATA Arsenic in ground-water resources of the United States : U.S. Geological Survey Fact Sheet 063-00. (2000) A retrospective analysis on ...

INVESTIGATION OF GROUND WATER CONTAMINATION NEAR PAVILLION, WYOMING

EPA Science Inventory

In response to complaints by domestic well owners regarding objectionable taste and odor problems in well water, the U.S. Environmental Protection Agency initiated a ground water investigation near the town of Pavillion, Wyoming under authority of the Comprehensive Environmental ...

Collaboration and Conflict Resolution in Education.

ERIC Educational Resources Information Center

Melamed, James C.; Reiman, John W.

2000-01-01

Presents guidelines for resolving conflicts between educators and parents. Participants should seek different perspectives, not "truths," consider the common ground, define an effective problem-solving procedure, adopt ground rules for discussion, address issues, identify interests and positive intentions, develop options, select arrangements, and…

Space station structures and dynamics test program

NASA Technical Reports Server (NTRS)

Moore, Carleton J.; Townsend, John S.; Ivey, Edward W.

1987-01-01

The design, construction, and operation of a low-Earth orbit space station poses unique challenges for development and implementation of new technology. The technology arises from the special requirement that the station be built and constructed to function in a weightless environment, where static loads are minimal and secondary to system dynamics and control problems. One specific challenge confronting NASA is the development of a dynamics test program for: (1) defining space station design requirements, and (2) identifying the characterizing phenomena affecting the station's design and development. A general definition of the space station dynamic test program, as proposed by MSFC, forms the subject of this report. The test proposal is a comprehensive structural dynamics program to be launched in support of the space station. The test program will help to define the key issues and/or problems inherent to large space structure analysis, design, and testing. Development of a parametric data base and verification of the math models and analytical analysis tools necessary for engineering support of the station's design, construction, and operation provide the impetus for the dynamics test program. The philosophy is to integrate dynamics into the design phase through extensive ground testing and analytical ground simulations of generic systems, prototype elements, and subassemblies. On-orbit testing of the station will also be used to define its capability.

An unmanned ground vehicle for landmine remediation

NASA Astrophysics Data System (ADS)

Wasson, Steven R.; Guilberto, Jose; Ogg, Wade; Wedeward, Kevin; Bruder, Stephen; El-Osery, Aly

2004-09-01

Anti-tank (AT) landmines slow down and endanger military advances and present sizeable humanitarian problems. The remediation of these mines by direct human intervention is both dangerous and costly. The Intelligent Systems & Robotics Group (ISRG) at New Mexico Tech has provided a partial solution to this problem by developing an Unmanned Ground Vehicle (UGV) to remediate these mines without endangering human lives. This paper presents an overview of the design and operation of this UGV. Current results and future work are also described herein. To initiate the remediation process the UGV is given the GPS coordinates of previously detected landmines. Once the UGV autonomously navigates to an acceptable proximity of the landmine, a remote operator acquires control over a wireless network link using a joystick on a base station. Utilizing two cameras mounted on the UGV, the operator is able to accurately position the UGV directly over the landmine. The UGV houses a self-contained drill system equipped with its own processing resources, sensors, and actuators. The drill system deploys a neutralizing device over the landmine to neutralize it. One such device, developed by Science Applications International Corporation (SAIC), employs incendiary materials to melt through the container of the landmine and slowly burn the explosive material, thereby safely and remotely disabling the landmine.

Mineral exploration and soil analysis using in situ neutron activation

USGS Publications Warehouse

Senftle, F.E.; Hoyte, A.F.

1966-01-01

A feasibility study has been made to operate by remote control an unshielded portable positive-ion accelerator type neutron source to induce activities in the ground or rock by "in situ" neutron irradiation. Selective activation techniques make it possible to detect some thirty or more elements by irradiating the ground for periods of a few minutes with either 3-MeV or 14-MeV neutrons. The depth of penetration of neutrons, the effect of water content of the soil on neutron moderation, gamma ray attenuation in the soil and other problems are considered. The analysis shows that, when exploring for most elements of economic interest, the reaction 2H(d,n)3He yielding ??? 3-MeV neutrons is most practical to produce a relatively uniform flux of neutrons of less than 1 keV to a depth of 19???-20???. Irradiation with high energy neutrons (??? 14 MeV) can also be used and may be better suited for certain problems. However, due to higher background and lower sensitivity for the heavy minerals, it is not a recommended neutron source for general exploration use. Preliminary experiments have been made which indicate that neutron activation in situ is feasible for a mineral exploration or qualititative soil analysis. ?? 1976.

Automation technology for aerospace power management

NASA Technical Reports Server (NTRS)

Larsen, R. L.

1982-01-01

The growing size and complexity of spacecraft power systems coupled with limited space/ground communications necessitate increasingly automated onboard control systems. Research in computer science, particularly artificial intelligence has developed methods and techniques for constructing man-machine systems with problem-solving expertise in limited domains which may contribute to the automation of power systems. Since these systems perform tasks which are typically performed by human experts they have become known as Expert Systems. A review of the current state of the art in expert systems technology is presented, and potential applications in power systems management are considered. It is concluded that expert systems appear to have significant potential for improving the productivity of operations personnel in aerospace applications, and in automating the control of many aerospace systems.

Progress Toward Generation of a Navier-Stokes Database for a Harrier in Ground Effect

NASA Technical Reports Server (NTRS)

Chaderjian, Neal M.; Ahmad, Jasim U.; Pandya, Shishir A.; Murman, Scott A.; Kwak, Dochan (Technical Monitor)

2002-01-01

The Harrier YAV-8B aircraft is capable of vertical and short-field take-off and landing (V/STOL) by directing its four exhaust nozzles toward the ground, or conventional flight by rotating its nozzles into a horizontal position. The British Royal Air Force and the United States Marine Corps have used this aircraft for more than 30 years to provide a quick reaction time for troop support, and reduce the need for long runways. The success of this powered-lift (PL) vehicle has also prompted the more recent design of the Joint Strike Fighter (JSF). However there are significant safety issues that must be addressed when operating a PL vehicle in close proximity to the ground. Hot Gas Ingestion (HGI) by the inlets can result in a rapid loss of powered lift; and high-speed jet flows along the ground plane can induce low pressures underneath the vehicle, causing a 'suck-down' effect. Under these conditions, departure from controlled flight may occur. Moreover, unsteady ground vortices and jet fountains can affect the aircraft,s controllability and its proximity to ground troops. The viscous, time-dependent flow fields of PL vehicles are difficult to accurately and efficiently predict using Computational Fluid Dynamics (CFD). A number of researchers have used the time-dependent Reynolds-averaged Navier-Stokes (RANS) equations to compute flows for single and multiple jets in a cross-flow. A few have added some geometric complexity to the problem by computing flows for jet-augmented delta wings near a ground plane. Smith et.al. computed for the first time a single RANS solution about a simplified Harrier. This geometry included a fuselage, wing, leading edge root extension (LERX), inlets, and exhaust nozzles. All of these investigations cite two practical problems with computing these flows: 1) the need for improved solution accuracy; and, 2) the need for faster solution methods. We view the need for faster solution methods as key to improving the solution accuracy and making this class of computation more routine. One can hardly refine grids, explore the use of advanced turbulence models, and generate databases when it takes weeks of dedicated computer time for a single solution. Chaderjian, Ahmad, Pandya, and Murman have focused on reducing the time-to-solution for this very difficult and complex problem through process automation and exploitation of parallel computing. They began with the Harrier geometry reported, and added a deflected wing flap and empennage for greater realism. To date more than 80 solutions have been carried out. This paper will describe this process and progress made in reducing the time required to generate a simple longitudinal force and moment database for a Harrier in ground effect. It shows a typical snap-shot from an unsteady streakline animation, where fluid particles are colored by temperature. The ground vortex and a jet-fountain vortex are highlighted. It also shows a similar streakline image, where HGI occurs due to the vehicle in close proximity to the ground. It is show the mean lift coefficient as a function of angle of attack and height. The angle of attack range was 4 deg less than or = alpha less than or = 10 deg with an increment of 1 degree, and the height range was 10 ft less than or = h less than or = 30ft with an increment of 5 feet. This 35 solution database was extended to over 2500 cases using a monotone cubic-spline interpolation procedure. The suck-down effect (reduction of lift near the ground) is highlighted in the figure. The "cushion effect," the conventional reduction of lift as the vehicle moves out of ground effect, is also indicated. All 35 RANS solutions were obtained using 952 Silicon Graphics Origin 2000 and 3000 processors in dedicated mode for one week. Typically, 112 processors were assigned to each case. Some other cases used fewer processors to utilize all available CPUS. The final paper will report on the automation of the solution process, including: grid generation, job monitoring, solution completion criteria, and post processing. Moreover, improvements in parallel efficiency for a dual time-step algorithm for the RANS equations will also be presented. Results will be discussed in detail using unsteady streakline flow visualization to correlate unsteady flow structures with dominant aerodynamic frequencies. The stability derivatives, CL, and CL, will also be presented.

Theoretical study of the effect of ground proximity on the induced efficiency of helicopter rotors

NASA Technical Reports Server (NTRS)

Heyson, H. H.

1977-01-01

A study of rotors in forward flight within ground effect showed that the ground-induced interference is an upwash and a decrease in forward velocity. The interference velocities are large, oppose the normal flow through the rotor, and have large effects on the induced efficiency. Hovering with small ground clearances may result in significant blade stall. As speed is increased from hover in ground effect, power initially increases rather than decreases. At very low heights above the ground, the power requirements become nonlinear with speed as a result of the streamwise interference. The streamwise interference becomes greater as the wake approaches the ground and eventually distorts the wake to form the ground vortex which contributes to certain observed directional stability problems.

Automated Conflict Resolution, Arrival Management and Weather Avoidance for ATM

NASA Technical Reports Server (NTRS)

Erzberger, H.; Lauderdale, Todd A.; Chu, Yung-Cheng

2010-01-01

The paper describes a unified solution to three types of separation assurance problems that occur in en-route airspace: separation conflicts, arrival sequencing, and weather-cell avoidance. Algorithms for solving these problems play a key role in the design of future air traffic management systems such as NextGen. Because these problems can arise simultaneously in any combination, it is necessary to develop integrated algorithms for solving them. A unified and comprehensive solution to these problems provides the foundation for a future air traffic management system that requires a high level of automation in separation assurance. The paper describes the three algorithms developed for solving each problem and then shows how they are used sequentially to solve any combination of these problems. The first algorithm resolves loss-of-separation conflicts and is an evolution of an algorithm described in an earlier paper. The new version generates multiple resolutions for each conflict and then selects the one giving the least delay. Two new algorithms, one for sequencing and merging of arrival traffic, referred to as the Arrival Manager, and the other for weather-cell avoidance are the major focus of the paper. Because these three problems constitute a substantial fraction of the workload of en-route controllers, integrated algorithms to solve them is a basic requirement for automated separation assurance. The paper also reviews the Advanced Airspace Concept, a proposed design for a ground-based system that postulates redundant systems for separation assurance in order to achieve both high levels of safety and airspace capacity. It is proposed that automated separation assurance be introduced operationally in several steps, each step reducing controller workload further while increasing airspace capacity. A fast time simulation was used to determine performance statistics of the algorithm at up to 3 times current traffic levels.

Launching AI in NASA ground systems

NASA Technical Reports Server (NTRS)

Perkins, Dorothy C.; Truszkowski, Walter F.

1990-01-01

This paper will discuss recent operational successes in implementing expert systems to support the complex functions of NASA mission control systems at the Goddard Space Flight Center, including fault detection and diagnosis for real time and engineering analysis functions in the Cosmic Background Explorer and Gamma Ray Observatory missions and automation of resource planning and scheduling functions for various missions. It will also discuss ongoing developments and prototypes that will lead to increasingly sophisticated applications of artificial intelligence. These include the use of neural networks to perform telemetry monitoring functions, the implementation of generic expert system shells that can be customized to telemetry handling functions specific to NASA control centers, the applications of AI in training and user support, the long-term potential of implementing systems based around distributed, cooperative problem solving, and the use of AI to control and assist system development activities.

Scheduler for monitoring objects orbiting earth using satellite-based telescopes

DOEpatents

Olivier, Scot S; Pertica, Alexander J; Riot, Vincent J; De Vries, Willem H; Bauman, Brian J; Nikolaev, Sergei; Henderson, John R; Phillion, Donald W

2015-04-28

An ephemeris refinement system includes satellites with imaging devices in earth orbit to make observations of space-based objects ("target objects") and a ground-based controller that controls the scheduling of the satellites to make the observations of the target objects and refines orbital models of the target objects. The ground-based controller determines when the target objects of interest will be near enough to a satellite for that satellite to collect an image of the target object based on an initial orbital model for the target objects. The ground-based controller directs the schedules to be uploaded to the satellites, and the satellites make observations as scheduled and download the observations to the ground-based controller. The ground-based controller then refines the initial orbital models of the target objects based on the locations of the target objects that are derived from the observations.

Monitoring objects orbiting earth using satellite-based telescopes

DOEpatents

Olivier, Scot S.; Pertica, Alexander J.; Riot, Vincent J.; De Vries, Willem H.; Bauman, Brian J.; Nikolaev, Sergei; Henderson, John R.; Phillion, Donald W.

2015-06-30

An ephemeris refinement system includes satellites with imaging devices in earth orbit to make observations of space-based objects ("target objects") and a ground-based controller that controls the scheduling of the satellites to make the observations of the target objects and refines orbital models of the target objects. The ground-based controller determines when the target objects of interest will be near enough to a satellite for that satellite to collect an image of the target object based on an initial orbital model for the target objects. The ground-based controller directs the schedules to be uploaded to the satellites, and the satellites make observations as scheduled and download the observations to the ground-based controller. The ground-based controller then refines the initial orbital models of the target objects based on the locations of the target objects that are derived from the observations.

The 1980 Aircraft Safety and Operating Problems, Part 2

NASA Technical Reports Server (NTRS)

Stickle, J. W. (Compiler)

1981-01-01

Terminal area operations, avionics and human factors, atmospheric environment, and operating problems and potential solutions are discussed. Other topics include flight experiences, ground operations, and acoustics and noise reduction.

Deformation mechanisms in a coal mine roadway in extremely swelling soft rock.

PubMed

Li, Qinghai; Shi, Weiping; Yang, Renshu

2016-01-01

The problem of roadway support in swelling soft rock was one of the challenging problems during mining. For most geological conditions, combinations of two or more supporting approaches could meet the requirements of most roadways; however, in extremely swelling soft rock, combined approaches even could not control large deformations. The purpose of this work was to probe the roadway deformation mechanisms in extremely swelling soft rock. Based on the main return air-way in a coal mine, deformation monitoring and geomechanical analysis were conducted, as well as plastic zone mechanical model was analysed. Results indicated that this soft rock was potentially very swelling. When the ground stress acted alone, the support strength needed in situ was not too large and combined supporting approaches could meet this requirement; however, when this potential released, the roadway would undergo permanent deformation. When the loose zone reached 3 m within surrounding rock, remote stress p ∞ and supporting stress P presented a linear relationship. Namely, the greater the swelling stress, the more difficult it would be in roadway supporting. So in this extremely swelling soft rock, a better way to control roadway deformation was to control the releasing of surrounding rock's swelling potential.

14 CFR 23.415 - Ground gust conditions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Ground gust conditions. 23.415 Section 23... and System Loads § 23.415 Ground gust conditions. (a) The control system must be investigated as follows for control surface loads due to ground gusts and taxiing downwind: (1) If an investigation of the...

Algorithms for Heterogeneous, Multiple Depot, Multiple Unmanned Vehicle Path Planning Problems

DOE PAGES

Sundar, Kaarthik; Rathinam, Sivakumar

2016-12-26

Unmanned vehicles, both aerial and ground, are being used in several monitoring applications to collect data from a set of targets. This article addresses a problem where a group of heterogeneous aerial or ground vehicles with different motion constraints located at distinct depots visit a set of targets. The vehicles also may be equipped with different sensors, and therefore, a target may not be visited by any vehicle. The objective is to find an optimal path for each vehicle starting and ending at its respective depot such that each target is visited at least once by some vehicle, the vehicle–targetmore » constraints are satisfied, and the sum of the length of the paths for all the vehicles is minimized. Two variants of this problem are formulated (one for ground vehicles and another for aerial vehicles) as mixed-integer linear programs and a branchand- cut algorithm is developed to compute an optimal solution to each of the variants. Computational results show that optimal solutions for problems involving 100 targets and 5 vehicles can be obtained within 300 seconds on average, further corroborating the effectiveness of the proposed approach.« less

Touchless attitude correction for satellite with constant magnetic moment

NASA Astrophysics Data System (ADS)

Ao, Hou-jun; Yang, Le-ping; Zhu, Yan-wei; Zhang, Yuan-wen; Huang, Huan

2017-09-01

Rescue of satellite with attitude fault is of great value. Satellite with improper injection attitude may lose contact with ground as the antenna points to the wrong direction, or encounter energy problems as solar arrays are not facing the sun. Improper uploaded command may set the attitude out of control, exemplified by Japanese Hitomi spacecraft. In engineering practice, traditional physical contact approaches have been applied, yet with a potential risk of collision and a lack of versatility since the mechanical systems are mission-specific. This paper puts forward a touchless attitude correction approach, in which three satellites are considered, one having constant dipole and two having magnetic coils to control attitude of the first. Particular correction configurations are designed and analyzed to maintain the target's orbit during the attitude correction process. A reference coordinate system is introduced to simplify the control process and avoid the singular value problem of Euler angles. Based on the spherical triangle basic relations, the accurate varying geomagnetic field is considered in the attitude dynamic mode. Sliding mode control method is utilized to design the correction law. Finally, numerical simulation is conducted to verify the theoretical derivation. It can be safely concluded that the no-contact attitude correction approach for the satellite with uniaxial constant magnetic moment is feasible and potentially applicable to on-orbit operations.

Thermal footprints in groundwater of central European cities

NASA Astrophysics Data System (ADS)

Bayer, P.; Menberg, K.; Blum, P.

2014-12-01

Atmospheric thermal pollution in densely populated areas is recognized as a severe problem with consequences for human health, and considerable efforts are being taken to mitigate heat stress in cities. However, anthropogenic activities also influence the thermal environment beneath the ground level, with commonly growing temperatures that affect groundwater ecology and geothermal use efficiency. In our work, we identify the controlling mechanisms for the long-term evolution of such urban heat islands. The shallow groundwater temperatures in several central European cities such as Cologne, Karlsruhe, Munich, Berlin and Zurich were mapped at high spatial and temporal resolution. Thermal anomalies were found to be highly heterogeneous with local hot spots showing temperatures of more than 20°C. Accordingly, these urban regions show a considerable groundwater warming in comparison to undisturbed temperatures of 8-11°C. Examination of potential heat sources by analytical modelling reveals that increased ground surface temperatures and basements of buildings act as dominant drivers for the anthropogenic heat input into the groundwater. The factors are revealed to be case-specific and they may have pronounced local or regional effects. Typical local factors are for example buried district heating networks. In selected cities we find that the average urban heat flux is around one order of magnitude higher than the elevated ground heat flux due to recent climate change. Additionally, such as observed in Zurich, naturally controlled temperature variations can be substantial and they are shown to wash out anthropogenic thermal footprints.

Nonlinear damping based semi-active building isolation system

NASA Astrophysics Data System (ADS)

Ho, Carmen; Zhu, Yunpeng; Lang, Zi-Qiang; Billings, Stephen A.; Kohiyama, Masayuki; Wakayama, Shizuka

2018-06-01

Many buildings in Japan currently have a base-isolation system with a low stiffness that is designed to shift the natural frequency of the building below the frequencies of the ground motion due to earthquakes. However, the ground motion observed during the 2011 Tohoku earthquake contained strong long-period waves that lasted for a record length of 3 min. To provide a novel and better solution against the long-period waves while maintaining the performance of the standard isolation range, the exploitation of the characteristics of nonlinear damping is proposed in this paper. This is motivated by previous studies of the authors, which have demonstrated that nonlinear damping can achieve desired performance over both low and high frequency regions and the optimal nonlinear damping force can be realized by closed loop controlled semi-active dampers. Simulation results have shown strong vibration isolation performance on a building model with identified parameters and have indicated that nonlinear damping can achieve low acceleration transmissibilities round the structural natural frequency as well as the higher ground motion frequencies that have been frequently observed during most earthquakes in Japan. In addition, physical building model based laboratory experiments are also conducted, The results demonstrate the advantages of the proposed nonlinear damping technologies over both traditional linear damping and more advanced Linear-Quadratic Gaussian (LQG) feedback control which have been used in practice to address building isolation system design and implementation problems. In comparison with the tuned-mass damper and other active control methods, the proposed solution offers a more pragmatic, low-cost, robust and effective alternative that can be readily installed into the base-isolation system of most buildings.

14 CFR 23.415 - Ground gust conditions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... and System Loads § 23.415 Ground gust conditions. (a) The control system must be investigated as... control system for ground gust loads is not required by paragraph (a)(2) of this section, but the applicant elects to design a part of the control system of these loads, these loads need only be carried...

Epistemological Grounds for Cybernetic Models.

ERIC Educational Resources Information Center

Khawam, Yves J.

1991-01-01

Addresses philosophical grounds for artificial intelligence (AI) and cybernetic models by investigating three epistemological views--realism, a priorism, and phenomenology--to determine the problems in information transfer between a model and the real world. It is suggested that phenomenology demonstrates the most promise for opening up…

GROUND-WATER MODEL TESTING: SYSTEMATIC EVALUATION AND TESTING OF CODE FUNCTIONALITY AND PERFORMANCE

EPA Science Inventory

Effective use of ground-water simulation codes as management decision tools requires the establishment of their functionality, performance characteristics, and applicability to the problem at hand. This is accomplished through application of a systematic code-testing protocol and...

Autonomous optimal trajectory design employing convex optimization for powered descent on an asteroid

NASA Astrophysics Data System (ADS)

Pinson, Robin Marie

Mission proposals that land spacecraft on asteroids are becoming increasingly popular. However, in order to have a successful mission the spacecraft must reliably and softly land at the intended landing site with pinpoint precision. The problem under investigation is how to design a propellant (fuel) optimal powered descent trajectory that can be quickly computed onboard the spacecraft, without interaction from ground control. The goal is to autonomously design the optimal powered descent trajectory onboard the spacecraft immediately prior to the descent burn for use during the burn. Compared to a planetary powered landing problem, the challenges that arise from designing an asteroid powered descent trajectory include complicated nonlinear gravity fields, small rotating bodies, and low thrust vehicles. The nonlinear gravity fields cannot be represented by a constant gravity model nor a Newtonian model. The trajectory design algorithm needs to be robust and efficient to guarantee a designed trajectory and complete the calculations in a reasonable time frame. This research investigates the following questions: Can convex optimization be used to design the minimum propellant powered descent trajectory for a soft landing on an asteroid? Is this method robust and reliable to allow autonomy onboard the spacecraft without interaction from ground control? This research designed a convex optimization based method that rapidly generates the propellant optimal asteroid powered descent trajectory. The solution to the convex optimization problem is the thrust magnitude and direction, which designs and determines the trajectory. The propellant optimal problem was formulated as a second order cone program, a subset of convex optimization, through relaxation techniques by including a slack variable, change of variables, and incorporation of the successive solution method. Convex optimization solvers, especially second order cone programs, are robust, reliable, and are guaranteed to find the global minimum provided one exists. In addition, an outer optimization loop using Brent's method determines the optimal flight time corresponding to the minimum propellant usage over all flight times. Inclusion of additional trajectory constraints, solely vertical motion near the landing site and glide slope, were evaluated. Through a theoretical proof involving the Minimum Principle from Optimal Control Theory and the Karush-Kuhn-Tucker conditions it was shown that the relaxed problem is identical to the original problem at the minimum point. Therefore, the optimal solution of the relaxed problem is an optimal solution of the original problem, referred to as lossless convexification. A key finding is that this holds for all levels of gravity model fidelity. The designed thrust magnitude profiles were the bang-bang predicted by Optimal Control Theory. The first high fidelity gravity model employed was the 2x2 spherical harmonics model assuming a perfect triaxial ellipsoid and placement of the coordinate frame at the asteroid's center of mass and aligned with the semi-major axes. The spherical harmonics model is not valid inside the Brillouin sphere and this becomes relevant for irregularly shaped asteroids. Then, a higher fidelity model was implemented combining the 4x4 spherical harmonics gravity model with the interior spherical Bessel gravity model. All gravitational terms in the equations of motion are evaluated with the position vector from the previous iteration, creating the successive solution method. Methodology success was shown by applying the algorithm to three triaxial ellipsoidal asteroids with four different rotation speeds using the 2x2 gravity model. Finally, the algorithm was tested using the irregularly shaped asteroid, Castalia.

Protein crystal growth results from shuttle flight 51-F

NASA Technical Reports Server (NTRS)

Bugg, C. E.

1985-01-01

The protein crystal growth (PCG) experiments run on 51-F were analyzed. It was found that: (1) sample stability is increased over that observed during the experiments on flight 51-D; (2) the dialysis experiments produced lysozyme crystals that were significantly larger than those obtained in our identical ground-based studies; (3) temperature fluctuations apparently caused problems during the crystallization experiments on 51-F; (4) it is indicated that teflon tape stabilizes droplets on the syringe tips; (5) samples survived during the reentry and landing in glass tips that were not stoppered with plungers; (6) from the ground-based studies, it was expected that equilibration should be complete within 2 to 4 days for all of these vapor-diffusion experiments, thus it appears that the vapor diffusion rates are somewhat slower under microgravity conditions; (7) drop tethering was highly successful, all four of the tethered drops were stable, even though they contained MPD solutions; (8) the PCG experiments on 51-F were done to assess the hardware and experimental procedures that are developed for future flights, when temperature control will be available. Lysozyme crystals obtained by microdialysis are considerably larger than those obtained on the ground, using the identical apparatus and procedures.

An in-flight simulation of approach and landing of a STOL transport with adverse ground effect

NASA Technical Reports Server (NTRS)

Ellis, D. R.

1976-01-01

The results of an in-flight simulation program undertaken to study the problems of landing a representative STOL transport in the presence of adverse ground effects are presented. Landings were performed with variations in ground effect magnitude, ground effect lag, and thrust response. Other variations covered the effects of augmented lift response, SAS-failures, turbulence, segmented approach, and flare warning. The basic STOL airplane required coordinated use of both stick and throttle for consistently acceptable landings, and the presence of adverse ground effects made the task significantly more difficult. Ground effect lag and good engine response gave noticeable improvement, as did augmented lift response.

Standing stability enhancement with an intelligent powered transfemoral prosthesis.

PubMed

Lawson, Brian Edward; Varol, Huseyin Atakan; Goldfarb, Michael

2011-09-01

The authors have developed a ground-adaptive standing controller for a powered knee and ankle prosthesis which is intended to enhance the standing stability of transfemoral amputees. The finite-state-based controller includes a ground-searching phase, a slope estimation phase, and a joint impedance modulation phase, which together enable the prosthesis to quickly conform to the ground and provide stabilizing assistance to the user. In order to assess the efficacy of the ground-adaptive standing controller, the control approach was implemented on a powered knee and ankle prosthesis, and experimental data were collected on an amputee subject for a variety of standing conditions. Results indicate that the controller can estimate the ground slope within ±1° over a range of ±15°, and that it can provide appropriate joint impedances for standing on slopes within this range.

Tug fleet and ground operations schedules and controls. Volume 2: part 1

NASA Technical Reports Server (NTRS)

1975-01-01

This Tug Fleet and Ground Operations Schedules and Controls Study addresses both ground operational data and technical requirements that span the Tug planning phase and operations phase. A similar study covering mission operations (by others) provides the complimentary flight operations details. The two studies provide the planning data requirements, resource allocation, and control milestones for supporting the requirements of the STS program. This Tug Fleet and Ground Operations Schedules and Controls Study incorporates the basic ground operations requirements and concepts provided by previous studies with the interrelationships of the planning, IUS transition, and Tug fleet operations phases. The interrelationships of these phases were studied as a system to optimize overall program benefits and minimize operational risk factors.

Outbreaks of Salmonella infections attributed to beef --United States, 1973-2011.

PubMed

Laufer, A S; Grass, J; Holt, K; Whichard, J M; Griffin, P M; Gould, L H

2015-07-01

Non-typhoidal Salmonella is estimated to be the most common bacterial cause of foodborne illness in the United States, causing an estimated one million domestically acquired foodborne illnesses annually. Recent, large outbreaks have highlighted the importance of ground beef as an important source of multidrug-resistant Salmonella. We analysed the epidemiology of salmonellosis outbreaks that were attributed to beef in the United States reported to the Centers for Disease Control and Prevention (CDC) from 1973 to 2011. During 1973-2011, of the 1965 outbreaks of Salmonella where a food vehicle was implicated, 96 were attributed to beef, accounting for 3684 illnesses. We observed a shift in the type of beef implicated in salmonellosis outbreaks, from roast to ground beef. Delicatessen-style roast beef cooked in commercial processing establishments was the predominant type during the 1970s and early 1980s; regulations on cooking and processing essentially eliminated this problem by 1987. Ground beef emerged as an important vehicle in the 2000s; it was implicated in 17 (45%) of the 38 beef-attributed outbreaks reported during 2002-2011. Although this emergence was likely due in part to increased participation in CDC's PulseNet, which was established in 1996, and proactive decisions by the United States Department of Agriculture's Food Safety and Inspection Service, stronger measures are needed to decrease contamination of ground beef with Salmonella.

Outbreaks of Salmonella Infections Attributed to Beef – United States, 1973–2011

PubMed Central

Laufer, A.S.; Grass, J.; Holt, K.; Whichard, J.M.; Griffin, P.M.; Gould, L.H.

2015-01-01

Summary Nontyphoidal salmonella is estimated to be the most common bacterial cause of foodborne illness in the United States, causing an estimated one million domestically-acquired foodborne illnesses annually. Recent, large outbreaks have highlighted the importance of ground beef as an important source of multidrug resistant salmonella. We analysed the epidemiology of salmonellosis outbreaks that were attributed to beef in the United States reported to the Centers for Disease Control and Prevention (CDC) from 1973 through 2011. During 1973–2011, of the 1965 outbreaks of salmonella where a food vehicle was implicated, 96 were attributed to beef, accounting for 3684 illnesses. We observed a shift in the type of beef implicated in salmonellosis outbreaks, from roast to ground beef. Delicatessen-style roast beef cooked in commercial processing establishments was the predominant type during the 1970s and early 1980s; regulations on cooking and processing essentially eliminated this problem by 1987. Ground beef emerged as an important vehicle in the 2000s; it was implicated in 17 (45%) of the 38 beef-attributed outbreaks reported during 2002–2011. Although this emergence was likely due in part to increased participation in CDC’s PulseNet, which was established in 1996, and proactive decisions by the United States Department of Agriculture’s Food Safety and Inspection Service, stronger measures are needed to decrease contamination of ground beef with salmonella. PMID:25427978

Sensitivity of grounding line dynamics to basal conditions

NASA Astrophysics Data System (ADS)

Gagliardini, O.; Brondex, J.; Chauveau, G.; Gillet-chaulet, F.; Durand, G.

2017-12-01

In the context of a warming climate, the dynamical contribution of Antarctica to future sea level rise is still tainted by high uncertainties. Among the processes entering these uncertainties is the link between basal hydrology, friction and grounding line dynamics. Recent works have shown how sensitive is the response of the grounding line retreat to the choice of the form of the friction law. Indeed, starting from the same initial state, grounding line retreat rates can range over almost two orders of magnitude depending on the friction law formulation.Here, we use a phenomenological law that depends on the water pressure and allows a continuous transition from a Weertman-type friction at low water pressure to a Coulomb-type friction at high water pressure. This friction law depends on two main parameters that control the Weertman and Coulomb regimes. The range of values for these two parameters is only weakly physically constrained, and it can be shown that, for a given basal shear stress, different couples of parameters can conduct to the same sliding velocity. In addition, we show that close to the grounding line where basal water pressure is high, determining these two parameters might conduct to an ill-posed inverse problem with no solution.The aim of this presentation is to discuss a methodology to guide the choice of the two friction parameters and explore the sensitivity of the grounding line dynamics to this initial choice. We present results obtained both on a synthetic configuration used by the Marine Ice Sheet Model Intercomparison exercise and for the Amundsen sea sector using the experiments proposed by InitMIP-Antarctica, the first exercise in a series of ISMIP6 ice-sheet model intercomparison activities.

Path Planning Algorithms for Autonomous Border Patrol Vehicles

NASA Astrophysics Data System (ADS)

Lau, George Tin Lam

This thesis presents an online path planning algorithm developed for unmanned vehicles in charge of autonomous border patrol. In this Pursuit-Evasion game, the unmanned vehicle is required to capture multiple trespassers on its own before any of them reach a target safe house where they are safe from capture. The problem formulation is based on Isaacs' Target Guarding problem, but extended to the case of multiple evaders. The proposed path planning method is based on Rapidly-exploring random trees (RRT) and is capable of producing trajectories within several seconds to capture 2 or 3 evaders. Simulations are carried out to demonstrate that the resulting trajectories approach the optimal solution produced by a nonlinear programming-based numerical optimal control solver. Experiments are also conducted on unmanned ground vehicles to show the feasibility of implementing the proposed online path planning algorithm on physical applications.

Marker optimization for facial motion acquisition and deformation.

PubMed

Le, Binh H; Zhu, Mingyang; Deng, Zhigang

2013-11-01

A long-standing problem in marker-based facial motion capture is what are the optimal facial mocap marker layouts. Despite its wide range of potential applications, this problem has not yet been systematically explored to date. This paper describes an approach to compute optimized marker layouts for facial motion acquisition as optimization of characteristic control points from a set of high-resolution, ground-truth facial mesh sequences. Specifically, the thin-shell linear deformation model is imposed onto the example pose reconstruction process via optional hard constraints such as symmetry and multiresolution constraints. Through our experiments and comparisons, we validate the effectiveness, robustness, and accuracy of our approach. Besides guiding minimal yet effective placement of facial mocap markers, we also describe and demonstrate its two selected applications: marker-based facial mesh skinning and multiresolution facial performance capture.

Ground-water management under the appropriation doctrine. Technical report

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

Ralston, D.; Bruhl, E.J.

The purpose of the research is to better understand the characteristics of ground-water management under the prior-appropriation doctrine in the western United States. The general objective is to summarize the legal and administrative controls on ground-water use in eight western states and to compare the impacts of these controls on ground water systems.

USGS California Water Science Center water programs in California

USGS Publications Warehouse

Shulters, Michael V.

2005-01-01

California is threatened by many natural hazards—fire, floods, landslides, earthquakes. The State is also threatened by longer-term problems, such as hydrologic effects of climate change, and human-induced problems, such as overuse of ground water and degradation of water quality. The threats and problems are intensified by increases in population, which has risen to nearly 36.8 million. For the USGS California Water Science Center, providing scientific information to help address hazards, threats, and hydrologic issues is a top priority. To meet the demands of a growing California, USGS scientific investigations are helping State and local governments improve emergency management, optimize resources, collect contaminant-source and -mobility information, and improve surface- and ground-water quality. USGS hydrologic studies and data collection throughout the State give water managers quantifiable and detailed scientific information that can be used to plan for development and to protect and more efficiently manage resources. The USGS, in cooperation with state, local, and tribal agencies, operates more than 500 instrument stations, which monitor streamflow, ground-water levels, and surface- and ground-water constituents to help protect water supplies and predict the threats of natural hazards. The following are some of the programs implemented by the USGS, in cooperation with other agencies, to obtain and analyze information needed to preserve California's environment and resources.

Mission planning optimization of video satellite for ground multi-object staring imaging

NASA Astrophysics Data System (ADS)

Cui, Kaikai; Xiang, Junhua; Zhang, Yulin

2018-03-01

This study investigates the emergency scheduling problem of ground multi-object staring imaging for a single video satellite. In the proposed mission scenario, the ground objects require a specified duration of staring imaging by the video satellite. The planning horizon is not long, i.e., it is usually shorter than one orbit period. A binary decision variable and the imaging order are used as the design variables, and the total observation revenue combined with the influence of the total attitude maneuvering time is regarded as the optimization objective. Based on the constraints of the observation time windows, satellite attitude adjustment time, and satellite maneuverability, a constraint satisfaction mission planning model is established for ground object staring imaging by a single video satellite. Further, a modified ant colony optimization algorithm with tabu lists (Tabu-ACO) is designed to solve this problem. The proposed algorithm can fully exploit the intelligence and local search ability of ACO. Based on full consideration of the mission characteristics, the design of the tabu lists can reduce the search range of ACO and improve the algorithm efficiency significantly. The simulation results show that the proposed algorithm outperforms the conventional algorithm in terms of optimization performance, and it can obtain satisfactory scheduling results for the mission planning problem.

International Aerospace and Ground Conference on Lightning and Static Electricity (8th): Lightning Technology Roundup, held at Fort Worth, Texas on 21-23 June 1983.

DTIC Science & Technology

1983-06-01

fighter aircraft. The entire test bed is from testing of a representative digital supported above the ground plane by non - control system(s)l e.g... control and Increased systems Integration a. Raw data must be collected and Introduce new requirements for protection, experimental setups and An accurate...presented, several possible solutions to the grounding prob! - are suggested. All rely on establishing initial ground contact through a controlled non -zero

European questions related to satelite power systems

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

Kassing, D.

1983-01-01

A number of problems which have been identified in recent European studies related to satellite power systems are addressed. Based on energy demand and supply projections for Europe, developed by the International Institute for Applied Systems Analysis, the potential of power satellites in a future energy mix is discussed. A few major constraints are presented which may restrict power transmission to European receiving sites, e.g., orbital limitations, siting problems of the ground station, and economic and institutional issues. Conceptual designs for the structure of ground receiving stations located offshore near the European coastlines are described.

Shorter unentangled proofs for ground state connectivity

NASA Astrophysics Data System (ADS)

Caha, Libor; Nagaj, Daniel; Schwarz, Martin

2018-07-01

Can one considerably shorten a proof for a quantum problem by using a protocol with a constant number of unentangled provers? We consider a frustration-free variant of the sf {QCMA}-complete ground state connectivity (GSCON) problem for a system of size n with a proof of superlinear size. We show that we can shorten this proof in sf {QMA}(2): There exists a two-copy, unentangled proof with length of order n, up to logarithmic factors, while the completeness-soundness gap of the new protocol becomes a small inverse polynomial in n.

Survival of the relocated population of the U. S. after a nuclear attack. Final report

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

Haaland, C.M.; Chester, C.V.; Wigner, E.P.

1976-06-01

The feasibility of continued survival after a hypothetical nuclear attack is evaluated for people relocated from high-risk areas during the crisis period before the attack. The attack consists of 6559 MT, of which 5951 MT are ground bursts on military, industrial, and urban targets. Relocated people are assumed to be adequately protected from fallout radiation by shelters of various kinds. The major problems in the postattack situation will be the control of exposure to fallout radiation, and prevention of severe food shortages to several tens of millions of people.

Pore Formation and Mobility Investigation video images

NASA Technical Reports Server (NTRS)

2003-01-01

Video images sent to the ground allow scientists to watch the behavior of the bubbles as they control the melting and freezing of the material during the Pore Formation and Mobility Investigation (PFMI) in the Microgravity Science Glovebox aboard the International Space Station. While the investigation studies the way that metals behave at the microscopic scale on Earth -- and how voids form -- the experiment uses a transparent material called succinonitrile that behaves like a metal to study this problem. The bubbles do not float to the top of the material in microgravity, so they can study their interactions.

Optical sensors in water monitoring

NASA Astrophysics Data System (ADS)

Gauglitz, Guenter

2007-07-01

An upcoming problem in Europe is the protection of water resources and control of water quality. Coastal areas, rivers, ground water, wetlands, and especially drinking water require permanent monitoring to avoid pollution by small organic molecules or especially endocrine disrupting compounds. Biosensors have demonstrated the proof-of-principle of immunochemistry for these applications. It turns out that especially optical methods based on fluorescence detection can be successfully used for the development of fast, sensitive, cost-effective, and easy-to-use analytical systems meeting the requirements given by European Community Directives and national legislation. Results obtained with the RIANA and AWACSS systems are discussed here.

Air-ground information transfer in the National Airspace System

NASA Technical Reports Server (NTRS)

Lee, Alfred T.; Lozito, Sandra

1989-01-01

This paper reviews NASA's Aviation Safety Reporting System incident data for a two-year period in order to identify the frequency of air-ground information transfer errors and the factors associated with their occurrence. Of the more than 14,000 primary reports received during the 1985 and 1986 reporting period, one out of four reports concerned problems of information transfer between aircraft and ATC. Approximately half of these errors were associated directly or indirectly with aircraft deviations from assigned heading or altitude. The majority of incidents cited some human-system problem such as workload, cockpit distractions, etc., as the primary contributing factor. Improvements in air-ground information transfer using existing and future (e.g., data link) technology are proposed centering on the development and application of user-centered information management principles.

MODELING MULTIPHASE ORGANIC CHEMICAL TRANSPORT IN SOILS AND GROUND WATER

EPA Science Inventory

Subsurface contamination due to immiscible organic liquids is a widespread problem which poses a serious threat to ground-water resources. n order to understand the movement of such materials in the subsurface, a mathematical model was developed for multiphase flow and multicompo...

FIELD STUDY OF ARSENIC REMOVAL FROM GROUNDWATER BY ZEROVALENT IRON

EPA Science Inventory

Contamination of ground-water resources by arsenic is a widespread environmental problem; consequently, there is a need for developments and improvements of remedial technologies to effectively manage arsenic contamination in ground water and soils. In June 2005, a 7 m long, 14 ...

Vector control in developed countries

PubMed Central

Peters, Richard F.

1963-01-01

The recent rapid growth of California's population, leading to competition for space between residential, industrial and agricultural interests, the development of its water resources and increasing water pollution provide the basic ingredients of its present vector problems. Within the past half-century, the original mosquito habitats provided by nature have gradually given place to even more numerous and productive habitats of man-made character. At the same time, emphasis in mosquito control has shifted from physical to chemical, with the more recent extension to biological approaches as well. The growing domestic fly problem, continuing despite the virtual disappearance of the horse, is attributable to an increasing amount of organic by-products, stemming from growing communities, expanding industries and changing agriculture. The programme for the control of disease vectors and pest insects and animals directs its major effort to the following broad areas: (1) water management (including land preparation), (2) solid organic wastes management (emphasizing utilization), (3) community management (including design, layout, and storage practices of buildings and grounds), and (4) recreational area management (related to wildlife management). It is apparent that vector control can often employ economics as an ally in securing its objectives. Effective organization of the environment to produce maximum economic benefits to industry, agriculture, and the community results generally in conditions unfavourable to the survival of vector and noxious animal species. Hence, vector prevention or suppression is preferable to control as a programme objective. PMID:20604166

An Analysis of Tower (Ground) Controller - Pilot Voice Communications

DOT National Transportation Integrated Search

1995-11-01

This report is based on an analysis of over 48 hours of pilot-controller communications recorded from the ground-control : frequency at twelve air traffic control towers. The analysis examined the complexity of controller instructions, that : is, how...

Operationally Efficient Propulsion System Study (OEPSS) data book. Volume 1: Generic ground operations data

NASA Technical Reports Server (NTRS)

Byrd, Raymond J.

1990-01-01

This study was initiated to identify operations problems and cost drivers for current propulsion systems and to identify technology and design approaches to increase the operational efficiency and reduce operations costs for future propulsion systems. To provide readily usable data for the Advance Launch System (ALS) program, the results of the Operationally Efficient Propulsion System Study (OEPSS) were organized into a series of OEPSS Data Books as follows: Volume 1, Generic Ground Operations Data; Volume 2, Ground Operations Problems; Volume 3, Operations Technology; Volume 4, OEPSS Design Concepts; and Volume 5, OEPSS Final Review Briefing, which summarizes the activities and results of the study. This volume presents ground processing data for a generic LOX/LH2 booster and core propulsion system based on current STS experience. The data presented includes: top logic diagram, process flow, activities bar-chart, loaded timelines, manpower requirements in terms of duration, headcount and skill mix per operations and maintenance instruction (OMI), and critical path tasks and durations.

Definition of ground test for Large Space Structure (LSS) control verification

NASA Technical Reports Server (NTRS)

Waites, H. B.; Doane, G. B., III; Tollison, D. K.

1984-01-01

An overview for the definition of a ground test for the verification of Large Space Structure (LSS) control is given. The definition contains information on the description of the LSS ground verification experiment, the project management scheme, the design, development, fabrication and checkout of the subsystems, the systems engineering and integration, the hardware subsystems, the software, and a summary which includes future LSS ground test plans. Upon completion of these items, NASA/Marshall Space Flight Center will have an LSS ground test facility which will provide sufficient data on dynamics and control verification of LSS so that LSS flight system operations can be reasonably ensured.

Shuttle avionics software trials, tribulations and success

NASA Technical Reports Server (NTRS)

Henderson, O. L.

1985-01-01

The early problems and the solutions developed to provide the required quality software needed to support the space shuttle engine development program are described. The decision to use a programmable digital control system on the space shuttle engine was primarily based upon the need for a flexible control system capable of supporting the total engine mission on a large complex pump fed engine. The mission definition included all control phases from ground checkout through post shutdown propellant dumping. The flexibility of the controller through reprogrammable software allowed the system to respond to the technical challenges and innovation required to develop both the engine and controller hardware. This same flexibility, however, placed a severe strain on the capability of the software development and verification organization. The overall development program required that the software facility accommodate significant growth in both the software requirements and the number of software packages delivered. This challenge was met by reorganization and evolution in the process of developing and verifying software.

Study on Performance of Integration Control by Man and Machine in Stage of Final Approaching for Spaceship Rendezvous and Docking

NASA Astrophysics Data System (ADS)

Zhou, Qianxiang; Liu, Zhongqi

With the development of manned space technology, space rendezvous and docking (RVD) technology will play a more and more important role. The astronauts’ participation in a final close period of man-machine combination control is an important way of RVD technology. Spacecraft RVD control involves control problem of a total of 12 degrees of freedom (location) and attitude which it relative to the inertial space the orbit. Therefore, in order to reduce the astronauts’ operation load and reduce the security requirements to the ground station and achieve an optimal performance of the whole man-machine system, it is need to study how to design the number of control parameters of astronaut or aircraft automatic control system. In this study, with the laboratory conditions on the ground, a method was put forward to develop an experimental system in which the performance evaluation of spaceship RVD integration control by man and machine could be completed. After the RVD precision requirements were determined, 26 male volunteers aged 20-40 took part in the performance evaluation experiments. The RVD integration control success rates and total thruster ignition time were chosen as evaluation indices. Results show that if less than three RVD parameters control tasks were finished by subject and the rest of parameters control task completed by automation, the RVD success rate would be larger than eighty-eight percent and the fuel consumption would be optimized. In addition, there were two subjects who finished the whole six RVD parameters control tasks by enough train. In conclusion, if the astronauts' role should be integrated into the RVD control, it was suitable for them to finish the heading, pitch and roll control in order to assure the man-machine system high performance. If astronauts were needed to finish all parameter control, two points should be taken into consideration, one was enough fuel and another was enough long operation time.

Prediction of forces and moments for flight vehicle control effectors. Part 2: An analysis of delta wing aerodynamic control effectiveness in ground effect

NASA Technical Reports Server (NTRS)

Maughmer, Mark D.; Ozoroski, L.; Ozoroski, T.; Straussfogel, D.

1990-01-01

Many types of hypersonic aircraft configurations are currently being studied for feasibility of future development. Since the control of the hypersonic configurations throughout the speed range has a major impact on acceptable designs, it must be considered in the conceptual design stage. Here, an investigation of the aerodynamic control effectiveness of highly swept delta planforms operating in ground effect is presented. A vortex-lattice computer program incorporating a free wake is developed as a tool to calculate aerodynamic stability and control derivatives. Data generated using this program are compared to experimental data and to data from other vortex-lattice programs. Results show that an elevon deflection produces greater increments in C sub L and C sub M in ground effect than the same deflection produces out of ground effect and that the free wake is indeed necessary for good predictions near the ground.

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.

Collaboration Between NASA Centers of Excellence on Autonomous System Software Development

NASA Technical Reports Server (NTRS)

Goodrich, Charles H.; Larson, William E.; Delgado, H. (Technical Monitor)

2001-01-01

Software for space systems flight operations has its roots in the early days of the space program when computer systems were incapable of supporting highly complex and flexible control logic. Control systems relied on fast data acquisition and supervisory control from a roomful of systems engineers on the ground. Even though computer hardware and software has become many orders of magnitude more capable, space systems have largely adhered to this original paradigm In an effort to break this mold, Kennedy Space Center (KSC) has invested in the development of model-based diagnosis and control applications for ten years having broad experience in both ground and spacecraft systems and software. KSC has now partnered with Ames Research Center (ARC), NASA's Center of Excellence in Information Technology, to create a new paradigm for the control of dynamic space systems. ARC has developed model-based diagnosis and intelligent planning software that enables spacecraft to handle most routine problems automatically and allocate resources in a flexible way to realize mission objectives. ARC demonstrated the utility of onboard diagnosis and planning with an experiment aboard Deep Space I in 1999. This paper highlights the software control system collaboration between KSC and ARC. KSC has developed a Mars In-situ Resource Utilization testbed based on the Reverse Water Gas Shift (RWGS) reaction. This plant, built in KSC's Applied Chemistry Laboratory, is capable of producing the large amount of Oxygen that would be needed to support a Human Mars Mission. KSC and ARC are cooperating to develop an autonomous, fault-tolerant control system for RWGS to meet the need for autonomy on deep space missions. The paper will also describe how the new system software paradigm will be applied to Vehicle Health Monitoring, tested on the new X vehicles and integrated into future launch processing systems.

Path planning and Ground Control Station simulator for UAV

NASA Astrophysics Data System (ADS)

Ajami, A.; Balmat, J.; Gauthier, J.-P.; Maillot, T.

In this paper we present a Universal and Interoperable Ground Control Station (UIGCS) simulator for fixed and rotary wing Unmanned Aerial Vehicles (UAVs), and all types of payloads. One of the major constraints is to operate and manage multiple legacy and future UAVs, taking into account the compliance with NATO Combined/Joint Services Operational Environment (STANAG 4586). Another purpose of the station is to assign the UAV a certain degree of autonomy, via autonomous planification/replanification strategies. The paper is organized as follows. In Section 2, we describe the non-linear models of the fixed and rotary wing UAVs that we use in the simulator. In Section 3, we describe the simulator architecture, which is based upon interacting modules programmed independently. This simulator is linked with an open source flight simulator, to simulate the video flow and the moving target in 3D. To conclude this part, we tackle briefly the problem of the Matlab/Simulink software connection (used to model the UAV's dynamic) with the simulation of the virtual environment. Section 5 deals with the control module of a flight path of the UAV. The control system is divided into four distinct hierarchical layers: flight path, navigation controller, autopilot and flight control surfaces controller. In the Section 6, we focus on the trajectory planification/replanification question for fixed wing UAV. Indeed, one of the goals of this work is to increase the autonomy of the UAV. We propose two types of algorithms, based upon 1) the methods of the tangent and 2) an original Lyapunov-type method. These algorithms allow either to join a fixed pattern or to track a moving target. Finally, Section 7 presents simulation results obtained on our simulator, concerning a rather complicated scenario of mission.

Optimising UAV topographic surveys processed with structure-from-motion: Ground control quality, quantity and bundle adjustment

NASA Astrophysics Data System (ADS)

James, Mike R.; Robson, Stuart; d'Oleire-Oltmanns, Sebastian; Niethammer, Uwe

2016-04-01

Structure-from-motion (SfM) algorithms are greatly facilitating the production of detailed topographic models based on images collected by unmanned aerial vehicles (UAVs). However, SfM-based software does not generally provide the rigorous photogrammetric analysis required to fully understand survey quality. Consequently, error related to problems in control point data or the distribution of control points can remain undiscovered. Even if these errors are not large in magnitude, they can be systematic, and thus have strong implications for the use of products such as digital elevation models (DEMs) and orthophotos. Here, we develop a Monte Carlo approach to (1) improve the accuracy of products when SfM-based processing is used and (2) reduce the associated field effort by identifying suitable lower density deployments of ground control points. The method highlights over-parameterisation during camera self-calibration and provides enhanced insight into control point performance when rigorous error metrics are not available. Processing was implemented using commonly-used SfM-based software (Agisoft PhotoScan), which we augment with semi-automated and automated GCPs image measurement. We apply the Monte Carlo method to two contrasting case studies - an erosion gully survey (Taurodont, Morocco) carried out with an fixed-wing UAV, and an active landslide survey (Super-Sauze, France), acquired using a manually controlled quadcopter. The results highlight the differences in the control requirements for the two sites, and we explore the implications for future surveys. We illustrate DEM sensitivity to critical processing parameters and show how the use of appropriate parameter values increases DEM repeatability and reduces the spatial variability of error due to processing artefacts.

High performance VLSI telemetry data systems

NASA Technical Reports Server (NTRS)

Chesney, J.; Speciale, N.; Horner, W.; Sabia, S.

1990-01-01

NASA's deployment of major space complexes such as Space Station Freedom (SSF) and the Earth Observing System (EOS) will demand increased functionality and performance from ground based telemetry acquisition systems well above current system capabilities. Adaptation of space telemetry data transport and processing standards such as those specified by the Consultative Committee for Space Data Systems (CCSDS) standards and those required for commercial ground distribution of telemetry data, will drive these functional and performance requirements. In addition, budget limitations will force the requirement for higher modularity, flexibility, and interchangeability at lower cost in new ground telemetry data system elements. At NASA's Goddard Space Flight Center (GSFC), the design and development of generic ground telemetry data system elements, over the last five years, has resulted in significant solutions to these problems. This solution, referred to as the functional components approach includes both hardware and software components ready for end user application. The hardware functional components consist of modern data flow architectures utilizing Application Specific Integrated Circuits (ASIC's) developed specifically to support NASA's telemetry data systems needs and designed to meet a range of data rate requirements up to 300 Mbps. Real-time operating system software components support both embedded local software intelligence, and overall system control, status, processing, and interface requirements. These components, hardware and software, form the superstructure upon which project specific elements are added to complete a telemetry ground data system installation. This paper describes the functional components approach, some specific component examples, and a project example of the evolution from VLSI component, to basic board level functional component, to integrated telemetry data system.

Ground reaction force comparison of controlled resistance methods to isoinertial loading of the squat exercise - biomed 2010.

PubMed

Paulus, David C; Reynolds, Michael C; Schilling, Brian K

2010-01-01

The ground reaction force during the concentric (raising) portion of the squat exercise was compared to that of isoinertial loading (free weights) for three pneumatically controlled resistance methods: constant resistance, cam force profile, and proportional force control based on velocity. Constant force control showed lower ground reaction forces than isoinertial loading throughout the range of motion (ROM). The cam force profile exhibited slightly greater ground reaction forces than isoinertial loading at 10 and 40% ROM with fifty-percent greater loading at 70% ROM. The proportional force control consistently elicited greater ground reaction force than isoinertial loading, which progressively ranged from twenty to forty percent increase over isoinertial loading except for being approximately equal at 85% ROM. Based on these preliminary results, the proportional control shows the most promise for providing loading that is comparable in magnitude to isoinertial loading. This technology could optimize resistance exercise for sport-specific training or as a countermeasure to atrophy during spaceflight.

A ground based phase control system for the solar power satellite, volume 4

NASA Technical Reports Server (NTRS)

Chie, C. M.

1980-01-01

A ground phase control system is studied as an alternative approach to the current reference retrodirective phase control system in order to simplify the spaceborne hardware requirement. Based on waveform selections, functional subsystems to implement the ground-based phase control concept are identified and functionally represented. It was concluded that the feasibility of the concept becomes unclear if the conditions of the ionosphere and satellite motion are not met.

ANALYTIC ELEMENT GROUND WATER MODELING AS A RESEARCH PROGRAM (1980-2006)

EPA Science Inventory

Scientists and engineers who use the analytic element method (AEM) for solving problems of regional ground water flow may be considered a community, and this community can be studied from the perspective of history and philosophy of science. Applying the methods of the Hungarian...

An Investigation of the Effects of the Time Lag due to Long Transmission Distances Upon Remote Control. Phase 1; Tracking Experiments

NASA Technical Reports Server (NTRS)

Adams, James L.

1961-01-01

A series of pursuit tracking tasks were performed incorporating a transport lag in the control loop. The target was a mixture of four sine waves, the fastest having a frequency of 16 cycles per minute at full speed. An attempt was made to design the experiments so that they would provide data applicable to remote control of a ground vehicle over long transmission distances. Three programs were run. In each the time lag was placed between the control and the display. In the first program a velocity control was used and the operator was told that his knob controlled a vehicle, the problem represented a road 9 and he was to drive his vehicle along the road 9 using the delayed vehicle position as feedback for whatever means he desired. The objective was not to match the display traces. In the second program a velocity control was used, and the operator was told that the problem trace represented a road and the delayed trace represented a vehicle and he was to keep them together. The objective was to match display traces. The third program was identical with the first, except that an acceleration control was used rather than a velocity control. Target speeds used were full speed, 1/2 speed, 1/4 speed, 1/8 speed, and 1/16 speed. Time lags were 1/4 second, l/2 second, 1 second, 1-1/2 second, 2 second, 3 second, and 6 seconds. The experimental results are presented in the last section of this report.

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.

The High Altitude Pollution Program (1976-1982).

DTIC Science & Technology

1984-01-01

ground, where air pollution problems arise due to ground level emissions from, for example, automobiles and power plants) to about 25 km above the...downward and poleward. Near the ground, in areas such as cities prone to air pollution , ozone is produced by nitrogen dioxide photolysis and reaction...Spectrophotcmeter Total Ozone Measurement Errors caused by Interfering Absorbing Species Such as SO2, NO2 and Photochemically Produced 03 IN Polluted Air ," NOAA

The pit and the pendulum: the impact on teen smokers of including a designated smoking area in school tobacco control policy.

PubMed

Baillie, L E; Lovato, C Y; Taylor, E; Rutherford, M B; Smith, M

2008-12-01

Thirty per cent of school districts in British Columbia do not ban smoking outright on school grounds, and in several instances, smoking is permitted in smoking pits, regardless of school district policy. While there is evidence to suggest that enforcing a tobacco-free environment for students does reduce adolescent smoking rates, the concomitant safety and discipline problems it creates for school staff and administration are demanding and complex, and may override concerns regarding student smoking. This study uses a qualitative approach to explore the meanings that students place on tobacco control policy and the impact that these meanings have on their own smoking behaviours. We found that students were surprised and concerned that smoking was permitted on school property and that it negatively impacted their own tobacco prevention/control/cessation attempts.

Comparison ofdvanced turboprop interior noise control ground and flight test data

NASA Technical Reports Server (NTRS)

Simpson, Myles A.; Tran, Boi N.

1992-01-01

Interior noise ground tests conducted on a DC-9 aircraft test section are described. The objectives were to study ground test and analysis techniques for evaluating the effectiveness of interior noise control treatments for advanced turboprop aircraft, and to study the sensitivity of the ground test results to changes in various test conditions. Noise and vibration measurements were conducted under simulated advanced turboprop excitation, for two interior noise control treatment configurations. These ground measurement results were compared with results of earlier UHB (Ultra High Bypass) Demonstrator flight sts with comparable interior treatment configurations. The Demonstrator is an MD-80 test aircraft with the left JT8D engine replaced with a prototype UHB advanced turboprop engine.

Comparison ofdvanced turboprop interior noise control ground and flight test data

NASA Astrophysics Data System (ADS)

Simpson, Myles A.; Tran, Boi N.

Interior noise ground tests conducted on a DC-9 aircraft test section are described. The objectives were to study ground test and analysis techniques for evaluating the effectiveness of interior noise control treatments for advanced turboprop aircraft, and to study the sensitivity of the ground test results to changes in various test conditions. Noise and vibration measurements were conducted under simulated advanced turboprop excitation, for two interior noise control treatment configurations. These ground measurement results were compared with results of earlier UHB (Ultra High Bypass) Demonstrator flight sts with comparable interior treatment configurations. The Demonstrator is an MD-80 test aircraft with the left JT8D engine replaced with a prototype UHB advanced turboprop engine.

Electron microscopic analysis of gravisensing Chara rhizoids developed under microgravity conditions.

PubMed

Braun, M; Buchen, B; Sievers, A

1999-01-01

Tip-growing, unicellular Chara rhizoids that react gravitropically on Earth developed in microgravity. In microgravity, they grew out from the nodes of the green thallus in random orientation. Development and morphogenesis followed an endogenous program that is not affected by the gravitational field. The cell shape, the polar cytoplasmic organization, and the polar distribution of cell organelles, except for the statoliths, were not different from controls that had grown on earth (ground controls). The ultrastructure of the organelles and the microtubules were well preserved. Microtubules were excluded from the apical zone in both ground controls as well as microgravity-grown rhizoids. The statoliths (vesicles containing BaSO4 crystals in a matrix) in microgravity-grown rhizoids were spread over a larger area (up to 50 microm basal to the tip) than the statoliths of ground controls (10-30 microm). Some statoliths were even located in the subapical zone close to microtubules, which was not observed in ground controls. The crystals in statoliths from microgravity-grown rhizoids appeared more loosely arranged in the vesicle matrix compared with ground controls. The chemical composition of the crystals was identified as BaSO4 by X-ray microanalysis. There is evidence that the amount of BaSO4 in statoliths of rhizoids developed in microgravity is lower than in ground controls, indicating that the gravisensitivity of microgravity-developed rhizoids might be reduced compared with ground controls. Lack of gravity, however, does not affect the process of tip growth and does not inhibit the development of the structures needed for the gravity-sensing machinery.

NITRATE CONTAMINATION OF GROUND WATER FROM LAND APPLICATION OF SWINE WASTE: CASE STUDY AND GENERAL CONSIDERATIONS

EPA Science Inventory

Guidelines for land application of CAFO waste may not be sufficient to prevent ground water contamination by nitrate. A case study is presented illustrating the problem for one field site disposing of swine waste. Data are discussed in context with documented land application ...

Students Build Mathematical Theory: Semantic Warrants in Argumentation

ERIC Educational Resources Information Center

Walter, Janet G.; Barros, Tara

2011-01-01

In this paper, we explore the development of two grounded theories. One theory is mathematical and grounded in the work of university calculus students' collaborative development of mathematical methods for finding the volume of a solid of revolution, in response to mathematical necessity in problem solving, without prior instruction on solution…

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…

Ground Water in a Fish Tank.

ERIC Educational Resources Information Center

Mayshark, Robin K.

1992-01-01

Describes creating a Model Aquatic/Terrestrial Ecosystem for use in helping students understand how water moves beneath the ground's surface. The model is constructed from a fish tank using rocks, soil, gravel, clay, and organic materials. Author describes possible cooperative-learning and problem-solving activities that can be done with this…

Ground Water Flow No Longer A Mystery

ERIC Educational Resources Information Center

Lehr, Jay H.; Pettyjohn, Wayne A.

1976-01-01

Examined are the physical characteristics of ground water movement. Some potential pollution problems are identified. Models are used to explain mathematical and hydraulic principles of flow toward a pumping well and an effluent stream, flow around and through lenticular beds, and effects of pumping on the water table. (Author/MR)

Ground water security and drought in Africa: linking availability, access, and demand.

PubMed

Calow, Roger C; Macdonald, Alan M; Nicol, Alan L; Robins, Nick S

2010-01-01

Drought in Africa has been extensively researched, particularly from meteorological, agricultural, and food security perspectives. However, the impact of drought on water security, particularly ground water dependent rural water supplies, has received much less attention. Policy responses have concentrated on food needs, and it has often been difficult to mobilize resources for water interventions, despite evidence that access to safe water is a serious and interrelated concern. Studies carried out in Ghana, Malawi, South Africa, and Ethiopia highlight how rural livelihoods are affected by seasonal stress and longer-term drought. Declining access to food and water is a common and interrelated problem. Although ground water plays a vital role in buffering the effects of rainfall variability, water shortages and difficulties in accessing water that is available can affect domestic and productive water uses, with knock-on effects on food consumption and production. Total depletion of available ground water resources is rarely the main concern. A more common scenario is a spiral of water insecurity as shallow water sources fail, additional demands are put on remaining sources, and mechanical failures increase. These problems can be planned for within normal development programs. Water security mapping can help identify vulnerable areas, and changes to monitoring systems can ensure early detection of problems. Above all, increasing the coverage of ground water-based rural water supplies, and ensuring that the design and siting of water points is informed by an understanding of hydrogeological conditions and user demand, can significantly increase the resilience of rural communities to climate variability.

A Self-Tuning Kalman Filter for Autonomous Spacecraft Navigation

NASA Technical Reports Server (NTRS)

Truong, Son H.

1998-01-01

Most navigation systems currently operated by NASA are ground-based, and require extensive support to produce accurate results. Recently developed systems that use Kalman Filter and Global Positioning System (GPS) data for orbit determination greatly reduce dependency on ground support, and have potential to provide significant economies for NASA spacecraft navigation. Current techniques of Kalman filtering, however, still rely on manual tuning from analysts, and cannot help in optimizing autonomy without compromising accuracy and performance. This paper presents an approach to produce a high accuracy autonomous navigation system fully integrated with the flight system. The resulting system performs real-time state estimation by using an Extended Kalman Filter (EKF) implemented with high-fidelity state dynamics model, as does the GPS Enhanced Orbit Determination Experiment (GEODE) system developed by the NASA Goddard Space Flight Center. Augmented to the EKF is a sophisticated neural-fuzzy system, which combines the explicit knowledge representation of fuzzy logic with the learning power of neural networks. The fuzzy-neural system performs most of the self-tuning capability and helps the navigation system recover from estimation errors. The core requirement is a method of state estimation that handles uncertainties robustly, capable of identifying estimation problems, flexible enough to make decisions and adjustments to recover from these problems, and compact enough to run on flight hardware. The resulting system can be extended to support geosynchronous spacecraft and high-eccentricity orbits. Mathematical methodology, systems and operations concepts, and implementation of a system prototype are presented in this paper. Results from the use of the prototype to evaluate optimal control algorithms implemented are discussed. Test data and major control issues (e.g., how to define specific roles for fuzzy logic to support the self-learning capability) are also discussed. In addition, architecture of a complete end-to-end candidate flight system that provides navigation with highly autonomous control using data from GPS is presented.

Bioremediation of petroleum hydrocarbon-contaminated ground water: The perspectives of history and hydrology

USGS Publications Warehouse

Chapelle, F.H.

1999-01-01

Bioremediation, the use of microbial degradation processes to detoxify environmental contamination, was first applied to petroleum hydrocarbon-contaminated ground water systems in the early 1970s. Since that time, these technologies have evolved in some ways that were clearly anticipated early investigators, and in other ways that were not foreseen. The expectation that adding oxidants and nutrients to contaminated aquifers would enhance biodegradation, for example, has been born out subsequent experience. Many of the technologies now in common use such as air sparging, hydrogen peroxide addition, nitrate addition, and bioslurping, are conceptually similar to the first bioremediation systems put into operation. More unexpected, however, were the considerable technical problems associated with delivering oxidants and nutrients to heterogeneous ground water systems. Experience has shown that the success of engineered bioremediation systems depends largely on how effectively directions and rates of ground water flow can be controlled, and thus how efficiently oxidants and nutrients can be delivered to contaminated aquifer sediments. The early expectation that injecting laboratory-selected or genetically engineered cultures of hydrocarbon-degrading bacteria into aquifers would be a useful bioremediation technology has not been born out subsequent experience. Rather, it appears that petroleum hydrocarbon-degrading bacteria are ubiquitous in ground water systems and that bacterial addition is usually unnecessary. Perhaps the technology that was least anticipated early investigators was the development of intrinsic bioremediation. Experience has shown that natural attenuation mechanisms - biodegradation, dilution, and sorption - limit the migration of contaminants to some degree in all ground water systems. Intrinsic bioremediation is the deliberate use of natural attenuation processes to treat contaminated ground water to specified concentration levels at predetermined points in the aquifer. In current practice, intrinsic bioremediation of petroleum hydrocarbons requires a systematic assessment to show that ambient natural attenuation mechanisms are efficient enough to meet regulatory requirements and a monitoring program to verify that performance requirements are met in the future.

Modeling the Sliding/Falling Ladder Paradox

ERIC Educational Resources Information Center

Fox, William P.; Fox, James B.

2003-01-01

Recently we were presented with an interesting twist to the sliding ladder problem viewed in the related rates section of most calculus textbooks. Our problem concerning a sliding ladder that eventually hits the ground. At first, those attempting this problem fell into the calculus trap using only related rates. Previous work for this problem…

The Psychology of Human Performance.

ERIC Educational Resources Information Center

Thomas, David A.

This paper offers a theoretically grounded template for analyzing the root causes of individual performance problems in school, work, or personal pursuits. There are four basic reasons why individuals fail to perform as desired: they don't know what to do (communication problem); they don't know how to do it (knowledge problem); they don't want to…

Defining the Problem of Practice Dissertation: Where's the Practice, What's the Problem?

ERIC Educational Resources Information Center

Belzer, Alisa; Ryan, Sharon

2013-01-01

This article describes the evolution of the conceptualization of the "problem of practice" dissertation in the new EdD Program at the Graduate School of Education at Rutgers, the State University of New Jersey. Our definition and conceptualization of the professional practice dissertation is grounded in a review of relevant literature…

Addict Life Stories: An Exploration of the Methodological Grounds for the Study of Social Problems.

ERIC Educational Resources Information Center

Kaplan, Charles D.

1982-01-01

Explores the use of sociological life histories to study social problems such as drug addiction. The factors influencing the fluctuating popularity of this research technique within the social sciences are examined. The impact of the researcher's direct exposure to the interviewee's problems on research results is discussed. (AM)

Contamination concerns in the modular containerless processing facility

NASA Technical Reports Server (NTRS)

Seshan, P. K.; Trinh, E. H.

1989-01-01

This paper describes the problems of the control and management of contamination in the Modular Containerless Processing Facility (MCPF), that is being currently developed at the JPL for the Space Station, and in the MCPF's precursor version, called the Drop Physics Module (DPM), which will be carried aboard one or more Space Shuttle missions. Attention is given to the identification of contamination sources, their mode of transport to the sample positioned within the chamber, and the protection of the sample, as well as to the mathematical simulatiom of the contaminant transport. It is emphasized that, in order to choose and implement the most appropriate contamination control strategy for each investigator, a number of simplified mathematical simulations will have to be developed, and ground-based contamination experiments will have to be carried out with identical materials.

Effectiveness of a Standardized Equine-Assisted Therapy Program for Children with Autism Spectrum Disorder.

PubMed

Borgi, Marta; Loliva, Dafne; Cerino, Stefania; Chiarotti, Flavia; Venerosi, Aldina; Bramini, Maria; Nonnis, Enrico; Marcelli, Marco; Vinti, Claudia; De Santis, Chiara; Bisacco, Francesca; Fagerlie, Monica; Frascarelli, Massimo; Cirulli, Francesca

2016-01-01

In this study the effectiveness of an equine-assisted therapy (EAT) in improving adaptive and executive functioning in children with autism spectrum disorder (ASD) was examined (children attending EAT, n = 15, control group n = 13; inclusion criteria: IQ > 70). Therapeutic sessions consisted in structured activities involving horses and included both work on the ground and riding. Results indicate an improvement in social functioning in the group attending EAT (compared to the control group) and a milder effect on motor abilities. Improved executive functioning was also observed (i.e. reduced planning time in a problem-solving task) at the end of the EAT program. Our findings provide further support for the use of animal-assisted intervention programs as complementary intervention strategies for children with ASD.

A Neural Dynamic Model Generates Descriptions of Object-Oriented Actions.

PubMed

Richter, Mathis; Lins, Jonas; Schöner, Gregor

2017-01-01

Describing actions entails that relations between objects are discovered. A pervasively neural account of this process requires that fundamental problems are solved: the neural pointer problem, the binding problem, and the problem of generating discrete processing steps from time-continuous neural processes. We present a prototypical solution to these problems in a neural dynamic model that comprises dynamic neural fields holding representations close to sensorimotor surfaces as well as dynamic neural nodes holding discrete, language-like representations. Making the connection between these two types of representations enables the model to describe actions as well as to perceptually ground movement phrases-all based on real visual input. We demonstrate how the dynamic neural processes autonomously generate the processing steps required to describe or ground object-oriented actions. By solving the fundamental problems of neural pointing, binding, and emergent discrete processing, the model may be a first but critical step toward a systematic neural processing account of higher cognition. Copyright © 2017 The Authors. Topics in Cognitive Science published by Wiley Periodicals, Inc. on behalf of Cognitive Science Society.

Kinematic primitives for walking and trotting gaits of a quadruped robot with compliant legs.

PubMed

Spröwitz, Alexander T; Ajallooeian, Mostafa; Tuleu, Alexandre; Ijspeert, Auke Jan

2014-01-01

In this work we research the role of body dynamics in the complexity of kinematic patterns in a quadruped robot with compliant legs. Two gait patterns, lateral sequence walk and trot, along with leg length control patterns of different complexity were implemented in a modular, feed-forward locomotion controller. The controller was tested on a small, quadruped robot with compliant, segmented leg design, and led to self-stable and self-stabilizing robot locomotion. In-air stepping and on-ground locomotion leg kinematics were recorded, and the number and shapes of motion primitives accounting for 95% of the variance of kinematic leg data were extracted. This revealed that kinematic patterns resulting from feed-forward control had a lower complexity (in-air stepping, 2-3 primitives) than kinematic patterns from on-ground locomotion (νm4 primitives), although both experiments applied identical motor patterns. The complexity of on-ground kinematic patterns had increased, through ground contact and mechanical entrainment. The complexity of observed kinematic on-ground data matches those reported from level-ground locomotion data of legged animals. Results indicate that a very low complexity of modular, rhythmic, feed-forward motor control is sufficient for level-ground locomotion in combination with passive compliant legged hardware.

Kinematic primitives for walking and trotting gaits of a quadruped robot with compliant legs

PubMed Central

Spröwitz, Alexander T.; Ajallooeian, Mostafa; Tuleu, Alexandre; Ijspeert, Auke Jan

2014-01-01

In this work we research the role of body dynamics in the complexity of kinematic patterns in a quadruped robot with compliant legs. Two gait patterns, lateral sequence walk and trot, along with leg length control patterns of different complexity were implemented in a modular, feed-forward locomotion controller. The controller was tested on a small, quadruped robot with compliant, segmented leg design, and led to self-stable and self-stabilizing robot locomotion. In-air stepping and on-ground locomotion leg kinematics were recorded, and the number and shapes of motion primitives accounting for 95% of the variance of kinematic leg data were extracted. This revealed that kinematic patterns resulting from feed-forward control had a lower complexity (in-air stepping, 2–3 primitives) than kinematic patterns from on-ground locomotion (νm4 primitives), although both experiments applied identical motor patterns. The complexity of on-ground kinematic patterns had increased, through ground contact and mechanical entrainment. The complexity of observed kinematic on-ground data matches those reported from level-ground locomotion data of legged animals. Results indicate that a very low complexity of modular, rhythmic, feed-forward motor control is sufficient for level-ground locomotion in combination with passive compliant legged hardware. PMID:24639645

Cluster expansion for ground states of local Hamiltonians

NASA Astrophysics Data System (ADS)

Bastianello, Alvise; Sotiriadis, Spyros

2016-08-01

A central problem in many-body quantum physics is the determination of the ground state of a thermodynamically large physical system. We construct a cluster expansion for ground states of local Hamiltonians, which naturally incorporates physical requirements inherited by locality as conditions on its cluster amplitudes. Applying a diagrammatic technique we derive the relation of these amplitudes to thermodynamic quantities and local observables. Moreover we derive a set of functional equations that determine the cluster amplitudes for a general Hamiltonian, verify the consistency with perturbation theory and discuss non-perturbative approaches. Lastly we verify the persistence of locality features of the cluster expansion under unitary evolution with a local Hamiltonian and provide applications to out-of-equilibrium problems: a simplified proof of equilibration to the GGE and a cumulant expansion for the statistics of work, for an interacting-to-free quantum quench.

Acoustic measurements in a jet engine test facility

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

Miller, V.R.

1982-01-01

The US Air Force has had problems with aircraft engine noise generated during ground run-up. These operations have resulted in many community complaints and serious restrictions being placed on ground run-up activity which affected training and fleet readiness. A program of noise abatement was undertaken to suppress ground run-up noise. The original designs included water-cooled noise suppressors which were peculiar to a single aircraft. This made each usable only with the aircraft for which it was designed. Noise surveys indicated that the close-coupled suppressor did not address the problem of noise radiated from unenclosed portions of the fuselage. To alleviatemore » this situation, the approach adopted was to use a complete aircraft enclosure, called a hush house, and a large augmenter tube which is totally air-cooled.« less

High-order Path Integral Monte Carlo methods for solving strongly correlated fermion problems

NASA Astrophysics Data System (ADS)

Chin, Siu A.

2015-03-01

In solving for the ground state of a strongly correlated many-fermion system, the conventional second-order Path Integral Monte Carlo method is plagued with the sign problem. This is due to the large number of anti-symmetric free fermion propagators that are needed to extract the square of the ground state wave function at large imaginary time. In this work, I show that optimized fourth-order Path Integral Monte Carlo methods, which uses no more than 5 free-fermion propagators, in conjunction with the use of the Hamiltonian energy estimator, can yield accurate ground state energies for quantum dots with up to 20 polarized electrons. The correlations are directly built-in and no explicit wave functions are needed. This work is supported by the Qatar National Research Fund NPRP GRANT #5-674-1-114.

Chemical Weed Control Increases Survival and Growth in Hardwood Plantings

Treesearch

Gayne G. Erdmann

1967-01-01

In a plantation of four hardwood species on a silt loam soil planted to 1-0 stock, 4 pounds of active atrazine or simazine controlled weeds effectively without injuring the trees. Chemical weed control was better on plowed and disked ground than on unprepared ground. Yellow-poplar and white ash grew faster on prepared ground. Black walnut and red oak did not respond...

Computer-aided system for detecting runway incursions

NASA Astrophysics Data System (ADS)

Sridhar, Banavar; Chatterji, Gano B.

1994-07-01

A synthetic vision system for enhancing the pilot's ability to navigate and control the aircraft on the ground is described. The system uses the onboard airport database and images acquired by external sensors. Additional navigation information needed by the system is provided by the Inertial Navigation System and the Global Positioning System. The various functions of the system, such as image enhancement, map generation, obstacle detection, collision avoidance, guidance, etc., are identified. The available technologies, some of which were developed at NASA, that are applicable to the aircraft ground navigation problem are noted. Example images of a truck crossing the runway while the aircraft flies close to the runway centerline are described. These images are from a sequence of images acquired during one of the several flight experiments conducted by NASA to acquire data to be used for the development and verification of the synthetic vision concepts. These experiments provide a realistic database including video and infrared images, motion states from the Inertial Navigation System and the Global Positioning System, and camera parameters.

Scanning tunnelling spectroscopy as a probe of multi-Q magnetic states of itinerant magnets

DOE PAGES

Gastiasoro, Maria N.; Eremin, Ilya; Fernandes, Rafael M.; ...

2017-02-08

The combination of electronic correlations and Fermi surfaces with multiple nesting vectors can lead to the appearance of complex multi-Q magnetic ground states, hosting unusual states such as chiral density waves and quantum Hall insulators. Distinguishing single-Q and multi-Q magnetic phases is however a notoriously difficult experimental problem. Here we propose theoretically that the local density of states (LDOS) near a magnetic impurity, whose orientation may be controlled by an external magnetic field, can be used to map out the detailed magnetic configuration of an itinerant system and distinguish unambiguously between single-Q and multi-Q phases. We demonstrate this concept bymore » computing and contrasting the LDOS near a magnetic impurity embedded in three different magnetic ground states relevant to iron-based superconductors—one single-Q and two double-Q phases. Our results open a promising avenue to investigate the complex magnetic configurations in itinerant systems via standard scanning tunnelling spectroscopy, without requiring spin-resolved capability.« less

Radiation protection and instrumentation

NASA Technical Reports Server (NTRS)

Bailey, J. V.

1975-01-01

Radiation was found not to be an operational problem during the Apollo program. Doses received by the crewmen of Apollo missions 7 through 17 were small because no major solar-particle events occurred during those missions. One small event was detected by a radiation sensor outside the Apollo 12 spacecraft, but no increase in radiation dose to the crewmen inside the spacecraft was detected. Radiation protection for the Apollo program was focused on both the peculiarities of the natural space radiation environment and the increased prevalence of manmade radiation sources on the ground and onboard the spacecraft. Radiation-exposure risks to crewmen were assessed and balanced against mission gain to determine mission constraints. Operational radiation evaluation required specially designed radiation detection systems onboard the spacecraft in addition to the use of satellite data, solar observatory support, and other liaison. Control and management of radioactive sources and radiation-generating equipment was important in minimizing radiation exposure of ground-support personnel, researchers, and the Apollo flight and backup crewmen.

Development of a model of space station solar array

NASA Technical Reports Server (NTRS)

Bosela, Paul A.

1990-01-01

Space structures, such as the space station solar arrays, must be extremely lightweight, flexible structures. Accurate prediction of the natural frequencies and mode shapes is essential for determining the structural adequacy of components, and designing a control system. The tension preload in the blanket of photovoltaic solar collectors, and the free/free boundary conditions of a structure in space, causes serious reservations on the use of standard finite element techniques of solution. In particular, a phenomena known as grounding, or false stiffening, of the stiffness matrix occurs during rigid body rotation. The grounding phenomena is examined in detail. Numerous stiffness matrices developed by others are examined for rigid body rotation capability, and found lacking. Various techniques are used for developing new stiffness matrices from the rigorous solutions of the differential equations, including the solution of the directed force problem. A new directed force stiffness matrix developed by the author provides all the rigid body capabilities for the beam in space.

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.

The Kadison–Singer Problem in mathematics and engineering

PubMed Central

Casazza, Peter G.; Tremain, Janet Crandell

2006-01-01

We will see that the famous intractible 1959 Kadison–Singer Problem in C*-algebras is equivalent to fundamental open problems in a dozen different areas of research in mathematics and engineering. This work gives all these areas common ground on which to interact as well as explaining why each area has volumes of literature on their respective problems without a satisfactory resolution. PMID:16461465

Improving ground cover monitoring for wind erosion assessment using MODIS BRDF parameters

USDA-ARS?s Scientific Manuscript database

Measuring and monitoring controls on wind erosion can facilitate detection and prediction of soil degradation important for food security. Ground cover is widely recognised as an important factor for controlling soil erosion by wind and water. Consequently, maintaining ground cover (e.g., vegetation...

AGRICULTURAL DRAINAGE WELLS: IMPACT ON GROUND WATER

EPA Science Inventory

This document discusses agricultural drainage well practices, potential contamination problems that may occur, and possible management practices or regulatory solutions that could be used to alleviate those problems. The document has been written for use by state and Agency deci...

Hydrogeologic considerations for an interstate ground-water compact on the Madison aquifer, northern Great Plains

USGS Publications Warehouse

Konikow, Leonard F.

1978-01-01

The development of an interstate ground-water compact for the Madison aquifer in the Northern Great Plains may provide a framework to allocate equitably this large ground-water resource while avoiding possible future interstate legal conflicts. However, some technical problems will have to be resolved first. A compact designed to regulate or to allocate the available ground water will have to be written in very precise, legally acceptable definitions. The required definitions may infer a degree of measurement accuracy that cannot be technically or economically provided. Therefore, a trade off may be required between preserving natural conditions and allowing beneficial use of the ground-water resource.

Definition of boundary and initial conditions in the analysis of saturated ground-water flow systems - An introduction

USGS Publications Warehouse

Franke, O. Lehn; Reilly, Thomas E.; Bennett, Gordon D.

1987-01-01

Accurate definition of boundary and initial conditions is an essential part of conceptualizing and modeling ground-water flow systems. This report describes the properties of the seven most common boundary conditions encountered in ground-water systems and discusses major aspects of their application. It also discusses the significance and specification of initial conditions and evaluates some common errors in applying this concept to ground-water-system models. An appendix is included that discusses what the solution of a differential equation represents and how the solution relates to the boundary conditions defining the specific problem. This report considers only boundary conditions that apply to saturated ground-water systems.

Flight test experience and controlled impact of a large, four-engine, remotely piloted airplane

NASA Technical Reports Server (NTRS)

Kempel, R. W.; Horton, T. W.

1985-01-01

A controlled impact demonstration (CID) program using a large, four engine, remotely piloted transport airplane was conducted. Closed loop primary flight control was performed from a ground based cockpit and digital computer in conjunction with an up/down telemetry link. Uplink commands were received aboard the airplane and transferred through uplink interface systems to a highly modified Bendix PB-20D autopilot. Both proportional and discrete commands were generated by the ground pilot. Prior to flight tests, extensive simulation was conducted during the development of ground based digital control laws. The control laws included primary control, secondary control, and racetrack and final approach guidance. Extensive ground checks were performed on all remotely piloted systems. However, manned flight tests were the primary method of verification and validation of control law concepts developed from simulation. The design, development, and flight testing of control laws and the systems required to accomplish the remotely piloted mission are discussed.

Fluid flow electrophoresis in space

NASA Technical Reports Server (NTRS)

Griffin, R. N.

1975-01-01

Four areas relating to free-flow electrophoresis in space were investigated. The first was the degree of improvement over earthbound operations that might be expected. The second area of investigation covered the problems in developing a flowing buffer electrophoresis apparatus. The third area of investigation was the problem of testing on the ground equipment designed for use in space. The fourth area of investigation was the improvement to be expected in space for purification of biologicals. The results of some ground-based experiments are described. Other studies included cooling requirements in space, fluid sealing techniques, and measurement of voltage drop across membranes.