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Sample records for adaptive testing system

  1. The Computerized Adaptive Testing System Development Project.

    ERIC Educational Resources Information Center

    McBride, James R.; Sympson, J. B.

    The Computerized Adaptive Testing (CAT) project is a joint Armed Services coordinated effort to develop and evaluate a system for automated, adaptive administration of the Armed Services Vocational Aptitude Battery (ASVAB). The CAT is a system for administering personnel tests that differs from conventional test administration in two major…

  2. Computerized Adaptive Mastery Tests as Expert Systems.

    ERIC Educational Resources Information Center

    Frick, Theodore W.

    1992-01-01

    Discussion of expert systems and computerized adaptive tests describes two versions of EXSPRT, a new approach that combines uncertain inference in expert systems with sequential probability ratio test (SPRT) stopping rules. Results of two studies comparing EXSPRT to adaptive mastery testing based on item response theory and SPRT approaches are…

  3. A Guide to Computer Adaptive Testing Systems

    ERIC Educational Resources Information Center

    Davey, Tim

    2011-01-01

    Some brand names are used generically to describe an entire class of products that perform the same function. "Kleenex," "Xerox," "Thermos," and "Band-Aid" are good examples. The term "computerized adaptive testing" (CAT) is similar in that it is often applied uniformly across a diverse family of testing methods. Although the various members of…

  4. The Development and Evaluation of a Computerized Adaptive Testing System.

    ERIC Educational Resources Information Center

    de-la-Torre, Roberto; Vispoel, Walter P.

    The development and preliminary evaluation of the Computerized Adaptive Testing System (CATSYS), a new testing package for IBM-compatible microcomputers, are described. CATSYS can be used to administer and score operational adaptive tests or to conduct on-line computer simulation studies. The package incorporates several innovative features,…

  5. Computerized Adaptive Testing System Design: Preliminary Design Considerations.

    ERIC Educational Resources Information Center

    Croll, Paul R.

    A functional design model for a computerized adaptive testing (CAT) system was developed and presented through a series of hierarchy plus input-process-output (HIPO) diagrams. System functions were translated into system structure: specifically, into 34 software components. Implementation of the design in a physical system was addressed through…

  6. HIDEC F-15 adaptive engine control system flight test results

    NASA Technical Reports Server (NTRS)

    Smolka, James W.

    1987-01-01

    NASA-Ames' Highly Integrated Digital Electronic Control (HIDEC) flight test program aims to develop fully integrated airframe, propulsion, and flight control systems. The HIDEC F-15 adaptive engine control system flight test program has demonstrated that significant performance improvements are obtainable through the retention of stall-free engine operation throughout the aircraft flight and maneuver envelopes. The greatest thrust increase was projected for the medium-to-high altitude flight regime at subsonic speed which is of such importance to air combat. Adaptive engine control systems such as the HIDEC F-15's can be used to upgrade the performance of existing aircraft without resort to expensive reengining programs.

  7. An Adaptive Testing System for Supporting Versatile Educational Assessment

    ERIC Educational Resources Information Center

    Huang, Yueh-Min; Lin, Yen-Ting; Cheng, Shu-Chen

    2009-01-01

    With the rapid growth of computer and mobile technology, it is a challenge to integrate computer based test (CBT) with mobile learning (m-learning) especially for formative assessment and self-assessment. In terms of self-assessment, computer adaptive test (CAT) is a proper way to enable students to evaluate themselves. In CAT, students are…

  8. Computer Adaptive Testing for Small Scale Programs and Instructional Systems

    ERIC Educational Resources Information Center

    Rudner, Lawrence M.; Guo, Fanmin

    2011-01-01

    This study investigates measurement decision theory (MDT) as an underlying model for computer adaptive testing when the goal is to classify examinees into one of a finite number of groups. The first analysis compares MDT with a popular item response theory model and finds little difference in terms of the percentage of correct classifications. The…

  9. Design of a Microcomputer-Based Adaptive Testing System.

    ERIC Educational Resources Information Center

    Vale, C. David

    This paper explores the feasibility of developing a single-user microcomputer-based testing system. Testing literature was surveyed to discover types of test items that might be used in the system and to compile a list of strategies that such a system might use. Potential users were surveyed. Several were interviewed, and a questionnaire was…

  10. Evaluating Knowledge Structure-Based Adaptive Testing Algorithms and System Development

    ERIC Educational Resources Information Center

    Wu, Huey-Min; Kuo, Bor-Chen; Yang, Jinn-Min

    2012-01-01

    In recent years, many computerized test systems have been developed for diagnosing students' learning profiles. Nevertheless, it remains a challenging issue to find an adaptive testing algorithm to both shorten testing time and precisely diagnose the knowledge status of students. In order to find a suitable algorithm, four adaptive testing…

  11. Web-Based Adaptive Testing System (WATS) for Classifying Students Academic Ability

    ERIC Educational Resources Information Center

    Lee, Jaemu; Park, Sanghoon; Kim, Kwangho

    2012-01-01

    Computer Adaptive Testing (CAT) has been highlighted as a promising assessment method to fulfill two testing purposes: estimating student academic ability and classifying student academic level. In this paper, assessment for we introduced the Web-based Adaptive Testing System (WATS) developed to support a cost effective assessment for classifying…

  12. Adaptive Stress Testing of Airborne Collision Avoidance Systems

    NASA Technical Reports Server (NTRS)

    Lee, Ritchie; Kochenderfer, Mykel J.; Mengshoel, Ole J.; Brat, Guillaume P.; Owen, Michael P.

    2015-01-01

    This paper presents a scalable method to efficiently search for the most likely state trajectory leading to an event given only a simulator of a system. Our approach uses a reinforcement learning formulation and solves it using Monte Carlo Tree Search (MCTS). The approach places very few requirements on the underlying system, requiring only that the simulator provide some basic controls, the ability to evaluate certain conditions, and a mechanism to control the stochasticity in the system. Access to the system state is not required, allowing the method to support systems with hidden state. The method is applied to stress test a prototype aircraft collision avoidance system to identify trajectories that are likely to lead to near mid-air collisions. We present results for both single and multi-threat encounters and discuss their relevance. Compared with direct Monte Carlo search, this MCTS method performs significantly better both in finding events and in maximizing their likelihood.

  13. EXSPRT: An Expert Systems Approach to Computer-Based Adaptive Testing.

    ERIC Educational Resources Information Center

    Frick, Theodore W.; And Others

    Expert systems can be used to aid decision making. A computerized adaptive test (CAT) is one kind of expert system, although it is not commonly recognized as such. A new approach, termed EXSPRT, was devised that combines expert systems reasoning and sequential probability ratio test stopping rules. EXSPRT-R uses random selection of test items,…

  14. Flight test experience with an adaptive control system using a maximum likelihood parameter estimation technique

    NASA Technical Reports Server (NTRS)

    Hartmann, G.; Stein, G.; Powers, B.

    1979-01-01

    The flight test performance of an adaptive control system for the F-8 DFBW aircraft is summarized. The adaptive system is based on explicit identification of surface effectiveness parameters which are used for gain scheduling in a command augmentation system. Performance of this control law under various design parameter variations is presented. These include variations in test signal level, sample rate, and identification channel structure. Flight performance closely matches analysis and simulation predictions from previous references.

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

    NASA Technical Reports Server (NTRS)

    Gamon, M. A.

    1979-01-01

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

  16. Test techniques: A survey paper on cryogenic tunnels, adaptive wall test sections, and magnetic suspension and balance systems

    NASA Technical Reports Server (NTRS)

    Kilgore, Robert A.; Dress, David A.; Wolf, Stephen W. D.; Britcher, Colin P.

    1989-01-01

    The ability to get good experimental data in wind tunnels is often compromised by things seemingly beyond our control. Inadequate Reynolds number, wall interference, and support interference are three of the major problems in wind tunnel testing. Techniques for solving these problems are available. Cryogenic wind tunnels solve the problem of low Reynolds number. Adaptive wall test sections can go a long way toward eliminating wall interference. A magnetic suspension and balance system (MSBS) completely eliminates support interference. Cryogenic tunnels, adaptive wall test sections, and MSBS are surveyed. A brief historical overview is given and the present state of development and application in each area is described.

  17. Implementation of an Adaptive Controller System from Concept to Flight Test

    NASA Technical Reports Server (NTRS)

    Larson, Richard R.; Burken, John J.; Butler, Bradley S.; Yokum, Steve

    2009-01-01

    The National Aeronautics and Space Administration Dryden Flight Research Center (Edwards, California) is conducting ongoing flight research using adaptive controller algorithms. A highly modified McDonnell-Douglas NF-15B airplane called the F-15 Intelligent Flight Control System (IFCS) is used to test and develop these algorithms. Modifications to this airplane include adding canards and changing the flight control systems to interface a single-string research controller processor for neural network algorithms. Research goals include demonstration of revolutionary control approaches that can efficiently optimize aircraft performance in both normal and failure conditions and advancement of neural-network-based flight control technology for new aerospace system designs. This report presents an overview of the processes utilized to develop adaptive controller algorithms during a flight-test program, including a description of initial adaptive controller concepts and a discussion of modeling formulation and performance testing. Design finalization led to integration with the system interfaces, verification of the software, validation of the hardware to the requirements, design of failure detection, development of safety limiters to minimize the effect of erroneous neural network commands, and creation of flight test control room displays to maximize human situational awareness; these are also discussed.

  18. Calibration and testing of the 6.5 m MMT adaptive optics system

    NASA Astrophysics Data System (ADS)

    Johnson, Robert Lee

    2001-10-01

    This dissertation describes the development, calibration, and testing of the adaptive optics system for the 6.5 m Multiple Mirror Telescope. By employing a deformable secondary mirror, the MMT adaptive optics system uniquely solves several problems typical of astronomical adaptive optics systems. Extra components are eliminated, improving throughput and reducing emissivity. Since the adaptive secondary is integral to the telescope, a corrected beam is presented to any instrument mounted at Cassegrain focus. The testing of an adaptive mirror, which is large and convex, poses a new and difficult problem. I present a test apparatus that allows complete calibration and operation, in closed-loop, of the entire adaptive optics system in the laboratory. The test apparatus replicates the optical path of the telescope with a wavefront error of less than 500 nm RMS. To simulate atmospheric turbulence, machined acrylic plates are included. A phase-shifting interferometer allows calibration of the Shack-Hartmann wavefront sensor and reconstruction algorithms; comparisons agree to one-third of the root-mean-square wavefront. First, techniques were developed to align the apparatus and measure residual aberration. Then, the wavefront sensor was calibrated by measuring its response to introduced tilt. Lastly, a Fourier wave-optics approach was used to produce a modal wavefront reconstructor. The adaptive secondary mirror uses electro-magnetic force actuators. Capacitive position sensors are placed at each actuator to permit control of the mirror shape without measuring the reflected wavefront. These sensors have nanometer resolution, but require calibration. To calibrate the sensors, I developed a small optical instrument which measures the thickness of transparent films to an absolute accuracy of 5 nm with a precision of 2 nm. The device has applications far beyond the scope of this research. Twenty-four of these optical gap sensors have been built to calibrate the 336 capacitive

  19. International Space Station Environmental Control and Life Support System Acceptance Testing for the Pressurized Mating Adapters

    NASA Technical Reports Server (NTRS)

    Williams, David E.

    2008-01-01

    The International Space Station (ISS) Pressurized Mating Adapters (PMAs) Environmental Control and Life Support (ECLS) System is comprised of three subsystems: Atmosphere Control and Supply (ACS), Temperature and Humidity Control (THC), and Water Recovery and Management (WRM). PMAs 1 and 2 flew to ISS on Flight 2A and Pressurized Mating Adapter (PMA) 3 flew to ISS on Flight 3A. This paper provides a summary of the PMAs ECLS design and a detailed discussion of the ISS ECLS Acceptance Testing methodologies utilized for the PMAs.

  20. An Authoring Environment for Adaptive Testing

    ERIC Educational Resources Information Center

    Guzman, Eduardo; Conejo, Ricardo; Garcia-Hervas; Emilio

    2005-01-01

    SIETTE is a web-based adaptive testing system. It implements Computerized Adaptive Tests. These tests are tailor-made, theory-based tests, where questions shown to students, finalization of the test, and student knowledge estimation is accomplished adaptively. To construct these tests, SIETTE has an authoring environment comprising a suite of…

  1. Design and Flight Tests of an Adaptive Control System Employing Normal-Acceleration Command

    NASA Technical Reports Server (NTRS)

    McNeill, Water E.; McLean, John D.; Hegarty, Daniel M.; Heinle, Donovan R.

    1961-01-01

    An adaptive control system employing normal-acceleration command has been designed with the aid of an analog computer and has been flight tested. The design of the system was based on the concept of using a mathematical model in combination with a high gain and a limiter. The study was undertaken to investigate the application of a system of this type to the task of maintaining nearly constant dynamic longitudinal response of a piloted airplane over the flight envelope without relying on air data measurements for gain adjustment. The range of flight conditions investigated was between Mach numbers of 0.36 and 1.15 and altitudes of 10,000 and 40,000 feet. The final adaptive system configuration was derived from analog computer tests, in which the physical airplane control system and much of the control circuitry were included in the loop. The method employed to generate the feedback signals resulted in a model whose characteristics varied somewhat with changes in flight condition. Flight results showed that the system limited the variation in longitudinal natural frequency of the adaptive airplane to about half that of the basic airplane and that, for the subsonic cases, the damping ratio was maintained between 0.56 and 0.69. The system also automatically compensated for the transonic trim change. Objectionable features of the system were an exaggerated sensitivity of pitch attitude to gust disturbances, abnormally large pitch attitude response for a given pilot input at low speeds, and an initial delay in normal-acceleration response to pilot control at all flight conditions. The adaptive system chatter of +/-0.05 to +/-0.10 of elevon at about 9 cycles per second (resulting in a maximum airplane normal-acceleration response of from +/-0.025 g to +/- 0.035 g) was considered by the pilots to be mildly objectionable but tolerable.

  2. Flight control system development and flight test experience with the F-111 mission adaptive wing aircraft

    NASA Technical Reports Server (NTRS)

    Larson, R. R.

    1986-01-01

    The wing on the NASA F-111 transonic aircraft technology airplane was modified to provide flexible leading and trailing edge flaps. This wing is known as the mission adaptive wing (MAW) because aerodynamic efficiency can be maintained at all speeds. Unlike a conventional wing, the MAW has no spoilers, external flap hinges, or fairings to break the smooth contour. The leading edge flaps and three-segment trailing edge flaps are controlled by a redundant fly-by-wire control system that features a dual digital primary system architecture providing roll and symmetric commands to the MAW control surfaces. A segregated analog backup system is provided in the event of a primary system failure. This paper discusses the design, development, testing, qualification, and flight test experience of the MAW primary and backup flight control systems.

  3. Smart monitoring system based on adaptive current control for superconducting cable test

    NASA Astrophysics Data System (ADS)

    Arpaia, Pasquale; Ballarino, Amalia; Daponte, Vincenzo; Montenero, Giuseppe; Svelto, Cesare

    2014-12-01

    A smart monitoring system for superconducting cable test is proposed with an adaptive current control of a superconducting transformer secondary. The design, based on Fuzzy Gain Scheduling, allows the controller parameters to adapt continuously, and finely, to the working variations arising from transformer nonlinear dynamics. The control system is integrated in a fully digital control loop, with all the related benefits, i.e., high noise rejection, ease of implementation/modification, and so on. In particular, an accurate model of the system, controlled by a Fuzzy Gain Scheduler of the superconducting transformer, was achieved by an experimental campaign through the working domain at several current ramp rates. The model performance was characterized by simulation, under all the main operating conditions, in order to guide the controller design. Finally, the proposed monitoring system was experimentally validated at European Organization for Nuclear Research (CERN) in comparison to the state-of-the-art control system [P. Arpaia, L. Bottura, G. Montenero, and S. Le Naour, "Performance improvement of a measurement station for superconducting cable test," Rev. Sci. Instrum. 83, 095111 (2012)] of the Facility for the Research on Superconducting Cables, achieving a significant performance improvement: a reduction in the system overshoot by 50%, with a related attenuation of the corresponding dynamic residual error (both absolute and RMS) up to 52%.

  4. Smart monitoring system based on adaptive current control for superconducting cable test

    SciTech Connect

    Arpaia, Pasquale; Ballarino, Amalia; Montenero, Giuseppe; Daponte, Vincenzo; Svelto, Cesare

    2014-12-15

    A smart monitoring system for superconducting cable test is proposed with an adaptive current control of a superconducting transformer secondary. The design, based on Fuzzy Gain Scheduling, allows the controller parameters to adapt continuously, and finely, to the working variations arising from transformer nonlinear dynamics. The control system is integrated in a fully digital control loop, with all the related benefits, i.e., high noise rejection, ease of implementation/modification, and so on. In particular, an accurate model of the system, controlled by a Fuzzy Gain Scheduler of the superconducting transformer, was achieved by an experimental campaign through the working domain at several current ramp rates. The model performance was characterized by simulation, under all the main operating conditions, in order to guide the controller design. Finally, the proposed monitoring system was experimentally validated at European Organization for Nuclear Research (CERN) in comparison to the state-of-the-art control system [P. Arpaia, L. Bottura, G. Montenero, and S. Le Naour, “Performance improvement of a measurement station for superconducting cable test,” Rev. Sci. Instrum.83, 095111 (2012)] of the Facility for the Research on Superconducting Cables, achieving a significant performance improvement: a reduction in the system overshoot by 50%, with a related attenuation of the corresponding dynamic residual error (both absolute and RMS) up to 52%.

  5. Smart monitoring system based on adaptive current control for superconducting cable test.

    PubMed

    Arpaia, Pasquale; Ballarino, Amalia; Daponte, Vincenzo; Montenero, Giuseppe; Svelto, Cesare

    2014-12-01

    A smart monitoring system for superconducting cable test is proposed with an adaptive current control of a superconducting transformer secondary. The design, based on Fuzzy Gain Scheduling, allows the controller parameters to adapt continuously, and finely, to the working variations arising from transformer nonlinear dynamics. The control system is integrated in a fully digital control loop, with all the related benefits, i.e., high noise rejection, ease of implementation/modification, and so on. In particular, an accurate model of the system, controlled by a Fuzzy Gain Scheduler of the superconducting transformer, was achieved by an experimental campaign through the working domain at several current ramp rates. The model performance was characterized by simulation, under all the main operating conditions, in order to guide the controller design. Finally, the proposed monitoring system was experimentally validated at European Organization for Nuclear Research (CERN) in comparison to the state-of-the-art control system [P. Arpaia, L. Bottura, G. Montenero, and S. Le Naour, "Performance improvement of a measurement station for superconducting cable test," Rev. Sci. Instrum. 83, 095111 (2012)] of the Facility for the Research on Superconducting Cables, achieving a significant performance improvement: a reduction in the system overshoot by 50%, with a related attenuation of the corresponding dynamic residual error (both absolute and RMS) up to 52%. PMID:25554330

  6. Testing and integrating the laser system of ARGOS: the ground layer adaptive optics for LBT

    NASA Astrophysics Data System (ADS)

    Loose, C.; Rabien, S.; Barl, L.; Borelli, J.; Deysenroth, M.; Gaessler, W.; Gemperlein, H.; Honsberg, M.; Kulas, M.; Lederer, R.; Raab, W.; Rahmer, G.; Ziegleder, J.

    2012-07-01

    The Laser Guide Star facility ARGOS will provide Ground Layer Adaptive Optics to the Large Binocular Telescope (LBT). The system operates three pulsed laser beacons above each of the two primary mirrors, which are Rayleigh scattered in 12km height. This enables correction over a wide field of view, using the adaptive secondary mirror of the LBT. The ARGOS laser system is designed around commercially available, pulsed Nd:YAG lasers working at 532 nm. In preparation for a successful commissioning, it is important to ascertain that the specifications are met for every component of the laser system. The testing of assembled, optical subsystems is likewise necessary. In particular it is required to confirm a high output power, beam quality and pulse stability of the beacons. In a second step, the integrated laser system along with its electronic cabinets are installed on a telescope simulator. This unit is capable of carrying the whole assembly and can be tilted to imitate working conditions at the LBT. It allows alignment and functionality testing of the entire system, ensuring that flexure compensation and system diagnosis work properly in different orientations.

  7. Implementation of an Adaptive Controller System from Concept to Flight Test

    NASA Technical Reports Server (NTRS)

    Larson, Richard R.; Burken, John J.; Butler, Bradley S.

    2009-01-01

    The National Aeronautics and Space Administration Dryden Flight Research Center (Edwards, California) is conducting ongoing flight research using adaptive controller algorithms. A highly modified McDonnell-Douglas NF-15B airplane called the F-15 Intelligent Flight Control System (IFCS) was used for these algorithms. This airplane has been modified by the addition of canards and by changing the flight control systems to interface a single-string research controller processor for neural network algorithms. Research goals included demonstration of revolutionary control approaches that can efficiently optimize aircraft performance for both normal and failure conditions, and to advance neural-network-based flight control technology for new aerospace systems designs. Before the NF-15B IFCS airplane was certified for flight test, however, certain processes needed to be completed. This paper presents an overview of these processes, including a description of the initial adaptive controller concepts followed by a discussion of modeling formulation and performance testing. Upon design finalization, the next steps are: integration with the system interfaces, verification of the software, validation of the hardware to the requirements, design of failure detection, development of safety limiters to minimize the effect of erroneous neural network commands, and creation of flight test control room displays to maximize human situational awareness.

  8. Analytical Investigation of an Adaptive Flight-Control System Using a Sinusoidal Test Signal

    NASA Technical Reports Server (NTRS)

    Harris, Jack E.

    1961-01-01

    An analytical study was made of an adaptive flight-control system which measures vehicle response to small-amplitude control-surface deflections produced by a sinusoidal test signal. Changes in the response to this signal are related to environmental changes,, and the system is continuously altered to maintain this response equal to a preselected value. The system is suitable for use in high-performance aircraft and missiles and requires only the addition of a signal generator and a logic circuit consisting of a filter-rectifier network and a comparator-integrator network to a basic command-control system. Thus, it presents a relatively simple approach to the problem. The effects on system performance of variation in flight condition, system-gain level, test-signal frequency, and sensor location are included in the analysis. Longitudinal control of a high-performance research aircraft over flight conditions ranging from landing approach to a Mach number of 5.8 at an altitude of 150,000 feet, and longitudinal control of a four-stage solid-fuel missile including the first bending mode over the atmospheric portion of a launch trajectory constituted the basis for the analytical study. Results of an analog-computer study using time-varying coefficients are presented to compare the control obtained with the adaptive system with-that obtained with a fixed-gain system during the atmospheric portion of a missile launch trajectory. The system has demonstrated an ability to maintain satisfactory vehicle control-system stability over wide ranges of environmental change.

  9. A Comparison of an Expert Systems Approach to Computerized Adaptive Testing and an Item Response Theory Model.

    ERIC Educational Resources Information Center

    Frick, Theodore W.

    Expert systems can be used to aid decisionmaking. A computerized adaptive test is one kind of expert system, although not commonly recognized as such. A new approach, termed EXSPRT, was devised that combines expert systems reasoning and sequential probability ratio test stopping rules. Two versions of EXSPRT were developed, one with random…

  10. Testing Local Adaptation in a Natural Great Tit-Malaria System: An Experimental Approach

    PubMed Central

    Jenkins, Tania; Delhaye, Jessica; Christe, Philippe

    2015-01-01

    Finding out whether Plasmodium spp. are coevolving with their vertebrate hosts is of both theoretical and applied interest and can influence our understanding of the effects and dynamics of malaria infection. In this study, we tested for local adaptation as a signature of coevolution between malaria blood parasites, Plasmodium spp. and its host, the great tit, Parus major. We conducted a reciprocal transplant experiment of birds in the field, where we exposed birds from two populations to Plasmodium parasites. This experimental set-up also provided a unique opportunity to study the natural history of malaria infection in the wild and to assess the effects of primary malaria infection on juvenile birds. We present three main findings: i) there was no support for local adaptation; ii) there was a male-biased infection rate; iii) infection occurred towards the end of the summer and differed between sites. There were also site-specific effects of malaria infection on the hosts. Taken together, we present one of the few experimental studies of parasite-host local adaptation in a natural malaria system, and our results shed light on the effects of avian malaria infection in the wild. PMID:26555892

  11. Leak test adapter for containers

    DOEpatents

    Hallett, Brian H.; Hartley, Michael S.

    1996-01-01

    An adapter is provided for facilitating the charging of containers and leak testing penetration areas. The adapter comprises an adapter body and stem which are secured to the container's penetration areas. The container is then pressurized with a tracer gas. Manipulating the adapter stem installs a penetration plug allowing the adapter to be removed and the penetration to be leak tested with a mass spectrometer. Additionally, a method is provided for using the adapter.

  12. Adaptability test of lettuce to soil-like substrate in bioregenerative life support system

    NASA Astrophysics Data System (ADS)

    Min, Yan; Liu, Professor Hong; Wenting, Fu

    Plant cultivation using soil-like substrate (SLS) is considered to be a feasible option for building up matter for biological turnover in bioregenerative life support system (BLSS) by many researchers. The characteristics of SLS are different from those of true soil therefore it is very important to study the adaptability of candidate crop to SLS in BLSS. This study was carried out in three successive steps to test the adaptability of lettuce (Lactuca sativa L.) to rice straw SLS in BLSS of China. First, six Chinese specific lettuce cultivars which were selected for Chinese advanced life support system were planted into the same rice straw SLS, which was to determine the more suitable plant cultivar to do the next experiment. The results showed that Sharp Leaf lettuce and Red lettuce were more suitable for SLS than other cultivars. Second, the possibility of increasing the crop yield on the SLS was conducted by changing the soil depth and plant density. Sharp Leaf lettuce and Red lettuce were used into this experiment in order to obtain the highest yield under the smallest soil volume and weight at the same light intensity. Crop edible biomass, crop nutrition content and photosynthetic characteristics were estimated during the experiment. Red lettuce obtained higher biomass and photosynthesis capacity. Lastly, the stability of planting system of lettuce and SLS was evaluated in the closed controlled system. Red lettuce would be the test plant. In this experiment different age lettuce groups would be planted together and gas exchange would be measured. In all of these experiments soil physical and chemical characteristics were also be measured which will be the basal data for further research.

  13. Full-system laboratory testing of the F/15 deformable secondary mirror for the new MMT adaptive optics system

    NASA Astrophysics Data System (ADS)

    Mcguire, Patrick C.; Lloyd-Hart, Michael; Angel, J. Roger P.; Angeli, George Z.; Johnson, Robert L.; Fitz-Patrick, Bruce C.; Davison, Warren B.; Sarlot, Roland J.; Bresloff, Cynthia J.; Hughes, John M.; Miller, Stephen M.; Schaller, Skip; Wildi, Francois P.; Kenworthy, Matthew A.; Cordova, Richard M.; Rademacher, Matthew J.; Rascon, Mario H.; Burge, James H.; Stamper, Brian L.; Zhao, Chunyu; Salinari, Piero; del Vecchio, Ciro; Riccardi, Armando; Brusa, Guido; Biasi, Roberto; Andrighettoni, Mario; Gallieni, Daniele; Franchini, Claudio; Sandler, David G.; Barrett, Todd K.

    1999-09-01

    We will present a system to perform closed-loop optical tests of the 64 cm diameter, 336 actuator adaptive secondary made at the Steward Observatory Mirror Laboratory. Testing will include Shack-Hartmann wavefront sensing and modal correction of static and dynamic aberrated wavefronts. The test optical system is designed so that experiments can be made with both the focal plane instrument and secondary installed in their normal configuration at the MMT, or with the same 9 m spacing in a laboratory test tower. The convex secondary will be illuminated at normal incidence through two 70 cm diameter lenses mounted just below. The artificial, aberrated star is projected from near the wavefront sensor in the Cassegrain focus assembly. Computer generated holograms correct for spherical aberration in the really optics at the test wavelengths of 0.594 and 1.5 micrometers . Atmospheric turbulence is reproduced by two spinning transmission plates imprinted with Kolmogorov turbulence. The Shimmulator will give us the opportunity to test fully the adaptive optics system before installation at the new MMT, hence saving much precious telescope time.

  14. Participation in Decision Making as a Property of Complex Adaptive Systems: Developing and Testing a Measure

    PubMed Central

    Anderson, Ruth A.; Hsieh, Pi-Ching; Su, Hui Fang; Landerman, Lawrence R.; McDaniel, Reuben R.

    2013-01-01

    Objectives. To (1) describe participation in decision-making as a systems-level property of complex adaptive systems and (2) present empirical evidence of reliability and validity of a corresponding measure. Method. Study 1 was a mail survey of a single respondent (administrators or directors of nursing) in each of 197 nursing homes. Study 2 was a field study using random, proportionally stratified sampling procedure that included 195 organizations with 3,968 respondents. Analysis. In Study 1, we analyzed the data to reduce the number of scale items and establish initial reliability and validity. In Study 2, we strengthened the psychometric test using a large sample. Results. Results demonstrated validity and reliability of the participation in decision-making instrument (PDMI) while measuring participation of workers in two distinct job categories (RNs and CNAs). We established reliability at the organizational level aggregated items scores. We established validity of the multidimensional properties using convergent and discriminant validity and confirmatory factor analysis. Conclusions. Participation in decision making, when modeled as a systems-level property of organization, has multiple dimensions and is more complex than is being traditionally measured. Managers can use this model to form decision teams that maximize the depth and breadth of expertise needed and to foster connection among them. PMID:24349771

  15. Flight Test of an Adaptive Configuration Optimization System for Transport Aircraft

    NASA Technical Reports Server (NTRS)

    Gilyard, Glenn B.; Georgie, Jennifer; Barnicki, Joseph S.

    1999-01-01

    A NASA Dryden Flight Research Center program explores the practical application of real-time adaptive configuration optimization for enhanced transport performance on an L-1011 aircraft. This approach is based on calculation of incremental drag from forced-response, symmetric, outboard aileron maneuvers. In real-time operation, the symmetric outboard aileron deflection is directly optimized, and the horizontal stabilator and angle of attack are indirectly optimized. A flight experiment has been conducted from an onboard research engineering test station, and flight research results are presented herein. The optimization system has demonstrated the capability of determining the minimum drag configuration of the aircraft in real time. The drag-minimization algorithm is capable of identifying drag to approximately a one-drag-count level. Optimizing the symmetric outboard aileron position realizes a drag reduction of 2-3 drag counts (approximately 1 percent). Algorithm analysis of maneuvers indicate that two-sided raised-cosine maneuvers improve definition of the symmetric outboard aileron drag effect, thereby improving analysis results and consistency. Ramp maneuvers provide a more even distribution of data collection as a function of excitation deflection than raised-cosine maneuvers provide. A commercial operational system would require airdata calculations and normal output of current inertial navigation systems; engine pressure ratio measurements would be optional.

  16. Verification and Validation of Adaptive and Intelligent Systems with Flight Test Results

    NASA Technical Reports Server (NTRS)

    Burken, John J.; Larson, Richard R.

    2009-01-01

    F-15 IFCS project goals are: a) Demonstrate Control Approaches that can Efficiently Optimize Aircraft Performance in both Normal and Failure Conditions [A] & [B] failures. b) Advance Neural Network-Based Flight Control Technology for New Aerospace Systems Designs with a Pilot in the Loop. Gen II objectives include; a) Implement and Fly a Direct Adaptive Neural Network Based Flight Controller; b) Demonstrate the Ability of the System to Adapt to Simulated System Failures: 1) Suppress Transients Associated with Failure; 2) Re-Establish Sufficient Control and Handling of Vehicle for Safe Recovery. c) Provide Flight Experience for Development of Verification and Validation Processes for Flight Critical Neural Network Software.

  17. An atmospheric turbulence generator for dynamic tests with LINC-NIRVANA's adaptive optics system

    NASA Astrophysics Data System (ADS)

    Meschke, D.; Bizenberger, P.; Gaessler, W.; Zhang, X.; Mohr, L.; Baumeister, H.; Diolaiti, E.

    2010-07-01

    LINC-NIRVANA[1] (LN) is an instrument for the Large Binocular Telescope[2] (LBT). Its purpose is to combine the light coming from the two primary mirrors in a Fizeau-type interferometer. In order to compensate turbulence-induced dynamic aberrations, the layer oriented adaptive optics system of LN[3] consists of two major subsystems for each side: the Ground-Layer-Wavefront sensor (GLWS) and the Mid- and High-Layer Wavefront sensor (MHLWS). The MHLWS is currently set up in a laboratory at the Max-Planck-Institute for Astronomy in Heidelberg. To test the multi-conjugate AO with multiple simulated stars in the laboratory and to develop the necessary control software, a dedicated light source is needed. For this reason, we designed an optical system, operating in visible as well as in infrared light, which imitates the telescope's optical train (f-ratio, pupil position and size, field curvature). By inserting rotating surface etched glass phase screens, artificial aberrations corresponding to the atmospheric turbulence are introduced. In addition, different turbulence altitudes can be simulated depending on the position of these screens along the optical axis. In this way, it is possible to comprehensively test the complete system, including electronics and software, in the laboratory before integration into the final LINC-NIRVANA setup. Combined with an atmospheric piston simulator, also this effect can be taken into account. Since we are building two identical sets, it is possible to feed the complete instrument with light for the interferometric combination during the assembly phase in the integration laboratory.

  18. Applying Adaptive Variables in Computerised Adaptive Testing

    ERIC Educational Resources Information Center

    Triantafillou, Evangelos; Georgiadou, Elissavet; Economides, Anastasios A.

    2007-01-01

    Current research in computerised adaptive testing (CAT) focuses on applications, in small and large scale, that address self assessment, training, employment, teacher professional development for schools, industry, military, assessment of non-cognitive skills, etc. Dynamic item generation tools and automated scoring of complex, constructed…

  19. Cortisol profiles: A test for adaptive calibration of the stress response system in maltreated and nonmaltreated youth.

    PubMed

    Peckins, Melissa K; Susman, Elizabeth J; Negriff, Sonya; Noll, Jennie; Trickett, Penelope K

    2015-11-01

    Throughout the life span, exposure to chronic stress such as child maltreatment is thought to contribute to future dysfunction of the stress response system (SRS) through the process of adaptive calibration. Dysfunction of the SRS is associated with numerous health and behavior problems, so it is important to understand under what conditions and what time frame adaptive calibration occurs. The present study tested for adaptive calibration of the SRS in a sample of maltreated (n = 303) and nonmaltreated (n = 151) youth during the important developmental period of adolescence. Data were used from Waves 2, 3, and 4 of a larger study of the consequences of maltreatment on health and well-being. At each time point, participants underwent the Trier Social Stress Test for Children and provided a baseline and four poststressor saliva samples to measure cortisol reactivity. Adaptive calibration was tested by performing a latent profile analysis using the five samples of salivary cortisol provided at each time point, and testing whether maltreatment status predicted the likelihood of profile membership at Time 2, Time 3, and Time 4. Three cortisol profiles emerged from the data at each time point (blunted, moderate, and elevated), and results indicated that maltreated youth were more likely than nonmaltreated youth to present with the blunted cortisol profile compared to the moderate and elevated profiles at Time 2 and Time 3, even after controlling for recent exposure to violence and trauma. At Time 4, there was no longer a difference in profile membership between maltreated and nonmaltreated youth, suggesting adaptive calibration may be a lengthy process requiring a period of years to become evident. Overall, the findings provide support for adaptive calibration and offer insight into the conditions under which adaptive calibration occurs. PMID:26535937

  20. Implementation of an Adaptive Controller System from Concept to Flight Test

    NASA Technical Reports Server (NTRS)

    Larson, Richard R.; Burken, John J.; Butler, Bradley S.; Yokum, Steve

    2009-01-01

    The National Aeronautics and Space Administration (NASA) at the Dryden Flight Research Center (DFRC) has been conducting flight-test research using an F-15 aircraft (figure 1). This aircraft has been specially modified to interface a neural net (NN) controller as part of a single-string Airborne Research Test System (ARTS) computer with the existing quad-redundant flight control system (FCC) shown in figure 2. The NN commands are passed to FCC channels 2 and 4 and are cross channel data linked (CCDL) to the other computers as shown. Numerous types of fault-detection monitors exist in the FCC when the NN mode is engaged; these monitors would cause an automatic disengagement of the NN in the event of a triggering fault. Unfortunately, these monitors still may not prevent a possible NN hard-over command from coming through to the control laws. Therefore, an additional and unique safety monitor was designed for a single-string source that allows authority at maximum actuator rates but protects the pilot and structural loads against excessive g-limits in the case of a NN hard-over command input. This additional monitor resides in the FCCs and is executed before the control laws are computed. This presentation describes a "floating limiter" (FL) concept that was developed and successfully test-flown for this program (figure 3). The FL computes the rate of change of the NN commands that are input to the FCC from the ARTS. A window is created with upper and lower boundaries, which is constantly "floating" and trying to stay centered as the NN command rates are changing. The limiter works by only allowing the window to move at a much slower rate than those of the NN commands. Anywhere within the window, however, full rates are allowed. If a rate persists in one direction, it will eventually "hit" the boundary and be rate-limited to the floating limiter rate. When this happens, a persistent counter begins and after a limit is reached, a NN disengage command is generated. The

  1. Performance Testing of an Off-Limb Solar Adaptive Optics System

    NASA Astrophysics Data System (ADS)

    Taylor, G. E.; Schmidt, D.; Marino, J.; Rimmele, T. R.; McAteer, R. T. J.

    2015-06-01

    Long-exposure spectro-polarimetry in the near-infrared is a preferred method to measure the magnetic field and other physical properties of solar prominences. In the past, it has been very difficult to observe prominences in this way with sufficient spatial resolution to fully understand their dynamical properties. Solar prominences contain highly transient structures, visible only at small spatial scales; hence they must be observed at sub-arcsecond resolution, with a high temporal cadence. An adaptive optics (AO) system capable of directly locking on to prominence structure away from the solar limb has the potential to allow for diffraction-limited spectro-polarimetry of solar prominences. We show the performance of the off-limb AO system and its expected performance at the desired science wavelength Ca ii 8542 Å.

  2. An adaptable, low cost test-bed for unmanned vehicle systems research

    NASA Astrophysics Data System (ADS)

    Goppert, James M.

    2011-12-01

    An unmanned vehicle systems test-bed has been developed. The test-bed has been designed to accommodate hardware changes and various vehicle types and algorithms. The creation of this test-bed allows research teams to focus on algorithm development and employ a common well-tested experimental framework. The ArduPilotOne autopilot was developed to provide the necessary level of abstraction for multiple vehicle types. The autopilot was also designed to be highly integrated with the Mavlink protocol for Micro Air Vehicle (MAV) communication. Mavlink is the native protocol for QGroundControl, a MAV ground control program. Features were added to QGroundControl to accommodate outdoor usage. Next, the Mavsim toolbox was developed for Scicoslab to allow hardware-in-the-loop testing, control design and analysis, and estimation algorithm testing and verification. In order to obtain linear models of aircraft dynamics, the JSBSim flight dynamics engine was extended to use a probabilistic Nelder-Mead simplex method. The JSBSim aircraft dynamics were compared with wind-tunnel data collected. Finally, a structured methodology for successive loop closure control design is proposed. This methodology is demonstrated along with the rest of the test-bed tools on a quadrotor, a fixed wing RC plane, and a ground vehicle. Test results for the ground vehicle are presented.

  3. Surveillance system and method having an adaptive sequential probability fault detection test

    NASA Technical Reports Server (NTRS)

    Herzog, James P. (Inventor); Bickford, Randall L. (Inventor)

    2005-01-01

    System and method providing surveillance of an asset such as a process and/or apparatus by providing training and surveillance procedures that numerically fit a probability density function to an observed residual error signal distribution that is correlative to normal asset operation and then utilizes the fitted probability density function in a dynamic statistical hypothesis test for providing improved asset surveillance.

  4. Surveillance System and Method having an Adaptive Sequential Probability Fault Detection Test

    NASA Technical Reports Server (NTRS)

    Bickford, Randall L. (Inventor); Herzog, James P. (Inventor)

    2008-01-01

    System and method providing surveillance of an asset such as a process and/or apparatus by providing training and surveillance procedures that numerically fit a probability density function to an observed residual error signal distribution that is correlative to normal asset operation and then utilizes the fitted probability density function in a dynamic statistical hypothesis test for providing improved asset surveillance.

  5. Surveillance system and method having an adaptive sequential probability fault detection test

    NASA Technical Reports Server (NTRS)

    Bickford, Randall L. (Inventor); Herzog, James P. (Inventor)

    2006-01-01

    System and method providing surveillance of an asset such as a process and/or apparatus by providing training and surveillance procedures that numerically fit a probability density function to an observed residual error signal distribution that is correlative to normal asset operation and then utilizes the fitted probability density function in a dynamic statistical hypothesis test for providing improved asset surveillance.

  6. Flight Testing of the Space Launch System (SLS) Adaptive Augmenting Control (AAC) Algorithm on an F/A-18

    NASA Technical Reports Server (NTRS)

    Dennehy, Cornelius J.; VanZwieten, Tannen S.; Hanson, Curtis E.; Wall, John H.; Miller, Chris J.; Gilligan, Eric T.; Orr, Jeb S.

    2014-01-01

    The Marshall Space Flight Center (MSFC) Flight Mechanics and Analysis Division developed an adaptive augmenting control (AAC) algorithm for launch vehicles that improves robustness and performance on an as-needed basis by adapting a classical control algorithm to unexpected environments or variations in vehicle dynamics. This was baselined as part of the Space Launch System (SLS) flight control system. The NASA Engineering and Safety Center (NESC) was asked to partner with the SLS Program and the Space Technology Mission Directorate (STMD) Game Changing Development Program (GCDP) to flight test the AAC algorithm on a manned aircraft that can achieve a high level of dynamic similarity to a launch vehicle and raise the technology readiness of the algorithm early in the program. This document reports the outcome of the NESC assessment.

  7. Verification of Adaptive Systems

    SciTech Connect

    Pullum, Laura L; Cui, Xiaohui; Vassev, Emil; Hinchey, Mike; Rouff, Christopher; Buskens, Richard

    2012-01-01

    Adaptive systems are critical for future space and other unmanned and intelligent systems. Verification of these systems is also critical for their use in systems with potential harm to human life or with large financial investments. Due to their nondeterministic nature and extremely large state space, current methods for verification of software systems are not adequate to provide a high level of assurance for them. The combination of stabilization science, high performance computing simulations, compositional verification and traditional verification techniques, plus operational monitors, provides a complete approach to verification and deployment of adaptive systems that has not been used before. This paper gives an overview of this approach.

  8. Testing HyDE on ADAPT

    NASA Technical Reports Server (NTRS)

    Sweet, Adam

    2008-01-01

    The IVHM Project in the Aviation Safety Program has funded research in electrical power system (EPS) health management. This problem domain contains both discrete and continuous behavior, and thus is directly relevant for the hybrid diagnostic tool HyDE. In FY2007 work was performed to expand the HyDE diagnosis model of the ADAPT system. The work completed resulted in a HyDE model with the capability to diagnose five times the number of ADAPT components previously tested. The expanded diagnosis model passed a corresponding set of new ADAPT fault injection scenario tests with no incorrect faults reported. The time required for the HyDE diagnostic system to isolate the fault varied widely between tests; this variance was reduced by tuning HyDE input parameters. These results and other diagnostic design trade-offs are discussed. Finally, possible future improvements for both the HyDE diagnostic model and HyDE itself are presented.

  9. Rotationally Adaptive Flight Test Surface

    NASA Technical Reports Server (NTRS)

    Barrett, Ron

    1999-01-01

    Research on a new design of flutter exciter vane using adaptive materials was conducted. This novel design is based on all-moving aerodynamic surface technology and consists of a structurally stiff main spar, a series of piezoelectric actuator elements and an aerodynamic shell which is pivoted around the main spar. The work was built upon the current missile-type all-moving surface designs and change them so they are better suited for flutter excitation through the transonic flight regime. The first portion of research will be centered on aerodynamic and structural modeling of the system. USAF DatCom and vortex lattice codes was used to capture the fundamental aerodynamics of the vane. Finite element codes and laminated plate theory and virtual work analyses will be used to structurally model the aerodynamic vane and wing tip. Following the basic modeling, a flutter test vane was designed. Each component within the structure was designed to meet the design loads. After the design loads are met, then the deflections will be maximized and the internal structure will be laid out. In addition to the structure, a basic electrical control network will be designed which will be capable of driving a scaled exciter vane. The third and final stage of main investigation involved the fabrication of a 1/4 scale vane. This scaled vane was used to verify kinematics and structural mechanics theories on all-moving actuation. Following assembly, a series of bench tests was conducted to determine frequency response, electrical characteristics, mechanical and kinematic properties. Test results indicate peak-to-peak deflections of 1.1 deg with a corner frequency of just over 130 Hz.

  10. Adaptive security systems -- Combining expert systems with adaptive technologies

    SciTech Connect

    Argo, P.; Loveland, R.; Anderson, K.

    1997-09-01

    The Adaptive Multisensor Integrated Security System (AMISS) uses a variety of computational intelligence techniques to reason from raw sensor data through an array of processing layers to arrive at an assessment for alarm/alert conditions based on human behavior within a secure facility. In this paper, the authors give an overview of the system and briefly describe some of the major components of the system. This system is currently under development and testing in a realistic facility setting.

  11. Simulation and experimental tests on active mass damper control system based on Model Reference Adaptive Control algorithm

    NASA Astrophysics Data System (ADS)

    Tu, Jianwei; Lin, Xiaofeng; Tu, Bo; Xu, Jiayun; Tan, Dongmei

    2014-09-01

    In the process of sudden natural disasters (such as earthquake or typhoon), the active mass damper (AMD) system can reduce the structural vibration response optimally, which serves as a frequently applied but less mature vibration-reducing technology in wind and earthquake resistance of high-rise buildings. As the core of this technology, the selection of control algorithm is extremely challenging due to the uncertainty of structural parameters and the randomness of external loads. It is not necessary for the Model Reference Adaptive Control (MRAC) based on the Minimal Controller Synthesis (MCS) algorithm to know in advance the structural parameters, which produces special advantages in conditions of real-time change of system parameters, uncertain external disturbance, and the nonlinear dynamic system. This paper studies the application of the MRAC into the AMD active control system. The principle of MRAC algorithm is recommended and the dynamic model and the motion differential equation of AMD system based on MRAC is established under seismic excitation. The simulation analysis for linear and nonlinear structures when the structural stiffness is degenerated is performed under AMD system controlled by MRAC algorithm. To verify the validity of the MRAC over the AMD system, experimental tests are carried out on a linear structure and a structure with variable stiffness with the AMD system under seismic excitation on the shake table, and the experimental results are compared with those of the traditional pole assignment control algorithm.

  12. Measuring acuity of the approximate number system reliably and validly: the evaluation of an adaptive test procedure

    PubMed Central

    Lindskog, Marcus; Winman, Anders; Juslin, Peter; Poom, Leo

    2013-01-01

    Two studies investigated the reliability and predictive validity of commonly used measures and models of Approximate Number System acuity (ANS). Study 1 investigated reliability by both an empirical approach and a simulation of maximum obtainable reliability under ideal conditions. Results showed that common measures of the Weber fraction (w) are reliable only when using a substantial number of trials, even under ideal conditions. Study 2 compared different purported measures of ANS acuity as for convergent and predictive validity in a within-subjects design and evaluated an adaptive test using the ZEST algorithm. Results showed that the adaptive measure can reduce the number of trials needed to reach acceptable reliability. Only direct tests with non-symbolic numerosity discriminations of stimuli presented simultaneously were related to arithmetic fluency. This correlation remained when controlling for general cognitive ability and perceptual speed. Further, the purported indirect measure of ANS acuity in terms of the Numeric Distance Effect (NDE) was not reliable and showed no sign of predictive validity. The non-symbolic NDE for reaction time was significantly related to direct w estimates in a direction contrary to the expected. Easier stimuli were found to be more reliable, but only harder (7:8 ratio) stimuli contributed to predictive validity. PMID:23964256

  13. NEEDS - Information Adaptive System

    NASA Technical Reports Server (NTRS)

    Kelly, W. L.; Benz, H. F.; Meredith, B. D.

    1980-01-01

    The Information Adaptive System (IAS) is an element of the NASA End-to-End Data System (NEEDS) Phase II and is focused toward onboard image processing. The IAS is a data preprocessing system which is closely coupled to the sensor system. Some of the functions planned for the IAS include sensor response nonuniformity correction, geometric correction, data set selection, data formatting, packetization, and adaptive system control. The inclusion of these sensor data preprocessing functions onboard the spacecraft will significantly improve the extraction of information from the sensor data in a timely and cost effective manner, and provide the opportunity to design sensor systems which can be reconfigured in near real-time for optimum performance. The purpose of this paper is to present the preliminary design of the IAS and the plans for its development.

  14. A CEFR-Based Computerized Adaptive Testing System for Chinese Proficiency

    ERIC Educational Resources Information Center

    Wang, Hsuan-Po; Kuo, Bor-Chen; Tsai, Ya-Hsun; Liao, Chen-Huei

    2012-01-01

    In the era of globalization, the trend towards learning Chinese as a foreign language (CFL) has become increasingly popular worldwide. The increasing demand in learning CFL has raised the profile of the Chinese proficiency test (CPT). This study will analyze in depth the inadequacy of current CPT's utilizing the common European framework of…

  15. Development and Testing of a Fully Adaptable Membrane Bioreactor Fouling Model for a Sidestream Configuration System

    PubMed Central

    Paul, Parneet

    2013-01-01

    A dead-end filtration model that includes the three main fouling mechanisms mentioned in Hermia (i.e., cake build-up, complete pore blocking, and pore constriction) and that was based on a constant trans-membrane pressure (TMP) operation was extensively modified so it could be used for a sidestream configuration membrane bioreactor (MBR) situation. Modifications and add-ons to this basic model included: alteration so that it could be used for varying flux and varying TMP operations; inclusion of a backwash mode; it described pore constriction (i.e., irreversible fouling) in relation to the concentration of soluble microbial products (SMP) in the liquor; and, it could be used in a cross flow scenario by the addition of scouring terms in the model formulation. The additional terms in this modified model were checked against an already published model to see if they made sense, physically speaking. Next this modified model was calibrated and validated in Matlab© using data collected by carrying out flux stepping tests on both a pilot sidestream MBR plant, and then a pilot membrane filtration unit. The model fit proved good, especially for the pilot filtration unit data. In conclusion, this model formulation is of the right level of complexity to be used for most practical MBR situations. PMID:24958618

  16. Adaptive flutter suppression, analysis and test

    NASA Technical Reports Server (NTRS)

    Johnson, E. H.; Hwang, C.; Joshi, D. S.; Harvey, C. A.; Huttsell, L. T.; Farmer, M. G.

    1983-01-01

    Methods of adaptive control have been applied to suppress a potentially violent flutter condition of a half-span model of a lightweight figher aircraft. This marked the confluence of several technologies with active flutter suppression, digital control and adaptive control theory the primary contributors. The control algorithm was required to adapt both to slowly varying changes, corresponding to changes in the flight condition or fuel loading and to rapid changes, corresponding to a store release or the transition from a stable to an unstable flight condition. The development of the adaptive control methods was followed by a simulation and checkout of the complete system and a wind tunnel demonstration. As part of the test, a store was released from the model wing tip, transforming the model abruptly from a stable configuration to a violent flutter condition. The adaptive algorithm recognized the unstable nature of the resulting configuration and implemented a stabilizing control law in a fraction of a second. The algorithm was also shown to provide system stability over a range of wind tunnel Mach numbers and dynamic pressures.

  17. Equating Scores from Adaptive to Linear Tests

    ERIC Educational Resources Information Center

    van der Linden, Wim J.

    2006-01-01

    Two local methods for observed-score equating are applied to the problem of equating an adaptive test to a linear test. In an empirical study, the methods were evaluated against a method based on the test characteristic function (TCF) of the linear test and traditional equipercentile equating applied to the ability estimates on the adaptive test…

  18. Flight Test Results from the NF-15B Intelligent Flight Control System (IFCS) Project with Adaptation to a Simulated Stabilator Failure

    NASA Technical Reports Server (NTRS)

    Bosworth, John T.; Williams-Hayes, Peggy S.

    2007-01-01

    Adaptive flight control systems have the potential to be more resilient to extreme changes in airplane behavior. Extreme changes could be a result of a system failure or of damage to the airplane. A direct adaptive neural-network-based flight control system was developed for the National Aeronautics and Space Administration NF-15B Intelligent Flight Control System airplane and subjected to an inflight simulation of a failed (frozen) (unmovable) stabilator. Formation flight handling qualities evaluations were performed with and without neural network adaptation. The results of these flight tests are presented. Comparison with simulation predictions and analysis of the performance of the adaptation system are discussed. The performance of the adaptation system is assessed in terms of its ability to decouple the roll and pitch response and reestablish good onboard model tracking. Flight evaluation with the simulated stabilator failure and adaptation engaged showed that there was generally improvement in the pitch response; however, a tendency for roll pilot-induced oscillation was experienced. A detailed discussion of the cause of the mixed results is presented.

  19. Flight Test Results from the NF-15B Intelligent Flight Control System (IFCS) Project with Adaptation to a Simulated Stabilator Failure

    NASA Technical Reports Server (NTRS)

    Bosworth, John T.; Williams-Hayes, Peggy S.

    2010-01-01

    Adaptive flight control systems have the potential to be more resilient to extreme changes in airplane behavior. Extreme changes could be a result of a system failure or of damage to the airplane. A direct adaptive neural-network-based flight control system was developed for the National Aeronautics and Space Administration NF-15B Intelligent Flight Control System airplane and subjected to an inflight simulation of a failed (frozen) (unmovable) stabilator. Formation flight handling qualities evaluations were performed with and without neural network adaptation. The results of these flight tests are presented. Comparison with simulation predictions and analysis of the performance of the adaptation system are discussed. The performance of the adaptation system is assessed in terms of its ability to decouple the roll and pitch response and reestablish good onboard model tracking. Flight evaluation with the simulated stabilator failure and adaptation engaged showed that there was generally improvement in the pitch response; however, a tendency for roll pilot-induced oscillation was experienced. A detailed discussion of the cause of the mixed results is presented.

  20. Adaptive ophthalmologic system

    DOEpatents

    Olivier, Scot S.; Thompson, Charles A.; Bauman, Brian J.; Jones, Steve M.; Gavel, Don T.; Awwal, Abdul A.; Eisenbies, Stephen K.; Haney, Steven J.

    2007-03-27

    A system for improving vision that can diagnose monochromatic aberrations within a subject's eyes, apply the wavefront correction, and then enable the patient to view the results of the correction. The system utilizes a laser for producing a beam of light; a corrector; a wavefront sensor; a testing unit; an optic device for directing the beam of light to the corrector, to the retina, from the retina to the wavefront sensor, and to the testing unit; and a computer operatively connected to the wavefront sensor and the corrector.

  1. Test Information Targeting Strategies for Adaptive Multistage Testing Designs.

    ERIC Educational Resources Information Center

    Luecht, Richard M.; Burgin, William

    Adaptive multistage testlet (MST) designs appear to be gaining popularity for many large-scale computer-based testing programs. These adaptive MST designs use a modularized configuration of preconstructed testlets and embedded score-routing schemes to prepackage different forms of an adaptive test. The conditional information targeting (CIT)…

  2. Bayesian integrated testing strategy (ITS) for skin sensitization potency assessment: a decision support system for quantitative weight of evidence and adaptive testing strategy.

    PubMed

    Jaworska, Joanna S; Natsch, Andreas; Ryan, Cindy; Strickland, Judy; Ashikaga, Takao; Miyazawa, Masaaki

    2015-12-01

    The presented Bayesian network Integrated Testing Strategy (ITS-3) for skin sensitization potency assessment is a decision support system for a risk assessor that provides quantitative weight of evidence, leading to a mechanistically interpretable potency hypothesis, and formulates adaptive testing strategy for a chemical. The system was constructed with an aim to improve precision and accuracy for predicting LLNA potency beyond ITS-2 (Jaworska et al., J Appl Toxicol 33(11):1353-1364, 2013) by improving representation of chemistry and biology. Among novel elements are corrections for bioavailability both in vivo and in vitro as well as consideration of the individual assays' applicability domains in the prediction process. In ITS-3 structure, three validated alternative assays, DPRA, KeratinoSens and h-CLAT, represent first three key events of the adverse outcome pathway for skin sensitization. The skin sensitization potency prediction is provided as a probability distribution over four potency classes. The probability distribution is converted to Bayes factors to: 1) remove prediction bias introduced by the training set potency distribution and 2) express uncertainty in a quantitative manner, allowing transparent and consistent criteria to accept a prediction. The novel ITS-3 database includes 207 chemicals with a full set of in vivo and in vitro data. The accuracy for predicting LLNA outcomes on the external test set (n = 60) was as follows: hazard (two classes)-100 %, GHS potency classification (three classes)-96 %, potency (four classes)-89 %. This work demonstrates that skin sensitization potency prediction based on data from three key events, and often less, is possible, reliable over broad chemical classes and ready for practical applications. PMID:26612363

  3. Flight Test Approach to Adaptive Control Research

    NASA Technical Reports Server (NTRS)

    Pavlock, Kate Maureen; Less, James L.; Larson, David Nils

    2011-01-01

    The National Aeronautics and Space Administration s Dryden Flight Research Center completed flight testing of adaptive controls research on a full-scale F-18 testbed. The validation of adaptive controls has the potential to enhance safety in the presence of adverse conditions such as structural damage or control surface failures. This paper describes the research interface architecture, risk mitigations, flight test approach and lessons learned of adaptive controls research.

  4. Constructing Rotating Item Pools for Constrained Adaptive Testing

    ERIC Educational Resources Information Center

    Ariel, Adelaide; Veldkamp, Bernard P.; van der Linden, Wim J.

    2004-01-01

    Preventing items in adaptive testing from being over- or underexposed is one of the main problems in computerized adaptive testing. Though the problem of overexposed items can be solved using a probabilistic item-exposure control method, such methods are unable to deal with the problem of underexposed items. Using a system of rotating item pools,…

  5. The ESO Adaptive Optics Facility under Test

    NASA Astrophysics Data System (ADS)

    Arsenault, Robin; Madec, Pierre-Yves; Paufique, Jerome; La Penna, Paolo; Stroebele, Stefan; Vernet, Elise; Pirard, Jean-François; Hackenberg, Wolfgang; Kuntschner, Harald; Kolb, Johann; Muller, Nicolas; Le Louarn, Miska; Amico, Paola; Hubin, Norbert; Lizon, Jean-Louis; Ridings, Rob; Abad, Jose; Fischer, Gert; Heinz, Volker; Kiekebusch, Mario; Argomedo, Javier; Conzelmann, Ralf; Tordo, Sebastien; Donaldson, Rob; Soenke, Christian; Duhoux, Philippe; Fedrigo, Enrico; Delabre, Bernard; Jost, Andrea; Duchateau, Michel; Downing, Mark; Moreno, Javier; Manescau, Antonio; Bonaccini Calia, Domenico; Quattri, Marco; Dupuy, Christophe; Guidolin, Ivan; Comin, Mauro; Guzman, Ronald; Buzzoni, Bernard; Quentin, Jutta; Lewis, Steffan; Jolley, Paul; Kraus, Max; Pfrommer, Thomas; Garcia-Rissmann, Aurea; Biasi, Roberto; Gallieni, Daniele; Stuik, Remko

    2013-12-01

    The Adaptive Optics Facility project has received most of its subsystems in Garching and the ESO Integration Hall has become the central operation location for the next phase of the project. The main test bench ASSIST and the 2nd Generation M2-Unit (hosting the Deformable Secondary Mirror) have been granted acceptance late 2012. The DSM will now undergo a series of tests on ASSIST to qualify its optical performance which launches the System Test Phase of the AOF. The tests will validate the AO modules operation with the DSM: first the GRAAL adaptive optics module for Hawk-I in natural guide star AO mode on-axis and then its Ground Layer AO mode. This will be followed by the GALACSI (for MUSE) Wide-Field-Mode (GLAO) and then the more challenging Narrow-Field-Mode (LTAO). We will report on the status of the subsystems at the time of the conference but also on the performance of the delivered ASSIST test bench, the DSM and the 20 Watt Sodium fiber Laser pre-production unit which has validated all specifications before final manufacturing of the serial units. We will also present some considerations and tools to ensure an efficient operation of the Facility in Paranal.

  6. Test Anxiety, Computer-Adaptive Testing and the Common Core

    ERIC Educational Resources Information Center

    Colwell, Nicole Makas

    2013-01-01

    This paper highlights the current findings and issues regarding the role of computer-adaptive testing in test anxiety. The computer-adaptive test (CAT) proposed by one of the Common Core consortia brings these issues to the forefront. Research has long indicated that test anxiety impairs student performance. More recent research indicates that…

  7. A Predictive Analysis Approach to Adaptive Testing.

    ERIC Educational Resources Information Center

    Kirisci, Levent; Hsu, Tse-Chi

    The predictive analysis approach to adaptive testing originated in the idea of statistical predictive analysis suggested by J. Aitchison and I.R. Dunsmore (1975). The adaptive testing model proposed is based on parameter-free predictive distribution. Aitchison and Dunsmore define statistical prediction analysis as the use of data obtained from an…

  8. Computerized Adaptive Testing under Nonparametric IRT Models

    ERIC Educational Resources Information Center

    Xu, Xueli; Douglas, Jeff

    2006-01-01

    Nonparametric item response models have been developed as alternatives to the relatively inflexible parametric item response models. An open question is whether it is possible and practical to administer computerized adaptive testing with nonparametric models. This paper explores the possibility of computerized adaptive testing when using…

  9. The Research on Computerized Adaptive Testing

    NASA Astrophysics Data System (ADS)

    Lu, Peng; Cong, Xiao

    2016-04-01

    In recent years, computerized adaptive testing is becoming the focus of the field of modern educational evaluation. In this form of the test, the response relationship between the examinee with the item by IRT modelling, then use the computer to estimates the ability level of the examinees and real-time select item. Computerized adaptive test development process were reviewed in the paper, and discuss the latest research results and pointed out that the current problems and future trends.

  10. Evaluating Content Alignment in Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Wise, Steven L.; Kingsbury, G. Gage; Webb, Norman L.

    2015-01-01

    The alignment between a test and the content domain it measures represents key evidence for the validation of test score inferences. Although procedures have been developed for evaluating the content alignment of linear tests, these procedures are not readily applicable to computerized adaptive tests (CATs), which require large item pools and do…

  11. Case Study: Test Results of a Tool and Method for In-Flight, Adaptive Control System Verification on a NASA F-15 Flight Research Aircraft

    NASA Technical Reports Server (NTRS)

    Jacklin, Stephen A.; Schumann, Johann; Guenther, Kurt; Bosworth, John

    2006-01-01

    Adaptive control technologies that incorporate learning algorithms have been proposed to enable autonomous flight control and to maintain vehicle performance in the face of unknown, changing, or poorly defined operating environments [1-2]. At the present time, however, it is unknown how adaptive algorithms can be routinely verified, validated, and certified for use in safety-critical applications. Rigorous methods for adaptive software verification end validation must be developed to ensure that. the control software functions as required and is highly safe and reliable. A large gap appears to exist between the point at which control system designers feel the verification process is complete, and when FAA certification officials agree it is complete. Certification of adaptive flight control software verification is complicated by the use of learning algorithms (e.g., neural networks) and degrees of system non-determinism. Of course, analytical efforts must be made in the verification process to place guarantees on learning algorithm stability, rate of convergence, and convergence accuracy. However, to satisfy FAA certification requirements, it must be demonstrated that the adaptive flight control system is also able to fail and still allow the aircraft to be flown safely or to land, while at the same time providing a means of crew notification of the (impending) failure. It was for this purpose that the NASA Ames Confidence Tool was developed [3]. This paper presents the Confidence Tool as a means of providing in-flight software assurance monitoring of an adaptive flight control system. The paper will present the data obtained from flight testing the tool on a specially modified F-15 aircraft designed to simulate loss of flight control faces.

  12. Graphical Models and Computerized Adaptive Testing.

    ERIC Educational Resources Information Center

    Almond, Russell G.; Mislevy, Robert J.

    1999-01-01

    Considers computerized adaptive testing from the perspective of graphical modeling (GM). GM provides methods for making inferences about multifaceted skills and knowledge and for extracting data from complex performances. Provides examples from language-proficiency assessment. (SLD)

  13. Adaptive structures - Test hardware and experimental results

    NASA Technical Reports Server (NTRS)

    Wada, Ben K.; Fanson, James L.; Chen, Gun-Shing; Kuo, Chin-Po

    1990-01-01

    The facilities and procedures used at JPL to test adaptive structures such as the large deployable reflector (LDR) are described and preliminary results are reported. The applications of adaptive structures in future NASA missions are outlined, and the techniques which are employed to modify damping, stiffness, and isolation characteristics, as well as geometric changes, are listed. The development of adaptive structures is shown to be effective as a result of new actuators and sensors, and examples are listed for categories such as fiber optics, shape-memory materials, piezoelectrics, and electrorheological fluids. Some ground test results are described for laboratory truss structures and truss test beds, which are shown to be efficient and easy to assemble in space. Adaptive structures are shown to be important for precision space structures such as the LDR, and can alleviate ground test requirements.

  14. Bayesian Item Selection in Constrained Adaptive Testing Using Shadow Tests

    ERIC Educational Resources Information Center

    Veldkamp, Bernard P.

    2010-01-01

    Application of Bayesian item selection criteria in computerized adaptive testing might result in improvement of bias and MSE of the ability estimates. The question remains how to apply Bayesian item selection criteria in the context of constrained adaptive testing, where large numbers of specifications have to be taken into account in the item…

  15. Adaptive wall testing sections (AWTS)

    NASA Technical Reports Server (NTRS)

    Wolf, Stephen W. D.; Kilgore, Robert A.

    1987-01-01

    The lecture starts with conventional techniques of minimizing wall interference and explains the principle of wall streamlining. The history of AWTS development is highlighted, along with the benefits of wall streamlining, including minimized boundary interference, increased model size, reduced tunnel drive power, noise, and volume, as well as multiple flow field simulations to be performed using one test section. AWTS-associated problems coming from the need to adjust the test-section boundaries for each test condition are assessed, along with the requirements of a boundary-adjustment strategy. Examples of two- and three-dimensional test sections are presented, and attention is focused on residual interference and the effects of compressibility and model lift on flexible-wall contours.

  16. An Introduction to the Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Tian, Jian-quan; Miao, Dan-min; Zhu, Xia; Gong, Jing-jing

    2007-01-01

    Computerized adaptive testing (CAT) has unsurpassable advantages over traditional testing. It has become the mainstream in large scale examinations in modern society. This paper gives a brief introduction to CAT including differences between traditional testing and CAT, the principles of CAT, psychometric theory and computer algorithms of CAT, the…

  17. Predictive Control of Speededness in Adaptive Testing

    ERIC Educational Resources Information Center

    van der Linden, Wim J.

    2009-01-01

    An adaptive testing method is presented that controls the speededness of a test using predictions of the test takers' response times on the candidate items in the pool. Two different types of predictions are investigated: posterior predictions given the actual response times on the items already administered and posterior predictions that use the…

  18. Engineering study for pallet adapting the Apollo laser altimeter and photographic camera system for the Lidar Test Experiment on orbital flight tests 2 and 4

    NASA Technical Reports Server (NTRS)

    Kuebert, E. J.

    1977-01-01

    A Laser Altimeter and Mapping Camera System was included in the Apollo Lunar Orbital Experiment Missions. The backup system, never used in the Apollo Program, is available for use in the Lidar Test Experiments on the STS Orbital Flight Tests 2 and 4. Studies were performed to assess the problem associated with installation and operation of the Mapping Camera System in the STS. They were conducted on the photographic capabilities of the Mapping Camera System, its mechanical and electrical interface with the STS, documentation, operation and survivability in the expected environments, ground support equipment, test and field support.

  19. Adaptive protection algorithm and system

    DOEpatents

    Hedrick, Paul [Pittsburgh, PA; Toms, Helen L [Irwin, PA; Miller, Roger M [Mars, PA

    2009-04-28

    An adaptive protection algorithm and system for protecting electrical distribution systems traces the flow of power through a distribution system, assigns a value (or rank) to each circuit breaker in the system and then determines the appropriate trip set points based on the assigned rank.

  20. Individual Differences in Computerized Adaptive Testing.

    ERIC Educational Resources Information Center

    Kim, JinGyu

    Research on the major computerized adaptive testing (CAT) strategies is reviewed, and some findings are reported that examine effects of examinee demographic and psychological characteristics on CAT strategies. In fixed branching strategies, all examinees respond to a common routing test, the score of which is used to assign examinees to a…

  1. Computerized Adaptive Testing with Item Cloning.

    ERIC Educational Resources Information Center

    Glas, Cees A. W.; van der Linden, Wim J.

    2003-01-01

    Developed a multilevel item response (IRT) model that allows for differences between the distributions of item parameters of families of item clones. Results from simulation studies based on an item pool from the Law School Admission Test illustrate the accuracy of the item pool calibration and adaptive testing procedures based on the model. (SLD)

  2. Quantitative Adaptation Analytics for Assessing Dynamic Systems of Systems.

    SciTech Connect

    Gauthier, John H.; Miner, Nadine E.; Wilson, Michael L.; Le, Hai D.; Kao, Gio K; Melander, Darryl J.; Longsine, Dennis Earl; Vander Meer, Robert Charles,

    2015-01-01

    Our society is increasingly reliant on systems and interoperating collections of systems, known as systems of systems (SoS). These SoS are often subject to changing missions (e.g., nation- building, arms-control treaties), threats (e.g., asymmetric warfare, terrorism), natural environments (e.g., climate, weather, natural disasters) and budgets. How well can SoS adapt to these types of dynamic conditions? This report details the results of a three year Laboratory Directed Research and Development (LDRD) project aimed at developing metrics and methodologies for quantifying the adaptability of systems and SoS. Work products include: derivation of a set of adaptability metrics, a method for combining the metrics into a system of systems adaptability index (SoSAI) used to compare adaptability of SoS designs, development of a prototype dynamic SoS (proto-dSoS) simulation environment which provides the ability to investigate the validity of the adaptability metric set, and two test cases that evaluate the usefulness of a subset of the adaptability metrics and SoSAI for distinguishing good from poor adaptability in a SoS. Intellectual property results include three patents pending: A Method For Quantifying Relative System Adaptability, Method for Evaluating System Performance, and A Method for Determining Systems Re-Tasking.

  3. Adaptive environment classification system for hearing aids.

    PubMed

    Lamarche, Luc; Giguère, Christian; Gueaieb, Wail; Aboulnasr, Tyseer; Othman, Hisham

    2010-05-01

    An adaptive sound classification framework is proposed for hearing aid applications. The long-term goal is to develop fully trainable instruments in which both the acoustical environments encountered in daily life and the hearing aid settings preferred by the user in each environmental class could be learned. Two adaptive classifiers are described, one based on minimum distance clustering and one on Bayesian classification. Through unsupervised learning, the adaptive systems allow classes to split or merge based on changes in the ongoing acoustical environments. Performance was evaluated using real-world sounds from a wide range of acoustical environments. The systems were first initialized using two classes, speech and noise, followed by a testing period when a third class, music, was introduced. Both systems were successful in detecting the presence of an additional class and estimating its underlying parameters, reaching a testing accuracy close to the target rates obtained from best-case scenarios derived from non-adaptive supervised versions of the classifiers (about 3% lower performance). The adaptive Bayesian classifier resulted in a 4% higher overall accuracy upon splitting adaptation than the minimum distance classifier. Merging accuracy was found to be the same in the two systems and within 1%-2% of the best-case supervised versions. PMID:21117761

  4. Flipping Adapters for Space Launch System

    NASA Video Gallery

    The structural test article adapter is flipped at Marshall testing facility Building 4705. The turnover is an important step in finishing the machining work on the adapter, which will undergo tests...

  5. Adaptive sequential testing for multiple comparisons.

    PubMed

    Gao, Ping; Liu, Lingyun; Mehta, Cyrus

    2014-01-01

    We propose a Markov process theory-based adaptive sequential testing procedure for multiple comparisons. The procedure can be used for confirmative trials involving multi-comparisons, including dose selection or population enrichment. Dose or subpopulation selection and sample size modification can be made at any interim analysis. Type I error control is exact. PMID:24926848

  6. Some Practical Examples of Computer-Adaptive Sequential Testing.

    ERIC Educational Resources Information Center

    Luecht, Richard M.; Nungester, Ronald J.

    1998-01-01

    Describes an integrated approach to test development and administration called computer-adaptive sequential testing (CAST). CAST incorporates adaptive testing methods with automated test assembly. Describes the CAST framework and demonstrates several applications using a medical-licensure example. (SLD)

  7. Constraining Item Exposure in Computerized Adaptive Testing with Shadow Tests

    ERIC Educational Resources Information Center

    van der Linden, Wim J.; Veldkamp, Bernard P.

    2004-01-01

    Item-exposure control in computerized adaptive testing is implemented by imposing item-ineligibility constraints on the assembly process of the shadow tests. The method resembles Sympson and Hetter's (1985) method of item-exposure control in that the decisions to impose the constraints are probabilistic. The method does not, however, require…

  8. Nanosatellite Launch Adapter System (NLAS)

    NASA Technical Reports Server (NTRS)

    Yost, Bruce D.; Hines, John W.; Agasid, Elwood F.; Buckley, Steven J.

    2010-01-01

    The utility of small spacecraft based on the University cubesat standard is becoming evident as more and more agencies and organizations are launching or planning to include nanosatellites in their mission portfolios. Cubesats are typically launched as secondary spacecraft in enclosed, containerized deployers such as the CalPoly Poly Picosat Orbital Deployer (P-POD) system. The P-POD allows for ease of integration and significantly reduces the risk exposure to the primary spacecraft and mission. NASA/ARC and the Operationally Responsive Space office are collaborating to develop a Nanosatellite Launch Adapter System (NLAS), which can accommodate multiple cubesat or cubesat-derived spacecraft on a single launch vehicle. NLAS is composed of the adapter structure, P-POD or similar spacecraft dispensers, and a sequencer/deployer system. This paper describes the NLAS system and it s future capabilities, and also provides status on the system s development and potential first use in space.

  9. Architecture for Adaptive Intelligent Systems

    NASA Technical Reports Server (NTRS)

    Hayes-Roth, Barbara

    1993-01-01

    We identify a class of niches to be occupied by 'adaptive intelligent systems (AISs)'. In contrast with niches occupied by typical AI agents, AIS niches present situations that vary dynamically along several key dimensions: different combinations of required tasks, different configurations of available resources, contextual conditions ranging from benign to stressful, and different performance criteria. We present a small class hierarchy of AIS niches that exhibit these dimensions of variability and describe a particular AIS niche, ICU (intensive care unit) patient monitoring, which we use for illustration throughout the paper. We have designed and implemented an agent architecture that supports all of different kinds of adaptation by exploiting a single underlying theoretical concept: An agent dynamically constructs explicit control plans to guide its choices among situation-triggered behaviors. We illustrate the architecture and its support for adaptation with examples from Guardian, an experimental agent for ICU monitoring.

  10. The Limits to Adaptation; A Systems Approach

    EPA Science Inventory

    The Limits to Adaptation: A Systems Approach. The ability to adapt to climate change is delineated by capacity thresholds, after which climate damages begin to overwhelm the adaptation response. Such thresholds depend upon physical properties (natural processes and engineering...

  11. An adaptive learning control system for aircraft

    NASA Technical Reports Server (NTRS)

    Mekel, R.; Nachmias, S.

    1976-01-01

    A learning control system is developed which blends the gain scheduling and adaptive control into a single learning system that has the advantages of both. An important feature of the developed learning control system is its capability to adjust the gain schedule in a prescribed manner to account for changing aircraft operating characteristics. Furthermore, if tests performed by the criteria of the learning system preclude any possible change in the gain schedule, then the overall system becomes an ordinary gain scheduling system. Examples are discussed.

  12. Final Report - Regulatory Considerations for Adaptive Systems

    NASA Technical Reports Server (NTRS)

    Wilkinson, Chris; Lynch, Jonathan; Bharadwaj, Raj

    2013-01-01

    This report documents the findings of a preliminary research study into new approaches to the software design assurance of adaptive systems. We suggest a methodology to overcome the software validation and verification difficulties posed by the underlying assumption of non-adaptive software in the requirementsbased- testing verification methods in RTCA/DO-178B and C. An analysis of the relevant RTCA/DO-178B and C objectives is presented showing the reasons for the difficulties that arise in showing satisfaction of the objectives and suggested additional means by which they could be satisfied. We suggest that the software design assurance problem for adaptive systems is principally one of developing correct and complete high level requirements and system level constraints that define the necessary system functional and safety properties to assure the safe use of adaptive systems. We show how analytical techniques such as model based design, mathematical modeling and formal or formal-like methods can be used to both validate the high level functional and safety requirements, establish necessary constraints and provide the verification evidence for the satisfaction of requirements and constraints that supplements conventional testing. Finally the report identifies the follow-on research topics needed to implement this methodology.

  13. A simplified adaptive optics system

    NASA Astrophysics Data System (ADS)

    Ivanescu, Liviu; Racine, René; Nadeau, Daniel

    2003-02-01

    Affordable adaptive optics on small telescopes allow to introduce the technology to a large community and provide opportunities to train new specialists in the field. We have developed a low order, low cost adaptive optics system for the 1.6m telescope of the Mont Megantic Observatory. The system corrects tip-tilt, focus, astigmatisms and one trefoil term. It explores a number of new approaches. The sensor receives a single out-of-focus image of the reference star. The central obstruction of the telescope can free the focus detection from the effect of seeing and allows a very small defocus. The deformable mirror is profiled so as to preserve a parabolic shape under pressure from actuators located at its edge. A separate piezoelectric platform drives the tilt mirror.

  14. Adapter assembly prevents damage to tubing during high pressure tests

    NASA Technical Reports Server (NTRS)

    Stinett, L. L.

    1965-01-01

    Portable adapter assembly prevents damage to tubing and injury to personnel when pressurizing a system or during high pressure tests. The assembly is capable of withstanding high pressure. It is securely attached to the tubing stub end and may be removed without brazing, cutting or cleaning the tube.

  15. A Multiple Objective Test Assembly Approach for Exposure Control Problems in Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Veldkamp, Bernard P.; Verschoor, Angela J.; Eggen, Theo J. H. M.

    2010-01-01

    Overexposure and underexposure of items in the bank are serious problems in operational computerized adaptive testing (CAT) systems. These exposure problems might result in item compromise, or point at a waste of investments. The exposure control problem can be viewed as a test assembly problem with multiple objectives. Information in the test has…

  16. Implementation and Use of Simulated Students for Test and Validation of New Adaptive Educational Systems: A Practical Insight

    ERIC Educational Resources Information Center

    Dorça, Fabiano

    2015-01-01

    Studies attest that learning is facilitated if teaching strategies are in accordance with students learning styles, making learning process more effective and considerably improving students performances. In this context, one major research point--and a challenge--is to efficiently discover students' learning styles. But, the test and validation…

  17. Certification Considerations for Adaptive Systems

    NASA Technical Reports Server (NTRS)

    Bhattacharyya, Siddhartha; Cofer, Darren; Musliner, David J.; Mueller, Joseph; Engstrom, Eric

    2015-01-01

    Advanced capabilities planned for the next generation of aircraft, including those that will operate within the Next Generation Air Transportation System (NextGen), will necessarily include complex new algorithms and non-traditional software elements. These aircraft will likely incorporate adaptive control algorithms that will provide enhanced safety, autonomy, and robustness during adverse conditions. Unmanned aircraft will operate alongside manned aircraft in the National Airspace (NAS), with intelligent software performing the high-level decision-making functions normally performed by human pilots. Even human-piloted aircraft will necessarily include more autonomy. However, there are serious barriers to the deployment of new capabilities, especially for those based upon software including adaptive control (AC) and artificial intelligence (AI) algorithms. Current civil aviation certification processes are based on the idea that the correct behavior of a system must be completely specified and verified prior to operation. This report by Rockwell Collins and SIFT documents our comprehensive study of the state of the art in intelligent and adaptive algorithms for the civil aviation domain, categorizing the approaches used and identifying gaps and challenges associated with certification of each approach.

  18. Adaptive Random Testing with Combinatorial Input Domain

    PubMed Central

    Lu, Yansheng

    2014-01-01

    Random testing (RT) is a fundamental testing technique to assess software reliability, by simply selecting test cases in a random manner from the whole input domain. As an enhancement of RT, adaptive random testing (ART) has better failure-detection capability and has been widely applied in different scenarios, such as numerical programs, some object-oriented programs, and mobile applications. However, not much work has been done on the effectiveness of ART for the programs with combinatorial input domain (i.e., the set of categorical data). To extend the ideas to the testing for combinatorial input domain, we have adopted different similarity measures that are widely used for categorical data in data mining and have proposed two similarity measures based on interaction coverage. Then, we propose a new version named ART-CID as an extension of ART in combinatorial input domain, which selects an element from categorical data as the next test case such that it has the lowest similarity against already generated test cases. Experimental results show that ART-CID generally performs better than RT, with respect to different evaluation metrics. PMID:24772036

  19. Adaptive output feedback control of flexible systems

    NASA Astrophysics Data System (ADS)

    Yang, Bong-Jun

    Neural network-based adaptive output feedback approaches that augment a linear control design are described in this thesis, and emphasis is placed on their real-time implementation with flexible systems. Two different control architectures that are robust to parametric uncertainties and unmodelled dynamics are presented. The unmodelled effects can consist of minimum phase internal dynamics of the system together with external disturbance process. Within this context, adaptive compensation for external disturbances is addressed. In the first approach, internal model-following control, adaptive elements are designed using feedback inversion. The effect of an actuator limit is treated using control hedging, and the effect of other actuation nonlinearities, such as dead zone and backlash, is mitigated by a disturbance observer-based control design. The effectiveness of the approach is illustrated through simulation and experimental testing with a three-disk torsional system, which is subjected to control voltage limit and stiction. While the internal model-following control is limited to minimum phase systems, the second approach, external model-following control, does not involve feedback linearization and can be applied to non-minimum phase systems. The unstable zero dynamics are assumed to have been modelled in the design of the existing linear controller. The laboratory tests for this method include a three-disk torsional pendulum, an inverted pendulum, and a flexible-base robot manipulator. The external model-following control architecture is further extended in three ways. The first extension is an approach for control of multivariable nonlinear systems. The second extension is a decentralized adaptive control approach for large-scale interconnected systems. The third extension is to make use of an adaptive observer to augment a linear observer-based controller. In this extension, augmenting terms for the adaptive observer can be used to achieve adaptation in

  20. Adaptive Behaviour Assessment System: Indigenous Australian Adaptation Model (ABAS: IAAM)

    ERIC Educational Resources Information Center

    du Plessis, Santie

    2015-01-01

    The study objectives were to develop, trial and evaluate a cross-cultural adaptation of the Adaptive Behavior Assessment System-Second Edition Teacher Form (ABAS-II TF) ages 5-21 for use with Indigenous Australian students ages 5-14. This study introduced a multiphase mixed-method design with semi-structured and informal interviews, school…

  1. ERIS adaptive optics system design

    NASA Astrophysics Data System (ADS)

    Marchetti, Enrico; Le Louarn, Miska; Soenke, Christian; Fedrigo, Enrico; Madec, Pierre-Yves; Hubin, Norbert

    2012-07-01

    The Enhanced Resolution Imager and Spectrograph (ERIS) is the next-generation instrument planned for the Very Large Telescope (VLT) and the Adaptive Optics facility (AOF). It is an AO assisted instrument that will make use of the Deformable Secondary Mirror and the new Laser Guide Star Facility (4LGSF), and it is planned for the Cassegrain focus of the telescope UT4. The project is currently in its Phase A awaiting for approval to continue to the next phases. The Adaptive Optics system of ERIS will include two wavefront sensors (WFS) to maximize the coverage of the proposed sciences cases. The first is a high order 40x40 Pyramid WFS (PWFS) for on axis Natural Guide Star (NGS) observations. The second is a high order 40x40 Shack-Hartmann WFS for single Laser Guide Stars (LGS) observations. The PWFS, with appropriate sub-aperture binning, will serve also as low order NGS WFS in support to the LGS mode with a field of view patrolling capability of 2 arcmin diameter. Both WFSs will be equipped with the very low read-out noise CCD220 based camera developed for the AOF. The real-time reconstruction and control is provided by a SPARTA real-time platform adapted to support both WFS modes. In this paper we will present the ERIS AO system in all its main aspects: opto-mechanical design, real-time computer design, control and calibrations strategy. Particular emphasis will be given to the system performance obtained via dedicated numerical simulations.

  2. The ERIS adaptive optics system

    NASA Astrophysics Data System (ADS)

    Marchetti, Enrico; Fedrigo, Enrico; Le Louarn, Miska; Madec, Pierre-Yves; Soenke, Christian; Brast, Roland; Conzelmann, Ralf; Delabre, Bernard; Duchateau, Michel; Frank, Christoph; Klein, Barbara; Amico, Paola; Hubin, Norbert; Esposito, Simone; Antichi, Jacopo; Carbonaro, Luca; Puglisi, Alfio; Quirós-Pacheco, Fernando; Riccardi, Armando; Xompero, Marco

    2014-07-01

    The Enhanced Resolution Imager and Spectrograph (ERIS) is the new Adaptive Optics based instrument for ESO's VLT aiming at replacing NACO and SINFONI to form a single compact facility with AO fed imaging and integral field unit spectroscopic scientific channels. ERIS completes the instrument suite at the VLT adaptive telescope. In particular it is equipped with a versatile AO system that delivers up to 95% Strehl correction in K band for science observations up to 5 micron It comprises high order NGS and LGS correction enabling the observation from exoplanets to distant galaxies with a large sky coverage thanks to the coupling of the LGS WFS with the high sensitivity of its visible WFS and the capability to observe in dust embedded environment thanks to its IR low order WFS. ERIS will be installed at the Cassegrain focus of the VLT unit hosting the Adaptive Optics Facility (AOF). The wavefront correction is provided by the AOF deformable secondary mirror while the Laser Guide Star is provided by one of the four launch units of the 4 Laser Guide Star Facility for the AOF. The overall layout of the ERIS AO system is extremely compact and highly optimized: the SPIFFI spectrograph is fed directly by the Cassegrain focus and both the NIX's (IR imager) and SPIFFI's entrance windows work as visible/infrared dichroics. In this paper we describe the concept of the ERIS AO system in detail, starting from the requirements and going through the estimated performance, the opto-mechanical design and the Real-Time Computer design.

  3. An adaptive association test for microbiome data.

    PubMed

    Wu, Chong; Chen, Jun; Kim, Junghi; Pan, Wei

    2016-01-01

    There is increasing interest in investigating how the compositions of microbial communities are associated with human health and disease. Although existing methods have identified many associations, a proper choice of a phylogenetic distance is critical for the power of these methods. To assess an overall association between the composition of a microbial community and an outcome of interest, we present a novel multivariate testing method called aMiSPU, that is joint and highly adaptive over all observed taxa and thus high powered across various scenarios, alleviating the issue with the choice of a phylogenetic distance. Our simulations and real-data analyses demonstrated that the aMiSPU test was often more powerful than several competing methods while correctly controlling type I error rates. The R package MiSPU is available at https://github.com/ChongWu-Biostat/MiSPU and CRAN. PMID:27198579

  4. Adaptive functional systems: Learning with chaos

    NASA Astrophysics Data System (ADS)

    Komarov, M. A.; Osipov, G. V.; Burtsev, M. S.

    2010-12-01

    We propose a new model of adaptive behavior that combines a winnerless competition principle and chaos to learn new functional systems. The model consists of a complex network of nonlinear dynamical elements producing sequences of goal-directed actions. Each element describes dynamics and activity of the functional system which is supposed to be a distributed set of interacting physiological elements such as nerve or muscle that cooperates to obtain certain goal at the level of the whole organism. During "normal" behavior, the dynamics of the system follows heteroclinic channels, but in the novel situation chaotic search is activated and a new channel leading to the target state is gradually created simulating the process of learning. The model was tested in single and multigoal environments and had demonstrated a good potential for generation of new adaptations.

  5. Adaptable state based control system

    NASA Technical Reports Server (NTRS)

    Rasmussen, Robert D. (Inventor); Dvorak, Daniel L. (Inventor); Gostelow, Kim P. (Inventor); Starbird, Thomas W. (Inventor); Gat, Erann (Inventor); Chien, Steve Ankuo (Inventor); Keller, Robert M. (Inventor)

    2004-01-01

    An autonomous controller, comprised of a state knowledge manager, a control executor, hardware proxies and a statistical estimator collaborates with a goal elaborator, with which it shares common models of the behavior of the system and the controller. The elaborator uses the common models to generate from temporally indeterminate sets of goals, executable goals to be executed by the controller. The controller may be updated to operate in a different system or environment than that for which it was originally designed by the replacement of shared statistical models and by the instantiation of a new set of state variable objects derived from a state variable class. The adaptation of the controller does not require substantial modification of the goal elaborator for its application to the new system or environment.

  6. Space Station Payload Adaptation System

    NASA Technical Reports Server (NTRS)

    Taylor, Kenneth R.; Adams, Charles L.

    1990-01-01

    The development and design of a system of containers for the efficient integration of Space Station payloads is described called the Space Station Payload Adaptation System (SSPAS). The SSPAS was developed to address the incorporation of multiple payloads, the use of a small payload carrier, large numbers of samples, and on-orbit servicing. SSPAS subsystems such as the Spacelab rack are modular and designed for integration into the 'Quick Is Beautiful' (QIB) facility. The QIB is designed to provide access to space for small- and medium-sized microgravity research projects and proof-of-concept investigations. The power-distribution and heat-rejection potential of the QIB are described, and an improved experiment-apparatus container is proposed. The SSPAS rack-mounting and container concepts are concluded to make up an efficent system that can effectively exploit the R&D potential of the Space Station.

  7. Nanosatellite Launch Adapter System (NLAS)

    NASA Technical Reports Server (NTRS)

    Chartres, James; Cappuccio, Gelsomina

    2015-01-01

    The Nanosatellite Launch Adapter System (NLAS) was developed to increase access to space while simplifying the integration process of miniature satellites, called nanosats or CubeSats, onto launch vehicles. A standard CubeSat measures about 10 cm square, and is referred to as a 1-unit (1U) CubeSat. A single NLAS provides the capability to deploy 24U of CubeSats. The system is designed to accommodate satellites measuring 1U, 1.5U, 2U, 3U and 6U sizes for deployment into orbit. The NLAS may be configured for use on different launch vehicles. The system also enables flight demonstrations of new technologies in the space environment.

  8. First closed-loop visible AO test results for the advanced adaptive secondary AO system for the Magellan Telescope: MagAO's performance and status

    NASA Astrophysics Data System (ADS)

    Close, Laird M.; Males, Jared R.; Kopon, Derek A.; Gasho, Victor; Follette, Katherine B.; Hinz, Phil; Morzinski, Katie; Uomoto, Alan; Hare, Tyson; Riccardi, Armando; Esposito, Simone; Puglisi, Alfio; Pinna, Enrico; Busoni, Lorenzo; Arcidiacono, Carmelo; Xompero, Marco; Briguglio, Runa; Quiros-Pacheco, Fernando; Argomedo, Javier

    2012-07-01

    The heart of the 6.5 Magellan AO system (MagAO) is a 585 actuator adaptive secondary mirror (ASM) with <1 msec response times (0.7 ms typically). This adaptive secondary will allow low emissivity and high-contrast AO science. We fabricated a high order (561 mode) pyramid wavefront sensor (similar to that now successfully used at the Large Binocular Telescope). The relatively high actuator count (and small projected ~23 cm pitch) allows moderate Strehls to be obtained by MagAO in the “visible” (0.63-1.05 μm). To take advantage of this we have fabricated an AO CCD science camera called "VisAO". Complete “end-to-end” closed-loop lab tests of MagAO achieve a solid, broad-band, 37% Strehl (122 nm rms) at 0.76 μm (i’) with the VisAO camera in 0.8” simulated seeing (13 cm ro at V) with fast 33 mph winds and a 40 m Lo locked on R=8 mag artificial star. These relatively high visible wavelength Strehls are enabled by our powerful combination of a next generation ASM and a Pyramid WFS with 400 controlled modes and 1000 Hz sample speeds (similar to that used successfully on-sky at the LBT). Currently only the VisAO science camera is used for lab testing of MagAO, but this high level of measured performance (122 nm rms) promises even higher Strehls with our IR science cameras. On bright (R=8 mag) stars we should achieve very high Strehls (>70% at H) in the IR with the existing MagAO Clio2 (λ=1-5.3 μm) science camera/coronagraph or even higher (~98% Strehl) the Mid-IR (8-26 microns) with the existing BLINC/MIRAC4 science camera in the future. To eliminate non-common path vibrations, dispersions, and optical errors the VisAO science camera is fed by a common path advanced triplet ADC and is piggy-backed on the Pyramid WFS optical board itself. Also a high-speed shutter can be used to block periods of poor correction. The entire system passed CDR in June 2009, and we finished the closed-loop system level testing phase in December 2011. Final system acceptance (

  9. Electricity Market Complex Adaptive System

    SciTech Connect

    2004-10-14

    EMCAS is a model developed for the simulation and analysis of electricity markets. As power markets are relatively new and still continue to evolve, there is a growing need for advanced modeling approaches that simulate the behavior of electricity markets over time and how market participants may act and react to the changing economic, financial, and regulatory environments in which they operate. A new and rather promising approach applied in the EMCAS software is to model the electricity market as a complex adaptive system using an agent-based modeling and simulation scheme. With its unique combination of various novel approaches, the Agent Based Modeling System (ABMS) provides the ability to capture and investigate the complex interactions between the physical infrastructures (generation, transmission, and distribution) and the economic behavior of market participants that are a trademark of the newly emerging markets.

  10. Electricity Market Complex Adaptive System

    2004-10-14

    EMCAS is a model developed for the simulation and analysis of electricity markets. As power markets are relatively new and still continue to evolve, there is a growing need for advanced modeling approaches that simulate the behavior of electricity markets over time and how market participants may act and react to the changing economic, financial, and regulatory environments in which they operate. A new and rather promising approach applied in the EMCAS software is tomore » model the electricity market as a complex adaptive system using an agent-based modeling and simulation scheme. With its unique combination of various novel approaches, the Agent Based Modeling System (ABMS) provides the ability to capture and investigate the complex interactions between the physical infrastructures (generation, transmission, and distribution) and the economic behavior of market participants that are a trademark of the newly emerging markets.« less

  11. Adaptive structures for precision controlled large space systems

    NASA Technical Reports Server (NTRS)

    Garba, John A.; Wada, Ben K.; Fanson, James L.

    1991-01-01

    The stringent accuracy and ground test validation requirements of some of the future space missions will require new approaches in structural design. Adaptive structures, structural systems that can vary their geometric congiguration as well as their physical properties, are primary candidates for meeting the functional requirements for such missions. Research performed in the development of such adaptive structural systems is described.

  12. The Adaptability Evaluation of Enterprise Information Systems

    NASA Astrophysics Data System (ADS)

    Liu, Junjuan; Xue, Chaogai; Dong, Lili

    In this paper, a set of evaluation system is proposed by GQM (Goal-Question-Metrics) for enterprise information systems. Then based on Similarity to Ideal Solution (TOPSIS), the evaluation model is proposed to evaluate enterprise information systems' adaptability. Finally, the application of the evaluation system and model is proved via a case study, which provides references for optimizing enterprise information systems' adaptability.

  13. Adaptive Embedded Digital System for Plasma Diagnostics

    NASA Astrophysics Data System (ADS)

    González, Angel; Rodríguez, Othoniel; Mangual, Osvaldo; Ponce, Eduardo; Vélez, Xavier

    2014-05-01

    An Adaptive Embedded Digital System to perform plasma diagnostics using electrostatic probes was developed at the Plasma Engineering Laboratory at Polytechnic University of Puerto Rico. The system will replace the existing instrumentation at the Laboratory, using reconfigurable hardware to minimize the equipment and software needed to perform diagnostics. The adaptability of the design resides on the possibility of replacing the computational algorithm on the fly, allowing to use the same hardware for different probes. The system was prototyped using Very High Speed Integrated Circuits Hardware Description Language (VHDL) into an Field Programmable Gate Array (FPGA) board. The design of the Embedded Digital System includes a Zero Phase Digital Filter, a Derivative Unit, and a Computational Unit designed using the VHDL-2008 Support Library. The prototype is able to compute the Plasma Electron Temperature and Density from a Single Langmuir probe. The system was tested using real data previously acquired from a single Langmuir probe. The plasma parameters obtained from the embedded system were compared with results computed using matlab yielding excellent matching. The new embedded system operates on 4096 samples versus 500 on the previous system, and completes its computations in 26 milliseconds compared with about 15 seconds on the previous system.

  14. "catR": An R Package for Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Magis, David; Raiche, Gilles

    2011-01-01

    Computerized adaptive testing (CAT) is an active current research field in psychometrics and educational measurement. However, there is very little software available to handle such adaptive tasks. The R package "catR" was developed to perform adaptive testing with as much flexibility as possible, in an attempt to provide a developmental and…

  15. High-resolution adaptive optics test bed for vision science

    NASA Astrophysics Data System (ADS)

    Wilks, Scott C.; Thompson, Charles A.; Olivier, Scot S.; Bauman, Brian J.; Flath, Laurence M.; Silva, Dennis A.; Sawvel, Robert M.; Barnes, Thomas B.; Werner, John S.

    2002-02-01

    We discuss the design and implementation of a low-cost, high-resolution adaptive optics test-bed for vision research. It is well known that high-order aberrations in the human eye reduce optical resolution and limit visual acuity. However, the effects of aberration-free eyesight on vision are only now beginning to be studied using adaptive optics to sense and correct the aberrations in the eye. We are developing a high-resolution adaptive optics system for this purpose using a Hamamatsu Parallel Aligned Nematic Liquid Crystal Spatial Light Modulator. Phase-wrapping is used to extend the effective stroke of the device, and the wavefront sensing and wavefront correction are done at different wavelengths. Issues associated with these techniques will be discussed.

  16. Implementing the Computer-Adaptive Sequential Testing (CAST) Framework To Mass Produce High Quality Computer-Adaptive and Mastery Tests.

    ERIC Educational Resources Information Center

    Luecht, Richard M.

    Computerized testing has created new challenges for the production and administration of test forms. This paper describes a multi-stage, testlet-based framework for test design, assembly, and administration called computer-adaptive sequential testing (CAST). CAST is a structured testing approach that is amenable to both adaptive and mastery…

  17. The Effects of Feedback in Computerized Adaptive and Self-Adapted Tests.

    ERIC Educational Resources Information Center

    Roos, Linda L.; And Others

    Computerized adaptive (CA) testing uses an algorithm to match examinee ability to item difficulty, while self-adapted (SA) testing allows the examinee to choose the difficulty of his or her items. Research comparing SA and CA testing has shown that examinees experience lower anxiety and improved performance with SA testing. All previous research…

  18. The Magellan Telescope adaptive secondary AO system

    NASA Astrophysics Data System (ADS)

    Close, Laird M.; Gasho, Victor; Kopon, Derek; Hinz, Phil M.; Hoffmann, William F.; Uomoto, Alan; Hare, Tyson

    2008-07-01

    The Magellan Clay telescope is a 6.5m Gregorian telescope located in southern Chile at Las Campanas Observatory. The Gregorian design allows for an adaptive secondary mirror that can be tested off-sky in a straight-forward manner. We have fabricated a 85 cm diameter aspheric adaptive secondary with our subcontractors and partners. This secondary has 585 actuators with <1 msec response times. The chopping adaptive secondary will allow low emissivity AO science. We will achieve very high Strehls (~98%) in the Mid-IR AO (8-26 microns) with the BLINC/MIRAC4 Mid-IR science camera. This will allow the first "super-resolution" and nulling Mid-IR studies of dusty southern objects. We will employ a high order (585 mode) pyramid wavefront sensor similar to that used in the Large Binocular Telescope AO systems. The relatively high actuator count will allow modest Strehls to be obtained in the visible (~0.8μm). Our visible light AO (Vis AO) science camera is fed by an advanced ADC and beamsplitter piggy-backed on the WFS optical table. The system science and performance requirements, and an overview the design, interface and schedule for the Magellan AO system are presented here.

  19. Indirect Adaptive Fuzzy Power System Stabilizer

    NASA Astrophysics Data System (ADS)

    Saoudi, Kamel; Bouchama, Ziad; Harmas, Mohamed Naguib; Zehar, Khaled

    2008-06-01

    A power system stabilizer based on adaptive fuzzy technique is presented. The design of a fuzzy logic power system stabilizer (FLPSS) requires the collection of fuzzy IF-THEN rules which are used to initialize an adaptive fuzzy power system AFPSS. The rule-base can be then tuned on-line so that the stabilizer can adapt to the different operating conditions occurring in the power system. The adaptation laws are developed based on a Lyapunov synthesis approach. Assessing the validity of this technique simulation of a power system is conducted and results are discussed.

  20. Intelligent test integration system

    NASA Technical Reports Server (NTRS)

    Sztipanovits, J.; Padalkar, S.; Rodriguez-Moscoso, J.; Kawamura, K.; Purves, B.; Williams, R.; Biglari, H.

    1988-01-01

    A new test technology is described which was developed for space system integration. The ultimate purpose of the system is to support the automatic generation of test systems in real time, distributed computing environments. The Intelligent Test Integration System (ITIS) is a knowledge based layer above the traditional test system components which can generate complex test configurations from the specification of test scenarios.

  1. Gaia as a complex adaptive system.

    PubMed Central

    Lenton, Timothy M; van Oijen, Marcel

    2002-01-01

    We define the Gaia system of life and its environment on Earth, review the status of the Gaia theory, introduce potentially relevant concepts from complexity theory, then try to apply them to Gaia. We consider whether Gaia is a complex adaptive system (CAS) in terms of its behaviour and suggest that the system is self-organizing but does not reside in a critical state. Gaia has supported abundant life for most of the last 3.8 Gyr. Large perturbations have occasionally suppressed life but the system has always recovered without losing the capacity for large-scale free energy capture and recycling of essential elements. To illustrate how complexity theory can help us understand the emergence of planetary-scale order, we present a simple cellular automata (CA) model of the imaginary planet Daisyworld. This exhibits emergent self-regulation as a consequence of feedback coupling between life and its environment. Local spatial interaction, which was absent from the original model, can destabilize the system by generating bifurcation regimes. Variation and natural selection tend to remove this instability. With mutation in the model system, it exhibits self-organizing adaptive behaviour in its response to forcing. We close by suggesting how artificial life ('Alife') techniques may enable more comprehensive feasibility tests of Gaia. PMID:12079529

  2. Development of HIDEC adaptive engine control systems

    NASA Technical Reports Server (NTRS)

    Landy, R. J.; Yonke, W. A.; Stewart, J. F.

    1986-01-01

    The purpose of NASA's Highly Integrated Digital Electronic Control (HIDEC) flight research program is the development of integrated flight propulsion control modes, and the evaluation of their benefits aboard an F-15 test aircraft. HIDEC program phases are discussed, with attention to the Adaptive Engine Control System (ADECS I); this involves the upgrading of PW1128 engines for operation at higher engine pressure ratios and the production of greater thrust. ADECS II will involve the development of a constant thrust mode which will significantly reduce turbine operating temperatures.

  3. Multidimensional Adaptive Testing with Optimal Design Criteria for Item Selection

    ERIC Educational Resources Information Center

    Mulder, Joris; van der Linden, Wim J.

    2009-01-01

    Several criteria from the optimal design literature are examined for use with item selection in multidimensional adaptive testing. In particular, it is examined what criteria are appropriate for adaptive testing in which all abilities are intentional, some should be considered as a nuisance, or the interest is in the testing of a composite of the…

  4. Adaptive systems research in the NASA

    NASA Technical Reports Server (NTRS)

    Montgomery, R.

    1973-01-01

    The past contributions of NASA to adaptive control technology are reviewed. The review places emphasis on aircraft applications although spacecraft and launch vehicle control applications are included. Particular emphasis is given to the adaptive control system used in the X-15 research aircraft. Problem areas that limited the realizable performance of this adaptive system are discussed. Current technological capabilities are used to extrapolate the present-day potential for adaptive flight control. Specifically, the potential created by use of the modern high-speed digital computer in flight control is discussed. Present plans for research in digital adaptive control systems for the NASA F8-C digital fly-by-wire program are presented. These plans are currently envisioned to include research in at least two types of adaptive controls, the system identification/on-line design type, and the model reference type.

  5. Adaptive optics for directly imaging planetary systems

    NASA Astrophysics Data System (ADS)

    Bailey, Vanessa Perry

    In this dissertation I present the results from five papers (including one in preparation) on giant planets, brown dwarfs, and their environments, as well as on the commissioning and optimization of the Adaptive Optics system for the Large Binocular Telescope Interferometer. The first three Chapters cover direct imaging results on several distantly-orbiting planets and brown dwarf companions. The boundary between giant planets and brown dwarf companions in wide orbits is a blurry one. In Chapter 2, I use 3--5 mum imaging of several brown dwarf companions, combined with mid-infrared photometry for each system to constrain the circum-substellar disks around the brown dwarfs. I then use this information to discuss limits on scattering events versus in situ formation. In Chapters 3 and 4, I present results from an adaptive optics imaging survey for giant planets, where the target stars were selected based on the properties of their circumstellar debris disks. Specifically, we targeted systems with debris disks whose SEDs indicated gaps, clearings, or truncations; these features may possibly be sculpted by planets. I discuss in detail one planet-mass companion discovered as part of this survey, HD 106906 b. At a projected separation of 650 AU and weighing in at 11 Jupiter masses, a companion such as this is not a common outcome of any planet or binary star formation model. In the remaining three Chapters, I discuss pre-commissioning, on-sky results, and planned work on the Large Binocular Telescope Interferometer Adaptive Optics system. Before construction of the LBT AO system was complete, I tested a prototype of LBTI's pyramid wavefront sensor unit at the MMT with synthetically-generated calibration files. I present the methodology and MMT on-sky tests in Chapter 5. In Chapter 6, I present the commissioned performance of LBTIAO. Optical imperfections within LBTI limited the quality of the science images, and I describe a simple method to use the adaptive optics system

  6. Failing Tests: Commentary on "Adapting Educational Measurement to the Demands of Test-Based Accountability"

    ERIC Educational Resources Information Center

    Thissen, David

    2015-01-01

    In "Adapting Educational Measurement to the Demands of Test-Based Accountability" Koretz takes the time-honored engineering approach to educational measurement, identifying specific problems with current practice and proposing minimal modifications of the system to alleviate those problems. In response to that article, David Thissen…

  7. Modeling Power Systems as Complex Adaptive Systems

    SciTech Connect

    Chassin, David P.; Malard, Joel M.; Posse, Christian; Gangopadhyaya, Asim; Lu, Ning; Katipamula, Srinivas; Mallow, J V.

    2004-12-30

    Physical analogs have shown considerable promise for understanding the behavior of complex adaptive systems, including macroeconomics, biological systems, social networks, and electric power markets. Many of today's most challenging technical and policy questions can be reduced to a distributed economic control problem. Indeed, economically based control of large-scale systems is founded on the conjecture that the price-based regulation (e.g., auctions, markets) results in an optimal allocation of resources and emergent optimal system control. This report explores the state-of-the-art physical analogs for understanding the behavior of some econophysical systems and deriving stable and robust control strategies for using them. We review and discuss applications of some analytic methods based on a thermodynamic metaphor, according to which the interplay between system entropy and conservation laws gives rise to intuitive and governing global properties of complex systems that cannot be otherwise understood. We apply these methods to the question of how power markets can be expected to behave under a variety of conditions.

  8. USING AN ADAPTER TO PERFORM THE CHALFANT-STYLE CONTAINMENT VESSEL PERIODIC MAINTENANCE LEAK RATE TEST

    SciTech Connect

    Loftin, B.; Abramczyk, G.; Trapp, D.

    2011-06-03

    Recently the Packaging Technology and Pressurized Systems (PT&PS) organization at the Savannah River National Laboratory was asked to develop an adapter for performing the leak-rate test of a Chalfant-style containment vessel. The PT&PS organization collaborated with designers at the Department of Energy's Pantex Plant to develop the adapter currently in use for performing the leak-rate testing on the containment vessels. This paper will give the history of leak-rate testing of the Chalfant-style containment vessels, discuss the design concept for the adapter, give an overview of the design, and will present results of the testing done using the adapter.

  9. Visual Cues for an Adaptive Expert System.

    ERIC Educational Resources Information Center

    Miller, Helen B.

    NCR (National Cash Register) Corporation is pursuing opportunities to make their point of sale (POS) terminals easy to use and easy to learn. To approach the goal of making the technology invisible to the user, NCR has developed an adaptive expert prototype system for a department store POS operation. The structure for the adaptive system, the…

  10. A Computerized Adaptive Edition of the Differential Aptitude Tests.

    ERIC Educational Resources Information Center

    McBride, James R.

    An overview of the development of a computerized version of the Differential Aptitude Tests (DAT) is presented. It describes the previously existing printed version of the DAT, design of the computerized adaptive edition, calibration of the test items for use in the computerized version, and two field studies that compared the Adaptive and…

  11. MCATL: A Language for Authoring Computerized Adaptive Tests.

    ERIC Educational Resources Information Center

    Vale, C. David

    The specification of a computerized adaptive test, like the specification of computer-assisted instruction, is easier and can be done by personnel who are not proficient in computer programming if an authoring language is provided. The Minnesota Computerized Adaptive Testing Language (MCATL) is an authoring language specifically designed for…

  12. Computerized Adaptive Personality Testing: A Review and Illustration With the MMPI-2 Computerized Adaptive Version.

    ERIC Educational Resources Information Center

    Forbey, Johnathan D.; Ben-Porath, Yossef S.

    2007-01-01

    Computerized adaptive testing in personality assessment can improve efficiency by significantly reducing the number of items administered to answer an assessment question. Two approaches have been explored for adaptive testing in computerized personality assessment: item response theory and the countdown method. In this article, the authors…

  13. Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS)

    NASA Technical Reports Server (NTRS)

    Masek, Jeffrey G.

    2006-01-01

    The Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS) project is creating a record of forest disturbance and regrowth for North America from the Landsat satellite record, in support of the carbon modeling activities. LEDAPS relies on the decadal Landsat GeoCover data set supplemented by dense image time series for selected locations. Imagery is first atmospherically corrected to surface reflectance, and then change detection algorithms are used to extract disturbance area, type, and frequency. Reuse of the MODIS Land processing system (MODAPS) architecture allows rapid throughput of over 2200 MSS, TM, and ETM+ scenes. Initial ("Beta") surface reflectance products are currently available for testing, and initial continental disturbance products will be available by the middle of 2006.

  14. Evaluating the Content Validity of Multistage-Adaptive Tests

    ERIC Educational Resources Information Center

    Crotts, Katrina; Sireci, Stephen G.; Zenisky, April

    2012-01-01

    Validity evidence based on test content is important for educational tests to demonstrate the degree to which they fulfill their purposes. Most content validity studies involve subject matter experts (SMEs) who rate items that comprise a test form. In computerized-adaptive testing, examinees take different sets of items and test "forms" do not…

  15. ESO adaptive optics facility progress and first laboratory test results

    NASA Astrophysics Data System (ADS)

    Arsenault, Robin; Madec, Pierre-Yves; Paufique, Jérome; La Penna, Paolo; Stroebele, Stefan; Vernet, Elise; Pirard, Jean-Francois; Hackenberg, Wolfgang; Kuntschner, Harald; Kolb, Johann; Muller, Nicolas; Garcia-Rissmann, Aurea; Le Louarn, Miska; Amico, Paola; Hubin, Norbert; Lizon, Jean-Louis; Ridings, Rob; Haguenauer, Pierre; Abad, Jose A.; Fischer, Gerhard; Heinz, Volker; Kiekebusch, Mario; Argomedo, Javier; Conzelmann, Ralf; Tordo, Sebastien; Donaldson, Rob; Soenke, Christian; Duhoux, Philippe; Fedrigo, Enrico; Delabre, Bernard; Jost, Andrea; Duchateau, Michel; Downing, Mark; Reyes Moreno, Javier; Manescau, Antonio; Bonaccini Calia, Domenico; Quattri, Marco; Dupuy, Christophe; Guidolin, Ivan M.; Comin, Mauro; Guzman, Ronald; Buzzoni, Bernard; Quentin, Jutta; Lewis, Steffan; Jolley, Paul; Kraus, Max; Pfrommer, Thomas; Biasi, Roberto; Gallieni, Daniele; Stuik, Remko; Kaenders, Wilhelm; Ernstberger, Bernhard; Friedenauer, Axel

    2014-07-01

    The Adaptive Optics Facility project is completing the integration of its systems at ESO Headquarters in Garching. The main test bench ASSIST and the 2nd Generation M2-Unit (hosting the Deformable Secondary Mirror) have been granted acceptance late 2012. The DSM has undergone a series of tests on ASSIST in 2013 which have validated its optical performance and launched the System Test Phase of the AOF. This has been followed by the performance evaluation of the GRAAL natural guide star mode on-axis and will continue in 2014 with its Ground Layer AO mode. The GALACSI module (for MUSE) Wide-Field-Mode (GLAO) and the more challenging Narrow-Field-Mode (LTAO) will then be tested. The AOF has also taken delivery of the second scientific thin shell mirror and the first 22 Watt Sodium laser Unit. We will report on the system tests status, the performances evaluated on the ASSIST bench and advancement of the 4Laser Guide Star Facility. We will also present the near future plans for commissioning on the telescope and some considerations on tools to ensure an efficient operation of the Facility in Paranal.

  16. Testing the Apodized Pupil Lyot Coronagraph on the Laboratory for Adaptive Optics Extreme Adaptive Optics Testbed

    NASA Astrophysics Data System (ADS)

    Thomas, Sandrine J.; Soummer, Rémi; Dillon, Daren; Macintosh, Bruce; Gavel, Donald; Sivaramakrishnan, Anand

    2011-10-01

    We present testbed results of the Apodized Pupil Lyot Coronagraph (APLC) at the Laboratory for Adaptive Optics (LAO). These results are part of the validation and tests of the coronagraph and of the Extreme Adaptive Optics (ExAO) for the Gemini Planet Imager (GPI). The apodizer component is manufactured with a halftone technique using black chrome microdots on glass. Testing this APLC (like any other coronagraph) requires extremely good wavefront correction, which is obtained to the 1 nm rms level using the microelectricalmechanical systems (MEMS) technology, on the ExAO visible testbed of the LAO at the University of Santa Cruz. We used an APLC coronagraph without central obstruction, both with a reference super-polished flat mirror and with the MEMS to obtain one of the first images of a dark zone in a coronagraphic image with classical adaptive optics using a MEMS deformable mirror (without involving dark hole algorithms). This was done as a complementary test to the GPI coronagraph testbed at American Museum of Natural History, which studied the coronagraph itself without wavefront correction. Because we needed a full aperture, the coronagraph design is very different from the GPI design. We also tested a coronagraph with central obstruction similar to that of GPI. We investigated the performance of the APLC coronagraph and more particularly the effect of the apodizer profile accuracy on the contrast. Finally, we compared the resulting contrast to predictions made with a wavefront propagation model of the testbed to understand the effects of phase and amplitude errors on the final contrast.

  17. TESTING THE APODIZED PUPIL LYOT CORONAGRAPH ON THE LABORATORY FOR ADAPTIVE OPTICS EXTREME ADAPTIVE OPTICS TESTBED

    SciTech Connect

    Thomas, Sandrine J.; Dillon, Daren; Gavel, Donald; Macintosh, Bruce; Sivaramakrishnan, Anand E-mail: dillon@ucolick.org E-mail: soummer@stsci.edu E-mail: anand@amnh.org

    2011-10-15

    We present testbed results of the Apodized Pupil Lyot Coronagraph (APLC) at the Laboratory for Adaptive Optics (LAO). These results are part of the validation and tests of the coronagraph and of the Extreme Adaptive Optics (ExAO) for the Gemini Planet Imager (GPI). The apodizer component is manufactured with a halftone technique using black chrome microdots on glass. Testing this APLC (like any other coronagraph) requires extremely good wavefront correction, which is obtained to the 1 nm rms level using the microelectricalmechanical systems (MEMS) technology, on the ExAO visible testbed of the LAO at the University of Santa Cruz. We used an APLC coronagraph without central obstruction, both with a reference super-polished flat mirror and with the MEMS to obtain one of the first images of a dark zone in a coronagraphic image with classical adaptive optics using a MEMS deformable mirror (without involving dark hole algorithms). This was done as a complementary test to the GPI coronagraph testbed at American Museum of Natural History, which studied the coronagraph itself without wavefront correction. Because we needed a full aperture, the coronagraph design is very different from the GPI design. We also tested a coronagraph with central obstruction similar to that of GPI. We investigated the performance of the APLC coronagraph and more particularly the effect of the apodizer profile accuracy on the contrast. Finally, we compared the resulting contrast to predictions made with a wavefront propagation model of the testbed to understand the effects of phase and amplitude errors on the final contrast.

  18. A Comparison of Testlet-Based Test Designs for Computerized Adaptive Testing.

    ERIC Educational Resources Information Center

    Schnipke, Deborah L.; Reese, Lynda M.

    Two-stage and multistage test designs provide a way of roughly adapting item difficulty to test-taker ability. All test takers take a parallel stage-one test, and, based on their scores, they are routed to tests of different difficulty levels in subsequent stages. These designs provide some of the benefits of standard computerized adaptive testing…

  19. Adaptation in CRISPR-Cas Systems.

    PubMed

    Sternberg, Samuel H; Richter, Hagen; Charpentier, Emmanuelle; Qimron, Udi

    2016-03-17

    Clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated (Cas) proteins constitute an adaptive immune system in prokaryotes. The system preserves memories of prior infections by integrating short segments of foreign DNA, termed spacers, into the CRISPR array in a process termed adaptation. During the past 3 years, significant progress has been made on the genetic requirements and molecular mechanisms of adaptation. Here we review these recent advances, with a focus on the experimental approaches that have been developed, the insights they generated, and a proposed mechanism for self- versus non-self-discrimination during the process of spacer selection. We further describe the regulation of adaptation and the protein players involved in this fascinating process that allows bacteria and archaea to harbor adaptive immunity. PMID:26949040

  20. Computerized Adaptive Testing, Anxiety Levels, and Gender Differences

    ERIC Educational Resources Information Center

    Fritts, Barbara E.; Marszalek, Jacob M.

    2010-01-01

    This study compares the amount of test anxiety experienced on a computerized adaptive test (CAT) to a paper-and-pencil test (P&P), as well as the state test anxiety experienced between males and females. Ninety-four middle school CAT examinees were compared to 65 middle school P&P examinees on their responses to the State-Trait Anxiety Inventory…

  1. An Automatic Online Calibration Design in Adaptive Testing

    ERIC Educational Resources Information Center

    Makransky, Guido; Glas, Cees A. W.

    2010-01-01

    An accurately calibrated item bank is essential for a valid computerized adaptive test. However, in some settings, such as occupational testing, there is limited access to test takers for calibration. As a result of the limited access to possible test takers, collecting data to accurately calibrate an item bank in an occupational setting is…

  2. Modern Sequential Analysis and Its Applications to Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Bartroff, Jay; Finkelman, Matthew; Lai, Tze Leung

    2008-01-01

    After a brief review of recent advances in sequential analysis involving sequential generalized likelihood ratio tests, we discuss their use in psychometric testing and extend the asymptotic optimality theory of these sequential tests to the case of sequentially generated experiments, of particular interest in computerized adaptive testing. We…

  3. Turkish Adaptation of Test of Pretended Play

    ERIC Educational Resources Information Center

    Aydin, Aydan

    2012-01-01

    The objective of present research is to conduct validity and reliability analysis of the verbal section of Test of Pretended Play that will measure pretended play behaviors of pre-school age children (3-6 years of age). Test of Pretended Play was first developed by Vicky Lewis and Jill Boucher in 1997. This test aimed to measure pretended play…

  4. Nanosatellite Launch Adapter System (NLAS) Overview

    NASA Technical Reports Server (NTRS)

    Chartres, James

    2015-01-01

    An overview of the Nanosatellite Launch Adapter System (NLAS) is provided that contains information on NLAS' objectives and relevance, structural components and position in the launch vehicle stack, and details on its three main components.

  5. Application of Sequential Interval Estimation to Adaptive Mastery Testing

    ERIC Educational Resources Information Center

    Chang, Yuan-chin Ivan

    2005-01-01

    In this paper, we apply sequential one-sided confidence interval estimation procedures with beta-protection to adaptive mastery testing. The procedures of fixed-width and fixed proportional accuracy confidence interval estimation can be viewed as extensions of one-sided confidence interval procedures. It can be shown that the adaptive mastery…

  6. A Sharing Item Response Theory Model for Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Segall, Daniel O.

    2004-01-01

    A new sharing item response theory (SIRT) model is presented that explicitly models the effects of sharing item content between informants and test takers. This model is used to construct adaptive item selection and scoring rules that provide increased precision and reduced score gains in instances where sharing occurs. The adaptive item selection…

  7. Computerized-Adaptive and Self-Adapted Music-Listening Tests: Psychometric Features and Motivational Benefits.

    ERIC Educational Resources Information Center

    Vispoel, Walter P.; Coffman, Don D.

    1994-01-01

    Computerized-adaptive (CAT) and self-adapted (SAT) music listening tests were compared for efficiency, reliability, validity, and motivational benefits with 53 junior high school students. Results demonstrate trade-offs, with greater potential motivational benefits for SAT and greater efficiency for CAT. SAT elicited more favorable responses from…

  8. Small scale adaptive optics experiment systems engineering

    NASA Technical Reports Server (NTRS)

    Boykin, William H.

    1993-01-01

    Assessment of the current technology relating to the laser power beaming system which in full scale is called the Beam Transmission Optical System (BTOS). Evaluation of system integration efforts are being conducted by the various government agencies and industry. Concepts are being developed for prototypes of adaptive optics for a BTOS.

  9. Adaptive, full-spectrum solar energy system

    DOEpatents

    Muhs, Jeffrey D.; Earl, Dennis D.

    2003-08-05

    An adaptive full spectrum solar energy system having at least one hybrid solar concentrator, at least one hybrid luminaire, at least one hybrid photobioreactor, and a light distribution system operably connected to each hybrid solar concentrator, each hybrid luminaire, and each hybrid photobioreactor. A lighting control system operates each component.

  10. Adaptive Dialogue Systems for Assistive Living Environments

    ERIC Educational Resources Information Center

    Papangelis, Alexandros

    2013-01-01

    Adaptive Dialogue Systems (ADS) are intelligent systems, able to interact with users via multiple modalities, such as speech, gestures, facial expressions and others. Such systems are able to make conversation with their users, usually on a specific, narrow topic. Assistive Living Environments are environments where the users are by definition not…

  11. Balancing Flexible Constraints and Measurement Precision in Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Moyer, Eric L.; Galindo, Jennifer L.; Dodd, Barbara G.

    2012-01-01

    Managing test specifications--both multiple nonstatistical constraints and flexibly defined constraints--has become an important part of designing item selection procedures for computerized adaptive tests (CATs) in achievement testing. This study compared the effectiveness of three procedures: constrained CAT, flexible modified constrained CAT,…

  12. Cross-Validation of the Computerized Adaptive Screening Test (CAST).

    ERIC Educational Resources Information Center

    Pliske, Rebecca M.; And Others

    The Computerized Adaptive Screening Test (CAST) was developed to provide an estimate at recruiting stations of prospects' Armed Forces Qualification Test (AFQT) scores. The CAST was designed to replace the paper-and-pencil Enlistment Screening Test (EST). The initial validation study of CAST indicated that CAST predicts AFQT at least as accurately…

  13. L(sub 1) Adaptive Control Design for NASA AirSTAR Flight Test Vehicle

    NASA Technical Reports Server (NTRS)

    Gregory, Irene M.; Cao, Chengyu; Hovakimyan, Naira; Zou, Xiaotian

    2009-01-01

    In this paper we present a new L(sub 1) adaptive control architecture that directly compensates for matched as well as unmatched system uncertainty. To evaluate the L(sub 1) adaptive controller, we take advantage of the flexible research environment with rapid prototyping and testing of control laws in the Airborne Subscale Transport Aircraft Research system at the NASA Langley Research Center. We apply the L(sub 1) adaptive control laws to the subscale turbine powered Generic Transport Model. The presented results are from a full nonlinear simulation of the Generic Transport Model and some preliminary pilot evaluations of the L(sub 1) adaptive control law.

  14. Adaptation of a-Stratified Method in Variable Length Computerized Adaptive Testing.

    ERIC Educational Resources Information Center

    Wen, Jian-Bing; Chang, Hua-Hua; Hau, Kit-Tai

    Test security has often been a problem in computerized adaptive testing (CAT) because the traditional wisdom of item selection overly exposes high discrimination items. The a-stratified (STR) design advocated by H. Chang and his collaborators, which uses items of less discrimination in earlier stages of testing, has been shown to be very…

  15. The Minnesota Adaptive Instructional System: An Intelligent CBI System.

    ERIC Educational Resources Information Center

    Tennyson, Robert D.; And Others

    1984-01-01

    Briefly reviews theoretical developments in adaptive instructional systems, defines six characteristics of intelligent computer-based management systems, and presents theory and research of Minnesota Adaptive Instructional System (MAIS). Generic programing codes for amount and sequence of instruction, instructional display time, and advisement…

  16. A Computer-Adaptive Vocabulary Test

    ERIC Educational Resources Information Center

    Molina, Maria Teresa Lopez-Mezquita

    2009-01-01

    Lexical competence is considered to be an essential step in the development and consolidation of a student's linguistic ability, and thus the reliable assessment of such competence turns out to be a fundamental aspect in this process. The design and construction of vocabulary tests has become an area of special interest, as it may provide teachers…

  17. Adaptive Control for Microgravity Vibration Isolation System

    NASA Technical Reports Server (NTRS)

    Yang, Bong-Jun; Calise, Anthony J.; Craig, James I.; Whorton, Mark S.

    2005-01-01

    Most active vibration isolation systems that try to a provide quiescent acceleration environment for space science experiments have utilized linear design methods. In this paper, we address adaptive control augmentation of an existing classical controller that employs a high-gain acceleration feedback together with a low-gain position feedback to center the isolated platform. The control design feature includes parametric and dynamic uncertainties because the hardware of the isolation system is built as a payload-level isolator, and the acceleration Sensor exhibits a significant bias. A neural network is incorporated to adaptively compensate for the system uncertainties, and a high-pass filter is introduced to mitigate the effect of the measurement bias. Simulations show that the adaptive control improves the performance of the existing acceleration controller and keep the level of the isolated platform deviation to that of the existing control system.

  18. Automation of assertion testing - Grid and adaptive techniques

    NASA Technical Reports Server (NTRS)

    Andrews, D. M.

    1985-01-01

    Assertions can be used to automate the process of testing software. Two methods for automating the generation of input test data are described in this paper. One method selects the input values of variables at regular intervals in a 'grid'. The other, adaptive testing, uses assertion violations as a measure of errors detected and generates new test cases based on test results. The important features of assertion testing are that: it can be used throughout the entire testing cycle; it provides automatic notification of error conditions; and it can be used with automatic input generation techniques which eliminate the subjectivity in choosing test data.

  19. Smart HIV testing system.

    PubMed

    El Kateeb, Ali; Law, Peter; Chan, King

    2005-06-01

    The quick HIV testing method called "MiraWell Rapid HIV Test" uses a specialized testing kit to determine whether an individual's blood is contaminated with the HIV virus or not. When a drop of blood is placed on the center of the testing kit, a simple pattern will appear in the middle of the kit to indicate the test status, i.e., positive or negative. This HIV test should be done in a small clinic or in a lab and the test must be conducted by a trained technician. A smart HIV testing system was developed through this research to eliminate the human error that is associated with the use of the quick HIV testing kits. Also, the smart HIV system will improve the testing productivity in comparison to those achieved by the trained technicians. In this research, we have developed a cost-effective system that analyzes the image produced by the HIV kits. We have used a System-On-Chip (SOC) design approach based on the Field Programmable Gate Array (FPGA) technology and the Xilinx Virtex SOC chip in building the system's prototype. The system used a CMOS digital camera to capture the image and an FPGA chip to process the captured image and send the testing results to the display unit. The system can be used in small clinics and pharmacies and eliminates the need for trained technicians. The system has been tested successfully and 98% of the tests were correct. PMID:16078623

  20. Adapting the Bilingual Aphasia Test to Rarotongan (Cook Islands Maori): Linguistic and clinical considerations.

    PubMed

    Amberber, Amanda Miller

    2011-06-01

    This article describes the adaptation of the Bilingual Aphasia Test (BAT) to the Rarotongan dialect of Cook Islands Maori, a Polynesian language spoken in the Cook Islands and expatriate communities. A brief linguistic sketch of Rarotongan is presented. As Rarotongan is characterised by a complex pronominal system, 'a' versus 'o' possession and optional topicalisation and focus constructions, particular issues arose in obtaining a rigorous adaptation of the BAT. Methods for ensuring effective adaptation across contrastive language pairs and sociocultural aspects of adapting the BAT to Rarotongan are discussed. Obtaining adaptations from several proficient bilingual consultants, comparing versions and group discussion to resolve discrepancies were used for this adaptation and are recommended. It is asserted that every individual has the right to receive accurate, detailed language assessment in each of their languages, irrespective of the languages spoken in the wider community. Further adaptations of the BAT will assist this to be achieved. PMID:21631310

  1. Design of the Dual Conjugate Adaptive Optics Test-bed

    NASA Astrophysics Data System (ADS)

    Sharf, Inna; Bell, K.; Crampton, D.; Fitzsimmons, J.; Herriot, Glen; Jolissaint, Laurent; Lee, B.; Richardson, H.; van der Kamp, D.; Veran, Jean-Pierre

    order to quantify the quality of the correction achieved with the DM's. A mini-wavescope, also supplied by AOA, will be part of the test-bed and is intended for use as an auxilliary tool for system calibration and identification. The foreoptics of the complete layout emulates a 32 cm, F/40 telescope, which itself was scaled down from an 8 meter telescope, while maintaining a 2' field of view. The foreoptics entrance beam diameter is 30 mm. The tip-tilt mirror procured from Ball Aerospace is placed at 0km in the foreoptics, before the deformable mirrors. A turbulence generator and a source simulator must be constructed for the test-bed since it is intended for use as a stand-alone research facility. Several concepts were considered for the turbulence generator: a holographic simulator, a spatial light modulator based on liquid-crystal technology, a phase plate based simulator and the hot-air turbulence generator. The latter was identified as the most suitable concept for our facility, after comparing the versatility, capabilities, and cost of the alternatives. The proposed design follows closely that developed by [Jolissaint, 2000] and aims to produce turbulence with Cn2 delta h ~ O (10-10) and D/r0 of approximately 8. With an appropriately designed fold of the beam, a single hot-air turbulator can be used to provide both turbulence layers for the beam. The source simulator will accommodate three guide stars with a fixed triangular geometry and a white science source that can be placed at an arbitrary location in the field of view. The guide stars can be located either at infinity to emulate NGS, or at 90 km to emulate sodium backscatter produced with lasers in a real adaptive optics system. Since the GS are held fixed above the turbulence, they can also be used to derive tip-tilt information, thus obviating the need for Natural Guide Stars. The dual-layer adaptive optics test-bed presented in this poster is expected to be fully operational by the middle of 2002. Parts

  2. Operational Results of an Adaptive SDI System.

    ERIC Educational Resources Information Center

    Sage, C. R.; Fitzwater, D. R.

    The Ames Laboratory SDI system requires a minimum of human intervention. The adaptability of the system provides two major contributions to information dissemination. (1) The user benefits proportionately from the amount of effort he expends in setting up his profile and the diligence in sending back responses. (2) The document input has only to…

  3. The adaptive control system of acetylene generator

    NASA Astrophysics Data System (ADS)

    Kovaliuk, D. O.; Kovaliuk, Oleg; Burlibay, Aron; Gromaszek, Konrad

    2015-12-01

    The method of acetylene production in acetylene generator was analyzed. It was found that impossible to provide the desired process characteristics by the PID-controller. The adaptive control system of acetylene generator was developed. The proposed system combines the classic controller and fuzzy subsystem for controller parameters tuning.

  4. Nemesis Autonomous Test System

    NASA Technical Reports Server (NTRS)

    Barltrop, Kevin J.; Lee, Cin-Young; Horvath, Gregory A,; Clement, Bradley J.

    2012-01-01

    A generalized framework has been developed for systems validation that can be applied to both traditional and autonomous systems. The framework consists of an automated test case generation and execution system called Nemesis that rapidly and thoroughly identifies flaws or vulnerabilities within a system. By applying genetic optimization and goal-seeking algorithms on the test equipment side, a "war game" is conducted between a system and its complementary nemesis. The end result of the war games is a collection of scenarios that reveals any undesirable behaviors of the system under test. The software provides a reusable framework to evolve test scenarios using genetic algorithms using an operation model of the system under test. It can automatically generate and execute test cases that reveal flaws in behaviorally complex systems. Genetic algorithms focus the exploration of tests on the set of test cases that most effectively reveals the flaws and vulnerabilities of the system under test. It leverages advances in state- and model-based engineering, which are essential in defining the behavior of autonomous systems. It also uses goal networks to describe test scenarios.

  5. Oral adaptation of the Trail Making Test: A practical review.

    PubMed

    Kaemmerer, Tobias; Riordan, Patrick

    2016-01-01

    Despite being one of the most widely used measures in clinical neuropsychology, the Trail Making Test is highly reliant on intact vision and motor functioning. Given that these capacities are often compromised in patients requiring neuropsychological evaluation, various authors have proposed methods for adapting the Trail Making Test for oral administration. To date, a number of administration and score transformation methods have been proposed. We reviewed the existing literature on oral adaptation of the Trail Making Test in order to provide recommendations for practicing clinicians wishing to use the measure, and to highlight directions for future research. PMID:27218477

  6. Adaptive System Modeling for Spacecraft Simulation

    NASA Technical Reports Server (NTRS)

    Thomas, Justin

    2011-01-01

    This invention introduces a methodology and associated software tools for automatically learning spacecraft system models without any assumptions regarding system behavior. Data stream mining techniques were used to learn models for critical portions of the International Space Station (ISS) Electrical Power System (EPS). Evaluation on historical ISS telemetry data shows that adaptive system modeling reduces simulation error anywhere from 50 to 90 percent over existing approaches. The purpose of the methodology is to outline how someone can create accurate system models from sensor (telemetry) data. The purpose of the software is to support the methodology. The software provides analysis tools to design the adaptive models. The software also provides the algorithms to initially build system models and continuously update them from the latest streaming sensor data. The main strengths are as follows: Creates accurate spacecraft system models without in-depth system knowledge or any assumptions about system behavior. Automatically updates/calibrates system models using the latest streaming sensor data. Creates device specific models that capture the exact behavior of devices of the same type. Adapts to evolving systems. Can reduce computational complexity (faster simulations).

  7. An adaptive interferometer for optical testing .

    NASA Astrophysics Data System (ADS)

    Pariani, G.; Colella, L.; Bertarelli, C.; Aliverti, M.; Riva, M.; Bianco, A.

    Interferometry is a well-established technique to test optical elements. However, its use is challenging in the case of free-form and aspheric elements, due to the lack of the reference optics. The proposed idea concerns the development of a versatile interferometer, where its reference arm is equipped with a reprogrammable Computer Generated Hologram. This principle takes advantage from our study on photochromic materials for optical applications, which shows a strong and reversible modulation of transparency in the visible region. The encoding of the desired hologram can be done off-line, or directly into the interferometer, and different patterns may be realized sequentially after the erasing of the previous hologram. We report on the present state of the research and on the future perspectives. skip=5pt

  8. Evolving Systems and Adaptive Key Component Control

    NASA Technical Reports Server (NTRS)

    Frost, Susan A.; Balas, Mark J.

    2009-01-01

    We propose a new framework called Evolving Systems to describe the self-assembly, or autonomous assembly, of actively controlled dynamical subsystems into an Evolved System with a higher purpose. An introduction to Evolving Systems and exploration of the essential topics of the control and stability properties of Evolving Systems is provided. This chapter defines a framework for Evolving Systems, develops theory and control solutions for fundamental characteristics of Evolving Systems, and provides illustrative examples of Evolving Systems and their control with adaptive key component controllers.

  9. Multidimensional Computerized Adaptive Testing for Indonesia Junior High School Biology

    ERIC Educational Resources Information Center

    Kuo, Bor-Chen; Daud, Muslem; Yang, Chih-Wei

    2015-01-01

    This paper describes a curriculum-based multidimensional computerized adaptive test that was developed for Indonesia junior high school Biology. In adherence to the Indonesian curriculum of different Biology dimensions, 300 items was constructed, and then tested to 2238 students. A multidimensional random coefficients multinomial logit model was…

  10. Deriving Stopping Rules for Multidimensional Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Wang, Chun; Chang, Hua-Hua; Boughton, Keith A.

    2013-01-01

    Multidimensional computerized adaptive testing (MCAT) is able to provide a vector of ability estimates for each examinee, which could be used to provide a more informative profile of an examinee's performance. The current literature on MCAT focuses on the fixed-length tests, which can generate less accurate results for those examinees whose…

  11. When Cognitive Diagnosis Meets Computerized Adaptive Testing: CD-CAT

    ERIC Educational Resources Information Center

    Cheng, Ying

    2009-01-01

    Computerized adaptive testing (CAT) is a mode of testing which enables more efficient and accurate recovery of one or more latent traits. Traditionally, CAT is built upon Item Response Theory (IRT) models that assume unidimensionality. However, the problem of how to build CAT upon latent class models (LCM) has not been investigated until recently,…

  12. Computerized Adaptive Testing: From Inquiry to Operation [Book Review].

    ERIC Educational Resources Information Center

    Gierl, Mark J.

    1998-01-01

    This book documents the research, development, and implementation efforts that allowed the U.S. Department of Defense to initiate the Computerized Adaptive Testing Armed Services Vocational Aptitude Battery Program for enlistment testing. Traces the history of this program over 30 years. (SLD)

  13. A Conditional Exposure Control Method for Multidimensional Adaptive Testing

    ERIC Educational Resources Information Center

    Finkelman, Matthew; Nering, Michael L.; Roussos, Louis A.

    2009-01-01

    In computerized adaptive testing (CAT), ensuring the security of test items is a crucial practical consideration. A common approach to reducing item theft is to define maximum item exposure rates, i.e., to limit the proportion of examinees to whom a given item can be administered. Numerous methods for controlling exposure rates have been proposed…

  14. Microcomputer Network for Computerized Adaptive Testing (CAT): Program Listing.

    ERIC Educational Resources Information Center

    Quan, Baldwin; And Others

    This program listing is a supplement to the Microcomputer Network for Computerized Adaptive Testing (CAT). The driver textfile program allows access to major subprograms of the CAT project. The test administration textfile program gives examinees a prescribed set of subtests. The parameter management textfile program establishes a file containing…

  15. Test Translation and Adaptation in Public Education in the USA.

    ERIC Educational Resources Information Center

    Stansfield, Charles W.

    2003-01-01

    Discusses theoretical and practical issues pertaining to translation or adaptation of educational assessments in the United States. These include the role of language proficiency and academic background in performance on standards-based achievement tests in different languages, factors affecting the decision to translate tests in different…

  16. Mutual Information Item Selection in Adaptive Classification Testing

    ERIC Educational Resources Information Center

    Weissman, Alexander

    2007-01-01

    A general approach for item selection in adaptive multiple-category classification tests is provided. The approach uses mutual information (MI), a special case of the Kullback-Leibler distance, or relative entropy. MI works efficiently with the sequential probability ratio test and alleviates the difficulties encountered with using other local-…

  17. Proceedings of the 1977 Computerized Adaptive Testing Conference.

    ERIC Educational Resources Information Center

    Weiss, David J., Ed.

    The 27 papers in this collection (26 of which were presented at the conference) are organized according to the eight topical sessions: (1) Improving Ability Measurement Using Different Item Formats, (2) Alternative Models for Adaptive Testing, (3) Psychological and Subgroup Effects, (4) Performance Testing by Interactive Simulation, (5)…

  18. Adaptive fuzzy system for 3-D vision

    NASA Technical Reports Server (NTRS)

    Mitra, Sunanda

    1993-01-01

    An adaptive fuzzy system using the concept of the Adaptive Resonance Theory (ART) type neural network architecture and incorporating fuzzy c-means (FCM) system equations for reclassification of cluster centers was developed. The Adaptive Fuzzy Leader Clustering (AFLC) architecture is a hybrid neural-fuzzy system which learns on-line in a stable and efficient manner. The system uses a control structure similar to that found in the Adaptive Resonance Theory (ART-1) network to identify the cluster centers initially. The initial classification of an input takes place in a two stage process; a simple competitive stage and a distance metric comparison stage. The cluster prototypes are then incrementally updated by relocating the centroid positions from Fuzzy c-Means (FCM) system equations for the centroids and the membership values. The operational characteristics of AFLC and the critical parameters involved in its operation are discussed. The performance of the AFLC algorithm is presented through application of the algorithm to the Anderson Iris data, and laser-luminescent fingerprint image data. The AFLC algorithm successfully classifies features extracted from real data, discrete or continuous, indicating the potential strength of this new clustering algorithm in analyzing complex data sets. The hybrid neuro-fuzzy AFLC algorithm will enhance analysis of a number of difficult recognition and control problems involved with Tethered Satellite Systems and on-orbit space shuttle attitude controller.

  19. An automated thermal vacuum test system for use in environmental testing of flight systems and components

    NASA Technical Reports Server (NTRS)

    Cleckner, Craig S.; Knutson, Jeffrey R.

    1991-01-01

    Unusual requirements for the Pressure Distribution/Air Data System (PD/ADS) transducer thermal vacuum testing led to the development of a conductively heated and cooled, fully automated, bell-jar test system. The system has proven to be easily adaptable for other tests and offers the advantages of quick turn-around and low operational cost.

  20. Ground test validation of large precision structure through adaptive structures

    NASA Technical Reports Server (NTRS)

    Wada, Ben K.

    1992-01-01

    Without novel ground validation test (GVT) approaches for such space structures as those contemplated for an orbiting optical interferometer, this and other NASA missions will be stillborn. One such approach may involve the integration of adaptive structures concepts into initial structural designs, in order to accommodate GVT, as well as to allow for redundancy and enhance mission reliability. Adaptive structures are noted to intrinsically relax GVT requirements.

  1. Robust adaptive transient damping in power systems

    SciTech Connect

    Pierre, D.A.; Sadighi, I.; Trudnowski, D.J.; Smith, J.R.; Nehrir, M.H. . Dept. of Electrical Engineering)

    1992-09-01

    This Volume 1 of the final report on RP2665-1 contains two parts. part 1 consists of the following: (1) a literature review of real-time parameter identification algorithms which may be used in self-tuning adaptive control; (2) a description of mathematical discrete-time models that are linear in the parameters and that are useful for self-tuning adaptive control; (3) detailed descriptions of several variations of recursive-least-squares algorithms (RLS algorithms) and a unified representation of some of these algorithms; (4) a new variation of RLS called Corrector Least Squares (CLS); (5) a set of practical issues that need to be addressed in the implementation of RLS-based algorithms; (6) a set of simulation examples that illustrate properties of the identification methods; and (7) appendices With FORTRAN listings of several identification codes. Part 2 of this volume addresses the problem of damping electromechanical oscillations in power systems using advanced control theory. Two control strategies are developed. Controllers are then applied to a power system as power system stabilizer (PSS) units. The primary strategy is a decentralized indirect adaptive control scheme where multiple self-tuning adaptive controllers are coordinated. This adaptive scheme is presented in a general format and the stabilizing properties are demonstrated using examples. Both the adaptive and the conventional strategies are applied to a 17-machine computer-simulated power system. PSS units are applied to four generators in the system. Detailed simulation results are presented that show the feasibility and properties of both control schemes. FORTRAN codes for the control simulations are given in appendices of Part 2, as also are FORTRAN codes for the Prony identification method.

  2. Adaptive synchronization and anticipatory dynamical systems

    NASA Astrophysics Data System (ADS)

    Yang, Ying-Jen; Chen, Chun-Chung; Lai, Pik-Yin; Chan, C. K.

    2015-09-01

    Many biological systems can sense periodical variations in a stimulus input and produce well-timed, anticipatory responses after the input is removed. Such systems show memory effects for retaining timing information in the stimulus and cannot be understood from traditional synchronization consideration of passive oscillatory systems. To understand this anticipatory phenomena, we consider oscillators built from excitable systems with the addition of an adaptive dynamics. With such systems, well-timed post-stimulus responses similar to those from experiments can be obtained. Furthermore, a well-known model of working memory is shown to possess similar anticipatory dynamics when the adaptive mechanism is identified with synaptic facilitation. The last finding suggests that this type of oscillator can be common in neuronal systems with plasticity.

  3. Estimating Skin Cancer Risk: Evaluating Mobile Computer-Adaptive Testing

    PubMed Central

    Djaja, Ngadiman; Janda, Monika; Olsen, Catherine M; Whiteman, David C

    2016-01-01

    Background Response burden is a major detriment to questionnaire completion rates. Computer adaptive testing may offer advantages over non-adaptive testing, including reduction of numbers of items required for precise measurement. Objective Our aim was to compare the efficiency of non-adaptive (NAT) and computer adaptive testing (CAT) facilitated by Partial Credit Model (PCM)-derived calibration to estimate skin cancer risk. Methods We used a random sample from a population-based Australian cohort study of skin cancer risk (N=43,794). All 30 items of the skin cancer risk scale were calibrated with the Rasch PCM. A total of 1000 cases generated following a normal distribution (mean [SD] 0 [1]) were simulated using three Rasch models with three fixed-item (dichotomous, rating scale, and partial credit) scenarios, respectively. We calculated the comparative efficiency and precision of CAT and NAT (shortening of questionnaire length and the count difference number ratio less than 5% using independent t tests). Results We found that use of CAT led to smaller person standard error of the estimated measure than NAT, with substantially higher efficiency but no loss of precision, reducing response burden by 48%, 66%, and 66% for dichotomous, Rating Scale Model, and PCM models, respectively. Conclusions CAT-based administrations of the skin cancer risk scale could substantially reduce participant burden without compromising measurement precision. A mobile computer adaptive test was developed to help people efficiently assess their skin cancer risk. PMID:26800642

  4. Collaborative Systems Testing

    ERIC Educational Resources Information Center

    Pocatilu, Paul; Ciurea, Cristian

    2009-01-01

    Collaborative systems are widely used today in various activity fields. Their complexity is high and the development involves numerous resources and costs. Testing collaborative systems has a very important role for the systems' success. In this paper we present taxonomy of collaborative systems. The collaborative systems are classified in many…

  5. Robust adaptive control of HVDC systems

    SciTech Connect

    Reeve, J.; Sultan, M. )

    1994-07-01

    The transient performance of an HVDC power system is highly dependent on the parameters of the current/voltage regulators of the converter controls. In order to better accommodate changes in system structure or dc operating conditions, this paper introduces a new adaptive control strategy. The advantages of automatic tuning for continuous fine tuning are combined with predetermined gain scheduling in order to achieve robustness for large disturbances. Examples are provided for a digitally simulated back-to-back dc system.

  6. Utilizing feedback in adaptive SAR ATR systems

    NASA Astrophysics Data System (ADS)

    Horsfield, Owen; Blacknell, David

    2009-05-01

    Existing SAR ATR systems are usually trained off-line with samples of target imagery or CAD models, prior to conducting a mission. If the training data is not representative of mission conditions, then poor performance may result. In addition, it is difficult to acquire suitable training data for the many target types of interest. The Adaptive SAR ATR Problem Set (AdaptSAPS) program provides a MATLAB framework and image database for developing systems that adapt to mission conditions, meaning less reliance on accurate training data. A key function of an adaptive system is the ability to utilise truth feedback to improve performance, and it is this feature which AdaptSAPS is intended to exploit. This paper presents a new method for SAR ATR that does not use training data, based on supervised learning. This is achieved by using feature-based classification, and several new shadow features have been developed for this purpose. These features allow discrimination of vehicles from clutter, and classification of vehicles into two classes: targets, comprising military combat types, and non-targets, comprising bulldozers and trucks. The performance of the system is assessed using three baseline missions provided with AdaptSAPS, as well as three additional missions. All performance metrics indicate a distinct learning trend over the course of a mission, with most third and fourth quartile performance levels exceeding 85% correct classification. It has been demonstrated that these performance levels can be maintained even when truth feedback rates are reduced by up to 55% over the course of a mission.

  7. Adapting ISA system warnings to enhance user acceptance.

    PubMed

    Jiménez, Felipe; Liang, Yingzhen; Aparicio, Francisco

    2012-09-01

    Inappropriate speed is a major cause of traffic accidents. Different measures have been considered to control traffic speed, and intelligent speed adaptation (ISA) systems are one of the alternatives. These systems know the speed limits and try to improve compliance with them. This paper deals with an informative ISA system that provides the driver with an advance warning before reaching a road section with singular characteristics that require a lower safe speed than the current speed. In spite of the extensive tests performed using ISA systems, few works show how warnings can be adapted to the driver. This paper describes a method to adapt warning parameters (safe speed on curves, zone of influence of a singular stretch, deceleration process and reaction time) to normal driving behavior. The method is based on a set of tests with and without the ISA system. This adjustment, as well as the analysis of driver acceptance before and after the adaptation and changes in driver behavior (changes in speed and path) resulting from the tested ISA regarding a driver's normal driving style, is shown in this paper. The main conclusion is that acceptance by drivers increased significantly after redefining the warning parameters, but the effect of speed homogenization was not reduced. PMID:22664666

  8. Adaptive multisatellite systems for aeronautical services.

    NASA Technical Reports Server (NTRS)

    Bisaga, J. J.; Redisch, W. N.

    1971-01-01

    The use of satellite systems to provide operational communications and ATC services to aircraft flying the oceanic routes has been the subject of considerable interest recently. Since most of the link factors are functions of geometry and the aircraft traffic density varies with time, the satellite power needed to meet the communication demand varies considerably in an oceanic area as a function of both location and time. An adaptive system that tailors the use of system resources to the needs of the user can result in an additional system capacity improvement by a factor of between two and three. Results of studies conducted to date indicate that simple implementation of adaptive techniques in aeronautical satellite systems is feasible. Study is continuing in this area and on the application of satellite multibeam techniques to gain even further increase in capacity.

  9. Flight Test of an L(sub 1) Adaptive Controller on the NASA AirSTAR Flight Test Vehicle

    NASA Technical Reports Server (NTRS)

    Gregory, Irene M.; Xargay, Enric; Cao, Chengyu; Hovakimyan, Naira

    2010-01-01

    This paper presents results of a flight test of the L-1 adaptive control architecture designed to directly compensate for significant uncertain cross-coupling in nonlinear systems. The flight test was conducted on the subscale turbine powered Generic Transport Model that is an integral part of the Airborne Subscale Transport Aircraft Research system at the NASA Langley Research Center. The results presented are for piloted tasks performed during the flight test.

  10. Petascale IO Using The Adaptable IO System

    SciTech Connect

    Lofstead, J.; Klasky, Scott A; Abbasi, H.

    2009-01-01

    ADIOS, the adaptable IO system, has demonstrated excellent scalability to 29,000 cores. With the introduction of the XT5 upgrades to Jaguar, new optimizations are required to successfully reach 140,000+ cores. This paper explains the techniques employed and shows the performance levels attained.

  11. The Elements Of Adaptive Neural Expert Systems

    NASA Astrophysics Data System (ADS)

    Healy, Michael J.

    1989-03-01

    The generalization properties of a class of neural architectures can be modelled mathematically. The model is a parallel predicate calculus based on pattern recognition and self-organization of long-term memory in a neural network. It may provide the basis for adaptive expert systems capable of inductive learning and rapid processing in a highly complex and changing environment.

  12. Adaptive control system for gas producing wells

    SciTech Connect

    Fedor, Pashchenko; Sergey, Gulyaev; Alexander, Pashchenko

    2015-03-10

    Optimal adaptive automatic control system for gas producing wells cluster is proposed intended for solving the problem of stabilization of the output gas pressure in the cluster at conditions of changing gas flow rate and changing parameters of the wells themselves, providing the maximum high resource of hardware elements of automation.

  13. Polytomous Adaptive Classification Testing: Effects of Item Pool Size, Test Termination Criterion, and Number of Cutscores

    ERIC Educational Resources Information Center

    Gnambs, Timo; Batinic, Bernad

    2011-01-01

    Computer-adaptive classification tests focus on classifying respondents in different proficiency groups (e.g., for pass/fail decisions). To date, adaptive classification testing has been dominated by research on dichotomous response formats and classifications in two groups. This article extends this line of research to polytomous classification…

  14. Use of adaptive walls in 2D tests

    NASA Technical Reports Server (NTRS)

    Archambaud, J. P.; Chevallier, J. P.

    1984-01-01

    A new method for computing the wall effects gives precise answers to some questions arising in adaptive wall concept applications: length of adapted regions, fairings with up and downstream regions, residual misadjustments effects, reference conditions. The acceleration of the iterative process convergence and the development of an efficient technology used in CERT T2 wind tunnels give in a single run the required test conditions. Samples taken from CAST 7 tests demonstrate the efficiency of the whole process to obtain significant results with considerations of tridimensional case extension.

  15. Model reference adaptive systems some examples.

    NASA Technical Reports Server (NTRS)

    Landau, I. D.; Sinner, E.; Courtiol, B.

    1972-01-01

    A direct design method is derived for several single-input single-output model reference adaptive systems (M.R.A.S.). The approach used helps to clarify the various steps involved in a design, which utilizes the hyperstability concept. An example of a multiinput, multioutput M.R.A.S. is also discussed. Attention is given to the problem of a series compensator. It is pointed out that a series compensator which contains derivative terms must generally be introduced in the adaptation mechanism in order to assure asymptotic hyperstability. Results obtained by the simulation of a M.R.A.S. on an analog computer are also presented.

  16. Adaptive hybrid system for automatic sleep staging.

    PubMed

    Hassaan, Amr A; Morsy, Ahmed A

    2008-01-01

    We present a new adaptive system for automated sleep staging. The proposed system relies on each subject's own data for self-training. Conventional automatic sleep staging algorithms are either rule based, which typically fail to accurately model the complex nature of sleep signals, or numerical methods that use multi-patient training schemes, which suffer from inaccuracies caused by inherent inter-patient variability. The proposed system employs two stages. The first stage is a rule based reasoning engine that can be tuned conservatively to decrease or eliminate false positives, generating just enough samples to train the second stage, which is comprised of a neural network classifier. Results show that this hybrid approach provides an adaptive training scheme that performs more accurately compared to one of the popular commercially available systems. PMID:19162989

  17. An adaptive brain actuated system for augmenting rehabilitation

    PubMed Central

    Roset, Scott A.; Gant, Katie; Prasad, Abhishek; Sanchez, Justin C.

    2014-01-01

    For people living with paralysis, restoration of hand function remains the top priority because it leads to independence and improvement in quality of life. In approaches to restore hand and arm function, a goal is to better engage voluntary control and counteract maladaptive brain reorganization that results from non-use. Standard rehabilitation augmented with developments from the study of brain-computer interfaces could provide a combined therapy approach for motor cortex rehabilitation and to alleviate motor impairments. In this paper, an adaptive brain-computer interface system intended for application to control a functional electrical stimulation (FES) device is developed as an experimental test bed for augmenting rehabilitation with a brain-computer interface. The system's performance is improved throughout rehabilitation by passive user feedback and reinforcement learning. By continuously adapting to the user's brain activity, similar adaptive systems could be used to support clinical brain-computer interface neurorehabilitation over multiple days. PMID:25565945

  18. Adaptable Transponder for Multiple Telemetry Systems

    NASA Technical Reports Server (NTRS)

    Sims, William Herbert, III (Inventor); Varnavas, Kosta A. (Inventor)

    2014-01-01

    The present invention is a stackable telemetry circuit board for use in telemetry systems for satellites and other purposes. The present invention incorporates previously-qualified interchangeable circuit boards, or "decks," that perform functions such as power, signal receiving and transmission, and processing. Each deck is adapted to serve a range of telemetry applications. This provides flexibility in the construction of the stackable telemetry circuit board and significantly reduces the cost and time necessary to develop a telemetry system.

  19. Flash evaporator systems test

    NASA Technical Reports Server (NTRS)

    Dietz, J. B.

    1976-01-01

    A flash evaporator heat rejection system representative of that proposed for the space shuttle orbiter underwent extensive system testing at the NASA Johnson Space Center (JSC) to determine its operational suitability and to establish system performance/operational characteristics for use in the shuttle system. During the tests the evaporator system demonstrated its suitability to meet the shuttle requirements by: (1) efficient operation with 90 to 95% water evaporation efficiency, (2) control of outlet temperature to 40 + or - 2 F for partial heat load operation, (3) stability of control system for rapid changes in Freon inlet temperature, and (4) repeated dormant-to-active device operation without any startup procedures.

  20. The Influence of Examinee Test-Taking Motivation in Computerized Adaptive Testing.

    ERIC Educational Resources Information Center

    Kim, JinGyu; McLean, James E.

    The purpose of the study was to investigate the effects of test motivation on estimated ability, test anxiety, and attitudes toward computerized adaptive testing (CAT). Korean college students (n=208) were given the Math Aptitude Test, Math Self-Concept Scale, Math Test Anxiety Scale, Computer Competence Instrument, Computer Anxiety Scale, and…

  1. Adaptive Learning Resources Sequencing in Educational Hypermedia Systems

    ERIC Educational Resources Information Center

    Karampiperis, Pythagoras; Sampson, Demetrios

    2005-01-01

    Adaptive learning resources selection and sequencing is recognized as among the most interesting research questions in adaptive educational hypermedia systems (AEHS). In order to adaptively select and sequence learning resources in AEHS, the definition of adaptation rules contained in the Adaptation Model, is required. Although, some efforts have…

  2. Nanomechanical testing system

    DOEpatents

    Vodnick, David James; Dwivedi, Arpit; Keranen, Lucas Paul; Okerlund, Michael David; Schmitz, Roger William; Warren, Oden Lee; Young, Christopher David

    2014-07-08

    An automated testing system includes systems and methods to facilitate inline production testing of samples at a micro (multiple microns) or less scale with a mechanical testing instrument. In an example, the system includes a probe changing assembly for coupling and decoupling a probe of the instrument. The probe changing assembly includes a probe change unit configured to grasp one of a plurality of probes in a probe magazine and couple one of the probes with an instrument probe receptacle. An actuator is coupled with the probe change unit, and the actuator is configured to move and align the probe change unit with the probe magazine and the instrument probe receptacle. In another example, the automated testing system includes a multiple degree of freedom stage for aligning a sample testing location with the instrument. The stage includes a sample stage and a stage actuator assembly including translational and rotational actuators.

  3. Nanomechanical testing system

    SciTech Connect

    Vodnick, David James; Dwivedi, Arpit; Keranen, Lucas Paul; Okerlund, Michael David; Schmitz, Roger William; Warren, Oden Lee; Young, Christopher David

    2015-01-27

    An automated testing system includes systems and methods to facilitate inline production testing of samples at a micro (multiple microns) or less scale with a mechanical testing instrument. In an example, the system includes a probe changing assembly for coupling and decoupling a probe of the instrument. The probe changing assembly includes a probe change unit configured to grasp one of a plurality of probes in a probe magazine and couple one of the probes with an instrument probe receptacle. An actuator is coupled with the probe change unit, and the actuator is configured to move and align the probe change unit with the probe magazine and the instrument probe receptacle. In another example, the automated testing system includes a multiple degree of freedom stage for aligning a sample testing location with the instrument. The stage includes a sample stage and a stage actuator assembly including translational and rotational actuators.

  4. Nanomechanical testing system

    SciTech Connect

    Vodnick, David James; Dwivedi, Arpit; Keranen, Lucas Paul; Okerlund, Michael David; Schmitz, Roger William; Warren, Oden Lee; Young, Christopher David

    2015-02-24

    An automated testing system includes systems and methods to facilitate inline production testing of samples at a micro (multiple microns) or less scale with a mechanical testing instrument. In an example, the system includes a probe changing assembly for coupling and decoupling a probe of the instrument. The probe changing assembly includes a probe change unit configured to grasp one of a plurality of probes in a probe magazine and couple one of the probes with an instrument probe receptacle. An actuator is coupled with the probe change unit, and the actuator is configured to move and align the probe change unit with the probe magazine and the instrument probe receptacle. In another example, the automated testing system includes a multiple degree of freedom stage for aligning a sample testing location with the instrument. The stage includes a sample stage and a stage actuator assembly including translational and rotational actuators.

  5. Flight Test of Composite Model Reference Adaptive Control (CMRAC) Augmentation Using NASA AirSTAR Infrastructure

    NASA Technical Reports Server (NTRS)

    Gregory, Irene M.; Gadient, ROss; Lavretsky, Eugene

    2011-01-01

    This paper presents flight test results of a robust linear baseline controller with and without composite adaptive control augmentation. The flight testing was conducted using the NASA Generic Transport Model as part of the Airborne Subscale Transport Aircraft Research system at NASA Langley Research Center.

  6. Flexilevel Adaptive Testing Paradigm: Hierarchical Concept Structures. Final Report for Period May 1975-March 1977.

    ERIC Educational Resources Information Center

    Hansen, Duncan N.; And Others

    A computerized adaptive testing model was applied to a hierarchically arranged series of subtests within the instructional context of a technical education system. The model was a modification of Lord's flexilevel paradigm; however, it did not allow for individualized entry. Two achievement tests, each divided into five hierarchically related…

  7. Development of adaptive helicopter seat systems for aircrew vibration mitigation

    NASA Astrophysics Data System (ADS)

    Chen, Yong; Wickramasinghe, Viresh; Zimcik, David G.

    2008-03-01

    Helicopter aircrews are exposed to high levels of whole body vibration during flight. This paper presents the results of an investigation of adaptive seat mount approaches to reduce helicopter aircrew whole body vibration levels. A flight test was conducted on a four-blade helicopter and showed that the currently used passive seat systems were not able to provide satisfactory protection to the helicopter aircrew in both front-back and vertical directions. Long-term exposure to the measured whole body vibration environment may cause occupational health issues such as spine and neck strain injuries for aircrew. In order to address this issue, a novel adaptive seat mount concept was developed to mitigate the vibration levels transmitted to the aircrew body. For proof-of-concept demonstration, a miniature modal shaker was properly aligned between the cabin floor and the seat frame to provide adaptive actuation authority. Adaptive control laws were developed to reduce the vibration transmitted to the aircrew body, especially the helmet location in order to minimize neck and spine injuries. Closed-loop control test have been conducted on a full-scale helicopter seat with a mannequin configuration and a large mechanical shaker was used to provide representative helicopter vibration profiles to the seat frame. Significant vibration reductions to the vertical and front-back vibration modes have been achieved simultaneously, which verified the technical readiness of the adaptive mount approach for full-scale flight test on the vehicle.

  8. The Nominal Response Model in Computerized Adaptive Testing.

    ERIC Educational Resources Information Center

    De Ayala, R. J.

    One important and promising application of item response theory (IRT) is computerized adaptive testing (CAT). The implementation of a nominal response model-based CAT (NRCAT) was studied. Item pool characteristics for the NRCAT as well as the comparative performance of the NRCAT and a CAT based on the three-parameter logistic (3PL) model were…

  9. Multiple Maximum Exposure Rates in Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Ramon Barrada, Juan; Veldkamp, Bernard P.; Olea, Julio

    2009-01-01

    Computerized adaptive testing is subject to security problems, as the item bank content remains operative over long periods and administration time is flexible for examinees. Spreading the content of a part of the item bank could lead to an overestimation of the examinees' trait level. The most common way of reducing this risk is to impose a…

  10. Brazilian Adaptation of the Woodcock-Johnson III Cognitive Tests

    ERIC Educational Resources Information Center

    Wechsler, Solange Muglia; Nunes, Carlos Sancineto; Schelini, Patricia Waltz; Pasian, Sonia Regina; Homsi, Silvia Vertoni; Moretti, Lucia; Anache, Alexandra Ayach

    2010-01-01

    An adaptation of the standard battery of Woodcock-Johnson III Tests of Cognitive Abilities (WJ-III) for Brazilian children and youth was investigated. The sample was composed of 1094 students (54 percent girls), ages 7-17, living in Sao Paulo state (91 percent). Items from Brazilian school books as well as from the WJ-III Spanish version…

  11. A Monte Carlo Approach for Adaptive Testing with Content Constraints

    ERIC Educational Resources Information Center

    Belov, Dmitry I.; Armstrong, Ronald D.; Weissman, Alexander

    2008-01-01

    This article presents a new algorithm for computerized adaptive testing (CAT) when content constraints are present. The algorithm is based on shadow CAT methodology to meet content constraints but applies Monte Carlo methods and provides the following advantages over shadow CAT: (a) lower maximum item exposure rates, (b) higher utilization of the…

  12. A Framework for the Development of Computerized Adaptive Tests

    ERIC Educational Resources Information Center

    Thompson, Nathan A.; Weiss, David J.

    2011-01-01

    A substantial amount of research has been conducted over the past 40 years on technical aspects of computerized adaptive testing (CAT), such as item selection algorithms, item exposure controls, and termination criteria. However, there is little literature providing practical guidance on the development of a CAT. This paper seeks to collate some…

  13. 21. DREDGING POND USED TO TEST THE ADAPTABILITY OF JET ...

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

    21. DREDGING POND USED TO TEST THE ADAPTABILITY OF JET PUMPS FOR PUMPING SAND, AND WEAR RATES OF DIFFERENT TYPES OF DREDGING PIPE. - Waterways Experiment Station, Hydraulics Laboratory, Halls Ferry Road, 2 miles south of I-20, Vicksburg, Warren County, MS

  14. Multistage Computerized Adaptive Testing with Uniform Item Exposure

    ERIC Educational Resources Information Center

    Edwards, Michael C.; Flora, David B.; Thissen, David

    2012-01-01

    This article describes a computerized adaptive test (CAT) based on the uniform item exposure multi-form structure (uMFS). The uMFS is a specialization of the multi-form structure (MFS) idea described by Armstrong, Jones, Berliner, and Pashley (1998). In an MFS CAT, the examinee first responds to a small fixed block of items. The items comprising…

  15. Computerized Adaptive Testing with Multiple-Form Structures

    ERIC Educational Resources Information Center

    Armstrong, Ronald D.; Jones, Douglas H.; Koppel, Nicole B.; Pashley, Peter J.

    2004-01-01

    A multiple-form structure (MFS) is an ordered collection or network of testlets (i.e., sets of items). An examinee's progression through the network of testlets is dictated by the correctness of an examinee's answers, thereby adapting the test to his or her trait level. The collection of paths through the network yields the set of all possible…

  16. Using Response Times for Item Selection in Adaptive Testing

    ERIC Educational Resources Information Center

    van der Linden, Wim J.

    2008-01-01

    Response times on items can be used to improve item selection in adaptive testing provided that a probabilistic model for their distribution is available. In this research, the author used a hierarchical modeling framework with separate first-level models for the responses and response times and a second-level model for the distribution of the…

  17. Application of the Bifactor Model to Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Seo, Dong Gi

    2011-01-01

    Most computerized adaptive tests (CAT) have been studied under the framework of unidimensional item response theory. However, many psychological variables are multidimensional and might benefit from using a multidimensional approach to CAT. In addition, a number of psychological variables (e.g., quality of life, depression) can be conceptualized…

  18. L(sub 1) Adaptive Flight Control System: Flight Evaluation and Technology Transition

    NASA Technical Reports Server (NTRS)

    Xargay, Enric; Hovakimyan, Naira; Dobrokhodov, Vladimir; Kaminer, Isaac; Gregory, Irene M.; Cao, Chengyu

    2010-01-01

    Certification of adaptive control technologies for both manned and unmanned aircraft represent a major challenge for current Verification and Validation techniques. A (missing) key step towards flight certification of adaptive flight control systems is the definition and development of analysis tools and methods to support Verification and Validation for nonlinear systems, similar to the procedures currently used for linear systems. In this paper, we describe and demonstrate the advantages of L(sub l) adaptive control architectures for closing some of the gaps in certification of adaptive flight control systems, which may facilitate the transition of adaptive control into military and commercial aerospace applications. As illustrative examples, we present the results of a piloted simulation evaluation on the NASA AirSTAR flight test vehicle, and results of an extensive flight test program conducted by the Naval Postgraduate School to demonstrate the advantages of L(sub l) adaptive control as a verifiable robust adaptive flight control system.

  19. Innovations in dynamic test restraint systems

    NASA Technical Reports Server (NTRS)

    Fuld, Christopher J.

    1990-01-01

    Recent launch system development programs have led to a new generation of large scale dynamic tests. The variety of test scenarios share one common requirement: restrain and capture massive high velocity flight hardware with no structural damage. The Space Systems Lab of McDonnell Douglas developed a remarkably simple and cost effective approach to such testing using ripstitch energy absorbers adapted from the sport of technical rockclimbing. The proven system reliability of the capture system concept has led to a wide variety of applications in test system design and in aerospace hardware design.

  20. Adaptive Optics Imaging of Solar System Objects

    NASA Technical Reports Server (NTRS)

    Roddier, Francois; Owen, Toby

    1999-01-01

    Most solar system objects have never been observed at wavelengths longer than the R band with an angular resolution better than 1". The Hubble Space Telescope itself has only recently been equipped to observe in the infrared. However, because of its small diameter, the angular resolution is lower than that one can now achieved from the ground with adaptive optics, and time allocated to planetary science is limited. We have successfully used adaptive optics on a 4-m class telescope to obtain 0.1" resolution images of solar system objects in the far red and near infrared (0.7-2.5 microns), aE wavelengths which best discl"lmlnate their spectral signatures. Our efforts have been put into areas of research for which high angular resolution is essential.

  1. Adaptive Optics Imaging of Solar System Objects

    NASA Technical Reports Server (NTRS)

    Roddier, Francois; Owen, Toby

    1997-01-01

    Most solar system objects have never been observed at wavelengths longer than the R band with an angular resolution better than 1 sec. The Hubble Space Telescope itself has only recently been equipped to observe in the infrared. However, because of its small diameter, the angular resolution is lower than that one can now achieved from the ground with adaptive optics, and time allocated to planetary science is limited. We have been using adaptive optics (AO) on a 4-m class telescope to obtain 0.1 sec resolution images solar system objects at far red and near infrared wavelengths (0.7-2.5 micron) which best discriminate their spectral signatures. Our efforts has been put into areas of research for which high angular resolution is essential, such as the mapping of Titan and of large asteroids, the dynamics and composition of Neptune stratospheric clouds, the infrared photometry of Pluto, Charon, and close satellites previously undetected from the ground.

  2. Demonstration of portable solar adaptive optics system

    NASA Astrophysics Data System (ADS)

    Ren, Deqing; Dong, Bing

    2012-10-01

    Solar-adaptive optics (AO) are more challenging than night-time AO, in some aspects. A portable solar adaptive optics (PSAO) system featuring compact physical size, low cost, and good performance has been proposed and developed. PSAO can serve as a visiting instrument for any existing ground-based solar telescope to improve solar image quality by replacing just a few optical components. High-level programming language, LabVIEW, is used to develop the wavefront sensing and control software, and general purpose computers are used to drive the whole system. During October 2011, the feasibility and good performance of PSAO was demonstrated with the 61-cm solar telescope at San Fernando Observatory. The image contrast and resolution are noticeably improved after AO correction.

  3. Automated Testing System

    2006-05-09

    ATS is a Python-language program for automating test suites for software programs that do not interact with thier users, such as scripted scientific simulations. ATS features a decentralized approach especially suited to larger projects. In its multinode mode it can utilize many nodes of a cluster in order to do many test in parallel. It has features for submitting longer-running tests to a batch system and would have to be customized for use elsewhere.

  4. A Procedure for Controlling General Test Overlap in Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Chen, Shu-Ying

    2010-01-01

    To date, exposure control procedures that are designed to control test overlap in computerized adaptive tests (CATs) are based on the assumption of item sharing between pairs of examinees. However, in practice, examinees may obtain test information from more than one previous test taker. This larger scope of information sharing needs to be…

  5. Direct adaptive control for nonlinear uncertain dynamical systems

    NASA Astrophysics Data System (ADS)

    Hayakawa, Tomohisa

    In light of the complex and highly uncertain nature of dynamical systems requiring controls, it is not surprising that reliable system models for many high performance engineering and life science applications are unavailable. In the face of such high levels of system uncertainty, robust controllers may unnecessarily sacrifice system performance whereas adaptive controllers are clearly appropriate since they can tolerate far greater system uncertainty levels to improve system performance. In this dissertation, we develop a Lyapunov-based direct adaptive and neural adaptive control framework that addresses parametric uncertainty, unstructured uncertainty, disturbance rejection, amplitude and rate saturation constraints, and digital implementation issues. Specifically, we consider the following research topics; direct adaptive control for nonlinear uncertain systems with exogenous disturbances; robust adaptive control for nonlinear uncertain systems; adaptive control for nonlinear uncertain systems with actuator amplitude and rate saturation constraints; adaptive reduced-order dynamic compensation for nonlinear uncertain systems; direct adaptive control for nonlinear matrix second-order dynamical systems with state-dependent uncertainty; adaptive control for nonnegative and compartmental dynamical systems with applications to general anesthesia; direct adaptive control of nonnegative and compartmental dynamical systems with time delay; adaptive control for nonlinear nonnegative and compartmental dynamical systems with applications to clinical pharmacology; neural network adaptive control for nonlinear nonnegative dynamical systems; passivity-based neural network adaptive output feedback control for nonlinear nonnegative dynamical systems; neural network adaptive dynamic output feedback control for nonlinear nonnegative systems using tapped delay memory units; Lyapunov-based adaptive control framework for discrete-time nonlinear systems with exogenous disturbances

  6. Adaptable radiation monitoring system and method

    DOEpatents

    Archer, Daniel E.; Beauchamp, Brock R.; Mauger, G. Joseph; Nelson, Karl E.; Mercer, Michael B.; Pletcher, David C.; Riot, Vincent J.; Schek, James L.; Knapp, David A.

    2006-06-20

    A portable radioactive-material detection system capable of detecting radioactive sources moving at high speeds. The system has at least one radiation detector capable of detecting gamma-radiation and coupled to an MCA capable of collecting spectral data in very small time bins of less than about 150 msec. A computer processor is connected to the MCA for determining from the spectral data if a triggering event has occurred. Spectral data is stored on a data storage device, and a power source supplies power to the detection system. Various configurations of the detection system may be adaptably arranged for various radiation detection scenarios. In a preferred embodiment, the computer processor operates as a server which receives spectral data from other networked detection systems, and communicates the collected data to a central data reporting system.

  7. Optical Disk Testing System

    NASA Astrophysics Data System (ADS)

    Manns, Basil H.

    1987-01-01

    This paper describes the development of the basics of an optical disk testing system used to test 12 inch, write once, Alcatel Thomson Gigadisk (ATG) media that are used at the Library of Congress in a pilot document storage and retrieval system. Since very little is known regarding the longevity of optical disk media and the fact that disk manufacturers are still refining processing techniques, any conclusions regarding error patterns, failure modes, or longevity may be superceded by a new "batch" of disks. Therefore, this paper focuses on the development of procedures for testing disks that can be used as the write once optical disk technology continues to advance.

  8. An adaptive technique for a redundant-sensor navigation system.

    NASA Technical Reports Server (NTRS)

    Chien, T.-T.

    1972-01-01

    An on-line adaptive technique is developed to provide a self-contained redundant-sensor navigation system with a capability to utilize its full potentiality in reliability and performance. This adaptive system is structured as a multistage stochastic process of detection, identification, and compensation. It is shown that the detection system can be effectively constructed on the basis of a design value, specified by mission requirements, of the unknown parameter in the actual system, and of a degradation mode in the form of a constant bias jump. A suboptimal detection system on the basis of Wald's sequential analysis is developed using the concept of information value and information feedback. The developed system is easily implemented, and demonstrates a performance remarkably close to that of the optimal nonlinear detection system. An invariant transformation is derived to eliminate the effect of nuisance parameters such that the ambiguous identification system can be reduced to a set of disjoint simple hypotheses tests. By application of a technique of decoupled bias estimation in the compensation system the adaptive system can be operated without any complicated reorganization.

  9. An adaptive neuro-control system of synchronous generator for power system stabilization

    SciTech Connect

    Kobayashi, Takenori; Yokoyama, Akihiko

    1996-09-01

    This paper proposes a nonlinear adaptive generator control system using neural networks, called an adaptive neuro-control system (ANCS). This system generates supplementary control signals to conventional controllers and works adaptively in response to changes in operating conditions and network configuration. Through digital time simulations for a one-machine infinite bus test power system, the control performance of the ANCS and advanced controllers such as a linear optimal regulator and a self-tuning regulator is evaluated from the viewpoint of stability enhancement. As a result, the proposed ANCS using neural networks with nonlinear characteristics improves system damping more effectively and more adaptively than the other two controllers designed for the linearized model of the power system.

  10. Material Fatigue Testing System

    NASA Technical Reports Server (NTRS)

    Gilley, P. J. (Inventor)

    1973-01-01

    A system for cyclicly applying a varying load to a material under test is described. It includes a load sensor which senses the magnitude of load being applied to a material, and, upon sensing a selected magnitude of loading, causes the load to be maintained for a predetermined time and then cause the system to resume cyclical loading.

  11. Systems integration of innate and adaptive immunity.

    PubMed

    Zak, Daniel E; Aderem, Alan

    2015-09-29

    The pathogens causing AIDS, malaria, and tuberculosis have proven too complex to be overcome by classical approaches to vaccination. The complexities of human immunology and pathogen-induced modulation of the immune system mandate new approaches to vaccine discovery and design. A new field, systems vaccinology, weds holistic analysis of innate and adaptive immunity within a quantitative framework to enable rational design of new vaccines that elicit tailored protective immune responses. A key step in the approach is to discover relationships between the earliest innate inflammatory responses to vaccination and the subsequent vaccine-induced adaptive immune responses and efficacy. Analysis of these responses in clinical studies is complicated by the inaccessibility of relevant tissue compartments (such as the lymph node), necessitating reliance upon peripheral blood responses as surrogates. Blood transcriptomes, although indirect to vaccine mechanisms, have proven very informative in systems vaccinology studies. The approach is most powerful when innate and adaptive immune responses are integrated with vaccine efficacy, which is possible for malaria with the advent of a robust human challenge model. This is more difficult for AIDS and tuberculosis, given that human challenge models are lacking and efficacy observed in clinical trials has been low or highly variable. This challenge can be met by appropriate clinical trial design for partially efficacious vaccines and by analysis of natural infection cohorts. Ultimately, systems vaccinology is an iterative approach in which mechanistic hypotheses-derived from analysis of clinical studies-are evaluated in model systems, and then used to guide the development of new vaccine strategies. In this review, we will illustrate the above facets of the systems vaccinology approach with case studies. PMID:26102534

  12. A self-adaptive energy harvesting system

    NASA Astrophysics Data System (ADS)

    Hoffmann, D.; Willmann, A.; Hehn, T.; Folkmer, B.; Manoli, Y.

    2016-03-01

    This paper reports on a self-adaptive energy harvesting system, which is able to adapt its eigenfrequency to the operating conditions of power units. The power required for frequency tuning is delivered by the energy harvester itself. The tuning mechanism is based on a magnetic concept and incorporates a circular tuning magnet and a coupling magnet. In this manner, both coupling modes (attractive and repulsive) can be utilized for tuning the eigenfrequency of the energy harvester. The tuning range and its center frequency can be tailored to the application by careful design of the spring stiffness and the gap between tuning magnet and coupling magnet. Experimental results demonstrate that, in contrast to a conventional non-tunable vibration energy harvester, the net power can be significantly increased if a self-adaptive system is utilized, although additional power is required for regular adjustments of the eigenfrequency. The outcome confirms that active tuning is a real and practical option to extend the operational frequency range and to increase the net power of a conventional vibration energy harvester.

  13. Complex Adaptive Systems of Systems (CASOS) engineering environment.

    SciTech Connect

    Detry, Richard Joseph; Linebarger, John Michael; Finley, Patrick D.; Maffitt, S. Louise; Glass, Robert John, Jr.; Beyeler, Walter Eugene; Ames, Arlo Leroy

    2012-02-01

    Complex Adaptive Systems of Systems, or CASoS, are vastly complex physical-socio-technical systems which we must understand to design a secure future for the nation. The Phoenix initiative implements CASoS Engineering principles combining the bottom up Complex Systems and Complex Adaptive Systems view with the top down Systems Engineering and System-of-Systems view. CASoS Engineering theory and practice must be conducted together to develop a discipline that is grounded in reality, extends our understanding of how CASoS behave and allows us to better control the outcomes. The pull of applications (real world problems) is critical to this effort, as is the articulation of a CASoS Engineering Framework that grounds an engineering approach in the theory of complex adaptive systems of systems. Successful application of the CASoS Engineering Framework requires modeling, simulation and analysis (MS and A) capabilities and the cultivation of a CASoS Engineering Community of Practice through knowledge sharing and facilitation. The CASoS Engineering Environment, itself a complex adaptive system of systems, constitutes the two platforms that provide these capabilities.

  14. Contingency support using adaptive telemetry extractor and expert system technologies

    NASA Technical Reports Server (NTRS)

    Bryant, Thomas; Cruse, Bryant; Wende, Charles

    1987-01-01

    The 'telemetry analysis logic for operations support' prototype system constitutes an expert system that is charged with contingency planning for the NASA Hubble Space Telescope (HST); this system has demonstrated the feasibility of using an adaptive telemetry extractor/reformatter that is integrated with an expert system. A test case generated by a simulator has demonstrated the reduction of the time required for analysis of a complex series of failures to a few minutes, from the hour usually required. The HST's telemetry extractor will be able to read real-time engineering telemetry streams and disk-based data. Telemetry format changes will be handled almost instantaneously.

  15. Social networks as embedded complex adaptive systems.

    PubMed

    Benham-Hutchins, Marge; Clancy, Thomas R

    2010-09-01

    As systems evolve over time, their natural tendency is to become increasingly more complex. Studies in the field of complex systems have generated new perspectives on management in social organizations such as hospitals. Much of this research appears as a natural extension of the cross-disciplinary field of systems theory. This is the 15th in a series of articles applying complex systems science to the traditional management concepts of planning, organizing, directing, coordinating, and controlling. In this article, the authors discuss healthcare social networks as a hierarchy of embedded complex adaptive systems. The authors further examine the use of social network analysis tools as a means to understand complex communication patterns and reduce medical errors. PMID:20798616

  16. Computerized Adaptive Diagnosis and Testing of Mental Health Disorders.

    PubMed

    Gibbons, Robert D; Weiss, David J; Frank, Ellen; Kupfer, David

    2016-03-28

    In this review we explore recent developments in computerized adaptive diagnostic screening and computerized adaptive testing for the presence and severity of mental health disorders such as depression, anxiety, and mania. The statistical methodology is unique in that it is based on multidimensional item response theory (severity) and random forests (diagnosis) instead of traditional mental health measurement based on classical test theory (a simple total score) or unidimensional item response theory. We show that the information contained in large item banks consisting of hundreds of symptom items can be efficiently calibrated using multidimensional item response theory, and the information contained in these large item banks can be precisely extracted using adaptive administration of a small set of items for each individual. In terms of diagnosis, computerized adaptive diagnostic screening can accurately track an hour-long face-to-face clinician diagnostic interview for major depressive disorder (as an example) in less than a minute using an average of four questions with unprecedented high sensitivity and specificity. Directions for future research and applications are discussed. PMID:26651865

  17. Evolutionary adaptation of phenotypic plasticity in a synthetic microbial system

    NASA Astrophysics Data System (ADS)

    Tans, Sander

    2010-03-01

    While phenotypic plasticity -the capability to respond to the environment- is vital to organisms, tests of its adaptation have remained indecisive because constraints and selection in variable environments are unknown and entangled. We show that one can determine the phenotype-fitness landscape that specifies selection on plasticity, by uncoupling the environmental cue and stress in a genetically engineered microbial system. Evolutionary trajectories revealed genetic constraints in a regulatory protein, which imposed cross-environment trade-offs that favored specialization. However, depending on the synchronicity and amplitude of the applied cue and stress variations, adaptation could break constraints, resolve trade-offs, and evolve optimal phenotypes that exhibit qualitatively altered (inverse) responses to the cue. Our results provide a first step to explain the adaptive origins of complex behavior in heterogeneous environments.

  18. Development and Simulation Testing of a Computerized Adaptive Version of the Philadelphia Naming Test

    ERIC Educational Resources Information Center

    Hula, William D.; Kellough, Stacey; Fergadiotis, Gerasimos

    2015-01-01

    Purpose: The purpose of this study was to develop a computerized adaptive test (CAT) version of the Philadelphia Naming Test (PNT; Roach, Schwartz, Martin, Grewal, & Brecher, 1996), to reduce test length while maximizing measurement precision. This article is a direct extension of a companion article (Fergadiotis, Kellough, & Hula, 2015),…

  19. A Computerized Implementation of a Flexilevel Test and Its Comparison with a Bayesian Computerized Adaptive Test.

    ERIC Educational Resources Information Center

    DeAyala, R. J.; Koch, William R.

    A computerized flexilevel test was implemented and its ability estimates were compared with those of a Bayesian estimation based computerized adaptive test (CAT) as well as with known true ability estimates. Results showed that when the flexilevel test was terminated according to Lord's criterion, its ability estimates were highly and…

  20. DKIST Adaptive Optics System: Simulation Results

    NASA Astrophysics Data System (ADS)

    Marino, Jose; Schmidt, Dirk

    2016-05-01

    The 4 m class Daniel K. Inouye Solar Telescope (DKIST), currently under construction, will be equipped with an ultra high order solar adaptive optics (AO) system. The requirements and capabilities of such a solar AO system are beyond those of any other solar AO system currently in operation. We must rely on solar AO simulations to estimate and quantify its performance.We present performance estimation results of the DKIST AO system obtained with a new solar AO simulation tool. This simulation tool is a flexible and fast end-to-end solar AO simulator which produces accurate solar AO simulations while taking advantage of current multi-core computer technology. It relies on full imaging simulations of the extended field Shack-Hartmann wavefront sensor (WFS), which directly includes important secondary effects such as field dependent distortions and varying contrast of the WFS sub-aperture images.

  1. Progress with the lick adaptive optics system

    SciTech Connect

    Gavel, D T; Olivier, S S; Bauman, B; Max, C E; Macintosh, B

    2000-03-01

    Progress and results of observations with the Lick Observatory Laser Guide Star Adaptive Optics System are presented. This system is optimized for diffraction-limited imaging in the near infrared, 1-2 micron wavelength bands. We describe our development efforts in a number of component areas including, a redesign of the optical bench layout, the commissioning of a new infrared science camera, and improvements to the software and user interface. There is also an ongoing effort to characterize the system performance with both natural and laser guide stars and to fold this data into a refined system model. Such a model can be used to help plan future observations, for example, predicting the point-spread function as a function of seeing and guide star magnitude.

  2. Robust Systems Test Framework

    SciTech Connect

    Ballance, Robert A.

    2003-01-01

    The Robust Systems Test Framework (RSTF) provides a means of specifying and running test programs on various computation platforms. RSTF provides a level of specification above standard scripting languages. During a set of runs, standard timing information is collected. The RSTF specification can also gather job-specific information, and can include ways to classify test outcomes. All results and scripts can be stored into and retrieved from an SQL database for later data analysis. RSTF also provides operations for managing the script and result files, and for compiling applications and gathering compilation information such as optimization flags.

  3. System for testing bearings

    NASA Astrophysics Data System (ADS)

    Gibson, John C.

    1993-07-01

    Disclosed here is a system for testing bearings wherein a pair of spaced bearings provides support for a shaft on which is mounted a bearing to be tested, this bearing being mounted in a bearing holder spaced from and in alignment with the pair of bearings. The bearing holder is provided with an annular collar positioned in an opening in the bearing holder for holding the bearing to be tested. A screw threaded through the bearing holder into engagement with the annular collar can be turned to force the collar radially out of alignment with the pair of bearings to apply a radial load to the bearing.

  4. Robust Systems Test Framework

    2003-01-01

    The Robust Systems Test Framework (RSTF) provides a means of specifying and running test programs on various computation platforms. RSTF provides a level of specification above standard scripting languages. During a set of runs, standard timing information is collected. The RSTF specification can also gather job-specific information, and can include ways to classify test outcomes. All results and scripts can be stored into and retrieved from an SQL database for later data analysis. RSTF alsomore » provides operations for managing the script and result files, and for compiling applications and gathering compilation information such as optimization flags.« less

  5. Adaptive stimulus optimization for sensory systems neuroscience

    PubMed Central

    DiMattina, Christopher; Zhang, Kechen

    2013-01-01

    In this paper, we review several lines of recent work aimed at developing practical methods for adaptive on-line stimulus generation for sensory neurophysiology. We consider various experimental paradigms where on-line stimulus optimization is utilized, including the classical optimal stimulus paradigm where the goal of experiments is to identify a stimulus which maximizes neural responses, the iso-response paradigm which finds sets of stimuli giving rise to constant responses, and the system identification paradigm where the experimental goal is to estimate and possibly compare sensory processing models. We discuss various theoretical and practical aspects of adaptive firing rate optimization, including optimization with stimulus space constraints, firing rate adaptation, and possible network constraints on the optimal stimulus. We consider the problem of system identification, and show how accurate estimation of non-linear models can be highly dependent on the stimulus set used to probe the network. We suggest that optimizing stimuli for accurate model estimation may make it possible to successfully identify non-linear models which are otherwise intractable, and summarize several recent studies of this type. Finally, we present a two-stage stimulus design procedure which combines the dual goals of model estimation and model comparison and may be especially useful for system identification experiments where the appropriate model is unknown beforehand. We propose that fast, on-line stimulus optimization enabled by increasing computer power can make it practical to move sensory neuroscience away from a descriptive paradigm and toward a new paradigm of real-time model estimation and comparison. PMID:23761737

  6. Bayesian Decision Theory for Multi-Category Adaptive Testing

    NASA Astrophysics Data System (ADS)

    Marinagi, Catherine C.; Kaburlasos, Vassilis G.

    2008-09-01

    This work presents a method for item selection in adaptive tests based on Bayesian Decision Theory (BDT). Multiple categories of examinee's competence level are assumed. The method determines the probability an examinee belongs to each category using Bayesian statistics. Before starting a test, prior probabilities of an examinee are assumed. Then, each time an examinee responds to a single item, a new competence level is estimated "a-posteriori" using item response and prior probabilities values. A customized focus-of-attention vector of probabilities is estimated, which is used to draw the next item from the Item Bank. The latter vector considers both Personalized Cost and content balancing percentages of items.

  7. Test stand system for vacuum chambers

    NASA Technical Reports Server (NTRS)

    Newman, D. F. (Inventor)

    1973-01-01

    A test stand system for supporting test items in a vacuum chamber is described. The system consists of a frame adapted to conform to the inside of the vacuum chamber and supporting a central vertical shaft. The shaft rotates on bearings located at each end of the shaft. Several vertically spaced plates which fixed to the vertical shaft may be adjusted for height to support the test equipment as required. The test equipment may be rotated during tests without disturbing the vacuum by a manually actuated drive external to the vacuum chamber.

  8. Adaptive-passive vibration control systems for industrial applications

    NASA Astrophysics Data System (ADS)

    Mayer, D.; Pfeiffer, T.; Vrbata, J.; Melz, T.

    2015-04-01

    Tuned vibration absorbers have become common for passive vibration reduction in many industrial applications. Lightly damped absorbers (also called neutralizers) can be used to suppress narrowband disturbances by tuning them to the excitation frequency. If the resonance is adapted in-operation, the performance of those devices can be significantly enhanced, or inertial mass can be decreased. However, the integration of actuators, sensors and control electronics into the system raises new design challenges. In this work, the development of adaptive-passive systems for vibration reduction at an industrial scale is presented. As an example, vibration reduction of a ship engine was studied in a full scale test. Simulations were used to study the feasibility and evaluate the system concept at an early stage. Several ways to adjust the resonance of the neutralizer were evaluated, including piezoelectric actuation and common mechatronic drives. Prototypes were implemented and tested. Since vibration absorbers suffer from high dynamic loads, reliability tests were used to assess the long-term behavior under operational conditions and to improve the components. It was proved that the adaptive systems are capable to withstand the mechanical loads in an industrial application. Also a control strategy had to be implemented in order to track the excitation frequency. The most mature concepts were integrated into the full scale test. An imbalance exciter was used to simulate the engine vibrations at a realistic level experimentally. The neutralizers were tested at varying excitation frequencies to evaluate the tracking capabilities of the control system. It was proved that a significant vibration reduction is possible.

  9. A Knowledge-Structure-Based Adaptive Dynamic Assessment System for Calculus Learning

    ERIC Educational Resources Information Center

    Ting, M.-Y.; Kuo, B.-C.

    2016-01-01

    The purpose of this study was to investigate the effect of a calculus system that was designed using an adaptive dynamic assessment (DA) framework on performance in the "finding an area using an integral". In this study, adaptive testing and dynamic assessment were combined to provide different test items depending on students'…

  10. NASA Facts: Nanosatellite Launch Adapter System (NLAS)

    NASA Technical Reports Server (NTRS)

    Chartres, James; Cappuccio, Gelsomina

    2013-01-01

    The Nanosatellite Launch Adapter System (NLAS) was developed to increase access to space while simplifying the integration process of miniature satellites, called nanosats or cubesats, onto launch vehicles. A standard cubesat measures about 4inches (10 cm) long, 4 inches wide,and 4 inches high, and is called a one-unit (1U) cubesat. A single NLAS provides the capability to deploy 24U of cubesats. The system is designed to accommodate satellites measuring 1U, 1.5U, 2U, 3U and 6U sizes for deployment into orbit. The NLAS may be configured for use on different launch vehicles. The system also enables flight demonstrations of new technologies in the space environment.

  11. Feasibility of the adaptive and automatic presentation of tasks (ADAPT) system for rehabilitation of upper extremity function post-stroke

    PubMed Central

    2011-01-01

    Background Current guidelines for rehabilitation of arm and hand function after stroke recommend that motor training focus on realistic tasks that require reaching and manipulation and engage the patient intensively, actively, and adaptively. Here, we investigated the feasibility of a novel robotic task-practice system, ADAPT, designed in accordance with such guidelines. At each trial, ADAPT selects a functional task according to a training schedule and with difficulty based on previous performance. Once the task is selected, the robot picks up and presents the corresponding tool, simulates the dynamics of the tasks, and the patient interacts with the tool to perform the task. Methods Five participants with chronic stroke with mild to moderate impairments (> 9 months post-stroke; Fugl-Meyer arm score 49.2 ± 5.6) practiced four functional tasks (selected out of six in a pre-test) with ADAPT for about one and half hour and 144 trials in a pseudo-random schedule of 3-trial blocks per task. Results No adverse events occurred and ADAPT successfully presented the six functional tasks without human intervention for a total of 900 trials. Qualitative analysis of trajectories showed that ADAPT simulated the desired task dynamics adequately, and participants reported good, although not excellent, task fidelity. During training, the adaptive difficulty algorithm progressively increased task difficulty leading towards an optimal challenge point based on performance; difficulty was then continuously adjusted to keep performance around the challenge point. Furthermore, the time to complete all trained tasks decreased significantly from pretest to one-hour post-test. Finally, post-training questionnaires demonstrated positive patient acceptance of ADAPT. Conclusions ADAPT successfully provided adaptive progressive training for multiple functional tasks based on participant's performance. Our encouraging results establish the feasibility of ADAPT; its efficacy will next be tested

  12. Adaptable formations utilizing heterogeneous unmanned systems

    NASA Astrophysics Data System (ADS)

    Barnes, Laura E.; Garcia, Richard; Fields, MaryAnne; Valavanis, Kimon

    2009-05-01

    This paper addresses the problem of controlling and coordinating heterogeneous unmanned systems required to move as a group while maintaining formation. We propose a strategy to coordinate groups of unmanned ground vehicles (UGVs) with one or more unmanned aerial vehicles (UAVs). UAVs can be utilized in one of two ways: (1) as alpha robots to guide the UGVs; and (2) as beta robots to surround the UGVs and adapt accordingly. In the first approach, the UAV guides a swarm of UGVs controlling their overall formation. In the second approach, the UGVs guide the UAVs controlling their formation. The unmanned systems are brought into a formation utilizing artificial potential fields generated from normal and sigmoid functions. These functions control the overall swarm geometry. Nonlinear limiting functions are defined to provide tighter swarm control by modifying and adjusting a set of control variables forcing the swarm to behave according to set constraints. Formations derived are subsets of elliptical curves but can be generalized to any curvilinear shape. Both approaches are demonstrated in simulation and experimentally. To demonstrate the second approach in simulation, a swarm of forty UAVs is utilized in a convoy protection mission. As a convoy of UGVs travels, UAVs dynamically and intelligently adapt their formation in order to protect the convoy of vehicles as it moves. Experimental results are presented to demonstrate the approach using a fully autonomous group of three UGVs and a single UAV helicopter for coordination.

  13. Adaptive cyber-attack modeling system

    NASA Astrophysics Data System (ADS)

    Gonsalves, Paul G.; Dougherty, Edward T.

    2006-05-01

    The pervasiveness of software and networked information systems is evident across a broad spectrum of business and government sectors. Such reliance provides an ample opportunity not only for the nefarious exploits of lone wolf computer hackers, but for more systematic software attacks from organized entities. Much effort and focus has been placed on preventing and ameliorating network and OS attacks, a concomitant emphasis is required to address protection of mission critical software. Typical software protection technique and methodology evaluation and verification and validation (V&V) involves the use of a team of subject matter experts (SMEs) to mimic potential attackers or hackers. This manpower intensive, time-consuming, and potentially cost-prohibitive approach is not amenable to performing the necessary multiple non-subjective analyses required to support quantifying software protection levels. To facilitate the evaluation and V&V of software protection solutions, we have designed and developed a prototype adaptive cyber attack modeling system. Our approach integrates an off-line mechanism for rapid construction of Bayesian belief network (BN) attack models with an on-line model instantiation, adaptation and knowledge acquisition scheme. Off-line model construction is supported via a knowledge elicitation approach for identifying key domain requirements and a process for translating these requirements into a library of BN-based cyber-attack models. On-line attack modeling and knowledge acquisition is supported via BN evidence propagation and model parameter learning.

  14. Adapting the Bilingual Aphasia Test to Rarotongan (Cook Islands Maori): Linguistic and Clinical Considerations

    ERIC Educational Resources Information Center

    Amberber, Amanda Miller

    2011-01-01

    This article describes the adaptation of the Bilingual Aphasia Test (BAT) to the Rarotongan dialect of Cook Islands Maori, a Polynesian language spoken in the Cook Islands and expatriate communities. A brief linguistic sketch of Rarotongan is presented. As Rarotongan is characterised by a complex pronominal system, "a" versus "o" possession and…

  15. Firestar-"D": Computerized Adaptive Testing Simulation Program for Dichotomous Item Response Theory Models

    ERIC Educational Resources Information Center

    Choi, Seung W.; Podrabsky, Tracy; McKinney, Natalie

    2012-01-01

    Computerized adaptive testing (CAT) enables efficient and flexible measurement of latent constructs. The majority of educational and cognitive measurement constructs are based on dichotomous item response theory (IRT) models. An integral part of developing various components of a CAT system is conducting simulations using both known and empirical…

  16. On the Impact of Adaptive Test Question Selection for Learning Efficiency

    ERIC Educational Resources Information Center

    Barla, Michal; Bielikova, Maria; Ezzeddinne, Anna Bou; Kramar, Tomas; Simko, Marian; Vozar, Oto

    2010-01-01

    In this paper we present a method for adaptive selection of test questions according to the individual needs of students within a web-based educational system. It functions as a combination of three particular methods. The first method is based on the course structure and focuses on the selection of the most appropriate topic for learning. The…

  17. A Feedback Control Strategy for Enhancing Item Selection Efficiency in Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Weissman, Alexander

    2006-01-01

    A computerized adaptive test (CAT) may be modeled as a closed-loop system, where item selection is influenced by trait level ([theta]) estimation and vice versa. When discrepancies exist between an examinee's estimated and true [theta] levels, nonoptimal item selection is a likely result. Nevertheless, examinee response behavior consistent with…

  18. Adaptation to Room Acoustics Using the Modified Rhyme Test

    PubMed Central

    Brandewie, Eugene; Zahorik, Pavel

    2012-01-01

    The negative effect of reverberant sound energy on speech intelligibility is well documented. Recently, however, prior exposure to room acoustics has been shown to increase intelligibility for a number of listeners in simulated room environments. This room adaptation effect, a possible extension of dynamic echo suppression, has been shown to be specific to reverberant rooms and requires binaural input. Because this effect has been demonstrated only using the Coordinated Response Measure (CRM) corpus it is important to determine whether the increase in intelligibility scores reported previously was due to the specific nature of the CRM task. Here we demonstrate a comparable room-acoustic effect using the Modified Rhyme Test (MRT) corpus in multiple room environments. The results are consistent with the idea that the room adaptation effect may be a natural phenomenon of listening in reverberant environments. PMID:23437415

  19. Power systems testing

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The Space Station Freedom (SSF) will give the U.S. a permanent manned presence in space in 1999. The SSF underwent its final design concept in 1991. Launches of hardware will begin in late 1995, and the SSF will become operational in the man tended configuration in 1997. Additional Space Shuttle flights between 1997 and 1999 will complete the SSF. Along with international partners, a crew of four astronauts will conduct long-term experimentation in the microgravity environment of the orbiting spacecraft. Lewis Research Center, along with its prime contractor, will provide the electrical power system (EPS) for SSF. Two major testing facilities at the Lewis Research Center will support the Lewis EPS. The Power Systems Facility provides test beds for life testing the station batteries and the power management distribution system testbed. This testbed simulates two channels of the EPS. The Space Power Facility at the Lewis Plum Brook Station is the largest vacuum chamber in the world. Within this chamber, a simulated space environment, testing of full-size EPS components will occur.

  20. Flexible Material Systems Testing

    NASA Technical Reports Server (NTRS)

    Lin, John K.; Shook, Lauren S.; Ware, Joanne S.; Welch, Joseph V.

    2010-01-01

    An experimental program has been undertaken to better characterize the stress-strain characteristics of flexible material systems to support a NASA ground test program for inflatable decelerator material technology. A goal of the current study is to investigate experimental methods for the characterization of coated woven material stiffness. This type of experimental mechanics data would eventually be used to define the material inputs of fluid-structure interaction simulation models. The test methodologies chosen for this stress-strain characterization are presented along with the experimental results.

  1. Contrarian behavior in a complex adaptive system

    NASA Astrophysics Data System (ADS)

    Liang, Y.; An, K. N.; Yang, G.; Huang, J. P.

    2013-01-01

    Contrarian behavior is a kind of self-organization in complex adaptive systems (CASs). Here we report the existence of a transition point in a model resource-allocation CAS with contrarian behavior by using human experiments, computer simulations, and theoretical analysis. The resource ratio and system predictability serve as the tuning parameter and order parameter, respectively. The transition point helps to reveal the positive or negative role of contrarian behavior. This finding is in contrast to the common belief that contrarian behavior always has a positive role in resource allocation, say, stabilizing resource allocation by shrinking the redundancy or the lack of resources. It is further shown that resource allocation can be optimized at the transition point by adding an appropriate size of contrarians. This work is also expected to be of value to some other fields ranging from management and social science to ecology and evolution.

  2. Vendor System Vulnerability Testing Test Plan

    SciTech Connect

    James R. Davidson

    2005-01-01

    The Idaho National Laboratory (INL) prepared this generic test plan to provide clients (vendors, end users, program sponsors, etc.) with a sense of the scope and depth of vulnerability testing performed at the INL’s Supervisory Control and Data Acquisition (SCADA) Test Bed and to serve as an example of such a plan. Although this test plan specifically addresses vulnerability testing of systems applied to the energy sector (electric/power transmission and distribution and oil and gas systems), it is generic enough to be applied to control systems used in other critical infrastructures such as the transportation sector, water/waste water sector, or hazardous chemical production facilities. The SCADA Test Bed is established at the INL as a testing environment to evaluate the security vulnerabilities of SCADA systems, energy management systems (EMS), and distributed control systems. It now supports multiple programs sponsored by the U.S. Department of Energy, the U.S. Department of Homeland Security, other government agencies, and private sector clients. This particular test plan applies to testing conducted on a SCADA/EMS provided by a vendor. Before performing detailed vulnerability testing of a SCADA/EMS, an as delivered baseline examination of the system is conducted, to establish a starting point for all-subsequent testing. The series of baseline tests document factory delivered defaults, system configuration, and potential configuration changes to aid in the development of a security plan for in depth vulnerability testing. The baseline test document is provided to the System Provider,a who evaluates the baseline report and provides recommendations to the system configuration to enhance the security profile of the baseline system. Vulnerability testing is then conducted at the SCADA Test Bed, which provides an in-depth security analysis of the Vendor’s system.b a. The term System Provider replaces the name of the company/organization providing the system

  3. Practical Considerations about Expected A Posteriori Estimation in Adaptive Testing: Adaptive A Priori, Adaptive Correction for Bias, and Adaptive Integration Interval.

    ERIC Educational Resources Information Center

    Raiche, Gilles; Blais, Jean-Guy

    In a computerized adaptive test (CAT), it would be desirable to obtain an acceptable precision of the proficiency level estimate using an optimal number of items. Decreasing the number of items is accompanied, however, by a certain degree of bias when the true proficiency level differs significantly from the a priori estimate. G. Raiche (2000) has…

  4. Systemic Cold Stress Adaptation of Chlamydomonas reinhardtii*

    PubMed Central

    Valledor, Luis; Furuhashi, Takeshi; Hanak, Anne-Mette; Weckwerth, Wolfram

    2013-01-01

    Chlamydomonas reinhardtii is one of the most important model organisms nowadays phylogenetically situated between higher plants and animals (Merchant et al. 2007). Stress adaptation of this unicellular model algae is in the focus because of its relevance to biomass and biofuel production. Here, we have studied cold stress adaptation of C. reinhardtii hitherto not described for this algae whereas intensively studied in higher plants. Toward this goal, high throughput mass spectrometry was employed to integrate proteome, metabolome, physiological and cell-morphological changes during a time-course from 0 to 120 h. These data were complemented with RT-qPCR for target genes involved in central metabolism, signaling, and lipid biosynthesis. Using this approach dynamics in central metabolism were linked to cold-stress dependent sugar and autophagy pathways as well as novel genes in C. reinhardtii such as CKIN1, CKIN2 and a hitherto functionally not annotated protein named CKIN3. Cold stress affected extensively the physiology and the organization of the cell. Gluconeogenesis and starch biosynthesis pathways are activated leading to a pronounced starch and sugar accumulation. Quantitative lipid profiles indicate a sharp decrease in the lipophilic fraction and an increase in polyunsaturated fatty acids suggesting this as a mechanism of maintaining membrane fluidity. The proteome is completely remodeled during cold stress: specific candidates of the ribosome and the spliceosome indicate altered biosynthesis and degradation of proteins important for adaptation to low temperatures. Specific proteasome degradation may be mediated by the observed cold-specific changes in the ubiquitinylation system. Sparse partial least squares regression analysis was applied for protein correlation network analysis using proteins as predictors and Fv/Fm, FW, total lipids, and starch as responses. We applied also Granger causality analysis and revealed correlations between proteins and

  5. The Magellan Telescope Deformable Secondary Adaptive Optics System

    NASA Astrophysics Data System (ADS)

    Close, Laird M.; Gasho, V.; Kopon, D.; Males, J.; Hinz, P.; Hare, T.

    2009-05-01

    We present the adaptive optics system for the 6.5m Magellan Telescope. The Magellan telescope is a 6.5m Gregorian telescope located in southern Chile at Las Campanas Observatory. The Gregorian design allows for an adaptive secondary mirror that can be tested off-sky in a straight-forward manner. We have fabricated a 85 cm diameter aspheric adaptive secondary with our subcontractors and partners. This secondary has 585 actuators with 1 msec response times. The secondary will allow low emissivity AO science. We will achieve very high Strehls ( 98%) in the Mid-IR (8-26 microns) imaged with the BLINC/MIRAC4 Mid-IR camera. This will allow the first "super-resolution" Mid-IR studies of dusty southern objects. We will employ a high order (585 mode) pyramid wavefront sensor similar to that used in the Large Binocular Telescope AO systems. The relatively high actuator count for a 6.5m telescope will allow modest Strehls to be obtained in the visible. Our visible light AO CCD camera is fed by a beamsplitter piggy backed on the wavefront sensor system. We have addressed several difficult issues with 20 milliarcsec diffraction-limited imaging in the visible with our VisAO system. The Magellan AO system successfully passed PDR in December 2008 and should have first light in early 2011.

  6. The Selection of Test Items for Decision Making with a Computer Adaptive Test.

    ERIC Educational Resources Information Center

    Spray, Judith A.; Reckase, Mark D.

    The issue of test-item selection in support of decision making in adaptive testing is considered. The number of items needed to make a decision is compared for two approaches: selecting items from an item pool that are most informative at the decision point or selecting items that are most informative at the examinee's ability level. The first…

  7. Constraining Item Exposure in Computerized Adaptive Testing with Shadow Tests. Research Report.

    ERIC Educational Resources Information Center

    van der Linden, Wim J.; Veldkamp, Bernard P.

    Item-exposure control in computerized adaptive testing is implemented by imposing item-ineligibility constraints on the assembly process of the shadow tests. The method resembles J. Sympson and R. Hetter's (1985) method of item-exposure control in that the decisions to impose the constraints are probabilistic. However, the method does not require…

  8. Modeling Student Test-Taking Motivation in the Context of an Adaptive Achievement Test

    ERIC Educational Resources Information Center

    Wise, Steven L.; Kingsbury, G. Gage

    2016-01-01

    This study examined the utility of response time-based analyses in understanding the behavior of unmotivated test takers. For the data from an adaptive achievement test, patterns of observed rapid-guessing behavior and item response accuracy were compared to the behavior expected under several types of models that have been proposed to represent…

  9. Assembling a Computerized Adaptive Testing Item Pool as a Set of Linear Tests

    ERIC Educational Resources Information Center

    van der Linden, Wim J.; Ariel, Adelaide; Veldkamp, Bernard P.

    2006-01-01

    Test-item writing efforts typically results in item pools with an undesirable correlational structure between the content attributes of the items and their statistical information. If such pools are used in computerized adaptive testing (CAT), the algorithm may be forced to select items with less than optimal information, that violate the content…

  10. Adaptive Testing with Equated Number-Correct Scoring. Research Report 99-02.

    ERIC Educational Resources Information Center

    van der Linden, Wim J.

    A constrained computerized adaptive testing (CAT) algorithm is presented that automatically equates the number-correct scores on adaptive tests. The algorithm can be used to equate number-correct scores across different administrations of the same adaptive test as well as to an external reference test. The constraints are derived from a set of…

  11. Low Temperature Shape Memory Alloys for Adaptive, Autonomous Systems Project

    NASA Technical Reports Server (NTRS)

    Falker, John; Zeitlin, Nancy; Williams, Martha; Benafan, Othmane; Fesmire, James

    2015-01-01

    The objective of this joint activity between Kennedy Space Center (KSC) and Glenn Research Center (GRC) is to develop and evaluate the applicability of 2-way SMAs in proof-of-concept, low-temperature adaptive autonomous systems. As part of this low technology readiness (TRL) activity, we will develop and train low-temperature novel, 2-way shape memory alloys (SMAs) with actuation temperatures ranging from 0 C to 150 C. These experimental alloys will also be preliminary tested to evaluate their performance parameters and transformation (actuation) temperatures in low- temperature or cryogenic adaptive proof-of-concept systems. The challenge will be in the development, design, and training of the alloys for 2-way actuation at those temperatures.

  12. Igniter adapter-to-igniter chamber deflection test

    NASA Technical Reports Server (NTRS)

    Cook, M.

    1990-01-01

    Testing was performed to determine the maximum RSRM igniter adapter-to-igniter chamber joint deflection at the crown of the inner joint primary seal. The deflection data was gathered to support igniter inner joint gasket resiliency predictions which led to launch commit criteria temperature determinations. The proximity (deflection) gage holes for the first test (Test No. 1) were incorrectly located; therefore, the test was declared a non-test. Prior to Test No. 2, test article configuration was modified with the correct proximity gage locations. Deflection data were successfully acquired during Test No. 2. However, the proximity gage deflection measurements were adversely affected by temperature increases. Deflections measured after the temperature rise at the proximity gages were considered unreliable. An analysis was performed to predict the maximum deflections based on the reliable data measured before the detectable temperature rise. Deflections to the primary seal crown location were adjusted to correspond to the time of maximum expected operating pressure (2,159 psi) to account for proximity gage bias, and to account for maximum attach and special bolt relaxation. The maximum joint deflection for the igniter inner joint at the crown of the primary seal, accounting for all significant correction factors, was 0.0031 in. (3.1 mil). Since the predicted (0.003 in.) and tested maximum deflection values were sufficiently close, the launch commit criteria was not changed as a result of this test. Data from this test should be used to determine if the igniter inner joint gasket seals are capable of maintaining sealing capability at a joint displacement of (1.4) x (0.0031 in.) = 0.00434 inches. Additional testing should be performed to increase the database on igniter deflections and address launch commit criteria temperatures.

  13. Insulation bonding test system

    NASA Technical Reports Server (NTRS)

    Beggs, J. M.; Johnston, G. D.; Coleman, A. D.; Portwood, J. N.; Saunders, J. M.; Redmon, J. W.; Porter, A. C. (Inventor)

    1984-01-01

    A method and a system for testing the bonding of foam insulation attached to metal is described. The system involves the use of an impacter which has a calibrated load cell mounted on a plunger and a hammer head mounted on the end of the plunger. When the impacter strikes the insulation at a point to be tested, the load cell measures the force of the impact and the precise time interval during which the hammer head is in contact with the insulation. This information is transmitted as an electrical signal to a load cell amplifier where the signal is conditioned and then transmitted to a fast Fourier transform (FFT) analyzer. The FFT analyzer produces energy spectral density curves which are displayed on a video screen. The termination frequency of the energy spectral density curve may be compared with a predetermined empirical scale to determine whether a igh quality bond, good bond, or debond is present at the point of impact.

  14. SAFER Rescue System Tested

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Astronauts Carl J. Meade and Mark C. Lee (red strip on suit) test the new Simplified Aid for EVA Rescue (SAFER) system some 130 nautical miles above Earth. The pair was actually performing an in-space rehearsal or demonstration of a contingency rescue using never-before flown hardware. Meade, who here wears the small back-pack unit with its complementary chest-mounted control unit, and Lee anchored to the Space Shuttle Discovery's Remote Manipulator System (RMS) robot arm, took turns using the SAFER hardware during their shared space walk.

  15. Vehicle brake testing system

    DOEpatents

    Stevens, Samuel S [Harriman, TN; Hodgson, Jeffrey W [Lenoir City, TN

    2002-11-19

    This invention relates to a force measuring system capable of measuring forces associated with vehicle braking and of evaluating braking performance. The disclosure concerns an invention which comprises a first row of linearly aligned plates, a force bearing surface extending beneath and beside the plates, vertically oriented links and horizontally oriented links connecting each plate to a force bearing surface, a force measuring device in each link, a transducer coupled to each force measuring device, and a computing device coupled to receive an output signal from the transducer indicative of measured force in each force measuring device. The present invention may be used for testing vehicle brake systems.

  16. The Limits to Adaptation: A Systems Approach

    EPA Science Inventory

    The ability to adapt to climate change is delineated by capacity thresholds, after which climate damages begin to overwhelm the adaptation response. Such thresholds depend upon physical properties (natural processes and engineering parameters), resource constraints (expressed th...

  17. Intercellular Communication in the Adaptive Immune System

    NASA Astrophysics Data System (ADS)

    Chakraborty, Arup

    2004-03-01

    Higher organisms, like humans, have an adaptive immune system that can respond to pathogens that have not been encountered before. T lymphocytes (T cells) are the orchestrators of the adaptive immune response. They interact with cells, called antigen presenting cells (APC), that display molecular signatures of pathogens. Recently, video microscopy experiments have revealed that when T cells detect antigen on APC surfaces, a spatially patterned supramolecular assembly of different types of molecules forms in the junction between cell membranes. This recognition motif is implicated in information transfer between APC and T cells, and so, is labeled the immunological synapse. The observation of synapse formation sparked two broad questions: How does the synapse form? Why does the synapse form? I will describe progress made in answering these fundamental questions in biology by synergistic use of statistical mechanical theory/computation, chemical engineering principles, and genetic and biochemical experiments. The talk will also touch upon mechanisms that may underlie the extreme sensitivity with which T cells discriminate between self and non-self.

  18. Adaptive Mesh Refinement in Curvilinear Body-Fitted Grid Systems

    NASA Technical Reports Server (NTRS)

    Steinthorsson, Erlendur; Modiano, David; Colella, Phillip

    1995-01-01

    To be truly compatible with structured grids, an AMR algorithm should employ a block structure for the refined grids to allow flow solvers to take advantage of the strengths of unstructured grid systems, such as efficient solution algorithms for implicit discretizations and multigrid schemes. One such algorithm, the AMR algorithm of Berger and Colella, has been applied to and adapted for use with body-fitted structured grid systems. Results are presented for a transonic flow over a NACA0012 airfoil (AGARD-03 test case) and a reflection of a shock over a double wedge.

  19. Development of a Computerized Adaptive Test for Schizotypy Assessment

    PubMed Central

    Fonseca-Pedrero, Eduardo; Menéndez, Luis Fernando; Paino, Mercedes; Lemos-Giráldez, Serafín; Muñiz, José

    2013-01-01

    Background Schizotypal traits in adolescents from the general population represent the behavioral expression of liability for psychotic disorders. Schizotypy assessment in this sector of population has advanced considerably in the last few years; however, it is necessary to incorporate recent advances in psychological and educational measurement. Objective The main goal of this study was to develop a Computerized Adaptive Test (CAT) to evaluate schizotypy through “The Oviedo Questionnaire for Schizotypy Assessment” (ESQUIZO-Q), in non-clinical adolescents. Methods The final sample consisted of 3,056 participants, 1,469 males, with a mean age of 15.9 years (SD = 1.2). Results The results indicated that the ESQUIZO-Q scores presented adequate psychometric properties under both Classical Test Theory and Item Response Theory. The Information Function estimated using the Gradual Response Model indicated that the item pool effectively assesses schizotypy at the high end of the latent trait. The correlation between the CAT total scores and the paper-and-pencil test was 0.92. The mean number of presented items in the CAT with the standard error fixed at ≤0.30 was of 34 items. Conclusion The CAT showed adequate psychometric properties for schizotypy assessment in the general adolescent population. The ESQUIZO-Q adaptive version could be used as a screening method for the detection of adolescents at risk for psychosis in both educational and mental health settings. PMID:24019907

  20. The curvature adaptive optics system modeling

    NASA Astrophysics Data System (ADS)

    Yang, Qiang

    A curvature adaptive optics (AO) simulation system has been built. The simulation is based on the Hokupa'a-36 AO system for the NASA IRTF 3m telescope and the Hokupa'a-85 AO system for the Gemini Near Infrared Coronagraphic Imager. Several sub-models are built separately for the AO simulation system, and they are: (1) generation and propagation of atmospheric phase screens, (2) the bimorph deformable mirror (DM), (3) the curvature wave-front sensor (CWFS), (4) generation of response functions, interaction matrices and calculation of command matrices, (5) Fresnel propagation from the DM pupil to the lenslet pupil, (6) AO servo loop, and (7) post processing. The AO simulation system is then applied to the effects of DM hysteresis, and to the optimization of DM actuator patterns for the Hokupa'a-85 and Hokupa'a-36 AO systems. In the first application, an enhancing Coleman-Hodgdon model is introduced to approximate the hysteresis curves, and then the Lambert W function is introduced to calculate the inverse of the Coleman-Hodgdon equation. Step response, transfer functions and Strehl Ratios from the AO system have been compared under the cases with/without DM hysteresis. The servo-loop results show that the bandwidth of an AO system is improved greatly after the DM hysteresis is corrected. In the second application, many issues of the bimorph mirror will be considered to optimize the DM patterns, and they include the type and length of the edge benders, gap size of electrodes, DM size, and DM curvature limit.

  1. Adaptive model training system and method

    DOEpatents

    Bickford, Randall L; Palnitkar, Rahul M; Lee, Vo

    2014-04-15

    An adaptive model training system and method for filtering asset operating data values acquired from a monitored asset for selectively choosing asset operating data values that meet at least one predefined criterion of good data quality while rejecting asset operating data values that fail to meet at least the one predefined criterion of good data quality; and recalibrating a previously trained or calibrated model having a learned scope of normal operation of the asset by utilizing the asset operating data values that meet at least the one predefined criterion of good data quality for adjusting the learned scope of normal operation of the asset for defining a recalibrated model having the adjusted learned scope of normal operation of the asset.

  2. Adaptive model training system and method

    DOEpatents

    Bickford, Randall L; Palnitkar, Rahul M

    2014-11-18

    An adaptive model training system and method for filtering asset operating data values acquired from a monitored asset for selectively choosing asset operating data values that meet at least one predefined criterion of good data quality while rejecting asset operating data values that fail to meet at least the one predefined criterion of good data quality; and recalibrating a previously trained or calibrated model having a learned scope of normal operation of the asset by utilizing the asset operating data values that meet at least the one predefined criterion of good data quality for adjusting the learned scope of normal operation of the asset for defining a recalibrated model having the adjusted learned scope of normal operation of the asset.

  3. Intelligent Optical Systems Using Adaptive Optics

    NASA Technical Reports Server (NTRS)

    Clark, Natalie

    2012-01-01

    Until recently, the phrase adaptive optics generally conjured images of large deformable mirrors being integrated into telescopes to compensate for atmospheric turbulence. However, the development of smaller, cheaper devices has sparked interest for other aerospace and commercial applications. Variable focal length lenses, liquid crystal spatial light modulators, tunable filters, phase compensators, polarization compensation, and deformable mirrors are becoming increasingly useful for other imaging applications including guidance navigation and control (GNC), coronagraphs, foveated imaging, situational awareness, autonomous rendezvous and docking, non-mechanical zoom, phase diversity, and enhanced multi-spectral imaging. The active components presented here allow flexibility in the optical design, increasing performance. In addition, the intelligent optical systems presented offer advantages in size and weight and radiation tolerance.

  4. Reading Test-Sentence Comprehension: An Adapted Version of Lobrot's Lecture 3 Test for Brazilian Portuguese.

    PubMed

    de Araújo Vilhena, Douglas; Sucena, Ana; Castro, São Luís; Pinheiro, Ângela Maria Vieira

    2016-02-01

    Our aim was to analyse the linguistic structure of the Lobrot's Lecture 3 (L3) reading test and to describe the procedure for its adaptation to a Brazilian cultural-linguistic context. The resulting adapted version is called the Reading Test-Sentence Comprehension [Teste de Leitura: Compreensão de Sentenças (TELCS)] and was developed using the European Portuguese adaptation of L3 as a reference. The present study was conducted in seven steps: (1) classification of the response alternatives of L3 test; (2) adaptation of the original sentences into Brazilian Portuguese; (3) back-translation; (4) adaptation of the distractors from TELCS; (5) configuration of TELCS; (6) pilot study; and (7) validation and standardization. In comparison with L3, TELCS included new linguistic and structural variables, such as frequency of occurrence of the distractors, gender neutrality and position of the target words. The instrument can be used for a collective screening or individual clinical administration purposes to evaluate the reading ability of second-to-fifth-grade and 7-to-11-year-old students. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26767907

  5. Application of network control systems for adaptive optics

    NASA Astrophysics Data System (ADS)

    Eager, Robert J.

    2008-04-01

    The communication architecture for most pointing, tracking, and high order adaptive optics control systems has been based on a centralized point-to-point and bus based approach. With the increased use of larger arrays and multiple sensors, actuators and processing nodes, these evolving systems require decentralized control, modularity, flexibility redundancy, integrated diagnostics, dynamic resource allocation, and ease of maintenance to support a wide range of experiments. Network control systems provide all of these critical functionalities. This paper begins with a quick overview of adaptive optics as a control system and communication architecture. It then provides an introduction to network control systems, identifying the key design areas that impact system performance. The paper then discusses the performance test results of a fielded network control system used to implement an adaptive optics system comprised of: a 10KHz, 32x32 spatial selfreferencing interferometer wave front sensor, a 705 channel "Tweeter" deformable mirror, a 177 channel "Woofer" deformable mirror, ten processing nodes, and six data acquisition nodes. The reconstructor algorithm utilized a modulo-2pi wave front phase measurement and a least-squares phase un-wrapper with branch point correction. The servo control algorithm is a hybrid of exponential and infinite impulse response controllers, with tweeter-to-woofer saturation offloading. This system achieved a first-pixel-out to last-mirror-voltage latency of 86 microseconds, with the network accounting for 4 microseconds of the measured latency. Finally, the extensibility of this architecture will be illustrated, by detailing the integration of a tracking sub-system into the existing network.

  6. Multistage Adaptive Testing for a Large-Scale Classification Test: Design, Heuristic Assembly, and Comparison with Other Testing Modes. ACT Research Report Series, 2012 (6)

    ERIC Educational Resources Information Center

    Zheng, Yi; Nozawa, Yuki; Gao, Xiaohong; Chang, Hua-Hua

    2012-01-01

    Multistage adaptive tests (MSTs) have gained increasing popularity in recent years. MST is a balanced compromise between linear test forms (i.e., paper-and-pencil testing and computer-based testing) and traditional item-level computer-adaptive testing (CAT). It combines the advantages of both. On one hand, MST is adaptive (and therefore more…

  7. Simulating Astronomical Adaptive Optics Systems Using Yao

    NASA Astrophysics Data System (ADS)

    Rigaut, François; Van Dam, Marcos

    2013-12-01

    Adaptive Optics systems are at the heart of the coming Extremely Large Telescopes generation. Given the importance, complexity and required advances of these systems, being able to simulate them faithfully is key to their success, and thus to the success of the ELTs. The type of systems envisioned to be built for the ELTs cover most of the AO breeds, from NGS AO to multiple guide star Ground Layer, Laser Tomography and Multi-Conjugate AO systems, with typically a few thousand actuators. This represents a large step up from the current generation of AO systems, and accordingly a challenge for existing AO simulation packages. This is especially true as, in the past years, computer power has not been following Moore's law in its most common understanding; CPU clocks are hovering at about 3GHz. Although the use of super computers is a possible solution to run these simulations, being able to use smaller machines has obvious advantages: cost, access, environmental issues. By using optimised code in an already proven AO simulation platform, we were able to run complex ELT AO simulations on very modest machines, including laptops. The platform is YAO. In this paper, we describe YAO, its architecture, its capabilities, the ELT-specific challenges and optimisations, and finally its performance. As an example, execution speed ranges from 5 iterations per second for a 6 LGS 60x60 subapertures Shack-Hartmann Wavefront sensor Laser Tomography AO system (including full physical image formation and detector characteristics) up to over 30 iterations/s for a single NGS AO system.

  8. Preliminary images from an adaptive imaging system.

    PubMed

    Griffiths, J A; Metaxas, M G; Pani, S; Schulerud, H; Esbrand, C; Royle, G J; Price, B; Rokvic, T; Longo, R; Asimidis, A; Bletsas, E; Cavouras, D; Fant, A; Gasiorek, P; Georgiou, H; Hall, G; Jones, J; Leaver, J; Li, G; Machin, D; Manthos, N; Matheson, J; Noy, M; Ostby, J M; Psomadellis, F; van der Stelt, P F; Theodoridis, S; Triantis, F; Turchetta, R; Venanzi, C; Speller, R D

    2008-06-01

    I-ImaS (Intelligent Imaging Sensors) is a European project aiming to produce real-time adaptive X-ray imaging systems using Monolithic Active Pixel Sensors (MAPS) to create images with maximum diagnostic information within given dose constraints. Initial systems concentrate on mammography and cephalography. In our system, the exposure in each image region is optimised and the beam intensity is a function of tissue thickness and attenuation, and also of local physical and statistical parameters in the image. Using a linear array of detectors, the system will perform on-line analysis of the image during the scan, followed by optimisation of the X-ray intensity to obtain the maximum diagnostic information from the region of interest while minimising exposure of diagnostically less important regions. This paper presents preliminary images obtained with a small area CMOS detector developed for this application. Wedge systems were used to modulate the beam intensity during breast and dental imaging using suitable X-ray spectra. The sensitive imaging area of the sensor is 512 x 32 pixels 32 x 32 microm(2) in size. The sensors' X-ray sensitivity was increased by coupling to a structured CsI(Tl) scintillator. In order to develop the I-ImaS prototype, the on-line data analysis and data acquisition control are based on custom-developed electronics using multiple FPGAs. Images of both breast tissues and jaw samples were acquired and different exposure optimisation algorithms applied. Results are very promising since the average dose has been reduced to around 60% of the dose delivered by conventional imaging systems without decrease in the visibility of details. PMID:18291697

  9. Nondestructive characterization of ductile cast iron by magnetic adaptive testing

    NASA Astrophysics Data System (ADS)

    Vertesy, G.; Uchimoto, T.; Tomáš, I.; Takagi, T.

    2010-10-01

    This paper reports correlation of magnetic descriptors with Brinell hardness and conductivity of ductile cast iron, aiming to develop a novel nondestructive method by magnetic adaptive testing. Four series of cast iron staircase-shaped samples were investigated by this method, where different cooling rates of samples during casting resulted in different structures of each sample. The flat samples were magnetized by an attached yoke, and sensitive descriptors were obtained from a proper evaluation, based on the measurements of series of magnetic minor hysteresis loops, without magnetic saturation of the samples. Results of the nondestructive magnetic tests were compared with destructive mechanical measurements of Brinell hardness and conductivity and good correlation was found between them.

  10. ADAPTIVE FULL-SPECTRUM SOLOR ENERGY SYSTEMS

    SciTech Connect

    Byard D. Wood

    2004-04-01

    This RD&D project is a three year team effort to develop a hybrid solar lighting (HSL) system that transports solar light from a paraboloidal dish concentrator to a luminaire via a large core polymer fiber optic. The luminaire can be a device to distribute sunlight into a space for the production of algae or it can be a device that is a combination of solar lighting and electric lighting. A benchmark prototype system has been developed to evaluate the HSL system. Sunlight is collected using a one-meter paraboloidal concentrator dish with two-axis tracking. A secondary mirror consisting of eight planar-segmented mirrors directs the visible part of the spectrum to eight fibers (receiver) and subsequently to eight luminaires. This results in about 8,200 lumens incident at each fiber tip. Each fiber can illuminate about 16.7 m{sup 2} (180 ft{sup 2}) of office space. The IR spectrum is directed to a thermophotovoltaic (TPV) array to produce electricity. During this reporting period, the project team made advancements in the design of the second generation (Alpha) system. For the Alpha system, the eight individual 12 mm fibers have been replaced with a centralized bundle of 3 mm fibers. The TRNSYS Full-Spectrum Solar Energy System model has been updated and new components have been added. The TPV array and nonimaging device have been tested and progress has been made in the fiber transmission models. A test plan was developed for both the high-lumen tests and the study to determine the non-energy benefits of daylighting. The photobioreactor team also made major advancements in the testing of model scale and bench top lab-scale systems.

  11. Resonance test system

    DOEpatents

    Musial, Walter; White, Darris

    2011-05-31

    An apparatus (10) for applying at least one load to a specimen (12) according to one embodiment of the invention may comprise a mass (18). An actuator (20) mounted to the specimen (12) and operatively associated with the mass (18) moves the mass (18) along a linear displacement path (22) that is perpendicular to a longitudinal axis of the specimen (12). A control system (26) operatively associated with the actuator (20) operates the actuator (20) to reciprocate the mass (18) along the linear displacement path (22) at a reciprocating frequency, the reciprocating frequency being about equal to a resonance frequency of the specimen (12) in a test configuration.

  12. Identifying Differential Item Functioning in Multi-Stage Computer Adaptive Testing

    ERIC Educational Resources Information Center

    Gierl, Mark J.; Lai, Hollis; Li, Johnson

    2013-01-01

    The purpose of this study is to evaluate the performance of CATSIB (Computer Adaptive Testing-Simultaneous Item Bias Test) for detecting differential item functioning (DIF) when items in the matching and studied subtest are administered adaptively in the context of a realistic multi-stage adaptive test (MST). MST was simulated using a 4-item…

  13. SPECTR System Operational Test Report

    SciTech Connect

    W.H. Landman Jr.

    2011-08-01

    This report overviews installation of the Small Pressure Cycling Test Rig (SPECTR) and documents the system operational testing performed to demonstrate that it meets the requirements for operations. The system operational testing involved operation of the furnace system to the design conditions and demonstration of the test article gas supply system using a simulated test article. The furnace and test article systems were demonstrated to meet the design requirements for the Next Generation Nuclear Plant. Therefore, the system is deemed acceptable and is ready for actual test article testing.

  14. MACAO-VLTI adaptive optics systems performance

    NASA Astrophysics Data System (ADS)

    Arsenault, Robin; Donaldson, Rob; Dupuy, Christophe; Fedrigo, Enrico; Hubin, Norbert N.; Ivanescu, Liviu; Kasper, Markus E.; Oberti, Sylvain; Paufique, Jerome; Rossi, Silvio; Silber, Armin; Delabre, Bernhard; Lizon, Jean-Louis; Gigan, Pierre

    2004-10-01

    In April and August "03 two MACAO-VLTI curvature AO systems were installed on the VLT telescopes unit 2 and 3 in Paranal (Chile). These are 60 element systems using a 150mm bimorph deformable mirror and 60 APD"s as WFS detectors. Valuable integration & commissioning experience has been gained during these 2 missions. Several tests have been performed in order to evaluate system performance on the sky. The systems have proven to be extremely robust, performing in a stable fashion in extreme seeing condition (seeing up to 3"). Strehl ratio of 0.65 and residual tilt smaller than 10 mas have been obtained on the sky in 0.8" seeing condition. Weak guide source performance is also excellent with a strehl of 0.26 on a V~16 magnitude star. Several functionalities have been successfully tested including: chopping, off-axis guiding, atmospheric refraction compensation etc. The AO system can be used in a totally automatic fashion with a small overhead: the AO loop can be closed on the target less than 60 sec after star acquisition by the telescope. It includes reading the seeing value given by the site monitor, evaluate the guide star magnitude (cycling through neutral density filters) setting the close-loop AO parameters (system gain and vibrating membrane mirror stroke) including calculation of the command-matrix. The last 2 systems will be installed in August "04 and in the course of 2005.

  15. Improvements on adaptive optics control approaches: experimental tests of wavefront correction forecasting

    NASA Astrophysics Data System (ADS)

    Del Moro, Dario; Piazzesi, Roberto; Stangalini, Marco; Giovannelli, Luca; Berrilli, Francesco

    2015-01-01

    The FORS (closed loop forecasting system) control algorithm has been already successfully applied to improve the efficiency of a simulated adaptive optics (AO) system. To test its performance in real conditions, we implemented this algorithm in a hardware AO demonstrator, introducing controlled aberrations into the system. We present here the results of introducing into the system both a simple periodic defocus aberration and a real open loop defocus time sequence acquired at the vacuum tower telescope solar telescope. In both cases, FORS yields a significant performance increase, improving the stability of the system in closed-loop conditions and decreasing the amplitude of the residual uncorrected wavefront aberrations.

  16. Cross-Layer Self-Adaptive/Self-Aware System Software for Exascale Systems

    SciTech Connect

    Gioiosa, Roberto; Kestor, Gokcen; Kerbyson, Darren J.; Hoisie, Adolfy

    2014-10-22

    The extreme level of parallelism coupled with the limited available power budget expected in the exascale era brings unprecedented challenges that demand optimization of performance, power and resiliency in unison. Scalability on such systems is of paramount importance, while power and reliability issues may change the execution environment in which a parallel application runs. To solve these challenges exascale systems will require an introspective system software that combines system and application observations across all system stack layers with online feedback and adaptation mechanisms. In this paper we propose the design of a novel self-aware, self-adaptive system software in which a kernel-level Monitor, which continuously inspects the evolution of the target system through observation of Sensors, is combined with a user-level Controller, which reacts to changes in the execution environment, explores opportunities to increase performance, save power and adapts applications to new execution scenarios. We show that the monitoring system accurately monitors the evolution of parallel applications with a runtime overhead below 1-2%. As a test case, we design and implement a user-runtime system that aims at optimizing application’s performance and system power consumption on complex hierarchical architectures. Our results show that our adaptive system reaches 98% of performance efficiency of manually-tuned applications.

  17. Telemetry processing for satellite test systems

    NASA Astrophysics Data System (ADS)

    Montiel, Jean Jacques; Khouri, Noel

    The telemetry processing strategy of the MATRA ground test systems is described. The following issues are discussed: signal processing, telemetry parameter definition and access capabilities, data acquisition and monitoring, utilization and archiving of results, and the man-machine interface. It is concluded that the highly modular hardware and software architecture of these systems makes it possible to adapt them to the specific features of different programs and facilitates new standards of telemetry.

  18. Energy Systems Test Area (ESTA). Power Systems Test Facilities

    NASA Technical Reports Server (NTRS)

    Situ, Cindy H.

    2010-01-01

    This viewgraph presentation provides a detailed description of the Johnson Space Center's Power Systems Facility located in the Energy Systems Test Area (ESTA). Facilities and the resources used to support power and battery systems testing are also shown. The contents include: 1) Power Testing; 2) Power Test Equipment Capabilities Summary; 3) Source/Load; 4) Battery Facilities; 5) Battery Test Equipment Capabilities Summary; 6) Battery Testing; 7) Performance Test Equipment; 8) Battery Test Environments; 9) Battery Abuse Chambers; 10) Battery Abuse Capabilities; and 11) Battery Test Area Resources.

  19. Adaptive control of systems with unknown time delays

    NASA Astrophysics Data System (ADS)

    Nelson, James P.

    Control systems, on earth or in outer-space, may exhibit time delays in their dynamic behavior. Aerospace control systems must be able to operate in the presence of time delays both internal to the system and in its inputs and outputs. These delays are often introduced via systems controlled through a network, by information, energy or mass transport phenomena, but can also be caused by computer processing time or by the accumulation of time lags in a number of simple dynamic systems connected in series. When a dynamic system is subject to a time delay, unlike other parameters, this affects the temporal characteristics of the system and exact control over system operation cannot be strictly implemented. Systems with significant time delays are difficult to control using standard feedback controllers. The United States Air Force Research Laboratory (AFRL) is considering the use of router-based data networks on-board next generation satellites and in decentralized control architectures. This approach has the potential to introduce non-constant and non-deterministic communications delays into feedback control loops that make use of these data networks. The desire for rapid deployment of new spacecraft architectures will also introduce many other control issues as the rigorous measurement, calibration and performance tests usually conducted on spacecraft systems to develop a highly precise dynamic model will need to be drastically shortened due to the desired abbreviated build and launch schedule. Due to limited testing and system identification, the spacecraft model will have uncertainties/perturbations from the actual plant. This will require a controller that can robustly control the non-linear dynamic model with limited plant knowledge. The problems created by the control of time delay systems and the limited plant knowledge nature of the systems of interest leads us to the concept of adaptive control. Adaptive control makes adjustment of the controllers

  20. Highly adaptive tests for group differences in brain functional connectivity.

    PubMed

    Kim, Junghi; Pan, Wei

    2015-01-01

    Resting-state functional magnetic resonance imaging (rs-fMRI) and other technologies have been offering evidence and insights showing that altered brain functional networks are associated with neurological illnesses such as Alzheimer's disease. Exploring brain networks of clinical populations compared to those of controls would be a key inquiry to reveal underlying neurological processes related to such illnesses. For such a purpose, group-level inference is a necessary first step in order to establish whether there are any genuinely disrupted brain subnetworks. Such an analysis is also challenging due to the high dimensionality of the parameters in a network model and high noise levels in neuroimaging data. We are still in the early stage of method development as highlighted by Varoquaux and Craddock (2013) that "there is currently no unique solution, but a spectrum of related methods and analytical strategies" to learn and compare brain connectivity. In practice the important issue of how to choose several critical parameters in estimating a network, such as what association measure to use and what is the sparsity of the estimated network, has not been carefully addressed, largely because the answers are unknown yet. For example, even though the choice of tuning parameters in model estimation has been extensively discussed in the literature, as to be shown here, an optimal choice of a parameter for network estimation may not be optimal in the current context of hypothesis testing. Arbitrarily choosing or mis-specifying such parameters may lead to extremely low-powered tests. Here we develop highly adaptive tests to detect group differences in brain connectivity while accounting for unknown optimal choices of some tuning parameters. The proposed tests combine statistical evidence against a null hypothesis from multiple sources across a range of plausible tuning parameter values reflecting uncertainty with the unknown truth. These highly adaptive tests are not only

  1. Highly adaptive tests for group differences in brain functional connectivity

    PubMed Central

    Kim, Junghi; Pan, Wei

    2015-01-01

    Resting-state functional magnetic resonance imaging (rs-fMRI) and other technologies have been offering evidence and insights showing that altered brain functional networks are associated with neurological illnesses such as Alzheimer's disease. Exploring brain networks of clinical populations compared to those of controls would be a key inquiry to reveal underlying neurological processes related to such illnesses. For such a purpose, group-level inference is a necessary first step in order to establish whether there are any genuinely disrupted brain subnetworks. Such an analysis is also challenging due to the high dimensionality of the parameters in a network model and high noise levels in neuroimaging data. We are still in the early stage of method development as highlighted by Varoquaux and Craddock (2013) that “there is currently no unique solution, but a spectrum of related methods and analytical strategies” to learn and compare brain connectivity. In practice the important issue of how to choose several critical parameters in estimating a network, such as what association measure to use and what is the sparsity of the estimated network, has not been carefully addressed, largely because the answers are unknown yet. For example, even though the choice of tuning parameters in model estimation has been extensively discussed in the literature, as to be shown here, an optimal choice of a parameter for network estimation may not be optimal in the current context of hypothesis testing. Arbitrarily choosing or mis-specifying such parameters may lead to extremely low-powered tests. Here we develop highly adaptive tests to detect group differences in brain connectivity while accounting for unknown optimal choices of some tuning parameters. The proposed tests combine statistical evidence against a null hypothesis from multiple sources across a range of plausible tuning parameter values reflecting uncertainty with the unknown truth. These highly adaptive tests are not

  2. Mutual Information Item Selection Method in Cognitive Diagnostic Computerized Adaptive Testing with Short Test Length

    ERIC Educational Resources Information Center

    Wang, Chun

    2013-01-01

    Cognitive diagnostic computerized adaptive testing (CD-CAT) purports to combine the strengths of both CAT and cognitive diagnosis. Cognitive diagnosis models aim at classifying examinees into the correct mastery profile group so as to pinpoint the strengths and weakness of each examinee whereas CAT algorithms choose items to determine those…

  3. Influence of Fallible Item Parameters on Test Information During Adaptive Testing.

    ERIC Educational Resources Information Center

    Wetzel, C. Douglas; McBride, James R.

    Computer simulation was used to assess the effects of item parameter estimation errors on different item selection strategies used in adaptive and conventional testing. To determine whether these effects reduced the advantages of certain optimal item selection strategies, simulations were repeated in the presence and absence of item parameter…

  4. Adapt

    NASA Astrophysics Data System (ADS)

    Bargatze, L. F.

    2015-12-01

    Active Data Archive Product Tracking (ADAPT) is a collection of software routines that permits one to generate XML metadata files to describe and register data products in support of the NASA Heliophysics Virtual Observatory VxO effort. ADAPT is also a philosophy. The ADAPT concept is to use any and all available metadata associated with scientific data to produce XML metadata descriptions in a consistent, uniform, and organized fashion to provide blanket access to the full complement of data stored on a targeted data server. In this poster, we present an application of ADAPT to describe all of the data products that are stored by using the Common Data File (CDF) format served out by the CDAWEB and SPDF data servers hosted at the NASA Goddard Space Flight Center. These data servers are the primary repositories for NASA Heliophysics data. For this purpose, the ADAPT routines have been used to generate data resource descriptions by using an XML schema named Space Physics Archive, Search, and Extract (SPASE). SPASE is the designated standard for documenting Heliophysics data products, as adopted by the Heliophysics Data and Model Consortium. The set of SPASE XML resource descriptions produced by ADAPT includes high-level descriptions of numerical data products, display data products, or catalogs and also includes low-level "Granule" descriptions. A SPASE Granule is effectively a universal access metadata resource; a Granule associates an individual data file (e.g. a CDF file) with a "parent" high-level data resource description, assigns a resource identifier to the file, and lists the corresponding assess URL(s). The CDAWEB and SPDF file systems were queried to provide the input required by the ADAPT software to create an initial set of SPASE metadata resource descriptions. Then, the CDAWEB and SPDF data repositories were queried subsequently on a nightly basis and the CDF file lists were checked for any changes such as the occurrence of new, modified, or deleted

  5. Hypnotizability and Performance on a Prism Adaptation Test.

    PubMed

    Menzocchi, Manuel; Mecacci, Giulio; Zeppi, Andrea; Carli, Giancarlo; Santarcangelo, Enrica L

    2015-12-01

    The susceptibility to hypnosis, which can be measured by scales, is not merely a cognitive trait. In fact, it is associated with a number of physiological correlates in the ordinary state of consciousness and in the absence of suggestions. The hypnotizability-related differences observed in sensorimotor integration suggested a major role of the cerebellum in the peculiar performance of healthy subjects with high scores of hypnotic susceptibility (highs). In order to provide behavioral evidence of this hypothesis, we submitted 20 highs and 21 low hypnotizable participants (lows) to the classical cerebellar Prism Adaptation Test (PAT). We found that the highs' performance was significantly less accurate and more variable than the lows' one, even though the two groups shared the same characteristics of adaptation to prismatic lenses. Although further studies are required to interpret these findings, they could account for earlier reports of hypnotizability-related differences in postural control and blink rate, as they indicate that hypnotizability influences the cerebellar control of sensorimotor integration. PMID:25913127

  6. Adaptive optical system for astronomical applications

    NASA Astrophysics Data System (ADS)

    Merkle, F.; Bille, J.; Freischlad, K.; Frieben, M.; Jahn, G.; Reischmann, H.-L.

    The active optical system being developed for use with the 0.75-m RC telescope at the Landessternwarte in Heidelberg, FRG, is discussed. A 5-cm electrostatically deformable aluminum-coated polymer mirror (sensitivity 0.05 microns/V, maximum local tilt 3 microns/5 mm) is mounted in a gimbal with piezoelectric-actuator tilt control. The mirror control systems being tested are a modified shearing interferometer with crosstalk-compensated feedback and Fourier-modulus wavefront computation, both using a 32 x 32 diode array as detector. Modal phase compensation is achieved using Zernike polynomials and Karhunen-Loeve functions; the correction for the tilt terms of the series expansion is left to the overall-tilt compensation unit, for which preliminary test results are shown.

  7. Network adaptable information systems for safeguard applications

    SciTech Connect

    Rodriguez, C.; Burczyk, L.; Chare, P.; Wagner, H.

    1996-09-01

    While containment and surveillance systems designed for nuclear safeguards have greatly improved through advances in computer, sensor, and microprocessor technologies, the authors recognize the need to continue the advancement of these systems to provide more standardized solutions for safeguards applications of the future. The benefits to be gained from the use of standardized technologies are becoming evident as safeguard activities are increasing world-wide while funding of these activities is becoming more limited. The EURATOM Safeguards Directorate and Los Alamos National Laboratory are developing and testing advanced monitoring technologies coupled with the most efficient solutions for the safeguards applications of the future.

  8. Computerized Adaptive Testing Simulations Using Real Test Taker Responses. Law School Admission Council Computerized Testing Report. LSAC Research Report Series.

    ERIC Educational Resources Information Center

    Wang, Xiang Bo; Pan, WeiQin; Harris, Vincent

    A considerable amount of data on computerized adaptive testing (CAT) has been conducted using simulated data. However, most researchers would agree that simulations may not fully reflect the reality of examinee performance on a test. This study used maximum likelihood procedures to investigate the accuracy and efficiency of examinee ability…

  9. Test Anxiety and Test Performance: Comparing Paper-based and Computer-Adaptive Versions of the Graduate Record Examinations (GRE) General Test.

    ERIC Educational Resources Information Center

    Powers, Donald E.

    2001-01-01

    Tests the hypothesis that the introduction of computer-adaptive testing may help to alleviate test anxiety and diminish the relationship between test anxiety and test performance. Compares a sample of Graduate Record Examinations (GRE) General Test takers who took the computer-adaptive version of the test with another sample who took the…

  10. Implementation of an Adaptive Learning System Using a Bayesian Network

    ERIC Educational Resources Information Center

    Yasuda, Keiji; Kawashima, Hiroyuki; Hata, Yoko; Kimura, Hiroaki

    2015-01-01

    An adaptive learning system is proposed that incorporates a Bayesian network to efficiently gauge learners' understanding at the course-unit level. Also, learners receive content that is adapted to their measured level of understanding. The system works on an iPad via the Edmodo platform. A field experiment using the system in an elementary school…

  11. Isoplanatism in a multiconjugate adaptive optics system.

    PubMed

    Tokovinin, A; Le Louarn, M; Sarazin, M

    2000-10-01

    Turbulence correction in a large field of view by use of an adaptive optics imaging system with several deformable mirrors (DM's) conjugated to various heights is considered. The residual phase variance is computed for an optimized linear algorithm in which a correction of each turbulent layer is achieved by applying a combination of suitably smoothed and scaled input phase screens to all DM's. Finite turbulence outer scale and finite spatial resolution of the DM's are taken into account. A general expression for the isoplanatic angle thetaM of a system with M mirrors is derived in the limiting case of infinitely large apertures and Kolmogorov turbulence. Like Fried's isoplanatic angle theta0,thetaM is a function only of the turbulence vertical profile, is scalable with wavelength, and is independent of the telescope diameter. Use of angle thetaM permits the gain in the field of view due to the increased number of DM's to be quantified and their optimal conjugate heights to be found. Calculations with real turbulence profiles show that with three DM's a gain of 7-10x is possible, giving the typical and best isoplanatic field-of-view radii of 16 and 30 arcseconds, respectively, at lambda = 0.5 microm. It is shown that in the actual systems the isoplanatic field will be somewhat larger than thetaM owing to the combined effects of finite aperture diameter, finite outer scale, and optimized wave-front spatial filtering. However, this additional gain is not dramatic; it is less than 1.5x for large-aperture telescopes. PMID:11028530

  12. The Lethality Test System

    NASA Astrophysics Data System (ADS)

    Parsons, W. M.; Sims, J. R.; Parker, J. V.

    1986-11-01

    The Lethality Test System (LTS) under construction at Los Alamos is an electromagnetic launcher facility designed to perform impact experiments at velocities up to 15 km/sec. The launcher is a 25 mm round bore, plasma armature railgun 22 m in length. Preinjection is accomplished with a two-stage light gas gun capable of 7 km/sec. The railgun power supply utilizes traction motors, vacuum interrupters, and pulse transformers. An assembly of 28 traction motors, equipped with flywheels, stores approximately 80 MJ at 92 percent of full speed and energizes the primary windings of three pulse transformers at a current of 50 kA. At peak current an array of vacuum interrupters disconnects the transformer primary windings and forces the current to flow in the secondary windings. The secondary windings are connected to the railgun, and by staging the vacuum interrupter openings, a 1-1.3 MA ramped current waveform will be delivered to the railgun.

  13. Lethality test system

    SciTech Connect

    Parsons, W.M.; Sims, J.R.; Parker, J.V.

    1986-01-01

    The Lethality Test System (LTS), presently under construction at Los Alamos, is an electromagnetic launcher facility designed to perform impact experiments at velocities up to 15 km/s. The launcher is a 25 mm round bore, plasma armature railgun extending 22 m in length. Preinjection is accomplished with a two-stage gas gun capable of 7 km/s. The railgun power supply utilizes traction motors, vacuum interrupters, and pulse transformers. An assembly of 28 traction motors, equipped with flywheels, stores approximately 80 MJ at 92% of full speed and energizes the primary windings of three pulse transformers at a current of 50 kA. At peak current an array of vacuum interrupters disconnects the transformer primary windings and forces the current to flow in the secondary windings. The secondary windings are connected to the railgun, and by staging the vacuum interrupter openings, a 1 MA to 1.3 MA ramped current waveform will be delivered to the railgun.

  14. Valuation of design adaptability in aerospace systems

    NASA Astrophysics Data System (ADS)

    Fernandez Martin, Ismael

    As more information is brought into early stages of the design, more pressure is put on engineers to produce a reliable, high quality, and financially sustainable product. Unfortunately, requirements established at the beginning of a new project by customers, and the environment that surrounds them, continue to change in some unpredictable ways. The risk of designing a system that may become obsolete during early stages of production is currently tackled by the use of robust design simulation, a method that allows to simultaneously explore a plethora of design alternatives and requirements with the intention of accounting for uncertain factors in the future. Whereas this design technique has proven to be quite an improvement in design methods, under certain conditions, it fails to account for the change of uncertainty over time and the intrinsic value embedded in the system when certain design features are activated. This thesis introduces the concepts of adaptability and real options to manage risk foreseen in the face of uncertainty at early design stages. The method described herein allows decision-makers to foresee the financial impact of their decisions at the design level, as well as the final exposure to risk. In this thesis, cash flow models, traditionally used to obtain the forecast of a project's value over the years, were replaced with surrogate models that are capable of showing fluctuations on value every few days. This allowed a better implementation of real options valuation, optimization, and strategy selection. Through the option analysis model, an optimization exercise allows the user to obtain the best implementation strategy in the face of uncertainty as well as the overall value of the design feature. Here implementation strategy refers to the decision to include a new design feature in the system, after the design has been finalized, but before the end of its production life. The ability to do this in a cost efficient manner after the system

  15. Design, realization and structural testing of a compliant adaptable wing

    NASA Astrophysics Data System (ADS)

    Molinari, G.; Quack, M.; Arrieta, A. F.; Morari, M.; Ermanni, P.

    2015-10-01

    This paper presents the design, optimization, realization and testing of a novel wing morphing concept, based on distributed compliance structures, and actuated by piezoelectric elements. The adaptive wing features ribs with a selectively compliant inner structure, numerically optimized to achieve aerodynamically efficient shape changes while simultaneously withstanding aeroelastic loads. The static and dynamic aeroelastic behavior of the wing, and the effect of activating the actuators, is assessed by means of coupled 3D aerodynamic and structural simulations. To demonstrate the capabilities of the proposed morphing concept and optimization procedure, the wings of a model airplane are designed and manufactured according to the presented approach. The goal is to replace conventional ailerons, thus to achieve controllability in roll purely by morphing. The mechanical properties of the manufactured components are characterized experimentally, and used to create a refined and correlated finite element model. The overall stiffness, strength, and actuation capabilities are experimentally tested and successfully compared with the numerical prediction. To counteract the nonlinear hysteretic behavior of the piezoelectric actuators, a closed-loop controller is implemented, and its capability of accurately achieving the desired shape adaptation is evaluated experimentally. Using the correlated finite element model, the aeroelastic behavior of the manufactured wing is simulated, showing that the morphing concept can provide sufficient roll authority to allow controllability of the flight. The additional degrees of freedom offered by morphing can be also used to vary the plane lift coefficient, similarly to conventional flaps. The efficiency improvements offered by this technique are evaluated numerically, and compared to the performance of a rigid wing.

  16. Applying well flow adapted filtering to transient pumping tests

    NASA Astrophysics Data System (ADS)

    Zech, Alraune; Attinger, Sabine

    2014-05-01

    Transient pumping tests are often used to estimate porous medium characteristics like hydraulic conductivity and storativity. The interpretation of pumping test drawdowns is based on methods which are normally developed under the assumption of homogeneous porous media. However aquifer heterogeneity strongly impacts on well flow pattern, in particular in the vicinity of the pumping well. The purpose of this work is to present a method to interpret drawdowns of transient pumping tests in heterogeneous porous media. With this method we are able to describe the effects that statistical quantities like variance and correlation length have on pumping test drawdowns. Furthermore it allows inferring on the statistical parameters of aquifer heterogeneity from drawdown data by invers estimation, which is not possible using methods for homogeneous media like Theis' solution. The method is based on a representative description of hydraulic conductivity for radial flow regimes. It is derived from a well flow adapted filtering procedure (Coarse Graining), where the heterogeneity of hydraulic conductivity is assumed to be log-normal distributed with a Gaussian correlation structure. applying the up scaled hydraulic conductivity to the groundwater flow equation results in a hydraulic head which depends on the statistical parameters of the porous medium. It describes the drawdown of a transient pumping test in heterogeneous media. We used an ensemble of transient pumping test simulations to verify the up scaled drawdown solution. We generated transient pumping tests in heterogeneous media for various values of the statistical parameters variance and correlation length and evaluated their impact on the drawdown behavior as well as on the temporal evolution. We further examined the impact of several aspects like the location of an observation well or the local conductivity at the pumping well on the drawdown behavior. This work can be understood as an expansion of the work of Zech et

  17. Aircraft as adaptive nonlinear system which must be in the adaptational maximum zone for safety

    SciTech Connect

    Ignative, M.; Simatos, N.; Sivasundaram, S.

    1994-12-31

    Safety is a main problem in aircraft. We are considering this problem from the point of view related to existence of the adaptational maximum in complex developing systems. Safety space of aircraft parameters are determined. This space is transformed to different regimes of flight, when one engine malfunctions etc., are considered. Also it is shown that maximum safety is in adaptational maximum zone.

  18. Network and adaptive system of systems modeling and analysis.

    SciTech Connect

    Lawton, Craig R.; Campbell, James E. Dr.; Anderson, Dennis James; Eddy, John P.

    2007-05-01

    This report documents the results of an LDRD program entitled ''Network and Adaptive System of Systems Modeling and Analysis'' that was conducted during FY 2005 and FY 2006. The purpose of this study was to determine and implement ways to incorporate network communications modeling into existing System of Systems (SoS) modeling capabilities. Current SoS modeling, particularly for the Future Combat Systems (FCS) program, is conducted under the assumption that communication between the various systems is always possible and occurs instantaneously. A more realistic representation of these communications allows for better, more accurate simulation results. The current approach to meeting this objective has been to use existing capabilities to model network hardware reliability and adding capabilities to use that information to model the impact on the sustainment supply chain and operational availability.

  19. Adaptive structures to enable ground test validation of precision structures

    NASA Technical Reports Server (NTRS)

    Wada, Ben K.; Fanson, James F.; Chen, Gun-Shing; Kuo, Chin-Po

    1990-01-01

    The use of analytical models and ground-based experimental validation of precision space structures is addressed. The application of adaptive structures to such validation of precision space structures is addressed, with the focus on adaptive truss structures.

  20. Design and Preliminary Testing of the International Docking Adapter's Peripheral Docking Target

    NASA Technical Reports Server (NTRS)

    Foster, Christopher W.; Blaschak, Johnathan; Eldridge, Erin A.; Brazzel, Jack P.; Spehar, Peter T.

    2015-01-01

    The International Docking Adapter's Peripheral Docking Target (PDT) was designed to allow a docking spacecraft to judge its alignment relative to the docking system. The PDT was designed to be compatible with relative sensors using visible cameras, thermal imagers, or Light Detection and Ranging (LIDAR) technologies. The conceptual design team tested prototype designs and materials to determine the contrast requirements for the features. This paper will discuss the design of the PDT, the methodology and results of the tests, and the conclusions pertaining to PDT design that were drawn from testing.

  1. Central nervous system adaptation to exercise training

    NASA Astrophysics Data System (ADS)

    Kaminski, Lois Anne

    Exercise training causes physiological changes in skeletal muscle that results in enhanced performance in humans and animals. Despite numerous studies on exercise effects on skeletal muscle, relatively little is known about adaptive changes in the central nervous system. This study investigated whether spinal pathways that mediate locomotor activity undergo functional adaptation after 28 days of exercise training. Ventral horn spinal cord expression of calcitonin gene-related peptide (CGRP), a trophic factor at the neuromuscular junction, choline acetyltransferase (Chat), the synthetic enzyme for acetylcholine, vesicular acetylcholine transporter (Vacht), a transporter of ACh into synaptic vesicles and calcineurin (CaN), a protein phosphatase that phosphorylates ion channels and exocytosis machinery were measured to determine if changes in expression occurred in response to physical activity. Expression of these proteins was determined by western blot and immunohistochemistry (IHC). Comparisons between sedentary controls and animals that underwent either endurance training or resistance training were made. Control rats received no exercise other than normal cage activity. Endurance-trained rats were exercised 6 days/wk at 31m/min on a treadmill (8% incline) for 100 minutes. Resistance-trained rats supported their weight plus an additional load (70--80% body weight) on a 60° incline (3 x 3 min, 5 days/wk). CGRP expression was measured by radioimmunoassay (RIA). CGRP expression in the spinal dorsal and ventral horn of exercise-trained animals was not significantly different than controls. Chat expression measured by Western blot and IHC was not significantly different between runners and controls but expression in resistance-trained animals assayed by IHC was significantly less than controls and runners. Vacht and CaN immunoreactivity in motor neurons of endurance-trained rats was significantly elevated relative to control and resistance-trained animals. Ventral

  2. A testing system for CUORE preamplifier production

    NASA Astrophysics Data System (ADS)

    Liu, Xiaohua; Cuore Collaboration

    2011-04-01

    A testing system has been developed for the quality control of the production of the preamplifier for CUORE experiment. There are a total of 988 channels for the readout of CUORE TeO2 crystal bolometers. The preamplifier has a JFET pair at input stage, a gain of 202V/V, very low noise, adjustable common mode rejection ratio, a circuit for the compensation of the detector bias and the offset of JFET pair. The testing system can verify the functions and measure the characteristics to ensure the preamplifiers meet the specifications. The testing system consists of a test carrier board, a bandpass filter board, low noise power supplies, digital control adapters, a data acquisition (DAQ) system and test software based on MATLAB. A test procedure has been developed to configure the devices and test circuits, to control DAQ board to generate the stimulus signal and to acquire the response signal, to analyze the acquired data and store the test result. A web database has also been developed to store the test result. We will present the CUORE electronics testing system and discuss test result from the preamplifier production. UCLA for CUORE Collaboration

  3. Flight Test of L1 Adaptive Control Law: Offset Landings and Large Flight Envelope Modeling Work

    NASA Technical Reports Server (NTRS)

    Gregory, Irene M.; Xargay, Enric; Cao, Chengyu; Hovakimyan, Naira

    2011-01-01

    This paper presents new results of a flight test of the L1 adaptive control architecture designed to directly compensate for significant uncertain cross-coupling in nonlinear systems. The flight test was conducted on the subscale turbine powered Generic Transport Model that is an integral part of the Airborne Subscale Transport Aircraft Research system at the NASA Langley Research Center. The results presented include control law evaluation for piloted offset landing tasks as well as results in support of nonlinear aerodynamic modeling and real-time dynamic modeling of the departure-prone edges of the flight envelope.

  4. A framework for constructing adaptive and reconfigurable systems

    SciTech Connect

    Poirot, Pierre-Etienne; Nogiec, Jerzy; Ren, Shangping; /IIT, Chicago

    2007-05-01

    This paper presents a software approach to augmenting existing real-time systems with self-adaptation capabilities. In this approach, based on the control loop paradigm commonly used in industrial control, self-adaptation is decomposed into observing system events, inferring necessary changes based on a system's functional model, and activating appropriate adaptation procedures. The solution adopts an architectural decomposition that emphasizes independence and separation of concerns. It encapsulates observation, modeling and correction into separate modules to allow for easier customization of the adaptive behavior and flexibility in selecting implementation technologies.

  5. Solderability test system

    DOEpatents

    Yost, Fred; Hosking, Floyd M.; Jellison, James L.; Short, Bruce; Giversen, Terri; Reed, Jimmy R.

    1998-01-01

    A new test method to quantify capillary flow solderability on a printed wiring board surface finish. The test is based on solder flow from a pad onto narrow strips or lines. A test procedure and video image analysis technique were developed for conducting the test and evaluating the data. Feasibility tests revealed that the wetted distance was sensitive to the ratio of pad radius to line width (l/r), solder volume, and flux predry time.

  6. Solderability test system

    DOEpatents

    Yost, F.; Hosking, F.M.; Jellison, J.L.; Short, B.; Giversen, T.; Reed, J.R.

    1998-10-27

    A new test method to quantify capillary flow solderability on a printed wiring board surface finish. The test is based on solder flow from a pad onto narrow strips or lines. A test procedure and video image analysis technique were developed for conducting the test and evaluating the data. Feasibility tests revealed that the wetted distance was sensitive to the ratio of pad radius to line width (l/r), solder volume, and flux predry time. 11 figs.

  7. Comparing Methods of Assessing Differential Item Functioning in a Computerized Adaptive Testing Environment

    ERIC Educational Resources Information Center

    Lei, Pui-Wa; Chen, Shu-Ying; Yu, Lan

    2006-01-01

    Mantel-Haenszel and SIBTEST, which have known difficulty in detecting non-unidirectional differential item functioning (DIF), have been adapted with some success for computerized adaptive testing (CAT). This study adapts logistic regression (LR) and the item-response-theory-likelihood-ratio test (IRT-LRT), capable of detecting both unidirectional…

  8. High-Resolution Adaptive Optics Test-Bed for Vision Science

    SciTech Connect

    Wilks, S C; Thomspon, C A; Olivier, S S; Bauman, B J; Barnes, T; Werner, J S

    2001-09-27

    We discuss the design and implementation of a low-cost, high-resolution adaptive optics test-bed for vision research. It is well known that high-order aberrations in the human eye reduce optical resolution and limit visual acuity. However, the effects of aberration-free eyesight on vision are only now beginning to be studied using adaptive optics to sense and correct the aberrations in the eye. We are developing a high-resolution adaptive optics system for this purpose using a Hamamatsu Parallel Aligned Nematic Liquid Crystal Spatial Light Modulator. Phase-wrapping is used to extend the effective stroke of the device, and the wavefront sensing and wavefront correction are done at different wavelengths. Issues associated with these techniques will be discussed.

  9. Nonequilibrium Enhances Adaptation Efficiency of Stochastic Biochemical Systems

    PubMed Central

    Jia, Chen; Qian, Minping

    2016-01-01

    Adaptation is a crucial biological function possessed by many sensory systems. Early work has shown that some influential equilibrium models can achieve accurate adaptation. However, recent studies indicate that there are close relationships between adaptation and nonequilibrium. In this paper, we provide an explanation of these two seemingly contradictory results based on Markov models with relatively simple networks. We show that as the nonequilibrium driving becomes stronger, the system under consideration will undergo a phase transition along a fixed direction: from non-adaptation to simple adaptation then to oscillatory adaptation, while the transition in the opposite direction is forbidden. This indicates that although adaptation may be observed in equilibrium systems, it tends to occur in systems far away from equilibrium. In addition, we find that nonequilibrium will improve the performance of adaptation by enhancing the adaptation efficiency. All these results provide a deeper insight into the connection between adaptation and nonequilibrium. Finally, we use a more complicated network model of bacterial chemotaxis to validate the main results of this paper. PMID:27195482

  10. Nonequilibrium Enhances Adaptation Efficiency of Stochastic Biochemical Systems.

    PubMed

    Jia, Chen; Qian, Minping

    2016-01-01

    Adaptation is a crucial biological function possessed by many sensory systems. Early work has shown that some influential equilibrium models can achieve accurate adaptation. However, recent studies indicate that there are close relationships between adaptation and nonequilibrium. In this paper, we provide an explanation of these two seemingly contradictory results based on Markov models with relatively simple networks. We show that as the nonequilibrium driving becomes stronger, the system under consideration will undergo a phase transition along a fixed direction: from non-adaptation to simple adaptation then to oscillatory adaptation, while the transition in the opposite direction is forbidden. This indicates that although adaptation may be observed in equilibrium systems, it tends to occur in systems far away from equilibrium. In addition, we find that nonequilibrium will improve the performance of adaptation by enhancing the adaptation efficiency. All these results provide a deeper insight into the connection between adaptation and nonequilibrium. Finally, we use a more complicated network model of bacterial chemotaxis to validate the main results of this paper. PMID:27195482

  11. Performance of the Keck Observatory adaptive optics system

    SciTech Connect

    van Dam, M A; Mignant, D L; Macintosh, B A

    2004-01-19

    In this paper, the adaptive optics (AO) system at the W.M. Keck Observatory is characterized. The authors calculate the error budget of the Keck AO system operating in natural guide star mode with a near infrared imaging camera. By modeling the control loops and recording residual centroids, the measurement noise and band-width errors are obtained. The error budget is consistent with the images obtained. Results of sky performance tests are presented: the AO system is shown to deliver images with average Strehl ratios of up to 0.37 at 1.58 {micro}m using a bright guide star and 0.19 for a magnitude 12 star.

  12. System reliability, performance and trust in adaptable automation.

    PubMed

    Chavaillaz, Alain; Wastell, David; Sauer, Jürgen

    2016-01-01

    The present study examined the effects of reduced system reliability on operator performance and automation management in an adaptable automation environment. 39 operators were randomly assigned to one of three experimental groups: low (60%), medium (80%), and high (100%) reliability of automation support. The support system provided five incremental levels of automation which operators could freely select according to their needs. After 3 h of training on a simulated process control task (AutoCAMS) in which the automation worked infallibly, operator performance and automation management were measured during a 2.5-h testing session. Trust and workload were also assessed through questionnaires. Results showed that although reduced system reliability resulted in lower levels of trust towards automation, there were no corresponding differences in the operators' reliance on automation. While operators showed overall a noteworthy ability to cope with automation failure, there were, however, decrements in diagnostic speed and prospective memory with lower reliability. PMID:26360226

  13. Adapting Mars Entry, Descent and Landing System for Earth

    NASA Astrophysics Data System (ADS)

    Heilimo, J.; Harri, A.-M.; Aleksashkin, S.; Koryanov, V.; Guerrero, H.; Schmidt, W.; Haukka, H.; Finchenko, V.; Martynov, M.; Ostresko, B.; Ponomarenko, A.; Kazakovtsev, V.; Arruego, I.; Martin, S.; Siili, T.

    2013-09-01

    In 2001 - 2011 an inflatable Entry, Descent and Landing System (EDLS) for Martian atmosphere was developed by FMI and the MetNet team. This MetNet Mars Lander EDLS is used in both the initial deceleration during atmospheric entry and in the final deceleration before the semi-hard impact of the penetrator to Martian surface. The EDLS design is ingenious and its applicability to Earth's atmosphere is studied in the on-going project. In particular, the behavior of the system in the critical transonic aerodynamic (from hypersonic to subsonic) regime will be investigated. This project targets to analyze and test the transonic behavior of this compact and light weight payload entry system to Earth's atmosphere [1]. Scaling and adaptation for terrestrial atmospheric conditions, instead of a completely new design, is a favorable approach for providing a new re-entry vehicle for terrestrial space applications.

  14. Variable-Length Computerized Adaptive Testing: Adaptation of the A-Stratified Strategy in Item Selection with Content Balancing

    ERIC Educational Resources Information Center

    Huo, Yan

    2009-01-01

    Variable-length computerized adaptive testing (CAT) can provide examinees with tailored test lengths. With the fixed standard error of measurement ("SEM") termination rule, variable-length CAT can achieve predetermined measurement precision by using relatively shorter tests compared to fixed-length CAT. To explore the application of…

  15. Human identification by FSS system adapted to cephalometric radiographs.

    PubMed

    Rabelo, Katharina Alves; Dos Anjos Pontual, Maria Luiza; de Queiroz Jordão, Nathalie; de Paiva, Kariny Milfont; de Moraes Ramos-Perez, Flavia Maria; Dos Santos, Marcelo Soares; Dos Anjos Pontual, Andrea

    2016-05-01

    The aim of this study was to verify the applicability and reproducibility of the FSS system [8] adapted for frontal and lateral cephalometric radiographs of the frontal sinus for human identification purposes. Eighty lateral and frontal digital cephalometric radiographs from a private Dental Radiology service's database were evaluated. Evaluations were performed in a dimmed lighting room, using a 4.200 lux lightbox with mask, ultrafan paper and pencil with a 0.5 diameter tip. The sheet of paper was superimposed on the radiograph to obtain the outlines of the frontal sinus and two examiners made the drawings independently at two different times, with a minimum period interval between evaluations. To obtain the linear physical measurements of the frontal sinus, a digital pachymeter was used. Later, all the discrete variables were codded for the statistical analysis. All variables were tested by means of the Cohen's Kappa test. The intraexaminer agreement ranged from good to perfect (p<0.001), while the interexaminer agreement ranged from regular to perfect (p<0.001). The use of frontal and lateral cephalometric radiographs was found to be reproducible and reliable for human identification by an adaptation of FSS system. PMID:27045380

  16. Restricted Complexity Framework for Nonlinear Adaptive Control in Complex Systems

    SciTech Connect

    Williams, Rube B.

    2004-02-04

    Control law adaptation that includes implicit or explicit adaptive state estimation, can be a fundamental underpinning for the success of intelligent control in complex systems, particularly during subsystem failures, where vital system states and parameters can be impractical or impossible to measure directly. A practical algorithm is proposed for adaptive state filtering and control in nonlinear dynamic systems when the state equations are unknown or are too complex to model analytically. The state equations and inverse plant model are approximated by using neural networks. A framework for a neural network based nonlinear dynamic inversion control law is proposed, as an extrapolation of prior developed restricted complexity methodology used to formulate the adaptive state filter. Examples of adaptive filter performance are presented for an SSME simulation with high pressure turbine failure to support extrapolations to adaptive control problems.

  17. Restricted Complexity Framework for Nonlinear Adaptive Control in Complex Systems

    NASA Astrophysics Data System (ADS)

    Williams, Rube B.

    2004-02-01

    Control law adaptation that includes implicit or explicit adaptive state estimation, can be a fundamental underpinning for the success of intelligent control in complex systems, particularly during subsystem failures, where vital system states and parameters can be impractical or impossible to measure directly. A practical algorithm is proposed for adaptive state filtering and control in nonlinear dynamic systems when the state equations are unknown or are too complex to model analytically. The state equations and inverse plant model are approximated by using neural networks. A framework for a neural network based nonlinear dynamic inversion control law is proposed, as an extrapolation of prior developed restricted complexity methodology used to formulate the adaptive state filter. Examples of adaptive filter performance are presented for an SSME simulation with high pressure turbine failure to support extrapolations to adaptive control problems.

  18. Aeroelastic Deformation: Adaptation of Wind Tunnel Measurement Concepts to Full-Scale Vehicle Flight Testing

    NASA Technical Reports Server (NTRS)

    Burner, Alpheus W.; Lokos, William A.; Barrows, Danny A.

    2005-01-01

    The adaptation of a proven wind tunnel test technique, known as Videogrammetry, to flight testing of full-scale vehicles is presented. A description is presented of the technique used at NASA's Dryden Flight Research Center for the measurement of the change in wing twist and deflection of an F/A-18 research aircraft as a function of both time and aerodynamic load. Requirements for in-flight measurements are compared and contrasted with those for wind tunnel testing. The methodology for the flight-testing technique and differences compared to wind tunnel testing are given. Measurement and operational comparisons to an older in-flight system known as the Flight Deflection Measurement System (FDMS) are presented.

  19. Adaptive Hypermedia Educational System Based on XML Technologies.

    ERIC Educational Resources Information Center

    Baek, Yeongtae; Wang, Changjong; Lee, Sehoon

    This paper proposes an adaptive hypermedia educational system using XML technologies, such as XML, XSL, XSLT, and XLink. Adaptive systems are capable of altering the presentation of the content of the hypermedia on the basis of a dynamic understanding of the individual user. The user profile can be collected in a user model, while the knowledge…

  20. Concept Based Approach for Adaptive Personalized Course Learning System

    ERIC Educational Resources Information Center

    Salahli, Mehmet Ali; Özdemir, Muzaffer; Yasar, Cumali

    2013-01-01

    One of the most important factors for improving the personalization aspects of learning systems is to enable adaptive properties to them. The aim of the adaptive personalized learning system is to offer the most appropriate learning path and learning materials to learners by taking into account their profiles. In this paper, a new approach to…

  1. Development of Adaptive Kanji Learning System for Mobile Phone

    ERIC Educational Resources Information Center

    Li, Mengmeng; Ogata, Hiroaki; Hou, Bin; Hashimoto, Satoshi; Liu, Yuqin; Uosaki, Noriko; Yano, Yoneo

    2010-01-01

    This paper describes an adaptive learning system based on mobile phone email to support the study of Japanese Kanji. In this study, the main emphasis is on using the adaptive learning to resolve one common problem of the mobile-based email or SMS language learning systems. To achieve this goal, the authors main efforts focus on three aspects:…

  2. Management Strategies for Complex Adaptive Systems: Sensemaking, Learning, and Improvisation

    ERIC Educational Resources Information Center

    McDaniel, Reuben R., Jr.

    2007-01-01

    Misspecification of the nature of organizations may be a major reason for difficulty in achieving performance improvement. Organizations are often viewed as machine-like, but complexity science suggests that organizations should be viewed as complex adaptive systems. I identify the characteristics of complex adaptive systems and give examples of…

  3. Psychological Effects of Immediate Knowledge of Results and Adaptive Ability Testing. Research Report 76-4.

    ERIC Educational Resources Information Center

    Betz, Nancy E.; Weiss, David J.

    The effects of providing immediate knowledge of results (KR) and adaptive testing on test anxiety and test-taking motivation were investigated. Also studied was the accuracy of student perceptions of the difficulty of adaptive and conventional tests administered with or without immediate knowledge of results. Testees were 350 college students…

  4. On the Issue of Item Selection in Computerized Adaptive Testing with Response Times

    ERIC Educational Resources Information Center

    Veldkamp, Bernard P.

    2016-01-01

    Many standardized tests are now administered via computer rather than paper-and-pencil format. The computer-based delivery mode brings with it certain advantages. One advantage is the ability to adapt the difficulty level of the test to the ability level of the test taker in what has been termed computerized adaptive testing (CAT). A second…

  5. Hardware and operating features of the adaptive wall test section for the 0.3-meter transonic cryogenic tunnel

    NASA Technical Reports Server (NTRS)

    Mineck, Raymond E.

    1989-01-01

    A 13- by 13-inch adaptive wall test section was installed in the Langley 0.3-Meter Transonic Cryogenic Tunnel circuit. This test section has four solid walls and is configured for two-dimensional airfoil testing. The top and bottom walls are flexible and movable, whereas the sidwalls are rigid and fixed. The test section has a turntable to support airfoil models, a survey mechanism to probe the model wake, and provisions for a sidewall boundary-layer-control system. Details of the adaptive wall test section, the tunnel circuit modifications, the supporting instrumentation, the monitoring and control hardware, and the wall adaptation strategy are discussed. Sample results of shakedown tests with the test section empty and with an airfoil installed are also included.

  6. Experimental characterization of an adaptive aileron: lab tests and FE correlation

    NASA Astrophysics Data System (ADS)

    Amendola, Gianluca; Dimino, Ignazio; Amoroso, Francesco; Pecora, Rosario

    2016-04-01

    Like any other technology, morphing has to demonstrate system level performance benefits prior to implementation onto a real aircraft. The current status of morphing structures research efforts (as the ones, sponsored by the European Union) involves the design of several subsystems which have to be individually tested in order to consolidate their general performance in view of the final integration into a flyable device. This requires a fundamental understanding of the interaction between aerodynamic, structure and control systems. Important worldwide research collaborations were born in order to exchange acquired experience and better investigate innovative technologies devoted to morphing structures. The "Adaptive Aileron" project represents a joint cooperation between Canadian and Italian research centers and leading industries. In this framework, an overview of the design, manufacturing and testing of a variable camber aileron for a regional aircraft is presented. The key enabling technology for the presented morphing aileron is the actuation structural system, integrating a suitable motor and a load-bearing architecture. The paper describes the lab test campaign of the developed device. The implementation of a distributed actuation system fulfills the actual tendency of the aeronautical research to move toward the use of electrical power to supply non-propulsive systems. The aileron design features are validated by targeted experimental tests, demonstrating both its adaptive capability and robustness under operative loads and its dynamic behavior for further aeroelastic analyses. The experimental results show a satisfactory correlation with the numerical expectations thus validating the followed design approach.

  7. Flight Results of the NF-15B Intelligent Flight Control System (IFCS) Aircraft with Adaptation to a Longitudinally Destabilized Plant

    NASA Technical Reports Server (NTRS)

    Bosworth, John T.

    2008-01-01

    Adaptive flight control systems have the potential to be resilient to extreme changes in airplane behavior. Extreme changes could be a result of a system failure or of damage to the airplane. The goal for the adaptive system is to provide an increase in survivability in the event that these extreme changes occur. A direct adaptive neural-network-based flight control system was developed for the National Aeronautics and Space Administration NF-15B Intelligent Flight Control System airplane. The adaptive element was incorporated into a dynamic inversion controller with explicit reference model-following. As a test the system was subjected to an abrupt change in plant stability simulating a destabilizing failure. Flight evaluations were performed with and without neural network adaptation. The results of these flight tests are presented. Comparison with simulation predictions and analysis of the performance of the adaptation system are discussed. The performance of the adaptation system is assessed in terms of its ability to stabilize the vehicle and reestablish good onboard reference model-following. Flight evaluation with the simulated destabilizing failure and adaptation engaged showed improvement in the vehicle stability margins. The convergent properties of this initial system warrant additional improvement since continued maneuvering caused continued adaptation change. Compared to the non-adaptive system the adaptive system provided better closed-loop behavior with improved matching of the onboard reference model. A detailed discussion of the flight results is presented.

  8. Photovoltaic systems test facility

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Facility provides broad and flexible capability for evaluating photovoltaic systems and design concepts. As 'breadboard' system, it can be used to check out complete systems, subsystems, and components before installation in actual service.

  9. Calibrated Methodology for Assessing Adaptation Costs for Urban Drainage Systems

    EPA Science Inventory

    Changes in precipitation patterns associated with climate change may pose significant challenges for storm water management systems across much of the U.S. In particular, adapting these systems to more intense rainfall events will require significant investment. The assessment ...

  10. Development of a Computerized Adaptive Test for Depression

    PubMed Central

    Gibbons, Robert D.; Weiss, David J.; Pilkonis, Paul A.; Frank, Ellen; Moore, Tara; Kim, Jong Bae; Kupfer, David J.

    2012-01-01

    Context Unlike other areas of medicine, psychiatry is almost entirely dependent on patient report to assess the presence and severity of disease; therefore, it is particularly crucial that we find both more accurate and efficient means of obtaining that report. Objective To develop a computerized adaptive test (CAT) for depression, called the Computerized Adaptive Test–Depression Inventory (CAT-DI), that decreases patient and clinician burden and increases measurement precision. Design Case-control study. Setting A psychiatric clinic and community mental health center. Participants A total of 1614 individuals with and without minor and major depression were recruited for study. Main Outcome Measures The focus of this study was the development of the CAT-DI. The 24-item Hamilton Rating Scale for Depression, Patient Health Questionnaire 9, and the Center for Epidemiologic Studies Depression Scale were used to study the convergent validity of the new measure, and the Structured Clinical Interview for DSM-IV was used to obtain diagnostic classifications of minor and major depressive disorder. Results A mean of 12 items per study participant was required to achieve a 0.3 SE in the depression severity estimate and maintain a correlation of r=0.95 with the total 389-item test score. Using empirically derived thresholds based on a mixture of normal distributions, we found a sensitivity of 0.92 and a specificity of 0.88 for the classification of major depressive disorder in a sample consisting of depressed patients and healthy controls. Correlations on the order of r=0.8 were found with the other clinician and self-rating scale scores. The CAT-DI provided excellent discrimination throughout the entire depressive severity continuum (minor and major depression), whereas the traditional scales did so primarily at the extremes (eg, major depression). Conclusions Traditional measurement fixes the number of items administered and allows measurement uncertainty to vary. In

  11. Test application of Bayesian Programming: Adaptive water quality management under uncertainty

    NASA Astrophysics Data System (ADS)

    Harrison, Kenneth W.

    2007-03-01

    A new method, Bayesian Programming (BP), developed by Harrison [Harrison KW. Multi-stage decision-making under uncertainty and stochasticity: Bayesian Programming. Adv Water Resour, submitted for publication] is tested on a case study involving optimal adaptive management of a river basin. The case study considers anew the process of permitting pulp mills on the Athabasca River in Alberta, Canada. The problem has characteristics common to many environmental management problems. There is uncertainty in the water quality response to pollutant loadings that will not be completely resolved with monitoring and the resolution of this uncertainty is impeded by the stochastic behavior of the water quality system. A two-stage adaptive management process is optimized with BP. Based on monitoring data collected after implementation of the first-stage decision, the uncertainties are updated prior to the second decision stage using Bayesian analysis. The worth of this two-stage adaptive management approach to this problem and the worth of monitoring are evaluated. Conclusions are drawn on the general practicality of BP for adaptive management. Potential strategies are outlined for extending the BP approach to secure further benefits of adaptive management.

  12. Flight Test Comparison of Different Adaptive Augmentations for Fault Tolerant Control Laws for a Modified F-15

    NASA Technical Reports Server (NTRS)

    Burken, John J.; Hanson, Curtis E.; Lee, James A.; Kaneshinge, John T.

    2009-01-01

    This report describes the improvements and enhancements to a neural network based approach for directly adapting to aerodynamic changes resulting from damage or failures. This research is a follow-on effort to flight tests performed on the NASA F-15 aircraft as part of the Intelligent Flight Control System research effort. Previous flight test results demonstrated the potential for performance improvement under destabilizing damage conditions. Little or no improvement was provided under simulated control surface failures, however, and the adaptive system was prone to pilot-induced oscillations. An improved controller was designed to reduce the occurrence of pilot-induced oscillations and increase robustness to failures in general. This report presents an analysis of the neural networks used in the previous flight test, the improved adaptive controller, and the baseline case with no adaptation. Flight test results demonstrate significant improvement in performance by using the new adaptive controller compared with the previous adaptive system and the baseline system for control surface failures.

  13. HIDEC adaptive engine control system flight evaluation results

    NASA Technical Reports Server (NTRS)

    Yonke, W. A.; Landy, R. J.; Stewart, J. F.

    1987-01-01

    An integrated flight propulsion control mode, the Adaptive Engine Control System (ADECS), has been developed and flight tested on an F-15 aircraft as part of the NASA Highly Integrated Digital Electronic Control program. The ADECS system realizes additional engine thrust by increasing the engine pressure ratio (EPR) at intermediate and afterburning power, with the amount of EPR uptrim modulated using a predictor scheme for angle-of-attack and sideslip angle. Substantial improvement in aircraft and engine performance was demonstrated, with a 16 percent rate of climb increase, a 14 percent reduction in time to climb, and a 15 percent reduction in time to accelerate. Significant EPR uptrim capability was found with angles-of-attack up to 20 degrees.

  14. Integrated flight/propulsion control - Adaptive engine control system mode

    NASA Technical Reports Server (NTRS)

    Yonke, W. A.; Terrell, L. A.; Meyers, L. P.

    1985-01-01

    The adaptive engine control system mode (ADECS) which is developed and tested on an F-15 aircraft with PW1128 engines, using the NASA sponsored highly integrated digital electronic control program, is examined. The operation of the ADECS mode, as well as the basic control logic, the avionic architecture, and the airframe/engine interface are described. By increasing engine pressure ratio (EPR) additional thrust is obtained at intermediate power and above. To modulate the amount of EPR uptrim and to prevent engine stall, information from the flight control system is used. The performance benefits, anticipated from control integration are shown for a range of flight conditions and power settings. It is found that at higher altitudes, the ADECS mode can increase thrust as much as 12 percent, which is used for improved acceleration, improved turn rate, or sustained turn angle.

  15. Inherent robustness of discrete-time adaptive control systems

    NASA Technical Reports Server (NTRS)

    Ma, C. C. H.

    1986-01-01

    Global stability robustness with respect to unmodeled dynamics, arbitrary bounded internal noise, as well as external disturbance is shown to exist for a class of discrete-time adaptive control systems when the regressor vectors of these systems are persistently exciting. Although fast adaptation is definitely undesirable, so far as attaining the greatest amount of global stability robustness is concerned, slow adaptation is shown to be not necessarily beneficial. The entire analysis in this paper holds for systems with slowly varying return difference matrices; the plants in these systems need not be slowly varying.

  16. Hormesis and adaptive cellular control systems

    EPA Science Inventory

    Hormetic dose response occurs for many endpoints associated with exposures of biological organisms to environmental stressors. Cell-based U- or inverted U-shaped responses may derive from common processes involved in activation of adaptive responses required to protect cells from...

  17. Adaptive Learning Systems: Beyond Teaching Machines

    ERIC Educational Resources Information Center

    Kara, Nuri; Sevim, Nese

    2013-01-01

    Since 1950s, teaching machines have changed a lot. Today, we have different ideas about how people learn, what instructor should do to help students during their learning process. We have adaptive learning technologies that can create much more student oriented learning environments. The purpose of this article is to present these changes and its…

  18. A self-adaptive feedforward rf control system for linacs

    NASA Astrophysics Data System (ADS)

    Zhang, Renshan; Ben-Zvi, Ilan; Xie, Jialin

    1993-01-01

    The design and performance of a self-adaptive feedforward rf control system are reported. The system was built for the linac of the Accelerator Test Facility (ATF) at Brookhaven National Laboratory. Variables of time along the linac macropulse, such as field or phase are discretized and represented as vectors. Upon turn-on or after a large change in the operating-point, the control system acquires the response of the system to test signal vectors and generates a linearized system response matrix. During operation an error vector is generated by comparing the linac variable vectors and a target vector. The error vector is multiplied by the inverse of the system's matrix to generate a correction vector is added to an operating point vector. This control system can be used to control a klystron to produce flat rf amplitude and phase pulses, to control a rf cavity to reduce the rf field fluctuation, and to compensate the energy spread among bunches in a rf linac. Beam loading effects can be corrected and a programmed ramp can be produced. The performance of the control system has been evaluated on the control of a klystron's output as well as an rf cavity. Both amplitude and phase have been regulated simultaneously. In initial tests, the rf output from a klystron has been regulated to an amplitude fluctuation of less than ±0.3% and phase variation of less than ±0.6°. The rf field of the ATF's photo-cathode microwave gun cavity has been regulated to ±0.5% in amplitude and simultaneously to ±1° in phase. Regulating just the rf field amplitude in the rf gun cavity, we have achieved amplitude fluctuation of less than ±0.2%.

  19. A New Online Calibration Method for Multidimensional Computerized Adaptive Testing.

    PubMed

    Chen, Ping; Wang, Chun

    2016-09-01

    Multidimensional-Method A (M-Method A) has been proposed as an efficient and effective online calibration method for multidimensional computerized adaptive testing (MCAT) (Chen & Xin, Paper presented at the 78th Meeting of the Psychometric Society, Arnhem, The Netherlands, 2013). However, a key assumption of M-Method A is that it treats person parameter estimates as their true values, thus this method might yield erroneous item calibration when person parameter estimates contain non-ignorable measurement errors. To improve the performance of M-Method A, this paper proposes a new MCAT online calibration method, namely, the full functional MLE-M-Method A (FFMLE-M-Method A). This new method combines the full functional MLE (Jones & Jin in Psychometrika 59:59-75, 1994; Stefanski & Carroll in Annals of Statistics 13:1335-1351, 1985) with the original M-Method A in an effort to correct for the estimation error of ability vector that might otherwise adversely affect the precision of item calibration. Two correction schemes are also proposed when implementing the new method. A simulation study was conducted to show that the new method generated more accurate item parameter estimation than the original M-Method A in almost all conditions. PMID:26608960

  20. Systems and Methods for Derivative-Free Adaptive Control

    NASA Technical Reports Server (NTRS)

    Yucelen, Tansel (Inventor); Kim, Kilsoo (Inventor); Calise, Anthony J. (Inventor)

    2015-01-01

    An adaptive control system is disclosed. The control system can control uncertain dynamic systems. The control system can employ one or more derivative-free adaptive control architectures. The control system can further employ one or more derivative-free weight update laws. The derivative-free weight update laws can comprise a time-varying estimate of an ideal vector of weights. The control system of the present invention can therefore quickly stabilize systems that undergo sudden changes in dynamics, caused by, for example, sudden changes in weight. Embodiments of the present invention can also provide a less complex control system than existing adaptive control systems. The control system can control aircraft and other dynamic systems, such as, for example, those with non-minimum phase dynamics.

  1. What We Can Do with Computerized Adaptive Testing...and What We Cannot Do!

    ERIC Educational Resources Information Center

    Laurier, Michel

    Computerized adaptive testing for language teaching and learning takes advantage of two properties of the computer: its number-crunching and multiple-branching capabilities. Adaptive testing has also been called tailored testing because it aims at presenting items that suit the student's competence and that are informative, using an item bank and…

  2. An Investigation on Computer-Adaptive Multistage Testing Panels for Multidimensional Assessment

    ERIC Educational Resources Information Center

    Wang, Xinrui

    2013-01-01

    The computer-adaptive multistage testing (ca-MST) has been developed as an alternative to computerized adaptive testing (CAT), and been increasingly adopted in large-scale assessments. Current research and practice only focus on ca-MST panels for credentialing purposes. The ca-MST test mode, therefore, is designed to gauge a single scale. The…

  3. Micro-tensile testing system

    DOEpatents

    Wenski, Edward G.

    2006-01-10

    A micro-tensile testing system providing a stand-alone test platform for testing and reporting physical or engineering properties of test samples of materials having thicknesses of approximately between 0.002 inch and 0.030 inch, including, for example, LiGA engineered materials. The testing system is able to perform a variety of static, dynamic, and cyclic tests. The testing system includes a rigid frame and adjustable gripping supports to minimize measurement errors due to deflection or bending under load; serrated grips for securing the extremely small test sample; high-speed laser scan micrometers for obtaining accurate results; and test software for controlling the testing procedure and reporting results.

  4. Micro-tensile testing system

    DOEpatents

    Wenski, Edward G.

    2007-08-21

    A micro-tensile testing system providing a stand-alone test platform for testing and reporting physical or engineering properties of test samples of materials having thicknesses of approximately between 0.002 inch and 0.030 inch, including, for example, LiGA engineered materials. The testing system is able to perform a variety of static, dynamic, and cyclic tests. The testing system includes a rigid frame and adjustable gripping supports to minimize measurement errors due to deflection or bending under load; serrated grips for securing the extremely small test sample; high-speed laser scan micrometers for obtaining accurate results; and test software for controlling the testing procedure and reporting results.

  5. Micro-tensile testing system

    DOEpatents

    Wenski, Edward G.

    2007-07-17

    A micro-tensile testing system providing a stand-alone test platform for testing and reporting physical or engineering properties of test samples of materials having thicknesses of approximately between 0.002 inch and 0.030 inch, including, for example, LiGA engineered materials. The testing system is able to perform a variety of static, dynamic, and cyclic tests. The testing system includes a rigid frame and adjustable gripping supports to minimize measurement errors due to deflection or bending under load; serrated grips for securing the extremely small test sample; high-speed laser scan micrometers for obtaining accurate results; and test software for controlling the testing procedure and reporting results.

  6. Adaptive management of social-ecological systems: the path forward

    USGS Publications Warehouse

    Allen, Craig R.

    2015-01-01

    Adaptive management remains at the forefront of environmental management nearly 40 years after its original conception, largely because we have yet to develop other methodologies that offer the same promise. Despite the criticisms of adaptive management and the numerous failed attempts to implement it, adaptive management has yet to be replaced with a better alternative. The concept persists because it is simple, allows action despite uncertainty, and fosters learning. Moving forward, adaptive management of social-ecological systems provides policymakers, managers and scientists a powerful tool for managing for resilience in the face of uncertainty.

  7. Electronics systems test laboratory testing of shuttle communications systems

    NASA Technical Reports Server (NTRS)

    Stoker, C. J.; Bromley, L. K.

    1985-01-01

    Shuttle communications and tracking systems space to space and space to ground compatibility and performance evaluations are conducted in the NASA Johnson Space Center Electronics Systems Test Laboratory (ESTL). This evaluation is accomplished through systems verification/certification tests using orbiter communications hardware in conjunction with other shuttle communications and tracking external elements to evaluate end to end system compatibility and to verify/certify that overall system performance meets program requirements before manned flight usage. In this role, the ESTL serves as a multielement major ground test facility. The ESTL capability and program concept are discussed. The system test philosophy for the complex communications channels is described in terms of the major phases. Results of space to space and space to ground systems tests are presented. Several examples of the ESTL's unique capabilities to locate and help resolve potential problems are discussed in detail.

  8. Averaging analysis for discrete time and sampled data adaptive systems

    NASA Technical Reports Server (NTRS)

    Fu, Li-Chen; Bai, Er-Wei; Sastry, Shankar S.

    1986-01-01

    Earlier continuous time averaging theorems are extended to the nonlinear discrete time case. Theorems for the study of the convergence analysis of discrete time adaptive identification and control systems are used. Instability theorems are also derived and used for the study of robust stability and instability of adaptive control schemes applied to sampled data systems. As a by product, the effects of sampling on unmodeled dynamics in continuous time systems are also studied.

  9. Adaptive control applied to Space Station attitude control system

    NASA Technical Reports Server (NTRS)

    Lam, Quang M.; Chipman, Richard; Hu, Tsay-Hsin G.; Holmes, Eric B.; Sunkel, John

    1992-01-01

    This paper presents an adaptive control approach to enhance the performance of current attitude control system used by the Space Station Freedom. The proposed control law was developed based on the direct adaptive control or model reference adaptive control scheme. Performance comparisons, subject to inertia variation, of the adaptive controller and the fixed-gain linear quadratic regulator currently implemented for the Space Station are conducted. Both the fixed-gain and the adaptive gain controllers are able to maintain the Station stability for inertia variations of up to 35 percent. However, when a 50 percent inertia variation is applied to the Station, only the adaptive controller is able to maintain the Station attitude.

  10. Effects of Informed Item Selection on Test Performance and Anxiety for Examinees Administered a Self-Adapted Test.

    ERIC Educational Resources Information Center

    Plake, Barbara S.; And Others

    1995-01-01

    No significant differences in performance on a self-adapted test or anxiety were found for college students (n=218) taking a self-adapted test who selected item difficulty without any prior information, inspected an item before selecting, or answered a typical item and received performance feedback. (SLD)

  11. A low-cost compact metric adaptive optics system

    NASA Astrophysics Data System (ADS)

    Mansell, Justin D.; Henderson, Brian; Wiesner, Brennen; Praus, Robert; Coy, Steve

    2007-09-01

    The application of adaptive optics has been hindered by the cost, size, and complexity of the systems. We describe here progress we have made toward creating low-cost compact turn-key adaptive optics systems. We describe our new low-cost deformable mirror technology developed using polymer membranes, the associated USB interface drive electronics, and different ways that this technology can be configured into a low-cost compact adaptive optics system. We also present results of a parametric study of the stochastic parallel gradient descent (SPGD) control algorithm.

  12. Proposed adaptive optics system for Vainu Bappu Telescope

    NASA Astrophysics Data System (ADS)

    Saxena, A. K.; Chinnappan, V.; Lancelot, J. P.

    It is known that the atmospheric turbulence spreads the star image as produced by the medium and large size optical telescopes by many orders resulting in reduction in the resolution of these telescopes. Adaptive optics system can partially or substantially sharpen the image thus improving the resolution and throughput of these telescopes. The atmospheric degradation can be effectively represented by Fried's parameter. We have measured Fried's parameter at very short intervals using speckle interferometer at VBT. Based on this input, an on-line wavefront error measurement and correction system was developed and tested in the laboratory. Low cost, high speed wavefront sensor using CMOS imager and Shack-Hartman lenslet array was developed and tested in the laboratory which could be used for on-line correction experiments. The wavefront errors are computed in terms of Zernike coefficients. MEMS based adaptive mirror with 37 actuators was used for the correction of higher order aberrations. Finite element analysis was carried out to know the mechanical properties and the influence function of the mirror. In-house developed Long Trace Profilometer was used to measure the surface produced by the mirror for various combination of actuator voltages and gave good insight about the behaviour of the mirror. An aberrated wavefront was captured by the wave-front sensor and the computed Zernike polynomials were used for correction of the wavefront. It is found that the peak intensity has increased about 3.8 times with reduction in size of the image. Now, the plan is to make a version that can be mounted at the cassegrain focus of the telescope. Here we deal with the low cost approach used in design; new algorithms developed for wavefront error computation from noisy data, speed optimization and related issues and the interface problems for using the system in the telescope.

  13. Adaptation and Diversification of an RNA Replication System under Initiation- or Termination-Impaired Translational Conditions.

    PubMed

    Mizuuchi, Ryo; Ichihashi, Norikazu; Yomo, Tetsuya

    2016-07-01

    Adaptation to various environments is a remarkable characteristic of life. Is this limited to extant complex living organisms, or is it also possible for a simpler self-replication system to adapt? In this study, we addressed this question by using a translation-coupled RNA replication system that comprised a reconstituted translation system and an RNA "genome" that encoded a replicase gene. We performed RNA replication reactions under four conditions, under which different components of translation were partly inhibited. We found that replication efficiency increased with the number of rounds of replication under all the tested conditions. The types of dominant mutations differed depending on the condition, thus indicating that this simple system adapted to different environments in different ways. This suggests that even a primitive self-replication system composed of a small number of genes on the early earth could have had the ability to adapt to various environments. PMID:27038303

  14. Systems Engineering, Quality and Testing

    NASA Technical Reports Server (NTRS)

    Shepherd, Christena C.

    2015-01-01

    AS9100 has little to say about how to apply a Quality Management System (QMS) to aerospace test programs. There is little in the quality engineering Body of Knowledge that applies to testing, unless it is nondestructive examination or some type of lab or bench testing. If one examines how the systems engineering processes are implemented throughout a test program; and how these processes can be mapped to AS9100, a number of areas for involvement of the quality professional are revealed.

  15. Portable Health Algorithms Test System

    NASA Technical Reports Server (NTRS)

    Melcher, Kevin J.; Wong, Edmond; Fulton, Christopher E.; Sowers, Thomas S.; Maul, William A.

    2010-01-01

    A document discusses the Portable Health Algorithms Test (PHALT) System, which has been designed as a means for evolving the maturity and credibility of algorithms developed to assess the health of aerospace systems. Comprising an integrated hardware-software environment, the PHALT system allows systems health management algorithms to be developed in a graphical programming environment, to be tested and refined using system simulation or test data playback, and to be evaluated in a real-time hardware-in-the-loop mode with a live test article. The integrated hardware and software development environment provides a seamless transition from algorithm development to real-time implementation. The portability of the hardware makes it quick and easy to transport between test facilities. This hard ware/software architecture is flexible enough to support a variety of diagnostic applications and test hardware, and the GUI-based rapid prototyping capability is sufficient to support development execution, and testing of custom diagnostic algorithms. The PHALT operating system supports execution of diagnostic algorithms under real-time constraints. PHALT can perform real-time capture and playback of test rig data with the ability to augment/ modify the data stream (e.g. inject simulated faults). It performs algorithm testing using a variety of data input sources, including real-time data acquisition, test data playback, and system simulations, and also provides system feedback to evaluate closed-loop diagnostic response and mitigation control.

  16. The AdaptiV Approach to Verification of Adaptive Systems

    SciTech Connect

    Rouff, Christopher; Buskens, Richard; Pullum, Laura L; Cui, Xiaohui; Hinchey, Mike

    2012-01-01

    Adaptive systems are critical for future space and other unmanned and intelligent systems. Verification of these systems is also critical for their use in systems with potential harm to human life or with large financial investments. Due to their nondeterministic nature and extremely large state space, current methods for verification of software systems are not adequate to provide a high level of assurance. The combination of stabilization science, high performance computing simulations, compositional verification and traditional verification techniques, plus operational monitors, provides a complete approach to verification and deployment of adaptive systems that has not been used before. This paper gives an overview of this approach.

  17. An integrated architecture of adaptive neural network control for dynamic systems

    SciTech Connect

    Ke, Liu; Tokar, R.; Mcvey, B.

    1994-07-01

    In this study, an integrated neural network control architecture for nonlinear dynamic systems is presented. Most of the recent emphasis in the neural network control field has no error feedback as the control input which rises the adaptation problem. The integrated architecture in this paper combines feed forward control and error feedback adaptive control using neural networks. The paper reveals the different internal functionality of these two kinds of neural network controllers for certain input styles, e.g., state feedback and error feedback. Feed forward neural network controllers with state feedback establish fixed control mappings which can not adapt when model uncertainties present. With error feedbacks, neural network controllers learn the slopes or the gains respecting to the error feedbacks, which are error driven adaptive control systems. The results demonstrate that the two kinds of control scheme can be combined to realize their individual advantages. Testing with disturbances added to the plant shows good tracking and adaptation.

  18. RASCAL: A Rudimentary Adaptive System for Computer-Aided Learning.

    ERIC Educational Resources Information Center

    Stewart, John Christopher

    Both the background of computer-assisted instruction (CAI) systems in general and the requirements of a computer-aided learning system which would be a reasonable assistant to a teacher are discussed. RASCAL (Rudimentary Adaptive System for Computer-Aided Learning) is a first attempt at defining a CAI system which would individualize the learning…

  19. Architecture and performance of astronomical adaptive optics systems

    NASA Technical Reports Server (NTRS)

    Bloemhof, E.

    2002-01-01

    In recent years the technological advances of adaptive optics have enabled a great deal of innovative science. In this lecture I review the system-level design of modern astronomical AO instruments, and discuss their current capabilities.

  20. On the rejection of vibrations in adaptive optics systems

    NASA Astrophysics Data System (ADS)

    Muradore, Riccardo; Pettazzi, Lorenzo; Fedrigo, Enrico; Clare, Richard

    2012-07-01

    In modern adaptive optics systems, lightly damped sinusoidal oscillations resulting from telescope structural vibrations have a significant deleterious impact on the quality of the image collected at the detector plane. Such oscillations are often at frequencies beyond the bandwidth of the wave-front controller that therefore is either incapable of rejecting them or might even amplify their detrimental impact on the overall AO performance. A technique for the rejection of periodic disturbances acting at the output of unknown plants, which has been recently presented in literature, has been adapted to the problem of rejecting vibrations in AO loops. The proposed methodology aims at estimating phase and amplitude of the harmonic disturbance together with the response of the unknown plant at the frequency of vibration. On the basis of such estimates, a control signal is generated to cancel out the periodic perturbation. Additionally, the algorithm can be easily extended to cope with unexpected time variations of the vibrations frequency by adding a frequency tracking module based either on a simple PLL architecture or on a classical extended Kalman filter. Oversampling can be also easily introduced to efficiently correct for vibrations approaching the sampling frequency. The approach presented in this contribution is compared against a different algorithm for vibration rejection available in literature, in order to identify drawbacks and advantages. Finally, the performance of the proposed vibration cancellation technique has been tested in realistic scenarios defined exploiting tip/tilt measurements from MACAO and NACO

  1. Global adaptive control for uncertain nonaffine nonlinear hysteretic systems.

    PubMed

    Liu, Yong-Hua; Huang, Liangpei; Xiao, Dongming; Guo, Yong

    2015-09-01

    In this paper, the global output tracking is investigated for a class of uncertain nonlinear hysteretic systems with nonaffine structures. By combining the solution properties of the hysteresis model with the novel backstepping approach, a robust adaptive control algorithm is developed without constructing a hysteresis inverse. The proposed control scheme is further modified to tackle the bounded disturbances by adaptively estimating their bounds. It is rigorously proven that the designed adaptive controllers can guarantee global stability of the closed-loop system. Two numerical examples are provided to show the effectiveness of the proposed control schemes. PMID:26169122

  2. Adaptive Mesh Refinement and Adaptive Time Integration for Electrical Wave Propagation on the Purkinje System

    PubMed Central

    Ying, Wenjun; Henriquez, Craig S.

    2015-01-01

    A both space and time adaptive algorithm is presented for simulating electrical wave propagation in the Purkinje system of the heart. The equations governing the distribution of electric potential over the system are solved in time with the method of lines. At each timestep, by an operator splitting technique, the space-dependent but linear diffusion part and the nonlinear but space-independent reactions part in the partial differential equations are integrated separately with implicit schemes, which have better stability and allow larger timesteps than explicit ones. The linear diffusion equation on each edge of the system is spatially discretized with the continuous piecewise linear finite element method. The adaptive algorithm can automatically recognize when and where the electrical wave starts to leave or enter the computational domain due to external current/voltage stimulation, self-excitation, or local change of membrane properties. Numerical examples demonstrating efficiency and accuracy of the adaptive algorithm are presented. PMID:26581455

  3. A model for culturally adapting a learning system.

    PubMed

    Del Rosario, M L

    1975-12-01

    The Cross-Cultural Adaption Model (XCAM) is designed to help identify cultural values contained in the text, narration, or visual components of a learning instrument and enables the adapter to evaluate his adapted model so that he can modify or revise it, and allows him to assess the modified version by actually measuring the amount of cultural conflict still present in it. Such a model would permit world-wide adaption of learning materials in population regulation. A random sample of the target group is selected. The adapter develops a measurin g instrument, the cross-cultural adaption scale (XCA), a number of statements about the cultural affinity of the object evaluated. The pretest portion of the sample tests the clarity and understandability of the rating scale to be used for evaluating the instructional materials; the pilot group analyzes the original version of the instructional mater ials, determines the criteria for change, and analyzes the adapted version in terms of these criteria; the control group is administered the original version of the learning materials; and the experimental group is administered the adapted version. Finally, the responses obtained from the XRA rating scale and discussions of both the experimental and control groups are studied and group differences are ev aluated according to cultural conflicts met with each version. With this data, the preferred combination of elements is constructed. PMID:12307758

  4. Assessment of Postflight Locomotor Performance Utilizing a Test of Functional Mobility: Strategic and Adaptive Responses

    NASA Technical Reports Server (NTRS)

    Warren, L. E.; Mulavara, A. P.; Peters, B. T.; Cohen, H. S.; Richards, J. T.; Miller, C. A.; Brady, R.; Ruttley, T. M.; Bloomberg, J. J.

    2006-01-01

    have further analyzed the FMT data to characterize strategic and adaptive components during the postflight readaptation period. Crewmembers walked at a preferred pace through an obstacle course set up on a base of 10 cm thick medium density foam (Sunmate Foam, Dynamic Systems, Inc., Leicester, NC). The 6.0m X 4.0m course consisted of several pylons made of foam; a Styrofoam barrier 46.0cm high that crewmembers stepped over; and a portal constructed of two Styrofoam blocks, each 31cm high, with a horizontal bar covered by foam and suspended from the ceiling which was adjusted to the height of the crewmember s shoulder. The portal required crewmembers to bend at the waist and step over a barrier simultaneously. All obstacles were lightweight, soft and easily knocked over. Crewmembers were instructed to walk through the course as quickly and as safely as possible without touching any of the objects on the course. This task was performed three times in the clockwise direction and three times in the counterclockwise direction that was randomly chosen. The dependent measures for each trial were: time to complete the course (seconds) and the number of obstacles touched or knocked down. For each crewmember, the time to complete each FMT trial from postflight days 1, 2, 4, 7 and 25 were further analyzed. A single logarithmic curve using a least squares calculation was fit through these data to produce a single comprehensive curve (macro). This macro curve composed of data spanning 25 days, illustrates the re-adaptive learning function over the longer time scale term. Additionally, logarithmic curves were fit to the 6 data trials within each individual post flight test day to produce 5 separate daily curves. These micro curves, produced from data obtained over the course of minutes, illustrates the strategic learning function exhibited over a relative shorter time scale. The macro curve for all subjects exhibited adaptive motor learning patterns over the 25 day period. Howev, 9

  5. Design of an adaptive neural network based power system stabilizer.

    PubMed

    Liu, Wenxin; Venayagamoorthy, Ganesh K; Wunsch, Donald C

    2003-01-01

    Power system stabilizers (PSS) are used to generate supplementary control signals for the excitation system in order to damp the low frequency power system oscillations. To overcome the drawbacks of conventional PSS (CPSS), numerous techniques have been proposed in the literature. Based on the analysis of existing techniques, this paper presents an indirect adaptive neural network based power system stabilizer (IDNC) design. The proposed IDNC consists of a neuro-controller, which is used to generate a supplementary control signal to the excitation system, and a neuro-identifier, which is used to model the dynamics of the power system and to adapt the neuro-controller parameters. The proposed method has the features of a simple structure, adaptivity and fast response. The proposed IDNC is evaluated on a single machine infinite bus power system under different operating conditions and disturbances to demonstrate its effectiveness and robustness. PMID:12850048

  6. The Danger of Relying Solely on Diagnostic Adaptive Testing When Prior and Subsequent Instructional Methods Are Different. Research Report No. 2, October 1 through December 31, 1979.

    ERIC Educational Resources Information Center

    Tatsuoka, Kikumi; Birenbaum, Menucha

    A situation in which computer-assisted instruction was combined with teacher-taught classes and computerized diagnostic adaptive testing was examined. The computerized diagnostic adaptive test for pre-algebra signed-number lessons was programmed along with a computer-managed routing system by which examinees were sent to the instructional unit…

  7. Optimizing Input/Output Using Adaptive File System Policies

    NASA Technical Reports Server (NTRS)

    Madhyastha, Tara M.; Elford, Christopher L.; Reed, Daniel A.

    1996-01-01

    Parallel input/output characterization studies and experiments with flexible resource management algorithms indicate that adaptivity is crucial to file system performance. In this paper we propose an automatic technique for selecting and refining file system policies based on application access patterns and execution environment. An automatic classification framework allows the file system to select appropriate caching and pre-fetching policies, while performance sensors provide feedback used to tune policy parameters for specific system environments. To illustrate the potential performance improvements possible using adaptive file system policies, we present results from experiments involving classification-based and performance-based steering.

  8. PHURBAS: AN ADAPTIVE, LAGRANGIAN, MESHLESS, MAGNETOHYDRODYNAMICS CODE. II. IMPLEMENTATION AND TESTS

    SciTech Connect

    McNally, Colin P.; Mac Low, Mordecai-Mark; Maron, Jason L. E-mail: jmaron@amnh.org

    2012-05-01

    We present an algorithm for simulating the equations of ideal magnetohydrodynamics and other systems of differential equations on an unstructured set of points represented by sample particles. The particles move with the fluid, so the time step is not limited by the Eulerian Courant-Friedrichs-Lewy condition. Full spatial adaptivity is required to ensure the particles fill the computational volume and gives the algorithm substantial flexibility and power. A target resolution is specified for each point in space, with particles being added and deleted as needed to meet this target. We have parallelized the code by adapting the framework provided by GADGET-2. A set of standard test problems, including 10{sup -6} amplitude linear magnetohydrodynamics waves, magnetized shock tubes, and Kelvin-Helmholtz instabilities is presented. Finally, we demonstrate good agreement with analytic predictions of linear growth rates for magnetorotational instability in a cylindrical geometry. This paper documents the Phurbas algorithm as implemented in Phurbas version 1.1.

  9. Development and Evaluation of a Confidence-Weighting Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Yen, Yung-Chin; Ho, Rong-Guey; Chen, Li-Ju; Chou, Kun-Yi; Chen, Yan-Lin

    2010-01-01

    The purpose of this study was to examine whether the efficiency, precision, and validity of computerized adaptive testing (CAT) could be improved by assessing confidence differences in knowledge that examinees possessed. We proposed a novel polytomous CAT model called the confidence-weighting computerized adaptive testing (CWCAT), which combined a…

  10. Ultrasonic test system

    NASA Astrophysics Data System (ADS)

    Smith, Anthony; Goff, Dan; Kruchowy, Roman; Rhoads, Carl

    1994-08-01

    An ultrasonic system for determining the quality of concrete under water without inaccuracies caused by electromagnetic interference from the ultrasonic generator. An ultrasonic generator applies pulses to the concrete. An ultrasonic detector detects the ultrasonic pulses and produces corresponding signals that are indicative of ultrasonic pulses that have passed through the material. Signal processing circuitry processes the signals to determine the transit time of the ultrasonic pulses through the material. The signal processing circuitry is disabled for a predetermined time after application of each ultrasonic pulse to the material to prevent noise produced by the means for applying ultrasonic pulses to the material from entering the signal processing circuitry and causing spurious measurements.

  11. Flight test results of the fuzzy logic adaptive controller-helicopter (FLAC-H)

    NASA Astrophysics Data System (ADS)

    Wade, Robert L.; Walker, Gregory W.

    1996-05-01

    The fuzzy logic adaptive controller for helicopters (FLAC-H) demonstration is a cooperative effort between the US Army Simulation, Training, and Instrumentation Command (STRICOM), the US Army Aviation and Troop Command, and the US Army Missile Command to demonstrate a low-cost drone control system for both full-scale and sub-scale helicopters. FLAC-H was demonstrated on one of STRICOM's fleet of full-scale rotary-winged target drones. FLAC-H exploits fuzzy logic in its flight control system to provide a robust solution to the control of the helicopter's dynamic, nonlinear system. Straight forward, common sense fuzzy rules governing helicopter flight are processed instead of complex mathematical models. This has resulted in a simplified solution to the complexities of helicopter flight. Incorporation of fuzzy logic reduced the cost of development and should also reduce the cost of maintenance of the system. An adaptive algorithm allows the FLAC-H to 'learn' how to fly the helicopter, enabling the control system to adjust to varying helicopter configurations. The adaptive algorithm, based on genetic algorithms, alters the fuzzy rules and their related sets to improve the performance characteristics of the system. This learning allows FLAC-H to automatically be integrated into a new airframe, reducing the development costs associated with altering a control system for a new or heavily modified aircraft. Successful flight tests of the FLAC-H on a UH-1H target drone were completed in September 1994 at the White Sands Missile Range in New Mexico. This paper discuses the objective of the system, its design, and performance.

  12. An adaptive tracking observer for failure-detection systems

    NASA Technical Reports Server (NTRS)

    Sidar, M.

    1982-01-01

    The design problem of adaptive observers applied to linear, constant and variable parameters, multi-input, multi-output systems, is considered. It is shown that, in order to keep the observer's (or Kalman filter) false-alarm rate (FAR) under a certain specified value, it is necessary to have an acceptable proper matching between the observer (or KF) model and the system parameters. An adaptive observer algorithm is introduced in order to maintain desired system-observer model matching, despite initial mismatching and/or system parameter variations. Only a properly designed adaptive observer is able to detect abrupt changes in the system (actuator, sensor failures, etc.) with adequate reliability and FAR. Conditions for convergence for the adaptive process were obtained, leading to a simple adaptive law (algorithm) with the possibility of an a priori choice of fixed adaptive gains. Simulation results show good tracking performance with small observer output errors and accurate and fast parameter identification, in both deterministic and stochastic cases.

  13. Holographic system for nondestructive testing

    NASA Technical Reports Server (NTRS)

    Kurtz, R. L. (Inventor)

    1975-01-01

    A description is given of a holographic system for nondestructive testing. The system is comprised of a mirror which illuminates the test object surface; the mirror is positionable to direct illumination on an object at varying angles with respect to a line normal to the surface of the object. In this manner holograms may be produced with varying degrees of sensitivity enabling optimum observation of dimensions of deformation of an object occurring between test exposures.

  14. Adaptable Information Models in the Global Change Information System

    NASA Astrophysics Data System (ADS)

    Duggan, B.; Buddenberg, A.; Aulenbach, S.; Wolfe, R.; Goldstein, J.

    2014-12-01

    The US Global Change Research Program has sponsored the creation of the Global Change Information System () to provide a web based source of accessible, usable, and timely information about climate and global change for use by scientists, decision makers, and the public. The GCIS played multiple roles during the assembly and release of the Third National Climate Assessment. It provided human and programmable interfaces, relational and semantic representations of information, and discrete identifiers for various types of resources, which could then be manipulated by a distributed team with a wide range of specialties. The GCIS also served as a scalable backend for the web based version of the report. In this talk, we discuss the infrastructure decisions made during the design and deployment of the GCIS, as well as ongoing work to adapt to new types of information. Both a constrained relational database and an open ended triple store are used to ensure data integrity while maintaining fluidity. Using natural primary keys allows identifiers to propagate through both models. Changing identifiers are accomodated through fine grained auditing and explicit mappings to external lexicons. A practical RESTful API is used whose endpoints are also URIs in an ontology. Both the relational schema and the ontology are maleable, and stability is ensured through test driven development and continuous integration testing using modern open source techniques. Content is also validated through continuous testing techniques. A high degres of scalability is achieved through caching.

  15. Integration and bench testing for the GRAVITY Coudé IR adaptive optics (CIAO) wavefront sensor

    NASA Astrophysics Data System (ADS)

    Deen, C.; Yang, P.; Huber, A.; Suarez-Valles, M.; Hippler, S.; Brandner, W.; Gendron, E.; Clénet, Y.; Kendrew, S.; Glauser, A.; Klein, R.; Laun, W.; Lenzen, R.; Neumann, U.; Panduro, J.; Ramos, J.; Rohloff, R.-R.; Salzinger, A.; Zimmerman, N.; Henning, T.; Perraut, K.; Perrin, G.; Straubmeier, C.; Amorim, A.; Eisenhauer, F.

    2014-08-01

    GRAVITY, a second generation instrument for the Very Large Telescope Interferometer (VLTI), will provide an astrometric precision of order 10 micro-arcseconds, an imaging resolution of 4 milli-arcseconds, and low/medium resolution spectro-interferometry. These improvements to the VLTI represent a major upgrade to its current infrared interferometric capabilities, allowing detailed study of obscured environments (e.g. the Galactic Center, young dusty planet-forming disks, dense stellar cores, AGN, etc...). Crucial to the final performance of GRAVITY, the Coudé IR Adaptive Optics (CIAO) system will correct for the effects of the atmosphere at each of the VLT Unit Telescopes. CIAO consists of four new infrared Shack-Hartmann wavefront sensors (WFS) and associated real-time computers/software which will provide infrared wavefront sensing from 1.45-2.45 microns, allowing AO corrections even in regions where optically bright reference sources are scarce. We present here the latest progress on the GRAVITY wavefront sensors. We describe the adaptation and testing of a light-weight version of the ESO Standard Platform for Adaptive optics Real Time Applications (SPARTA-Light) software architecture to the needs of GRAVITY. We also describe the latest integration and test milestones for construction of the initial wave front sensor.

  16. Automated flight test management system

    NASA Technical Reports Server (NTRS)

    Hewett, M. D.; Tartt, D. M.; Agarwal, A.

    1991-01-01

    The Phase 1 development of an automated flight test management system (ATMS) as a component of a rapid prototyping flight research facility for artificial intelligence (AI) based flight concepts is discussed. The ATMS provides a flight engineer with a set of tools that assist in flight test planning, monitoring, and simulation. The system is also capable of controlling an aircraft during flight test by performing closed loop guidance functions, range management, and maneuver-quality monitoring. The ATMS is being used as a prototypical system to develop a flight research facility for AI based flight systems concepts at NASA Ames Dryden.

  17. Adaptive Neural Network Based Control of Noncanonical Nonlinear Systems.

    PubMed

    Zhang, Yanjun; Tao, Gang; Chen, Mou

    2016-09-01

    This paper presents a new study on the adaptive neural network-based control of a class of noncanonical nonlinear systems with large parametric uncertainties. Unlike commonly studied canonical form nonlinear systems whose neural network approximation system models have explicit relative degree structures, which can directly be used to derive parameterized controllers for adaptation, noncanonical form nonlinear systems usually do not have explicit relative degrees, and thus their approximation system models are also in noncanonical forms. It is well-known that the adaptive control of noncanonical form nonlinear systems involves the parameterization of system dynamics. As demonstrated in this paper, it is also the case for noncanonical neural network approximation system models. Effective control of such systems is an open research problem, especially in the presence of uncertain parameters. This paper shows that it is necessary to reparameterize such neural network system models for adaptive control design, and that such reparameterization can be realized using a relative degree formulation, a concept yet to be studied for general neural network system models. This paper then derives the parameterized controllers that guarantee closed-loop stability and asymptotic output tracking for noncanonical form neural network system models. An illustrative example is presented with the simulation results to demonstrate the control design procedure, and to verify the effectiveness of such a new design method. PMID:26285223

  18. Research on Algorithms based on Web Self-adaptive Study and Intelligent Test Paper Construction and their Applications

    NASA Astrophysics Data System (ADS)

    Liu, Ying; Wang, Limin; Huang, Lihua; Han, Xuming; Gu, Zhenshan; Sang, Juan

    A novel system based on Bernoulli Theorem of Large Number Law and the genetic algorithms was designed and realized in this paper, which had many advantages such as self-adaptive study for difficulty coefficient of item pool and intelligent test paper construction etc. At present, the system has applied in the examination of paperless computer tests of Jinlin university of finance and economics and some satisfactory results have been also obtained.

  19. Comparison and Equating of Paper-Administered, Computer-Administered and Computerized Adaptive Tests of Achievement.

    ERIC Educational Resources Information Center

    Olsen, James B.; And Others

    Student achievement test scores were compared and equated, using three different testing methods: paper-administered, computer-administered, and computerized adaptive testing. The tests were developed from third and sixth grade mathematics item banks of the California Assessment Program. The paper and the computer-administered tests were identical…

  20. Item Pocket Method to Allow Response Review and Change in Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Han, Kyung T.

    2013-01-01

    Most computerized adaptive testing (CAT) programs do not allow test takers to review and change their responses because it could seriously deteriorate the efficiency of measurement and make tests vulnerable to manipulative test-taking strategies. Several modified testing methods have been developed that provide restricted review options while…

  1. Applications of Adaptive Testing in Measuring Achievement and Performance.

    ERIC Educational Resources Information Center

    Bejar, Issac I.

    The concept of testing for partial knowledge is considered with the concept of tailored testing. Following the special usage of latent trait theory, the word valdity is used to mean the correlation of a test with the construct the test measures. The concept of a method factor in the test is also considered as a part of the validity. The possible…

  2. Testing Orions Fairing Separation System

    NASA Technical Reports Server (NTRS)

    Martinez, Henry; Cloutier, Chris; Lemmon, Heber; Rakes, Daniel; Oldham, Joe; Schlagel, Keith

    2014-01-01

    Traditional fairing systems are designed to fully encapsulate and protect their payload from the harsh ascent environment including acoustic vibrations, aerodynamic forces and heating. The Orion fairing separation system performs this function and more by also sharing approximately half of the vehicle structural load during ascent. This load-share condition through launch and during jettison allows for a substantial increase in mass to orbit. A series of component-level development tests were completed to evaluate and characterize each component within Orion's unique fairing separation system. Two full-scale separation tests were performed to verify system-level functionality and provide verification data. This paper summarizes the fairing spring, Pyramidal Separation Mechanism and forward seal system component-level development tests, system-level separation tests, and lessons learned.

  3. Testing the equality of students' performance using Alexander-Govern test with adaptive trimmed means

    NASA Astrophysics Data System (ADS)

    Abdullah, Suhaida; Yahaya, Sharipah Soaad Syed; Yusof, Zahayu Md

    2014-06-01

    Analyzing the equality of independent group has to be done with caution. The classical approaches such as ttest for two groups and analysis of variance (ANOVA) for more than two groups always are favorable selection by researchers. However, sometime these methods were abused by the presence of nonnormality or variance heterogeneity or both. It is known that ANOVA is restricted to the assumptions of normality and homogeneity of variance. In real life data, sometimes these requirements are hard to attain. The Alexander-Govern test with adaptive trimmed mean (AG_atm) is one approach that can be chosen as alternative to the classical tests when their assumptions are violated. In this paper, the performances of AG_atm were compared to the original AG test and ANOVA using simulated and real life data. The simulation study proved that the AG_atm performs better than the original AG test and the classical test. For real life data, student's performance in decision analysis course, measured by final examination score was chosen. Based on the exploratory data analysis, this data found to have problem of nonnormality.

  4. A formal protocol test procedure for the Survivable Adaptable Fiber Optic Embedded Network (SAFENET)

    NASA Astrophysics Data System (ADS)

    High, Wayne

    1993-03-01

    This thesis focuses upon a new method for verifying the correct operation of a complex, high speed fiber optic communication network. These networks are of growing importance to the military because of their increased connectivity, survivability, and reconfigurability. With the introduction and increased dependence on sophisticated software and protocols, it is essential that their operation be correct. Because of the speed and complexity of fiber optic networks being designed today, they are becoming increasingly difficult to test. Previously, testing was accomplished by application of conformance test methods which had little connection with an implementation's specification. The major goal of conformance testing is to ensure that the implementation of a profile is consistent with its specification. Formal specification is needed to ensure that the implementation performs its intended operations while exhibiting desirable behaviors. The new conformance test method presented is based upon the System of Communicating Machine model which uses a formal protocol specification to generate a test sequence. The major contribution of this thesis is the application of the System of Communicating Machine model to formal profile specifications of the Survivable Adaptable Fiber Optic Embedded Network (SAFENET) standard which results in the derivation of test sequences for a SAFENET profile. The results applying this new method to SAFENET's OSI and Lightweight profiles are presented.

  5. Variable neural adaptive robust control: a switched system approach.

    PubMed

    Lian, Jianming; Hu, Jianghai; Żak, Stanislaw H

    2015-05-01

    Variable neural adaptive robust control strategies are proposed for the output tracking control of a class of multiinput multioutput uncertain systems. The controllers incorporate a novel variable-structure radial basis function (RBF) network as the self-organizing approximator for unknown system dynamics. It can determine the network structure online dynamically by adding or removing RBFs according to the tracking performance. The structure variation is systematically considered in the stability analysis of the closed-loop system using a switched system approach with the piecewise quadratic Lyapunov function. The performance of the proposed variable neural adaptive robust controllers is illustrated with simulations. PMID:25881366

  6. The reduced order model problem in distributed parameter systems adaptive identification and control. [adaptive control of flexible spacecraft

    NASA Technical Reports Server (NTRS)

    Johnson, C. R., Jr.; Lawrence, D. A.

    1981-01-01

    The reduced order model problem in distributed parameter systems adaptive identification and control is investigated. A comprehensive examination of real-time centralized adaptive control options for flexible spacecraft is provided.

  7. Automatic tools for system testing

    NASA Technical Reports Server (NTRS)

    Peccia, N. M.

    1993-01-01

    As spacecraft control and other space-related ground systems become increasingly complex, the effort required in testing and validation also increases. Implementation of a spacecraft control system normally involves a number of incremental deliveries. In addition kernel or general purpose software may also be involved, which must itself be considered in the integration and testing program. Tools can be used to assist this testing. These can reduce the effort required or alternatively they can ensure that for a given level of effort, a better job is done. Great benefit could be derived by automating certain types of testing (interactive software) which up to now has been performed manually at a terminal. This paper reports on an on-going study. The study examines means of automating spacecraft control system testing, evaluates relevant commercial tools and aims to prototype basic automatic testing functions.

  8. Adaptive controller for a needle free jet-injector system.

    PubMed

    Modak, Ashin; Hogan, N Catherine; Hunter, Ian W

    2015-08-01

    A nonlinear, sliding mode adaptive controller was created for a needle-free jet injection system. The controller was based on a simplified lumped-sum parameter model of the jet-injection mechanics. The adaptive control scheme was compared to a currently-used Feed-forward+PID controller in both ejection of water into air, and injection of dye into ex-vivo porcine tissue. The adaptive controller was more successful in trajectory tracking and was more robust to the biological variations caused by a tissue load. PMID:26737988

  9. Alignment and integration of ASSIST: a test bench for VLT adaptive optics facility

    NASA Astrophysics Data System (ADS)

    Deep, Atul; Arsenault, Robin; Boland, Wilfried; Delabre, Bernard; Hubin, Norbert; La Penna, Paolo; Madec, Pierre-Yves; Molster, Frank; Stuik, Remko; Tordo, Sebastien; Wiegers, Emiel

    2010-08-01

    ASSIST, The Adaptive Secondary Setup and Instrument STimulator, is being developed to provide a testing facility for the ESO Adaptive Optics Facility (AOF). It will allow the off-telescope testing of three elements of the VLT AOF; the Deformable Secondary Mirror (DSM) and the AO systems for MUSE and HAWK-I (GALACSI and GRAAL). The core of ASSIST consists of a 2-mirror setup (AM1-AM2) allowing the on-axis test of the DSM in interferometric mode. However, during the initial stages of ASSIST integration, DSM would not be present. This makes the task of aligning AM1-AM2 to within an accuracy of 0.05mm/1 arcmin rather challenging. A novel technique known as Shack-Hartmann method has been developed and tested in the lab for this purpose. A Shack Hartmann wavefront sensor will be used to measure the mis-alignment between AM1-AM2 by recording the coma and astigmatism in the presence of large spherical aberration introduced because of tilt/decenter of AM2 with respect to AM1. Thereafter, 20 optical components including lenses, flat mirrors and beam-splitter cubes divided into five sub-assemblies should be aligned to AM1-AM2- DSM axis which ultimately passes through the mechanical axis of large AMOS rotator.

  10. Adaptive stochastic control for a class of linear systems.

    NASA Technical Reports Server (NTRS)

    Tse, E.; Athans, M.

    1972-01-01

    The problem considered in this paper deals with the control of linear discrete-time stochastic systems with unknown (possibly time-varying and random) gain parameters. The philosophy of control is based on the use of an open-loop feedback optimal (OLFO) control using a quadratic index of performance. It is shown that the OLFO system consists of (1) an identifier that estimates the system state variables and gain parameters and (2) a controller described by an 'adaptive' gain and correction term. Several qualitative properties and asymptotic properties of the OLFO adaptive system are discussed. Simulation results dealing with the control of stable and unstable third-order plants are presented. The key quantitative result is the precise variation of the control system adaptive gains as a function of the future expected uncertainty of the parameters; thus, in this problem the ordinary 'separation theorem' does not hold.

  11. Adaptive Fuzzy Systems in Computational Intelligence

    NASA Technical Reports Server (NTRS)

    Berenji, Hamid R.

    1996-01-01

    In recent years, the interest in computational intelligence techniques, which currently includes neural networks, fuzzy systems, and evolutionary programming, has grown significantly and a number of their applications have been developed in the government and industry. In future, an essential element in these systems will be fuzzy systems that can learn from experience by using neural network in refining their performances. The GARIC architecture, introduced earlier, is an example of a fuzzy reinforcement learning system which has been applied in several control domains such as cart-pole balancing, simulation of to Space Shuttle orbital operations, and tether control. A number of examples from GARIC's applications in these domains will be demonstrated.

  12. Communication system with adaptive noise suppression

    NASA Technical Reports Server (NTRS)

    Kozel, David (Inventor); Devault, James A. (Inventor); Birr, Richard B. (Inventor)

    2007-01-01

    A signal-to-noise ratio dependent adaptive spectral subtraction process eliminates noise from noise-corrupted speech signals. The process first pre-emphasizes the frequency components of the input sound signal which contain the consonant information in human speech. Next, a signal-to-noise ratio is determined and a spectral subtraction proportion adjusted appropriately. After spectral subtraction, low amplitude signals can be squelched. A single microphone is used to obtain both the noise-corrupted speech and the average noise estimate. This is done by determining if the frame of data being sampled is a voiced or unvoiced frame. During unvoiced frames an estimate of the noise is obtained. A running average of the noise is used to approximate the expected value of the noise. Spectral subtraction may be performed on a composite noise-corrupted signal, or upon individual sub-bands of the noise-corrupted signal. Pre-averaging of the input signal's magnitude spectrum over multiple time frames may be performed to reduce musical noise.

  13. Adaptive control of Hammerstein-Wiener nonlinear systems

    NASA Astrophysics Data System (ADS)

    Zhang, Bi; Hong, Hyokchan; Mao, Zhizhong

    2016-07-01

    The Hammerstein-Wiener model is a block-oriented model, having a linear dynamic block sandwiched by two static nonlinear blocks. This note develops an adaptive controller for a special form of Hammerstein-Wiener nonlinear systems which are parameterized by the key-term separation principle. The adaptive control law and recursive parameter estimation are updated by the use of internal variable estimations. By modeling the errors due to the estimation of internal variables, we establish convergence and stability properties. Theoretical results show that parameter estimation convergence and closed-loop system stability can be guaranteed under sufficient condition. From a qualitative analysis of the sufficient condition, we introduce an adaptive weighted factor to improve the performance of the adaptive controller. Numerical examples are given to confirm the results in this paper.

  14. CMIF ECLS system test findings

    NASA Technical Reports Server (NTRS)

    Schunk, Richard G.; Carrasquillo, Robyn L.; Ogle, Kathyrn Y.; Wieland, Paul O.; Bagdigian, Robert M.

    1989-01-01

    During 1987 three Space Station integrated Environmental Control and Life Support System (ECLSS) tests were conducted at the Marshall Space Flight Center (MSFC) Core Module Integration Facility (CMIF) as part of the MSFC ECLSS Phase II test program. The three tests ranged in duration from 50 to 150 hours and were conducted inside of the CMIF module simulator. The Phase II partial integrated system test configuration consisted of four regenerative air revitalization subsystems and one regenerative water reclamation subsystem. This paper contains a discussion of results and lessons learned from the Phase II test program. The design of the Phase II test configuration and improvements made throughout the program are detailed. Future plans for the MSFC CMIF test program are provided, including an overview of planned improvements for the Phase III program.

  15. Distributed adaptive simulation through standards-based integration of simulators and adaptive learning systems.

    PubMed

    Bergeron, Bryan; Cline, Andrew; Shipley, Jaime

    2012-01-01

    We have developed a distributed, standards-based architecture that enables simulation and simulator designers to leverage adaptive learning systems. Our approach, which incorporates an electronic competency record, open source LMS, and open source microcontroller hardware, is a low-cost, pragmatic option to integrating simulators with traditional courseware. PMID:22356955

  16. Probing other solar systems with current and future adaptive optics

    SciTech Connect

    Macintosh, B; Marois, C; Phillion, D; Poyneer, L; Graham, J; Zuckerman, B; Gavel, D; Veran, J; Wilhelmsen-Evans, J; Mellis, C

    2008-09-08

    Over the past decade, the study of extrasolar planets through indirect techniques--primarily Doppler measurements--has revolutionized our understanding of other solar systems. The next major step in this field will be the direct detection and characterization, via imaging and spectroscopy, of the planets themselves. To achieve this, we must separate the light from the faint planet from the extensive glare of its parent star. We pursued this goal using the current generation of adaptive optics (AO) systems on large ground-based telescopes, using infrared imaging to search for the thermal emission from young planets and developing image processing techniques to distinguish planets from telescope-induced artifacts. Our new Angular Differential Imaging (ADI) technique, which uses the sidereal rotation of the Earth and telescope, is now standard for ground-based high-contrast imaging. Although no young planets were found in our surveys, we placed the strongest limits yet on giant planets in wide orbits (>30 AU) around young stars and characterized planetary companion candidates. The imaging of planetary companions on solar-system-like scales (5-30 AU) will require a new generation of advanced AO systems that are an order of magnitude more powerful than the LLNL-built Keck AO system. We worked to develop and test the key technologies needed for these systems, including a spatially-filtered wavefront sensor, efficient and accurate wavefront reconstruction algorithms, and precision AO wavefront control at the sub-nm level. LLNL has now been selected by the Gemini Observatory to lead the construction of the Gemini Planet Imager, a $24M instrument that will be the most advanced AO system in the world.

  17. The Bilingual as an Adaptive System

    ERIC Educational Resources Information Center

    Green, David W.

    2002-01-01

    Dijkstra and van Heuven lucidly summarize the important research generated by the BIA model and provide an excellent case for the BIA+ model with its critical separation of the identification system from the task/decision system. A keynote article necessarily offers a selective exposition of the authors' thinking and so my remarks are an…

  18. Adaptive sliding mode control for a class of chaotic systems

    SciTech Connect

    Farid, R.; Ibrahim, A.; Zalam, B.

    2015-03-30

    Chaos control here means to design a controller that is able to mitigating or eliminating the chaos behavior of nonlinear systems that experiencing such phenomenon. In this paper, an Adaptive Sliding Mode Controller (ASMC) is presented based on Lyapunov stability theory. The well known Chua's circuit is chosen to be our case study in this paper. The study shows the effectiveness of the proposed adaptive sliding mode controller.

  19. PNNL Tests Fish Passage System

    SciTech Connect

    Colotelo, Alison

    2015-03-13

    Scientists from PNNL are testing a fish transportation system developed by Whooshh Innovations. The Whooshh system uses a flexible tube that works a bit like a vacuum, guiding fish over hydroelectric dams or other structures. Compared to methods used today, this system could save money while granting fish quicker, safer passage through dams and hatcheries.

  20. Design of an Adaptive Power Regulation Mechanism and a Nozzle for a Hydroelectric Power Plant Turbine Test Rig

    NASA Astrophysics Data System (ADS)

    Mert, Burak; Aytac, Zeynep; Tascioglu, Yigit; Celebioglu, Kutay; Aradag, Selin; ETU Hydro Research Center Team

    2014-11-01

    This study deals with the design of a power regulation mechanism for a Hydroelectric Power Plant (HEPP) model turbine test system which is designed to test Francis type hydroturbines up to 2 MW power with varying head and flow(discharge) values. Unlike the tailor made regulation mechanisms of full-sized, functional HEPPs; the design for the test system must be easily adapted to various turbines that are to be tested. In order to achieve this adaptability, a dynamic simulation model is constructed in MATLAB/Simulink SimMechanics. This model acquires geometric data and hydraulic loading data of the regulation system from Autodesk Inventor CAD models and Computational Fluid Dynamics (CFD) analysis respectively. The dynamic model is explained and case studies of two different HEPPs are performed for validation. CFD aided design of the turbine guide vanes, which is used as input for the dynamic model, is also presented. This research is financially supported by Turkish Ministry of Development.

  1. Using Tests Designed to Measure Individual Sensorimotor Subsystem Perfomance to Predict Locomotor Adaptability

    NASA Technical Reports Server (NTRS)

    Peters, B. T.; Caldwell, E. E.; Batson, C. D.; Guined, J. R.; DeDios, Y. E.; Stepanyan, V.; Gadd, N. E.; Szecsy, D. L.; Mulavara, A. P.; Seidler, R. D.; Bloomberg, J. J.

    2014-01-01

    Astronauts experience sensorimotor disturbances during the initial exposure to microgravity and during the readapation phase following a return to a gravitational environment. These alterations may lead to disruption in the ability to perform mission critical functions during and after these gravitational transitions. Astronauts show significant inter-subject variation in adaptive capability following gravitational transitions. The way each individual's brain synthesizes the available visual, vestibular and somatosensory information is likely the basis for much of the variation. Identifying the presence of biases in each person's use of information available from these sensorimotor subsystems and relating it to their ability to adapt to a novel locomotor task will allow us to customize a training program designed to enhance sensorimotor adaptability. Eight tests are being used to measure sensorimotor subsystem performance. Three of these use measures of body sway to characterize balance during varying sensorimotor challenges. The effect of vision is assessed by repeating conditions with eyes open and eyes closed. Standing on foam, or on a support surface that pitches to maintain a constant ankle angle provide somatosensory challenges. Information from the vestibular system is isolated when vision is removed and the support surface is compromised, and it is challenged when the tasks are done while the head is in motion. The integration and dominance of visual information is assessed in three additional tests. The Rod & Frame Test measures the degree to which a subject's perception of the visual vertical is affected by the orientation of a tilted frame in the periphery. Locomotor visual dependence is determined by assessing how much an oscillating virtual visual world affects a treadmill-walking subject. In the third of the visual manipulation tests, subjects walk an obstacle course while wearing up-down reversing prisms. The two remaining tests include direct

  2. Screening systems adapt to changing conditions

    SciTech Connect

    Fiscor, S.

    2009-08-15

    Prep plants are installing larger screening systems and synthetic media is meeting those challenges. The largest manufacturer of synthetic screen media is Polydeck located in Spartanburg, South Carolina. The company's primary product lines include modular polyurethane and rubber screen panels and the frame systems to support the media. The modular approach overcomes a wear problem in one area of the deck common on Banana screens and facilitates maintenance. A rubber formation used in 1- x 2-pt screen panels called the Flexi design is softer and allows more vibration than standard urethane panels. The Maxi screen panel design combined with the PipeTop II frame makes the system highly versatile. 1 photo.

  3. Improved Testing Capability and Adaptability Through the Use of Wireless Sensors

    NASA Technical Reports Server (NTRS)

    Solano, Wanda M.

    2003-01-01

    From the first Saturn V rocket booster (S-II-T) testing in 1966 and the routine Space Shuttle Main Engine (SSME) testing beginning in 1975, to more recent test programs such as the X-33 Aerospike Engine, the Integrated Powerhead Development (IPD) program, and the Hybrid Sounding Rocket (HYSR), Stennis Space Center (SSC) continues to be a premier location for conducting large-scale testing. Central to each test program is the capability for sensor systems to deliver reliable measurements and high quality data, while also providing a means to monitor the test stand area to the highest degree of safety and sustainability. Sensor wiring is routed along piping and through cable trenches, making its way from the engine test area, through the test stand area and to the signal conditioning building before final transfer to the test control center. When sensor requirements lie outside the reach of the routine sensor cable routing, the use of wireless sensor networks becomes particularly attractive due to their versatility and ease of installation. As part of an on-going effort to enhance the testing capabilities of Stennis Space Center, the Test Technology and Development group has found numerous applications for its sensor-adaptable wireless sensor suite. While not intended for critical engine measurements or control loops, in-house hardware and software development of the sensor suite can provide improved testing capability for a range of applications including the safety monitoring of propellant storage barrels and as an experimental test-bed for embedded health monitoring paradigms.

  4. Adaptation.

    PubMed

    Broom, Donald M

    2006-01-01

    The term adaptation is used in biology in three different ways. It may refer to changes which occur at the cell and organ level, or at the individual level, or at the level of gene action and evolutionary processes. Adaptation by cells, especially nerve cells helps in: communication within the body, the distinguishing of stimuli, the avoidance of overload and the conservation of energy. The time course and complexity of these mechanisms varies. Adaptive characters of organisms, including adaptive behaviours, increase fitness so this adaptation is evolutionary. The major part of this paper concerns adaptation by individuals and its relationships to welfare. In complex animals, feed forward control is widely used. Individuals predict problems and adapt by acting before the environmental effect is substantial. Much of adaptation involves brain control and animals have a set of needs, located in the brain and acting largely via motivational mechanisms, to regulate life. Needs may be for resources but are also for actions and stimuli which are part of the mechanism which has evolved to obtain the resources. Hence pigs do not just need food but need to be able to carry out actions like rooting in earth or manipulating materials which are part of foraging behaviour. The welfare of an individual is its state as regards its attempts to cope with its environment. This state includes various adaptive mechanisms including feelings and those which cope with disease. The part of welfare which is concerned with coping with pathology is health. Disease, which implies some significant effect of pathology, always results in poor welfare. Welfare varies over a range from very good, when adaptation is effective and there are feelings of pleasure or contentment, to very poor. A key point concerning the concept of individual adaptation in relation to welfare is that welfare may be good or poor while adaptation is occurring. Some adaptation is very easy and energetically cheap and

  5. An adaptive learning control system for aircraft

    NASA Technical Reports Server (NTRS)

    Mekel, R.; Nachmias, S.

    1978-01-01

    A learning control system and its utilization as a flight control system for F-8 Digital Fly-By-Wire (DFBW) research aircraft is studied. The system has the ability to adjust a gain schedule to account for changing plant characteristics and to improve its performance and the plant's performance in the course of its own operation. Three subsystems are detailed: (1) the information acquisition subsystem which identifies the plant's parameters at a given operating condition; (2) the learning algorithm subsystem which relates the identified parameters to predetermined analytical expressions describing the behavior of the parameters over a range of operating conditions; and (3) the memory and control process subsystem which consists of the collection of updated coefficients (memory) and the derived control laws. Simulation experiments indicate that the learning control system is effective in compensating for parameter variations caused by changes in flight conditions.

  6. Synthesis of oscillating adaptive feedback systems

    NASA Technical Reports Server (NTRS)

    Smay, J. W.

    1973-01-01

    A synthesis theory is developed which allows system design to proceed from practical specifications on system command and/or disturbance response to a design which is very nearly optimal in terms of feedback sensor noise effects. The approach taken is to replace the nonlinear element by a mean square error minimizing approximation (dual-input describing function), and then use linear frequency domain synthesis techniques subject to additional constraints imposed by the limit cycle and the approximator. Synthesis techniques are also developed for a similar system using an externally excited oscillating signal with the above approach. The results remove the design of the systems considered from the realm of simulation and experimentation, permitting true synthesis and the optimization that accompanies it.

  7. Thermal Performance Testing Of Cryogenic Piping Systems

    NASA Technical Reports Server (NTRS)

    Fesmire, J. E.; Augustynowicz, S. D.; Nagy, Z. F.

    2003-01-01

    Thermal performance measurement of piping systems under actual field conditions is important for space launch development and commercial industry. Knowledge of the true insulating effectiveness is needed in system design, development, and research activities. A new 18-meter-long test apparatus for cryogenic pipelines has been developed. Three different pipelines, rigid or flexible, can be tested simultaneously. Critical factors in heat leak measurements include eliminating heat transfer at end connections and obtaining proper liquid saturation condition. Effects due to variations in the external ambient conditions like wind, humidity, and solar radiation must be minimized. The static method of liquid nitrogen evaporation has been demonstrated, but the apparatus can be adapted for dynamic testing with cryogens, chilled water, or other working fluids. This technology is suited for the development of an industry standard test apparatus and method. Examples of the heat transfer data from testing commercially available pipelines are given. Prototype pipelines are currently being tested and evaluated at the Cryogenics Test Laboratory of NASA Kennedy Space Center.

  8. Adaptable System for Vehicle Health and Usage Monitoring

    NASA Technical Reports Server (NTRS)

    Woodart, Stanley E.; Woodman, Keith L.; Coffey, Neil C.; Taylor, Bryant D.

    2005-01-01

    Aircraft and other vehicles are often kept in service beyond their original design lives. As they age, they become susceptible to system malfunctions and fatigue. Unlike future aircraft that will include health-monitoring capabilities as integral parts in their designs, older aircraft have not been so equipped. The Adaptable Vehicle Health and Usage Monitoring System is designed to be retrofitted into a preexisting fleet of military and commercial aircraft, ships, or ground vehicles to provide them with state-of-the-art health- and usage-monitoring capabilities. The monitoring system is self-contained, and the integration of it into existing systems entails limited intrusion. In essence, it has bolt-on/ bolt-off simplicity that makes it easy to install on any preexisting vehicle or structure. Because the system is completely independent of the vehicle, it can be certified for airworthiness as an independent system. The purpose served by the health-monitoring system is to reduce vehicle operating costs and to increase safety and reliability. The monitoring system is a means to identify damage to, or deterioration of, vehicle subsystems, before such damage or deterioration becomes costly and/or disastrous. Frequent monitoring of a vehicle enables identification of the embryonic stages of damage or deterioration. The knowledge thus gained can be used to correct anomalies while they are still somewhat minor. Maintenance can be performed as needed, instead of having the need for maintenance identified during cyclic inspections that take vehicles off duty even when there are no maintenance problems. Measurements and analyses acquired by the health-monitoring system also can be used to analyze mishaps. Overall, vehicles can be made more reliable and kept on duty for longer times. Figure 1 schematically depicts the system as applied to a fleet of n vehicles. The system has three operational levels. All communication between system components is by use of wireless

  9. Fast calibration of high-order adaptive optics systems

    NASA Astrophysics Data System (ADS)

    Kasper, Markus; Fedrigo, Enrico; Looze, Douglas P.; Bonnet, Henri; Ivanescu, Liviu; Oberti, Sylvain

    2004-06-01

    We present a new method of calibrating adaptive optics systems that greatly reduces the required calibration time or, equivalently, improves the signal-to-noise ratio. The method uses an optimized actuation scheme with Hadamard patterns and does not scale with the number of actuators for a given noise level in the wave-front sensor channels. It is therefore highly desirable for high-order systems and/or adaptive secondary systems on a telescope without a Gregorian focal plane. In the latter case, the measurement noise is increased by the effects of the turbulent atmosphere when one is calibrating on a natural guide star.

  10. Fast calibration of high-order adaptive optics systems.

    PubMed

    Kasper, Markus; Fedrigo, Enrico; Looze, Douglas P; Bonnet, Henri; Ivanescu, Liviu; Oberti, Sylvain

    2004-06-01

    We present a new method of calibrating adaptive optics systems that greatly reduces the required calibration time or, equivalently, improves the signal-to-noise ratio. The method uses an optimized actuation scheme with Hadamard patterns and does not scale with the number of actuators for a given noise level in the wavefront sensor channels. It is therefore highly desirable for high-order systems and/or adaptive secondary systems on a telescope without a Gregorian focal plane. In the latter case, the measurement noise is increased by the effects of the turbulent atmosphere when one is calibrating on a natural guide star. PMID:15191182

  11. Test Telemetry And Command System (TTACS)

    NASA Astrophysics Data System (ADS)

    Fogel, Alvin J.

    1994-11-01

    The Jet Propulsion Laboratory has developed a multimission Test Telemetry and Command System (TTACS) which provides a multimission telemetry and command data system in a spacecraft test environment. TTACS reuses, in the spacecraft test environment, components of the same data system used for flight operations; no new software is developed for the spacecraft test environment. Additionally, the TTACS is transportable to any spacecraft test site, including the launch site. The TTACS is currently operational in the Galileo spacecraft testbed; it is also being provided to support the Cassini and Mars Surveyor Program projects. Minimal personnel data system training is required in the transition from pre-launch spacecraft test to post-launch flight operations since test personnel are already familiar with the data system's operation. Additionally, data system components, e.g. data display, can be reused to support spacecraft software development; and the same data system components will again be reused during the spacecraft integration and system test phases. TTACS usage also results in early availability of spacecraft data to data system development and, as a result, early data system development feedback to spacecraft system developers. The TTACS consists of a multimission spacecraft support equipment interface and components of the multimission telemetry and command software adapted for a specific project. The TTACS interfaces to the spacecraft, e.g., Command Data System (CDS), support equipment. The TTACS telemetry interface to the CDS support equipment performs serial (RS-422)-to-ethernet conversion at rates between 1 bps and 1 mbps, telemetry data blocking and header generation, guaranteed data transmission to the telemetry data system, and graphical downlink routing summary and control. The TTACS command interface to the CDS support equipment is nominally a command file transferred in non-real-time via ethernet. The CDS support equipment is responsible for

  12. Test Telemetry And Command System (TTACS)

    NASA Technical Reports Server (NTRS)

    Fogel, Alvin J.

    1994-01-01

    The Jet Propulsion Laboratory has developed a multimission Test Telemetry and Command System (TTACS) which provides a multimission telemetry and command data system in a spacecraft test environment. TTACS reuses, in the spacecraft test environment, components of the same data system used for flight operations; no new software is developed for the spacecraft test environment. Additionally, the TTACS is transportable to any spacecraft test site, including the launch site. The TTACS is currently operational in the Galileo spacecraft testbed; it is also being provided to support the Cassini and Mars Surveyor Program projects. Minimal personnel data system training is required in the transition from pre-launch spacecraft test to post-launch flight operations since test personnel are already familiar with the data system's operation. Additionally, data system components, e.g. data display, can be reused to support spacecraft software development; and the same data system components will again be reused during the spacecraft integration and system test phases. TTACS usage also results in early availability of spacecraft data to data system development and, as a result, early data system development feedback to spacecraft system developers. The TTACS consists of a multimission spacecraft support equipment interface and components of the multimission telemetry and command software adapted for a specific project. The TTACS interfaces to the spacecraft, e.g., Command Data System (CDS), support equipment. The TTACS telemetry interface to the CDS support equipment performs serial (RS-422)-to-ethernet conversion at rates between 1 bps and 1 mbps, telemetry data blocking and header generation, guaranteed data transmission to the telemetry data system, and graphical downlink routing summary and control. The TTACS command interface to the CDS support equipment is nominally a command file transferred in non-real-time via ethernet. The CDS support equipment is responsible for

  13. Adaptive Attitude Control System For Space Station

    NASA Technical Reports Server (NTRS)

    Boussalis, Dhemetrios; Bayard, David S.; Wang, Shyh J.

    1995-01-01

    Report presents theoretical foundation for attitude control system for proposed Space Station Freedom in orbit around Earth. Intended to maintain space station in torque equilibrium with designated axes of its structure aligned with local vertical, local along-trajectory horizontal, and local across-trajectory horizontal axes, respectively. System required to provide desired combination of control performance and stability in presence of disturbances (e.g., variations in masses of payloads, movements of astronauts and equipment, atmospheric drag, gravitational anomalies, and interactions with docking spacecraft).

  14. Advanced air revitalization system testing

    NASA Technical Reports Server (NTRS)

    Heppner, D. B.; Hallick, T. M.; Schubert, F. H.

    1983-01-01

    A previously developed experimental air revitalization system was tested cyclically and parametrically. One-button startup without manual interventions; extension by 1350 hours of tests with the system; capability for varying process air carbon dioxide partial pressure and humidity and coolant source for simulation of realistic space vehicle interfaces; dynamic system performance response on the interaction of the electrochemical depolarized carbon dioxide concentrator, the Sabatier carbon dioxide reduction subsystem, and the static feed water electrolysis oxygen generation subsystem, the carbon dioxide concentrator module with unitized core technology for the liquid cooled cell; and a preliminary design for a regenerative air revitalization system for the space station are discussed.

  15. Understanding leukemic hematopoiesis as a complex adaptive system

    PubMed Central

    Thomas, Xavier

    2015-01-01

    Normal and abnormal hematopoiesis is working as a complex adaptive system. From this perspective, the development and the behavior of hematopoietic cell lineages appear as a balance between normal and abnormal hematopoiesis in the setting of a functioning or malfunctioning microenvironment under the control of the immune system and the influence of hereditary and environmental events. PMID:26516407

  16. Design of Adaptive Hypermedia Learning Systems: A Cognitive Style Approach

    ERIC Educational Resources Information Center

    Mampadi, Freddy; Chen, Sherry Y.; Ghinea, Gheorghita; Chen, Ming-Puu

    2011-01-01

    In the past decade, a number of adaptive hypermedia learning systems have been developed. However, most of these systems tailor presentation content and navigational support solely according to students' prior knowledge. On the other hand, previous research suggested that cognitive styles significantly affect student learning because they refer to…

  17. Integrating Learning Styles into Adaptive E-Learning System

    ERIC Educational Resources Information Center

    Truong, Huong May

    2015-01-01

    This paper provides an overview and update on my PhD research project which focuses on integrating learning styles into adaptive e-learning system. The project, firstly, aims to develop a system to classify students' learning styles through their online learning behaviour. This will be followed by a study on the complex relationship between…

  18. Microcomputer Network for Computerized Adaptive Testing (CAT). [Final Report, FY81-83].

    ERIC Educational Resources Information Center

    Quan, Baldwin; And Others

    Computerized adaptive testing (CAT) offers the opportunity to replace paper-and-pencil aptitude tests such as the Armed Services Vocational Aptitude Battery with shorter, more accurate, and more secure computer-administered tests. Its potential advantages need to be verified by experimental administration of automated tests to military recruit…

  19. A Validity Comparison of Adaptive and Conventional Strategies for Mastery Testing.

    ERIC Educational Resources Information Center

    Kingsbury, G. Gage; Weiss, David J.

    Conventional mastery tests designed to make optimal mastery classifications were compared with fixed-length and variable-length adaptive mastery tests. Comparisons between the testing procedures were made across five content areas in an introductory biology course from tests administered to volunteers. The criterion was the student's standing in…

  20. A Comparison of Item-Selection Methods for Adaptive Tests with Content Constraints

    ERIC Educational Resources Information Center

    van der Linden, Wim J.

    2005-01-01

    In test assembly, a fundamental difference exists between algorithms that select a test sequentially or simultaneously. Sequential assembly allows us to optimize an objective function at the examinee's ability estimate, such as the test information function in computerized adaptive testing. But it leads to the non-trivial problem of how to realize…

  1. Multidimensional Computerized Adaptive Scholastic Aptitude Test Program Used for Grade 9 Students under Different Reviewing Test Conditions

    ERIC Educational Resources Information Center

    Khunkrai, Naruemon; Sawangboon, Tatsirin; Ketchatturat, Jatuphum

    2015-01-01

    The aim of this research is to study the accurate prediction of comparing test information and evaluation result by multidimensional computerized adaptive scholastic aptitude test program used for grade 9 students under different reviewing test conditions. Grade 9 students of the Secondary Educational Service Area Office in the North-east of…

  2. Climate change: Cropping system changes and adaptations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Climate change impacts the life of every person; however, there is little comprehensive understanding of the direct and indirect effects of climate change on agriculture. Since our food, feed, fiber, and fruit is derived from agricultural systems, understanding the effects of changing temperature, p...

  3. Adaptive Device Context Based Mobile Learning Systems

    ERIC Educational Resources Information Center

    Pu, Haitao; Lin, Jinjiao; Song, Yanwei; Liu, Fasheng

    2011-01-01

    Mobile learning is e-learning delivered through mobile computing devices, which represents the next stage of computer-aided, multi-media based learning. Therefore, mobile learning is transforming the way of traditional education. However, as most current e-learning systems and their contents are not suitable for mobile devices, an approach for…

  4. The Moon System Adapted for Musical Notation.

    ERIC Educational Resources Information Center

    Jackson, Michael

    1987-01-01

    A means is presented for using William Moon's embossed symbols to represent musical notation for blind individuals, as an alternative to braille notation. The proposed system includes pitch symbols, octave indicators, duration symbols, accidentals, key signatures, rests, stress symbols, ornaments, and other symbols. (Author/JDD)

  5. Effects of adaptive task allocation on monitoring of automated systems

    NASA Technical Reports Server (NTRS)

    Parasuraman, R.; Mouloua, M.; Molloy, R.

    1996-01-01

    The effects of adaptive task allocation on monitoring for automation failure during multitask flight simulation were examined. Participants monitored an automated engine status task while simultaneously performing tracking and fuel management tasks over three 30-min sessions. Two methods of adaptive task allocation, both involving temporary return of the automated engine status task to the human operator ("human control"), were examined as a possible countermeasure to monitoring inefficiency. For the model-based adaptive group, the engine status task was allocated to all participants in the middle of the second session for 10 min, following which it was again returned to automation control. The same occurred for the performance-based adaptive group, but only if an individual participant's monitoring performance up to that point did not meet a specified criterion. For the nonadaptive control groups, the engine status task remained automated throughout the experiment. All groups had low probabilities of detection of automation failures for the first 40 min spent with automation. However, following the 10-min intervening period of human control, both adaptive groups detected significantly more automation failures during the subsequent blocks under automation control. The results show that adaptive task allocation can enhance monitoring of automated systems. Both model-based and performance-based allocation improved monitoring of automation. Implications for the design of automated systems are discussed.

  6. Clinical relevance of tests on bond strength, microleakage and marginal adaptation.

    PubMed

    Heintze, Siegward D

    2013-01-01

    Dental adhesive systems should provide a variety of capabilities, such as bonding of artificial materials to dentin and enamel, sealing of dentinal tubules, reduction of post-operative sensitivity and marginal sealing to reduce marginal staining and caries. In the laboratory, numerous surrogate parameters that should predict the performance of different materials, material combinations and operative techniques are assessed. These surrogate parameters include bond strength tests of various kinds, evaluation of microleakage with tracer penetration between restorative and tooth, two-dimensional analysis of marginal quality with microscopes and mapping of the micromorphology of the bonding interface. Many of these tests are not systematically validated and show therefore different results between different research institutes. The correlation with clinical phenomena has only partly been established to date. There is some evidence, that macrotensile and microtensile bond strength tests correlate better with clinical retention of cervical restorations than macroshear and microshear bond tests but only if data from different test institutes are pooled. Also there is some evidence that marginal adaptation has a moderate correlation in cervical restorations with clinical retention and in Class II restorations (proximal enamel) with clinical marginal staining. There is moderate evidence that microleakage tests with dye penetration does not correlate with any of the clinical parameters (post-operative hypersensitivity, retention, marginal staining). A rationale which helps the researcher to select and apply clinically relevant test methods in the laboratory is presented in the paper. PMID:22920539

  7. Adapting the Critical Thinking Assessment Test for Palestinian Universities

    ERIC Educational Resources Information Center

    Basha, Sami; Drane, Denise; Light, Gregory

    2016-01-01

    Critical thinking is a key learning outcome for Palestinian students. However, there are no validated critical thinking tests in Arabic. Suitability of the US developed Critical Thinking Assessment Test (CAT) for use in Palestine was assessed. The test was piloted with university students in English (n = 30) and 4 questions were piloted in Arabic…

  8. Using Out-of-Level Items in Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Wei, Hua; Lin, Jie

    2015-01-01

    Out-of-level testing refers to the practice of assessing a student with a test that is intended for students at a higher or lower grade level. Although the appropriateness of out-of-level testing for accountability purposes has been questioned by educators and policymakers, incorporating out-of-level items in formative assessments for accurate…

  9. Lessons from Adaptive Level One Accelerator (ALOA) System Implementation

    NASA Technical Reports Server (NTRS)

    Patel, Umesh D.; Brambora, Clifford; Ghuman, Parminder; Day, John H. (Technical Monitor)

    2001-01-01

    The Adaptive Level One Accelerator (ALOA) system was developed as part of the Earth Science Data and Information System (ESDIS) project. The reconfigurable computing technologies were investigated for Level 1 satellite telemetry data processing to achieve computing acceleration and cost reduction for the next-generation Level 1 data processing systems. The MODIS instrument calibration algorithm was implemented using reconfigurable a computer. The system development process and the lessons learned throughout the design cycle are summarized in this paper.

  10. Method and system for environmentally adaptive fault tolerant computing

    NASA Technical Reports Server (NTRS)

    Copenhaver, Jason L. (Inventor); Jeremy, Ramos (Inventor); Wolfe, Jeffrey M. (Inventor); Brenner, Dean (Inventor)

    2010-01-01

    A method and system for adapting fault tolerant computing. The method includes the steps of measuring an environmental condition representative of an environment. An on-board processing system's sensitivity to the measured environmental condition is measured. It is determined whether to reconfigure a fault tolerance of the on-board processing system based in part on the measured environmental condition. The fault tolerance of the on-board processing system may be reconfigured based in part on the measured environmental condition.

  11. Framework for Adaptable Operating and Runtime Systems: Final Project Report

    SciTech Connect

    Patrick G. Bridges

    2012-02-01

    In this grant, we examined a wide range of techniques for constructing high-performance con gurable system software for HPC systems and its application to DOE-relevant problems. Overall, research and development on this project focused in three specifc areas: (1) software frameworks for constructing and deploying con gurable system software, (2) applcation of these frameworks to HPC-oriented adaptable networking software, (3) performance analysis of HPC system software to understand opportunities for performance optimization.

  12. Adaptive control with an expert system based supervisory level. Thesis

    NASA Technical Reports Server (NTRS)

    Sullivan, Gerald A.

    1991-01-01

    Adaptive control is presently one of the methods available which may be used to control plants with poorly modelled dynamics or time varying dynamics. Although many variations of adaptive controllers exist, a common characteristic of all adaptive control schemes, is that input/output measurements from the plant are used to adjust a control law in an on-line fashion. Ideally the adjustment mechanism of the adaptive controller is able to learn enough about the dynamics of the plant from input/output measurements to effectively control the plant. In practice, problems such as measurement noise, controller saturation, and incorrect model order, to name a few, may prevent proper adjustment of the controller and poor performance or instability result. In this work we set out to avoid the inadequacies of procedurally implemented safety nets, by introducing a two level control scheme in which an expert system based 'supervisor' at the upper level provides all the safety net functions for an adaptive controller at the lower level. The expert system is based on a shell called IPEX, (Interactive Process EXpert), that we developed specifically for the diagnosis and treatment of dynamic systems. Some of the more important functions that the IPEX system provides are: (1) temporal reasoning; (2) planning of diagnostic activities; and (3) interactive diagnosis. Also, because knowledge and control logic are separate, the incorporation of new diagnostic and treatment knowledge is relatively simple. We note that the flexibility available in the system to express diagnostic and treatment knowledge, allows much greater functionality than could ever be reasonably expected from procedural implementations of safety nets. The remainder of this chapter is divided into three sections. In section 1.1 we give a detailed review of the literature in the area of supervisory systems for adaptive controllers. In particular, we describe the evolution of safety nets from simple ad hoc techniques, up

  13. Space Fission System Test Effectiveness

    SciTech Connect

    Houts, Mike; Schmidt, Glen L.; Van Dyke, Melissa; Godfroy, Tom; Martin, James; Bragg-Sitton, Shannon; Dickens, Ricky; Salvail, Pat; Harper, Roger

    2004-02-04

    Space fission technology has the potential to enable rapid access to any point in the solar system. If fission propulsion systems are to be developed to their full potential, however, near-term customers need to be identified and initial fission systems successfully developed, launched, and utilized. One key to successful utilization is to develop reactor designs that are highly testable. Testable reactor designs have a much higher probability of being successfully converted from paper concepts to working space hardware than do designs which are difficult or impossible to realistically test. ''Test Effectiveness'' is one measure of the ability to realistically test a space reactor system. The objective of this paper is to discuss test effectiveness as applied to the design, development, flight qualification, and acceptance testing of space fission systems. The ability to perform highly effective testing would be particularly important to the success of any near-term mission, such as NASA's Jupiter Icy Moons Orbiter, the first mission under study within NASA's Project Prometheus, the Nuclear Systems Program.

  14. Development and Flight Testing of an Adaptable Vehicle Health-Monitoring Architecture

    NASA Technical Reports Server (NTRS)

    Woodard, Stanley E.; Coffey, Neil C.; Gonzalez, Guillermo A.; Woodman, Keith L.; Weathered, Brenton W.; Rollins, Courtney H.; Taylor, B. Douglas; Brett, Rube R.

    2003-01-01

    Development and testing of an adaptable wireless health-monitoring architecture for a vehicle fleet is presented. It has three operational levels: one or more remote data acquisition units located throughout the vehicle; a command and control unit located within the vehicle; and a terminal collection unit to collect analysis results from all vehicles. Each level is capable of performing autonomous analysis with a trained adaptable expert system. The remote data acquisition unit has an eight channel programmable digital interface that allows the user discretion for choosing type of sensors; number of sensors, sensor sampling rate, and sampling duration for each sensor. The architecture provides framework for a tributary analysis. All measurements at the lowest operational level are reduced to provide analysis results necessary to gauge changes from established baselines. These are then collected at the next level to identify any global trends or common features from the prior level. This process is repeated until the results are reduced at the highest operational level. In the framework, only analysis results are forwarded to the next level to reduce telemetry congestion. The system's remote data acquisition hardware and non-analysis software have been flight tested on the NASA Langley B757's main landing gear.

  15. Design, fabrication, and testing of SMA-enabled adaptive chevrons for jet noise reduction

    NASA Astrophysics Data System (ADS)

    Turner, Travis L.; Buehrle, Ralph D.; Cano, Roberto J.; Fleming, Gary A.

    2004-07-01

    This study presents the status and results from an effort to design, fabricate, and test an adaptive jet engine chevron concept based upon embedding shape memory alloy (SMA) actuators in a composite laminate, termed a SMA hybrid composite (SMAHC). The approach for fabricating the adaptive SMAHC chevrons involves embedding prestrained Nitinol actuators on one side of the mid-plane of the composite laminate such that thermal excitation generates a thermal moment and deflects the structure. A glass-epoxy pre-preg/Nitinol ribbon material system and a vacuum hot press consolidation approach are employed. A versatile test system for control and measurement of the chevron deflection performance is described. Projection moire interferometry (PMI) is used for global deformation measurement and infrared (IR) thermography is used for 2-D temperature measurement and feedback control. A recently commercialized constitutive model for SMA and SMAHC materials is used in the finite element code ABAQUS to perform nonlinear static analysis of the chevron prototypes. Excellent agreement is achieved between the predicted and measured chevron deflection performance, thereby validating the design tool. Although the performance results presented in this paper fall short of the requirement, the concept is proven and an approach for achieving the performance objectives is evident.

  16. Design, Fabrication, and Testing of SMA Enabled Adaptive Chevrons for Jet Noise Reduction

    NASA Technical Reports Server (NTRS)

    Turner, Travis L.; Buehrle, Ralph D.; Cano, Roberto J.; Fleming, Gary A.

    2004-01-01

    This study presents the status and results from an effort to design, fabricate, and test an adaptive jet engine chevron concept based upon embedding shape memory alloy (SMA) actuators in a composite laminate, termed a SMA hybrid composite (SMAHC). The approach for fabricating the adaptive SMAHC chevrons involves embedding prestrained Nitinol actuators on one side of the mid-plane of the composite laminate such that thermal excitation generates a thermal moment and deflects the structure. A glass-epoxy pre-preg/Nitinol ribbon material system and a vacuum hot press consolidation approach are employed. A versatile test system for control and measurement of the chevron deflection performance is described. Projection moire interferometry (PMI) is used for global deformation measurement and infrared (IR) thermography is used for 2-D temperature measurement and feedback control. A recently commercialized constitutive model for SMA and SMAHC materials is used in the finite element code ABAQUS to perform nonlinear static analysis of the chevron prototypes. Excellent agreement is achieved between the predicted and measured chevron deflection performance, thereby validating the design tool. Although the performance results presented in this paper fall short of the requirement, the concept is proven and an approach for achieving the performance objectives is evident.

  17. Adaptive Management of Computing and Network Resources for Spacecraft Systems

    NASA Technical Reports Server (NTRS)

    Pfarr, Barbara; Welch, Lonnie R.; Detter, Ryan; Tjaden, Brett; Huh, Eui-Nam; Szczur, Martha R. (Technical Monitor)

    2000-01-01

    It is likely that NASA's future spacecraft systems will consist of distributed processes which will handle dynamically varying workloads in response to perceived scientific events, the spacecraft environment, spacecraft anomalies and user commands. Since all situations and possible uses of sensors cannot be anticipated during pre-deployment phases, an approach for dynamically adapting the allocation of distributed computational and communication resources is needed. To address this, we are evolving the DeSiDeRaTa adaptive resource management approach to enable reconfigurable ground and space information systems. The DeSiDeRaTa approach embodies a set of middleware mechanisms for adapting resource allocations, and a framework for reasoning about the real-time performance of distributed application systems. The framework and middleware will be extended to accommodate (1) the dynamic aspects of intra-constellation network topologies, and (2) the complete real-time path from the instrument to the user. We are developing a ground-based testbed that will enable NASA to perform early evaluation of adaptive resource management techniques without the expense of first deploying them in space. The benefits of the proposed effort are numerous, including the ability to use sensors in new ways not anticipated at design time; the production of information technology that ties the sensor web together; the accommodation of greater numbers of missions with fewer resources; and the opportunity to leverage the DeSiDeRaTa project's expertise, infrastructure and models for adaptive resource management for distributed real-time systems.

  18. SDR implementation of the receiver of adaptive communication system

    NASA Astrophysics Data System (ADS)

    Skarzynski, Jacek; Darmetko, Marcin; Kozlowski, Sebastian; Kurek, Krzysztof

    2016-04-01

    The paper presents software implementation of a receiver forming a part of an adaptive communication system. The system is intended for communication with a satellite placed in a low Earth orbit (LEO). The ability of adaptation is believed to increase the total amount of data transmitted from the satellite to the ground station. Depending on the signal-to-noise ratio (SNR) of the received signal, adaptive transmission is realized using different transmission modes, i.e., different modulation schemes (BPSK, QPSK, 8-PSK, and 16-APSK) and different convolutional code rates (1/2, 2/3, 3/4, 5/6, and 7/8). The receiver consists of a software-defined radio (SDR) module (National Instruments USRP-2920) and a multithread reception software running on Windows operating system. In order to increase the speed of signal processing, the software takes advantage of single instruction multiple data instructions supported by x86 processor architecture.

  19. ADAPTIVE CLEARANCE CONTROL SYSTEMS FOR TURBINE ENGINES

    NASA Technical Reports Server (NTRS)

    Blackwell, Keith M.

    2004-01-01

    The Controls and Dynamics Technology Branch at NASA Glenn Research Center primarily deals in developing controls, dynamic models, and health management technologies for air and space propulsion systems. During the summer of 2004 I was granted the privilege of working alongside professionals who were developing an active clearance control system for commercial jet engines. Clearance, the gap between the turbine blade tip and the encompassing shroud, increases as a result of wear mechanisms and rubbing of the turbine blades on shroud. Increases in clearance cause larger specific fuel consumption (SFC) and loss of efficient air flow. This occurs because, as clearances increase, the engine must run hotter and bum more fuel to achieve the same thrust. In order to maintain efficiency, reduce fuel bum, and reduce exhaust gas temperature (EGT), the clearance must be accurately controlled to gap sizes no greater than a few hundredths of an inch. To address this problem, NASA Glenn researchers have developed a basic control system with actuators and sensors on each section of the shroud. Instead of having a large uniform metal casing, there would be sections of the shroud with individual sensors attached internally that would move slightly to reform and maintain clearance. The proposed method would ultimately save the airline industry millions of dollars.

  20. An Approach to V&V of Embedded Adaptive Systems

    NASA Technical Reports Server (NTRS)

    Liu, Yan; Yerramalla, Sampath; Fuller, Edgar; Cukic, Bojan; Gururajan, Srikaruth

    2004-01-01

    Rigorous Verification and Validation (V&V) techniques are essential for high assurance systems. Lately, the performance of some of these systems is enhanced by embedded adaptive components in order to cope with environmental changes. Although the ability of adapting is appealing, it actually poses a problem in terms of V&V. Since uncertainties induced by environmental changes have a significant impact on system behavior, the applicability of conventional V&V techniques is limited. In safety-critical applications such as flight control system, the mechanisms of change must be observed, diagnosed, accommodated and well understood prior to deployment. In this paper, we propose a non-conventional V&V approach suitable for online adaptive systems. We apply our approach to an intelligent flight control system that employs a particular type of Neural Networks (NN) as the adaptive learning paradigm. Presented methodology consists of a novelty detection technique and online stability monitoring tools. The novelty detection technique is based on Support Vector Data Description that detects novel (abnormal) data patterns. The Online Stability Monitoring tools based on Lyapunov's Stability Theory detect unstable learning behavior in neural networks. Cases studies based on a high fidelity simulator of NASA's Intelligent Flight Control System demonstrate a successful application of the presented V&V methodology. ,

  1. Development and Flight Testing of an Adaptive Vehicle Health-Monitoring Architecture

    NASA Technical Reports Server (NTRS)

    Woodard, Stanley E.; Coffey, Neil C.; Gonzalez, Guillermo A.; Taylor, B. Douglas; Brett, Rube R.; Woodman, Keith L.; Weathered, Brenton W.; Rollins, Courtney H.

    2002-01-01

    On going development and testing of an adaptable vehicle health-monitoring architecture is presented. The architecture is being developed for a fleet of vehicles. It has three operational levels: one or more remote data acquisition units located throughout the vehicle; a command and control unit located within the vehicle, and, a terminal collection unit to collect analysis results from all vehicles. Each level is capable of performing autonomous analysis with a trained expert system. The expert system is parameterized, which makes it adaptable to be trained to both a user's subject reasoning and existing quantitative analytic tools. Communication between all levels is done with wireless radio frequency interfaces. The remote data acquisition unit has an eight channel programmable digital interface that allows the user discretion for choosing type of sensors; number of sensors, sensor sampling rate and sampling duration for each sensor. The architecture provides framework for a tributary analysis. All measurements at the lowest operational level are reduced to provide analysis results necessary to gauge changes from established baselines. These are then collected at the next level to identify any global trends or common features from the prior level. This process is repeated until the results are reduced at the highest operational level. In the framework, only analysis results are forwarded to the next level to reduce telemetry congestion. The system's remote data acquisition hardware and non-analysis software have been flight tested on the NASA Langley B757's main landing gear. The flight tests were performed to validate the following: the wireless radio frequency communication capabilities of the system, the hardware design, command and control; software operation and, data acquisition, storage and retrieval.

  2. A Strategy for Controlling Item Exposure in Multidimensional Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Lee, Yi-Hsuan; Ip, Edward H.; Fuh, Cheng-Der

    2008-01-01

    Although computerized adaptive tests have enjoyed tremendous growth, solutions for important problems remain unavailable. One problem is the control of item exposure rate. Because adaptive algorithms are designed to select optimal items, they choose items with high discriminating power. Thus, these items are selected more often than others,…

  3. Artificial frame filling using adaptive neural fuzzy inference system for particle image velocimetry dataset

    NASA Astrophysics Data System (ADS)

    Akdemir, Bayram; Doǧan, Sercan; Aksoy, Muharrem H.; Canli, Eyüp; Özgören, Muammer

    2015-03-01

    Liquid behaviors are very important for many areas especially for Mechanical Engineering. Fast camera is a way to observe and search the liquid behaviors. Camera traces the dust or colored markers travelling in the liquid and takes many pictures in a second as possible as. Every image has large data structure due to resolution. For fast liquid velocity, there is not easy to evaluate or make a fluent frame after the taken images. Artificial intelligence has much popularity in science to solve the nonlinear problems. Adaptive neural fuzzy inference system is a common artificial intelligence in literature. Any particle velocity in a liquid has two dimension speed and its derivatives. Adaptive Neural Fuzzy Inference System has been used to create an artificial frame between previous and post frames as offline. Adaptive neural fuzzy inference system uses velocities and vorticities to create a crossing point vector between previous and post points. In this study, Adaptive Neural Fuzzy Inference System has been used to fill virtual frames among the real frames in order to improve image continuity. So this evaluation makes the images much understandable at chaotic or vorticity points. After executed adaptive neural fuzzy inference system, the image dataset increase two times and has a sequence as virtual and real, respectively. The obtained success is evaluated using R2 testing and mean squared error. R2 testing has a statistical importance about similarity and 0.82, 0.81, 0.85 and 0.8 were obtained for velocities and derivatives, respectively.

  4. Situational adapting system supporting team situation awareness

    NASA Astrophysics Data System (ADS)

    Helldin, Tove; Erlandsson, Tina; Niklasson, Lars; Falkman, Göran

    2010-10-01

    Military fighter pilots have to make suitable decisions fast in an environment where continuously increasing flows of information from sensors, team members and databases are provided. Not only do the huge amounts of data aggravate the pilots' decision making process: time-pressure, presence of uncertain data and high workload are factors that can worsen the performance of pilot decision making. In this paper, initial ideas of how to support the pilots accomplishing their tasks are presented. Results from interviews with two fighter pilots are described as well as a discussion about how these results can guide the design of a military fighter pilot decision support system, with focus on team cooperation.

  5. Adaptive mass expulsion attitude control system

    NASA Technical Reports Server (NTRS)

    Rodden, John J. (Inventor); Stevens, Homer D. (Inventor); Carrou, Stephane (Inventor)

    2001-01-01

    An attitude control system and method operative with a thruster controls the attitude of a vehicle carrying the thruster, wherein the thruster has a valve enabling the formation of pulses of expelled gas from a source of compressed gas. Data of the attitude of the vehicle is gathered, wherein the vehicle is located within a force field tending to orient the vehicle in a first attitude different from a desired attitude. The attitude data is evaluated to determine a pattern of values of attitude of the vehicle in response to the gas pulses of the thruster and in response to the force field. The system and the method maintain the attitude within a predetermined band of values of attitude which includes the desired attitude. Computation circuitry establishes an optimal duration of each of the gas pulses based on the pattern of values of attitude, the optimal duration providing for a minimal number of opening and closure operations of the valve. The thruster is operated to provide gas pulses having the optimal duration.

  6. Adaptive load sharing in heterogeneous distributed systems

    NASA Astrophysics Data System (ADS)

    Mirchandaney, Ravi; Towsley, Don; Stankovic, John A.

    1990-08-01

    In this paper, we study the performance characteristics of simple load sharing algorithms for heterogeneous distributed systems. We assume that nonnegligible delays are encountered in transferring jobs from one node to another. We analyze the effects of these delays on the performance of two threshold-based algorithms called Forward and Reverse. We formulate queuing theoretic models for each of the algorithms operating in heterogeneous systems under the assumption that the job arrival process at each node in Poisson and the service times and job transfer times are exponentially distributed. The models are solved using the Matrix-Geometric solution technique. These models are used to study the effects of different parameters and algorithm variations on the mean job response time: e.g., the effects of varying the thresholds, the impact of changing the probe limit, the impact of biasing the probing, and the optimal response times over a large range of loads and delays. Wherever relevant, the results of the models are compared with the M/M/ 1 model, representing no load balancing (hereafter referred to as NLB), and the M/M/K model, which is an achievable lower bound (hereafter referred to as LB).

  7. Adaptive network models of collective decision making in swarming systems.

    PubMed

    Chen, Li; Huepe, Cristián; Gross, Thilo

    2016-08-01

    We consider a class of adaptive network models where links can only be created or deleted between nodes in different states. These models provide an approximate description of a set of systems where nodes represent agents moving in physical or abstract space, the state of each node represents the agent's heading direction, and links indicate mutual awareness. We show analytically that the adaptive network description captures a phase transition to collective motion in some swarming systems, such as the Vicsek model, and that the properties of this transition are determined by the number of states (discrete heading directions) that can be accessed by each agent. PMID:27627342

  8. Open loop liquid crystal adaptive optics systems: progresses and results

    NASA Astrophysics Data System (ADS)

    Cao, Zhao-liang; Mu, Quan-quan; Xu, Huan-yu; Zhang, Pei-guang; Yao, Li-shuang; Xuan, Li

    2015-10-01

    Liquid crystal wavefront corrector (LCWFC) is one of the most attractive wavefront correction devices for adaptive optics system. The main disadvantages for conventional nematic LCWFC are polarization dependence and narrow working waveband. In this paper, a polarized beam splitter (PBS) based open loop optical design and an optimized energy splitting method was used to overcome these problems respectively. The results indicate that the open loop configuration was suitable for LCWFC and the novel energy splitting method can significantly improve the detection capability of the liquid crystal adaptive optics system.

  9. Emergent “quantum” theory in complex adaptive systems

    NASA Astrophysics Data System (ADS)

    Minic, Djordje; Pajevic, Sinisa

    2016-03-01

    Motivated by the question of stability, in this paper we argue that an effective quantum-like theory can emerge in complex adaptive systems. In the concrete example of stochastic Lotka-Volterra dynamics, the relevant effective “Planck constant” associated with such emergent “quantum” theory has the dimensions of the square of the unit of time. Such an emergent quantum-like theory has inherently nonclassical stability as well as coherent properties that are not, in principle, endangered by thermal fluctuations and therefore might be of crucial importance in complex adaptive systems.

  10. A portable solar adaptive optics system: software and laboratory developments

    NASA Astrophysics Data System (ADS)

    Ren, Deqing; Penn, Matt; Plymate, Claude; Wang, Haimin; Zhang, Xi; Dong, Bing; Brown, Nathan; Denio, Andrew

    2010-07-01

    We present our recent process on a portable solar adaptive Optics system, which is aimed for diffraction-limited imaging in the 1.0 ~ 5.0-μm infrared wavelength range with any solar telescope with an aperture size up to 1.6 meters. The realtime wave-front sensing, image processing and computation are based on a commercial multi-core personal computer. The software is developed in LabVIEW. Combining the power of multi-core imaging processing and LabVIEW parallel programming, we show that our solar adaptive optics can achieve excellent performance that is competitive with other systems. In addition, the LabVIEW's block diagram based programming is especially suitable for rapid development of a prototype system, which makes a low-cost and high-performance system possible. Our adaptive optics system is flexible; it can work with any telescope with or without central obstruction with any aperture size in the range of 0.6~1.6 meters. In addition, the whole system is compact and can be brought to a solar observatory to perform associated scientific observations. According to our knowledge, this is the first adaptive optics that adopts the LabVIEW high-level programming language with a multi-core commercial personal computer, and includes the unique features discussed above.

  11. Adaptive Modeling of the International Space Station Electrical Power System

    NASA Technical Reports Server (NTRS)

    Thomas, Justin Ray

    2007-01-01

    Software simulations provide NASA engineers the ability to experiment with spacecraft systems in a computer-imitated environment. Engineers currently develop software models that encapsulate spacecraft system behavior. These models can be inaccurate due to invalid assumptions, erroneous operation, or system evolution. Increasing accuracy requires manual calibration and domain-specific knowledge. This thesis presents a method for automatically learning system models without any assumptions regarding system behavior. Data stream mining techniques are applied to learn models for critical portions of the International Space Station (ISS) Electrical Power System (EPS). We also explore a knowledge fusion approach that uses traditional engineered EPS models to supplement the learned models. We observed that these engineered EPS models provide useful background knowledge to reduce predictive error spikes when confronted with making predictions in situations that are quite different from the training scenarios used when learning the model. Evaluations using ISS sensor data and existing EPS models demonstrate the success of the adaptive approach. Our experimental results show that adaptive modeling provides reductions in model error anywhere from 80% to 96% over these existing models. Final discussions include impending use of adaptive modeling technology for ISS mission operations and the need for adaptive modeling in future NASA lunar and Martian exploration.

  12. Programmable, automated transistor test system

    NASA Technical Reports Server (NTRS)

    Truong, L. V.; Sundburg, G. R.

    1986-01-01

    A programmable, automated transistor test system was built to supply experimental data on new and advanced power semiconductors. The data will be used for analytical models and by engineers in designing space and aircraft electric power systems. A pulsed power technique was used at low duty cycles in a nondestructive test to examine the dynamic switching characteristic curves of power transistors in the 500 to 1000 V, 10 to 100 A range. Data collection, manipulation, storage, and output are operator interactive but are guided and controlled by the system software.

  13. Automated Portable Test (APT) System: overview and prospects

    NASA Technical Reports Server (NTRS)

    Bittner, A. C.; Smith, M. G.; Kennedy, R. S.; Staley, C. F.; Harbeson, M. M.

    1985-01-01

    The Automated Portable Test (APT) System is a notebook-sized, computer-based, human-performance and subjective-status assessment system. It is now being used in a wide range of environmental studies (e.g., simulator aftereffects, flight tests, drug effects, and hypoxia). Three questionnaires and 15 performance tests have been implemented, and the adaptation of 30 more tests is underway or is planned. The APT System is easily transportable, is inexpensive, and has the breadth of expansion options required for field and laboratory applications. The APT System is a powerful and expandable tool for human assessment in remote and unusual environments.

  14. Decision-making in healthcare as a complex adaptive system.

    PubMed

    Kuziemsky, Craig

    2016-01-01

    Healthcare transformation requires a change in how the business of healthcare is done. Traditional decision-making approaches based on stable and predictable systems are inappropriate in healthcare because of the complex nature of healthcare delivery. This article reviews challenges to using traditional decision-making approaches in healthcare and how insight from Complex Adaptive Systems (CAS) could support healthcare management. The article also provides a system model to guide decision-making in healthcare as a CAS. PMID:26656389

  15. Selecting, adapting, and sustaining programs in health care systems.

    PubMed

    Zullig, Leah L; Bosworth, Hayden B

    2015-01-01

    Practitioners and researchers often design behavioral programs that are effective for a specific population or problem. Despite their success in a controlled setting, relatively few programs are scaled up and implemented in health care systems. Planning for scale-up is a critical, yet often overlooked, element in the process of program design. Equally as important is understanding how to select a program that has already been developed, and adapt and implement the program to meet specific organizational goals. This adaptation and implementation requires attention to organizational goals, available resources, and program cost. We assert that translational behavioral medicine necessitates expanding successful programs beyond a stand-alone research study. This paper describes key factors to consider when selecting, adapting, and sustaining programs for scale-up in large health care systems and applies the Knowledge to Action (KTA) Framework to a case study, illustrating knowledge creation and an action cycle of implementation and evaluation activities. PMID:25931825

  16. A dual-modal retinal imaging system with adaptive optics

    PubMed Central

    Meadway, Alexander; Girkin, Christopher A.; Zhang, Yuhua

    2013-01-01

    An adaptive optics scanning laser ophthalmoscope (AO-SLO) is adapted to provide optical coherence tomography (OCT) imaging. The AO-SLO function is unchanged. The system uses the same light source, scanning optics, and adaptive optics in both imaging modes. The result is a dual-modal system that can acquire retinal images in both en face and cross-section planes at the single cell level. A new spectral shaping method is developed to reduce the large sidelobes in the coherence profile of the OCT imaging when a non-ideal source is used with a minimal introduction of noise. The technique uses a combination of two existing digital techniques. The thickness and position of the traditionally named inner segment/outer segment junction are measured from individual photoreceptors. In-vivo images of healthy and diseased human retinas are demonstrated. PMID:24514529

  17. Some Tests For Adaptative Observations In Atmospheric Chemistry

    NASA Astrophysics Data System (ADS)

    Quélo, D.; Michelangeli, P.-A.; Sportisse, B.

    Air pollution forecast requires the coupling of models with data through data assimi- lation. A key question is related to the choice of observations (apart from technical require- ments). One wants to choose in a judicious way the species to observe, in which loca- tions and at which moments. The appropriate strategies are related to the techniques of "targeting" and "adaptative observations". We will investigate these techniques on a simplified model. The first part reports the influence of the slow-fast behaviour of atmospheric chem- istry. The second part presents the use of singular vectors and second-order adjoint techniques in order to determine the "optimal" choice of observations. This project is led in the framework of the INRIA Cooperative Research Action CO- MODE (COupling MOdels and Data in Environment).

  18. Performance of a MEMS-base Adaptive Optics Optical Coherency Tomography System

    SciTech Connect

    Evans, J; Zadwadzki, R J; Jones, S; Olivier, S; Opkpodu, S; Werner, J S

    2008-01-16

    We have demonstrated that a microelectrical mechanical systems (MEMS) deformable mirror can be flattened to < 1 nm RMS within controllable spatial frequencies over a 9.2-mm aperture making it a viable option for high-contrast adaptive optics systems (also known as Extreme Adaptive Optics). The Extreme Adaptive Optics Testbed at UC Santa Cruz is being used to investigate and develop technologies for high-contrast imaging, especially wavefront control. A phase shifting diffraction interferometer (PSDI) measures wavefront errors with sub-nm precision and accuracy for metrology and wavefront control. Consistent flattening, required testing and characterization of the individual actuator response, including the effects of dead and low-response actuators. Stability and repeatability of the MEMS devices was also tested. An error budget for MEMS closed loop performance will summarize MEMS characterization.

  19. Gain scheduling adaptive control strategies for HVDC systems to accommodate large disturbances

    SciTech Connect

    Reeve, J.; Sultan, M. )

    1994-02-01

    Techniques have been developed to permit the response of the controls for dc transmission systems to adapt to large system changes. A gain scheduling approach tunes the control as an on-line function of the effective short-circuit ratio and contingency indicators. The method has been tested by digital simulation, based on EMTP, of a back-to-back dc system. It has been found to be robust and control performance has been enhanced.

  20. An adaptive robust controller for time delay maglev transportation systems

    NASA Astrophysics Data System (ADS)

    Milani, Reza Hamidi; Zarabadipour, Hassan; Shahnazi, Reza

    2012-12-01

    For engineering systems, uncertainties and time delays are two important issues that must be considered in control design. Uncertainties are often encountered in various dynamical systems due to modeling errors, measurement noises, linearization and approximations. Time delays have always been among the most difficult problems encountered in process control. In practical applications of feedback control, time delay arises frequently and can severely degrade closed-loop system performance and in some cases, drives the system to instability. Therefore, stability analysis and controller synthesis for uncertain nonlinear time-delay systems are important both in theory and in practice and many analytical techniques have been developed using delay-dependent Lyapunov function. In the past decade the magnetic and levitation (maglev) transportation system as a new system with high functionality has been the focus of numerous studies. However, maglev transportation systems are highly nonlinear and thus designing controller for those are challenging. The main topic of this paper is to design an adaptive robust controller for maglev transportation systems with time-delay, parametric uncertainties and external disturbances. In this paper, an adaptive robust control (ARC) is designed for this purpose. It should be noted that the adaptive gain is derived from Lyapunov-Krasovskii synthesis method, therefore asymptotic stability is guaranteed.

  1. Self-characterization of linear and nonlinear adaptive optics systems.

    PubMed

    Hampton, Peter J; Conan, Rodolphe; Keskin, Onur; Bradley, Colin; Agathoklis, Pan

    2008-01-10

    We present methods used to determine the linear or nonlinear static response and the linear dynamic response of an adaptive optics (AO) system. This AO system consists of a nonlinear microelectromechanical systems deformable mirror (DM), a linear tip-tilt mirror (TTM), a control computer, and a Shack-Hartmann wavefront sensor. The system is modeled using a single-input-single-output structure to determine the one-dimensional transfer function of the dynamic response of the chain of system hardware. An AO system has been shown to be able to characterize its own response without additional instrumentation. Experimentally determined models are given for a TTM and a DM. PMID:18188192

  2. Testing of Lagrange multiplier damped least-squares control algorithm for woofer-tweeter adaptive optics

    PubMed Central

    Zou, Weiyao; Burns, Stephen A.

    2012-01-01

    A Lagrange multiplier-based damped least-squares control algorithm for woofer-tweeter (W-T) dual deformable-mirror (DM) adaptive optics (AO) is tested with a breadboard system. We show that the algorithm can complementarily command the two DMs to correct wavefront aberrations within a single optimization process: the woofer DM correcting the high-stroke, low-order aberrations, and the tweeter DM correcting the low-stroke, high-order aberrations. The optimal damping factor for a DM is found to be the median of the eigenvalue spectrum of the influence matrix of that DM. Wavefront control accuracy is maximized with the optimized control parameters. For the breadboard system, the residual wavefront error can be controlled to the precision of 0.03 μm in root mean square. The W-T dual-DM AO has applications in both ophthalmology and astronomy. PMID:22441462

  3. Water impact shock test system

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The basic objective was to design, manufacture, and install a shock test system which, in part, would have the ability to subject test articles weighing up to 1,000 pounds to both half sine and/or full sine pulses having peak levels of up to 50 G's with half sine pulse durations of 100 milliseconds or full sine period duration of 200 milliseconds. The tolerances associated with the aforementioned pulses were +20% and -10% for the peak levels and plus or minus 10% for the pulse durations. The subject shock test system was to be capable of accepting test article sizes of up to 4 feet by 4 feet mounting surface by 4 feet in length.

  4. An Adaptive Multi-agent System for Project Schedule Management

    NASA Astrophysics Data System (ADS)

    Shou, Yongyi; Lai, Changtao

    A multi-agent system is established for project schedule management, considering the need for adaptive and dynamic scheduling under uncertainty. The system is realized using Java. In the proposed system, three types of agents, namely activity agents, resource agents, and a monitoring agent, are designed. Duration and resource requirement self-learning operators are developed for activity agents in order to model the self-learning and adaptive capacities of an agent in its local environment; moreover, a monitoring operator is also presented for the monitoring agent. The system allows the user to set up simulation parameters or scheduling rules according to their own preferences. Simulation results from an example showed that the system is effective in supporting users' decision-making process.

  5. The adaptive secondary mirror for the Large Binocular Telescope: results of acceptance laboratory test

    NASA Astrophysics Data System (ADS)

    Riccardi, A.; Xompero, M.; Zanotti, D.; Busoni, L.; Del Vecchio, C.; Salinari, P.; Ranfagni, P.; Brusa Zappellini, G.; Biasi, R.; Andrighettoni, M.; Gallieni, D.; Anaclerio, E.; Martin, H. M.; Miller, S. M.

    2008-07-01

    The first of the two Gregorian Adaptive Secondary Mirror (ASM) units for the Large Binocular Telescope (LBT) has been fully integrated and tested for laboratory acceptance. The LBT unit represents the most advanced ASM device existing in hardware. The unit has 672 electro-magnetic force actuators to change the shape of the 1.6mm-thick and 911mm-diameter Zerodur shell. The actuators control the mirror figure using the position feedback from the internal metrology provided by co-located capacitive sensors. The on-board real-time control electronics has a parallel computational power of 163Gflop/s providing not only the internal control of the unit with a 72kHz loop but also the wavefront reconstruction for the 1kHz Adaptive Optics loop. The paper describes the final configuration of the system and reports the results of the characterization and optimization process together with the results of the laboratory acceptance tests.

  6. Computerized Adaptive Testing: The State of the Art in Assessment at Three Community Colleges.

    ERIC Educational Resources Information Center

    League for Innovation in the Community Coll., Laguna Hills, CA.

    A description is provided of the experiences of three community colleges in implementing computerized adaptive testing to assess the entry-level skills of students. Chapter 1 provides background information on the project, which utilized The College Board's Computerized Placement Tests (CPT's), a battery of untimed, individualized tests of reading…

  7. Adaptation of a Vocabulary Test from British Sign Language to American Sign Language

    ERIC Educational Resources Information Center

    Mann, Wolfgang; Roy, Penny; Morgan, Gary

    2016-01-01

    This study describes the adaptation process of a vocabulary knowledge test for British Sign Language (BSL) into American Sign Language (ASL) and presents results from the first round of pilot testing with 20 deaf native ASL signers. The web-based test assesses the strength of deaf children's vocabulary knowledge by means of different mappings of…

  8. The Influence of Item Calibration Error on Variable-Length Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Patton, Jeffrey M.; Cheng, Ying; Yuan, Ke-Hai; Diao, Qi

    2013-01-01

    Variable-length computerized adaptive testing (VL-CAT) allows both items and test length to be "tailored" to examinees, thereby achieving the measurement goal (e.g., scoring precision or classification) with as few items as possible. Several popular test termination rules depend on the standard error of the ability estimate, which in turn depends…

  9. An Efficiency Balanced Information Criterion for Item Selection in Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Han, Kyung T.

    2012-01-01

    Successful administration of computerized adaptive testing (CAT) programs in educational settings requires that test security and item exposure control issues be taken seriously. Developing an item selection algorithm that strikes the right balance between test precision and level of item pool utilization is the key to successful implementation…

  10. Adaptive and Qualitative Changes in Encoding Strategy with Experience: Evidence from the Test-Expectancy Paradigm

    ERIC Educational Resources Information Center

    Finley, Jason R.; Benjamin, Aaron S.

    2012-01-01

    Three experiments demonstrated learners' abilities to adaptively and qualitatively accommodate their encoding strategies to the demands of an upcoming test. Stimuli were word pairs. In Experiment 1, test expectancy was induced for either cued recall (of targets given cues) or free recall (of targets only) across 4 study-test cycles of the same…

  11. Hybrid Computerized Adaptive Testing: From Group Sequential Design to Fully Sequential Design

    ERIC Educational Resources Information Center

    Wang, Shiyu; Lin, Haiyan; Chang, Hua-Hua; Douglas, Jeff

    2016-01-01

    Computerized adaptive testing (CAT) and multistage testing (MST) have become two of the most popular modes in large-scale computer-based sequential testing. Though most designs of CAT and MST exhibit strength and weakness in recent large-scale implementations, there is no simple answer to the question of which design is better because different…

  12. Accelerated Desensitization and Adaptive Attitudes Interventions and Test Gains with Academic Probation Students

    ERIC Educational Resources Information Center

    Driscoll, Richard; Holt, Bruce; Hunter, Lori

    2005-01-01

    The study evaluates the test-gain benefits of an accelerated desensitization and adaptive attitudes intervention for test-anxious students. College students were screened for high test anxiety. Twenty anxious students, half of them on academic probation, were assigned to an Intervention or to a minimal treatment Control group. The Intervention was…

  13. Reveal for Salmonella test system.

    PubMed

    Bird, C B; Miller, R L; Miller, B M

    1999-01-01

    The Reveal for Salmonella (RSS) test system is a presumptive qualitative test that detects the presence of Salmonella organisms in foods within 21 h total testing time, allowing the user to release negative products 24 h earlier than when using other rapid test kits. Foods are enriched with a proprietary resuscitation medium called Revive and then selectively enriched with either Selenite Cystine or Rappaport-Vassiliadis selective media. The enriched culture is used to inoculate the RSS detection device, which initiates a lateral flow through a reagent zone containing anti-Salmonella antibodies conjugated to colloidal gold particles that capture antigens present in the culture. The antigen-antibody complex migrates farther and is captured by an additional anti-Salmonella antibody, causing the colloidal gold to precipitate and form a visual line, indicating a positive result. A procedural control line also will form regardless of the presence of Salmonella organisms to indicate the test is working properly. Existing AOAC Official Methods for Salmonella organisms require a 48 h enrichment before testing. Hence, a food product has to be held before release, adding extra cost to the company and the consumer. The RSS test system was evaluated by quantitative spiking studies. Although AOAC encourages inclusion of naturally contaminated foods, almost all microbiological AOAC validation studies have been performed with artificially contaminated foods for absolute control over the study. The RSS test system is designed to test many food types for Salmonella organisms and has a limit of detection of 5-10 colony-forming units (cfu)/25 g with a false-negative rate of < 1% and a false-positive rate of < 5.0%. It showed an 81% overall agreement with the traditional procedure of the U.S. Department of Agriculture's Food Safety Inspection Service. PMID:10367381

  14. Test report - caustic addition system operability test procedure

    SciTech Connect

    Parazin, R.E.

    1995-10-13

    This Operability Test Report documents the test results of test procedure WHC-SD-WM-OTP-167 ``Caustic Addition System Operability Test Procedure``. The Objective of the test was to verify the operability of the 241-AN-107 Caustic Addition System. The objective of the test was met

  15. Control Systems with Normalized and Covariance Adaptation by Optimal Control Modification

    NASA Technical Reports Server (NTRS)

    Nguyen, Nhan T. (Inventor); Burken, John J. (Inventor); Hanson, Curtis E. (Inventor)

    2016-01-01

    Disclosed is a novel adaptive control method and system called optimal control modification with normalization and covariance adjustment. The invention addresses specifically to current challenges with adaptive control in these areas: 1) persistent excitation, 2) complex nonlinear input-output mapping, 3) large inputs and persistent learning, and 4) the lack of stability analysis tools for certification. The invention has been subject to many simulations and flight testing. The results substantiate the effectiveness of the invention and demonstrate the technical feasibility for use in modern aircraft flight control systems.

  16. Using adaptive structures to enable future missions by relaxing ground test requirements

    NASA Technical Reports Server (NTRS)

    Wada, Ben K.; Fanson, James L.; Chen, G.-S.

    1991-01-01

    Future NASA missions will require large space structures that must maintain accurate surface tolerances for up to 20 years; most flight programs require a ground test verification of the hardware. Because of the influence of gravity, the current state-of-the-art ground test technology cannot accurately determine whether the hardware complies with the requirements. The incorporation of adaptive structures into the spacecraft will enable a relaxation of the ground test requirements necessary to validate the hardware for flight. This paper describes the challenges in testing large precision structures, adaptive structures, the data establishing the current state of the art in ground testing, and the utilization of adaptive structures to alleviate the ground test requirements.

  17. Enhancing Adaptive Filtering Approaches for Land Data Assimilation Systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  18. Error magnitude estimation in model-reference adaptive systems

    NASA Technical Reports Server (NTRS)

    Colburn, B. K.; Boland, J. S., III

    1975-01-01

    A second order approximation is derived from a linearized error characteristic equation for Lyapunov designed model-reference adaptive systems and is used to estimate the maximum error between the model and plant states, and the time to reach this peak following a plant perturbation. The results are applicable in the analysis of plants containing magnitude-dependent nonlinearities.

  19. The New Trends in Adaptive Educational Hypermedia Systems

    ERIC Educational Resources Information Center

    Somyürek, Sibel

    2015-01-01

    This paper aims to give a general review of existing literature on adaptive educational hypermedia systems and to reveal technological trends and approaches within these studies. Fifty-six studies conducted between 2002 and 2012 were examined, to identify prominent themes and approaches. According to the content analysis, the new technological…

  20. Modeling Students' Memory for Application in Adaptive Educational Systems

    ERIC Educational Resources Information Center

    Pelánek, Radek

    2015-01-01

    Human memory has been thoroughly studied and modeled in psychology, but mainly in laboratory setting under simplified conditions. For application in practical adaptive educational systems we need simple and robust models which can cope with aspects like varied prior knowledge or multiple-choice questions. We discuss and evaluate several models of…